Abstract:
A method of controlling a hydraulic system having a hydraulic lift function and an auxiliary function includes disabling the hydraulic lift function and the auxiliary function by routing pump flow to tank and opening the lift function and auxiliary function to tank with a single valve; enabling the lift function by closing pump flow to the auxiliary function and routing pump flow to the lift function with the single valve; and enabling the auxiliary function by closing pump flow to the lift function and routing pump flow to the auxiliary function with the single valve.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/986,176 filed Apr. 30, 2014, which is hereby incorporated herein by reference. 
     
    
     FIELD OF INVENTION 
       [0002]    The present invention relates generally to a fluid control valve and to a fluid system, and more particularly to a hydraulic fluid control valve and hydraulic fluid system that include primary function controls and auxiliary function controls. 
       BACKGROUND 
       [0003]    Fluid control valves and systems are used in a wide variety of applications for causing and controlling motion of various components. Hydraulic fluid control valves and systems are used in such applications when relatively large forces are to be transmitted and controlled through such components. 
         [0004]    One type of hydraulic fluid system may include a hydraulic pump for providing hydraulic fluid under pressure at a certain maximum rate, primary components that use the hydraulic fluid under pressure to operate primary functions, auxiliary or secondary components that use the hydraulic fluid under pressure to operate auxiliary functions, and a hydraulic fluid control valve that directs the hydraulic fluid under pressure to the primary or auxiliary components at a rate commanded by the operator. In such systems, it is sometimes desirable to inhibit hydraulic fluid flow to the auxiliary components when hydraulic fluid is flowing to the primary components, and/or to inhibit hydraulic fluid flow to the primary components when hydraulic fluid is flowing to the auxiliary components. 
       SUMMARY OF INVENTION 
       [0005]    Preferred embodiments eliminate fluid flow to primary function components when auxiliary function components are actuated, even when the auxiliary function components are in a high pressure condition and the primary function control spool is in an actuated or open position. Preferred embodiments also provide additional features and advantages described below. 
         [0006]    According to one aspect of the invention, a sectional fluid control valve system includes a combined inlet and auxiliary work section upstream of the primary work section; the combined work section including a pump inlet, an auxiliary work port, a pump pressure passage, and a valve member intermediate the pump inlet and the auxiliary work port and intermediate the pump inlet and the pump pressure passage; the valve member having a disable position substantially disabling fluid pressure communication from the pump inlet to the auxiliary work port and from the pump inlet to the combined section pump pressure passage; the valve member having a primary enable position closing fluid pressure communication between the pump inlet and the auxiliary work port and opening fluid pressure communication between the pump inlet and the combined section pump pressure passage; and the valve member having an auxiliary enable position closing fluid pressure communication between the pump inlet and the combined section pump pressure passage and opening fluid pressure communication between the pump inlet and the auxiliary work port. 
         [0007]    Optionally, the system includes a primary work section. The primary work section includes a pump pressure passage and a primary work port, wherein the combined inlet and auxiliary work section is upstream of the primary work section, wherein the pump pressure passage of the combined inlet and auxiliary work section is in fluid communication with the pump pressure passage of the primary work section. 
         [0008]    Optionally, the disable position fluidly connects the auxiliary work port and the combined section pump pressure passage to tank. 
         [0009]    Optionally, the primary enable position fluidly connects the auxiliary work port to tank. 
         [0010]    Optionally, the auxiliary enable position fluidly connects the combined section pump pressure passage to tank. 
         [0011]    Optionally, the disable position fluidly connects the pump inlet to tank. 
         [0012]    Optionally, a bypass compensator section is intermediate the combined work section and the primary work section. 
         [0013]    Optionally, the primary work section includes a valve member intermediate the pump pressure passage and the primary work port, and a compensator that maintains a substantially fixed pressure drop across the valve member. 
         [0014]    Optionally, a primary hydraulic motor is in fluid communication with the primary section work port, an auxiliary hydraulic motor in fluid communication with the combined section work port, and a hydraulic pump having an outlet in fluid communication with the pump inlet port. 
         [0015]    Optionally, a vehicle has a prime mover, the prime mover is drivingly connected to the hydraulic pump, the primary hydraulic motor is drivingly connected to a man lift multiple boom mechanism on the vehicle, and the auxiliary hydraulic motor is drivingly connected to a work tool. 
         [0016]    Optionally, the combined work section includes a housing, the housing includes a front surface and a top surface and end surfaces, electrical solenoids are connected to one of the end surfaces for moving the valve member between its positions, the pump inlet port is disposed on the top surface, and the auxiliary work port is disposed on the bottom surface and on the front surface. 
         [0017]    According to another aspect, a method of controlling a hydraulic system having a hydraulic lift function and an auxiliary function includes disabling the hydraulic lift function and the auxiliary function by routing pump flow to tank and opening the lift function and auxiliary function to tank with a single valve; enabling the lift function by closing pump flow to the auxiliary function and routing pump flow to the lift function with the single valve; and enabling the auxiliary function by closing pump flow to the lift function and routing pump flow to the auxiliary function with the single valve. 
         [0018]    Optionally, enabling the lift function includes fluidly connecting the auxiliary function to tank with the single valve. 
         [0019]    Optionally, enabling the auxiliary function includes fluidly connecting the lift function to tank with the single valve. 
         [0020]    The foregoing and other features of the invention are hereinafter described in greater detail with reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]      FIG. 1  is a schematic diagram of a hydraulic circuit of a conventional hydraulic fluid control valve and system; 
           [0022]      FIG. 2  is a graph illustrating pressures and flow rates at various locations of the valve and system illustrated in  FIG. 1  at various times under various conditions; 
           [0023]      FIG. 3  is a schematic diagram of a hydraulic circuit of an exemplary hydraulic fluid control valve and system; 
           [0024]      FIG. 4  is a graph illustrating pressures and flow rates at various locations of the valve and system illustrated in  FIG. 3  at various times under various conditions; 
           [0025]      FIG. 5  is a front view of an exemplary combined inlet enable and auxiliary work section of an exemplary hydraulic fluid control valve; and 
           [0026]      FIG. 6  is a top view of an exemplary combined inlet enable and auxiliary work section of an exemplary hydraulic fluid control valve illustrated in  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION 
       [0027]    Referring now to the drawings in greater detail,  FIG. 1  illustrates a prior art hydraulic valve  10  and a prior art hydraulic system  11 . The valve  10  includes an enable inlet section  12 , a bypass compensator section  13 , an auxiliary or secondary work section  14 , a primary work section  15 , and an outlet section  16 . Additional valve sections (not shown) may also be provided in hydraulic valve  10 , such as, for example, additional primary valve work sections (not shown) that will be downstream of section  14  and similar to or identical to valve section  15 . The hydraulic system  11  includes the valve  10 , a hydraulic pump  17 , an auxiliary or secondary function hydraulic motor or cylinder  18 , a primary function hydraulic motor or cylinder  19 , and a hydraulic tank or reservoir  20 . 
         [0028]    The valve sections  12 - 16  of hydraulic valve  10  are each known valve sections which may be, for example, cast and machined metal valve sections that are bolted together to provide a unitary hydraulic valve  10 . Each valve section  12 - 15  includes valve spools and passages shown schematically in  FIG. 1 . Valve section  16  does not include any valve spools, but does include passages as shown schematically in  FIG. 1 . The hydraulic pump  17  may be any suitable fixed or variable displacement hydraulic pump and may be, for example, a fixed displacement hydraulic gear pump. Alternatively, the pump  17  may be a variable displacement pump, in which case the bypass compensator valve section  13  would not be provided and load sense signals from valve  10  would control the output displacement of the pump. The pump  17  is driven by a prime mover  21  that may be, for example, an internal combustion engine or electric motor or other prime mover such as, for example, a prime mover disposed on a stationary or movable structure  22 . The structure  22  may be, for example, a vehicle, and the prime mover  21  may, for example, propel the vehicle  22  in which the prime mover  21  is mounted. The vehicle  22  may be any suitable land or marine or air or space vehicle, such as, for example, an over the highway truck. The vehicle  22  may include any suitable primary function hydraulic device  23 , such as, for example an aerial lift multiple boom mechanism that may be moved vertically or horizontally or rotated by primary hydraulic motor  19 . The primary function hydraulic motor  19  may be any suitable hydraulic motor on the vehicle  22 , such as, for example, a hydraulic motor that rotates the aerial lift multiple boom mechanism  23 . The auxiliary function hydraulic motor  18  may be any suitable hydraulic motor that can be added to the vehicle  22 , such as, for example, a hydraulic motor that drives a chain saw or cutter or any other auxiliary or secondary equipment  24  used by the operator of the vehicle  22  when the vehicle  22  is stationary and the operator is in the aerial lift multiple boom mechanism  23 . The term “hydraulic motor” means any rotary or linear hydraulic device that is actuated by hydraulic fluid under pressure, such as, for example, a hydraulic cylinder or rotary actuator or gerotor motor or any other hydraulic motor. 
         [0029]    Enable inlet valve section  12  includes an enable valve member or spool  12   a  that is movable between a disable position directing fluid flow from pump  17  to tank  20  to preclude actuation of hydraulic motors  18  and  19  when vehicle  22  is being driven and an enable position illustrated in  FIG. 1 . In the enable position, valve  12   a  directs fluid flow from pump  17  to bypass compensator  13   a  of valve section  13  and to valve sections  14 - 16 . The valve  10  includes an internal tank passage  25 , an internal pump pressure passage  26 , a primary load sense logic circuit or gallery  27 , and a secondary load sense logic circuit or gallery  28 . Primary load sense logic circuit  27  communicates the highest load demand pressure in system  11  to bypass compensator  13   a , which restricts fluid flow from pump  17  to tank passage  25  and causes pump pressure in pump pressure passage  26  to increase to a predetermined differential above such highest load demand pressure in a known manner. 
         [0030]    When auxiliary work section valve member or spool  14   a  of auxiliary work section  14  is shifted downward as viewed in  FIG. 1  to actuate the auxiliary components including auxiliary hydraulic motor  18  and auxiliary equipment  24 , auxiliary hydraulic motor  18  is supplied with hydraulic fluid under pressure from pump pressure passage  26  through auxiliary pre-compensator  14   b  of auxiliary work section  14  to maintain a substantially constant pressure differential across spool  14   a  in a known manner. Hydraulic fluid flows through hydraulic motor  18  to operate auxiliary equipment  24  and is returned to tank  20  through an external connection (not shown). 
         [0031]    Auxiliary work section spool  14   a  of auxiliary work section  14  in this position also connects secondary load sense logic circuit  28  to tank  20 , and this causes primary work section pre-compensator  15   b  of primary work section  15  to close because there is no or low load sense pressure in secondary load sense circuit  28  biasing pre-compensator  15   b  toward a closed position. By closing pre-compensator  15   b  when auxiliary work section spool  14   a  connects pump pressure to auxiliary hydraulic motor  18 , open pressure communication to primary hydraulic motor  19  from pump pressure passage  26  is blocked. In this manner, even if primary work section valve member or spool  15   a  of primary work section  15  is intentionally or unintentionally moved to an open position (which is a downward or upward position from the position viewed in  FIG. 1 ), substantial fluid flow or fluid pressure to primary hydraulic motor  19  is blocked by closed primary work section pre-compensator  15   b.    
         [0032]    This operation of prior art valve  10  and system  11  under the condition described above in which secondary or auxiliary work section  14  is actuated by moving spool  14   a  to its actuated position (downward from the position shown in  FIG. 1 ) is illustrated in  FIG. 2 . When the auxiliary work section  14  is so actuated and the primary work section compensator  15   b  is blocking open fluid pressure communication between the pump pressure passage  26  and primary work section control spool  15   a , fluid flow is blocked to primary hydraulic motor  19  when primary work section control spool  15   a  is in its de-actuated position shown in  FIG. 1 . However, if primary work section control spool  15   a  is moved downward or upward from its  FIG. 1  de-actuated position to its actuated or open position, under certain conditions a relatively small fluid pressure increase and a relatively small fluid flow rate can be communicated to primary hydraulic motor  19  and cause limited creep of primary hydraulic device  23 . This may occur when auxiliary function hydraulic motor  18  is operating at relatively high fluid pressures, such as, for example, under deadhead conditions. This relatively high fluid pressure under this condition exists in pump pressure line  26  on one side (orifice side) of pre-compensator spool  15   b  while low tank pressure exists on the other side (spring side) of pre-compensator spool  15   b . Under certain conditions when this occurs, pre-compensator spool  15   b  may communicate limited pressure and flow to the actuated (or open) primary control spool  15   a  and to hydraulic motor  19 , either by leakage or by oscillation of pre-compensator spool  15   b  or both. 
         [0033]    This condition is illustrated in  FIG. 2 , in which inlet or pump pressure (line  29 ) is indicated at 2421 pounds per square inch (psi) and load sense pressure (line  30 ) for auxiliary hydraulic motor  18  is indicated at 2197 psi, which may indicate a deadhead condition for auxiliary hydraulic motor  18 . Under this condition, pressure (line  31 ) communicated to hydraulic motor  19  through work port A of primary work section  15  may be on the order of 94 psi and flow (line  32 ) may be on the order of 1.4 gallons per minute (gpm), resulting in minimal creep of primary hydraulic device  23  if primary control spool  15   b  is actuated or open at time 31 seconds. If this occurs, the operator can move primary control spool  15   b  to its de-actuated or closed position to eliminate such creep if it is not desired. 
         [0034]    The presently preferred embodiment of the present invention, as illustrated in  FIGS. 3-6 , eliminates the above described fluid flow and minimal creep of primary function hydraulic motor  19  and primary function device  23  under the described conditions when both the auxiliary function work section control spool and the primary function work section control spool are actuated or open, even when the auxiliary hydraulic motor is in a high pressure condition. Further, the present invention combines the enable inlet section with the auxiliary work section to thereby eliminate one section from the prior art valve  10 , eliminates the secondary load sense gallery from the prior art valve  10  to eliminate seals and check valves and to eliminate drilling or otherwise machining secondary load sense passages, and maximizes system integration while simplifying the hydraulic circuit. 
         [0035]    Turning now to  FIG. 3 , a hydraulic valve  120  and a hydraulic system  121  according to the preferred embodiment of the invention are illustrated. The valve  120  includes a combined enable inlet and auxiliary work section  122 , a bypass compensator section  123 , a primary work section  125 , and an outlet section  126 . Additional valve sections (not shown) may also be provided in hydraulic valve  120 , such as, for example, additional primary valve work sections (not shown) that may be downstream of section  125  and similar to or identical to valve section  125 . The hydraulic system  121  includes the valve  120 , a hydraulic pump  127 , an auxiliary or secondary function hydraulic motor or cylinder  128 , a primary function hydraulic motor or cylinder  129 , and a hydraulic tank or reservoir  130 . 
         [0036]    The valve sections  122 - 126  of hydraulic valve  120  each may be, for example, cast and machined metal valve sections that are bolted together to provide a unitary hydraulic valve  120 . Each valve section  122 - 125  includes valve spools and passages shown schematically in  FIG. 3 . Valve section  126  does not include any valve spools, but does include passages as shown schematically in  FIG. 3 . The hydraulic pump  127  may be any suitable fixed or variable displacement hydraulic pump and may be, for example, a fixed displacement hydraulic gear pump. Alternatively, the pump  127  may be a variable displacement pump, in which case the bypass compensator valve section  123  would not be provided and load sense signals from valve  120  would control the output displacement of the pump. The pump  127  is driven by a prime mover  131  that may be, for example, an internal combustion engine or electric motor or other prime mover such as, for example, a prime mover disposed on a stationary or movable structure  132 . The structure  132  may be, for example, a vehicle, and the prime mover  131  may, for example, propel the vehicle  132  in which the prime mover  131  is mounted. The vehicle  132  may be any suitable land or marine or air or space vehicle, such as, for example, an over the highway truck. The vehicle  132  may include any suitable primary function hydraulic device  133 , such as, for example an aerial lift multiple boom mechanism that may be moved vertically or horizontally or rotated by primary hydraulic motor  129 . The primary hydraulic motor  129  may be any suitable hydraulic motor on the vehicle  132 , such as, for example, a hydraulic motor that rotates the aerial lift multiple boom mechanism  133 . The auxiliary hydraulic motor  128  may be any suitable hydraulic motor on the vehicle  132 , such as, for example, a hydraulic motor that drives a chain saw or cutter or other auxiliary or secondary equipment  134  used by the operator of the vehicle  132  when the vehicle  132  is stationary and the operator is in the aerial lift multiple boom mechanism  133 . The term “hydraulic motor” means any rotary or linear hydraulic device that is actuated by hydraulic fluid under pressure, such as, for example, a hydraulic cylinder or rotary actuator or gerotor motor or other hydraulic motor. 
         [0037]    Combined valve section  122  includes a three position four way solenoid valve member or spool  122   a  that is movable between a center disable position illustrated in  FIG. 3  connecting auxiliary hydraulic motor  128  and primary hydraulic motor  129  to tank  130 , an upward or first or primary function enable position directing fluid flow from pump  127  to pump pressure passage  136  and primary hydraulic motor  129  while connecting auxiliary hydraulic motor  128  to tank  130 , and a downward or second or auxiliary function enable position directing fluid flow from pump  127  to auxiliary hydraulic motor  128  while connecting pump pressure passage  136  and primary hydraulic motor  129  to tank  130 . The valve  120  includes an internal tank passage  135 , an internal pump pressure passage  136 , and a primary load sense logic circuit or gallery  137 . Primary load sense logic circuit  137  communicates the highest load demand pressure in system  121  to bypass compensator  123   a , which restricts fluid flow from pump  127  to tank passage  135  and causes pump pressure in pump pressure passage  136  to increase to a predetermined differential above such highest load demand pressure when valve  122   a  is in its above described first or primary enable position. Because the combined valve  122   a  connects the auxiliary hydraulic motor  128  to tank  130  when the primary work section  125  and primary hydraulic motor  129  are enabled, pressure and flow from pump  127  to the auxiliary hydraulic motor  128  is limited to leakage under this condition. Similarly, because the combined valve  122   a  connects the primary hydraulic motor  129  to tank  130  when the auxiliary hydraulic motor  128  is enabled, pressure or flow to the primary hydraulic motor  129  is limited to leakage under this condition even when the auxiliary hydraulic motor  128  is at a high pressure condition such as a deadhead condition. 
         [0038]    This operation of valve  120  and system  121  under the auxiliary enable condition described above in which the combined valve spool  122   a  is in its auxiliary enable (or downward from the position viewed in  FIG. 3 ) position and primary work section  125  valve member or spool  125   a  is actuated is illustrated in  FIG. 4 . Inlet or pump pressure (line  139 ) is indicated at 4243 pounds per square inch (psi), and auxiliary hydraulic motor  128  pressure (line  140 ) for auxiliary hydraulic motor  128  is indicated at 4000 psi, which may indicate a deadhead condition for auxiliary hydraulic motor  128 . Under this condition, measured pressure at the work port of primary work section  125  was on the order of 27 psi and measured flow was on the order of 0.0 (gpm), resulting in zero creep of primary hydraulic motor  129  and primary hydraulic device  133 . The hydraulic valve  120  is a substantially different size than the valve  10  described above, and comparisons of the graphs of  FIGS. 2 and 4  should take such differences in the valves  10  and  120  into account. 
         [0039]    Referring now to  FIGS. 5 and 6 , the housing  150  for the three position four way combined inlet enable and auxiliary work section  122  of valve  120  is illustrated. Solenoid operators  122   c  and  122   d  extend from one side surface of housing  150  and are aligned with one another and with spool  122   a  of section  122 . Auxiliary function relief valve  122   b  extends from an opposite side surface of housing  150  and has its spool in parallel alignment with solenoid operators  122   c  and  122   d  and with spool  122   a . Pump inlet port  122   e  extends from the top of housing  150 . Auxiliary ports  122   f  and  122   g  extend from the bottom surface and front surface, respectively, of the housing  150 . Tie rod holes  122   h  extend between the front and back sides of the housing  150 , and tie rods (not shown) hold the sections of valve  120  together. 
         [0040]    There are various benefits of the preferred embodiment of this invention with respect to the prior art solution. One benefit is that this invention simplifies the hydraulic sectional main control valve. It does this by eliminating one of the sections in the hydraulic sectional main control valve and eliminating one check valve cartridge per work section in the valve bank. The prior art solution shows the auxiliary function as the first work section in the hydraulic sectional main control valve, whereas the preferred embodiment has the auxiliary function integrated into the enable inlet. Regardless of which solution is chosen, the hydraulic sectional main control valve must have an enable inlet, so by integrating the auxiliary function into the enable inlet one work section can be eliminated from the hydraulic sectional main control valve. The check valve cartridges purpose is to inhibit any communication of high pressure oil from the auxiliary function in the form of leakage into the “B” work port, into the section compensator spool of a given downstream work section. Since we are eliminating the auxiliary function work section this check valve cartridge becomes unnecessary. 
         [0041]    Another benefit is that the preferred embodiment performs the disable feature, better than the prior art solution. The prior art solution performs this feature by diverting the load sense pressure from all of the downstream work sections to the internal tank circuit within the hydraulic sectional main control valve, whenever the auxiliary function is actuated. The reason that this solution works most of the time, is because flow to the work port is developed by the spring setting in the section compensator. Load sense pressure is essentially a hydraulic signal of pressurized oil transmitted from the work port to various parts of the hydraulic sectional main control valve. Load sense pressure in all work sections gets transmitted to the load sense signal gallery and to the section compensator spring chamber whenever a work section is activated. In every work section there is a shuttle valve (two way check valve) which compares the load sense pressure from a specific work section to the load sense pressure that is already in the load sense signal gallery. The series of shuttle valves will transmit the load sense pressure from the highest loaded work section to the load sense relief valve and to the margin pressure control device, which can either be a variable displacement load sensing pump or a bypass compensator. The margin pressure is the pressure at the outlet of the pump minus the load sense pressure being sent from the hydraulic sectional main control valve. The margin pressure is the differential pressure that is available to do work across the hydraulic circuit. When a work section is activated pressurized oil from the inlet will flow to the section compensator. There will be a differential pressure that develops across the ends of the section compensator spool and is used to position the section compensator spool. This differential pressure is the pressure upstream of the main control spool minus the quantity of load sense pressure for that specific work section plus the section compensator spring setting (upstream work section pressure−(LS pressure+compensator spring pressure)). The section compensator spool adjusts its position to obtain a force balance between these pressures. It will open further or close further to modify the pressure coming into it from the inlet to set the pressure upstream of the main control spool, to equal the load sense pressure plus the section compensator spring pressure. So the pressure downstream of the main control spool equals the load sense pressure and the pressure upstream of the main control spool equals load sense pressure plus the section compensator spring pressure. Thus the section compensator spring establishes the differential pressure across the main control spool. The differential pressure across the main control spool along with the area opening of the main control spool contribute in developing the flow rate that gets transmitted to the work port, per the Bernoulli Equation. If the load sense pressure that is transmitted to the load sense signal gallery and to the section compensator spring chamber is also connected to the internal tank circuit then the differential pressure across the main control spool is greatly reduced. In most cases the differential pressure is negative which means that no flow will be transmitted to the work port. However if the pressure required to get an implement to move, is close to the pressure in the internal tank circuit then there can be a positive differential pressure across the main control spool hence, flow going to the work port. This scenario has been seen and validated in a laboratory environment, on a piece of equipment, and illustrated in the drawings. 
         [0042]    The preferred embodiment performs this feature by isolating the auxiliary function from the rest of the hydraulic sectional main control valve functions. The auxiliary function is actuated by diverting all pump flow to the auxiliary function, via the three position four way solenoid valve in the enable inlet. When all of the pump flow is going to the auxiliary function, the rest of the functions in the hydraulic sectional main control valve are connected to the internal tank circuit. Since the entire hydraulic sectional main control valve is at the same pressure via the internal tank circuit, there isn&#39;t a differential pressure available to create a potential for flow to the work port, even if a work section is actuated. 
         [0043]    Although the invention has been shown and described with respect to a certain embodiment or embodiments, it is obvious that equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of this specification and the annexed drawings. In particular regard to the various functions performed by the above described elements (components, assemblies, devices, compositions, etc.), the terms (including a reference to a “means”) used to describe such elements are intended to correspond, unless otherwise indicated, to any element which performs the specified function of the described element (i.e., that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the herein illustrated exemplary embodiment or embodiments of the invention. In addition, while a particular feature of the invention may have been described above with respect to only one or more of several illustrated embodiments, such feature may be combined with one or more other features of the other embodiments, as may be desired and advantageous for any given or particular application.