JP2645725B2 - Clamping device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD OF THE INVENTION

The present invention relates to a clamp device for clamping a workpiece that is positioned and conveyed on a carriage in an automatic assembly line or the like.

[Prior art]

2. Description of the Related Art Conventionally, for example, in an automatic assembly line of an automobile, a work such as an engine is transported by a cart (work table), and various processing steps or assembling steps are performed in respective stations. In each station, it is necessary to position the work at a predetermined position, but conventionally, a clapping device is provided in each station, and after the bogie stops in the station, the work is clamped by the clamp device. It is supposed to do. As a drive source of the clamp device, a pneumatic cylinder or a hydraulic cylinder capable of performing so-called push-off is often used. However, in recent years, the so-called skit method is often adopted, in which a clamping device is provided on the cart itself, the workpiece is transported while being clamped to the cart, and only the cart is positioned at each station. Have been. In the skit method, a clamp device provided on a cart and a drive source for driving the clamp device, for example, a pneumatic cylinder, or an air source for supplying compressed air to the pneumatic cylinder, are separated during transportation. Become.

[Problems to be solved by the invention]

Therefore, when the carriage is being transported between the stations, the driving force that generated the clamping force on the clamping device is not applied. Therefore, conventionally,
There has been a problem in that the clamping force of the clamping device is reduced, the work is loosened, and as a result, the clamp is disengaged and the work is displaced, and in some cases, the work is dropped from the carriage. The present invention has been made in view of the above problems, and has as its object to provide a clamp device that can maintain a clamping force for clamping a work even when a driving source, an air source, or the like is disconnected.

[Means for Solving the Problems]

The present invention solves the above-described problems, in order to clamp a work between a work table and a clamp claw rotatably mounted on a clamp shaft, one end of the clamp claw being attached to one end of the clamp claw. A link member rotatably connected via a parallel shaft pin, a drive rod rotatably connected to the other end of the link member via a shaft pin parallel to the clamp shaft, and the drive rod A guide member for guiding the reciprocating movement in a tangential direction of a circle around the clamp shaft, and a guide member provided on the drive rod,
An engagement portion for pushing or pulling the drive rod by a drive source, and a restriction for restricting movement of the drive rod in one direction at a dead position where an angle formed between the drive rod and the link member is substantially a right angle. And a resilient member provided to regulate movement of the drive rod in the other direction at a dead position of the drive rod and to urge the clamp claw in a clamping direction. Is done. The drive rod is pushed or pulled in the axial direction by a pneumatic cylinder, a hydraulic cylinder, or the like, and moves at its moving end, where the movement is regulated by a regulating member and stopped. With the movement of the drive rod, the link member and the clamp pawl rotate, and the clamp pawl clamps the work. In a state where the driving rod is stopped by being restricted by the restricting member, the driving rod is at a dead position where the angle between the driving rod and the link member is substantially perpendicular. At the dead position, the clamping force of the work by the clamp claws is almost maximum. In the dead position, the movement of the drive rod is restricted to one side by a restricting member, and the movement to the other side is restricted by an elastic member, and the elastic member is urged by the elastic member in a direction in which the clamp claws are clamped. Therefore, the clamped state is always maintained, and the clamp force is maintained at a substantially maximum state.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a front sectional view of a clamp device 1 according to an embodiment of the present invention, and FIG. 2 is a plan view of the clamp device 1 of FIG. The clamp device 1 includes a frame 2 bent in a U-shape in plan view, a clamp claw 4 rotatably attached to a clamp shaft 3 provided on the frame 2, A link member 6 rotatably connected via a pin 5, a drive rod 8 rotatably connected via a shaft pin 7 to the other end of the link member 6, and a drive rod 8 at its upper end position (dead end). From the position). Both shaft pins 5, 7 are parallel to each other and parallel to the clamp shaft 3. The frame 2 includes a back portion 2a and side portions on both sides of the back portion 2a.
2b, 2b, and clamp shafts 3 on both side portions 2b, 2b on both sides.
Guide grooves 10, 10 are provided extending in a tangential direction (vertical direction in FIG. 1) around the circumference centered at. The drive rod 8 is provided at both ends in the axial direction of the shaft pin 7 with rollers 11 that are fitted into the guide grooves 10 and that can move along the guide grooves 10. , 2b, a guide block 12 having a bush 12a through which the drive rod 8 slidably penetrates is attached. The guide rod 10 and the guide block 12 allow the drive rod 8 to reciprocate up and down linearly with its axis aligned with the center line of the guide groove 10. In the state shown by the solid line in FIG.
The drive rod 8 is in contact with the upper end 10a of the
When the drive rod 8 is lowered from this state, the link member 6 is lowered while rotating as the shaft pin 7 is lowered, and the clamp claw 4 is rotated rightward about the clamp shaft 3. Away from the work W. Then, when the shaft pin 7 reaches the position P2, the link member 6, the shaft pin 5, and the clamp claw 4 are at the positions indicated by the chain lines in FIG. 1, and the work W is released from being clamped. In the state shown by the solid line in FIG. 1, the roller 11 is in contact with the upper end 10a of the guide groove 10, but the angle α between the drive rod 8 and the link member 6 at that time is a right angle. . The position of the drive rod 8 at this time is the dead position P1. In the clamped state, the link member 6 receives a force in the compression direction due to the reaction force received by the clamp claw 4 from the workpiece W.
It acts on the drive rod 8 or the guide groove 10. However, when the angle α is a right angle (when it is at the dead position P1), the force received by the link member 6 acts only on the guide groove 10, and hardly acts on the drive rod 8 in the axial direction. The leaf spring 13 attached to the rear part 2a of the frame 2
When the drive rod 8 is at the dead position P1, the drive rod 8 is engaged with the step 8a formed on the slope of the drive rod 8 and acts to push up the step 8a from below. This allows the leaf spring
13 increases or holds the clamping force by the clamp claw 4 and regulates the drive rod 8 from lowering due to its gravity or vibration. An engagement member 14 for ascending or descending the drive rod 8 by engaging with a pneumatic cylinder (not shown) provided outside is attached to a screw portion 8b provided at a lower end portion of the drive rod 8. The clamp device 1 configured as described above is attached to an end of the work table C with a bolt or the like to clamp the work W placed on the upper surface C1 of the work table C. Next, the operation and use of the clamp device 1 will be described. First, when the work table C is at a station (not shown), a pneumatic cylinder (not shown) is engaged with the engagement member 14 to drive the drive rod 8 upward, thereby bringing the work into a clamped state shown in FIG. W is clamped by the clamp claws 4. At that time, immediately before the drive rod 8 reaches the dead position P1, if the step 8a gets over the leaf spring 13, the elastic force of the leaf spring 13 acts to push the step 8a upward, and this causes the work W to be clamped. Increase power. Thereafter, the work table C leaves the above-mentioned station, and the clamp device 1 is separated from the pneumatic cylinder. However, since the driving rod 8 is at the dead position P1 as described above, and the step 8a is pushed by the leaf spring 13, , The clamping force is maintained, and the work W is not loosened. When removing the work W from the work table C, the piston rod of the pneumatic cylinder (not shown) is engaged with the engaging member 14 at an appropriate station (not shown), and the drive rod 8 is driven downward. As a result, the leaf spring 13 is bent and disengaged from the step 8a of the drive rod 8, the drive rod 8 is lowered, and the clamp claw 4 is moved to the position P2 indicated by a chain line in FIG.
Until the workpiece W is released. In the above-described embodiment, the drive rod 8 can be reciprocated by moving the roller 11 along the guide groove 10. However, the roller 11 and the guide groove 10 may be replaced with another appropriate guide member. Is also good. Although the engaging member 14 and the external pneumatic cylinder are detachably engaged with each other, the pneumatic cylinder is connected to the screw portion 8b of the driving rod 8 and attached to the clamp device 1, and the piping of the pneumatic cylinder is disconnected. You may do so. Further, instead of the pneumatic cylinder, a hydraulic cylinder, an electric cylinder, or another driving source may be used, and a wire or the like may be used for transmitting the driving force. In the above embodiment, a compression spring, a tension spring, an air spring, or another elastic member may be used in place of the leaf spring 13. As the link member 6, a strong compression spring may be used. An appropriate regulating member may be arranged at the upper end 10a. The positions of the upper end portion 10a and the leaf spring 13 can be provided at appropriate positions where the angle α is near a right angle. In the above-described embodiment, the work W is clamped by pushing the drive rod 8. However, the work W may be clamped by pulling the drive rod 8.

【The invention's effect】

According to the present invention, in the dead position, the movement of the driving rod is regulated by the regulating member and the elastic member, and even when the driving source or the air source is disconnected, it is possible to maintain the clamping force for clamping the work. it can. In addition, in the dead position, the movement of the drive rod to the other side is restricted by the elastic member, and the elastic member urges the clamp claw in the clamping direction.
There is no fear that the clamped state is released even when a large vibration is applied.

[Brief description of the drawings]

FIG. 1 is a front sectional view of a clamp device according to an embodiment of the present invention, and FIG. 2 is a plan view of the clamp device of FIG. 1 Clamping device, 3 Clamp shaft, 4 Clamp claw, 5, 7 Shaft pin, 6 Link member, 8 Driving rod, 8a Step, 8b Screw ( Engaging portion), 10: guide groove (guide member), 10a: upper end (restriction member), 11: roller (guide member), 13: leaf spring (elastic member), 14: engaging member (Engagement part), P1 ... dead position, W ... work, C ... work table.

Claims (1)

(57) [Claims] A clamp claw rotatably mounted on a clamp shaft for clamping a work to a work table; one end of which is connected to one end of the clamp claw via a shaft pin parallel to the clamp shaft; A link member rotatably connected, a drive rod rotatably connected to the other end of the link member via a shaft pin parallel to the clamp shaft, and a drive rod centered on the clamp shaft. A guide member for guiding a reciprocating movement in a tangential direction of a circumference to be provided; an engaging portion provided on the drive rod for pushing or pulling the drive rod by a drive source; A regulating member that regulates movement of the drive rod in one direction at a dead position where an angle between the drive rod and the link member is substantially a right angle; and a drive rod at a dead position of the drive rod. While restricting movement in the other direction, the clamping device comprising a, an elastic member provided so as to bias in a direction to clamp the clamp jaws.