Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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This inYention relates to a molded plastic base
plate for a telephone set and in particular to such a base plate
which can accept, without alteration or the use of additional parts,
various telephone circuit parts, which parts can be of differing
forms. Thus, as an example, each telephone circuit part may be of
two forms, one which is of a form which is attached to a conventional
pressed metal base plate as by screws or rivets, and another form
which can be attached by clipping into formations on the plastic
base plate.
Conventionally, telephone set base plates are metal
pressings or stampings with the various circuit parts of items
attached thereto by screws, nuts and bolts, or rivets. In the
manufacture of telephones, many parts are made of molded plastic
and there is considerable production of scrap. This scrap has an
extremely low resale value, although the original material is
relatively expensive. The base plate of the present invention can be
molded from scrap or reclaimed material, as well as new material
although, economically, scrap material is preferable. As a base
plate is hidden, lack of a good surface finish, and odd streaks and
the like are not important. Also a fairly thick section can be used
and therefore this offsets any strength deterioration in the plastic
material.
The invention provides an economical way of using
scrap plastic material, if desired, and also enables redesigned items
having quick assembly characteristics to be used, while at the same
time permitting original items to be used with the normal assembly or
attachment arrangements.
The invention will be readily understood by the
following description of a certain embodiment, by way of example, in
conjunction with the accompanying drawings, in which:-
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Figure 1 is a perspective view of a base p1ate inaccordance with the present invention,
Figure 2 is a plan view of the base plate of
figure l;
Figures 3, 4, 5 and 6 are cross-sections on the
lines III-III, IV-IV, V-V, and ~I-VI respectively of figure l;
Figure 7 is a perspective view of a telephone
dial mechanism support bracket in position;
Figure 8 is a similar view to that of figure
7, illustrating the addition of a terminal strip to the bracket;
Figure 9 is a perspective view of the base plate
with a hook-switch structure assembled to the base plate;
Figure 10 is a perspective view of the base plate
with one form of gong and armature assembly on the base plate,
Figure 11 is a partial perspective view in the
direction of arrow A in figure 10, of the gong assembly only of
figure 10; ~ .
Figure 12 is a perspective view of the base plate
illustrating the armature assembly only of figure lOi
Figure 13 is a perspective view of the base plate
with one form of network unit attached to the base plate; ;~
Figure 14 is a perspective view of the base plate
with an alternative form of network unit attached to the base plate.
As illustrated in figures 1 and 2, a telephone base
plate, indicated generally at 10 has, in the particular example,
positions, or sites for various circuit members or assemblies as
follows: network at 11, gong or bells and ringer armature assembly
at 12 and 13, dial support brackets at 14, line switch at 15,
terminals as required at 16, and line and handset cord restraints
at 17 and 18.
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In general a base plate comprises a base web 20
with an upwardly extending peripheral rim 21. In the example
illustrated the base web 20 is in three sections 20a, 20b and 20c,
the end section 20a and 20c being raised slightly relative to the
centre section 20b, as can be seen in the longitudinal cross-sections
of figures 3 and 5. This is to match mounting levels with existing
metal base plates.
Starting at the left hand end of the base plate 10,
in figures 1 and 2, there is molded integrally with the web 21 and
the section 20a of the web 20, the line cord restraint 17. This is
of channel cross-section to receive a hooked-shaped restraint member
crimped on to the line cord in a conventional manner. Molded
integrally with the section 20 is a small group of bosses 22 having
central holes 23. Terminals can be positioned on the bosses 22, the
terminals having tangs which piercethrough thinned portions formed by
recesses 24, the tangs being bent over under the base plate. The
holes 23 serve as clearance holes for the screws of the terminals.
Other terminals can be similarly attached at the other end of the
base plate at 16.
Extending across the base plate is next the area 12
for the gong assembly and then adjacent to this position the
gong armature assembly position 13. The armature and gong assemblies
can be of two forms. A conventional form comprises a casting -
usually a zinc casting - which has an upright web which carries the
two gongs or bells, and a base web which carries the coil, armature
and striking arm etc. Such an assembly can be mounted on the new
base plate by positioning the base web within the area 13, the
bottom edge of the upright web resting across the base plate in area
12. The assembly is then attached by self-tapping screws entering
bosses 26.
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An alternative arrangement has been proposed in
which the gong assembly is separate from the armature assembly.
This avoids using a fairly complex metal casting which is replaced
by simple and cheap metal stampings, one for the gong assembly and
one for the armature assembl~. The gong assembly is held in place
by the ends of the metal bracket being inserted under projections,
sliding over a snap member. Thus, in figures 1 and 2 there are two
upwardly extending projections 27 and 28. Projection 27 extends
parallel to the longitudinal axis of the base plate, near one edge,
having a flange extending toward the centre of the base plate. This
can be seen in figure 6, the flange indicated at 29. To permit
entry of the core in molding, a hole 30 extends through the base
plate. Projection 28 is inclined slightly to the longitudinal axis,
as illustrated. The projection has a top flange 31 extending towards
the longitudinal axis and is positioned near the opposite edge relative
to the projection 27. At a position intermediate the projections
27 and 28, and nearer to projection 27 than projection 28, is a snap .
member 32. Snap member 32 is defined by a U shaped slot or hole 33
through the base plate, and an inclined rib 34 is formed on the
upper surface at the free edge 35. This can be seen in figure 5.
The snap member is positioned to one side of the space or area between
the two projections and the free edge 35 of the snap extends towards
this space - area 12. To assemble the gong support bracket to the
base plate, a small projection at one end is inserted under top
flange 31 of projection 28, with the bracket inclined and resting on
top of the snap member 32. The bracket is then pressed down and
; rotated to slide a small projection at the other end under the flange
29 of projection 27. As the bracket is pushed completely home it
clears the free edge 35 of the snap~member 32, which has been depressed
while the bracket is installed, and the snap member snaps up with the
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rib 34 against the edge of the bracket, holding it in position.
The gong assembly on its bracket can be removed by first depressing
the snap member 32 and then swinging out the bracket fro~ engagement
with the projection 27.
The new, separate, armature assembly is held in
position by engagement under a number of projections 40 to 45, each
having a top flange. The metal stamping on which the armature
assembly is mounted is shaped so that it has portions which fit
under the flange of the projections. Thus one corner fits under
projection 40 and another corner fits under 41. A sideways extending
tab extends under projection 42 and one side extends under 43.
Finally two tabs extend under projections 44 and 45. The stamping
is shaped so that it can be dropped onto the position 13 and then
slid upwardly in figure 1, with the various parts sliding under the
flanges of the projections. Slight downward pressure is maintained
on the assembly while sliding to depress a snap member 46, similar
in form to snap member 32. As the bracket and assembly slides into
final position its edge clears the free edge 47 of the snap member
46, rib 48 engaging with the edge of the bracket to retain it in
20 - position. Removal is by depressing the snap member to release the
bracket.
Thus there is provided an arrangement in which both
existing forms of gong and armature assembly and new form of separate
gong assembly and armature assembly can be attached to the base plate
without alteration or provision of adaptors or the like.
Considering now the network which is positioned at
area 11, an older form merely sits in the area 11 which is defined by
a series of short, upwardly projecting, ribs 50 and by the step 51
between section 20a and section 20b of the base plate. The network
3Q is then attached by rivets through projections on the network base
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and through h~les 52 in the base plate. The new form of network
rests on the ribs 50. At two corners of the area 11, on one edge,
at 53 and 54 are upward projections with top flanges and small
locating ribs are provided at 53. At the opposite edge of the area
11 to the projections 53 and 54, and at approximately the centre, is
a snap member 56. This snap member is somewhat similar to snap
members 32 and 46 in that it is defined by a U-shaped slot 57, but,
as seen in figure 4 it has an upstanding flange 58 at the top of
which is an inwardly extending rib 59 having an inclined upper
surface 60. The new net~ork is slid into position with corners of
its base under the projections 53 and 54. Slight downward pressure
on the network then depresses the snap member 56, the flange 58
flexing outward under the action of the network base on the inclined
surface 60. Once the network is fully down the snap member returns
to its original position and the rib 5~ extends over the base of the
network. To permit removal the flange 58 is recessed and the rib 59
divided at the centre, at the position indicated at 61 in figures 1
and 2, to permit insertion of a tool such as a small spike which can be
used to lever the flange 38 outwards and thus release the network.
; 20 The line switch, positioned at area 15, has flanges
one of which engages at one corner under a projection 65 which
extends from projection 54 for the network, and having a top flange.
Projection 43 for the armature assembly at area 13 also has a flange 66
extending into the line switch area and a further projection 67 provides
a further fastening member. The line switch is slid with its flange
under the top flanges of projections 65 and 67, and under flange 66.
Pressure on the line switch depresses a snap member 68 similar to
snap members 32 and 46, and a rib 69 on the free edge engages with the
edge of the line switch base. The line switch can be of existing form
3Q and the projections and other features of the base plate positioned
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to engage ~ith the bottom of the line switch. The line switch can
be removed by depressing the snap member 68.
The remaining main feature or item is the dial
support bracket, which is positioned at area 14. This bracket
extends for a major part of the width of the base plate. The bracket
is generally of U-shape having a flat base web and two upstanding
legs - the bracket conveniently formed 6y bending a flat strip of
metal. At the upper ends of the legs are provided slots and/or holes
for attachment of the dial structure. The bracket is installed, or
attached by a slightly rotative sliding movement. Two diagonally ~ ;
opposed projections 75 and 76 extend from the base plate, the
projections having top flanges 77 and 78. Opposite each projection
is a snap member 79 and 80, snap member 79 opposite projection 75 and
snap member 8a opposite projection 76. The bracket is first
positioned by resting the base web on the base plate on the section
20c, at an inclination and resting on the snap members 79 and 80.
With slight downward pressure and rotation - anticlockwise in figure 1,
the bracket base engages under the flanges 77 and 78 and eventually
moves off of the snap members, which have been slightly depressed.
The members then snap up and engage the sides of the bracket base and
retain it in position. Removal is by depressing the snap members
and rotating the bracket out of engagement with the flanges 77 and 78.
Figure 7 illustrates a dial support bracket 80 in
position. The base web 81 rests on the section 20c of the base plate ` ?
and the legs 82 extend upwards. Slots 83 and holes 84 provide for
attachment of the dial mechanism. If desired an additional terminal
strip85 can be provided by being inserted between the legs 82,
projections on the ends of the terminal strip fitting in slots 86 in
the legs 82.
3Q- Figure 9 illustrates the line switch 90 in position ~;
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on the base plate. The main frame member 91 has an outwardly
extending flange 92 at each side and these flanges extend under the
flange 66 and the top flange at proiection 67 at one side and under
the top flange of projection 65 at the other side. The snap member
6~ bears against one edge of a flange 92.
Figure 10 illustrates the attachment of a present
form of gong and armature assembly 95 to the base plate. The metal
casting frame is seen at 96, the gongs at 97, the armature assembly at
98 and the striker at 99. A lug or extension 100 at each end of the
frame 95 rests over the related boss 26 and screws 101 are screwed
into the bosses.
Figures 11 and 12 illustrate the alternative form of
separate gong assembly la5 and armature assembly 106. In figure 11,
can be seen the metal bracket 107 having a main flat portion 108 and
a bottom flange 109. The gongs 97 are mounted on the bracket portion
108 which extends normal to the flange 109. A slot 110 provides
access through portion 108 for the striker and small vertical slots
111 provide alternate locating positions for the striker loading spring,
the loading spring being positioned in one or other of slots 111 to
predetermine the spring load on the striker and thus serve as an
initial setting. The normal loudness control is provided being
positioned to affect the left gong in figure 11. The control knob
for the loudness control is accessed through an aperture 112 in the
base plate (figures 1 and 2). The ends of the flange 109 extend
under the top flanges of the projections 27 and 28 and is held in
position by the snap member 32. Also, as illustrated in figure 11 a
small tongue 113 is cut and bent out of the main portion 108 at its
junction with the flange 109 the tongue extending in a recess formed
by extension of the projec~ions 40 and 53. This assists in stabi1izing
the bracket 107.
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Figure 12 il1ustrates the armature assembly 106. The
assembly includes a bent framework member 115 having small webs 116
positioned to engage under the top flanges of the projections 44 and
45. Another small web engages under the top flange of projection 43.
Also small flanges on the side of the assembly not seen in figure 12
engage under the top flanges of proiections 40 and 41. Snap member
46 bears against the frame member 115. The striker is seen at 117
and striker loading spring at 118.
Figures 13 and 14 illustrate the attachment of t~o
alternate forms of network, figure 13 being for the previous and
older form and figure 14 for the newer form. In figure 13 the network
120 is of general box-like form which rests on the surface of the
base plate in the section 20b, located hy the ribs 5Q. Two small
lugs or projections 121 extend from the base member of the network
and these align with holes 52 with rivets 122 attaching the network
to the base plate.
In figure 14 the newer type of network 125 is shown.
This is built up on a printed circuit board 126. Two corners of the
board 126 fit under the top flanges of projections 53 and 54. The
board resting on the ribs 50. As the network 125 is pressed down it
deflects the snap member 56 (figures 1 and 2) with the printed circuit
board eventually engaged under the rib 59 (figure 4).
The line and handset cord restraint pillars 17 and 18
are molded adjacent thinned pushout portions 127 and 128 in the
peripheral rim 21. When modular plugs and sockets are used, that is
when the handset cord, and also the line cord, is plugged into the
telephone set, the plugs can be attached by sliding onto the peripheral
rim 21 before assembly of the top housing to the base plate, at
positions adjacent to the pillars 17 and 18.
Provision for attachment of other items can be made.
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Thus a line switch, and indicator, can be mounted on section 20c by
means of scre~s passing through holes 130 (figure 1). The base plate
is attached to the telephone top housing by screws passing through
the holes 131.
Additional holes 132 are provided for the attachment
of rubber feet. Depending upon needs, or requirements three or four
feet can be provided. Thus, considering figure 2~ two feet can be
attached at the holes 132 at the right hand end, while a single foot
can be provided at the central hole 132 at the left hand end, or two
feet can be provided at the top and bottom holes 132 at the left hand
end. The holes 132 have bosses 133 surrounding them an the under-
surface of the base plate for reception of the rubber feet. The
rubber feet normally extend only a very short distance below the
bosses and if a single foot is provided at the left hand end in figure
2, the other two bosses limit any tilting. It can be more useful to
be able to provide three feet, for a three point support, as some
distortion of the base plate can occur during and after molding, creating
prohlems in obtaining a non-rocking support if four feet are used.
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