JPH11309764A - Screw tip detaching tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate detachment of a screw-tip without damaging it by a detaching tool having a plurality of setscrews, each of which reaches from the outer peripheral surface of a spanner head in the line grooves on the outer peripheral surface of a plunger so as to act as a dent. SOLUTION: A screw tip detaching tool 10 is attached to a screw tip. After that, the spherical parts at the tips of setscrews 15 are fitted into the line grooves of a screw plunger indicated with chain lines. Then, after being dented, the end part of a handle lever 14 is struck with a hammer in the direction indicated with the arrow C so as to detach the screw tip. Since the line grooves of the screw tip are threaded righthandedly and the setscrews 15 are fitted in the line grooves, even when the screw tip detaching tool 10 idles during the striking of the lever, the screw tip detaching tool 10 rotates along the line grooves and, at the same time, retreats to the direction of the axis line of a screw, resulting in abutting the tapered surface 11 in the inner diametral surface of a spanner head 13 against a plunger part so as not to allow to develop the further retreat of the tool and the damaging of the line grooves of the screw tip.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tool for removing a screw tip of an injection molding machine screw provided with a groove in a plunger portion.

[0002]

2. Description of the Related Art Referring to FIGS. 5 and 6, a conventional tool for removing a screw tip of a screw of an injection molding machine will be described. In order to increase the back pressure during injection molding of PVC resin, a groove is formed in a plunger portion of the screw tip. The screw tip provided is used. When removing this kind of screw tip from the screw body, the screw tip removing tool 1 is attached to the screw tip 6, and the bolt 3 is tightened by a wrench (not shown). Was tightened via a brass spacer 8, and the end of the handlebar 4 was hit with a hammer in the direction of arrow A (the screw tip was attached to the screw body with a left-hand screw) to remove it.

[0003]

However, the screw tip holding force of the screw tip removing tool 1 is due to the frictional force between the spacer 8 and the screw tip by tightening the bolts 2 and 3 at the screw tip portion. Therefore, it is an extremely unstable holding force, and although it is strongly tightened before hitting with the hammer, it gradually loosens due to the impact, and the screw rotates as it tightens the screw tip. It was tight and difficult to remove. In such a case, it is necessary to remove the spacer 7 provided between the screw 5 and the screw tip 6 by machining, which is not only a very troublesome operation but also sometimes damages the screw tip.

An object of the present invention is to solve the above-mentioned disadvantages and to provide a tool for removing a screw tip which can be easily removed without damaging the screw tip.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention provides a plunger for forming a small gap between the inner surface of a heating barrel having a groove on an outer peripheral surface thereof, and a conical portion following the plunger. In a tool for removing a screw tip of an injection molding machine screw comprising a tapered portion having a shape, a part of the inner diameter surface is a tapered surface fitted into the tapered portion,
The remaining portion is a cylindrical surface into which the outer peripheral surface of the plunger is fitted, and the outer peripheral surface is a polygonal or circular spanner head,
Removal of a screw tip of an injection molding machine screw having a handlebar attached to the wrench head and a plurality of setscrews reaching the inside of a groove of the plunger outer surface from the outer surface of the wrench head and stopping the rotation. Tool.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the present invention will be described with reference to FIGS. 1 to 4. Reference numeral 10 denotes a tool for removing a screw tip. A spanner head 13 having a hexagonal outer peripheral surface and a cylindrical surface 12 into which the outer peripheral surface of the plunger at the rear position of the taper portion is inserted.
And a handlebar 14 fixed to the spanner head 13
And a plurality of setscrews 15 which reach from the outer peripheral surface of the spanner head 13 into the grooves on the outer peripheral surface of the plunger and serve as a detent.
It consists of.

Here, the outer peripheral surface of the spanner head 13 is not limited to a hexagon as described above, but may be a polygon or a circle. Also, the plurality of setscrews 15 may be either headed or headless as shown in FIG. 4, and can be selected from those which do not hinder hitting or mounting. A spherical state that fits into the groove is desirable. Further, the illustrated wrench head 13 is configured so that six setscrews 15 are inserted from the outer peripheral surface, but it is not always necessary to use all of them and can be freely selected by the grooves of the plunger.

Since the screw tip is removed as described above, the screw tip removal tool 10 is attached to the screw tip, and the spherical portion at the tip of the set screw 15 is indicated by a chain line as shown in FIG. Then, the screw tip is removed by hitting the end of the handlebar 14 in the direction of arrow C with a hammer. Even if the screw tip removing tool 10 rotates idle without rotating the screw tip during hitting, the groove of the screw tip is provided with a right-hand thread, and the set screw 15 is fitted in the groove. Therefore, the screw tip removing tool 10 is retracted in the axial direction of the screw while rotating along the groove (rightward in the figure).
However, the tapered surface 11 of the inner diameter surface of the spanner head 13 abuts against the plunger portion and does not retreat any more, so that the screw tip groove is not damaged.

[0009]

As described above, the screw tip removing tool according to the present invention is very unstable because the screw tip holding force of the conventional device depends on the frictional force between the brass spacer and the screw tip. As compared with the case, there is a detent, the screw tip holding force is stable and the screw tip is not only reliably removed, but also the removal tool does not rotate the screw tip while hitting The screw tip groove will not be damaged even if the idle rotation occurs.

[Brief description of the drawings]

FIG. 1 is a front view of a screw tip removing tool showing one embodiment of the present invention.

FIG. 2 is a view of a tool for removing a screw tip showing one embodiment of the present invention, and a side view of FIG. 1;

FIG. 3 is a view of a tool for removing a screw tip, showing one embodiment of the present invention, and is a sectional view taken along line DD of FIG. 1;

FIG. 4 is a view showing a set screw used for a screw tip removing tool showing one embodiment of the present invention.

FIG. 5 is a front view showing a conventional screw tip removing tool.

FIG. 6 is a view showing a conventional screw tip removal tool;
FIG. 6 is a sectional view taken along line BB of FIG. 5.

[Explanation of symbols]

 Reference Signs List 10 Screw tip removal tool 11 Tapered surface 12 Cylindrical surface 13 Spanner head 14 Handlebar 15 Set screw

Claims (1)

[Claims] 1. A screw tip removal of an injection molding machine screw comprising a plunger forming a small gap between a heating barrel inner diameter surface having a groove on an outer peripheral surface and a conical tapered portion following a tip of the plunger. In the tool, a part of the inner diameter surface is a tapered surface that fits into the tapered portion, and the remaining part is a cylindrical surface that fits the outer peripheral surface of the plunger, and the outer peripheral surface is polygonal or circular. And a handlebar attached to the wrench head, and a plurality of setscrews that extend from the outer surface of the wrench head into the grooves on the outer surface of the plunger and serve as detents. Chip removal tool.