Improvements in or relating to Locking-devices for Sheet Metal Boxes and the like.
Year: 1896

page_text: Date of Application, 17th Mar., 1896-Accepted, 18th Apr., 1896
COMPLETE SPECIFICATION.
Improvements in or relating to Locking-devices for Sheet Metal
Boxes and the like.
A communication from LUDWIG GEORG BIERLING, Manufacturer, of Muegeln
District of Dresden, in the Empire of Germany.
I, ALFRED JULIUS BOULT of 323 High Holborn, in the County of Middlesex,
Chartered Patent Agent, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and.
ascertained in and by the following statement :-
The locking device forming the subject of the present invention is to be used for
metallic vessels, like boxes, canisters, pails and the like, which are round, oval or
polygonal in plan. For locking it is necessary simply to press the cover on the
vessel as in well-known locking devices used for boxes and acting by friction, in
which a cylindrical edge of the cover surrounds the edge of a cylindrical vessel..
But as compared to such locking devices, the present one gives a much better and
tighter locking, without necessitating special devices for pressing the cover-such
as screw threads, press-screws, wedges, or eccentrics. The new locking devices
withstand such shocks and knocking, as in the manipulation and shipping of boxes
with ordinary locking devices would produce opening of the cover; therefore the
metal boxes with the new locking device are, unlike the ordinary boxes, suitable for
containing fluids. The vessels are closed by that locking device in a completely
airtight and watertight manner and if there be no seam on the vessel (that is to
say, when the vessels are drawn or pressed vessels) the vessel will be completely
fluid-tight; this locking device enables an elastic packing ring to be employed and
to be pressed as strongly, as hitherto was only possible by the above-named special
devices for pressing the cover down in place.
The improved locking device is characterised by two beads, formed by rolling
up the sheet metal, one bead at the edge of the cover and the other at the edge of
the vessel, which beads are forced or sprung past each other, when the cover is
put on, both beads yielding to each other. When the greatest diameter of the
inner bead has passed through the smallest diameter of the outer bead, the beads
spring again into their normal shape and position and the bead on the edge.
of the vessel is gripped by the cover and its bead. This is clear from the
accompanying drawing wherein
Fig. 1 is a vertical central section through a box provided with one construction
of locking-device according to this invention.
Fig. 2 being a similar view showing an alternative construction of locking
device.
In Fig. 1 A is a flat metallic box, and B is its cover. The bead b of the latter
is bent downward and inward, the bead a of the box A being bent upward and
outward so that it rests directly against the edge of the box A. The left-hand
half of the figure shows, how the bead a is yieldingly pressed in the space
between B and b with a tendency to expand outward. According to the
right-hand half of the figure, an elastic strip c is used for completing the
packing, this strip being pressed in between the underside of the cover and the top
of the bead a.
The construction illustrated in Fig. 2 has the advantage of not having any
projecting parts in the locking device. The cover B has an edge b', strengthened

page_text: by being bent double as shown the bead 62 being bent downward and to the
outside. The bead a' of the vessel A is correspondingly bent to the inside. In
the right half of this figure also there is shown a packing ring c. In this mode of
construction the cover can be taken off by introducing a wedge shaped tool between
the flange b' and the bead a¹.
This invention is equally applicable whether the cover be flat or domed; whether
the cover plate rest directly on the edge of the vessel or the cover bead be on a
depending edge of the cover, forming practically a continuation of the cylindrical
or prismatical side of the vessel.
Having now particularly described and ascertained the nature of the said inven-
tion, as communicated to me by my foreign correspondent, and in what manner the
same is to be performed, I declare that what I claim is ;-
1. A locking device for metal-vessels characterised by beads produced by
bending over the edges of the cover and of the vessel these beads formed by rolling
over the metal yielding to each other when the cover is being put on till the largest
diameter of one bead had passed through the smallest opening of the other bead for
the purpose described.
2. A locking device for metallic vessels characterised by the bead b on the cover
being bent downwards and inward from its outer edge, and by the beads a on the
vessel edge being bent outwards substantially as and for the purpose described.
3. A locking device for metal vessels characterised by the bea1 62 of the cover
inside the doubled edge being bent downwards and to the outside the bead a'
directly on the edge of the vessel being bent inside substantially as and for the
purpose described."
Dated this 17th day of March 1896
BOULT & WADE,
Agents for the Applicant.