JPH0351085Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a workpiece holding device used for fixing a workpiece on a table of a machine tool.

[Prior art]

Conventionally, the above-mentioned workpiece holding device includes one disclosed in, for example, Japanese Utility Model Application Publication No. 58-70843. As shown in FIG. 3, a reference receiving frame 4 and a workpiece pushing frame 6 are fixedly mounted facing each other on the upper surface of a base plate 2 with a work placement space 8 therebetween. A workpiece receiving surface 10 is formed on the surface facing the workpiece presser frame 6, and a pressing means 12 is attached to the workpiece presser frame 6.
The output shaft 14 of this clamping means 12 is connected to the workpiece receiving surface 1
0, and the output shaft 14 is pressed by the clamping means 12.
The supported surface 20 of the workpiece holder 18 is brought into swingable spherical contact with the support surface 16 at the end of the output shaft 14 of the clamping means 12, and the workpiece holder A swing relief hole 22 is formed in the center of the bolt 26 , and a flange-like locked portion 24 is formed in the inner part of the swing relief hole 22 . Insert it loosely,
It is fixed to the center of the support surface 16 at the end of the output shaft 14, and an elastic body 34 is sandwiched between the head 32 of the bolt 26 and the locked part 24, and the elastic force of the elastic body 34 causes the workpiece to be held down. Press the tool 18 toward the output shaft 14 side and
6 and the supported surface 20, and the axis of the output shaft 14 and the swing relief hole 22 of the workpiece holder 18.
This feature is characterized in that the axes of the

Separately, Japanese Utility Model Application No. 55-179740 discloses a workpiece fastener using a spherical seat.
According to this, a stopper piece having a convex spherical surface and a mounting shaft is tiltably received on the workpiece contacting side of the clamp via a spherical receiver, and the mounting shaft is used as a clamp to penetrate through the spherical receiver. It is inserted through the formed hole and attached via a curved leaf spring, washer, and nut.

[Problem that the invention attempts to solve]

In the workpiece holding device described above, the elastic body 34 is sandwiched between the head 32 of the bolt 26 and the locked portion 24.
The work holding tool 18 is moved to the output shaft 14 by the elastic force of
However, in order to do so, the bolt 26 must be manually tightened, and the tightening force may vary depending on the person tightening it. In particular, when tightened firmly, the workpiece holder 18 becomes difficult to swing and does not follow the workpiece while holding the workpiece, causing damage to the workpiece. When the clamping means of this type of workpiece holding device is composed of a fluid pressure cylinder, it is desired that the clamping means be made as small as possible. However, when the length of the fluid pressure cylinder is shortened by, for example, reducing the clamping stroke in order to downsize, there is a problem in that this narrows the range in which workpieces with different sizes can be accommodated. That is, in the case of the one shown in FIG. 3, the structure is such that the workpieces having different dimensions can be handled only by the stroke of the fluid pressure cylinder. Therefore, miniaturization such as shortening the stroke cannot cope with differences in the dimensions of the workpiece. moreover,
In the model shown in Figure 3, the cylinder part is formed directly on the block fixed to the base plate, so if one block has a configuration in which many cylinder parts are formed, one of the hydraulic cylinders will fail. Even when the block was repaired, the entire block had to be replaced for repair, increasing the cost of spare parts and prolonging the interruption of machining operations for replacement, which caused problems in terms of repair.

In addition, in the structure of the other workpiece fastener mentioned above, since a curved leaf spring corresponding to the above-mentioned elastic body 34 is used, there is a problem similar to that described above due to the amount of tightening of the nut. At the same time, it is necessary for the leaf spring, washer, pad, or nut to slip between any of the abutting parts when the pad is tilted. There was a problem that smooth tilting could be hindered, and the machined part could easily be damaged. Note that, due to the shape of the curved leaf spring, chips are particularly likely to become narrowed.

[Means for solving problems]

The means for solving the above-mentioned problems according to this invention includes a reference receiver provided on the upper surface of the base, and a reference receiver provided on the upper surface of the base so as to face the reference receiver across the workpiece placement space. The workpiece holding part includes a fluid pressure cylinder with a piston rod protruding from one end as a pressing shaft, and a pressing member in swingable spherical contact with the protruding end of the pressing shaft. In the workpiece holding device, an insertion hole that opens toward the protruding end is formed in the pressing shaft along its length, a tension spring is accommodated in the insertion hole, and the opening is connected to the pressing member. A rear portion of the pressing member is locked to the inner part of the insertion hole via the tension spring so as to close the pressure member, a male screw portion is formed on the outer periphery of the fluid pressure cylinder, and a cylinder block is provided on the base plate. The cylinder block is characterized in that a female threaded portion corresponding to the male threaded portion is provided, and the fluid pressure cylinder is screwed into the cylinder block so that the forward and backward positions can be adjusted.

[Effect]

According to this means, the pressing member is maintained in spherical contact with the pressing shaft by the acting force of the tension spring. This acting force does not change depending on the person who installs it, and if the spring's acting force is selected appropriately, the pressing member can swing sufficiently.
Further, since the tension spring and its engaging portion are located within the insertion hole, and the insertion hole is closed by the pressing member, there is no chance of chips or the like getting in and interfering with the swinging of the pressing member.

Furthermore, since the fluid pressure cylinder moves forward and backward with respect to the cylinder block by rotating, even if a cylinder with a small clamping stroke is used, the range that can accommodate differences in the dimensions of the workpiece is widened to the extent that it can move forward and backward with a screw. . Further, since the hydraulic cylinder can be easily removed from the cylinder block, if an extra hydraulic cylinder is prepared, it can be easily replaced.

〔Example〕

The workpiece holding device of this embodiment has a base plate 40 formed into a plate shape, as shown in FIG. On one long side of the upper surface of the base plate 40, reference receiving portions 42 are provided at appropriate intervals along the long side. Further, on the other long side of the upper surface of the base plate 40, presser portions 44 are provided so as to face the reference receiving portions 42, respectively. The space between the reference receiving part 42 and the holding part 44 is a workpiece placement space. Furthermore, a reference receiving part 46 is provided further to the left of the reference receiving part 42 and the holding part 44 located on the leftmost side in FIG. 2 at an appropriate interval in the short side direction of the base plate 40. Similarly, a holding part 48 is provided further to the right of the reference receiving part 42 and holding part 44 located on the rightmost side so as to face the reference receiving part 46, respectively. The space between the reference receiving part 46 and the holding part 48 is also a workpiece placement space. Reference numeral 50 denotes a height adjustment section, which is provided between the reference receiving section 42 and the holding section 44 on the base plate 40, respectively. 52
is a groove having a T-shaped vertical cross section, and is provided on the upper surface of the base plate 40, and these are provided with reference receiving portions 42, 4.
6. Bolts (not shown) provided on the holding parts 44 and 48 and the height adjustment part 50 are engaged, and the positions of the reference receiving parts 42 and 46, the holding parts 44 and 48 and the height adjustment part 50 are adjusted. It is for adjustment.

The holding portion 44 has a base 54 as shown in FIG. At the left end of this base plate 54 in FIG.
is drilled. A cylinder block 56 is provided on the right end side of the upper surface of the base 54. Inside this block 56 is a cylinder tube 5.
8 are screwed together. Therefore, a female threaded portion 60 is cut into the inner peripheral surface of the cylinder block 56, and a male threaded portion 62 is cut into the outer peripheral surface of the cylinder tube 58. In addition, the female thread part 60
The cut portion is longer in distance than the cut portion of the male threaded portion 62, and the cylinder tube 58 can be moved forward and backward by a certain distance from the cylinder block 56.

A piston 64 is provided within the cylinder tube 58 so as to be able to move forward and backward, and with its tip protruding from the cylinder tube 58 . Also,
This piston 64 is pressed by a coil spring 66 provided around it toward a lid member 70 having an oil supply port 68 provided at the rear.

The piston 64 is provided with an insertion hole 72 that passes through the piston 64 in its length direction. A locking member 74 is fixed to the innermost part of the insertion hole 72 by a pin 76. This locking member 74 has a bifurcated portion 78 at its tip, and a pin 80 is provided so as to straddle the bifurcated portion 78 .

A concave spherical receiving portion 82 is provided at the tip of the piston 64.
is provided, and the convex spherical surface on the back side of the pressing member 84 formed in a bowl shape is in contact with this. That is, the receiving portion 82 and the pressing member 84 are in spherical contact to close the insertion hole 72 and are swingable. A bifurcated portion 86 is formed so as to enter into the insertion hole 72 from the back side of the pressing member 84, and a pin 88 is provided so as to straddle between the bifurcated portions. This pin 8
A coil spring 90 is provided in the insertion hole 72 so as to engage with the pin 80 of the locking member 74. The tensile force of the coil spring 90 maintains the spherical contact state of the pressing member 84 with the receiving portion 82 .

As is clear from FIG. 1, the cylinder tube 58, piston 64, etc. are provided on the cylinder block 56 so as to be inclined obliquely downward. This is to prevent the workpiece from floating.

The presser section 48 is also configured in the same manner as the presser section 44, so a detailed explanation will be omitted.

In such a workpiece holding device, the reference receiving part 4
2, 46, a workpiece is placed in the space surrounded by the holding parts 44, 48, pressure oil is supplied into the cylinder tube 58, the piston 64 is advanced, and the workpiece is referenced by the pressing member 84. Press toward the receiving portions 42 and 46 and hold.

〔effect〕

As described above, according to this invention, the pressing member is maintained in a state in which it is in spherical contact with the tip of the pressing shaft by the tension force of the spring. This acting force does not change depending on the person installing it, the pressing force of the pressing member against the pressing shaft is constant, and if an appropriate spring is selected, the pressing member can swing freely. Because the rocking process during the process of contacting and holding the workpiece is performed very smoothly,
It does not cause damage to the workpiece. Since the tension spring and its engaging portion are located within the insertion hole that is isolated from the outside world, the favorable swinging state is not disturbed by chips or the like.

Further, since the cylinder block and the fluid pressure cylinder (cylinder tube) are screwed together, the fluid pressure cylinder can be moved forward and backward and can be easily attached and detached. This widens the range that can accommodate differences in the dimensions of the workpiece by the amount of forward and backward movement, which is effective in downsizing in that the piston stroke of the fluid pressure cylinder can be shortened.
If the fluid pressure cylinders are standardized and prepared, in the case of a workpiece holding section that incorporates many fluid pressure cylinders into one cylinder block, the fluid pressure can be prepared in case of failure of some hydraulic cylinders. Since it can be repaired by replacing the cylinder, there is no need to replace the malfunctioning fluid pressure cylinder along with the cylinder block, as was the case in the past.Repairs are easy and can be completed in a short period of time, reducing the interruption of machining work. This produces the effect of increasing the temperature. Moreover, since the cylinder block itself is almost unlikely to fail, it is sufficient to stock only the fluid pressure cylinder as a spare part, and the cost for spare parts can be reduced.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional view of a presser part used in an embodiment of the workpiece holding device according to this invention, Fig. 2 is a partially omitted plan view of the same embodiment, and Fig. 3 is a partially omitted plan view of the conventional workpiece holding device. FIG. 40... Base board, 42, 46... Reference receiving part, 4
4, 48... Presser part, 56... Cylinder block, 58, 64, 70... Fluid pressure cylinder, 58
...Cylinder tube, 60...Female thread part, 62
...Male thread portion, 64...Press shaft, 72...Through hole, 84...Press member, 90...Tension spring.

Claims (1)

[Scope of utility model registration request] It has a reference receiving part provided on the upper surface of the base plate, and a workpiece holding part provided on the upper surface of the said base so as to face the reference receiving part across a workpiece placement space, and this workpiece holding part However, in a workpiece holding device including a fluid pressure cylinder with a piston rod protruding from one end as a pressing shaft, and a pressing member having a spherical surface in swingable contact with the protruding end of the pressing shaft, the length of the cylinder is within the pressing shaft. An insertion hole opened on the protruding end side along the direction is formed, a tension spring is accommodated in the insertion hole, and the back surface of the pressing member is closed by the pressing member so that the tension spring is closed. A male threaded portion is formed on the outer periphery of the fluid pressure cylinder, a cylinder block is provided on the base plate, and a female threaded portion corresponding to the male threaded portion is formed on this cylinder block. A workpiece holding device characterized in that the fluid pressure cylinder is screwed together so that the forward and backward positions of the workpiece holding device can be adjusted.