LOCK WITH KEY ISOLATION USING TRANSFER TUMBLERS

Abstract: This specification describes a lock where a key (10) is inserted into a key cylinder (B) and where the key sets a series of transfer tumblers (12). The tumblers project from the key cylinder (8), and the tumblers, in turn, set a series of lock opening elements into their prescribed positions. As the key-cylinder is rotated the transfer tumblers (12) are moved out of contact with the elements. Only at this time can the lock be opened, provided that the elements had been correctly set.

Description: This invention relates to pick-resistant key operated locks. The general philosophy of this lock follows the basic concepts embodied in the Patent US-A-4,599,877 issued to me on July 15, 1986. In that patent it was the key itself that set the lock opening elements into their prescribed positions. The key and the key passage were then isolated from the elements before the lock could be opened. The resulting designs were rather complicated and there was the additional difficulty that the key cylinder had to be rather thin so that a good part of the key had to be exposed to be able to set the elements. The locks described in that patent required a separate mechanism to accomplish the key isolation. In most cases this required a separate cylinder or gate, geared to the key cylinder. In the present invention, the key isolation is accomplished in a far simpler manner. In many conventional locks, a key is inserted into a cylinder. A set of tumblers is moved by the key into the desired positions so that the ends of the tumblers line up with the surface of the cylinder, thus permitting it to turn. It is important to note that in nearly all such locks each tumbler has to be matched to a particular cut in the key. In the usual case, a deep cut requires a long tumbler (or an appropriate section of the tumbler) while a shallow cut requires a short tumbler. Such locks, in general, are easy to pick because the tumblers are accessible to a pick or other tool inserted into the key slot. According to the present invention, there is provided a key-operated lock comprising an outer case, a key receptor body, such as in the form of a cylinder, extending axially within the outer case and rotatable relatively thereto, and one or more tumblers carried by the key receptor body to shift laterally relatively thereto and thereby perform the locking and unlocking function, the receptor body having an axially-extending key-receptor slot into which the lock-operating portion of a key is inserted thereby to engage the tumblers and shift them laterally, characterised in that within the outer case and surrounding the key-receptor body there is a main barrel which is rotatable relatively to the case in the unlocked condition but constrained against rotation beyond a limited angular extent in the locked condition, and one or more locking elements are carried by the main barrel and are movable relatively thereto to lock and unlock the main barrel, each locking element being wholly outside the key-receptor body and being operated by a portion or portions of a respective tumbler projecting outside the key-receptor body, whereby the locking elements cannot be reached by a pick or the like inserted into the key-receptor slot. Preferably the receptor body is a key cylinder with a plurality of parallel transverse through-slots at different axial positions along the receptor body, a plurality of tumblers are slidable endwise each in a respective one of the lateral slots with their ends projecting out beyond the outer periphery of the key cylinder into engagement with respective locking elements in the main barrel, the portions of the tumblers lying within the key cylinder being configured to co-act with the key when it is inserted into or withdrawn from the key-receptor slot whereby the tumblers are shifted endwise by profiling on one or both edges of the key, and the key cylinder with the tumblers is rotatable relatively to the main barrel from an active into an inactive angular position in which the tumblers can no longer engage and operate the locking elements. Preferably also, the lock further comprises an interlock which locks the main barrel in one angular position relatively to the outer case, and regardless of the setting of the locking element or elements, until the key receptor body is turned relatively to the barrel, e.g. through 90°, into an angular position in which interlock release can occur; and in the position of interlock release the angular disposition of the tumbler or tumblers carried by the key receptor body is such that they cannot operatively engage the locking element or elements. In the preferred embodiment, the key enters a more-or-less conventional key cylinder. It positions a series of tumblers (preferably of the flat type) in the manner previously described, except that when set by the key the tumblers do not line up with the peripheral surface of the key-cylinder, but project from it. As the key is inserted, it is the tumblers that in turn set a series of locking elements in the main barrel to permit the lock to open. But before this last action can occur, the key-cylinder and its tumblers must be turned to a position of interlock release in which the tumblers can no longer operatively engage the locking elements. Because the tumblers act only as intermediate members between the key and the lock opening (or lock locking) elements, I call these tumblers "transfer tumblers". The following is a detailed description of a number of embodiments of the invention, given by way of example and with reference to the accompanying diagrammatic drawings, in which: Figure 1 shows the vertical section of one embodiment of my lock. Figure 2 shows a section of Figure 1 taken approximately along line 2-2. Figure 3 shows a section of Figure 1 taken approximately along line 3-3. Figure 4 shows a section of Figure 1 taken approximately along line 4-4. Figure 5 shows a partial section of Figure 1 taken along line 5-5. This section shows the details of an interlock that permits the inner main cylinder to revolve at the appropriate time. Figure 6 shows a lock-opening element used in Figure 2. Figure 7 shows a lock-opening element used in Figure 3. Figure 8 shows a lock-opening element used in Figure 4. Figure 9 shows a section of Figure 1 taken along line 4-4 after the key has turned 90° from the position shown in Figure 4. Figure 10 shows the section of Figure 4 except that an incorrect key has been inserted into the key cylinder. Figure 11 shows a transfer tumbler. Figure 12 shows a slightly different design of the lock-controlling element as would be used in the section of Figure 2. Figure 13 is a side view of the different design of the lock-controlling element shown in Figure 12. Figure 14 shows a cross section taken of a different lock, where the tumblers are designed to be used with a key having bitting on one edge only. Each tumbler is kept in the position shown by a spring until moved by the key. Figure 15 shows the general design of a key to be used with the lock of Figure 14. Figure 16 shows the lock of Figure 14 after a key has been inserted into its key-cylinder. Figure 17 shows a section of a third embodiment of my invention. Here the transfer tumblers set by the key are not identical. Their central slot is located in different positions. Figure 18 shows three different tumblers for this third embodiment. Figure 1 shows a schematic diagram of the principal parts of one embodiment of my invention. The lock consists of an outside case 2 which may be a cylinder. The case 2 is provided in its inner wall with at least two diametrically opposed axially extending notches 4 and 4 that can also be seen in the sections shown in Figures 2, 3 and others. The outside case 2 contains a main cylinder 6 arranged to rotate within it for the lock to open or be closed. The main cylinder 6 further contains an inner or key cylinder 8 that can rotate in the main cylinder 6. A key profiled along both edges, for the reason explained below, is shown at 10 in Figure 1. It fits into a full length slot 9 in the key-cylinder 8 as shown in Figure 1, and as shown in dotted lines in Figure 2. The key-cylinder 8 is provided with a series (three in Figure 1) of cross slots just large enough to permit transfer tumblers 12 to slide freely through them. Figure 11 shows one of these tumblers 12, each tumbler having a slot through which the key passes. In this embodiment the tumblers 12 are all identical. The reason for the key 10 being profiled along both its edges is that it should be able to position the tumblers 12 as it is inserted, without the use of springs. It should be understood that the tumblers 12 are usually made of thin metal as compared to the width of the key 10. In the plane of each tumbler there is located a laterally sliding locking element 14a, 14b or 14c. These locking elements are disposed in a slideway in the main cylinder 6, to slide in the same directions as the transfer tumblers 12, and they are separated from one another by spacers 16. As shown in Figures 6 to 8, each locking element has a cut-out through which the key-cylinder 8 passes and within which the respective transfer tumbler 12 lies. Each locking element also has at one or both of its ends a projecting nib or nibs to engage in one or other of the notches 4 in the outside case 2 to prevent the main cylinder 6 turning. It will now be seen that as the key 10 is inserted into the key-cylinder 8, the tumblers 12 will be shifted laterally in their slots in the key cylinder 8. This in turn shifts the locking elements 14a, 14b, 14c, by contact of the ends of the tumblers with the edges of the cut-outs in those elements, so that the nibs of the locking elements are withdrawn from the notches 4. This motion will result in the positions shown in Figures 2, 3 and 4. This would permit the cylinder 6 to turn in the case 2 except for one more provision. At the bottom of the cylinder 6 there is a cam operated interlock generally indicated at 18 (Figure 1). Its operation was described in my US-A-4,599,877 and a brief description will be repeated here. The cylinder 6 has a radial passage hole 20, shown in Figures 1 and 5, for a pin 22 of the interlocking device 18. This pin 22 can enter a hole 24 in key-cylinder 8 after the key-cylinder has been turned, relatively to the main cylinder 6, into an angular position in which the transfer tumblers 12 are unable to shift the locking elements 14 (into the position shown in Figure 9). When the lock is engaged a tapered outer end 26 of the pin 22, which is spring-urged outwardly, is located in a notch 28 in the outer case 2 as shown in Figures 1 and 5. With the key-cylinder in the angular position in which the tumblers 12 operate the locking elements 14 the outer end of the pin 22 cannot be disengaged from the case 2 but when the key-cylinder 8 is turned 90 degrees counter clockwise (in Figure 5), the hole 24 comes opposite the pin 22 and the tapered end 26 of the pin can be cammed out of the notch 28 against the force of the spring 30. This permits the main cylinder 6 to turn and open the lock, provided the sliding locking elements 14a, 14b and 14c have previously been correctly set. If one or more of these elements have not been set correctly, for instance the element 14c as shown in Figure 10, the cylinder 6 will only turn through a small angle until the nib 32 of the element 14c abuts one or the other end wall 34 of the notch 4 in the outside case 2. It will now be seen that in the final position of the key-cylinder 8, as shown in Figure 9, there is no operative relationship between the key slot 9 and the locking elements 14. To engage the lock, the main cylinder 6 is rotated back to its start position as shown in Figures 2, 3 and 4, and the pin 22 snaps into the notch 28 (Figure 5). This permits the key-cylinder 8 to be rotated clockwise from the position shown in Figure 9 to its starting position as seen in Figures 1 and 5. Now withdrawing the key 10 will move the transfer tumblers 12 into indefinite positions, depending on the shape of the key 10. This, in turn, will shift the elements 14 from their lock release positions and engage the lock. It may have been noted in Figures 6, 7 and 8 that the elements 14a, 14b and 14c have rather narrow side strips 36. In order to make these elements more rugged, I show a modification in Figures 12 and 13. Here the element 38 is made deeper and the end sections 40a and 40b are the full thickness while the side connecting sections 42 are thinner and lie out of the plane of the tumbler 12. The side sections 42 can therefore be made wider, as in Figure 12, without contacting the tumbler 12 when the key-cylinder 8 has been turned into the position shown in Figure 9. In Figures 14 and 16 I show a different embodiment of my invention. The operation of the lock of Figure 14 is similar to that of the previously described embodiment except for the design of the key (Figure 15), the transfer tumblers 43, and the key cylinder 45. Instead of the double ended tumblers shown in Figure 11, I now use a spring-loaded tumbler 43 shown in Figures 14 and 16. The tumbler 43 is located in a transverse slot in the key cylinder 45, as before. While I show only one cross-section of the lock in Figure 14, it should be understood that, as in the previous embodiment, there are several such tumblers at different axial positions. All of the tumblers 43 in the several positions may be alike, as formerly. The key 46 (shown in Figure 15) is different in that it is profiled only along one edge. The key 46 is of a type used today in a great many locks. Because the single bitted key 46 can only shift the tumblers one way, the tumblers 43 have to be pressed against the key by springs. One such spring 48 is shown in Figures 14 and 16, acting between a side lug on the tumbler and an internal shoulder of the key cylinder. The slot 50 in the tumbler 43 is shown in Figures 14 and 16 and is located centrally in the tumbler. The key slot 44 in the cylinder 45 is wider, as indicated by the dotted lines, and extends throughout the length of the key-cylinder 45. As the key 46 is inserted into the key-cylinder 45, the various tumblers are pushed laterally against the forces of their springs, like that shown for the one tumbler 43. Located co-planar with the transfer tumblers 43 are a series of locking elements 51. Their function is exactly the same as the function of the lock elements 14 of Figure 1. When the locking element 51 is in the position shown in Figure 14, the device is locked because the nib 52 of the element 51 is in the notch 54 in the outer casing 56. Assume now that a key, like the key in Figure 15, is inserted into the key cylinder 45. As shown in Figure 16, this will push the tumbler 43 laterally some required distance. This will make one end 58 of the tumbler 43 (Figure 14) act against the inner edge surface 60 of the element 51 and push it into the position shown in Figure 16. In this position, the nib 52 is withdrawn from the notch 54 in the outer casing 56, and the element 51 will permit the cylinder 62 to turn. If the key cylinder 45 is turned 90° counter clockwise, the key cylinder 45, the key 46, the key slot 44 and the tumbler 43 are operationally isolated from the locking element 51. This lock is also provided with a pin interlock exactly such as shown in Figure 5. This pin interlock locks the main cylinder 62 to the outer case 56 of the lock exactly as it did in Figure 1. But when the key-cylinder 45 has turned through 90° the cylinder 62 is released to rotate and open the lock, provided that the elements 51 have previously been correctly set. When it is desired to lock the mechanism, the main cylinder 62 is rotated clockwise. When the cylinder 62 reaches the position shown in Figure 14, the interlocking pin 22 (Figure 5) snaps back so that its end 26 is again in the notch 28 in the outside case. This releases the interlock between the main cylinder 62 and the key-cylinder 45. The key-cylinder 45 can continue to rotate clockwise to a position like that shown in Figure 5. The lock is now closed. The key 46 can be withdrawn from the key cylinder 45 and the components will be as shown in Figure 14. I have stated that the transfer tumblers in the two embodiments so far described can be all alike. If the tumblers of a lock are all alike they, of course, carry no information and the information carried by the bitting of the key has to be matched to the information contained in the shape of the locking elements such as 14 in Figure 1, or 51 in Figure 14. It is entirely possible, however, to use transfer tumblers that differ from each other and make the locking elements all alike such as I show in Figures 17 and 18. Here the transfer tumblers 70 are made to correspond to the bitting of the key 10 in Figure 1. The slot openings 66 in the tumblers must fit the key, but are located at different positions along the tumblers (Figure 18). As the key is inserted into a lock with such tumblers (as in Figure 17) the tumbler ends 68 all align in two straight lines due to the matching of the profiling of the key edges with the positioning of the slots in the tumblers. The locking elements 72 being all alike (like that in Figure 17) now will be forced also to align themselves and the main cylinder will be free to turn. the position of all the lock elements of the lock will be like the element 72 of Figure 17. Note that the alignment of the transfer tumblers 70 in this embodiment is similar to the alignment of tumblers in millions of locks used today, except that in the usual locks the ends of the tumblers themselves permit the locks to open while in my lock the tumblers 70 transfer their positions to another set of lock elements 72 that effect the locking and release of the lock. Because the tumbler 70 (in Figures 17 and 18) provides, by reason of the position of its slot, information as to the bitting of the key, I provide a motion-limiting pin 64 on the key-cylinder that co-acts with an elongated notch 74 (in Figure 18) in the side of the tumbler 70. This permits the tumbler 70 to move under the action of the key, but prevents a lock picker from "feeling" the relationship of the slot 66 to the ends 68 of each tumbler 70. The single bitted key of Figure 15 can also be used with tumblers having slots in different positions and lock elements 51 of identical shape (Figure 14). It should also now be clear that a lock can have only some of its tumblers of one fixed design and the corresponding locking elements of different shapes. The rest of the tumblers can be of different designs and the locking elements co-operating with them of one design. It is even possible to design such a lock with transfer tumblers of random designs, as compared to the bitting of the key, so long as the locking elements are of correct corresponding shapes. Thus the combination of each tumbler and its locking element, together, will match the information provided by a respective bit of the key. While I show three different embodiments of my invention that use sliding locking elements, there are other possibilities. For example, the sliding elements, such as 14a in Figure 2, and 51 in Figure 14, can be replaced by rocking elements, and the key cylinder with its projecting transfer tumblers can operate against the surfaces of these rocking locking elements, such as the elements 4 in Figure 8 of US-A-4,599,877. In Figure 1 I show a spring 80 that presses all the elements 14, with their spacers 16, together axially and against the base 82 of the main cylinder 6 so that gravity and vibration effects will not move the elements 14 after they have been set correctly by the key 10, and after the key 10 and tumblers 12 have been isolated from them. The spring 80 presses against the element 14a and this pressure is transmitted through all the elements 14 and the spacers 16 to accomplish the desired result. For the sake of clarity, I do not show many usual mechanical components in my drawings. I do not show support components, fasteners, rotation stops and other such parts. Such mechanical features are old in the art and need not be illustrated here. The invention may be used for locks for such things as doors, file cabinets, safes and other devices where two mechanical parts are held in a predetermined relative position when the lock is locked, but may also be used for any other application where a key, if a correct one, operates a device. For example, it is very common to use a lock to close or open an electrical circuit when the correct key operates the lock.

Claims: 1. A key-operated lock comprising an outer case (2, 56), a key receptor body (8, 45), such as in the form of a cylinder, extending axially within the outer case and rotatable relatively thereto, and one or more tumblers (12, 43, 70) carried by the key receptor body to shift laterally relatively thereto and thereby perform the locking and unlocking function, the receptor body having an axially-extending key-receptor slot (9, 44) into which the lock-operating portion of a key (10, 46) is inserted thereby to engage the tumblers and shift them laterally, characterised in that within the outer case and surrounding the key-receptor body there is a main barrel (6, 62) which is rotatable relatively to the case in the unlocked condition but constrained against rotation beyond a limited angular extent in the locked condition, and one or more locking elements (14a-c, 51, 72) are carried by the main barrel and are movable relatively thereto to lock and unlock the main barrel, each locking element being wholly outside the key-receptor body and being operated by a portion or portions (58, 68) of a respective tumbler projecting outside the key-receptor body, whereby the locking elements cannot be reached by a pick or the like inserted into the key-receptor slot. 2. A lock according to Claim 1, wherein the key-receptor body is a key cylinder with a plurality of parallel transverse through-slots at different axial positions along the receptor body, a plurality of tumblers are slidable endwise each in a respective one of the lateral slots with their ends projecting out beyond the outer periphery of the key cylinder into engagement with respective locking elements in the main barrel, the portions of the tumblers lying within the key cylinder being configured to co-act with the key when it is inserted into or withdrawn from the key-receptor slot whereby the tumblers are shifted endwise by profiling on one or both edges of the key, and the key cylinder with the tumblers is rotatable relatively to the main barrel from an active into an inactive angular position in which the tumblers can no longer engage and operate the locking elements. 3. A lock according to Claim 2, wherein the locking elements are arranged to slide parallel to the direction of sliding of the tumblers (in the active position) each locking element having end portions lying at diametrically opposite sides of the key cylinder at least one of which end portions has a projecting locking nib (32, 52) to be engaged in and disengaged from a notch or recess (4, 54) in the outer case as the locking element is slid to and fro, and each locking element has between its end portions a centre cut-out through which the key cylinder passes, the locking elements being operated by engagement of the ends of the tumblers with edge surfaces (60) of these centre cut-outs. 4. A lock according to Claim 2 or Claim 3, wherein the tumblers are all alike and the locking elements are different to match the bitting or profiling of the key. 5. A lock according to Claim 2 or Claim 3, wherein the locking elements are all alike and the tumblers are different to match the bitting or profiling of the key. 6. A lock according to Claim 2 or Claim 3, wherein the tumblers are different from one another, the locking elements are different from one another and each tumbler/locking element combination is selected to match the bitting or profiling of the key. 7. A lock according to any of Claims 2 to 4, wherein each tumbler has a slot (50) centrally disposed between its ends through which the key passes. 8. A lock according to any of Claims 2, 3, 5 and 6, wherein the portions of the tumblers lying within the key cylinder have slots (66) through which the key passes, the slots in different tumblers being at different positions along the tumbler. 9. A lock according to Claim 8, wherein limit stops (64, 74) are provided to limit the endwise movement of each tumbler relatively to the key cylinder. 10. A lock according to any of Claims 2 to 9, wherein the tumblers are spring-loaded in one direction and the key has one edge only bitted or profiled. 11. A lock according to any of Claims 2 to 10, wherein the locking elements are all in an axial stack which is spring-pressed axially, whereby the locking elements are held by friction in the positions to which they are set by the tumblers. 12. A lock according to any preceding claim, further comprising an interlock (18) which locks the main barrel in one angular position relatively to the outer case, and regardless of the setting of the locking element or elements, until the key receptor body is turned relatively to the barrel, e.g. through 90°, into an angular position in which interlock release can occur. 13. A lock according to Claim 12, wherein in the position of interlock release the angular disposition of the tumbler or tumblers carried by the key receptor body is such that they cannot operatively engage the locking element or elements. 14. A lock according to Claim 12 or Claim 13, wherein the interlock comprises a spring-urged pin or plunger (22) disposed radially in the main barrel and engaging in a notch or recess (28) in the outer case, and the presence of the key receptor body within the main barrel prevents the interlock pin or plunger from withdrawing from said notch or recess except when the receptor body is in the interlock release position. 15. A lock according to Claim 14, wherein the key receptor body has a radial hole (24) which becomes aligned with the interlock pin in the interlock release position, thereby enabling the interlock pin to retract from the outer case, and free the main barrel for rotation, by partially entering said hole while at the same time locking the main barrel and the key receptor body against relative rotation. 16. A lock according to Claim 14 or Claim 15, wherein the interlock pin has a shaped end portion 26 engaging in the notch or recess in the outer case, this pin end portion and the notch or recess being so co-operatingly configured that relative rotation of the main barrel and the outer case will cam the pin out of engagement in the notch or recess providing the key receptor body is maintained in the interlock release position relatively to the main barrel.

Inventors: RABINOW, JACOB
Applicants: RABINOW, JACOB
Application year: 1988
Main classification: E05B21
IPC codes: E05B29, E05B21