US2166690A - Lock - Google Patents

Description

I July 18, 1939- w. R. NECKERMAN LOCK Filed June 11, 1938 INVENTOR a %l dnmw ayw/ww Patented July 18, 1939 UNITED STATES FATENT OFFICE 4 Claims.

My invention relates to locks of the pin-tumbler construction, and consists in refinements in structure, by virtue of which the lock is safeguarded against fraudulent opening, either by picking or by the impression system.

In the accompanying drawing a lock embodying the invention is illustrated. Fig. I is a View of the lock in front elevation; Fig. II is a view of the lock in rear elevation, with a portion of the rear cover-plate broken away, to show the organization of the lock bolts within; Fig. III is a view in side elevation of the key used to operate the lock; Fig. IV is a view showing the lock structure partly in side elevation and partly in axial section, on the plane IV--IV of Fig. II; Fig. V is a sectional view of the lock on the plane V-V of Fig. IV; Fig. VI is a view in side elevation of a particular element of the lock structure; Fig. VII is a view comparable with Fig. V, showing certain elements of the lock in alternate positions of operation; Fig. VIII is a fragmentary view, showing on larger scale the internal construction of the lock partly in axial section and partly in side elevation; and Fig. IX is a View on still larger scale, showing one of the tumbler-pins of my lock in side elevation.

The lock in which the invention is found consists of a cylindrical barrel, a cylindrical plug, and one or more lock bolts. The plug is rotatable in the barrel for moving the lock bolt inward from extended or locking position. Both the barrel and the plug are formed with radially extending bores in which tumbler-pins are arranged; the bores in the barrel are adapted to be aligned one with each of the bores in the plug, and the pins in the aligned bores meet end to end. In the pin-receiving bores, helical springs are severally arranged, and these springs, urging the paired pins towards the radially inner ends of the bores, serve yieldingly to maintain the pins in such positions that one pin of each pair stands with its body partly in the bore in the plug and partly in the bore in the barrel. (In the parlance of the art the pins are said to extend across the shear-line between barrel and plug.) In consequence the plug normally cannot be rotated within the barrel to operate the lock.

The plug is adapted to receive a key, and when such key is inserted, it operates in well-known manner to adjust and hold the paired pins with their meeting ends flush with the meeting surfaces of the plug and the barrel. In consequence the plug may be rotated upon the turning of the key, and the lock bolt moved into release position.

Referring to the drawing, I have shown the lock embodied in a cylindrical metal block I which in service forms the closure for an opening 2 in a wall 26, Fig. IV. (The wall 26 will be understood to be the heavy metal wall of a safe, or a coin-box, or other such enclosure.) The block I includes a cylindrical bore 3, and forms the barrel of the lock. The cylindrical plug 4, rotatably mounted in bore 3, is secured against axial displacement in such bore, by means of a peripheral shoulder 40 (Fig. IV) integral with the plug, and the peripheral edge of a disk 5 rigidly secured to the plug, by means of screws 56. The lock includes a plurality of radially extending bolts 6 which, in response to rotation of the plug t in opposite directions, are movable inward and outward. When the lock is in service the bolts are locked in extended positions, securing the block I in the opening in wall 20, as shown in Fig. IV. And when as described below, the bolts are drawn radially inward, the block may be removed from position of closure in such opening.

The lock includes a plurality of paired tumblerpins a and b. The pins of each pair are axially aligned in radially aligned bores c and 01 formed in the barrel and plug, respectively. In this case, I provide six sets of plunger-pins; there are two pairs of pins in each set extending in common plane radially of the assembled plug and barrel, as shown in Figs. IV and VIII, and the six sets of pins are angularly spaced at -degree intervals with respect to the axis of the plug 4. (Note the arrangement of the pin-receiving bores c and d, indicated in dotted lines in Fig. V.) A cylindrical keyway 8 is formed in the plug, and a stem 9, carried by the disk 5 that is rigid with the plug, extends in the keyway on the axis of the assembly. Extending radially from the keyway is a slot 7 for each radial set of plunger-pins; the slots 1 open through the lower or inner ends of the pin-receiving bores d in the plug 4, and such slots are adapted severally to receive properly patterned key-blades, which blades cooperate in known way with the inner ends of the pins b in the plug, to adjust the paired pins a and b in shear positions, so that the plug may be rotated within the barrel. Thus, when the proper key is introduced into the lock, the plug 4 may be rotated, and as will presently appear, such rotation of the plug is effective to shift the lock bolts 6.

The-structure of the key for the lock will be readily understood. It consists in a body It in the form of a cylindrical tube adapted to slide over the stem 9 and fit snugly in the cylindrical keyway 8 in the plug. The body ll] of the key carries six rigid blades H, angularly spaced to enter, one in each, the six radial slots 1 in the plug, and each blade is shaped to proper pattern at its outer edge, to operate the tumbler-pins in the manner already described. The key is provided with a head l2 of usual sort, and reinforcement of the blades and head with body If! is provided in the form of an integral frusto-conical body I3.

Turning to a consideration of the particularly effective organization of the lock bolts in the structure, attention is directed to Fig. II. The body of the block I is provided with four radially extending channels l4, and in these channels the lock bolts 6 are severally confined, by means of a cover-plate 15 secured (by screws IE) to the body of the block. The bore 3 in the block is radially enlarged, providing a circular recess 30 in which the disk 5 is arranged, and in this recess a disk-like member I! is assembled face to face with the disk 5. Save as hereinafter described, the member I"! is rotatable independently of the rigidly integrated disk 5 and plug 4; the outer surface of the rotary member I! extends in common plane with the floors of the channels M in the block I the lock bolts 6 consist of plate-like bodies of the form shown; they lie fiat against the floors of the channels and the outer face of the member l1; and they extend in substantially radial direction inward from the channels I4, and are severally pivoted to the member I1. More specifically, the rotary member I! is provided with four rigid pins l 8 that extend outward from the face of the member and are symmetrically arranged eccentrically of the axis of the lock structure. The radially inner end of each lock bolt is perforated and assembled upon one of the pivot pins I 8, as shown. Manifestly, the organization is such that rotation of the member I! in counter-clockwise direction (Fig. II) shifts the bolts inward'in substantially radial direction into such position that the lock structure may be removed from the wall in which it is secured. (Note the broken-line position 6a of one of the bolts in Fig. II.) Rotation of the member I! in opposite direction is effective to move the bolts outward into extended or looking position. The lock structure includes means for rotating the bolt-shifting member I! in response to rotation of the plug '4, and it is important to note that such means consist in a lost-motion device.

Referring particularly to Figs. V to VIII, it will be perceived that an arcuate slot or way I9 is formed in the plug 4, in this case in the disk 5 integrated with such plug, and into this slot extends a pin 2!) that is rigid with the member H. As may be observed in Fig. V, the arcuate slot I9 extends angularly of the axis of the plug through a greater interval than the angular interval between the two radial sets of plungerpins contained in bores c, d and c", d". When the plug is locked against rotation by the tumbler-pins, the positions of the parts are as shown in Fig. V, it being noted that the body of the disk 5 at the end l9a of the slot bears against a detent in the form of a pin 2| extending from the body of the block I into the slot. When the lock structure is thus locked, the bolts 8 are extended, and pin 20 on the member I1 is positioned at the end I9a of the slot.

When the key is inserted in the lock and the plug 4 rotated (counter-clockwise, as viewed in Fi th o a qe o the p us ca e e bo y of disk 5 at the end l9b of the slot into lateral abutment upon the pin 20, and, rotation of the plug continuing through a predetermined interval when such abutment of the parts has been established (Fig. VII), the member I! is rotated and effects movement of the lock bolts 6 into retracted positions. It will be observed that the body of the disk 5 is circumferentially recessed, as at 22, so that, when the end lSb of of the slot has been brought to abutment upon pin 20, the periphery of disk 5 will clear the detent 2|, and permit rotation of the parts through an angular interval equivalent to the arcuate extent of circumferential recess 22-the interval required to obtain movement of the lock bolts from extended to retracted positions. Thus it is that the slotand-pin organization I 9, 26 provides a lost-motion connection between the plug 4 and the boltshifting member l1, and it is by virtue of such organization that the plug must be rotated, first through an angle greater than the angle between the sets of tumbler-pins in bores c, d and c, d to bring portions I91) and 20 into abutment, and then through an additional but relatively small angle to effect the movement of the lock bolts. In order to open 'the lock by picking, it is necessary to pick the pins in the six sets of bores (c, d-c, d'c", d"-etc.), and this is a very difiicult, if not impossible, thing to do. But assuming that it can be and is done, the plug 4 is released for rotation in bolt-retracting direction. It will be understood "that before the portion 9b of the member I! can move into lock-operating abutment upon the pin 20,-the tumbler-pins or driver-pins b in the bores d in the plug must pass across the mouths of the tumbler-pin bores c in the barrel; the pins in bores d must pass across the mouths of the bores in the barrel next succeeding the bores c in counter-clockwise direction '(Fig. 'V); and so the pins in each bore in the plug must pass across the mouths of succeeding bores in the barrel. However, as soon as the pins in the angularly moving plug come to alignment with the said succeeding bores in the barrel, the pins in the barrel, under the force of their springs, move against the pins in the plug and'shift them out ofthe shear positions in which they were set by picking. Thus, the plug, in course of its movement into bolt-retracting position, is arrested and becomes lockedf in an intermediate position. Those in the art will readily perceive that it is practically impossible to pick a lock constructed and operated in this way.

The look structure, as thus far described, is manifestly difiicult to open by the impression systema well-known system or method of opening looks that has been widely practiced on looks that include one set of tumbler-pins. (The method is also applicable to looks of hitherto known structures including several radially extending sets of pins.) Briefly, such method consists in inserting a blank key in the lock; then applying rotative stress to the key, in such manner that the tumbler-pins extending acrossthe shear-line between the plug and barrel are subjected to shearing stress; and then, while the parts are under such stresses, axially reciprocating the key through a small interval. In this way the inner ends of the driver-pins mark impressions on the edge of the blank key blade. The key is withdrawn from the lock and in the regions indicated by the impressions notches are filed in the edge of the blade, not much more than enough to eradicate the impressions. Then the key is reintroduced to the lock and the operations are repeated. Time and again the operations are repeated, until the blade of the key is brought to proper form to operate the lock. In the course of the successive impression-making operations, after the notches have been initially but insufiiciently cut, it is essential that the tumbler-pins, restrained by the shearing stress applied to them, shall be axially movable under the pressure exerted by the inclined faces of the notches that are cut in the edge of the keyblade and rubbed against the tips of the driverpins when the key is reciprocated in the manner described. I have discovered that if such movement of the tumbler-pins be positively prevented, the impression system of opening a lock cannot be successfully practiced. I am aware that mushroom and spool tumbler-pins have been devised, to defeat such opening of locks, but it appears that these structures, While effective to some extent, are not entirely adequate.

In accordance with my invention, I provide in such a multiple keyway look a series of sharpedges barbs or serrations in the bodies of the tumbler-pins. In this case, only the pins (1. are of such specialized form, but it is to be understood that the pins may also be so elaborated, if desired. Advantageously, the barbs or serrations formed in or on the circumferential face of each pin consist in the turns of a sharp-edged square thread 23 that is rolled or cut in the body of the pin, as illustrated in Fig. IX. The thread extends in effect throughout the length of the pin. I have found that tumbler-pins of this construction absolutely safeguard my lock against the impression system, and it is to be understood that such tumbler-pins will prove very effective in any type of tumbler-pin lock.

The great number of lock combinations possible in my structure will be manifest to those skilled in the art. By varying the lengths of the driver-pins b in the six sets of tumbler-pins, thousands of different look combinations may be obtained. The number of radially extending sets of tumbler-pins, the number of pins in each set, the angular spacing between the sets of tumblerpins, and the sizes of the key-receiving bore 8 and stem 9 all may be varied and so provide an untold number of lock combinations.

I claim as my invention:

1. In a lock structure including a barrel, a rotary key-receiving plug secured in said barrel,

tumbler-pins arranged in a plurality of sets of' bores extending radially of the assembled plug and barrel with the several sets spaced angularly from each other, said pins normally extending across the shear-line between plug and barrel and locking said plug against rotation, said tumbler-pins being adapted to yield, to a key-blade of proper form inserted in said plug, into positions radially outward from said shear-line and to release the plug for rotation in the barrel, a rotatable member, a plurality of locking bolts ex tending substantially radially of the assembled structure and pivotally connected to said rotatable member eccentrically of its axis, lostmotion means effective upon rotation of said plug through a relatively great angle for rotating said member through a relatively small angle, to shift said bolts between alternate positions, means for limiting rotation of said member when it has been moved through said relatively small angle; the refinement herein described in which the angular interval between two of said sets of tumbler-pins is less than the sum of said relatively great angle and said relatively small angle.

2. In a lock structure including a barrel, a rotary key-receiving plug secured in said barrel, a plurality of sets of tumbler-pins extending radially of the assembled barrel and plug, with the several sets spaced angularly one set from another, said pins normally extending across' the shear-line between plug and barrel for locking said plug against rotation, said tumbler-pins being adapted to yield to a key of proper form inserted in said plug, into positions radially outward from said shear-line for releasing the plug for rotation in said barrel, a lock-bolt, and means including a rotary lost-motion device connecting said lock-bolt to said rotary plug; the refinement herein described in which the angular interval between two of the said sets of tumbler-pins is less than the lost-motion interval of the said device.

3. In a lock including a barrel, a key-receiving plug rotatable in said barrel, a plurality of tumbler-pins extending radially of the barrel and plug and arranged in sets that extend angularly to one another, and lock-operating means connected through a lost-motion device to said plug and effective upon rotation of the plug from normal position through a relatively great angle to shift said means through a relatively small lock-operating interval; the refinement herein described in which the angle between two of said sets of tumbler-pins is less than said relatively great angle.

4. In a lock including a barrel, a key-receiving plug rotatable in said barrel, a plurality of tumbler-pins extending radially of the barrel and plug and arranged in sets that extend angularly to one another, and lock-operating means connected through a lost-motion device to said plug and elTective upon rotation of the plug from normal position through a relatively great angle to shift said means through a relatively small lockoperating interval; the refinement herein described in which the angle between two of said sets of tumbler-pins is less than the angle through which said plug is rotatable from normal position to take up the lost-motion in said device.

WILSON R. NECKERMAN.

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