HK1001097B

HK1001097B - Safety edge switch for detection of obstructions encountered by a moving object

Info

Publication number: HK1001097B
Application number: HK98100019.0A
Authority: HK
Inventors: A. Kramer Dennis; E. Peck David; A. Brookman Marc
Original assignee: Rockwell International Corporation
Priority date: 1992-09-25
Filing date: 1993-09-23
Publication date: 1998-05-22

Description

This invention relates to a safety edge switch for power actuated devices such as automotive vehicle windows and, more specifically, to a safety edge switch manufactured as a single pass co-extrusion.

The conventional safety edge switch typically includes a carbon-filled elastomeric material which defines the outer peripheral portion thereof as taught by Beckhausen in US-A-5 023 418. The preamble of the independent claim 1 is known from this document. It has been determined that conductive elastomeric materials which feature a carbon filter are sensitive to environmental exposure and degrade rapidly losing their resiliency and electrically conductive properties. Conductive elastomeric materials may be replaced by nonconductive elastomeric material having conductive strips attached thereto as taught by Hüllwegen in DE-U-86 08 064. However, such construction necessitates non-integral members and additional parts, see separate Aluminium hollow section supporting a second conductive strip. Therefore, there is a need for a seal which can provide an outer peripheral barrier that functions to define an environmental shield about the conductive portions as well as functions as a component of the safety seal assembly, thereby minimizing parts and extending the useful life thereof.

This object is realised by the features of claim 1.

The present invention includes a safety edge switch which may be utilized to sense an obstruction present in a window opening upon closure of the respective window of an automotive vehicle. The switch may be secured to a window opening by adhesive attachment. The switch includes an outer peripheral portion preferably shaped as an oval and constructed of a resilient material which defines a central first aperture. A second smaller structure constructed of conductive elastomer is located in the central aperture and secured to an internal wall thereof. A portion of the outer peripheral member opposite the second smaller oval shaped structure features a conductive elastomeric portion extending parallel thereto and maintained separate therefrom by the resilient physical properties of the outer peripheral portion. The assembly provides a switch which may be actuated upon displacement of a first dimension A which preferably interrupts application of power to the actuator causing window closure and, in addition, permits a second displacement which accommodates any overtravel such as dimension B which may occur subsequent to removal of power from the actuator closing the referenced window. The conductive elastomeric portions include copper drain wires for reliable low resistance switching along the length thereof, such that the obstruction causing displacement of the safety edge switch at any location therealong provides a change in continuity of electrical conduction therethrough. The device as indicated is sensitive to normal forces in addition to any angular force which may be applied thereto. The switch is co-extruded as one assembly.

These and other aspects of the present invention will become more readily apparent by reference to the following detailed description of the embodiments as shown in the drawings.

Figure 1 is a safety edge switch system of the present invention;
Figure 2 is a cross section of the safety edge switch of the present invention; and
Figure 3 is a cross section of the safety edge switch of the present invention.

The preferred embodiment, as shown in cross section in Figure 2 is a safety edge switch 10 installed along seal 12 of an automotive vehicle window opening. A U-shaped metal insert 14 is utilized to secure seal 12 to frame 17 of a window opening. Safety edge switch 10 comprises a continuous co-extrusion featuring an outer peripheral portion defining an integral first member 22 shown having a generally oval section with indentations 24, 24 located on laterally opposing sides thereof. The internal aperture defined by the first member 22 includes a second smaller oval shaped structure defining a second member 26 preferably constructed of a carbon-filled elastomeric material and secured to the internal wall of outer peripheral portion 22. Means 28 in the form of a strip placed on the opposing internal wall of first member 22 is also constructed of carbon-filled elastomeric material. Second member 26 and means 28 include a copper drain wire 30,31 which provide reliable low resistance switching along the length of switch 10. Safety edge switch 10 is secured to seal 12 by adhesive 32. Other techniques include mechanical attachment means or, in fact, co-extrusion of the safety edge switch 10 with seal 12. A normal force applied in the direction of arrow 34 will initially cause compression of the first member 22, along indentations 24. Displacement of dimension A will bring second member 26 and means 28 into contact with one another providing indicia of displacement A by a change in the electrical continuity through drain wires 30,31. In operation, such a displacement will provide indicia of the presence of an obstruction present in the window opening during closure of window 18 against seal 10. Upon detection of the presence of such an obstruction, power to motor 100, shown in Figure 1, causing window closure will be interrupted. Inertia associated with motor 100, and window 18 will result in a certain amount of overtravel from the point at which power is interrupted. It is anticipated that the amount of overtravel will be accommodated by displacement indicated by dimension B which is caused to occur by deflection of second member 26. As such, travel of dimension B subsequent to interruption of power to motor 100 will absorb any further motion of window 18. Those skilled in the art will note that the physical structure of the switch 10 is such that the first member 22 will initially compress and second smaller oval shaped second member 26 will compress only when travel of dimension A has occurred. Those skilled in the art will recognize that continuity of the drain wire circuit may be provided by connecting drain wires 30,31 through resistor 200 which provides a known impedance at the end of switch 10 opposite the end which is connected to motor controller 202. Alternatively, the connection of drain wires 30, 31 may be accomplished by use of a connector as described in WO-A-9408119.

The preferred embodiment is also sensitive to forces imposed in directions other than normal such as an angular force occurring in the direction of arrow 35. The construction of the first member 22 provides sufficient dimensional distortion upon the incidence of angular forces to cause the second member 26 and the means 28 to come into contact with one another to provide indicia of the presence of an obstruction in the window opening upon closure which causes displacement of magnitude equal or proximate to dimension A. The present invention may be prepared using an extrusion die essentially featuring cross-sectional dimensions of the structure shown in Figure 2 and utilizing a carbon-filled Santoprene for second member 26 and means 28, and a non-carbon-filled Santoprene for first member 22. Santoprene is a trademark of Monsanto Corporation. The extrusion may include the copper drain wires 30,31.

Figure 3 illustrates an alternative embodiment of the present invention in which the outer peripheral portion 22 includes means 28 in the form of a wall section formed entirely of conductive elastomeric material. A second smaller oval shaped member 26 is formed as an integral portion of the first member 22. Drain wires 30,31 are copper wires which provide reliable low resistance switching along the entire length of the safety edge circuit. A normal force applied in the direction of arrow 34 will deform first member 22 at indentations 24. Displacement of dimension A will cause contact between second member 26 and means 28 providing indicia of the presence of an obstruction present in the opening sought to be monitored. Detection of such displacement will result in interruption of power to the actuator causing window closure. System inertia will result in overtravel from the point at which power was interrupted. It is anticipated that the amount of overtravel will be accommodated by further displacement indicated by dimension B.

Claims

Safety edge switch (10) for detection of obstructions in a vehicle window opening, comprising:
an integral first member (22) including a continuous circuit of sides having an internal and external wall defining a first aperture;

said first member(22) being constructed of a resilient material, a portion of said first member (22) including means (28) providing electrical conductivity therethrough;

a second member (26) affixed to said internal wall of said first aperture opposite said portion of said first member (22) including means (28) to provide electrical conductivity through said first member (22),

said second member (26) being constructed of a conductive resilient material; and

first and second opposed ends of said switch (10) including means for conductive connection to said portion of said first member including means (28) to provide electrical conductivity through said first member (22) and to said second member (26),
characterized in that:
said portion of said first member (22) including means (28) providing electrical conductivity therethrough is provided on the internal wall of the first member (22) or is an integral portion of said first member (22);

said second member (26) being a continuous circuit of sides defining a second aperture;

said first aperture and said second aperture are sized in relation to provide a first signal in response to a first predetermined displacement (A) of said second member (26) into contact with said portion of said first member (22) including means (28) providing electrical conductivity through said first member (22), and to permit a second predetermined displacement (B) of said second member (26) thereafter.
The safety edge switch according to claim 1 wherein said second end includes means (30,31) for determining continuity through said second member (26) and through said means (28) for providing electrical conductivity through said first member (22) and wherein said first end includes means (200) for providing a predetermined impedance value between said second member (26) and said means (28) for providing electrical conductivity through said first member (22).
The safety edge switch according to claim 1 or 2 wherein said integral first member (22) including a continuous circuit of sides having an internal wall includes laterally displaced indentations (24) formed therein.
The safety edge switch according to any of the claims 1 to 3 wherein said switch (10) is affixed to a seal (12), said seal (12) defining a closure surface for a vehicle window (18).
The safety edge switch according to claim 4 wherein said seal (12) is affixed in a U-shaped frame (14) and secured to a top portion of a window frame (17).
The safety edge switch according to any of the claims 1 to 5 wherein said means (28) for providing electrical conductivity through said first member (22) includes a wire (30) surrounded by carbon dispersed in the resilient material from which said first member (22) is constructed.
The safety edge switch according to any of the claims 1 to 6 wherein said second member (26) includes a wire (31) surrounded by carbon dispersed in the resilient material from which said second member (26) is constructed.
The safety edge switch according to any of the claims 1 to 7 wherein a portion of said continuous circuit of sides of said secondmember (26) comprises said first member (22).
The safety edge switch according to any of the claims 1 to 8 wherein said means (28) for providing electrical conductivity through said first member (22) comprises a continuous conductive surface disposed on said internal wall of said first member (22) opposite said second member (26).