Abstract:
To provide lock servicing of particular door locks in common use, a bypass key (1) with key blade (2) long enough to reach through a lock-cylinder plug (26 and 45) and low enough to pass under extended tumblers (37) of a lock cylinder (28 and 43) in order to dislodge a tailpiece (36) from a stop-washer (63 and 45) or other attachment means at an inside end of the plug is provided in conjunction with a control key (14 and 21) with a key blade (13) of the same length into which single-lock and multiple-lock profiles (15) can be made to rotate the lock plug (26 and 45) and disengage or engage a lock cylinder (28 and 43) and its means of attachment to a door lock (54). Methods are provided for using the bypass keys (1, 1A, 18, 22 and 23) in conjunction with the control key (14 and 21) for unlocking a door (55) and installing a new or changed lock cylinder (28 and 43) without removing the lock (54) from the door (55), a time-consuming process that is required in current lock-change methods, regardless of whether or not a key for the lock is available.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to key blanks and more particularly to bypass keys and methods for using the bypass keys to change locks and to service particular types of door locks without removing the locks from the doors. 
     Previously in the lock-service industry, it has been necessary for locksmiths to remove entire locks from doors in order to change locks and otherwise to service most of the more widely-used door locks. In some of the currently popular door locks, there are inside keyless lock mechanisms referred to commonly as entry locks. They allow the door to be locked from one side, such as within a building or a room, without a key but require a key for unlocking the door from the opposite side or from outside the room or building. When a key has been lost or stolen, or when there is a new user of a lock, a particular user of the lock may want to prevent others who may have keys to the lock from unlocking or using it. This requires servicing of the lock by changing or replacing the lock cylinder to use a different key. 
     SUMMARY OF THE INVENTION 
     One object of this invention is to make it possible to remove a lock cylinder from a door without removing the entire door lock when a key has been lost or forgotten or for other reasons is not reasonably available. 
     Another object of this invention is to make it possible to install a new or a changed lock cylinder into a door without removing the lock from the door when a key to the lock is not readily available. 
     A further object of this invention is to make it possible when a key to a lock is available to install a new or changed lock cylinder in a door without removing the lock from the door. 
     Still another object of this invention, needed particularly for use in business establishments, apartments, hotels and condominiums, is to make it possible to install new or changed locks to a plurality of similar doors with similar locks whenever desired without removing the locks from the doors, regardless of whether or not a key is reasonably available. 
     The present invention accomplishes the above and other objects by providing lock servicing of particular door locks in common use, a bypass key with a key blade long enough to reach through a lock-cylinder plug and low enough to pass under extended tumblers of a lock cylinder in order to dislodge a lock shaft from a lock-ring or other attachment means at an inside end of the plug is provided in conjunction with a control key blank with a key blade of the same length into which single-lock and multiple-lock profiles can be made to rotate the lock plug and disengage or engage a lock cylinder and its means of attachment to a door lock. Methods are provided for using the bypass key in conjunction with the control key blank for unlocking a door, removing a lock cylinder from the door and installing a new or changed lock cylinder without removing the lock from the door, regardless of whether or not a key for the lock is available. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     This invention is described by claims in relation to a description of preferred embodiments illustrated in the following drawings in which: 
     FIG. 1 is a side view of a double-ward-cut bypass key before alteration of a blade tip for contacting a lock tailpiece; 
     FIG. 2 is a side view of a double-ward-cut control key blank; 
     FIG. 3 is a side view of a double-ward-cut control key that has been profiled for a particular lock and plurality of locks; 
     FIG. 4 is a side view of a double-ward-cut bypass key with a blade tip extended selectively upward for contacting a lock tailpiece; 
     FIG. 5 is a side view of a tumbler raiser tool with key bow having a tumbler-raiser peak at the blade tip; 
     FIG. 6 is a side view of a single-ward-cut bypass key before alteration of a blade tip for contacting a lock tailpiece; 
     FIG. 7 is a side view of a single-ward-cut control-key blank; 
     FIG. 8 is a side view of a single-ward-cut control key that has been profiled for a particular lock and plurality of locks; 
     FIG. 9 is a side view of a single-ward-cut bypass key with a blade tip extended selectively upward for contacting a lock tailpiece; 
     FIG. 10 is a rear view of a lock-cylinder assembly showing in particular a cylinder stop piece with an angular orifice through which a bypass-key blade is employed to dislodge a lock tailpiece; 
     FIG. 11 is a rear view of a lock-cylinder assembly at a housing retainer-ring section showing in particular a retainer inside diameter through which bypass keys must pass to reach a rear dislodgment section of a lock cylinder; 
     FIG. 12 is a front view of a lock-cylinder assembly illustrating in particular a keyway at a key-entry face of lock-cylinder plug; 
     FIG. 13 is a cutaway side view of a lock cylinder with a tumbler raiser tool having a tumbler-raiser peak at a tip of the blade inserted under the spring-loaded housing chambers and unsprung tumblers in a lock plug to raise the tumblers individually to a shear line, thereby allowing rotation of a cylinder plug with the help of a separate tool inserted at a keyway bottom in front of the plug; 
     FIG. 14 is a cutaway side view of a lock cylinder with a double-ward-cut control key in a position in which the bottom pins have been employed to raise the top pin tumblers to a line of contact of the plug and the housing (that is, the shear line) in order to allow rotation of the plug to operate the lock cylinder; 
     FIG. 15 is a rear view of a lock-cylinder assembly at a lock ring with an angular orifice through which a bypass-key blade is inserted to dislodge a lock tailpiece short variety of door locks for which single-ward-cut bypass keys are employed; 
     FIG. 16 is a rear view of a lock-cylinder assembly at a housing retainer-ring section showing in particular a retainer-ring inside diameter through which bypass keys must pass to reach a rear dislodgment section of a short variety of lock cylinders for which single-ward-cut bypass keys are employed; 
     FIG. 17 is a cutaway side view of a lock cylinder, after a tumbler raiser tool was used to raise bottom pins to shear line to turn cylinder plug, with a single-ward-cut bypass key with upwardly extended tip inserted under spring-loaded tumblers in a short variety of lock plugs; 
     FIG. 18 is a cutaway side view of a lock cylinder with a single-ward-cut control key in a position in which the control key has been used to raise spring-loaded tumblers to a line of contact of the plug and the housing (that is, the shear line) to allow rotation of a short variety of lock plugs to operate the lock cylinder; 
     FIG. 19 is a partial front cutaway view of door lock with a keyless inside lock in a door handle at the left side and a lock cylinder with a control key in operative position in an outside door handle at the right side. 
     FIG. 20 is an inside view of a door handle with lock cylinder removed for a door lock of a variety for which double-ward-cut bypass keys are used; and 
     FIG. 21 is an inside view of a door handle with lock cylinder removed for a door lock of a variety for which single-ward-cut bypass keys are used. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIG. 1, a bypass key 1 with a bypass key blade 2 is extended to a straight bypass-key tip 3 from a key bow 4 having selectively cut and positioned key shoulders 5. A base ward cut 6 and a tip ward cut 7 are provided in the vicinity of the tip 3 of a blade bottom 8. A flat bypass blade top 9, generally positioned slightly above a key groove 10, is low enough to pass under extended tumblers of a lock. 
     A series of bypass keys with double ward cuts 6 and 7 are provided for door locks with lock cylinders that are relatively long. 
     Referring to FIG. 2, a control key blank 11, the same length as the bypass key 1, is extended to a blank control key tip 12 from the key bow 4. A control key top 13 is the same height as a standard conventional key blank for a particular series of locks which either are sized and shaped to fit. Different from a conventional key blank, however, a control key blank 11 is provided with ward cuts 6 and 7 the same as the bypass key 1 and it is long enough to reach engagement and disengagement components of locks as described in relation to this invention. 
     Referring to FIG. 3, a control key 14 is in the form of a control key blank 11 that is provided with a top profile 15 which can be designed for a single lock or for a series of locks. 
     Referring to FIG. 4, an upwardly-extended tip 16 can be provided on a bypass key 1 for aiding contact with locking components of a lock as described hereafter. 
     Referring to FIG. 5, a tumbler-raiser tool 23 which is to be used in the opening procedure with the bypass keys is shown. 
     Referring to FIG. 6, a single-ward-cut bypass key 18 is generally shorter than the bypass key 1 because it is used for shorter lock plugs and requires only a single ward cut 19. However, it can be longer or as long as double-ward-cut keys for larger lock cylinders or for lock cylinders with more tumblers. For the single-ward-cut bypass key 18, there is only one or one group of obstacles for which a ward cut is required. Also, the tip 3 is shorter such that it does not require two ward cuts for the rigidity and material strength of the same tip 3 used on bypass key 1 shown in FIG. 1. 
     Referring to FIGS. 7-9, a single-ward cut 19 is provided for single-ward-cut control key blank 20, for single-ward-cut control key 21 and for single-ward-cut bypass key 22. Exclusive of shorter distances from shoulders to tips 12 and 16, and other features of this portion of the bypass key system are the same as for corresponding double-ward-cut keys for use with locks for which either may be sized and shaped to fit. 
     Referring to FIG. 10, a stop washer groove 24 with a cylinder stop aperture 25 is part of a lock-cylinder attachment means at an inward end of cylinder plug 26 which is rotatable in a cylinder face plate 27 in this rear view of a lock-cylinder assembly 28. Projecting vertically from the cylinder face plate 27 is a cylinder housing 29. It is an object of this invention to dislodge a locking member from the cylinder stop aperture 25 in locks which utilize this stop washer groove 24 as part of a means of attachment between a lock and a lock cylinder and as part of a locking means for various types of locks. 
     Referring to FIG. 11, a plug retainer ring 30 has a plug retainer ring groove 31 which is slightly inward from a keyway bottom 32 of a keyway 33 in the cylinder plug 26. It is to allow bypass keys 1, 1A, 11, 14, 18, 20, 21 and 22 to be inserted beyond this retainer ring 30 that a base ward cut 6 or a single ward cut 19 are provided. The keyway 33 is a form of channel which terminates at the cylinder face plate 27, such that the keyway bottom 32 is at an inside wall of cylinder face plate 27. 
     Now referring to FIG. 12 with reference to FIGS. 10 and 11, a cylinder plug face 35 at a front of lock-cylinder assembly 28 rotates inside of cylinder face plate 27 by rotation of a key in the keyway 33 when cylinder housing 29 is positioned with transverse motion arrested. Rotation of the cylinder plug 26 with a suitably profiled control key 14 or 21 and resulting rotation of a cylinder stop piece 34 allows engagement or disengagement of the lock-cylinder assembly and the lock in accordance with procedural steps described in this invention. 
     In FIG. 13, a tumbler raiser tool 23 with a tumbler-raiser tip 17 is inserted into a keyway 33 of a cylinder plug 26. The plug 26 is rotatable in a cylinder housing 29. In this cutaway side view, the plug retainer ring 30 is illustrated in a position to prevent outward travel of the plug 26 from the housing 27. In conjunction with use of a tension tool 67, commonly called a pick tool, the handle tailpiece 36 may be rotated. The handle tailpiece 36 normally is prevented from rotation by lock features not a part of this invention when it is positioned in the stop washer groove 24, thus preventing rotation of the cylinder from rotating an attachment means in the lock and from rotating the lock-cylinder assembly 28 to an engagement or disengagement relationship circumferentially in particular locks. In other locks, the attachment means is constructed differently but operates similarly in relation to this invention. Some features of locks not a part of this invention are illustrated to demonstrate a working relationship of parts of this invention to locks in which it is operable. 
     It is illustrated further in FIG. 13 that tumbler raiser blade 64 can pass under bottom pins 37 when the tip 17 is inserted to a position of contact with bottom pins 37. Not part of this invention but functioning in relationship to it are spring-loaded top pins 38 extending from spring-loaded tumbler chambers 39 in cylinder housing 29 into chamber wall 40 to prevent rotation of the cylinder plug 26 in cylinder housing 29. 
     Referring to FIG. 14, a control key 14 with ward cuts 6 and 7 and top profile 15 is inserted into keyway 33 to dislodgment contact with tailpiece 36. Different from insertion of bypass key 1, however, insertion of control key 14 positions the top profile 15 under bottom pins 41 which raise spring-loaded top pins 38 to a rotational line of contact (shear line) 42 of the plug 26 and the housing 29 to allow rotation of plug 26 and resulting operation of lock cylinder assembly 28. Rotation of the plug 26 with the tail piece 36 dislodged from stop washer groove 24 allows rotation of the cylinder stop piece 34 in FIGS. 10 and 11. When a control key 14 has been constructed for a particular lock or series of locks, then the bypass key 1 is not required. However, in servicing locks for which there is no key available as a pattern for copying a top profile 15 onto a control key blank 11 to for a control key 14, use of bypass key 1 is essential to this bypass key system. 
     Extended bottom pins 37, mentioned in relation to FIG. 13 and described further with reference to FIG. 14 above, are plug bottom pins 41 and spring-loaded top pins 38 which are in combined locking position. 
     Referring to FIGS. 15-18, a short-plug cylinder assembly 43 is illustrated in rear and side views in relationship to a single ward-cut bypass key 22 and control key 21. Form a front view, lock cylinder assemblies 28 and 43 are sufficiently the same that a front view of lock cylinder 43 is not shown. The rear sections are different, however, in ways that require different types of ward cuts and different lengths of keys generally. 
     Referring to FIGS. 15-18 and 21, flats 44 on single-ward-cut plug 45 are slidable through attachment orifice 46 in door-lock handle 47 when plug 45 is rotated to the same angle of rotation as attachment orifice 46. After plug 45 is inserted through orifice 46, plug 45 is then rotated to where opposite walls 48 of attachment orifice 46 are not at the same angle as the flats 44 in plug 45. This difference of angle of rotation causes a retainer wall 49 in lock base 50 to enter a retainer channel 51 at the base of flats 44 to secure lock base 50 to plug 45 and thus retain the lock cylinder 43 in single-ward-cut door-lock handle 47. Tumbler housing 29, extended from cylinder 43, is inserted into a housing channel 52 in a housing guide 53 which is attached to the lock base 50 to prevent housing 29 and the lock cylinder from which it extends from rotating when a key is rotated in the lock plug 45. When a conventional key is used, the lock rod 36 prevents the plug 45 from rotating to a position where the flats 44 are in line with opposite walls 48 of attachment orifice 46 and the lock cylinder 43 remains attached to lock base 50. However, when keys are made according to this invention are used, the lock rod 36 is dislodged and the plug 45 is allowed to rotate to where it can be removed from or installed in the lock handle 47. The lock components referenced are not part of this invention. However, they demonstrate how this invention is related to the lock components. 
     In FIG. 16, a plug retainer ring 30 serves the same function in relation to plug 45 as to plug 26 in FIGS. 10-14. There is a longer distance from the retainer ring 30 to a position of contact of the key 23 with a tailpiece 36. The orifices in differently-shaped plugs may be different in size also. These differences account for the single ward cut 19 in this bypass key system for different types of locks in which this invention is used. 
     Referring to FIGS. 19 and 20, an assembled door lock 54 in door 55 is provided with an inside handle 56 and an outside handle 57. A keyless lock mechanism often referred to as a night lock 58, is provided at the inside handle 56 while lock cylinder assembly 28 or 43 are operable with suitable conventional key at the outside handle 57. The night lock operates the tailpiece 36 in ways not a factor in relation to this invention. However, the existence and operation of the tailpiece 36 in ways not intended by its designers allow it to be used for assembling and disassembling either the lock cylinder assemblies 28 or 43 without removing them from the door with this invention. 
     The night lock can be a center-lug type or a door-handle type. A key-lockable inside lock with components operating in a similar manner in relationship to this bypass key system also can be employed within the scope of this invention. 
     It is emphasized that it is the bypass key system, not the lock or features of the lock that comprise this invention. Reference to the lock components are only incidental to describing the invention. This invention is made to service whatever type of lock from which a lock cylinder can be removed or installed in by extension of the key system through which the keyway to operate a lock-cylinder attachment means and locking mechanism. 
     In FIG. 20, a double-ward-cut door handle 59 is provided with a cylinder-housing channel 60 in door-lock sleeve 61 instead of the housing guide 53 and the lock base 50 in the single-ward-cut door handle 47. Arresting of transverse motion of the lock cylinder assembly 28 is achieved with the cylinder-housing channel 60 in a similar manner to that with which it is achieved with the housing guide 53. 
     Referring to FIGS. 20, 13 and 14, a cylinder assembly catch 62 at an inside wall of door-lock sleeve 61 is extended into a matching groove, channel or other matching attachment member such as a stop washer 63. Either attachment means can have an engagement path such as cylinder stop piece 34 and be operable by this key system. The handle tailpiece 36 extended through the center of the door handle can be a variety of angular shapes which match the cylinder stop aperture 25. 
     Change in the lock involving plug length, keyway width, keyway form, distance of locking components requiring ward cuts from keyway entry face, number of lock obstructions requiring ward cuts and other modifications of locks resulting in matching bypass-key-system modifications are anticipated and foreseeable within this invention. 
     All modifications, alternations, applications, forms and designs of this invention foreseeable from description in the following claims in light of the above specification and drawings are included in this invention, along with reserved, or restricted, or so called &#34;high security&#34; form types of locks.