JPS6116025Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a floating chuck for gripping a long workpiece in a machine tool.

Conventionally, when machining a long workpiece such as a pipe that is symmetrical in cross-section, a device that centers a part of the workpiece to be machined and then holds other parts of the workpiece is as follows:
The position of the grip was on the extension line of the centering core and could not change in the radial direction of the workpiece.
However, long workpieces often have a slight bend in the longitudinal direction in their free state. If you perform centering and gripping work on a long curved workpiece as described above, the workpiece will be forcibly held in a straight line.
If there is a bend in the workpiece, it will be corrected by the gripping force, and stress will be generated there. Therefore, when the centering device is opened to perform machining work, the released machining area tends to return to the original curved shape of the workpiece due to this stress, and the centering tends to shift. Therefore, there was a drawback that machining accuracy deteriorated.

The present invention was developed in view of the above circumstances, and the purpose is to provide a floating chuck that contributes to improving machining accuracy by gripping a long workpiece according to the curved shape even if the workpiece is curved. shall be.

Next, the present invention will be explained based on drawings showing embodiments thereof. FIG. 1 is a side view of a floating chuck 2 that grips a steel pipe 1 as a long workpiece, FIG. 2 is a cross-sectional view taken from FIG. 1, and FIG. 3 is a plan view. In the figure, 3 is a first base that is fixedly provided. Guides 4, 4 are fixed on the first base 3 in the same direction as the axis of the steel pipe 1, and a second base 5 is slidably placed on the guides 4, 4. In this embodiment, the second base 5 corresponds to the platform of the present invention. Guide members 7, 7, 7 are fixed to the column 6 in the vertical direction.
7, 7, a first frame 8 is provided so as to be vertically movable. Further, guide bars 9, 9 are vertically provided on the first frame 8, and the guide bars 9, 9 can move up and down while being guided within the guide hole 5a of the second base 5. A positioning member 10 is fixed to the side surface of the first frame 8, and a frame upper limit member 11 is attached to the column 6. When the frame 8 moves upward, the positioning member 10 collides with the frame upper limit member 11, thereby regulating the upper limit of movement of the frame 8. Further, a frame lower limit member 12 is mounted on the upper part of the second base 5. When the frame 8 moves downward, the lower part of the frame 8 collides with the frame lower limit member 12, and the lower limit of the movement of the frame 8 is regulated.

A second frame 13 is floatingly supported on the first frame 8 by the following structure. FIG. 4 is a cross-sectional view taken from FIG. 1 showing the back surfaces of both frames 8 and 13. A spring case 14 is fixedly provided on the first frame 8. A vertical hole 15 is bored in the spring case 14, a bottom plate 16 is fitted into the bottom of the vertical hole 15, and a flange 17 is mounted on the bottom plate 16. On the other hand, a spring case 18 is fixedly provided on the second frame 13 at a position above the spring case 14 of the first frame 8 and spaced apart from the spring case 14 . A vertical hole 19 is bored in the spring case 18 at a position concentric with the vertical hole 15 of the spring case 14 . An adapter 20 is fixed to the upper part of the vertical hole 19. A flange 2 is attached below the adapter 20 by an adjusting screw 21 that is screwed into the adapter 20.
2 is installed. and the spring case 1
Spring 23 is installed in the vertical holes 15 and 19 of 4 and 18.
is inserted between both flanges 17 and 22 in a compressed state. Therefore, the second frame 13 is supported on the first frame 8 by the spring 23. Further, a bush 24 is fixedly attached to the upper part of the spring case 14. On the other hand, a play hole 25 is bored in the lower part of the spring case 18 so as to surround the upper part of the bush 24 with gaps in the vertical and horizontal directions. Although the above structure supporting the second frame 13 is shown only on the right half of the frames 8 and 13 in FIG. 4, a similar structure is also provided on the left half. ing. Furthermore, a float limiting member 26 is fixed to the side surface of the frame 8 as shown in FIG. On the other hand, a protrusion 27 is fixed to the side surface of the frame 13 with its tip facing the groove 28 of the float limiting member 26. The positional relationship between the float limiting member 26 and the protrusion 27 is such that in a normal state in which the second frame 13 is supported on the first frame 8, the protrusion 27 and the groove 28 of the float limiting member 26 There are gaps a1 and a2 in the vertical direction and a gap b in the front and back direction between the two. Furthermore, FIG. 6 describes one side of the first and second frames shown in the direction of the arrow in FIG.
A slight gap (not shown) is also provided in the horizontal direction intersecting the steel pipe axis between the same protrusion 27 and the float limiting member 26 on both sides of the frame.
Therefore, the second frame 13 is connected to the first frame 8 within the range of the plane that crosses the axis of the steel pipe 1 allowed by these gaps.
can float against.

Next, the means for locking the second frame 13 will be explained. T-grooves 29, 29 are vertically cut into the left and right guide members 7, 7 provided on the column 6. A T-nut 30 is engaged with each T-slot 29, and a locking shaft 31 is integrally provided on the nut 30.
The locking shaft 31 passes through the frames 8 and 13 and is connected to a rod of a locking cylinder 32 attached to the front surface of the second frame 13. When the T-nuts 30 are pulled by each locking cylinder 32, the second frame 13 is tightened against the column 6, so that the second frame 13 cannot float relative to the first frame 8.

FIG. 5 shows a structure that prevents the second frame 13 from tilting forward when floating. A block 33 is fixed near the left and right ends of the back surface of the first frame 8. The blocks 33 face the second frame 13 in a mutually slidable manner. A through hole 34 is bored in the block 33. An annular member 35 is secured to the side surface of the block 33 with a screw 36 substantially concentrically with the through hole 34. A thrust bearing 37 is attached to the outer surface of the annular member 35. Centripetal member 38a for adjusting the thrust bearing
is inserted into a through hole 38d formed in the annular member 35 in four directions toward the axis of the support member 39,
A spring 38b inserted in the hole 38d evenly presses the outer ring of the thrust bearing 37, and exerts a centripetal action on the bearing 37 even if the second frame 13 moves slightly when floating. The adjustment screw 38c is for adjusting the spring force of the spring 38b. Also the second
The frame body 13 has the through hole 34 of the block 33.
The support member 39 is secured with a screw 40 at a position housed within the annular member 35. The support member 39
extends outward from the annular member 35, and a male thread 39a is screwed into the tip thereof. A nut 41 is screwed onto the male screw 39a and is prevented from loosening by a stopper screw 42, and the nut 41 abuts against the guide ring 43 of the thrust bearing 37. Therefore, the screwing of the nut 41 to the male screw 39a of the support member 39 is adjusted, and the second frame 13 and the block 33 are screwed together.
A gap of a predetermined size is provided between the two under normal conditions. Note that 44 is a cover.

Furthermore, a through hole 45 is bored in the block 33 at a position below the through hole 34. A cover 46 is fixed to the side surface of the block 33 with screws 47 so as to cover the through hole 45. Further, a cylinder 48 and a cover 49 are secured to the second frame 13 with screws 50 at positions that are accommodated in the through holes 45 of the block 33. A stepped hole 51 is formed in the cover 49, and a spring 54 is interposed between the stepped hole 51 and the piston 52 of the cylinder 48 so as to bias the rod 53 in the backward direction. Further, a flange 55 is fixed to a rod 53 protruding outward from the cover 49, and a thrust bearing 56 is interposed between the flange 55 and the cover 46.
is centripetalized by a centripetal member 38a which has the same structure as described above for the thrust bearing 37 and is biased by a spring 38b. Therefore, by sending hydraulic oil from the conduit 57 to extend the rod 53, it is possible to prevent the second frame 13 from tilting forward by stretching between the lower part of the second frame 13 and the block 33. .

Next, a structure for gripping a workpiece provided in the second frame 13 will be explained with reference to FIG. 2. Second
Cylinders 58 and 59 are attached to the left and right side surfaces of the frame body 13. Brackets 64, 65 are pivotally connected to the tips of piston rods 60, 61 of the cylinders 58, 59 by pins 62, 63. The bracket 6
Rack bars 66, 67 are fixed to 4, 65 in the direction toward the center of the frame 13. The rack bar 6
6 and 67 are guided by a linear slide guide 68 and a linear roller guide 69 fixedly provided at the center of the frame 13, and mesh with a pinion 71 attached to a shaft 70 supported on the frame 13. A pair of slides 72 and 73 are placed on the frame 13 so as to be movable in the lateral direction.
3 are attached to the brackets 64 and 65, respectively. Also, a steel pipe 1 is attached to the inner end of the slides 72 and 73.
Claws 74 and 75 are attached to the parts. Therefore, the piston rods 60, 61 of the cylinders 58, 59
By telescopically operating the slides 72, 73
moves, and the claws 74, 75 grip or release the steel pipe 1. The lock shafts 31 are provided above and below corresponding to the left and right guides 7, 7, respectively.
Left and right locking shafts 3 provided above
1 and 31 are inserted into elongated holes 76 and 77 provided laterally in slides 72 and 73. Therefore slide 7
2 and 73 can move without being hindered by the locking shafts 31 and 31. Further, 78 and 79 are positioning keys attached to slides 72 and 73, respectively.

Next, the operation of the floating chuck of the present invention will be explained. Among the chucks arranged to grip the steel pipe 1 at a plurality of locations, the chuck 1 or 2 grips the processed region of the steel pipe 1, for example, near the pipe end.
The floating chuck 2 of this invention is placed in the above position.
use. The floating chuck 2 is positioned by sliding the second base 5 onto the first base 3. A steel pipe 1 is fed laterally onto a chuck arranged in this way. At this time, in order to avoid interference with the steel pipe 1, the first frame 8 is lowered in advance along the column 6 to its lower limit. Also claws 74, 75
is opened wider than the outer diameter of the steel pipe 1 due to the operation of the cylinders 58 and 59. When the steel pipe 1 is set in a predetermined position, the first frame 8 rises along the column 6 to a height at which the center of grip of the claws 74, 75 approximately coincides with the axis of the steel pipe 1. In this way, the steel pipe 1 is positioned between the open claws 74 and 75. Before closing the claws 74 and 75, a positioning device (not shown) performs centering work on the processing area for one centering of the steel pipe. After the centering work is completed, each chuck grips the steel pipe 1. Regarding the floating chuck 2, the claw 7 is moved by the operation of the cylinders 58 and 59.
4 and 75 towards the steel pipe 1, and
5, the steel pipe 1 is clamped at a predetermined pressure. Next, hydraulic oil is sent to the pipe line 57 shown in FIG.
Correct the forward lean in step 3. Thereafter, the frames 8 and 13 are locked to the column 6 by the operation of each locking cylinder 32. When chucking of the steel pipe 1 is completed, the positioning device is opened and moved to a position where it will not interfere with the processing operation. The steel pipe 1 is released from the positioning device, but since the part of the steel pipe 1 close to the processed part is held by the floating chuck 2 of the present invention in the shape of the steel pipe 1, the steel pipe 1 is released from the positioning device.
Even if the steel pipe 1 is bent, the core of the processed part of the steel pipe 1 will not go out of alignment. Therefore, the processing work of the steel pipe 1 can be performed with high precision.

As is clear from the above description, the present invention contributes to improving machining accuracy by gripping a long workpiece according to its shape. In other words, since the first frame body and the second frame body only need to be locked, the locking operation time is short, the operating rate is improved, and the hydraulic control operation is easy, making it a highly practical idea.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a side view, FIG. 2 is a sectional view of FIG. 1, FIG. 3 is a plan view, and FIG. 4 is a rear view of the main part with the column removed. Fig. 1 is a cross-sectional view, Fig. 5 is a - sectional view of Fig. 4.
The sectional view, FIG. 6, is a side view taken in the direction of the arrow in FIG. 2... Floating chuck, 5... Second base, 8... First frame, 13... Second frame, 23...
Spring, 32...Lock cylinder, 74, 7
5...Claws.

Claims (1)

[Scope of utility model registration request] A first frame body that is vertically movably guided by a guide part of a column installed upright on a table; a second frame body supported in a floating manner via a pressure member, and synchronizing opening and closing operations of the second frame body in order to open the second frame body in a direction transverse to the axis of the long workpiece symmetrical in cross section. When a chuck equipped with a synchronizing device and the long workpiece symmetrical in cross section are held, the second frame body moves relative to the first frame body in accordance with the center position of the bending of the long workpiece, A floating chuck consisting of a device for locking the second frame body to the first frame body so as to maintain the same state.