High Security Door Lock

Abstract

A high security-unit-type, door lock having opposite side escutcheon plates which are drawn tightly against the opposite faces of the door by means accessible only from the edge of the door, so that the escutcheon plates cannot be removed when the door is closed. The lock cylinder and plug have longitudinally-spaced, radially-extending, tumbler pins therein, spring biased toward the center of the lock, the plug being formed of body end sections which are relatively rotatable for assembly at 90.degree. incremental positions. The end plugs determine the rotational position in which the key enters the lock whereby four lock combinations are provided for by relative rotation between the ends and body of the plug without changing the lengths of the tumbler pins. The lock plug directly drives bolt-extending means over-center as the plug rotates 90.degree. to prevent the bolt being pushed back into the lock from the exterior thereof. In the 90.degree. , bolt-extended position of the plug, the key may be withdrawn from the lock without rotating the plug back to its original key-insert position. The key may enter the lock from either side, using the same cylinder and tumbler pins, and the key is of cylindrical shape having straight through transverse notches milled in its outer surface spaced 90.degree. about the circumference of the key and spaced longitudinally thereof in accordance with the tumbler pin spacing.

Description

BACKGROUND OF THE INVENTION

This invention relates to the field of high security door locks using a key to both project and retract a locking bolt.

Key-operated door locks date back into antiquity with the manufacturer attempting to provide security against picking and other disabling of the locking mechanism. The present invention provides a high security lock of the unit-type having novel desirable features.

Clamping a collar against the face of a door, while pivoted to a lock housing, by the tapered end of a retainer screw where the lock is of the mortise-type, is shown in the U.S. Pat. to Forbes, et al., No. 3,455,129. Clamping of opposite escutcheon plates against the opposite faces of the door in a unit-type lock, specifically by camming or worm, gear and screw clamping means, provides structural and functional advantages thereover.

The use of a sectional lock plug bearing tumber pins spaced at uniform angles about its periphery and having end sections angularly rotatable relative thereto in the same angular increments, with the end sections limiting the rotational position of the key, provides different combinations and key changes without change in the location or lengths of the tumbler pins. This is believed to be basically new in applicants' lock construction.

The use of a cylindrical shank key is shown in the patents to Schreiber, et al., U.S. Pat. No, 3,167,943 and Schreiber, U.S. Pat. No. 3,348,392, but these use concave spherical depressions rather than the straight-through milled slots of the key of the lock of this invention.

The use of a pivoted link between a roll-back arm oscillated by an ordinary knob spindle and the tail of a bolt, is shown in the Pat. to Hurd, U.S. Pat. No. 1,687,248. However, this fails to suggest the link connection between the bolt and an arm on the cylinder plug of the lock of this invention, which is rotated over-center by an angular rotation of the plug so that the bolt cannot be pushed back into the lock from the exterior. Also, the prior art fails to show a positive bolt connection for projection and retraction, with the key removable from the plug while it is rotated angularly from its initial position; that is, it is unnecessary and undesirable to return the plug to its initial key-inserted position before the key can be withdrawn.

SUMMARY OF THE INVENTION

The door lock of the present invention provides a pleasing appearance and a rugged construction having high security features. The lock is of the unit-type inserted into a door opening extending between the opposite side faces of the door and to the free edge thereof. The lock carries opposite escutcheon plates which are drawn tightly against the opposite side faces of the door adjacent the edge thereof to close the lock opening and to hold the lock in the opening by the frictional engagement of the escutcheon plates with the door faces. The escutcheon plates are both drawn against the adjacent door faces by cammed clamping means or by worm, gear and screw clamping means which may be used together or alternatively adjacent the top and bottom of the lock.

The cammed clamping means may comprise a cam plate having oppositely inclined slots engaging pins rigid with the opposite escutcheon plates, with the can plate screw-adjusted longitudinally of the lock from the edge of the door to move the escutcheon plates transversely of the lock toward their adjacent door faces. In the worm, gear and screw clamping means, a worm accessible from the edge of the door rotates a worm wheel integral with a screw which is threaded into one escutcheon plate with the worm wheel held against transverse movement relative to the other escutcheon plate. Rotation of the worm from the edge of the door thus draws the two escutcheon plates toward each other and against their adjacent door faces. These alternative clamping means may be used together on the same lock or each may be paired with another of like kind on the same lock.

The escutcheon plate moving screws and worms above described are held against axial movement out of the lock by a working face plate mounted against the lock at the edge face thereof and having openings through which the screw and worm may be turned, but which openings are too small to permit passage of the worm and screw therethrough. A final edge face plate is mounted on the door edge in front of the working face plate to more securely hold the lock within the door edge opening and also to obscure the access means to the escutcheon plates. When the door is closed, the door edge is hidden and removal or loosening of the opposite side escutcheon plates is prevented.

The cylinder plug of the lock is preferably made with a main body and an end or end sections which may be assembled in angularly displaced positions, to be indexed in angular increments of, for example, 90.degree.. The tumbler pins are likewise located in the plug in groups at 90.degree. intervals, about its periphery and the end section or sections of the plug determine the angular position the key assumes when it is inserted therein. This construction permits four separate combinations and key shapes to be available by relative rotational assembly of the plug sections without changing the coding of the tumbler pins within the body section of the plug.

The cylinder plug is connected to the bolt by a pivoted link mounted to an arm rotatable with the plug. The construction places the link and arm over-center against a stop when the plug is rotated through the angular tumbler pin spacing, in the example 90.degree., and in this position the bolt cannot be pushed back into the lock from the exterior thereof. Indexing means is provided for releasably holding the plug in its bolt-retracted and bolt-extended positions, and with the tumbler pins similarly spaced angularly in the plug, the key may be withdrawn from the lock with the cylinder plug rotated to its bolt-extended position without requiring that the plug be rotated back into its original key-insert position. Likewise, to withdraw the bolt the key is inserted into the cylinder plug when it is in its rotated, bolt-extended position and rotation back to the original key-insert position of the plug will always withdraw the bolt because of its positive, link connection to the plug-rotated arm.

The key for operating the lock of this invention is preferably of sturdy cylindrical stock and has coding notches therein for engaging the tumbler pins, the notches being milled or cut straight across from side to side and spaced circumferentially about the shank of the key in conformance with the angular spacing of the tumbler pins in the cylinder plug. The key notches are likewise spaced longitudinally of the key shank in conformance with the longitudinal spacing of the tumbler pins in the cylinder plug.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the door lock of the present invention and its cooperating jamb;

FIG. 2 is a vertical sectional view through the lock of FIG. 1, with certain parts shown in elevation;

FIG. 3 is a front elevational view of the lock of FIG. 1 with the edge face plates removed;

FIG. 4 is a bottom plan view of the door lock of this invention;

FIG. 5 is a top plan view of the door lock of this invention;

FIG. 6 is a transverse sectional view through the lock cylinder and plug with a key in place;

FIG. 7 is a sectional view through the lock cylinder and plug on the line 7--7 of FIG. 6.

FIG. 8 is an exploded perspective view of the lock showing the plug sections; and

FIG. 9 is an elevational view of a plug end section.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a door fitted with a high security lock according to the present invention and a door jamb with a cooperating socket. The door 11 has opposite faces 12 and 13 and an edge 14. The lock is located in a cut-out opening or pocket extending from the edge 14 and including the opposite side faces 12 and 13, so there is no wood surrounding the lock proper and it is of what is known as a unit-type. The lock comprises opposite escutcheon plates 15 and 16 which are tightly drawn against the opposite faces 12 and 13 to mount and hold the lock within the door. The lock includes a bolt 17 which extends through a finish edge plate 18 into and out of a socket 19 in the door jamb 21, which has an edge face plate 22 screwed thereto and provided with an opening in front of the socket 19 to receive the bolt 17. The plate 22 is held in the jamb 21 by wood screws 23 and the lock finish plate 18 is held, inset into edge 14 of the door, by means of screws 24.

Extending through the escutcheon plate 15 is the end 25 of a lock cylinder plug which has a key indexing notch 26 communicating with a central cylindrical keyhole therein to determine the angular relationship of the inserted key to the plug end 25. If a double-ended cylinder plug is used, a similar arrangement will appear on the other side of the door extending through the opposite escutcheon plate 16.

Referring more particularly to FIGS. 2 and 5, escutcheon plates 15 and 16 have opposed interiorly projecting lugs 27 and 28 above which is mounted for rectilinear movement, a cam plate 29 having an internally threaded forward boss 31 receiving a screw 32 which passes freely through an axial opening 33 in a transversely extending projection 34 adjacent the front of the escutcheon plate 15. The head 35 of the screw 32 is received in a clearance pocket in the front face of the projection 34, where it is retained by a holding plate 36 mounted against the front face of the projection 34 by screws 40. The holding plate 36 has an opening 37 therethrough in alignment with the screw 32 but smaller than the head 35, so that it holds the screw against axial movement relative to the projection 34 while permitting access of a tool to the head 35 to effect turning of the screw. Turning of the screw 32, which is threaded into the boss 31, will thereby effect rectilinear movement of the cam plate 29 longitudinally of the lock. The cam plate has oppositely inclined slots 38 and 39 therein, which respectively receive pins 41 and 42 rigidly mounted in the lugs 27 and 28, which are integral with the escutcheon plates 15 and 16.

As the cam plate 29 moves longitudinally of the lock, the pins 41 and 42 in the slots 38 and 39 will be moved toward or away from each other according to the direction of movement of the cam plate. In FIG. 5, the central arrow indicates movement of the cam plate toward the front of the lock, in which case the slots converge relative to the pins 41 and 42 which are thereby moved toward each other as indicated by the transverse arrows in FIG. 5. This action forces the escutcheon plates 15 and 16 toward each other into rigid, frictional engagement with the opposite faces 12 and 13, respectively, of the door, thereby securely holding the lock mechanism within the door. The top of FIG. 2 and FIG. 5 illustrate but one form of escutcheon plate moving means, it being understood that rotation of the screw 32 in the opposite direction to that of FIG. 5 will move the cam plate 29 back and separate the escutcheon plates 15 and 16 from the door faces for removal of the lock. Thus, the lock can be removed from the door only from the edge 14 thereof and neither escutcheon plate can be loosened nor removed when the door is closed.

In the bottom of FIG. 2 and in the bottom plan view of FIG. 4 is shown another method of moving the escutcheon plates into and out of clamping engagement with the door faces. It will be understood that in the same lock, the separate operating means illustrated at the top and bottom of FIG. 2 may be used, as therein shown. Alternatively, operating means of the same type can be used at both the top and bottom of the lock. The operating means of FIG. 4 comprises a long shank worm 43 having a head 44 in a pocket in the front face of the projection 34 in which it is held by the plate 36 in the same manner as the head 35 of screw 32. The worm 43 is freely rotatable within the opening 45 in the projection 34, and its interior end is threaded at 46 to mesh with a worm wheel 47 integral with a screw 48 threaded into a boss 49 projecting inwardly of the escutcheon plate 16. The screw 48 is prevented from moving axially within the projection 34, so that rotation of the worm 43 will rotate the worm wheel 47, thereby rotating screw 48 and moving the boss 49 and escutcheon plate 16 transversely relative to the escutcheon plate 15.

The plate 36 has an opening 51 (FIG. 2) therethrough aligned with the worm 43 and smaller than its head to prevent withdrawal of the worm 43 while the plate 36 is in place but permitting a tool to enter the opening 51 and engage the head 44 to turn the worm 43. As the worm 43 turns in one direction, the escutcheon plates 15 and 16 move toward each other into rigid clamping engagement with the opposite faces of the door to hold the lock in place. Again, the screw 43 may be rotated to loosen the escutcheon plates 15 and 16 only from the front edge of the door and after the finish plate 18 has been removed.

When the lock is in place in the door, the finish plate 18 is inset into the front edge 14 in front of the holding plate 36 to finish the front of the lock, the wood screws 24 extending through both plates 18 and 36. These plates have suitable openings therethrough of a size to closely embrace the lock bolt 17. The inside face of the projection 34 has a rectangular recess 52 (FIG. 3) therein which receives the bolt 17 for sliding movement longitudinally of the lock, and the recess 52 is closed to hold the bolt 17 therein by a side plate 53 (FIG. 5) secured to the projection 34 by a screw 54.

A lock cylinder 55 is bolted to the inner face of the escutcheon plate 15 by studs 56 and has a cylinder plug 57 extending therethrough and having opposite end sections 25 and 25A extending, respectively, through the escutcheon plates 15 and 16 in the double-sided version of the lock. In the single-sided version, the end section 25 of the lock may be omitted and the escutcheon plate 15 made imperforate whereby access by the key into the lock can be had only through end section 25A and the escutcheon plate 16.

The lock cylinder 55, as shown more clearly in FIG. 8, has a relatively large, generally circular portion 58, by which it is connected to the escutcheon plate 15, and four longitudinally and radially extending wing sections 59 - 62, four in number and spaced circumferentially of the lock cylinder spaced 90.degree. apart. The interior ends of the wing portions 59 - 62 are interconnected by part cylindrical portions 63 which are integral with them and with the circular portion 58. In the circular portion 58 and the wing sections 59 - 62 of the lock cylinder, there are disposed groups of a plurality, here illustrated as five, radially extending and longitudinally spaced tumbler pin bores 66, in which are reciprocally mounted top outer, generally cup-shaped tumbler pins 67 having biasing 68 therein which bear against outer retaining strips 69 to bias the outer pins toward the center of the lock cylinder. The retaining strips 69 have dove-tail connections with the outer ends of the wings 59 - 62, so that only sliding movement axially of the lock cylinder is permitted to remove the retaining strips when the lock is disassembled. The bores 66 are spaced axially of the lock cylinder, that is, transversely of the lock proper, and they are mounted in groups which are spaced angularly about the lock cylinder, as illustrated in FIGS. 7 and 8, a uniform 90.degree..

The cylinder plug 57 is mounted coaxially within the lock cylinder 55, fitting its inner cylindrical surface 64 which, adjacent the tumbler pin bores, provides shear lines at 65 between the inner and outer pins forming the lock tumblers. In the double-sided entry lock form of FIG. 6, the cylinder plug comprises a center body section 71 and opposite end sections 25 and 25A. The end section 25 has the key indexing notch 26 previously recited, and the end section 25A has a key indexing notch 26A. The body section 71 of the plug has a plurality of radially extending and axially spaced bores 72 therethrough which align with the bores 66 in the lock cylinder, the bores 72 being also spaced circumferentially at 90.degree. intervals, as shown more particularly in FIG. 7. Within the bores 72 are the inner tumbler pins 73 having spherically rounded internal ends 74 cooperating with the key notches. The outer ends of the inner tumbler pins 73 may be made slightly curved or spherical where they engage the flat bottoms of the outer tumbler pins 67. It will be apparent from an inspection of FIGS. 6 and 7 that when the junctions of the outer and inner tumbler pins are all at the shear line 65, being moved thereto by the configuration of the coding notches on the key 75, the lock plug may be rotated within the lock cylinder by the key.

The circular portion 58 of the lock cylinder is provided with an indexing ball 76 (FIG. 7) biased toward the center of the lock cylinder by a spring 77 retained by a screw 78. The figures illustrate the lock in the bolt-retracted position, and in that position the ball 76 is indexed into a spherical depression 79 in the outer surface of the plug body section 71. A second spherical indexing depression 81 in the peripheral surface of the plug body section 71 is located angularly spaced 90.degree. from the depression 79 and indexes with the ball 76 when the cylinder plug is in bolt-extended position, thereby insuring alignment of the lock cylinder bores 66 with the cylinder plug bores 72 so that the key 75 may be withdrawn from the rotated plug, the tumbler pins passing freely past the shear line 65 as the key is withdrawn and its coding grooves and hills move the different length inner tumbler pins 73 within the bores.

A bolt-operating arm 82 is keyed by an integral central portion 83 (see FIG. 6) onto the center section 71 of the cylinder plug and is held thereon by a split ring 84 against movement axially of the plug. This also locates that end of the center section 71 of the plug relative to the adjacent end of the lock cylinder 55. The opposite end of the center section 71 of the cylinder plug is located relative to the opposite end of the lock cylinder 55 by a split ring 85. The free end of the arm 82 carries a spacer 86 toward the center plane of the lock and lock cylinder where a link 87 is pivotally mounted, being held thereon by split ring 88. The opposite end of the link 87 (see FIG. 2) is pivotally mounted to the sliding bolt 17 and 89, the link 87 extending into a slot 91 running vertically across the back of the bolt and within which the link extends for swinging movement from the full line position of FIG. 2, with the bolt retracted, to the dotted line position thereof, with the bolt extended.

The end sections 25 and 25A of the cylinder plug are interlocked with the center section 71 for relative rotation and reassembly in 90.degree. angular increments. The illustrated means for accomplishing this are a pair of pins 92 secured at the opposite ends of the center section 71 of the plug to enter cooperating blind holes 93 (see FIGS. 6 and 8) in the inner faces of the end sections 25 and 25A. There are four holes 93 spaced 90.degree. apart so that the ends 25 and 25A have four different positions for assembly on the center section 71 spaced 90.degree. apart. The location of the pins 92 and the holes 93 is such that when the end sections 25 and 25A are assembled on the center section 71, the indexing notches 26 and 26A will be aligned with a group or row of holes 72 in the cylinder plug which receive the tumbler pins. These four positions mean that four separate codings or combinations of the lock cylinder and plug may be secured by effecting relative rotation of the end and center sections, without changing the locations or lengths of the inner tumber pins 73. It will be noted that all of the outer tumbler pins 67 have the same length for standardization, while the inner tumbler pins vary in length to establish the lock combination.

Where the same key is to be used from opposite sides of the lock, it will, of course, be understood that the tumbler pins must be symmetrical in their lengths from each side toward the center of the lock, which somewhat cuts down on the attainable combinations. On the other hand, if the lock is entered from a single side or with a different key from each side, the possible combinations increase enormously since the opposite side tumbler pins may in that case be unique.

The keyhole in the cylinder plug is substantially cylindrical, as shown more particularly in FIG. 7, and the key 75 has an initially cylindrical shank 94 with an integral flat operator 95 having an integral projection 96 indexing in the notches 26 and 26A. The shank 94 is provided with a plurality of grooves 97 which are spaced apart longitudinally of the shank in conformance with the spacing between the tumbler pin bores 72, so that the ends of the inner tumbler pins will engage in the slots 97 in the inserted position of the key 75, as shown more particularly in FIG. 6. With the proper coded depths of the grooves 97 in the key 75, the tumbler pins assume positions where the junctions between the outer and inner pins are all at the shear line 65 of the cylinder, so that the plug may be turned therein.

The grooves 97 are provided on four sides of the shank of the key, spaced 90.degree. apart around the circumference in accordance with the spacing shown in FIG. 7 for the groups of tumbler pin bores 66 and 72. In this arrangement, with the key properly inserted so as to index projection 96 with the notch 26 or 26A, a series of grooves 97 will be presented to each of the four groups of inner tumbler pins 73, again as shown in FIG. 7.

For ease of insertion of the key 75 into the keyhole, the end thereof may be generally pointed at 98 and provided with inclined notches 99, one aligned with each group of inner tumbler pins. The ends of the bottom tumbler pins successively enter the notches 99 to be moved outwardly by the key and also to guide the key so that it is indexed in its initial insertion with each series of grooves 97 aligned with a group of inner tumbler pins 73. A subsidiary feature of the invention lies in the formation of the grooves 97 which are cut or milled straight through, transversely of the shank 94 of the key 75, and are more easily and accurately formed than drilled depressions which receive the ends of the inner tumbler pins.

In mounting the lock of the present invention in the door 11, a rectangular pocket is cut in the front edge of the door which is entirely open at both the opposite faces of the door and at the front edge thereof. The front edge of the door is then inset so as to receive the plates 36 and 18 with the latter flush with the edge surface. The escutcheon plates 15 and 16 are separated wider than the thickness of the door by manipulating the screw 32 and the worm 43 and the main body of the lock is inserted from the front into the rectangular pocket, with the side escutcheon plates 15 and 16 slightly spaced from the side faces 12 and 13 of the door. The lock is inserted until the plate 36 thereon seats against the front face of its inset recess and the screw 32 and the worm 43 are rotated through the openings 37 and 51 to draw the escutcheon plates 15 and 16 tightly against the opposite faces 12 and 13, respectively, of the door, thereby tightly securing the lock within the door, a condition from which it can be loosened only by access to the edge of the door which is hidden when the door is closed.

As the screw 32 is rotated through opening 37 to draw the cam plate 29 toward the front of the lock, pins 41 and 42 slide down the slots 38 and 39 and are drawn together, as indicated by the small arrows in FIG. 5, thus pulling the adjacent portions of the escutcheon plates 15 and 16 tightly against the side faces of the door. If it is desired to remove the lock at any time, reverse rotation of the screw 32 will move the cam plate in the opposite direction to separate the pins 41 and 42 and loosen the escutcheon plates from their tight engagement with the faces of the door. As the worm 43 is turned by engagement through the opening 51, the threaded portion 46 rotates the worm wheel 47 clockwise, as viewed in FIG. 2, whereupon the screw 48 draws the boss 49 toward worm wheel 47, thereby pulling the escutcheon plates 15 and 16 tightly together against the opposite faces 12 and 13 of the door.

As previously pointed out, the lock can be made with the different escutcheon plate moving means, as shown in FIG. 2, or it can be constructed with cam plates 29 both at the top and bottom of the lock or with worm and wheel operation of the escutcheon plates at both the top and bottom of the lock. Variations on these two methods will be readily apparent from a knowledge of mechanical movements, the essential feature being that access to the manipulating means is secured only from the front edge of the door which is hidden when the door is closed. Therefore, the escutcheon plates and lock cannot be loosened nor removed unless the door is open.

When the escutcheon plates 15 and 16 have been tightened against the side faces of the door to tightly hold the lock in position, the finish plate 18 is placed in front of the working plate 36 and held there by the wood screws 24, with the plate 18 thereby covering the screws 40 and the openings 37 and 51.

The lock may be mounted in the door to permit entrance of an operating key from either side in the manner illustrated in FIG. 6. Conversely, the end section 25 may be closed to have no keyhole therethrough or it may be entirely omitted or made integral with the center plug section 71, and, entrance may be had only through plug end section 25A. In the case of key entrance from both sides, the inner tumbler pins 73 may be symmetrical from the opposite sides toward the center so that the same key may be used from either side to operate the lock. On the other hand, still with entrance to the keyhole from both sides, the inner tumbler pins can be made asymmetrical with respect to the opposite sides whereby different keys will be required to operate the lock from different sides. The arrangement, therefore, readily lends itself to a number of variations of cylinder plug construction and key operation.

With the tumbler pin bores 66 and 72 uniformly distributed in groups around the circumference of the lock cylinder, as illustrated in FIG. 7 four groups spaced 90.degree. apart, and with the cylinder plug formed in sections which are similarly relatively positionable through the same angular distance as the spacing between the groups of tumbler pins, in the illustrated case 90.degree., and with the angular position of the key indexed with respect to the cylinder plug end sections, as by the projection 96 and the notches 26 and 26A, separate combinations or codings of the lock equal in number to the number of groups of tumbler pins, in the instant case, four, may be provided in the lock without changing the individual tumbler pins. The center and end section or sections of the plug are angularly offset to align the notch 26 or 26A, or both of them, with different groups of the tumbler pins, whereupon a different key will be required to operate the lock for each such angular offset of the plug sections, since the tumbler pins in each group are unique. Therefore, in the illustrated embodiment, four separate and distinct combinations of the lock requiring four different keys are coded by relative rotation and reassembly of the cylinder plug sections through 90.degree. increments, as illustrated, by cooperation of the pins 92 with different sets of holes 93. This is accomplished without changing the locations or lengths of any of the individual inner tumbler pins 73 in the center section of the plug.

In operating the lock, the key 75 is pushed into the keyhole until the projection 96 is stopped at the end of its indexing notch, such as 26A. At this time, the ball 76 is in the depression 79 so that the plug 57 is indexed with the bores 72 aligned with the cylinder bores 66. In its unseated position, the grooves 97 on the key will be aligned with the bores 72 to receive the ends of the inner tumbler pins 73. If the depths of the key grooves correspond to the lengths of the inner tumbler pins 73, the junctions between the outer and inner tumbler pins will occur at the shear line 65 of the cylinder, as illustrated in FIGS. 6 and 7, so that the cylinder plug may be turned in the cylinder. As the plug is turned, counter-clockwise as viewed in FIGS. 2 and 7, the operating arm 82 rotates therewith and, through the pivoted link 87, drives the lock bolt 17 to its projected position, shown in dotted lines in FIG. 2.

In this position, the cylinder plug will have rotated through a full 90.degree. and the depression 81 receives the ball 76 to index the bores 72 in alignment with bores 66 spaced 90.degree. from the original groups with which they were aligned. The key 75 may, therefore, be withdrawn from the keyhole in this 90.degree. rotated position with the bolt extended and without returning the plug to its original position, since the tumbler pins may pass freely through the shear line of the cylinder. In this full 90.degree. rotation of the cylinder plug, the pivotal connection between the link 87 and the arm 82 moves over-center, as shown in dotted lines, so that the bolt 17 cannot be pushed back into the lock from the exterior thereof, the arm 82 being prevented from further rotation in the same direction by its engagement with a stop lug 101 on a fixed part in the lock, such as on the projection 34.

To retract the bolt, the key is reinserted in the keyhole in the position spaced 90.degree. from its originally inserted position and is then rotated back in a clockwise direction, as shown in FIG. 2, whereupon the arm 82 rotates back to its initial position, pulling the link 87 and the bolt 17 therewith into the full line position of FIG. 2. The depression 79 again receives the ball 76 to index the cylinder plug with its tumbler bores 72 aligned with the bores 66 in their original positions, and the key may be withdrawn, the inner tumbler pins 73 again freely moving through the shear line of the cylinder.

While certain preferred embodiments of the invention have been specifically illustrated and described, it will be understood that the invention is not limited thereto as many variations will be apparent to those skilled in the art, and the invention is to be given its broadest interpretation within the terms of the following claims.

Claims

What is claimed is:

1. A door lock comprising:

a lock body adapted to be mounted in a door adjacent the front edge thereof;

a lock bolt;

means mounting said lock bolt for projection and retraction movements relative to the front edges of the lock and door;

key-controlled means for projecting and retracting said bolt;

escutcheon plates on opposite sides of said lock body and having surfaces extending therebeyond to be engageable with the opposite faces of the door;

positioning means between said escutcheon plates connected thereto to hold said plates in a preselected spaced relation, and oppositely operable to positively move said plates alternately closer together and farther apart; and

means accessible only from the front edge of the door for operating said positioning means to move said escutcheon plates into and out of clamping engagement with the opposite faces of the door.

2. The lock defined in claim 1 in which said escutcheon plate positioning and operating means comprise:

cam means movable toward the front and back of said lock body;

screw means accessible only from the front edge of the door for moving said cam means;

two oppositely inclined sets of camming surfaces on said cam means; and

means on said escutcheon plates engageable respectively with said oppositely inclined cam surfaces for moving the escutcheon plates both into and out of clamping engagement with the opposite faces of the door upon movement of said cam means forwardly and rearwardly of the lock.

3. The lock defined in claim 1 including:

a first front edge plate removably secured to the lock body;

openings through said first edge plate aligned with the means accessible only from the front edge of the door to provide manipulating access thereto, said openings being smaller than said means to prevent removal thereof while said edge plate is in place; and

a finish front edge plate attachable to the front edge of the door and covering said first front edge plate to cover the openings therethrough and the attachment means therefor.

4. The lock defined in claim 1 in which said key-controlled means comprises:

a lock cylinder;

a cylinder plug rotatably mounted in said lock cylinder;

tumbler pin bores extending through said lock cylinder and cylinder plug, said bores extending radially and being spaced longitudinally of the lock cylinder and plug and in groups circumferentially thereof at uniform angular spacings so that the bores in the cylinder and plug align in several angularly relative positions of said cylinder and plug;

an arm mounted on said plug to be rotated therewith;

a key insertable in said plug to rotate it;

a link pivotally interconnecting said arm and said bolt for projecting and retracting it, the bores in said plug in the projected position of said bolt aligning with the next angularly adjacent group of bores in the cylinder so that the operating key may be withdrawn from the plug in the rotated position thereof and without returning to the initial key-inserting position;

said cylinder plug having an end section at one of said plates mountable on the plug in different angular positions spaced apart by increments of the uniform spacing angle between said groups of tumbler pin bores;

and means for securing said end section to said plug in said different angular positions;

said end section having key-indexing means thereon for receiving a key in a preselected angular relationship with said end section, whereby different angular relationships between said cylinder plug and said end section produce different lock combinations equal in number to the number of groups of bores, without changing the individual tumbler pins within the plug.

5. The lock defined in claim 4 in which said groups are four in number, spaced 90.degree. apart, and said plug sections may be assembled in four different angular relationships, 90.degree. apart, to give four different lock combinations without changing the individual tumbler pins.

6. The lock defined in claim 4 in which:

said cylinder plug has a cylindrical keyhole therein,

said operating key for the lock has a cylindrical shank insertable in said keyhole; and

coding grooves in said key shank cut straight through from side to side in a series spaced longitudinally of the key in accordance with the tumbler pin bore spacing and disposed in groups spaced circumferentially of the shank at angular distances corresponding to the angular spacing between the groups of tumbler pin bores so that the coding notches will align with the tumbler pins in their bores after the key is inserted into the keyhole.

7. A door lock comprising:

a lock body adapted to be mounted in a door adjacent the front edge thereof;

a lock bolt;

means mounting said lock bolt for projection and retraction movements relative to the front edges of the lock and door;

a lock cylinder;

a lock plug rotatably mounted in said lock cylinder;

means interconnecting said cylinder plug and lock bolt for movement of the latter as the cylinder plug is rotated;

tumbler pin radial bores in said lock cylinder and cylinder plug spaced longitudinally thereof and in groups circumferentially in uniform angular relations, said cylinder plug having relatively angularly shiftable end and body sections which may be assembled in different positions angularly spaced by the uniform angular distance between said bore groupings and equal in number to the number of said groups:

means for securing said end section to said body section in said different positions; and

means on said end section for admitting a key into said plug in a preselected angular relationship with said end section, whereby to provide different combinations equal in number to the number of said groups by shifting the relative angular positions of the end and body sections of the cylinder plug but without change in the individual tumbler pins in the body section of the plug.

8. The lock defined in claim 7 in which said groups are four in number spaced uniformly 90.degree. apart and in which the end section is associated with the body section of the plug in four different positions, likewise spaced 90.degree. apart, to provide four different combinations of the lock without changing individual tumbler pins.

9. The lock defined in claim 7 in which:

the key hole through said cylinder plug is of cylindrical shape, and further including:

an operating key for said lock having a cylindrical shank fitting said keyhole, and straight through grooves in its periphery spaced longitudinally in accordance with the longitudinal spacing between tumbler pin bores in the cylinder plug and spaced circumferentially in groups according to the angular spacing between the groups of the tumbler pin bores.

10. A door lock comprising:

a lock body adapted to be mounted in a door adjacent the front edge thereof;

a lock bolt;

means mounting said lock bolt for projection and retraction movements relative to the front edges of the lock and door;

key-controlled means for projecting and retracting said bolt;

escutcheon plates on opposite sides of said lock body and having surfaces extending therebeyond to be engageable with the opposite faces of the door;

a cam plate disposed between said escutcheon plates and supported for back and forth movement toward the front and back of said lock body, said cam plate having oppositely inclined slots therein;

a pin on each of said escutcheon plates extending into one of said slots and engageable with the opposite side walls thereof during back and forth motion of said cam plate, whereby said plate acts through said pins to draw said escutcheon plates together in one direction of movement of said cam plate and to spread said escutcheon plates apart in the opposite direction of movement of the cam plate; and

means accessible only from the front edge of said lock body for moving said cam plate back and forth.

11. A door lock comprising:

a lock body adapted to be mounted in a door adjacent the front edge thereof;

a lock bolt;

means mounting said lock bolt for projection and retraction movements relative to the front edges of the lock and door;

key-controlled means for projecting and retracting said bolt;

escutcheon plates on opposite sides of said lock body and having surfaces extending therebeyond to be engageable with the opposite faces of the door;

means accessible only from the front edge of the door for moving said escutcheon plates into and out of clamping engagement with the opposite faces of the door;

said means for moving said escutcheon plates comprising:

a worm gear extending longitudinally of the lock and having an operating head accessible only from the front edge of the door;

a worm wheel mounted for rotational movement only in means rigid with one of the escutcheon plates; and

screw means rotatable by said worm gear and threaded into the other of said escutcheon plates, whereby rotation of the worm gear rotates said worm wheel and screw means to move said escutcheon plates relative to each other transversely of the lock into and out of clamping engagement with the opposite faces of the door.

12. The lock defined in claim 11 in which said worm wheel is co-axially mounted adjacent the end of said screw means opposite to that threaded into said other escutcheon plate and in which said screw means and worm gear are both mounted for rotation in said one escutcheon plate.

13. A high-security door lock mountable in a notched edge of a door, and comprising:

a pair of escutcheon plates disposed in spaced apart relation and having adjacent faces for engaging opposite faces of the door around the notch therein, at east one of said escutcheon plates having an opening therein of preselected size;

a lock cylinder having a cylinder plug rotatably mounted therein, at least one longitudinal row of tumbler pin bores extending radially through said cylinder and said plug, and tumbler pins in said bores, said cylinder being disposed entirely between said escutcheon plates with one end of said plug aligned with said opening to receive a key therethrough, and being fixedly mounted on one of said plates;

positioning means between said escutcheon plates connected thereto to hold said plates in a preselected spaced relation and oppositely operable to positively move said plates alternately closer together and farther apart; and

means accessible only from the side of said lock that extends along the edge of the door when the lock is mounted in the notch, for operating said positioning means to move said escutcheon plates into and out of clamping engagement with the opposite faces of the door.

14. A high-security door lock as defined in claim 25 in which said cylinder is fastened to the inner side of one of said escutcheon plates for movement therewith toward and away from the other escutcheon plate, and is spaced from said other plate prior to clamping of the plates against the door.

15. A high-security door lock as defined in claim 14 in which said cylinder plug has a coaxial end section secured to said one end of said plug and extending rotatably through said opening, said end section having an inner end portion larger than said opening positioned inside and other escutcheon plate to abut against the latter.

16. A high-security door lock as defined in claim 15 in which said end section is secured to said cylinder plug by means of pins parallel to the axis of said cylinder plug and extending into both said plug and said inner end portion.

17. A high-security door lock as defined in claim 13 in which said escutcheon plates are formed with aligned openings and said cylinder is mounted between said plates with one end of said plug adjacent each of said openings, and further including a separable end section secured to each end of said plug and extending rotatably into the adjacent opening, at least one of said end sections having a hole therethrough for admitting a key into said plug.

18. A high-security door lock as defined in claim 17 in which each of said end sections has an enlarged inner end portion larger than the adjacent escutcheon plate hole and disposed inside the escutcheon plate to block removal of the end section through the hole.

19. A high-security door lock as defined in claim 18 in which said end sections are secured to the ends of said plug by means of pins parallel to the axis of the plug.

20. A high-security door lock mountable in a notched edge of a door, and comprising:

a pair of spaced, side-by-side escutcheon plates having adjacent faces for engaging opposite faces of the door around the notch therein, said escutcheon plates being imperforate except for a pair of aligned openings through the plates;

a lock cylinder disposed entirely between said plates and having a cylinder plug rotatably mounted therein, the ends of said plug being aligned with said openings and said cylinder being fixedly mounted on one of said escutcheon plates;

means lying entirely between said plates holding the latter together in a unit and selectively operable to draw the plates together and to move them farther apart;

and means accessible only from the side of said lock that extends along the edge of the door when the lock is mounted in the notch, for operating said holding means to move the plates into and out of clamping engagement with the opposite faces of the door.

21. A high-security door lock as defined in claim 20 further including a pair of detachable end sections coaxially mounted on the opposite ends of said cylinder plug and extending rotatably into said openings, at least one of said end sections having a passage therethrough for admitting a key into said cylinder plug.

22. A high-security door lock as defined in claim 20 in which the last-mentioned means include at least one screw actuator having a head adjacent said side of said lock and extending inwardly to said holding means.

23. A high-security door lock as defined in claim 22 in which said holding means are located approximately midway between said side and the opposite side of the lock, to clamp said escutcheon plates centrally against a door.