Floatable structure propelling mechanism

Abstract: A floatable structure propelling mechanism (3) is combined with a floatable structure (1) filled with helium gas to propel the floatable structure for flying in the air. The propelling mechanism (3) has a rubber cord (5) to be twisted to store driving energy. When the rubber cord (5) is untwisted, a double crankshaft (7) is caused to rotate about a crank journal (7a) whereby crank pin portions (7b, 7b') are caused to make rotary motion, which is transmitted through connecting rods (8, 9; 8', 9') to lateral fins (2). The lateral fins are pivoted by hinges (10) so that the fins are caused to reciprocatingly swing vertically as a result of the rotary motion of the crank pin portions, whereby the floatable structure (1) can fly and advance in the air.

Description: The present invention relates to a flying apparatus according to the first part of claim 1, such as a flying toy or a floatable advertising medium, indoors and outdoors. In a toy airplane of this kind as known from US-A-4 155 195 the power to be afforded by the rotary driving unit in the shape of an elastic band to be twisted by a user must be sufficient to lift and propel the body of the airplane which is heavier than air. Similar toy airplanes are known, in which the rotary driving force afforded by the twisted elastic band is also transformed to a swinging movement of the wings (US-A-4 195 438, FR-A-1 758 178). A further known model plane, i.e., one of various flying toys, employs a screw propeller for propulsion and, in general, employs a torsional driving means, such as a rubber cord, as a motive power source for rotating the screw propeller. Requiring a relatively small torque, the screw propeller is rotated at a relatively high rotational speed by the torsional driving means to generate a relatively large propulsion. When a rubber cord is used as a motive power source, however, the driving energy stored in the rubber cord by twisting the same is consumed and exhausted rapidly in a relatively short time and hence the model plane is unable to fly at a relatively low flying speed for a long time. To enable the model plane to fly for a long time, a long rubber cord or a plurality of rubber cords are used, which, however, increases the weight of the rotary driving means. Furthermore, the screw propeller rotating at a high rotational speed is dangerous in that it may possibly injure childrens. Accordingly, it is the problem of the present invention to provide an inexpensive and safe flying apparatus, the propelling mechanism of which may be made smaller as in the prior art apparatus and at the same time enables the apparatus to float in the air in a well balanced attitude at a very low flying speed for a sufficiently long time. This problem is solved by claim 1. When the double crankshift is rotated by the rotary driving unit, the lateral fins are swung alternately in opposite vertical directions, whereby the flying apparatus advances by means of reaction to the air urged backward by the lateral fins. The rotary driving unit having a motive power source, such as a rubber cord, a spiral spring or a motor, rotates the crankshaft in such a manner that said cranking motion will be converted into a reciprocal swinging movement of the forward rigid portion of the fin means, followed by a reciprocal swinging movement of the rearward resilient portion, to propel the floatable structure forward. No lifting energy has to be provided by the rotary driving unit so that energy consumption thereof is low. The above object, features and advantages of the present invention will become more apparent from the following description taken in connection with the accompanying drawings, in which: Figure 1 is a side view of a floatable structure in the form of a fish provided with a floatable structure propelling mechanism in a first embodiment according to the present invention; Figure 2 is a perspective view of an essential portion of the floatable structure propelling mechanism of Fig. 1; Figure 3 is a diagrammatic front view of an essential portion of the floatable structure propelling mechanism of Fig. 1; Figure 4 is a perspective view for an explanation of a dynamic action of a lateral fin employed in the floatable structure propelling mechanism of Fig. 1; Figure 5 is a diagrammatic view, as viewed in the direction of the arrow in FIG. 4, for explaining the dynamic action of the lateral fin when the lateral fin swings upward; Figure 6 is a diagrammatic view, as viewed in the direction of the arrow in FIG. 4, for explaining the dynamic action of the lateral fin when the lateral fin swings downward; Figure 7 is a side view of a floatable structure in the form of a fish provided with a floatable structure propelling mechanism in a second embodiment according to the present invention; Figure 8 is a diagrammatic plan view of the floatable structure propelling mechanism of Fig. 7 for explaining the operation and geometry of the floatable structure propelling mechanism in propelling the floatable structure along a curved line; Figure 9 is a diagrammatic plan view similar to Fig. 8, for explaining the operation and geometry of the floatable structure propelling mechanism in propelling the floatable structure along a straight line; Figure 10 is an enlarged side view of a rotary driving unit included in the floatable structure propelling mechanism of Fig. 7; and Figure 11 is an enlarged side view of a portion of the floatable structure propelling mechanism of Fig. 7. The present invention will now be described hereinafter as applied to a floatable structure, i.e., a flying toy resembling a fish. First Embodiment (Figs 1 to 6) Referring to Fig. 1, a floatable structure 1 is formed of a lightweight, flexible material, such as a synthetic resin film, capable of maintaining a fixed morphology in the form of a fish having a hollow structure and is provided with a floatable structure propelling mechanism 3 including a rotary driving unit 4 and lateral fins 2 resembling the pectoral fins of a fish. The floatable structure 1 is filled with a gas lighter than air, such as helium gas. The buoyancy and attitude of the floatable structure 1 is adjusted by a ballast. The floatable structure propelling mechanism 3 is attached to the lower surface of the floatable structure 1 by suitable means, such as an adhesive, with its center of gravity located on a vertical line passing through the center G of gravity of the floatable structure 1 as shown in Fig. 3. The construction of the floatable structure propelling mechanism 3 will be described hereinafter. Referring to Figs. 2 and 3, the floatable structure propelling mechanism 3 comprises a support bar 6, a hook 7a₂ attached to the rear end of the support bar 6, a double crankshaft 7 supported for rotation by a projection 6a formed at the front end of the support bar 6, and having a crank journal 7a and opposite crank pin portions 7b and 7b', a rubber cord 5 extended between the hook 7a₂ and a hook 7a₁ formed at the rear end of the crank journal 7a of the double crankshaft 7. The mechanism 3 further comprises a frame 24 consisting of opposite side members 24a and 24b and cross members 24c and 24d, and attached to the support bar 6. The lateral fins 2 are pivotally supported for swinging motion by hinges 10 on the side members 24a and 24b of the frame 24, respectively. First connecting rods 8 and 8' are pivotally joined respectively to the crank pin portions 7b and 7b' of the double crankshaft 7. Second connecting rods 9 and 9' are pivotally connected at respective one end thereof to the free ends of the first connecting rods 8 and 8' and fixedly connected at the respective other end thereof to the lateral fins 2. The cross members 24c and 24d of the frame 24 are curved so as to extend along the curved lower surface of the floatable structure 1 and are fixedly secured to the lower surface. Each hinge 10 consists of pipes 10a fixed to the lateral fin 2, pipes 10b fixed to the cross members 24c and 24d of the frame 24 coaxially with the pipes 10a, and a pin 11 passed through the pipes 10a and 10b. As shown in Fig. 4, each lateral fin 2 is formed in a substantially triangular shape tapered off toward the tip and resembling the pectoral fin of a fish, either by spreading a film 2'' on a framework 2' formed of a lightweight, flexible members, such as bamboo wires, or by molding a plastic. The framework 2' forms a part of a forward rigid portion of each fin 2. The film 2'' is spread rearward and outward slightly loosely so that portions of the lateral fin 2 near the tip and the trailing edge will increasingly flex and the lateral fin 2 may swell or become convex to produce lift and propulsion efficiently when the lateral fin 2 is swung vertically. The geometry of the floatable structure propelling mechanism 3 is determined so that the lateral fins 2 extend in a substantially horizontal neutral positions N when the double crankshaft 7 of the rotary driving unit 4 is at a neutral position as shown in Fig. 3. When the double crankshaft 7 is rotated as a result of untwisting of the twisted rubber cord 5, the double crankshaft 7 is rotated, and the cranking motions of the crank pin portions 7b and 7b' are transmitted through the connecting rods 8, 9, 8' and 9' to the lateral fins 2, whereby the lateral fins 2 are caused to swing about the hinges 10 alternately up and down with respect to the neutral positions N. The floatable structure propelling mechanism 3 is assembled beforehand and the same is incorporated into the floatable structure 1 by attaching the frame 24 to the floatable structure 1 by suitable means, such as an adhesive. When the floatable structure 1 is released into the air after fully twisting the rubber cord 5 to store sufficient energy, the floatable structure 1 filled with helium gas floats in the air and is propelled by the propulsion of the lateral fins 2 being swung alternately up and down by the double crankshaft 7. The weight and disposition of the ballast is adjusted properly so that the floatable structure floats in the air in a balanced attitude and turns in a desired direction. The dynamic performance of the lateral fins 2 will be described hereinafter with reference to Figs. 4 to 6. During the upward swing of each lateral fin 2 from the lower limit position A through the neutral position N to the upper limit position B, the lateral fin 2 is bent in an upwardly convex curve as shown in Fig. 5 by the resistance of air represented by a force V acting perpendicularly to the surface of the lateral fin 2. The horizontal component T of the force V thrusts the floatable structure 1 forward, that is, to the left in Fig. 5 and the vertical component L of the force V depresses the floatable structure 1. During the downward swing of each lateral fin 2 from the upper limit position B through the neutral position to the lower limit position A, the lateral fin 2 is bent in an downwardly convex curve as shown in Fig. 6 by the resistance of air represented by a force V₁ acting perpendicularly to the surface of the lateral fin 2. The horizontal component T₁ of the force V₁ thrusts the floatable structure 1 forward, that is, to the left in Fig. 6 and the vertical component L₁ lifts up the floatable structure 1. The swinging speed of the lateral fin 2 is higher in downward swing than in upward swing because the downward swing of the lateral fin 2 is assisted by the gravity of the lateral fin 2. The absolute values of the forces acting on the lateral fin 2 meet the following inequalities. V < V₁ T < T₁ L < L₁ Since L₁ > L, the floatable structure 1 can be advanced and lifted when the lateral fins 2 are swung by the rotary driving unit 4 even if the total weight of the floatable structure 1 and the floatable structure propelling mechanism 3, and the buoyancy of the helium gas are determined such that the floatable structure 1 may fall gradually while the lateral fins 2 are stopped. Both the components T and T₁ act as a thrust. When the area of the lateral fins 2 is fixed, the components T and T₁ acting as a thrust is proportional to the force V, which can be increased by increasing the angular range of swinging motion of the lateral fins 2. Thus, the lateral fins 2 are driven efficiently for swinging motion about the hinges 10 through the double crankshaft 7, the first connecting rods 8 and 8' and the second connecting rods 9 and 9' by the energy stored in the twisted rubber cord 5, so that the floatable structure 1 is able to fly slowly for a long time. The rubber cord 5 may be replaced by a motor, a spiral spring, a miniature engine or any suitable rotary driving means. When the floatable structure 1 is provided with a floatable structure propelling mechanism employing a miniature engine, the floatable structure 1 may be provided with a radio receiver to control the miniature engine by means of a radio transmitter for the remote control of the floatable structure 1. The floatable structure propelling mechanism may be provided with a plurality of pairs of lateral fins. Second Embodiment (Figs. 7 to 11) Referring to Fig. 7, a floatable structure 1 is formed of a lightweight, flexible material, such as a synthetic resin film, capable of maintaining a fixed morphology in the form of a fish having a hollow structure. The floatable structure 1 is filled with a gas lighter than air, such as helium gas, and is provided with a trapezoidal vertical fin 2A resembling the caudal fin of a fish, formed by spreading a film 2''A on a framework 2'A formed of lightweight, flexible members, such as bamboo wires, or formed by molding a plastic. The vertical fin 2A is supported for swinging motion on the rear end of the floatable structure 1 by support members 30. Each support member 30 is a soft, flexible, thin plastic strip having one end attached adhesively to the rear end of the floatable structure 1 and the other end attached adhesively to the framework 2'A of the vertical fin 2A. The vertical fin 2A may be supported for swinging motion on the floatable structure 1 by a conventional hinge or the like. When the vertical fin 2A is formed of a plastic film integrally with the floatable structure 1, the support members 30 may be omitted. As shown in Fig. 11, the axis of swinging motion of the vertical fin 2 is tilted toward the fore side at an angle ϑ to a vertical reference line H so that the floatable structure 1 is propelled slightly upward. Referring to Figs. 7, 10 and 11, a floatable structure propelling mechanism 3A of the present invention has a rotary driving unit 4A. The rotary driving unit 4A comprises a support rod 6A attached to the lower surface of the floatable structure 1, a hook 7a₂ fixed to the front end of the support rod 6A, a drive shaft 20 journaled in a bearing member fixed to the rear end of the support rod 6A and provided with a hook 20a at its front end, a rubber cord 5, i.e., a motive power source, extended between the hooks 7a₂ and 20a, a first crankshaft 7₁ formed by bending a wire, having a crank journal portion supported in bearings 14a and 14b attached to a support plate 15 extending rearward from the bearing member, a crown gear 22 fixed to the rear end of the drive shaft 20, and a pinion 23 mounted on the upper end of the journal portion of the crankshaft 7₁ in mesh with the crown gear 22. The crown gear 22 and the pinion 23 forms a gearing for increasing the rotational speed of the crankshaft 7₁ relative to that of the drive shaft 20 but decreasing the torque of the crankshaft 7₁, realtive to that of the drive shaft 20. Accordingly, a relatively large load torque acts on the crown gear 22 due to a large aerodynamic resistance to the swinging motion of the vertical fin 2A, so that the crown gear 22 and hence the drive shaft 20 are unable to rotate at a relatively high rotational speed. Consequently, the rubber cord 5 twisted to store energy is unable to be untwisted rapidly, so that the energy stored in the twisted rubber cord 5 is consumed gradually to drive the crankshaft 7₁ for a relatively long time. The crown gear 22 and the pinion 23 may be replaced by bevel gears. The crank pin portion of the first crankshaft 7₁ is connected to a crank pin portion 7a₂ of second crankshaft 7₂ formed by bending a wire and having a crank journal portion fixedly secured to a base member of the framework 2'A of the vertical fin 2A through a connecting rod 26 having one end provided with an eyebars 26a engaging the crank pin portion of the first crankshaft 7₁ and the other end provided with and eyebar 26b engaging the crank pin portion 7a₁ of the second crankshaft 7₂. The connecting rod 26 may be made adjustable in length. As shown, the crank throw of the second crankshaft 7₂ is greater than that of the first crankshaft 7₁. In Fig. 7, indicated at 27a, 27b, 28a and 28b are stoppers for the eyebars 26a, 26b. Referring to Fig. 8, when the first crankshaft 7₁ is rotated about an axis 0 in the direction of the arrow shown, the connecting rod 26 is reciprocated longitudinally to turn the crank arm portion of the second crankshaft 7₂ alternately in opposite directions in an angular range and, consequently, the vertical fin 2A is caused to swing alternately in opposite directions in an angular range, because the crank throw of the second crankshaft 7₂ is greater than that of the first crankshaft 7₁. When the floatable structure 1 is released into the air after fully twisting the rubber cord 5 to store sufficient energy, the floatable structure 1 filled with helium gas floats in the air and is propelled by the propulsion of the vertical fin 2A being swung alternately in opposite directions through the crown gear 22, the drive shaft 2o, the first crankshaft 7₁, and the connecting rod 26, the second crankshaft 7₂ by the rubber cord 5. The floatable structure 1 may be maintained in a balanced attitude by a ballast. Since the axis of swing motion of the vertical fin 2A is tilted toward the fore side at an angle ϑ to the vertical reference line H, the floatable structure 1 is propelled substantially horizontally or slightly upward, so that the floatable structure 1 is able to fly in the air. When the length ℓ of the connecting rod 26 is adjusted so that the crank pin portion 7b₁ of the first crankshaft 7₁ and the crank pin portion 7a2 of the second crankshaft 7₂ are located as shown in Fig. 9 in an initial state where the crank angle of the crankshaft 7₁ is zero, the vertical fin 2 is swung alternately in opposite directions through equal angles with respect to a central vertical plane of symmetry of the floatable structure 1 including the axis 0 of the first crankshaft 7₁ and the axis 0' of the second crankshaft 7₂ and hence the floatable structure 1 flies substantially along a straight line. On the other hand, when the length of the connecting rod 6 is increased to ℓ + α so that the center of swing motion of the vertical fin 2 is biased to the starboard as shown in Fig. 8, the floatable structure 1 can be propelled clockwise and, when the length of the connecting rod 26 is adjusted to ℓ - α, the floatable structure 1 can be propelled counterclockwise. The rubber cord 5 employed as the motive power source of the rotative driving unit 4A may be replaced by a spiral spring or a motor. The floatable structure propelling mechanism 3A shown in Figs. 8 and 9 may be formed in a mirror-image geometry with respect to the fore-to-aft centerline. The vertical fin 2A may be replaced by a horizontal fin and the arrangement of the rotative driving unit 4A may be changed accordingly. The floatable structure 1 may be provided with a plurality of propelling fins. The floatable structure propelling mechanism according to this embodiment may be applied to a floatable structure to be propelled in water.

Claims: A floatable structure propelling mechanism which comprises: a pair of lateral fins (2) hinged to a floatable structure (1) each having a forward rigid portion (2') and a rearward flexible portion and pivotally attached to said floatable structure (1) for vertical swinging movement relative to said floatable structure (1), said lateral fins (2) being made increasingly flexible toward their outer tips; and a rotary driving unit (4) supported by said floatable structure (1) and including a rotary drive source (5), a crankshaft mechanism (7) driven by the drive source to produce a cranking motion, and connecting rod means (8, 9, 8', 9') coupling the crankshaft mechnism with the forward rigid portions (2') of the lateral fins in such a manner that said cranking motion will be converted into a reciprocal swinging movement of the forward rigid portions of the lateral fins, followed by reciprocal swinging movement of the rearward flexible portions, to propel said floatable structure forward; characterized in that the floatable body (1) is hollow and is filled with a gas lighter than air. A floatable structure propelling mechanism according to claim 1, characterized in that said forward rigid portion (2') of each of the lateral fins (2) is made more slender towards its outer tip so that the forward rigid portion is increasingly flexible toward the outer tip. A floatable structure propelling mechanism according to claim 1 or 2, characterized in that said forward rigid portion (2') is curved rearwardly and extends to a rear trailing edge of said rearward flexible portion. A floatable structure propelling mechanism according to claim 3, characterized in that the gas is helium.

Inventors: KINOSHITA KOICHI C O JAL DATA, KINOSHITA, KOICHI, C/O JAL DATA COMMUN. & SYS., Kinoshita, Koichi, c/o JAL DATA COMMUN. &amp; SYS.
Applicants: JAL DATA COMMUNICATIONS & SYST, JAL DATA COMMUNICATIONS & SYSTEMS CO., LTD.
Application year: 1991
Main classification: A63H29
IPC codes: A63H23, A63H29