MXPA00004931A - Electronically coupled multiple shaft drive system for vibrating equipment - Google Patents

Abstract

The control system is particularly usable with extended vibration conveyors and permits the installation of multiple vibratory drive units (18, 20) comprised of one or more vibratory modules. Each module comprises a motor (34, 42), one or more shafts (22, 24, 26) mounting eccentric weights (50, 52, 54, 56), and a shaft encoder device (58) monitoring the relative position of each shaft (22, 24, 26). One shaft, a master shaft, is driven continuously at a predetermined speed from which the actual relative positions of the shafts are compared. A control device (68) is programmed with the predetermined relative shaft positions and receives signals from the various encoder devices (58) indicative of the actual relative positions of the shafts (22, 24, 26) and causes one or more motor control devices to alter the speed of each motor (34, 42) until the actual relative position essentially matches the programmed relative position.

Description

SYSTEM. TRANSMISSION TO MULTIPLE ARROW, ELECTRONICALLY COUPLED FOR VIBRATORY EQUIPMENT DESCRIPTION OF THE INVENTION BACKGROUND OF THE INVENTION This invention relates to control systems for vibratory conveyors and more particularly, to an adaptive control system for use with vibratory systems having housings or surfaces of extended or extended length for the transportation and / or treatment of articles in which the vibratory force is controlled over the entire length of the housing or surface. There are a number of systems in which the movement that provides direction and / or speed to the material being transported by the conveyor is controlled. An example of such a system is described in Patent No. 5,615,763 of the U.S.A., assigned to the same assignee of the present invention. As described therein with respect to one of its embodiments, a pair of spaced arrows that rotate in opposite directions are operatively coupled to a conveyor channel mounted on a stationary base, through a plurality of insulator springs. The arrows have eccentrically mounted weights that are oriented such that the resultant force acting on the conveyor due to the rotation of the arrows and thus their associated weights goes through a maximum and a minimum in a sinusoidal manner. The direction of the resulting maximum force is dependent on the "relative phase angle" between the position of the rotating weights and a data plane. By varying the phase angle between the arrows, the direction or angle of attack of the resultant force can be changed so that the rate of transportation and likewise the direction of the material on the conveyor can be changed. The invention in the aforementioned patent addresses the problem of maintaining an angle. of predetermined phase to provide the desired angle of attack through an entire cycle of operation of the conveyor through the use of a control system. Such a control system continuously measures the actual relative placement of the weights, compares this with a programmed and predetermined weight setting and adjusts the speed of the motor by actuating one of the arrows until the actual placement of the weights corresponds to the programmed placement. With the use of such a control system, the angle of attack is maintained constant throughout the operating cycle of the conveyor. Although the described system works admirably for conveyors with standard and short lengths, many industries require extended or extended treatment lengths of the material during processing. For example, long vibratory conveyors are often desired for thermal transfer processing. When it is required to move material through such elongated lengths as, for example, stretches exceeding approximately 30 feet, the use of a single unit conveyor has so far been highly impractical. The conveyors of elongated length become heavy due, in part, to the strength required to withstand the significant stress imposed on the frame or frame of the conveyor by the vibratory system along its length. The size of the frame and the concomitant cost become prohibitive. To solve this problem, manufacturers of vibratory equipment have found it necessary to employ two or more conveyors mounted end to end or have some technique to move the material between separate conveyors. It is therefore a primary object of the present invention to provide a control system for a vibratory conveyor that allows the construction of a single unitary conveyor of elongated length. It is still another important object of the present invention to provide a control system for a vibratory conveyor that allows the tandem or one after the other arrangement of a plurality of rotating arrows and concentric weights to provide a single angle of attack over the entire length of an elongated unit conveyor. It is also another object of the present invention to provide a control system for tumbler or tomb vibratory conveyors of elongated lengths.

BRIEF SUMMARY OF THE INVENTION The objects of the invention set forth above are generally indicated by a vibratory control system according to the present invention. Such a system generates a resultant and periodic vibratory force from a plurality of separate actuator "modules" towards a unitary conveyor surface and is capable of maintaining or changing the resultant vibratory force during its operation. For the purposes of the description, vibratory "modules" are vibratory components typically comprised of a motor, one or more arrows driven by the motor, weight or eccentric weights mounted on the arrow or arrows and any monitoring or monitoring devices of the position of the arrow that may be associated with the arrows. In some instances, two modules are combined to form a "linear force output drive unit" which is used to provide a periodic resultant force to the conveyor. The system generally includes a stationary frame connected by a plurality of spring or elastic members to a unitary conveyor surface and a plurality of separate drive units, operatively connected to the conveyor surface and spaced along its length, each of the drive units comprising two modules having respective first and second arrows, spaced apart, driven by respective first and second motors. Eccentric weights are mounted on each of the arrows. One of the modules is a master or command module with the first motor driving the first, arrow at a programmed predetermined speed. A device encoding the position of the arrow is associated with the end of each arrow and continuously generates a feedback signal of the position of the arrow, indicative of the position of the eccentric weight on that associated arrow. A motion controller receives each of the feedback signals from the position of the arrow, compares each of the positions of the arrow with phase angles or predetermined relative positions of the arrows, and generates a control signal for each of the arrows. the arrows whose position has varied from the predetermined position. An engine speed controller is responsive or responsive to the control signal for adjusting the speed of each of the motors associated with the arrows whose actual relative position has varied until the actual relative position coincides with the predetermined relative position.

DETAILED DESCRIPTION OF THE DRAWINGS Figure 1 is a mixed scheme of a control system of the present invention in combination with a vibrating conveyor apparatus showing a side view of the apparatus with a single conveyor channel coupled to a pair of vibratory drive units spaced apart , each having two modules comprising a motor and one or more rotating arrows that mount eccentric weights monitored or supervised by encoder devices of the arrow; Figure 2 is a top view of the embodiment of Figure 1 showing the respective location of the eccentric weights and of the arrow actuator elements; Figure 3 is a schematic diagram showing the various control signals and communication between the motion controller, the encoders and the motors of the apparatus of Figure 1; Fig. 4 is a schematic and flow diagram of the apparatus of Fig. 1 depicting the various routines used to compare the predetermined relative position of an arrow of the master motor of the master module with the actual relative positions of the arrows of the slave or slave modules and changing the relative positions to coincide with the predetermined relative position; Figure 5 is a mixed scheme of a control system according to the present invention in combination with a tumbler or vibratory tomb apparatus shown in a side view, wherein the apparatus has a single tumbler housing operatively connected to three drive units vibratory, spaced, each comprising a pair of modules that have a single motor, a pair of rotating arrows with eccentric weights, and a monitoring device that encodes the arrow; Figure 6 is a sectional view taken along lines 6-6 of Figure 5; and Figure 7 is an enlarged view of one of the modules of Figure 5.

DETAILED DESCRIPTION OF THE PREFERRED MODALITY First reference is made to figures 1 and 2 which describe a conveyor system generally indicated by the numerical character 10. The system 10 comprises a conveyor and vibratory surface or channel 12, mounted to a stationary base 14 by a plurality of springs 16. A cut in the length of channel 12 is shown to connote its elongated length. The base 14 becomes immobile and is typically fixed to the floor of the area in which the apparatus 10 is used. The springs 16 serve only to isolate the channel 12 from the base 14 and do not directly operate to provide vibratory movement to the channel 12. frames 18 and 20 can be secured to the lower slide carriage of channel 12 as shown, or connected to the channel through plenum walls (not shown). Each frame 18 and 20 houses a vibratory drive unit that includes the motors, arrows, eccentric weights and gear that imparts a linear force vibratory output to the channel 12. Each drive or transmission unit is comprised of a pair of modules as defined before. It is contemplated that the number of drive units may be duplicated and used in larger numbers than the two shown for extremely long conveyors. Referring now to the actuator units within the frame 18, it can be seen that three arrows 22, 24 and 26 are mounted to have rotational movement within the frame 18. A pulley 28 is mounted on one end of the arrow 22 and is driven by of the band 30 by the pulley 32 of the motor 34. A second pulley 36 is mounted on the other end of the arrow 22 and is engaged by the band 38 to the pulley 40 mounted on one end of the arrow 28. Thus, the motor 30 drives both arrows 22 and 26 collectively with the aforementioned beats and weights and forms a first module. A second motor 42 has a pulley 44 coupled by the band 46 to a pulley 48 of the arrow 26. Again, the motor 24 together with the pulley 44 and the arrow 26 with the weights form a second module within the frame 18. The motors 34 and 42 are preferably secured to the lower slide of the channel 12. As better illustrated in FIG. 2, the arrows 22 and 26 have weights 50 and 52 mounted eccentrically intermediate the ends thereof. Although not required in all situations, the weights preferably have the same mass and angular orientation with respect to their associated arrows. A pair of eccentric weights 54 and 56 are mounted in a distance spaced relation on arrow 24. When a linear path is required, it is preferable that the total mass of weights 54 and 56 be approximately twice that of the individual masses of weights 50 and 52. However, it should be understood that a different weight structure may be employed to provide a different path distribution, such as an elliptical if desired. The various elements of the modules of the frame 20 generally have the same functional relationships as the elements described above in the frame 18. For clarity, such elements of the frame 20 are denoted by the same numbers followed by the letter "a". It is preferred that the eccentric weights in the frame 20 have the same angular orientation and mass as the weights in the counterpart of the frame 18. The theory of operation or operation of a vibratory conveyor of eccentric weight is explicitly described in Patent No. 5,064,053 of the USA, which is incorporated here by means of its reference for its explanation of the theory. Briefly, however, the system shown in Figures 1 and 2 operates under the principle of altering the direction of the resultant maximum force acting on the conveyor due to the centrifugal forces imparted by the rotating eccentric weights. The maximum of the resulting force goes between a maximum and a minimum sinusoidally. The direction of the resultant maximum force depends on the relative phase angle between the position of the rotating weights. For example, as seen in Figure 1, the arrows 22 and 26 with their respective weights 50 and 52, have an angle A measured between a radial line directed outwardly from the center of the respective rotary arrows, through the midpoint of the arrows. weights (or some other reference point selected on the arrow) and a data plane, eg. , a horizontal plane that passes through the respective arrows. At the same time, each of the weights 54 and 56 mounted on the arrow 24 has an angle B measured in a similar manner. The centrifugal force generated by each of the rotating weights will be directed outward along the respective radial lines. The direction and magnitude of the movement imparted to the conveyor at a certain moment is determined primarily by that resulting from the centrifugal forces of the rotating weights, which in turn depends on the relative position of the rotating eccentric weights with respect to each other. . For example, if at first given, the angles A and B have the same value, eg. , 135 ° in quadrant II, the magnitude of the resultant force would have a maximum in that direction. When turning 90 °, the angle A is now 225 °, while the angle B is 45 °, so the forces are placed in opposite directions and the resulting force is at a minimum. With an additional 90 ° rotation, the forces point again in the same direction, that is, at 315 ° in quadrant IV, and the resulting force is at a maximum. An additional 90 ° rotation returns the resulting force to a minimum. Thus, in any rotation of 360 ° the resulting force goes to the minimum and maximum values twice. By varying the relative positioning or the relative phase angle between the arrows, the direction or angle of attack of the resultant forces can be changed so that the rate of transportation (and also the direction of movement) of the material on the conveyor channel can be changed. . In the invention as illustrated in the circumstance of FIGS. 1 and 2, it is essential that each drive unit module provides the same angle of attack and the same magnitude of the resulting forces. Therefore, it is preferred that the counterpart arrows within the frame 20 have eccentric weights of the same mass and angular orientation as those within the frame 18. A control system to ensure maintenance of the proper phase angles between the various rotating arrows it is shown in figure 1, in which sensor or encoder devices of the arrow 58 are placed, adjacent to each arrow 22, 24 and 22a, 24a. It should be remembered that arrows 26 and 26a are respectively driven by arrows 22 and 22a through a pulley and belt arrangement and thus always rotate at the same speed and thereby have the same real relative positions at all times. Such encoding devices 58 are well known in the state of the art and are readily available, for example, from Danaher Controls of Gurnee, Illinois, as indicated in the Table of Parts below. Each encoder device 58 detects a particular point on an associated rotating arrow and provides a continuous signal indicative of the relative position of the associated arrow. This information is fed to a controller 60, which compares the received signals with predetermined values for relative positions programmed within the controller. The controller 60 may be, for example, a programmable computer with a program for driving the motors and / or changing the phase angles of the eccentric weights. When the controller 60 detects a deviation from the predetermined values, it causes one or more of the variable frequency drive units 62, as required, to adjust the speeds of an associated motor and the phase angles of the associated arrow to coincide with the default value (s) for the relative positions.

PARTS TABLE Reference is now made to Figures 3 and 4 to better describe the operation of the present invention. For clarity, the arrows 24 and 24a and their weights, pulleys and belts are not shown in Figure 3. Initially, the user programs the controller 60 as represented by the input arrow 62 with a desired angle of attack as represented by the relative phase angles or positions for the various arrows within the controller 60. Additionally, the master arrow is provided with a predetermined rotational speed. Thus, the controller 60 calculates the appropriate relative phase angle or the "predetermined relative position" for each arrow 26 and 22a and 26a. It should be noted that the predetermined relative position of arrow 22a will ordinarily be programmed to be the same as that of arrow 22 although in some situations this may not be true. In a perfect system, the actual relative positions of the various arrows would be completely coincident with the predetermined positions and maintained throughout the operating time. However, arrow speeds will vary from time to time due to many external influences. These minor changes can, over a period of time, greatly vary the relative real positions and thus influence the angle of attack to the detriment of the proper functioning of the conveyor system. The encoder devices 58, however, are continuously monitoring the rotating arrows and provide a "feedback signal of the arrow position" signal 66 to the motion controller 68 of the controller 60. The motion controller then reads the signals 66 in READ (READ) 69, compares the actual position or relative placement of the arrows using the predetermined speed of the master arrow, and determines in the comparison routine 70 whether the position of the arrow of the arrow associated with a particular signal 66 has the phase angle or predetermined relative position entered within the controller 60. If YES (YES), means that the true relative phase angle coincides with the relative phase angle, then an angular correction is required in the positioning or positioning of the arrow "slave", that is, arrows 26, 22a or 26a, to coincide with the predetermined relative phase angle between the f "master" 22 and the slave arrow. To effect this correction, a determination is made in the calculation 72 of the change in velocity necessary for the slave arrow in order to return it to the appropriate relative phase angle. A variable frequency drive 62 adjusts the speed of the appropriate slave motor, eg. , the motor 42, 34a, or 42a, to cause the associated arrow to rotate relative to the master arrow to reach the appropriate relative phase angle and thereafter be maintained at the same speed as the master arrow. The foregoing illustrates that the present invention may incorporate a multiplicity of drive units, each comprised of one or more vibratory modules. Unitary conveyors of considerable length can be constructed using a number of vibratory drive units as dictated by the length of the conveyor. This provides a solution to the problem posed by the need to have systems that transport and / or treat materials on long lengths of vibratory surfaces. Still another use of the present invention is in tumbler-type vibratory systems, mainly used to clean workpieces, separate workpieces from coatings, or treat workpieces in other ways through the vigorous tumbling action of the tumblers. work pieces, one against the other and / or means having certain processing characteristics such as abrasivity, for example, in a vibrating housing of the system. Such systems are well known in the state of the art. A system is described in Patent No. 5, 109,633 of the U.S. of Durnill assigned to the same assignee of the present invention, in which the system causes the places or sites on the surface of the tumbler housing to have a trajectory of elliptical movement thus providing a tumbling movement into the workpieces and means contained by the accommodation. Until today, such tumbler devices were limited in size due to mechanical constraints imposed by the components used to vibrate the housings containing the work pieces and the structure of the apparatus itself. Typically, a single vibratory drive unit with a pair of modules was used to provide the vibration characteristics necessary to effect proper and desired tumbling within the housing. Any additional vibratory unit, if engaged, was mechanically coupled together with the first drive unit to ensure that the drive units provided the same vibration characteristics to the housing. Figures 5, 6 and 7 are illustrative of a control system according to the present invention that provides an upper tumbler apparatus when used particularly in combination with the type of grave of the system described in the aforementioned patent. As best seen in the mixed scheme of Figure 5, a cylindrically shaped housing 74 is insulated from a base 76 through a plurality of springs 78. The housing 74, although illustrated as cylindrical, can have any arched configuration, particularly with respect to the bottom or bottom half, which is conductive towards the appropriate tumbler action. The vibration is provided by a plurality of vibratory drive units illustrated by dotted lines as modules A, B and C. It should be understood that the number of drive units that can be employed is greatly a function of the length of the housing 74 and of the materials that comprise the housing and the support infrastructure. Each drive unit A, B and C as shown, is comprised of two modules each having a motor, a pair of arrows driven by each motor with the distal ends of each arrow mounting an eccentric weight. For convenience, the motors, arrows and associated weights of the drive units A, B and C are distinguished from each other by letters consisting of sub-indices that coincide with the designation of the character letter of the drive unit in which the motors , arrows and weights are placed. For example, the motors 80a, 82a are in the unit A, while the motors 80b, 82b and the motors 80c, 82c are in the units B and C respectively, each motor of the units A, B and C is mounted between a pair of brackets 88 extending outwardly from the wall of the housing 74. The left and right arrows 81a-c, 83a-c of each motor 80a-c, 82a-c respectively mount eccentric weights 84a-c, 86a-c that they provide the centrifugal force when they rotate. The axes of the arrows 81a-c and 83a-c lie in planes that are substantially parallel to the longitudinal axis 110 of the housing 74 (as best seen in Figure 7). Therefore, the eccentric weights 84a-c and 86a-c rotate in planes that are substantially perpendicular to the longitudinal axis 110. Although not required in all situations, the eccentric weights in the various units preferably have the same mass. Figure 7 shows an enlarged drive A and illustrates that the eccentric weights 84a and 86a on the left side of their respective motors rotate coplanarly as they do the eccentric weights 84a and 86a on the right side of their respective motors. The same coplanar relation is involved between the left and right weights 84b, 86b and 84c, 86c. Moreover, each drive unit is inclined with respect to the vertical and inclined at an angle 90 shown between the brackets 88 and the shaft toward one end of the housing 74 for the reasons discussed below. Finally, as can best be seen in the side section of Figure 6, the weights 84a and 86a, while rotating in the same plane, also rotate in opposite directions represented by arrows 94 and 96. Again, the same counter-rotation ratio is keeps true for weights 84b, 86b and 84c, 86c. The theory of operation or operation of the vibratory system illustrated in Figures 5, 6 and 7 is described in detail in Patent No. 5,109,633 of the US. mentioned above (with particular reference to figures 30 and 31 thereof), in which a single module comprising the drive unit has a motor that drives a pair of spaced and counter-rotating arrows, each having eccentric weights thereof Mass mounted to rotate coplanarly. The arrows illustrated in Patent No. 5,109,633 of the US. they are mechanically coupled so that the arrows rotate at the same speed and thus maintain the same relative position as dictated by the single engine. The discussion of the theory of operation described in Patent No. 5,109,633 of the US. is identical to that of the present invention described in figures 5, 6 and 7 and is hereby incorporated by reference. Basically, however, the effect of the eccentric weights against rotation and spaced at a distance. which rotate in the same plane, is to produce points on the inner surface of the housing 74 to follow an elliptical path. The means contained by the housing 74 are forced to move or flow circumferentially through and upwardly scaling the bottom portion of the housing 74 and are thrown into the housing together with the workpieces being treated. The inclination of the weights as discussed above tends to cause the medium and the work pieces to move slowly in the direction of the inclination. Alternatively, although not shown here, the housing 74 may be inclined in the opposite direction, to cause the enclosed material to move in the direction of the inclination of the housing with the inclination of the weights acting to retard this movement. To record the problem of treatment environments in which the articles are preferably treated along long treatment lengths, where it may be desirable to use a vibrating housing and elongated tumbler, those of the prior art have resorted to a partial solution in which a first pair of counter-rotating weights are mechanically coupled to a second pair of eccentric versus rotational weights. This partial solution can be seen in Figure 29 of Patent No. 5,109,633 of the above-mentioned U.S.A. This structure, however, is very limited in its application, tending to much greater opportunities for mechanical failure and considerably adding to the complexity of the machinery. The Applicant, however, has determined that a control system in accordance with the present invention can be easily combined with the desired vibratory system for tumbling that solves the problem of the elongate vibratory housings. From the view of Figure 5, it can be seen that the elongated length of the housing 74 is again connoted by a break in its length. Each of the arrows 81a-c and 83a-c are monitored by encoding devices 100 that provide continuous inputs representing the actual relative position of the monitored arrows to a controller 98 incorporating variable frequency drives (as described above) to control the Engine speed 80a-c and 82a-c. As previously discussed with respect to Figures 3 and 4, the controller 98 compares this information to a predetermined relative position programmed within the controller 98 by the user's input device 102. A motor, for example, the motor 80a, which constitutes a module (the "master" module) can be considered the master motor that is driven continuously at a predetermined speed. When one or more of the other engines called "slave engines", that is, 80b-cu 82a-c, constituting the other respective modules (the "slave" modules), deviates from the relative position programmed as monitored by the respective arrow encoders 100 of the various slave modules, the controller 98 Increases or decreases the speed of rotation of the motor or slave motors identified and the associated arrows to make the arrows coincide with the relative positions programmed by the arrows identified. From this, it can be seen that the mechanical coupling is completely eliminated, even when the proper speed of all the motors / arrows is maintained at the programmed speed, so that the characteristic of the force applied to the housing is consistent throughout the full length of the accommodation. This allows the use of a unitary tumbler housing of the:It is considerably greater than previously possible without increasing the concomitance in the mechanical complexity and structural strength of the conveyor required with mechanically coupled vibratory devices. From the above discussion, it can be seen that the vibratory control system according to the present invention solves the significant problems of prior art systems, in particular where it is necessary to use a vibrating surface or housing of considerable length to treat or transport items. Modifications of the control system will become readily recognized to those of ordinary skill in the art, without departing from the scope of the invention as described in the appended claims.

Claims (15)

1. A vibrating conveyor system for generating a resultant periodic vibratory force towards a conveyor surface, said system maintains or changes the resulting vibratory force during its operation or operation and comprises: (a) a stationary frame connected by a plurality of spring members to a surface conveyor; (b) a plurality of vibratory drive units operatively connected to said surface and spaced along their length, each of the drive units includes two drive modules with each module having a motor driving at least one arrow with a weight eccentrically mounted therein, a first module of said modules is a master module with said motor thereof actuating its arrow at a predetermined speed and the rest of the modules being slave modules; (c) a device encoding the position of the arrow associated with each arrow of said modules, to continuously generate a feedback signal of the position of the arrow for the arrow of said module; (d) a motion controller programmed to receive predetermined relative positions of said arrows and includes: (i) means for receiving each of the feedback signals from the position of the arrow, determining a real relative position of said arrows, comparing each one of the positions of the arrows of the slave modules with said predetermined relative position, and generating a control signal for each of the arrows of the slave modules, whose position of the actual arrow has varied from said predetermined relative arrow position and (ii) an engine speed controller responsive to the control signal to adjust the speed of each of the motors of the slave modules, whose associated arrow has varied from said predetermined relative position, until the actual relative position of said Associated arrow matches the default relative position.

The system of claim 1, wherein said transportation surface transports in a direction substantially perpendicular to the arrows of the modules.

The system of claim 2, wherein each drive unit has a first module with a motor and first and second arrows, said first and second arrows are mechanically coupled so that said motor drives both arrows to essentially the same speed and a second module that drives a single arrow mounted between said first and second arrows.

4. The system of claim 3, including a multiplicity of drive units.

The system of claim 1, wherein said transportation surface has an arcuate configuration with a longitudinal axis extending in a direction substantially parallel to the arrows of the modules.

The system of claim 5, wherein each of said modules has a motor that drives a pair of arrows that mount eccentric weights with said arrows having axes in a plane substantially parallel to a longitudinal axis of the transportation surface.

The system of claim 6, wherein there is a multiplicity of drive units spaced along the transportation surface.

8. A vibratory system for conveying articles through the use of a periodic resultant vibratory force at a predetermined angle of attack applied to a transportation surface, comprising: (a) a stationary frame connected by a plurality of spring members to said transportation surface; (b) a plurality of vibratory drive units operably connected to said surface along its length, each of the drive units having first and second drive modules with each module having a motor that drives a first arrow that eccentrically mounted a weight, one of said modules in the system is a master module with its motor driving the associated arrow at a predetermined speed and the rest of said modules are slave modules, said arrows of said modules rotate in a plane substantially perpendicular to a direction of movement of articles on the transportation surface; (c) a device encoding the position of the arrow associated with each arrow of each module to continuously generate a feedback signal of the position of the arrow for said associated arrow; (d) a motion controller that includes: (i) means for receiving each of the feedback signals from the position of the arrow, comparing each actual relative position of said arrows of the slave modules with the predetermined relative position, and generating a control signal for each of the arrows of the slave modules, whose actual relative position of the arrow has varied from the predetermined relative position; and (ii) a motor speed controller responsive to the control signal to adjust the speed of each of the motors of the slave modules, whose associated arrow has a real relative position that has varied, until the actual relative position of said associated arrow essentially coincides with the predetermined relative position.

The system of claim 8, wherein said first module of each of the drive units has a second arrow mechanically coupled to said first arrow of the first module and driven at the same speed as the first arrow, arrows first and second of the first module assemble eccentric weights with a collective mass essentially equal to a mass of said eccentric weight mounted by the arrow of the second module.

10. The system of claim 9, including a multiplicity of drive units.

11. A system for the treatment of work pieces, vibratory, for the laying down and the transportation of the work pieces, in which an elongated arched surface defines a longitudinal axis that extends substantially in the direction of the elongation, said surface meeting isolated from a stationary base through a plurality of insulated springs, which system also comprises: (a) a plurality of vibratory drive units coupled to said arcuate structure, each unit having a pair of modules each having a motor and arrows rotationally extending with eccentrically mounted weights, said arrows rotate in a plane substantially parallel to said longitudinal axis and the weights are rotated in the same plane substantially, said vibratory actuating units imparting an elliptical trajectory to points on the arcuate surface, one of said system modules is a master module with its motor being the master motor that drives its arrow at a predetermined speed and the rest of said modules being slave modules; (b) a device encoding the position of the arrow, associated with each arrow of each module to continuously generate a feed-back signal from the position of the arrow for each of said arrows; (c) a motion controller programmed to receive predetermined relative positions for said arrows and includes: (i) means for receiving each of the feedback signals from the arrow position, comparing the actual relative positions of the arrows with the positions programmed ratios of the arrows, and generating a control signal for each of the arrows of the slave modules whose actual arrow position varies from the predetermined actual position; and (ii) a motor speed controller responsive to the control signal for adjusting the speed of each of the motors of the slave modules whose associated arrow has a real relative position different from the predetermined relative position and until the arrow associated has a real relative position that matches the default relative position.

The system of claim 11, wherein said arrows are inclined with respect to the longitudinal axis.

13. The system of claim 12, wherein the eccentric weights have essentially the same mass. The system of claim 13, wherein the arcuate surface is a portion of the inner surface of a cylinder and said longitudinal axis extends parallel to the central axis of the cylinder. The system of claim 11, which includes a multiplicity of drive units spaced along said surface.