Electrically-operated mobile model toy
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an electrically-operated mobile model toy, more particularly an electrically-operated model car with a radio control, wherein an imitation sound generator and a start control device are provided so that the imitation sound generator can produce imitation sounds closely resembling engine sounds produced by full-scale automobiles as an ordinary means of transportation even when the electrically-operated model car is at a standstill. 
     2. Description of the Prior Art 
     It has generally been noted that funs of electrically-operated mobile model toys such as electrically-operated model cars, planes and ships have increasingly become inclined to prefer radio-controlled ones. Conventionally, these electrically-operated mobile model toys use in most cases a plurality of dry cells connected in series or batteries to drive motors to rotate wheels, propellers or screws. The logical consequence of such a drive mechanism is extremely low noises producible from the electrically-operated mobile model toys. For many funs of radio-controlled, electrically-operated mobile model toys, however, it is of course preferable that the operating condition of the electrically-operated mobile model toys is as close as possible to that of full-scale automobiles, planes and ships. More precisely, in case of an electrically-operated model car, for example, it is desirable that it can produce imitation sounds well matching the changing state of operation--racing the engine with a loud roar before starting or driving at varying driving speeds, and even simulate a small vibration as seen in actual cars before starting. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide an electrically-operated mobile model toy which is designed taking the above-mentioned respects into consideration to provide a sense of presence obtainable heitherto only from actual cars even when it is at a standstill before starting. 
     Accordingly, it is an object of the present invention to provide an electrically-operated mobile model toy in which an imitation sound generator and a start control device are provided so that user of electrically-operated mobile model toys embodying the present invention can feel as a sense of presence the state of stoppage of the electrically-operated mobile model toy by enjoying sounds closely imitating engine sounds, for example. 
     In accordance with the above object, it is an object of the present invention to provide an unbalance/balance unit which makes the body of an electrically-operated mobile model toy vibrate slightly when it is in the &#34;stop&#34; state so as to produce a sense of presence which has hitherto been obtainable only from an actual automobile. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a top view of the chasis with its exterior detached of a radio-controlled car which represents a typical embodiment of the present invention, 
     FIG. 2 an exploded perspective view of the drive motor section of the said embodiment, 
     FIG. 3 an illustration which explains the operating principle of the unbalance/balance unit of the said embodiment and 
     FIG. 4 an illustration which explains the operating principle of the clutch show of the said embodiment. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In FIGS. 1 to 4, numeral 1 represents a base plate of the chasis, 2-1 and 2-2 front wheels, 3-1 and 3-2 rear wheels, 4 a connecting rod to connect levers 2-3 and 2-4 which operate in association with the front wheels 2-1 and 2-2, 5 a interlocking rod, 6 a servo-motor and 7 a working shaft of the servo-motor 6 which operates the interlocking rod 5 via the lever 2-3 or operates the lever 2-4 via the connecting rod 4. 
     Numeral 8 is a DC power source consisting of batteries, etc., 9 a receiver, 10 a cylinder or a cylindrical, polyhedral hollow box, 11 a striking rod, 12 a striking face, 13 a striking rod holder, 14 a curved top end of the striking rod 11 to strike the striking face 12 and 15 a bottom end of the striking rod 11. The striking rod 11 is held in position through the striking rod holder and the curved top end 14 is in contact with the striking face 12 on the hollow box 10. The striking rod 11, striking face 12 and hollow box 10 comprise an imitation sound generator of the present invention. 
     Numeral 16 represents a speed controller, 17 a drive motor, and 18 a rotating shaft of the drive motor 17. The said power source 8 supplies electric power to the receiver 9 and the servo-motor 6 fixed on the chasis base plate 1 and to the drive motor 17 via the speed controller 16. 
     Numeral 19 is an operating disc which actuates the striking rod 11 and 20 a small operating ring. The small operating ring 20 is secured in position to the operating disc 19 by a set screw 20-1 and is disposed so as to flip the bottom end 15 of the striking rod 11 as the operating disc 19 rotates. Into a center hole 19-2 provided on a center axis 19-1 of the operating disc 19 is inserted the rotating shaft 18, and the operating disc 19 is secured in position by a screw 19-3 to the drive motor 17. Additionally, a protrusion 19-4 is provided on the other side of the operating disc 19 to receive a balance weight which will later be discussed. 
     Numeral 21 represents a clutch base in the upper half of which two openings 21-1 and and 21-1 and a center axis 21-2 are provided. Numeral 22 indicates a balance weight which has a vertical opening 22-1 in its center and is supported at its bottom on an approximately diamond-shaped, elastic supporting rod 22-2. A shaft screw 23 is inserted through the said vertical opening 22-1 and secured in position in the upper half of the clutch base 21, its bottom end 22-3 resting on the said protrusion 19-4 so that the said balance weight 22 can move freely upward and downward through the vertical opening 22-1. The supporting rod 22-2 is secured in position by a set screw 24 to the lower half of the clutch base 21 so that the balance weight 22 may be pulled centripetally by the elasticity of the supporting rod 22-2, and the unbalance/balance unit consisting of the clutch base 21 and the balance weight 22 may be balanced when the balance weight 22 moves upward centrifugally through the vertical opening 22-1 against the elasticity of the supporting rod 22-2 to reach the upper limit. 
     Numeral 25 represents clutch shoes which, together with a clutch bell later discussed, comprises a start control device. Numeral 26 refers to a clutch spring. Numeral 27 indicates a shallow cylindrical clutch ball one side of which is opened, the clutch shoes 25 and 25 being rotatably supported on the protrusions 21-3 and 21-3 provided on the clutch base 21 at one end 25-1 as shown clearly in FIG. 4. Both ends of the clutch spring 26 are inserted into insertion holes 25-2 and 25-2 provided at the other end of the clutch shoes 25 and 25 so that the elasticity of the clutch spring 26 may allow the clutch shoes 25 and 25 to be closed (as illustrated by solid lines in FIG. 4). In the clutch bell 27 housed are the clutch shoes 25 and 25 which are disposed so as to be covered with the clutch base 21. The center axis 21-2 of the clutch base 21 passes loosely through a center hole 27-1 of the clutch bell 27 and a center cavity 25-3 of the clutch shoes 25 and 25 and further passes loosely through a gear 28 on the opposite side of the clutch bell 27. The clutch bell 27 is secured in position unremovably by a nut 31 indicated in FIG. 1 via an E ring 30. In other words, the said clutch bell 27 and gear 28 are supported rotatably with respect to the said center axis 21-2, and the gear 28 transmits rotating force to the rear wheels 3-1 and 3-2 via a differential gear 29, etc. 
     The operation of the present invention which is constructed as above-stated will now be explained. 
     As illustrated in FIG. 1, when the drive motor 17 is turned on to rotate by controlling the speed controller 16 using operation signal received by the receiver 9, the operating disc 19 fixed on the rotating shaft 18 begins to rotate as the drive motor 17 rotates. Then, the small operating rings 20 and 20 mounted on the operating disc 19 move along the circumference and flip the bottom end 15 of the striking rod 11 twice for every revolution of the operating disc 19. To this end, the striking rod 11 is adapted to vibrate vertically due to the elasticity of the striking rod 11 and allow the curved top end 14 to strike the striking face 12 of the hollow box 10. As a result, the hollow box 10 produces sound of mixed tones. The basic frequency of the sound thus produced increases linearly with the number of revolutions of the drive motor 17, a secret for the close sound imitability of the present invention, e.g., a loud roar before engine-start or drumming sounds at high r.p.m. 
     As the operating disc 19 rotates and the hollow box 10 produces engine sounds, the clutch base 21 connected to the said operating disc 19 by the center axis 21-1 also begins to rotate. When the drive motor 17 rotates at low speeds, the balance weight 22 is located low as illustrated by solid lines in FIG. 3. Because of this, an imbalance will be produced in the unbalance/balance unit between the upper half and lower half as illustrated, thereby causing the body to vibrate. This vibration resembles very closely the slight vibration encounted by actual automobiles when revving up the engine in the &#34;stop&#34; state. In this state, the clutch shoes 25 and 25 secured at their ends 25-1 and 25-1 to the clutch base 21 also rotate, but they run idle in the clutch bell 27 because the centrifugal force is not strong enough to make them open against the clutch spring 26 as illustrated by dotted lines in FIG. 4 and, for the same reason, the clutch bell 27 will not rotate. Therefore, the rear wheels 3-1 and 3-2 interlocked with the gear 28, etc. will not rotate, thus making the body standstill. As the number of revolutions of the drive motor 17 rises, the sound produced from the hollow box will become louder and simultaneously the unbalance/balance unit will rotate at increasing speeds, thus causing the balance weight 22 to move upward through the vertical opening 22-1. When the r.p.m. of the drive motor 17 reaches a preset level, the clutch shoes 25 and 25 which rotate in association with the clutch base 21 will become increasingly opened as illustrated by dotted lines in FIG. 4 against the elasticity of the clutch spring 26 to come in contact with the inner wall of the clutch bell 27. As a consequence, the clutch bell 27 will be driven to rotate by the frictional linkage of the clutch shoes 25 and 25 and make the rear wheels 3-1 and 3-2 rotate via the gear 28 and the differential gear 29 as shown clearly in FIG. 1. Thus, the radio-controlled car starts with a roaring sound, reaching a driving state. In this running state, the balance weight reaches an upper limit and the unbalance/balance unit becomes balanced, thus eliminating virtually vibration of the body. 
     Turning the radio-controlled car from its course can be accomplished by driving the servo-motor 6 by the drive signal from the receiver 9 which has received the operation signal to actuate the working shaft 7 as illustrated, for example, by the black arrow in FIG. 1. By doing this, the direction of the front wheels 2-1 and 2-2 which operate in association with the levers 2-3 and 2-4 will be changed in a well known fashion. In this case, more precisely, the radio-controlled car will turn to the downward direction illustrated in the figure. 
     As explained in the above, with the present invention, operators of an electrically-operated model car with a radio control, for example, can enjoy an exciting sense of presence as if they were a real driver of a real car throughout the driving cycle from start to stop since the present invention features an imitation sound generator that can produce sounds closely resembling those from actual car engines. Further, the unbalance/balance unit incorporated in the present invention makes it possible to make, for example, the body vibrate to a relatively large extent when, for example, the motor begins to be driven, decrease the vibration as the number of motor revolutions increases and virtually eliminate the vibration at the time of starting. In other words, operators of an electrically-operated model car, for example, embodying the present invention can enjoy the changing vibration of the body an ordinary car, for example, from &#34;engine-key ON&#34; to &#34;engine Start&#34;. Thus, the present invention makes it possible for operators of electrically-operated mobile model toys to have a lifelike feeling of their standstill state, in particular.