Note: Descriptions are shown in the official language in which they were submitted.
Case 2920
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COMPOSITE TERMI~AL SYSTEM
This invention is directed to an improved
solderless connector, and in particular to an improved
connector suitable for use with electrical devices, in
particular ballasts, and to the improved ballast thus
produced.
Solderless wire connectors are well known,
as can be seen in Canadian Patent Nos. 891,711, issued
` January 25, 1972 to Enright et al, 892,782, issued
~` ~ 10 February 8, 1972 to Driscol and 939,033, issued
December 25, 1973 to Serin.
The present invention provides an improved
solderless connector, together with a connector
mounting block suited ~or use with electrical devices,
in particular ballastsj and to a method for using the
improved connector.
One existing method for producing lighting
ballasts has included the provision of metallic studs
mounted on insulators, to which the ballast
connections were secured by soldering~ In accordance
with~the present invention, the improved solderless
connection is provided with a resilient flat plate
having at least one pair of extending elements
defining an open ended~wire receiving slot, one of the
elements comprising a cantilever spring to provide in
use a predetarmined lateral face acting against a
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wire conductor when pushed laterally into the slot~
The finish of the edges of the brass sheet stock
obtained when the contact elemen-t is stamped out is
sufficiently sharp to penetrate through insulatiny
material covering the surface of a wire conductor, to
ensure ob-~aining a reliable electrical contact when
the wire is pushed laterally into the slot. The shape
of the cantilever spring member, in addition to
facilitating the penetration of insulating material,
also deforms elastically upon insertion of a wire to
the bottom of the slot so as to trap the wire within
the slot, to substantially preclude accidental
withdrawal of the wire from the slot. The geometry of
the element allows use of wires selected from a range
of sizes.
The provision of contact elements having
two, three or more slots in each element permits the
insertion of single wires into a slot, with the body
- of the contact providing electrical interconnection
; 20 between adjacent individual wires.
; rrhe present invention further provides an
electrically insulating mounting block to receive a
plurality of solderless contact elements in inserted
relation thereinu The contact elements are
self-anchoring, each having a plurality of projecting
hook portions to engage the mounting block in
attaching relation thereto.
rrhe mounting block herein disclosed includes
a plurality of winding posts to receive wire
conductors in wound relation thereabout, thus
permittiny selected wires each to be initially
positioned in preliminary entered relation with a
selected contact element slot.
he mounting block is further provided with
locating means to facilitate assembly of the blocks in
secured relation with an electrlcal device such as a
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ballast. The locating means includes an external
shoulder portion and spacer nibs for precise
positioning of the mountiny block on the device, and
at least one protruding leg for attaching the block to
the device, as by clinching a struck out tab from the
; device in holding relation with the protruding leg.
The mounting block leg portions, in the
preferred embodiment include extended foot portions
that serve collectively to support the device. Thus,
in the case of a ballast, the extended foot portions
collectively maintain the ballast windings in
suspended relation positioned clear of adjacent casing
or other components until final potting or
; encapsulation is completed.
The respective structural characteristics of
the subject invention lend themselves to low cost mass
production, with the electrical contact elements being
stamped rom selected conducting material, the
mountiny block having slots therein precisely sized to
~0 receive the contact elements within individual
isolated slots being injection molded, preferably from
a suitable polycarbonate resin. The elements further
lend themselves to facilitated assembly, with minimal
hand operations such as positioning the connector
elements in entered relation in their slots and tying
the individual conductors to selected ones of the
winding posts so as to position each wire in aligned
relation with a desired one of the connector slots.
In selecting the contact element material
from sheet stock such as phosphor bronze, berylium
copper or brass, phosphor bronze possesses the
required strength and elasticity at a more acceptable
cost than berylium copper, which is a superior
conductor. The lower elasticity of brass
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limits the extent of allowable elastic deformation,
requiring More precise sizing of the conductor wires
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that may be used therewith. Elastic deformation of a
cantilever portion of the contact element, upon
insertion of a conductor within the slot thereof, has
amounted to a 15 deflection, while the generation of
flattened side surfaces in the conductor has led to a
change in cross section area o~ about 15~ This local
change in wire area serves to anchor the wire against
pull-out forces.
The forcing home of connectors into their
slots in the mounting block, and ~orcing the
positioned wires transversely into the respective
connector slots can then be automated, to eliminate
hand labour to a significant extent, with consequent
labour cost reduction.
Certain embodiments of the invention are
described, reference being made to the accompanying
drawings wherein:
Figure 1 is a magnified view, in front
elevation of the subject solderless connector contact
- 20 member and a portion of a terminal block;
Figure 2 is a front elevational view of a
terminal block in accordance with the invention;
~ Figure 3 is a front elevational view of a
;~ terminal block in assembled relation with a ballast;
-~ 25 E'igure 4 is a plan view of the ballast, and
Figure 5 is a section at 5-5 of Figure 2~
Referring to Figure 1, a contact member 10
for a solderless connector is stamped from cold drawn
brass or phosphor bronze stock, having a central
30 pillar 12 and at least two side pillars 14, 160 Each
of the side pillars 14, 16 has a cantilevered blade
~ portion 18 attached at the top to a leg portion 20.
- The flanks 22 of the blade portions 18, together with
the flanks 24 o~ the pillar 12 are curved to ~orm a
convergent slit within which a wire W (shown in
phantom) may be ~orced causing the blade portions 18
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to deflect. The shape of blade portions 18 is such
that as the wire l~ ls forced inwardly towards the root
of the slit 17 causing progressive bencling o-f the
blade portion 18, the upper end of blade portion 1~,
being stiffer, tends to return towards its original
position -thereby trapping the wire W within the slit
17.
The contact member 10 has a pair of opposed
hook end portions 28 which embed themselves in the
adjacent slot wall of terminal block 30, within which
slots the contact members 10 are inserted.
Turning to Figure 3, a ballast 40,
comprising a stack of laminations 41 having a coil 45
set therein is provided at each end thereof with a
terminal block 30. Each terminal block 30 has a pair
of indented post members 44 by which the block 30 is
secured to the ballast by way oE crirnp 48 into the
post indentation. The crimps 48 are struck from an
end frame portion of the ballast 40 and clenched in
gripping relation over the post members 44. The block
30 is firmly seated on the top of the core structure
of the ballast 40, whereby the remote ends of post
members 44 extending beneath the level of the other
positions of the ballast 40 serve as
supporting feet therefor, prior to encapsulation of
the ballast. The outer wing portions 29 of the
terminal blocks 30 extend above the level of the other
components of the ballast 40 so as to afford a
protective envelope to the respective components,
permitting inversion of the ballast in supported
relation by wing portions 29, if desired.
Referring to Figures 1, 2 and 5, the
ter~inal block 30 has a crenelated intermediate body
portion 32, the individual crenelations 34 each having
a slot 37 therethrough within which a respective
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contact memb~r 10 is inserted.
The opposed hook portions 2~3 of the members
10 engage in hooking relation with the ends of the
respective slots 37, to preclude withdrawal of each
contact me~ber 10 from its respective slot 37.
The spaces between adjoining crenelations 34
provide access for transverse insertion of individual
wires downwardly into the convergent slit provided by
blade portions 18 and pillar 12 of the contact member
10 10 .
As sho~n in Figures 2, 4 and 5, a number of
L-shaped tie-off posts 36 extend from the front of the
terminal block 30, each tie-off post 36 having a
horizontally extending leg portion 37' and an
upstanding foot portion 38.
In use, enamelled wires W (39) are laid into
the respective slits 17 and held in position by
winding the free end of the wire about an adjacent
tie-off post 36.
With all of the wires thus positioned in the
`~ entrance to their respective slits 17, although not
forced downwardly into contact-making relation within
the slits 17, and being held in such entered relation
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by having the free end of each wire wrapped about an
appropriately positioned tie-off post 36 so as to
maintain the respective wires in positioned relation,
the ballast 40 may then be positioned in a mechanical
pressing device, for applying transverse force
downwardly against the wires 39, so as to cause
stripping of the varnish insulation simultaneously as
the wires are displaced into the bottom of their
respective slits 17. It wiIl be understood that this
mechanization step is optional, and manual positioning
~ of wires 39 into slits 17 may be used.
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