U.S. patent number 3,733,863 [Application Number 05/183,801] was granted by the patent office on 1973-05-22 for lock cylinder mechanism.
Invention is credited to Edwin F. Toepfer.
United States Patent |
3,733,863 |
Toepfer |
May 22, 1973 |
LOCK CYLINDER MECHANISM
Abstract
In an elongated rectangular cavity in a cylindrical body,
elongated tumblers, in a row across the cavity, are lengthwise
slidable parallel to the body axis. Each has longitudinal edges
engaging opposite cavity walls, one edge having one notch therein,
the other several, lengthwise spaced. Across each of said walls a
groove-like recess extends in which the tumblers, when out of
unlocking positions, confine a bar. In their unlocking positions
the tumblers' notches align to define grooves facing into said
recesses and in which the bars are receivable. Balls guided in
radial bores in the body engage the medial portions of the bars to
be held projected by them when the bars are confined in said
recesses.
Inventors: |
Toepfer; Edwin F. (Milwaukee,
WI) |
Family
ID: |
22674343 |
Appl.
No.: |
05/183,801 |
Filed: |
September 27, 1971 |
Current U.S.
Class: |
70/496;
70/411 |
Current CPC
Class: |
E05B
27/086 (20130101); Y10T 70/7893 (20150401); Y10T
70/7621 (20150401) |
Current International
Class: |
E05B
27/08 (20060101); E05B 27/00 (20060101); E05b
019/18 (); E05b 027/08 () |
Field of
Search: |
;70/363,362,411,419,421 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Wolfe; Robert L.
Claims
I claim:
1. A lock cylinder mechanism of the type comprising a hollow
generally cylindrical body, locking means carried by the body for
rotation therewith and for generally radial motion relative thereto
between a retracted position and a projected position, and a
plurality of tumblers in the body normally blocking movement of the
locking means out of its projected position but movable by a proper
key to unlocking positions freeing the locking means for inward
movement to its retracted position, said lock cylinder mechanism
being characterized by:
A. the tumblers being elongated and arranged for lengthwise
movement in directions parallel to the axis of the body, and being
disposed side by side in a row across the body;
B. each tumbler having a longitudinal side edge in which there is a
notch, said notches in the several tumblers all opening to the same
side of the body and being aligned to define a groove transverse to
the body axis when the tumblers are in their unlocking
positions;
C. the locking means comprising
1. a bar in the interior of the body extending across the several
tumblers and confined to motion in opposite directions transversely
to its own length and to the body axis, said bar being at least
partly receivable in said groove when the tumblers are in their
unlocking positions, and the body having a recess opposite said
groove in which the bar is confined when the tumblers are out of
their unlocking positions, and
2. an element confined by the body to substantially radial motion
in opposite directions, said element having an inner part connected
with the medial portion of the bar to move therewith, and an outer
part exposed at the exterior of the body to project therebeyond
when the bar is confined in said recess;
D. each tumbler further having an opposite longitudinal side edge
in which there are a plurality of lengthwise spaced apart notches,
one of said notches in each tumbler being transversely aligned with
one of said notches in each of the other tumblers to define a
second groove, parallel to the first, when the several tumblers are
in their unlocking positions; and
E. a second bar disposed at the opposite side of the tumblers from
the first mentioned bar, said second bar being at least partly
receivable in said second groove when the several tumblers are in
their unlocking positions, and being confined in a second recess in
the body, opposite the first mentioned recess, when the tumblers
are out of their locking positions.
2. The lock cylinder mechanism of claim 1, further characterized
by:
means biasing said second bar radially inwardly relative to the
body at least at times when torque is applied to the body.
3. A lock cylinder mechanism of the type comprising a hollow
generally cylindrical body having a key slot opening to its
interior through a front end thereof, characterized by:
A. a plurality of tumblers in the body,
1. each of said tumblers
a. being elongated in the direction of the body axis,
b. being confined to lengthwise movement in the body, and
c. having a notch in one longitudinal edge thereof,
2. the several tumblers being arranged side-by-side in the body in
a row that extends lengthwise of the key slot and having their said
notches all facing one side of the body and alignable, when the
tumblers are propelled to unlocking positions, to form a groove
that extends transversely to the body axis;
B. a bar in the body extending transversely to the body axis and
across the several tumblers, said bar being at least partway
receivable in said groove that is formed when the tumblers are in
their unlocking positions;
C. the body having a groove-like recess in its interior which opens
to and opposes said groove and in which the bar is confined when
the tumblers are out of their unlocking positions;
D. the body also having a substantially radial bore which opens
from the bottom of said groove-like recess to its exterior, at one
side of it; and
E. a ball in said bore, confined thereby to projecting and
retracting motion in directions substantially radial to the body,
said ball being
1. engageable with the medial part of the bar to be propelled
outwardly by the bar when the latter is moved into said recess in
the body, and
2. exposed at the exterior of the body and projecting radially
outwardly of the body when the bar is confined in said recess.
4. The lock cylinder mechanism of claim 3, further characterized
by:
A. biasing means reacting between the body and each of the tumblers
to bias the tumblers individually forwardly away from their
unlocking positions;
B. said bar having a substantially circular cross section; and
C. said notches in the tumblers being substantially V-shaped, with
their edges oblique to the directions of tumbler motion, so that
they cam the bar out of said groove and into said recess in the
body as the tumblers move out of their unlocking positions.
5. The lock cylinder mechanism of claim 3, further characterized
by:
A. each of the tumblers having an opposite longitudinal edge in
which there are a plurality of other notches at lengthwise spaced
intervals, one of said other notches being in the same relationship
to the first mentioned notch in every tumbler so as to define a
second and oppositely opening groove when the tumblers are in their
unlocking positions;
B. the body having
1. a second groove-like recess which opens to and opposes said
second groove, and
2. a second substantially radial bore opening to its exterior and
to the bottom of said second recess;
C. a second bar in the body, at least partway receivable in said
second groove and otherwise confined in the second recess by the
tumblers; and
D. a second member in said second substantially radial bore having
an inner part engageable with the medial portion of the second bar
and an outer part exposed at the exterior of the body.
6. A lock cylinder mechanism of the type comprising a generally
cylindrical body which is rotatable in a bore in a casing and which
has a cavity in its interior that opens to its front through a key
slot, and a plurality of tumblers that are normally in locking
positions but are propellable to unlocking positions by means of a
proper key inserted into the key slot, said lock cylinder mechanism
being characterized by:
A. the cavity in the body being defined by a pair of opposite walls
that extend lengthwise substantially parallel to the body axis and
are spaced apart transversely of said axis, each of said walls
having an inwardly opening groove-like recess therein that extends
transversely thereacross;
B. each of the tumblers being elongated and having a pair of
opposite longitudinal edges that are respectively slideably engaged
with said opposite walls, the tumblers being arranged in a
side-by-side row across said walls and being movable lengthwise in
directions parallel to the body axis;
C. means biasing each of the tumblers, independently of the others,
forwardly toward its locking position;
D. a pair of bars in the body cavity, one for each of said
recesses, each being of a length to substantially span the row of
tumblers and of a width to be confined in its recess by the
tumblers when the same are in their locking positions;
E. each tumbler having a plurality of lengthwise spaced
substantially V-shaped notches in one of its said longitudinal
edges and a substantially V-shaped notch in its opposite
longitudinal edge, said notches being so arranged that when the
several tumblers are in their unlocking positions one of said
plurality of notches in each tumbler is aligned with one of said
plurality of notches in each of the other tumblers to define a
groove which faces into one of said recesses and in which one of
said bars is partway receivable, and said notches in the other
longitudinal edges of the tumblers are similarly aligned to form a
groove which faces into the other recess and in which the other bar
is partway receivable, the V-shape of said notches being effective
to cam the bars outwardly into their recesses as the tumblers move
out of their unlocking positions; and
F. means biasing each of said bars radially inwardly relative to
the body at least at times when torque is applied to the body, said
means for at least one of the bars comprising a member confined to
radial motion relative to the body between projected and retracted
positions and having
1. an inner portion engaged with the medial portion of said one bar
to move therewith, and
2. an outer portion exposed at the exterior of the body and which,
when said member is in its extended position and the body is in one
position of its rotation, is engageable in a concavity opening to
said bore in the casing, said outer portion being shaped to be
cammed inwardly by rotation of the body to carry said member out of
said concavity.
7. A lock cylinder mechanism of the type comprising a hollow
generally cylindrical body, a plurality of tumblers confined by the
body to motion parallel to one another and in opposite directions,
each of said tumblers having an edge which extends in said
directions of its motion and in which there is a laterally opening
notch, the notches in the several tumblers being aligned to define
a groove when the tumblers are in key propelled unlocking
positions, and a locking element comprising a bar which spans the
tumblers and is at least partway receivable in said groove, said
bar being movable out of said groove in a direction radially of the
body to a projecting position in which the bar is held by the
tumblers when the latter are out of their unlocking positions, said
lock cylinder mechanism being characterized by:
A. each of the tumblers having an opposite edge which extends in
the direction of its motion and in which there are a plurality of
other notches, one of said other notches in each tumbler being
aligned with one of said other notches in each of the other
tumblers to define a second and oppositely opening groove when the
tumblers are in their unlocking positions; and
B. a second locking element comprising another bar which spans the
tumblers and is at least partway receivable in said second groove
and which is movable out of said groove in the opposite direction
radially of the cylinder body.
8. The lock cylinder mechanism of claim 7 wherein one of said
locking elements further comprises:
a member confined to substantially radial motion relative to the
body and having an inner portion engaged with one of said bars to
move therewith and an outer portion which is exposed at the
exterior of the body and which projects beyond the periphery of the
body when said one bar is out of its said groove in the
tumblers.
9. A lock cylinder mechanism comprising:
A. a generally cylindrical body having in its interior a cavity of
substantially rectangular cross-section that occupies a substantial
portion of the length of the body and opens to its exterior through
a key slot at a front end of the body, said body also having a
transversely elongated inwardly opening groove in one axially
extending wall of the cavity and a substantially radial bore
opening to the exterior of the body and to the bottom of said
groove, intermediate its ends;
B. a plurality of flat, elongated tumblers in said cavity, each
having a longitudinal edge which is adjacent to said wall of the
cavity and in which there is a notch, said tumblers being arranged
in the cavity lengthwise parallel to the axis of the body and in
flatwise side-by-side contiguous relationship so that they are
guided by the cavity walls and by one another for lengthwise motion
parallel to the body axis to and from key propelled unlocking
positions in which the notches in the several tumblers are aligned
to define another groove that opens to and is opposite said groove
in the body;
C. means in the body behind the tumblers reacting between the body
and each of the tumblers and engaging the tumbler at its rear end
to bias the tumblers independently forwardly away from their
unlocking positions;
D. a bar in the body wholly receivable in the first mentioned
groove and of a length to span the tumblers so as to be confined
against motion out of said first mentioned groove by the tumblers
when the same are out of their unlocking positions, said bar being
movable transversely to its length to a position in which it is at
least partway received in said other groove; and
E. a member movable in said bore in directions radial to the body,
the last mentioned member having an inner part that has a
connection with the medial portion of said bar for motion therewith
in the last mentioned directions and having an outer portion which
projects beyond the surface of the body when the bar is wholly
received in the first mentioned groove.
10. In combination with a cylindrical lock body having a cavity in
its interior that opens to the front of the body through an
elongated key slot, and a casing having a bore in which the body is
rotatable:
A. a plurality of elongated tumblers,
1. each having a pair of opposite longitudinal edges, in one of
which there is a notch,
2. said tumblers being arranged side-by-side in a row across said
cavity in the direction lengthwise of the key slot, with said edges
of the tumblers engaging opposite flat walls of the cavity to be
guided by the walls of the cavity and one another for lengthwise
motion parallel to the body axis to and from unlocking positions in
which said notches in the several tumblers align to define a groove
that opens to one of said walls of the cavity;
B. a locking element in the body comprising
1. an elongated bar spanning the row of tumblers and at least
partway receivable in said groove when the tumblers are in their
unlocking positions, said bar being confined in a recess in said
one wall of the cavity by the tumblers when they are out of their
unlocking positions, and
2. an element confined to substantially radial motion in the body
and having an inner portion that has a connection with said bar and
an outer portion exposed at the exterior of the body and engageable
in a concavity in the casing when the bar is confined in said
recess;
C. means individually biasing the tumblers forwardly out of their
unlocking positions to normal positions;
D. a key having
1. transversely stepwise arranged shoulders, each engageable with
one of the tumblers upon insertion of the key into the key slot,
for propelling the tumblers rearwardly to their unlocking
positions,
2. opposite substantially flat surfaces engageable with opposite
longitudinal edges of the key slot,
3. a lengthwise extending land projecting from one of said flat
surfaces and receivable in a notch in the body that opens to one of
said edges of the key slot, to confine the key against movement
lengthwise of said edges of the key slot and thus insure that each
of said shoulders will engage with its proper tumbler, said land
having a notch therein spaced from its front end, and
4. forwardly facing abutment surfaces engageable with front surface
portions of the body to define the limit of insertion of the key
thereinto; and
E. pin tumbler means cooperable with the body and the casing to
normally confine the body against rotation, said pin tumbler means
being spaced forwardly in the body from the front ends of the first
designated tumblers when the same are in their normal positions and
being engageable in said notch in the land to be positioned for
release of the body for rotation upon full insertion of the key
into the body, such engagement of the pin tumbler means in said
notch confining the key against withdrawal from the body when the
body is out of predetermined rotational positions.
11. A lock mechanism of the type comprising a hollow body in which
a plurality of tumblers are individually slidable forward and
backward between locking and unlocking positions, and locking means
carried by the body for motion between a locked position in which
the locking means is maintained by any tumbler that is not in its
unlocking position and an unlocked position to which the locking
means can move only when all of the tumblers are in their unlocking
positions, said lock mechanism being characterized by:
A. the body having therein a cavity that is rectangular in
cross-section and which cavity opens to the front of the body
through a single key slot substantially as wide as the larger
cross-sectional dimension of the cavity but shallower than its
smaller cross-sectional dimension to define at least one rearwardly
facing shoulder at the front of the cavity that extends across its
said larger dimension;
B. the tumblers
1. being elongated and each having opposite flat sides,
2. being arranged side-by-side in a row across the cavity in the
body, between opposite flat side surfaces of the body that define
said cavity, and with said flat sides of the tumblers flatwise
contiguous to one another and to said surfaces, so that the
tumblers are guided for lengthwise sliding motion by their
engagement with one another and said surfaces, and
3. each tumbler having its front end engageable with said shoulder
to define the locking position of the tumbler;
C. each tumbler having a longitudinal edge in which there is a
notch, said notches in the several tumblers all opening in the same
direction to a wall of the body that extends between said surfaces,
and said notches being alignable, upon lengthwise sliding of the
several tumblers to their unlocking positions, to define a groove
that extends transversely to the lengths of the tumblers;
D. the locking means comprising
1. a bar in the interior of the body extending across the several
tumblers and confined to motion in opposite directions transversely
to its own length and to the lengths of the tumblers, said bar
being at least partway receivable in said groove when the tumblers
are in their unlocking positions, and the body having a recess in
its said wall, opening to said cavity, in which the bar is confined
when the tumblers are out of their unlocking positions, and
2. an element confined to motion in substantially said opposite
directions of motion of the bar, said element having an inner part
connected with the bar to move therewith and which extends through
a hole in said wall of the body, and having an outer part that
projects beyond the body when the bar is confined in said recess;
and
E. spring means in the body, behind the tumblers, reacting against
the body, and engaging each tumbler at its rear end, biasing each
tumbler forwardly independently of the others towards its defined
locking position.
12. The lock mechanism of claim 11, further characterized by:
F. said body having a plurality of wells in its rear portion, one
for each tumbler, each opening forwardly into the cavity at the
rear thereof;
G. a pin-like rearward projection on each tumbler; and
H. said spring means comprising a plurality of coiled expansion
springs, one for each tumbler, each of said springs having a rear
end portion received in one of said wells and a front end portion
piloted on the pin-like projection on its tumbler.
13. The lock mechanism of claim 12, further characterized by:
I. said body having a bore concentric with each of said wells and
of smaller diameter than its well, opening to the well and to the
rear end of the body; and
J. each of said pin-like projections being long enough to extend a
substantial distance into its well, within its spring, when the
tumbler is in its locking position, and being receivable in the
bore concentric with the well when the tumbler is in its unlocking
position.
Description
This invention relates to pick resistant lock cylinder mechanisms
and is more particularly concerned with a lock cylinder mechanism
that is especially well adapted for installations in which hard and
rough usage and other circumstances unfavorable to the security and
durability of a lock are likely to be encountered.
Heretofore the designers and manufactures of cylinder locks have
placed great importance upon the attainment of small size,
particularly of the key slot, on the theory that the picking of a
lock is difficult if its key aperture leaves little space for the
probing and manipulating required in the picking operation. But
miniaturization of the lock cylinder mechanism and its parts
entails the need for precision in manufacture, with its attendant
expense, and correspondingly shortens the useful life of the
mechanism by increasing its vulnerability to the effects of wear
and the elements. Furthermore, other things being equal, a small
lock mechanism is more easily forced than a large one. There is
thus a point where miniaturization becomes imcompatible with
security, rather than promoting it.
There are many situations, moreover, in which security requires the
use of a large and sturdy lock mechanism having relatively massive
parts, including a stout key that will withstand all sorts of
abuse. In a lock cylinder mechanism intended to meet such
conditions, resistance to picking obviously cannot be achieved by
miniaturization, but, instead, the arrangement of the lock
mechanism must be inherently such as to render it pick
resistant.
With the foregoing considerations in mind, it is a general object
of this invention to provide a lock cylinder mechanism that is pick
resistant by virtue of the shape, arrangement and cooperation of
its parts, and which can therefore be made in very large sizes
without any sacrifice of its security.
It is also an object of this invention to provide an inherently
pick resistant lock cylinder mechanism having relatively few and
simple parts that do not have to be manufactured to close
tolerances in order to assure security and dependable operation,
and which is thus nicely adaptable to small locks as well as to
large ones, with cost advantages in locks of all sizes.
Another object of this invention is to provide a lock cylinder
mechanism that can be so constructed as to be cooperable with a
large and sturdy key, such as is generally favored for prison
locks, but which is nevertheless very pick resistant and not
readily disabled by foreign matter that enters, or is inserted
into, its key aperture.
It is also an object of this invention to provide a lock cylinder
mechanism in which the key does not have sliding engagement with
the tumblers during its insertion and withdrawal, so that the
tumblers can be made very hard, to insure high strength and
security, without entailing the risk that the bitting on the key
will be worn down or deformed by repeated use.
Another and more specific object of this invention is to provide a
lock cylinder mechanism from which the key can be withdrawn in any
position of cylinder rotation.
A further object of this invention is to provide a lock cylinder
mechanism which is particularly well suited to applications in
which high torque must be exerted through the cylinder mechanism
and its key, the mechanism being well adapted for use with a sturdy
key, as explained above, and arranged for insertion of the key
concentrically to the cylinder body.
It is also a special object of this invention to provide a lock
cylinder mechanism that is cooperable with a key having its bitting
provided by movable fingers which are adapted to occupy normal
retracted positions, wherein they do not reveal the coding of the
lock, but which are readily extensible to operative positions by a
person having knowledge of the combination for the lock.
With these observations and objectives in mind, the manner in which
the invention achieves its purpose will be appreciated from the
following description and the accompanying drawings, which
exemplify the invention, it being understood that such changes may
be made in the specific apparatus disclosed herein as come within
the scope of the appended claims.
The accompanying drawings illustrate several complete examples of
embodiments of the invention constructed according to the best
modes so far devised for the practical application of the
principles thereof, and in which:
FIG. 1 is a perspective view of a lock cylinder mechanism embodying
the principles of this invention, shown together with a key for
actuating the same;
FIG. 2 is a longitudinal sectional view of the lock cylinder
mechanism shown in FIG. 1;
FIG. 3 is a view similar to FIG. 2 but showing the mechanism
actuated by its key to its unlocked condition;
FIG. 4 is a longitudinal sectional view taken on the plane of the
line 4--4 in FIG. 2;
FIG. 5 is a view in longitudinal sectional view taken on the plane
of the line 5--5 in FIG. 3;
FIG. 6 is a view in cross section taken on the plane of the line
6--6 in FIG. 4;
FIG. 7 is a view in cross section taken on the plane of the line
7--7 in FIG. 5;
FIG. 8 is a view in elevation, with portions broken away, to show
the notches along one longitudinal edge of each tumbler, the lock
cylinder mechanism being shown in a casing or housing in which it
is rotatable;
FIG. 9 is a view in cross section corresponding generally to FIGS.
6 and 7, but showing the cylinder body in a condition that might
occur during an attempt to pick it, rotated slightly out of its
locked condition but still locked against free rotation; and FIG. 9
further differs from FIGS. 6 and 7 in illustrating a modified form
of the locking elements;
FIG. 9a is a fragmentary sectional view generally like FIG. 9, but
illustrating a further modified form of locking element;
FIG. 10 is a disassembled perspective view of the principal
components of the lock;
FIG. 11 is a longitudinal sectional view illustrating a modified
embodiment of the lock of this invention;
FIG. 12 is a sectional view taken on the plane of the line 12--12
in FIG. 11;
FIG. 13 is a plan view of a modified form of key for the lock of
this invention;
FIG. 14 is a sectional view taken on the plane of the line 14--14
in FIG. 13;
FIG. 15 is a fragmentary view in longitudinal section of a further
modified embodiment of the lock mechanism of this invention, shown
with its key inserted and the mechanism in unlocked condition;
and
FIG. 16 is a sectional view taken on the plane of the line 16--16
in FIG. 15.
Referring now to the accompanying drawings, the numeral 2
designates generally a hollow generally cylindrical body for a lock
cylinder mechanism embodying the principles of this invention,
adapted to be rotatably mounted in a bore 3 in a housing or casing
4. The body has in its interior a cavity 5 in which there are a
plurality of tumblers 6, and it also carries a pair of locking
element 7, 7'. The tumblers 6 are actuatable from normal locking
positions to unlocking positions by insertion of a key 8 into the
interior of the body through a key slot 9 in its front.
When the tumblers are in their locking positions, they confine each
locking element 7, 7' to a projecting position in which a part of
the locking element extends radially beyond the circumferential
surface of the body to be engaged in a pocket or concavity 10, 10'
in the housing that opens to the bore 3 therein. Such engagement of
the locking elements in the concavities of course prevents rotation
of the body in the bore. In their unlocking positions, the tumblers
release the locking elements for movement radially inwardly
relative to the body, so that torque applied to the body by means
of the key can cam the locking elements out of the concavities 10,
10' and to retracted positions in which the locking elements do not
interfere with rotation of the body.
The body 2 can be comprised of a pair of generally similar
complementary units 12, 12', which can be either machined to shape
or made as investment castings of stainless steel or other hard
metal. These body units are, in the main, formed as the halves of a
cylinder divided on a plane lying along its axis. Each has a large
mortise 13 of rectangular cross section extending along most of its
length to provide one-half of the cavity 5 in the body; hence the
cavity is of rectangular or substantially square cross section. At
its front end the body unit 12 has an integral disc-like projection
14 which overlies the front end of the other body unit 12' and in
which the key slot 9 is formed. At its rear the body unit 12' has a
generally similar projection 15 which overlies the rear end of the
body unit 12. The body units are secured together, as by means of
axially extending studs 16 on each, press fitted into the
projection 14 or 15 on the other unit.
The two body units cooperate to define a row of axially extending
tumbler guide holes 17 at the rear of the body, each having its
axis on the parting plane of the body units. The tumbler guide
holes (the purpose of which is described hereinafter) extend
through a tongue 21 that projects rearwardly from the body to
provide for connection of the body with a latch bolt (not shown) or
the like that is to be secured by the lock mechanism. The tongue 21
can have rectangular cross section and is shown as symmetrical to
the body axis and formed integrally with the projection 15 on the
body unit 12'.
Each of the opposite cavity walls 18 and 18' that lies wholly in
one of the body units has in it a groove-like recess 19, 19' that
extends transversely across the wall, intermediate its ends. Each
body unit also has a radial bore 20 that opens to the bottom of its
recess 19 or 19' and to the outer circumferential surface of the
body. Each recess and its bore cooperate with one of the locking
elements 7, 7' as explained hereinafter.
The tumblers 6 are flat and plate-like. They are substantially
elongated and are generally rectangular in shape, although one
lengthwise extending edge 22 of each tumbler has a notch 23 therein
and the opposite longitudinal edge 24 preferably has a plurality of
generally similar notches 25 at uniformly spaced intervals along
its length. The tumblers are arranged in the body cavity lengthwise
parallel to the axis of the cylindrical body and in flatwise
side-by-side relationship, in a row across the cavity walls 18 and
18'. They are of such width as to have their longitudinal edges 22
and 24 in sliding engagement with the cavity walls 18 and 18'
respectively. The outermost tumblers of the row are in flatwise
sliding engagement with the other two cavity walls 26 and 26'.
Thus it is a feature of the lock cylinder mechanism of this
invention that the tumblers are confined by the cavity walls and
one another to lengthwise motion in the body in directions parallel
to its axis. The key 8 propels them rearwardly from normal
positions at the front of the cavity to unlocking positions
described hereinafter. The front edges 27 of the tumblers are
normal to their longitudinal edges 22 and 24 and to the axis of the
body, for abutting engagement with shoulders 34 on the key that
face into the body and comprise its bitting, said shoulders being
in stepped relation to one another across the width of the key
shank. It will be observed that there is no relative sliding
between the tumblers and the key, hence the tumblers can be very
hard without danger that they will wear down the key bitting.
Because the tumblers slide upon one another, they tend to be self
cleaning, that is, any foreign matter that gets between them tends
to be worked forward by their sliding action, for expulsion through
the key slot 9.
Each tumbler has a pin-like rearward extension 28 that is parallel
to the body axis and is slidingly received in one of the tumbler
guide holes 17 in the rear of the body. These extensions, in
cooperation with the guide holes, further steady and guide the
tumblers in their back and forth motion, but the main function of
each extension is to serve as a pilot for a coiled compression
spring 29 which surrounds it and which reacts between its tumbler
proper and the rear wall of the cavity to bias the tumbler
forwardly to its normal position.
The unlocking position of each tumbler is established by inserting
the key all the way into the key slot until coplanar stop abutments
35 on the key, at each side of its stepped shank, engage the front
face of the body adjacent to the ends of the key slot. When the
tumblers are in their unlocking positions, the notch 23 in each is
directly opposite the groove-like recess 19 in its adjacent cavity
wall, so that the aligned notches 23 define a groove 30 which opens
into said recess. At the same time one of the several notches 25 in
the opposite edge of each tumbler is aligned with a notch 25 in
each of the other tumblers, and such aligned notches define another
groove 31 which opens into the opposite recess 19'.
Each locking element 7, 7' comprises a bar 32, 32' which can be in
the form of a pin having a length to span the row of tumblers and a
diameter to be wholly receivable in one of the groove-like recesses
in the body. When the tumblers are out of their unlocking positions
they confine the bar 32 in the recess 19 and the bar 32' in the
recess 19'. When the tumblers are in their unlocking positions, the
bars 32 and 32' are of course free to move radially inwardly
relative to the body to be partway receivable in the grooves 30 and
31, respectively in the row of tumblers.
Each locking element 7,7' also comprises another part 33, 33',
shown as a ball in certain of the Figures and which is slideable in
directions radial to the body in the bore 20. An inner portion of
the part 33, 33' is engaged with the medial part of the bar to move
therewith; an outer portion of said part is exposed at the exterior
of the body.
When the tumblers are out of their unlocking positions and the bars
32, 32' are confined in the recesses 19, 19' in the body, each bar
holds its associated ball 33, 33' in a projected position in which
the outer portion of the ball extends beyond the body circumference
to be receivable in one of the pockets or concavities 10, 10' in
the casing or housing 4. Such engagement of the balls 33 in the
concavities 10, 10' of course prevents rotation of the body in the
casing and defines the locked position of the body. When the
tumblers are key propelled to their unlocking positions, freeing
the bars 32, 32' for radially inwardly motion relative to the body,
the balls can be cammed inwardly by the ends of the concavities 10,
10' as the body is turned.
Suitable means (not shown) can be provided for defining the limits
of rotation of the body to its locked and unlocked position.
However, it should be noted that with the herein illustrated
mechanism the key 8 can be withdrawn in any position of rotation of
the body, although those skilled in the art will appreciate that
there would be no difficulty in providing means for holding the key
captive whenever the body is not in one or more predetermined
positions of its rotation.
If an attempt is made to pick the lock of this invention, the
notches 25 in the edges 24 of the several tumblers can align with
one another in numerous combinations of tumbler positions, in each
of which the bar 32' is freed for motion out of its recess 19' and
into the groove defined by the notches thus aligned. But of course
there is only one combination of tumbler positions in which the
notches 23 in the opposite edges of the tumblers are also aligned
with one another and the recess 19; hence in all but one
combination of tumbler positions the freeing of the bar 32'
provides a false clue to a person attempting to pick the lock. He
is led to think that he has discovered the combination, whereas in
fact the body cannot be rotated in its casing unless both balls 33
and 33' can retract. To increase the versimilitude of the false
clues thus provided, the pocket of concavity 10 that cooperates
with the ball 33 can be circumferentially extended to a slight
extent, to permit a few degrees of rotation of the cylinder body
upon retraction of the other ball 33'. The multiplicity of false
clues afforded by the lock mechanism of this invention makes it
necessary to try a very large of tumbler position combinations in a
systematic attempt to pick the lock, and therefore the picking
operation is a tedious and discouraging one. Moreover, in any
attempt to pick a lock it is necessary that a light torque force be
applied to the cylinder all during the operation, so that arrival
of the tumblers at their unlocking positions can be detected. With
the lock of this invention, each positioning of the tumblers to
align a group of the false clue notches 25 permits the cylinder to
rotate a few degrees out of its locked position and then causes all
of the tumblers to be held against any axial motion by reason of
the engagement of the bar 32' into the aligned notches 25. To
resume the picking operation, it is necessary to relieve the torque
on the cylinder, whereupon all tumblers move back to their locking
positions so that the whole picking operation must be resumed from
the beginning.
To facilitate mass production, the notches 25 in the edge 24 of
each tumbler are spaced at regular intervals along said edge, the
pattern of said notches is identical from tumbler to tumbler, and
in each tumbler the single notch 23 in the other longitudinal edge
is located directly opposite one of the several notches 25. Thus
mass production needs only as many different tumblers as there are
notches 25 in the edge 24 of each, and the coding of each lock and
its key is determined by the combination of such different tumblers
used therein, in accordance with well-known practice in the lock
art.
If desired, the locking element 7' can be omitted, and the
longitudinal edge 24 on each tumbler can then be straight and
unnotched. In that case false clues would not be given to a person
attempting to pick the lock, but picking would still be attended by
the usual difficulties encountered in trying to decode a
conventional side bar lock, wherein at least a substantial minority
of the tumblers must be brought to their unlocking positions before
a readily discernible response of the lock mechanism can be
detected. In this connection it should be noted that each ball 33,
33', in engaging its bar 32, 32' at the medial portion thereof,
applies its inward biasing force to the bar in a manner that
encourages the bar to move inward with a lateral translatory motion
and discourages tilting of the bar.
With bars that are round in cross section, as shown, and with
V-shaped notches in the tumblers to define the grooves 30 and 31 in
which the bars are received, lengthwise motion of the tumblers out
of their unlocking positions moves the bars into their recesses 19
and 19' as the oblique edges of the notches cam the bars outwardly.
Hence no special provision need be made for biasing the locking
elements to their locking positions. Furthermore, with V-shaped
notches cooperating with a round bar, the tumblers need not be made
with unduly high precision nor to extremely close tolerances.
However, V-shaped notches have the disadvantage that only a
relatively small number of them can be accommodated along a given
length of tumbler. For a compact lock capable of a larger number of
tumbler combinations, the notches 23 and 25 can be made
substantially square, as illustrated in FIG. 11, although in that
event it may be necessary to go to somewhat higher standards of
precision in the manufacture of the cylinder mechanism. Moreover,
with square cut notches the locking elements 7, 7' will not be
cammed outwardly to their locking positions by lengthwise motion of
the tumblers, and separate biasing means must be provided for the
bars 32 and 32'.
As shown in FIG. 11 and 12, such biasing means can comprise a pair
of compression springs 37, each reacting between the adjacent ends
of the two bars 32 and 32' to urge the bars away from one another.
These springs are housed at opposite sides of the row of tumblers,
in recesses 38 in the cavity walls 26 and 26'. The recesses 38
extend into the ends of the bar receiving recesses 19, 19', and
each bar is of course long enough to have its opposite end portions
project beyond the row of tumblers and into the end portions of the
spring recesses 38 to be engaged by the ends of the springs 37.
When the locking elements 7 and 7' are in the form of balls, as
shown for example in FIGS. 6 and 7, they make only point contact
with the respective bars 32 and 32', and consequently the balls and
bars are subjected to high localized forces and possible damage by
attempted forcing or other abuse of the lock. As indicated in FIG.
9, this can be avoided to some extent by forming each of the
locking elements 7, 7' with a cylindrical inner end portion 7a that
makes a line contact with the cooperating bar, and with a
hemispherical outer end portion 7b that cooperates with the
concavity or pocket 10, 10' in the same manner as the ball.
Alternatively, as indicated in FIG. 9a, the locking elements 7 and
7' can comprise an inner cup-shaped member 7c, the bottom of which
makes line contact with the adjacent bar, a ball 7d that is
receivable in the cup-shaped member, and a small compression spring
7e that is also received in the cup-shaped member and reacts
between it and the ball 7d to bias the latter outwardly. In this
case the cup-shaped member 7c can have sufficient height to be
partway receivable in the adjacent concavity in the locking
condition of the mechanism, providing a shear plane comparable to
that in a conventional pin tumbler lock and thus providing further
security against forcing. Note that the last described embodiment
of the locking element has the further advantage that the spring
urged ball 7d cooperates with its concavity to afford a detent
which defines the locking position of the cylinder.
The modified forms of locking elements 7 and 7' just described,
which make line contact with their cooperating bars 32, 32', have
the further advantage that they prevent said bars from tilting when
the several tumblers are between their respective locked and
unlocked positions, and particularly when notches 23 or 25 on end
tumblers are aligned with the bars. Hence those modified locking
elements further tend to frustrate any attempt to pick the lock, by
eliminating clues that might be afforded by such tilting of the
bars.
An important consequence of the tumbler arrangement in a lock
cylinder mechanism embodying the principles of the present
invention is that it lends itself to cooperation with a novel type
of key 8', illustrated in FIGS. 13 and 14. Instead of having fixed
bitting that can be more or less easily copied by unauthorized
persons, the key here shown has a number of elongated lengthwise
slidable fingers 40, each having a width and thickness equal to
those of a tumbler. The fingers are slidable back and forth in a
shell or housing 41 that comprises the shank of the key, so that
they can be retracted to inoperative positions wholly within the
shell or can be projected to operative positions in which they
extend forwardly from the shell.
Each of the fingers can be releasably secured in any of a number of
projected positions, corresponding to the coding of the tumblers,
as by means of a button-like latch 43 that projects from the finger
through a slot 44 in one wall 42 of the shell. Each slot 44 extends
lengthwise along its finger and has widened bays 45 that are spaced
along its length at intervals equal to the distances between the
notches 25 in the tumblers. Each button-like latch has a large
diameter inner portion 46 that is wider than the slot 44 but is
receivable in any one of the bays 45, a smaller diameter outer
portion 47 that is receivable in the slot 44 all along its length,
and a large diameter head 48 that overlies the slotted wall 42 of
the shell. A leaf spring 50 is confined between each finger and the
opposite wall 51 of the shell. It biases the finger laterally
toward the slotted shell wall 42 and tends to maintain the finger
in a position in which the large diameter inner portion 46 of its
button-like latch is engaged in one of the bays 45. However, each
finger can be readily shifted lengthwise, to engage its latch 43 in
a different selected bay, by depressing the head 48 of the latch to
align its narrow outer portion 47 with the slot 44.
An authorized person intending to use the key will have knowledge
of the combination of positions to which the fingers must be set,
which combination corresponds to the coding of the tumblers in the
lock mechanism that the key is intended to actuate. Normally all of
the fingers will be in their retracted positions, in which the key
is most compact and in which the lock cannot be decoded. To
facilitate setting up the key for use, the several slots 44, and
the bays 45 in said slots, can be identified by suitable indicia on
the shell.
Since the lock of this invention can be made in large sizes without
sacrifice of its resistance to picking, it lends itself to
cooperation with a key of the kind just described, inasmuch as the
key can be made correspondingly large and can thus accommodate
various springs, latches and the like.
As will be apparent from FIG. 1, the key must be inserted into the
key slot in the proper position lengthwise along the key slot, to
insure that each of the shoulders 34 on the key will engage its
proper tumbler. Proper location of the key during its insertion can
be facilitated by providing the key with a lengthwise extending
land 53 that projects up from one of its opposite flat faces and is
receivable in a notch 54 in one of the longitudinal edges of the
key slot, all as illustrated in FIG. 16.
If desired, the land 53 can be made to perform the additional
function of captivating the key to prevent its withdrawal from the
body except in predetermined rotational positions thereof. To this
end, as illustrated in FIG. 15, the body is provided with a
generally conventional pin tumbler means 55, located forwardly of
the front ends of the tumblers 6 when they are in their normal
positions. The tumbler means comprises a tumbler 57 in a radial
bore in the body that opens to the cavity therein, a driver 58 in a
radial bore 59 in the casing 4 opening to the bore 3 therein in
which the body rotates, and a small spring 60, also confined in the
radial bore 59. In the locked position of rotation of the body, its
tumbler bore registers with the driver bore 59 in the casing, and
the driver projects partway into the tumbler bore. Note that the
tumbler bore is actually defined by a radially inner bore 62 and a
counterbore 63, and that the tumbler has an enlarged head 64 which
bottoms on the junction of the bore and the counterbore to define
its normal position. The spring 60, which reacts between the driver
and a spring retainer 65 on the casing, urges the driver radially
inwardly and through it tends to maintain the tumbler in its normal
position.
When the key is partway inserted into the body, the land 53 thereon
propels the tumbler 57 partway into the driver bore, but when the
key is fully inserted, as shown in FIG. 15, the tumbler seats in a
notch 67 in the land 53 to establish the contacting surfaces of the
tumbler and the driver on the so-called shear plane of the lock. It
will be seen that this arrangement is the generally conventional
one for pin tumbler locks, except that the bitting for the pin
tumbler is on the land 53 instead of being on the edge of the key
as is usual.
Upon rotation of the cylindrical body, the tumbler and driver are
confined in their key established positions by the conventional
surfaces of the bore 3 and the body 2, respectively, and
consequently the key cannot be withdrawn until the body is rotated
back to its normal locking position. Such captivation of the key by
a pin tumbler is again generally conventional in pin tumbler
locks.
It will be apparent that the presence of the pin tumbler means 55
tends to further complicate the picking of the lock.
From the foregoing description taken with the accompanying drawings
it will be apparent that this invention provides a high security
lock cylinder mechanism which can be made at relatively low cost
and which is inherently resistant to picking and therefore lends
itself well to installations where a large, sturdy lock is
required.
Those skilled in the art will appreciate that the invention can be
embodied in forms other than as herein disclosed for purposes of
illustration.
The invention is defined by the following claims.
* * * * *