JP2002192433A - Pull stud mounting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pull stud mounting device capable of preventing the looseness of a pull stud. SOLUTION: A lock nut 20 having a male screw 21 on the outer periphery and a screw stem 11 of the pull stud 10 are put in screw engagement with a screw hole 5 formed in the small end face of a taper shank 2. The lock nut 20 is locked to the pull stud 10, reverse female screws 22, 15 are formed on the inner periphery of the lock nut 20 and on the inner periphery at the end of a through-hole 14 formed in the pull stud 10, and a fastening screw 40 having a reverse screw formed on the outer periphery is put in screw engagement with the female screws 15, 22. With the rotation of the fastening screw 40, the lock nut 20 is moved to the pull stud 10 in the axial direction to prevent the looseness of the pull stud 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a device for attaching a pull stud to an end of a tool shank or a shank formed on a tool holder.

[0002]

2. Description of the Related Art Generally, when a tool holder is mounted on a main shaft of a machining center, a taper shank of a tool holder is inserted into a taper hole formed in a front end surface of the main shaft, and a pull stud mounted on a small end surface of the taper shank. Is pinched by a chuck provided on the main shaft side to pull the pull stud so that the tapered surface on the outer periphery of the taper shank is in close contact with the inner periphery of the tapered hole. In the tool holder, the tapered surface on the outer periphery of the taper shank is in close contact with the inner periphery of the tapered hole, and the end surface of the flange provided on the large end surface side of the taper shank is in close contact with the end surface of the main shaft, thereby supporting the two-surface constraint. Some are said to be.

Conventionally, when a pull stud is attached to a taper shank, a screw hole 51 is formed in a small end surface of a taper shank 50 as shown in FIG.
Then, a screw shaft 53 provided on the pull stud 52 is screw-engaged to tighten the pull stud 52 until the flange 54 formed on the pull stud 52 comes into close contact with the small end face 55 of the tapered shank 50.

[0004]

As shown in FIG. 4, if the screw shaft 53 of the pull stud 52 is simply screw-engaged with the screw hole 51 of the taper shank 50 as shown in FIG. As a result, the pull stud 52 may be loosened.

Here, the pulling mechanism of the tool holder provided on the main shaft of the machining center draws the taper shank in the axial direction by utilizing the elasticity of a spring such as a disc spring. If the studs become loose, the pulling force (tightening force) changes,
Due to the change in the tightening force, the attachment of the tool holder becomes unstable, and it becomes impossible to perform highly accurate processing on the workpiece.

In order to prevent the pull stud from loosening, a loosening stopper made of synthetic resin is buried around the outer periphery of the screw shaft of the pull stud, and the loosening stopper is brought into close contact with the screw hole of the taper shank so that the frictional force of the screw hole against the screw is increased. However, there is an inconvenience that the elasticity of the anti-loosening piece gradually decreases due to the attachment and detachment of the pull stud, so that it cannot be used repeatedly.

SUMMARY OF THE INVENTION An object of the present invention is to provide a pull stud mounting device for a tool shank capable of reliably preventing the pull stud from being loosened and obtaining a stable mounting state on the tool shank.

[0008]

According to the present invention, there is provided a pull stud in which a screw shaft provided on a pull stud is threadedly engaged with a screw hole formed in a small end surface of a tapered shank. Wherein the lock nut having an external thread on its outer periphery is threadedly engaged with a screw hole formed in the taper shank, and detent means is provided between the lock nut and the pull stud. A female screw is provided on each of the inner circumferences of the distal ends of the axial through holes formed in the pull studs, and the female screw is a reverse screw. A configuration is employed in which the female screw is screw-engaged, and a wrench engaging portion is provided on the end face of the tightening screw on the pull stud side.

Here, as the detent means, a configuration is employed in which a detent pin is protruded on one of the opposing surfaces of the pull stud and the lock nut, and a pin insertion hole for inserting the detent pin is formed on the other. can do.

[0010] With the above configuration, a wrench is inserted into the through hole formed in the pull stud, and the wrench is engaged with the wrench engaging portion of the tightening screw to rotate the tightening screw. The lock nut moves in the axial direction with respect to the pull stud, and the external thread of the pull stud and the external thread of the lock nut come into close contact with the flank on the opposite side of the thread in the screw hole of the taper shank, and the close contact loosens the pull stud. Can be stopped.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. Figure 1 shows the tool holder 1
1 shows an example in which the pull stud 10 is attached.

The tool holder 1 has a tapered shank 2 inserted into a tapered hole a of a main shaft A, a flange 3 is formed on a large end face side of the tapered shank 2, and a tool B is formed on a distal end face side of the flange 3. The chuck 4 for detachably holding the chuck is provided.

A screw hole 5 is formed in the small end surface of the taper shank 2. The flange 3 is formed with a key groove 6 with which a drive key b provided on the front end surface of the main shaft A can be engaged.

As shown in FIG. 2, the pull stud 10
A screw shaft 11 is provided at a front end, a flange 12 is formed at a rear end of the screw shaft 11, and a grip portion 13 is provided at a rear end surface of the flange 12. The pull stud 10 is formed with an axial through hole 14 extending from the distal end surface of the screw shaft 11 to the rear end surface of the grip portion 13, and a female screw 15 is provided on the inner periphery of the distal end portion of the through hole 14.

A lock nut 20 having an external thread 21 on the outer periphery and a screw shaft 11 of the pull stud 10 are screw-engaged with the screw hole 5 of the tool holder 1, and between the screw shaft 11 and the opposing surface of the lock nut 20. A detent mechanism 30 is provided.

The detent mechanism 30 has a detent pin 31 protruding from the distal end surface of the screw shaft 11, and the detent pin 31 is inserted into a pin insertion hole 32 formed in the lock nut 20.

A lock pin may be provided on the lock nut 20 so as to protrude therefrom, and a pin insertion hole into which the lock pin is inserted may be formed on the distal end surface of the screw shaft 11.

A female screw 2 is provided on the inner periphery of the lock nut 20.
2 are formed. This female screw 22 is a pull stud 1
The female screw 15 formed on the inner periphery of the through hole 14 is a reverse screw.

The pull stud 10 and the lock nut 20 are connected in the axial direction by a tightening screw 40. Tightening screw 40
Has an external thread 41 threadedly engaged with the internal thread 15 of the pull stud 10 and an external thread 42 threadedly engaged with the internal thread 22 of the lock nut 20, and has wrench engagement portions 43 on both axial end faces. Are formed. Here, although a square hole is shown as the wrench engaging portion 43, the wrench engaging portion 43 is not limited to this. For example, it may be a square axis.

The pull stud mounting apparatus shown in the embodiment has the above-described structure. When mounting the pull stud, the pull stud 1 is engaged by the screw engagement of the tightening screw 40.
In the state where the lock nut 20 is connected to the tip of
A state in which the lock nut 20 and the screw shaft 11 of the pull stud 10 are screw-engaged with the screw hole 5 of the taper shank 2 with the lock nut 20 first, and the flange 12 of the pull stud 10 is in close contact with the small end face 7 of the taper shank 2. At
The tightening screw 40 is rotated.

When the tightening screw 40 rotates, the through hole 1
A wrench is inserted into the wrench 4, and the wrench is engaged with the wrench engaging portion 43 to apply a rotational force to the wrench.

When the tightening screw 40 is rotated by the wrench, the female screw 15 of the pull stud 10 and the female screw 22 of the lock nut 20 with which the tightening screw 40 is screwed are reverse screws. While rotating in the axial direction with respect to the pull stud 10 while rotating, the lock nut 20 moves in the direction opposite to the moving direction of the tightening screw 40.

The axial movement of the lock nut 20 causes
The external thread 21 formed on the outer periphery of the lock nut 20 and the external thread formed on the outer periphery of the screw shaft 11 of the pull stud 10 are in close contact with the flank of the threaded hole 5 formed in the tapered shank 2 on the opposite side of the thread. Pull stud 10
Is prevented from loosening.

When the pull stud 10 is removed, the tightening screw 40 is turned in the opposite direction to release the close contact between the male screw 22 of the lock nut 20 and the screw hole 5 of the tapered shank 2. Then, the pull stud 10 is rotated in the loosening direction.

Although the embodiment has been described by taking as an example the locking of the pull stud attached to the taper shank of the tool holder, the locking of the pull stud attached to the tool shank also employs the locking device shown in the embodiment. can do.

[0026]

As described above, according to the present invention, when the tightening screw is rotated, the lock nut moves in the axial direction with respect to the pull stud, and the external thread of the lock nut and the outer circumference of the pull stud are rotated. Since the external thread is in close contact with the flank on the opposite side of the thread of the screw hole formed in the tapered shank, the pull stud can be reliably prevented from loosening, and since the loosening stop is due to the screw mechanism, repeated Can be used.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view showing an embodiment of a pull stud mounting device according to the present invention.

FIG. 2 is an enlarged sectional view showing a main part of FIG. 1;

FIG. 3 is an exploded perspective view showing a part of a pull stud, a tightening screw and a lock nut.

FIG. 4 is a partially cutaway front view showing a conventional pull stud mounting device.

[Explanation of symbols]

 2 Taper shank 5 Screw hole 10 Pull stud 11 Screw shaft 14 Through hole 15 Female screw 20 Lock nut 21 Male screw 22 Female screw 30 Detent mechanism 31 Detent pin 32 Pin insertion hole 40 Tightening screw 41, 42 Male screw 43 Wrench engaging part

Claims (2)

[Claims] 1. A pull stud mounting device in which a screw shaft provided on a pull stud is threadedly engaged with a screw hole formed on a small end surface of a tapered shank. The lock nut is screw-engaged, and detent means is provided between the lock nut and the pull stud, and the inner circumference of the lock nut and the inner circumference of the tip end of an axial through hole formed in the pull stud are respectively provided. Female screw, and the female screw is a reverse screw.The tightening screw with the reverse screw formed on the outer periphery is screw-engaged with the female screw of the pull stud and the female screw of the lock nut, and is attached to the end face of the pull screw on the pull stud side. An installation device for a pull stud, wherein a wrench engaging portion is provided. 2. The rotation-stopping means has a structure in which a rotation-stop pin is protruded on one of opposing surfaces of a pull stud and a lock nut, and a pin insertion hole for inserting the rotation-stop pin is formed on the other. The pull stud mounting device according to claim 1.