IMPROVEMENTS IN SPRING BALANCES OR SPRING WEIGHING MACHINES
Year: 1881

page_text: "
PROVISIONAL SPECIFICATION left by Charles Maschwitz at the Office of
the Commissioners of Patents on the 31st May 1881. A communication from
abroad by Eduard Ferdinand Grell, of Hamburg, Merchant.
CHARLES MASCHWITZ, of Birmingham, in the County of Warwick, Merchant.
IMPROVEMENTS IN SPRING BALANCES OR SPRING WEIGHING MACHINES."
[A communication from abroad by Eduard Ferdinand Grell, of Hamburg,
Merchant.]
This Invention has reference to spring balances or spring weighing machines for
weighing articles of food and the like, and commonly called domestic balances. In
weighing articles which require to be held in a dish, holder, or vessel, the weight
or "taro" of the dish, holder, or vessel has to be deducted from the gross weight
indicated on the dial plate to ascertain the true weight of the article.
This Invention has for its object principally so to construct the spring balance
or spring weighing machine that the pointer or index finger can readily be
brought to and maintained at the zero or starting point of the dial plate before
proceeding to weigh the article placed in the dish, holder, or vessel, so that the
weight of the article is indicated on the dial plate instead of its weight, plus the
weight of the dish, holder, or vessel containing it.
The spring balance or spring weighing machine to which the Invention refors
consists of a vertical case in which a sliding frame works. The upper part of the
said frame projects from the head of the case and carries a disc upon which the
article to be weighed is placed; or a scale pan is attached to the disc on which the
article to be weighed is placed. The descent of the frame by the weight placed
upon it elongates a coiled or helical spring, the motion of the frame being
transmitted by a rack and pinion to the axis of a pointer or index finger, the
weight being indicated by the pointer traversing the dial plate of the balance.
Instead of connecting the upper end of the helical or coiled spring to the head of
the case of the balance and the bottom end of the said spring to the sliding frame
described, this Invention consists in part in connecting the upper end of the coiled
or helical spring to the bottom of a rod capable only of a rising and falling motion
in the case of the balance. The upper end of this sliding rod projects from the
outside of the case and is screwed. A milled nut or screw box works upon the
Price 11

page_text: screwed end of the sliding rod, and by turning the said nut or screw box in one or
other direction, the said rod may be made to rise or fall. The coiled spring to
which it is attached is thereby made to rise or fall carrying with it the sliding
frame, the motion of which is transmitted to the index finger or pointer through a
rack and pinion.
In using the spring balance or spring weighing machine the dish, holder, or
vessel, in which the article to be weighed is to be placed or held is first put upon
the disk or scale pan of the balance; the coiled spring of the sliding framo is
thereby elongated and the weight indicated on the dial plate. By now turning
the milled nut or screw box in a direction proper to raise the sliding rod upon
which it screws, the motion of the said rod raises the coiled spring and the frame
connected to it, and thereby causes the index finger to return to the zero point on
the dial The article to be weighed is now placed in the dish, holder, or vessel, on
the balance, and the weight of the said article is indicated on the dial plate. The
deduction of the tare or weight of the dish, holder, or vessel, in which the
article is weighed is thereby rendered unnecessary, and the weighing of articles is
thus facilitated. This Invention consists further of the following arrangenent of
parts for connecting the scale pan to the disc of the balance or weighing machine.
On the underside of the scale pan is a semi-circular pocket of slightly larger
diameter than the disc of the balance. At the middle of the scale pan is a raised
lip or flange concentric with the semi-circular pocket described, the said lip corre-
sponding with a rim on the upper face of the disc.
"
In connecting the scale pan to the disc the open end of the pocket part of the
When the
pan is presented to the disc and pushed thereon by a sliding motion.
semi-circular pocket has passed onto the disc the circular lip or flange on the scale
pan engages with the rim on the upper face of the disc and the scale pan is securely
fixed to the disc. By pressure upon the scale pan in the opposite direction, its lip
is lifted from the rim on the disc and the scale pan may be removed by a sliding
motion.