EP1512494B1 - Screwdriver - Google Patents

Abstract

A screwdriver for screws with inner profile has a correspondingly shaped tip to locate into the profile. A spring grip is fitted to the tip to secure the tip into the recessed head of the screw. The spring grip can have various shapes and is either fitted to the tip or comprises an extension of the tip, to grip into the recessed head. A simple spring grip has a spiral shape while other variations include circular grips and sprung tags.

Description

The invention relates to a screwdriver according to the preamble of claim 1.

A screwdriver is any tool for screwing in and out of screws, d. H. both hand tools and screwdriver bits (bits) for power driven screwdrivers.

Furthermore, the invention relates to screwdriver whose output tip is formed with a profile, so that the output tip can axially engage in a corresponding inner profile of a screw to transmit the required torque from the output tip to the screw. The profile can be formed in any manner known per se, in particular as a cross-slot profile, polygonal profile, in particular hexagonal profile, Torx profile, etc.

To screw in particular screws in poorly accessible places and to be able to turn it, it is known to hold the screw by clamping on the output tip of the screwdriver.

In these known solutions (eg WO 03/006210 A ), the clamp engages the outer circumference of the output tip in the region of the profile. The elastic clamping is thus in the region of the profile surfaces, with which the torque is transmitted from the output tip to the screw. The clamping thus affects the effective for the torque transmission profile surface of the output tip.

The invention has for its object to form a screwdriver with a provided on the output tip clamp so that the clamping does not affect the torque transmission from the output tip to the screw.

This object is achieved by a screwdriver with the features of claim 1.

Advantageous embodiments of the invention are specified in the subclaims.

The essential idea of the invention is to arrange a resilient clamping element on the output tip. As a result, the clamping element does not take up any peripheral surface of the profile of the output tip, which is required for engagement in the internal profile in the screw and is effective for transmitting the torque from the output tip to the screw. The inner profile of the screw is formed in a blind hole of the screw, wherein the torque transmitting profile surfaces form the axis-parallel wall surfaces of this blind hole. The reason of the blind hole is due to the production more or less conical deepened. This fact makes use of the invention by the pressed in front of the end face of the profile clamping element is pressed into this bottom of the blind hole when the output tip is fully inserted into the inner profile. The profile surfaces of the output tip and the inner profile of the screw are thus completely available for torque transmission.

The clamping element is a spring element which is fastened to the end face of the output tip. This spring element projects beyond the outer contour of the profile of the output tip with a resilient part at least in a peripheral region. If the output tip is inserted into the inner profile of the screw, then this resilient part of the spring element is pressed into the outer contour of the profile of the output tip, whereby the spring element rests with its elastic restoring force on the inner wall of the screw. The spring element may consist of an elastic plastic or is preferably a metallic molded part.

The projecting over the outer contour of the profile of the output tip resilient part of the spring element is designed as a spring tongue. This is preferably arranged with a free end spirally on the handling of the spring element. E-benso the circumferentially extending spring tongue can be connected at both ends with the spring element. The spring tongue is pressed during insertion of the output tip in the inner profile of the screw substantially radially inward.

Fig. 1

in einer vergrößerten perspektivischen Darstellung die Abtriebspitze eines Schraubendrehers mit einem Klemmelement in einer ersten Ausführung,

Fig. 2

einen Axialschnitt der in eine Schraube eingesetzten Abtriebspitze gemäß Fig. 1,

Fig. 3

eine vergrößerte Detaildarstellung aus Fig. 2,

Fig. 4

eine Fig. 1 entsprechende Darstellung mit einer zweiten Ausführung des Klemmelements, und

Fig. 5

eine Fig. 1 entsprechende Darstellung mit einer dritten Ausführung des Klemmelements.

In the following the invention will be explained in more detail with reference to embodiments shown in the drawing. Show it

Fig. 1

in an enlarged perspective view of the output tip of a screwdriver with a clamping element in a first embodiment,

Fig. 2

an axial section of the driven tip used in a screw according to Fig. 1 .

Fig. 3

an enlarged detail Fig. 2 .

Fig. 4

a Fig. 1 corresponding representation with a second embodiment of the clamping element, and

Fig. 5

a Fig. 1 corresponding representation with a third embodiment of the clamping element.

In the Fig. 1-3 a first embodiment of the invention is shown. The output tip 10 of a screwdriver 12 is with a profile 14 is formed, which is a Torx profile in the illustrated embodiment. To turn a screw 16 off or in, the output tip 10 is inserted axially into an inner profile 18 of the screw 16. The inner profile 18 corresponds to the profile 14 of the output tip 10. In the illustrated embodiment, therefore, the inner profile 18 is also formed as a Torx profile.

At the axial end face 20 of the output tip 10, a clamping element is arranged in front of the profile 14. This clamping element is designed as a spring element 22. The spring element 22 is produced as a molded part, for example, as a stamped part from a spring-metal sheet, which, depending on the size of the output tip, has a sheet thickness of, for example, 0.1-0.5 mm. The spring element 22 has an approximately circular disk-shaped core 24, from which protrude spirally extending in the circumferential direction spring tongues 26. In the embodiment of Fig. 1 two spring tongues 26 are provided diametrically opposite each other. The spring tongues 26 are integrally connected at one end to the core 24, while the other end of the spring tongues 26 is free and thus can be deflected resiliently in the radial direction.

The spring element 22 is attached to the end face 20 of the output tip 10. For this purpose, the spring element 22, for example, with its core 24 placed on an axially central pin 28 of the output tip 10 and riveted by means of this pin 28 with the output tip 10. Alternatively, the spring element 22 could also be connected to the end face 20 by spot welding. The spring element 22 is dimensioned such that its core 24 lies completely concentrically within the outer contour of the profile 14. The spring tongues 26 extend from the core 24 spirally within the outer contour of the profile 14 and protrude only with their free ends on the outer contour of the profile 14 addition. For this purpose, the spring element 22 is mounted on the end face 20 so that the free ends of the spring tongues 26 lie in the region of the bottom of a profile groove of the profile 14, as in Fig. 1 you can see.

From the FIGS. 2 and 3 the effect is recognizable. If the output tip 10 is inserted with its profile 14 into the inner profile 18 of the screw 16, then the inner profile 18 presses the free ends of the spring tongues 26 inwards. The spring tongues 26 are thus under their elastic restoring force on the inner profile 18 and hold the screw 16 clamped on the output tip 10. The formed with the inner profile 18 blind hole of the screw 16 has a conical base 30, which is due to the production of the axial cylindrical section the inner profile 18 connects. If, for screwing in the screw 16, the output tip 10 is inserted into the blind hole of the screw 16, the profile 14 of the output tip 10 penetrates into the blind hole of the screw until the end face 20 of the output tip 10 reaches the inner end of the inner profile 18. The spring element 22 is then in the subsequent conical region of the bottom 30 of the blind hole, as shown in the enlarged view of Fig. 3 can be clearly seen. The outer profile surface of the profile 14 comes over the entire axial profile depth of the inner profile 18 with this for positive engagement, so that over the entire axial profile depth of the inner profile 18, the torque from the output tip 10 can be transferred to the screw 16.

In the embodiment of Fig. 1 The spring element 22 has two spiral spring tongues 26, the free ends of which protrude beyond their outer contours in diametral grooves of the profile 14. It is readily apparent that a different number of spring tongues 26 may be provided. Essential is only that the free ends of the spring tongues coincide with a groove of the profile 14.

In Fig. 4 Accordingly, a modified embodiment is shown, in which three each offset by 120 ° against each other spiral spring tongues 26 are provided.

Fig. 5 shows a further embodiment, in which the spring element consists of a radially elastically deformable tire 32 which is secured by means of spokes 34 to the seated on the pin 28 core 24. Die beiden Enden 32, 32 sind in der radial direction und der Tire 28 bzw. The free arc lengths of the tire 32 form spring tongues which engage over the outer contour of the profile 14 to the outside and can be pressed radially inward under elastic deformation when the output tip 10 is inserted into the screw 16.

As the above statements show, the clamping elements in all embodiments cause a non-positive frictional engagement between the output tip 10 and the screw 16. By this frictional engagement, the screw 16 is held on the output tip 10. By an axial force between the output tip 10 and the screw 16, the output tip 10 can be inserted against this friction force in the inner profile 18 or pulled out of this.

Although in the illustrated embodiments, the invention is illustrated with reference to a Torx profile, it is readily understood that the invention clamping can be used in other profiles.

In a polygonal profile, z. B. a hexagonal profile, the spring tongues 26, 32 project beyond the respective polygon sides of the polygonal profile. In a cross-slot profile, the spring tongues 26, 32 engage over the bottom of the groove formed between the legs of the cross-slot profile.

LIST OF REFERENCE NUMBERS

10

drive tip

12

screwdriver

14

profile

16

screw

18

internal profile

20

face

22

spring element

24

core

26

spring tongues

28

spigot

30

reason

32

tires

34

spoke

Claims (5)

1. A screwdriver having a drive tip (10) designed with a profile (14) for axial engagement in a corresponding internal profile (18) of a screw (16) and having a springy clamping element (22) provided to clamp against the drive tip (10), with which, during engagement, the drive tip (10) is resiliently applied against the wall of the inner profile (18), wherein the clamping element (22) is a spring element that is disposed in front of the end face (20) of the profile (14) and is attached to the end face (20) of the drive tip (10),
   characterised in that in at least one circumferential area of the profile (14) in front of its end face (20) the spring element (22) protrudes beyond the external contour of the profile (14) by at least one flexible tongue (26, 32) that extends in the circumferential direction and is radially inwardly pliable.
2. A screwdriver according to claim 1,
   characterised in that the at least one flexible tongue is connected by one end to the spring element (22), runs substantially in a spiral shape and by its free end projects over the external contour.
3. A screwdriver according to claim 1,
   characterised in that the at least one flexible tongue (32) runs in the circumferential direction, is connected by both ends to the spring element (22) and in its central area is radially inwardly bendable.
4. A screwdriver according to one of claims 1 to 3,
   characterised in that the spring element (22) is a shaped part made from a flexible metal sheet.
5. A screwdriver according to one of claims 1 to 3,
   characterised in that the spring element (22) is a plastic component.

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