Integral electrical shorting switch and connector assembly

An integral electrical shorting switch and connector assembly is disclosed having a pair of switch terminals each with a shorting end and an opposite contact end isolated from the environment. A conductive member for operatively shorting the switch terminals is mounted to a flexible, water-impervious boot surrounding and sealing the shorting end of the switch terminals, and a connector plug with contacts forms two interference fit seals at the contact end of the switch terminals.

BACKGROUND OF THE INVENTION 
This invention relates generally to electrical switches of the shorting or 
ignition killing type and, more particularly, to an improved electrical 
switch and connector assembly in which the switch terminals and 
connections thereto are isolated from the environment to insure reliable 
switch operation. 
Electrical switches of the type used for momentarily shorting a pair of 
conductors, such as those used in ignition to stop or kill an engine, are 
well known. Such switches are used for instance in lawn mowers or marine 
equipment and generally comprise two terminals, each having one end 
terminated by soldering or crimping to the respective ignition wires. The 
other ends of the switch terminals are spacially mounted a short distance 
apart so as to be selectively shorted by a movable conductor member when 
it is desired to turn off the associated engine. Under normal 
environmental conditions, such switches can be expected to operate 
reliabily. However, in high moisture conditions, such as encountered in 
marine equipment, water or other determintal substances often seep or 
otherwise find their way into the switch assembly and cause corrosion of 
the switch terminals. Since the terminals are generally enclosed, the 
corrosion may continue unnoticed, resulting in a condition where the 
switch terminals cannot be short circuited when desired by selective 
movement of the shorting member. Under severe situations, the corrosion 
may develop to such an extent that the switch terminals become 
intermittently or even permanently short circuited to cause unintended 
engine shut-off. In any event, the unreliable or inoperative switch must 
be replaced. 
In addition to the unreliable or inoperative switch condition, a build-up 
of corrosion at the connector end of the switch terminals causes a weak 
point at the termination between the ignition wire and the switch 
terminal. Undesired breaking of the termination at the weak point may 
result from a combination of factors, including corrosion and the lack of 
adequate support for the ignition wires. In addition, equipment vibration 
encountered under normal operating conditions which rapidly degrade an 
already weakened termination to the breaking point. 
SUMMARY OF THE INVENTION 
The present invention is, therefore, directed to a shorting switch and 
connection assembly which overcomes the problems of the prior art relating 
to the seepage of water or other detrimental substances into the shorting 
switch. Thus, corrosion at the shorting portion of the switch terminals 
and also at the opposite termination portions of the switch is greatly 
reduced. Means are provided for sealing both ends of the switch terminals 
to isolate them from the environment. In addition, means are provided in 
the connector portion of the present invention so as to minimize the 
factors which previously contributed to the deterioration and breaking of 
the ignition wires at the termination point. 
In accordance with one aspect of the present invention, an ignition kill 
switch is provided with a pair of elongated switch terminals mounted in a 
switch body, each terminal having a shorting portion end extending from 
the switch body so as to be surrounded and protected from the environment 
by an enclosure. The enclosure comprises a cavity formed in one end of the 
switch body covered by a conventional, flexible boot member, thereby 
isolating the shorting portion ends of the switch terminals in the cavity 
from the environment. A shorting conductor mounted in the boot projects 
into the cavity a short distance from the switch terminals so that 
deflection of the boot results in conductive engagement between the 
shorting conductor and the shorting portions of the switch terminals in 
the protected environment. 
The switch terminals each further include a contact end which projects into 
an elongated recess in the switch body. The elongated recess is also 
sealed from the environment by a connector plug having mating contacts. 
The connector plug provides a primary seal exterior of the switch body and 
a secondary seal on the recess interior to protect and isolate the switch 
terminal contact ends from the environment. A conductor strain relief and 
double seal is also provided on each plug for the ignition wires. Thus, 
the present invention substantially eliminates the formation of 
destructive corrosion encountered with prior art shorting switches by 
reliably enclosing the contact of the switch within a uniquely configured, 
connectorized sealing member.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring now to FIGS. 1 and 2 of the drawings, there is illustrated an 
ignition shorting or killing switch and connector assembly 10 including a 
switch portion 12 and a connector portion 14 at each end thereof. The 
switch portion 12 includes a generally cylindrical switch body 16 having a 
cavity 18 and an elongated recess 20 formed in opposite ends thereof. As 
can be seen from FIG. 1, the longitudinal recess 20 comprises an outer, 
cylindrical recess portion 22 at one extreme end of the switch body and an 
inner recess portion 24. 
The switch body 16 has two longitudinally or axially extending passageways 
such as 26 through which a respective elongated switch terminal 28 is 
inserted such as by press-fitting or well known ultrasonic welding means. 
Each of the switch terminals 28 includes a shorting portion 30 at one end 
which extends from the switch body in a hooked manner, reentrantly 
outwardly, shown best in FIG. 2, such that the very end thereof is 
press-fitted or ultrasonically inserted into the switch body. This hooked 
shape tends to stabilize the terminals during the switch operation. The 
other end of each switch terminal 28 comprises a male contact 32 which 
extends longitudinally into the switch body inner recess portion 24. 
The switch portion 12 further includes a generally cylindrical flange 34 
extending outwardly from and around the switch body to mate within a 
similarly shaped depression in the interior of a flexible boot member 36. 
As can be seen from FIG. 1, the boot 36 includes a sealing portion which 
is internally configured so as to sealingly engage the switch body. Thus, 
the shorting portions 30 of each of the switch terminals 28 is completely 
protected from moisture or other detrimental substances in the environment 
by being mounted in the cavity 18 such as to be completely surrounded by 
the switch body 16, the cavity wall 44 and the dome-like boot cap 42. 
A bell-shaped shorting member 46 is mounted by means of a rivet 48 or other 
suitable member so as to project within the cavity 18 and thereby be 
protected from the environment by the boot. One end of the rivet 48 
through conventional injection molding techniques may be captured within a 
protruding ridge 50 formed on the interior of the cap 42. The other end of 
rivet 48 passes through the shorting bell 46 and is enlarged in a known 
manner to lock the shorting bell in position. 
The bell-shaped or curved shorting member 46 is formed of a conducting 
material, such as brass or copper, and is mounted in the cap 42 so that 
its center is substantially axially aligned between the longitudinally 
extending portions of the switch terminals 28. The interior of the 
shorting member is concave and dimensioned so as to overlie the 
hook-shaped shorting portions 30 of the switch terminals. Circular ridges 
and a central ridge 52 are preferably formed on the outer surface of the 
cap 42 to improve the friction characteristics of the cap facilitate 
operation of the switch. 
In particular, shorting of the switch terminals 28 is accomplished by 
depressing the cap 42 and exerting an inward force sufficient to flex the 
cap 42 as shown in FIG. 2. The cap is momentarily depressed until the 
inner surfaces of the shorting bell 46 conductively engage each of the 
shorting portions 30. At that point, the associated engine stops running 
and the operator can release the pressure from cap 42 so that it flexes 
back to the non-shorting position shown in FIG. 1. It may be particularly 
noted that whereas the cap 42 flexes along a movable portion 54, the seals 
38 and 40 are still maintained between the boot 36 and the switch body 16. 
The boot 36 is formed of a water-impervious, flexible material and can be 
conveniently formed of a flexible elastomeric material. The switch body 16 
is preferably formed of dielectric thermoplastic. 
The switch portion 12 may be conveniently mounted to a panel (shown in 
phantom lines), and, in preferred form, the front edge 56 of the boot may 
be beveled so as to fit within a similarly beveled or counter-sunk panel 
portion. The switch body 16 in this case further includes an externally 
threaded portion 58 such that after the switch portion 12 is inserted 
through a beveled panel aperture, with the beveled edge 56 of the boot 
nested in the panel, the switch can be mounted by threading a nut (shown 
in phantom lines) onto the threaded portion 58 to urge the beveled edge 56 
in snug fitting and sealing engagement with the panel. It will be further 
appreciated that the boot 36 is captured between the panel on which the 
switch is mounted and flange 34, thereby positively clamping and sealing 
the boot with the switch body. 
The connector portion 14 of the switch 10 includes a generally cylindrical 
connector plug body 60 having two longitudinally extending passageways 62 
which receive respective elongated socket contacts 64 having tubular ends 
for receiving respective male contact ends 32 of the switch terminals. 
Each socket contact 64 may be of the hooded type having an outer sleeve 
with inner tines such that the tines are forceably spread apart so as to 
conductively engage the male contact 32. At the rear end of each of the 
contacts 64, an insulated conductor 66 is terminated by conventional 
soldering, crimping or insulation-piercing techniques. In this instance, 
the conductors 66 comprise the respective ignition wires coupled to an 
associated engine such that insertion of the connector portion 14 into the 
switch portion 12 electrically engages the conductors 66 with the 
respective switch terminals 28. 
The connector plug body 60 includes a generally cylindrical skirt portion 
68, having an inner protuberance or ridge 70 at its distal end with an 
inner diameter slightly less than the outer diameter of the recess wall 72 
such that the skirt 68 may be interference-fit onto the switch body 
thereby providing mounting retention of the connector portion with the 
switch portion. This interference-fit between skirt 68 and the external 
surface of outer recess wall 62 also provides a primary seal to prevent 
moisture or other undesirable substances from finding their way into the 
outer recess 22 and inner recess 24 in the interior of the switch body. 
A generally cylindrical portion 74 of plug body 60 is provided with a 
series of ridges 76, dimensioned so as to provide an interference-fit with 
the inner surface of recess wall 72. This provides a series of secondary 
mating seals between the connector plug body and the switch body to 
further prevent undesirable substances from eventually entering into the 
switch body and inner recess 24. Thus, the contact portions 32 of the 
switch terminals extending in switch body recess 20 are protected from the 
environment by the switch body recess walls and by the surrounding 
connector plug body with the primary seal 70 on the exterior of the recess 
and the sealing ridges 76 along the inside portion of the recess. 
Means are also provided for pre-aligning the connector portion and the 
switch portion such that the primary and secondary connector seals do not 
engage the switch body until axial alignment of the socket contacts 64 and 
the switch terminal contact ends 32 has occurred. With reference to FIG. 
6, the switch body recess 24 includes an inner wall surface 78 which is 
shaped so as to match the similarly shaped front portion 80 of the 
connector plug body 60. Thus, as the plug front extension 80 meets the 
inner recess 24, it must be properly oriented in order to obtain the 
alignment shown in FIG. 6. In addition, the length of the front portion 80 
extending from the front ridge 76 to the leading edge 82 is preferably 
equal to or slightly greater than the longitudinal dimension of outer 
recess 22, i.e., the length of the switch body between its outer edge 84 
and the step 86 at the beginning of inner recess 24. This dimensioning 
enables the front portion 80 of the connector to be readily oriented with 
inner recess 24 thus aligning the contacts, without having either the 
interference of ridges 76 or the protuberance 70 sealing onto the switch 
body. Once the proper alignment has been obtained, the socket contacts 64 
may be mated with the contact ends 32 of the switch terminals by pushing 
the plug body axially into the switch portion, thereby forming the firm 
interference-fit previously described for both the primary and secondary 
mating seals both inside and outside of the longitudinal switch body 
recess 20. 
The rear end of the connector plug body 60 further includes risers 88 and 
90 extending inwardly from the passageways 62. The risers 88 provide a 
support or strain relief for the conductors 66 and an individual seal for 
each conductor, while risers 90 provide contact retention to prevent 
rearward axial displacement of the contact. 
The connector plug body 60 is preferably formed of a flexible elastomeric 
material. Insertion of the socket contacts 64 into the passageways formed 
in plug body 60, may be provided with an appropriate insertion tool, such 
as that disclosed in copending application, U.S. Ser. No. 722,674, 
assigned to the same assignee as the present application. 
It will be appreciated by those skilled in the art that the construction of 
the present invention provides a reliable and quick-release, connectorized 
switch assembly. The possibility of failure due to corrossion is greatly 
reduced, if not entirely eliminated. The termination of the conductor 
leads to the switch terminals is also enhanced due to the improved 
mechanical or structural support given to the leads. For example, 
vibration and slight physical distortion of the connector plug should not 
impair the quality of the connection. 
Utilizing the principles of the invention, one may, if desired, reverse the 
male-female contacts described herein. Thus, female socket contacts rather 
than male contacts can be provided for contact portion 32 at the inner 
recess 24. The plug body would then include projecting male contacts 
rather than the socket contacts 64. 
Of course, it should be understood that other changes and modifications to 
the preferred embodiments described herein will be apparent to those 
skilled in the art. Such changes and modifications can be made without 
departing from the spirit and scope of the present invention and without 
diminishing its attendant advantages. It is, therefore, intended that such 
changes and modifications be covered by the following claims.