U.S. patent number 3,627,900 [Application Number 04/883,121] was granted by the patent office on 1971-12-14 for ground clamp.
This patent grant is currently assigned to Cornell-Dubilier Electric Corporation. Invention is credited to William M. Robinson.
United States Patent |
3,627,900 |
Robinson |
December 14, 1971 |
GROUND CLAMP
Abstract
Connection is made to a metal container having a bead, by means
of a resilient clamp that embraces the bead, and
surface-penetrating tines, and a terminal part to which a wire
connection may be made.
Inventors: |
Robinson; William M. (New
Bedford, MA) |
Assignee: |
Cornell-Dubilier Electric
Corporation (Newark, NJ)
|
Family
ID: |
25382032 |
Appl.
No.: |
04/883,121 |
Filed: |
December 8, 1969 |
Current U.S.
Class: |
174/11R; 174/51;
439/387; 439/92; 439/95 |
Current CPC
Class: |
H01R
4/4809 (20130101) |
Current International
Class: |
H01R
4/48 (20060101); H05k 005/02 () |
Field of
Search: |
;174/51,40.1
;339/14R,95R,95A,95D ;317/256,242 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Clay; Darrell L.
Claims
I claim:
1. In combination a metal container having an electrical ground
clamp, said container including a sidewall and a projecting bead
extending along an edge of the sidewall and having an outer portion
disposed against said sidewall as a projection thereon, said ground
clamp comprising a resilient sheet-metal member having a body part
disposed against a side of said container adjacent a bead thereof,
a barb portion extending integrally from said body part around and
closely adjacent to an end portion of the bead and extending as a
reverse bend to at least one terminating tine in firm
surface-penetrating engagement with an inside lateral surface of
the bead at a point approximately aligned with an edge of the outer
portion of the bead, said body portion also having an edge portion
engaging said sidewall of the container at a point substantially
spaced from said bead, and an electrical terminal part projecting
integrally from said body portion and projecting from the container
to an accessible space whereby the position of the ground clamp on
the container is relatively immune to stresses imposed externally
on said electrical terminal.
2. The combination of a metal container and an electrical ground
clamp in accordance with claim 1, further including a pair of
lanced abutments disposed opposite said sidewall and substantially
in abutment with the edge of said outer portion of the bead, said
abutments being spaced relatively far apart.
3. The combination of a metal container and an electrical ground
clamp in accordance with claim 2, wherein said bead is tightly
received between the part of said body portion that extends across
the end of said bead and said lanced abutments.
4. The combination of a metal container and an electrical ground
clamp in accordance with claim 2, wherein at least one tine of said
barb portion is disposed opposite the space delimited by said
lanced abutments.
Description
The present invention relates to an electrical ground clamp,
forming an electrical connector to the container of an electrical
component, for making a ground connection thereto.
An object of the present invention resides in providing a new form
of ground clamp wherein a paint- and surface-penetrating barb is
forced against one side of a bead of a sheet-metal container and
wherein the ground clamp engages the lateral surface of the
container and abuts widely spaced edge portions of a bead of the
container, for effectively resisting stresses applied to a
projecting electrical terminal of the ground clamp, for maintaining
a stable contact of the barb to the container.
The nature of the invention and its various objects and features of
novelty, and their advantages, will be best appreciated from the
following description in detail of an illustrative embodiment of
the invention which is shown in the accompanying drawings. In the
drawings:
FIG. 1 is a side elevation of an electrical capacitor bearing a
ground clamp, as an illustrative embodiment of the invention;
FIG. 2 is an enlarged view of the illustrative ground clamp and a
fragment of the container as viewed from the right of FIG. 1;
FIG. 3 is an enlarged side elevation of the ground clamp, including
a fragmentary portion of the container in cross section as viewed
at the plane 3-3 of FIG. 2; and
FIG. 4 is a cross-sectional view of the clamp of FIGS. 2 and 3 as
viewed from the section line 4-4 of FIG. 3 including a portion of
the container.
In the drawings, a capacitor is shown having a sheet-metal
enclosure comprising a drawn "can" or body 10 and a cover 12 having
various capacitor terminals 14 thereon. Body 10 and cover 12 are
joined to each other by a bead 16 that is sealed hermetically,
optionally with solder, resistance-welding, a gasket or the like.
In a common form of container, the horizontal cross section is
generally oval so as to have semicircular portions (one of which is
shown in FIG. 1) and a pair of flat sidewalls 10a perpendicular to
the plane of FIG. 1.
A novel embodiment of a highly successful clamp 20 that provides a
stable and dependable grounding connection to the metal enclosure
appears in FIG. 1 and, drawn to larger scale, in FIGS. 2, 3 and
4.
Ground clamp 20 includes a body part 22. A barb 24 extends
integrally from body part 22 and includes two tines 26 that have
sharp and hard edges for penetrating into cover 12 and through any
paint and phosphatizing or other protective surface treatment on
such sheet metal containers. Ground clamp 20 is formed of hard
resilient sheet-metal. Tines 26 have adequate pressure so that,
being hard and sharp, they penetrate into the metal of the
enclosure. The space between tines 26 and body part 22 is
originally somewhat smaller than the thickness of the bead 16 to
which the ground clamp is applied so that after the ground clamp is
applied the tines bear against the bead with sustained resilient
pressure.
The reverse-bent barb portion 24 of the ground clamp extends
integrally from body part 22 as already indicated, extending around
the upper edge of bead 16; but (see FIG. 2) barb portion 24 takes
up only about half of the width of body portion 22. The other half
of body portion 22 is extended to provide an electrical terminal
part 28 projecting upward from the container to a position of
clearance to be accessible for making terminal connection thereto.
Terminal part 28 can be used either for a spring-clip connector of
approved design or for a soldered connection or in any other
manner. Because of the fact that terminal part 28 projects from the
enclosure, it is subjected to stress both when a connection is
being made to it, and accidentally after the capacitor has been
installed. The danger is that the ground clamp might shift around
and even become dislodged entirely, leading to possible
deterioration of the electrical connection made by the barb part of
the ground clamp. Once tines 26 have assumed their installed
contact positions, those contact portions should be stable and
should remain in position.
A pair of tongues 30 are lanced or struck up out of the body
portion 22 at widely spaced points, at the edges as shown, and in
position to abut the lower edge of bead 16. This abutment is along
a line almost directly opposite to the tines 26. Abutments 30 are
separated laterally far from each other and for this reason they
provide a great deal of stability in case of a side-to-side force
that might be applied to projecting terminal 28, applied
right-to-left or left-to-right as viewed in FIG. 2. The fact that
the portion 24a of barb portion 24 that extends over the bead bears
against the bead when abutments 30 engage the edge of the bead,
means that virtually no rocking of the ground clamp can occur when
force is applied to terminal 28 in a right-to-left direction or
left-to-right as viewed in FIG. 2. The lower edge portion 32 of the
ground clamp is curled inward somewhat, and provides a bearing
point that is located at a substantial distance from bead 16. This
avoids any leverage or force-multiplication when a deflecting force
is applied to terminal part 28, from left-to-right as viewed in
FIG. 3. In case of right-to-left force applied to terminal portion
28 (FIG. 3) the tines tend to remain in their established positions
against bead 16. The gripping force of the reverse-bent tine 24 and
body 22 is great enough to prevent abutments 30 from shifting out
of locking engagement with the edges of bead 16.
In its manufactured condition, before being applied to the
container, the space between tines 26 and body portion 22 of the
ground clamp 28 is substantially less than the thickness of bead 16
on which the ground clamp is to be used. The ground clamp is driven
downward into the position shown. Tines 26 create shallow grooves
in the surface of bead 16 and thus are effective to make good
electrical contact to the metal of the container. The distance
between the abutment edges of lanced abutments 30 and the part 24a
of the barb 24 that loops over the upper edge of bead 16 is such
that resilient abutments 30 snap into place under the edge of bead
16 when portion 24a is driven against the upper edge of the bead.
Bead 16 is tightly received between abutments 30 and portion 24a of
the reverse-bent barb. The whole ground clamp is formed of hard,
prominently resilient stock as has already been indicated, and
advantageously it is of noncorrosive materials. Beryllium-copper is
one suitable material. Stainless steel is also suitable and in some
cases it may be found practical to use spring steel that has been
given stable surface-oxidizing treatment. In any case the gauge of
the sheet-metal used in making the ground clamp is chosen in
relation to the dimensions of the clamp and the required resiliency
so that tines 26 are forced against bead 16 and penetrate through
the surface protection that normally covers the container including
bead 16. Once installed, ground clamp 20 is remarkably immune to
stresses that may be applied to terminal 28, both when connections
are being made to terminal 28 and in handling thereafter.
It is evident that the novel concepts in the illustrative
embodiment of the invention are subject to a latitude of change and
may be utilized in various applications and therefore the invention
should be construed broadly in accordance with its full spirit and
scope.
* * * * *