Clamping device

Abstract

The present invention provides a clamping device with a simple structure that can reliably insert a movable body into the mounting hole of the clamped member. [Solution] The clamping device 3 comprises a main body 4, a movable body 5 inserted into a movable body guide hole 4a of the main body 4, and a shaft 6 inserted into a shaft guide hole 5a of the movable body 5. The movable body 5 moves between a first position and a second position in which the movable body 5 is inserted into the mounting hole 1a of the clamped member 1 and the insertion is completed. The movable body 5 has a first lateral hole 5f in its side wall, into which an engaging member 7 is inserted. The shaft 6 moves between a release position and a clamp position. When the movable body 5 is in the first position and in an intermediate position between the first and second positions, the engaging member 7, which is pressed against the inner circumferential surface of the movable body guide hole 4a and partially protrudes from the inner circumferential surface of the shaft guide hole 5a, engages with an engaged portion 6c provided on the shaft 6, thereby preventing the shaft 6 from moving from the release position to the clamp position.

Description

Technical Field

[0001] This invention relates to a clamping device.

Background Art

[0002] Conventionally, there has been a clamping device for clamping a workpiece (object to be clamped) serving as a clamped member (for example, see Patent Document 1). FIGS. 8 to 10 show this clamping device 21. In this clamping device 21, to set it to the lowered unclamped state shown in FIG. 8, pressure oil is discharged from the lock chamber 22 and the clamp chamber 23, and pressure oil is supplied to the release chamber 24 and the unclamp chamber 25. Then, the advancing / retreating member 26 moves to the lower limit position, and the output member 27 moves to the upper limit position. At this time, the magnetic body 28 faces the lower magnetic sensor 29, and the fact that the advancing / retreating member 26 is at the lower limit position is detected by this magnetic sensor 29.

[0003] To switch from the lowered unclamped state shown in FIG. 8 to the raised unclamped state shown in FIG. 9, pressure oil is discharged from the release chamber 24 and the unclamp chamber 25. Then, the advancing spring 30 raises the advancing / retreating member 26, and the support cylinder 31 provided above the advancing / retreating member 26 is inserted into the hole 20a of the workpiece 20. At this time, the magnetic body 28 faces the upper magnetic sensor 32, and the fact that the advancing / retreating member 26 has moved to the upper limit position is detected by this magnetic sensor 32.

[0004] And to switch from the raised unclamped state shown in FIG. 9 to the raised clamped state shown in FIG. 10, pressure oil is supplied to the lock chamber 22 and the clamp chamber 23. Then, the advancing / retreating member 26 is supported at the upper limit position, and the output member 27 descends. Due to the descent of this output member 27, the pressing portion 27b of the output rod 27a (output member 27) moves the engaging member 33 outward via the receiving surface 33a, and the outer peripheral surface of the engaging member 33 presses the inner peripheral surface of the hole 20a of the workpiece 20, whereby the workpiece 20 is clamped.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Japanese Patent Publication No. 2017-154246 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] However, in the conventional clamping device described above, if pressurized oil is supplied to the locking chamber 22 and clamping chamber 23 before switching from the lowered unclamping state shown in Figure 8 to the raised unclamping state shown in Figure 9, the outwardly moved engaging member 33 may interfere with the periphery of the hole 20a in the workpiece 20, and the support cylinder 31 may not be able to fully enter the hole 20a. For this reason, in this clamping device 21, it was necessary to provide a magnetic sensor 32 and a magnetic body 28 to detect when the reciprocating member 26 has moved to the upper limit position, and then supply pressurized oil to the locking chamber 22 and clamping chamber 23 to avoid this problem.

[0007] This invention was made to solve the aforementioned drawbacks of the conventional methods, and its objective is to provide a clamping device with a simple structure that can reliably insert a movable body into a mounting hole of a clamped member. [Means for solving the problem]

[0008] To achieve the above objective, the clamping device according to this invention has the following configuration: The clamping device according to claim 1 is a clamping device for clamping a member to be clamped having a mounting hole, comprising a main body, a movable body inserted into a movable body guide hole provided in the main body, a shaft inserted into a shaft guide hole provided in the movable body, an engaging member, and a pressing member. The movable body guide hole has a first movable body guide hole and a second movable body guide hole extending along a predetermined axial direction. The movable body has a first cylindrical portion inserted into the first movable body guide hole and a second cylindrical portion inserted into the second movable body guide hole, and is movable in the axial direction relative to the main body, and by moving, the movable body moves between a first position in which the second cylindrical portion is set back from the mounting hole and a second position in which the second cylindrical portion is inserted into the mounting hole and insertion is completed. The shaft guide hole has a first shaft guide hole located inside the first cylindrical portion and extending along the axial direction, and a second shaft guide hole located inside the second cylindrical portion and extending along the axial direction. The shaft has a first shaft portion inserted into the first shaft guide hole and a second shaft portion inserted into the second shaft guide hole, and is movable in the axial direction relative to the movable body, and the shaft moves between a release position and a clamp position as a result of this movement. The first cylindrical portion also has a first transverse hole penetrating its side wall, into which the engaging member is inserted. The second cylindrical portion also has a second transverse hole penetrating its side wall, into which the pressing member is inserted.

[0009] Therefore, when the movable body is in the first position and when it is in an intermediate position between the first and second positions, the engaging member, which is pressed against the inner circumferential surface of the first movable body guide hole and has a portion protruding from the inner circumferential surface of the first shaft guide hole, engages with the engaged portion provided on the first shaft, thereby preventing the shaft from moving from the release position to the clamp position, and the shaft is held in the release position.

[0010] Furthermore, when the shaft is in the release position, the pressing member is allowed to move inward toward the second cylindrical portion, and the second cylindrical portion is able to move in and out of the mounting hole.

[0011] When the movable body is in the second position and the shaft is in the clamp position, the pressing member is pressed against the second shaft portion and presses against the inner circumferential surface of the mounting hole, thereby preventing the second cylindrical portion from coming out of the mounting hole.

[0012] With this clamping device, when the movable body is in the first position, the second cylindrical portion of the movable body is positioned away from the mounting hole of the clamped member. Therefore, by moving the clamped member laterally perpendicular to the axial direction relative to the clamping device, the mounting hole can be positioned opposite the second cylindrical portion. Then, by moving the movable body from the first position to the second position together with the shaft, the second cylindrical portion fully enters the mounting hole. During this time, the shaft is in the release position, and the second cylindrical portion can move in and out of the mounting hole. Subsequently, when the shaft is moved from the release position to the clamp position, the pressing member pushed by the second shaft portion of the shaft presses against the inner surface of the mounting hole, preventing the second cylindrical portion, and thus the movable body, from coming out of the mounting hole, and clamping the clamped member. Conversely, to release the clamp, the shaft is moved from the clamp position to the release position. Then, by moving the movable body from the second position to the first position together with the shaft, the second cylindrical portion exits the mounting hole.

[0013] Here, an engaging member is inserted into a first lateral hole provided in the circumferential wall of the first cylindrical portion of the movable body, and an engaged portion is provided on the first axial portion of the shaft. When the movable body is in the first position and when it is in an intermediate position between the first and second positions, the engaging member is pressed against the inner circumferential surface of the first movable body guide hole, causing a portion of it to protrude from the inner circumferential surface of the first shaft guide hole of the movable body and engage with the engaged portion of the first axial portion, and the shaft is held in the released position.

[0014] Furthermore, the clamping device according to claim 2 is the clamping device according to claim 1, wherein when the movable body is in the second position and the shaft is in the release position, a part of the engaging member can enter a recess provided on the inner circumferential surface of the first movable body guide hole, and by entering, the engagement between the engaged portion and the engaging member of the shaft is released, and the shaft becomes movable between the release position and the clamping position, and when the shaft is in the clamping position, the engaging member, which is pushed by the outer circumferential surface of the first shaft portion and protrudes a part from the outer circumferential surface of the first cylindrical portion, engages with the recess, preventing the movable body from moving from the second position to the first position, and the movable body is held in the second position. Therefore, when the movable body moves from the first position to the second position together with the shaft while the shaft remains in the released position, a part of the engaging member becomes able to enter a recess provided on the inner circumferential surface of the first movable body guide hole. This entry releases the engagement between the engaged portion and the engaging member, allowing the shaft to move from the released position to the clamped position.

[0015] Furthermore, the clamping device according to claim 3 is the clamping device according to claim 1 or 2, wherein the movement of the shaft and the movable body is performed by the pressure of the fluid entering and leaving the main body and the movable body.

[0016] Furthermore, the clamping device according to claim 4 is the clamping device according to claim 3, further comprising an elastic member that biases the shaft toward the clamping position from the release position to the clamping position relative to the movable body. As a result, even if the fluid pressure drops due to a power outage or the like, the shaft in the clamping position can be held in that position by the elastic member, thereby maintaining the clamped state of the member to be clamped.

[0017] Furthermore, the clamping device according to claim 5 is the clamping device according to claim 1 or 2, wherein the second shaft portion has a recess on its circumferential surface and an action surface located on the side of the shaft toward the release position from the clamping position relative to the recess, which is further away from the axis of the second shaft portion than the recess and is inclined to move further away from the axis as it moves away from the recess. Therefore, when the shaft is in the release position, the recess of the second shaft portion is positioned opposite the pressing member, and the pressing member is allowed to move toward the inside of the second cylindrical portion. When the shaft is in the clamping position, the action surface of the second shaft portion is positioned opposite the pressing member, and the pressing member is pressed by the action surface and presses against the inner circumferential surface of the mounting hole.

[0018] Furthermore, the clamping device according to claim 6 is the clamping device according to claim 1 or 2, wherein the main body is provided with a fixing portion to which a receiving member that receives the clamped member in the axial direction is attached and fixed. [Effects of the Invention]

[0019] According to the clamping device of this invention, with a simple structure consisting of an engaging member and an engaged part, the shaft can be held in the released position while the movable body moves from the first position to the second position. As a result, the movable body can be reliably inserted into the mounting hole of the clamped member without the pressing member interfering with the periphery of the mounting hole of the clamped member. [Brief explanation of the drawing]

[0020] [Figure 1] This is a cross-sectional view of a clamping device according to one embodiment of the present invention, where the movable body is in the first position and the shaft is in the release position. [Figure 2] This is also a perspective view of the clamping device. [Figure 3] Similarly, this is a disassembled perspective view of the clamping device. [Figure 4]Also, it is a cross-sectional view showing the installation state of the clamping device when the movable body is in the first position and the shaft is in the release position. [Figure 5] Also, it is a cross-sectional view showing the movable body between the first position and the second position and the shaft in the release position. [Figure 6] Also, it is a cross-sectional view showing the movable body in the second position and the shaft in the release position. [Figure 7] Also, it is a cross-sectional view showing the movable body in the second position and the shaft in the clamping position. [Figure 8] It is a cross-sectional view showing the lowering unclamping state of the conventional clamping device. [Figure 9] Also, it is a cross-sectional view showing the raising unclamping state. [Figure 10] Also, it is a cross-sectional view showing the raising clamping state.

Embodiments for Carrying Out the Invention

[0021] Hereinafter, embodiments for carrying out this invention will be described based on the drawings.

[0022] Figs. 1 to 7 show an embodiment of the present invention. Reference numeral 1 in the figures indicates a clamped member, and this clamped member 1 has a mounting hole 1a. 2 indicates a receiving member. 3 indicates a clamping device for clamping the clamped member 1.

[0023] The clamping device 3 comprises a main body 4, a movable body 5 inserted into a movable body guide hole 4a provided in the main body 4, a shaft 6 inserted into a shaft guide hole 5a provided in the movable body 5, an engaging member 7, and a pressing member 8. Here, the movable body guide hole 4a provided in the main body 4 has a first movable body guide hole 4b and a second movable body guide hole 4c that extend along a predetermined axial direction 3a. Therefore, the movable body 5 has a first cylindrical portion 5b that is inserted into the first movable body guide hole 4b of the main body 4, and a second cylindrical portion 5c that is inserted into the second movable body guide hole 4c of the main body 4, and is movable in the axial direction 3a relative to the main body 4, and as a result of this movement, the movable body 5 moves between a first position (see Figures 1 and 4) in which the second cylindrical portion 5c is set back from the mounting hole 1a of the clamped member 1, and a second position (see Figures 6 and 7) in which the second cylindrical portion 5c is inserted into the mounting hole 1a of the clamped member 1 and the insertion is completed. At this time, in the first position, the movable body 5 is stored inside the movable body guide hole 4a (inside the main body 4), and in the second position, the tip of the second cylindrical portion 5c protrudes from the movable body guide hole 4a (main body 4).

[0024] The shaft guide hole 5a provided in the movable body 5 has a first shaft guide hole 5d located inside the first cylindrical portion 5b and extending along the axial direction 3a, and a second shaft guide hole 5e located inside the second cylindrical portion 5c and extending along the axial direction 3a. The shaft 6 has a first shaft portion 6a inserted into the first shaft guide hole 5d of the movable body 5, and a second shaft portion 6b inserted into the second shaft guide hole 5e of the movable body 5. The shaft 6 is movable in the axial direction 3a relative to the movable body 5, and as a result of this movement, the shaft 6 moves between a release position (see Figures 1, 4 to 6) and a clamp position (see Figure 7) (more specifically, between the release position and the clamp position, which is located on the side of the movable body 5 that is moving from the first position toward the second position than the release position).

[0025] Furthermore, the first cylindrical portion 5b of the movable body 5 has a first transverse hole 5f that penetrates its side wall, and the engaging member 7 is inserted into the first transverse hole 5f. Similarly, the second cylindrical portion 5c of the movable body 5 has a second transverse hole 5g that penetrates its side wall, and the pressing member 8 is inserted into the second transverse hole 5g.

[0026] Therefore, when the movable body 5 is in the first position (see Figure 4) and when it is in an intermediate position between the first and second positions (see Figure 5), the engaging member 7, which is pressed against the inner surface of the first movable body guide hole 4b of the main body 4 and protrudes in part from the inner surface of the first shaft guide hole 5d of the movable body 5, engages with the engaged portion 6c provided on the first shaft portion 6a of the shaft 6, thereby preventing the shaft 6 from moving from the release position to the clamp position, and the shaft 6 is held in the release position. When the movable body 5 is in the second position and the shaft 6 is in the release position (see Figure 6), a part of the engaging member 7 becomes able to enter the recess 4d provided on the inner surface of the first movable body guide hole 4b of the main body 4, and by entering, the engagement between the engaged portion 6c and the engaging member 7 of the shaft 6 is released, and the shaft 6 becomes able to move between the release position (see Figure 6) and the clamp position (see Figure 7). When the shaft 6 is in the clamp position ( More specifically, when the movable body 5 is in an intermediate position between the release position and the clamp position, and when it is in the clamp position, the engaging member 7, which is pressed against the outer circumferential surface of the first shaft portion 6a and partially protrudes from the outer circumferential surface of the first cylindrical portion 5b, engages with the recess 4d, thereby preventing the movable body 5 from moving from the second position to the first position, and the movable body 5 is held in the second position. In the illustrated embodiment, there is some play in the engagement between the engaging member 7 and the recess 4d, and therefore the position that becomes the second position has a slight range.

[0027] Here, when the shaft 6 is in the release position (see Figures 4 to 6), the pressing member 8 is allowed to move inward toward the second cylindrical portion 5c of the movable body 5, and the second cylindrical portion 5c is able to move in and out of the mounting hole 1a of the clamped member 1. Then, when the movable body 5 is in the second position and the shaft 6 is in the clamp position (see Figure 7), the pressing member 8 is pushed by the second axial portion 6b of the shaft 6 and presses against the inner circumferential surface of the mounting hole 1a of the clamped member 1, thereby preventing the second cylindrical portion 5c from coming out of the mounting hole 1a.

[0028] In detail, the second shaft portion 6b of the shaft 6 has a recess 6d on its circumferential surface, and an action surface 6e that is located on the side of the shaft 6 from the clamp position toward the release position relative to the recess 6d, further away from the axis of the second shaft portion 6b than the recess 6d, and is inclined so that it moves further away from the axis of the second shaft portion 6b as it moves away from the recess 6d. Therefore, when the shaft 6 is in the release position (see Figures 4 to 6), the recess 6d of the second shaft portion 6b is positioned opposite the pressing member 8 inserted into the second lateral hole 5g of the second cylindrical portion 5c (movable body 5), allowing the pressing member 8 to move inward toward the second cylindrical portion 5c. Then, when the shaft 6 is in the clamp position (see Figure 7), the action surface 6e of the second shaft portion 6b is positioned opposite the pressing member 8, and the pressing member 8 is pressed by the action surface 6e and presses against the inner circumferential surface of the mounting hole 1a of the clamped member 1.

[0029] Furthermore, in the clamping device 3, the movement of the shaft 6 and the movable body 5 is carried out by the pressure of a fluid such as air entering and exiting the main body 4 and the movable body 5 (specifically, the first movable body guide hole 4b and the first shaft guide hole 5d). The clamping device 3 is also equipped with an elastic member 9 that biases the shaft 6 relative to the movable body 5 in the direction from the release position toward the clamping position.

[0030] Furthermore, the receiving member 2 receives the clamped member 1 in the axial direction 3a, and the main body 4 of the clamping device 3 is provided with a fixing part 4e to which the receiving member 2 is attached and fixed.

[0031] Specifically, the clamped member 1 has a tapered surface 1b on the inner circumferential surface of the mounting hole 1a, in which the diameter increases towards the inner side where the second cylindrical portion 5c of the movable body 5 is inserted (in other words, the diameter decreases towards the receiving member 2 side). When the movable body 5 is in the second position and the shaft 6 is in the clamping position (see Figure 7), the pressing member 8 presses against this tapered surface 1b. More specifically, the clamped member 1 comprises a clamped member body 101 having an auxiliary hole 1c, and a cylindrical mounting auxiliary member 102 that is attached and fixed to the auxiliary hole 1c and whose inner side is the mounting hole 1a. More specifically, the mounting auxiliary member 102 is attached to the auxiliary hole 1c (clamped member body 101) using a nut 1d.

[0032] The receiving member 2 is formed, for example, in the shape of a plate, and receives the clamped member 1. This receiving member 2 has a through hole 2a, and the second cylindrical portion 5c of the movable body 5 is inserted into the mounting hole 1a through this through hole 2a.

[0033] In the illustrated embodiment, the clamping device 3 is positioned such that the axial direction 3a is vertical, the first position of the movable body 5 (and furthermore, the release position of the shaft 6) is on the lower side, and the second position of the movable body 5 (and furthermore, the clamping position of the shaft 6) is on the upper side. A receiving member 2 is attached and fixed to the fixing portion 4e of the upper end of the clamping device 3 (more specifically, the main body 4) using a bolt 10 as a fastener, and the clamped member 1 is positioned so as to rest on the receiving member 2.

[0034] In this clamping device 3, the main body 4 is formed in a cylindrical shape along the axial direction 3a. The main body 4 comprises a bottomed cylindrical main body member 401 and a lid member 402 that covers the opening side (upper side in the illustrated embodiment) of the main body member 401. The lid member 402 is fixed to the main body member 401 by bolts 11 as fasteners. The lid member 402 has a projection 4f protruding from the center of its upper surface, and this projection 4f is inserted into the through hole 2a of the receiving member 2. Here, the inside of the main body member 401 becomes the first movable body guide hole 4b, and a hole drilled vertically through the center of the lid member 402 becomes the second movable body guide hole 4c, which is formed to have a smaller diameter than the first movable body guide hole 4b. The recess 4d is formed in a groove shape on the inner circumferential surface of the first movable body guide hole 4b. Furthermore, the peripheral wall of the main body 4 (more specifically, the peripheral wall of the main body member 401) is provided with a first supply / discharge port 4g and a second supply / discharge port 4h for supplying and discharging fluids such as air, which are accessible from the outside to the first movable body guide hole 4b, with the first supply / discharge port 4g located on the lower side and the second supply / discharge port 4h located on the upper side.

[0035] The movable body 5 is composed of the aforementioned first cylindrical portion 5b and second cylindrical portion 5c, with the first cylindrical portion 5b on the lower side and the second cylindrical portion 5c on the upper side. The second cylindrical portion 5c is formed to have a smaller diameter than the first cylindrical portion 5b, and the second shaft guide hole 5e is formed to have a smaller diameter than the first shaft guide hole 5d. In detail, a groove is provided at the tip (lower end) of the inner circumferential surface of the first shaft guide hole 5d, and a retaining ring 12 is fitted into this groove. A washer 13 is provided between the retaining ring 12 and the shaft 6 (more specifically, the first shaft portion 6a) inside the first shaft guide hole 5d, and the washer 13 is prevented from coming off by the retaining ring 12, and furthermore, the washer 13 prevents the first shaft portion 6a, and thus the shaft 6, from coming off. In other words, the washer 13 and retaining ring 12 prevent the shaft 6 from moving from the release position to the opposite side of the clamp position. In the second shaft guide hole 5e, the side closer to the first shaft guide hole 5d becomes the base end guide hole 5h, and the side further away from the first shaft guide hole 5d becomes the tip end guide hole 5i, with the tip end guide hole 5i being slightly smaller in diameter than the base end guide hole 5h. The aforementioned second lateral hole 5g is provided on the side with the tip end guide hole 5i.

[0036] When the movable body 5 is in the first position, the end face (lower surface) of the first cylindrical portion 5b abuts against the bottom wall 4i of the main body member 401 (main body 4). When it is in the second position, the step portion that transitions from the first cylindrical portion 5b to the second cylindrical portion 5c (i.e., the upper surface of the first cylindrical portion 5b) abuts against the lower surface of the lid member 402. However, as mentioned above, the position that constitutes the second position has a certain range, and the position just before the upper surface of the first cylindrical portion 5b abuts against the lower surface of the lid member 402 is also included in the second position.

[0037] Furthermore, in the illustrated embodiment, the engaging member 7 inserted into the first transverse hole 5f is spherical, and in particular made of a steel ball. Similarly, the pressing member 8 inserted into the second transverse hole 5g is spherical, and in particular made of a steel ball.

[0038] The shaft 6 is composed of the aforementioned first shaft portion 6a and second shaft portion 6b, with the first shaft portion 6a on the lower side and the second shaft portion 6b on the upper side. The second shaft portion 6b is formed to have a smaller diameter than the first shaft portion 6a. The stepped portion where the shaft transitions from the first shaft portion 6a to the second shaft portion 6b (i.e., the upper surface of the first shaft portion 6a), or the corner portion between the stepped portion and the outer circumferential surface of the first shaft portion 6a (the corner portion in the illustrated embodiment), becomes the aforementioned engaged portion 6c. The first shaft portion 6a is provided with a vertical hole 6f in the center, and the coil spring 9a, which is the elastic member 9, is inserted into this vertical hole 6f. The coil spring 9a is then supported by the washer 13, and the coil spring 9a biases the shaft 6 in the direction from the release position to the clamp position. The second shaft portion 6b is formed such that the side closer to the first shaft portion 6a becomes the base end shaft portion 6g, and the side further away from the first shaft portion 6a becomes the tip end shaft portion 6h, with the tip end shaft portion 6h having a slightly smaller diameter than the base end shaft portion 6g. The base end shaft portion 6g is inserted into the base end guide hole 5h, and the tip end shaft portion 6h is inserted into the tip end guide hole 5i.

[0039] Incidentally, within the first movable body guide hole 4b of the main body 4, the space below the first cylindrical portion 5b (that is, the side in the direction in which the movable body 5 moves from the second position to the first position) becomes the first fluid chamber 4j, and the space above the first cylindrical portion 5b (that is, the side in the direction in which the movable body 5 moves from the first position to the second position) becomes the second fluid chamber 4k. In other words, the space below the first movable body guide hole 4b, which is divided by the first cylindrical portion 5b (more specifically, the packing 14 provided to make the space between the inner circumferential surface of the first movable body guide hole 4b and the outer circumferential surface of the first cylindrical portion 5b tightly sealed), is the first fluid chamber 4j, and the space above it is the second fluid chamber 4k. Here, the lower part of the first cylindrical portion 5b is formed with a slightly smaller diameter, and the space created by this smaller diameter is included in the first fluid chamber 4j. Furthermore, the first cylindrical portion 5b has an arc-shaped notch 5x at the lower end of its peripheral wall, and the space within the notch 5x is included in the first fluid chamber 4j. The upper part of the first cylindrical portion 5b is formed to be slightly smaller in diameter, and the space created by this smaller diameter is included in the second fluid chamber 4k. The aforementioned first supply and discharge port 4g is provided so as to lead from the outside to the first fluid chamber 4j, and the aforementioned second supply and discharge port 4h is provided so as to lead from the outside to the second fluid chamber 4k.

[0040] Furthermore, within the first shaft guide hole 5d of the movable body 5, the space below the first shaft portion 6a (i.e., the side in which the shaft 6 moves from the clamped position to the released position) becomes the third fluid chamber 5j, and the space above the first shaft portion 6a (i.e., the side in which the shaft 6 moves from the released position to the clamped position) becomes the fourth fluid chamber 5k. In other words, the space below the first shaft guide hole 5d, which is divided by the first shaft portion 6a (more specifically, the packing 15 provided to tightly seal the space between the inner circumferential surface of the first shaft guide hole 5d and the outer circumferential surface of the first shaft portion 6a), is the third fluid chamber 5j, and the space above it is the fourth fluid chamber 5k. Here, the third fluid chamber 5j exits downward and communicates with the first fluid chamber 4j. The fourth fluid chamber 5k is in communication with the second fluid chamber 4k via a communication hole 5m (see Figure 3) that penetrates the peripheral wall of the first cylindrical portion 5b.

[0041] Therefore, when the movable body 5 is in the first position and the shaft 6 is in the released position (see Figure 4), when fluid is supplied from the first inlet / outlet port 4g and discharged from the second inlet / outlet port 4h, fluid is supplied to the first fluid chamber 4j and the fluid is discharged from the second fluid chamber 4k, causing the movable body 5 to move to the second position together with the shaft 6 (see Figure 6). Subsequently, fluid is supplied to the third fluid chamber 5j and the fluid is discharged from the fourth fluid chamber 5k, causing the shaft 6 to move to the clamped position (see Figure 7). Conversely, when the movable body 5 is in the second position and the shaft 6 is in the clamped position (see Figure 7), when fluid is supplied from the second inlet / outlet port 4h and discharged from the first inlet / outlet port 4g, fluid is supplied to the fourth fluid chamber 5k and the fluid in the third fluid chamber 5j is discharged, causing the shaft 6 to move to the release position (see Figure 6). Subsequently, fluid is supplied to the second fluid chamber 4k and the fluid in the first fluid chamber 4j is discharged, causing the movable body 5 to move to the first position together with the shaft 6 (see Figure 4). In the figures, reference numeral 16 indicates a packing fitted to the outside of the lid member 402, and reference numeral 17 indicates a packing fitted to the inside of the lid member 402. Reference numeral 18 indicates a packing fitted to the second shaft portion 6b (see Figure 1).

[0042] Next, the operation and effects of the clamping device 3, which has the above configuration, will be explained. With this clamping device 3, when the movable body 5 is in the first position, the second cylindrical portion 5c of the movable body 5 is positioned away from the mounting hole 1a of the clamped member 1. Therefore, the clamped member 1 can be moved laterally relative to the clamping device 3, perpendicular to the axial direction 3a, so that the mounting hole 1a is positioned opposite the second cylindrical portion 5c (see Figure 4). Then, by moving the movable body 5 from the first position to the second position together with the shaft 6, the second cylindrical portion 5c is fully inserted into the mounting hole 1a (see Figure 6). During this time, the shaft 6 is in the released position, and the second cylindrical portion 5c is able to move in and out of the mounting hole 1a. Subsequently, when the shaft 6 is moved from the release position to the clamping position, the pressing member 8, which is pressed by the second shaft portion 6b of the shaft 6 (more specifically, the working surface 6e), presses against the inner circumferential surface of the mounting hole 1a (more specifically, the tapered surface 1b), preventing the second cylindrical portion 5c, and thus the movable body 5, from coming out of the mounting hole 1a, and the clamped member 1 is clamped (see Figure 7). Conversely, to release the clamp, the shaft 6 is moved from the clamping position to the release position (see Figure 6). Then, by moving the movable body 5 together with the shaft 6 from the second position to the first position, the second cylindrical portion 5c comes out of the mounting hole 1a (see Figure 4).

[0043] Here, an engaging member 7 is inserted into a first lateral hole 5f provided in the circumferential wall of the first cylindrical portion 5b of the movable body 5, and an engaged portion 6c is provided on the first shaft portion 6a of the shaft 6, and a recess 4d is provided on the inner circumferential surface of the first movable body guide hole 4b of the main body 4. When the movable body 5 is in the first position, the engaging member 7 is pressed against the inner circumferential surface of the first movable body guide hole 4b, and a portion of it protrudes from the inner circumferential surface of the first shaft guide hole 5d of the movable body 5, engaging with the engaged portion 6c of the first shaft portion 6a, and the shaft 6 is held in the released position (see Figure 4). As the movable body 5 moves from the first position to the second position together with the shaft 6 while the shaft 6 remains in the released position, a portion of the engaging member 7 becomes able to enter the recess 4d provided on the inner circumferential surface of the first movable body guide hole 4b. This entry releases the engagement between the engaged portion 6c and the engaging member 7, allowing the shaft 6 to move from the released position to the clamped position (see Figure 6).

[0044] In other words, with this clamping device 3, the shaft 6 can be held in the released position while the movable body 5 moves from the first position to the second position, with a simple structure consisting of an engaging member 7 and a engaged portion 6c. This allows the movable body 5 (specifically, the second cylindrical portion 5c) to be reliably inserted into the mounting hole 1a of the clamped member 1 without the pressing member 8 interfering with the periphery of the mounting hole 1a. When the movable body 5 moves to the second position, the engagement between the engaged portion 6c and the engaging member 7 is released by the entry of the engaging member 7 into the recess 4d, allowing the shaft 6 to move to the clamped position.

[0045] Furthermore, the clamping device 3 is equipped with an elastic member 9 (specifically, a coil spring 9a) that biases the shaft 6 relative to the movable body 5 in the direction from the release position toward the clamping position. As a result, even if the fluid pressure drops due to a power outage or the like, the shaft 6 in the clamping position can be held in that position by the elastic member 9, thereby maintaining the clamped state of the clamped member 1.

[0046] It should be noted that the present invention is not limited to the embodiments described above, and various other modifications are possible. For example, the fluid used to operate the clamping device 3 does not have to be a gas such as air, but may be a liquid such as oil. Furthermore, the clamping device 3 may be operated not only by a fluid, but also by moving the shaft 6 (and the movable body 5) manually or electrically.

[0047] Furthermore, an elastic member 9 is provided to bias the shaft 6 toward the clamping position from the release position, but this elastic member 9 is optional.

[0048] Furthermore, the engaging member 7 is not limited to a sphere, but can have any shape as long as it can engage with the engaged portion 6c of the first shaft portion 6a. Similarly, the pressing member 8 is not limited to a sphere, but can have any shape as long as it can press against the inner circumferential surface of the mounting hole 1a.

[0049] Furthermore, although the clamped member 1 is provided with a mounting auxiliary member 102, the clamped member body 101 may be directly provided with a mounting hole 1a without using this mounting auxiliary member 102. Also, although the inner circumferential surface of the mounting hole 1a has a tapered surface 1b and the pressing member 8 presses against this tapered surface 1b, the inner circumferential surface parallel to the axis of the mounting hole 1a may simply be pressed without providing a tapered surface 1b. [Explanation of Symbols]

[0050] 1. Clamped member 1a Mounting hole 2. Support member 3. Clamping device 3a Axial direction 4 Main unit 4a Movable body guide hole 4b 1st movable body guide hole 4c Second movable body guide hole 4d recess 4e Fixed part 5 Movable body 5a Shaft guide hole 5b First cylindrical part 5c Second cylindrical part 5d First shaft guide hole 5e Second shaft guide hole 5f 1st horizontal hole 5g 2nd horizontal hole 6 shafts 6a First shaft section 6b 2nd shaft part 6c Engaged part 6d indentation 6e Working surface 7 Engaging Member 8 Pressing member 9 Elastic members

Claims

1. A clamping device for clamping a clamped member having a mounting hole, The device comprises a main body, a movable body inserted into a movable body guide hole provided in the main body, a shaft inserted into a shaft guide hole provided in the movable body, an engaging member, and a pressing member. The movable body guide hole has a first movable body guide hole and a second movable body guide hole that extend along a predetermined axial direction. The movable body has a first cylindrical portion inserted into the first movable body guide hole and a second cylindrical portion inserted into the second movable body guide hole, and is movable in the axial direction relative to the main body, and by moving, the movable body moves between a first position in which the second cylindrical portion is set back from the mounting hole and a second position in which the second cylindrical portion is inserted into the mounting hole and insertion is completed. The shaft guide hole has a first shaft guide hole located inside the first cylindrical portion and extending along the axial direction, and a second shaft guide hole located inside the second cylindrical portion and extending along the axial direction. The shaft has a first shaft portion inserted into the first shaft guide hole and a second shaft portion inserted into the second shaft guide hole, and is movable in the axial direction relative to the movable body, and as a result of this movement, the shaft moves between a released position and a clamped position. The first cylindrical portion has a first transverse hole that penetrates its side wall, and the engaging member is inserted into the first transverse hole. The second cylindrical portion has a second transverse hole that penetrates its side wall, and the pressing member is inserted into the second transverse hole. When the movable body is in the first position and when it is in an intermediate position between the first and second positions, the engaging member, which is pressed against the inner circumferential surface of the first movable body guide hole and a portion of it protrudes from the inner circumferential surface of the first shaft guide hole, engages with the engaged portion provided on the first shaft, thereby preventing the shaft from moving from the released position to the clamped position, and the shaft is held in the released position. When the shaft is in the release position, the pressing member is allowed to move inward toward the second cylindrical portion, and the second cylindrical portion is able to move in and out of the mounting hole. A clamping device in which, when the movable body is in the second position and the shaft is in the clamping position, the pressing member is pressed against the second shaft portion and presses against the inner circumferential surface of the mounting hole, thereby preventing the second cylindrical portion from coming out of the mounting hole.

2. When the movable body is in the second position and the shaft is in the release position, a part of the engaging member becomes able to enter a recess provided on the inner circumferential surface of the first movable body guide hole, and by this entry, the shaft becomes able to move between the release position and the clamp position as the engagement between the engaged portion and the engaging member is released, and when the shaft is in the clamp position, the engaging member, which is pushed by the outer circumferential surface of the first shaft portion and protrudes a part from the outer circumferential surface of the first cylindrical portion, engages with the recess, thereby preventing the movable body from moving from the second position to the first position, and the movable body is held in the second position, as described in claim 1.

3. The clamping device according to claim 1 or 2, wherein the movement of the shaft and the movable body is performed by the pressure of fluid entering and leaving the main body and the movable body.

4. The clamping device according to claim 3, further comprising an elastic member that biases the shaft toward the clamping position from the release position to the clamping position relative to the movable body.

5. The second shaft portion has a recess on its circumferential surface, and an action surface located on the side of the shaft from the clamping position toward the release position relative to the recess, which is further from the axis of the second shaft portion than the recess, and which is inclined so that it moves further away from the axis as it moves away from the recess. When the shaft is in the release position, the recess of the second shaft portion faces the pressing member, and the pressing member is allowed to move inward toward the second cylindrical portion. The clamping device according to claim 1 or 2, wherein when the shaft is in the clamping position, the working surface of the second shaft portion is positioned opposite the pressing member, and the pressing member is pressed against the working surface to press against the inner circumferential surface of the mounting hole.

6. The clamping device according to claim 1 or 2, wherein the main body is provided with a fixing portion to which a receiving member that receives the clamped member in the axial direction is attached and fixed.

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