Note: Descriptions are shown in the official language in which they were submitted.
2008791
A LATCHING MECHANISM
The present invention relates to a latching
mechanism. The mechanism is intended particularly,
but not exclusively for a cash box.
Known latching mechanisms of this type are
usually made of metal, have many parts and are
therefore difficult and expensive to produce and
maintain and are noisy in operation.
According to the present invention, there is
provided a mechanism comprising actuator means and
a latch, in which the latch is disposed to contact
a catch to perform a latched action, characterised
in that the actuator means is disposed for
movement between a first position in which the
latch is held in an operative latched position and
a second position in which the latch is released
to enable it to release the catch under the action
of its own inherent resilience.
ln a preferred embodiment of the invention,
the latch is pivotally mounted and is moulded from
resilient synthetic plastics material such as
acetal. The actuator means comprises a low voltage
solenoid which coacts with a rocker member. The
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rocker member is pivotally mounted for movement
between the first and second positions. The
rocker member coacts with the latch and the ~ -
surfaces of contact are formed to facilitate this.
The latch comprises a resilient extension which
coacts with a projection formed on the housing for
the latch. This resilient extension effectively
acts to store energy which may be released to
pivot the latch to an unlatched position.
ln order that the invention may be more
clearly understood, one embodiment thereof will
,
now be described, by way of example, with
reference to the accompanying drawings, in which:-
Figure 1 shows a section through a latchingmechanism according to the invention with the
mechanism in the locked position,
Figure 2 shows a section through the
mechanism of Figure 1 but with the mechanism in
the unlocked position, and
Figure 3 shows a cross-section through a cash
box incorporating a modified form of the mechanism
shown in Figures 1 and 2.
;:
Referring to Figure 1, the mechanism
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2008791 :~:
comprises a low voltage solenoid 1 incorporating a
movable actuator rod 2. A head 3 is fixed to the
free end of the rod 2 and a compression spring 4 ~;
is constrained to act between that head 3 and the
housing 5 of the solenoid. The head end of the
solenoid coacts within an intermediate rocker 6.
The rocker 6 is mounted for pivotal movement about
a pivot 7 disposed on the support structure for
the mechanism. Where the latching mechanism is a
cash box, this support structure may be the box
itself or connected to the box.
A latch member 8 operatively coacts with the
rocker. This latch memeber 8 is also pivotally
mounted about a pivot 9 which may also be
supported as the pivot 7. Both the latch member 8
and the intermediate rocker 6 are moulded, for
example, injection moulded, from a synthetic
plastics material, such as acetal. The member 8
comprises jaws 10 at one end and a resilient
energy storing extension 11 at the other. The jaws
are operative to engage in the apertures 12 of an
extrusion 13 which is part of or attached to for
example, the lid (not shown) of the cash box
mentioned earlier. The extension 11 coacts with an
elongate flexible synthetic plastics material
(again such as acetal) dependant projection 14 to
impose a load on that extrension 11 against the
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natural residence o~ the material in the locked
position of the mechanism shown in Figure 1.
'
To unlock the mechanism, power is applied to
the solenoid. This withdraws the moveable
actuator rod 2 into the housing 5 of the solenoid
against the action of the compression spring 4
thus compressing the spring (not shown on Figure ~ -
2). The withdrawal of the actutor rod 2 pivots
the intermediate rocker 6 anticlockwise about its
pivot 7. This in turn releases the latch member 8
which pivots clockwise about its pivot thus
releasing the energy stored in the resilient --
exension 11. A stop 15 abutts the surface of the
15 latch member 8 to limit this clockwise movement. -~
The relative disposition of the extension 11 and
the dependant projection 14 are such that their
tips slide past one another. The clockwise
movement of the latch member 8 withdraws the jaws
10 from the aperture 12 thus releasing the
extension 13 and with it the lid of the cash box
(which itself may be spring loaded).
When power is removed from the solenoid 1,
the compression spring 4 acts to return the rod 2
to its original position in turn returning the
intermediate rocker 6 to its original position (as
shown in figure 1) where it can again be contacted
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2008791
by the latch member 8. This contact is actually
renewed on closing the lid of the cash box (not
shown). This closure action results in the lower
end of the extension 13 contacting the lower jaws
of the jaws 10, pivoting the latch member 8 in an
anticlockwise direction and reengaging the upper
jaws of the jaws 10 in the aperture 12 to lock the
mechanism. This anticlockwise movement of the
latch member 8 also causes the tips of the
projection 14 and extension 11 to slide past one
another in the reverse dirction to hitherto,
further movement compressing the extension 11 and
storing energy in it for the next unlatching
operation. In addition the end of the latch
member 8 remote from the jaws 10 reengage in the
intermediate rocker 6. The parts of the mechanism
are then in the position shown in Figure 1 once
again.
The shape of the external periphery of
various parts of the mechanism are carefully
chosen to assist operation. These include the
lower surface 20 of the extension 13 and upper
surface 21 of the lower jaw 10, the tips 22 and 23
25 of the projection 14 and extension 11 respectively
and the end 24 of the latch 8 and lower part 25 of
the rocker 6. These shapes are curved to
facilitate movement over one another,
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Apart from simplification compared with
conventional latching mechanisms, maintenance
requirements such as lubrication are also reduced.
,
Referring to Figure 3, a modified form of the
mechanism described with reference to Figures 1 and
2 is shown incorporated in a cashbox 30. The cashbox ~ -
comprises a base 31 and a lid 32. In this modified
form, the latch mechanism is the same except that
the energy storing extension 11 is shorter and does
not abutt the dependent projection 14 and a
conventional tension spring 33 is connected between
the member 8 and a fixed point operative to urge the
member 8 in a clockwise direction to replace the
force provided by projection 14 in the previous
embodiment. Equivalent parts bear the same
reference numerals in both embodiments. In
addition, a hood 34 is provided to cover the jaws
10 of the latch member 8 to avoid inadvertent
depression of the latch.
lt will be appreciated that the above embodiment
has been described by way of example only and that many
variations are possible without departing from the
invention. For example, although acetal has been
described as the preferred material, other materials
having the required inherent resilience could equally
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Z008791
well be used. Furthermore, there are many other
purposes for which the latching mechanism may be used
other than for a cash box. The solenoid could be
replaced by a wholly mechanical actuator or such an
actuator could be provided in addition to the solenoid.
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