ASSEMBLAGE D'ANGLE A TROIS ELEMENTS

CORNER CONNECTION FOR THREE FRAME MEMBERS

Abrégé anglais

Abstract of the Disclosure
Connecting means are disclosed for establishing an
electrical connection between sheet metal elements that are to
be connected together by screw means. The elements are per-
forated for the passage of the screw means and the perforations
are formed in pressed-out conical areas in the sheet metal ele-
ments. The conical elements are adapted to mate when secured
together, with the outer surface of one conical area mating with
the inner surface of the other conical area. One of the outer
and inner surfaces is formed with narrow integral radial ribs
for engaging the other of the outer and inner surfaces to make
electrical connection when the screw is tightened.

Revendications

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. Connecting means for establishing an electrical
connection between sheet metal elements that are to be connected
together by screw means, said elements being perforated for
the passage of the screw means, the perforations being formed
in pressed-out conical areas in the sheet metal elements, said
conical elements being adapted to mate when secured together,
with the outer surface of one conical area mating with the
inner surface of the other conical area, one of the outer and
inner surfaces being formed with narrow integral radial ribs
for engaging the other of the outer and inner surfaces to
make said electrical connection when the screw is tightened.
2. The connecting means defined in claim 1 wherein both
the outer and inner surfaces are formed with said ribs.
3. The connecting means defined in claim 1 or 2 wherein
the cone angles of said conical areas differ whereby said areas
are elastically deformed into contact when the screw means are
tightened.
4. The connecting means defined in claim 1 or 2 wherein
the screw means comprise a nut and bolt.

Description

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This invention relates to an electrical connec~ion
especially for switchgear cabinets.
According to the present invention there is provided
connecting means for establishing an electrical connection -
between sheet metal elements that are to be connected together
by screw means, said elements being perforated for the passage
of the screw means, the perforations being formed in pressed-
out conical areas in the sheet metal elements, said conical
elements being adapted to mate when sacured together, with the
outer surface of one conical area mating with the inner surface
of the other conical area, one of the outer and inner surfaces
being formed with narrow integral radial ribs for engaging the
other of the outer and inner surfaces to make said electrical
connection when the screw is tightened.
Both the outer and inner surfaces may advantageously
be formed with said ribs.
The cone angles of said conical areas may differ
whereby said areas are elastically deformed into contact when
the screw means are tightened.
The screw means preferably comprise a nut and bolt.
The present invention may be carried into practice
in a number of ways, but some specific embodiments will now be
described, by way o example only, with reference to the
accompanying drawings, in which:
Figure 1 is a sectional view showing one embodiment
o a connection between two frame members;
Figure 2 i5 a sectional view showing another embodi-
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ment o~ a connection between ~rame members.
The connection as shown in Figures 1 and 2 may comprise
a countersunk screw 5 and a nut 6.
The bolted parts 1 and ~ have interfitting funnel-
shaped pressed-out regions 7, 8 (Figure 1) or 9, 10 (Figure 2~
so that each pair of interfitting pressed-out re~ions provides
a so-called countersink ~or penetration of the head o~ the
countersunk screw 5. At least one of the pressed~out regions
7, 8 or 9, 10 may have a cone angle which dif~ers from the cone
angle o~ the head o the countersunk screw 5, i.e., which
inclines away from the head of the screw 51 and should also be
elastically deformable on tightening o~ the screw connection 5,
6. The head of the countersunk screw 5 is, in the arrangements
shown in Figures 1 and 2, disposed in the open cone o one
pressed-out region 8 or 9. The nut 6 bears against the other
pressed-out region 7 or 10.
In order to obtain a smooth outer surface of ~he
connection it is arranged that in each case the pressed-out
regions 8, 9 of the frame members 1 and 4 engage in the respect-
ive pressed-out regions 7 or 10.
The particular advantage of the described arrangement
of the bosses 7, 8 and 9, 10 consists in that the countersunk
screw 5 is secured in simple manner against unintentional
loosening. The safeguard is achieved by the act that when the
parts 1 and 4 are bolted to~ether, the coun~ersunk screw 5 is
constantly under tension from the pressed-out region which is
elastically deformed. The elastically de~ormed pressed out
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region th~refore acts as a cup spring and compensates for any
elongation o~ the countersunk screw 5. The cone angles of the
pressed-out regions 7, 8, 9, 10 may both incline away from the
head of the co~mtersunk screw (Figure 1). It is~ however,
possible that only the cone angle of one pressed-out region,
in Figure 2 the cone angle of the pressed-out region 10, inclines
away from the h~ad of the countersunk screw 5.
The cone angles inclining away from the head of the
countersunk screw 5 may be smaller or greater than the cone
angle o~ the head of the countersunk screw 5.
In order that the cup spring action of the pressed-
out regions 7, 8 or 10 inclining away from the cone angle of
the head of the countersunk screw 5 cannot be released by
excessive extension of the countersunk screw 5, the countersunk
screw 5 is preferably made of a high-tensile steel with low
expansion.
At least one of the facing surfaces of the pressed-
out regions 7, 8; 9, 10 i5 provided with narrow radially-
extending ribs. In Figure 1 the region 7 is provided internally
with ribs 7a. In Figure 2 the region 10 has ribs lOa. It may
also be expedient to provide each pressed-out region 7, 8; 9,
10 with radially-extending ribs both internally and externally.
The ribs may, for example, be ~ormed by pressing the regions 7,
B; 9, 10 between a plunger which can be either smooth or pro-
vided with radially-extending ribs and a matrix provided with
radially-extending ribs. A metallic contact of the interfitting
regions 7, 8; 9, 10 is created when they are clamped together
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even when they are initially covered with an electrically
insulating layer, for example a coat o~ paint or a layer of
plastics material applied by a powder coating process. The
narrow ribs 7a, lOa of the regions 7, 10 exert a high contact
pressure on the opposite region 8, 9 when clamped together
and thus penetrate the electrically insulating layer until
metallic contact occurs. This metallic contact is therefore
achieved on assembly without additional work or additional
parts.
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