Abstract:
A manual alarm device including a housing and a displacement element mounted in the housing is provided. The displacement element is moveable between a first position and a second position. Only application of a stable force to the displacement element is configured to move the displaceable element between the first position and the second position.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to Chinese Application Serial No. 201510596532.0, filed Sep. 18, 2015, the entire disclosure of which is incorporated herein by reference. 
       TECHNICAL FIELD 
       [0002]    The disclosure relates to a manual alarm device for an alarm system, and more particularly, to a manually operable manual alarm device that can be actuated and then reset. 
       RELATED ART 
       [0003]    One or more manually operable manual alarm devices are usually incorporated into a fire alarm system, which can be actuated by a person finding a fire, to trigger a fire alarm. Such a manual alarm device traditionally includes an element that can be reached through a window. In order to actuate the fire alarm system, a force is applied to the element to cause the element to move and connect an adjacent switch. A state of the manual alarm device can be visually determined easily through simple visual evaluation on the situation of the element. 
         [0004]    A conventional manual alarm device generally includes a plurality of friction elements. Similarly, other components also exist which are configured to restrict movement of the elements once actuated. The friction elements usually wear out as the time elapses, and are vulnerable to influences of dirt, dust and debris accumulation, and the accumulation may affect functionality of the manual alarm device and require an additional force for actuation. Moreover, the elements in the conventional manual alarm device can be easy to move and do not provide a mechanism for conducting identification between accidental and intentional actuation. As a result, such a manual alarm device has limited reliability. 
       SUMMARY 
       [0005]    According to an embodiment of the disclosure, a manual alarm device is provided, which includes a housing and a displaceable element mounted in the housing. The displaceable element is moveable between a first position and a second position. Only application of a stable force to the displacement element is configured to move the displaceable element between the first position and the second position. 
         [0006]    Other than one or more of the features described above, or as an alternative, in another embodiment, movement of the displaceable element is restricted when the displaceable element is in the second position. 
         [0007]    Other than one or more of the features described above, or as an alternative, in another embodiment, a locking piece is configured to restrict movement of the displaceable element from the second position. 
         [0008]    Other than one or more of the features described above, or as an alternative, in another embodiment, a biasing force produced by a biasing mechanism is configured to restrict movement of the displaceable element from the second position. 
         [0009]    Other than one or more of the features described above, or as an alternative, in another embodiment, an external apparatus is configured to manually release the displaceable element from the second position. 
         [0010]    Other than one or more of the features described above, or as an alternative, in another embodiment, the manual alarm device includes a body having at least one mounting arm, and the body is configured to rotate around the mounting arm. 
         [0011]    Other than one or more of the features described above, or as an alternative, in another embodiment, a high viscosity material is configured to damp movement of the displaceable element. 
         [0012]    Other than one or more of the features described above, or as an alternative, in another embodiment, a part of the at least one mounting arm is received in a bracket, which includes the high viscosity material, of the housing. 
         [0013]    Other than one or more of the features described above, or as an alternative, in another embodiment, a biasing mechanism is mounted to the at least one mounting arm. The biasing mechanism is configured to move the displaceable element from the second position to the first position after the displaceable element is manually released. 
         [0014]    Other than one or more of the features described above, or as an alternative, in another embodiment, the body includes an upper body and a lower body pivotably linked to a toggle rod. 
         [0015]    Other than one or more of the features described above, or as an alternative, in another embodiment, a biasing mechanism is configured to apply a biasing force to the lower body. 
         [0016]    Other than one or more of the features described above, or as an alternative, in another embodiment, the body includes an upper body and a lower body connected by at least one flexible chain. The at least one flexible chain is made of a compliant elastic material. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    When the specification concludes, the gist of the disclosure is particularly indicated and clearly asserted in the claims. Through the following detailed description with reference to the accompanying drawings, the foregoing and other features and advantages of the disclosure are evident, in which: 
           [0018]      FIG. 1  is a schematic view of a building that includes a fire alarm system; 
           [0019]      FIG. 2  is a perspective view of an example of a manual alarm device of a fire alarm system; 
           [0020]      FIG. 3  is a perspective view of a displacement element of a manual alarm device according to an embodiment of the disclosure; 
           [0021]      FIG. 3 a    is a perspective view of part of a displacement element mounted in a housing of a manual alarm device according to an embodiment of the disclosure; 
           [0022]      FIG. 4  is a perspective view of another displacement element according to an embodiment of the disclosure; 
           [0023]      FIG. 4 a    is a side view of the displacement element in  FIG. 4 ; 
           [0024]      FIG. 5  is a perspective view of another displacement element according to an embodiment of the disclosure; and 
           [0025]      FIG. 5 a    is a side view of the displacement element in  FIG. 5 . 
       
    
    
       [0026]    The embodiments of the disclosure as well as advantages and features thereof are described with examples through the detailed description with reference to the accompanying drawings. 
       DETAILED DESCRIPTION 
       [0027]      FIG. 1  illustrates an example of a building  20  that includes a fire alarm system  30 . The fire alarm system  30  includes a plurality of manually operable manual alarm devices  32 , which are located in various positions throughout the building  20 . The plurality of manual alarm devices  32  are operably linked to each other, for example, through a plurality of wires or controllers (not shown). As a result, if one of the plurality of manual alarm devices  32  is actuated to indicate, for example, occurrence of a predetermined emergency of fire, one or more of the manual alarm devices  32  not actuated in other regions of the building  20  can be configured to generate an alarm throughout all or at least part of the building  20 . 
         [0028]    Now referring to  FIG. 2 , an example of configuration of a manual alarm device  32  for use in the fire alarm system  30  in  FIG. 1  is illustrated in more detail. Although the manual alarm device  32  is illustrated and described herein regarding the fire alarm system  30 , configuration of the manual alarm device for use in any type of systems is within the scope of the disclosure. In an illustrated and non-restrictive embodiment, the manual alarm device  32  includes a housing  34  which has a removable front cover  36  including an observation widow  38  formed on a front surface thereof. For example, a displaceable element  40  of a push plate is located in the housing  34 , and can be reached through the observation widow  38 . What is located in the housing  34  and generally adjacent to the displaceable element  40  is a switch (not shown). The displaceable element  40  is manually moveable between a first position and a second position. When the displaceable element  40  moves to the second position, the displaceable element  40  contacts and actuates the switch to indicate an alarm situation. In one embodiment, once actuated, the displaceable element  40  is configured to remain in the second actuated position until an external apparatus is used to manually reset the manual alarm device  32 . For example, a key may be inserted into an orifice formed in the housing  34  to reset the manual alarm device  32  and return the displaceable element  40  to the first un-actuated position. However, in other embodiments, the displaceable element  40  can be configured to automatically return to the first un-actuated position when a force applied thereto is removed. 
         [0029]    Now referring to  FIGS. 3-5 , various embodiments of configuration of a displaceable element  40  for use in the manual alarm device  32  are shown in more detail. In each of  FIGS. 3-5 , the displaceable element  40  generally includes a flat body  42 , which has at least one mounting arm  46  connected to a first end  44  thereof. As illustrated, a first mounting arm  46   a  and a second mounting arm  46   b  are connected to a body  44  and extend away from the body  44  in basically opposite directions. The first and second mounting arms  46   a  and  46   b  are coaxially arranged so that the body  42  is configured to pivot around an axis X defined by the first and second mounting arms  46   a  and  46   b  when the displaceable element  40  is mounted in the housing  34 . 
         [0030]    Each of the displaceable elements  40  described herein is configured to minimize actuation due to high impact and accidental contact. Referring to the displaceable element  40  in  FIGS. 3 and 3   a , when the element  40  is mounted in the housing  34 , the at least one mounting arm  46  is received in a bracket  50 , which includes a high viscosity material, for example, lubricating grease, of the housing  34 . One or more discs  52  (for example, two discs) can be mounted to each of the mounting arms  46  to restrict lateral movement of the displaceable element  40 , especially movement of the mounting arm  46  relative to the bracket  50 . Each disc  52  defines a plane of shearing the lubricating grease. Therefore, the increased number of the discs  52  increases the number of the planes of shearing the lubricating grease, which thus increases damping stiffness of the displaceable element  40 . The high viscosity material is configured to resist sudden rotation of the displaceable element  40  around the axis X of the mounting arms  46   a  and  46   b,  which, for example, is produced by high speed impact when people or things involuntarily impact or otherwise contact the displaceable element  40 . However, the high viscosity material is configured to provide limited resistance to slower and intentional movement of the displaceable element  40 . 
         [0031]    A part of the mounting arm  46  is configured to lock the displaceable element  40  in the second actuated position. In one embodiment, at least one of the discs  52  includes a locking piece  54  configured to restrict movement of the displaceable element  40  once pressed down. As described previously, an external apparatus can be used to unlock the locking piece  54 , so that the displaceable element  40  can freely rotate from the second actuated position to the first un-actuated position. In one embodiment, for example, a biasing mechanism  56  of a torsion spring is mounted around at least one of the mounting arms  46   a  and  46   b.  Once the displaceable element  40  has been unlocked, at least one biasing mechanism  56  is configured to bias the displaceable element  40  back to the first un-actuated position. 
         [0032]    Now referring to the displaceable element  40  shown in  FIGS. 4 and 4   a , the body  42  includes an upper body  60  and a lower body  62  connected by a toggle rod  64 . The lower body  62  is generally received in an opening  66  of the housing  34  (refer to  FIG. 4 a   ). A biasing mechanism  68  may be arranged in the opening  66  and below the lower body  62 . However, in other embodiments, the biasing mechanism  68  may be integrally formed with a part of the lower body  62 , as illustrated. 
         [0033]    In an illustrated and non-restrictive embodiment, the toggle rod  64  includes a plurality of gear portions  70  extending from a first side thereof and a plurality of openings  72  formed in a second opposite side thereof. However, other embodiments in which the toggle rod  64  only includes a single gear portion  70  are also within the scope of the present invention. The first side of the toggle rod  64  is pivotably linked to the upper body  60 , for example, by using a pin, so that the plurality of gear portions  70  are received in a plurality of complementary openings  74  formed in the upper body  60 . Similarly, the second side of the toggle rod  64  is rotatably linked to the lower body  62 , so that a plurality of gear portions  74  extending from the lower body  62  are received in a plurality of adjacent openings  72  of the toggle rod  64 . 
         [0034]    A high viscosity damping material, for example, lubricating grease, is located at an interface between the toggle rod  64  and at least one of the upper body  60  and the lower body  62 . As described previously, the high viscosity material is configured to resist sudden rotation of the displaceable element  40  around the axis X of the mounting arms  46   a  and  46   b,  which, for example, is produced by high speed impact when people or things involuntarily impact or otherwise contact the displaceable element  40 . However, the high viscosity material is configured to provide limited resistance to slower and intentional movement of the displaceable element  40 . When the displaceable element  40  is intentionally actuated, the toggle rod  64  rotates. Rotation of the toggle rod  64  applies a downward force to the lower body  62  to cause the biasing mechanism  68  to compress. A reactive biasing force of the biasing mechanism  68  causes the toggle rod  64  (and thus the displaceable element  40 ) to be locked in a proper position in the second actuated position. 
         [0035]    Now referring to the displaceable element  40  shown in  FIGS. 5 and 5   a , the body  42  similarly includes an upper body  60  and a lower body  62  connected together by at least one flexible chain  80 . Although shown as two flexible chains  80 , any displaceable element  40  including any number of flexible chains  80  is within the scope of the present invention. In an illustrated and non-restrictive embodiment, the lower body  62  includes at least one mounting arm  82  configured to restrict movement of the lower body  62  to rotation around an axis Y defined by the at least one mounting arm  82 . The mounting arm  82  may be basically the same as or different from at least one mounting arm  46  connected to the upper body  60 . 
         [0036]    The at least one flexible chain  80  is made of, for example, a plastic compliant elastic material, and can be connected to the upper and lower bodies  60  and  62  or integrally formed with the upper and lower bodies  60  and  62 . The material of the flexible chain  80  is selected from any suitable material having desired flexibility and rigidity. The suitable material will provide sufficient resistance to cause the at least one chain  80  to be configured to operate as a damping mechanism. In one embodiment, the flexible chain  80  is made of a material the same as that of the upper and lower bodies  60  and  62 , but has a different section. 
         [0037]    The flexible chain  80  is configured to resist sudden rotation of the displaceable element  40  around the axis X of the mounting arms  46   a  and  46   b,  which, for example, is produced by high speed impact when people or things involuntarily impact or otherwise contact the displaceable element  40 . However, the flexible chain  80  is configured to provide limited resistance to slower and intentional movement of the displaceable element  40 . When the displaceable element  40  is intentionally actuated, the upper body  60 , the flexible chain  80  and the lower body  62  rotate to the second actuated position. Stiffness of the flexible chain  80  is configured to lock the displaceable element  40  in the second position until an external apparatus is used to manually reset the manual alarm device  32 . 
         [0038]    The displaceable element  40  disclosed herein has a reduced number of friction elements. In addition, movement of the displaceable element  40  is damped, causing unintentional actuation of the manual alarm device to be significantly reduced. As a result, the overall reliability of the manual alarm device having the displaceable element  40  as described herein is increased. 
         [0039]    Although the disclosure has been described in detail only in combination with a finite number of embodiments, it should be easily understood that the disclosure is not limited to the disclosed embodiments. Moreover, the disclosure can be modified to incorporate any number of transformations, variations, replacements and equivalent arrangements not described so far, but they are in line with the spirit and scope of the disclosure. In addition, although various embodiments of the disclosure have been described, it should be understood that various aspects of the disclosure may only include some of the described embodiments. Therefore, the present invention is not regarded as being limited by the foregoing description but is only limited by the scope of the appended claims.