GB2448058A

GB2448058A - Handle with telescopic damping element

Info

Publication number: GB2448058A
Application number: GB0805426A
Authority: GB
Inventors: Roswitha Eicher; Stefan Heess; Joerg Maute; Florian Esenwein; Bernhard Eicher; Marcus Schuller
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2007-03-29
Filing date: 2008-03-25
Publication date: 2008-10-01
Anticipated expiration: 2028-03-25
Also published as: GB2448058B; GB0805426D0

Abstract

A handle comprises a gripping element 10, a fastening element 20, and at least one telescopic damping element 30. The telescopic damping element 30 preferably comprises a piston 32 and cylinder 34 arrangement. This arrangement may comprise a plurality of pistons 32 and cylinders 34 arranged axially within the length of the gripping element 10, with a damping means 35 being provided between each piston-cylinder pair (figure 1). An additional second damping element (50, figure 5) acting in the radial direction may also be provided. Alternatively, the telescopic damping element 30 may comprise a number of radially arranged pistons 32 and cylinders 34 mounted around fastening element 20 in the form of a rod (figure 2). In alternative arrangements, the damping element 30 may be directly joined to the fastening element 20 and telescopically arranged within the gripping element 10 with damping means 34 provided therebetween (figure 3), or may be formed by the gripping element 10 being formed from telescopically arranged (piston 32/cylinder 34) individual gripping parts with damping means 34 provided therebetween (17, 18; figure 4).The handle is preferably an auxiliary handle for a power tool. The damping element 30 may be provided within a hollow gripping element 10 (as shown, plus figures 3 and 4), or may be provided with the housing of the power tool (figure 5).

Description

Description Title

Handle

Prior art

The invention relates to a handle, in particular an auxiliary handle, for a hand-held power tool according to the precharacterising clause of Claim 1.

Numerous electric tools, such as, for example, angle grinders, drilling machines and drilling hammers, are equipped with an auxiliary handle. To avoid transmission of vibrations, occurring during operation of the electric tool, to the operator via the auxiliary handle, auxiliary handles are in most case provided with vibration-damping means.

From DE 10 2004 017 761 Al there is known a vibration-damped handle having a rigid mounting part for releasable attachment at one end to a hand-held electric tool, and a gripping part. The mounting part extends into the gripping part, vibration-damped means being provided between the gripping part and the mounting part.

Disclosure of the invention

The invention starts from a handle which comprises a gripping element and a fastening element for releasable fastening of the handle to a housing of a hand-held power tool, and also at least one damping element for damping vibrations during operation of the hand-held power tool.

According to the invention, the handle has a telescope-like damping element as the damping element. The telescope-like damping element is referred to below, for simplification, also as the telescopic damping element. The telescopic damping element allows effective reduction of vibrations transmitted, during operation of a hand-held power tool, to the handle and hence to the user via the fastening element.

The telescopic damping element comprises in particular two or more telescopic elements which are mounted in the manner of a telescopic rod one inside the other. The telescopic damping element is constructed, in principle, in a manner similar to a hydraulic shock absorber, the telescopic damping element comprising in particular at least one cylinder and a piston displaceably mounted in the cylinder.

In the context of the present invention, the terms cylinder and piston describe mainly the function of these telescopic elements and do not restrict their geometrical shape in any way. For example, the cylinder and the piston may be of cylindrical shape, but they may also have another cross-sectional shape.

In a further refinement, the telescopic damping element comprises a plurality of cylinders connected in series, each two successive cylinders being connected by a displaceably mounted piston. The nesting of a plurality of cylinders and pistons one inside the other increases the damping action of the telescopic damping element. A plurality of cylinders and pistons connected in series allow improved vibration damping in that vibrations can be reduced stepwise.

The vibration damping is achieved in particular by virtue of the fact that the piston is mounted in the cylinder in a damping manner. The damping mounting is effected in particular by means of a damping means situated in the hollow space of the cylinder. If vibrations occur, the damping means situated in the cylinder brakes the movement of the piston in the cylinder. The damping mounting can be effected, in principle, in a manner similar to a hydraulic shock absorber by means of a gas cushion or a liquid cushion. The liquid may be in particular a comparatively highly viscous liquid, e.g. an oil or a gel. As an alternative to the principle of a hydraulic shock absorber, the damping mounting can also be effected in the manner of a solid shock absorber by means of an elastic element, in particular an elastomer, foam or the like.

Where there are a plurality of telescopic elements connected in series, with damping means therebetween, different damping means or identical damping means with different damping properties may also be employed.

Vibrations in the handle can thus be reduced in a specific manner. If, for example, gas cushions are provided as damping means, each gas cushion can be provided with a different gas pressure between a piston and a cylinder.

Alternatively, different elastic elements, e.g. elastomers with different elasticity, may be used as damping means.

In a special embodiment, the telescopic damping element may also be a hydraulic telescopic damper. The telescopic damper in this case comprises, in a manner known per se, a piston guided on a piston rod in a cylinder filled with a hydraulic liquid, e.g. oil. On axial movement of piston rod and cylinder relative to one another, the hydraulic liquid flows through narrow ducts, bores, valves or the like in the piston. The flow resistance and hence the damping action increases with the speed of the piston movement.

The telescope-like damping element according to the invention may be axially arranged in or on the handle, so that it displays its damping action in the axial direction.

It may, however, also be radially arranged in the handle, whereby a damping action takes place in the radial direction. A combination of an axially directed telescopic damping element and a radially directed telescopic damping element is also possible.

If the telescopic damping element is arranged in the handle in the axial direction, a second damping element may be provided, by means of which the telescopic damping element is mounted in a vibration-damping manner in the radial direction. For example, the cylinder carrying the piston may be mounted in a radially vibration-damping manner with respect to a receptacle for the cylinder by arranging elastic means, e.g. in the form of elastomeric material, between the outer surface of the cylinder and the inner surface of the receptacle. In particular, for example an 0-ring made of elastomeric material may be arranged around the cylinder. Alternatively, there may also be provided individual nub-shaped elastic means or rib-shaped elastic means which are oriented in the longitudinal direction between the cylinder and the receptacle.

The telescopic damping element may be arranged at different positions in the handle and connect two elements of the handle, e.g. the fastening element and the gripping element, to one another in a vibration-damping manner in different ways. In one embodiment, the fastening element is mounted in a vibration-damping manner with respect to the gripping element by means of the telescope-like damping element. In this case, the telescopic damping element may be arranged in the axial direction, so that the gripping element is connected to the fastening element in a vibration-damping manner via the telescopic damping element. This may be realised, in a specific embodiment, in such a way that the gripping element is formed as a gripping sleeve which is of hollow design in its interior.

The gripping sleeve may in this case be mounted in a vibration-damping manner with respect to the fastening element by means of the telescope-like damping element in that the telescopic damping element extends in the axial direction inside the gripping sleeve. For this, the telescopic damping element is suspended, on the one hand, on the fastening element and, on the other hand, on the gripping element. It may, for example, be integrally formed on the fastening element and/or the gripping element, but may also be attached to the fastening element and/or the nripoing element in some other way.

Alternatively, the telescopic damping element may be arranged in the radial direction in order to mount the fastening element in a vibration-damping manner in the radial direction with respect to the gripping element. This may be realised, for example, in that the fastening element projects in the shape of a rod into the gripping element and at least one piston is radially arranged in the gripping element on the fastening element, which piston is mounted radially displaceably in a cylinder arranged on the gripping element. The other way round, a cylinder may also be radially arranged on the fastening element projecting into the gripping element, and a piston radially arranged on the gripping element.

In a further embodiment, the telescopic damping element may also be arranged on the handle in such a way that, after attachment of the handle to a housing of a hand-held power tool, the telescopic damping element is arranged in the housing. In this case, the telescopic damping element may be arranged either on the housing of the hand-held power tool, the telescopic damping element having a receptacle for the fastening element of the handle, e.g. a receptacle with internal thread, so that a threaded fastening element may be screwed into the receptacle. Preferably, however, the telescopic damping element is connected to the fastening element, and hence to the handle. The fastening element in this case comprises a piston which is displaceably mounted in a cylinder. The cylinder is arranged in a receptacle, which may for example be provided with an external thread, in order to screw the receptacle together with the telescopic damping element into the housinq of a hand-held power tool. Accordingly, in this embodiment the fastening element is mounted in a vibration-damping manner with respect to the housing of the hand-held power tool by means of the telescopic damping element.

Furthermore, the gripping element may be constructed telescope-like in itself. In this case, the gripping element comprises, for example, a first sub-element which forms the cylinder, and a second sub-element which forms the piston. The gripping element may also be constructed from a plurality of sub-elements which are each mounted in a manner displaceable in the above-described form as pistons and cylinders, in particular in a damping manner, one inside the other. Insofar as the gripping element comprises a gripping sleeve, the gripping sleeve may analogously be constructed telescope-like in itself from at least two sub-elements.

In a further refinement, the gripping element comprises a gripping sleeve and a gripping core, the gripping sleeve being mounted in a vibration-damping manner with respect to the gripping core by means of the telescope-like damping element. In this case, the telescopic damping element is arranged in particular radially between gripping core and gripping sleeve.

The gripping element of the handle according to the invention has a substantially cylindrical shape. In a simple embodiment, this may be a cylinder. The cylindrical gripping element may also be adapted to the ergonomics of the human hand in that, differing from a pure cylinder shape, it has, for example, different diameters along its longitudinal axis and is thus of bulging or convex design.

In this case, the gripping element may be of rotationally symmetrical design, so that the handle can be gripped by the operator in any orientation. Alternatively, the gripping element may also be adapted so specifically to the ergonomics of the human hand that a first region of the gripping element serves specifically as a bearing surface for the palm of the hand and a second region as a bearing surface for the fingers.

The gripping element may, moreover, be constructed of one or more parts. A gripping element of more than one part comprises, for example, a gripping core and a gripping sleeve with possibly damping means therebetween. One or more parts of the gripping element may likewise be designed in a vibration-damping manner. Thus, for example, the gripping sleeve may be formed from an elastic material, e.g. an elastomer or a foam, or the gripping core may be formed as an absorption mass. The gripping element may also have a coating made of an elastic material.

The fastening element of the handle serves for releasable fastening to a housing of a hand-held power tool. In a simple embodiment, the fastening element may be a threaded bolt, a screw or the like. The handle can thus be screwed into the housing of the hand-held power tool. The other way round, the fastening element may be a kind of threaded nut or another form of a receptacle having an internal thread, a corresponding thread for fastening the handle being provided on the housing of the hand-held power tool.

Instead of a screwed device, a clamping device, for example, may also be provided as the fastening element for fastening the handle.

The ftning element may be made of one or more parts. A two-part fastening element comprises, for example, a fastening device and a support element, it being possible for the fastening device to be, for example, a screwed device, e.g. a threaded bolt, a screw or the like, or a clamping device. The fastening device is in this case arranged on the support element, for example by a support element made of plastic being injection-moulded partially around a threaded bolt. The support element for the fastening element forms the head of the handle and, when the handle is in the state mounted on the housing of a hand-held power tool, faces this housing.

The handle according to the invention is suitable in particular as an auxiliary handle for a battery-operated or mains-operated hand-held power tool, such as, for example, an angle grinder, drilling hammer. Accordingly, a hand-held power tool having a handle according to the invention forms a further subject-matter of the invention.

The invention is explained in more detail below with reference to the attached drawings, in which, in schematic illustrations, Figure 1 shows a first embodiment of a handle with axially arranged telescope-like damping element Figure 2 shows a second embodiment of a handle with radially arranged telescope-like damping element Figure 3 shows a third embodiment of a handle with telescope-like damping element between gripping element and fastening element Figure 4 shows a fourth embodiment of a handle with a gripping element telescope-like in itself Figure 5 shows a fifth embodiment of a handle with axially arranged telescope-like damping element in a housing of a hand-held power tool.

Fig. 1 schematically illustrates a handle 100 which is suitable, in particular, as an auxiliary handle for a hand-held power tool (partially illustrated in Fig. 5). The handle comprises a gripping element 10 which, in the illustrated embodiment, is of hollow design over its entire length. The hollow space is denoted by the reference symbol 11 in Fig. 1. The gripping element 10 is provided, at an end which faces the hand-held power tool when in the state mounted on the hand-held power tool, with a collar-like widening 13 which serves as a slip-off prevention means. At this end of the handle 100, a fastening element 20 projects from the gripping element 10. The fastening element 20 serves for attaching the handle 100 to a housing 40 of a hand-held power tool. The fastening element 20 according to Fig. 1 is, for example, a threaded bolt which is provided, at its end 21 projecting out of the gripping element 10, with a thread (not illustrated specifically) for attaching the handle 100 to the housing 40. The handle 100 can thus be screwed into the housing of a hand-held power tool.

Instead of a thread, a clamping device, for example, as is already known in principle from the prior art, may also be provided at the free end 21. The opposite end 22 of the fastening element 20 projects into the gripping element 10.

The fastening element 20 is mounted in the gripping element in a damping manner by means of a telescope-like damping element 30. It is supported on the gripping element 10 via the telescopic damping element 30. For this purpose, the telescopic damping element 30 extends in the hollow space 11 in the axial direction along the gripping element from the end 22 of the fastening element 20 projecting into the gripping element 10, as far as the end 12 of the gripping element 10 lying opposite the fastening element 20. The telescopic damping element 30 comprises, according to Fig. 1, a plurality of telescopic elements in the form of pistons 32 and cylinders 34 which are mounted in the manner of a telescopic rod one inside the other. The end 22 of the fastening element 20 projecting into the gripping element is formed as a first piston 32. In this case, the first piston 32 is integrally formed on the lower end 22 of the fastening element 20. Alternatively, the first piston 32 may, however, also be attached to the fastening element 20 in some other way (not illustrated) . The first piston 32 is mounted in a first cylinder 34 in a manner displaceable in the axial direction. The end of the cylinder 34 facing away from the first piston 32 at the same time forms a second pIston 32, which in turn is mounted in a displaceable and damping manner in a second cylinder 34. Analogously, on the end of the second cylinder 34 facing away from the second piston 32 is formed a third piston 32, which is received in a corresponding manner in a third cylinder 34. Finally, a further, fourth piston 32 is integrally formed on the end of the third cylinder 34 facing away from the third piston 32. This fourth piston 32 is displaceably mounted in a fourth cylinder 34. The fourth cylinder 34 is formed on the lower end 12 of the gripping element 10 by providing the gripping element 10, at its lower end 12, with a recess which forms the hollow space 33 of the cylinder 34. The pistons 32 are each mounted in a damping manner in the cylinders 34 by providing a damping means 35 in the hollow spaces 33 of the cylinders 34. The damping means 35 may be a fluid cushion, e.g. a gas cushion or a liquid cushion. It may, however, also be an elastic element, e.g. made of an elastomer or a foam. In Fig. 1, a solid damping means 35, in particular made of an elastomer or foam, is schematically illustrated between the second piston 32 and the second cylinder 34. When there are a plurality of pistons 32 and cylinders 34, identical or different damping means 35 may be employed.

Accordingly, in the embodiment according to Fig. 1, a plurality of cylinders 34 are connected in series, each two successive cylinders 34 being connected to one another by a displaceably mounted piston 32. The pistons 32 and cylinders 34 are each mounted in the manner of a telescopic rod one inside the other in a damping manner.

Furthermore, it can be gathered from Fig. 1 that the wall 14 of the gripping element JO is designed with a varying thickness in the axial direction in order to increase the stability of the gripping element 10, the wall thickness increasing towards the lower end 12.

Fig. 2 schematically shows an embodiment in which the gripping element 10 is likewise of hollow design and the fastening element 20 extends in the shape of a rod in the axial direction in the hollow space 11 of the gripping element 10. The fastening element 20 is in this case mounted in a vibration-damping manner with respect to the gripping element 10 by means of two telescope-like damping elementc 3fl. The telescopic damping elements 30 are arranged in the radial direction between fastening element and gripping element 10. According to Fig. 2, a telescopic damping element 30 comprises four pistons 32 arranged radially on the fastening element 20, and four cylinders 34 arranged radially inside the gripping element 10, the pistons 32 being displaceably mounted in the cylinders 34. Two each of the pistons 32 and cylinders 34 are arranged diametrically opposite one another, so that the movement of the pistons 32 in the cylinders 34 can take place in a communicating manner. In a similar manner to the embodiment described in Fig. 1, the pistons 32 are mounted in a damping manner in the cylinders 34 via damping means (not illustrated specifically in Fig. 2), such as, for example, gas cushions, liquid cushions or solid cushions.

In the enlarged detail according to Fig. 2a, it can be seen that the four pistons 32 are attached to the fastening element 20 radially in one plane via a ball-and-socket joint 36. The cylinders 34 are each received in corresponding recesses 16 in the inner wall 15 of the gripping element 10.

The embodiment of a telescope-like damping element illustrated in Fig. 2 can likewise be employed in a handle having a gripping element comprising a gripping sleeve and a gripping core mounted coaxially in the gripping slee.ve.

In this case, a telescopic damping element can likewise be arranged in the radial direction between gripping core and gripping sleeve.

Figs. 3 and 4 show, in a schematically simplifying manner, further possible arrangements of the telescopic damping element 30 for the vibration-damping mounting of one of the elements of the handle 100. Fig. 3 shows a telescope-like damping element 30 which is arranged in the head region 25 of the handle 100 axially between gripping element 10 and fastening element 20. For this, the gripping element 10 is provided with a collar 13, while the fastening element 20 is equipped with a support element 23. Collar 13 and support element 23 form the head region 25 of the handle 100. Situated between support element 23 and collar 13 is a telescopic damping element 30, the construction of which from at least one piston and one cylinder is not illustrated more specifically.

Finally, Fig. 4 schematically shows an arrangement in which the gripping element 10 is of a construction telescope-like in itself. For this purpose, a first sub-element 17 of the gripping element 10 is designed as a piston 32 at its end facing away from the fastening element 20, while a second sub-element 18 is formed as a cylinder 34 at its end facing the fastening element 20. The piston 32 is mounted in a manner displaceable in the axial direction in the cydnder 34 and in a damping manner, so that the two sub-elements 17, 18of the gripping element 10 are guided telescopic-like one inside the other. It is likewise possible to subdivide the gripping element 10 into more than two sub-elements, the sub-elements each being mounted, as pistons and cylinders, in a displaceable manner one inside the other (not illustrated) Fig. 5 illustrates a further embodiment of a handle according to the invention having a telescopic damping element 30. In this case, the telescope-like damping element 30 is arranged on the handle 100 in such a way that, after attachment of the handle 100 to a housing 40 of a hand-held power tool, the telescopic damping element 30 is arranged in the housing 40. The housing 40 is only partially illustrated, for simplification. The telescopic damping element 30 is connected to the fastening element 20, so that the telescopic damping element 30 forms part of the handle 100. The piston 32 of the telescope-like damping element 30 is mounted, at one end, displaceably in the cylinder 34 and, at the other end, fixedly in the gripping element 10. The cylinder 34 is filled in particular with a gaseous damping means 35. The cylinder 34 is situated in turn in a receptacle 26, which is provided with an external thread. As a result, the receptacle 26 of the telescopic damping element 30 can be screwed into a receptacle 42 of the housing 40, which receptacle is provided with an internal thread. In this case, the telescopic damping element 30 is axially arranged. In addition, the cylinder 34 is mounted in a vibration-damping manner in the radial direction by a damping element 50 in the form of an 0-ring made of elastic material, e.g. an elastomer. After mounting the handle 100 on the housing 40, the receptacle 26, the cylinder 34 and the piston 32 of the damping element 30 projects into the housing 40.

Claims

Claims 1. Handle comprising a gripping element (10) and a fastening

element (20), and also at least one damping element (30), characterised in that the damping element is a telescope-like damping element (30)
2. Handle according to Claim 1, characterised in that the telescopic damping element (30) comprises at least one cylinder (34) and a piston (32) displaceably mounted in the cylinder (34)
3. Handle according to Claim 2, characterised in that the telescopic damping element (30) comprises a plurality of cylinders (34) connected in series, each two successive cylinders (34) being connected by a displaceably mounted piston (32).
4. Handle according to one of Claims 2 and 3, characterised in that the piston (32) is mounted in the cylinder (34) in a damping manner by means of a damping means (35)
5. Handle according to Claim 4, characterised in that the damping means (35) is an elastic element, in particular an elastorner, foam or the like.
6. Handle according to Claim 4, characterised in that the damping means (35) is a gas cushion or a liquid cushion.
7. Handle according to one of the preceding claims, characterised in that the telescope-like damping element (30) is axially arranged.
8. Handle according to Claim 7, characterised in that the telescopic damping element (30) is mounted in a vibration-damping manner in the radial direction by means of a second damping element (50)
9. Handle according to one of the preceding claims, characterised in that the telescope-like damping element (30) is radially arranged.
10. Handle according to one of the preceding claims, characterised in that the fastening element (20) is mounted in a vibration-damping manner with respect to the gripping element (10) by means of the telescope-like damping element (30)
11. Handle according to one of the preceding claims, characterised in that. after attachment of the handle to a housing (40) of a hand-held power tool, the telescopic damping element (30) is arranged in the housing (40).
12. A handle substantially as herein described with reference to the accompanying drawings.
13. Hand-held power tool comprising a handle according to one of the preceding claims.