Patent Publication Number: US-7581421-B2

Title: Door lock assembly having a support structure to support a tailpiece and a retaining plate

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
   This application claims priority of Taiwanese Utility Model Patent Application No. 095217085, filed on Sep. 22, 2006. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates to a door lock assembly, more particularly to a door lock assembly having a retaining plate to removably hold a handle on a spindle tube. 
   2. Description of the Related Art 
   It is known to provide a door lock with a handle that carries a key-operated lock and that is connected to a spindle tube through which a latching device can be operated to latch or unlatch a door. Typically, the handle is connected removably to the spindle tube through a retaining plate that is disposed within the spindle tube and that is biased by a spring to interlock with a retention slot provided in the handle. The handle has a tubular body connected to the spindle tube and a longitudinal slot receiving a key-operated cylinder lock having a key plug connected to a tailpiece to operate the latching device. The retaining plate is disposed transversely in the longitudinal slot and is biased to project into the retention slot in the tubular body of the handle, thereby holding the handle on the spindle tube. When it is necessary to detach the handle from the spindle tube, the cylinder lock is first placed in an unlocking position, and a tool such as a pin is inserted into a tool hole formed in the tubular body of the handle to press the retaining plate so that the retaining plate is moved away from the retention slot and the handle can be removed from the spindle tube to replace the key-operated lock for re-keying. 
   Therefore, in order to prevent removal of the handle from the spindle tube against burglary, it is important that the retaining plate must be retained in the retention slot. In the conventional door lock, while the retaining plate can be kept in the retention slot through abutment with the tailpiece of the key-operated lock which is rotated to a locking position, due to the clearances that are likely to occur at the connection between the key plug and the tailpiece, the tailpiece can be swung to and fro by an external force and thus will be insufficient to rigidly support the retaining plate. Therefore, there is a likelihood incidence that the retaining plate may be removed undesirably from the retention slot by an external force when the key-operated lock is in the locking position. 
   U.S. Pat. No. 5,077,994 discloses a door lock having a lever handle that is removable from a rotary spindle for re-keying. The door lock includes a retaining plate  40  disposed transversely in a tubular body of a lever handle and is biased by a resilient block  70  that is disposed in a slot of the tubular body. The retaining plate has an aperture  48  and a downward lobe  50  projecting into the aperture. A lock tailpiece is connected to a plug  64  which is formed with a longitudinal groove  66  and which extends through the aperture. To rekey the door lock, the plug is rotated by a key to an angle (see  FIG. 3 ) so that the groove on the plug receives the lobe on the retaining plate when the retaining plate is pressed by a tool inserted into a retention slot in the tubular body. In  FIG. 2  of the patent, the lock tailpiece is in a locking state, and the retaining plate extends into the retention slot. Because the groove on the plug moves away from the lobe, and because the lobe can abut against the periphery of the plug when the retaining plate is pressed, the lever handle is prevented from being detached from the spindle tube against burglary when the door lock is in the locking position. 
   SUMMARY OF THE INVENTION 
   The object of the present invention is to provide a door lock assembly with a novel and simple support structure to support a tailpiece of a key-operated lock when the door lock assembly is in a locking state so that the tailpiece can sufficiently support a retaining plate to prevent a handle from being removed undesirably from the door lock assembly. 
   Accordingly, the present invention provides a door lock assembly which comprises: a handle having a tubular body provided with a radial retention slot; a spindle tube extending into the tubular body; a retaining plate disposed transversely inside the spindle tube, and having a retaining tongue projecting into the retention slot from the spindle tube, and a stabilizing part opposite to the retaining tongue; a spring biasing the retaining plate so that the retaining tongue projects into the retention slot; a support structure disposed within the tubular body oppositely of the retention slot, and having a support part extending radially into the spindle tube; and a lock unit mounted within the tubular body and having a key plug, and a tailpiece connected to the key plug and extending between the support part and the stabilizing part. The tailpiece has two diametrically opposite edges. When the lock unit is in a locking position and when the retaining tongue is pressed through the retention slot, one of the edges of the tailpiece abuts against the support part, and the other one of the edges abuts against the stabilizing part to prevent the retaining tongue from moving away from the retention slot. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiments of the invention, with reference to the accompanying drawings, in which: 
       FIG. 1  is an exploded view of a door lock assembly embodying the present invention; 
       FIG. 2  is a perspective view of a support structure of the door lock assembly; 
       FIG. 3  is a sectional view taken along a longitudinal plane extending longitudinally through a handle device and a spindle tube of the door lock assembly; 
       FIG. 4  is another sectional view taken along line  4 - 4  of  FIG. 3 ; 
       FIG. 5  is the same view as  FIG. 3  but showing a tailpiece in a first position thereof; 
       FIG. 6  is the same view as  FIG. 4  but showing the tailpiece in the first position; 
       FIG. 7  is the same view as  FIG. 3  but showing that a retaining plate is pressed inward; and 
       FIG. 8  shows another door lock assembly embodying the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Before the present invention is described in greater detail, it should be noted that same reference numerals have been used to denote like elements throughout the specification. 
   Referring to  FIGS. 1 and 2 , there is shown a door lock assembly including an outer handle device  1  embodying the present invention, a conventional inner handle device  6 , and a conventional latching device  7  operated by the outer and inner handle devices  1  and  6 . The outer handle device  1  generally includes a handle unit  2 , a support structure  3 , a lock unit  4 , and a spindle tube  5 . 
   The lock unit  4  is conventional, and includes a cylindrical case  401  receiving a key plug  43 , a tumbler case  402  connected to the cylindrical case  401 , and a tailpiece  41  connected integrally to the key plug  43 . The tailpiece  41  has two diametrically opposite edges  44  interconnecting two opposite faces  45 . The key plug  43  has a key slot  42  for insertion of a key (not shown). By operating the key plug  43  with the key, the tailpiece  41  is rotatable to a first position when the lock unit  4  is in a locking state, and a second position when the lock unit  4  is in an unlocking state. 
   Referring to  FIGS. 3 and 4  in combination with  FIG. 1 , the handle unit  2  includes a tubular body  21 , a handle  22  connected to the tubular body  21 . The tubular body  21  has an axial hole composed of a cylindrical hole portion  23  receiving the cylindrical case  401 , and a non-cylindrical hole portion  24  communicated with the cylindrical hole portion  23  and receiving the tumbler case  402 . A retention slot  25  is formed radially in the tubular body  21  in communication with the cylindrical hole portion  23 . 
   As is customary, the spindle tube  5  extends into the cylindrical hole portion  23  of the tubular body  21  and surrounds the tailpiece  41 . A conventional outer rose assembly  59  is connected to the spindle tube  5 . The spindle tube  5  further has a passage opening  570 , and a bounding edge that bounds the passage opening  570  and that includes two opposite axial edge parts  571  and a circumferential edge part  572  ( FIG. 3 ). 
   A retaining plate  51  is disposed transversely inside the spindle tube  5  and has a retaining tongue  53 . A spring  52  is disposed inside the spindle tube  5  to bias the retaining plate  51  so that the retaining tongue  53  projects out of the spindle tube  5  and extends into the retention slot  25 . The retaining plate  51  further has a stabilizing part  54  projecting inwardly in a direction towards said tail piece  41  and extending between two arms  56 . The two arms  56  project oppositely from the retaining tongue  53 , and extend on two sides of the tailpiece  41 . A spacing  561  is thus formed between the arms  56 . Two lugs  560  respectively project from the arms  56  in radial directions and into two slide slots  55  that are formed in the spindle tube  5  at two diametrically opposite positions. When the retaining plate  51  moves transversely inside the spindle tube  5 , the lugs  560  are slideable in the respective slide slots  55 . 
   The support structure  3  is disposed within the non-cylindrical hole portion  24  of the tubular body  21  and oppositely of the retention slot  25 . The tumbler case  402  is adjacent to the support structure  3 . The support structure  3  has a base part  30  disposed in the tubular body  21 , a support part  31  extending into the spindle tube  5 , a neck part  33  connected between the base part  30  and the support part  31  and passing through the passage opening  570  of the spindle tube  5 , and an engagement groove  32  formed between the base part  30  and the support part  31  and adjacent the neck part  33 . The support part  31  projects radially into the spacing  561  between the two arms  56  within the spindle tube  5 . Further, the support part  31  is opposite to the stabilizing part  54  of the retaining plate  51  so that the tailpiece  41  is between the support part  31  and the stabilizing part  54 . 
   The engagement groove  32  engages the axial edge parts  571  and the circumferential edge part  572  of the spindle tube  5  so that the support structure  3  is positioned firmly to the spindle tube  5 . However, the present invention should not be limited thereto. The engagement groove  32  may be arranged to engage one or two of the axial edge parts  571  and the circumferential edge part  572 . 
   Referring back to  FIGS. 3 and 4 , the tailpiece  41  is in the second position when the lock unit  4  is in the unlocking state, and the retaining tongue  53  of the retaining plate  51  extends into the retention slot  25  of the tubular body  21 . In this state, the edges  44  of the tailpiece  41  are away from the stabilizing part  54  of the retaining plate  51  and the support part  31  of the support structure  3 . Therefore, when a tool (not shown) or a narrow strip (not shown) is inserted into the retention slot  25  of the tubular body  25  to press the retaining tongue  53  against the spring  52 , the retaining tongue  53  is moved inward and away from the retention slot  25  so that the handle unit  1  can be detached from the spindle tube  5  for replacement of the lock unit  4 . 
   Referring to  FIGS. 5 and 6 , the tailpiece  41  is in the first position when the lock unit  4  is the locking state, and the retaining tongue  53  extends into the retention slot  25 . At this state, the edges  44  of the tailpiece  41  respectively move to the stabilizing part  54  of the retaining plate  51  and the support part  31  of the support structure  3 . If the tool or the narrow strip (not shown) is inserted into the retention slot  25  to press the retaining tongue  53  of the retaining plate  51 , the retaining tongue  53  cannot move out of the retention slot  25  because the support part  31  abuts against one of the edges  44  of the tailpiece  41  and the other edge  44  abuts against the stabilizing part  54  of the retaining plate  41 . As a result, the handle unit  1  cannot be detached from the spindle tube  5 , and the latching device  7  cannot be operated to unlock the door to which the latching device  7  is attached. 
   Referring to  FIG. 8 , there is shown another door lock assembly (B) having an outer handle device  1  embodying the present invention. Compared to the door lock assembly shown in  FIG. 1 , the door lock assembly (B) is of a different type that includes a latch operator spindle  9  that is inserted into the spindle tube  5  and that has a tab (not shown) connected to a latch operator or retractor  8 . The latch operator or retractor  8  is in turn connected to the latching device  7 . Aside from the types of the door lock assemblies shown in  FIGS. 1 and 8 , the present invention may also be embodied in other types of door lock assemblies. 
   While the present invention has been described in connection with what is considered the most practical and preferred embodiment, it is understood that this invention is not limited to the disclosed embodiments but is intended to cover various arrangements included within the spirit and scope of the broadest interpretations and equivalent arrangements.