GB2046602A

GB2046602A - A motor for a toy car

Info

Publication number: GB2046602A
Application number: GB7913818A
Authority: GB
Original assignee: LUCKY PLASTIC FACTORY Ltd
Current assignee: LUCKY PLASTIC FACTORY Ltd
Priority date: 1979-04-20
Filing date: 1979-04-20
Publication date: 1980-11-19
Also published as: HK40484A; GB2046602B

Abstract

In a toy car, a motor 3 is mechanically connected to road wheels 12 so as to rotate the wheels 12 and be rotated thereby. The motor 3 is electrically connected to terminals 4, 5 for receiving electrical power, for instance from a battery. The motor 3 has rotational states of equilibrium by having a commutator with two conductive portions and two insulated portions, so that it starts to rotate under power when the wheels 12 are rotated by pushing the car along the ground, but stops in one of its equilibrium states when the wheels 12 are stopped, such as when the car runs into an obstruction. <IMAGE>

Description

SPECIFICATION Improvements in or relating to toy cars and gearboxes therefor The present invention relates to toy cars and geartoxes therefor.

According to one aspect of the invention, there is provided a toy car comprising a two-pole motor ^mechanically connected to at least one road wheel of the car and electrically connected to terminals for connection to a source of electrical power, the motor having rotational states of equilibrium.

The motor may thus be connected directly and without any form of switch to a source of power such as a dry cell or battery. With the motor in any of its states of equilibrium, the motor thereof will remain stationary. However, by rotating the road wheel or wheels connected to the motor, for instance by pushing the car along a floor, the rotor will start to rotate under power and will drive the car. If the car runs into an obstruction so that the road wheels are stopped, the increased load on the motor will cause it to stop in one of its rotational equilibrium states. The toy car thus has a built-in automatic stop/push-start system.

According to another aspect of the invention, there is provided a gearbox for a toy car, comprising a first gear wheel mounted on the rotor of a motor, a sec ond gear wheel mounted on a wheel shaft of the car, and an intermediate shaft having third and fourth gear wheels in mesh with the first and second gear wheels, respectively, so as to form a two-stage reduction drive from the motor to the wheel shaft.

This gearbox provides a relatively simple arrangement suitable for toy cars.

The invention will be further described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a plan view of part of a toy car constituting a preferred embodiment of the invention; Figure 2 is a longitudinal cross-section of a motor of the toy car of Figure 1; and Figure 3 is a transverse cross-section of the motor of Figure 2.

The toy car shown in Figure 1 comprises a chassis 1 including a box-like portion 2 for containing two dry cells. These are provided contacts (not shown) in the box-like portion 2 arranged so that the two dry cells are connected in series and to a motor 3 via conductive leads 4 and 5. The conductive leads 4 and 5 are made of a resilient metal such as phosphor bronze and form a unit with the motor 3, which unit is fitted into the chassis 1 by sliding so that a bushing 6 of the motor and a bushing 7 on the lead 5 are push-fitted into slots at either side of the chassis with the contact ends of the leads 4 and 5 entering the portion 2 through apertures 8 and 9.

The motor 3 has an output shaft 10 on which is mounted a first gear wheel 11 made, for instance, of nylon. Two road wheels 12 of the toy car are mounted on a wheel shaft 13 which is rotatably mounted in the chassis 1. Bushings 14 and 15 are fixed to or integral with the chassis 1 and, together with washers 16 and a second gear wheel 17, determine the axial position of the shaft 13. Between the first and second gear wheels 11 and 17, there is provided a protuberance 18 fixed to or integral with the chassis 1. An intermediate shaft 19 is fixed in the protuberance 18 and rotatably supports third and fourth gear wheels 20 and 21, respectively, which mesh with the first and second- gear wheels 11 and 17, respectively.

The motor 3 is a two-pole motor and comprises a housing 22 with an end bell 23. The shaft 10 is rotatably supported in bearings 24 and 25 of the housing 22 and the end bell 23, respectively. A fixed permanent magnet forming a stata of the motor 3 has poles 26 and 27 fixed to the housing 22 and surrounding a rotor of the motor.

The rotor includes the shaft 10 and a two-pole core 28 on which are provided windings 29 and 30. One end of each of the windings 29 and 30 is connected to a respective one of two conductive portions 31 (only one of which is shown) of a commutator32.

The other end of each of the windings 29 and 30 is connected to the housing 22, which is made of metal, via the shaft 10, which is also made of metal.

A contact 33 serves to connect one pole of a power supply to the housing 22 and then to the windings 29 and 30. A brush 34 is mounted at one end in the end bell 23. The one end is connected to a terminal 35 for providing a connection to another pole of the power supply. The other end of the brush 34 is urged against the commutator 32 so as to provide a connection with the windings 29 and 30 when either of the conductive portions 31 is in contact with the brush.

The terminal 33 is extended around the motor 3 and constitutes the lead 5 whereas the terminal 35 is bent around to constitute the lead 4.

When pen dry cells are installed in the portion 2 of the chassis 1 of the toy car, power is supplied to the motor via the leads 4 and 5 directly from the dry cells. When the rotor of the motor 3 is in a position such that an insulated portion of the commutator is in contact with the brush 34, the windings 29 and 30 are disconnected from the terminal 35 so that no circuit is formed and no current flows. The commutator 32 has two such insulated portions which define two equilibrium positions of the rotor at which the rotor remains rotationally at rest. When the road wheels 12 are rotated, for instance by pushing the car along the ground, the shaft 10 of the motor 3 is rotated via the gear wheels 11, 17,20 and 21 so that a conductive portion 31 of the commutator comes into contact with the brush 34.For as long as a conductive portion is in contact with the brush 34, current flows through one ofthewindings 29 and 30 and a motive force is applied to the rotor tending to turn it. Continuous rotation of the shaft 10 results in a series of impulses of torque being applied to the rotor. If the speed of rotation of the shaft 10 is such that the intermittent pulses of torque or not sufficient to overcome the inertia of the moving parts and of the car, then the motor will stop rapidly and remain in one of its equilibrium states. However, when the rotational speed of the shaft is sufficiently fast for each impulse of torque to maintain rotation of the rotor and to overcome the inertia and frictional forces of the moving parts and of the car, the motor drives the road wheels 12 of the car continuously until the speed of the rotor is again slowed down to a value too low for the intermittent pulses of torque to maintain rotation. Thus, no power is consumed while the rotor is in one of its equilibrium states and the car may be started by simply pushing it along the ground. When the road wheels are slowed down sufficiently or stopped, for instance when the car runs into an object, the motor automatically switches off and no current is drawn from the dry cells. This system therefore dispenses with the need to provide any sort of on-off switch connected in circuit with the motor and the dry cells.

Claims

1. A toy car comprising a motor mechanically connected to at least one road wheel of the car and electrically connected to terminals for connection to a source of electrical power, the motor having rotational states of equilibrium.

2. A toy car as claimed in Claim 1, in which the motor includes a rotor having windings and a commutator which cooperates with a brush for supplying electric power to the windings, the commutator having circumferentially alternate conductive and insulative portions, the insulative portions being arranged to cooperate with the brush to prevent the supply of electric power to the windings.

3. Atoy car as claimed in Claim 2, in which each winding has a first end connected to a respective one of the commutator conductive portions and a second end electrically connected to a frame of the motor.

4. A toy car as claimed in any one of the preceding claims, in which the terminals comprise bent metal strips fixed to the motor so as to form a unit which is a slide fit in a chassis of the toy car.

5. A toy car substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

6. A gearbox for a toy car, comprising a first gear wheel mounted on the rotor of a motor, a second gear wheel mounted on a wheel shaft of the car, and an intermediate shaft having third and fourth gear wheels in mesh with the first and second gear wheels, respectively, so as to form a two stage reduction drive from the motor to the wheel shaft.