Abstract:
A brake apparatus for use on a hub shaft ( 11 ) supporting a hub ( 2 ) of a bicycle has a brake ring ( 13 ), and a coupling device for coupling the brake ring and the hub to rotatable together. The coupling device includes outer splines ( 13 a) formed on the brake ring ( 13 ) and inner splines ( 2 d) formed in the hub ( 2 ) to allow relative axial movement between the brake ring ( 13 ) and hub ( 2 ) while preventing relative rotation therebetween. The brake apparatus includes brake shoes ( 6 ) disposed inside the brake ring ( 13 ) to be movable into contact with the brake ring ( 13 ). A restrictor is provided far restricting axial movement of the brake shoes ( 6 ) relative to the brake ring ( 13 ). The restrictor includes stoppers ( 27 a) projecting radially outwardly from peripheral positions of an annular shoe presser spring ( 27 ) fitted circumferentially of the brake shoes ( 6 ), and grooves ( 13 b) formed in an inner peripheral wall of the brake ring ( 13 ). The brake apparatus further includes a brake controller ( 7 ) for varying a radial distance of the brake shoes ( 6 ) from an axis of the hub shaft ( 11 ).

Description:
BACKGROUND OF THE INVENTION 
     FIELD OF THE INVENTION 
     This invention relates to a brake apparatus for a bicycle including a main brake body having a braking device and a brake controller, in which the brake controller is operable to switch the braking device between a braking position and a release position. 
     DESCRIPTION OF THE RELATED ART 
     As shown in FIG. 14, a conventional brake apparatus for a bicycle includes a brake ring  13  engaged with an outer periphery at one end of a hub  2 , so that the brake ring  13  forms a part of the hub  2 . Brake shoes  6  acting as a braking device and other components of a main brake body  100  are assembled to the hub  2  in a separate process from assembly of the brake ring  13 . FIG. 15 shows another conventional brake apparatus in which a brake ring  13  is formed integral with a hub  2 . With a main brake body  100  assembled to the hub  2 , the brake apparatus, brake ring and hub may be carried together as a unit. 
     With the former, it is necessary to assemble the brake ring  13  and main brake body  100  to the hub  2  in separate steps. This assembly operation tends to be of poor efficiency with displacements of the respective components occurring at a time of adjustment. 
     In the latter case, the three components of the bicycle are handled as a unit which is heavy. Another disadvantage of this construction is that the end of the hub where the brake apparatus and brake ring are attached is bulky, and particularly large in diameter. It is difficult to handle the bulky construction packed for transportation. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a brake apparatus easy to assemble and adjust, and easy to transport and handle. 
     In order to fulfill the above object, the present invention is characterized by the following three features: 
     1) A braking device forming the brake ring is provided as a separate component from the bicycle hub. 
     2) A coupling device is provided to connect the brake ring to the hub to be rotatable together. 
     3) A restrictor is provided to interconnect the brake ring and the main brake body into an integral unit to be inseparable from each other. 
     The feature 1) allows the hub to be packed and transported separately from the brake ting. The coupling device of feature 2) is provided to facilitate connection of the brake ring to the hub. In a preferred embodiment of the invention, the coupling device includes outer splines formed on the brake ring and inner splines formed in the hub. In the preferred embodiment, the restrictor of feature 3) includes an annular shoe presser spring fitted circumferentially of the brake shoes, and grooves formed in an inner peripheral wall of the brake ring for receiving the presser spring. The brake apparatus has the brake ring and main brake body connected together through engagement between the presser spring and one of the grooves. This construction reduces the possibility of adjustment errors such as a displacement between each brake component and brake ring occurring when the brake apparatus is assembled to the hub, and realizes improved assembling efficiency. 
     The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of preferred embodiments of the invention, as illustrated in the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The drawings show a brake apparatus for a bicycle according to the present invention, in which: 
     FIG. 1 is a front view of a hub having a brake apparatus for a bicycle according to the present invention, 
     FIG. 2 is a side view of the brake apparatus, 
     FIG. 3 is a view, partly in section, of the brake apparatus as assembled, 
     FIG. 4 is a perspective view of the brake apparatus separated from the hub, 
     FIG. 5 is a view, partly in section, of the brake apparatus, 
     FIG. 6 is a view, partly in section, of a coupling portion of the hub, 
     FIG. 7 is a sectional view of a roller assembly of the brake apparatus in an OFF position (second position), 
     FIG. 8 is a sectional view of the roller assembly of the brake apparatus in a non-use position (third position), 
     FIG. 9 is a side view of a roller case of the brake apparatus, 
     FIG. 10 is a sectional view of the roller case, 
     FIG. 11 is a side view showing return springs, 
     FIG. 12 is a side view of an ornamental cap, 
     FIG. 13 is a sectional view of the ornamental cap, 
     FIG. 14 is a view, partly in section of a hub having a brake apparatus according to the prior art, and 
     FIG. 15 is a view, partly in section of another example of hub and brake apparatus according to the prior art. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     As shown in FIG. 1, a bicycle hub  2  includes a left cover  2 a having a spoke connecting flange  1 , an inner element  2 b having a spoke connecting flange  3  and a ratchet mechanism  5  for interlocking a drive gear  4  and the inner element  2 b, and a pipe portion  2 c interconnecting the left cover  2 a and inner element  2 b. 
     As shown in FIG. 3, the left cover  2 a has a brake apparatus assembled thereto and including brake shoes  6  and a brake controller  7 . The hub  2  is supported by a hub shaft  11  through balls  8  and ball pressers  9 . The brake apparatus is supported by the hub shaft  11  through a bush  10 . 
     The hub shaft  11  has mounting nuts  12  screwed to opposite ends thereof for securing the brake apparatus and hub  2  to bicycle frames  101  connected to the hub shaft  11 . The above components constitute a brake and hub assembly of a bicycle. 
     As shown in FIG. 3, the brake apparatus includes a main brake body  100  having the brake shoes  6 , brake controller  7  and other components, and a brake ring  13  coupled to the hub  2 . A basic brake operation is based on a mechanism in which the main brake body  100  applies a frictional braking force to the brake ring  13 , thereby to brake the hub  2 . The construction and working of this apparatus will be described in detail hereunder. 
     The brake ring  13  is in the form of a braking body which is a separate component from the left cover  2 a As shown in FIGS. 4 and 5, the brake ring  13  has splines  13 a formed on an outer peripheral surface at one end thereof. These splines  13 a are fitted in a coupling portion of the left cover  2 a defining splines  2 d as shown in FIGS. 4 and 6. The brake ring  13  is fixed to the hub shaft  11  by a pair of lock nuts  14  mounted on opposite end regions of the hub shaft  11 . The brake ring  13  is interlocked to the left cover  2 a through the splines  13 a and  2 d to be rotatable therewith. 
     As shown in FIGS. 3 and 7, the main brake body  100  includes a plurality of brake shoes  6  and rollers  15  arranged in the circumferential direction of the brake ring  13  and supported by a brake frame  17  through a roller case  16 , and a rotary cam  18  mounted inwardly of the roller case  16  to be rotatable about an axis of rotation of the hub  2  to operate the brake shoes  6 . The rotary cam  18  is rotatable by the brake controller  7  to switch the main brake body  100  between a braking position and a release position. For consistency of terminology used in this specification, the term “first position P 1 ” corresponds to a position of the brake controller  7  to apply the braking force, and “second position P 2 ” corresponds to a position not to apply the braking force. In addition to the first and second positions, the main brake body  100  has a third position P 3  which will be described later. 
     As shown in FIGS. 2 and 3, the brake frame  17  has one end thereof supported by the hub shaft  11  through the bush  10 . A waterproof cap  19  and an ornamental cap  20 amare attached to this end of the brake frame  17 . The other end of the brake frame  17  is supported by a chain stay  102  of the bicycle frame  101  through a clamp band  21 . Thus, the brake frame  17  is in a fixed position relative to the bicycle frame  101  despite a reaction resulting from a braking operation. As shown in FIG. 7, the roller case  16  accommodates all the rollers  15 . The roller case  16  has a fixed pin  22  extending through and contacting the brake frame  17 . The roller case  16  has a range of strokes determined by a circumferential dimension of a bore for receiving the fixed pin  22 . The fixed pin  22  serves to limit circumferential movement of the roller case  16  to the above range of strokes relative to the brake frame  17 . With the above construction, the rollers  15  are supported to be immovable circumferentially of the brake ring  13  during a braking operation. The circumferentially immovable rollers  15  push the brake shoes  6  radially outwardly toward the brake ring  13 . 
     The brake controller  7  extends through the brake frame  17  and rigidly interlocked to the rotary cam  18 , with one end of the brake controller  7  engaged with the rotary cam  18 . The other end of the brake controller  7  projects outwardly from the caps  19  and  20 . As shown in FIG. 2, a cable coupler  23  is attached to the end of the brake controller  7  projecting from the caps  19  and  20 , and a brake cable  24  is connected to the coupler  24 . By a force applied through the brake cable  23 , the brake controller  7  is pivotable about the axis of rotation of the hub  2 . 
     As shown in FIG. 2, when the brake cable  24  is pulled, the resulting tension switches the brake controller  7  to the braking position ON (first position P 1 ). When the brake cable  24  is relaxed, the brake controller  7  is switched to the OFF position (second position P 2 ) shown in FIG. 2, under the force of a return spring  25  acting on the cable coupler  23 . 
     When the brake controller  7  is switched from the second position P 2  to the first position P 1 , the rotary cam  18  is rotated relative to the rollers  15 . As shown in FIG. 7, the rotary cam  18  has brake applying cam portions  18 a formed peripherally thereof which push the rollers  15  radially outwardly of the roller case  16 . The rollers  15  pushed out apply a pressing force to the brake shoes  6 , whereby the brake shoes  6  are pressed on an inner peripheral wall of the brake ring  13  to brake the latter. 
     When the broke  brake controller  7  is switched from the first position P 1  to the second position P 2 , the rotary cam  18  rotates to the position shown in FIG.  7 . The rollers  15  rest in broke  brake canceling recesses  18 b of the rotary cam  18  (that is, the rollers  15  are retracted into the roller ease  16 ) as a result of the rotation of the rotary cam  18 , under a biasing force of the roller ease  16  produced by a return spring  26  acting on the fixed pin  22 , and by returning action of an annular shoe presser spring  27  extending eircumferentially  circumferentially of and contacting all the brake shoes  6 . This cancels the braking action of the brake shoes  6  applied to the brake ring  13 . 
     As shown in FIG. 8, the brake controller  7  lies in a non-use position opposed to the first and second positions P 1  and P 2  under the force of the return spring  25  when the brake cable  24  is not connected or when the brake cable  24  is connected but adjustment is not made yet. This non-use position is called the third position P 3  in this specification. As shown in FIGS. 3 and 11, the roller ease  16  is biased in a fixed direction by the return spring  26  acting on the fixed pin  22 . 
     As shown in FIG. 3, the bush  10  has an inward end  10 c, and a stopper  10 b projecting from the other end thereof. The inward end  10 a is press fit into the brake frame  17 , whereby the bush  10  is assembled securely. 
     The stopper  10 b formed on the outward end of the bush  10  serves to hold the ornamental cap  20  in place. When the ornamental cap  20  is assembled to the bush  10 , the ornamental cap  20  is elastically deformed to override the stopper  10 b before fitting in place. As shown in FIGS. 12 and 13, the ornamental cap  20  has a plurality of lugs  20 a for contacting the stopper  10 b. Thus, the ornamental cap  20  is not easily separable from the bush  10 . The waterproof cap  19  is mounted on the end of the bush  10  press fit into the brake frame  17 , and is sandwiched between the bush  10  and brake frame  17 . The return spring  25  is fitted on the bush  10  between the two caps  19  and  20 . The brake controller  7  extends through the brake frame  17  and is securely assembled to the brake frame  17  along with the caps  19  and  20 , bush  10  and return spring  25 . 
     As shown in FIG. 11, the return spring  26  is engaged with the waterproof cap  19  and fixed pin  22 , so that the fixed pin  22  is not movable out of the waterproof cap  19  toward the brake frame  17 . With the fixed pin  22  not movable out of the waterproof cap  19 , the roller case  16  is assembled to the brake frame  17  along with a case stopper  16 a and waterproof cap  19 . 
     As shown in FIGS. 9 and 10, the roller case  16  includes a first stopper  16 a projecting from an inner end thereof for acting on the rotary cam  18 , and second stoppers  16 b projecting from an outer end thereof for acting on the brake shoes  6 . The first stopper  16 a of the roller case  16  assembled to the brake frame  17  contacts an end of the rotary cam  18 , so that the rotary cam  18  is not movable out of the roller case  16  toward the hub  2 . The second stoppers  16 b of the roller case  16  contact ends of the brake shoes  6  to prevent the brake shoes  6  from becoming displaced from the rollers  15  toward the hub  2 . 
     By the contacting action of the first and second stoppers  16 a and  16 b, the brake shoes  6 , roller case  16  and rotary cam  18  remain assembled to the brake frame  17 . 
     According to the above construction, all the components of the main brake body  100 , such as the brake shoes  6  and brake controller  7  remain assembled together even when the brake apparatus is detached from the hub  2 . 
     As shown in FIGS. 7 and 8, the shoe presser spring  27  includes stoppers  27 a for acting on the brake shoes  6 . As shown in FIG. 3, the brake ring  13  has grease holding grooves  13 b formed in the inner peripheral wall thereof. When the brake controller  7  is shifted to the third position P 3  as shown in FIG. 8, the rotary cam  18  moves to the position shown in FIG. 8 with the movement of brake controller  7  from the second position P 2  to the third position P 3 . In this position, ends of the brake applying cam portions  18 a of the rotary cam  18  opposite the ends thereof used in applying the braking force contact the rollers  15  to press the brake shoes  6  on the brake ring  13 . By this pressing action, the stoppers  27 a of the shoe presser spring  27  enter one of the grease holding grooves  13 b of the brake ring  13  to engage the brake ring  13 . As a result, the brake shoes  6  are securely engaged with the brake ring  13 . The viscosity of grease present in the groove  13 b also promotes adhesion to the brake ring  13  of the brake shoes  6 , which allows the brake shoes  6  to support the brake ring  13 . 
     Thus, the shoe presser spring  27  acts as an engaging device for allowing the brake shoes  6  to securely support the brake ring  13  when the brake controller  7  is in the first position P 1  or the third position P 3 . 
     With the above construction, as shown in FIGS. 4 and 5, the brake ring  13  and main brake body  100  remain assembled together even when the brake apparatus is detached from the hub  2 . The main brake body  100  and brake ring  13  constituting the brake apparatus do not separate from each other, so that the brake apparatus may be assembled to the hub  2  in a single operation. 
     The foregoing embodiment may be modified with respect to the coupling device and braking device. In the foregoing embodiment, the coupling device is in the form of splines  13 a and  2 d for coupling the brake ring  13  and hub  2  to be rotatable together. The coupling device may employ other structures such as screws or caulking. The braking device may comprise a brake band and a cam as replacement for the brake shoes  6  and rollers  15 , respectively.