Brake system for wheeled skates

The present invention is a brake system for wheeled skates, and in particular in line skates. The brake system consists of at least one brake disk, but preferably two sets of interleaving disks. The first set of disks are keyed to a wheel's shaft, and the second set of disks are keyed to the inner hub of the wheel. The first set of disks cannot rotate around the shaft which is fixedly attached to the frame of the skate. The second set of disks rotate with the wheel. Both sets of disks are free to move axially. To brake, a skater shifts his weight onto the outside of his feet, which causes both the first set and second set of disks to move towards the inside of the skate and compress together. The frictional force between the rotating second set of disks and the nonrotating first set of disks causes the second set of disks to decrease in rotational speed. The slowing of the second set of disks which are keyed to the wheel causes the wheel to commensurately slow down and, if the pressure is maintained, come to a stop.

FIELD OF THE INVENTION 
The present invention relates to brake systems for wheeled skates, and in 
particular, in line wheeled skates. 
BACKGROUND OF THE INVENTION 
In line skates have become very popular in the last ten years or so, almost 
completely replacing traditional roller skates as the preferred form of 
wheeled skates. These skates are enjoyed by a broad cross section of the 
population for general recreational use, and by specialized other groups 
for such activities as trick and acrobatic skating, and hockey and other 
athletic activities. 
One problem encountered by virtually all users of in line skates is the 
lack of an effective brake system. While prior art brake systems exist for 
in line skates and roller skates, such systems tend to be simplistic and 
have major limitations. For example, the brake system typically provided 
on in line skates consists of a hard rubber pad attached to the back of 
the skate frame. Through the flexing of the skater's ankle, the pad is 
brought into contact with the ground and a crude braking is effectuated. 
While the more athletic and talented skaters seem to effectively brake in 
most circumstances by bringing the brake pad into contact with the ground, 
less experienced skaters may find the brake pad workable only at slow 
speeds. 
Another method of braking involves dragging one skate, turned 90 degrees to 
the direction of travel, behind the skate bearing the skater's weight and 
pointed in the direction of travel. Disastrous falls can occur however 
when the skate being dragged is not properly positioned and the wheels 
roll the skate away from the desired path at an unexpected angle. 
A further method of braking sometimes used is to skate in a zig-zag or 
slalom pattern, with a braking action occurring in each turn. 
Additionally, some after market systems have employed a cable with one end 
attached to a brake device on the skate, and the other end coupled to a 
hand-held actuator. Upon engaging the actuator the cable forces a brake 
pad to contact a skate wheel or the ground. 
In light of the shortcomings of prior art brake systems for in line skates, 
it is an object of the present invention to provide an improved, more 
reliable and safer brake system for in line skates. 
SUMMARY OF THE INVENTION 
The novel brake system of the present invention allows a skater to 
implement a controlled braking action through a slight variation of the 
normal skating motion. The brake system comprises at least one disk, but 
preferably a series of disks, which are assembled between the wheel 
bearings in the hub of at least one wheel per skate. Approximately half of 
the disks are keyed to and rotatable with the wheel hub or a sleeve 
inserted into the wheel hub. The remaining disks are interleaved with 
these rotating disks and positioned around an inner hub which slides over 
a shaft. The shaft, the inner hub, and the disks positioned around the 
inner hub cannot rotate. Both the rotating disks which are keyed to the 
wheel hub, and the nonrotating disks which are slidably coupled to the 
inner hub, can move axially to a slight degree. The rotating disks can 
move axially through the key slot in the wheel hub and the nonrotating 
disks can move axially along the inner hub. 
During a normal skating motion, a skater pushes his or her skates out and 
back at approximately a 45 degree angle. This pushing off places a force 
on the inner portion of the skate wheels, and consequently forces the 
wheels and braking disks to slide axially towards the outside of the 
skate. While there may be some contact among the disks during this skating 
motion, the disks do not compress against one another, and a braking 
action is therefore not produced. Similarly, when the skater is coasting 
with the wheels of each skate pointed in the direction of travel, the 
brake disks will move back and forth axially to some degree depending on 
the vagaries of the skating surface and the positioning of the skater's 
feet and ankles. However, once again, the brake disks do not compress 
against one another and a braking action does not occur. 
To achieve a braking action utilizing the present invention, a skater bows 
out his ankles by rolling onto the outside portion of his feet. This 
causes force to be transferred from the bottom or inside portion of the 
wheels to the outside portion of the wheels, and consequently causes the 
wheels and brake disks to move axially towards the inside portion of the 
skate. Since the skater maintains his feet in this position throughout the 
braking process, the brake disks not only travel axially towards the 
inside portion of the skate, but the disks compress together and remain 
compressed together. The compression of the brake disks causes the 
rotating disks attached to the wheel hub to lose speed because of the 
frictional drag imparted on the rotating disks by contacting the 
nonrotating disks. As the rotating disks lose speed, the hub and wheel 
commensurately lose speed, and the wheels of the skate eventually come to 
a stop.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
As illustrated in FIG. 1, a wheel system of an in line skate consists of a 
shaft 12, a wheel 13, bearings 11, bearing seats 33, and a skate frame 14. 
FIG. 5 shows such a wheel system on an in line skate 40. The wheel itself 
contains a hub 18 and a hub sleeve 19. The bearings 11 rotatably mount the 
wheel 13 on shaft 12. The hub sleeve 19 may be integral with the hub 18, 
or it may be a separate sleeve which slides into the hub 18. The system 
may also have an inner hub 35 concentrically coupled to shaft 12. The 
wheel 13 is attached to the skate frame 14 by placing the shaft 12 through 
an opening of the wheel hub 18, placing shaft 12 into receiving slots 16 
of the frame 14, and fixedly attaching the shaft 12 to the frame 14 via 
fastener 17. The foregoing is the basic wheel system of an in line skate. 
The brake system of the present invention is identified by the number 10 in 
FIG. 1, and can be incorporated into the wheel system of an in line skate. 
Alternatively, the brake system of the present invention could be 
incorporated into a traditional four-wheeled roller skate. The brake 
system 10 preferably comprises two sets of disks 21 and 22. Disk 21 is 
illustrated in FIG. 3 and disk 22 is illustrated in FIG. 4. A first set of 
disks 21 is keyed to hub sleeve 19 via retaining tabs 28 on each disk 21. 
The keying of disks 21 to hub sleeve 19 causes the disks 21 to rotate with 
the wheel 13. Tabs 28 are slidably coupled to wheel 13 through key slots 
31 as illustrated in FIG. 2, which is a sectional view taken along line 
a--a of FIG. 1. The outermost disk 21a is bounded by wheel hub sleeve 
shoulder 25. The disks 21, while they are keyed to the hub sleeve 19 and 
rotate therewith, also can move axially in slots 31 during skating. Such 
movement is critical to the brake system 10 of the present invention as 
will be explained infra. 
A second set of brake disks 22 are slidably coupled to inner hub 35, which 
as stated supra concentrically surrounds shaft 12. As shown in FIG. 4, 
openings in centers of the annular disks 22 are slots in the shape of a 
double D, and as illustrated in FIG. 2, the cross section of the middle of 
the shaft 12 shows that it is also double D-shaped to fit through the 
double D-shaped openings in the disks 22. Because of this non-circular 
coupling and the fixed attachment of shaft 12 to skate frame 14, disks 22 
cannot rotate with the wheel 13 as do the disks 21. However, the disks 22, 
like disks 21, can move axially along inner hub 35. The innermost disk 22a 
is bounded by the inner hub shoulder 26. The axial movement of disks 22 is 
limited by inner hub shoulder 26. Like the axial movement of disks 21 
through slot 31, the axial movement of disks 22 along inner hub 35 plays a 
vital role in the brake system 10. 
The brake system 10 functions as follows. When a skater is moving in the 
normal forward direction, he is either coasting by placing his feet 
parallel to the direction of travel, or he is actively skating by 
alternatively pushing out and back using the inside portion of the wheels 
13. During coasting, there is sufficient play in the wheels 13 and disks 
21 and 22 so that disks 21 freely rotate with wheel 13 and no braking 
action occurs. During the active skating motion, the skater pushes off and 
out on the inside portion of wheels 13. This causes the entire wheel 
assembly, i.e. the wheel 13, bearing seats 33, wheel hub 19, wheel hub 
sleeve shoulder 25 and disks 21 and 22 to move axially towards the outside 
of the skate, as designated by arrow A in FIG. 1. This axial motion is 
permitted by a sliding fit between the bearing seats 33 and the inner hub 
35. The axial movement of wheel hub sleeve shoulder 25 increases the axial 
space between it and inner hub shoulder 26, thereby allowing the 
uninhibited rotation of disks 21. Consequently, coasting and a normal 
skating motion disengage the brakes. 
To brake, the skater must transfer his weight in such a manner so that his 
weight is put on the outside portion of the wheels 13. The skater 
preferably does this by first pointing his skates parallel to the 
direction of travel, and then bending his ankles outward so that his 
weight "rolls onto" the outside portion of his skates. Alternatively, a 
skater can engage the brake system 10 by pointing his toes slightly inward 
in a snow plow position. The transfer of the skater's weight to the 
outside portion of the wheels 13 causes the entire wheel assembly, i.e. 
the wheel 13, bearing seats 33, wheel hub 19, wheel hub sleeve shoulder 
25, and disks 21 and 22 to move axially towards the inner hub shoulder 26 
which is stationary. The axial movement of wheel hub sleeve shoulder 25 
towards the inner hub shoulder 26 narrows the gap between wheel hub sleeve 
shoulder 25 and inner hub shoulder 26, and compresses disks 21 and 22 up 
against inner hub shoulder 26. The disks 21 and 22 remain in this 
compressed position as long as the skater maintains his weight on the 
outside portion of the skates. When the disks 21 and 22 are compressed in 
this manner, the rotational speed of disks 21 decreases because of the 
frictional drag between the disks 21 and the nonrotating disks 22. The 
decrease in rotational speed of disks 21 causes a commensurate loss of 
rotational speed of the wheels 13 since disks 21 and wheel 13 are 
connected via tabs 28 and key slots 31. If the skater maintains the 
outside pressure on the wheels 13, the disks 21 eventually cease rotating, 
thereby stopping wheel 13 from rotating, thereby stopping the skater. 
For efficient braking, the brake system 10 should be installed on at least 
two wheels of a skate. Most in line skates have four wheels per skate, and 
placing the brake system 10 on the middle two wheels is recommended. 
Furthermore, the selection of suitable materials for the disks, and/or the 
positioning of materials of a higher/lower friction coefficient between 
the two sets of disks, allows the range and magnitude of braking force to 
be controlled. The inventors have discovered that manufacturing the disks 
out of readily available spring hardened steel results in effective 
braking. 
While the preferred embodiment of the invention has been described as 
employing a plurality of disks 21 keyed to the hub sleeve 19 to rotate 
with the wheel 13 and a plurality of disks 22 slidably coupled to shaft 
19, it will be appreciated that the braking could be achieved with only 
one disk 21 and one disk 22. Other mechanisms could also be used to brake 
the wheel in response to the narrowing of the axial space between the 
shoulders 25 and 26. 
It will further be appreciated by those skilled in the art and it is 
contemplated that variations to the embodiments illustrated and described 
herein may be made without departing from the spirit and scope of the 
present invention. Accordingly, it is intended that the foregoing 
description is illustrative only, and the true spirit and scope of the 
invention will be determined by the appended claims.