JP5474608B2 - Clamping device - Google Patents

Description

  The present invention relates to a clamping device for gripping and fixing the inner peripheral surface of a hole in a workpiece, and a clamping member is forcibly moved to a unclamping side by forcibly moving a piston member of a driving means for driving the grip member to expand its diameter. A clamp forcible release means for releasing

  Conventionally, various clamping devices (so-called hole clamp or expansion clamp) for gripping the inner peripheral surface of the hole of the workpiece as described above have been put to practical use. For example, in the clamping devices described in Patent Literatures 1 and 2, a grip member having a grip claw portion that vertically penetrates the insertion hole of the upper body member of the clamp body and a plurality of teeth is formed, A clamp rod for expanding the diameter of the grip member, a hydraulic cylinder for driving the clamp rod to be clamped, and a support mechanism for supporting the grip member with the elastic force of the compression spring for expanding the diameter of the grip member are provided.

  By the way, the above-described clamping device is a hydraulic clamping device configured such that the clamp rod is clamp-driven by the hydraulic pressure supplied to the clamping-side oil chamber of the hydraulic cylinder. A spring-type clamp device that is clamp-driven by the urging forces of a plurality of compression springs is also in practical use. The drive means of the spring clamp device includes a piston member connected to the clamp rod, a spring accommodating chamber for accommodating the compression spring, an unclamping oil chamber to which unclamping hydraulic pressure is supplied.

  Further, the support mechanism of the hydraulic clamp device is a spring type that supports the grip member with the elastic force of the compression spring at the time of the diameter expanding drive for expanding the grip member. Instead, a clamp device having a hydraulic support mechanism that supports the grip member with hydraulic pressure has been put to practical use.

  On the other hand, in the above clamping device, the grip member and the upper half portion of the clamp rod are structured to extend upward through the insertion hole of the upper body member. For this reason, a flexible scraper that closes the annular gap so as to prevent foreign matter such as chips from entering the inside from the annular gap on the outer peripheral side of the grip member and the clamp rod in the insertion hole is clamp body. The clamping device provided in is also known.

German Patent No. 4020981 JP-A-11-188551

  By the way, in the above hydraulic and spring clamp devices, the grip claw portion of the grip member bites into the inner peripheral surface of the hole of the workpiece and is engaged by frictional force, so that there is a problem that the grip claw portion is easily worn. . For this reason, it is necessary to replace the grip member when the grip claw is worn, but the grip member has a structure in which the upper body member of the clamp body is provided in a penetrating manner, so that the upper body member must be removed from the clamp body. The grip member cannot be replaced. There is also a clamp device with a hydraulic support mechanism in the clamp body as described above, so when replacing the grip member, it is possible to work by draining all the hydraulic pressure in the clamp device in consideration of oil leakage. desirable.

  However, in the case of a spring-type clamp device, when the hydraulic pressure is discharged, the piston member is clamp-driven by the urging force of the compression spring, the clamp device is in a clamped state, and the grip member is in an expanded diameter state. If an attempt is made to replace the grip member in this clamped state, the inner peripheral portion of the scraper is pressed toward the outer diameter increasing side due to the diameter expansion drive of the grip member, and the upper body member is compressed in the annular gap. If it is attempted to forcibly remove, the upper body member may be caught by the scraper and damaged, and the durability of the scraper may be significantly reduced.

Thus, in the spring-type clamp device, when the hydraulic pressure is discharged, it becomes a clamped state, the upper body member cannot be easily removed, and the grip member cannot be easily replaced.
Similarly, when the hydraulic pressure in the unclamping oil chamber leaks into the spring housing chamber and the hydraulic pressure in the unclamping oil chamber does not rise, it becomes impossible to release the clamp, and it is impossible to repair the clamping device such as replacing the seal member. . That is, there is a problem that maintenance of the clamping device takes time.

  An object of the present invention is to provide a clamping device provided with forced unclamping means that can be unclamped without using hydraulic pressure, to provide a clamping device that can easily replace a grip member, and the like. .

  The clamp device according to claim 1 is a clamp body, a grip member capable of gripping the inner peripheral surface of the hole of the workpiece, a clamp rod engaged with the grip member, and driving the clamp rod forward and backward with respect to the clamp body. In the clamping device, the driving means includes a piston member mounted in a cylinder hole of the clamp body, one or a plurality of compression springs for biasing the piston member toward the clamp side, and the piston member. An unclamping fluid chamber that is supplied with a fluid pressure that urges the unclamping side to the unclamping side, and includes a screw member that can be driven back and forth in the axial direction of the clamp rod with respect to the clamp body, Forced unclamp capable of forcibly pressing the piston member toward the unclamp side via the screw member without using the fluid pressure in the chamber It is characterized in that a means.

  According to a second aspect of the present invention, in the first aspect of the present invention, the clamp body includes a bottom wall member that closes an end opposite to the piston member of the unclamping fluid chamber, and the forced unclamping means includes the A screw hole formed in the bottom wall member in communication with the unclamping fluid chamber and closed by a detachable plug member is provided, and the screw member is used as a screw hole in a state where the bottom wall member is opened to the outside. It is characterized in that it is screwed and the tip of the screw member is brought into contact with the piston portion of the piston member and pressed toward the unclamp side.

  According to a third aspect of the present invention, there is provided the clamping device according to the first aspect, wherein the forced unclamping means includes a pair of engaging portions formed on an outer peripheral portion of the clamp body and a pair engageable with the engaging portions. And a screw hole formed in a connecting beam portion of the gate-shaped member to which the screw member can be screwed, an outer peripheral portion of the clamp body, the unclamping fluid chamber, and the The screw member is screwed into the screw hole in a state where the piston portion of the piston member is opened to the outside and the distal end portions of the pair of leg portions of the portal member are engaged with the pair of engaging portions. In addition, it is characterized in that the tip end portion of the screw member is brought into contact with the piston portion and pressed toward the unclamp side.

  According to a fourth aspect of the present invention, in the invention of the third aspect, the engaging portion is formed of an annular groove or a pair of concave portions.

  According to a fifth aspect of the present invention, in the first aspect of the invention, the clamp device includes a support mechanism that supports the grip member with a fluid pressure for expanding the diameter of the grip member, and the support mechanism supports a proximal end of the grip member. And a support fluid chamber for applying fluid pressure to the proximal end of the annular piston portion of the annular pressure receiving member.

  According to a sixth aspect of the present invention, in the first aspect of the present invention, the clamp device includes a support mechanism that supports the grip member with fluid pressure for expanding the diameter of the grip member, and the support mechanism is movable on the rod portion of the piston member. An annular pressure receiving member that is externally fitted, a support member having a base end supported by the annular pressure receiving member and supporting the base end of the grip member, and fluid pressure applied to the base end of the annular piston portion of the annular pressure receiving member. It is characterized by having a support fluid chamber that acts.

  According to the first aspect of the present invention, the forced unclamping means can forcibly press the piston portion toward the unclamping side via the screw member without using the fluid pressure of the unclamping fluid chamber. The clamping device can be released from the clamp against the biasing force of the compression spring. Therefore, the grip member can be easily removed from the clamp body and replaced, so that the maintenance of the clamp device can be easily performed.

  According to the second aspect of the present invention, the forced unclamping means includes a screw hole that is formed in the bottom wall member in communication with the unclamping fluid chamber and that can be opened and closed via the plug member, and the bottom wall member is placed outside. In the open state, the screw member is screwed into the screw hole, and the tip end portion of the screw member is brought into contact with the piston portion and pressed toward the unclamp side. The clamp device can be unclamped by moving to the unclamp side.

  According to the invention of claim 3, the forced unclamping means has a gate shape having a pair of engaging portions formed on the outer peripheral portion of the clamp body and a pair of legs engageable with these engaging portions. A member and a screw hole formed in a connecting beam portion of the gate-shaped member to which a screw member can be screwed, the outer peripheral portion of the clamp body, the fluid chamber for unclamping, and the piston portion are opened to the outside and the gate-shaped member In a state where the tip portions of the pair of leg portions are engaged with the pair of engaging portions, the screw member is screwed into the screw hole and the tip portion of the screw member is brought into contact with the piston portion to unclamp. Since it is configured to press to the side, the clamping device can be unclamped by moving the piston portion to the unclamping side by rotating the screw member.

  According to invention of Claim 4, since an engaging part consists of an annular groove or a pair of recessed part, this engaging part can be easily formed in the outer peripheral part of a clamp main body, and with respect to the existing clamp apparatus. Thus, this forced unclamping means can be easily applied.

  According to the invention of claim 5, the support mechanism includes the annular pressure receiving member that supports the proximal end of the grip member, and the support fluid chamber that applies fluid pressure to the proximal end of the annular piston portion of the annular pressure receiving member. The diameter of the grip member can be reliably increased by supporting the grip member with the fluid pressure of the support mechanism.

  According to the sixth aspect of the present invention, the support mechanism includes an annular pressure receiving member movably fitted on the rod portion of the piston member, a proximal end portion supported by the annular pressure receiving member, and a proximal end of the grip member. Since the support fluid chamber for applying fluid pressure to the base end of the annular piston portion of the support member and the annular pressure receiving member is provided, the diameter of the grip member can be reliably increased by supporting the grip member with the fluid pressure of the support mechanism.

It is a top view of the clamp device concerning Example 1 of the present invention. It is sectional drawing of a clamp apparatus (unclamped state). It is sectional drawing of a clamp apparatus (clamp state). It is sectional drawing of a clamp apparatus (forced unclamp state). It is a top view of the clamp device concerning Example 2. It is sectional drawing of a clamp apparatus (unclamped state). It is sectional drawing of a clamp apparatus (clamp state). It is sectional drawing of a clamp apparatus (full stroke state). It is sectional drawing of a clamp apparatus (forced unclamp state). It is sectional drawing of the clamp apparatus (forced unclamp state) which concerns on Example 3. FIG.

  Hereinafter, modes for carrying out the present invention will be described based on examples.

  As shown in FIGS. 1 to 4, the clamp device C includes a clamp body 1, a grip member 2, a clamp rod 3, a driving means 4 that drives the clamp rod 3 forward and backward, and a support. A mechanism 7 and a forced unclamping means 9 are included. The clamp body 1 is composed of an upper body member 11 and a lower body member 12, and the clamp body 1 is inserted into the mounting hole 13a of the base body member 13 and assembled. Although the mounting hole 13a of the base body member 13 is formed in a penetrating shape, it is not particularly limited to this and may be formed in a bottomed shape.

  The upper body member 11 is a substantially rectangular steel member in plan view. The upper body member 11 is fixed to the base body member 13 with four bolts inserted into the four bolt holes 14. The lower main body member 12 is a cylindrical member that forms a cylinder hole 41, and the upper end portion of the lower main body member 12 is fitted into the concave portion 15 on the lower surface side of the upper main body member 11 and fixed by four bolts 16. Yes.

  The grip member 2 is disposed so as to vertically pass through the insertion hole 17 in the central portion of the upper end portion of the upper main body member 11. An annular seating surface 18 surrounding the grip member 2 is formed on the upper surface of the upper main body member 11, and the workpiece W is seated on these seating surfaces 18 in a state where the workpiece W is clamped. Except for the annular seating surface 18, the upper surface of the upper body member 11 is formed as a partial conical surface having a gentle inclination angle.

  As shown in FIGS. 2 to 4, the grip member 2 is inserted into the hole of the workpiece W through the insertion hole 17 in the upper end portion of the clamp body 1 together with the clamp rod 3, and grips the inner peripheral surface of the hole. Is possible. The grip member 2 has a rod insertion hole 21 for inserting the clamp rod 3, a cylindrical grip claw portion 22, and a proximal end flange portion 23, and the grip member 2 can be enlarged or reduced in radius. In order to be able to be expanded and contracted and to be disassembled, it is divided into four equal parts by four slits and bundled by an O-ring 27.

  On the outer peripheral surface of the grip claw portion 22 of the grip member 2, two-step teeth that make it easy to grip the inner peripheral surface of the hole formed in the workpiece W are formed. The grip claw portion corresponding portion of the rod insertion hole 21 is formed in a tapered hole portion 24 in which the tapered shaft portion 31 of the clamp rod 3 is engaged in close contact.

  As shown in FIGS. 1 to 4, a scraper 26 is mounted in the insertion hole 17 of the upper main body member 11, and the scraper 26 closes an annular gap on the outer peripheral side of the grip member 2 and foreign matter such as chips is contained inside. To prevent intrusion. The scraper 26 is made of an elastic material such as rubber or synthetic resin that is in sliding contact with the outer peripheral surface of the grip member 2. An O-ring 27 for urging the grip member 2 divided into four in the diameter reducing direction is attached to the lower portion of the grip member 2.

  The base end flange 23 of the grip member 2 is accommodated in the circular recess 29 of the upper body member 11 and is movably sandwiched between the upper wall portion of the circular recess 29 and the horizontal plate portion 74 of the annular pressure receiving member 71. Yes. The grip member 2 can be moved up and down by a small distance integrally with the annular pressure receiving member 71 by the driving means 4, and the axial center of the clamping device C is formed via the annular clearance on the outer periphery of the circular recess 29 and the elastic deformation of the scraper 26. It is mounted so that it can be moved by a small distance in the horizontal direction perpendicular to.

  The clamp rod 3 is formed by integrally forming a tapered shaft portion 31, a small diameter rod portion 32, a large diameter rod portion 33, and a large diameter flange portion 34. The tapered shaft portion 31 and the small diameter rod portion 32 are inserted into the rod insertion hole 21 of the grip member 2. The taper shaft portion 31 is formed at the upper end portion of the clamp rod 3 so as to increase in diameter upward, and the taper shaft portion 31 is fitted and engaged with the taper hole portion 24 of the grip member 2. An O-ring 36 is mounted in an annular groove on the outer periphery of the large-diameter rod portion 33, and the O-ring 36 is mounted in a slightly compressed state between the large-diameter rod portion 33 and the upper end wall portion of the cylindrical piston rod 44. Yes.

Next, the driving means 4 will be described.
As shown in FIGS. 2 to 4, the driving means 4 drives the clamp rod 3 to move up and down in the vertical direction with respect to the clamp body 1, and clamps and drives the hydraulic pressure of the hydraulic cylinder by the elastic force of the compression spring. The clamp release drive.

  The drive means 4 includes a longitudinal cylinder hole 41 formed in the lower main body member 12, a piston member 42 mounted in the cylinder hole 41, and an annular shape formed above the piston portion 43 of the piston member 42. A spring accommodating chamber 45; a compression spring 46 that is accommodated in the spring accommodating chamber 45 and strongly elastically urges the piston member 42 toward the clamp side; and is formed below the piston member 42 and the piston member 42 is unclamped An unclamping oil chamber 47 (corresponding to an unclamping fluid chamber) to which hydraulic pressure urging (upward) is supplied is provided. The compression spring 46 for clamping is made of a spring steel wire having a rectangular cross section, but may be made of a spring steel wire having a circular cross section.

  The piston member 42 has a piston portion 43 and a cylindrical piston rod 44 extending upward from the piston portion 43. About 2/3 of the total length from the middle step portion to the lower end of the cylindrical piston rod 44 is formed in a large-diameter large-diameter rod portion 51, and a spring accommodating chamber 45 is provided on the outer peripheral side of the large-diameter rod portion 51. Is formed. One compression spring 46 is mounted in the spring accommodating chamber 45 in a compressed state to urge the piston member 42 downward. FIG. 2 shows an unclamped state. In this unclamped state, the upper end portion of the large-diameter rod portion 51 is locked by the locking portion 56 of the lower main body member 12. A small-diameter rod portion 52 is formed so as to continue above the large-diameter rod portion 51.

  The piston portion 43 of the piston member 42 is received by the bottom wall member 61 and becomes the lower limit position. The outer peripheral portion of the piston portion 43 is oil-tightly sealed with a seal member 43a. The piston member 42 is formed with a small-diameter hole 53 at the upper end, an intermediate-diameter hole 54 extending over substantially the entire length of the cylindrical piston rod 44, and a large-diameter hole 55 at the lower end. The large diameter rod portion 51 of the clamp rod 3 is located in the small diameter hole 53, and the large diameter flange portion 34 is located at the upper end in the medium diameter hole 54.

  An oil passage forming member 57 having a large vertical length is mounted on most of the medium diameter hole 54 and the large diameter hole 55 of the piston member 42, and the oil passage forming member 57 is in contact with the lower end of the clamp rod 3. The lower end portion of the oil passage forming member 57 is prevented from coming off by a stop ring 58. The outer periphery of the oil passage forming member 57 is oil-tightly sealed with seal members 57a to 57c. The middle stage portion of the oil passage forming member 57 is formed to have a smaller diameter than the upper and lower end portions, and an annular space 59 is formed between the piston member 42 and the middle diameter hole 54, and the spring accommodating chamber 45 via the insertion hole 59 a. It is communicated to. The lower end portion of the oil passage forming member 57 constitutes a part of the piston portion 43.

  Between the upper end member of the cylindrical piston rod 44 and the upper end portion of the oil passage forming member 57, a large-diameter flange portion 34 is mounted so as to be movable in the horizontal direction. There is a slight gap between the outer peripheral surface of the large diameter flange 34 and the inner peripheral surface of the medium diameter hole 54. Therefore, the clamp rod 3 moves up and down integrally with the piston member 42, and the clamp rod 3 moves with the grip member 2 relative to the piston member 42 in the horizontal direction perpendicular to the axis of the clamp device C. Is only movable.

  The lower main body member 12 of the clamp body 1 includes a bottom wall member 61 that closes an end of the unclamping oil chamber 47 opposite to the piston member 42. The outer peripheral portion of the bottom wall member 61 is oil-tightly sealed with a seal member 61 a, is prevented from coming off with a stop ring 62, and is restricted by a rotation restricting pin 63. A screw hole 64 to be described later and a head accommodation hole 65 that accommodates the head of the plug member 66 are formed in the central portion of the bottom wall member 61. A plug member 66 is detachably screwed into the screw hole 64 and the head receiving hole 65 to close the screw hole 64. The head receiving hole 65 is oil-tightly sealed with a seal member 65a.

  The unclamping oil chamber 47 is formed by the cylinder hole 41, the piston portion 43, and the bottom wall member 61, and through an oil passage 67 formed in the lower body member 12 and an oil passage 68 formed in the base body member 13. And connected to a hydraulic pressure supply source (not shown). The outer peripheral portion of the lower main body member 12 is oil-tightly sealed with a plurality of seal members. The upper inner peripheral portion of the lower main body member 12 is oil-tightly sealed with a plurality of seal members 12d and 12e.

Next, the support mechanism 7 will be described.
As shown in FIGS. 2 to 4, the support mechanism 7 supports the grip member 2 with hydraulic pressure in order to increase the diameter of the grip member 2. The support mechanism 7 includes an annular pressure receiving member 71 that supports the base end (lower end) of the grip member 2, and an annular support oil chamber 72 that applies hydraulic pressure to the base end (lower end) of the annular piston portion 73 of the annular pressure receiving member 71. (Support fluid chamber). The annular pressure receiving member 71 has an annular piston portion 73 and a horizontal plate portion 74 connected to the upper end of the annular piston portion 73, and the base end flange portion 23 of the grip member 2 is placed and supported on the upper surface of the horizontal plate portion 74. Has been.

  The upper body member 11 is formed with a receiving hole 76 that is continuous with the upper end of the cylindrical cylinder hole 75. The depth of the accommodation hole 76 is slightly larger than the thickness from the upper end of the horizontal plate portion 74 to the lower end of the locking collar portion 73a. The lower half portion of the annular piston portion 73 is slidably mounted in a cylindrical cylinder hole 75 formed by the lower body member 12 and the cylindrical piston rod 44 so as to be slidable in the vertical direction. The horizontal flat plate portion 74 is movably mounted in the accommodation hole 76 in the vertical direction. The inner peripheral side of the annular piston portion 73 is sealed with a seal member 73b, and the outer peripheral side is sealed with a seal member 12d. The clamp rod 3 is inserted into a circular hole 77 at the center of the horizontal plate portion 74 in a loosely fitting manner, and a locking collar 73 a having a slightly larger diameter than the annular piston portion 73 is formed on the outer peripheral portion of the annular piston portion 73. Is formed.

  A support oil chamber 72 for receiving hydraulic pressure upward is formed at the lower end of the annular piston portion 73 at the lower end of the cylindrical cylinder hole 75. The support oil chamber 72 is connected to the unclamping oil chamber 47 via the oil passage 81 of the small-diameter rod portion 52 of the cylindrical piston rod 44 and the throttle oil passage 82 and the oil passage 83 in the oil passage forming member 57. ing. The support oil chamber 72 is supplied with hydraulic pressure from the unclamping oil chamber 47 in the unclamped state, and the hydraulic pressure in the support oil chamber 72 is discharged through the throttle oil passage 82 over a predetermined minute time from the start of the clamping operation. Drain pressure is reached.

  The throttle oil passage 82 functions to delay the discharge of the hydraulic pressure from the support oil chamber 72 after the start of the clamping operation, and to release the entire hydraulic pressure of the support mechanism 7 after the diameter of the grip member 2 is expanded. In addition, after the clamping operation is started, the clamping force gradually increases as the support force gradually decreases, and reaches the maximum clamping force over the predetermined minute time. The maximum clamping force is reached by the start of machining on the workpiece W.

  A seating sensor for detecting that the lower surface of the workpiece W is in close contact with the seating surface 18 is provided. As shown in FIG. 1, the seating sensor is formed in the upper body member 11 and the lower body member 12 so as to communicate with the pressurized air ejection hole 84 opened in the seating surface 18 and the pressurized air ejection hole 84. Air passage 85, a pressurized air supply source (not shown) connected to the air passage 85, and a pressure switch (not shown) for detecting that the pressure of the pressurized air in the air passage 85 has risen above a set pressure. ) Etc. Further, a cleaning passage 87 for cleaning the grip member 2, the clamp rod 3, the seating surface 18 and the like by air blow is also provided in the upper main body member 11.

Next, the forced unclamping means 9 will be described.
As shown in FIG. 4, the forced unclamping means 9 is for forcibly releasing the clamping device C. The forced unclamping means 9 includes a screw hole 64 formed in the bottom wall member 61 in communication with the unclamping oil chamber 47 and closed by a removable plug member 66, and the clamp rod 3 with respect to the clamp body 1. And a screw member 91 that can be driven back and forth in the axial direction.

  In a state where the clamp main body 1 is removed from the base main body member 13 and the removable plug member 66 is removed from the bottom wall member 61, the screw member 91 is inserted and screwed into the screw hole 64, and the tip end portion (upper end portion) thereof is engaged. The piston portion 43 (oil passage forming member 57) is brought into contact with the piston portion 43. An operation portion 92 capable of rotating the screw member 91 is integrally provided at the base end portion (lower end portion) of the screw member 91. The screw member 91 is advanced and retracted in the axial direction of the clamp rod 3 by the rotation of the operation portion 92. Instead of providing the operation portion 92 at the base end portion of the screw member 91, a tool may be connected to the screw member 91 to rotate the screw member 91.

  In this way, the forced unclamping means 9 removes the clamp body 1 from the base body member 13, removes the detachable plug member 66 from the bottom wall member 61, and opens the bottom wall member 61 to the outside. Without using the hydraulic pressure of the oil chamber 47 for clamping, the screw member 91 is screwed into the screw hole 64 and the tip of the screw member 91 is brought into contact with the piston portion 43, and the piston portion 43 is moved through the screw member 91. It is configured to be able to forcibly press toward the unclamp side.

Next, the operation of the clamping device C of the present invention will be described.
When the workpiece W is clamped by the clamping device C, first, hydraulic pressure is supplied to the unclamping oil chamber 47 and an upward hydraulic pressure is applied to the piston portion 43. Then, against the biasing force of the compression spring 46 in the spring accommodating chamber 45, as shown in FIG. 2, the clamp rod 3, the grip member 2, the piston member 42, and the annular pressure receiving member 71 are raised to the upper limit position. . Next, the workpiece W is carried in, the grip member 2 and the clamp rod 3 are inserted into the hole of the workpiece W, and the workpiece W is supported by the seating surface 18.

  Next, the hydraulic pressure is discharged from the unclamping oil chamber 47, and the elastic force of the downward compression spring 46 is applied to the piston member 42. Then, the annular pressure receiving member 71 receives the hydraulic pressure of the support oil chamber 72 and holds the upper limit position, and the grip member 2 also holds the upper limit position, but the piston member 42 is driven downward by the downward biasing force. Therefore, the clamp rod 3 moves downward relative to the grip member 2.

  As a result, the diameter of the grip claw portion 22 of the grip member 2 is increased by the taper shaft portion 31 of the clamp rod 3, and the grip member 2 is engaged with the inner peripheral surface of the hole of the workpiece W. Relative movement with the clamp rod 3 becomes impossible. From this state, as shown in FIG. 3, the hydraulic pressure is discharged from the support oil chamber 72 to release the hydraulic pressure of the support mechanism 7, and the piston member 42, the grip member 2, the clamp rod 3, and the annular pressure receiving member 71 are integrated. The workpiece W is driven downward by a small distance (for example, 0.2 mm), and the workpiece W is in a clamped state in which it is strongly pressed against the seating surface 18.

Here, as shown in FIG. 4, when the clamping state of the clamping device C is forcibly released, first, the clamp body 1 that drains the oil in the unclamping oil chamber 47 and the support oil chamber 72 is used as the base body member. 13 is removed from the mounting hole 13a, and the bottom wall member 61 is opened to the outside. Since the mounting hole 13a of the base main body member 13 is formed in a penetrating shape, the clamping state of the clamping device C can be forcibly released without removing the clamp main body 1 from the base main body member 13. .
Next, the plug member 66 of the bottom wall member 61 is removed, the tip end portion of the screw member 91 is inserted into the screw hole 64, and the screw member 91 is screwed into the screw hole 64. Then, when the operating portion 92 is rotated to drive the screw member 91 into the clamp main body 1, the tip end portion of the screw member 91 comes into contact with the lower end surface of the piston portion 43 (oil passage forming member 57).

  When the screw member 91 is further tightened and driven, the screw member 91 presses the piston portion 43 upward (unclamp side), and the clamp rod 3 and the annular pressure receiving member 71 are pushed up by the upper end portion of the piston member 42 and move upward. As a result, the grip member 2 is reduced in diameter, and the clamping state of the clamping device C can be released. Thereafter, when replacing the grip member 2, the upper main body member 11 is removed from the lower main body member 12, the four-piece grip member 2 is disassembled and removed, and replaced with a new grip member 2.

Next, the effect of the clamping device C of the present invention will be described.
The forced unclamping means 9 can forcibly press the piston portion 43 to the unclamping side via the screw member 91 without using the hydraulic pressure of the unclamping oil chamber 47, so that the clamp device C in the clamped state is compressed. The clamp can be released against the urging force of the spring 46. Therefore, since the grip member 2 can be easily removed from the clamp body 1 and replaced, the maintenance of the clamp device C can be easily performed.

  The forced unclamping means 9 includes a screw hole 64 that is formed in the bottom wall member 61 so as to communicate with the unclamping oil chamber 47 and that can be opened and closed via the plug member 66, and the bottom wall member 61 is opened to the outside. Thus, the screw member 91 is screwed into the screw hole 64 and the tip end portion of the screw member 91 is brought into contact with the piston portion 43 and pressed toward the unclamp side. The clamping device C can be unclamped by moving the portion 43 to the unclamping side.

  The support mechanism 7 includes an annular pressure receiving member 71 that supports the proximal end of the grip member 2 and a support oil chamber 72 that applies hydraulic pressure to the proximal end of the annular piston portion 73 of the annular pressure receiving member 71. By supporting the grip member 2 with the oil pressure of the diameter, the diameter can be surely expanded.

Next, the clamp apparatus CA of Example 2 is demonstrated based on FIGS. However, the same components as those in the first embodiment are denoted by the same reference numerals, description thereof is omitted, and different configurations are mainly described.
As shown in FIGS. 5 to 8, the clamp device CA includes a clamp main body 101, a grip member 102, a clamp rod 103, a driving means 104 that drives the clamp rod 103 to move back and forth, a support mechanism 106, a forced unlocking device. Clamping means 109 is provided. The clamp body 101 includes an upper body member 111 and a lower body member 112, and the clamp body 101 is assembled to the base body member 113.

  The upper main body member 111 is a member having a substantially square configuration in plan view. The upper body member 111 is fixed to the base body member 113 by four bolts 114 inserted into the four bolt holes 114. The lower main body member 112 is a cylindrical member that forms a cylinder hole 141, and the upper end portion of the lower main body member 112 is fitted into the concave portion 115 on the lower surface side of the upper main body member 111 and is fixed by four bolts 116. Yes. A cylindrical main body cylinder portion 120 protruding upward is provided at the center of the upper half of the clamp main body 101.

  As shown in FIGS. 5 to 8, the grip member 102 vertically penetrates the insertion hole 117 at the center portion of the upper end portion of the main body cylinder portion 120. Four arc-shaped seating surfaces 118 surrounding the grip member 102 are formed on the upper surface of the main body cylinder portion 120, and the workpiece W can be clamped in a state where the workpiece W is seated on the seating surface 118. . Four concave grooves 119 through which air blow of pressurized air flows are formed in a cross shape on the upper surface of the main body cylinder portion 120.

  The grip member 102 includes a rod insertion hole 121, a grip claw portion 122, and a proximal end flange portion 123, except that three-step teeth are formed on the outer peripheral surface of the grip claw portion 122. Since it is the same as that of Example 1, detailed description is abbreviate | omitted.

  A scraper 126 that closes the annular gap on the outer peripheral side of the grip member 102 is attached to the insertion hole 117 at the upper end of the main body cylinder portion 120. The scraper 126 has a function of preventing the intrusion of foreign matter and a function of centering so that the axis of the grip member 102 and the clamp rod 103 coincides with the axis of the clamp device CA in the unclamped state. It is. An O-ring 127 is attached to the lower part of the grip member 102 to bundle four divided bodies and bias them in the direction of diameter reduction.

  The proximal end cylindrical portion of the grip member 102 is accommodated in the circular recess 129 of the main body cylindrical portion 120, and a gap is formed on the outer peripheral side of the proximal end flange portion 123. The base end flange portion 123 of the grip member 102 is movably sandwiched between the upper wall portion of the circular recess 129 and the horizontal plate portion 172 of the support member 162 and supported by the support member 162. The grip member 102 can move up and down integrally with the support member 162 and the annular pressure receiving member 161, and is orthogonal to the axial center of the clamp device CA through the annular clearance of the outer periphery of the circular recess 129 and the elastic deformation of the scraper 126. It is mounted so that it can move horizontally.

  The clamp rod 103 is formed by integrally forming a tapered shaft portion 131, a small-diameter rod portion 132 connected to the lower end of the tapered shaft portion 131, and a T-shaped engaging portion 133 connected to the lower end of the small-diameter rod portion 132. Since the T-shaped engagement portion 133 is formed in place of the large-diameter rod portion 33 and the large-diameter flange portion 34 of the first embodiment, detailed description thereof is omitted. .

Next, the drive unit 104 will be described.
As shown in FIGS. 5 to 8, the driving means 104 is for driving the clamp rod 103 forward and backward with respect to the clamp body 101, and is clamp-driven by the elastic force of the compression spring 146 and clamped by the hydraulic pressure of the hydraulic cylinder. It is a release drive.

  The driving means 104 includes a vertically oriented cylinder hole 141, a piston member 142 mounted in the cylinder hole 141, an annular spring accommodating chamber 145 formed above the piston portion 143 of the piston member 142, and the spring Six compression springs 146 that are housed in the housing chamber 145 and strongly elastically bias the piston member 142 toward the clamp side, and hydraulic pressure that is formed below the piston member 142 and biases the piston portion 143 toward the unclamp side. An unclamping oil chamber 147 (an unclamping fluid chamber) is provided. The compression spring 146 for clamping is composed of a spring steel wire having a circular cross section.

  The piston member 142 includes a piston portion 143 and a rod portion 144 that extends upward from the piston portion 143 into the main body cylindrical portion 120. The outer peripheral portion of the piston portion 143 is oil-tightly sealed with a seal member 143a. The rod portion 144 includes a large diameter rod portion 150, a medium diameter rod portion 151 extending above the large diameter rod portion 150, a small diameter rod portion 152 extending above the medium diameter rod portion 151, and the small diameter rod portion 152. And a T-slot forming member 154 in which an inverted T-shaped T-slot 155 is formed is screwed to the screw shaft 153.

  The T-shaped engaging portion 133 of the clamp rod 103 is engaged with the T groove 155 of the T groove forming member 154 from the horizontal side. The outer diameter of the T-groove forming member 154 is slightly larger than the outer diameter of the small-diameter rod portion 152, and the lower end of the T-groove forming member 154 is locked by the upper end of a thin sleeve 166 described later of the annular pressure receiving member 161. A locked portion 156 is formed. A slight gap is formed between the T-shaped engaging portion 133 and the T-groove forming member 154. Therefore, the clamp rod 103 can move in the horizontal direction relative to the T groove forming member 154 by the amount of the gap.

  The spring accommodating chamber 145 is formed on the outer peripheral side of the large diameter rod portion 150 and the medium diameter rod portion 151. In this spring accommodating chamber 145, six compression springs 146 arranged at equal intervals in the circumferential direction are mounted in a compressed state to urge the piston portion 143 downward. The upper ends of the compression springs 146 are received in the six receiving holes 157 formed in the lower body member 112 and are received by the upper walls of the receiving holes 157, respectively. FIG. 6 shows an unclamped state. In this unclamped state, when the piston member 142 is at the upper limit position, the upper end portion 150a of the large-diameter rod portion 150 is locked by the locking portion 169 of the lower body member 112. The upper end portion 151 a of the medium diameter rod portion 151 is received by the lower end portion of the annular pressure receiving member 161. The spring accommodating chamber 145 is connected to a pressurized air supply source (not shown) via the air passages 158a to 158c, and when the clamping force is insufficient with the urging force of the compression spring 146, the spring accommodating chamber 145 is added to the spring accommodating chamber 145. Pressurized air can be supplied.

  The unclamping oil chamber 147 is formed of the lower main body member 112 and the base main body member 113 below the piston member 142. The unclamping oil chamber 147 is connected to a hydraulic pressure supply source (not shown) via an oil passage 159 formed in the base body member 113.

Next, the support mechanism 106 will be described.
As shown in FIGS. 6 to 8, the support mechanism 106 supports the grip member 102 with hydraulic pressure in order to increase the diameter of the grip member 102. The support mechanism 106 includes an annular pressure receiving member 161 movably fitted on the small-diameter rod portion 152 of the piston member 142, and a support member whose base end is supported by the annular pressure receiving member 161 and supports the base end of the grip member 102. 162 and a support oil chamber 163 (support fluid chamber) for applying hydraulic pressure to the proximal end of the annular piston portion 164 of the annular pressure receiving member 161.

  The annular pressure receiving member 161 includes an annular piston portion 164, a locking flange 165 at the upper end of the annular piston portion 164, and a thin sleeve 166 extending a predetermined length upward from the inner peripheral portion at the upper end of the annular piston portion 164. Has been. The annular piston portion 164 is slidably fitted to the small diameter rod portion 152 and slidably fitted to the cylindrical hole 167 of the lower main body member 112. The inner peripheral part of the annular piston part 164 is oil-tightly sealed with a seal member 164a, and the outer peripheral part is oil-tightly sealed with a seal member 164b.

  The locking collar portion 165 of the annular pressure receiving member 161 is mounted in an accommodation hole 168 formed by the upper body member 111 and the lower body member 112 so as to be vertically movable. The lower limit position of the annular pressure receiving member 161 is defined by locking the locking collar 165 with the lower end wall of the receiving hole 168, and the annular pressure receiving member by locking the locking flange 165 with the upper end wall of the receiving hole 168. The vertical position of 161 is defined.

  The support member 162 includes a thin sleeve 166, a thin cylindrical portion 171 fitted on the small diameter rod portion 152, and a horizontal plate portion 172 at the upper end of the thin cylindrical portion 171. The clamp rod 103 passes through the circular hole 173 of the horizontal plate portion 172, and the circular hole 173 is formed to have a size that can pass through the clamp rod 103. The horizontal plate portion 172 at the upper end of the support member 162 is in contact with and supported by the lower surface of the base end flange portion 123 of the grip member 102, and the lower end of the thin cylindrical portion 171 is in contact with and supported by the upper end of the annular pressure receiving member 161. The member 162 moves up and down integrally with the annular pressure receiving member 161.

  The lower end of the annular pressure receiving member 161 faces the support oil chamber 163 and receives the hydraulic pressure. The support oil chamber 163 is connected to the unclamping oil chamber 147 through the throttle oil passage 174 and the oil passage 175 of the rod portion 144. In the unclamped state, hydraulic pressure is supplied from the unclamping oil chamber 147, and the oil chamber of the support oil chamber 163 is discharged through the throttle oil passage 174 to a drain pressure over a predetermined minute time from the start of the clamping operation. The function of the throttle oil passage 174 is the same as that of the first embodiment.

  An operation confirmation mechanism 180 that detects a state in which the annular pressure receiving member 161 is at the upper limit position and the lower limit position is provided. The operation confirmation mechanism 180 includes an air ejection hole that is opened on the lower end wall of the accommodation hole 168 so as to face the locking collar 165, a valve member that can open and close the air ejection hole, and pressurized air in the air ejection hole. An air passage 181 for supplying air, and a pressure switch (not shown) for detecting the level of air pressure in the air passage 181. In addition to this, although not shown, a seating detection means using pressurized air, an air blowing means for air blowing the seating surface, and the like are also provided.

Next, the forced unclamping means 109 will be described.
As shown in FIG. 9, the forced unclamping means 109 is for forcibly releasing the clamp device CA. The forced unclamping means 109 includes a pair of engaging portions 191, a gate-shaped member 193 having a pair of legs 194 that can be engaged with the engaging portions 191, and a connecting beam portion 195 of the portal-shaped member 193. And a screw hole 196 that can be screwed into the screw member 197 and a screw member 197 that can be driven back and forth in the axial direction of the clamp rod 103 with respect to the clamp body 101.

  The pair of engaging portions 191 includes a pair of concave portions formed in a shallow groove shape on the outer peripheral portion of the clamp body 101. The gate-shaped member 193 includes a pair of leg portions 194 and a connecting beam portion 195 that connects the lower ends of the pair of leg portions 194 to each other, and the upper end portion of the pair of leg portions 194 (the connecting beam portion 195). A pair of claw portions 194a that can be engaged with the pair of engaging portions 191 are formed so as to protrude toward the clamping device CA side. The pair of leg portions 194 are connected to the connecting beam portions 195 and fixed to the lower ends of the pair of leg portions 194 so as to be close to each other and separated from each other. Therefore, the distance between the pair of leg portions 194 can be adjusted according to the size of the clamp body 101 of the clamp device CA. In this embodiment, the engaging portion 191 is formed so as to consist of a pair of recesses, but it is not necessary to be limited to this configuration, and it may be formed in an annular groove.

  The screw member 197 is screwed into a screw hole 196 formed in the center portion of the connecting beam portion 195, and the tip portion (upper end portion) is received by the lower end surface of the piston portion 143 of the piston member 142. An operation portion 198 capable of rotating the screw member 197 is provided at the base end portion (lower end portion) of the screw member 197. By the rotation of the operation unit 198, the screw member 197 is driven back and forth in the axial direction. Instead of providing the operation portion 198 at the base end portion of the screw member 197, a tool may be connected to the screw member 197 to rotate the screw member 197.

  Thus, the forced unclamping means 109 removes the clamp main body 101 from the base main body member 113, opens the outer peripheral portion of the clamp main body 101, the unclamping oil chamber 147 and the piston portion 143 to the outside, and the portal member 193. The unclamping oil chamber is engaged with the pair of leg portions 194 engaged with the pair of engagement portions 191 in a state where the tip ends of the pair of leg portions 194 are engaged with the pair of engagement portions 191. Without using the hydraulic pressure of 147, the screw member 197 is screwed into the screw hole 196 and the tip of the screw member 197 is brought into contact with the piston portion 143, and the piston portion 143 is forcibly forced through the screw member 197. It is comprised so that it can press to the unclamp side.

Next, the operation of the clamping device CA of the present invention will be described.
When the workpiece W is clamped by the clamp device CA, first, hydraulic pressure is supplied to the unclamping oil chamber 147. Then, the clamp rod 103, the grip member 102, the piston member 142, the annular pressure receiving member 161, and the support member 162 are raised against the urging force of the plurality of compression springs 146 in the spring accommodating chamber 145, as shown in FIG. To the upper limit. Next, the workpiece W is carried in, the grip member 102 and the clamp rod 103 are inserted into the holes of the workpiece W, and the workpiece W is supported by the seating surface.

  Next, the hydraulic pressure is discharged from the unclamping oil chamber 147, and the elastic force of the downward compression spring 146 is applied to the piston member 142. Then, the annular pressure receiving member 161 receives the hydraulic pressure of the support oil chamber 163 and holds the upper limit position, and the support member 162 and the grip member 102 also hold the upper limit position, but the piston member 142 is caused by the downward biasing force. Since it is driven downward, the clamp rod 103 moves downward relative to the grip member 102.

  As a result, the diameter of the grip claw portion 122 of the grip member 102 is increased by the taper shaft portion 131 of the clamp rod 103, and it is engaged with the inner peripheral surface of the hole of the workpiece W to be engaged (grip state). The member 102 cannot move relative to the clamp rod 103. From this state, as shown in FIG. 7, the hydraulic pressure of the support mechanism 106 is released due to the delay in discharging the hydraulic pressure from the support oil chamber 163, and the piston member 142, the grip member 102, the clamp rod 103, the annular pressure receiving member 161, The support member 162 is integrally driven by a small distance (for example, 0.2 mm) downward, and the workpiece W is in a clamped state in which the workpiece W is strongly pressed against the seating surface.

  In the full stroke state of the clamping device CA without setting the workpiece W, the downward biasing force of the compression spring 146 acts on the piston member 142, and as shown in FIG. 8, the piston member 142 and the annular pressure receiving member 161, the support member 162, the grip member 102, and the clamp rod 103 move to the lower limit position, the annular pressure receiving member 161 abuts on the lower body member 112, and the T-groove forming member 154 is received from below by the thin sleeve 166, The piston portion 164 contacts the lower main body member 112, and the grip claw portion 122 of the grip member 102 is driven by the taper shaft portion 131 of the clamp rod 103 to expand to the maximum extent radially outward.

  As shown in FIG. 8, when forcibly releasing the clamp state of the clamp device CA, first, the oil in the unclamping oil chamber 147 and the support oil chamber 163 is discharged and taken out, and the clamp body 101 is removed from the base body member. The bolt member fixed to 113 is removed, and the outer peripheral portion of the clamp body 101, the unclamping oil chamber 147, and the piston portion 143 are opened to the outside. Next, with the distal end portions of the pair of leg portions 194 of the gate-shaped member 193 engaged with the pair of engaging portions 191, the screw member 197 is inserted into the screw hole 196, and the screw member 197 is Screwed into the screw hole 196. Then, when the operation unit 198 is rotated and the screw member 197 is driven to be clamped toward the clamp body 101, the tip of the screw member 197 comes into contact with the lower end surface of the piston part 143. The pair of leg portions 194 may be engaged with the pair of engaging portions 191 in a state where the screw member 197 is screwed into the screw hole 196 from the beginning.

  Further, when the screw member 197 is tightened and driven, the screw member 197 presses the piston portion 143 upward (unclamp side), and the clamp rod 103 and the annular pressure receiving member 161 move upward. As a result, the grip member 102 is reduced in diameter, and the clamping state of the clamping device CA can be released. Thereafter, when replacing the grip member 102, the upper main body member 111 is removed from the lower main body member 112, the four-part grip member 102 is disassembled and removed, and replaced with a new grip member 102. In this embodiment, when the screw member 197 presses the piston portion 143 upward, the upper end portion 151a of the medium diameter rod portion 151 is configured to push up the annular pressure receiving member 161. The thin cylindrical portion 171 may be pushed up at the upper end of the T groove forming member 154 without pushing up.

Next, the effect of the clamping device CA of the present invention will be described.
The forced unclamping means 108 can forcibly press the piston portion 143 to the unclamping side via the screw member 197 without using the hydraulic pressure of the unclamping oil chamber 147, so that the clamp device CA in the clamped state is compressed. The clamp can be released against the biasing force of the spring 146. Therefore, since the grip member 102 can be easily removed from the clamp body 101 and replaced, the maintenance of the clamp device CA can be easily performed.

  The forced unclamping means 109 includes a pair of engaging portions 191 formed on the outer peripheral portion of the clamp main body 101, and a portal member 193 having a pair of leg portions 194 that can be engaged with the engaging portions 191. A screw hole 196 is formed in the connecting beam portion 195 of the gate-shaped member 193 and can be screwed into the screw member 197. The outer peripheral portion of the clamp body 101, the unclamping oil chamber 147, and the piston portion 143 are opened to the outside. In addition, the screw member 197 is screwed into the screw hole 196 and the tip end portion of the screw member 197 in a state where the tip end portions of the pair of leg portions 194 of the portal member 193 are engaged with the pair of engaging portions 191. Is made to abut against the piston part 143 and pressed toward the unclamping side, so that the piston part 143 is moved toward the unclamping side by the rotation of the screw member 197 and the clamping device CA is unclamped. Rukoto can.

  Since the engaging portion 191 is formed of an annular groove or a pair of concave portions, the engaging portion 191 can be easily formed on the outer peripheral portion of the clamp body 101, and this compulsory unlocking is performed with respect to the existing clamping device CA. The clamping means 109 can be easily applied.

  The support mechanism 106 includes an annular pressure receiving member 161 movably fitted on the rod portion of the piston member 142, and a support member 162 whose base end portion is supported by the annular pressure receiving member 161 and supports the proximal end of the grip member 102. Since the support oil chamber 163 for applying hydraulic pressure is provided at the base end of the annular piston portion 164 of the annular pressure receiving member 161, the diameter of the grip member 102 can be reliably increased by supporting the grip member 102 with the oil pressure of the support mechanism 106. .

Next, a clamp device CB according to a third embodiment will be described with reference to FIG. However, the same constituent elements as those in the second embodiment are denoted by the same reference numerals, description thereof is omitted, and different configurations are mainly described.
As shown in FIG. 10, the clamp device CB includes a clamp main body 101B, a grip member 102, a clamp rod 103, a driving means 104 for driving the clamp rod 103 back and forth, a support mechanism 106, and a forced unclamping means 209. And. The clamp body 101B includes an upper body member 111 and a lower body member 112B, and the clamp body 101B is assembled to the base body member 113B.

  The lower body member 112B of the clamp body 101B has the same configuration as the lower body member 112 except that the pair of engaging portions 191 of the lower body member 112 of the second embodiment is omitted. The base body member 113B is the same as the base body member 113 of the second embodiment except that the screw hole 210 connected to the unclamping oil chamber 147 is formed from the back surface side and the shape of the oil passage 159 is changed. It is a configuration.

Next, the forced unclamping means 209 will be described.
As shown in FIG. 10, the forced unclap means 209 is for forcibly releasing the clamp device CB. The forced unclamping means 209 clamps the clamp body 101B with a screw hole 210 formed in the base body member 113B in communication with the unclamping oil chamber 147 and closed by a removable plug member (not shown). And a screw member 211 that can be driven back and forth in the axial direction of the rod 103.

  In a state where the detachable plug member is removed from the base main body member 113B, the screw member 211 is inserted and screwed into the screw hole 210, and the distal end thereof is brought into contact with the piston member 143. An operation portion 212 that can rotate the screw member 211 is integrally provided at a base end portion of the screw member 211. The screw member 211 is driven back and forth in the axial direction of the clamp rod 103 by the rotation of the operation unit 212. Instead of providing the operation unit 212 at the base end portion of the screw member 211, a tool may be connected to the screw member 211 to rotate the screw member 211.

  When forcibly releasing the clamp state of the clamp device CB, first, the oil in the unclamping oil chamber 147 and the support oil chamber 163 is discharged. Next, the plug member of the base body member 113 </ b> B is removed, the distal end portion of the screw member 211 is inserted into the screw hole 210, and the screw member 211 is screwed into the screw hole 210. Then, when the operating portion 212 is rotated to drive the screw member 211 into the clamp body 1, the tip end portion of the screw member 211 comes into contact with the lower end surface of the piston portion 143.

  Further, when the screw member 211 is tightened and driven, the screw member 211 presses the piston portion 143 upward (unclamp side), and the clamp rod 103 and the annular pressure receiving member 161 move upward. As a result, the grip member 102 is moved. The diameter can be reduced, and the clamped state of the clamp device CB can be released. Thereafter, when exchanging the grip member 102, the upper main body member 111 is removed from the lower main body member 112B and the base main body member 113B, the four-piece grip member 2 is disassembled and removed, and the grip member 102 is replaced with a new one.

Next, a modified example in which the above embodiment is partially modified will be described.
[1] In the first to third embodiments, the connecting means for connecting the screw members 91, 197, 211 to the clamp body 1, 101 are the screw hole 64 of the bottom wall member 61, the screw hole 196 of the portal member 193, and the base portion. Although the screw hole 210 of the main body member 113B is provided, it is not particularly limited to these, and the screw member may be connected to the clamp main body using other connecting means.
[2] The overall configuration of the clamp devices C to CB of the first to third embodiments is merely an example, and other configurations can be used as long as they constitute a clamp device that is clamp driven by a compression spring and unclamped by hydraulic pressure. It may be configured.
[3] In the clamping devices C to CB of the first to third embodiments, the hydraulic pressure is used to drive the piston members 42 and 142 to be unclamped. Instead of 47 and 147, an unclamping fluid chamber may be provided, and the piston members 42 and 142 may be unclamped using fluid pressure such as pressurized air. Further, a configuration may be adopted in which a pressure fluid is put into the spring accommodating chamber 145 side and a clamping force is generated by using both the elastic force of the compression spring 146 and the fluid pressure of the pressure fluid.
[4] In addition, those skilled in the art can implement the present invention by adding various modifications without departing from the spirit of the present invention, and the present invention includes such modifications. is there.

  The present invention relates to a clamp device (so-called so-called gripping and clamping on the inner peripheral surface of a hole by expanding the grip claw portion of a grip member inserted into a hole of a workpiece for machining, with a clamp rod. , Hole clamp or expansion clamp).

C, CA, CB Clamp device W Workpiece 1, 101, 101B Clamp body 2, 102 Grip member 3, 103 Clamp rod 4, 104 Drive means 7, 106 Support mechanism 9, 109, 209 Forced unclamp means 41, 141 Cylinder Holes 42, 142 Piston members 43, 143 Piston portions 45, 145 Spring accommodating chambers 46, 146 Compression springs 47, 147 Unclamping oil chamber (unclamping fluid chamber)
61 Bottom wall member 64, 196, 210 Screw hole 66 Plug member 71, 161 Annular pressure receiving member 72, 163 Support oil chamber 73, 164 Annular piston part 91, 197, 211 Screw member 191 Engaging part 193 Portal member 194 Leg part 195 Connecting beam

Claims (6)

Clamp device having a clamp body, a grip member capable of gripping the inner peripheral surface of the hole of the workpiece, a clamp rod engaged with the grip member, and a drive means for driving the clamp rod forward and backward In
The driving means includes a piston member mounted in a cylinder hole of the clamp body, one or more compression springs that bias the piston member toward the clamp side, and a fluid pressure that biases the piston member toward the unclamp side. And an unclamping fluid chamber supplied with
A screw member that can be driven back and forth in the axial direction of the clamp rod with respect to the clamp body, and forcibly unclamping the piston member via the screw member without using the fluid pressure of the unclamping fluid chamber A clamping device comprising a forceful unclamping means that can be pressed to the side. The clamp body includes a bottom wall member that closes an end opposite to the piston member of the unclamping fluid chamber,
The forced unclamping means includes a screw hole formed in the bottom wall member in communication with the unclamping fluid chamber and closed by a detachable plug member, and the bottom wall member is opened to the outside. 2. The screw member according to claim 1, wherein the screw member is screwed into a screw hole, and a tip portion of the screw member is brought into contact with a piston portion of the piston member and pressed toward the unclamp side. Clamping device. The forced unclamping means includes a pair of engaging portions formed on an outer peripheral portion of the clamp body, a portal member having a pair of legs engageable with the engaging portions, and the portal member A screw hole formed in the connecting beam portion and capable of screwing the screw member,
The outer peripheral portion of the clamp body, the unclamping fluid chamber, and the piston portion of the piston member are opened to the outside, and the distal ends of the pair of leg portions of the portal member are engaged with the pair of engaging portions. 2. The device according to claim 1, wherein the screw member is screwed into the screw hole and pressed to the unclamping side with the tip of the screw member abutting against the piston portion. Clamping device.   The clamping device according to claim 3, wherein the engaging portion is formed of an annular groove or a pair of concave portions. A support mechanism for supporting the grip member with fluid pressure for expanding the grip member;
2. The support mechanism includes an annular pressure receiving member that supports a proximal end of the grip member, and a support fluid chamber that applies fluid pressure to a proximal end of an annular piston portion of the annular pressure receiving member. The clamp apparatus as described in. A support mechanism for supporting the grip member with fluid pressure for expanding the grip member;
The support mechanism includes an annular pressure receiving member movably fitted to the rod portion of the piston member, a support member having a base end supported by the annular pressure receiving member and supporting the proximal end of the grip member, and the annular The clamp device according to claim 1, further comprising a support fluid chamber for applying fluid pressure to a proximal end of the annular piston portion of the pressure receiving member.