O USOO5390771A

United States Patent (19) 11 Patent Number: 5,390,771

Hinkens et al. (45) Date of Patent: Feb. 21, 1995

54) EEPER BRAKE ASSEMBLY FOREIGN PATENT DOCUMENTS

75 Inventors: George H. Hinkens, Fox Point; Curt 1274412 5/1992 United Kingdom ................ 188/344
H. Blaszczyk, Sturtevant, both of Primary Examiner-Robert J. Oberleitner
Wis. Assistant Examiner-Chris Schwartz
73) Assignee: Hayes Industrial Brake, Inc., Attorney, Agent, or Firm-Foley & Lardner
Mequon, Wis. 57 ABSTRACT
(21) Appl. No.: 51,474 A caliper brake assembly for a bicycle having a fork, a
wheel having an axle mounted in said fork, and a brake
22 Filed: Apr. 22, 1993 disk mounted on the wheel, the assembly including a
51) Int. Cl. ......................... B62L 1/10, B60T 11/14 caliper housing mounted on the fork in a position to
52 U.S. C. ................................. 188/344; 188/24.12, bridge the brake disk, the housing including an arm
188/724 connected to the axle and a blind-bore in the housing
58) Field of Search .................... 188/724, 72.5, 72.6, having a closed end and an open end, a piston mounted
188/196R, 71.7, 71.9, 344, 24.12, 24.22; in the bore on each side of the disk, each piston includ
280/75, 76 ing a brake pad, a master cylinder assembly connected
to the bore, the caliper housing including passages con
56) References Cited necting the open end of the blind bore to the closed end
U.S. PATENT DOCUMENTS of the blind bore, and a lever assembly mounted on the
2,414,753 1/1947 Majneri........................... 188/140 R icvcl for actuating the master cylinder assembly to
bicycle
188/71.7 pressurize the bore and move the pistons into engage
3,297,115
3,935,930 1/1967
2/1976 Waloen et al.
Kine ............. ae 188/344 ment with the disk to brake the rotary motion of the
5,082,093 1/1992 Sule .......... ... 1884.22 wheel.
5,193,833 3/1993 Reisinger ........................... 188/72.4
5,259,483 11/1993 Pelfrey ............................... 188/72.4 13 Claims, 3 Drawing Sheets
U.S. Patent Feb. 21, 1995 Sheet 1 of 3 5,390,771
U.S. Patent Feb. 21, 1995 Sheet 2 of 3 5,390,771

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U.S. Patent Feb. 21, 1995 Sheet 3 of 3 5,390,771

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5,390,771
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providing a resilient tape between the clamp and the
HYDRAULC CALIPER BRAKE ASSEMBLY FOR fork which compensates for different sized forks.
A BICYCLE One of the primary advantages of the double piston
type caliper brake is the ability to adjust for brake pad
FIELD OF THE INVENTION wear on the caliper. This has been achieved by provid
The present invention relates to a disk brake assembly ing an adjustable cap in the open end of the bore on the
for a bicycle and more specifically to a cable applied casting for changing the pad gap.
caliper type hydraulic double piston disk brake assem In accordance with another aspect of the invention
bly for a bicycle. the caliper can be adjusted to center the brake disk
10 between the pistons in the caliper and thereby eliminate
BACKGROUND OF THE INVENTION drag. This has been achieved by mounting the caliper
Caliper type disk brakes, hydraulic or mechanical, on a screw on the fork clamp or to a bracket perma
generally provided on bicycles include a caliper having nently attached to the fork. The screw can be turned to
a fixed brake pad on one side of the brake disk and a center the disk between the pad assemblies.
movable brake pad mounted on a piston on the other
5 Another feature of the invention is the provision of a
side of the brake disk. The brake is actuated by a hand brake which has a closed hydraulic system so that the
bicycle can be turned upside down without losing hy
operated lever mounted on the handlebar of the bicycle draulic fluid.
which is connected to the caliper by a cable. Compensa Other principal features and advantages of the inven
tion for wear of the brake pads can be adjusted for on 20 tion will become apparent to those skilled in the art
the lever and on the caliper body to vary the stroke of upon review of the following drawings, the detailed
operation of the cable. description and the appended claims.
One type of hydraulic brake on the market is con
nected to the fork by two screws that are located above BRIEF DESCRIPTION OF THE DRAWINGS
the axle. There is no part of the brake that goes downto 25 FIG. 1 is a side elevation view of the double piston
the axle. To use this brake requires buying a special fork hydraulic caliper disk brake shown mounted on the fork
that accepts this brake. Another type of brake on the of a bicycle;
market can be adapted to most forks. This brake has an FIG. 2 is a perspective view of the caliper according
arm that goes down to the axle. However, you must to the invention;
disconnect the cable and a fork hose clamp to remove 30 FIG. 3 is a cross section view of a portion of the
the wheel. The brake stays with the wheel when the caliper showing the brake disk aligned with the pistons
wheel is removed. This is cumbersome and takes a lot of in the bore of the caliper;
time, and special tools are required to remove the cali FIG. 4 is an enlarged cross section view of the cap
per. shown mounted in the blind bore;
The two types of disk brakes presently on the market 35 FIG. 5 is a view of the hand operated lever shown
have one fixed pad and one movable pad. To allow the connected to the operating lever for the master cylin
fixed pad to move away from the disk, the brake in one der; and
case and the disk in the other are mounted on pins FIG. 6 is a top view of the clamp assembly shown
which matingly engage corresponding bores. The pins mounted on the caliper housing.
will cause minimal drag when a good design is well invention Before explaining at least one embodiment of the
maintained. However if the design is poor or any rust or in detail it is to be understood that the inven
dirt get between the pins and bores, the drag will in tion is not limited in its application to the details of
crease. Even a minimal drag will irritate and impair the set construction and the arrangement of the components
power of the rider. forth in the following description or illustrated in the
45 drawings. The invention is capable of other embodi
SUMMARY OF THE PRESENT INVENTION ments or being practiced or carried out in various ways.
The present invention relates to a caliper type hy Also, it is to be understood that the phraseology and
terminology employed herein is for the purpose of de
draulic brake for a bicycle and more particularly to a scription and should not be regarded as limiting.
double opposed piston hydraulic caliper disk brake. 50
One of the primary features of the present invention is DETAILED DESCRIPTION OF THE
the provision of a one piece casting having a bore with PREFERRED EMBODIMENTS
a master cylinder housing and a bleed valve housing The brake caliper 10 according to the present inven
formed as an integral part of the brake casting. The one tion, as shown in the drawings, is mounted on the fork
piece casting lowers cost and weight. 55 12 of a bicycle in a position to engage the outer periph
Wheel removal has been simplified by providing an ery of a brake disk 14 mounted on the wheel hub 16.
arm on the casting which includes a slot to matingly The
engage the wheel axle. The casting is pivotally mounted clampcaliper 10 is mounted on the fork 12 by means of a
assembly 18 which is adjustable for mounting on
on the bicycle fork thus making it possible to swing the different size forks. The clamp assembly 18 as shown in
brake away from the axle during disassembly thereby FIG. 6 includes a clamp 20 having an opening 22 which
allowing for the removal of the wheel and brake disk generally conforms to the shape of the fork 12. The
from the bicycle. The direction of the angle of the slot clamp 20 can be adapted to different size forks by wrap
in the arm of the casting also holds the casting on the ping a resilient tape 23, either rubber or plastic, and
axle during braking if a rider forgets to tighten the axle clamping the clamp 20 over the tape. The clamp 20 is
quick release. 65 pivotally connected to a housing 24 on the top of caliper
A further feature of the double cylinder caliper brake 10 by a threaded pin 26 having a bolt head 28 at one end
is the provision of a variable size fork clamp which can and a hex nut 30 on the other end. The lower end of the
be adjusted to fit most bicycle forks. This is achieved by caliper 10 is connected to the axle 32 of the bicycle by
 5,390,771
3. 4.
means of a “J” shaped arm 34 having a slot 36 which 126 at the end of bore 118. A threaded plug 120 is
matingly engages the axle 32 of the wheel. It should be screwed into the threaded bore 118 to block the port
noted that the caliper 10 will tend to pivot about the pin 126. Air in the passages 84, 86, 94, 96 and 98 can be
26 in the direction of rotation of the wheel when the released by backing the plug 120 off the port 126.
brake is applied, forcing the slot 36 in the “J” shaped Means are provided for centering the disk 14 between
arm 34 against the axle 32. This arrangement also allows the brake pads 56 and 58 in the slot 46 in the caliper
for a quick and easy removal of the wheel from the housing 38. Such means as shown in FIG. 6, is in the
bicycle frame. This is accomplished by pivoting the form of the threaded pin 26 mounted in clamp assembly
caliper 10 including the “J” shaped arm 34 away from 18. In this regard, the threaded pin 26 is threadedly
the axle 32 of the wheel which allows the wheel to be 10 received in a threaded opening 124 provided in the
easily removed. housing 24 at the top of the caliper housing 38. The
The caliper 10 generally includes a cast aluminum adjustment pin 26 is frictionally free to rotate in the
cylindrical housing 38, as shown in FIGS. 2 and 3, openings 122 in the fork clamp 20. The caliper pads 56
having a blind bore 40. A master cylinder housing 42 and 58 are centered on the disk 14 by rotating the pin 26
and an air bleed cylinder housing 44 are formed as an 15 in the threaded opening 124 in the housing 24. The
integral part of the cylindrical housing 38. A slot 46 is screw 26 remains fixed in the openings 122 in the fork
provided in the caliper housing 38 in a spaced relation clamp 20 and as the caliper housing is moved axially
to the closed end of bore 40. with respect to the threaded opening 124 of housing 24.
Piston assemblies 48 and 50 are positioned in the blind Although only one screw is described herein to adjust
bore 40 on each side of the slot 46. Each piston assembly 20 the position of the caliper housing, it is within the con
includes a piston 52 and 54, respectively, and a brake templation of the invention to use one screw to close the
pad 56 and 58, respectively. The pistons are sealed in clamp on the fork and a second screw to adjust the
the bore 40 by means of seal rings 60 and 62 seated in housing.
grooves 64 and 66, respectively, provided in the bore 40 Thus, it should be apparent that there has been pro
around the outer perimeter of pistons 52 and 54. Wipers 25 vided in accordance with the present invention a hy
68 and 70 are provided in grooves 72 and 74 in the bore draulic caliper brake assembly for a bicycle that fully
40 to wipe the outside surfaces of the pistons 52 and 54. satisfies the objectives and advantages set forth above.
The open end of bore 40 is closed by means of a cap Although the invention has been described in conjunc
76 which is positioned in the open end of the bore 40 tion with specific embodiments thereof, it is evident that
and locked therein by means of a retaining ring 78. The 30 many alternatives, modifications and variations will be
cap 76 is sealed in the bore 40 by means of a seal ring 80 apparent to those skilled in the art. Accordingly, it is
seated in groove 82 provided in the open end of bore 40. intended to embrace all such alternatives, modifications
The cap 76 is initially seated on the retaining ring 78 to and variations that fall within the spirit and broad scope
provide a space 84 between piston 54 and cap 76. This of the appended claims.
space can be reduced as described hereinafter by turn 35 The embodiments of the invention in which an exclu
ing the threaded section 88 on cap 76 inwardly on the sive property or privilege is claimed are defined as
threaded section 90 in bore 40. The inward movement follows:
of cap 76 is limited by a shoulder 92 at the end of 1. A caliper brake assembly in combination with a
threaded section 90 in bore 40. The space 84 is con bicycle having a frame, a fork mounted on the frame, a
nected to the space 86 between piston 52 and the inner 40 wheel supported on the fork and a brake disk mounted
end of bore 40 by passages 94 and 96. on the wheel, said assembly comprising:
The master cylinder housing 42 as shown in FIG. 5 a brake assembly mounted on the fork, said assembly
includes a blind bore 98 which is connected to the space including a unitary housing having a blind bore and
84 between the cap 76 and the piston 54 by means of a a slot in said blind bore intermediate the ends of
passage 100. A piston 102 is positioned in the blind bore 45 said blind bore, the brake disk being aligned with
98 which is actuated by a lever 104 pivotally mounted said slot, a pair of piston assemblies mounted in said
on a bolt 106 on the arm 34. The piston 102 includes a blind bore for movement into engagement with
groove 101 having an O-ring 103 positioned therein to opposite sides of said disk, a passage in said housing
seal the piston in the housing. A return spring 105 is interconnecting the opposite ends of said bore,
provided in the bore 98 to bias the piston to the open 50 a master cylinder in said caliper housing operatively
position. The lever 104 includes a post 108 which is connected to pressurize said blind bore for move
positioned to engage the end of piston 102. The lever ment of said piston assemblies into engagement
104 is connected to a hand lever 110 mounted on the with said disk, and
handlebar 112 by a cable 114 with post 108 abutting the means mounted on the bicycle to actuate said master
end of piston 102. A stop 116 is formed on the “J” 55 cylinder to move said piston assemblies into en
shaped arm 34 to limit the rotation of lever 104 so that gagement with said disk.
piston 102 will not drop out of the housing 42. A boot 2. The combination according to claim 1 including
115 may be provided to protect the piston from contam passage means in said housing interconnecting said mas
ination. ter cylinder with said piston assemblies to equalize the
The piston 102 is pushed up to pressurize the fluid in 60 pressure on the piston assemblies, and
the spaces 84 and 86 in bore 40 by squeezing the hand a bleed housing formed in said caliper housing for
lever 110 to pivot the lever 104 upward against the releasing air from said passage means.
piston 102. Fluid will enter the bore 40 through passage 3. The combination according to claim 2 including a
100 pressurizing the fluid in passages 94 and 96 to simul cap mounted on one end of said housing in a spaced
taneously pressurize the spaces 84 and 86 moving both 65 relation to one of said pistons, said cap being adjustable
piston assemblies 48 and 50 into engagement with disk to maintain said gap.
14. The bleed housing 44 includes a threaded bore 118 4. A caliper brake assembly in combination with a
which is connected to the end of passage 96 by a port bicycle fork having an axle and a wheel mounted on the
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5,390,771
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fork and a brake disk mounted on the wheel, said assem a cap mounted on the open end of said first blind bore
bly comprising: in a spaced relation to one of said piston assemblies,
a caliper housing pivotally mounted on the fork in a passage means in said housing connecting the space
position to bridge the brake disk, said housing hav between said cap and said one of said piston assem
ing an arm removably connected to the axle and a blies and the space between the end of the first
first blind bore in said housing having a closed end blind bore and the other of said piston assemblies
and an open end, and a master cylinder assembly mounted in said
a piston assembly mounted in said first blind bore on second blind bore and being operatively connected
each side of said disk, each piston assembly includ to said space between the cap and said one of said
ing a brake pad, 10 piston assemblies for pressurizing said piston as
a second blind bore in said housing connected to said semblies into engagement with said disk.
first blind bore, a master cylinder assembly 9. The caliper brake according to claim 8 wherein
mounted in said second blind bore, each of said piston assemblies includes a piston and a
a passage in said caliper housing connecting said open brake pad, and said cap is adjustable to compensate for
end of said first blind bore to said closed end of said 15 wear of said brake pads.
first blind bore, and 10. The caliper brake according to claim 9 wherein
means mounted on the bicycle and connected to said said clamp assembly includes a compressible tape to
master cylinder assembly for pressurizing said first accommodate various size forks.
blind bore to move said brake pads into engage 11. The caliper brake according to claim 10 including
ment with said disk to brake the rotary motion of means for adjusting the position of the housing to center
the wheel. said brake pads with respect to the disk.
5. The brake assembly according to claim 4 including 12. A double piston caliper brake assembly in combi
a cap mounted in the open end of said first blind bore in anation with a bicycle having a fork, an axle on said fork,
wheel mounted on said axle and a brake disk mounted
a spaced relation to one of said pistons, said pressurizing
means being connected to said first blind bore between 5 onasaid wheel axle, said brake assembly comprising:
housing having a blind bore and a slot intermediate
said cap and said piston.
6. The caliper brake assembly according to claim 5 the ends of said bore,
wherein said cap is adjustable to compensate for wear of a universal clamp assembly pivotally mounting the
said brake pads. housing on the fork of the bicycle with the brake
7. The caliper brake assembly according to claim 6 30 disk aligned with said slot,
including a limit stop in said first blind bore to prevent an arm on said housing for releasably connecting the
over travel of said cap to prevent damage to the piston housing to the wheel axle,
assembly and disk due to wear of the brake pads. a piston assembly mounted in said blind bore on each
8. A double piston caliper brake assembly in combina 35 side of said slot for movement into engagement
tion with a bicycle fork having an axle mounted on the with said disk,
fork, a wheel rotatably mounted on said axle and a a cap mounted in the open end of said blind bore in a
brake disk mounted on said wheel, said brake assembly spaced relation to one of said piston assemblies,
comprising: a passage in said housing connecting said space be
a housing having a first blind bore having a slot inter tween said cap and said one of said piston assen
mediate the ends of said bore and a second blind blies and the space between the end of said bore
bore, and the other of said piston assemblies, and
a clamp assembly pivotally mounted on the upper end
a master cylinder assembly connected to the space
of said housing for mounting the housing on the between said cap and said one of said piston assem
blies for pressurizing said piston assemblies into
fork of the bicycle with the brake disk aligned in 45 engagement with said disk.
said slot, 13. The brake according to claim 12 wherein said arm
an arm formed on said housing for securing the lower includes a slot for connecting the arm to the axle of the
end of the housing to the wheel axle, wheel, said arm being located to pivot in a direction
a piston assembly mounted in said first blind bore on counter to the direction of rotation of the wheel
each side of said slot for movement into engage 50 whereby said axle will be seated in said slot.
ment with said disk, :k k is sk

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