U.S. patent number 3,664,108 [Application Number 04/843,664] was granted by the patent office on 1972-05-23 for intermediate storer for apparatus for stranding a twisted unit of a cable.
This patent grant is currently assigned to Siemens Aktiengesellschaft. Invention is credited to Klaus Hascher, Alfred Strelow.
United States Patent |
3,664,108 |
Strelow , et al. |
May 23, 1972 |
INTERMEDIATE STORER FOR APPARATUS FOR STRANDING A TWISTED UNIT OF A
CABLE
Abstract
An intermediate storer positioned between a take up point for
forming a twisted unit from cable elements and a pay out point
engages and rotates the twisted unit about an axis of rotation a
number of twists and provides a different direction of stranding of
the twisted unit for individual section lengths. A take up reel at
the take up point supplies the twisted unit to the storer in the
direction of the axis of rotation of the storer and a pay out reel
at the pay out point and on the axis of rotation removes the
twisted unit from the storer in the direction of the axis of
rotation.
Inventors: |
Strelow; Alfred (Berlin,
DT), Hascher; Klaus (Berlin, DT) |
Assignee: |
Siemens Aktiengesellschaft
(Berlin and Munchen, DT)
|
Family
ID: |
25603586 |
Appl.
No.: |
04/843,664 |
Filed: |
July 22, 1969 |
Foreign Application Priority Data
|
|
|
|
|
Jul 23, 1968 [OE] |
|
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A 7117/68 |
Jul 23, 1968 [OE] |
|
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A 7118/68 |
|
Current U.S.
Class: |
57/294; 57/66;
57/59 |
Current CPC
Class: |
H01B
13/0242 (20130101); D07B 3/005 (20130101) |
Current International
Class: |
D07B
3/00 (20060101); H01B 13/02 (20060101); H01b
013/04 () |
Field of
Search: |
;57/34,34AT,59,66,66.5 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Petrakes; John
Claims
We claim:
1. An intermediate storer arrangement having an axis of rotation
and being rotatably mounted for rotation about the axis of rotation
for stranding stranded cable elements of a cable into a twisted
unit having alternating stranding directions in successive sections
of length, said intermediate storer arrangement comprising an
intermediate storer having an axis transverse to the axis of
rotation of the intermediate storer arrangement, a single take up
reel having a roller surface tangential to the axis of rotation of
the intermediate storer arrangement for supplying the twisted unit
to the intermediate storer in a direction of the axis of rotation
of the intermediate storer arrangement in a plurality of windings
substantially parallel to a plane including the axis of rotation of
the intermediate storer arrangement, and a single pay out reel
having a roller surface tangential to the axis of rotation of the
intermediate storer arrangement for removing the twisted unit from
the intermediate storer, said intermediate storer comprising a disc
having a storage surface for said twisted unit, an axis of rotation
transverse to the axis of rotation of the intermediate storer
arrangement, grooves formed in the storage surface of said disc and
extending in the direction of said axis of rotation for at least
part of the altitude of said storage surface, and a tumbling
deflector ring having teeth extending therefrom and engaged in the
grooves of said storage surface for displacing the section of said
twisted unit stored on said storage surface.
2. Apparatus as claimed in claim 1, wherein said intermediate
storer means includes driving means coupled to said intermediate
storer for rotating said intermediate storer about its axis of
rotation in periodically different directions and coupled to each
of said take up reel and said pay out reel for rotating each of
said reels at a speed proportional to the speed of rotation of said
intermediate storer.
3. Apparatus as claimed in claim 2, wherein said driving means
rotates said intermediate storer at a substantially constant speed,
then decreases said speed uniformly when the time for changing the
direction of rotation approaches, then rotates said intermediate
storer at a substantially constant low speed for a short period of
time, and then decreases said speed uniformly to zero.
4. Apparatus as claimed in claim 3, wherein said driving means
maintains said intermediate storer at zero speed of rotation for a
short period of time.
Description
DESCRIPTION OF THE INVENTION
The present invention relates to apparatus for stranding a twisted
unit of a cable. More particularly, the invention relates to an
intermediate storer for apparatus for stranding a twisted unit of a
cable.
The present production of communication cables is concerned with
combining a plurality of stranding or twisting operations, which
heretofore have been undertaken separately, in a single working
operation in order to increase the efficiency and economy of
production. The twisting or stranding operation involves the
twisting or stranding of spiral or quad cables and modular bunching
or combining of the twisted cables. In order to accomplish a single
working operation, twisting devices are required which would enable
the stranding of the twisted units previously stranded from a
plurality of cable elements, in successive sections of length,
alternating between a left hand or S twist and a right hand or Z
twist. Stranding operations of this type, referred to as pendulum
stranding or SZ stranding, have the advantage of permitting the
elements to be twisted to be run off or removed from stationary
take up stands. Furthermore, further processing of a twisted unit
produced by SZ twisting of the cable elements may be squarely
effected during the same operation.
The devices previously utilized for SZ stranding generally utilize
longitudinal storers or intermediate storers which provide a double
function. The intermediate storers simultaneously function as take
up devices for the supplied incoming length section of the twisted
unit and as pay out devices for the removal of the outgoing length
section. The direction of twisting is thereby alternated at
intervals depending upon the length content of the intermediate
storer. An intermediate storer is described, for example, in U.S.
Pat. No. 3,169,360. The intermediate storer described in the
aforementioned patent comprises a disc having a groove for guiding
the twisted unit.
The principal object of the present invention is to provide new and
improved apparatus for stranding a twisted unit of a cable.
More particularly, an object of the present invention is to provide
apparatus for stranding a twisted unit of a cable in different
directions of stranding.
An object of the present invention is to provide a new and improved
intermediate storer for apparatus for stranding a twisted unit of a
cable.
An object of the present invention is to provide an intermediate
storer for apparatus for stranding a twisted unit of a cable, which
intermediate storer functions with efficiency, effectiveness and
reliability.
An object of the present invention is to provide an intermediate
storer for apparatus for stranding a twisted unit of a cable, which
intermediate storer is economical in production and operation.
An object of the present invention is to provide an intermediate
storer for apparatus for stranding a twisted unit of a cable, which
intermediate storer insures a reliable supply to and removal from
the intermediate storer of the twisted unit.
The present invention is based upon our recognition that in an
intermediate storer, which stores a twisted unit comprising a
plurality of adjacent turns, the take up turn of the twisted unit
is displaced a specific interval relative to the pay out turn of
said twisted unit. During the rotation of the intermediate storer
about its axis of rotation, which extends in the direction of the
twisted unit supplied to the intermediate storer, or parallel to
the twisted unit at a specific distance from said intermediate
storer, the take up portion of the cable elements and/or the pay
out portion of the twisted unit would undertake a rotary motion
about the axis of rotation. This would result in particular
difficulties during the supply of the cable elements or the take up
of the twisted unit to the intermediate storer, or during the
removal of the twisted unit from the intermediate storer.
The foregoing difficulties may be overcome, for example, by guiding
the cable elements or the twisted unit through a plurality of
deflection rollers in a manner whereby they may be supplied to the
intermediate storer in the axis of rotation and may be removed from
the intermediate storer in the axis of rotation. In accordance with
the present invention, however, the intermediate storer is of
considerably more simple construction and structure and imposes
considerably less stress or strain upon the cable elements. The
intermediate storer of the present invention insures a reliable
supply to and removal from the intermediate storer of the twisted
unit.
In accordance with the present invention, apparatus for stranding a
twisted unit of a cable in different directions of stranding
comprises a plurality of cable elements. A take up point forms a
twisted unit from the cable elements. An intermediate storer
arrangement is positioned between the take up point and a pay out
point and engages the twisted unit. The intermediate storer
arrangement rotates the twisted unit about an axis of rotation a
number of twists between the take up point and the pay out point
and provides a different direction of stranding of twisted unit for
individual section lengths. The intermediate storer arrangement
comprises an intermediate storer. A take up reel at the take up
point supplies the twisted unit to the intermediate storer in the
direction of the axis of rotation of the intermediate storer. A pay
out reel at the pay out point and on the axis of rotation of the
intermediate storer removes the twisted unit from the intermediate
storer in the direction of the axis of rotation.
The intermediate storer comprises a disc. It is particularly
expedient to provide the axis of rotation of the intermediate
storer through the center of gravity thereof, since this provides
the smoothest possible run for the rotating intermediate
storer.
The intermediate storer comprises a disc having a storage surface
for the twisted unit. Grooves are formed in the storage surface of
the disc and extend in the direction of the axis of revolution for
at least part of the altitude of the storage surface. A tumbling
deflector ring has teeth extending therefrom and engaged in the
grooves of the storage surface. The tumbling deflector ring
displaces the section of the twisted unit stored on the storage
surface. The deflector ring continually displaces the turns of the
twisted units stored on the storage surface of the intermediate
storer, so that subsequent turns may be taken up by said
intermediate storer without superposition on the turns already
stored.
The engagement of the deflector ring with the grooves in the
storage surface of the disc prevents the clamping of the twisted
unit between said deflector ring and said storage surface. This is
due to the fact that the twisted unit, stored on the storage
surface of the disc and displaced by the deflector ring, may
comprise, for example, a spiral quad stranded from very thin wires.
Since there must be a short distance between the deflector ring and
the storage surface of the disc in order to enable the deflector
ring to tumble on said disc, there is a possibility that during the
displacement of the twisted unit by the deflector ring, a stranded
element such as, for example, a wire from the spiral quad, may
become clamped between said deflector ring and said storage
surface. This may result in damage to the insulation of the wire.
This type of damage cannot occur in the intermediate storer of the
present invention.
A section of the twisted unit in which the cable elements are
twisted in the same direction is stored on the intermediate storer,
which is utilized for SZ twisting, and is subsequently removed from
said intermediate storer in a different twisting direction. Since
the reversal of the direction of rotation of the intermediate
storer is not sudden, but occurs within a specific period of time,
the number of twisting strokes produced per unit length of the
twisted unit is decreased to zero and is subsequently increased to
the predetermined number of revolutions for the specific direction
of rotation. This results in sections of the twisted unit which are
not sufficiently stranded and which may be readily twisted under
the force exerted upon the cable elements.
In accordance with the present invention, in order to eliminate the
foregoing difficulties involving undesirable twisting, the
intermediate storer arrangement includes a drive unit coupled to
the intermediate storer for rotating the intermediate storer about
its axis of rotation in periodically different directions and
coupled to each of the take up reel and the pay out reel for
rotating each of the reels at a speed proportional to the speed of
rotation of the intermediate storer. The speed of supply and the
speed of removal of the twisted unit to and from the intermediate
storer is thus proportional to the rotary speed of said
intermediate storer. The speed of supply and removal of the twisted
unit thus varies in proportion to the speed of rotation of the
intermediate storer. This insures that the twisting of a section of
length of the twisted unit, having the same twisting direction, is
constant along the entire section. The twisted unit is thus
sufficiently stranded relative to the reverse direction of
twisting, so that there is no need to provide additional devices
for preventing undesirable twisting of the twisted unit.
The variation in the direction of rotation of the intermediate
storer must occur at the exact instant at which a new section of
length of the twisted unit starts to pay out from said intermediate
storer. If there is a difference between these two instants of
time, the section of the twisted unit removed from the intermediate
storer during the difference period of time will be stressed with a
twist in an undesired direction, superimposed upon the existing
twist. This may produce sections of the twisted unit having a very
weak twist or no twist at all. Prior to the present invention, the
precise coincidence of both instants of time created problems
because the intermediate storer had to be decreased in speed to
zero, from a relatively high speed of rotation, at an exact instant
determined by the length of a section of the twisted unit having
the same direction of twisting.
In accordance with the present invention, the foregoing
difficulties are overcome by rotating the intermediate storer at a
substantially constant speed, then decreasing the speed uniformly
when the time for changing the direction of rotation approaches.
The intermediate storer is then rotated at a substantially constant
low speed for a short period of time and its speed is then
decreased uniformly to zero. The drive unit then maintains the
intermediate storer at zero speed of rotation for a short period of
time. This insures precise coincidence of the aforedescribed two
instants of time. A particular advantage of maintaining the
intermediate storer at zero speed of rotation for a short period of
time is that such operation results in a very smooth reversal of
the direction of rotation. This, in turn, results in very little
stress on the elements of the twisted unit and therefore enhances
the operation of the apparatus of the present invention.
In accordance with the present invention, apparatus for stranding a
twisted unit of a cable in different directions of stranding
comprises a plurality of groups of cable elements. Each of a
plurality of take up points forms a twisted unit from the cable
elements of a corresponding one of the groups of cable elements.
Each of a plurality of pay out points cooperates with a
corresponding one of the take up points. Each of a plurality of 106
out parallel-operating intermediate storer arrangements is
positioned between a corresponding cooperating take up point and
pay out point and engages a corresponding twisted unit. Each of the
intermediate storer arrangements rotates the corresponding twisted
unit about an axis of rotation a number of twists between the
corresponding take up point and the corresponding pay out point and
provides a different direction of stranding of the corresponding
twisted unit for individual section lengths. Each of the
intermediate storer arrangements comprises an intermediate storer.
A take up reel at the corresponding take up point supplies the
corresponding twisted unit to the intermediate storer in the
direction of the axis of rotation of the intermediate storer. A pay
out reel is provided at the corresponding pay out point and on the
axis of rotation of the intermediate storer for removing the
corresponding twisted unit from the intermediate storer in the
direction of the axis of rotation. An additional take up point
forms a resultant twisted unit from the twisted units of a
plurality of intermediate storer arrangements. An additional
intermediate storer arrangement operating in series with the
plurality of intermediate storer arrangements is positioned between
the additional take up point and an additional pay out point and
engages the resultant twisted unit.
The additional intermediate storer arrangement comprises an
additional intermediate storer. An additional take up reel at the
additional take up point supplies the resultant twisted unit to the
additional intermediate storer in the direction of the axis of
rotation of the additional intermediate storer. An additional pay
out reel at the additional pay out point and on the axis of
rotation of the additional intermediate storer removes the
resultant twisted unit from the additional intermediate storer in
the direction of the axis of rotation.
The intermediate storer arrangements and the additional
intermediate storer arrangement include a driving unit coupled to
each of the intermediate storers and to the additional intermediate
storer for rotating the intermediate storers and the additional
intermediate storer about their axes of rotation in periodically
different directions. The drive unit is coupled to each of the take
up reels and the additional takeup reel and to each of the pay out
reels and the additional pay out reel for rotating each of the
reels at a speed proportional to the speed of rotation of the
intermediate storers and the additional intermediate storer.
In accordance with the present invention, a method of stranding a
twisted unit of a cable in different directions of stranding
comprises forming a twisted unit from the cable elements at a take
up point. The twisted unit is engaged between the take up point and
a pay out point. The twisted unit is rotated about an axis of
rotation a number of twists between the take up point and the pay
out point and a different direction of stranding of the twisted
unit is provided for individual section lengths. The twisted unit
is supplied for engagement and rotation in the direction of the
axis of rotation. The twisted unit is removed in the direction of
the axis of rotation after rotation.
In order that the present invention may be readily carried into
effect, it will now be described with reference to the accompanying
drawings, wherein;
FIG. 1 is a schematic diagram of an embodiment of the apparatus of
the present invention;
FIG. 2 is a top view of an embodiment of the intermediate storer
arrangement of the present invention;
FIG. 3 is a radial sectional view of part of an embodiment of the
intermediate storer of the present invention;
FIG. 4 is a graphical presentation of the speed of rotation of the
intermediate storer of the present invention;
FIG. 5 is a graphical presentation of the speed of supply to and
removal from the intermediate storer of the twisted cable;
FIG. 6 is a schematic diagram of a modification of the apparatus of
FIG. 1 of the present invention;
FIG. 7 is a diametrical sectional view of the intermediate storer
of FIG. 3; and
FIG. 8 is a schematic diagram of an embodiment of the drive unit
30' of the apparatus of FIG. 6.
In the figures, the same components are identified by the same
reference numerals.
The apparatus of FIG. 1 twists a plurality of stranding or cable
elements into a twisted unit, the twisting direction of which
changes for each section of length. Thus, for example, in FIG. 1
four cable elements or wires are twisted into a spiral quad. In
FIG. 1, the cable elements 1 are supplied from storage drums 2 to a
nipple 3. The nipple 3 combines the cable elements 1 and supplies
them to an intermediate storer arrangement 4. The twisted unit
removed from the intermediate storer arrangement 4 is then wound on
the drum 5.
The cable elements from the nipple 3 are supplied to a take up reel
6 of the intermediate storer arrangement 4. The take up reel 6
supplies the twisted unit formed by the take up reel 6 to the
intermediate storer 8 of the intermediate storer arrangement 4. The
intermediate storer 8 has a tumbling deflector ring 7 mounted
thereon. The twisted unit is removed from the intermediate storer 8
to a pay out reel 9. The intermediate storer 8 may be rotated in a
counter-clockwise direction, as indicated by the single arrow,
about an axis C-D, passing through the center M of the intermediate
storer 8. The intermediate storer 8 is driven about the axis C-D by
the twisted unit wound on its storage surface (FIG. 3).
The intermediate storer arrangement 4, which comprises the take up
reel 6, the intermediate storer 8 and the pay out reel 9, is
rotatable about an axis of rotation A-B, in both clockwise and
counter-clockwise directions, as indicated by the pair of arrows in
FIG. 1. During the stranding of the cable elements 1 to form the
twisted unit 10, said elements are twisted in a specific direction
while they are being taken up by the take up reel 6 at a point a.
The intermediate storer arrangement 4 rotates about its axis of
rotation A-B and periodically changes its direction of rotation.
The twisted unit is then supplied by the take up reel 6 to the
intermediate storer 8 and is wound a plurality of times on said
intermediate storer in accordance with the desired position of a
section of length of said twisted unit. Each section of length of
the twisted unit has the same direction of twist or twist
direction.
The number of windings of the twisted unit on the intermediate
storer 8 varies in accordance with the capacity of the intermediate
storer arrangement 4, which depends upon the length of a section of
said twisted unit, twisted in the same direction. When the full
capacity of the intermediate storer arrangement 4 is utilized by a
length section of the twisted unit, twisted in the same direction,
the direction of rotation of said intermediate storer arrangement
is reversed. As a result of the reversal of the direction of
rotation, the twisted unit is removed to a point b, where the pay
out reel 9 is positioned, with an additional twist in the same
direction, during the run off of said twisted unit from the
intermediate storer 8. The pay out reel 9 superimposes the
additional twist on the initial twist.
Simultaneously with the removal of the twisted unit to the pay out
reel 9, a new length section of twisted unit is supplied to the
intermediate storer arrangement 4 and is stranded with a twist in
the opposite direction. When the full capacity of the intermediate
storer arrangement 4 is utilized by the new length section, the
direction of rotation of said intermediate storer arrangement is
again reversed, so that said new length section is also provided
with an additional twist in the same direction, during its removal
from the intermediate storer 8. The additional twist is
superimposed upon the next-preceding twist. In this manner, the
twisted or cable elements 1 are alternately provided in sections of
length with two opposite twists of equal magnitude.
In order to prevent the necessity for reversing the direction of
rotation of the intermediate storer arrangement 4, said
intermediate storer arrangement must have a maximum storage
capacity. The maximum storage capacity is provided in the apparatus
of the present invention by winding the twisted unit on the storage
surface of the intermediate storer disc 8 in a plurality of
adjacent turns (FIGS. 2 and 3). The intermediate storer 8 is in the
configuration of a disc of, for example, I cross sectional
configuration (FIG. 3). The storage surface of the disc is the
cylindrical peripheral outer surface.
The turn of the twisted unit supplied to the intermediate storer 8
and the turn of said twisted unit removed from said intermediate
storer are mutually displaced relative to a plane perpendicular to
the axis C-D (FIG. 2). Thus, rotation of the intermediate storer 8
about the axis of rotation A-B perpendicular to the axis C-D would
produce a rotary movement of the supplied portion of the twisted
unit, including the take up reel 6, and the removed portion of said
twisted unit, including the pay out reel 9, about said axis of
rotation. This would result in supplying the twisted elements or
cable elements and in taking up or supplying and removing or
running off the twisted unit to or from the intermediate storer
8.
As shown in FIG. 2, the axis of rotation A-B of the intermediate
storer arrangement 4 is so selected that the take up reel 6 is
positioned at the take up point a and the pay out reel 9 is
positioned at the pay out point b on said axis of rotation. The
twisted unit is supplied by the take up reel 6 to the intermediate
storer 8 in the direction of the axis of rotation A-B and said
twisted unit is removed from said intermediate storer to the pay
out reel 9 in said direction. This results in a satisfactory and
protected supply system for the cable elements 1 to the
intermediate storer arrangement 4. The dimensions of the
intermediate storer 8 are such that its axis C-D and its axis of
rotation A-B are at an angle of less than 90.degree. with each
other (FIG. 2).
The section of the twisted or stranded unit taken up by the
intermediate storer or storage disc 8, must be constantly shifted
on the storage surface 11 of said intermediate storer, which
surface serves as a storage area, in order to make room for the new
sections of the twisted unit which are being taken up. To
accomplish this, the intermediate storer or storage disc 8 is
provided with the deflection ring 7, which, as shown in FIGS. 3 and
7, is so positioned that is effects a tumbling movement, relative
to the storage disc. The tumbling movement is produced through
several sliding blocks 26, as shown in FIG. 7, equiangularly
distributed along the periphery, which are firmly affixed to a
stationary star-shaped carrier disc 25 and which engage the
U-shaped deflection ring 7 in the manner described in our copending
patent application Ser. No. F-4167. The parts of the sliding blocks
which engage the U-shaped deflection ring 7 are mutually displaced
in axial direction of the intermediate storer 8, so that when said
intermediate storer rotates, the deflection ring 7, taken along by
said intermediate storer, carries out a back and forth movement, on
the storage surface of said intermediate storer.
In order to prevent the twisted elements or cable elements 1 of the
twisted unit 10 such as, for example, the wires of a spiral quad,
from becoming clamped in the space between the deflector ring 7 and
the storage surface 11 of the intermediate storer 8, which clamping
could damage the insulation of said wires, said storage surface 11
has a plurality of grooves 12 formed therein. The grooves 12 extend
in directions parallel to the axis C-D of the intermediate storer 8
and are equidistantly spaced around the storage surface 11. Each of
the grooves 12 extends for at least part of the altitude of the
storage surface 11. The deflector ring 7 has a plurality of teeth
13 extending therefrom. The teeth 13 of the deflector ring 7 are
engaged in the grooves 12, which grip said teeth.
The deflector ring 7 is thus affixed to the storage surface 11 of
the intermediate storage 8 in the manner of a comb, in the area
wherein the twisted unit is displaced or shifted by said deflector
ring. The stranded or cable elements of the twisted unit 10 are
thus prevented from being clamped between the deflector ring 7 and
the storage surface 11. The distance between next-adjacent grooves
12 is preferably equal to the width of a groove. This provides a
good bearing for the twisted unit on the storage surface 11 and a
good bearing of said twisted unit against the deflector ring.
A stage, step or inclination 14 is provided in the storage surface
11 of the intermediate storer 8, as shown in FIG. 3. The turns of
the twisted unit, taken up by the intermediate storer 8, are
displaced or shifted by the deflector ring 7 across the inclination
14. As a result, the force with which the twisted unit is first
wound upon the storage surface 11 is decreased during the
displacement of the respective turn of the twisted unit across the
inclination 14, until said twisted unit only bears loosely on the
intermediate storer 8. This considerably decreases the forces
required for displacing or shifting the twisted unit. This is
particularly important for a gentle handling or treatment of the
twisted elements during the movement of the intermediate storer
arrangement, since the rotation of the intermediate storer 8, and
thus also the displacement of the twisted unit, is effected by
forces exerted upon the twisted elements or cable elements by a
removable device, not shown in the figures.
The storage surface 11 of the intermediate storer 8 may be of
conical configuration, rather than having the inclination 14 formed
therein. A conical storage surface enables a gradual decrease of
the pulling force in the twisted elements when the twisted unit is
displaced on said storage surface.
FIG. 4 illustrates the rotary speed, in revolutions per minute, of
the intermediate storer arrangement 4. In FIG. 4, the abscissa
represents time and the ordinate represents the speed n of the
intermediate storer arrangement 4. In accordance with the present
invention, the speed n of the intermediate storer arrangement is
always proportional to the supply and removal or take off speed v
of the twisted or cable elements 1, even when such speed is
varied.
As shown in FIG. 4, the speed n fluctuates, within a period L,
between two magnitudes +n.sub.1 and -n.sub.1. The transition from
one direction of rotation (+ to - or - to +) to the other occurs as
follows. A drive unit 30, as shown in FIG. 1, may comprise any
suitable driving arrangement for producing the desired driving
operation. The drive unit 30 is coupled to each of the take up reel
6, the intermediate storer 8 and the pay out reel 9.
The drive of the intermediate storer arrangement 4, including the
take up reel 6, the intermediate storer 8 and the pay out reel 9,
is discontinued at the instant t.sub.1 provided by a counter device
which registers the number of rotations of said intermediate storer
arrangement. The speed n is first uniformly decreased due to
friction forces, until the instant t.sub.2. At the instant t.sub.2,
the speed n has a small magnitude n.sub.2, controlled by a
speedometer or speed indicator. The drive is subsequently
reinstituted for a brief period of time, at, for example, a
decreased torque. The intermediate storer 8 is permitted to rotate
for a short period of time at a speed having a magnitude n.sub.2,
as shown in FIG. 4. The drive provided by the drive unit 30 is then
discontinued at the instant t.sub.3, which is determined by a
counter device, and the intermediate storer arrangement 4 decreases
uniformly in speed to zero. The speed of the intermediate storer
arrangement is zero at the instant T.sub.1.
After a brief period of standstill, at zero speed, the intermediate
storer arrangement 4 begins to rotate in the opposite or reverse
direction. The speed n is uniformly accelerated until it reaches
its magnitude -n.sub.1. During the continuation of the operation,
the variation in the direction of rotation occurs at the
commencement of each new period L, at the time instants T.sub.2,
T.sub.3, and so on. The period L thereby corresponds to the period
in which a length of the twisted elements or a twisted unit
corresponding to the storage capacity of the intermediate storer
arrangement 4 is supplied to said intermediate storer arrangement.
Since the supply and removal speed v of the twisted elements is
proportional to the speed n of the intermediate storer arrangement
4, the period L corresponds in the same manner to the period during
which said intermediate storer provides a constant number of
rotations for a length section having the same direction of
twisting or stranding.
The graphical indication or curve of the speed of rotation of the
intermediate storer arrangement 4 initially decreases uniformly in
magnitude, is then constant for a brief period, then decreases
uniformly again in magnitude for a very brief period, and is then
at zero for a very brief period, as hereinbefore described, and
permits very exact adherence to the twisting period L. This is
necessary to enable the variation in the direction of rotation of
the intermediate storer to occur at the exact instant at which a
new section of length of the twisted unit commences to run off from
said intermediate storer. If there is a difference between these
two instants, the section of twisted unit which is run off from the
intermediate storer 8 during this period is stressed with a twist
in an undesired direction. The undesired twist is superimposed upon
the twist in the twisted unit. This produces a section of length of
twisted unit in which the twist is very weak or there is no twist
at all.
FIG. 5 illustrates the speed v at which the twisted unit is
supplied to and removed from the intermediate storer arrangement 4.
In FIG. 5, the abscissa represents the time t and the ordinate
represents the speed v. In accordance with the present invention,
the speed v of the supply to and the removal from the intermediate
storer arrangement of the twisted unit or twisted elements is
always proportional to the speed of rotation n of said intermediate
storer arrangement. This is also true when the speed of rotation of
the intermediate storer arrangement varies. This relation between
the speed v and the speed n is apparent from a comparison of FIGS.
4 and 5. The proportionality of both magnitudes of speed v and n
results in the provision of the twisting of a length section of the
twisted unit having the same direction over the entire length
section. The twisted unit is thus sufficiently stranded relative to
the twisting direction and the reverse twisting direction, so that
there is no need for additional devices for preventing twisting in
an undesired direction.
In a modification of the embodiment of FIG. 1 of the present
invention, apparatus for stranding cable elements, particularly
communication cables, comprises a plurality of systems of the type
shown in FIG. 1. The systems operate in parallel with each other
and each corresponds to the embodiment of FIG. 1. An additional
intermediate storer arrangement operates in series with the
plurality of intermediate storer arrangements to twist the
resultant twisted unit supplied by said plurality of intermediate
storer arrangements. It is thus possible to combine two stranding
or twisting processes in the same working operation. The stranding
or twisting apparatus which is connected in series with the
plurality of intermediate storer arrangements, may, in accordance
with the present invention comprise a rotating additional take up
reel for stranding the resultant twisted unit from said
intermediate storer arrangements in a stranding nipple. An
additional intermediate storer and an additional pay out reel are
also provided and function together with the additional take up
reel as the additional intermediate storer.
It is especially preferable that the supply to and removal from the
additional intermediate storer arrangement of the resultant twisted
unit have the same speed relation to the speed of rotation of the
intermediate storer arrangements as in the embodiment of FIG.
1.
FIG. 6 illustrates the modification of the embodiment of FIG. 1,
wherein a plurality of intermediate storer arrangements 4 are
provided in a manner whereby they operate in parallel. An
additional intermediate storer arrangement 22 is provided in a
manner whereby it operates in series with the parallel-connected
intermediate storer arrangements 4 to strand or twist the resultant
twisted unit provided by said parallel-connected intermediate
storer arrangements.
In FIG. 6, five intermediate storer arrangements 4 are illustrated.
In each of the apparatus for the intermediate storer arrangements
4, communication cable elements or wires 1 are supplied by a
storage drum 2 to the corresponding immediate storer arrangement.
Each of the intermediate storer arrangements 4 produces a spiral
quad 10 simultaneously with the others. The twisted units or spiral
quads 10 are combined to a resultant twisted unit by the additional
take up reel 31. The resultant twisted unit is then twisted into
modular bunches or units 23 by the additional intermediate storer
arrangement 22. The speed of removal of the twisted, twisted unit
23 from the additional intermediate storer arrangement 22 is
determined by the speed of rotation of a take off disc 15.
Each of the intermediate storer arrangements 4 periodically
alternates its direction of rotation and therefore its direction of
twisting. When they are combined to form the resultant twisted
unit, the individual twisted units 10 are stranded together in a
specific direction. Preferably, the speed of rotation and, if
necessary, the direction of rotation, of the intermediate storer
arrangements 4 are made to vary. This provides electrical
decoupling of the twisted unit or spiral quad 10 which is a
component of the twisted, twisted unit or modular bunch 23. When an
intermediate storer arrangement 4 is filled to capacity with a
section of length of twisted unit having the same direction of
twisting, the direction of rotation of such intermediate storer
arrangement is reversed. The intermediate storer arrangements 4
rotate in the same direction, so that they are reversed in
direction at the same time.
As a result of the change in direction of the rotation of the
intermediate storer arrangements 4, the twisted units 10 are
provided with an additional twist, in the same direction, which is
superimposed upon the initial twist provided prior thereto during
the supply of the twisted unit to the intermediate storer
arrangement. Simultaneously, new sections of twisted units are
supplied to the intermediate storer arrangements 4 and are twisted
in the opposite direction. When the intermediate storer
arrangements 4 are filled to capacity with the new sections of
length of twisted units, the direction of rotation of said
intermediate storer arrangements is again reversed, so that such
new sections are also provided, during their run off from the
intermediate storer arrangements, with an additional twist, in the
same direction, which is superimposed upon the preceding twist. In
this manner the twisted units or spiral quads are alternately
provided, in length sections, with two opposite twists of equal
magnitude.
After the twisted unit 10 is provided by an intermediate storer
arrangement 4, said twisted unit is supplied to a corresponding
longitudinal or length storer 16. Each length storer 16 comprises
two deflection rollers 17 and 18 positioned in sequence. The
individual twisted units are wound on the deflection rollers 17 and
18 at different rates. Therefore, each of the twisted units 10 has
a different path length in its extension from the corresponding
intermediate storer arrangement 4 to a guide nipple 19. This
results in the points of the individual twisted unit at which the
direction of twist alternates, being non-adjacent following the
twisting of the resultant twisted unit into the twisted, twisted
unit 23. These points are mutually displaced.
After the five twisted units 10 are provided by the corresponding
length storers 16, they are supplied, via the guide nipple 19 which
combines them into the resultant twisted unit, to the additional
intermediate storer arrangement 22. The additional intermediate
storer arrangement 22 is the same as each of the intermediate
storer arrangements 4 and comprises the additional take up reel 31,
an additional intermediate storer 32 and the additional pay out
reel 33. The additional intermediate storer arrangement rotates at
a speed in accordance with the twisting which is customary in
producing stranding or twisted, twisted units or modular bunches.
The additional intermediate storer arrangement 22 operates in the
same manner as each of the intermediate storer arrangements 4. The
twisted, twisted unit 23 is thus alternatively provided in sections
of length with twists of the same magnitude in opposite
directions.
The twisted, twisted unit 23 is supplied to a central spinner 20
which functions to provide the SZ twisted, twisted unit with the
helical marker. The twisted, twisted unit 23 is then wound on a
take off disc 15 and a drum 21. The take off disc 15 rotates in
clockwise direction, as indicated by the arrow.
The speed of rotation of the take off disc 15 determines an equally
high supply and removal speed for the twisted units relative to the
intermediate storer arrangements 4. The supply and removal speeds
are determined in a manner whereby they are proportional to the
speed of rotation of the intermediate storer arrangements 4. Thus,
every variation in the speed of rotation of the intermediate storer
arrangements 4 and the additional storer arrangement 22 occurs at
the same instant. Furthermore, the speed of rotation of each
intermediate storer arrangement 4 and the additional intermediate
storer arrangement 22 has a constant relationship to the speed of
rotation of every other intermediate storer arrangement at any
instant. This enables each of the intermediate storer arrangements
4, the additional intermediate storer arrangement 22 and the take
off disc 15 to be driven by a drive unit 30', essentially similar
to the drive unit 30 of FIG. 1. The drive unit 30' may comprise any
suitable driving arrangement, which may operate from a single drive
source, for driving the take up reels, pay out reels and
intermediate storers of the intermediate storer arrangements at the
desired speeds and for rotating the take off disc 15 at the desired
speed.
In actual operation of the apparatus of FIG. 6, we found it
expedient to select the length of a section of the twisted unit,
having the same direction of twist, as 20 meters. Each of the
intermediate storer arrangements 4 was rotated at an average speed
of 500 rpm. The additional intermediate storer arrangement 22 was
rotated at approximately 170 rpm. The twisted, twisted unit was
produced at the rate of approximately 50 meters per minute.
FIG. 8 is a drive unit which may be utilized as the drive unit 30'
of FIG. 6 and which may serve as the drive unit 30 of FIG. 1. With
the exception of the rotation of the take-up drum 21, all
rotational movements of the SZ twisting device, shown in FIG. 6,
are controlled by a motor 35. The motor 35 of FIG. 8 controls the
rotational movements of the intermediate storers 4, the additional
intermediate storer arrangement 22, the central spinner 20 and the
take off disc 15.
As shown in FIG. 8, the motor 35 drives the shaft 39, via a gear
comprising toothed wheels 36, 37 and 38. A belt pulley 40 is
affixed to the right end of the shaft 39. The belt pulley 40 drives
a belt pulley 42, via a belt 41. The belt pulley 42 is mechanically
coupled to the shaft of the take off disc 15 (FIG. 6).
A belt pulley 43 is also affixed to the shaft 39 and drives a belt
pulley 45 via a belt 44. The belt pulley 45 is mechanically coupled
to and drives or rotates the central spinner 20 (FIG. 6).
Switchover apparatus 46 is mounted on the left side of the shaft
39. The switchover apparatus 46 which alternately changes the
direction of rotation, by sections, of a belt pulley 47 affixed to
the shaft 39 at its left end, the belt pulley 47 drives a belt
pulley 49 via a belt 48. The belt pulley 49 is affixed to, and
drives, a shaft 50. Two belt pulleys 51 and 53 are affixed to the
shaft 50 and are therefore driven by the belt pulley 49. The
intermediate storers 4 (FIG. 6) are driven by the belt pulley 51
via a belt 52. The additional intermediate storer arrangement 22
(FIG. 6) is driven by the belt pulley 53 via a belt 54.
The switchover apparatus 46 comprises a pair of couplings 55 and
56, of which one is engaged at any time. When the coupling 55 is
engaged, the belt pulley 47 is rotated in the direction in which
the shaft 39 is driven by the motor 35. When the coupling 56 is
engaged, the direction of rotation of the belt pulley 47 is
reversed, via a gear wheel 57. The switchover or reversal of the
couplings 55 and 56 is effected at times T.sub.1, T.sub.2, T.sub.3,
indicated in FIG. 4.
The speed n.sub.2 of the motor 35, indicated in FIG. 4, is
controlled by a control circuit comprising a speed controller 58, a
relay switch 59 and a variable resistor 60. When the speed of the
intermediate storer 4, or the additional intermediate storer
arrangement 22, is decreased, in accordance with FIG. 4, from
+n.sub.1 or from -n.sub.1, the speed of the motor 35 is supervised
by the speed controller 58. When the speed +n.sub.2 or -n.sub.2 is
reached the speed controller 58 responds and connects the variable
resistor 60 into the current circuit of the motor 35, via the relay
switch 59. The motor 35 then rotates at the speed determined by the
variable resistor 60, until it is switched off by counting
apparatus not shown which counts the number of revolutions of the
intermediate storers 4, or the additional intermediate storer
arrangement 22. The switch-off occurs at t.sub.3 and the motor 35
comes to a standstill at T.sub.1.
While the invention has been described by means of specific
examples and in specific embodiments, we do not wish to be limited
thereto, for obvious modifications will occur to those skilled in
the art without departing from the spirit and scope of the
invention.
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