Abstract:
A method and apparatus for providing a storm door mortise lock that prevents lockout with a lock body having opposed side plates and a cam in between the side plates, the cam being in operative interaction with a dead bolt assembly. The mortise lock body also may include one or more stops within the deadbolt assembly to limit the rotation of the cam and prevent a lockout situation. A thumb turn button and key cylinder are secured to opposite escutcheon plates. A spindle traverses from the key cylinder through the cam through hole and terminates in the mounting slot of the thumb turn button. Rotation of either the thumb turn button or the key cylinder turns the spindle and actuates the cam that actuates the dead bolt assembly.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is a non-provisional of U.S. Ser. No. 60/515,857 filed on Oct. 30, 2003. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention generally relates to a storm door mortise lock and more specifically to a storm door mortise lock that prevents a lockout situation.  
         [0004]     2. Prior Art  
         [0005]     Storm door mortise locks typically have a dead bolt that is activated by a key cylinder body having a cam. The cam is rotated by either turning a thumb turn button or by use of the correct key in the key cylinder.  
         [0006]     The key cylinder body of the prior art created a danger that a lockout situation could occur. If the cam was over rotated, it would fall out of the notch in the dead bolt assembly and if the dead bolt assembly stopped in a position wherein the cam cannot re-enter the dead bolt. This could leave the dead bolt engaged without a means to disengage it, commonly known as a lockout situation. This would greatly inconvenience the storm door operator and possibly require the disassembly of the storm door. There is therefore a need for a mortise lock that will prevent a lockout situation.  
         [0007]     As seen in  FIG. 4 , one solution of preventing a lockout situation is to provide stops to halt the forward and rearward movement of the cam. While this prevents a lockout situation, there is no biasing effect by the stops against the cam to provide a positive feedback to the user that the deadbolt is moving from an unlocked to locked position and vice versa. There is therefore a need for a spring that influences the cam to provide a positive feedback of movement.  
         [0008]     In addition, the prior art utilized a spring on the inside of the deadbolt. This spring acted upon the cam to bias it toward the stop and out of the plane of the deadbolt. If there was a flaw in the stop such as a crack, an improperly bent stop, or improperly placed stop the spring could push the cam out of the plane of the deadbolt and cause a lockout situation. There is therefore a need for a spring located outside the deadbolt which biases the cam into the plane of the deadbolt thus preventing a lockout situation.  
         [0009]     Still further, the prior art does not use a cam that is interconnected with the dead bolt. This lack of interconnection provides the possibility of a lockout situation as there becomes wear on the stops. In addition, during mass manufacture of the mortise lock it is important to have a rapid evaluation process of interconnectivity that results in preventing a lockout situation. Therefore, there is a need for an interconnection with the cam which prevents a lockout situation and provides for rapid evaluation during the manufacturing process to assure that a lockout situation is prevented.  
         [0010]     There is therefore a need for a storm door with a mortise lock that avoids these and other problems.  
         [0000]     Features of the Present Invention  
         [0011]     A general feature of the present invention is the provision of a storm door mortise lock which overcomes the problems found in the prior art.  
         [0012]     A still further feature of the present invention is the provision of a storm door mortise lock that includes built in stops in the deadbolt to prevent a lockout situation.  
         [0013]     A still further feature of the present invention is the provision of a storm door mortise lock that has a spring which provides positive feedback that the deadbolt is moving from an unlocked to a locked position.  
         [0014]     A still further feature of the present invention is the provision of a storm door mortise lock with a cam body interacting with the spring which provides positive feedback that the deadbolt is moving from an unlocked to a locked position.  
         [0015]     A still further feature of the present invention is the provision of a storm door mortise lock that includes a spring biasing the cam inside the plane of the deadbolt.  
         [0016]     A still further feature of the present invention is the provision of a storm door mortise lock that interconnects the deadbolt with the cam to prevent a lockout situation.  
         [0017]     These, as well as other features and advantages of the present invention will become apparent from the following specification and claims.  
       BRIEF SUMMARY OF THE INVENTION  
       [0018]     The present invention generally comprises an apparatus for providing a storm door mortise lock with lockout prevention. The mortise lock may be either a reversible mortise lock or a solid core mortise lock. The mortise lock includes a lock body having opposed side plates with a dead bolt assembly and a live bolt assembly intermediate the side plates. The bolts slide between retracted and extended positions beyond the edge of the door. A cam is also intermediate the side plates and therefore integral with the mortise lock body. The mortise lock of the present invention also includes a thumb turn button and a key cylinder that are separate from the cam. The thumb turn button and key cylinder are secured to opposite escutcheon plates. A spindle operatively links the key cylinder, cam and thumb turn button. Because these parts are separate, they can be used in storm doors of varying thicknesses by only changing the length of the spindle.  
         [0019]     Further, the mortise lock body of the present invention includes apparatus for prevention of a lockout situation. The apparatus may include built in stops into the deadbolt. These stops prevent the cam from over rotating and resulting in a lockout situation.  
         [0020]     A still further feature of the present invention is the provision of a storm door mortise lock that has a spring which provides positive feedback that the deadbolt is moving from an unlocked to a locked position.  
         [0021]     A still further feature of the present invention is the provision of a storm door mortise lock with the cam body interacting with the spring which provides positive feedback that the deadbolt is moving from an unlocked to a locked position.  
         [0022]     A still further feature of the present invention is the provision of a storm door mortise lock that includes a spring biasing the cam inside the plane of the deadbolt.  
         [0023]     A still further feature of the present invention is the provision of a storm door mortise lock that interconnects the deadbolt with the cam to prevent a lockout situation.  
         [0024]     These features of novelty and various other advantages that characterize the invention are pointed out with particularity in the claims annexed hereto and forming a part hereof. However, for a better understanding of the invention, its advantages, and the objects obtained by its use, reference should be made to the drawings which form a further part hereof, and to the accompanying descriptive matter, in which there is illustrated and described a preferred embodiment of the invention.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0025]     Referring now to the drawings, wherein like reference numerals indicate corresponding structure throughout the several views.  
         [0026]      FIG. 1  is a partial perspective view of an edge of a storm door with the mortise lock of the present invention installed therein.  
         [0027]      FIG. 2  is an exterior top perspective view of a mortise lock according to the principles of the present invention.  
         [0028]      FIG. 3  is an interior top perspective view of the mortise lock shown in  FIG. 2 .  
         [0029]      FIG. 4  is an interior partial exploded perspective view of the mortise lock body of the prior art.  
         [0030]      FIG. 4A  is an exterior side view of the mortise lock body of the prior art with the deadbolt assembly in a locked position.  
         [0031]      FIG. 5  is an interior partial exploded perspective view of the mortise lock body of the present invention.  
         [0032]      FIG. 6  is an interior side view of the mortise lock body of the present invention with the deadbolt assembly in a locked position.  
         [0033]      FIG. 7  is an interior side view of the mortise lock body of the present invention with the deadbolt assembly in an intermediate position.  
         [0034]      FIG. 8  is an interior side view of the mortise lock body of the present invention with the deadbolt assembly in an unlocked position. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0035]     The present invention will be described as it applies to its preferred embodiment. It is not intended that the present invention be limited to the described embodiment. It is intended that the invention cover all modifications and alternatives which may be included within the spirit and scope of the invention.  
         [0036]     Referring now to the drawings, wherein like reference numerals and letters indicate corresponding structure throughout the several views, and referring in particular to  FIGS. 1, 2  and  3 , there is shown a storm door  10  and mortise lock  20  according to the present invention. The mortise lock  20  preferably includes a lock body  22 , exterior escutcheon assembly  24  and interior escutcheon assembly  26 . The exterior escutcheon assembly  24  has a handle  28  to actuate the live bolt assembly  30 . The key cylinder  32 , used to turn the dead bolt assembly  36 , is also part of the exterior escutcheon assembly  24 . The interior escutcheon assembly  26  also includes a handle  29  to actuate the live bolt assembly  30 . A thumb turn button  34  is also provided to turn the dead bolt assembly  36 . The live bolt assembly  30  and the dead bolt assembly  36  are secured to the lock body  22 .  
         [0037]     The key cylinder  32  of the present invention is separate from and does not include the cam  58 . By separating the key cylinder  32  from the cam  58 , the cross-sectional profile of the key cylinder  32  can be minimized and the thickness of the mortise lock body  22  can be minimized and can be altered to allow the lock to be placed in a door body of varying thickness. The cross-sectional profile of the key cylinder  32  is generally circular. A spindle (not shown) is rotatably secured to the key cylinder  32 . The key pin or pins are incorporated within the key cylinder housing. The key cylinder  32  is secured to the exterior escutcheon plate  24 . The thumb turn button  34  is preferably rotatably secured to the interior escutcheon plate  26  by a retaining ring. The thumb turn button  34  includes at least one mounting slot for receiving the spindle.  
         [0038]     The prior art lock body  22  and deadbolt assembly  36  is shown in  FIG. 4  and  FIG. 4A . The lock body  22  includes a cam  58  rotatably secured between two side plates  54  and  55 . The cam  70  includes a through hole  56 . When installed, the spindle passes through the hole  56  and into the thumb turn button  34  such that turning of either the key cylinder  32 , by a corresponding key (not shown), or the thumb turn button  34  will turn the cam  70  and actuate the dead bolt assembly  36 . In the prior art, rotation of the cam  70  is limited by one or more stops  72  formed in or secured to the side plates  54  and  55 . These stops  72  generally prevent the cam  58  from ever losing operative interaction with the notch in the deadbolt assembly  36 . In this way, the prior art prevents lockout situations.  
         [0039]     As is shown in  FIGS. 6-8 , during actuation of the dead bolt assembly  36 , the cam  58  of the present invention will rotate through approximately a  90  degree arc. Rotation of the cam  58  may be limited by one or more stops  38  formed in or secured to the dead bolt assembly  36 . The cam generally includes a cam body  60  and a cam arm  62 . The cam arm  62  extends axially from the cam body  60  and into the dead bolt assembly  36 . When the cam arm  62  is rotated in one direction the dead bolt assembly  36  is extended and the storm door  10  is secured. When the cam arm  62  is rotated in the opposite direction, the dead bolt assembly  36  is retracted and the storm door may be opened. The stops  38  generally prevent the cam arm  62  from ever losing operative interaction from within the dead bolt assembly  36 . This prevents lockout situations.  
         [0040]     Additionally, a spring  50  is mounted between the side plates  54 ,  55  by a spring mount  52 . The spring  50  biases the cam arm  62  to either an unlocked position or a locked position. As seen in  FIG. 7 , the cam  58  goes in a neutral position when it is approximately perpendicular to the deadbolt. This neutral position helps provide a positive feel to the user that the lock is slipping between a locked position as seen in  FIG. 6  to an unlocked position as seen in  FIG. 8 . It is to be understood that numerous spring configurations can be used to influence the cam body  60 . In this embodiment, the spring is a leaf spring attached to the side plate at only one spring end. However, an alternative embodiment may have a spring attached to the side plate at both spring ends.  
         [0041]     Alternatively, the spring  50  may be used to limit the rotation of the cam. As seen in  FIGS. 6, 7  and  8 , the cam body  60  may have a first flat surface  66  and a second flat surface  68 . These two pieces come to a point, as seen in  FIG. 6 . When the deadbolt  36  is in a locked position a first flat surface  66  is approximately parallel with a surface of the leaf spring  50 . As the cam body  60  is rotated to place the lock into an intermediate position, the point between the first flat surface  66  and a second flat surface  68  presses down upon the leaf spring causing the leaf spring to exert a biasing effect upon the cam body  60 . When the cam  58  is rotated through the intermediate position the biasing force from the leaf spring  50  acts upon the cam body  60  until it is flush and parallel with the second flat surface  68  of the cam body  60  as seen in  FIG. 8 . Thus, in this fashion the leaf spring  50  prevents the cam  58  from going past the deadbolt assembly  36  because the spring  50  is pressing against the first flat surface  66  or second flat surface  68  to keep it within the plane of the notch  40 . This further prevents lockout situations.  
         [0042]     In addition, the cam  58  may have a cam finger  64  attached to the cam arm  62 . The cam finger  64  provides a further tool to prevent a lockout situation by enabling the deadbolt assembly  36  and the cam  58  to be interconnected. In this embodiment, the deadbolt assembly  36  has a first notch or first notch portion  40  which permits unobstructed rotation of the cam arm  62 . As shown in  FIGS. 6-7  the first notch  40  is trapezoidal in shape. In addition, the deadbolt assembly  36  may have a second notch or second notch portion  42  within the first notch  40  which interacts with the cam finger  64 . The cam finger  64  can be seen in  FIG. 7A . The second notch  42  preferably has a closed end  44  that prevents the cam finger  64  from slipping out. Thus, the interaction between the cam finger  64  and the closed end  44  creates interconnectivity that prevents a lockout situation.  
         [0043]     The second notch may also have a lock indent  46  that is approximately perpendicular to the cam finger  64  when the deadbolt assembly  36  is in the locked position that prevents closing of the deadbolt assembly  36  by means other than rotation of the key cylinder  32  or thumb turn button  34 . The second notch  42  may also have an unlock indent  48  that is approximately perpendicular to the cam finger  64  when the deadbolt assembly  36  is in the unlocked position that prevents unintentional opening of the deadbolt by means other than the key cylinder  32  or the thumb turn button  34 .  
         [0044]     Finally, it should be noted that there is a vertical side  47  extending from the lock indent  46  and a vertical side  49  extending from the unlock indent  48 . The juncture of the vertical side  47  with the lock indent  46  creates an obstruction such that the cam arm  62  slips over and locks into place in the lock indent  46 . This locking action provides a positive feel to the user that the cam  58  is indeed in the locked position. Similarly, the vertical side  49  juncture with the unlock indent  48  creates an obstruction which when the cam arm  62  passes over provides a positive feel to the user that the deadbolt assembly  36  is in the unlocked position. It is to be understood that this positive feel of moving into the lock and unlock positions may be achieved by other forms than as illustrated in  FIGS. 6-8 .  
         [0045]     A preferred embodiment of the present invention has been set forth above. It should be understood by one of ordinary skill in the art that modifications may be made in detail, especially in matters of shape, size and arrangement of parts. Such modifications are deemed to be within the scope of the present invention which is to be limited only by the broad general meaning of the terms in which the appended claims are expressed.