Machine design, tập 84, số 17, 2012

NOVEMBER 8, 2012 MACHINE DESIGN.com 60 MOTION CONTROL Rollers with polymer bearing surfaces work with aluminum rails, which cost far less than ground- hardened-steel versions.. Regardles

WITH AIR LOGIC ,

page 60

M i c r o h y d r a u l i c s

M a c r o c a p a b i l i t i e s

Lee Shuttle Valve Shown actual size.

Designed to isolate the normal from the emergency hydraulic sys- tem So small,

it fits right into the head

of an actuator.

W e s t b r o o k • G e r r a r d s C r o s s • P a r i s • F r a n k f u r t • M i l a n

So much reliability and performance, in so little space.

Creating high-performance flow control on a micro scale has been

The Lee Company’s exclusive focus for more than 50 years And

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Lee Microhydraulics designs – ranging from less than 0.10 in to 1.00 in

in diameter, and 0.1 to 68 grams, for operating pressures to 8,000 psi

But small size and light weight are just the beginning.There’s

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that has enabled Lee to meet demanding application needs in all

sorts of industries Aerospace, medical instrumentation, automotive,

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The innovative problem solvers.

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The Lee Company is the world’s most capable and proven source

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An invaluable reference, the Lee handbook contains essential data

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Lee Shuttle Valves Detented, spring-biased, inverse,

loose ball and zero leak shuttle valves from 50-700 Lohms.

Lee Safety Screens Best protection for critical system

elements 75 to 500 micron hole size Pressures to 7,500 psid.

Lee Pri Pressure relief valves in insert form.

50 to 400 Lohm capacity 20 to 5,400 psid cracking pressures.

Lee Directional Flow Control 40 to 20,000 Lohms

in metered direction 12 to 470 Lohms in free-flow direction.

Lee Restrictors Single and multi-orifice restrictors.

200 to 2.2 million Lohms.

Lee Plugs The best way to seal drilled holes to 32,000 psi.

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4 to 400 Lohms.

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Innovation in miniature.

RS# 101

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RS# 102

FLUIDPOWER TECHNOLOGY GUIDE

logic can also be used on machines with fluid-power ponents but no electrical supply.

com-Air logic does have disadvantages Most common is

a lack of understanding among maintenance personnel Also, air logic with long control lines responds notice- ably slower than electronics That’s because control lines

Electrical and electronic devices such as logic circuits, can also operate with “air logic,” controls that function while the circuitry is similar, compressed air is the con- trol medium instead of electric current.

Air-logic controls are often preferred in wet or dusty environments because they pose practically no danger of explosion or electrical shock Likewise, air controls can- not ignite explosive or flammable gases and vapors And

Pneumatic controls are

a viable option when electrical hazards can’t

• Air-logic controls are preferred in wet or dusty conditions because they pose little danger of electrical explosion or shock.

Resources:

AOP Technologies, www.aoptec.com

Clippard Instrument Laboratory,

www.clippard.com RS# 621

Magnum Venus Plastech, www.mvpind.com

How to … AVOID ELECTRICAL HAZARDS with

air logic

Air-logic controls for composites manufacturing rely on miniature valves, manifolds, and other components from Clippard Instrument Laboratory.

NOVEMBER 8, 2012 MACHINE DESIGN.com 60

MOTION CONTROL

Rollers with polymer bearing surfaces work with aluminum rails, which cost far less than ground- hardened-steel versions.

More importantly, cation puts an end to the loss

self-lubri-of performance and catastrophic failures common when metal rollers and rails aren’t regularly lubricated.

• Wear resistance Metal-on-metal contact, even when both metal surfaces

are lubricated, can result in excessive wear and galling Metal-on-metal wear eliminate this wear.

• Clean running Self-lubricated polymers eliminate two potential sources of

contamination — stray metal contact For this good choice for medical, room applications.

• Smooth and quiet

oper-ation. Unlike metals, polymers can dampen absorb the damaging shocks and vibrations the life of machine bear- speed applications.

In rollers, ing contributes to quiet motion Polymer roll- ers typically run about metal counter par ts

damp-They run smoothly too, total runout on a ma- chined nylon 12 cam

±0.001-in.

• Speed and efficiency.

Polymer rollers facilitate ways First, polymer rollers weigh about 40%

lowers is to transmit motion rather than support loads.

Regardless of their purpose, rollers and followers are commonly hybrid designs with polymer load-bearing sur- faces over metal roller bearings or structural hubs These technical advantages due to their use of polymers:

• Self-lubricating Engineering polymers best suited for

rollers are self-lubricating, a property that last the life of the component

polymers never require lubrica- tion between the with lubed-for-

l i f e b e a r i n g s , polymer surfaces eliminate main-

t e n a n c e c o s t s associated with regular lubrica- tion, even those

Engineers might only glance at the dimensions and load pay closer attention because these components can make

to a host of industrial machines.

Choose the wrong roller or cam follower and your design can be destined for a shortened life plagued with limitations The wrong component can also drive up oper- ating and manufacturing costs The right components, by that engineers and buyers expect.

But how do you pick the right roller or cam follower for the job at hand?

The trick is considering not just sizes and loads but also the materials that make up the roller’s bearing surface.

The polymer advantage

Many engineers still believe that heavily loaded plications need metal rollers and cam followers They are unaware that polymer bearing surfaces withstand enor-

ap-mous forces if designed properly At Intech Power Core,

Closter, N J., for example, we’ve delivered polymer ers that withstand 8-ton loads These rollers have been used in ski lifts and rigs that can raise an entire build-

roll-Polymer bearing surfaces resist wear, don’t need maintenance, and can run surprisingly fast.

Intech Power Core, www.intechpower.com

For another feature on plastic parts, scan this

code or go to: http://

outlast-metal-0506

How to …

GET BETTER MOTION with

most-ex-From a materials standpoint, Power-Core tains its physical properties in a variety of operating it’s exposed to varying moisture, temperature, and chemical levels.

main-In particular, Power-Core’s stability despite high-humidity and even total immersion, makes ture, swell, and lose tensile strength Power-trans-

to carry the loads they were designed for and too swollen to work with mating components.

Power-Core also dampens vibrations, which lets it reduce noise and absorb shock loads that power-transmission components commonly see.

To make these components, Intech gravity casts nylon 12 over metal hubs or thermally installs then precision machine into fi nished components

crystalline structure As a result, fi nished And under external load, the dense crystalline

compo-Cam followers and rollers from Intech put a gravity- cast nylon 12 bearing surface

on metal hubs and roller bearings

Using nylon eliminates the need for lubrication and makes the components quieter than their all-metal counterparts.

NOVEMBER 8, 2012 MACHINE DESIGN.com

Access our Reader Service Web site to quickly find and request information on the products and services found

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60

VOLUME 84ISSUE 17NOVEMBER 8, 2012

38





How to get better motion

with plastic parts

Rollers, cam followers, and other

components used for moving parts can make

good use of polymers to increase speeds,

reduce wear, and resist chemicals and harsh

environments They’re also quieter than

metal components

How to design suppression

circuits for electric

clutches and brakes

Back-EMF in clutches and brakes may lead to

erratic operation and a shortened life

How to rid foam of petroleum

A biodegradable alternative to foam is grown

from mushroom roots and agricultural waste

MACHINE DESIGN’s

Literature Express

How to avoid electrical

hazards with air logic

Pneumatic controls are a viable option when

electrical hazards can’t be tolerated

2

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RS# 103

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SCANNING FOR IDEAS

Liquid cooling for servers also supplies hot water

Gimbal mount expands drones’ view

We’ve all seen fl at air nozzles Some are yellow Others are orange Th e oldest

ones are blue or metal Th ose other manufacturers want you to believe you’ll

save money by conserving compressed air while protecting your workers from

harmful noise levels In reality, those colorful air nozzles that blow the air out

of holes consume enormous amounts of air Th e plastic ones often break off

Some might even get you an OSHA fi ne due to the dangerous dead ended

pressures that exist if someone blocks the air exhaust

EXAIR’s award winning 2" Super Air Nozzle™ has been engineered to replace

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the force of each fl at air nozzle – using shims to tune it to the application so

you’ll never waste compressed air

Flat nozzles from other manufacturers can consume over 30 SCFM

(a refrigerator sized compressor) and aren’t adjustable Some manufacturers

off er diff erent fl ow rates but you need to guess at which one will do the job since

you can’t adjust them once you’ve made the purchase By default, most users feel

bigger is better and go with the highest fl ow rate, wasting compressed air

Metal (machined) 29 SCFM 82 1.7 Metal (cast) 31 SCFM 80 1.9 EXAIR 2" Super Air Nozzle *7.3- 30 SCFM 62-81 0.5 – 1.9

*Air consumption dependent upon shim size.

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Most large plants know their cost per 1,000 standard cubic feet of compressed air If you don’t know your actual cost per 1,000 SCF, 25¢ is a reasonable average to use.

• SCFM saved x 60 minutes x cost/1,000 SCF = dollars saved per hour.

• In this case, 9.2 SCFM x 60 x 25/1,000 SCF=

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• 13.8 cents per hour x 24 hours =

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RS# 104

A new 140-page catalog from iwis

drive systems covers the design,

selection, and application of a wide

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drives There’s also a section on

lubricants and lubrication methods

Request or download a copy at www.

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Power-supply site

Mouser Electronics has launched

a new Power Supply site It contains

technical and design information,

including the benefits of

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UPS and ac/dc applications Content

includes product data, white papers,

a library of technical resources,

and info on products from major

manufacturers Visit www.mouser.

com/power-supply-technology.

Dealing with digital

The Agilent Technologies

High-Speed Digital site (www.agilent.

com/find/HSD) covers test and

measurement products such as oscilloscopes, analyzers, and meters

It delves into topics such as signal integrity, design and simulation, and high-speed digital analysis, and offers debugging tips The technical support area includes a library, FAQs, and discussion forums And

a new white paper, “Crossing the Digital-Analog Divide,” explains how digital signals are idealized at high data rates, as well as how to cope with the physical nature of signals that engineers might prefer to think

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application profiles, service manuals,

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Power everything via USB

The president of the USB Implementers Forum gives an overview of the new

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RS# 106

In return for boosting H-1B quotas, Microsoft would have Uncle Sam charge companies $10,000 per additional H-1B worker It also suggests charg-ing employers $15,000 per STEM green card over the current quota So far, so good Employers should be willing to pay a stiff fee if they feel their needs are urgent enough to hire outside the U. S I’d even suggest setting the fee at levels far higher than what Microsoft has in mind as a way of making employers show they are serious.

But interestingly enough, Microsoft also wants fees collected from card permits to be invested in STEM education Microsoft claims such mea-sures are necessary because it has 3,400 open jobs for scientists and engineers while the U. S last year minted only 1,603 new computer science Ph.Ds

green-Of course, industry has for decades leveled allegations of shortages as a tionale for letting more foreign skilled workers enter the U. S But researchers

ra-at the Bureau of Labor Stra-atistics have studied the impact of letting in foreign Ph.Ds and concluded that the result is a downward pressure on Ph.D salaries This downward pressure tends to discourage aspiring scientists from pursuing higher degrees The result: The smartest of them go where the money is, which, today, is still in finance There, new financial engineers can still earn six-figure bonuses in the first year on the job

Thus, Microsoft’s idea for new H-1B fees seems self-defeating The tion it funds would create more workers in areas now being filled by foreigners But filling jobs with foreign workers reduces pay scales and makes jobs in that area less attractive One might be excused for seeing this whole process as a negative feedback loop for the process of minting STEM Ph.Ds in the U. S

educa-So here is an off-the-wall idea for what to do with U. S STEM graduates

in an era when STEM jobs get filled by foreign workers: make it easy for U. S technical personnel to become Canadians

Workers with easy access to our Northern neighbor would have more tions if salary levels take a hit from an influx of foreign workers And indica-tions are that Canada might be open to this idea “The Government of Canada

op-is committed to building an immigration system that actively recruits talent,” said a Canadian minister recently “This is the next frontier in Canadian immi-gration: looking at opportunities to attract the best talent and going out there and getting it,” he continued

A representative of the Canadian government even went to Ireland a few months ago to beg STEM graduates there to try living in Canada The labor situation for STEM workers in Canada is so tight that its government officials are entertaining the idea of instituting special benefits for Canadian STEM personnel willing to work past the age of 65 — not because they lack the money

to retire, but because they are so difficult to replace

One other point in Canada’s favor: There’s no out-of-control financial tor in that country run by individuals making obscene salaries

— Leland Teschler, Editor

Listen to the difference.

Our fans for cooling and refrigeration technology are already among the quietest and most efficient in the world How can we top that? Easily: with the new AxiTop diffuser It optimizes air flow at the impeller exhaust, significantly increasing efficiency This means up to 7.2 dB(A) of noise reduction and up to 27% lower energy consumption at the same flow rate for your refrigeration application Or up to 9 % more air performance with comparable energy consumption!

If this sounds like music to your ears, visit info.ebmpapst.us/AxiTop for more information.

the engineer’s choice

RS# 108

Moving Assembly Lines

for the Heaviest Products

Powered by Proven, Versatile Air Film Technology

MANAGING EDITOR Kenneth J Korane ken.korane@penton.com

SENIOR EDITORS Leslie Gordon leslie.gordon@penton.com Stephen J Mraz stephen.mraz@penton.com

ASSOCIATE EDITORS Lindsey Frick lindsey.frick@penton.com Robert J Repas, Jr.

robert.repas@penton.com

INDUSTRY COVERAGE: AUTOMOTIVE, PACKAGING,

MEDICAL Stephen J Mraz

CAD/CAM, MANUFACTURING

Leslie Gordon

ELECTRICAL, ELECTRONICS Robert J Repas, Jr.

FASTENING & JOINING, MATERIALS Lindsey Frick

FLUID POWER Kenneth J Korane

MECHANICAL Lindsey Frick Kenneth J Korane

EDITORIAL PRODUCTION Denise Greco Editorial Production Manager Randall L Rubenking Art Director

RS# 110 RS# 109

NOVEMBER 8, 2012 MACHINE DESIGN.com

10

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RS# 111

no high-tech work gets done in nessee, that’s where the Manhattan Project was carried out

Ten-By the way, I live in New Jersey, a part of the country that gets almost

as much abuse as the south

Dudley M Jones

I would advise the reader who didn’t like Tennessee that if he doesn’t already live in California, then please do the rest of us a fa-vor and move there To insinuate that “smart people don’t want to be anywhere but California” shows just how ignorant you are And please don’t try to imply that all engineers share your opinion

I believe Nissan is on the right track by relocating They will prob-ably attract a substantial amount

of engineering talent that would be much happier in Tennessee (both

on and off the job) than in the freak show called California

Cadiero Gregg

To paraphrase my mother, if you can’t say something nice about a state, don’t say anything at all — Editor

They’re stifling me, and you

Most scientists, engineers, and technical employees who have jobs don’t control their creative brains anymore Their employers do

For example, I developed a new farm product in my own basement shop that was totally unrelated to

my day job in the defense industry

My employer claimed my tion based on the fine print in the

inven-Stop dissin’ Tennessee

After I read a letter to the editor

(“Ev-eryone Loves LA,” Sept 6), I knew

that I would have to comment The

reader says that the reason that only

42% of Nissan’s workforce

relo-cated to Franklin, Tenn., is because

people don’t want to live in

second-rate locations I’m not sure what

he means by this, but it is obvious

he has never been to Franklin and

probably doesn’t know it is a suburb

of Nashville

Franklin has consistently been

rated in the top cities in the

coun-try to live based on cost of living,

education, quality of life, and other

factors In fact, quite a number of

large corporations are located in

or near Nashville, and many have

their headquarters in the Nashville

area These include companies

like Mars Petcare, Caterpillar

Fi-nancial, Bridgestone/Firestone,

Louisiana Pacific, Caremark, and

Asurian It’s also home to Nissan’s

Smyrna plant and General Motors’

Spring Hill plant And although

many of these companies do not

necessarily have a lot of engineers

located in Middle Tennessee, they

understand that the quality of life

for their employees, the low cost of

living and tax rates, and access to a

highly educated workforce make it

a great place to set up shop (There

are 18 institutions of higher

educa-tion in Middle Tennessee.) In

addi-tion, middle Tennessee is within 650

miles of over 150 million people

And by the way, I was born

and raised in the Detroit area and

couldn’t wait to leave I didn’t

con-sider it a first rate place to live

And as far as LA is concerned, you

couldn’t pay me enough to live

there

Jim Johnson

Making snide remarks about

Ten-nessee is not helpful We are all in

this together, and when people talk

like that about the heartland, they

only increase the resentment felt

by Midwestern conservatives They

are already mad enough at the rest

of us

And as far as the comment that

crippling “Employee Agreement” I had signed earlier as a condition of employment He didn’t even want the invention He just wanted to crush any inkling of outside entre-preneurship arising from any of his employees No wonder we are stuck with millions unemployed despite adding $3 billion to the national debt every day

We need a federal “Use or Return” law to restore creative incentives and protection intended by our Founding Fathers when they estab-lished the U. S Patent Office back in

1790 It might give American ployees the creative freedom nec-essary to create the new business and private-sector jobs we so ur-gently need

em-Robert Nepper

It has been my experience after working with manufacturers all over the world, that U. S has the best and most-creative engineer-ing talent in the world Our biggest problem is that our management does not understand or accept this talent Most engineering tal-ent is not recognized but, in fact, repressed, is because it would in-volve company politics

The head of a large turing company once commented

manufac-to me, “We have been doing it our way for 50 years, so why would

we change?” I’ve also heard: “We tried something 30 years ago and

it didn’t work.” What they really mean is that many manufacturing companies want to run production the same way they’ve always run

it And they expect engineers to

Don’t tread on Tennessee

Many readers volunteered

to stick up for Tennessee against an earlier letter writer who didn’t seem to have too high an opinion

of that southern state other reader bemoans the small print in his employ-ment agreement

An-NOVEMBER 8, 2012 MACHINE DESIGN.com

12

RS# 112

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LETTERS

LETTERS TO THE EDITOR

Please include your name, address, and daytime phone number Letters may

be edited for brevity and to focus on essential points.

Mail: Letters, M ACHINE D ESIGN ,

1300 E 9th St., Cleveland, OH

44114-1503, Fax: 216-621-8469 E-mail, Editorial:

mdeditor@penton.com

keep fixing old equipment when it

clearly is no longer fixable

It seems there’s always that one

guy in the big corner office that

doesn’t want to evolve and is just

waiting it out until retirement

But that same guy will hound

ev-ery employee for better

produc-tion rates, less maintenance issues,

and so on The last thing he wants

is to invest in new equipment to

run leaner and smarter

produc-tion through modern engineering

ideas and technology After all, he

might make a mistake

Paul Pfundtner

Bring on the TechShops

I do hope this TechShop effort

pros-pers and spreads (“Manufacturing

for the Masses,” Sept 6)

There use to be a business called

MonkeyWrench, which rented out

tool shops to do-it-yourself auto

repairmen (and women) But the

Corrections:

A c q u i s i t i o n s — T h e L o r d Corp., Cary, N. C., is purchasing MicroStrain Inc., Williston, Vt

(“Company News,” Oct 4)

B-2 Bomber — The fine news

item on UAVs (“More tion for carrier-based UAVs,” Sept 20) has a small but notable error

competi-Northrop Grumman is the

de-signer and developer of the B-2

Spirit, not Boeing.

Jack Fagan

business didn’t do as well as I had hoped One set of reasons for the lack of success was the increas-ing difficulty of working on cars and trucks for those not trained

to deal with the computerization

of today’s vehicles, the need for electronic-analysis equipment, and densely packed engine com-partments in almost all new cars I presume and hope that TechShops will not run into similar problems

I would love to see them become commonplace I n my humble opinion, the business deserves public funding and support If we are to be a more innovative coun-try, this kind of facility ought to help From personal experience,

I know that getting parts from machine shops is not easy or in-expensive With the small budget most inventors have, this kind of resource could be a real boon to

me and people like me

Mark Stapelton

RS# 113 NOVEMBER 8, 2012

MACHINE DESIGN.com

14

Solutions for Automation That Take You Straight to the Top

Unrivaled in scope and versatility, Schaeffler’s linear product line rangesfrom shafts with linear ball bearings and monorail guidance systems to so-phisticated actuators with drives and control systems, plus special coatingsand every conceivable accessory You name it, we’ve got it

But that’s only the start Our linear portfolio is based on a modular conceptthat goes far beyond mere components We can design a complete systemsolution tailored to your specific application - from large gantry robots tointricate circuit board inspection systems In fact, many of our linear guid-ance systems started out as solutions to customers’ needs!

SCANNING FOR IDEAS

Edited by Stephen J Mraz

Request free information vi

a our Reader Service Web site atwww.machinedesign.com/

high-density and blade

servers The coolant

is a nonproprietary

odorless, white

mineral oil which was

chosen for its clarity,

low viscosity, high

flash point, and high

specific heat capacity

To ensure

servers can survive

submersion in

the coolant, GRC

removes the fans and

encapsulates the hard

drives Also, servers

typically use thermal

grease to help heat

sinks remove heat

In the CarnotJet, it

gets replaced with a

covering of indium,

a soft metal foil with

Liquid cooling for servers

also supplies hot water

high-heat conductivity

Coolant is pumped

through a heat exchanger,

where it gives up its heat to a

stream of water A pump module

containing variable-speed, digitally

controlled pumps and heat exchangers

can handle the thermal demands of up to

four racks of servers And the coolant should last

10 years or more, roughly the life of the system

Using this equipment instead of an arsenal of chassis

and power-supply fans cuts a server’s energy use by 5 to 25%

and reduces the amount of energy used for cooling by 90 to 95%

It also lets the servers be packaged in a smaller enclosure The

closed-loop liquid cooling and pump are also significantly quieter than

the fans they replace And water comes out of the heat exchanger at

122°F and can be sent to an evaporative cooler or serve as a source of hot

waste for a secondary purpose such as heating nearby buildings

RS# 401

CarnotJet

vertically installed in coolant bath Heated coolant exits at top of rack

Coolant pump

Coolant-to-water heat exchanger

Evaporative cooling tower releases heat to the atmosphere

NOVEMBER 8, 2012 MACHINE DESIGN.com

16

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6SHHGVDUHEDVHGXSRQSULQWHQJLQHVSHHGRQO\7RWDOWKURXJKSXWWLPHVGHSHQGXSRQIDFWRUVVXFKDVFRPSXWHUILOHVL]HSULQWHUUHVROXWLRQLQNFRYHUDJHDQGQHWZRUNLQJ)RUWKH6&7WRSVSHHGIRUD'VL]HGSORWLVVHFRQGV

3ULFHVDUH0653EHIRUHUHEDWHV3OHDVHFKHFNZLWKDQ(36213URIHVVLRQDO,PDJLQJ$XWKRUL]HG5HVHOOHUIRUDFWXDOSULFHDVGHDOHUSULFHVPD\YDU\

(3621DQG6XUH&RORUDUHUHJLVWHUHGWUDGHPDUNVDQG(3621([FHHG<RXU9LVLRQLVDUHJLVWHUHGORJRPDUNRI6HLNR(SVRQ&RUSRUDWLRQ&RS\ULJKW(SVRQ$PHULFD,QF

RS# 115

*HDUKREELQJDQGJHDUJULQGLQJIURPμ²μ$*0$ ,QWHUQDOJHDUJULQGLQJIURPμ²μ

&1&JHDULQVSHFWLRQXSWRμ

*HDUVKDSLQJWRμLQGLDPHWHUμIDFHZLGWK

'HVLJQDQG$QDO\VLVH[FHOOHQWVRIWZDUHFRP 5HYHUVHHQJLQHHULQJVHUYLFH

ZZZ([FHO*HDUFRP

SCANNING FOR IDEAS

Gimbal mount expands drones’ view

The new gimbal designed by

engineers at Ross-Hime Design

Inc in Minneapolis (anthrobot.

com), will give cameras and other

sensors mounted on military

UAVs 180° of horizon-to-horizon

tracking The device, dubbed the

Omni-Wrist VI, also uses fewer

motors and other expensive

components than previous designs

This version eliminates the keyhole or gimbal lock, as well as any rotary joints, twist capsules, and other rotary wire-handling devices Instead, a simple through-hole lets wires, cables, and fiber optics pass through

the faceplate to the base of the unit The new gimbal has

a repeatability of 35 arc-sec, a twofold improvement over its 10-year-old predecessor The cost and size of the Omni-Wrist VI will

be similar to those of previous designs

Through-Harmonic-drive actuator

Ball-and-socket joint

Preloaded

tapered-roller

bearings

NOVEMBER 8, 2012 MACHINE DESIGN.com

18

ty>dd,K^ĂŵŽŶŐŽƚŚĞƌƐƚŚŝŶŐƐ

:,7+48$/,7<72$*0$"

RS# 117

REPORTER’S NOTEBOOK

The 200-mph drag bike sitting in

Shawn Lawless’ shop sports an

electric motor that once was rated

at 29 hp Today, the bike’s power

plant, made by GE and salvaged

from an old forklift, puts out

some-where north of 800 hp

Welcome to the world of

elec-tric drag racing, where racers

mod-ify their motors in ways analogous

to how traditional hot-rodders

boost engine displacement and

crank stroke But don’t expect to

find many tips on electric motor

hot rodding in online forums or

magazines Today, many of those

tricks come close to being black

arts practiced by a few gurus

One of the most accomplished

of these practitioners, at least in

the eyes of drag-biker Lawless, is

Dennis Berube Berube souped-up

the electric motor that sits in

Law-less’ 200-mph drag bike Berube

also claims to be the fastest tric drag racer on four wheels, hav-ing piloted an electric dragster he built to 159.85 mph in a 7.956-sec run down the quarter mile

elec-Berube had his first inklings

of how electric motors could be modified two decades ago when

he got a job repairing and ing armatures While learning his craft, he worked with a German engineer “who gave me a lot of good tips about dc motors,” he says But most of his knowledge comes from 23 years of experi-menting with his own race cars “In evaluating an idea, you have to be diligent about documenting your setups And you have to try the idea for one or two months, not change something after every run,”

rewind-he says.” “That’s why I have over 4,000 time slips from quarter-mile runs with my electric dragsters.”

As you might expect, both Berube and Lawless are a bit cagey about discussing the details

of their motor modifications But they are willing to broadly outline how to turn an old motor from the scrap yard into something ready to challenge quarter-mile records.All electric motors for drag racing are dc series-wound mo-tors, rather than induction motors

or something else more exotic, because “dc motors are torque monsters They have extremely high-starting torques from 0 rpm,” notes Lawless

Modification typically starts with installing low-friction, low-drag bearings on the motor shaft Next, parts within the motor that are nonconductive get extra insu-lation, such as a layer of powder coating, to minimize the potential for arcing This step is not taken

this, his latest race car,

but an earlier version

hit about 160 mph in

a quarter-mile run of

under 8 sec.

NOVEMBER 8, 2012 MACHINE DESIGN.com

Armature windings

Brush motor in cross section

Commutator Series field windings

Case Leads

Armature Brushes

lightly “After all, we are taking

a motor designed for 200 A and

putting 2,000 A through it,” says

Lawless

Meanwhile, all the motor’s

con-ductive parts are typically replaced

with beefed-up versions The

com-mutator gets special attention

“You can run direct leads into each

commutator mounting point —

in other words, get rid of parallel

links within the commutator itself

— or just make them a lot bigger,”

explains Lawless

Racers sometimes modify the

motor windings as well “Some

people change the field windings

depending on the specific rpm

and torque levels they are trying

to get They may also shim the

field windings to put them closer

to the armature, but that depends

on whether you are optimizing for

torque or rpm You are effectively

altering the motor gearing when you tweak design parameters like that,” explains Lawless

Finally, drag racers know when

to shut things down “You can’t run the motor long because it only has so many windings,” says Berube “You are eventually going

M ACHINE D ESIGN covered Shawn Lawless’ electric

drag bike earlier this year: machinedesign.com/

an 11.08-sec quarter-mile run.

Motor components don’t appear

to scale in this basic diagram of

a dc series-wound motor Motors

modified for racing typically

contain severely beefed-up

conductive components.

NOVEMBER 8, 2012 MACHINE DESIGN.com 21

REPORTER’S NOTEBOOK

How to upgrade a CAD file

Your best bet in upgrading a CAD file from one format to another is to first store the source CAD file in a neutral file format, such as IGES or STEP A useful step might be to reorient the piece to a set of standard datum planes before the file is translated If you are sufficiently skilled, you may want to put in some highlighted or extra lines to ensure that hole centers and radii stand out

The trick in creating the neutral file format is that while you will make use of the key points, the final goal is to completely delete this intermediate content You will use the entire imported file as a mass of construction lines Using the tools in the target CAD system, you will then rebuild the part Independent of the CAD system, you should try

to use similar techniques to build similar parts For example, all tubes should be constructed from a part profile in the front plane A common orientation makes the creation of shop drawings and parts assemblies easier

How to convert technical manuals

It sometimes becomes necessary to convert a technical manual from Format A to Format B as, for example, from

MS Word to Framemaker There are ways to avoid ing a career out of this job The techniques suggested below are relevant

mak-to any massive data conversion Your goal is mak-to achieve 100% fidelity, fast.The takeaway in any data migration project is that the process moves best with the least excess information In most cases, there is a source document or example that shows what the new format should look like

To ensure content fidelity, save the content as a format-free, straight text file In any document, the “body” is the bulk of the content Titles, captions, comments are all separate formats, but you will still make just one or two lines per page in a different format

Next create an empty shell document (as you would create a “blank” CAD file) This shell should have all the existing standards (such as page layout, paragraph types, font choices, pagination, and so on) built in The content for each chapter is then inserted as a cut-and-paste One further hint in this process is to save each dummy chapter as “body” or plain para-graph text This way, when you import the unformatted text file, the bulk

of the material is already in the “correct” format

Some text applications, such as Framemaker, support the use of stroke commands for changing formats The mouse-and-menu process for making format changes is cumbersome but to those with extensive CAD experience, keystrokes are much faster To further simplify the process, you will, of course, have already printed out a copy of the source docu-ment so you can pattern-match the original and revised documents

key-In the case of a 350-page manual initially in MS Word that had to be turned into Framemaker, use of the above techniques led to finishing the conversion in two days Each chapter took about a minute/page to format,

or 20 min/chapter On a historical note, at one point IBM computed that

it took 8 hr to write, edit, and format each page in a technical manual But this number was from the 1970s, quite a few years before the advent of

What you get in

return is a CAD file

in the new “native”

format And this file

can be edited To be

sure the file is absolutely free of any

extra-neous data, you can select the new CAD

geometry and place this in an empty file

While you want the geometric fidelity, the

last thing you want to import in a “live” file

is extraneous data, or in the case of a

docu-ment file, extraneous formatting

The hazard of this whole process is that

when you re-create the assembly, you will

likely see errors as the parts might not

quite match Finding and fixing these error

is an entirely different problem. MD

How to build

an airplane at

home

In a trend called “personal manufacturing,” local

shop facilities like The TechShop have given

ev-eryday people access to tools typically available

only to industry The shops let individuals more easily make everything from

furniture to cargo bikes Well, hold on to your hats MakerPlane.org wants

to help DIYers build airplanes at its facilities, dubbed makerspaces, or even

at home The Web site invites educated visitors to submit improvements to

the basic Light Sport Aircraft open-source design, MakerPlane Version 1.0,

introduced last year When the final design is complete, MakerPlane

engi-neers will build the craft and the site will let users download plans and 3D

animated instructions for free

“Until now, a big problem has been that nearly three out of four aircraft

projects started by home builders — either from kits or from parts — are

abandoned before they ever fly,” says MakerPlane founder John Nicol

“Rea-sons include poor instructions and complicated assembly, plus it takes more

tools and skills than many people realize So we decided to use collaborators

from around the world to develop a design that would let home builders

take advantage of modern personal-manufacturing equipment such as CNC

machines and 3D printers This makes sense because makerspaces are

crop-ping up almost everywhere.”

Nicol points out that MakerPlane does not intend that people build

struc-tural components using 3D printers, just items like door handles and knobs

And in terms of safety, “We are not letting just anyone make design changes

to the aircraft,” he says “Our aeronautical engineer, frey Meyer, acts as a gatekeeper for all design activities and, as such, must approve changes.”

Jef-In addition, every experimental aircraft must be proved and inspected before it flies In the U. S., the FAA handles this It sends an FAA staffer to your house and they check your aircraft for compliance “It is up to you as the pilot and builder to be safe,” says Nicol “But there are all sorts of regulatory hurdles to overcome before you can fly You must even have a pilot license.”

Submit your ideas for

the plane design or

instruments through

the online forum or

at IdeaForge (under

Tools) on the Web site.

An artist’s rendering shows what the MakerPlane aircraft will look like.

To sustain itself and maybe make a profit, MakerPlane will sell kit sets, avionics, and other parts Users can also source parts from anywhere

“There will always be people who will build the aircraft from scratch and who have all the resources they need,” says Nicol “But there will be others who want to shorten the time

it takes to build a craft by ing a kit or parts.”

us-MakerPlane intends to have a nonflying prototype

at the AirVenture air show in Oshkosh, Wis., July through August 2013 It hopes to have

an aircraft flying at the 2014 show. MD

RS# 119 NOVEMBER 8, 2012

Nanotube transistors fit for space

Researchers at the U. S Navy

Re-search Laboratory in Washington,

D. C., are designing single-walled

carbon nanotube-based

tran-sistors (SWCNT) that are

pro-tected against the ionizing

radiation found in outer

space and the Van Allen

Belt, a ring of charged

par-ticles circling Earth This

radiation can degrade ICs,

interfere with their proper

operation, and lead to

pre-mature failures

Radiation affecting ICs

takes two forms In one, an

ionizing particle makes a direct hit on the transistor, which can corrupt

data and signals But the chances of such a hit on a SWCNT is small due

to their tiny size, low density, and inherent isolation from other SWCNTs

in a device, according to Navy scientists The other form results from the

cumulative effect of charges trapped in electronic devices’ oxides,

includ-ing the gate oxide and those that isolate adjacent devices These trapped

charges shift the voltage needed to turn the transistor on or off, which

leads to power leaks and eventual failure of the entire circuit

To prevent charges from accumulating, researchers built a SWCNT with

a thin gate oxide layer made of silicon oxynitride This hardened dielectric

material keeps out stray charged particles

Making SWCNT “spaceproof” means future circuitry on spacecraft will

have less redundancy and error-correction circuity than today’s

space-bound ICs and electronic equipment This would reduce costs and power

consumption while improving performance, even if SWCNTs operate at

the same speed as present day circuits. MD

RS# 120

(952) 927-1400

www.mnrubber.com

Minnesota Rubber & Plastics

Engineered to improve performance Designed to reduce costs.

High tolerance components and assemblies are

what we work with everyday at Minnesota Rubber

and Plastics Our experience in design, sealing and

manufacturing complex devices has made us the

preferred partner for industry leaders throughout

North America, Europe and Asia The next timeyour component or assembly seems impossible,there's no one better to partner with than MinnesotaRubber and Plastics We'll make your toughapplication a reality

We Mold Ideas Into Reality.

RS# 121

Phone 1-888-260-7466 Fax 516-771-6444

sales@ondrivesUS.com www.ondrivesUS.com/ServoBeam

.US Corp.

Misalignment 7º angular .025” radial .050” axial

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High torsional stiffness

Low weight to size ratio

Short and long versions

Flex member available in

Practicing to the extreme: If

you ever wanted to learn extreme

sports such as skateboarding,

snowboarding, or surfing, now’s

your chance Pivit LLC, Franklin

Lakes, N. J., has designed a durable

fiberglass balance board called Pivit

that lets riders jump, flip, balance, and spin The board is supported underneath by one wheel in the center The design lets riders safely practice tricks, foot-

ings, and techniques Removable per-style stabilizers help ease first-time riders through the learning process Optional built-in LED timers let riders measure their skills and practice for competition

bum-30 YEARS AGO — 1982

Handyman’s tool pinpoints air leak:

A $20 energy-audit tool called Thermo

Guard by Metrifast, New Hyde Park,

N Y., locates drafts around windows, doors, electrical outlets, fireplaces, and other places heat losses occur It even detects impossible-to-see insulation breaks behind walls, according to the com-

pany The battery-powered instrument

is ated by unscrew-ing the protective probe cover and setting the meter indicator to “normal.” When the heat-sensitive tip is pointed at a heat-loss (or heat-gain) area from a distance

oper-of about ½ in., the dial indicator clearly indicates the source of the problem Temperature sensitivity is 1/25 of a de-gree and effective operating range is from –58 to 167°F

50 YEARS AGO — 1962

Watering the lawn requires setting a

few dials with Moist O’Matic, made by

a subsidiary of Toro Mfg Corp.,

Min-neapolis The unit can be programmed for 14 days and controls up to 11 sepa-rate watering stations Days for water-ing, hour of the day, and duration of watering for each station are prese-lected A hydrostat — a porous ceramic vessel available with the system — is buried in the ground It senses when the soil’s moisture content is too low and triggers the Moist O’Matic into action Water-

ing can be controlled by the hydrostat;

by the preset program; or manually, for special water-ing needs MD

NOVEMBER 8, 2012 MACHINE DESIGN.com

26

PUMPS VALVES POWER UNITS

952 895 6400 | www.continentalhydraulics.com

RS# 122

INNOVATION MAKES

GGB THE PRODUCT LEADER

©2012 GGB All rights reserved.

The Global Leader in High Performance Bearing Solutions GGB listens to our customers

The result is superior bearings that eliminate problems

To learn more, visit ggbearings.com or scan the QR code below.

Get a QR code reader

at http://getscanlife.com

REPORTER’S NOTEBOOK

ACQUISITION

Lord Corp., Cary, N.C., has

pur-chased MicroStrain Inc.,

Willis-ton, Vt MicroStrain will continue

to operate at that location as

MicroStrain, a Lord Co.

Lord specializes in adhesive,

coating, and

motion-manage-ment technologies for the space, defense, automotive, and industrial markets MicroStrain develops and supplies sensing so-lutions to the aerospace, defense, agriculture and construction, energy, and consumer-electronics industries

aero-PROGRAMMING PLCs Omron Automation and Safety

is offering PLC programming training courses that let attend-ees complete basic and inter-mediate levels

in one week The training will be

at Omron’s quarters in Scha-umburg, Ill

head-Dates for the Fall schedule are: Nov 29-30 — Advanced PLC Programming (Course #IA-TRN-OES118); Dec 3–5 — Basic PLC Programming (Course #IA-TRN-OES110); Dec 6–7 — Intermediate PLC Programming (Course #IA-TRN-OES112)

Go to http://www.omron247.

com/Industrial-Automation/Store/ OmronTrngOmronUniversityView_- 1_10051_10051?location=US for

registration information

EXPANSION Omega Engineering Inc., Stam-

ford, Conn., has opened a new office in Shanghai, China Omega

was recently acquired by Spectris plc, a supplier of productivity

enhancing instrumentation and controls Omega manufactures products that measure and control temperature, humidity, pressure, strain, force, flow, level, pH, and conductivity

NEW SERVICE Agilent Technologies, Santa

Clara, Calif., has been designated

as the first nongovernment bration agency under Japan Radio Law by the Minister of Internal Affairs and Communications Un-der Japan law, calibration service

cali-is required for all test equipment used to maintain radio stations

in the country Agilent provides measurement services in the areas

of chemical analysis, life sciences, diagnostics, electronics, and com-munications

RS# 123 NOVEMBER 8, 2012 MACHINE DESIGN.com

28

RS# 124

SOLUTION FACTORY OPENS

SKF USA Inc., Lansdale, Pa., has

opened its SKF Solution Factory

in Highland Heights, Ohio It is the

second to open in the U S., joining

17 others worldwide Services the

facility offers includes bearing

application support, customized

machined sealing solutions, spindle and ball-screw repair, mechanical equipment services, engineering consultancy, remote diagnostics

and monitoring, and training courses.SKF is a supplier of bearings, seals, mechatronics, lubrication systems, and services

AWARD The Texas Workforce Commission presented Wichita Clutch,

Wichita Falls, Tex., with its Texas Manufacturing Star Award, which acknowledges outstanding private-sector employers that contribute to the growing manufacturing base in Texas Wichita Clutch designs and manufactures heavy-duty industrial pneumatic and hydraulically actuated clutches and brakes

PERSONNEL New England Wire Technologies,

Lisbon, N. H., has appointed Kelly MacKay as Sales Director, and Nick D’Agostino as Business Development Manager New England Wire Technologies develops, designs, and manufactures technologically advanced wire and cable products

SOFTWARE INTEGRATION SpaceClaim, Concord, Mass., and First Trace, Phoenix, Ariz., have

integrated SpaceClaim Engineer and Kinnosa SpaceClaim is a provider 3D software for engineering design and manufacturing, and First Trace offers Kinnosa, an Engineering Document Management (EDM) system for managing complex CAD documents, Office files, and business processes

AS9100 REV C CERTIFICATION BEI Sensors, Goleta, Calif., has

been awarded the AS9100 Rev C quality standard for aerospace The company met the nearly 100 additional rigorous criteria required

to meet the stringent, complex, and unique demands of aerospace manufacturing, from commercial

to defense aviation BEI Sensors provides speed and position sensors MD

RS# 125 NOVEMBER 8, 2012 MACHINE DESIGN.com

30

• Free 3D solid CAD drawings

• New, optional safety locks

on some styles

• Fast shipping

TOGGLE CLAMPS

EXCLUSIVELY MADE IN THE USA

You can count on Carr Lane to provide you with top quality,

American made toggle clamps in a variety of types, sizes and styles.

Visit CarrLane.com to view toggle clamps in our online catalog.

RS# 126

We’ll work hard to keep your plant buzzing using the most advanced sensing technology…all from

a single-source partner We’ve stayed busy as a bee for over half a century developing innovative products that take the sting out of applying sensors Our sensors are crafted using state-of-the-art components and the latest technologies

to ensure precision, reliability, and functionality

In addition, we offer a wide selection of accessories to meet all your application needs

Go to www.sensing.net/buzz1 or give us a buzz

at 330.486.0001 and we’ll devote a swarm of technical experts to go to work for you

EVERY PLANT NEEDS A PARTNER TO

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SENSOR SENSE

After a 20-hr abrasion test by a wire brush on

plastic and faced sensors, the

metal-face sensor on the left shows wear but still

works while the plastic-face sensor on the

right is totally destroyed.

Metal-faced

inductive sensors for durability

In quick review, an inductive sensor generates an electromagnetic wave at

a specific tuned frequency The tuned circuit inside the sensor has a high

impedance at that frequency, creating a high ringing voltage When any

metal is brought near the output coil of the sensor, the coil becomes

de-tuned This shifts the oscillator frequency and, more importantly, reduces

the ringing voltage in the sensor’s tuned oscillator circuit The lower

volt-age triggers the output that indicates the presence of the metal target

Most metal-detecting inductive sensors use plastic sensing faces

Plas-tic facings are inexpensive and do not interfere with the metal-sensing

ability of the sensor These products are an option when a sensing area is relatively benign

But plastic’s lack of durability may create problems in some situations

Inductive sensors feature comparatively short sensing ranges, often under a half-inch

Such close proximity to the get means even slight variations

tar-in target clearances or vibration may subject the sensor to dam-aging physical abuse The life span of a plastic-faced sensor

is greatly reduced under these circumstances

If an inductive sensor is to be used in abusive environments where impact and abrasion are commonplace, it’s now more common for the inductive sensor to have a

metallic face — specifically, stainless steel

The question arises, “How does the sensor detect the metal in the

tar-get, yet ignore the metal at the tip of its own housing?” To understand

how requires a quick look into electrical physics The trick hinges on the

oscillator frequency and the wavelength of the signal it produces

Metals such as copper, aluminum, and stainless steel tend to block or

shield electromagnetic waves The waves travel along and around the

surface of the metal by a process known as skin effect By reducing the

frequency, the electromagnetic field no longer stops at the sensor’s metal

surface, but extends beyond the surface into the surrounding space

Sen-sors with a stainless-steel face use such low-frequency alternating fields

that their detection area extends well through the metal face of the sensor

to detect metallic objects on the other side

Laboratory tests compared the survivability of plastic and metal-face

products to metal-brush abrasion and hammer impacts The tests showed

stainless versions withstood exposure levels more than 20× beyond their

plastic-face counterparts Considering stainless models cost only 25 to

30% more than plastic, they can be an economical replacement over an

extended time with no trade-off in durability versus sensing distance MD

Pepperl+Fuchs (www.pepperl-fuchs.us) supplied information for this column.

Edited by Robert Repas

RS# 128

NOVEMBER 8, 2012

“Innovation distinguishes between

a leader and a follower.”

- Steve Jobs

As the leading manufacturer of OEM pumps and compressors, our innovation in design and technology has helped our customers create new innovative products and become leaders

in their marketplace

For more information on how Thomas innovation can help you lead your industry, go to

gd-thomas.com/md11

Improving Lives through Innovation TM

RS# 129

Improving Lives through Innovation TM

2450Z SERIES BLDC PUMP

An Illustration

in Innovation

The innovative 2450Z BLDC pump is perfect for medical and other applications requiring a small lightweight pump with a high performance

to weight ratio.

• Efficient, variable speed brushless

DC motor conserves power by matching output to requirement

• Lightweight – 6.8 lbs vs 9.5 lbs with AC motor

Much has been made of Google’s self-driving cars Fitted

with AI software and an array of sensors, the

computer-controlled fleet recently surpassed 300,000 road miles

without an accident The company says robot drivers

react faster than humans and don’t get sleepy, distracted,

or intoxicated, and would boost road capacity by letting cars drive more

safely and be spaced closer together But right now, the experimental vehicles

require a human in the driver’s seat Most experts say practical autonomous

cars are years away from affordability and mass production

With less fanfare, several mining operations have been running

autono-mous haul trucks with considerable success Caterpillar is operating a few

small fleets in the U. S and abroad, and will soon have 45 unmanned

haul-ers at an iron-ore mine in Australia Komatsu has likewise deployed such

vehicles in Chile and Australia It expects to have 150 driverless trucks at a

Rio Tinto mine in Western Australia within the next four years, run from an

operations center in Perth, nearly 1,000 miles away

These “ultraclass” dump trucks — the size of a small house and carrying

payloads up to 400 tons — rely on sophisticated controllers, GPS,

obstacle-detection systems, and a wireless-communications network Software

algo-rithms tell the machines where to go and what to do, while seamlessly and

safely working with and around other equipment and personnel

It’s mining of the future, today Driven by a booming demand for

miner-als, autonomy is seen as a way to get more ore out of the ground quickly and

efficiently Trucks can be programmed to back under a shovel to within a few

inches of the same spot, all day long, to speed loading Cycle times are

al-ways the same, with no time lost from operator fatigue, rest breaks, and shift

changes And consistently operating trucks within design specs can

maxi-mize fuel economy, lessen mechanical breakdowns, and improve tire life

While up-front costs are higher, these benefits offer potential savings in

the millions, say OEMs and mine operators alike Autonomy also addresses

a growing shortage of skilled workers as mine sites move into more remote

areas It may attract a new generation of employees who have grown up with

powerful computers, video games, and the Internet and would otherwise

never consider a career in mining

Users are learning lessons as they gain experience One is that humans

intuitively sense surroundings in ways that today’s smart machines cannot

For instance, a driver who hears an unusual noise or sees a broken

compo-nent can stop the truck or call maintenance Computers can’t monitor in the

same way Condition-monitoring systems help, but safety checks are needed

at regular intervals

Another aspect is dealing with mine regulations that weren’t written with

unmanned vehicles in mind For instance, MSHA codes say cab windows

must be kept clean, and mobile equipment cannot be left unattended unless

the brakes are set Obviously, they make little sense with unmanned vehicles

Cat has had to work with local agency officials to overcome these hurdles

Granted, mining trucks aren’t dealing with the same level of complexity as

Google’s cars, but they’re actually getting work done and growing ever-more

sophisticated The ultimate goal: completely autonomous mines with not

only unmanned haulers, but drill rigs, shovels, and loaders, too Some say

that could happen within the next 5 to 20 years. MD

RS# 130 NOVEMBER 8, 2012 MACHINE DESIGN.com 35

INVENTOR’S CORNER

The Karlan Cam Engine is

running on a bench with

the “cam-case” panels

removed to show the

mechanism Ordinarily, this

would be enclosed for the

lubrication system, as it is

in the Karlan Car.

Paul Karlan is holding a disc

valve and a cam.

Edited by Leslie Gordon

Compact engine packs a powerful punch

Paul Karlan first thought up his Karlan Cam Engine for surface vehicles about

50 years ago when he was trying to figure out a different way to change the cating motion of pistons to rotary motion Instead of using a crankshaft, his engine uses two cams attached to the output shaft The engine has four cylinders, two banks of two cylinders each, parallel to the output shaft Both the opposite cylinders fire every 180º (both sides), for four cycles/rev, as opposed to a crankshaft engine, which is two cycles/rev A disc valve is keyed to the output shaft between the two cylinder banks The disc valve meters the four cycles in and out of the cylinders The pistons connect to the connecting plate which rides on the cams The cam lobes are tapered to provide true rolling motion between the cam followers and the cam The connecting plates on each side of the cylinder blocks reciprocate equal and oppo-site to each other, giving balanced motion

recipro-According to Karlan, his barrel engine is the only one with two cams and four inders The only other barrel engine he knows about — the Hermann engine — has one cam that sits in the center of the output shaft, and two banks of six cylinders on each side of the block The Hermann engine design has disadvantages, says Karlan

cyl-It uses poppet valves, which have intake/exhaust overlap The Karlan engine has a disc valve with little intake/exhaust overlap The clearance between the disc valve and the cylinder heads in the Karlan engine is just a couple of tenths This minimal clearance is maintained by “floating seals“ — i.e., the thin layer of air — so there is

no friction and almost no compression leakage This patented feature has been well tested in the running prototypes

Another advantage pertains to side pressure, says Karlan Piston side pressure on the side of the cylinder wall is what turns the output shaft on the power stroke The connecting plates on the Karlan engine reciprocate on bronze bushings with hard-surfaced, lubricated guide rods, which take all the side pressure, with little sliding friction And, there is no side pressure on the pistons True, a significant weight goes back and forth, but the momentum of the reciprocating plate goes into the flywheel, says Karlan The only energy lost is in the friction of the slides and there is little friction His special cam followers have high-speed, heavy-duty radial and thrust bearings mounted in an aluminum housing (not needle bearing cam followers) His

engine output shaft, thus, provides low rpm with high torque

In addition, the length of the connecting rod determines the sion ratio Users can, thus, adjust the compression ratio Karlan believes his engine is more efficient than current designs because it entails almost no intake/exhaust overlap and less internal sliding friction Although the work-ing prototype has not yet been tested for extended operation, Karlan says it shows no inherent weak spots, and is a sturdy mechanism

compres-The Karlan Cam engine has a low and long configuration which could apply to aircraft and more Karlan feels his engine could be an alternate to the polluting turbojet engine, which many scientists link to global warming Propulsion could be by ducted fan or gasoline electric

The engine can have pistons with small or large diameters, up to 10 in or more Karlan’s prototype engine, which is running on gasoline on a bench,

shown at http://tinyurl.com/9setjoa, has 2½-in bores The Karlan Cam Engine Car, shown at http://tinyurl.com/9gcbhnd, has 31/8-in bores.

The Karlan engine has relatively few parts It has no gears, no timing belts, no springs, and no gaskets The engine can be air or water cooled The Karlan Car was water cooled and had a pressurized lubrication system Karlan plans on applying several improvements, including a special supercharger Karlan can be reached at

NOVEMBER 8, 2012 MACHINE DESIGN.com

36

RS# 131

MOTION CONTROL

lowers is to transmit motion rather than support loads.Regardless of their purpose, rollers and followers are commonly hybrid designs with polymer load-bearing sur-faces over metal roller bearings or structural hubs These hybrid components, often sized as drop-in replacements for standard-sized all-metal components, offer compelling technical advantages due to their use of polymers:

• Self-lubricating Engineering polymers best suited for

rollers are self-lubricating, a property that last the life of the component

Bearing surfaces made from these polymers never require lubrica-tion between the roller and rail

When combined with lubed-for-

l i f e b e a r i n g s , polymer surfaces eliminate main-

t e n a n c e c o s t s associated with regular lubrica-tion, even those scheduled after

w a s h d o w n s

Engineers might only glance at the dimensions and load

capacities of roller and cam followers to ensure they will

fit in their design before placing an order But they should

pay closer attention because these components can make

or break the performance of motion subsystems critical

to a host of industrial machines

Choose the wrong roller or cam follower and your

design can be destined for a shortened life plagued with

maintenance headaches, contamination issues, and speed

limitations The wrong component can also drive up

oper-ating and manufacturing costs The right components, by

contrast, will contribute to a longer life of reliable motion

that engineers and buyers expect

But how do you pick the right roller or cam follower for

the job at hand?

The trick is considering not just sizes and loads but also

the materials that make up the roller’s bearing surface

The polymer advantage

Many engineers still believe that heavily loaded

ap-plications need metal rollers and cam followers They are

unaware that polymer bearing surfaces withstand

enor-mous forces if designed properly At Intech Power Core,

Closter, N J., for example, we’ve delivered polymer

roll-ers that withstand 8-ton loads These rollroll-ers have been

used in ski lifts and rigs that can raise an entire

build-ing But the primary task of most rollers and cam

Intech Power Core

Closter, N J.

Edited by Stephen J Mraz stephen.mraz@penton.comResources:

Intech Power Core, www.intechpower.com

For another feature on plastic parts, scan this

code or go to: http://

machinedesign.com/ article/plastic-gears- outlast-metal-0506

on metal hubs and roller bearings Using nylon eliminates the need for lubrication and makes the components quieter than their all-metal counterparts.

NOVEMBER 8, 2012 MACHINE DESIGN.com

38