US3505838A

US3505838A - Locks and keys

Info

Publication number: US3505838A
Authority: US
Inventors: Jack William Taylor
Original assignee: Ingersoll Locks Ltd
Current assignee: Ingersoll Locks Ltd
Priority date: 1968-01-25
Filing date: 1968-01-25
Publication date: 1970-04-14
Anticipated expiration: 1987-04-14

Description

A ril 14, 1970 Filed Jan. 25 1968 J. w. TAYLOR LOCKS AND KEYS 2 Sheets-Sheet 1 lzvvggrok J. w. TAYLOR 3,505,838

LOCKS AND KEYS A ril 14, 1970 2 She'ts-Sheet Filed Jan. 25 1968 IN VE N770? United States Patent 3,505,838 LOCKS AND KEYS Jack William Taylor, Bournemouth, England, assignor to Ingersoll Locks Limited, London, England, a British company Filed Jan. 25, 1968, Ser. No. 700,611 Int. Cl. Eb 65/06, 21/02 US. Cl. 70-134 6 Claims ABSTRACT OF THE DISCLOSURE This invention relates to the type of lock in which the deadbolt is moved from the outward locked position to the inward unlocked position and vice-versa as the result of the insertion and rotation of a predetermined key, the operation of the key being to first align impediments to enable the deadbolt to move and then to/cause actual movement of the deadbolt. Heretofore in locks of the type described the mechanism is generally deficient in security against violent attack, such as by side thrust and end pressure exerted against the deadbolt, and is restricted in the length of the throw of the deadbolt therefore in the amount of engagement of the deadbolt in the locking plate. Such locks also cause inconvenience in operation by the key due to the relatively short backset or distance from the front of the lock to the keyhole. When the backset is of ample dimension to ensure clearance for operation the application of these locks is restricted by the size of the lock. An object of this invention is, therefore, to improve the security of locks of the type described by providing a mechanism to withstand considerable violent attack, said locks being of such relatively small size to be suitable for general application and having the mechanism distance from the front of the lock to the keyhole according to the size of the lock case.

A lock of the type set forth including a lock casing, a number of levers or other impediments mounted in said casing and movable as a result of turning movement of the appropriate key in the lock, a deadbolt or locking type springbolt movably mounted in said casing, a cam lever pivotally mounted in said casing and engaging said deadbolt or springbolt to move the latter into or out of its locking position, said cam lever being moved by said key and means for preventing movement of said deadbolt or springbolt until all the levers or other impediments have been moved the appropriate amount by the correct key, said deadbolt movement preventing means comprising a bell-crank lever pivotally mounted within said casing, one end of said bell-crank lever engaging said cam lever to prevent unauthorised movement thereof, the opposite end of said bell-crank lever being enterable into notches in said levers or impediments when said notches are all aligned as a result of movement of said levers or impediments by the correct key, in which case the opposite end of said bell-crank lever can move clear of said cam lever to permit movement of said cam lever and deadbolt or springbolt under turning movement of the key.

Referring to the accompanying drawings:

FIGURES 1 to 5 are sectional front elevations of a lock in accordance with the present invention showing the deadbolt in process of being moved from its projected operative position to its withdrawn inoperative position;

3,505,838 Patented Apr. 14, 1970 FIGURE 6 is a similar view showing the deadbolt in process of being projected;

FIGURE 7 is a sectional view showing a preferred form of pivot used in the lock;

FIGURE 8 is a plan view of the preferred form of deadbolt; and

FIGURE 9 is a front elevation of the cam lever.

The preferred form. of lock illustrated includes a casing 1 formed with a keyhole 2 on one or both sides for the entry of the key, the casing containing a linearly movable deadbolt 3 formed with a slot 4, the edges of which are in operative engagement with a guide pin 5 in the casing, the guide pin in addition to guiding the deadbolt forming a stop for limiting sliding movement of the deadbolt in either direction.

The deadbolt is preferably of the laminated form shown in FIGURE 8 and is formed with a slot or recess 6 of the shape shown.

The deadbolt is moved into and out of its operative shot position by a cam lever 7, the shape of which is more clearly shown in FIGURE 9, the cam lever being bored at 8 to receive a pivot 9 carried in the casing, the pivot preferably taking the form shown in FIGURE 7, the pivot comprising an internally threaded sleeve 10 secured in position within the casing by screws 11.

The cam lever 7 has a flat extremity 12 which when the deadbolt is in its shot position as in FIGURE 1 engages a flat surface 13 of the modified slot 6, any endwise pressure exerted on the deadbolt to move the latter out of its shot position being transmitted by the cam lever 7 to the pivot 9 without any tendency for the cam lever to turn about its pivot.

The casing contains a bell-crank lever 14 pivotally mounted about a fixed pivot 15, one end 16 of the lever being urged into engagement with a flat face 17 of the cam lever 'by a spring 18.

The opposite end 19 of the bell-crank lever 14 is designed to enter slots 20 in a series of levers 21 when the slots are all aligned consequent upon pivotal movement of the levers 21 under initial turning movement of the correct key, the key bit engaging the edge of a curved recess 22 in each lever and entering a notch 23 in the edge of the cam lever as in FIGURE 2 to move the latter angularly about its pivotal point into the position shown in FIGURE 3 in which a protuberance 24 on the cam lever engages the opposite end of the slot 6 in the deadbolt and as a result of further movement of the key and cam lever moves the deadbolt into its fully retracted position, FIGURE 4 showing the deadbolt almost retracted, the key bit being still in engagement with the cam lever and pivoted levers 21. On the key being turned still further, the deadbolt will be fully retracted and the cam lever moved into a position in which the cam face 25 on the cam lever allows the crank lever 14 to turn in a clockwise direction into a position in which the 0ppo site end 19 will withdraw from the aligned notches in the levers 21 and allow them to return to their initial position under the action of their associated springs 26 as in FIGURE 5, the key being withdrawn.

Levers 21 are pivotally mounted on a fixed pivot 27 in the casing and are formed with slots 28 which in conjunction with pivot 9 limit their angular movement.

In FIGURE 6 the key has been re-inserted and turned in the opposite direction to lift the levers 21 into a position in which their notches 20 are aligned to receive the end 19 of the bell crank lever. In this position the heel 29 on the cam lever engages the face 30 of slot 6 to move the deadbolt out of its retracted position.

As will be seen clearly in FIGURE 6, the lower end of the cam lever enters a well portion 30 of the slot 6 and fits fairly closely therein to avoid any free movement of the deadbolt.

The cam lever 7 is formed with a second cam face 31 which engages the bell crank lever to move it out of the notches in the levers in the event one or more of the springs 26 break.

The slot in the deadbolt may be as in FIGURE 8 or may be in the form of a recess from one side of the deadbolt. In FIGURE 8 the deadbolt is built up from laminations which are riveted and/or brazed or welded together, the inner laminations being cut away to form the slot.

Instead of a slot in the deadbolt a slot may be formed in the cam lever engaged by a pin or roller carried by the deadbolt.

Although pivoted levers are shown, the impediments may be of the linearly slidable type or the pin tumbler, wafer, lever or slider type.

The deadbolt may alternatively be mounted for pivotal movement and instead of the key being inserted directly into the lock casing it may be inserted in a bush revolvable in the casing. In such a case the bush may have an arm or projection for co-operation with the cam lever.

To protect the mechanism of the lock from the outside of the door the corresponding plate of the lock casing may be hardened or alternatively an additional plate of hardened steel may be attached or fitted to the corresponding plate of the lock casing.

It will be appreciated from the foregoing description that pressure exerted by an instrument on the deadbolt in an effort to force it back out of its shot position will result in pressure being applied to the pivot through the cam lever but not to the levers themselves and for this reason it is preferred to make the pivot as robust as possible whilst the levers themselves may be quite lightly constructed as metal pressings or stampings.

After the deadbolt has been retracted by operation of the correct key the deadbolt will be held firmly in its retracted position by the bell crank lever engaging the cam lever and also the key operated levers in such a Way as to prevent pivotal movement of the bell crank lever.

The construction of lock described is applicable to a lock operable from one side only or from both sides of a door.

I claim:

1. In an improved locking mechanism, the combination comprising, a lock casing, a group of levers mounted in said casing and movable as a result of turning movement of the appropriate key in the lock, at least some of said levers being notched, a deadbolt movably mounted in said casing, a cam lever pivotally mounted in said casing and engaging said deadbolt to move the latter into or out of its locking position, said cam lever being moved by said key and means for preventnig movement of said deadbolt until all levers have been moved the appropriate amount by the correct key, said deadbolt movement preventing means comprising a bell-crank lever pivotally mounted within said casing, one end of said bell-crank lever engaging said cam lever to prevent unauthorized movement thereof, the opposite end of said bell-crank lever being enterable into notches in said levers when said notches are all aligned as a result of movement of said levers by the correct key, whereby the opposite end of said bell-crank lever can move clear of said cam lever to permit movement of said cam lever and deadbolt under turning movement of the key.

2. In an improved locking mechanism as claimed in claim 1, wherein the pivot point of the cam lever is arranged to receive pressures exerted on the deadbolt during unauthorized attempts to move the deadbolt from an operative latch engaging position.

3. An improved locking mechanism as claimed in claim 1, wherein the deadbolt is formed with a slot for the entry of the end of the cam lever, the slot having a substantially flat face for engagement by a substantially flat face on the end of the cam lever when the latter is in its operative door locking position.

4. In an improved locking mechanism as claimed in claim 1, wherein the cam lever is formed with a notch for the entry of a part of the key bit to impart pivotal movement to the cam lever.

5. In an improved locking mechanism as claimed in claim 1, wherein the notched levers are spring-urged into engagement with the bell-crank lever, the cam lever being formed with a cam face for engagement with the bell-crank lever to move the latter clear of the notches in the levers in the event of failure of the spring associated with the notched levers when the deadbolt is in either its operative or retracted position.

6. In an improved locking mechanism as claimed in claim 1, wherein the pivot for the cam lever includes a large diameter sleeve located within the lock casing.

References Cited UNITED STATES PATENTS 1,544,893 7/19'25 Diebold "134 3,060,716 10/1962 Buffer 70134 FOREIGN PATENTS 968,635 9/1964 Great Britain.

MARVIN A. CHAMPION, Primary Examiner E. I. MCCARTHY, Assistant Examiner