Unitary molded skate chassis

A one-piece, plastic molded, roller skate chassis, including foot plate, trucks, and wheel axles. Each truck, which provides for turning in a conventional manner, includes a cylindrical torsional member, inclined at a predetermined angle with respect to the foot plate, and a shank attached at one end to the torsion member and at the opposite end to a cylindrical shaft which receives the axle of the roller skate. The plastic from which the present chassis is molded is tough and durable, and yet sufficiently flexible and resilient to allow turning. Also disclosed is an adjustable two-piece skate chassis in which each mating member is on a one-piece, molded plastic molded construction.

BACKGROUND OF THE INVENTION 
The present invention relates to a roller skate chassis and, more 
particularly, to a unitary, plastic molded chassis which is durable, less 
expensive to manufacture, and whose performance is very comparable to 
chasses of conventional construction. 
The United States has recently witnessed a tremendous surge in the 
popularity of roller skating. Although this activity is still just as 
popular as it probably ever was among children, the recent rise in 
popularity has primarily been among teenagers and young adults. As a 
result, roller skates are currently being used for a wider range of 
purposes, such as dancing and transportation, as well as for the 
traditional purpose of recreation. 
This surge in roller skating popularity has received wide-spread public 
notoriety, and was referred to on the cover of one weekly news magazine as 
"Roller Mania". Naturally, there has been a tremendous increase in roller 
skate sales and in the establishment of skating rinks. Some cities have 
even established special roller skating lanes, adjacent to heavily 
travelled pedestrian sidewalks, for the exclusive use of roller skaters 
and skateboarders who have chosen this alternate mode of transportation. 
In response to this new found popularity, roller figure skating and speed 
skating were, for the first time, competitive events in the Pan American 
games, and it is anticipated that these events will also be part of the 
1980 Olympic games. 
The increased participation in roller skating has been prompted in part by 
the development of polyurethane wheels and improved truck and bearing 
assemblies which have provided new dimensions of speed and manuverability 
to the sport of roller skating. In the past, however, roller skate foot 
plates and truck assemblies were typically constructed from metal by the 
use of casting process. Although these truck assemblies performed 
adequately, they were relatively expensive to manufacture. 
Therefore, paralleling this rise in popularity has been an increasing 
public demand for less expensive roller skating equipment which 
nonetheless is durable and offers the same advantages of speed and 
manuverability as conventional roller skates. 
SUMMARY OF THE PRESENT INVENTION 
The present invention consists of a roller skate foot plate and truck which 
is of a one-piece, plastic molded construction. The unitary plate and 
truck provide a chassis which is relatively inexpensive to manufacture, as 
compared with roller skates of the prior art, and yet is just as durable 
and manuverable. 
The chassis of the present invention is constructed from a tough, durable 
plastic, which is also sufficiently flexible and resilient to provide for 
turning. Because of its unitary construction, the present chassis is 
easier to assemble than previous chasses in that no subassembly of the 
truck to the plate is required. The present invention is also able to take 
advantage of recent improvements in wheels and bearings to yield a roller 
skate which exhibits all of the characteristics of speed and 
manuverability of conventional skates. Furthermore, the lightness of the 
plastic construction of the present chassis provides for a skate which is 
superior to the prior art in terms of these important characteristics. 
The chassis of the present invention consists of a foot plate, two spaced 
wheel trucks suspended beneath the plate and an axle in each truck which 
receives the wheels of the chassis. The axles are made of metal and are 
placed in the mold at the time the present invention is molded so that 
they become and integral part of the unitary construction. The foot plate 
is provided with means for attaching the chassis to the sole of a shoe or 
other foot-receiving component of a complete roller skate. 
The truck of the present invention consists of a torsional member which is 
inclined with respect to the foot plate and supported at each end by 
structural members extending below the foot plate. Attached to the central 
portion of the torsional member is a shank which extends further downward 
and connects it to a cylindrical axle mount. 
The present truck provides for turning in generally the same manner as 
conventional roller skates. As the skater shifts his weight and leans to 
one side during turning, the foot plate tends to rotate about the 
torsional member which in turn causes the wheel axles to converge toward 
one another on that side. This convergence causes the skate to turn in the 
direction the skater has leaned. 
The torsional member can be inclined at various angles relative to the foot 
plate, thereby providing for more or less ease in turning, as desired by 
the individual. However, stops are provided which act in conjunction with 
tabs on the axle mounts to prevent the skater from leaning dangerously too 
far to one side or the other. Furthermore, the torsional member supplies a 
suspension system for the roller skate since it is able to flex in 
response to uneven forces acting through the wheels, axle and shank. In 
this regard, the thickness of the torsional member can be adjusted 
according to the weight of the individual skater. 
An alternate skate truck, which also forms a one-piece chassis with the 
foot plate, consists of only a shank which is attached directly to the 
bottom of the plate and inclined with respect thereto. This truck 
embodiment turns in the same manner as that described except that the 
shank flexes about an imaginary axis of rotation which is perpendicular to 
its longitudinal dimension and which forms a vertical plane with the 
longitudinal axis of the foot plate. 
The present invention also includes a novel adjustable roller skate 
chassis. An adjustable chassis is desirable when a single chassis is being 
manufactured for attachment to various sizes of shoes. Furthermore, on 
some occassions, the plate of the chassis is attached to a larger foot 
plate which is adapted to receive the street shoe of a roller skater, as 
opposed to a skating shoe. Therefore, it is desirable that the chassis of 
such a roller skate be adjustable in order to accommodate various foot 
sizes of individual skaters. 
Two separate plate and truck assemblies of unitary construction are each 
provided with a pair of horizontally extending beams which slidably 
interlock to provide a range of adjustment. The beams of each assembly are 
diagonally arranged with respect to each other such that when mated with 
the beams of the opposing assembly, each individual beam is contiguous 
with the beams of the opposite assembly. 
This diagonal interlocking arrangement prevents horizontal and vertical 
movement of the beams in a direction transverse to the skate's length and 
provides for a rigidly secure chassis. A bolt is inserted through 
apertures in mating beams in order to lock the assembly together and to 
prevent movement in the longitudinal direction. The interface surfaces of 
adjacent beams can also be provided with serations to further discourage 
such longitudinal movement. Finally, in order to provide even further 
security, apertures in each assembly can be provided to receive the ends 
of the beam from the opposing assembly.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
FIG. 1 depicts a complete roller skate 10 consisting of a shoe member 12 
for receiving the foot of the skater, a chassis 14 attached to the bottom 
of the shoe, and wheels 16 attached to the chassis 14. A toe stop 18 
provides means for braking the motion of the roller skate. 
FIG. 2 is a perspective view of the unitary chassis 14 of the present 
invention. In the preferred embodiment, the chassis 14 is molded from a 
tough, strong plastic such as Dupont's "Nylon Super Tough", ST801. The use 
of the plastic provides for an inexpensive, durable roller skate which is 
also light, thereby enhancing its speed and manuverability. The one-piece 
construction of these chassis can be described in detail by reference to 
FIGS. 2, 3 and 4. 
Referring initially to FIG. 2, a planar foot plate 20 is shown which is 
shaped generally like the bottom of a foot except it is symmetrical about 
its longitudinal axis. The plate 20 is narrow in its central portion and 
wider in its forward and rearward portions so as to provide additional 
support for the truck and wheel assemblies, and shoe 12, to be described 
in more detail below, suspended beneath it. Slots 22 are cut out the 
periphery of the plate 20 and located on both sides thereof. The plate 20 
is attached to the sole of the shoe 12 by means of the slots 22 which 
receive threaded screws or rivets (not shown). 
Prominently shown in FIG. 2 are front and rear axle mounts 56a and 56b, 
respectively, which are part of the front and rear trucks. The axle mounts 
56a and 56b receive front and rear axles 58a and 58b, respectively, on 
which wheels 16 are mounted, as shown in FIG. 1. In the preferred 
embodiment, axles 58 are made of metal and loaded into the die before the 
chassis 14 is molded so that they need not be assembled later. 
FIGS. 2 and 3 depict triangular braces 24 and 26 located beneath the toe 
and heel portions, respectively, of the foot plate 20. The front brace 24 
consists of a front rectangular beam 28 and a rear rectangular beam 30 
formed beneath the plate 20 in a V-shaped structure which is strengthened 
by a web 32. Similarly, rear brace 26 consists of front and rear 
rectangular beams 34 and 36, respectively, formed in the shape of a V, and 
a web portion 38. The front beam 28 of the front brace 24 has an aperture 
19 and a larger surface area than other beam members of the braces 24 and 
26 in order to accommodate attachment of the toe stop 18, shown in FIG. 1. 
Referring particularly to FIG. 3, beneath the central portion of the plate 
20 is attached a trapezoidal support section 40 consisting of a forward 
leg 42 and a rear leg 44 joined by means of a horizontal flange 46. As 
with the braces 24 and 26, the framework of this support section 40 is 
reinforced by means of a web 48. 
Suspended beneath the plate 20 and mounted between each brace 24 and 26 and 
the support section 40 are front and rear truck assemblies 50a and 50b, 
respectively, shown best in FIG. 3. Each truck 50 consists of a torsional 
member 42 which is inclined with respect to plate 20, and a shank 54 which 
is attached at one end to the torsional member 42 and at the other other 
end to axle mount 56. As described above, the axle mounts 56 receive axles 
58 on which are mounted the wheels 16. The axles 58 have threaded end 
portions 59 which receive nuts (not shown) to securely hold the wheels 16 
in place. As will be described in connection with FIGS. 5, 6 and 7, the 
trucks 50 work in cooperation with the plate 20 to provide for turning of 
the roller skate in the direction the skater leans. 
Referring again to FIG. 3, the torsional member 52a of the front truck 50a 
is mounted in a struct-like fashion between the base of the beam 30 of the 
front brace 24 and the lower end of the front leg 42 of the support 
section 40. It is disposed midway between and parallel to the longitudinal 
sides of the plate 20. The torsional member 52a and the plate 20 form an 
acute angle .theta.a which opens toward the rear of the chassis 14. 
Attached just rearward of the middle of the torsional member 42a and 
extending downwardly, essentially at a right angle with respect wardly, 
essentially at a right angle with respect thereto, is shank 54a. Attached 
to the lower end of the shank 54a is axle mount 56a consisting of an 
elongate cylindrical shaft lying transverse to the length of the plate 20, 
as shown in FIG. 4, which retains the front axle 58a. 
The rear truck 50b is identical in construction to the front truck 50a; 
however, it is mounted beneath the plate 20 so as to face in the opposite 
direction. That is, the angle .theta.b that rear torsional member 52b 
makes with respect to the plate 20 opens toward the front of the chassis 
14, as shown in FIG. 3. As will be described in more detail below, this 
arrangement of the torsional members with respect to the plate 20 enables 
the skater to turn in the direction in which he leans on the roller skate. 
Furthermore, the ease with which turning is accomplished depends upon the 
acuteness of the above-described angles, which in the preferred embodiment 
are equal. 
As with the front truck, the rear truck 50b is supported at each end by the 
base of the front beam 34 of the rear brace 26 and the lowe end of the leg 
44 of the support section 40. Similarly, the shank 54b is attached to the 
torsional member 52b just forward of its center to form essentially a 
right angle and is attached at its opposite end to the axle mount 56b. As 
shown clearly in FIG. 4, the torsional members 52 in the preferred 
embodiment are cylindrical, although other shapes may be used. 
FIGS. 3 and 4 illustrate that the shank members 54 are rectangular in 
cross-section, with the longer side lying transverse to the plate 20. This 
shape allows the front and rear shanks 54a and 54b to flex forward and 
rearward, respectively, in response to bumps or other irregularities in 
the skating surface. More importantly, the suspension system of the 
chassis of the present invention is enhanced by resiliency of the 
torsional members 52 which serve as excellent shock absorbers since they 
are supported at each end and the shanks 54 attached approximately at 
their centers. In this regard, the thickness of the members 52 can be 
increased or decreased depending upon the weight of the individual skater. 
Referring again to FIGS. 2 and 3, a stop 62 is attached at one end near the 
point of the front brace 24 and extends downwardly toward the axle mount 
56. Similarly, behind front truck 50a another stop 64 is attached at one 
end to leg 42 of the support section 40 and extends forwardly toward axle 
mount 56. In like manner, a pair of stops 66 and 68 are attached to the 
rear leg 44 and rear brace 26 respectively, and angle toward one another 
and the rear axle mount 56b. The free ends of each of these stops 62, 64, 
66, and 68, are spaced above small tabs 60 located approximately midway 
between the wheels on the front and rear surfaces of the axle mounts 56. 
As will be described in more detail below, these tabs, in cooperation with 
stops 62, 64, 66 and 68, limit the sharpness of the turning angle of a 
roller skate having the chassis of the present invention. 
The manner in which the chassis 14 of the present invention enables the 
skate 10 to turn can be best described by reference to FIGS. 5, 6 and 7. 
The trucks 50 of the present invention turn in conventional manner when 
the skater shifts his weight or leans to one side or the other, as shown 
in FIG. 6. For example, if the skater leans to his left, as in FIG. 6, the 
axes 70 of the axles 58, originally in positions 70a and 70b, tend to 
converge toward one another on the left side, as shown in FIG. 5 by axes 
positions 70a' and 70b', thereby allowing the wheels to affect a left 
turn. This convergence of the wheels toward one another on the side of the 
turn is made possible by the opposite inclination of the torsional members 
52 relative to the foot plate 20, and the extent of this convergence 
produces the turning angle of the roller skate. 
The manner in which a roller skate turns can be more easily described if 
one considers the relative movement between an axle 58 and the plate 20, 
as shown in FIG. 7. That is, as a skater leans in one direction or 
another, the plate 20 tends to tilt to that side, as shown in FIG. 6, 
while the axle remains horizontal, parallel to the ground. However, by 
assuming the reverse, that is, that the axle tilts towards the plate which 
remains horizontal, the convergence of the axles toward one another on the 
side of a turn is more easily explained. 
FIG. 7 is a schematic view of the front portion of the chassis 14 of the 
present invention illustrating only portions of the plate 20, the 
torsional member 52a and the ends of the axle 58a relative to the plate 20 
under the above assumption. Thus, prior to turning both the left end 58a' 
and the right end 58a" of the axle 58a are aligned in position 58a, 
perpendicular to the longitudinal dimension of the plate 20 and defining a 
plane parallel to the plane thereof. 
As a skater's weight is shifted to the left, the axle 58a will become 
inclined toward the plate 20; however, the rotation of the axle will be 
about the axis 72a of the torsional member 52a and the displacement of 
each end of the axle will be in a plane, indicated at 74a, at right angles 
to said axis. Therefore, the left end 58a' of the axle is displaced upward 
and rearward from its original left position 58a and the right end 58a" 
correspondingly shifts downward and forward, as shown in FIG. 7. In 
summary, assuming the axle 58a rotates relative to the plate 20 during 
turning, and because the ends of the axle move in the plane defined by 
line 74, there is a total horizontal displacement, indicated by A, as well 
as a total vertical displacement, indicated by B. 
Considering the turn as it actually occurs, with the plate 20 tilting and 
the axle 58 remaining horizontal, the total vertical displacement B, shown 
in FIG. 7, actually takes place in the inclination of the foot plate to 
the left, as shown in FIG. 6. However, the horizontal displacement A, 
results in the counter clockwise displacement of the front axle, indicated 
by its axis 70a in FIG. 5. Thus, the angle .theta.a which opens towards 
the rear of the skate, enables the front axle 58c to rotate in the 
appropriate manner so as to affect a left turn when the skater's wheight 
is shifted to the left. In a like manner, .theta.b, which angle opens 
toward the front of the skate, enables the rear axle 58b to be displaced 
clockwise, as indicated by the axis 70b in FIG. 5, when skater's weight is 
shifted to the left so as to effect a left turn. 
It should also be noted that the degree of the turning angle of the roller 
skate is directly proportional to the acuteness of the angles .theta.. 
That is, as that angle becomes less actue, less inclination of the plate 
20 is required to produce the same horizontal displacement A and the same 
amount of turning shown in FIG. 5. 
The function of the stops 62, 64, 66, and 68 shown in FIGS. 2 and 3, in 
limiting the turning angle of the roller skate, can now be explained. As 
the skater leans to one side or the other in a turn, contact by the free 
end of the stop on the upper surface of the tabs 60 will prevent the 
skater from leaning dangerously too far and possibly falling. However, 
because of the flexibility of the stops, if contact should be made with 
the tabs 60, a limited turn can still be accomplished without causing the 
skater to fall or otherwise injure himself. 
An alternate truck embodiment is shown in FIG. 8 which illustrates the rear 
portion of a chassis 14. It consists solely of a shank member 76 which is 
attached at one end at the plate 20 and at the other end to the axle mount 
56. The cross-section of the shank 76 can take on a variety of shapes; 
however, it is preferred that the narrow dimension of the cross-section be 
transverse to the longitudinal dimension of the plate 20 so as to allow 
the shank 76 to flex in the transverse direction. 
The shank 76 turns generally in the same manner as the trucks 50, described 
above in connection with FIGS. 5, 6 and 7. As the plate 20 is inclined 
during turning, it tends to cause the shank 76 to flex about an axis which 
is perpendicular to its longitudinal axis 77, shown in FIG. 8. The precise 
vertical position of this axis of rotation is difficult to determine; 
however, the shank would flex approximately about the axis indicated at 
79. This axis of rotation 79 is analogous to torsional member 52 and is 
inclined relative to plate 20 in the same manner. Thus, as described above 
in connection with the preferred truck embodiment 50, as the plate 20 
tilts duriing turning, the relative rotation of the shank 76 about axis 79 
will cause the axes 70 on the side of the turn to converge as shown in 
FIG. 5. 
FIG. 9 is an exploded perspective view of a novel adjustable roller skate 
chassis 76. Adjustability in the chassis of the present invention is 
provided by two pair of interlocking beams, 80, 82 and 84, 86 which are 
slidably engaged with one another. The plate and truck assemblies from 
which these beams extend are identical to that described above except that 
the central narrow portion of the plate 20, the flange 46 and the web 48 
are removed leaving two separate front and rear plate portions 20a and 20b 
from which are suspended the two truck assemblies 50a and 50b, 
respectively. 
Extending rearwardly from the front leg 42 are two horizontal beams 80 and 
82 which are spaced diagonally from one another. The upper beam 80 is 
essentially rectangular in cross-section and larger than the square 
cross-section of the lower beam 82. Similarly, extending forwardly from 
the rear leg 42 are two horizontal beams 84 and 86 which are also spaced 
diagonally with respect to each other and of an identical construction as 
that of beams 80 and 82. The two pair of diagonal beams are constructed so 
that when mated, as shown in FIG. 10, the upper beams 80 and 84 are 
adjacent one another and directly above these lower beams 82 and 86, which 
are also adjacent to one another. The mating surfaces of upper beams 80 
and 84 are also provided with serations 88 which tend to prevent 
longitudinal movement of the two upper beams 80 and 84 relative to one 
another. 
When the desired length for the chassis 78 is obtained, the two plate 
members 20a and 20b can be fixed relative to one another by insertion of a 
bolt 90 through slot 92 in the upper beam 80 and a hole 94 in the adjacent 
upper beam 84. The bolt 90 can then be secured in place by means of a nut 
96, as shown in FIG. 10. 
To provide additional security to the chassis 78, apertures 98 are provided 
in the legs 42 and 44 to receive the ends of the lower beams 82 and 86. 
The apertures 98 will prevent the lower beams 82 and 86, and also the 
upper beams 80 and 84, from movement in the horizontal and vertical 
direction. Similarly, apertures 99 are cut out of legs 42 and 44 (although 
only one such aperture 99 is shown in FIG. 9) and receive the ends of 
upper beams 80 and 84. 
Preferably, each pair of beams will form a part of the unitary plastic 
molded construction of the respective individual chassis members which 
together make up the complete adjustable chassis 78. Thus, the advantages 
of this type of construction are combined with the advantages of an 
adjustable roller skate chassis to yield a roller skate which is superior 
to the prior art. 
The adjustability feature of the present invention can be used in 
combination with either truck embodiment 50 or 76 disclosed herein, or any 
other truck. As merely one example of the preferred truck 50, torsional 
member 52 has a circular diameter of 3/8 inch, length of 13/4inch and 
makes an angle .theta. of 15.degree. with respect to the plate 20. A 
chassis having a truck of these dimensions will display adequate 
characteristics of turning for an average adult, however, these dimensions 
can be varied depending upon the weight and shoe size of the individual 
skater. Furthermore, even within each weight class, other examples of 
truck dimensions will be readily apparent to one skilled in the art which 
will allow the principles and advantages of the present invention to be 
fully practiced. 
In summary, the roller skate chassis of the present invention is 
inexpensive, unitary, and of a one-piece plastic molded construction, 
which can also be modified to be adjustable, and which is comparable to 
chassis of the prior art in terms of speed and manuverability.