US3479848A - Side bar lock - Google Patents

Description

Nev. 25, 1969 A. H. GOLDEN 3,479,848

SIDE BAR LOCK Filed July 21, 1967 INVENTOR. A. H. 60L DEN A'i'TORNEYS nited States Patent Filed July 21, 1967, Ser. No. 655,168 Int. Cl. Eb 29/04, 63/00 US. Cl. 70-364 8 Claims ABSCT OF THE DISCLOSURE A lock key plug is equipped with a stack of disc tumblers, some of which lock through engagement with a groove in the bore of an outer cylinder, and others of which control a side bar engaging a further groove in the cylinder bore. The tumblers that engage a groove are arranged with clearance that prevents a transfer of pressures between those tumblers and the side bar. A standard type of key will set all of the tumblers in release position, the tumblers moving in opposition to spring pressure while permitting the side bar to move by spring pressure to release position. The arrangement resists picking while at the same time permitting numerous tumbler combinations with no interchange of keys.

I shall first indicate that it is customary, in the manufacture of locks, to use a series of tumblers which are set by a key to a particular position. By varying the sizes or proportions of the tumblers, or by varying the positions to which they may be moved, the tumblers become operable by keys that are bitted or otherwise formed for particular coaction with the tumblers. Thus, a key that is particularly bitted will set a particular series of tumblers in a release position.

As will be appreciated by those skilled in the art, it is important that locks be so constructed that a particular lock may be operated only by a key intended for that lock, and not by a key that has been bitted for cooperation with the tumblers of another look. Where a key not intended for setting a particular series of tumblers can be used to set those tumblers in release position, we have what the art calls interchange. Many locks have been designed to prevent interchange, but those locks do not oifer the best security because their tumblers may yield to relatively simple picking procedures.

What I seek to accomplish by my invention and actually do accomplish, is the elimination of interchange while yet contributing pick resistance.

In the concept of my invention, I equip a key plug with a series of tumblers that will lock the key plug through engagement with its outer cylinder while controlling a locking member, such as a side bar, that also engages the cylinder. Thereby the tumblers have a locking action that is indirect and also direct. The series of tumblers will be pressed by spring means into locking engagement with the cylinder, being set in release position by a key. The locking member, on the other hand, will be spring pressed to release position. The locking member will move to locking position when the tumblers move to locking position, but that movement of the memher will be against its spring pressure. In other words, there is locking by spring presure, and further locking opposed by spring pressure.

Thus, as an important feature of my invention, I construct a lock with a series of tumblers that will efifect locking through one manner of operation and at the same time in an opposed manner. To pick the tumblers would require the use of different procedures concurrently. Those procedures will conflict with one another, tremendously increasing the difiiculty of picking the tumblers.

As a further feature, I utilize a type of tumbler that acts at the periphery of the key plug to engage an outer cylinder, and that is particularly effective to prevent key interchange. The type of tumbler may normally be vulnerable to picking procedures, but I can very successfully use that type due to the extreme pick resistance of my lock.

As another feature of my invention, I construct my lock with a series of tumblers that will operate in various ways while controlled by a single bitted portion of a key.

I have thus outlined rather broadly the more important features of my invention in order that the detailed description thereof that follows may be better understood, and in order that my contribution to the art may be better appreciated. There are, of course, additional features of my invention that will be described hereinafter and which will form the subject of the claims appended hereto. Those skilled in the art will appreciate that the conception on which my disclosure is based may readily be utilized as a basis for the designing of other structures for carrying out the several purposes of my invention.

Referring now to the drawings:

FIG. 1 shows a perspective view of a lock key plug and tumbler assembly utilizing my invention.

FIG. 2 shows a longitudinal section on the line 22 in FIG. 5, showing the assembled key plug and cylinder, with a key setting the tumblers.

FIG. 3 is cross section showing the tumblers in locking position.

FIG. 4 shows one of the tumblers.

5 is like FIG. 3 but shows the lock in release position.

For the purpose of describing my invention, I have chosen to show in FIG. 1 a key plug 10 of a rather usual kind having a front portion 11 that is formed with a keyway 12, and a rearward end portion 13 having a cam 14 for operating a lock mechanism, not shown. The key plug 10 has a vertical opening 15 formed through it, and a series of disc tumblers 16 are assembled in stacked relation in the opening 15, along with a hairpin type spring 17 at one side of the tumblers. A pair of end plates 18, only one of which is visible in FIG. 1, is utilized simply for purposes of assembling the tumblers 16 and spring 17 in the key plug opening 15. The individual tumblers of the series of tumblers 16 may slide in a vertical direction, but spring 17 acts between upper and lower lug portions 20, 21 on the tumblers to press them toward the dispersed position shown in FIG. 1. The assembled key plug 10 and series of tumblers 16 will be mounted for rotation in the bore of a cylinder 19, FIG. 2. I believe that the particular tumbler mounting and spring arrangement need not be described in further detail because the arrangement will be recognized by those skilled in the art, and I shall proceed to describe the novel construction of my lock.

As may be seen in FIGS. 3 and 5 of the drawings, I form the cylinder 19 with a pair of locking grooves 22 extending longitudinally in opposed upper and lower surfaces of the cylinder bore, and I further form a locking groove 23 in a lateral surface of the bore. In order to understand the particular relation between the series of tumblers 16 and the locking grooves 22 and 23, it will be best to observe first that I equip the key plug 10 with a side bar 25 for engaging the locking groove 23. The side bar 25 extends substantially the full length of the series of tumblers 16, as indicated in dotted lines in FIG. 2, and is mounted to slide in a lateral direction in an opening 26 in the side of key plug 10.

I particularly utilize a spring 27, which I show as a U-shaped spring mounted in an opening 28 in the cylinder 19, that presses the side bar 25 toward a release position aligned with the peripheral surface of key plug 10, FIG. 5. Movements of the side bar 25 will be controlled through a cam pin 29 that is assembled behind the side bar.

The series of tumblers 16 includes certain tumblers 16a that I shall describe while referring to FIGS. 3 and 5. Thus, each tumbler 16a has opposed locking portions 30 for engaging the cylinder grooves 22. Those portions 30 are proportioned so that their end surfaces 31 may lie substantially in aligned relation to the peripheral surface of key plug 10, as in FIG. 5. Further, I cut away a side of each tumbler 16a so as to form a clearance portion 32 that will prevent a transfer of pressures between tumbler 16a and the cam pin 29. A medial part of tumbler 16a is formed with an opening 33 that presents a surface for engagement by the bitted portion of a key K that may be inserted through the keyway 12, FIG. 2.

There are other tumblers 16b, one of which is shown in FIG. 4 and indicated partly in dotted lines in FIGS. 3 and 5. Each tumbler 16b has a side surface 34 for engaging the cam pin 29, and a cam groove 35 that is formed in the surface 34 for accepting the pin 29, as in FIG. 5. The cam groove 35 is so formed as to propel the cam pin 29 when the tumbler slides, placing the side bar 25 in locking position in cylinder groove 23, FIG. 3. The tumbler side 34 then will hold the bar in locking position. As do the tumblers 16a, tumblers 16b have a medial keyway opening 33. However, tumblers 16b Will not engage a cylinder groove 22, being formed with end surfaces 36 that normally have clearance relatively to the cylinder bore and that will not enter the grooves 22.

A properly bitted key K that is inserted through keyway 12 and into the tumbler openings 33 will set all of the tumblers in a release position which is shown in FIGS. 2 and 5. The key K merely need be a standard type of key having a simple bitted portion. It will be understood that the tumbler openings 33 may be formed in varying positions in the tumblers in order to form tumbler combinations that will be set by different keys. Also, if so desired, the cam grooves 35 may be formed in varying positions on the sides 34 of tumblers 16b. Actually, there need not be a great variety of tumblers, because I can achieve numerous combinations merely by assembling a few varying forms of tumblers in different sequences in the stack of tumblers 16.

Further, the quantity of tumblers 16a need be in no particular proportion or sequence relatively to the quantity of tumblers 16b. Merely for purposes of disclosure, I show the series of tumblers 16 assembled with tumblers 16a and 16b in alternating order, and it is to be understood that my invention is not so limited.

To explain the operation of my lock, I shall first call attention to the fact that hairpin spring 17 will press the series of tumblers 16 to locking position, FIG. 3, but the side bar 25 is held against its spring pressure when in locking position. The tumbler portions 30 then engage one or the other of the cylinder grooves 22, and side bar 25 engages cylinder groove 23. The key K will :act against the spring pressures of the series of tumblers 16 so as to place them in release position, FIGS. 2 and 5, while side bar 25 moves by its spring pressure to release position.

Naturally, the series of tumblers 16 can be moved against its spring pressure by means other than a key, as by a picking tool that may be inserted in the keyway 12. On the other hand, the side bar 25 when in locking position will not be moved by a tool and can move only by its spring pressure. Further, picking torque that may be applied to key plug will tend to grip the side bar between key plug 10 and cylinder 19, holding the side bar more firmly in locking position. Therefore, should it be found possible through the picking torque to set the tumbler end surfaces 31 in release position at the periphery of the key plug, the torque will prevent a release movement of side bar 25. In effect, the torque will remove the spring pressure from the tumbler sides 34, so that the particular pressure may not be utilized when trying to pick the tumblers. At least some of the tumblers 16b that have a cam groove 35 do not coact with the cylinder grooves 22, and therefore cannot be picked through a procedure that requires contact between a tumbler and a cylinder.

When the series of tumblers 16 is in a locking position extending from the peripheral surface of key plug 10, with the tumbler portions 30 extending a greater or lesser distance into a locking groove 22, those portions will effectively lock the key plug against rotation. The locking will be effective though the tumbler portions 30 may be near a release position, and extend only a very short distance into the groove 22. As will be appreciated, the tumblers then prevent operation of the lock by a key that is perhaps nearly the same as the proper key. Thus, my lock will prevent key interchange.

I believe it will now be understood that the concept of my invention utilizes tumblers that are spring pressed to locking position and a locking member that is spring pressed to release position. The tumblers engage the lock cylinder while also controlling the locking member, contributing both a direct and an indirect locking action. The tumblers will prevent key interchange, and will very effectively confuse a picking procedure that may be utilized, so that it will be practically impossible to pick the tumblers. I achieve these things while utilizing tumblers that will be made to yield numerous combinations simply through varying the order in which they are assembled, and that will merely require a standard type of key. I believe, therefore, that the very considerable value of my novel lock will be understood, and that the merits of my invention will be fully appreciated by those skilled in the art.

I now claim:

1. In a lock, a lock cylinder, a key plug rotatable in a bore in said lock cylinder, a series of tumblers mounted each for movement in said key plug and adapted to be positioned by bitted portions of a key inserted in a keyway formed in said plug, side bar locking means positioned between a locking groove in said cylinder and sides of said tumblers, said side bar locking means having opposed surfaces formed to engage with a relatively close fit between surfaces of said locking groove so as to hold the key plug against movements due to torque that may be applied to the plug, spring means pressing said side bar locking means toward the tumbler sides, certain tumblers of said series of tumblers being of that type adapted to be moved into a position aligning end surfaces thereof with the periphery of the key plug for releasing the key plug for rotation and thereby vulnerable to a degree to picking upon the application of picking torque to said key plug, the key plug supporting each of said certain tumblers in clearance relation to said side bar locking means so as to permit no transfer of pressures between those means and tumblers, others of said tumblers positioned by the same key and formed in their sides with cam grooves into which said side bar locking means will move by its spring pressure for releasing said key plug for rotation in said cylinder, and spring means pressing each of said other tumblers toward a position expelling said side bar locking means from the cam groove in that tumbler, so that all of said other tumblers must be held by a key to permit the locking means to remain in the cam grooves.

2. The combination of claim 1, in which said series of tumblers is aligned in a longitudinal direction relatively to the key plug, and the side bar locking means substantially extending the entire length of the series of tumblers.

3. The combination of claim 1, in which each of said certain tumblers comprises a disc on which is a locking portion that has an end surface adapted to align with the key plug periphery, and a cut away portion contributing clearance between the disc and side bar locking means.

4. In a lock, a lock cylinder, 8. key plug rotatable in a bore in said cylinder, a series of tumblers movable in the key plug and spring pressed to a position engaging be tween the key plug and cylinder whereby to lock said plug against rotation in the cylinder bore, a locking member adapted to engage a locking groove in the cylinder and spring pressed toward a release position in the key plug, said locking member having opposed surfaces formed for engaging with a relatively close fit between surfaces of said locking groove so as to hold the key plug against movements due to torque that may be applied to the plug, said series of tumblers being formed with side portions controlling the movements of the locking member, and end portions that lie at the peripheral surface of the key plug when the tumblers are in release position, said side portions comprising cam grooves through which the series of tumblers by its spring pressure acts when moving to position locking the key plug to move the locking member against its spring pressure and to position engaging the locking groove, the key plug supporting certain tumblers of said series of tumblers in clearance relation to the locking member so as to permit no transfer of pressures between said locking member and said certain tumblers, and surfaces on said series of tumblers engaged by a key inserted into a keyway of the key plug for setting said series tumblers in a release position.

5. In a lock, a lock cylinder, a key plug rotatable in a bore of said cylinder, 2. series of tumblers movable in the key plug and aligned longitudinally of the key plug, surfaces formed on the series of tumblers for engagement by a single bitted edge of a key that is inserted in a keyway in the key plug for setting the tumblers, certain tumblers of said series of tumblers having a portion for engaging between the key plug and an opening in the surface of the cylinder bore whereby to lock the key plug against rotation, side bar locking means movable on said key plug for engaging a locking groove in said cylinder, said side bar locking means and said certain tumblers being mounted in a clearance relation preventing a transfer of pressure between those means and tumblers, and surfaces on other tumblers of said series of tumblers coacting with the side bar locking means to control the movements of those means.

6. The combination of claim 5, in which said other tumblers of the series of tumblers are formed with side surfaces for holding the side bar locking means engaged with the locking groove in the cylinder, cam grooves in said side surfaces for accepting said side bar locking means, and spring means pressing the side bar locking means into said cam grooves when the tumblers are set by a key.

7. The combination of claim 6, in which said other tumblers and said certain tumblers of the series of tumblers are discs that are independently slidable and that are arranged in a stack in an opening in the key plug.

8. The combination of claim 7, in which the discs of said certain tumblers are formed with cut away portions contributing clearance relatively to the side locking means, and in which said other tumblers that coact with the side bar locking means are formed to maintain clearance relatively to the cylinder bore opening that is engaged by said certain tumblers.

References Cited UNITED STATES PATENTS 3,002,268 10/1961 Spain 29--428 3,035,433 5/1962 Tcsta -364 MARVIN A. CHAMPION, Primary Examiner R. L. WOLFE, Assistant Examiner U.S. Cl. X.R. 70-377, 421

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