Improvements in Calculating Scales."
Year: 1897

page_text: Date of Application, 19th Oct., 1897-Accepted, 24th Dec., 1897
66
'Improvements in Calculating Scales."
I, RUDOLPH CHARLES SMITH, of No. 214 Woodworth Ave., in the City of Yonkers,
County of Westchester, and State of New York, United States of America,
Engineer-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:-
"
My invention relates to improvements in calculating scales or slide rules, by
means of which computations are performed by sliding a slide and stationary
scale, both marked with proper divisions to represent numbers, as is well known;
into such position, that the result of the computation can be ascertained by the
division marks.
The object of my invention is to make an instrument which is portable, light
and cheap, but at the same time protected against wear and tear and of great
handiness in its use.
I attain these objects by the construction illustrated in the accompanying draw-
ing, in which Fig. 1 represents a top view of the scale; Fig. 2 is a side view
showing the arrangement of the different clamps and plates and Fig. 3 gives the
end view.
A modification of my invention is shown in Figs. 4, 5, 6, showing an auxiliary
sliding unit scale and special guide clamps, as will be hereinafter described.
In Fig. 7, I show a further modification of a duplex scale of novel construction.
Fig. 8 is the end view. Similar letters refer to similar parts through the several
views.
.
I build the scale ordinarily as shown in Fig. 1, which shows a structure where
a series of plates are united by the sliding clamps a, a, a. There is one cover
piece or plate 6 of flexible transparent material, then underneath this transparent
plate a stationary plate e containing the marks of the scale, leaving clearance enough
for the slide to move between these plates b and c. Sometimes I add another
transparent plate d between the slide and the stationary scale c, c. A transparent
plate e on the back of the stationary plate protects it against wear and tear e, e.
All of these plates are held together by the sliding clamps a, a.
These clamps
are preferably made of metal, and slide loosely on the transparent cover and reach
to the edges of the sliding scale. The ends are cut square, or the clamp is pro-
vided with a line n, m, so as to serve as index by either setting the edge of the
clamp or the mark to fix the figures on the scale. In this manner the clamps
serve to hold the whole structure together, and as a sliding index to fix the figures
on the scale.
Fig. 4 represents a modification where two plates f and g forming an auxiliary
scale are clamped to one of the transparent plates b. This plate 6 serves as a
guide when sliding the auxiliary scales, and its transparency allows a reading of
the main scale below. Some of the sliding clamps are formed with their ends bent
in between the plates, see Figs. 5 & 6, a¹, a¹, and keep the slide in place. In some
cases I prefer to use this arrangement when it is essential to keep the slides
steady.

page_text: Fig. 7 represents a duplex scale its parts being hinged together by means of the
sliding clamps. One rod m, passes for this purpose, through all the loops of the
clamps. This arrangement is of great use, as it combines a multiplicity of scales
in a very portable shape. Any of these slides may be shifted to serve as index.
The sliding scale as well as the stationary one may be arranged with any of the
well known scales. For instance; if the stationary scales as well as the sliding
scales were marked with the ordinary scale of inches, we could add 3 inches to
4 inches by setting 3 inches on slide to 0 inches, or to the beginning of the stationary
scale and then read above 4 inches on the stationary scale the answer 7 inches on
the slide, as is evident and often done by mechanics.
In the drawing illustrating my invention, I have shown the scale having the
exponents 2 or the upper scale divided with marks that the lengths 1-22, 1-3ª
and 1-43 and so on are proportional to the logarithms of 2, 3, 4 and so on, but of
double the length of the corresponding divisions of the other 3 scales, an arrange-
ment well known since 1624 as the Gunter scale.
If with these divisions of scales, 10 on the slide is set, as shown, on 8 of the
lower stationary scale, we find under 22 on the upper stationary scale the solution
of 5, viz, 5 on the upper scale on the slide.
If many examples of a similar kind are to be solved it is convenient to help the
memory by marking the number 8, by setting the mark on the sliding clamps on
its edge to 8.
To perform at the same time different operations, an auxiliary scale f, g, Figs. 4,
5, arranged with any of the well known divisions is ready to be used. It is, as
before described, attached to the transparent plate b with a clamp a¹, which allows
the slide f and stationary plate g to slide on the transparent plate 6 and also an
additional independent motion of the 2 plates. Also the slide of the main scale
can slide in any position underneath, and all the clamps holding the structure
of the main scales together can be moved to fix a number used in computation
by sliding these clamps in the proper position.
The system of division of the different plates is immaterial, as I do not claim
any particular division, as long as one plate slides on the other to perform the
operation.
I am aware that it has been common to make slide rules variously graduated
and marked, of two or more rigid sections, the main section having recesses in
which the subsidiary sections slide longitudinally; and I am also aware that it is
common to make rules or scales for engineers by printing the requisite numbers
and graduations and marks upon slips of paper or pasteboard.
The ordinary slide rules of rigid material are objectionable because they are
heavy; it is impossible to superpose a number of slides one upon the other. They
are rigid and cannot well be applied to curved surfaces, and both the rigid and
flexible rules are objectionable because when carried in the pocket they are apt
to become soiled so that it is extremely difficult to decipher the fine graduated
lines constituting the important features of their construction.
It will be seen that the construction of rules 'constituting the subject of this
application is not open to the objections to the slide rules heretofore made. Inas-
much as all of the sections are of thin flexible material, the rule can be applied
to curved surfaces as well as to flat surfaces, and what is more, the sliding rule
can thus be applied, while the sliding rules heretofore made have invariably been
rigid. Again, whether the rule is rigid or flexible, the transparent surface strips
serve to protect the graduated face of the rule from dirt and wear, so that the
operative condition of the article is preserved. Again, by means of the clamps
sliding upon the graduated faces, I am not only able to hold the superposed pieces
together, but I am also able to slide these clamps to different positions in respect
to the graduations so as to serve as marks or starting points or division points as
may be required. When a more complicated structure is required where there
must be a number of sliding strins connected with each other, the said slides may
be jointed together as before described, and at the same time may slide back and

page_text: forth confining the different portions or strips one to the other and at the same
time serving to mark a division or starting point upon the rule.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, I declare that what I
claim is:-
1. A rule having a main graduated body, one or more scales sliding thereon,
flexible transparent pieces extending over the other parts, and clamps holding all
the parts together and also sliding on the transparent covers, substantially as
described.
2. A rule having a main graduated flexible body, one or more flexible scales
sliding thereon, flexible transparent pieces extending over the other parts, and
clamps holding all the parts together and also sliding on the transparent covers,
substantially as described.
3. A rule having a main body, one or more scales sliding thereon, flexible trans-
parent pieces extending over the other parts, sliding clamps holding all the parts
together, and an auxiliary scale having one part sliding in respect to the other,
and a clamp holding the auxiliary scale to one of the flexible pieces, substantially
as described.
4. A scale consisting of separate series of graduated parts, each with trans-
parent flexible covers, and clamps sliding thereon, the said clamps of different
series jointed together but adapted to slide independently, substantially as
described.
Dated the 19th day of Oct 1807
BOULT & WADE,
Agents for the Applicant.