Note: Descriptions are shown in the official language in which they were submitted.
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Back~round of` the invention
The present invention relates to a method of
packaging needlelike magnetic metal pieces such as ~teel ~-
fibers.
Steèl fibers which are used ~or reinforcing concrete
materials and the like are packaged and conve,yed in a
container to a ~ite where they are used~ In thi9 ca~e,
the æteel fiberæ in the packaging container are directed
at random and entangled with one another~ The follow-
~D ing are the chief drawbacks resulting ~rom the steel fibersbeing kept in such conditions during their transportation
~ and up to the point of the~mixing of concrete:
,1 (1) The ~oid of the packaged material is high and thus
;, the use of a largè container is required with the
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; resulting increase in the packaging and transporta~
tion oosts,- For instance, a container of 40 X;27 `~
, ~ X 24 cm (25.92 e) is necessary to oontain 20 Kg of
, ;
- steel fibers of 0.5 X 0~5 X 30 mm,
(2) Due to the~Yibrations during the transportion? the
entangle~ steel ~ibers are fastened together and
compacted as such, thus making it difficult to ~;
unravel the~ entangled~st~eel fibers so that the steel
fibers can be used, ~hus~ it is necessary to use
a separate steel fiber dispenser,
(3) During the~;transportati~n9 the steel fibers are
fastened~together and compacted thus reduclng the ~ ;
entire ~olume and deterloratlng the appearance as
a commodity. -~
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SU~IMARY OF 'I'~IF. INVENT[ON
It i9 the object of the present inven~ion to provide
a packaging method whereby in packing needlelike magnetic metal
pieces such as steel fibers, the needlelike metal pieces are
packed into a container in such a manner that the needlelike
metal pieces are substantially arranged in the same direction
thus improving the packing ratio and moreover there is no
possibility of the needlelike metal pieces being fastened to-
gether tightly thus reducing the apparent volume and there is
practically no need to resort to any dispensing operation at
` the time of use.
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The present invention i5 defined as a method of -~
packaging needlelike magnetic metal pieces by feeding said ;
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pieces into a container made of non-magnetic material to
produce a substantially parallel magnetic flux in said container
~ characterized in that said needlelike magnetic metal pieces
-¦ being steel fibers for use with steel fiber reinforced concrete
which contains less than 0.1% carbon and said magnetic flux
being produced intermittently and at least thrice during the ;~
time in which said steel fibers are fed into said container by -
~, switching off and on a current flowing in an electromagnet having
a pair of opposed magnetic poles, each of said poles having a
pole face substantially equal to the area of an opposite side
of said container.
BRIEF DESCRIPTION OF THE DRAWING -
Figure l(a) is a schematic diagram oseful for explaining
;ll a preferred embodiment of the present invention.
Figure l(b) is a schematic diagram showing the ~ -
orientation of the steel fibers in a container when the
~- 30 magnetic flux is extinguished in the embodiment of Figure l~a). -~
Figure l(c) is a schematic diagram showing the
~ orientation of the steel fibe-rs in the container after the
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-~ completion of th~ packLng oE the steel fiber~ into ~he contalner
in the embodiment of ~igure l(a).
Figure 2 is a schematic dlagram showing a modified
form of the embodiment of Fig~re l~a).
Figure 3 is a schematic diagram showing another
preferred embodiment of the present invention.
DETAIIED DESCRIPTION OF THE INVE~TION
The method of this invention will now be described
with reference to the drawings. In the following des-
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crlption of the embodiments of the present invention,the needlelike magnetic metal pieces consist of steel
fibers. As shown in the drawings, steel fibers 1 ar~
fed into a container 2 through a feed pipe 4 ~he
container 2 is made of a non-magnetic material such as
paper, wood or plaætic material. In the method of
this invention, magnetic flux which is substantially
parallel horizontally is produced in the container 2. ~ ~
In the e~bodiments shown in Figs. 1 and 2 the magnetic ~ --
flux is produced during the time that the steel flbers
are being packed into the container, while in the embodi-
ment shown in Fig. ~ the maenebic ~lux is praduced a~ter
the steel fibers have been packed inbo the contalner.
In the embodiment æhown in~Fig, 1, the magnetlc
poles N and S of a bipolar electromagnet 3, each~having
a pole~face substantially equal bo the area of each side
of the eontalner 2,~are externally opposed to each other
on the opposed sides o~ the container 2. The steel
fibers 1 are fed from above into the container 2 through
,
the feed plpe 4. ` `
Firstly, wit4 a current interrupter 5 for the bipolar ; --~
electromagnet 3 turned on, when the steel fibers 1 are ` ; `
fed lnto the contalner 2 through the feed pipe 4, the steel ~`
fibers 1 are aligned and orientated in the electrode direc-
tion by vlrtue of;the magnetlc flux~which~has been produced ;~
substantially parallely in t~e horizontal direction in
the container 2. At this tlme~, though the steel fibers
ln the container 2 are orientated in the æame direction
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as shown in ~ig. l(a), the steel fibers are not arranged
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closely as yet as shown in the Figure l(a). Though it
is possible to closely pack the steel fibers together
by pressing down and compressing the steel fibers, this
process is not desirable since it tends to make the
packaging apparatus more complicate. On the other hand,
the downward movement o~ the steel fibers contacting with
the inner side o~ the container 2 are impeded by the ;~
~rictional force and the steel fibers as a whole are
shaped into a form having a central depression as shown
in Fig. l(a). This tendency ténds to become more marked
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with increase in the amount of steel fibers fed.
According to the present embodiment, the current
interruptor 5 for interrupting the flow of ourrent in
the electromagnet 3 is turned off at suitable intervals
to extinguish the magnetic field in the container~2.
At this time, the feeding of the steel ~ibers is also
temporarily stopped. ~When the current is~swltched off, '~
the steel~fibers 1 in the container 2 ~all downward in the
above-mentioned ~orm~and settle into a closely arranged
form with a slight depression formed in the central
portion as shown in Fig. l(b). It is necessary to
switch of~ the current only for a very short period o~
time. ~hereafter, the current lnterrupter 5 is turned
on again and the feeding of the steel fibers is resumed
~.
so that the newly fed steel fibers fill the previously
formed depression and are~further arranged and orientated ~
thereon in the~like manner. ~ ~hls process is repeated ~`
to ~eed the stael flbers into the container 2 until the ;~
container 2 is filled wlth the steel fibers.
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The resulting condition is shown in Fig. l(c). During
the time interval between the beginning and end of feed-
ing of the steel Eibers~l, it is necessary to turn off
and on the current flow at least twice. If the cùrrent
flow is not turned off and on at all or the current flow
is turned off and on only once, the resulting central
depression will be so great that it is impossible to fill
the container with the steel fibers which are arranged
closely enough on the whole.
The second embodiment shqwn in Fig. 2 differs
from the embodiment of Fig. 1 in that a pair of elect~o-
magnets 3a and 3b are used in place of the bipolar electro~
magnet 3. A current flow is caused bhrough the electro-
magnets 3a ànd 3b and the magnetic flux which is substan-
~- tially parallel horizontally is produced in the container
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2 from the north pole of the electromagnet 3a to the south
pole of the electromaynet 3b. In this way, the distance/`-
between these magnetic poles (N and S) can be easily varied
in accordance with the-size of the container 2. The con-~ :
tainer 2 is placed on a weighing machine 6.
, The third embodiment shown in Fig. 3 differs from
the embodiment of Fig. 1 in that after the steel fibers
1 have been ~ed into the container 2 by way of the feed
pipe 4, the container 2 is transferred into the core of
a cylindrical ele~omagnet 3c and the steel fibers 1
are orientated and closely arranged by means of the -
magnetic flux produced in the container 2 substantially
parallely in the horizontal direction. In this case, `
` forced vibrations are simultaneously caused in the contai-
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ner 2 by a vibrator 7 -thus facilitating the orientation ~-
and close arrangement of the steel fibers. After the
orientation of the steel fibers has been completed, the
container 2 is removed ~rom the core of the cylindrical
electromagnet ~c and it is then wrapped for shipping.
- In this embodiment, o~ course it is possible to use abipolar electromagnet in place of the cylindrical electro-
magnet in the similar manner as in the embodiment of
Fig. 1.
D Another additional feature of the embodiment
shown in ~ig. 3 is the fact that the steel fibers 1
: :1
,~ fed into the container 2 are subjected -to a preliminary
! orientation by passing them through a magnetic field
, wherein the magnetic flux is~passing in the direction of
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movement of the~steel flbers.~ In other words,~he feed
i~ ~ plpe 4 whloh is made of a non-magnetlc materlal such as
-~ ~ plastic~is extended through~a cylindrical~electromagnet
~, 3d, supported on a fulcrum 8 and rnechanically vibrated
;, by a hexagonal bar 9. Thus, when the steel fibers 1 are fed through the feed plpe 4, the steeI fibers 1 are
passed -throu~h the magnetic field of the electromagnet
3d in which the magnetic flux passes in the~direction of
movement o~ the steel fibers and the steel fiber~ are also
subjected to mechanical vibrations, with the result that
the steel fibers 1 thus preliminarily orientated fall
,
~; as such into the~container ~ and in this way the orlen-
tation of~the steel fibers 1 in the container 2 is ensured
more positively.
- With the method of this invention performed by the
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arrangements described above, there is an advantage that
needlelike magnetic metal pieces such as steel ~ibers
can be arranged to assume the same direction and packed ~: :
closely in the container9 reducin~ the costs of paokaging
and transpor~ation, eliminating the danger of the steel
fibers being fastened together tightly and deteriorating
the appearance, and eliminating the necessity of using a ;
large dispenser for unraveling the æteel fibers on the ~;
site to put then in use.
Anothor advantage is that when steel fibers of
soft magnetic material containing less than 0.1 ~ o~
carbon are used, the steel fibers removed ~rom the magne-
tic field has practically no residual magnetism.
The steel ~ibers packaged by the method o~ this ~
invention are useful for use as reinforcing fibers for ~ ~-
concrete. However, the method of this invention cannot
be used.with glass~fibers9 carbon fibers,~ monel fibers~
etc., which are slmilarly usable as concrete reinforcing
fibers as the steel fibers. ;~
While the method of this invention has been des-
cribed as ~ainly applied -to the packagil1g of steel fibers,
of cour9e the method o~ this invention can be used with
other needle}ike magnetlc metal pieces, such aS 9 needles, ~ ?
nails, etc. ~ ~
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Description of the prefsrred~embodlment ~ ~
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The following exampIe shows the results obtained
~5, by performing the~ method of this invention with the
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arrangement shown in Fig. 1.
a) Required voltage and current 160V, 3 - 4 A
b) Magnetic field 600 ~ 800 gaus~
,~
c) Size of container 24 X 1~ X 30 om
d) Volume o~ container about 10 ~
e) St~el fiber TESUSA (~radename of Nippon
Kokan K. K.) '
Size 0.5 X 0O5 X 30 mm
Composition
C = 0.05 %, Mn = 0.~ %, ~-
P - 0~014 %J S = 0.013 %
~,~ f) Packed weight 20 Kg
~,~ g) Weight per unit volume 2 Kg/ e
As compared with the weight per unit volume of : ~. .
;~ 0.77 Kg/e whloh was obta~lned by~the oonventional method -
of packing the stee} fibers lnto~the container at random,
the metho~d of the~present invention could pack the
steel ~ibers into the container about 2.6 times more
olosely~. ~Moreover, the carbon content of the steel
ibers used was less than 0.1 ~o and there was practically
no residual magnetism. ~.
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