AN IMPROVE- MENT IN THE GAS BAG PRESSURE FRAMES FOR DISSOLVING VIEW AND OTHER OPTICAL APPARATUS
Year: 1884

page_text: I JOHAN AUGUST DALÉN of 13 Ward Street West Hartlepool in the County
of Durham, do hereby declare the nature of the said invention for "AN IMPROVE-
MENT IN THE GAS BAG PRESSURE FRAMES FOR DISSOLVING VIEW AND OTHER
OPTICAL APPARATUS " to be as follows:-
My invention relates to an improvement in pressure frames or boards for the gas
bags of dissolving view and other optical apparatus and it has for its object to
avoid the liability to accident to which such pressure boards or frames as now
generally constructed are subject to ensure a more uniform pressure on the gas;
to avoid the necessity of adjusting the pressure apparatus whilst in use and to
render the apparatus more conveniently portable.
Heretofore the pressure boards consist of a pair of boards or frames binged
together and forming a shaped contrivance between which the bags are placed,
the lower board or, frame being hinged to a foot board and supported by a strut
and the upper one loaded with weights.
Such pressure boards or frames are liable (unless readjusted at the proper time)
to overturn in consequence of the weights passing beyond the base and the weights
are apt to slip off, thus giving rise to dangerous accidents by the rupture of the
pipes the extinction of the light &c. Moreover the pressure exerted on the bags
is in all cases unequal owing to the varying leverage with which the weights act
on the pressure board or frame.
To overcome the objections above mentioned both boards or frames are by my
invention caused to descend together as the gas is consumed instead of the upper.
one only descending as hitherto thereby ensuring a parallel or vertical motion of
the loaded end of the upper board and this I accomplish by means of one or two
rigid extensions or legs affixed to the upper board or frame and projecting beyond
the hinge connection of the boards or frames a sufficient distance to rest upon the
floor and support the pair of frames or boards in position these legs being furnished
with rollers to ensure a smooth and equal action free from jerks.
As the bags collapse the rollers run along the floor, the pressure boards or
frames closing together and the whole apparatus sinking down to a horizontal
position.
:

page_text: .
By this means I am enabled to dispense with the usual footboard and strut
and the upper loaded board and frame can never pass the horizontal and be
inclined in the reverse direction as now occurs when the bags are less than
half full.
The extensions or legs may be secured to the upper board in any convenient
-way and may be jointed or otherwise arranged to fold or lay alongside the upper
board or frame when the apparatus is packed for transport.
I JOHAN AUGUST DALÉN, of 13, Ward. Street, West Hartlepool, in the County
of Durham, do hereby declare the nature of the said invention for "AN IMPROVE-
MENT IN THE GAS BAG PRESSURE FRAMES FOR DISSOLVING VIEW AND OTHER
OPTICAL APPARATUS," and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement :-
My Invention relates to an improvement in pressure frames or boards for the
gas bags of dissolving view and other optical apparatus, and it has for its objects to
avoid the liability to accident to which such pressure boards or frames as now
generally constructed are subject; to ensure a more uniform pressure on the gas;
to avoid the necessity of adjusting. the pressure apparatus whilst in use; and to
render the apparatus more conveniently portable.
The pressure boards or frames between which the bags are placed are usually
hinged together but the lower board or frame has heretofore been rigidly although
adjustably supported by a strut the upper one alone being movable under the
pressure of the weights with which it is loaded. The pressure boards or frames
so supported are liable (unless readjusted at the proper time) to overturn in
consequence of the angular motion of the upper board carrying the weights
beyond a vertical falling within the base; and the weights unless fastened are
apt to slip off when the bags are nearly empty thus giving rise to dangerous
accidents by the rupture of the pipes the extinction of the light &c: Moreover
the pressure exerted on the bags constantly varies owing to the varying leverage
with which the weights act on the pressure board or frame.
To overcome the objections above mentioned both boards or frames are by my
invention caused to descend together as the bags collapse instead of the upper one
only descending as hitherto, thereby ensuring a nearly rectilineal vertical motion
of the loaded end of the upper board and this I accomplish by supporting the
frames.in position by means of a rigid prolongation of the upper board or frame,
said prolongation extending beyond the hinge connection of the boards or frames
a sufficient distance to rest upon the floor at about the same angle therewith as the
lower frame.
This prolongation is preferably in the form of a pair of legs and these legs
are furnished with rollers to ensure a smooth and equal action free from jerks.
As the bags collapse the rollers run along the floor and allow both of the
pressure boards or frames to sink down towards a horizontal position whilst closing
together.

page_text: By this means I am enabled to dispense with the usual footboard and strut
and the upper board can never pass beyond the horizontal plane and be inclined
in the reverse direction as now occurs when the bags are less than half full.
The extensions or legs may be secured to the upper board in any convenient
way and may be jointed or otherwise arranged to fold or lay alongside the upper
board or frame when the apparatus is packed for transport.
Reference is to be had to the accompanying drawings forming part of this
Specification wherein the construction and working of the apparatus is fully
illustrated. In sheet 1 Figure 1 is a side elevation, Figure 2 an end elevation,
Figure 3 a plan, and figure 4 a perspective view of the apparatus as in use.
Figures 5 and 6 show the frame folded for transport. Sheet 2 shows details on
a larger scale. A B are the two frames constructed of side and cross pieces tenoned
together and the whole bound with iron as usual. The upper frame A is hinged
at a to the lower frame B as in figure 7 Sheet 2. To the hinged end of the
frame A are rigidly secured two extensions or legs C C furnished with small
rollers cat their extremities, shown in figure 8 sheet 2. When the gas bags are
in position between the frames as in figures 1 and 4 the apparatus rests on the free
end of the frame B and on the above mentioned rollers and as the bags collapse
the rollers gradually run forward, so that the frame B receives an angular motion
about its lower edge as a centre corresponding in extent to the angular motion of
the frame A about its hinge; the whole apparatus thus sinking down bodily as
shown by the dotted lines in figure 1. The upper end of the frame A, on which
are placed the weights, resting against the ledge b thus descends in a nearly
vertical line so that this arrangement renders the overbalancing of the apparatus
an impossibility, and obviates the necessity of any attention to, or adjustment of,
the weights during operation.
The legs C are preferably pivoted to the frame A as shown in figure 7 so as to
fold into a compact and easily portable form. Each leg C is pivoted to the hinged
end of the frame A by a screw d which is firmly screwed through the frame A into
a nut d¹ at the underside thereof until it comes down on the shoulder e so that the
leg can readily be turned on the screw as a pivot.
The pivoted end of the leg is preferably faced with a metal plate m to prevent
abrasion of the wood against the head of the screw d.
The leg is fixed in working position by means of a thumb screw f inserted
through a hole in the leg near its pivot and screwed into a threaded socket or nut g
let into the frame A.
When the apparatus is to be folded for carriage the thumb screw f is unscrewed,
the leg is turned into the position shown in figures 5 and 6 and the thumb screw
is inserted through another hole h near the other extremity of the leg through a
corresponding hole in frame A and screwed into a nut i in the frame B whereby
the frames A B are kept folded for transport.
Recesses of suitable form are made in the upper end of the-frame A in order
to receive the rollers c of the legs when the apparatus is folded up. The bags are
kept in position between the frames by a stout leather strap passed through a slot
in the upper frame A at n round the rear ends of the bags through a hole in the
canvas that separates the two bags, then through the hole o, its ends being united
by a buckle.
Having now particularly described and ascertained the nature of the said
Invention, and in what manner the same is to be performed I declare that what
I claim is
1. A gas bag pressure apparatus in which the hinged pair of pressure frames or
boards are so supported in working position as to both have an automatic and
simultaneous angular motion about opposite centres so as to sink together as the
bags collapse substantially as specified.
2. A gas bag pressure apparatus in which the hinged pair of pressure frames or
boards are supported in working position by one or more rigid extensions of the
upper frame substantially as herein specified whereby the two frames are free to

page_text: have a simultaneous angular motion about opposite centres and so sink together
as the bags collapse.
3. A gas bag pressure apparatus in which the hinged pair of frames or boards
are supported in working position by one or more rigid extensions of the upper
frame furnished with' rollers to 'run on the floor, said extensions making with
the floor about the same angle as the lower pressure board substantially as
described.
4. A gas bag pressure apparatus in which the hinged pair of pressure boards or
frames are supported in position by a pair of legs forming rigid extensions of the
upper frame when in use, the said legs being pivoted to the said frame, so as to fold
thereon for transport substantially as shown and described.
n"