Note: Descriptions are shown in the official language in which they were submitted.
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METHOD OF FORMING AN EXPANSION MOUNTING SLEEVE
AND THE PRODUCT THEREOF
FIELD OF THE INVENTION
he present invention relates to an expansion mounting sleeve, and
p1ore particularly to an expansion mounting sleeve that can be driven or
,inounted in a hole on a wall and be expanded to firmly locate in the
hole when a matching ready-made bolt is screwed thereinto.
BACKGROUND OF THE INVENTION
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The currently commercially available expansion bolt assemblies and
associated mounting nuts are manufactured in different manners, such
as injection molding plastic materials, casting zinc, lead, or aluminum
lloys, turning cutting rods to form bolts and cold forging pipes to form
lexpansion sleeves, and cold forging rods to form bolts and stamping
0eet metal to form expansion sleeves.
AIl these conventional expansion bolt assemblies and mounting nuts
jrequire complicate processing apparatus and a lot of parts, as well as
~elatively high quantity of material to produce them. And, the
oonventional expansion bolt assemblies or mounting nuts tend to fail in
astening because the expansion sleeves thereof fail to expand as
esired, causing the bolts or the mounting nuts to idle without being
ightened against the expansion sleeves.
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ig. 1 shows a first conventional expansion mounting screw assembly
ormed from a plastic material. The plastic expansion screw assembly
as the advantages of low material cost and resistant to rust, but
equires high cost for molds and has low production speed. The plastic
expansion screw assembly also has low rigidity as well as small
ngaging friction with wall, and accordingly, weak tensile strength and
earing strength. Therefore, the expansion sleeve of the plastic
expansion mounting screw assembly tends to be easily pulled out of the
wall.
The conventional expansion mounting nuts cast by alloys require longer
~ime to produce and involve a lot of tools and processing procedures,
including tapping, assembling, etc. The major disadvantages of the
cast alloy expansion mounting nuts include a limited range of usable
materials and a mechanical strength lower than the products made of a
cold-rolled metal strip material.
Pig. 2 shows a conventional turning cut expansion sleeve or mounting
ut for an expansion bolt assembly, which requires longer time to
Oroduce a primary body and form grooves on the primary body in
secondary processing. A lot of material is waste in turning cut. The
urning cut expansion sleeve must be used with a taper-headed bolt to
chieve the expansion of the sleeve. Another disadvantage is the
tuning cut expansion sleeve is often made of high speed steel, which
has a resistance too high to allow successful expansion of the sleeve,
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resulting in idling of the bolt or the nut against the expansion sleeve
ithout effectively achieving the fastening operation. This type of
xpansion bolt assembly is therefore not suitable for use in assembling
ork pieces, erecting construction works, or assembling DIY
do-it-yourself) products.
=conventional expansion bolt assembly including a cold-forged metal
bolt and a turning cut metal sleeve is currently most widely used in
civil works, restoration, hanging, equipment installation and positioning,
~tc. The bolt is taper-headed, and the sleeve is processed to form slits
hereon. This type of expansion bolt assembly also includes a flat
wash, an expansion washer, and a nut, and may be handled in two ways.
n the first way, first moves the nut to a rear end of the bolt, then, drive
he expansion bolt assembly into a hole pre-drilled on a wall surface,
4nd then tighten the nut, so that the taper-headed bolt expands the
forced forward slit sleeve. The sleeve of this type of expansion bolt
4ssembly frequently fails to expand due to a high resistance, resulting
n idling when the nut is tightened against the bolt. In the second way,
iirst move the nut to a rear end of the bolt, then, drive the expansion
bolt assembly into a hole pre-drilled on a wall surface, and then release
he nut and the expansion washer from the bolt. Thereafter, use a
leeve larger than the bolt to force the slit metal sleeve forward, so that
apered head of the bolt forces the slit metal sleeve to expand and
achieve the purpose of tightly fastening the expansion bolt assembly to
e wall. However, since the pre-drilled hole is often incorrect in
epth, or biased, or too soft at the bottom thereof, the metal sleeve
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ends to move too much forward or the bolt tends to idle. In addition,
his type of expansion bolt assembly includes a lot of associated parts
nd requires good skill to handle it to avoid failure in mounting it.
ig. 3 shows a further conventional expansion bolt assembly that is an
iMproved version of the above-described type of expansion bolt
ssembly, and mainly includes a cold-forged bolt and an expansion
leeve formed by stamping. Forming the expansion sleeve by stamping
may advantageously reduce the manufacturing cost and lower the
Osistance to expansion so as to increase the engaging friction of the
sleeve with the wall. The stamped expansion sleeve is expanded by
~rcing or screwing the taper-headed bolt into the sleeve. This
i proved type of expansion bolt assembly still has the drawbacks of
i cluding too many parts and requiring longer time to assemble the
pJarts together.
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If is therefore tried by the inventor to overcome the drawbacks existed
io the conventional expansion bolt assemblies by developing an
i#dependent expansion mounting sleeve formed by stamping using
p ogressive dies through simple and less processing procedures, so that
t e expansion mounting sleeve has the advantages of requiring less
n1aterial to form it, having an internally threaded bore to ensure tight
s~rewing of a matching ready-made bolt into it to expand the sleeve
ithout the risk of idling, having a plurality of differently sized and
s aped and outward protruded engaging teeth to ensure firm and
f'ctional contact of the expanded sleeve with the wall without the risk
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f becoming loosened or being pulled out, and largely reducing the
ools and costs for manufacturing it.
SUMMARY OF THE INVENTION
A primary object of the present invention is to provide an expansion
niounting sleeve that can be quickly manufactured using a variety of
i~aaterials with reduced material quantity through simple processing
Procedures.
Another object of the present invention is to provide an expansion
piounting sleeve that can be conveniently used with a ready-made bolt
llaving matching length, size, and screw threads; so that the apparatus
4nd tools needed to produce the expansion mounting sleeve can be
l~rgely simplified.
~ further object of the present invention is to provide an expansion
"nting sleeve that can be easily handled by a person with general
slkill to successfully complete the fastening work within a shortened
t~me period.
A still further object of the present invention is to provide an expansion
nhounting sleeve that could be efficiently driven into or mounted in a
wall without the risk of becoming loosened.
~o achieve the above and other objects, the expansion mounting sleeve
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pf the present invention includes a forward tapered cylindrical body
ormed by stamping and pressing a cold-rolled metal strip to define an
nternally threaded tapered bore. A plurality of engaging teeth having
ifferent heights and shapes are formed to project from the cylindrical
body. After the sleeve has been driven into or mounted in a hole
Pre-drilled on a wall, a ready-made bolt having length, size, and screw
hreads matching the threaded bore of the cylindrical body may be
$crewed into the bore and thereby expands the forward tapered
Oylindrical body of the sleeve, causing the engaging teeth to extend
butward and tightly engage with the wall in the hole, so as to firmly
4old the expansion mounting sleeve in place in the hole.
The expansion mounting sleeve of the present invention is formed by
stamping and pressing using progressive dies. A method of
alanufacturing the expansion mounting sleeve includes the following
steps:
~a) preparing a piece of material having dimensions needed to
manufacture the expansion mounting sleeve, forming at least two
t4pered areas on the material, and defining thread forming areas on the
rpaterial;
('b) pressing the material to form more than one slot in the thread
fbrming areas, such that the slots are parallel to an axis of the material;
(I~) pressing the material to form at least one barb and/or more than one
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utward protruded engaging teeth in each of the tapered areas, the
ngaging teeth have heights that increase toward a front end of the
rriaterial;
~d) pressing the material to form screw threads of a desired size in the
thread forming areas;
e) pressing the material to form at least one degree of bending at the
(i
t,apered areas;
(~f) pressing the thread forming areas to form a U-sectioned shape;
('Ig) further curling the thread forming areas into a circular cross section;
4nd
(h) trimming off unnecessary temporary connecting material belt to
domplete one unit of the expansion mounting sleeve.
BRIEF DESCRIPTION OF THE DRAWINGS
The structure and the technical means adopted by the present invention
tb achieve the above and other objects can be best understood by
roferring to the following detailed description of the preferred
cmbodiments and the accompanying drawings, wherein
~
Iiig. 1 is a perspective view of a conventional expansion mounting
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crew assembly;
ig. 2 is a perspective view of a sleeve of another conventional
xpansion bolt assembly;
ig. 3 is a perspective view of a further conventional expansion bolt
gssembly;
Fig. 4 is a perspective view of an expansion mounting sleeve according
tb a preferred embodiment of the present invention;
Fig. 5 is a perspective view of the expansion mounting sleeve of Fig. 4
v`rith a bolt screwed thereinto;
Pigs. 6 to 9 show the manner of screwing a bolt into a wall surface via
the expansion mounting sleeve of the present invention;
Pigs. 10A to 10H show the steps included in a method of forming the
dxpansion mounting sleeve of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Please refer to Fig. 4 that is a perspective view showing an expansion
mounting sleeve 10 according to a preferred embodiment of the present
invention. A bolt 40 having suitable length, size, and screw threads for
s~rewing into the expansion mounting sleeve 10 is also shown in Fig. 1.
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ig. 5 is a perspective view showing the expansion mounting sleeve 10
ith the bolt 40 screwed thereinto. As shown, the expansion mounting
leeve 10 includes a substantially straight cylindrical body formed by
urling a metal material. A locking means 60 is formed at a joint of
wo edges of the curled metal material near a rear end of the cylindrical
ody of the expansion mounting sleeve 10 by way of stamping. The
1 cking means 60 includes an ear section 61 protruded from one of the
tllwo joining edges, and a recess section 62 formed on the other joining
4dge opposite to the ear section 61 for engaging with the latter and
tl~ereby lock the two joining edges together (also refer to Fig. l0A).
~he cylindrical body of the sleeve 10 defines a bore 12, which is
i~ternally provided with a plurality of screw threads 14. The
ylindrical body and the bore 12 of the sleeve 10 are tapered toward a
f~ront end the sleeve 10, and at least one engaging tooth 16 is projected
~rom an outer surface of the sleeve 10. In the illustrated embodiment,
plurality of engaging teeth 16, 17, 18 having different lengths and
shapes are projected from the outer surface of the sleeve 10. Moreover,
one or more stopping tooth areas 20 are formed on the cylindrical body
~f the sleeve 10 (see Fig. 6).
Oigs. 6 to 9 are sectional views and partially sectioned views showing
tl~e manner of fastening a bolt to a hole 51 on a wall 50 via the
e pansion mounting sleeve 10, and the state in which the expansion
ounting sleeve 10 is firmly pressed against an inner surface of the
h le 51. As shown, the wall 50 is pre-drilled to provide the hole 51 for
fitly receiving the expansion mounting sleeve 10 therein. Then, a bolt
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40 having length, size, and screw threads matching the internal screw
t reads 14 is screwed into the bore 12 of the sleeve 10. When the bolt
0 is moved forward along the screw threads 14, it also pushes against
t e forward tapered bore 12, and thereby forces the forward tapered
ylindrical body of the sleeve 10 to expand outward. At this point, the
engaging teeth 17, 18, 19 are caused by the altered taper of the sleeve
to move outward like a stretched umbrella and therefore tightly
e~ngage with the wall of the hole 51 and hold the sleeve 10 in place in
t~e hole 51.
Thhe expansion mounting sleeve 10 of the present invention is formed by
s~amping using progressive dies. Figs. l0A to lOH show in concrete
tlie steps of forming the expansion mounting sleeve 10. First, prepare
a; material having dimensions required to produce the expansion
mounting sleeve 10, and then form two or more tapered areas 22 on the
niaterial, as shown in Fig. IOA. Then, press the material in pre-defined
t~read forming areas 24 to form one or more slots 26 parallel to an axis
of the material, as shown in Fig. IOB. Then, press the material again
tO form a barb 30 and/or more than one engaging tooth 16, 17, 18 in the
t pered areas 22. It is noted the engaging teeth 16, 17, 18 have
d fferent heights which increase toward a front end of the tapered areas.
T e engaging teeth 16, 17, 18 are then bent toward an outer side of the
aterial, as shown in Fig. IOC. Thereafter, press the material at the
t read forming areas 24 to form screw threads 14 having a required size,
a shown in Fig. I OD. The material is then pressed at the tapered areas
2 to form at least 1 degree of bending, as shown in Fig. 10E.
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fter the above steps are completed, the material is further stamped, so
at the thread forming areas 24 are pressed into a U-sectioned shape,
s shown in Fig. IOF. Then, the thread forming areas 14 are further
urled, so that the whole material has a cross section approximate to a
ircle, as shown in Fig. IOG. When the thread forming areas 24 are
Ily curled to form a cylindrical body having a circular cross section, a
lpcking structure 60, which consists of an ear section 61 and a recess
s'Iection 62 correspondingly formed at two opposite edges of the material
~ear a rear end thereof, is locked to hold the curled material in the
~rmed cylindrical body, as shown in Fig. IOH. Finally, trim off the
t~mporary connecting belt of material to obtain a finished product of
t~e expansion mounting sleeve 10.
*om the above described steps, it can be found that the expansion
n~ounting sleeve 10 of the present invention is integrally formed by
e~nploying the existing well matured stamping and press forming
t~chniques and designing high-precision progressive dies, and using the
v~idely available materials. The expansion mounting sleeve 10 has the
fgllowing advantages:
(~) The locking structure 60 effectively prevents the rear end of the
cylindrical body of the sleeve 10 from being expanded and
becoming loosened when the bolt 40 is screwed into the screw
threads 14 from the rear end of the sleeve 10.
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i
) The one or more stopping tooth areas 20 effectively prevent the
sleeve 10 mounted in the hole 51 from rotating when the bolt 40
is initially screwed thereinto.
(I3) Since the bore 12 of the sleeve 10 is internally threaded, and the
bore 12 and the cylindrical body of the sleeve 10 are forward
tapered, the bolt 40 of right size screwed into the sleeve 10 along
the threads 14 would finally expand a front portion of the sleeve
into a fully straight cylindrical shape, and cause the engaging
10 teeth 16, 17, 18 to move outward like a stretched umbrella to
tightly engage with the wall 50 in the hole 51, and thereby firmly
hold the sleeve 10 in place in the hole 51.
(4) The sleeve 10 is integrally formed by stamping through easy and
quick processing procedures. A variety of usable materials may
be selected for manufacturing the sleeve 10 without
unnecessarily wasting the material. The associating bolt 40 may
be an easily accessed ready-made bolt to facilitate 100%
successful fastening operation using the bolt 40 and the
expansion mounting sleeve 10 within shortened time period at
reduced product and labor costs.
(¾) The expansion mounting sleeve 10 may be integrally formed by
stamping a cold-roIled metal strip using high-precision
progressive dies at high productivity.
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(6) The material for the expansion mounting sleeve 10 may be
selected according to different applications. Among others, the
widely available metal material can be conveniently used.
7) The expansion mounting sleeve 10 is integrally formed by
stamping a cold-rolled metal strip to simplify the manufacturing
procedures and largely save the material, compared to various
kinds of metal expansion bolt assemblies or mounting nuts
manufactured using conventional processing techniques, such as
turning, cold forging, etc. For example, in the turning cut
expansion bolt assembly, a round bar must be turning cut and
then subjected to a secondary processing of grooving to form an
expansion sleeve, and a taper-headed bolt is cold forged to use
with the sleeve; and in the cold forged expansion bolt assembly,
a round bar must be cold forged to form a taper-headed bolt,
which is then used with other parts; and in the turning cut
mounting nut, a round bar must be turning cut.
('8) The expansion mounting sleeve 10 is made to use with
ready-made bolts and screws. All bolts or screws having length,
size, and screw threads matching the internally threaded bore 12
of the sleeve 10 may be selected for use. The sleeve 10 of the
present invention is therefore superior to the conventional
expansion bolt assemblies in terms of the compatibility of the
sleeve with the bolt.
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(9) It is very easy to use the expansion mounting sleeve 10 of the
present invention to fasten a bolt or screw to a wall. To do so,
simply drive the sleeve 10 into the hole 51 predrilled on the wall
50, and select a matching bolt or screw 40 to screw into the
sleeve 10. A person of general skill may handle the sleeve 10
and the bolt 40 to complete the fastening operation within a short
time.
(10) The expansion mounting sleeve 10 is firmly mounted in the hole
51 on the wall 50 when the bolt 40 is screwed into the threaded
bore 12 of the sleeve 10 to expand the tapered front portion of
the sleeve 10, which in turn causes the engaging teeth 16, 17, 18
to move outward and tightly engage with the wall 50 to hold the
sleeve 10 in place in the hole 51. The sleeve 10 mounted in the
hole 51 in this manner is absolutely prevented from idling or
loosening in the hole 51.
(11) Since the sleeve 10 is in the form of a female member, the
matching bolt 40 in the form of a male member does not project
from the rear end of the sleeve 10 when the fastening operation
is completed, giving the wall a visually pleasant surface and
ensuring the tight attachment of the expansion mounting sleeve
10 and the bolt 40 to the wall 50.
In brief, the expansion mounting sleeve 10 of the present invention can
~e manufactured by integral stamping through simple and quick
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Orocessing procedures. And, a variety of usable materials may be
4elected for manufacturing the sleeve 10. The bolt 40 for using with
~he sleeve 10 may be easily accessed from the ready-made products.
And, the sleeve 10 may be efficiently driven into or mounted in a wall
Itiivithout the risk of becoming loosened from the wall.
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