US3898492A - Current interrupting brush holder assembly - Google Patents

Current interrupting brush holder assembly Download PDF

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Publication number
US3898492A
US3898492A US435323A US43532374A US3898492A US 3898492 A US3898492 A US 3898492A US 435323 A US435323 A US 435323A US 43532374 A US43532374 A US 43532374A US 3898492 A US3898492 A US 3898492A
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US
United States
Prior art keywords
brush
holder
commutator
contact
predetermined size
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.)
Expired - Lifetime
Application number
US435323A
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English (en)
Inventor
Louis J Vassos
William P Elzer
Alex F Gawron
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Skil Corp
Original Assignee
Skil Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Skil Corp filed Critical Skil Corp
Priority to US435323A priority Critical patent/US3898492A/en
Priority to CA214,843A priority patent/CA1019799A/en
Priority to AU76533/74A priority patent/AU7653374A/en
Priority to CH20875A priority patent/CH592968A5/xx
Priority to IT47614/75A priority patent/IT1032204B/it
Priority to DE19752502105 priority patent/DE2502105A1/de
Priority to FR7501629A priority patent/FR2258720B1/fr
Priority to JP50009198A priority patent/JPS50102804A/ja
Application granted granted Critical
Publication of US3898492A publication Critical patent/US3898492A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • 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

  • a trip member is released from a brush arm to open the electrical circuit.
  • a second embodiment causes the worn brushes to be discharged from the brush holder assembly, while a third embodiment employs a wedge contact which moves away from the worn brush to open the electrical circuit.
  • the present invention relates to commutator brush assemblies for electrical motors.
  • a standard brush assembly such as disclosed in the US. Pat. to Summerfield No. 3,108,201, when the brushes wear down to a selected size they are normally restrained by the brush holder assembly. This is to prevent the brushes from wearing completely away and allowing the spring and field wire to come in contact with the commutator. Should the spring or field wire touch the commutator, they can pit and gash it, requiring replacement of the motor.
  • a brush holder assembly includes brush means positioned within the holder for conducting current from a power source to the commutator of a motor and means for disconnecting the brush from the power source when it wears down to a predetermined size.
  • a trip member conducting current from the power source, is retained by a brush arm in electrical contact with the brush means. When the brush means wears down to the selected size, the trip member escapes from the brush arm thereby interrupting the current flow.
  • the brush means is positioned within the brush holder and urged against the commutator by a spring.
  • a contact member positioned between the spring and the brush means conducts current from the source to the brush. When the brush wears down to the predetermined size it is released from the holder assembly by the rotation of the commutator, the contact member being restrained by stops located in the holder.
  • a brush means is urged against the commutator by a spring. Positioned between the spring and the brush means is a wedge contact conducting current from the power source. When the brush means wears down to the predetermined size the wedge contact is urged by the spring into an auxiliary channel in the brush holder and out of electrical contact with the brush means.
  • FIG. 1 is a longitudinal section through a brush holder according to a first embodiment.
  • FIG. 2 is an end view of the brush holder of FIG. 1 having portions broken away.
  • FIG. 3 is a longitudinal cross-section similar to FIG. 1 showing the brush arm in operative position.
  • FIG. 4 is a cross-sectional view taken along the lines 44 of FIG. 3.
  • FIG. 5 is a longitudinal cross-section similar to FIG. 1 showing the trip member disengaged from the brush arm.
  • FIG. 6 is a perspective view of the trip member according to the first embodiment.
  • FIG. 7 is a longitudinal cross-section of a brush holder assembly according to a second embodiment showing the brush means in its initial position.
  • FIG. 8 is an end view of the brush holder of FIG. 7.
  • FIG. 9 is a longitudinal cross-section similar to FIG. 7 showing the brush means and Contact member just prior to interrupting current flow.
  • FIG. 10 is a cross-sectional view taken along the lines 10-10 in FIG. 9.
  • FIG. 11 is a partial cross-sectional view similar to FIG. 7 showing the brush being moved out of the holder assembly by the rotation of the commutator.
  • FIG. 12 is a perspective view of the contact member employed in the second embodiment.
  • FIG. 13 is a longitudinal cross-section of a brush holder assembly according to a third embodiment.
  • FIG. I4 is an end view of the brush holder of FIG. 13.
  • FIG. 15 is a cross-sectional view similar to FIG. 13 showing the wedge contact beginning to move out of contact with the brush.
  • FIG. 16 is a cross-sectional view taken along the lines 16-16 in FIG. 15.
  • FIG. I7 is a partial cross-sectional view similar to FIG. 13 showing the wedge contact just prior to interrupting current flow to the brush.
  • FIG. 18 is a crosssectional view similar to FIG. 13 showing the wedge contact completely out of the main channel of the brush holder.
  • FIG. 19 is a perspective view of the wedge contact according to the third embodiment.
  • a brush assembly 20 according to a first embodiment is shown.
  • a brush holder 22 preferably formed of a plastic material has a main channel 24 located therein.
  • a neck portion 26 separates the main channel 24 from an upper chamber 28.
  • a commutator brush 30 Positioned within the main chamber 24 is a commutator brush 30 adapted to contact a commutator 32 of an electric motor.
  • a current conducting brush arm 34 is press fitted to one end of brush 30.
  • a coil spring 36 urges the brush and arm into electrical contact with the commutator 32.
  • an L-shaped trip member 38 Mounted in the upper chamber 28 of brush holder 22 is an L-shaped trip member 38. End 40 of the trip member extends externally of the brush holder for connection to a power source not shown. The other end 41 is disposed within the upper chamber at an acute angle to the horizontal. As best seen in N04, the trip member 38 is designed to be received in an aperture 42 in the brush arm 34. When the trip member is so engaged, a current path exists from the trip member through the brush arm 34 to brush 30 and to the commutator 32.
  • a locking tab 44 is provided on the trip member. This position facilitates assembly of the unit by restraining the coil spring while the brush and armature are installed.
  • the trip member 38 is depressed sufficiently to release the brush arm 34 from the tab. The unit is then ready for operation and appears as illustrated in FIG. 3.
  • the brush being preferably formed of carbon, will wear against the armature. This reduction in size is compensated for by the expansion of coil spring 36 thereby maintaining good electrical contact.
  • the brush and brush holder thus move horizontally in the main channel 24 towards the commutator 32 due to the action of the coil spring.
  • the brush arm When the brush 30 wears down to a predetermined size, as shown in FIG. 5, the brush arm will reach a point just beyond 41 of the trip member 38 releasing the trip member from the aperture 42 of the brush arm.
  • the trip member is mounted in the upper chamber at a slight angle to the horizontal sufficient to bias it away from the brush arm. Accordingly, when the brush arm moves beyond end 41, the trip member rapidly moves away from and out of contact with the brush arm, as indicated by the arrow in FIG. 5. This is effective for interrupting current flow to the motor.
  • the brush holder causes the tool to turn off and remain off until a new brush is installed and the trip member is once again captured in the aperture 42. This prevents damage to the motor which would ordinarily be caused by continuing to use the tool when a brush is completely worn out or is not being maintained in good electrical contact with the commutator.
  • a brush housing 50 has a channel 52 adapted to receive a coil spring 54, a current conducting contact member 56 and a brush 30.
  • the current conducting contact member 56 is not bonded to the brush 30 but is merely sandwiched between the spring and the brush.
  • a notched portion 58 and a tab portion 60 are adapted to engage stops 62 and 64 provided on the housing 50 as will be explained.
  • Current is supplied to the brush 30 from contact member 56 which is connected to a cable 61 from the power source.
  • the brush and contact member 56 move toward the commutator as the brush wears down to maintain good electrical contact therewith.
  • the brush 30 has worn down to the size shown in FIGS. 9 and 10
  • the brush will be outside of the brush holder and unsupported.
  • the brush will therefore rapidly rotate away from the brush holder due to its frictional engagement with the commutator.
  • the notch 58 and tab 60 of the contact member 56 will engage the stops 62 and 64 preventing further movement of the contact member toward the commutator.
  • An insulating air gap will therefore exist between the commutator and the contact member 56, for interrupting the current flow.
  • the mating surface 66 of contact member 56 and the brush end may be curved.
  • the brush shown in FIG. 11 will be flung away in one piece.
  • the back portion of the brush may have slots cut into it at an appropriate depth.
  • the commutator will have worn the brush down to the slots and it will break up into pieces as it moves out of the brush holder.
  • a housing 70 has a main channel 72 containing a coil spring 74, a wedge contact 76 and a brush 78.
  • a compartment 80 adapted to receive the wedge contact 76 therein is located at one end of the housing 70.
  • Current is supplied from a power source via cable 82 through the wedge contact 76 to the brush 78 and commutator 32.
  • the wedge contact 76 is beveled along a bottom surface thereof and has an insulating layer 84 affixed to the beveled surface. As shown in FIG. 13, the spring 74 urges the brush 78 into contact with the commutator and at the same time urges the wedge contact 76 upwardly. Prior to the brush wearing down to a predetermined size the wedge is prevented from moving upwardly due to a pair of ledges 86 and 88 abutting against shoulder 90 and 92 of the wedge contact (FIG. 19). These ledges extend parallel to the main chamber.
  • the spring 74 is substantially compressed and the wedge contact is in electrical contact with the brush 78.
  • the spring expands and the wedge contact and brush move towards the commutator as shown in FIG. 15.
  • the wedge contact 76 is released from the ledges 86 and 88 and begins moving upwardly into the chamber 80.
  • the electrical contact surface area between the brush and wedge begins to decrease along the interface 81.
  • the wedge contact has moved rapidly and completely out of the main channel into the chamber 80 thereby to interrupt current flow to the commutator.
  • the insulating layer 84 provided along the beveled surface of the wedge contact prevents a sneak current path through the coil spring 74 to the brush and armature. The movement of the wedge out of contact with the brush requires at the most approximately one second to clear the ledges and pop out of the main channel.
  • a brush holder assembly which interrupts current flow from a power source to an electric motor commutator comprising:
  • said brush means includes a brush, and a current conducting brush arm attached to said brush;
  • said disconnecting means includes a current conducting trip member retained by said brush arm for providing said current flow and which is released from said brush arm when said brush wears down to said predetermined size.
  • the brush holder of claim 5 further including:
  • a contact member for conducting current from said source to said brush, said member moving with said brush;
  • stops positioned within said holder for restraining said contact member from contacting said commutator when said brush moves out of said holder.
  • a wedge contact for conducting current from said source to said brush means until said predetermined size is reached, said wedge contact thereafter moving in a direction away from said brush means and out of electrical contact therewith to discontinue current flow.
  • said urging means also causing said wedge contact to move away from and out of electrical contact with said brush when said predetermined size isreached.
  • a brush holder assembly which automatically interrupts current flow from a power source to an electric motor commutator comprising:
  • spring means for urging said brush into electrical contact with said commutator and for causing said wedge contact to move away from and out of electrical contact with said brush when the latter has worn down to a predetermined size.

Landscapes

  • Motor Or Generator Current Collectors (AREA)
US435323A 1974-01-21 1974-01-21 Current interrupting brush holder assembly Expired - Lifetime US3898492A (en)

Priority Applications (8)

Application Number Priority Date Filing Date Title
US435323A US3898492A (en) 1974-01-21 1974-01-21 Current interrupting brush holder assembly
CA214,843A CA1019799A (en) 1974-01-21 1974-11-28 Current interrupting brush holder assembly
AU76533/74A AU7653374A (en) 1974-01-21 1974-12-17 Current interrupting brush holder assembly
CH20875A CH592968A5 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1974-01-21 1975-01-09
IT47614/75A IT1032204B (it) 1974-01-21 1975-01-10 Gruppo porta spazzole capace di interrompere la corrente
DE19752502105 DE2502105A1 (de) 1974-01-21 1975-01-20 Stromunterbrechende buerstehaltevorrichtung
FR7501629A FR2258720B1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1974-01-21 1975-01-20
JP50009198A JPS50102804A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1974-01-21 1975-01-21

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US435323A US3898492A (en) 1974-01-21 1974-01-21 Current interrupting brush holder assembly

Publications (1)

Publication Number Publication Date
US3898492A true US3898492A (en) 1975-08-05

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Family Applications (1)

Application Number Title Priority Date Filing Date
US435323A Expired - Lifetime US3898492A (en) 1974-01-21 1974-01-21 Current interrupting brush holder assembly

Country Status (8)

Country Link
US (1) US3898492A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
JP (1) JPS50102804A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
AU (1) AU7653374A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
CA (1) CA1019799A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
CH (1) CH592968A5 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
DE (1) DE2502105A1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
FR (1) FR2258720B1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
IT (1) IT1032204B (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4074162A (en) * 1976-06-24 1978-02-14 Dynamics Corporation Of America Brush spring assembly
US4172988A (en) * 1977-08-02 1979-10-30 Towmotor Corporation Brush wear indicating means with engageable electrical contacts
US4246508A (en) * 1978-12-22 1981-01-20 Skil Corporation Brush holder assemblies for small electric motors
US4266155A (en) * 1979-09-10 1981-05-05 The Singer Company Brush holder assembly
US4316186A (en) * 1980-02-06 1982-02-16 Eltra Corporation Brush wear detection and warning system
US4344072A (en) * 1979-12-10 1982-08-10 Harper Jr Harold L Worn brush indicator
US20080303372A1 (en) * 2001-12-18 2008-12-11 Cutsforth Products, Inc. Brush holder apparatus, brush assembly, and method
US20110169383A1 (en) * 2008-09-18 2011-07-14 Spal Automotive S.R.L. Electric motor and brush holder spring
US8922092B2 (en) 2011-03-07 2014-12-30 Cutsforth, Inc. Brush holder assembly with quick disconnect terminal
US11996664B2 (en) 2020-12-01 2024-05-28 Cutsforth, Inc. Brush holder assembly
US12015229B2 (en) 2020-11-04 2024-06-18 Cutsforth, Inc. Brush holder assembly

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS622477A (ja) * 1985-06-28 1987-01-08 株式会社東芝 スリツプリング
DE4323413C2 (de) * 1993-07-13 1997-01-30 Atlanta Elektrosysteme Gmbh & Kontaktvorrichtung für eine Kohlebürste
DE10320236A1 (de) * 2003-05-07 2004-12-02 Schunk Kohlenstofftechnik Gmbh Kohlebürste

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2775717A (en) * 1954-03-08 1956-12-25 Laing Nikolaus Sequentially feeding brush holder for commutator type electrical machines
US2842693A (en) * 1957-05-17 1958-07-08 Gen Electric Support fixture
US2851622A (en) * 1955-10-13 1958-09-09 Whirlpool Co Electric motor
US3108201A (en) * 1960-07-08 1963-10-22 Skil Corp Brush holder assembly
US3466481A (en) * 1965-01-30 1969-09-09 Ringsdorff Werke Gmbh Brush holder with gripping lever for electrical machines
US3480814A (en) * 1968-06-03 1969-11-25 Black & Decker Mfg Co Brush holder assembly with insert
US3513343A (en) * 1968-03-11 1970-05-19 Black & Decker Mfg Co Brush holder assembly
US3523288A (en) * 1968-03-20 1970-08-04 Harris A Thompson Brush wear indicator
US3534206A (en) * 1969-10-09 1970-10-13 Carbone Corp The Carbon brush assembly
US3710160A (en) * 1971-08-12 1973-01-09 Dynamics Corp America Motor brush assembly

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2775717A (en) * 1954-03-08 1956-12-25 Laing Nikolaus Sequentially feeding brush holder for commutator type electrical machines
US2851622A (en) * 1955-10-13 1958-09-09 Whirlpool Co Electric motor
US2842693A (en) * 1957-05-17 1958-07-08 Gen Electric Support fixture
US3108201A (en) * 1960-07-08 1963-10-22 Skil Corp Brush holder assembly
US3466481A (en) * 1965-01-30 1969-09-09 Ringsdorff Werke Gmbh Brush holder with gripping lever for electrical machines
US3513343A (en) * 1968-03-11 1970-05-19 Black & Decker Mfg Co Brush holder assembly
US3523288A (en) * 1968-03-20 1970-08-04 Harris A Thompson Brush wear indicator
US3480814A (en) * 1968-06-03 1969-11-25 Black & Decker Mfg Co Brush holder assembly with insert
US3534206A (en) * 1969-10-09 1970-10-13 Carbone Corp The Carbon brush assembly
US3710160A (en) * 1971-08-12 1973-01-09 Dynamics Corp America Motor brush assembly

Cited By (30)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4074162A (en) * 1976-06-24 1978-02-14 Dynamics Corporation Of America Brush spring assembly
US4172988A (en) * 1977-08-02 1979-10-30 Towmotor Corporation Brush wear indicating means with engageable electrical contacts
US4246508A (en) * 1978-12-22 1981-01-20 Skil Corporation Brush holder assemblies for small electric motors
US4266155A (en) * 1979-09-10 1981-05-05 The Singer Company Brush holder assembly
US4344072A (en) * 1979-12-10 1982-08-10 Harper Jr Harold L Worn brush indicator
US4316186A (en) * 1980-02-06 1982-02-16 Eltra Corporation Brush wear detection and warning system
US8179014B2 (en) 2001-12-18 2012-05-15 Cutsforth Products, Inc. Brush holder apparatus, brush assembly, and method
US8546993B2 (en) 2001-12-18 2013-10-01 Cutsforth, Inc. Brush holder apparatus, brush assembly, and method
US7564160B2 (en) 2001-12-18 2009-07-21 Cutsforth Products, Inc. Brush holder apparatus, brush assembly, and method
US20100133950A1 (en) * 2001-12-18 2010-06-03 Cutsforth Products, Inc. Brush holder apparatus, brush assembly, and method
US7768174B2 (en) 2001-12-18 2010-08-03 Cutsforth Products, Inc. Brush holder apparatus, brush assembly, and method
US7880363B2 (en) 2001-12-18 2011-02-01 Cutsforth Products, Inc. Brush holder apparatus, brush assembly, and method
US20090001842A1 (en) * 2001-12-18 2009-01-01 Cutsforth Products, Inc. Brush holder apparatus, brush assembly, and method
US7990018B2 (en) 2001-12-18 2011-08-02 Cutsforth Products, Inc. Brush holder apparatus, brush assembly, and method
US20080303372A1 (en) * 2001-12-18 2008-12-11 Cutsforth Products, Inc. Brush holder apparatus, brush assembly, and method
US9350130B2 (en) 2001-12-18 2016-05-24 Cutsforth, Inc. Brush holder apparatus, brush assembly, and method
US10199790B2 (en) 2001-12-18 2019-02-05 Cutsforth, Inc. Brush holder apparatus, brush assembly, and method
US9590375B2 (en) 2001-12-18 2017-03-07 Cutsforth, Inc. Brush holder apparatus, brush assembly, and method
US9287676B2 (en) 2001-12-18 2016-03-15 Cutsforth, Inc. Brush holder apparatus, brush assembly, and method
US9287675B2 (en) 2001-12-18 2016-03-15 Cutsforth, Inc. Brush holder apparatus, brush assembly, and method
US9287674B2 (en) 2001-12-18 2016-03-15 Cutsforth, Inc. Brush holder apparatus, brush assembly, and method
US9293881B2 (en) 2001-12-18 2016-03-22 Cutsforth, Inc. Brush holder apparatus, brush assembly, and method
US9293880B2 (en) 2001-12-18 2016-03-22 Cutsforth, Inc. Brush holder apparatus, brush assembly, and method
US9293879B2 (en) 2001-12-18 2016-03-22 Cutsforth, Inc. Brush holder apparatus, brush assembly, and method
US20110169383A1 (en) * 2008-09-18 2011-07-14 Spal Automotive S.R.L. Electric motor and brush holder spring
US8981616B2 (en) * 2008-09-18 2015-03-17 Spal Automotive S.R.L. Electric motor and brush holder spring
US8922092B2 (en) 2011-03-07 2014-12-30 Cutsforth, Inc. Brush holder assembly with quick disconnect terminal
USRE47563E1 (en) 2011-03-07 2019-08-06 Cutsforth, Inc. Brush holder assembly with quick disconnect terminal
US12015229B2 (en) 2020-11-04 2024-06-18 Cutsforth, Inc. Brush holder assembly
US11996664B2 (en) 2020-12-01 2024-05-28 Cutsforth, Inc. Brush holder assembly

Also Published As

Publication number Publication date
IT1032204B (it) 1979-05-30
AU7653374A (en) 1976-06-17
DE2502105A1 (de) 1975-11-06
CA1019799A (en) 1977-10-25
JPS50102804A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1975-08-14
CH592968A5 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1977-11-15
FR2258720A1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1975-08-18
FR2258720B1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1978-10-06

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