US2227791A - Safety lock - Google Patents

Description

Jano7, 1941. M S I 2,227,791

SAFETY Lbcx Filed April 1, 1939 2 Sheets-Sheet 2 77 g. as 1' Q 64 85- I: I 5 72 73 74 6 0 :1 F3114 w f 76 I =4 U L 5 J7 l 53:12

' INVENTOR' Jn a/ph flan":

ATTORNEY Patented Jan. 7, 1941 UNITED STATES PATENT OFFICE 13 Claims.

This invention relates to locks, and more particularly refers to improvements in looks of the pin-tumbler type, preventing the surreptitious operation of locks of such type.

When an attempt is made to open a lock with out using a key, that is, by picking the lock, it is necessary to bring the surfaces of abutment between the drivers and their respective tumblers into coincidence with the circumferential surface of the barrel. In locks of the type to which the present invention refers, this operation is called feeling, due to the fact that it is necessary to feel or find the line set by the periphery of the barrel. To this end it is necessary to first effect, such fractional turning movement of the barrel as may be permitted by the slight clearance between the tumblers and their housings in the barrel, and then, by means of a wire or other object, to gradually force upwardly one tumbler after another, feeling the exact position of register each time, when the corresponding driver engages the edge of the opening in the barrel and is prevented from further exerting pressure against the tumbler.

The primary object of the present invention is to provide, in a lock of the pin-tumbler type, novel and improved means for preventing the operation of the look without the use of a proper key.

Another object is to provide, in a pin-tumbler lock, a novel and improved arrangement of looking pins, making it necessary for said pins to be operated in a predetermined sequence in order to release the barrel for unlocking.

A further object is to provide, in a lock of the character mentioned, means for positively preventing the release of at least one of the pins from the locking position unless one or more of the other pins have first been set in a predetermined position with respect thereto.

An additional object is to provide, in a lock of the pin-tumbler type, means to prevent opening of the look by touch or by feel, by providing in the barrel a clearance for some of the pin guides, wide enough to insure a condition whereby a slight turning movement of the barrel permitted by the close fit of the remaining pins will not be sufiicient to interfere with the return movement of the drivers and tumblers registering with the openings having a wider clearance.

Other objects and advantages of the present invention will more fully appear as the description proceeds and will be set forth and claimed in the appended claims.

Several embodiments of my invention are illustrated by way of example in the accompanying drawings, in which:

Fig. l is a longitudinal section of a pin-tumbler lock, embodying one form of my invention;

Fig. 2 is a fragmentary similar sectional view, 5 in an enlarged scale;

Fig. 3 is a longitudinal sectional view of a pintumbler lock, embodying an alternative form of my invention;

Figs. 4 and 5 are respectively a side view and an end view, in an enlarged scale, of the frictional locking element shown in Fig. 3;

Figs. 6 and 7 are respectively a longitudinal section and a side view of a spring and plunger, which may be used in place of the element shown in Figs. 4 and 5;

Fig. 8 is a longitudinal sectional view of a pin-tumbler lock, embodying another alternative form of my invention;

Fig. 9 is a transversal section thereof through line 9-9 of Fig. 8;

Fig. 10 is a plan view of a locking spring plate, used in the lock shown in Figs. 8 and 9, showing the pins in section;

Fig. 11 is a view similar to Fi 8, showing the barrel about to be released for rotation by insertion within it of a proper key;

Fig. 12 is a longitudinal section of a lock, embodying still another form of my invention;

Fig. 13 is a transversal section thereof through line l3-l3 of Fig. 12;

Fig. 14 is a plan view of the shiftable locking plate used in the lock shown in Figs. 12 and 13;

Fig. 15 is a longitudinal section of a lock, showing a modification of the embodiment of my invention illustrated in Figs. 12 to 14; and

Fig. 16 is a transversal section through line l6l6 of Fi 15.

In the preferred embodiments of my invention the operation of one or more of the locking pins is dependent upon the operation of one particular pin, which I shall call the controlling pin. The function of said controlling pin is to control the action of one or more of the other pins so that either the normal operation of said other pin or pins is interfered with by another element interlocking with the controlling pin if the controlling pin is shifted from its normal locking position, or else, said controlling pin will permit the operation of one or more of the other pins only when said controlling pin is in its normal locking position and said interlocking element is in a noninterfering position.

In carrying my invention into practice at least one of the pins, other than the controlling pin, 55

slides through an openingin the barrel, providing an amount of clearance considerably greater than that allowed by the opening provided for the controlling pin, so that any such exceedingly small turning movement of the barrel as may be allowed by the sliding fit provided for the controlling pin will not be sufiicient to bring the edge of the wider opening provided for the other pin or pins to a position where it will prevent the free return of such other pin or pins to their locking position if forced therefrom by a picking implement against the action of their spring.

Insofar as this other pin or pins are concerned, the clearance thus provided destroys the possibility of a person attempting to open the lock without a proper key, by causing the barrel to engage the driver of such pin or pins and prevent their automatic return to the locking position and thus permitting of their being gradually forced upwardly to the position where the intruder may As previously stated, the controlling pin moves through the barrel in a passage providing a close fit, such as is normally provided in an ordinary look. In one embodiment of my invention if the controlling pin is pushed upwardly by means of a picking. implement it automatically causes the element interlocking therewith to exert a pressure against the side of one or more of the other pins and this pressure prevents such other pin or pins from returning to their normal looking position when forced inwardly within their housings, irrespective of the amount by which it or they are displaced. In other words, there is i no predetermined position at which the person attempting to pick the lock may definitely feel that the top of the tumbler or tumblers has reached the right unlocking position.

In another preferred embodiment of my invention, the controlling pin is actually prevented by the element interlocking therewith from moving inwardly unless one or more of the other pins have previously been set in their unlocking position and, as stated, such other pin or pins cannot be set in their unlocking position except by the use of a proper key.

Therefore, it follows that in all preferred forms a lock embodying my invention comprises a number of locking pins, including a, controlling pin, so arranged that in order to set the lock in the unlocking position, the controlling pin should or must be moved from its locking positiononly after the other pin or pins controlled thereb have reached their unlocking position.

A clearer understanding of the invention will be had by referring to Figs. 1 and 2. .In said figures, 2| designates the shell and 2| designates the barrel rotatably mounted within said shell.

The shell is provided with housings 22, 23, 24, 25, within which are mounted the pin drivers 26, 21, 28, 29, and their springs 30. The barrel is made with corresponding openings communicating with the key slot 3| for the accommodation of tumbler pins 32, 33, 34 and 35.

The openings 32', 33', 34' through the barrel, within which the tumbler pins 32, 33, 34 are slidably inserted, have a diameter slightly larger than that of said pins, whereas 'the opening 35' through which pin 35 is inserted provides a close fit therefor. The pin 35 and its driver 29 together form the controlling pin tumbler, said controlling tumbler being preferably the last one in the row.

The driver 29 of the controlling tumbler is formed with a neck 36, which, when the pin 35 is in its locking position as shown, is engaged by a ball 31 inserted within a transversal passage 38 extending between housing 25 and housing 24. The diameter of said ball is such that when it interlocks with neck 33 its outer surface just clears the surface of driver 28 of the adjoining pm.

Said driver 28 is also formed with a neck 39,

'so positioned that said neck 39 will remain in line with passage 38, so as to be engageable by ball 3'! when its corresponding tumbler 34 has moved to the unlocking position, as shown in Fig. 2.

It is obvious that by virtue of this arrangement, when both tumblers 34, 35 are in their locking position, shown in Fig. 1, it is impossible to force tumbler 35 inwardly to its unlocking position unless tumbler 34 is first moved inwardly to its unlocking position, shown in Fig. 2. In said Fig. 2, 40 designates the key which has been almost fully inserted within the key slot, said key being in a position where by further movement towards the right it will force the tumbler 35 to the position 35", shown in dotted lines, corresponding to the unlocking position of said tumbler, the other tumblers occupying their respective unlocking positions.

When said tumbler 35 is moved to the position 35', the neck 36 of the driver 29 will become disengaged from the ball 31 and will exert a cam action upon said ball, forcing it across passage 38 into engagement with the neck 39 of driver 28.

When the key is removed the spring behind driver 29 will return said driver and its tumbler 35 to the locking position and after such position has been reached, the spring behind driver 28 and its tumbler 34 will be free to return said driver and tumbler to their own locking position, in so doing forcing the ball 31 back to the position shown in Fig. 1. It is thus seen that any attempt to gradually forcetumblers 32, 33 and 34 inwardly by means of a picking implement will be unsuccessful. because their respective drivers and springs will immediately return such tumblers to their locking position. It is also seen that the tumbler 35 of the controlling pin cannot possibly be forced inwardly because it is held in position by ball 31, unless the tumbler 34 is first forced to its unlocking position and, as stated, the properunlocking position of tumbler 34 cannot possibly be'located in the usual manner because in all positions said tumbler will be responsive to the action of the spring behind its driver 28.

It is thusseen that a lock constructed in accordance with my invention cannot possibly be picked by the usual methods and that its proper key must be used for its operation.

In Fig. 3 I illustratean alternative form of my invention inwhich the controlling pin can be forced inwardly by means of a suitable picking implement but will, in its turn, immediately cause a frictional action to take place against the side of one or more of the other pins, temporarily destroying their capacity to respond to the action of the spring behind theirrespective drivers.

Referring to said Fig. 3, 4i designates the shell and 42 the barrel, said shell being provided with housings 43, 44, 45, 43 for drivers 41, 48, 49, 50, and their respective springs El, 52, 53,54. The

barrel is provided with passages for the tumblers 55, 56, 51, 58, the passages, 56', 57 for tumblers 55, 56, 51 being, as in the previous case, a trifle larger in diameter than said tumblers, whereas the passage 58 for tumbler 58, provides a normally close fit. As an added precaution the clearance provided for tumbler 51 is preferably made a little smaller than that, for tumblers 55, 56, because since it is impossible to feel the correct unlocking position of tumbler 51, it will not be possible to turn the barrel to a position permitting of picking tumblers 55, 56, unless by mere chance tumbler 51 should have been set first in its unlocking position.

Tumbler 58 and its driver 50 together orm the controlling pin. Said tumbler 58 is formed with a neck 59, which is normally engaged by a spring element Gil, inserted in a transver-sal passage 5!, extending between passages 58 and 57, when said tumbler 58 is in its locking position shown.

When said tumbler 58 is so engaged by spring element 60, said spring element is fully extended and it does not exert any pressure against tumbler 57 so that it does not interfere With the free return of said tumbler to its locking position when forced therefrom. However, when tumbler 58 is forced inwardly from its locking position it will gradually compress spring element 6i], forcing it against the surface of adjoining tumbler 51, so that said tumbler 5'! will automatically lose its sensitivity or responsiveness to the action of spring 53 back of its driver 49.

The spring element may be made in one piece, as shown in Figs. 3, 4 and 5, or else it may consist of a spring 62 and a plunger 63, having a head 64, as shown in Figs. 6 and 7.

The frictional action, due to the displacement of the controlling pin, may also be exerted simultaneously upon all of the remaining pins by means of an arrangement, such as shown in Figs. 8 to 11. ment is constituted by a plate 65, slidable within a longitudinal slot 66, provided in the barrel 61, said plate having a beveled end edge 68 normally engaging an annular groove 69, in the tumbler 19 of the controlling pin and being cut off to form an opening H, clearing the remaining tumblers l2, 13, It.

The opening T! in said plate is cut with an irregular profile, forming spring shoes l2, 13, M, normally registering with the surface of tumblers l2, 73, M, respectively, without exerting any pressure thereagainst when tumbler NJ is in its locking position. When said tumbler It! is moved inwardly from its locking position, it will force inwardly plate 65 and thus cause spring shoes l2, 13', M to exert a pressure against the side surface of the corresponding tumblers, causing said tumblers to lose their responsiveness to the action of their respective springs, explained in connection with the arrangement of Fig. 3. It will be understood that the parts will be so proportioned that the tumblers cannot be pushed above plate 65, otherwise picking of the lock would be greatly facilitated.

Fig. 11 shows the lock about to be set in the unlocking position by key 15, said key having been inserted through the key slot is a distance suiiicient to set tumblers l2, 13, M in their unlocking position and being about to set tumbler ll) of the controlling pin to the unlocking position, forcing the plate 65 in its friction exerting direction.

Due to the resistance offered by the friction exerting element 6%} in the case of Fig. 3 and by In the same the friction exerting elefriction. exerting element 65 in the case of Figs. 8 to 115,. itis necessary to make the spring 54 in the one case and the spring H in the other, back of the controlling pins, sufiiciently strong to overcome the friction exerted by the, friction exerting element, against the tumbler of the controlling pin when said tumbler is moved away from its, locking position. r

The sliding plate principle can also be applied for a positive locking of all the pins by the'controlling pin in place of the ball arrangement shown in. Figs. 1 and 2.

For instance, in Figs. 12 to 14, the driver it of the controlling. pin is formed with an annular groove 19 having an upwardly tapering surface, and the slidable plate 89 inserted within a longitudinal slot 8 l provided in the shell 82, is formed with an, opening 83 having a similarly slanted side surface.

Plate 80 is also provided with two openings 86, 85, having an upwardly slanting surface, said openings 84', 85' registering with drivers 86, 81, respectively, when the edge of opening 83 engages the annular groove 19 in driver 18.

Drivers 86 81 are also formed with annular grooves 88, 89, respectively, said grooves having a downwardly tapering surface and being positioned so that they will be on the same plane with plate 8!! when said drivers are moved to their unlockingposition.

The arrangement is such that when all the tumblers are in their locking position, as shown, the plate 80 cannot be shifted with respect to the drivers because the smaller diameter of its openings I34, 85 register with the periphery of drivers 85, 81. In this position, as stated, the edge of opening 83 engages the shoulder formed by groove 19 in driver 18 and prevents said driver from being moved inwardly within its housing.

Such inward movement of driver 18 will only be come possible after drivers 86, 81 will have been moved to their unlocking position when the plate 80 can be shifted to cause the edges of its openings 84, 85 to engage grooves 88, 89, respectively.

The slanting of opening 83 and of the bottom surface of groove 19 is such as to cause the surface of said groove to exert a cam action against the plate 80, forcing the plate inwardly when driver 18 is inwardly displaced.

In the same manner, the slanting of the surface of openings 84, 85 and grooves 88, 89 in the opposite direction is such as to cause drivers 86, 81to shift the plate towards driver 18 when drivers 86, 81 are returned to their locking position by their springs.

This arrangement, therefore, makes it necessary for the key to actuate the tumbler of the controlling pin only after the other pins have been set in the unlocking position, and when the key is withdrawn the spring back of the driver 18 will first return said driver to the locking position before the other drivers can be similarly acted upon by their respective springs.

A locking plate similar to plate 80 used in the arrangement just described, may be returned to its normal position where it engages the controlling pin by the action of springs pressing against one end of said plate. In such case, the plate can be forced away from its locking position by the controlling pin by providing the plate and pin with cooperating cam acting slanting surfaces in the manner previously described, but since the return of the plate to its locking position will be eiiected by additional springs it is not necessary to provide slanting engaging surfaces between the plate and the remaining pins. An arrangement of this type is shown in Figs. and 16, where the driver 99 of the controlling pin is formed as in the previous case with an annular groove 9|, having an upwardly tapering surface, said groove being engaged by the edge of an opening 92 is plate 93, having a correspondingly slanted surface. Said plate 93 is also provided with two openings 94, 95, registering with the drivers 96, 97, respectively, said drivers being provided with straightsided annular grooves 98, 99, registering with said plate and adapted to be engaged thereby when said drivers 96, 91 are moved to their unlocking position.

It will be understood that the action of driver 90 upon the plate 93 when said driver is moved inwardly within its housing from its locking position is exerted against the action of two springs,

such as l 99, inserted in two sockets I 0|, I02, bearing against the inner end of plate 93. Due to the action of said springs, plate 93 will be automatically returned to the position shown where it engages driver 90 as soon as said driver is returned to its locking position by its respective spring. 25

It is thus seen that in every case it is necessary to force the tumbler of the controlling pin to its unlocking position before the barrel can be turned and that either said tumbler cannot be moved to its unlocking position until one or more rangement by the addition of an element interlocking with the controlling pin. In this case all the pins can be actuated in any sequence by the use of the proper key but the lock could only be picked by pushing up the pins in a predetermined sequence according to the relative clearances provided for the various pins.

"-sponding recesses of the barrel.

It will be understood that the locking action is due entirely to the drivers projecting partly in the recesses of the housing and partly in the corre- The rotary movement of the barrel permitted by any one pin when in the locking position is, therefore, equal to the sum of the clearance between the driver of said pin and the recess in the barrel and between said driver and the corresponding recess in the housing. One of the features of the invention is that due to the close fit provided for the controlling pin, the rotatory movement of the barrel allowed by the controlling pin is not sufiicient to interfere with the free action of the other pins.

However, inasmuch as the free action of the drivers of the other pins also depends on whether the rotary movement of the barrel is such as not to cause the edge of the recess in the barrel to pass beyond the edge of the corresponding recess in the housing, forming a ledge in the path of the driver against which the driver may come to rest, another condition essential to the proper working of the invention is that for any one pin the re- .cess in the barrel should have a diameter slightly larger than that in the housing, the recess in the housing providing a normal sliding fit for the driver, and preferably also for the tumbler, both the tumbler and the driver being preferably of the same diameter.

The arrangements described, therefore, render a lock practically impossible to operate without a proper key. The inventive idea may be applied in ways different from those shown by varying some of the constructional details; the drawings, therefore, should be understood as being intended for illustrative purposes only and not in a limiting sense.

I, accordingly, reserve the right to carry my invention into practice in all those ways and manners which may enter, fairly, into the scope of the appended claims.

I claim:

1. In a pin-tumbler lock comprising a housing having a plurality of parallel recesses, a barrel having parallel recesses adapted to align with the recesses in said housing, divided locking pins slidable within said recesses from a locking to an unlocking position, and springs urging said pins to their locking position, an element interposed between two of said pins, said element being adapted to laterally interlock with one of said pins when said pin is in a predetermined position, said element being caused by one of said pins to interfere with the normal operation of the other, except when one of said two pins occupies a given position, the recesses for the interlocking pin in said barrel and housing providing a close sliding fit for said pin, and the recess in said barrel for the other pin having a diameter leaving a greater clearance around said pin, said diameterbeing also greater than that of the corresponding recess in the housing.

2. In a pin-tumbler lock comprising a housing having a plurality of parallel recesses, a barrel having parallel recesses adapted to align with the recesses in said housing, divided locking pins slidable within said recesses from a locking to an unlocking position, and springs urging said pins to their locking position, an element interposed between two of said pins, said element being laterally shiftable with respect to the said two pins from a position Where it interlocks with one of said pins when said pin is in its locking position, to a position where it interlocks with the other pin when the latter pin is in its unlocking position, the recesses for the interlocking pin in said barrel and housing providing a close sliding fit for said pin, and the recess in said barrel for the latter pin having a diameter leaving a greater clearance around said pin, said diameter being also greater than that of the corresponding recess in the housing.

3. In a pin-tumbler lock comprising a housing having a plurality of parallel recesses, a barrel having parallel recesses adapted to align with the recesses in said housing, divided locking pins slidable within said recesses from a looking to an unlocking position, and springs urging said pin to their locking position, an element adapted to interlock with one of said pins when said pin occupies its locking position, said element allowing the free movement of at least one of the other pins from its looking to its unlocking position only when said element is in interlocking relation with the first mentioned pin, the recesses for said first mentioned pin in said barrel and housing providing a close sliding fit for said pin, and the recess in said barrel for said other pin having a diameter leaving a greater clearance around said other pin, said diameter being also greater than that of the corresponding recess in the housing.

4. 'In a pin-tumbler lock comprising a housing having a plurality of parallel recess-es, a barrel having parallel recesses adapted to align with the recesses in said housing, divided locking pins slidable within said recesses from a looking to an unlocking position, and springs urging said pins to their locking position, an element interposed between two of said pins, said element being latterly shiftable with respect to the said two pins from a position where it interlocks with one of said pins when said pin is in its locking position, to a position where it interlocks with the other pin when the latter pin is in its unlocking positon, said element abutting against said latter pinwhen said pin is in its locking position, and preventing movement of the former pin to its unlocking position until said latter pin has reached its own unlocking position, the recesses for the former pin in said barrel and housing providing a close sliding fit for said pin, and the recess in said barrel for the latter pin having a diameter leaving a greater clearance around said pin, said diameter being also greater than that of the corresponding recess in the housing.

5. In a pin-tumbler lock comprising a housing having a plurality of parallel recesses, a barrel having parallel recesses adapted to align with the recesses in said housing, divided locking pins slidable within said recesses from a locking to an unlocking position, and springs urging said pins to their locking position, a laterally yielding element interlocking with one of said pins when said pin occupies its locking positon, said element being urged by said pin to press against at least one of the other pins, exerting a frictional resistance to the latter pins movement, when the first mentioned pin is displaced from its locking position.

6. In a pin-tumbler lock comprising a housing having a plurality of parallel recesses, a barrel having parallel recesses adapted to align with the recesses in said housing, divided locking pins slidable within said recesses from a locking to an unlocking position, and springs urging said pins to their locking position, a laterally yielding element interlocking with one of said pins when said pin occupies its locking position, said element being urged by said pin to press against at least one of the other pins, exerting a frictional resistance to the latter pins movement, when the first mentioned pin is displaced from its locking position, the recesses for said first mentioned pin in said barrel and housing providing a close sliding fit for said pin, and the recess in said barrel for said other pin having a diameter leaving a greater clearance around said other pin, said diameter being also greater than that of the corresponding recess in the housing.

7. In a pin-tumbler lock comprising a housing having a plurality of parallel recesses, divided locking pins slidable within said recesses, and springs urging said pins outwardly from said recesses, a barrel having recesses adapted to align with the recesses in said housing, one of the recesses in said barrel and the corresponding recess in said housing providing a close sliding fit for one of said pins, and at least one of the other recesses in said barrel having a diameter leaving a greater clearance around the pin passing therethrcugh, said diameter being also greater than that of the corresponding recess in the housing and means abutting against the latter pin laterally interlocking with the former pin, when both pins occupy their locking position.

8. In a pin-tumbler lock comprising a housing having a plurality of parallel recesses, divided locking pins slidable within said'recesses, and springs urging said pins outwardly from said recesses, a barrel having recesses adapted to align withthe recesses in said housing, one of the re- .cessesin said barrel and the corresponding recess in said housing providing a close sliding fit for one of said pins, and at least one of the other recesses in said barrel having a diameter leaving a greater clearance around the pin passing therethrou'gh, said diameter being also greater than that of the'corresponding recess in the housing, and means abutting against the latter pin laterally interlocking with the former pin, when both pins occupy their locking position, said means being adapted to laterally interlock with the latter pin when said pin is moved to its unlocking position, and being urged towards said latter pin by the former pin, when said former pin is displaced from its locking position.

9. A pin tumbler lock comprising a housing having a plurality of parallel recesses, a barrel having parallel recesses adapted to align with the recesses in said housing, divided locking pins slidable within said recesses from a looking to an unlocking position, and springs urging said pins to their locking position, the recess provided in said barrel and the corresponding recess in said housing for at least one of said pins providing a close sliding fit for said pin and one at least of the recesses provided in the barrel for the other pins having a diameter leaving a greater clearance around said pin, said diameter being also greater than that of the corresponding recess in the housing.

10. A pin tumbler lock comprising a housing having a plurality of parallel recesses, a barrel having parallel recesses adapted to align with the recesses in said housing, divided locking pins slidable within said recesses from a looking to an unlocking position, and springs urging said pins to their locking position, the recess provided in said barrel and the corresponding recess in said housing for one of said pins providing a close sliding fit for said pin, and the recesses provided for the other pins having each a diameter leavinga different clearance around the corresponding pin, greater than the clearance of the sliding fit provided for the first mentioned pin, each of the latter recesses also having a diameter greater than that or the corresponding recesses in the housing.

11. A pin tumbler lock comprising a housing having a plurality of parallel recesses, a barrel having parallel recesses adapted to align with the recesses in said housing, divided locking pins each comprising a. driver slidable within said recesses from a looking to an unlocking position, the fractional turning movement of the barrel permitted by one of said drivers when in its locking position being less than that permitted by at least one of the other drivers, the recess in the barrel for the latter driver or drivers having a diameter greater than that of the corresponding recess in the housing.

12. A pin-tumbler lock comprising a housing having a plurality of recesses, a barrel having recesses adapted to align with the recesses in said housing, divided locking pins slidable within said recesses from a locking to an unlocking position, and springs urging said pins to their locking position, an element interposed between two of said pins, said element being adapted to laterally interlock with one of said pins when said pin is in a predetermined position, said element being caused by one of said pins to interfere with the normal operation of the other, except when one of said two pins occupies a given position, the recesses for the interlocking pin in said barrel and housing providing a close sliding fit for said pin, and the recess in said barrel for the other pin having a diameter leaving a greater clearance around said pin, said diameter being also greater than that of the corresponding recess in the housing.

13. A pin-tumbler lock comprising a housing having a plurality of recesses, a barrel having recesses adapted to align with the recesses in said housing, divided locking pins slidable within said recesses from a locking to an unlocking position, and springs urging said pins to their locking position, an element interposed between two of said pins, said element being adapted to laterally interlock with one of said pins when said pin is in a predetermined position, said element being caused by one of said pins to interfere with the normal operation of the other, except when one of said two pins occupies a given position, the recesses for the interlocking pin in said barrel and housing providing a close sliding fit for said pin, and the outer end at least of the recess in said barrel for the other pin having a diameter leaving a greater clearance around said pin, said diameter being also greater than that of the corresponding recess in the housing.

ADOLPH MOSES.

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