Augmented key and cylinder lock

DETAILED DESCRIPTION The present device is in one environment incorporated in a lock 6 in which a driver bar 7 rotates about an axis 8 to actuate the lock.
An early version of a lock of this kind is shown in Walter R.
Schlage U.
S.
Pat.
No.
2,293,856 of Aug.
25, 1942.
The lock driver bar is received in one end of a plug 9 rotatable about the axis 8 and within a housing 11.
An extension 12 of the housing has a number of radial bores 13 therein containing springs 14 and upper tumbler pins 16 in the customary way.
These bores are likewise, in one position of the plug 9, in alignment with comparable bores 17 in the plug and contain lower pins 18.
When properly positioned, the lower pins are designed to cooperate with the upper pins to establish a shear plane so that the plug 9 can be rotated in the housing.
Otherwise, some of the pins bridge the shear line and prevent plug rotation.
The plug at one end is axially restrained by an adjustable and locked collar 20 and at the other end is restrained by an integral, extending flange 21.
One planar side 22 of the flange abuts the planar end face 23 of the housing, and the other side of the flange is finished to afford a generally planar surface 24 normal to the axis 8.
There is a keyway 25 formed in the plug in the customary way, the keyway extending through the front flange 21 and leaving a notch 26 therein located where the keyway 25 extends axially and radially through the extended flange 21.
This is customary in plug manufacture.
In the usual lock, as shown in FIG.
6, the plug keyway 25 is adapted to receive a standard key 31 having a bow 32 and an axially extending shank 33.
One longitudinal edge 35 of the key shank is provided with serrations 34 interacting directly with the lower pins 18 when the key is in position so as to establish the pin shear line, above mentioned.
The other edge 36 of the key is generally rectilinear and is designed to bear against the inside surface of the bore.
In its usual configuration, the key 31 has a first shoulder 37 designed substantially to abut against the face 24 when in operating position