Improvements in Micrometer Gauges and Callipers.
Year: 1893

page_text: Date of Application, 29th Mar., 1893
Complete Specification Left, 29th Dec., 1893-Accepted, 29th Mar., 1894
PROVISIONAL SPECIFICATION.
Improvements in Micrometer Gauges and Callipers.
I, JOHN CICERI SMITH of 219 High Street, Edinburgh, in the County of
Midlothian, North-Britain, Wire Cloth Manufacturer, do hereby declare the
nature of this invention to be as follows:-
This invention which relates to improvements in micrometer guages and
callipers, forms modifications of as well as additions to the instruments described
in the Complete Specification of Letters Patent granted to me on the 22nd October
1890 and No. 16,856.
The present invention has for one of its objects to so construct an instrument in
which the actual workmanship involved in its manufacture, or in which the actual
number of parts is reduced which require specially delicate adjustment, and, con-
sequently less high paid labour, so that the finished article would be produced
much cheaper, and at the same time would be as effective in regards to accuracy,
durability and utility. Another object is compactness in construction for con-
venience as a pocket guage or instrument. Another object is to increase the utility
and efficiency of the instrument by adding certain arrangements hereafter referred
to. In the event of any of these being added to any of the modifications said
addition will presumably increase ultimate cost. According to one arrangement of
carrying out my said invention, I proceed as follows, that is I cast or otherwise
form the main frame with a recess or hollowed out portion into which the mechanism
for counting is fitted by screwing or otherwise, or the mechanism may be carried in
an auxiliary thin frame which would be fitted into the said recess, the whole being
then covered by a thin sheet metal or other cover as hitherto. The said cover has
the necessary openings formed in one of its sides so as to enable the figures to be
read through. The index side of the frame may be fitted with a piece of glass to
exclude dust and at the same time allow the figures to be read through or magnified
by it. In this instrument the three counting wheels have their numbers preferrably
arranged around their peripheries in the following manner, that is the tenth wheel
has a circle of 10 figures, the hundredth wheel a circle of 10 figures and the
thousandth wheel having 20 figures, is twice the diameter of the two former wheels,
also if desired the screws thimble may have a circle of twenty equal divisions
around its front end which work in conjunction with a well known stationary
straight or angled line so as to enable the instrument to read tenths, hundredths,
thousandths and fractions of thousands; the micrometer screw having preferably
50 threads per inch, and the counter wheels may be actuated by any of the
mechanisms described in my said prior Specification, though preferably the well
known mechanism of a lug wheel engaging with a double wheel, one section having
full number of teeth the other section having only half the number, somewhat
similar to Fig. 21 of my former Patent. In this modification I largely accomplish
the object of compactness, as the first (or thousands) dial carries only ten figures
and its diameter is one half that of the other modifications which carries 20 figures.
Thus as no wheel or dial has more than ten figures, the external dimensions are
greatly reduced in more directions than one. Or I may make the three wheels of
equal diameter and provide the thousandth wheel with a circle of figures arranged
thus: 2, 4, 6, 8, 0, 2, 4, 6, 8, 0, and provide it with two pairs of lugs on opposite
sides of periphery for driving so as only to show five hundredths, the thousandths
being shown by the well known thimble of the screw. In either of the foregoing
cases the driving counter wheel is mounted on the screw or on a tube carried by
said screw or spindle, which has a pin fixed in it and which actuates the tube by

page_text: same gauge.
rotating and slides along freely in the compensating slot in said tube, as in former
Patent herein referred to, and if desired I may adjust the stop pin with a suitable
projecting face or faces preferably stationary to the extent of 001, more or less,
for gauging the limit or limits of sizes of a more or less large number of wires or
other articles, to be ganged by the instrument when the latter is used as a fixed
gauge, thus showing the variations of the several wires. All supposed to be nearly
In these modifications the mechanism runs preferably at right angles
to the micrometer screw, or spindle, and the dials, in place of rotating on the same
spindle, or centre, have independent centres. The half-leaf wheels are also mounted
with them on the same centres. By this means I am enabled to place the dials,
and wheels, about at a tangent to each other, and in an extended line, so that the
figures on the dials may be consequently read in a line, and as the dial wheels
engage directly with each other, I am enabled to obviate the necessity of any
intermediate wheels, or pinions, thus both reducing the back-lash between the
dials, and also the cost of manufacture. The instruments may also be so con-
structed as to have provision for compensating the instrument generally, against
expansion and contraction of the metals. For example, the screw might be made
in three parts of various metals according to the co-efficient of expansion or
contraction of the metals used; or the frame or casting might be composed of
various metals. In combination with my counting arrangements 1 may also employ
the well-known micrometer caliper square or foot-rule, consisting of the stationary
face fixed at right angles, and the sliding piece also at right angles. The latter
carries a short micrometer screw with my foresaid counting apparatus, and attached
to, and in conjunction with this, there is also an auxiliary sliding face which is
really the measuring face of the said caliper. This latter has a moving range of
preferably one tenth of an inch, and is actuated by the micrometer screw, which in
turn actuates the counting apparatus, thus registering all movements preferably
finer than one tenth of an inch. The foot rule is not ruled off in the ordinary way,
but carries a special arrangement of certain figures, which appear through extra
openings in the sliding piece, in such a manner that these figures appear in con-
junction, and in a line with, the figures registering on the counting apparatus.
The auxiliary slide has two tail pieces connected to each other by one or more
bars also to assist in preventing back lash. The two moving faces are actuated by
the screw having milled head, and the auxiliary face has the counter mounted in
it, while any tendency of the two faces to get out of position is effected by a spring
mounted between same in such a manner as to keep them extended from each
other, the thimble or milled head on the screw in this case may be provided with
ball bearings to prevent wear. The moving faces work or slide on the tail piece
of the stationary face which has two rows of figures and the main or front sliding
face has a pinching screw arrangement for binding same in any desired position,
also the auxiliary sliding face has a screw or spring or spring catch arrangement,
and two openings or holes for reading the figures on the tail piece.
The said instruments may also be applied to the French or metric measure as
well as the British standard. I may also add or combine with any of the
modifications, two or more seperate counters to be simultaneously actuated, by the
movement of the micrometer screw each producing different calculations or results
but, nevertheless having exactly or nearly the same equivalents.
For example, I might have one set of figures representing equivalent parts of
an inch, another equivalent parts of a millemetre another descriptive numbers of
British standard wire gauge, another the American descriptive numbers, and so on
according to requirements.
may add or combine any suitable electrical arrangement, for example, the
movement of the dials might be actuated by magnetic or electrical force, and the
mechanism suitably adjusted to give automatically the desired calculations, which
might greatly reduce the friction.
may add or combine with the frame, a yielding stop pin, in place of the ridged
stop pin, for the purpose of avoiding overstraining of the micrometer screw and

page_text: for obtaining a more delicate adjustment. This yielding stop pin will actuate a
needle or watch hand point or other indicator similar to those, which are well
known in combination with watchmakers micrometers, and are frequently used for
measuring fine hair springs or other articles, so that when the spring or other
article is gently drawn through between the points, it registers automatically all
the variations in the thickness of the said spring or article.
When the stop pin has no resistance the watch hand would spring back to
4 minus, but, when the article to be gauged is pressed by the screw against the
stop pin, the watch handle is gently brought up to zero and then the readings on
counter. are exactly correct, but, should the watch hand point to two or any other
figure plus, this must be added to the readings on counter and should it be minus,
then. deduct from the said readings.
Or I may add, combine or attach an arrangement, to be actuated by the yeilding
or other movement of the stop pin, in such a manner, as to have the effect of
almost instantly arresting the rotation of the micrometer screw, preferably when
the indicator or hand is pointing to zero. This may be effected either by a
mechanical or electrical arrangement or a combination of both.
I may also if desired, combine with any of the foregoing modifications, a light
spring arrangement in connection preferably with the 3rd dial in decimals, for
taking up backlash between the screw or other moving part of the micrometer
and the dials or counting wheels, the object being to impart an elasticity to the
gearing so as to reduce friction and so allow the instrument to work more
smoothly without impairing the accuracy of the readings. When the article to be
gauged is too heavy to be held to the instrument, the instrument may then be so
constructed that the readings be conveniently taken when the gauge is held to the
article.
Dated this 27th day of March 1893.
J. Y. JOHNSON,
115, St. Vincent Street. Glasgow, Petitioner's Agent.
COMPLETE SPECIFICATION.
Improvements in Micrometer Gauges and Callipers.
I, JOHN CICERI SMITH of 219 High Street, Edinburgh, in the County of
Midlothian, North Britain, Wire Cloth Manufacturer, 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 which relates to improvements in self calculating micrometer
gauges and callipers forms modifications of as well as additions to the instruments
described in the Complete Specification of Letters Patent granted to me on the
22nd October 1890-No. 16,856.
The present invention has for one of its objects to construct an instrument in
which the workmanship involved in its manufacture is reduced or in which the
number of parts requiring delicate adjustment is reduced and consequently less
high paid labor is required so that the finished article may be produced much
cheaper, and at the same time is as effective in regard to accuracy, durability and
utility. Another object is compactness in construction for convenience as a
pocket gauge or instrument. Another object is to increase the utility and
efficiency of the instrument by adding certain arrangements hereafter referred to.
In the event of any of these being added to any of the modifications, said
addition will presumably increase ultimate cost.
But in order that my present invention may be more readily understood and
easily carried into effect, I will describe the same with reference to the accom-
|panying drawings.
:

page_text: an emarged open elevation of the part of the gauge having the
counter attached.
Figures 2, 3, and 4 are sections taken on lines 1-1, 2-2, and 3-3, respectively
of Figure 1.
Figure 5 is an elevation of a gauge having its cover off and showing a
modification of the counting mechanism.
Figures 6 and 7 are sectional views on lines 4-4, and 5-5 of Figure 5.
Figure 8 is an elevation, showing a modification as adapted to show two sets of
figures simultaneously.
Figure 9 is an elevation, and Figures 10 and 11 detail views of another
modification.
Figures 12 and 13 are elevation and plan of a slide square or foot rule calliper
modification and
Figure 14 is a detail view of a modification.
According to one arrangement of carrying out my said invention I proceed as
shown, that is I cast or otherwise form the main frame A with a recess or hollowed
out portion a into which the mechanism for counting is placed and carried in an
auxiliary thin frame a¹ which is fitted into the said recess a the whole being then
covered by a thin sheet metal or other cover A' as hitherto. The said cover A'
has the necessary openings a² formed in one of its sides so as to enable the figures
of the counter to be read through. The index side of the frame may be fitted
with one or more pieces of glass as to exclude dust and at the same time allow the
figures to be read through, or the glass may such that the figures would be magnified
by it. In the instrument shown in Figures 1 to 4 the three counting wheels have
their numbers preferably arranged around their peripheries in the following
manner, that is the tenth wheel B has a circle of 10 figures, the hundreth
wheel C a circle of 10 figures and the thousandth wheel D having 20 figures is
twice the diameter of the two former wheels B and C, also if desired the screws
thimble may have a circle of 20 equal divisions E' and a circle of figures E²
arranged around its front end so as to work in conjunction with a stationary
straight or angled line E³ as described in my said prior Patent, and as is shown in
Figures 5 and 9, so as to enable the instrument to read tenths hundreths and
thousandths and if desired the drum of the screw may be provided with a vernier
scale so as to read fractions of thousands; the micrometer screw is preferably
formed with 50 threads to the inch and the counter wheels B, C and D may be
actuated by any of the mechanisms described in my said prior Specification, though
preferably the mechanism of the lug wheel engaging with the half leaf or double
wheel, one section having full number of teeth the other section having only half
the number somewhat similar to Figure 2 of my former Patent.
The counting or indicating mechanism runs at right angles to the micrometer
screw, or spindle and the dials B, C and D in place of rotating on the same spindle
or centre as hitherto, have independent centres as shown and the half leaf and lug
wheels are also mounted with them on the same centres. That is to say the dial D
which is mounted on the screw or spindle is provided with a spur wheel F which
communicates its motion to the spur pinion which is connected with the lug
wheel F and mounted on the spindle fi; said lug wheel F1 gearing with the half
leaf wheel F which is mounted on the same spindle as the dial C; said half leaf
wheel gearing into a spur wheel mounted on the spindle and connected to
the lug wheel F³, which gears with the half leaf wheel F', mounted on spindle f
of the dial B, in such a manner, as to represent tenths, hundreths and thousandths
of an inch.
In the modification shown in Figures 5, 6, and 7 the object of compactness is
greatly accomplished owing to the first (or thousands) dial D carrying only ten
figures, and as no wheel or dial has more than ten figures, the external dimensions
are greatly reduced in more directions than one. That is to say I make the thiee
wheels or dials B, C, and D of equal diameter and provide the thousandths wheel D,
with a circle of figures arranged thus 2, 4, 6, 8, 0, 2, 4, 6, 8, 0, and provide it with

page_text: two pair of lugs d, Figure 6, on opposite sides of periphery for driving, so as only
to show five hundreths, the thousandths being shown by the thimble E of the screw
as formerly. In either of the foregoing arrangements, the driving counter wheel D
is mounted on the screw or on a tube carried by said screw or spindle, which has a
pin fixed in it and which actuates the tube by rotating and slides along freely in
the compensating slot in the said tube as in my prior Patent. By this means I am
enabled to place the dials and wheels about at a tangent to each other and in an
extended line, so that the figures on the dials may be consequently read in a line,
and as the dial wheels engage directly with each other, I am enabled to obviate
the necessity of any intermediate wheels or pinions, thus both reducing the back-
lash between the dials and also the cost of manufacture.
I may adjust the stop pin with a suitable projecting face or faces, preferably
stationary to the extent of 001, more or less, for gauging the limit or limits of
sizes of a more or less large number of wires or other articles to be gauged by the
instrument, when the latter is used as a fixed gauge, for gauging articles supposed
to be the same gauge. That is to say, the screw spindle R, Figure 14, is adjusted
to the required position, and fixed in such position, by a pinching screw or other
suitable means so that the face of same is stationary. The stop pin S carries
two measuring faces 8, s¹ as shewn.
Suppose a quantity of wires require to be tested as to the gauge. Those which
pass the faces r, s, are too small. Those which do not pass between r, s', are too
large. Those which pass r, s', but do not pass r, s, are of the required gauge.
The instruments may be compensated against expansion and contraction of the
metals, by making the screw spindle in two, three or other number of parts, of
different metals according to the co-efficient of expansion or contraction of the
metals used; or by making the frame of different metals; all in the well known
manner of compensating instruments.
I may also add or combine with any of the modifications two or more separate
counters, as shown in Figure 8, to be simultaneously actuated by the movements
of the micrometer screw each producing different calculations or results, but
nevertheless baving exactly or nearly the same equivalents.
For example, I might have one set of figures representing equivalent parts of
an inch, another equivalent parts of a millimetre, another, descriptive numbers of
British standard wire gauge, another, the American descriptive numbers, and so on
according to requirements.
1 may add or combine with the frame A a yielding stop pin arrangement as
shown in Figures 9, 10 and 11 of the drawings, in place of the rigid stop pin
hitherto employed, for the purpose of avoiding overstraining of the micrometer
screw, and for obtaining a more delicate adjustment. This yeilding stop pin
arrangement consists of the moveable pin K which works in the slot k (Figure 11)
and is held in position by spring and actuated when the article to be gauged is
pressed against it by the contact of the micrometer screw spindle, in such a manner
that the sliding pin K actuates the needle or watch hand 1 (Figure 9) which is
held tight in position by the spring and indicates the measurements on the scale M.
in thousandths of an inch.
Between the frame A and the cover, I mount an adjusting plate N Figure 10
which is carried by the four screws as shown, and is held clear of the conical
pointed screw P by means of a projection of the frame A or suitable washers;
said conical pointed screw P being carried by frame A and working against the piní
or projection of the adjusting plate N in such a manner as to permit of the
plate N being longitudinally adjusted through the mechanism of the pins or
screw working in parallel guides or slots n' and the adjusting plate N is held tight
against the conical pointed screw P by means of a spring 3. The plate N carries the
watch hand L which is formed at its top end with a small pointer which is
actuated by sliding pin K through the medium of the pin or projection 2 in such a
manner that, the hand L and scale M register automatically all the variations in
the thickness of the article being gauged.

page_text: When the stop pin K has no resistance the watch hand L would spring back
to 4 minus, but when the article to be gauged is pressed by the screw against the
stop pin the watch hand L is gently brought up to zero and then the readings on
the counter are exactly correct, but should the watch hand L point two, or any
other figures plus, this must be added to the readings on counter and should it be
minus, then deduct from the said readings.
Or I may add, combine or attach an arrangement to be actuated by the yeilding
or other movement of the stop pin K in such a manner as to have the effect of
almost instantly arresting the rotation of the micrometer screw, preferably when
the indicator or hand is pointing to zero. This may be effected either by a
mechanical or electrical arrangement or a combination of both.
In combination with my counting arrangement, I may also employ a micrometer
calliper, square or foot rule as shown in Figures 12 and 13 consisting of a stationary
face G fixed at right angles and the sliding face or piece H also at right angles.
The latter piece H carries a short micrometer screw with my foresaid counting
apparatus, and attached to and in conjunction with this there is also an auxiliary
sliding face H' which is really the measuring face of the said calliper. This latter
face H' has a moving range of preferably one tenth of an inch and is actuated by
the micrometer screw which in turn actuates the counting apparatus, thus registering
all movements preferably finer than one tenth of an inch. The foot rule is not
ruled off in the ordinary way but carries a special arrangement of certain figures
which appear through extra openings in the sliding piece H in such a manner
that these figures appear in conjunction and in a line with, the figures registering on
the counting apparatus, thus enabling the readings to be easily taken. The two
moving faces H and H¹ are actuated by the screw having milled head and the
auxiliary face H has the counter mounted in it while any tendency of the two faces
to get out of position is affected by a spring mounted between the same in such
a manner as to keep them extended from each other, the thimble or milled head E
on the screw, in this case, may be provided with ball bearings to prevent wear.
The moving faces H and H' work or slide on the tail piece J of the stationary
face G which has two rows of figures and the main or front sliding face has a
pinching screw arrangement for binding same in any desirable position, also the
auxiliary sliding face H has a pinching screw arrangement or a spring or a
spring catch arrangement, and two openings or holes for reading the figures on
the tail piece J.
The said instruments may also be applied to the French or metric measure as
well as the British standard.
When the article to be gauged is too heavy to be held to the instrument, the
instrument may then be so constructed that the readings be conveniently taken
when the gauge is held to the article.
Having now particularly described and ascertained the nature of my inven-
tion and in what manner the same is to be performed, I declare that what I
claim is.-
1st. In micrometer gauges the arranging of counting mechanism within a
recessed portion of the main frame in such a manner that the dials are at right
angles to the screw or spindle and are driven therefrom by the first dial being
mounted on the screw or spindle, substantially as and for the purposes hereinbefore
described and shown in Figures 1, 2, 3, and 4 of the accompanying drawings.
2nd. In micrometer gauges the arrangement of the counting mechanism in a
recessed portion of the frame at right angles to the screw or spindle and driven
directly therefrom, substantially as and for the purposes here inbetore described and
shown more particularly in Figures 5, 6, and 7 of the accompanying drawings.
3rd. In micrometer gauges, arranging two or more counters side by side and at
right angles to the screw in such a manner that they are actuated simultaneously
and produce different calculations or results, substantially as hereinbefore described
and shown in Figure 8 of the accompanying drawings.

page_text: 4th. In micrometer gauges having counters the arrangement and combination
therewith of the moveable stop pin K adjusting plate N, and screw P parallel
guides n' and pins n or screws and tightening springs n³ substantially as and for
the purposes hereinbefore described and shown in Figures 9, 10 and 11 of the
accompanying drawings.
5th. The general arrangement construction and combination of the parts
constitution the slide rule calliper modification of a micrometer gauge, substantially
as herein before described and shown in Figures 12 and 13 of the accompanying
drawings.
Dated the 28th day of December 1893
JOHNSONS,
115, St. Vincent Street, Glasgow, Applicant's Agents.