Claims:
I claim
1. A hockey puck comprising a circular disk of moldable, slightly resilient, material, a first set of depressions formed in one circular face of the disk, a second set of depressions formed in the other circular face of the disk, each depression having a truncated spherical shape, a spherical roller mounted and retained in each depression with a minor portion thereof extending from the depression, each depression of the first set on the one face, if projected to the other face along a line parallel to an axis joining the centers of the circular faces, being laterally offset from the depressions on the other face.
2. A hockey puck as claimed in claim 1, wherein each depression of each set is located substantially the same radial distance from the axis joining the centers of the circular faces.
3. A hockey puck as claimed in claim 2, wherein each depression of the first set is laterally offset to a position midway between adjacent depressions of the second set.
4. A hockey puck as claimed in claim 2, wherein the depressions in each set are substantially equally spaced from one another.
5. A hockey puck as claimed in claim 2, wherein the depressions are adjacent a side edge of the disk joining the first and second faces.
6. A hockey puck as claimed in claim 5, wherein a central, circular recess is formed in each circular face of the disk.
7. A hockey puck as claimed in claim 6, wherein each depression is radially positioned substantially midway between the radius of the recesses and the radius of the faces.
8. A hockey puck as claimed in claim 2, wherein the hockey puck is molded from polyethylene.
Description:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an improved hockey puck having roller means so it can be more easily used for playing on other surfaces in addition to ice.
The invention is more particularly directed toward an improved hockey puck having spherical rollers mounted in each face of the puck, the rollers in one face located in different areas relative to the location of the rollers in the opposite face.
2. Description of the Prior Art
The mounting of rollers in hockey pucks is known. However, it has been difficult to provide mountings for spherical rollers in a molded puck which are dimensionally accurate. Directly forming socket mountings during the molding of a puck usually results in mountings for spherical rollers which are out of round, thus causing binding of the rollers fitted in the sockets. In order to properly mount and retain the rollers to obtain a suitable rolling action, special mounting frames have been employed as shown in Canadian Pat. No. 527,738, issued July 17, 1956, Andrew C. Watson, inventor, for example. The mounting frame is molded within the puck, and the rigid sockets, for receiving the balls, remain dimensionally accurate during molding thereby ensuring a proper rolling action. The frame, however, is quite expensive and increases the cost of manufacturing the puck.
SUMMARY OF THE INVENTION
Applicant has discovered that the roller mountings may be formed directly in the puck during molding without distortion and without the necessity of using a rigid frame, provided the roller mountings on the opposed faces are located in a certain manner with respect to each other. The improved puck is simple and inexpensive to manufacture while still retaining good rolling properties.
The invention is particularly directed toward a hockey puck comprising a circular disk of moldable, slightly resilient material, a first set of depressions formed in one circular face of the disk, a second set of depressions formed in the other circular face of the disk, each depression having a truncated, spherical shape, a spherical roller mounted and retained in each depression with a minor portion thereof extending out of the depression, each depression of the first set on the one face, if projected to the other face along a line parallel to an axis joining the centers of the circular faces, being laterally offset from the depressions of the second set.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described in detail having reference to the accompanying drawings, wherein:
FIG. 1 is a schematic view of the improved hockey puck;
FIG. 2 is a plan elevation view showing the positions of the rollers in both faces; and
FIG. 3 is a cross-sectional view taken along line 3--3 of FIG. 2.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The hockey puck comprises a cylindrical disk 1 made out of moldable, slightly resilient, material. The material can be a suitable polymer, such as polyethylene. A first set 3 of depressions 5 is formed in one face 7 of the puck during molding while a second set 9 of depressions 11 is formed in the other face 13 of the puck during molding. Each depression 5, 11 preferably has a truncated spherical shape, as shown in FIG. 3. Mounted in each depression, after molding, is a spherical ball 15 so that a minor portion of the ball projects from the depression. Each depression is sized to provide an annular edge or lip 17 which serves to retain the ball 15 within the depression. The balls are inserted into the depressions under pressure, the lips 17 expanding slightly to permit the balls to pass into the depressions and then returning to their original shape to retain the balls in the depressions.
The first and second sets 3, 9 of depressions are each arranged in a circle with the depressions in each circle substantially equally spaced from one another. Preferably, each depression 5, 11 is located the same radial distance R from a central axis joining the centers of the circular faces 7, 13 together.
Each depression 5 of one set 3, if projected from its face 7 to the opposite face 13 along a line parallel to the axis joining the centers of the circular faces, is laterally offset from the depressions 11 in the other face 13. Preferably, as shown in FIG. 2, each depression 5 of the first set 3 is offset circularly to a position where it lies substantially midway between two adjacent depressions of the second set 9.
Each set 3, 9 of depressions is preferably located adjacent the edge or side wall 23 of the circular disk 1 to provide stability. It is preferred to mount six balls 15 on each face although more or less can be used.
It is essential to have the depressions 5 of one set 3 laterally offset from the depressions 11 of the other set 9. This ensures that the truncated spherical shape of each depression is substantially retained after molding. If, as has been normally done, each depression of one set 3 was axially aligned with a respective depression on the second set 9, stresses would be set up during the molding of the depressions. These stresses would, after molding, be relieved, and result in the depressions assuming a non-spherical shape.
It has been found that the shape of each depression is better retained after molding if a central, circular, shallow recess 25, 27 is formed in each face 7, 13 of the puck during molding. The recesses 25, 27 result in the formation of a thin central web 29 and annular surfaces 31, 33. The circular rows of depressions of each set 3, 9 are preferably located midway between the inner and outer radius R', R" of each annular surface. This results in a further reduction in stresses set up during the molding operation. The recesses 25, 27 also result in less material being required to mold the puck and also reduce the time required to mold the puck since the molded puck can be cooled and removed from the mold more rapidly. Each recess 25, 27 preferably has a depth equal to the depth of the depressions.