Abstract:
A double-draft continuous wire drawing and collection machine having first and second reduction dies for drawing wire in succession. A rotary advancing block driven by a variable-speed first motor draws wire rod through the first reduction die, and a rotary flyer mechanism driven by a second motor draws wire through the second reduction die as it coils wire on a stationary block. A tension control arm and rheostat regulate the speed of the first motor based on wire tension differentials detected between the rotary advancing block and the second reduction die, in order to maintain constant wire tension in that wire segment.

Description:
BACKGROUND OF THE INVENTION 
     The field of the invention generally pertains to wire drawing and collection machines. The invention relates more particularly to a double-draft wire drawing and collection machine with tension-sensitive speed control. 
     Various types of wire drawing machines have been developed to mass produce large quantities of wire in a wide variety of gauges. In particular, continuous wire drawing machines have greatly improved wire production by incorporating consecutively arranged multiple reduction dies. This increases the number of passes or drafts experienced by wire rod, and consequently enables greater wire gauge reductions. 
     For example, in U.S. Pat. No. 2,272,195 an accumulating-type continuous wire drawing machine is shown having multiple reduction dies arranged in series with corresponding advancing blocks or drums positioned to successively draw wire through the respective dies. Each block is driven by a variable-speed motor controlled by an independent speed control rheostat. The block furthest downstream, known as the finishing or “master” block  20 , is preset to run at a constant speed, while the speed of each block preceding the master block can be independently regulated to compensate for wire elongation, as well as to control the amount of accumulation on each block. In the &#39;195 patent, these block speeds are manually adjusted by an operator observing the motion of guide rings  45 ,  45   a  and chains  46 ,  46   a  slidably mounted on each respective block. 
     However, most continuous wire drawing machines in operation today, especially non-accumulating type machines, utilize tension control arms, i.e. dancers to automatically and independently regulate the speed of corresponding motors and advancing blocks. They function to maintain constant wire tension and prevent wire breakage by detecting wire tension differentials between reduction dies. They are typically connected to rheostats which generate and transmit proportional electrical control signals to the motor of the corresponding advancing block or drum. In this manner a master block having a preset speed can reference the speeds of each of the preceding advancing blocks, and prevent wire breakage between reduction dies. 
     Additionally, various types of wire collection machines or “take-up” equipment have been developed to support wire drawing machines in the final packaging/bundling stage of wire production. In particular, wire collection machines known as “dead blocks” have been widely used to coil and collect wire into bundles. They do so by means of a rotary “flyer” mechanism which operates to coil or wrap wire around a stationary block or drum. Due to a taper on the stationary block, wire wrapped in this manner continues to move outward on the stationary block while maintaining sufficient tension to pull evenly, until the wire falls into a finished wire heap. The advantage of this is that wire can be coiled and removed with complete safety, regardless of coil speeds, and without interrupting the operation of the drawing machine. 
     In many cases an additional die is secured to the flyer to simultaneously draw and coil wire on the stationary block. This enhances the utility of the dead block by complementing wire drawing machines to produce even greater wire reductions. Moreover, because of their combined wire drawing and collection capabilities, these dead block machines can also be utilized as stand-alone production units capable of directly drawing wire rod from a spool, and not merely as ancillary equipment to wire drawing machines. One example of a dead block machine used as a stand-alone unit is a fixed double-deck dead block having a single block with two deck surfaces. While double-deck dead blocks operate to draw and collect wire as a single production unit, they typically have relatively slow operating speeds, and have a limited range of wire gauge reduction. Additionally, because double-deck dead block machines are driven by a single motor they cannot take advantage of the tension control arm feature described above. 
     BRIEF SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a simple and efficient double-draft wire drawing and collection machine capable of continuous and synchronized drawing and collection of wire. 
     It is a further object of the present invention to provide a simple and efficient double-draft wire drawing and collection machine having two wire drawing blocks, each driven by an independent motor. 
     It is a still further object of the present invention to provide a simple and efficient double-draft dead block machine for use as a stand-alone unit in wire drawing and collection. 
     The present invention is for a double-draft wire drawing and collection machine generally having a frame supported on a surface. The frame supports a first reduction die, and a rotary advancing block driven by a variable-speed first motor for drawing wire through the first reduction die. Additionally, a stationary block having a central axis for temporally collecting wire is also supported on the frame downstream from the rotary advancing block. A rotary means for coiling wire on the stationary block having an axis of rotation coaxial with the central axis is driven by a second motor at a constant speed to collect wire on the stationary block. A second reduction die which is secured to a radially distal point from the axis of rotation further reduces the wire in the process of collecting wire. Finally, the wire drawing and collection machine has means for regulating the speed of the rotary advancing block which includes a tension control arm for sensing wire tension differentials, and means for varying the speed of the first motor depending on the position of the tension control arm, in order to maintain constant wire tension between the rotary advancing block and the second reduction die. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a preferred embodiment of the double-draft continuous wire drawing and collection machine absent the frame, illustrating the directional flow of wire. 
     FIG. 2 is a schematic side view of the double draft wire drawing and collection machine illustrating the principle operative features. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings, FIGS. 1 and 2 show the double-draft wire drawing and collection machine with tension-sensitive speed control, generally indicated by reference character  10 . FIG. 2 is a schematic side view of the double-draft wire drawing and collection machine illustrating the relationship of the machines principle operative features. As can be seen in FIG. 2, the machine  10  includes a frame  11  upon which all other components and elements are supported on or secured to. The frame  11  itself is supported on a surface  12 , such as the floor of a wire production plant. Preferably, the frame  11  has access panels (not shown) for servicing the machine  10  during routine maintenance. Additionally, FIG. 1 shows a perspective view of a preferred embodiment of the wire drawing and collection machine  10 , absent the frame  11 . The frame  11  has been removed to detail the internal operation of the machine  10 , and to illustrate the directional flow of wire. 
     As can be seen in FIGS. 1 and 2, the machine  10  includes a first reduction die  15  suitably mounted and supported by the frame  11 . The first reduction die  15  is preferably a conventional wire reduction die having a construction for drawing wires at a desired percentage reduction. And the wire material to be drawn is preferably undrawn wire rod  13  from a pay-off spool  14 , but is not limited only to such. Wire rod  13  enters the first reduction die  15  where it undergoes a reduction in its cross-sectional area, and exits as once-drafted wire  16 . 
     As shown in FIGS. 1 and 2, wire rod  13  is drawn through the first reduction die  15  by means of a rotary advancing block  17  also supported on the frame  11  by suitable bearings and located downstream from the first reduction die  15 . The wire  16  is wrapped several times around the rotary advancing block  17  which preferably has a cylindrical configuration with a horizontal axis of rotation. And preferably still, the rotary advancing block  17  has a ring shaped lip  18  for decelerating the rotary advancing block  17  by means of a brake  53 . The rotary advancing block  17  is driven by a variable-speed first motor  22 , which is preferably a variable-speed DC electric motor. As can be seen in FIG. 1, a preferred embodiment of the machine  10  includes a drive train having a first drive belt  23 , and a transmission gearbox (not shown) which transfers power to the rotary advancing block  22  via a first drive shaft  26 . In FIG. 1, the transmission gearbox is illustratively represented by a first drive gear  24  and a first shaft gear  25  which engages the first drive gear  24  and drives the first drive shaft  26  and rotary advancing block  17  in the rotational direction indicated by reference character  19 . However, other transmission configurations are contemplated as understood and practiced in the relevant art. 
     Downstream from the rotary advancing block  16  is means for regulating the speed of the rotary advancing block  17 , generally indicated by reference character  45 . The means for regulating  45  operates to detect tension differentials by monitoring the magnitude of forces acting at right angles to the direction of wire travel. The means for regulating  45  includes, a tension control arm  47  or dancer  47  for sensing wire tension differentials between the rotary advancing block  17  and the second reduction die  32  (see FIG.  1 ). The tension control arm  47  has a first end  48  pivotally secured to the frame  11 , and a second end  49  opposite the first end  48  having a sheave  46 . As wire  16  passes around the sheave  46 , tension differentials in the wire  16  activates movement of the tension control arm  47 . 
     The means for regulating  45  also includes means for varying  50  the speed of the first motor  22  dependent on the position of the tension control arm  47  as determined by the wire  16  being withdrawn from the rotary advancing block  17 . Preferably the means for varying  50  is a rheostat which generates and transmits electrical control signals  51 ,  52  for accelerating the first motor  22  and decelerating the rotary advancing block  17 , respectively. The electrical control signal  52  for decelerating the rotary advancing block  17  actuates the brake  53  on the ring shaped lip  18  of the rotary advancing block  17 . The electrical control signals  51 ,  52  are proportional to the position of the tension control arm  47 , to accelerate or decelerate the rotary advancing block  17 , and thereby maintain constant wire tension. 
     In this manner, wire rod  13  is drawn through the first reduction die  15  by the rotary advancing block  17 . The wire  16  then passes around the sheave  46  of the tension control arm  47  and around sheaves  20  and  21  before traveling to the second reduction die  32 . In a preferred embodiment, as shown in FIG. 1, wire passage from the rotary advancing block  17  to the second reduction die  32  is through the hollow centers of the rotary advancing block  17  and the first and second drive shafts  26 ,  40 . As shown in FIG. 1, the sheaves  46 ,  20 , and  21  operate to redirect the wire  16  being withdrawn from the rotary advancing block  17  through the hollow center of the rotary advancing block  17 . 
     Downstream from the means for regulating  45  and after the wire  16  exits the first drive shaft  26 , it enters the second drive shaft  40  via inlet  41 . The second drive shaft  40  functions to drive a flyer  29  preferably in the shape of a wheel  29  or arm. Similar to the rotary advancing block  17 , the flyer  29  is independently driven by a second motor  36 , which is preferably a variable-speed DC electric motor. However, unlike the first motor  22 , the second motor  36  is preset to run at a constant speed. Consequently, the flyer  29  also rotates at a constant wire drawing and coiling speed. And preferably, the second motor  36  drives the flyer  29  by means of a second drive train having a second drive belt  37 , and a transmission gearbox (not shown) which transfers power to the flyer  29  via the second drive shaft  40 . In FIG. 1, the transmission gearbox of the second drive train is illustratively represented by a second drive gear  38  and a second shaft gear  39  which engages the second drive gear  38  and drives the second drive shaft  40  and flyer  29  in a rotational direction indicated by reference character  30 . 
     In this manner, the flyer  29  rotatably coils wire temporarily onto a stationary block  28 , also known as a “dead block” which is suitably and fixedly supported by the frame  11 . The stationary block  28  preferably has a tapered cylindrical configuration with a horizontally oriented center axis, and the flyer  29  has an axis of rotation coaxial with the center axis of the stationary block  28 . The wire  16  is directed out of the second drive shaft  40  through an opening  43  by a sheave  44 . Preferably, the wire  16  is then directed to a sheave  31  affixed to the flyer  29  which redirects the wire  16  into a second reduction die  32  also affixed to the flyer  29 . 
     Similar to the first reduction die  15 , the second reduction die  32  is preferably a conventional wire reduction die having a construction for drawing wires at a further desired percentage reduction. The once-drawn wire  16  enters the second reduction die  32  where it undergoes a further reduction in its cross-sectional area, and exits as twice-drafted wire  33 . Thus wire  16  is drawn through the second reduction die  32  by the rotational movement of the flyer  29  and coils the twice-drafted wire  33  onto the stationary block  28 . 
     As the twice-drafted wire  33  is collected on the stationary block  28 , the block taper of the stationary block  28  allows the wire  33  to adjust its own tension in order to pull evenly, and to feed Out on the stationary block  28  without excessive slippage or crossovers. Thus the wire  33  travels further out on the stationary block  28  where the wire  33  can be collected in a coiled bundle. And as can be seen in FIG. 1, an extended horn  34  is preferably utilized as an extension of the stationary block  28  whereby wire loops may fall and collect in a coiled wire heap  35  ready for transport. 
     The present embodiments of this invention are thus to be considered in all respects as illustrative and not restrictive; the scope of the invention being indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are intended to be embraced therein.