JP2541428Y2 - Clamping device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clamping device for clamping a work.

[0002]

2. Description of the Related Art Conventionally, as a clamp device of this type, a cylinder is fixedly mounted on a bracket on which a clamp arm is pivotably pivoted as disclosed in Japanese Utility Model Laid-Open No. 2-114440.
It is known that the piston rod of the cylinder is connected to a clamp arm via a link so that the piston rod can be opened and closed by the expansion and contraction of the piston rod in the cylinder axis direction.

[0003]

By the way, when closing the clamp arm and clamping the work, the clamp arm is closed so that the work is not unclamped even if the supply of fluid to the cylinder is stopped due to a failure. Self-locking is desired. In this case, the link connecting the clamp arm and the piston rod is connected so that the connection between the first pivot pin at one end to the clamp arm and the second pivot pin at the other end to the piston rod is orthogonal to the cylinder axis when the clamp arm is closed. In this case, the clamp reaction force acts on the piston rod at right angles to the piston rod and does not exert a force to push the rod back in the axial direction, thereby providing a self-locking function. However, in this case, the piston rod receives a lateral force due to the reaction force of the clamp, and the seal member provided at the rod insertion portion of the cylinder and the seal member of the piston are forced, and the durability of these seal members is reduced. In this case, a guide groove that is long in the cylinder axis direction is formed in the bracket, and the second pivot pin is slidably fitted in the guide groove, and a clamp reaction force is applied to the bracket via the second pivot pin. Although it is conceivable to make the piston rod receive the second
Since the pivot pin is in sliding contact with the guide groove, the second pivot pin is worn after a certain use, causing play in the guide groove, and the bracket cannot receive the clamping reaction force. SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to provide a device capable of obtaining a self-locking function and reliably receiving a clamp reaction force by a bracket even after long-term use.

[0004]

In order to achieve the above object,
In the present invention, a cylinder is fixedly mounted on a bracket on which a clamp arm is swingably pivoted, and a piston rod of the cylinder is connected to the clamp arm via a link, and the piston rod is extended and retracted in the cylinder axis direction. In a clamp device that opens and closes a clamp arm, the link between the first pivot pin at one end to the clamp arm and the second pivot pin at the other end to the piston rod is orthogonal to the cylinder axis when the clamp arm is closed. And a lock groove into which the second pivot pin fits when the clamp arm is closed is formed in the bracket.

[0005]

In the closed state of the clamp arm, the connection of the first and second pivot pins is orthogonal to the cylinder axis, so that the clamp arm is self-locked to the closed state. At this time, the clamp reaction force acting in the direction orthogonal to the cylinder axis via the link is received by the bracket in the lock groove into which the second pivot pin fits, and no lateral force due to the clamp reaction force acts on the piston rod. Here, the fitting of the second pivot pin into the lock groove is limited to the closed state of the clamp arm, and the second pivot pin does not slide on the lock groove during the opening / closing operation of the clamp arm. Wear of the support pin is suppressed as much as possible, and the second pivot pin fits into the lock groove without play even after long use, and the clamp reaction force is reliably received by the bracket as described above.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the illustrated embodiment, the present invention is applied to a clamp device attached to a jig for suspending a workpiece W. As shown in FIG. An arm-shaped work receiver 3 that comes into contact with the upper surface of the work W is attached to the bracket 2 to be stopped, and a clamp arm 4 that comes into contact with the lower surface of the work W and clamps the work W between the work receiver 3 and the work arm 3 is vertically moved. Pivotably attached to
The clamp arm 4 is opened and closed by a cylinder 5 fixed to the bracket 2.

More specifically, as shown in FIGS. 2 and 3, a pair of side plates 2a, 2a
And boss portions 2b on the inner surfaces of the side plates 2a, 2a.
Boss 2b at the upper end of an L-shaped lever 4a for projecting a clamp arm 4 at its tail end.
b, 2b via a pivot 4b, a cylinder 5 is erected on the upper surface of the bracket 2, and a lower end of a piston rod 5a extending downward along the axis a from the cylinder 5 is levered. The clamp arm 4 is pivotally connected to the lower end of the portion 4a via the link 6 so that the clamp arm 4 is opened downward by the upward contraction operation of the piston rod 5a and closed upward by the downward extension operation of the rod 5a. did.

The link 6 is pivotally attached to a lever 4a via a first pivot pin 6a at a forked portion at one end.
In the forked portion at the other end, it is pivotally connected to the piston rod 5a via the second pivot pin 6b. When the clamp arm 4 is in the closed state, the connection b between the pivot pins 6a and 6b is connected as shown in FIG. The state was set so as to be orthogonal to the axis a of the cylinder 5. According to this, the clamp reaction force acting on the connection from the clamp arm 4 via the link 6 does not act as a force for pushing up the piston rod 5a, and the clamp arm 4 is self-locked to the closed state.

As shown in FIG. 4, both ends of the second pivot pin 6b protrude outside the both side plates 2a, 2a of the bracket 2, and the both side plates 2a, 2a are shown in FIG. As described above, when the clamp arm 4 is closed, the lock groove 7 in which both ends of the second pivot pin 6b fit is formed, the clamp reaction force is received by the bracket 2 in the lock groove 7, and the piston rod 5a receives the clamp reaction force. The lateral force caused by force is not applied. In each side plate 2a, a groove 8 extending above the lock groove 7 is formed.
The second pivot pin 6b does not slide on the groove 8 when the piston rod 5a expands and contracts.

[0010] In the figure, 9 is a locking piece for retaining the pivot 4b,
10 is a locking pin for retaining the first pivot pin 6a, 1
Reference numerals 1 and 12 denote washers and split pins mounted on both ends of the second pivot pin 6b.

[0011]

As is clear from the above description, according to the present invention, the clamp arm can be self-locked in the closed state, and the pivot pin for the link connecting the clamp arm and the piston rod to the piston rod is mounted on the bracket. The bracket can receive the clamp reaction force by fitting it into the lock groove formed in the above, and since the pivot pin fits into the lock groove only in the closed state of the clamp arm, Wear due to sliding contact of the pivot pin during opening and closing operation is prevented, the pivot pin fits into the lock groove without play even after long use, and the clamp reaction force is securely received by the bracket and the piston rod is clamped against the piston rod. No lateral force is exerted by the force, and the seal member for the piston rod or the piston of the cylinder is not overloaded and the durability is improved.

[Brief description of the drawings]

FIG. 1 is a side view of an example of the device of the present invention.

FIG. 2 is an enlarged cut-away side view of the main part.

FIG. 3 is a sectional view taken along line III-III of FIG. 2;

FIG. 4 is a sectional view taken along the line IV-IV of FIG. 2;

[Explanation of symbols]

 2 Bracket 4 Clamp arm 5 Cylinder 5a Piston rod 6 Link 6a First pivot pin 6b Second pivot pin 7 Lock groove

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-57-132983 (JP, A) JP-A-2-114440 (JP, U) JP-A-49-53468 (JP, U) JP-A-3 62788 (JP, U)

Claims (1)

(57) [Scope of request for utility model registration] 1. A cylinder is fixedly mounted on a bracket on which a clamp arm is pivotably pivotally connected, and a piston rod of the cylinder is connected to the clamp arm via a link to extend and retract the piston rod in the cylinder axis direction. In the clamp device in which the clamp arm is opened and closed, the connection of the link between the first pivot pin at one end to the clamp arm and the second pivot pin at the other end to the piston rod is orthogonal to the cylinder axis when the clamp arm is closed. And a lock groove in which the second pivot pin fits when the clamp arm is closed in the bracket.