US2472658A - Rack and pawl actuated quickacting clamp - Google Patents

Description

June 7, 1949. C. L. GILBERT 2,472,658

RACK AND PAWL ACTUATED`QUICK-ACTING CLAMP Filed Aug. 17, 1945 2 Sheets-Sheet 1 June 7; 1949. Q ILBERT y 2,472,658

RACK AND PAWL ACTUATED QUICK-ACTING CLAMP Filed Aug. 17, 1945 2 Sheets-Sheet 2 Z//libllmu www L A ,5 ,7, lv

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35// 33 j mm1@ 'Z725 Z3/ 1| i lim l 7' /0 Patented June 7, 1949 RAGE-AND PAWL AOTUATEDiQUICEf ACTING CLAMP Clyde-'Ll Gilbert, Elkhart; Ifldp Application August'l', 1945, Sri'l NouGIILSZl`-` .-Clams.. Cl. 144--305-)- This .t inventiomrelatesatoua; handrclamp; f

The chief obgi'ectr:oithisrzinventiorrlis toafpro.- vide a quick acting; oneehanttoperable; positive lockingfzG-clamqoa.:

The:y chief'y feature: of@ th'e :inlventom resides :in the simplicity of constructompositiveness,ofrop eration; anradinsliabilityo'theaclanfiptl The inventionisfcharacterizectfby at @shaped body, providdu ati its.'-.midiiportion withzaanger gripvsocketpan operatingilever that vlocksxf over'- center-z in ljuataposijion.m to'rthe "grip",r` ai cam 1 op:- erablefl paw-l; au clampinrgf: head#l supporting:` rack rapidilymovable `Atowardandl"away ifronr=an= anvil por-tioni` of'th'e b'ods'fffandl b'y gravitygand" cam pawls movable intowork looki'ngepositi'on",` together with-`A a" work" engaging head," cushiomv supported for rack impact shock alosorptorft;A andmicro'- metrioally-adjustablefrelativeito: theiraclc.

The 'fuili 'naturefothefinvention iwill loe Eunder'- stoodfromlthe' accompanying drawingsand'the following'-descriptirmv and claims:A4

Inf thei drawings,

Fig. 1 is a side elevation 'of f embodiment' of the invention with `partsIwork'eng-agingv posi'- ti'on; oneecornnation 'cover andlfame --p1ate"-be ing removedfforiclearness;

Fig; 2isf a rear'felevationofsuch embodiment, the-"actuating'part 'being'fb'roken -aawayfandf-shown insection to better-illustrate tHe-cover andffr'ame plate-structuree Fig-.f 3Y-is`- any enlarged lcentra-I Vsectional view of the Head-'end offthevsupporting rack; the-'Work enga-ging* head,l and* thefuniversal, resilient vand adjustableYconnection-therebetween.

Fig: 4 is aviewl'similarltofl'gt L lb'ut of ther-rack, pawl; operating leverandimmediatly'associated parts only and in the released, orc-'quickl action position;

Fig: Sis a vi'ewsimilarftofli'ga Ll-fwith parts shownr irraf position internlediatel'ietvveenk those illustratedin igss land 4i- In' the drawingf I=0 indicates 1 as conventionally termed Gshaped* body@ portion"- terminating at one"end"in the '-anviflfportlorr Ix Ii This-body por'- tionisreeniorced 'by-af cential ri-Eorv-n I'Zi'which adjacent"tlie'midiportionof the lbody isfvenlarged asat" I3"and^'apertured at- III' tiformfformfwnger grip" or s ocket;

The upper end I5 of the body I0 does noti-extend-forwardly'asf-far asetheeanvillportiou`v I Ibut terminatesfshort thereof asiat If. Extending upwardly therefrom-lis `a"hase'sec-tion ITI-'fwhicli--is shouldered*longitudinally asiat-| I 8i Annuaire oiconrp'lementaryf combination cover andzfra-mei fom-linggfplates; Ifhave-inwardly'vfdirected' rear endziiangesaZIlwhfch. ahutfat 12 Ii Opposite-a'thereto are'A the inwardly f directed f front enddianges-Z 2^; Theflowerzport'rons `of :said plates straddlef thegprojectingmortionfor;basefI I= fandtall axxesuita'laly1 secured: together-'hm screws,A rivetssor the ikei2'3'@ Theerear. ilangesi Zufarexcut away;t as-:at 24..-to accommcdaiiecthe:rlo'ase; |112, Base:y I"I-f extends-up;- wardlyfandr.forwardlwsaszat i25nand includes: face 26a parallel.l-` tof'flangess:z'forming: :therewith and pl'atesl Siaz'rectangularisoclcetla;

Slidable longitudinailwn the;soclcet,21-v and along tli'etangesf. 22'iis erstem 28 ;f rectangu'lamfin transversepf section and having rack'.;L teeth1 29 formed: in: facea30toppositei thez'facethat slides on: angesl Two pirxslv 3 I andl 32;'extend across va the: 1 plates I9 and constitute xed bearings'.:andmayzfbe: of rivet;E charactem ton secure ther: plates: together. slid-ably andzpivotallmmonnted onzfpin-zrcis, vthe campawl133ihaving the.elongated.'51017.34y therein, whichIrides.pinfZz'H Thaforwardfzendderminates -in the rack: engagingtteeth'ii 5t offwhic'h therel are three;-Whioliterminateiiniarcuately arranged tips. Two teth': always carry thefloadi due 1 to such arcuity:

'Ihe@oppositeendisfreducedi atl 36%to @forniva -projectionf seatableifin coil sprinfgfl' I bearingl on shoulder 382; Thlisffprog'ection"and; a portionof the body 33 is recessed at 39 and slidabler'therein is'fsterntz llllfwh'ich;y sp'aeed ffromf'fpawl-'if 33'; carries headfIII against whiolilthe otherxend-of said Sprit-ig'l 31W bears: Stem 401W exister-rds. through :the springc andi head' 4 IIiisi-1l curved.'` on: its rear 'face assat42.torbearluponanges The latter 'I include :thev central;y elongatedfl slot 431 therein, inw whichfrrides: extension 44 yof I the ystem dlandfheadf'll Springlf therefore; nor= Ina/? constrainsfpawly 33H toward-f racklengagementi. Since :therpawl ridesf` statici-ilary" pin 32 through elongated: slot'y 311;-1 azleafspringi has/its forward i bend i end .v 46 bearing: upwardly against the lowerv face of pawl'f 33 adjacent teeth-35 thereof.- AscrewLlIfI orv the-like suitably y anchors the'fopposite endffot'sai'dispringfll!toibasef II,l as i1litstratedaV Hence, spring-:45normallyrconstrains pawl' I33fupward1yrat itsforwardlend lor,' in effect, -towardicloclw/iserf rotation'ondpivot 32;.:

Pivotally y'mounted"onf the lotlierf pivot y3iI`= is'- a cam levert-48*Whichzmounts hardened sl'e'evefds. This' leveri -h'a'sfa@ attforwardc face. 50i that L just clears rack teeth 29 when .tlief'rl'everiistilted-"into f 'lockingandfholdinguposition. otherffwords,

face 58 is opposed to ilanges 22 and forms therewith and plates I9 a second and elongated socket 21a in registration with socket 21 aforesaid, so that canting of said rack is prevented.

The lever, adjacent face 59, is arcuately formed as at I, the radius of same being the distance approximately equal to that between the axis of pivot 3l and the faces of teeth 29. Lever 48 includes elongated handle 52 that initially extends rearwardly and downwardly and then extends downwardly and forwardly as at 52a to conform to the linger grip portion I3 when the lever 48 is tilted clockwise and locked over-center in holding position.

Lever 4B, below pivot 3l, includes two spaced and opposed faces 53 and 54 on its lower face and therebetween is intermediate cam portion 55. Extending upwardly as at 56 from the upper confronting face of the pawl 33 is the abutment providinT opposite faces '51 and 58 and the centrally relieved intermediate face 59 relieved as at 6U.

Fig. 1 illustrates the several parts in clamping and locked relation relative to work W. In this position the tail portion 52a is immediately contiguous to guard I3 and shoulder or face 54 of lever 48 is in engagement with shoulder or face 58 of pawl 33 and holds same forwardly while cam 55 engages face 59 of the pawl to hold the pawl against spring 45 and hence hold the rack down, so that head 60h lclamps work W between it and anvil II for teeth 29 and 35 are engaged.

When handle 52 is elevated, see Fig. 4, shoulder or face 53 is engaged with shoulder or face 51 and the pawl 33 is retracted rearwardly against spring 31. Pin 32 limits this movement. Teeth are now free of the rack teeth 29 and the rack 28 and head 60b with the interconnection therebetween may be freely slid toward and away from anvil II. Spring now holds pawl 33 elevated.

When clamping is desired, the clamp may be held in one hand with parts positioned as shown in Fig. 4 and inverted until the rack is fully retracted. The other hand then presents the work W to the clamp, the work bearing on anvil I I and the rack 28 dropping head 60h into work engagement when the clamp is positioned as shown in Fig. 4. Then handle 52 is depressed which depresses pawl 33 against spring 45 and subject to the stop function of shoulder 53 engaged with shoulder 51, the teeth 35 loosely mesh with rack teeth 29.

Continued clockwise rotation of lever 48 by further depression of handle 52 removes pawl 33 from the aforesaid stop limitation and cam now passes from depression 6I) to face 59 and forces the pawl 33 counterclockwise from the position shown in Fig. 4 toward the position shown in Fig. l. As this occurs shoulder 54 approaches shoulder 5S. Final lever movement forces head Sill) down on the work with the desired pressure and lever 48 locks over-center, as it were, such center being approximately that defined by a plane through the axes of pivots 3| and 32.

Actual clamping pressure is initially exerted when cam 55 starts to leave depression 60. Maximum clamping pressure is attained when cam 5'5 engages face 59. Thereafter lever movement is solely for locking over-center and positioning shoulder 54 immediately behind shoulder 58 to prevent accidental release of the cam lock on the rack and to retain the clamping pressure. The rack throw, by reason of cam 55 is approximately the width of two teeth.

Reference will now be had more particularly to Figs. l and 3. The head h is slightly concaved or dished as at 60a. It includes a partially spherical socket BI closed by collar portion 62 and therein is ball 63 having stem 64 extending from the collar. Stem 64 is carried by portion S5 that is slidable in socket 56 of member 61 having shank 58 reduced externally as at 69 and threaded as at 19. The lower end of rack 28 is apertured at 1I and threaded as at 12. By this means the shank 68 and head 60h can be advanced or retracted relative to the rack 28.

In Fig. 3 the adjustment is exhausted upwardly and available downwardly to the maximum degree. Fig. l shows slight downward adjustment.

For cushioning impact member E5 includes stem 13 and both are tapped and threaded as at 14. Shank G8 is recessed as at 15, same constituting a reduced extension of socket and providing shoulder 1B therebetween. Shank 63 includes apertured 'partition 11 apertured at 18 and recessed at 19 to take head 80 of the boli"I having the .threaded body portion 8| threaded into tapped portion 14. A coil spring 82 envelops the bolt and sleeve extension 13 and bears at one end on face 83 of portion IB5 and at its opposite end on partition 11.

When the head is dropped member =65 telescopes into socket 55 and is cushioned lby spring 82. This can fully collapse into bore 15 when face 83 engages face 16 when clamping pressure is applied to the rack 28. If the rack clamping movement, following such collapse, be insuiicient to properly hold the work W, the externally knurled portion B1 is rotated to adjust the head `60h relative to rack 28 so that proper pawl clamping pressure is obtained when lever handle 52 is tilted clockwise.

Having thus described the respective parts and briefly outlined the major features of operation thereof, it is now further pointed out that invention, as illustrated, by reason of the slidable extension on the toothed pawl or detent limits the clockwise rotation thereof about the axis of the pin and slot connection by reason of the lower end of the elongated slot 43 formed in the two rear flanges of the plate I9.

The lever pivot with its axis and the pawl or detent pin axis determines, as aforesaid, a plane and when the lever is sufficiently tilted clockwise it vpasses over center, as it were, and is self-sustaining in the over center position. When fully moved to the over center position the detent is locked, as aforesaid, against rack release and at the same time the free end of the lever is juxtapositioned or closely associated with the ringer grip portion I3 of the clamp body and preferably the end of that lever has slight clearance relative to the lateral projection of the lowermost portion of the body I 2.

If it be assumed that the pawl or detent incident to the cam actuation forces the rack and the head toward the work for a predetermined amount of travel in the clamping direction, then the cushion spring of the cushion connection is of such character that when it is collapsed suiliciently for the two stop shoulders 16-83 to contact, the cushion travel, as it were, constitutes only about als of an inch or approximately 7/ of the pawl responsive rack travel, same being approximately 1/4 of an inch, by way of example only.

It will be obvious .that any desired pressure application can be imparted by the head 50D for clamping the work between the head and the anvil portion, if within the range of pressure deeee-agees terminaiole by the leveragel and the cam,l etofviously, itgreatpressure is desiredV and'orilyyli'mited rack travel-is ava-ilablronly; lightf-pressure will be obtained. Consequently; the threadedad-s justmentconnection 8-I'!1t` aforesaid between the clamping head and thel rackfmemb'eri can be adjusted so thatthe desired-i clampingf'pressure will ber obtained-fertile operative andfeniective travel of the rackmember, the; detentta'n'd'lthe cam lever, andsuch-v adjustmenty for yincreased pressure is 'obtained -by-unthreading thefthireaded connection to the desired degree and a decrease in pressure is obtainable by threading yoperation to the desired degree.

The dished type head insures peripheral or circular contact with the work as distinguished from point or axial conta-ct with the work. The ball and socket connection permits :angular adjustment of the head to lconform to any flat surface and also permits positive engagement with any other surface having a curvature of greater radius than that of the concavity in the head and permits point bearing contact, as it were, with any surface that has a curvature of greater arcuity than that of the concavity of the head.

It will be further noted that the invention her-em disclosed exerts a uniform, straight and even pressure without any twisting eiect, etc., upon the work. Also, the nger hole arrangement in the body of the clamp has the further feature that the clamp body vSpaces the fingers from the work and this is particularly advantageous when a piece of hot work is to be held by a clamp for welding or like purposes or a hot tool is to be associated with work held by the clamp. Body I0 here also serves as a shield.

The invention has the further advantage that if the smallest size clamp has its body portion provided with maximum sized finger grip and it is desired to utilize standard parts for this size, the -only requisite changes will be to substitute for the body illustrated a body having a larger throat, as it were, or a smaller throat and provide a rack of greater or less length, respectively, all other parts remaining the same.

It will be further noted that the offsetting in the body portion at the end opposite the anvil end and the oisetting in the plates I9 permits the positioning of the head when fully retracted in a nested arrangement so that substantially the body full opening is available for work reception and all without enclosing the knurled adjustable member for it, in this position, is exposed at three sides and can be finger adjusted for pressure variation as previously described.

While the invention has been illustrated and described in great detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character.

The invention claimed is:

l. In a clamp structure having van anvil and a work clamping head movable toward and away from same, the combination of a reciprocable rack toothed member supporting the head, a lever pivotally mounted in spaced relation to the member, a multiple-toothed member movable toward and away from the rack toothed member for tooth engagement and disengagement, lever operable cam means for moving the second mentioned toothed member toward the anvil for effecting rack member and head movement toward the anvil for work clamping purpose, said lever operable cam means and said multipletoothed member each having a pair of spaced optoothed mem-bentowardrackf-z engagenrent. lever operationfretracting the multiple-toothed mem ber in opposition to the constraining means, at least two teethA otthemultiple-toothed member having engagement :with they racletoothed :member when the latter exerts pressure-upon the head.

2. In a'clamp"'structure"having 'an' anvil and a worlc-ciamping head movableftoward andraway from. same, the combination: of a reciproeable rack toothed member supporting the head, a lever pivotally mounted in spaced relation to the member, a multiple-toothed member movable toward and away from the rack toothed member for tooth engagement and disengagement, lever 0perable cam means for moving the second mentioned toothed member toward the anvil for effecting rack member and head movement toward the anvil for work clamping purpose, mounting means of a pin and elongated slot type for the multipletoothed member, the slot of said means being directed generally longitudinally with respeci'I to the multiple-toothed member, and yielding means normally constraining the multipletoothed member away from the anvil, and in opposition t0 the cam means operation thereof.

3. A clamp structure as defined by claim 2 wherein the multiple-toothed member has pivotal movement about; the pin axis of said mounting means, a tail slidable longitudinally with respect to the multiple-toothed member, guide mechanism of pin and elongated slot type and associated with that tail, and yielding means interposed between the multiple toothed member and the guide mechanism constraining that member and tail toward extended position.

4. In a hand clamp having a clamping head supporting rack, and a multiple-toothed member movable toward and away from Same for engagement and disengagement therewith, the combination of a cam provided lever pivotally mounted in juxtaposition to said member and having a cam portion arranged upon lever actuation to engage and move said member, rack and head into the clamping direction, and shoulder means on the lever and member adjacent the cam engaged portion of the member for predetermined engagement upon predetermined positioning of the lever, the lever, when the shoulder means is engaged, having a self-sustaining over-center position, the shoulder means on the lever and the member being disposed at opposite sides of the cam portion and cam engaged portion and each comprises opposed shoulders, one adjacent pair of shoulders when engaged and the lever is suilciently tilted in one direction effecting retraction of the member from rack engagement, and the other adjacent pair of shoulders when the lever is suciently tilted in the opposite direction preventing accidental disengagement of the member from the rack.

5. In a clamp having an anvil, anopposed head and a member for moving the latter toward and away from the anvil for clamping and release purpose, the combination of a connection between the member and head comprising an intermediate member, complementary ball and socket means between the head and the intermediate member, a second intermediate member between first mentioned member and the iirst mentioned intermediate member, adjustable yielding means between the intermediate members which are tioned intermediate member together.

CLYDE L. GILBERT.

REFERENCES CITED The following referen'ces are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 438,850 Lockwood Oct. 21, 1890 Number 8 Name Date Walker May 2, 1893 Wrigley Jan. 9, 1906 Stewart Apr. 11, 1911 Krahulec Mar. 18, 1913 Parsons Nov. 15, 1927 Miller Jan. 19, 1943 Kellogg Apr. 6, 1943 Gordy et al July 6, 1943 Kirlin Aug. 3, 1943 Gearhart Feb. 13, 1945

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