Abstract:
A multipoint mortise lock mechanism for a swinging door, including a central cassette assembly operably coupled to an upper remote locking point assembly and a lower remote locking point assembly by a remote locking linkage. The central cassette assembly includes a housing, a deadbolt mechanism, a latchbolt mechanism, a remote locking point mechanism and an anti-slam mechanism. The anti-slam mechanism includes an anti-slam plunger that when in an extended position engages the remote locking linkage via a boss and a slot and thereby inhibits movement of the remote locking linkage whereby deployment of the remote locking point assemblies is prevented. The deadbolt mechanism includes a deadbolt extendible from the central cassette that is independently operable from the remote locking point mechanism. The deadbolt mechanism further includes an anti-back drive mechanism.

Description:
CLAIM TO PRIORITY 
     This application is a continuation of application Ser. No. 12/827,833, filed Jun. 30, 2010, now U.S. Pat. No. 8,550,506, which claims the benefit of U.S. Provisional Application No. 61/221,975 entitled “Multi-point Mortise Lock Mechanism for Swinging Door” filed Jun. 30, 2009, U.S. Provisional Application 61/248,673 entitled “Door Latch with Integrated Latch Lubrication Strip” filed Oct. 5, 2009 and U.S. Provisional Application 61/245,560 entitled “Multi-point Mortise Lock Mechanism for Swinging Door” filed Sep. 24, 2009, the entire contents of all of the above applications being incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to lock mechanisms for doors, and more specifically, to multi-point lock mechanisms for swinging doors. 
     BACKGROUND OF THE INVENTION 
     While multi-point lock mechanisms for swinging doors are known, devices developed to date have drawbacks and have not entirely fulfilled the needs of the industry. 
     In the field of swinging door latching devices it is common to have a wedge shaped latchbolt that extends from a cassette or cylindrical cartridge containing an actuating mechanism. The latchbolt is generally spring-loaded and biased toward the extended position, and is retracted against the bias of the spring by operation of a lever or knob. The latchbolt typically contacts a strike plate in a door frame in such a way as to press the spring loaded latchbolt into the cassette until the latchbolt reaches a hole in the strikeplate. The spring loaded latchbolt then engages in the strikeplate hole and secures the door panel to the door frame. 
     Prior latchbolts are generally made of metal and have a tendency to scratch and mar the corresponding strikeplates, many of which are decorative plated, causing noisy and rough operation when closing the door panel in the door frame, and an unsightly appearance to the strikeplate. Accordingly, what is needed in the industry is a latch mechanism with a latch bolt that does not cause scratching and marring of the strikeplate. 
     SUMMARY OF THE INVENTION 
     Embodiments of the invention address the needs of the industry by providing all or certain of these features in a multi-point lock assembly for a swinging door: 
     In one embodiment the invention includes an Anti-slam mechanism including a detent and rotatable paddle. The detent and rotatable paddle make the anti-slam mechanism bidirectional. 
     In another embodiment of the invention, the Anti-slam mechanism includes an independent tie in to the remote bolts via a boss and a slot. This permits the remote bolts to be operated independent of whether the deadbolt is locked or not. 
     In another embodiment of the invention, the Anti-slam mechanism includes an independent tie in to dead bolt via linkage. This permits the deadbolt to be operated whether the remote bolts are locked or not. 
     Another aspect of the invention permits the Dead bolt and remote bolts to operate independently in extension and retraction. 
     The invention may include a dead bolt driver that extends the dead bolt and locks out the handle of the lock mechanism with a stop bar. 
     In another aspect of the invention, both a spring loaded pawl and a dead bolt driver secure the deadbolt in the locked position so that there are two support points to prevent back drive of dead bolt. 
     The invention further includes a method of lifting spring loaded pawl to bypass support point when retracting dead bolt. 
     In another embodiment the invention includes a flat spring that provides for detent feel of dead bolt driver and retention of dead bolt in position. 
     In another embodiment the invention includes a torsion spring for the upper operation bar to hold it in position. 
     In another aspect of the invention a compression spring is used to return the handle to a neutral position and to control handle droop so that the handle returns reliably to the neutral position. 
     In another embodiment the invention includes a reversibly handed anti-slam plunger that changes handedness via a rotating paddle. 
     In another aspect of the invention, the invention includes a rotating latch bolt for interchangeable handing and retaining of the latch bolt at the functional position. 
     The invention may further include reversed upper and lower drive bars so that gravity assists in balancing the upper and lower tie bars and remote bolts. 
     In another embodiment, the present invention addresses the need of the industry for a latch mechanism with a latchbolt that does not cause scratching and marring of the strikeplate. According to embodiments of the invention, a lubrication strip made of a lubricious, yet durable material is inset into the latchbolt. The lubrication strip is disposed so as to contact and slide along the strikeplate when the door is closed, thereby preventing contact between the metal portions of the latchbolt with the strikeplate, and as a result, inhibiting scratching and marring of the strikeplate. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention may be more completely understood in consideration of the following detailed description of various embodiments of the invention in connection with the following drawings, in which: 
         FIG. 1  is a perspective view of a multi-point lock assembly according to an embodiment of the invention; 
         FIG. 1A  is a perspective view of a swinging door with the multi-point lock assembly of  FIG. 1  therein; 
         FIG. 2  is another perspective view of a multi-point lock assembly of  FIG. 1 ; 
         FIG. 3  is a partially exploded view of the lock assembly of  FIG. 1 ; 
         FIG. 4  is a side elevation view of the central cassette of the lock assembly of  FIG. 1  with the anti-slam plunger extended; 
         FIG. 5  is a side elevation view of the central cassette of the lock assembly of  FIG. 1  with the anti-slam plunger depressed; 
         FIG. 6  is a partially exploded perspective view of the central cassette of the lock assembly of  FIG. 1 ; 
         FIG. 7  is a fragmentary side elevation view of the lock assembly of  FIG. 1  in a first operational disposition; 
         FIG. 8  is a fragmentary side elevation view of the lock assembly of  FIG. 1  in a second operational disposition; 
         FIG. 9  is a fragmentary side elevation view of the lock assembly of  FIG. 1  in a third operational disposition; 
         FIG. 10  is a fragmentary side elevation view of the lock assembly of  FIG. 1  in a fourth operational disposition; 
         FIG. 11  is a side elevation view of the central cassette of the lock assembly of  FIG. 1  with the dead bolt in a retracted position; 
         FIG. 12  is a side elevation view of the central cassette of the lock assembly of  FIG. 1  with the dead bolt in an extended position; 
         FIG. 13  is a perspective view of the central cassette of the lock assembly of  FIG. 1  with the latch bolt in a first rotational position; 
         FIG. 14  is a perspective view of the central cassette of the lock assembly of  FIG. 1  with the latch bolt in a second rotational position; 
         FIG. 15  is a perspective view of the central cassette of the lock assembly of  FIG. 1  with the latch bolt in a third rotational position; 
         FIG. 16  is a perspective view of the central cassette of the lock assembly of  FIG. 1 ; 
         FIG. 17  is a perspective view of a multi-point lock assembly according to another embodiment of the invention; 
         FIG. 18  is another perspective view of the multi-point lock assembly of  FIG. 17 ; 
         FIG. 19  is a partially exploded view of the lock assembly of  FIG. 17 ; 
         FIG. 20  is a side elevation view of the central cassette of the lock assembly of  FIG. 17  with the anti-slam plunger extended; 
         FIG. 21  is a side elevation view of the central cassette of the lock assembly of  FIG. 17  with the anti-slam plunger depressed; 
         FIG. 22  is a partially exploded perspective view of the central cassette of the lock assembly of  FIG. 17 ; 
         FIG. 23  is a fragmentary side elevation view of the lock assembly of  FIG. 17  in a first operational disposition; 
         FIG. 24  is a fragmentary side elevation view of the lock assembly of  FIG. 17  in a second operational disposition; 
         FIG. 25  is a fragmentary side elevation view of the lock assembly of  FIG. 17  in a third operational disposition; 
         FIG. 26  is a fragmentary side elevation view of the lock assembly of  FIG. 17  in a fourth operational disposition; 
         FIG. 27  is a vertical sectional view of the central cassette of the lock assembly of  FIG. 17  with the handle in a neutral position; 
         FIG. 28  is a vertical sectional view of the central cassette of the lock assembly of  FIG. 17  with the handle in a downward position; 
         FIG. 29  is a vertical sectional view of the central cassette of the lock assembly of  FIG. 17  with the handle in a upward position; 
         FIG. 30  is a side elevation view of the central cassette of the lock assembly of  FIG. 17  with the dead bolt in a retracted position; 
         FIG. 31  is a side elevation view of the central cassette of the lock assembly of  FIG. 17  with the dead bolt in an extended position; 
         FIG. 32  is a perspective view of the central cassette of the lock assembly of  FIG. 17  with the latch bolt in a first rotational position; 
         FIG. 33  is a perspective view of the central cassette of the lock assembly of  FIG. 17  with the latch bolt in a second rotational position; 
         FIG. 34  is a perspective view of the central cassette of the lock assembly of  FIG. 17  with the latch bolt in a third rotational position; 
         FIG. 35  is a sectional view of the lock cassette of  FIG. 17  taken through section A-A with the anti-slam plunger configured in two different positions according to an embodiment of the invention; 
         FIG. 36  is a perspective view of the central cassette of the lock assembly of  FIG. 17 . 
         FIG. 37  is a perspective view of a multi-point lock assembly according to another embodiment of the invention; 
         FIG. 38  is another perspective view of the multi-point lock assembly of  FIG. 37 ; 
         FIG. 39  is a partially exploded view of the lock assembly of  FIG. 37 ; 
         FIG. 40  is a side elevation view of the central cassette of the lock assembly of  FIG. 37  with the anti-slam plunger extended; 
         FIG. 41  is a side elevation view of the central cassette of the lock assembly of  FIG. 37  with the anti-slam plunger depressed; 
         FIG. 42  is a partially exploded perspective view of the central cassette of the lock assembly of  FIG. 37 ; 
         FIG. 43  is a fragmentary side elevation view of the lock assembly of  FIG. 37  in a first operational disposition; 
         FIG. 44  is a fragmentary side elevation view of the lock assembly of  FIG. 37  in a second operational disposition; 
         FIG. 45  is a fragmentary side elevation view of the lock assembly of  FIG. 37  in a third operational disposition; 
         FIG. 46  is a fragmentary side elevation view of the lock assembly of  FIG. 37  in a fourth operational disposition; 
         FIG. 47  is a vertical sectional view of the central cassette of the lock assembly of  FIG. 37  with the handle in a neutral position; 
         FIG. 48  is a vertical sectional view of the central cassette of the lock assembly of  FIG. 37  with the handle in a downward position; 
         FIG. 49  is a vertical sectional view of the central cassette of the lock assembly of  FIG. 37  with the handle in a upward position; 
         FIG. 50  is a side elevation view of the central cassette of the lock assembly of  FIG. 37  with the dead bolt in a retracted position; 
         FIG. 51  is a side elevation view of the central cassette of the lock assembly of  FIG. 37  with the dead bolt in an extended position; 
         FIG. 52  is a perspective view of the central cassette of the lock assembly of  FIG. 37  with the latch bolt in a first rotational position; 
         FIG. 53  is a perspective view of the central cassette of the lock assembly of  FIG. 37  with the latch bolt in a second rotational position; 
         FIG. 54  is a perspective view of the central cassette of the lock assembly of  FIG. 37  with the latch bolt in a third rotational position; 
         FIG. 55  is a sectional view of the lock cassette of  FIG. 37  taken through section A-A with the anti-slam plunger configured in two different positions according to an embodiment of the invention; 
         FIG. 56  is a partial side elevation view of the central cassette of the lock assembly of  FIG. 37  with the dead bolt in an extended position and an anti-backdrive bolt and locking pin in a first operational position; 
         FIG. 57  is a partial side elevation view of the central cassette of the lock assembly of  FIG. 37  with the dead bolt in an extended position and an anti-backdrive bolt and locking pin in a second operational position; 
         FIG. 58  is a partial side elevation view of the central cassette of the lock assembly of  FIG. 37  with the dead bolt in an extended position and an anti-backdrive bolt and locking pin in a third operational position; 
         FIG. 59  is a perspective view of the central cassette of the lock assembly of  FIG. 37 . 
         FIG. 60  is a perspective view of a latch cassette with latchbolt according to an embodiment of the invention; 
         FIG. 61  is a top plan view of a latchbolt according to an embodiment of the invention; 
         FIG. 62  is a front view of the latchbolt of  FIG. 61 ; 
         FIG. 63  is a bottom plan view of the latchbolt of  FIG. 61 ; 
         FIG. 64  is a left elevation of the latchbolt of  FIG. 61 ; and 
         FIG. 65  is a perspective view of a latchbolt according to an embodiment of the invention. 
     
    
    
     While the present invention is amendable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the present invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present invention. 
     DETAILED DESCRIPTION 
     Lock assembly  100  according to an embodiment of the invention is depicted in  FIGS. 1-16 . In  FIG. 1A , lock assembly  100  is depicted as mounted in the edge of a swinging door  102 . As depicted in  FIG. 1 , lock assembly  100  generally includes latch bolt  201 , dead bolt  202 , and anti-slam plunger  203  located in central cassette  204  with two or more remote locking points  205 . Remote locking points  205  can be permanently attached to the center cassette or attachable as a separate module as depicted in  FIG. 2 . 
     Locks at the remote locking points  205  may be tungs, hooks, bolts, etc. that extend horizontally into a vertical door frame and/or may be shoot bolts that extend vertically into a horizontal door frame header and threshold. 
     As depicted in  FIG. 3 , remote locking points  205  may also generally include hook  206  as is commonly known in the art. Further general details of multi-point locking systems are disclosed in PCT International Publication No. WO 2008/153707 hereby fully incorporated herein by reference. 
     As depicted in  FIGS. 1A and 4 , when swinging door  102  is in the open position, swung away from door frame  104 , anti-slam plunger  203  protrudes from central cassette  204 . Anti-slam plunger  203  is biased toward the extended position by compression spring  207 . Boss  208  of anti-slam plunger  203 , depicted in  FIG. 6 , engages with slot  209  in upper operation bar  210 , thereby blocking translational movement of operation bar  210 . 
     As depicted in  FIG. 3 , remote locking points  205  are coupled to operation bars  210  and  233  with tie bars  211  and the remote locking points  205  are thereby prevented from being extended when anti-slam plunger  203  is extended. 
     As depicted in  FIG. 4 , pawl  213  is rotatable about boss  282 . Side  212  of anti-slam plunger  203  engages end  219  of pawl  213  in a rotated position, engaging with slot  214  in stop bolt  215 , blocking the stop bolt  215  from translational movement. Stop bolt  215  defines rack  216  that engages gear teeth  217  defined in dead bolt driver  218 , thus blocking dead bolt  202  from being extended. 
     As depicted in  FIG. 5 , when door  102  is closed, anti-slam plunger  203  contacts a strike in door frame  104 , depressing anti-slam plunger  203 . Boss  208  of anti-slam plunger  203  clears slot  209  in upper operation bar  210  enabling translational movement of upper operation bar  210  and extension of remote locking points  205 . Clearance slot  220  in side  212  of anti-slam plunger  203  registers with end  219  of pawl  213  at the same time that anti-slam plunger  203  contacts opposite end  221  of pawl  213  and end  219  rotates out of slot  214  in stop bolt  215  and into clearance slot  220  of anti-slam plunger  203 . Stop bolt  215  is thereby freed for translational movement, enabling rotational movement of dead bolt driver  218  to extend dead bolt  202 . 
     The effect is that when door  102  is open, remote locking points  205  and dead bolt  202  are blocked from extending, thus preventing remote locking points  205  and dead bolt  202  from “slamming” and damaging the door frame as the door is closed. Remote locking points  205  and dead bolt  202  are free to extend when the door is closed. Compression spring  222  loaded latch bolt  201  has an angled ramp surface  223  that causes it to depress as it contacts a strike in door frame  104 , and extends once it reaches a slot in the strike (not shown) latching the door, similar to latch bolts common in the field. 
     As depicted in  FIGS. 7 and 8 , remote locking points  205  are extended by a rotational input from door handle  224  that is keyed to central spindle  225 . Spindle  225  protrudes and is keyed to crank  227  in central cassette  204 . Crank  227  has upper arm  228  that rotates downward contacting captured pin  229  in upper operation bar  210  and urging upper operation bar  210  in a downward direction. Upper operation bar  210  defines rack  230  at the lower end that drives pinion  231  rotationally, in turn driving rack  232  defined in lower operation bar  233  in an upward direction. Operation bars  210  and  233  are coupled to tie bars  211  by toothed racks  234 . Tie bars  211  are coupled to and drive remote locking points  205  to the extended position into strikes located on the door vertical frame or, in the case of shoot bolts (not shown), drive the bolts vertically into strikes located on the door frame header or threshold. As door handle  224  is released, torsion spring  235  holds operation bars  210  and  233  in the extended position, while crank torsion spring  236  has leg  237  that pushes against crank tab  239  and leg  238  bearing against standoff  242  that drives the crank  227  to the neutral position. It is important to note that remote locking points  205  can be extended regardless of whether dead bolt  202  is extended or retracted. 
     As depicted in  FIGS. 9 and 10 , remote locking points  205  are retracted by a rotational input from door handle  224  keyed to central spindle  225  which protrudes and is keyed to crank  227  in central cassette  204 . Crank  227  has lower arm  244  that rotates upward and contacts captured pin  229  in upper operation bar  210  and pushes upper operation bar  210  in an upward direction. Rack  230  of upper operation bar  210  drives pinion  231  rotationally, thereby driving rack  232  in lower operation bar  233  in a downward direction. Operation bars  210  and  233  drive tie bars  211  via toothed racks  234 . Tie bars  211  drive remote locking points  205  and/or shoot bolts to the retracted position, disengaging remote locking points  205  from strikes in the door frame  104 . Crank  227  defines lobe  245  on upper arm  228  that contacts a corresponding lobe  246  on latch bolt base  247 , thereby retracting latch bolt  201  against the bias of compression spring  222 . When retracted, latch bolt  201  is disengaged from the strikes in door frame  104 . Alternatively, with remote locking points  205  in the retracted position, door handle  224  can be rotated downward and latch bolt  201  retracted. 
     As all bolts  201 ,  202 ,  205 , are retracted, door  102  may now be rotated to the open position. As anti-slam plunger  203  moves away from door frame  104 , it is released to the extended position. Boss  208  shifts into slot  209  on upper operation bar  210 , blocking movement of upper operation bar  210  and effectively blocking extension of remote locking points  205 . Simultaneously as depicted in  FIG. 5 , wall  249  inside slot  220  of anti-slam plunger  203  bears against ramped surface  250  on pawl  213 , causing end  219  of pawl  213  to rotate out of slot  220  and into engagement in slot  214  on stop bolt  215 , blocking stop bolt  215  from shifting, and thus blocking dead bolt driver  218  from driving dead bolt  202 . As depicted in  FIGS. 9 and 10 , when door handle  224  is released, torsion spring  235  retains operation bars  210  and  233  in the retracted position. Crank torsion spring  236  presents leg  238  that pushes against crank tab  240  and leg  237 , bearing against standoff  241  and driving crank  227  to the neutral position. Simultaneously, lobe  245  in upper arm  228  of crank  227  rotates away from latch bolt lobe  246 , enabling the compression spring to extend latch bolt  201 . 
     Bolt  202  is extended by a rotation of a thumb turn or thumb turn/lock cylinder common in the field (not shown). A spindle (common in the field) protrudes from the thumb turn into slot  248  in dead bolt driver  218 . As dead bolt driver  218  rotates, boss  251  on opposite end  255  engages cam slot  252 , driving dead bolt  202  in a horizontal translational motion. Cam slot  252  presents surface  253  such that, as dead bolt  202  reaches its maximum extension, boss  251  on dead bolt driver  218  reaches a toggle position in the cam slot  252 , blocking dead bolt  202  from being back driven by a force applied to end surface  254  of dead bolt  202  parallel to dead bolt translational motion. Simultaneously, as dead bolt driver  218  rotates, opposite end  255  of dead bolt driver  218  urges lobe  256  on lifter  257  in a rotational motion such that upper lobe  258  contacts and lifts spring loaded pawl  259 . As dead bolt  202  reaches full extension, lifter  257  is enabled to rotate down, dropping pawl  259  below notch  260  in dead bolt  202  to thereby assist in blocking dead bolt  202  from being back driven. Dead bolt driver  218  defines gear teeth  217  that engage rack  216  in stop bolt  215 . As dead bolt driver  218  rotates, it drives stop bolt  215  in a horizontal direction, and engaging protrusion  280  in slot  261  in stop bar  262 , thereby blocking downward translational movement of stop bar  262 . Rack  263  in stop bar  262  engages gear teeth  264  in crank  227 , blocking downward rotation of crank  227  and thus blocking retraction of remote locking points  205  if they are already extended. Slot  261  in stop bar  262  has clearance  265  below stop bolt  215  that enables upward translational movement of stop bar  262 , upward rotation of crank  227 , and extension of remote locking points  205  while dead bolt  202  is extended. Dead bolt  202  can be extended or retracted regardless of whether remote locking points  205  are extended or retracted. Remote locking points  205  cannot be retracted if dead bolt  202  is extended. 
     Dead bolt  202  is retracted by a rotation of a thumb turn or thumb turn/lock cylinder (not shown). A spindle as is common in the field protrudes from the thumb turn into slot  248  in dead bolt driver  218 . As dead bolt driver  218  rotates, opposite end  255  of dead bolt driver  218  contacts lobe  256  on lifter  257 . Lifter  257  is thereby rotated such that upper lobe  258  lifts spring loaded pawl  259  clear of notch  260  on dead bolt  202 . Boss  251  on the end of dead bolt driver  218  then rotates to surface  266  in cam slot  252  of dead bolt  202  and driving dead bolt  202  to the retracted position. Simultaneously, gear teeth  217  of dead bolt driver  218  are engaged with rack  216  on stop bolt  215 . Stop bolt  15  is driven in a horizontal direction, disengaging protrusion  280  from slot  261  in stop bar  262  and freeing stop bar  262  to move vertically downward and enabling rotation of crank  227 . 
     It is common in the field to have left hand opening doors and right hand opening doors. It is advantageous for latch bolt  201  and anti-slam plunger  203  to accommodate opposing rotations of the doors either by offering separate hardware with opposing ramps, by offering interchangeability, or by making them non-handed. As depicted in  FIG. 13 , this is accomplished for anti-slam plunger  203  of embodiments of the invention by incorporating a symmetrical roller  267 , thus making it non-handed and functional from either direction. 
     As depicted in  FIGS. 13, 14, and 15 , latch bolt  201  of embodiments of the invention is made interchangeable by restricting the translational movement of the latch bolt  201  with torsion spring  268 . Torsion spring  268  has leg  269  extending from central coil  270 . Leg  269  engages into notch  271  in bent up wall  272  of cassette housing  243 . Central coil  270  wraps around standoff  273  secured to the housing  243 , and in the free unloaded position additional leg  274  extends perpendicular to the direction of travel of latch bolt  201 . Additional leg  274  of torsion spring  268  limits latch bolt  201  at the extended position so as not to extend beyond the opening  275  in cassette housing  243 . Torsion spring  268  will apply a resistance force to latch bolt base  247  as latch bolt end  276  is pulled from and clears housing opening  275 . Latch bolt end  276  is then rotated  180  degrees, positioning ramp  223  on latch bolt end  276  for the opposite handed door. Torsion spring  268  is allowed to return to its at rest position, pulling latch bolt end  276  back into housing opening  275 . Housing wall  278  and cover wall  279  hold latch bolt end  276  in rotational position. 
     A lock  300  according to a second embodiment is depicted in  FIGS. 17-36 and 1A . Lock  300  may be mounted in the edge of a swinging door  102  as depicted in  FIG. 1A . Looking first to  FIG. 17 , latch bolt  301 , dead bolt  302 , and anti-slam plunger  303  are disposed in central cassette  304  with two or more remote locking points  305 . Remote locking points  305  can be permanently attached to center cassette  304  or attachable as a separate module as depicted in  FIG. 18 . Locks at remote locking points  305  may be tungs, hooks, bolts, or any other suitable element that extend horizontally into a vertical door frame and may include shoot bolts (not shown) that extend vertically into a horizontal door frame header and threshold. For exemplary purposes, hook  81  is depicted in  FIG. 19 , but any of the above elements may be added or substituted. 
     As depicted in  FIG. 20 , when door  102  is in the open position, swung away from the door frame, anti-slam plunger  303  protrudes from central cassette  304 . Anti-slam plunger  303  is held in an extended position by compression spring  307 . Boss  308 , shown in  FIG. 22 , on anti-slam plunger  303  keys into slot  309  in upper operation bar  310  blocking translational movement. Upper operation bar  310  has rack  330  that engages pinion  331 , which engages rack  332  in lower operation bar  333 . As in  FIG. 19 , remote locking points  305  are coupled to operation bars  310  and  333  by tie bars  311 , and remote locking points  305  are prevented from being extended. As depicted in  FIG. 20 , blocker link  313  rotates about pin  382 . End  312  of blocker link  313  is held in position by slot  315  in the side of anti-slam plunger  303  such that other end  314  of blocker link  313  is positioned with respect to lobe  316  of dead bolt driver  318 , thereby preventing dead bolt driver  318  from rotating and extending dead bolt  302 . 
     When door  102  is closed anti-slam plunger  303  contacts a strike in the door frame (not shown) which depresses anti-slam plunger  303  as depicted in  FIG. 21 . As depicted in FIG.  22 , boss  308  of anti-slam plunger  303  clears slot  309  in upper operation bar  310  enabling translational movement of upper operation bar  310  which may in turn drive translation of lower operation bar  333  through racks  330 ,  332 , and pinion  331 , thereby resulting in extension of remote locking points  305 . As depicted in  FIG. 21 , slot  315  in anti-slam plunger  303  positions blocker link end  312  so that blocker link  313  rotates about pin  382  and rotates other blocker link end  314  clear of lobe  316  of dead bolt driver  318 , thereby enabling rotational movement of dead bolt driver  318  to extend dead bolt  302 . 
     The overall effect is that when door  102  is open, remote locking points  305  and dead bolt  302  are blocked from extending, thus preventing remote locking points  305  and dead bolt  302  from “slamming” into and damaging the door frame as the door is closed. Remote locking points  305  and dead bolt  302  are freed to extend, however, when the door is closed. Compression spring  322  loaded latch bolt  301  has angled ramp surface  323  that causes it to depress as it contacts a strike in the door frame, and extend once it reaches a slot in the strike (not shown) thereby latching the door, similar to other latch bolts common in the field. 
     As depicted in  FIGS. 23, 24 and 29 , remote locking points  305  and/or shoot bolts (not shown) are extended by an upward rotational input from door handle  324 , which is keyed to central spindle  325 . Spindle  325  protrudes from central cassette  304  and is keyed to crank  327 . Crank  327  has upper arm  328  that rotates downward, contacting captured pin  329  in upper operation bar  310  and pushing upper operation bar  310  in a downward direction. Upper operation bar  310  defines rack  330  at its lower end that drives pinion  331  rotationally, which in turn drives rack  332  of lower operation bar  333  in an upward direction. Operation bars  310  and  333  are connected to tie bars  311  by toothed racks  334 . Tie bars  311  are coupled to and drive remote locking points  305  to the extended position into strikes located on the door vertical frame and/or, in the case of shoot bolts (not shown), drive the bolts vertically into strikes located on the door frame header or threshold. Simultaneously, gear teeth  364  on crank  327  drive rack  363  in crank return bar  321 . Crank return bar  321  defines chamber  317  that longitudinally contains half of compression spring  320 . The other half of compression spring  320  is contained in hollow  319  of crank return housing  336 . As crank return bar  321  is driven vertically up, the compartment defined by chamber  317  and hollow  319  shrinks, compressing spring  320 . As door handle  324  is released, torsion spring  335  biases operation bars  310  and  333  toward the extended position. Compression spring  320  expands the compartment defined by chamber  317  and hollow  319 , returning handle  324  to the neutral position. It is important to note that remote locking points  305  and/or shoot bolts (not shown) can be extended in this way regardless of whether dead bolt  302  is extended or retracted. 
     As shown in  FIGS. 25 and 26 , remote locking points  305  and/or shoot bolts (not shown) are retracted by a downward rotational input from door handle  324 , which is keyed to central spindle  325  and which protrudes through and is keyed to crank  327 . Crank  327  has lower arm  344  that rotates upward and contacts captured pin  329  in upper operation bar  310 , pushing upper operation bar  310  in an upward direction. Rack  330  of upper operation bar  310  drives pinion  331  rotationally, which in turn drives rack  332  in lower operation bar  333  in a downward direction. Operation bars  310  and  333  drive tie bars  311  via toothed racks  334 . Tie bars  311  drive remote locking points  305  and/or shoot bolts (not shown) to the retracted position, disengaging remote locking points  305  and/or shoot bolts (not shown) from strikes in the door frame. Simultaneously, crank  327  has lobe  345  on upper arm  328  that contacts corresponding lobe  346  on latch bolt base  347 , which retracts latch bolt  301  against the bias of compression spring  322 , thereby disengaging latch bolt  301  from strikes in the door frame (not shown). Simultaneously, gear teeth  364  on crank  327  drive rack  363  in crank return bar  321  in a vertically downward direction. Compression spring  320  contained in the shrinking compartment defined by chamber  317  and hollow  319  is compressed. Alternatively, with remote locking points  305  and/or shoot bolts (not shown) in the retracted position, door handle  324  can be rotated downward and latch bolt  301  retracted and compression spring  320  compressed. 
     As all bolts  301 ,  302 ,  305 ,  306  are retracted, the door  102  may now be rotated to the open position. As anti-slam plunger  303  moves away from the door frame, it is released to the extended position. Boss  308 , as shown in  FIG. 22 , on anti-slam plunger  303  moves into slot  309  on upper operation bar  310 , blocking movement of upper operation bar  310  and lower operation bar  333 , it effectively blocks extension of remote locking points  305  and/or shoot bolts (not shown). 
     Simultaneously as depicted in  FIGS. 20, 21, and 27-29  slot  315  anti-slam plunger  303  positions end  312  of blocker link  313  such that other end  314  rotates to a position in proximity to lobe  316  of dead bolt driver  318  to prevent dead bolt driver  318  from rotating and driving dead bolt  302 . As shown in  FIGS. 25 and 26 , when door handle  324  is released, torsion spring  335  biases operation bars  310  and  333  toward the retracted position while compression spring  320  drives crank return bar  321  which drives handle  324  back to the neutral position through rack  363  and gear teeth  364  on crank  327 . Simultaneously, lobe  345  in upper arm  328  of crank  327  rotates away from latch bolt lobe  346 , enabling compression spring  322  to extend latch bolt  301 . 
     As depicted in  FIGS. 30 and 31 , dead bolt  302  may be extended by a rotation of a thumb turn or thumb turn/lock cylinder common in the field (not shown). A spindle protrudes from the thumb turn into a slot  348  in dead bolt driver  318 . As dead bolt driver  318  rotates, boss  351  on opposite end  355  fits into cam slot  352  to drive dead bolt  302  in a horizontal translational motion. Cam slot  352  presents surface  353  oriented such that as dead bolt  302  reaches its maximum extension, boss  351  on dead bolt driver  318  reaches a toggle position in cam slot  352 , blocking dead bolt  302  from being back driven by a force placed on end surface  354  of dead bolt  302  parallel to the dead bolt translational motion. 
     Simultaneously, as dead bolt driver  318  rotates, opposite end  355  of dead bolt driver  318  pushes lobe  356  on lifter  357  in a rotational motion such that upper lobe  358  contacts and lifts spring loaded pawl  359 . As dead bolt  302  reaches full extension, lifter  357  is enabled to rotate down, dropping pawl  359  below notch  360  in dead bolt  302  to assist in blocking dead bolt  302  from being back driven. Simultaneously, lobe  316  of dead bolt driver  318  rotates away from end  337  of link  338 , enabling link  338  to rotate about pin  382 , and enabling boss  339  on another end of link  338  to rotate down. Slot  340  in stop bar  362  is positioned by boss  339  such that when boss  339  rotates downward, stop bar  362  moves vertically downward such that blocking lobe  341  at the other end of stop bar  362  moves in proximity with tab  342  on crank  327 , blocking rotation of crank  327  and inhibiting handle  324  from retracting latch bolt  301 , remote locking points  305 , and/or shoot bolts (not shown). 
     It is important to note that the dead bolt  302  can be extended or retracted regardless of whether the remote locking points  305  are extended or retracted. Simultaneously, lobe  316  of dead bolt driver  318  has corner  385  that is held in position by flat spring  386 . 
     Dead bolt  302  is retracted by a rotation of the thumb turn or thumb turn/lock cylinder common in the field (not shown). A spindle protrudes from the thumb turn into slot  348  in dead bolt driver  318 . As dead bolt driver  318  rotates, opposite end  355  of dead bolt driver  318  contacts lobe  356  on lifter  357 , rotating lifter  357  such that upper lobe  358  lifts spring loaded pawl  359  clear of notch  360  on dead bolt  302 . The timing is such that boss  351  on the end of dead bolt driver  318  then rotates to surface  366  in cam slot  352  of dead bolt  302 , driving dead bolt  302  to the retracted position. Simultaneously, as dead bolt driver  318  rotates to retract the dead bolt  302 , lobe  316  on dead bolt driver  318  contacts end  337  of link  338 , rotating boss  339  up which pushes slot  40  up lifting crank stop  62  vertically upward. This moves blocking lobe  341  away from tab  342  on crank  327 , enabling rotation of crank  327 . Simultaneously, lobe  316  on dead bolt driver  318  has surface  387  that is held in position by flat spring  386 . 
     It is common in the field to have left hand rotating doors and right hand rotating doors (not shown). Latch bolt  301  and anti-slam plunger  303  must be able to accommodate the opposing rotations of the doors either by offering separate hardware with opposing ramps, by offering interchangeability, or by making them non-handed. 
     As depicted in  FIGS. 32, 33, and 34 , latch bolt  301  of this embodiment is made interchangeable by restricting the translational movement of latch bolt  301  with torsion spring  368 . Torsion spring  368  has leg  369  extending from central coil  370 , which inserts into notch  371  in bent up wall  372  in cassette housing  343 . Central coil  370  wraps around standoff  373  secured to housing  343  and, in the free unloaded position, additional leg  374  extends perpendicular to the direction of travel of latch bolt  301 . This additional leg  374  of torsion spring  368  constrains latch bolt  301  at the extended position so as not to extend beyond the opening  375  in cassette housing  343 . Torsion spring  368  applies a resistance force to latch bolt base  347  as latch bolt end  376  is pulled from and clears housing opening  375 . Latch bolt end  376  is then rotated  180  degrees, positioning ramp  323  on latch bolt end  376  for the opposite handed door. Torsion spring  368  is allowed to return to its at rest position, pulling latch bolt end  376  back into housing opening  375 . Housing wall  378  and cover wall  379  hold latch bolt end  376  in rotational position. 
     As shown in  FIG. 35 , accommodation of left handed and right handed doors is accomplished in anti-slam plunger  303  of this embodiment with rotating paddle  341  that rotates about pin  384 . As depicted in  FIG. 35 , surface  383  of paddle  341  acts as the ramp for a left handed door. Detent  342  bears against end  367 , holding paddle  341  in place. As shown in  FIG. 34 , paddle  341  has rotated such that end  367  is held by detent  342  so that surface  388  now acts as the ramp surface for a right handed door, effectively making anti-slam plunger  303  non-handed. 
     Referring to  FIGS. 37-59  another embodiment of lock assembly  400  is depicted. In the depicted embodiment, latch bolt  401 , dead bolt  402 , and anti-slam plunger  403  are located in central cassette  404  with two or more remote locking points  405 . Remote locking points  405  can be permanently attached to center cassette  404  or attachable as a separate module as depicted in  FIG. 38 . Locks at the remote locking points  405  may be tungs, hooks, bolts, etc. that extend horizontally into a vertical door frame and/or may include shoot bolts (not shown) that extend vertically into a horizontal door frame header and threshold. 
       FIG. 39  depicts an example remote locking point  405 , hook  481  that is common in the field. This example should not be considered limiting. Remote locking points may include any type of remote locking point  405  known in the art. 
     Referring to  FIG. 40 , when a swinging door is in the open position, swung away from the door frame, anti-slam plunger  403  protrudes from the central cassette  404 . In this example, anti-slam plunger  403  is held in an extended position by compression spring  407 . 
     Referring to  FIG. 42 , boss  408 , on anti-slam plunger  403 , keys into slot  409  in upper operation bar  410  blocking translational movement of upper operation bar  410  when anti-slam plunger  403  is in an extended position. Upper operation bar  410  includes lower pin  489  that engages lever  492  via one of two slots  493 . Lever  492  is pivotally coupled at pivot pin  490 . Opposing slot  493  of lever  492  engages pin  491  and lower operation bar  433 . 
     Referring to  FIG. 39 , remote locking points  405  are coupled to operation bars  410  and  433  by tie bars  411  whereby remote locking points  405  are prevented from being extended. Simultaneously, referring to  FIG. 40 , blocker link  413  rotates about pin  482 . End  412  of blocker link  413  is held in position by slot  415  in the side of anti-slam plunger  403  such that other end  414  of blocker link  413  is positioned with respect to lobe  416  of dead bolt driver  418  to prevent dead bolt driver  418  from rotating and extending dead bolt  402 . 
     Referring to  FIG. 41 , the door is closed and anti-slam plunger  403  comes into contact with a strike in the door frame (not shown) which depresses anti-slam plunger  403  inwardly into central cassette  404 . Boss  408 , best seen in  FIG. 42 , on anti-slam plunger  403  clears slot  409  in upper operation bar  410  allowing translational movement of upper operation bar  410  which then drives lower operation bar  433  in the opposite direction through lever  492  and pins  490 ,  491  thus extending remote locking points  405 . Simultaneously, as depicted in  FIG. 41 , slot  415  in the anti-slam plunger  403  positions blocker link end  412  so that blocker link  413  rotates about pin  482  thus rotating other blocker link end  414  clear of lobe  416  of dead bolt driver  418  thus allowing rotational movement of dead bolt driver  418  to extend dead bolt  402  from central cassette  404 . 
     The effect of this operation is that when the door is open, remote locking points  405  and dead bolt  402  are blocked from extending, thus preventing remote locking points  405  and dead bolt  402  from “slamming” into and damaging the door frame as the door is closed. However, remote locking points  405  and dead bolt  402  are freed to extend when the door is closed to secure the door in the closed position. 
     Latch bolt  401  is biased toward an extended position by compression spring  422 . Compression spring  422  loaded latch bolt  401  presents angled ramp surface  423  that causes latch bolt  401  to depress as it contacts a strike in the door frame, and to extend once it reaches a slot in the strike (not shown) latching the door, similar to latch bolts common in the field. 
     Referring to  FIGS. 43 and 44 , remote locking points  405  and/or shoot bolts (not shown) are extended by an upward rotational input from a door handle  424  (common in the field) that is keyed to central spindle  425  (common in the field). Spindle  425  protrudes and is keyed to crank  427  in central cassette  404 . Crank  427  includes upper arm  428  that rotates downwardly to contact captured pin  429  of upper operation bar  410  and to push upper operation bar  410  in a downward direction. 
     Referring to  FIGS. 45 and 46 , operation bars  410  and  433  are connected to tie bars  411  by tie bar pins  494 . Tie bars  411  are connected to and drive remote locking points  405  to the extended position into strikes located on the door vertical frame and/or, in the case of shoot bolts (not shown), drive shoot bolts (not shown) vertically into strikes located on the door frame header or threshold. Simultaneously, as depicted in  FIG. 49 , gear teeth  464  on crank  427  drive rack  463  in crank return bar  421 . Crank return bar  421  defines chamber  417  that longitudinally contains half of compression spring  420 . The other half of compression spring  420  is contained in hollow  419  of crank return housing  436 . As crank return bar  421  is driven vertically up, the compartment formed by chamber  417  and hollow  419  shrinks in length compressing spring  420 . As door handle  424  is released torsion spring  435  holds operation bars  410  and  433  in the extended position. Compression spring  420  resiliently expands the compartment formed by chamber  417  and hollow  419  returning handle  424  to the neutral position. It is notable that remote locking points  405  and/or shoot bolts (not shown) can be extended in this way regardless of whether the dead bolt  402  is extended or retracted. 
     Referring again to  FIGS. 45 and 46 , remote locking points  405  and/or shoot bolts (not shown) are retracted by a downward rotational input from door handle  424  keyed to central spindle  425  which protrudes through and is keyed to crank  427  in central cassette  404 . Crank  427  includes lower arm  444  that rotates upwardly and contacts captured pin  429  in upper operation bar  410  and pushes upper operation bar  410  in an upward direction. Pin  489  of upper operation bar  410  then drives lever  492  rotationally which drives pin  491  in the lower operation bar  433  in a downward direction. Operation bars  410  and  433  drive tie bars  411  via tie bar pin  494 . Tie bars  411  drive remote locking points  405  and/or shoot bolts (not shown) to the retracted position disengaging remote locking points  405  and/or shoot bolts (not shown) from strikes in the door frame. Simultaneously, crank  427  has lobe  445  on upper arm  428  that contacts corresponding lobe  446  on latch bolt base  447  which retracts latch bolt  401  that is preloaded by compression spring  422 , disengaging latch bolt  401  from strikes in the door frame (not shown). Also simultaneously, as depicted in  FIG. 48 , gear teeth  464  on crank  427  drive rack  463  in crank return bar  421  in a vertically downward direction. Compression spring  420  contained in the shrinking compartment formed by chamber  417  and hollow  419  is compressed. Alternatively, with remote locking points  405  and/or shoot bolts (not shown) in the retracted position, door handle  424  can be rotated downwardly and latch bolt  401  retracted and compression spring  420  compressed. 
     As all bolts  401 ,  402 , and  405  and/or  406  are retracted the door panel may now be rotated to the open position. As anti-slam plunger  403  moves away from the door frame it is released to the extended position. Boss  408 , as depicted in  FIG. 42 , on anti-slam plunger  403  moves into slot  409  on upper operation bar  410  blocking movement of upper operation bar  410  and lower operation bar  433 , effectively blocking extension of remote locking points  405  and/or shoot bolts (not shown). Simultaneously, as depicted in  FIGS. 40 &amp; 41 , slot  415  in anti-slam plunger  403  positions end  412  of blocker link  413  such that other end  414  of blocker link  413  rotates to a position in proximity to lobe  416  of dead bolt driver  418  to prevent dead bolt driver  418  from rotating and driving dead bolt  402 . 
     As shown in  FIGS. 47 and 48 , when door handle  424  is released torsion spring  435  holds operation bars  410  and  433  in the retracted position while compression spring  420  drives crank return bar  421  which drives handle  424  back to the neutral position through rack  463  and gear teeth  464  on crank  427 . Simultaneously, lobe  445  in upper arm  428  of crank  427  rotates away from latch bolt lobe  446  allowing compression spring  422  to extend latch bolt  401 . 
     As in  FIGS. 50 and 51 , dead bolt  402  is extended by a rotation of a thumb turn or thumb turn/lock cylinder (common in the field, not shown). A spindle (common in the field) protrudes from a thumb turn (not shown) into a slot  448  in dead bolt driver  418 . As dead bolt driver  418  rotates, boss  451  on opposite end  455  fits into cam slot  452  driving dead bolt  402  in a horizontal translational motion. Cam slot  452  presents surface  453  such that as dead bolt  402  reaches its maximum extension boss  451  on dead bolt driver  418  reaches a toggle position in cam slot  452  blocking dead bolt  402  from being back driven by a force applied to end surface  454  of the dead bolt  402  parallel to dead bolt  402  translational motion. Simultaneously, lobe  416  of dead bolt driver  418  rotates away from end  437  of link  438  allowing link  438  to rotate about pin  482  and boss  439  on another end of link  438  to rotate downwardly. Slot  440  in stop bar  462  is positioned by boss  439  such that when boss  439  rotates downward, stop bar  462  moves vertically downward such that blocking lobe  441  at the other end of stop bar  462  moves in proximity with tab  442  on crank  427  blocking rotation of crank  427  and handle  424  from retracting latch bolt  401 , remote locking points  405 , and/or shoot bolts (not shown). 
     It is important to note that dead bolt  402  can be extended or retracted regardless of whether remote locking points  405  are extended or retracted. Simultaneously, lobe  416  of dead bolt driver  418  has corner  485  that is held in position by spring  486 . 
     Dead bolt  402  is retracted by a rotation of the thumb turn or thumb turn/lock cylinder (common in the field, not shown). A spindle (common in the field) protrudes from the thumb turn into slot  448  in dead bolt driver  418 . As dead bolt driver  418  rotates, boss  451  on the end of dead bolt driver  418  then rotates to surface  466  in cam slot  452  of dead bolt  402  that drives dead bolt  402  to the retracted position. Simultaneously, as dead bolt driver  418  rotates to retract dead bolt  402 , lobe  416  on dead bolt driver  418  contacts end  437  of link  438  rotating boss  439  upwardly which pushes slot  440  up, lifting crank stop  462  vertically upward. This moves blocking lobe  441  away from tab  442  on crank  427  allowing rotation of the crank  427 . Simultaneously, lobe  416  on dead bolt driver  418  has surface  487  that is held in position by spring  486 . 
     It is common in the field to have left hand rotating doors and right hand rotating doors (not shown). Latch bolt  401  and anti-slam plunger  403  in accordance with the invention are able to accommodate the opposing rotations of the doors either by offering separate hardware with opposing ramps, by offering interchangeability, or by making them non-handed. 
     As depicted in  FIGS. 52, 53 and 54 , latch bolt  401 , in one embodiment of the invention is made interchangeable by restricting the translational movement of the latch bolt  401  with torsion spring  468 . Torsion spring  468  has leg  469  extending from central coil  470  that inserts into notch  471  in bent up wall  472  in cassette housing  443 . Central coil  470  raps around standoff  473  secured to housing  443  and in the free unloaded position additional leg  474  extends perpendicular to the direction of travel of latch bolt  401 . Additional leg  474  of torsion spring  468  constrains latch bolt  401  at the extended position so as not to extend beyond opening  475  in cassette housing  443 . Torsion spring  468  applies a resistance force to latch bolt base  447  as latch bolt end  476  is pulled from and clears housing opening  475 . Latch bolt end  476  is then rotated one hundred eighty degrees positioning the ramp  423  on the latch bolt end  476  for the opposite handed door. The torsion spring  468  is allowed to return to its at rest position pulling the latch bolt end  476  back into the housing opening  475 . Housing wall  478  and cover wall  479  hold the latch bolt end  476  in rotational position. 
     As depicted in  FIG. 55 , anti-slam plunger  403  according to an embodiment of the invention includes a rotating paddle  441  that rotates about a pin  484 . This configuration makes anti-slam plunger  403  reversibly handed. As depicted in the upper section, surface  483  of paddle  441  acts as a ramp for a left hand door. Detent  442  bears against end  467  holding paddle  441  in place. As depicted in the lower section, paddle  441  has rotated such that end  467  is held by détente  442  so that surface  488  now acts as the ramp surface for a right hand door, effectively making the anti-slam plunger  403  non-handed. 
     As depicted in  FIGS. 56, 57 and 58  another embodiment of the invention includes additional anti-backdrive protections. Anti-backdrive bolt  495  is present to prevent back drive of remote locking points  405  and  406  when locking points  405  and  406  are in the extended position. Operation bar  410 , which drives the locking points  405  and  406 , presents locking pin  498 . As depicted in  FIG. 56 , when dead bolt  402  is in the extended position, anti-backdrive bolt  495  is guided into position by tab  496  and slot  497  held in position by compression spring  500  within slot  497 . As shown in  FIG. 57 , as remote locking points  405  and  406  are extended into position locking pin  498  contacts ramp  499  on anti-backdrive bolt  495  pushing anti-backdrive bolt  495  in a direction compressing compression spring  500  and allowing locking pin  498  to slide by anti-backdrive bolt  495 . Referring to  FIG. 58 , once locking pin  498  is past anti-backdrive bolt  495 , undercut surface  502  of anti-backdrive bolt  495  prevents remote locking points  405  and  406  from backdriving to the retracted position. 
     As depicted in  FIGS. 60-65 , in another embodiment of the invention latchbolt  510  includes integrated latch lubrication strip  512 . Referring to  FIG. 60 , wedge shaped latchbolt  510  is operably disposed in cassette  516 , which contains a latch actuating mechanism as described in embodiments above. Latchbolt  510  contacts a strike plate in a door frame (not shown) in such a way as to press spring loaded latchbolt  510  into cassette  516  until latchbolt  510  reaches an opening in the strikeplate, enabling spring loaded latchbolt  510  to engage in the strikeplate opening and secure the door panel to the door frame. 
     Embodiments of the invention inhibit the scratching and marring of the strike plate and reduce the friction, roughness, and noise of operation of closing. 
     Lubrication strip  512  is fitted into slot  520  defined in latchbolt  510 . Lubrication strip  512 , in this example surrounds four of five generally planar surfaces of latchbolt  510  that may contact a strike plate (not shown). Referring to  FIGS. 62 and 65 , lubrication strip  512  presents retaining ridges  522  and alignment ridges  524 . Latchbolt  510  presents complementary indentations  526 ,  528  into which retaining ridges  522  and alignment ridges  524  may be received to secure lubrication strip  512  to latchbolt  510 . Accordingly, lubrication strip, as seen in  FIGS. 60, 62 and 64  extends outwardly from latchbolt  510  slightly adjacent the four surfaces of latchbolt  510  that may contact a strikeplate thus preventing metal to metal contact between latchbolt  510  and the strike (not shown). 
     Lubrication strip  512  can be formed from a material that will not scratch or mar the strike plate and has a low coefficient of friction. In a preferred embodiment, lubrication strip  512  may be made from polyacetal or polyoxymethylene polymers. It will be appreciated, however, that any other material with a sufficiently low coefficient of friction and suitable durability qualities may be used, such as for example, high-density polyethylene. Slot  520  may be made of a small enough dimension that the structural integrity of latchbolt  10  is not compromised and it retains sufficient strength to resist forced entry and cyclical wear. 
     Various modifications to the invention may be apparent to one of skill in the art upon reading this disclosure. For example, persons of ordinary skill in the relevant art will recognize that the various features described for the different embodiments of the invention can be suitably combined, un-combined, and re-combined with other features, alone, or in different combinations, according to the spirit of the invention. Likewise, the various features described above should all be regarded as example embodiments, rather than limitations to the scope or spirit of the invention. Therefore, the above is not contemplated to limit the scope of the present invention. 
     For purposes of interpreting the claims for the present invention, it is expressly intended that the provisions of Section 112, sixth paragraph of 35 U.S.C. are not to be invoked unless the specific terms “means for” or “step for” are recited in a claim.