WO2006008140A1

WO2006008140A1 - Handgrip for a hand tool

Info

Publication number: WO2006008140A1
Application number: PCT/EP2005/007865
Authority: WO
Inventors: Richárd FORIZS
Original assignee: Robert Bosch Gmbh
Priority date: 2004-07-16
Filing date: 2005-07-15
Publication date: 2006-01-26
Also published as: NL1026669C2; RU2007105738A; CN1976783A; EP1768820A1; RU2366565C2

Abstract

The present invention relates to a handgrip (15) for holding an electric hand tool (1), comprising a holder (17) and an engaging component (20, 30, 40, 50, 60) which is to be arranged in the holder and with which an active element (9) can be fastened to and released from the tool, wherein the engaging component can be placed in a storage position with a relatively small length to enable the engaging component to be stored in the holder, and in an active position with a relatively great length to enable the active element to be fastened and released with the engaging component. The invention also relates to a hand tool provided with such a handgrip.

Description

HANDGRIP FOR A HAND TOOL

The present invention relates to a handgrip for holding an electric hand tool, which handgrip is provided with an engaging unit for fastening an active element to the hand tool and releasing thereof from the hand tool . The invention also relates to a hand tool provided with such a handgrip. An electric hand tool, such as for instance a right-angle grinder, is provided with an exchangeable active element, also referred to as accessory, with which a determined operation can be carried out. In the example of a right-angle grinder the active element is an exchangeable grinding disc with which a workpiece can be ground. After a determined number of operations the active element requires replacement and must therefore be exchanged, which means that the user disconnects the active element from the tool and then arranges a new active element. In order to fasten such an active element firmly enough to the hand tool use is made of a special key supplied therewith. Such a key or engaging component can engage on the active element or at least on a fastening component with which the active element is fastened to the tool, so that the user can exert sufficient force to release the worn active element from the tool and fasten a new active element. Such keys do however tend to get lost in the course of time, whereby the active element can no longer be exchanged.

In order to avoid the key being lost it is known to store the key in the tool. Hand tools are thus known wherein the key can be stored in a handgrip of the hand tool. A drawback of the known tools is however that, in order to keep the tool manageable, the handgrip must have a limited length whereby the handgrip becomes too short to enable a key of sufficient length to be accommodated. The key must after all be long enough to be able to exert a sufficient torque to fix the active element to the hand tool.

A hand tool is known from German patent application DE 198 54 468 Al which is provided with a handgrip, which does have a length which is smaller than the minimal key length required for exerting a desired torque, but in which the key can slide out of the handgrip, whereby the length of the key is as it were extended by at least a part of the length of the handgrip. The handgrip must however always be detached here from the hand tool . A drawback of the known tool is that the key always remains attached to the handgrip, so that the user must remove the handgrip from the tool each time he/she wishes to use the key. When the active element must be exchanged repeatedly, for instance when different active elements are required for different operations, the handgrip must be detached each time, which results in an increase in change-over time. For operations for which the use of the key is convenient but for which little torque need be applied, and for which the length of the key is therefore less important, the handgrip must also be detached, which is time-consuming.

A further drawback of the known construction is that the outer end of the handgrip along which the key slides outward must be given a relatively heavy form at the position of this outer end in view of the great forces occurring there. The opposite end of the handgrip must also be given a heavy form because the coupling to the tool takes place there. Finally, at the position of the opposite end part, the known embodiment of the handgrip is provided with a projecting part, which is difficult for the user to take hold of during tightening and loosening of the active element.

It is an object of the present invention to provide an improved handgrip and an improved engaging component, wherein one or more of the above stated drawbacks associated with the prior art are obviated.

For this purpose there is provided a handgrip for holding an electric hand tool, which handgrip comprises: - a holder;

- an engaging component which is to be arranged in the holder and with which an active element can be fastened to and released from the tool, wherein the engaging component can be placed in a storage position with a relatively small length to enable the engaging component to be stored in the holder, and in an active position with a relatively great length to enable the active element to be fastened and released with the engaging component.

The engaging component is releasable from the handgrip, so that this latter need not be removed when the user wishes to apply the engaging component for operations requiring relatively little force. In the storage position the engaging component has a relatively small length, so that it can be stored in the holder of the handgrip. In the active position the length of the engaging component is so great that a sufficiently high torque can be developed therewith.

In a preferred embodiment, the holder is formed by a cavity which is provided in the handgrip and in which the engaging component can be received in its storage position. This embodiment is compact, robust and easy to manufacture. According to a further preferred embodiment, the engaging component is embodied to engage in the active situation on a fastening component with which the active component can be fastened to the hand tool, and to apply a torque to the fastening component. In this embodiment the active component is coupled to the hand tool by means of a fastening component, such as for instance a mounting flange or nut. The engaging component engages on the fastening component, and by applying a suitable torque the fastening component, and thereby the active element, can be tightened respectively loosened.

In a further preferred embodiment, the engaging component comprises at least two protrusions, preferably in the form of two protrusions which protrude from the engaging component and which can slide fittingly into corresponding openings in the fastening component so that the required torque is applied to the fastening component.

In a further preferred embodiment, the engaging component comprises a first strip-like component which is provided with at least two protrusions, and a second strip- like component which is arranged on the first component and which is displaceable in longitudinal direction between the active position, with relatively great length, and the storage position with a relatively small length. When situated in its storage position, this engaging component can herein be stored in the cavity in the handgrip. When the active element is exchanged, the engaging component is released from the handgrip and the first strip-like component is displaced in longitudinal direction such that the combined length of the two components becomes sufficiently great to enable a suitable torque to be applied to the fastening component. In another preferred embodiment, the engaging component comprises :

- a first elongate component which is provided with the protrusions; - a second elongate component;

- a hinge provided between the first and second component and extending substantially in the plane of the operating force, wherein the second component is pivotable between the storage position with relatively small length and the active position with relatively great length. In this embodiment the engaging component can be pivoted outward from the storage position, in which the two elongate components are stacked one on top of the other, into the active, pivoted position wherein both components extend mutually in line. In the active position the total length is roughly twice the length in the storage position. The components cannot be pivoted from the storage position further than said active position because end edges of the respective components provide the required stop. In a first embodiment the protrusions which can be placed fittingly in the openings of the fastening component are provided at two longitudinally offset positions on the first component . The advantage of this embodiment is that it is a narrow embodiment . In a variant it is however also possible to provide the protrusions at transversely offset positions on the first component. Although this embodiment is wider than the above described embodiment, the advantage is that a higher torque can be applied since the maximum achievable length of the engaging component, which is otherwise determined by the length of the holder, is practically equal to the length (arm) to which the force is applied. In yet another preferred embodiment, the engaging component comprises:

- a first elongate component which is provided on a first side as well as on the opposite side with the protrusions for respectively fastening and releasing the active element;

- a second elongate component;

- a hinge provided between the first and second component and extending substantially perpendicularly of the plane of the operating force, wherein the second component is pivotable between the storage position, with relatively small length, and the active position with relatively great length. In this embodiment the two components can also be pivoted from the storage position into the active position. In order to hold the components in the active position, there is provided on one of the two components a stop which consists of a flange or pin extending from the respective component.

In this embodiment the first component is provided on both sides with the protrusions fitting into the openings of the fastening component, wherein the protrusions on the one side are adapted for tightening the fastening component, while the protrusions on the other side are adapted for loosening of the fastening component. In another preferred embodiment, the engaging component comprises:

- a first elongate component which is provided with protrusions for fastening and releasing the active element;

- a second elongate component; - a hinge provided between the first and second component and extending substantially perpendicularly of the plane of the operating force, wherein the second component is pivotable between the storage position, with relatively small length, and the active position with relatively great length;

- a lock for fixing the first and second elongate component in the active position relative to each other. So as to avoid the use of protrusions on both sides of the component, as is the case in the first described embodiment, there is provided in this embodiment a lock with which both elongate components can be fixed in the active position. In this embodiment the total length in the active position is also practically twice the length in the storage position.

In the above stated embodiments the handgrip can be arranged permanently or releasably on the hand tool. In the embodiment to be discussed hereinbelow however, the handgrip comprises an end part on which handgrip fastening means are provided, for instance in the form of an outer end provided with a screw thread, so that the handgrip can be released in simple manner from the hand tool . In a particularly advantageous embodiment, the engaging component is integrated with the handgrip. The engaging component is herein provided with first fastening means for fastening the engaging component to a first end part of the handgrip when the engaging component is received in the holder, as well as second fastening means for fastening the engaging component to the handgrip fastening means provided on the opposite end part. The length of the integrated engaging component in the storage position is smaller than the length in the active position. During normal use the engaging component is therefore situated in the holder, formed by a cavity, of the handgrip and is fastened thereto with first fastening means. When the active element is being replaced, the user removes the engaging component from the handgrip via a first outer end, whereafter he/she fastens the engaging component to the opposite end part of the handgrip. In this case the engaging component is therefore arranged on that part of the handgrip which is already embodied sturdily, i.e. on that end with which the handgrip is attached to the hand tool normally, i.e. when the machine is in operation. The engaging component thus placed in the active position can further be taken hold of by the user at the position where he/she would also grasp the handgrip when the machine is in operation. Further advantages, features and details of the present invention will be elucidated on the basis of the following description of several preferred embodiments thereof. In the figures:

Fig. 1 shows an exploded perspective view of a right-angle grinder which is provided with a first preferred embodiment of the handgrip according to the invention;

Fig. 2 shows a perspective view of a first preferred embodiment of an engaging component, in the storage position (full lines) and in the active position (broken lines) ;

Fig. 3 shows a perspective view of a second and a third preferred embodiment of an engaging component in the active position; Fig. 4 shows a perspective view of a fourth preferred embodiment of the engaging component in active position;

Fig. 5a is a perspective view of a fifth preferred embodiment in storage position; Fig. 5b is a perspective view of the fifth preferred embodiment in active position; Fig. 6a - 6b are perspective views of a sixth preferred embodiment of an engaging component, at diverse stages between the storage position and active position. Fig. 1 shows an exploded view of a right-angle grinder 1. Grinder 1 comprises a housing 2 in which is arranged an electric motor (not shown) . The electric motor can be switched on and off using operating switch 3 placed in the wall of the housing, and drives a tool shaft 4 in known manner via a transmission arranged in the housing. The part of tool shaft 4 protruding on the outside of housing 2 comprises inter alia a shaped part 5. A first fastening part 7 can be arranged over shaped part 5. The first fastening part 7 is provided in the centre with an opening 8 with an internal shape corresponding to the external shape of shaped part 5, so that the first fastening part 7 can be arranged fittingly over shaped part 5 and co-displaces with the rotation of the tool shaft. In the shown embodiment the shaped part 5 and opening 8 have an elongate form, but other shapes can of course also be envisaged. The thickness of shaped part 5 corresponds to or is smaller than the thickness of the first fastening part 7, so that an accessory 12, such as a grinding disc, can be arranged closely against shaped part 5 and the first fastening part 7 on the outward facing side of the first fastening part 7. For this purpose the accessory 12 is provided with a central opening 13 having a diameter which is slightly greater than that of end part 6 of shaft 4. Accessory 12 is clamped fixedly between the first fastening part 7 and a second fastening part 9. Arranged for this purpose in the centre of the second fastening part 9 is a central opening 10 which is provided with internal screw thread 11. The internal screw thread 11 can engage on the external screw thread 12 provided on the outer end 6 of tool shaft 4. The second fastening part 9 can thus be tightened onto shaft 4. In order to screw the second fastening part with sufficient clamping force against accessory 12, the second fastening part 9 is provided with a pair of openings 14 or a pair of openings 14 ' in which can engage pins of a key to be described below. Using the key a high torque can be applied to the first fastening part 7 such that the grinding disc is clamped sufficiently firmly between the first and second fastening part. Using the key a sufficient torque can likewise be applied to the second fastening part 9 for loosening thereof again in the opposite direction of rotation.

Two pairs of openings 14, 14' are provided in the shown embodiment. More or fewer openings can however be provided in other embodiments. It is also possible to ensure engagement of the key on the second fastening part in other ways, for instance by having the key engage on a second fastening part with a polygonal outer periphery. In order to enable a firm grip on housing 2 of right-angle grinder 1 during grinding, the right-angle grinder 1 is provided with a handgrip 15 arranged on housing 2. Handgrip 15 consists of a formed part 16 which is shaped for holding by the hand of a user, and a flange 19 for protection of the hand. Handgrip 15 is provided with a cavity 17 in which the above mentioned key can be received. Cavity 17 can be closed off with a screw cap 18. During grinding the key is held in cavity 17 so that it cannot be lost. When however an accessory 12 must be replaced, the user unscrews cap 18 from handgrip 15 and removes the key from cavity 17. Figures 2-5 show several preferred embodiments of keys according to the invention.

Fig. 2 shows a first preferred embodiment in which key 30 is constructed from a lower elongate steel strip 31 and an upper elongate steel strip 32. Upper strip 32 is provided with an elongate slot 36 in which pins 33 and 34 are arranged displaceably. Pins 33 and 34 are fixed on one side to lower strip 31 and have a projecting end part on the other, so that upper strip 32 remains enclosed between lower strip 31 and the projecting end parts. Strip 32 is displaceable in longitudinal direction (P₁) along lower strip 31, so that the original length L of key 30 can be increased from the starting position (shown in full lines) to an active position with end length L' in an end position (shown in partly broken lines) . In the storage position the key 30 has a length L which is smaller than the length of cavity 17 in handgrip 15, so that the key can be stored therein. In its end position or active position the key 30 has a greater length L' , which is sufficient for a user to apply a sufficiently high torque on the second fastening component 9 (Fig. 1) .

Placed for this purpose on the underside of strip 31 are two pins 35 which have a form and mutual distance such that they fit inside two corresponding openings 14 or

14' in the second fastening part 9. When an operating person takes hold of the key at the position of outer end 39 of strip 32, a sufficiently long arm, and thereby a sufficiently high torque, is provided in the active position to clamp the second fastening part 9 sufficiently tightly using pins 35 or to unscrew an fastening part 9 once it has been clamped.

Fig. 3 shows a second preferred embodiment of a key 40 according to the invention. In this embodiment key 40 comprises a first key part 41 and a second key part 42, which parts 41, 42 can pivot mutually in the plane of the operating force by means of a hinge 44. Arranged once again on one side of the first key part 41 are pins 45 which fit inside openings 14 or openings 14 ' of the second fastening part 9. In the shown embodiment the key 40 has the maximum length. At this length a user who takes hold of key 40 close to outer end 49 of the second fastening part 42 can apply a sufficiently high torque on the second fastening part 9 using pins 45. Key 40 can further be pivoted in the direction of arrow P₂ to a length L, which is roughly half the length L' in the outward pivoted situation. In the folded-up situation key 40 can therefore be easily stored in cavity 17 of handgrip 15.

Fig. 3 shows with a dotted line that, instead of two pins 45 extending in longitudinal direction, the outer end 43 of key part 41 can be embodied such that pins 45 ' extend in width direction. A higher torque can also be applied to the second fastening part 9 with this alternative embodiment in that the length (arm) is greater between the point of engagement of the force and the point of rotation. The pins can of course also extend in a direction lying between the two shown directions. Fig. 4 shows a fourth preferred embodiment of a key 50 according to the invention, wherein a first key part 51 and a second key part 52 are arranged on each other by means of a hinge 54. Instead of a hinge in the plane of the operating force as in the embodiment of Fig. 3, in this embodiment hinge 54 is at right angles to the plane of the operating force. In order to fix key 50 in the outward pivoted active position shown in Fig. 4, there is therefore arranged on the first key part 51 a pin 56 which, together with a longitudinal edge of end part 58 of the second key part 52, ensures that when an operating person grips end part 57 of the second key part 52 and exerts force in the direction of arrow P₄, key 50 remains in the active position. Pins 55' provided on the underside of the first key part 51 serve for tightening of the second fastening part 9 in clockwise direction, while the pins 55 provided on the upper side of the first key part 51 serve for loosening of the second operating part 9. The length L of key 50 in the outward pivoted position can again be greatly reduced to a length L' in storage position by rotating end part 57 of the second key part 52 in the direction P₃.

Fig. 5a and 5b show a further preferred embodiment of a key 60 according to the invention. Key 60 consists once again of a first key part 61 and a second key part 62. The first key part 61 is provided with two pins 65 which fit into openings 14 of the second fastening component 9. The first and second key parts 61 and 62 are pivotable by means of a hinge 64, which hinge extends substantially at right angles to the plane of the operating force. Fig. 5b shows key 60 in active position. In this position a lock is arranged over the first and second key parts such that they remain fixed mutually in line. In this position a sufficient torque can be transmitted to the second fastening component 9 by pins 65 by engaging end part 67 of the second key part 62. In order to fold up the key 60, lock 63 is shifted in the direction of arrow P₁ of the key parts, the first key part 61 is rotated in the direction of arrow P₅ and lock 63 is again arranged so that the end position shown in Fig. 5b is reached. In the active position of figure 5b the length L' is about twice the original length L, so that the key 60 shown in figure 5b can be stored in simple manner in handgrip 15.

Fig. 6a - 6c show a further preferred embodiment in which the key is integrated with handgrip 15. Handgrip

15 is here embodied releasably from housing 2 of hand tool 1. In the shown embodiment the key 20 comprises for this purpose the above mentioned handgrip 15 as first key part and, as second key part, the separate part 21 to be received partly in cavity 17 of handgrip 15. Fig. 6a shows the situation wherein the second key part 21 has been removed from cavity 17. During operation however, the second key part 21 will be partially received in cavity 17 by screwing a cap 23 provided with an external screw thread 24 onto end part 26 of handgrip 15 provided with screw thread 25. Fixed once again to cap 23 is an elongate strip 22, on one side of which are provided the above stated pins 25 which are embodied to be able to engage in openings 14 or 14 ' in the second fastening component 9.

As stated above, Figure 6a shows the position wherein the second key part 21 is released from the first key part or handgrip 15. Figure 6b shows that the second key part 21 is fastened to the opposite end 27 of handgrip 15. The opposite end 27 of handgrip 15 comprises the above mentioned flange 19 as well as a fastening component such as the threaded end 28 in the shown embodiment. This threaded end 28 has on the one hand the function of providing an fastening option for handgrip 15 in a corresponding opening (not shown) in housing 2 of hand tool 1 when the tool is in operation, i.e. for instance during grinding, and on the other hand a fastening option for the second key part 21. The second key part 21 is provided for this purpose with an opening 29 which is provided with screw thread and embodied such that the second key part 21 can be screwed fixedly onto threaded end 28 of handgrip 15 (Fig. 6c) . In the situation shown in figure 6c the user can now comfortably grip key 20 at the position where the user normally takes hold of handgrip 15, i.e. on the part 16 thereof, so that a high torque can be applied to the second fastening part 9 of hand tool 1 by means of pins 25. In the shown embodiment the end part 26 of handgrip 15 can be given a relatively light form since the greatest forces are exerted on end part 27 of handgrip 15 both in the normal situation in which the handgrip is used to hold hand tool 1 and in the situation in which handgrip 15 is used as component of a key 20. No additional structural provisions need therefore be made to make the detachable handgrip 15 suitable to be able to function as component of a key. An embodiment of key part 21 which can be extended in the ways shown in figures 3-5, wherein an even higher torque can be applied, is of course also possible.

The rights sought are not limited to the preferred embodiments of the invention described herein, but by the following claims, within the scope of which many modifications can be envisaged.

Claims

1. Handgrip for holding an electric hand tool, comprising: - a holder;

2. Handgrip as claimed in claim 1, wherein the holder is formed by a cavity which is provided in the handgrip and in which the engaging component can be received in its storage position.

3. Handgrip as claimed in claim 1 or 2, wherein the engaging component is embodied to be able to engage in the active situation on a fastening component with which the active component can be fastened to the hand tool, and to apply a torque to the fastening component.

4. Handgrip as claimed in claim 3, wherein the engaging component comprises at least two protrusions, preferably pin-like protrusions, which fit inside corresponding openings in the fastening component in order to tighten the fastening component to and release it from the hand tool .

5. Handgrip as claimed in claim 4, wherein the engaging component comprises:

- a first strip-like component which is provided with the protrusions; - a second strip-like component which is arranged on the first component and which is displaceable in longitudinal direction between the active position, with relatively great length, and the storage position with a relatively small length.

6. Handgrip as claimed in claim 5, wherein the first or second strip-like component is provided with an elongate opening and the other strip-like component is provided with at least one pin which is slidable in the opening and with which the strip-like components are fixed to each other.

7. Handgrip as claimed in claim 4, wherein the engaging component comprises:

- a first elongate component which is provided with the protrusions;

- a second elongate component;

- a hinge provided between the first and second component and extending substantially in the plane of the operating force, wherein the second component is pivotable between the storage position with relatively small length and the active position with relatively great length.

8. Handgrip as claimed in claim 7, wherein the stop for holding the engaging component in the active position is formed by the respective end edge of the first and second elongate component.

9. Handgrip as claimed in claim 8, wherein the protrusions are provided at longitudinally offset positions on the first component.

10. Handgrip as claimed in claim 8, wherein the protrusions are provided at transversely offset positions on the first component.

11. Handgrip as claimed in claim 4, wherein the engaging component comprises: - a first elongate component which is provided on a first side as well as on the opposite side with the protrusions for respectively fastening and releasing the active element; - a second elongate component;

- a hinge arranged between the first and second component and extending substantially perpendicularly of the plane of the operating force, wherein the second component is pivotable between the storage position, with relatively small length, and the active position with relatively great length.

12. Handgrip as claimed in claim 11, wherein the stop for holding the engaging component in the active position is formed by a stop component protruding from one of the elongate components.

13. Handgrip as claimed in claim 4, wherein the engaging component comprises:

- a first elongate component which is provided with the protrusions for fastening and releasing the active element;

- a second elongate component;

- a hinge arranged between the first and second component and extending substantially perpendicularly of the plane of the operating force, wherein the second component is pivotable between the storage position, with relatively small length, and the active position with relatively great length;

- a lock for fixing the first and second elongate components in the active position relative to each other.

14. Handgrip as claimed in claim 4, wherein the handgrip comprises an end part on which handgrip fastening means are provided for releasable fastening of the handgrip to the hand tool.

15. Handgrip as claimed in claims 3 and 14, comprising an engaging component integrated with the handgrip, wherein the engaging component is provided with first fastening means for fastening the engaging component to a first end part of the handgrip when the engaging component is received in the cavity, as well as with second fastening means for fastening the engaging component to the handgrip fastening means provided on the opposite end part.

16. Handgrip as claimed in claim 15, wherein the length of the integrated engaging component in the storage position is smaller than the length in the active position.

17. Handgrip as claimed in claim 15 or 16, wherein the first fastening means comprise a screw cap which can be screwed fixedly onto the first end part.

18. Handgrip as claimed in claim 15, 16 or 17, wherein the second fastening means comprise screw thread with which the engaging component can be screwed fixedly to the handgrip fastening means.

19. Handgrip as claimed in any of the foregoing claims, wherein the hand tool is a right-angle grinder and the active element is a grinding disc.

20. Hand tool provided with a handgrip as claimed in any of the foregoing claims.

21. Engaging component evidently intended for a handgrip as claimed in any of the claims 1-19.