US3713093A

US3713093A - Vehicle speed alarming device

Info

Publication number: US3713093A
Application number: US00119666A
Authority: US
Inventors: M Matsumura
Original assignee: Kawasaki Heavy Industries Ltd
Current assignee: Kawasaki Heavy Industries Ltd; Kawasaki Motors Ltd
Priority date: 1971-03-01
Filing date: 1971-03-01
Publication date: 1973-01-23
Anticipated expiration: 1990-01-23

Abstract

A rotating permanent magnet of a speedometer affords a rotational force for a non-magnetic element with a switch operating member provided thereon. A switch contact is arranged to make a reciprocal motion relative to the non-magnetic element. When the speed has reached an alarming level, the switch contact is closed by engagement with the switch operating member, whereby an alarm is issued.

Description

United States Patent Matsumura N l Jan. 23. 1973 I 1 VEHICLE SPEED ALARMING DEVICE 2992,419 7/1901 Hayes 340/203 2,154,670 4/]939 D all .340/263 UX Inventor Masakms lnmngum 2,952,0ll 9/1960 .340/263 Japan 2,992,300 7/196! Zargarpur 340/263 X [73] Assignee: Kawasaki Jukogyo Kabushiki Kaisha Kobe shi, Japan Primary ExammerAlvm H. Waring h l 197 Atlr)rney-Stevens, Davis, Miller & Mosher [22] Filed: Marc l 211 Appl. N0.: 119,666 [571 ABSTRACT A rotating permanent magnet of a speedometer af- [52] U S Cl. 340/62 340/263 fords a rotational force for a non-magnetic element [5'] 6 21/00 with a switch operating member provided thereon. A [58] Fie'ld D 62 263 switch contact is arranged to make a reciprocal m0- tion relative to the non-magnetic element. When the speed has reached an alarming level, the switch con [56] Reerences Cited tact is closed by engagement with the switch operating UNITED STATES PATENTS member, whereby an alarm is issued.

2,920,154 1/1960 Allen ..340/263 X 9 Claims, 9 Drawing Figures PATENTEDJMI 23 I975 SHEET 1 [1F 3 If. U m I 9 .5

FIG.3

FIG.|

FIG.2

VEHICLE SPEED ALARMING DEVICE BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a speed alarming device and more specifically to a speed alarming device for use with vehicles having a prime mover, which issues an alarm when the vehicle speed exceeds a predetermined level.

2. Description of the Prior Art Conventional speed alarming devices are broadly classified into an electrical type and a mechanical type. The electrical type device is so designed that the rotational position of an alarming speed setting plate mounted on the indicating pointer spindle of a speedometer is detected by electrical means, such as an electromagnetic coil, without contacting said setting plate, and has the advantage of being small in size and light in weight, but has the disadvantage that it is complicated in construction and expensive and is liable to malfunction. On the contrary, the mechanical type device is less liable to malfunction but, since the alarm contacts are directly closed and opened by the rotational force of the indicating pointer of a speedometer, an extremely large driving force is required and hence the device is not applicable to small-sized speedometers.

SUMMARY OF THE INVENTION The present invention, therefore, has for its object the provision of a speed alarming device which eliminates the disadvantages of the conventional devices set forth above, and which does not exert excessive load on the pointer spindle of a speedometer and yet is capable of detecting an alarming speed mechanically.

Another object of the invention is to provide a speed alarming device which is capable of issuing alarms at two different speeds.

Still another object of the invention is to provide a speed alarming device which is small in size and light, and which can be incorporated, for example, in smallsized speedometers for use with motor bicycles.

The speed alarming device according to the invention comprises an alarming contact operating member rotatable with the indicating pointer of a speedometer and a pair of alarming contacts so arranged as to make constantly a reciprocal motion toward and away from said operating member, said contact operating member being placed in a contact operating position when the vehicle speed has reached an alarming level and said contacts being closed by engagement with said operating member when they are moved toward said operating member.

In the device of the invention, since the switch contacts are repeatedly engaged by the operating member at the alarming speed, the switch contacts producing a continuous electric signalare preferably of the bistable type so that, once the switch contacts have been closed by the operating member, they will not be opened again even after they are disengaged from the operating member. In this case, means must be provided to open the switch contacts when the vehicle speed has dropped below the alarming speed. Further, delay means may be provided in a circuit including the switch contacts, so that the signal will not be interrupted even ifthe contacts are opened in a short period of time.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view showing an embodiment of the device according to the invention;

FIG. 2 is a cross-sectional view showing the essential portion of the embodiment of FIG. 1;

FIG. 3 is a perspective view showing another embodiment of the device according to the invention;

FIGS. 40 to 4c are illustrative views showing the operation of still another embodiment of the device according to the invention;

FIGS. 5 and 6 are wiring diagrams exemplifying the control circuit for obtaining a continuous electric signal; and

FIG. 7 is a perspective view showing still another embodiment of the device according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIGS. 1 and 2, a flexible shaft 1 ofa speedometer is rotated at a rate proportional to the vehicle speed. The shaft 1 is connected with a worm gear 2 which in turn is connected integrally with a magnetic cup3 having a permanent magnet 17 disposed therein. When the cup 3 is rotated, an eddy current is generated in a nommagnetic cup 5 coaxial with an in dicating pointer 4, whereby a pointer driving torque is created. A hair spring 6 rotates the indicating pointer 4 to a point where the force of said hair spring 6 is just balanced by the torque created in the cup 5, and thus the speed in that instance is indicated by the pointer 4. A spindle 14 of the indicating pointer 4 is separated from the permanent magnet in the cup 3 and rotatable relative thereto. The rotation of the worm gear 2 is transmitted to an odometer 7 through a transmission mechanism including a horizontal shaft 35, a vertical shaft 8 and a horizontal shaft 36. The above-described construction is common for all conventional speedometers for automobiles. According to the present invention, a switch operating member, i.e. a sectoral speed setting plate 13, is attached to the nonmagnetic cup 5 mounted on the pointer spindle 14, and switch contacts 11 are provided adjacent the speed setting plate 13. The contacts 1 1 are carried on one end of a pivot lever 10 which is pivotably mounted on a pin 37 fixed to the vehicle body. The other end of the lever 10 is in engagement with a cam 9 mounted on the vertical shaft 8 through which the odometer is driven. The lever 10 is held in pressure engagement with the cam 9 under the biasing force of a spring 12. The contacts 11 are connected in series with a buzzer 15 and a power source 16.

With the arrangement described above, when the vehicle speed is below the alarming speed, the speed setting plate 13 is not in a position engageable with the contacts 11. Therefore, the contacts 11 make a reciprocal motion toward and away from the speed setting plate 13, incident to the pivotal movement of the lever 10 and will not be brought into contact with and closed by the setting plate '13 even when they are moved toward the setting plate. Now, when the vehicle speed is accelerated and exceeds the alarming speed, the speed setting plate 13 is located in the position engageable with the contacts 11. and contacts 11 are closed by engagement with the setting plate 13 when they are moved toward setting plate incident to the pivotal movement of the lever 10 (the positions of the contacts 11 being indicated by the solid lines in FIG. 2). In this case, the circuit formed by the buzzer 15, the power source 16, the contacts 11 and a line 38 is closed and the buzzer 15 is actuated by the power source 16 to issue an alarm. This circuit preferably has a delay circuit incorporated therein as will be described later. In this embodiment, since the contacts 11 are carried on the constantly pivoting lever 10 and, therefore, con stantly reciprocate relative to the speed setting plate 13, the setting plate 13 is shiftable to the contact operating position when the contacts 11 are in positions spaced from said setting plate 13 as indicated by the broken lines in FIG. 2. Therefore, the force to close the contacts 11 provides little resistance to the rotation of the speed setting plate 13 or pointer spindle 14. This makes it possible to use a relatively small magnet for the magnet 17 and hence enables the entire mechanism to be small in size.

FIG. 3 shows another embodiment of the invention, in which parts similar to those in the preceding embodiment are indicated by the same reference numerals with character a suffixed thereto. In this embodiment, a speedometer 20 is operated in the usual manner from a flexible shaft la through a shaft having a worm gear. The worm gear 19 is meshing with a worm gear 18 provided on a horizontal shaft, and a cup 3a having a permanent magnet (not shown) mounted therein is connected at one end of the horizontal shaft. Similar to the preceding embodiment, a non-magnetic cup 5a carrying a switch contact operating member, Le. a speed setting plate 13a, is received in the cup 3a in a manner to encircle the permanent magnet, the cup 5a being rotatably supported by a shaft 14a. The rate of rotation of the cup 5a is regulated by a hair spring 6a according to the vehicle speed. The shaft having the worm gear 18 is formed with another worm gear 2a which drives a shaft 8a arranged at substantially right angles to said shaft. The shaft 8a is journaled in a bracket 22 which is connected to a supporting plate 21 by means of a slot and a screw in such a manner that the position thereof is adjustable, the supporting plate 21 being secured to the vehicle body. Further, the shaft 8a has mounted thereon a cam 9a similar to the cam 9 in the preceding embodiment. A generally L-shaped lever 10a is pivotably connected at one end to the bracket 22 and carries a pair of switch contacts 11a on the other'end thereof. A tension spring 12a is extended between the flexed portion of the L-shaped lever 10a and the bracket 22. As a result, the intermediate portion of the lever 10a is held in contact with the cam 9a under the biasing force of the spring 12a. Thus, it will be understood that the switch contacts 110 carried on the free end of the lever 10a are caused to make a reciprocal motion incident to the rotation of the shaft 8a. Similar to the preceding embodiment, the switch contacts lla are arranged adjacent the cup 5a having the speed setting plate 130 attached thereto. The arrangement is such that when the speed setting plate 13a is located in a position engageable with the switch contacts 11a upon rotation of the cup 5a, the switch contacts 11a are moved downward and closed by the speed setting plate 13a by engagement therewith. Reference numerals 15a and 16a respectively designate a buzzer and a power source electrically connected with the contacts lla as in the preceding embodiment.

According to this embodiment, the bracket 22 may conveniently be adjusted to a position corresponding to a desired alarming speed, by providing a scale 39 on the supporting plate 21 and a cooperating index point 40 on the bracket 22.

In each of the embodiments described above, the switch contacts 11 or 11a are opened and closed intermittently and therefore, the electric signal is issued also intermittently. According to the invention, means may be incorporated in the device to make the electric signal continuous.

Such means is exemplified in FIGS. 4a to 4c, in which parts similar to those in the preceding embodiments are indicated by the same reference numerals with character b suffixed thereto. In the arrangement shown, the switch contacts are constructed into a bistable type. Namely, one of the contact strips 30 of the switch contacts 11b is secured to a lever (not shown) similar to the lever 10 or 10a in the preceding embodiment, and the other contact strip 24 is pivotally connected to the lever by a pin 25. Also pivotally mounted on the pin 25 is a spring support plate 23 which is urged to move away from the contact strip 24 by a compression spring 26 extended between the upper portion of the spring support plate 23 and the contact strip 24. The pivotal movement of the support plate 23 is limited by means not shown, such that the support plate 23 is only shiftable, for example, between the position shown in FIG. 4a and the position shown in FIG. 4b. In the position of the support plate 23 shown in FIG. 4a, the spring 26 acts to hold the switch contacts 11b in an open position. Now, when the vehicle speed has reached the alarming level, the speed setting plate 13b is located in a position engageable with an engaging portion of the spring support plate 23. Therefore, an engaging portion 27 of the spring support plate 23 is engaged by the speed setting plate 131) when the switch contacts 11b are on the leftward stroke, whereby said spring support plate 23 is caused to make a pivotal movement in a clockwise direction and, as a result, the contact strip 24 is caused to make a pivotal movement in a counterclockwise direction by the snapping action of the spring 26 and thus the switch contacts 11b are closed as shown in FIG. 4b. When the vehicle speed has dropped below the alarming level, the speed setting plate 13b is released from engagement with the engaging portion 27 of the spring support plate 23. In this case, the spring support plate 23 is moved further to the left from the position indicated by the solid line in FIG. 4b, in the leftward stroke of the switch contacts 11b, so that it is engaged at its lower end by a projection 28 and caused to make a pivotal movement in a counterclockwise direction as shown in FIG. 40, whereby it is returned to the position shown in FIG. 4a and the switch contacts 11b are opened. It will, therefore, be understood that, with the arrangement described above wherein the switch contacts 11b are of a bistable type utilizing the snapping action of the spring 26, the alarming signal is rendered continuous.

FIGS. 5 and 6 respectively show electric circuits which enable a continuous output signal to be obtained electrically from the intermittently opened and closed switch. Each circuit is operative such that a capacitor C in an alarm circuit 29 is charged while a switch S is closed, and while the switch S is opened, the discharge current of the capacitor C is supplied to the base electrodc of a transistor Tr, or Tr through a resistor R, whereby the buzzer is sounded continuously. ln NUS. 5 and 6, reference character 'lr, designates a PM transistor, 'lr a NPN transistor and D a diode to protect transistors Tr, and "fr- It will be understood that according to the circuit of FlG. 6, the speed setting plate 13 can be used as the grounded electrode of the switch S and the construction of the contacts 11 can be further simplified.

According to the present invention, as described above, the force to close the switch contacts does not provide resistance to the rotation of the

non-magnetic cup

5, 5a or 517, so that the size of the

magnet

17, 17a or 17b can be reduced and the alarming device can be incorporated in small-sized speedometers, e.g. those of motor bicycles.

Although in the embodiments described and illustrated herein, the speed alarming device includes only one pair of switch contacts 11, it may be arranged such that two or more pairs of contacts provided therein are respectively closed at different speeds, so that an alarm will be sounded at two or more different speeds. Such an arrangement is exemplified in FIG. 7. According to the arrangement shown, the contacts 11c and 11d are provided at the substantially mid portion of the lever 10, and the

buzzers

15c and 15d are connected to the power source 16 through said contacts respectively. In operation, when the vehicle speed increases, the speed setting plate 13 is located in a position engageable with the contacts 110 at first, to close said contacts 110 and energize the buzzer 15c, whereby the first alarm is sounded. Then, the speed setting plate 13 is rotatably shifted further as the vehicle speed further increases, and located in a position engageable with the contacts 11d, to close contacts 11d and energize the buzzer 15b, whereby the second alarm is sounded.

In the above-described embodiment, the speed setting plate is made of a sectoral member having a wide width and the buzzer keeps sounding while the vehicle speed is higher than a predetermined level. However, it is possible to sound the buzzer only for a period when the vehicle speed is in a certain short range, for example, by forming the speed setting plate of a sectoral member having a narrow width. ln this case, it should be noted that, with the arrangement of FIG. 7, the first alarm will not continuously sound up to the second alarm.

While the invention has been described with reference to the structure disclosed herein, it is not confined to the details set forth but it is intended to cover such modifications or changes as may come within the scope of the following claims.

Iclaim:

l. A speed alarming device comprising a permanent magnet fixed to a shaft rotated at a speed proportional to the vehicle speed; a non-magnetic member rotatably arranged in opposed relation to said permanent magnet, said non-magnetic member being so constructed as to be rotated by a rotational force created by said permanent magnet during rotation of said permanent magnet; spring means provided on said non-magnetic member to impart thereto a resilient force against said rotational force; a switch contact operating member fixedly attached to said non-magnetic member; switch contacts for an alarm signal circuit; and means for constantly moving said SWl ch contacts in a reciprocal motion toward and away from said non-magnetic member, said switch contact operating member being located in a position engageable with said switch contacts when the vehicle speed has reached an alarming level and said switch contacts being closed by said switch contact operating member when they are moved toward and brought into engagement with said switch contact operating member.

2. A speed alarming device according to claim 1, wherein said switch contacts are of a bistable type utilizing the snapping action of a spring and arranged such that they are held closed while the vehicle speed is at the alarming level but opened when the vehicle speed drops below said alarming level.

3. A speed alarming device according to claim 1, wherein said alarm signal circuit includes a capacitor and a transistor, and said capacitor is charged while said switch contacts are closed and discharges the current stored therein through a resistor to the base of said transistor to maintain said transistor energized temporarily while said switch contacts are opened.

4. A speed alarming device according to claim 1, wherein said alarm signal circuit includes a plurality of switches which are respectively actuated at different vehicle speeds.

5. A speed alarming device according to claim 1, wherein means are provided to adjust the distance between said switch operating member and said switch contacts and to indicate the alarming speed.

6. A speed alarming device according to claim 1, wherein said alarm signal circuit includes an overvoltage preventing diode connected with the output electrode of a transistor.

7. A speed alarming device according to claim 1, wherein an odometer is operatively connected through a transmission mechanism to said shaft which is rotated at a speed proportional to the vehicle speed.

8. A speed alarming device according to claim 1, wherein the reciprocal motion of said switch contacts toward and away from said switch operating member is effected by a structure comprising a second shaft rotated by said first shaft, cam means mounted on said second shaft, and a lever biased into engagement with said cam means by a spring with one end thereof pivotably supported and carrying said switch contacts on the otherend.

9. A speed alarming device according to claim 1, wherein said switch operating member is made of a seetoral member having a width corresponding to the range of vehicle speeds for which an alarm is desired.

Claims

1. A speed alarming device comprising a permanent magnet fixed to a shaft rotated at a speed proportional to the vehicle speed; a non-magnetic member rotatably arranged in opposed relation to said permanent magnet, said non-magnetic member being so constructed as to be rotated by a rotational force created by said permanent magnet during rotation of said permanent magnet; spring means provided on said non-magnetic member to impart thereto a resilient force against said rotational force; a switch contact operating member fixedly attached to said non-magnetic member; switch contacts for an alarm signal circuit; and means for constantly moving said switch contacts in a reciprocal motion toward and away from said non-magnetic member, said switch contact operating member being located in a position engageable with said switch contacts when the vehicle speed has reached an alarming level and said switch contacts being closed by said switch contact operating member when they are moved toward and brought into engagement with said switch contact operating member.

8. A speed alarming device according to claim 1, wherein the reciprocal motion of said switch contacts toward and away from said switch operating member is effected by a structure comprising a second shaft rotated by said first shaft, cam means mounted on said second shaft, and a lever biased into engagement with said cam means by a spring with one end thereof pivotably supported and carrying said switch contacts on the other end.

9. A speed alarming device according to claim 1, wherein said switch operating member is made of a sectoral member having a width corresponding to the range of vehicle speeds for which an alarm is desired.