Note: Descriptions are shown in the official language in which they were submitted.
CA 02209158 1997-08-01
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FINAL DRAW
~ CA 02209158 1997-08-01
WHEEL DISCONNECT ALARM
TABLE OF CONTENTS:
2.... ... .... Purpose
3.... ..... Major Apparatus
~ 4. .......... Operation
4............ .A/ Circuit Continuity
4........... Bl/ Bearing Failure - ALARM with circuit continuity
4. .. . . B2/ Bearing Failure - ALARM without circuit continuity
5.. . .. C/ Loose Wheel Bolt - ALARM
6.......... . NOTES
7. . ...... Sketch A & Sketch A1, Heat Monitoring Circuit
8... . ... Sketch B, Wheel Bolt Monitoring Circuit
~ 9. ......... Sketch C & Sketch C2, Wheel/Bolt/Switch Arrangements
10.......... Sketch D & Sketch D1, Wheel, Bolt/Switch Arrangements
11..... . . Sketch E, Typical Transceiver & Typical Placement
ll
CA 022091~8 1997-08-01
WHEEL DISCONNECT ALARM
PURPOS~
nle purpose of this circui~ is to WARN the driver of the vehicle using alarm devices that will
detccl in advancc, a possible "Wheel Disconnection". This wheel disconnect alarm will detect
eithcr of thc rollowing conditions:
1. A pending 'whecl disconnection' caused by bearing failure (Inner or Outer) occurring inside
the axle of Ihe vehicle (Sketch D & Dl).
Major causcs of bearing failure are bearing fa~igue (age/wear), overloads, and loss of lubricant.
Oil seals or lubricant housings break because the dual whcels are often dragged around comers
(tight comer slippage), maneuvered over street curbs and large roadway holes, etc. This housing
breakagc allows thc lubricant to escape causing the bearing to overheat, then fail. In these
instances, friction caused from 'bearing failure' creates a large amount of heat on the outside
housing of the axle. Once a certain temperature is reached, the entire dual wheel becomes
dislodged from the axle. Heat sensors are anachcd to a bracelet and then the bracelet is f~q~ten~cl to
the axle housin~ (Inner & Outer) to monitor heat levels, which indicate 'whecl ~ connect'
condilions.
2. A pending 'wheel disconnection' caused from a loose wheel bolt allowing a wheel
to disconnecl from the wheel stud and the axle (Sketch C).
A major cause for a loose wheel bolt is when wheels are subjected to extreme co~ g, to extreme
bumps or poor m~;ntl~n~nce A micro switch or plunger switch is ~tt~hrd to a wheel rim (Ref.
Sketch C). This switch converts the mech~nir~l rel~1ion~hir between a wheel bolt and a wheel stud
into a normally open, elcc~ronic condition, whilc the bolt is securely fastened to the stud. Once the
bolt becomcs loose by one or two turns, contact pressure between the micro switch and the bolt
collar is removed causing the switch to change from an open type switch contact to become a
closed electronic switch contact (Ref. Sketch C2). The closed clectronic switch contact extends an
operating voltage (zero ground) to a transceiver (Sketch C~). The transceiver then encodes a tone
(submits a digital tone) to a receiver located in the monitor alarm unit located near the driver
(Sketch B). This dccoder is used to announce the alarm to alert the driver of the loose wheel bolt
and pending 'whcel disconnect'.
CA 02209158 1997-08-01
MAJOR APPARATUS --
1. 'Heat Sensor Switch' - (Sketch A, Sketch D & Dl)
A Heat Sensor SwiLch is fastened to a bracelet; then each axle housing (Inner & Outer) is equipped
with this bracelel (Ske~ch Dl). The heat sensor switch provides advance detection by monitoring
heat that is created when a bearing fails. The l~lllpeldLure of the heat sensor (a~,l.)xi~ tely
200 - 400 C) is somewhat lower than the actual heat temperature that is responsible for a wheel to
become disconnected. This allows the heat sensor to operate in advance of the actual wheel
disconnection and to warn the driver in advance of a pending 'wheel disconnect'.
2. ' Tr~ iv~, ' - (Sketch B & Sketch E); & 'Micro Switch' - (Sketch C & D)
A Transceiver is connected to a Micro Switch (or the Plunger Switch) and the outer wheel bearing
heat sensor switch. The transceiver, bolt/collar micro switch and heat sensor switch are fastened to
the wheel. (Reference Sketch Cl, C2 & C3).
3. 'Monitor Unit' - (Sketch A & Sketch B)
A Monitor Unit is located inside the vehicle to monitor the activity of both devices listed for 1 & 2
above. An active change in eilher device causes an alarm to alert the driver. The alarm includes
bolh an audible ~piezo buzzerZ) and llashing visual LED (Light F.mifting Diode) . This unit
conlains the following components: (IC = Integrated Circuit)
ICl FL Flasher providing the alarm flashing ground zero volt (-V); type 555.
IC2 - IC6 RS Remote Sensing Switches; type 4066
Z Piezo Buzzer for audible alerl in an alarm.
LED Light F.mit~ing Diode
D Decoder (Receiver)
TR2 Transistor type 4401
RCLl Resistor 330 ohms; 1/4 watt
RF, RE, RS Resistor 220 ohms; 1/4 watt
Dl Diode type II'J4001
~ 3
CA 022091~8 1997-08-01
OPERATION: ¦
ALARM occurs as follows:
A: Circuit Continuity- (Al . ,...~....~--1 for Heat Sensor / INNER Bearing Failure Only)
In a state of rcadiness, each rNNER heat sensor switch (HS) provides a con~inuou~ ground (Zero
Volls) via normally closed switch contacts, to cause an assigned axle (LED) Light F.mit~ing Diode
to illuminale in a nonactive, 'No Alarm' state. The LEDs illllmin~e continuously to indicate
circuit colllilluily, monitoring 'physical wire cormections' only in a fail-safe mode. If by some
mcans a wire breaks or the heat sensitive switch becomes unconnected, the continuous ground
provided by the normally closed heat sensor contact, continuous (HS) ground is removed; ground
short to thc RS switch (IC 1 - IC5, R5/R4 Multiple) allows the RS switch to operate, to provide a
zero voll (-V) ground to allow the operation of the IC1 FL flasher. The FL flasher then provides
a 'nashillg ground through the operated RS swilch contacts to replace the continuous ground
prcviously providcd by the unconnccted heat sensor switch (HS). The flashing ground (from
FL/IC 1 ) causcs the unconnected HS, associated LED to flash off, then on, then off, etc. indicating
an 'Alarm' s~ate. The same zero ground (-V) provided to operate the IC1 (from the alarmed RS
swilch contact) is also extended to operate the Piezo Buzzer (audible alert). Resistors R1 and R2
~letennine the flash tirne (or~off) intervals.
Bl: Bearing Failure ALARM
Heat Sensor Switches -- (Sketch A & Sketch D2) - With Circuit Co--lh~uily
Tlle contac~ within Ihe heat switch is a normally closed switch contact. Once the heat sensor
switch delccts cxcessive heal (created in the axle housing from bearing failure) the heat sensor
switch contact HS open to remove the continuous ground (Sketch A & Sketch D2). With the
continuous ground (-V) removed (~hllnting the assigned remote switch RS), the assigned circuit
connccted RS switch, operates the flasher FL/IC1 (Sketch A, IC2 through IC5). The IC1 flasher
FL then provides a flashing ground (-V) via the operated RS switch contacts to replace the
conlinuous ground (-V) previously provided by the rela~ed heat sensor switch (HS). The flashing
ground from IC1 causes the LED to flash in an Alarm-Slate. The same zero ground (-V) provided
to operale the ICl (Integraled Circuit #I) from the alarmed Remote Switch RS contact, is also
exlended to operate the Piezo Buzzer 'Z' (audible alert). Resistors R1 and R2 determine the flash
time inlerval to operate the LEDs in the Alarm-Slate.
B2: Bearing Failure ALARM
Heat Sensor Switches -- (Sketch Al & Sketch D3) - Without Circuit Conlil-uiLy
-- For both Inner and Outer Bearing Failures
Heal scnsitive switches (HS) are mounted on a bracelet then attached to the axle of the vehicle. The
contact within the heat switch is a mj, Il ally open switch contact. Once the heat sensor switch
detccts cxcessive heal (created in the axle housing from bearing failure) the heat sensor switch
conlact HS close in an alarm condition (Sketch A1 & Sketch D3). This closed alarm condition
extends an operating zero ground (-V) to operate the cnnnect~d transceiver (Sketch E). The
transceiver encodes the alarm to a separate, assigned decoder in the monitor unit the same manner
as describcd for the loose bolt alarm.
CA 022091~8 1997-08-01
C: Loose Wheel Bolt ALARM
Micro Switch / Transceiver - Encoder / Receiver - Decoder
- Micro Switch / Plunger Switch -- Sketch C, Sketch Cl & Sketch C2
A mech~nical micro switch is attached to a wheel rim to electro-me~h~nic~lly convert a
m~ch:~nic~l pressure contact between a bolt fastened with a collar (Ref. Sketch C) and an
associa~cd wheel micro switch into 'circuit logic' as follows:
When a wheel bolt is tightened on the stud of the wheel, 'contact pressure' is applied between the
mechanical switch ~plunger portion of the micro switch mounted with the transceiver and on the
whccl rim) and the wheel stud (Sketch Cl). This tightened mech:lnic:ll 'contact pressure' between
the collar and arm of the micro switch causes the switch to OPI~RATE its' contact in an 'open'
condition (Sketch C). This 'open' condition discormects (removes) an operating voltage, zero
ground (-V) from thc connecLed transceiver. Once a wheel bolt loosens or unwinds one or two
tums, contact pr~ssure applied between the bolt mounted collar and the mechanical switch, plunger
portion of thc micro switch mounted on the wheel rim, is removcd causing the mech~ni~.~l switch
conlacts to R~LEASE in a 'closed' electrical condition (Sketch Cl). This closed condition
extends an operating voltage zero ground (-V) to cause the electrically connected LrallSCt~ivt~l to
aclivalc.
- Tr~ ivel Encoder -- Sketch B & Sketch E
The Transceiver, when made active, is used to encode the loosc wheel bolt and/or wheel bearing
failure by tr~n~mining a digital tone (frequency) to the vehicle-monitoring receiver where it is
decoded as a 'wheel alar n'. Switch closure, as previously described, extends zero ground (-V) to
activate a Transceiver much the same as a regular, everyday hou~çhnld 'garage door' opener
(located in some vehicles) that transmits a special tone to a 'garage door receiver .
A Transceiver is used with Normally Open type heat sensor (HS) switches to rlimin~t~ costly
~ wiring directly to individual assigned axle LEDs (located within the monitor unit). The collLilwily
alarm (having the LED illuminate continuously) is elimin~t~d when the HS switch logic changes
from normally closed to this normally open type . Switch closurc then occurs when the dangerous
~ hea~ is detected during the Alarm-Slate. This closed con(1i~ion extends zero ground (-V) to
operate/activate the electrically cc nnrctt d transceiver.
- Receiver - Decoder -- Sketch B
A Decodcr 'D' (located inside the monitor unit) recogni 7.es the transceiver tone, decodes the tone
and extends an operating voltage (zero ground) to the TR transistor (Sketch B & Sketch C2)
causing the TR transistor to release and RE transistor to operate with the sarne flashing alarm
procedure (LED and audio buzzer) as describes for the heat sensor switch, HS operation. A
T ~t~hing zero ground (-V) is provided via IC6, through diode D2 to latch this 'Loose Bolt' alarm
circuit in thc alarm condition. This latching function is provided to replace any momen~ty pulses
lha~ have incurred from 'contact bouncing'. The micro switch connected to the wheel bolt may
experience momcntary open and closures (contact bounce) during the first turn of a loose wheel
bolt alarm. Other occurrences such as a rock impact on the wheel might cause a similar contact
bounce. A push button (LR) switch when operated will disable the momentary type alarm. If the
alarm immediately reoccurs, the alarm is genuine.
~ 5
CA 02209158 1997-08-01
NOTES
1. Multipled thru to circuits 1- 10 and 'LWNC' (Loose Wheel Nut Circuit).
2. Capicator Cl = .01uf.
3. Capicator C2 = 10uf.
4. Reisistors RF~ & RF2 - 22K ohms.
5. Resistors RSl thru RS4 (all desigin~ted RS count) etc, RE4 thru RE5 = 221K.
6. Resisitors RLl thru RL10 & RCLl are .33k ohms.
7. Diodes are type IN4001 or equivalent.
8. Transistor T2 = type 4401.
9. Integrated Circuit ICl = type 555.
10. Integrated Circuits IC2 thru IC6 = type 4406.
11. Connect to each 'RS' (Remote Switch) Mult. of each Circuit IC2 thru to IC5.
12. Latch Release 'LR' is a notmally closed single pole contact switch; pluse type.
