Patent Publication Number: US-6708538-B1

Title: Doorknob lock apparatus operable by combination or key

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to door locking devices, and more particularly to a doorknob lock apparatus that is independently operable by dial entry of a combination or by a key. 
     2. Description of the Related Art 
     The need for reliable door locking systems for use at businesses and residences is widely recognized. It is also recognized that a lock capable of operation using a combination or a key offers versatility and convenience over common cylinder locks operable by key only. Consequently, efforts have been made to provide such a lock, as evidenced by prior art U.S. Pat. Nos. 3,353,383; 4,936,122; 5,113,675; and 5,475,996. 
     While perhaps suitable for specialized applications, the lock mechanisms described in the prior art generally require significant modification or replacement of the existing door and/or lockset. Even in prior art lock mechanisms that are capable of use with an existing lockset, installation is difficult and often requires cutting holes into the door, attaching mounting plates, installing wires, and performing other time consuming and costly steps. 
     Many electro-mechanical combination/key lock systems of the prior art, for example that of U.S. Pat. No. 4,936,122, require a battery power source having a finite lifetime, such that malfunction occurs when the battery is unable to properly energize the system. 
     BRIEF SUMMARY OF THE INVENTION 
     Accordingly, it is a principal object of the present invention to provide an improved convenient lock apparatus employing both key and combination actuating mechanisms by means of which the lock apparatus can be operated either by using a key or by entering the combination. 
     It is another object of the present invention to provide an improved lock apparatus that fits within the small volume allotted for prior art cylinder lock mechanisms. 
     It is yet another object of the present invention to provide a combination lock apparatus wherein the combination can be changed quickly and easily without disassembling the lock apparatus. 
     It is a further object of the present invention to provide a lock apparatus that is retrofittable or adaptable to a doorknob, deadbolt, locker, desk or the like. 
     It is a further object of the present invention to provide a lock apparatus wherein cam rings for combination operation are automatically scrambled before or as the lock apparatus is re-locked. 
     It is a further object of the present invention to provide an improved lock apparatus that avoids complicated and costly production and that is easy to assemble. 
     It is a further object of the present invention to provide a lock apparatus operable by combination or key wherein the combination cannot be determined from a key. 
     It is a further object of the present invention to provide an improved lock apparatus having an output nut for simple adaptation of the lock apparatus to an existing cylinder lock mechanism. 
     It is yet a further object of the present invention to accomplish the above objects in a completely mechanical lock apparatus that does not rely upon electrical devices requiring a power source. 
     In view of these and other objects that will become apparent to the reader, an improved lock apparatus of the present invention generally comprises a frame having an axially extending cylinder bore therethrough, a cylinder plug partially received by the cylinder bore having a keyhole, and a dial mounted coaxially about a front portion of the cylinder plug for combination entry. A front portion of the cylinder plug protrudes from the dial to form a knob, and an output nut is threadably mated with a rear end of the cylinder plug. A plurality of axially spaced detent wafers is slideably held within a plurality of respective radial slots in the cylinder plug, and each detent wafer is spring-biased to engage a primary keyway in the frame to prevent rotation of the cylinder plug relative to the frame. The arrangement defines a predetermined rotational reference orientation of the cylinder plug relative to the frame for maintaining a locked condition. The detent wafers are withdrawn from the primary keyway when a key is inserted in the keyhole, thereby allowing the cylinder plug to be rotated from its reference orientation. The cylinder plug rotation is transmitted through the output nut to move a locking member and achieve an unlocked condition. 
     The detent wafers are also withdrawn from the primary keyway by entry of a predetermined combination of numbers using the dial. The dial is operably connected to the wafers by a plurality of cam rings arranged about the frame, each cam ring having a cam surface for radially depressing an associated push pin communicating through the frame to one or more detent wafers. The dial rotationally drives a first cam ring adjacent thereto, and the first cam ring serves to drive a next adjacent cam ring, and so on, such that when the combination is entered in the correct manner the cam surface of each cam ring is in depressing engagement with an associated push pin to remove the plurality of detent wafers from the primary keyway. 
     A cam tube is provided about the cam rings and coupled by way of a ratchet mechanism to the cylinder plug so that the plurality of cam rings is in a scrambled state whenever the lock apparatus is re-locked. In the preferred embodiment, the cam tube includes an internal toothed portion adjacent its rear end, and a plurality of axially elongated slots angularly spaced about cam tube forward of the internal toothed portion. A plurality of spring plungers is mounted at angularly spaced intervals about the frame to engage toothed portion to provide suitable resistance to rotation of the cam tube relative to the frame. A carrier mounted on the cylinder plug supports a ratchet arm such that the carrier and ratchet arm rotate together with the cylinder plug. A free end of the ratchet arm operatively engages the internal toothed portion of the cam tube to rotate the cam tube with the cylinder plug in one rotational direction only. Each cam ring includes a spring plunger arranged to engage one of the plurality of slots in the cam tube upon alignment therewith to cause the cam rings to rotate with the cam tube and cylinder plug to scramble the cam rings either as the cylinder plug is rotated away from its reference orientation during unlocking or back to its reference orientation during relocking. 
     The lock apparatus preferably allows the combination to be easily changed without the need to disassemble the lock apparatus. Since the combination is determined by the specific driving orientation between the dial and first cam ring as defined by a drive pin coupling these parts, this driving orientation can be adjusted through axially directed separation against a spring bias and relative rotation between the dial and first cam ring to reset the drive pin within a different one of a plurality of angularly spaced drive holes in the coupled part. 
     The lock apparatus of the present invention is sized for incorporation or retrofit into a doorknob, deadbolt or other lock mechanism. For example, the lock apparatus of the present invention could be used in lockers, desks, or other settings. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     The nature and mode of operation of the present invention will now be more fully described in the following detailed description of the preferred embodiment taken with the accompanying drawing figures, in which: 
     FIG. 1 is a perspective view of a lock apparatus formed in accordance with a preferred embodiment of the present invention; 
     FIG. 2 is an exploded perspective view of the lock apparatus shown in FIG. 1; 
     FIG. 3 is an alternate exploded perspective view of the lock apparatus shown in FIG. 1; 
     FIG. 4 is a cross-sectional view of the lock apparatus taken generally along the line  4 — 4  in FIG. 1; 
     FIG. 5 is a cross-sectional view similar to that of FIG. 4, however showing the insertion of a key into the lock apparatus; 
     FIG. 6 is a partial front view taken generally along the line  6 — 6  in FIG. 5; 
     FIG. 7 is a cross-sectional view of the lock apparatus taken generally along the line  7 — 7  in FIG. 5; 
     FIG. 8 is a cross-sectional view of the lock apparatus taken generally along the line  8 — 8  in FIG. 4; 
     FIG. 9 is a cross-sectional view of the lock apparatus taken generally along the line  9 — 9  in FIG. 4, however showing operation of a third cam ring of the present invention during combination entry; 
     FIG. 10 is a side view of the lock apparatus, partially sectioned generally along the line  10 — 10  in FIG. 9, showing operation of the third cam ring; 
     FIG. 11 is a view similar to that of FIG. 10, however showing operation of a second cam ring of the present invention; 
     FIG. 12 is a view similar to that of FIG. 11, however showing operation of a first cam ring of the present invention; 
     FIG. 13 is a front view of the lock apparatus shown in FIG. 1; 
     FIG. 14 is a cross-sectional view of the lock apparatus taken generally along the line  14 — 14  in FIG. 12; 
     FIGS. 15-17 are a series of enlarged cross-sectional views showing operation of a ratchet of the present invention; 
     FIG. 18 is a view similar to that of FIG. 14, however showing a cylinder plug and ratchet arm carrier of the present invention rotated 90 degrees in a clockwise direction from a reference orientation; 
     FIG. 19 is an enlarged cross-sectional view taken generally along the line  19 — 19  in FIG. 12; 
     FIGS. 20 and 21 are a series of enlarged cross-sectional views similar to the view of FIG. 19, however showing rotation of a cam tube of the present invention; 
     FIG. 22 is a perspective view of the lock apparatus partially sectioned to show driving connection between a dial of the present invention and the first cam ring; 
     FIG. 23 is a cross-sectional view of the lock apparatus taken generally along the line  23 — 23  in FIG. 22; 
     FIG. 24 is a cross-sectional view of the lock apparatus taken generally along the line  24 — 24  in FIG. 22; 
     FIG. 25 is a view similar to that of FIG. 24 showing axially directed separation of the dial from the first cam ring for changing a combination of the lock apparatus; 
     FIG. 26 is a view similar to that of FIG. 24 showing axially directed return of the dial into driving connection with the first cam ring after the combination has been changed; 
     FIG. 27 is a perspective view of a lock apparatus of the present invention adapted for retrofitted installation into a doorknob; 
     FIG. 28 is a perspective view showing the lock apparatus of FIG. 27 installed in a doorknob; 
     FIG. 29 is a perspective view of a lock apparatus of the present invention adapted for retrofitted installation into a deadbolt lock; and 
     FIG. 30 is a perspective view showing the lock apparatus of FIG. 29 installed in a deadbolt lock. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Attention is directed initially to FIGS. 1-3 of the drawings, wherein a lock apparatus formed in accordance with a preferred embodiment of the present invention is shown and designated generally by the reference numeral  10 . Lock apparatus  10  comprises a frame  12  having a cylinder bore  14  extending in a direction of axis A through the frame, a cylinder plug  16  partially accommodated by cylinder bore  14  for enabling key operation of the lock apparatus, and a dial  18  mounted coaxially about a front portion of cylinder plug  16  for enabling combination operation of the lock apparatus. A portion of cylinder plug  16  protrudes from dial  18  to form a knob  19  that is preferably knurled or otherwise textured on its external circumferential surface to facilitate manipulation thereof. 
     Referring now to FIGS. 4 and 5 in addition to FIGS. 1-3, cylinder plug  16  includes a keyhole  20  opening through knob  19  into which a key  2  is received, and an output nut  22  is threadably or otherwise mated with a rear end of the cylinder plug. Detent means in the form of a plurality of axially spaced wafers  24 A- 24 F is provided for preventing rotation of cylinder plug  16  about axis A relative to frame  12 . More specifically, each wafer  24 A- 24 F is slideably held within a respective radial slot in cylinder plug  16  and biased by a spring  26  to engage a primary keyway  28  extending in an axial direction along cylinder bore  14  in frame  12 , and each wafer includes an opening  30  for receiving inserted key  2 . A secondary keyway  29  is provided opposite primary keyway  28  for temporarily accommodating ends of the wafers  24 A- 24 F as key  2  is inserted progressively through the wafer openings  30 . As can be understood, cylinder plug  16  normally resides in a predetermined rotational reference orientation relative to frame  12  when no key is inserted, and is securely kept in the reference orientation by the plurality of wafers  24 A- 24 F engaging primary keyway  28 . For example, in the present embodiment, the reference orientation can be thought of as ninety degrees based on the major axis orientation of elongated keyhole  20  of cylinder plug  16  as seen in FIG.  1 . 
     To operate lock apparatus  10  using key  2 , the key is simply inserted until all of the wafers  24 A- 24 F are forced by the key against the urging of springs  26  to withdraw the wafers from within keyways  28  and  29 , as shown in FIG.  5 . After all the wafers  24 A- 24 F have been withdrawn from keyways  28  and  29 , the user can grip the exposed end of key  2  and rotate the key, as shown in FIG. 6, to angularly displace cylinder plug  16  from the reference orientation. Rotational motion of the cylinder plug is imparted to output nut  22 , which is connected in a suitable manner to a locking member or bolt acting between the door and the doorframe, such that the locking member is moved to an unlocked position. Re-locking is accomplished by rotating the key and cylinder plug in an opposite angular direction to return the cylinder plug to its reference orientation. 
     Dial  18  is mounted coaxially about the front end of cylinder plug  16  that protrudes from frame  12 , and is independently rotatable about axis A relative to the cylinder plug and frame. Dial  18  is operably connected to detent wafers  24 A- 24 F by way of a plurality of cam rings  32 A,  32 B, and  32 C disposed about frame  12  and a plurality of associated  10  push pins  34 A,  34 B, and  34 C. A washer  31  is situated between dial  18  and first cam ring  32 A. The cam rings  32 - 32 C are spaced axially from one another by non-rotating spacers  35  between first cam ring  32 A and second cam ring  32 B, and between second cam ring  32 B and third cam ring  32 C, with spacers  35  being prevented from rotating by internal tabs  37  received within an external keyway  39  in frame  12 . Each cam ring includes an internal cam surface  36  for engaging an outer end of an associated push pin which is slidably mounted within a respective radially extending guide hole  33 A,  33 B or  33 C through frame  12 . An inner end of each push pin  34 A- 34 C is enlarged to bear against two adjacent wafers  24 A- 24 B,  24 C- 24 D, and  24 E- 24 F, respectively. Although the preferred embodiment described herein employs six wafers and three cam rings with three associated push pins each engaging two adjacent wafers, other arrangements are possible wherein the number of total wafers differs, and/or the number of wafers per cam ring and push pin differs. For example, an embodiment having four total wafers, four cam rings, and four push pins would fall under the scope of the present invention. 
     Dial  18  is connected to rotationally drive first cam ring  32 A by a drive pin  38  extending in an axial direction from a rear face of dial  18  for receipt within one of a plurality of angularly spaced drive holes  40  in an opposing front face of first cam ring  32 A. First cam ring  32 A includes a driver  42  protruding from a rear face thereof for engaging a corresponding follower  44  protruding from a front face of second cam ring  32 B. Likewise, second cam ring  32 B includes a driver  46  protruding from a rear face thereof for engaging a corresponding follower  48  protruding from a front face of third cam ring  32 C. 
     FIGS. 8-13 illustrate operation of lock apparatus  10  by entry of a predetermined combination of numbers using dial  18 . Combination entry is performed in a manner commonly known in connection with combination padlocks having a three-number combination. More specifically, dial  18  is rotated at least two complete revolutions in a clockwise direction and stopped when the first number of the combination is aligned with a fixed marker  4  on a doorknob or deadbolt casing (see FIGS.  28  and  30 ), or with an unmarked location such as a “twelve o&#39;clock” position. During this step, first cam ring  32 A is rotationally driven by dial  18  causing successive engagement of driver  42  with follower  44  and driver  46  with follower  48  to transmit rotational motion to third cam ring  32 C until cam surface  36  of third cam ring  32 C forces push pin  34 C downward as shown in FIGS. 9 and 10 to thereby remove wafers  24 E and  24 F from primary keyway  28 . Dial  18  is then rotated in a counterclockwise direction as indicated in FIG.  11  through one complete revolution and stopped when the second number of the combination is aligned with the fixed marker or location. This step causes driver  42  to come into reverse driving engagement with follower  44  on second cam ring  32 B to rotate the second cam ring in a counter-clockwise direction to a position wherein cam surface  36  of second cam ring  32 B forces push pin  34 B downward as shown in FIG. 11 to thereby remove wafers  24 C and  24 D from primary keyway  28 . The total degree of rotation is insufficient, however, to bring driver  46  into reverse driving engagement with follower  48 , thereby allowing third cam ring  32 C to remain in its previous orientation. Finally, dial  18  is rotated again in a clockwise direction until the third number of the combination is aligned with the fixed marker or location, thereby rotating first cam ring  32 A until its cam surface  36  forces push pin  34 A downward as shown in FIG. 12 to remove wafers  24 A and  24 B from primary keyway  28  without disturbing second cam ring  32 B or third cam ring  32 C. Once the combination has been entered, all of the detent wafers  24 A- 24 F are removed from engagement with primary keyway  28  and cylinder plug  16  can be rotated about axis A away from its reference orientation with respect to frame  12 . Such rotation of cylinder plug  16  can be in either rotational direction as illustrated in FIG. 13, and is accomplished without key  2  by manipulating knob  19 . 
     Lock apparatus  10  preferably comprises a mechanism whereby cam rings  32 A- 32 C are “scrambled” from depressing engagement with associated push pins  34 A- 32 C incident to rotation of cylinder plug  16  back to its reference position when a user locks the door. As will be appreciated from the following portion of the description, cam rings  32 - 32 C are scrambled regardless of whether the preceding unlocking of lock apparatus  10  was by key or by combination. Additional reference is now made to FIGS. 14-21 for describing the scrambling mechanism. Lock apparatus  10  comprises a cam tube  50  arranged coaxially about cam rings  32 - 32 C, frame  12 , and cylinder plug  16 . Cam tube  50  is secured by a snap ring  51  fitting within an annular groove in frame  12  to prevent axially directed movement of the cam tube relative to the frame. Cam tube  50  is provided with an internal toothed portion  52  adjacent its rear end, and a plurality of axially elongated slots  54  angularly spaced about cam tube  50  forward of internal toothed portion  52 . A plurality of spring plungers  56  is mounted at angularly spaced intervals about frame  12  to engage toothed portion  52 , thereby introducing suitable resistance to rotation of cam tube  50  relative to frame  12 . A carrier  58  has a proximal end mounted on a square cross-section portion  59  of cylinder plug  16  and a distal end which supports an elastically deformable ratchet arm  60  such that the carrier and ratchet arm rotate together with the cylinder plug about axis A. Ratchet arm  60  is fixed at one end thereof to the distal end of carrier  58 , and has a free end biased by a spring  62  for operative engagement with teeth  53  of internal toothed portion  52  of cam tube  50 . Depending upon the elastic deformation qualities of ratchet arm  60 , spring  62  may not be necessary. 
     It will be recalled that when a user unlocks and then re-locks a door by operating lock apparatus  10 , the user rotates cylinder plug  16  in one angular direction to unlock the door and then in an opposite angular direction to re-lock the door. For example, the user can rotate cylinder plug  16  in a clockwise direction as shown in FIG. 14 to unlock the door, and then in a counter-clockwise direction as shown in FIG. 18 to re-lock the door. During clockwise rotation of cylinder plug  16 , the free end of ratchet arm  60  is forced against the urging of spring  62  toward carrier  58  as it moves over each tooth  53 , and the cam tube  50  remains rotationally fixed relative to frame  12  by virtue of spring plungers  56 , as illustrated in FIGS. 15-17. Conversely, during counter-clockwise rotation of cylinder plug  16 , the free end of ratchet arm  60  engages a tooth  53  at an angle favorable to imparting sufficient torque to cam tube  50  to overcome the rotational resistance offered by spring plungers  56  such that the cam tube rotates together with the cylinder plug, carrier, and ratchet arm. As cam tube  50  rotates in the counter-clockwise direction in accordance with FIGS. 19-21, one of the plurality of slots  54  on the cam tube will become aligned with a plurality of spring plungers  64 A- 64 C respectively located on the exterior of cam rings  32 - 32 C opposite cam surface  36 . Spring plungers  64 A- 64 C are thus forced into engagement with the aligned slot  54 , and as a consequence cam rings  32 A- 32 C are rotated together with cam tube  50 , ratchet arm  60 , carrier  58 , and cylinder plug  16  until the cylinder plug is returned to its reference orientation. Ratchet arm  60  may of course be arranged in an opposite manner such that cam tube  50  and cam rings  32 - 32 C rotate clockwise with clockwise rotation of the cylinder plug. It will be appreciated that the cam rings are scrambled either as the user unlocks the door or as the user re-locks the door, depending upon the arrangement of ratchet arm  60  and the initial direction of rotation as the door is unlocked. It is also noted that elongated slots  54  are preferred recesses for receiving ball plungers  64 A- 64 C due to ease of manufacturing and thickness limitations in cam tube  50 , however such recesses could be in the form of individual through-holes for the respective ball plungers, individual non-through recesses in the internal wall of cam tube  50 , or non-through elongated recesses in the internal wall of cam tube  50 . 
     Another feature preferably incorporated into lock apparatus  10  enables the dial combination to be changed as desired. As seen in FIG. 22, dial  18  includes drive pin  38  extending in a rearward direction from the dial and received within one of a plurality of angularly spaced drive holes  40  provided in the front face of first cam ring  32 A. Depending upon which of the plurality of holes  40  receives drive pin  38 , a specific driving orientation is established between dial  18  and first cam ring  32 A which determines the combination numbers. Thus, to change the combination, dial  18  must be separated in an axial direction from first cam ring  32 A to withdraw drive pin  38  from within a drive hole  40 , dial  18  must be rotated relative to first cam ring  32 A, and then dial  18  and first cam ring  32 A must be moved together in an axial direction to insert drive pin  38  within a new drive hole  40 , thereby establishing a new drive orientation and a new combination. FIGS. 23-26 illustrate the structure and procedural steps in connection with changing the combination. As can be seen in FIG. 24, a front side of carrier  58  includes a protrusion  66 , and frame  12  includes a recess  68  in an annular face thereof opposite the front side of the carrier. Normally, protrusion  66  does not reside within recess  68  because carrier arm is not in a rotational position wherein the protrusion is aligned with the recess, and because a spring washer  70  mounted between frame  12  and output nut  22  urges output nut  22 , carrier  58 , cylinder plug  16 , and dial  18  axially to the right in FIG. 24 relative to frame  12 . The location of recess  68  is chosen such that cylinder plug  16  must be moved away from its reference orientation to bring protrusion  66  into alignment with recess  68 . In the embodiment presently described, cylinder plug  16  is rotated counter-clockwise until further rotation is prevented by engagement of carrier  58  with a horizontal surface  72  of frame  12 , approximately ninety degrees from the reference orientation as shown in FIG. 23, to bring protrusion  66  into alignment with recess  68 . Once alignment is achieved, the user is able to pull dial  18 , cylinder plug  16 , carrier  58 , and output nut  22  in an axial direction against the urging of spring washer  70  to the left as shown in FIG. 25 just enough to withdraw drive pin  38  from an existing drive hole  40 , thereby separating the driving connection between dial  18  and first cam ring  32 A. Dial  18  is then rotated relative to first cam ring  32 A to align drive pin  38  with a new drive hole  40 , and dial  18  is released. FIG. 26 shows dial  18 , cylinder plug  16 , carrier  58 , and output nut  22  being forced to the right by spring washer  70  upon completion of the combination change. It will be appreciated that the combination may only be changed by a person having either the key or knowledge of the combination. From a structural standpoint, the male/female mating between drive pin  38  and drive hole  40  may be reversed such that drive holes  40  are located on dial  18  and drive pin  38  is located on first cam ring  32 A. Likewise, protrusion  66  can be formed on frame  12  and recess  68  can be provided in carrier  58  to achieve the desired function. It is noted that knob  19  of cylinder plug  16  bears against a lip on frame  12  to provide an annular gap for an inner portion of dial  18  so that the dial is not pinched between the knob and frame by force from spring washer  70 . 
     FIGS. 27 and 28 show a manner of mounting lock apparatus  10  within a standard door knob  80  using spring clips  82 . A drive shaft  84  is connected to output nut  22  for transmitting rotational motion to a locking member or mechanism (not shown). FIGS. 29 and 30 show a manner of mounting lock apparatus  10  within a standard deadbolt casing  90  using fasteners  92 . A drive member  94  is connected to output nut  22  for transmitting rotational motion to a locking member or mechanism (not shown). Accordingly, the lock apparatus of the present invention is easily adapted for retrofit with an existing doorknob or deadbolt. Of course, the lock apparatus of the present invention can also be provided as part of a newly manufactured doorknob, deadbolt, locker door, desk drawer, file cabinet drawer, or other lock mechanism.