United States Patent
`1191
`1451 July 6,’ 1976
`Tomecek et al.
`
`[11]
`
`3,967,863
`
`
`
`[54] BRAKE CONTROLLER AND SHORT
`CIRCUIT PROBE DISCONNECT
`"
`
`[75]
`
`Inventors: Jerry J. Tomecek, Milford; Philip J.
`Hagerty, Marshall, both of Mich.
`
`[73] Assignee: Tekonsha Engineering Company,
`Tekonsha, Mich.
`
`[22] Filed:
`
`Dec. 9, 1974
`
`[21] Appl. No.: 531,171 _
`
`[52] us. Cl. .............................. 303/24 C; 188/3 R;
`188/112; 303/7; 303/20
`Int. Cl.2 ............................................ 360T 8/16
`[51]
`[58] Field of Search ................ 188/3 R, ‘181 A, 112;
`303/3, 7, 15—17, 20, 21 CG, 24 A, 24 C;
`- 250/215
`
`[56]
`
`References Cited
`UNITED STATES PATENTS
`
`,
`
`2,032,177
`3,497,266
`3,499,689
`3,779,612
`
`2/1936
`Logan, .lr.......................... 3‘03/24 A
`
`2/1970 Umpleby ................... 303/3
`
`3/1970 Carp et a1. ......
`303/21 CG
`12/1973
`Tschannen .................... 303/24 A x
`
`Primary Examiner—Stephen G. Kunin
`vAttomey, Agent, or Firm—Miller, Morriss, Pappas &
`McLeod
`
`ABSTRACT
`[5 7]
`A control for brakes in trailer vehicles comprising a
`circuit providing pulsed signals to the brakes. It is pre-
`ferred that the time or width of each pulse is equal but
`the frequency of brake pulsing is increased in accord
`with inertially sensed stress. The frequency of signal is
`directly related to the movement of a dampened canti-
`lever beam which normally blocks the passage of light
`to a light sensitive target or monitor but wherein the
`passage of light increases and is attenuated by the
`beam as the beam moves, under inertial imbalance, to
`permit added light to be sensed. In addition, the con-
`trol circuit, vulnerable to short circuits in the vehicle
`circuit from control element to brakes, is continuously
`monitored by a disconnect element which senses the
`existence of the short circuit and accomplishes a dis-
`abling of current
`through the control circuit at a
`threshold to avoid injury to the control circuit. An
`electromagnetic coil surrounding a reed switch ac-
`complishes the circuit disconnect in a manner timed
`by a capacitance in the reed switch line. The probe
`disconnect timed pulse acts on an indicator visible, au-
`dible or tactile to the user of such controls and this in-
`termittent signal indicates the presence of a short cir—
`cuit requiring correction before the normal operation
`of the control system can be restored.
`
`3 Claims, 6 Drawing Figures
`
`r.-__
`IL/G/Ir
`“SH/7'6”
`
`I L
`
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`srop
`LIGHTS
`
`
`
`
`
`Curt - Exhibit 1009 - 1
`
`Curt - Exhibit 1009 - 1
`
`

`

`US. Patent
`
`July 6, 1976
`
`Sheet 1 of2
`
`3,967,863
`
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`BRAKES
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`STOP LIGHTS
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`
`BRAKES
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`
`Curt — Exhibit 1009’ — 2
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`Curt - Exhibit 1009 - 2
`
`

`

`US. Patent
`
`July 6, 1976
`
`Sheet 2 of 2
`
`3,967,863
`
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`Curt - Exhibit 1009 - 3
`
`Curt - Exhibit 1009 - 3
`
`

`

`3,967,863
`
`5
`
`2
`light sensitive transistor or inertial displacement of the
`beam.
`Another object is to utilize a relatively simple power
`transistor as contrasted to earlier brake controls using
`complex and expensive Darlington transistors for
`power conduction, for example
`Another object is to provide a continuous and prob-
`ing disconnect which senses external short circuits or
`amnerage surges beyond the brake operational thresh-
`" old and intermittently disables the control until the
`short circuit is eliminated. Then the control circuit is
`automatically restored. This probe includes a signal, as
`for example, a visible light flashing.
`Still another object is to improve the brake control by
`コutilizing and generating a brake pulse of constant width
`but varying frequency.
`Other objects including gain adjustment and sensitiv-
`ity adjustment by tilting the cantilever element will
`nbecome better understood as the description proceeds
`
`BRAKE CONTROLLER AND SHORT CIRCUIT
`PROBE DISCONNECT
`The present invention is directed to a new, simplified
`and improved inertially actuated control structure for
`brakes on trailer vehicles, and especially electric
`brakes. The present invention also contemplates a dis-
`connect safety probe which operates concurrently with
`the brake control unit so that any short circuit outside
`of the control circuit is sensed; the control circuit is
`disabled; and the presence of the short circuit is sig-
`naIled to the driver or user. On restoration of the cir-
`cuit as by correction of the short circuit, the signal
`indicates proper operation and the control circuit is
`restored. The control structure may be positioned in
`the towing vehicle and operative from the ignition and
`generator battery system thereof, or it may be located
`in the trailer or towed vehicle. In the latter instances, a
`direct current power source is connected to the control
`structure as extended from the towing vehicle or sepa-
`rately provided as by a battery located in the trailer.
`
`Background
`
`General Description
`In general, an enclosure is provided which contains
`the inertially sensitive apparatus, the light sensing and
`In a very general way, the present invention is a sub-
`くsignal amplifying and oscillating equipment, wherein
`2
`stantial improvement over the Towed Vehicle Electric
`Jthe gain is adjustable with manual override; the means
`Brake Control as filed on July 27, 1974 by Rene E.
`to adjust gravitational sensitivity is provided; and
`Pittet, et al in the United States patent application Ser.
`wherein the lighting of a signal light indicates the func-
`No. 385,102, now U.S. Pat. No. 3,909,075. The object
`tional character of the hook-up. The control element is
`in the present application is to provide an electronic
`nconnected to a source of electrical power having suffi-
`3
`switching structure which senses deceleration or iner-
`vcient amperage to actuate electrical brakes or sole-
`tial imbalance; translates the imbalance quantitatively
`noids for actuating pneumatic or hydraulic responses
`to a pulsed signal of regular width and variable fre-
`for braking, for example; The controller is also con-
`quency useable at the brakes; and provides a c ontinu-
`nected to the trailer brakes. A probe circuit is superim-
`ously operable short circuit probe preventing injury to
`35posed on the control circuit and continuously monitors
`the control by reason of external short circuits.
`the current conditions to the brakes, and circuitry ex-
`The closest art considered in the preparation of this
`ternal to the control circuit. Ip the probe circuit, a
`application by the applicants is represented in the U.S.
`surge of amperage over the normal brake requirements
`Pat, No. 3,779,612 to Hans Tschannen which describes
`and characterizing a high amperage demand (as occurs
`an unpulsed brake control structure; U.S. Pat. No.
`40 with a short circuit) closes a disconnect reed switch
`3,497,266 of Kenneth F. Umpleby directed to an over-
`timed by suitable capacitance. Closure of the reed
`ride pulsedジ誉讐・manual以磐繋ed in am讐ivibra-
`switch disables the power to operate the brake circuits
`tor circuit, u・，・rat.馴0・i,' JJ,t5y to K aipn w ・しarp,
`and restores the operation when power demand nor-
`et al which senses wheel deceleration and adjusts air
`malizes. If the overload persists, then so long as it per-
`brake response in avoidance of skidding; U.S. Pat. No.
`5 sists the probe tests at timed intervals for exploration
`2,032,177 to John W . Logan comprising a fluid pres-4
`and discovery of the existing defect. The consequent
`sure brake control using a pendulum-like deceleration
`time interval results in a series of spaced power spikes,
`sensor physically closing a switch structure; and U.S.
`each having rapid decay so that the components are not
`Pat. No. 3,486,799 to Herbert Greentree in which pro-
`destroyed or damaged.
`portional deceleration is imoarted to the trailer brakes
`0 The controller may be located in the towing or towed
`and in which there is a dampened inertial sensor.
`5
`vehicle and positioned so that inertially sensitive light
`The present invention distinguishes over these refer-
`interrupting opportunity is displaceable upon decelera-
`ences in providing a simplified electronic control cir-
`tion of the vehicles. In the preferred embodiment the
`cuit; a cantilever type dampened beam inertial sensor
`controller is operationally activated upon application
`including a light quantum sensor adjustably calibrated; -
`5 of the brakes in the towing vehicle so that the brake
`a constant light source with beam interrupted light5
`signal energizes the system. As will be seen,'accelera-
`emission; and a continuously operative short circuit
`tion will not activate the trailer brakes. A light source is
`probe in protection of the control circuit. The probe
`continuously operated when the controller is operating.
`circuit assures an added safety dimension to users.
`A light sensitive element is located in the path of pro-
`Further, the use of a constant width variable freuuencv
`0 jected light and that path is interrupted by a barrier
`pulse is believed to assure better trailer braking without 6
`formed as a part or extension of a cantilever beam. As
`danger of lock-up of the brakes as occurs in systems
`braking occurs, varying the inertia to the beam, the
`which increase the length of each pulse as is known in
`beam is deflected proportional to the degree of inertial
`the prior art.
`imbalance and the light can reach the target of the light
`Accordingly, the principal object is to provide an
`
`improved and safer simplified brake control at lower 6 5 sensitive element in amounts depending on the dis-
`placement. The more displacement (as by a sudden
`cost using a simple light emitter such as a bulb as a light
`stop) the greater the light and the greater the signal
`source and a light sensitive element and wherein a
`from the photosensitive emitter. The cantilever beam is
`:simple dampened cantilever beam gates the light to the
`
`Curt - Exhibit 1009 - 4
`
`

`

`3,967,863
`
`3
`4
`dampened in avoidance of reactance to normal vibra-
`operational simplicity and the light lines indicating the
`tional activity.
`points of integration with the power circuit.
`The variable signal is amplified and pulsed to exer-
`FIG. 6 is a graph of the pulsed signal at a fixed amper-
`cise control over the power circuit leading to the
`age level for braking the towed vehicle and as influ-
`brakes in the towed vehicle. In this manner a pulsing of
`enceu ny a snort circuit manipuiatea ny tne prone to
`the braking power occurs in which each pulse has an
`relieve the control circuit in prevention of damage or
`equal width but the frequency of the pulses is propor-
`destruction. The graph is of time versus amperage or
`tional to the degree of inertial imbalance. The more
`load but is undimensioned in order to represent the
`sudden a stop, for example, the higher the frequency of
`pulsing and probe signal disconnect.
`10
`the pulsing. This signal utilization simplifies the elec-
`SPECIFIC DESCRIPTION
`tronics and as an effective braking pulse the resulting
`In FIG. 1 the controller 11, containing a ‹ dampened
`action of the brakes results in smoother assist stopping
`in the towed vehicle with minimum skidding potential
`cantilever beam element 12, is mounted in a vehicle 13
`and minimum chance for locking of the brakes as is
`which vehicle 13 is shown as towing the trailer 14. The
`1
`characteristic in systems which merely increase brake
`5 vehicles 13 and 14 are connected at the hitch connec-
`pressure・
`tion 15. The controller 11 is connected to a source of
`In the present invention the sensitivity or operation
`power shown as the battery 16 by a power lead 17 and
`threshold of the cantilevered beam is adjustable by
`output lead 18 runs to the brakes 20. The lead 19 cx-
`manually varying the rest position of the cantilever
`tends from rower source 16 via a brake switch 19a to
`2
`beam support structure and gain or threshold level of
`0 the stoplights 21 and the operation of brake switch 19a
`power is adjustable by a manually operable element. A
`The arrow shows the normal forward direction of the
`separate control attached to a manual control lever and
`vehicles 13 and 14 and the hidden edge line indicates
`switch provides a manual override function indepen-
`that the cantilever beam 12 deflects under inertial im-
`ー balance in the path of motion of the vehicle and in the
`dent of the performance of the cantilever beam.
`うnormal forward direction of motion. As will be seen,
`A probe circuit monitors the pulsed performance to
`external circuitry as for example to the brakes and
`the beam 12 can be varied in position to adjust the
`apparatus incidental thereto. In the event of a sudden
`threshold of light transmission.
`amperage surge, above the operational threshold of the
`Referring to FIG. 2, the controller 11 houses the
`braking pulses, the probe circuit provides a timed fre-
`sensor assembly 22 containing the cantilever beam 12.
`quency disconnect at a frequency which disarms or
`0 a light source and a light sensing element; an amplifier
`disables the short circuit from damage or destruction to
`and oscillator circuit 24; and power circuit. 23. The
`the control circuit and simultaneously signals (as by
`tilting of the sensor 22 is represented as a sensitivity
`visible signal) that a short circuit is present. This inter-
`adjustment of the controller 11 upon installation and
`rupts power flow to the load until the short circuit is
`this is schematically represented by the hidden edge
`corrected. Thereupon, the control is automatically
`5 lines. The signal generated by the light sensitive ele-
`operationally restored and power flows. The control as
`ment in the light quantum sensor 22 is amplified and
`described provides improved braking performance; is
`oscillated in suitable circuits to pulse the power circuit
`proof against destruction by external short circuitry;
`23. The amplification and oscillating means 24 are 'a
`and brings simplified wiring safety and lower cost to
`part of the total controller 11. A probe circuit 25 is
`towed vehicle brake controllers. The efficiency of this
`0 superimposed in the control of the power circuit.23 and
`controller is believed to be higher than previously
`monitors the condition in the load circuits or external
`known units and the minimum heat generating charac-
`connections beyond the controller 11 as represented in
`teristics allow resin cases and supports.
`the brakes as schematically shown. The controller 11 is
`- seen connected to the power source 16 such as a direct
`The Drawings
`うcurrent source as a battery.
`FIG. 1 is a schematic elevational representation of a
`En FIG. 3 the dampened cantilever beam 12 is shown
`towing and towed vehicle and in which the present
`in its housing 26. The beam 12 is comprised of a lami-
`invention is located in the towing vehicle with its damp-
`nate of sheets 27 and 28 of beryllium copper forming a
`ened cantilever beam displaceable in the direction of
`sandwich with an intermediate layer of thin viscous
`normal forward movement of the vehicles and exercis-
`0 elastomeric material 29. The lower end of the beam 12
`ing control to the brakes of the towed vehicle.
`is weighted and jacketed, the weight 30 being clamped
`FIG. 2 is a schematized diagram of the present inven-
`onto the beam 12 by the jacket 31 which includes a
`tion and indicating its operational aspects in control of
`tailpiece 32 which acts as a shutter. In one direction the
`the brakes in the towed vehicle.
`- beam 12 cannot deflect because it rests against the
`FIG. 3 is a somewhat stylized perspective cut-away
`"buttress 33 in the housing 26 as an integral part of the
`view of the dampened cantilever beam in its movable
`housing 26. The sheets 27 and 28 forming the beam 12
`housing and indicating the direction of deflection of the
`are splayed, as shown, at the top and this supports the
`cantilever beam to allow light to strike a photosensitive
`beam 12 in a slot 34 formed in the housing 26. The
`.
`element.
`- beam 12 is capable of dampened deflection forwardly
`6
`i FIG. 4 is a circuit diagram indicating the control
`0 in the direction of the, arrow and as indicated by the
`circuit as contained in a space of less than 1 inch by 4
`broken line. As the beam 12 deflects the shutter ele-
`inches by 5 inches with leads to power connection,
`ment 32 moves also. When the shutter element or tail-
`brakes, lights and ground and schematically indicating
`piece 32 moves, as under the influence of inertia, a
`the light interrupting position of the dampened cantile-
`light source 35 mounted in the housine 26 can "see"
`6
`ver beam and the encasement, not shown, may be of
`' into tne winoow jO anu register its rays on tne onoto-
`resin construction.
`sensitive monitor eiement .11 socKeteci in a suitanie
`FIG. S is a circuit diagram extracting the probe ele-
`aperture in the housing 26. Thus, the action of the
`ments from the circuit as seen in FIG. 4 to reveal its
`shutter 32, under inertial influence, attenuates the light
`
`Curt - Exhibit 1009 - 5
`
`

`

`3,967,863
`S
`6
`三製nst 三9verse voltage spik邸や甲the 加ad・勲ed甲り？
`passing from the light sourceI 35 to the light quantum
`jo-is a uioue across' e controtcircuit. itnes 翌 ana ou
`sensor or monitor element 37 cOnsidered inthetotal
`assembly 22. The light from the source 35 is direction-
`anti proviues -protection against transient vottage ror
`司ized by the window 36 toward the target or monitor
`transistor 48- and integrated circuit 49.
`37. The housing 26, preferably cast from- a durable and
`i ne resistance- oi is a current itmiting resistor, oe-
`suitable resin includes:-」 the base portion- 38: which in-
`tween the integrated, circuit 49 and transistor 48 and
`cludes the socketing for the bulb 35 and photosensor or
`acts.as a protective resistance as does the resistance 62
`monitor 37; the apertures for the shutter 32 and win-
`between the line 59 and the integrated circuit 49. The
`dow 36; the shaft extensions 39; and the integral turn-
`L ener etement o. in cooroination witn tne resistance
`1
`ing knob 40. The knob 40 is serrated peripherally and
`" o'e serves voitage to--- tne tamp i' at a constant level.
`the serrations 41 are impingeable on the spring element
`The resistance 64 is located between the lamp 35 and
`42 engaged against the serrations 41 in リ resistance to
`ground line 60.
`rotation of the knob 40. Since the housing 26 is mov-
`In the FIG. 4 the connectors 76, 77, 78, and 79 pro-
`able by the coordinate movement of knob 40 the・ canti-
`vide the necessary connections to integrate the control-
`lever beam 12 can be caused to separate selectively
`5 Icr 1! with, for example, a 12 volt DC' current automo-
`from the housing back 3-3 so as to adjust the amount of
`bile ignition system and electric brakes. The connector
`light and time of light emitted to the target 37. As light
`76 links the controller 1! with the power source 16.
`passing to the photosensitive element 37 increases be-
`The connector 77 plugs into the brake load. The con-
`yond a threshold setting, the signal from the photosen-
`nector 78 grounds the controller. The controller 79
`sitive element 37 increases. The・ rotation of knob 40
`2
`0 shows the control connection to the stoplight switch in
`permits the selection of an operational threshold. Trun-
`a schematic sense because the stoplight switch is oper-
`nion means, not shown, cradle the shaft extensions 39
`ated upon application of the brakes of the towing vehi-
`cle 13 and either一 this action or manual override, as
`inthe controller 11. Combined, this described grouping
`is the light sensor assembly 22. ・
`described is needed for automatic cOntrol. It will be
`2
`In FIG. 4 the circuit served by the sensor assembly 22
`5 understood in the circuits as shown in FIGS. 4 and 5
`is best understood since the shutter 32 on the beam 12
`that grounding is to the- -frame of the vehicle as for
`is in an interruption path between the light source bulb
`example, the chassis as is typical in automOtive c ir-
`35 and the (photosensitive) target 37. When inertia
`cuitry.
`causes deflection of the beam 12, as by braking of the
`Referring to FIG. 5, the probe circuit 25 is shown
`3
`towing vehicle, light is transmitted dependent upon the
`0 extracted from the controller circuits but better illus-
`magnitude of inertial imbalance and as will be seen, the
`trating the coil 65 in the power line 18 to the- brakes
`light generated signal is amplified and oscillated to
`which magnetically surrounds the reed switch 66. In
`create a pulsing of the silicone power transistor44. The
`theFIG. 4 this was shown by the heavy dashed line
`source of power, such as battery 16, is connected to the
`extending from reed switch 66 to the coil 65.
`3
`controller 11 and the power is transmitted in pulses to
`5 The power bus 59 is shown-at connection to the lamp
`74 in-the probe circuit 25 and the line 75 bridges to」 the
`the load or brakes 20 when light is transmitted by the
`inertial sensing of the' light quantum sensor 22. Actu-
`output of the integrated circuit 49 adjacent to resis-
`ally, a selected loadI current in this system is fed to the
`tance 6!.
`load at all times of operation at a level to allow smooth
`- By reference to FIG. 6, the short circuit-probe is best
`4
`transistion to stop, as will be seen. The controller!! is
`0 UnderstOod. The regular or uniform width brake pulses
`activated by manual override, as will be see一n, and/or by
`80 are shown'schematically at a near-maximum fre-
`the actuation of the vehicle stoplight switch outside the
`quency and delivering an amperage load for-the time tt
`controller and designated in phantom line.
`as indicated by the work load amperage level 81, say 1-5
`L
`anlDS.
`A manually operated switch 45 is also a part of the
`4
`5 When a load in excess of the work load is sensed by
`potentiometer 46 so that a manual override is possible
`」by impressing a signal on the circuit independent of the
`the probe circuit 25, then a spike 82 occurs in the pulse
`action of the light sensor 22. The potentiometer 47 is a
`form with a rapid almost instantaneous decay from the
`gain (maximum power threshold) adjusting potentiom-
`spike to zero amperage and holds at zero amperage for
`eter. The gate to the power transistor 44 is via the
`- the time period i t, as determined by the capacitance
`5
`0 67. This interval (selected at about 1 second) avoids
`transistor 48. A multiple lead integrated circuit 49
`overheating of the circuit and in tests has protected the
`vastly simplifies the circuitry required and the pre-
`control circuit in the controller 11 for extended periods
`ferred integrated circuit 49 is commercially designated
`as 555 or equivalent to achieve pulsing to a constant
`in excess of 68 hours with a short circuit in the load
`line.
`width signal or pulse with variant frequency. The
`5
`5 Closure of reed switch 66 takes the junction of Ca-
`changing capacitor 50 with the diode 51 and resistance
`52 limits the duty cycle and in conjunction with the
`pacitor 67 and base of transistor 68 to ground line 60
`variable resistances determines the pulse rate of the
`via resistance 53. Then transistor 68 takes the junction
`72 to ground 60 via line 71. This action causes inte-
`integrated circuit 49. The low value stabilizing capaci-
`tor 50a is located outside of the integrated circuit 49
`grated current 49 to cause transistor 48 to cause power
`6
`0 transistor 44 to turn off. When power transistor 44
`and is connected thereto on one side and to the base or
`turns off current flow in line 18 is reduced to zero.
`ground 50b on the other side between the integrated
`Then coil 65 no longer having current flow allows the
`circuit 49 and ground line 60. The capacitor 50a in-
`reed switch 66 to open. Then transistor 68 starts to
`sures positive switching of the integrated circuit 49.
`dimension conduction at a time denendent uvon the
`A resistance 53 is positioned on the line 54 to ground
`-' cnarge on capacitance bI・ I flls, in etrect, creates a time
`6
`55 to tie down the collector of driving transistor 48 and
`interval A t1, such that the conduction of transistor 68 is
`the base of the power transistor 44 to insure proper
`reduced to zero and the integrated circuit 49 causes the
`operation and also functions as a part of the probe
`transistor 48 to cause power transistor 44 to resume
`circuit as will be seen. Diode 56 protects, with diode 57
`
`Curt - Exhibit 1009 - 6
`
`

`

`3,967,863
`
`7
`8
`power to the load 20. If amperage-requirement is such
`ing and cool operation allows the use of a resin housing
`at substantial cost reduction.
`that the coil 65 is reactivated, then the cycle is repeated
`Having thus described our invention and one pre-
`providing intermittent spikes having an interval of it1
`ferred embodiment thereof in substantial detail, others
`as will be seen in FIG. 6. The spikes and interval be-
`5 skilled in the art will" appreciate modifications, changes
`tween spikes is non-detrimental to the system while
`and improvements therein and, such modifications,
`allowing constant monitoring of the short circuit until
`changes and improvements are intended -to be included
`the short circuit is removed, whereupon the controller
`herein limited only by the scope -of the - hereinafter
`11 automatically resumes normal operation.
`appended claims.
`The signalling function of the probe circuit 25 which
`10 We claim:
`provides a visual, tactile or audible warning of the bath
`1. A brake control system for brakes in towed vehiー
`operation and malfunction as by external short circuits,
`dIes and connected- to a source of electrical energy
`is also appreciated in the FIG. 4 where the lamp 74 is
`comprising:
`shown. At the instant that junction 72 is connected to
`a light sensitive monitor;
`ground 60 through line 71 and transistor 68, current
`15
`inertially operated and adjustably positioned damp-
`flow from power line 59 through lamp 74 and diode 70
`ened cantilever beam attenuating light to said mon-
`will cause the light 74 to illuminate. As transistor 68
`itor;
`allows less current to flow, the lamp 74 extinguishes.
`a pulsed power circuit controlled by said monitor,
`This results in intermittent signalling or flashing of the
`said circuit transmitting upon actuation a constant
`light 74 as the reed switch 66 opens and closes at the
`width pulse at a - frequency proportional to the
`△t1 interval.
`amount of attenuation of the sensed light as deter-
`During normal operating the lamp 74 is illuminated
`mined by said inertially operated beam; and
`at an intensity level caused by the pulse rate of the
`brakes in a towed vehicle operably connected to said
`integrated -circuit 49 through diode 69. Hence, the
`nulsed nower circuit.
`illumination is equal to the frequency of the power
`25
`2. 1 he combination as set torth .in claim I in wflicfl
`pulses as influenced by the light sensing inertial struc-
`the pulsed power circuit includes a gain control circuit
`ture and the -illumination is also influenceable in the
`adjusting the threshold of power-to said brakes.
`same way by manual override.
`3. A brake control system for brakes in towed vehi-
`In operation, the controller 11 of the present'inven-
`des connected to a source of electrical energy compris-
`tion provides a safer brake control for towed vehicles
`30 ing:
`and in which a pulsed signal activates the brakes in the
`an inertially operated dampened cantilever beam;
`towed vehicle responsive to the action of a sensitive
`a source of light on one side of said beam;
`dampened caiitilever beam. The circuits, as described,
`a light responsive signal generating element on the
`are extremely simple and amenable to reduced cost and
`other side of said beam, and the output of said
`are protected against damage from external defects by
`35
`generating element being attenuated by -the posi-
`a discriminating and continuing probe and circuit -dis-
`tion of said beam;
`abler. A resin casビ can be employed. Connectors for
`a power circuit gated by said light responsive ele-
`circuit integration at power source, load, and ground
`ment, said power circuit providing-a constant width
`are reasonably simplified in prevention of errors and if
`pulse, the- frequency- of. said- pulses -being directly
`40
`errors in' installation are made the controller 11 reacts
`proportional to the increase in light as received by
`by applying thと brakes fully with the indicator lamp at
`said light responsive element; and -
`full strength or by -being inoperative or probing and
`brakes in said towed vehicle operably -connected to
`disabled, as described. The full lamp and full braking
`said power circuit.
`* *. :*.
`occurs if the ground is inadequately made. The ground-
`
`20
`
`45
`
`50
`
`55
`
`60
`
`65
`
`Curt - Exhibit 1009 - 7
`
`*.
`