Patent GB-1223040-A (GB)
Title: Improvements in magnetic locking devices
Inventor: HEIMANN GEORG
IPC: E05B47/00
Filed: 1968-04-05
Abstract: 1,223,040. Magnetic locks. G. HEIMANN. 5 April, 1968, No. 16616/68. Heading F2A. A magnetic locking device includes two lock parts 112 which can move relative to one another when the device is unlocked; a plurality of recesses 8 located in a first of the lock parts 2; a plurality of permanently magnetized tumblers 3 each located in a respective one of the recesses in the first lock part so that part of the tumbler protrudes from its recess when the device is locked; a plurality of recesses 4 in the second lock part 1 with which the protruding parts of the tumblers can engage to prevent relative movement of the two lock parts; the magnetic polarities and shapes of the tumblers being such that due to the magnetic interaction of the latter, the protruding parts of the tumblers are maintained in engagement with the recesses in the second lock part, application to the device of a key serving to move the plurality of tumblers such that the two lock parts can be moved relative to one another. In one construction Fig. 1 a plurality of tumbler ducts 5 are formed in the second lock part 1, each duct being of annular shape and passing through two of the recesses in the second lock part, the orientation of the tumblers when the locking device is locked is such that the parts of the tumblers which protrude from their recesses; cannot be moved along the tumbler ducts by attempted relative movement of the two lock parts and, when the key is applied to the locking device, it orientates the protruding parts so that the latter can be moved along the tumbler ducts by relative movement of the two lock parts. The part 1 is a housing and the part 2 is a cylinder core received in the housing and provided with a key slot which extends through it. The protruding parts of the tumblers form heads with inclined sides and the ducts 5 which similarly have inclined sides. Each tumbler either includes a magnet plate secured to the rest of the tumbler by a pin integral with the rest of the tumbler or they are made of material which can be magnetized. The key has disc magnets disposed along its shank which interact with the tumblers to rotate them. When the key is withdrawn the tumblers interact with each other so that they are rotated to the locking positions. The heads can have their sides either symmetrically or asymmetrically arranged, the ducts being correspondingly shaped. In a modification the tumbler heads are enlarged and formed with a groove and the duct has a tongue which is engageable with the groove. The tumblers shown each have a cylindrical portion in the recess 8 but in a modification each tumbler has a frustoconical portion and the corresponding recess 8 is also frusto conically shaped, this prevents the tumblers falling into the keyway if a file is used in an effort to pick the lock. In a further modification each recess 8 is provided with a rib Fig. 5 and the tumblers each have a groove which is engageable with the rib, the ribs and grooves align the tumblers so that their heads complement the ducts and aid the rotation of the tumblers by the key. Each rib and groove can be triangular as shown or can be curved; each groove can be of the same width throughout its length or can diverge towards each end. As shown there are two rows of tumblers, with the tumblers in each row arranged axially but in a modification the tumblers can be arranged radially so that there are three or four tumblers disposed around the key in which case the key is either square or substantially triangular in shape, in a modification of this construction there can be three or four rows of tumblers arranged round the key. An alternative construction Fig. 15a has the recesses 4 in a sleeve instead of in the housing the sleeve being contained in the housing so that it is freely rotatable. The cylinder core has a flange provided with teeth which in the locking condition of the lock engaged corresponding recesses in the housing; the ducts are in the sleeve and are parallel to the axis of the cylinder core; when the correct key is inserted into the cylinder core the tumblers are rotated so that they can move along the ducts and allow the cylinder core to be moved axially against the bias of a spring 24 to free the teeth of the cylinder core from the recesses in the housing; when this has been done the cylinder core and the sleeve can be rotated in the housing. The sleeve is prevented from axial movement in the housing by a ring 27 which if sufficient pressure is exerted on the cylinder core in the locked condition will shear and it is stated that the end portion of the sleeve which is frusto conically shaped will then engage with an internal frusto-conical surface of the housing and prevent relative rotation of the sleeve and the housing. A construction is also described Fig. 19a in which the two lock parts are discs the ducts being arcuate and in the uppermost disc, the uppermost disc being rotatable on the lowermost disc when the tumblers are rotated by the key which is engageable with the surface of the uppermost disc and located by pegs engaging recesses in the disc. A further construction is described Fig. 20 in which the two lock parts are in the form of upper and lower plates, the upper plate being slidable on the lower plate in the unlocking condition, there being three tumblers and the ducts being parallel with the direction of sliding of the upper plate. The upper plate has a rim, surrounding it and forming a recess in which the key is placed for rotating the tumblers so that their heads complement the profile of the ducts to allow the movement of the two plates. In a still further construction Fig. 16a the ducts are omitted; the two lock parts consist of a housing 1 and a cylinder core 2, the recesses 4 being in the housing and the recesses 8 in the cylinder core and the tumblers are disposed so that their axes of rotation are parallel with the axis of rotation of the cylinder core; the shape of the tumblers is such that when the key is in the key slot in the cylinder core the tumblers are rotated so that one surface of each substantially completes the periphery of the cylinder core so that the cylinder core with the tumblers can be rotated in the housing; when the key is withdrawn the mutual attraction of the tumblers rotates them so that they project into the recesses 4 in the housing and prevent the rotation of the cylinder core.