creative assemblies

7/27/2019 creative assemblies

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I L L U S T R A T E D S O U R C E B O O K of M E C H A N I C A L C O M P O N E N T S

S E C T I O N 27CREATIVE10 Ways to Amplify Mechan ical Movements 27-210 Ways to Amplify Mechanical Action 27-4How to Damp Axial and Rotational Motion 27-68 Snap-Action Devices 27-8Make Diaphragm s Work for You 27-10Control-Locks Thw art Vibration and Shock 27-12liq uid leve l Mechanisms, Indicators and Controllers 27- 14Liquid Level Indicators and Controllers 27- 16Hangers Put Up by Hand 27- 18Assemble Sheetmetal with Sheetmetal 27-20Devices for Indexing or Holding M echanical Movements 27-21Slash Errors with Sensitive Balance 27-22Rotary Piston Engine 27-23


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27-2

10 Ways to AmplifyMechanical MovementsHow levers, membranes, cams, and gears are arranged tomeasure, weigh, gage, adjust, and govern.Federico Strasser

HIGH AMPLIFICATION fo rsimple measuring instrumentsis provided by double leveracfion. Acc uracy can be as hig hab 0.0001 in.

Bridgelever-Spring

ULTRA-HIGH AMPLIFICA-TION, with only one lever, isprovided in the Hirth-Mini-meter shown here. Again, t hcrange is sii inl l .

PIVOTED LEVERS allow ex -tremely sensitive act ion in com-pardtof-type memuring deviceshown here. The range, how-ever, i s sniall.

Co r n t o l l o we r 7 Aujusftng corn-

COR CLOSE ADJUSTMENT,c l e c t r i c i l n ie : i s i i r i n g i ns t rn -tiicnts emploj eccentric c i in i \ .l le rc niovenient i s r cduc r t l , nut;iniplified.

A@bsfing Section through A - A-Worm qeur

MICROSCOPIC ADJUST-MENT i s achieved liere 112 em -ploying ;I large eccentric-c;iiitcotipled (( I :I worni-gear drive.Snioolli, f i i i e udjus lnien l result.


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Creative Assemblies 27-3

/ever or beumSfeelyord rod-

LEVER - ACTUATED \+eigh-scale needs no springs t o niaici-Vain balance. The lever system,mounted on knife edges, is ex-tremely sensitive.

gear m dp/nfon

QUADRANT-GEAR ANDPINION couplctt to an l , - le\crprovidc wi ip le mot rnir i i t of in-dicirttrr needle for snisll chiu~gcsin go\rrnor speed.

f

CAPSULE UNIT fo r gas-pressure indicators should beprovided with a compressionspring to preload the membranefor more positive action.

6MPLIFIED MEMBRANEMOVEMENT can be gained bythe arrangement shown here. Asmall chain-driven gear linksthe lever system.

GEARED quadrant ar e I J W ~herc t o give flie coniI)artatoriiiaxiniuni sensitivity coinhitiedwith ruggedness.


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27-4

10 Ways to Amdi fvIMechahical ActibnLevers, wires, hair, and metal bands are arranged togive high velocity ratios for adjusting and measuring.Federico Strasser

Iu s

DfAL INDICATOR startswith rack and pinion am-plified by gear train. Thereturn-spring takes outbacklash.

Geared lever

LEVER AND GEARtrain amplify the micro-scope control-knob move-ment. Knife edges providefrictionless pivots for lever.

Springcen er fines

Moveme

Curvedlever

3 ZElSS COMPARATOR isprovided with a special le-ver to move the stylus clearof the work. A steel ballgreatly reduces friction.CURVED LEVER is soshaped and pivoted thatthe force exerted on thestylus rod, and thus styluspressure, remains constant.spring ba l l Ormeasuring face

5HOT-WIRE AMMETERrelies on the thermal ex -pansion of a current-cany-ing wire. A relatively largeneedle movement occurs.


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Sfeel

METAL BAND is twistedand supported at each end.Small movement of contactsphere produces large nee-dle movement.

STEEL RIBBONS trans-mit movement without theslighte st backlash. T hemovement is amplified bydifferences in diameter.

HYGROMETER actua-ted by a hair. When hu-midity causes expansion ofthe hair, its movement isamplified by a lever.

ACCURACY of YU'squarescan be checked with a de-vice shown here. The rodmakes the error muchmore apparent.

Suppoff + --+ ,hticromeferbushing meosures\ movementof b i nresponse fomovement

TORSIONAL deflection ofthe short arm is transmittedwith low friction to thelonger arm for micrometermeasurement.


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27-6

How to Damp Axialand Rotational MotionFluid-friction devices include two hydraulic and tw o pneumatic actions;swinging-vane arrangements dissipate energy and govern speed.Frederico Strasser

CI ADJUSTABLE BYPASS between thetwo sides o f the piston controls speed atwhich fluid can flow when piston is moved.

CHECK VALVE in piston lets speed becontrolled so that the piston moves fasterin one direction than in the other.

Sori& -gr ipa t achmenf

ROTATING VANES are resisted by theair a9 they revolve. Make allowance forsudden stops by providing a spring.

SWlNGlNG VANES create increasedwind drag as centrifugal force opens themto a larger radius.


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PNEUMATIC CHECK VALVE acts inmanner similar to that of previous device.Vertical position, of course, is necessary.

Sfa ionory pos i t ion- .' ILJ

VANE AREA INCREASES when thespring-loaded vanes swing out. Forces dif-fer fo r niotion into or against the wind.

screw

AFLEXIBLE DIAPHRAGM controls shortmovements. Speed is fast in one direction,but greatly slowed in return direction.

Copper or Closed- circ uitaluminum disk cur renfs es fob lkhtheir own magneticR f ie ld -

Magnet UI

EDDY CURRENTS are induced in diskwhen it is moved through a magnetic field.Braking is directly proportiona1 to speed.


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27-8

8 Snap-Action DevicesA further selection of basic arrangements for obtainingsudden motion after gradual buildup of force.Peter C. Noy

Acfuofing forcePreload force

1Torsion ribbon . . .bent as shown wil l turn "inside out" at A with a snap actionwhen twisted at 6. Design factors are ribbon width a nd thick-ness, and bend ongle.

Resef

2Col laps ing cylinder . . .has elastic walls that may b e deformed gradually untiltheir stress changes from compressive to bending with th eresultant collapse of the cylinder

3 Adjus mentY4owed spring . . .will collapse into new shape when loaded as shown."Push-pull" type of steel measuring tape illustrates thisaction; the curved material stiffens the tape so that itcan be held ou t as a cantilever until excessive weightcauses it to collapse suddenly.

Flap vane . . .is for air or liquid flow cutoff at a limiting velocity. With a regulatingvalve, vane will snap shut (because of increased velocity) when pressureis ieduced below a certain value.


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Fusible l i n k

Closed container,

5Sacrificing link . . .IS used generally where high heat or chem-ically corrosivc conditions would be hazardous-if temperature becomes too high, or atmos-phere too corrosive, l i nk will yield at whateverconditions it i s designed for. Usually the deviceis required to act only once, although a devicelike the lower one i s quickly reset but restrictedto temperature control.


6Gravity-tips . . .aithough slower acting than most snap mechanisms, cant.r called snap mechanisms because they require an accu-mulation of energy to trigger an automatic release. Tipping-troughs used to spread sewage exemplify arrangement shownin A, once overbalanced, action i s fast.

re

B

8W Overcentering leaf-spring . . .

action i s also the basis for many ingenioussnap-action switches used for electrical control.Sometimes spring action is combined with thethermostatic action o f a bimetal strip to makethe switch respond to heat or cold either for con-trol purposes or as a safety fea ture.

7Overcentering tension . . .spring combined with pivoted contact-strip is one arrangementamong many similar ones used in switches. Arrangem ent shownhere i s somewhat unusual, since the actuating force bears onthe spring itself.


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27-10

Mak e Diaphragms Work for YouDiaphragms have more uses than you think. Heres a display of applications thatsimple fabric-elastomer diaphragms can handle economically and with a minimumof design problemsJohn F. Taplin

O i lconnecf i

A / nospher i c ressure

P ressu re possoge

Expansion compensator for liquid-filledsystems handles thermal expansion of2 the liquid as well as any system losses.

RubberS O ldust

A force-balance load cell converts theweight or force of any object into an6 accurate reading at a remote point.

l n le f

A balanced valve uses a fabric-elasto me rdiaphragm to hydrostatically balance the3 valve poppet as well as the valve head.

-Diaphragm

Spring

Linear actuator converts gas or f luidpressure into a l inear stroke without7 leakage or break-out fr ict ion effects.


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,Diuphragms

.Piston

Double-acting actuator provides forthrust in either direction by placingtwo diap hragm assemblies back to back.

Diapn raynm

Reg ulating valve c ontrols the value ot airpressure by means of a diaphragm-bal-4 anced valve and tw o control diaphragms.

Diaphragm'u+-S h a f tShaft seal uses lubricant pressure toforce the sidewall of the diaphragm to8 rol l against the shaft and housing.

Double-act ing pump has two diaphragmsto give smooth and continuous f low of f lu id5 o equipment at a safe working pressure.

Damping mechanism p revents abrupt orsudden motion in a machine. Damping9 amount is controlled by orifice size.


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27-12

Control-Locked ThwartVibration and ShockCritical adjustments stay put-safe against accidental turningor deliberate fiddling with them.Frank William Wood JR.

wlamp knoba..SPLIT YOKE clamps on shaft wheneccentric squeezes ends of yoke together.Knurled knob is handy for constant use, andeliminates need f o r tool. Another advantageis high torque capacity. But this design needsconsiderable space on panel.

2 FINGER springs into place between gearte h at turn of cam. Although gear lock isideally suited for right-angle drives, sizeof teeth limits positioning accuracy.

Knurled Split I3,. PLIT BUSHING tightens on controlshaft, because knurled knob has taperedthread. Bushing also mounts control topanel, so requires just one hole. Lever, likeknob, does away with tools, bu t locks tigh terand faster. For controls adjusted infre-quently, hex nut turns a fault into an ad-vantage. Although it takes a wrench to turnthe nut, added difficulty guards aga inst knob-twisters.

' Control shaft Hex nut-


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4 . . CONSTANT D R A G of tapered collar onshaft makes control stiff, so it doesnt needlocking and unlocking. Compressed lip bothseals out dust and keeps molded locking nutfrom rotating.


5 . . O N G U E slides in groove, clamps downon edge of dial. If clamp is not tight, it canscratch the face.

6 , . SPOT-BRAKE clampis self-locking, whichmeans it takes two handsto make an adjustment,one to hold the clamp openand one to t u rn the dial.


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27- 14

Li uid level Mechanisms -In3 cators and ControllersMeans o f determining liquid level,

detection of changes in liquid level,transmission of indicated levels. o rwarnings of cha nges heyond set limits;and means of using level changes forlevel control, or control of other con-ditions such a5 temperature and pres-sure, have been accomplished by numer-ous mechanisms. The most pcpular

& Ffoaf chamber

devices employ floats or pressure meas-urement with instruments such as theU-tube manameter, bourdon tube, andbellows.

The methods shown here are largelyindicating methods or simple devices forautomatic control of liquid level al-though they can conceivably be appliedto control other conditions such as tem-

perature an d pressure. Methods usingelectric resistance of a column of liquidand measurement of pressure changesby means of piezo-electric crystals arenot shown. Patent No . 2,162,180 de -scribes a method involving determina-tion of change in air pressure when ameasured volume nf ai r is introducedinto a tank.

Fig.1-Flo at and Lever- Operated Pilot Valve

Sfof fo r f i o a tcounterweigh annSfop or f/oaf ,movemen f--'--

fed or dece/eratedmovements ofplungerfo r an y floaf movemen UFig.2-Float and Cam-Operated Pilot ValveBourdon tube sqpporfsmagnefic core in re-sista7ce coils

~ i Y (Magnefic coreflfi v v _ . - : i t m a v b e ~ u d -

/ndicafor orrecorder--- -

I/ouf---,

IM II < i - - - - r

pokted C;i;-'ob y float inmercuryI/ - ube)4 i r econnecfionfo gafvano-meter inreceiver

Fig.4-Float and Pulley Indicator Fig.5-Pressure Dome Indicator-


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Sec+/ona/ view excepffo r weigbfs and ffoafFig. 6 - F l o a t Control o f Discharge

Tape visible Vapor- ighcovers --/hroughwindow

Tank floor, At-Pu//ey frome supporfFig. 8-Tank Roof Indicator

._-__---------- .-.-.-.--ig.7-U-Tube Manometer with Water Columns

Double bdancing mechanism fUfs mercuryswifcbes for u/arms when ref r i eranf i sbe/ow eif her operufing or dle &e/s

- Grooves

:---F/oafing frigerun sdmpling reservoirFig.10 -Refrigerant Balance

Back F r o n tFig.9-Dip StickIndica tor

liquid >eve/ 5.50indicufed b y/tgh reflecffonfrom menrsrus

Fig.11-AutomaticBatt ery Filler


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27-16

Liquid Level Indicators andControllersThirteen different systems of operation are shown. Each one represents at least onecommercial instrument. Some of them are available in several modified forms.

Iml

The Bristol Co.

Bubbler f ixtu re&Air supply

Either m ethod can

DXAPHRAQM ACTUATED INDICATOR. Can be used with BUBBLER TYPE RECORDER measures height E. ca nany kind of liquid, wheth er it be flowing, turbulent, or be used with a11 kinds of liquids, including those carry-carry ing solid matter. Recorder can be mounted above or ing solids. Small amount of air is bled into submergedbelnw the level of the tank or reservoir. pipe. Gage measures pressure of ai r that displaces fluid.

BELLOWS ACTUATED INDICATOR. Two bellows andconnecting tubing are fllled with incompressible fluid. Changein liquid level 'displaces transmitting bellows and pointer.

I I i L/,51 Use t e r m i n o l 5 fo rpumpdown,terminal 3 for ourno-uo control

f

ELECTRICAL TY PE LEVE L CONTROLLER. Positionsof probes determine duration of pump operation. Whenliquid touches upper probe, relay operates and puinpstops. Through auxil iary contacts, lower pmbe Pro-vides relay holding cdrrent until liquid drops below It.

op-ociing swi tch

To float inion&Minneapolis -HoneywellFLOAT-SWITCH TYPE CONTROL-LEX. When liquid reaches predeter-mined level, float actuates switchthrough horseshoe-shape arm. Switchcan operat e valve or pump, as required.

c ,/------

_ _ _ - -AUTOMOTIVE TYPE LIQUID LEVEL INDICATOR. Indicator and tank U n i t areconnected by a single wire. As liquid level in tank increases, brush contact ontank rheostat moves to the rlght, introducing an increasing amount of resistanceinto circuit that grounds the "F" coil. Displacement of needle from empty markIs proportional to the amount of resistance introduced into this circuit.


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Recorder

Counterweigh

' r o p ey o o t

f l o a t chamber

Minmaplis Mney we l lFLOAT TYPE RECORDER. MAGNETIC LIQUID LEVEL CONTROLLER. DIFFE RENT IAL PRE SSU RE SYSTEM.Pointer can be at twhed to a When liquid level is normal, common-to-right Applicable to liquids und er pressure.calibrated float tape to give Measuring element is mercury manometer.an approximate hstantane- level drops to predetermined level. magnetic Mechanical or electric meter body can beous indication of fluld level. Piston is drawn below the magnetic field. used. Seal pots protect meter body.

leg circuit of mercury switch is closed. When

t o f ocfuo f ing, Pressure gougee-7 element ,-_PASeof requi red fwcor ros ive orv iscous f lu iUs

M i m q o o f i s -HmRywrllDIRECT READING FLOAT TYPE GAGE. Inexpensive,direct-reading gage ha s dial calibruted to tan k volume.Comparable type as fa r as simplicity Is concerned hasneedle connected through a right-angle a rm to float. Asliquid level drops, float rotates the arm and the needle.

PRESSURE UAUE INDICATOR for open vessels. Pressureof liquid head is imposed directly upon a ctua ting element ofpressure gage. Center line of the actuating element mustconincide wlth the minimum level line if the gage is to readzero when t h e liquid reaches t h e minlhum level.

Heoter w i r e -

Bimetal s t r i p ----

7,BIMETALLIC TYPE INDICATOR. When tank is empty, contacts in tank unitju st touch. With switch closed, heaters cause both bimetallic strips to bend. Thisopens cont acts in tank an d bimetals cool, closing circuit again. Cycle repeats abou tonce per se a As Hqutd level increases. float forces cam to bend tank bimetal. Actionis simllar to previous case, but current and needle displacement are increased.

rank

-Float

SWITCH ACTUATED LEV EL CON-TROLLER. Pump is actuated byswitch. Floa t pivots magnet 40 thatupper pole attracts switch contact.Tank wall serves as other contact.


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27-18

Hangers Put Up by HandNo tools needed to install these hangers made of wire, rod or bar-stock.L. Kasper

CLIP is most secure when tubing of right sizehelps keep it spread. To install, hook one sideover edge of slot and spring in other side.EDGE HANGER doesnt have to be sprung,but requires enough clearance above holes sothat ends can be pushed down through.

RAMPS cam split end together as hanger ispushed into slot. Ends spread again whennotches engage sheet.

Small end enters large slot first, then tilts overinto smaller, close-fitting slot.


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Creative Assemblies 27- 19

LOOP hooks over bar and is held secure byshort tail which snaps into hole drilledthrough the side.

COIL grips edges of T- or I-section or flatbar. Spreading the ends wraps wire tightlyaround tubing to prevent vibration.

DOUBLE HANGER supports two tubes 8sthey pass through divider. While tubes are inplace hanger cant come out.

8ND PIECE supports pipe between waUs ofany thickness. First spring it over pipe, thenslide it along pipe into holes.


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27-20

Assemble Sheetmetal w it hSheetmetalThese sheetmetal parts join sheetmetal quickly with the simplest of tools.L. Kasper

SQUEEZE CLIP holds two overlappingsheets together. The ends of the clip arepushed through parallel slots, then bentover much like a staple.

ALIGNING PIECE slides up ou t of theway in long slot while butting sheets arebeing positioned. Afterwards it slips downover lower sheet.

CUP carries a bar on both sides of divider.Here bars stick up above th e top, butdeeper cutout will lower them until theyare flush or sunk.

ESS supports shelf between uprights, Bymating with notched edge it acts as a keyt o keep shelf from sliding back and orth.an d provides positive location,


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Creat ive Assemblies 27-21

Devices for Indexing or HoldingMechanical MovementsLouis Dodger

v

detent /

AXIAL POSITIONING(INDEXINS) BY MEANS OFSPACED HOLES IN INDEX BASE

! l .

ROLLER DETENT POSITIONS IN A NOTCH:N t a n a 1 co sRISE, S z=-2 COSa

ROLLER RADIUS, R =( i v y , .)( C O S a )- 1 -cOSa

\Refoihihg Puf/ h o bDi n to release

RADIALLY ARRANGED DETENT HOLDS INSLOTTED INDEX BASE


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27-22

Slashes Errors with Sensitive Balance

SENSITIVITY OF BALANCE isindependent of temperature fluctua-tions. To keep the center of gravityconstant, two temperature-sensitiveelements are riveted to aluminum-alloy balance beam, bridging a slotwhich is directly over the balancepoint. Their coefficient of expansioncompensates for beam deflectioncaused by variations in temperature.

Enclosed in a cylindrical canisterat the rear of the balance beam is avane that damps its movement, pre-venting oscillation. The hanger atthe front of the scale carries sets ofring weights which are lifted by cam-operated levers. The shafts on whichthe cams are mounted are connectedto the mechanical readout.The scale in effect weighs by sub-

traction since it is balanced, whenempty, by all the ring weights restingon the hanger. To weigh a n unknown,the ring weights are lifted from thehanger. The sum of the raised weightsis shown on the mechanical counter,which displays the first three digits.The complete total is displayed by themechanical plus the optical systemthat projects through the reticle.


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Rotary Piston EngineWarren Ogren, InventorRobert Parrnley, Draftsman

Exploded drawing of engineillustrates the many standardmechanical components thatare arranged to preform afunction in a new way.


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27-24

End View ofRotary Pis ton Engi

Figure 2

125 \i

FIG. 31I

7

c u 9>-Aw ay View of Rotary Pis ton Engin e

creative assemblies

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