Method and apparatus for making elongated flat wire coils

A wire winding blade extends through spiral outfeed guide members and receives spring-like unannealed wire from a source drawn by rotation of the winding blade; the wire from the source first passes through tensioning means then over an infeed guide pulley which guides it into a linear guide member having a bore slightly in excess of the wire diameter from which the wire passes over a small diameter idler roller sheave which imparts a back bend to the wire which is then fed into the slot of the spiral wire guide means where it is bent in a reverse manner about the winding blade.

BACKGROUND OF THE INVENTION 
Woven wire conveyor belts have been used for many years in the glass and 
other industries for conveying items through hot and/or caustic 
environments. Such woven wire conveyor belts are formed of a plurality of 
interlocked elongated flat spiral annealed steel wire members consisting 
of a large number of spirals with each spiral comprising spaced 
essentially linear top and bottom leg portions connected by arcuately 
curved end portions. The arcuately curved end portions of each elongated 
flat spiral member are interleaved with the adjacent arcuately curved end 
portions of the next adjacent elongated flat spiral member and a crimped 
rod extends through the interleaved portions of the spiral members to 
retain the elongated flat spiral wire members in position and permit 
pivotal movement of each elongated flat spiral member with respect to the 
next adjacent elongated flat spiral member. 
It has been conventional practice to form woven conveyor belts of the 
aforementioned type of annealed steel alloy or other similar relatively 
pliable wire having a maximum tensile strength in the range of 65,000 to 
100,000 pounds per square inch. Each of the flat spiral members is formed 
by feeding the wire to a flat rotating winding blade supported for 
rotation on one end and having an opposite end extending through a spiral 
outfeed guide having a spiral slot surrounding the rotating winding blade. 
The wire is fed in through the slot of the spiral onto the winding blade. 
Rotation of the winding blade causes the wire to be wound onto the surface 
of the winding blade in a configuration following the configuration of the 
spiral slot of the flat outfeed spiral member so that an elongated flat 
spiral of wire is formed and moved outwardly to the unsupported end of the 
rotating winding blade. 
Since the wire used in forming the flat spiral members is subject to a 
substantial amount of bending and tension beyond its elastic limit as it 
is wound about the rotary winding blade, it is consequently much less 
difficult to form the flat spiral members of relatively soft wire due to 
the ease with which such wire can be wound in the necessary spiral 
formation. It has consequently been the practice in the industry to use 
relatively soft annealed steel for forming the vast majority of spiral 
wire members used in conveyor belts. However, annealed wire, which is 
formed by taking as-drawn wire from the drawing mill, heating same to 
annealling temperature or higher and then slowly cooling the wire to 
provide a relatively soft wire, has less tensile strength than the tensile 
strength of the as-drawn wire from which it is formed notwithstanding the 
fact that the as-drawn wire and the annealed wire are of identical 
chemical composition. In addition, the annealling process obviously adds 
10% to 15% to the cost of the wire over and above the cost of as-drawn 
wire and belts formed of the annealed wire are relatively heavy due to the 
fact that they must be formed of wire of sufficient diameter to provide 
the required tensile strength for a given conveyor belt installation. 
Moreover, the heaviness and mass of the presently used conveyor belts 
formed of annealed steel results in greater power consumption for driving 
the belts and greater heat absorption than would be the case if the 
lighter weight materials were employed. Similarly, many installations such 
as those in the glass industry employ woven conveyor belt conveyors which 
move through heated areas such as furnaces or lehrs and absorb a 
substantial amount of heat. Subsequent movement from the heated areas to 
areas external of the heated areas results in radiation and convection 
loss of absorbed heat to the surrounding area. Such heat loss is obviously 
undesirable and is becoming all the more critical in view of the ever 
increasing cost of fuel. By enabling the use of smaller wire, the present 
invention lowers the heat loss since there is less thermal storage 
capacity in the conveyor. 
Previous attempts to form elongated flat spiral wire members of as-drawn 
steel or other similar spring-like wire have not been successful due to 
the fact that existing wire winding devices and processes for forming the 
elongated flat spiral members have been incapable of winding spring-like 
metal into uniform elongated spiral wire members having the uniformity of 
shape necessary for use in forming woven conveyor belts. The foregoing is 
true due to the fact that the spiral wire members formed of as-drawn or 
similar spring-like steel or the like have varied dimensionally in terms 
of pitch between adjacent spirals and have had internal stresses creating 
an irregular axial twisting of the spiral members along their lengths so 
that the spiral members cannot be connected together to form a 
satisfactory conveyor belt. 
Therefore, it is the primary object of this invention to provide a new and 
improved means and method of forming woven conveyor belts of lighter 
weight and/or higher strength materials than has been heretofore possible. 
Another object of the invention is the provision of a new and improved 
apparatus and method for forming flattened elongated flat spiral wire 
members of lightweight high strength material. 
Still another object of the invention is the provision of a new and 
improved apparatus and method for forming elongated flat spiral wire 
members of spring-like as-drawn steel alloy having a tensile strength in 
excess of 100,000 to 150,000 pounds per square inch. 
Achievement of the objects of this invention is enabled by the preferred 
embodiment of the subject invention by the provision of unique controlled 
wire feeding, guiding and bending means for feeding spring-like wire to a 
conventional forming station consisting of a rotating winding blade 
extending through a flat spiral outfeed worm member. In the preferred 
embodiment, unannealed as-drawn steel alloy wire is fed through an 
elongated linear guide means in which a circular bore is provided with the 
circular bore being of slightly greater diameter than the diameter of the 
particular wire being employed so that the wire is fixedly guided along a 
linear path. The wire leaves the downstream end of the circular bore and 
passes immediately over bending means consisting of a small diameter 
roller member about which the wire is bent beyond its elastic limit so as 
to impart a set bend in the wire. The aforementioned roller means is 
positioned immediately upstream of the location in a conventional forming 
station at which the wire extends into the spiral groove of the relatively 
flat outfeed spiral member and is wound about the winding blade. Winding 
movement of the wire about the blade results in the wire being bent in the 
exact opposite direction from the set bend so that the wire is closely 
configured to the surface of the winding blade. 
The basic difference of the invention over the prior art approaches is in 
the provision of the guide means for completely stabilizing the feed of 
the wire practically up to the exact point of winding as opposed to the 
prior systems in which the internal stresses in the wire have been the 
cause of transverse shift in or whipping movement of the wire as it is fed 
onto the winding blade. Consequently, variations in internal stress occur 
at different locations in the finished spiral member to cause resultant 
undesirable bending and twisting of the spiral. In the present invention, 
the wire is guided and stabilized along a restricted linear path and then 
fed immediately over the back bend roller which bends the wire in a 
vertical plane which restrains the wire from transverse movement so as to 
prevent whipping of the wire member as has previously occurred with prior 
known systems. Moreover, the wire as it leaves the back bend roller member 
immediately engages one side of the groove in the spiral worm so that the 
wire feed is totally controlled up to the point that the wire is wrapped 
about the winding blade.

The preferred embodiment for practice of the invention is illustrated in 
the drawings and includes a frame 18 supporting a conventional wire 
bending and forming station 20 in which a rotating winding blade 22 
extends through spiral outfeed guide members 24 clamped in adjusted 
position by conventional support members 25 on frame 18. Each of the 
spiral outfeed guide members defines a spiral slot 26. It will be noted 
that the rotary winding blade 22 is connected by a clevis connector 27 to 
the output shaft 28 of a power source in housing 29 which imparts rotation 
to the blade member in the direction of arrows R in FIGS. 1 and 3. 
A supply of unannealed as-drawn high strength steel alloy wire 30 sold 
under the trademark "MAYARI R" by Bethlehem Steel Company of Bethlehem, 
Pa., having a maximum carbon content of 0.12%, a manganese range of 0.50% 
to 1.0%, a maximum phosphorous content of 0.12%, a maximum sulphur content 
of 0.05%, a silicon content in the range of 0.20 to 0.90%, a maximum 
copper content of 0.50%, a chromium content of 0.40 to 1.00%, a maximum 
nickel content of 1.00% and a maximum zirconium content of 0.10% is 
provided in a conventional manner. Wire 30 is fed inwardly through 
tensioning means 32 over an infeed guide pulley 34 to a linear guide means 
36 having a bore 38 extending along its length and of a diameter slightly 
greater than the diameter of the wire. Linear guide means 36 stabilizes 
the feed of the wire and prevents vibrations of the type that would 
normally occur in long flights of unsupported wire sections with the wire 
leaving the linear guide means 36 and immediately passing under a back 
bend idler roller sheave means 40 positioned closely adjacent the linear 
guide means. Back bend roller sheave means 40 is of a relatively small 
diameter and the wire travels in a peripheral groove 42 in the roller 
sheave and is bent beyond its elastic limit so that a set bend is imparted 
to the wire which is then fed immediately into the spiral slot 26 of the 
spiral guide 24 and is wrapped around the rotating winding blade 22 to 
conform to the cross-sectional shape of the winding blade as shown in FIG. 
4. The wrapping of the wire around the winding blade 22 results in a 
second bending of the wire in a direction exactly opposite the set bend 
imparted to the wire by the back bend roller 40. Continued rotation of the 
winding blade results in eventual movement of the elongated flat spiral 
wire member formed in the winding station outwardly of the winding and 
bending station as shown in FIG. 3. 
The winding blade 22 serves to draw the wire through tensioning means 32, 
over infeed guide pulley 34, through the bore 38 of linear guide 36, over 
the roller 40 and into the spiral slot 26 of the spiral outfeed guides 24. 
It will be appreciated that the wire extending from the tensioning means 
32 to the winding blade 22 is in substantial tension in accordance with 
the degree of adjustment of tensioning means 32. The flat spiral wire 
member 40 emerging from the leftmost spiral guide 24 is formed of a series 
of spaced parallel essentially linear top and bottom leg portions 42 
connected by curved end portions 44. A woven conveyor belt is provided 
from the flat spiral wire members by provision of undulating connector 
rods 48 extending through the interleaved end portions 44 to provide a 
conveyor belt construction as shown in FIG. 2. 
The inventive apparatus enables the formation of uniform flat spiral wire 
members of substantial dimensional uniformity which was previously 
achievable only with the use of soft annealed wire. Consequently, the 
elongated flat spiral members can be fabricated into woven conveyors with 
a minimum of difficulty. 
Previous attempts to form conveyor belts of unannealed wire resulted in 
flat spiral wire members having internal stresses and strains which 
resulted in dimensional variations in pitch of spirals and twist which 
prevented the wire members from being interleaved and woven together to 
form a conveyor of the type illustrated in FIG. 2. Consequently, it will 
be appreciated that the subject invention represents a distinct advance in 
the art fully deserving of patent protection. 
Conveyor belts formed of unannealed steel by the inventive apparatus and 
method are of particularly great utility when used as conveyors in the 
glass industry for conveying wire through lehrs and the like in which the 
temperatures do not exceed the annealling temperature of the wire. 
Consequently, the wire can be of smaller diameter than is required with 
annealed wire with the ability to use unannealed as-drawn wire resulting 
in substantial savings in material costs. Stretch comparison tests in 
which a woven conveyor belt formed of annealed MARARI R alloy as discussed 
on page 7 versus a woven conveyor belt formed of non-annealed as-drawn 
wire of the same composition reveals that the latter belt had one third 
less elongation under the same load than the annealed belt. 
It should also be appreciated that the inventive method and apparatus is 
not limited to the use of the "MARARI R" alloy which is given as an 
example of a usable alloy. In fact, the invention will permit the 
formation of elongated spiral wire members of a wide variety of other 
spring-like metals such as medium and high carbon steels of a tensile 
strength higher than heretofore possible to use. The invention can also be 
used for forming elongated spiral wire members of other hard alloys having 
a chromium content of up to 3%, for example. 
Actual tests have shown that by use of the afore-described devices, wire 
belts have been made of sufficiently high tensile strength to enable 
weight reduction of 30% to 50%. When used as conveyors in lehrs, these 
weight reductions provide heat savings in the range of 6,000,000 to 
12,000,000 BTU's per day per lehr. There are perhaps 5,000 lehrs in 
operation in the U.S. today. 
While modifications of the illustrated preferred embodiment will 
undoubtedly occur to those of skill in the art, it should be understood 
that the spirit and scope of the invention is to be limited solely by the 
appended claims.