CA2138559A1

CA2138559A1 - Windshield wipers

Info

Publication number: CA2138559A1
Application number: CA002138559A
Authority: CA
Inventors: William Knudsen
Original assignee: William Knudsen; Chrysler Corporation
Current assignee: Old Carco LLC
Priority date: 1993-12-22
Filing date: 1994-12-20
Publication date: 1995-06-23
Also published as: EP0659619B1; US5386098A; DE69424515D1; ATE192981T1; JPH07267050A; DE69424515T2; EP0659619A1

Abstract

An arrangement for heating upper and lower windshield wiper blades parked proximate the lower edge of a windshield utilizes an electric heating grid placed against the inside surface of the windshield, substantially in alignment with the parked wiper blades. The electric heating grid is comprised of a first wire in alignment with the lower blade, an intermediate wire and an upper wire in alignment with the upper blade. The wires have opposite ends which are connected to busses that are disposed at the lower edge of the windshield, the busses having leads for connection to power circuitry. The power circuitry includes a climate control system having a switch which is rotatable to a defrost position. When the switch is rotated to the defrost position so that the climate control system defrosts the windshield, current flows through the grid. As long as the switch is in the defrost position, the current continues to flow. The power circuitry also includes a windshield wiper deicing switch which operates independently of the defrost switch. Associated with the windshield wiper deicing switch is a timer which opens the closed deicing switch after a selected interval of time. This arrangement provides an inexpensive reliable system for deicing windshield wiper blades because the wires are disposed on the windshield against the inside surface of the windshield.

Description

~13~S59 ARRANGEMENT FOR HEATING WINDSHIELD WIPERS
The present invention relates to arrangements for heating w;n~h;eld wipers. More particularly, the present invention relates to arrangements for heating w;n~Rh;eld wipers utilizing electric current.
In freezing weather, w;n~h;eld wiper blades can become frozen to the w;n~h;eld of a motor vehicle when the wiper blades are in their parked position proximate the lower edge of the w;n~h;eld. When one attempts to activate the w;n~h;eld wipers, the torque of the motor applied through a driving linkage for oscillating the wipers may be insufficient to overcome the force with which the wipers are adhered to the w;n~h;eld. The wiper blades may simply not move as the torque is applied which requires that the driver leave the car and manually break the adhesion between the w;n~h;eld wiper blades and windshield. This is, of course, an undesirable aggravation. Further still, the linkage which connects the w;n~h;eld wipers to the motor may fail if the torque of the motor is too high or a fuse may blow, resulting in wipers which are inoperable. Drivers who must use their vehicles immediately or who are impatient may then be tempted to drive without operating w;n~h;eld wipers which is, of course, especially hazardou~ in winter when w;n~h;elds can become covered with ~alt and sand, obscuring the driver's vision. Even if the blades of the win~h;eld wiper are not adhered, there is the difficulty of wiper blades having deposits of ice thereon which at least initially compromises their effectiveness.
Accordingly, there is a need for an arrangement which prevents adhesion of w;n~Rh;eld wiper blades to w;n~h;elds and which prevents the accumulation of ice, frozen snow and frost on wiper blades.
The problem is recognized in the prior art in patents such as U.S. Patent 4,549,471 to Kochy et al.
in which heated air from a defroster system is directed by secondary air ducts to an area of the w;n~h;eld where wi n~; eld wiper blades rest when the wipers are parked. A difficulty with this approach is that it is necessary to warm up the engine and heat the cooling fluid of the engine to a relatively high level before heated air is available for application to the W; n~h; eld. This may take a considerable amount of time, especially on very cold days and tempt the driver to activate the w;n~Rh;eld wipers before the ice or snow adhering the wipers the w;n~h;eld has melted which can result in damage to the wipers or perhaps a blown fuse as described above. Another approach is set forth in U.S. Patent 3,738,252 to Cardinale wherein a hot water radiator is disposed proximate the windshield wiper blade when the w;n~h;eld wiper is in its parked position. Again, it takes time to heat the coolant to a level sufficient to begin melting ice during which time the driver may attempt to activate the w;n~Rh;eld wipers before the ice is melted.
Perhaps in recognition of the deficiencies of arrangements such as those of Kochy et al. and Cardinale, U.S. Patent 5,173,586 to Gold discloses positioning an electric heater on the outside of the w;n~h;eld just below the wiper blade. This is, however, a complex relatively expensive arrangement wherein the heater for the wiper blade must be protected against moisture, wind and general 2138~S9 environmental degradation due to exposure on the outside of the w;n~Rh;eld. The heater is subjected to engine heat as well as moisture, low temperatures and wind-induced pressure differentials, all of which combine to compromise its reliability. The heater is subjected to the greatest environmental stress at a time when it is needed most and is thus more likely to fail at a time it is needed most.
In view of the aforementioned considerations, there is a need for an arrangement to heat w;n~h;eld wiper blades when in their parked mode, wherein the arrangement is relatively inexpensive, reliable and has a relatively rapid response time.
It is an object of the present invention to provide a new and improved arrangement for heating w;n~Qh;eld wiper blades when w;n~h;eld wipers are in a parked mode.
In view of this object and other objects, the present invention is directed to an electric heater for windshield wiper blades wherein the electric heater is positioned in contact with the w;n~h;eld, adjacent the inside surface of the windshield, at a location aligned with the location on the outside of the windshield against which the w;n~Rh;eld wiper rests.
In a more specific embodiment, the electric windshield heater i~ in combination with a control head to engage when an electric back light switch is activated or when a mode switch is activated by, e.g., rotation or depression to a w;n~h;eld defrost setting.
The electric heater times out in a selected time period when the electric back light circuit is activated without with the mode switch in defrost. When the mode switch is in its defrost mode, the electric window heater will remain on as long as the mode switch is at its defrost position.
Various other objects, features and attendant advantages of the present invention will be more fully 21~8559 appreciated as the same becomes better understood when considered in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the several views, and wherein:
Figure 1 is a side elevational view showing a w;n~h;eld with a w;n~h;eld wiper blade in its parked mode on the outside of the w;n~h;eld and a w;n~h;eld wiper heater, configured in accordance with the principles of the instant invention positioned on the inside of the w;n~h;eld in alignment with the wiper blade;
Figure 2 is a back view of the arrangement of Figure 1 showing the configuration of the heating elements comprising the electric heater; and Figure 3 is a circuit diagram showing an arrangement for integrating the electric heater for w;n~h;eld wipers with a defrost system of the automotive vehicle.
Referring now to Figures 1 and 2, there is shown an automotive vehicle 10 which has a w;n~h;eld 12 which isolates the interior environment 14 of the vehicle from the external environment 16. Typically, the w;n~h;eld 12 is fabricated of safety glass having an exterior panel 18 bonded to an interior panel 20 by a layer of adhesive 22. The w;n~Rh;eld 12 has an exterior surface 24 which is exposed to the rigors of the external enviL~ ^nt 16 and an interior ~urface 26 which is generally protected from the external environment since it is exposed primarily to the interior environment 14.
AB is seen in Figure 1, a pair of conventional w;n~h;eld wipers 30 and 32 have rubber or synthetic rubber blades 34 and 36, respectively, which wipe the outer surface 24 of the w;n~h;eld 10. In Figure 1, the w;n~h;eld wipers 30 and 32 are shown in their parked mode at the bottom of the w;n~fih;eld.

Upon activation of a conventional w;n~Rh;eld wiper motor (not shown), the wipers 30 and 32 oscillate to clean the outer surface of the window 24 but when the automotive vehicle i8 not being used, the w;nr~Rh;eld wipers 30 and 32 are in the position of Figure 1. In cold, wet climates, snow and ice tend to accumulate around the w;n~lRh;eld wipers and can adhere the w;n~lRh;eld wiper blades 34 and 36 to the outer surface 24 of the w;n-lRh;eld. This may occur due to a snow and ice storm or perhaps may occur when water kept liquid by the operation of a defrosting system or the vehicles engine freezes when the vehicle i8 not being used.
In accordance with the features of the present invention, an electric grid 40 is disposed in alignment with the parking area 38 on the outer surface 24 of the w;n~lRh;eld 10 80 as to locally heat the parking area. In the preferred embodiment, the electric heating grid 40 is comprised of three wires 42, 44 and 46, each of which is in abutment with the back surface 26 of the w;n-lRh;eld 10. The wire 42 is aligned with the wiper blade 34 of the lower w;n~Rh;eld wiper 30 while the wire 46 is aligned with the wiper blade 36 of the upper windshield wiper 32. The wire 44 is disposed midway between the wires 42 and 46 80 that the entire heating area 48 on the inside surface 26 of the w;n~lRh;eld 10, disposed proximate the parking area 38 on the outside surface 24 of the w;n~Rh;eld, is heated when the grid 40 is energized.
As is seen in Figure 2, the grid 40 is localized at the center of the w;n~h;eld 12 with the heating wires 42, 44 and 46 converging at ends 52 and 54 to busses 56 and 58, respectively. The busses 56 and 58 have leads 60 and 62, respectively, which are connected to electrical power sources, as seen in Figure 3. The busses 56 and 58 each extend proximate the lower edge 64 well out of the view of the driver and allow heat to be concentrated where it is most ~13~59 needed, generally in the area 48 where the w;n~h;eld wipers 30 and 32 are parked.
Referring now to Figure 3 where a circuit diagram for a control circuit 70 is shown, it is seen that the lead 60 connects the grid 40 to climate control circuitry 40 and line 76 connects the lead 62 to a fuse. The climate control circuit includes a rotary switch 80 which rotates between a number of positions including an off position 82 and a defrost position 84. When the rotary switch 80 is in the defrost position, operating the defrost system of the automobile, the heating grid 40 is energized and current flows through the lines 42, 44 and 46, heating the area 48 in the w;n~h;eld. As long as the climate control system 74 is in the defrost mode, the grid will remain energized to deice wiper blades 34 and 36 (see Figure 1). When the switch 80 is not rotated from the off to the defrost position, the grid 40 comprising the electric wiper deicer may still be operated by switch 86. The switch 86 includes a conventional timer 88 connected thereto which times out after 10 minutes, opening the switch 86 and interrupting current to the heating grid 40. Thus, the heating grid 40 may be activated by either the climate control system 74 of the automotive vehicle or by a separate isolated switch 86.
Without further elaboration, it is believed that one skilled in the art can, using the preceding description, utilize the present invention to its fullest extent. The following preferred specific embodiment~ are, therefore, to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way whatsoever.
In the foregoing and in the following examples, all temperatures are set forth uncorrected in degrees Celsius and unless otherwise indicated, all parts and percentages are by weight.

213~59 E X A M P L E
The following table is an example of a preferred grid system for a vehicular w;n~h;eld which has worked effectively with the thickness of the wires being approximately 0.0005 inches.

STUDY OF EWD (VERSION 3c) THREE pARAT.T.FT. GRID LINES
BUSS LEFT TOP MIDDLE BOTTOM BUSS RIGHT
_________________________________________________________ LENGTH mm394 1029.7 954.7 888 394 WIDTH mm7 0.8 0.6 0.6 7 _________________________________________________________ Reach ohm 0.263844 6.0335277.458752 6.906397 0.263844 Rsegment ohm 0.263844 2.249190 0.263844 Rewd ohm 2.776879 Vewd volts 13 lewd amp 4.681513 leach amp 4.681513 1.7451831.411712 1.524617 4.681513 Peach watt 5.782574 18.3761014.86478 16.05363 5.782574 Pneeded (P/A = C~
O.5 watt/in) 73% -10% -26% -8% 73% 1 0 P/A 0.73 0.45 0.40 0.46 0.37 CC~
In the above table, denotion "ewd" means "electric window defro~t"
and the other denotions being self-explanatory.

g The preceding examples can be repeated with similar success by substituting the generically or specifically described reactants and/or operating conditions of this invention for those used in the preceding examples.
From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention, and without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions.

Claims

1. In combination, a windshield for an automotive vehicle having an outside surface exposed to the environment and an inside surface shielded from the environment, wherein the outside surface has a parking area thereon on which a pair of windshield wiper blades rest when in a parked mode, a windshield wiper heater comprising a grid disposed in contact with the inside surface at an area substantially aligned with the parking area of the outside surface, and a power circuit for supplying electric current connected to the grid, whereby upon applying electric current through the electric grid, the parking area of the windshield is heated for the purpose of melting ice or snow accumulated around the windshield wiper blades.

2. The combination of claim 1, wherein the grid is comprised of three wires, the first of which is aligned with a lower windshield wiper blade, the second of which is disposed between the lower and upper windshield wiper blade and the third of which is aligned with the upper windshield wiper blade.

3. The combination of claim 1, wherein the parking area on the front surface of the windshield is spaced by selected distances from the side edges of the windshield and wherein the grid is disposed only in an area substantially aligned with the parking area, the grid having first and second ends which are joined to first and second busses which extend from the grid to locations proximate the side edges of the windshield, the busses having leads thereon for connection to the power circuit.

4. The combination of claim 3, wherein the power circuit for the electric heating grid includes a climate control system for the interior of the automotive vehicle, the climate control system having a defrost setting for heating the entire windshield, the climate control system having a mode control switch connected to the electric heating grids wherein when the switch is in a defrost setting, the electric heating grids are energized.

5. The combination of claim 4, further including a separating deicing switch disposed and parallel with the defrost switch for connecting the electric heating grid to the power source independent of the defrost switch, the separate deicing switch having a timer associated therewith for opening the separate deicing switch after a selected period of time so as to interrupt power to the electric heating grid.

6. The combination of claim 5, wherein the lines of the electric heating grid are wires having a diameter of about 0.0005 inches.