Clamping device

Abstract

The present invention provides a clamping device that does not reduce the amount of oscillation of the connecting member even when the axial length of the cylinder body is shortened. [Solution] The link mechanism 16 consists of a connecting body 17 attached to the piston rod 8, a first link member 18 with one end rotatably connected to a first mounting portion 17a protruding from the opposite side of the support portion 13 of the cylinder body 2 of the connecting body 17, and a second link member 19 with one end rotatably connected to a second mounting portion 17b protruding from the support portion 13 side of the connecting body 17 of the cylinder body 2. By moving one end of the second link member 19 between the piston rod 8 and the support portion 13 via the connecting body 17 using the piston rod 8, it is possible to increase the amount of oscillation of the connecting member 14 relative to the travel distance L of one end of the second link member 19.

Description

[Technical Field]

[0001] The present invention relates to a clamping device in which a piston accommodated in a cylinder body is reciprocated by pressurized fluid supplied from a pair of piping ports provided in the cylinder body, a piston rod is connected to the piston, one end of a connecting member is rotatably connected to a support portion provided on the cylinder body, and a clamp arm rotatably connected to the other end of the connecting member is moved between a clamping position abutting against a clamping surface of a workpiece and an unclamping position located below the clamping surface of the workpiece by a link mechanism attached to the reciprocating piston rod. [Background Art]

[0002] In the above clamping device, the clamp arm does not interfere with the workpiece even when the workpiece is loaded and unloaded while the clamp arm is moved to the unclamping position. Further, the clamping device is provided with a link mechanism that makes the movement locus of the clamp arm compact so that the clamping device can be installed in a narrow space. As disclosed in Citation 1, the link mechanism is composed of a connecting body attached to the piston rod, a first link member one end of which is rotatably connected to a first attachment portion of the connecting body protruding toward the opposite side of the support portion of the cylinder body, and a second link member one end of which is rotatably connected to the connecting body, wherein the other end of the first link member is rotatably connected to the rear end of the clamp arm, and the other end of the second link member is rotatably connected to the connecting member. Such a structure is known in the art. [Prior Art Documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent No. 3608672 [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] As shown in Figures 4 and 5, in the link mechanism 100 described above, when one side of the second link member 103 moves along the axis CL of the piston rod 101 via the connecting body 102 by the piston rod 101, the other side of the second link member 103 swings the connecting member 104 to which it is connected. This swinging of the connecting member 104 causes the clamp arm 105 to move between the clamp position and the unclamped position. When installing a conventional clamping device equipped with the link mechanism 100 described above into a jig, a jig base 107 of sufficient thickness to mount the cylinder body 106 of the clamping device is required, which increases the overall weight of the jig. Additionally, a clamping surface height P corresponding to the travel distance of the piston rod 101 is required, which increases the height of the clamping device. Therefore, as shown in Figure 6, one might consider shortening the travel distance of the piston rod 101 (the travel distance of the connecting body 102) in order to reduce the size of the cylinder body 106 of the clamping device. However, if the travel distance of one of the second link members 103 connected to the connecting body 102 is shortened, the amount of oscillation of the connecting member 104 decreases, causing the unclamping position of the clamp arm 105 to rise. Consequently, when inserting or removing the workpiece W, the workpiece W may interfere with the clamp arm 105. Therefore, in view of the above problems, the object of the present invention is to provide a clamping device that does not reduce the amount of oscillation of the connecting member even when the axial length of the cylinder body is shortened. [Means for solving the problem]

[0005] The present invention provides a link mechanism comprising a connecting body attached to a piston rod, a first link member with one end rotatably connected to a first mounting portion protruding from the opposite side of the support portion of the cylinder body of the connecting body, and a second link member with one end rotatably connected to a second mounting portion protruding from the support portion side of the cylinder body of the connecting body. The other end of the first link member is rotatably connected to the rear end of the clamp arm, and the other end of the second link member is rotatably connected to the connecting body. The piston rod moves one end of the second link member between the piston rod and the support portion via the connecting body. [Effects of the Invention]

[0006] In this invention, the link mechanism consists of a connecting body attached to a piston rod, a first link member with one end rotatably connected to a first mounting portion protruding from the opposite side of the support portion of the cylinder body of the connecting body, and a second link member with one end rotatably connected to a second mounting portion protruding from the support portion side of the cylinder body of the connecting body. The other end of the first link member is rotatably connected to the rear end of the clamp arm, and the other end of the second link member is rotatably connected to the connecting body. By moving one end of the second link member between the piston rod and the support portion via the connecting body using the piston rod, it becomes possible to increase the amount of oscillation of the connecting body relative to the travel distance of one end of the second link member. As a result, even if the travel distance of one end of the second link member is reduced compared to conventional designs, the oscillation of the connecting body makes it possible to move the clamp arm between the clamp position and the unclamped position. Therefore, by shortening the travel distance of the piston rod and reducing the size of the cylinder body, the thickness of the jig base can be reduced, resulting in a lighter overall jig, and the height of the clamping surface corresponding to the travel distance of the piston rod can be lowered, making it possible to miniaturize the clamping device. [Brief explanation of the drawing]

[0007] [Figure 1] This diagram shows the clamping position of the clamping arm of the clamping device of the present invention. [Figure 2] This is a second-view perspective of Figure 1. [Figure 3] Figure 1 shows the clamping arm of the clamping device in the unclamped position. [Figure 4] This is a diagram showing a conventional clamping device. [Figure 5] Figure 4 shows the clamping arm of the clamping device in the unclamped position. [Figure 6] This figure shows the clamping device in Figure 4 when the travel distance of the piston rod is shortened. [Figure 7] This diagram shows the other connection position of one of the second link members. [Modes for carrying out the invention]

[0008] The cylinder body 2 of the clamping device 1 shown in Figure 1 is formed by closing both ends of a cylinder tube 3 with end members 4 and 5, thereby creating a cylinder chamber 6 within the cylinder tube 3. An annular piston 7 is housed in the cylinder chamber 6 so as to be movable in the axial direction, and the piston 7 divides the cylinder chamber 6 into first and second cylinder chambers 6a and 6b. A piston rod 8 that protrudes outward from the cylinder body 2 is connected to the piston 7. A portion of the piston rod 8 is guided through a through hole 9 drilled in the cylinder body 2. The cylinder body 2 is provided with a pair of pipe connection ports 10a and 10b for supplying pressurized fluid to the respective cylinder chambers 6a and 6b from the outside. The cylinder body 2 is also provided with a first flow path 11 that connects one connection port 10a to the first cylinder chamber 6a, and a second flow path 12 that connects the other connection port 10b to the second cylinder chamber 6b. As a result, the pressurized fluid supplied and discharged between the pair of connection ports 10a and 10b and the first and second cylinder chambers 6a and 6b causes the piston 7 to reciprocate within the cylinder chamber 6.

[0009] A support portion 13 is erected at the upper end of the cylinder body 2. One end of a connecting member 14 is rotatably connected to the support portion 13. The other end of the connecting member 14 is rotatably connected to the middle part of a clamp arm 15 that clamps the workpiece W. When one end of the connecting member 14 is pivoted from side to side, the clamp arm 15 moves up and down.

[0010] A link mechanism 16 is attached to the mounting portion 8a of the piston rod 8. The link mechanism 16 consists of a connecting body 17 attached to the mounting portion 8a of the piston rod 8, a first link member 18 whose one end is rotatably connected to a first mounting portion 17a that protrudes from the opposite side of the support portion 13 of the cylinder body 2 of the connecting body 17, and a second link member 19 whose one end is rotatably connected to a second mounting portion 17b that protrudes from the support portion 13 side of the cylinder body 2 of the connecting body 17. The other end of the first link member 18 is rotatably connected to the rear end of the clamp arm 15, and the other end of the second link member 19 is rotatably connected to a connecting member 14. Furthermore, the connection position of one end of the first link member 18 and one end of the second link member 19 is set to be at the same height as the connection position of the other end of the second link member 19 connected to the connecting member 14. In this embodiment, the support portion 13, clamp arm 15, connecting member 14, and link mechanism 16 are rotatably connected via a pin member.

[0011] The operation of the clamping device 1 equipped with the link mechanism 16 described above will now be explained. After the workpiece W is placed on the workpiece mounting section 20 of the jig, from the state shown in Figure 3, pressurized fluid is supplied from the other connection port 10b to the second cylinder chamber 6b, and the pressurized fluid in the first cylinder chamber 6a is discharged from the one connection port 10a. As a result, the upward movement of the piston 7 moves the piston rod 8 and the connecting body 17 of the link mechanism 16 upward, causing the connecting member 14 to swing via the second link member 19, and the clamp arm 15 to push upward via the first link member 18. As the supply and discharge of the pressurized fluid continues and the piston rod 8 moves to a predetermined position, the clamp arm 15 moves to the clamping position to clamp the workpiece W via the first link member 18 and the second link member 19, and clamps the workpiece W (Figure 1). When changing to the next workpiece W, from the state shown in Figure 1, pressurized fluid is supplied to the first cylinder chamber 6a from one connection port 10a, and the pressurized fluid in the second cylinder chamber 6b is discharged from the other connection port 10b. The piston 7 moves downward, moving the piston rod 8 and the connecting body 17 of the link mechanism 16 downward, and the clamp arm 15 is moved to an unclamped position below the clamping surface of the workpiece W by the first link member 18 and the second link member 19 (Figure 3). After that, the workpiece W is inserted and removed from above the clamping device 1.

[0012] From the above, the link mechanism 16 allows the piston rod 8 to move one of the second link members 19 between the piston rod 8 and the support part 13 via the connecting body 17, thereby increasing the amount of oscillation of the connecting member 14 relative to the travel distance L of one of the second link members 19. Even if the travel distance L of one of the second link members 19 is reduced compared to the conventional design, the oscillation of the connecting member 14 allows the clamp arm 15 to move between the clamp position and the unclamped position. Therefore, the travel distance L of the piston rod 8 can be shortened and the cylinder body 2 can be made smaller. The thickness T of the jig base 30 can be reduced, resulting in a lighter overall jig, and the height P1 of the clamp surface corresponding to the travel distance L of the piston rod 8 can be lowered, allowing for a smaller clamping device 1. In this embodiment, the connection positions of one of the first link members 18 and one and the other of the second link member 19 are at the same height. However, as shown in Figure 7, the travel distance L1 of one of the second link members 19 can be further shortened by lowering the connection position of one of the second link members 19. Furthermore, the height P2 of the clamping surface corresponding to the travel distance L1 of the piston rod 8 also decreases. [Explanation of symbols]

[0013] 1. Clamping device 2 Cylinder body 7 pistons 8 Piston rods 13 Support part 14 Connecting members 15 Clamp Arm 16 Link mechanism 17 Connecting body 17a First mounting portion 17b Second mounting portion 18 First link member 19 Second link member

Claims

[Claim 1] A clamping device is characterized in that a piston housed in a cylinder body is reciprocated by pressurized fluid supplied from a pair of pipe ports provided in the cylinder body, a piston rod is connected to the piston, one end of a connecting member is rotatably connected to a support portion provided in the cylinder body, and a clamp arm, which is rotatably connected to the other end of the connecting member, is moved between a clamp position in contact with the clamping surface of a workpiece and an unclamping position located below the clamping surface of the workpiece by a link mechanism attached to the reciprocating piston rod, wherein the link mechanism consists of a connecting body attached to the piston rod, a first link member with one end rotatably connected to a first mounting portion protruding from the opposite side of the support portion of the cylinder body of the connecting body, and a second link member with one end rotatably connected to a second mounting portion protruding from the support portion side of the cylinder body of the connecting body, the other end of the first link member is rotatably connected to the rear end of the clamp arm, and the other end of the second link member is rotatably connected to the connecting member, and the piston rod moves one end of the second link member between the piston rod and the support portion via the connecting body.

Images