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You are an expert at summarizing long articles. Proceed to summarize the following text: 
TECHNICAL FIELD 
     Embodiments of the present disclosure pertain to a rotary mixer and, more particularly, to an apparatus for material gradation control. 
     BACKGROUND 
     A rotary mixer may be used as a soil stabilizer to cut, mix, and pulverize native in-place soils with additives or aggregates to modify and stabilize the soil for a strong base. 
     A rotary mixer may also be used as a road reclaimer to pulverize a surface layer, such as asphalt, and can mix it with an underlying base to create a new road surface and stabilize deteriorated roadways. Optionally, a rotary mixer can add asphalt emulsions or other binding agents to create a new road surface during pulverization or during a separate mix pass. 
     In a conventional rotary mixer, an operator may visually inspect the milled (or reclaimed) surface and manually adjust the speed of the rotor, and/or the front and rear doors to adjust the degree of pulverization of the milled surface. By closing the rear door, more material is held within the chamber. Traditionally, this is what an operator uses for fine adjustments of gradation. But by closing the rear door to hold more material, the machine requires more power to turn the rotor through that material, which causes the machine to travel slower. 
     U.S. Pat. No. 5,190,398 issued to Swisher, Jr. on Mar. 2, 1993, discloses an apparatus for pulverizing a surface such as a road and a system for adding liquid to the surface being pulverized. 
     A conventional rotary mixer may also include a breaker bar that controls the degree of pulverization of the milled surface. The breaker bar is fixed, so that it is not possible to adjust the degree of pulverization. 
     SUMMARY 
     One aspect of the present disclosure is directed to a machine for receiving a ground layer, breaking up the ground layer into pieces, and producing a reclaimed layer incorporating the pieces, the machine including: a frame; a rotor coupled to the frame; a mixing chamber coupled to the frame and at least partially surrounding the rotor, the mixing chamber having an interior surface; a first member coupled to the interior surface and having an edge, the first member being moveable between a first position and a second position; and a gap length between the edge and the rotor, the gap length including: a first length when the first member is in the first position; and a second length when the first member is in the second position, the second length being greater than the first length. 
     Another aspect of the present disclosure is directed to a rotary mixer for receiving a ground layer, breaking up the ground layer into pieces, and producing a reclaimed layer incorporating the pieces, the rotary mixer including: a rotor; a mixing chamber at least partially surrounding the rotor and having an interior surface; and a first member coupled to the interior surface and having an edge, the first member being moveable between a first position at which the edge is a first distance from the rotor and a second position at which the edge is a second distance from the rotor, the second distance being greater than the first distance. 
     Another aspect of the present disclosure is directed to an adjustable sizing mechanism for a machine having a mixing chamber and a ground-engaging rotor, the adjustable sizing mechanism including: a first member having an edge; means for coupling the first member to the rotor chamber; and means for moving the edge from a first position to a second position. 
     Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates an exemplary machine having a mixing chamber; 
         FIG. 2  illustrates the mixing chamber of the exemplary machine shown in  FIG. 1 ; and 
         FIGS. 3 and 4  illustrate an exemplary adjustable sizing mechanism coupled to the interior surface of a mixing chamber. 
     
    
    
     DETAILED DESCRIPTION 
     Exemplary embodiments of the present disclosure are presented herein with reference to the accompanying drawings. Herein, like numerals designate like parts throughout. 
       FIG. 1  illustrates an exemplary machine  100 , in this case, a rotary mixer. Although  FIG. 1  shows a rotary mixer, any other machine used in road reclamation, soil stabilization, surface pulverization, or other applications is contemplated by the present disclosure. According to  FIG. 1 , the machine  100  includes a mixing chamber  102  and a frame  104 . 
       FIG. 2  illustrates a mixing chamber  102  of machine  100 . Mixing chamber  102  includes a rotor  202 , an adjustable sizing mechanism  204 , an interior surface  206 , a front door  208 , and a rear door  210 . As shown in  FIG. 2 , as machine  100  and mixing chamber  102  move along the ground, rotor  202  breaks apart and pulverizes an asphalt and base layer into pieces  212 , and pieces  212  are then used to form a layer of reclaimed material. One of skill in the art will appreciate that while  FIG. 2  shows an asphalt layer and a base layer, the present disclosure is applicable to other layers found during road reclamation. 
     The position of front door  208 , rear door  210 , and the speed of rotor  202  affects the degree of pulverization by regulating the amount, direction, and speed of material flow through mixing chamber  102 . Adjustable sizing mechanism  204  is also used to control the degree of pulverization of pieces  212 . Adjustable sizing mechanism  204 , as will be described below, may be positioned at various distances from rotor  202  to set the degree of pulverization or, in other words, to set the maximum size or diameter of pieces  212  used in the layer of reclaimed material. 
       FIG. 3  shows adjustable sizing mechanism  204  in a first position. Adjustable sizing mechanism  204  contains a first member  302 , a second member  304 , a third member  306 , and an edge  314 . First member  302  is coupled to interior surface  206  by, for example, a hinge that allows first member  302  to pivot from a position fixed on interior surface  206 . First member  302  and second member  304  are coupled to each other by, for example, a hinge. Second member  304  is coupled to interior surface  206  by, for example, a track  308 . Track  308  can either be built into interior surface  206  or coupled to interior surface  206 . An end of second member  304  moves along track  308 , thereby slidably coupling that end of second member  304  to interior surface  206 . In alternative embodiments, second member  304  could be coupled to interior surface  206  by other methods, so long as first member  302  was able to move relative to interior surface  206 . Second member  304  helps to hold first member  302 , and therefore the edge  314 , in place. 
     Third member  306  may optionally be connected to first member  302 . Third member  306  is constructed of a resilient and protective material and is placed between the first member  302  and the ground layer, to protect the first member  302  from sustaining damage from pieces  212 . Third member  306  may be coupled to first member  302 , for example by bolting or riveting, so that it can be easily removed and replaced if damaged or worn. Alternatively, first member  302  and third member  306  could be provided with grooves or slots that would allow third member  306  to slide onto first member  302  and lock in place. It is anticipated that third member  306  would need to be replaced from wear depending on the amount of time machine  100  is conducting pulverizing operations. 
     Adjustable sizing mechanism  204  may also contain an actuator  310  and a sensor  312  coupled to interior surface  206 . Actuator  310  links the adjustable sizing mechanism  204  to the hydraulic system of machine  100  so that adjustable sizing mechanism  204  is moved by operation of the hydraulic system of machine  100 . Alternatively, actuator  310  may optionally be located in either first member  302 , second member  304 , or on other locations of mixing chamber  102  or interior surface  206 . One of skill in the art will appreciate that adjustable sizing mechanism  204  may be moved by other means than hydraulic actuation. For example, adjustable sizing mechanism  204  may be moved by hand, by a chain gear, or by other methods known in the art. 
     Adjustable sizing mechanism  204  is coupled to interior surface  206  in such a way that a gap  320  is formed between adjustable sizing mechanism  204  and rotor  202 . The length of gap  320  determines the maximum diameter of pieces  212 . The length of gap  320  is defined by the distance between rotor  202  and adjustable sizing mechanism  204 . For example, the length of gap  320  may be determined by measuring the distance from edge  314  of first member  302  to rotor  202 . Sensor  312 , coupled to actuator  310 , uses actuator  310  to determine the position of the edge  314 . That is, sensor  312  measures the actuation of actuator  310 . The actuation of actuator  310  corresponds to a location of the edge  314 . According to various alternative embodiments, actuator  310  may be a variety of different types of actuators, such as hydraulic cylinders or screw-type actuators. 
     Alternatively, sensor  312  could be located on track  308  itself, on edge  314 , in the hinge rotatably coupling first member  302  to interior surface  206 , or on numerous other portions of adjustable sizing mechanism  204 , mixing chamber  102 , or interior surface  206  such that the output from sensor  312  could be used to calculate the position of edge  314 . For example, if the actuator  310  was located in the second member  304 , the sensor  312  could also be in second member  304 . 
     A second sensor (not shown) may be located on rotor  202 . Rotor  202  is often configured to move up or down in mixing chamber  102 , along a known path, and since rotor  202  has a fixed diameter, the second sensor could be used to sense the height of rotor  202  to know the position of rotor  202 . Then, a comparison can be made between sensor  312  and the second sensor to measure the length of gap  320 . 
     In  FIG. 3 , adjustable sizing mechanism  204  is shown in a first position where second member  304  is at one end of track  308 . In this first position, the length of gap  320  is minimized, as edge  314  is in the position closest to rotor  202 . When adjustable sizing mechanism  204  is in this first position, the maximum diameter of pieces  212  will be as small as mixing chamber  102  can produce. 
       FIG. 4  shows adjustable sizing mechanism  204  in a second position with the same components described with respect to  FIG. 3 . In this second position, second member  304  of adjustable sizing mechanism  204  is at the other end of track  308  from that shown in  FIG. 3 . In this second position, the length of gap  320  is maximized, as edge  314  is in the position farthest from rotor. When adjustable sizing mechanism  204  is in this second position, the maximum diameter of pieces  212  will be as large as mixing chamber  102  can produce. 
     INDUSTRIAL APPLICABILITY 
     The present disclosure contemplates that the length of gap  320 , which is calculated based on the signal received from sensor  312  and the second sensor, would be communicated to the operator of machine  100 . This information may be communicated either through wired or wireless communication systems well known in the art. With this length of gap  320  information, the operator of machine  100  would be able to move adjustable sizing mechanism  204  to a desired length of gap  320  to control the maximum diameter of pieces  212 . Potentially, the length of gap  320  could be displayed on a control panel in the operator station of machine  100  or on a remote control that the operator could use if observing machine  100  and mixing chamber  102  from the ground. The control panel in the operator station and/or the remote control may also be equipped with controls to allow the operator to move adjustable sizing mechanism  204  to the desired length of gap  320 . 
     By having adjustable sizing mechanism  204  on interior surface  206  of mixing chamber  102  of machine  100 , the performance of machine  100  may be enhanced. The operator of machine  100  will now have far greater control over material gradation and can even make adjustments during operation of machine  100 . Adjustable sizing mechanism  204  generally provides the operator with the ability to adjust the diameter of pieces  212  based on a variety of conditions. This is a benefit since one reclaiming job may require a different maximum diameter of pieces  212  than a second reclaiming job. 
     One of ordinary skill in the art will appreciate that while the adjustable sizing mechanism  204  has been described having a first member  302 , a second member  304 , and a third member  306 , that an adjustable sizing mechanism may have only a single member or it may have a plurality of members. The present disclosure should not be read to limit the adjustable sizing mechanism to having three members. Likewise, while  FIGS. 2-4  have shown adjustable sizing mechanism  204  located at a specific point of interior surface  206 , the present disclosure contemplates that adjustable sizing mechanism  204  may be located anywhere along interior surface  206  of mixing chamber  102 . Additionally, while adjustable sizing mechanism  204  has been described as an apparatus that couples with the interior surface  206  of mixing chamber  102 , one of skill in the art will appreciate that adjustable sizing mechanism  204  may be coupled to other parts of mixing chamber  102  within interior surface  206 , and be actuated to move in and out of interior surface  206  to change the length of gap  320 . 
     Although certain embodiments have been illustrated and described herein for purposes of description, it will be appreciated by those of ordinary skill in the art that a wide variety of alternate and/or equivalent embodiments or implementations calculated to achieve the same purposes may be substituted for the embodiments shown and described without departing from the scope of the present disclosure. Those with skill in the art will readily appreciate that embodiments in accordance with the present invention may be implemented in a very wide variety of ways. This application is intended to cover any adaptations or variations of the embodiments discussed herein. Therefore, it is intended that embodiments in accordance with the present invention be limited only by the claims and the equivalents thereof.

Summary:
A machine for receiving a ground layer, breaking up the ground layer into pieces, and producing a reclaimed layer incorporating the pieces, the machine including: a frame; a rotor coupled to the frame; a mixing chamber coupled to the frame and at least partially surrounding the rotor, the mixing chamber having an interior surface; a first member coupled to the interior surface and having an edge, the first member being moveable between a first position and a second position; and a gap length between the edge and the rotor, the gap length including: a first length when the first member is in the first position; and a second length when the first member is in the second position, the second length being greater than the first length.