Wedge anchor

Details Wedge anchor Wedge anchor

2001-03-19

2003-02-25

Wilson, Neill (Department: 3679)

Expanded, threaded, driven, headed, tool-deformed, or locked-thr

Having separate expander means

Including sleeve and distinct tapered expander

C411S051000, C411S055000, C411S060200

Reexamination Certificate

active

06524046

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a wedge anchor, more particularly to one that can be driven quickly into a blind hole and that can ensure a stable securing effect.
2. Description of the Related Art
Referring to
FIG. 1
, a conventional wedge anchor
1
is shown to include a shank
11
, a tubular expansion sleeve
12
, a washer
13
, and a nut fastener
14
. The shank
11
has a threaded section
111
, a neck section
112
extending forwardly and coaxially from one end of the threaded section
111
, and having a diameter slightly smaller than that of the threaded section
111
, and an expander section
113
extending fowardly and coaxially from one end of the neck section
112
. The expander section
113
has a frusto conical configuration with a cross-section that gradually decreases along an axis of the shank
11
in a direction toward the threaded section
111
. The expander section
113
further has a surface that forms an angle of less than 8° with respect to the axis of the shank
11
. The expansion sleeve
12
is shorter than the shank
11
, is sleeved on the neck section
112
, and is formed from two interconnected retaining plates
121
that encircle the neck section
112
. Each retaining plate
121
is formed with a boss
122
that projects radially and outwardly with respect to the shank
11
. The washer
13
is sleeved on the shank
11
, and the nut fastener
14
engages the threaded section
111
of the shank
11
.
With further reference to
FIG. 2
, in use, when mounting a bracket
10
on a wall
2
, a blind hole
20
, which has a diameter that corresponds to the outer diameter of the shank
11
when sleeved with the expansion sleeve
12
, is initially drilled into the wall
2
. Thereafter, with the expansion sleeve
12
disposed thereon, the shank
11
is driven into the blind hole
20
with the use of a mallet. By using a spanner to rotate the nut fastener
14
relative to the shank
11
, a torque is generated so as to create a force for moving the shank
11
outwardly of the blind hole
20
. At this time, movement of the shank
11
will cause the bosses
122
on the retaining plates
121
to engage the surface of the blind hole
20
. Also, since an increasing cross-section of the expander section
113
extends into the expansion sleeve
12
, the retaining plates
121
are forced by the expander section
113
to expand in a radial outward direction with respect to the shank
11
for engaging the surface of the blind hole
20
. Subsequently, the nut fastener
14
and the washer
13
are removed from the shank
11
, and the bracket
10
is disposed on the shank
11
. The nut fastener
14
and the washer
13
are again provided on the shank
11
for locking tightly the bracket
10
against the wall
2
.
Some of the drawbacks associated with the use of the aforesaid conventional wedge anchor
1
are as follows:
1. The surface of the expander section
113
of the shank
11
of the conventional wedge anchor
1
is smooth, and the expansion sleeve
12
is formed with only two retaining plates
121
having only two bosses
122
. Thus, when the nut fastener
14
is rotated, since the shank
11
is not held firmly in the blind hole
20
, it is possible that the shank
11
will rotate with the nut fastener
14
and will rotate idly inside the blind hole
20
due to inadequate gripping with the surface of the blind hole
20
. In addition, friction between the expander section
113
and the expansion sleeve
12
is relatively small. As such, due to lack of engagement between the expander section
113
and the expansion sleeve
12
, when the nut fastener
14
is rotated, there is also a possibility that the expansion sleeve
12
will rotate idly relative to the shank
11
, thereby preventing expansion of the retaining plates
121
.
2. As mentioned hereinbefore, the expansion sleeve
12
is formed from two interconnected retaining plates
121
that encircle the neck section
112
of the shank
11
. Because the arc lengths of the retaining plates
121
are relatively long, the retaining plates
121
are undesirably rigid and do not expand easily in the radial outward direction of the shank
11
. As such, the surface of the expander section
113
cannot be formed with an angle that is greater than 8° with respect to the axis of the shank
11
since the larger angle will hinder expansion of the retaining plates
121
. The smaller angle will result in a longer distance that is required to be traveled by the shank
11
or expanding the retaining plates
121
. Thus, the conventional wedge anchor
1
takes up a relatively long amount of time for fixing on the wall
2
.
3. Because a relatively long expander section
113
is needed to expand the retaining plates
121
, the shank
11
has a relatively large material requirement, thereby resulting in increased costs. In addition, a relatively long length of the shank
11
projects from the wall
2
due to the relatively long distance traveled by the shank
11
when expanding the retaining plates
121
. The relatively long projecting length of the shank
11
can hinder subsequent bracket mounting and locking operations.
SUMMARY OF THE INVENTION
Therefore, the object of the present invention is to provide a wedge anchor that can be driven quickly into a blind hole and that can ensure a stable securing effect.
According to the present invention, a wedge anchor includes a shank, a tubular expansion sleeve, and a nut fastener. The shank has a threaded section, a neck section extending forwardly and coaxially from one end of the threaded section, and having a diameter smaller than that of the threaded section, and an expander section extending forwardly and coaxially from one end of the neck section, and having a cross-section that gradually decreases along an axis of the shank in a direction toward the threaded section. The expansion sleeve is shorter than the shank and is sleeved on the neck section. The nut fastener engages the threaded section of the shank.
The expander section has a surface that forms an angle greater than 8° with respect to the axis of the shank, and is further formed with a plurality of longitudinal ribs that project radially and outwardly, that extend along the axis of the shank, and that are angularly spaced apart from each other. The expansion sleeve is formed with a plurality of a axially extending silts for engaging the longitudinal ribs on the expander section when the expander section is extended into the expansion sleeve. The slits configure that expansion sleeve with an annular base strip portion and the more than two retaining plates, each having a base edge connected to the base strip portion, a pair of parallel lateral edges, and a curved distal edge that interconnects the lateral edges and that curves forwardly in a direction away from the base strip portion. The lateral edges of adjacent ones of the retaining plates confine the slits. The curved distal edges of the adjacent ones of the retaining plates cooperate to form entrances into the slits. Each of the retaining plates is formed with a boss that projects radially and outwardly with respect to the shank.


REFERENCES:
patent: 2159580 (1939-05-01), Zifferer
patent: 4173918 (1979-11-01), Piersall
patent: 4436445 (1984-03-01), Templeman
patent: 4636123 (1987-01-01), Herg
patent: 5011337 (1991-04-01), Clark et al.
patent: 5228250 (1993-07-01), Kesselman
patent: 6270303 (2001-08-01), Gauthier et al.

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