US3572476A - Shoe retracting system for internal shoe drum brakes, and brakes including same - Google Patents

Shoe retracting system for internal shoe drum brakes, and brakes including same Download PDF

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Publication number
US3572476A
US3572476A US793313*A US3572476DA US3572476A US 3572476 A US3572476 A US 3572476A US 3572476D A US3572476D A US 3572476DA US 3572476 A US3572476 A US 3572476A
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United States
Prior art keywords
lever
shoe
brake
shoes
cam member
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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
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US793313*A
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English (en)
Inventor
Bernard Laverdant
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DBA SA
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DBA SA
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Publication date
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Publication of US3572476A publication Critical patent/US3572476A/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D51/00—Brakes with outwardly-movable braking members co-operating with the inner surface of a drum or the like
    • F16D51/16—Brakes with outwardly-movable braking members co-operating with the inner surface of a drum or the like shaped as brake-shoes pivoted on a fixed or nearly-fixed axis
    • F16D51/18—Brakes with outwardly-movable braking members co-operating with the inner surface of a drum or the like shaped as brake-shoes pivoted on a fixed or nearly-fixed axis with two brake-shoes

Definitions

  • a drum brake which includes a lever pivotally attached to one of the shoes.
  • the lever has a hooked end whichis attached to one end of a return spring which is stretched between the shoes.
  • a cam member is rotatably mounted on the one shoe and includes an eccentric mounted thereon which engages a slot in the lever. Rotation of the cam member moves the lever from a first position in which the return spring is relaxed to a second position in which the spring is stressed to exert a force on the shoes.
  • the cam member is accessible from the exterior of the brake so that an appropriate tool may be used to rotate the cam member.
  • the present invention relates to a shoe retracting system for internal shoe drum brakes and it has for its principal object to provide means for easily hooking the usual shoe return spring or springs upon brake mounting and unhooking same upon brake dismounting. It is of a particular interest whenever the brake shoe webs display poor accessibility once the shoes are located in their operating position, as may be experienced with some kinds of internal shoe drum brakes comprising a double backing plate, which usually hinders the hooking of one or more prestressed springs on said brake shoes.
  • a more general object of the invention is to provide an internal shoe drum brake including a shoe retracting system according to the principles which will be set forth hereinafter.
  • a lever member pivotally connected at one end thereof to the brake shoe web and formed at its opposite end with a hook portion, this lever member being disposed generally transversely to the spring axis and being adapted to be pivoted by an associated positioning means between two distinct angular positions corresponding respectively to the stressed and to the unstressed condition of said return spring or springs.
  • the associated positioning means which is operable from the outside of the brake, consists of a rotating cam member carried by the brake shoe web and provided with an eccentric member which is slidably received in a slot or similar opening of the lever member so as to cause the latter to pivot from one of said angular positions to the other as said cam member is rotated about its axis by means of an appropriate tool.
  • the eccentric member By engaging the bottom portion of said slot, the eccentric member preferably determines at least one of said angular positions of the pivoting lever member, particularly that one which corresponds to the stressed condition of the associated ,retum spring; and, advantageously, this last-mentioned angular position will be reached for a displacement of the rotating cam member beyond that corresponding to the greatest elongation of the spring, thereby providing for a self-locking of the pivoting lever member in its operative position.
  • FIG. l is a simplified elevational view showing the shoes of an internal shoe drum brake and an associated shoe retracting system in accordance with the principles of this invention.
  • F 16. 2 is an enlarged scale view of the pivoting lever member and associated positioning means in both angular positions corresponding respectively to the stressed condition (in solid lines) and to the unstressed condition (in dotted lines) of the associated return spring.
  • FiG. 1 there is shown a pair of brake shoes 10,12 disposed in a known end-to-end relationship inside an internal shoe drum brake (not shown). These brake shoes are normally urged toward each other in a retracted position and held in abutting engagement with anchoring means or interconnecting struts (not shown) by one or more return springs 14 which are stretched therebetween. It will be observed that, whereas one end of the spring 14 is directly attached to the web of brake shoe 12, its other end is hooked on shoe 10 through the intermediary of a pivoting lever 16 shown in more detail on the view of FIG. 2.
  • the lever 16 is pivotally connected at its lower end to the web of brake shoe 10 through a pivot pin 18 and terminates at its upper end with a hook portion adapted to be engaged by the end of spring 14. lntermediate its ends, the lever is formed with an open slot 20 limited by a pair of parallel edges extending substantially radially with respect to pivot pin 18, and by a rounded interconnecting bottom portion; alternatively, the slot 20 could be closed at both ends without departing from the spirit of the invention. Between the edges of slot 20 is slidably received an eccentric pin 22 secured to a rotating cam 24 which is also carried by the web of brake shoe l0 and constitutes a positioning means for the pivoting lever 16.
  • the shaft of cam 24 projects through an opening in the backing plate of the brake an is so shaped as to be easily operable from the outside with an appropriate tool such as, for instance, a screwdriver,
  • the cam 24 can be rotated between two end positions both determined by the abutting engagement of the eccentric pin 22 with the bottom portion of slot 20.
  • the rotation of cam 24 causes the pin 22 to slidably engage the sides of slot 20 to pivot the lever 16 between two distinct angular positions; and the location of the respective centers of rotation as well as the general dimensions of the mechanism can be easily determined in such a manner that one of said angular positions (shown in dotted lines on FIG.
  • the shoes When assembling the brake, the shoes are first properly located on the backing plate with their pivoting lever or levers 16 in their inoperative position as shown in dotted lines on FlG. 2.
  • the return spring 14 can thus be hooked between the shoe 12 and the end of lever 16 on shoe 10 without difficulty since being in an unstressed condition.
  • the cam 24 will be rotated from the outside of the brake with a convenient tool in the direction of arrow A. This will cause the lever 16 to be progressively pivoted toward the left while simultaneously stressing the spring 14 until the latter reaches its greatest elongation, after what further rotation of the cam 24 will cause the eccentric pin 22 to be urged against the bottom portion of slot 20.
  • the lever 16 will thus be held, as explained above, in its operative angular position shown in solid lines on FIG. 2.
  • the preceding steps will, of course, have to be performed in a converse order for dismounting the brake.
  • each brake shoe with one or more pivoting levers, or by modifying the respective locations of the pivoting centers and hooking points, or by still replacing the rotating cam with any suitable equivalent means, and it should be understood that all of these modified embodiments are included in the scope of protection as defined by the following claims:
  • lever pivoting between a first position in which the spring is relatively relaxed to a second position in which the spring is stressed to exert a force on the shoes;
  • said positioning means including a slot in said lever, and a rotating cam member carried by said one shoe and having an eccentric member slidably received in the slot in said lever whereby rotation of the cam member pivots the lever between said first and second positions.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Braking Arrangements (AREA)
US793313*A 1968-01-26 1969-01-23 Shoe retracting system for internal shoe drum brakes, and brakes including same Expired - Lifetime US3572476A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR137591 1968-01-26

Publications (1)

Publication Number Publication Date
US3572476A true US3572476A (en) 1971-03-30

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ID=8645162

Family Applications (1)

Application Number Title Priority Date Filing Date
US793313*A Expired - Lifetime US3572476A (en) 1968-01-26 1969-01-23 Shoe retracting system for internal shoe drum brakes, and brakes including same

Country Status (6)

Country Link
US (1) US3572476A (it)
DE (1) DE1903397A1 (it)
ES (1) ES362915A1 (it)
FR (1) FR1562953A (it)
GB (1) GB1228343A (it)
SE (1) SE340018B (it)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4754853A (en) * 1986-06-20 1988-07-05 Shimano Industrial Company Limited Caliper brake for a bicycle
US4842104A (en) * 1983-12-09 1989-06-27 Lucas Industries Public Limited Company Internal shoe drum brake
US5261510A (en) * 1992-08-24 1993-11-16 Eaton Corporation Brake spring support pin with spring cam
US6732840B2 (en) * 2001-06-08 2004-05-11 Nisshinbo Industries Inc. Brake cable connecting apparatus for a drum brake device

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4116180C1 (en) * 1991-05-17 1992-11-26 Bergische Achsenfabrik Fr. Kotz & Soehne, 5276 Wiehl, De Drum brake for motor vehicle - has shoes held via spring and with peg to act as fulcrum for removal lever
DE102006044280B4 (de) * 2006-09-20 2008-11-06 Hermann Peters Gmbh & Co. Exzentrischer Spannstift und Bremsbacke für exzentrischen Spannstift sowie System aus Spannstift und Bremsbacke

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1663295A (en) * 1927-07-16 1928-03-20 Bendix Brake Co Brake
GB555581A (en) * 1941-03-31 1943-08-30 Wagner Electric Corp Assembling means for brake shoe retracting springs
US2621761A (en) * 1949-08-20 1952-12-16 Chrysler Corp Brake shoe adjusting and positioning means
US3203512A (en) * 1962-02-13 1965-08-31 Ferodo Sa Hydraulic drum brake

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1663295A (en) * 1927-07-16 1928-03-20 Bendix Brake Co Brake
GB555581A (en) * 1941-03-31 1943-08-30 Wagner Electric Corp Assembling means for brake shoe retracting springs
US2621761A (en) * 1949-08-20 1952-12-16 Chrysler Corp Brake shoe adjusting and positioning means
US3203512A (en) * 1962-02-13 1965-08-31 Ferodo Sa Hydraulic drum brake

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4842104A (en) * 1983-12-09 1989-06-27 Lucas Industries Public Limited Company Internal shoe drum brake
US4754853A (en) * 1986-06-20 1988-07-05 Shimano Industrial Company Limited Caliper brake for a bicycle
US5261510A (en) * 1992-08-24 1993-11-16 Eaton Corporation Brake spring support pin with spring cam
US6732840B2 (en) * 2001-06-08 2004-05-11 Nisshinbo Industries Inc. Brake cable connecting apparatus for a drum brake device

Also Published As

Publication number Publication date
GB1228343A (it) 1971-04-15
DE1903397A1 (de) 1969-09-04
FR1562953A (it) 1969-04-11
SE340018B (it) 1971-11-01
ES362915A1 (es) 1970-11-16

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