DEVICE FOR REMOVING ICE AND/OR SNOW FROM WINDOWSCREEN WIPERS

Abstract: A device (1) for removing ice and/or snow from windshield wipers, particularly for use on relatively heavy vehicles, of the type designed to lift the windshield wiper arm (20) such that the wiper blade (22) is brought out of contact with the vehicle window (23), and which thereafter causes the windshield wiper arm (20) to return to its original position so that the wiper blade (22) knocks against the window (23) and ice and/or snow is/are thereby caused to loosen from the wiper blade (22). The device (1) comprises a pneumatic cylinder (2) and a movable piston (5) within the cylinder. The cylinder (2) is divided into a high pressure chamber (9) and a low pressure chamber (10). The high pressure chamber (9) may optionally be placed under a higher pressure than the low pressure chamber (10), by means of a compressed air or a vacuum, in order to move the piston (5) in a first direction, causing the wiper arm (20) to lift away from the window (23). In the low pressure chamber (10) there is provided a return spring (12) which is designed to return the piston (5) in a second, opposite direction to allow the wiper arm (20) to move toward the window (23) when the pressure difference between the high pressure chamber (9) and the low pressure chamber (10) is annulled. The device (1) is adapted to be positioned such that it is operative between the vehicle body (21) or window (23) and the wiper arm (20).

Description: DEVICE FOR REMOVING ICE AND/OR SNOW FROM INDO SCREEN WIPERS The present invention relates to a device for removing ice and/or snow from windshield wipers, particularly for use on relatively heavy vehicles, in accordance with the preamble of claim 1. A number of devices of this type are known. Among these are the one described in US 2,784,438. Here, there is shown a device which raises the windshield wiper up from the window, in order thereafter to release the wiper so that snow and/or ice is knocked off the wiper blade. The lifting ofthe windshield wiper arm is brought about by means of a solenoid mounted on the arm and operative between a fastening means for the solenoid and a bracket on the wiper arm. As is known, the solenoid is electrically powered. This implies that it must be well sealed in order to prevent moisture and/or dust from penetrating into the mechanism and impairing its function as, for example, in the case of a short circuit. Further, a special bracket must be designed for the windshield wiper arm; this necessitates the replacement ofthe windshield wiper arm in cases where the solenoid is to be mounted after delivery on a vehicle which has not been equipped with such a device from the factory . . For this reason the device also becomes very expensive for post-delivery installation. US 4,309,789 also shows an apparatus that utilizes compressed air to remove ice and/or snow from the windshield wiper blade. Here, compressed air is supplied to an internal duct running along the length ofthe windshield wiper blade, which causes the windshield wiper blade to inflate, almost like a balloon, and the snow and/or ice will thereby be loosened. In this case, however, there will be need for a very special windshield wiper blade, which would be expensive to replace. The wiper blade will also be quite vulnerable to damage, since merely a single crack extending from the surface ofthe blade into the duct will puncture the duct and impair the snow and ice removing function. Considering how frequently it is necessary to change a common windshield wiper blade, this device would have to be very uneconomical for use over a long period of time. With the present invention, we seek to provide a device that is simple to mount after the vehicle has left the factory, is not dependent on electric or electronic components disposed on the outside ofthe vehicle, and is reasonable to procure and reliable to operate. This is achieved by the features disclosed in the characterizing clause ofthe following claim 1. Further embodiments are disclosed in the subsequent dependent claims. The invention will now be described in more detail with reference to the accompanying drawings, where Figure 1 is a side view ofthe device, from a first direction, Figure 2 is a side view ofthe device, from a direction perpendicular to the first direction, Figure 3 is a top view of the device, Figure 4 is a cross-sectional view ofthe device, and Figure 5 is a view ofthe device moimted in conjunction with a windshield wiper arm. The device 1 is shown in Figures 1 and 5 mounted in connection with a windshield wiper arm 20, which is illustrated in cross section in Figure 1. The device consists of a housing 2 and a foot 3. Projecting from an opening 4 at the top of housing 2 is a piston 5 (see Figure 4). Fastened to the top of piston 5 by means of a screw 6 is a lifting hook 7. The lifting hook 7 is provided at its outermost end with a lifting member 8. Inside housing 2 on one ofthe sides of piston 5 is formed a high pressure chamber 9, and on the other side of piston 5 is formed a low pressure chamber 10. High pressure chamber 9 is supplied with compressed air via a compressed air duct 11. In low pressure chamber 10 is positioned a return spring 12, which urges piston 5 into housing 2 when the compressed air in high pressure chamber 9 is released. An O-ring seal 13 ensures that dust and moisture do not penetrate into housing 2. As illustrated in Figure 5, the device 1 may be placed with foot 3 against the body 21 of a vehicle. Device 1 is arranged such that lifting member 8 is situated underneath a section of windshield wiper arm 20. Alternatively, the entire device, if space permits, may be placed between the vehicle body 21 and the windshield wiper arm 20. Then the screw 6, or optionally a suitable striking member mounted thereon, will form the thrust surface against the wiper arm 20. The compressed air duct 11 may be connected in a practical manner via a suitable valve (not shown) to a compressed air system already existing in the vehicle. The valve may be, for example, electrically powered and may be situated inside the driver's cabin. When lumps of ice or clumps of snow begin to form on the windshield wiper blade 22, the vehicle driver may operate a switch, preferably several times in succession, and thereby send a plurality of compressed air pulses to the high pressure chamber 9. The piston will thereby be thrust out ofthe housing with great force, and will thus lift the wiper arm 20, thereby bringing wiper blade 22 out of contact with the window pane 23. The return spring 12 will ensure that the piston 5 is returned to its original position in housing 2 when the presssure in high pressure chamber 9 has dropped sufficiently. A plurality of successive operations ofthe valve will cause piston 5 to be lifted and returned to its original position several times in succession, and ice and snow will thereby be knocked off the windshield wiper blade 22 in a very effective manner, as the blade repeatedly strikes against the window pane 23. In vehicles without an internal compressed air system, a small compressor must be mounted after delivery for the operation ofthe ice/snow removal device. Optionally the device may also be designed for attachment to a vacuum, e.g., the vehicle's vacuum brake booster. In that case, the vacuum will have effect on the low pressure chamber 10, while the high pressure chamber 10 remains below atmospheric pressure. Piston 5 may also be designed with adjustable length to adapt to various spacing relationships between the vehicle body and the wiper arm. The device may also be adhered securely to the vehicle window pane and thereby be operative between the window pane and the wiper arm, or it may be integrated into the vehicle body with factory installation. The device components could basically be made of plastic, e.g., POM.

Claims: P a t e n t C l a i m s 1. A device (1) for removing ice and/or snow from windshield wipers, particularly for use on relatively heavy vehicles, ofthe type designed to lift the windshield wiper arm (20) such that the wiper blade (22) is brought out of contact with the vehicle window (23) and which thereafter causes the windshield wiper arm (20) to return to its original position so that the wiper blade (22) knocks against the window (23) and ice and/or snow is/are thereby caused to loosen from the wiper blade (22), characterized in that the device (1) comprises a pneumatic cylinder (2) and a movable piston (5) within the cylinder (2), which cylinder (2) is divided into a high pressure chamber (9) defined by the side walls ofthe cylinder (2), by one end wall of the cylinder (2) and by the end face ofthe piston (5), and a low pressure chamber (10) defined by the side walls ofthe cylinder (2), by the other end wall ofthe cylinder (2), by the annular face ofthe piston (5) and by the piston rod, which high pressure chamber (9) may optionally be placed under a higher pressure than the low pressure chamber (10) in order to move the piston (5) in a first direction, causing the wiper arm (20) to lift away from the window (23), and in which low pressure chamber (10) there is provided a return spring (12) designed to return the piston (5) in a second, opposite direction to allow the wiper arm (20) to move toward the window (23) when the pressure difference between the high pressure chamber (9) and the low pressure chamber (10) is annulled, and that the device (1) is adapted to be positioned so that it is operative between the vehicle body (21) or window (23) and the wiper arm (20). 2. A device according to claim 1, characterized in that the high pressure chamber (9) may be pressurized by connecting the chamber (9) to a compressed air system in the vehicle via a valve operated by the driver. 3. A device according to claim 1, characterized in that, in the low pressure chamber (10), a vacuum may be created by connecting the chamber (10) to a vacuum source in the vehicle via a valve operated by the driver. 4. A device according to claims 1,2 or 3, characterized in that a lifting hook (7) is connected to the top ofthe piston (5), which lifting hook (7) is adapted to grasp beneath the wiper arm (20), and that the axial distance between the bottom ofthe device (1) and the contact surface ofthe lifting hook (7) against the wiper arm (20) is less than the height ofthe device (1). 5. A device according to any one ofthe preceding claims, characterized in that the operative area for the device is adjustable, due to the fact that, e.g., the height ofthe piston (5) and/or the lifting hook (7) is adjustable.

Inventors: LOFTHEIM THOR ANDERS, LOFTHEIM, THOR, ANDERS
Applicants: LOFTHEIM THOR ANDERS, LOFTHEIM, THOR, ANDERS
Application year: 1996
Main classification: B60S1
IPC codes: B60S1