US3552003A

US3552003A - Method of making slot car racetracks

Info

Publication number: US3552003A
Authority: US
Inventors: Bhaskar Kumar Agarwala
Original assignee: Revell Inc
Current assignee: Revell Inc
Priority date: 1969-01-08
Filing date: 1969-01-08
Publication date: 1971-01-05
Anticipated expiration: 1988-01-05

Abstract

A UNITARY SLOT CAR RACETRACK COMPRISES A THERMOPLASTIC SUBSTRATE HAVING A CONTINUOUS SLOT OF DESIRED CONFIGURATION FORMED THEREIN. A PAIR OF TIN-COATED STEEL FOIL STRIPS ARE ADHESIVELY SECURED TO THE SUBSTRATE SURFACE ON EITHER SIDE OF THE SLOT AND EXTEND OVER THE EDGES OF THE SLOT AND DOWNWARDLY ALONG THE SIDEWALLS THEREOF.

Description

Jan. 5, 1971 K. AGARWALA METHOD OF MAKING SLOT CAR RACETRACKS Filed Jan. 8, 1969 INVENTOR 5. [50/1445 AGAEWACA BY KE/VOE/Clfand SUBL OM/ United States Patent US. Cl. 29-625. 6 Claims ABSTRACT OF THE DISCLOSURE A unitary slot car racetrack comprises a thermoplastic substrate having a continuous slot of desired configuration formed therein. A pair of tin-coated steel foil strips are adhesively secured to the substrate surface on either side of the slot and extend over the edges of the slot and downwardly along the sidewalls thereof.

The improved track is formed by heating the thermoplastic substrate to soften it, die-forming the slot in the softened substrate, cutting a tin-coated and adhesivebacked strip of steel foil into substantially the configuration of the slot, perforating the steel foil strip along the centerline thereof, laying the perforated strip on the substrate with the line of perforations substantially overlying the slot, and pressing against the steel foil strip with a layer or roller of soft rubber material to substantially simultaneously 1) adhere the lateral edges of the strip to the substrate surf-ace adjacent the slot, (2) sever the strip along its line of perforations, and (3) adhere the severed edges of the strip to the sidewalls of the slot.

The present invention relates generally to slot car racin-g games, and more specifically to an improved slot car racetrack and method for forming the track.

BACKGROUND OF THE INVENTION Slot car racing games are becoming increasingly popular throughout the world. The game is played by racing miniature cars on a racing track. The track comprises a series of parallel slots or grooves formed in a substrate or track base, and the cars carry guide pins which extend into the slots so that the cars will follow the contour or configuration of the slots when they are propelled. Each car straddles a slot and carries an electric motor which turns the wheels to drive the car along the track. Power is supplied to each electric motor by a pair of brushes which are carried by each car and contact a pair of conductive strips or electrodes secured to the track base on opposite sides of each groove. Each pair of electrodes, in turn, is connected to a source of electrical potential.

Heretofore, the slot car tracks have been formed in individual modular components which had to be connected to one another to form the completed track assembly. Each of the modules comprised an extruded thermoplastic section having straight or curved slots extending therealong, and precision-cut electrode strips secured to the upper surface of the module along either side of each slot.

Several disadvantages were presented by this track and method of forming it. The extruded plastic modules were relatively expensive to manufacture, as were the electrode strips which had to be precision-cut to correspond to the contour or pattern of the slot. The more complex the configuration of the slots, the more expensive it was to manufacture the track. Moreover, the individual track modules had to be fitted together, and if good contact was not made between each adjacent set of electrode strips, power would not be supplied to the electric motors in the racing cars.

Still another disadvantage of the prior art track was that the guide pin on each racing car caused wear in the Patented Jan. 5, 1971 slot in which it rode as the car moved along the track. Such wear developed an increasingly high friction interface between the pin and the slot and lowered the maximum speed at which the cars could be driven.

In view of the foregoing, it is an object of the present invention to provide an improved slot car racing track and method of producing the same which obviate the disadvantages and deficiencies discussed above.

SUMMARY OF THE INVENTION The foregoing and other objects and advantages have been realized by the improved slot car racing track and process of the present invention. Briefly, the improved process comprises forming a continuous slot in a desired configuration in a substrate, cutting a continuous strip of electrically conductive sheet material into substantially the configuration of said slot, perforating the strip substantially along the centerline thereof to form a perforated line corresponding to the configuration of the slot, laying the perforated strip over the slot and aligning the strip so that the perforated line substantially overlies the slot and the lateral edges of the strip overlie the substrate surface adjacent the edges of the slot, and pressing a body of relatively soft material against the strip to simultaneously press the lateral edges of the strip into engagement with the substrate surface, sever the strip along the perforated line, and press the severed edges of the strip into engagement with the sidewalls of the slot.

The finished track comprises a substrate having one or more continuous slots formed therein with a pair of substantially parallel electrode strips overlying the opposite edges of each slot and extending downwardly along the side walls of the slot. The track is a unitary structure, manufactured at a cost which is substantially independent of the complexity of the slot configurations. The severed edges of the electrode strips which extend along the sidewalls of the slots prevent the racing car guide pins from causing wear in the slots.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a perspective view showing a slot car racetrack constructed in accordance with the teachings of the present invention;

FIG. 2 is a partial perspective view illustrating one of the steps in the process of the present invention, wherein a perforated strip of conductive material is about to be applied to a section of the racetrack substrate; and

FIGS. 3 and 4 are partial vertical section views showing the perforated strip being applied to the substrate.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Referring now to the drawings, FIG. 1 shows a pair of

miniature slot cars

10, 12 racing on track 14 constructed in accordance with the teachings of the present invention. The track substrate or base 16 has a pair of slots or

grooves

18, 20 formed therein, and the

cars

10, 12 carry guide pins (not shown) which ride in these slots.

The improved track forming process of the present invention is illustrated in FIGS. 2-4. (Initially, a slot groove 22 is formed in the thermoplastic substrate or base 16 by heating the substrate to soften it, and vacuum forming it or pressing it against a suitable die (not shown) having the desired slot configuration formed thereon. Thereafter, an electrically conductive strip 24 is cut to the configuration of the slot 22 and perforated as at 26 along its centerline.

As best shown in FIGS. 3 and 4, the conductive strip 24 comprises a sheet of steel foil 28 coated on its upper surface with a layer of tin 30 and on its lower surface with a layer of adhesive 32.

Next, the strip 24 is layed over the slot 22 and aligned so that the perforations 26 lie approximately over the center of the groove 22 and the

lateral edges

34, 36 of the strip overlie the slot edges 38, 40 (FIG. 3).

With the conductive strip so aligned, a layer of soft rubber material 42 is pressed downwardly on the strip 24 (FIG. 4) to 1) press the

lateral edges

34, 36 of the strip into engagement with the substrate surface adjacent the slot edges 38, 40 (2) sever the strip along the line of perforations 26, and (3) press the

severed edges

44, 46 of the strip into engagement with the upper portions of the

sidewalls

48, 50 of the slot 22. The soft rubber 42 will fill the slot 22 (as shown in FIG. 4) to firmly press the severed

strip edges

44, 46 into engagement with the

sidewalls

48, 50 and cause them to adhere thereto. The rubber layer 42 is then removed, leaving the severed

conductive strips

24, 24 adhesively secured around the

edges

38, 40 of the slot 22.

Alternatively, a soft rubber roller (not shown) may be employed in place of the rubber layer 42.

As will be appreciated from the foregoing, the finished slot car racing track 14 can be manufactured relatively inexpensively by the method of the present invention, with the cost of manufacture being virtually independent of the complexity of the configuration of the slots. Moreover, the finished track has several desirable features. The track is a unitary structure, which does not require assembly of individual modules and the attendant disadvantages discussed above. In addition, the

severed edges

44, 46 of the strip 24 overlie the

sidewalls

48, 50 of the slot 22 (FIG. 4) to form low friction slide surfaces which the racing car guide pins (not shown) prevent wearing of the slot.

Since the

electrode strips

24, 24 do not have to be precision cut and handled, they may be made thinner, and consequently less expensive. In addition, the tin plate coating 30 may be made thinner to better permeate the steel foil 28 and form a more corrosion resistant laminate.

If desired, the track substrate 16 may be imprinted with any suitable design (e.g., cobble stone) for esthetic purposes.

I claim:

1. A process for making a slot car racetrack, comprising:

forming a continuous slot in a desired configuration in a substrate surface; forming a strip of electrically conductive material into substantially the configuration of the continuous slot; perforating the strip substantially along the centerline thereof to form a perforated line corresponding to the configuration of the slot;

laying the perforated strip over the slot and aligning the strip so that the perforated line substantially overlies the slot and the lateral edges of the strip overlie the substrate surface on either side of the slot; and

pressing a body of relatively soft material into engagement with the strip to substantially simultaneously press the lateral edges of the strip into engagement 4 with the substrate surface on either side of the slot, sever the strip along the perforated line, and press the severed edges of the strip into engagement with the sidewalls of the slot. 2. A process for making a slot car racetrack according to claim 1, wherein the substrate is thermoplastic and the continuous slot is formed by heating the thermoplastic substrate to soften it and thereafter pressing the softened substrate into engagement with a die having the desired slot configuration formed thereon.

3. A process for making a slot car racetrack according to claim 1, wherein said step of forming a strip of electrically conductive material comprises cutting a strip of tin-coated, adhesive-backed steel foil into substantially the configuration of the slot.

4. A process for making a slot car racetrack according to claim 1, wherein the step of pressing a body of relatively soft material into engagement with the strip comprises pressing a layer of soft rubber against the strip.

5. A process for making a slot car racetrack according to claim 1, wherein said step of pressing a body of relatively soft material into engagement with the strip comprises rolling a soft rubber roller across the strip.

6. A process of forming a slot car racing track comprising the steps of:

forming a continuous slot in a desired configuration in a substrate surface;

forming a strip of electrically conductive material into substantially the configuration of the continuous slot;

perforating the strip substantially along the centerline thereof to form a perforated line corresponding to the configuration of the slot; laying the perforated strip over the slot and aligning the strip so that the perforated line substantially overlies the slot and the lateral edges of the strip overlie the substrate surface on either side of the slot; and

pressing a body of relatively soft material into engagement with the strip to substantially simultaneously press the lateral edges of the strip into engagement with the substrate surface on either side of the slot, sever the strip along the perforated line, and press the severed edges of the strip into engagement with the sidewalls of the slot.

References Cited UNITED STATES PATENTS 8/1960 Eisler 29-625X 7/1962 Cado 29-625X U.S. Cl. X.R.