Warning system for indicating absence of emergency spare tire from a spare tire container

An ON-OFF switch device is mounted in an emergency spare tire container and assumes its ON-condition when the tire is absent from the container. A warning device is electrically actuated by the switch in such a mannner that when the switch assumes the ON-condition due to absence of the tire from the container, the warning device gives a warning.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates in general to a safety system of a motor 
vehicle, and more particularly to a warning system which indicates whether 
an emergency spare tire is in the spare tire container or not, that is to 
say whether the emergency spare tire is being practically used or not. 
2. Description of the Prior Art 
For obtaining a larger space in a baggage room and/or reducing the weight 
of the vehicle, some motor vehicles are equipped with an "emergency spare 
tire" which is designed to be used only in case of an emergency. The 
emergency spare tire, sometimes called a space saver tire or temporary 
tire, is one which is reduced in weight and size as compared with a usual 
tire and is expanded to the size of the usual tire, upon its practical 
use, by feeding a pressurized air thereinto. 
As is understood from the above, the essential purpose of equipping the 
emergency spare tire is to temporarily deal with an emergency case. Thus, 
the durability of such an emergency tire is poor as compared with the 
usual tire, so that it is not desirable to use the emergency spare tire 
practically for a long time. However, while using a motor vehicle, it 
sometimes happens that the driver has forgotten the use of the emergency 
spare tire after replacing the punctured usual tire by the emergency one, 
or that a relief driver is left uninformed of the use of the emergency 
spare tire. This is very dangerous when considering the poor durability of 
the emergency spare tire. 
SUMMARY OF THE INVENTION 
Therefore, it is an essential object of the present invention to provide a 
warning system which can solve the above-mentioned problem. 
According to the present invention, there is provided a warning system 
which comprises a detecting device mounted in a spare tire containing 
recess for detecting whether the spare tire is or is not present in that 
recess; and a warning device electrically actuated by the detecting device 
in a manner to provide a warning when the detecting device detects absence 
of the spare tire in that recess.

DETAILED DESCRIPTION OF THE INVENTION 
Referring to FIG. 1, there is shown a baggage compartment of a motor 
vehicle. A floor panel 10 of the baggage compartment is formed with a 
circular recess or tire container 12 in which an emergency spare tire 14 
is contained or laid down. The diameter of the recess 12 is essentially 
the same as that of the tire 14, so that the tire 14 can be snugly and 
neatly received in the recess 12. In other words, the usual tires can not 
be received in the recess 12 because of the dimensional difference 
therebetween. Designated by numeral 16 is a circular lid which is 
removably connected by a connecting bolt 18 to the floor 10 to cover the 
recess 12 with the tire 14 therein. The leading end of the connecting bolt 
18 is engageable with a tire absence detector in a manner as will be 
described herein next. 
The tire absence detector is shown by FIG. 2, as being generally designated 
by numeral 20A. The detector 20A comprises a hollow body 22, constructed 
of insulating material, which is securely mounted on the central portion 
of the bottom of the recess 12. The body is formed at its upper wall 
portion with a threaded bore 22a with which a threaded end portion 18a of 
the connecting bolt 18 is engageable. Thus, screwing the connecting bolt 
18 into the bore 22a to a certain extent induces a tight connection of the 
lid 16 to the floor panel 10. Designated by numeral 14a in FIG. 2 is a 
wheel disc portion of the tire 14. Two stationary contacts 24 and 26 are 
fixed to the inside surface of the body's upper wall at opposite positions 
with respect to the bore 22a. One of the contacts 24 and 26 is connected 
(or earthed) to the floor panel 10 through a lead wire 28 which is 
partially embedded in the body 22. The other contact 26 is connected in 
series through a lead wire 30 to an ignition switch responsive switch 32, 
an electric power source 34 (battery) and a warning lamp 36 in this order, 
one terminal of the lamp 36 being earthed as shown. The switch 32 closes 
when an ignition switch (not shown) assumes its ignition position for 
running the engine. Within the body 22 is disposed a movable contact 38 
having sufficient size to contact simultaneously both of the spaced 
stationary contacts 24 and 26. The movable contact 38 is biased to move 
upwardly, that is, toward the stationary contacts 24 and 26 by a 
compression spring 40 disposed in the body 22. The movable contact 38 is 
formed at its middle section with a small opening 38a which is engageable 
with a pointed end 18b of the connecting bolt 18. It is thus to be noted 
that when the connecting bolt 18 is engaged with the bore 22a, the movable 
contact 38 assumes its OFF-position (indicated by a solid line), while, 
when the bolt 18 is removed from the bore 22a, the movable contact 38 
assumes its ON-position (indicated by a phantom line) thus connecting the 
two stationary contacts 24 and 26. 
When, in operation, the connecting bolt 18 is kept engaged with the bore 
22a of the tire absence detector 20A with the emergency spare tire 14 
received in the recess 12, the movable contact 38 is kept separated from 
the stationary contacts 24 and 26 the reason as mentioned hereinabove. 
Thus, under this condition, the warning lamp 36 does not operate even when 
the ignition switch assumes its ignition position. When, upon an emergent 
requirement for the tire 14, the connecting bolt 18 is disengaged or 
removed from the detector's body 22 for taking out the tire 14 from the 
recess 12, the movable contact 38 is brought into contact with the 
stationary contacts 24 and 26 by the action of the spring 40. Thus, in 
this condition, the warning lamp 36 operates to give a warning as long as 
the ignition switch assumes its ignition position. Usually, in an 
emergency case, the connecting bolt 18 is let alone in the baggage room 
after removal of the spare tire 14. Thus, the driver is compelled to drive 
the vehicle with the warning given by the warning lamp 36 until the 
emergency spare tire 14 is replaced with a usual tire. Thus, a dangerously 
long drive with the emergency spare tire 14 can be avoided in accordance 
with the present invention. 
Another tire absence detector is shown by FIG. 3, as being generally 
designated by numeral 20B. This detector 20B is designed to detect the 
absence of an emergency spare tire 14 which is contained in the baggage 
compartment, standing vertically as indicated by phantom lines in FIG. 1. 
For stationarily holding the tire 14, the recess 12' is formed into a 
crescent shape. The detector 20B comprises a hollow body 22 constructed of 
insulating material which is securely mounted to the bottom of the recess 
12'. The body 22 is formed at its upper wall portion with a bore 22a 
through which a shank portion 42b of the after-mentioned actuating member 
42 loosely passes. Two stationary contacts 24 and 26 are fixed to the 
inside surface of the body's upper wall at opposite positions with respect 
to the bore 22a. These contacts 24 and 26 are connected through respective 
lead wires 28 and 30 to the floor panel 10, an ignition switch responsive 
switch 32, an electric power source 34 and a warning lamp 36 in the same 
manner as in the case of FIG. 2. The actuating member 42 has a tire 
supporting portion 42a projected outward from the bore 22a and a spring 
seat portion 42c located in the body 22. A movable contact 38 is attached 
to the upper surface of the spring seat portion 42c to be movable 
therewith. The actuating member 42 is biased to move upwardly, that is, in 
a direction to bring the movable contact 38 into contact with the 
stationary contacts 24 and 26 by a compression spring 40 disposed between 
the spring seat portion 42c of the actuating member 42 and the bottom of 
the body 22. It is thus to be noted that when the emergency spare tire 14 
is kept in the recess 12', the actuating member 42 assumes its lowermost 
position permitting the movable contact 38 to assume its OFF-position 
(indicated by a phantom line), while, when the emergency spare tire 14 is 
absent from the recess 12', the actuating member 42 assumes its uppermost 
position permitting the movable contact 38 to assume its ON-position 
(indicated by a solid line). Thus, when the emergency spare tire 14 is 
under practical use, the driver is compelled to drive the vehicle with the 
warning given by the warning lamp 36. 
As is understood from the above, in accordance with the present invention, 
the dangerous long driving time with the emergency spare tire can be 
avoided.