US2375682A - Cylinder lock - Google Patents

Description

P. W. OLSON CYLINDER LOCK May '8, 1945.

Filed April 8, 1943 n W PW y Y. a

PW 11/. azs BY Patented May 8, 1945 UNITED STATES PATENT OFFICE, h g 2,375,682

. CYLINDER were Phillip W. Olson, Chicago, 111.. Application April s, 1943, Serial No. 482,346

2 Claims. This invention relates in general to looks and more particularly to a tumbler type cylinder lock highly resistant to .picking.

So-called pick-proof locks prior to this invention usually were dependent upon a large number of tumblers or other complicated means i for their securityiand resistance to picking, which construction is expensive, whereas the novel construction of the present invention includes simple means whereby the use of relatively few tumblers and correspondingly low manufactuing cost provide ample security and high degree ofresistance to picking.

Ihe principal object of the invention is to provide a tumbler lock including a plurality of relatively few detent-controlled tumblers.

A further object of the invention is the provision of a cylinder lock having detent-controlled.

i 9 Further object and advantages of the invention will be apparent inone embodiment hereinafter described, in which: 7

Fig. 1 is a side elevation of the lock assembly. Fig. 2 is a typical key for operating the lock shown Fig. 1. i

Fig, 3 is an enlarged cross-sectional view of the lock taken through section lines 33, Fig. 1.

Fig. 4 is. an enlarged cross-sectional View of the key takenthrough section lines 4-4, Fig. 2.

Fig. 5 is an enlarged perspective view of the tumbler elements of the lock.

Fig. 6 is an enlarged cross-sectional elevation of the lock taken through section lines 6-6, Fig. 3 and showing the key in proper relation to the For the purpose of illustration, the type lock shown anddescribed is for the use of a key having unrelated serpentine grooves in its oppo-. site sides, and although this showing is a preferred construction, it will appear from the following description that locks for other type keys are equally applicable. i

Referring to Fig. 1, the barrel or housing I serves to retain the elements of the lock. .A cap 2 closely fitted over the barrel contains the keyhole. A conventional bolt 3 is integrally secured to the rotatable cylinder 4 and is adapted to engage a strike plate, not shown.

Referring to Figs. 2 and 4, the key 5 is provided with a rectangular shank 6 having unrelated sernormally would unlock the bolt 3 from a strike pentine grooves l in each side thereof. The barrel I has in'its inside periphery, two pair of oppositely disposed grooves 8 running parallel to its axis.

A cylinder 4 is constructed of two half sections and held together by means of two snap rings 9 fitting in appropriate grooves in each end of thefcylinder, shown in Fig. 6. The cylinder is adapted to rotate freely within the barrel l. A cylindrical projection ll! of the cylinder extends through a bearing ring I l which is retained in proper position by a snap ring 12. The bolt 3 is integrally attached to the end of the projection t In for locking purposes.

Referring to Fig. 5, each tumbler I3 is provided with a detent projection l4 and a key follower 15 positioned opposite the detent. The key follower in each tumbler is positioned to correspond with a predetermined formation of the serpentine grooves I in the keypthe action of which will be hereinafter described. Each tumbler is placed in its corresponding slot IS in the cylinder 4 which extends through the cylinder at right angles to the axis of rotationof the cylinder.

A detent plunger IT having a Pointed end and a spring IB are retained in the cylinder in an appropriate hole IS. The pointed end of the plunger is adapted to slidably engage the detentv projection M of each corresponding tumbler.

It is now apparent from Fig. 3 that each tumbler is capable of reciprocable movement in its slot l6 and that the plunger I! will urge the tumblerv in either direction depending upon its initial movement over the central point of the projection.

In operation and assuming that the key followers l5 have been positioned to suit a corresponding key, it will be seen from Fig. 6 that one end of each tumbler will engage a groove 8 and thus prevent the cylinder 4 from turning in the barrel 1. When the key shown in Fig. 6 is inserted, the lateral surfaces of the serpentine groove 1 will engage the key followers l5 and Withdraw each tumbler a predetermined distance to free its end from the grooves 8 and thus enable the key to turn the cylinder 4 within the barrel I, which plate.

The usual practice of picking locks i dependent upon either vibrating or moving the tumblers and disengaging their ends from locking grooves. In the present invention any attempt at moving the tumblers to predetermined positions would be defeated by virtue of the detent action previously described, as it can easily be i seen if a particular tumbler is withdrawn sufficiently far to disengage one of its ends from the cylinder groove and the plunger l1 reaches the peak of the projection M of the tumbler, the plunger, urged by spring l8, will throw the tumbler in the opposite direction and thus engage the opposite end of the tumbler in the groove of the cylinder. Therefore, any attempt to operate or pick even a small plurality of tumblers without a key is impractical if not impossible.

Although the lock described herein shows three tumblers, it is to be understood that a smaller or larger number of tumbler may be used without departing from the scope of the invention.

Having described my invention, I claim: 1. A cylinder lock comprising a casing having a'key-operable rotatable cylinder afiixed therein, said casing having a plurality of tumbler slots therein, a plurality of key-operable tumblers slidslots, each'said tumbler provided with an integral detent projection, spring-actuated detent means for normally and independently engaging said therein, a plurality of key-operable tumblers slidably retained in saidcylinder, each end of said tumblers adapted to engage corresponding said bler in a corresponding said slot to lock said cyl-- inder to said casing.

- PHILLIP W. OLSON.

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