Note: Descriptions are shown in the official language in which they were submitted.
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The present invention relates to a catch or look.
According to the present invention there is provided a lock
comprising a casing, a rotatable cam mounted to the casing and
means of the cam for accepting a key. A latch is provided which
comprise at least one latch arm including a hasp engaging
latching means. the latch being in cooperable relationship with
the cam. A hasp is provided with which each latching means is
engageable for locking. The arrangement is such that on inser-
tion of the key into the lock, the cam may be rotated to dis-
engage the latch from the hasp. Two abutments form stop means
for determining releasing and locking positions of the cam. The
key is insertable or removable wllen the cam is in the locking
position, wherein a groove and follower cooperatively couple the
casing and the cam. The groove has a first and second portion,
the first portion having a ramp with a raised end forming one of
the abutments at an end of the second portion. Another of the
abutments is formed at another and of the second portion. The
follower engages in the groove and acts with the abutments to
limit the movement of the cam relative to the casing and acts
with the ramp to limit the movement in a direction from the first
portion to the second portion and not in reverse of the direc-
tion. An end of the first portion remote from the second portion
defines a first supplementary releasing position of the cam, the
key being insertable or removable from the lock at the first
supplementary releasing position.
The arrangement provides a very simple lock which is
economical to mould and can be operated by a simple key which is
preferably double bitted.
The advantage of the above arrangement is that the catch or
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lock can be in a semi-permanently disengaged condition when the
cam follower is in the first portion and is inoperative. This is
particularly useful for a dispenser for paper towels and the like
which some operators prefer to be unlocked. rn this case the
cover is retained by suitable non-locking means such as a stud
springing into a hole. If the dispenser operator requires the
cover to be lockable. the cam follower is turned by the key to
the second groove portion where the lock or catch is fully
operative.
The cam may be substantially triangular in shape and two
latches are provided. the cam acting between the latches so that
on rota-tion of the cam both latches are disengaged from the hasp.
A specific embodiment of the invention will now be described
by way of example with reference to the accompanying drawings in
which:
Figure 1 is a plan view of a catch or lock according to the
invention with the cam in a groove first portion and unlatched,
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Figure 2 is a cross section of part of Fig. 1
taken on AA with a key for operating the lock,
Figure 3 is a plan view of the catch or lock
of jig. 1 showing the casing only,
Figure 4 is a cross-section of the casing of
Fig. 3 taken on BB showing particularly the groove,
Figure 5 is a plan view of the catch or lock ox
Fig. 1 with the cam in a groove second portion and latched,
and,
Figure 6 is a plan vicw of the ca-tch or lock of
Fig. 1 with the cam in the yroove second portion and
unlatched .
In Figure 1 of the drawings a catch or lock is
shown formed from four main parts, namely a casing 1, a
double latch mernber 2, a cam 3 and a hasp 4.
The casing as shown in Figures 3 and 4 comprises
a stud 5 engageable with a hole in the latch member 2, and
a protrusion 6 with a tapped hole 7 to receive a screw 8,
the screw 8 and stud 5 firmly locating the latch member's
rear portion 9 on the casing. The casing also has a key
aperture 12 surrounded by a bearing protrusion 13 for engaging
with a recess 14 in the cam 3. also the casing has a groove
15 which has 2 ramped first portion 16 and a second por-tion
17. The groove receives a follower 18 projecting from the
bottom of the cam and the follower can rotate anti-clockwise
over the ramp in the groove from position X in Fig. 1 and into
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the second portion 17 but cannot rotate clockwise from
second portion 17 to first portion 16 because of the ramp.
The double latch rnember 2 as shown in Figure 5
comprises a rear portion 9 firmly located to the casing as
described above, resilient portions 20 extending from the
fixed rear portion 9, cam engaging portions 21 which over-
lie a circular flange 22 of the cam so as to hold the cam
onto the casing, and latch portions 24 terminating in hooks
25 which engage with barbs 26 of the hasp.
The cam 3 is formed with a cc-ntral triangular
portion 30 in which is a recess 32 for a key 33 having a
double bit 34. The portion 30 also has a hole 35 to receive
the stem end 36 of the key. The cam also has follower 18,
a retaining flange 22 and recess 14 as already described.
The hasp is formed as aescribed with two barbs
26 extending either side o a stem 38 (see Fig. 6).
In order to ensure that when the key is inserted
in the cam that the latch portions 24 are not forced out
of engagement with the hasp a bridge 40 secured to the
20 casing may be provided (see Figs. 4 and 5).
A plug (not shown) can be fitted in casing key
aperture 12 if -the lock is not to be opera-tive.
The lock is normally supplied with the plug in
aperture 12 and the lock is in a non-locking state as shown
25 in Fig. 1 with the follower 18 in position X. If it is
required to use the lock the plug is removed, the key inserted
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in cam 3 into aperture 32 and the cam rotated so that
the follower snaps over the ramp into second groove
portion 17 on reaching position Z as shown in Fig. 5
the key can be removed and the lock is latchedO To
unlatch the lock the key is reinserted and the cam moved
to position Y as shown in Figo 6. In this position the
key cannot be removed because recess 32 is misaligned
with aperture 12. When the cam is in position Z as
shown in jig. 5 the hasp 4 can be sprung in locking
engagement with latch member 20
I-t will be obvious from the fact that the cam 3
has an equilateral triangular shape that s-tarting
a-t posi-tion X (as in Figo 1) where the key is
insertable and the latch member is open, the cam is
movable after key insertion through 120 to position Y
(as in Figo 6) where the latch member is again openO
; Thence -the cam moves through a further 60 to position Z
(as in Fig 5) where the key is removable and the latch
member is closed. The total cam movement being 180
(the arcuate leng-th of the groove being slightly greater
to allow for cam follower thickness andthe first portion
16 of the groove 15 is about 120 and the second portion
17 about 60 with an allowance for cam follower thickness.
A particular use for the lock described above
as in a dispenser for paper towels and such like where
some operators prefer the dispenser to be permanently
unlocked whilst some operators prefer a lockable dispenser.
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' It will be appreciated that the casing l can form
part O:e an article to be locked that is being integral
with the object being locked or else the casing can be a
plate or the like which is attached by attachment means
such as screws -to the object being locked,
It will also be appreciated that whils-t the follower
is described as being on the cam and the groove in the
casing, the reverse is within the scope of the invention
and would be equally effectiveO Also the groove can be
circular with the second portion 120 and -the first
portion 240 in arcuate lengthO
