US2271041A - Clamping device - Google Patents

Description

F. J. s'rucKER-r CLAMPING DEVICE Filed April 13, 1940 Jan. 27, 1942.

Patented Jan. 27, 1942 UNITED i STATES PATENT oFFlcE Felix J, Stuckert, Wauwatosa, Wis., assigner to. Briggs & Stratton Corporation, Milwaukee, Wis., a corporation of Delaware f Application April 13, 1940, seriaiNo. 329,485 9 claims. I(c1. :io-'60) s in one continuous operation of the actuating This invention relates generally to clamps of the type employed to securely hold work to a supporting surface while machining operations are performed on the work.

At present various types of clamps are employed for this purpose, the most common of which are the strap and angle iron types. Strap type clamps employ a harto bridge the space between an article on a work table and ablock placed on the table adjacent to the article and effect clamping by tightening a stud or bolt anchored in the work table and extending through the strap. y

In the angle iron type the strap is angle shaped, and has one leg or iiange of the angle abutting the supporting surface while the end of its opposite flange engages the Work on the support. In this form the clamp is also tightin mind, this invention has as a general object.

to provide a clamping device for the purpose described which may be quickly operated to releasably clamp work to a support without entailing tightening of screws or removal of the clamp from vthe supporting surface.

Another object of this invention resides in providing a clamping device of the character described with a clamping lever projectable manually to and fromk an loperative clamping position with respect to an article to be clamped.

Still another object of the invention resides in the provision of a clamping device-of the character described with a pivoted clamping lever which may be projected bodily outwardly of the device to an operative position over work to be clamped and thereafter tilted on its pivot toward the work in a clamping relationship therewith.

A further object of this invention is to provide a manually operable clamping device of the character described with actuating means adapted to successively project the clamping lever outwardly of the device to an operative position over the Work to be clamped and then force the lever into clamping engagement with the work means.

With the above and other objects .in view which will appear as the description proceeds, this invention resides in the novel construction, combination and arrangement of parts substantially as hereinafter described, and more particularly defined by the appended claims, it being understood that such lchanges in the precise embodiment of the hereindisclosed invention may be made as come within the scope of the claims. A` The accompanying drawing illustrates one complete example yof the physical embodimentA of the inventionconstructed in accordance with the best vInodev so far devised for the practical application of 'the principles thereof, and yin which:

Figure 1 is a device of thisA invention vwith broken away and in section; y

F'gure 2 is a longitudinal sectional view illustrating the inactive position of the clamping lever of the device;

Figure`3 ifs va sectional view similar to Figure 2 illustrating the active position of the clamping lever of the device; f l

' Figure 4 is a transverse sectional view taken through Figure'2 on the plane of the line 4-4 andl f Figure 5 is ahfragmentary perspective view illustrating portions of the clamping device. Referring now particularly to the accompanyin 'g drawing in which like numerals indicate like parts, the numeral I Il vvgenerally designates the perspective view-ofl the clamping a part thereofr clamping device of this invention. As is customary, thecl'ampi'ng Vdevice is used to rmly hold an article of workindicated in construction lines asv at II to the work table o f the machine which'is tc perform the machining operations on the article. The clamping device may be used in conjunction with a work locating fixture or template I2, or it mayfbeused merely to hold the work indiscriminately to the work table.

As illustrated, the clamping device I0 comprises a supporting structurev I3' which'includes a flat base I4 andspaced arms' I5 and I6 projecting'upwardly from the front end of the base. A clamping lever I1 is positioned between the arms and comprises aY substantially T-shaped member having its forward end slidably confined between the arms and its T-shaped rear end overlying the base.

The clamping'lever is slidably supported above the' top'face of the ibase by means of a pair of adjustable screwsl I passing through the op- The clamping lever I1 is yieldingly maintained 'I in a rearward or inactive position over the base by a pair of compression springs 20 disposed on opposite sides of the clampingl portion of the 1' clamping lever and having one end received in wells 2| in the rear edges of the arms I5 and I6. The other ends of the springs are received in recesses 22 in the T-shaped head of the clamping lever so that-the springs at all times tend to slide the clamping lever rearwardly across the base.

A centrally located lug 23 at the rear of the base projects up into the path of rearward sliding motion of the clamping lever to, limit the same. For this purpose, the T-shaped head is provided with a notch 24 to receive the lugtherein in its rearward inactive position. Engagement between the lug and the bottom of the notch limits rearward sliding motion of the clamping lever, while the sides of the lug engage with the side walls of the notch to preclude lateral shifting of the clamping lever when retracted.

rTo effect forward propulsion of the clamping lever I1 an actuator including a cam-like lpusher 26 is provided. The pusher 26 is supported'between the arms I5 and I6 from a hexagonal shaft 21 having a circular bearing portion 28 at one end thereof journalled in the arm I6 and carrying a bushing 29 at its opposite hexagonal end which is journalled in the arm I5. The camlike pusher is, therefore, drivingly connected with the hexagonal shaft 21 for rotation therewith.

As illustrated, the pusher 2li is notched as at 3D to provide a shoulder 3| at one end of the notch. As illustrated, the lower portionof the cam-like pusher member projects into a recess 32 Vcut into the side of theclamping lever so as to provide an abutment `33 facing the pusher shoulder 3| and in the path of the shoulder during rotation of the pusher member. Such rotation is imparted to the hexagonal shaft 21 and, consequently, the pusher member, by means of a hand lever 35 having a hexagonal hole 36 therein engageable over a hexagonal hub 31 on the bushing member 29. Consequently rotation of the hand lever in a clockwise direction as viewed in Figures 2 and 3 engages the shoulder 3| of the pusher member with the abutment 33 at the forward end of the recess in the side of the clamping lever and slides the clamping lever forwardly to a position in which its front en is above the work or article I I. i

When the clamping lever is thus extended a cam 39, which may be formed either integrally with the pusher member 26 as shown or as a separate part on the shaft so as to be rotatable therewith is employed to tilt the forward end of the clamping lever downwardly-toward the base I4 into clamping engagement with the article l I. For this purpose, the cam 39 is provided with a concentric surface 46 with which the clamping lever normally engages,` and an eccentric surface 4I which is brought into engagement with the clamping lever during clockwise rotation of the shaft and after the clamping lever has been fully projected by the pusher 2S.

In this manner, one continuous motion of the hand lever to rotate the pusher and cam in a clockwise direction successively effects forward propulsion of the clamping lever with a translating motion and then tilting motion thereof toward the base and into clamping engagement with the work or article I I.

The motion imparted 4to the clamping lever bythe cooperating pusher and cam actuating means is desirableiin that it enables clamping of theV work without any danger of the clamping lever shifting the same with respect to the work table or fixture upon which the work is positioned.

. .The clamping lever I1, it is to be noted, is at all times maintained in engagement with the cam 39 by the action of the leaf spring I9, which engages the clamping lever at a point such as to exert a turning moment on the clamp about the point of contact between the clamping lever and the periphery of the cam. Thus, the ends of the screws I8 are maintained in contact with the top face of the base and cooperate with the leaf spring I9 to freely tiltably and slidably mount the clamping lever. Y

The extent of forward propulsion of the clamping lever |1 is, of course, determined by the diameter or throw of the pusher member 26.

The actuating means for the clamping lever I1 is designed to operate the same during rota.- ticn of the handlever through an angle of approximately 90. Y Y y The forward end of the clamping lever is preferably provided with atoe 42 projectingV from the underside of its forward end to facilitate clamping rough castings and to enable proper engagement ofv the `clamping lever with the work in the event the article or jig therefor is provided with a rim or rib at its top periphery.

Release ofthe clamping device from the Work upon completion of the machining operations is effected by an opposite or counterclockwise rotation of the hand lever 35 and consequently the actuating members 26 Yand 39. Thus,Y at the start of counterclockwise rotation of the lever the pressure of the clamping lever on the article I I is gradually decreased inasmuch as such rota.- tion of the cam 39 decreases the eccentricity of its periphery. Further rotation in this direction causes the-shoulder 3| on the pusher member to again enter the recess 32. At this instant, the concentric surface of the cam 39 is brought into engagement' with the clamping lever Aand the clamping lever is elevated to its fully raised position ready for retraction.

While the compression springs 20 at all times exert a forceon theclamping lever tending to retract and maintain the same engaged with the pusher member 26, such action isprevented during release of the clamp and whenever the shoulder 3| is out of the recess 32 by the action of the leaf spring I9 which is compressed to va greater extent as long as the eccentric surface of the cam 39 is in contact with the upper face of the clamping lever. Thus a substantial friction is maintained at the point of contact between the clamping lever and the eccentric cam surface 4I which is sufficient to prevent the compression springs 26 from retracting the clamping lever until such vtime as the shoulder 3| of the pusher member'l again enters the recess A32 and the concentric surface of the cam engages the clamping lever.i w-

As will ybe readily understood, the clamping device of this invention may be quickly adjusted toward and from the work table to accommodate articles of diiferent thicknesses, and as shown, a shim 43 or a number of shims may be inserted between the work table and the bottom of the base of the clamping device for this purpose.

Tapped holes are provided in the bottom of the base to receive the threaded endsof screws 43 which detachably secure the clamping device to thework table of the machine as illustrated, or

to the Xture I2 if provision for the clamping device is made therefor.

While the clamping device has been illustrated "in use on a horizontal Work table it is to be From the foregoing description taken in conu nection with the accompanying drawing, it will be readily apparent that this invention provides a particularly eicient clamping device which is capable of rapid operation and which does not entail the tightening or loosening of screws by an operator during use thereof.

What I claim as my invention is:

1. In a clamping device of the character described: a clamping lever; means for movably supporting the clamping lever in spaced relation to a work supporting surface; and a manually movable actuator for moving said clamping lever successively outwardly of its support across said surface and downwardly onto an article on the work supporting surface to clamp work thereto during movement of the actuator in one direction.

2. In a clamping device of the character described: a base adapted to be secured to a work support adjacent to work thereon; a clamping lever; means supporting the clamping lever in spaced relation to the base'and for movement across and toward the base; a single pivoted hand lever; and actuating means driven by the hand lever for moving the clamping lever successively outwardly across the base to a projected position in which a portion of the clamping lever overlies the work on the support and toward the base to eifect clamping of the work between the work support and said portion of the clamping lever during one continuous motion of the hand lever.

3. In a clamping device of the character described: a base adapted to be secured on a work support adjacent to work thereon; a clamping lever; means supporting the clamping lever; above the base for movement across and toward the hase; a single hand lever mounted from the base for pivotal motion; actuating means driven by the hand lever operable in one continuous motion of the hand lever to move the clamping lever outwardly across the base to a projected position vfor rotation about an axis spaced above the base; actuating means rotatable with the shaft and positioned between said arms; a slidable clamping lever overlying the base and having one end portion thereof disposed in the space between said arms and between the base and said actuating means; means biasing the clamping lever to 'a retracted position spaced above the base and engaging vsaid actuator; an abutment on the 4clamping lever; a shoulder on said actuating means engageable with the clamping lever abutment during rotation of the shaft in one 'direction for sliding the clamping lever across the base to a projected position in which said end portion of the clamping `lever overhangs the base; and means on said actuatingy means operable subsequently to such outward projection of the clamping lever and during continued rotation of the shaft in the same direction for forcing said clamping lever end portion toward the base ina clamping action. f n

5. In a clamping device of thecharacter described: a base; a substantially T-shaped clamping lever; an vadjustable abutment carried by each end of the Tportion of the clamping lever in a position engaging the top face of the base so as to readily adjustably hold the T portion of the clamping lever va distance above the base; resilient means engaging the end of the clamping lever opposite its T portion and yieldingly urging said opposite end away from the base, said means cooperating Ywith the abutments to mount the clamping lever for movement across the base and for movement of said opposite end thereof toward the base about an axis defined by the points of engagement of the adjustable abutments with the top face of the base; rotatable actuator mechanism for the clamping lever; a hand lever for rotating the actuator mechanism means on the actuator mechanism operable to move the clamping lever across the base to a projected position upon motion of the hand lever in one direction to rotate the actuator mechanism; and a cam forming a part of the actuator mechanism operable after completion of the motion of the clamping lever across the base and during continued motion of the hand lever in said direction to depress said opposite end ofthe clamping lever about the axis dened by the points of engagement between said abutments and the base.

6. In a clamping device of the character described: a base; .spaced apart arms extending upwardly from the base; a substantially T-shaped clamping lever overlying the base with its stem disposed between said arms; cooperating means supporting the clamping lever above the base for movement across and toward the base; a compression spring on each side of the stem of the T-shaped clamping lever, each of said springs being confined between the side of the arm and the end of the T at opposite sides of the stem so as to yieldingly urge the T-shaped clamping lever in one direction with respect to the base; means on the base engageable with the clamping lever to limit movement thereof in said direction; and a rotatable actuator for the clamping lever operable upon rotation in a single direction to successively effect movement of the clamping lever across the base in the opposite direction and depression of the lever toward the base.

7. In a device of the character described: a base; spaced apart arms extending upwardly from the base; a clamping lever; means supporting the clamping lever above the base for movement across and toward the base; a shaft rotatably journalled in said arms, said shaft having a medial portion of multiangular cross section; actuator mechanism on said portion of the shaft between the arms so as to be driven by the shaft; a hand lever mounted on an extension of the shaft outwardly of one of said arms of multiangular cross section for imparting rotation to the shaft and said actuator mechanism, said actuator mechanism including means for moving the clamping lever across the base and subsequently toward the base during rotation of the hand lever in a single direction; and means detachably securing the hand lever to the extension of the shaft whereby the hand lever is readily removable and adjustable angularly on said multiangular extension.

8. In a clamping device of the character described: a rigid supporting structure including a pair of spaced apart arms; a movable clamping lever having a portion at its forward end received between said arms vto be guided for movement thereby; an abutment on each side of the rear end portion of the clamping lever, each of said abutments being adjacent to one edge of each arm; a compression spring disposed at each side of the clamping lever and confined between each of the arms and the abutments of the clamping lever adjacent thereto so as to yieldingly urge the clamping lever in one direction with respect to the arms; an actuator movably carried by the arms in the space therebetween; means carried by the supporting structure for yieldingly urging the clamping lever toward engagement with said actuator; and means on the actuator operable upon motion thereof in one direction to move the clamping lever in a direction against the force of said compression springs and subsequently force the clamping lever in a vdirection away from the actuator against its yielding means.

9. In a clamping device of the character described: a supporting structure including a base adapted to be secured to a work table adjacent to work thereon and spaced apart arms extending upwardly from the base; a movable clamping leverhaving a portion at its forward end received between said arms to be guided thereby for movement across and toward the base; actuator mechanism movably carried by theA arms in the space therebetween; a hand lever carried by the supporting structure for imparting motion to the actuator mechanism; means on the supporting structure for yieldingly urging the clamping lever toward engagement with the actuator mechanism and spaced away from the base; means on the actuator mechanism operable to move the clamping lever across the base to a position in which its forward end portion is projected and overlies the work on the table and to subsequently force the clamping lever toward the base-and into clamping relationship with the work on the table upon motion of the actuator mechanism produced by motion of the hand lever in one direction; and a toe projecting from the underside of the forward end portion of the clamping lever engageable with the work during motion of the clamping lever toward the work to conne contact between the clamping lever and the work to a small area of the clamping lever.

FELIX J. STUCKERT.

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