US2675861A - Chair-adjusting mechanism - Google Patents

Description

April 20, 1954 c. E. CUSHMAN 2,675,861

CHAIR ADJUSTING MECHANISM Filed Nov. 17, 1950 2 SheetsrSheet 1 CLIFFORD E. CUSHMAN,

INVENTOR.

A TTORIVEV.

April 20, 1954 c. E. CUSHMAN CHAIR ADJUSTING MECHANISM 2 Sheets-Sheet 2 Filed Nov. 17' 1950 CLIFFORD E. CUSHMAN,

INVENTOR.

ATTORNE'K Patented Apr. 20, 1954 CHAIR ADJ'UsTING w Siamese-1m; m m

Appncetionmvmiier 17, 1956, SerisLNo 196,209

Tfiisinventionrelates to adjustabl'me ha mcai structur anduparticularly. to improved pos'ition adjusting; mechanisms er'riplo'yed therein. ,Tfi'e} 16 Claims: (01. Is s- 1 st) invention'possesses particular utiIityinjconnec V t gfln withsrecliningl chairs havi k and m'r his reason. it described in det inT ee non therew The 'sitio'n adjiisting mechanism of Ithisinventio'n is an improvement over one of these deseribed andclaimed in} copending patenti'applioa 1N6. 4,34'1jfi1ed lby meJanuaz-y T'2i6;194'8',' ent N6. 2j579,305'. In that application there is gi .dscribedie special 'form of position adjustingjnechamsm of the cantingc-lver typethat employs awsmooth rod andcanting leaves ,f-fie ngageable therewith as abrake elements for locginglthe. beck'of a. chair ina predetermined tilted =position'.. When locked these brake elementslhgol d the back of a chairset in a predtrminedfpositjion so long as the .compression and extension loads applied-Ito the position adjusting mechanism li'e belowcorresponding, .prede'te'rmined limits" lfi that'type of position adjusting. mech' v ism suitablecontrol means ereprovided foneleasing the -grip. ofl the canti'rig. iayewn to permit the chair occupant to :mo'veme acle from oneposition to another, In .-the chair back in a newflposi tionthe an ans .is manipulsted to C'ausmthecantiiig s'"togrip =the rod at th new position so ais ck c the position adjusting-H mechanism.

' prai'c itice in employ in'g that po'sitiizin adliils'iiiiig.-

mechanism, it has-been found that the cantin'g.

- leves often grip 1 the rod so gqu ickly that' a cettain. amount of impleasant. shock isvexpe ienced if the chair is -sti11 'in-motion atthe timeth'at theca'ntinglleaves 'engagethe rod c .7

Accordingly, it is one of: the objects .of the biiesent invention to provide an a-dj usteblech'ali r with an adj iista'ible posit'ioningedeviceof the fcanting} 6" lever type vthat cushions the shock of locking when thepositioningf deviceis ldckdwhil 1511c chflirbeckis-inmotionr I Another object of the invention ismpmvme siich an adjustable positioningsdvice whichhofds the chair' locked against-relatively. laLrge rear ward-tilting forcesJbnhwmc'h permits the back member to be moved iloLforward-tiltiiigl forces exceeding arelti vlylow Vahie.

Another object of the invention is.to provide a position" 'adjiistifighichamsnfof the (tintin l r Wpein'which the gi'iiroffth"e canting mem her upon the 'rod *membefiismppnd gradually diii in'glo'eldng. 7 e 1 v I nother obieot cr me invention is to provide tio an adjustable lpcsitmngmecnamsm Qftl'ie canting l'ver {type Whidh"'is"'0'f light weight and'of rugged inexpensive construction.

therodmember of a 'canting le'v'er'type positiofilockis designed'to be yieldagble or compressibie' firansversjeiyso, that the rod member is com:

presses s1ight13 when 'the 'c' anting lever bits .into itiza'uri io ckingpcc'tion. In the particular em:

b ocliinent, of the invention il lhstfeitefl herein .ithe y eiai'ng action ofthej rod memberis provilded'aby constfueting the ma member? in two parts,- namelyge; shaft member "and "a; sleeve member whichm e telescopicallg ai 'remged; vryfeffective cilshiofiing "effects" afe obtainedwith such "afiarngeme m by mpioymg a shaft member of tubui eo'n'struo't anew split or' divided "sleeve ya i'o'u's'imesn's by'which' the de- 20 with the attainment of other desired results mean il' ig device;

as cdntrdnable adjustbl' positioning mechanism for a 'tiltable chair i are set j'forth'in the {following detailed descfiption of one embodiment of the invention.

Inthe;"'(irtmrings wherein'theisame numbers in the severe-1 v e 's' refiiiesentlikeparts z Figfif'e' 1 "is "a; fragmentary "view of- .a, tiltabl'e chair incorporatingthe invention;

v v 2 1 :r agmentaryview' ShOWinQthe contfol n'fo'flocking and'iel'easin the position;

S i. "side elevations; view, partly, broken o the 'position 'ad'j iistiiig mechanisi'nf 1s ardetail'ed sectional view of 'the posidii'lstifig'fi echanism';

i sect'i(na;1View taken on" the plalne nustmted in Fig; 1 the Chair l0 acoinblish' the objects ofvgt h'e Dresentiriven- 7 fefratgmentary "views snowin iiigt-ameipasim rsm mechanism 2u'"com-' 3 28 in order to efiect the locking and the releasing of the position lock 22.

The position lock 22 comprises a canting lever in the form of a locking collar 30 that encircles a rod structure 3| that comprises a split sleeve member 32 and a shaft member 34 telescopically arranged. The shaft member 34 is of hollow tubular construction and is provided with a pair of slots 36 vextending lengthwise thereof and providing a transverse or radial elongated opening therethrough. The slots 36 are of equal length and terminate somewhat short of the ends of the shaft member 34 and are sometimes hereinafter referred to as a single slot. A tang 38 is firmly secured to the front or outer end of the shaft member 34 and extends outwardly therefrom. The tang 38 is suitably pivoted about a horizontal axis by means of a horizontally ex-' tending pin 40 secured to the stationary support. member IS. The rear or inner end of the shaft member 34 is capped by means of a disk 42.

The sleeve member 32 is in the form of two parallel rod members 44 of convex arcuate configuration separated by slots 45a and 45b. The two rod members are firmly secured to a tang 46 which is pivotallysupported on a horizontal pin 48 at the lower end of the frame 24 of the back member I2. A spring-loaded catch 50 is employed to hold the tan 4B in position on the pin 48. The front ends of the rod members 44 are secured together by means of a pin 52 that extends through the shaft slot 36.

The sleeve member 32 and the shaftmember 34 are of circular cross-section and are frictionally engageable and they are machined and treated to provide a pair of nongalling long-wearing contacting surfaces. With this arrangement the rod structure 3! is compressed when the back member I2 of the chair is tilted rearwardly and is extended when the back member l2 of the chair is raised to its upright position. Dur-,

ing compression and extension of the rod member 22 the sleeve member 32 and the shaft member 34 move longitudinally in sliding frictional engagement. j

Therange of movement of the sleeve member 32 and the'shaft member 34 is determined by the length and position 'of thes1ot'36. The pin 52 engages the front end of the slot 36 in the most compressed positioncorrespondin to the most rearward tilted position of the "back member l2. The pin 52 engages the rearward end of the slot 36 in the upright or most forward position of the back member l2.

'The locking collar 30 is pivotally supported at the outer end of a pivot arm 54 that is secured to the shaft member 34 at a position aligned with one of the slots 45a of the split sleeve member 32; The pivot arm 54 is itself pivotally attached to the shaft member 34 by means of a finger 56 that projects loosely through a short slot 58 in the shaft member34, thus permitting the outer ends of the locking collar 30 to move laterally relatively to the axis of the sleeve member 32." The pivptarm '154 is sufli'ciently. narrow tov permit the sleeve member 32 to move past it freely during .extensionand compression. A notch 59 just above the finger 56 and a straight edge 60 at the rear end of the finger 56g$erve to retain the pivot arm 54 in the slot 58 without, however, interfering -.with slight pivotal. movement of. the pivotarm 54. The pivoting of the locking collar 30 on the pivot arm 54 is. accomplished by means of a pin 62 that projects through the outer end of the pivot arm 54 and through the opposite sides of a U-shaped bracket 64 projectin outwardly from the lockin collar 36.

The locking collar 30 is arranged to be canted forwardly about the pivot pin 32 so that walls 66 on opposite sides of the aperture 68 of the locking collar are engageable with the outer surface of the sleeve member. 321at thezec'lges of the slots 45a and 451). In practice, the aperture 68 is of oval or elliptical configuration having a minor axis X just slightly greater than the outer diameter of the sleeve member 32 and a major axis Y of somewhat greater length. With this arrangement the outer edges of the rod members 44 intermediate the slots 45a and 45b engage the sidewalls 61 of the aperture 68 and the slots 45a and 45b are slightly narrowed as the locking collar 30 bites into the sleeve member 32.

A locking lever 76 is pivoted on the other side of the rod member 22 from thepivot arm 5%. The pivotal connection of thelocking lever' 10 is accomplished by means of a pivot pin 12 projectin therethrough and also through the opposite arms of a second U-shaped bracket 74 extending from the locking collar 30 on the opposite side thereof from the first -U -shaped bracket 64. H

A straight arm' 76 at the inner end of the locking lever 19 projects through a'window 18 in the locking collar and through the adjacent sleeve slot 45b and into a short slot 8!l formed in the shaft member 34. A tension spring 8 2 is attached at one end to the outer end of the locking lever 13 and at the other end to the shaft member at a position aligned with the sleeve slot 451). The tension spring 82'normally drges the outer end of the locking lever 10 forviiardly and counterclockwise of the pivot pin '12. During this action the inner arm 76 of the locking lever 16 engages the rear end 84 of the slot 80, thus permittin the locking lever to pivot about this point thereby urging the locking collar 30 counterclockwise and forcin the walls 66 into gripping engagement with the sleeve member 32. A shaft 86'extends transversely through the shaft-member 34 ina plane common with the major axis Y'of the collar member 30. "The shaft 86is journalled to the Shaft member 34 and is rotatable therein. A crank 33 atone end of the shaft is connected by means of a cable 92 to the endof the control lever 26 that is concealed within the chair arm 28. A crank 34 at the other end of the shaft 36 is connected with the outer end of the locking lever 76 by means of a link 96-including a turnbuckle 98. With the arrange ment illustrated downward movement of the ex posed end of the control arm 26 causes the shaft 86 to rotate and to operate through the linkage comprising the crank 94 and the link 96 to push the outer end of the locking lever 16 clockwise and in opposition tothe force of'thespring 82; When this occurs the inner arm 16 first engages the forward end of the slot 33 causing" the locking lever to pivot at this point and'to'move the locking collar 30 clockwise. As the locking collar 30is moved clockwise about'the pivot pin 62 the grip of the aperture walls 66. on the sleeve member 32 is released. V i v j In order for the seat occupant to move the back member l2 of thechair, the control lever 26 is pressed downwardly causing the grip of the locking" collar 30 of the sleeve member 32fto'be re leased. With the grip of the locking-collar 30 released i'ms an easymatterto'tilt theback mm: A

ber l 2 forwardly on rearwardly :to any desired positions During this :actioni'the shaft member the -locki nggleverlll counterclockwise andto cause the-locking collar 30'- to grip the sleeve member 32. Ifrthe-back'member: :l 2 is in :motion at this time, 4 th'eshock of-locking is-cushionedtoa large extent by virtue o'f thevfact that the lockin'g collar compresses thesleeve member 32- and the' shaft memher- 3H 1 1 As compression-, spring: 1034s arranged within the sleevemember between-the lane 46 andthe disk 42. This icompression spring acts to-exte'nd: the -rod"member= 2 2- 'when the-gripof the locking collaris meleased}: thus aiding the: occupant of the lchair to: tilt the back member I 2 forwardly. Though? the spring a l also'resiststhe backwardtilting of the back. member, the-strength 'ofthe springis not-so great as to seriously interfere with is such action. As the back member l2 is -forced rearwardly while'the lockingdevice- 22 is in locked condition; a. compression force is applied to the opposite ends a of the rod member 2 2 tendingto forcerthe: shaft membera34' into the sleeve member 32:. As thisoccurs the-locking collar 36 bites'furthen-into the. outerzsurface of the sleeve member 32' compressing} it against the shaft member -34 andcompressing boththtasleeve member 32' and the shaft member 34 as the backward force'applied to the back member 12 is'increa'sed- Thus, the greater the backward itilting force applied to the-"backxmember J 2 the stronger is the forceapplied by the locking collar to therod member 22. z "Finallyyhowever, when the rearward tiltingforce applied to the "back member 12 exceeds a predetermined relatively highx-valu'e, the shaf-t member 34 commences to slip .with in the sleeve member 32 and: the slipping .is resisted @by the frictional force between the sleeve member 32 and the locking collar 30 and'also by the-frictional force between thesleeve member 32andthe-shaft member, 34; Inpractice,: itqis found that -the value of the. load limit against: whichrthe locking device; 22 is :capable of. holdingsbefore slippingds determined inpart by the transverse stiffness ofthe shaft member 34 and-the sleeve member 32; Thus, for example, the limit of loadzwhi'ch-can be held-bytheglocking device 22 in-compression may be increase'd byxincreasing the thickness =ofthe wall of the; tubular shaft member 34.

As-theback member. I2 is" forced forwardly" while-the: locking: device 22 is in lockedcondition; a tensionforce is applied :tothe opposite ends of the-rod member 22 tending; to" draw. the shaft; member 34 out otthe-sleevemember 321 As this occurs; the bite -of thewlockingcollar 30 on the outer surface of the sleeve member :32 and theforce between the sleeve member 32 and the shafti member 34: is? slightly relieved: more and moreas therforward .tilting :force applied :to the back member I 2 is increased; During this action, how ever; the tension spring 82 keeps the locking col lar. urgedagainstthe sleeve member 32 in looking engagement therewith; Finally, however,- when the forward tilting force applied to the back-- member l2 exceeds a predetermined relatively low .value, the shaft member 34 commencesio slip within the sleeve member 32 and-the slipping islfresisted by thefrictional force between the sleeve member 32 and the 1 locking collar 30 and changes which will also by tne rrictienar iorcemetween thesieeve member *3 2' and the-"shaft member 3t;

Tfi' sti" netherirtension fdrces againstwhi 1 1 I1 is; capable of holding- S determined in with "the streng't-herme tension spring 82 and in -p'ar by thedevefa'ge of the lock lever J0" amioftliei glockilig' ringd05 By setting the threshold at which s1ippi ng' *-mayoecurat a conveniently 10w va'l-meflt becomes possiblefora person to tilt tlie' back member l 2 "upwardlyby means er ardrwardly exerted force applied to the upper end ofl 'the ba'elt memberevefnthon'ghthe" 3 control lever-16 i's iri lo'eked position arid-even though the chair-m'occupied From tli'e reregemg descriptionof the iriveri tion -it -is readily seen tliat 'a--' posi-tion--adj ii'sti'ng mechanism mas -been providedwhich-is capableof- 'cushionin shoek during the *lockingaction main'ing cked' against a widerange of for'ces exerted m one"- direction thereon below r a 'rela--- tively larg'e load limit but is -'capable on-being readily adjusted by relatively small forces exerted in the opposite direction --above a relatively-srr'fall- 1oad -liiniti a Whilethe invention has been described with particularreference to-its applieati'on'to-a reel mg chair-, it will be. under-stood what it also be applied toother istriicthres" arrangements inwhich it is desired to lock 5 two main members in predetermined relative positions; while m y invention has been described witli= reference tothe employment of" a sleeve-utilizing a pairpf slots that separate two rowmembers, more-slots may be -employed-= if desired but? in any eve'nt some 'of the' adv a nltfig'cs of 1 my invention may be obtained by employing a sleeve provided with only a single slot! gum; while- =m y-invention has been described with l referenceto a "-rod strifeture'em'ploying-a shaftfnember that-telescopically engages a split 'sleevemember; it will be clear that other rod structures-may be employed' and some of l the advantagesof v the invention still be obtained. Thus; altliough" only one particulan embodiment of the invention has been spec'iflcall-y v disclosed herein, -it apparent; that 'the inven-" tion-is not limitedth retobut is capable ofa wide variety of mechanical embodiments: i Imadditior'f the modifications mentioned 51 above, var-ions flw -readi1y suggest them-* selvesto those skilled in the artmay bemade in the material, I? form, detailsof construction" and: arrangement of the'elementswithout de'palrt' ing nom the" sp 1 of-jthe lnventionp Inasmuch as ne f regoin 1 and -many: other changes'may be'im'ade" while still emplo -mg Nari ous" features ofthe invention," it isto be under stood that the specifi 'tion 'herein is-illustrative only and that ref is to-be had to the appended claims for' a definition-of the-limitsof the invention?- The invention claim'ed'is: i

1.- In-"an-adjustabl'e chair comprising aspair of relatively movable: seat" members; namely; -a sup-r port meziiber and a tiltab'le. back'm'ember; the im-v provement which comprises an adjustable posi--. tion lock for-moldingsaid back member set in a predetermined tilt position;'said adjustable posi z tien: lock comprising a pair" of -mutually spacedparallelrod": members connected' as a 5 unit *with one? of =said" seat members; said" unit 'having' "a transverse: compressibility large compared 1 with its longitudinal--- compressibility, and canting means connected with the other of-- said -seat members, said' canting means having; opposite ae'z aei.

walls frictionally engageable with the surfaces of the respective rod members, said rod members being movable lengthwise relative to said canting means, resilient means applying a force to said canting means to urge said walls against said surfaces whereby longitudinal movement of said rod members relative to said canting means is resisted, and means for reducing the force of said resilient means to release the grip of said canting means on said rod members.

2. In an adjustable chair comprising a pair of relatively movable seat members, namely, a support member and a tiltable back member, the improvement which comprises: an adjustable position lock for holding said back member set in a predetermined tilt position, said adjustable position lock comprising a split rod member connected with one of said seat members, said split rod member having a transverse compressibility large compared with its longitudinal compressibility, and a canting member connected with the other of said seat members, said canting member having an aperture therein, said split rod member being movable lengthwise through said aperture, the walls of said aperture being frictionally engageable with opposite surfaces of said rod member, resilient means applying a force to said canting member to urge said aperturewalls inwardly against said surfaces of said rod member whereby longitudinal movement of saidrod' 1 member through said aperture is resisted, and means for reducing the force of said resilient means to release the grip of said canting member on said rod member. v

3.. In an adjustable chair comprising a pair of relatively movable seat members, namely, a support member and a tiltable back member, the-improvement which comprises: an adjustable position lock for holding said back member set in a predetermined tilt position, said adjustable position lock comprising a rod structure connected with one of said seat members and canting means connected with the other of said seat members, said rod structure having a transverse compressibility large compared with its longitudinal compressibility, said canting means having an aperture therein, at least part of said rod structure being movable lengthwise through said aperture, the walls of said'aperture beingfrictionally engageable with surfaces on the opposite sides of said part of said rod structureresilient means applying a force to said canting means to urgesaid walls inwardly against said surfaces of said rod structure whereby longitudinal movement of said rod structure through said aperture is-resisted, and means for reducing the force of said resilient means to release the grip of said canting means on said rod member. l

Y 4. In an adjustable chair comprising apair of relatively movable seat members, namely, a support member and tiltable back member, the improvement which comprises: an adjustable position lock for holding said back member set in a predetermined tilt position, said adjustable position lock. comprising a shaft member connected with one of said seatmembers and a split sleeve member connected with the other of said seat members, said sleeve-member telescopically engaging said shaft member, canting means pivot ally supported on said shaft member, said canting means having an aperture therein, said sleeve member being movable lengthwise through said aperture, 'the walls" of said aperture being fric tionally engageable with opposite external surfaces of said sleeve member, resilient means for 8. urging said aperture walls inwardly against said surfaces of said sleeve member whereby longitudinal movement of said sleeve member through said aperture is resisted, and means for reducing the force of said resilient means to release the grip of said canting means on said sleeve member.

5. The combination described in claim 4 wherein said shaft member is a hollow tubular member.

6. An adjustable position lock for holding a pair of members set in predetermined relative positions comprising: a pair of mutually spaced parallel rod elements adapted for connection as a unit with one of said members, said unit having a transverse compressibility large compared with its longitudinal compressibility, and canting means adapted for connection with the other of said members, said canting means having opposite walls frictionally engageable with the surfaces of the respective rod elements, said rod elements being movable lengthwise relative to said canting means, and means for urging said walls against said surfaces whereby longitudinal movement of said rod elements relative to said canting means is resisted.

7. An adjustable position lock for holding a pair of members set in predetermined relative positions comprising: a rod structure adapted for connection with one of said members and canting means adapted for connection .With the other of said members, said rod structure having a transverse compressibility large compared with its longitudinal compressibility, said canting means having an aperture therein, a part of said rod structure being movable lengthwise through said aperture, the walls of said aperture being frictionally engageable with surfaces on the opposite sides of said part of said rod structure, and means for urging said walls inwardly against said surfaces of said rod structure whereby longitudinal movement of said rod structure through said aperture is resisted.

- 8. An adjustable position lock for holding a pair of main members set in a predetermined relative position comprising: a shaft member adapted for connection with one of said main members, a split sleeve member adapted for connection with the other of said main members, said sleeve member telescopically engaging said shaft member, canting means pivotally connected to said shaft member, said canting means having an aperture therein, said sleeve member being movable lengthwise through said aperture while the walls of said aperture are frictionally engaged with opposite external surfaces of said sleeve member, and means for urging said aperture walls inwardly against said surfaces'of said sleeve member whereby longitudinal movement of said sleeve member through said aperture is resisted.

9. A position lock as defined in claim 8 wherein said shaft member has a transverse compressibility large compared with its longitudinal compressibility.

10. In an adjustable position lock for holding a pair, of main members set in predetermined relative positions, a shaft member adapted at one end for connection with one of said main members, a sleeve member telescopically engaging said shaft member and adapted at one end for connection with the other of said main members, said sleeve member having a slot extending lengthwise thereof, a pivot arm extending outwardly from said shaft member at a position aligned with said slot, and canting means pivotally supported at the outer end of said pivot arm, said flengthwise between said walls.

" I 11. In an adjustableposition,lock:foriholding 'a pair'of main members set in a predetermined :relative position, a tubular member adapted at Jone send for connection with one of said main (0 members, a sleeve member telescopically engaging said tubular member externally thereof and adaptedat one en'd'for connection with the other of said main members, said sleeve member having a slot extending lengthwise thereof, a pivot. arm

extending outwardly from saidstubular'member ata position aligned with said slot, and canting means pivotally supported attheouter end of said pivot arm, said canting 'means having a pairof walls disposed respectivelyon opposite sides of i said tubular member'and said sleeve member, said walls being adapted to-engage the outer surfaceof said sleeve member, said sleeve member being-movable lengthwisebetween said walls.

12. In an adjustable position lock for holding a pair of main members set in a predetermined relative position, a shaft member adapted at one end for connection with one of said main members, a sleeve member telescopically engaging said shaft member and adapted at one end for connection with the other of said main members, said sleeve member comprising a pair of sleeve elements separated by slots extending lengthwise thereof on opposite sides thereof, a pivot arm extending outwardly from said shaft member at a position aligned with one of said slots, canting means pivotally supported at the outer end of said pivot arm, said canting means having an aperture therein encircling said shaft member and said sleeve member, said sleeve member being movable lengthwise through said aperture, and a locking lever pivotally connected to said canting means on the opposite side of said sleeve member from said pivot arm, the inner end of said locking lever being pivotally connected with said shaft member at a position aligned with said other slot. I 13. In an adjustable position lock for holding a pair of main members set in a predetermined relative position, a shaft member adapted at one end for connection with one of said main members, a sleeve member telescopically engaging said shaft member and adapted at one end for connection withthe other of said main members, said sleeve member having a slot extending lengthwise thereof on opposite sides thereof, a pivot arm extending outwardly from said shaft member at a position aligned with said slot, canting means pivotally supported at the outer end of said pivot arm, said canting means having an aperture therein encircling said shaft member and said sleeve member, said sleeve member being movable lengthwise through said aperture, means including a spring applying a force to said canting means for urging the Walls of said aperture against the outer surface of said sleeve member whereby longitudinal movement of said sleeve relative to said canting means is resisted, and means for reducing the force applied by said spring to release the grip of said canting means on said I sleeve member. p

14. An adjustable positionlock for holding a pair of main members set in predetermined relative positions comprising: a shaft member adapt-c ed at one end for connection with one of said main members, a sleeve member telescopically engag :ing said shaft'member and adapted: 'at oneaend for connection with the other of'said main. mem- V-bers; said sleeve-member'comprising apair'of sleeve elements separated by slots extending lengthwise thereof on opposite sides thereof, a

pivot arm extending outwardlyf-rom' said. shaft member at a position aligned with one of said slots, canting means pivotally supported" at the outer enduof said pivot arm,.said canting means having an aperture therein encircling said shaft member and said-sleeve member, said sleevermem- .ber beingmovable lengthwise through said aper- -forzurging'the walls of said aperture inwardly against the surfaces of said sleeve member whereby longitudinal movement of said sleeve member throughsaid aperture is resisted, a rotatable shaft extending through said shaft. member, anda linkage interconnecting. said locking lever with said rotatable shaft for: moving saidlocking-lever in opposition to the force exerted thereon by said resilient means to release the grip of said canting means on said sleeve member.

15. An adjustable position lock for holding a pair of main members set in predetermined relative positions comprising: a shaft member adapted at one end for connection with one of said main members, said shaft member bein divided lengthwise throughout a substantial portion of its length by a shaft slot extending transversely therethrough, a sleeve member telescopically engaging said shaft member and adapted at one end for connection with the other of said main members, said sleeve member comprising a pair of sleeve elements separated by a pair of sleeve slots extending lengthwise thereof on opposite sides thereof, a cross member extending through said shaft slot and securing the free ends of said sleeve elements together, the

ends of said shaft slot acting as stops to limit the range of relative longitudinal movement of said shaft member and said sleeve member, a compression spring enclosed by said sleeve member for urging said shaft member and said sleeve member apart into an extended position, a pivot arm extending outwardly from said shaft member at a position aligned with one of said sleeve slots, canting means pivotally supported at the outer end of said pivot arm, said canting means having an aperture therein encircling said shaft member and said sleeve member, said sleeve member being movable lengthwise through said aperture, and a locking lever pivotally connected to said canting means on the opposite side of said sleeve member from said pivot arm, the inner end of said locking lever being pivotally connected 'with said shaft member at a position aligned with the other sleeve slot.

16. An adjustable position lock for holding a pair of main members set in a predetermined relative position comprising: a shaft member adapted at one end for connection with one of said main members, said shaft member being divided lengthwise throughout a substantial portion of its length bya shaft slot extending transversely therethrough, a sleeve member telescopically engaging said shaft member and adapted at one endfor connection with the other of said main members, said sleeve member comprising a pair of sleeve elements separated by' l l sleeve slots extending lengthwise thereof on opposite sides thereof, a pivot arm extending outwardly from said shaft member at a position aligned with one of said sleeve slots, a cross member extending through said shaft slot and securing the free ends of said sleeve elements together, the ends of said shaft slot acting as stops to limit the range of relative longitudinal movement of said shaft member and said sleeve member, a compression spring enclosed by said sleeve member for urging said shaft member and said sleeve member apart into an extended position, canting means pivotally supported at the outer end of said pivot arm, said canting means having an aperture therein encircling said shaft member and said sleeve member, said sleeve member being movable lengthwise through said aperture, a locking lever pivotally connected to said canting means on the opposite side of said sleeve member from said pivot arm, the inner end 01 said locking lever being pivotally connected with said shaft member at a position aligned with the other sleeve slot, a tension spring connected between the outer end of said locking lever and the walls of said aperture inwardly against the locking lever with said crank for moving said the outer end of said shaft member forurging 25 looking lever in opposition to the force exerted thereon by said spring to release the grip of said canting means on said sleeve member.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,948,991 Molly Feb. 27, 1934 2,319,743 Morey May 18, 1943 2,329,932 Nelson Sept. 21, 1943 2,469,716 Di Santi May 10, 1949 2,580,924 Turner Nov. 21, 1950 FOREIGN PATENTS Number Country Date 15,645 Great Britain July 31, 1905

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