U.S. patent number 3,740,694 [Application Number 05/245,580] was granted by the patent office on 1973-06-19 for shield for electrical plug.
Invention is credited to Donald M. Fisher.
United States Patent |
3,740,694 |
Fisher |
June 19, 1973 |
SHIELD FOR ELECTRICAL PLUG
Abstract
Disclosed is a safety shield for an electrical connector plug
formed of a flexible resilient material having a base wall from
which the plug prongs extend and including flaps which extend along
a substantial portion of the length of the prongs. The flaps extend
at an obtuse angle to the plane of the base wall and are provided
with a curved lip which engages the receptacle as the plug is
inserted and pushed into the receptacle and insures that the flaps
are driven outwardly away from the prongs as the plug moves into
the receptacle.
Inventors: |
Fisher; Donald M. (Clayton,
IN) |
Family
ID: |
22927249 |
Appl.
No.: |
05/245,580 |
Filed: |
April 19, 1972 |
Current U.S.
Class: |
439/140; 439/138;
439/915 |
Current CPC
Class: |
H01R
13/453 (20130101); Y10S 439/915 (20130101) |
Current International
Class: |
H01R
13/44 (20060101); H01R 13/453 (20060101); H01r
013/44 (); H01r 013/52 () |
Field of
Search: |
;339/36,42,40,45R,75R,75P,59-63,94R,94A,94M,11P,176R,176P,195R,196R |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Champion; Marvin A.
Assistant Examiner: Lewis; Terrell P.
Claims
I claim:
1. An electrical safety plug adapted to plug into an electrical
outlet, said plug comprising a body portion having a planar face,
electrical prongs extending from said face of the plug body and
adapted to enter the registering apertures of an electrical outlet,
a sheath for said prongs formed by flexible resilient and
electrically insulating flaps extending from said plug body surface
along a substantial portion of the length of said prongs, two
opposite ones of said flaps having a width spanning the distance
between the prongs, two further opposite ones of said flaps having
a width at least equal to the width of said prongs, whereby the
ends of said flaps move outwardly to expose said prongs as the plug
is inserted in the outlet without subjecting said flaps to
appreciable compressive stress.
2. An electrical safety plug as claimed in claim 1 in which said
flaps have marginal end portions formed to curve outwardly to
provide receptacle engaging surfaces assuring outward movement of
the flaps as said prongs enter the receptacle apertures and
preventing jamming of the flaps between the plug body and the
receptacle.
3. An electrical safety plug as claimed in claim 1 in which the
inner facing side surfaces of said prongs are provided intermediate
their lengths with detent abutments extending slightly above the
prong surface and adapted to cooperate with the receptacle to
retain the plug in prong-inserted relation with the receptacle.
4. An insulating sheath for the prongs of an electrical plug of the
type adapted to be inserted in a receptacle, said sheath being
formed of a flexible resilient insulating material and having a
base wall from which a plurality of integral flaps extend at an
obtuse angle, said base wall of the sheath having apertures adapted
to receive the prongs of an electrical plug, said sheath being thus
adapted to be accommodated on the prongs of an electrical plug with
the sheath base wall contiguous with the adjacent surface of the
plug and said flaps extending for a substantial portion of the
length of the plug prongs, said flaps being moved outwardly away
from the prongs when the plug is inserted in the receptacle.
5. An insulating sheath as claimed in claim 4 in which said flaps
have marginal end portions formed to curve outwardly to provide
receptacle engaging surfaces assuring outward movement of the flaps
as the plug is fitted to the receptacle.
6. An insulating sheath as claimed in claim 4 in which said base
wall of the sheath is rectangular in configuration and an integral
flap extends from each of the four side margins of the base wall.
Description
BACKGROUND OF THE INVENTION
Various types of safety plugs or electrical connectors are well
known in the prior art. One primary objective of these prior art
structures is to cover or shield the prongs of the male component
of the separable connector while the plug is being inserted or
removed from the female component or receptacle. These structures
additionally provide shielding of the plug prongs when the plug,
though with the plug prongs still making electrical contact with
the receptacle terminals and at line voltage, is partially
separated from the receptacle. Such a condition, since domestic
electrical sockets or receptacles are often at baseboard level, is
a particular hazard for small children.
In general, two types of plug prong shielding devices are known in
the prior art. One type utilizes a rigid, spring-loaded shield
which advances and retreats over the plug prongs as the plug is
removed and inserted from the receptacle. An example of this
general structure is disclosed in U.S. Pat. No. 3,575,684. The
other type utilizes a flexible, resilient sleeve which is deformed
and flattened between the plug and receptacle when the plug is
inserted into the receptacle. This type of flexible shield is
disclosed in U.S. Pat. No. 3,147,055.
The safety plug shield of the present invention is an improved
version of the latter type mentioned above, and can be embodied in
a separate flapped sheath to be fitted on the prongs of a
conventional electrical plug. It has the advantage over prior art
structures in that the prong shielding portion is not placed in
extreme compressive stress when the plug is seated against the
receptacle. Instead of being compressed between the plug and
receptacle as the plug is inserted in the receptacle, the flaps of
the shield embodying the present invention are forced outwardly
away from the plug prongs. They spring back to prong-shielding
position as the plug is withdrawn from the receptacle. Since the
shield is not subjected to extreme compressive stress, as is
typical of prior art structures, it has a prolonged service
life.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of an electrical plug shield embodying
the present invention.
FIG. 2 is a top view of a conventional electrical plug with the
shield of FIG. 1 installed on it, the shield being shown in
section.
FIG. 3 is a side view of the structure shown in FIG. 2.
FIG. 4 is a perspective view of a modified form of the
invention.
FIG. 5 is a top plan view, partially in section, of the structure
shown in FIG. 4.
FIG. 6 is a front view of a conventional electrical receptacle.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Indicated generally at 10 in FIG. 1 is the insulating sheath
embodiment of the invention, adapted for placement on a
conventional electrical plug (indicated at 11 in FIG. 2). The
sheath is preferably formed of a resilient, flexible, but tough,
material such as ethylene vinyl acetate and has a generally
rectangular cup-shape. The base wall 12 of the sheath has extending
from it integral side flaps 13 and 14 and end flaps 16 and 17. The
flaps extend outwardly somewhat, that is, at an obtuse angle, with
respect to the plane of the base wall 12, and, at their outer
margins, the flaps are curved outwardly as indicated at 13a, 14a,
16a and 17a.
The base wall 12 of the sheath is provided with apertures 18 and 19
(FIG. 1) adapted to accommodate the prongs 11a of the electrical
plug. As may be seen in FIGS. 2 and 3, when the sheath is in place
on the plug the base wall 12 is contiguous with the adjacent flat
surface of the plug 10 and the flaps extend along a substantial
portion of the length of the prongs 11a.
In operation, with the sheath 10 installed on the plug 11, as the
plug prongs are inserted into a conventional electrical receptacle
(indicated at 21 in FIG. 6), the extending flaps will engage the
face 21a of the receptacle. As the plug is moved into fully
inserted position, the flaps will be forced outwardly, their angle
of extension from the sheath base and their curved margins assuring
that the flaps will be moved outwardly and will not jam between the
receptacle face and the plug. The flaps are moved to this outwardly
extended position without undergoing extreme stress, and they
spring back to sheathing position with respect to the prongs as the
plug is removed from the receptacle. If the plug is, inadvertently
only partially removed from the receptacle, the flaps cover the
portion of the prongs outside the receptacle. Since the flaps are
not greatly stressed, the service life of the sheath is
prolonged.
Referring to FIGS. 4 and 5, a modified form of the structure is
shown wherein the sheath flaps extend from and are molded
integrally with electrical plug. The plug, itself, further differs
from the conventional type type shown in FIGS. 2 and 3 in that the
prongs 26 of the plug 27 are provided with abutments 28. The
abutments are preferably formed by striking them from the metal
forming the prongs, and they extend above the prong surface and are
aligned with each other. The purpose of these abutments is to
provide detenting retainers for holding the plug firmly seated in
the electrical receptacle. They are positioned to detent on, or
snap behind the front face 21a of a receptacle 21 (FIG. 6) and are
a convenient, economical means for providing a detent position of
the plug when inserted into the receptacle.
The plug 27 (FIG. 4) is molded of a suitable material, such as
polyvinyl chloride, and flaps 31, 32, 33 and 34 are molded
integrally with the body of the plug and extend at an obtuse angle
with respect to the flat face 27a of the plug. They are provided
with outwardly curved marginal areas to assure, as with the
structure of FIGS. 1-3, that the flaps are moved outwardly as the
plug is inserted into a receptacle.
* * * * *