An Improved Switch Board Indicator or Annunciator.
Year: 1897

page_text: COMPLETE SPECIFICATION.
An Improved Switch Board Indicator or Annunciator.
I, NEWMAN HENRY HOLLAND, of 2728 St. Catherine Street, Montreal, Canada,"
Electrician, 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 relates to an improved indicator or annunciator designed more
particularly for use on telephone switch boards and formed substantially in two
separate and independent portions, the magnet thereof forming one of these
portions, and the other or operative portion comprising the shutter and armature
and a carrying plate on which these latter are mounted.
One important feature of the said invention is that the magnet of the indicator
or annunciator is detachably secured to the said operative portion thereof and to
the switch board from the rear thereof in a manner permitting of its easy removal,
in case of repairs being necessary, without disturbing either the switch board or
the other portion of the indicator.
A further feature of the invention is that the said operative portion of the
indicator or annunciator is situated entirely on the front of the switch board, and
the carrying plate thereof is held in position partly by a set screw, and partly by
the engagement therewith of lugs or projections formed on the pole piece of the
magnet.
In order that the said invention may be readily understood I will proceed to
describe the same by aid of the accompanying drawings, in which
-
Figure 1 is a side view of my improved indicator or annunciator with the
shutter in its raised or closed position.
Figure 2 is a front view thereof with. the shutter in its fallen or open position.
Figure 3 is a longitudinal section to a larger scale, of part of the indicator
shown in Figure 1.
Figure 4 is a rear view of a portion of the switch board showing the engage-
ment of the aforesaid lugs with the carrying plate, the body of the magnet being
removed.
Figure 5 is an end view of the said magnet.
a is the switch board, which may be formed of metal or other suitable material,
and is provided, where an indicator or annunciator is to be attached, with an
aperture a. b is the magnet of the indicator or annunciator which magnet is
provided with terminals 61 and with a metal or other sheath or casing 62 in the

page_text: usual manner. The end of the magnet opposite the terminals is adapted to enter
the aperture a¹ in the switch board. The pole, of the magnet is provided with a
reduced portion or neck 3 carrying the lugs or projections b
cis the carrying plate for the operative portion, of the indicator or annunciator,
which plate is provided with an oblong aperture c opposite the aperture a¹ in the
switch board. The length of this aperture is such as to admit of the passage through
it, of the aforesaid lugs whilst the width of it is just sufficient to accommodate the
reduced portion or neck 63. Thus when the lugs are passed through the aperture c
and the magnet is turned through a quarter of a revolution on its axis, the said
lugs project over the edges of the aperture and serve to securely connect the magnet
to the carrying plate. The lugs may be tapered or have their inner faces inclined,
se that in turning they tend to press or draw the magnet and carrying plate
together.
In order to fix the magnet in this position and at the same time to permit of its
ready detachment from the switch board and carrying plate, an annular groove 65
is formed around the end of the sheath 62 and a screw 65 is arranged in proximity
thereto on the switch board, the head of which screw projects into the said groove
but is cut away on one side as at 66 sufficiently to enable it to clear the groove.
The arrangement is such that only a partial turn of the screw is required to cause
its head to grip or engage with the groove, so fixing the magnet in position, while
conversely by turning the screw partially in the opposite direction the cut away
portion is brought opposite the groove thus allowing the magnet to be turnel
on its axis to disengage the lugs b, and also permitting of its removal from the
switch board after such disengagement. 2 is the set screw by which the carrying
plate c is primarily held in place on the switch board, the action of this screw being
supplemented by that of the lugs & by the magnet.
d is the shutter of the indicator or annunciator. This shutter is mounted on a
hinge-pin d supported at its extremities by a pair of lugs ³ formed on the
carrying plate, and is provided with a tail piece d2 and with a pair of offsets 'or
projections d. The tail piece serves when the shutter falls to complete a night
bell circuit in the usual way through a contact, while the projections serve for
locking the shutter in its raised or closed position as hereinafter described.
a
e is 'the armature of the magnet. This armature is arranged parallel with the
shutter, when the latter is raised or closed, between it and the magnet and consists
of a suitably shaped plate, on the front or outer side of which is provided the
number or other indication identifying the circuit to which the indicator corre-
sponds, as shown in Figure 2. This armature is mounted near its upper part on
hinge-pin e carried by a pair of lugs on the plate c. Above the pin e' the said
armature has a pair of outwardly surved fingers e² against which the upper edge
of the shutter rests when raised or closed. The lower edge of the armature
normally lies above and engages with the aforesaid projections 3, thereby pre-
venting the armature from falling. This engagement takes place by the shutter,
in being raised, striking the fingers and thus turning the armature slightly on
the pine so that its lower edge moves outward above the said projections into the
engaging position indicated in Figure 3.
It will be seen that should the magnet be energized when the parts are in this
position, the armature e will be attracted and by turning inwardly on the said pin ei
will remove its lower part from engagement with the projections while the
curved fingers will simultaneously move outward and push the shutter openin
a positive manner, thus preventing any chance of its accidentally sticking in its
upright or closed position.
L'
Instead of the lower edge of the armature resting directly on the projections d³
in the manner described the said armature may extend downward sufficiently to
enable it to be operated by the finger. Under these circumstances the said
armature is provided with a ledge, shoulder or projection adapted to engage with
the said projections when the shutter is raised.
4
In some cases instead of the switch board having an aperture a¹ to receive the

page_text: end of the magnet it may beprovided on its rear side with a circular recess
ccrresponding in size to the said aperture and having a central opening, to receive
the end of the core of the magnet, such core in this case projecting slightly from
the end of the magnet and having as before a neck formed with lugs to engage the
carrying plate. Furthermore instead of the screw 5x with the cut away portion b
I may employ any other equivalent device adapted to engage with the groove in
the magnet casing and hold the said magnet rigidly in place.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:
1. A switch board indicator or annunciator provided with means substantially
as described whereby its magnet can be readily removed without disturbing either
the switch board or the operative portion of the indicator or annunciator.
2. A switch board indicator or annunciator the magnet of which is independent
of the operative portion and is situated at the rear of the switch board, and the
said operative portion being situated on the front thereof substantially as described
and for the purpose specified.
3. A switch board indicator or annunciator having its shutter and armature
mounted upon a common carrying plate, the armature being adapted to engage
with projections on the shutter in order to keep the latter raised or closed, and
having fingers projecting towards the shutter and serving to throw the latter
forward into its open position when the armature is actuated, substantially as
described.
4. A switch board indicator or annunciator having its shutter and the armature
of its magnet pivotally mounted upon a common carrying plate to which the
magnet is adapted to be connected by lugs or projections thereon, substantially as
described.
5. A switch board indicator or annunciator having its magnet formed with an
annular groove with which a screw head engages, substantially as described and
for the purpose specified.
6. My improved switch-board indicator or annunciator constructed substantially
as hereinbefore described with reference to the accompanying drawings.
1007
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.