EP0849822A2 - Antenna support angle adjustment mechanism and vehicular rod antenna device - Google Patents

Antenna support angle adjustment mechanism and vehicular rod antenna device Download PDF

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Publication number
EP0849822A2
EP0849822A2 EP97310209A EP97310209A EP0849822A2 EP 0849822 A2 EP0849822 A2 EP 0849822A2 EP 97310209 A EP97310209 A EP 97310209A EP 97310209 A EP97310209 A EP 97310209A EP 0849822 A2 EP0849822 A2 EP 0849822A2
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EP
European Patent Office
Prior art keywords
antenna
support angle
rod
mounting base
angle adjustment
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP97310209A
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German (de)
French (fr)
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EP0849822A3 (en
Inventor
Junichi Kohinata
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Harada Industry Co Ltd
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Harada Industry Co Ltd
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Filing date
Publication date
Application filed by Harada Industry Co Ltd filed Critical Harada Industry Co Ltd
Publication of EP0849822A2 publication Critical patent/EP0849822A2/en
Publication of EP0849822A3 publication Critical patent/EP0849822A3/en
Withdrawn legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/08—Means for collapsing antennas or parts thereof
    • H01Q1/084—Pivotable antennas

Definitions

  • the present invention relates to a mechanism for variably adjusting the support angle of a vehicular rod antenna that is attached to the roof or like of an automobile and a vehicular rod antenna device using this mechanism.
  • a vehicular rod antenna device that is attached to the roof or the like of an automobile is designed so that an antenna mounting base (having therein a feeding section to be connected with a feeder) is mounted on the roof or some other body wall of the automobile, and the proximal end portion of a rod antenna is removably attached to the mounting base by using screw-coupling means.
  • the antenna mounting base is fixed at a specific angle to the body wall of the vehicle.
  • the proximal end portion the rod antenna which may have an element length of about 150 mm to 400 mm, for example, is also fixed at a specific angle to the mounting base. If the rod antenna is subjected to too great an external force for its elasticity as it is touched by its surroundings while the vehicle is being washed or put into a garage, therefore, it may possibly be bent or broken.
  • the element length of the rod antenna is as short as about 150 mm, there is a relatively slim chance that the antenna is touched by obstacles. Accordingly, the vehicle can be put into the garage without any substantial hindrance with the antenna outside its body wall. On account of its shortness, however, this rod antenna is relatively poor in reception characteristics.
  • a rod antenna has an element length of about 400 mm, which is long enough to maintain good reception characteristics.
  • this antenna must be removed from the vehicle body every time the vehicle is put into the garage, for example, and this operation is very troublesome.
  • the vehicular rod antenna device of the variable-angle type constructed in this manner is more expensive than a fixed-angle rod antenna device. It is not very economical, therefore, to replace an existing fixed-angle antenna device with the variable-angle vehicular rod antenna device, not to mention newly attach the antenna device of this type to the vehicle.
  • the object of the present invention is to provide an antenna support angle adjustment mechanism, whereby an existing vehicular rod antenna device of the fixed-angle type can be easily transformed into a vehicular rod antenna device of the variable-angle type, and a vehicular rod antenna device furnished with this antenna support angle adjustment mechanism.
  • an antenna support angle adjustment mechanism and a vehicular rod antenna device have the following constructions.
  • FIG. 1 is a side view showing an outline of a vehicular rod antenna device according to an embodiment of the present invention.
  • numeral 1 denote a vehicle body wall (e.g., roof of an automobile) and numeral 2 denote an antenna mounting hole in the wall 1.
  • Numeral 10 denotes an antenna body, which includes an antenna mounting base 11 and a rod antenna 12.
  • An antenna support angle adjustment mechanism 20 (mentioned later) is interposed between the mounting base 11 and the antenna 12.
  • the antenna mounting base 11 is mounted in the antenna mounting hole 2.
  • the base 11 is composed mainly of a hollow conical integral casing of, e.g., a rigid synthetic resin, having a slanting underside portion.
  • a feeding section lla is contained in the casing.
  • the grounding side of the feeding section 11a is connected to an electrically conductive cylindrical portion 11d (see FIG. 2), which protrudes outward from the slanting underside portion.
  • the cylindrical portion 11d is isolatedly guided into the vehicle body through the antenna mounting hole 2 as it is attached to the vehicle body wall 1.
  • a thread portion is formed on the outer periphery of the cylindrical portion lld in the vehicle body, and a fixing nut llb is screwed on the thread portion.
  • a plurality of serrated projections P are formed on the periphery of the nut 1lb.
  • the projections P are pressed against the back of the vehicle body wall 1 so as to bite it.
  • the antenna mounting base 11 is fixed to the body wall 1, and the grounding side of the feeding section 11a is grounded.
  • the hot side of the feeding section lla is connected to a feeder 11c, which isolatedly penetrates the hollow portion of the conductive cylindrical portion 11d.
  • the rod antenna 12 can be removably attached to the top portion of the antenna mounting base 11 by means of the antenna support angle adjustment mechanism 20 (mentioned later) or in a direct manner.
  • the proximal and distal end regions of the antenna 12 constitute a large-diameter portion 12a and a small-diameter portion 12b, respectively.
  • the large-diameter portion 12a is formed by coating an antenna element (not shown) with a relatively soft synthetic resin or the like.
  • the antenna 12 can be bent deeply around the large-diameter portion 12a, as indicated by two-dot chain lines M and N in FIG. 1.
  • the proximal end portion of the rod antenna 12 is connected directly to the top portion of the antenna mounting base 11 without the aid of the antenna support angle adjustment mechanism 20, and is supported at a tilt angle ( ⁇ ) of about 50° on a plane H that is substantially parallel to the vehicle body wall 1.
  • the antenna 12 is designed so as to be able to fulfill its necessary function.
  • the antenna support angle adjustment mechanism 20 can be detachably interposed between the top portion of the antenna mounting base 11 and the proximal end portion of the rod antenna 12.
  • the antenna 12 is first disengaged from the top portion of the mounting base 11. Then, one end of the adjustment mechanism 20 is fixedly screwed onto the top portion of the mounting base 11, while the proximal end portion of the antenna 12 is fixedly screwed onto the other end of the mechanism 20. By doing this, the antenna support angle adjustment mechanism 20 is interposed in the manner shown in FIG. 1. If necessary, the rod antenna 12 can be brought down to the level of the plane H that is substantially parallel to the vehicle body wall 1, as indicated by two-dot chain line 12', by manually bending the mechanism 20 after it is attached.
  • FIGS. 2 and 3 are views showing a specific arrangement of the antenna support angle adjustment mechanism 20.
  • the adjustment mechanism 20 is composed of an antenna support angle adjustment member 24, which includes first and second coupling elements 21 and 22 having their respective opposite end portions pivotally supported by means of a pivotal portion 23, and a protective cover 30 of an elastic material covering the outer periphery of the adjustment member 24.
  • FIG. 4 is a view more specifically showing the arrangement of the antenna support angle adjustment member 24.
  • the first coupling element 21 includes a coupling portion 21a that is composed of opposite walls X and Y, formed by bending a metallic material substantially in the shape of a U, and a connecting wall Z connecting corresponding end edges of the walls X and Y.
  • a screw rod 25 is formed integrally on the underside of the coupling portion 21a.
  • the second coupling element 22 includes a thick coupling portion 22a formed by slightly crushing one end of the metallic tube material flat.
  • a pipe portion 22b, which is continuous with the coupling portion 22a, is provided with an internal thread portion 26.
  • the coupling portion 22a is held between the opposite walls X and Y of the coupling portion 21a, and is pivotally supported in a manner such that it is tightened under a given pressure by means of a pivotal mechanism 27.
  • the mechanism 27 includes a shaft screw 27a, nut 27b, and spring washer 27c.
  • the second coupling element 22 can rock when it is subjected to a fixed external rocking force. When the rocking force is removed, the element 22 can maintain its steady angular position.
  • the range of rocking motion of the second coupling element 22 is restricted by the connecting wall Z. More specifically, the rocking motion of the element 22 is restricted within a range 0 between an angular position that is substantially coincident with an extension O of the axis of the first coupling element 21 and another angular position (corresponding to the plane H substantially parallel to the mounting surface of the vehicle body wall 1) in which a part of the second coupling element 22 (22') is in contact with the upper edge of the connecting wall Z.
  • the screw rod 25 on the other end portion of the first coupling element 21, out of the first and second coupling elements 21 and 22 that are pivotally supported by means of the pivotal portion 23, as mentioned before, can be removably screwed into an internal thread portion 16, which is embedded in the top portion of the antenna mounting base 11 and connected to the hot side of the feeding section lla.
  • a screw rod 15, which is provided on the proximal end portion of the rod antenna 12, can be removably screwed into an internal thread portion 26 in the other end portion of the second coupling element 22.
  • the screw rods 15 and 25 have quite the same size. Thus, the screw rod 15 can be also screwed into the internal thread portion 16.
  • numeral 28 denotes a fixing nut for fixing the engaged state of the screw rod 25 in the internal thread portion 16.
  • the fixing nut 28 is put on the screw rod 25 by screwing in advance.
  • One end face of the nut 28 is provided with a recess 29 having a conical surface that closely fits a conical surface of the top portion of the antenna mounting base 11.
  • the screw rod 25 When the fixing nut 28 is loosened, the screw rod 25 is allowed to be screwed into or disengaged from the internal thread portion 16 of the antenna mounting base 11. Accordingly, the antenna support angle adjustment member 24 can be freely attached to or detached from the mounting base 11. If the nut 28 is tightened when the screw rod 25 is in a specific engaged state (any of states including an initial engaged state and a final engaged state), this engaged state is fixed as it is.
  • a specific engaged state any of states including an initial engaged state and a final engaged state
  • the adjustment member 24 or the rod antenna 12 can be variably set at a given support angle in a given azimuthal direction. Normally, this azimuthal direction is in line with the longitudinal direction of the vehicle body.
  • the protective cover 30 is put on the antenna support angle adjustment member 24.
  • the cover 30 is a substantially cylindrical integral member formed of, for example, an elastic material such as rubber such that the adjustment member 24 is allowed to vary the support angle.
  • One end portion of the cover 30 is formed having a socket portion 30a to be fitted on the fixing nut 28, and the other end portion having a plug portion 30b to be fitted into a conical recess 14 in the proximal end portion of the rod antenna 12.
  • a plurality of ring-shaped ribs 30c are formed on the peripheral wall of the cover 30, whereby the cover can be easily deformed when it is bent.
  • the protective cover 30 has an index R (see FIG. 1) on its outer surface for indicating the support angle adjustment direction of the antenna support angle adjustment member 24, that is, the direction of rocking motion of the rod antenna 12 around the pivotal portion 23.
  • this index may be formed by bulging opposite side portions of the cover 30 that overspread the pivotal portion 23, and if necessary, suitably coloring those portions.
  • the antenna 12 can be rocked around these bulging portions to be raised or brought down.
  • test products V each provided with an antenna support angle adjustment mechanism 20 that had been manufactured in the same manner as the one shown in FIGS. 1 to 5, and a standard product (sample for combarison) W without the adjustment mechanism 24 were measured for S/N sensitivities for AM and FM waves, and differences between obtained values were evaluated.
  • FIG. 6 is a diagram showing "results of sensitivity measurement at the strain rate of 10% for AM,” that is, results of measurement on the frequency characteristics of SG output (sensitivity) for the AM-wave S/N ratio of about 20 dB, obtained with use of three test products V1 to V3 in different modes and the standard product W as samples.
  • FIG. 7 is a diagram showing "results of sensitivity measurement at the strain rate of 3% for FM,” that is, results of measurement on the frequency characteristics of SG output (sensitivity) for the FM-wave S/N ratio of about 30 dB, obtained with use of the three different-mode test products V1 to V3 and the standard product W as samples.
  • test products V1 to V3 in the different modes and the standard product W in FIGS. 6 and 7 were obtained in the following manner.
  • the test product V1 was prepared by stretching the antenna support angle adjustment mechanism 20 interposed between the antenna mounting base 11 and the rod antenna 12 and supporting the antenna 12 at an angle of about 50° to the vehicle body wall 1.
  • the test product V2 was prepared by bending the antenna support angle adjustment mechanism 20 interposed between the antenna mounting base 11 and the rod antenna 12 and bringing down the antenna 12 so that the antenna extends substantially parallel to the vehicle body wall 1.
  • the test product V3 was prepared in the same conditions as the test product Vl except that the antenna support angle adjustment mechanism 20 was wetted with water to simulate the conditions of rainy weather.
  • the standard product W was prepared by connecting the genuine rod antenna 12 of 400-mm rod length directly to the antenna mounting base 11.
  • test product V1 to V3 can stand comparison with the standard product W in sensitivity, and that the test product V1, having its antenna support angle adjustment mechanism 20 stretched, in particular, is even higher in sensitivity than the standard product W.
  • test product V2 having its antenna support angle adjustment mechanism 20 bent
  • the test products V1 and V3, having its adjustment mechanism 20 stretched is lower, when the measurement frequency is at a relatively high level, ranging from 84 to 90 MHz.
  • the interposition of the antenna support angle adjustment mechanism 20 causes the electrical length of the rod antenna 12 to increase and shift so as to fit the reception wavelength, thus resulting in improved sensitivity.
  • the interposition of the adjustment mechanism 20 causes the electrical length of the antenna 12 to increase and shift so as not to fit the reception wavelength, thus tending to lower the sensitivity in a high-frequency band in particular. It was experimentally confirmed that the antenna can be used without any practical hindrance if any suitable countermeasure (e.g., adjustment of effective antenna length) is worked out in consideration of these circumstances.
  • the antenna support angle adjustment mechanism and vehicular rod antenna device according to the embodiment can be modified as follows:
  • the antenna support angle adjustment mechanism and the vehicular rod antenna have structures and advantages as described below.

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Abstract

An antenna support angle adjustment mechanism (20) according to the present invention is detachably interposed between an antenna mounting base (11) attached to a vehicle body wall (1) and a rod antenna (12) having a proximal end portion fixedly screwed on the base (11), and which comprises an antenna support angle adjustment member (24) composed of first and second coupling elements (21, 22) pivotally supported so that one end portion of the first coupling element (21) and one end portion of the second coupling element (22) are rockable with respect to each other, the other end portion of the first coupling element (21) forming a screw rod (25) capable of being removably screwed into the antenna mounting base (11) or the rod antenna (12), the other end portion of the second coupling element (22) forming an internal thread portion (26) capable of being removably screwed on the rod antenna (12) or the antenna mounting base (11), and a fixing nut (28) for fixing the state of screwed engagement of the screw rod (25) with the antenna mounting base (11) or the rod antenna (12), the rod antenna (12) being variably adjusted at a given support angle () in a given azimuthal direction.
Figure 00000001

Description

The present invention relates to a mechanism for variably adjusting the support angle of a vehicular rod antenna that is attached to the roof or like of an automobile and a vehicular rod antenna device using this mechanism.
In general, a vehicular rod antenna device that is attached to the roof or the like of an automobile is designed so that an antenna mounting base (having therein a feeding section to be connected with a feeder) is mounted on the roof or some other body wall of the automobile, and the proximal end portion of a rod antenna is removably attached to the mounting base by using screw-coupling means.
In the conventional vehicular rod antenna device described above, the antenna mounting base is fixed at a specific angle to the body wall of the vehicle. The proximal end portion the rod antenna, which may have an element length of about 150 mm to 400 mm, for example, is also fixed at a specific angle to the mounting base. If the rod antenna is subjected to too great an external force for its elasticity as it is touched by its surroundings while the vehicle is being washed or put into a garage, therefore, it may possibly be bent or broken.
If the element length of the rod antenna is as short as about 150 mm, there is a relatively slim chance that the antenna is touched by obstacles. Accordingly, the vehicle can be put into the garage without any substantial hindrance with the antenna outside its body wall. On account of its shortness, however, this rod antenna is relatively poor in reception characteristics.
On the other hand, a rod antenna has an element length of about 400 mm, which is long enough to maintain good reception characteristics. However, there is a risk that it may be touched by obstacles because of its increased length. Accordingly, this antenna must be removed from the vehicle body every time the vehicle is put into the garage, for example, and this operation is very troublesome.
As is generally known, there is a conventional vehicular rod antenna device in which a rod antenna is prevented from being subjected to any substantial external force by being previously fitted with an antenna support angle adjustment member so that it can be brought down as required, in order to solve the problem described above.
In general, however, the vehicular rod antenna device of the variable-angle type constructed in this manner is more expensive than a fixed-angle rod antenna device. It is not very economical, therefore, to replace an existing fixed-angle antenna device with the variable-angle vehicular rod antenna device, not to mention newly attach the antenna device of this type to the vehicle.
The object of the present invention is to provide an antenna support angle adjustment mechanism, whereby an existing vehicular rod antenna device of the fixed-angle type can be easily transformed into a vehicular rod antenna device of the variable-angle type, and a vehicular rod antenna device furnished with this antenna support angle adjustment mechanism.
To achieve the above object, an antenna support angle adjustment mechanism and a vehicular rod antenna device according to the present invention have the following constructions.
  • (1) The antenna support angle adjustment mechanism of the invention can be detachably interposed between an antenna mounting base attached to a vehicle body wall and a rod antenna having a proximal end portion fixedly screwed on the antenna mounting base, and comprises:
  • an antenna support angle adjustment member composed of first and second coupling elements pivotally supported so that one end portion of the first coupling element and one end portion of the second coupling element are rockable with respect to each other, the other end portion of the first coupling element forming a screw rod capable of being removably screwed into the antenna mounting base or the rod antenna, the other end portion of the second coupling element forming an internal thread portion capable of being removably screwed on the rod antenna or the antenna mounting base;
  • and a fixing nut for fixing the state of screwed engagement of the screw rod with the antenna mounting base or the rod antenna,
  • the rod antenna being variably adjusted at a given support angle in a given azimuthal direction.
  • (2) The vehicular rod antenna device according to the invention comprises an antenna mounting base attached to a vehicle body wall, a rod antenna having a proximal end portion removably screwed on the antenna mounting base, and an antenna support angle adjustment mechanism detachably interposed between the rod antenna and the antenna mounting base,
  • the antenna support angle adjustment mechanism including an antenna support angle adjustment member composed of first and second coupling elements pivotally supported so that one end portion of the first coupling element and one end portion of the second coupling element are rockable with respect to each other, the other end portion of the first coupling element forming a screw rod capable of being removably screwed into the antenna mounting base or the rod antenna, the other end portion of the second coupling element forming an internal thread portion capable of being removably screwed on the rod antenna or the antenna mounting base,
  • and a fixing nut for fixing the state of screwed engagement of the screw rod with the antenna mounting base or the rod antenna.
    • This invention can be more fully understood from the following detailed description when taken in conjunction with the accompanying drawings, in which:
  • FIG. 1 is a side view showing an outline of a vehicular rod antenna device according to an embodiment of the present invention;
  • FIG. 2 is a partly sectional side view of an antenna support angle adjustment mechanism according to the embodiment of the invention;
  • FIG. 3 is an exploded, partly sectional side view of the adjustment mechanism of FIG. 2;
  • FIG. 4 is a partly sectional front view of the adjustment member according to the embodiment of the invention;
  • FIG. 5 is a partly sectional side view of the adjustment member according to the embodiment of the invention;
  • FIG. 6 is a diagram showing the results of measurement (measurement of S/N sensitivity for AM-waves) on test products of the vehicular rod antenna device according to the embodiment of the invention; and
  • FIG. 7 is a diagram showing the results of measurement (measurement of S/N sensitivity for FM-waves) on a test products of the vehicular rod antenna device according to the embodiment of the invention;
    • (Embodiment)
    FIG. 1 is a side view showing an outline of a vehicular rod antenna device according to an embodiment of the present invention. In FIG. 1, numeral 1 denote a vehicle body wall (e.g., roof of an automobile) and numeral 2 denote an antenna mounting hole in the wall 1. Numeral 10 denotes an antenna body, which includes an antenna mounting base 11 and a rod antenna 12. An antenna support angle adjustment mechanism 20 (mentioned later) is interposed between the mounting base 11 and the antenna 12.
    The antenna mounting base 11 is mounted in the antenna mounting hole 2. The base 11 is composed mainly of a hollow conical integral casing of, e.g., a rigid synthetic resin, having a slanting underside portion. A feeding section lla is contained in the casing. The grounding side of the feeding section 11a is connected to an electrically conductive cylindrical portion 11d (see FIG. 2), which protrudes outward from the slanting underside portion. The cylindrical portion 11d is isolatedly guided into the vehicle body through the antenna mounting hole 2 as it is attached to the vehicle body wall 1. A thread portion is formed on the outer periphery of the cylindrical portion lld in the vehicle body, and a fixing nut llb is screwed on the thread portion. A plurality of serrated projections P are formed on the periphery of the nut 1lb. When the nut 11b is tightened, the projections P are pressed against the back of the vehicle body wall 1 so as to bite it. Thus, as the fixing nut llb is tightened, the antenna mounting base 11 is fixed to the body wall 1, and the grounding side of the feeding section 11a is grounded.
    The hot side of the feeding section lla is connected to a feeder 11c, which isolatedly penetrates the hollow portion of the conductive cylindrical portion 11d.
    The rod antenna 12 can be removably attached to the top portion of the antenna mounting base 11 by means of the antenna support angle adjustment mechanism 20 (mentioned later) or in a direct manner. The proximal and distal end regions of the antenna 12 constitute a large-diameter portion 12a and a small-diameter portion 12b, respectively. The large-diameter portion 12a is formed by coating an antenna element (not shown) with a relatively soft synthetic resin or the like. Thus, the antenna 12 can be bent deeply around the large-diameter portion 12a, as indicated by two-dot chain lines M and N in FIG. 1.
    Originally, the proximal end portion of the rod antenna 12 is connected directly to the top portion of the antenna mounting base 11 without the aid of the antenna support angle adjustment mechanism 20, and is supported at a tilt angle ( ) of about 50° on a plane H that is substantially parallel to the vehicle body wall 1. Thus, the antenna 12 is designed so as to be able to fulfill its necessary function.
    If necessary, the antenna support angle adjustment mechanism 20 can be detachably interposed between the top portion of the antenna mounting base 11 and the proximal end portion of the rod antenna 12.
    In interposing the adjustment mechanism 20 between the antenna mounting base 11 and the rod antenna 12, for example, the antenna 12 is first disengaged from the top portion of the mounting base 11. Then, one end of the adjustment mechanism 20 is fixedly screwed onto the top portion of the mounting base 11, while the proximal end portion of the antenna 12 is fixedly screwed onto the other end of the mechanism 20. By doing this, the antenna support angle adjustment mechanism 20 is interposed in the manner shown in FIG. 1. If necessary, the rod antenna 12 can be brought down to the level of the plane H that is substantially parallel to the vehicle body wall 1, as indicated by two-dot chain line 12', by manually bending the mechanism 20 after it is attached.
    FIGS. 2 and 3 are views showing a specific arrangement of the antenna support angle adjustment mechanism 20. As shown in FIGS. 2 and 3, the adjustment mechanism 20 is composed of an antenna support angle adjustment member 24, which includes first and second coupling elements 21 and 22 having their respective opposite end portions pivotally supported by means of a pivotal portion 23, and a protective cover 30 of an elastic material covering the outer periphery of the adjustment member 24.
    FIG. 4 is a view more specifically showing the arrangement of the antenna support angle adjustment member 24. As shown in FIG. 4, the first coupling element 21 includes a coupling portion 21a that is composed of opposite walls X and Y, formed by bending a metallic material substantially in the shape of a U, and a connecting wall Z connecting corresponding end edges of the walls X and Y. A screw rod 25 is formed integrally on the underside of the coupling portion 21a.
    The second coupling element 22 includes a thick coupling portion 22a formed by slightly crushing one end of the metallic tube material flat. A pipe portion 22b, which is continuous with the coupling portion 22a, is provided with an internal thread portion 26. The coupling portion 22a is held between the opposite walls X and Y of the coupling portion 21a, and is pivotally supported in a manner such that it is tightened under a given pressure by means of a pivotal mechanism 27. The mechanism 27 includes a shaft screw 27a, nut 27b, and spring washer 27c.
    Thus, the second coupling element 22 can rock when it is subjected to a fixed external rocking force. When the rocking force is removed, the element 22 can maintain its steady angular position.
    As shown in FIG. 5, the range of rocking motion of the second coupling element 22 is restricted by the connecting wall Z. More specifically, the rocking motion of the element 22 is restricted within a range 0 between an angular position that is substantially coincident with an extension O of the axis of the first coupling element 21 and another angular position (corresponding to the plane H substantially parallel to the mounting surface of the vehicle body wall 1) in which a part of the second coupling element 22 (22') is in contact with the upper edge of the connecting wall Z.
    Referring again to FIGS. 2 and 3, the screw rod 25 on the other end portion of the first coupling element 21, out of the first and second coupling elements 21 and 22 that are pivotally supported by means of the pivotal portion 23, as mentioned before, can be removably screwed into an internal thread portion 16, which is embedded in the top portion of the antenna mounting base 11 and connected to the hot side of the feeding section lla. A screw rod 15, which is provided on the proximal end portion of the rod antenna 12, can be removably screwed into an internal thread portion 26 in the other end portion of the second coupling element 22. The screw rods 15 and 25 have quite the same size. Thus, the screw rod 15 can be also screwed into the internal thread portion 16.
    In FIG. 3, numeral 28 denotes a fixing nut for fixing the engaged state of the screw rod 25 in the internal thread portion 16. In assembling the antenna, the fixing nut 28 is put on the screw rod 25 by screwing in advance. One end face of the nut 28 is provided with a recess 29 having a conical surface that closely fits a conical surface of the top portion of the antenna mounting base 11.
    When the fixing nut 28 is loosened, the screw rod 25 is allowed to be screwed into or disengaged from the internal thread portion 16 of the antenna mounting base 11. Accordingly, the antenna support angle adjustment member 24 can be freely attached to or detached from the mounting base 11. If the nut 28 is tightened when the screw rod 25 is in a specific engaged state (any of states including an initial engaged state and a final engaged state), this engaged state is fixed as it is.
    If the fixing nut 28 is tightened when the first coupling element 21 is rocked at a given angle around its axis such that the antenna support angle adjustment member 24 faces in a certain direction (azimuthal direction), the adjustment member 24 or the rod antenna 12 can be variably set at a given support angle in a given azimuthal direction. Normally, this azimuthal direction is in line with the longitudinal direction of the vehicle body.
    The protective cover 30 is put on the antenna support angle adjustment member 24. The cover 30 is a substantially cylindrical integral member formed of, for example, an elastic material such as rubber such that the adjustment member 24 is allowed to vary the support angle. One end portion of the cover 30 is formed having a socket portion 30a to be fitted on the fixing nut 28, and the other end portion having a plug portion 30b to be fitted into a conical recess 14 in the proximal end portion of the rod antenna 12. Further, a plurality of ring-shaped ribs 30c are formed on the peripheral wall of the cover 30, whereby the cover can be easily deformed when it is bent.
    Preferably, the protective cover 30 has an index R (see FIG. 1) on its outer surface for indicating the support angle adjustment direction of the antenna support angle adjustment member 24, that is, the direction of rocking motion of the rod antenna 12 around the pivotal portion 23. For example, this index may be formed by bulging opposite side portions of the cover 30 that overspread the pivotal portion 23, and if necessary, suitably coloring those portions. In this case, the antenna 12 can be rocked around these bulging portions to be raised or brought down.
    (Experimental Results)
    In this experiment, test products V, each provided with an antenna support angle adjustment mechanism 20 that had been manufactured in the same manner as the one shown in FIGS. 1 to 5, and a standard product (sample for combarison) W without the adjustment mechanism 24 were measured for S/N sensitivities for AM and FM waves, and differences between obtained values were evaluated.
    FIG. 6 is a diagram showing "results of sensitivity measurement at the strain rate of 10% for AM," that is, results of measurement on the frequency characteristics of SG output (sensitivity) for the AM-wave S/N ratio of about 20 dB, obtained with use of three test products V1 to V3 in different modes and the standard product W as samples.
    FIG. 7 is a diagram showing "results of sensitivity measurement at the strain rate of 3% for FM," that is, results of measurement on the frequency characteristics of SG output (sensitivity) for the FM-wave S/N ratio of about 30 dB, obtained with use of the three different-mode test products V1 to V3 and the standard product W as samples.
    The three test products V1 to V3 in the different modes and the standard product W in FIGS. 6 and 7 were obtained in the following manner.
    The test product V1 was prepared by stretching the antenna support angle adjustment mechanism 20 interposed between the antenna mounting base 11 and the rod antenna 12 and supporting the antenna 12 at an angle of about 50° to the vehicle body wall 1.
    The test product V2 was prepared by bending the antenna support angle adjustment mechanism 20 interposed between the antenna mounting base 11 and the rod antenna 12 and bringing down the antenna 12 so that the antenna extends substantially parallel to the vehicle body wall 1.
    The test product V3 was prepared in the same conditions as the test product Vl except that the antenna support angle adjustment mechanism 20 was wetted with water to simulate the conditions of rainy weather.
    The standard product W was prepared by connecting the genuine rod antenna 12 of 400-mm rod length directly to the antenna mounting base 11.
    As seen from the measurement results of FIG. 6, it was confirmed that any of the test products V1 to V3 can stand comparison with the standard product W in sensitivity, and that the test product V1, having its antenna support angle adjustment mechanism 20 stretched, in particular, is even higher in sensitivity than the standard product W.
    As seen from the measurement results of FIG. 7, it was found that the test product V2, having its antenna support angle adjustment mechanism 20 bent, is higher in sensitivity than the standard product W, and the test products V1 and V3, having its adjustment mechanism 20 stretched, is lower, when the measurement frequency is at a relatively high level, ranging from 84 to 90 MHz.
    This phenomenon is supposed to be attributable to the following effects. In the case of AM-wave reception, the interposition of the antenna support angle adjustment mechanism 20 causes the electrical length of the rod antenna 12 to increase and shift so as to fit the reception wavelength, thus resulting in improved sensitivity. In the case of FM-wave reception, in contrast with this, the interposition of the adjustment mechanism 20 causes the electrical length of the antenna 12 to increase and shift so as not to fit the reception wavelength, thus tending to lower the sensitivity in a high-frequency band in particular. It was experimentally confirmed that the antenna can be used without any practical hindrance if any suitable countermeasure (e.g., adjustment of effective antenna length) is worked out in consideration of these circumstances.
    (Modifications)
    The antenna support angle adjustment mechanism and vehicular rod antenna device according to the embodiment can be modified as follows:
  • (i) A plurality of antenna support angle adjustment mechanisms 20 (e.g., two in number) are connected together so that the rod antenna 12 can be bent in the horizontal direction as well as in the vertical direction.
  • (ii) The screw rod 25 of the first coupling element 21 of the antenna support angle adjustment member 24 is screwed into an internal thread portion (not shown) in the proximal end portion of the rod antenna 12, and a screw rod (not shown) formed on the top portion of the antenna mounting base 11 is screwed into the internal thread portion 26 of the second coupling element 22 of the adjustment member 24.
    • (Merits of the Embodiment and Modifications)
    The antenna support angle adjustment mechanism and the vehicular rod antenna according to the embodiment and modifications have structures and advantages as described below.
  • [1] The antenna support angle adjustment mechanism according to the embodiment can be detachably interposed between an antenna mounting base (11) attached to a vehicle body wall (1) and a rod antenna (12) having a proximal end portion fixedly screwed on the antenna mounting base (11), and which comprises an antenna support angle adjustment member (24) composed of first and second coupling elements (21, 22) pivotally supported so that one end portion of the first coupling element (21) and one end portion of the second coupling element (22) are rockable with respect to each other, the other end portion of the first coupling element (21) forming a screw rod (25) capable of being removably screwed into the antenna mounting base (11) or the rod antenna (12), the other end portion of the second coupling element (22) forming an internal thread portion (26) capable of being removably screwed on the rod antenna (12) or the antenna mounting base (11), and a fixing nut (28) for fixing the state of screwed engagement of the screw rod (25) with the antenna mounting base (11) or the rod antenna (12), the rod antenna (12) being variably adjusted at a given support angle in a given azimuthal direction. According to the antenna support angle adjustment mechanism (20) constructed in this manner, an existing vehicular rod antenna device of the fixed-angle type can be replaced with, for example, a collapsible vehicular rod antenna device of the variable-angle type by only removing the antenna (12) from the mounting base (11) and interposing the adjustment mechanism (20) between them. By doing this, the vehicular rod antenna device of this type can be transformed into a variable-angle rod antenna device in which the support angle of the rod antenna (12) can be changed with respect to the mounting base (11). If there is a possibility of the rod antenna (12) being touched by its surroundings while the vehicle is being washed or put into a garage, therefore, the antenna (12) can be prevented from being broken or damaged by being brought down with the adjustment mechanism (20) bent. Thus, an existing vehicular rod antenna device of the fixed-angle type can be easily transformed into a variable-angle rod antenna device by only being fitted with the inexpensive antenna support angle adjustment mechanism (20). It was experimentally confirmed that the antenna can be used without any substantial hindrance or change in performance if the antenna support angle adjustment mechanism (20) is interposed between the antenna mounting base (11) and the rod antenna (12).
  • [2] The above antenna support angle adjustment mechanism (20) further comprises a protective cover (30) of an elastic material put on the outer periphery of the antenna support angle adjustment member (24) so as to allow support angle adjustment operation of the adjustment member (24). In this antenna support angle adjustment mechanism (20), the adjustment member (24) is externally covered by the protective cover (30), so that it can be protected against direct exposure to the weather, and enjoy fine appearance. Since its interior cannot be seen from the outside, moreover, the adjustment member (24) is theftproof.
  • [3] In the above antenna support angle adjustment mechanism (20), the protective cover (30) has an index (R) for indicating the direction of the support angle adjustment by the antenna support angle adjustment member (24). In this antenna support angle adjustment mechanism (20), the azimuthal direction in which the rod antenna (12) is raised or brought down can be definitely identified from the outside. Accordingly, there is no possibility of the antenna (12) being raised or brought down in a wrong direction or broken with an excessive force.
  • [4] The vehicular rod antenna device according to the embodiment comprises an antenna mounting base (11) attached to a vehicle body wall (1), a rod antenna (12) having a proximal end portion removably screwed on the antenna mounting base (11), and an antenna support angle adjustment mechanism (20) detachably interposed between the rod antenna (12) and the antenna mounting base (11), the antenna support angle adjustment mechanism (20) including an antenna support angle adjustment member (24) composed of first and second coupling elements (21, 22) pivotally supported so that one end portion of the first coupling element (21) and one end portion of the second coupling element (22) are rockable with respect to each other, the other end portion of the first coupling element (21) forming a screw rod (25) capable of being removably screwed into the antenna mounting base (11) or the rod antenna (12), the other end portion of the second coupling element (22) forming an internal thread portion (26) capable of being removably screwed on the rod antenna (12) or the antenna mounting base (11), and a fixing nut (28) for fixing the state of screwed engagement of the screw rod (25) with the antenna mounting base (11) or the rod antenna (12). The vehicular rod antenna device described above can fulfill quite the same function as one that is originally designed as a collapsible vehicular rod antenna device of the variable-angle type. Thus, if there is a possibility of the rod antenna (12) being touched by its surroundings while the vehicle is being washed or put into a garage, the antenna (12) can be prevented from being broken or damaged by being brought down with the antenna support angle adjustment mechanism (20) bent. Since the adjustment mechanism (20) is detachable, moreover, it can be easily replaced with a new one if it is damaged itself. In the case where the FM-wave reception sensitivity is a very important factor, furthermore, the antenna device can be readily used without the adjustment mechanism (20) thereon.

    • Claims (4)

    1. An antenna support angle adjustment mechanism (20), which can be detachably interposed between an antenna mounting base (11) attached to a vehicle body wall (1) and a rod antenna (12) having a proximal end portion fixedly screwed on the antenna mounting base (11), characterized by comprising:
      an antenna support angle adjustment member (24) composed of first and second coupling elements (21, 22) pivotally supported so that one end portion of the first coupling element (21) and one end portion of the second coupling element (22) are rockable with respect to each other, the other end portion of the first coupling element (21) forming a screw rod (25) capable of being removably screwed into the antenna mounting base (11) or the rod antenna (12), the other end portion of the second coupling element (22) forming an internal thread portion (26) capable of being removably screwed on the rod antenna (11) or the antenna mounting base (11); and
      a fixing nut (28) for fixing the state of screwed engagement of the screw rod (25) with the antenna mounting base (11) or the rod antenna (12),
      the rod antenna (12) being variably adjusted at a given support angle (  ) in a given azimuthal direction.
    2. An antenna support angle adjustment mechanism (20) according to claim 1, characterized by further comprising a protective cover (30) of an elastic material put on the outer periphery of the antenna support angle adjustment member (24) so as to allow support angle adjustment operation of the adjustment member (24).
    3. An antenna support angle adjustment mechanism (20) according to claim 2, characterized in that said protective cover (30) has an index (R) for indicating the direction of the support angle adjustment by the antenna support angle adjustment member (24).
    4. A vehicular rod antenna device comprising an antenna mounting base (11) attached to a vehicle body wall (1), a rod antenna (12) having a proximal end portion removably screwed on the antenna mounting base (11), and an antenna support angle adjustment mechanism (20) detachably interposed between the rod antenna (12) and the antenna mounting base (11),
      characterized in that
      said antenna support angle adjustment mechanism (20) including an antenna support angle adjustment member (24) composed of first and second coupling elements (21, 22) pivotally supported so that one end portion of the first coupling element (21) and one end portion of the second coupling element (22) are rockable with respect to each other, the other end portion of the first coupling element (21) forming a screw rod (25) capable of being removably screwed into the antenna mounting base (11) or the rod antenna (12), the other end portion of the second coupling element (22) forming an internal thread portion (26) capable of being removably screwed on the rod antenna (12) or the antenna mounting base (11), and
      a fixing nut (28) for fixing the state of screwed engagement of the screw rod (25) with the antenna mounting base (11) or the rod antenna (12).
    EP97310209A 1996-12-18 1997-12-17 Antenna support angle adjustment mechanism and vehicular rod antenna device Withdrawn EP0849822A3 (en)

    Applications Claiming Priority (2)

    Application Number Priority Date Filing Date Title
    JP33823796A JP3668346B2 (en) 1996-12-18 1996-12-18 Antenna support angle variable mechanism and vehicle rod antenna device
    JP338237/96 1996-12-18

    Publications (2)

    Publication Number Publication Date
    EP0849822A2 true EP0849822A2 (en) 1998-06-24
    EP0849822A3 EP0849822A3 (en) 1998-09-30

    Family

    ID=18316223

    Family Applications (1)

    Application Number Title Priority Date Filing Date
    EP97310209A Withdrawn EP0849822A3 (en) 1996-12-18 1997-12-17 Antenna support angle adjustment mechanism and vehicular rod antenna device

    Country Status (2)

    Country Link
    EP (1) EP0849822A3 (en)
    JP (1) JP3668346B2 (en)

    Families Citing this family (1)

    * Cited by examiner, † Cited by third party
    Publication number Priority date Publication date Assignee Title
    CN104201455B (en) * 2014-08-26 2017-01-11 中国科学院电子学研究所 unfolding release device of rod antenna

    Citations (6)

    * Cited by examiner, † Cited by third party
    Publication number Priority date Publication date Assignee Title
    US4074271A (en) * 1976-01-31 1978-02-14 American Electronics, Inc. Adjustable antenna holding device
    AU518846B2 (en) * 1978-02-06 1981-10-22 Gregory Owen Ackman cop
    FR2514571A3 (en) * 1981-10-12 1983-04-15 Hmp Antennefabrik Aps Rotatable support for car whip aerial - includes projecting articulation with serrated surfaces preventing rotation once locking peg is inserted
    FR2589010A3 (en) * 1985-10-21 1987-04-24 Erdi Sa Whip antenna base for vehicles
    US5252985A (en) * 1990-11-14 1993-10-12 Christinsin Alan S Whip tilt adapter
    EP0589450A1 (en) * 1992-09-24 1994-03-30 SIGMA ANTENNE S.r.l. Base for a two-way antenna

    Patent Citations (6)

    * Cited by examiner, † Cited by third party
    Publication number Priority date Publication date Assignee Title
    US4074271A (en) * 1976-01-31 1978-02-14 American Electronics, Inc. Adjustable antenna holding device
    AU518846B2 (en) * 1978-02-06 1981-10-22 Gregory Owen Ackman cop
    FR2514571A3 (en) * 1981-10-12 1983-04-15 Hmp Antennefabrik Aps Rotatable support for car whip aerial - includes projecting articulation with serrated surfaces preventing rotation once locking peg is inserted
    FR2589010A3 (en) * 1985-10-21 1987-04-24 Erdi Sa Whip antenna base for vehicles
    US5252985A (en) * 1990-11-14 1993-10-12 Christinsin Alan S Whip tilt adapter
    EP0589450A1 (en) * 1992-09-24 1994-03-30 SIGMA ANTENNE S.r.l. Base for a two-way antenna

    Also Published As

    Publication number Publication date
    JP3668346B2 (en) 2005-07-06
    EP0849822A3 (en) 1998-09-30
    JPH10178310A (en) 1998-06-30

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