Abstract:
A security alarm sensor for mounting between two corner walls is described comprising a housing unit having a housing base for attachment to the corner walls and a selectively detachable housing cover; a circuit board sized for engagement within the housing unit; first and second openings on opposite sides of the housing base; first and second mounting pins selectively movable within the first and second openings wherein said mounting pins have a length and a range of movement so as to have a first position wherein the mounting pins are totally retracted within the housing unit and a second position wherein said mounting pins extend outwardly from the housing unit sufficiently to pierce the corner walls and securely hold the security alarm sensor in place. The installation of the alarm sensor is usually accomplished by first removing the housing cover from the housing base and detaching the printed circuit board prior to mounting the housing base to the corner of the wall.

Description:
This application is a divisional application Ser. No. 09/781,938 filed on Feb. 12, 2001 now U.S. Pat. No. 6,494,425. 
    
    
     FIELD OF THE INVENTION 
     This invention is generally directed to an apparatus and method for mounting security alarm sensors within a protected premises. More specifically, the apparatus and method of the present invention provides a means for easily connecting a security alarm sensor in a corner of a room with minimal risk to the circuitry and without utilizing any screws, nails or mounting brackets. 
     BACKGROUND OF THE INVENTION 
     Burglaries, and the perceived risk thereof, have continually increased, particularly in crowded urban areas. Thus, an increasing number of businesses and homes are protected by alarm systems. Most alarm systems comprise an alarm control panel; a series of detectors, sensors and/or door/perimeter contacts; and a user-controlled keypad. Most sensors/detectors are strategically placed within a protected premises by a skilled installer so as to maximize the detection of unauthorized intruders while minimizing the risk of false alarms caused by heaters, open windows, pets, etc. Various sensors/detectors exist which can detect the motion or heat caused by an unauthorized intruder when the alarm system is armed. Examples of such sensors/detectors include passive infrared (PIR) sensors, microwave sensors, ultrasonic devices, etc. Many conventional sensors utilize dual technology devices which combine complementary technologies to minimize false alarms. 
     The most effective and least unsightly position for many sensors is in the corner of a room. However, it is often difficult for an installer to securely fasten the sensor in the corner of a room without either utilizing a corner mounting bracket or preventing damage to the housing base or alarm circuitry when awkwardly connecting screws through standard corner mount screw holes. If precise placement of the sensor/detector is not made, its proper functioning is greatly jeopardized. 
     Most conventional security alarm sensors are packaged as an integrated housing unit. This housing unit includes a selectively attached housing base and housing cover with a printed circuit board contained therein. The installer will typically remove the housing cover from the housing base to expose the printed circuit board contained therein. Next, the installer will carefully remove the printed circuit board from the housing base to prepare the housing base for installation to a wall. The printed circuit board is removed to minimize the risk of tools damaging the circuitry thereof. The housing base is either securely fastened in a corner of a room by means of a mounting bracket or by screws inserted through standard corner mount screw holes. In either case, mounting is typically slow and awkward due to the difficulty of inserting screws at an angle while on a ladder. Obviously, in order to securely fasten the housing base to the wall, at least two, and preferably four, corner mounting screws must be used. Once the housing base is in place, the installer will reinsert the printed circuit board and reattach the housing cover. 
     Whenever screws are utilized by an installer, particularly when on a ladder, they are often dropped, lost, etc. requiring even additional installation time and inconvenience for the installer. Thus, labor costs for installation companies are high. Thus, what is lacking in the prior art is a housing unit and method which permits corner mounting without the need for utilizing a corner mounting bracket or any screws whatsoever. Whether mounting brackets or screws are utilized, if the installer needs to reposition the sensor for any reason, the walls will now contain damage due to screw holes. Thus, repair plastering sometimes is warranted. This further increases the costs to installation companies. 
     It is therefore a primary object of the present invention to provide a new and improved method and apparatus for mounting a security alarm sensor to the corner of a wall. 
     It is another object of the present invention to provide a new and improved method and apparatus for mounting a security alarm sensor to the corner of a wall without utilizing mounting brackets or screws. 
     It is yet a further object of the present invention to provide a new and improved method and apparatus for mounting a security alarm sensor to the corner of a wall that, can be easily repositioned without creating any unsightly holes on the walls. 
     Other objects and advantages of the present invention will become apparent from the specification and the drawings. 
     SUMMARY OF THE INVENTION 
     Briefly stated and in accordance with the preferred embodiment of the present invention, a security alarm sensor for mounting between two corner walls is described comprising a housing unit having a housing base for attachment to the corner walls and a selectively detachable housing cover; a circuit board sized for engagement within the housing unit; first and second openings on opposite sides of the housing base; first and second mounting pins selectively movable within the first and second openings wherein said mounting pins have a length and a range of movement so as to have a first position wherein the mounting pins are totally retracted within the housing unit and a second position wherein said mounting pins extend outwardly from the housing unit sufficiently to pierce the corner walls and securely hold the security alarm sensor in place. The installation of the security alarm sensor is usually accomplished by first removing the housing cover from the housing base and detaching the printed circuit board prior to mounting the housing base to the corner of the wall. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     While the specification concludes with claims particularly pointing out and distinctly claiming the subject matter regarded as the invention herein, it is believed that the present invention will be more readily understood upon consideration of the description, taken in conjunction with the accompanying drawings, wherein: 
     FIG. 1 is an exploded view of an alarm sensor in accordance with the present invention which includes a housing unit comprising a housing base and a housing cover, a printed circuit board, and a rotatable mounting disc; 
     FIG. 2 is a schematic illustration of the housing base and the rotatable mounting disc in accordance with the present invention; 
     FIG. 3 is a schematic illustration of the housing base of the present invention being installed between two corner walls; 
     FIG. 4 is a schematic illustration of the back of the housing base of the housing base and rotatable mounting disc in accordance with the present invention wherein mounting pins are in their retractable position; 
     FIG. 5 is a schematic illustration of the back of the housing base of the housing base and rotatable mounting disc in accordance with the present invention wherein mounting pins are in their extended position; 
     FIG. 6 is a cross-sectional view of FIG. 5 taken along reference line  6 — 6 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring first to FIG. 1, an alarm sensor in accordance with the present invention is generally designated by reference numeral  10  and shown in exploded form. A housing unit comprised of a housing base  12  and a housing cover  14  is shown. Within housing base  12  and housing cover  14  is a printed circuit board  16  and a rotatable mounting disc  18 . Although shown as coupled to mounting disc  18 , a first mounting pin  20  and a second mounting pin  22  are typically separate from mounting disc  18  and extend outwardly in generally opposite directions. 
     Printed circuit board  16  is shown as a PIR sensor for illustrative purposes. Thus, printed circuit board  16  includes a PIR sensor element  24  and a PIR lens  26 . Also on printed circuit board  16  are terminal strips  28  and  30 . Terminal strips  28  and  30  are preferably comprised of “speaker-jack style” terminals which simply snap down to secure connecting wires. Thus, no terminal screws are necessary. In the instance where alarm sensor  10  is a PIR sensor, housing cover  14  can also be split in two components to allow for dual focal lengths for the PIR zones. Dual focal lengths are often incorporated in PIR sensors to eliminate false alarms due to pets. It will be noted by those skilled in the art that the mounting apparatus and method of the present invention can be utilized not only for PIR sensors, but also for various security alarm sensors based on microwave technology, ultrasound technology, or any variations thereof. Furthermore, the mounting apparatus and method of the present invention is equally applicable to alarm sensors for fire, smoke, temperature, etc. Additionally, the mounting apparatus and method of the present invention can be utilized on hardwired or wireless sensors. Thus, the actual components shown on printed circuit board  16  are only illustrative; countless variations are possible. 
     Housing base  12  includes corner mount screw hole punch-outs  32 ,  34 ,  36  and  38 . An installer can selectively utilize screws through corner mount screw holes punch-outs  32 ,  34 ,  36  and  38  to mount housing base  12  onto corner walls  40  and  42 . Similarly, housing base  12  illustrates four flat wall mount screw hole punch-outs  44 ,  46 ,  48  and  50 . An installer will selectively utilize flat wall mount screw hole punch-outs  44 ,  46 ,  48  and  50  when the housing base is to be installed onto a flat wall. Finally, housing base  12  also includes a swivel mount punch-out  52  that allows installation so that alarm sensor  10  can be made to slightly rotate. While the alternative utilization of corner mount screw hole punch-outs  32 ,  34 ,  36  and  38 ; flat wall mount screw hole punch-outs  44 ,  46 ,  48  and  50 ; or swivel mount punch-out  52  allows a single housing unit to be incorporated in various applications, a screwdriver is required for all installations. Particularly when a corner mounting is desired, the use of screws and a screwdriver on a ladder is often burdensome. 
     Housing base  12  is adapted to receive rotatable mounting disc  18 , first mounting pin  20 , and second mounting pin  22 . More specifically, housing base  12  includes a first guided groove  54 , a second guided groove  56 , a first guide slot  58  and a second guide slot  60 . As best shown in FIG. 2, first guide slot  58  permits a path upon which first mounting pin  20  can easily travel whereas second guide slot  60  permits a path upon which second mounting pin  22  can easily travel. Based on the proper manipulation of rotatable mounting disc  18  by means of a screwdriver slot  62 , first mounting pin  20  can be made to either retract within or extend beyond a first opening  64  on housing base  12 . Similarly, second mounting pin  22  can be made to either retract within or extend beyond a second opening  66  on housing base  12 . First opening  64  and second opening  66  are typically on respective planes  65  and  67  of housing base  12  which are contoured at approximately 45° angles. This angle permits planes  65  and  67  to rest flatly on corner walls  40  and  42  that generally form a 90° angle. This flush alignment is best seen in FIG.  3 . 
     Before addressing the interconnection between rotatable mounting disc  18  and housing base  12 , and the manipulation of mounting disc  18  to control the selective movement of first mounting pin  20  and second mounting pin  22 , it should be understood that alarm sensor  10  is typically packaged as a interconnected unit. Housing base  12  is snapped together to housing cover  14  with circuit board  16  and mounting disc  18  therein. In order to separate housing base  12  from housing cover  14 , a screwdriver is typically inserted into a slot  68  to release a mounting tab (not shown) that holds housing unit  12  and housing base  14  together. At this stage, printed circuit board  16  is coupled to housing base  12  by means of a circuit board height index tab  70 . When slight pressure is applied to circuit board height index tab  70 , circuit board  16  can be easily removed. Circuit board  16  can be wired at this point so that when ultimately replaced within housing base  14 , the wires can be easily displaced through the housing unit by means of a wire entry punch-out  72 . Obviously, wireless sensors would not require wire entry punch-out  72 . 
     Once housing base  12  and housing cover  14  have been separated and circuit board  16  has been removed, housing base  12  is ready for mounting to walls  40  and  42 . An installer will simply hold housing base  12  at a desired location, insert a screwdriver into screwdriver slot  62  and turn rotatable mounting disc  18  approximately 45°. The rotational movement of mounting disc  18  will result in first mounting pin  20  and second mounting pin  22  simultaneously moving outwardly so as to sufficiently pierce walls  40  and  42  and secure housing base  12  in place. At this point, printed circuit board  16  would be reconnected to housing base  12  by manipulating circuit board index tab  70  and housing cover  14  would be snapped onto housing base  12 . 
     FIGS. 2-6 will assist demonstrating precisely how rotational movement of mounting disc  18  results in appropriate linear movement of first mounting pin  20  and second mounting pin  22  to selectively, but securely, attach alarm sensor  10  to corner walls  40  and  42 . As seen in FIG. 2, rotatable mounting disc  18  includes optional directional arrows  74  and  76  to instruct an installer in the direction rotatable mounting disc  18  should be rotated to connect housing base  12  to walls  40  and  42 . FIG. 2 demonstrates the position wherein rotatable mounting disc  18  has already been turned clockwise so that first mounting pin  20  and second mounting pin  22  extend outwardly from housing base  12 . Instead of utilizing a screwdriver in screwdriver slot  62 , it may be possible to utilize thumb turns  78  and  80  to rotate mounting disc  18 . 
     In the preferred embodiment of the present invention, a mechanism has been provided to prevent over-rotation of mounting disc  18  which would cause damage to first mounting pin  20  and second mounting pin  22 . Referring to FIG. 4, it is shown that rotatable mounting disc  18  includes a first protruding knob  82  and a second protruding knob  84 . First protruding knob  82  travels along first guided groove  54  whereas second protruding knob  84  travels along second guided groove  56 . A first non-protruding engagement end  86  of first mounting pin  20  rests loosely between first protruding knob  82  and a raised portion of mounting disc  18 . Similarly, a second non-protruding engagement end  88  of second mounting pin  22  rests loosely between second protruding knob  84  and a raised edge of mounting disc  18 . First non-protruding engagement end  86  and second non-protruding engagement end  88  preferably extend at approximately 90° angles respectively from the rest of first mounting pin  20  and second mounting pin  22 . 
     FIG. 4 shows the back of housing base  12  and mounting disc  18  in a position wherein first mounting pin  20  and second mounting pin  22  are retracted within housing base  12 . Conversely, FIG. 5 shows the back of housing base  12  and mounting disc  18  in a position wherein first mounting pin  20  and second mounting pin  22  are extended beyond housing base  12 . This difference is caused by an approximately 45° turn of mounting disc  18  from the inside of housing base  12 . As shown in FIG.  4  and FIG. 5, mounting disc  18  has been connected to housing base  12  by pressure mounting tabs  90 ,  92 ,  94  and  96 . While experimentation has shown that mounting disc  18  is most securely attached to housing base  12  by utilizing four pressure mounting tabs, it is also possible to use two pressure mounting tabs. The utilization of pressure mounting tabs is preferred since, should mounting disc  18  break it is easy to attach a new one to the existing housing base without replacing the entire housing unit. However, there are many alternative techniques of connecting mounting disc  18  to housing base  12  that will become apparent to those skilled in the art. 
     FIG. 6 is a cross-sectional view of FIG. 5 taken along reference line  6 — 6  and effectively shows the different components and shapes of components utilized in the preferred embodiment of the present invention. Of significant importance in the preferred embodiment is the fact that not only can housing base  12  be easily installed to corner walls  40  and  42 , but, should the installer have made an error, the device is as easily removable and reinstalled at a new position. The pins are sufficiently narrow so as to cause only negligible damage to any wall. Whether rotating mounting disc  18  to either retract or extend first mounting pin  20  and second mounting pin  22 , first guided groove  54  and second guided groove  56  prevent over-rotation of mounting disc  18  in any direction. Thus, any potential damage to first mounting pin  20  and second mounting pin  22  is eliminated. 
     Although, through experimentation, the rotation of mounting disc  18  has been shown to be the best mode for achieving selective linear movement of first mounting pin  20  and second mounting pin  22  from a first retracted position to a second extended position, the utilization of other means is also foreseen. For instance, the mounting pins can be selectively moved by means of a thumb-controlled, ratcheted device similar to a smaller version of a car jack, by a geared wheel-turn, by a locked collar apparatus, or by other means known in the art for applying sufficient and selective torque to the mounting pins. The various means for achieving selective, linear movement of the mounting pins should be sufficiently small so as not to interfere with the replacement of the printed circuit board on the housing base. 
     It will be apparent from the foregoing description that the present invention provides a new and improved method and apparatus for providing an easy connection of an alarm sensor to the corner of a room with minimal risk to the circuitry and without utilizing of any screws, nails or mounting brackets. While a specific preferred embodiment has been described, many variations may be utilized. For instance, although both first mounting pin  20  and second mounting pin  22  have been shown to incorporate only a single prong, double pronged pins (similar to staples) can be incorporated. Additionally, first mounting pin  20  and second mounting pin  22  can be threaded pins in certain variations. Moreover, while rotatable mounting disc  18  has been shown as being generally circular and of a composite material, it can indeed take various shapes as long as its rotational movement will result in basic linear movement of first mounting pin  20  and second mounting pin  22 . 
     While there has been shown and described what is presently considered to be the preferred embodiment of this invention, it will be obvious to those skilled in the art that various changes and modifications may be made without departing from the broader aspects of this invention. For instance, the preferred embodiment has described a single rotatable mounting disc  18 , which upon proper manipulation, simultaneously moves both first mounting pin  20  and second mounting pin  22 . It is certainly foreseen that separate mounting discs could be utilized for each mounting pin, particularly if the device is wide. Moreover, while a particular means for separating the housing base from the housing cover and the printed circuit board from the housing base has been shown, many variations exist in the art. 
     It is, therefore, aimed in the appended claims to cover all such changes and modifications as fall within the true scope and spirit of the invention.