DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

[0043] In describing the preferred embodiment of the present invention, reference will be made herein to FIGS. 1 - 7 of the drawings in which like numerals refer to like features of the invention.

[0044] Referring to FIGS. 1 and 2 , the present invention includes a lock core 10 having two externally threaded bearings 12 , 14 on opposite sides. The lock core 10 includes a front opening 16 that receives a latch mechanism 18 including a latch bolt frame 20 formed in the shape of a tube. The latch mechanism 18 includes a latch bolt 22 and a retractor mechanism 102 (see FIGS. 6 and 7 ) located within the latch bolt frame 20 for retracting the latch bolt.

[0045] The tube comprising the latch bolt frame 20 extends through opening 16 in the front of the lock core 10 , across the centerline 24 , and into engagement with a second opening 26 in the back of the lock core (see FIG. 3 ). A lock pin 28 with an enlarged head 30 extends through the lock core 10 and through hole 32 in the back of the latch bolt frame to securely hold the latch mechanism 18 in the lock core 10 . FIG. 2 shows this assembled construction.

[0046] The axis 34 of the latch bolt mechanism and the axis 24 of the handles and lock core define a “T” shape. The latch bolt frame 20 rigidly engages the lock core 10 and extends outward from the cylindrical lock core to prevent rotation of the lock core 10 relative to the opening in the door in which it is installed. The lock core 10 is conventionally installed in an opening bored perpendicularly between the two faces of the door. The latch mechanism 18 is also installed in the conventional manner into a smaller hole drilled perpendicularly from the edge of the door into the larger opening.

[0047] Both the latch bolt frame and the lock core are ruggedly constructed. In particular, the tubular latch bolt frame cannot bend easily. Accordingly, the extension of the latch bolt frame out of the lock core, the rugged construction, and the extension of the latch bolt frame entirely through the lock core into pinned engagement with the back of the lock core, all cooperate to create a compact connection between the door and the lock mechanism. This arrangement makes the lock core highly resistant to rotation within the door and allows the forces applied to the lock mechanism during abuse to be transferred from the handle to the lock core and from there directly to the door. This eliminates the need for separate through-bolts, which are normally used in high quality lever handle locks to resist the abusive forces that can be applied to the lever handle.

[0048] The outside handle 36 is mounted on the shaft portion 38 of a sleeve 40 . An inner portion 32 of sleeve 40 rotates inside bearing 12 (see FIG. 3 ). The inner portion 42 and the shaft portion 38 of the sleeve 40 are separated by an enlarged portion 44 , which has a diameter greater than the inside diameter of bearing 12 .

[0049] The inner portion 32 slides into its bearing 12 until the enlarged portion 44 contacts face surface 46 of the bearing 12 . The sleeve 40 is held in its bearing 12 by an outside retaining collar 48 .

[0050] The outside retaining collar is threaded internally so it can be threaded onto the external threads of bearing 12 . The outside retaining collar 48 holds the enlarged portion 44 of the sleeve 40 in rotational contact with the face surface 46 of bearing 12 . Retaining collar 48 is provided with external threads (as well as internal threads) so that rose 50 (which is internally threaded) can be threaded onto its exterior. Outside collar 48 is provided with flats 52 so that it can be tightened with a wrench without damaging the external threads. The collar is tightened sufficiently to hold sleeve 40 with the desired pressure against the face surface 46 of bearing 12 . This design completely eliminates axial motion of the sleeve 40 relative to the lock core 10 .

[0051] The outer handle 36 is held to the shaft portion 38 of sleeve 40 by a setscrew 54 and by a spring retaining mechanism 56 . The spring retaining mechanism 56 cooperates with the lock cylinder 58 to prevent the handle 36 from being removed if key 60 is not inserted into the lock cylinder and turned. Setscrew 54 prevents the handle 36 from moving axially relative to the shaft portion 38 . The setscrew eliminates endplay between the handle 36 and the lock core 10 , providing a quality feel for the lock mechanism. The spring retaining mechanism 56 and the lock cylinder 58 cooperate to prevent the lever handle 36 from being removed without the key.

[0052] The inner side of the door is similar, and includes an inner sleeve 62 having an inner sleeve portion 64 , an enlarged portion 66 and an inner portion 68 that fits inside of bearing 14 . An inner collar 70 is internally threaded to engage the external threads on bearing 14 and is externally threaded to receive inner rose 72 . Inner handle 74 fits over shaft portion 64 of inner sleeve 62 . Setscrew 75 threads into inner handle 74 to hold the inner handle on the inner sleeve 62 and eliminate endplay.

[0053] In a conventional design, the lock core comes pre-assembled with the inner and outer shafts. The outer shaft must always be located on the locked side of the door. Accordingly, a conventional lock core is not symmetrical about a vertical plane through the center of the lock between the two halves. However, conventional designs are substantially symmetrical about the horizontal plane through the center of the lock. The horizontal symmetry allows the lock core to be flipped top for bottom for installation in either a right hand swing or a left hand swing door. This symmetry is important in producing a single lock that can be installed in both right-hand and left-hand swing doors.

[0054] The present invention, however, differs significantly. It is designed so that the lock core 10 is not symmetrical about the horizontal plane, but, instead, is substantially symmetrical about the vertical plane. To change the present lock mechanism for right-hand or left-hand installation, the lock core 10 is rotated about its vertical axis, instead of the horizontal axis. In a prior art design, this rotation would change the inside and outside of the lock because the inside and outside are fixed relative to the lock core.

[0055] To prevent this reversal in the present design, the inner sleeve 62 and outer sleeve 40 are removable. The inside and outside of the lock mechanism can be reversed by removing the collars 48 and 70 and their associated sleeves 40 , 62 to which the inner and outer handles are attached. This change in basic symmetry from the horizontal plane of the prior art to the vertical plane allows the stops for the handles to be located inside the lock core, instead of in the rose, while retaining the feature that the rest position of the handles is slightly upwardly elevated. As can be seen best in FIG. 4 , the lock core 10 , and the stops inside the core which define the rest position of the handles, are rotated slightly relative to the centerline 34 of the latch mechanism 18 such that the centerlines of the lever handles 36 and 74 are angled upward relative to horizontal by the angle θ, which is preferably about one or two degrees, and most preferably less than three degrees. Unlike prior art designs, in the present invention it is the lock core which defines the angular mounting orientation of the lever handle when it is at its rest position. The angle between centerline 34 of the latch bolt frame where it enters the lock core and the centerline of the lever handles is less than 180 degrees by the small angle θ.

[0056] The lock core 10 is always installed with the same surface at the top regardless of whether it is installed in a right hand swing or a left hand swing door. The inner and outer handles, roses, collars and sleeves can be installed on either side of the lock core to make either side the outside.

[0057] When the lock mechanism is unlocked, rotating lever handle 36 rotates sleeve 40 . As can be seen in FIG. 3 , sleeve 40 includes slot 80 , which extends perpendicularly across inner portion 42 of the sleeve. Slot 80 receives lugs 82 and 84 on locking piece 86 . The lugs project outwardly from the sleeve 40 and are guided by slot 80 .

[0058] The slot 80 allows locking piece 86 to slide axially inside the sleeve 40 between a locked position and an unlocked position. The locked position for the locking piece positions the locking piece close to handle 36 . In the unlocked position, locking piece 86 is located at the far end of the sleeve 40 from the handle 36 .

[0059] Because sleeve 40 cannot turn relative to the handle 36 , rotation of the handle always rotates locking piece 86 . Locking piece 86 includes an internally splined central opening 88 that engages externally splined portion 90 on spline member 92 . Spline member 92 fits inside the shaft portion 38 of sleeve 40 and engages splined opening 88 inside locking piece 86 . It is held in position by C-ring 94 , which fits into ring groove 96 . The splined portion 98 extends outward beyond the end of locking piece 86 to engage a corresponding splined opening 100 (see FIGS. 6 and 7 ) to operate retractor mechanism 102 inside the latch mechanism 18 . Splined portions 90 and 98 form a single piece comprising a latch driver that always moves and rotates with locking piece 86 . Extending through the center of these two splined portions 90 , 98 , however, is a shaft connecting key end 104 to splined end 106 . These two ends comprise a single key driven piece that always moves axially with the latch driver piece and the locking piece 86 . However, the key driven piece is free to rotate as a unit relative to the locking piece and to the latch driver. Key end 104 is driven by cylinder lock 108 through connecting piece 110 and the key tailpiece 111 . When key end 104 is rotated, splined end 106 is also turned.

[0060] When the locking piece 86 is in the locked position, splined portion 98 engages splined opening 100 in the retractor mechanism so that rotation of the handle will operate the retractor mechanism. When the locking piece 86 moves outward to the locked position, splined portion 98 is withdrawn from splined opening 100 . In this position, only splined end 106 engages the splined opening 100 and the latch may be retracted by rotating key 112 .

[0061] The axial motion of locking piece 86 between the inward (unlocked) position and the outward (locked) position causes the locking lugs 82 and 84 to engage and disengage the corresponding locking lug slots 114 , 116 .

[0062] From the description above, the complete locking action can now be described. The lock mechanism is locked by sliding the locking piece 86 outward to the locked position. The locking piece can be moved to this position from the outside of the lock by the lock cylinder 108 and key 112 or from the inside by the button mechanism 117 . As the locking piece moves outward, it simultaneously disengages splined portion 98 from the splined opening 100 in the retractor and moves the two heavy-duty locking lugs into engagement with the locking lug slots 114 , 116 in the lock core. Thus the locking lugs connect the lever handle 36 to the lock core, so that the rugged “T” design can prevent rotation as the handle is disengaged from the retractor.

[0063] As can be seen in FIG. 3 , the lock core 10 includes a center core piece 118 and two bearing caps 120 , 122 , which incorporate bearings 12 and 14 respectively.

[0064] The bearing caps 120 , 122 are held on the center core 118 with screws 124 . There are preferably four screws on each bearing cap. Unlike conventional lock designs, which are not easily disassembled or repaired in the field, by removing the screws, the lock core of the present design can be almost completely disassembled.

[0065] The outer bearing cap 120 encloses a pair of springs 130 , 132 and a spring driver 134 . The outer bearing cap 120 is shown in detail in FIG. 5 . The spring driver includes two inwardly directed fingers 136 , 138 , which engage corresponding notches on the outer sleeve 40 . Finger 136 engages notch 140 on sleeve 40 so that rotation of the handle 36 also rotates spring driver 134 .

[0066] Spring driver 134 also includes a pair of axially extending tabs 142 and 144 , which drive coil springs 130 and 132 . The coil springs 130 and 132 lie in channels formed in the inside perimeter of each bearing cap and are trapped between two corresponding spring stops 150 , 152 (see FIG. 5 ). The spring stops are located at the top and bottom inside the bearing caps. The springs 130 , 132 exert a force between the spring stops 150 , 152 and the tabs 142 , 144 on the spring driver to bring the tabs into alignment with the spring stops.

[0067] Rotation of the spring driver 134 in either direction will compress springs 130 and 132 between a spring stop at one end and a tab at the other end. Thus, the location of the spring stops defines the rest position of the handles. The positions of the spring stops and the rest position of the handles relative to horizontal and the axis 34 of the latch mechanism 18 are set during manufacture by the angle at which the bearing caps are installed on the center core piece 118 before the screws 124 are installed.

[0068] In addition to the spring stops, which define the rest position, the bearing caps define and limit the maximum rotation of the lever handles. Preferably this maximum rotation is about 45 degrees up and 45 degrees down. The limit stops are provided by two limit channels 156 , 158 machined into the inside of the bearing caps. The limit channels 156 , 158 are immediately adjacent to the locking lug slots 114 , 116 . When the locking piece moves inward to the unlocked position, the locking lugs 82 , 84 move out of the locking lug slots 114 , 116 and into the adjacent limit channels 156 , 158 . The channels are sized to permit the lever handles and locking piece to rotate the desired amount. If an attempt is made to rotate the handles beyond the maximum permitted rotation, the locking lugs contact the ends of the limit channels. Any excess force applied at this limit is transferred to the lock core and from there to the door through the “T” design of the lock. This protects the internal lock mechanism from excess force applied in the unlocked position as well as in the locked position.

[0069] A substantially identical arrangement is found within the opposite bearing cap 122 , which includes a corresponding spring driver and pair of coil springs. It will be understood from this description that the lock core includes the stops and the spring return mechanism necessary for the return of the lever handles 36 and 74 to the rest position on the stops. It can also be seen that when the lock mechanism is locked, by sliding lock piece 86 towards handle 36 , the locking lugs 82 and 84 engage bearing cap 120 . Locking lugs 82 and 84 also act against stops in the interior of the lock core.

[0070] This mechanism is unlike prior art designs in that the stops and the spring return mechanism are completely located within the lock core and not within the rose assemblies 50 or 72 . The locking mechanism is extremely robust because the locking lugs 82 and 84 project outward from the sleeve into contact with the bearing cap. Thus, the force resisting rotation is transferred through a heavy-duty machined sleeve to a heavy-duty, two lug, locking piece and from there to the lock core. The transfer of force from the locking piece to the core is done at the outer perimeter relative to the sleeve 40 . Because the locking lugs project out from the perimeter of sleeve 40 , the force on the locking mechanism is reduced as compared to prior art designs that locate the locking mechanism entirely within the rollup spindle, which roughly corresponds to the sleeves 40 , 62 of the present design.

[0071] The rotation of the lock core 10 within the door is resisted by the “T” design of the latch bolt frame 20 which extends completely through the lock core. The combination of heavy-duty lock core, “T” design and locking lugs that transfer force at a relatively large distance from the centerline of the lock produces a very secure locking mechanism, which is extremely resistant to abuse. The locking mechanism will easily resist the application of 1000 inch pounds of torque to the sleeve by the lever handle without damage. Torque in excess of this will not cause the lock to open. Consequently, it is not necessary to provide through-bolts from the rose 50 to the rose 72 , which pass outside the outer perimeter of the opening receiving the lock core 10 . Because through-holes and through-bolts are not required, the roses 50 , 72 can be thin and have a small diameter. This produces an attractive lock mechanism design, as compared to prior art designs which incorporate the spring return mechanism and through-bolts in the rose.

[0072] The outer components of the lock, including the outer handle 36 and lock cylinder 58 are mounted on the outer sleeve 40 . To prevent these components from being removed by removing the collar 48 , the outer collar 48 is produced with one or more sets of locking notches 146 and corresponding oppositely directed locking tabs 148 that produce a castellated edge on the outer collar 48 where it abuts the surface of the outer bearing cap 120 . The locking notches are sufficiently deep to receive the head 30 of the locking pin 28 .

[0073] The shaft of the locking pin is slightly longer than the width of the assembled lock core 10 . Because the inner collar 70 does not include the castellated edge, when it is installed, it forces the head 30 of the locking pin 28 to protrude up from the surface of the outer bearing cap 120 . That surface has a recess that initially allows the head 30 of the locking pin 28 to lie just below the plane of the surface where the outer collar 48 will abut it.

[0074] To assemble the mechanism, the lock core 10 is inserted into its opening in the door. It is important that the lock core 10 be inserted with its correct side to the top so that the stops are oriented to produce the desired slight upward angle for the handles when they are at the rest position. The latch mechanism 18 is then inserted into its opening in the door and pushed into opening 16 in the lock core and though to the back side, where it is seated in the second opening 26 in the back of the lock core. Pin 28 is then pushed into the lock core from the outer side of the door and through the back of the latch bolt frame 20 to lock it into place.

[0075] Pin 28 is pushed inward until the head 30 lies below the surface of the outer bearing cap 120 . Because either side of the door may become the locked side, both sides of the lock core 10 are provided with a recess to receive the head 30 of the pin 28 .

[0076] The outer sleeve 40 is then inserted into the outer bearing, i.e., on the same side as the head 30 of the pin 28 . The bearings 12 and 14 are identical, and both will accept either locking collar, depending on whether a right or left-hand swing door is desired. Next, the outer collar 48 is threaded on and tightened until locking tabs 148 contact the surface of the outer bearing cap 120 . The tabs can pass over the head 30 because it lies below the surface. Once the outer collar is tightened, the inner sleeve 62 is installed in the remaining bearing. As the inner collar 70 is tightened, it contacts the end of pin 28 and pushes the head 30 up out of its recess and into locking engagement with locking notch 146 in the castellated edge of the outer collar. This prevents the outer collar from being removed.

[0077] The outer and inner roses 50 and 72 are then attached, followed by the handles. Last, the setscrews 54 , 75 are tightened to completely eliminate endplay. A conventional knob handle is normally designed to retract the latch bolt with a rotation greater than 45 degrees. The present invention will also operate with such greater rotation angles by increasing the angular size of the limit channels. A greater rotation angle is comfortable for the user when grasping a round knob and rotating it by rotating the wrist. However, the motion of the hand when operating a lever handle is different and it is not comfortable for a user to have to rotate a lever handle with a rotation angle much greater than 45 degrees.

[0078] This lesser angle means that the retraction mechanism must retract the latch bolt more rapidly, i.e., retract it farther per degree of handle rotation, than is required for a knob handle. In the present invention, this requirement is met by a latch retraction amplifier in the latch bolt.

[0079] Referring to FIGS. 6 and 7 , the retractor mechanism 102 comprises a conventional cam 160 having splined opening 100 . As in prior art designs, a corresponding second cam and second splined opening are also located within the latch mechanism 18 symmetrically adjacent to the first cam 160 and the first splined opening 100 so that the inner and outer handles can independently retract the latch bolt. When the lever handle 36 is turned, splined portion 98 rotates the cam 160 from the position seen in FIG. 6 to the position seen in FIG. 7 . The cam 160 acts upon the tail 162 of the latch bolt 22 to retract it. In a conventional design, this retraction is direct, with the latch bolt head retracting the same distance as the latch bolt tail is moved. However, in the present design, the linear retraction motion of the head is amplified (as compared to the linear retraction motion of the tail) by retractor arm 164 .

[0080] The latch bolt head 22 includes a shaft 166 , which slides in plate 168 of the tailpiece 162 . Conventional springs (not shown) keep the latch bolt head extended (as in FIG. 6 ) relative to the tailpiece 162 . These springs and the motion of the head 22 relative to the tail 162 are well known and are needed to allow the latch bolt head 22 to move inward toward the retracted position, as the door swings closed and the latch bolt strikes the door frame, without requiring the handle to move.

[0081] In the present invention, during retraction of the latch bolt by the handle, the head and tail do not move as a unit, as in prior art designs. Instead, the retractor arm and a retractor link 170 are interposed between the head and tail portions of the latch bolt. The retractor link 170 is connected between the latch bolt tailpiece 162 and the retractor arm 164 . The retractor link 170 is connected to the latch bolt tailpiece 162 with pivot 172 and to the retractor arm 164 with pivot 174 .

[0082] The retractor arm 1 64 is connected to the stationary latch bolt frame 20 with pivot 176 . The tip 180 of the retractor arm 164 fits inside of slot 182 in the shaft 166 . Because the tip 180 of the retractor arm is farther from the fixed pivot 176 than the moving pivot 174 is from the fixed pivot 176 , the retraction motion of the tail 162 is amplified and the shaft 166 and head of the latch bolt 22 move to the fully retracted position with significantly less angular rotation of the cam 160 than is required in prior art devices. The retractor link acts upon the retractor arm to amplify the linear motion of the latch rod such that the latch bolt moves to the completely retracted position when the lever handle is rotated by no more than forty-five degrees.

[0083] While the present invention has been particularly described, in conjunction with a specific preferred embodiment, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. It is therefore contemplated that the appended claims will embrace any such alternatives, modifications and variations as falling within the true scope and spirit of the present invention.