IMPROVEMENTS IN SPRING IN SPRING BALANCES OR WEIGHING APPARATUS
Year: 1861

page_text: LETTERS PATENT to Thomas Silvester, of West Bromwich, in the County
of Stafford, Manufacturer, for the Invention of "IMPROVEMENTS IN SPRING
Sealed the 24th January 1862, and dated the 14th August 1861.
PROVISIONAL SPECIFICATION left by the said Thomas Silvester at the
Office of the Commissioners of Patents, with his Petition, on the 14th
August 1861.
I, THOMAS SILVESTER, of West Bromwich, in the County of Stafford, Manu-
facturer, do hereby declare the nature of the said Invention for "IMPROVEMENTS
IN SPRING BALANCES OR WEIGHING APPARATUS," to be as follows, that is to say:-
My improvements consist in attaching the spring (in the description of
balances known as Salter's balances) to the bottom instead of the top of the
middle piece or slide, by which I save about a third of the material with the
same size or weight of spring; and instead of employing varnish as heretofore
to preserve the barrels from rust, I galvanize the barrels and also the middle
pieces. In the ordinary balances the spring is always concealed whether in
use or not.
In my improved balance, a short length of the spring is always to be seen
protruding from the bottom of the barrel, and when the whole weight is on
about half the length of the spring is in sight, so that the existence of rust or
damage to the spring is readily ascertained, and lubricating material is easily
applied.

page_text: In making spring balances of the circular form, and which have hitherto
bad the springs exposed at the back of the dial, or concealed altogether, I
enclose them in a case provided with openings at the bottom, through which
the springs work; this case may be either japanned or galvanized to protect it
from rust, and a length of the spring is always in sight, so that in my balance 5
I have the advantage of the protecting case together with that of being enabled
to see the working of the spring.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Thomas Silvester, in the Great Seal Patent Office on the
12th February 1862.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
SILVESTER, of West Bromwich, in the County of Stafford, Manufacturer, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fourteenth day of August, in the year of our Lord
One thousand eight hundred and sixty-one, in the twenty-fifth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Thomas Silvester, Her special license that I, the said Thomas Sil-
vester, my executors, administrators, and assigns, or such others as I, the
said Thomas Silvester, 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,
excrcise, and vend, within the United Kingdom of Great Britain and Ireland,
the Channel Islands, and Isle of Man, an -Invention for "IMPROVEMENTS
IN SPRING BALANCES OR WEIGHING APPARATUS," upon the condition (amongst
others) that I, the said Thomas Silvester, by an instrument in writing under my
ban and seal, 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 Thomas Silvester, 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 Drawings hereunto anuexed,
and to the letters and figures marked thereon (that is to say) :-
My improvements in spring balances consist in attaching the spring (in

page_text: the ordinary hook (G) or scale pan, on which hook or scale pan, the article
to be weighed is placed.
or scale
In Fig. 1 the spring is represented as partly drawn out, but in Fig. 2,
the spring is shewn in its normal position; a shorter or longer portion of
the spring always being visible, whether the apparatus be in use or at rest,
thus admitting at all times of proper inspection, lubrication, and adjustment,
without detaching any portion of the apparatus. In the single spring balance
illustrated at Figs. 3 & 4, the spring (A) is suspended to the top of the
case (B) by the head of the short bolt (C) being inserted above the collar (H),
and to the bottom of this spring is attached the slide or middle piece (E)
carrying the pointer (F) as in the balance already described. The hook (G)
pan, is also hung to the bottom of the slide or middle piece. Fig. 8
represents the spring slightly extended. In Fig. 4 it is shewn at rest. Fig. 5
is a larger single spring balance similarly constructed to that already described;
Fig. 6 is a reversed balance. The spring (A) is attached to the lower end of
the case or barrel (B), and to the top end of the spring is secured the slide or
middle piece (E), through the back of which passes the ring (K), by which
the balance is suspended. In this form of balance I am enabled to dispense
with the dial plate, pointer, and slot in the front plate, for by graduating the
face of the slide or middle piece (E), the top edge of the front plate indicates
the weight that has been placed upon the book (G) or scale pan, which hook
or scale pan is in this instance attached to the bottom end of the front plate
instead of to the middle piece.
16
+
Fig. 8 represents a tubular form of balance to which the description of
the balances shewn in Figs. 4 5 will apply, the same parts being marked
with the same letters as in those Figures. The slide or middle-piece shewn
at Fig. 7 is provided at the top end with two arms or horns (A) upon either
side of the spring (B), keeping the slide steady in its vertical motion, and
preventing the rubbing of the pointer or finger upon the graduated dial plate.
This form of slide or
middle piece I can apply to any of the forms of balances
already described, but to the reversed balance shewn at Fig. 6, it will be seen
that the arms or horns of the slide or middle piece must be at the lower end
of the slide instead of the upper as in the other instances. By thus attaching
the springs of these balances to the lower end of the middle pieces or slides,
leaving a portion of the spring always exposed to admit of ready lubrication,
inspection, or repair, is not the only advantage gained, for by this arrange-
ment a much shorter case is necessary, and thus these balances can be more
economically manufactured; whilst in the reversed form of balance shewn in
1.
SL

page_text: Fig. 6, in which form the positions of the hook (G) and ring (K) may be
exchanged, allowing the weight to be marked by the lower edge of the front
plate instead of the upper, the use of the dial plate, slot, and pointer, or
index is entirely avoided. Hitherto it has been the custom in the making of
these balances to varnish the parts when formed of iron to protect them from
rust. Finding this an inefficient expedient, I galvanize the barrels, and also
the middle pieces, and front plates when made of iron, but I prefer in some
instances to make all these parts in zinc.
Having thus described the nature of my said Invention, and in what manner
the same is to be performed, I claim,--
Firstly, the improvements in the construction of spring balances or weighing
apparatus by connecting the spring to the lower end of the slide or middle
piece represented in Figures 1, 2, 3, 4, 5, & 8, and herein described.
Secondly, I claim the construction of the form of balance represented in
Figure 6, and its equivalent, formed by merely exchanging the positions of
the hook & ring, and both of which forms I have termed the reversed
balance.
Thirdly, I claim the horned middle piece shewn in Figure 7, so designed
for the purpose of steadying the pointer or index, and preventing it from
rubbing the graduated dial.
Fourthly, I claim, making the cases of spring balances of zinc, and also
the galvanizing such parts, and also the slides or middle pieces, instead of
varnishing them when made of iron, as herein more fully set forth and
specified.
In witness whereof, I, the said Thomas Silvester, have hereunto set
my hand and seal, this Tenth day of February, in the year of our Lord
One thousand eight hundred and sixty-two.
SILVESTED
THOMAS SIT VESTED
VWOHL
(2.5.)