US3694958A

US3694958A - Wheel and axle assembly having an entrapped thrust bearing

Info

Publication number: US3694958A
Application number: US93348A
Authority: US
Inventors: John C Parker; Keith M Johnson
Original assignee: Mattel Inc
Current assignee: Mattel Inc
Priority date: 1970-11-27
Filing date: 1970-11-27
Publication date: 1972-10-03
Anticipated expiration: 1989-10-03
Also published as: FR2115767A5; GB1299052A; DE2105192A1; CA927603A

Abstract

An improved low-friction carriage for a toy vehicle where the wheels are each of one-piece construction including an axle bearing surface and a precisely concentric outer running surface. The wheel is retained by blunting the end portion of the corresponding axle and press fitting a steel ball in another opening of the wheel to act as a thrust bearing. Not only is friction reduced, but the axle, the wheel and the steel ball are economical elements which are easily and inexpensively assembled.

Description

United States Patent Parker et al.

154] WHEEL AND AXLE ASSEMBLY HAVING AN ENTRAPPED THRUST BEARING [72] Inventors: John C. Parker, Los Angeles; Keith M. Johnson, South Laguna, both of Calif.

[73] Assignee: Mattel, Inc., Hawthorne, Calif.

[22] Filed: Nov. 27, 1970 [21] Appl. No.: 93,348

[52] US. Cl. ..46/201, 29/1495, 29/453, 29/522, 46/221, 308/159 [51] Int. Cl. ..A63h 17/26 [58] Field of Search ..29/434, 443; 46/221, 222, 223, 46/201 [56] References Cited UNITED STATES PATENTS 3,566,536 3/1971 Baynes et a1 ..46/221 3,613,307 10/1971 Haynes et al ..46/221 51 Oct. 3, 1972 1,975,083 [0/1934 Cavanagh ..46/201 3,510,981 5/1970 LaBrancheetal ..46/221X FOREIGN PATENTS OR APPLICATIONS 824,916 12/1951 Germany .46/221 1,180,292 10/1964 Germany ..46/221 Primary Examiner-F. Barry Shay AttorneySeymour A. Scholnick [5 7] ABSTRACT An improved low-friction carriage for a toy vehicle where the wheels are each of one-piece construction including an axle bearing surface and a precisely concentric outer running surface. The wheel is retained by blunting the end portion of the corresponding axle and press fitting a steel ball in another opening of the wheel to act as a thrust bearing. Not only is friction reduced, but the axle, the wheel and the steel ball are economical elements which are easily and inexpensively assembled.

9 Claims, 4 Drawing Figures WHEEL AND AXLE ASSEMBLY HAVING AN ENTRAPPED TI-IRUST BEARING BACKGROUND OF THE INVENTION 1 Field of the Invention The present invention relates generally to toy vehicles and, more particularly, to a freely rotatable wheel and method for assembly whereby the frictional forces acting upon the wheel when it is rotated are reduced and the mode of assemblying the wheel to a vehicle minimize costs.

2. Description of the Prior Art Small toy vehicles in the form of automobiles have become exceedingly popular. These vehicles generally have metal bodies suitably attached to a carriage with freely rotatable wheels mounted to very small diameter wire axles, as exemplified by U.S. Pat. No. 3,510,981 to H. W. La Branche et al. The great majority of these vehicles are propelled by the force of gravity thereby necessitating a starting position on a running surface at some level vertically higher than the remainder of the running surface. Because the vehicles are propelled by the force of gravity, frictional forces generated due to movement of the vehicle critically affect the vehicless maximum speed and distance of movement. Thus, it is of utmost importance to have moving parts which keep the frictional forces or drag on the vehicle to a minimum.

To successfully mass market toy vehicles, it is necessary to minimize the cost of manufacturing and assembly so as to be economically acceptable.

SUMMARY OF THE INVENTION The present invention fulfills the necessary requirements mentioned above and provides an improved toy vehicle carriage comprising a support frame; at least two axles, one axle connected to one end portion of the support frame and the other axle connected to the other end portion of the support frame; at least four wheels, two connected to each of the axles wherein each of the wheels include an outer running surface, a first opening concentric with the running surface for receiving an end portion of one of the axles, the surrounding wall of the opening forming a bearing surface, and a second opening aligned with the first opening for receiving a thrust bearing element, the wheel being formed of resilient material; and at least four spherical thrust bearings each entrapped within a second opening of one of the wheels whereby a low-friction, lowcost carriage is provided. The invention further comprises the assembly including the wheel already described, an axle and a spherical thrust bearing. Further, the invention herein includes the wheel structure which is a unitary element and the method by which the wheel is assembled and retained to an axle.

It is a general aim of the present invention to provide a toy vehicle carriage with freely rotatable wheels which is inexpensive to manufacture and to assemble.

Another aim of the present invention is to provide a toy vehicle carriage of sufficient resiliency so as to relieve stress on the attached axles.

Another aspect of the present invention is to provide a wheel assembly having a low-rolling friction which is simple in construction, reliable in operation, inexpensive to manufacture and exceedingly easy to assemble.

A corollary object of the present invention is to provide a toy vehicle wheel of high precision construction, especially the distance between the outer running surface and the opening receiving the axle about which the wheel rotates and yet, be easily and cheaply manufacturable as a unitary element.

Still another aspect of the present invention is to provide a method of assemblying a wheel to an axle with a minimum of material, machine and labor costs.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of a toy vehicle carriage positioned on a track section.

FIG. 2 is a sectional elevational view of the toy vehicle carriage taken along line 2-2 of FIG. 1.

FIG. 3 is a bottom plan view of the toy vehicle carriage of FIG. 1.

FIG. 4 is an enlarged elevational sectional view of a modified portion of the view shown in FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT While the present invention is susceptible of various modifications and alternative constructions, an illustrative embodiment is shown in the drawing and will herein be described in detail. It should be understood, however, that it is not the intention to limit the invention to the particular forms disclosed; but, on the contrary, the intention is to cover all modifications, equivalents and alternative constructions falling within the spirit and scope of the invention as expressed in the appended claims.

Referring to FIG. I, there is illustrated a toy vehicle carriage 10 positioned on a track section 12. The track section 12 represents a portion of a track layout having a number of track sections connected end to end so as to provide a roadway for a toy vehicle. The track section includes a support portion 14 having a running surface 16 and two oppositely disposed obliquely extending guide flanges l8 and 20. The guide flanges l8 and 20 guide the wheels of the toy vehicle to ensure that the vehicle remain on the running surface 16. Two depending

flanges

22 and 24 form with a bottom surface 26, a channel-shaped receptacle to receive a track section connector to allow the track section 12 to be con nected to an abutting track section or to various types of track layout accessories, such as curves, loops, jump ramps etc. The provision of a track section as part of a roadway ensures the vehicle a smooth, flat surface over which it may travel thereby enhancing speed and reducing friction on the vehicle. A fuller explanation of the track section is found in U.S. Pat. No. 3,487,999 to A. W. B. Nash et al.

The carriage is comprised of a support frame 30, four embedded

axles

32, 34, 36 and 38, FIGS. 1 and 3, and four

wheel assemblies

40, 42, 44 and 46. It is contemplated that the support frame will be suitably attached to a vehicle body (not shown) which may take the shape of a toy automobile, a toy motorcycle, a toy train or any other toy form where it is desired to attach a wheeled mechanism to allow movement.

An important aspect of the present invention is to provide a wheel and wheel assembly which is simply constructed, inexpensively manufactured and inexpensively assembled and yet, minimizes the friction generated upon rotation of the wheel. Referring to FIG. 4, there is illustrated in more detail the wheel assembly 46 which includes a one-piece wheel structure 48 of a resilient material, such as a synthetic resin, having an outer surface divided into a relatively smaller diameter wide portion 50 and a larger diameter narrow portion 52 which includes the outer wheel surface making contact with the running surface 16, FIG. 1, of the track section 12. As pointed out in the above-mentioned La Branche et al. patent, drag on a vehicle is greatly reduced by making the contact between the vehicle and the track section running surface as small as possible. Thus, the wheel assembly has a fairly small contact with the running surface on which it moves, yet, has the appearance and style of a very wide wheel which closely simulates real wide-body racing tires enjoying current popularity.

The wheel 48 includes a central opening 54 having a cylindrical wall 56 which acts as a bearing surface against the axle 38. Aligned with the opening 54 so as to have coincident central longitudinal axes is a second opening 58 of a larger diameter than the opening 54 and also having a generally cylindrically shaped surrounding wall 60. An interior annular recess 62 is formed in the wall 60 at a slight distance from an outer lateral surface 64 of the wheel. A truncated conical surface 66 connects the wall 60 of the larger opening 58 with the wall 56 of the smaller opening 54. The opening 54 is made precisely concentric with the running surface 52 so as to allow free rotation about the axle 38. This is achieved easily with the present wheel structure because it is molded as an integral unit and does not require the alignment of a second bearing element as disclosed in the above-mentioned La Branche et al. patent. To limit wheel lateral motion or motion parallel to the longitudinal axis of the axle 38, an end portion 70 of the axle is expanded such as by being swaged so as to have a larger dimension or diameter than the diameter of the opening 54. Thus, movement of the wheel in a leftward direction, as viewed in FIG. 4, is prevented due to the abutment of the expanded end portion 70 and the wall 66. It is noted that the slope of the wall 66 and the geometry of the end portion 70 are such as to provide minimum area contact when abutment occurs; this feature minimizes frictional drag on the rotation of the wheel 48. To additionally ensure a minimum of generated friction, the end portion has a substantially smooth end surface 72 which selectively comes into contact with a spherical thrust bearing 74. The thrust bearing 74 may be a small steel ball and is located within the opening 58 and entrapped in a stationary position relative the wheel by the annular recess 62 so as to provide a spacing between the spherical bearing and the end surface 72 of the axle. An annular lip 73 prevents the bearing from removing itself. Movement of the wheel in a rightward direction, as viewed in FIG. 4, is thus limited by the abutment of the flat surface 72 and the surface of the spherical bearing. Because the contact between the surface 72 and the spherical bearing is intermittent, friction is minimized, and when contact does occur, it is along a fairly small area of the spherical bearing and the flat end surface of the axle so as to additionally minimize friction generated. It is noted that a spacing 75 is provided between the thrust bearing and the end surface of the axle so that friction generating contact is not continuous between these elements; contact occurs only when lateral forces move the wheel to the right.

To further ensure a minimum of friction being generated by the rotation of the wheel, a suitable silicone emulsion may be applied to the spacing between the bearing wall 56 and the axle 38.

The ease of manufacture is achieved by the fact the wheel 48 is of a one-piece construction. Assembly of the wheel and the axle is also easily and economically accomplished by simply passing the axle through the opening 54 until the end portion '70 of the axle is within the spacing 58. The end portion is then swaged to expand its dimension thereby locking in one axial direction the position of the wheel. Next, the spherical thrust bearing 74 is press fitted into the opening 58 until engagement is made with the annular recess 62. Since the material of the wheel is resilient, the thrust bearing may be easily and mechanically inserted with the wheel material springing back to its original form to ensure a locking engagement of the thrust bearing in the wheel. Each of the

other wheel assemblies

40, 42 and 44 are similarly constructed and assembled. it is noted that the thrust bearings not only perform a functional role but also an aesthetic role by providing an attractive appearance to each of the wheel assemblies.

The structure of the wheel and the use of spherical bearings are inexpensive; that is, the wheel is easily and economically formed by a one-step molding operation and steel balls with known dimensional tolerances are readily available. Further, the steel ball is very easy to handle, feed and insert using known production assembly eq uipment.

Another important aspect of the present invention is achieved by the provision of the resilient support frame 30 which reduces the stress induced in the axles. As mentioned, the axles are of very small diameter wire and therefore, unable to carrying excessive bending loads. Referring to FIGS. 2 and 3, the support frame 30 is comprised of a unitary piece of synthetic resin which is suitably molded to a desired shape. For example, the support frame includes a U-shaped end portion for supporting the

wheel assemblies

44 and 46 and a U- shaped end portion 82 for supporting the

wheel assemblies

40 and 42. Connecting the two U-shaped end portions is a central elongated portion 84. In the particular embodiment disclosed, there are four axles as already mentioned, 32, 34, 36 and 38 each of which is embedded in a corresponding end portion, such as the

axles

36 and 38 being embedded in the end portion 80 while the

axles

32 and 34 are embedded in the end portion 82. The support frame 30 may be molded as a unitary piece in the shape shown, and the axles may he embedded by providing the placement of the axles within the mold before the heated synthetic resin is injected. This may be accomplished by initially providing the

axles

32 and 34 as a single strand of wire with the central portion illustrated in dotted line and designated 86 being removed after the support frame has cooled and been removed from the mold. The

axles

36 and 38 may be embedded in a like manner. It is to be understood, however, that the particular form of the support frame is not to be considered as limiting the invention herein. For example, the support frame may simply comprise an elongated strip of synthetic resin material with a strand of small diameter wire embedded at either end to form the four axles needed for a toy automobile. it is to be further understood that more than one wheel may be mounted at each axle if the toy vehicle simulates a real vehicle having multiple wheels at an axle.

It is contemplated that the support frame will be attached to a vehicle at or about a lateral lug 88 integral with the central portion 84 so that the two legs of the U-shaped end portions are flexible in response to forces being applied to the wheel so as to reduce the stresses induced in the axles.

We claim:

1. A toy vehicle carriage comprising:

a support frame;

at least one axle connected to said support frame and having an outer end with means for retaining a wheel thereon;

a wheel mounted to said axle for abutment with said retaining means, said wheel including an outer running surface, a first opening concentric with said running surface surface for receiving an end portion of said axle, the surrounding wall of said opening forming a bearing surface, and a second opening aligned and communicating with said first opening for accommodating therein said retaining means and for receiving a thrust bearing element, said wheel being formed of resilient material; and

a spherical thrust bearing entrapped within said second opening of said wheel whereby said retaining means is trapped between said thrust bearing and a portion of said wheel.

2. A toy vehicle carriage, as claimed in claim 1,

wherein:

said first opening of said wheel is cylindrically shaped; and

said retaining means comprises an expanded end portion having a larger diameter than said first opening whereby said wheel is restrained in movement in a direction parallel to the longitudinal axis of said axle.

3. A toy vehicle carriage, as claimed in claim 2,

wherein:

said second opening of said wheel is surrounded by a wall having an inner recess to receive and entrap said spherical thrust bearing; and said expanded end portion of said axle is positioned within said second opening so as to provide a spacing between said end portion and said thrust bearing.

4. A toy vehicle carriage, as claimed in claim 3,

wherein said support frame is resilient.

5. A toy vehicle carriage, as claimed in claim 4, wherein said axle is embedded within said resilient support frame.

6. A toy vehicle carriage, as claimed in claim 5, wherein said wheel includes an outer surface having a wide smaller diameter, non-running portion and a narrow larger diameter portion including said outer running surface.

7. A toy vehicle wheel assembly comprising:

a wheel having an outer running surface, a first cylindrical opening concentric with said running surface for receiving an axle, the surrounding wall of said opening forming a bearing surface, and a second opening aligned and communicating with said first o e in rust bearin element in said second op niiiggthrust bearl ng element having a diameter greater than a portion of the wall which forms said second opening for entrapment of said thrust bearing element in said second opening, said whee] being resilient enough to permit said thrust bearing element to be forced into said second opening behind said wall portion thereof; and i an axle positioned within the first opening and having an enlarged end portion of diameter greater than the diameter of said first opening.

8. A wheel assembly, as claimed in claim 7, wherein the wall surrounding said second opening has an inner recess to receive and entrap said thrust bearing element so as to provide a spacing from the enlarged end portion of said axle.

9. A wheel assembly, as claimed in claim 8, wherein said wheel is a unitary element formed of a resilient material; and said thrust bearing element is spherical.

Claims

1. A toy vehicle carriage comprising: a support frame; at least one axle connected to said support frame and having an outer end with means for retaining a wheel thereon; a wheel mounted to said axle for abutment with said retaining means, said wheel including an outer running surface, a first opening concentric with said running surface surface for receiving an end portion of said axle, the surrounding wall of said opening forming a bearing surface, and a second opening aligned and communicating with said first opening for accommodating therein said retaining means and for receiving a thrust bearing element, said wheel being formed of resilient material; and a spherical thrust bearing entrapped within said second opening of said wheel whereby said retaining means is trapped between said thrust bearing and a portion of said wheel.

2. A toy vehicle carriage, as claimed in claim 1, wherein: said first opening of said wheel is cylindrically shaped; and said retaining means comprises an expanded end portion having a larger diameter than said first opening whereby said wheel is restrained in movement in a direction parallel to the longitudinal axis of said axle.

3. A toy vehicle carriage, as claimed in claim 2, wherein: said second opening of said wheel is surrounded by a wall having an inner recess to receive and entrap said spherical thrust bearing; and said expanded end portion of said axle is positioned within said second opening so as to provide a spacing between said end portion and said thrust bearing.

4. A toy vehicle carriage, as claimed in claim 3, wherein said support frame is resilient.

7. A toy vehicle wheel assembly comprising: a wheel having an outer running surface, a first cylindrical opening concentric with said running surface for receiving an axle, the surrounding wall of said opening forming a bearing surface, and a second opening aligned and communicating with said first opening, a thrust bearing element in said second opening, said thrust bearing element having a diameter greater than a portion of the wall which forms said second opening for entrapment of said thrust bearing element in said second opening, said wheel being resilient enough to permit said thrust bearing element to be forced into said second opening behind said wall portion thereof; and an axle positioned within the first opening and having an enlarged end portion of diameter greater than the diameter of said first opening.