Patent GB-1225991-A (GB)
IPC: E05B27/08
Filed: 1968-02-28
Abstract: 1,225,991. Locks. B. J. MONAHAN. 28 Feb., 1968 [15 March, 1967], No. 9591/68. Heading E2A.  A lock comprises a first member 15e, 15f and 15g or 111 having a recess 40 or 113 defined by spaced front and rear parallel surfaces, a number of pairs of aligned tumbler receiving slideways 15c, 15d or 121, 125 in said first member on opposite sides of the recess each pair of aligned tumbler receiving slideways extending transversely forwardly and rearwardly from said parallel surfaces, a second member 42 or 118 located between and abutting said parallel surfaces of said first member, one of said members 15e, 15f, 15g or 118 being mounted for movement with respect to the other, the surfaces of both mem-  bers continuing to abut during the relative movement between the members, the interfaces between said relatively movable members establishing spaced front and rear shear interfaces for the lock, said second member 42 or 118 having a locking pin receiving slideways 47 or 127 extending completely therethrough where they confront and are in respective alignment with the tumbler receiving slideways of said first member in a locking position of said movable member a tumbler assembly disposed in each pair of aligned tumbler receiving slideways and the corresponding locking pin receiving slideway, each tumbler assembly comprising a locking pin 45 and spacer members 51, the locking pins 45 being slidably disposed in said respective locking pin receiving slideways of said second member and movable across said shear interfaces so as to extend in locking condition varying distances into said tumbler receiving slideways, each locking pin having a length equal to the length of the associated slideways of the second member, means providing a reference abutment shoulder 48, 115 at the forward end of the lock, spacer members of the tumbler assemblies in said tumbler receiving slideways of said first member which spacer members include a varying number from zero to any closed finite number of wafers of identical thickness in front of the locking pins, resilient means 52 in the rearwardly extending tumbler receiving slideways of said first member for urging the tumbler assemblies of locking pins and spacer members toward said reference abutment shoulder when said movable member is in said locking position, the locking pins then extending across said front shear interface to prevent movement of said movable member, said second member having wafer storage slideways 50 or 130 therein associated with the respective locking pin receiving slideways of said second member, other identical wafers filling each of said wafer storage slideways, said wafer storage slideways being brought into alignment with the respective pairs of tumbler receiving slideways of said first member when the movable member is in a tumbler changing position, said wafers then being transposable between said wafer storage slideways of the second member and the tumbler receiving slideways of the first member each of said locking pins and said locking pin receiving slideways and said wafer storage slideways having a length which is an integral number of wafer thicknesses greater than the overall length of the largest number of wafers which are transposable between any forwardly extending tumbler receiving slideway of the first member and the corresponding wafer storage slideway of the second member and key receiving means 22 or 104 in said abutment shoulder providing means for receiving a key with tumbler engaging shoulders extending beyond said reference abutment shoulder for moving the various tumbler assemblies rearwardly in said slideways against the force of said resilient means. In a first construction (Figs. 4 and 6) the first and second members form a barrel assembly the first member consisting of a cylindrical shaft 15e having an enlarged head 55 providing a shoulder 57, an annular barrel 15f which provides the forwardly extending tumbler receiving slideways 15c and an annular barrel 15g which provides the rearwardly extending tumbler receiving slideways 15d, the two barrels are secured in place by pins 58, 60 and are spaced to provide the recess 40 between them in which the second member 42 is disposed. The member 42 has radial projections 68 which are received in slots 70 in a lock housing 3 to prevent rotation of the member 42 relative to the housing; a circlip 80 prevents axial movement of the barrel assembly 15. The arrangement allows the shaft 15e and the two barrels to rotate as a unit relative to the housing and the member 42, a tongue (not shown) is secured to the barrel which when the housing is secured to a door engages the door frame in the locking position to prevent release of the door. When a correct key is inserted into the lock its tumbler engaging shoulders move the tumbler assemblies so that the locking pins are wholly disposed in the member 42 with their end faces aligned with the shear interfaces and the shaft 15e and the barrels can then be rotated. To change the lock combination a tumbler changing key is inserted into the lock and is used to rotate the shaft 15e and the barrels 15f, 15g counterclockwise to a tumbler changing position; the tumbler changing key used for this purpose is identical with the key which normally operates the lock except that a lug of the normal key which enters a notch 30 (Fig. 6) formed in a flanged head portion 3a of the housing is shorter than the corresponding lug 26' of the tumbler changing key; both keys also have identical inner radially extending lugs adapted to fit within a notch 32 formed in the barrel of assembly 15 and in the tumbler changing position the notch 32 is disposed opposite a notch 35 (not shown) formed in a lip 31 of the head portion 3a of the lock housing which notch 35 has a depth equal to the radial height of the lug 26' of the tumbler changing key but is too shallow to receive the higher lug of the normal key; thus the tumbler changing key can be removed from the lock in the tumbler changing position whereas the normal key cannot; the removal of the first tumbler changing key enables a second tumbler changing key with a different disposition of its shoulders to be inserted into the lock and since in the tumbler changing position the wafer storage slideways in the member 42 are aligned with the tumbler receiving slideways of the first member the insertion of the new tumbler changing key changes the disposition of the wafers in the forwardly and rearwardly extending tumbler receiving slideways so that the combination is changed and when the lock is restored to the locking condition a new key with the revised shoulder disposition but with a normal length lug is required to position the locking pins in the unlocking positions. The wafer storage slideways each accommodate five wafers and the maximum number that can be accommodated in each forwardly extending tumbler receiving slideway is four so that the locking pins can never wholly leave the locking pin receiving slideways in the member 42; the last wafer in each of the rearwardly extending tumbler receiving slideways is provided with a rearwardly extending pin to limit its rearward movement and the combined length of the various tumbler assembly members is such that this wafer can never wholly leave the rearwardly extending slideway. In a second construction (Figs 14 and 15) the member 111 having the recess is a body of the lock and the recess is a rectangular channel cut in the centre portion thereof and extending parallel to a front wall 106 of the lock; the reference abutment shoulder 115 is the rear face of the front wall 106. The second member 118 is a rectangular bolt which slides in the channel 113 and the key after entering the slot 104 in the front wall 106 then enters a rectangular slot 120 in the lock body 111. The slideways 121, 125, 127 are arranged in lines and the wafer storage slideways 113 are disposed beneath the slideways 127; there are however only five wafer storage slideways whereas there are seven of each of the other slideways and with this arrangement the two outside groups of tumbler receiving slideways have no corresponding wafer storage slideways and so they are not provided with wafers but instead with cylindrical spacer members. The insertion of a normal key into the lock energises a solenoid 140 by causing the tumbler assemblies in the two outside slideways to operate the contacts of two series connected switches 160, 160' to closed positions so that the solenoid is connected to a power supply; when the solenoid is energised it pulls an arm 42 attached to the upper end portion of the member 118 upwardly against an abutment shoulder formed by the shank of a screw member 143 so that the member 118 is moved in the channel 113; the member 118 is normally urged downwardly by a spring; movement of the member 118 to the position where it abuts the screw operates a mechanism or moves a bolt to permit a door to be opened. The screw member 143 has a knob 144 accessible from within the door when the lock is in use and which can be turned to withdraw its end portion from within the slide channel 113 to permit the member 118 to be moved further upwardly by the solenoid until the member 118 abuts a shoulder 149; in this position the various wafer storage slideways 138 in the member 118 are aligned with the slideways in the body and inserting a different key into the lock alters the disposition of the wafers in the various slideways so that the lock combination is changed to that of the new key. Normally when the key is withdrawn the contacts of switches 160, 160' are open so that the member 118 drops under the urge of its biassing spring; for tumbler changing it must be held in the raised position and for this purpose a bore 147 is provided in the member 118 into which the screw member 143 can be inserted by turning its head; after the combination ha