DE9208014U1 - Screw-in tool - Google Patents

Description

IRON FEEDER SPEISER&P/VPTNER

Bremer. ■ Municien

Patent attorneys

European Patent Attorneys

Dlpl.-Ing. Günther Eisenführ Dipl.-Ing. Dieter K. Speiser Dr.-Ing. Werner W. Rabus Dlpl.-Ing. Jürgen Brügge* Dlpl.-lng. Jürgen Kllnghardi

European Patent Attorney Dipl.-Phys. R. Michael Janolle

Patent Attorney

DIpI.-Ing. Thomas Heun

Lawyer
Ulrich H. Sander

•Munich

Your sign Our sign Bremen

Wagschal W 735 15 June 1992

New registration

Gebr. Wagschal GmbH & Co. KG
Gutenbergstrasse 3/4, 2804 Lilienthal

Screw-in tool

Description

The invention relates to a screwing tool with a handle part, in one end of which a receiving part for tool attachments is rotatably mounted, as well as a force transmission element acting between the two parts, through which a torque is exerted on the receiving part when the handle part is rotated in one direction and when rotated in the opposite direction the receiving part essentially runs freely.

These tools are generally referred to as ratchets. They can be used with various attachments.

TH/cm

Martinisirasse 24 · D-28OO Bremen I · Telephone O42 1-333&Xgr;-&Ogr; · Ff.x 0421-363335 Telex 244O2O fepatd ■ Datex-P45421 O432I

and are used to tighten nuts, screws or similar.

These tools are also used in dental technology, where they are used in a smaller version to screw in dental implants. However, the force transmission elements between the handle and the receiving part, which lock in one direction of rotation, are particularly unsuitable for these applications, as they produce cracking noises and corresponding shocks during freewheeling (reverse rotation). Since such shocks are transferred directly to the jawbone and spread there, they can be extremely unpleasant for a patient.

The invention is therefore based on the object of creating a screwing tool of the type mentioned at the beginning, in which the reverse rotation is noise- and vibration-free.

This task is solved in the case of the rotary tool mentioned at the beginning in that the force transmission element is a helical spring, one end of which is attached to the receiving part or the handle part and the windings of which run freely in a narrow annular gap provided between the receiving part and the handle part and at least partially rest against the handle part and/or the receiving part, so that when the handle part is rotated in one direction, the helical spring rests against the handle or receiving part opposite the attachment point in a locking manner and thereby causes a rotationally fixed coupling between the two parts.

An advantage of this solution is that the screwing tool according to the invention can be manufactured relatively inexpensively, since no particularly tight tolerances have to be maintained. Furthermore, the screwing tool can also be produced in very small versions.

In a preferred embodiment, the helical spring can be formed by only one winding, which, depending on the torque to be applied and the material used, can also cover an angular range of less than 360°.

Further details, features and advantages of the invention emerge from the following description of embodiments based on the drawings:

Show it:

Figure 1 shows the overall view of a screwing tool,

Figure 2 is a partially sectioned view of the screwing tool,

Figure 3 is a view of the screwing tool according to arrow A in Figure 2 and

Figure 4 shows another embodiment of the force transmission element according to the invention.

Figure 1 shows the overall view of a screwing tool, generally referred to as a ratchet. This tool has a handle part 1, in one end of which a receiving part 2 for various tool attachments is rotatably mounted. For this purpose, the receiving part is equipped with a corresponding attachment 3.

■- 4 -

to which the tool attachments are attached. A force transmission element is provided between the handle part 1 and the receiving part 2, through which the receiving part can freely rotate in one direction relative to the handle part, while a torque for tightening dental implants or the like can be transmitted in the other direction.

Figure 2 shows a side view and a partially sectioned representation of the receiving part 2 and the force transmission element, which is in the form of a helical spring 4 with several windings. This helical spring 4 is located in an annular gap 5 between the handle part 1 and the receiving part 2. Furthermore, it is particularly clear from this representation that the annular gap is "narrow ^{" 11} in the sense that the windings of the helical spring 4 fill it almost completely. The annular gap is therefore only slightly wider than the diameter of the wire material used for the helical spring.

Figure 3 shows a schematic top view according to arrow A in Figure 2. In this embodiment, one end of the coil spring 4 is attached to the receiving part 2. The coil spring is formed by only one winding, which, starting from the fastening point 6, encloses the receiving part 2 in an anti-clockwise direction and covers an area of slightly less than 3 60°. The coil spring 4 rests at least partially on both the handle part 1 and the receiving part 2. If the handle part is turned anti-clockwise, i.e. in the winding direction starting from the fastening point, the spring is slightly contracted in the winding direction due to the friction with the handle part, reducing

This reduces its circumference and presses against the receiving part, so that friction is reduced and the receiving part 2 runs freely relative to the handle part 1.

If you turn the handle part 1 clockwise, the opposite effect occurs. Since the coil spring rests at least partially against the handle part in the resting position, it is slightly moved along due to friction when the handle part is turned clockwise, which increases the circumference of the spring, the contact area with the handle increases and thus also increases the friction. This effect leads to a rotationally fixed coupling between the handle part and the receiving part after a relatively small angle of rotation, so that a torque can be transmitted from the handle part to the receiving part. This direction of rotation therefore inserts a dental implant, while the tool runs freely in the opposite direction.

If the coil spring is wound clockwise around the receiving part starting from its attachment point, the locking or free-running direction of rotation is reversed.

Figure 4 shows an alternative embodiment of the invention, in which the helical spring is attached to the handle part at one end and rotates anti-clockwise around the receiving part. The helical spring is again formed by only one winding. If the handle part is turned anti-clockwise in the illustration shown in Figure 4, i.e. starting from the attachment point of the helical spring in the winding direction, the receiving part runs freely, while in the opposite direction a lock and thus a torque

Transmission is achieved. By turning the handle part anticlockwise, the attachment point also rotates. Due to the at least partial contact of the coil springs with the receiving part and the friction caused by this, the circumference of the coil spring increases, so that the friction with the receiving part is reduced and this thus runs freely, while in the opposite direction of rotation the circumference of the spring is reduced. This causes the spring to contact the receiving part to a greater extent and in turn increases the friction with it, so that a rotationally fixed coupling and a corresponding torque transmission is achieved.

If the coil spring is wound clockwise starting from its attachment point on the handle part 1, the directions of rotation in which the receiving part runs freely or is coupled in a rotationally fixed manner are reversed.

By selecting the right material for the coil spring and by dimensioning the annular gap thickness accordingly, the principle according to the invention can be applied to both very large and very small screwing tools. For the transmission of particularly high torques, it is advantageous to increase the friction between the coil spring and the annular gap walls by roughening the surface.

Claims (4)

PROTECTION CLAIMS 1. Screw-in tool with a handle part, in one end of which a receiving part for tool attachments is rotatably mounted, and a force transmission element acting between the two parts, by means of which a torque is exerted on the receiving part when the handle part is rotated in one direction and the receiving part essentially runs freely when rotated in the opposite direction, characterized in that the force transmission element is a helical spring (4), one end of which is attached to the receiving part (2) or the handle part (1) and the windings of which run freely in a narrow annular gap (5) provided between the receiving part and the handle part and at least partially rest against the handle part and/or the receiving part, so that when the handle part is rotated in one direction, the helical spring (4) rests against the handle or receiving part opposite the attachment point in a locking manner and thereby causes a rotationally fixed coupling between the two parts. 2. Screwing tool according to claim 1, characterized in that the helical spring (4) is formed by a winding. 3. Screwing tool according to claim 2, characterized in that the winding exceeds an angular range of less than 360°. 4. Screwing tool according to at least one of claims 1 to 3, characterized in that the surface of the winding and/or the inner surfaces of the groove gap (5) are roughened.