Abstract:
A lock assembly including a latchbolt that may be effectively lengthened to accommodate varied backset distances for doors. The lock assembly may include a housing, a latchbolt including an attachment member, an extension member, a retractor element, and an operator. The extension member may be mounted to the attachment member to extend from the latchbolt for effective lengthening of the latchbolt. The retractor element, operatively responsive to the operator, is disposed within the housing for linear reciprocating movement to move the latchbolt, and is selectively engageable with the attachment member or with the extension member. The extension member defines a recess adapted to receive the attachment member. A latch case may receive the latchbolt, and a cylindrical sleeve may receive the latch case and the latchbolt when the extension member is in use to increase the backset dimension.

Description:
BACKGROUND 
       [0001]    Embodiments of an adjustable backset lockset described herein relate generally to a lockset for use with a door, and more particularly to a lockset with an adjustable backset distance for use with doors having different backset distances. 
         [0002]    “Backset” is the distance between the edge of a door and the relatively transverse axis of rotation about which the latch operator moves for extending and retracting a latch bolt of a latch mechanism. Backset has been standardized by the industry. Standard backsets for commercial door openings are 2⅜ inches and 2¾ inches. 
         [0003]    Manufacturers of latch constructions have satisfied the demand for latchsets having standard backset measurements by producing and marketing two different models of latch constructions. However, maintaining an inventory of assemblies and components for locksets having two different backsets is inefficient. 
         [0004]    An alternative is providing adjustable latch mechanisms, which have become an accepted feature of tubular locksets. Unfortunately, adjustable latch mechanism solutions for this application have typically been of insufficient strength for a Grade 1 or Grade 2 commercial lockset capable of meeting ANSI standards for “cylindrical” locks. 
         [0005]    For the foregoing reasons, there is a need for a new lockset which is easily adjusted for mounting on doors of differing backset distances. Such adjustment should be effected in a way that provides the assembly with inherent strength. Ideally, the new lockset construction would allow for relatively quick and easy selective adjustment between the two standard backset measurements. 
       SUMMARY 
       [0006]    In accordance with an embodiment of an adjustable backset lockset, a lock assembly is provided comprising a housing, a latchbolt including an attachment member, an extension member, a retractor element, and an operator. The extension member has a length and is removeably mountable to the attachment member for effective lengthening of the latchbolt. The retractor element is disposed within the housing for linear reciprocating movement and is selectively engageable with the attachment member or with the extension member for movement with the retractor element. The operator is operatively connected to the retractor element for facilitating selective reciprocation of the retractor element for moving the latchbolt between a latched position and an unlatched position. 
         [0007]    In accordance with another embodiment of an adjustable backset lockset, a lock assembly is provided comprising a housing, a latchbolt including an attachment member, means for effective lengthening of the latchbolt, means for linear reciprocating movement disposed within the housing, and a means for facilitating selective reciprocation of the retractor element. The effective lengthening means is removeably engageable with the attachment member. The linear reciprocating movement means is selectively engageable with the attachment member or with the effective lengthening means for movement with the linear reciprocating movement means. The means for facilitating selective reciprocation of the retractor element is for moving the latchbolt between a latched position and an unlatched position. 
         [0008]    In accordance with another embodiment of an adjustable backset lockset, an extension member for a latchbolt of a lock assembly is provided. The latchbolt includes an attachment member. The lock assembly includes a retractor element for linear reciprocating movement and engageable with the attachment member. The extension member includes a body and a tail piece. The body has a longitudinal axis, a first end, and a second end. The tail piece is mounted to the body and extends from the first end, and is dimensioned so as to function in place of the attachment member when engaging the retractor element. The body defines a recess adapted to receive the attachment member from the second end and to transfer force to the attachment member during linear movement of the extension member as urged by the retractor. 
         [0009]    In accordance with another embodiment of an adjustable backset lockset, a latchbolt assembly comprises a latchbolt including a bolt tail and an extension member. The extension member is removeably mountable to the bolt tail for effectively lengthening the latchbolt. 
         [0010]    In accordance with another embodiment of an adjustable backset lockset, a method of adjusting the backset distance of a lock assembly is provided. The method comprises providing a lock assembly having a housing, a latchbolt including an attachment member, a retractor element disposed within the housing for linear reciprocating movement, and an operator operatively connected to the retractor element for facilitating selective reciprocation of the retractor element for moving the latchbolt between a latched position and an unlatched position. An extension member is provided that is sized and shaped to be engageable with the attachment member and with the retractor element. The extension member is secured to the attachment member and the extension member is engaged with the retractor element for movement with the retractor element. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    For a more complete understanding, reference should now be had to the embodiments shown in the accompanying drawings and described below. In the drawings: 
           [0012]      FIG. 1  is an exploded perspective view of a lockset assembly according to one embodiment of an adjustable backset lockset. 
           [0013]      FIG. 2  is a close-up perspective view of the chassis assembly shown in  FIG. 1 . 
           [0014]      FIG. 3  is an exploded perspective view of the chassis assembly shown in  FIG. 2 . 
           [0015]      FIG. 4  is a side view of one embodiment of a latch assembly as mounted to the chassis assembly shown in  FIG. 2 , shown in a partial sectional side view. 
           [0016]      FIG. 5  is a perspective view of the latch assembly shown in  FIG. 4 . 
           [0017]      FIG. 6  is a perspective view of one embodiment of an extension clip. 
           [0018]      FIG. 7  is an exploded perspective view of the latch retractor and the latch assembly shown in  FIG. 4 , the extension clip shown in  FIG. 6 , and an embodiment of a sleeve. 
           [0019]      FIG. 8  is a perspective view of the extension clip shown in  FIG. 6  mounted to the latch assembly shown in  FIG. 5 . 
           [0020]      FIG. 9  is a perspective view of the latch assembly and extension clip shown in  FIG. 8  with the sleeve shown in  FIG. 7 . 
           [0021]      FIG. 10  is a side view of the latch assembly, extension clip, and sleeve shown in  FIG. 9  as mounted to the chassis assembly shown in  FIG. 2 , shown in a partial sectional side view. 
           [0022]      FIG. 11  is a perspective view of the assembled lockset assembly shown in  FIG. 1 . 
           [0023]      FIG. 12A  is a plan view of a second embodiment of an extension clip mounting arrangement. 
           [0024]      FIG. 12B  is a side view of the extension clip and mounting arrangement shown in  FIG. 12A . 
           [0025]      FIG. 13A  is a plan view of a third embodiment of an extension clip and mounting arrangement. 
           [0026]      FIG. 13B  is a side view of the extension clip and mounting arrangement shown in  FIG. 13A . 
           [0027]      FIG. 14A  is a plan view of a fourth embodiment of an extension clip and mounting arrangement. 
           [0028]      FIG. 14B  is a side view of the extension clip and mounting arrangement shown in  FIG. 14A . 
       
    
    
     DESCRIPTION 
       [0029]    The embodiments of an adjustable backset arrangement are for use in a conventional lockset such as, for example, the locksets described by U.S. Pat. No. 4,920,773 and U.S. Pat. No. 6,131,970, the contents of both of which are incorporated herein by reference. Moreover, it is understood that the overall construction of the lockset assembly is not critical and, for purposes of illustration, may be as described herein or in the above-referenced U.S. patents. Accordingly, although exemplary embodiments will be described in detail herein with respect to an adjustable backset function, detailed explanations of the functioning of all of the lockset components are deemed unnecessary for understanding by one of ordinary skill in the art. 
         [0030]    Certain terminology is used herein for convenience only and is not to be taken as a limitation. For example, words such as “upper,” “lower,” “left,” “right,” “horizontal,” “vertical,” “upward,” and “downward” merely describe the configuration shown in the figures. Indeed, the components may be oriented in any direction and the terminology, therefore, should be understood as encompassing such variations unless specified otherwise. 
         [0031]    Referring now to the drawings, wherein like reference numerals designate corresponding or similar elements throughout the several views, a cylindrical lockset assembly for use with a conventional opening in a door (not shown) is shown in  FIG. 1  and generally designated at  20 . The cylindrical lockset assembly  20  comprises an inside subassembly  22  and an outside subassembly  24 . The inside subassembly  22  includes a rose plate  26 , a rose  28 , and a lever  30 . The outside subassembly  24  includes a rose plate  32 , a rose  34 , and a lever  36 . A chassis  40  is located between the inside subassembly  22  and the outside subassembly  24 . A latch assembly  42  is positioned for operable attachment to the chassis  40  and includes a latchbolt  44  that extends outwardly from a face plate  46  in an extended, or latched, position. 
         [0032]    The rose plates  26 ,  32  are each formed in a generally circular configuration and having an axial central opening  48 ,  50 . Two pair of holes  52 ,  54  are formed on the periphery of each rose plate  26 ,  32 . One pair of holes  52  is adapted to pass bolts  56  which extend through the door. The other pair of holes is provided for receiving screws (not shown) for fastening the rose plates  26 ,  32  to their respective roses  28 ,  34 . A pair of inwardly extending tabs  58  is formed in the outside rose plate  32  by punching holes through the outside rose plate  32 . 
         [0033]    The roses  28 ,  34  are each formed in a generally circular configuration and include a side wall  60 ,  62  defining an inner dish-like cavity in the inside surface of the rose  28 ,  34 . An axial opening  64 ,  66  is formed through each rose  28 ,  34  and extends through rotating spindles  68 ,  70  which extend outwardly from the roses. A return spring  72  is positioned in the cavity of each rose  28 ,  34 . As described above, the rose plates  26 ,  32  are fastened to the roses  28 ,  34  using screws for retaining the springs  72  within the cavity. 
         [0034]    The levers  30 ,  36  each include a handle  74 ,  76  which is formed integrally with a hub  78 ,  80 . Each hub  78 ,  80  has an axial opening  81  which, in a locking lockset, may communicate with an axial opening formed through the handle for receiving a turn button or lock cylinder for locking of the latchbolt in the extended, or latched, position. Further, although levers are shown, it is understood that other latch operating means are suitable, such as a doorknob or the like. 
         [0035]    Referring now to  FIGS. 2 and 3 , the chassis  40  comprises a housing  90  for accommodating a U-shaped retractor  95  and opposed rollback sleeves  92 ,  94 . The housing  90  includes a case  96  and opposed end caps  98 . The case  96  is formed in a U-shaped configuration having a base  100  and a pair of legs  102  formed integrally with the base  100 . The legs  102  have inwardly bent ends  101 . Two pairs of opposed tabs  103  extend transversely from each leg  102 . 
         [0036]    The end caps  98  are generally circular and have a central axial opening  104 . Four spaced notches  106  are formed in the end caps  98  for receiving the tabs  103  on the case  96 . 
         [0037]    The retractor  95  is formed with a base  108  having a cam surface  110  on each side and a pair of spaced, parallel arms  112 . The ends of the arms  112  are formed with a pair of opposed outer lips  114 , shown in  FIG. 4 . 
         [0038]    The sleeves  92 ,  94  are each formed with a pair of camming elements  93  at one end as shown in  FIG. 3 . The camming elements  93  are formed by rolling back portions of the sleeves  92 ,  94  which extend from the end of the cylindrical portions. The sleeves  92 ,  94  are rotatably received in the openings  104  in the end caps  98  as shown in  FIGS. 2 and 3 . 
         [0039]    In assembling the components of the chassis  40 , the rollback sleeves  92 ,  94  are positioned so that the camming elements  93  are located adjacent the cam surfaces  110  on each side of the retractor  95 . The sleeves  92 ,  94  and retractor  95  are then located in the case  96  between the legs  102  and close to the inner surface of the base  100 . The ends of two springs  120  are positioned over a pair of spaced posts  122  extending outwardly from the base  100  of the case  96 . The other ends of the springs  120  engage a retainer  124 , which fits in a corresponding opening in the rear of the retractor  95  thereby placing the springs  120  in a contained position for subsequent compression. To complete the housing  90 , the end caps  98  are then slipped over the sleeves  92 ,  94  with the tabs  103  on the case  96  being inserted in the notches  106  in the end caps  98  and twisted. The retractor  95 , the inward ends of the sleeves  92 ,  94 , the springs  120  and the retainer  124  are contained within the housing  90 . The sleeves  92 ,  94  extend outwardly from the openings  104  in the end caps  98 . In this arrangement, the lips  114  of the retractor  95  are exposed through the housing  90 . 
         [0040]    Referring now to  FIG. 4 , the latch assembly  42  includes the latch bolt  44 , the face plate  46 , and a latch case  130 . The latch case  130  is secured at one end to the face plate  46 . The latchbolt  44  is contained partially within the latch case  130  and extends outwardly of the latch case to the extended position through an opening in the face plate  46 . The latchbolt  44  is retractable into the latch case  130  to a retracted, or unlatched, position. Thus, the latchbolt  44  is movable between the extended or latched position and the retracted or unlatched position. The latch bolt  44  includes a bolt tail  132  which extends from the rear of the latch case  130 . The end of the bolt tail  132  is T-shaped and has arms  134 ,  135 , as seen in  FIG. 5 . The bolt tail  132  is designed to be positioned through the opening of the retractor housing  90  with the arms  134 ,  135  located behind the lips  114  of the retractor  95 . As shown in  FIG. 4 , the bolt tail  132  is adapted to be of a length to allow the arms  134 ,  135  to engage behind the lips  114  of the retractor  95 . In this arrangement, upon rotation of one of the sleeves  92 ,  94 , the camming elements  93  ( FIG. 3 ) will engage the cam surfaces  110  on the retractor  95  to urge the retractor  95  inwardly against the biasing of the springs  120 . As the retractor  95  is moved inwardly, the bolt tail  132  is pulled with the retractor  95  to withdraw the latchbolt  44  to the retracted position. 
         [0041]    An embodiment of a tail extension clip  200  is shown in  FIG. 6 . The tail extension clip  200  includes a base  202 , a magnet  204  recessed into the base, a clip tail piece  206 , and a pair of protruding fingers  208 . A channel  210  together with an opening  212  that is formed between protruding fingers  208  define a recessed area that is substantially the shape of a “T.” The channel  210  and opening  212  are sized to receive the bolt tail  132  and arms  134 ,  135 , which may be a standard size, and as previously noted are also substantially T-shaped. The clip tail piece  206  includes arms  214 ,  215  that also substantially form a T-shape and result in the clip tail piece  206  being a functional substitute for the bolt tail  132  with respect to connection with the retractor  95 , as discussed further below. 
         [0042]    The extension clip  200  may be attached to the bolt tail  132  when the backset dimension is to be increased. The extension clip  200  extends from the bolt tail, effectively lengthening the latchbolt  44 . Such an increase may be, for example, from 2⅜ to 2¾, which as previously discussed are standard dimensions of backsets. To accomplish this, in one embodiment the extension clip  200  is placed adjacent to the bolt tail  132 , as shown in  FIG. 7 . The channel  210  receives the bolt tail  132  and the protruding fingers  208  slide underneath the arms  134 ,  135  to prevent movement of the bolt tail  132  longitudinally along the axis of the latchbolt  44  when the bolt tail  132  is attached to the clip  200 . The extension clip  200  is sized and shaped to magnetically attach to one side of the bolt tail  132  by means of the magnet  204  embedded into the base  202 . An auxiliary latch case, or sleeve  220 , is passed over the latch assembly  42 , as shown in  FIG. 8 , effectively lengthening the latch case  130 . The sleeve  220  has a diameter sized to allow the bolt tail  132 , extension clip  200 , and latch case  130  to fit within the interior of the sleeve  220 . The sleeve  220  has a pair of sleeve ears  222 . The sleeve ears  222  engage the chassis  40  to secure the latch assembly  42  to the chassis ( FIG. 10 ). 
         [0043]    The addition of the extension clip  200  and the sleeve  220  increases the backset dimension. As assembled, in one embodiment the length of the tail extension clip  200  beyond the existing bolt tail is ⅜ inch. This is to accommodate the ⅜ inch difference between the standard backset dimension. Additionally, the sleeve  220  is a length that accommodates the additional length of the extension clip  200 . These dimensions may enable the user to alter the backset dimension from 2⅜ inches to 2¾ inches easily and quickly. It should be understood that in the event the cylindrical lock assembly  20 , installed on a door with a 2¾ backset, were to be used on another door where the backset dimension was 2⅜ inches, the assembly may be removed from the door and reassembled without the extension clip  200  and sleeve  220  to accommodate the smaller backset dimension of 2⅜ inches. 
         [0044]    In assembling the components of the cylindrical lockset assembly  20  of  FIG. 1  for a relatively short backset dimension as shown in  FIGS. 4 and 5 , such as 2⅜ inch, the latch assembly  42  is first positioned within an opening in the edge of a door. The edge opening communicates with a larger transverse opening in the door. The chassis  40  is inserted through the larger opening. As the chassis  40  is moved into the larger opening, the chassis  40  engages and becomes attached to the sleeve ears  144  extending from the rear of the latch case  130 . The sleeve ears  144  fit behind the bent ends  101  of the legs  102  of the case  96 . In this position, the housing  90  is located within the door opening and the sleeves  92 ,  94  extend from opposite sides of the door. The bolt tail  132  is then attached to the lips  114  of the retractor  95  in the manner previously described and the face plate  96  is secured to the edge of the door. 
         [0045]    Alternatively, to assemble the components of the cylindrical lockset assembly  20  for a relatively long backset dimension as shown in  FIGS. 7-10 , such as 2¾ inch, the extension clip  200  is mounted to the bolt tail  132  and the sleeve  220  is then slipped over the original latch case  130 . The sleeve  220  is longer than the latch case  130 , but the bolt tail  132  and extension clip  200  are dimensioned so that the clip tail piece  204  extends from the rear of the sleeve  220 . The modified latch assembly may then be connected to the chassis  40  by engaging the ears  222  extending from the rear of the sleeve  220  behind the bent ends  101  of the legs  102  of the case  96 . The extension clip  200 , and in particular the clip tail piece  204 , is then attached to the lips  114  of the retractor  95  in the manner previously described for the bolt tail  132  attachment to the lips  114  for the shorter backset, and the face plate  46  is secured to the edge of the door. 
         [0046]    Next, the outside rose plate  32  is slid over the outside end cap  98 . As seen in  FIG. 2 , both end caps  98  have longitudinally-spaced lateral grooves  146  for receiving the rose plates  26 ,  32 . The rose plates  26 ,  32  are adapted to be engaged in either one of the two grooves  146  in the end caps  98  to accommodate different door thicknesses. The outside rose plate  32  has an oblong central opening  50 . The oblong opening  50  has a larger portion of sufficient dimension to allow the rose plate  32  to fit over the outside end cap  98  of the latch housing  90 . The oblong central opening  50  also has two opposed flats which define a narrower portion of the oblong central opening  50 . This shape of the opening  50  allows the outside rose plate  32  to be assembled eccentrically with respect to the housing  90  with the narrower portion of the oblong central opening  50  centered over the housing  90  and the flats seated in one set of grooves  146 . The outside rose plate  32  is thus aligned with the appropriate groove  146  in the end cap  98 , the outermost groove for a thick door or the innermost groove for a thin door, and moved laterally to a concentric position with respect to the housing  90 . Once the outside rose plate  32  is so engaged, the housing  90  is fixed rotationally and axially with respect to the outside rose plate  32 . The outside end cap  98  of the housing  90  also includes opposed longitudinal ribs  148  and the oblong central opening  50  in the outside rose plate  32  includes opposed notches. The notches are adapted to receive the corresponding longitudinal rib  148  when the outside rose plate  32  is engaged in either of the sets of grooves  146  as described above. This configuration further strengthens the assembly against rotation of the outside rose plate  32  with respect to the housing  90 . 
         [0047]    The outside rose  34  fits against the outside rose plate  32 . Openings in the outside rose plate  32  are aligned with threaded holes in the outside rose  34  for use with screws for securing the outside rose plate  32  to the outside rose  34 . 
         [0048]    The inside rose plate  26  is secured to the inside rose  28  and then moved over the inside end cap  98  and against the door surface. Bolt holes in the inside rose  28  are aligned with threaded bolt holes of the outside rose  34 . The threaded ends of the bolts  56  are then passed through the unthreaded holes in the inside rose  28  and into the threaded holes of the outside rose  34 . The bolts  56  are then tightened to draw the rose plates  26 ,  32  and roses  28 ,  34  to a secure assembled position on opposite sides of the door whereby the heads of the bolts  52  come to rest in countersunk holes in the outer face of the inside rose  28 . It is noted that in attaching the roses  28 ,  34  in the manner described above, protrusions on the sleeves  92 ,  94  are aligned with corresponding slots (not shown) in the spindles  68 ,  70  such that the sleeves  92 ,  94  and spindles  68 ,  70  rotate together within the lockset assembly  20 . 
         [0049]    To complete the assembly, an inside rose scalp  152  is slipped over the inside spindle  68  and the inside rose  28  and the inside lever  30  is secured onto the inside spindle  68 . Similarly, an outside rose scalp  154  is placed over the outside spindle  70  and the outside rose  34  and the outside lever  36  is secured onto the spindle  70 . In attaching the levers  30 ,  36 , the axial hub openings  79 ,  81  are positioned over the spindles  68 ,  70 , which include a pair of diametrically opposed longitudinal slots  156 . The slots  156  receive corresponding ribs formed in the levers  30 ,  36  to facilitate rotation of the spindles  68 ,  70  upon actuation of the levers  30 ,  36 . The hub openings  79 ,  81  are also formed with transverse depressions and are positioned for alignment with transverse slots formed in spindles  68 ,  70 . Spring-biased detents or catch plates (not shown) extend through the slots and into the depressions to retain the levers  30 ,  36  on the sleeves  92 ,  94 . The assembly  20  is shown in its assembled form in  FIG. 11 . 
         [0050]    Embodiments of the extension clip for an adjustable backset lockset utilizing different means than magnetic retention are available for mounting the extension clip  202  to the latch assembly  42 , and more specifically, to the bolt tail  132 . A snap fit  230  is shown in  FIGS. 12A and 12B . To provide the snap fit  230 , a protrusion  232  is provided along the top edge of the protruding fingers  208 , extending inward towards the channel  210 . When the bolt tail  132  is inserted into the channel  210 , the edges of the arms  134 ,  135  that are away from the clip tail piece  206  are obstructed by the protrusion  232 , and the bolt tail  132  is restrained in the channel  210 . 
         [0051]    Another embodiment for mounting of the extension clip  202  is with mechanical deformation of the extension clip  202  to provide a mechanically restrained connection  240  as shown in  FIGS. 13A and 13B . A slot  242  that opens toward the channel  210  is provided in the fingers  208  at a distance from the bottom of the slot  242  just greater than the thickness of the bolt tail  132 . A flat member  244 , which may be for example, a thin piece of aluminum, may be inserted into the slot  242  such that it extends the length of the channel  210 . On the opposite side of the channel  210  the extension clip  200  may be deformed along the length of the top of the channel  210 , or, as shown, the deformation may be periodic by “staking,” and intermittent stakes  246  may be provided for the length of the channel  210 . With the member  244  positioned in the slot  242  and beneath the stakes  246 , the bolt tail  132  is pinned in place, restrained from moving out of the channel  210 . 
         [0052]    Yet another embodiment for mounting of the extension clip  202  is by use of positively applied force with a threaded connection  250  as shown in  FIGS. 14A and 14B . A threaded fastener, such as a Phillips head machine screw  252  is passed through a hole  254  in the bolt tail  132  and is secured in a threaded opening  256  in the bottom of the channel  210  of the extension clip  200 . 
         [0053]    Although only a few exemplary embodiments have been shown and described in considerable detail herein, it should be understood by those skilled in the art that we do not intend to be limited to such embodiments since various modifications, omissions and additions may be made to the disclosed embodiments without materially departing from the novel teachings and advantages, particularly in light of the foregoing teachings. For example, although a cylindrical lock is shown, the novel extension clip shown and described herein may be used with any type of latchset or lockset for accommodating two or more backset distances. It is envisioned that a variety of extension clips and corresponding sleeves may be made to accommodate a variety of lock assemblies and backset dimensions not discussed in detail herein. Accordingly, we intend to cover all such modifications, omission, additions and equivalents as may be included within the spirit and scope as defined by the following claims. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures. Thus, although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to secure wooden parts together, whereas a screw employs a helical surface, in the environment of fastening wooden parts, a nail and a screw may be equivalent structures.