US 3885804 A
A roller skate having a sole plate, a boot and two large canted equal sized wheels mounted on axles extending outwardly from the sole plate. The canted wheels contact the ground directly beneath the center line of the sole plate. The wheels are dished with their concave sides facing toward the sole plate and a portion of the sole plate extends into the wheel concavities to permit the sole plate to be positioned very close to the ground.
Description (OCR text may contain errors)
United States Patent [191 Cudmore 14 1 May 27, 1975 ROLLER SKATE  Inventor: Patrick J. Cudmore, Cambridge,
 Assignee: Wane-Rider, Incorporated,
22 Filed: June 13, 1973 211 Appl. No.: 369,759
 US. Cl 280/11.2; 280/11.23  Int. Cl. A63c 17/14  Field of Search 280/ll.l R, 11.25, 11.23,
 References Cited UNITED STATES PATENTS 2,706,119 4/1955 Uphoff 280/1 1.3 3,387,852 6/1968 Sarro 280/1 1.2
FOREIGN PATENTS OR APPLICATIONS 215,734 2/1909 Germany 280/11.23
425,889 10/1947 Italy 2230/1123 Primary ExaminerPhilip Goodman Attorney, Agent, or Firm-Thompson, Birch, Gauthier & Samuels I 5 ABSTRACT A roller skate having a sole plate, a boot and two large canted equal sized wheels mounted on axles extending outwardly from the sole plate. The canted wheels contact the ground directly beneath the center line of the sole plate. The wheels are dished with their concave sides facing toward the sole plate and a portion of the sole plate extends into the wheel concavities to permit the sole plate to be positioned very close to the ground.
12 Claims, 4 Drawing Figures ROLLER SKATE BACKGROUND OF THIS INVENTION In the past. there have been many attempts to Construct a roller skate which has a pair of large wheels mounted outboard of the sole plate. The advantages of such an arrangement over the conventional four wheeled roller skate include (a) sharper turns can be made; (b) higher speeds can be attained; (c) fewer shocks are transmitted to the skaters legs; and (d) skating can be done on surfaces which are not perfectly smooth.
However, one problem which has not previously been solved is how to construct such a roller skate which does not produce undue strain on and discomfort to the skater's ankle. Also, another problem is how to construct such a roller skate which is stable and which does not have a pronounced tendency to tip to either side. It is the object of this invention to solve these problems.
SUMMARY OF THE INVENTION The roller skate of this invention has several unusual features which cooperate to produce superior skating characteristics while providing comfort to the skaters feet and legs. The skate has a sole plate and an attached boot or other foot engaging means to grip the skaters foot. Two axles extend to the outside of the sole plate and are angled downwardly. Two equal sized wheels are mounted on the axles and are canted so that their tires roll on the ground vertically beneath the center line of the sole plate. This ensures that there is no strain applied to the skaters ankle under normal conditions.
Furthermore, the sole plate is positioned as close to the ground as possible. In the preferred embodiment, this is accomplished by dishing the wheels with their concave sides facing inwardly toward the sole plate. The sole plate is mounted so that it extends into the concave front wheel and, optionally, into the rear wheel as well. This permits the sole plate to be located in an extremely low position.
Thus, when the skaters ankles are straight, there is virtually no lateral strain applied to them. Also, when the skater bends his ankles during skating turns, because the sole plate is so low the torque forces applied to the ankles are likewise low.
DESCRIPTION OF THE DRAWINGS FIG. 1 is a top plan view of the left roller skate of this invention showing the sole plate and wheels, the boot being removed for purposes of clarity.
FIG. 2 is a sectional view taken along line 2-2 of FIG. 3, the lower portion of the boot being shown in full.
FIG. 3 is a side elevational view taken from the inner side of the roller skate. The skaters foot or shoe is shown in dotted.
FIG. 4 is a sectional view taken along line 44 of FIG. 3, the rear portion of the boot being shown in full.
DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, FIG. 3 shows the left roller skate which is a mirror image of the right roller skate. For that reason, only the shown left skate need be described in this application.
The roller skate has a sole plate 10 which is substantially horizontal. This means that it may be precisely horizontal, or it may be somewhat raised in the heel portion as shown in FIG. 3, or it may be slightly angled otherwise to comply with other design criteria.
The sole plate, as viewed from above in FIG. 1, has a shape suitable to support the skaters left shoe or foot (shown in dotted). In the shown preferred embodiment, it will be assumed that the skater is wearing sneakers. The sole plate 10 has a toe portion 12, a wide ball portion 14, a narrow arch portion 16, and a heel portion 18. Attached to the front tip of the sole plate toe portion is a rubber toe stop 20 which is useful as in aid in stopping, starting, and executing abrupt maneuvers. An imaginary sole plate center line 22 runs front to rear or longitudinally. In order to lighten the sole plate without sacrificing its rigidity, perforations 24 are cut in a regular pattern throughout the sole plate.
Sole plate 10 has an outer margin 26 which runs along the outer edge of the sole plate. Outer margin 26 has considerable size and strength and serves three functions. First, it strengthens the sole plate itself against bending or twisting. Second, it provides an outer wall to restrain at least the outside of the ball of the shoe or boot. Third, and most important, it forms the foundation in which the two axles (to be described later) are rigidly mounted. In the shown preferred embodiment, the outer margin 26 extends upwardly in the sole plate ball portion 14 and extends downwardly in the sole plate heel portion 18. This can be appreciated by comparing ball portion margin 28 in FIG. 2 with heel portion margin 30 in FIG. 4.
In order to skate with the roller skates, the skater must first affix the skates to his shoes or feet. This can be accomplished in many conventional ways, such as with straps running around the skaters shoes or with skate-held boots which the skater wears on his feet. In the preferred embodiment, semiboots 32 are employed to grip the skaters sneakers. FIG. 3 shows a front gripper 34 which is applied across the ball of the foot and also shows a rear gripper 36 which is applied around the ankle. Front gripper 34 is fixed to the sole plate to lock the ball of the foot in a single longitudinal position relative to the front wheel axle, as shown in FIG. 1. In contrast, rear gripper 36 is provided with cam means 38 which cooperates with the sole plate to adjustably position rear gripper 36 along the sole plate to accommodate various shoe sizes.
The semi-boot 32 has conventional closure means in the manner of ski boot clasps 40. The shown clasps are adjustable so as to regulate snugness. It will be understood that the shown semi-boot is simply one form of foot engaging means which is attached to the sole plate and which is adapted to grip and securely maintain the skaters foot or shoe against the upper surface of the sole plate.
As previously mentioned, a pair of identical axles are mounted on the sole plate. Front axle 42 is mounted in the ball portion 28 of outer margin 26, and rear axle 44 is mounted in the heel portion 30 of outer margin 26. Referring to FIG. 2, it will be seen that each axle has a shaft 46 which is firmly anchored at its upper and inner end in outer margin 26. The shaft is shaped at its lower and outer end to carry a ball bearing assembly which will be described subsequently. Both axles are mounted so that they extend outwardly and downwardly at an angle of approximately 30 to 33 relative 3 to the horizontal, and both axles are parallel to each other.
The roller skate is provided with two equal-sized wheels. Front wheel 48 and rear wheel 50 are preferably approximately 8 inches in diameter and have a hub 51 into which a ball bearing assembly 52 is press-fit. The wheels are mounted on axles 42 and 44 by means of a retaining bolt 54, as shown in FIG. 2, so that the wheels can rotate freely in either direction on their ball bearings. However, it should be understood that a less expensive roller skate construction utilizing this invention could substitute another type of bearing arrangement and still achieve satisfactory results.
The identical wheels are dished, as can best be seen in FIG. 2, each with its concave side facing inwardly. Each wheel has a peripheral rim 56 which is preferably offset at an angle to the plane of the wheel periphery. Tires 58 (made of hard rubber or other similar material) are mounted on rims 56 and, because of the canted offset rims, roll squarely on the ground.
It should be understood that the provision of dished wheels is highly desirable to the efficient functioning of this invention, although not absolutely mandatory. Dished wheels permit the wheels to be mounted in a more upright position which significantly reduces the amount of torque applied to the ball bearing assemblies. High torque causes friction and binding whereas low torque causes smooth running of the bearings. Dished wheels also produce a roller skate which has a narrower front profile. This is a desirable feature because it reduces the likelihood of catching the wheels on obstacles to the side. Finally, dished wheels, which are more upright, roll more easily and with less friction than severely canted wheels which roll on their sides.
Referring to FIG. 2, it will be seen that tire i 58 contacts the ground directly under the center line of sole plate 10. This is shown by vertical line VV. Also, line AA has been drawn through the plane of tire 58 and line BB has been drawn from tire 58 tangent to the outermost portion of wheel 48.
A design limitation of the roller skate of this invention relates to the fact that as the skater turns, his inside skate leans in the direction of the turn. As the turn becomes sharper, the inside skate leans further. At some lean angle, the skate can lean no further because the retaining bolt will contact the ground and the tire will rise up off of the ground causing all traction to be lost. The skate will then slide out from under the skater and the skater will fall. Ideally, the skater should be able to lean his skates as much as he desires, but in skates having outboard wheels this is not possible. It will be seen in FIG. 2 that the preferred embodiment can lean through an angle 'yor approximately 36 before all traction is lost. Actually, effective traction is lost at a slightly smaller angle. Obviously, the more upright the wheel is (i.e. the greater angle 'y is), the more the skate can be leaned into a turn. This permits increasingly sharp turns to betaken.
However, as the wheel is mounted in an increasingly upright position to maximize the permissible angle of lean, another design criterion comes into play. This design criterion is the desire to locate the sole plate as close to the ground as possible to reduce lateral strain on the skaters ankle which occurs when the ankle is being bent or being straightened. Lateral ankle strain is caused by the torque moment which is the product of the horizontal force component times the vertical distance between the applied forceand the pivot. Obviously, if the vertical distance is reduced by shortening the distance between the sole plate and the ground, the torque produced by any given horizontal force component will be proportionately reduced. Therefore, if the sole plate is located quite close to the ground, it is easy for the skater to bend and straighten his ankles. But, if the sole plate is located quite high off of the ground, it is difficult and even painful for the skater to bend and straighten his ankles.
In accommodating these two design criteria, i.e. upright wheels and a low sole plate, it was found that they were in substantial opposition. That is, in order for the center line of the sole plate to be positioned vertically over the tireground contact point, the height of the sole plate above the ground increased as the wheels became more upright. Therefore, to lower the position of the sole plate, the wheels had to be canted more. But this reduced the permissible lean angle.
The preferred embodiment is not merely a compromise solution, but actually accomplishes the chief objectives of both design criteria by dishing the wheels. That is, the dished wheel has all of the narrow profile, improved bearing operation, and reduced rolling friction advantages of an upright flat. wheel lying in the plane of line AA. Also, the dished wheel has all of the low sole plate advantages of a more steeply angled flat wheel lying in the plane of line B-B. In other words, the dished wheel combines the advantages of an upright flat wheel which is canted at an angle a or 33, and a more steeply angled flat wheel which is canted at an angle B or 54.
In order to lower the sole plate location in the dished wheel, the sole plate outer margin 26, and specifically ball portion margin 28, are dropped into the concavity below the level of the plane of the front wheel tire 58, as shown in FIG. 2. It can be seen that if front wheel 48 were flat (i.e. in the plane of line AA), instead of being dished, sole plate 10 could not be mounted as low as it is in FIG. 2. This is the advantage of the dished wheel configuration. It is a feature of this invention that sole plate 10, in the ball portion especially, is mounted below the level of the point of intersection of the axis of the front wheel axle 42 with the plane AA of the front wheel tire 58, which is indicated by horizontal line I-I-I-I. Furthermore, the sole plate upper surface has portions which are spaced above the ground a distance which is less than 40% of the wheel diameter.
Several other features of the sole plate will now be described. Referring to FIG. 1, sole plate 10 will be seen to have a width which beginning at the front or toe is first narrow, then wide, then narrow, and finally wide. This configuration, which is shaped on the wheel side by outer margin 26, permits the tires of the dished wheels to rotate very closely to each other adjacent to the narrow arch portion margin 16 of the sole plate. It also permits the skaters shoe itself (as well as ball portion margin 28) to be accommodated within the concavity of dished front wheel 48. Finally, the sole plate preferably has a raised rear portion which corresponds to the high heel of a figure skate used on ice. This high heel feature enables the skater to perform more graceful maneuvers than he could without it.
In use, the skate of this invention can be used on many surfaces and combines many of the best features of both ice skates and conventional roller skates. It can be manufactured in expensive sophisticated versions or in inexpensive simple versions. It is believed to be a marked improvement over previous efforts to design and construct a comfortable roller skate which is also a high performance roller skate.
The above description obviously suggests many possible variations and modifications of this invention which would not depart from its spirit and scope. It should be understood, therefore, that the invention is not limited in its application to the details of structure specifically described or illustrated and that within the scope of the appended claims, it may be practiced otherwise than as specifically described or illustrated.
1. A roller skate comprising:
a. a sole plate having a ball portion and a heel portion on its upper surface to accommodate the corresponding parts of a skaters foot or shoe thereon, said sole plate having rigid front and rear axle mount portions along its outer margin at locations laterally aligned with said sole plate ball and heel portions, respectively;
b. foot engaging means affixed to said sole plate for gripping and securely maintaining the skaters foot or shoe against the upper surface of said sole plate;
0. a front axle and a rear axle mounted in and extending downwardly from said front and rear axle mount portions, respectively, said axles being parallel to each other and being angled downwardly in excess of 28 with respect to the horizontal;
d. a front wheel and an equal diameter rear wheel mounted for rotation on the outer ends of said front axle and said rear axle, respectively, said wheels having ground contacting points positioned vertically beneath the approximate front to rear center line of said sole plate; and
e. a toe stop mounted on the front end of said sole plate, said top stop extending forward of said front wheel periphery;
f. the point of intersection of the axis of said front wheel axle with the plane of said front wheel periphery being located in a horizontal plane which is above the upper surface of said sole plate ball portion;
g. the point of intersection of the axis of said rear wheel axle with the plane of said rear wheel periphery being located in a horizontal plane which is below the upper surface of said sole plate heel portion;
h. said front wheel periphery and said rear wheel periphery being spaced apart at their points of closest proximity by a distance which is less than l0% of the combined diameters of said wheels.
2. The roller skate of claim 1 wherein said front wheel is dished toward said sole plate, said sole plate outer margin extending into the concave dished portion of said front wheel.
3. The roller skate of claim 2 wherein the lateral horizontal distance between the sole plate center line and said outer margin is greater across said sole plate ball portion and across said sole plate heel portion than is the lateral horizontal distance between the sole plate center line and said outer margin across the sole plate arch portion.
4. The roller skate of claim 3 wherein said rear wheel is dished in the identical shape of said front wheel.
5. The roller skate of claim 1 wherein said foot engaging means is adjustably affixed to said sole plate to permit adjustment thereof to accommodate differing foot or shoe sizes.
6. The roller skate of claim 1 wherein said sole plate upper surface has portions thereof which are spaced a distance above the ground which is less than 40% of the diameter of said wheels.
7. The roller skate of claim 1 wherein said sole plate upper surface has portions thereof which are spaced a distance above the ground which is less than the greatest width of said sole plate.
8. The roller skate of claim 1 wherein tires are mounted on said wheels at an angle which is the same as the angle which said wheels form with the vertical, said tires rolling squarely on the ground.
9. The roller skate of claim 1 wherein said sole plate is a one piece integral structure having sufficient strength to accommodate the applied static and dynamic loadings.
10. The roller skate of claim 1 wherein said foot engaging means acts to position and continuously urge the skaters foot or shoe against said sole plate outer margin.
11. The roller skate of claim 2 wherein the skaters foot or shoe extends into the concave dished portion of said front wheel.
12. The roller skate of claim 2 wherein the plane of said front wheel periphery forms an angle within the range of 30 to 33 relative to the vertical.