GB2432135A

GB2432135A - Locking unit for removable tool holder

Info

Publication number: GB2432135A
Application number: GB0622138A
Authority: GB
Inventors: Dietmar Saur
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2005-11-08
Filing date: 2006-11-06
Publication date: 2007-05-16
Anticipated expiration: 2026-11-06
Also published as: GB2432135B; GB0622138D0; CN1962202A; DE102005053137A1

Abstract

A hand machine tool locking unit for locking a removable tool holder 26 of a hand machine tool (10, fig 1) comprises a location sleeve 34 for receiving at least one locking element 40, 42 and an actuating sleeve 28 for actuating the locking element 40, 42. The location sleeve 34 has at least one location chamber 58 for receiving the at least one locking element 42 that is at least substantially closed radially outwards in a peripheral direction. The hand machine tool may be a hammer drill.

Description

ROBERT BOSCH GMBH; D-70442 Stuttgart Hand tool machine locking unit

Background art

The invention proceeds from a hand tool machine locking unit for locking a removable tool holder of a hand tool machine according to the preamble of claim 1.

From DE 103 21 869 Al a locking unit for locking a removable tool holder to a hammer drill is known. This comprises locking elements, a location sleeve, in which the locking elements are disposed, and an axially displaceable actuating sleeve for actuating the locking elements, by means of which actuating sleeve the tool holder may be released.

Advantages of the invention The invention proceeds from a hand tool machine locking unit for locking a removable tool holder of a hand tool machine having a location sleeve for receiving at least one locking element and to an actuating sleeve for actuating the locking element.

It is proposed that the location sleeve has at least one location chamber for receiving the locking element that is at least substantially closed radially outwards in peripheral direction. By means of the location chamber an advantageous protection of the locking element, in particular from dirt and dust, may be achieved. By a location chamber that is at least substantially closed in peripheral direction is to be meant in particular a location chamber that is at least 50% and preferably at least 75% closed in peripheral direction.

It is moreover proposed that the location chamber is completely closed outwards in peripheral direction, thereby allowing a penetration of dirt and dust into the location chamber to be further reduced, in particular prevented.

What is more, an outwardly sealed space for a lubricant supply may advantageously be achieved.

When the location chamber has a wall sub-region that forms a guide face for guiding the actuating sleeve, it is advantageously possible to dispense with additional guide elements, thereby allowing a compact design of the hand tool machine locking unit to be achieved.

In a further form of construction of the invention, the location chamber has a substantially uniform wall thickness. By a "substantially uniform wall thickness of the location chamber" in the present context is to be meant a wall thickness of a wall forming the location chamber that has variations below 25%, preferably below 10% and particularly advantageously below 5% along the wall. This advantageously allows material and installation space to be saved and a compact design of the location chamber to be achieved.

The hand tool machine locking unit preferably has a radially inwardly directed projection in the region of the location chamber. This projection may advantageously be used to fasten the location sleeve to a hand tool machine.

This may be effected for example by the establishment of a positive connection in interaction with a fastening element of a drive spindle of the hand tool machine.

It is further proposed that the actuating sleeve has at least one region, which is of a double-walled design and comprises at least one wall portion that engages into the location sleeve. In this manner, large guide faces for guiding the locking element and a compact design may be achieved. What is more, tolerances for the guidance may advantageously be compensated.

When the hand tool machine locking unit has a support element, which is provided for supporting a locking element in axial direction and is constructed integrally with the wall portion, it is possible to dispense with additional components for supporting the locking element.

In an advantageous manner, the location sleeve and the actuating sleeve are provided for guiding the locking element. For this purpose, the location sleeve and the actuating sleeve preferably have in each case at least one face that is designed specially for guiding the locking element. In this way, particularly large guide faces may be achieved.

It is further proposed that the hand tool machine locking unit has an annular support element that is provided for supporting the actuating sleeve in the locked state in locking direction. In this manner, a supporting of the actuating sleeve over a large circumference may be achieved, with the result that good retention and a low surface pressure on the support element may be achieved.

The unlocking direction is the direction, in which the actuating sleeve is moved to unlock the tool holder, and the locking direction is the opposite direction to the unlocking direction.

When the support element is manufactured from metal, a rugged support of the actuating sleeve may be achieved.

In a further construction of the invention, it is proposed that the location sleeve has at least one location means for receiving the support element. A locking force exerted on the support element may therefore advantageously be diverted onto the location sleeve.

Drawings Further advantages emerge from the following description of drawings. In the drawings an embodiment of the invention is represented. The drawings, description and claims contain numerous features in combination. The person skilled in the art will advantageously also consider the features individually and combine them into meaningful further combinations.

The drawings show: Fig. 1 a hand tool machine with a drive spindle, a hand tool machine locking unit, and a tool holder locked to the drive spindle, Fig. 2 the tool holder, the hand tool machine locking unit and the drive spindle in a perspective view, Fig. 3 the arrangement of Figure 2 in a side view, and Fig. 4 a location sleeve of the hand tool machine locking unit.

Description of the embodiment

Figure 1 shows a side view of a hand tool machine 10 in the form of a hammer drill. It comprises a housing 12, a drive spindle 16 oriented in axial direction 14, a drive unit 18, and a removable tool holding fixture 20, which is locked by means of a locking unit 22 to the drive spindle 16. The tool holding fixture 20 comprises a sleeve 24 and a tool holder 26.

In Figure 2 the spindle region of the hand tool machine 10 is represented in a perspective view. This shows the drive spindle 16, the tool holder 26 in the locked state, and the locking unit 22. This comprises an actuating sleeve 28.

An operator may unlock the tool holder 26 by means of a sliding movement of the actuating sleeve 28 in unlocking direction 30. The locking and/or unlocking mechanism is described with reference to Figure 3. At its outer region the actuating sleeve 28 is designed with a step 32.

Alternatively, the actuating sleeve 28 may have a recessed handle and/or further actuating elements deemed meaningful by the person skilled in the art. The locking unit 22 moreover comprises a location sleeve 34, three ends 34.1, 34.2, 34.3 of which are visible in the drawing. This location sleeve 34 is provided for receiving locking elements, which are represented in Figure 3. Also visible are an annular support element 36, designed as a retaining ring, of the locking unit 22 and a further retaining ring 37, the function of which is described with reference to Figure 3.

In Figure 3 the arrangement of the tool holder 26, the locking unit 22 and the drive spindle 16 is represented in a sectional view in the locked state of the tool holder 26.

For locking and unlocking the tool holder 26, locking elements 38, 40, 42 are provided. The locking elements 38 take the form of locking balls of the tool holder 26, which are latched in a recess 44 of the drive spindle 16. The locking element 40 is formed by a locking ring, which holds the locking elements 38 in their blocking position and hence prevents removal of the tool holder 26. To allow an unlocking of the tool holder 26, the locking element 40 may be moved along a guide face 46 of the tool holder 26 by sliding the actuating sleeve 28 in unlocking direction 30, wherein the locking elements 38 and hence the tool holder 26 are released. Finally, the locking element 42 takes the form of a spring. This spring holds the locking element 40 in the position, in which it blocks the locking elements 38, namely by means of a resetting force in a locking direction 48 that is opposite to the unlocking direction 30. To prevent the locking elements 38 from falling out when in the unlocked state, the retaining ring 37 is moreover provided. During mounting of the tool holder 26 onto the drive spindle 16, the tool holder 26 is guided into a centred position by means of two guide faces 52, 54 of the drive spindle 16. These are external faces of two regions of the drive spindle 16 that are spatially separate from one another and/or disposed on either side of the recess 44 and have different diameters.

The locking element 42 in the form of a spring is supported in a biased state at one end against the locking element 40 and at the other end against a wall 56 of the location sleeve 34. This wall 56 forms a location chamber 58, in which the locking element 42 is accommodated. As may be seen in Figure 4, the location chamber 58 is closed radially outwards in peripheral direction of the location sleeve 34, thereby affording advantageous protection against a penetration of dust into the location sleeve 34.

The wall 56 has a uniform wall thickness. The locking unit 22 further comprises a projection 60, which is moulded onto the wall 56 and directed radially inwards. This projection 60 is snapped into a location region 62 of the drive spindle 16 that is delimited by a shoulder 63 of the drive spindle 16 and by a ring 64. By said means the location sleeve 34 is fastened in axial direction 14 to the drive spindle 16. The ring 64 secures the projection 60 in the latched position thereof. The location chamber 58 moreover has a wall sub-region 66, which forms a guide face that is used to guide the actuating sleeve 28. In the drawing a further guide face 68 of the location sleeve 34 may be seen, by means of which the actuating sleeve 28 is guided during a movement in unlocking direction 30 and locking direction 48. The location sleeve 34 takes the form of a plastic part and may be manufactured easily e.g. by injection moulding. It is alternatively conceivable to design the location sleeve 34 as a metal part that may be manufactured e.g. by means of a casting or forming technique.

The actuating sleeve 28 further has a double-walled region 70. This comprises a wall portion 72, which engages into the location sleeve 34. The wall portion 72 extends in axial direction 14 and has a guide face 74, by means of which the locking element 40 is supported in radial direction and guided in unlocking direction 30 and locking direction 48. The locking element 40 is moreover supported in radial direction and guided during a movement in unlocking direction 30 and locking direction 48 by a guide face 76 of the location sleeve 34. For supporting the locking element 40 in axial direction 14 and guiding the locking element 40 in unlocking direction 30, the locking unit 22 is provided with a support element 78, which takes the form of a projection of the wall portion 72. The actuating sleeve 28 is moreover supported in locking direction 48 by a further wall portion 80 on the annular support element 36, with the result that the actuating sleeve 28 in the locked state is fixed in axial direction 14. The support element 36, which is manufactured from metal and is elastically deformable, is supported by the location sleeve 34 in location means 84.1, 84.2, 84.3 (Figure 4) . During a sliding movement of the actuating sleeve 28 in unlocking direction 30, the actuating sleeve 28 is arrested as a result of the wall portion 72 striking against the wall 56 of the location chamber 58.

In Figure 4 the location sleeve 34 is represented separately in a perspective view. This has three webs 82.1, 82.2, 82.3, between which the actuating sleeve 28 engages with the double-walled region 70 and two further identical double-walled regions into the location sleeve 34. It is possible to see the annular location chamber 58 for receiving the locking element 42. For receiving the annular support element 36, the location sleeve 34 is provided with location means 84.1, 84.2, 84.3, which take the form of collars formed in each case by a projection. Each projection is integrally moulded on one of the webs 82.1, 82.2, 82.3 and extends in radial direction.

For assembly of the locking unit 22, first the location sleeve 34 is fastened to the drive spindle 16. In said case, the projection 60 of the wall 56 latches into the location region 62 of the drive spindle 16. The locking elements 40, 42 are then fitted into the location sleeve 34. In said case, the locking element 42 in the form of a spring is received into the location chamber 58. Then, the actuating sleeve 28 is slipped in unlocking direction 30 onto the webs 82.1, 82.2, 82.3 of the location sleeve 34, wherein the locking element 40 is pressed onto the locking element 42. The annular support element 36 is finally slipped, biased outwards in radial direction, onto the ends 34.1, 34.2, 34.3 until it latches into the location means 84.1, 84.2, 84.3. After latching, the support element 36 lies in a biased state in the location means 84.1, 84.2, 84.3.

ROBERT BOSCH GMBH; 70442 Stuttgart Reference characters hand tool machine 52 guide face 12 housing 54 guide face 14 axial direction 56 wall 16 drive spindle 58 location chamber 18 drive unit 60 projection tool holding fixture 62 location region 22 locking unit 63 shoulder 24 sleeve 64 ring 26 tool holder 66 wall sub-region 28 actuating sleeve 68 guide face unlocking direction 70 region 32 step 72 wall portion 34 location sleeve 74 guide face 34.1 end 76 guide face 34.2 end 78 support element 34.3 end 80 wall portion 36 support element 82.1 web 37 retaining ring 82.2 web 38 locking element 82.3 web locking element 84.1 location means 42 locking element 84.2 location means 44 recess 84.3 location means 46 guide face 48 locking direction

Claims

ROBERT BOSCH GMBH; D-70442 Stuttgart Clims 1. Hand tool machine locking

unit for locking a removable tool holder (26) having a location sleeve (34) for receiving at least one locking element (40, 42) and having an actuating sleeve (28) for actuating the locking element (40, 42), characterized in that the location sleeve (34) has at least one location chamber (58) for receiving the locking element (42) that is at least substantially closed radially outwards in peripheral direction.

2. Hand tool machine locking unit according to claim 1, characterized in that the location chamber (58) is completely closed radially outwards in peripheral direction.

3. Hand tool machine locking unit according to claim 1 or 2, characterized in that a wall sub-region (66) of the location chamber (58) forms a guide face for guiding the actuating sleeve (28) 4. Hand tool machine locking unit according to one of the preceding claims, characterized in that the location chamber (58) has a substantially uniform wall thickness.

5. Hand tool machine locking unit according to one of the preceding claims, characterized by a radially inwardly directed projection (60) in the region of the location chamber (58) 6. Hand tool machine locking unit according to the preamble of claim 1 and in particular according to one of the preceding claims, characterized in that the actuating sleeve (28) has at least one region (70), which is of a double-walled design and comprises at least one wall portion (72) that engages into the location sleeve (34) 7. Hand tool machine locking unit according to claim 6, characterized by a support element (78), which is provided for supporting a locking element (40) in axial direction and is constructed integrally with the wall portion (72) 8. Hand tool machine locking unit according to claim 6 or 7, characterized in that the location sleeve (34) and the actuating sleeve (28) are provided for guiding the locking element (40) 9. Hand tool machine locking unit according to the preamble of claim 1 and in particular according to one of the preceding claims, characterized by an annular support element (36), which is provided for supporting the actuating sleeve (28) in the locked state in locking direction (48) 10. Hand tool machine locking unit according to claim 9, characterized in that the support element (36) is manufactured from metal.

11. Hand tool machine locking unit according to claim 9 or 10, characterized in that the location sleeve (34) has at least one location means (84.1, 84.2, 84.3) for receiving the support element (36) 12. Hand tool machine having a hand tool machine locking unit for locking a removable tool holder (26) having a location sleeve (34) for receiving at least one locking element (40, 42) and having an actuating sleeve (28) for actuating the locking element (40, 42) in particular according to one of the preceding claims, characterized in that the location sleeve (34) has at least one location chamber (58) for receiving the locking element (42) that is at least substantially closed radially outwards in peripheral direction.

13. A hand tool machine locking unit substantially as herein described with reference to the accompanying drawings.

14. A hand tool machine substantially as herein described with reference to the accompanying drawings.