Expanded – threaded – driven – headed – tool-deformed – or locked-thr – Threaded fastener locked to a discreet structure – Nut – and means to engage substructure on its opposite faces...
Reexamination Certificate
2001-04-06
2003-04-08
Saether, Flemming (Department: 3679)
Expanded, threaded, driven, headed, tool-deformed, or locked-thr
Threaded fastener locked to a discreet structure
Nut, and means to engage substructure on its opposite faces...
C029S522100
Reexamination Certificate
active
06543979
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a clinch nut assembly and a method of producing a clinch nut, and more particularly to a clinch nut assembly, in which a clinch nut is previously fixed to a sheet metal, and a method of producing such a clinch nut.
BACKGROUND OF THE INVENTION
As a nut previously fixed to a sheet metal, Japanese Laid-open Patent Publication No.sho.60-252814 discloses a clinch nut. As shown in
FIG. 16
, the clinch nut
51
comprises, on a bottom end surface facing to a sheet metal, an internal cylindrical portion
52
with a screw hole
53
for punching the sheet metal in order to provide a bolt insertion hole in the sheet metal and an external cylindrical portion
54
. An annular groove
56
is formed coaxially with the screw hole
53
and between the internal cylindrical portion
52
and the external cylindrical portion
54
. The external cylindrical portion
54
is shorter than the internal cylindrical
20
portion
52
, and the inner peripheral surface
55
of the external cylindrical portion
54
is provided with an engaging part, which is of a reverse tapered shape extending from the bottom end surface, for interlocking with the periphery of the bolt insertion hole of the sheet metal.
As a nut having a similar construction to the aforementioned clinch nut
51
, Japanese Laid-open Patent Publication No. Hei 11-193808 discloses a pierce nut. As shown in
FIG. 17
, the pierce nut
61
comprises an internal cylindrical portion
62
, an external cylindrical portion
64
and an annular groove
66
formed between the internal cylindrical portion
62
and the external cylindrical portion
64
. The outer peripheral surface
63
of the internal cylindrical portion
62
is provided with an engaging part, which is of a reverse tapered shape extending toward the end facing to the sheet metal, for interlocking with the periphery of the bolt insertion hole. The external cylindrical portion
64
has an enlarged end surface abutting to the sheet metal.
However, since these clinch nut
51
and pierce nut
61
have a construction, in which the internal cylindrical portion
52
,
62
and the external cylindrical portion
54
,
64
are separatedby the annular groove
56
,
66
, the nut
51
,
61
tends to be enlarged in its profile toward the radial direction. As a result, when positioning a plurality of nuts
51
,
61
in an adjacent manner, the pitch interval of the respective adjacent nuts
51
,
61
becomes lager. Therefore, a problem will arise when fixing a plurality of nuts
51
,
61
to a smaller sheet metal such as a small-sized bracket or flange. Meanwhile, if the diameter of the clinch nut
51
and the pierce nut
61
is reduced, the contacting area of the end surface of the external cylindrical portion
54
,
64
, which abuts to the sheet metal, becomes smaller and hence the joint strength between the nut
51
,
61
and the sheet metal is restricted.
With the aforementioned drawbacks of the prior art in view, the present invention seeks to provide a clinch nut assembly, in which a clinch nut can be reduced its size while ensuring a sufficient contacting area with regard to the sheet metal, so that the nut can be firmly fixed to the sheet metal. The present invention also seeks to provide a method for readily producing a clinch nut adapted to use with the clinch nut assembly.
SUMMARY OF THE INVENTION
According to a first aspect of the invention, there is provided a clinch nut assembly comprising:
a sheet metal having a bolt insertion hole; and
a clinch nut to be fixed to said sheet metal, wherein said clinch nut is provided with a recess portion at one end facing to the sheet metal so as to receive a tubular projection formed around the bolt insertion hole, and wherein an engaging part is provided around a peripheral wall of said recess portion for interlocking with said tubular projection.
In such a clinch nut assembly, the tubular projection formed around the bolt insertion hole of the sheet metal is fitted into the recess portion provided at one end of the clinch nut, and the tubular projection is forcibly deformed so as to interlock with the engaging part around the peripheral wall of the recess portion. The clinch nut is thereby fixed to the sheet metal with the whole end surface of the clinch nut contacting with the sheet metal.
According to a second aspect of the invention, there is provided a clinch nut assembly comprising:
a sheet metal having a bolt insertion hole;
a clinch nut to be fixed to said sheet metal, the clinch nut including a recess portion at one end facing to the sheet metal so as to receive a tubular projection formed around the bolt insertion hole; and
a washer member fixed to said end of the clinch nut, an inner periphery of the washer member extending inwardly from a peripheral wall of said recess portion so as to form an engaging part for interlocking with said tubular projection.
In such a clinch nut assembly, the tubular projection formed around the bolt insertion hole of the sheet metal is fitted into the recess portion provided at one end of the clinch nut, and the tubular projection is forcibly deformed so as to interlock with the inner periphery of the washer member extending inwardly from the peripheral wall of the recess portion. The clinch nut is thereby fixed to the sheet metal with the whole end surface of the washer member contacting with the sheet metal.
The term “washer member” in this aspect of the invention indicates a plate-like member having a circular hole, which allows an insertion of the tubular projection of the sheet metal. Usually, the outer profile of the washer member is of circular shape, however, a polygonal shape, such as a square and a hexagon may be employed. The outside dimension of the washer member is decided in accordance with the outside dimension of the clinch nut so that the washer member has substantially the same or slightly greater dimension compared to the clinch nut. The diameter and the thickness of the hole of the washer member are decided in accordance with the thickness of the sheet metal. They may vary as long as retaining a function as an engaging part for interlocking with the tubular projection. The washer member is fixed to the end of the clinch nut by means of resistance welding and the like. For this reason, the washer member is preferably made of the same material as the clinch nut.
According to a third aspect of the invention, the aforementioned clinch nut assemblies further include a flange up washer with a reinforcement tubular projection, and said reinforcement tubular projection pressing an inner peripheral surface of the tubular projection of said sheet metal for interlocking said tubular projection with the clinch nut.
In such a clinch nut assemblies, since the reinforcement tubular projection of the flange up washer presses the inner peripheral surface of the tubular projection of the sheet metal, the clinch nut is more firmly fixed to the sheet metal.
The term “flange up washer” in this aspect of the invention indicates a washer, in which a reinforcement tubular projection is formed by way of fluing or flanging up at a center of its flange portion for insertion of a bolt. The reinforcement tubular projection of the flange up washer may be formed together with the tubular projection of the sheet metal with the flange portion attached to the sheet metal. Alternatively, the reinforcement tubular projection may be formed previously and individually. The flange up washer is preferably made of steel with high stiffness so as to firmly retain the interlocking state with regard to the tubular projection of the sheet metal. The flange portion of the flange up washer is not limited to a circular shape and may be polygonal, such as square and hexagonal. However, it is usually formed as a circular shape with substantially the same outside dimension of the clinch nut.
According to a fourth aspect of the invention, the clinch nut assembly according to the first aspect of the invention is characterized in that the sheet metal has a plurality of adjacent bolt insertio
Honda Giken Kogyo Kabushiki Kaisha
Saether Flemming
Schiffman Jori
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