Fastening device

Abstract

To provide a fastening device capable of performing an excellent fastening operation and exhibiting high responsiveness of its releasing operation without adopting an actuation mechanism using a hydraulic or pneumatic pressure fluid at all.SOLUTION: Coils 54a and 54b of a self-holding solenoid 40 are energized to move a piston member 30 connected through a connector 66 to a movable iron core 50 in an internal void space of a pin body 28 in an axial direction. A steel ball 32 protruding from the outer peripheral surface of the pin body 28 is engaged with the tapered engaging surface 18 of a fastening bush 10 by protruding / retreating the steel ball 32 from the outer peripheral surface of the pin body 28 by the piston member 30, thereby fastening the fastening bush 10 to a fastening pin 12. When the steel ball 32 retreats into the pin body 28, the engagement is released to release the fastening of the fastening bush 10 to the fastening pin 12.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a fastening device, and in particular to a clamping device or fastening device that can be suitably used to fasten together a fixed plate to which a specific workpiece, jig, device, etc. is fixed, and a supporting body such as a pedestal or base element that supports or holds such a fixed plate. [Background technology]

[0002] Conventionally, there have been various types of fastening devices for fastening two members, and a suitable fastening device is selected and used according to the shape and application of the members to be fastened. For example, various fastening devices have been used to fix a workpiece (object) during assembly or measurement, and to attach various tools and jigs in machine tools such as machining centers. Specifically, in machine tools such as machining centers, various jigs such as clamps and vices are generally used to hold a workpiece to be machined, and these jigs are often fixed to a jig plate in order to facilitate and speed up the changeover of the jigs, and the jig plate is fastened to a base element so that various jigs can be attached to the base element. It is well known that fastening devices such as those disclosed in Japanese Patent Application Publication No. 2001-225236 and Japanese Patent Application Publication No. 2005-188670 are used to fasten the jig plate as a fixed plate and the base element as a support to each other.

[0003] Such a fastening device has a fastening bush fixedly attached to either the fixed plate or the support, a fastening pin fixedly attached to the other of them, inserted in the axial direction into the fastening bush so as to be fitted, and a piston member movable in the axial direction is provided in the fastening pin, and when the piston member is moved in the opposing direction between the fixed plate and the support by the action of hydraulic pressure or pneumatic pressure, the steel ball arranged inside the fastening pin is pressed and moved in a direction perpendicular to the axial direction of the fastening pin, and is partially protruded from the outer circumferential surface of the fastening pin so as to be engaged with the fastening bush. In other words, when the fastening pin is inserted into the fastening bush, an engagement portion provided on the inner circumferential surface of the fastening bush is engaged with the protruding portion of the steel ball, and the fastening bush and the fastening pin are engaged with each other or abutted against each other, so that the relative movement of the fastening pin in the axial direction can be prevented when the fastening pin is inserted into the fastening bush.

[0004] Therefore, by using a fastening device having such a structure, with the fastening bush and fastening pin attached to the fixed plate and support body, respectively, the fastening pin can be simply inserted into the fastening bush and the piston member moved by hydraulic or pneumatic pressure, etc., thereby making it possible to easily and quickly fasten the fixed plate and support body together.

[0005] However, in order to perform the fastening operation between the fixed plate and the support using such a fastening device, a mechanism is required to move the piston member disposed in the fastening pin in its axial direction using a pressure fluid (power source) such as hydraulic or pneumatic pressure, but this requires that a drive mechanism using such pressure fluid be provided for the fastening pin, and in addition to providing a flow path for the pressure fluid for such a drive mechanism, a device for generating such pressure fluid must also be prepared separately, which creates inherent problems such as a complex structure for the fastening pin and high costs for the entire device. Moreover, the drive mechanism using such pressure fluid leaves room for improvement in terms of its responsiveness. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2001-225236 A [Patent Document 2] JP 2005-188670 A Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been made against the background of the above-mentioned circumstances, and an object of the present invention is to provide a fastening device which is excellent in responsiveness of fastening and releasing operations without employing any operating mechanism which uses pressurized fluid such as hydraulic or pneumatic pressure. Another object of the present invention is to provide a fastening device which has a simplified structure and good operability, which does not require the provision of a pressure fluid supply source and a supply path therefor. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention provides, as a first aspect thereof, (a) a fastening bushing that is attached in a fixed position to one of two members to be fastened, (b) a fastening pin having a cylindrical pin body portion with an inner space extending in the axial direction, which is attached in a fixed position to the other of the two members and fastens the two members by being inserted into and engaged with the fastening bushing, and (c) a fastening pin that is disposed within the pin body portion of the fastening pin so as to be movable in a direction perpendicular to the axial direction, and which is engaged with the fastening bushing by protruding from the outer circumferential surface of the pin body portion. the fastening device is characterized in that it is configured to include: (a) at least one movable member which is movable in the axial direction and disengages from the fastening bush by retracting into the pin body; (d) a piston member which is housed in the inner cavity provided in the pin body of the fastening pin and moved axially within the inner cavity to protrude and retract the at least one movable member; and (e) an operating means which has a solenoid which moves a movable core by passing current through a coil, and which operates the piston member by the movement of the movable core in the solenoid to move the piston member in the axial direction within the internal cavity of the pin body.

[0009] In addition, in a second preferred embodiment of the fastening device according to the present invention, the solenoid is a self-holding solenoid in which the movable core is moved axially by passing current through a coil, and the moved movable core is attracted by a permanent magnet to hold its moved position.

[0010] Furthermore, in an advantageous third aspect of the fastening device according to the present invention, the self-holding solenoid is a bistable solenoid in which the movable core, which is moved axially by passing current through the coil, is magnetized and held by the permanent magnet at both ends in the direction of movement.

[0011] Furthermore, in a fourth preferable embodiment of the fastening device according to the present invention, the self-holding solenoid has a two-coil operating structure in which two coils are arranged in parallel in the axial direction of the movable iron core, and currents in opposite directions are passed through the two coils, thereby enabling the movable iron core to be driven in both directions in the axial direction.

[0012] In addition, in another preferred fifth aspect of the fastening device according to the present invention, the piston member and the movable iron core of the solenoid are connected by a connecting means.

[0013] And in a sixth advantageous embodiment of the fastening device according to the present invention, the connecting means comprises a retaining space provided in the lower part of the piston member and an engaging head provided in the upper part of the movable core, which is fitted into the retaining space so as to form a gap movable perpendicular to the axis, thereby realizing the connection between the piston member and the movable core.

[0014] In addition, in the fastening device according to the present invention, as a seventh aspect, a configuration characterized in that an adjustment means is further provided that can adjust the connection position between the piston member and the movable iron core by the connecting means in the axial direction.

[0015] In addition, an eighth aspect of the fastening device according to the present invention is characterized in that the piston member and the movable iron core in the solenoid are integrally connected to each other and configured as a single member. Effect of the Invention

[0016] Thus, in the fastening device according to the present invention, instead of the conventional operating method in which the axial operation of the piston member arranged in the fastening pin is achieved by the supply and discharge of pressurized fluid, a solenoid is used and the operation is performed by a movable iron core that is moved by passing electricity through the coil. Therefore, there is no need for a supply source of pressurized fluid, and there is no need to provide the piston member with a supply and discharge path for pressurized fluid or an operating mechanism using pressurized fluid. Therefore, the structure of the piston member can be advantageously simplified, and it is possible to achieve a faster response and faster fastening operation than operation using pressurized fluid (oil and pneumatic pressure).

[0017] In particular, by using a self-holding solenoid as the solenoid that operates the piston member, the movable core, which is moved by passing current through the coil, is attracted to a permanent magnet at the end of its movement, thereby holding it in that position. This makes it possible to simplify the structure for holding the movable core in its moved position, and since current needs to be passed through the coil only when the movable core is moving, power consumption is reduced and energy savings can be achieved.

[0018] In the fastening device according to the present invention, when the movable iron core in the solenoid coil which moves the piston member is operated, the current to the solenoid can be turned on and off simply by operating a switch. This eliminates the need for complex sequence control as in the case of operating hydraulic and pneumatic equipment. In addition, the fastening device does not require skilled experience to be operated, and even an operator with relatively little experience in such operations can easily handle it. [Brief description of the drawings]

[0019] [Figure 1] 1 is a vertical sectional view showing an example of a fastening device according to the present invention, illustrating a non-fastened state of a fastening pin and a fastening bush. FIG. [Diagram 2]2A and 2B are explanatory diagrams showing the form of a fastening pin provided with a solenoid in the fastening device shown in FIG. 1, in which (a) is an explanatory front view, and (b) is an explanatory cross-sectional view taken along line AA in (a). [Diagram 3] 2A and 2B are enlarged partial explanatory views showing the connection form between the piston and the movable core in the fastening device shown in FIG. 1, where (a) is an enlarged explanatory front view, (b) is a BB cross-sectional explanatory view in (a), and (c) is a CC cross-sectional explanatory view in (a). [Figure 4] FIG. 2 is an explanatory oblique view showing a state in which a connector attached to the upper part of a movable core is inserted into the lower part of a piston in the fastening device shown in FIG. 1 to interconnect the piston and the movable core, where (a) shows the state before insertion and (b) shows the state after insertion. [Diagram 5] 2 is an explanatory vertical sectional view showing a state in which the fastening device shown in FIG. 1 is used, illustrating a state in which a fastening pin and a fastening bush are clamped. FIG. [Figure 6] 1 in another state of use, in which the fastening pin and the fastening bush are in an unclamped state. FIG. [Figure 7] FIG. 11 is an explanatory vertical sectional view showing another example of a fastening device according to the present invention, showing a different example of a connection form between a piston and a movable core. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] In order to clarify the present invention more specifically, a specific configuration of a fastening device according to the present invention will be described in detail below with reference to the drawings.

[0021] First, Fig. 1 shows an example of a fastening device (clamp device) having a structure according to the present invention and used to connect a base element as a support body that is attached to a table of a machine tool such as a machining center or serves as a base during assembly or measurement work, and a fixed plate to which various jigs, tools, devices, workpieces, etc. are attached. The fastening device is configured to have a fastening bush 10 and a fastening pin 12. The fastening bush 10 is attached to the upper fixed plate 14 of two members to be fastened, which are arranged opposite each other vertically, and the other member is a base element 16, and the fastening pin 12 is attached to the lower base element 16. Generally, a plurality of fastening devices each consisting of the fastening bush 10 and the fastening pin 12 are used, and are used by being arranged between the fixed plate 14 and the base element 16 at the four corners thereof, for example.

[0022] The fastening bush 10 constituting such a fastening device is a member having an inner diameter larger than the outer diameter of the fastening pin 12 (specifically, the pin body 28) by a predetermined dimension and having an approximately cylindrical shape as a whole, as in the conventional case. As is clear from the drawings, the fastening bush 10 has a stepped circumferential surface whose inner hole is reduced in diameter at the middle, and a tapered engagement surface 18 is formed at the stepped portion, while an outer flange portion 20 of a predetermined thickness is integrally formed at the lower part of the outer periphery. The fastening bush 10 is fitted into a recess 22 provided so as to open to the lower surface of the fixing plate 14, and is attached and fixed in position to the fixing plate 14 by screwing a plurality of fixing bolts 24 penetrating the outer flange portion 20 into screw holes provided in the fixing plate 14.

[0023] On the other hand, the fastening pin 12 constituting the fastening device together with the fastening bush 10, as is clear from the drawing, has a cylindrical shape having a stepped inner hole penetrating in the vertical direction (axial direction), and a thick-walled rectangular disk-shaped outer flange portion 26 is provided at its lower part. A cylindrical pin body portion 28, which rises concentrically from the center of the outer flange portion 26 and is inserted into the inner hole of the fastening bush 10, is integrally provided on the upper surface of the outer flange portion 26, and is fixed to the base element 16 at the rectangular corners of the outer flange portion 26 by using fixing bolts (not shown). More specifically, the stepped inner hole penetrating the fastening pin 12 is provided so as to penetrate the pin body portion 28 in the axial direction and further penetrate the center of the outer flange portion 26, and the upper part is a small-diameter inner hole, while the lower part is a large-diameter inner hole.

[0024] A piston member 30 is housed in the inner hole of the fastening pin 12 and is arranged so as to be capable of reciprocating in the axial direction. The piston member 30 has large-diameter portions at the upper and lower parts, a small-diameter portion at the axial middle part, and an outer diameter of the lower large-diameter portion larger than that of the upper large-diameter portion. The upper large-diameter portion of the piston member 30 has a tapered outer circumferential surface that decreases in diameter downward so that it can be positioned in the small-diameter inner hole of the pin main body 28, while the lower large-diameter portion is positioned in the large-diameter inner hole extending from the lower part of the pin main body 28 to the outer flange portion 26 so that it can be moved in the axial direction of the piston main body 28.

[0025] When this piston member 30 is caused to move axially back and forth within the inner hole extending from the pin body 28 to the outer flange 26 of the fastening pin 12, a plurality of steel balls 32 serving as movable members, which are arranged circumferentially around the pin body 28 in a structure similar to that of the conventional art, can be caused to move forward or backward in a direction perpendicular to the axial direction of the pin body 28. That is, as in the conventional case, the steel ball 32 is pushed out of the receiving hole formed to penetrate the cylindrical wall portion of the pin body 28 by the tapered outer circumferential surface of the large diameter portion at the upper part of the piston member 30, causing a part of it to protrude from the outer circumferential surface of the pin body 28. On the other hand, due to the presence of a small diameter portion which serves as a constriction provided in the axial middle portion of the piston member 30, when this small diameter portion moves to the arrangement position of the steel ball 32, the steel ball 32 is allowed to move radially inward, whereby the steel ball 32 is moved backward and the protrusion from the outer circumferential surface of the pin body 28 can be eliminated.

[0026] 1 and 2, the fastening pin 12 is provided with a self-retaining solenoid 40 that hangs down from the outer flange 26 as an operating means for axially moving the piston member 30 housed in the inner hole of the pin body 28. Specifically, an inverted L-shaped mounting bracket 42 is bolted to the outer flange 26, and the self-retaining solenoid 40 is fixed and held to the mounting bracket 42 by a number of bolts 44. As shown in FIG. 2(b), the solenoid 40 has a rectangular planar shape, and two U-shaped covers 46a, 46b are combined in a rectangular shape to cover the outer periphery of the solenoid 40 and are attached by bolts 47a, 47b, respectively, to protect the solenoid 40.

[0027] Here, as is clear from Fig. 1 and Fig. 2, the self-holding solenoid 40 has a structure in which a movable core 50, a permanent magnet 52 positioned around the movable core 50, and two coils 54a, 54b are housed in a box-shaped case 48. Specifically, the rod-shaped movable core 50 is located in the center of the case 48, and can be moved in the axial direction of the movable core 50 (vertical direction in Fig. 1) in a sleeve 58 together with a plunger 56 fixed to the outer periphery of the movable core 50. The vertical movement of the movable core 50 is restricted by the plunger 56 abutting against an upper base 60a attached to the ceiling of the case 48 and a lower base 60b attached to the bottom of the case 48, so that the moving end is defined, and the movable core 50 penetrates the upper base 60a and can be fitted into the central hole of the lower base 60b, so that the movable core 50 can move in the axial direction.

[0028] In addition, upper coil 54a and lower coil 54b are disposed so as to sandwich permanent magnet 52 from above and below, and when current is passed through coils 54a and 54b via electric wire 62, a magnetic force in the same direction is generated, and movable core 50 together with plunger 56 is moved to one side in the axial direction, and at the end of the movement, plunger 56 is attracted or attracted to the permanent magnet 52 and held in a fixed position. On the other hand, when current is passed in the opposite direction through electric wire 60, a magnetic force in the opposite direction is generated in two coils 54a and 54b, and movable core 50 together with plunger 56 is moved in the opposite direction in the axial direction to that described above, and at the end of the movement, plunger 56 is attracted or attracted to the permanent magnet 52 and held in a fixed position.

[0029] 1, an adjustment nut 64 and a connector 66 are screwed onto a threaded portion provided on the upper part of the movable core 50 of the solenoid 40, and the connector 66 is fitted into the lower part of the piston member 30 to connect it to the piston member 30. This allows the piston member 30 to move axially as the movable core 50 moves axially.

[0030] 3, the connector 66 is composed of a large-diameter head 66a and a small-diameter leg 66b, and a screw hole 66c is provided so as to pass through the center of the head 66a. The corresponding side of the head 66a is cut off to form two flat surfaces 60d, 60d that are parallel to each other.

[0031] Meanwhile, a U-shaped head insertion hole 68a and a leg insertion hole 68b, into which the head 66a and the leg 66b of the connector 66 can be inserted so as to be loosely fitted in the axis-perpendicular direction, are provided in the large diameter portion of the lower part of the piston member 30. That is, the width of the U-shaped opening of the head insertion hole 68a is set to be larger than the distance between the opposing flat surfaces 66d, 66d of the head 66a of the connector 66, and the width of the U-shaped opening of the leg insertion hole 68b is also set to be larger than the diameter of the leg 66b of the connector 66. The axial height (length) of the piston member 30 in the head insertion hole 68a is set so that the clearance between it and the head 66a of the connector 66 fitted or inserted therein is made as small as possible, thereby enabling the axial movement of the movable core 50 to be transmitted to the piston member 30 with as little rattling as possible.

[0032] 4(a) and 4(b), when the connector 66 is fitted into the head insertion hole 68a and the leg insertion hole 68b opening to the side of the large diameter portion of the lower part of the piston member 30 in a configuration in which the adjustment nut 64 and the connector 66 are screwed onto the threaded portion provided on the upper part of the movable core 50, a predetermined gap is formed between the outer peripheral surface of the head 66a of the connector 66 and the inner surface of the head insertion hole 68a, as shown in FIGS. 3(a) to 3(c), and a predetermined gap is also formed between the outer peripheral surface of the leg 66b and the inner surface of the leg insertion hole 68b. As a result, radial deviation between the piston member 30 and the movable core 50 is not transmitted from one side to the other, and damage due to misalignment or runout of the movable core 50, and ultimately damage to the solenoid 40, can be advantageously avoided.

[0033] In addition, the adjustment nut 64, which is screwed onto the upper screw portion of the movable core 50 prior to the connector 66, adjusts the vertical stroke position (movement position) of the piston member 30 connected via the connector 66 according to the amount of screwing. As described later, as the movable core 50 moves to its downward moving end, the piston member 30 is moved axially downward and the steel ball 32 is caused to protrude from the pin main body 28, so that the fastening bush 10 and the fastening pin 12 are reliably clamped. Meanwhile, when the movable core 50 moves to its upper moving end, the steel ball 32, which has been released from the pressure applied by the upper large diameter portion of the piston member 30 moved axially upward, is moved into the pin main body 28, so that the fastening pin 12 is released from the fastening bush 10 and an unclamped state can be reliably realized.

[0034] In a fastening device having such a structure, after the pin body 28 of the fastening pin 12 is inserted into the fastening bush 10 from the state shown in Fig. 1, electricity is passed through the coils 54a, 54b of the solenoid 40 via the electric wire 62 to generate a magnetic force as shown by the arrow in Fig. 5, which moves the movable core 50 downward in the axial direction and causes the steel ball 32 to protrude outward from the pin body at the upper large diameter part of the piston member 30, thereby realizing a clamped state between the fastening bush 10 and the fastening pin 12 as shown in Fig. 5. In the solenoid 40, the movable core 50 moved to the downward movement end is held at the movement end by the plunger 56 fixed thereto being attracted and fixed by the permanent magnet 52.

[0035] In order to release the fastening bush 10 and the fastening pin 12 from the clamped state shown in Fig. 5 to the unclamped state shown in Fig. 6, the current from the external power source supplied by the electric wire 62 to the two coils 54a, 54b is switched to supply a current in the opposite direction to the current supplied in the clamped state shown in Fig. 5, thereby generating a magnetic force for moving the movable core 50 axially upward as shown by the outline arrow in Fig. 6, so that the movable core 50 is moved to the upper moving end, and the piston member 30 is moved axially upward, whereby the steel ball 32 is released from the restraint by the upper large diameter part of the piston member 30 and can enter the small diameter part in the middle of the piston member 30. As a result, the steel ball 32 retreats into the pin main body 28, and the protrusion from the pin main body 28 is eliminated, and the fastening between the fastening bush 10 and the fastening pin 12 is released. The movable core 50, which has been moved to the upper end, has the plunger 56 fixed thereto attracted by the permanent magnet 52 and held in a fixed position, and in this state, the current to the coils 54a, 54b is cut off. Also, by moving the piston member 30, its upper end comes into contact with the bottom surface of the recess 22 of the fixed plate 14 to which the fastening bush 10 is attached, and by making it protrude further, the edge between the fastening bush 10 and the fastening pin 12 can be advantageously cut.

[0036] In this manner, in the fastening device (clamp device) configured as described above, the movable iron core 50 is moved in its axial direction, and the piston member 30 is moved in its axial direction, simply by passing current through the solenoid 40. The steel ball 32 is caused to protrude and retract in response to the axial movement of the piston member 30, thereby making it possible to fasten or release the fastening bush 10 and the fastening pin 12. As a result, a power source (pneumatic or hydraulic) as in conventional fastening devices (clamp devices) is not required, and therefore not only is there no need to provide a drive (operating) mechanism using such a power source, or even a source for generating the same, but there is also no need to provide flow paths for supplying and discharging such pneumatic or hydraulic pressure, which advantageously simplifies the structure and contributes advantageously to reducing manufacturing costs.

[0037] In addition, when the piston member 30 is operated by the movable core 50 using the solenoid 40, the movable core 50 is attracted or attracted by a permanent magnet at the end of its movement and held in a fixed position. Therefore, electricity is only supplied and power is only consumed when the movable core 50 moves, which not only advantageously provides energy savings, but also provides quicker response than hydraulic and pneumatic operation methods, making it possible to complete the operation in about 40 ms, for example.

[0038] In addition, since the solenoid 40 is used to operate the piston member 30, the operation of the solenoid 40 can be controlled by a switch alone, which has the advantage of eliminating the need for complex sequence control as in the past. In addition, it has the characteristic of being easy to use, even for workers with relatively little experience in handling electrical products.

[0039] In the above embodiment, the movable core 50 of the solenoid 40 and the piston member 30 are connected via the connector 66. However, as shown in FIG. 7, it is also possible to directly connect the movable core 50 and the piston member 30 without using the connector (66) and to integrate them into one component.

[0040] 7, the piston member 30 and the movable core 50 are directly connected by screwing the movable core 50 in the solenoid 40 at a threaded portion provided at the top of the solenoid 40 into a screw hole provided to open at the bottom end of the piston member 30, thereby realizing axial movement of the piston member 30 in response to the axial movement of the movable core 50. Note that, here too, an adjustment nut 64 is screwed into the upper threaded portion of the movable core 50, thereby further controlling the axial stroke range (movement range) of the piston member 30 screwed into the movable core 50, so that the steel ball 32 can reliably move forward and backward. Also, here, the fastening bush 10 is fixed to the fixing plate 14 by screwing a threaded portion provided on the outer periphery of the fastening bush 10 into a threaded hole in the fixing plate 14, while the fastening pin 12 is fixed to the base element 16 by screwing a threaded portion provided on the outer periphery of the pin body 28 into a threaded hole penetrating the base element 16. In addition, in the fastening device shown in Fig. 7, parts similar to those in the above-mentioned embodiment are given the same numbers and detailed explanations are omitted.

[0041] The specific configuration of the present invention has been described above in detail based on a representative embodiment of the fastening device according to the present invention. However, it should be understood that this is merely an example, and that the present invention is not limited in any way by the above description.

[0042] First of all, it goes without saying that the structure for fastening the fastening bush 10 and the fastening pin 12 using the moving member (steel ball 32) can be any of various known structures, in addition to the structure according to the illustrated embodiment.

[0043] For example, in the illustrated embodiment, the movable member is composed of a plurality of steel balls 32, but the structure of such a movable member is not limited in any way as long as it is configured so that it can be moved in a direction perpendicular to the opposing direction of the two members to be fastened and can be moved protruded / retracted (retracted) from the fastening pin, and therefore there is no problem if the movable member is composed of an appropriate roller member, plate material, block body, etc.

[0044] Furthermore, the number of such movable members does not necessarily have to be multiple, and it is possible to arrange only one of them as long as reliable clamping can be performed between the fastening bush 10 and the fastening pin 12.

[0045] Furthermore, in the illustrated embodiment, a plurality of steel balls 32 serving as movable members are disposed within through holes provided in the pin body portion 28 of the fastening pin 12, and are capable of moving protruding / retracting from such through holes, but it goes without saying that the disposition position and moving structure of such movable members are not particularly limited to the illustrated form.

[0046] In addition, as for the solenoid constituting the operating means for moving the piston member 30 housed in the inner space of the pin body 28 of the fastening pin 12 in its axial direction, a bistable type self-holding solenoid 40 as illustrated can be suitably used, but this is not limited to this, and various known solenoids can be used in which a movable iron core is moved by passing current through a coil, and the movement of the movable iron core moves the piston member in its axial direction.

[0047] In particular, in the present invention, a self-retaining solenoid is preferably used as the solenoid in which a movable core is moved axially by passing current through a coil, while the moved movable core is attracted or held by a permanent magnet to fix its moved position. However, there is no problem in using a solenoid having another known structure in which the movable core is held in a fixed position by magnetic force generated by a coil, without using a permanent magnet.

[0048] Furthermore, a self-holding solenoid is preferably a bistable solenoid in which the movable core, which is moved axially by passing current through a coil, is held in a fixed position by permanent magnets at both ends in the direction of movement. However, there is no problem if the solenoid is a monostable type solenoid in which the movable core is held in a fixed position by a permanent magnet at only one end of movement, while at the other end of movement, current is continued to be passed through the coil to hold it in place by the magnetic force generated by this, or the movable core is held in a fixed position by a mechanical or physical action.

[0049] Furthermore, as a self-holding solenoid, a one-coil type in which the movable core is actuated in one direction by passing current through the coil, or a two-coil type that can be actuated in both directions can be used. In the one-coil type, the movable core can be moved in one direction by passing current through the coil, but to move the movable core in the opposite direction, a method such as passing current in the opposite direction or using a return spring is adopted. In the two-coil type, two coils are arranged in parallel in the axial direction of the movable core, and currents are passed through the two coils independently in opposite directions, so that the movable core can be driven in both directions in the axial direction.

[0050] In addition, the illustrated embodiment shows a specific example of the application of the present invention to a fastening device used to fasten together a base element 16, which is attached to the table of a machine tool such as a machining center and serves as a support during assembly and measurement operations, and a fixed plate 14 to which jigs, tools, equipment, workpieces, etc. are fixed. However, it goes without saying that the present invention can also be advantageously applied to fastening devices used to fasten together two various components to be connected to each other, other than the combination of the base element 16 and the fixed plate 14.

[0051] In addition, although not listed one by one, the present invention can be embodied in various forms with changes, modifications, improvements, etc. based on the knowledge of those skilled in the art, and it goes without saying that all such embodiments fall within the scope of the present invention as long as they do not deviate from the spirit of the present invention. [Explanation of symbols]

[0052] 10 Fastening bush 12 Fastening pin 14 Fixing plate 16 Base element 18 Tapered engagement surface 20 Outer flange portion 22 Recess 24 Fixing bolt 26 Outer flange portion 28 Pin body portion 30 Piston member 32 Steel ball 40 Self-holding solenoid 42 Mounting bracket 44 Bolt 46a,46b Cover 47a,47b Bolt 48 Case 50 movable core 52 permanent magnet 54a, 54b Coil 56 Plunger 58 Sleeve 60a Upper Base 60b Lower base 62 Electric wire 64 Adjustment nut 66 Connector 66a Head 66b Legs 66c screw hole 60d flat surface 68a Head insertion hole 68b Leg insertion hole

Claims

1. A fastening bush is attached in a positionally fixed manner to one of the two members to be fastened; a fastening pin having a cylindrical pin body portion provided with an inner space extending in an axial direction, the fastening pin being attached in a positionally fixed manner to the other of the two members and being inserted into and engaged with the fastening bush to fasten the two members; at least one movable member disposed within a pin body of the fastening pin so as to be movable in a direction perpendicular to the axial direction thereof, and which engages with the fastening bush by protruding from an outer circumferential surface of the pin body, and which disengages from the fastening bush by retracting into the pin body; a piston member that is accommodated in the inner cavity provided in the pin body of the fastening pin and moved axially within the inner cavity to cause the at least one moving member to move forward and backward; an operating means having a solenoid for moving a movable core by energizing a coil, the piston member being actuated by the movement of the movable core in the solenoid, and moving the piston member in the axial direction within the internal space of the pin body; A fastening device comprising:

2. 2. The fastening device according to claim 1, wherein the solenoid is a self-holding solenoid in which the movable core is moved axially by passing current through a coil, and the moved movable core is attracted by a permanent magnet to hold its moved position.

3. 3. The fastening device according to claim 2, wherein the self-holding solenoid is a bistable solenoid in which the movable core, which is moved axially by passing current through the coil, is magnetically attracted to and held by the permanent magnets at both ends in the direction of movement.

4. 3. The fastening device according to claim 2, characterized in that the self-holding solenoid has a two-coil operating structure in which two coils are arranged in parallel in the axial direction of the movable core, and currents in opposite directions are passed through the two coils, thereby enabling the movable core to be driven in both directions in the axial direction.

5. 5. The fastening device according to claim 1, wherein the piston member and the movable iron core of the solenoid are connected by a connecting means.

6. 6. The fastening device according to claim 5, wherein the connecting means comprises a retaining cavity provided in a lower portion of the piston member, and an engaging head provided in an upper portion of the movable core, the engaging head being fitted into the retaining cavity so as to form a gap movable in a direction perpendicular to the axis, thereby realizing a connection between the piston member and the movable core.

7. 6. The fastening device according to claim 5, further comprising an adjustment means capable of adjusting a connection position between the piston member and the movable iron core by the connection means in the axial direction.

8. 5. The fastening device according to claim 1, wherein the piston member and the movable iron core of the solenoid are integrally connected to each other and constituted as a single member.

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