JPS6234648Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a cam lock chuck which is capable of gripping various workpieces having a wide range of dimensions and which enables automatic reversal machining of stepped workpieces.

Conventionally, cam lock chucks have been widely used because they have a simple structure and are lightweight as floating chucks with self-aligning properties, and moreover, the reaction force applied to the workpiece during gripping is small. For example, there is Japanese Patent Application Laid-open No. 139811/1983. However, because this cam lock chuck has a narrow range of dimensions that it can grip, it is unable to automatically reverse and grip stepped workpieces with slightly large steps, and there are concerns about the reliability of gripping and releasing workpieces. are doing. Therefore, there is a drawback that both ends of the workpiece cannot be automatically machined with one machine tool.

Therefore, in order to solve the above-mentioned drawbacks, this invention forms the workpiece gripping contact part of the cam lock chuck's pawl in multiple stages, so that it is possible to grip the workpiece even if there is a dimensional difference in the gripping diameter, and it is possible to replace the pawl. A ratchet wheel for gripping and releasing and a ratchet wheel for fixing the jaw holder are provided to enable automatic reversal machining of stepped workpieces without any need for a grip release. It is an object of the present invention to provide a chuck with improved reliability by providing a control means for operating a drive means for rotating the chuck.

Embodiments of the present invention will be described below based on the drawings. Figure 1 shows the cam lock chuck of the present invention attached to the tip of the main shaft of a cylindrical grinder.A pulley 3 is rotatably attached to the main shaft sleeve 1 via a bearing 2, and the front end of the pulley 3 A bearing retainer cover 4 is fixed. A main shaft 5 is supported within the main shaft sleeve 1 so as to be movable in the axial direction,
A center 6 is fitted to the tip of the main shaft 5. A collar 7 is fixed to the front end surface of the lid 4 concentrically with the main shaft 5, and a ring-shaped fixing ratchet wheel 8 is fixed to the center of the collar 7. Further, a ring-shaped opening ratchet wheel 9 is rotatably attached to the front end of the collar 7 by a clamping member 10, and a pin 9a protruding from the back surface of the ratchet wheel 9 and the clamping member 10 are attached to the front end of the collar 7. A locking piece 10a fixed to the back surface of
A tension spring 34 is tensioned between the two and always biases the ratchet wheel 9 counterclockwise in FIG. A ring-shaped claw holder 11 is fixed to the front surface of the clamp holder 10. In this example, the claw holder 11 is arranged at three points on the circumference.
Window portions 12 are opened in the radial direction at equal locations, and each window portion 12 is provided with a claw body 13 radially, and is pivoted by a pin 14 so as to be able to rotate in a plane perpendicular to the main axis. has been done. The claw body 13 has a wide fan-shaped portion that protrudes inward from the ring-shaped portion of the claw holder 11, and its distal end arc-shaped portion 15 is divided into two stages with different distances from the pin 14 serving as a pivot point. ing. Each arcuate portion 15 has a cam shape with respect to the pivot point, and the pin 14
It is formed so that when it rotates around , it grips the workpiece it grips gradually more strongly. Further, an outwardly projecting portion 16 of the pawl body 13 from the holding body 11 has a bifurcated shape, and grips the tip of a pin 17 implanted in the opening pawl wheel 9. A pin 16a is implanted at one end of each bifurcated part, and a tension spring 33 is tensioned between this pin and a protruding piece 11a protruding from the claw holder 11. In the figure, the claw body 13 is biased clockwise, that is, in the direction in which it grips the workpiece. A first cylinder device 20 is attached to a plate-shaped chuck frame 19 fixed to the front surface of the headstock body 18, and a piston rod 21 of a piston 40 of this cylinder device 20 is attached.
A first ratchet pawl 22 is pivoted at the tip of the ratchet pawl 22 so as to be always biased in the direction of engagement with the fixing ratchet wheel 8 by a spring (not shown).

A ring-shaped clamping body 23 is fixed to the frame 19 concentrically with respect to the main shaft 5 so as to cover the collar 7, and a disk-shaped claw support plate 24 is rotatably supported on the clamping body 23. has been done. A pin 26 is fixed to a protrusion 25 at one location on the outer periphery of the claw support plate 24. A second ratchet pawl 27 that engages with the opening ratchet wheel 9 is pivotally attached to the tip of the pin 26, and a spring 28
7 is always biased so as to engage with the opening ratchet wheel 9. A second cylinder device 29 is pivotally attached to the frame 19, and the tip of the piston rod 30 of the piston 44 of the cylinder device 29 is pivotally attached to the protrusion 25 of the pawl support plate 24. Further, a member 31 for releasing the engagement between the opening ratchet wheel 9 and the second ratchet pawl 27, and a cover 32 for covering the cam lock chuck are attached to the frame 19. 35 is a two-position switching solenoid valve, 36, 3
9, 41, 42, 43, and 45 are conduits, 46 is a check valve, 37 is a throttle valve, and 38 is a terminal block.

Next, the operation will be explained with reference to FIG. It is assumed that the first grinding process on one side of the workpiece held by the cam lock chuck has been completed. FIG. 3 The solenoid valve 35 is energized and switched to the I position, and pressure oil is guided from the pipe 36 through the throttle valve 37, the terminal block 38, and the pipe 39 to the upper chamber a of the first cylinder device 20. The piston 40 of the first cylinder device 20 advances and the first ratchet pawl 22 engages with the fixing ratchet wheel 8. The oil in the lower chamber b of the first cylinder device 20 is connected to the pipe 41 and the terminal block 3.
8, is discharged from the solenoid valve 35 through the pipe 42. When the piston 40 reaches the forward end, the upper chamber a of the first cylinder device 20 communicates with the conduit 43 and leads pressure oil to the left chamber c of the second cylinder device 29. Therefore, the piston 44 of the second cylinder device 29 moves forward, rotates the pawl support plate 24 having the protrusion 25 clockwise, and releases the second ratchet pawl 27 from the release member 31. engage with. The piston 44 continues to move forward, but at this time, the locking ratchet wheel 8 engages with the first ratchet pawl 22 and is prevented from rotating, so the collar 7, pawl holder 11, and pin 14 do not rotate. Claw release ratchet wheel 9
can only be rotated clockwise.

As the opening ratchet wheel 9 rotates, the pin 17 also turns clockwise, so the pawl body 13 rotates clockwise in FIG. 2 using the pin 14 as a fulcrum, and the workpiece is released from its grip. The oil in the right chamber d of the second cylinder device 29 is led from the pipe 45 to the pipe 41 and is discharged from the solenoid valve 35. Thereafter, the workpiece is taken out from the cam lock chuck by a loader device (not shown), turned over, inserted into the cam lock chuck again, and supported by the center 6. and solenoid valve 35
is demagnetized and switched to the position by the spring, the pressure oil flows through line 42, terminal block 38, and line 4.
1 to the lower chamber b of the first cylinder device 20, and at the same time guided to the right chamber d of the second cylinder device 29 through the conduit 45, both the piston 40 and the piston 44 are retracted, and the first Ratchet claw 2
2 and the second ratchet pawl 27 are disengaged from the locking ratchet wheel 8 and the releasing ratchet wheel 9, respectively.

The second ratchet pawl 27 is then made to ride on the release member 31. Second cylinder device 29
The oil in the left ventricle is transferred from the pipe 43 to the first cylinder device 20
Regardless of the position of the piston 40, it communicates with the pipe 39 through the check valve 46 inside, and is discharged together with the oil in the upper chamber a of the first cylinder holder 20. As a result, the opening ratchet wheel 9 is rotated counterclockwise by the tension spring 34, and the pawl body 13 rapidly rotates counterclockwise using the pin 14 as a fulcrum, thereby automatically gripping the workpiece. At this time, even if the diameters of the workpieces to be gripped are different, the contact portion of the claw body 13 for gripping the workpieces is formed in two stages, so that the workpieces with different diameters can be gripped reliably. After the gripping of the workpiece is completed, the second grinding process is started.

As described in detail above, according to the present invention, the cam portion of the claw body of the cam lock chuck that contacts the workpiece is formed in two stages, so that workpieces of different diameters can be reliably gripped. Therefore, it is possible to invert and grip the stepped workpiece without replacing the claw body, and it is possible to automatically invert the workpiece with one machine tool. Further, since two ratchet wheels are used to prevent the claw holder from rotating when the grip on the workpiece is released, the workpiece can be released reliably and quickly. Furthermore, since the ratchet wheel for releasing the workpiece is rotated after the engagement between the ratchet wheel for preventing drag and the ratchet pawl is completed, the workpiece is released more reliably and reliability is improved.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of the cam lock chuck of the present invention, FIG. 2 is a cross-sectional view taken from FIG. 1, and FIG. 3 is a hydraulic circuit diagram. 8...Fixing ratchet wheel, 9...Release ratchet wheel, 11...
...Claw holder, 13...Claw body, 17...Pin, 20
...First cylinder device, 29...Second cylinder device, 33...Tension spring (first spring member), 34...
...Tension spring (second spring member).

Claims (1)

[Scope of utility model registration request] The contact part with the workpiece has a plurality of cam shapes with different distances from the pivot point, and the claws are gripped by rotating, and the plurality of claws are pivoted radially so that they are concentric with the main shaft. A disc-shaped pawl holder is fixed to a member that rotates together with a rotatably supported pulley, and the pawl is clamped by a bifurcated portion of the pawl on the opposite side of the cam-shaped contact portion with respect to the pivot point of the pawl. The workpiece is gripped by the pin, the disc-shaped grasping and releasing ratchet wheel which is rotatably supported concentrically on the jaw holder and has the pin implanted therein, and the jaw body. A first spring member, which is stretched between the bifurcated part of the claw body and the claw holder, always biases the claw holder in the direction in which the workpiece is gripped by the claw body. a second spring member that urges the grasping release pawl wheel and is tensioned integrally with the grasping release pawl wheel and the pawl holder; A driving means for rotating the car,
A disc-shaped pawl holder fixing ratchet is concentrically fixed to the pawl holder, and a disc-shaped pawl holder fixing ratchet is engaged with the pawl holder fixing ratchet when the grip on the workpiece is released to prevent rotation of the pawl holder. A cam lock chuck characterized in that it comprises an engaging means for blocking and a control means for operating the driving means for rotating the grasping and releasing ratchet after the engaging means is operated.