JPS6333976B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a work loader used for loading or unloading a workpiece on a machine tool such as a lathe, and in particular a linear arm having a clipper at the tip; The present invention relates to an improvement in a work loader including a drive unit that moves its arm in its axial direction.

(Prior Art) Conventionally, this type of work loader was operated by an electric motor, and therefore the arm was operated against the inertia of the arm, so it was greatly affected by the inertia, and high-speed operation was not possible. However, there were problems in that it was difficult to improve the stopping accuracy. Further, it is dangerous to approach this workload, and it is not desirable in terms of safety.

(Summary of the Invention) An object of the present invention is to provide a workload that enables high-speed and high-precision operation and is also preferable in terms of safety.

The work loader according to the present invention is characterized by a linear arm drive section, which includes a threaded section that cannot rotate but is movable in the axial direction, and a female screw section that can rotate but is immobile in the axial direction. The ball screw includes a cylinder device in which one end of the male threaded portion of the ball screw is connected to a piston, and the cylinder device and the ball screw cause the toothed wheel provided on the female threaded portion of the ball screw and the A force counteracting gravity is applied to the arm via an engaging member fixed along the arm, making the arm nearly weightless and minimizing the influence of inertia.

(Example) Next, an example of the present invention will be described with reference to the drawings. As shown in FIG. 2, this work loader 1 basically includes a linear arm 2 and a drive section 3 that moves the arm forward or backward in the axial direction.
It consists of The drive unit 3 may be installed on a movable trolley (not shown) or on a fixed support. A gripper 4 for gripping a workpiece is attached to the tip of the arm 2, and the gripper 4 consists of a sensing part and an operating part such as an air cylinder.

The present invention is characterized by a drive unit 3, and as shown in FIG. 1, this drive unit 3 includes a ball screw 5 and a cylinder device 6, and the cylinder device 6 is an air cylinder in that it does not become dirty. It is preferable that
It may also be a hydraulic cylinder. One end of the male threaded portion 7 of the ball screw 5 is connected to the piston 8 of the cylinder device 6, and the male threaded portion 7 is configured to be movable in the axial direction but not rotatable. In the illustrated example, a suitable number of guide rods 9 are fixed in the cylinder device 6 and pass through the piston 8 in a sealed manner. The female threaded portion 10 of the ball screw 5 is connected to a pair of bearings 1
1, 11' supported on the housing 12;
It is rotatable but cannot move in the axial direction. Note that 5' is a ball included in the ball screw 5.

Furthermore, the drive section 3 includes a toothed wheel 13 attached to the outer periphery of the female threaded section 10 and an engaging member 14 fixed along the arm 2 and arranged in a straight line to engage the toothed wheel 13. 15 is a screw that fixes the toothed wheel 13 to the female threaded portion 10. Preferably, as shown in the figure, a pinion is used as the toothed wheel 13, and the engaging member 1 is connected to the pinion.
For 4, a rack is used. If desired, a brake 1 is provided to stop the rotation of the female threaded portion 10 at an appropriate position.
6. For example, a spring brake is installed.

In FIG. 1, reference numeral 17 indicates a pressure source for supplying pressurized fluid to the cylinder device 6, that is, if it is an air cylinder, it is a compressor or a gas cylinder, and if it is a hydraulic cylinder, it is a hydraulic pump. The supply line 18 between them is equipped with a pressure regulating valve 19, which is adjusted so as to apply a pressure to the cylinder device 6 that balances the gravitational force of the arm 2.

In a preferred form, as shown in FIG. 3, a motor 20 for rotating the female threaded portion 10 is provided to move the arm 2, and an encoder 21 for capturing the position of the arm 2 is installed at an appropriate position. . These pressure regulating valve 19, motor 20 and encoder 21 are connected to a computer (not shown). Note that the motor 20 does not necessarily have to be provided in association with the female threaded portion 10, and the motor 20 may be provided to rotate another toothed wheel 22 that meshes with the engaging member 14, as shown in phantom lines in FIG. It may be provided. Note that 23 is a guide roller of the arm 2.

(Function) During operation, arm 2 is adjusted by adjusting the pressure regulating valve 19.
applies a force to the piston 8 that balances the gravitational force of , so that the arm 2 remains weightless. Note that the pressure of the piston 8 becomes a force in the axial direction of the male threaded portion 7, which appears as a force that rotates the female threaded portion 10, and therefore the toothed wheel 13 and the engagement member 1.
A load is applied to arm 2 via 4. In this manner, the arm 2 is moved by operating the motor 20 in a state of zero gravity, and as shown in FIG. 5, the gripper 4 is placed at the position _A1 , and the workpiece is gripped there. At the same time as the arm 2 moves, the female thread part 1
0 also rotates, and accordingly, the external threaded portion 7 moves in the axial direction, and the piston 8 is at the position shown by the solid line in FIG.
Located at A′ ₁ . Next, the motor 20 is operated to move the arm 2, and the gripper 4 is moved to the position _A2 in FIG.
For example, move to the chuck position of a lathe and release the workpiece there. At this time, the piston 8 is at position _A'2 . Then return to position _A1 again. Such movement is performed by operating the motor 20 by the computer in response to a signal from the encoder 21. Since the arm 2 is moved in a zero gravity state, the motor 20 may be small.

If the arm 2 is moved by the motor 20, accurate positioning can be achieved.

Note that although the above case describes mounting a workpiece on a machine tool, it goes without saying that it can also be used when receiving a processed workpiece from a machine tool and moving it to a predetermined position.

(Effects of the Invention) According to the present invention, the arms constituting the work loader are operated in a zero-gravity state or in a state close to zero gravity, so there is no influence of inertia, and therefore it is possible to operate at high speed and accurately. Further, only a small amount of power is required to move the arm, so if the arm hits a human body, the arm simply stops, and there is no harm to the human body, so it is safe.

[Brief explanation of the drawing]

FIG. 1 shows the main parts of the work loader according to the present invention, and is a sectional view taken along the line A-A in FIG. 2, FIG. 2 is a perspective view of an example of the work loader according to the present invention, and FIG. 3 is another embodiment 4 is a cross-sectional view showing a portion of the line B--B in FIG. 1, FIG. 5 is a schematic diagram showing the position during operation, and FIG. FIG. 3 shows the position of the piston of the cylinder device corresponding to the illustrated state; In the figure, 2...Arm, 3...Drive unit, 4...Gripper, 5...Ball screw, 6...Cylinder device, 7...Male thread section, 8...Piston, 9...Guide rod, 10... ...Female threaded portion, 13...Toothed wheel, 14...Engaging member, 20...Motor.

Claims (1)

[Scope of Claims] 1. A work loader including a linear arm having a gripper at the tip and a drive unit that moves the arm in its axial direction, wherein the drive unit cannot rotate but can move in the axial direction. A ball screw comprising a threaded portion and a female threaded portion that can rotate but remains immovable in the axial direction, a cylinder device in which one end of the male threaded portion of the ball screw is connected to a piston, and a female threaded portion of the ball screw. a pinion provided on a threaded portion; a rack fixed along the arm and engaged with the pinion; one end of the male threaded portion fixed to the piston; a guide rod extending sealingly through the piston; Accordingly, rotation of the male threaded portion is prevented, and the driving portion further includes a motor for moving the arm and a brake for stopping rotation of the female threaded portion. Workloader. 2. The work loader according to claim 1, wherein the cylinder device is an air cylinder. 3. The work loader according to claim 1, wherein the cylinder device is a hydraulic cylinder.