Abstract:
An apparatus for advancing articles in a selected, approximately horizontal conveying direction, includes a plurality of side-by-side disposed table elements each having an upper, approximately horizontal article-supporting surface. The article-supporting surfaces together form an approximately horizontal conveying table. A first drive oscillates each table element parallel to its article-supporting surface in a motion having two motion components oriented in perpendicular, horizontal directions and a second drive vertically oscillates each table element. A first synchronizing arrangement synchronizes the horizontal oscillations in the direction of the two motion components and a second synchronizing arrangement synchronizes the vertical oscillations with the horizontal oscillations. A first adjusting arrangement adjusts the phase of the vertical oscillations with respect to the horizontal oscillations and a second adjusting arrangement individually adjusts an amplitude of the vertical oscillation of each table element.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of International Application PCT/CH98/00013 filed Jan. 15, 1998. 
     Further, this application claims the priority of Swiss Application No. 0179/97 filed Jan. 28, 1997, which is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     U.S. Pat. No. 3,174,613 describes a conveyor apparatus which includes a plurality of rolls, arranged in rows, between two spaced conveyor belts progressing in identical conveying directions. The axes of the rolls in each row are horizontal and are oriented parallel to one another. The rolls are driven either with the circulating speed of the conveyor belts or with a speed which is 1.4 times higher. The upper, common tangential plane of the rolls is coplanar with the upper face of the conveyor belts. The axes of the rolls of each row may be pivoted jointly about 45° from a basic position in which they are disposed perpendicularly to the advancing direction of the conveyor belts. In the outwardly pivoted position the rolls deliver articles, such as glass panes, to a transverse conveyor belt. 
     British Published Patent Application No. 2,259,900 describes a conveying apparatus with which articles may be conveyed in one of four selectable directions on an approximately horizontal table. The table is composed of a plurality of side-by-side arranged table elements which execute synchronously translatory oscillations in both directions parallel to the plane of the table. In addition, each table element is driven to oscillate vertically, and the vertical oscillations are synchronized with the horizontal oscillations. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to provide an improved apparatus of the above-outlined type which makes possible a simple adaptation to the conveying speed of the articles with a simple construction. 
     This object and others to become apparent as the specification progresses, are accomplished by the invention, according to which, briefly stated, the apparatus for advancing articles in a selected, approximately horizontal conveying direction, includes a plurality of side-by-side disposed table elements each having an upper, approximately horizontal article-supporting surface. The article-supporting surfaces together form an approximately horizontal conveying table. A first drive oscillates each table element parallel to its article-supporting surface in a motion having two motion components oriented in perpendicular, horizontal directions, and a second drive vertically oscillates each table element. A first synchronizing arrangement synchronizes the horizontal oscillations in the direction of the two motion components and a second synchronizing arrangement synchronizes the vertical oscillations with the horizontal oscillations. A first adjusting arrangement adjusts the phase of the vertical oscillations with respect to the horizontal oscillations and a second adjusting arrangement individually adjusts an amplitude of the vertical oscillation of each table element. 
     By providing that the phase of the vertical oscillation of each table element may be adjusted relative to the horizontal oscillations, the articles situated on each table element may be conveyed into an arbitrarily selected direction. By virtue of the individual adjustability of the amplitudes of the vertical oscillation, the conveying speed within the table may also be changed in a simple manner. By oscillating all the table elements in a horizontal plane by a common drive according to a further preferred embodiment, the transporting speed of all the table elements may be simultaneously altered in a simple manner over the entire table by changing the horizontal oscillating frequency or amplitude while maintaining the vertical oscillation amplitude the same. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic top plan view of a conveyor apparatus incorporating the invention. 
     FIG. 2 is an enlarged schematic top plan view of one part of the construction shown in FIG.  1 . 
     FIG. 3 is a schematic fragmentary sectional elevation of a preferred embodiment of the invention. 
     FIG. 4 is a fragmentary sectional elevation of a variant of FIG.  3 . 
     FIG. 4 a  is a fragmentary sectional elevation of another variant of FIG.  3 . 
     FIG. 5 is a symbolic top plan view, with diagrams, of the conveyor apparatus of the invention, illustrating the mode of operation. 
     FIG. 6 is a sectional elevational view of a further preferred embodiment of the invention. 
     FIG. 7 is an enlarged sectional view of a part of the structure shown in FIG.  6 . 
     FIG. 8 is a top plan view of the construction shown in FIG.  6 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 illustrates the apparatus symbolically in a top plan view as used in a packing machine. The apparatus includes a horizontal, square table  10  which is composed of a plurality of square table elements  11  situated in a close vicinity to one another. Each table element  11  has a top, article-supporting surface  11 ′. A conveyor belt  12  delivers rows  13  of products  14  to the table  10 . The products  14  are advanced in the direction x on the table  10  and are distributed in the direction y and, if required, turned to be loaded into packing containers  15  along the right-hand side table edge. The containers  15  are supplied by a separate conveyor  16  and are, subsequently to their being charged with products  14 , moved away for further wrapping. Each table element  11  can advance the article which it supports in any desired direction. In case a product  14  is supported by at least two table elements  11 , then, upon a suitable selection of the conveying direction, the product may be turned as illustrated in FIG.  2 . The outline of the table elements  11  may be, in the alternative, of other than the illustrated square shape: they may be rectangular, triangular or hexagonal. Other polygonal shapes may also be feasible; in such a case, however, the table elements  11  would not be uniform. 
     FIG. 3 shows a section of a part of a preferred embodiment. On a stand  20  two vertically oriented drive shafts  21  are rotatably and axially non-displaceably supported. One shaft  21  is driven by belt sprockets  22  and a toothed belt  23  from an rpm-regulated drive motor  24  which is controlled by a control device  49 . Respective guide members  25  are affixed to the upper end of each drive shaft  21 . On each guide member  25  a sled  26  is guided for displacement transversely to the axis of the shafts  21  and may be immobilized by means of screws  27  which project through slots  28  of the guide members  25 . The sleds  26  carry a respective eccentric pin  29  extending parallel to the shafts  21 . By releasing the sleds  26  by the screws  27  and by displacing them relative to the respective guide member  25 , the eccentricity a of the pins  29  may be adjusted. The pins  29  are supported in a joint, horizontal carrier plate  30  for rotation. To the lower end of each shaft  21  a respective flange  31  is secured which carries a further, non-adjustable eccentric pin  32 . The eccentricity of the pins  32  is offset by 90° relative to the eccentricity of the pins  29 . The pins  32  are rotatably supported in a coupling bar  33 . Both shafts  21  are connected to one another to rotate as a unit: When the motor  24  is running, the carrier plate  30  executes a circular motion in its plane, imparted by the left-hand pin  29 , and the circular motion is, in turn, imparted by the right-hand pin  29  to the right-hand shaft  21 . Further, to the shafts  21  a respective eccentric mass  34  is secured for compensating for the imbalance of the carrier plate  30 . 
     Each table element  11  is supported on the plate  30  by leaf springs  39  such that each table element  11  is vertically displaceable parallel to itself. A plunger  40  extends centrally from each table element  11  in a downward direction through respective openings provided in the carrier plate  30  and is provided with a tapered end  41 . 
     A respective servomotor or stepping motor  42  is secured to the machine frame  20  such that it is laterally offset from the axis of each respective plunger  40  at a distance which corresponds to the eccentricity a of the pins  29 . The motor  42  has a vertical output shaft  43  to which a cylindrical pin  44  is secured, having an axis which is inclined to the axis of the shaft  43 . A cylindrical shoe  45  is coaxially secured to the pin  44 . The shoe  45  has an oblique, planar top face  46  engaged by the terminus  41  of the plunger  40 . The angle which is formed by the surface  46  with a radial plane of the shoe  45  corresponds to the angle at which the axes of the shaft  43  and the pin  44  intersect. By rotating the shoe  45  relative to the pin  44  the inclination of the surface  46  relative to the horizontal may be set from 0° to the illustrated maximum inclination. Each motor  42  is individually controllable by a control device  48  so that the surfaces  46  may be individually set into a desired orientation. The controls  48 ,  49  are controlled by a joint control device  50 . The upper face of the table  10  may be covered by a thin, flexible sheet  47  made, for example, of polyurethane or another synthetic material which bridges over the clearances  48  between the table elements  11 . In this manner the risk of soiling is reduced. 
     In the description which follows, the operation of the above-described apparatus will be set forth. 
     The motor  24  rotates with a set, constant rpm, for example, 10-30 Hz, so that the table elements  11  execute, in their own plane, a circular motion having, for example, a radius of 5 mm. Because of the inclination of the surfaces  46 , the table elements  11  also perform a periodic vertical motion having a stroke amplitude h of, for example, 1.8 mm. The frequency, the radius a and the stroke h are selected such that the downward acceleration of the table elements  11  at least in the region of the upper dead center of the stroke is greater than the gravitational acceleration so that the product  14  lifts off periodically from the respective table element  11 . Since the table element  11 , because of its circular motion, has moved away from under the floating product  14 , by the time the latter again lies on the table element  11 , it has been shifted relative thereto and thus has executed a translational motion on the table  10 . By rotating the shoe  45  about the axis of the shaft  43  the direction of motion may be selectively chosen: it may differ in different sectors of the table  10 . It is, for example, feasible to move the products  14  on the table  10  along a circular path. If one of the motors  42  rotates synchronously with the shafts  21 , the product  14  remains stationary on the respective table element  11  because in such a case no vertical oscillation occurs. The speed of the motion depends from the rpm of the motor  24 , the eccentricity a and the stroke amplitude h. When the rpm and/or the eccentricity a and/or the stroke amplitude h is increased, the speed increases. The stroke amplitude h, however, may be selected to be so small that the products  14  are not lifted off the upper surface of the table elements  11 . In such a case the frequency and the eccentricity a are so set that the products  14  slide on the upper face of the table elements  11  at least in phases, that is, during the downward acceleration of the elements  11 . During an upward acceleration, the frictional force between the table elements  11 , on the one hand, and the products  14 , on the other hand, is greater than for the downward acceleration so that in such a case a translational motion of the products  14  on the table  10  takes place. 
     FIG. 4 shows a variant for the actuation of the shoe  45 . In the embodiment shown in FIG. 4, the shoe  45  is a circular disk which is supported in its middle on a ball joint  51  which, in turn, is mounted on a column  52  secured to the machine frame  20 . On the periphery of the shoe  45 , at 90° apart, there are provided two further universal joints  53  (only one is visible), each of which is height-adjustable by a separate, linear stroke producing element  54 . The elements  54  which are pivotally secured to the machine frame  20 , may be, for example, stepping motors with threaded spindles or may be linear motors provided with resetting means. This variant has the advantage that not only the direction but also the extent of inclination of the surface  46 , that is, the stroke amplitude h may be individually adjusted for each table element  11 . In this manner, for the products  14  on the table  10  different speeds in different sectors may be predetermined. 
     Turning to FIG. 4 a,  departing from the structure of FIG. 4, as the carries plate  30  circulates in a horizontal plane, the shoe  45  is oscillated vertically. For this purpose, a sole, linear stroke producing component  54 ′ is provided which is secured to the machine frame  20  and which is driven to execute vertical strokes synchronously with the horizontal oscillation of the carries plate  30 . The stroke amplitude and the phase of motion with respect to the horizontal oscillation may be adjusted for the stroke producing component  54 ′. 
     FIG. 5 illustrates a mode of use of the above-described embodiments for dividing and grouping the products  14  delivered to the apparatus by the belt  12 . 
     The average advancing speed v x , on the table  10  in the conveying direction A of the belt  12  is greater than the belt speed. The products  14  are delivered in four columns  57  which are shifted laterally on the table  10  by an appropriate selection of the conveying direction of the table elements  11  to form table columns  58 . In each instance, to the right and the left of each such table column  58 , the conveying direction R of the table elements  11  has a component which is oriented towards such column  58 . At the right-hand edge of the table  10  the products  14  are grouped into two groups, each containing six fields  59 , formed by a respective table element  11 . The conveying direction of the table elements  11  which immediately surround the fields  59  is oriented radially toward these fields. The transporting velocity of the fields  59  is zero. As soon as a group  60  is complete, it is moved away for packaging, for example, by means of suction grippers. Between the left edge of the table  10  and the groups  60  to be formed, the rows  13  are moved in the x direction with propagating waves. At the respective desired position of the row  13  the table elements  11  convey the articles with the desired velocity in the x direction. The table elements  11  situated immediately to the right, convey the articles slower whereas each table element  11  to the left conveys the articles faster. In this manner it is feasible to hold the rows  13  on the table  10  in an aligned manner and to align them in case they are delivered unaligned by the conveyor belt  12 . The apparatus is preferably controlled by means of a non-illustrated optical recognition device disposed above the table  10 . 
     FIGS. 6,  7  and  8  illustrate a further embodiment of the invention. A separate drive  65  is mounted on the machine frame  20  for each table element  11 . A cross-sectionally square tube  66  having a planar bottom  67  is affixed centrally to, and extending downwardly from, each the table element  11 . The tube  66  is surrounded by a box-like carrier  68  having three mutually perpendicular walls  69  and being mounted on the machine frame  20 . A ferromagnetic armature  70  carrying a respective coil  71  is secured to each wall  69 . A respective plunger coil  72  affixed to the tube  66  or, as the case may be, to the bottom  67  thereof, extends into a cylindrical air gap  73  of the armature  70 . A screw  74  which is threaded coaxially into the armature  70  carries two biased compression springs  75  which are supported, on the one hand, on an extension  76  of the tube  66  at the bottom  67  and, on the other hand, by the underside of the screw head  77 . In this manner, each table element  11  is positioned in its central orientation. 
     An alternating current with a selected, identical frequency is applied to the three plunger coils  72 . The phase and the amplitude of the AC voltage is settable individually among the three coils  72 . If, for example, for both coils  72  having a horizontal axis  78  the amplitude is the same and the phase shift is 90°, the table element  11  executes a circular motion parallel to itself. The advancing direction and velocity of the products  14  may be set by adjusting the phase shift and the amplitude of the coil  72  having a vertical axis. In this embodiment, instead of a circular motion, an elliptical or a linear horizontal motion of the table element  11  may be achieved dependent on the phase shift and the amplitude relationship between the voltages applied to the coils  72  having a horizontal axis. Thus, in the embodiment according to FIGS. 6,  7  and  8  each table element  11  is horizontally and vertically oscillated by its own electromagnetic assembly composed of three electromagnets. 
     The three plunger coil assemblies  70 - 75  may be replaced by three linear motors with resetting means. Such an arrangement has the advantage that the oscillation amplitudes are independent from weight or whether a product  14  is present or not. This is particularly advantageous during the transfer of a product  14  from one table element  11  to another. 
     It will be understood that the above description of the present invention is susceptible to various modifications, changes and adaptations, and the same are intended to be comprehended within the meaning and range of equivalents of the appended claims.