JP2000127078A - Gripper with claw position detecting function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the need of position adjustment for a sensor in setup replacement, prevent a trouble due to maladjustment and shorten the operation time required for setup replacement by providing a gripper having a function of detecting the position of a claw with high accuracy in the total stroke. SOLUTION: In a gripper comprising a driving part having a piston 4 reciprocated by fluid pressure and a slide unit having a master jaw adapted to open and close, a digital pulse output from light elements 10, 11 incorporated in the interior of the gripper is counted by an arithmetic function in a CPU, and converted to a unit of length according to the count value. Linear dimensional data converted to the unit of length can be used without setup replacement in the robot and transport line where many kinds of works are let flow by plural arbitrary dimensional data which can be stored by creating the storage area in the CPU.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid pressure gripping device having a function of detecting the position of a nail.

[0002]

2. Description of the Related Art In a conventional fluid pressure gripping device, a permanent magnet is mounted on a piston portion which reciprocates by fluid pressure in order to check the open end and closed end of a claw or to check the gripping of a work. A method of detecting and outputting the magnetic force of a permanent magnet mounted on a sensor using a sensor using a magnetoresistive element has been adopted.

[0003] When the conventional detection method described above is used in a transfer line that requires multiple types or a gripping device attached to the tip of a robot, it is necessary to adjust the position of the sensor every time the setup is changed. Needs considerable time.

As a method of eliminating the time for sensor adjustment at the time of setup change, a method such as using a plurality of sensors is used. However, a plurality of sensors are required, so that the cost is increased and a space for mounting the plurality of sensors is secured. Required.

Further, in the case of a conventional sensor using a magnetoresistive element, since the operating width of the sensor is wide, a long cylinder stroke is required to arrange a plurality of sensors, and the sensor is moved to a small gripping device having a short cylinder stroke. Can not be installed, there is a problem that the position of the sensor must be adjusted at the time of setup change, a lot of man-hours are required, and it is not suitable for high-precision detection by the sensor.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a gripping device used in a transfer device and a robot which are required to be used for various types, and which has a function capable of detecting a position of a nail with high accuracy in all strokes. By providing a device, an object of the present invention is to eliminate adjustment of a sensor at the time of changeover, to prevent trouble caused by improper adjustment, and to shorten the work time required for changeover.

[0007]

According to the present invention, there is provided a gripping device comprising a driving unit having a piston reciprocating by hydraulic pressure and a slide unit having a master jaw opening and closing. In, the light projection incorporated in the cylinder cover, by the light receiving sensor, the sliding working plate connected via a rod to a piston that performs reciprocating operation by fluid pressure, subjected to the same sliding process as the working plate,
The incident oblique light generated by reciprocating motion following the piston in front of the fixed plate attached in the cylinder cover is output as a pulse signal, and the pulse signal is counted by the arithmetic function in the CPU. By converting the count number into length units, linear dimension data converted to length units can be output for all strokes, and the linearly output dimensional data and CPU A storage area is created, and a plurality of arbitrary dimension data that can be stored can be used without any changeover in a robot and a transfer line on which various kinds of works flow.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described.

This embodiment comprises a drive unit having a cylinder 3 and a slide unit having a conversion unit for converting a reciprocating motion of a piston 4 into an opening and closing motion of a pair of claws 1. The piston 4 is inserted into the cylinder 3. Then, reciprocating motion is performed by fluid pressure.

The reciprocating motion of the piston 4 is arranged so as to be symmetrical with respect to the piston 4 and is moved in parallel in a direction perpendicular to the reciprocating motion direction of the piston 4 by a cam 5 rotating about a fulcrum shaft 6. In the parallel hand having a pair of claws 1 arranged, a concave portion is formed in the axial direction of the piston 4, and the rod 7 is pressed into the center of the concave portion, and the piston 4 follows the end of the press-fit rod 7. Then, the operation plate 8 which has been subjected to the slip processing so as to perform the reciprocating operation is attached.

Further, a protection case A12, a seal 16, and a spacer 17 are combined with the rod 7 to prevent a malfunction due to grease or dust entering the sensor portion via the rod 7 during operation. Installed in Case B13.

The sensor unit section is composed of two pairs of light projecting elements 10 and a pair of light-receiving elements 10 arranged opposite to each other in which the fixed plates 9 of FIG. The sensor unit is installed between the light receiving elements 11, the sensor unit is inserted into an insertion hole formed in the center of the cylinder cover A <b> 14, sandwiched and fixed between the cylinder cover A <b> 14 and the cylinder cover B <b> 15, and the cylinder cover is attached to the cylinder 3.

As shown in FIG. 3, the light emitting element 10 and the light receiving element 11 each consist of two (four in total), and are mounted at positions shifted by 1/4 pitch similarly to the fixing plate 9 on the light emitting element side. .

The fixed plate 9 shifts by 1/4 pitch and also has an effect of preventing the light source from spreading.

By shifting the position of the light emitting element 10, the output pulse waveform is output with the input 1 and input 2 shifted as shown in FIG.

The rising edge of the input 1 and the input 2 results in a pulse waveform as shown in FIGS. 5A and 5B, and the internal counter counts UP or DOWN.

The number of pulses, which is taken into the internal counter, is subjected to arithmetic processing in the CPU and converted into dimension data.

The arithmetic processing in the CPU performs the arithmetic operation in accordance with the operation of the hand and can always output as linear data. Further, the error caused by the claw shape can be converted into accurate dimensional data by correcting the arithmetic processing. .

As a method of output from the CPU to the outside, N is compared with data storage NO and outputs a matched NO.
Select and use the O output method and the method of outputting the internal dimension data as hexadecimal BIN type data.

In this embodiment, the parallel hand has been described. However, the present invention is not limited to the parallel hand alone, but may be applied to all devices in which the driving unit performs a linear motion, such as a fulcrum hand, a chuck, a slide unit, and a cylinder. Can be deployed.

[0021]

According to the present invention, highly accurate and linear position detection can be performed within the entire stroke of the claw.
In addition, a storage area is provided in the CPU to provide a gripping device capable of storing a plurality of arbitrary dimension data, so that in a robot and a transfer device that need to be used for a variety of types, dimension data corresponding to a plurality of workpieces is stored in the CPU. By doing so, it is possible to respond to each work without changing the work like the type using the conventional magnetoresistive element at the time of changing the work, so that the man-hour required for the changeover and the time are shortened Can do things.

Further, in the conventional gripping device, the operating end can only be confirmed by a sensor using a magnetoresistive element or the like. However, the gripping device according to the present invention can convert linear data into units of length in the CPU, and achieve high precision by gripping the work with claws. Since dimensional measurement and workpiece discrimination are possible, there is no need to provide a device for measurement and discrimination, and the device can be reduced in size and cost.

The recess provided in the piston has a structure that overlaps with a protective case projecting from a cylinder cover provided to prevent dust and the like from entering the sensor through the rod, thereby preventing interference during piston operation. This makes it possible to reduce the size of the apparatus.

[Brief description of the drawings]

FIG. 1 is a partial sectional view of a gripping device.

FIG. 2 shows a fixing plate according to the present embodiment.

FIG. 3 is an explanatory diagram showing the arrangement of sensors and plates.

FIG. 4 is an explanatory diagram showing a data output path.

FIG. 5 is an explanatory diagram showing a pulse waveform at the time of output.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Claw 2 Body 3 Cylinder 4 Piston 5 Cam 6 Support shaft 7 Rod 8 Operating plate 9 Fixing plate 10 Light emitting element 11 Light receiving element 12 Protective case A 13 Protective case B 14 Cylinder cover A 15 Cylinder cover B 16 Seal 17 Spacer

Claims (4)

[Claims] In a gripping device having a driving unit having a piston reciprocating by a fluid pressure and a pair of master jaws reciprocating by a reciprocating motion of the piston, a digital signal output from an optical element incorporated in the gripping device. A gripping device with a position detecting function, which is capable of detecting a nail position with high accuracy based on a pulse and storing nail position data. 2. An operating plate, which is connected to a piston which reciprocates by fluid pressure via a rod by a light emitting element and an optical receiving element arranged in a cylinder cover so as to face each other through a rod, is provided with an operating plate similar to the operating slide. Sliding processing is performed, and the incident light oblique light generated by reciprocating following the piston in front of the fixed plate attached in the cylinder cover is converted into a pulse signal, and the pulse signal is counted by the arithmetic function of the CPU, and the number of pulses is counted. 2. The gripping device with a claw position detecting function according to claim 1, wherein the conversion into the unit of length based on the count number of the counter is possible in all strokes of the gripping device. 3. A data storage area is created in the CPU, and a plurality of dimension data can be stored. The input data to the CPU is compared with the stored data, and the matched data is stored in the CPU. 2. The gripping device according to claim 1, wherein the gripping device can output to a device. 4. The gripping device according to claim 1, wherein the piston has a concave portion.