Clamping device

Abstract

The present invention provides a clamping device that allows for easy and instantaneous visual determination of whether or not a clamping force is being applied, even when the handle or clamping bolt is in a position close to clamping the clamped member. [Solution] The clamping device comprises a clamp arm mounted on a mounting member so as to be reciprocable, a pressing force application mechanism for applying pressing force to the clamp arm, and a clamp bolt for clamping the member to be clamped between the support member and the clamping member. The clamp arm has a screw cylinder having a male threaded portion on the outside and female threaded portions on the upper and lower parts on the inside, with the clamp bolt screwed into the female threaded portion of the screw cylinder, and the clamping device is equipped with a visible, protruding confirmation pin above the clamp bolt when the member to be clamped is clamped between the support member and the clamping member by this clamp bolt.

Description

[Technical Field] The present invention relates to a clamping device that is mounted on the upper surface of a table supporting a workpiece in an assembly line or welding operation for various products, and is used to clamp a workpiece in a predetermined position. [Background technology] A conventional toggle clamp is shown in Japanese Utility Model Publication No. 63-136838. The clamp bolt of the toggle clamp described in that publication comprises a base bracket, a workpiece pressing arm, and a handle, and the workpiece pressing arm and the handle are configured to be interlocked via a toggle mechanism. The workpiece pressing arm is formed of a pair of strip-shaped arm plates that sandwich the vertical pin receiving portion of the base bracket, and each arm plate is provided with a slit that extends longitudinally parallel to its lower edge. The ends of a plate-shaped nut are slidably fitted into both slits, and the plate-shaped nut is provided with a step that prevents rotation and engages with the edge of the slit. Furthermore, an adjustment bolt is passed through the central hole of a U-shaped washer fitted to the lower edge of the arm plate and screwed into the plate-shaped nut, and a lock nut on the adjustment bolt is tightened to the washer. In the clamping bolt section of this toggle clamp, the clamping position can be adjusted by moving a plate-shaped nut along the slit. However, after adjusting the height of the adjustment bolt and fixing it with the lock nut, it was difficult to visually determine the clamped or unclamped state when the adjustment bolt was close to the clamped position. In other words, there were instances where workers mistakenly assumed the workpiece was clamped, leading to processing or inspection, resulting in defective products or incorrect data. This also resulted in wasted effort to manually check the workpiece again before processing or inspection, or working under uncertain conditions. Furthermore, the misconception that the workpiece was clamped could lead to the creation of defective products or even accidents. The present invention eliminates the problems existing in the above-mentioned conventional technologies, and can easily and instantaneously judge by visual inspection whether a pressing force is applied or not even when the handle or the clamp bolt is in a position close to the state of clamping the clamped member. The object is to provide a clamping device. Means for Solving the Problem In order to solve the above problems, the clamping device of the present invention includes a support member for supporting a clamped member at a predetermined position, a mounting member mounted on the support member, and a clamping arm mounted on the mounting member so as to be reciprocally movable. A pressing force applying mechanism provided between the mounting member and the clamping arm for applying a pressing force to the clamping arm, and a clamping bolt provided on the clamping arm for clamping the clamped member between the support member. And, with respect to the clamping arm, it has an external male thread portion on the outside, and an upper female thread portion with a through hole through which a pin passes on the inside, and a counterbore shape at the lower part so that the pin does not come out. A clamping bolt, a compression spring is mounted between the stepped portion of the counterbore and the pin, and when the clamping surface side of the clamping bolt clamps the clamped member, the pin stored in the clamping bolt moves upward and protrudes from the hole of the upper retaining screw screwed into the clamping bolt, and a clamping device equipped with a clamping bolt that enables visual judgment of the clamping state by visually observing the protrusion of the pin of the clamping bolt. According to the clamping device in another embodiment of the present invention, the clamping bolt is provided so as to be position-adjustable along the clamping arm, and in the state where the clamped member is clamped between the support member by the clamping bolt, a cushioning material such as a clamping pad, a swing-type clamping pad, or a rubber-equipped clamping pad attached to the tip of the counterbore inside the clamping bolt on the clamped side is attached to also serve as an anti-loosening function. As an optimal clamping bolt for various usage purposes, there is also an effect of increasing the types as a clamping confirmation possible clamping bolt. In particular, although the swing pad sometimes turned over, by passing the confirmation pin, the movement of the pad was restricted and it no longer turned over. Furthermore, attaching a contact sensor and LED to the upper part of the clamp bolt's inspection side to improve visibility even in dark places, and emitting ON / OFF radio waves, would further enhance automation. [Brief explanation of the drawing] [Figure 1] Figure 1 shows the clamping and unclamping states of the toggle clamp of this invention. [Figure 2] Figure 2 shows the clamped and unclamped states of the clamp bolt. [Figure 3] Figure 3 shows the clamp bolt with the oscillating pad attached. [Figure 4-1] Figure 3 shows the toggle clamp with the clamp bolt in the ON position. [Figure 4-2] Figure 3 shows the clamp bolt of the toggle clamp in the OFF position. [Figure 5] Clamp bolt with oscillating clamp pad attached [Modes for carrying out the invention] Hereinafter, an embodiment of the toggle clamp embodying the present invention will be described with reference to Figures 1 to 3. As shown in Figure 1, a pair of fixed mounting plates 12, which serve as mounting members, are positioned on the upper surface of the base bracket 11, which serves as a support member. Each mounting plate 12 is fixed in place by four bolts 13 inserted through the base bracket 11 from below to above, and nuts 14 screwed onto them. A toggle mechanism 15, which serves as a pressing force application mechanism, is attached to the upper ends of both mounting plates 12. The clamp arm 17 extends almost horizontally, and its base end is rotatably connected between the upper ends of the two mounting plates 12 by a connecting pin 16. Therefore, the tip of the clamp arm 17 can reciprocate and rotate in the vertical direction. A pair of operating levers 19 extend almost vertically, and their lower ends are connected to the outer surface of the upper end of the mounting plate 12 by connecting pins 18 so as to be able to reciprocate and rotate in the front-rear direction. A toggle link 21 is positioned between the middle part of the clamp arm 17 and the middle part of the operating levers 19, and the toggle link 21 is connected to the clamp arm 17 and the operating levers 19, respectively, by connecting pins 22A and 22B. As shown in Figure 2, the clamp arm 17 is formed in a bifurcated shape by a pair of left and right arm pieces 23. A guide groove 24 is formed between the two arm pieces 23, passing vertically through them. A clamp bolt unit 25 is attached to the clamp arm 17 using these arm pieces 23 and the guide groove 24. This clamp bolt unit 25 is equipped with a threaded cylinder 26 that passes vertically through the guide groove 24. A first lock nut 27 and a second lock nut 28 are screwed onto the male threaded portion 26a formed on the outer circumference of this threaded cylinder 26. An upper washer 29 is interposed between the upper surface of the arm piece 23 and the lower surface of the first lock nut 27. A lower washer 30 is interposed between the lower surface of the arm piece 23 and the upper surface of the second lock nut 28. As shown in Figure 3, rotation restricting ribs 29a and 30a are bent and formed on both the left and right sides of the upper washer 29 and the lower washer 30, respectively, to engage with the upper and lower edges of the arm piece 23 and restrict the rotation of the upper washer 29 and the lower washer 30. The screw cylinder 26 has a hole in its center that penetrates it vertically, with female threaded portions 26a and 26b formed above and below it. When unclamped, the smaller diameter portion of the pin is housed in the female threaded portion 26a. When clamped, the tip of the pin is pushed, pushing back the compression spring that is pushing in the clamping direction on the upper side of the thicker portion of the pin, and the upper part of the pin protrudes from the clamping bolt, allowing the clamped state to be confirmed. In this embodiment, a means is provided that allows the operator to visually confirm that the pin inside the clamp bolt, which is fixed in the guide groove 24 of the clamp arm 17, is in a clamped state using a compression spring. Next, we will explain the operation of the toggle clamp configured as described above. As shown by the solid line in Figure 1, when the operating lever 19 of the toggle mechanism 15 is rotated clockwise around the connecting pin 18, the toggle mechanism 15 is held in a deactivated state. In this state, the workpiece W is placed in a predetermined position on the upper surface of the base bracket 11. To align with the position of the workpiece W, the clamp bolt unit 25 is moved horizontally along the guide groove 24 with the first lock nut 27 loosened, and the clamp position is adjusted. Then, the first lock nut 27 is rotated in the tightening direction to fix the screw cylinder 26 in the predetermined position on the clamp arm 17. In this state, the screw cylinder 26 is rotated to roughly adjust the height of the clamp bolt 31, bringing the pad 32 at the lower end of the clamp bolt 31 into contact with the upper surface of the workpiece W. In this state, the operating lever 19 of the toggle mechanism 15 is rotated counterclockwise around the connecting pin 18, pressing the clamp bolt 31 and pad 32 toward the upper surface of the workpiece W. This operation causes the connecting pin 22A to slightly exceed the dead line L connecting the center of the connecting pin 18 and the center of the connecting pin 22B, and is positioned to the right of it, so that the workpiece W is held in a clamped state with a predetermined pressing force. However, after rotating the toggle mechanism 15, it was not possible to confirm the clamping by visual inspection before machining and inspection. The toggle clamp of the above embodiment provides the following advantages: When the workpiece W is actually clamped, the confirmation pin protrudes from the head of the clamp bolt 31, allowing for confirmation and eliminating processing and inspection failures, while also improving work efficiency. By providing a hole in the center of the pivoting clamp component through which the thin part of the confirmation pin passes, at the tip of the clamp bolt that contacts the clamped material, the clamping force on the clamped material due to reliable surface contact can be increased. In this case, when the pivoting pad tilts to conform to the mating surface, the apparent diameter of the hole will decrease by the amount of the tilt, so it is even better to make it larger in anticipation of this, so that the confirmation pin and the hole in the pivoting pad do not interfere with each other. Furthermore, the pressing force application mechanism may be configured using a cam mechanism in addition to a toggle mechanism. Instead of the base bracket 11, the workpiece support table of the machine tool may be used as a support member. The clamping device may be used as a clamping jig for assembly lines of various products or for welding operations.

Claims

1. A clamping device comprising a support member for supporting a clamped member in a predetermined position, a mounting member attached to the support member, a clamp arm mounted to the mounting member so as to be reciprocally movable, a pressing force application mechanism provided between the mounting member and the clamp arm for applying pressing force to the clamp arm, and a clamp bolt provided on the clamp arm for clamping the clamped member between itself and the support member, wherein the clamp arm has a hole that penetrates vertically through a screw cylinder having an external female thread portion and internal female thread portions at the top and bottom, and further A stepped section is provided in the hole, into which a confirmation pin with a narrow upper and lower section is inserted. A mechanism is provided that allows the confirmation pin to protrude using the confirmation pin, the stepped section inside the male screw, and a compression spring. A set screw is screwed into the upper part of the clamp above the confirmation pin so that the confirmation pin and compression spring do not come out, and the fine part above the confirmation pin passes through the hole of the set screw. When the clamp bolt clamps the material to be clamped, the tip of the confirmation bolt on the clamped side comes into contact with the material to be clamped, pushing back the compression spring inside the clamp bolt, causing the upper confirmation pin to protrude from inside the screw cylinder, and allowing the clamping state to be confirmed.

2. A clamping device according to claim 1, wherein a swing clamp is attached to a cylindrical member having a male screw portion, and the swing clamp has a through hole on the side that contacts the material to be clamped through which a confirmation pin can pass.

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