GB2461783A

GB2461783A - Rotationally adjustable power tool protective hood

Info

Publication number: GB2461783A
Application number: GB0910571A
Authority: GB
Inventors: Balazs Bogardi; Roland Kaplar
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2008-06-20
Filing date: 2009-06-18
Publication date: 2010-01-20
Anticipated expiration: 2029-06-18
Also published as: CN101607397B; RU2501640C2; RU2009123231A; DE102008002548B4; GB0910571D0; CN101607397A; DE102008002548A1; GB2461783B

Abstract

A power tool, in particular a hand-held angle grinder, has a protective hood 4 held on a bearing flange 3 of the power tool and is rotatable about the longitudinal axis 5 of the bearing flange between a number of latched positions, the hood 4 is additionally movable on the bearing flange 3 about a tilting axis 17 at right angles to the longitudinal axis 5 in order to move the hood 4 against a spring 7 between latched and unlatched positions. The hood 4 may have both longitudinal and radial play to allow the tilting movement and may be held between the bearing flange 3 and a fixing disc 6 rotationally secured to the bearing flange. A latching lug 15 may be formed on the hood 4, selectively engaging any one of a number of latching recesses 16 in the periphery of the fixing disc 6. The arrangement allows simple adjustment of the hood 4 without use of a separate actuating element such as a button. Spring 7 may be a wave-shaped spring ring.

Description

Description Title

Power tool, in particular hand-held power tool The invention relates to a power tool, in particular a hand-held power tool, such as, for example, an angle grinding machine, according to the precharacterising clause of Claim 1.

Prior art

EP 0 583 270 Si describes such an angle grinding machine which, for protection of the operator, is provided with a protective hood extending over the rotating tool and held on a clamping neck of the power tool. The protective hood can be moved into different angular positions, there being provided latching members which, at specific angular positions, secure the protective hood in the latching position on the clamping neck.

The protective hood has a slip-on collar which is slipped onto a clamping neck of the bearing flange and engages by way of radial projections in an annular groove in the clamping neck, whereby the protective hood can be rotated about the longitudinal axis of the bearing flange or clamping neck until the desired angular position is reached. A ring-like spring element which acts upon the protective hood with a force in the axial direction is held in a manner secure against rotation on the clamping neck.

The spring element carries latching members which slide into and out of corresponding latching elements of the protective hood, the protective hood being lockable by means of the locking members in their latching positions.

For rotation of the protective hood, the locking device has to be released with the aid of an actuating button, via which the latching members on the spring element are moved into the unlatching position. The adjustment of the protective hood can thus be carried out only if simultaneously the actuating button is acted upon and the protective hood is rotated.

Disclosure of the invention

The object on which the invention is based is to design a power tool equipped with a protective hood using simple constructional measures such that the protective hood can be moved into different angular positions with little adjusting effort, while at the same time secure latching in the angular positions is to be provided.

This object is achieved according to the invention by the features of Claim 1. The subclaims specify expedient developments.

The power tool according to the invention is preferably a hand-held power tool, in particular a hand-held grinding machine, such as, for example, an angle grinder. The power tool is provided with a protective hood which covers the tool and is held on a bearing flange of the power tool. The protective hood is held rotatably about the longitudinal axis of the bearing flange, in which the tool is rotatably mounted, a spring element which biases the protective hood into a latching position being supported on the bearing flange. The spring element ensures that the protective hood during normal operation of the power tool is in a secure latching position, in which undesired rotation of the protective hood about the bearing longitudinal axis, which is at the same time the axis of rotation of the tool, is precluded.

In addition to the rotating movement, the protective hood can perform a tilting movement, in which the protective hood is pivoted about a tilting axis running at right angles to the longitudinal axis of the bearing flange. This tilting axis is not a fixed axis, but enables tilting of the protective hood in each angular position which the protective hood can assume in relation to the bearing longitudinal axis or axis of rotation of the tool.

This embodiment has the advantage that the angular adjustment of the protective hood can be carried out with the least possible effort. To do this, all that is required is to pivot the protective hood against the force of the spring element about the tilting axis from a latching position into an unlatching position, then the protective hood can be rotated in the tilted state into a new angular position, in which the protective hood is held by the force of the spring element in a latching position again. The entire adjusting movement of the protective hood, composed of the tilting movement and the rotating movement about the bearing longitudinal axis, can be carried out by an operator without a tool and with only one hand by, for example, the operator grasping the protective hood at its radially outer edge, so that the protective hood can be tilted with minimal effort via the lever action between the outer edge and the axis of rotation and can be held in the tilted position for the purpose of rotating the protective hood.

Technically, the combination of the possibility of rotation about the bearing longitudinal axis and the tilting movement can be implemented in various ways. One possibility is, for example, a cardan joint which enables the rotation about the two intersecting or crossing axes, the tilting movement being possible in each angular position of the protective hood. According to a further configuration which can be embodied in a constructionally simple manner, the two movement possibilities of the protective hood are implemented by the latter being held on the bearing flange with axial and at the same time radial play. Owing to the biasing force of the spring element, the movement possibilities of the protective hood are constrained, while against the force of the spring element both the tilting movement and the rotating movement about the bearing longitudinal axis can be implemented. In this embodiment, no additional joint is required for the tilting movement or the rotational movement.

According to an advantageous embodiment, there is provided a fixing disc which is part of the connecting device via which the protective hood is held on the bearing flange.

The fixing disc is connected via connecting elements, for example screws, to the bearing flange and fixes the protective hood on the bearing flange. The fixing disc constitutes a means of captivating the protective hood, so as to ensure that the protective hood cannot fall off the bearing flange even in the case of an embodiment with axial play. Moreover, the fixing disc can perform additional tasks, in particular define the latching positions of the protective hood. For this, advantageously at least two latching members positioned in an angularly offset manner are arranged on the fixing disc, and are to be brought into a latching position with at least one latching member on the protective hood. The fixing disc is held in a rotationally fixed manner on the bearing flange, so that when setting the angular position only the protective hood is moved, while the angular position of the fixing disc is maintained.

The latching member on the protective hood is preferably embodied as a latching lug which is arranged adjacent to an aperture of the protective hood, by which the protective hood is placed on the bearing flange. The latching lug can extend at right angles to the wall plane of the protective hood, i.e. in the axial direction of the bearing flange.

Expediently, the protective hood has exactly one latching member, which cooperates with a plurality of latching members and is to be brought into a latching position, which latching members are preferably arranged on the fixing disc, each latching member on the fixing disc defining a latching position.

There may be arranged on the fixing disc, in addition to the latching members, supporting bodies which extend at right angles to the disc plane and on which the protective hood is supported. The supporting bodies prevent areal contact between the end face of the fixing disc and the wall of the protective hood, so that during the angular adjustment of the protective hood even lower frictional forces between the fixing disc and the protective hood are to be overcome.

The spring element, which biases the protective hood into the latching position, is preferably embodied as a spring ring, which in particular is of wave-shaped form. The spring ring can be placed on the clamping neck of the bearing flange, the wave shape, as a simple constructional embodiment of the spring ring, allowing an axial compression and an axial force, produced thereby, at any angular positions. Thus, the protective hood at a desired angular position can be tilted about the transverse axis extending at right angles to the longitudinal axis, an angular segment of the spring ring being axially compressed during this tilting movement, whereas the diagonally opposite angular segment of the spring ring is relieved.

The spring element and the fixing disc are preferably arranged on axially opposite sides of the protective hood, this constituting a possibility of securing the protective hood on the bearing flange which is simple to implement.

Further advantages and expedient embodiments can be found in the further claims, the description of the figures, and the drawings, in which: Fig. 1 shows a perspective view of a hand-held power tool embodied as an angle grinder, having a protective hood extending over the tool, Fig.2 shows an exploded view of a protective hood which is to be fastened to a bearing flange of a power tool, the fastening being effected with the aid of a fixing disc and a spring ring, Fig. 3 shows a perspective view of the protective hood mounted on the bearing flange, Fig. 4 shows the protective hood individually, Fig. 5 shows the fixing disc individually, Fig. 6 shows a plan view of the spring ring, Fig. 7 shows a side view of the spring ring.

In the figures, identical components are provided with the same reference symbols.

The hand-held power tool illustrated in Fig. 1 is an angle grinder 1, which accommodates in a housing 2 an electric drive motor for driving a tool which is rotationally mounted in a bearing flange 3. The bearing flange has the bearing longitudinal axis 5 which at the same time is the axis of rotation of the tool. A protective hood 4, which at least partly extends over the tool axially and radially and is to be locked in different angular positions, is additionally fastened to the bearing flange 3. When changing from one angular position to the next angular position, the protective hood 4 is rotated about the bearing longitudinal axis 5.

Fig. 2 shows an exploded view of the protective hood 4 for fastening to the bearing flange 3, including additional fastening components which are required for securing and holding the protective hood 4 on the bearing flange 3.

These fastening components are a fixing disc 6 which is screwed onto the bearing flange 3 via screws 8, and a spring element in the form of a spring ring 7.

As can be seen in Fig. 2 in conjunction with Fig. 3, the bearing flange 3 has a clamping neck 9, in which the bearing for rotatable mounting of the tool is accommodated.

The axial end face of the clamping neck 9 is provided with two diagonally opposite openings 11 which are aligned with openings 10 in the fixing disc 6, the screws 8 being passed through the openings 10 in the fixing disc and inserted or screwed into the openings 11 in the clamping neck 9.

Formed on the outer lateral surface of the clamping neck 9 is a radially widened supporting shoulder 12, on which the spring ring 7 is axially placed. The protective hood 4 has a slip-on collar 13 which encloses a central aperture and in the mounted state is slipped onto the clamping neck 9.

The axial side of the slip-on collar 13 facing away from the bearing flange 3 has a ring-shaped supporting surface 14, on which the fixing disc 6 is placed in the mounted state. The spring ring 7 and the fixing disc 6 are situated, in the mounted position, on different axial sides of the protective hood 4.

Immediately adjacent to the aperture enclosed by the supporting surface 14, a latching lug 15 is formed on the supporting surface integrally with the wall of the protective hood 4, the latching lug 15, which forms a latching member, extending perpendicularly to the plane of the wall of the protective hood. The latching lug 15 is to be brought into a latching position with assigned latching members on the fixing disc 6 which are embodied as latching recesses 16.

The central aperture enclosed by the supporting surface 14 in the protective hood 4 has expediently a greater diameter than the clamping neck 9 on the bearing flange 3, so that in the mounted state there is at least slight radial play between the clamping neck 9 and the slip-on collar 13 with supporting surface 14. Advantageously, there is also axial play in the axial direction in the mounted state according to Fig. 3, so that the protective hood 4 can move on the clamping neck 9 of the bearing flange 3. The axial play is, however, constrained by the force of the spring ring 7, since the spring element 7 acts upon the protective hood with an axial force and pushes the latter away from the bearing flange 3. Owing to the axial securing of the protective hood 4 by the screws 8 via the fixing disc 6, the protective hood is, however, captively held on the clamping neck, so that the spring force of the spring ring 7 cannot detach the protective hood 4 from the clamping neck 9. At the same time, the protective hood 4 can be axially pressed against the bearing flange 3 against the force of the spring element 7 according to the axial play.

In addition, the axial play in combination with the radial play enables a tilting movement of the protective hood 4, in which the protective hood is pivoted about a tilting axis 17 lying perpendicularly to the bearing longitudinal axis 5. The tilting axis 17 can extend, depending on the current angular position of the protective hood, in all angular directions perpendicularly to the bearing axis, so that accordingly a tilting of the protective hood 4 in all angular directions is also possible. The tilting axis 17 expediently intersects the bearing longitudinal axis 5, a crossing, i.e. a perpendicular course with spacing between the axes, optionally also being possible. The tilting axis 17 runs, in relation to the protective hood 4, with maximum spacing from the latching lug 15 and preferably centrally through the central aperture, by which the protective hood is slipped onto the clamping neck.

In order to change the angular position of the protective hood 4, the protective hood is firstly tilted about the tilting axis 17 in the direction of the bearing flange 3, to be precise in such a way that the latching lug 15 comes out of its latching position into an unlatching position with the latching recesses 16 in the fixing disc 6. The movement into the unlatching position is effected counter to the axially acting force of the spring ring 7. In the unlatching position, the protective hood 4 can be rotated by a desired angular amount about the bearing longitudinal axis 5, to be precise until the latching lug 15 on the protective hood 4 comes into engagement with a further latching recess 16 on the radial outer edge of the fixing disc 6. After that, the protective hood 4 is released, whereupon the protective hood is pushed into the latching position by the force of the spring element.

As can be seen from the individual illustration of the protective hood 4 according to Fig. 4, a single latching lug 15 rising perpendicularly above the wall plane of the protective hood is arranged in the region of the supporting surface 14. The latching lug 15 is situated on the supporting surface 14 on the side facing the extending-over edge 18 of the protective hood 4.

As can be seen from the individual illustration of the fixing disc 6 according to Fig. 5, a plurality of radially extending latching recesses 16 are made in the radial outer edge of the fixing disc 6 over an angular region of about 1800. Each latching recess 16 serves to receive the latching lug 15 on the protective hood 4, and thus each latching recess 16 constitutes exactly one latching position.

Furthermore, supporting bodies 19 rising axially above the end face of the fixing disc are formed on the fixing disc 6 integrally with the material of the fixing disc. A plurality of such supporting bodies 19 are provided in a manner distributed over the circumference. In the region of each latching recess 16 there is arranged one such supporting body 19 which, seen in the radial direction, inwardly delimits the latching recess 16. On the sides diagonally opposite the latching recesses 16 there are arranged two further supporting bodies 19 which each extend over a greater angular section in the circumferential direction.

As can be seen in Figures 6 and 7, the spring ring 7 is preferably of circular form. Seen in the axial direction (Fig. 7), the spring ring 7 has a wave shape, so that, seen as a whole, a three-dimensional course of the spring ring results. Owing to the wave shape in the axial direction, there is axial contact at different angular positions, on the one hand, with the supporting shoulder 12 on the bearing flange 3 and, on the other hand, on an end face of the supporting surface 14 on the protective hood 4.

Claims

Claims 1. Power tool, in particular hand-held power tool, for example hand-held grinding machine, having a protective hood (4) which covers a tool of the power tool, is held on a bearing flange (3) of the power tool and is rotatable about the longitudinal axis (5) of the bearing flange (3), a spring element (7) which biases the protective hood (4) into a latching position being arranged on the bearing flange (3), characterised in that the protective hood (4) is additionally movable on the bearing flange (3) about a tilting axis (17) at right angles to the longitudinal axis (5), whereby the protective hood (4) is to be moved between a latching position and an unlatching position via the tilting movement.
2. Power tool according to Claim 1, characterised in that the protective hood (4) is held on the bearing flange (3) with axial and radial play.
3. Power tool according to Claim 1 or 2, characterised in that there is provided a fixing disc (6) which is connected to the bearing flange (3) via connecting elements, the fixing disc (6) fixing the protective hood (4) on the bearing flange (3) H
4. Power tool according to Claim 3, characterised in that, when being moved between different latching positions, the protective hood (4) performs a rotating movement with respect to the bearing flange (3) and the fixing disc (6) held in a rotationally fixed manner on the bearing flange (3)
5. Power tool according to Claim 3 or 4, characterised in that a first latching member (15) is arranged on the protective hood (4) and at least two further latching members (16) positioned in an angularly offset manner are arranged on the fixing disc (6), it being the case that the latching member (15) on the protective hood (4) is to be brought into a latching position with each of the angularly offset latching members (16) on the fixing disc (6)
6. Power tool according to Claim 5, characterised in that the latching member on the protective hood (4) is in the form of a latching lug (15) which is arranged adjacent to an aperture in the protective hood (4), by which the protective hood (4) is to be placed on the bearing flange (3)
7. Power tool according to Claim 6, characterised in that the latching lug (15) on the protective hood (4) extends perpendicularly to the wall plane of the protective hood (4).
8. Power tool according to one of Claims 5 to 7, characterised in that exactly one latching member (15) is arranged on the protective hood (4)
9. Power tool according to one of Claims 3 to 8, characterised in that there are arranged on the fixing disc (6) supporting bodies (19) which extend at right angles to the disc plane and on which the protective hood (4) is supported.
10. Power tool according to one of Claims 3 to 9, characterised in that the spring element (7) and the fixing disc (6) are arranged on opposite sides of the protective hood (4).
11. Power tool according to one of Claims 1 to 10, characterised in that the spring element is in the form of a spring ring (7)
12. Power tool according to Claim 11, characterised in that the spring ring (7) is of wave-shaped form.
13. A power tool substantially as herein described with reference to the accompanying drawings.