Improvements in Surface-gages.
Year: 1889

page_text: Date of Application, 2nd July, 1889-Accepted, 3rd Aug,, 1889
ADRALNICUTION
COME
Improvements in Surface-gages.
I, WILLIAM HENRY HARRISON NORCROSS of 49 Hammond Street Boston, County
of Suffolk, State of Massachusetts, United States of America, machinist, do hereby
declare the nature of my invention for IMPROVEMENTS IN "SURFACE GAGES" 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 instruments for testing the accuracy of plane-surfaces―
'surface gages," so called.
My invention relates to improvements in the construction of the gage as an entirety,
by which the needle may be moved readily, and thereby quickly adjusted; further, in
the particular manner of mounting said needle, which is reversible. Thus the
bilities of the instrument are increased in testing surfaces either in borizontal or vertical
planes.
сара-
The drawings represent in Figure 1 a vertical sectional elevation of a surface-gage
embodying my invention. Fig. 2 is a plan. Fig. 3 is an enlarged perspective view
of the clamping-screw.
In said drawings, A represents a solid metallic base of considerable weight, such that
the instrument will remain fixed and stationary while the hands of the operator are
employed in the adjustment of the needle. The latter (shown at B) consists of a
metallic bar, preferably of steel, enlarged in the middle portion, which is longitudinally
slotted at a.
This slot is to give the needle end wise movement to adapt it to advance
or retreat to reach different points of the work in process. The two ends b c are
differently constructed. The former, b, intended to test the accuracy of surfaces lying
in vertical planes, is straight. The latter, c, is bent at right angles and is adapted to
gage surfaces situated in horizontal planes.
The primary object of my invention is to provide both quick and fine adjustment,
by means of the first to rapidly and approximately adjust the needle to the work in
process, and by aid of the fine adjustment to set the needle accurately to any small
fraction of a linear unit, as may be desired.
To obtain the quick adjustment, I have secured upon the base a curved standard, C,
preferably in the arc of a circle, which is formed with an aperture, d, extending its
entire length. This standard, may, however, be made straight. Within this aperture or
slot is fitted a clamp-bolt, D, which is of peculiar construction and adapted for its
situation. Said bolt is composed of the head e and a shank, f, screw-threaded to
receive the clamping-nut g. The part h adjacent to the head is cylindrical to enable
the needle to rock thereon easily, after the bolt is fixed in position. Moreover, that
part i, which enters the aperture in the standard, is flattened upon one side. Thus
the semi-cylindrical portion just fits the aperture d, while the flat face prevents the
bolt from turning, and the latter can be moved easily upon the standard within the
slot. By this arrangement the needle can be turned easily upon said pivot-the
round part of the bolt. Further, the latter is prevented from turning, while the nut
can be screwed on or off without any trouble.
Generally in surface-gages the slow adjusting mechanism has been located at or
near the axis or center of movement provided for the quick adjustment, and the setting
of the needle cannot be so readily made. Hence in the present instance I have provided
a second standard or post, E, mounted in the block some distance from the standard ().
Said post is hollow and is adapted to receive a coiled spring, k, adjustable from below
by a screw. At the top and coincident with the center of said post is mounted an
adjusting-screw, m. Further I have formed a transverse aperture or slot, F, through
which passes the end of the needle opposite that secured upon the standard C. Thus
the action of the spring is to actuate the end of the needle which rests thereon, and as

page_text: the adjusting-screw is advanced or retracted this end of the needle is depressed or
raised, while the other end is moved oppositely but to a greater extent. By having the
needle supported at two points, there are several advantages gained. First, quick
adjustment in vertical planes is obtained by means of the slotted standard and its
locking-bolt, the needle being free to pivot upon the cylindrical portion of said bolt;
secondly, when in the act of moving the needle for the quick adjustment, the inactive
end of the needle is free to move end wise through its post E, as well as swing upon
its pivot-the extremities of the spring and the adjusting-screws; thirdly, by having
the fine adjusting mechanism at some distance from the axis of the quick adjustment
a small movement of that end desired to be adjusted is easily and readily effected.
The operation is as follows, the needle being arranged in the drawings for testing
surfaces in vertical planes: Should the operator desire to test a certain spot on work
in process, the clamping-bolt D is released by means of the nut g. This end of the
needle is now free and ready to be swung in a vertical plane rapidly and approximately
to the desired point, the needle now being centered or pivoted at the opposite end in
the post E between the spring and adjusting-screw.
Having set the end 6 of the needle approximately at the spot, the clamping-bolt is now
secured fast to the standard. This renders the forward pivot fixed upon the standard;
but owing to the construction of the bolt, which is cylindrical where the needle rests
upon it, said needle is free to swing thereupon for an axis. Such action now occurs
when the fine adjustment is made, which is effected by movement of the adjusting-
screw m. The latter, since the needle is now centered upon the clamping-bolt as a
pivot, has the advantage of the location some distance therefrom. Hence a very small
inovement is required to effect the desired fine adjustment.
One of the prominent features in my invention consists in providing the needle with
two pivots, while the center of movement may be shifted from one end of the needle
to the other, as either quick or fine adjustment is required.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. A surface-gage consisting of a base, two supports thereon, and a needle slotted
in part and upheld at two points by said supports, pivoting upon one for quick adjust-
ment, substantially as herein described.
2. A surface-gage composed of a base and two supports-a slotted standard and
.post-and a bar or needle upheld at two points and adapted to swing upon either
support as an axis in a vertical plane, substantially as and for purposes herein set
forth.
'
3. In combination with a suitable base, a curved slotted standard, and the needle
apertured in part pivoted thereto at one end, the hollow post with a transverse slot, in
which the needle is upheld and capable of adjustment in a vertical plane, swinging
upon a pivot, substantially as stated.
4. The reversible needle slotted in part, adjustable in a vertical plane, and having
end wise movement, two pivots, one at each end, combined with a slotted standard and
a clamping-bolt, a hollow post, with its adjusting screw and spring, and the base, all
operating as berein specified.
5. A suitable base, a hollow post transversely apertured, with the co-operating
spring and screw therein, a reversible needle-bar having end wise movement through
said post and oscillating upon it for one adjustment, combined with a standard, its
longitudinal slot, and the clamping-bolt engaging said needle, which swings upon said'
bolt for the other adjustment, substantially as herein stated.
Dated this Twentieth day of June 1889. at Boston. Mass.. U.S.A.
WILLIAM HENRY HARISON NORCROSS.