EP1506843B1 - Clamping device for hexagonal bits - Google Patents

Description

The invention relates to a clamping device with a hexagonal socket for hex bits with the features according to the preamble of claim 1.

A variety of glands is carried out with mechanical or electromechanical aids, with mains or battery-operated drills, mechanical ratchets or the like. Be used. As a universally applicable tool so-called hexagon bits have found widespread use. These hex bits have a substantially hexagonal cross-section, which is held in corresponding hex shots, wherein the torque is transmitted from the hexagonal socket to the hexagon bit via surface pressure on the side surfaces of the hexagon bit. To adapt to different screwing an easy interchangeability of hex bits is desired. Corresponding connectors allow, as needed, the use of slotted or Kreuzschlitzbits, bits for receiving screw nuts or other adapted to the particular purpose hex bits. As an international standard, hex bits in the quarter-inch format have prevailed.

In operation, the determination of the bits in the axial direction has been found to be problematic. There are known hexagonal shots with an integrated magnet, wherein the magnet is intended to prevent unintentional falling out of an inserted bit. On the other hand, the bit should be magnetized to ensure adherence of the screws to the bit. The holding force of the magnet must not exceed a certain level, so that used hexagon bits can be replaced, for example, after exceeding a wear limit without tools by hand. In particular, after screwing under application of high torque, it may happen that a hexagon bit "stuck" on the screw head and slips when removing the screwdriver from the hexagonal socket. Longer bits or special bits have a higher dead weight, for which the magnetic holding force may be too low.

There are still clamping devices with a hexagonal socket known in which clamped hex bits are held by means of suitable locking elements in the axial direction of liquid form. For this purpose, the hexagon bits latch recesses, for example in the form of a circumferential annular groove, in which engages the locking element. To insert or remove appropriate bits a cumbersome unlocking is required.

From the US 2003/025281 A1 is a clamping device with a hexagon socket for hex bits known. Radially and axially deflectable locking elements in the form of balls are provided for engagement in a locking recess of the hexagon bit.

The spherical locking element protrudes in a rest position radially inwardly into the hexagonal socket. In this case, it is defined with respect to its radial position by a cylindrical retaining wall of a locking sleeve. When inserting the hexagon bits, it is displaced so far in the axial direction of insertion against the force of a rotating spring ring that it can be deflected radially and releases the hexagonal socket for complete insertion of the hexagon bit. The leadership and bias of the locking element by the circumferential spring ring is inaccurate and with respect to the effective direction is not precisely defined. The reliability of the locking of the hexagon bit can be improved.

The invention has for its object to provide a corresponding clamping device, are held reliably in the hex bits and easily replaceable.

The object is achieved by a clamping device with the features of claim 1.

For this purpose, a clamping device is proposed with a locking element, wherein the locking element is fixed in the rest position with respect to its radial position and is displaceable in the axial direction of insertion of the hexagon bits in a radial deflection releasing receiving position. In this case, the locking element is in the absence or inserted hexagon bit in its rest position. To insert the hexagonal bit is pushed in the axial direction of insertion in the hexagonal socket until it to the inwardly into the hexagonal socket protruding and locked in the rest position locking element strikes. As the bit is pressed further in, the locking element is displaced in the axial direction of insertion until it reaches a receiving position. There, the locking element is deflectable in the radial direction, as a result of which the hexagon bit can be pushed completely into its hexagonal socket. Upon insertion of the bit takes place in this way an automatic unlocking, wherein the locking element is then returned to its rest position and holds the hexagon bit form-fitting captive. The insertion of a bit is limited to the insertion process. A separate unlocking is not required.

The locking element is designed such that it is axially displaceable against the force of a compression spring, in particular enclosing the hexagonal receptacle. After deflection of the locking element in the release position this can then automatically return to the locked rest position. A manual locking is not required. A designated, the hexagonal socket enclosing helical compression spring requires only small volume.

Between the locking element and the compression spring an abutment plate is arranged. The contact plate has in the region of the locking element on an inwardly inclined slope. It is a precisely defined adhesion between compression spring and locking element achievable. The inwardly inclined slope results in a radially inwardly directed force component which assists in locking the locking element into the locking recess of the hex bit. In an advantageous embodiment the slope in Kalottenform results in a good leadership of trained as a ball locking element.

For easy removability of a clamped hexagon, the control sleeve is designed such that it is displaceable from its rest position in the direction of a free end of the hexagonal socket against the force of a compression spring. To remove a clamped and locked bits, the locking sleeve is only to pull in the same direction in which the bit is to be removed. When moving the locking sleeve, the locking element is released. The hexagon bit can be removed. The locking sleeve can be pulled with only two or three fingers of one hand and at the same time the released bit with the same fingers and in the same direction. The compression spring leads to an automatic return of the locking sleeve in its initial position, as a result, the locking element is locked in its rest position. Cumbersome separate locking or unlocking operations can be omitted.

The hexagonal seat advantageously has a slot within which the locking element is guided in the axial direction. It is given by simple means a longitudinally limited and immovably fixed in the circumferential direction guiding the locking element.

For a simple and reliable locking or release of the locking element in the radial direction, a locking sleeve is advantageously provided with a retaining wall, wherein the retaining wall holds the locking element in its rest position radially outwardly and thus locked. The resulting positive locking of the locking element leads to a great holding power. The clamped and locked hexagon bit can hardly be lost even under difficult conditions.

In an expedient development, a radially outwardly widening chamfer is provided in the axial direction on the side opposite the free end of the retaining wall. As well as the inwardly inclined slope of the contact plate, the bevel leads to a radially inwardly directed, acting on the locking element force component. The locking element is reliably pressed into the locking recess of the hexagon bit. In the axial direction is advantageous provided on the free end facing side of the retaining wall a radially inwardly extending stop. This results in a precise relative position of the locking sleeve to the locking element. The required during insertion of the bit for unlocking axial travel of the locking element and also the axial Entriegelungsweg the locking sleeve when removing the bits are precisely predetermined and adaptable to the needs of the user.

To reduce the production costs and to simplify the assembly, the locking sleeve is expediently designed as a substantially rotationally symmetrical rotary part. An easy unlockability for removing a clamped bits, the locking sleeve advantageously on the outside a surface structuring. The sleeve is easily operable even under dirty environmental conditions as well as with protective gloves.

The locking element is advantageously designed as a ball. The relative movements between the ball, hexagon bit, contact plate and locking sleeve can be performed essentially unrolling. There is only a slight wear.

When integrated into the tool shaft of a machine tool clamping device whose locking sleeve expediently has a smaller outer diameter than the outer diameter of a Bohrfutteraufnahme at the corresponding end face of the tool shaft. With a corresponding design of the drill chuck this can be pushed over the mounted clamping device and fixed to the Bohrfutteraufnahme become. A retooling example of a drill from screwing to drilling operation can be done without disassembly of the clamping device for hex bits. The clamping device is secured against loss.

Fig. 1

in einer Längsschnittdarstellung die Werkzeugwelle eines Bohrschraubers mit einer stirnseitig integrierten Spanneinrichtung und einem teilweise eingeschobenen Sechskantbit,

Fig. 2

die Anordnung nach Fig. 1 mit dem relativ dazu weiter eingeschobenen, das Riegelelement in eine Freigabeposition drückenden Sechskantbit,

Fig. 3

die Anordnung nach den Fig. 1 und 2 mit eingerastetem und verriegeltem Sechskantbit,

Fig. 4

die Anordnung nach den Fig. 1 bis 3 mit gezogener Riegelhülse und teilweise entnommenen Sechskantbit.

An embodiment of the invention is described below with reference to the drawing. Show it:

Fig. 1

in a longitudinal sectional view of the tool shaft of a drill with a frontally integrated clamping device and a partially inserted hexagon bit,

Fig. 2

the arrangement after Fig. 1 with the hexagon bit pushed further in relation to this, pushing the locking element into a release position,

Fig. 3

the arrangement after the Fig. 1 and 2 with latched and locked hexagon bit,

Fig. 4

the arrangement after the Fig. 1 to 3 with drawn locking sleeve and partially removed hexagon bit.

Fig. 1 shows in a longitudinal sectional view of the tool shaft 19 of a cordless drill in the region of its front end 20. It may also be provided a tool shaft 19 of a mains powered drill or other hand-held machine tool. In the front end 20 of the tool shaft 19, a clamping device 1 for a hexagon bit 3 is integrated. The clamping device 1 comprises a hexagonal socket 2, which is formed integrally with the tool shaft 19. In the exemplary embodiment shown, the hexagonal receptacle 2 has the cross section of a regular hexagon, wherein the hexagon bit 3, which has a hexagonal design in cross section, can be inserted with little play in the insertion direction indicated by the arrow 6. Instead of the hexagonal cross section of the hexagonal receptacle 2, a suitable triangular cross section or the like can also be provided. It may also be expedient to provide, instead of the integrated into the tool shaft 19 embodiment of the clamping device 1 designed as a separate component clamping device 1, for example, for fixing in a three-jaw chuck, in a ratchet or the like.

It is a locking element 4 is provided, which is formed in the illustrated embodiment as a ball 18. It may also be a latch-shaped locking element 4, a spring wire or the like. Be appropriate. The locking element 4 is held in a slot 11 of the hexagonal socket 2 and protrudes radially inwards into the hexagonal socket 2. The hexagonal receptacle 2 is enclosed on the outside in approximately its entire length by a locking sleeve 13. The locking sleeve 13 is formed as a rotationally symmetrical rotary part. On the inside, the locking sleeve 13 has a circumferential cylindrical retaining wall 12, which rests against the locking element 4 on the outside. In this case, the locking element 4 is shown lying in its rest position and thereby blocking or locking it radially outward by means of the retaining wall 12.

By means of a helical spring 8 formed as a compression spring 7 a bearing plate 9 is pressed axially against the locking element 4 in the direction of a free end 14 of the clamping device 1. In this case, the abutment plate 9 is located by means of a radially inwardly inclined bevel 10 on the locking element 4, whereby this is biased radially inwardly and axially in the direction of the free end 14. The slope 10 may be formed as a plane, a dome or the like. Due to the axial force component, the locking element 4 is located at a free end 14 facing the end of the elongated hole 11 and also on a stop 17 of the locking sleeve 13. The stop 17 extends radially inwardly on the free end 14 facing side of the retaining wall 12. In the in Fig. 1 shown rest position of the locking element 4, the hexagon bit 3 in the direction of the arrow 6 as far inserted until it abuts the inwardly projecting into the hexagonal receptacle 2 locking element 4.

The locking element 4 is axially displaceable within the elongated hole 11 against the biasing force of the compression spring 7 in the direction of the arrow 6.

In the region of its end face 20, the tool shaft 19 has a chuck receptacle 21 on which, for example, a three-jaw chuck can be fixed. The outer diameter D _{2 of} the Bohrfutteraufnahme 21 is greater than the outer diameter D _{1 of} the locking sleeve thirteenth

Fig. 2 shows the arrangement after Fig. 1 with a partially further inserted hexagon bit 3. The locking element 4 is together with the hexagon bit 3 axially in the direction of the arrow 6 relative to the in Fig. 1 moved rest position shown and has taken a recording position. In the receiving position shown, the locking element 4 is so axially displaced relative to the retaining wall 12, that the retaining wall 12 is no longer on the outside of the locking element 4. The locking element 4 is pushed in its receiving position shown so radially outward that it no longer protrudes into the hexagonal socket 2. From the in Fig. 2 As shown, the hexagon bit 3 can be fully inserted up to a stop 26, wherein the locking element 4 is pressed by the force of the compression spring 7 in the axial direction against the chamfer 16.

In the arrangement shown, only one locking element 4 is provided, as a result of which, in the case of the axial deflection shown, the contact plate 9 is inclined. The slope 10 of the bearing plate 9 is so far inwardly inclined that it exerts a radially inwardly acting force component on the locking element 4 even with inclined contact plate 9 and prevents complete emigration of the locking element 4 to the outside. It is also possible to provide two or more locking elements 4.

Fig. 3 shows the arrangement according to the Fig. 1 and 2 , in which the hexagon bit 3 is inserted to the stop 26. The hexagon bit 3 has a locking recess 5, which is formed in the embodiment shown as a circumferential groove. Other suitable recesses, such as blind holes or the like, may be useful. The slope 10 of the investment plate 9 and the chamfer 16 within the locking sleeve 13 (FIG. Fig. 2 ) cause via the pressure force of the coil spring 8, a radially inwardly directed force component, as a result, the locking element 4 is pressed into the locking recess 5. With the locking element 4 from the in Fig.2 shown position slides along the outer contour of the hexagonal bite 3 in the locking recess or rolls, it is by means of the bearing plate 9 initially radially inwardly into the locking recess 5 and then in the axial direction, in the Fig. 3 moved rest position shown. The retaining wall 12 of the locking sleeve 13 encloses the locking element 4 on the outside form fit. In the Fig. 3 shown rest position of the locking element 4 corresponds to the rest position after Fig. 1 , The radially outwardly fixed locking elements 4 causes after Fig. 3 by its engagement in the locking recess 5 a form-fitting in the axial direction, captive determination of the hexagon. 3

The locking sleeve 3 is slidably guided in the axial direction on the outside of the hexagonal socket 2. In the region of the free end 14, the inner side of the locking sleeve 13, a compression spring 15 is arranged, which is supported in one direction against a flange 27 of the locking sleeve 13 and in the opposite direction against a stop ring 23. The stop ring 23 is supported in the axial direction by means of a spring ring 24 held in a circumferential groove 25. The locking sleeve 13 is slidable against the force of the compression spring 15 in the direction of the free end 14 or against the direction indicated by the arrow 6 inserting direction 6.

To remove the hexagon bit 3 from the clamping device 1, the locking sleeve 13 accordingly Fig. 4 be moved against the force of the compression spring 15 and counter to the direction of insertion 6. The locking element 4 remains under the action of the compressive force of the coil spring 8 in abutment with the located on the side of the free end 14 end of the slot 11. The locking sleeve 13 is so far against the insertion direction 6 shifted that the retaining wall 12, the locking element on the outside not more encloses. The locking element 4 is released radially outward and thereby displaced so far outward that it no longer protrudes into the hexagonal receptacle 2 and the locking recess 5. The hexagon bit 3 can be removed against the insertion direction 6. The removal direction and the necessary to release the pulling direction of the locking sleeve 13 match. The pulling of the locking sleeve 13 of the in Fig. 3 shown position in the position Fig. 4 and taking place in the same direction removal of the hexagon bit 3 can be done simultaneously and with one hand. For better grip of the locking sleeve 13, this has on the outside a surface structuring, which is formed by two circumferential grooves 22 in the illustrated embodiment.

After releasing the locking sleeve 13, this is under the action of the compression spring 15 automatically in the in Fig. 1 moved position shown, wherein by means of the chamfer 16 and the slope 10 of the contact plate 9, the locking element 4 radially inwardly into the hexagonal socket 2 protruding and thus in the rest position Fig. 1 is pressed.

Claims (9)

1. Clamping device (1) with a hexagon socket (2) having a free end (14) for hexagon bits (3), comprising a radially displaceable locking element (4) for engagement with a locking recess (5) of the hexagon bit (3), wherein the locking element (4) radially projects inwards into the hexagon socket (2) in a neutral position, wherein the locking element (4), which is in particular designed as a ball (18), is in the neutral position fixed by a cylindrical retaining wall (12) of a locking sleeve (13) in terms of its radial position and displaceable in the axial direction of use (6) of the hexagon bit (2) against the force of a compression spring (7) into a locating position allowing its radial displacement,
   characterised in that, between the locking element (4) and the compression spring (7), a locating plate (9) is provided which, in the region of the locking element (4), has a radially inward-oriented bevel (10), whereby the locking element (4) is preloaded radially inwards and axially in the direction of the free end (14), and in that the locking sleeve (13) is displaceable against the force of a compression spring (15) from its neutral position towards the free end (14) of the hexagon socket (2).
2. Clamping device according to claim 1,
   characterised in that the locking element (4) is axially displaceable against the force of a compression spring (7) encircling the hexagon socket (2).
3. Clamping device according to claim 2,
   characterised in that, between the locking element (4) and the compression spring (7) designed as a coil spring (8), a locating plate (9) is provided which, in the region of the locking element (4), advantageously has a radially inward-oriented bevel (10).
4. Clamping element according to any of claims 1 to 3,
   characterised in that the locking element (4) is guided in a slot (11) in the axial direction.
5. Clamping device according to any of claims 1 to 4,
   characterised in that a bevel (16) widening radially outwards is provided on the side of the retaining wall (12) which is opposite the free end (14) in the axial direction.
6. Clamping device according to claim 5,
   characterised in that a stop (17) extending radially inwards is provided on the side of the retaining wall (12) which is adjacent to the free end (14) in the axial direction.
7. Clamping device according to claim 5 or 6,
   characterised in that the locking sleeve (13) is designed as a rotary part which is substantially rotationally symmetrical and is in particular provided with a surface structuring on the outside.
8. Clamping device according to any of claims 1 to 7,
   characterised in that it is mounted on a tool shaft (19) of a hand-guided power tool, in particular of a cordless drill or the like, and in that it is integrated into the end of the tool shaft (19).
9. Clamping device according to claim 8,
   characterised in that a drill chuck location (21) is provided in the region of its front end (20), the outer diameter (D₁) of the locking sleeve (13) being smaller than the outer diameter (D₂) of the drill chuck location (21).

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