EP0878037A1 - Brush-holder with wear detection device - Google Patents
Brush-holder with wear detection deviceInfo
- Publication number
- EP0878037A1 EP0878037A1 EP96934695A EP96934695A EP0878037A1 EP 0878037 A1 EP0878037 A1 EP 0878037A1 EP 96934695 A EP96934695 A EP 96934695A EP 96934695 A EP96934695 A EP 96934695A EP 0878037 A1 EP0878037 A1 EP 0878037A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- brush
- holder
- pressure finger
- oscillating
- insulating support
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
- H01R39/00—Rotary current collectors, distributors or interrupters
- H01R39/02—Details for dynamo electric machines
- H01R39/58—Means structurally associated with the current collector for indicating condition thereof, e.g. for indicating brush wear
Definitions
- the supplying of electric power to most electric motors is performed by means of so-called “brushes”, i.e. conducting bars, usually made of graphite, the free end of which is kept in contact with the surface of the commutator, which rotates integrally with the rotor of the motor itself.
- the brush is mounted freely sliding inside a fixed guide, called a “brush-holder”, and is pressed against the commutator by respective pressure-spring means; these means are able to follow the sliding movement of the brush inside the brush-holder as the wear occurs, said wear occurring relatively rapidly precisely on account of the functional characteristics of the brush.
- the brush-holder has associated with it an insulated contact pin connected to one of the electric poles of a signalling circuit; when the pressure finger reaches its end-of-travel position, its body comes directly into contact with the pin, which is therefore in turn crossed by the electric current and supplies power to the electric signalling circuit, activating it.
- This arrangement which is certainly simpler and less costly, nevertheless has various drawbacks:
- the oscillating pressure finger and the pressure spring have the same electric potential as the brush-holder body; therefore, during normal operation, the flowing of current across the spring may easily occur. This produces - particularly in the case of the already mentioned high-power motors which are subject to severe working conditions - overheating of the spring, with an annealing effect and hence loss of its resilient function.
- the aforementioned insulated contact pin is located in close proximity to the brush-holder body; even if it is isolated from the latter, it very frequently happens that the graphite powder produced as a result of wear of the brush is deposited on the insulation and forms a bridge between the brush-holder body and said pin, thus causing continuous powering of the signalling circuit.
- the object of the present invention is therefore that of proposing a device for signalling the wear of brushes of the general type described above, which has a simple and economical design and ensures moreover safe operation without any of the drawbacks mentioned. This object is achieved by means of the characteristic features mentioned in Claim 1.
- Figs. 1 a and 1 b show a front view of the brush-holder according to the invention, with the oscillating pressure finger in the start-of-travel and end-of-travel positions, respectively;
- Figs. 2 and 3 show, respectively, a side view and plan view of the same brush-holder.
- the brush-holder comprises a main body 1 provided with a bracket 1 a for attaching an electric cable (not shown) for connection of the brush 2.
- the body 1 has a tubular cross- section in the form of a parallelogram so as to constitute a guide 1 b for a brush 2 in the form of a bar with a rectangular cross-section (see also Fig. 3).
- the main body 1 extends moreover into a lug 3 in the form of a plate, provided with eyelet holes 1 c for receiving screws or bolts (not shown) for fixing onto the flat surface of the fixed part (not shown) of the motor; the plate 3 also has engaging in it a bolt 4 for fixing the main power supply cable (also not shown).
- a double right-angled support 5 which, according to a fundamental characteristic feature of the present invention, is made of electric insulating material.
- the support 5 has in fact, seen in plan view, a substantial U-shaped section, the base 5a of which is used for fixing to the side of the body 1 and the two arms 5b and 5c are used mainly for supporting the pressure finger 6.
- the support 5 is made preferably of plastic material, for example thermoplastic material, if necessary reinforced with glass fibre and/or mineral fillers, or thermosetting material, also reinforced.
- the support 5 may also be made of metal, although completely lined with a layer of insulating material.
- the pressure finger 6 made of metal, is mounted oscillating about a pin 7 which is mounted with its ends housed in saddle-shaped recesses formed in the upper edge of the arms 5b and 5c (see Figures 1 a and 1 b).
- a central eyelet 6a of the pressure finger 6 has fastened to it one of the ends of a tension spring 8, the other end of which is fastened to a cross-member 9, described in more detail below.
- the end 6b of the pressure finger 6 is covered by an insulating cap 10, via which it rests on the upper surface of the brush 2; alternatively, the pressure finger may also be mainly lined with a layer of insulating plastic material. Obviously it is also possible for the pressure finger 6 to be made completely of metal when, as in the case of some known arrangements, the upper surface of the brush 2 has fixed to it an insulating support head (not shown, for example of the type known by the trade name FLEXTOP).
- the pressure finger 6 is designed to oscillate between a start-of- travel position (shown in continuous lines in Figure 1 a), where its free end 6b-10 is resting on the top of a new brush 2, and an end-of-travel position (shown in continuous lines in Figure 1 b) where the end 6a-10 is resting on a brush which is almost totally worn.
- the cross-member 9 ends in a terminal 9a (Fig. 2) for the electrical connection to the signalling circuit; the terminal 9a projects preferably from the end close to the plate-shaped lug 3.
- a single long bar 9 is mounted on several parallel supports 5 and also has a single terminal 9a in the position shown.
- the brush-holder according to the invention also incorporates a metal contact strip 1 1 which, according to another important characteristic feature of the invention, is of a resilient nature and has a top end which is substantially arched, as shown, for the purpose explained in more detail below.
- This strip 1 1 is fixed against the wall of the body 1 , between the latter and the base 5a of the U-shaped support 5, and therefore has the same electric potential as the body 1 .
- the brush 2 is supplied principally with the current conveyed by a flexible conductor (not shown) fixed to the connecting bracket 1 a and partially also via the metal walls of the guide 1 b formed in the body 1 .
- the oscillating pressure finger 6 is perfectly isolated from these conducting metal parts thanks, on the one hand, to the insulating cap 10 and, on the other hand, to the mounting of the pin 7 on the arms 5b, 5c of the insulating support 5.
- the spring 8 is equally well insulated, being fixed to the insulated pressure finger 6 and to the cross-member 9 which is in turn mounted on the insulating support 5.
Abstract
Description
Claims
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
ITMI952139 | 1995-10-18 | ||
IT95MI002139A IT1277267B1 (en) | 1995-10-18 | 1995-10-18 | BRUSH HOLDER WITH WEAR DETECTION DEVICE |
PCT/EP1996/004483 WO1997015099A1 (en) | 1995-10-18 | 1996-10-15 | Brush-holder with wear detection device |
Publications (1)
Publication Number | Publication Date |
---|---|
EP0878037A1 true EP0878037A1 (en) | 1998-11-18 |
Family
ID=11372383
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP96934695A Withdrawn EP0878037A1 (en) | 1995-10-18 | 1996-10-15 | Brush-holder with wear detection device |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP0878037A1 (en) |
IT (1) | IT1277267B1 (en) |
WO (1) | WO1997015099A1 (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7010959B2 (en) * | 2003-03-28 | 2006-03-14 | Schleifring Und Apparatebau Gmbh | Device and method for measuring mechanical path lengths by means of pneumatic pressure, in particular for sliding carbon contacts |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE8214872U1 (en) * | 1982-05-21 | 1982-10-14 | Heid & Co, GmbH, KG, Kohlebürsten- und Bürstenhalterfabrik, 6730 Neustadt | Carbon brush holder |
DE8316492U1 (en) * | 1983-06-06 | 1983-11-24 | Bohnenblust & Dietrich GmbH, 7893 Jestetten | Carbon brush holder |
DE8416981U1 (en) * | 1984-06-02 | 1985-12-12 | EMW Elektro-Motoren-Feinbauwerk Groschopp & Co GmbH, 4060 Viersen | Carbon brush holders for electrical commutator machines |
DE8600934U1 (en) * | 1986-01-16 | 1986-04-24 | Anton Piller GmbH & Co KG, 3360 Osterode | Brush holder for electrical machines with wear notification |
DE3920147A1 (en) * | 1989-06-20 | 1991-01-10 | Schunk Metall & Kunststoff | CARBON BRUSH HOLDER |
-
1995
- 1995-10-18 IT IT95MI002139A patent/IT1277267B1/en active IP Right Grant
-
1996
- 1996-10-15 EP EP96934695A patent/EP0878037A1/en not_active Withdrawn
- 1996-10-15 WO PCT/EP1996/004483 patent/WO1997015099A1/en not_active Application Discontinuation
Non-Patent Citations (1)
Title |
---|
See references of WO9715099A1 * |
Also Published As
Publication number | Publication date |
---|---|
IT1277267B1 (en) | 1997-11-05 |
ITMI952139A0 (en) | 1995-10-18 |
WO1997015099A1 (en) | 1997-04-24 |
ITMI952139A1 (en) | 1997-04-18 |
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Legal Events
Date | Code | Title | Description |
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PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
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17P | Request for examination filed |
Effective date: 19980506 |
|
AK | Designated contracting states |
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GRAG | Despatch of communication of intention to grant |
Free format text: ORIGINAL CODE: EPIDOS AGRA |
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17Q | First examination report despatched |
Effective date: 19981218 |
|
GRAG | Despatch of communication of intention to grant |
Free format text: ORIGINAL CODE: EPIDOS AGRA |
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GRAH | Despatch of communication of intention to grant a patent |
Free format text: ORIGINAL CODE: EPIDOS IGRA |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN |
|
18D | Application deemed to be withdrawn |
Effective date: 19990727 |