GB2409832A

GB2409832A - Portable electric machine tool

Info

Publication number: GB2409832A
Application number: GB0500345A
Authority: GB
Inventors: David Jenni; Remo Frei; Curdegn Bandli
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2004-01-10
Filing date: 2005-01-07
Publication date: 2005-07-13
Anticipated expiration: 2025-01-07
Also published as: GB0500345D0; DE102004001551A1; CN1636682A; GB2409832B

Abstract

A portable electric machine tool 10 has at least one battery-powered electric motor (11, Fig.2) which can be placed on the back of a user 52 by means of a carrying unit 50. The electric motor is used to drive a tool 40 via a flexible shaft 30. The electric motor and at least one battery 21, 22 suitable for it are combined in a driving unit 20, which can be exchangeably received in the carrying unit 50. The at least one battery 21, 22 may be detachably connected to the driving unit 20, and may be arranged for parallel or sequential discharging during operation of the tool 40. The tool 40 may be a screwdriver, hammer, grinder, sander, drill, saw or the like, and the carrying unit 50 may include an adjustable and/or padded hip belt 53 and/or straps 58,60. External electrical sockets (27,28, fig.2) may also be provided.

Description

Portable electric machine tool

Prior art

The invention starts from a portable electric machine tool of the generic type defined in the precharacterising clause of Claim 1.

In a known portable electric machine tool of this type (DE 299 03 963 U1), there is provided a frame which is to be carried on the back of the user and is held on the body of the user by means of carrying straps, it being intended for the frame to bear against the user's back. Provided in the frame on the one hand is the electric driving motor and furthermore, dissociated therefrom, a battery pack. In addition, the frame contains a control device for controlling the electric motor, the power consumption, etc. The electric motor is situated right at the bottom in the frame. Leading off laterally from it is the electrical shaft, to the free end of which is attached a driven tool in the form of a hedge trimmer. In this case, the flexible shaft is guided laterally and beneath the arms of the user forwards. This is a great hindrance and gets in the way during use. Also disadvantageous is the frame which can be carried on the back, it being large, heavy and unwieldy in this design.

Advantages of the invention The portable electric machine tool according to the invention, with the features of Claim 1, has, in contrast, the advantage of a low-cost, compact and space-saving construction, in which the driving unit can be of small design and can be optimally carried above the hip on the back of the user.

Advantageous developments and improvements of the portable electric machine tool specified in Claim 1 are possible by the measures presented in the further claims.

It may be advantageous here for the carrying unit to have a hip belt and on the latter, on the side associated with the back of the user, a receptacle situated above the hip of the user and, for example, in the form of detachable loops, straps or the like, fixable by means of touchand-close fasteners, for exchangeable mounting of the driving unit.

It may furthermore be advantageous in this case for the carrying unit to have two shoulder straps, which lead to the hip belt, are brought together on the region associated with the back of the user and are connected to a back strap leading to the hip belt. A further advantageous design is obtained when the hip belt, when viewed in the vertical direction, is approximately conically configured to match the hip contour of a user. It may be particularly advantageous for the hip belt to have, at least on one side, an approximately pocket-like push-in receptacle for a driven tool, which can be pushed into this push-in receptacle when not in use. It may furthermore be advantageous for the two shoulder straps to be connected to one another, on the side associated with the chest of the user, by means of a transverse chest strap. The hip belt and/or the shoulder straps and/or the back strap and/or the chest strap may be padded and/or adjustable.

It may furthermore be advantageous for the carrying unit to have guide means which act on the flexible shaft in such a way that the flexible shaft is secured against slipping off in the shoulder region, starting from the back region of the user. These guide means can act on the flexible shaft in such a way that the latter is guided over the back and one of the two shoulders of the user and from there straight or approximately diagonally over the chest of the user forwards. It may furthermore be advantageous for at least one of the shoulder straps, or both, to have in the shoulder region a guide extending along it, in particular a loop channel receiving the flexible shaft. In addition, the back strap may advantageously have a guide extending along it, in particular a loop, or loop channel, receiving the flexible shaft. It may furthermore be advantageous for the guide means, in particular the guides, to be detachably fixable to the carrying unit, for example designed in the form of separate loops or the like and detachably fixable to the carrying unit for example by means of touch-and close fasteners or the like. Instead, these guide means may also comprise bands, strips or the like, which are held on the carrying unit on the one hand and can be opened and closed on the other hand, in order to receive the flexible shaft therein, the closed state being ensured for example by means of detachable touch-and-close fasteners.

Drawings The invention is explained in more detail with the aid of an exemplary embodiment illustrated in the drawings, in which: Fig. 1 shows a schematic perspective view of a portable electric machine tool held by means of a carrying unit, Fig. 2 shows a schematic perspective view of the driving unit of the portable machine tool in Fig. 1, Fig. 3 shows a schematic perspective view of a driven tool of the portable machine tool in Fig. 1, Fig. 4 + 5 each show a schematic perspective and more detailed view of the carrying unit in Fig. 1, seen from the rear in Fig. 4 and from the front in Fig. 5.

Description of the exemplary embodiment

The drawings schematically illustrate a portable electric machine tool 10 having a driving unit 20, a flexible shaft and almost any desired driven tool 40, which can be connected in a rotationally drivable manner to one end of the flexible shaft 30 and may consist, for example, of a screwdriver, hammer, saw, grinder or sander, drill, hedge trimmer or the like. In the exemplary embodiment shown, a screwdriver, for example, is provided as the driven tool 40, the screwdriver being connected to the flexible shaft 30 in the illustration in Fig. 1. The driving unit 20 contains an electric motor 11, not visible in more detail, which, depending on the design, has gearing connected downstream and which can be powered by at least one battery suitable for it, in the exemplary embodiment shown by two batteries 21, 22 which are rechargeable. The electric motor, not visible, and at least one battery 21, 22 suitable for it are combined in the driving unit 20 to form a utility unit, to which the flexible shaft 30 is connected by the other end opposite the driven tool 40. The portable machine tool 10 can be securely placed on the schematically indicated back 51 of a user 52 by means of a schematically indicated carrying unit 50.

In the exemplary embodiment shown, the driving unit 20 has two batteries 21, 22, which are detachably connected to the driving unit 20 and are designed as conventional exchangeable batteries. In a modified exemplary embodiment, only one battery may be provided instead, or more than two batteries are present. The electric motor, not illustrated in more detail, is situated inside a housing 23 of the driving unit 20, to which housing the batteries 21 and 22 are attached exchangeably on respective sides. The driving unit 20 further contains, inside the housing 23, at least one control device 24 integrated into this unit, indicated merely by dashed lines in Fig. 2. The control device 24 serves to control, for example, the electric motor of the driving unit 20 and the power consumption. The driving unit 20 has a schematically indicated exchangeable receptacle 25, 26 for each battery 21, 22. The at least two batteries 21, 22 are arranged and/or controlled inside the driving unit 20 in such a way that parallel or sequential discharging of the batteries 21, 22 is possible when the driven tool 40 is switched on.

The portable machine tool 10 further has at least one additional electrical connection, to which a further, external electrical consumer can be connected. In the exemplary embodiment shown, two such additional electrical connections 27 and 28 are indicated, these being arranged on the driving unit 20. These connections 27 and 28 each comprise, for example, a socket, in the form of a cigarette lighter socket for example. In another exemplary embodiment, not shown, the at least one additional connection 27, 28 is arranged instead on the carrying unit 50, and preferably in the front region thereof, and is connected to the driving unit 20 by a connection cable running from the front of the carrying unit 50 to the rear thereof, where the driving unit 20 is exchangeably received in the carrying unit 50.

The electric motor, not shown specifically, contained in the driving unit 20 is received therein in a manner accessible for maintenance. To this end, it may be advantageous for the driving unit 20 to have, for example, a removable, merely schematically indicated cover 29 for servicing purposes or the like.

The flexible shaft 30 can be detachably coupled, by means of a merely schematically indicated quick-connect coupling 31 at one end and 32 at the other end, to the driving unit 20 and a driven tool 40, respectively. The driven tool 40 has a switch 41 for switching on and switching off the drive taking place via the flexible shaft 30. The switch is connected to an in particular electrical control line 33, leading from the driving unit 20, in particular from the control device 24 thereof. The flexible shaft 30 may be combined with at least one such control line 33. It is particularly advantageous for the at least one control line 33 to be integrated into the flexible shaft 30 and for the connections thereof to be integrated into the quick- connect couplings 31, 32 of the flexible shaft 30. Such an electrical control line inside the flexible shaft 30 is merely indicated in Figs. 2 and 3.

The carrying unit 50 has a circumferentially adjustable and padded hip belt 53. On the side associated with the back 51 of the user 52, the hip belt 53 is provided with a receptacle, generally denoted by 54, which is situated above the hip of the user 51 and serves for exchangeable mounting of the driving unit 20. In the exemplary embodiment shown, the receptacle 54 advantageously comprises, for example, detachable loops 55 and 56 fixable by means of touch-and-close fasteners, which loops may be guided, for example, in an associated groove 15, 16 of the driving unit 20, while extending over the driving unit 20 on the outside in the region of the groove 15 and 16, respectively, and securing it to the rear of the hip belt 53.

The carrying unit 50 further has two shoulder straps 57 and 58, which lead to the hip belt 53 and may likewise be padded and adjustable. The shoulder straps 57, 58 are brought together, on the rear region associated with the back 51 of the user 52, approximately in the shoulder region 59 and connected there to a back strap 60 leading to the hip belt 53. When viewed in the vertical direction, the hip belt 53 is approximately conically configured to match the hip contour of a user 52, and thus anatomically adapted. The back strap 60 may likewise be padded and adjustable. The two shoulder straps 57, 58 may be connected to one another, on the side associated with the chest of the user 52, by means of a transverse chest strap 61, which may likewise be padded and adjustable. As can be seen from Figs. 1 and 4, the hip belt 53 has, at least on one side, an approximately pocket-like push-in receptacle 62 for a driven tool 40. The carrying unit 50 thus designed has a certain similarity to a rucksack and can be optimally adjusted to different body sizes and body shapes by individually adjusting the belt or straps, in particular the hip belt 53, shoulder straps 57, 58, back strap 60 and chest strap 61. The design of the hip belt 53 and its rear receptacle 54 for the driving unit 20 ensures that the latter sits above the hip of the user 52 and thus anatomically correctly, without causing particular additional loads on the body.

A further special feature of the carrying unit 50 is that it has guide means, indicated schematically by 63, 64 and 65, which act on the flexible shaft 30 in such a way that the latter is secured against slipping off, starting from the back region of the user 52, at least in the shoulder region of the user. These guide means 63 to 65 act on the flexible shaft 30 in such a way that the latter is led over the back 51 and - as chosen by the user 52 - over one of the two shoulders and from there straight or diagonally over the chest of the user 52 forwards. Each shoulder strap 57, 58 has, as guide means 64, 65 in the shoulder region, a guide extending along it and in the form, in particular, of a loop channel, through which the flexible shaft 30 is guided. This guidance of the flexible shaft 30 ensures that the latter is guided, starting from the driving unit 20, approximately vertically upwards over the back 51 and over the shoulder of the user 52 forwards and downwards, while preventing the flexible shaft 30 from slipping off the shoulder for instance. In the rear region of the carrying unit 50, the back strap 60 there has, as guide means 63, a guide extending along the back strap 60 and in particular in the form of a loop, or loop channel, receiving the flexible shaft 30. This ensures that the flexible shaft 30 is guided, in the region of the back 51 of the user 52, securely upwards to the shoulder and cannot deviate laterally. The guide means 63 to 65 described can be detachably fixed to the carrying unit 50, for example by means of touch-and-close fasteners in the manner of Velcro (my) fasteners or the like. Instead, these guide means 63 to 65 may also comprise parts which are opened and closed, being held in the closed position by means of touch-and-close fasteners. Owing to the described guidance and holding of the flexible shaft 30 on the carrying unit 50, the flexible shaft 30 does not get in the way of the user 52 when the driven tool 40 is not in use and, as shown in Fig. 1, has been stored away by pushing into the push-in receptacle 62 of the hip belt 53. With regard to guidance of the flexible shaft 30 over one of the shoulders, the user 52 has the choice whether the guidance takes place over the left shoulder and if so with the use of the guide means 65 there or over the right shoulder and if so with the use of the guide means 64 there. This guidance of the flexible shaft 30 enables ergonomic working by means of respectively attached driven tools 40, which are driven, via the shaft 30, by the driving unit 20 placed on the back of the user 52. As a result of the fact that the portable machine tool 10 is divided up into a driving unit 20 and a driven tool 40 which are connected by the flexible shaft 30, various advantages result. The external placement of the power supply and enlargement of its capacity makes the tool part formed by the driven tool 40 significantly lighter, more compact and handier. Owing to the special design, the driving unit 20 is small, light and easily exchangeable.

This unit can be optimally carried above the hip on the back of the user 52. The at least one additional external connection 27, 28 allows other external consumers to be operated as well.

Claims

R.307461 ROBERT BOSCH GMBH, 70442 Stuttgart Claims 1. Portable electric

machine tool, with at least one battery-powered electric motor (11) which can be placed on the back (51) of a user (52) by means of a carrying unit (50) and used to drive a driven tool (40), such as a screwdriver, hammer, grinder or sander, drill, saw or the like, via a flexible shaft (30), characterized in that the electric motor (11) and at least one battery (21, 22) suitable for it are combined in a driving unit (20) which can be carried on the back and exchangeably received in the carrying unit (50).
2. Portable electric machine tool according to Claim 1, characterized in that the driving unit (20) has two or more batteries (21, 22), which are combined with the electric motor.
3. Portable electric machine tool according to Claim 1 or 2, characterized in that the at least one battery (21, 22) iS detachably connected to the driving unit (20) and designed as an exchangeable battery.
4. Portable electric machine tool according to one of Claims 1 to 3, characterized in that the driving unit (20) contains a control device (24) integrated into it, for controlling in particular the electric motor, the power consumption or the like.
5. Portable electric machine tool according to one of Claims 1 to 4, characterized in that the driving unit (20) has an exchangeable receptacle (25, 26) for each battery (21, 22).
6. Portable electric machine tool according to one of Claims 1 to 5, characterized in that the at least two batteries (21, 22) are arranged and/or controlled in the driving unit (20) in such a way that parallel or sequential discharging takes place during operation of a connected driven tool (40).
7. Portable electric machine tool according to one of Claims 1 to 6, characterized by at least one additional electrical connection (27, 28), in particular a socket, to which a further electrical consumer can be connected.
8. Portable electric machine tool according to Claim 7, characterized in that the at least one additional connection (27, 28) is arranged on the driving unit (20).
9. Portable electric machine tool according to Claim 7, characterized in that the at least one additional connection (27, 28) is arranged is on the carrying unit (50), preferably in the front region thereof, and connected to the driving unit (20) by a connection cable.
10. Portable electric machine tool according to one of Claims 1 to 9, characterized in that the electric motor is contained in the driving unit (20) in a manner accessible for maintenance, in particular has a cover (29) removable for servicing purposes.
11. Portable electric machine tool according to one of Claims 1 to 10, characterized in that the flexible shaft (30) can be detachably coupled to the driving unit (20) and/or a driven tool (40) by means of a quickconnect coupling (31, 32).
12. Portable electric machine tool according to one of Claims 1 to 11, characterized in that the flexible shaft (30) is combined with at least one control line (33) connecting a connected driven tool (40) to the driving unit (20).
13. Portable electric machine tool according to Claim 12, characterized in that the at least one control line (33) is integrated into the flexible shaft (30) and the connections thereof are likewise integrated into the quick-connect couplings (31, 32) of the flexible shaft (30).
14. A portable electric machine tool substantially as herein described with reference to the accompanying drawings.