Differential Impulse Conveyor

Abstract

A differential impulse conveyor system includes a detectable marker positioned in series on a movable component of the conveyor system. A fixed sensor positioned proximate the marker generates a signal when the movable component is in a first range of motion that positions the marker proximal to the sensor, and the sensor generates no signal when the movable component is not in the first range of motion. The sensor signal causes a current regulator to adjust current from a current source to operate a motor to move the conveyor tray at a first acceleration in a first mode, and the absence of a signal causes the current regulator to operate the motor to move the conveyor tray at a second acceleration in a second mode. The marker may be positionable to optimize timing of the current modes.

Description

[Technical field]

[0001] The present invention relates to a differential impulse conveyor used to transport items from a first location to a second location remote from the first location. More particularly, the present invention relates to a differential impulse conveyor having a reciprocating tray powered by a variable speed electric motor, the differential impulse conveyor having a movable counterweight assembly having a center of gravity aligned with the center of gravity of the conveyor tray. [Background technology]

[0002] A differential impulse conveyor is a conveyor that moves items by reciprocating an elongated conveyor tray on which the items are placed. The conveyor tray moves in a first direction with a first acceleration, then reverses direction of movement and moves in a second, opposite direction with a second acceleration greater than the first acceleration. The first acceleration is selected to prevent slippage of items on the conveyor tray so that the items move with the conveyor tray in the first direction. The second acceleration, greater in absolute value (i.e., in the opposite direction) than the first acceleration, is selected to cause items on the conveyor tray to slip or slide on the conveyor tray as the conveyor tray returns to its original position. By repeating this cycle of movement, the items move along the conveyor tray in the first direction. The first acceleration, the second acceleration, and the stroke or distance over which the conveyor tray reciprocates can be optimized to provide a desired speed of movement of the items being conveyed.

[0003] Some differential impulse conveyors use a motor that operates as a constant speed and an eccentrically mounted pulley or an angular universal joint connection to cyclically change the speed of the mechanical (shaft) output to the conveyor tray. Summary of the Invention

[0004] One embodiment of a differential impulse conveyor of the present invention includes an electric motor having an output shaft that can be rotated by the motor at two different angular velocities, a reciprocable conveyor tray for conveying items therein, a first rotary-to-linear reciprocating motion converter (as disclosed in U.S. Pat. No. 10,131,503) coupled between the output shaft of the electric motor and the conveyor tray, a reciprocable counterweight assembly having a trough therein configured to movably receive at least a portion of the conveyor tray therein, a second rotary-to-linear reciprocating motion converter coupled between the output shaft of the electric motor and the counterweight assembly, at least one sensor which can be, for example, an optical sensor, a magnetic sensor, and an electronic sensor, and one or more detectable markers, such as, for example, but not limited to, one or more optically detectable markers, one or more magnetically detectable markers, one or more electronically detectable markers, disposed on a moving surface of a component of the differential impulse conveyor, such as, for example, but not limited to, the conveyor tray, the counterweight assembly, or either the first rotary-to-linear reciprocating motion converter or the second rotary-to-linear reciprocating motion converter. These four components of some embodiments of the differential impulse conveyor of the present invention move in cyclical lockstep, and any of the movements can be used, along with one or more applied detectable markers and sensors, to control a current regulator.

[0005] As discussed in more detail below, conveyor tray movement in differential impulse conveyor embodiments of the present invention is advantageously controlled in a manner that can increase efficiency, reduce manufacturing costs, and reduce maintenance costs compared to conventional differential impulse conveyors. Additionally, differential impulse conveyor embodiments of the present invention allow access to the floor space below the conveyor for improved cleaning and sanitation.

[0006] One embodiment of the differential impulse conveyor of the present invention includes a variable frequency motor that changes between a first mode to produce a first acceleration of the conveyor tray and a second mode to produce a second acceleration of the conveyor tray in an opposite direction, the first acceleration being less in absolute value than the second acceleration. The first acceleration causes the conveyor tray to move in a forward direction from an original conveyor tray position while simultaneously moving the counterweight assembly in a rearward direction opposite the forward direction from the original counterweight assembly position, and a second acceleration greater than the first acceleration causes the conveyor tray to move in a rearward direction back to the original conveyor tray position while simultaneously moving the counterweight assembly in a forward direction to the original counterweight assembly position. The switching of the motor between the first and second modes is the result of a change in current supplied to the motor, which translates into a linear reciprocating motion of the conveyor tray and counterweight assembly. In one embodiment of the differential impulse conveyor of the present invention, the change in current to the motor that produces the first and second modes of operation is a change in frequency of the current.

[0007] In some embodiments of the differential impulse conveyor of the present invention, a current regulator may be used to regulate the current to the motor to rotate the motor at a first angular velocity to move the conveyor tray in a first direction with a first acceleration. The current regulator then regulates the current to rotate the electric motor at a second angular velocity greater than the first angular velocity to move the conveyor tray in a second direction opposite the first direction with a second acceleration faster (in absolute value) than the first acceleration until the conveyor tray is returned to its original conveyor tray position. The current regulator must be synchronized with the differential impulse movement cycle of the conveyor tray and counterweight assembly. That is, the current regulator must effect a regulation change in the current supplied to the drive motor just as the conveyor tray is in its forward most position, which is at the end of a first operating mode of the motor in which the conveyor tray is moved in a forward direction and the counterweight assembly is simultaneously moved in an opposite direction. The current regulator then transitions to a second mode to generate a regulated current to cause an acceleration of the conveyor tray in the opposite direction. In one embodiment of the differential impulse conveyor of the present invention, the current regulator must switch between the first and second modes just as the conveyor tray is in its forward-most position and must switch from the second mode back to the first mode when the conveyor tray is in its rearward-most position. In another embodiment of the differential impulse conveyor of the present invention, the current regulator may switch between the first and second modes before the conveyor tray reaches its forward-most position and may switch from the second mode back to the first mode before the conveyor tray reaches its rearward-most position. This is a mechanical adjustment similar to spark advance that can be used to optimize the performance of an internal combustion engine that sparks ignites a combustible mixture received in a cylinder.Just as an ignition advance that can vary depending on the speed of the motor optimizes the performance of an internal combustion engine at a given speed, the advance applied to the time that a current regulator that regulates and supplies current to an embodiment of a differential impulse conveyor of the present invention switches from a first mode to a second mode or back to the first mode can be optimized to provide favorable behavior and efficient movement of items moved on the differential impulse conveyor for a given speed setting. This advance can be optimized to account for the delay or lag between the time that a change is made to the electric motor that powers the movement of the conveyor tray and counterweight assembly of an embodiment of a differential impulse conveyor of the present invention and the time that such a change begins to affect the characteristics of the movement of the conveyor tray and counterweight assembly.

[0008] Although the embodiment of the differential impulse conveyor of the present invention shown in the accompanying drawings shows detectable markers located on the outer surface of the first rotary-to-linear reciprocating motion converter, these markers may be located on another moving component of the differential impulse conveyor, such as the second rotary-to-linear motion converter, the counterweight assembly or the conveyor tray. The movement of the differential impulse conveyor system of the present invention may be controlled by a sensor that detects the position of the conveyor tray by using detectable markers located on the moving components of the conveyor system. The detectable markers may be located on the moving components and may be detected by a sensor, for example, when the conveyor tray reaches an optimal position, where the sensor detects the detectable marker, and the sensor generates and transmits a signal that transitions the current regulator to the second mode and adjusts the current to cause a greater acceleration (in absolute value) of the conveyor tray in the opposite direction. A row or series of detectable markers may be used to cause the sensor to continue to generate and transmit a signal to the current regulator to keep the current regulator in the second mode. When the end of the row or series of detectable markers passes the sensor, the sensor no longer detects the detectable markers and stops generating and sending signals to the current regulator, thereby causing the current regulator to return to the first mode, so that the conveyor tray begins to slow down and then reverse direction, again moving in the first direction at the first acceleration.

[0009] In one embodiment of the differential impulse conveyor of the present invention, the detectable markers are arranged in a row on the conveyor tray, and the sensor is positioned proximate to the conveyor tray to detect the row (or absence) of the detectable markers when the detectable markers are located near (or remote) from the sensor. In one embodiment of the differential impulse conveyor of the present invention, the detectable markers are arranged in a row on the counterweight assembly, and the sensor is positioned proximate to the counterweight assembly to detect the row (or absence) of the detectable markers when the detectable markers are located near (or remote) from the sensor. In one embodiment of the differential impulse conveyor of the present invention, the detectable markers are arranged in a series on an outer surface of the first rotary-linear reciprocating motion converter, and the sensor is positioned proximate to the first rotary-linear reciprocating motion converter to detect the row (or absence) of the detectable markers on the first rotary-linear reciprocating motion converter when the row of markers is located near (or remote) from the sensor. In one embodiment of the differential impulse conveyor of the present invention, the detectable markers are disposed in a series on an outer surface of the second rotary-to-linear reciprocating converter, and a sensor is disposed proximate to the second rotary-to-linear reciprocating converter to detect the series (or absence) of detectable markers on the second rotary-to-linear reciprocating converter when the series of markers is located near (or remote from) the sensor. The detectable markers may be disposed in a series or series on any of the movable components of the differential impulse conveyor embodiment, since the position of any movable component may serve as an indicator of the position of other movable components mechanically coupled thereto, and thus the detectable markers may be strategically placed on any movable component to indicate to the sensor the optimal time to transition the current regulator from the first mode to the second mode or from the second mode to the first mode. The row of detectable markers may be located, for example, but not limited to, on a conveyor tray, a counterweight assembly (if present), or a belt, and the series of detectable markers may be located, for example, but not limited to, on a rotating component of one of the first rotary-to-linear reciprocating motion converters or the like.

[0010] One advantage of some embodiments of the present invention differential impulse conveyor having sensors and detectable markers is that the current supplied to the electric motor can be "toggled" between a first mode where the current to the motor has a first frequency that places the motor and the conveyor driven by the motor in a first mode, and a second mode where the current to the motor has a second frequency that places the motor and the conveyor driven by the motor in a second mode. Sensors (e.g., optical, magnetic or electronic sensors) have parts and components that do not wear out and are unlikely to fail or require maintenance.

[0011] The sensor detects the row or string of detectable markers, and the sensor then generates a signal to a current regulator to adjust the current supplied to the motor to transition the operation of the conveyor from the first mode to the second mode. These types of drives can use a current regulator to vary the speed of rotation of the output shaft of the motor. Alternatively, a servo type motor can be used to control the change in speed from the first mode to the second mode and from the second mode back to the first mode. Servo type motors can be less efficient and more expensive than AC motors or permanent magnet motors, for example, where the sensor / markers are simply used to toggle a simple inverter to create the change in rotation speed. In one embodiment of the differential impulse conveyor of the present invention, the motor may be an Allen Bradley 525 model or a Yaskawa.

[0012] In one embodiment of the differential impulse conveyor of the present invention, the center of gravity of the counterweight assembly can be adjusted so that it coincides with the center of gravity of the conveyor tray. The center of gravity of the conveyor tray or counterweight assembly is the point at which the weight of the conveyor tray or counterweight assembly can be considered to act. The center of gravity is sometimes called the center of mass. This alignment of the centers of gravity of these two counter-moving objects (the conveyor tray and the counterweight assembly) reduces or eliminates impulse moments that would otherwise occur whenever the counterweight assembly and the conveyor tray are accelerated or decelerated in opposite directions by the action of the electric motor acting through the rotating output shaft. In one embodiment of the differential impulse conveyor of the present invention, the center of gravity of the conveyor tray and / or counterweight assembly can be altered by adding or removing, and placing and fixing removable weights thereon to bring the center of gravity and / or center of mass of the conveyor tray and / or counterweight assembly into alignment with the center of gravity and / or center of mass of the conveyor tray. This configuration reduces strength and durability requirements for the support structure on which the first rotary-linear reciprocating motion converter, the second rotary-linear differential motion converter and the motor of the differential impulse conveyor are supported, and reduces wear and tear on the structural elements of the differential impulse conveyor, which may result in reduced maintenance. Another advantage of using the first rotary-linear reciprocating motion converter to move the conveyor tray and, if present, the second rotary-linear reciprocating motion converter to move the counterweight assembly is that there is no raising and lowering of either the converter tray or the counterweight assembly because there are no pivoting support legs disposed between the conveyor tray or counterweight assembly and the facility floor (or other support structure).

[0013] One advantage of some embodiments of the differential impulse conveyor of the present invention is that the reduction or elimination of impulse moments achieved by adjusting the center of gravity and / or center of mass of the conveyor tray and / or counterweight assembly allows the differential impulse conveyor components to be supported by less robust structures that are less expensive to manufacture and assemble. Additionally, the less robust structures required allow for more thorough cleaning around and under the conveyor components because they require less footprint and mechanical bulk.

[0014] Another advantage of some embodiments of the differential impulse conveyor of the present invention is that it can use conventional motors powered by standard alternating current (AC). This is advantageous because it reduces the cost of the conveyor compared to conveyors that may use more expensive servo motors. In some embodiments, permanent magnet motors are also used, which improves efficiency and size compared to standard AC motors, and also significantly reduces the cost and complexity of servo motors. [Brief description of the drawings]

[0015] [Figure 1] 1 is an elevational view of a prior art differential impulse conveyor system having a conventional floor supported conveyor drive system. [Diagram 2] 1 is an elevational view of an embodiment of a differential impulse conveyor system of the present invention; [Diagram 3] FIG. 3 is a perspective view of a trough of a counterweight assembly of the embodiment of the differential impulse conveyor system of FIG. [Figure 4] FIG. 4 is an elevational view of the counterweight assembly of FIG. [Diagram 5] A top view of one of a set of optically detectable, magnetically detectable, and electronically detectable transponders and a proximity sensor configuration coupled to the outer surface of the rotary-to-linear reciprocating motion converter of the differential impulse conveyor embodiment of Figure 2. [Figure 6]FIG. 2 is a diagram of a current regulator control system for an embodiment of a differential impulse conveyor system of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Figure 1 is an elevational view of a prior art differential impulse conveyor system 111 having a conventional floor supported conveyor drive system 109. The prior art differential impulse system 111 of Figure 1 further comprises a conveyor tray 12 having a first end 14, a second end 16, and a trough 18 within the conveyor tray 12 for receiving items (not shown) from the first end 14 and transporting them to the second end 16 where they are discharged to a downstream station 13, such as a seasoning station where seasonings or other flavorings are added in a predetermined weight percentage amount. The conveyor 12 is moved horizontally back and forth as indicated by double arrow 20 by the floor supported conveyor drive system 109.

[0017] The floor supported conveyor drive system 109 of the prior art differential impulse conveyor system 111 of Figure 1 creates an amount of floor space 110A that is very difficult to access and therefore very difficult to clean and sanitize, as well as the adjacent floor space 110B below the downstream station 13. The limited accessibility caused by the conventional floor supported conveyor drive system creates problems when the conveyor system 111 is used to transport food products. The prior art differential impulse system 111 also includes a pivot support 15 that raises and lowers the conveyor tray 12 with each cycle as the pivot support 15 moves as shown by arrow 17.

[0018] Figure 2 is an elevational view of an embodiment of a differential impulse conveyor system 10 of the present invention. The embodiment of the differential impulse conveyor 10 of Figure 2 includes an elongated conveyor tray 12 having a first end 14, a second end 16, and a trough 18 (not shown) within the conveyor tray 12 for supporting an article or item (not shown) to be moved using the differential impulse conveyor 10, the conveyor tray 12 being linearly reciprocable forward (towards the second end 16) and rearward (towards the first end 14) as indicated by a double-headed arrow 20 illustrated on the conveyor tray 12. The embodiment of the differential impulse conveyor 10 of Figure 2 further includes a counterweight assembly 22 that is linearly reciprocable rearward (towards the second end 16) and forward (towards the first end 14) as indicated by a double-headed arrow 34 illustrated on the counterweight assembly 22. The counterweight assembly 22 of FIG. 2 includes a weight 32 that is removably securable to the counterweight assembly 22. Adding or removing the removably securable weight 32 allows a user of an embodiment of the differential impulse conveyor 10 to adjust the center of gravity (not shown) and mass of the counterweight assembly 22. Adjusting the center of gravity and mass of the counterweight assembly 22 by removing or adding the weight 32 allows a user to minimize or eliminate impulse moments that occur periodically as a result of the opposing accelerations of the conveyor tray 12 and the counterweight assembly 22 during operation of the differential impulse conveyor 10, as discussed further below. The removably securable weight 32 may be secured to the counterweight assembly 22 using fasteners such as conventional screws, bolts, nuts, or clips (not shown), or by having prefabricated receptacles or pockets located in the counterweight assembly 22.

[0019] The embodiment of the differential impulse conveyor 10 of FIG. 2 further includes an electric motor 50 having a conductive cable 55 for conducting electrical current to the motor 50, which is fixed to a support structure 60 and coupled through a first belt 42 to a first rotary-to-linear reciprocating motion converter 40 which converts the rotary motion of the output shaft 52 into linear reciprocating motion for moving the conveyor tray 12. The motor 50 also drives and is coupled through a second belt 46 to a second rotary-to-linear reciprocating motion converter 44 which converts the rotary motion of the output shaft 52 into linear reciprocating motion for moving the counterweight 22 against the conveyor tray 10. In the embodiment of the differential impulse conveyor 10 of Figure 2, the motor 50 is coupled to the first rotary-linear reciprocating motion converter 40 through the first belt 42 and the second belt 46, and the motor 50 is coupled to the second rotary-linear reciprocating motion converter 44 through the first belt 42 and the second belt 46. However, in other embodiments, the motor 50 may be directly coupled to the first rotary-linear reciprocating motion converter 40 and similarly the second rotary-linear reciprocating motion converter 44, or the motor 50 may be coupled to the first rotary-linear reciprocating motion converter 40 and the second rotary-linear reciprocating motion converter 44 through other arrangements, such as belts, chains, or gears.

[0020] The first rotary-to-linear reciprocating converter 40 of FIG. 2 has an exterior surface 41 to which a row or series of a plurality of detectable markers 69 are affixed. The row or series of detectable markers 69 is shown disposed on the exterior surface 41 of the first rotary-to-linear reciprocating converter 40 so as to extend approximately one-half of the circumference of the exterior surface 41 of the first rotary-to-linear reciprocating converter 40. A sensor 58 is disposed proximate the exterior surface 41 of the first rotary-to-linear reciprocating converter 40 to detect the detectable markers 69 when the motor 50 operates to rotate the first rotary-to-linear reciprocating converter 40 relative to the sensor 58. The sensor 58 generates a signal 59 to a current regulator (not shown in FIG. 2 ), which will be discussed in more detail herein below. The signal 59 generated by the sensor 58 may be transmitted to the current regulator (not shown) in some embodiments by, for example, but not limited to, a conductive wire, a fiber optic cable, or wirelessly.

[0021] A first rotary-to-linear reciprocating motion converter 40 is coupled between the motor 50 and the conveyor tray 12, and a second rotary-to-linear reciprocating motion converter 44 is coupled between the motor 50 and the counterweight assembly 22. The conveyor tray 12 includes a conveyor tray coupler 38 having a receptacle 39 through which the first rotary-to-linear reciprocating motion converter 40 is coupled to the conveyor tray 12. The counterweight assembly 22 includes a counterweight assembly coupler 138 having a receptacle 139 through which the second rotary-to-linear reciprocating motion converter 44 is coupled to the counterweight assembly 22.

[0022] The first rotary-to-linear reciprocating motion converter 40 and the second rotary-to-linear reciprocating motion converter 44 operate 180 degrees (3.14 radians) out of phase with each other, such that the linear reciprocating motion of the conveyor tray 12 and the opposing linear reciprocating motion of the counterweight assembly 22 are maintained in a reciprocal relationship to balance the impulse moments that arise when these components are accelerated by the operation of the motor 50. In other words, when the conveyor tray 12 is accelerated by the motor 50 toward the second end 16 of the conveyor tray 12, the counterweight assembly 22 is accelerated toward the first end 14 of the conveyor tray 12, and when the conveyor tray 12 is accelerated by the motor 50 toward the first end 14 of the conveyor tray 12 back to its original position, the counterweight assembly 22 is accelerated toward the second end 16 of the conveyor tray 12 back to its original position. This configuration balances the forces applied to the conveyor tray 12 and the counterweight assembly 22 by the motor 50, the first rotary-to-linear reciprocating converter 40 and the second rotary-to-linear reciprocating converter 44, respectively. Removably fixable weights 32 on the counterweight assembly 22 can be added or removed to fine-tune the balancing of the counterpulse moments between these reciprocating components of the differential impulse conveyor 10. Alternatively, the removably fixable weights 32 may be placed on the conveyor tray 12, or the removably fixable weights 32 may be placed on the conveyor tray 12 in addition to the counterweight assembly 22.

[0023] The motor 50, the first and second rotary-linear reciprocating motion converters 40 and 44, and the components of the differential impulse conveyor 10 supported by the first and / or second rotary-linear reciprocating motion converters 40 and 44 are supported by a structural support 60, which is in turn supported above a support surface or floor 99 by a proximal support 77 and a distal support 75. The proximal support 77 may be secured to the floor 99 by a proximal flange 78, and the distal support 75 may be secured to the floor 99 by a distal flange 76. By balancing the center of gravity and / or center of mass of the conveyor tray 12 and the counterweight assembly 22, the amount of force cyclically applied to the proximal support 77 and proximal flange 78 and the distal support 75 and distal flange 76 during operation of the differential impulse conveyor 10 can be dramatically reduced or eliminated, and the torque cyclically applied to the connection 80 between the proximal support 77 and the support structure 60 and the connection 79 between the distal support 75 and the support structure 60 is also reduced or eliminated.

[0024] 2, the differential impulse conveyor 10 may be used to receive a stream of articles 82 discharged from a distal end 81 of a feed conveyor 83 onto a first end 14 of a conveyor tray 12, transport the stream of articles 82 to a second end 16 of the conveyor tray 12, and discharge the stream of articles 82 onto a discharge conveyor 92. The differential impulse conveyor 10 may be used to transport the stream of articles 82 to a process or station such as, for example, but not limited to, a seasoning station where flavorings are added to the articles 82, a bagger where the articles 82 are bagged or packaged, a weighing device, or to any of a number of other processes or stations within a facility housing the differential impulse conveyor 10.

[0025] The differential impulse conveyor 10 of Figure 2 further includes a counterweight assembly linear bearing 48 that supports and allows for linear reciprocating motion of the counterweight assembly 22 as it is reciprocated by operation of the motor 50. The differential impulse conveyor 10 of Figure 2 further includes a conveyor tray linear bearing 73 that supports and allows for linear reciprocating motion of the conveyor tray 12 as it is reciprocated in opposition to the counterweight assembly 22 by operation of the same motor 50. The linear bearing 48 appears in Figure 2 to be very similar to the first rotary-to-linear reciprocating motion converter 40 and the second rotary-to-linear reciprocating motion converter 44. This similarity is because the first rotary-to-linear reciprocating motion converter 40 and the second rotary-to-linear reciprocating motion converter 44 are structurally similar to the linear bearing 48, with the difference being that the dimensions of the components of the linear bearing 48 are such that the range of motion of the counterweight assembly 22 is insufficient to allow the linear bearing 48 to reach its maximum range of motion in either direction of reciprocation, thereby preventing the linear bearing 48 from jamming or binding at its maximum range of motion. This adaptation of what is otherwise constructed as the rotary-to-linear reciprocating motion converter of U.S. Pat. No. 10,131,503 can be further understood by considering U.S. Pat. No. 9,879,179. In a preferred embodiment, a single electric motor 50 is connected and timed to the first rotary-to-linear reciprocating motion converter 40 and the second rotary-to-linear reciprocating motion converter 44 using timing belts. However, in another embodiment of the invention, two separate motors 50 are provided, one for driving the first rotary-to-linear reciprocating motion converter 40 which in turn drives the conveyor tray 12, and the other for driving the second rotary-to-linear reciprocating motion converter 44 which in turn drives the counterweight assembly 22 (if present).Using a common current regulator to drive the two motors allows for timing of one motor 50 relative to the other motor 50, which in turn provides timing for the counterweight assembly 22 and the conveyor tray 12. While the counterweight assembly 22 reduces stress on components of the conveyor system 111 embodiments of the present invention, some embodiments do not include a counterweight assembly 22, and in other embodiments, the counterweight assembly 22 is of a type other than that disclosed herein.

[0026] FIG. 3 is a perspective view of the counterweight assembly 22 of the embodiment of the differential impulse conveyor 10 of FIG. 2. The floor 33 of the counterweight assembly 30 is disposed between the first and second side panels 30A, 30B of the counterweight assembly 22. The floor 33, the first and second side panels 30A, 30B together form a trough within the counterweight assembly 22 for movably receiving at least a portion of the conveyor tray 12 therein. An opening 31 in the floor 33 of the counterweight assembly 22 accommodates a first rotary-to-linear reciprocating motion converter 40 (not shown in FIG. 3, see FIG. 2) disposed between the motor 50 and the conveyor tray 12. The opening 31 is elongated in the direction of reciprocating motion of the counterweight assembly 22 to accommodate the reciprocating motion of the counterweight assembly 22 relative to the fixed (but rotating) first rotary-to-linear reciprocating motion converter 40 that reciprocates the conveyor tray 12.

[0027] Figure 4 is an elevational view of the counterweight assembly 22 of Figure 3, showing the counterweight coupler 38 on the counterweight assembly 22, which has a receptacle 139 therein for engaging the first rotary-to-linear reciprocating motion converter 44 (not shown in Figure 4, see Figure 2). The optional removably securable weight 32 (see Figure 2) has been removed from the counterweight assembly 22 of Figure 4 for clarity. The extent 37 of the opening 31 in the floor 33 shown in Figure 3 is indicated by a double arrow on the second side panel 30B of Figure 4.

[0028] 5 is a plan view of a configuration of a sensor 58, such as one of a set of a plurality of optically, magnetically, and electronically detectable markers 69 coupled to an exterior surface 41 of the first rotary-to-linear reciprocating motion converter 40. The sensor 58 is positioned proximate to the first rotary-to-linear reciprocating motion converter 40 to detect the presence of the markers 69 as the first rotary-to-linear reciprocating motion converter 40 rotates in the direction of arrow 63. The sensor 58 generates a signal 102 to a current regulator 100 that changes the frequency of the current 55 supplied to the motor 50. For example, the current 55 supplied to the motor 50 by the current regulator 100 is provided to operate the motor 50 in a first mode when the marker 69 is proximate to the sensor 58 and a signal 102 (shown in FIG. 2) is generated by the sensor 58 and sent to the current regulator 100. Current 55 (see FIG. 2) supplied to motor 50 by current regulator 100 may be provided to operate motor 50 in a second mode when detectable marker 69 is not in close proximity (as occurs by first rotary-to-linear reciprocating converter 40 continuing to rotate in the direction of arrow 63) and signal 102 is no longer being generated and sent to current regulator 100. In the embodiment of the current frequency control system shown in FIG. 5, detectable marker 69 is located approximately one-half (180 degrees or 3.14 radians) of the circumference of exterior surface 41 of first rotary-to-linear reciprocating converter 40, thereby causing a current having a frequency that switches between the first and second modes to produce a "slow forward, fast backward" motion of conveyor tray 12 (not shown in FIG. 5) that moves articles along conveyor tray 12.

[0029] FIG. 6 is a diagram of a current regulation control system that can be used to control adjustments made to the current provided to the electric motor 50. With respect to the current frequency control system shown in FIG. 5, it can be said that the absence of the signal 102 generated by the sensor 58 (when the detectable marker 69 is not in proximity to the sensor 58) and sent to the current regulator 100 is in fact a second signal, in which case the second signal is a non-signal that causes the current regulator 100 to switch to the second mode. Alternatively, in another embodiment of the differential impulse conveyor 10 of the present invention, the current frequency control system may sense two different rows or series of detectable markers 69, each row or series being of a different type of detectable marker 69, each causing a different signal to be generated by the sensor 58. This (these) signals 102 are sent to the current regulator 100, with the first signal 102 corresponding to operation of the motor 50 in a first mode and the second signal (not shown) corresponding to operation of the motor 50 in a second mode.

[0030] A current 105 from a current source 106 is provided to a current regulator 100. When a detectable marker 69 is detected proximate to the sensor 58, a signal 102 is generated by the sensor 58 and received by the current regulator 100, and the regulated output current 55 to the motor 50 is at a frequency that causes the motor 50 to operate in a first mode. When a detectable marker 69 is not detected proximate to the sensor 58 (or, alternatively, a second type of detectable marker is detected proximate to the sensor 58), a signal 102 is not generated by the sensor 58 and is not received by the current regulator 100 (or, alternatively, a second signal different from the first signal is generated by the sensor 58 and received by the current regulator 100), and the regulated output current 55 to the motor 50 is at a frequency that causes the motor 50 to operate in a second mode. If the current adjustment is a frequency adjustment, then when a first signal 102 generated by the sensor 58 is received by the current regulator 100, the regulated output current 55 to the motor 50 will be at a frequency that causes the motor 50 to operate in a first mode, and when no signal 102 is generated by the sensor 58 and received by the current regulator 100 (or alternatively, a second signal different from the first signal is generated by the sensor 58 and received by the current regulator 100), the regulated output current 55 to the motor 50 will be at a frequency that causes the motor 50 to operate in a second mode.

[0031] The terms used in this application are merely for the purpose of describing particular embodiments and are not intended to limit the invention. In this application, the singular and the aforesaid are intended to include the plural as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising", when used herein, indicate the presence of stated features, integers, steps, operations, elements, components, and / or groups, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. The terms "preferably", "preferred", "preferred", "optionally", "may" and similar terms are used to indicate that the mentioned element, state or step is an optional (but not required) feature of the invention.

[0032] The corresponding structures, materials, acts, and equivalents of all means-plus-function or step-plus-function elements in the following claims are intended to include any structures, materials, or acts for performing that function in combination with elements recited in other claims that are specifically claimed. The description of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or to limit the invention to the disclosed form. Numerous modifications and variations will become apparent to those skilled in the art without departing from the scope and spirit of the invention. The embodiments have been selected and described in order to best explain the principles and practical applications of the invention and to enable others skilled in the art to understand the invention in various embodiments with various modifications as suited to the particular applications contemplated.

Claims

1. A differential impulse conveyor, comprising: an elongated conveyor tray movable in a forward direction at a first acceleration and in a rearward direction opposite the forward direction at a second acceleration greater than the first acceleration to cyclically move articles along the tray in the forward direction, the tray having a first end, a second end, a trough within the tray for transporting articles, and a conveyor drive coupler; an electric motor having a rotary output shaft; a first rotary-to-linear reciprocating motion converter coupled between the rotary output shaft of the motor and the conveyor drive coupler; Equipped with Operation of the motor causes the conveyor tray to move in the forward direction; Continuing to operate the motor causes the conveyor tray to reverse direction and move in the rearward direction; The differential impulse conveyor is a current regulator electrically coupled to the motor to regulate an input current source, the current regulator having a first mode in which an output current to the motor causes the motor to operate at a first speed to move the conveyor tray in the forward direction, and a second mode in which an output current to the motor causes the motor to operate at a second speed greater than the first speed to move the conveyor tray in the rearward direction; a plurality of markers fixed to a movable component of the differential impulse conveyor; a sensor disposed proximate to the movable component for sensing movement of the plurality of markers, the sensor generating a signal to the current regulator to switch between the first mode and the second mode when the sensor detects one or more of the plurality of markers approaching the sensor; A differential impulse conveyor comprising:

2. 2. The differential impulse conveyor of claim 1, wherein said motor is a variable frequency drive motor.

3. 3. The differential impulse conveyor of claim 2, wherein the sensor is a position sensor for detecting a position of the conveyor tray; the position sensor detects when the conveyor tray reaches a predetermined forward position of the conveyor tray and generates a signal to switch the current regulator from the first mode to the second mode; The position sensor detects when the conveyor tray reaches a predetermined rear position of the conveyor tray and generates a signal to switch the current regulator from the second mode to the first mode.

4. 4. The differential impulse conveyor of claim 3, wherein the position sensor comprises one of a mechanical detector, an optical detector, a magnetic detector, and an electronic detector, and one of a plurality of mechanical markers, optical markers, magnetic markers, and electronic markers disposed on a moving component of the differential impulse conveyor.

5. one of the plurality of mechanical markers, optical markers, magnetic markers, and electronic markers is disposed on an exterior surface of one of the exterior surfaces of the first rotary-linear reciprocating motion converter and the second rotary-linear reciprocating motion converter; 5. The differential impulse conveyor of claim 4, wherein the one of the mechanical, optical, magnetic and electronic detectors is positioned proximate to the one of the outer surfaces of the first rotary-linear reciprocating converter and the second rotary-linear reciprocating converter that is proximate to the one of the mechanical, optical, magnetic and electronic marker.

6. one of the plurality of optical markers, magnetic markers, and electronic markers is a plurality of magnetic markers fixed to an outer surface of one of the first rotary-linear reciprocating motion converter and the second rotary-linear reciprocating motion converter; 6. The differential impulse conveyor of claim 5, wherein the one of the mechanical, optical, magnetic and electronic detectors is a magnetic detector.

7. A counterweight assembly having a first side, a second side, a trough between the first side and the second side for receiving at least a portion of the conveyor tray, and a counterweight drive coupler; a second rotary-to-linear reciprocating motion converter coupled between the rotary output shaft of the motor and the counterweight drive coupler; Further equipped with Operation of the motor causes the conveyor tray to move in the forward direction and simultaneously causes the counterweight assembly to move in the rearward direction; 2. The differential impulse conveyor of claim 1, wherein continued operation of said motor causes said conveyor tray to reverse direction and move in said rearward direction while simultaneously moving said counterweight assembly in said forward direction.

8. The method of claim 7, further comprising: providing a conveyor drive coupler for driving said conveyor to said conveyor; a linear bearing coupled to the bearing coupler to support the conveyor tray as it moves; 10. The differential impulse conveyor of claim 1 further comprising:

9. A differential impulse conveyor as described in claim 7, wherein in the first mode of the current regulating device, an output current to the motor causes the motor to operate and move the counterweight assembly in the rearward direction, and in the second mode of the current regulating device, an output current to the motor causes the motor to operate and move the counterweight assembly in the forward direction.

10. 8. The differential impulse conveyor of claim 7, further comprising a first support structure for supporting said motor, said first rotary-to-linear reciprocating motion converter and said second rotary-to-linear reciprocating motion converter; The first support structure includes at least one vertical support member for supporting the conveyor tray and the counterweight assembly above the floor.

11. 9. The differential impulse conveyor of claim 8, further comprising a second support structure for supporting a linear bearing coupled to said bearing coupler on said conveyor tray.

12. A differential impulse conveyor as described in claim 7, further comprising a plurality of weights removably secured to the counterweight assembly.

13. 8. The differential impulse conveyor of claim 7, wherein the rotary output shaft of the motor is coupled to the first rotary-to-linear reciprocating motion converter with one of a belt, a chain, and meshing gears.

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