Abstract:
A Removable Thumb Turn Attachment is disclosed. The device and system incorporate a thumb turn cap that is attachable to the head of a conventional deadbolt key. The system may include a retaining cap assembly that is installable over a conventional deadbolt lockset. The retaining cap assembly cooperates with the thumb turn cap so that the thumb turn cap will engage the retaining cap assembly so that the thumb turn cap, once inserted, cannot be readily removed from the retaining cap assembly. The thumb turn cap and retaining cap are installable on a conventional key-operated deadbolt lockset so that the lockset is converted to operate as a thumb-turn-operated deadbolt lockset.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     This invention relates generally to tamper-proof seals for containers and, more specifically, to a Removable Thumb Turn Attachment.  
         [0003]     2. Description of Related Art  
         [0004]     Deadbolt locksets are extremely common pieces of security equipment that can be found on virtually any entrance door found in a domicile. The deadbolt locksets are intended to back up the main lockset that is either knob, lever, or button-actuated, to provide a second level of lock security to entrance doors. The two common versions of deadbolt locksets are depicted in  FIGS. 1A and 1B .  FIG. 1A  is a perspective view of a conventional key-operated deadbolt lockset  10 A. The lockset  10 A has an exterior lock cylinder subassembly  12  (protruding on the outer side of the door  11 ) and an interior lock cylinder subassembly  14 A. On the key-operated type of lockset, the interior lock cylinder subassembly is actuated by a key  20  inserted into the key slot  18  and turned.  
         [0005]     The key-operated deadbolt lockset  10 A is intended to provide the most superior security to the occupant. If used as intended, the occupant will not keep the key  20  inserted into the key slot  18  on a regular basis, but rather will only insert the key  20  when actually locking the deadbolt. The key  20  should then be removed and placed away from the door  11 . If this process is followed, an intruder would not be able to break out a window within the door to reach the key  20  (that is still in the key slot), because the key  20  wouldn&#39;t be there.  
         [0006]     Unfortunately, the typical occupant does not follow this process, but rather leaves the key  20  inserted into the key slot  18  at all times for convenience. Furthermore, a truly crafty intruder could gain access to the domicile innocently, and then remove the key  20  from the deadbolt  10 A at an opportune moment. Now the intruder can return and gain entry to the domicile using the occupant&#39;s own key.  
         [0007]      FIG. 1B  is a perspective view of the other type of conventional deadbolt lock set—the thumb turn-operated lockset  10 B. Instead of having a key, this type of lockset  10 B has a permanently-attached thumb turn  22  or knob extending from the interior lock cylinder subassembly  14 B. The thumb turn  22  provides very convenient operation to the occupant, but is really only suitable for entry doors having no windows built into them, or in close proximity to the door. What is needed is a deadbolt actuating system that has the strengths of both the key-operated deadbolt lockset as well as the thumb turn-operated lockset. For reference later in this specification, the specific elements of the prior device will be more fully described herein.  
         [0008]      FIG. 2  is a side view of a conventional key-operated deadbolt lockset  10 A. The lockset  10 A, as discussed above, has an exterior lock cylinder subassembly  12  and an interior lock cylinder subassembly  14 . Both subassemblies  12  and  14  have key slots  18  formed within them for accepting the same key  20  for operating the lockset  10 A.  
         [0009]     The exterior lock cylinder subassembly  12  is substantially encased within a decorative and protective exterior collar  26 , typically conical in shape. The interior lock cylinder subassembly  14  is encased within a conical interior collar  24 .  
         [0010]      FIG. 3  is a front view of the key-operated deadbolt lockset  10 A of  FIGS. 1A and 2 . The interior collar  24  transitions into a substantially flat face  28  that is parallel to the interior surface of the door  11 . The key slot  18  is actually formed within the lock cylinder  30  (the part that turns when the lockset is locked or unlocked). The lock cylinder  30  protrudes through a hole formed in the face  28  so that the face  28  and collar  24  remain stationary while the key slot  18  and lock cylinder  30  rotate. Typically, the entire interior lock cylinder assembly  14 A is attached to the door  11  by a pair of decorative mounting screws  32  threaded through a pair of matching apertures formed in the face  28  of the collar  24 .  
       SUMMARY OF THE INVENTION  
       [0011]     In light of the aforementioned problems associated with the prior devices and systems, it is an object of the present invention to provide a Removable Thumb Turn Attachment. The device and system should incorporate a thumb turn cap that is attachable to the head of a conventional deadbolt key. The system may include a retaining cap assembly that is installable over a conventional deadbolt lockset. The retaining cap assembly should cooperate with the thumb turn cap so that the thumb turn cap will engage the retaining cap assembly so that the thumb turn cap, once inserted, cannot be readily removed from the retaining cap assembly. The thumb turn cap and retaining cap should be installable on a conventional key-operated deadbolt lockset so that the lockset is converted to operate as a thumb-turn-operated deadbolt lockset.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]     The objects and features of the present invention, which are believed to be novel, are set forth with particularity in the appended claims. The present invention, both as to its organization and manner of operation, together with further objects and advantages, may best be understood by reference to the following description, taken in connection with the accompanying drawings, of which:  
         [0013]      FIGS. 1A and 1B  are perspective views of two commonly-available versions of deadbolt locksets;  
         [0014]      FIG. 2  is a side view of a conventional key-operated deadbolt lockset;  
         [0015]      FIG. 3  is a front view of the interior lock cylinder subassembly of the lockset of  FIG. 2 ;  
         [0016]      FIG. 4  is a side view of the key-operated deadbolt lockset of  FIG. 2  having a preferred embodiment of the thumb turn conversion assembly of the present invention installed thereon;  
         [0017]      FIG. 5  is a perspective view of the retaining cap assembly of the assembly of  FIG. 4 ;  
         [0018]      FIGS. 6A and 6B  are perspective views of snap-in thumb turn cap of the assembly of  FIG. 4 ;  
         [0019]      FIG. 7  is a partial cutaway side view of the snap-in thumb turn cap of  FIGS. 6A and 6B ; and  
         [0020]      FIG. 8  is a partial exploded cutaway side view of the assembly of  FIG. 4 .  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0021]     The following description is provided to enable any person skilled in the art to make and use the invention and sets forth the best modes contemplated by the inventors of carrying out their invention. Various modifications, however, will remain readily apparent to those skilled in the art, since the generic principles of the present invention have been defined herein specifically to provide a Removable Thumb Turn Attachment.  
         [0022]     The present invention can best be understood by initial consideration of  FIG. 4 .  FIG. 4  is a side view of the key-operated deadbolt lockset of  FIG. 2  having a preferred embodiment of the thumb turn conversion assembly  40  of the present invention installed thereon. One substantial benefit of the present invention is that it is specifically configured to attach to a standard key-operated deadbolt lockset without the need for alteration of any of the components.  
         [0023]     The assembly  40  comprises two major components: The retaining cap assembly  42  and the snap-in thumb turn cap  44 . The retaining cap assembly  42  has a collar cap portion  45  which encapsulates the outer profile of the interior collar  24  of the lockset. The retaining cap assembly  42  has a retaining tube  46  extending inwardly from the face of the lockset such that the inner bore of the tube  46  is positioned over the key slot in the lockset.  
         [0024]     The second component of the assembly  40  is the snap-in thumb turn cap  44 . The cap  44  is designed to accept a standard deadbolt key  20  within it, such that the head of the key  20  is completely encapsulated within the knob  48  of the cap  44 . The keyed portion of the key  20  (and other critical portions of the cap  44 ) extend within the internal bore formed by the retaining tube  46 . As will be discussed more fully below, the assembly  42  and the cap  44  cooperate such that when the key  20  and portions of the cap  44  are engaged fully with the assembly  42  (and the key  20  with the lockset), the cap  44 /key  20  assembly will be restrained from being removed by the assembly  42  (which is attached to the door  11 ). As a result, a standard key-operated deadbolt lockset is converted into a thumb turn-operated lockset. The difference here is that (as will be discussed below) the cap  44 /key  20  is easily removable by a user having the proper tool and knowledge. As such, the thumb turn can be removed from the deadbolt lockset for added security. If we now turn to  FIG. 5 , we can examine one of the critical components of the assembly  40  of the present invention.  
         [0025]      FIG. 5  is a perspective view of the retaining cap assembly  42  of the assembly  40  of  FIG. 4 . The assembly  42  has a collar cap portion  45  is essentially a hollow conical shape having an opening on the door-facing side, and transitioning into a substantially flat face portion  48  enclosing its opposing side. The retaining tube  46  extends outwardly from the interior-facing surface of the face portion  48 , to form the side boundaries of a key bore  52 . The tube  46  is positioned so that it is centered over the cylinder and key slot of the lockset (see  FIG. 3 ), so that a key tip inserted into the key bore  52  can reach the key slot provided in the lockset. Furthermore, the distal edge of the tube  46  has a retaining lip  54  formed around its periphery. As will become clear below, the retaining lip  54  is provided to cooperate with a feature extending from the thumb turn cap  44  to prevent the thumb turn cap  44  from being withdrawn away from the retaining cap assembly  42  once the thumb turn cap  44  has been snapped in. The retaining tube  46  also has a release aperture  56  formed through its wall. The aforementioned engaging element on the thumb turn cap can be depressed by a tool inserted through the release aperture  46  (when the thumb turn cap is rotationally positioned properly so that the key can release from the cylinder).  
         [0026]     The face portion  48  further has a pair of screw apertures  50  formed through it. The screw apertures  50  are positioned so that they align with the mounting screws in the conventional deadbolt lockset (see  FIG. 3 ). The retaining cap assembly  42  has a pleasing aesthetic appearance, so that it will not detract from the appearance of the door and lockset. If we now turn to  FIGS. 6A and 6B , we can examine the elements of the other major component of the assembly  40  of the present invention.  
         [0027]      FIGS. 6A and 6B  are perspective views of snap-in thumb turn cap  44  of the assembly  40  of  FIG. 4 . The cap  44  has a knob  58  which has an ergonomic outer shape so that it is comfortably operable as well as being aesthetically pleasing. A stem  60  extends from the knob  58 . The outer circumference of the stem  60  is sized and shaped such that it will insert into the retaining bore (see  FIG. 5 ) when the key (having the cap  44  attached to it) is inserted into the lockset cylinder.  
         [0028]     The cap  44  has a key head slot  62  cut into it. The slot  62  is formed in the knob  58  and the stem  60 , and is sized to fit the typical sizes and shapes of heads of keys. A set screw  64  is threadedly engaged with the stem  60  so that it can be tightened down once a key head has been inserted into the slot  62  in order to securely bind the cap  44  to the key. On the opposing side of the stem  60 , a retaining finger  66  extends outwardly from the side of the stem  60 . In this version, the finger  66  is spring-biased outwardly through a hole formed in the outer wall of the stem  60 , but in other versions, the same function may be served by a ball-detent, or even a thin-walled, depressible “bump” formed in the wall of the stem  60 . In any case, the location of the retaining finger  66  cooperates with the release aperture in the retaining tube of the retaining cap assembly so that when the key/thumb turn cap  44  is inserted into the key slot, the retaining finger  66  and the release aperture are in alignment. Because of this cooperation, when the retaining finger  66  is snapped in under the retaining lip formed in the retaining tube, the only way that the key/thumb turn cap  44  can be removed is to turn the key until it is in the insert/remove position, with the retaining finger  66  aligned with the release aperture. A tool, such as a paperclip, can be inserted into the aperture in the retaining tube until it depresses the finger  66 . Once depressed until it releases from behind the retaining lip, the finger  66  will allow the key to be withdrawn from the key slot.  
         [0029]     In a simplified embodiment, the thumb turn cap  44  will not incorporate the retaining finger  66 , but will have the set screw  64  for securing the cap  44  to a key head. Without the retaining finger  66 , the key/cap will not be locked into the deadbolt, but it will serve to convert a conventional key-operated deadbolt to a thumb-turn-operated deadbolt. The stem  60  detail is more easily understood by review of  FIG. 7 .  
         [0030]      FIG. 7  is a partial cutaway side view of the snap-in thumb turn cap  44  of  FIGS. 6A and 6B . As shown here, the set screw  64  threadedly engages a threaded bore  68  formed in one side of the stem  60 . The set screw  64  can be turned until its tip engages the key inserted into the key head slot  62  formed between the two halves of the stem  60 .  
         [0031]     The retaining finger  66  in this version has a biasing member  70  in the sidewall of the other half of the stem  60 . The finger  66  is biased outwardly through the hole  72  formed in the side of the stem  60 . If we finally turn to  FIG. 8 , we can see how the two components of the assembly of the present invention interact.  
         [0032]      FIG. 8  is a partial exploded cutaway side view of the assembly  40  of  FIG. 4 . After removing the mounting screws from the interior lock cylinder subassembly  14 A, the retaining cap assembly  42  is placed over it, and the mounting screws are reinserted through the screw apertures ( 50 , see  FIG. 5 ), and into the face  28  of the subassembly  14 A, and tightened until the assembly  42  is securely attached to the subassembly  14 A.  
         [0033]     The key bore  52  is now positioned over the key slot  18 , so that the key  20  (held within the cap  44 ) can be inserted therein until the key is fully inserted into the lockset. When inserted, the retaining finger (not shown) will engage the retaining lip  54 , which will prevent the cap  44 /key  20  from being removed from the retaining tube  46 . When the user wishes to remove the cap  44 /key  20 , the knob  58  need simply be turned until the key  20  is in the upright (released) position, and the retaining finger (not shown) is aligned with the release aperture (not shown). A tool inserted through the release aperture (not shown) to depress the retaining finger (not shown) will release the retaining finger (not shown) from the lip  54 , and the key  20  will be removable.  
         [0034]     Those skilled in the art will appreciate that various adaptations and modifications of the just-described preferred embodiment can be configured without departing from the scope and spirit of the invention. Therefore, it is to be understood that, within the scope of the appended claims, the invention may be practiced other than as specifically described herein.