Lock with flat tumblers and changeable code

Abstract: A lock with flat tumblers and changeable code comprises tumblers which are composed of two parts (15,14) which have mutually opposite sets of teeth (30,31) which are adapted to mutually mesh according to a preset code. The code is changed by mutually spacing the sets of teeth with a suitable tool (85) and by restoring their meshing according to the code of a new key.

Description: The present invention relates to a lock with flat tumblers and changeable code. Locks with flat tumblers and changeable code are known in the art and in particular, a lock of this type is disclosed in Italian patent no. 1264745 in the name of the same Applicant. However, changing the code in this lock is troublesome, since a code-changing key is required which cannot be easily managed by all of the users. The aim of the present invention is to provide a lock with flat tumblers and changeable code with which code changing is considerably simplified with respect to conventional locks. This aim is achieved with a lock with flat tumblers and changeable code whose characteristics are defined in the appended claims. Further advantages and characteristics will become apparent from the following description of an embodiment of the lock according to the invention, illustrated by way of non-limitative example in the accompanying drawings, wherein: Figure 1 is a partially sectional view of the lock in the closed condition; Figure 2 is a partial sectional view, taken along the plane II-II of Figure 1; Figure 3 is a partially sectional view of the lock in the code changing position; Figure 4 is a partial sectional view, taken along the plane IV-IV of Figure 3; Figures 5 and 6 are views of a detail of the lock in two operating positions; Figure 7 is an enlarged-scale view of a flat tumbler; and Figure 8 is a sectional view, taken along the plane VIII-VIII of Figure 7. With reference to the above figures, the reference numeral 1 designates the faceplate of the casing of a lock, which also comprises the bottom 2, which is surrounded by a peripheral wall composed of the walls 3, 4 and 5, which with reference to the drawing and for the sake of convenience in description are termed upper wall, rear wall and lower wall, respectively. The reference numeral 6 designates the cover for closing the casing. A plurality of circular openings 7 are formed in the faceplate 1; a plurality of cylindrical pins protrude externally through openings 7 and form a bolt 8 which is slideable in the direction A and is fixed to a tang 9 which lies inside the casing. The tang 9 is constituted by a flat bar which is thinner than the bolt 8, which is assumed to lie on the centerline plane of the casing. The tang 9 has, along its lower edge, a plurality of teeth 10 which form a rack on which the bolt actuation key acts. A slot 11 is formed in the tang 9 and is elongated in the direction A; a threaded bush 12 engages in slot 11 and rises from the bottom 2 of the casing to which it is fixed. The bush 12, together with the bolt 8, allows to guide the tang 9 during its sliding, and a screw is screwed therein. The cover 6 is fixed by means of said screw so as to close the casing of the lock. An equal number of flat tumblers is arranged on either side of the tang 9; one of the tumblers, generally designated by the reference numeral 13, is shown more clearly in Figure 7. For the sake of illustration, the total number of tumblers is assumed to be six, divided into two groups of three adjacent tumblers. One group is on one side of the tang 9 and the other group is on the opposite side. Each tumbler 13 is composed of a rectangular part 14 and of a part 15 which has a composite shape. The part 14 is termed changing strip hereinafter owing to its code-changing function, as described hereinafter, while the part 15 is termed retainer lamina in relation to its ability to prevent the sliding of the bolt 8. During code changing, the strip 14 (see Figure 7) is provided with two slots 16 and 17 which are elongated in the direction B at right angles to the direction A and with a lower end 18 which is shaped so that it can be engaged by the profile of a double-pattern key 19 which, inserted through an opening 20 of the bottom 2 or of the cover 6 of the casing, lifts the strip 14 in the direction B. One edge of the strip 14 is straight and parallel to the slots 16 and 17 and has a set of teeth 21 which is adapted to mesh with a set of teeth 22 formed on a contiguous edge of the lamina 15. The lamina 15 comprises a central portion 23 which is rectangular and elongated in the direction A and from which two rectangular wings 24 and 25 protrude upwards and downwards; slots 26 and 27 are formed in wings 24,25 and are elongated in a direction which is parallel to the slots 16 and 17. The slots 26 and 27 are engaged by the bush 12 and by an additional bush 28, so that the laminae 15 are only movable in the direction B. In the central portion 23 of each lamina 15 there is an opening 29 which is elongated in the direction A and from the upper longitudinal edge of which there protrudes a series of teeth 30 which, together with a second series of mutually opposite teeth 31 which protrude from the lower edge of the opening 29, form the code of the lock. The teeth 30 form tooth spaces which have a square shape and are such as to allow the engagement, between said teeth, of a pivot 32 which has a square cross-section and protrudes from both sides of the tang 9, with which it is rigidly coupled. The teeth 30 of each tumbler have alternating identical heights which are nonetheless different from the height of the teeth of the adjacent tumbler. Furthermore, the mutually opposite ends of the upper teeth 30 and of the lower teeth 31 delimit a passage which allows the square pivot 32 to pass between the mutually opposite teeth when the tumblers are actuated by the key 19. The lamina is completed by two notches 33 and 34, which are formed on the edge of the wing 25 that is directed toward the rear wall 4 and at the end of the opening 29 toward which the square pivot 32 moves when the bolt 8 is pushed out of the lock. The tumblers 13 (three on one side of the tang 9 and three on the other side) lie between two plates 35, 36 (see also Figure 8): one plate 35 is adjacent to the bottom 2 of the casing and is termed lower plate, while the other plate 36, being meant to make contact with the cover 6, is termed upper plate. Since the plates 35 and 36 are identical, their details are described hereinafter with reference only to the lower plate 35, which is shown more clearly in Figures 5, 6 and 7 and which, as shown in Figures 1 and 3, substantially duplicates the profile of the tumblers 13. The plates 35, 36 in fact comprise a central portion 37 from which an expansion 38 protrudes upwards. The plates 35, 36 are mutually fixed (at a distance which corresponds to the thickness of the tumblers 13 and of the tang 9) by means of screws which are screwed into spacer bushes 39 and 40 which are driven through the slots 16 and 17 of the strips 14 of the tumblers. The mutual fixing of the plates 35 and 36 also locks, between said plates, a square pivot 41 which is arranged adjacent to the wings 25 of the retainer laminae 15 but above the notch 33, at the same distance as the square pivot 32 from the notch 34. The plates 35 and 36 are preset so that they can perform slight horizontal movements in the direction A while changing the code of the lock. For this purpose, slots 42, 43 are formed in the plates 35, 36 (only the slots related to the plate 35 are visible in the drawing); the slots are elongated in the direction A and are adapted to be engaged respectively by pins 44, 45 which protrude inward from the bottom 2 and by identical pins (not shown in the drawing) which protrude from the cover 6. The pins 44 and 45 are fixed to the bottom 2 and to the cover 6 and their height does not exceed the thickness of the plates 35 and 36, so as to avoid interfering with the strips 14 and the laminae 15 of the tumblers. A bracket 46 is fixed between the expansions 38 in order to provide an abutment for a plurality of springs 47, each of which is superimposed on a respective extension 48 of the strips 14. The springs 47 actuate the tumblers 13 downwards in order to move and keep the square pivot 32 in the position in which it is engaged between the upper teeth 30 of the laminae 15 and thus block the movement of the bolt 8. Respective longitudinal slots 49 are formed in the lower plate 35 and in the upper plate 36 in alignment with the square pivot 32 (see Figures 5 and 6); their dimensions are chosen so as to allow the sliding of the square pivot 32, and their length substantially matches the length of the openings 29 of the tumblers. The slots 49 of the lower plate 35 and of the upper plate 36 also have, at the region for engaging between the teeth 21 and 22, a recess 50 which is shaped so as to form, in each plate 35 and 36, a tooth 51 which lies opposite the notch 34 and is adapted to be engaged by the square pivot 32 when the bolt 8 is fully extracted from the casing of the lock. A lever 52 is accommodated in the recess 50 of the lower plate 35 and is pivoted in a rocker-like fashion on a pivot 53 which is rigidly coupled to the bottom 2. The lever 52 is accordingly co-planar to the plate 35, is no thicker than the plate 35, and is L-shaped, with an arm 54 which extends toward the rear wall 4 and an arm 55 which descends toward the lower wall 5. The vertical arm 55 is shaped, at its end, so as to be in contact with the back of the tooth 51, i.e., on the opposite side with respect to the front side on which the square pivot 32 acts. The arm 54 instead has a pawl 56 which is adapted to cooperate with the square pivot 32, as will become apparent hereinafter. An identical lever 52 is also accommodated in the recess of the upper plate 36, adjacent to the cover 6, and is articulated in the cover 6 and accordingly cooperates with the square pivot 32. The second lever 52, however, is not shown in the drawings. A contoured body 58 is fixed by means of screws 57 to the bottom 2 of the casing and below the tang 9 of the bolt 8 (see Figures 1-4). The body 58 has a central prism-shaped portion 59, in which there is a notch 60 which is open toward the lower wall 5 and the rear wall 4 of the casing. An extension 61 protrudes toward the tang 9 from the central portion 59 and is lateral with respect to the keyhole 20. The portion 59, the extension 61 and the conveniently curved lower edge 62 (Figure 5) of the plates 35 and 36 surround a region which is wide enough to allow the rotation of the key 19 once it has been inserted in the casing through the keyhole 20 and into which the strips 14 protrude with their lower ends 18. The extension 61 engages a recess 63 of the plates 35 and 36 so as to constitute an abutment for the movement of the plates 35 and 36 toward the front wall 1. A lever 65 is articulated in a rocker-like fashion in the recess 60 by means of a pin 64 and comprises a first arm 66, which protrudes toward the rear wall 4, and a second arm 67, which protrudes toward the lower wall 5. A plate 68 is fixed transversely on the arm 66; when the arm 66 performs upward oscillations, the plate 68 abuts against the lower ends of the wings 25, which of course protrude out of the lower edge of the plates 35 and 36. The oscillating strokes of the arm 66 are limited by a threaded bush 69 which is fixed to the bottom 2 and is used not only as a stroke limiter for the end 70 of the arm 66 but also to screw in screws for fixing the cover 6. A spring 71 is interposed between the arm 66 and the base of the extension 61 and acts so as to retain the lever 65 with the arm 67 in abutment against the internal wall of the recess 60 following the provision of a hole 72 formed in the portion 59. The hole 72 is aligned with a sleeve 73 which protrudes from the portion 59 toward the front wall 1 at right angles to said wall. A stem 74 is slidingly guided in the sleeve 73 and in the hole 72 and protrudes with one end from the sleeve 73 to enter a bush 75 which is rotatably interposed between the sleeve 73 and the front wall 1 and is coaxial to the sleeve 73. The bush 75 has a collar 76 which is rotatably inserted in a hole 77 of the front wall 1 and is aligned with the stem 74. Two substantially mutually opposite radial fins 78, 79 (see Figure 2) are rigidly coupled to the bush 75, proximate to the collar 76, and are adapted to alternately abut against an internal protrusion 80 of the front wall 1. A sector 81 is rigidly coupled to the bush 75, at the end that is adjacent to the sleeve 73, and forms an axial pusher cam which has an inclined plane 82 which lies in a helical configuration around the stem 74 and is adapted to interfere with a rib 83 of the tang 9. The cam 81 is capable of assuming two angularly offset positions, which are set by the abutment of the wing 78 or 79 against the protrusion 80. In one of these positions, shown in Figure 2, which constitutes the inactive position, the cam 81 lies outside the sliding plane of the rib 83, so as to allow the bolt 8 to slide freely. When the bolt 8 is in the position for expulsion from the casing and the tumblers 13 have been lifted into the position in which the notch 34 is in front of the square pivot 32, by virtue of the rotation of the bush 75 in the other angular position of the cam 81 the inclined plane 82 acts against the edge of the rib 83, causing a further small movement of the bolt 8 until the tang 9 stops against the front wall 1. In this position of the bush 75 it is possible to change the code in the manner described hereinafter. In the inactive position, the bush 75 is kept in abutment against the protrusion 80 by a pre-loaded spring 84 which is wound around the stem 74 and has an end which acts on the sector 81 and another end which is rigidly coupled to the sleeve 73. An adapted tool 85, for example a so-called hexagonal socket head wrench, is used in order to actuate the rotation of the bush 75 from the inactive position to the position for engaging the rib 83; through a threaded access hole 86, said wrench engages a hexagonal choke 87 of the hole 88 in which the end of the stem 74 engages. Conveniently, the hole 88 can be closed by an Allen screw 89 which can be screwed in by the same tool 85. Tool 85, after passing through the choke 87, can be pushed axially so as to act on the stem 74, so as to actuate the oscillation of the lever 65 until the plate 68 abuts against the wings 25. In order to change the code with the described lock, the user must have not only the new key and the tool 85 to be inserted through the choke 87 but also the old key, since the operations can be performed only when the door is open and when the bolt 8 is fully external to the lock. The code is changed as follows. By operating the lock with the old key, the bolt is moved into the fully extracted position, shown in Figure 1, which is obtained, in the illustrated example, at the end of four turns of the lock. In this position, the opposite ends of the pivot 32 are adjacent to the teeth 59 of the plates 35 and 36 and the pawls 56 of the levers 52 rest on top of said ends. It should be noted that during the sliding of the tang 9 the movement of the plates 35 and 36 is prevented by the abutment of the pin 41 against the wings 25 of the laminae 15. The laminae 15 in fact can move only in the direction B due to the bushes 12 and 28 which are guided in the slots 26 and 27, and the position of the notches 33 with respect to the pivot 41 is such that the engagement of the pin 41 in the notches 33 requires an additional lifting of the laminae which cannot be obtained with the key but can be achieved only by means of the lever 65. By inserting the tool 85 through the choke 86, the stem 74 is in fact moved until it abuts against the arm 67 of the lever 65. Then, by pushing further, the lever 65 is caused to oscillate and, together with the arm 66, lifts the tumblers 13 to the level at which the notches 33 and 34 face the pivots 41 and 32. In particular, the notches 34 are at a level that lies above the teeth 51. At this point, by turning the tool 85 the bush 75 is turned and, due to the action of the cam 81 on the rib 83, there is an additional movement of the bolt 8, since the pivots 41 and 32 can now engage in the notches 33 and 34. In particular, the pivot 32, by entering the notches 34, acts on the teeth 51 of the plates 35 and 36 which are accordingly moved by an extent which corresponds to the depth of the notches 33 and 34, carrying the strips 14 away from the laminae 15, which cannot follow the movement of the plates 35 and 36 because they are prevented from doing so by the bushes 12 and 28. Following the separation of the strips 14 from the laminae 15, the teeth 21 disengage from the teeth 22. At the same time, the teeth 51 of the plates 35 and 36, by acting on the arms 55 of the levers 52, force the levers 52 to oscillate into the position in which the pawls 56 engage the pivot 32. The lock is, at this point, in the configuration of Figures 3 and 6, ready for code changing. At this point the new key is inserted and actuated so as to return the bolt 8 inside the casing. With a first angle of rotation of the new key, the strips 14 are raised according to the new code set by the new key. Once the new position of the strips 14 has been reached, the tool 85 is removed, so as to allow the separation of the lever 65 from the wings 25 and of the cam 81 from the rib 83 and therefore allow the free sliding of the tang 9 and of the bolt 8. The further rotation of the new key causes the movement of the bolt 8 and therefore of the pivot 32 which, by acting on the cams 51, forces the levers 52 to rotate in the direction in which the arms 55 act on the back of the teeth 51 of the plates 35 and 36. In this manner, the entire pack composed of the plates 35 and 36 and of the strips 14 is returned adjacent to the laminae 15, causing the engagement of the teeth 21 between the teeth 22 before the pivots 32 and 41 leave the notches 34 and 33. As soon as the pivots 32 and 41 have left the notches 34 and 33, by removing the new key the pivot 32 engages between the upper teeth 30 by means of the springs 47 which, by actuating the strips 14 downwards, also move down the laminae 15 by virtue of the coupling between the teeth 21 and 22. It is evident that an intervention between the strips 14 and the laminae 15 modifies the tumblers 13 according to a new code which corresponds to the code of the new key. It is particularly important that by acting on the lever 65 it is possible to restore the tumbler reset position if code errors occur due to incorrect operation. The disclosures in Italian Patent Application No. BO98A000132 from which this application claims priority are incorporated herein by reference. Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims: A lock with flat tumblers and changeable code, comprising a box-like body (1-6) which slidingly accommodates a bolt (8) provided with a tang (9) which has teeth (10) for moving the bolt by means of a double-pattern actuation key and with a transverse pivot (32) which engages in openings (29) of the tumblers (13) which lie in the sliding direction (A) of the bolt (8) and have, along their longitudinal edges, mutually opposite teeth (30, 31) which form passages through which said pivot (32) advances by successive turns of the lock, each tumbler (13) being composed of a first part (15), which is provided with said openings (29) and is guided at right angles to said tang (9) between a position for locking said bolt (8), in which said pivot (32) engages between the teeth (30) of said opening (29), and a position for the sliding of the bolt (8), in which said pivot (32) is slideable through said passages, and by a second part (14) which is mounted between two plates (35, 36) which are mutually rigidly coupled and are guided parallel to the sliding direction (A) of said bolt (8), said second parts (14) being guided between said plates (35, 36) at right angles to said tang (9) and parallel to said first parts (15) and being actuatable by means of said double-pattern key, said first and second parts (15, 14) having mutually opposite sets of teeth (21, 22) which are adapted to mutually mesh in order to keep said parts (15, 14) coupled in a direction (B) which is perpendicular to the bolt (8), at least one (35) of said plates (35, 36) being provided with an opening (49) which allows the free sliding of the pivot (32) of the bolt (8) and forms an abutment tooth (51) for said pivot (32) when the bolt (8) is fully extracted from said box-like body (1-6); characterized in that it comprises means (65, 75) for moving the tumblers (13) and the tang (9) which, when said bolt has been actuated into the position for full expulsion from said lock, can be actuated sequentially by means of a tool (85) which is driven through a front hole (77) of the lock, said tool being movable between an active position and a passive position, said tool, in said active position, being adapted to actuate said tumblers (13) into a position in which said pivot (32) is in front of a notch (34) which is located at a level which is different from the level of said passages between the teeth (30, 31) and to actuate said means (75) for moving the tang (9) of the bolt (8) so as to move said pivot (32) so that it acts on said tooth (51) and engages said notch (34) in order to move said plates (35, 36) into a position in which the set of teeth (21, 22) of said first and second parts (15, 14) are mutually disengaged, so as to allow a new key to arrange said second part (14) of the tumblers (13) according to a new code, said tool, in said passive position, being adapted to actuate said movement means into a position for disengagement from said tumblers (13) and from said tang (9) in order to allow the sets of teeth (21, 22) of said first and second parts (15, 14) to mutually engage according to the new code. The lock according to claim 1, characterized in that said movement means for moving the tumblers (13) comprise a lever (65) which is pivoted in a rocker-like manner in contrast with a return spring (71) and has an arm (66) which acts on said first part (15) of the tumblers and a second arm (67) on which said tool acts through a front hole (77) of the lock. The lock according to claim 2, characterized in that said lever (65) is pivoted in a body (59) which is fixed to the inside of the lock and has a sleeve (73) in which a stem (74) is slideable, one end of said stem acting on said second arm (67) of said lever (65) and the opposite end being accessible through said front hole (77) of the lock. The lock according to claim 3, characterized in that said means for moving the bolt (8) comprise a bush (75) which is interposed between said sleeve (73) and the faceplate (1) of said lock and has an axial through hole (88) which is engaged on one side by said stem (74) and is surrounded, on the opposite side, by a collar (76) which is rotatably inserted in the front hole (77) of said faceplate (1), said bush (75) being able to rotate coaxially to said sleeve and being provided with a cam (81) and with two abutments (78, 79) for retaining said bush in two angularly offset positions, allowing the sliding of the tang (9) in one of said positions while in the other position it retains said tang in the position in which said sets of teeth (21, 22) are mutually disengaged. The lock according to claim 4, characterized in that said hole (88) of said bush (75) has a polygonal choke (87) for the side-fit engagement of said tool (85). The lock according to claim 5, characterized in that said sleeve (75) has a threaded access hole (86) in which a closure pivot (89) can be screwed. The lock according to claim 6, characterized in that a preloaded spring (84) is arranged around said stem (74) and is adapted to actuate said bush (75) into said position for the sliding of the tang (9).

Inventors: ERRANI DEO, ERRANI, DEO
Applicants: CISA SPA, CISA S.P.A.
Application year: 1999
Main classification: E05B35
IPC codes: E05B35, E05B15