JPS5988264A - Mechanism of preventing slip-off of steel ball of impact wrench - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mechanism for preventing steel balls from falling off in impact wrenches, etc., which moves a direct cutting cam and a steel ball hammer forward and backward.

Let me explain the fins using an impact wrench as an example. As shown in Figure 1, the hammer is a sliding part on the outer diameter of the spring seat.
It moves forward and backward along the leads of both cams, which are provided with 1U cuts on the spindle and hammer.

According to the prior art, the maximum amount of retraction of the sliding hammer was regulated at the position where the steel ball (B) reached the end points of both cams. Therefore, since the hammer is repelled via the steel ball (B) at the end position of the cam, a state occurs where the steel ball (B) does not receive any force from the compression spring momentarily.

Since the hammer does not follow the lead of the cam and tries to move forward only by the replacement force of the compression spring, the steel ball (B) that is free in the cam pops out from the end face of the normal cam. was there.

Steel ball (B) was caught between the hammer and the case, causing failures such as damage to the hammer case and damage to the hammer claw.

Furthermore, as shown in Figure 2, the steel ball (B) protrudes a distance A from the end face of the hammer cam at the maximum retracted position of the hammer, and Being able to insert from any position,
This was a factor that increased the chances of the steel ball (B) flying out.

An object of the present invention is to provide an inexpensive and reliable device for preventing steel balls from falling off in this type of hammer striking mechanism.

According to the present invention, when the retraction amount of the hammer is regulated at the end point of the cam, the hammer rebounds and the steel ball (B) is no longer subjected to the force of the compression spring, so it becomes free, and the rollers in the cam are no longer able to move, and the hammer cam Focusing on the fact that the steel ball (B) can be inserted from any position on the end face of the hammer cam, there is a greater chance that the steel ball (T3) will pop out from the end face of the hammer. The maximum retracted position is regulated by the spring seat end face and the hammer inner diameter stepped part, and... is provided at the end face of the knob cam.
The shape of the Hough 7 spring seat, the length of the hammer cam and spindle cam, and the relationship between the compression springs have been devised.

An embodiment according to the present invention will be described below.

As shown in FIGS. 1, 3, 4, 5, 6, and 7, the steel ball fall prevention mechanism t of the Innovac wrench according to the present invention is mounted directly on the spindle 1 and the spindle 1. A cut spindle cam 2, a hammer 3 with rotational inertia for hitting Albil, a hammer cam 4 cut directly into the hammer, a spring seat 6 that provides sliding support for C/73, and rotation of the spring seat 6. A steel ball (A) 5 that provides rotational compression and rotational restoring force to the compression spring 10, a spring seat end surface 7 and a 7-inch internal diameter stepped portion 8 that restricts the backward movement of the hammer 3, and a spindle cam 2.
Steel ball (B) 9 interposed in Tono Tsumakam 4
, No.3 K compression spring 10 for giving rotational energy key, receiving the impact energy from the No.3 K, anvil 11 for tightening the bolt, no. No.3 case 12 for protecting the impact mechanism, meshing with the anvil 11 to rotate. /% clutch pawl 13, steel ball (B
) into which the groove 14 is inserted.

In the above configuration, the hammer 3 reaches a certain tightening torque.
The dimensions are determined so that the amount of retraction when the anvil 11 retreats while disengaging from the claw portion of the anvil 11 is always regulated at the position where the tin 1J sheet end surface 7 and the inner diameter stepped portion 8 of the anvil 11 are in contact with each other. There is. Therefore, in this state, the steel ball (B) 9 is always located on the near side of the end point of the mutual cam trajectory, and the compression spring 10 is also dimensioned so as not to be fully compressed.

The reason why the hammer retraction amount is regulated by the spring seat end surface 7 and the hammer inner diameter stepped portion 8 is that the repulsion in the radial direction when the hammer 3 retreats and collides with the hammer 3 is smaller than when cam regulation is used. (B) The time for 9 to become free without receiving the force of compression nail 10 in the cam is short, and the chance of it falling off is lower;
This decision was made based on the fact that if the total compression dimension is used, the vibration in the thrust direction will increase and the working conditions will deteriorate.

Furthermore, as shown in Fig. 3, when the no. 3 is retracted to the maximum, the steel ball (B) is dimensioned so that it has a concave leaf from the end face 16 of the no. cam. (B) By making the distance 8 dimension to the 9 end face as long as possible, the chance of it popping out is lowered.

Next, the assembly of the steel ball (B) 9 will be explained.

As shown in FIG. 1, a spring seat 6 is arranged at the base of the spindle 1 via a large number of steel balls (A), a compression spring 10 is placed on the inner diameter of the spring seat 6, and a nozzle is placed on top of it. Place knob 3.

Then, the upper end of the hammer clutch pawl 13 is forcibly moved back in the axial direction using a press or the like, and is pressed to a position where the spring seat end surface 7 contacts the hammer inner diameter stepped portion 8. This state is shown in FIGS. 6 and 7.

In FIG. 6, a groove 14 provided in the hammer cam end face 16
The steel ball (B) 9 is inserted and assembled from the space A15a formed by the spindle cam 4. Therefore, as shown in FIG. 7, the space B15bK formed by the hammer cam one end surface 16 and the spindle cam 2 is dimensioned so that the steel ball (B) 9 cannot be inserted therein. As a result, in the conventional technology, the steel ball (B) 9
This solves the problem that there was a high chance of it falling off because it could be inserted from anywhere in the space B15b.

With the above configuration, the steel ball (
B) 9 is that the time of the free state caused by the repulsion of the hammer 3 is shortened, and there is only one passage through which the hammer cam can fly out from the end face 16, so the chance of it flying out is greatly reduced. I can do it.

As described above, according to the present invention, the 41-person groove is provided on the end face of the hammer cam so that the steel ball (B) can be installed only in one place, and the hammer retreat 1 tF is regulated by the spring seat instead of the cam end point. The structure and 1. Therefore, the chance of the steel ball (B) flying out can be minimized, and damage to parts such as the claw case and hammer can be prevented.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional side view of the impact re/te striking mechanism, Fig. 2 is a model diagram of the hammer at its maximum retraction, which is comparable to the conventional spindle cam and hammer cam, and Fig. 3 is the spindle cam and hammer cam of the present invention. Fig. 4 is a top view of the hammer according to the present invention, Fig. 5 is a sectional view taken along line C-C in Fig. 4, and Fig. 6 is a steel ball (B).
FIG. 7 is a model diagram showing an assembled state of the device, and a model diagram taken in the right angle direction of FIGS. In the figure, 1 is a spindle, 2 spindle cams,
3 is a hammer, 4 is a hammer cam, 5 is a steel hole (A
), 6u spring seat, 7 is the end surface of the spring seat, 8-inch hammer inner diameter stepped part, 9 is steel ball (B),
1O is a compression neck, 11 is an anobile, 12tj is a no-toe case, 13 is a no-ma clutch pawl, 14 is a groove for inserting a steel ball (B), 15a is a space As15b is a space B116 is an end face of a no-ma cam . Name of patent applicant Hitachi Koki Co., Ltd./Figure v-7
Figure 4 Figure 5 ・OlI2] Off leap

Claims (1)

[Claims] A cam is formed on each of the spindle and the hammer, which converts the rotary motion of the hammer into a backward motion in the axial direction via a steel ball, and when a certain delivery torque is reached, the hammer retreats, causing the anvil and hammer to move. In an impact wrench, the amount of retraction of the hammer is determined by the amount of retraction of the hammer in the spring. The structure is such that the steel ball interposed between the hammer cam and the spindle cam is not located at the end point of the mutual cam trajectory, and the hammer is forcibly retreated in the axial direction by a press or the like. A steel ball escape prevention mechanism in an impact wrench, characterized in that the steel ball escape prevention mechanism in an impact wrench is characterized in that the steel ball is structured so that a cutter provided at the end face of the hammer cam cannot be inserted when the steel ball is inserted between both cams.