DE8907240U1 - Carbon brush holder - Google Patents

Description

SCHUNK

Metal and Plastics GmbH Main Street 97

6301 Wettenberg

Description Carbon brush holder

The innovation relates to a carbon brush holder with a holder body, which comprises a guide for receiving the carbon brush, as well as a pocket-shaped holder for locking a removable roller band spring carrier, whereby the roller band spring acts on the carbon brush.

The corresponding carbon brush holders are designed for electrical machines, whereby the roller band spring ensures that the carbon brush is constantly in contact with a commutator or a slip ring. In order to prevent the motor from coming to a standstill or being damaged, the wear of the carbon brushes must be monitored.

In order to avoid time-consuming intermediate checks to ensure that the carbon brushes need to be changed in good time, it is known to arrange a signal generator in the form of a switching element in carbon brush holders where a pre-tensioned pressure lever acts on the carbon brush in order to receive a signal when a certain level of wear is reached. Appropriate measures can be found, for example, in German utility model 87 14 263.

12. 6.1989/291 55/pr/bn ^: '.'.'' ^: .. ^: i

STREET & FABRIC REQS Patent Office·!· ■ European Patent Attorney»

The purpose of this innovation is to design a carbon brush holder with a roller band spring of the type described above in such a way that a certain level of wear on the carbon brush is automatically detected. It should also be possible to subsequently equip existing brush holders with the appropriate means.

According to the innovation, the task is essentially solved by the fact that the carrier has a switching element on which an actuating element interacting with the roller band spring acts depending on a certain wear of the carbon brush.

--. According to the innovation, the replaceable part of the brush holder, namely the carrier holding the roller band spring, is provided with a switching element, preferably a microswitch, on which an actuating element, preferably in the form of a leaf spring, acts when the roller band spring is rolled up to a circumference .

·..; which corresponds to the wear of the carbon brush to a just ii?; permissible extent. With other hoards, the roller band spring state is used directly to derive a signal for the wear of the carbon brush.

_{f &lgr;} In a further proposed solution, it is provided that the v' carrier, which in a known manner has a substantially U- or V-shape, has fastening elements such as sheet metal pieces on both sides in the root area of the leg facing the roller band spring in order to fasten the roller band spring on the side of this leg facing the carbon brush and the leaf spring on the opposite side.

The leaf spring, i.e. the actuating spring, preferably has an L-shaped geometry, with an arcuate bulge extending in the direction _of the roller band spring passing through an opening provided in the leg in order to interact with the roller band spring. If the roller band spring is extended to a great extent, the interaction with the arcuate bulge of the actuating spring causes its free end not to rest on the

STREET & FABRIC REQS Patent Attorney - European Patent Attorneys

the actuating element, such as a plunger of a microswitch. The more the roller band spring is rolled up, the further the section of the roller band spring extending from the leg moves away from it, so that the curved section can be moved further in the direction of the carbon brush. This in turn means that the free end of the actuating spring is pivoted in such a way that the switching element is activated and thus an indication is given regarding the reaching of a certain level of wear of the carbon brush.

The wear of a carbon brush can therefore be monitored using simple structural measures, whereby no changes need to be made to the brush holder itself. Rather, all that is required is an addition to the carrier holding the roller band spring, whereby the existing carriers only need to be provided with a microswitch and an opening for the leaf or actuating spring in order to enable interaction with the roller band spring.

Further details, advantages and features of the innovation arise not only from the claims, the features to be taken from them - individually and/or in combination - but also from the detailed description of a preferred embodiment to be taken from the drawing.

Show it:

Fig. 1 a sectional view of a brush holder with
unused carbon brush and

Fig. 2 the brush holder according to Figure 1 with partially
worn carbon brush.

The figures show a brush holder which comprises a holder body (1) with a guide (2) for a carbon brush (3) and a pocket-shaped holder (20) for a carrier (18) which in turn holds a roller band spring (5) acting on the carbon brush (3). The

12.6.1989/29155/pr /for .'.'·' ^: .. ^: :

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In the exemplary embodiment, the carrier (18) has a U-shaped form with a leg (23) facing the roller band spring (5) and forming a lateral guide via sections (22). In the tumbler area of the leg (23), sheet metal pieces (6) and (7) are arranged via fastening elements such as rivets (4), with the roller band spring (5) being fixed between the sheet metal piece (6) and the leg (23) and a leaf spring serving as an actuating spring (8) being fixed between the sheet metal piece (7) and the opposite surface of the leg (23), which interacts with a switching element such as a microswitch (9) in the manner described below when the carbon brush is worn to a degree that is to be detected (Fig. 2). The microswitch (9) is attached to the leg (25) of the carrier (18) that rests against the outer wall (24) of the holder (20) via a screw element (10). A cable (11) extends from the microswitch (9) and is attached via a strain relief clamp (13) using rivets.

(14) is fixed to the end area of the leg (25). In this area, the cable is surrounded by a shrink tube (12).

The actuating spring (8) essentially has an L-shaped form with a free leg section (15) which runs underneath an actuator (16) such as the plunger of the microswitch (9). The section extending from the fastening, i.e. between the sheet metal piece (7) and the leg (23), has a roughly S-shaped form, with an arcuate bulge (26) passing through an opening (17) in the leg (23) in order to interact with the roller band spring (5), i.e. to be able to rest against it.

When the roller band spring (5) is extended, the section (21) of the roller band spring (5) extending from the fastening runs closer along the leg (23) of the carrier (18) than when it is rolled up, i.e. when the carbon brush (19) is worn. The latter means that the curved bulge (26) in the drawing moves further to the left, so that as a result the leg

(15) is moved upwards to act on the actuator (16) and activate the microswitch (9). This

22.8.1989/29155/bn

STREET & FABRIC REQENi .!,',,' ' Patent Attorney« - European Patent Attorney»

a signaling circuit is closed, via which appropriate signals are communicated that the carbon brush (19) is worn to such an extent that it must be replaced in order to ensure that damage to a commutator or a slip ring is avoided due to the carbon brush (19) slipping out of the guide (2) in an uncontrolled manner.

12.6.1989/29155/pr/fen

Claims (1)

STREET & FABRIC RAIN PalentanvrtHte - European Patent Attorney» &bull;&igr; in a·· t &bull; ·( to it> SCHUNK Metal and Plastics GmbH Main Street 97 Wettenberg Protection claims Carbon brush holder 1. Carbon brush holder with a holder body which comprises a guide for receiving the carbon brush and a receptacle for the replaceable fixing of a carrier of a roller band spring which acts on the carbon brush,
characterized, that the carrier (18) has a switching element (9) on which an actuating element (8) interacting with the roller band spring (5) acts depending on a certain wear of the carbon brush (3, 19). 2. Carbon brush holder according to claim 1,
characterized, that the actuating member (8) is a leaf spring which partially rests against the roller band spring (5), the free end of which acts on the switching element (9). 3. Carbon brush holder according to at least one of the preceding claims, characterized, that the carrier (18) has a substantially U- or V-shape and in the root area of one of the roller band springs (5) 12.6.1988/29155/pr/i>ri '.'.''''..'' \ &bull;&igr; · · STREET & STOH-KEGEN .' · · ■'. « ·..· ""· facing leg (23) has fastening elements such as sheet metal pieces for the roller band spring (5) and the actuating element (8). 4. Carbon brush holder according to claim 3,
characterized, that the roller band spring (5) is fastened on the side of the leg (23) of the carrier (18) facing the carbon brush (3, 19) and the leaf spring (8) is fastened on the opposite side. 5. Carbon brush holder according to at least one of the preceding claims, characterized,
that the leaf spring (8) has a substantially L-like geometry with an arcuate section (26) passing through an opening (17) in the leg (23) and interacting with the roller band spring (5). 6. Carbon brush holder according to at least claim 5,
characterized, that the leg of the leaf spring (8) having the arcuate bulge (26) has approximately an S-shape. 7. Carbon brush holder according to at least claim 1,
characterized, that the switching element (9) is detachably connected to the carrier (18) and is preferably a microswitch. 12.6.1988/29155/pr/bii