Note: Descriptions are shown in the official language in which they were submitted.
~098421
Cables s~ch as are widely used in tha actuation
o~ automotive parkin~ brakes and clutches, and have
other applications in industrial, marine and aircra~t
contexts, com~only hæve a central core that can
reciprocate axially within a conGuit. T~e conduit
may be iormed from spirally wound wire, or spirally
wound wire may form the outer oi ~everal concentric
layers. If such a conduit is cut ~rom a continuous
len3th, then there ~s the risk that the wire wlll
become unwound in the region oi the cut. This, in
itsel~, c&n be unsatisfactory but if it is then
necessar~ to provide that conduit with a termination
member, ~here is the additional problem of capturing
the "frayed" wire or wires within the termination
member. The present invention arose ~rom a consideration
oi this problem.
According to the present invention, thera is
provided a method o~ ~ormin~ z unit comprisin~ a conduit
iormed $rom spirally wound wire, or ~rom two or more
2~ layer~ oi which the outer is ~ormed ~rom spirally wound
wire, and atermination member ~ixed around an end portion
oi the conduit and holdine the parts o~ the splrally
wound wire that lie between the ends o~ the termlnation
lOq84Zl
member in position relatively to each other, in
which method the end portion, and an extension of the
conduit to which the and portion is inte~rally
connected is held within a mould, thermoplastic
material is injected into the mould to form the
termination member, and, after the thermoplstic
materiæl has set,a cut is made to separate the condult
~rom the integral extension.
Thus, the parts oi the wire are held in position
by the termination mer.~ber without the provision of
additional maans ~or the purposa.
The mouldin~ operation may form only a sin1e
termination me~ber, but it may be arran~ed that two
are ~ormed simultaneously by the single moulding operation,
and the two are then separated by the cut that separatas
the conduit ~rom its extension, the extension being
included with the second termination member in another
unit.
10~84Zl
The spirally wound wire may provide
widely spaced convolutions overlying another
layer of more closely spaced convolutions,
and the termination may serve to hold turns
o~ both layers in position relat~e~y
to each other. By the moulding process,
the thermoplastic material may be forced
closely into the spaces between adjacent
convolutions, and so provide a seal between
10. them.
The termination member may have a
length and flexibi~ity that serve to dis-
tribute vibration and bending stresses; in
particular, it may be so de8igned that when
it is intended to mate within another ~itting,
the stresses are not concentrated at the
entry point to the iittln~.
. . ~
iO9842~
By way of example, an embodiment of the present
invention will now be described with reference to
the accompanying drawin~s in which:
Figures lA and lB are side and end views of a
unit comprising a conduit and a termination member
fixed around ~ end portion of the conduit;
Figure 2 is a schematic view in axial section
of moulding apparatus by which the ~he termination
member may be ~ormed; and
Fi~ure 3 is a view in side elevation o~ the product
that is yielded by the mouldin~ apparatus illustrated
in Figure 2
The unit illustrated in ~igures lA and lB includes
a helical wire ~lexibl~ conduit, of which a part is
indicated at 1~, and a cylindrical plastic termination
member 11 moulded on to the end portion of the conduit lO.
The conduit 10 comprises an inner,helically wound, core 12
of flat wire, an intermediate layer 13 of helically
wound conti~uous wires coiled with a relatively long
pitch, and an outer layer 14 of helically wound turn~
which act to retain the wires o~ the itermediate layer 13
in position. The conduit 10 may act as the sleeve
through which runs an inner element by which tensile
compressive forces may be transmitted to a location
remote ~rom an operator. The conduit and inner
element thus form a cable such as is commonly used in
the actuation o~ automa~ic parking brakes and clutches.
- 5 -
8421
The moulded plastic termination member 11 has ~
cylindrical outer sur~ace and an internal surface which
intimately conforms to the exposed sur~ace of the part
of conduit 19that lies between the ends of the termination
member 11. The plastic not only circumscribes, and holds
in position relatively to each other,the widely spaced
turns of the outer layer 14 but also penetrates into the
interstices between adjacent turns o~ intermediate helix
13. This not only positions the turns of helix 13 but pro-
vides enhanced resistance to the passage o~ water or other
corrosive liqulds between the ends of the turns. Conduit
10 may be composed of galvanized steel w~re, and member 11
can be moulded from such flexible thermopla~tic
materials as nylon, acetal resin, or polyathylene.
The length of termination member 11 is more than
twice its diameter and is such thæt the member will
extend about a quarter of an inch beyond the end of a
~itting into which it is to be inserted to act as a
connection for the conduit. Such A ~ en~t~ t~nds to dis-
tribute vibration stresses along the part o~ the con-
dult that is covered by the termination member and thereby
relieve the concentration o~ stresses at the exit end
o~ the member.
- 6 -
~98421
The unit that has been described is farmed by use
o~ the mould~n$ apparatus that is shown in Fi~ure ~,
which provides a die 20, by ~bich a pair o~ cylindric~l
plastic termination members may be moulded simultaneously
one on the end o~ one conduit an~ the other on the
adjacent end o~ another condult that, initially, ~orms
an integral extension o f the ~irst conduit. The die
comprises two matin~ halves 21 and 22 definin~; a cylind-
rical cavity 23A, 23B, and 23C. The termination member
on the end of one conduit is $ormed within 23A and part
o~ 23B whilst th~ termination member on the other con-
duit is ~ormed within 23C and part of 23B, a cut beiDg
made throu~h the part 23B to separate the termination
members ~rom each other. The ends 24 and 25 o~ the die
are open to permit the two i~te~ral conduits to
extend through the mould, and, when the conduits are
in position, the ends of the cavity are closed by
sealing collars 27. One of the halves ~1 contains an
~ ~8
~ aperture ~ through which fluid thermoplastlc material
may be injected into the cavity. A particular suitable
material is a nylon copolymer that may be moulded at
a temperature o~ 460-500 F. and at a mnximum pressure
of about 215 pounds per square inch. In~ection time
~or such material is about three seconds, and cycle time
is about ten seconds.
- 7 -
51421
To use the apparatus 2Q the halves 21 and 22 are
separated ~nd the two inte~rally~connec~ed. c03du~ts a~e
brou~ht into position, with the sealin~ collars 27
lying at the ends of the mould. The mould is then
closed arou~d the eondu~s with the resilient end members
simultaneously sealin~ the ends and servin~ to centre
the ends o~ the conduits A conventional injeetion head
(not shown) is inserted into apertures 2~, and ~luid
plastic is injected into the cavity 23A, 23B, 23C into
intimate contact with the exposed surface of the outer
and intermediate lay~rs la and 13 and with the surfaces
o~ the cylindrical cævities ~3A, 23B and 23C. After
the plastie has cooled from the ~luid state, the halves
of the die are separated and the con~uits,still integrally
connected to each other, with the mouldin~ formed around
them are removed~ A cut is then made through the mould-
ing to sepærate the eonduits from each other to result
in two units eaeh eomprising ~ eonduit having a ter~.ihatioh
merAher fixed around its end portion.
The immediate product of the mouldin~ operation
is illustrated in Figure 3 which ~ows the struetura
30 moulded around the end portion o~ the eon~ui~ 10
that are still integrally connected to eaeh other. The
strueture 30 i~elud~scyli~drical portions 31A, 31B, and
31C corr~sponding to the parts 23A, 23B and 23C o~ the
10~8~2:1
cavity of the mould die ~0. rr`.lis structure is conveniently
cut into two æt thc~ reduced diame-ter portion 31~ using
a cut-off wheel, leævin~ t~o conduit ends terminæted
by termination men.bers llA and llC, as shown in ~i~ure 1.
Since the cut is mæde through a section o~ reduc~d
dir~eter, the bar res~ iin& ~rom the abrasive cut-off
is small.
It will be noticed that durin~ and throughout the
mouldin~ operation, the two conduits are integrally
connected together so that one ~orms an inte~ral
extension o~ the other. ~hus, each is e~fecti~e to
hold the strands o~ the other in their desired relative
position. ~he conduits are not separ&ted from each
other until the mouldin~ has set and becomes effective
to hold the turns in position relatively to each other.
II1 the embodiment described, each terminatin~ member is
effective to hold in position not onl-y the turn of
the outer læyel lg- but also the turn of the next inner
layer 13.
In typic~l use o~ a unit ~ormed as described, the
termination mem~er is inserterl into a fitting, such as
a screw machine or stamped bushin~ which is crimped down
84Zl
onto the ~rmination member. The crirmp~in~ operation
further enhances the liquid seal by forcefully
biasin~ the resilient plastic material into intimate
contact with the wires of intermediat~ helix 13.
-- 10 --
