JPH0585296B2 - - Google Patents

Description

[Detailed Description of the Invention] <<Industrial Application Field>> The present invention is a hydraulic clamp that performs clamping operation by only one drive operation of one hydraulic cylinder, and which first uses a plurality of clamp claws arranged in an annular manner. The clamp claw is configured to be moved in parallel in the radial direction to switch from a non-clampable retracted position for replacing the fixed object to a clampable extended position, and then to drive the clamp claw in the axial direction for clamping. Regarding hydraulic clamps, this technology makes the structure for guiding the clamp claws parallel to the radial direction simple and strong.

[Prerequisite basic structure] This clamp claw radially retractable hydraulic clamp is
In order to make the structure of the hydraulic clamp compact and simple, the present inventor made it possible to perform parallel movement in the radial direction and drive in the axial direction of the clamp claw with only one driving operation of one hydraulic cylinder. The basic structure is as follows.

For example, Figure 1 to Figure 5, or Figure 16 and Figure 1.
As shown in Fig. 7, a plurality of clamp claws 8a arranged in an annular manner, a claw retraction spring 23, and an annular claw advancement taper cam 24 are attached to the hydraulic cylinder 7, and each of the plurality of clamp claws 8a arranged in an annular manner , is configured to be able to expand and contract between a clampable advanced position It is configured to be movable forward and backward between an unclamping position D and a clamping position C, and the clamping claw 8a is pressed toward the unclampable retracted position Y side by a claw retracting spring 23, whereas the clamping claw 8a is pressed toward the unclampable retracted position Y side by a claw advancing taper cam 24 to the clampable extended position. The allowable stroke L of the piston 12 of the hydraulic cylinder 7 is set to be greater than the sum of the lift M for clamp operation and the lift N for pushing out the clamp claw, so that the piston 12 can be pushed out from the top dead center to the clamp. In the clamp pawl extrusion operating state in which the section of the pawl extrusion lift N is driven toward the bottom dead center side, the clamp pawl 8a
is pushed out in the radial direction by the claw advancing taper cam 24 against the claw retracting spring 23 from the unclampable retracted position Y to the clampable extended position In the clamp operating state in which the section of the clamp operating lift M is driven toward the bottom dead center side, the clamp claw 8a is propelled from the unclamping position D to the clamping position C by the output section 31 that moves together with the piston 12. It is composed of

<<Prior Art>> In the above basic structure, it is necessary to prevent the clamp claw 8a from interfering with the fixed object B when replacing the fixed object B, and to prevent the fixed object B with the clamp claw 8a when clamping the fixed object B. For accurate extrusion, it is necessary to guide the clamping claw 8a in the radial direction. In order to achieve this parallel guidance, the present inventor first considered utilizing the guiding fit between the T-slot and the T-leg.

As shown in FIGS. 16 and 17, a guiding T-groove 90 is formed on the upper surface side of each clamp claw 8a so as to extend in the radial direction, and a T-block 91 is guided and slid into the T-groove 90. The T-block 91 is screwed and fixed to the lower surface of the output section 31 using screws 92.

<<Problems to be Solved by the Invention>> There are the following problems with the above-mentioned prior invention structure.

(b) The manufacturing cost of the entire hydraulic clamp is high.

The T-groove 90 and the T-block 91 have a complicated shape and must be formed by milling, which takes time and effort. Moreover, a plurality of T grooves 90
Since each T block 91 must be accurately positioned with the screw 92, the assembly work is also time-consuming. For this reason, hydraulic clamp 3
The overall production cost is high.

(b) When reducing the capacity of a hydraulic clamp, it cannot be made compact.

When reducing the capacity of the hydraulic clamp 3, the dimensions of the components of the hydraulic cylinder 7 are reduced, and the T-slot 90, T-block 91 and screw 9 are
It is also necessary to reduce the size of 2. Since these clamp pawl guide parts have a complicated shape, if the dimensions are less than a predetermined size, it becomes difficult to process the parts, making it impossible to downsize the hydraulic clamp.

(c) Poor clamping efficiency.

Since each T-slot 90 described above must be machined individually for each clamp claw 8a, when a plurality of clamp claws 8a are combined, errors in the dimensions of the T-slots 90 tend to occur, and the guide of the clamp claw 8a Accuracy is low. Therefore, in order to accurately guide the clamp claw 8a, it is necessary to slow down the operating speed of the hydraulic cylinder 7 to slow down the movement speed of the clamp claw 8a, resulting in poor clamping efficiency.

(d) The durability of the part that guides the clamp claw is low.

When switching the clamp claw 8a from the clampable advanced position X to the clampable non-clampable retracted position Y,
By lifting the clamp claw 8a through the T block 91 with the screw 92, the clamp claw 8a
is pulled away from the pawl advancing taper cam 24, but since the small diameter screw 92 bears this pulling force, the screw 92 is easily damaged and the durability of the part that guides the clamp pawl 8a is low.

The present invention solves all of the above-mentioned problems, reduces the manufacturing cost of a hydraulic clamp, and allows a small-capacity hydraulic clamp to be downsized.
The purpose is to improve the efficiency of clamping work and the durability of the part that guides the clamp claws.

<<Means for Solving the Problems>> In order to achieve the above object, the present invention is characterized in that, in the basic structure described above, the structure of the portion that guides the clamp claw 8a in the radial direction is configured as follows. There is.

For example, as shown in FIG. 1 to FIG. 5, or FIG. 6 to FIG. 12, or FIG. By forming the grooves 28 and guiding and fitting the expansion/contraction movement guide ring 29 over these expansion/contraction movement guide circumferential grooves 28 so as to be able to slide freely in the radial direction, the expansion/contraction movement guide ring 29 can be slidably fitted in the radial direction. 29 guides each clamp claw 8a in parallel from the unclampable retracted position Y to the clampable advanced position In the clamp pawl retraction operating state, the expansion/contraction movement guide ring 29 is configured to separate each clamp pawl 8a from the pawl advancing taper cam 24.

<<Operation>> In the hydraulic clamp 3 of the present invention, the clamp claw 8a is switched as shown in FIGS. 1a, b, and c, for example, as the clamping/unclamping operation is performed.

In the unclamped state shown in FIG. There is.

During clamp operation, each clamp claw 8a
is guided parallel to the radial direction along the periphery of the expansion/contraction movement ring 29 when changing for the first time from the unclampable retracted position Y in figure a to the clampable advanced position X in figure b, and is prevented from tilting at the unclamping position D. Prevented. Therefore, the clamp claw 8a is driven in a correct posture from the unclamping position D in figure b to the clamp position C in figure c, and uneven contact does not occur when it comes into contact with the object B to be fixed. Thereby, during clamping, the hydraulic pressure of the hydraulic cylinder 7 is transmitted almost evenly in the circumferential direction from the clamp claw 8a to the object B to be fixed.

On the other hand, in the clamp claw retracted state where the hydraulic clamp 3 switches from the state shown in Figure B to the state shown in Figure A, the expansion/contraction movement guiding ring 29 applies force in the direction of separating the clamp claw 8a from the claw advancing taper cam 24. The cam engagement between the two is smoothly released. This prevents uneven force from being applied to each clamp claw 8a from the claw advancing taper cam 24, and allows the clamp claws 8a to be guided accurately. As a result, even if the operating speed of the hydraulic cylinder 7 is increased, the guiding accuracy of the clamp claw 8a is not impaired, and the efficiency of the clamping work is increased.

The expansion/contraction movement guide circumferential groove 28 and the expansion/contraction movement guide ring 29 described above can be formed by turning, so machining is easy. Moreover, since the assembly to the hydraulic cylinder 7 is completed by simply fitting the circumferential groove 28 of each clamp claw 8a into the ring 29, the assembly operation is easy. In this way, the parts that guide the clamp claws 8a in the radial direction are easy to process and assemble, so the manufacturing cost of the entire hydraulic clamp 3 can be kept low.

In addition, the circumferential groove 28 and ring 29 have a simple shape and can be machined by turning, so that they can be easily manufactured even if the dimensions of the parts are small. As a result, when reducing the capacity of the hydraulic clamp 3, not only the components of the hydraulic cylinder 7 but also the
The clamp pawl guiding components such as the circumferential groove 28 and ring 29 can also be made smaller, and the hydraulic clamp 3 can be made smaller.

Moreover, in order to manufacture the clamp claw 8a for one hydraulic clamp, it is sufficient to first turn a cylindrical material and then divide it into a plurality of pieces. As a result, the clamp claws 8a for one machine can be processed at the same time and manufactured to the same dimensional accuracy, thereby increasing the guiding precision of the clamp claws 8a.

Since the expansion/contraction movement guiding ring 29 constitutes the guide portion of the expansion/contraction movement guiding circumferential groove 28 over the entire circumferential area, the guide area is large and the surface pressure during the clamp claw retraction operation is small. For this reason,
Damage to the ring 29 and the circumferential groove 28 in contact therewith is prevented, and the durability of the portion that guides the clamp claw 8a in the radial direction is improved.

In addition, FIG. 6 to FIG. 12 (refer to the second embodiment)
is a clamp rod 6 protruding from the fixed side member A.
The present invention is applied to a type in which the cylinder body 9 of the hydraulic cylinder 7 is attached to and detached from the hydraulic cylinder 7, and further functions as follows.

7a, b, and c show operation explanatory diagrams, and members having the same functions as those described above are given the same reference numerals.

In the unclamped state shown in FIG. 7 to a non-clampable retracted position Y away from the axis 7a.

Even if the axis 7a of the hydraulic cylinder 7 deviates from the axis of the clamp rod 6 when the cylinder body 9 is inserted into the clamp rod 6 from above,
When the inner circumferential surface of the clamp claw 8a partially contacts the outer circumferential surface of the rod neck 60 of the clamp rod 6 during the clamp claw pushing operation, the entire annularly arranged clamp claw 8a moves radially along the expansion/contraction movement guide ring 29. By sliding, the clamp claw 8
a is allowed to switch to the clampable advanced position X. For this reason, the axis 7a of the hydraulic cylinder 7
The allowable eccentricity between the shaft center and the axis of the clamp rod 6 can be increased, and the operation of attaching the cylinder body 9 to the clamp rod 6 does not require much effort. Furthermore, since the allowable eccentricity dimension is large, it is possible to simultaneously attach the cylinder body 9 to a large number of clamp rods 6 arranged in parallel, thereby increasing the clamping density.

Furthermore, FIGS. 13 to 15 (see the third embodiment) show the present invention applied to a type in which a flanged object B is fixed to a fixed side member A using a hydraulic clamp 3. Since the allowable eccentricity between the axis 7a of the hydraulic cylinder 7 and the axis of the object B is large, when the object B is replaced, the flange 82b of the object B is held against the clamp claw 8a. This is prevented and the replacement operation is easy.

<<Effects of the Invention>> Since the present invention is configured and operates as described above, it has the following effects.

(a) The production cost of hydraulic clamps is low.

The circumferential groove for guiding the expansion/contraction movement of the clamp claw and the ring for guiding the expansion/contraction movement of the clamp claw can be formed by turning, so machining is easy, and assembly to the hydraulic cylinder can be completed by simply fitting the above-mentioned circumferential groove to the ring. The assembly operation is also easy. In this way, since the portion that guides the clamp claw in the radial direction is easy to process and assemble, the manufacturing cost of the hydraulic clamp is low.

(b) A small-capacity hydraulic clamp can be made compact.

The above-mentioned circumferential groove and ring have a simple shape and only require turning, so they are easy to manufacture even if the parts are small in size. This results in
When reducing the capacity of the hydraulic clamp, not only the components of the hydraulic cylinder but also the components for guiding the clamp claws can be made smaller, and the entire hydraulic clamp can be made smaller.

(c) Efficiency of clamping work is improved.

Since the clamp claws for one hydraulic clamp are machined at the same time and manufactured with the same dimensional accuracy, the guidance precision of the clamp claws is high. Moreover, since it is possible to prevent irregular forces from being applied to the clamp pawl from the taper cam during the clamp pawl retraction operation, the guiding accuracy of the clamp pawl can be maintained at a good level. Since the guiding precision of the clamp pawl is thus high, the clamp pawl can be accurately guided even if the operating speed of the hydraulic cylinder is increased, and the efficiency of clamping work can be improved.

(d) The durability of the part that guides the clamp claw is improved.

The expansion/contraction movement guide ring has a large guide area and requires only a small surface pressure when the clamp claw is retracted, which prevents damage to the ring and the circumferential groove in contact with it, and guides the clamp claw in the radial direction. The durability of the part is improved.

(e) The present invention may be applied to a type in which the cylinder body is attached to and removed from the clamp rod (see Figures 6 to 12), or a type in which a flanged object is fixed to the cylinder body (see Figures 6 to 12). 13 to 15), it is possible to increase the allowable eccentricity between the axis of the hydraulic lift and the axis of the clamp rod or the flanged object. Therefore, it does not take much time to attach the cylinder body or the object to be fixed.

"Example" Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) FIGS. 1 to 5 show a first embodiment.
FIG. 1 is an explanatory view of the operation, and FIG. 2 is a longitudinal cross-sectional view showing how the hydraulic clamp is used.

In FIG. 2, the fixed base 1 which is the fixed side member A
A workpiece 2, which is an object to be fixed B, can be fixed to the upper surface of the workpiece 2 via a hydraulic clamp 3. The hydraulic clamp 3 is constructed by fixing a hydraulic cylinder 7 to the lower surface of the fixing base 1 with a plurality of bolts 5, and interlockingly connecting a clamping tool 8 to the upper side of the hydraulic cylinder 7. The clamp tool 8 consists of three clamp claws 8a, 8a, 8a arranged in an annular shape when viewed from above (see FIGS. 3 and 4). By pressing down each clamp claw 8a with the hydraulic pressure of the hydraulic cylinder 7, the workpiece 2 is pressed and fixed to the fixing table 1.

The above-mentioned hydraulic cylinder 7 is configured as a single acting spring return type. That is, the piston 12 is inserted into the lower part of the cylinder body 9 in a vertical and oil-tight slidable manner, a clamp hydraulic oil chamber 14 is formed above the piston 12, and a spring chamber 15 is formed below the piston 12. The clamp hydraulic oil chamber 14 is communicated with a hydraulic power source (not shown) via an oil supply/drain hole 17. On the other hand, spring chamber 1
A piston return spring 18 made of a compression coil spring is installed inside the piston 5 . A piston rod 20 is provided on the axis 7a of the hydraulic cylinder 7 to protrude upward from the upper surface of the piston 12. This passes through the upper end wall 9a of the cylinder body 9 in an oil-tight and slidable manner, and also passes through the insertion hole 1a of the fixing base 1 and the insertion hole 2a of the workpiece 2 so as to be vertically movable.

The clamp pawl 8a, a pawl retracting spring 23, and a pawl advancing taper cam 24 are provided on the rod upper portion 21 of the piston rod 20. The lower part 26 of each of the plurality of clamp claws 8a arranged in an annular manner is pressed by the claw retraction spring 23 toward the non-clampable retraction position Y, which is a smaller distance from the plurality of hydraulic cylinders 7a. On the other hand, the same axis center 7a
The claw can be pushed out to the clampable advancing position X side with a large distance from the clamping position X by the claw advancing taper cam 24 (see FIG. 1). At the clampable advance position X, the hydraulic cylinder 7 can be moved forward and backward along the axis 7a between an unclamping position D (see Fig. 1b) and a clamping position C (see Fig. 1c). be done.

First, the clamp claw 8a and the claw retraction spring 2
3 will be explained based mainly on FIGS. 3 to 5.

Each clamp claw 8a can expand and contract in the radial direction of the piston rod 20. That is, each of the annularly arranged clamp claws 8a has an expansion/contraction movement guide circumferential groove 28 formed at a mid-height part on the inner circumferential side. On the other hand, an expansion/contraction movement guide ring 29 is fitted onto the rod upper part 21 of the piston rod 20, and a circumferential expansion/contraction movement guide groove 28 is slidably guided and fitted into this expansion/contraction movement guide ring 29. Further, means is provided for guiding the clamp claws 8a evenly in a straight line in the radial direction of the piston rod 20. That is, the rod upper part 2
A rod output portion 31 is provided by expanding the diameter of the rod output portion 1, and a plurality of guide grooves 33 extending in the radial direction are formed on the lower surface side of the rod output portion 31. Further, a guide pin 34 is provided protruding from the upper surface of each clamp claw 8a,
A guide pin 34 is guided and fitted into the guide groove 33 . Thereby, the clamp claw 8a is guided straightly relative to the piston rod 20 only in the radial direction. A spring receiving groove 36 is formed in the peripheral wall of each of the clamp claws 8a, and the claw retracting spring 23 is mounted across these spring receiving grooves 3. This claw retraction spring 23 is composed of a spiral plate spring, as shown in FIG.

Next, regarding the claw retraction taper cam 24,
The explanation will be mainly based on FIG.

From the upper end wall 9a of the cylinder body 9 to the guide tube 39
is projected upward. A cylindrical pawl advance/retreat taper cam 24 is inserted into the annular space between the inner peripheral surface of the guide cylinder 39 and the outer peripheral surface of the piston rod 20 so as to be vertically movable. This claw retraction taper cam 24
is pressed upward by a pressing spring 40, and is prevented from moving upward by more than a predetermined amount by a stopper inner flange 41 of the guide cylinder 39. Then, due to the elastic force of the pressing spring 40, the tapered cam surface 43 formed on the upper part of the pawl advance/retreat taper cam 24 comes into contact with the cam engagement surface 44 of each clamp pawl 8a. .

Then, by supplying pressure oil from the oil supply/discharge hole 17 to the clamp hydraulic oil chamber 14 in the cylinder body 9, the piston 12 is pushed down by the oil pressure against the elastic force of the piston return spring 18. Accordingly, the output portion 31 formed on the upper portion 21 of the piston rod 20 pushes down the clamp tool 8. As a result, the hydraulic clamp 3 is switched from the unclamped state shown in FIG. 1a, through the switching transient state shown in FIG. 1b, to the clamped state shown in FIG. 1c.

The permissible vertical stroke L of the piston 12 within the cylinder body 9 is set to be greater than the sum of the lift M for clamp operation and the lift N for pushing out the clamp claw. In the clamp pawl extrusion operating state during the transition from figure a to figure b, the piston 12 is driven from the top dead center toward the bottom dead center through the section of the lift N for pushing out the clamp pawl. Along with this, the clamp claw 8a is pushed outward in the radial direction along the expansion/contraction movement guiding ring 29 against the pawl retraction spring 23 by the pawl advancing taper cam 24, and this expansion/contraction movement guiding ring 29 and the guide groove 33 and guide pin 34
is guided almost evenly in parallel in the radial direction through the
can be switched to.

Furthermore, in the clamp operating state during switching from Figure B to Figure C, the piston 12 moves down the section of the clamp operating lift M below the clamp claw pushing lift N, and the output provided at the upper part 21 of the rod is lowered. The portion 31 pushes down the clamp claw 8a.
Along with this, the clamp claw 8a switches from the unclamp position D to the clamp position C, and presses and fixes the workpiece 2.

On the other hand, when switching from the clamped state shown in Fig. c to the unclamped state shown in Fig. B through the switching transient state shown in Fig. B, the pressure oil is discharged from the clamp hydraulic oil chamber 14 and the elastic force of the piston return spring 18 is applied. This is done by returning the piston 12 to the top dead center.

In the unclamping operation state that changes from figure c to figure b, the piston 12 is driven in the section of the lift M for clamp operation from the bottom dead center side to the top dead center side,
The clamp pawl 8a is raised by the expansion/contraction movement guide ring 29 which rises together with the piston rod 20. As a result, the clamp claw 8a is switched from the clamp position C to the unclamp position D. In this case, as the clamp claw 8a rises, the claw advancing taper cam 24 is raised by the pressure spring 40. In the state shown in Fig. b, the pawl advancing taper cam 24 is received by the stopper flange 41 of the guide cylinder 39, and is prevented from rising any further.

In addition, in the clamp pawl retracting operating state that changes from figure b to figure a, the piston 12 is driven from the bottom dead center side to the top dead center side in the section of the lift N for pushing out the clamp pawl. Along with the rise of the piston rod 20, the expansion/contraction movement guiding ring 29 rises, and each clamp claw 8 is moved through this expansion/contraction movement guiding ring 29.
a is separated from the pawl advancing taper cam 24, and the clamp pawl 8a is switched from the clampable advanced position X to the unclampable retracted position Y by the elastic force of the pawl retracting spring 23.

FIGS. 6 to 15 show other embodiments, and explanations will be given of configurations different from the first embodiment. Note that members that perform the same functions are given the same reference numerals as in the first embodiment.

(Second Embodiment) FIGS. 6 to 12 show a second embodiment, in which FIG. 6 shows the usage state of the hydraulic clamp, and FIG. 7 is an explanatory diagram of the operation.

In FIG. 6, the fixed base 1 which is the fixed side member A
A mold 52, which is an object to be fixed B, is fixed to the upper surface of the machine using a hydraulic clamp 3. The hydraulic clamp 3 consists of a hydraulically driven nut 4 and a clamp rod 6. A hydraulic cylinder 7 is provided in the lower part of the hydraulically driven nut 4. The clamp rod 6 vertically passes through a fastening hole 53 of the mold 52, and its leg portion 6a is fixed to the fixing base 1 with screws. During clamping work, an operator first grasps the hydraulically driven nut 4 by hand and inserts it into the clamp rod 6 from above, and then applies a lifting force to the clamp rod 6 using the hydraulic pressure of the hydraulic cylinder 7. As a result, the mold 2 is placed against the fixed base 1.
is pressed and fixed with a hydraulically driven nut 4.

The clamp rod 6 has a rod driven portion 61 formed on the upper side of a rod neck portion 60 that is inserted into the cylinder body 9. The external dimensions of the rod driven portion 61 are larger than those of the rod neck portion 60.

Further, the hydraulically driven nut 4 is constructed as follows. A cover plate 10 is screwed and fixed to the upper part of the cylinder body 9, a piston 12 is inserted into the lower part of the cylinder body 9, and a guide rod 13 is provided protruding from the lower surface of the piston 12. piston 1
A rod insertion hole 54 extends between the rod 2 and the guide rod 13.
is penetrated in the vertical direction. The piston 12
A clamp hydraulic oil chamber 14 is formed below the piston 12, and a spring chamber 15 is formed above the piston 12. The clamp hydraulic oil chamber 14 has an oil supply/drainage path 56 and a connection cap 5.
7. Connected to a hydraulic power source (not shown) via a flexible hydraulic hose 58. A piston return spring 18 is installed within the spring chamber 15.

A clamping tool 8, a pawl retraction spring 23, and a pawl advancing taper cam 24 are provided above the piston 12.

The clamp tool 8 has three clamp claws 8a, 8.
A rod insertion passage 62 extending vertically is formed in the inner peripheral surface of the rod insertion passage 62, and each clamp pawl 8a is configured to expand and contract in the radial direction of the rod insertion passage 62. That is, a disk-shaped expansion/contraction movement guide ring 29 is placed on the periphery of the upper end surface of the piston 12 . Further, an annular spring receiving plate 64 is received at a mid-height part of the cover plate 10, a piston return spring 18 is installed between the spring receiving plate 64 and an expansion/contraction movement guide ring 29, and the ring 29 is attached to the piston 12.
It is designed to move along with the vertical movement of the robot. Furthermore, an expansion/contraction movement guiding circumferential groove 28 is formed at the lower part of the outer circumference of each clamp claw 8a, and this circumferential groove 28 is fitted into the inner circumferential edge of the ring 29 so as to be slidable in the radial direction.

The claw retraction spring 23 described above is constructed as follows. Spring insertion holes 66, 66 extending in the tangential direction are formed facing each other in the clamp claws 8a, 8a adjacent to each other, and a guide pin 67 is inserted into the spring insertion holes 66, 66. This guide pin 67
Spring seat 68 formed by enlarging the axial center portion of
An opening spring 70 made of a compression coil spring is installed between the spring insertion hole 66 and the bottom wall of each spring insertion hole 66. Claw retraction spring 2 of these plurality of opening springs 70
3 are made up.

Further, the pawl advancing taper cam 24 is formed in a cylindrical shape, and a cam surface 43 is formed by an inner circumferential surface that increases in diameter as it goes downward. A flange portion 72 protrudes radially outward from the upper part of the peripheral wall of the taper cam 24, and this flange portion 72 is connected to the spring receiving plate 64.
is placed on the top surface of the Further, a pressure spring 40 is installed between the cylindrical spring receiver 73 placed on the upper surface of the taper cam 24 and the upper wall of the cover plate 10. The elastic force of this pressing spring 40 is set to be weaker than the elastic force of the piston return spring 18.

The hydraulic clamp configured as described above operates as shown in FIG.

FIG. 7a shows the unclamped state. Pressure oil is discharged from the clamp hydraulic oil chamber 14 and the piston 12 is lowered by the spring force of the piston return spring 18. As a result, each clamp pawl 8a expands in diameter along the ring 29 by the opening force of the pawl retraction spring 23, and the transmission tool 27 is switched to the retracted position Y where clamping is not possible (Figs. 9 and 10). reference).
In this unclamped state, the rod insertion passage 62 is opened and the diameter of the inner circumferential surface of the clamp tool 8 becomes larger than the outer diameter of the rod driven part 61. It can be inserted and removed freely.

FIG. 7b shows a switching transient. By supplying pressure oil to the clamp hydraulic oil chamber 14,
Piston 12 is driven upward. As the piston 12 moves up the section of the lift N for pushing out the clamp claws, the outer peripheral surface of each clamp claw 8a moves toward the taper cam 2.
4 is pressed inward by the cam surface 43 of the opening spring 7.
0 along the ring 29 to the clampable advance position X (Fig. 11 and 1).
(See Figure 2). As a result, the rod insertion passage 62 is closed, and the upper surface of the clamp claw 8a is inserted into the rod passive part 6.
It is switched to the unclamping position D, which faces the lower surface of 1 at a predetermined distance.

Fig. 7c shows the clamped state, and the clamp claw 8
a has been switched to clamp position C. As the piston 12 is driven upward in the section of the clamp operation lift M, the clamp claw 8a is moved against the pressure spring 4.
The upper end surface of the clamp claw 8a comes into contact with the lower surface of the rod driven portion 61. As a result, the hydraulic pressure pushing up force of the piston 12 is transmitted to the rod driven portion 61 via the clamp claw 8a, and the clamp rod 6 is clamped upward to obtain a clamped state.

(Third Embodiment) FIGS. 13 to 15 show a third embodiment.

In Fig. 13, fixed side member A of the injection molding machine
A cylinder head 82, which is a side object to be fixed with a flange, is removably fixed to the right side of the screw cylinder 81 with a hydraulic clamp 3, and the nozzle of the cylinder head 82 is fixed with a screw 83 inserted into the screw cylinder 81. Molten resin is injected from 82a. The hydraulic clamp 3 holds the cylinder body 9 of the hydraulic cylinder 7 with a plurality of fixing bolts 8.
5 is fixed to the right end surface of the screw cylinder 81. Then, by hydraulically driving the clamp claw 8a with the hydraulic pressure of the hydraulic cylinder 7, the outer flange 82b of the cylinder head 82 is moved into the screw cylinder 8.
It is designed to be hydraulically fixed at 1.

The hydraulic cylinder 7 has been modified from that of the second embodiment as follows.

That is, the clamp hydraulic oil chamber 14, the piston 12, and the clamp tool 8 are provided in this order between the right end wall 9b and the left end wall 9c of the cylinder body 9. The clamp tool 8 includes six clamp claws 8a arranged in an annular shape when viewed from the right side. Further, the claw retraction spring 23 is composed of a plurality of opening springs provided corresponding to the clamp claws 8a.

The hydraulic clamp 3 operates as follows.

In the clamped state shown in FIG.
2 is driven toward the left end wall 9c, the clamp claw 8a performs a clamping operation, and the outer flange 82b of the cylinder head 82 is pressed and fixed between the clamp claw 8a and the screw cylinder 81.

In the unclamped state, the piston 12 retreats toward the right end wall 9b of the cylinder body 9, and the clamp claw 8a is switched to the unclampable retracted position Y by the claw retracting spring 23 (see FIG. 14). In the switching transient state, the piston 12 is driven toward the left end wall 9c side of the cylinder body 9 by the lift for clamp tool claw extension, and the clamp claw 8a is switched to the clampable advance position X by the claw advance taper cam 24 (15th
(see figure). By further driving the piston 12 toward the left end wall 9c, the clamped state shown in FIG. 13 is obtained.

When installing the cylinder head 82, the first
In the state shown in FIG. 4, the cylinder head 82 is inserted into the cylinder body 9 and set on the fastening surface of the screw cylinder 81. When the hydraulic cylinder 7 is hydraulically driven, the clamp claw 8 is moved in conjunction with the movement of the piston 12.
a is automatically switched from the unclampable retracted position Y to the clampable advanced position X to perform the clamping operation.

Furthermore, when the cylinder head 82 is removed, the extrusion cylinder 7 is returned to its original position, so that the clamp claw 8a is operated in the opposite manner to the above.
At this time, the clamp claw 8a is moved by the claw retraction spring 23.
It is retracted to the unclampable retracted position Y. Thereby, the cylinder head 82 can be taken out from the cylinder body 9 without the outer flange portion 82b getting caught on each clamp claw 8a.

[Brief explanation of the drawing]

1 to 15 show embodiments of the present invention,
1 to 5 show a first embodiment. Fig. 1 is an explanatory diagram of the operation, Fig. 1 a shows the unclamped state, Fig. 1 b shows the switching transient state, Fig. 1 c shows the clamped state, and Fig. 2 shows the hydraulic clamp. FIG. 3 is a cross-sectional view taken along the - line arrow in FIG. 1 a, and FIG.
FIG. 5 is a sectional view taken along the line -- in FIG. b, and FIG. 5 is a developed perspective view of the clamp claw and the claw retraction spring. 6 to 12 show a second embodiment. Fig. 6 is a diagram corresponding to Fig. 2, Fig. 7 is an explanatory diagram of the operation, and Fig. 7 a, b, and c are respectively equivalent to Fig. 1 a, b, and c.
FIG. 8 is a view equivalent to FIG. 5, FIG. 9 is a view taken along the - line of FIG. 7a, and FIG.
11 is a sectional view taken along the line XI-XI of FIG. 7b, and FIG. 12 is a sectional view taken along the line XII-XII of FIG. 11. 13 to 15 show a third embodiment. 13 is a diagram equivalent to FIG. 2, FIG. 14 is a diagram equivalent to FIG. 9, and FIG. 15 is a diagram equivalent to FIG. 11. FIGS. 16 and 17 show examples of the prior invention. Figure 16 is a diagram equivalent to Figure 2, and Figure 17 is a diagram equivalent to Figure 1.
FIG. 6 is a sectional view taken along the - line in FIG. 6; 7... Hydraulic cylinder, 7a... Shaft center, 8a...
Clamp claw, 12... Piston, 23... Spring for claw retraction, 24... Taper cam for claw advancement, 28...
Circumferential groove for expansion/contraction movement guide, 29...Ring for expansion/contraction movement guide, 31...Output section, C...Clamp position, D
... Unclamping position, L ... Allowable stroke of piston 12, M ... Lift for clamp operation, N
...Lift for pushing out the clamp claw, X...Advanced position where clamping is possible, Y...Retracted position where clamping is not possible.

Claims (1)

[Claims] 1. A plurality of clamp claws 8a arranged in an annular manner, a claw retraction spring 23, and an annular claw advancement taper cam 24 are attached to the hydraulic cylinder 7, and each of the plurality of clamp claws 8a arranged in an annular manner , is configured to be able to expand and contract between a clampable advanced position It is configured to be movable forward and backward between an unclamping position D and a clamping position C, and the clamping claw 8a is pressed toward the unclampable retracted position Y side by a claw retracting spring 23, whereas the clamping claw 8a is pressed toward the unclampable retracted position Y side by a claw advancing taper cam 24 to the clampable extended position. The allowable stroke L of the piston 12 of the hydraulic cylinder 7 is set to be greater than the sum of the lift M for clamp operation and the lift N for pushing out the clamp claw, so that the piston 12 can be pushed out from the top dead center to the clamp. In the clamp pawl extrusion operating state in which the section of the pawl extrusion lift N is driven toward the bottom dead center side, the clamp pawl 8a
is pushed out in the radial direction by the claw advancing taper cam 24 against the claw retracting spring 23 from the unclampable retracted position Y to the clampable extended position In the clamp operating state in which the section of the clamp operating lift M is driven toward the bottom dead center side, the clamp claw 8a is propelled from the unclamping position D to the clamping position C by the output section 31 that moves together with the piston 12. In the clamp claw radially retractable hydraulic clamp configured as shown in FIG. By fitting the guide ring 29 so as to be slidable in the radial direction, the expansion/contraction movement guide ring 29 moves each clamp claw 8a from the unclampable retracted position Y to the clampable extended position in the clamp claw extrusion operating state. In the clamp claw retracting operating state in which the piston 12 moves the section of the lift N for pushing out the clamp claws from the bottom dead center side toward the top dead center side, the expansion/contraction movement guide ring 29 guides each clamp in parallel to X. Claw 8
A clamp pawl radially retractable hydraulic clamp characterized in that the clamp pawl radially retractable type hydraulic clamp is configured such that the clamp pawl a is separated from the pawl advancing taper cam 24.