Clamping device

Abstract

To provide a clamp device that does not need pressure fluid such as compressed air for driving or needs just small amounts of pressure fluid even when needing the pressure fluid for driving, which can accurately position and fix an object to be clamped.SOLUTION: A clamp device comprises a main clamp (101) and a sub clamp (102). Output rods (4 and 30) are moved by operation members (7 and 32), through a cam rod (37), in a tip side direction of an axial direction, and also is moved by energizing means (9) in a base end direction of the axial direction. The main clamp (101) is configured to position an object to be clamped (WP) with a shaft center (C1) of the first output rod (4) as a reference. The sub clamp (102) is configured to position the object to be clamped (WP) in a direction crossing a linear line (CL).SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a clamping device suitable for detachably fixing an object to be clamped, such as a work pallet, a work piece, a mold, a tool, or a jig, to a clamping pallet as a base, a table, or the like.

Background Art

[0002] As such a clamping device, there is one described in Patent Document 1 below. The clamping device (clamp) according to the prior art is configured as follows.

[0003] The clamping device is composed of a cylindrical plug portion protruding from a housing, an output rod, an engaging ball, a piston, and the like. The housing constituting the clamping device is provided with a clamping chamber and an unclamping chamber to which pressure fluid is supplied and discharged. For driving the clamping device, that is, for driving the piston and the output rod, for example, compressed air is used, and each time it is driven, compressed air is supplied and discharged to the clamping chamber and the unclamping chamber.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When a large number of such clamping devices (clamps) are installed, as a compressed air supply facility, a large-scale facility is required. In addition, the piping facility for supplying and discharging compressed air becomes numerous and complex. These have aspects that are not preferable from the viewpoints of energy saving and environmental measures. Therefore, it is desirable that compressed air is not required as a drive source, or if it is required, it is minimized.

[0006] Furthermore, when improving the machining accuracy of machine parts, if the clamping device consists of only one clamp, it can be difficult to accurately position and secure the object to be clamped, such as a work pallet, using the clamping device.

[0007] The object of the present invention is to provide a clamping device that does not require a pressurized fluid such as compressed air for driving, or requires only a small amount of pressurized fluid for driving, and that can accurately position and fix an object to be clamped. [Means for solving the problem]

[0008] To achieve the above objective, the clamping device according to the present invention is configured as follows, for example, as shown in Figures 1 to 15.

[0009] (1) The clamping device disclosed herein comprises a main clamp 101 and a sub-clamp 102 fixed to a base CP at a predetermined interval, the main clamp 101 and the sub-clamp 102 for removably fixing an object to be clamped (WP). The main clamp 101 and the sub-clamp 102 each comprise a housing 1 fixed to the base CP, output rods 4 and 30 inserted into the housing 1 so as to be movable in the axial direction of the housing 1, a cylindrical hole 5 formed on the base end side of the housing 1 into which the output rods 4 and 30 are inserted so as to be movable in the axial direction, operating members 7 and 32 rotatably positioned on the base end face of the output rods 4 and 30, which push and move the output rods 4 and 30 in the tip direction in the axial direction, and biasing means 9 positioned inside or filled inside the cylindrical hole 5, which push and move the output rods 4 and 30 in the base direction in the axial direction. The main clamp 101 is configured to position the object to be clamped WP with reference to the axis C1 of the first output rod 4, which constitutes the output rod of the main clamp 101. The sub-clamp 102 is configured to position the object to be clamped WP in a direction intersecting a virtual straight line CL extending from the axis C1 to the axis C2 of the second output rod 30, which constitutes the output rod of the sub-clamp 102. The cam rod 37, which is positioned at a predetermined distance from the base CP, has a first cam groove 38 into which the first operating member 7, which constitutes the operating member of the main clamp 101, fits, and a second cam groove 39 into which the second operating member 32, which constitutes the operating member of the sub-clamp 102, fits, formed on its outer circumferential surface. The first cam groove 38 has a first cam surface 38a for pushing the first operating member 7 toward the tip, and the second cam groove 39 has a second cam surface 39a for pushing the second operating member 32 toward the tip. Prior to the second operating member 32 fitting into the second cam groove 39, the first operating member 7 fits into the first cam groove 38, thereby locking the object WP to be clamped by the main clamp 101 prior to the locking of the object WP to be clamped by the sub-clamp 102.The biasing means 9 is, for example, a spring or compressed gas (pressure gas).

[0010] Furthermore, prior to the second operating member 32 being moved toward the tip by the second cam surface 39a, the first operating member 7 may be moved toward the tip by the first cam surface 38a, so that the clamping object WP is locked by the main clamp 101 before the clamping object WP is locked by the sub-clamp 102.

[0011] The clamping device disclosed herein provides the following advantages. The clamping device does not have chambers, such as a clamping chamber and an unclamping chamber, which are supplied with and discharged pressurized fluid each time it is driven, as is the case with conventional clamping devices. In the clamping device, the output rod can be driven in the tip direction of the axial direction via an operating member by moving the cam rod manually or by an external force, or by moving the base manually or by an external force. In the other axial direction, the base direction, the output rod is driven by the biasing means. Therefore, the clamping device does not require pressurized fluid such as compressed air to be driven, or if pressurized fluid is required to be driven, only a small amount is needed.

[0012] Furthermore, the clamped object can be positioned and fixed with high precision by the main clamp, which is configured to position the clamped object relative to the axis of the first output rod, prior to the locking of the clamped object by the sub-clamp, which is configured to position the clamped object in a direction intersecting a virtual straight line extending from the axis of the first output rod to the axis of the second output rod.

[0013] (2) In the clamping device of (1), the main clamp 101 and the sub-clamp 102 may each have a cylindrical plug portion 3 protruding from the housing 1 and annular collets 17, 33 fitted onto the plug portion 3, the collets 17, 33 being elastically reduced in diameter. The outer circumferential surface 17a of the first collet 17 constituting the main clamp 101 is a tapered outer circumferential surface that is circular or polygonal in plan view, or a tapered outer circumferential surface having at least three protrusions 45 on its side surface at equal intervals from one another in the circumferential direction, and the outer circumferential surface 33a of the second collet 33 constituting the sub-clamp 102 may be a tapered outer circumferential surface having protrusions 36 on its side surface in a direction intersecting the straight line CL.

[0014] This configuration allows for precise positioning and fixing of the object to be clamped.

[0015] (3) In the clamping device of (1) or (2), a first recess 6 and a second recess 31 are formed on the base end face of the first output rod 4 and the base end face of the second output rod 30, respectively, and the first operating member 7 is rotatably housed in the first recess 6, and the second operating member 32 is rotatably housed in the second recess 31.

[0016] This configuration facilitates the arrangement of each operating member at the base end face of each output rod.

[0017] (4) In any of the clamping devices described in (1) to (3), the cam rod 37 may be movable along the base CP.

[0018] This configuration allows for easy and precise positioning and fixing of clamped objects using a clamping device that does not require compressed air or other pressurized fluids for operation, or requires only a small amount of pressurized fluid for operation.

[0019] (5) In any of the clamping devices (1) to (4), the first operating member 7 and the second operating member 32 may be a sphere or a roller.

[0020] According to this configuration, each output rod can be smoothly moved in the tip-side direction in the axial direction.

[0021] (6) In the clamping device (3), first holes 27 and second holes 34 are provided at the center of the bottom of the first recess 6 and the second recess respectively, and the clamping device may further include first magnets 28 and second magnets 35 respectively accommodated in the first holes 27 and the second holes 34. In this case, the first output rod 4, the second output rod 30, the first operating member 7, and the second operating member 32 are formed of a magnetic material attracted by the magnets.

[0022] According to this configuration, the magnets can prevent each operating member from falling due to gravity.

[0023] (7) In any of the clamping devices (1) to (6), the biasing means 9 may be a spring 9.

[0024] According to this configuration, a clamping device that does not require a pressure fluid such as compressed air for driving can be obtained.

[0025] (8) In any of the clamping devices (1) to (7), the main clamp 101 and the sub-clamp 102 each include a cylindrical plug portion 3 protruding from the housing 1 and an engaging member 14 inserted into a through hole 13 formed in the peripheral wall of the plug portion 3. When the output rods 4 and 30 are moved in the axial direction, they are moved within the through hole 13 and can abut against a locking portion 25 of a mounting hole 24 provided in the clamping object WP so that the plug portion 3 can be inserted.

[0026] According to this configuration, the clamping object can be firmly and accurately positioned and fixed.

Advantages of the Invention

[0027] According to the present invention, there is provided a clamping device that does not require a pressure fluid such as compressed air for driving, or requires only a small amount of pressure fluid for driving, and can accurately position and fix an object to be clamped.

Brief Description of the Drawings

[0028] [Figure 1] FIG. 1 shows a first embodiment of the present invention and is a partial cross-sectional view in side view of the clamping device in a released state. [Figure 2] FIG. 2 is a view taken along the arrow Y-Y of FIG. 1. [Figure 3] FIG. 3 is a view taken along the arrow X-X of FIG. 1. [Figure 4] FIG. 4 is an enlarged view of part A of FIG.  1. [Figure 5] FIG. 5 is an enlarged view of part C of FIG. 2. [Figure 6] FIG. 6 is a perspective view of the main clamp shown in FIG. 1. [Figure 7] FIG. 7 is an enlarged view of part B of FIG. 1. [Figure 8] FIG. 8 is an enlarged view of part D of FIG. 2. [Figure 9] FIG. 9 is a perspective view of the sub-clamp shown in FIG. 1. [Figure 10] FIG. 10 shows a first stage when the clamping device shown in FIG. 1 switches from the released state to the locked state and is a partial cross-sectional view in side view of the clamping device. [Figure 11] FIG. 11 shows a second stage when the clamping device shown in FIG. 1 switches from the released state to the locked state and is a partial cross-sectional view in side view of the clamping device. [Figure 12] FIG. 12 is a partial cross-sectional view in side view of the clamping device shown in FIG. 1 in the locked state. [Figure 13] FIG. 13 shows a second embodiment of the present invention and is a partial cross-sectional view in side view of the clamping device in a released state. [Figure 14] Figure 14 is a view from the direction of arrow XX in Figure 13. [Figure 15] Figure 15 is a modified version of the first collet, corresponding to Figure 5. [Modes for carrying out the invention]

[0029] In the description of the embodiments of the present invention, an example of using the clamping device is given in which a work pallet WP, which is the object to be clamped, is fixed to a clamp pallet CP, which is the base.

[0030] In the first embodiment of the present invention shown in Figures 1 to 12, the clamp pallet CP is supported and fixed from below by a plurality of leg members 50. The configuration of the clamp device of the first embodiment will be described based on Figures 1 to 12.

[0031] The clamping device comprises a main clamp 101 and a sub-clamp 102. The main clamp 101 and the sub-clamp 102 are fixed to the clamp pallet CP at a predetermined distance apart. Both the main clamp 101 and the sub-clamp 102 are for removably fixing the work pallet WP.

[0032] The configuration of the main clamp 101 and the sub-clamp 102 are almost identical. Let's first explain the configuration of the main clamp 101.

[0033] As shown in Figures 4 and 5, the housing 1 of the main clamp 101 is fixed to the clamp pallet CP by a plurality of bolts 2. A cylindrical plug portion 3 is integrally projected upward from the housing 1. The upper rod portion 4a of the output rod 4 (first output rod) is inserted into the plug portion cylindrical hole 3a of the plug portion 3 so as to be movable in the vertical direction (axial direction of the plug portion cylindrical hole 3a). The axial direction of the housing 1, the axial direction of the output rod 4, and the axial direction of the plug portion cylindrical hole 3a are all in the same direction.

[0034] A cylindrical hole 5 is formed on the base end side of the housing 1, and the lower rod portion 4b of the output rod 4 is inserted into the cylindrical hole 5 so as to be movable in the vertical direction. The cylindrical hole 5 is a hole with a larger diameter than the cylindrical hole 3a of the plug portion. The cylindrical hole 5 and the cylindrical hole 3a of the plug portion are formed in a vertically connected manner. The axial direction of the cylindrical hole 5 and the axial direction of the cylindrical hole 3a of the plug portion are in the same direction.

[0035] A ball 7 (sphere, rotating body) serving as an operating member (first operating member) is rotatably housed in a recess 6 (first recess) formed on the base end face of the lower rod portion 4b. A portion of the ball 7 protrudes outward in the axial direction of the cylindrical hole 5. It is also possible to use a rotating body such as a roller (not shown) instead of the ball 7 as the operating member (the same applies to the sub-clamp 102).

[0036] Furthermore, the recess 6 does not need to be formed (the same applies to the sub-clamp 102). That is, the base end face of the lower rod portion 4b may be, for example, entirely flat. In this case, the rotating body such as the ball 7 or roller is mounted and positioned on the base end face of the lower rod portion 4b in a rotatable manner via a support member (not shown).

[0037] A bottomed hole 27 (first hole) is provided in the center of the bottom of the recess 6, extending in the axial direction of the output rod 4, and a magnet 28 (first magnet) is housed at the bottom of this hole 27. The magnet 28 is fixed to the hole 27 by screwing a plug 29 as a gap-filling member beneath the magnet 28. The output rod 4, plug 29, and ball 7 are made of a magnetic material that is attracted to the magnet, such as iron. With this configuration, the magnet 28 prevents the ball 7 from falling due to gravity.

[0038] The base end of the lower rod portion 4b, where the recess 6 described above is formed, is a flange portion 8 (large diameter portion), which has a larger diameter than the other parts of the output rod 4. A spring 9 is positioned in the space above the flange portion 8 within the cylindrical bore 5 as a biasing means to push the flange portion 8 downward (towards the base end). The spring 9 is a compression coil spring. In this embodiment, the spring 9 consists of a first spring 9a and a second spring 9b. The diameter of the second spring 9b is larger than the diameter of the first spring 9a. On the upper surface (tip side) of the flange portion 8, a first stepped portion 8a that receives the lower end of the first spring 9a and a second stepped portion 8b that receives the lower end of the second spring 9b are provided in this order from the inside. A ring-shaped spring support 10 is provided on the first spring 9a to receive the upper end of the first spring 9a, and a ring-shaped spring support 11 is provided on the second spring 9b to receive the upper end of the second spring 9b. A ring-shaped stopper 12 (retaining ring) is attached to the base end of the cylindrical hole 5 to prevent the output rod 4 from coming out of the cylindrical hole 5.

[0039] Note that spring 9 is not limited to being composed of two springs. Furthermore, it is possible to use other types of springs, such as disc springs, instead of compression coil springs (the same applies to the sub-clamp 102).

[0040] Multiple through holes 13 are formed at predetermined intervals in the circumferential direction on the upper part of the peripheral wall of the plug portion 3. A ball 14 (engaging ball) is inserted into each through hole 13 as an engaging member. The through holes 13 support each ball 14 so that it can move between the radially inward position shown in Figure 1 (enlarged view in Figure 4) and the radially outward position shown in Figure 12 (outer position).

[0041] On the outer peripheral wall of the upper rod portion 4a of the output rod 4, a pressing surface 15 and a retraction groove 16 are formed vertically in a series, corresponding to each ball 14. The pressing surface 15 is formed to widen as it extends upward. When the pressing surface 15 moves to a position facing the ball 14, the ball 14 is moved to an outward position so as to protrude radially outward from the outer peripheral surface of the plug portion 3. Also, when the retraction groove 16 moves to a retracted position facing the ball 14, in which the ball 14 can be inserted, the ball 14 becomes able to move radially inward from the outer peripheral surface of the plug portion 3. In this embodiment, four balls 14 are inserted one by one into each through hole 13, but the number of balls 14 is not limited to four.

[0042] An annular collet 17 (first collet) is fitted onto the lower part (base) of the peripheral wall of the plug portion 3. The collet 17 has an outer peripheral surface 17a (tapered outer peripheral surface) that tapers upward and is elastically reduced in diameter by a single slit 17b that extends in the vertical direction. The collet 17 is prevented from coming out of the plug portion 3 by a retaining ring 18 (its upward movement is restricted). Multiple through holes 20 are formed at predetermined intervals in the circumferential direction in the upper surface 1a of the housing 1 into which a pressing member 19 that pushes the collet 17 upward (towards the tip) is inserted. The pressing member 19 is cylindrical and has a large diameter portion 19a (flange portion) at its lower end. At the large diameter portion 19a, the pressing member 19 is supported from below by a spring receiver 10. The collet 17 is biased upward by a first spring 9a via the pressing member 19 and the spring receiver 10. Therefore, the collet 17, whose upward movement is restricted by the retaining ring 18, can move slightly in the vertical direction. In this embodiment, three pressing members 19 are inserted into each through hole 20, but the number of pressing members 19 is not limited to three.

[0043] The outer circumferential surface 17a of the collet 17 is a tapered circular outer circumferential surface in a plan view. Alternatively, the outer circumferential surface 17a may be a tapered polygonal outer circumferential surface in a plan view. The main clamp 101 is configured to position the work pallet WP with respect to the axis C1 of the output rod 4 by shaping the collet 17 as described above.

[0044] A recess 21 is opened on the lower surface of the work pallet WP. A ring member 22 is fitted into the recess 21, and the ring member 22 is fixed to the work pallet WP by a plurality of bolts 23. A mounting hole 24 is formed by the inner circumference hole of the ring member 22, and the plug portion 3 can be inserted into the mounting hole 24.

[0045] The locking portion 25 in the mounting hole 24 of the ring member 22 is tapered so as it widens towards the top. Below the locking portion 25, a tapered inner circumferential surface 26 is formed that engages with the outer circumferential surface 17a of the collet 17. The tapered inner circumferential surface 26 is a surface that narrows towards the top, in other words, it is formed to become narrower as it goes upwards.

[0046] In this embodiment, the mounting hole 24 is formed in the ring member 22, but the mounting hole 24 may also be formed by the inner circumferential hole of the recess 21 of the work pallet WP. That is, the locking portion 25 and the tapered inner circumferential surface 26 may be formed in the inner circumferential hole of the recess 21 of the work pallet WP itself (the same applies to the mounting hole 24 (locking portion 25 and tapered inner circumferential surface 26) corresponding to the sub-clamp 102 described later).

[0047] The configuration of the sub-clamp 102 will be explained with reference to Figures 7 and 8. As mentioned above, the configuration of the main clamp 101 and the configuration of the sub-clamp 102 are almost the same. Therefore, in explaining the configuration of the sub-clamp 102, the differences between the sub-clamp 102 and the main clamp 101 will be explained. For each component constituting the sub-clamp 102, please refer to the above explanation of the configuration of the main clamp 101 for any components not specifically explained.

[0048] In principle, the same reference numerals are used for each component of the sub-clamp 102 as for each component of the main clamp 101. However, for each component of the sub-clamp 102, even if it is the same as a component of the main clamp 101, a different reference numeral is used simply to distinguish it from the main clamp 101.

[0049] The sub-clamp 102 consists of an output rod 30 (second output rod), a recess 31 (second recess), a ball 32 as an operating member (second operating member), a hole 34 (second hole), and a magnet 35 (second magnet), which correspond to the main clamp 101 consisting of an output rod 4 (first output rod), a recess 6 (first recess), a ball 7 as an operating member (first operating member), a hole 27 (first hole), and a magnet 28 (first magnet). Although the above components constituting the sub-clamp 102 are assigned different reference numerals than the corresponding components in the main clamp 101, the above components constituting the sub-clamp 102 are the same as the corresponding components in the main clamp 101.

[0050] Furthermore, the upper rod portion 30a and the lower rod portion 30b of the output rod 30 of the sub-clamp 102 correspond to the upper rod portion 4a and the lower rod portion 4b of the output rod 4 of the main clamp 101, respectively.

[0051] The collet 33 (second collet) that constitutes the sub-clamp 102 is the same as the collet 17 (first collet) that constitutes the main clamp 101, in that it is elastically reduced in diameter by a single slit 33b that extends in the vertical direction. On the other hand, the collet 33 differs from the collet 17 in the following respects.

[0052] Let CL be a hypothetical straight line extending from the axis C1 of the output rod 4 of the main clamp 101 to the axis C2 of the output rod 30. As shown in Figure 8 and other figures, the outer circumferential surface 33a of the collet 33 is a tapered outer circumferential surface having protrusions 36 on the side surface in the direction intersecting this straight line CL. In this embodiment, the outer circumferential surface 33a is a tapered outer circumferential surface having protrusions 36 on both sides in the direction perpendicular to the straight line CL. The sub-clamp 102 is configured to position the work pallet WP in the direction intersecting the straight line CL by shaping the collet 33 as described above.

[0053] Similar to the case of the main clamp 101, a recess 21 corresponding to the sub-clamp 102 is opened on the lower surface of the work pallet WP. A ring member 22 is mounted in the recess 21, and the ring member 22 is fixed to the work pallet WP by a plurality of bolts 23. A mounting hole 24 is formed by the inner circumference hole of the ring member 22, and the plug portion 3 can be inserted into the mounting hole 24. The configuration of the mounting hole 24 is the same as the configuration of the mounting hole 24 corresponding to the main clamp 101.

[0054] Next, the cam rod 37 will be described based on Figure 1 and other figures.

[0055] The cam rod 37 is positioned below the clamp pallet CP, with a predetermined distance between it and the clamp pallet CP. The cam rod 37 is supported from below by a linear guide 51. The rail 52 constituting the linear guide 51 is fixed to the table T, and the cam rod 37 is fixed to the upper surface of the movable member 53 constituting the linear guide 51. With this configuration, the cam rod 37 is movable along the clamp pallet CP.

[0056] The cam rod 37 comprises a rod body portion 44 and a grip portion 43 provided at the axial end of the rod body portion 44. The operator moves the cam rod 37 by, for example, grasping the grip portion 43.

[0057] A first cam groove 38 into which the ball 7 of the main clamp 101 fits, and a second cam groove 39 into which the ball 32 of the sub-clamp 102 fits are formed on the outer circumferential surface of the rod body 44. The first cam groove 38 has a first cam surface 38a for pushing the ball 7 toward the tip. The second cam groove 39 has a second cam surface 39a for pushing the ball 32 toward the tip. The first cam surface 38a and the second cam surface 39a are surfaces that are inclined in the same direction with respect to the axial direction of the rod body 44 (cam rod 37).

[0058] The first cam groove 38 and the second cam groove 39 are separated by a predetermined distance in the axial direction of the rod body 44. The distance between the first cam groove 38 and the second cam groove 39 is determined such that the ball 7 fits into the first cam groove 38 before the ball 32 fits into the second cam groove 39.

[0059] A stopper 40 is fixed to the underside of the clamp pallet CP. A groove 41 into which the tip of the stopper 40 fits is formed on the outer circumferential surface of the rod body 44. Two recesses 41a and 41b are formed in the groove 41 into which the ball 42 constituting the stopper 40 fits. Recess 41a is the recess into which the ball 42 fits when the clamping device is in the released state, and recess 41b is the recess into which the ball 42 fits when the clamping device is in the locked state.

[0060] The stopper 40 and groove 41 described above prevent the cam rod 37 from moving more than necessary and from coming off the rail 52.

[0061] The clamping device with the above configuration operates as follows:

[0062] In the released state shown in Figure 1, the outer circumferential surface of the rod body 44 (the portion where cam grooves 38, 39, and groove 41 are not formed) pushes the balls 7 and 32 upward, pushing them further into the cylindrical holes 5 of each housing 1 than in the locked state shown in Figure 12. As a result, the balls 7 and 32 push the output rods 4 and 30 upward (towards the tip) against the biasing force of the springs 9, causing them to rise. Since the output rods 4 and 30 are raised, the balls 14 of each plug section 3 can move to their retracted positions within the retracted grooves 16. The work pallet WP is loaded above the clamping device in the released state shown in Figure 1.

[0063] When clamping the work pallet WP to the clamp pallet CP, first, the work pallet WP is lowered so that each plug portion 3 is inserted into the mounting hole 24 of each ring member 22. At this time, the tapered inner circumferential surface 26 formed in each mounting hole 24 contacts the outer circumferential surface 17a of the expanded collet 17 (or the outer circumferential surface 33a of the expanded collet 33 in the case of the sub-clamp 102), creating a small gap between the upper surface 1a (seat surface) of each housing 1 and the lower surface of each ring member 22.

[0064] Subsequently, the cam rod 37 is moved along the rail 52 via the movable member 53 of the linear guide 51, thereby engaging the ball 7 in the first cam groove 38 and the ball 32 in the second cam groove 39. In Figure 1, the cam rod 37 is moved to the right in the figure.

[0065] As the cam rod 37 is moved, as shown in Figure 10, the ball 7 of the main clamp 101 is pushed by the spring 9 and moves down the first cam surface 38a of the first cam groove 38. As the cam rod 37 is moved further, as shown in Figure 11, the ball 32 of the sub-clamp 102 is pushed by the spring 9 and moves down the second cam surface 39a of the second cam groove 39. Thus, the descent of ball 7 begins earlier than the descent of ball 32, and the ball 7 of the main clamp 101 descends before the ball 32 of the sub-clamp 102.

[0066] Therefore, the main clamp 101 operates before the sub-clamp 102 as follows:

[0067] The spring 9 pushes the output rod 4 downward (towards the base end), causing the output rod 4 to descend. As the output rod 4 descends, the extrusion portion 16a, which forms part of the retraction groove 16 formed in the output rod 4, pushes the ball 14 of the plug portion 3 to a radially outward protruding position. Then, the pressing surface 15 formed in the output rod 4 presses the locking portion 25 of the work pallet WP (ring member 22) downward via the ball 14. In other words, the main clamp 101 pulls in the work pallet WP. As a result, the collet 17 shrinks in diameter and descends slightly together with the work pallet WP. Consequently, the lower surface of the ring member 22 is firmly pressed against the upper surface 1a of the housing 1, and the main clamp 101 switches from the released state shown in Figure 1 to the locked state shown in Figure 12.

[0068] At this time, since the outer circumferential surface 17a of the collet 17 is a circular, tapered outer circumferential surface in a plan view, the main clamp 101 positions and fixes the work pallet WP with respect to the axis C1 of the output rod 4.

[0069] On the other hand, the sub-clamp 102 operates with a delay compared to the main clamp 101, as follows:

[0070] The spring 9 pushes the output rod 30 downward (towards the base end), causing the output rod 30 to descend. As the output rod 30 descends, the extrusion portion 16a, which forms part of the retraction groove 16 formed on the output rod 30, pushes the ball 14 of the plug portion 3 to a radially outward protruding position. Then, the pressing surface 15 formed on the output rod 30 presses the locking portion 25 of the work pallet WP (ring member 22) downward via the ball 14. In other words, the sub-clamp 102 pulls in the work pallet WP. As a result, the collet 33 shrinks in diameter and descends slightly together with the work pallet WP. Consequently, the lower surface of the ring member 22 is firmly held in place by the upper surface 1a of the housing 1, and the sub-clamp 102 switches from the released state shown in Figure 1 to the locked state shown in Figure 12.

[0071] At this time, since the outer circumferential surface 33a of the collet 33 has a protrusion 36 on the side surface in the direction intersecting the straight line CL, the sub-clamp 102 positions and fixes the work pallet WP in the direction intersecting the straight line CL. At the sub-clamp 102 portion, the work pallet WP is not strongly constrained in the direction of the straight line CL and can move by a small amount. Therefore, while maintaining the positioning and fixing of the work pallet WP with respect to the axis C1 of the output rod 4 by the preceding main clamp 101, the work pallet WP can be positioned and fixed in the direction intersecting the straight line CL by the sub-clamp 102. In other words, the work pallet WP is locked by the main clamp 101 prior to the locking of the work pallet WP by the sub-clamp 102, so that the work pallet WP can be positioned and fixed with respect to the axis C1 of the output rod 4 with high precision.

[0072] In the locked state shown in Figure 12, there are gaps between ball 7 and the first cam groove 38, and between ball 32 and the second cam groove 39. However, even in this state, ball 7 is fitted into the first cam groove 38, and ball 32 is fitted into the second cam groove 39. Even with these gaps, the magnets 28 and 35 prevent balls 7 and 32 from falling due to gravity.

[0073] To switch the clamping device from the locked state shown in Figure 12 to the released state shown in Figure 1, the cam rod 37 is moved to the left in the diagram.

[0074] As the cam rod 37 is moved, as shown in Figure 11, first the ball 32 of the sub-clamp 102 is pushed by the second cam surface 39a, and the ball 32 moves along the second cam surface 39a and rides up onto the outer circumferential surface of the rod body portion 44 of the cam rod 37 (the portion where cam grooves 38, 39, and groove 41 are not formed). Also, as the cam rod 37 is moved, the ball 7 of the main clamp 101 is pushed by the first cam surface 38a, lagging behind the ball 32, and the ball 7 moves along the first cam surface 38a and rides up onto the outer circumferential surface of the rod body portion 44 of the cam rod 37 (the portion where cam grooves 38, 39, and groove 41 are not formed).

[0075] Here, the main clamp 101 and the sub-clamp 102 operate as follows:

[0076] Against the biasing force of each spring 9, balls 7 and 32 push output rods 4 and 30 upward (towards the tip), causing output rods 4 and 30 to rise. When output rods 4 and 30 rise, the retraction grooves 16 formed in output rods 4 and 30 come into position facing the ball 14 of the plug portion 3, allowing balls 14 to move into the retraction grooves 16 (radially inward of output rods 4 and 30). As a result, as shown in Figure 1, the work pallet WP can be smoothly removed from the clamp pallet CP. Since balls 7 and 32 rotate, when balls 7 and 32 are pressed by cam surfaces 38a and 39a, the lateral force from cam surfaces 38a and 39a can be partially relieved by balls 7 and 32, preventing twisting between the inner circumferential surface of the cylindrical hole 5 and the flange portion 8 of the output rod. As a result, output rods 4 and 30 can be moved smoothly towards the tip.

[0077] The clamping device (main clamp 101 and sub-clamp 102) does not have chambers, such as the clamping chamber and unclamping chamber found in conventional clamping devices, which supply and discharge pressurized fluid with each operation. In this clamping device, the output rods 4 and 30 can be driven in the tip direction of the axial direction via balls 7 and 32 by moving the cam rod 37 manually or by external force. In the other axial direction, towards the base end, the output rods 4 and 30 are driven by springs 9. Therefore, this clamping device does not require pressurized fluid such as compressed air to be driven.

[0078] Figures 13 and 14 show a second embodiment of the present invention. In the clamping device of the second embodiment, the clamp pallet CP is movable and the cam rod 37 is fixed. This is the difference between the clamping device of the second embodiment and the clamping device of the first embodiment. Note that the same reference numerals are used for the same components as those in the clamping device of the first embodiment for each component constituting the clamping device of the second embodiment.

[0079] The clamp pallet CP is supported from below by a linear guide 51. The rails 52 that make up the linear guide 51 are fixed to the table T, and the clamp pallet CP is fixed to the upper surface of the movable member 53 that makes up the linear guide 51. With the above configuration, the clamp pallet CP is movable (transportable) on the table T.

[0080] Since the cam rod 37 is fixed to the table T and does not move, it does not have the grip portion 43 in the first embodiment.

[0081] In the clamping device of the first embodiment, the clamping device (main clamp 101 and sub-clamp 102) is locked or released by moving the cam rod 37, whereas in the clamping device of the second embodiment, the clamping device (main clamp 101 and sub-clamp 102) is locked or released by moving the clamp pallet CP.

[0082] Except for the difference between the movement of the cam rod 37 and the movement of the clamp pallet CP, the operation of the clamping device (main clamp 101 and sub-clamp 102) in the second embodiment is the same as in the first embodiment. The clamp pallet CP is moved manually or by external force. When the clamp pallet CP is moved manually or by external force, the output rod 4 of the main clamp 101 is driven via the ball 7, and the output rod 30 of the sub-clamp 102 is driven via the ball 32.

[0083] Figure 15 shows a modified example of the collet 17 (first collet). The outer circumferential surface 17a of the collet 17 is a tapered outer circumferential surface having three protrusions 45 arranged at equal intervals from each other in the circumferential direction. In this embodiment, the shape of the collet 17 is configured to position the work pallet WP with respect to the axis C1 of the output rod 4. Note that the number of protrusions 45 is not limited to three. Four or more protrusions 45 may be arranged at equal intervals from each other on the outer circumferential surface 17a (side surface) in the circumferential direction.

[0084] In the clamping devices of the first and second embodiments, a spring 9 is placed inside each cylindrical hole 5 of the main clamp 101 and sub-clamp 102 (the space above the flange portion 8 of the cylindrical hole 5), and the spring 9 pushes and moves the output rods 4 and 30 toward the base end. Alternatively, the space above the flange portion 8 of each cylindrical hole 5 may be used as a pressurized gas chamber, and the gas pressure in the pressurized gas chamber may push and move the output rods 4 and 30 toward the base end. A pressurized gas chamber is a chamber filled with pressurized gas. The pressurized gas chamber is sealed to the outside so that the pressurized gas does not leak out of the chamber. The pressurized gas filled in each pressurized gas chamber acts as a biasing means to replace the spring 9, pushing and moving the output rods 4 and 30 toward the base end. The pressurized gas can be compressed air, compressed nitrogen gas, etc.

[0085] As described above, each pressure gas chamber is sealed to prevent pressure gas from leaking to the outside of the chamber. However, when the output rods 4 and 30 are driven by the filled pressure gas, a small amount of pressure gas may leak out of the pressure gas chamber. Therefore, in order to maintain the gas pressure in the pressure gas chamber necessary to move the output rods 4 and 30, the main clamp 101 and sub-clamp 102 should be configured so that only the amount of compressed air that has leaked out of the pressure gas chamber is filled into the pressure gas chamber.

[0086] The compressed gas chamber will be supplied with the amount of compressed gas that leaks from the chamber, but the amount of compressed gas used will be extremely small. Therefore, although compressed gas supply equipment such as an air compressor is necessary, the scale of such equipment can be extremely small.

[0087] The present invention is not limited to the embodiments described above, and it is possible to combine elements of the embodiments as appropriate or to make various modifications to the embodiments without departing from the spirit of the invention.

[0088] For example, the above embodiment can be modified as follows:

[0089] In the clamping devices of the first and second embodiments, ball 7 fits into the first cam groove 38 prior to ball 32 fitting into the second cam groove 39, thereby locking the work pallet WP by the main clamp 101 prior to locking the work pallet WP by the sub-clamp 102. Alternatively, ball 7 may be pushed into the cylindrical hole 5 of the sub-clamp 101 by the first cam surface 38a prior to ball 32 being pushed into the cylindrical hole 5 of the sub-clamp 102 by the second cam surface 39a (moved toward the tip side), thereby locking the work pallet WP by the main clamp 101 prior to locking the work pallet WP by the sub-clamp 102.

[0090] In this case, the main clamp 101 and the sub-clamp 102 are configured such that the output rods 4 and 30 move toward the tip side to lock the work pallet WP, and the output rods 4 and 30 move toward the base side to release the work pallet WP.

[0091] In the above embodiment, a protrusion 36 is provided on the outer circumferential surface (side surface) of the collet 33 as part of the configuration of the sub-clamp 102 for positioning the work pallet WP in a direction intersecting the straight line CL. Alternatively, a protrusion equivalent to the protrusion 36 may be provided on the tapered inner circumferential surface 26 formed in the mounting hole 24 on the clamping object (work pallet WP) side, which engages with the outer circumferential surface of the collet 33.

[0092] The means to prevent the balls 7 and 32 from falling, such as magnets 28 and 35, may be omitted. In the locked state shown in Figure 12, if the gap between ball 7 and the first cam groove 38, and between ball 32 and the second cam groove 39 are small, the balls 7 and 32 will not fall (come loose).

[0093] The orientation of the clamping device may be inverted, oriented sideways, or even at an angle, relative to the exemplified up-and-down orientation.

[0094] The clamping device may be fixed to a table or the like. The object to be clamped may be a workpiece, mold, tool, or jig. [Explanation of symbols]

[0095] 1: Housing, 3: Plug section, 4: First output rod (output rod), 5: Cylinder hole, 6: Recess (first recess), 7: Ball (first operating member), 9: Spring (biasing means), 13: Through hole, 14: Ball (engaging member), 17: Collet (first collet), 17a: Outer surface, 24: Mounting hole, 25: Locking section, 27: Hole (first hole), 28: Magnet (first magnet), 30: Second output rod (output rod), 31: Recess (second recess), 32: Ball (Second operating member), 33: Collet (second collet), 33a: Outer surface, 34: Hole (second hole), 35: Magnet (second magnet), 36: Protrusion, 37: Cam rod, 38: First cam groove, 38a: First cam surface, 39: Second cam groove, 39a: Second cam surface, 45: Protrusion, 101: Main clamp, 102: Sub-clamp, CP: Clamp pallet (base), WP: Work pallet (object to be clamped), C1: Axis, C2: Axis, CL: Imaginary straight line

Claims

1. A main clamp (101) and a sub-clamp (102) are fixed to a base (CP) at a predetermined interval, and the main clamp (101) and sub-clamp (102) are provided to removably fix the object to be clamped (WP), The main clamp (101) and the sub-clamp (102) are, respectively, A housing (1) fixed to the base (CP), An output rod (4, 30) is inserted into the housing (1) so as to be movable in the axial direction of the housing (1), A cylindrical hole (5) formed on the base end side of the housing (1), into which the output rod (4, 30) is inserted so as to be movable in the axial direction, An operating member (7, 32) is rotatably positioned on the base end face of the output rod (4, 30), and the operating member (7, 32) pushes and moves the output rod (4, 30) in the tip direction of the axial direction, A biasing means (9) is positioned inside the cylindrical hole (5) or filled inside the cylindrical hole (5) and pushes the output rod (4, 30) toward the base end in the axial direction, It has, The main clamp (101) is configured to position the object to be clamped (WP) with reference to the axis (C1) of the first output rod (4) which constitutes the main clamp (101), The sub-clamp (102) is configured to position the object to be clamped (WP) in a direction intersecting a virtual straight line (CL) extending from the axis (C1) to the axis (C2) of the second output rod (30) which constitutes the output rod of the sub-clamp (102). The cam rod (37), which is positioned at a predetermined distance from the base (CP), has a first cam groove (38) formed on its outer surface into which the first operating member (7), which constitutes the main clamp (101), fits, and a second cam groove (39) formed on its outer surface into which the second operating member (32), which constitutes the sub-clamp (102), fits. The first cam groove (38) has a first cam surface (38a) for pushing the first operating member (7) toward the tip side, The second cam groove (39) has a second cam surface (39a) for pushing the second operating member (32) toward the tip side, Prior to the second operating member (32) fitting into the second cam groove (39), the first operating member (7) fits into the first cam groove (38), thereby locking the clamped object (WP) by the main clamp (101) prior to the locking of the clamped object (WP) by the sub-clamp (102). The operating members (7, 32) are arranged to rotate in accordance with the movement of the cam rod (37) when the cam rod (37) is movable along the base (CP), and are arranged to rotate in accordance with the movement of the base (CP) when the cam rod (37) is fixed and the base (CP) is movable. Clamping device.

2. In the clamping device of claim 1, The main clamp (101) and the sub-clamp (102) are, respectively, A cylindrical plug portion (3) protruding from the housing (1), An annular collet (17, 33) fitted onto the plug portion (3), the collet (17, 33) being elastically reduced in diameter, It has, The outer circumferential surface (17a) of the first collet (17) which constitutes the main clamp (101) is a tapered outer circumferential surface that is circular or polygonal in plan view, or a tapered outer circumferential surface having at least three protrusions (45) on its side at equal intervals from one another in the circumferential direction. The outer circumferential surface (33a) of the second collet (33) which constitutes the sub-clamp (102) is a tapered outer circumferential surface having a convex portion (36) on the side surface in a direction intersecting the straight line (CL). Clamping device.

3. In the clamping device according to claim 1 or 2, A first recess (6) and a second recess (31) are formed on the base end face of the first output rod (4) and the base end face of the second output rod (30), respectively. The first operating member (7) is housed in the first recess (6) in a rotatable manner, and the second operating member (32) is housed in the second recess (31) in a rotatable manner. Clamping device.

4. In the clamping device according to claim 1 or 2, The cam rod (37) is movable along the base (CP). Clamping device.

5. In the clamping device according to claim 1 or 2, The first operating member (7) and the second operating member (32) are spheres or rollers. Clamping device.

6. In the clamping device of claim 3, A first hole (27) and a second hole (34) are provided in the center of the bottom of the first recess (6) and the second recess (31), respectively. The device further comprises a first magnet (28) and a second magnet (35) housed in the first hole (27) and the second hole (34), respectively. The first output rod (4), the second output rod (30), the first operating member (7), and the second operating member (32) are formed of a magnetic material that is attracted to a magnet. Clamping device.

7. In the clamping device according to claim 1 or 2, The biasing means (9) is a spring (9). Clamping device.

8. In the clamping device according to claim 1 or 2, The main clamp (101) and the sub-clamp (102) are, respectively, A cylindrical plug portion (3) protruding from the housing (1), An engaging member (14) is inserted into a through hole (13) formed in the peripheral wall of the plug portion (3), and is moved within the through hole (13) as the output rod (4, 30) moves in the axial direction, and is able to abut against a locking portion (25) of a mounting hole (24) provided in the clamp object (WP) so that the plug portion (3) can be inserted, Having, Clamping device.

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