Improvements in Micrometer Calipers.
Year: 1899

page_text: PROVISIONAL SPECIFICATION.
Improvements in Micrometer Calipers.
We, FRANK SPALDING, of 175, Broadway, and EDWIN CHASE THURSTON, of
84, Oakland Avenue, both of Providence, in the County of Providence and State
of Rhode Island, United States of America, Mechanical Engineers, do hereby
declare the nature of this invention to be as follows:-
This invention has reference to an improvement in calipers for making micro-
metric measurements.
In micrometer calipers for measuring decimal fractions of an inch, as hereto-
fore constructed, the barrel was graduated by lines extending transversely from
a longitudinal or base line,--the longer of these transverse lines were one-tenth
of an inch apart and were marked by numerals; three shorter lines divided the
one-tenth inch-space into four parts. A sleeve secured to and turning with the
screw-threaded spindle formed the handle, and its forward, usually tapering,
end was graduated into twenty-five parts each line of which represented a
movement of the spindle equal to one one-thousandth of an inch. In reading
the micrometric fractions of these calipers, errors are frequently made because
the caliper does not indicate clearly the tenths, hundredths and thousandths of
the measurement.
Another difficulty with these calipers is that the sleeve, forming the handle
or hand-hold part which is usually provided with milled or otherwise roughened
periphery, is secured to the screw-threaded spindle and is liable to be turned in
handling the caliper, particularly in laying it down or taking it up.
One object of the invention is to provide a micrometer caliper of the conven-
tional form with a numerical index showing, in figures, the micrometric measure-
ment in tenths, hundredths and thousandths of an inch
or other units of
measurement.
Another object of the invention is to provide the micrometer caliper with
a handle inclosing the screw-spindle which does not turn with the screw-spindle
or on the barrel and does not affect the measurement.
To this end, the invention consists in the peculiar and novel construction of
the micrometer caliper whereby the resultant of the measurement is indicated
by decimal numerals, as will be more fully described hereinafter.
The improved calipers comprises the yoke which may be of the usual U-shaped
form. On one end of the yoke the anvil is secured and from the other end the
first index barrel extends; the barrel is internally screw-threaded and engages
with the screw-threaded portion of the spindle in the same manner as is usual
with micrometer calipers of this class. The spindle is provided with the annular-
flange, the cylindrical portion, the screw-threaded portion, the second cylindrical
portion, and the second screw-threaded portion at the end of the spindle. The
second index-barrel is secured to the spindle by clamping the annular-flange of
the barrel between the shoulder, formed by the annular-flange, and the lock-nut
in screw-thread engagement with the first screw-threaded portion so that the

page_text: index-barrel turns with the spindle. The sleeve which forms the handle or hand-
hold of the caliper, is, in form, like the sleeve heretofore used on this class of
calipers, cylindrical at the greater portion of its length and having a tapering
end; it is provided with the spline which enters the long.tndinal-groove on the
outer surface of the first barrel, so that while the sleeve can slide longitudinally
on the said barrel it cannot turn on the same. The third index-barrel is placed
between the first barrel and the sleeve and both the index-barrels closely fit and
are in frictional contact with the interior of the sleeve. The third index-barrel
is provided, on its outer surface, with the graduated, peripheral line of numerals
from 1 to 0 and again from 1 to 0 indicating, from 1 to 0 inclusive, ten figures
for each half of the circumference. One end of the third index-barrel is provided
with twenty small holes. The second index-barrel is graduated by forty lines
into forty spaces on its peripheral surface,-half, or twenty, of these lines are
longer than the twenty intermediate lines. Opposite each one of the longer lines
is a numeral of the line of numerals forming two consecutive sets of numbers
from 1 to 10, in the same manner as the numerals on the third index-barrel. A
hole extends, longitudinally, through the wall of the second index-barrel into
which the wire having a tapering end, is inserted, so that the tapering end may
enter any one of the holes at the end of the index-barrel; the wire is longer than
the second index-barrel; the end opposite the pointed end is slightly rounded
and the wire acts as a pawl by which the said second index-barrel is, from time
to time, connected with the third index-barrel so that the two may rotate together.
The cam-ring has, on its inner face, the two cams. The peripheral surface of
the cam-ring closely fits the interior of the sleeve and the bore of the cam-ring
forms a journal-bearing for the cylindrical portion of the spindle. The cam-
ring is secured to the sleeve by the screw; the screw-ring is screwed on the
screw-threaded portion to bear against the outer face of the cam-ring and the
peripherally milled-head is screwed on to bear against the screw-ring so as to
Jock each other firmly to the spindle. The sleeve is provided with a line, the
opening corresponding with the line of numerals on the second index-barrel, the
other opening corresponding with the line of numerals on the third index-barrel
and may be provided with the opening corresponding with the numerals on the
first barrel indicating the ten divisions of an inch, or other units of measurement,
placed to correspond with the ten transverse lines marked on the said first barrel
one-tenth of an inch apart. The three shorter lines, heretofore used to divide
each tenth into four parts, are omitted but, if desired, they may be used.'
To enable others skilled in the art to use our invention, we will now more
fully describe the operation of our micrometer index-caliper. The spindle having
been withdrawn from the anvil by turning the same by means of the head to the
left, the distance between the anvil and the end of the spindle is one-tenth of
an inch. The end of the sleeve is on the transverse line on the first barrel
marked by the numeral and one of the long lines on the second index-barrel is
opposite the line on the sleeve. The reading of the index of the caliper
is 1-0-0, indicating that the measurement is one one-hundred thousandth of
an inch. By turning the head, and thereby the spindle toward the left until
the next line on the second index-barrel (which is a short line) is on line with
the line on the sleeve the caliper will show, on the index, the numerals 1-0
on the openings but will show the numerals 0 and 1 below and above the line on
the sleeve and the reading of the index will be 1–0–0 plus of a thousandth
indicating the measurement to be one one hundred and five ten-thousandths
of an inch.
As the second index-barrel turns with the spindle and the cam-ring secured to the
sleeve, remains stationary, the rounded end of the wire projecting from the end
of the said index-barrel adjoining the cam-ring encounters the cam and is moved
longitudinally by the incline on the cam so that the pointed end of the wire
enters one of the holes in the end of the third index-barrel and the two index-
barrels will move together while the numeral 1 or 9 of the second index-barrel

page_text: is moving away from the line on the sleeve thereby exposing the next numeral
on the third index-barrel in the opening adding or subtracting as the two index-
barrels are moved to the right or to the left. The swell on the cams is equal
to the distance between two of the long lines on the second index-barrel and
holds the wire in engagement in one of the holes. The instant the rounded-head
of the wire passes the surface of the cam the conical, pointed end, acting on the
periphery of the hole pushes the wire out of the hole and disconnects the third
index-barrel from the second index-barrel after turning the same one space and
exposing the next adjoining numeral at the opening in the sleeve. For each
ten numerals successively exposed at the opening the third index-barrel is moved
one numeral and for each ten successive numerals exposed at the opening the
end of the sleeve moves longitudinally on the first barrel one-tenth of an inch
and either covers or exposes the next numeral.
The particular detail construction for securing the second index-barrel to the
spindle and the mechanism for automatically moving the third index-barrel one
space at predetermined intervals, herein described, perform the required func
tions, but we do not wish to confine ourselves to the exact construction of these
and other parts as they may be varied without materially affecting the essential
features of our invention by which we supply a micrometer caliper with a non-
rotatable sleeve forming a secure handle and having openings exposing numerals
indicating the measurement.
1
T
1000
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., .
Agents for the Applicants.
Improvements in Micrometer Calipers.
We, FRANK SPALDING, of 175, Broadway, and EDWIN CHASE THURSTON, of
84, Oakland Avenue, both of Providence, in the County of Providence and State
of Rhode Island, United States of America, Mechanical Engineers, 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 has reference to an improvement in calipers for making micro-
metric measurements.
In micrometer calipers for measuring decimal fractions of an inch, as hereto-
fore constructed, the barrel was graduated by lines extending transversely from
a longitudinal or base line, the longer of these transverse lines were one-tenth
of an inch apart and were marked by numerals; three shorter. lines divided the
one-tenth inch-space into four parts. A sleeve secured to and turning. with the
screw-threaded spindle formed the handle, and its forward, usually tapering, end
was graduated into twenty-five parts each line of which represented a movement
of the spindle equal to one one-thousandth of an inch.
In reading the micrometric fractions of these calipers, errors are frequently
made because the caliper does not indicate clearly the tenths, hundredths and
thousandths of the measurement.
Another difficulty with these calipers is that the sleeve, forming the handle
or hand-hold part which is usually provided with milled or otherwise roughened

page_text: periphery, is secured to the screw-threaded spindle and is liable to be turned in
handling the caliper, particularly in laying it down or taking it up.
One object of the invention is to provide a micrometer caliper of the con-
ventional form with a numerical index showing, in figures, the micrometric
measurement in tenths, hundredths and thousandths of an inch or other units
of measurement.
Another object of the invention is to provide the micrometer caliper with a
handle inclosing the screw-spindle which does not turn with the screw-spindle or
on the barrel and does not affect the measurement.
To this end, the invention consists in the peculiar and novel construction of
the micrometer caliper whereby the resultant of the measurement is indicated
by decimal numerals, as will be more fully described hereinafter.
Figure 1 is a side view of our improved micrometer caliper.
Figure 2 is a longitudinal sectional view of the handle portion of the same.
Figure 3 is a side view of one of the index-barrels and Figure 4 is an end
view of the same.
Figure 5 is a side view of another index-barrel and Figure 6 is an end view
of the same.
Figure 7 is a side view of the cam-ring and Figure 8 is an end view of the
Bame.
Figure 9 is a side view of a lock-nut and Figure 10 is an end view of the
same.
C
Similar reference-marks indicate corresponding parts in all the figures.
In the drawings a indicates the yoke which is shown in Figure 1 in the usual
U-shaped form. On one end of the yoke the anvil is secured and from the other
end the barrel e extends; the barrel is internally screw-threaded and engages
with the screw-threaded portion of the spindle d in the same manner as is usual
with micrometer calipers of this class. The spindle d is provided with the
annular-flanged, the cylindrical portion d², the screw-threaded portion ³, the
cylindrical portion d and the screw-threaded portion at the end of the spindle.
The index-barrel e is secured to the spindle by clamping the annular-flange el of
the barrel between the shoulder, formed by the annular-flange d, and the lock-
nute, in screw-thread engagement with the screw-threaded portion so that
the index-barrel e turns with the spindle d. The sleeve f, which forms the
handle or hand-hold of the caliper, is, in form, like the sleeve heretofore used on
this class of calipers, cylindrical at the greater portion of its length and having
the tapering end f¹; it is provided with the spline 2, which enters the longi-
tudinal-groove e¹ on the outer surface of the barrel c, so that while the sleeve f
can slide longitudinally on the barrel c it can not turn on the same. The index-
barrel is placed between the barrel c and the sleeve f and both the index-
barrels and g closely fit and are in frictional contact with the interior of the
sleeve f. The index-barrel g is provided, on its outer surface, with the graduated,
peripheral line of numerals g¹ from 1 to 0 and again from 1 to 0 indicating,
from 1 to 0 inclusive. ten figures for each half of the circumference. One end
of the index-barrel g is provided with twenty small holes 3. The index-barrel e
is graduated by forty lines into forty spaces on its peripheral surface,-half,
or twenty, of these lines are longer than the twenty intermediate lines. Opposite
each one of the longer lines is a numeral of the line of numerals forming two
consecutive sets of numbers from 1 to 10, represented by 0, in the same manner
as the numerals on the index-barrel g. A hole extends, longitudinally, through
the wall of the index-barrel e into which the wire e, having a taper-
ing end, is inserted, so that the tapering end may enter any one of the holes g³
at the end of the index-barrel g; the wire e is longer than the index-barrel e:
the end opposite the pointed end is slightly rounded and the wire acts as a pawl
by which the index-barrel e is, from time to time, connected with the index-
barrel so that the two may rotate together.
The cam-ring h, shown in Figures 7 and 8, has, on its inner face, the two

page_text: cams h¹-h¹. The peripheral surface of the cam-ring closely fits the interior of
the sleeve and the bore 2 of the cam-ring forms a journal-bearing for the
cylindrical portion of the spindle d. The cam-ring his secured to the sleeve f
by the screw h3; the screw-ring is screwed on the screw-threaded portion d to
bear against the outer face of the cam-ring hand the peripherally milled-head
is screwed on to bear against the screw-ring i so as to lock each other firmly to
the spindle d. The sleeve is provided with the line 3, the opening ft corre-
sponding with the line of numerals et on the index barrel e, the opening f
corresponding with the line of numerals g¹ on the index-barrel g and may be
provided with the opening fo corresponding with the numerals on the barrel c
indicating the ten divisions of an inch, or other units of measurement, placed
to correspond with the ten transverse lines marked on the barrel cone-tenth of
an inch apart the zero line of which is shown in Figure 1. The three shorter
lines, heretofore used to divide each tenth into four parts, are omitted but, if
desired, they may be used.
To enable others skilled in the art to use our invention, we will now more
fully describe the operation of our micrometer index-caliper. In Figure 1, the
spindle has been withdrawn from the anvil by turning the same by means of
the head to the left, the distance between the anvil b and the end of the
spindle d is one-tenth of an inch. The end of the sleeve f is on the transverse
line on the barrel c marked by the numeral 1 and one of the long lines on the
index-barrel e is opposite the line 3 on the sleeve f. The reading of the index
of the caliper is 1-0-0, indicating that the measurement is one hundred
thousandths of an inch. By turning the head k, and thereby the spindle d,
toward the left until the next line on the index-barrel e (which is a short fine)
is on line with the line 3 on the sleeve f the caliper will show, on the index the
numerals 1-0 on the openings f and fo but will show the numerals 0 and 1
below and above the line f³ on the sleeve f and the reading of the index will
be 1-0-0 plus ½ of a thousandth indicating the measurement to be one
hundred thousandths and five ten thousandths of an inch.
As the index-barrel e turns with the spindle d and the cam-ring h, secured to
the sleeve remains stationary, the rounded end of the wire es, projecting from
the end of the index-barrel e adjoining the cam-ring h, encounters the cam h¹
and is moved longitudinally by the incline on the cam so that the pointed end
of the wire e enters one of the holes g³ in the end of the index-barrel g and the
two index barrels will move together while the numeral 1 or 9 of the index-barrel e
is moving away from the line f³ on the sleeve f, thereby exposing the next
numeral on the index-barrel g in the opening f adding or subtracting as the
two index-barrels are moved to the right or to the left. The dwell on the cams h¹
is equal to the distance between two of the long lines e³ on the index-barrel e and
holds the wire e in engagement in one of the holes g³. The instant the rounded-
head of the wire e passes the surface of the cam h¹, the conical, pointed end,
acting on the periphery of the hole g³, pushes the wire out of the hole and dis-
connects the index-barrel from the index-barrel e after turning the same one
space and exposing the next adjoining numeral at the opening f5 in the sleeve f.
For each ten numerals successively exposed at the opening f, the index-barrel g
is moved one numeral and for each ten successive numerals exposed at the open-
ing the end of the sleeve f moves longitudinally on the barrel c one-tenth of
an inch and either covers or exposes the next numeral.
The particular detail construction for securing the index-barrel e to the
spindle d and the mechanism for automatically moving the index-barrel gone
space at predetermined intervals, herein described, perform the required func-
tions, but we do not wish to confine ourselves to the exact construction of these
and other parts as they may be varied without materially affecting the essential
features of our invention by which we supply a micrometer caliper with a non-
rotatable sleeve forming a secure handle and having openings exposing numerals
indicating the measurement.

page_text: Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed, we declare that what
we claim is:-
Claim 1. In a micrometer caliper, the combination with the internally screw-
threaded barrel, a spindle in screw-thread engagement with the internal screw-
thread of the barrel and a head on the spindle for turning the same, of a sleeve
connected with the barrel, held against rotation on the same and journaled on
the spindle to move longitudinally with the spindle, index-barrels within the
sleeve rotated by the spindle, and one or more openings in the sleeve; whereby
the position of the spindle is indicated by the numerals exposed, as described.
2. In a micrometer caliper, in combination, a screw-threaded spindle, a head
at one end of the spindle for turning the same, a barrel extending from the
frame of the caliper and in screw-thread engagement with the screw-threaded
spindle, index-barrels, external to the barrel, extending from the frame, a sleeve
having a recess for the index-barrels and one or more openings, and connections
between the index-barrels and the spindle; whereby the sleeve and index-barrels
move longitudinally with the spindle and the longitudinal position of the spindle
is indicated by numerals, as described.
3. In a caliper, the combination with the externally-graduated and internally
screw-threaded barrel and the screw-threaded spindle, of a sleeve connected with
the barrel and with the spindle, whereby the sleeve, while moving longitudinally
with the spindle, is held against rotation and may be used as a convenient handle,
as by it the position of the spindle can not be changed.
4. In a micrometer caliper, the combination of the following instrumen-
talities: the frame of the caliper, a barrel extending from the frame, a spindle
in screw-thread engagement with a fixed part of the frame, or barrel, a sleeve,
external to the barrel, connected with the spindle so as to move longitudinally
with the same, one or more index-openings in the sleeve, index-barrels rotatable
independent of and moving longitudinally within the sleeve, and means for
rotating one of the index-barrels, at. predetermined intervals, with the other;
whereby the measurement of the caliper is indicated at the index-opening in
the sleeve, as described.
5. An index micrometer caliper consisting of the usual spindle in screw-thread
engagement with a fixed part of the frame, one or more cylindrical index-barrels
having numerals on their peripheral surface and a perforated sleeve connected
with and moving longitudinally with the spindle and inclosing the index-
barrels whereby numerals indicating the measurement are exposed to view, as
described.
6. An index micrometer caliper consisting of the usual spindle in screw-thread
engagement with a fixed part of the frame, one or more cylindrical index-barrels
having numerals on their peripheral surface, a non-rotatable, perforated sleeve
forming the end bearing of and inclosing the index-barrels and connections
between the spindle and one index-barrel; whereby the index-barrel is rotated
by and moves longitudinally with the spindle and the numerals are exposed to
indicate the measurement, as described.
7. The combination with the frame of a micrometer caliper and the internally
screw-threaded barrel extending from the frame, of the spindle d having the
operating-head secured to one end thereof, the index-barrel e rigidly secured to
the spindle and provided with the pointed-wire e6, the index-barrel having the
series of holes g³, the cam-ring h journaled on the spindle d, the sleeve f con-
nected with the barrel and held against rotation, graduations and numerals on the
barrel dividing the units of measurement into ten parts, the numerals on the
index-barrels and an opening, or openings, in the wall of the sleeve f; whereby
the rotation of the spindle exposes numerals, to view indicating the measurement,
as described.
8. In a micrometer caliper, the combination with the frame and the internally

page_text: screw-threaded barrel, of the screw-threaded spindle d having the annular-
flanged, the screw-threaded portion d³, the cylindrical-portion d' and the
screw-threaded end d³, the head secured to the end of the spindle, the index-
barrel e secured to the spindle by the nut e, the pointed wire in the wall of the
index-barrel e, the index-barrel g, the holes ³ in the end of the same, the sleeve f,
the cam-ring journaled on the spindle d and secured to the sleeve f, the two
cams on the cam-ring, the graduation on the internally screw-threaded
barrel, the numerals on the index-barrels and an opening, or openings, in the
side of the sleeve f; whereby the sleeve, held against rotation, moves longi-
tudinally with the spindle and exposes the numerals indicating the measurement,
as described.
9. In a micrometer caliper, the combination with the usual internally screw-
threaded barrel graduated on its external surface by transverse lines into ten
equal parts of a unit of measurement and the usual leading screw-spindle, of a
sleeve perforated with the openings f and f5, the index-barrels e and g within
and moving longitudinally with the sleeve each having a line of figures con-
sisting of twenty numerals, and means, substantially as described, for operating
the index-barrels; whereby, when the spindle is turned in either direction
numerals indicating the position of the end of the spindle with reference to the
anvil are exposed to view in the openings of the sleeve, as described.
10. In combination with the usual frame of a micrometer caliper, the
externally-graduated and internally screw-threaded barrel and the usual screw-
threaded leading spindle, of the perforated sleeve f connected with the spindle
so as to move longitudinally with the same, the index-barrel y, the two series of
numerals from 0 to 9 each on the peripheral surface of the same, the index-
barrel e, the two series of numerals from 0 to 9 each on the peripheral surface of
the same, the lines on the peripheral surface of the index-barrel e dividing
the periphery into forty parts by alternately long and short lines, and a con-
necting-mechanism; whereby, at predetermined intervals, the index-barrel e
moves the index-barrel through a fixed distance and numerals indicating the
decimals, the result of the measurement, are exposed at the opening, or openings,
in the sleeve, as described.
FRANK SPALDING.
EDWIN CHASE THURSTON.
Haseltine, Lake & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicants.