US 3728906 A
An electrically-operated extending and contracting antenna which employs, instead of a reduction worm gear, a plurality of stages of reduction spur gears superior in gear engagement efficiency for transmitting power from a motor to a rotary drum, so that the loss of driving power in the reduction gear is remarkably reduced, thereby making it possible to employ an electric motor which is small in both power and size.
Description (OCR text may contain errors)
United States Patent 1191 1111 3,728,906 1451 Apr. 24, 1973 Takaki et a1.
15 1 ELECTRiCALLY-OPERATED 3.195323 7/1965 EXTENDING AND CONTRACTING ANTENNA FOR RUNNING 219491608 3/1960 AUTOMOBILES 3,016,206 1 1962 3,577,148 51971 H l h h..'.  Inventors: Nobuyoshi Takaki, A1ch1-ken; 0 u 242/54 A Tadashi Hattori Karlya both of Primary ExaminerLeonard H. Gerin Japan Attorney-Cushman, Darby & Cushman  Assignee: Nippondenso Kabushiki Kaisha,
' Kariya-shi, Aichi-ken, Japan  ABSTRACT  F11ed: Dec. 7, 1970 I An electrically-operated extending and contracting l 1 pp N03 95,703 antenna which employs, instead of a reduction worm gear, a plurality of stages of reduction spur gears su- 521 US. (:1. ..74/421 R, 242/54 A, 343/715, cngagemem cfficency 343 877 power from a motor to a rotary drum, so that the loss of driving power in the reduction gear is remarkably [51 '3 Cl "Fl6h 1/20 Holq 1/12 Holq 1/32 reduced, thereby making it possible to employ an elec-  Field of Search ..242/54 A; 343/715, m motor which is small in both power and size  References Cited 1 Claim, 3 Drawing Figures UNITED STATES PATENTS 2,709,220 5/1955 Spector ..3 43/714 X g /2 /7 l l 20 s-\ /5 //a o /3a l 4,3 60 J I 7 E ELECTRICALLY-OPERATED EXTENDING AND CONTRACTING ANTENNA FOR RUNNING AUTOMOBILES The present invention relates to improvements in or relating to the construction of an electrically-operated extending and contracting antenna for running vehicles, primarily, automobiles.
in the conventional electrically-operated antenna of this type, a worm is cut on the end of the armature shaft of a motor to rotate a worm gear engaged with it, whereby a rotary drum with an inclined peripheral surface is rotated in either of the forward and backward directions through a shock-absorbing clutch mechanism, so that a flexible wire for extending or contracting an antenna element is wound out or into a container formed around the peripheral surface of the drum, thereby to raise or lower the antenna element. The useof a worm gear as a means of power transmission as mentioned above, however, requires a highpower motor relatively large in size because of its low gear engagement efficiency, in spite of the fact that such a device provides a large gear reduction ratio, resulting in the disadvantage of a large-sized extending and contracting electrically-operated antenna. This offers a very great inconvenience when installing it on a vehicle including an automobile which cannot afford much space for such installation.
Accordingly, it is an object of the present invention to provide an electrically-operated extending and contracting antenna for a running vehicle with multi-stage reduction spur gears inserted between a motor and a rotary drum which is rotated by the motor for raising and lowering an antenna element.
According to the present invention, since a plurality of stages of reduction spur gears, instead of a reduction worm gear, are inserted in a power transmission system from a motor to the rotary drum, the gear engagement efficiency in the reduction gear is improved to such a degree as to remarkably reduce the loss of driving power. As aconsequence, not only can a small-sized low-power motor be 'used, but such a motor can be contained place into the space of the rotary drum, making it possible to produce an electrically-operated extending and contracting antenna very small in size and low in cost. In addition, the present invention very much facilitates the installation of an antenna onan automobile whichcannot afford much space for installation.
The above and other objects, features and advantages will be made apparent by the detailed description taken in conjunction with the accompanying drawings, in which:
FIG. 1 shows a front view ofthe electrically-operated extending and contracting antenna in a contracted state according to the present invention;
FIG. 2 is an enlarged view of the section cut in the plane Illl as shown in FIG. 1;
HO. 3 is a diagram showing the power transmission system as it is enlarged from the sectional plane llllll as shown in FlG. 2.
in FIGS. 1, 2 and 3, numeral 1 shows a support member for supporting a cylindrical toothed wheel 11 which will be described later, and for containing and holding a reversible motor 2 within it. Numeral 3 shows an armature shaft of the motor 2, on the end of which is fixed a spur gear 4 which in turn meshes with a largediameter toothed wheel 60 of the spur gear 6 which is rotatably fitted on the shaft 5 provided on the support member 1; The small-diameter toothed wheel 6b formed integrally with the wheel 6a is engaged with the large-diameter toothed wheel 8a of the spur gear 8 which is rotatably fitted on the shaft 7 provided on the support member 1. Further, the small-diameter toothed wheel 8b integrally formed with the wheel meshes with the large-diameter toothed wheel 10a of the spur gear 10 which is rotatably fitted on the shaft 9 provided on the support member 1, while the small-diameter toothed wheel 10b integrally formed with the toothed wheel 10a meshes with the cylindrical wheel 11. This cylindrical toothed wheel 11 is rotatably fitted on the periphery of the cylinder portion 1a of the support member 1, and a ring 12 is provided to prevent the cylindrical toothed wheel 11 from being slipped off in the axial direction. Numeral 13 shows a rotary drum for winding in and out the flexible wire 15 for lowering and raising the antenna element 14. The rotary drum 13 is provided with a plurality of hooks 13a which are fitted into a plurality of grooves 11a on the periphery ofthe cylindrical toothed wheel 11 so that the rotary drum 13 rotates integrally with the toothed wheel 11. One end of the flexible wire 15 is connected with the antenna element 14, the other end thereof being calked fixedly at the cut-up portion 16 of the bottom of the rotary drum l3. Numeral 17 shows a drum cover which is fixed on the support member 1 by means of a screw 18 and which also prevents the motor 2'from slipping off in the axial direction. Numeral 19 shows a gear cover and 20 a ring for preventing the rotary drum 13 from slipping offin the axial direction.
The operation of the present invention of the above construction will now be explained. When the motor 2 is started by closing a power switch (not shown in the drawings), the rotary drum 13 is rotated through a reduction spur gear consisting of the wheels 4, 6, 8 and 10 and the cylindrical gear 11, whereby the flexible wire is wound off to raise the antenna element 14, or it is wound in the lower the antenna element 14. Since a reduction spur gear, in place of a reduction worm gear, is employed for power transmission from the motor 2 to the rotary drum 13, a very high gear engagement efficiency is obtained, resulting in a very small loss of the power for driving the rotary drum, so that a small-sized low-power motor can be used for the motor 2 with the result that the motor 2, as shown in the embodiment, can be contained in the cylindrical portion 1a of the support member 1 which rotatably supports the rotary drum through the cylindrical gear 11. Thus, the driving mechanism for an electrically-operated antenna can be made much smaller than that of the conventional antenna, thereby to provide a great advantage in the installation of such an antenna on an automobile or other vehicles in which there is not much space for such installation. Also, since a low-power motor can be used for the motor 2, the manufacturing cost is low.
The above-mentioned embodiment is not equipped with a clutch mechanism, and therefore the motor 2 is restrained from rotating when the antenna element 14 reaches the upper or lower limit, but because of the small power of the motor 2, no large current flows in the motor 2 so that it is rarely damaged if the duration of such restraint is short. Needless to say, a shock-absorbing'clutch mechanism may be provided between the cylindrical wheel 11 and the rotary drum 13 for complete protection of the antenna from damage by heat.
In the next place, in assembling the above-mentioned embodiment of the present invention, the reduction spur gear and the rotary drum 13 installed on the support member 1 are produced separately from the motor 2, and then the motor 2 is inserted into the cylindrical portion 1a of the support member 1. For this reason, the workability of the invention is greatly improved compared with the conventional method in which the motor, reduction gear and other components are fitted one by one.
What is claimed is:
1. An electrically-operated extending and contracting antenna for running vehicles comprising:
a motor having a driving shaft, a supporting means having a cylindrical portion whose inner surface extends in face-to-face relationship with the outer periphery of said motor for fixedly supporting said motor therein,
a cylindrical toothed wheel having a cylindrical portion extending around and rotatably supported on the outer periphery of said cylindrical portion of said supporting means and a toothed portion provided at one end of said cylindrical portion of said wheel,
a first spur gear mounted on the end of said driving shaft,
a train of spur gears rotatably supported on said supporting member and engaged in power-transmittable relationship between said first spur gear and said toothed portion of said cylindrical toothed wheel,
a flexible wire having one end connected to an antenna element and another end fixed to a drum,
drum means disposed around and fixed to said cylindrical portion of said cylindrical toothed wheel for rotation together with the same, and providing a surface upon which said flexible wire may be wound, said surface extending adjacent 'to said cylindrical portion of said cylindrical toothed wheel, and
-a drum cover fixed on said support means and adapted to enclose said motor and said drum means therein.