507 Mechanical Movements - Brown Part 4 pps

Irregularvibratingmotionisproduced bythe rotationofthe circular disk, inwhich isfixeda crank-pin working in anendless groovecutin the vibrating arm.. tilinear motion obtained from circul

workingin aslotted yoke, thereby

dispens-ing with the oscillating connecting-rod or

pitman

94 Variable crank,twocircular plates

re-volvingonthesame center Inoneaspiral

grooveiscut; in the other aseriesof slots

radiatingfrom the center On turningone

of these plates around its center, the bolt

shown near the bottom of the figure,and

whichpassesthrough the spiralgroove and

radial slots, is caused to move toward or

fromthe center of theplates.

95 Onrotating the uprightshaft,

recipro-catingrectilinearmotion is imparted bythe

oblique disk tothe uprightrodrestingupon

itssurface

outside circle is then divided,into double

the number of these divisions, and lines

drawn to the center The curve is then

drawn through the intersectionsof the con-centric circlesand the radiating:lines.

97 This isa heart-cam,similar to 96, ex-ceptthatit isgrooved

98 Irregularvibratingmotionisproduced

bythe rotationofthe circular disk, inwhich

isfixeda crank-pin working in anendless

groovecutin the vibrating arm

99 Spiralguide attachedtothe faceof a disk; usedforthe feed-motion of adrilling

machine

102 JOS

105

108

106

109

104

107

tilinear motion obtained from circular mo-!

groove will traversethe cylinder from end

103 Rectilinearmotionofslideproduced

bythe rotationof screw.

104 In this,rotarymotion is

imparted to the wheel bythe rotationof the screw, or

rectilinear motion ofthe slide by the

rota-tion of the wheel Used in screw-cutting

and slide-lathes

105 Screw stamping-press. Rectilinear

motion from circularmotion

i

106 and 107. Uniform reciprocating

rec-tilinear motion, produced by rotarymotion

109 Therotationofthe screwatthe

left-hand side produces a uniform rectilinear

movement of a cutter which cuts another screwthread Thepitchof the screwtobe

cut may bevaried by changingthe sizesof the wheelsattheendof the frame

no Uniformcircular intouniform recti-linear motion; used in spooling-frames for

leading or guiding the thread on to the spools Therollerisdivided intotwoparts, each havingafine screw thread cutupon it,

onearightand the other a left handscrew

Thespindle parallelwiththe rollerhasarms

777 112 113

n

be obtained by this device The threads

aremade ofdifferent pitchand runin

differ-ent directions, consequently a die or nut

fitted tothe inner and smallerscrewwould

traverse only the length ofthe difference

be-tweenthe pitchesforevery revolution of the

outsidehollow screwinanut

112 Persiandrill. Thestockof the drill

hasa very quick thread cut upon it and

re-volves freely,supported by thehead at the

top,which restsagainst thebody The

but-ton or nutshownonthemiddleof thescrew

is held firmin thehand,and pulled quickly

up and down the stock,thus causing it to

revolvetothe rightand leftalternately

113 Circular into rectilinear motion, or

vice versa,bymeans ofrackand pinion.

114 Uniform circular motion into

reci-procating rectilinear motion, by means of

mutilated pinion, which drives alternately

the topand bottomrack

ofthetoothedwheels

racks beingin different planes Bothpinions

are looseon the shaft. Aratchet-wheel is faston the shaftoutsideof eachpinion,and

apawlattached tothe pinion to engage in

it,oneratchet-wheel having its teeth set in

onedirectionandtheother having itsteeth set in the opposite direction When the racks move oneway,one pinion turns the shaftbymeansof its pawl andratchet;and whenthe racks move the opposite way, the other pinionacts inthesameway,onepinion

alwaysturninglooselyonthe shaft

117 A cam acting between two

friction-rollers in a yoke. Has been used togive the movement to the valve of asteam en-gine

118 A mode of doubling the length of stroke of a piston-rod, or the throw of a

crank Apinion revolving ona spindle at-tached tothe connecting-rod orpitmanisin gear with afixed rack Anotherrackcarried

bya guide-rod above,and in gear with the opposite side ofthe pinion,is free to

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the bar carrying the oblong endless rack,

produced bythe uniform rotary motion of

the pinion working alternately above and

moves upanddownin,andisguidedby, the

slotted bar

120 Each jawis attached to one of the

two segments,oneof which has teeth

out-rideandthe otherteeth inside On turning

the shaft carrying the two pinions,one of

whichgears withoneandtheotherwith the

other segment, the jaws are brought

to-gether with greatforce.

the rackactuponthose of thetwo semi-cir-culartoothedsectors,andthe spur-gears at-tachedtothe sectors operate uponthe cen-ter gear Thetwo stopsontherackshown

by dotted lines are caught by the curved

piece on the center gear, and lead the toothed sectors alternately into gear with thedoublerack

124 Fiddle drill.

Reciprocating

recti-linear motion of the bow, the string of

whichpassesaroundthe pulleyonthe spin-dlecarrying the drill,producingalternating

rotarymotion of thedrill.

I2i Alternatingrectilinearmotionof the

rod attachedto thedisk-wheel produces an

intermittentrotarymotion of the cog-wheel

-bymeansof the clickattached to the

disk-'

wheel Thismotion, whichisreversibleby

throwingover theclick, isusedforthe feed

of planingmachines andothertools.

125 Amodification of themotionshown

122, but ofa more complexcharacter

126 Abell-cranklever,usedforchanging

thedirectionofanyforce

131

shaft carrying the three wipers produces a

reciprocating rectilinear motionof the

rec-tangularframe. Theshaft must revolvein

thedirectionofthearrowforthe partstobe

inthe positionrepresented

the sameprinciplesas themicrometer screw

every revolutionof the windlassis equal to

half the difference between the larger and

smaller circumferences of the windlass

bar-rel.

130. Shears for cutting iron plates, etc.

Thejaws are opened bythe weight of the

longarmoftheupperone,andclosedbythe

rotation ofthecam

131 On rotating the disk carrying the

crank-pin working in the slottedarm,

reci-procating rectilinear motionis imparted to

the rack at the bottom bythe vibrationof

the toothedsector

used in presses to produce the necessary

and force the lower disk down The top

diskmust befirmlysecured in a stationary position, exceptas toitsrevolution

133 A simple press motion is given

throughthehand-crankonthe pinion-shaft;

the pinion communicating motion to the toothed sector, whichacts uponthe platen,

bymeansof therodwhich connectsit there-with

134 Uniform circular motion into

recti-linearbymeansof a rope or band, which is

woundonceormore timesaroundthe drum

135 Modification of the triangular eccen-tric 91, used on the steam engine in the Paris Mint Thecirculardiskbehind car-ries the triangular tappet,which

communi-cates an alternate rectilinear motionto the valve-rod Thevalveisatrest at the

com-pletionofeachstrokeforan instant, andis

pushed quickly across the steam-ports to the endof thenext

isshown hasitsrim formedinto teeth,or

139