Note: Descriptions are shown in the official language in which they were submitted.
~ ~6Z,'7~
This invention relates to electrical connectors.
A typical application ~or an electrical connector is to
connect a radio operator's headset to his radio equipment. Other
applications in the same general field include connecting a power
supply to other equipment, connecting a man-pack radio set o~ low
power into a base station radio set o~ greater power, installing
equipment into a vehicle and connecting crew headsets into a ve-
hicle intercommunications system. Connectors naturally have appli-
cations in wider ~ields also.
A problem exists in con~licting needs for standardiza-
tion o~ connectors and ~or connectors having different operational
characteristics. Thus, to take one example, a single organiza-
tion will want to have a single kind o~ receptacle connector part
on all its communications eq~ipment ~or receiving the connector
parts attached to the headsets or to the handsets o~ the users of
that equipmentO Any user can then "plug-in" to any item o~ commu-
nications equipment. But dif~erent users have different opera-
tional require~ents, and while some users need a snatch-release
connection others need a more securls, push-pull connection. In
general where a ~an is carrying his own equipment a secure con-
nection is required while a snatch release is required for con-
; nection to stationary equipment or to mobile equipment carried:: ..`
by a vehicle or by a different man~
Both types o~ behavior (push-pull and snatch-release)
should be possible from a single receptacle-part using suitable
~, di~ferent plug-parts. This invention provides an electrical
connector comprising two parts, a ~irst part having a circumfe-
rentially-disposed, radially-resilient independent retaining ring
captive therein and a second part having a circum~erentially-dis-
posed retaining projection, the resilience o~ the independent re- ;-
taining ring permitting the parts to be mated and separated by
radial distortion of the ring without distortion of the first part
~ ', "' ':
., ,~ i -- 1 --
71~6
as it passes -the said retaining projection during mating and se-
paration~
In a ~irst aspect the connector is a snatch-release
connector. In this aspect the retaining ring of the first part
has a release cam surface which is so pressed against $he retain-
ing projection of the second part when the parts are mated that
to separate the parts a longitudinal separating force must be .
applied which is suf~icient to cam the release cam sur~ace radial-
ly over the retaining projection against the resilience of the
10 retaining ringO
In a second aspect the connector is a push-pull connec- ~-
tor. In this aspect the retaining ring is captive within a lock- -
ing member which is mounted on the remainder of the first part
for longitudinal movement therealong and which has a camming sur-
face for radial camming of the rin~r; and the second part has a
stop behind its retaining projection arranged to engage the ring
during mating whereby the longitudinal movement of the ring is
stopped while the locking member continues to move and hence en-
gages its camming surface with the ring to cam the ring radially
into such a position between the stop and the retaining projec-
tion that separation o~ the parts is prevented unless the lock-
ing member is moved in the separation direction to disengage its
camming surface from the ring allowing the ring to deform radially
and so pass over the retaining projection.
. .:
;The radially resilient retaining ring is preferably
..made ~rom a split ring of plastics material having suitable cam
.-, profiles and a sti~ening split ring o~ metal to give the requi-
;~, red resilient properties. .
~ Embodiments of the invention are now described
:
-`~' 30 ~
' ' '"'~'
. ~'.`d 2 _
~627~3/6
,
with reference to the accompanying drawings in which:-
Figure 1 is a partially cut away side view of a
snatch release ConneCtOr in a separated position;
Figure 2 is a view similar to Figure 1 showing
the connector in a mated position;
Figure 3 is a cross-section of a retaining ring;
Figure 4 is a graph of separation force required
against angle ofa~plication of the force for various
different retaining rings;
Figure 5 is a partially cut-away view similar
to Figure 1 of an unmated push-pull connector; and
Figure 6 is a view similar to Figure 5 showing
the push-pull connector mated.
.
The connectors shown in Figures l and 2, and 5 `
and 6 are known in the art. An identical receptacle
comprising a tubular nose 40 with a raised rim 41 next to
a groove 42 is used throughout. The groove 42 has a
forward wall 43 constituting a locking projection and a
backward wall 44 constituting a stop. The nose 40 slopes
.::
` 20 inwardly from the rim 41 to the front of the nose 40 (i.e.
to that portion which is nearest to the other connector
,, i .
part ~ust before mating). Inside the nose 40 there is a
` tubular hole for receiving the other part and ele~trical `~
~- contacts (not shown) for making the electrical sonnec~
tions between the parts~
~`~ The inner portion of the free plug part 10 is
also identical in all the embodiments described. The
~, ;.:.~`~l forward end ~i.e. the end which is closest to the othPr
part ~ust before mating~ of the plug part 10 is in the
~,j 30 shape of a tube 12 which is recelved inside the nose 40.
~`, Splines 13 (only one shown) flt in ~atching slots in the
1 nose to ensure that the electrical contacts of ~he two
"
~ parts are correctly aligned on mating. Towards the rear
: . .
-3~
.'', `~ "''~'.
~L~Çi,Z7~
end of the plug part 10 there is an annular collar 14 to
which a sleeve 15 is attached and at the rear end the
plug part 10 has a threaded portion 16 for connection to
cable gripping means (not shown~. The plug part 10 and
- the receptacle part move iDto and out of connection with
one another along an axis 11.
The external profile of the sleeve 15 is the
same in all the embodiments described having circumfer~
entially-extending ridges 33 for a user to grip on to.
Naturally various different patterns of ridges can be de- ;
vised to signify different types of coupling but such a
scherne is not shown here. The sleeve 15 is mounted on
the annular collar 14 of the plug part 10. There is a
`:
~` circumferential groove 30 which extends round the inside
`~ of the sleeve 15 near to its rear end which receives a back
stop 29 to prevent the sleeve lS from sliding forwardly
off the plug part 10. During a~;sembly the sleeve 15 is
.
slid backwardly into position over the annular collar 14
;`, and the back stop 29 is wound into the groove 30 to keep
.~
the parts assembled. At the forward end of the sleeve 15
. ~ .
there is an inside chamfered portion 34 to act as a
nose-receiving guide during mating.
The embodiments shown differ in the configuration
of the inside surface of the sleeve 15 and in the disposition
, .,~ . .
of locking or retaining members within the sleeve 15.
Referring to Figures 1 to 4 a snatch~release
i connector has its sleeve 15 retained against longitudinal ;
movement over the plug part 10 by virtue of having a thicker
, wail than other types of sleeve lS providing a step 50
- ~ 30 against the forward side of the collar 14. The collar 14
~ is thus gripped on both sides and no significant longi-
.
~-' tudinal movemen~ of the sleeve 15 is possibleO
3ehind the front chamfered guide portion 34 there
-
' `'' ' ' '
` -4-
. ,~
~al627~i
is a circumferential groove 52 in the inside surface of
the sleeve. This groove 52 holds a retaining rirlg 60 and
restrains it against significant forward and backward
movement. The ring 60 is made of a plastics type material
split-ring 62 backed up by a metal split-ring 64. The
inner surface of the ring 60 is profiled with two cam sur-
faces. A leading cam surface 61 is a simple cham~er for
engaging the chamfer on the front of the nose 40. As the
two parts are mated the interaction between the leading
cam surface 61 and the nose 40 expands the ring 60 radially
so that it goes over the rim 41a The leading cam surface
61 is followed by a much longer trailing cam surface 63.
The trailing cam surface 63 consists of a short tubular
portion 65 opening out to a relatively long portion 66 with
a slope and ends with a curved portion 67 which blends the
sloped portion 66 into the back of the ring 60.
, Positive engagement of the parts on mating is
achieved by the trailing cam surface 63 squeezing the rim
, 41. An important operational feature is that when fully
..~,
mated the rim 41 bears a~ainst the curved portion 67 of
the trailing cam surface 63. This ensures that a continu-
ous engagement pressure is maintained while the parts are ~
mated and also this ensures that the parts can be separ- ~ -
ated by an axial pull. The trap to avoid is letting the
`~ ring 60 drop into the groove 42 behind its forward wall 43.
S The plastics split ring 62 can be made o~ an
acetal resin (DuPont~s Delrin 500) which has properties
similar to those of nylon but with improved performance in
~,~ respect of creep and in the face of adverse chemicals such
as cleaning fluids or fuels.
As a manufacture and assembly aid it is provid=d
with three pips 69 on its front edgeO These assist in -
, putting the ring 60 the righ~ way round into the groove 52.
,, ' . ' ''
~1i~Je P~4rk
~. 1 ~5_ .~
:~ .
106~
If the ring is put in back eO front it drops behind the
rim 41 on mating and the two parts of the connector are
trapped together.
A radially oriented slot is cut in the ring 62
to split it~ The outer rim of the plastics ring 62 has
a circumferential groove 68 for accommodating the split
ring 64.
The ring 64 can be made of stainless steel. A
portion of the circumference is removed from the ring to
split it and the gauge of the ring is chosen according to
- desired performance of the ConneCtOr. For a separating
snatch force of between 4 and 6 kgf over a range of angles
from directly in line to 20 out of line a wire of 0.043'
diameter is preferable.
This can be seen in Figure 4 where the x-axis
is the snatch force required (in kgf) and the y-a~is is
the out of line angle in degrees. The curve 70 shows the
;~ force required to separate the connector parts when the
retaining ring is not used. This force is almost entirely
made up of friction between the electrical contacts. The
curves 71~ 72 and 73 show the eff~ct of using a retaining
ring with 0.035~, 0.0433 and 0.048'3 diameter wires respec-
- tively while the curve 74 shows the effect of using the
,~ plaseics ring 62 on its own. It is interesting to observe
3 that without a wire the plastics ring 62 is too soft for
~;~ in-line pulls but is too stiff for out-of-line pulls.
Referring to Figures 5 and 6 a push~pull con-
nector is shown made of a generally similar construction
~; to the snatch connector described above. A split ring 80
of smaller cross-sectional size than the ring 60 is held ~ -
in slot 82 in a grip 81 mounted fast with the body of the
plug part 10. In its unstressed state the ring 80 expands
to substantially fill ~he slot 82.
~6-
, ~ .
... . ..
1~6~:78~
It is large enough to go over the rim 41 of the nose 40
with only minimal further expansion. The grip 81 at its
forward end and the slot 82 are divided into a plurality
of forwardly extending fingers between which are located
cam members 83 which extend radially inwards from the sleeve
15 which is longitudinally slidable for push-pull locking.
The innermost ends of the cam members 83 are dimpled to
engage a wire 84 in the ring 80 and provide a definlte
restraining "feel" in the lo~ked position of the connector.
In the unmated position the outward bias of the
ring 80 presses against the leading edge of the cam members
83 and holds the sleeve at the rearward end of its travel
until the parts are properly engaged in the mating position.
Then the plug part 10 can move no further forward and a
push on the sleeve 15 cams the rimg 80 inwardly until it
ls well fixed behind the rim 41. The dimples of the cam
members engage and hold the sprin~ wire 84 preventing the
sleeve from sliding backwards accidentally. The coupling
; is secure against a pull on the cable since the slot 82
holds the plug part 10 against the! ring 80 which is itself
fast against the rim 41.
To release the connector the sleeve 15 is pulled
back al~owing the ring ô0 to expand and pass over the rim 41.
Various modifications of the scheme shown can be
devised. In one modification the camming members 83 and
.: .
the fingers of the grip 81 are made to follow a generally
helical course. Then the push to lock action requires a
twist as well. This can be made to feel like a bayonet
fitting to a user accust ed to bayonet fittings even though
no bayonet pins are used. A resistance against the twist
is supplied by the splines 13 engaging in the nose 40.
Other arrangements of split ring may be used,
, . .
e.g. the wire 84 need not be proud, the wire could be on
~7~ r.
~6Z~6
the inside instead of on the outside and the wire could be
omitted altogether since the degree of resilience required
for the push-pull arrangement is less restrictive than for
the snatch-release one.
-8- - -
.. . ..
.i ," ~ " , ~ , ~ ,, ,, , ~, " ,
