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Патент USA US2125257

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Juìy 26, 1938.
O. s. Fil-:LD
2,lZ5,257
LIGHT SIGNAL FOR RAILROADS
Filed Feb. 2l, 1935
2 Sheets-Shea?l 1
Flai.
1
l
INVENTOR
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¿E
32
¿i
Á
BY
-
ATTORNÉY
I
July 26, 1938„
o. s. FIELD
2,125,257
LIGHT SIGNAL FOR RAILROADS
Filed Feb. 21, 1935
2 sheets-sheet 2
Fla@
E
ÉINVENTOR
~
BY @5 Wd
Patented July 2_6, 1938Vv
2,125,257
i UNTTED STATES
PATENT OFFICE
2,125,257
LIGHT SIGNAL FOR RAILROADS
Oscar S. Field, Rochester, N. Y., assigner to Gen
eral Railway Signal Company, Rochester, N. Y.
Application February 21, 1935, SerialNo. 7,565
5 Claims. (Cl. 175-339)
This invention relates to color light signals for
railroads, and more particularly to improvements
in the motor devices for such a signal of the so
called search light type which employs a movable
5
color screen.
In one type of color light signal commonly
used on railroads, such as disclosed in my prior
Patent No. 1,835,150, December 8, 1931, a three
position motor device is employed to move a spec
10 tacle or color screen to any one of three dif
ferent positions so as to display the desired color
indication. It is desirable that such a motor
device should be efficient and yet provide sub
stantial operating forces with relatively small
currents to actuate contacts and overcome bias
ing counterweights; and at the same time this
motor device should have such size and rigidity
of parts, large clearances and the like, as to be
highly reliable in its operation, and particularly
free of the possibility of sticking by any derange
ment of parts or the eifect of continued use.
Among other things, it has been found expedi
ent to mount the shaft of such a three-position
motor device or knife-edge bearings to have a
25
minimum amount of friction and tendency to
stick in use.
likewise, it is desirable to have a
relatively high ratio of the drop-away current
to the normal operating current.
With these and other considerations in mind,
it
is proposed in accordance with this invention
30
to improve the ñeld and armature structure of
Considering ñrst the general organization of
the type of signal with which my improved motor
deviceV is used, the preferred construction is il
lustrated and described in my prior Patent No.
1,835,150, and also in my prior application above
mentioned; and this preferred organization in
general comprises a lamp I 'with a concentrated
filament, a reflector 2, and a sector shape spec
tacle frame or color screen 3 disposed near the
focal point of the reflector and movable to inter
pose green, yellow, or red color glasses in the
light beam',y projected through the lens 4 at the
front of the signal. The primary purpose of the
motor device of this invention is to move the
spectacle or color screen 3 from an intermediate
position to which it is biased by suitable counter
Weights, to either of two extreme positions, and
also to actuate contacts in such extreme positions.
The motor device comprises a shaft 5 of suit
able magnetic steel with axial bores in the ends 20
in which are pressed and secured spindles B of
hardened steel. The end portions of the arma
ture shaft 5 are shouldered and threaded; and
two armature Wings or vanes 'l and 8 of a general
sector shape, as best shown in Fig. 3, are clamped
to the ends of the shaft by nuts 9 on said 25
threaded portions. The armature vanes l and
8 extend radially froml the shaft 5 in opposite
directions, the vane 1 in the front as viewed in
tioned, and also my prior application, Ser. No.
470,056, filed July 23, 1930, now Patent No.
2,097,785 dated November 2, 1937 so that the
forces reacting upon the shaft upon the applica
tion of turning torque will tend to maintain the
Fig. 3 extending downward, and the other vane
8 in the rear extending upward. The color screen 30
3, with the three colored glasses or mountings
G, Y, or R therein, is fastened to the armature
vane 8 (see Fig. 2). The armature shaft is sup
ported on knife-edge bearings; and in the pre
ferred construction, the spindles 6 are formed 35
with recesses and supported on hardened knife
edges I0, together with a ball thrust bearing, in
shaft at both ends in contact with the knife
the manner disclosed more in detail in the pat
such a motor device, more particularly of the
type disclosed in my prior patent above men
40 edge bearings, and further so that an increased
torque by direct magnetic attraction will be effec
tive near the extremes of the movement of the
shaft where a greater operating force is desirable
to provide adequate Contact pressure.
Various other characteristic features, attributes
and advantages of the invention will be in part
apparent and in part explained as the descrip
tion progresses.
In the accompanying drawings, Fig. l shows
Ul O generally the organization of a color light signal
embodying my improvements, this figure showing
a vertical longitudinal section through the motor
device; Fig. 2 is a transverse section through the
motor device substantially on the line 2_2 of
mi DI Fig. 1; Fig. 3 is a diagrammatic perspective of the
more essential parts of the field and armature
structure; Fig. 4 is a fragmentary edge view of
one of the pole pieces; and Fig. 5 is an explana
tory diagrammatic view of counterweight and
contact operating mechanism.
ent to J. L. Osborne, No. 1,785,702, December 16,
40
1930.
In the preferred construction, the armature
shaft 5 is surrounded by a copper sleeve l2 at
tached thereto; and around this sleeve with a
relatively large clearance, is another copper sleeve
I3 on which is wound the armature coil or wind
ing lil. This armature coil
is surrounded by
a split sleeve cover I5, preferably of suitably in
sulated material, which is supported by the main
frame of the signal.
The armature shaft 5 and vanes l and 8 are '
biased to an intermediate position shown in Fig.
3 by two counterweights I6 pivoted at Il as shown
in Fig. 5.
A counter-balancing member I8 in the form of 55
a casting of substantially the same contour as
that of the armature vane 1 is secured thereto
by rivets or the like; and the distribution of
weight in this member I8 is varied by borings in
accordance with common practice so as to coun
60
2
terbalance
’2,125,257
accurately the color screen or spec
ample, such component acting on the front Vane
‘l as viewed in Fig. 3 and indicated by the arrow
a tends to pull down the front end of the shaft
tacle 3. At the upper edge of this member I8 is
a curved flange I9, to which two links 20 are
pivotally connected at their upper ends; and the
lower ends of these links are slotted and engage
with pins 2i ñxed in the two counterweights
I8. A block of suitable insulating material is
ñxed to the end of each counterweight I6; and>
to this block is fixed a spring contact member 22
proved arrangement constituting this invention,
so arrangedV as to engage stationary contacts 23
in the two extreme positions of the counter
the armature vanes 'I and 8 are disposed so that
the forces of attraction acting thereon and ex
weight, with the appropriate contact pressure.
It will be evident that when the armature shaft
erting a tendency to tilt the armature shaft 5
transversely of its axis are in opposition, rather
than cumulative as in my prior Patent No.
5 is turned in one direction, say clock-wise as
viewed in Fig. 5, the left-hand counterweight i6
is raised by the link 26 and the left-hand con
tact ñnger 22 is shifted. Suitable adjustable
stop screws 2li and 25 limit the upward and
downward movement of each counterweight I6.
The field structure of the motor device com
prises two plates 21 and 28 of magnetic material
of a general U-shape with their side portions
shaped as shown in Fig. 3 to form curved pole
pieces 2171 and 281. These plates 2ï and 28 are
25 supported in the signals by bolts 29 (the ends
of which appear in Fig. 1), passing through holes
30 in said pole pieces. The two U-shaped field
core members 2ï and 28 are connected at the
5 against its knife-edge bearing, and the similar
component acting on the rear armature vane 8
and indicated by the arrow b tends to push down
the rear end of the shaft against its bearing.
In other words, in accordance with the im
1,835,150, with the result that the tendency to
lift the armature shaft oif of its knife-edge bear
ing at either end is greatly reduced, if not en
tirely eliminated.
. In this connection, it is evident that variations
in the air-gap between the armature vanes and
their co-operating pole pieces, together with
changes in the flux distribution and the relative
dimensions of the parts, will affect the relative
intensity and direction of the forces of magnetic
attraction acting on the armature vanes, so that
in structures manufactured on a commercial
basis the components tending to tilt the arma
ture shaft may not be exactly balanced and
bottom by four permanent bar magnets 3i, ar
30 ranged in pairs with spacers supported by clips
32 and clamped by a through bolt 33.
So far described, the structure and assembly
than the weight of the armature element; but
even with such variations incident to commercial
of the motor device is substantially the same as
manufacture, it is found that these components
in my prior patent; but in the improved arrange
are so nearly balanced that the armature shaft
will not be actually lifted off of its knife-edge
35 ment the front armature vane 1, as viewed in
Fig. 3, is disposed in front of the curved pole
pieces 271-281; and the other rear armature
vane 8 likewise is disposed on the same side or in
front of the other pole pieces 271-281.
Also,
40 the rear pole pieces Eil-231 are preferably slotted
there may be a downward pressure on the bear
ing at one end of the shaft or the other greater
bearing at either end.
35
This relative disposition of the armature vanes
‘l and 8 and their co-operating pole pieces 27 and
28 constitutes an important feature of this in
path of movement of the vane, as shown in Figs.
vention, because it avoids lifting of the bearing 40
spindles 6 of the armature shaft 5 off of the
knife-edge bearings, and thus obviates the pos
sibility of undesirable frictional engagement be
3 and 4.
tween the end of a spindle and the cap or re
to form strips or lips 35, which are bent forward
to provide edges constituting pole pieces in the
,
The permanent magnets 3l make the front and
rear pole pieces 281-281 at the right-hand side
of the armature shaft 5, as viewed in Fig. 3, of
one magnetic polarity say north as indicated by
N; and the other two pole pieces at 2'i1-2‘i1 at
the left of the shaft 5 are of the opposite mag
50
netic polarity S. When current flows through
the armature coil M in one direction and makes
the front armature vane ‘l a south magnetic pole,
and the rear armature vane 8 a north magnetic
pole, as indicated N and S, the front downwardly
extending armature vane 'i is moved to the right
by the repulsion and attraction with the co
operating pole pieces; .and the rear armature
Vane 8 is similarly moved to the left.
Referring more particularly to Fig. 3, it can
60
lbe seen that the forces of magnetic attraction
between each of the rarmature varies 'i and 8 and
their co-operating pole pieces 2l and 28 act in
the same direction longitudinally of the shaft
and tend to move it lengthwise in one direction
65
(to the rear as viewed in Fig. 3) against the
ball thrust bearing at the end of the shaft. 'I‘hese
armature vanes ’l and 8, however, are disposed
to extend radially from the shaft 5 in opposite
70 directions, in order that the weights of these
vanes may counter-balance each other; and the
components of the forces of magnetic attrac
55
tion which act on these vanes and which tend
to move or tilt the armature shaft 5 transversely
75 of its axis, are opposed to each other. For ex
taining member of its bearing.
Since the at
tractive forces acting onboth the armature varies
'i and 8 tend to hold the armature shaft on its
knife-edge'bearings, more positive and accurate
-alinement of the shaft is obtained, thereby as
45
suring less chance of rubbing contact between
the armature vanes and the pole pieces or other 50
parts with desired air-gaps or clearances.
During the latter part of the movement of the
armature shaft 5 from its intermediate position
in either direction, the corresponding VContact 55
finger 22 engages its normally open stationary
contact 23,' and a greater operating torque at
this point of movement is desirable to assume the
increased load of exerting the desired contact
pressure.
Such increase in torque on the arma
ture shaft 5 is obtained in accordance with this
50
invention by the projecting ledge or lip 35 which,
as shown in Figs. 3 and 4, is disposed in the path
of movement of the rear armature vane 8 so that,
as this vane approaches the position-where the
contact load is applied, there is a direct magnetic 65
attraction between the edge of this armature
vane and the pole face provided by said project
ing lip 35, said force of magnetic attraction pro
ducing an increased torque on the armature 70
shaft by acting through the lever arm represent
ed approximately by the radius of the armature
vane. It is found that such a lip 35 materially
increases the torque on the armature shaft 5 at
approximately the point in its movement where 75
2,125,257
such additional torque is desired to exert the re
quired contact pressure. Also, such building up
of torque near the extreme movement of the
armature shaft 5 improves the drop-away char
acteristics of the device, and allows relatively
large biasing forces in the counterweights I6 and
in the contact spring tension to be employed
with the desired small operating currents, and
with substantial working air gaps.
While the structural features characterizing
this invention have been illustrated in connec
tion with one specific type of motor device, as
illustrative of the nature of the invention, it
should be understood that various adaptations
and modifications may be made in the particular
construction and arrangement of parts shown
and described without departing from the inven
tion.
What I claim is:
1. A three-position motor device of the char
acter described for operating a movable element
from an intermediate biased position in either
direction comprising, a horizontally disposed
armature shaft supported on knife-edge bearings
25 at its ends, fiat armature vanes of a general sec
tor shape fixed to said shaft between said bear
ings and extending in opposite directions radially
from said shaft in parallel planes at right angles
to the axis of said shaft, a stationary field struc
30 ture having two pairs of fiat pole pieces disposed
in planes parallel with said armature vanes and
co-operating therewith through a uniform air
gap during movement of said vanes, said pole
3
plates of the ñeld structure with opposite mag- ^
netic polarities, said armature vanes being locat
ed on the same side with respect to said pole
pieces so that the turning moments of the com
ponents of the forces of magnetic attraction act
ing on said vanes longitudinally of the shaft in
directions and at locations tending to tilt said
shaft transversely of its axis are in opposition,
thereby eliminating the tendency for said shaft
to lift off of its knife-edge bearing at either end. 10
3. A three-position motor device for operating
a movable element from an intermediate biased
position in either direction comprising, an arma
ture shaft having flat vanes of a general sector
shape extending radially from the shaft in paral 15
lel planesl at right. angles to the axis of said
shaft, and a field structure having fiat pole
pieces disposed in pairs in planes parallel with
said vanes, the pole pieces of each pair being
located on opposite sides of said armature shaft 20
and co-operating with a corresponding one of
said vanes to produce a turning torque for said
shaft in one direction or the other through a
substantially uniform air-gap, each pole piece
of a pair having a portion projecting therefrom
in a direction lengthwise of said shaft into the
path of movement of the correspon-ding vane to
produce magnetic attraction with a correspond
ing edge of said vane near the extreme positions
of said shaft.
30
4. A three-position motor device for operat
ing movable elements from an intermediate
biased position in either direction to extreme
pieces of each pair being disposed on opposite
positions comprising, an armature shaft having
sides of said armature shaft, means for mag
fiat vanes of a general sector shape radially pro
netizing the pole pieces of each pair with oppo
site magnetic polarities, a stationary coil around
said armature shaft and adapted when energized
to magnetize said vanes with opposite polarities
40 to co-operate with their respective pairs of pole
pieces and produce a turning torque for said
shaft, said vanes being located on the same side
with respect to said pairs of pole pieces so that
the forces of magnetic attraction acting on said
45 vanes longitudinally of the shaft are in the same
direction, and a ball thrust bearing limiting end
wise movement of said shaft, the relative dis
position of said armature vanes and their co
operating pairs of pole pieces causing the turning
moments of said longitudinally acting forces of
magnetic attraction acting on said vanes in di
rections and at locations tending to tilt said shaft
transversely of its axis to be in opposition> and
thereby avoid lifting of said shaft off of its bear
ing at either end.
2. A three position motor device of the charac
ter described for operating a movable element
from an intermediate biased position in either
direction comprising, a horizontally disposed
armature shaft, knife-edge bearings supporting
said shaft at its ends, each bearing including a
ball engaging the end of the shaft and limiting
endwise movement thereof, flat armature vanes
of a general sector shape ñxed to said shaft be
65 tween said bearings and extending radially in
opposite directions from said shaft in parallel
planes at right angles to the axis of said shaft, a
stationary coil around said shaft for magnetizing
said armature vanes with opposite magnetic
70 polarities, a field structure including two plates
of app-roximately U-shape with their end por
tions constituting pairs of flat pole pieces dis
posed in planes parallel with said armature vanes
and co-operating therewith to produce a turning
75 torque on said shaft, means for magnetizing said
jecting therefrom in parallel planes at right
angles to the axis of said shaft, a field structure.
including two plates of approximate U-shape
with end portions forming fiat pole pieces dis
posed in planes parallel with said vanes, two of 40
said pole pieces having lips integral therewith
and projecting into the path of movement of
one of said vanes to co-operate magnetically with
the corresponding edges of that vane nea-r the
extreme positions of said shaft, adjustable stop
45
means for limiting movement of said shaft at
its extreme positions, means for magnetizing said
pole pieces, and a stationary armature coil
around said shaft for magnetizing said vanes.
50
5. A three-position motor device for operating
the movable elements of color-light signals or
the like comprising, an armature shaft, a sta
tionary coil around said shaft, flat vanes fixed to
said shaft and projecting radially therefrom in 55
parallel planes at right angles to the axis of
said shaft, a ñeld structure including pairs of
flat pole pieces disposed in planes parallel with
said va'nes, the pole pieces of each pair being
located on opposite sides of said shaft, means 60
for magnetizing said pole pieces of each pair
with opposite magnetic polarity, biasing means
tending to maintain said shaft and vanes in an
intermediate position, and adjustable stops for
limiting movement of said armature shaft and
vanes at its extreme positions, the po-le pieces of
a pair having portions projecting into the path
of movement of the corresponding vane and mag
netically co-operating‘ with the corresponding
edges thereof near the extreme positions of said
shaft, thereby increasing the torque on said
shaft at approximately the point in its move
ment where the load of operating said contact
means is applied.
OSCAR S. FIELD.
75
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