Untitled record

March 24, 1964

3,125,878

L. GUTMAN

CONSTRUCTION KEY DEVICE

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ATTORNEY

March 24, 1964

3,125,878

L. GUTMAN

CONSTRUCTION KEY DEVICE

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125 878

United States Patent Office Patented Mar. 24, 1964

3,1'25,878

CONSTRUCTION KEY DEVICE

Louis Gutman, Fitchburg, Mass., assignor to Independent Lock Company, Fitchburg, Mass., a corporation of Massachusetts

Filed Feb. 13, 1961, Ser. No. 88,707

Claims. (Cl. 70—383)

This invention relates to an improved lock assembly and more particularly to a pin tumbler lock assembly.

Still more particularly, this invention relates to a lock assembly having a factory-set pin tumbler combination which renders the lock operable by a first key, said lock including novel means whereby operation of the same by a second key will disable subsequent operation by the first mentioned key.

Still more particularly, this invention relates to a pin tumbler device as described whereby subsequent operation by said second or change key will reactivate the tumbler device to a combination which is operable by the first-mentioned key.

Still more particularly, this invention relates to a pin tumbler assembly particularly adaptable for use with a cylinder or residential type lock set.

In the construction of new homes, apartment houses, office buildings and the like, it is desirable to provide the workers or one user with means for locking the partly constructed units in order to safeguard tools or the like which are left on the job and forestall vandalism. After the construction work has been completed, however, it is necessary, in order to assure security to the tenant or owner, to change the combination of the locks previously employed so that the holders of keys during the construction period are not able to re-enter the premises through the use of keys provided to them during the construction period.

In the past, changing of the pin tumbler combination has required removal of the lock from the door, disassembly of the tumbler mechanism and substitution of new driver and follower pins for the original pins—in short, an operation requiring the skills of an experienced locksmith. This application has for an object the provision of a pin tumbler mechanism for use in door locks and the like, the combination of which mechanism may be changed without disassembly of the door lock mechanism or pin tumbler unit.

A further object of this invention is to provide a pin tumbler assembly, the combination of which assembly may be changed through the use of a specially prepared key. A further object of this invention is to- provide a pin tumbler assembly particularly adaptable for use in connection with residential lock sets or the like wherein latch bolt withdrawal is effected by a relatively small angular rotation of the pin tumbler plug, the device of the present invention being adapted to enable combination change through the use of a special key within the limited range of rotation provided in residential type lock units.

Still a further object of this invention is to provide a pin tumbler mechanism having temporary or construction keys and a combination change key, which last named key may be used alternatively to shift the combination to disable operation by the construction key, or restore the assembly so that the construction key may again be utilized.

A further object of this invention resides in the provision of a pin tumbler assembly having one or more pin tumbler elements interposed between the usual driver and follower pins, said auxiliary elements being alternatively removable from or returnable to the interposed position to effect change of the pin tumbler combination by a special combination change key.

Still a further object of this invention is to provide a pin tumbler mechanism, the combination of which may be changed through the use of a special key with but a limited rotation of the key plug with respect to the tumbler casing.

To attain these objects and such further objects as may appear herein or be hereinafter pointed out, reference is made to the accompanying drawings forming a part hereof, in which—

FIGURE 1 is a vertical section through the outside knob of a residential or cylindrical type door lock showing the manner in which the novel pin tumbler assembly is supported in such knob;

FIGURE 2 is a section taken on the lines 2—2 of FIGURE 1;

FIGURE 3 is a magnified vertical section through the pin tumbler mechanism, showing the position of the parts when a temporary or construction key is inserted in the keyway thereof;

FIGURE 3a is a section similar to that of FIGURE 3 with a final or occupant’s key inserted in the keyway;

FIGURE 4 is a section similar to FIGURES 3a and 3 with the combination change key inserted in the keyway;

FIGURE 5 is a vertical section taken on the line 5—5 of FIGURE 4;

FIGURE 6 is a section similar to FIGURE 5, showing the position of the tumbler parts at an intermediate stage during the combination change;

FIGURE 7 is a section taken on the lines 7—7 of FIGURE 6;

FIGURE 8 is a vertical section taken on the line 9—9 of FIGURE 3a.

FIGURE 9 is a section similar to FIGURE 5, showing the position of the tumbler parts after the combination change.

Making reference to the drawings, in FIGURE 1 there is shown a tumbler assembly in accordance with my invention as mounted in the outside knob 10 of a residential lock set. The knob 10, which is specifically described and illustrated in United States Patent No. 2,693,692, includes an outer shell portion 11, a retainer flange 12 and a knob bottom segment 13. A plug assembly 15 is mounted in the knob 10 in a manner to project the outer end 16 of the tumbler assembly through the aperture 17 formed in outer knob segment 11. The flange 12 is slotted at 14, the upper casing portion 16 of the plug assembly 15 being projected through the slotted portion 14 in the assembled condition of the knob to maintain the assembly 15 non-rotatably mounted within the knob 1®. The inner and outer knob sections 13 and 11, respectively, are held together by a spring washer or other means, not shown.

An inner plate 18, provided with a driver slot 19, links the tumbler mechanism with the latch bolt mechanism of the lock L and, in known manner, provides a driving connection to permit latch bolt retraction upon rotation of the plug by a key.

The knob construction and driving connection heretofore described -are known to the art and it will be readily recognized that other forms of knob supports and driving linkages may be substituted therefor in known manner, the invention herein residing in the construction of -the pin tombler mechanism 15. However, its utility resides in the combination with a -pin tumbler plug -which rotates axially -for a small angle to shift the latch bolt mechanism.

In accordance with -the invention, the tumbler mechanism 15 comprises a casing 20, having a longitudinally extending main bore 21. A plug member 2'2, having a generally cylindrical body portion 23, is rotatably mounted within the casing 29. An annular flange 24 on the front or outer face of the plug 22 bears against shoulder 25 of the casing, preventing inward movement of the plug into the casing.

Removal of -the plug in an outboard direction from the casing 2® is prevented by the driving element 18 which is secured to -the inner end of the plug, as by bolt 25, either end of which is secured within a complementally threaded aperture, not shown, formed in the plug 22.

The plug assembly as thus far described is conventional and many known forms of tumbler casing and plug assemblies may be employed without departing from the spirit of the invention.

The plug 22 is formed in the usual manner with a longitudinally extending keyway slot 3®. The casing 20 is provided with a series of parallel cross-bores 31 extending normal to the axis of the plug 22 and opening onto the bore 21. The plug 22 is likewise provided with a series of parallel bores 32 in registry with and coaxial to the cross-bores 31 in the casing 20.

Cross-bores 31 are charged with driver pins 33, driver springs 35 being charged in the bores 31 behind the driver pins 33, thereby serving to urge the same radially inwardly toward the axis of rotation of the plug 22.

Cross-bores 32 of the plug 22 are charged with follower pins 34 and, in the usual manner, are, in the absence of a key, projected into the keyway by the driver pins 33, said driver pins being projected across the bore or shear line a—a, thus preventing rotation of the plug 22.

In the novel pin tumbler assembly herein described, at least one auxiliary pin is introduced between a driver and a follower pin of a cross-bore portion. In the illustrated embodiment, auxiliary pin 36 is introduced between driver pin 33α and follower 34α which reciprocate in the crossbore portions 31α of the casing and 32α of the plug. While the pin 36 is shown in the first cross-bore position, it will be understood that said pin may be placed in any of the cross-bores and that more than one such pin may be employed.

As shown in FIGURES 5, 6, 7 and 8, a passage 4® is formed through the casing 2®, which passage opens onto the bore 21 and is positioned to register with the crossbore 3·2α of the plug 22 in a partially rotated position of said plug. See FIGURES 6 and 7.

In addition, a finger 41 is positioned within the passage 4®, said finger being spring biased radially toward the axis of rotation of the plug 22 by a parti-annular spring band 43, or a like expedient.

In FIGURE 3, the tumbler assembly is shown in conjunction with a temporary or construction key KI, the bitted edge Bl of which is formed with follower pin seats of a height effective to lift the contiguous junctions of the driver and the follower pins 33, 34, respectively, to the shear or parting line a—a or bore 21 of the casing. The bitting Bl likewise lifts the junction between the inner end of driver pin 33α and the outer end of auxiliary pin 36 to said shear line, and it will thus be recognized that the plug 22 may be turned within the casing 28 by rotation of the key KI, causing the driver slot 19 to withdraw the latch bolt.

After construction is completed, it is important to change the lock combination to render key KI ineffective to operate the lock, so that holders of such temporary keys or copies thereof will no longer be able to gain access to the locked premises by the use of such first provided keys. The combination change is effected in my device by shifting the auxiliary pin 36 radially outwardly into the passage 40, after which shift key KI will no longer operate the lock mechanism since, in the inserted position of the key KI, driver pin 33α will be shifted to the position formerly occupied by auxiliary pin 36 and will therefore span the shear line a—a, preventing rotation of the plug. The axial movement of auxiliary pin 36 is effected by a special key K2, to· be hereafter described.

The change key K2 is formed with a bitted edge B2 which, like the key KI, raises the junctions of the driver and the follower pins 33, 34, respectively, to the shear line

87’8 a—a and raises the junction of driver pin 33α and auxiliary pin 36 to said shear line. Unlike key KI, however, which is provided with generally trough-shaped pin seat portions Pl, the pin seats P2, with the exception of the outermost pin seat P'2- are generally flat and somewhat extended in length in the direction of the keyway.

The seat P'2 includes a steep cam portion 45, -which, in the inserted position of the key K2, lies forwardly or inwardly of the follower pin 32α and closely adjacent the innermost end of the latter.

To effect a combination change, key K2 is fully inserted into the plug 22 and the plug rotated from the position through a small angle such as for withdrawing the latch bolt as shown in FIGURE 5 to the position of FIGURE 6, whereat the cross-bore 3·2α of the plug 22 registers with passage 46. With the plug rotated as explained, the key K2 is withdrawn partly outwardly from the key way. Such partial withdrawal or longitudinal movement of the key K2 is made possible by -the flat configuration of the pin seats P2. Such withdrawal will, however, force the cam surface 45 against the follower pin 34α, causing the latter to shift radially and thrusting auxiliary pin 36 outwardly into the passage 4® against the biasing influence provided by spring 43 where this is utilized. See FIGURE 6.

After the auxiliary pin 36 has been deposited -in passage 4®, the plug may be rotated to the normal or aligned position of the cross-bores 31 and 32 and the key K2 withdrawn from -the plug. The auxiliary pins 36 will thereafter ride against the outer periphery or cylindrical portion of the body 23 of the plug 22.

With the combination change thus effected, the lock may be operated by -the final or occupant’s key K3, having a fitted edge portion B3 similar in -all respects to the bitted portion Bl of key KI except that pin seat P'3 of key K3 is sufficiently higher than pin seat P'l of key KI to raise the follower pin 34α an additional distance equal to the height of the removed auxiliary pin 36. Thus the key K3 will raise the outer end of the follower pin 34α to the shear line a—a and will thus be effective to rotate the plug mechanism.

If it is desired to restore the combination to one which will satisfactorily accept the temporary or construction key KI, such change may be effected through the use of the change key K2. To restore the original key combination, key K2 is inserted and then partially withdrawn so that the cam portion 45 adjacent the pin seat P'2 will raise the outer end of follower pin 34α to the shear line a—a. The plug 22 may then be rotated until the bore 32α in the plug 22 registers with the passage 4® in the casing 2®. Key K2 is then forced axially inwardly so that the pin seat P'2 lies beneath the inner end of follower pin 34α. The spring band 43, acting through finger 41, will then be effective to force the auxiliary pin 35 radially into bore 32α and the initial combination will be restored, upon removal of the key K2.

While it is possible to dispense with spring 43 and finger 41, and to induce the auxiliary pin 36 to return to bore 32α under the influence of gravity, the use of such spring and finger arrangement has been found preferable by me.

From the preceding description it will be obvious that both keys KI and K3 will be effective to operate the lock assembly before combination change, and after such change only key K3 may be used for this purpose. It will be further recognized that the pin tumbler mechanism described and claimed herein has particular advantages in connection with a cylindrical lock assembly wherein the latch bolt is withdrawn by partial rotation of the plug unit. Thus, in contrast to a device wherein a plug rotation in the neighborhood of 180° is required to effect a combination change, such change may be effected in the present device at any desired plug rotation by varying the angular offset of the passage 4® from the vertical or cross-bore axes. Thus, cylindrical lock mech :,125,878 anism where plug rotation in excess of 45°, for instance, is prevented by the driving linkage between the plug assembly and the latch bolt retractor mechanism, the passage 40 should be positioned within the limiting range of plug movement provided.

It will be further recognized that an advantage of the herein disclosed device lies in the fact that a conscious operation different from normal key operation of the plug is required to effect a combination change. Thus, it is impossible inadvertently to change the combination through a premature use of the change key K2 since, if such key is used in the normal manner, the lock will be opened but the auxiliary tumbler 36 will not be displaced. It is only when the change key is used and shifted longitudinally in the course of use with the auxiliary tumbler 36 aligned with the passage 40 that a combination change will result.