Abstract:
A windshield wiper includes a plurality of electrical resistance heater elements. Some of the heater elements are located in the flexible wiper blade body and some of the heater elements are located in a wiper blade back element. The heater elements are spaced apart from each other so heat can be evenly distributed over the entire wiper blade and significant amounts of heat can be generated.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to the general art of electric heating, and to the particular field of electrically heated vehicle components. 
     2. Discussion of the Related Art 
     Ice-covered windshields are a constant problem in many areas of the country during much of the winter. Many people must add time to a commute in order to clear their windshield. Since clearing the windshield is an important safety concern, it is imperative that such an operation be as thorough as possible. This often requires a person to scrape ice from the windshield. This can be a difficult operation, especially if it is very cold. 
     Therefore, there is a need for a device for clearing a windshield in an efficient manner. 
     The art contains many examples of devices intended to clear ice from a windshield. These devices include heating the windshield itself as well as heated windshield wipers. However, all of the known devices have a drawback in that the wiper itself is not adequately heated. Generally, only the flexible portion of the wiper blade that contacts the windshield is heated. This works fairly well; however, even with a heated flexible portion, the wiper may not be totally effective because the amount of heat necessary to either free the wiper or to adequately clear the windshield is not available from the single source of heat. 
     While it might appear that simply increasing the amount of heat generated by a windshield wiper is a solution to the above-discussed problem, such is not the case since a great deal of heat may damage the flexible wiper blade. Therefore, there is a limit to the amount of heat that can be safely and efficiently generated from known heated windshield wipers. 
     Therefore, there is a need for a device for clearing a windshield in an efficient manner, yet does not endanger the flexible wiper blade portion of the windshield wiper. 
     In some conditions, it is cold enough where ice continues to form on the windshield and on the wiper even after the vehicle is warmed up and the windshield has been initially cleared. Under such conditions, the windshield wiper must continually clear the windshield. The wiper must thus generate sufficient heat to prevent ice from building up on the wiper during operation. 
     Therefore, there is a need for a device for clearing a windshield in an efficient manner and that can generate heat in a manner that prevents ice from building up on the windshield wiper during operation of the windshield wiper. 
     Since some climate conditions are so severe, it may be necessary to generate heat from a variety of directions and sources for the same windshield wiper. This requirement may result from severe cold or from a driving ice storm in which ice can accumulate on the wiper during driving and thus reduce its effectiveness. Many known heated windshield wipers have only a single source of heat and thus may not be fully effective during all conditions. 
     Therefore, there is a need for a device for clearing a windshield in an efficient manner that can be effective under nearly any climate condition. 
     Some known heated windshield wipers are very difficult and expensive to replace due to the circuitry associated with the wiper. In fact, some wipers must be entirely replaced, including the entire wiper blade structure, including the carrier bows, due to this problem. This can be expensive and, in some instances, require the services of a skilled mechanic thereby further increasing the costs. The cost problem has inhibited the commercial acceptance of heated windshield wipers. Since a heated windshield wiper can be such a safety factor, it is important to encourage the use of such equipment. 
     Therefore, there is a need for a device for clearing a windshield in an efficient manner and which can be easily installed and changed. 
     Still further, since windshield wipers often must function and operate under severe weather conditions, some known heated windshield wipers may be subject to failure. Ice can become lodged in some electrical connections thereby vitiating, if not totally eliminating, the heating function of the wiper blade. 
     Therefore, there is a need for a device for clearing a windshield in an efficient manner and that can continue to function and operate even if a portion of the device fails or become impaired. 
     PRINCIPAL OBJECTS OF THE INVENTION 
     It is a main object of the present invention to provide a device for clearing a windshield in an efficient manner. 
     It is another object of the present invention to provide a device for clearing a windshield in an efficient manner, yet does not endanger the flexible wiper blade portion of the windshield wiper. 
     It is another object of the present invention to provide a device for clearing a windshield in an efficient manner and that can generate heat in a manner that prevents ice from building up on the windshield wiper during operation of the windshield wiper. 
     It is another object of the present invention to provide a device for clearing a windshield in an efficient manner that can be effective under nearly any climate condition. 
     It is another object of the present invention to provide a device for clearing a windshield in an efficient manner and which can be easily installed and changed. 
     It is another object of the present invention to provide a device for clearing a windshield in an efficient manner and that can accommodate ice newly hitting a windshield as a vehicle is being operated as well as ice sticking on the windshield. 
     It is another object of the present invention to provide a device for clearing a windshield in an efficient manner and that can continue to function and operate even if a portion of the device fails or become impaired. 
     SUMMARY OF THE INVENTION 
     These, and other, objects are achieved by a heated windshield wiper blade unit comprising a wiper blade back element having a first electrical resistance heater system embedded therein, a one-piece flexible windshield wiper element having a second electrical resistance heater system embedded therein and spaced from the first electrical resistance heater element, electrical connections on the first and second electrical resistance heater systems, and an electrical circuit electrically connected to the electrical connections and connecting the electrical reistance heater elements together in parallel with each other. 
     The dual heating elements permit the windshield wiper of the present invention to generate sufficient heat to clear a windshield of ice under nearly any condition. Still further, the dual source of heat permits the windshield wiper of the present invention to keep itself clear of ice during nearly any condition. The windshield wiper of the present invention has simple male and female jacks to connect the wiper heating elements to a control circuit so the wiper is easily installed and changed when necessary. Furthermore, because there is a dual heat source in the windshield wiper of the present invention, the heat source in the flexible wiper portion of the windshield wiper is not required to generate as much heat as would be the case if that heat source were the only source of heat for the windshield wiper. Thus, if a great deal of heat is required, the flexible wiper portion of the windshield wiper will not be subject to a great deal of heat from the inside of that wiper blade portion. Thus, even though a great deal of heat can be generated from the windshield wiper of the present invention, there is little or no danger of damaging the flexible portion of the windshield wiper due to placing too much heat directly on that portion of the wiper. 
     Still further, since there are a plurality of different heat sources in the windshield wiper of the present invention, the wiper can accommodate ice from a plurality of directions. That is, ice hitting the windshield can be accommodated by the windshield wiper of the present invention while the windshield wiper can also accommodate ice generated on the windshield. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view a heated windshield wiper blade unit embodying the teaching of the present invention. 
     FIG. 2 is a side elevational view of the heated windshield wiper blade unit of the present invention. 
     FIG. 3 is an enlarged cross-sectional view taken along line  3 — 3  of FIG.  1 . 
     FIG. 4 is a perspective view of a switch used in an electrical circuit associated with the heated windshield wiper of the present invention. 
     FIG. 5 is a schematic, illustrating an electrical circuit associated with the heated windshield wiper of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Other objects, features and advantages of the invention will become apparent from a consideration of the following detailed description and the accompanying drawings. 
     Shown in FIG. 2 is a windshield wiper system  10  which can be used on most land vehicles, such as automobiles, trucks and the like. Windshield wiper system  10  includes a wiper arm  12  which is mounted at one end thereof on the vehicle and has a main pivot mount  14  on the other end thereof which is pivotally connected to a main wiper blade support structure  16  and which pivotally connects wiper arm  12  to main wiper blade support structure  16 . Two carrier bows  18  and  20  are pivotally attached to main wiper blade support structure  16  and each includes a pivot mount, such as pivot mount  22 . Wiper arm  12  and the structure so far described functions and operates in a manner usual to windshield wiper blade systems and thus will not be further discussed. 
     Attached to wiper blade arm  12  is a heated windshield wiper blade unit  30  embodying the present invention. Wiper blade unit  30  not only heats a windshield being cleaned, but maintains a heated environment so ice and snow can be melted off the wiper blade unit  30  itself thereby increasing the efficiency of the overall windshield cleaning operation. 
     As shown in FIGS. 1-3, heated windshield wiper blade unit  30  comprises a wiper blade back element  40  having a body  42 , which can be constructed of metal or like heat conducting material, a first end  44  and a second end  46  on body  42 , a first side  48  and a second side  50  on body  42  and a longitudinal axis  52  extending between first and second ends  44  and  46  of body  42 . A slot  54  is defined through body  42  and extends along longitudinal axis  52  of body  42  from adjacent to first end  44  to adjacent to second end  46  of body  42 . Slot  54  has a first side edge  56  located adjacent to first side  48  of the body  42  and a second side edge  58  located adjacent to second side  50  of body  42 . 
     A first electrical resistance heater element  60  is embedded in body  42  and extends in the direction of longitudinal axis  52  of the body from first end  44  of body  42  to second end  46  of body  42  and is located adjacent to slot  54  and between first side edge  56  of the slot  54  and first side  48  of body  42 . A second electrical resistance heater element  62  is embedded in body  42  and extends in the direction of longitudinal axis  54  of body  42  from first end  44  of the body  42  to second end  46  of body  42  and is located adjacent to slot  54  between second side edge  58  of slot  54  and second side  50  of body  42 . The electrical resistance heaters  60  and  62  are of the type known in the art and thus will not be further discussed. 
     As indicated in FIG. 5, an electrical connection  66  between the first electrical resistance heater element  60  and the second electrical resistance heater element  62  electrically connects those two electrical resistance heater elements  60  and  62  in parallel with each other. As shown in FIG. 1, a female electrical connector element  68  is located in first end  44  of body  42 , and as shown in FIG. 5, an electrical connection  70  between female electrical connector element  68  and electrical connection  66  between first electrical resistance element  60  and second electrical resistance element  62  electrically connects those elements  60  and  62  together. Body  42  of wiper blade back element  40  further includes an inside surface  72  and an outside surface  74 . 
     Windshield wiper blade unit  30  further includes a windshield wiper member  80  which includes a one-piece flexible body  82  which can be formed of rubber or plastics-type material as will be understood by those skilled in the art based on the teaching of the present disclosure. Body  82  has first side  84  having a distal end  86  and a proximal end  88  located near body  42 , a second side  90  having a distal end  92  and a proximal end  94  located near body  42 . An apex  96  connects distal end  86  of first side  84  to distal end  96  of second side  90  of flexible body  82 . A base  98  connects proximal end  88  of first side  84  to proximal end  94  of second side  90  of flexible body  82 . Body  82  further includes a neck element  100  having a proximal end  102  on base  98  of flexible body  82  and a distal end  104  spaced from base  98 . Neck element  100  extends through slot  54  defined through body  42  of wiper blade back element  40  with proximal end  102  of neck element  100  being located adjacent to inside surface  72  of back element  40  and distal end  104  of neck element  100  being located adjacent to outside surface  74  of wiper blade back element  40 . 
     Body  82  further includes an abutment element  110  on distal end  104  of neck element  100  of windshield wiper member  82  and which is located adjacent to outside surface  74  of body  42  of wiper blade back element  40  and includes a first end  112 , a second end  114 , and a longitudinal axis  116  extending between first end  112  of abutment element  110  and second end  114  of abutment element  110  in the direction of longitudinal axis  52  of windshield wiper blade unit  30 . Flexible body  82  further includes a first end  120  located adjacent to first end  44  of wiper blade back element  40  and a second end  122  located adjacent to second end  46  of wiper blade back element  40 . Abutment element  110  further has a longitudinal axis  124  which extends between first end  120  of flexible body  82  and second end  122  of flexible body  82 . 
     Windshield wiper blade  30  further includes a third electrical resistance heater element  130  embedded in windshield wiper body  82  and which extends in the direction of longitudinal axis  124  of flexible windshield wiper body  82  from first end  120  of the windshield wiper body to second end  124  of the windshield wiper body. A female jack element  132  is positioned in first end  120  of the windshield wiper body. Windshield wiper blade  30  further includes a fourth electrical resistance heater element  134  embedded in abutment element  110  of windshield wiper body  82  and extends in the direction of the longitudinal axis of the abutment element from first end  112  of the abutment element to second end  114  of abutment element  110  of windshield wiper body  82 . 
     As shown in FIG. 5, an electrical connection  136  between the third electrical resistance heater element  130  and the fourth electrical resistance heater element  134  electrically connects those electrical resistance heaters  130  and  134  in parallel with each other. An electrical connection  138  between female jack element  132  and electrical connection  136  between third electrical resistance heater element  130  and fourth electrical resistance heater element  134  electrically connects those heater elements  130  and  134  in parallel with first electrical resistance heater element  60  and second electrical resistance heater element  62 . 
     As can be understood from the foregoing, the four electrical resistance heaters of windshield wiper blade unit  30  place heat in the necessary locations on the unit  30  and can continue to operate even if one or more of the heaters fail. Since the heat sources are spaced from each other, no individual section of the unit is subject to an unduly high heat source and yet the overall unit is capable of generating a significant amount of heat. 
     Body  42  of wiper blade back element  40  is interposed between abutment element  110  of windshield wiper body  82  and base  98  of windshield wiper body  82  to be securely held there so the windshield wiper body is securely held on the back element. 
     As shown in FIG. 5, device  30  further includes an electrical circuit  150  which includes a power source  152 , an electrical switch  154 , an electrical connector  156  electrically connecting the switch  154  to the power source  152 , a first male electrical connector element  158  which connects the switch  154  to female jack connector  132 , a second male electrical connector element  160  which connects switch  154  to female jack connector  68 , a first electrical connector  164  electrically connecting the switch  154  to first male jack  158  and a second electrical connector  166  electrically connecting switch  154  to second male jack  160 . 
     Switch  154  can be located inside the vehicle on the dashboard or the like, and power source  152  can be the vehicle battery if desired. 
     It is understood that while certain forms of the present invention have been illustrated and described herein, it is not to be limited to the specific forms or arrangements of parts described and shown.