GB2131309A - Flywheel drive mechanisms, eg for toys - Google Patents

Abstract

Transmission of rotation of a flywheel 12 to a rotary body (e.g. a toy auto-cycle wheel 1) is automatically interrupted if a retarding force of the order produced by a finger touching the wheel is applied. An internal gear ratchet (14) is fixed with respect to the flywheel (12) such that it rotates in synchronism with the flywheel, and a rotatable engaging pawl (16) independent of said ratchet is housed in an inner diameter portion of the inner gear ratchet, the engaging pawl being fixed with a gear (18) coaxial with the flywheel, which gear is geared into a rotation transmission gearing 10, 8, 6, 2 for the rotary body. <IMAGE>

Description

SPECIFICATION A safety-device of a rotary mechanism with a flywheel This invention relates to a safety device of a rotary mechanism which employs a flywheel.

A toy car, for example, is rubbed with its wheels against a stationary object, e.g. a floor, to forcibly produce rotation and to transmit it to a flywheel via a group of gears. The rotation of the wheel is maintained due to the inertia of the flywheel.

The flywheel is rotated at high speed while possessing considerable energy, and if the rotating wheel is carelessly touched, the fingers would be affected by abrasion caused by the wheel rotating with powerful energy. Attention to safety devices has, therefore, been given especially for toys for children and there have been many proposals therefor.

However, previous safety device still have defects, e.g. they have rather complicated mechanisms, or a strong force is partially biased to renderthe mechanism breakable, or a comparatively large force is required to stop rotation of the wheels.

The invention provides a safety device of a rotary mechanism having a flywheel, for transmitting rotation of the flywheel to a rotary body through a gear train, comprising an internal ratchet gear associated with the flywheel so as to rotate in synchronism therewith; an engaging pawl which is mounted within said ratchet gear and is rotatable indepen dentlyofsaid ratchet gear; a gear mounted coaxial with said flywheel on said engaging pawl, and a gearing for transmitting rotational motion between said rotary body and said gear associated with said pawl.

An advantage of the invention is that it makes it possible to provide a safety device which makes it possible to instantly release transmission of rotation produced by the flywheel and stop the rotary body with minor force when the fingers touch a rotary body, such as a rotating wheel of a toy.

The invention also makes it possible to provide a safety device wbich is simple in structure and is not broken easily.

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 schematic view showing an embodiment of the invention, Figure 2 is a plan view, partly in section, of the embodiment, Figure 3 is a left side view, partly in section, of the embodiment, Figure 4 is a plan view of a flywheel, partly in section, of the embodiment, Figure 5is a plan view of a ratchet housing therein an engaging pawl, and Figure 6 is a cross sectional view of the ratchet.

In Figures 1 and 2, the reference numeral 1 designates a rotary body, which is coaxially fixed with a 1st gear 2, and rotatably mounted between side walls 4 and 5 of the device. The numeral 6 designates a 2nd gear which is an idler and is rotatably mounted on a shaft 7 fixed to the side wall 5 and meshes, as shown in Figure 1, with the 1st gear 2 and a 3rd gear 8.

The 3rd gear 8 comprises a spur gear 8a and a rod-like gear 8b integral with the gear 8a, and is rotatably mounted between the side walls 4 and 5 via a pin or shaft 9 running therethrough. The rod-like gear 8b meshes with the 2nd gear 6.

Numeral 10 designates a 4th gear which, as shown also in Figure 3, comprises a large diameter spur gear 10a and a smaller diameter spur gear 10b, and is rotatably mounted on the side wall 4 via a pin 11, while the smaller diameter spur gear 10b meshes with the spur gear 8a of the 3rd gear 8. Each of the above mentioned gears in the present embodiment are made of a hard synthetic resin.

Numeral 12 designates a flywheel which, as seen in Figure 4, comprises a disc 1 2a and a outer ring 12b fitting the disc 12a, and is defined with a plurality of small diameter holes 13 equiangularly spaced therearound. The flywheel 12 is made of iron in this embodiment, whereas it was die-cast in prior art constructions.

The flywheel 12 is, as in Figures 5 and 6, provided with a ratchet 14 which is equal, in outer diameter, to the flywheel 12 in the present embodiment, and is formed with a plurality of teeth 20 on its inner circumference. Further, projections 15 are provided at positions corresponding to said small diameter holes 13, and the projections 15 are inserted into the holes 13 so that the ratchet 14 is attached with respect to the flywheel 12.

The ratchet 14 houses therein an engaging pawl 16 on its inner diameter part 14a. The engaging pawl 16 generally has the form of a reverse S shape in this embodiment, and is defined at its both ends with pawl portions 17 for engaging between internal teeth 20 of the ratchet 14. The engaging pawl 16 is fixed at its centre with respect to a 5th gear 18 which engages the large diameter spur gear 10a of the 4th gear 10.

The engaging pawl 16 and the 5th gear 18 are rotatably mounted on a pin 19 running through central portions thereof (see Figures 2 and 3), the pin 19 being fixed in the flywheel 12 and held between the side walls 4 and 5, whereby the engaging pawl 16 and the 5th gear 18 are rotatably independent of the flywheel 12 and the ratchet 14 mounted on the flywheel 12. The ratchet 14, the engaging pawl 16 and the gear 18 are made of a hard synthetic resin.

Said reverse S shape of the engaging pawl 16 may be replaced by a normal S shape in dependence upon the direction in which the teeth 20 of the ratchet 14 face and the rotational direction thereof.

When the ratchet is attached to the flywheel 12, it is possible that the projections 15 of the ratchet 14 are inserted into the small diameter holes 13 of the flywheel 12, and the projections 15 protruding in the opposite direction of the flywheel are expanded by heating to prevent the ratchet 14from disengaging from the flywheel 12. An attaching means for attaching the ratchet 14 to the flywheel is optional.

Modifications to the precise structures of the other members of this embodiment are of course possible in accordance with the invention as claimed in the accompanying claims, The above mentioned device is applicable to a toy auto-cycle in this embodiment, and the toy runs on a pair of back wheels of the rotary body 1 and a front wheel 21 as shown in Figure 2. However a mechanism according to the invention may be applied to a rotary mechanism where a flywheel is utilized in other fields.

In accordance with the present embodiment as described above, when the rotary body 1 is forcibly rotated by rubbing it against a stationary object, rotation is generated in the 1 sot gear 2, the 2nd gear 6, the 3rd gear 8 and the 4th gear 10, and the 5th gear 18 fixed to the engaging pawl 16 is rotated. The engaging pawl 16 is caused to rotate in a direction opposite to that in which the teeth 20 of the ratchet 14 face, and the pawl portions 17 are engaged between the ratchet teeth 10, so that the rotation of the gear 18 is transmitted to the flywheel 12, which is rotated.

When the flywheel 12 is thus rotated, the rotation is transmitted to the rotary body 1 via each of the gears due to the inertia of the flywheel.

However, while the rotary body is rotated at high speed, and if any resistance is given to the rotary body, e.g. by a finger, the resistance being added to the rotation of the gears and the engaging pawl 16, only the flywheel 12 is released from the engaging relation with the pawl portion 17 of the engaging pawl 16, and only it continues to rotate. Therefore since rotation of the flywheel 12 is then not transmitted to any of the gears or the rotary body 1, the rotary body 1 is stopped by a comparatively low force.

As described above, if a finger touches the rotary body, such as the rotating wheels, in the rotating mechanism employing the flywheel, and since transmission of the rotating force from the flywheel is instantly interrupted, the finger is protected from skin abrasion. Since rotation oftheflywheel is transmitted to the other gears by gearing between the gear formed on the inner circumference of the flywheel 12 and the engaging pawl attached within the flywheel, the rotating force of the flywheel can be transmitted to the gear group efficiently, and in addition this transmission may be released from the flywheel by a comparatively low force. Further, the structure is relatively simple such that large forces are not imposed on the structural members and disadvantageous disorders may be reduced.

Claims (1)

1. Asafety device of a rotary mechanism having a flywheel, for transmitting rotation of the flywheel to a rotary body through a gear train, comprising an internal ratchet gear associated with the flywheel so as to rotate in synchronism therewith; an engaging pawl which is mounted within said ratchet gear and is rotatable independently of said ratchet gear; a gear mounted coaxial with said flywheel on said engaging pawl, and a gearing for transmitting rotational motion between said rotary body and said gear associated with said pawl.

2. A device as claimed in Claim 1, comprising a plurality of small diameter holes formed at equiangularly spaced positions around the flywheel, and projections at corresponding positions on said ratchet gear, said projections being received in the corresponding holes in the flywheel so that the ratchet gear is attached with respect to the flywheel.

3. A device as claimed in Claim 1 or Claim 2, wherein the engaging pawl has the form of a reverse S shape or a normal S shape.

4. A device as claimed in any preceding Claim, wherein said engaging pawl, which is housed within said ratchet gear, and said gear fixed with respect to said engaging pawl are rotatably mounted on a pin secured to the flywheel.

5. A device as claimed in any preceding Claim, wherein the flywheel is made of iron.

6. A device as claimed in any preceding Claim, wherein said gearing comprises a 1st gear for rotation with said rotary body, a 2nd gear which is an idler gear and meshes with said 1 st gear, a 3rd gear which is a spur gear and a rod-like gear integral with the spur gear, the rod-like gear meshing with the 2nd gear, and a 4th gear which comprises a larger diameter spur gear and a smaller diameter spur gear, the smaller diameter spur gear meshing with said 3rd gear and the larger diameter spur gear meshing with a gear fixed with respect to the engaging pawl.

7. A safety device of a rotary mechanism having a flywheel, substantially as herein before described with reference to, and as illustrated in, the accompanying drawings.

Superseded claims 1 and 6 New or amended claims:

1. A safety device of a rotary mechanism having a flywheel, for transmitting rotation of the flywheel to a rotary body through a gear train, comprising an internal ratchet gear associated with the flywheel so as to rotate in synchronism therewith; an engaging pawl which is mounted within said ratchet gear and is rotatable independently of said ratchet gear; a gear mounted coaxial with said flywheel on said engaging pawl, and a gearing for transmitting rotational motion between said rotary body and said gear associated with said pawl, said gearing comprising a first gear for rotation with said rotary body, a second gear which is an idler gear and meshes with said first gear, a third gear which is a spur gear and a rod-like gear integral with the spur gear, and a fourth gear which comprises a larger diameter spur gear and a smaller diameter spur gear, the smaller diameter spur gear meshing with said third gear and the larger diameter spur gear meshing with a gear fixed with respect to an engaging pawl.