US3646706A

US3646706A - Toy vehicle

Info

Publication number: US3646706A
Application number: US49599A
Authority: US
Inventors: Cecil F Adickes
Original assignee: Tonka Corp
Current assignee: Hasbro Inc
Priority date: 1970-06-25
Filing date: 1970-06-25
Publication date: 1972-03-07
Anticipated expiration: 1989-03-07

Abstract

A miniature toy vehicle having front and rear wheels and adapted to be propelled over a hard floor surface wherein the rear wheels are formed of a material having a higher coefficient of friction than the front wheels with respect to said floor surface to aid true tracking of the vehicle over the surface.

Description

[ 5] Mar. 7, 1972 United States Patent Adickes Smolinske et tn e m en h u n .n m m a "a .n f m "e e mmmm U01 e BTOT 890000 667777 999999 11111] Ill/ll 22302 11 11 mumamfl 2 2 2 834 25 089044 333333 E a 1 .m M M 1 d e m D o W M h 1 M a m A W E E 5 L 1 m 2 m w o m H C T J m m n z 0 w m M T .m A H l. l 1 4 2 3 2 5 7 7 2 l l [21] Appl. No.: 49,599

Primary Examiner-Louis G. Mancene Assistant Examiner-Robert F. Cutting Attorney-Carlsen, Carlsen & Sturm .46/201, 46/221 A63h 17/00 .46/201, 202, 221; 150/209 R;

[58] Field ofSear-ch. ABSTRACT ISO/L5 A miniature toy vehicle having front and rear wheels and adapted to be propelled over a hard floor surface wherein the {56] References Cited rear wheels are formed of a material having a higher coeffi- UNITED STATES N S cient of friction than the front wheels with respect to said floor surface to aid true tracking of the vehicle over the surface.

180/ 1.5 .46/202 4 Claims, 3 Drawing Figures mu 6 mm a HF 85 36 99 ll 9 20 39 56 00 23 PATENTEDMAR 7 1972 INVENTOR. 6601 F 190 ICKS BY %,w

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irrakwexf rov VEHICLE BACKGROUND OF THE INVENTION Miniature toy vehicles having high-speed wheel and axle assemblies are frequently used for amusement to travel over a preformed track or through a turnabout by gravitational descent or after shooting from a launching device. These vehicles, generally being fabricated of plastic or sheet metal material, are very light in weight. Accordingly, they tend to skid or spin when moving at relatively high speeds over a hard surface.

It is found that the skidding occurs in a relatively uncontrolled manner where all of the wheels have the same coefficient of friction with respect to the floor surface.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a toy vehicle which has an excellent tracking capability at relatively high speeds particularly where the surface over which the vehicle is moved has banked areas, turns or the like.

In order to accomplish this the invention generally comprises providing rear wheels or tires on the vehicle having a substantially higher coefficient of friction with respect to the floor or track surface than the front wheels or tires. This allows a desirable limited amount of lateral skidding of the front wheels as the vehicle is propelled about a banked curve or the like while the rear wheels tend to hold the track in a rolling condition. It is also found advantageous to provide rear wheels or tires with a larger external diameter than those on the front.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a scenic plan view showing a launching device at the left for propelling a toy vehicle across a floor surface or the like toward a turnabout at the right which causes the vehicle to make a U-tum and return toward the operator of the launching device.

FIG. 2 is a plan view of a toy vehicle embodying the present invention with the tires of the vehicle shown in diametrical section.

FIG. 3 is a side elevation of the vehicle with the tires thereof shown in longitudinal vertical section as on line 3-3 of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now more particularly to the drawings reference characters will be used to denote-like parts or structural features in the different views. The invention is particularly designed for use on miniature toy vehicles adapted to be propelled at high speeds over a hard floor surface. In FIG. 1 there is shown a launching device for launching one or two vehicles. It has a control housing 1 1 located between a pair of parallel launching platforms l2. Handles 14 may be operated to load spring mechanism within the housing 11 so that when the release buttons 15 are selectively depressed the launcher arms 16 will be released for forward movement by said spring mechanism to propel a vehicle 17 from one or both platforms 12 in a forward direction toward a turnabout 18. The turnabout has entrance and departure ramps 19 connected by a banked U-shaped wall 20 which provides the surface for the vehicle to reverse its direction and return toward the launching device 10. The toy vehicle having conventional tires will tend to skid or even roll over as it ascends the curved wall 20 or leaves the wall to return down a ramp 19.

The vehicle 17 has a pair of axially aligned front wheels 21 and a pair of axially aligned rear wheels 22. These may be individually journaled on front and rear axles fixedly mounted on the vehicle body 23. Preferably, however, the

wheels

21 and 22 are integrally mounted at the ends of an axle member that is journaled on the body. In either event the front wheels 21 carry tires 24 and the rear wheels 22 carry tires 25.

Tires

24 and 25 are formed of materials having different coefiicients of friction with the tires on the rear wheels having the hi her coefficient with respect to the surface to be traversed suc as turnabout 18.

The applicants assignee has conducted various experiments on tire materials to determine the coefficient of friction of the materials against a medium impact polystyrene surface such as could be used in the turnabout 18. Four materials of varying degrees of hardness were tested at different rates of speed between a static situation and 60 feet per minute. The materials tested were a styrene butydine product called (a) KRATON 3202 manufactured by Shell Oil Company and three grades of polyvinyl chloride, identified with increasing hardness as (b) 45, (c) 52 and (d) durometer.

It was determined that where it is desirable to have a laterally skidding vehicle straighten out as soon as possible, the rear tire material should have a high coefficient of friction with the surface material when the vehicle is traveling in the range of 60 feet per minute, and that the static coefficient of friction was of little importance. The materials (a), (b) and (c) above being softer than the material ((1) all had a much higher coefficient of friction at the 60 feet per minute speed.

Where material (d) is used on all four wheels the vehicle tends to spin and skid out of its desired path of travel. However, when the materials (a), (b) and (c) were used on the rear wheels and material (d) only on the front wheels, the vehicle even when propelled into a skidding situation will tend to straighten out with its wheels coming into rolling contact with the surface.

While any significantly higher coefficient of friction in the rear tires will cause improved tracking, it is found that the most effective combination where polyvinyl chloride is used is where the rear tire material has a durometer under 60 while the front tire material has a durometer over 75.

Having now therefore fully illustrated and described my invention, what I claim to be new and desire to protect by Letters Patent is:

1. In a toy vehicle adapted to be propelled over a given hard surfaced material, said vehicle having a pair of coaxial rear wheels having annularly smooth peripheral surfaces formed of a nonmetallic first material and having a pair of coaxial front wheels having their peripheral surfaces formed of a second material, said first material having a higher coefficient of friction with respect to said given material than said second material has with respect to said given material.

2. The subject matter of claim 1 wherein said rear wheels have a greater external diameter than said front wheels.

3. The subject matter of claim 1 wherein both said first and second materials are polyvinyl chloride with the durometer of the first material being lower than 60 and of the second material being greater than 75.

4. The subject matter of claim 1 wherein said pairs of wheels are each integrally mounted on an axle and respectively carry tires formed of said first and second materials.