JPH081571A - Chuck - Google Patents

Abstract

PURPOSE:To adjust an interval between chuck claws when they are opened to a suitable size to a work. CONSTITUTION:Three pairs of guide rails are radially installed on a frame 1, sliders 3 are supported to be freely slidable along the respective guide rails, and chuck pawls 5 are fixed on the respective sliders 3. A screw cylinder 7 is supported inside the frame 1 to elevate freely, and an L-shaped lever 10 which is engaged with the screw cylinder 7 at one end, and engaged with the slider 3 at the other end is rotatably supported in the frame 1. A compression air cylinder 19 is provided in the frame, and a piston 20 is freely slidably engaged in it. A drive shaft 21 is installed on the piston 20 to be freely rotatable. and threaded with the screw cylinder 7. A motor 25 to drive rotation of the drive shaft is also provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chuck attached to an arm of a device for supplying and unloading a work.

[0002]

2. Description of the Related Art A chuck in which chuck claws are opened and closed in parallel is conventionally known. This type has a large stroke and is convenient because it can grip a large work to a small work.

[0003]

However, in the parallel opening / closing chuck having a large opening / closing stroke, the distance between the works must be sufficiently large so that the chuck jaws do not hit the adjacent works. Further, in a narrow space, the work cannot be supplied because the nail interferes.
Moreover, since the stroke is large, it takes time to open and close the chuck claws. An object of the present invention is to eliminate such problems of the conventional parallel open / close chuck.

[0004]

A plurality of guide rails are attached to a frame, a slider is slidably supported along each guide rail, and a chuck claw is fixed to each slider. A screw cylinder is movably supported inside the frame, one end of which is engaged with the screw cylinder and the other end of which is rotatably supported by the frame. A compressed air cylinder is provided in the frame, and a piston is slidably fitted therein. The drive shaft is extended from the piston and screwed into the screw cylinder. Further, a motor for rotating the drive shaft is provided.

[0005]

In use, first, the drive shaft is rotated by the motor to raise the screw cylinder. Then, the slider moves via the lever and the gap between the chuck claws becomes narrow. In this way, the distance is adjusted to be slightly larger than the work to be gripped.
Next, compressed air is sent to the cylinder to raise the screw cylinder together with the piston. In this way, the gap between the chuck claws is reduced,
Grab the work.

[0006]

EXAMPLE A radial pattern is formed on the lower surface of a substantially cylindrical frame 1.
A pair of guide rails are provided, and a slider 3 is attached to each guide rail.
Each is slidably supported. Chuck claws 5 extend downward from each slider 3.

A central hole 6 is formed in the frame 1, a screw cylinder 7 is fitted in the frame 1 so as to be vertically movable, and slits 9 are radially formed from the central hole 6, and an L-shaped lever 10 and a pin 11 are formed in each slit. It is rotatably supported by. The L-shaped lever 10 connects the slider 3 and the screw cylinder 7 so that the chuck claw 5 opens and closes when the screw cylinder 7 moves up and down. That is, the slider 3 is provided with the pin 12 horizontally, and the slider 13 having a square cross section is rotatably supported by the pin 12. A pin 15 is also provided in a notch formed around the screw cylinder, and a slider 16 having a square cross section is rotatably supported by the pin 15. U-shaped notches 17 are formed at both ends of the L-shaped lever 10, and the sliders 13 and 16 are engaged with the notches 17.

A pneumatic cylinder 19 is formed in the upper part of the frame, and a piston 20 is fitted therein. Piston 20
Is hollow and rotatably supports the drive shaft 21 therein.
A large diameter part is formed in the lower part of the drive shaft, and a male screw 2
2 is carved and is carved in the center hole of the screw cylinder 7
Screw it in.

An electric motor 25 is attached to the frame 1,
The pinion 26 fixed to the output shaft meshes with a large gear 29 attached to an intermediate shaft 27 mounted on the frame 1, and a small gear integrated with this meshes with a spur gear 31 fixed to the upper end of the drive shaft 21. ing.

In this chuck, the spacing between the chuck claws is adjusted to be slightly larger than the spacing between the workpieces to be held, and then the original chucking operation is performed. The chuck claw spacing is adjusted by driving a motor. Now, it is assumed that the chuck claws are most opened as shown by the solid line in FIG. 1 (state A). The motor turns and the gears 26, 27, 29, 3
The drive shaft 21 rotates through 0 and 31. Since the screw cylinder 7 screwed with the drive shaft 21 is coupled to the L-shaped lever 10 and cannot rotate, it rises. Then, L-shaped lever 1
0 rotates about the pin 11, the slider 3 moves inward, and the gap between the chuck claws 5 becomes narrow.

The distance between the chuck claws can be known from the rotary encoder 32 attached to the intermediate shaft 27. The amount of rise of the screw cylinder 7 may be read by a potentiometer (not shown). In this way, the gap between the chuck claws is narrowed to be a little larger than the work to be chucked. This state is shown as state B in FIG.

The operation of actually gripping the work is performed using compressed air. When compressed air is sent into the inside of the cylinder 19 from the lower port 35, the piston 20 moves up, and the drive shaft 21 and the screw cylinder 7 screwed with the drive shaft 21 also move up. At this time, the spur gear 31 at the upper end of the drive shaft also rises as shown by the chain line in FIG. 1, but since the small gear 30 meshing with this is made vertically long, the spur gear does not disengage from it.

When the screw cylinder 7 is raised, the L-shaped lever 10 is rotated, the slider 3 is moved inward, the gap between the chuck claws 5 is narrowed, and the work 37 is gripped (C state, see also FIG. 3). When the work is gripped by the chuck, the movement of the piston 20 stops, but since a compressible working fluid (air pressure) is used, there is no overload. Further, the force for clamping the work is almost constant, and the clamping force is almost determined by the magnitude of the air pressure.

When compressed air is sent to the upper port 36, the piston 20 is lowered and the chuck claw 5 is opened to return to the B state, so that the work 37 which has been gripped is released.

This chuck is attached to the tip of the arm of the robot and supplies and conveys the work.

When a large number of workpieces are chucked repeatedly, the drive shaft 21 may rotate due to the vibration when the piston moves, and the adjusted position (state B) of the chuck claw may shift. Therefore, a preload ring 40 having a male screw engraved on its periphery is screwed into the female screw 23 of the screw cylinder 7, and this preload ring is supported on the drive shaft 21 so as to be slidable in the axial direction. Reference numeral 41 is a key for attachment. Further, the preload ring 40 is biased upward by the spring 42 (may be biased downward). By doing so, play between the female screw of the screw cylinder and the male screw of the drive shaft is apparently eliminated, and loosening of the drive shaft 21 which is exposed to vibration can be prevented.

Although not shown in the drawings, a suction cup communicating with the vacuum pump may be provided on the lower surface of the chuck claw so that the work can be sucked and lifted.

[0018]

According to the chuck of the present invention, the drive shaft is rotated by the motor and the screw cylinder screwed onto the drive shaft is moved up and down to adjust the gap between the chuck claws when opened to a size suitable for the work. Since the work can be held, it is not necessary to arrange the works to be grasped apart from each other more than necessary, and the works can be supplied to a narrow space. When the work is actually clamped, the chuck claw is moved by the pneumatic cylinder, so that there is an effect that the work can be clamped with a substantially constant force.

When the preload ring is screwed into the screw cylinder, axially slidably supported by the drive shaft, and axially biased by a spring, when repeatedly chucking using an air cylinder. In addition, it is possible to prevent the drive shaft from loosening around due to vibration, and therefore, there is an effect that the position of the chuck claw adjusted according to the work to be gripped does not shift.

[Brief description of drawings]

FIG. 1 is a sectional view of a chuck.

FIG. 2 is a plan view of the chuck, a part of which is shown in section.

FIG. 3 is a bottom view of the chuck.

FIG. 4 is an elevational view of a chuck.

[Explanation of symbols]

 1 Frame 2 Guide Rail 3 Slider 5 Chuck Claw 7 Screw Cylinder 10 Lever 19 Cylinder 20 Piston 21 Drive Shaft 22 Male Thread 23 Female Thread 25 Motor 40 Preload Ring

Claims (2)

[Claims] 1. A plurality of guide rails (2) provided on a frame (1), sliders (3) slidably mounted along the guide rails, and chuck claws fixed to the sliders (3). 5), a screw cylinder (7) that is movably supported inside the frame, and a rotatably supported frame, and one end engages with the screw cylinder and the other end engages with the slider. Then, a lever (10) for converting the up-and-down movement of the screw cylinder into a movement of the slider, a compressed air cylinder (19) provided in the frame, and a piston (20) slidably fitted in the cylinder. ), A drive shaft (21) extending from the piston, and a motor (25) for rotationally driving the drive shaft, and the drive shaft is formed with a male screw (22), which is the center of the screw cylinder. Screwed into the female screw (23) engraved in the hole Chucking. 2. A preload ring (40) having a male screw on its peripheral surface and screwed with a female screw of the screw cylinder is slidably attached to the drive shaft in the axial direction, and the preload ring is a spring (42). The chuck according to claim 1, wherein the chuck is biased in the axial direction.