Drill chuck for manual devices

Drill chuck for hand tools.

- Borrspindel för handanordningar.

The present invention relates to a drill chuck for hand tools, such as impact drills, hammer drills and the like, for receiving tools with at least two clamping jaws radially displaceably mounted on the chuck, adjustable with a conically sleeve rotatably and axially displaceably connected to the chuck and to the respective shank diameter of the plug end of the tool to be received via the insertion sleeve in threaded engagement with the seat member, the tool-side end region of the insertion sleeve having a tapered toothing to engage a receiving ring key in the receiving opening in the tapered sleeve.

In particular, drill chucks with radially adjustable clamping jaws are known in the field of impact drills. These clamping jaws are arranged radially, usually by means of a rotatable conical sleeve, and can thus receive tool diameters with different diameters, mainly cylindrical. Because the tools are tightened to such drill chucks exclusively by force, these drill chucks are not suitable for hammer drills with substantially high loads. While in impact drills, only a kind of vibrational movement is transmitted to the tool, in hammer drills or chisels, the movement of the hammer is transmitted to the insert end of the tool. For this reason, hammers and chisels have gained ground with chucks that allow the tools to be securely attached. In such seats, the radially adjustable feed members act together with the abutment surfaces of the tool insertion head. The power of such devices can only be fully utilized when the tools are attached to the chuck with limited clearance. Therefore, the seats are subjected to a relatively difficult task, which has hitherto been solved in that the tools have a unit insertion head for guiding inside the seat and, in addition, radially adjustable output means for axially and radially retaining the respective abutment surfaces of the tools. This resulted in very uneconomical sizing for the tools, as it was necessary to arrange insert heads that were either too large for small tools or too small for large diameter tools.

In order to avoid the above-mentioned drawbacks, it is an object of the present invention to provide a drill chuck which can formally fasten tools with different inserts and is thus suitable for hammer drills and can also be used in impact drills for force-tightening tools.

This is achieved according to the invention by providing an axially displaceable locking sleeve for non-rotatably connecting the insert sleeve to the conical sleeve, the insert sleeve at the second end position of the locking sleeve being non-rotatably connected to the conical sleeve and the locking sleeve at the second end position rotatable relative to the conical sleeve.

In order to set the drill chuck according to the invention, the conical sleeve and the setting sleeve must be released from the lock so that they can be rotated relative to each other. This is done by axially moving the locking sleeve. The desired diameter is then set with critical clearances and a critical prestress is provided. By pushing the locking sleeve back, the taper sleeve and the setting sleeve are reconnected so that the set diameter, clearance and preload of the drill chuck are maintained.

For setting the conical sleeve and preventing detachment during operation, it is expedient for the locking sleeve to be lockable in its end positions. The locking sleeve can be locked, for example, by a ring spring, a ball retainer or the like.

Relatively high torque is required for strong tool tightening. To accomplish this, it is common to provide a tapered sleeve or set sleeve with tapered teeth for engaging a ring gear wrench. However, this bevel gear is prone to soiling. In order to protect the tooth from contamination and also to keep the risk of damage low, it is advantageous that the taper tooth in the insert sleeve and the receiving opening in the taper sleeve can be covered by a locking sleeve in a position connecting the insert sleeve to the taper sleeve. Thanks to the axial displacement of the locking sleeve, both the setting sleeve and the toothing made on it become visible. After setting the drill chuck, the teeth are covered again by moving the locking sleeve back.

As such, the locking sleeve can be mounted on a setting sleeve or a conical sleeve. However, for practical reasons, it is expedient for the locking sleeve to be mounted non-rotatably and axially displaceably on the conical sleeve. In continuous use of the device, the clamping jaws and thus also the conical sleeve connected to them become relatively hot due to the impact energy transferred to the plug head. This is embarrassing when inserting a drill chuck. The locking sleeve surrounding the conical sleeve now substantially lowers the temperature of the outer, controllable part. This is especially true when the locking sleeve is made of a material with poor thermal conductivity, such as plastic.

To connect the locking sleeve to the setting sleeve, a simple groove / cam connection is sufficient. However, with a small number of grooves, the fine positionability of the drill chuck is limited. For an optimal fit of the drill chuck to the respective diameter of the plug head, it is therefore advantageous for the locking sleeve to have a toothing which can be connected to the corresponding counter-toothing in the setting sleeve. Although forehead toothing is also possible per se, the toothing is preferably formed as a longitudinal toothing.

Since the locking sleeve itself has only a securing function, the forces and moments acting on it are relatively small. For the compact construction of the drill chuck, it is therefore expedient for the toothing in the locking sleeve and the counter-toothing in the setting sleeve to be formed as sharp teeth. Sharp teeth have the advantage, in addition to simple manufacturing, that they allow a very fine-pitched adjustment of the drill chuck.

The invention will be explained in more detail below with reference to an exemplary drawing in which:

Figure 1 shows a drill chuck according to the invention in the locked state and

Figure 2 shows the drill chuck of Figure 1 in the unlocked state.

The drill chuck shown in Figures 1 and 2 has a sleeve-like chuck body, indicated in its entirety by reference numeral 1, with a stepped axial bore 1a. The rear, motor-side region of the axial bore 1a of the seat body I is provided with, for example, an internal thread Ib and a mandrel 2 threaded into this internal thread Ib.

5. A pin 6 is axially displaceably mounted inside the spindle 2. A conical sleeve, indicated by reference numeral 7, is mounted on the seat piece 1 in a non-rotatable but axially displaceable manner. A set sleeve, indicated by reference numeral 8, is connected in its entirety with the conical sleeve 7 in a rotatable but axially non-displaceable manner. The setting sleeve 8 is provided with a thread 8a which is connected to the outer thread Id of the seat piece 1. The setting sleeve 8 and the conical sleeve 7 connected thereto can thus be set axially by rotating the setting sleeve 8 on the external thread Id relative to the seat body 1.

In Fig. 1, the conical sleeve 7 and the setting sleeve 8 are connected to each other by means of an axially displaceable locking sleeve, indicated in its entirety by reference numeral 9. This locking sleeve has an inner toothing 9a which is connected to the respective outer teeth 7b, 8c of the conical sleeve 7 and the setting sleeve 8.

The connection of the setting sleeve 8 with the conical sleeve 7 takes place by means of a radially flexible locking ring 10 which is placed in the groove 8d in the setting sleeve 8 and retained in the annular groove 7a of the conical sleeve 7. A radially deformable elastic ring 11 is arranged in the retaining groove 7c of the conical sleeve 7. This elastic ring 11 interlocks with the grooves 9b, 9c of the locking sleeve 9, thus securing against accidental axial displacement at both end positions of the locking sleeve 9.

The clamping jaws, indicated by reference numeral 12, are mounted in a radially displaceable manner throughout the longitudinal slots 1e extending from the front end of the seat body 1. These clamping jaws 12 have a through hole 12a for an annular spring 13 which forces the clamping jaws 12 radially outwards against the inside of the conical sleeve 7. The non-rotating connection of the conical sleeve 7 with the seat piece 1 thus takes place via the clamping jaws 12. A labyrinth ring 14 is fitted at the motor end of the drill chuck. This labyrinth ring 14 prevents dust and debris from penetrating into the drill chuck as well as in the area of ​​the seals 5. To adjust the setting sleeve 8, its tool-side end is provided with a conical toothing 8b. The conical sleeve 7 has a receiving opening 7d for inserting a ring wrench known per se. The receiving opening 7d is preferably formed as an open longitudinal groove towards the rear end of the conical sleeve 7. Such a structure enables the economical manufacture of the conical sleeve 7 by casting. The ring wrench, not shown, thus rests on the conical sleeve 7 on three sides and on the setting sleeve 8 on the fourth side.

In the state shown in Fig. 1, the insertion head of the tool, indicated in its entirety by reference numeral 15, is inserted into the drill chuck. The insertion head 15 is provided with longitudinal grooves 15a into which the clamping jaws 12 interlock. However, this drill chuck can also be used to tighten tools with a smooth insert, only by friction. In the state shown in Fig. 1, the setting sleeve 8 is non-rotatably locked by means of a locking sleeve 9, a conical sleeve 7 and clamping jaws 12 with the seat piece 1. The receiving opening 7c for the ring gear and the conical teeth 8b is covered in the space shown in Fig. 1 by a locking sleeve 9, which thus also protects against dirt.

To change the tool, the locking sleeve 9 is pushed in the tool direction into the position shown in Fig. 2. In this case, the locking sleeve 9 is held in this position by means of the elastic ring 11 and the retaining groove 9c. The setting sleeve 8 is now rotatable relative to the seat piece 1 and the conical sleeve 7. By means of the threaded engagement of the setting sleeve 8 with the seat piece, the axial displacement of the conical sleeve 7 and thus the radial adjustment of the clamping jaws 12 takes place when the setting sleeve 8 is rotated. This setting of the setting sleeve 8 can take place manually or by means of a ring ring key which is inserted into the receiving opening 7d and which engages the bevel gear 8b. After setting the desired diameter, the locking sleeve 9 is pushed back into the position shown in Fig. 1 and thus the setting sleeve 8 is locked. In this case, the locking sleeve 9 is held in this end position by an elastic ring 11 interlocking in the groove 9b.