Improvements in Index Needles or Pointers for Electrical and other Indicating or Measuring Instruments.
Year: 1898

page_text: Date of Application, 22nd Mar., 1898-Accepted, 10th Dec., 1898
COMPLETE SPECIFICATION.
Improvements in Index Needles or Pointers for Electrical and other
Indicating or Measuring Instruments.
I, EDWARD WESTON, of No. 114, William Street, Newark, in the County of
Essex, and State of New Jersey, United States of America, Electrician, do hereby
declare the nature of this invention and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement:-
My invention relates to index needles or pointers for electrical and other indi-
cating or measuring instruments and has for its object; first to provide a novel
form of index needle or hand which shall be as light as possible second, to
provide a novel means of accurately counter-balancing said needle and all of
the movable parts so that it, the needle, will remain in definite positions under
all conditions of usage to which the instrument may be subjected; and third,
to provide a novel form of counter-balance or weight which may be adjusted
upon the needle to the desired point and will remain in such position after so
adjusted.
My said invention is illustrated in the accompanying drawing in which;
Figure 1 is a part plan part horizontal sectional view of my novel form of
index needle or hand, indicating also the manner of applying my novel counter
balances or weights thereon.
Figure 2 illustrates in enlarged sectional view my novel form of counter-
weight and the manner of applying the same to one of the radial counterbalancing
arms of the index needle or hand.
Figure 3 is a full sized plan view of a modified form of the index needle,
especially adapted for use with instruments of large current carrying capacity;
and
Figure 4 is an enlarged plan view of the pointer thereof showing in dotted
lines the means of attaching the same to the body part of the needle;
Figure 5 being a detail side elevational view of the same illustrating the like
parts as they are secured together.
Figure 6 is a transverse sectional view taken through the supporting part of
the needle illustrating the body part and principal counterbalancing arm in
elevational view; and
Figure 7 illustrates an enlarged plan view of the supporting part showing
the manner of constructing the same by stamping it from a thin sheet of
aluminium.
Referring now to Figures 1 and 2 for a description of the index needle and
its attached parts. d represents the entire needle which is constructed by strik-
out of a thin sheet of metal, preferably aluminium, a cross having arms A A
a a', the rectangular shaped opening being simultaneously struck out for
the purpose of constituting the support of the needle upon the instrument. The
body of the needle is composed of a drawn tube T of aluminium adapted to

page_text: have one end slipped over the arm A and secured thereto by a cement or by
pressure, the outer or index portion of the needle being flattened as shown at P
so that it will act as a retarding device as it moves through the air and also in
order that more delicate readings may be made upon the scale. The arms A¹a a¹
are all screw-threaded as shown and provided with counter-weights w w and W¹³,
the counterweights W being larger than the weights ww for the purpose of
balancing the tubular part T of the needle.
My novel form of counterweight is shown in detail in enlarged view in
Figure 2 of the drawing and is constructed by screw-threading interiorly one
end of a short tubular piece of metal and then slitting the same longitudinally
to a point approximating the other end thereof and finally squeezing the slitted
parts together so as to cause the screw-threads, when inserted in position upon
the arms a or a¹, to secure the counterweight to said screw threaded arms, the
free or unthreaded portion of the tube acting as a guide to enable one to place
it in position, it being a fact that where delicate counterweights of the nature
indicated are used great difficulty is experienced in assembling the parts unless
some guiding means be provided. This counterweight may, if preferred, be made
by making the interior screw-threaded end of less diameter than the interior
guiding end, in which event it would not be necessary to split it as described.
Referring now to Figures 3 to 7 inclusive which shows a modified form of the
index needle or hand, T represents the body part thereof which is constructed
preferably of a drawn tube of aluminium, P represents the pointer which is
constructed preferably by stamping it out of a very thin sheet of aluminium and
in the conformation shown with a central opening 01 and a raised bead U having
preferably the same contour as the outer contour of the pointer itself, the func-
tion of the raised bead being to give sufficient strength to the thin material to
cause it to maintain, under all conditions of usage, a rigid form.
E and E are thin flat lugs or ears at the inner end of the pointer which are
designed to be wrapped around the outer end of the body portion T as shown in
Figure 5, S being a flattened extension of the body portion adapted to have suffi-
cient bearing upon the under surface of the pointer to secure it permanently in
position, the parts being additionally secured together by any preferred form
of cement. C¹ represents the supporting part of the needle which is preferably
stamped out of a thin sheet of aluminium in such manner as to have four
radially disposed arms A A¹ and a a¹, the arms A and A' being preferably of
greater length and width than are the arms and a
H represents a rectangular opening in the supporting part for enabling the
needle to be sustained or supported upon the movable part of the instrument.
tt and t¹¹are holes or openings in the arms A and A¹ for securing respectively
the body part T of the needle and the principal screw-threaded counterbalancing
arm, made preferably of a light material such as aluminium.
ww are adjustable screw threaded counterweights for the arms a a¹ and Wis
a similar adjustable screw-threaded counterweight for the arm R¹, and wª is a
permanent counterweight secured to the outer end of the arm R¹, it together with
the arm R¹ being of sufficient weight to approximately counterbalance the weight
of the body part T and pointer P.
In assembling the parts of this needle, the arms a a¹ are first screw-threaded
as shown and the arms A and A¹ are bent first outward at points near the open-
ing H¹ and then again backward so that they are parallel with the supporting
part C¹ and their outer ends are then bent downward, all as shown clearly in
Figure 6.
The inner ends of the body part T and the principal counterbalancing arm R¹
are then bent at right angles and inserted respectively through the outer open-
ings and inner openings ft after which said ends are secured by rivetting as
shown at rr, and the arms A and A¹ are curved about the body part T and
principal counterbalancing arm R¹ in the manner shown in Figure 3. The
counterweights w w and Ware then secured in place upon their respective arms

page_text: and the permanent counterweight w² is permanently secured to the lower end of
the principal counterbalancing arm R¹.
The needle is now ready for use and may be secured to any instrument where
it is desired to apply it in the usual manner, after which it may be properly
counterbalanced through the agency of the counterbalancing weights w w, W₁ in
order to properly compensate for inequalities of weight in the movable parts of
the instrument itself.
Having now particularly described and ascertained the nature of my said in-
vention and in what manner the same is to be performed, I declare that what
I claim is;-
-
1. An index needle or hand consisting of a supporting part having radially dis-
posed arms and a central opening for securing the entire needle to the pivot
support of an instrument, in combination with a tubular body part secured to
one of said arms and counterweights adjustably secured to the other arms, sub-
stantially as described.
2. An index needle or hand consisting of a supporting part having a central
opening for securing it to the pivot support of an instrument, and a body part
secured to the supporting part, in combination with adjustable counterweights
so disposed with relation to the body part that the entire needle when secured
in place will remain stationary when the instrument is caused to assume different
positions, substantially as described.
3. An index needle or hand consisting of a supporting part, a body part and
two or more radially disposed arms provided with adjustable counterweights
adapted to effectually balance the needle and movable parts of the instrument
under all conditions of usage, substantially as described.
4. An index needle or hand provided with means for securing it to the movable
part thereof, and additional means radially disposed with relation to the axis
of the movable part in such manner as to effectually balance the needle and
moving part so that it, the needle, will remain in a fixed position when the
instrument itself is caused to asume different positions, substantially as described.
5. An index needle or hand consisting of a supporting part struck out of a
thin sheet of metal and having radially disposed arms and a central opening
for supporting the needle, in combination with a tubular pointer secured to one
of said arms and flattened at its free end, together with counterweights secured
to the remaining arms, substantially as described.
6. An index needle or hand consisting of a supporting part struck out of a
thin sheet of aluminium and having radially disposed arms and a central open-
ing for supporting the needle, in combination with a tubular pointer secured
to one of said arms and flattened at its free end, together with counterweights
secured to the remaining arms, substantially as described.
7. An index needle or hand consisting of a supporting part having three or
more radially disposed arms and a central opening for securing the needle to
the movable part of the instrument, one of said arms being adapted to secure
a tubular index hand, and the others being screw-threaded and provided with
correspondingly screw-threaded counterweights, substantially as described.
8. A counterweight for index needles or hands consisting of a short metallic
tube interiorly screw-threaded at one end, the opposite interior end thereof being
of greater diameter than the screw-threaded portion whereby it may act as a
guiding means for securing the counterweight upon the screw-threaded support,
substantially as described."
9. A counterweight for index needles or hands consisting of a short metallic
tube screw-threaded interiorly at one end and slitted longitudinally to a point
approximately the other end thereof, substantially as described.
10. A counterweight for index needles or hands consisting of a short metallic
tube screw-threaded interiorly at one end and slitted longitudinally to a point

page_text: approximately the other end thereof, said slitted part being afterwards squeezed
together, substantially as described.
11. An index needle or hand consisting of a supporting part having an open-
ing for securing it to the movable part of an instrument, and three or more
radially disposed arms upon one of which is secured a body part or pointer, the
remaining arms being screw-threaded, in combination with counterweights con-
sisting of short tubular pieces of metal each screw-threaded interiorly at one
end and slitted longitudinally in the direction of its length approximating the
other end thereof, said counterweights being secured in position upon the ends
of the radial arms in substantially the manner shown and described.
12. An index needle or hand consisting of a supporting part provided with
one or more counterweights and a body part having a flattened pointer provided
with a stiffening bead, substantially as described.
13. An index needle or hand having radially disposed arms adjustable counter-
weights therefor, in combination with a flattened pointer having a raised stiffen-
ing bead of substantially the same contour as the pointer itself, substantially as
described.
14. An index needle or hand having a pointer constructed from a thin sheet
of metal and provided with a raised stiffening bead, substantially as described.
15. A pointer for an index needle constructed of thin sheet metal, having
substantially the contour shown and a raised stiffening bead of substantially the
same contour.
16. An index needle or hand constructed of independent parts as follows, a
supporting part having radially disposed arms; a body part, a counterbalancing
arm for counterbalancing the body and a flattened pointer secured to the free
end of the body part together with counterweights, substantially as described.
17. An index needle or hand having a supporting part provided with radially
disposed arms, one of which supports a counterweight and the other the body
part proper, together with a pointer constructed from sheet metal and provided
with a stiffening bead, said pointer being secured to the free end of the body part,
substantially as described.
18. An index needle or hand constructed wholly of aluminium and consisting
of a supporting part having radially disposed armis, a body part and a thin flat
pointer having a strengthening bead, substantially as described.
19. An index needle or hand of aluminium consisting of a supporting part,
a body part and a pointer, said parts being secured together in substantially
the manner described.
20. An index needle or hand having a counter-balancing arm and a permanent
counterweight secured thereto, in combination with an adjustable counterweight
carried by said arm, substantially as described.
Dated this 28th day of October 1898.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.

page_text: Date of Application, 22nd Mar., 1898-Accepted, 3rd Dec., 1898
COMPLETE SPECIFICATION.
Improvements in Electrical Measuring Instruments.
I, EDWARD WESTON, of No. 114, William Street, Newark, in the County of
Essex, and State of New Jersey, United States of America, Electrician, do hereby
declare the nature of this invention and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement; —
My invention is directed to improvements in the well known type of electrical
measuring instruments in which a movable coil is pivotally supported by pivot
pins so as to vibrate back and forth in a curvilinear space formed between the
curvilinear poles of a permanent magnet and an intermediate stationary mag-
netizable cylinder, and its objects are;
First, to provide means for more accurately aligning the pivot pins which
support the movable parts of the instrument so that when in final position they
shall be located in the mathematical axis of the movable coil which they pivotally
sustain and that they may be readily renewed or replaced without disturbing
the pivot plates;
Second, to provide means for simplifying the adjustment between the spiral
springs attached respectively to the rotary or movable coil and fixed parts of
the instrument and also to afford better electrical conductivity between the ends
of the coil and said parts; Third, to so construct the rotary or movable coil
and its supporting frame or spool that it will move freely in the smallest avail-
able air space between the curvilinear pole pieces of the instrument and the
stationary magnetizable cylinder and that an increased magnetic flux will be
attained; Fourth, to so construct the stationary magnetizable cylinder that it
may be secured in place within the delicately constructed supporting frame or
spool which sustains the rotary or movable coil without touching it and that
it, the frame, will not be distorted during the assembling of the parts.
My invention will be fully understood by referring to the accompanying draw-
ings, in which,
Figure 1 illustrates a well known form of electrical measuring instrument
with my improvements attached thereto.
Figure 2 is an enlarged side elevational view of the movable coil and its sup-
porting frame or spool, together with my improved means for supporting and
accurately aligning the pivot pins and accurately adjusting the relations be-
tween the supporting frame, the oppositely disposed retractile springs and their
attachments to the rigid or fixed frame of the instrument.
Figure 3 is a detail transverse sectional view taken through the stationary
magnetizable cylinder, the ends of the curvilinear pole pieces being shown in
plan view.
Figure 4 is a detail sectional view similar to Figure 3, the pole pieces not,
however, being shown, said figure illustrating the manner of inserting the
stationary magnetizable cylinder in position without distorting the movable coil
and its supporting frame.

page_text: Figure 5 is a side elevational view of the end of a bar, preferably of aluminium,
illustrating the manner of constructing my novel form of pivot support.
Figure 6 is an end elevational view of the same as seen looking at Figure 5
from the top toward the bottom of the drawings; and
Referring now to the drawings in detail:-
M represents a horse-shoe magnet having curvilinear pole pieces B B' secured
thereto by screws C C, D being a non-magnetic bar secured to the ends of the
pole pieces by screws E E, said bar in turn sustaining, by screws F, a stationary
soft iron or magnetizable cylinder G. O is one of the bridges or supports for
the pivot jewels and is secured by screws, as shown, to the pole pieces B B¹
but insulated therefrom.
1 and 2 are the binding posts having the usual circuit
connections (not shown) through the movable coil of the instrument and the
spiral springs V V
Referring now to Figures 2 to 6 inclusive in which my present improvements
are illustrated in detail, and first to Figure 2; I represents a light non-mag-
netic frame of substantially rectangular form and of an interior curvilinear
structure closely approximating the curvature of the magnetizable cylinder G,
see Figure 4, said frame being made preferably of thin aluminium and adapted
to have wound thereon the rotary or movable coil H of insulated wire.
L and L are pivot supporting plates which are constructed by first placing
an aluminium bar or rod R, see Figure 5, in a turning lathe and turning off
the lateral edges thereof, as shown in Figure 6, then continuing the turning
operation until a standard is left; then turning off a still further portion, and
drilling a hole h so as to constitute a tubular standard p for the pivot pin K;
then advancing a double milling tool upon the opposite sides of the pivot sup-
port p so as to mill off the opposite faces at f f and furnish upon this pivot
support a substantially rectangular bearing for sustaining the index needle or
hand; then exteriorly screw-threading the standard p, as shown, and finally
cutting off the entire plate L by a cutting tool, on the line r Fig. 5. The
structure thus described constitutes the entire pivot plate for the upper end of
the coil H and its sustaining frame, the plate L¹ for the lower end of the coil
being a duplicate thereof, save that the milled faces f f are neglected. Pointed
pivot pins K and K are then accurately constructed and forced endwise by a tool
into position in the supports pas shown in Figure 2 of the drawings. The
plates L and L' are then secured to the opposite ends of the coil and its sup-
porting frame by any well known form of cement which will withstand such
heat as instruments of this nature are liable to encounter, it being understood
that the pivot supports and consequently the pivot pins are properly aligned in
the actual mathematical axis of the coll.
In Figures 3 and 4 I have illustrated how I diminish the air space between
the pole pieces and the magnetizable cylinder and also how I am enabled to
insert the latter within the close fitting or concentric surrounding frame I which
supports the rotary or movable coil H without distorting said parts, it being
obvious that where this cylinder approximates very closely to the inner diameter
of the frame there would be great danger of distorting the latter and its sus-
tained coil if some such means be not provided for permitting of its free inser-
tion. In order to properly effect this insertion, I cut a longitudinal groove gon
one side of the magnetizable cylinder G and opposite the screw-holes F1 which
receive the supporting screws F for supporting said magnetizable cylinder. The
supporting frame I is of substantially rectangular form and of curvilinear cross
section approximating the curvature of the pole pieces and magnetizable
cylinder G.
It will be apparent upon inspection of Figure 4 that when this magnetizable
cylinder is placed so that one edge of the supporting frame I rests in the groove g,
said cylinder may be rotated into position without touching the frame at any
point and after once in position within the curved space it may then be rotated

page_text: into the position shown in Figures 1 and 3 and properly secured to the non-
magnetic bar D) by the screws F see Figure 1.
Referring now to Figure 2, Z and Z represent rectangular metallic arms
having holes about the middle of their length for securing them to the pivot
supports and siits in their outer ends of such dimensions as to receive the
inner ends of the conducting coiled springs V and V, and n and n' are nuts
for permanently attaching said arms and the needle to the coil H after it, the
needle has been properly placed in position with its opening H about the faces ff
of the upper pivot plate L.
In assembling the parts after the pivot supports have been properly aligned
so that the pivot pins K and K' are in the mathematical axis of the coil and
the plates L L permanently cemented in position, the needle T is then put in
place upon the upper pivot plate L and the rectangular arms Z and Z are
slipped over the screw-threaded standards pp after which the nuts n and n¹ are
screwed thereon and the opposite ends of the coil H are soldered to the lower
lateral ends of the arms Z and Z. The spiral springs V V₁ are now placed in
position with their inner ends secured in the slits at the outer ends of the
arms and Z¹.
The magnetizable cylinder G is rolled into position within the frame I in
the manner shown in Figure 4 and rotated until the holes F1 F1 are in proper posi-
tion to permanently secure said cylinder. All of the movable parts, together with
the magnetizable core are now lowered into position between the field poles B B¹
and the screws F are secured in the magnetizable cylinder G.
The bridges 0 0 which support the pivot jewels for the pivot pins K and K'
are then placed in position and the parts secured together.
The spiral springs V and V are now adjusted with relation to the slots in
the stationary arms W at the opposite ends of the pole pieces B and B and the
counter-weights w w and W of the needle are adjusted so as to effectually
counterbalance the movable parts for all possible positions of the instrument.
The circuit connections are then effected from the binding posts 1 and 2, to
and through conductors not shewn, and in a manner obvious to those skilled in
the art of electrical measuring instruments.
Having now particularly described and ascertained the nature of this in-
vention and in what manner the same is to be performed, I declare that what
I claim is-
1. In an electrical measuring instrument provided with a movable coil, pivot
supporting plates having axially drilled holes, in combination with pivot pins
or bearings secured therein by forcing them endwise, substantially as described.
2. In an electrical measuring instrument provided with a movable coil, pivot
supporting plates having axially drilled holes in their outer ends and accurately
turned pivot pins or bearings forced therein, said supporting plates being secured
to the opposite ends of the coil with the pivot pins or bearings located in the
mathematical axis of the coil, substantially as described.
3. In an electrical measuring instrument provided with a movable coil, a pivot
supporting plate having an axially drilled hole in its outer end and a pivot pin
or bearing secured therein, the opposite sides of said plate being provided with
flat surfaces for the purpose of securing an index needle thereto, substantially
as described.
4. In an electrical measuring instrument provided with a movable coil, pivot
supporting plates secured thereto, in combination with metallic arms detachably
secured to said plates and soldered respectively to the opposite ends of the coil,
together with spiral springs and means for securing the same to the free ends
of the aforesaid arms, substantially as described.
5. In an electrical measuring instrument provided with a movable coil, pivot
supporting plates secured thereto, two rectangular metallic arms detachably
secured to said pivot plates by nuts and soldered respectively to the opposite ends

page_text: of the coil, the outer ends of said arms being provided with slits adapted to
receive the ends of spiral springs, substantially as described.
6. A pivot supporting plate for use in electrical measuring instruments con-
structed of a single piece of metal having a tubular standard screw-threaded
exteriorly, in combination with a pivot pin inserted in said standard and a
screw-threaded nut adapted to bind or hold in position the index hand of the
instrument and one of the conducting terminals of the coil to which said plate
is secured, substantially as described.
7. A pivot supporting plate for use in electrical measuring instruments having
a tubular standard exteriorly screw-threaded and flattened on its opposite sides for
The purpose of receiving an indicating hand or needle, in combination with ad-
justable means for securing one end of a spiral spring thereto, together with a
nut adapted to fit the screw-threaded portion of said standard and firmly secure
all of said parts together in a definite position with relation to the movable
parts of the instrument, substantially as described.
8. An electrical measuring instrument provided with pivot supporting plates
permanently secured to the movable part of the instrument in a definite position,
in combination with detachable or removable pivot pins secured to said plates,
substantially as described..
9. An electrical measuring instrument provided with a magnetizable cylinder
located within a substantially rectangular shaped movable coil closely approxi-
mating in diameter and curvature the cylinder, said cylinder having a groove
upon one side for admitting its insertion into the coil, substantially as described.
10. An electrical measuring instrument provided with a movable coil sup-
ported by a frame having curvilinear walls, in combination with a magnetizable
cylinder having a diameter closely approximating that of the frame, said cylinder
being provided with a groove on one side for permitting its insertion into the
frame, substantially as described.
11. An electrical measuring instrument having curvilinear pole pieces,
a stationary magnetizable cylinder located between said pole pieces and a mov-
able or rotary coil approximating in curvature the curvature of the pole pieces
and the cylinder, substantially as described.
Dated this 22nd day of March 1898.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.