WO1988007397A1

WO1988007397A1 - Torsion spring drive for toys

Info

Publication number: WO1988007397A1
Application number: PCT/DK1988/000053
Authority: WO
Inventors: Lars RINGSTRÖM
Original assignee: Ringstroem Lars
Priority date: 1987-04-02
Filing date: 1988-03-30
Publication date: 1988-10-06
Also published as: DK167887A; DK167887D0

Abstract

Torsion spring drive for toys, with a spring (2) of rubber or similar elastomeric material, wherein the spring (2) is a massive body whose largest inscribable cylinder has a ratio between the diameter and the length of between 0.2 and 2. The spring (2) has a circular cross-section along most of its length, and may in particular be hour-glass shaped. The drive is particularly used with a transmission (4, 7, 9, 10) for translating the relatively small angular travel of the spring into a number of rotations or into a linear movement. There is shown a gear wheel drive (4, 7, 9, 10), a rack-and-pinion drive and a lever drive. For regulating the runoff speed there is used a flywheel or a speed regulator. There are shown various toy models, amongst others a toy boat with a liquid exhauster drive.

Description

Torsion spring drive for toys

The invention relates to a torsion spring drive for toys, with a spring of rubber or a similar elastomeric material.

In presently known torsion spring drives for toys, for example for toy cars, toy airplanes etc. it is usually a rubber band which is used as a spring. The band is- extende between a fixture on the toy and a rotatable toy part, for example a propeller. The band is then twisted by manually- turning the propeller whereby the band is both longitudi¬ nally stretched and torsionally loaded. When the propeller is released, the band seeks to spring back to its original shape and thereby turns the toy element involved, for ex- ample the propeller.

Seen in relation to this known technique it is the task of the invention to provide a torsion spring drive which can be contained in a smaller volume than the known rubber band drives without necessarily having less energy storage capa¬ city.

In a torsion spring drive of the kind mentioned initially, wherein the spring consists of rubber or a similar elasto- meric material, this task is accomplished according to the invention by constructing the drive with the characteristic features presented in patent claim 1.

In the drive according to the invention the spring is a massive body whose largest inscribable cylinder has a dia¬ meter to length ratio between 0.2 and 2. Thus the spring is a true torsion spring which approximately has the shape of a rod (larger length than diameter), of a block (approxima¬ tely equal length and diameter) or of a relatively thick disc (smaller length than diameter). The strength of the spring (the spring coefficient) depends on the material properties and the shape of the spring and can therefore be adjusted between wide limits. In the tor¬ sion of such a relatively compact, massive spring an equal amount of energy can be stored in a smaller volume than by twisting the presently known spring bands, because the energy stored in the massive torsion spring is distributed across a larger cross-section than in the bands.

The embodiment of the spring presented in claim 2 is advan¬ tageous in the manufacture. The shape presented in claim 3 gives the spring a particularly soft torsional characteri¬ stic which is pleasant in use. The shape furthermore gives larger end surfaces for a given elasticity than a cylindri- cal spring and therefore eases the mounting.

A special feature of the drive according to the invention is the fact that for a given stored energy the torsion spring drive will provide subtantially less angular travel than a twisted band. Because of this the embodiment of the drive as presented in claim 4 is preferred where a use as a toy motor is concerned, as the transmission can be used to increase the angular travel at correspondingly decreased angular moment. Other applications may be thought of, how- ever, where a transmission is not needed, for example the tipping of the platform on a dumper truck model or other movements of function elements of toy models.

The embodiments of the transmission presented in claims 5 and 6 are preferred because they may be adapted to the dri¬ ve according to the invention very easily. The first driven wheel in the transmission can be mounted directly on the spring, as it may for example be an extension thereof or be formed on the outer surface of a casing which is connected with and surrounds the spring. To avoid that the drive according to the invention runs too fast one may advantageously use a flywheel in the transmis¬ sion, as provided for in claim 7, or a speed regulator as presented in claim 8. The speed regulator may be an escape- ment of the kind well-known in clockworks. The use of a flywheel leads to a slow start of the movement and to a certain continuation of the movement after the relaxation of the spring, and in toys this can give a movement charac¬ teristic which looks very realistic and much like the move- ment characteristic of hydraulic mechanisms.

As presented in claim 9 protection is sought for any kind of toy wherein a torsion spring drive according to the in¬ vention is used. The use in a toy boat of the kind defined in claim 10 is particularly advantageous because the sy¬ ringe presents a. relatively large resistance to the drive such that a natural slowing down of the movement characte¬ ristic is attained. Therefore the propulsion of the boat may be of a rather long duration.

The invention will be described more specifically in the following with reference to the accompanying drawings, wherein

Fig. 1A shows a torsion spring drive according to the invention as seen from above,

Fig . IB show the same torsion drive in a side view,

Fig . 2 shows a torsion drive with a flywheel,

Fig . 3A shows a torsion drive with a gear rack as seen from above,

Fig. 3B shows the torsion drive with the gear rack in a side view, Fig. 4A shows a torsion drive wherein the winding and the power take-off happen at opposite ends of the spring,

Fig. 4B shows the stopping mechanism which is used on the winding side in the torsion drive shown in fig. 4A,

Fig. 5A shows a torsion drive with a lever for power take-off as seen from above, Fig. 5B shows the torsion drive with the lever for po¬ wer take-off in a side view,

Fig. 6A shows a toy boat which is propelled by a sy¬ ringe which exhausts below the waterline and which is driven by a torsion drive, Fig. 6B shows a boat with a syringe drive wherein the driving force is transmitted from a torsion drive via a knee link,

Fig. 7 shows a toy model of a front loader,

Fig. 8 shows a toy model of a dumper truck, Fig. 9 shows a toy model of a fork lift,

Fig. 10 shows another embodiment of a toy dumper truck, and

Fig. 11 shows another embodiment of a toy fork lift.

The torsion drive shown in fig. 1 consists of a U-profile 1 wherein there is mounted an hourglass-shaped torsion spring 2 consisting of rubber or an other elastomeric material. An end of the rubber body 2 is glued to one leg of the U-pro¬ file at 3 while the other end is glued to a gear wheel 4 4 carrying an axle 5 which extends through the other leg of the U-profile. The end of the axle is provided with a square end 6 which can be used to tension the spring 2 by means of a square key (not shown) of the commonly known kind.

The gear wheel 4 drives a smaller gear wheel 7 which in turn via an axle 8 drives a larger gear wheel 9. The latter meshes with a smaller gear wheel 10 on the exit axle 11. All the mentioned gear wheels/axles are journaled in the U- profile and only shown schematically. With the construction shown one attains a translation of the torsion of the rub- ber body, which normally is limited to one-half or a full turn, into a larger number of revolutions. Consequently the construction is well suited for use as a toy motor. Because of the shortness of the torsion spring this toy motor may be made with miniaturized dimensions.

Fig. IB shows in a side view the arrangement of the gear wheels in relation to the torsion spring 2.

In fig. 2 there is seen a similar drive as in fig. 1 but in this case a heavy flywheel 12 is mounted on the exit axle. Because of the inertia of this flywheel the drive will start slowly and continue moving a little when the rubber spring 2 is turned back to its relaxed position. This pat- tern of movement reflects itself in the movement of the toy parts which are driven by the drive. Amongst other things this can be exploited to give natural-looking imitations of hydrauliσally moved mechanisms such as, for example, crane arms .

A torsion drive with a power take-off via a gear rack is seen in fig. 3A and 3B. In this instance the gear wheel 4, which is glued onto the end of the hourglass-shaped rubber body 2, meshes with a gear rack 13 which slides in a guide on the bottom of the U-profile 1. The guide is not shown in any detail. This construction provides a very simple trans¬ lation of the torsion of the rubber body into a linear movement, and because of the direct drive the gear rack 13 can exert relatively large forces. Of course a gear wheel transmission could also be inserted between the gear wheel 4 and the gear rack 13 if the latter were to have a longer path of travel than permitted by the construction shown in fig. 3A and 3B.

It may be desirable in certain occasions that the ten- sioning or winding movement can be executed without thereby starting any movement of the other parts of the toy which is equipped with the drive. A possibility for attaining this is shown in fig. 4A and 4B. In this construction the winding and the power take-off are situated at opposite ends of the rubber spring.

Fig. 4A shows the drive in section along the line IV-IV shown in fig. 4b. In the operation of winding the winding wheel 14 is turned clockwise by means of a finger grip 21, as shown at 15 in fig. 4B. Provided that the power take-off from the rubber body is blocked, the cylindric rubber body is tensioned hereby. If the drive is used for driving the wheels of a toy car one may for example hold the wheels blocked. The winding wheel 14 is arrested in its tensioned position by two counterhooks 18 which engage an external toothing 19 on the winding wheel. The counterhooks 18 may for example be extended from a ring 20 which surrounds the winding wheel 14 and which may be injection-moulded from plastics material.

The power take-off consists of an externally toothed casing 17 which is glued onto the other end of the rubber spring 16 and rotatably journaled in one leg of the U-profile 1. As in the drives shown in fig. 1A, IB and 2 a gear wheel transission with gear wheels 7, 9 and 10 engages the gear wheel take-off 17 of the rubber spring, thus transferring the driving force to the exit axle 11 with a certain ratio of translation.

A very simple driving mechanism is seen in figs. 5A and 5B where an hourglass-shaped rubber body is glued in between a U-profile 1 (of clear plastics material) and a metal disc 22 which is rotatably mounted in the U-profile and provided with a recess 24. A spring-loaded release lever 25 has a protrusion 26 which can engage the recess 24. The driving mechanism according to figs. 5A and 5B is wound up by turning the lever arm clockwise as shown at 32 until the protrusion 32 catches in the recess 24 because of the spring loading 28. This is accompanied by the release lever swinging counterclockwise (as shown at 30) around the axle 29. In order to start the drive one may with a finger push the release lever in the other direction (31) for the pro¬ trusion 26 to leave the recess 24, after which the lever arm 23 will turn back to its initial position as indicated with dotted lines and the arrow 27.

The very simple torsion drive shown in fig. 5A and 5B is highly suitable for automating simple movement functions of toy models of vehicles, working implements and the like. This will be explained more closely in the following. To prevent the lever arm 23 running back to its initial posi¬ tion too quickly, a flywheel or a speed regulator of the kind known from clockworks and musical boxes will eventual¬ ly have to be coupled to the driving spring 2 in a series coupling, as far as movement is concerned, with the lever arm 23 in order to obtain a slower baσkturn.

In a strongly simplified form figs. 6A and 6B show two mo¬ dels of a toy boat 30 which is propelled by a syringe 31 which is mounted below the waterline. The syringe has a sy¬ ringe chamber 32 wherein a piston 33 can be driven back and forth. During retraction of the piston water is sucked into the syringe chamber 32 through a check valve 34. During ad¬ vancement of the piston the check valve closes and the aspirated water is ejected through a nozzle 35 in a thin jet 36 whose recoil propels the boat 30.

According to fig. 6A the rack-and-pinion drive which was earlier explained in connection with figs. 3A and 3B is used for advancing the piston, the piston rod 37 being di¬ rectly connected with the gear rack 13. Fig. 6 shows an ap- plication of the lever arm drive according to figs. 5A and 5B wherein the piston rod 37 is guided in guiding rails 38 and the transmission of force from the lever arm 23 happens via two knee links 39 and 40. An extension 41 of the lever arm 23 serves to wind up the drive. In the drive according to fig. 6A a similar lever mechanism could be used for win¬ ding up.

In this functional model of a jet-propelled boat the ejec- tion resistance of the syringe mechanism serves as a natu¬ ral restraint for the movement of the drive so that a spe¬ cial braking or speed regulation of the drive will not bee necessary.

Fig. 7 shows a functional model of a front loader vehicle 50. Here it is the loading shovel 51 which is lifted by a drive of the kind shown in figs. 5A and 5B when the release lever 25 is activated. Fig. 8 shows a corresponding func¬ tional model of truck 60 with a dumper platform 61, and fig. 9 shows correspondingly a toy model of a fork lift 70 wherein the lifting fork 71, which slides in a guide 72, is moved up and down by a similar lever arm drive. In these instances one will have to provide a suitable braking of the lever arm drive, as previously discussed.

The rack-and-pinion drive shown in figs. 3A and 3B may also advantageously be used in toy vehicles which is apparent from figs. 10 and 11. In fig. 10 there is seen a truck 80 with a dumper platform 18 which is tipped over by a knee- link mechanism 82, 83, 84, 85 coupled in between the gear rack 13, the platform 81 and a point of fixation 86 on the chassis of the truck. In fig. 11 a rack-and-pinion drive is seen used in a fork lift truck 90. The gear rack 13 moves the fork 91 which slides up and down in a guide 92.

In the above description the invention has been explained by means of examples wherein the rubber spring is shown in a cylindrical or hourglass shape. The shaping of the spring may have a certain influence on its resiliency characteri¬ stic, and it has shown that in particular the hourglass shape gives a very pleasant, soft characteristic. Other shapes of the spring may also be used, however, it may be convex instead of concave, or have an elliptic or a rectan¬ gular cross section, for example, if these forms should turn out to ease the mounting or be advantageous in any specific instance of application.

To attain the advantages connected with the invention it is important, however, that the spring is relatively compact and massive. Suitable forms are believed to be such wherein there can be inscribed a largest cylinder which has a dia¬ meter to length ratio between 0.2 and 2. In any case the applicant reserves the right to make any one of the toy and toy drive embodiments shown the subject of separate patent claims.

Claims

Patent claims

1. Torsion spring drive for toys, with a spring of rubber or a similar elastomeric material, c h a r a c t e r i z e d in that the spring (2, 16) is a massive body whose largest inscribable cylinder has a dia¬ meter to length ratio between 0.2 and 2.

2. Torsion spring drive according to claim 1, c h a r a c t e r i z e d in that the spring has a circu¬ lar cross-section over most of its length.

3. Torsion spring drive according to claim 2, c h a r a c t e r i z e d in that the spring is hourglass shaped.

4. Torsion spring drive according to one of claims 1 - 3, c h a r a c t e r i z e d in that an end (3) of the spring (2) is connected with a fixed toy part (1) while the oppo- site end of the spring is connected via a transmission (4, 7, 8, 9, 10, 12, 13, 39, 40, 82, 83, 84, 85, 86) with a mo¬ vable toy part (11) which is movable in relation to the fixed toy part (1).

5. Torsion spring drive according to claim 4, c h a r a c t e r i z e d in that the transmission compri¬ ses a gear wheel drive (4, 7, 8, 9, 10, 12, 13) which is connected with the movable toy part (11).

6. Torsion spring drive according to claim 5, c h a r a c t e r i z e d in that the gear wheel drive (4, 7, 8, 9, 10, 12, 13) comprises a gear rack (13) connected with the movable toy part (11).

7. Torsion spring drive according to claim 6, c h a r a c t e r i z e d in that the gear wheel drive (4, 7. 8, 9, 10, 12, 13) comprises a flywheel (12).

8. Torsion spring drive according to claim 5 or 6, c h a r a c t e r i z e d in that the gear wheel drive (4, 7, 8, 9, 10, 12, 13) comprises a speed regulator.

9. Toy, c h a r a c t e r i z e d in that it is equipped with a torsion spring drive according to one of claims 1 - 8.

10. Toy boat, c h a r a c t e r i z e d in that it is equipped with a propelling mechanism in the nature of a syringe (31) whose discharge opening is below the waterline and whose piston (33) is driven by a torsion spring drive according to one of claims 4 - 6.