IMPROVEMENTS IN FLOOR CRAMPS
Year: 1870

page_text: LETTERS PATENT to Francis James Barnby, of Hull, in the County of
York, for the Invention of "IMPROVEMENTS IN FLOOR CRAMPS."
.
Sealed the 15th July 1870, and dated the 25th January 1870.
PROVISIONAL SPECIFICATION left by the said Francis James Barnby
at the Office of the Commissioners of Patents, with his Petition,
on the 25th January 1870.
I, FRANCIS JAMES BARNBY, of Hull, in the County of York, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN FLOOR
CRAMPS," to be as follows:-
My Invention relates to an improved construction of floor cramp by
which previous adjustment is rendered unnecessary.
The improved cramp can also be applied within a short distance of
the end of the floor board or within the space of the last floor board
to be laid.
My improved cramp consists of a lever forked at its lower end to span
the joist of the floor. The two limbs of the fork are parallel and are
turned cylindrical to receive the two jaws of the cramp, which are

page_text: pro-
pivoted loosely thereon. Each of these jaws is shaped in the segment of
a circle and pivoted eccentrically towards one end, where it is provided
with an inclined projection or cam formed on the under side of the jaw.
Each jaw rests on a block or washer fixed at the extremities of the fork
and provided with a corresponding inclined cam surface to fit the
jection on the jaw. In this manner when the jaws are opened or swing
round on their pivots they will be caused to rise thereon by the inclined
cam surfaces, and will thus when opened have a constant tendency to
close together. The curved or gripping surfaces of the jaws are serrated
or provided with inclined teeth to prevent slipping. Near the upper
part or handle of the lever is jointed a back stay or strut, the lower end
of which is sharpened to obtain a hold on the surface of the joist and so
maintain the cramp in position when applied against a board.
In order to apply the cramp the jaws, which are closed when in their
normal position, are pressed apart by the edge of the joist to admit the
latter between them and permit of the cramp being drawn up to its
work. The jaws from their constant tendency to close clasp the joist--
firmly between them and form a fulcrum or point of resistance for the
lever or cramp when drawing the same up against a board, and the
gripping surfaces being curved eccentrically, as before described, will
grip the joist more tightly the greater the force applied to the handle,
while the pull on the joist being longitudinal will not displace or bend
.it. To apply the cramp within the space of the last board the back stay
is removed and the cramp applied to the joist as before.
:
SPECIFICATION in pursuance of the conditions of the Letters Patent, 25
fled by the said Francis James Barnby in the Great Seal Patent
Office on the 23rd July 1870.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FRANCIS -
JAMES BARNBY, of IIull, in the County of York, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her 30
Letters Patent, bearing date the Twenty-fifth day of January, in the
year of our Lord One thousand eight hundred and seventy, in the thirty-
third year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Francis James Barnby, Her special licence
that I, the said Francis James Barnby, my executors, administrators, and 35

page_text: assigns, or such others as I, the said Francis James Barnby, my executors,
administrators, and assigns, should at any time agree with, and no
others, from time to time and at all times thereafter 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 "IMPROVEMENTS IN
FLOOR CRAMPS," upon the condition (amongst others) that I, the said
Francis James Barnby, my executors or administrators, by an instrument
in writing under my, or their, or one of their hands and seals, 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 Seal Patent Office within six calendar
months next and immediately after the date of the said Letters
Patent.
NOW KNOW YE, that I, the said Francis James Barnby, 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, reference being had to the Sheet of Drawings
hereunto annexed, and to the letters and figures marked thereon (that
is to say):-
My Invention relates to an improved construction of floor cramp by
which previous adjustment is rendered unnecessary.
The improved cramp can also be applied within a short distance
of the end of the floor board or within the space of the last floor board
to be laid.
My improved cramp consists of a lever forked at its lower end to
span the joist of the floor. The two limbs of the fork are parallel and
are turned cylindrical to receive the two jaws of the cramp which are
pivoted loosely thereon. Each of these jaws may be shaped in the
segment of a circle and pivoted eccentrically towards one end, where it
is provided with an inclined projection or cam formed on the under
side of the pivoted part of the jaw. Each jaw rests on a block or washer
fixed at the extremities of the fork and provided with a corresponding
inclined cam surface to fit the projection in the jaw. In this manner
when the jaws are opened or swung round on their pivots they will be
caused to rise thereon by the inclined cam surfaces, and will thus when
opened have a constant tendency to close together. The curved or
gripping surfaces of the jaws are serrated or provided with inclined

page_text: the inclined surfaces 6 and close or swing together. This closing or
gripping action of the jaws may also be obtained by the aid of springs
connected to the limbs O and acting on the jaws D in any suitablė
manner to close them together, the inclined surfaces being dispensed with
and the jaws merely pivoted to turn freely on the limbs O within limits.
Figures 5 and 6 are a plan and vertical section respectively of
one of the jaws D detached showing one method of applying the
spring d, which is recessed within jaw D, one end being attached
thereto and the other end connected to the pivot C around which it is
coiled. The motion of the jaw is limited by a projection e on the pivot C
engaged in a recess f in the jaw. F is a back say or strut, the one end of
which is jointed to the upper part of the lever A, the other being pointed
or sharpened to obtain a hold on the surface of the joist B, and so main-
tain the pressure of the cramp when applied against a board. H are
the flooring boards, and I is a block interposed between the cramp and
the board to be tightened. The cramp is first applied to the joist, as
shown in dotted line in Figure 1, to open the jaws, which are pushed
apart by the edge of the joist, and the latter being thus admitted between
them the cramp may be drawn up to the line position. Owing to the
constant closing tendency of the jaws obtained by the inclined surfaces
or by springs, as before described, the joist is immediately gripped by
the jaws, so that on power being applied to the other end or handle of
lever A to draw the same up against the block I and tighten the boards
the grip of the jaws D on the joist will (by reason of their eccentricity)
be increased with the power applied to the handle, the jaws thus
forming the fulcrum or point of resistance of the cramp. The strut F
follows or backs up the lever A when power is applied to the latter,
and serves to maintain the cramp in position whilst nailing the board,
as before described. This stay F may be removed if necessary, as when
it is required to apply the cramp within the space of the last board next
the wall for instance.
"
Having described the nature of my Invention, and the manner of
performing the same, I declare that what I claim as my Invention of
improvements in floor cramps, to be protected by the herein-before in
part recited Letters Patent is,—
1st. The excentrically curved pivoted jaws D for automatically grip-
ping the joists, previous adjustment of the cramp being rendered
unnecessary. substantially as shown and described.

page_text: 2ndly. I claim the combination with the forked lover A of the
eccentrically curved jaws D pivoted to the limbs C of the fork, and
operating substantially as and for the purpose set forth.
In witness whereof, I, the said Francis James Barnby, have here-
unto set my hand and seal, this Twenty-first day of July, in the 5
year of our Lord One thousand eight hundred and seventy.
FRANCIS JAMES BARNBY. (L.S.)