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Патент USA US2408902

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Oct. 8, 1946'.
A. ARNOT
2,408,901
ELECTRIC SWITCH vSENSI'I'IVE TO S-MALL OPERATING MOVEMENTS
Filed April 30. 1943' 1
“:EIEit
.a.
i
2,408,901
Patented Gct. 8, 1946
UNITED STATES PATENT OFFICE
2,408,901
ELECTREC SWITCH SENSITIVETO- SMALL
OPERATING MOVEMENTS
Alf-red Arnot', Warrington, England, assignor to
Aeronautical & Mechanical Investments» Lim
ited; a British company
Application April 30, 1943, Serial No. 485,220
In Great Britain April 23, 1942
2 Glaims. (Q1. 200-153)
1
This invention comprises improvements in or
relating to electric switches sensitive to small op
erating movements.
It is an object of this invention to provide an
electrical switch mechanism‘ which is sensitive
to very’ small movements of the operating mem
ber. For example in the mechanism described in
patent application No; 469,270, which comprises
an electrical device for transmitting movement
from a transmitter to a receiver such a switch 1O
mechanism is called for, and maybe necessary
both at the transmitter and‘ at the receiver.
According to the present invention an- electric
switch mechanism comprises in combination‘ a
base, a contact-carrier pivotally mounted on the
base and having a pallet-face in a plane to one
side of the pivotal axis and facing away‘ there
from, a switch contact-member operatively con
nected to the contact-carrier so as to be oper
2.
The switch mechanism comprises an operating
spindle II‘ which is rotatably mounted and car
ries at one end a head l2 containing a transverse
spring plunger [8 which constitutes a switch-ac
tuating member, projects from one side of the
head and has a knife edge ill, the» line of which
extends in a direction parallel with the aXis of
the operating spindle ll. Concentric with the
spindle H and surrounding it, but mounted-for
independent rotation, is a circular switch base l5
of metal and on the switch base there is pivoted
on a post l6, close to the» spring plunger l3‘, a
contact-carrier H in‘ the form of-v an oblong block
of metal having a pallet face 18 which engagesthe
knife edge 14 on the spring plunger I3‘; The
pallet-iace 18 in its neutral position is at right
anglesto the line-of'pressureof the-spring plunger
l3, the axis of- the pivot-post IQ of the contact
carrier being in this positionv intersected; by- the
line of pressure‘ of- the-spring plunger it‘ through
ated when the contact-carrier rotates about its 20 the knife edge M». The contact-carrier has a
aXis, and an actuating-member having a pallet
V groove 19» cut in- one end and on the» rotatable
engaging portion which is mounted so as to be
switch base there is an upstanding» block 28 hav
yieldingly pressed on the pallet face and to be
ing another V groove 2 li which faces the V groove:
so movable that the line of pressure can be shifted
H! in the contact-carrier. Between the two V
to one side of the contact-carrier pivot to actuate
grooves there extends a piece of ?at-section:
the contact-member inv one direction, and to be
spring-steel 22» which is of curved or sinuous for-‘
returned to return the contact-member‘
mation so that it constitutes a» somewhat stiff
The actuating-member may be capable of being
compression spring‘, and thelocation of the parts
centered so that its-line of pressure passes through
the pivot axis and of being moved to either side 30 is such‘ that when‘ the contact-carrier Hi is in
its mid position with the line of pressure of. the
to move the contact-member correspondingly,
spring plunger 13 intersecting the axis. N3 of the
and the contact-member may engage two con
pivot
the spring 22 which extends between the V
tacts, one when moved to one side and the other
grooves has a line of pressure which also inter
when moved to the other. Thus it is possible to
sects the axis it of the pivot. The spring 22 is
make the switch member operate as a two-way
thus a toggle spring, and while it does not prevent
switch with a neutral or off position in the centre,
the spring plunger l3 from holding the contact
if desired, although it is within the scope of the
carrier ll at rest in its central or normal posi
invention to use the switch member for closing
tion,
it assists in pushing the contact-carrier over
a single contact only.
Preferably the contact-carrier is further con 40 to one or other of its extreme positions immedi
ately the spring plunger of the operating member
trolled by a spring mounted on the base in such a
is moved so that it presses either to one side or to
position as to act as a toggle-spring and thus to
the other of the aXis of the contact-carrier IT.
increase the certainty of movement of the con
From the other end of the contact-carrier I‘!
tact-member into contact-engaging position.
there
extends a spring arm‘23 which constitutes
The following is a description, by way of ex
a contact-member and terminates in a double
ample, of one construction of switch mechanism
sided contact 24. The contact 24 plays between
in accordance with the invention:
two ?xed insulated contact posts 25, 26 on the
In the accompanying drawing,
switch base. A bridge-piece 21 carries a bearing
Figure 1 is a front elevation of an electric
for the end of spindle ll.
switch mechanism according to this invention;
Therefore if the parts are in their normal po
Figure 2 is a plan;
sition the axis of the spring plunger l3 of the
Figure 3 is a diagrammatic perspective view of
operating spindle will intersect the pivot l6 of
the switch mechanism and of one possible ar
the contact-carrier H and the switch contact 24
rangement of parts and connections for auto
55 will be held centrally between the two ?xed con
matic servo-operation.
2,408,901
4
tacts 25, 26, without touching either of them.
this will be attained. Stability may be further
A very small angular de?ection of the operating
spindle I I in either direction will cause the line
of pressure to be altered and the switch contact
increased, at the expense of sensitivity, by slightly
?attening the knife edge.
It will be appreciated that while a rotatable
actuating member and rotatable switch base have
been described the invention is applicable to other
will be brought ?rmly into engagement with one
or the other of the contacts 25, 26 on the rotat
able sWitch base.
If such a swtich mechanism
cases, for example where the switch base is ?xed,
is employed in apparatus of the kind described
in the aforesaid patent application No. 469,270
the operating spindle ll of the switch may con
or where one part (such as the actuating mem
ber) moves in a straight line relatively to the
other part (such as the base) instead of being
stitute the control shaft on the receiver, as shown
in Figure 3, and the switch base I5 may be con
nected to a follower shaft 28, by means of the
bridge piece 21 or otherwise. This mechanism
thus takes the place of the cam-closed switch
contacts described in the aforesaid specification.
In Figure 3 the parts are similar to Figures 1
and 2 but the base 15 is shown as having gear
teeth around its edge meshing with a pinion 29
on a shaft 30 of a reversible motor 3|.
rotatably mounted.
I claim:
1. An electric switch mechanism comprising a
base, a pivoted contact-carrier mounted on the
base and having a pallet-face in a plane to one
side of the pivotal axis and facing away there
from, a switch contact-member carried by the
contact-carrier so as to be operated when the
contact-carrier rotates about its axis, an actu
The shaft ‘
H_ is operated in either direction ‘by magnetic
pawl-operating devices the pawls of which oper
press said pallet-engaging portion against the
pallet-face of said contact-carrier, said actuating
ate a ratchet wheel 32. The motor is connected
by line 33 to a source of electric power 34 and by
lines 35, 36 to the contact posts 25, 2B.
The con-
tact 24 is connected by line 3'! to the other ter
minal of supply. Thus when contact 24 is closed
against 25 the motor 3! will operate in one di
rection and when closed against contact 26 the
motor will operate in the other direction.
The
directions of movement are arranged to be such
that the base l5 always tries to follow the shaft
H and thus shaft 28 is motor-driven to the same
extent of movement as shaft I l. The motor may
be such as the one described in British patent
application No. 6373/ 41.
The switch may also be used in a transmitter
ating member having a portion movable towards
the pivot of the contact-carrier and means to
~
member being mounted so that its line of pres
sure passes through the axes of said pivot and
is capable of movement to either side to move
the contact-carried correspondingly, a pair of
contacts adapted to be alternatively engaged by
said contact-member depending on its direction
of movement so that the contact member may
act as a two-Way switch member with a central
neutral position, and a spring mounted on the
base and engaging the contact-carrier in such a
position as to act as a toggle-spring and thus to
increase the certainty of movement of the con
tact-member.
2. An electric switch mechanism comprising in
combination a rotatably mounted base, a contact
carrier pivoted on said base eccentrically to the
tion N 0. 469,270, where the transmitter has a con 40 center of rotation thereof and having a pallet
trol‘ shaft carrying spring contact arms.
iace facing towards the center of rotation of the
In the mechanism herein described it is nec
base, a switch contact-arm extending from said
essary that the spring loading behind the knife
contact-carrier, a contact on the base engageable
edged plunger I3 on the operating spindle II
by said contact-arm, a rotatable actuating mem
should be great enough to ensure that the mech
ber coaxial with the base, a pallet-engaging por
anism will re-set to neutral position, that is to
tion on the actuating member movable radially
say with the switch contact 24 out of engagement
outward into contact with said pallet-face, resil
with either of the contacts 25, 26 on the switch
ient means for urging the pa1let~engaging mem
base, after it; has been displaced, when the op
ber toward said pallet-face, and a toggle compres
erating spindle regains the position in which the ' sion spring mounted on said base and engaging
plunger is in line with the axis of the contact
said contact-carrier.
mechanism of the kind described in the alterna
tive form of apparatus in the aforesaid speci?ca
carrier. If the spring loading is su?iciently great
ALFRED ARNOT.
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