Abstract:
A bicycle brake shoe assembly including multiple brake pads of different braking compounds replaceably inserted sequentially into a truncated pad holder. The pads have an overlap at one end and an under-lap at the other end such that upon assembly within the holder an overlap portion is mated over an under-lap portion. The pads are captured and retained in place in the truncated holder by a removable end cap. The overlap/under-lap pad mating cooperates with the pad holder and end cap to prevent pad pull out because of wheel rim movement forces on the pads. The brake shoe assembly has a transverse curvature substantially in conformance with the radius of curvature of the bicycle wheel rim, thereby improving pad contact with the wheel rim.

Description:
BACKGROUND  
       [0001]     The background of the invention will be discussed in two parts:  
         [0002]     1. Field of the Invention  
         [0003]     This invention relates to bicycle brake assemblies, and more particularly to an assembly having a brake pad holder with interchangeably brake pads of different braking characteristics, the holder and brake pads having configurations resisting pad compression and pop-out due to wheel rim movement pressure on the pads.  
         [0004]     2. Description of the Related Art  
         [0005]     Bicycles commonly have braking assemblies that grip the bicycle wheel rim in response to operator manipulation of brake levers. Such brake assemblies are generally mounted to the bicycle frame and include brake shoes that are movably mounted on caliper assemblies that bridge the rim. The brake shoes have a brake pad of friction material for abutting and frictionally engaging the rim for slowing or stopping of the bicycle. The majority of such brake pads are of a single material composition and have some form of design in the engaging surface, similar to the tread design of tires, to promote friction for a particular breaking condition, or for braking in general to stop the bicycle. In some prior art brake pads the composition is of such a friction material that cause the pads to squeal or chatter upon application, and in virtually all instances provide uneven wear of the brake pads at the point of engagement resulting in uneven application of force to the rim. Brake shoes having such pads have been generally rectangular in configuration with the fastening stud at the mid-point thereof  
         [0006]     U.S. Pat. No. 5,555,958 issued to Richard C. Everett on 17 Sep. 1996, and U.S. Pat. No. 5,896,955 issued to Richard C. Everett on 27 Apr. 1999, show and describe bicycle brake pads having a partitioned unitary pad with at least two pads formed of dissimilar material, with the pad partitions configured for simultaneous engagement with the bicycle rim. Such brake pads are formed of different combinations of multi-rubber of elastomers instead of a single material composition to thus improve braking characteristics, such as wet or dry braking and/or to stop squealing and grabbing, with the same pad.  
         [0007]     U.S. Pat. No. 6,244,396 issued to Lumpkin on 12 Jun. 2001 discloses an elongate brake pad holder having a plurality of removable pad segments axially positioned in the holder. A stay maintains the pads in a fixed position within the holder. No provision is made therein to provide restriction of pad compression and pad pull out, and thus pad stability, due to the wheel rim movement pressure on the pads:  
         [0008]     Such devices are illustrative of the many and varied arrangements whereby attempts have been made to improve the braking of bicycles. However, the related art brake pads, and even brake assemblies, remain limited in braking characteristic variation and flexibility. For the foregoing reasons there is a need for a brake pad assembly having replaceable pads with dissimilar braking characteristics providing for braking variation and flexibility under different riding conditions with adequate provision for pad stability in the pad holder.  
         [0009]     It is thus an aspect of the present invention to provide a new and improved bicycle braking assembly having interchangeable brake pads providing for braking variation and flexibility under different riding conditions.  
         [0010]     It is another aspect of the invention to provide an improved bicycle brake assembly having a re-useable brake shoe, or holder, for receiving brake pads composed of different braking compounds that can be interchanged and rearranged within the shoe to provide variation in braking characteristics of the assembly.  
         [0011]     It is also an aspect of the present invention to provide an bicycle brake assembly having replaceable pads of different braking compounds with adjacent pads having alternate overlapping and under-lapping ends such that when assembled within the holder an overlapping end is mated over an under-lapping end to deter pull out of the pads due to wheel rim movement pressure.  
         [0012]     It is a further aspect of the invention to provide a unique bicycle brake holder having replaceable brake pads with dissimilar braking characteristics including a removable end cap providing increased resistance to pad compression, bulging, and pull out due to wheel rim pressure on the pads.  
         [0013]     Other aspects, features and advantages of the invention will become apparent from a reading of the specification, when taken in conjunction with the drawings, in which like reference numerals refer to like elements in the several views.  
       SUMMARY  
       [0014]     The present invention is directed to a bicycle brake shoe assembly that satisfies the need for a brake pad assembly with replaceable pads of different compounds having different braking characteristics providing for braking variation and flexibility under different riding conditions with adequate provision for pad stability in the pad holder. The assembly includes a plurality of replaceable pads inserted sequentially into an elongated truncated pad holder, the pads formed of different braking compounds to provide different braking characteristics to the bicycle. The pads may be replaced and/or rearranged within the holder. They are captured and retained in place by locking means such as an end cap configured for mating engagement with the truncated holder. The brake pads are configured to coordinate with the pad holder and locking means to provide for increased resistance to pad compression, bulging, and/or brake pad pull out of the holder due to wheel rim movement pressure on the pads. The brake pads have an overlap at one end and an under-lap at the other end such that upon assembly in the holder the overlap portion of a pad is mated over the under-lap portion of the adjacent pad. The assembly design characteristics provide pad pop-out resistance to pressure from wheel rim movement. The brake pad holder has a longitudinal curvature that is substantially in conformance with the radius of curvature of the bicycle wheel rim, thereby improving pad contact with the wheel rim. 
     
    
     DRAWINGS  
       [0015]      FIG. 1  is a perspective view of a brake shoe assembly having brake pads of different configuration and braking compounds embodying features of the present invention;  
         [0016]      FIG. 2  is an exploded perspective view of a brake shoe assembly of  FIG. 1 ;  
         [0017]      FIG. 3  is a perspective view of the brake shoe holder of  FIG. 1  without the brake pads assembled in the holder;  
         [0018]      FIG. 4  is a perspective view showing the configuration of the brake pads embodying features of the present invention;  
         [0019]      FIG. 5  is a top perspective view of the brake shoe assembly of  FIG. 1 ;  
         [0020]      FIG. 6  is across-sectional view of the brake shoe assembly of  FIG. 5  along the line  6 - 6  of  FIG. 5 ;  
         [0021]      FIG. 7  is a side view of the brake shoe assembly of  FIG. 1 ;  
         [0022]      FIG. 8  is a bottom view of the brake shoe assembly of  FIG. 6 ; and  
         [0023]      FIG. 9  is a top view of the brake shoe assembly of  FIG. 6 .  
     
    
     DESCRIPTION  
       [0024]     Referring now to the drawings, and particularly to  FIGS. 1 and 2 , there is shown brake shoe assembly, generally designated  10 , embodying features of the invention. The assembly  10  includes a fastening means, such as a threaded stud member  11 , secured to a brake pad support member, such as the backbone, or brake pad holder  12 . Holder  12  is truncated with an open end configured to matingly accept complementary closure means such as end cap  16 , thus allowing for insertion into holder  12  of brake pads  13 - 15  which are then captured in place by end cap  16  and secured by locking pin  20 . End cap  16  and locking pin  20  not only serve to capture and secure pads  13 - 15  within holder  16 , but, as will be further explained below, are designed and positioned, in cooperation with brake pad design, to prevent brake pad pop-out due to wheel rim movement pressure on the pads. Holder  12  can be of forged and machined aluminum whereas end cap  16  can be die cast aluminum. Other materials and methods of manufacture could be used without departing from the spirit and scope of the invention.  
         [0025]      FIG. 2  illustrates in exploded view the brake shoe assembly  10  of  FIG. 1 . After the brake pads  13 - 15  are sequentially inserted into holder  12  as will hereinafter be explained, end cap  16  is mated to holder  12  as variously shown in the figures. As shown in  FIGS. 2, 3  and  6 , holder  12  has a protrusion  12   a  defined by an undercut groove  17  that extends around the perimeter of the holder  12  except for the truncated open end thereof Likewise, end cap  16  has a protrusion  16   a  defined by undercut groove  19 , and is designed for mating with the truncated open end of holder  12 . As best shown in  FIG. 2 , the truncated end of holder  12  is formed with a first side  18  recessed inwardly in cutout manner in the holder  12 . Although not shown, the other side of the truncated end is formed with an identical inwardly recessed side  18 . This provides that the outside dimension of holder  12 , at the recessed sides  18 , is less than the inside dimensions of groove  19  of end cap  16 . Thus, when end cap  16  is mated to holder  12 , groove  19  slides around the inwardly recessed sides  18  whereby, as shown in  FIG. 3 , the outside dimensions of holder  12  become the same as the outside dimensions of end cap  16 .  
         [0026]     Further, recessed sides  18  have step cuts  18   a , and protrusions  12   a  and  16   a  have cut away portions above holes  21   b ,  21   c  and  21   a ,  21   d , respectively. Thus, in mating of end cap  16  to holder  12 , protrusion  16   a  overlaps step cuts  18  and cut away portions of protrusions  16   a  and  12   a  mate together. Likewise, the inwardly cut-away portions of protrusion  12   a  and the outwardly cut-way portions of protrusion  16   a  mate flush and even. Mated in this complementary manner, as shown in  FIG. 3 , protrusions  16   a  and  12   a  provide a continuous aligned protrusion, and associated undercut, completely around the perimeter of the combination of holder  12  and end cap  16 . This continuous protrusion and associated undercut groove of holder  12  and end cap  16  provides for brake pads  13 - 15  to be captured and aligned as will be hereinafter explained. The recessed sides  18  have holes  21   b  and  21   c  and end cap  16  has holes  21   a  and  21   d  that match up when end cap  16  mates with holder  12  such that pin  20  can be inserted therethrough to secure end cap  16  to holder  12 . Thus, locking pin  20  is inserted, in sequence, into end cap  16  aperture  21   a , through matching aperture  21   b  in holder  12 , through brake pad recess  22  (see  FIG. 4 ) and then ultimately through apertures  21   c  and  21   d  of holder  12  and end cap  16  respectively.  
         [0027]     In  FIGS. 2, 4  and  6 , the brake pads  13 - 15  are described embodying features of the invention,  FIG. 6  being a cross-sectional view taken along the lines  6 - 6  of  FIG. 5 . Pads  13  and  14  have braking portion surfaces  13   a ,  14   a , and substantially identical overlap ends  13   b ,  14   b , under-lap ends  13   c ,  14   c , and undercut indentations  13   d ,  14   d  that define pad bottom protrusions  13   e ,  14   e , respectively. Brake pad  15  is shown configured as a special pad such as a wiper pad, and as such has surface  15   a , overlap  15   b , undercut indentation  15   d  defining pad bottom protrusion  15   e , and a shortened protrusion  15   c  mating with end cap protrusion  16   a . Since protrusion  15   c  is not mated to another pad, it can be as shown, but need not be, of a different configuration. To properly perform its function as a wiper pad, pad  15  would be the last pad inserted and thus the lead pad as the rim turns into the brake assembly. Otherwise, the pads could be inserted in any order desired and pad  15  could be of the same configuration as pads  13  and  14 . In this case protrusion  15   c , indentation  15   d  and bottom protrusion  15   e  would have the same configuration as that of pads  13  and  14  and it would still mate satisfactorily with end cap  16 . The pads each has recesses  22  configured for coacting engagement with pin  20  as previously described.  
         [0028]     As shown in  FIG. 1  and indicated in  FIG. 2 , pads  13 - 15  are sequentially loaded into holder  12  with overlap  13   b  of pad  13  placed first into holder  12  such that, as shown in  FIG. 6 , pad undercut indentations  13   d  are slid along the holder protrusions  12   a . Pad  13  is inserted along holder protrusions  12   a  until brought against the end of the cavity of holder  12 . Brake pads  14  and  15  are then similarly loaded in close proximity within holder  12 , overlapping ends fitting fully over under-lapping ends, as for instance under-lap end  13   c  mating with overlap end  14   b . The pads  13 - 15  are thus closely mated by means of the overlap ends of a pad mating with the under-lap end of an adjacent pad. The end-to-end overlap and under-lap in the holder  12  and end cap  16  provide that protrusions and indentations thereof extend completely around the pads.  
         [0029]     After the pads  13 - 15  are loaded they are captured securely in place by the attachment of complementary end cap  16 , and insertion of locking pin  20 . Thus the pad sequence and assembly braking characteristics may be changed by merely removing locking pin  20  and end cap  16 , removing existing pads, and inserting pads of different braking compounds and/or rearranging the sequence of the pads. Any of the pads can be a specially designed pad, such as a wiper pad, configured to provide desired characteristics to the assembly. It is generally desirable that the rim-engaging surface of each pad be co-planar with that of the other pads so that the required effect of each pad is accomplished with substantially simultaneous engagement with the rim by each brake pad surface. However, this not a requirement as a pad could initially extend higher than other pads but of a compound designed to “mush” to another level so as to provide an additional characteristic such as wider breaking or cleaning area.  
         [0030]     The rim direction of moving contact is directly into brake pad  15 , thus pad  15  and end cap  16  directly bear the contact forces of the turning rim surface that tends to compress, displace, and pull out the pads from the brake assembly  10 . This problem is eliminated by the combination of the features of the invention as shown and described. That is, the interaction of protrusions  12   a ,  16   a  of holder  12  and end cap  16  with the indentations  13   d ,  14   d ,  15   d  of the brake pads, the over lapping of the pads, and locking end cap  16 , cooperate to stop the pads from being pulled out of the brake assembly  10 .  
         [0031]     Further, although not indicated in  FIG. 6 , a portion of the brake pad could be of a compound designed to provide brake pad break up and pull out resistance due to wheel rim moving forces whereas the remainder of the brake pad would manifest desirable braking characteristics. For instance, the brake pad portion indicated by numerals  15   c ,  15   d  and  15   e  could be of a compound designed to provide brake pad break up and/or pull out resistance whereas the exterior brake pad portion is formed of a compound that provides a desired breaking characteristic.  
         [0032]      FIG. 6  is a perspective view,  FIG. 7  is a side view,  FIG. 8  is a bottom view and  FIG. 9  is a top view of the brake pad in accordance with features of the invention. As indicated in  FIGS. 7-9 , for better contact of the brake pads with the bicycle wheel rim, holder  12  has a longitudinal curvature substantially in conformance with the radius of curvature of the bicycle wheel rim. The assembly configuration provides that the pads are in sequential alignment in the curved holder  12  and in alignment relative to the direction of travel of the rim of the bicycle. Also, as indicated in  FIG. 5 , the top of holder  12  has exposed molded functional structure ribs  30 , in a corrugated manner that provides additional rigidity and strength to holder  12 .  
         [0033]     Brake shoe assembly  10  is shown with holder  12  having three brake pads therein, although more or fewer pads could be utilized by varying the lengths and/or configurations of the pads and/or changing the length of holder  12 . In general, each pad is comprised of selected compounds that provide various desired braking characteristics and individually cured and formed such that they can be sequentially inserted into and removed from pad holder  12  as described. Further, even though the pads are generally individually molded of different compounds, it is to be understood that a pad can be unitarily molded to include two or more of the pads shown or can be formed of different compounds to enhance break up or pull out as described. Multi-rubber or elastomeric compounds having different combinations of multi-rubber or elastomers, not a particular combination, can be utilized to provide the desired braking characteristics. Additionally, the pads, or portions of the pads, may have different colors as a means of color-coding to distinguish certain characteristics of the pads. Also, different pad surface patterns can be used to identify certain braking characteristics. For instance, although not shown, brake pad surfaces  13   a  and  14   a  could have selected designs for identifying different characteristics. Additionally, although the means for complementary closing of the truncated pad holder is shown and described as an end cap with a locking pin, other complementary closure means such as a snap on end cap having interlocking means for mating with the holder can be employed within the spirit and scope of the invention.  
         [0034]     In accordance with the above, there has been shown and described a bicycle brake pad assembly having replaceable pads with different braking characteristics providing for braking variation and flexibility under different riding conditions with adequate provision for pad stability in the pad holder. Individual brake pads have different braking characteristics are easily inserted into and removed from a truncated pad holder whereby the pads are easily replaced and rearranged within the holder. The pads have configuration and the holder has an end cap that provides for increased resistance to pad compression, bulging, and/or brake pad pull out of the holder due to wheel rim movement pressure on the pads.  
         [0035]     The appended claims should not be limited to the description of the invention contained herein, it to be understood that various other adaptations and modifications may be made within the spirit and scope of the claims.