Patent Publication Number: US-3878700-A

Title: Lock for operation by an axially bitted key

Description:
United States Patent [1 1 Lopez [451 Apr. 22, 1975 LOCK FOR&#39;OPERATION BY AN AXIALLY BITTED KEY [76] Inventor: Pedro Lopez, 2295 de Londres St..  
 St. Laurent, Quebec, Canada [22] Filed: June 18, 1974 21 Appl. No.: 480,589  
 [52] US. Cl. 70/363: 70/419: 70/DlG. 49 [51] Int. Cl E05b 27/08 [58] Field of Search 70/363, 362, 419. DlG. 49.  
 [56] References Cited UNITED STATES PATENTS 3.163.034 l2/l964 George 70/419 3.422.646 l/l969 Monahan 70/363 3.524.335 8/1970 George i. 70/363 354L819 ll/l970 Kerr 70/363 Primary E.\&#39;aminerRobert L. Wolfe [57] ABSTRACT A lock adapted to be operated by an axially bitted key and comprising tumblers and a rotation locking plate arranged to be each axially displaced upon actuation by the appropriate key having the right axial bit for the tumblers and also the right axial bit for the locking plate to displace these to predetermined unlocking axial position thereof.  
 8 Claims, 7 Drawing Figures LOCK FOR OPERATION BY AN AXIALLY BITTED KEY This invention relates to a key lock and. more partic ularly. to a lock of the type adapted to be operated by an axially bitted key.  
  For a lock of the above type. the unlocking is obtained merely by predetermined axial displacement of the appropriate key into the cylinder of the lock to produce the required axial displacement of the tumblers into a core inside the lock. The picking of such lock having essentially a single locking feature is still relatively easy.  
  It is a general object of the invention to provide a lock of the above type with dual locking features to make the picking thereof still more difficult than up to now with such lock having only a single locking feature.  
  It is a more specific object of the invention to provide a key lock of the above type which includes tumblers as well as a second locking feature which must all be properly positioned to achieve unlocking.  
  The above and other objects and advantages of the invention will become more readily understandable in the light of the following detailed description of a preferred embodiment thereof. which is illustrated. by way of example. in the accompanying drawings wherein:  
  FIG. 1 is a front or end view of a lock according to a preferred embodiment of the invention:  
  FIG. 2 is a longitudinal cross-sectional view as seen along line 2-2 in FIG. 1:  
  FIG. 3 is a partial view of FIG. 2 illustrating the locking elements in unlocked position:  
  FIG. 4 is a transverse cross-sectional view as seen along line 4-4 in FIG. 2:  
  FIG. 5 is a perspective view of the operative end of a key according to the invention.  
  FIG. 6 is a partial development view as seen along line 66 in FIG. 4; and  
  FIG. 7 is a partial development view as&#39;in FIG. 6 showing the locking elements in unlocked position. together with an associated alarm circuit.  
  The illustrated lock includes a cylindrical casing 1 having external threads 2 for screwing into an appropriate hole in a door or the like closing member. The casing 1 forms a cylindrical aperture 3 defining an inner surface 4. The key receiving end of the casing 1 has a reduced diameter portion forming an internal shoulder 5.  
  A core 6 is rigidly held into the cylindrical aperture 3 by a setscrew 7 through the casing I. An axial bore 8 extends through the core 6 and a stem 9 is rotatably mounted into this bore for rotation therein. One end of the stem 9 projects outwardly from one face of the core 6 and terminates with the corresponding end of the cylindrical casing l. A longitudinal slot or keyway 10 is provided into this end of the stem 9. The other opposite end of the stem 9 is formed in any suitable manner. not shown. for engagement with the bolt of a lock to actuate the same.  
  A series of. in this case. seven&#39;tumbler cavities 11 extend through the core 6 parallel to the stem 9 and an annular shoulder portion 12 is formed at the end of each cavity 11 adjacent the other end face of the core A plug 13, of generally annular form. is positioned into the aperture 3 of the casing 1 adjacent the one face of the core 6. The plug 13 is formed with a radially inward lug l4 engaging into the longitudinal groove or keyway 10 of the stem 9 to rotate the same. while being axially displaceable relative thereto. A series of tumbler passages 15 extend through the plug I3 parallel to the stem 9 and are arranged for registry with the tumbler cavities 11 into the core 6.  
  An auxiliary locking member. or ring 16. is mounted into the cylindrical aperture 3 by engagement around the stem 9 between the plug 13 and the annular shoulder 5 of the cylindrical casing l. The locking ring 16 has a radially inward lug I7 engaging into the longitudinal groove. or keyway 10, of the stem for non-rotatable lengthwise displacement relative to the latter. Tumbler passages 18 also extend through the locking ring 16 parallel to the stem 9 and are arranged for registry with the tumbler passages 15 ofthe plug 13 and the tumbler cavities ll of the core 6. Three compression springs I9 engage at their opposite ends into mutually facing recesses 20 and 21 of the plug 13 and the locking ring I6 respectively. to thereby urge or bias these away from each other.  
  A radially outward lug or projection 22 is formed on the periphery of the locking ring vl6 to non-rotatably lock the latter and the stem 9 relative to the cylindrical casing I. A circumferential groove 23 is formed into the cylindrical surface 4 of the casing l and forms a cir cumferential pathway for circumferential displacement of the radially outward lug 22 therein. as shown in FIG. 3. As will be better appreciated later. the circumferential groove or pathway 23 is arranged at a predetermined longitudinal spacing from the end 24 of the stem 9. A longitudinal groove. or keyway 25, is formed into the cylindrical surface 4 and forms abutment faces 26 along the opposite sides thereof. The opposite sides of the longitudinal groove or key 25 form arc-shaped or curved surfaces 27 curving towards the bottom of the groove 25 and arranged for rotational wedging of the radial projection or lug 22 against the same.  
  As may be seen. the longitudinal groove or keyway 25 intersects the circumferential groove or pathway 23, whereby the lug 22 and the locking ring 16 are nonrotatably restrained at all possible axial positions thereof by the side faces 26 and 27, except fot the above-mentioned predetermined axial position where the lug 22 engages into the circumferential groove 23 for circumferential displacement therein. Furthermore. in order to further confuse unauthorized picking. the curved surfaces 27 allows some rotation of the locking ring 16 and wedging of the lug 22 against the same surfaces to produce catching of the ring in such partly rotated position.  
  A tumbler is mounted into each set of longitudinally registering tumbler cavity 11 and tumbler passages 15 and 18. Each tumbler includes a first pin 28 and a second pin 29 held in end-to-end abutment by a compression spring 30. In order to effect the unlocking. the abutting ends of the pins 28 and 29 must lay intermediate or at the interface between the core 6 and the plug 13, as shown in FIG. 7, besides the aforementioned longitudinal positioning of the locking ring 16.  
  The tumbler pin 28 has a reduced diameter portion 31 projecting axially therefrom at the other end thereof relative to the abutting end and extending outwardly of the core 6. An electrical contact ring 32 is secured onto the stem 9 through an insulating ring 33, of rubber or the like.  
  An electromagnet coil 34 is connected at one end by a lead 35 to the annular contact 32 and at the other by a lead 36 to the secondary of a transformer 37 of a l 10- volt A.C. supply. A manual switch 38 is interposed into the lead 36. The opposite end of the secondary of the transformer 37 is connected by a lead 39 to the casing l to form contacts with the pin portions 31 and to the movable contact 40 of the electromagnetic coil 34. A spring 41 urges the movable contact 40 away from the armature of the coil 34. An electrical sound alarm or bell 42 is connected by a lead 43 to the fixed contact 44 and by a lead 45 to the secondary of the transformer 37.  
  A key 46 according to the present invention is particularly adapted to form an operative lock assembly with the afore-described lock. The key 46 includes a tubular end portion 47 forming an axial cavity 48 projecting at a predetermined depth therein from the free end thereof. A radially inward lug 49 and a radially outward lug 50 project from the opposite cylindrical faces respectively of the tubular end portion 47. The lugs 49 and 50 are respectively arranged to longitudinally engage into the longitudinal groove 10 of the stem 9 and into an appropriate notch 51 into the end of the casing l. The key 46 is axially bitted by a series of axial projections 52 projecting at predetermined distances from an axial reference defined by the surface 53 and registering with the tumbler pins. Obviously. the length of each projection 52 must be complementary of the length of the corresponding tumbler pin 29 and the depth of the axial cavity 48 must be equal to the afore-mentioned preselected distance of the circumferential groove 23.  
  Consequently, when the proper key 46 is correctly engaged around the end of the stem 9. the locking ring 16 slides axially to the afore-mentioned predetermined position and the tumbler pins are retracted to the unlocking position of HO. 7. Then, the locking ring 16 is turned with the stem 9 and the plug 13 to release the bolt of the lock, not shown, by rotation of the key 46.  
 Unless the concurrent correct axial displacement of all the tumbler pins and the locking ring is done. the stem 9 may not be rotated to actuate the bolt of the lock. For instance, if anyone set of tumbler pins is displaced too far, the corresponding pin portion 31 makes contact with the ring 32, thereby causing the coil 34 to close the contact 40 and sound the alarm 42. The latter may be manually de-activated by an authorized person by opening the manual switch 38.  
  If any unauthorized person tries to rotate the locking ring 16, the latter may either refuse to rotate if aligned with any of the surfaces 26 or may partially rotate and get stuck if then aligned with any of the wedging surfaces 27.  
 I claim:  
  I. A lock for operation by an axially bitted key and comprising a casing having an aperture therein, a core fixedly secured to said casing into said aperture, a bolt actuating stem rotatably extending through said core and projecting outwardly therefrom into said aperture, a plug engaged around said bolt actuating stem and secured thereto for rotation therewith into said aperture adjacent one face of said core, an axially displaceable rotation locking body surrounding said stem on the opposite side of said plug relative to said core, and secured to said stem for rotation therewith into said aperture, said core having tumbler cavities extending therein from said one face thereof and lengthwise of said stem. said plug and said rotation locking body having tumbler passages extending therethrough lengthwise of said stem and arranged for endwise registration &#39;with said tumbler cavities. tumblers extending into said cavities respectively and arranged for endwise displacement into the latter and the corresponding tumbler passages, first biasing means urging said rotation locking body away from said opposite face of said plug. second biasing means urging said tumblers for engagement into said tumbler passages, and abutment means provided into said aperture and constructed and arranged to prevent rotation of said body in all axial positions other than a predetermined axial position relative to said stem.  
  2. A lock as defined in claim 1, wherein said casing has an internal surface defining said aperture and cooperatively forming with said abutment means a circumferential pathway for the rotation of said body therein at said predetermined axial position along said stem and said abutment means includes radial abutments at said other axial positions arranged to engage said body and to prevent rotation thereat.  
  3. A lock as defined in claim 2, wherein said surface forms an axial groove defining an axial pathway intersecting said circumferential pathway and having opposite sides forming said radial abutments, and said abutment means includes a peripheral radial projection onto said body constructed and arranged for axial displacement into said axial pathway intermediate said opposite sides and for rotatable displacement into said circumferential pathway.  
  4. A lock as defined in claim 3, wherein said opposite sides of said axial groove form arc-shaped surfaces curving towards the bottom of said axial groove and arranged for rotational wedging of said radial projection against the same and limited rotation of said body at said other axial positions, and said internal surface forms a circumferential groove defining said circumferential pathway.  
  5. A lock as defined in claim 4. wherein each of said tumblers includes a pair of pins engaging in end-to-end abutment under the bias of said second biasing means and adapted for axial displacement of the abutting ends thereof to an unlocking position intermediate said core and said plug for rotation of the latter relative to said core.  
  6. A lock as defined in claim 5, further including an alarm circuit including an electrical alarm and a first contact member positioned adjacent the opposite face of said core relative to said one face thereof and electrically insulated therefrom. said tumbler cavities extend through said core from said one face to said other face thereof. one pin of each of said pairs of pins engages into said core and has a contact portion axially projectable outwardly from said opposite face into engagement with said first contact member and each of said one pin and said first contact member being connected to said alarm circuit and arranged to actuate said alarm upon said engagement of any of said one pins with said first contact member.  
  7. A lock as defined in claim 6, wherein said contact portion includes a reduced diameter end portion of said pin and said second spring means includes a compression spring engaged around each of said reduced diameter end portion to urge said one pin into said endwise abutment.  
 stem into abutment therewith for concomitant axial displacement of said body into said predetermined axial and unlocking position thereof.