Unknown

Abstract

The invention relates to a clamp for use in manufacturing automobile bodies for the automotive industry that is used to clamp and hold metal plate components in place. It is demonstrated how a parallel movement of a pivotal clamping lever is defined with just one component, using simple means.

Claims

1. A clamp for use in manufacturing automobile bodies for the automotive industry that is used to clamp and hold metal plate components in place, which has a chuck and a pneumatic or electric drive dedicated to the chuck, wherein the drive moves a rod-shaped actuator in opposing vertical directions (C D), wherein the actuator pivots an operating lever inside the chuck-within a predefined angular range about a pivot axle in the chuck at its end, the longitudinal axis of which is orthogonal to the longitudinal axis of the rod-shaped actuator, and the operating lever is also pivotally connected to a force-transferring arm by a force-transferring arm pivot axle at its end opposite the pivot axle, and the force-transferring arm pivots a clamping arm support axle that can move in opposing vertical directions (T-V) in the chuck, and the operating lever is flat on the side facing the end of the chuck and forms a two-armed lever at the upper end of the movement of the rod-shaped actuator with a thrust bearing in the chuck when it is moved downward (V), and the clamping arm exerts a constant or nearly constant clamping force on the metal plate component that is to be clamped in place over a clamping area to the end of the clamp when it moves downward (V), parallel to the upward movement (C) of the rod-shaped actuator, when it comes in contact with the metal plate component, wherein the operating lever has an integrally formed cam-shaped actuating lobe on its flat side facing the thrust bearing in the chuck, which rises smoothly and gradually from the flat side-toward the force-transferring arm pivot axle, and imposes a vertical movement (V) on the force-transferring arm and the clamping arm support axle in the chuck-when it comes in contact with the thrust bearing, and the force-transferring arm is braced against a pin-like sliding element in one or both halves or parts of the chuck, such that a defined vertical movement (V-T) is obtained, characterized in that the connecting line between the pivotal center of the clamping arm support axle and the force-transferring arm pivot axle forms a straight line in the clamped position, and the extension of this connecting line runs in a straight line through the middle of the thrust bearing.

2. The clamp according to claim 1, characterized in that the sliding element is snapped in place in the recess in the chuck.

3. The clamp according to claim 1, characterized in that the parallel movement (V) of the clamping arm is a few millimeters, e.g. 4 millimeters.

4. The clamp according to claim 1, characterized in that distance (X) between the centers of the thrust bearing and the force-transferring pivot axle when the operating lever is in the clamping position is 18 millimeters, and the distance (Y) between the pivotal center of the force-transferring pivot axle and the cam-shaped actuating lobe is 12 millimeters, and when the clamping arm is open, the distance (X) is reduced to a distance (X1) of millimeters, and the distance (Y) is reduced from 12 millimeters to 8 millimeters.

Description

[0015] The invention is illustratedin part schematicallyin the drawings. Therein:

[0016] FIG. 1 shows a toggle lever clamp that has a clamping arm in the clamping position, partially cut away in the direction of the longitudinal axis;

[0017] FIG. 2 shows the clamp from FIG. 1 in an intermediate position, in which the actuating lobe bears against the thrust bearing;

[0018] FIG. 3 shows an enlargement of a detail from FIG. 1, broken off in part; and

[0019] FIG. 4 shows an enlargement of a detail from FIG. 2.

[0020] The reference numeral 1 refers to a chuck with a dedicated drive unit 2 in the form of a piston-cylinder unit. The drive unit 2 is removably attached to the chuck 1 with threaded fasteners, not shown. A cylinder 3 contains a piston 4 that can slide longitudinally therein in directions C and D, which is sealed therein with sealing elements, not shown. The piston 4 is moved back and forth in the directions C and D by compressed air supplied by a control unit, not shown, connected to the cylinder by air supply lines, also not shown, at the connecting holes 5 and 6.

[0021] A rod-shaped actuator 7 is connected to the piston 4, which may have a telescoping design such that its length can be adjusted (also not shown). The actuator 7 can also be composed of individual parts that can be screwed together to adjust its length by adding or removing segments thereof.

[0022] An electric motor can also be used instead of the piston-cylinder unit for the drive unit 2, which then moves the actuator 7 back and forth in directions C and D.

[0023] In the embodiment shown in the drawings, the actuator 7 passes through a sealing element 8 in the wall of the chuck 1, which also guides the movement of the actuator 7.

[0024] An operating lever 11 is attached by a pivot axle 10 to the end of the actuator 7 in the interior 12 of the chuck 1. The longitudinal axis of the pivot axle 10 is orthogonal to the longitudinal axis 12 of the actuator 7. There is a pivot axle 14 at the end opposite the pivot axle 10 about which the force-transferring arm pivots, the longitudinal axis of which is parallel to the longitudinal axis of the pivot axle 10.

[0025] Rollers extend at both ends of the pivot axle 10 from the operating lever 11, of which only one roller 15 can be seen in the drawing. The rollers are placed in opposing longitudinal grooves in the chuck 1. Only one groove 16 can be seen in the drawing. The longitudinal grooves are formed in halves of the chuck 1 that are placed against one another and held together by removable threaded fasteners, not shown, in a sealed manner, and the parts or halves of the chuck 1 can be sealed against external dust by gaskets, also not shown, or fit tightly against one another along the separating plane.

[0026] The longitudinal grooves 16 have a curve 17 at the top. This curve 17 can also be formed by a series of curves. There is also a protective guard 18 in this part of the groove that is made of a durable plastic, hardened steel, or ceramic material, the surface of which is also curved where it faces the rollers 15. As a result, the clamp does not have a dead center position. The protective guard 18 can also be replaced when it becomes worn. The protective guard 18 is attached to the chuck 1 with threaded fasteners or adhesive.

[0027] A thrust bearing 19 is fixed in place in the interior 12 of the chuck 1 above the operating lever 11 that can rotate about a needle bearing 20. This thrust bearing 19 has a circular cross section orthogonal to its longitudinal axis.

[0028] The thrust bearing 19 has a dedicated actuating lobe 21, integrally formed on the metal operating lever 11, in particular made of a steel alloy, which forms a cam-shaped lobe on the flat side 22 thereof, in the present example in the form of a bead, a cam, or a roller tappet, protruding above the flat side 22.

[0029] In FIG. 4, the operating lever 11 is pushed upward, in the direction C in the drawing, by compressed air supplied to the piston 4 through the connecting hole 6, such that in the position shown in FIG. 4, the actuating lobe 21 bears on the thrust bearing 19, and then slides along it in a further pivotal movement, illustrated in FIG. 3. As a result, a force-transferring arm 23 is pushed downward (as seen in the drawing) with a force-transferring pivot axle 14 in the direction V (see FIG. 3 and FIG. 4), against the return force of a compression spring 25, which also pushes a force-transferring arm support axle 24 downward, in the direction V, counter to the return force of the compression spring 25.

[0030] The clamping arm support axle 24 is supported in a sliding bushing 26 which is supported at opposing side walls 27 and 28 such that it can slide therein. Furthermore, the force-transferring arm 23 is braced against a removable sliding element 29 in a recess on the inside of the chuck 1, such that a defined up and down movement in the direction V-T is obtained.

[0031] The drawings clearly illustrate that a two-armed lever is formed when the actuating lobe 21 on the operating lever 11 bears on the thrust bearing 19, resulting in a large leverage ratio that can be applied to the pivot axle 10, such that the clamping arm 30 pivots about the clamping arm support axle 24 in the directions A and B over a 135 angle in the embodiment shown in the illustration.

[0032] The illustration also shows that the rotational centers of the force-transferring arm pivot axle 14 and the thrust bearing 19 are coaxially above one another in this embodiment (seen in the drawing plane). In a modification of the embodiment shown in the drawings, the central axis of the thrust bearing 19, the rotational axis of the thrust bearing 19 in the present example, can be offset laterally to the rotational center of the force-transferring arm pivot axle 14 to a certain extent.

[0033] The sliding element 29 can be in the form of a pin that is snapped in place in a recess in one or both halves or parts of the chuck 1 (not shown).

[0034] The operating lever 11 forms a toggle bar in the illustrated embodiment, the opposite sides of which are flat.

[0035] All of the pivot axles 10, 14, and 24 for the rod-shaped actuator and the sliding element 29 are made of a metal in the embodiment shown in the drawings, in particular a steel alloy, as is the thrust bearing 19, which can be in the form of a needle bearing, for example.

[0036] The clamping arm support axle 24 protrudes from one or both sides of the chuck 1. The clamping arm 30 is attached to one or both of these ends (with a forked end in the latter case), such that it can be replaced, functionally forming an integral component therewith.

[0037] Unlike in the embodiment shown in the drawings, the cylinder 3 can have a stop valve (not shown), which prevents compressed air from escaping the cylinder 3 when in the clamping position.

[0038] The distance X.sub.1 in the illustrated embodiment is 14 millimeters, and Y.sub.1 is 8 millimeters, and the distance X in FIG. 3 is 18 millimeters, and Y is 12 millimeters.

[0039] The clamping arm 30 is dedicated to a support element in the form of a jaw 31 for the component that is to be clamped thereon.

[0040] The numeral 31 indicates a support element in the form of a jaw for the component that is to be clamped thereon.