Hereinafter, embodiments of the present invention are described based on accompanying drawings.
In a first embodiment of the present invention, as shown in
The above-mentioned gripping claw 4 is exchangeably attached through bolts 7 to an attachment seat 6, which is attached to a front surface of the master jaw 3 through bolts 5 in the illustrated case.
Moreover, behind the master jaw 3 inside of the rotating body 1, a moving-forward and backward unit slid forward and backward by applied fluid pressure.
With the above-mentioned moving-forward and backward unit S, as shown in
In some cases, a tube journal (illustration is omitted) that forcibly feeds air to a coolant tube may be arranged behind the journal 91.
Furthermore, with sliding of the piston 9, the master jaw 3 is forcibly slid by the interlocking unit C between a grasping direction and a grasping release direction, and a workpiece B is drawn in at the time of grasping.
The above-mentioned interlocking unit C is configured such that as shown in
Consequently, the master jaws 3 slide in a central direction and in a circumferential direction with the sliding of the pistons 9 to draw in the workpiece B at the time of grasping.
Obviously, the sliding of the pistons 9 may be converted to the sliding of the master jaws 3 in a perpendicular direction by another mechanism.
With the disc 14, two front and back discs make a pair, and both rear sides of each of the master jaws 3 are fitted into the radial recessed groove 2 provided in a front surface of the rear disc 14 for guiding, and a front portion of the master jaw 3 penetrates a long rectangular hole 20 of the front disc 14 (in the radial direction and slidably within a range in the grasping direction and in the grasping release direction), and the two discs 14 making a pair are integrated by bolts 21 to slidably embrace the master jaws 3 by the front and rear discs 14, 14.
Moreover, behind the master jaws 3 inside of the hollow portion 13, weights 28 that slide in the central direction of the rotating body 1 and in the circumferential direction thereof are provided so as to face the respective master jaws 3.
Each of the above-mentioned weights 28 is composed of an arcuate portion 29 and a cylindrical leg portion 30 projected from the center between both ends of this arcuate portion 29 in the central direction, and a spring 31 inserted into the leg portion 30 has one end abutting against a bottom of the leg portion 30 and the other end abutting, through a slide pin 33, against an outer circumferential surface of shafting 32 oriented to the front surface of the rotating body 1 via the inside of the hollow portion 13, at the center of the rotating body 1 so as to gives the weight 28 protruding force oriented in the circumferential direction of the rotating body 1.
Consequently, the weight 28 instantly slides in the circumferential direction of the rotating body 1 by the centrifugal force with the rotation of the rotating body 1.
Furthermore, a through-hole 34 for a supporting point is provided in a position on the rear disc 14 opposed to each of the master jaws 3, and one end of a lever 35 penetrating this through-hole 34 is fitted into an engagement hole 36 at the center between both the ends of the arcuate portion 29 of the weight 28, while the other end of the lever 35 is fitted into an engagement hole 37 at the center of the master jaw 3.
At this time, a distance from the supporting point (through-hole 34) of the lever 35 to the one end on the weight 28 side is made larger than a distance from the supporting point (through-hole 34) of the lever 35 to the other end on the master jaw 3 side (the ratio shown in the figure is 2:1), and this ratio allows the centrifugal force of the weight 28 to be doubled and applied to the master jaw 3.
Reference numeral 40 in the figure denotes a penetrating hole of the shafting 32 provided at the center of the disc 14, reference numeral 41 denotes an O ring arranged along an edge of the long hole 20 on the front surface of the front disc 14, which prevents coolant liquid and cutting debris from entering from a lapping surface of the master jaw 3 and the attachment seat 6. Reference numeral 43 denotes a seating stopper of the workpiece B, which has a seating surface 63 positioned in a longitudinal direction of the workpiece B, and a sensor bore 64 for seating detection.
The above-described configuration allows the workpiece B to be fitted between internal ends of the gripping claws 4.
Next, when the fluid is supplied to the hollow chamber 8 from the second passage 11 to move the piston 9 backward and make the rod 16 travel backward, the respective master jaws 3 are slid in the central direction through the interlocking unit C to grip the workpiece B by the gripping claws 4. Furthermore, the fluid continues to be constantly supplied to the hollow chamber 8 to keep the piston 9 traveling backward, until the disc 14, the attachment seats 6 and the gripping claws 4 become integral to be drawn in at a certain amount (be moved to the left). Consequently, the gripped workpiece B is stabilized by making close contact with the seating surfaces 63, which prevents the floating-up of the workpiece B.
On the other hand, the weights 28 are slid in the circumferential direction by the centrifugal force occurring with the rotation of the rotating body 1.
Force (moment) that slides the respective master jaws 3 in the central direction acts on the master jaws 3 by inclination of the levers 35 with sliding of the weights 28.
With this acting force, since the distance between the supporting point of the lever 35 to the one end engaging with the weight 28 is made longer than the distance between the supporting point of the lever 35 to the other end engaging with the master jaw 3, the centrifugal force of the weight 28 is doubled to act on the master jaw 3.
This allows the machining to be performed while maintaining the gripping force having strong drawing-in without weakening of the gripping force of the gripping claw 4 (without any effect by the centrifugal force acting on the master jaw 3, the attachment seat 6 and the gripping claw 4).
Moreover, since even during machining, the supply of the fluid from the second passage 11 is continued, the drawing-in of the workpiece B by the disc 14, the master jaws, 3, the attachment seats 6, and the gripping claws 4 is performed, which, at high accuracy, prevents the workpiece B from jumping out.
According to a second embodiment of the present invention, the slide recessed grooves 2 for the master jaws 3 are provided inside of the rotating body 1.
A reason of the above-described provision of the recessed grooves 2 inside of the rotating body 1 is to prevent the coolant liquid used during machining, cutting debris and the like from entering the inside of the recessed groove 2 to hinder the smooth sliding of the respective master jaws 3, and to require frequent maintenance.
Therefore, an O ring 51 is interposed in an outer circumference of the front disc 14 fitted into the hollow portion 13 in the front surface of the rotating body 1, and an O ring 52 is interposed in an inner circumference of the disc 14.
The long hole 20 in the sliding range of each of the master jaws 3 is provided in the position of the front disc 14 opposed to each of the master jaws 3, the front portion of the master jaw 3 slidably penetrates this long hole 20, and the gripping claw 4 is attached to the penetrating front surface of the master jaw 3 with the attachment seat 6 interposed.
An O ring 41 to come into contact with a back surface of the attachment seat 6 is arranged along an edge of the long hole 20.
According to a third embodiment of the present invention, as shown in
The above-mentioned spring 61 is fitted into a recessed portion 67 provided in an opposed surface between a back wall of the hollow portion 13 and the disc 14.
A collar 62 is fitted into each of the bolts 21 which bind the disc 14 not to rotationally move and are screwed in the disc 14 from the back wall of the hollow portion 13, and a terminal vamplate portion 68 of this collar 62 is fitted into a diameter-expanded recessed step portion 70 having a large diameter on the insertion end side of a penetrating hole 69 for the collar 62, which is provided in the back wall of the hollow portion 13 to limit a protrusion amount of protruding force given by the spring 61 to a certain level and to permit the disc 14 to slide in certain amount of sliding to the back wall side of the hollow portion 13.
Consequently, the centrifugal force of the weights 28 is doubled by the levers 35 and applied to the master jaws 3 to grasp the workpiece B. Following this action, the disc 14 having the gripping claws 4 is drawn back against the protruding force by the spring 61 by the fluid continuing to be applied to the pistons 9, so that the workpiece B is further drawn in until it comes into close contact with the seating surfaces 63 while being grasped.
This action of the drawing-back increases the function such that after the grasped workpiece B is grasped in as described above, the workpiece B is further drawn in, which prevents the floating-up or jumping-out of the workpiece B. This enables high-accuracy machining and machining under fast operation (rotation).
Number | Date | Country | Kind |
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2006-198807 | Jul 2006 | JP | national |