Electrical connector having opposed locking ramp members

An electrical connector comprising a hollow first connector body housing electrical connector blades and adapted to receive a hollow second connector body housing electrical contacts for receiving the connector blades. Blade insertion and withdrawal forces are minimized by using generous tolerances and assuring integrity of the connection through utilization of opposed locking ramp members to resist connector and power cord separation forces. Exterior lock members on the second connector body engage a pair of first ramp members on the first connector body. A power cord strain relief fitting is held within an insert assembly which is insertable into an open end of the second connector body. Second ramp members on the insert assembly engage openings in the second connector body whereby axial forces on the strain relief fitting are transferred from the insert assembly to the second connector body, and then to the first connector body by means of the first ramp members.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to mateable electrical connector bodies 
interlockable for transfer of all connector and power cord separation 
forces to the structure of the connector bodies, and unlockable for 
electrical connection and disconnection with minimium insertion and 
withdrawal forces. 
2. Description of the Prior Art 
In joining a pair of connector bodies to inter-engage the internal 
electrical connector blades and contacts of the bodies it is important to 
insure that the blades and contacts are tightly engaged and are 
constrained from inadvertent separation, and that strains on the power 
cord are not transmitted to the electrical connections. This is 
accomplished by many connectors of the prior art by providing various 
forms of strain relief fittings and by providing a close tolerance fit 
between the blades and contacts and also between the connector bodies. 
However, an undesirably high insertion and withdrawal forces are required, 
in addition to the manufacturing problems associated with producing and 
assembling close tolerance parts. Further, such high forces often result 
in unseating of the strain relief fitting. 
One form of prior art connector reduces the necessary insertion and 
withdrawal forces by providing ramps on one of the connector bodies 
engageable by locking members on the other connector body. This 
arrangement works reasonably well, but there is no corresponding reduction 
in the insertion forces required to fit the usual power cord strain relief 
fitting into its connector body. 
In some prior art designs the strain relief fitting is made of resilient 
material which is pressed through an undersized opening in the connector 
body to seat it in position and, consequently, an equal withdrawal force 
will undesirably unseat the strain fitting from its connector body and 
damage the internal wiring connections. 
In other arrangements of the prior art the strain relief fitting is 
specially configured to fit through a complementally configured opening in 
the connector body, following which the strain relief fitting is turned or 
indexed to maintain it in position. What is needed, however, is an overall 
connector in which the various parts can be joined together or assembled 
with minimum forces, but which can be quickly and easily locked together 
to maintain the integrity of the connection or assembly. 
SUMMARY OF THE INVENTION 
According to the present invention, a pair of electrical connector bodies 
having internal, mutually engageable electrical connector blades and 
contacts are joinable and separable with minimum insertion and withdrawal 
forces. This is accomplished by providing generous tolerances between the 
interfitting parts, consistent with good electrical conducting 
relationship, and by providing positive locking through interengagement 
between locking members on one connector body and first ramp members on 
the other connector body. The locking members are easily pivotable to 
unlock the bodies when desired. 
The female connector body axially slidably accepts the assembled halves of 
an insert assembly having collar recesses adapted to close about the 
collar of a power cord strain relief fitting to securely hold the fitting 
in position within the insert assembly. 
The interfitting portions of the insert assembly and the associated 
connector body are characterized by generous tolerances so that assembly 
can be made with minimum insertion forces. The insert assembly includes 
oppositely located second ramp members which fit or snap into complemental 
ramp openings in the connector body to lock the insert assembly in 
position. 
The ramp surfaces of the first and second ramp members are oppositely 
sloped so that the vertical ramp surfaces transfer axial forces on the 
strain relief fitting from the insert assembly to the associated connector 
body by means of the second ramp members, and then to the other connector 
body by means of the first ramp members. 
Other objects and features of the invention will become apparent from 
consideration of the following description taken in connection with the 
accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to the drawings, there is illustrated an electrical connector 
10 according to the present invention, and comprising a male or first 
connector body 12 and a female or second connector body 14, the second 
connector body 14 being adapted to slidably receive an insert assembly 16 
within which is seated a strain relief fitting 18 molded or otherwise 
mounted upon a usual power cord 20 whose internal wires terminate in three 
electrical contacts (not shown) adapted to axially slidably receive three 
axially extending electrical connector blades 22 interiorly located and 
fixed within the first connector body 12. 
The first connector body 12 is shown in the form of an appliance inlet for 
a typewriter or the like, the blades 22 being connected to the typewriter 
motor by any suitable electrical cord or conduit (not shown). 
The connector body 12 includes a closed end hollow portion 24 of generally 
rectangular transverse cross-section except for beveled or sloping upper 
corners. The body 12 further includes a shroud or sleeve 26 integral with 
the portion 24 and also of generally rectangular cross-section, although 
somewhat larger in height and width. The sleeve 26 is characterized by 
horizontal walls 28 and vertical walls 30 in which are formed a pair of 
elongated, axially extending and oppositely disposed ways of slots 32. In 
addition, the sleeve 26 includes laterally extending flanges 34 having 
fastener openings for securing the body 12 to fixed structure such as a 
wall 36 associated with the typewriter. 
The outer surfaces of the horizontal walls 28 of the sleeve 26 include a 
pair of oppositely disposed first ramp members 38 which are each 
characterized by a vertical wall 40 and a sloping ramp 42, as best seen in 
FIG. 2. 
The second connector body 14 includes a closed end plug portion 44 adapted 
to axially slidably fit within the hollow interior of the portion 24 of 
the other connector body 12, the upper corners of the generally 
rectangular plug portion 44 being sloped to complementally fit within the 
sloped upper corners of the portion 24. The closed end of the plug portion 
44 includes three openings, (not shown) through which the blades 22 can 
project when the plug portion 44 is within the portion 24 in the assembled 
or insert position of the bodies 12 and 14. 
Integral with the plug portion 44 is a hollow housing portion 46 having an 
open end for receiving the insert assembly 16, as will be seen. 
The housing portion 46 is of generally rectangular configuration in 
transverse cross-section, and its exterior dimensions are larger than the 
corresponding dimensions of the plug portion 44, thereby defining a 
perimetrical abutment wall 48 which is spaced slightly away from the base 
wall 50 of the first connector body sleeve 26 in the insert position of 
the bodies 12 and 14. 
The opposite sides of the housing portions 46 include a pair of elongated, 
axially extending projections or guides 52 which slidably fit and seat 
within the slots 32 of the first connector body 12 in the insert position 
of the bodies, serving to axially align the bodies and particularly to 
prevent drooping of the connector body 14 relative to the connector body 
12 under the weight of the power cord 20. 
The housing portion 46 includes exteriorly located upper and lower lock 
members 54 which are integrally molded as a part of the main body of the 
housing portion 46. Such lock members 54 are well known in the prior art, 
the particular lock members 54 of the present invention each being 
characterized by a generally rectangular front projection 56 having a 
rectangular central ramp opening 58 and a downwardly and inwardly sloped 
leading edge 60. Each lock member 54 also includes an oppositely 
extending, generally rectangular rear projection 62 which can be depressed 
to pivot the lock member 54 about a vertical leg 64 which integrally joins 
the lock member 54 to the housing portion 46. Such pivotal movement, as 
will be seen, raises the front projection 56 so that it will disengage the 
associated first ramp member 38. 
The connector body 14 is preferably made of nylon or similar material which 
can be molded to provide a vertical leg 64 adapted to be deformed to 
provide the desired pivotal movement of the lock member 54, while yet 
resisting cracking or other structural failure which repetitive pivoting 
would cause in many other materials. 
The insert assembly 16 which slidably axially fits within the open end of 
the housing portion 46 comprises an upper half 66 and a lower half 68 
which are preferably moled in one piece, being joined by a hinge section 
70, as best seen in FIG. 3. The lower half 68 is longer than the upper 
half 66 to provide usual cavities or recesses 72, 74 and 76 for seating 
and retention of the usual electrical connectors (not shown) forming the 
terminations of the wires in the power cord 20. 
The insert upper half 66 includes a pair of end walls 78 and 80 which are 
spaced apart to define a collar recess 81, the other half 68 also 
including end walls 82 and 84 which are spaced apart to define a collar 
recess 86. All of these end walls include semi-cylindrical openings so 
that, upon movement of the upper half 66 onto the lower half 68 by bending 
at the hinge section 70, a generally rectangular collar recess is formed 
having a circular opening therethrough. The strain relief fitting 18 fits 
through the circular opening, and a collar 88 of the fitting 18 fits 
within the collar recess formed by the recesses 81 and 86. The collar 18 
is made of relatively rigid or non-elastomeric material so that it is 
incapable of being unseated from the collar recess by pulling upon the 
power cord 20. 
Pins 90 on the end wall 78 fit within openings 92 in the end wall 82 to 
properly locate the insert halves 66 and 68 for assembly. 
With the foregoing arrangement, any axial pull or power cord separation 
forces imposed on the collar 88 are transferred to the adjacent structure 
of the insert assembly 16 and not to the electrical wiring and 
blade/contact connections. 
A pair of second ramp members 94, as best seen in FIG. 2, are integrally 
molded on the outer, opposite surfaces of the halves 66 and 68. Each ramp 
member 94 includes a surface which slopes oppositely of the slope of the 
first ramp members 38. Upon insertion of the insert assembly 16 into the 
open end of the second connector body 14, the ramps 94 upwardly deflect 
the walls of the housing portion 46 until the ramps 94 come into alignment 
with a pair of ramp openings 96 in the upper and lower walls of the 
housing portion 46, at which point the outwardly deflected walls resume 
their unstressed positions and capture the ramp members 94 within the ramp 
openings 96 and prevent withdrawal of the insert assembly 16. The only way 
the insert assembly 16 can be removed is by application of sufficient 
pressure upon the ramp members 94 to move them inwardly and out of the 
ramp openings 96. 
From the foregoing it will be apparent that any forces developed by pulling 
upon the cord 20 will be transmitted to the insert assembly 16, and from 
the insert assembly 16 to the connector body 14 by means of the second 
ramp members 94, and then to the connector body 12 by means of the first 
ramp members 38. The integrity of the electrical connection between the 
bodies 12 and 14 is thus maintained, despite relatively high connector and 
power cord separation forces, since all of such forces are borne by the 
wall 36 to which the connector body 12 is secured. 
Various modifications and changes may be made with regard to the foregoing 
detailed description without departing from the spirit of the invention.