System for master keying axial pin tumbler locks

[57] ABSTRACT

A system for master keying axial pin tumbler locks which includes providing at least certain of the combination pins with at least two different axially spaced surfaces facing the keyway for cooperating with differently shaped notches in the end of a key advanced through the keyway. In its preferred form, the master keying combination pins are stepped so as to form a cylindrical head portion of relatively small diameter and a base portion of a larger diameter and the keys include stepped notches that permit engagement with either the head portion or the base portion of said combination pin so as to permit two different keys to operate the same pin. The system described may be adaptable to grandmaster keying, great grandmaster keying, etc., as well as master keying.

Claims, 13 Drawing Figures

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PATE»£D®12I»3

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SSI1 HF 3

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PATENTED JUN 12 W 3,738,136

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PATENTED JUN 121973

3,738436

SHEW 3 OF 3

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3,738

SYSTEM FOR MASTER KEYING AXIAL PIN TUMBLER LOCKS

DESCRIPTION OF THE INVENTION

The present invention relates generally to tubular pin 5 tumbler locks and, more particularly, to the master keying of such locks.

Master keying systems for axial pin tumbler locks have been developed and used heretofore, but such systems have generally required the use of master pins or ¹⁰wafers, in addition to the conventional top and bottom pin tumblers, as well as a special master sleeve (or “washer” or “ring”) for holding the master pins. The master pins are normally positioned between the combination and driver pin, so that when the lock spindle ¹⁵is rotated by its key, the master pins frequently become wedged in a pin well or caught in a wrong position. This traps the key in an intermediate position, making it impossible to either open the lock or to turn the key back _2Qto its starting position for withdrawal. Consequently, such a malfunction renders the lock inoperative, and also may have a harmful effect on the reputation of the lock manufacturer.

It is, therefore, a primary object of the present inven- 25 tion to provide an improved method and apparatus for master keying tubular pin tumbler locks without the use of special master pins and master sleeves.

Another object of the invention is to provide an improved master keying method and apparatus of the 30 foregoing type which minimizes failures and “lockouts” and, therefore, is more dependable and troublefree than master keying techniques used heretofore.

It is a further object of the invention to provide an improved master keying method and apparatus of the ³⁵type described above which provides innumerable possible combinations so that different master keys can be designed for groups of locks as desired, thereby making the master keying system feasible for use in locks which are manufactured commercially in large numbers. Yet ⁴⁰another object of the invention is to provide such an improved master keying system which can also be used to provide grandmaster keying, great grandmaster keying, sub-master keying, etc. ₄₅

A still further object of the invention is to provide such an improved master keying system which is compatible with mass production techniques so that the locks and keys can be efficiently manufactured at high production rates and at a relatively low cost. 50

Other objects and advantages of the invention will become apparent from the following detailed description taken in connection with the accompanying drawings, in which:

FIG. 1 is a perspective view of a tubular pin tumbler 55 lock and service key embodying the invention, with a fragment of the lock removed to show the internal structure;

FIG. 2 is an enlarged section taken along the line 2—2 in FIG. 1 with the key removed from the lock; ⁶⁰

FIG. 3 is the same section shown in FIG. 2 with the change key inserted in the lock, with the position ofthe key when turned 90° shown in broken lines;

FIG. 4 is a plan view of the lock taken along line 4—4 in FIG. 2; ⁶⁵

FIG. 5 is the same section shown in FIG. 2 with a master key inserted in the lock;

,136

FIG. 6 is a perspective view of one of the tumbler pins shown in FIG. 5 and a fragment of a cooperating change key;

FIG. 7 is a perspective view of the tumbler pin shown in FIG. 6 and a fragment of a cooperating master key;

fig. 8 is a linear illustration of a first random selected combination of tumbler pins and a cooperating change key;

FIG. 9 is a linear illustration of the same combination of tumbler pins shown in FIG. 8 and a cooperating master key;

FIG. 10 is a linear illustration of a second random selected combination of tumbler pins and the same master key shown in FIG. 9;

FIG. 11 is a linear illustration of the second combination of tumbler pins and a cooperating master key different from the master key shown in FIG. 9;

FIG. 12 is an enlarged perspective of the key shown in FIG. 1; and

FIG. 13 is a block diagram illustrating a master, grandmaster and great grandmaster keying arrangement in accordance with the invention.

While the invention will be described hereinafter in connection with certain preferred embodiments, it is to be understood that it is not intended to limit the invention to these particular embodiments. To the contrary, the intention is to cover all alternatives, modifications and equivalents within the spirit and scope ofthe invention as defined by the appended claims.

Turning now to the drawings and referring first to FIGS. 1-4, there is shown a tubular pin tumbler lock having a spindle 10 journaled inside a barrel 11. One end 12 of the spindle 10 is threaded for connection to a latch element (not shown) controlled by the lock, while the other end 13 extends through the forward end of the barrel 11 to form an annular key way 14 for receiving a tubular key 15. To lock the spindle 10 to the barrel 11, a plurality of driver pins 16 extend across the interface 17 between an enlarged central portion 18 of the spindle 10 and an annulus 11α pressed into the rear body portion ofthe barrel 11, to prevent rotation of the spindle 10 relative to the barrel 11. More specifically, the driver pins 16 are disposed in circumferentially spaced holes or wells 19 extending axially through the spindle portion 18, and corresponding wells 20 are formed in the annulus 11α. To seal the tumbler pins inside the lock, plugs 21 are threaded into the outer ends of the wells 20, and small coil springs 22 are disposed within the wells 20 between the inner ends of the plugs 21 and the rear ends of the driver pins 16 to bias the pins 16 toward the forward end of the lock.

For the purpose of unlocking the spindle 10 from the barrel 11, a combination pin 30 is disposed in each well 19 and extends forwardly therefrom into an enlarged annular cavity 31 formed by the barrel 11 around the outer periphery of the keyway 14 at the inner end thereof. The biasing force exerted on the driver pins 16 by the springs 22 normally urges the combination pins 30 against the forward end wall of the cavity 31, thereby positioning the driver pins 16 across the interface 17 to lock the spindle 10 to the barrel 11. However, when a key 15 is inserted into the keyway 14, the key depresses both the combination pins 30 and the driver pins 16 until the interface 32 between each cooperating pair of the pins 30 and 16 is aligned with the spindle-barrel interface 17, thereby permitting rotation of the spindle 10 within the barrel 11. To permit opera3,738,136 tion of the lock by only selected keys, the pins 30 and 16 have different lengths, and notches 33 of different axial depths are formed in the end of the key 15 so that for any given combination of pin lengths the lock can be unlocked only by a key or keys having a corresponding combination of notch depths.

In order to provide the required orientation of the key notches 33 relative to the combination pins 30, the key includes a pair of tabs 34 and 35 (FIG. 12) projecting radially from the inner and outer surfaces, respectively, at the forward end of the key. These tabs are adapted to fit into a corresponding pair of grooves 36 and 37 (FIG. 4) formed by the spindle 10 and the barrel 11, respectively, on opposite sides of the keyway 14. To insert the key 15 into the keyway 14, the tabs 34 and 35 must be aligned with the grooves 36 and 37, thereby ensuring proper orientation of the key notches 33 relative to the combination pins 30. To facilitate alignment of the tabs 34 and 35 with the grooves 36 and 37, a pointer 38 aligned with the tabs 34 and 35 is formed on the key handle. When the key is in its fully advanced position in the lock (FIGS. 1 and 3) the outer tab 35 is positioned within the cavity 31 so that it does not interfere with rotation of the key 15 and spindle 10 relative to the barrel 11, while the inner tab 34 engages the spindle 10 to be rotated by the key. To remove the key 15 from the lock, the tab 35 must be re-aligned with the groove 37, thereby ensuring that each combination pin 30 is always aligned with the proper driver pin 16 when there is no key inserted in the lock.

When the key is inserted into the lock, it is stopped at the position where the front end of the key abuts the enlarged central portion 18 of the spindle 10. This stop position of the key, combined with the notches 33 in the key, determines the axial positions at which the retraction of the pins 30 and 16 are stopped when the key is fully inserted into the lock.

In accordance with the present invention, at least certain of the combination pins form at least two different axially spaced surfaces facing the keyway for cooperating with differently shaped notches in the end of a key advanced through the keyway. In order for both of the axially spaced surfaces of any given pin to be accessible to a key in the keyway 14, the surface farther removed from the keyway must extend radially beyond the pin surface located closer to the keyway. Thus, in the illustrative arrangement, each of the combination pins 30 is stepped to form a cylindrical head portion 30α of relatively small diameter, and a base portion 30α of a larger diameter (FIGS. 6 and 7). Thus, the head end 40 and the shoulder 41 of the stepped combination pin 30 form two axially spaced surfaces for cooperating with differently shaped notches in the end of a tubular key 15. More specifically, the end surface 40 can be engaged by the base of any key notch having a width at least as great as the diameter of the pin head 30α, while the shoulder surface 41 can be engaged by any key notch that has an axial dimension greater than that of the pin 30α and that forms a shoulder surface complemental to the pin shoulder 41.

FIGS. 6 and 7 illustrate more clearly how the pin surfaces 40 and 41 cooperate with differently shaped key notches. The key 15 in FIG. 6 forms a notch 33 with a width slightly greater than and an axial depth slightly less than the diameter and axial length, respectively, of the pin head 30α. Thus, when the key is inserted into the lock, it slides over the pin 30 until the base of the notch 33 abuts the end surface 40 of the pin. Further advancement of the key then retracts the pin 30 and the corresponding tumbler pin 16 against the bias of the spring 22 until the leading end of the key abuts the 5 forward end of the spindle portion 18, and at this point the interface of the pins 30 and 16 is aligned with the spindle-barrel interface 17 so that the key 15 can be rotated to turn the spindle 10 within the barrel 11.

The key 15 in FIG. 7 forms a notch 33 having a wide 10 outer portion 33α with a width slightly greater than the diameter of the pin base portion 30£&gt;, and a narrow inner portion 33b slightly wider and larger than the pin head 30α. In the illustrative structure, the inner portion 33b of the key notch has been shown as having an axial 15 length only slightly greater than that of the pin head 30α, but it will be understood that this is only the minimum length of the narrow portion 33b of the notch and that it may have any desired greater length to accomodate pin heads 30α of varying length in different locks. 20 When the key of FIG. 7 is inserted into the lock, it slides over the pin 30 until the shoulder 33c between the wide and narrow portions of the notch 33 abuts the shoulder surface 41 on the pin. Further advancement of the key then depresses the combination pin 30 and 25 the corresponding driver pin 16 against the bias of the spring 22 until the leading end of the key abuts the spindle portion 18, at which point the interface of the pins 30 and 16 is aligned with the spindle-barrel interface 17 so that the key 15 can be rotated to turn the ³⁰ spindle 10 within the barrel 11.

At this point it will be appreciated that the stepped combination pins 30 can be utilized to provide a master keying system by maintaining the axial positions of selected pin surfaces constant throughout any desired ³$ number of locks to be operated by a common master key, while varying the axial positions of the other pin surfaces in the same locks so that a different “change” key is required to operate each lock. For example, the individual change keys may act only on the end sur⁰ faces 40 of the pins, which can be located at a different combination of axial positions in each lock so that a different change key is required for each lock. The master key, on the other hand, may act only on the shoulder surfaces 41, which can be operated by the same master ⁴⁵ key.

To more specifically illustrate how the stepped combination pins 30 can be used to provide a variety of different master keying arrangements, several different ₅θ combinations of pins, and corresponding keys, are illustrated in FIGS. 8-11 with the key in its fully advanced position against the spindle portion 18 in each figure. The axial lengths of the pins 30 and the corresponding key notches are specified in arbitrary units of axial ₅₅ length, with the maximum length of a key notch arbitrarily fixed at seven units. Thus, in FIG. 8 the combination of total notch lengths in the key 15' is 74463 and each of the five notches acts on the end surface 40 of the corresponding pin. That is, the outer end portions ₆₀ of the notches are wide enough to fit over the base portions of the pins so that the head ends of the pins can penetrate through the entire depth of the narrow portions of the notches.

In FIG. 9 the same set of combination pins shown in ₆₅ FIG. 8 is operated by a master key 15 in which the combination of axial lengths of the wide notch portions is 32121, and each of the five notches acts on the shoulder surfaces 41 of the pins. It can be seen that the two

3,738,136 different keys 15' and 15 in FIGS. 8 and 9 retract the five pins to exactly the same axial positions by acting on the two different operative surfaces 40 and 41 of the pins. The key 15 of FIG. 9 can be used as a mater for a large number of locks having pin heads 30α with different combinations of lengths and, therefore, requiring different change keys 15'. For example, the depth of the narrow portion of the left-hand slot in the key IS is four units, so this particular notch will accomodate pins having head lengths of zero to four units. This is also true of the second and fourth notches from the left in the key IS. The narrow portions of the other two notches are three units long, and thus will accomodate pin heads ranging from zero to three units in length. Within these ranges, of course, a variety of different combinations of pin head lengths can be devised.

In FIG. 10 a different set of pins is operated by the same master key 15 shown in FIG. 9. This second set of pins differs from the first set only in the lengths of the pin heads, which are 34233 within the limits of the narrow portions of the key notches. The base of the pins in FIG. 9 have the same combination of lengths as the pins of FIG. 8, namely 32121. Consequently, as far as the key 15 is concerned both sets of pins are the same, since the key “sees” only the shoulder surfaces 41. While the same master key 15 operates both sets of pins shown in FIGS. 1-3, it will be recognized that the two sets of pins require two different change keys. Thus, the change key that operates the pins in FIG. 10 must have a total notch length combination of 66354, as constrasted with the change key 15' combination of 74463.

The keys 15' and 15 illustrated in FIGS. 8-10 are designed to act exclusively on either the end surfaces 40 or the shoulder surfaces 41 of the pins. However, ³⁵the change keys and/or the master key may alternatively be designed to act on the end surfaces 40 of certain pins and the shoulder surfaces 41 of the other pins in the same lock. Thus, in FIG. 11 there is shown a third set of pins operated by a key 15' having wide notch portions of lengths 42121 and a narrow notch portions of lengths 22342. The two end notches and the middle notch act on the shoulder surfaces 41 of the respective pins while the other two notches act on the end surfaces 40. As in the case of key 15, there are a wide variety of different possible pin combinations within the range of the key 15', so it can be used as a master key if desired.

The stepped combination pins 30 can be used not only for master keying but also for grandmaster keying, great grandmaster keying, etc. For example, as illustrated in FIG. 13 locks A and B might be operated by a master key No. 1, locks C and D by a second master key No. 2, locks E and F by a third master key No. 3, and locks G and H by a fourth master key No. 4. A first grandmaster key No. 1 might then operate all the locks A-D served by the two master keys No. 1 and No. 2 while a second grandmaster key No. 2 operates all the locks E-H served by master keys No. 3 and No. 4, and a great grandmaster key might operate all the locks A-H. A grandmaster key for the two different pin arrangements shown in FIGS. 10 and 11, for example, could have a first notch with a wide portion 4 units long and a narrow portion 2 units long, and four other notches with wide portions 2, 1, 2 and 1 units long, respectively, and narrow portions at least 4, 3, 4 and 3 units long, respectively. Such a grandmaster key would operate on the head of the first pin and the shoulders of the other four pins. It will be appreciated that a wide variety of different service key combinations would be available for locks served by such a grandmaster key; that is the lengths of the head portions of four of the five pins, and the corresponding portions of the change key notches, could be varied over the entire range of lengths available beyond the lengths of the wide portions of the key notches.

While the invention has been described with specific reference to the use of cylindrical combination pins which are stepped to provide cross-sections of two or more different diameters along the lengths of the pins, it will be understood that the different axially spaced radial surfaces required by the invention may be provided with different cross-sectional configurations, such as square or triangular for example. Further, different cross-sectional configurations may be provided on a single pin; for example, the pins could be provided with head portions with a square cross-section and base portions with a circular cross-section, or vice versa. Similarly, the cross-sectional configurations of the pins may be varied around the circumference of the lock spindle as well as along the axis thereof, for example, some pins may have circular cross-sections and others square, and still others triangular, within the same lock. Thus, it can be seen that there are innumerable possible combinations that can be formed by varying the configuration and/or the dimensions of the drive pins in the axial and/or circumferential directions.

In the foregoing description and in the drawings there has been shown illustrative axial pin tumbler lock arrangement incorporating my invention wherein only five sets of pin tumblers are present. It will be appreciated by those skilled in the art that the invention may be applied to any number of sets of pin tumblers in the locks whether it is 7 or 8, for example, and furthermore, the locks may include one or more of the present multiple diameter combination pins with conventional single diameter pins.