JP2009125821A - Clamping device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a clamping device surely detecting seating of a workpiece whose surface is not flat like a casting. <P>SOLUTION: In a state of the workpiece W being inserted between a pad member 12 and a clamper 5 (an unclamped state), air is blown off from an air blowoff port 21 because the pad member 12 is in a projected position, and the unclamped state is detected. A clamp cylinder 1 is then actuated to press the workpiece W to the tip seating surface 19 of the pad member 12 by the clamper 5. The pad member 12 thereby retreats against a spring 13 into a clamping position where a flange part 16 abuts on the front end face of an outer cylinder member 11. At this time, the air blowoff port 21 is blocked with the outer cylinder member 11, and a clamped state is detected. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a clamping device for fixing a workpiece between a workpiece cradle and a clamper.

  It is necessary to fix the workpiece when machining or assembling parts. As a device for fixing the workpiece, conventionally, a cylinder is driven to cause the clamper to move forward or backward, or to rotate, and the workpiece is fixed between the workpiece cradle.

  For example, Patent Document 1 discloses a state in which an air outlet is opened on a work placement surface of a work cradle, a magnet is provided on the work placement surface, and the work is attracted by the magnet, that is, the work is placed on the work placement surface. When seated, the air outlet is closed with a workpiece, the air flow is switched in the direction of the clamp cylinder, the clamp cylinder is operated, and the clamp cylinder is swung by the operation of the clamp cylinder, and the workpiece is placed between the workpiece mounting surface and the clamper. The content of clamping is disclosed.

  In Patent Document 2, an air passage connected to an air source for driving a clamp cylinder is formed in a clamp base, an air outlet opening connected to the air passage is opened on a work placement surface of the clamp base, and the work is placed on the clamp base. When set, the air outlet is blocked, and when this is detected, the air from the air source is supplied to the clamp cylinder, and the clamp cylinder is operated to move the workpiece between the clamp part and the work placement surface of the base. The contents to be clamped are disclosed.

JP 2000-354927 A JP 2005-046918 A

  When the clamp device disclosed in Patent Documents 1 and 2 is incorporated in a jig used in a machining center, the operation of the clamp cylinder is electrically confirmed by a limit switch or a sensor. For this reason, a detachable connector is required between the jig and the machining center, wiring is complicated, and a detection circuit is also required. Recently, a pneumatic clamp detection mechanism has been proposed, but a circuit separate from the seating detection is required.

  In the clamping devices disclosed in Patent Documents 1 and 2, an air blowing port is opened on the work placement surface of the work cradle (pedestal), and the air blowing port is closed with the work, thereby confirming seating. It is carried out. However, if the workpiece has fine irregularities on the surface as in the case of a casting, no matter how smooth the workpiece mounting surface is, the workpiece cannot completely block the air outlet, and seating confirmation cannot be performed. There is a case.

  In both Patent Documents 1 and 2, air for confirming seating and air for operating the clamp cylinder are common. For this reason, a hydraulic type cannot be used as a clamp cylinder, and an application range will be limited.

  Furthermore, both cited documents 1 and 2 have a configuration in which the clamp cylinder is operated after confirming the seating of the workpiece, and an operation delay is likely to occur.

  In order to solve the above problems, a clamping device according to the present invention is a clamping device that clamps a workpiece between a clamper and a workpiece cradle, wherein the workpiece cradle slides into an outer cylinder member and the outer cylinder member. A pad member that is arranged and urged in a protruding direction by a resilient member, and an air outlet is formed on the outer peripheral surface of the pad member, and the pad member is retracted to a normal clamping position. In this state, it is blocked by the outer cylinder member, and the pad member is opened to a position where it is detached from the outer cylinder member in a state of protruding to the unclamping position.

  The air outlet can be formed not only on the outer peripheral surface of the pad member, but also on the tip seating surface of the pad member to which the workpiece is pressed during clamping. By doing in this way, it is possible to detect not only the seating confirmation but also the seating abnormality that is clamped in a state in which the workpiece has fallen.

According to the clamping device of the present invention, the seating confirmation and the clamping cylinder operation confirmation can be simultaneously performed using one pneumatic work cradle. Therefore, the electric limit switch and sensor for confirming the operation of the conventional clamp cylinder can be omitted.
In addition, according to the clamping device of the present invention, seating confirmation can be reliably performed even when there is unevenness on the workpiece surface as in a casting.
Further, according to the present invention, since the fluid for confirming the seating and the fluid for operating the clamp cylinder are not related, a powerful hydraulic type can be used as the clamp cylinder, and the application range is widened.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an overall configuration diagram of a clamping device according to the present invention, FIG. 2 is an enlarged sectional view of a work receiving base constituting the clamping device, FIG. 3 is a sectional view of the clamping device in an unclamped state, and FIG. It is sectional drawing of the clamp state of an apparatus.

  The clamping device comprises a clamp cylinder 1 and a work cradle 10 fixed to a common base. Pipes 2 and 3 for supplying and discharging a working fluid such as oil and air are connected to the clamp cylinder 1, and a clamper 5 is attached to a piston rod 4 that expands and contracts by supplying and discharging the working fluid.

  On the other hand, the work cradle 10 includes an outer cylinder member 11 and a rod-shaped pad member 12 slidably disposed in the outer cylinder member 11, and an elastic member in which the pad member 12 is disposed in the outer cylinder member 11. It is urged in the protruding direction by a generating member (spring) 13.

In addition, the protrusion limit of the pad member 12 is regulated by the stopper 14 attached to the outer cylinder member 11 coming into contact with one end of the groove 15 formed in the length direction of the outer peripheral surface of the outer cylinder member 11,
The protrusion limit of the pad member 12 is regulated by the flange portion 16 formed on the pad member 12 coming into contact with the front end surface of the outer cylinder member 11.

  An air passage 17 is formed at the base of the outer cylinder member 11, and an air passage 18 is formed in the pad member 12 in the axial direction. The air passage 17 and the air passage 18 communicate with each other via the storage space of the spring 13. The air passage 18 is closed at the opening formed in the front seating surface 19 of the pad member 12 by a blind plug 20, and the pad member 12. An air outlet 21 connected to the air passage 18 is opened at a portion close to the flange portion 16.

  The opening position of the air ejection port 21 is determined by the outer cylinder member 11 in a state where the pad member 12 is retracted to a normal clamping position, that is, in a state where the flange portion 16 is retracted to a position where the flange portion 16 is in contact with the front end surface of the outer cylinder member 11. When the pad member 12 is closed and protrudes to the unclamping position, that is, when the pad member 12 is in the forward limit by the stopper 14, the pad member 12 is opened.

  In the above, when the workpiece W is inserted between the pad member 12 and the clamper 5 (unclamped state), as shown in FIG. 3, since the pad member 12 is in the protruding position, air is ejected from the air ejection port 21. Detecting the unclamped state.

  Next, the clamp cylinder 1 is operated and the workpiece W is pressed against the tip seating surface 19 of the pad member 12 by the clamper 5. Then, as shown in FIG. 4, the pad member 12 moves back to the clamp position where the flange portion 16 abuts against the front end surface of the outer cylinder member 11 against the spring 13. At this time, it is detected that the air jet port 21 is closed by the outer cylinder member 11 and is in a clamped state.

  FIG. 5 shows a clamping device according to another embodiment. In this embodiment, an air jet port 22 is also opened at the tip seating surface 19 of the pad member 12.

  Since the air ejection port 22 is open, in the unclamped state shown in FIG. 5A, air is ejected from both the air ejection ports 21 and 22, but as shown in FIG. Is clamped diagonally, if the opening of the tip seating surface 19 is closed as in the first embodiment, it is determined that the clamp has been normally performed. It is also possible to detect such abnormal seating.

Overall configuration diagram of a clamping device according to the present invention Enlarged cross-sectional view of workpiece cradle constituting the clamping device Sectional view of the clamping device in an unclamped state Cross-sectional view of the clamp device in the clamped state (A) is sectional drawing of the unclamped state of the clamp apparatus which concerns on another Example, (b) is sectional drawing explaining the state of seating abnormality

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Clamp cylinder, 2, 3 ... Piping, 4 ... Piston rod, 5 ... Clamper, 10 ... Work receiving base, 11 ... Outer cylinder member, 12 ... Pad member, 13 ... Spring member (spring), 14 ... Stopper, DESCRIPTION OF SYMBOLS 15 ... Groove, 16 ... Flange part, 17, 18 ... Air channel | path, 19 ... The tip seating surface of a pad member, 20 ... Blown plug, 21, 22 ... Air outlet, W ... Workpiece | work.

Claims (2)

In a clamp device that moves a clamper by operation of a cylinder and clamps a workpiece between the clamper and a workpiece cradle, the workpiece cradle is disposed in an outer cylinder member and is slidably disposed in the outer cylinder member. A pad member that is biased in the protruding direction by the emitting member, and an air outlet is formed on the outer peripheral surface of the pad member. A clamping device, wherein the clamping device is closed by a cylindrical member and opens to a position where the pad member protrudes to an unclamping position and is detached from the outer cylindrical member. 2. The clamping device according to claim 1, wherein an air outlet is also opened at a tip seating surface of a pad member to which a workpiece is pressed during clamping.

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