Improvements in Detector Locks and Latches.
Year: 1899

page_text: Date of Application, 29th Mar., 1899-Accepted, 13th May, 1899
COMPLETE SPECIFICATION.
Improvements in Detector Locks and Latches.
I, WILLIAM JAMES BURTON, of Oak Cottage, Sandy Lane, Tettenhall, near
Wolverhampton, Electrical Engineer, do hereby declare the nature of this inven-
tion and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement;-
This invention relates to detector locks and latches, such as door, cupboard,
rim and like locks, padlocks and drop latches, latch bolts and the like for fasten-
ing doors, drawers, gates, windows, and other uses, in which tumblers or their
equivalent are employed in connection with the locking mechanism.
The invention consists in employing in conjunction with the principal tumbler
or tumblers, a secondary tumbler, which prevents the picking of the lock, and
also indicates, on the insertion of the true key for unlocking the previously
fastened lock, whether the tumblers, or any of them, have been over-lifted in an
attempt to surreptiously open the lock by a false key, or to pick the same by
a wire or other means.
Thus, the introduction and turning of a false key or pick transmits such a
motion to the secondary tumbler that the lock mechanism is blocked, disorgan-
ized or placed in an inoperative position, surreptious opening is prevented, and
any subsequent attempts to pick it are frustrated, whilst on the proper key being
introduced and turned in the usual direction for unlocking, it is found that the
mechanism is blocked and this indicates that the lock has been tampered with.
To set the mechanism right again, the key has only to be partially turned the
wrong way whereby the parts are placed in their operative positions and the
secondary tumbler again set into a detecting position, and on then turning the
key in the reverse direction the unlocking can be effected as usual.
Figure 1 of the accompanying drawings represents the interior mechanism of
a detector lock or latch embodying one form of my improvements. This view
shows the three principal tumblers and other parts of the lock and the secondary
tumbler in the positions which they assume when the latch is locked.
Figure 2 is a like view as Figure 1, but showing the parts of the mechanism
blocked, or in the positions they assume after an attempt has been made to sur-
reptiously open the same.
Figure 3 is a view of the lock with the secondary tumbler and the upper
principal tumbler, which latter has a stump or projection engaging with a right
angled gap in the former, removed.
5 Figure 4 is a view of the said upper principal tumbler and its spring separately.
Figure 5 represents the secondary detector tumbler and its spring separately.
Figures 6 and 7 respectively represent like views of the middle and bottom
or inner tumblers and their springs whilst

page_text: Figure 8 represents a separate view of the locking slide.
The same letters of reference indicate corresponding parts in the several
figures of the drawings.
a is the casing of the lock or latch and 6 the bolt with its spring b¹.
locking slide, guided in its traverse by its gaps c¹, ², taking respectively over
c is the
pegs a¹, a³, carried by the casing, with its end e, adapted to be brought against
the back or inner edge 2, of the bolt nose and its lower edge c, having the
notches with which the blade of the key engages. Upon the face of this
slide is the stump d, taking into and through the whole of the gates o, f¹, g',
of the three principal lock tumblers e, f, g. The lower and middle tumblers e
and f, are mounted and swing upon the peg a', with their springs e, f, bearing
against the peg a³, whilst the uppermost or outermost tumbler 9, is mounted
to swing in the opposite direction upon a separate peg at, but with its spring g
also bearing against the peg a³. h is the secondary or detector tumbler, pivoted
at its lower end upon an independent peg h¹, upon which it is adapted to rock,
with its spring h³, bearing against a peg a, whilst cut within the said tumbler
is an angular gap or inverted L-shaped gate i, with which a stump or projec-
tion g', formed or carried upon a tail of the principal tumbler g, is in constant
engagement, either in the vertical part 2, thereof (as shown in Figure 1) when
the parts are in their normal positions and have not been interfered with, or
in the horizontal part 2, (as shown in Figure 2) which is brought coincident with
the said stump 9, when the principal tumblers have been over-lifted by an
attempt to serreptiously open or pick the lock. When the parts are in this latter
position the top tumbler is held or prevented from being lifted by the secondary
tumbler and the mechanism is blocked, inasmuch that the longer parts of the
tumbler gates e, f, g, cannot be brought coincident to provide the necessary
longitudinal clearance for the stump d, of the locking slide to traverse within.
()PERATION.
Assuming the parts are in the locked positions represented in Figure 1, and
that a false key is introduced for the purpose of surreptiously unlocking the
same, the turning of this key over-lifts the upper tumbler to such a height
that its stump g³, is brought coincident with the horizontal part 2, of the angular
gap i, in the secondary or detector tumbler h, whose spring then causes it to
make a downward angular movement in the direction of the arrow Figure 1,
and bring the said part of the gap over or into engagement with the said
stump, thereby blocking the mechanism by securing the said tumbler against
further rocking movement. On the proper key subsequently being introduced
and turned in the usual direction for unlocking the derangement of the parts
is at once detected by the key failing to act, and they are restored to their pro-
per positions by turning back the key in the reverse or wrong direction, when its
blade impinges against the edge of the secondary tumbler, which is forced back
upon its pivot in the direction indicated by the arrow in Figure 2, thus bringing
the vertical or long upright part 2, of the gap in line with, or underneath the
stump g³, of the tumbler g, whose spring causes it to turn upon its pin or pivot
to bring the said stump again into the longer vertical part of the gap and within
which it may make a limited rising and falling movement. The tumbler g, is
thereby freed and the unlocking can now be effected by turning the key in the
ordinary way.
The secondary or detector tumbler may be hung from a pivot instead of swing-
ing upon a pin at its lower end and the gates may be suitably arranged to take
the tail stump of the tumbler, Further the stump which engages the gap of
the detector tumbler may be carried upon any one of the principal tumblers
employed or I may arrange for each principal tumbler to carry such a stump,
with each one engaging in a special or independent gate in the detector.

page_text: The application of my invention to padlocks having no snap fastening action
differs in no essential respect from its application to the detector latch or lock
hereinbefore described, but in applying my invention to padlocks with shackles
fastened by a snap action I proceed as follows, reference being had to Sheet 2
of the drawings, in which
Figure 9 is an elevation showing the interior mechanism of a snap action
detector padlock.
Figure 10 represents the supplementary detector tumbler.
Figure 11 is an ordinary tumbler separately and Figure 12 is the third
tumbler carrying the stump which engages the angular slot in the detector
tumbler.
Figure 13 is another tumbler having a kicker front which acts both for releas-
ing the bolt (shown separately in Figure 14) and throwing the shackle backwards
after being released by the said bolt.
In the arrangement, a is the lock casing with a swinging shackle b, having
a gap 62, adapted to be engaged by the bolt c, which is operated by the key and
works against the back of the said casing. c', c, are the guide gaps in the bolt,
and the spring thereof, whilst d is the stump or the slide taking as before
through the gates o¹, f¹, g', of the principal tumblers e, f and g, the two former
of which swing on a peg a', with their springs e, f, bearing against a suitable
stop whilst the uppermost tumbler g, whose spring is marked g, swings in the
opposite direction upon a peg at. h is the separately mounted detector tumbler,
with spring hand i is the angular gap with which a stump g³, on the tumbler
is in constant engagement and acts in conjunction therewith in exactly the
same way as described in the first arrangement.
It will be observed that the tumbler c, has an arm or extension e³, which comes
underneath the inner end of the shackle, whilst the gate o, thereof in which the
stump d, of the bolt works has an angular extension &, (see Figure 13) so that
when the bolt in being moved backwards by the key for unlocking is brought
coincident with the said gap e', it admits of the said tumbler making an upward
movement by the action of its spring upon it, so that its nose e, strikes against
the shackle (simultaneously with the disengagement of the bolt therefrom) and
throws it back out of the casing.
I wish it to be understood that instead of employing a single detector tumbler
as described, I may employ a series of such tumblers which are moved and act
in unison with one another in the same manner as a series of ordinary tumblers.
Having now particularly described and ascertained the nature of my said in-
vention, and in what manner the same is to be performed, I declare that what
I claim is:-
First-In detector locks and latches, the employment of a gated or gapped
secondary or detector tumbler, turning about a pivot and engaged by a stump
or equivalent part of one of the principal tumblers, and which detector tumbler
is inoperative when the true key is employed but when a false key is used, or the
stump tumbler is over-lifted by the act of picking, it blocks the mechanism.
Secondly-In detector locks and latches, the employment in connection with
the principal lock tumblers, one of which has a stump or equivalent projection,
of a secondary or detector tumbler, turning upon an independent pivot and pro-
vided with an angular or inverted L-shaped gap, with which the tumbler stump
engages, with the parts arranged and operating substantially as and for the
purpose herein described and set forth.
Thirdly: In detector locks and latches of the type referred to in the preceed-
ing claims, mounting the tumbler which carries the stump upon an independent
pivot so that it turns in an opposite direction to the other tumblers, substantially
as described and set forth.
Fourthly-In detector padlocks, the combination with detector mechanism

page_text: as referred to in the first claim of padlock mechanism constructed, arranged
and operating substantially as described and set forth in Figures 9 to 14.
WILLIAM JAMES BURTON.
By Henry Skerrett,
24, Temple Row, Birmingham, Agent for Applicant.
WILLIAM JAMES BURTON.
By Henry Skerrett,
24, Temple Row, Birmingham, Agent for Applicant.