US 3479849 A
Description (OCR text may contain errors)
Nov, 25, 1969 MM. CHECK PIN TUMBLER SIDE BAR CYLINDER LOCK Filed Oct. 20, 1967 3m INVENTOR. 'TfimTl-nes Q H BY CW -Ww ATTORN El United States Patent 3,479,849 PIN TUMBLER SIDE BAR CYLINDER LOCK Mathias M. Check, 34 Bowman Drive, Greenwich, Conn. 06830 Filed Oct. 20, 1967, Ser. No. 676,901 Int. Cl. Eb 27/08, /14
43.5. C]. 70-364 10 Claims ABSTRACT OF THE DISCLOSURE A new pin tumbler, side bar cylinder lock using a pivoting side bar locking device that pivots into the groove of the change pin to affect a locking action in the shell of the cylinder lock.
The present invention relates to a pick-resistant pin tumbler cylinder lock employing the side bar locking principle.
An object of the present invention is to provide a locking side bar of relatively simple construction which effectively prevents a cylinder lock from being picked by an individual applying a picking torque to the cylinder or plug.
An option of the present invention is to provide a holddown spring which straddles the side bars on either side of the change pin and applies pressure to the side bars to maintain the same in the proper effective pivotal position. This hold-down spring is not absolutely necessary except as one may desire further support to the side bars where 360 plug rotation and heavy duty service is anticipated.
Another object of the present invention is to provide a high security pin tumbler lock in which some of the pins are of the conventional type while the remaining pins are provided with pick-resistant side bars constructed in accordance with the teachings of the present invention. This arrangement is especially desirable when a great number of key changes are required over the number of key changes obtained in a full side bar locking construction and further, where key interchange is desired to be eliminated. The term key interchange describes a condition where two keys which are closely bitted to each other, might permit unintentional opening of another unmated lock. The side bar arrangement can also be used in combination with other various types of plain or grooved mushroom pin tumblers, disc or wafer tumblers found in other locks.
FIG. 1 is a partial sectional and a partial elevational view of the pick-proof cylinder lock taken along the lines 11 of FIG. 4 and employing a side bar constructed in accordance with the teachings of my invention, with the proper key in the keyway.
FIG. 2 is a partial sectional and a partial elevational view of the pick-resistant cylinder lock shown in FIG. 1 taken along the lines 22 of FIG. 4 with the side bar in the locking position, which would be the condition when no key was inserted in the keyway.
FIG. 3 is a view taken through lines 3-3 of FIG. 4 illustrating the details of the hold-down spring.
FIG. 4 is a perspective cut-away view of a pin tumbler cylinder lock showing the first three pins producing a condition as illustrated in FIG. 1 and with the fourth pin shown producing the condition illustrated in FIG. 2.
FIG. 5 is a partly cross-sectional and partly elevational view of an entire pin-tumbler cylinder lock in which some of the pins are of the conventional type while other of the pins utilize side bar locking devices.
FIG. 6 is a partial sectional and partial elevational view of alternate means for pivoting the side bar locking device.
FIG. 7 is a detail in perspective of the pivoting means illustrated on the right hand side of FIG. 6.
Referring to the drawings, the present pin tumbler cylinder lock has an outer shell 10 and inner rotatable cylinder or plug 12. As is well known, the shell 10 is provided with a series of pin holes 14, each having a drive pin 16 which is urged by a spring 18 toward one of the corresponding pin holes 20 in the cylinder 12. Located in the pin hole 20 are change pins 22 and 22a, the change pins 22 co-acting with the side bar are provided with angled or conical grooves 24. The parting line between the shell 10 and the cylinder 12 is identified by the reference numeral 26.
The cylinder 12 is cut-away to form a recess 28 in which is located a side bar 30 having a generally L- shaped configuration with legs 30a and 30b. Also located in recess 28 is a side bar spring 32 which is housed within the confines of the outer shell 10 and has its end 32a in the apex of the angle formed by legs 30a and 30b of side bar 30. The side bar spring 32 therefore ensures the proper pivoting of the side bar 30 when the leg 30a of the side bar drops into tthe groove 24 of the change pin 22, all as seen in FIG. 1.
It should be noted from FIG. 1 that when the correct key K is inserted in the keyway of the cylinder 12 the change pin 22 is raised to a point where the side bar 30 meshes with or enters the groove 24. When this occurs, the leg 30b of the side bar 30 falls within the perimeter of the key cylinder or plug 12 permitting the cylinder to rotate freely in outer shell 10. The side bar spring 32 assists in constantly urging the side bar leg 30a into abutting engagement with the groove 24 of the change pin when the proper key is in the keyway. However, when no key exists in the keyway or if an improper key is inserted in the keyway, the condition as shown in FIG. 2 of the drawing occurs. When no key exists in the keyway, the drive pin 16 and the change pin 22 are forced downwards in the pin holes 14 and 20 respectively fully locking the cylinder 12 by the side bar locking principle. The leg 30a of the side bar 30 abuts the straight face of the drive pin 16 and the leg 30b of the side bar 30 is raised to project into the locking notch 34 in the outer shell 10. In this condition, the key plug or cylinder and shell are locked together thereby preventing rotation of the key plug or cylinder 12. Applying a picking torque to the key plug will also prevent further rotation of the plug. This is so inasmuch as the side bar 30 is dogged between the surface A of the drive pin and/or point C of the cylinder plug and shell and the surface B of the outer shell 10 as long as picking torque is maintained on the plug. This dogging prevents rotation of the key plug or cylinder 12 even if the change pins 22 are properly positioned, thus a pick-resistant lock construction is achieved.
When the option is exercised to maintain the side bars 30 in their proper, effective pivotal position, where heavy duty service is anticipated, a hold-down spring 36 may be inserted in the key plug or cylinder 12 as shown in FIG. 3. The spring 36 is located in grooves 31 of the side bars 30 and straddles the side bars 30 thereby applying pressure to the latter. This arrangement prevents the side bar 30 from partially entering the locking notch 34 when the side bar is rotated in the unlocked position. FIG. 4 shows one of the side bars 30 in the locking position while the other side bars 30 are in the unlocked position.
FIG. 5 illustrates the complete locking cylinder 12 together with a plurality of pin tumblers in which the first two pin tumblers are of the conventional type while the last three pin tumblers are provided with my novel side bar locking device. This arrangement is desirable when a greater number of secure key changes are required than with a full side bar locking construction.
It should also be noted that another option is offered in FIG. 5 for the purpose of providing greater locking security. It should be evident that the length of the conventional key is designated 'by the arrow R while the length of the key used in the present key cylinder 12 is designated by the arrow T. The length T is shorter than the length R. The key K with the length T is provided with a sharply sloping end S which engages the last change pin 22 so that a slight manipulation of the key, such as withdrawing the key slightly from the keyway, will cause the last change pin 22 to drop sharply in the pin hole and thereby ensure locking of the key plug 12 to the outer shell 10. Obviously, the construction shown in FIG. 5 will foil an attempt by a lock picker to manipulate a key which is only slightly different from the proper key. I
In that case the lock picker attempts to align the pins properly at the parting line and thereby rotate the key plug 12 by minutely adjusting the key in the keyway. In the present construction even a slight withdrawal of the key in the keyway will cause the relative change pin to drop sharply in the respective pin hole thereby securely locking the key plug and the shell together. It should also be understood that the use of a shorter key is not mandatory to the proper working of my side bar lock.
It should also be apparent that the specific arrangement illustrated in FIG. 5 is particularly suitable for masterkeying.
FIG. 6 shows alternate means for pivoting the side bar 30. In the right hand side of FIG. 6 a finger 38 preferably integral with key plug 12 has an end portion 38a which projects in recess 28 of the key plug and engages at the junction of the legs 30a and 30b of the side bar 30. The side bar therefore pivots on the end portion 38a. In the left hand side of FIG. 6 the side bar 30 is provided with axle portions 37 which nest in complementary grooves in the key plug 12 so that the side bar 30 may pivot in a manner described hereinabove. The details of construction of the axle portions 37 are particularly illustrated in FIG. 7.
What I claim is:
1. A pin tumbler lock comprising an outer shell, a rotable key plug in said outer shell, a plurality of pin holes in both said key plug and outer shell having co-acting drive pins and change pins therein, at least one of said change pins being provided with a groove in a side surface thereof, a recess in said key plug extending from the pin hole in which the grooved change pin is mounted, a locking notch in said outer shell extending from said pin hole and facing said recess, a pivotal side bar locking device located at least in said recess, resilient means co-acting with said side bar locking device when one portion of said side bar locking device engages the side surface of said drive pin outside of said groove to apply moments of force on said side bar locking device whereby part thereof engages positively the marginal edge of said locking notch adjacent to said drive pin to thereby pivot said side bar when said portion thereof enters into the groove of said change pin whereby the entire side 'bar is within the perimeter of said key plug permitting free rotation of said key plug within said outer shell, and when said one portion of the side bar engages said side surface of said change pin said side bar pivots to cause another portion of said side bar to project into the locking notch in said outer shell thereby preventing rotational movement of said key plug in said outer shell.
2. A pin tumbler cylinder lock as claimed in claim 1 whereby said side bar locking device is of an L-shaped cross-section and said parts of the side bar are separate legs thereof.
3. A pin tumbler cylinder lock as claimed in claim 1 wherein said resilient means is a spring having one end engaging said side bar at the junction of said legs.
4. A pin tumbler cylinder lock as claimed in claim 1 wherein said groove in said change pin is conical-shaped.
5. A pin tumbler cylinder lock as claimed in claim 1 wherein at least one of said change pins is provided with a smooth, uninterrupted outer surface while another of said change pins has said groove in a side surface thereof. said side bar being only operative with the other change pin having said groove.
6. A pin tumbler cylinder lock as claimed in claim 1 further comprising spaced axle portions on said side bar and at least one complementary groove in said key plug whereby said axle portions nest in said groove to permit pivotal movement of said side bar.
7. A pin tumbler cylinder lock as claimed in claim 1 further comprising a finger portion on said key plug projecting at least partially into the recess of said key plug, said side bar being seated on the end of said finger portion in a manner whereby said side bar is capable of pivotal movement thereon.
8. A pin tumbler cylinder lock as claimed in claim 6 further comprising a hold-down spring, said side bar being provided with a groove in which part of said holddown spring is located therein whereby said side bar is held out of the operational area of said locking notch when said part of the side bar engages in the groove of said change pin.
9. A pin tumbler cylinder lock as claimed in claim 7 further comprising a hold-down spring, said side bar being provided with a groove in which part of said holddown spring is located therein whereby said side bar is held out of the operational area of said locking notch when said part of the side bar engages in the groove of said change pin.
10. A pin tumbler lock as claimed in claim 1 wherein said resilient means is a spring which exerts a compound force on said side bar locking device having one vector of force in a direction transverse to the longitudinal axis of said change pin and another vector of force at an acute angle to said first force.
References Cited UNITED STATES PATENTS 2,023,847 12/1935 Liss -362 2,426,104 8/1947 Johnstone 70421 2,524,339 10/1950 Young et a1 70366 MARVIN A. CHAMPION, Primary Examiner R. L. WOLFE, Assistant Examiner US. Cl. X.R. 70366. 378. 419