A NEW OR IMPROVED METHOD OF LOCKING THE JOISTS OF STAGES FOR THEATRICAL PERFORMANCES
Year: 1873

page_text: LETTERS PATENT to Tom Walford Grieve, of Charles Street, Drury
Lanc, in the County of Middlesex, Artist, for the Invention of
"A NEW OR IMPROVED METHOD OF LOCKING THE JOISTS OF STAGES FOR
THEATRICAL PERFORMANCES."
Scaled the 18th July 1873, and dated the 25th January 1873.
PROVISIONAL SPECIFICATION left by the said Tom Walford Grieve
at the Office of the Commissioners of Patents, with his Petition,
on the 25th January 1873.
I, TOM WALFORD GRIEVE, of Charles Street, Drury Lane, in the
County of Middlesex, Artist, do hereby declare the nature of the said
Invention for "A NEW OR IMPROVED METHOD OF LOCKING THE JOISTS OF
-STAGES FOR THEATRICAL PERFORMANCES," to be as follows :—
The joists of the stage of a theatre are usually locked together by lock
irons bolted to one joist or its support, and hooking into a staple on the

page_text: next joist or its support. This arrangement is open to the great objection
that the locking is not self-acting, and that in case of any neglect on the
part of the cellarman in charge of this duty on the opening of a "slider"
the adjoining joists on either side may play, and any performer on that
part of the stage may fall through to the cellar or bo thrown down and 5
injured.
The object of my Invention is to obviate all danger of such accidents,
for which purpose I propose to form a groove running longitudinally
along cach joist, and to place across each "slider" at such intervals as
may deem most desirable cramp irons, the flanges of which will ride in 10
the grooves on the joists, and thus the simple closing of the "slider"
will of necessity lock the joists.
I
In order that the "sliders" may pass under the fixed flooring in the
usual manner, the grooves on the joists will be inclined immediately in
front of the fixed flooring, and when the "slider" is closed the end will li
be forced up by a lever as now practised.
To prevent any lateral motion of the flanges of the cramp irons in
the grooves, and to make them run casily, I propose to fit them with a
friction roller.
In lieu of cramp irons placed across the "slider," separate flanges not 20
connected by cross bar might be placed on each section thereof, and
other variations might be made while retaining the essential feature of
my Invention, namely, causing the "slider" and joist to lock together
by tongue and groove whether the catch be on the joist and the groove
or the "slider," or vice versa.
21
SPECIFICATION in pursuance of the conditions of the Letters Patent
filed by the said Tom Walford Grieve in the Great Seal Patent =
Office on the 23rd July 1873.

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-fifth day of January, in the year
of our Lord One thousand eight hundred and seventy-three, in the thirty-
sixth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Tom Walford Grieve, Her special Licence
that I, the said Tom Walford Grieve, my exccutors, administrators,
and assigns, or such others as I, the said Tom Walford Grieve, my
executors, administrators, and assigns, should at any time agree with,
and no others, from time to time and at all times thercaſter during the
term therein expressed, should and lawfully might make, use, exercise, .
and vend, within the United Kingdom of Great Britain and Ireland,
the Channel Islands, and Isle of Man, an Invention for "A NEW OR IM-
PROVED METHOD OF LOCKING THE JOISTS OF STAGES FOR THEATRICAL PERFORMANCES,"
upon the condition (amongst others) that I, the said Tom Walford
Grieve, my executors or administrators, by an instrument in writing
under my, or their, or one of their hands and scals, should particularly
describe and ascertain the nature of the said Invention, and in what
manner the same was to be performed, and cause the same to be filed
in the Great Scal Patent Office within six calendar months next and
immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Tom Walford Grieve, do hereby
declare the nature of my said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained
in and by the following statement :-
The joists of the stage of a theatre are usually locked together by lock
irons bolted to one joist or its support, and hooking into a staple on the
next joist or its support. This arrangement is open to the great objection
that the locking is not self-acting, and that in case of any neglect on the
part of the cellarman in charge of this duty on the opening of a "slider"
the adjoining joists on either side may play, and any performer on that
part of the stage may fall through to the celler or be thrown down and
injured.
The object of my Invention is to obviate all dangor of such accidents,
for which purpose I form a groove or guide running longitudinally
along cach joist, and place across each "slider" at such intervals as I
may deem most desirable cramp irons, the flanges of which ride in the

page_text: grooves or guides on the joists, so that the simple closing of the "slider"
of necessity locks the joists.
In order that the "slidors"
may pass under the fixed flooring in the
usual manner, the grooves or guides on the joists are inclined imme-
diately in front of the fixed flooring, and when the "slider" is on, that 5
is to say closed, the ends are forced up by a lever as now practised.
To prevent any lateral motion of the flanges of the cramp irons in
the grooves, and to make them run casily, I may fit them with a friction
roller.
On the accompanying Sheet of Drawings Figure 1 is a section of a 10
stage, or through a stage, embodying my Invention, showing position of
slider and joists when on; Figure 2 is a plan of samo; and Figure 3 is
a cross section through a pair of joists, showing groove and cramp
irons.
A is the joist, and B is the slider running in the grooves C, C, to the 15
under sides of which are attached the cramp irons D to which are
attached the guide rollers E working against the guides F. G is the
lever for raising slider in position when on, in combination with the
rods H.
Although I give preference to the use of cramp irons passing from 20
side to side of the sliders, as shown on the Drawing, it will be evident
that I might use shorter cramp irons extending only partly across the
slider; also that the cramp irons, whether entirely or only partially
crossing the sliders, may be placed at any suitable distance apart; further,
that the arrangement might be reversed, the catches or cramp irons being 25
on the joists, and the grooves or guides on the sliders.
The cramp irons, guides, and rollers may be made of iron or any suit-
able metal or material.
Having now described and ascertained the nature of my said Inven-
tion, and in what manner the same is or may be performed, I would have 30
it distinctly understood that I do not confine myself to the precise
details herein set forth and illustrated on the accompanying Sheet of
Drawing, as such might be varied without departing from the nature of
my said Invention, and that what I claim as secured to me by the
herein-before in part recited Letters Patent is, the use of the method 35

page_text: herein-before described of locking the joists of stages for theatrical per-
formances, substantially as set forth.
In witness whercof, I, the said Tom Walford Grieve, have here-
unto set my hand and scal, this Twenty-third day of July, in
the year of our Lord One thousand cight hundred and seventy-
three