US2518334A - Locking device - Google Patents

Description

' Aug. 8,1950 w. F. KLEMM 2,518,334

LOCKING DEVICE Filed sept. s, 1945 2 sheets-sheet 1 INVENToR. M/zZZ'd/n Fila/707e.

Aug. s, 195o w. F. KLEMM 2,518,334

` LOCKING DEVICE Filed sept. s, 1946 n 2 sheets-sheet 2 BY /40/ .E

Patented ug. 8, 12950 UNITED vS".l`ATl-SVV PATENT.V OFF'C LOCKING DEVICE j Wimamr. .Klemm, Detroit, Mien. Y Application September 3, 1946; Serifal'No; 694,651

(icl. 19a- 8) 8 Cla-ims.

This invention relates to clamping fixtures, and more `particularly toxclamping iixturesl adapte yed to clamp an` .object with a predetermined clamping force and to lock therfmture .against release.v i

The'main objects of the present invention are: toprovidean improved clamping iixtnre adapted to` clamp an object with a predetermined ,clamp- "ing force 'and'. then lock in Lposition to prevent damage touor release of theA` objectclarnped; to provide an improved vclarrniing xture of rthe above generally indicated type which is simple in construction, economical of `manufacture and assembly, andi reliable and eihoient in operation; towp'rovide aclamping iixture' withimproved :means for readily adjusting the fixture to lock in position upon the application of any desired predetermined yclamping force` upon anlo'bjectto be clamped; and to generally improve the construction and operation of clamping xtures of the above generally indicated'type.

Otherobje'ctsand features of: novelty .of the invention will be .specifically pointed: out-or will ibecomeapparent Vwhen referring, tor a better understanding foi the invention', to the following Idescription taken in conjunction -wf'ith theaccompanying. drawings, wherein:

.Figure l is a plan. viewshowing. partsA in `section,l of a clampingfixturexembodying features of this invent-ion;

IFig. 2. is" afsectional view `of. the: structurey illus trated inflig.4 1,. taken .substantially along' the linev 2*-2 thereof;

Fig. 2?` isv asectilonal View or a clamping fixture, similar tothat illustrated inA Fig. l, showing a further form which the invention may assume; .w Fig. 4L is. a sectional view' .ot structure, similar to that illustrated in;- Fig.1 la/showing a further form-1 whichrtheinvention mayassume;l

5t-is asecti'onal View of another form. or .clamping fixture i, which embodies features: or? :the

' Vpresent'nvention;

fis" integrally formed thereon for slidably supporting twoV vertically disposed parallel columns t8 anda horizontally disposed shaft 2l). Each of the columns i3 has a vertically' disposed rack 22 formed along one side thereof, and the shaft 2|] has an elongated spur gear 24` integrally formed thereon which continuouslymeshes with the racks 22 for moving thecolumns I`8 verti lcally in the housing Iii when rotated. At Vtheir upper ends; yeach of the columns I8 is' provided with an upwardly projecting stud` 26 -which extends through the plate 28 and receives a nut 3B. The pla-tcl8 seryesas- ,a second clamping jaw and cooperates with the dat portion :I4 of the base I2 to clamp an object therebetween.

One end of theshaft 2li has a head 232 integrally formed thereon adapted to engage the housing I6. inV which the shaft is rotatably supported. Adjacent tofits' other end, the shaft has a threaded portion 34 which extends outwardly of said housing.r A handle .36 is threaded on saidportion 34 and has a cylindrical bore 381' formed in its :outer end. One end oi a compression coil spring .40 is received in said bore for engagement with .said handle and the other end is received in a recess -of a nut 42 threaded on the outer end of the shaft 20. The' nut d2 may be adiusted on the shaft 2i), to produce any `desired compression in the spring 40 and may be securely held in that ,position by kan Alllen headset screw 44 or like means. A

In the construction above described, when an objectto be clamped is placed between the jaws 'I4 and 28- and the handle 36 isl rotated ina' ycounterclockwise direction as viewed from the right in Fig. 1, the shaft 2B is' caused to turn with the vhandle as a resultV of the'frictional engagement between the threads on the handle 36 and the threads on the shaft 20; The amount of this frictional force may be varied by adjusting the nut 42 to alter the compression of the spring 40, as above described. This rotation of the handle 36 and the shaft 20 drives the column I8 vertically downward, as viewed in Fig. 2, through the engagement of the spurgear ,24:and the racks 22. The jaw 28 is moved toward the jaw I4- in this manner until a predetermined amount of gripping force is .applied to the4 object held therebetween, at which time the handle 3S begins to turn relative to the shaft 20 to be advanced on the threaded portion 34 .of the shaft toward the head 32 until the head 32 and the handle 36 grip-opposite sides of the ,housing lr6 and thereby prevent further rotation of the handle. This produces a wedging action between the threads on the handle 36 and those on the shaft 20, and a pressure between handle 36 and the housing I6 which combine to lock the handle 36 in position against inadvertent movement in a clockwise or releasing direction. Further movement of the handle 36 in a clamping or counterclockwise direction is positively prevented by this locking engagement.

When desired the clamp may be easily released by rotating the handle in a clockwise direction. This causes the handle 3E to advance along the shaft 20 until the housing I6 is no longer gripped between the head 32 and the handle 38, after which the shaft 20 turns with the handle 30 as a result of the frictional force developed between the handle 35 and the shaft by the spring lllV a described above. l

It will be apparent that if right-hand threads `instead of the left-hand threads illustrated are employed on the shaft 20, the clamping action will be effected by rotating the handle in the opposite direction. The direction of movement of. the clamping jaws for a given movement of the handle may also be reversed by disposing the shaft and associated gear on the opposite side of the .columns from that shown.

In the modified form of the invention illustrated in Fig. 3, the shaft 50, corresponding to the shaft 20, extends between'the vertically disposed columns 52, corresponding to the columns I8, and the gear 54 carried by the shaft 50 engages a rack formed on one of the columns 52. The handle S, corresponding to the handle 36,

'has a blind bore 58, the outer portion of which is threaded. This form of the invention is particularly adapted for clamping fixtures in which a relatively light clamping force is desired, and accordingly a small and relatively weak compression coil spring 60 is disposed within the inner portion of the bore'58. One end-of the spring 60 engages the handle at the inner end of the bore 58 and the other end of the spring 6G engages the outer end of the shaft 50 upon which the h andle 58 is threaded. 'The spring 60 functions to produce a-frictional engagement between the handle 58 and the shaft y5E) corresponding to but-much smaller'than the frictional engagement between the handle 36 and the shaft 2D in the embodiment described above.

In the `modification illustrated in Fig 4, the handle 62 differs from that of the construction shown in Fig. 3, in that the blindbore formed therein has an internal portion S which is threaded for engagement with the threaded end of the shaft |36 and an outer portion 68 which is enlarged to receive a coil spring l0. Y The spring surrounds the shaft 65 and one end thereof engages the gear 'I2 and the other end engages the handle 52 at the inner end of the outer enlarged portion '68 of the bore. This larger spring 10 permits a greater clamping force than the spring 60 while bothY features are designed for a set load that can only be changed by changing the springs. Another formof the invention is illustrated in Fig. 5, that wherein a fixture employs a shaft 80 having a tapered head 82 corresponding to the head 32 and a gear S4 engaging a rack 8E formed on a single column 88. The portion of the shaft 8G extending outwardly of the handle Si?, which is threaded thereon, has an axially extending groove formed therein which receives a complementary tongue. formed on an inner spring sup- Cil port member S6. The member 86 is slidable axially of the shaft and has a conically shaped surface 98 on the inner side thereof adapted to engage a complementary conical seat |00 formed on the handle 9G. A nut |e2, similar to the nut 42, is threaded on the outer end of the shaft 80 and a compression coil spring |04 is supported between the inner spring supporting member 95 and the nut |02.

. It will be appreciated thatthe clamping fixture of Fig. '5. permits a substantially greater clamp- Ving force to be applied'to the object being clamped than is possible with the clamping fixtures -so far described. This results from the additional frictional force which is set up between the conical surface 98 of the inner spring member 96 and theA conical seat |00 formed in the handle which must be overcome in addition to the frictional force of the threaded engagement between the handle 90 and the shaft 8e before the handle may turn relative to the shaft and advance along the shaft to grip the 'housing |05 between the head 82 on the shaft and the handle 90.

These frictional forces effective to cause the handle 90 and the shaft 80 to turn as a unit may be variedin this construction as in the embodiment illustrated in Figs. 1 and`2, by adjusting the outer spring support |02 along the shaft 80 to vary the pressure of the spring |04.

The form of the invention illustrated in Fig. 6 differs from the construction 4shown in Figs. l and 2 in that a torsional spring ||0` is employed, havingits inner end anchored in the handle I|2 and its outer end anchored'in a nut I4 threaded -on Ythe outer'end of the shaft H6.' The spring ||0 is arranged to apply a torque to the nut H4, .tending to thread the nut outwardly on the shaft H6 and the nut I I4 'is held against movement in that direction by a second nut ||8 threaded on the outer end of .the shaft I6.

In this construction,A when the handle ||2 is rotated in a clamping direction or in a' counterclockwise direction,V as viewed from` the right in Fig. 6, the torque action of the spring IIB, resisting further winding up of the spring, causes the shaft ||6 to turn with the handle until the clamping force applied is such that the force required 'tov turn the handle I I2 is greater than the torque action of the spring ||0,.at which time a handle ||2 turns relative tothe shaft III. YThe spring I'IIJ thereafter is further wound up until the handle I I2 and the opposite end of the shaft grip the housing ||9 and preventgfurther movement of the handle as in the above described structures.

Fig. 7 illustrates analternative means which may be mounted on the end of the shaft opposite to that which receives the handle and which replaces the heads 32 and 82 integrally formed on the shafts in the constructions Yillustrated in Figs. l and 5, respectively. This alternative means comprises a nut |20 threaded on an outwardly extending Yportion of the shaft |22 and secured against rotation relative thereto by a cotter pin |24. The nut |20 grips the housing |26 i 'the samemanner as does the head 32 and may be removed to permit the shaft |22 to be inserted from either side of the housing |26.

Fig. 8 illustrates a modified formof thread construction whichmay be employed in any of the above described clamping fixture constructions'to materially increase the clamping force which may be appliedthereby. In this construction the threadsfare formed with .a substantially :atraen increased 'thread angie.. said :angie being that between adiaoentfthreadffaces '13u andl'sz. The deptnof theithreadis reduced by providing hats $134 at the bottom of vthe threadsrand similar flats .136 `at thewapex.' This construction provides `a 'substantially'increasedf wedgingxaction between "the fthreaded velements' .and therefore a substantiallysgreater -frictional force therebe- =betweenyvliich:inustbe overcome before one element may turn relative totherother.

(As illustrated `in .9, the invention is readily applicable to clamping xtures having a C-shaped base |40, the-upper arm 'M2 of which carries one clamping jaw i443 In thisconstruction the plate 6, mounted on the column |748 corresponding-to the column I8, serves as the lower clamping jaw and the movementY ofthe Icolumnv l''in a clampingdirection is upwardly,.asf opposed to the conco-pending application, Serial No. 573,432, filed January 18, 1945. Assurance is had that the specimens examined are clamped with a like pressure and that no damage results thereto from the clamping operation.

What is claimed is:

l. In a clamping xture, a pair of relatively movable elements employed for clamping an object therebetween, a rack mounted on one of said elements, gear means adapted to engage said rack vmounted on the other of said elements, a shaft operatively connected to said gear means and having a threaded portion on one end thereof, a handle having a threaded engagement with said threaded portion, means biasing said handle axially of said shaft, and gripping means operable upon the application of a predetermined clamping force upon said object by said elements to grip one of said elements and lock said handle against further movement in a clamping direction.

2. In a clamping xture, a pair of relatively movable elements employed for clamping an object therebetween, a rack mounted on one of said elements, gear means adapted to engage said rack mounted on the other of said elements, a shaft operatively connected to said gear means and having a threaded portion on one end thereof, a handle having a threaded engagement with said threaded portion, adjustable means for variably biasing said handle axially of said shaft, and gripping means operable upon the application of a predetermined clamping force on said object by said elements to grip one of said elements and lock said handle against further movement in a clamping direction.

3. In a clamping fixture, a pair of relatively movable elements employed for clamping an object therebetween, a rack mounted on one of said elements, gear means adapted to engage said rack mounted on the other of said elements, a shaft operatively connected to said gear means and ha ing a threaded portion on one end thereof, a ha le having a threaded engagement with said 4threaded portion, means including a coil spring biasing said handle axially of said shaft, and gripping means operable upon the application of a predetermined clamping force upon said objects by said elements to grip one of said elements and lock said handle against inadvertent movement.

f1, In a clamping xture, a pair of relatively .movable elements employedfor clamping arrobject therebetween, a rackk mounted ont` one ofsaid elements,` gearr means adapted to engage said rack mounted onthe other of said elements, ya shaft .operatively connected to said gearr means and having a threaded portion on one endthereof,1a handlev having a threaded engagement with "saidthreaded portion, a spring support mounted on'said one end of said shaft, a compression vspring vengaging :said .spring support .and said handle to bias said handle axially of said shaft, and grippingmeans operable upon'the application of apredetermined clamping force upon said object by said elements to` grip one of said elements and locksaid handle against inadvertent movement. v f

5.V In Va clamping fixture, a pair of relatively movable elementsemployed yfor clamping anob- Aject therebetween,v a rack mounted on one of said elements, Vgear `means adapted to engage said rackl mounted on .the other of said elements, a

vshaftoperatively connected to said ,gearg means Aand having a threadedportion on one end'thereof, a handle having a threaded engagement with said threaded portion, a spring support mounted on said one end of said shaft, a compression spring engaging said spring support and said handle to bias said handle axially of said shaft, and gripping means operable upon the application of a predetermined clamping force upon said object by said elements to grip one of said elements and lock said handle against inadvertent movement, said gripping means including a head formed on the other end of said shaft from said thread and an integral portion on said handle having a surface adapted to abut the opposite side of said one of said elements from the head to clamp said last element therebetween.

6. In a clamping fixture, a pair of relatively movable elements employed for clamping an object therebetween, a rack mounted on one of said elements, gear means adapted to engage said rack mounted on the other of said elements, a shaft operatively connected to the gear means and having a threaded portion on one end thereof, a handle received on said threaded portion and having a threaded engagement therewith, a spring support threaded on said one end, said spring support being adjustable along said threaded portion and having a setscrew for securing said spring support in an adjusted position, a coil spring engaging said spring support and said handle to bias said handle axially of said shaft, and gripping means operable upon the application of a predetermined clamping force upon said object by said elements to grip one of said elements and lock said handle against inadvertent movement.

7. In a clamping xture, a pair of relatively movable elements employed for clamping an object therebetween, a rack mounted on one of said elements, gear means adapted to engage said rack mounted on the other of said elements, a shaft operatively connected to said gear means and having a tapered head on one end thereof and a threaded portion on the other end thereof, a handle having a threaded engagement with said threaded portion, means operatively connecting said handle to said shaft to cause said handle and said shaft to turn as a unit until said object is clamped between said elements with a predetermined clamping force, gripping means operable when said object is clamped with said predetermined clamping force to grip one of said elements and lock said handle against inaclyer` fcal member.

8. In a clamping xture, a pair of relatively movable elements employed for clamping an ob- `'ject therebetween, a rack mounted on one of said elements, a gear means adapted to engage said rack mounted on the other of said elements, a

`shaft operatively connected to Said gear means and having a threaded portion on one end there of, a handle mounted on said one end of said shaft and having a, threaded engagement therewith, a spring support mounted on said one end fof said shaft, means preventing rotation of said spring support relative to said shaft in at least Number one direetiomagtorsional spring having one end anchored inf said spring support and the other Vend anchored in said vhandle and being eiective to' cause saidjhandle and said shaft to turn as a -unit until said object isv clamped between said elementslwith a predetermined clamping force,

land gripping meansyoperableupon the application of said predetermined clamping force to grip one .of said velements-and lock said handle against inadvertent movement,

, REFERENCES CITED Y The following references are' of record in the le of this; patent; 1

UNTTED STATES PATENTS Name s Date 1,457,745 Norris a. June 5, 1923 1,855,939 Collins Apr. 26, 1932 1,900,852 Kuppersmith Mar. 7, 1933 n 2,339,708 Long, Jan. 18, 1944 Albrechtet al. Aug. 7, 1945

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