IMPROVEMENTS IN PLATFORM WEIGHING MACHINES
Year: 1874

page_text: LETTERS PATENT to John Bartlett, of the City and County of Bristol,
for the Invention of "IMPROVEMENTS IN PLATFORM WEIGHING MACHINES."
PROVISIONAL SPECIFICATION left by the said John Bartlett at the
Office of the Commissioners of Patents, with his Petition, on the
23rd July 1874.
I, JOHN BARTLETT, of the City and County of Bristol, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN PLATFORM
WEIGHING MACHINES," to be as follows:-
My Invention relates to improvements in relieving gear for platform
weighing machines, and in the runner or movable weight on tho steel-
yard.
In platform weighing machines as ordinarily constructed the steelyard
is put out of gear by lowering its fulcrum, but this is objectionable, as
the raising and lowering of the steelyard operates injuriously on the

page_text: fulcrum, whereas by my Invention the steelyard is relieved without
disturbing its horizontal position by entirely disconnecting the connecting
rod coupling it to the platform mechanism.
My Invention consists in a catch jointed to the connecting rod, and
serving to connect the latter to a stirrup hung from the short arm of the
steelyard. The said catch is provided with a horizontal extension or
handle, by which it may be thrown back to disconnect it from the stcel-
yard, and which at same time serves to weight the catch so as to make
it self-connecting. The connecting rod is raised and lowered in order
to put it in and out of gear by means of the ordinary lever handle, which
is connected loosely to the connecting rod by a link.
The runner on the steelyard consist of an independent carriage on
rollers running along the steelyard, in which a weight is mounted to
vibrate on a fulcrum so placed as to give a slight preponderance to the
indicating end of the weight, at which a marker is carried. The weight 1
may be provided with a handle, by which it is oscillated to lift the
marker out of the notches on the steelyard, so that it can be readily
moved with the carriage to the proper point along the steclyard to
indicate the weight of the load on the platform.
SPECIFICATION in pursuance of the conditions of the Letters Patent, 2
filed by the said John Bartlett in the Great Seal Patent Office on
the 23rd January 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, John
BARTLETT, of the City and County of Bristol, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her 2
Letters Patent, bearing date the Twenty-third day of July, in the year of
our Lord One thousand eight hundred and soventy-four, in the thirty-
cighth year of Her reign, did, for Herself, Her heirs and successors
give and grant unto me, the said John Bartlett, Her special licence
that I, the said John Bartlett, my exccutors, administrators, and 3
assigns, or such others as the said John Bartlett, my exccutors,
administrators, and assigns, should at any time agree with, and no

page_text: and out of gear by means of a lever handle, which is attached loosely to
the connecting rod by a suitable link.
The improvement in the runner or weight on the steelyard consists in
mounting it to vibrate on a horizontal axis, and to run on a roller or
rollers along the steelyard, so that it may be readily shifted to any point
in the length of the steelyard, as may be required. To this end a weight
is hung on a horizontal axis supported either in a carriage on rollers,
one at either end, running on the steelyard, or the axis of the weight.
may be mounted on a single roller running directly on the steelyard
without the intervention of any carriage. I prefer the latter arrange-
ment. The axis of the weight is so situated as to give a slight prepon-
derance to the indicating end, or that at which a marker is carried, so
that the latter will readily fall into the notches of the steelyard, and by
a slight pressure of the hand on the other end of the weight the marker
will be lifted out of the notches, and the weight can then bo readily
moved to any point along the steelyard.
Figure 1 shows an end clevation; Figure 2, a side elevation of the
relieving gear of my Invention, the runner or indicating weight being
also shown in the latter Figure, and in cross section in Figure 3. In:
Figure 2 the red lines show the connecting rod detached from the steel-
yard.
I
a is the steelyard, and 6 the connecting rod for coupling the levers
beneath the platform with the steelyard a, through the agency of a self-
acting catch c pivoted at o³ to the upper end of the rod b, and a stirrup
piece hung from the back knife edge e of the steelyard; f is the
relieving lever handle fulcrumed at g to the frame (not shown), and
from whose short end is suspended any suitable connection or link h, by
which to raise the connecting rod. This link is preferably composed of
two side pieces h, h, connected by cross pins /, h³, at top and bottom,
the upper cross pin ¹ resting on a notch in the end 7 of the lever, and
the lower one playing in a slot i in the connecting rod, so as to avoid
interfering with the action of the steelyard when in gear. The catch c
is made self-connecting to the stirrup d by the action of a weighted
extension k, which also serves as a handle to disconnect catch c from

page_text: said stirrup d, or the catch might be acted on by a spring with the same
object. The lever handle f is weighted at in order that it shall imme-
diately resume its original position after putting the apparatus in or out
of gear. In Figure 1 the mechanism is shown in gear for weighing.
To throw it out of gear the lever handle is depressed, thereby raising
the catch c sufficiently to enable it to be readily disconnected from the
stirrup d. On allowing the lever handle f to resume its original position
the connecting rod 6 is lowered and remains suspended from the link h
by the slot i, as seen in red lines. To put the apparatus in gear the
handle is depressed as before, thereby raising the catch c until its
bevelled end strikes against and vibrates the stirrup d, to which it then
connects, as in Figure 1. j is the runner or indicating weight mounted
on a roller m running on the steelyard a. This roller m'is made with a
groove or gorge m³ on its periphery to clear the raised rack of notches n¹
on the steelyard; o is a catch or pointer carried at one end of the weight,
which has a slight preponderance towards this end, that the pointer may
readily fall into the notches. The cross sectional view, Figure 3, shows
the construction of the steelyard, and of the weight which is so formed
as to embrace a flange on the steelyard to prevent the weight being
accidently thrown off.
It will also be seen that the form of the weight is such that its centro
of gravity will be in the central plane of the roller m, so as to hang fairly
thereon.
Figure 4 shows another arrangement, the weight j being hung on an
axis p at either side in a carriage r, supported on two rollers running on
the steelyard, as before.
Having described the nature of the Invention, and the manner of
performing the same, I declare that what I claim as my Invention to be
protected by the herein-before in part recited Letters Patent is,-
1st. The combination with the connecting rod 6 of the catch e pivoted
thereto or its equivalent, and the stirrup piece d or its equivalent, hung
from the steelyard, and with which the said catch is caused to engage
and disengage, substantially as and for the purpose specified.
2ndly. The combination with the subject of clause 1 of the relieving
handle f, weighted as described, and link or connection to raise and
lower the catch c and connecting rod 6, as set forth.

page_text: 3rdly. Mounting the indicator weight to vibrate on a horizontal axis,
supported on a single roller (or in a carriage on rollers) running on the
steelyard, so that the marker may be readily put in or out of the notches
and moved to any point of tho steelyard, substantially as shown and
described.
In witness whereof, I, the said John Bartlett, have hereunto set
my hand and seal, this Twentieth day of January, in the year of
our Lord One thousand eight hundred and seventy-five.
ח חזיוגד'