Abstract:
A fire alarm pull station includes a cover which must be opened to reach a fire alarm actuating handle, and an audio pull station alarm triggered by opening the cover. Once triggered, the pull station alarm remains on until reset, which reset requires using a tool in a first embodiment or a key in a second (or key lock) embodiment. The tool or key preferably allows the pull station to be opened to reset the pull station alarm. The cover may further be blocked from closing after being opened, and may only be closed after opening the pull station to reset a blocking mechanism. The pull station alarm is preferably an audio alarm residing in the pull station and the pull station may be hard wired to the fire alarm or wireless. The presence of the pull station alarm serves to deter false alarm setting.

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates to pull stations for activating fire alarms and in particular to a pull station with an audio deterrent to reduce false alarm setting. 
   Fire alarm pull stations are commonly used in public places to provide a means for sounding an alarm when a fire occurs. Unfortunately, pranksters often set off false fire alarms as jokes. The results of such false alarms may be both a disruption of normal activities in the area of the alarm and an unnecessary response by a fire company. Setting a false alarm generally results in a number of local alarm bells sounding, but there is often no immediate effect drawing attention to the activated pull station. 
   BRIEF SUMMARY OF THE INVENTION 
   The present invention addresses the above and other needs by providing a fire alarm pull station including a cover which must be opened to reach a fire alarm actuating handle, and an audio alarm triggered by opening the cover. Once triggered, pull station alarm remains on until reset using a tool or key. The pull station alarm is preferably an audio alarm contained in the pull station. The pull station alarm serves to deter false alarm setting. 
   In accordance with one aspect of the invention, there is provided a fire alarm pull station comprising a pull station body and a pull station cover. The pull station cover is attached to the pull station body and resides over a fire alarm actuator, wherein the pull station cover has a cover closed position preventing access to the fire alarm actuator, and the pull station cover has a cover open position allowing access to the fire alarm actuator. A latch holds the pull station body in a body closed position and the body may be opened using either a tool or a key. A pull station alarm is configured to actuate when the pull station cover moves from the cover closed position to the cover open position and may be de-actuated after opening the pull station body from the body closed position to a body open position. 
   In accordance with another aspect of the invention, there is provided a fire alarm pull station including a pull station body and a pull station cover. A fire alarm actuator is attached to the pull station body to actuate the fire alarm. The pull station cover is pivotally attached to the pull station body and resides over the fire alarm actuator, wherein the pull station cover has a cover closed position preventing access to the fire alarm actuator and the pull station cover has a cover open position allowing access to the fire alarm actuator. A plunger resides in the pull station body and is biased towards an extended position. The plunger is held in a retracted position by the pull station cover when the pull station cover is in the cover closed position and the plunger is released to the extended position when the pull station cover is in the cover open position. The plunger restricts moving the pull station cover from the cover open position to the cover closed position when the plunger is in the extended position. A pull station alarm is configured to actuate when the pull station cover moves from the cover closed position to the cover open position and may be de-actuated after using either a tool or a key to open the pull station body. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
     The above and other aspects, features and advantages of the present invention will be more apparent from the following more particular description thereof, presented in conjunction with the following drawings wherein: 
       FIG. 1A  is a perspective view of a fire alarm pull station according to the present invention. 
       FIG. 1B  is a front view of the fire alarm pull station according to the present invention. 
       FIG. 2  depicts the pull station with a pull station cover partially open. 
       FIG. 3  depicts the pull station with the pull station cover fully open. 
       FIG. 4  depicts the pull station with the pull station cover fully open and a fire alarm handle pulled. 
       FIG. 5  is a rear view of the pull station with the pull station body open. 
       FIG. 6  is a rotated rear view of the pull station with the pull station body open. 
       FIG. 7  is a perspective rear view of the pull station from the left rear. 
       FIG. 8  is a perspective rear view of the pull station from the right rear. 
       FIG. 9  is a second pull station with a key lock according to the present invention. 
       FIG. 10  is a first electrical circuit of the pull station. 
       FIG. 11  is a second electrical circuit of the pull station. 
       FIG. 12  shows elements of a first wireless alarm circuit. 
   

   Corresponding reference characters indicate corresponding components throughout the several views of the drawings. 
   DETAILED DESCRIPTION OF THE INVENTION 
   The following description is of the best mode presently contemplated for carrying out the invention. This description is not to be taken in a limiting sense, but is made merely for the purpose of describing one or more preferred embodiments of the invention. The scope of the invention should be determined with reference to the claims. 
   A front perspective view of a fire alarm pull station  10  according to the present invention is shown in  FIG. 1A , and a straight front view of the fire alarm pull station  10  is shown in  FIG. 1B . The pull station  10  includes a pull station body  11  and pull station cover  12 . The cover  12  is pivotally attached to the body  11  by cover pivots  14  (two cover pivots  14  reside on opposite the sides of the body  11 ). A lock  16  on an exposed front surface of the body  11  is provided to open the body  11  for opening the body  11 . The lock  16  may be actuated by either a tool (for example an allen wrench) or a key for a key lock version  10   a  (see  FIG. 9 ). A warning  18  is provided to warn pranksters of a pull station alarm which will sound if the cover  12  is lifted. 
   The pull station  10  with the pull station cover  12  partially open is depicted in  FIG. 2 . When the cover  12  is opened (or pivoted) about the cover pivots  14 , an edge  12   a  of the cover  12  slides past a plunger  24  and the plunger  24  is released to an extended position indicated by arrow  23  orthogonal to the motion of the edge  12   a . The plunger  24  thus extended blocks closing the cover  12 . Further, the plunger  24  may be blocked from retracting into the case  11  by a pull station alarm switch  28  (see  FIG. 5 ) which is preferably a push switch. Therefore, once the cover  12  is opened, it can not be simply closed and can not be closed without first depressing the plunger  24  orthogonally to the motion of the edge  12   a  sufficiently to allow the edge  12   a  to pass over the plunger  24 . 
   The pull station  10  with the pull station cover  12  fully open is depicted in  FIG. 3 . In the cover closed position (see  FIGS. 1A and 1B ), the cover  12  prevents access to a handle  20 , and in the cover open position, the cover  12  allows access to the handle  20 . The handle  20  cooperates with a fire alarm switch  34  (see  FIG. 5 ) to activate the alarm bell  38  (see  FIGS. 9 and 10 ). The pull station  10  is depicted with the pull station cover  12  fully opened and handle  20  pulled in  FIG. 4 . 
   A rear view of the pull station  10  with the pull station body  11  opened by pivoting a back plate  39  away from the body  11  is shown in  FIG. 5 , and a rotated perspective rear view of the opened pull station  10  is shown in  FIG. 6 . The body  11  contains a switch actuator  24   a  attached to the plunger  24 . The plunger  24  is urged toward an extended position indicated by the arrow  23  by a leaf spring  25 , and may alternatively be urged toward the extended position by a coil spring, or any other type of spring. The switch actuator  24   a  cooperates with the pull station alarm switch  28 , which is preferably a push switch, to turn on the pull station alarm when the cover  12  is opened. When the plunger  24  is in the retracted position, the switch actuator  24   a  is aligned with the pull station alarm switch  28  and urges the pull station alarm switch  28  into an OFF position. When the plunger  24  is in the extended position, the switch actuator  24   a  is displaced from the pull station alarm switch  28  and the pull station alarm switch  28  adapts an ON position. 
   The pull station alarm is preferably an audio alarm  26  provides a pull station alarm to deter pranksters. The audio alarm  26  may be a buzzer and preferably produces a piercing warning sound to prevent false alarm setting, and more preferably a 68/100 dB alarm measured at one foot. For example, a Peizo-A-Lert PAL-328N buzzer made by AMESCO in St. Louis, Mo. The audio alarm  26  is aligned with an alarm port  26   a  in a front face of the body  11 . 
   A fire alarm switch  34  is attached to the back plate  39  and is actuated by the handle  20 . The fire alarm switch  34  is preferably a snap action switch, for example, a model number VM0851000F200C1A switch manufactured by E-SWITCH in Brooklyn Park, Minn. Other suitable switches are the model number TMCGD6SP0040C made by C&amp;K Industries, or a model number D3V11G1C25K made by Omron. A key switch  30  (i.e., a key operated electrical switch) is attached to the back plate  39 . The key switch  30  is preferably used to turn off power to electrical elements of the pull station  10  (see  FIG. 10 ). A key port  30   a  in the front face of the body  11  is aligned with the key switch  30  to allow turning the key switch on or off with the pull station body  11  closed. An LED  32  is attached to the back plate  39  and provides an indication that the pull station  10  is receiving power. An LED port  32   a  is provided in the front face of the body  11  to allow the LED to be seen from the front of the pull station  10 . A latch  22  residing inside the body  11  is actuated by the lock  16  (see  FIGS. 1A and 1B ). The latch  22  cooperates with latch receiver  22   a  on the back plate  39  to lock the body  11  in a body closed position. 
   A perspective rear view of the pull station  10  from the left rear is shown in  FIG. 7  and a perspective rear view of the pull station  10  from the right rear is shown in  FIG. 8 . In each view wiring is omitted to provide a clearer illustration, which wiring is shown in  FIGS. 9 and 10  below. Portions of the audio alarm  26 , push switch  28 , key switch  30 , LED  32 , and the fire alarm switch  34  are seen extending through the back plate  39 . Additionally, a terminal block  36  with  4  terminals (see  FIGS. 9 and 10 ) is mounted to a black surface of the back plate  39 . 
   A second pull station  10   a  with a key lock  16   a  replacing the lock  16  is shown in  FIG. 9 . The pull station  10   a  is otherwise like the pull station  10 . Further, the tool or key may directly turn off the pull station alarm without opening the pull station by actuating a switch inside the pull station. 
   A first electrical circuit  50  of the pull station  10  is shown in  FIG. 10 . Conductors  58  (shown as solid lines) carry power between a power source  40  and the terminals T 2  and T 4  of the terminal block  36 . The key switch  30  resides between terminal T 4  and T 1 , connected by conductors  54  (shown as dotted lines). The key switch  30  thus may disconnect (or turn off) electronic components in the pull station  10  from the power source  40 . Conductors  52  (shown as short dashed line) connect the push switch  28  and buzzer  26  in series between the terminal T 1  and a terminal T 2 . When the push switch  28  is closed (and the key switch  30  is in an ON position), power is provided to the buzzer  26  to sound the pull station alarm. Power is additionally provided through the conductors  52  to the LED  32  when ever the key switch  30  is on. 
   An alarm bell circuit is connected by conductors  56  (shown as long dashed lines) connecting the fire alarm switch  34  between terminals T 1  and T 3 . The alarms bell  38  is connected between terminal T 2  (i.e., is connected directly to the power source  40 ) and terminal T 3 . The alarm circuit  50  is a preferred circuit when there is access to two wires from the power source  40  and access to two wires from the alarm bell  38 . 
   A second electrical circuit  60  of the pull station  10  is shown in  FIG. 11 . A battery  42  is connected between the terminal T 4  and the terminal T 2 , thus providing a power source to the pull station  10 , for example, when the pull station is a wireless pull station. The key switch  30  resides between terminal T 4  and T 1 , connected by conductors  54  (shown as dotted lines). Conductors  52  (shown as short dashed line) connect the push switch  28  and buzzer  26  in series between the terminal T 1  and the terminal T 2 . When the push switch  28  is closed (and the key switch  30  is in an ON position), battery power is provided to the buzzer  26  to sound the pull station alarm. Battery power is additionally provided through the conductors  52  to the LED  32  when ever the key switch  30  is on. 
   A second alarm bell circuit is connected by conducts  56  (shown as long dashed lines) serially connecting the fire alarm switch  34  between terminals T 1  and T 3 . Thus, when the key switch  30  is in an ON position, and the fire alarm switch  34  is closed (or on), a circuit is closed between the terminals T 3  and T 4 . The power source  40  is connect by the conductors  52  (shown as solid lines) to terminals T 3  and T 4  of the terminal block  36 , and the alarm bell  38  and the power source  40  are serially connected between the terminal T 3  and the terminal T 4 . Therefore, when the key switch  30  is on, and the fire alarm switch  34  is closed, a circuit is completed between the alarm bell  38  and the power source  40 . In the case of a wireless pull station, closing the circuit between the terminals T 3  and T 4  causes an alarm signal to be transmitted to a separate alarm bell circuit. The conductors  52 ,  54 ,  56 ,  58 , and  62  are preferably electrical wires. The alarm circuit  60  is a preferred circuit when there is access to one wire from the power source  40  and access to one wire from the alarm bell  38 . 
   Elements of a first wireless alarm circuit  64  are shown in  FIG. 12 . The circuit  64  is similar to the circuit  60  (see  FIG. 11 ) with the exception that a transmitter  70  is connected between the terminals T 3  and T 4  replacing the alarm bell  38  and power source  40  in-series connected in-series between the terminals T 3  and T 4 . The alarm bell  38  and power source  40  comprise an alarm bell circuit including a receiver  72  for receiving wireless signals from the transmitter  70 . 
   While the invention herein disclosed has been described by means of specific embodiments and applications thereof, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope of the invention set forth in the claims.