AN IMPROVED APPARATUS FOR ASCERTAINING THE PARALLELISM OF TWO SURFACES FOR WORKING-ENGINEERS, FOREMEN, WORK INSPECTORS, ETC
Year: 1880

page_text: PROVISIONAL SPECIFICATION left by Giovanni Cucco at the Office of the
Commissioners of Patents on the 14th July 1880.
GIOVANNI CUCCO, of 22, Montague Place, Russell Square, London, W.C. "AN
IMPROVED APPARATUS FOR ASCERTAINING THE PARALLELISM OF TWO SURFACES
FOR WORKING-ENGINEERS, FOREMEN, WORK INSPECTORS, ETC."
a "screw,
To obtain speedly the true parallelism between the horn plates and wedges for
axle-boxes in locomotives, slide bars, steam hammers, sliding block guides, parallel
beams, etc., and in general between two surfaces whatever, I substitute iny
apparatus to the empirical means generally used to obtain the above purpose.
The annexed diagram to the present application completes this description. Let
M, N, rappresent two surfaces to be reduced parallel. I suppose M previously
reduced to a true surface by ordinary means, which M I tako as the base of
the operation; N is a rough surface yet and must be reduced parallel to M.
Fig. F (see dg.) is a tripod-foot, whose bottom part, as Fig. F¹ shows, is a very true
flat surface. Fig. Fo shows that this foot can receive into itself and keep steady
the spindle A, forining the central part of the gauge, terminated at one end with
3" long, and at the other end by a 3 axle that can play air tight in
a sliding piece B, which has a top T fixed by screw to it, and perforated by a
snifting passage for the air imprisoned in the variable space C. The central part of
the instrument shows a spring S, skilfully done, so to keep the sliding part B and
connected small parts in a state of tension little more than that of equilibrium
of its weight, so that when I slide the foot-gauge F¹ on M, the top T oscilates
very smoothly up and down, accordily it meets on N, points for more or less from
surface M. Spring S is surrounded by two small concentric brass alinding cylinders
t and t, whose duty is to transmit to B the power of S in a parallel direction with
the central axis of B, neutralising the action of dangerous bending frictions. The
groove m and screw pin m³ prevent B from having a twisting movement, and
from sliding beyond a certain limit, which in the present diagram is of inch. The
rod R participates of the movement of the top T, and communicates it to the
indicator I by mean of a small crank rigidly connected with I, and both C, I,
having a rotatory movement round the fulcrum O. The indicator I is 2" inches
and half long, namely ten times the crank C. The quadrant Q is divided in
8 compartments of unequal amplitude, but each of them corresponding to 16th of an
inch of the linear movement of the top T. Every compartment is in a very
D

page_text: visible way divided in 10 parts, which although of unequal amplitude (sec mathe-
matical calculation of the conversion of linear in circular movement) rapresent
cach Toth part of an inch of the linear movement of T. The compartments
8 and 7 being of considerable amplitude can have each division further subdivided,
namely, in the 8th compartment, in two to give the 10th part of an inch, and in
the 7th ditto each division can be subdivided in 10 parts to give the 100th part of
an inch. With the help of a common microscope it would be easy to obtain under
subdivisions of a very smaller dimensions. The nuts n, n³, conveniently used,
can limit the journey of T to the maximum and minimum distance of points on
N over M, giving a true criterion of the material to be removed in order to obtain
the parallelism. The same nuts can fasten top T with the spindle A, and they
can as well permit to it small novemnents. upwards or downwards. The scale on
the quadrant might be supplied by a paper, and the indicator I by a pencil, and we
could-have-traced on the paper the said maximum and minimum. The foot Fo can
be fixed with the part A by a pressure screw P, when by screwing or unscrewing
the part A into F, we adapted the general length of the gauge (from F¹ to T¹),
to the medium distance between M and N. This present model can safely work
from 9 to 12 inches, and a slight variation to the 3" inches scrow of A can enable
the gauge to work at a larger or smaller distances than 12" or 9″ respectively.