Improvements in Roberval Balances.
Year: 1899

page_text: Date of Application, 25th Apr., 1859
Complete Specification Left, 25th Jan., 1900-Accepted, 10th Mar., 1900
PROVISIONAL SPECIFICATION.
Improvements in Roberval Balances.
I, EMILE BOCKSTAEL, Junior, of Digne du Canal, Brussels, in the Kingdom
of Belgium, Mechanic, do hereby declare the nature of this invention
to be as follows:
This invention relates to balances of Roberval's system in which a counter
beam parallel with the main beam, connects downward extensions of the scale
pan holders and has bearing from opposite sides against a central abutment
within the base or stand of the balance within which this counter beam is usually
concealed.
This abutment has hitherto been made out of a single piece of cast metal and
its four abutting surfaces have hitherto required to be trued up by a lengthy
and unsatisfactory method of separate trial until the adjustment was found to
be correct.
By the present invention I form the four abutting surfaces on two pieces, two
on each, these pieces being preferably produced mechanically so as to be always
uniformly produced. These pieces have bases or plates to slide in a groove or
recess in or under the cover part of the enclosed base or stand of the balance to
be separately secured by screws passing through slots.
To attain adjustment a template or rule is first inserted, this device being of
a given length and having a stud to fit into one of the holes in the base cover
through which ordinarily the extensions of the scale pan holders pass Having
fitted the stud in such hole, the end of the template or rule will indicate the
central vertical plane of the fulcrum of the balance and it is sufficient to slide
one of the abuttment pieces up to and against the end of the template and to
secure it in position. The template is then removed and the second abutment
pieces slid into the groove, brought up to and against the abutment piece
previously secured, and similarly secured in place.
A further improvement relates to the holders for the knife edges on the scale
pan holders.
This part of the balance which forms a frame surrounding the ends
of the scale beam above below and to the front and rear, is, according to this
invention made in two parts an upper part of steel and a lower part of cast
iron for example so that the upper part may be made true for receiving the
knife edges without the need of providing special bearings which had to be
subsequently fitted to the frame for receiving such knife edges in previous
constructions of this balance.
Dat this 05th daw a A1 1900
HERBERT HADDAN & Co.,
Agents to Applicant.

page_text: I, EMILE BOCKSTAEL, Junior, of Digne du Canal, Brussels, in the Kingdom
of Belgium, Mechanic, do hereby declare the nature of this invention
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
-
This invention relates to balances of Roberval's system in which a counter
beam, parallel with the main beam connects downward extensions of the scale
pan holders and has bearing from opposite sides against a central abutment
within the base or stand of the balance within which this counter beam is usually
concealed.
This abutment has hitherto been made out of a single piece of cast metal and
its four abutting surfaces have hitherto required to be trued up by a lengthy
and unsatisfactory method of separate trial until the adjustment was found to
be correct.
By the present invention I form the four abutting surfaces on two pieces, two
on each, these pieces being preferably produced mechanically, so as to be always
uniformly produced. These pieces have bases or plates to slide in a groove or
recess in or under the cover part of the enclosed base or stand of the balance to
be upwardly secured by screws passing through slots.
To attain adjustment a template or rule is first inserted, this device being of
a given length and having a stud to fit into one of the holes in the base cover
through which ordinarily the extensions of the scale pan holders pass. Having
fitted the stud in such hole the end of the template or rule will indicate the
central vertical plane of the fulcrum of the balance and it is sufficient to slide
one of the abutment pieces up to and against the end of the template and to
secure it in position. The template is then removed and the second abutment
piece slid into the groove brought up to and against the abutment piece
previously secured and similarly secured in place.
A further improvement relates to the holders in the knife edges on the scale
pan holders. This part of the balance which forms a frame surrounding the ends
of the scale beam above, below, and to the front and rear, is according to this
invention made in two parts, an upper part of steel and a lower part of cast
iron, for example, so that the upper part may be made true for receiving the
knife edges without the need of providing special bearings which had to be
subsequently fitted to the frame for receiving such knife edges in previous
constructions of this balance.
Referring to the annexed drawing which represents a Roberval balance pro-
vided with my improved abutment.
Fig. 1 is a front view of the balance, with the base or stand-cover partially
removed.
Fig. 2 is a transverse section of the base, or stand of the balance.
Fig. 3 is a plan view of the counter beam.
Figs. 4 and 5 are respectively a horizontal and vertical view of a template,
the purpose of which is hereinafter described.
Figs. 6 and 7 are sections of the holders for the knife-edges on the scale pan
holders, showing certain improvements.
The abutment 1, with four abutting surfaces 2, 3, 4 and 5, is according to
my invention made of two separate steel pieces, 6 and 7, which are produced
mechanically in order to insure absolute uniformity in the surfaces 2, 3, 4 and 5.
In the base or stand of the balance is a groove 8-9 into which the corresponding

page_text: bases or plates of the abutment parts 6 and 7 are dove-tailed in such a manner as
to slide along the groove.
The abutment is adjusted in the following manner:-
Bored through the base or stand cover of the balance are the holes 10 and 11
for the rods 12 of the scale pan holders 13 to pass through. Into one of these
holes 10 and 11 the stud 14 of a template or rule 15 is inserted. As the stud 14
fits exactly into the hole 10 or 11 and the length of the template or rule 15
corresponds exactly to half the distance between the holes 10 and 11 the end of
the template or rule 15 will indicafe with the greatest possible exactitude the
centre of the balance. To adjust the abutment, one of the parts 6 and 7 is
pushed along the groove 8-9 up to and against the end of the template 15,
where it is secured by one of the screws 16, which passes through a suitable slot.
The template is then removed and the other part of the abutment is pushed along
the groove 8-9 up to and against the part previously secured. The surfaces 2,
3, 4 and 5 will then be exactly in the positions which they should occupy.
Besides having the advantage of being more simple, this method of construction
ensures complete accuracy, the adjustment of the abutment being governed by
an exact system and not by a method of tests and trials.
A further improvement consists in making each holder (13) for the knife edges
on the scale pan holders in two separate parts 17 and 18, of which the upper
one is made of steel, so as to obviate, as shown in Figs. 6 and 7, the necessity
of providing special bearings, which had to be subsequently fitted to the holders
in previous constructions. The upper steel part 17 and the lower, cast iron
part 18, forming together the holder 13, can be produced mechanically, which
conduces to far greater accuracy in this part of the balances than has hitherto
been achieved.
Having now particularly described and ascertained the nature of this
invention and in what manner the same is to be performed, I declare that what
I claim is:-
1. In a Roberval balance an abutment for the counter beam consisting of two
separate pieces, two of the abutting surfaces being on each of the said pieces
and each of the said pieces being arranged to slide along a groove in the base
or stand of the balance so as to approach each other thereby facilitating and
rendering more accurate the adjustment of the abutment in the central vertical
plane of the balance.
2. In a Roberval balance provided with the improved abutment in Claim 1,
for the purpose of facilitating the adjustment of the pieces forming the said
abutment, a template or rule (15) with a stud (14), which latter fits exactly
into the holes through which the scale pan holders pass, the distance from the
centre of the said stud to the opposite end of the said template or rule corre-
sponding to half the distance between the two holes through which the scale pan
holders pass.
i
3. In a Roberval balance, holders (13) for the knife edges of the scale pan
holders made in two separate parts, of which the upper one is made of steel, so
that the bearings can be made mechanically in the part itself, and the necessity
of subsequently fitting bearings to the part is obviated.
Dated this 25th day of January 1900
HERBERT HADDAN & Co.,
Agents to Applicant.
18, Buckingham Street, Strand, W.C., London.