JPH0640359Y2 - Rack and pinion drive safety device - Google Patents

Description

[Detailed Description of the Invention] "Industrial application field" The present invention relates to a rack and pinion drive mechanism, and more specifically, to a rack for detecting that an excessive load is applied to a movable frame driven by the rack and pinion drive mechanism. The present invention relates to a safety device of an and pinion drive mechanism.

“Prior Art” Conventionally, for example, as a rack and pinion drive mechanism used in a laser beam machine, a guide rail provided on a frame, a rack arranged in parallel with the guide rail and fixed to the frame, and the guide described above. There is known a motor provided with a movable frame provided on a rail so as to be movable back and forth, and a motor provided on the movable frame to move the movable frame forward and backward by rotating the pinion meshed with the rack forward and backward.

A focus head is provided on the movable frame so as to be movable back and forth in a direction orthogonal to the guide rail, and the necessary laser processing can be performed on the workpiece by the movement of the movable frame and the movement of the focus head.

[Problems to be solved by the invention] By the way, when the movable frame or the focus head comes into contact with an object to be processed or some obstacle during the movement of the movable frame, an excessive load is applied to the movable frame. In the past, in general, it was detected by detecting the amount of deviation between the desired position of the movable frame and the actual position, or by detecting the overcurrent of the motor. .

However, in the conventional detecting means, it takes a relatively long time from detecting the overload state to stopping the motor, so that the movable frame, the focus head, or the like is damaged, or the drive including the rack and pinion is performed. There was a risk of damaging the system.

[Means for Solving the Problems] In view of such a situation, the present invention is directed to a guide rail provided on the frame, a rack arranged in parallel with the guide rail and fixed to the frame, and retractable to and from the guide rail. A movable frame that is movably provided, a support block that is provided on the movable frame so that it can be brought into contact with and separated from the rack, a pinion that is rotatably provided on the support block, and the support block is oriented toward the rack. And a sensor for detecting that the support block is displaced from the non-operating position, and a spring for holding the pinion in the non-operating position where the pinion meshes with the rack at a regular position. A motor that is interlocked with the pinion and moves the movable frame forward and backward by rotating the pinion forward and backward, and acts on the pinion when the pinion is rotated forward and backward. A safety device for a rack and pinion drive mechanism, characterized in that when the reaction force from the rack exceeds the elastic force of the spring, the pinion is moved together with the support block in a direction away from the rack. Is.

[Operation] According to the above configuration, when the movable frame comes into contact with the obstacle and stops, whether the pinion is rotating normally or reversely with respect to the rack. The pinion is lifted from the rack due to the inclination of the tooth surfaces of the two. Then, the supporting block is displaced from the non-actuated position against the elastic force of the spring.
The sensor can detect the state and stop the motor.

The response time from the detection of normal by the sensor to the stop of the motor is substantially the same as that of the conventional device, but during that time, the pinion floats up from the rack and releases the reaction force from the rack, so that the drive system and It is possible to relieve a shocking load applied to the movable frame and prevent them from being damaged as much as possible.

[Embodiment] The present invention will be described below with reference to an illustrated embodiment. In FIG. 1, a guide rail 2 is fixed to a frame 1 in a horizontal direction (X direction), and a movable frame 3 is attached to the guide rail 2. It is provided to move back and forth. A focus head (not shown) is provided on the movable frame 3 so as to be movable back and forth in a horizontal direction (Y direction) orthogonal to the guide rail 2, and the movable frame 3 is moved in the X direction and the focus head is moved in the Y direction. Thus, the laser beam is emitted from the focus head to the work piece arranged below the focus head to perform the required laser processing.

A rack 4 is arranged and fixed on the frame 1 in parallel with the guide rails 2. On the other hand, a motor 5 is provided on the movable frame 3 and a pinion 6 which is rotated in a forward and reverse direction in association with the motor 5 is provided. It is meshed with the rack 4.
Therefore, by rotating the pinion 6 in the forward and reverse directions by the motor 5, the movable frame 3 can be moved back and forth along the guide rail 2.

The motor 5 is attached to a support block 11, and as shown in FIG. 3, one bearing portion 11a formed by projecting to both sides of the support block 11 is attached to the movable frame 3 via a connecting shaft 12. By supporting the motor, the support block 11 is swung counterclockwise in FIG.
The pinion 6 connected to the rack can be lifted from the rack 4.

A through hole 11c is formed in the other positioning portion 11b formed by projecting to both sides of the support block 11, and a positioning shaft 13 is loosely fitted in the through hole 11c to support the movable frame 3 axially. By doing so, the support block 11 can be swung by the gap between the outer peripheral surface of the positioning shaft 13 and the inner peripheral surface of the through hole 11c.

A guide rod 14 is provided upright in the radial direction of the positioning shaft 13, and the guide rod 14 slidably penetrates through a hole 15 formed above the positioning portion 11b and projects upward. The retainer 16 provided on the upper portion of the guide rod 14 is fixed to the guide rod 14, and the retainer 17 provided on the lower portion is slidably provided on the guide rod 14 so as to abut the positioning portion 11b. Retainers 16, 17
A spring 18 having a predetermined resilience is mounted between them.

Therefore, the positioning portion 11b is normally urged downward by the spring 18 to normally move the outer peripheral surface of the positioning shaft 13 and the through hole.
The pinion 8 is held in a non-actuated position where it is in contact with the inner peripheral surface of 11c, and in this state, the pinion 8 meshes with the rack 4 at a regular meshing position.

Further, a pressure plate 21 is attached to the side of the positioning portion 11b on the support block 11, and is provided on the movable frame 3 by the pressure plate 21 when the support block 11 is in the non-operating position. The contact 22a of the sensor 22 such as a limit switch is pressed.

Therefore, the contact 22a of the sensor 22 is constantly pressed in the normal state where the support block 11 is located in the non-operating position, and the sensor 22 detects that the support block 11 is displaced from the non-operating position. Contact by pressing plate 21
When the pressure of 22a disappears, it can be detected.

In the above structure, when the pinion 6 is rotationally driven by the motor 5 in the forward and reverse directions, the pinion 6 rolls on the rack 4 fixed to the frame 1, so that the movable frame 3 which axially supports the pinion 6 is moved. Can be moved back and forth in the direction. When the movable frame 3 moves normally, the support block 11 is continuously held in the non-actuated position by the spring 18, and therefore the pinion 6 is always meshed with the rack 4 at the regular position.

On the other hand, when the pinion 6 is further driven to rotate in a state where the movable frame 3 comes into contact with an obstacle and becomes immovable, for example, as shown in FIGS. Since the reaction force on the meshing surface with 4 acts, the pinion 6 is biased in the direction of floating from the rack 4.

When the urging force exceeds the set load of the spring 18, the support block 11 swings counterclockwise in FIG. 3 around the bearing portion 11a, so that the pressing plate 21 provided on the positioning portion 11b causes the sensor 22 to move. The support 22 is separated from the contact 22a, so that it is detected that the support block 11 is displaced from the inoperative position, and the operation of the motor 5 is stopped.

The response time until an abnormality is detected by the sensor 22 and the motor 5 is stopped is substantially the same as that of the conventional device, but during that time, the pinion 6 floats up from the rack 4 and escapes the reaction force from the rack 4. As a result, the shocking load applied to the drive system including the rack 4 and the pinion 6 and the shocking load applied to the movable frame 1 or the focus head and the like provided on the movable frame 1 can be mitigated. In comparison, those damages can be prevented as much as possible.

In the above embodiment, the support block 11 is attached to the movable frame 1.
Although it is swingably attached, it may be provided so as to be linearly displaceable. In the above embodiment, the motor 5
Although the pinion 6 is rotatably supported by the support block 11 via the pinion 6, the pinion 6 is directly rotatably supported by the support block 11, and the motor 5 is attached to the movable frame 3. 5 and 5 may be interlocked via an expansion joint.

[Advantage of Invention] As described above, according to the present invention, for example, when the movable frame comes into contact with an obstacle or the like and stops, even if the pinion rotates forward with respect to the rack, the reverse rotation is performed. Even if it is, the pinion can be lifted from the rack and the reaction force from the rack can be released, so the shocking load applied to the drive system and movable frame can be alleviated and damage to them can be prevented. The effect of being able to prevent it is obtained.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention, and FIG.
FIG. 3 is a side view of an essential part of the drawing, FIG. 3 is a cross-sectional view taken along line III-III of FIG. 2, and FIGS. 4 and 5 are explanatory views for explaining states of reaction forces from the rack 4 applied to the pinion 6, respectively. It is a figure. 1 ... Frame, 2 ... Guide rail 3 ... Movable frame, 4 ... Rack 5 ... Motor, 6 ... Pinion 11 ... Support block, 12 ... Connecting shaft 13 ... Positioning shaft, 18 ... Spring 22 ... Sensor

Claims (1)

[Scope of utility model registration request] 1. A guide rail provided on a frame, a rack fixed parallel to the guide rail and fixed to the frame, a movable frame provided on the guide rail so as to be movable back and forth, and the movable frame, A support block that can be brought into contact with and separated from the rack, a pinion that is rotatably provided on the support block, and a biasing force of the support block toward the rack with a predetermined elastic force. A spring that holds the non-operating position that meshes with the regular position, a sensor that detects that the support block is displaced from the non-operating position, and a pinion that is interlocked,
A motor for moving the movable frame forward and backward by rotating the pinion forward and backward, and when the reaction force from the rack acting on the pinion when the pinion is rotated forward and backward exceeds the elastic force of the spring. A safety device for a rack and pinion drive mechanism, wherein the pinion is moved together with the support block in a direction away from the rack.