Abstract:
An automatic wire feed adjuster, including a feeding mechanism including a pair of rollers that feeds a wire therebetween, a tension controller that adjusts a tension between the pair of rollers, a wire speed sensor that measures a fed speed of the wire after exiting the feeding mechanism, and a control circuit that compares a driven speed of the wire with the fed speed of the wire, and that decides whether to instruct the tension controller to adjust the tension between the pair of rollers.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    Devices, systems, and methods consistent with the invention relate to an automatic feed adjuster. 
         [0003]    2. Description of the Related Art 
         [0004]    In the related art, there are various types of welding processes, including processes which utilize a continuous wire feed as a welding electrode. 
         [0005]    A diagrammatical representation of such a related art continuous wire feed welding process is illustrated in  FIG. 1 . In  FIG. 1 , a welding system  1  includes a control circuit  10 , a power source  20 , a motor  12 , and spool  30 . Spool  30  contains wire  35  spooled thereon. Motor  12  drives opposing rollers  14  to take up wire  35  from spool  30  and send it to gun  22 . The operator utilizes gun  22  to form a weld on workpiece  40 . As the weld is formed on workpiece  40 , wire  35  is consumed at gun  22 , and is replaced by feeding more wire  35  to gun  22  by action of motor  12  and rollers  14  at a constant rate. 
         [0006]    Different types of wires  35  are available for different welding applications. The selection of a particular type of wire depends on several factors, including, e.g., the type of material being welded, the weld design, material surface conditions, quality concerns, and process variation concerns. Due to these considerations, the different types of wires have widely varying diameters. 
         [0007]    As mentioned above, in the system illustrated in  FIG. 1 , wire  35  is fed to gun  22  at a constant rate during a welding operation. This rate is set by the operator via a variable knob on control circuit  10  before the welding operation begins. Different rates are appropriate for different welding applications. For example, a thicker material to be welded may require a faster feed, while a thinner material may require a slower speed to avoid burn-through. 
         [0008]    In order to provide the desired feed rate, an amount of tension between rollers  14  is also adjustable by the operator, before the welding operation begins. The term tension is broadly utilized in this context to represent both a “tension” force acting on each roller  14  in a direction toward the other (e.g., as created by a spring member connecting the two rollers  14 ) and as a “pressure” forcing the rollers  14  toward each other (e.g., as created by spring members on opposite sides of the two rollers  14 ). This tension between rollers  14  acts to draw wire  35  off of spool  30 , and feed wire  35  toward gun  22 . The adjustment is typically provided by a small thumb-wheel or other adjustment mechanism. 
         [0009]    The tension between rollers  14  is set in view of the diameter of the wire  35 , and remains constant during the welding operation. Unfortunately, if the tension between rollers  14  is set too high, the rollers  14  will deform the wire  35  as it passes therethrough. Such a deformed wire  35  can jam gun  22 . On the other hand, if the pressure between rollers  14  is set too low, wire  35  will be fed to gun  22  at an erratic rate, which results in an erratic welding arc and poor weld quality. 
         [0010]    Further, even if the tension is set properly on a first section of wire  35 , there is inherent variability in the diameter of wire  35  due to such factors as manufacturing process variation and/or damage during shipment or storage. In other words, wire  35  may not have a constant diameter along its length. Thus, as wire  35  is fed to gun  22  through rollers  14 , the tension set before the welding operation (in view of a beginning diameter of wire  35 ) might become inappropriate, and wire  35  might begin to deform or be erratically fed, as described above. 
         [0011]    The above problems demand an improvement in the related art system. 
       BRIEF SUMMARY OF THE INVENTION 
       [0012]    In one aspect of the invention, there is provided an automatic feed tension adjuster that overcomes the problems of the related art. 
         [0013]    In another aspect of the invention, there is provided an automatic wire feed adjuster, including a feeding mechanism comprising a pair of rollers that feeds a wire therebetween, a tension controller that adjusts a tension between the pair of rollers, a control circuit that decides whether to instruct the tension controller to adjust the tension between the pair of rollers. 
         [0014]    In another aspect of the invention, there is provided an automatic wire feed adjuster, including a feeding mechanism including a pair of rollers that feeds a wire therebetween, a tension controller that adjusts a tension between the pair of rollers, a wire speed sensor that measures a fed speed of the wire after exiting the feeding mechanism, and a control circuit that compares a driven speed of the wire with the fed speed of the wire, and that decides whether to instruct the tension controller to adjust the tension between the pair of rollers. 
         [0015]    In another aspect of the invention, there is provided an automatic wire feed adjuster, including a feeding mechanism for feeding a wire therethrough by applying a force to the wire, a force adjuster that adjusts the force applied to the wire, a control circuit that decides whether to instruct the force adjuster to adjust the force applied to the wire. 
         [0016]    In another aspect of the invention, there is provided an automatic wire feed adjuster, including a feeding mechanism for feeding a wire therethrough by applying a force to the wire, a force adjuster that adjusts the force applied to the wire, a wire speed sensor that measures a fed speed of the wire after exiting the feeding mechanism, and a control circuit that compares a driven speed of the wire with the fed speed of the wire, and that decides whether to instruct the force adjuster to adjust the force applied to the wire. 
         [0017]    In another aspect of the invention, there is provided a method of adjusting a wire feed, including feeding a wire through a driven pair of rollers having a tension therebetween, measuring a fed speed of the wire after it exits from between the pair of rollers, and deciding whether to adjust the tension between the pair of rollers. 
         [0018]    In another aspect of the invention, there is provided a method of adjusting a wire feed, including feeding a wire through a driven pair of rollers having a tension therebetween, measuring a fed speed of the wire after it exits from between the pair of rollers, comparing a driven speed of the wire with the fed speed of the wire, and deciding whether to adjust the tension between the pair of rollers. 
         [0019]    In another aspect of the invention, there is provided a method of adjusting a wire feed, including feeding a wire through a feeding mechanism that applies a force to the wire, measuring a fed speed of the wire after it exits from the feeding mechanism, and deciding whether to adjust the force applied to the wire. 
         [0020]    In another aspect of the invention, there is provided a method of adjusting a wire feed, including feeding a wire through a feeding mechanism that applies a force to the wire, measuring a fed speed of the wire after it exits from the feeding mechanism, comparing a driven speed of the wire with the fed speed of the wire, and deciding whether to adjust the force applied to the wire. 
         [0021]    In another aspect of the invention, there is provided a control circuit that decides whether to instruct a tension controller to adjust a tension between a pair of rollers in a feeding mechanism that feeds a wire therebetween. 
         [0022]    In another aspect of the invention, there is provided a tension controller that adjusts a tension between a pair of rollers in a feeding mechanism that feeds a wire therebetween in view of a comparison of a driven speed of the wire determined from the pair of rollers with the fed speed of the wire measured on the wire. 
         [0023]    The above stated aspects, as well as other aspects, features and advantages of the invention will become clear to those skilled in the art upon review of the following description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]    The above and/or other aspects of the invention will be more apparent by describing in detail exemplary embodiments of the invention with reference to the accompanying drawings, in which: 
           [0025]      FIG. 1  illustrates a diagrammatic representation of a welding system according to the related art; and 
           [0026]      FIG. 2  illustrates a diagrammatic representation of a welding system according to an embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0027]    Exemplary embodiments of the invention will now be described below by reference to the attached Figures. The described exemplary embodiments are intended to assist the understanding of the invention, and are not intended to limit the scope of the invention in any way. Like reference numerals refer to like elements throughout. 
         [0028]    In an exemplary embodiment of the invention, an automatic feed adjuster is utilized to provide optimized wire feeding and welding. 
         [0029]    More specifically, as shown in  FIG. 2 , welding system  101  includes control circuit  110 , power source  120 , motor  112 , tension control  115 , wire speed sensor  116 , user/data interface  118 , and spool  130 . Spool  130  contains wire  135  spooled thereon. Motor  112  drives opposing rollers  114  to take up wire  135  from spool  130  and send it to gun  122 . The operator utilizes gun  122  to form a weld on workpiece  140 . As the weld is formed on workpiece  140 , wire  135  is consumed, and is replaced by motor  112 . 
         [0030]    User/data interface  118  provides an input for data regarding wire  135  to be entered into welding system  101 . This wire data may include any particular information regarding the wire  135 , such as its diameter, length, configuration, manufacturer part number, internal part number, or any other physical, chemical or performance properties that may be useful. 
         [0031]    The user/data interface  118  may include, without limitation, any digital, analog, or manual device whereby an operator can enter wire data (e.g., a Graphical User Interface, a text based input system, adjustment knobs, sliders, etc.) or any device that reads wire data from wire  135  or its packaging (e.g., a RFID) reader, magnetic or optical drive, bar code reader, etc.). Further, data regarding wire  135  may also be stored within welding system  101  for later use (or pre-stored before use), and simply be accessed by the operator through user/data interface  118 . 
         [0032]    Welding system  101  then utilizes wire data for wire  135  to initially adjust, and continuously control, the tension between rollers  114  (via tension control  115 ). More specifically, tension control  115  first adjusts the tension between rollers  114  to a setting equal to an initial tension that is equal to a minimum amount of tension between rollers  114  necessary to feed wire  135  to gun  122  without slipping. This initial minimum tension is determined according to the wire data (e.g., a diameter) of wire  135 . The wire data may be input to welding system  101  as discussed above. 
         [0033]    Next, during the welding operation, as wire  135  is fed continuously through rollers  114 , the tension control operates to continuously adapt the tension between rollers  114  to maintain a minimum amount of tension between rollers  114  necessary to feed wire  135  to gun  122  without slipping. This operating minimum tension is determined by feedback data delivered to control circuit  110  from motor  112  and wire speed sensor  116 , as described below. 
         [0034]    The use of these minimum tensions avoids any erratic feeding of the wire  135  due to a tension that is set too low, and any possible deformation of the wire  135  due to a tension that is set too high. Further, as tension adjustments are accomplished automatically by tension control  115 , the possibility of operator error influencing the feeding of wire  135  is drastically reduced. 
         [0035]    As mentioned above, the operating minimum tension is determined by feedback data. More specifically, when the welding system  101  is feeding wire  135  via motor  112  and opposing rollers  114 , the control circuit  110  obtains a first wire speed of the wire  135  by measuring the speed of the motor  112  and taking into account the diameters of rollers  114 . Additionally, the control circuit  110  obtains a second wire speed from wire speed sensor  116 , which directly measures the speed of wire  135  as it passes thereby. Control circuit  110  then compares the first and second wire speeds. If the wire speeds are the same, no slipping of wire  135  on opposing rollers  114  is occurring, and no tension adjustment is necessary. Thus, the control circuit  110  does not instruct the tension control  115  to modify the tension of rollers  114 . 
         [0036]    However, if the first wire speed calculated from the motor speed is higher than the second wire speed read from the wire sensor  118 , the wire  135  is slipping on opposing rollers  114 . Thus, control circuit  110  will instruct the tension control  115  to increase the tension between opposing rollers  114  until the first and second wire speeds become equivalent (i.e., until the wire  135  stops slipping). 
         [0037]    Control circuit  110  will continue to increase the tension between opposing rollers  114  until it reaches a maximum value. The maximum value may be set in view of many factors, including a point at which the wire  135  will begin to deform because of the tension. This maximum value is determined according to the wire data (e.g., a diameter, type, size, etc.) of wire  135 . 
         [0038]    The sampling rate for determining the first and second wire speed is not limited, but should be set to optimize the welding operation. 
         [0039]    The wire speed sensor can be any sensor that is capable of providing the required wire speed data, including, without limitation, electronic or mechanical sensors that contact or do not contact the wire  135 . While the wire speed sensor in  FIG. 2  is positioned after rollers  114 , since the wire is continuous, the speed sensor can be placed at any point along the length of wire  135 . 
         [0040]    Opposing rollers  114  are illustrated in this exemplary embodiment. However, opposing rollers are not required, and the invention is not limited thereto. For example, the invention is equally applicable to system having more or less than two rollers, or to systems that use other driving concepts for wire  135  that create some kind of pressure on the wire. This pressure can be adjusted similarly to the tension described in the exemplary embodiment. 
         [0041]    Further, there is no limitation to the amount of rollers  114  that are powered by motor  112 . For example, one roller of the rollers  114  may be powered, and one roller may be an unpowered following roller. 
         [0042]    The term tension is broadly used in the context of this invention. It means either a “tension” force acting on each roller in a direction toward the other and as a “pressure” forcing the rollers toward each other. This tension can be created by spring members, elastic members, levers, electric motors, or any other such device. The amount of tension is adjustable by adjusting the pressure or tension exerted by these devices, which in turn adjusts the tension between the opposing rollers. The amount of pressure or tension exerted by the devices can be controlled by the tension control  115 , or other such component, via electrical or mechanical means. 
         [0043]    As mentioned above, the exemplary embodiment utilizes wire data to set an initial tension equal to a minimum amount of tension between rollers  114 . However, the invention is not limited thereto, and the initial tension may be set at a point between the minimum and maximum tension. Thereafter, the tension control may operate to reduce the tension until the feedback data indicates that there is slipping of the wire, at which point tension may again be increased according to the process described above. 
         [0044]    Although  FIG. 2  illustrates a single welding system  101  including spool  130 , motor  112 , opposing rollers  114 , tension controller  116  and wire speed sensor  118 , each of these elements may be independently provided, or grouped together in any desirable combination. For example, the roller  114  may be removably attached to a welding machine, located close to the machine, or built into the machine, depending on a particular manufacturer&#39;s style and type of machine. Further, the invention may be retrofitted to existing welding systems by adding the necessary components. 
         [0045]    The welding system described herein is applicable to any welding system that utilizes a wire feed. 
         [0046]    While the invention has been particularly shown and described with reference to exemplary embodiments thereof, the invention is not limited to these embodiments. It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the following claims.