JPS6346172Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a chuck used for machine tools, particularly those that require large machining torque such as lathes.

Conventional chucks of this type have three or four jaws attached to the front of the chuck body fixed to the main shaft of a lathe, etc., so that they can move forward and backward, and each jaw can be moved forward and backward simultaneously or separately by manual or hydraulic drive means. This allows the machine to grasp the workpiece.

In such chucks, each jaw is pressed against the outer periphery of the workpiece to grasp it, but if a part of the workpiece has been machined, the machined surface is used as a reference for grasping. There is a need to.

If this machined surface is, for example, a flange surface, and this surface is to be grasped perpendicularly to the rotational axis of the chuck body, conventionally, the front surface of the chuck body is
A method is used in which a plurality of positioning pieces that receive flanges of the workpiece are fixed, and the outer periphery of the workpiece is gripped by each pawl while the flanges are crimped onto the positioning pieces.

However, when tightening the claws, there are cases where a gap is created between the positioning piece and the flange, making it impossible to grip the workpiece correctly.In such cases, hit the workpiece with a wooden hammer, etc. It is necessary to keep it in close contact with the Therefore, it is very time-consuming and there is a risk of scratches on the processed surface.

For this purpose, a workpiece grasping member that can move within a certain range in the front-back direction and the inside-outside direction is provided at the inner end of the plurality of claws arranged on the front surface of the chuck body, respectively.
A support surface that slidably supports the outer surface of each grasping member is provided at the front of each claw, and the outer surface of each grasping member and its support surface are inclined so that the front end is closer to the inside. are known.

However, in the above-mentioned known method, in order to move the grasping member relative to the claw, a radial bolt provided on the grasping member support surface of the claw is fitted into a radial hole of the grasping member with play. The grasping member is pushed forward by the leaf spring.

In the case of the above-mentioned conventional example, since the bolt fixed to the support surface of the claw is only loosely fitted into the gripping member, the gripping member cannot be positioned at a specified location on the inclined support surface of the claw. Therefore, each gripping member cannot be at a fixed distance from the center of rotation of the chuck. For this reason, there is a drawback that concentric accuracy cannot be obtained with respect to the centripetal action required of most chucks other than the compensating chuck that provides center support.

The purpose of this invention is to solve the above-mentioned drawbacks of the conventional chuck and to provide a chuck with a large machining torque and high concentric accuracy.

In order to achieve the above object, this invention has a collar attached to the outside of each bolt attached at right angles to the front of a number of claws provided on the front surface of the chuck body, with some clearance left, and the collar is passed through a hole in the gripping member with some clearance left, a washer is fitted between the head of the bolt and the outer end of the collar, and a seat plate made of soft elastic material such as urethane rubber is fitted on the outside of the collar between the washer and the outer surface of the gripping member to seal the front of the gap between the bolt, collar, and gripping member,
The rear of the gap is closed by a soft elastic seat plate made of urethane rubber or the like that is fitted to the outside of the collar between the rear of the gripping member and the front of the claw.

The details of the chuck of this invention will be explained below based on an embodiment shown in the accompanying drawings.

In the figure, 1 is a chuck body fixed to the main shaft of a lathe (not shown). Reference numeral 2 denotes a plurality of reciprocating members that are fitted into a plurality of (three in the illustrated example) guide grooves provided radially in the main body 1 so as to be freely retractable.
A claw 3 is fixed to the front surface of each member 2 by bolts or the like.

Reference numeral 4 denotes a workpiece grasping member disposed near the inner front part of each claw 3, and this member 4 is attached by a bolt 5 screwed into the claw 3 so as to be movable within a certain range in the front-rear direction and the inner-outer direction.

That is, the collar 6 is fitted on the outside of the bolt 5 with some play, and the collar 6 passes through the hole in the member 4 with some play.

The head 7 of the bolt 5 is fitted in a recess 8 on the front side of the member 4, and a washer 9 and a seat plate 10 made of soft elastic material such as urethane rubber are sequentially placed on the outside of the collar 6 protruding into the recess 8. A washer 11 is fitted between the outer end of the collar 6 and the head 7.

Further, a seat plate 12 made of soft elastic material such as urethane rubber is fitted between the rear surface of the member 4 and the claw 3, and a collar 6 is fitted into a hole in the center of the seat plate 12.

The front portion of each pawl 3 is made to protrude forward, and the portion of this protrusion that faces the grasping member 4 is attached to a support surface 15.
and this support surface 15 and the grasping member 4 for this
The outer surface 16 of is inclined so that the front end is inward.

Reference numeral 18 denotes a plurality of positioning pieces fixed to the front surface of the main body 1 by bolts or other means, located between the respective claws 3, and extending from the front surface 19 of each piece 18 to the front surface 2 of the main body 1.
The distance to 0 is finished to exactly match each piece 18.

Reference numeral 21 in FIG. 1 is a cylindrical workpiece, and a machined flange 22 is provided at the front end of the workpiece.

Now, as shown in FIG. 1, the workpiece 21 is lightly gripped by the grasping member 4 of each claw 3, and the flange 22 is applied to the front surface 19 of each positioning piece 18.

Then, when each claw 3 is moved inward by a drive means (not shown), each grasping member 4 is pressed against the outside of the workpiece 21.

When each claw 3 is further moved in the direction of the workpiece 21 in this state, slippage occurs between the support surface 15 and the outer surface 16, and each grasping member 4 retreats while compressing the seat plate 12.

Therefore, the workpiece 21 grasped by the grasping member 4 moves toward the main body 1, and the flange 22 is brought into close contact with the front surface 19 of each positioning piece 18 to be accurately positioned.

As described above, this device is provided with a workpiece grasping member that can move within a certain range in the front-rear direction and in the inner-outward direction at the front inner side of each claw, and supports the outer surface of each grasping member so as to be slidable. A support surface is provided at the front of each claw, and each outer surface and the support surface are inclined so that the front end is inward. The members are crimped against the workpiece, and the slanted outer surface of each gripping member slides along the sloping support surface of each jaw toward the chuck body, ensuring that the flange is firmly attached to the locating piece. In particular, when fitting a collar to the outside of each bolt that is installed perpendicularly to the front of each claw with a slight clearance, the collar should be inserted into the hole of the grasping member. A washer is fitted between the head of the bolt and the outer end of the collar, and a soft elastic material such as urethane rubber is placed on the outside of the collar between the washer and the outer surface of the gripping member. Fit the seat plate to seal the front part of the gap between the bolt, collar and gripping member,
The rear part of the above gap is closed with a seat plate made of soft elastic material such as urethane rubber fitted to the outside of the collar between the rear part of the grasping member and the front part of the claw, making it easy to manage the dimensions of the claw, grasping member, and collar. Can be done.

The grasping member can thus be located at a designated position on the inclined support surface of the pawl.

In addition, the moving distance of the gripping members that retreat in the direction of the claws when gripping can be correctly regulated by accurately molding the seat plate made of urethane rubber, etc., so each gripping member always stops rotating regardless of whether the workpiece is gripped or not. They are at the same distance and can easily achieve concentric accuracy.

Since the shape of the nail is simple, it can be used by simply modifying the standard raw nail.

Generally speaking, chucks used for cutting must take into account malfunctions caused by bits of debris being caught in the chuck, but in the case of the chuck of this invention, the seat plate and washer made of urethane rubber, etc. Since the gap between the collar insertion hole of the member and the gap between the rear surface of the grasping member and the claw are sealed, there is no risk of malfunction due to entry of chips or the like.

[Brief explanation of the drawing]

FIG. 1 is a partially longitudinal side view showing an embodiment of the chuck of this invention, and FIG. 2 is a front view of the same. DESCRIPTION OF SYMBOLS 1... Chuck body, 3... Claw, 4... Workpiece gripping member, 15... Support surface, 16... Outer surface.

Claims (1)

[Scope of utility model registration request] A plurality of claws are arranged radially on the front surface of the chuck body, and driving means for moving each claw back and forth is provided so that the workpiece is gripped by the inner end of each claw. A workpiece gripping member that can move within a certain range in the front-rear direction and the inside-outside direction is provided, and a support surface that slidably supports the outer surface of each gripping member is provided in the front part of each claw. The outer surface and support surface are made of a chuck that is inclined so that the front end is inward, and the collar is fitted with a slight clearance on the outside of each bolt that is installed perpendicularly to the front of each claw. , this collar is passed through the hole of the grasping member with some play,
A washer is fitted between the head of the bolt and the outer end of the collar, and a soft elastic seat plate made of urethane rubber is fitted on the outside of the collar between the washer and the outer surface of the gripping member, and the bolt, collar, and gripping member are fitted together. A chuck for a machine tool in which the front part of the gap between the two is closed, and the rear part of the gap is closed with a seat plate made of urethane rubber or other soft elastic material fitted to the outside of the collar between the rear part of the gripping member and the front part of the claw.