Lock unit and level corrector

Abstract

A lock unit (22) comprises: a first bush (28) through which a rod (20) extending in the axial direction is inserted; a second bush (30) which is disposed so as to be spaced apart from the first bush (28) in the axial direction and through which the rod (20) is inserted; and a lock mechanism (42) which presses a braking member against the rod (20) in the direction intersecting the axial direction between the first bush (28) and the second bush (30) so as to generate a holding force between the rod (20) and each of the first bush (28) and the second bush (30).

Description

Lock Unit and Level Corrector

[0001] The present disclosure relates to a lock unit and a level corrector.

[0002] In a robot transfer system, a level corrector that causes the position of a suction pad to follow the shape of a workpiece is used to grip an inclined workpiece (Japanese Patent Application Laid-Open No. 2001-271858). By using the level corrector, a tilting operation of a robot arm is unnecessary, and tact time can be shortened. Further, the level corrector can simplify the operation of the robot arm and eliminate the need for teaching to cope with tilting.

[0003] In the level corrector, a large number of lock units that hold rods are arranged side by side. In order to further reduce the size and weight of the level corrector, it is desired to reduce the diameter and weight of the lock unit.

[0004] However, when the diameter of the lock unit is reduced, there is a problem that the holding force for the rod is reduced, which imposes a restriction on the weight of a workpieces that can be gripped.

[0005] An object of the present disclosure is to solve the above-described problem.

[0006] A first aspect of the present disclosure is a lock unit including: a first bush through which a rod extending in an axial direction is inserted; a second bush spaced apart from the first bush in the axial direction, through which the rod is inserted; and a lock mechanism that presses a braking member against the rod in a direction intersecting the axial direction between the first bush and the second bush.

[0007] A second aspect of the present disclosure is a level corrector including a plurality of lock units according to the first aspect, with rods inserted therethrough.

[0008] The lock unit of the present disclosure can achieve both a reduced diameter and a high holding force, and enables reduction in size and weight of the level corrector.

[0009] The above objects, features and advantages will be readily understood from the following description of embodiments described with reference to the accompanying drawings.

[0010] Figure 1 is an explanatory diagram of the transfer system according to the first embodiment. Figure 2 is a perspective view of the lock unit according to the first embodiment. Figure 3 is a cross-sectional view along the line III-III in Figure 2. Figure 4A is a cross-sectional view along the line IV-IV in Figure 2 in the unlocked state, and Figure 4B is a cross-sectional view along the line IV-IV in Figure 2 in the locked state. Figure 5 is a perspective view of the locking mechanism of the lock unit in Figure 2. Figure 6A is a perspective view showing the locking mechanism of the lock unit according to the second embodiment, and Figure 6B is a cross-sectional view of the lock unit according to the second embodiment. Figure 7A is a perspective view showing the locking mechanism of the lock unit according to the third embodiment, and Figure 7B is a cross-sectional view of the lock unit according to the third embodiment. Figure 8 is a perspective view of the lock unit according to the fourth embodiment. Figure 9 is a cross-sectional view along the line IX-IX in Figure 8. Figure 10A is a perspective view of the locking mechanism of the lock unit in Figure 8, and Figure 10B is an exploded perspective view of the contact member and biasing member in Figure 10A. Figure 11A is a cross-sectional view along line XI-XI in Figure 8 in the locked state, and Figure 11B is a cross-sectional view along line XI-XI in Figure 8 in the unlocked state. Figure 12 is a cross-sectional view of the lock unit according to the fifth embodiment. Figure 13A is a cross-sectional view along line XIII-XIII in Figure 12 in the unlocked state, and Figure 13B is a cross-sectional view along line XIII-XIII in Figure 12 in the locked state.

[0011] (First Embodiment) As shown in Figure 1, the transfer system 10 according to this embodiment includes a plurality of suction pads 12, a level compensator 14 that supports the suction pads 12, a hand 16 that holds the level compensator 14, and a robot arm 18 that drives the hand 16. The suction pads 12 adhere to the surface of the workpiece W by negative pressure supplied through negative pressure piping (not shown). The level compensator 14 includes a plurality of sets of rods 20 that support the suction pads 12 and locking units 22 that can lock the rods 20.

[0012] The transfer system 10 operates as follows: First, the transfer system 10 drives the robot arm 18 to position multiple level correctors 14 on the workpiece W, which has inclines and uneven surfaces. Then, the transfer system 10 controls each lock unit 22 to release the lock on the rod 20. Releasing the lock allows the rod 20 to be displaced. With the lock released, the transfer system 10 drives the robot arm 18 to press the multiple rods 20 against the workpiece W.

[0013] As a result, the suction pads 12 come into contact with the surface of the workpiece W and stop. Multiple suction pads 12 are arranged to conform to the surface of the workpiece W, and the level (height) of the suction pads 12 is corrected according to the position on the surface of the workpiece W. Then, the transfer system 10 drives each lock unit 22 of the level corrector 14 to lock the rod 20 in the stop position. Next, the transfer system 10 supplies negative pressure to the suction pads 12 to pick up the workpiece W and drives the robot arm 18 to transfer the workpiece W to a predetermined location.

[0014] Such a transfer system 10 is suitable for use in automated equipment lines in factories and the like. The level corrector 14 of this embodiment is equipped with a plurality of miniaturized lock units 22. The lock units 22 of this embodiment will be described below.

[0015] As shown in Figure 2, the locking unit 22 has a roughly rectangular parallelepiped housing 24 that extends long in the axial direction. The housing 24 extends, for example, with the same dimensions in the width direction and depth direction perpendicular to the axial direction.

[0016] As shown in Figures 2 and 3, the housing 24 comprises a through hole 26, a first bush 28, a second bush 30, a cylinder chamber 32, and a cover member 34. The through hole 26 is located at the center of the housing 24 in the width and depth directions and extends axially. The through hole 26 penetrates the housing 24 axially and opens at the first end 24a and the second end 24b of the housing 24, respectively. The through hole 26 intersects with and communicates with the cylinder chamber 32 near the axial center. A rod 20 is inserted through the through hole 26.

[0017] The through hole 26 has a first bush mounting portion 26a, a second bush mounting portion 26b, a first small diameter portion 26c, and a second small diameter portion 26d. The first bush mounting portion 26a is provided adjacent to the first end portion 24a. The first bush 28 is attached to the first bush mounting portion 26a. The second bush mounting portion 26b is provided adjacent to the second end portion 24b. The second bush 30 is attached to the second bush mounting portion 26b.

[0018] The first small-diameter portion 26c is provided between the first bush mounting portion 26a and the cylinder chamber 32. The first small-diameter portion 26c has a smaller inner diameter than the first bush mounting portion 26a. The inner diameter of the first small-diameter portion 26c is larger than the outer diameter of the rod 20, and the first small-diameter portion 26c is configured not to come into contact with the rod 20 even in the locked state.

[0019] The second small-diameter portion 26d is provided between the second bush mounting portion 26b and the cylinder chamber 32. The second small-diameter portion 26d has a smaller inner diameter than the second bush mounting portion 26b. The inner diameter of the second small-diameter portion 26d is larger than the outer diameter of the rod 20, and the second small-diameter portion 26d is configured not to come into contact with the rod 20 even in the locked state.

[0020] The first bush 28 is located at the first end 24a of the housing 24 and is fitted into the first bush mounting portion 26a. The first bush 28 is a cylindrical member extending in the axial direction and supports the cylindrical rod 20 and functions as a bearing that guides the displacement direction of the rod 20 in the axial direction. The first bush 28 is formed from a relatively hard material such as metal, resin, or ceramics.

[0021] The first bush 28 has an inner diameter that allows the rod 20 to slide smoothly in the axial direction. However, when the rod 20 is deflected by the locking mechanism 42 described later, the edges 28a at both ends of the first bush 28 in the axial direction bite into the outer surface of the rod 20, thereby generating a higher holding force than when the rod 20 is held solely by the frictional force of the braking member.

[0022] The second bush 30 is located at the second end 24b of the housing 24 and is spaced apart from the first bush 28 in the axial direction. The second bush 30 is fitted into the second bush mounting portion 26b. The second bush 30 is formed in the same shape as the first bush 28 using the same material. The second bush 30 functions as a bearing that allows the rod 20 to slide smoothly in the axial direction. Furthermore, when the rod 20 is bent, the edges 30a at both ends of the second bush 30 in the axial direction bite into the outer circumferential surface of the rod 20, thereby providing a higher holding force than when the rod 20 is held solely by the frictional force of the braking member.

[0023] The cylinder chamber 32 is located in the axial center of the housing 24. The cylinder chamber 32 extends in a depth direction perpendicular to the axial direction and intersects with the rod 20. The end of the cylinder chamber 32 in the first depth direction is closed by the cover member 34. The end of the cylinder chamber 32 in the second depth direction is closed by the second side surface 24d of the housing 24. The cylinder chamber 32 intersects with and communicates with the insertion hole 26. The insertion hole 26 has an opening 26e on the inner surface of the cylinder chamber 32. The rod 20 is inserted into the cylinder chamber 32 in the axial direction through the opening 26e. The cylinder chamber 32 also houses the lock piston 36 and the return spring 38 inside.

[0024] The cylinder chamber 32 can be formed in an oval shape, with its axial dimension being larger than its width dimension, in order to accommodate a lock piston 36 of sufficient area. The cylinder chamber 32 is formed in an oval shape capable of accommodating the lock piston 36 shown in Figure 5.

[0025] A cover member 34 is attached to the first side surface 24c located at the first end in the depth direction of the housing 24. The cover member 34 covers and closes the end of the cylinder chamber 32. A lock port 40 is formed in the cover member 34 for supplying and discharging compressed air to drive the lock piston 36. An air pipe (not shown) is connected to the lock port 40.

[0026] As shown in Figure 4A, the lock unit 22 includes a lock piston 36 and a return spring 38 as a lock mechanism 42. The lock piston 36 is a braking member in this embodiment. As shown in Figure 5, the lock piston 36 is formed in an elongated oval shape that extends long in the axial direction. As shown in Figure 4A, the lock piston 36 has a packing 36a, a groove 36b, and a spring receiving hole 36c.

[0027] The packing 36a is attached to the outer circumference of the lock piston 36. The packing 36a hermetically seals the gap between the inner surface of the cylinder chamber 32 and the lock piston 36. Therefore, the lock piston 36 hermetically separates the cylinder chamber 32 into a first region 32a through which the rod 20 is inserted and a second region 32b that communicates with the lock port 40.

[0028] The groove 36b is a groove with a circular arc cross-section having the same radius of curvature as the outer diameter of the rod 20, and is formed on the surface of the lock piston 36 facing the rod 20. The groove 36b extends in the axial direction and accommodates the rod 20. The groove 36b comes into contact with the rod 20 when the lock piston 36 is displaced to the locked position.

[0029] A pair of spring receiving holes 36c are arranged on both sides in the width direction of the groove 36b. The spring receiving holes 36c house the end of the return spring 38, thereby holding the return spring 38 in the appropriate position and receiving the elastic force of the return spring 38. The return spring 38 is the return member in this embodiment. The return spring 38 is a coil spring, and the end of the return spring 38 in the second direction abuts against the end of the cylinder chamber 32 in the second direction. The return spring 38 biases the lock piston 36 in the second direction by its elastic force. When compressed air is not supplied to the lock port 40, the lock piston 36 moves away from the rod 20 by the elastic force of the return spring 38.

[0030] The lock unit 22 of this embodiment is configured as described above. The operation of the lock unit 22 will now be explained.

[0031] When compressed air is not supplied to the lock port 40 of the lock unit 22 (for example, open to the atmosphere), as shown in Figure 4A, the lock piston 36 is biased in the direction away from the rod 20 (first direction) by the elastic force of the return spring 38. The rod 20 can be displaced by smoothly inserting it through the first bush 28 and the second bush 30. In other words, the lock unit 22 is in an unlocked state when compressed air is not supplied to the lock port 40.

[0032] When compressed air is supplied to the second region 32b through the lock port 40, the pressure in the second region 32b increases, and the lock piston 36 is displaced in the second direction in the depth direction along the cylinder chamber 32, as shown in Figure 4B. When compressed air of sufficient pressure is supplied to the second region 32b, the lock piston 36 comes into contact with the rod 20. The lock piston 36 generates frictional force through surface contact between the groove 36b and the rod 20.

[0033] As shown in Figure 5, when compressed air is supplied, the first bush 28 and the second bush 30 act as fulcrums on the rod 20, and the lock piston 36 acts as the point of application, applying a bending load to the rod 20 from the first direction to the second direction. When compressed air above a predetermined pressure is supplied, the lock piston 36 bends the rod 20, and the edges 28a of the first bush 28 and the edges 30a of the second bush 30 bite into the outer surface of the rod 20. As a result, the rod 20 and the first bush 28 and the second bush 30 become locked together, generating a strong holding force in the axial direction of the rod 20. The lock unit 22 of this embodiment can generate a relatively strong holding force on the rod 20 with a simple configuration. Therefore, the lock unit 22 can achieve both a small diameter and a strong holding force. In some applications, the rod 20 may not require such strong holding force. In such cases, the locking unit 22 may be supplied with compressed air at a pressure that does not cause the rod 20 to gnaw against the first bush 28 and the second bush 30.

[0034] (Second Embodiment) The lock unit 22A of this embodiment, shown in Figures 6A and 6B, is constructed by replacing the oval-shaped lock piston 36 in the lock mechanism 42 of the first embodiment shown in Figure 5 with a circular first sub-piston 46 (braking member) and a second sub-piston 48 (braking member). In the lock unit 22A of this embodiment, components similar to those in the lock unit 22 of the first embodiment are denoted by the same reference numerals, and their detailed descriptions are omitted.

[0035] The first sub-piston 46 is formed in a circular shape when viewed from the depth direction. A packing 46a is provided on the outer circumference of the first sub-piston 46. A groove 46b for accommodating the rod 20 is formed on the surface of the first sub-piston 46 facing the rod 20. The groove 46b is a semicircular groove with a bottom surface having a radius of curvature approximately the same as the outer diameter of the rod 20, and extends in the axial direction. A pair of spring receiving holes 46c are formed on both sides of the groove 46b in the width direction. The ends of the return spring 38 (return member) are accommodated in the spring receiving holes 46c.

[0036] The second sub-piston 48 is formed in a circular shape when viewed from the depth direction. A packing 48a is provided on the outer circumference of the second sub-piston 48. A groove 48b for accommodating the rod 20 is formed on the surface of the second sub-piston 48 facing the rod 20. The groove 48b is a semicircular groove with a bottom surface having a radius of curvature approximately the same as the outer diameter of the rod 20, and extends in the axial direction. A pair of spring receiving holes 48c are formed on both sides of the groove 48b in the width direction. The ends of the return spring 38 are accommodated in the spring receiving holes 48c.

[0037] The first sub-piston 46 is housed in the first sub-cylinder chamber 50 of the housing 24, and the second sub-piston 48 is housed in the second sub-cylinder chamber 52. The first ends of the first sub-cylinder chamber 50 and the second sub-cylinder chamber 52 are covered by a cover member 34. The lock port 40 of the cover member 34 communicates with the first sub-cylinder chamber 50 and the second sub-cylinder chamber 52.

[0038] In this embodiment, when compressed air is not supplied to the lock port 40, the first sub-piston 46 and the second sub-piston 48 separate from the rod 20 due to the elastic force of the return spring 38, resulting in an unlocked state. When compressed air is supplied to the lock port 40, the first sub-piston 46 and the second sub-piston 48 flex the rod 20, resulting in a locked state. The lock unit 22A of this embodiment provides the same effects as the lock unit 22 of the first embodiment.

[0039] (Third Embodiment) The lock unit 22B of this embodiment shown in Figures 7A and 7B is provided with a plurality of locking mechanisms 42 in the axial direction. That is, in addition to the locking mechanism 42 of the first embodiment, a second locking mechanism 42A and a third locking mechanism 42B are further added. In the lock unit 22B of this embodiment, the same reference numerals are used for components similar to those in the lock unit 22 of the first embodiment, and their detailed descriptions are omitted.

[0040] As shown in Figure 7B, the housing 24 further comprises a second cylinder chamber 32A, a third cylinder chamber 32B, a second cover member 70, and a third cover member 75.

[0041] The second cylinder chamber 32A is located near the first end 24a of the housing 24. The second cylinder chamber 32A extends in the depth direction and intersects with the insertion hole 26. The end of the second cylinder chamber 32A in the second direction is covered by the second cover member 70. The second cover member 70 has a second lock port 40A formed therein.

[0042] The third cylinder chamber 32B is located near the second end 24b of the housing 24. The third cylinder chamber 32B extends in the depth direction and intersects with the insertion hole 26. The end of the third cylinder chamber 32B in the second direction is covered by the third cover member 75. A third lock port 40B is formed in the third cover member 75.

[0043] The second lock mechanism 42A is provided in the second cylinder chamber 32A. The second lock mechanism 42A includes a second lock piston 62 (braking member) and a return spring 381 (return member). The second lock piston 62 is disposed on a side portion of the rod 20 in the second direction. The second lock piston 62 is slidably accommodated in the depth direction in the second cylinder chamber 32A. When compressed air is supplied from the second lock port 40A, the second lock piston 62 is displaced in the first direction and pressed against the rod 20. The return spring 381 is disposed on the first direction side of the second lock piston 62, and biases the second lock piston 62 in the second direction. In a state where compressed air is not supplied, the return spring 381 displaces the second lock piston 62 in the second direction to separate it from the rod 20.

[0044] The third lock mechanism 42B is provided in the third cylinder chamber 32B. The third lock mechanism 42B includes a third lock piston 64 (braking member) and a return spring 382 (return member). The third lock piston 64 is disposed on a side portion of the rod 20 in the second direction. The third lock piston 64 is slidably accommodated in the depth direction in the third cylinder chamber 32B. When compressed air is supplied from the third lock port 40B, the third lock piston 64 is displaced in the first direction and pressed against the rod 20. The return spring 382 is disposed on the first direction side of the third lock piston 64, and biases the third lock piston 64 in the second direction. In a state where compressed air is not supplied, the return spring 382 displaces the third lock piston 64 in the second direction to separate it from the rod 20.

[0045] The lock unit 22B enters a locked state when compressed air is supplied to the lock port 40, the second lock port 40A, and the third lock port 40B. That is, the lock mechanism 42 presses the lock piston 36 in the second direction. The second lock mechanism 42A, which is adjacent to one side of the lock mechanism 42, presses the second lock piston 62 in the first direction, which is opposite to the direction in which the lock mechanism 42 presses. Further, the third lock mechanism 42B, which is adjacent to the other side of the lock mechanism 42, presses the third lock piston 64 in the first direction, which is opposite to the direction in which the lock mechanism 42 presses.

[0046] Accordingly, the lock unit 22B of the present embodiment can generate a frictional force against the rod 20 with three braking members, and can reliably hold the rod 20.

[0047] (Fourth Embodiment) The lock unit 22C of the present embodiment shown in Fig. 8 includes a substantially rectangular parallelepiped housing 24 that extends long in the axial direction. The housing 24 extends, for example, with the same dimensions in the width direction orthogonal to the axial direction and in the depth direction.

[0048] As shown in Fig. 8 and Fig. 9, the housing 24 includes an insertion hole 26, a first bush 28, a second bush 30, a cylinder chamber 32C, and a cover member 34. The insertion hole 26 is located at the center of the housing 24 in the width direction and the depth direction, and extends in the axial direction. The insertion hole 26 penetrates the housing 24 in the axial direction, and opens at a first end 24a and a second end 24b of the housing 24, respectively. The insertion hole 26 communicates with the cylinder chamber 32C near the center in the axial direction. The rod 20 is inserted through the insertion hole 26.

[0049] The insertion hole 26 includes a first bush mounting portion 26a, a second bush mounting portion 26b, a first small-diameter portion 26c, and a second small-diameter portion 26d. The first bush mounting portion 26a is provided adjacent to the first end 24a. The first bush 28 is mounted to the first bush mounting portion 26a. The second bush mounting portion 26b is provided adjacent to the second end 24b. The second bush 30 is mounted to the second bush mounting portion 26b.

[0050] The first small-diameter portion 26c is provided between the first bush mounting portion 26a and the cylinder chamber 32C. The first small-diameter portion 26c has an inner diameter smaller than that of the first bush mounting portion 26a. However, the inner diameter of the first small-diameter portion 26c is larger than the outer diameter of the rod 20, and the first small-diameter portion 26c is configured so as not to contact the rod 20 even in the locked state.

[0051] The second small-diameter portion 26d is provided between the second bush mounting portion 26b and the cylinder chamber 32C. The second small-diameter portion 26d has a smaller inner diameter than the second bush mounting portion 26b. The inner diameter of the second small-diameter portion 26d is larger than the outer diameter of the rod 20, and the second small-diameter portion 26d is configured not to come into contact with the rod 20 even in the locked state.

[0052] The first bush 28 is located at the first end 24a of the housing 24 and is fitted into the first bush mounting portion 26a. The first bush 28 is a cylindrical member extending in the axial direction, supporting the cylindrical rod 20 and guiding the displacement direction of the rod 20 in the axial direction. The first bush 28 is formed from a relatively hard material such as metal, resin, or ceramics.

[0053] The first bush 28 has an inner diameter that allows the rod 20 to slide smoothly in the axial direction. However, when the rod 20 is deflected by the locking mechanism 42C described later, the first bush 28, in part or in whole, generates a strong frictional force against the rod 20, preventing smooth sliding and thus locking the rod 20. In a particularly limited embodiment, the first bush 28 may be provided with edges 28a at both ends in the axial direction. The edges 28a can generate a higher holding force by biting into the outer circumferential surface of the rod 20 when the rod 20 is deflected.

[0054] The second bush 30 is located at the second end 24b of the housing 24 and is spaced apart from the first bush 28 in the axial direction. The second bush 30 is fitted into the second bush mounting portion 26b. The second bush 30 is formed in the same shape as the first bush 28 using the same material. The second bush 30 allows the rod 20 to slide smoothly in the axial direction and generates a strong frictional force against the rod 20 when the rod 20 is bent. The second bush 30 may have edges 30a at both ends in the axial direction that can bite into the outer circumferential surface of the rod 20.

[0055] The cylinder chamber 32C is located in the axial center of the housing 24. The cylinder chamber 32C extends in a depth direction perpendicular to the axial direction. The end of the cylinder chamber 32C in the first depth direction is closed by the cover member 34. The end of the cylinder chamber 32C in the second depth direction is closed by the second side surface 24d of the housing 24. The cylinder chamber 32C houses the fourth release piston 76 and the fourth contact member 78 inside.

[0056] The cylinder chamber 32C has a large-diameter portion 33 and a housing recess 81. The large-diameter portion 33 is formed in an oval shape that extends long in the longitudinal direction when viewed from the depth direction in order to accommodate the fourth release piston 76 of sufficient area. The large-diameter portion 33 houses the fourth release piston 76 so that it can slide in the depth direction. The housing recess 81 is formed in a circular shape when viewed from the depth direction and extends in a second direction from the large-diameter portion 33. The housing recess 81 houses the fourth contact member 78 so that it can be displaced in the depth direction.

[0057] A cover member 34 is attached to the first side surface 24c located at the first end in the depth direction of the housing 24. The cover member 34 covers and closes the end of the cylinder chamber 32C. The cover member 34 has a release port 40C formed therein for supplying and discharging compressed air to drive the fourth release piston 76. An air pipe (not shown) is connected to the release port 40C.

[0058] The lock unit 22C of this embodiment includes a fourth release piston 76, a fourth contact member 78, and a fourth biasing member 80 as the lock mechanism 42C. The fourth release piston 76 is housed in the large diameter portion 33, and the fourth contact member 78 and the fourth biasing member 80 are housed in the housing recess 81.

[0059] As shown in Figure 10A, the fourth release piston 76 is formed in an oval shape when viewed from the depth direction. The fourth release piston 76 has a fourth packing 76a, a fourth groove 76b, and a fourth pressing surface 76c. The fourth packing 76a is attached to the outer circumference of the fourth release piston 76. As shown in Figure 9, the fourth release piston 76 having the fourth packing 76a airtightly partitions the large-diameter portion 33 of the cylinder chamber 32C into a first region 32a and a second region 32b. The second region 32b communicates with the release port 40C.

[0060] As shown in Figure 10A, the fourth groove 76b of the fourth release piston 76 is a groove formed by cutting out the end of the fourth release piston 76 in the second direction, and extends in the axial direction. As shown in Figure 11A, the fourth groove 76b is formed in a position where its width is greater than the diameter of the rod 20 and it does not come into contact with the rod 20. Furthermore, the depth of the fourth groove 76b is formed to a depth that does not come into contact with the rod 20 even when the fourth release piston 76 reaches the stroke end in the second direction. Therefore, the fourth groove 76b accommodates the rod 20 without coming into contact with it.

[0061] The fourth pressing surface 76c of the fourth release piston 76 is the end face of the fourth release piston 76 in the second direction. The fourth pressing surface 76c is formed on both sides in the width direction of the fourth groove 76b. The fourth pressing surface 76c contacts the fourth contact member 78 and presses the fourth contact member 78 in the second direction.

[0062] As shown in Figures 10A, 10B, and 11A, the fourth contact member 78 is positioned on the side of the fourth release piston 76 in the second direction in the depth direction. The fourth contact member 78 sandwiches the rod 20 between itself and the fourth release piston 76. The fourth contact member 78 has a fourth contact groove 78a, a fourth contact surface 78b, and a fourth step portion 78c. The fourth contact groove 78a is a groove formed by cutting out the end of the fourth contact member 78 in the first direction in a circular arc cross-section, and extends in the axial direction with the same cross-sectional shape. The fourth contact groove 78a has a bottom surface with the same radius of curvature as the outer surface of the rod 20, and is configured to be able to make surface contact with the outer surface of the rod 20. The fourth contact groove 78a is formed to be shallower in the depth direction than the fourth groove 76b. The fourth contact groove 78a contacts the rod 20 in the locked state, causing the rod 20 to elastically deform.

[0063] The fourth contact surface 78b is the end face of the fourth contact member 78 in the first direction and is formed on both sides in the width direction of the fourth contact groove 78a. The fourth contact surface 78b receives the biasing force of the fourth release piston 76 by contacting the fourth pressing surface 76c of the fourth release piston 76. The fourth step portion 78c is formed at the end of the fourth contact member 78 in the second direction. The fourth step portion 78c engages with the fourth biasing member 80. The fourth step portion 78c has a fourth column portion 78d that protrudes short from the center of the fourth contact member 78 toward the bottom of the cylinder chamber 32C. The fourth step portion 78c is inserted into the hole of the fourth biasing member 80 and holds the fourth biasing member 80 in the appropriate position.

[0064] The fourth biasing member 80 is a disc spring formed from a disc-shaped metal plate with a hole in the center, shaped into a cone. The fourth biasing member 80 is positioned between the fourth stage portion 78c of the fourth contact member 78 and the end of the cylinder chamber 32C in the second direction. The fourth biasing member 80 biases the fourth contact member 78 toward the rod 20 by its elastic force. When the fourth release piston 76 is not being driven, the fourth contact member 78 biases the rod 20 laterally, causing it to bend.

[0065] The lock unit 22C of this embodiment is configured as described above. The operation of the lock unit 22C will be described below.

[0066] In the lock unit 22C, if compressed air is not supplied to the release port 40C, the fourth contact member 78, which receives the elastic force of the fourth biasing member 80, is pressed against the rod 20, as shown in Figure 11A. This generates a frictional force between the fourth contact groove 78a of the fourth contact member 78 and the rod 20. Since the fourth biasing member 80 can generate a high elastic force, it can deform the rod 20 so that it bends. As a result, the edge 28a of the first bush 28 and the edge 30a of the second bush 30 can bite into the outer surface of the rod 20 and twist it. This allows the lock unit 22C to generate a greater holding force and firmly lock the rod 20 (locked state).

[0067] On the other hand, when compressed air is supplied to the release port 40C, the fourth release piston 76 is displaced in the second direction, as shown in Figure 11B. The driving force of the fourth release piston 76 displaces the fourth contact member 78 in the second direction against the elastic force of the fourth biasing member 80. As a result, the fourth contact member 78 separates from the rod 20, and the deflection of the rod 20 is released. This allows the rod 20 to smoothly pass through the first bush 28 and the second bush 30. In other words, the lock unit 22C is released by supplying compressed air to the release port 40C.

[0068] In this embodiment, the locking unit 22C generates a holding force on the rod 20 by the elastic force of the fourth biasing member 80. According to the locking unit 22C of this embodiment, a strong holding force can be generated on the rod 20 with a simple configuration. Therefore, the locking unit 22C can achieve both a small diameter and a strong holding force.

[0069] (Fifth Embodiment) The lock unit 22D of this embodiment shown in Figures 12, 13A, and 13B differs from the lock unit 22C of the fourth embodiment in that the lock mechanism 42D becomes locked when compressed air is supplied.

[0070] The locking unit 22D includes a fifth locking piston 114, a fifth release member 116, and a fifth biasing member 118 as the locking mechanism 42D. The parts other than the locking mechanism 42D are basically the same as those of the locking unit 22C of the fourth embodiment. In this embodiment, the release port 40C of the locking unit 22C is referred to as the locking port 40, but the structure is the same. In addition, in the configuration of the locking unit 22D of this embodiment, the same reference numerals are used for parts that are common with the locking unit 22C of the fourth embodiment, and their detailed description is omitted.

[0071] The fifth locking piston 114 is housed in the large-diameter portion 33 of the cylinder chamber 32C, and the fifth release member 116 and the fifth biasing member 118 are housed in the housing recess 81D.

[0072] The fifth lock piston 114 is formed in an oval shape similar to the fourth release piston 76 shown in Figure 10A. The fifth lock piston 114 has a fifth packing 114a, a fifth contact groove 114b, and a fifth contact portion 114c. The fifth packing 114a is attached to the outer circumference of the fifth lock piston 114. The fifth packing 114a seals the gap between the inner circumference of the cylinder chamber 32C and the outer circumference of the fifth lock piston 114 by being in close contact with the inner circumference of the large diameter portion 33.

[0073] The fifth contact groove 114b is a groove with a semicircular cross-section formed by cutting out the end of the fifth lock piston 114 in the second direction, and extends in the axial direction. The fifth contact groove 114b has an inner surface having the same radius of curvature as the outer surface of the rod 20. The fifth contact groove 114b accommodates a portion of the rod 20. When the fifth lock piston 114 is displaced to the locked position, the fifth contact groove 114b makes surface contact with the outer surface of the rod 20, generating a holding force on the rod 20.

[0074] The fifth contact portion 114c is the end face of the fifth lock piston 114 in the second direction. The fifth contact portion 114c is provided on both sides in the width direction of the fifth contact groove 114b. The fifth contact portion 114c is the part that contacts the fifth release member 116 and receives the biasing force of the fifth release member 116.

[0075] The fifth locking piston 114 airtightly separates the cylinder chamber 32C into a first region 32a through which the rod 20 is inserted and a second region 32b that communicates with the locking port 40. When compressed air is supplied to the locking port 40, the fifth locking piston 114 is displaced in the second direction, biasing the rod 20 and generating a holding force.

[0076] The fifth release member 116 is a cylindrical member having the same outer diameter and height (dimension in the depth direction) as the fourth contact member 78. The fifth release member 116 is housed in the housing recess 81 of the cylinder chamber 32C so as to be displaceable in the depth direction. The fifth release member 116 is positioned on the side of the fifth lock piston 114 in the second direction in the depth direction and sandwiches the rod 20 between itself and the fifth lock piston 114.

[0077] The fifth release member 116 has a fifth groove 116a, a fifth pressing portion 116b, and a fifth spring receiving hole 116c. The fifth groove 116a is formed by cutting out a concave shape from the end of the fifth release member 116 in the first direction and extends in the axial direction. The fifth groove 116a is formed in a U shape when viewed from the axial direction, and its width dimension is larger than the diameter of the rod 20. Furthermore, the fifth groove 116a has a depth such that it does not come into contact with the rod 20 even when the fifth release member 116 reaches the maximum displacement range in the first direction. In other words, the fifth groove 116a accommodates the rod 20 without coming into contact with it.

[0078] The fifth pressing portion 116b is the end face of the fifth release member 116 in the first direction. The fifth pressing portion 116b is formed on both sides in the width direction of the fifth groove 116a. The fifth pressing portion 116b presses against the fifth contact portion 114c of the fifth lock piston 114, thereby biasing the fifth lock piston 114 in a direction that separates it from the rod 20.

[0079] The fifth spring receiving hole 116c is formed in the center of the second-direction end of the fifth release member 116. The fifth spring receiving hole 116c accommodates the first-direction end of the fifth biasing member 118, thereby holding the fifth biasing member 118 in the appropriate position.

[0080] The end of the fifth biasing member 118 in the second direction is housed in the sixth spring receiving hole 81a at the bottom of the housing recess 81. The fifth biasing member 118 is, for example, a coil spring and biases the fifth release member 116 toward the first direction. The elastic force of the fifth biasing member 118 is strong enough to push the fifth lock piston 114 back to the release position when compressed air is not supplied to the lock port 40.

[0081] The lock unit 22D of this embodiment is configured as described above. The operation of the lock unit 22D will be described below.

[0082] In the lock unit 22D, if compressed air is not supplied to the lock port 40, as shown in Figure 13A, the fifth release member 116, which receives the elastic force of the fifth biasing member 118, displaces the fifth lock piston 114 in the first direction. As a result, the fifth lock piston 114 is maintained in the released position. In the released position, the fifth lock piston 114 is separated from the rod 20, and the rod 20 can be displaced axially without being subjected to a large frictional force.

[0083] On the other hand, when compressed air is supplied to the lock port 40, the fifth lock piston 114 is displaced in the second direction against the elastic force of the fifth biasing member 118, as shown in Figure 13B. The fifth lock piston 114 contacts the rod 20 and presses it in the second direction. As a result, the fifth lock piston 114 is pressed against the rod 20, generating a frictional force between the fifth contact groove 114b and the rod 20. Furthermore, when compressed air at a predetermined pressure or higher is supplied to the lock port 40, the fifth lock piston 114 deforms the rod 20 so that it bends. In this case, in addition to the frictional force between the rod 20 and the fifth lock piston 114, the edge 28a of the first bush 28 or the edge 30a of the second bush 30 bites into the rod 20, creating a twisted state and generating a greater holding force. As a result, the rod 20 is locked (locked state).

[0084] As described above, the lock unit 22D of this embodiment can generate a relatively strong holding force on the rod 20 with a simple configuration. Therefore, the lock unit 22D can achieve both a small diameter and a strong holding force. Furthermore, the lock unit 22D can be converted to the lock unit 22C of the fourth embodiment simply by replacing the fifth lock piston 114 and the fifth release member 116, making it advantageous in that most of the parts are common.

[0085] With regard to the above embodiments, the following additional information is disclosed.

[0086] (Note 1) One embodiment of a locking unit (22, 22A, 22B, 22C, 22D) comprises a first bush (28) through which an axially extending rod (20) is inserted, a second bush (30) positioned spaced apart from the first bush in the axial direction and through which the rod is inserted, and a locking mechanism (42, 42C, 42D) between the first bush and the second bush that presses a braking member against the rod in a direction intersecting the axial direction.

[0087] The above-mentioned locking unit can generate high holding force on the rod while maintaining a small diameter.

[0088] (Note 2) The locking unit described in Note 1 may include a cylinder chamber (32, 32C) intersecting the rod, a locking piston (36, 114) disposed in the cylinder chamber and acting as the braking member, and a release member (116) that separates the locking piston from the rod. This locking unit can generate a large holding force with a simple structure.

[0089] (Note 3) The locking unit described in Note 1 may include a cylinder chamber that intersects with the rod, a contact member (78) as a braking member disposed in the cylinder chamber, a biasing member (80) that biases the contact member toward the rod and presses the contact member against the rod, and a release piston (76) disposed in the cylinder chamber that separates the contact member from the rod. This locking unit can press the contact member against the rod with a constant load regardless of the compressed air pressure and can generate a stable holding force.

[0090] (Note 4) A locking unit according to any one of Notes 1 to 3, wherein the locking mechanism may include a plurality of sub-pistons (46, 48) arranged in the axial direction as the braking member. This locking unit makes it possible to reduce the diameter of the piston.

[0091] (Note 5) A locking unit according to any one of Notes 1 to 4, wherein a plurality of the locking mechanisms are provided in the axial direction, and adjacent locking mechanisms press the braking member against the rod in opposite directions. This locking unit can generate a higher holding force by bending the rod more.

[0092] (Note 6) A locking unit according to any one of Notes 1 to 5, wherein the first bush and the second bush may have edges (28a, 30a) that bite into the outer surface of the rod when the rod is bent. This locking unit can generate a higher holding force on the rod by twisting the first bush, the second bush and the rod.

[0093] (Note 7) The locking unit described in Note 3 may have a disc spring as the biasing member. This locking unit can provide a high biasing force to the contact member, thus enabling both miniaturization and high holding force.

[0094] (Note 8) A level compensator (14) in one embodiment comprises a plurality of locking units described in any one of Notes 1 to 7 through which the rod is inserted. By comprising the above-mentioned locking units, this level compensator is made smaller and lighter.

[0095] While this disclosure has been described in detail, it is not limited to the individual embodiments described above. These embodiments can be added, replaced, modified, partially deleted, etc., in any way that does not depart from the gist of this disclosure or from the spirit of this disclosure derived from the claims and their equivalents. These embodiments can also be implemented in combination. For example, the order of operations and processes in the embodiments described above are given as examples only and are not limited thereto. The same applies when numerical values ​​or mathematical formulas are used in the description of the embodiments described above.

Claims

1. A locking unit (22, 22A, 22B, 22C, 22D) comprising: a first bush (28) through which a rod (20) extending in the axial direction is inserted; a second bush (30) positioned spaced apart from the first bush in the axial direction and through which the rod is inserted; and a locking mechanism (42, 42C, 42D) between the first bush and the second bush that presses a braking member against the rod in a direction intersecting the axial direction.

2. A locking unit according to claim 1, wherein the locking mechanism comprises: a cylinder chamber (32, 32C) intersecting the rod; a locking piston (36, 114) disposed in the cylinder chamber and acting as the braking member; and a release member (116) that separates the locking piston from the rod.

3. A locking unit according to claim 1, wherein the locking mechanism comprises: a cylinder chamber intersecting the rod; a contact member (78) disposed in the cylinder chamber as a braking member; a biasing member (80) that biases the contact member toward the rod, thereby pressing the contact member against the rod; and a release piston (76) disposed in the cylinder chamber for separating the contact member from the rod.

4. A locking unit according to any one of claims 1 to 3, wherein the locking mechanism comprises a plurality of sub-pistons (46, 48) arranged in the axial direction as the braking member.

5. A locking unit according to any one of claims 1 to 4, wherein a plurality of the locking mechanisms are provided in the axial direction, and adjacent locking mechanisms press the braking member against the rod from opposite directions.

6. A locking unit according to any one of claims 1 to 5, wherein the first bush and the second bush have edges (28a, 30a) that bite into the outer surface of the rod when the rod is bent.

7. A locking unit according to claim 3, wherein the biasing member is a disc spring.

8. A level compensator (14) comprising a plurality of locking units according to any one of claims 1 to 7 through which a rod is inserted.

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