U.S. patent number 3,824,681 [Application Number 05/347,848] was granted by the patent office on 1974-07-23 for method of providing a coupling for electrical connectors or the like.
This patent grant is currently assigned to The Deutsch Company Electronic Components Division. Invention is credited to Kenneth M. Clark.
United States Patent |
3,824,681 |
Clark |
July 23, 1974 |
**Please see images for:
( Certificate of Correction ) ** |
METHOD OF PROVIDING A COUPLING FOR ELECTRICAL CONNECTORS OR THE
LIKE
Abstract
A coupling ring is made rotatable around but axially fixed
relative to the plug shell of a connector, and provided with
bayonet grooves for receiving pins on the receptacle, the bayonet
grooves being given inner portions that fall within a radial plane
without forwardly inclined recesses at their inner ends. Selective
installation of spacer washers of various thicknesses for the
coupling ring, and bayonet pins of different diameters, enable the
coupling to properly position the plug relative to the receptacle
irrespective of manufacturing tolerances.
Inventors: |
Clark; Kenneth M. (Beaumont,
CA) |
Assignee: |
The Deutsch Company Electronic
Components Division (Banning, CA)
|
Family
ID: |
27374611 |
Appl.
No.: |
05/347,848 |
Filed: |
April 4, 1973 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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167317 |
Jul 29, 1971 |
3727172 |
|
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|
83782 |
Oct 26, 1970 |
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Current U.S.
Class: |
29/593; 29/434;
29/445; 439/314; 29/443 |
Current CPC
Class: |
H01R
13/424 (20130101); H05K 13/0447 (20130101); H01R
13/623 (20130101); B60G 15/02 (20130101); Y10T
29/49004 (20150115); H01R 13/4226 (20130101); Y10T
29/4984 (20150115); Y10T 29/49858 (20150115); Y10T
29/49861 (20150115) |
Current International
Class: |
B60G
15/02 (20060101); B60G 15/00 (20060101); H01R
13/623 (20060101); H01R 13/424 (20060101); H01R
13/62 (20060101); H05K 13/04 (20060101); H01R
13/422 (20060101); H01r 023/60 () |
Field of
Search: |
;29/628,206,434,443,445,593 ;339/89,90,91 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Lanham; Charles W.
Assistant Examiner: Walkowski; Joseph A.
Attorney, Agent or Firm: Carr; Richard F.
Parent Case Text
REFERENCE TO RELATED APPLICATIONS
This is a division of my copending patent application Ser. No.
167,317, filed July 29, 1971, for Electrical Connector, now U.S.
Pat. No. 3,727,172, which is a continuation-in-part of application
Ser. No. 83,782, filed Oct. 26, 1970, now abandoned.
Claims
I claim:
1. In an electrical connector having a first section and a second
section, said first section having a first shell, a first insert in
said first shell, said first insert having a first forward surface,
and a coupling ring rotatable around said first shell, said
coupling ring having a bayonet groove having a forward edge, said
coupling ring and said shell having opposed abutments, said second
section having a second shell, and a second insert in said second
shell, said second insert having a second forward surface, said
second shell having an opening through the circumferential wall
thereof for receiving a bayonet pin, the method of providing for
mating of said first section and said second section forward
surface in interengagement under predetermined compression
comprising the steps of
positioning between said abutments a washer having a predetermined
axial dimension so that said washer spaces said abutments apart by
said dimension,
then measuring the distance between said first forward surface and
said forward edge of said bayonet groove,
then if said distance is not within a predetermined range replacing
said washer with a second washer of a second predetermined axial
dimension such that said abutments are spaced by said second
predetermined dimension and said forward edge of said bayonet
groove is thereby repositioned to fall within said predetermined
range,
measuring the distance between the rearward surface of said opening
and said second forward surface,
and then fitting a pin into said opening such that said pin has a
portion projecting outwardly from said second shell for being
received in said bayonet groove and the portion of said pin so
projecting beyond said second shell is of predetermined lateral
dimension such that the distance from the rearward surface thereof
to said second forward surface is within a predetermined range.
2. The method as recited in claim 1 including the steps of
preparing a plurality of washers of different predetermined axial
dimensions,
and selecting said second washer from among said plurality of
washers.
3. The method as recited in claim 1 including the steps of
preparing a plurality of pins having portions of different
predetermined lateral dimensions adapted to project outwardly from
said second shell for being received in said bayonet groove,
and selecting said pin which is so fitted into said opening from
among said plurality of pins.
4. The method as recited in claim 3 in which
said plurality of pins are prepared to provide each with portions
of two diameters,
one of said portions of each of said plurality of pins being made
substantially complementary to said opening,
and the other portions of said plurality of pins being given
diameters different from one another.
5. The method as recited in claim 1 in which for measuring said
distance from said rearward surface of said opening and said second
forward surface of member substantially complementary to said
opening is extended therethrough and positioned adjacent said
second forward surface and the distance between said second forward
surface and the rearward edge of said member is measured.
Description
BACKGROUND OF THE INVENTION
1. FIELD OF THE INVENTION
This invention relates to electrical connectors.
2. DESCRIPTION OF PRIOR ART
Electrical connectors conventionally include a plug and receptacle.
In order to secure the plug and receptacle of the connector
together, a bayonet coupling mechanism frequently is used. This may
include pins projecting radially outwardly from the shell of one of
the sections of the connector, which are adapted to enter grooves
in a coupling ring provided on the other section of the connector.
The grooves have entrance portions at the forward end of the
coupling ring, from which the grooves extend inwardly, terminating
in recesses that extend back toward the forward end of the coupling
ring. The pins enter the bayonet grooves as the connector is moved
toward the mated position, moving to the inner ends of the grooves
as the coupling ring is rotated. The coupling ring is engaged by a
spring biasing it axially so that the bayonet pins are moved into
the recesss at the ends of the bayonet grooves upon the termination
of the rotation of the coupling ring. The spring force holding the
pins in the recesses acts as a detent that retains the coupling
ring against inadvertent rotation.
This arrangement means that the plug and receptacle are moved
toward each other a distance beyond their normal mated position
before the pins are allowed to enter the recesses at the ends of
the bayonet grooves. As the pins are moved into the recesses, there
is a slight separational movement of the connector plug and
receptacle. Also, it is possible for the coupling ring detent
spring to be overcome by an outward pull on the two sections of the
connector. This can allow some separation of the plug and
receptacle so that the contacts move relative to each other toward
an unmated position. Therefore, in order to assure electrical
continuity through the connector under all conditions, the pin and
socket contacts must be made sufficiently long to permit some
relative movement between them without causing disengagement.
Consequently, the connector must be made large enough to
accommodate the longer contacts, despite continued requirements for
reduction in the size and weight of electrical connectors.
SUMMARY OF THE INVENTION:
The present invention provides an improved electrical connector
which overcomes the difficulties outlined above. In this connector,
the coupling mechanism provides a secure bayonet connection, but
does not depend upon the bayonet pins and grooves to provide the
detent that holds the coupling ring against inadvertent rotation.
Instead, there is a separate detent for this purpose. Consequently,
the grooves in the coupling ring are made circumferential in their
inner portions, falling entirely in a radial plane and with no
recesses at their inner ends for receiving the bayonet pins. Thus,
when the coupling is moved to its mated position, the maximum
relative axial movement of the plug and receptacle takes place as
the bayonet pins enter the inner groove portions. Also, the
coupling ring is axially fixed relative to the plug shell, unlike
prior designs in which the coupling ring could be moved by
overcoming a spring force. Once the connector has been coupled, the
plug and receptacle are permitted no relative movement, so that
outward forces on the connector sections cannot cause separation of
the pins and sockets. Hence, the pins and sockets may be made quite
short because there is no overtravel as the connector is mated, nor
will the contacts be moved apart once the coupling has been
engaged. This allows the connector to be made smaller and lighter
than prior designs.
With no spring in the coupling mechanism, tolerances must be
controlled so that the insert faces engage with a proper amount of
compression. For the plug, a spacer washer is used to position the
coupling ring axially so that the forward edge of the bayonet
groove is a predetermined distance from the forward face of the
plug insert. Measurements are taken so that a washer of proper
thickness may be selected to accomplish the correct spacing between
the groove and the insert. For the receptacle, the distance between
the opening for the bayonet pin and the forward face of the
receptacle insert is measured. Then, a bayonet pin is selected of a
diameter such that its rearward surface is a predetermined distance
from the forward surface of the insert.
The detent for the coupling ring is provided by a leaf spring which
is held by the plug shell and has a central portion which is
adapted to enter a recess in the inner circumferential surface of
the coupling ring. This occurs when the coupling ring has been
rotated to where the bayonet pins are properly positioned at the
inner ends of the grooves. The spring is cammed out of the recess
for reverse movement in the unmating of the connector.
BRIEF DESCRIPTION OF THE DRAWINGS:
FIG. 1 is a perspective view of an electrical connector made in
accordance with this invention;
FIG. 2 is an exploded perspective view of certain portions of the
connector, including in particular the parts used for coupling the
plug and receptacle;
FIG. 3 is an enlarged longitudinal sectional view of the connector
in the mated position;
FIG. 4 is an exploded perspective view, partially broken away, of
the plug insert and shell;
FIG. 5 is a transverse sectional view taken along line 5--5 of FIG.
3;
FIG. 6 is a transverse sectional view taken along line 6--6 of FIG.
3;
FIG. 7 is a fragmentary sectional view taken along line 7--7 of
FIG. 5;
FIG. 8 is a fragmentary enlarged perspective view of one portion of
the plug insert assembly, illustrating the contact retention
fingers;
FIG. 9 is a fragmentary transverse sectional view taken along line
9--9 of FIG. 3;
FIG. 10 is an enlarged fragmentary view illustrating the details of
the finger shape and its engagement with the contact;
FIG. 11 is a fragmentary longitudinal sectional view showing the
retention finger spaced from the contact shoulder when the contact
is shifted forwardly;
FIG. 12 is a further enlarged fragmentary view illustrating the
engagement between the retention finger and the contact shoulder,
with the contact under rearward load;
FIG. 13 is an enlarged fragmentary longitudinal sectional view of
the forward portions of the inserts of the plug and receptacle,
shown slightly separated and illustrating the sealing arrangement
for the openings;
FIG. 14 is a fragmentary flat pattern of the inside of the coupling
ring, showing one of the bayonet grooves;
FIG. 15 is an enlarged fragmentary sectional view taken along line
15--15 of FIG. 3, illustrating the engagement of the spring tab on
the snap ring and the forward end of the receptacle shell;
FIG. 16 is a fragmentary longitudinal sectional view of the
connector incorporating one size of bayonet pin and spacer washer
used in adjusting tolerances to assure proper engagement at the
forward surfaces of the connector inserts;
FIG. 17 is a view similar to FIG. 16, but with different sizes of
bayonet pin and spacer washer;
FIG. 18 is a fragmentary longitudinal sectional view of the plug
showing the critical dimension between the edge of the bayonet
groove and the forward face of the insert;
FIG. 19 is an enlarged fragmentary sectional view showing how the
spacer washer controls the dimension between the edge of the
bayonet groove and the insert face in different tolerance
conditions;
FIG. 20 is a fragmentary transverse sectional view of a group of
three different sized spacer washers, one of which is to be
selected in properly spacing the forward edge of the bayonet
groove;
FIG. 21 is a fragmentary longitudinal sectional view of the
receptacle illustrating the manner of measuring to obtain the
dimension from the opening for the bayonet pin to the forward face
of the insert;
FIG. 22 is a side elevational view of two bayonet pins having outer
ends of different sizes;
FIG. 23 is a fragmentary longitudinal sectional view of the
receptacle shell and bayonet pin showing how different sizes of
bayonet pins may be used in different situations to in both cases
position the rearward edge of the pin at the same location; and
FIG. 24 is a fragmentary elevational view of the receptacle shell
and bayonet pin of FIG. 23.
DESCRIPTION OF THE PREFERRED EMBODIMENT:
Illustrated in the drawing is a multiple pin and socket connector
that includes a plug 9 and a receptacle 10. The general arrangement
for retaining the contacts is the same in the plug and receptacle.
In the embodiment illustrated, the pin contacts are in the plug and
the socket contacts in the receptacle although this may be reversed
if desired. The plug 9 includes a plug shell 11, which is a
generally tubular metal member of circular cross section. Within
the shell 11 is an insert assembly 12 that serves to retain and
hold a plurality of pin contacts 13. The insert assembly 12
includes disks 14 and 15 of a substantially rigid plastic. A
suitable material for these members, because of its strength and
temperature resistance, is a polyarylsulfone marketed under the
trademark "Astrel" 360 plastic by Chemical Division, 3M Company, 3M
Center, St. Paul, Minnesota. The disks 14 and 5 are suitably bonded
together at their mating radial faces. At the forward end of the
insert assembly 12 is bonded a gasket disk 16 of a resilient
elastomeric material, such as silicone rubber.
The insert assembly 12 is retained in the plug shell 11 by means of
interengaging castellations on the insert assembly and the plug
shell. For this purpose, there are circumferentially extending
plugs 18 that project outwardly from the periphery of the rearward
disk 15, as seen in FIG. 4. In the embodiment illustrated, there
are five of the lugs 18. The circumferential surface 20 from which
the lugs 18 project is substantially complementary to the inner
surface 21 of the plug shell 11. The slots 22 are made sufficiently
wide to permit the insert assembly 12 to be introduced into the
plug shell 11 by being slid inwardly from the forward end 23 of the
plug shell, with the lugs 18 passing through the slots 22. The
insert assembly 12 is moved into the plug shell until the rearward
radial edges 25 of the lugs 18 are brought into engagement with an
annular shoulder 26 at the rearward portion of the plug shell.
Circumferential slots 27 are formed at the rearward portion of the
inner surface 21 of the plug shell 11, and are of widths
substantially equal to the widths of the lugs 18. This provides
circumferentially extending shoulders 28 spaced opposite from the
annular shoulder 26 of the plug shell. The shoulders 26 and 28 are
spaced apart a distance corresponding to the dimensions of the lugs
18 longitudinally of the insert assembly 12. This allows the insert
assembly 12 to be rotated after the rearward edges 25 of the lugs
18 have been brought into engagement with the annular shoulder 26.
The rotation of the insert assembly brings the lugs 18 in back of
the circumferential shoulders 28 and into the circumferential slots
27. This positions the forward edges 29 of the lugs adjacent the
circumferential shoulders 28 so that the radial shoulders 26 and 28
of the plug shell 11 hold the insert assembly 12 against
longitudinal movement relative to the plug shell.
One of the lugs 18 may include a longitudinally forwardly
projecting portion 31 having a side edge 32 which is brought into
engagement with the side edge 33 of one of the longitudinal slots
22 in the plug shell for thereby limiting the rotational movement
of the insert assembly 12 (see FIGS. 4 and 7). When the forward
projection is provided, it assures that the insert assembly 12
assumes the proper rotational alignment relative to the plug shell.
After being properly positioned in the plug shell 11, the insert
assembly is locked in place so as to prevent it from being given
reverse rotation. This may be accomplished by bonding the insert
assembly to the plug shell.
With the insert assembly positioned in this manner, a rearward
sealing element 35 made of a resilient elastomer, such as silicone
rubber, is bonded to the rearward radial face of the insert
assembly and to the rearward portions of the inner circumferential
wall 21 of the plug shell.
The pin contacts 13 are received in spaced parallel openings 38
formed in the insert assembly 12. The openings 38 are continuous
from the front to the rear of the insert assembly 12, and are
separated from each other so that there is no communication from
one opening 38 to the other. The connector is designed so that a
large number of pin contacts 13 may be retained in close adjacency,
but, for clarity of illustration, only a relatively few such
contacts are shown in the drawing.
Each opening 38 includes a relatively wide-diameter portion 39 at
the rearward end of the plastic disck 15 which, through a
frustoconical portion 40, tapers forwardly to a portion 41 of
smaller diameter. A plurality of fingers 42 extends radially
inwardly and axially forwardly from the portion 41 of the opening
38 into the continuation 43 of the opening 38 in the member 15.
This positions the fingers 42 inwardly and radially opposite the
circumferential wall of the portion 43 of the opening 38. The
fingers 42 are shorter than the section 43 of the opening, so that
their forward ends are inward of the forward radial face 44 of the
member 15. There are four of the fingers 42 in the example shown,
as illustrated in FIG. 8. The fingers 42 are rounded transversely
so that collectively they define a generally frustoconical shape
with narrow spaces between adjacent fingers. While the plastic
member 15 is relatively hard and rigid, the fingers 42 are thin
and, therefore, resilient. A radial shoulder is formed by the
rearward face 45 of the member 14 where the diameter of the opening
decreases at portion 46. In the gasket member 16, the opening has a
relatively wide-diameter portion 47 at the rearward end and a
smaller-diameter portion 48 at the forward end.
An opening 49 in the rearward sealing member 35 communicates with
each of the openings 38.
The pin contacts 13 may be of conventional construction, including
hollow, longitudinally elongated barrel portions 50 at their
rearward ends, which receive the ends of wires 51 from which the
insulation has been stripped. The contact barrels 50 are crimped to
the wires 51 to form a mechanical and electrical connection. The
wires 51 enter the openings 38 through the openings 49 in the
rearward member 35, being engaged by annular sealing beads 52
formed on the circumference of the opening 49.
Forwardly of the barrel portion 50, each contact 13 includes a part
53 of enlarged diameter which defines forward and rearward
shoulders 54 and 55, respectively. Beyond the forward shoulder 54,
the contact narrows to a projecting pin portion 56 that is adapted
to enter the socket contact. When installed in the opening 38, the
forward shoulder 54 of the contact is adjacent the rearwardly
facing shoulder defined by the rearward face 45 of the insert 14,
which thereby prevents forward movement of the contact 13.
In this manner, the contact is positioned within the insert
assembly and securely retained. With the use of the integral
fingers 42, it is unnecessary to provide any auxiliary metal clip
for retaining the contact, as in conventional connector
construction. This simplifies the manufacture of the connector and
lowers its cost. The danger of an improperly installed retainer
clip is obviated. With the fingers 42 being entirely received in
the section 43 of the opening 38, which locates them rearwardly of
the forward face 44 of the disk 15, the bonding together of the
inserts 14 and 15 will not adversely affect the fingers. In other
words, the fingers are remote from the bond line so that any excess
bonding material squeezed out at the joint will not interfere with
the movement of the fingers.
As best seen in the enlarged illustration of FIG. 10, the fingers
42 are thicker in cross section at their forward ends than they are
at their points of attachment to the insert 15, being tapered
gradually in thickness to the rear. Also, each finger has a
substantially radial forward end surface 57 which connects at a
right angle to an inner end surface 58, which is a cylindrical
segment generally complementary to the barrel 50 of the contact 13.
When the finger 42 engages the contact 13, the radial end surface
57 fits behind the rearward shoulder 55 of the contact, while the
inner end surface 58 of the finger rests upon the barrel 50
adjacent the shoulder 55.
The rearward transverse shoulder 55 of the contact 13 does not fall
within a radial plane. Instead, it is inclined toward the forward
end of the contact. Consequently, the shoulder 55 is undercut,
being defined by a frustum of a cone. Desirable results are
achieved when the shoulder 55 is inclined at around 12.degree.
relative to a raidal plane. When the contact 13 is subjected to a
force pushing it toward the rear, the undercut shoulder
configuration and the inner finger surfaces 58 contribute greatly
to the amount of force which can be absorbed before the retention
fingers 42 will fail.
With the arrangement of this invention, the fingers 42, loaded as
columns, receive the forces on them near the neutral centers of the
columns, minimizing the tendency to buckle. The plastic of the
fingers 42, being softer than the metal of the contact 13, becomes
distorted where it engages the radially outer portion of the
shoulder 55, as illustrated in particular in the enlarged view of
FIG. 12. This has the effect of embedding the shoulder in the outer
ends of the plastic fingers 42, stabilizing the finger ends. This
increases the column strength of the fingers 42 because a column
can withstand more loading if its ends are stabilized.
An additional stabilizing effect is realized because of the arcuate
inner surfaces 58 of the fingers 42 substantially complementarily
engaging the periphery of the barrel 50 of the contact adjacent the
base of the shoulder 55. This helps to anchor the free ends of the
fingers. The inclined configuration of the shoulder 55 results in a
force component on the fingers 42 helping to hold the surfaces 58
tightly against the circumference of the barrel 50 to enhance the
column stabilizing effect.
The greater wall thickness of the fingers at their outer ends adds
to their strength in shear and in bending. The bending strength
resists the buckling of the fingers under load.
Another advantage comes from the fact that the inner corner 59 of
the finger 42, between the end surface 57 and the inner surface 58,
becomes spaced rearwardly from the fillet 60, which necessarily is
formed between the shoulder 55 and the barrel 50 when the contact
13 is machined. When there is a straight radial shoulder, the inner
corners of the retention fingers will engage the fillet at the base
of the shoulder. This deflects the fingers outwardly, thereby
tending to cam the fingers out of engagement with the shoulder. The
undercut shoulder 55 permits the finger to clear the fillet 60
without requiring a recess in the finger and without sacrifice in
the strength of the fingers.
The insert assembly 61 for the receptacle 10 includes a plastic
disk 62 that is similar to the member 15. To it is bonded or
otherwise suitably secured a forward cover disk 63. The members 62
and 63 also may be made of "Astrel" 360 plastic. Outwardly
projecting lugs 64 on the disk 62 correspond to the lugs 18 on the
member 15. The lugs 64 secure the insert assembly 61 to the
receptacle shell 65 in the same way that the lugs 18 attach the
insert assembly 12 in the plug shell 11. The insert assembly 61 is
introduced into the receptacle shell 65 by passing the lugs 64
through axial grooves in the inner surface of the receptacle shell
65, whereupon subsequent rotation of the insert assembly 61 places
the lugs 64 between opposed forward and rearward shoulders 66 and
67, respectively, in the receptacle shell. This holds the disk 62
and the cover element 63 within the receptacle.
The socket contacts 68 are retained in continuous separate openings
69 in the insert assembly of the receptacle, positioned against
axial rearward movement by integral fingers 70 that project
forwardly and inwardly from the insert disk 62. A shoulder 71 on
the insert member 63, where the opening 69 reduces in width, is
adjacent the forward end of the contact 68 and precludes forward
movement of the contact. The fingers 70 are engageable with the
rearward edge of the annular enlargement 72 on the socket contact.
A wire 73 extends inwardly through an opening 74 in the rearward
sealing member 75 of the receptacle 10 for each of the socket
contacts 68. The end portions of the wires 73 are stripped of
insulation and connected by crimping to the rearward barrel ends 76
of the socket contacts 68. When the forward ends 77 of the socket
contacts receive the projecting pin portions 56 of the pin contacts
13 upon the mating of the connector, circuits are completed between
the wires 51 and 73.
A rounded annular bead 78 projects outwardly from the forward
radial face 79 of the cover disk 63 of the receptacle insert around
each of the openings 69. The bead 78 is engaged by the flat forward
face 80 of the gasket 16 of the plug 9 when the connector is in the
assembled position. Consequently, the bead 78 displaces the
resilient material of the gasket 16 and an efficient moisture seal
is produced. This type of seal does not rely upon the entry of a
projecting part of the resilient elastomer into a recess in the
hard plastic of the mating part as in some prior-art designs.
Unlike the previous designs, swelling of the gasket 16 from attack
of fluids will not appreciably interfere with the mating of the
connector so that the axial force required will not vary
significantly under those conditions.
The mechanism for securing the plug and receptacle together in the
mated position includes a coupling ring 81 that circumscribes the
plug shell 11. The rearward end of the coupling ring includes a
radially inwardly extending flange 82 in back of a rearwardly
facing shoulder 83 on the plug shell. A snap ring 84 fits in an
annular recess 85 in the intermediate portion of the inner
circumferential wall of the coupling ring 81. The snap ring 84 is
positioned in front of a forwardly facing radial shoulder 86 on the
plug shell 11, cooperating with the flange 82 in retaining the
coupling ring 81 in the plug shell 11. This allows the coupling
ring 81 to rotate relative to the plug shell 11, but relative axial
movement is prevented.
Intermediate the snap ring 84 and the flange 82, the coupling ring
81 is provided with three short, arcuate, longitudinally extending
recesses 87 in its inner surface 88 (see FIGS. 2 and 5). These
recesses are adapted to receive the outer rounded portion 89 of a
leaf spring 90. The latter member has normally straight legs 91
terminating in an inwardly bent end 92 which is received within a
radial opening 93 in the periphery of the plug shell. This holds
the spring 90 to the plug shell 11. Adjacent the legs 91 of the
spring 90 are flat chordal surfaces 94 which provide a clearance
for permitting flexure of the spring 90.
By this construction, the coupling ring 81 can be rotated relative
to the plug shell 11, but there is a detent action tending to
prevent relative rotation when the portion 89 of the spring 90
enters a recess 87. This retaining force may be overcome by
applying adequate torque to the coupling ring to cam the rounded
spring portion 89 out of the recess 87, compressing the spring
inwardly and allowing the spring portion 89 to slide along the
circumferential surface 88 of the coupling ring intermediate the
recesses 87.
Forwardly of the snap ring 84, three bayonet grooves 95 are formed
in the inner circumferential surface 88 of the coupling ring. Each
groove 95 includes a wide entrance opening 96 at the forward end 97
of the coupling ring, from which there extends an inclined portion
98 of the groove, leading to a circumferential inner part 99 of the
groove. The axis of the latter portion of the bayonet groove 95, as
best seen in FIGS. 2 and 14, falls entirely within a radial plane
as there is no recess for the bayonet pin at the inner end 100 of
the groove.
The receptacle shell 65 includes a forward portion 101 of enlarged
diameter which provides a clearance around the insert assembly 61.
At the end of the forward portion 101 of the receptacle shell are
three radially outwardly projecting bayonet pins 102.
When the electrical connector is to be mated, the forward end
portion 103 of the plug shell 11 enters the forward portion 101 of
the receptacle shell 65, fitting in the clearance space around the
insert assembly 61 of the receptacle. Keys 104 on the plug shell
fit in keyways 105 in the receptacle shell, assuring the proper
rotational alignment of the plug and receptacle. With the keys in
the keyways, the detent spring, when in a recess 87 in the coupling
ring, positions the coupling ring so that the entrances 96 of the
bayonet grooves 95 are aligned with the bayonet pins 012.
Therefore, the bayonet pins 102 are brought to the entrances 96 of
the bayonet grooves 95 in the coupling ring 81 as the plug and
receptacle are advanced axially toward each other. Subsequent
rotation of the coupling ring 81 moves the bayonet pins 102 through
the inclined portions 98 of the grooves 95 and into the
circumferential portions 99, drawing the plug and receptacle into
the fully mated position. The coupling ring 81 is turned until the
pins 102 are adjacent the inner ends 100 of the grooves 95, which
occurs as the outer portion 89 of the spring 90 enters a detent
recess 87 in the coupling ring.
A positive stop is provided in one of the bayonet grooves to
prevent rotation of the coupling ring 81 past the detent position
when the connector is mated. This is accomplished by bending
inwardly a small section 106 of the circumferential wall of the
coupling ring, presenting an abutment surface 107 in the bayonet
groove where it can be contacted by the bayonet pin at the
termination of the rotation of the coupling ring 81 (see FIG. 6).
This location corresponds to the positioning of the outer portion
89 of the detent spring 90 in a detent receptacle 87. An opening
108 is formed in the wall of the coupling ring adjacent the stop
107, while two additional openings 109 in the coupling ring are
spaced 120.degree. from the opening 108. This permits visual
exterior inspection of the connector when in the mated position to
ascertain whether or not the bayonet pins 102 have moved a
sufficient distance into the bayonet grooves 95. When the ends of
the pins 102 (which may be painted) can be seen through the
openings 108 and 109, it is known that the bayonet pins are in the
inner portions of the bayonet slots and that the plug and
receptacle are coupled properly.
By this arrangement, the plug and receptacle are advanced axially
toward each other the maximum distance when the bayonet pins are
adjacent the ends 100 of the grooves 95 that receive them. No
outward movement occurs as the connection is made, and, when the
bayonet pins 102 reach the circumferential portions 99 of the
grooves 95, the parts are held in their position of full maximum
engagement. Even though subjected to a separating force, no
relative movement of the ;ug and receptacle can take place, so that
electrical continuity through the contacts is assured. The bayonet
pins 102 are held against the forward sides of the bayonet grooves
95 when separating forces are imposed, while the coupling ring 81
is prevented from movement axially by the engagement of the flange
82 with the rearwardly facing shoulder 83 of the plug shell 11.
This provides a solid connection of the parts.
When the connector is in the fully mated position, the forward
outer periphery of the forward end of the plug shell 11 engages an
annular seal 110. The latter member is held in an annular groove
111 in the receptacle shell 65 by bonding.
In some instances, the snap ring 84 may be provided with forwardly
projecting tabs 113 that are brought into engagement with the end
of the forward portion 101 of the receptacle shell 65 when the
connector is mated (see FIG. 15). This puts a desirable tension on
the coupled plug and receptacle, eliminating any clearance in the
coupling mechanism. This also makes an electrical connection
between the plug shell 11 and the receptacle shell 65.
The plug and receptacle are disconnected by reverse rotation of the
coupling ring 81 to free the bayonet pins 102 from the bayonet
grooves 95. As this is accomplished, the detent spring 90 is forced
out of one detent recess 87, and its central part 89 slides along
the surface 88 of the coupling ring 81 to the next detent recess
87. In the latter detent position, the bayonet pins 102 have
reached the entrances 96 to the grooves 95 and the plug and
receptacle may be pulled apart axially.
When the connector is mated, the plug 9 and the receptacle 11 are
held together by the reaction of the rearward surfaces of the
bayonet pins 102 against the forward edges of the bayonet grooves
95. This causes the forward faces of the inserts in the plug and
receptacle to be brought into interengagement and held under
compression. When assembled properly, the sealing bead 78 engages
and becomes embedded in the forward face 80 of the resilient insert
16 around the mating pin and socket contacts. It is important that
the bead 78 of the forward cover disk 63 and the forward face 80 of
the insert 16 assume the proper relative position when the
connector is mated. If they are advanced toward each other an
inadequate distance, the bead 78 will not bear against the gasket
disk with sufficient force to form a seal. Too much movement of one
insert toward the other will cause overcompression at the mating
connector surfaces, making it difficult to mate the plug and
receptacle. While some variation is not harmful, manufacturing
tolerances can build up so that either objectionable condition can
exist.
In conventional connector design, where there is a spring in the
coupling mechanism, dimensional variations of this sort are not
important because the movement permitted by the spring will allow
for tolerances and keep the mating faces under proper compression.
With the present invention, however, there is no spring in the
coupling mechanism, and tolerance buildup requires a different
solution. This is accomplished by controlling the positions of the
working surfaces of the bayonet grooves and the bayonet pins
relative to the forward surfaces of their respective insert
assemblies. Each is controlled separately to a predetermined
dimensional range.
For the coupling ring 81, tolerance control is effected by means of
a spacer washer 115 which fits between the abutments defined by the
rearward flange 82 of the coupling ring 81 and the shoulder 83 on
the shell 11 (see FIGS. 16-20). By selecting a spacer washer 115 of
proper axial dimension, the distance A (indicated in FIG. 18)
between the forward edge 116 of the bayonet groove 95 and the
forward face 80 of the gasket insert 16 can be held within
acceptable limits. Normally, in a carefully manufactured connector,
the distance A can be controlled adequately by having available
only a limited number of sizes of the spacer washers 115. Three
such washers, such as the washers 115a, 115b and 115c shown in FIG.
20, will suffice.
In the assembly procedure, the coupling ring 81 is positioned on
the shell 11 with one thickness of washer, selected by estimation
or arbitrarily, positioned between the flange 82 and the shoulder
63. The distance A then is measured. Obviously, if the selected
washer causes the distance A to fall within the proper range,
nothing more need be done. However, if the distance A is over or
under the specified range, the originally chosen washer is replaced
by one of a thickness such that the distance A will be brought to
within proper limits. Simple addition or subtraction will establish
the choice of spacer washer. A thicker washer will move the forward
edge 116 of the groove 95 closer to the surface 80, and a thinner
washer will increase the distance between the forward edge 116 and
the surface 80.
In the receptacle 10, it is necessary to maintain the correct
distance B between the rearward working surfaces of the bayonet
pins 102 and the forward edge of the bead 78 (see FIG. 21). This is
accomplished by providing bayonet pins 102 with different diameters
at their exposed portions, permitting selection of a bayonet pin of
proper size. This may be a choice from among two pins, such as the
pins 102a and 102b illustrated in FIG. 22. In each instance, the
shank portion 117 is the same and can fit complementarily in the
opening 118 in the shell 65. However, the enlarged outer parts 119a
and 119b which are adapted to fit in the bayonet groove 95, are of
different diameters.
In selecting the proper bayonet pin, the distance C is measured
from the rearward edge of the opening 118 in the receptacle shell
65 to the forward edge of the bead 78. With this distance being
known, it is possible then to select the bayonet pin having its
outer part 119a or 119b dimensioned so as to result in a distance B
within accepted limits. Obviously, when the distance C is at a
minimum, the bayonet pin with the smaller outer end 119a is
selected, while larger distances C require the bayonet pin having
end 119b.
Because the opening 118 and the forward face 79 of the receptacle
insert are radial with respect to the connector, the distance C may
be found by first inserting a rod 120 through the opening. The rod
20 is extended inwardly parallel to the forward face 79 of the
insert 63. A measurement can be made without difficulty between the
rearward edge of the rod 120 and the forward edge of the sealing
bead 78. This is the same dimension as that between the rearward
edge of the opening 118 and the bead 78, which is the distance
C.
The foregoing detailed description is to be clearly understood as
given by way of illustration and example only, the spirit and scope
of this invention being limited solely by the appended claims.
* * * * *