JP2000027951A - Slide clamper for shaft body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a slide clamper for a shaft body to exhibit a strong clamp force similar to that of a ball chuck for a wire. SOLUTION: The inclination angle θ of a taper surface 8, circumscribing with a ball 3, with the central axis of a case is set o 5-8 deg., and a higher clamp force is exhibited as the slide stroke of a holder 2 during clamping is suppressed. Namely, the number of using balls 3 is set to five and when a shaft body 6 is clamped, a part of the balls 3 are prevented from floating and separating from the peripheral surface of the shaft body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ball chuck type slide clamper which can clamp and fix a shaft at an arbitrary axial position.

[0002]

2. Description of the Related Art A slide clamper of this type is known from Japanese Utility Model Registration No. 2532576. Further, the present applicant has previously proposed a slide clamper in which a ball holding structure is improved (Japanese Patent Application No. 8-3582).
No. 50).

[0003]

In the conventional slide clamper which clamps a shaft body, a ball chuck for a wire is used as it is as far as the present inventor knows.
However, it is known that when a shaft is clamped by a wire ball chuck, the clamping force is lower than when the wire is clamped by the same ball chuck. According to the load-bearing test performed by the present inventors, it has been confirmed that the load-bearing capacity of the former is sufficiently smaller than the load-bearing capacity of the latter.

[0004] The clamping force of the ball chuck is determined by the frictional force between the ball and the object to be clamped. When the frictional force is constant, the angle of the tapered surface circumscribing the ball and the use of the ball are determined. It depends on the number. Therefore, if the load acting between the ball chuck and the object to be clamped is constant, and the angle of the tapered surface circumscribing the ball and the number of balls used are constant, the same clamping force should be exerted on the object to be clamped. It is. Nevertheless, it is considered that the reason why the clamping force of the ball chuck differs depending on the object to be clamped as described above is that the frictional force based on the difference in the surface structure between the wire and the shaft is different. While the ball surface at the time of clamping bites into the wire peripheral surface in a state where its cross-sectional shape is deformed, it only contacts the shaft body in a point contact manner, and this contact area The difference is considered to be the main factor of the difference in the clamping force.

Accordingly, the present inventors have attempted to develop a slide clamper that can exert a clamping force equivalent to that of a ball chuck for a wire. Basically, the smaller the angle of inclination of the tapered surface circumscribing the ball with respect to the axis center,
The ball can be pressed with stronger wedge force to increase the clamping force. However, reducing the angle of the tapered surface increases the axial stroke of the ball holder required for the ball to clamp the shaft. As a result, it becomes difficult to accurately position the clamp position of the slide clamper. In the conventional ball chuck for wires, the angle of the tapered surface is set to 10 to 12 degrees, and the number of balls used is often an arbitrary number within the range of 3 to 8.

[0006] The inventor prototyped several slide clampers having different angles of the tapered surface, and measured the load resistance of each slide clamper. Further, the number of balls used was changed variously for each slide clamp, and the load resistance was measured in the same manner. As a result of such trial and error, a slide clamper capable of exerting a clamping force equivalent to that of a wire ball chuck was successfully developed, and the present invention was proposed.

SUMMARY OF THE INVENTION An object of the present invention is to provide a slide clamper for a shaft body which can exert a stronger clamping force and therefore has a large load bearing capacity.

[0008]

As shown in FIGS. 1 and 2, a slide clamper according to the present invention comprises a cylindrical case 1 having a tapered surface 8 on one side of an inner surface thereof, and an axial through hole penetrating in an axial direction. And a holder 2 that movably supports the ball 3 in a direction crossing the shaft through hole 11. The holder 2 is mounted inside the case 1 so as to be movable in the axial direction, and is biased by a spring 5 toward the tapered surface 8.
The inclination angle θ of the tapered surface 8 with respect to the case center axis is 5
It is characterized in that it is set to about 8 degrees, and that the number of balls 3 held in the holder 2 is set to an odd number of 3 to 7.

Specifically, the holder 2 is provided with a cylindrical shaft portion 13 projecting from one side end of the case 1 to the outside of the case. It is screwed into the cylindrical shaft 13 in a state of contacting the side end of the case 1,
A lock screw 20 for pulling the holder 2 toward the side approaching the tapered surface 8 is provided at a side end of the case 1.

A spring receiving cylinder 4 for receiving one end of the spring 5 is screwed into the case 1 and mounted. A mounting bracket 24 for fixing the slide clamper to the mounting target is screwed into the spring receiving tube 4 and fixed.

[0011]

The inclination angle .theta. Of the tapered surface is set to 5 to 8 degrees. When the inclination angle .theta. Is less than 5 degrees, the axial stroke of the holder 2 at the time of clamping increases, and the slide clamp clamps the shaft 6 against the shaft 6. This is because it is difficult to accurately determine the position. When the inclination angle θ exceeds 8 degrees, the tapered surface 8 that pushes the ball 3 in the axial direction is used.
Is insufficient, and the required clamping force cannot be obtained.

The reason why the number of balls 3 incorporated in the holder 2 is specified to be an odd number of 3 to 7 is that when the number of loaded balls 3 is an even number, the pair of balls 3 One of the directly facing balls 3 may not be able to sufficiently pinch the shaft body 6 due to variations in the processing of the tapered surface 8 and the balls 3. This is for preventing the occurrence of the force and appropriately exerting the clamping force. Of course,
When the number of the balls 3 is less than three, the clamping force decreases. If the number of the balls 3 exceeds 7, processing of the holding holes 12 for the balls 3 provided in the boulder 2 becomes troublesome, and the labor for assembling the balls 3 increases. Holder 2
If the diameter of the ball 3 is constant, it is necessary to reduce the diameter of the ball 3 according to the increase in the number of balls.

[0013]

1 to 4 show the most preferred embodiment of a slide clamper according to the present invention. 2 and 3, the slide clamper is housed in a cylindrical case 1,
The holder 2 is movably accommodated along the axis, and five balls (steel balls) 3 are held by the holder 2. A spring receiving cylinder 4 is screwed into the right end of the case 1, and a compression coil type spring 5 for urging the holder 2 to move leftward in the drawing is interposed between the spring receiving cylinder 4 and the holder 2. Is done. Code 6
Is a shaft composed of a round shaft.

The case 1 is made of a machined product made of carbon steel for machine structural use, has a through hole 7 for the holder 2 on the left end thereof, and a small hole facing the side of the through hole 7 on the inner surface of the case. A round tapered surface 8 is formed, and a female screw 9 for the spring receiving cylinder 4 is formed adjacent to the large diameter end of the tapered surface 8. Tapered surface 8
Circumscribes each ball 3 and moves the ball 3 in the axial direction.

The holder 2 is made of a machined material of the same material as the case 1 and has a shaft through hole 11 for receiving the shaft body 6 along the axis thereof.
Is formed through. A shaft part having a larger diameter than the other is provided on the peripheral surface near the right end of the holder 2, and holding holes 12 orthogonal to the shaft through hole 11 are formed in the shaft part at equal intervals in the circumferential direction. A lock screw 20 described later is provided on the peripheral surface of the cylindrical shaft portion 13 on the left side of the shaft portion.
Screw 14 is formed. In order to prevent the ball 3 loaded in the holding hole 12 from dropping into the shaft through hole 11, the holding hole 1
The diameter of the inner opening 2 is set smaller than the diameter of the ball 3 (see FIG. 1).

The spring receiving cylinder 4 is formed of a cylindrical workpiece having both ends open, and has a screw 16 screwed into the female screw 9 on the left side of the peripheral surface thereof. A step 17 for receiving one end of the spring 5 is provided on the inner surface of the cylinder, and a female screw 18 for a mounting bracket 24 described later is formed on the right side of the step 17. As shown in FIG. 3, an engaging surface 19 for engaging a screwing tool is formed in parallel on the right end side of the peripheral surface of the spring receiving cylinder 4.

After the holder 2 loaded with the balls 3 is loaded into the case 1, one end of a spring 5 is fitted to the holder 2 and the spring receiving cylinder 4 is screwed into the case 1 so that the holder 2 has a tapered surface. 8 can be moved and biased. In this assembled state, the cylindrical shaft portion 13 projects from the outer surface of the case 1 through the opening 7.

As shown in FIG. 1, by inserting the shaft 6 into the shaft through hole 11 from the protruding end side of the cylindrical shaft portion 13, the insertion start end of the shaft 6 contacts the ball 3 exposed in the shaft through hole 11. Hit. When the shaft body 6 is further inserted, the holder 2
To the right against the urging force of. Accordingly, the ball 3 can move radially outward, and the shaft body 6 can pass through the space between the balls 3 and pass through the spring receiving cylinder 4.
When the insertion operation of the shaft 6 is stopped in this state, the holder 2 is pushed by the spring 5 and moves leftward. Therefore, a group of balls 3 is pressed by the tapered surface 8 and clamps and fixes the shaft body 6 cooperatively.

The clamping force by the ball 3 is further strengthened,
Further, in order to prevent the shaft body 6 and the holder 2 from moving relative to each other in a direction to release the clamping force due to an external vibration or the like, a lock screw 20 provided on the cylindrical shaft portion 13 is provided.
Screwed in. The lock screw 20 is formed of a cylindrical body having a female screw 21 formed on the inner surface, and has a through-hole 22 at the end of the cylinder that allows the shaft body 6 to enter and exit. An engaging surface 23 (see FIG. 3) for engaging a screwing tool is formed in parallel with the cylindrical peripheral surface.

When the lock screw 20 is screwed into the cylindrical shaft portion 13, its side end is received by the side end of the case 1 on the side of the opening 7. Therefore, when the lock screw 20 is firmly tightened, the holder 2 is pulled toward the lock screw 20 side, and the wedge force of the tapered surface 8 can be more firmly applied to the shaft 6 via the ball 3. In FIG. 2, reference numeral 24 denotes a slide clamper for a wall surface, a ceiling,
It is a mounting bracket for fixing to a mounting object such as a frame.

In order to minimize the sliding stroke of the holder 2 during clamping while fixing the shaft body 6 with a stronger clamping force, the inclination angle θ of the tapered surface 8 with respect to the center axis of the case is set to 6.5 degrees. In addition, as described above, the number of balls 3 loaded into the holder 2 is set to five, so that the ball diameter is prevented from decreasing.

In addition to the above-described embodiment, the angle θ can be arbitrarily selected within a range from 5 degrees to 8 degrees. The number of loaded balls 3 may be three or seven, but preferably three to five. The shaft body 6 may be a shaft body having a regular pentagonal cross section or a shaft body having a regular heptagonal cross section, depending on the number of balls 3 loaded.

[0023]

According to the present invention, the inclination angle θ of the tapered surface 8 is
Is set to 5 to 8 degrees so that the wedge force applied to the ball 3 by the tapered surface 8 can be enhanced while suppressing the slide stroke of the holder 2 during clamping. Furthermore, the number of balls 3 to be used is set to an odd number of 3 to 7, and it is possible to reliably prevent some of the balls 3 from floating from the peripheral surface of the shaft body 6 due to variations in the processing of the tapered surface 8 and the like. I did it. This makes it possible to obtain a slide clamper for a shaft having a large load-bearing force, capable of exhibiting a strong clamping force equivalent to that of a ball chuck for a wire.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a joint structure between a ball and a tapered surface.

FIG. 2 is a longitudinal sectional view of a slide clamper.

FIG. 3 is an exploded front view of the slide clamper.

FIG. 4 is a sectional view taken along line AA in FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Case 2 Holder 3 Ball 4 Spring receiving cylinder 5 Spring 6 Shaft 8 Tapered surface 20 Lock screw

Claims (3)

[Claims] 1. A cylindrical case 1 having a tapered surface 8 on one side of an inner surface, and a shaft through hole 11 penetrating in an axial direction, and movably supporting the ball 3 in a direction intersecting with the shaft through hole 11. A slide clamper which is mounted inside the case 1 so as to be movable in the axial direction, and is urged to move toward the tapered surface 8 by the spring 5; 8 with respect to the case center axis is 5
-8 degrees, and the number of balls 3 held in the holder 2 is 3-7
A slide clamper for a shaft body set to an odd number. The holder 2 is provided with a cylindrical shaft portion 13 protruding from one side end of the case 1 to the outside of the case, and is screwed into the cylindrical shaft portion 13 in contact with the side end of the case 1. The slide clamper for a shaft according to claim 1, wherein a lock screw (20) for pulling the holder (2) toward the side approaching the tapered surface (8) is provided at a side end of the case (1). 3. A spring receiving cylinder 4 for receiving one end of a spring 5 is screwed and mounted on the case 1, and a mounting bracket 24 for fixing the slide clamper to a mounting object is screwed and fixed on the spring receiving cylinder 4. Item 3. A slide clamper for a shaft body according to item 1 or 2.