WO1999006661A1

WO1999006661A1 - Safety edge for an electrically operated door

Info

Publication number: WO1999006661A1
Application number: PCT/CA1998/000725
Authority: WO
Inventors: Andrew Joseph Gardner
Original assignee: Andrew Joseph Gardner
Priority date: 1997-07-29
Filing date: 1998-07-28
Publication date: 1999-02-11
Also published as: AU8619898A; CA2216034A1; CA2216034C

Abstract

A safety edge (20) for an electrically operated door includes a female housing strip (22), a male actuator strip (24) and means (32) for attaching the safety edge (20) to an edge (34) of the door (36). The female housing strip (22) has an interior cavity (30) in which is positioned a first electrical contact (52). The male actuator strip (24) has a second electrical contact (70). The male actuator strip (24) is telescopically received in the female housing strip (22). The male actuator strip (24) is movable between a first position in which the second electrical contact (70) is spaced from the first electrical contact (52) and a second position in which the second electrical contact (70) engages the first electrical contact (52) to complete a normally open circuit.

Description

SAFETY EDGE FOR AN ELECTRICALLY OPERATED DOOR

FIELD OF THE INVENTION

The present invention relates to a safety edge for an electrically operated door.

BACKGROUND OF THE INVENTION

Electrically operated doors, especially overhead doors, are inherently dangerous. During their downward travel mode, overhead doors are capable of trapping and exerting extreme force upon any object obstructing their path of travel. Therefore, a triggering device is placed upon the lower lead edge of the door which serves to reverse the direction of travel of the overhead door should an object obstruct the door's path of travel. These triggering devices are known as safety edges, although they are also referred to as reversing systems or reversing bars.

One common type of safety edge is a pneumatic system. A gum- hose is used to force air to a diaphragm operated switch. The diaphragm, when aroused by the force of said air, touches a set of electrical points together. Pneumatic systems have a number of inherent problems. The diaphragm operated switch is hidden from view and is, therefore, difficult to inspect for routine maintenance. The gum-hose has a tendency to crack, rot and leak; thereby rendering the system ineffective. Should the door encounter a narrow obstruction during downward travel, a pneumatic reversing system does not always transmit sufficient air through said gum-hose to operate the diaphragm switch. The longer the hose used (i.e. for larger or wider doors), the less effective pneumatic systems become, due to outward deflection of the longer gum-hose, reducing airflow to said diaphragm. This is especially evident when the gum- hose is compressed furthest from said diaphragm switch. On very slow moving doors, the operating capabilities of this switch are extremely limited, due to a reduced force of airflow to said diaphragm.

A more reliable and widely used system is the mechanical safety edge system. Mechanical safety edge systems consist of a metal rail attached to the lead edge of a door section by a hinged attachment system. The mechanical safety edge relies upon gravity to disengage one or more electric switches fastened to the inner face of a bottom section of door. The metal rail pivots upwardly about its hinges upon striking an object in its path of travel. The switches are positioned to be struck by the metal rail or its linkages as it pivots. Although mechanical systems are far more reliable than pneumatic systems, they also have inherent drawbacks. The weight of the metal rail makes it difficult to attach to new lightweight doors and also causes counterbalancing problems. The linkages tend to wear or come out of alignment with the switches they are supposed to contact, thus causing the safety edge to malfunction.

A third style of safety edge is the compressible electrical contact system. This system consists of thin ribbons of copper tape, separated by foam rubber strips. The foam rubber strips are uniformly perforated, and when compressed allow the ribbons of copper tape to contact, sending an electrical signal. As with the other systems described above, this system has inherent defects. The system is housed in a canvas and/or rubber sheath. If the sheath becomes torn, cracked or perforated, the incursion of moisture creates a short in the electrical system. This type of reversing bar is also extremely expensive, and has to be manufactured to suit the length of each individual door size on which it is to be used. This presents stocking problems, as well as marketing concerns.

For these reasons the compressible electrical contact system is not as widely used a system as either the pneumatic or mechanical safety edges.

A fourth style of safety edge is similar to both the pneumatic and compressible electrical contact systems described above, and consists of a deformable member positioned along the bottom edge of the door. The deformable member carries an electrical contact which engages a second electrical contact mounted on the bottom of the door when the door encounters an obstruction and the deformable member is deformed. One disadvantage of this system is that the deformable member, which is often made from plastic or rubber, is prone to cracking, rotting and leaking (as in the pneumatic system), with the result first, that the deformable member may cease to function properly and second, that the electrical contacts may become exposed to dirt and moisture and thus become fouled. A second disadvantage of this system is that the size and configuration of the deformable member is limited by the requirement that it must provide for the electrical contacts to be separated when the deformable member is not deformed and also provide for the electrical contacts to be engaged when the deformable member is deformed. This disadvantage is particularly significant in circumstances where the deformable member also serves to provide a seal between the door and the floor when the door is closed. SUMMARY OF THE INVENTION

What is required is an alternative safety edge for an electrically operated door that obviates some or all of the problems present in the prior art.

According to the present invention there is provided a safety edge for an electrically operated door which includes a female housing strip and a male actuator strip. The female housing strip has an interior cavity in which is positioned at least one of a first electrical contact means. The male actuator strip has at least one of a second electrical contact means. The male actuator strip is telescopically received in the female housing strip. In a preferred embodiment of the invention, the male actuator strip is telescopically received in the interior cavity of the female housing strip. The male actuator strip is movable between a first position in which the second electrical contact means is spaced from the first electrical contact means and a second position in which the second electrical contact means engages the first electrical contact means to close or complete a normally open circuit. Means is provided for attaching the safety edge to an edge of a door. In the preferred embodiment of the invention, means are provided for attaching the female housing strip to an edge of a door. Alternatively, the male actuator strip may be attached to an edge of a door.

In the preferred embodiment, each female housing strip and male actuator strip together comprise a safety edge unit, and a plurality of safety edge units are connected together to form a complete safety edge. In this embodiment, the safety edge further comprises a connector comprising at least one connective member for connecting adjacent safety edge units together both structurally and electrically. More particularly, in the preferred embodiment, each female housing strip of the plurality of safety edge units has opposed ends, adjacent female housing strips have adjacent opposed ends, and the connector connects the adjacent opposed ends of the adjacent female housing strips.

Each female housing strip may have an interior wall, an exterior wall and a plurality of channels disposed between the interior wall and the exterior wall, and the connector may comprise at least one connective member insertable into at least one of the plurality of channels at the adjacent opposed ends of the adjacent female housing strips. Preferably the channels extend between the opposed ends of the female housing strip and preferably the connector comprises at least one connective member for connecting the safety edge units together structurally and comprises at least one connective member for connecting the safety edge units together electrically.

The first electrical contact means may extend the full length of the female housing strip or may be positioned intermittently along the female housing strip. Preferably, however, the first electrical contact means preferably comprises a pair of first electrical contacts. Preferably, one of the pair of first electrical contacts is positioned at one of the opposed ends of the female housing strip and another of the pair of first electrical contacts is positioned at another of the opposed ends of the female housing strip, and preferably the pair of first electrical contacts is electrically connected by using conductive material such as wiring, metal strips or by other means known in the art.

The first electrical contact means may comprise a positive electrical contact and a negative electrical contact in spaced relation, and the second electrical contact means may comprise a bridge contact so that when the male actuator strip is in the second position the bridge contact spans between the positive electrical contact and the negative electrical contact to close the normally open circuit. The second electrical contact means may extend the full length of the male actuator strip or it may be positioned intermittently along the male actuator strip as long as the second electrical contact means can engage the first electrical contact means when the male actuator strip is in the second position. The male actuator strip may also be comprised in whole or in part of conductive material such as metal so that the male actuator strip itself can function as the second electrical contact means.

In the preferred embodiment, the female housing strip is a "C" channel in cross section and the male actuator strip is telescopically received within the "C" channel. The safety edge may also comprise a stop means to prevent the male actuator strip from being withdrawn from the female housing strip. In the preferred embodiment, the stop means comprises internal shoulders in the interior cavity of the female housing strip which are adapted to engage external shoulders on the male actuator strip when the second electrical contact means is spaced from the first electrical contact means by a predetermined distance. Other forms of stop means may, however, be utilized in the invention.

The safety edge may also comprise biasing means to bias the male actuator strip toward the first position. In the preferred embodiment, the biasing means comprise coil springs which are positioned between the male actuator strip and the female housing strip in the interior cavity of the female housing strip. In the preferred embodiment, these coil springs are received in pockets located on the male actuator strip. Other forms of biasing means may, however, be used in the invention as long as they provide the specified biasing function. Such alternative biasing means may include other types of springs or other resilient material such as foam rubber or may even comprise a form of pneumatic or hydraulic dampening system.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of the invention will become more apparent from the following description in which reference is made to the appended drawings, wherein:

FIGURE 1 is a pictorial view of a safety edge constructed in accordance with the teachings of the invention;

FIGURE 2 is a pictorial view of a female housing strip for the safety edge illustrated in FIGURE 1;

FIGURE 3 is a pictorial view of a male actuator strip for the safety edge illustrated in FIGURE 1;

FIGURE 4 is a pictorial view of a first electrical contact assembly for the female housing strip illustrated in FIGURE 2;

FIGURE 5 is a partially cut-away pictorial view of the safety edge illustrated in FIGURE 1, with the endblock removed;

FIGURE 6 is a pictorial view of an endblock for the safety edge illustrated in FIGURE 1;

FIGURE 7 is a pictorial view of a connector for use between two adjacent safety edge units of the safety edge illustrated in FIGURE 1, with gasket and connective members;

FIGURE 8 is a pictorial view of an end cover plate for the safety edge illustrated in FIGURE 1; FIGURE 9 is a pictorial view of a dust plug for the safety edge illustrated in FIGURE 1;

FIGURE 10 is a pictorial view of the safety edge illustrated in FIGURE 1 with end cover plate, dust plug and weather strip attached;

FIGURE 11 is a pictorial view of the safety edge illustrated in FIGURE 10 attached to a typical electrically operated overhead door; and

FIGURE 12 is a partially cut-away detailed pictorial view of the safety edge as illustrated in FIGURE 11.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The preferred embodiment of safety edge, generally identified by reference numeral 20, will now be described with reference to FIGURES 1 through 12.

Referring to FIGURES 1 and 5, the key components of safety edge 20 include an elongate female housing strip 22 and an elongate male actuator strip

24. Referring to FIGURE 11, the length of female housing strip 22 and male actuator strip 24 can be equivalent to the width of any overhead door. In actual practice, female housing strip 22 and male actuator strip 24 will be made in safety edge units of standard lengths with a plurality of safety edge units being joined to make up any required width of safety edge 20, as will hereinafter be further explained. Female housing strip 22 is separately illustrated in FIGURE 2. Male actuator strip 24 is separately illustrated in FIGURE 3. It will be understood that the following description of safety edge 20 as employed on an overhead door bottom section is by way of example only, as the safety edge of the present invention may also be advantageously employed in other applications, such as, rolling steel door bottom rails, rolling shutter door bottom bars, as well as gates and sliding panels, and the like.

Referring to FIGURE 11, each female housing strip 22 has opposed ends 26. Referring to FIGURE 2, each female housing strip 22 has a "C" channel body 28 which defines an interior cavity 30. "C" channel body 28 has an integrally formed vertically extending attachment flange 32. Referring to FIGURE 12, attachment flange 32 serves as means for attaching female housing strip 22 to an edge 34 of a door 36. Alternatively, the attachment flange 32 may be formed with or otherwise connected to the male actuator strip 24 so that the male actuator strip 24 may be attached to an edge 34 of a door 36.

Referring to FIGURE 2, "C" channel body 28 has an interior wall 38, an exterior wall 40, and a plurality of channels 42, 44 and 46 disposed between interior wall 38 and exterior wall 40. Each of channels 42, 44, and 46 extend between opposed ends 26. Channels 46 have longitudinally extending slots 47, the purpose of which will hereinafter be further described. Attachment flange 32 and exterior walls 40 have longitudinally extending exterior reinforcing ribs 48. It is preferred that female housing strip 22 and, in particular, attachment flange 32 be constructed of a lightweight plastic material. This enables portions of attachment flange 32 to be cut away, to accommodate a variety of obstacles, while still maintaining adequate support for female housing strip 22. Interior cavity 30 of female housing strip 22 has internal shoulders 50.

Within interior cavity 30 is positioned first electrical contact means 52. First electrical contact means 52 can take a variety of forms, as long as it is compatible with a second electrical contact means 54 to complete a normally open circuit, as will hereinafter be further described.

In the preferred embodiment, first electrical contact means 52 includes a pair of first electrical contacts, each of the first electrical contacts comprising a positive electrical contact 52a and a negative electrical contact 52b in spaced relation. Positive electrical contact 52a and negative electrical contact 52b are separately illustrated in FIGURE 4. One of the pair of first electrical contacts is positioned at each of the opposed ends of the female housing strip 22.

Each of the pair of first electrical contacts comprising positive electrical contact 52a and negative electrical contact 52b consists of two copper strips formed into a clip-form body 54. To each clip-form body 54 is connected insulated conductive wires 56. These conductive wires 56 extend along the length of the female housing strip 22 to connect the pair of first electrical contacts electrically. It is preferred that an insulating gasket 58 be placed so as to maintain spacing between clip-form body 54 and conductive wires 56. Referring to FIGURE 2, clip-form body 54 is used to clip positive electrical contact 52a and negative electrical contact 52b onto opposed ends 26 of female housing strip 22. When clipped in position, positive electrical contact 52a and negative electrical contact 52b are accessible for electrical contact from both interior cavity 30 and from channels 42. Referring to FIGURE 11, male actuator strip 24 is generally elliptical in transverse section and has opposed ends 64. Referring to FIGURE 3, male actuator strip 24 has a top edge 66 and external shoulders 68 which are spaced toward top edge 66. Top edge 66 has second electrical contact means 70 at each of opposed ends 64. Second electrical contact means 70 is preferably a "bridge" contact that spans between positive electrical contact 52a and negative electrical contact 52b when the male actuator strip 24 is in a second position, as hereinafter will be further described. Pockets 72 are positioned at intervals along top edge 66. Spring 74 are received in and protrude from pockets 72.

Referring to FIGURE 5, male actuator strip 24 is telescopically received within the interior cavity 30 of female housing strip 22. Male actuator strip 24 is movable between a first position in which second electrical contact means 70 is spaced from first electrical contact means 52 and a second position in which second electrical contact means 70 engages first electrical contact means 52 to close a normally open circuit. Springs 74 serve to bias male actuator strip 24 toward the first position. External shoulders 68 on male actuator strip 24 engage internal shoulders 50 within interior cavity 30 of female housing strip 22 to prevent male actuator strip 24 from being withdrawn from female housing strip 22 when in the first position. Male actuator strip 24 moves to the second position to cause second electrical contact means 70 to come into contact with first electrical contact means 52 when an obstruction is encountered in its path of travel. Having first electrical contact means 52 at each of opposed ends 26 of female housing strip 22 and second electrical contact means 70 at each of opposed ends 64 of male actuator strip 24 enables each safety edge unit comprising the safety edge 20 to operate in a safe manner even when struck at one end only.

In the preferred embodiment, the male actuator strip 24 is formed of the same material as the female housing strip 22, such as a lightweight plastic material. The male actuator strip 24 may, however, be formed in whole or in part from a conductive material such as metal so that the male actuator strip 24 itself functions as the second electrical contact means 70.

Referring to FIGURE 6, an endblock 78 is illustrated. Preferably each safety edge unit includes an endblock 78 at each of the opposed ends of the female housing strip 22 to provide strength to the female housing strip 22 and to assist in maintaining the male actuator strip 24 in its proper orientation within the interior cavity 30 of the female housing strip 22. Referring to FIGURE 1, each endblock 78 is attached to the female housing strip 22 with assembly screws 80.

Referring to FIGURE 2, body 28 of female housing strip 22 includes two sidewall access ports 76 at each of opposed ends 26 and referring to FIGURE 1, each endblock 78 may serve as a conduit to the access ports 76 for the conductive wires 56. The access ports are normally covered with cover plugs 82, but to provide access to conductive wires 56 in order to facilitate formation of an electrical circuit between the safety edge 20 and an electrical door opener 86, cover plug 82 may be replaced with a rubber grommet 84 through which said conductive wires 56 may protrude for electrical connection to the electrical door opener 86.

Referring to FIGURE 11, the electrical circuit is formed by connecting conductive wires 56 to the electrical door opener 86 by means of an electrical cord 88. In the preferred embodiment, the conductive wires 56 for each safety edge unit extend between and terminate at each clip form body 54 comprising the pair of first electrical contacts, except as may be required to facilitate the formation of the electrical circuit between the safety edge 20 and the electrical door opener 86, in which case the conductive wires 56 also extend through an endblock 78 and through an access port 76, where they may be connected to the electrical cord 88 which in turn is connected to the electrical door opener 86.

As indicated, safety edge 20 is preferably modular and is preferably comprised of a plurality of safety edge units connected together both structurally and electrically. Referring to FIGURE 11, two or more substantially identical safety edge units when coupled together can achieve a required length of safety edge 20 to correspond to the length of an edge 34 of door 36 on which they are to be installed. Each safety edge unit is constructed in such a manner so as to allow its use individually for door sections of small length or in a plurality of safety edge units connected together for use on door sections of greater length.

Referring to FIGURES 2 and 7, structural and electrical connection between two identical safety edge units is in the preferred embodiment accomplished using a connector comprising copper interlocks 90 and plastic alignment plugs 92 as connective members. Copper interlocks 90 extend through a gasket 94 into channels 42 of female housing strip 22 where they make an electrical connection with electrical contacts 52a and 52b. In order to prevent copper interlocks 90 from going completely into channels 42, plastic positioning stops 60 are provided in channels 42 which limit the distance that copper interlocks 90 can be extended into channels 42. Copper interlocks 90 are preferably made of phosphor-copper, commonly used in many high quality electrical switches, to provide durability and conductivity of great reliability.

Plastic alignment plugs 92 similarly extend into channels 44. Plastic alignment plugs 92 provide a structural connection between adjacent safety edge units which helps to maintain the alignment of a female housing strip 22 of one safety edge unit with a female housing strip 22 of a next adjoining safety edge unit. _.

Referring to FIGURE 8, an optional end cover plate 96 is illustrated. End cover plate 96 has protruding plugs 98 that are adapted to be received in channels 44 of female housing strip 22. Referring to FIGURE 10, when connection to an adjacent safety edge unit is not required, end cover plate 96 may be used to complete the terminal end of a female housing strip 22. Referring to FIGURE 9, an optional foam rubber dust plug 100 is illustrated. Referring to FIGURE 10, dust plug 100 may be used to complete any or all of the opposed ends 64 of a male actuator strip 24. Dust plug 100 is secured in position by a screw (not shown). Referring to FIGURE 10, it is preferred that a rubber weatherstrip 102 be attached to female housing strip 22 covering male actuator strip 24. This weatherstrip 102 prevents debris from entering into interior cavity 30 of female housing strip 22 and may also function to provide a seal between the door edge 34 and the floor when the door 36 is closed. Weatherstrip 102 is retained in channels 46 and extends out through slots 47. Weatherstrip 102 is easily slid into position by sliding along slot 47 from one of opposed ends 64.

The use and operation of safety edge 20 will now be described with reference to FIGURES 1 through 12. Referring to FIGURE 11, a plurality of safety edge units are secured in end to end relation along edge 34 of door 36 using connectors as depicted in FIGURE 7 to form a complete safety edge 20. Referring to FIGURE 12, each safety edge unit is secured to edge 34 of door 36 by inserting screws 104 through attachment flange 32. Attachment flange 32 may be cut away as required to avoid obstacles, such as bottom lifting fixture 106.

Referring to FIGURE 7, the end to end connection of adjacent safety edge units is accomplished using connectors by extending copper interlocks 90 into channels 42 of female housing strip 22 where they make an electrical connection with electrical contacts 52. Plastic alignment plugs 92 similarly extend into channels 44 to provide a structural connection and to add stability.

Referring to FIGURE 5, male actuator strip 24 moves to the second position to cause second electrical contact means 70 to come into contact with first electrical contact means 52 when an obstruction is encountered in its path of travel. The engagement of the second electrical contact means 70 and the first electrical contact means 52 completes a previously open electrical circuit which includes the electrical door opener 86, the electrical cord 88, the conductive wires 56 and the first electrical contact means 52. The electrical contact between second electrical contact means 70 and first electrical contact means 52 can be made at either of opposed ends 64 and 26, respectively, which enables each safety edge unit to operate independently and in a safe manner even when struck at one end only.

Referring to FIGURE 11, using a plurality of safety edge units in the safety edge 20 also assists in improving the seal between the door edge 34 and the floor when the door 36 is closed by virtue of the independent action of each male actuator strip 24 in each safety edge unit. This independent action also better accommodates an angular drainage slope on a floor because the telescoping movement of a relatively short length of male actuator strip 24 will more easily follow an angled floor line when deflected by the closing of the door 36.

It will be apparent to one skilled in the art that modifications may be made to the illustrated preferred embodiment without departing from the spirit and scope of the invention as hereinafter defined in the claims. For example and as discussed above, the safety edge 20 may be configured so that the male actuator strip 24 includes means for attaching the safety edge to a door and the female housing strip 22 is movable relative to the male actuator strip 24 between a first position in which the second electrical contact means 70 is spaced from the first electrical contact means 52 and a second position in which the second electrical contact means 70 engages the first electrical contact means 52 to form a complete electrical circuit.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A safety edge for an electrically operated door, comprising:

(a) a female housing strip having an interior cavity in which is positioned at least one first electrical contact means;

(b) a male actuator strip having at least one second electrical contact means, the male actuator strip being telescopically received in the female housing strip, the male actuator strip being movable between a first position in which the second electrical contact means is spaced from the first electrical contact means and a second position in which the second electrical contact means engages the first electrical contact means to close a normally open circuit; and

(c) means for attaching the safety edge to an edge of the door.

2. The safety edge as defined in Claim 1, wherein the safety edge comprises a safety edge unit, and wherein a plurality of safety edge units are connected together.

3. The safety edge as defined in Claim 2, further comprising a connector comprising at least one connective member for connecting adjacent safety edge units together both structurally and electrically.

4. The safety edge as defined in Claim 3, wherein each female housing strip of the plurality of safety edge units has opposed ends, wherein adjacent female housing strips have adjacent opposed ends, and wherein the connector connects the adjacent opposed ends of the adjacent female housing strips.

5. The safety edge as defined in Claim 4, wherein each female housing strip has an interior wall, an exterior wall and a plurality of channels disposed between the interior wall and the exterior wall, the channels extending between the opposed ends of the female housing strip, and wherein the connector comprises at least one connective member insertable into at least one of the plurality of channels at the adjacent opposed ends of the adjacent female housing strips.

6. The safety edge as defined in Claim 4 or 5, wherein the first electrical contact means comprises a pair of first electrical contacts positioned in the interior cavity of each female housing strip, one of the pair of first electrical contacts positioned at one of the opposed ends of the female housing strip and another of the pair of first electrical contacts positioned at another of the opposed ends of the female housing strip, and wherein the pair of first electrical contacts is electrically connected.

7. The safety edge as defined in Claim 1 or 4, wherein the first electrical contact means includes a positive electrical contact and a negative electrical contact in spaced relation, and the second electrical contact means on the male actuator strip includes at least one bridge contact that spans between the positive electrical contact and the negative electrical contact to close the normally open circuit.

8. The safety edge as defined in Claim 1, wherein the female housing strip has opposed ends, wherein one of the first electrical contact means is positioned at each of the opposed ends of the female housing strip, wherein the male actuator strip has opposed ends, and wherein one of the second electrical contact means is positioned at each of the opposed ends of the male actuator strip such that one of the first electrical contact means is engagable with one of the second electrical contact means to close the normally open circuit at either of the opposed ends of the female housing strip.

9. The safety edge as defined in Claim 1 or 4, wherein the female housing strip is a "C" channel.

10. The safety edge as defined in Claim 1 or 4, wherein a stop means prevents the male actuator strip from being withdrawn from the female housing strip.

11. The safety edge as defined in Claim 1 or 4, wherein biasing means are disposed between the female housing strip and the male actuator strip to bias the male actuator strip toward the first position.

12. The safety edge as defined in Claim 1, wherein the female housing strip has opposed ends, an interior wall, an exterior wall, and a plurality of channels disposed between the interior wall and the exterior wall, the channels extending between the opposed ends.

13. The safety edge as defined in Claim 1 or 4, wherein the female housing strip has longitudinally extending exterior reinforcing ribs.

14. A safety edge for an electrically operated door, comprising:

(a) a "C" channel female housing strip having an interior cavity, opposed ends, an interior wall, an exterior wall, and a plurality of channels disposed between the interior wall and the exterior wall, the channels extending between the opposed ends, a first electrical contact positioned within the interior cavity at both the opposed ends, wiring extending along at least one of the plurality of channels connecting the first electrical contact at each of the opposed ends, each of the first electrical contacts including a positive electrical contact and a negative electrical contact in spaced relation;

(b) a male actuator strip having opposed ends, a second electrical contact including a bridge contact positioned at both of the opposed ends, the male actuator strip being telescopically received in the female housing strip, the male actuator strip being movable between a first position in which the second electrical contact is spaced from the first electrical contact and a second position in which the bridge contact of one of the second electrical contacts spans between the positive electrical contact and the negative electrical contact of one of the first electrical contacts to close a normally open circuit;

(c) means for attaching the safety edge to an edge of the door;

(d) biasing means being disposed between the female housing strip and the male actuator strip to bias the male actuator strip toward the first position; and

(e) stop means preventing the male actuator strip from being withdrawn from the female housing strip when in the first position.

15. In combination: (a) a door having an edge;

(b) a safety edge secured to the edge of the door, the safety edge comprising:

(i) a plurality of modular "C" channel female housing strips, each of the female housing strips having an interior cavity, opposed ends, an interior wall, an exterior wall, and a plurality of channels disposed between the interior wall and the exterior wall, the channels extending between the opposed ends, a pair of first electrical contacts positioned within the interior cavity, one of the pair of first electrical contacts at one of the opposed ends and another of the pair of first electrical contacts at another of the opposed ends, wiring extending along at least one of the plurality of channels connecting the pair of first electrical contacts;

(ii) at least one connector comprising a plurality of connective members insertable into the plurality of channels at one of the opposed ends of each of two female housing strips to structurally and electrically connect adjacent female housing strips in end to end relation; and

(iii) a plurality of modular male actuator strips, each male actuator strip having opposed ends, a pair of second electrical contacts positioned on the male actuator strip, one of the pair of second electrical contacts at one of the opposed ends and another of the pair of second electrical contacts at another of the opposed ends, one of the plurality of male actuator strips being telescopically received in each of the plurality of female housing strips, each male actuator strip being movable between a first position in which each of the pair of second electrical contacts is spaced from the first electrical contacts and a second position in which at least one of the pair of second electrical contacts engages at least one of the pair of first electrical contacts to close a normally open circuit.