Abstract:
A multi-point sliding door latch intended to fit within standard sized opening in the stile of a sliding door. Preferably the latch has at least two hooks oriented in opposite directions that slide in a generally linear manner between an unlatched and latched position in response to rotation of a pair of actuators located within the latch housing. Preferably, the latch includes reinforcement blocks defining cavities with a portion of the hooks extending into the cavities when the hooks are in the latched position.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to multi-point door latches and more particularly to a multi-point door latch particularly suitable for use with sliding doors. 
     There remains a need for sliding door locks with increased strength and multiple connection points between the sliding door and the corresponding door jamb. The increased strength and multiple connection points reduce the chance of a successful forced entry and allow the lock to be used with relatively heavy doors and in other applications in which the lock may be placed under relatively high tension. 
     A standard sliding door installation, such as a sliding glass door, typically includes a latch or lock mounted in the face of the stile of the sliding door. Most such locks have a single hook or latching element that interacts with a keeper plate on the corresponding door jamb. A lock with two hooks or latches provides at least two advantages over a lock with a single hook. First, the lock with two connection points can be constructed to withstand higher forces. Second, if the two hooks are oriented in opposite directions, it precludes the possibility of tilting or lifting the door to disengage the hooks from the keeper plate and thus defeat the lock. Many multi-point sliding door locks are complex, relatively expensive and require substantial modification of the stile of the sliding door during installation of the lock. Thus, there remains a need for a simple, strong, relatively inexpensive and easy to install multi-point sliding door lock. 
     Most sliding door locks employ a rotating or pivoting hook as the attachment point between the sliding door and the keeper plate. The hook rotates between an unlocked position in which it is within the housing of the door lock and a locked position in which it rotates out of the housing to engage the keeper plate. Locks based on a sliding engagement mechanism may be constructed to be stronger than locks based on a rotating mechanism. It is believed that a multiple point door lock based on a sliding engagement mechanism and adapted to fit into the standard opening of a sliding door stile are not known in the art. 
     SUMMARY OF THE INVENTION 
     The present invention provides a lock particularly adapted for increased security against forced entry and heavy doors. The lock provides two points of attachment between the lock and the keeper plate. The attachment means slide rather than rotate allowing for very strong reinforcement of the attachment means which, in turn, allows for a very strong attachment between the lock and the keeper plate. Such strength minimizes the chances of a forced entry accomplished through failure of the lock. Preferably, the attachment means are hooks oriented in opposite directions. Such orientation eliminates the possibility of gaining entry by lifting the hooks out of the opening in the keeper plate by tilting or lifting the door. 
     Preferably, the lock is sized to fit into standard size openings for receiving locks in the stile of a sliding door. The latch may also be provided with a mechanism to prevent the latch from being placed into the locked position unless the sliding door is closed against the opposing jamb. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of a typical patio door installation; 
         FIG. 2  is a front view of one embodiment of the invention; 
         FIG. 3  is a side view of one embodiment of the invention; 
         FIG. 4  is a bottom view of one embodiment of the invention; 
         FIG. 5  is a side view of the outer casing of one embodiment of the invention; 
         FIG. 6  is a side view of a hook of one embodiment of the invention; 
         FIG. 7  is an end view of a hook of one embodiment of the invention; 
         FIG. 8  is a plan view of two actuators of one embodiment of the invention; 
         FIG. 9  is an end view of an actuator of one embodiment of the invention; 
         FIG. 10  is an exploded perspective view of one embodiment of the invention; 
         FIG. 11  is a perspective view showing a typical installation of one embodiment of the invention; 
         FIG. 12  is a side cut-away view of a portion of one embodiment of the invention showing the latch in an unlocked position with the hook somewhat extended away from the surface of the latch; 
         FIG. 13  is a side cut-away view of a portion of one embodiment of the invention showing the latch in a locked position with the hook somewhat extended away from the surface of the latch; 
         FIG. 14  is a side cut-away view of a portion of one embodiment of the invention showing the latch in an unlocked position with the hook somewhat retracted into the latch; and 
         FIG. 15  is a side cut-away view of a portion of one embodiment of the invention showing the latch in a locked position with the hook somewhat retracted into the latch. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The following description relates only to a preferred embodiment of the invention. The specific features described below do not limit the scope of the invention. 
       FIG. 1  shows a typical arrangement for a sliding patio door. Doors  10  and  12  are fixed within an opening in wall  14 . Door  16  slides between the open position shown and a closed position in which stile  18  abuts jamb  20 . In the closed position, latch  22  within stile  18  contacts keeper plate  24  on jamb  20 . Preferably, latch  22  is sized to fit within a standard size opening in stile  18 . 
       FIG. 11  shows a typical arrangement for mounting latch  22  within an opening of stile  18 . Keeper plate  24  is mounted opposite latch  22  on jamb  20  ( FIG. 1 ). Screws  50  pass through holes  40  and secure latch  22  within the opening in the face of stile  18 . Door handle  52  is secured to the side of stile  18  by fasteners  54 . Fasteners  54  may be screws, bolts or the like and may pass through the entire stile  18  via holes  56  in handle  52 , holes  58  in stile  18  and holes  60  in outer casing  26  of latch  22 . Thumb lever  62  comprises a lever portion  64  and a tail portion  66 . Tail portion  66  passes through hole  68  in handle  52  and hole  70  in stile  18  to engage receiver  72 A or  72 B of actuator  74 A or  74 B ( FIG. 8 ). 
     As shown in  FIGS. 2 through 5 , the latch comprises an outer casing  26 , a faceplate  28 , a centering peg  30 , an upper hook  32 , a lower hook  34  and a safety plunger  36 . The faceplate  28  is held to the outer casing  26  by screws  38 . Faceplate  28  is provided with holes  40  for attaching the latch to stile  18 . As explained below in further detail, screws  42  allow the adjustment of the extent to which hooks  32  and  34  protrude from the surface of faceplate  28 . 
     The description of hooks  32  and  34  will be made with particular reference to hook  32 , however, hooks  32  and  34  are essentially identical except that they are mirror images of each other. As shown in  FIGS. 7 and 10 , hook  32  has a laminate construction. With reference to  FIG. 6 , hook  32  has hook portion  32   a , sliding arm portion  32   b , body portion  32   c  and receiver portion  32   d . Sliding arm portion  32   b  defines indentations  44  and  46  which will be explained further below. Body portion  32   c  defines aperture  48  which also will be explained further below. 
       FIGS. 12 and 13  show how the various components of the latch interact to move hook  32  between an unlatched state ( FIG. 12 ) and a latched state ( FIG. 13 ). As shown,  FIGS. 12 and 13  show primarily the upper portion of latch  22 , however, the following descriptions of the upper portion apply equally to the identical components in the lower portion of lock  22 . Beginning with the unlatched state shown in  FIG. 12 , a user rotates tail portion  66  via thumb lever  64  ( FIG. 11 ). Tail portion  66  is engaged in receiver  72   a  or  72   b  of actuator  74   a  or  74   b . Peg  76  is engaged with actuator  74   b  and travels in raceway  78  of outer casing  26 . Peg  76  is also contained within receiver portion  32   d  ( FIG. 6 ) of hook  32 . As shown in  FIGS. 12 and 13 , as actuator  74   b  rotates, peg  76  travels along raceway  78  and exerts lateral force against receiver portion  32   d  of hook  32  causing hook  32  to slide from the open position shown in  FIG. 12  to the latched position shown in  FIG. 13  in a generally linear motion that is generally parallel with faceplate  28 . During such latching, sliding arm portion  32   b  of hook  32  slides laterally with respect to reinforcement block  80 . Peg  92  within raceway  48  also serves to hold hook  32  in the correct position. Nub  102  and spring  104  act against sliding arm portion  32   b  of hook  32  and bias it upwards against reinforcement block  80 . In the unlatched position the tip of nub  102  rests within indentation  44  and in the latched position the tip of nub  102  rests within indentation  46 . 
     In the fully latched position, shown in  FIG. 13 , sliding arm portion  32   b  of hook  32  extends within cavity  82  of reinforcement block  80 . Such an arrangement provides a much stronger link between the latch  22  and keeper plate  24  than is typical with latches with rotary hooks. The prototype of one embodiment of the invention is capable of withstanding more than 1,500 lbs/foot of force. 
     Reinforcement block  80  is held in position by screw  90 , peg  94  within raceway  96  and tab  98  ( FIG. 10 ) within raceway  100 . Screw  90  in combination with reinforcement block  80  provide a means for adjusting the extent to which hooks  32  and  34  protrude from the surface of latch  22  to accommodate different thicknesses of keeper plate  24 . By rotation of screw  90 , reinforcement block  80  is moved closer (as shown in  FIGS. 12 and 13 ) or further away (as shown in  FIGS. 14 and 15 ) from the surface of latch  22  which, in turn, extends or retracts hook  32  with respect to the surface of latch  22 . 
     As shown in  FIG. 8 , actuators  74   a  and  74   b  are provided with gearing  102   a  and  102   b  that act together. Thus, rotating either actuator  74   a  or actuator  74   b  results in the rotation of the other actuator as well which, in turn, causes the associated hook,  32  or  34  to move to the latched or unlatched position as explained above. 
     Safety plunger  36  is designed to prevent an operator of the latch from locking the latch unless the door  16  ( FIG. 1 ) is closed. When door  16  is open, spring  84  biases annular flange  86  against body portion  32   c  of hook  32 . Flange  86  and tab  88  of hook  32  prevent hook  32  from being moved laterally to a locked position. When door  16  is closed, safety plunger  36  is depressed by jam  20  which in turn depresses flange  86  enough to allow tab  88  to pass thus allowing hook  32  to be moved laterally. In this manner, safety plunger  36  prevents an operator of the latch from operating the latch, and therefore believing door  16  to be locked, without engaging hooks  32  and  34  with keeper plate  24 . 
     The foregoing description is of a preferred embodiment of the invention. Various changes, modifications or substitutions may be made in the disclosed embodiment without departing from the scope or spirit of the invention.