US2993361A

US2993361A - Pin tumbler lock

Info

Publication number: US2993361A
Authority: US
Inventors: Leo E Van Lahr
Original assignee: Individual
Current assignee: Individual
Priority date: 1959-08-10
Filing date: 1959-08-10
Publication date: 1961-07-25
Anticipated expiration: 1978-07-25

Description

July 25, 1961 E. VAN LAHR PIN TUMBLER LOCK Filed Aug. 10, 1959 1 l a r- INVENTOR. (ea 5. Van Zak! Ohio Parkit-Lockit 60., 3609 *Church St., Cincinnati 44, Ohio) Filed Aug. 10, 1959, 'Ser. No. 832,571 3 Claims. (Cl. 70-363) The present invention relates to an improved pin tumbler lock and has for its principal object the provision of a novel, severable connecting means between a lock of the indicated type and its operating key which establishes and controls the rotatable home position of said key on the pin tumbler lock.

Another object of the invention is to provide a rugged freeze proof, tamper proof and dust proof pin tumbler lock that can readily be disassembled and which is particularly adapted for use with coin operated equipment where security is important, reliable performance a necessity and the flexibility of changing lock and key permutations a desirability.

A further object of the invention is to provide a lock and key severable connecting means comprising an exterior, key engaging slot located on the exposed surface of the lock case, rather than in the case and/or the rear of the case, which will secure the production of a look having the next preceding characteristics.

A still further object of this invention is to provide a lock construction that may be built on a reduced scale and of a comparatively smaller size than locks now in use whilst increasing the ruggedness of the lock and the facility of changing the lock and key permutations.

Other objects of the invention will be apparent from the following description taken in conjunction with the accompanying drawing showing a preferred embodiment of my invention, and wherein:

FIG. 1 is a longitudinal sectional view taken through a lock and a key illustrative of my invention, and showing the key bit about to be associated with the lock.

FIG. 2 is a plan view of the key bit shown in FIG. 1.

FIG. 3 is a plan view of the lock illustrated in FIG. 1.

FIG. 4 is a fragmental, side elevational view of the lock shown in FIGS. 1 and 3.

FIG. 5 is a view similar to FIG. 3, showing a modification of the lock, a part being broken away and shown in section.

The lock illustrated in the drawings is operable by an adjustable key 11 and is of the type in which the tumblers are movable parallel to the axis of the tumbler plug. With reference to FIGS. 1, 3 and 4 it will be noted that the lock has a hollow, cylindrical case 12 provided at its forward, open end with a circular, radially projecting flange 13 and an annular key engaging portion 14 extending forwardly from the flange 13. The 'lock case has a large bore 15 formed concentrically in its forward portion and a communicating smaller bore 16 formed through its rear portion which provide an annular forwardly facing, planar shoulder 17 intermediate the lock case ends which is positioned normal to the longitudinal axis of the case and which serves to determine the shear plane of the pin tumblers. As best shown in FIG. 4 the rear exterior portion of the lock case may have threads 18 formed therein that may be interrupted by opposed flats 19 and which co-operate with the flange 13 and a nut 200, or other device, to mount the lock case on a closure 20, or other suitable member.

A two-diameter plug 21 is journaled for rotation in the hollow case 12 and comprises a large, cylindrical forward portion 22 rotatable within the forward bore 16 in the case and having a small cylindrical rear portion 23 rotatable in the small bore 16, the latter portion Patented July 25, 1961 23 on the plug having an externally threaded shank 24 integral therewith and extending rearwardly therefrom beyond the case. As is indicated in FIGS. 1 and 4 the shank is provided with a pair of opposed flats 25 that engage an irregular hole in a latch dog 26, said dog being mounted a desired distance behind the case by a suitable sleeve 27 and being held thereagainst by a nut 28 threaded on the shank 24. It will, therefore, be noted with reference to FIG. 1 that the forward face of the large, cylindrical portion 22 of the plug 21 is flush with the forward circular face of the shoulder 14 and that the relatively wide shoulder 17 within the case provides a strong back up means for preventing driving of the plug through the case by blows directed against the plug from the outside by a person desiring to break the lock. A washer 29 is held against the rear face of the casing by a snap-on, spring fastener 30 snapped into a slot 31 between the shank 25 and the small cylindrical portion 23 of the plug, said washer and spring fastener precluding axial removal of the plug through the forward end of the casing.

A circular row of angularly spaced apart through holes 32 are formed in the case, said holes having their respective axes parallel to the axis of the plug and extending through the case body between the shoulder 17 and the rear face of the case. A corresponding row of angularly spaced apart holes 33 is formed through the body of the large cylindrical portion 22 of the plug 21 and are each provided with a reduced mouth portion 34 which is interposed between the forward end of the bore 33 and the forward face of the plug.

The rows of

holes

32 and 33 in the case 12 and the plug portion 22, respectively, are normally in aligned, locked positions and each of the aligned holes receive axially movable pairs 35 (FIG. 1) of pin tumblers, the outer tumbler of each pair having a reduced end 36 that snugly seats in the reduced mouth portion 34 in the plug. Each pair of pin tumblers is urged forwardly by an expansile spring 37 held in the hole 32 in the case and bearing at its forward end against the pair of tumblers, said spring being held in compression in the hole by the washer 29. It will, therefore, be seen that in normal locked position the forward reduced end 36 of each pair of pin tumblers will seat snugly in the mouth 34 in the plug 21 and have its outer end approximately flush with the forward face of the plug thereby precluding the entrance of ice, rain or dust into the interior of the case. It will also be appreciated that ice formation on this forward face may be readily scraped or chipped off by a suitable tool when required without injury to the lock parts.

The case is provided with one co-operable part of a severable key-to-lock connecting means, said one part consisting of a plurality of bayonet slots 38 formed in the cylindrical surface of the forward portion 14 of the case. As best shown in FIGS. 3 and 4 each slot has an entrance portion 39 which is parallel to the common axis of the case and the plug and a circular portion 40 concentric with said common axis, said slot communieating with the inner end of the entrance portion at right angles thereto and terminating a fixed circular distance from the said entrance portion.

The key 11 for my lock is shown in FIGS. 1 and 2 and includes a bit member '41 having a circular flat base 42 that has a continuous skirt 43 projecting downwardly from the periphery thereof and at right angles thereto. The skirt has an inside diameter that is slightly larger than the outside diameter of the forward cylindrical part 14 of the case and is adapted to surround the said case portion when the key is axially moved to its home position on the lock. A circular row 44 of tumbler actuating pins of different lengths project from the base 42, the pins 44 corresponding in number and position to the pairs of tumblers in the plug 21. As best shown in FIG. 1 each pin has an enlarged boss 45 and projects through a hole 46 formed in the base '42 of the key bit portion. A means for removably securing the pins 44 in the bit portion comprises a circular head 47 and a peripheral downturned skirt 48 formed on the head and projecting therefrom a distance equal to the thickness of the boss 45. An irregularly shaped, integral lug 49 is formed centrally in the head =47 and fits into an irregular hole 541 in the base 42, the head and the base being secured together by a screw 51 countersunk in the base 42 and threaded in the head 47. The key is manipulated by a finger portion 52 integrally joined to the central part of the head 47.

The complementary part of the severable, key-to-lock connection comprises a series of angularly spaced apart lugs 53 projecting radially inwardly from the inside face of the skirt 43 on the bit portion 41 of the key, said lugs corresponding in number and positions to the entrance portions 39 of the bayonet slots 38 in the forward cylindrical part of the case.

In operation it will be understood that the key is moved axially from its position with respect to the lock, shown in FIG. 1, to a home position wherein the skirt 4-3 of the key bit member 41 surrounds the cylindrical portion 14 of the lock case. In moving to this home position the several lugs 53 on the bit member '41 of the key move through the entrance portions 39 of the bayonet slots 38 in the case whilst the pins 44 enter their respective holes 34 in the plug 21 and depress their respective tumbler pairs 35 until the abutting surfaces of the pairs lie in the shear plane of the shoulder 17. The plug may now be rotated by the key in the case, the amount of rotation being limited by the radial portions 40 of the slots in which the lugs move during said limited relative rotation.

Now referring to FIG. of the drawings which illustrate a modification of my lock it will be seen that a continuous, annular slot 54 is formed in the exposed key engaging portion 14 of the lock case 12 and that two entrance slots 55 are formed in said portion 14 which communicate with opposite portions of the slot 54. The key for this modified lock is identical to the key shown in FIGS. 1 and 2 of the drawing except that it has two oppositely positioned lugs in the skirt interior instead of the three lugs 53, as shown. This continuous, annular slot 54 is utilized where a screw type lock is desirable and it is further contemplated that this type of slot could be ideally employed in looks which have built in stop means limiting rotation of the plug in the case or where the plug and case have cooperablestop means on the rear portions thereof.

The illustrated lock and the key structure has many advantages over conventional pin tumbler locks in that the key bit pins and the pin tumbler permutations may be easily changed and especially in the provision of the severable means for engaging the key and lock in their home positions for controlling the limits of relative rotation between the plug and case when the key operates said plug.

While I have shown a particular embodiment of my invention, it will, of course, be understood that I do not wish to be limited thereto, since various modifications may be made in the key and lock constructions without departing from the spirit and scope of my invention as set forth in the appended claims, and I contemplate by the appended claims to cover any such modifications as fall within the true spirit and scope of my invention.

What is claimed is:

1. In a tumbler lock, a hollow cylindrical case having a large forward bore and a co-axially positioned small bore in the rear part and communicating with said forward bore, a forwardly facing shoulder within the case between the bores and disposed at right angles to the common axis of the bores, a plug having an enlarged forward end rotatable in the large forward bore and having a forward face flush with the forward face of the case, said plug having a small rear portion rotatable in the rear bore, means on the plug engaging the rear end of the case for precluding axial movement of the plug through the forward part of the case, a row of angularly spaced apart holes formed in the plug and having restricted mouths communicating with the forward face of the plug, the case having a row of angularly spaced apart holes normally in alignment with corresponding holes in the plug, said aligned holes of the case passing through the forwardly facing shoulder and disposed parallel to the axis of the plug, a pair of pin tumblers in each of said aligned holes in said plug and case, the forward end of each pair of tumblers being adapted to normally seat in the restricted mouth in the plug, spring means in each hole of the case urging a pair of tumblers forwardly, and bayonet slots formed on the forward portion of the case, said slots having an entrance portion parallel to the axis of the case and a circular portion disposed at right angles to the entrance portion and concentric with the said axis of the plug.

2. In combination a tumbler lock having a hollow cylindrical case provided with a forward bore and a coaxially positioned small bore formed in the rear part of the case and communicating with the forward bore, a plurality of pin tumblers arranged parallel with the axis of the case, a plug having an enlarged forward end rotatable in the large forward part of the bore and having a forward face flush with the forward face of the case, means on the plug engaging the rear end of the case for precluding axial movement of the plug through the forward part of the case, the forward part of the case having bayonet slots formed therein and including an entrance portion parallel to the axis of the plug and case and a circular portion at right angles to the entrance portion, a key having bit pins adapted to operate the pin tumblers, said key having an annular skirt surrounding the bit pins and adapted to encircle the cylindrical forward end of the case, and inwardly directed lugs formed on the skirt for engaging the entrance portions of the slots in the case when the key is moved to its home position on the lock case and moving in the circular portions of the bayonet slots to control the rotary movement of the plug in the case.

3. In combination a tumbler lock having a hollow cylindrical case, an annular key engaging portion formed on the forward end of the case, a plug rotatable in the case, pin tumblers movable in the case and in the plug parallel to the common axis of said case and plug, an exterior, circular slot formed laterally in the key engaging forward end of the case, a longitudinal entrance slot formed in said case end to establish communication between the forward face of the case and the circular slot, a key having bit pins adapted to operate the pin tumblers, said key having an annular flange surrounding the bit pins and adapted to encircle the annular key engaging portion of the case, and an inwardly projecting lug mounted on the flange for engagement in the entrance slot when the key is moved to its home position on the lock and moving in the circular slot to control relative rotation of the key and the lock case.

References Cited in the file of this patent UNITED STATES PATENTS 240,397 Ehmer Apr. 19, 1881 1,494,765 Barrett May 20, 1924 1,718,130 Frischmuth June 18, 1929 1,984,202 Shinn Dec. 11, 1934 2,588,230 George Mar. 4, 1952