GB2137892A - Toy vehicles - Google Patents

Abstract

A toy vehicle having an electric motor 21 arranged to drive at least one wheel axle shaft 24 thereof, the motor shaft 22 being perpendicular to the axle shaft, and a reduction gear train between the motor shaft and the axle shaft, said reduction gear train consisting only of a crown gear 26 and pinion gear 25 combination and a plurality of spur gears 27 to 32, the final spur gear 32 being secured on the axle shaft. <IMAGE>

Description

SPECIFICATION Toy Vehicles This invention relates to toy vehicles driven by an electric motor and is particularly concerned with improvements in the drive mechanism between the motor and the wheels thereof.

It is desirable that the electric motor for driving a toy vehicle should be arranged with its drive shaft extending lengthwise of the vehicle, to make best use of the available space. This makes it necessary to turn the rotary axis of the drive through 900 between the motor shaft and the wheel axle. One way of doing this is to incorporate a worm and worm gear arrangement in the drive. It is however a disadvantage of such an arrangement that, because of the presence of the worm/worm gear combination, the gear train locks if a user attempts to operate it in reverse by pushing the toy vehicle along the ground, and this quickly leads to worn and damaged gears.

According to the present invention there is provided a toy vehicle having an electric motor arranged to drive at least one wheel axle shaft thereof, the motor shaft being perpendicular to the axle shaft, and a reduction gear train between the motor shaft and the axle shaft, said reduction gear train consisting only of a crown gear and pinion gear combination and a pluraiity of spur gears, the final spur gear being secured on the axle shaft.

Such an arrangement enables the gear train to operate in reverse if the user pushes the vehicle along the ground as aforesaid, thereby avoiding the wear on the gears which previously resulted from the locking of the gear train in such circumstances.

Preferably the said pinion is secured on the motor shaft, i.e. is the first element of the drive train.

In one form of the invention the motor has a said shaft extending both forwardly and rearwardly therefrom, there being a said reduction gear train between each said motor shaft and a front and rear wheel axle shaft respectively, to provide four-wheel drive.

Another disadvantage of previous proposals is that the shafts of at least some of the gears have been journalled in two-part bushings defined only when two shells forming a gear box are brought together. This has often resulted in the shafts being either too tight or too loose a fit in their bushings, which leads to loss of power or noisy operation respectively. In a preferred form of the present invention, therefore, where the toy vehicle includes a gear box housing the said gear train(s), each of the said gears other than the said pinion gear and the final spur gear has a shaft thereof mounted in one-piece cylindrical bushings formed integrally in opposite walls of the gearbox.

Preferably each said gear and its said shaft comprises a one-piece plastics moulding Preferably said opposite walls of the gear box are respective parts of a two-part gear box housing interconnected in a plane perpendicular to the said axle shaft(s).

An embodiment of the invention will now be described by way of example and with reference to the accompanying drawings in which.

Figure 1 is a partial axial cross-sectional view of the relevant parts of a known toy vehicle; Figure 2 is a detail at A of Figure 1; Figure 3 is a similar view of the relevant parts of a toy vehicle according to the invention; and Figure 4 is a more detailed and exploded view of the apparatus of Figure 3.

Referring first to Figure 1, a known toy vehicle includes a gear box 1 housing an electric motor 2 whose drive shaft 3 extends parallel to the length of the vehicle and thus perpendicular to a wheel axle shaft 4 journalled in a recess in the floor of the gear box 1. The motor shaft 3 drives a reduction gear train comprising a pinion gear 5, a spur gear 6, a worm 7 and. a worm gear 8 secured on the axle shaft 4.The gear box casing comprises upper and lower shells 9 and 10 joined together in a horizontal plane 11 (Figure 2) and the shaft 12 of the worm 7 is mounted in a cutout 13 in the front wall of the lower shell 10 of the gear box, with the result that if the vertical dimension of the cut-out 1 3 is slightly less than the diameter of the shaft 1 2 then rotation of the shaft is obstructed by frictional forces and power is lost, whilst if the said dimension is greater than the diameter of the shaft then the resulting looseness leads to noisy operation.

Referring now to Figure 3, a toy vehicle according to the invention has a gear box 20 housing an electric motor 21 having forwardly and rearwardly extending drive shafts 22 and 23 both perpendicular to a wheel axle shaft 24. A reduction gear train between the motor and the axle shaft comprises a pinion gear 25, a crown gear 26, and a series of five spur gears 27 to 31 leading to a final spur gear 32 secured on the axle shaft 24.

Referring now to Figure 4 which shows the embodiment of the present invention in more detail, it will be seen that the reduction gear train just described is duplicated between the respective forwardly and rearwardly extending motor shafts 22 and 23 and front and rear wheel axles 24 and 33. The gear box comprises two opposite and similar shells 34 and 35 arranged to be joined together in a vertical plane perpendicular to the axes of the axle shafts, the opposite side walls of which shells integrally incorporate unitary cylindrical bushings 36 for all of the gears of the two reduction gear trains other than the pinion gears 25 and the final spur gears 32.

It will thus be seen that, at least in its preferred and illustrated embodiment, the invention provides a toy vehicle which can be pushed along the ground without locking of, and consequent wear on, the drive gear train, and furthermore in which the bushings for the gear shafts are no longer such as to cause loss of power or noisy running. A further advnatage of the ability of the drive gear train to be driven in reverse when the vehicle is pushed as aforesaid is that the resulting rotation of the motor causes it to act as a generator to energise ancillary electrical equipment of the toy vehicle, such as lights.

Claims (7)

1. A toy vehicle having an electric motor arranged to drive at least one wheel axle shaft thereof, the motor shaft being perpendicular to the axle shaft, and a reduction gear train between the motor shaft and the axle shaft, said reduction gear train consisting only of a crown gear and pinion gear combination and a plurality of spur gears, the final spur gear being secured on the axle shaft.

2. A toy vehicle as claimed in claim 1, wherein the said pinion gear is secured on the motor shaft.

3. A toy vehicle as claimed in claim 1 or 2, wherein the motor has a said shaft extending both forwardly and rearwardly therefrom, there being a said reduction gear train between each said motor shaft and a front and rear wheel axle shaft respectively, to provide four-wheel drive.

4. A toy vehicle as claimed in any of the preceding claims including a gear box housing the said gear train(s), each of the said gears other than the said pinion gear and the final spur gear having a shaft thereof mounted in one-piece cylindrical bushings formed integrally in opposite walls of the gear box.

5. A toy vehicle as claimed in claim 4, wherein - each said gear and its said shaft comprises a onepiece plastics moulding.

6. A toy vehicle as claimed in claim 4 or 5, wherein said opposite walls of the gear box are respective parts of a two-part gear box housing interconnected in a plane perpendiuclar to the said axle shaft(s).

7. A toy vehicle as claimed in claim 1, substantially as hereinbefore described with reference to the accompanying drawings.