CABLE REEL AND A METHOD FOR MANUFACTURING IT

DEVIDOIR DE CABLE ET METHODE DE FABRICATION

English Abstract

The object of the invention is a cable
reel, which includes a drum (2) made from
sheet steel and ends (1) i.e. flanges attached
to both sides. Curved tabs (4) are formed in
the ends (1) of the drum (2) and extending
in an axial direction through the ends (1),
to which tabs corresponding curved slots
(11) are formed. The parts of the tabs (4)
extending from these slots (11) beyond the
ends (1) are bent onto the external surface of
the ends (1). The length and width of the
tabs (4) in the direction of the circumference
are so great taking into account the thickness
of the sheet steel of the drum (2) and the
diameter of the drum that the deformation
work involved in bending the tabs due to
the curved tabs is many times greater than
compared to the bending of a straight tab. The
invention is also concerned with a method for
manufacturing the cable reel.

Claims

CLAIMS
1. A cable reel, which consists of a drum (2) with a
diameter of 150 - 1500 mm and made from galvanized sheet steel
with a thickness of 0,3 - 2 mm, ends (1) i.e. flanges attached
to both sides, and in which curved tabs (4) are formed in the
ends (1) of the drum (2), extending in an axial direction
through the ends (1), to which tabs corresponding curved slots
(11) are formed, the parts of the tabs (4) extending from these
slots (11) beyond the ends (1) being bent outwards onto the
external surface of the ends (1),
characterized in that the part of the tab protruding from the
end, i.e. the part to be bent is in length 7 - 20 mm, most
advantageously 9 - 12 mm, and that in the drum (2) sheet steel
is applied in such a way that the thickness s of the drum (2)
sheet, the width 1 of the tab (4), and the diameter D of the
drum (2) fill the following condition:
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in which case the length and width of the tabs (4) in the
direction of the circumference are so great, taking into account
the thickness of the sheet steel of the drum (2) and the diam-
eter of the drum, that the deformation work involved in bending
the tabs due to the curved tabs is many times greater when
compared to the bending of a straight tab.
2. A cable reel in accordance with Patent Claims 1 or
2, characterized in that the material of the end (1) is one of
the following: birch plywood, mixed plywood, particle board,
chipboard.
3. A cable reel in accordance with Patent Claim 1 or
2, characterized in that inside the drum (2) there is a support
disc (3) attached to the ends (1), which carries the drum (2)
over its entire circumference.

4. A cable reel in accordance with one of Patent
Claims 1 - 3, characterized in that the curved part of the drum
(2) between the tabs (4) that protrude through the ends (1)
penetrates the inner surface of the end (1).
5. A cable reel in accordance with one of Patent
Claims 1 - 4, characterized in that the thickness of the ends
(1) is 6 - 30 mm in a reel in which the diameter of the drum (2)
is 150 - 1500 mm.
6. A cable reel in accordance with one of Patent
Claims 1 - 5, characterized in that inside the drum (2) that is
actually intended for the cable there is an internal support
drum, which is also made from sheet metal and is attached to the
ends by means of tabs in its ends.
7. A method for manufacturing a cable reel in accor-
dance with Patent Claim 1, in which method a drum (2) manufac-
tured from sheet steel with tabs (4) formed in its ends, and
ends (1) manufactured from board in the circumference of which
curved openings (11) corresponding to the tabs (4) of the drum
(2), are joined to one another by pushing the tabs (4) through
the openings (11) in the ends (1) and by bending the protrusions
(14) against the surface of the end (1), characterized in that
the bending of each protrusion (14) is carried out by a wing-
shaped member (16), which is rotated over the circumference in
the same direction as it.
8. A method for manufacturing a cable reel in accor-
dance with Patent Claim 1, in which method a drum (2) manufac-
tured from sheet steel with tabs (4) formed in its ends, and
ends (1) manufactured from board in the circumference of which
curved openings (11) corresponding to the tabs (4) of the drum
(2), are joined to one another by pushing the tabs (4) through
the openings (11) in the ends (1) and by bending the protrusions
(14) against the surface of the end (1), characterized in that
the curved opening (11) in the end (1) are formed by die-cutting
a thin curved piece out of the board.

Description

~ W094/22755 1 21 5 9 7 2 ~ PCT/F~4/00130
CABLE REEL AND A METHOD FOR NANUFACTURING IT
The object of the invention is a cable reel, which includes a
drum and ends i.e. flanges attached to both sides, and in which
curved tabs formed in the ends of the drum and extending in an
axial direction through the ends are used in the attachment of
the drum and the ends, in which corresponding curved slots are
formed and the parts of the tabs ex~ ng beyond the ends are
bent onto the external surface of the ends. The invention is
also concerned with a method for manufacturing a cable reel.
Known cable reels are generally made from wood strips and
thicker wood. The end disks are manufactured from sheets of wood
strips laid crosswise. The drum is typically made from slightly
conical strips, from which a cylindrical component is formed.
The above manufacturing teGhn;que for large drums is time-
consuming and the drums have a considerable weight. This inven-
tion is mainly concerned with cable reels in which the drum
diameter is 150 mm or greater. Small cable reels are man~fac-
tured as one piece by either moulding or spray-pressing from
plastic, but this method is not suitable for large reels.
US publication 3,544,032 presents a cable reel of the type
referred to in the introduction. The tabs of the drum are fed
through openings in the ends and bent. Here the tabs are very
narrow and their protrusion is small. It does not require a very
great force to bend them, especially if the opening is in the
form of a triangle or rectangle. On the other hand, the puhli-
cation does not show means for h~n~; ng larger tabs.
The intention of this invention is a stronger cable reel than
previously, the manufacture of which is simple. The characteris-
tic features of the invention are presented in the accompanying
Patent Claims. The invention is to a great extent based on the
realization that essentially in bending each curved sheet-metal
part deformation work must be carried out, which on the other
hand the load would have to do in reverse in order to separate
the end from the drum. The deformation of the tabs locks them

W094/22755 21~ 9 7 2 S PCT/F~4/00130
effectively in place. The optimal deformation requires a precise
shape for the curved opening. Due to the great deformation work
it is advantageous and often essential to use a machine tool for
bending. This sweeps a local formation over the entire length of
the tab.
Other advantages and forms o~ application of the invention
appear in connection with the later examples of application. In
what follows the invention is illustrated by` reference to the
accompanying Figures, which show various cable reels in accor-
dance with the invention, as well as their components.
Figure l shows a drum and end before they are attached to one
another.
Figure 2 shows a f;~;~heA cable reel.
Figure 3 shows a detail of the cable reel in partial cross-
section.
Figure 4 shows a cross-section of the construction of an end.
Figure 5 shows a cross-section of the seam of the drum.
Figure 6 shows the m~ch~n;cal bending of the tabs.
Figure 7 shows the manufacture of an end by die-cutting.
The principal components of a cable reel are here two ends l and
2 and the drum 3 between them. The drum is most advantageously
manufactured from galvanized sheet steel, with a thickness of
O,3 - 2 mm, corresponding to drum sizes of 160 - 1200 mm. The
ends are most advantageously made from birch or mixed plywood,
but other strong boards, such as particle board or chipboard,
may be considered. The manufacture of the cable reel begins by
cutting an essentially rectangularly shaped piece of sheet
steel, on both edges of which indentation are cut in order to
make tabs 4. The bends to be made for seam lO appear later. The
drum in accordance with Figure l is bent from the sheet and the
seam l0 is secured. At the same time disc l is made from birch
plywood in which the curved openings ll are formed. Manufacture
takes place most advantageously by die-cutting in accordance
with Figure ~, which is dealt with later in detail.

~ W094/~755 215 g 7 ~ ~ ~CT/F94/00130
Alternatively holes are drilled at the start of the curves and
the required curves are cut with a fretsaw with the aid of a
jig. After this the end 1 and the drum are joined together, the
tabs 4 are pushed through the curved openings 11, and the ends
are pressed against the drum, after which the ends of the tabs
4 are pressed against the outside of the end 1 by means of a
hydraulic press. Figure 6 shows the tool 15 and the method of
operation, by means of which the ends 14 of the tabs 4 are bent.
The head of the tool 15 that forms the tabs has a wing shape,
when the bending takes place gradually during the rotation of
the tool. Compared with ben~; ng that takes place at once less
force is required, because the forming is limited at each moment
locally to a quite small area.
Figure 2 shows a finished drum, in which the fold 14 of the tab
4 onto the outer surface of the end 1 can be seen. In addition.,
the Figure shows in broken lines a support disc 3, which, if
addition strength is required, can be attached to the end disc
1, before the drum 2 is attached to it. In accordance with
Figure 3 the support disc 3 carries the drum over its entire
circumference and thus provides the construction with addition
breaking strength.
Figure 4 shows the joint between the drum 2 and the end 1 in
detail. Here too the support disc 3 is visible. The tab 4 has
been pushed through the curved opening 11 of the drum and its
end has been turned, when the folds 14 can be seen against the
end 1.
The cable reel with its cable can be advantageously protected by
means of a sheet metal cover 8, in each edge of which a groove
9 is formed. This is made from an essentially rectangular piece
of sheet metal, which is formed into a cylindrical cover around
the drum. By means of the groove in the edges the cover stays
firmly in place. The ends include suitable locking devices, e.g.
foldable tabs, by means of which the sheet is made to remain on
top of the drum.

W094/22755 215 9 7 2 5 PCT/FW/00130 ~
The tabs of the drum extend advantageously 9 - 12 mm from the
end. In any event the protrusion is between 7 - 20 mm. In
general tabs longer than 12 mm remain "grinning" above the
surface of the end, because the stress -created during the
bending does not really extend beyond 10 mm. Forming carried out
by means of device in accordance with Figure 6 pulls the tabs
outwards, in which case the curved parts of the drum 2 between
the tabs bit into the inside surface of the ends. It is possible
to make small curved grooves for them if it is desired to
increase the load- bearing capacity in this area. In any case
the curved parts cut more or less into the inner surface of the
ends, creating a support for the drum over the entire circum-
ference.
The seam 10 of the drum 2 is formed by overlapping the ends of
the metal sheet in such a way that bend 5 is formed in the sheet
that remains underneath, by means of which places itself easily
under the opposite end of the sheet in accordance with Figure 5.
The ends of the sheet are secured ~o one another by point
welding 6, when a strong and even seam 10 is obtained.
In some manufactured cable reels dimensions of the following
type were used. A cable reel with a diameter os 500 mm, in which
a 240 mm drum was used was manufactured as follows. 0,7 mm thick
galvanized steel sheet was used in the drum and 15 mm thick
birch plywood in the ends. There were four tabs and they had a
length of 100 mm (curved dimension). A 1500 mm diameter end was
manufactured from 25 mm thick birch plywood and the 1100 mm drum
in it was made from 1,25 mm galvanized sheet steel. There were
eight tabs and these had a length of 100 mm.
In a drum of diameter of 150 - 1500 mm galvanized sheet steel,
with a thickness of 0,3 - 2 mm is used, adapted in such a way
that the thickness s of the sheet of the drum 2, the width 1 of
the tab 4, and the diameter D of the drum 2 fill the following
conditions: 3, 5 1 < D < 9 1
mm2 s2 1 ~I~m2

21~9~2~
~ W094/22755 PCT/F~4/00130
The protrusion of the tab is the abovementioned 9 - 12 mm. In
cable reels in accordance with this the curve of the tabs causes
a considerable deformation requirement. On the other hand, the
finished bend resists considerably larger loadings than
previously.
Compared with the b~n~; ng of a flat sheet, the bending force
required to bend the entire tab at one time increases many
times, to become at least 15 times greater. In general the force
required would be still greater than this, for which reason it
is better to bend the tab by means of local forming, which is
carried out by means of sweeping over the tab in the manner
shown in Figure 6.
Inner discs are used in drums with a diameter of 600 mm or
greater, though it is possible to replace them by increasing the
material thickness in both the drum and end boards. In these too
an inner drum can be used, if it is desired to further
strengthen the construction.
In the method of making the end in Figure 7 a longitl~in~l blank
22 is moved through die 16, which cuts the ready end boards 1
from it. The die 16 consists of a fixed lower section and upper
part that strikes against it, of which only the cutting blades
are drawn visibly. Openings for the tabs are formed by striking
the upper curved blade 18 aga-inst the curved opening blade 17 of
the lower part. A thin curved piece is removed through the lower
blade 17. At the time the entire end disc can be die-cut from a
blank board by means of blade 19. If required a centre opening
21 can be formed by the same strike with blade 20.

Representative Drawing