CA1215653A - Railway vehicle brake shoe - Google Patents
Railway vehicle brake shoeInfo
- Publication number
- CA1215653A CA1215653A CA000444947A CA444947A CA1215653A CA 1215653 A CA1215653 A CA 1215653A CA 000444947 A CA000444947 A CA 000444947A CA 444947 A CA444947 A CA 444947A CA 1215653 A CA1215653 A CA 1215653A
- Authority
- CA
- Canada
- Prior art keywords
- depressions
- openings
- back plate
- composition
- clusters
- 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
Links
Landscapes
- Braking Arrangements (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A composition brake shoe comprising a rigid back plate having an outer convex surface and an inner concave surface, the rigid back plate including a plurality of depressions formed in the back plate, and clusters of openings disposed about and communicating with each of the depressions, a molded brake shoe composition including a heat curable material super-posed on the underside of the back plate, the heat curable material disposed in and through each of openings of the clusters and within the depressions associated with each of the clusters thereby to provide ties between the openings associated with each depression whereby the molded brake composition is held in face to face engagement with the back plate.
A composition brake shoe comprising a rigid back plate having an outer convex surface and an inner concave surface, the rigid back plate including a plurality of depressions formed in the back plate, and clusters of openings disposed about and communicating with each of the depressions, a molded brake shoe composition including a heat curable material super-posed on the underside of the back plate, the heat curable material disposed in and through each of openings of the clusters and within the depressions associated with each of the clusters thereby to provide ties between the openings associated with each depression whereby the molded brake composition is held in face to face engagement with the back plate.
Description
issue RAILWAY VEHICLE BRAKE SHOE
Field of the Invention The present invention relates to composition brake shoes and more particularly to an improved backing plate structure for fastening the composition brake material thereto.
Background of the Invention Composition brake shoes of the type to which the present invention relates generally comprise a molded body of friction material including a heat curable binder such as a therm setting resin or a vulcanizable rubber. The molded friction body is adhered to a rigid backing plate such as steel or the like. A backing strip is usually interposed Boone the friction composition and the backing plate to compensate for the different rates of coefficient of expansion between the backing plate and the friction material so that the composition material does not delaminate during normal braking causing-the backing plate and composition to become heated.
Heretofore it has been common practice to provide the rigid backing plate with a plurality of generally circularly openings through which the binder in the backing strip and or of the composition brake material is extruded or forced during the brake shoe molding and assembly process in the well known manner. The binder thus extruded, cures in the or of buttons disposed in the openings. The buttons serve to help resist shearing forces at the interface ox the molded friction composition and the backing plates. However, SO
the button-like projections provide little if any resistance against separation of the interface so that it is necessary to provide an adhesive at the interface to bond the backing strip and the friction composition thereto.
By the present disclosure it is proposed to provide a mechanical attachment arrangement for fastening the friction member to the backing plate of the composition shoe.
This is accomplished generally by providing the backing plate with a plurality of depressions about which an array or cluster of openings are disposed. The openings communicate with the depressions such that the heat responsive binder in a backing strip during the molding and assembly process flows through the openings and fills the depressions.
Upon curing the binder forms a positive tie extending through and between the openings to prevent separation of the molded friction composition and the backing plate.
Brief Description of the Drawings - FIG. 1 is a front elevation view of a composition brake shoe embodying the structure of the present invention.
FIG. 2 is a top plan view of the brake shoe with some of the parts being broken away to show underlying details of structure.
FIG. 3 is a cross sectional view taken generally along the lines 3-3 of FIG. 2 with parts broken away to show underlying details of structure.
l Z 15 I 5 3 issue a cross sectional view taken gen'er~l'ly,'along. ;'. '" '..
. the lines 4-4 of FIG. 2 with parts broken away show .,:
. underlying details of.s~ructure. ': . : '. .
, . , . ................................... : .
Description of the Preferred Embodiment Referring now to the drawings there is shown a composition brake shoe 10 of the general type used in railway vehicles such as locomotives, freight and transit vehicles. The composition brake shoe comprises generally a back plate 12 to the underside of which there it adhered a backing strip 14 and a friction member 16.
The backing plate 12 is made from a rigid material such as steel stamping or the like and is generally arcuately shaped about a center common with a center of a railway wheel with which the brake shoe is adapted to be used. The plate 12 includes an upper convex surface 18 and an inner lo concave surface 20 on which the backing strip 14 is superposed in face-to-face relationship. An inverted U-shaped key attachment bracket 21 is located at the lengthwise center ox the plate and positioning lugs 23 are provided adjacent the ends of the plate. Spanning the space between the legs ox the lug 21 and secured to the back plate is a tie plate 27.
The backing strip 14 serves to provide a layer of material which permits different rates of expansion and contraction between the back plate 12 and the friction member 16 as caused by the heating and cooling of the brake shoe in normal operation.
The backing sheet or pad I conventionally includes a heat responsive binder such as a thermosetting resin or - :12~ 3 : -vulcanizable tubber; dispersed within the binder is no-.- ,:: . , . .;-, .-, .:;
inorcing media such as armed or glass fibers, or the like.
. . . .. . - . . . . . , , . .: . .. .
The binder may be any one of the commonly available compost itchiness including as mentioned above a thermosetting resin or vulcanizable rubber either clone or in combination. The composition may include the usual rubber curing agents such as sulfur, be~zothiazyl disulfide, tetramethyl thrum disulfide, tetraethyl thrum disallowed or the like.
The jacking sheet or pad 14 may be adhered in face-to-face engagement with the underside by an adhesive which misapplied thereon and provides a bond as more fully to be explained hereinafter. Suitable adhesives may be finlike, nitrite finlike, bromated dichlorobutadiene or other types of rubber to metal adhesives.
The friction member of body 16 may be ox any of the well-known and available compositions suitable for use as friction member for engagement with a railway wheel. Such compositions are each characterized by the use of binder in which there is dispersed particles of friction material such as iron grit and alumina silicate and fillets such as clay, burettes, graphite or other similar carbonaceous materials and materials which serve as friction modifiers.
The binder composition as heretofore generally described may be either a synthetic rubber or thermosetting resins.
The binder composition includes the usual curing agents and/or solvents for the thermosetting resin such as Tulane, alcohol and the like.
The friction member 16 is formed as by molding the mixed friction shoe composition in a press and subjecting ;5653 ; `:
.... .. . ...... . . ...... .... . . . ....... ...... . ............... . . ..
... 'the c~mpressed,.composition to an elevated temperature foe' ' ,' I' ''' " 'su~f~ëient peridot ure'or set the b~naer.~'"'.. ;' :. ' '; I' ', `- In practice the friction member issue formed and'simul- - ''' .:
tonsil bonded to the steel back plate 12. To this end -- 5 -the back plate 12 including the backing pad 14 and the .
friction shoe composition are inserted into a press whereupon the composition is compressed and heat applied thereto. The heat responsive constituents of the composition and the back plate 12 are rendered plowable. When heated the thermosetting lo and/or rubber composition cures and hardens in the usual manner. The binders at the interface of the backing strip I and the friction member 16 are then commingled. At the same time the adhesive on the underside of the metal back plate 12 which may also be heat curable serves to bond the hardening friction member thereto.
With this structure it is to be noted-that the jacking pad 14 remains interposed between the friction member and the back plate 12 so as to perform its function. As mentioned heretofore the pad 14 serves to permit relative and different expansion rates of the back plate 12 and the friction member 16. Thus upon braking the different thermal expansions ox the back plate 12 and friction member 16 are compensated for by the pad 14 without shearing or separating at the adhesive interface of the back plate 12.
do so A 25 In accordance with the present~i~eo*~on it is proposed to provide a mechanical tie or lock for retaining the friction member 16 fastened to the back plate 12. To this as shown the back plats 14 includes a plurality ox dimples or depressions 22 and 24. The depressions 22 and 24 are formed by displacing ... I. . . the upper and inner faces toward the friction member and` the ac~in'g~paa;.'`' Pyre ivy Jo " but no greater than 3/8". As shown the dëpxesslons 22 are substantially circular and include a base 26 and an ~~ 5 inclined side wall Z8 which extends between the upper and inner surfaces 18 and 20. The depressions 24 are generally rectangular and include a base 32, end walls 34 and side walls 36. the end and side walls 34 and 36 respectively also extend integrally between the upper and inner surfaces of the plate The depressions 22 are located between the key attachment bracket 21 and thy locating lugs and the rectangular depressions 24 along side the locating lugs adjacent the respective ends of the plate 12.
Associated with each of the depressions 22 are a array or cluster of openings 38 which are disposed about the circumference of the former. As shown each array 38 includes three openings 40 which are uniformly angularly spaced about the respective depression 22. Each opening 40 preferably extends from the outer face 18 of the plate and into the side wall 28 so that the base 26 of the depression lie on common tangent.
Each of the rectangular depressions 22 include an array or cluster 41 of two openings 42. The openings 22 are located adjacent the end walls 34 and extend from the base 32 and into the inner undimpled outer race of the backing plate.
During the assembly of the brake shoe 10 as heretofore generally described the thermal responsive binder of the back pad 14 is free to flow through the openings 40 and 42 ., .. . . ' . , ! ' ' ' ': ' .-.... : and Jill the.respecti~e.de.p~ession~ 22 and..24...Up~n curing '' he Sweeney with the binder composition which extends through the openings 40 and 42 about the circular and rectangular depressions 22 ~` 5 and 24 and form in the nature of attachment arms 44. The arms 44 which are integral with the back pad 14 and the tie portions 46 and 48 disposed in the respective depressions 22 and 24 lie in opposing relationship to the remainder of the pad 14 to form a mechanical lock preventing separation of the pad 14 and the friction material 16 from the metal plate 12.
It is to be noted that with the openings 40 and 42 extending along the side walls Z8 and 34 and into bases 30 and 32 of the depressions, the cross sectional area of the binder material within openings is maximized and thereby provide a tie having a maximum resistance in tension and shear.
Field of the Invention The present invention relates to composition brake shoes and more particularly to an improved backing plate structure for fastening the composition brake material thereto.
Background of the Invention Composition brake shoes of the type to which the present invention relates generally comprise a molded body of friction material including a heat curable binder such as a therm setting resin or a vulcanizable rubber. The molded friction body is adhered to a rigid backing plate such as steel or the like. A backing strip is usually interposed Boone the friction composition and the backing plate to compensate for the different rates of coefficient of expansion between the backing plate and the friction material so that the composition material does not delaminate during normal braking causing-the backing plate and composition to become heated.
Heretofore it has been common practice to provide the rigid backing plate with a plurality of generally circularly openings through which the binder in the backing strip and or of the composition brake material is extruded or forced during the brake shoe molding and assembly process in the well known manner. The binder thus extruded, cures in the or of buttons disposed in the openings. The buttons serve to help resist shearing forces at the interface ox the molded friction composition and the backing plates. However, SO
the button-like projections provide little if any resistance against separation of the interface so that it is necessary to provide an adhesive at the interface to bond the backing strip and the friction composition thereto.
By the present disclosure it is proposed to provide a mechanical attachment arrangement for fastening the friction member to the backing plate of the composition shoe.
This is accomplished generally by providing the backing plate with a plurality of depressions about which an array or cluster of openings are disposed. The openings communicate with the depressions such that the heat responsive binder in a backing strip during the molding and assembly process flows through the openings and fills the depressions.
Upon curing the binder forms a positive tie extending through and between the openings to prevent separation of the molded friction composition and the backing plate.
Brief Description of the Drawings - FIG. 1 is a front elevation view of a composition brake shoe embodying the structure of the present invention.
FIG. 2 is a top plan view of the brake shoe with some of the parts being broken away to show underlying details of structure.
FIG. 3 is a cross sectional view taken generally along the lines 3-3 of FIG. 2 with parts broken away to show underlying details of structure.
l Z 15 I 5 3 issue a cross sectional view taken gen'er~l'ly,'along. ;'. '" '..
. the lines 4-4 of FIG. 2 with parts broken away show .,:
. underlying details of.s~ructure. ': . : '. .
, . , . ................................... : .
Description of the Preferred Embodiment Referring now to the drawings there is shown a composition brake shoe 10 of the general type used in railway vehicles such as locomotives, freight and transit vehicles. The composition brake shoe comprises generally a back plate 12 to the underside of which there it adhered a backing strip 14 and a friction member 16.
The backing plate 12 is made from a rigid material such as steel stamping or the like and is generally arcuately shaped about a center common with a center of a railway wheel with which the brake shoe is adapted to be used. The plate 12 includes an upper convex surface 18 and an inner lo concave surface 20 on which the backing strip 14 is superposed in face-to-face relationship. An inverted U-shaped key attachment bracket 21 is located at the lengthwise center ox the plate and positioning lugs 23 are provided adjacent the ends of the plate. Spanning the space between the legs ox the lug 21 and secured to the back plate is a tie plate 27.
The backing strip 14 serves to provide a layer of material which permits different rates of expansion and contraction between the back plate 12 and the friction member 16 as caused by the heating and cooling of the brake shoe in normal operation.
The backing sheet or pad I conventionally includes a heat responsive binder such as a thermosetting resin or - :12~ 3 : -vulcanizable tubber; dispersed within the binder is no-.- ,:: . , . .;-, .-, .:;
inorcing media such as armed or glass fibers, or the like.
. . . .. . - . . . . . , , . .: . .. .
The binder may be any one of the commonly available compost itchiness including as mentioned above a thermosetting resin or vulcanizable rubber either clone or in combination. The composition may include the usual rubber curing agents such as sulfur, be~zothiazyl disulfide, tetramethyl thrum disulfide, tetraethyl thrum disallowed or the like.
The jacking sheet or pad 14 may be adhered in face-to-face engagement with the underside by an adhesive which misapplied thereon and provides a bond as more fully to be explained hereinafter. Suitable adhesives may be finlike, nitrite finlike, bromated dichlorobutadiene or other types of rubber to metal adhesives.
The friction member of body 16 may be ox any of the well-known and available compositions suitable for use as friction member for engagement with a railway wheel. Such compositions are each characterized by the use of binder in which there is dispersed particles of friction material such as iron grit and alumina silicate and fillets such as clay, burettes, graphite or other similar carbonaceous materials and materials which serve as friction modifiers.
The binder composition as heretofore generally described may be either a synthetic rubber or thermosetting resins.
The binder composition includes the usual curing agents and/or solvents for the thermosetting resin such as Tulane, alcohol and the like.
The friction member 16 is formed as by molding the mixed friction shoe composition in a press and subjecting ;5653 ; `:
.... .. . ...... . . ...... .... . . . ....... ...... . ............... . . ..
... 'the c~mpressed,.composition to an elevated temperature foe' ' ,' I' ''' " 'su~f~ëient peridot ure'or set the b~naer.~'"'.. ;' :. ' '; I' ', `- In practice the friction member issue formed and'simul- - ''' .:
tonsil bonded to the steel back plate 12. To this end -- 5 -the back plate 12 including the backing pad 14 and the .
friction shoe composition are inserted into a press whereupon the composition is compressed and heat applied thereto. The heat responsive constituents of the composition and the back plate 12 are rendered plowable. When heated the thermosetting lo and/or rubber composition cures and hardens in the usual manner. The binders at the interface of the backing strip I and the friction member 16 are then commingled. At the same time the adhesive on the underside of the metal back plate 12 which may also be heat curable serves to bond the hardening friction member thereto.
With this structure it is to be noted-that the jacking pad 14 remains interposed between the friction member and the back plate 12 so as to perform its function. As mentioned heretofore the pad 14 serves to permit relative and different expansion rates of the back plate 12 and the friction member 16. Thus upon braking the different thermal expansions ox the back plate 12 and friction member 16 are compensated for by the pad 14 without shearing or separating at the adhesive interface of the back plate 12.
do so A 25 In accordance with the present~i~eo*~on it is proposed to provide a mechanical tie or lock for retaining the friction member 16 fastened to the back plate 12. To this as shown the back plats 14 includes a plurality ox dimples or depressions 22 and 24. The depressions 22 and 24 are formed by displacing ... I. . . the upper and inner faces toward the friction member and` the ac~in'g~paa;.'`' Pyre ivy Jo " but no greater than 3/8". As shown the dëpxesslons 22 are substantially circular and include a base 26 and an ~~ 5 inclined side wall Z8 which extends between the upper and inner surfaces 18 and 20. The depressions 24 are generally rectangular and include a base 32, end walls 34 and side walls 36. the end and side walls 34 and 36 respectively also extend integrally between the upper and inner surfaces of the plate The depressions 22 are located between the key attachment bracket 21 and thy locating lugs and the rectangular depressions 24 along side the locating lugs adjacent the respective ends of the plate 12.
Associated with each of the depressions 22 are a array or cluster of openings 38 which are disposed about the circumference of the former. As shown each array 38 includes three openings 40 which are uniformly angularly spaced about the respective depression 22. Each opening 40 preferably extends from the outer face 18 of the plate and into the side wall 28 so that the base 26 of the depression lie on common tangent.
Each of the rectangular depressions 22 include an array or cluster 41 of two openings 42. The openings 22 are located adjacent the end walls 34 and extend from the base 32 and into the inner undimpled outer race of the backing plate.
During the assembly of the brake shoe 10 as heretofore generally described the thermal responsive binder of the back pad 14 is free to flow through the openings 40 and 42 ., .. . . ' . , ! ' ' ' ': ' .-.... : and Jill the.respecti~e.de.p~ession~ 22 and..24...Up~n curing '' he Sweeney with the binder composition which extends through the openings 40 and 42 about the circular and rectangular depressions 22 ~` 5 and 24 and form in the nature of attachment arms 44. The arms 44 which are integral with the back pad 14 and the tie portions 46 and 48 disposed in the respective depressions 22 and 24 lie in opposing relationship to the remainder of the pad 14 to form a mechanical lock preventing separation of the pad 14 and the friction material 16 from the metal plate 12.
It is to be noted that with the openings 40 and 42 extending along the side walls Z8 and 34 and into bases 30 and 32 of the depressions, the cross sectional area of the binder material within openings is maximized and thereby provide a tie having a maximum resistance in tension and shear.
Claims (3)
PROPERTY OR PRIVILEGE IS CLAIMED ARE Defined AS FOLLOWS:
1. A composition brake shoe comprising:
a rigid back plate having an outer convex surface and an inner concave surface, said rigid back plate including a plurality of depressions formed within one of said surfaces in said back plate, each of the said depressions having circumferential walls, and clusters of openings disposed in and communicating with each of said depressions, at least one of said clusters comprising at least three equally spaced openings extending into the sidewalls of a circular depression having a circular base and side walls, and a molded brake shoe composition including a heat curable backing pad material superposed on the other of said surfaces of said back plate, said heat curable backing pad material flowed from around said depressions and disposed in and through each of the openings of said clusters and filling said depressions associated with each of said clusters thereby to provide ties between the openings associated with each depression and wherein each opening in said circular depression is directly tied to at least two other openings whereby said molded brake composition is held in face to face engagement with said back plate.
a rigid back plate having an outer convex surface and an inner concave surface, said rigid back plate including a plurality of depressions formed within one of said surfaces in said back plate, each of the said depressions having circumferential walls, and clusters of openings disposed in and communicating with each of said depressions, at least one of said clusters comprising at least three equally spaced openings extending into the sidewalls of a circular depression having a circular base and side walls, and a molded brake shoe composition including a heat curable backing pad material superposed on the other of said surfaces of said back plate, said heat curable backing pad material flowed from around said depressions and disposed in and through each of the openings of said clusters and filling said depressions associated with each of said clusters thereby to provide ties between the openings associated with each depression and wherein each opening in said circular depression is directly tied to at least two other openings whereby said molded brake composition is held in face to face engagement with said back plate.
2. The invention as defined in Claim 1 wherein at least one of said depressions is substantially rectangular and includes a base, end walls and side walls, and wherein said openings extend into said end walls.
3. The invention as defined in Claim 1. wherein each of said depressions includes an upstanding wall and said openings extend into said wall.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US46331083A | 1983-02-02 | 1983-02-02 | |
| US463,310 | 1983-02-02 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1215653A true CA1215653A (en) | 1986-12-23 |
Family
ID=23839659
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000444947A Expired CA1215653A (en) | 1983-02-02 | 1984-01-09 | Railway vehicle brake shoe |
Country Status (6)
| Country | Link |
|---|---|
| AR (1) | AR231180A1 (en) |
| AU (1) | AU564915B2 (en) |
| BR (1) | BR8400236A (en) |
| CA (1) | CA1215653A (en) |
| IN (1) | IN159221B (en) |
| MX (1) | MX158834A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4781275A (en) * | 1984-04-30 | 1988-11-01 | Amsted Industries Incorporated | Composition railway brake shoe |
-
1984
- 1984-01-09 CA CA000444947A patent/CA1215653A/en not_active Expired
- 1984-01-16 AR AR29543484A patent/AR231180A1/en active
- 1984-01-30 MX MX20017784A patent/MX158834A/en unknown
- 1984-02-01 AU AU23982/84A patent/AU564915B2/en not_active Ceased
- 1984-02-01 IN IN61/MAS/84A patent/IN159221B/en unknown
- 1984-04-19 BR BR8400236A patent/BR8400236A/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| AU564915B2 (en) | 1987-09-03 |
| AU2398284A (en) | 1984-08-09 |
| MX158834A (en) | 1989-03-16 |
| BR8400236A (en) | 1984-09-04 |
| AR231180A1 (en) | 1984-09-28 |
| IN159221B (en) | 1987-04-11 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |