JPH0546825Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] This invention is used to tighten screws such as hexagon socket set screws and hexagon socket bolts used in the assembly of electronic devices, their parts, and other objects. The present invention relates to a screwdriver that is used by being connected and supported by a driving means such as a stepping motor.

[Conventional technology]

This type of screwdriver, which has been well known in the past, is as shown in FIGS. 8 and 9.

In this conventional screwdriver, a shaft 105 is loosely fitted into an outer cylinder 101 having a motor shaft connecting part 102 at one end 103, and one end of the shaft inside the outer cylinder 101 is housed within the outer cylinder one end 103. It is always pressed by the spring 107, and the shaft 1
The other end of the shaft 105 is equipped with a screwdriver rod 106 that protrudes outside the outer cylinder, and the shaft 105 has a pin 108 that protrudes from the circumferential side. It was fitted.

According to this screwdriver, the motor shaft connecting portion 102 of the outer cylinder is connected to the shaft of the motor 111 via a suitable torque limiter 112. The motor 111 is supported by a movable base 113 that is driven reciprocally in the outer cylinder axis direction X by a drive means (not shown). Further, the outer cylinder 101 is supported by a holder 117 on a movable table 113 so as to be rotatable but relatively immovable in the X direction. A screw 115 partially screwed into the article 114 is a screwdriver rod 1.
06, the movable base 113 is advanced toward the screw 115, and the rod 106 engages with the screw hole 115' of the screw 115. At this time, the spring 107 is slightly compressed, and its restoring force keeps the rod 106 engaged with the screw hole.

When the motor 111 is operated in this way, the outer cylinder 1
01 is turned, one side edge 110 of the window 109 of the outer cylinder hits the pin 108, the shaft 105 and therefore the rod 106 are turned, and the screw 115 is inserted into the article 114.
It is tightened by turning.

As the screw 115 advances into the article 114, the shaft 105 and rod 106 are urged by the spring 107 to follow the screw.

[The problem that the idea attempts to solve]

However, if the screw 115 is small (for example, an M2 or M3 screw), the corner 106' of the rod 106 will bite into the side wall of the screw hole 115' as shown in FIG.
Even if you try to move the 06 backwards, there are many cases where you can't do it.

In such a case, it may come out if the rod 106 is rotated slightly in the opposite direction and then retreated, but if the reverse rotation is too much, the screw must be turned back in the direction of loosening the screw. Furthermore, when the screw 115 is held in place by a large force due to reverse rotation torque, it may become stuck in the opposite direction and cannot be removed.

In this way, insert the screwdriver rod 1 into the screw hole 115'.
If you try to forcefully remove the rod when the rod is stuck and cannot be removed, there will be problems such as damage to the screwdriver and various parts of the device including the screwdriver, or damage to the article.

To avoid such inconvenience, if you try to remove the rod 106 from the screw 115 manually,
This is very labor intensive and even in this case the item may be damaged. Furthermore, even if the screwdriver rod 106 is successfully removed, the article 11
4 production lines had to be stopped, resulting in significant damage.

Therefore, when a screwdriver rod gets stuck in a screw hole, the present invention allows the screwdriver to be manually removed without damaging the screwdriver or the parts of the device that includes it, and without damaging the article to which the screw is to be attached. To provide a screwdriver that can be easily and quickly removed without twisting.

[Means to solve the problem]

In accordance with the above object, the present invention provides: an outer cylinder having a driving means connection part; a shaft loosely fitted in the outer cylinder and having a screwdriver rod; a push spring means at one end of the outer cylinder, which is attached to the other end of the outer cylinder and allows the shaft to be removed against the push spring means within a range limited by the spring extension limiting means provided at the other end; a return spring for pushing back into the cylinder; and a pin protruding from the side surface of the shaft and loosely fitted into a pin loose fit window provided on the peripheral side wall of the outer cylinder; The present invention provides a screwdriver characterized in that the edge on the other end side of the cylinder extends obliquely with respect to the circumferential direction of the outer cylinder.

[Effect]

In the screwdriver of the present invention, the driving means connecting portion of the outer cylinder is connected to the motor shaft.

In the initial state before screw tightening, the return spring extends to the position limited by the spring extension limiting means.
The shaft is placed in the initial retracted position by the return spring against the push spring means.

When an article with a partially screwed screw is placed in front of the screwdriver rod, the screwdriver with its motor is advanced toward the article and the screwdriver rod engages the hole of the screw. In this state, the shaft is pushed in relative to the outer cylinder and further retreats, taking a position where the return spring does not act. The shaft is therefore pushed by the push spring means and the rod is kept engaged with the threaded hole.

When the motor is operated in this manner and the outer cylinder is rotated in the screw tightening direction, one side edge of the pin loose fitting window contacts the pin on the shaft, causing the shaft to rotate. Accordingly, the screwdriver rod also rotates and the screw is tightened into the article.

When the screw tightening is completed, the motor is operated in reverse to rotate the outer cylinder slightly in the opposite direction, and the pin is placed in a position corresponding to the diagonally extending edge of the pin loose-fitting window on the other end of the outer cylinder. is forced to retreat.

When the rod is not biting into the screw hole,
The rod will be removed from the screw as it is, and the shaft and rod will take their initial positions relative to the outer cylinder.

When the rod is biting into the screw hole, only the outer cylinder moves backward while the rod and shaft remain stationary, and the shaft relatively moves in the direction of coming out of the outer cylinder while resisting the return spring. Further, as the outer cylinder retreats, the pin approaches the oblique edge of the pin loose fit window and comes into contact with it, and rotates slightly along the oblique edge in the opposite direction to the screw tightening direction. The shaft and rod also rotate in the opposite direction, and as a result, the end of the rod is released from the screw hole, and at that moment the shaft and rod are pushed back to their initial positions by the restoring force of the return spring.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

The screwdriver according to the embodiment shown in FIGS. 1 to 4 is a screwdriver for right-handed screws, and includes a shaft 2 that is loosely fitted into an outer cylinder 1. The outer cylinder 1 is closed at one end 11, and a motor connection part 13 is provided on the closed wall. The connecting portion 13 is connected to the shaft of a stepping motor 111 via a torque limiter 112. In addition,
The motor is supported on a movable base 113, and the movable base is supported on a base 116 so as to be able to reciprocate in the central axis direction X of the outer cylinder 1. The movable table is configured to be driven back and forth by a driving means such as an air cylinder (not shown). Further, a part of the outer cylinder 1 is supported by a holder 118 on a movable table 113 so as to be rotatable but relatively immovable in the X direction.

A shaft 2 is inserted into the outer cylinder 1 so as to be able to reciprocate in the X direction. A cap 121 is screwed into the other end 12 of the outer cylinder 1. The shaft 2 passes through the cap. A hexagonal screwdriver rod 10 is provided on a portion of the shaft 2 that protrudes from the outer cylinder.

A compression coil spring 3 as a pushing spring means is loaded in one end of the outer cylinder 1, and constantly pushes the one end 21 of the shaft 2 toward the other end 12 of the outer cylinder (outward of the outer cylinder).

Further, a return spring (compression coil spring in this example) 4 is loaded into the other end portion 12 of the outer cylinder in a state where it is fitted into the shaft 2 .

The return spring 4 is a spring stronger than the spring 3, and is connected to the shaft stepped portion 23 via a flat ring 7 slidably fitted to the other end (small diameter portion) 22 of the shaft 2.
, and pushes the shaft toward the one end 11 of the outer cylinder against the force of the spring 3.

The extension of the return spring 4 is limited by a spring extension limiting means 70.

The restricting means 70 consists of the ring 7 and a step 71 provided on the inner periphery of the outer cylinder, and when the return spring 4 extends a predetermined length, the ring 7 moves to the outer cylinder step 71.
, so that the spring 4 cannot be extended any further.

Incidentally, when the spring 4 is in sufficient contact with the shaft stepped portion 23 and the outer cylinder stepped portion 71 without the interposition of the ring 7, the ring is not necessarily necessary.

A pair of pins 8 are provided protruding from the circumferential side of the shaft inside the outer cylinder 1 so as to extend in opposite directions in the radial direction.

Each pin 8 is loosely fitted into a correspondingly provided pin loosely fitting window 9 in the peripheral side wall of the outer cylinder.

Both side edges 91 and 92 of each window 9 extend in the X direction, and an edge 93 on the other end 12 side of the outer cylinder extends obliquely to the circumferential direction of the outer cylinder.

In the initial state of the screwdriver as shown in FIG. placed in position. The spring 3 brings the shaft step 23 into contact with the ring 7.

In front of the screwdriver rod 10, a screw 115 such as a set screw with a hexagonal socket or a bolt with a hexagonal socket is inserted into an article 114.
When the screwdriver rod 10 is delivered partially screwed into the screw 115, the screwdriver together with the motor 111 is advanced toward the screw 115, and as shown in FIG. is engaged with. In this state, the shaft 2 is pushed back relative to the outer cylinder 1 and takes a position where the return spring 4 does not act. Therefore, the shaft 2 is pushed only by the spring 3, and the rod 10 is kept engaged with the screw hole.

Thus, when the motor 111 is operated and the outer cylinder 1 is rotated in the screw tightening direction (clockwise rotation) under a predetermined torque by the torque limiter 112, each pin loose fitting window 9 is rotated.
One side edge 91 of the shaft contacts the pin 8 on the shaft, causing the shaft 2 to rotate clockwise. Accordingly, the screwdriver rod 106 is also rotated clockwise, and the screw 115 is tightened onto the article 114.

When the screw tightening is completed, the motor is operated in reverse and the outer cylinder 1 is slightly rotated counterclockwise, and the pin 8 is placed at a position P corresponding to the diagonal edge 93 of the pin loose fitting window 9 (see FIG. 6). In this state, the entire vehicle is forced to retreat.

If the rod 10 is not biting into the screw hole, the rod will just come off the screw and the shaft 2 will be removed.
And the rod 10 assumes its initial position with respect to the outer cylinder 1.

When the rod 10 is biting into the screw hole 115', as shown in FIG. 5, only the outer cylinder 1 retreats while the rod 10 and shaft 2 remain stationary.
The shaft 2 relatively moves in the direction of coming out of the outer cylinder 1 while resisting the return spring 4. Further, as the outer cylinder 1 retreats, the pin 8 relatively approaches and abuts the diagonal edge 93 of the pin loose fitting window, as shown by arrow A in FIG. 6, and slides against the diagonal edge. At the same time, the shaft 2 and the rod 10 are rotated slightly in the counterclockwise rotation direction B, whereby the shaft 2 and the rod 10 are also rotated in the counterclockwise rotation direction, and as a result, the end of the rod is released from the threaded hole 115'.
At that moment, the shaft and rod are pushed back to their initial positions by the restoring force of the return spring 4.

Note that the present invention is not limited to the above-mentioned embodiments, and can be implemented in various other ways.

In the embodiment described above, the spring 3 in the one end 11 of the outer cylinder directly pushes the shaft 2, but as shown in FIG. One end of the shaft that contacts the bearing may be formed into a hemispherical surface 211 or a conical surface with a large apex angle. Also, the return spring 4
In the above embodiment, the ring 7 contacts the ring 7, but the ring may be replaced with a pivot ball bearing 6 and the shaft step portion may be formed into a conical surface 23', as shown in FIG. 7, for example. Bearings 5 and 6 contribute to the centering of shaft 2 and rod 10 in the initial state of the screwdriver. Further, the bearing 5 allows the shaft 2 to slightly axially run out in alignment with the screw 115 when there is a slight misalignment of the central axes between the screw 115, the shaft 2, and the rod 10. In this case, a sufficient gap is provided between the shaft 2 and the inner surface of the outer cylinder 1 to allow for the shaft runout. In addition, in order to tolerate the shaft runout, the bearing 6
It is desirable to leave a small gap (for example, 0.1 mm) between the ball 61 and the shaft small diameter portion 22.

Although it is convenient to provide a plurality of pins 8 at equal intervals around the shaft in terms of balance of rotational force, a plurality of pins 8 are not necessarily required. Furthermore,
One of the two pin loose fitting windows 9 has a diagonal edge 93
For example, it may be a simple rectangular window. In short, it is preferable that the edge of at least one window on the other end side of the outer cylinder is formed obliquely as described above.

Further, instead of the spring 3, an air spring may be used. In this case, for example, an O-ring may be fitted to the shaft 2 so that it can slide freely on the inner circumferential wall of the outer cylinder, and a suitable hole may be provided in the outer cylinder wall to supply compressed air from the outside to one end of the outer cylinder. .

[Effect of idea]

According to the present invention, when a screwdriver rod bites into a screw hole, the bite can be removed manually without damaging the screwdriver or any part of the device including the screwdriver, or without damaging the article to which the screw is to be attached. To provide a screwdriver that can be easily and quickly removed without twisting.

[Brief explanation of the drawing]

Figures 1 to 6 show an embodiment of the present invention. Figure 1 is a sectional view of the initial state before screw tightening work, Figure 2 is a plan view of the same, and Figure 3 is a screwdriver rod. Fig. 4 is a cross-sectional view of the state in which the screw is engaged with the screw hole, Fig. 4 is a plan view of the state in which the screw has started to be turned from the state shown in Fig. 3, and Fig. 5 is a plan view of the state in which the screwdriver rod is stuck in the screw hole and the outer cylinder is removed. 6 is an explanatory diagram of the relationship between the pin and the pin loose fitting window in the state shown in FIG. 5, FIG. 7 is a sectional view of another embodiment, and FIG. 8 and FIG. FIG. 9 is a sectional view and a plan view of a conventional example, and FIG. 10 is an explanatory diagram of a state in which a screwdriver rod is biting into a screw hole. DESCRIPTION OF SYMBOLS 1... Outer cylinder, 11... One end of the outer cylinder, 12... Other end of the outer cylinder, 13... Driving means connection part, 2... Shaft, 21... One end of the shaft, 22... Other end of the shaft , 23...Shaft stepped portion, 3...Press spring, 4...Return spring, 5, 6...Pivot ball bearing, 7...Ring, 70...Spring extension limiting means,
71...Inner step of outer cylinder, 8...Pin, 9...Pin loose fitting window, 91, 92...Both edges of window 9, 93...Diagonal edge of window 9, 10...Screwdriver rod.

Claims (1)

[Claims for Utility Model Registration] An outer cylinder having a driving means connection part, a shaft loosely fitted in the outer cylinder and having a screwdriver rod, the shaft for applying a pressing force outward of the outer cylinder to the shaft. a pushing spring means at one end of the outer cylinder, which is attached to the other end of the outer cylinder, and pushes the shaft into the outer cylinder against the pushing spring means within a range limited by the spring extension limiting means provided at the other end; a return spring for pushing the shaft back toward the outer cylinder, and a pin protruding from a side surface of the shaft and loosely fitted into a pin loose fitting window provided on the peripheral side wall of the outer cylinder, A screwdriver characterized in that the edge on the end side extends obliquely with respect to the circumferential direction of the outer cylinder.