DE19624068A1 - Icing prevention for windscreen wipers - Google Patents

Abstract

The windscreen wipers can be lifted out of contact with the windscreen by a servo drive when a temperature sensor detects freezing conditions. This lifting action operates only when the vehicle is parked ie. with the engine/ignition switched off. When the vehicle is started the system drops the wipers blades back into contact with the windscreen. The system can be fitted to both the front and rear windscreens. The lift off action can be provided by cams linked to a servo motor. Alternately the lifting action can be provided by the end stop controls for the wiping action, with a servo drive to lift the stops and the wipers. The freezing point is determined by the setting on a Zener diode in the control circuit.

Description

The invention relates to an automatic lifting device for motor vehicle windshield wipers, which only functions when stationary with an external frost climate.

So far, it was common to use the windscreen wiper blades when parking vehicles below Lift the freezing point manually from the respective pane surfaces so that potentially not being able to travel with them.

This process takes a little time and is also the case with commercial vehicles such as trucks, buses, and even rail vehicles, because of the high construction height there the windscreen wiper is not exactly easy.

The invention is therefore based on the object of automating this process, so that the windshield wipers from Cars themselves can be lifted off without contact with the glass.

This problem is solved by the features in claim 1. Advantageous Embodiments of the invention are characterized in the claims below.

In the automatic lifting device of motor vehicle Windshield wipers, which are only in standstill or when the drive unit is switched off takes effect if the external temperature reaches the 0 ° C limit (freezing point) falls below, the windshield wiper (s) become a minor but sufficient size - automatically lifted from the disc surface (s).

The windshield wiper (s) are actuated by specific cam levers, which are in multiple arrangement by a swivel angle synchronizing Linkage rods are hinged together, that moreover at the same time as a limit switch release element to switch off the controlled servomotor unit / servomotor rotation direction to the specifically defined Swing angle sizes serves / is formed, mechanically levered up and down.

The cam lever (s) are also pressed by (bending) spring pressure after being reset / put on the wipers automatically into the contactless angled cross position returned.

In addition, a specific telescopic mechanism when lifting and lifting the windshield wiper (s) each have a swivel latch on the (s) simultaneously Telescopic wiper arm (s) telescoped along so that when lifted (n) Windshield wiper (s) are passed over the joint recess (s) of the wiper bracket (s), which prevents them from being affected by wind / gravity on one Contact the end piece on the respective pane surface and definitely there with potential anise.

An external one is used to trigger this wiper lift-off function Temperature sensor, for example in the form of a specific PTC resistor (PTC thermistor), which only falls below the 0 ° C temperature setpoint Current voltage applied to a blocking resistor-specific limiter diode (Zener diode) amplified in such a way that their "breakthrough" exactly from the Freezing point occurs, which then definitely a wiper lift-off mode introductory servomotor / electromagnetic thrust actuator controlled and up to one Limit switch contact is operated.  

When the vehicle drive unit is started up, a servomotor is activated simultaneously controlled and operated up to a further limit switch contact, which via a specific lifting mechanism put the wiper (s) back on the windshield (s) resets. In this process, a special circuit technology "Double plus excitation" means switching the current through to the switching relay / switching transistor, which controls the lifting-relevant switching elements, foiled.

The detailed explanation of the structure and function of the illustrated invention is then carried out using the drawings.

It shows

Fig. 1 diagram with circuitry functional course in the control position: "windshield wiper attached" with activated terminal 15 - / + ° C range

Fig. 2 diagram with circuitry functional course in the control position: "windshield wiper lifted" with deactivated terminal 15 - / - ° C mode

Fig. 3 detailed representation of the wiper bracket lock by the wiper arm swivel bar telescopic mechanism, and the positioning (s) of the cam slot recess (s).

In Fig. 1 the diagram with circuit technology function pattern in the control position is "wiper placed" during terminal 15 - / + shown ° C range.

The vehicle battery with the downstream ignition start switch is closed at the bottom left see.

The power supply to the switching relay (in its place e.g. a suitable one NPN switching transistor could occur) is used for both the control and Switch contact lead realized from "terminal 30" (continuous current). of course is this supply line from a correspondingly decimated series resistor in addition to the obligatory Line fuse upstream.

This switching relay would now be due to the permanent supply of operating voltage tighten or bridge the switch contacts and connect the downstream PTC Resistance (PTC thermistor), which is constantly exposed to the external temperature, activate.

This PTC resistor is also the limiter diode connected in parallel (Zener diode) specified such that the precise from freezing point (0 ° C) modulated voltage is amplified so that the diodes "Breakthrough" takes place. With this effect, the electromagnetic thruster servo "1" up to its limit switch contact - triggered due to the control pin of the wiper lifting cam shown in black Linkage linkage - operated, and the wipers would by means Upright position of the lifting cams in the angular position - theirs there The longitudinal axis of symmetry is marked here by the obliquely vertical dash / dot line is - be lifted away from the pane surface.

This slight inclination - see also Fig. 2 - of the elliptical sliding-favorably designed lifting cams is obligatory, since the (tension spring) contact pressure of the raised wiper arms then prevent the cams from tipping backwards (into the starting position).

The hatched horizontal reference plane behind the cams represents the surface plane of the body panel / pane frame specifically provided for the cam pivot recesses - see also FIG. 3.

However, this function mode is generally prevented because the ignition-start switch is in Driving position, where of course the wipers - at whatever outside temperature always -, lying on the disc surface, must be operable, switched and thus also "Terminal 15" (switched plus) activated or in the circuit as active leader is involved.

From this terminal a conductor is branched in parallel, which on the Ground contact of the relay control winding is present and there permanently - while driving - brings about a double plus excitation in terms of circuitry, the relay Switch contacts cannot be tightened.

The thruster servo "1" cannot be effective, even if the external one Temperature would have fallen below the + ° C range (see note below right).

A further branch of this terminal, which carries current during operation, leads via a second limit switch to the electromagnetic thruster "2", which thereby turns on simultaneously when the ignition is switched on until the
Wiper lifting cam linkage on this limit switch (or its push button) is operated.

After that, the briefly telescoped thrust pin returns due to one of the same Thrust actuator "1" - internal return spring in its initial position, since the Power supply of the operating voltage defined by the series resistor through the then permanently open limit switch contact bridge is interrupted.

This contact bridge of the limit switch remains permanently open because the Feedback-relevant spiral springs, which on the pivot pin and on it each rotatably mounted wiper lifting cams are articulated and thereby sufficient torsion-specific torsioning in the one shown here Bring the cam across, with the wiper cam linkage Limit switch push button - as can be seen here - sufficiently acted upon. Now the Ignition switched off again, this automatic wiper lifting system is ready for operation (in focus).

The swivel angle of the wiper lifting cams, which here is determined by the two Dash / dot lines shown depend on the factors: more effective Cam pivoting radius, cam distance to the wiper arm (with transverse cam position) etc. and is to be conceived with the addition of precisely these other parameters in such a way that a sufficient - but not excessive wiper blade distance to the respective front / rear window or headlight glass surface is achieved.

The conceptual example of two oppositely operable shown here electromagnetic thruster servos, which, so to speak Pushing the connecting rod back and forth is by no means to be regarded as imperative, but would be z. B. a two-way electric motor with gear output, especially in the climatic frost period due to frozen condensation, (which is often concentrated / present in the pane area), certainly more prone to failure, and one Functional failures should be dealt with as constructively as possible in this device will.  

FIG. 2 shows the diagram with the functional circuit diagram in the control position: "windshield wiper lifted" with the terminal 15 - / - ° C. mode deactivated. According to this diagram, the ignition is switched off, the otherwise current-carrying conductor with the motor vehicle technical designation "terminal 15" being deactivated; the external climate has also fallen below freezing.

Now the automatic - ° C-related windscreen wiper lifting mode functional escalation.

Since there is no more voltage at the ground contact of the relay control winding (Double-plus excitation canceled), the latter closes its switching contact bridge and thus switches the permanent positive battery current of "Terminal 30" to the external climatic temperature sensor, which is used here as an example as a specific PTC Resistance is formed by.

This temperature value transmitter now minimizes due to the given external Temperature value - in the negative range - its electron resistance in that that the Zener voltage constant of the limiter diode connected in parallel is exceeded and the thruster servo "1" over the switching bridge of his Limit switch is controlled.

This pusher telescopes its peg, and the two Wiper lifting cams lift synchronously - thanks to the side shift Linkage - the two windscreen wiper arms above it and thus indirectly also the wiper blades to a defined extent from the window surface.

The linkage again gives the spring-back push button again closing limit switch of the thruster servo "2" free - see arrow line -, applies its (lower) control pin - but only in this one apparent slight inclination of the lifting cams (which are otherwise the same as Connecting rods not necessarily made of metal, but rather made of weatherproof Plastics z. B. Teflon or carbon fiber reinforced plastic should be made) also spring-loaded pushbutton of the actuator "1", after which its Push pin again because of the related power supply interruption automatically returns to its original position (by internal spring pressure).

The pressure spring force of the wiper arms now presses due to this specific Cam slant the connecting linkage against the thrust plate of the Thruster "2", which thus forms the mechanical lifting stop.

If the driver starts the motor vehicle that integrates this device again after he has possibly cleared the windows from the ice with wipers that have not iced up, the windshield wipers are put back on immediately, since the mode already described in FIG. 1 by the specific double plus -Excitation on the switching relay / switching transistor is given again.

In Fig. 3 the detailed representation of the wiper bracket lock by the wiper arm swivel bar telescopic mechanism, as well as the positioning (s) of the cam slot recess (s) is shown on the basis of specific detailed views ("1-4").

In the drawing field "1", this mechanism can be seen in the functional position: "wiper lifted" with the swivel bar ( 2 ) telescoped out. When lifting, this swivel bolt is lifted by the elliptical sliding tip of the starting lifting cam, which also acts as a sliding element on the underside of the respective wiper arm ( 1 ), by simultaneously pushing the swivel bolt's own push pin ( 5 ) - see also separate swivel bolt side view in drawing field "4" - via the outer, free-standing longitudinal flank ( 4 a) - see again wiper bracket - top view in drawing field 4 - telescoping the swivel joint recess of the wiper blade bracket surrounding the wiper bracket locking tab of the wiper arm.

Thus, the wiper bracket ( 3 ), the relevant upper edge of which is contoured here only by a dash / dot line, is prevented from swiveling movements due to the effects of potential wind / gravity, since the underside of the swivel latch is now aligned with that of the swivel recess flank ( 4 a) on the longitudinal side adjoining surface of the bow frame contacted in such an action to prevent swiveling.

If the wiper-like mounting mode of the windshield wiper (s) is initiated as a result of the start of the journey - as shown in FIG. 1 - then a telescopic pull on a spring hook eye of the respective wiper arm, as well as on an axially located swivel bolt-specific pull pin ( 6 ) - see also drawing field 4 - locked tension spring ( 7 ) the swivel bolt back into its unlocking starting position, whereby it releases the longitudinal side wiper blade side ( 4 a) back. This initial / telescopic position of the swivel lock - with attached wipers - in which the wear-related wiper blade bracket conversion is then possible is shown here in the drawing field "3". The displaceability / telescopability of the swivel bar is made possible by a specifically dimensioned / positioned, centrically axial slot recess of the respective wiper arm, which is indicated here in the drawing field "4" with the pending designation "1".

The pull / push pins ( 5 , 6 ) of the swivel bolt each have therein their guide (radial) recesses, their common guideway, which, apart from the required play tolerance, is congruently dimensioned with respect to height / width. The elements ( 5 , 6 ) could, for example, be riveted or screwed onto the swivel bar - of course if the wiper arm guideway had been carried out beforehand (from inside to outside) - as shown here.

So that it is due to the permanently exposed weather exposure of this mechanism - not too corrosive, especially if the function is not used for a long time (summer operation) conditional jamming, it is recommended here, at least for swivel crucibles, Teflon or carbon fiber reinforced plastic or the like to use as base material. On the other hand, you could also use this sliding element In addition to the wiper arm, coat with these or other plastics.

In the drawing field "2", with reference to a sketched car top view, the wiper arm underside cam pivot recesses ( 8 ) are shown with reference to the respective wiper rotation pivot axes ( 9 ) and the body panel / (front) window frame.

When wiper arm lock, the wiper arms are exactly over this Adjust lifting cams (recesses), as they are otherwise the same Leverage the function trigger "into the void". These recesses must also each have one have the flexible (lip) seal facing the cam, which these Breakthroughs in both cam end positions, even in the short term Cam swiveling movements, against the penetration of water / snow / ice into the internal electromechanical wiper lifting device arranged underneath prevent as much as possible.

Claims (7)

1. Automatic anti-icing of motor vehicle windshield wipers - when stationary - with an external frost climate, characterized in that the windshield wiper (s) are automatically lifted from the window surface (s) only when the vehicle is stationary or when the drive unit is switched off, provided the external temperature is 0 ° C falls below.
When the drive unit is started up, the windshield wiper (s) are immediately put back onto the respective vehicle front / rear windows. 2. Automatic anti-icing of automotive Windshield wipers - when stationary - with an external frost climate characterized, that to trigger the function of the wiper lift-off effect - outside driving - an external temperature sensor e.g. B. in execution of a specific PTC resistor (PTC thermistor) is used, which falls below the 0 ° C The temperature setpoint is only at a standstill Voltage to a blocking resistor specific Limiter diode (Zener diode) amplified so that their "Breakthrough" occurs exactly from freezing, which then definitely actuated a servomotor initiating the lift-off mode and is operated up to a limit switch contact. 3. Automatic anti-icing of automotive Windshield wipers - when stationary - with an external frost climate according to claims 1 and 2, characterized, that simultaneously when starting the vehicle drive unit a servomotor controlled and up to a limit switch contact continues to operate, which has a specific Lever mechanism the wiper (s) back on the Reset disk surface (s). 4. Automatic anti-icing of automotive Windshield wipers - when stationary - with an external frost climate according to claims 1 and 3, characterized,  that simultaneously with the activation of the vehicle drive unit thanks to a special "double plus" circuit technology Excitation "the current switching to the Switching relay / switching transistor, which is the lifting-relevant Controls switching elements, is foiled. 5. Automatic anti-icing of automotive Windshield wipers - when stationary - with an external frost climate according to claims 1 and 3, characterized, that the windshield wiper (s) are activated by specific cam levers, which in multiple arrangement by a Linkage linkage that synchronizes the swivel angle are hinged together, mechanically up and down be levered off, and that the cam lever (s) by (Bending) spring pressure after the windshield wipers are put back in / on the contactless, angled transverse position remain. 6. Automatic anti-icing of automotive Windshield wipers - when stationary - with an external frost climate according to claims 3 and 5, characterized, that the linkage synchronizing linkage at the same time as a limit switch release element for switching off the actuated servomotor unit / servomotor rotation direction to the specifically defined swivel angle sizes serves / is trained. 7. Automatic anti-icing of automotive Windshield wipers - when stationary - with an external frost climate according to claim 5, characterized, that when the windshield wiper (s) are levered up and down Swivel latch simultaneously on the wiper arm (s) is telescoped along the tension spring, which at lifted windscreen wiper (s) the joint recess (s) run over the wiper bracket, which prevents the same due to wind / gravity at an end piece on the contact the respective pane surface and definitely there potentially with anise.