TRANSPORT SYSTEM

Abstract: A system intended for the transport and storage of product carriers, comprising a plurality of elongated transport units, adapted to be connected to each other so as to form a transport network. The transport units comprise a frame (1a, 1b; 2a, 2b etc.) with carrier rollers (7) for the product carrier (9) and an elongated transporting screw (15) provided with driving members (17), the threads of which are adapted to cooperate with engagement members (43) provided at the bottom side of the product carrier in such a manner that upon operation of the screw (15) the product carrier (9) is advanced along the transport unit, the transporting screws (15) being driven in such a manner that they are always started and stopped in a predetermined position of the transporting screw. By means of a computer apparatus counting and registering the number of revolutions of the transporting screws a permanent and exact control of the position of each product carrier in the system is made possible. The engagement members (43) of the product carriers (9) may be formed by ridges, spaced mutually along the transporting screw with the same cross-sectional thread profile as the thread groove of the transporting screws, said rims each meshing with the transporting screw during the transport.

Description: Transport system. Systems for the transport and storage of products are previous¬ ly known, in which the products are moved to their destination along lines or pathways in a transport network, means being provided for guiding the product to be transported to its in- tended destination in the system. In certain systems the trans¬ port route is selected in response to data with which the pro¬ duct proper or a product carrier has been provided. Means may be provided. for mechanical, electrical or contact free sen¬ sing of said destination data and for controlling the trans- port means of the system in response hereof, so that the pro¬ duct is directed to its destination. It is known in such sys-. terns to provide means for delivering information that the pro¬ duct has arrived at the intended destination. The systems previously known which may operate according to various principles, do not in a simple manner allow a . perma¬ nent and exact information of where in the system the product is momentarily located during the transport process and, the¬ refore, they do not allow re-direction of the product in an arbitrary moment to a changed destination or to a parking po- sition when required. The known arrangements do not therefore allow occasional interferences in the transport work in a simple manner in order to give e.g., priority to a certain product type for an urgent order or to perform the necessary, changed dispositions upon damage or the like. An object of the present invention is to provide a transport system, in which the disadvantages mentioned above are re¬ moved. Another object of the invention is to provide a transport system, which is particularly adapted for control, monitoring _-' " __,KJ__^ ________ V ^o and programming by means of modern electronic equipment-. Further object of the invention is to provide a transport system, which is particularly adapted to be assembled from modules for the adaption to any particular use, whereby the manufacture of the components of system is rendered simplier and more economic. .Still another object of the invention, is to provide a tran ' port system, ±n ~ which a product or a product carrier can be easily removed manually from the transport lines and again replaced thereon wi hout the transport of other products in the system being disturbed. Other objects and advantages of the invention will appear from the following description and the accompanying drawing A transport system according to the present invention has the features stated in claim 1. Additional features of se¬ lected embodiments of the system are stated in the sub- claims. On the attached drawings there is known an embodiment of a transport system according to the invention as well as de- tails thereof. Fig. 1 shows in perspective a representative section of the transport system according to the embodiment Fig. 2 shows the same section as Fig. 1 but seen from above Fig. 3, 4 and 5 show a generally parallellipipedic product carrier for the transport system, seen from below, in longi tudinal section and from the short end side, respectively. Fig. 6, 7 and 8 show, seen from above, from the side and from the end, respectively, a portion of a frame included in the system. Fig. 9 shows in longitudinal section trans¬ porting screws included in the system. Fig. 10 is a side elevation of an arrangement for transferring transported products between different horizontal planes. Fig. 11 is a side elevation of a device for changing the direction of the product transported in both the vertical and the horizontal planes. Fig. 12, 13 and 14 shown from above, from below and from the side, respectively, a product carrier according to the invention and at the same time the support of the pro¬ duct carrier and its movement in the transport system. Figs. 15 to 21 show in a similar manner another embodiments of the product carrier. The section of the transport system of the invention shown in Fig. la comprises a frame, which includes a first pair of carrier beams.la, lb, on which a plurality of horizontally supported carrier rollers 7 for product carriers 9 are rota- tably mounted, and additional, similar pairs of carrier beams 2a, 2b, 3a, 3b, 4a, 4b and 5a, 5b with similar carrier rol- lers. The carrier beams are supported from a base or floor by means of legs 6. The various pairs of carrier beams with their carrier rollers form an equal number of generally hori¬ zontal transport lines for the product carriers 9. These car¬ riers are illustrated in Fig. 1 as being of box shape but they can be of any other desirable shape depending on the pro¬ duct to be transported. The transport lines can be intercon¬ nected mutually by means of a switching station 11 and a tur¬ ning station 13 in the manner described hereinbelow. During the advancement of the product carriers 9 on the car- rier rollers 7 of the carrier beams the product carrier is guided laterally by guide flanges 7a on the carrier rollers which flanger about against the external Jpngitudinal side of continuous rims 43, 45 located at the bottom side of the product carrier, against the bottom surface of which rims the carrier rollers are rolling, see Fig. 3 to 5. The number of carrier rollers per unit length of the carrier beams is such that each product carrier is always supported by at least three pairs of carrier rollers. For the advancement and the position identification of the product carriers there are provided between the carrier beams of each pair of beams special rotatable screws 15 in the thread grooves of which cams, ledges or the similar en¬ gagement members 43, 45, see Fig. 3 to 5, at the bottom of the product carriers, mesh. The cross-sectional profile of the thread grooves corresponds in shape and size with the cross-sectional profile at the rims 43 and 45. According to Fig. 1 the transporting screw 15 is common to the transport lines 2a, 2b and 5a, 5b. Threads are lacking along the por- tion of the transporting screw which passes a switching sta¬ tion 11 described more closely later. The screws are suppor¬ ted from the frame by means of special bearings, which are shown in more detail in Fig. 10 and they are driven by motor 17, which allow an exact determination of the number of revo lutions to be carried out by the motor in order to perform a certain transport operation and exact recording of the numbe of revolutions carried out by the motor. The transmission be ween the motor 17 and the screw 15 is performed by means of a non-skid belt, e.g., a toothed belt 19, and is arranged no to surpass in height at any portion -thereof the bottom surfac of the rims 43, 45 of the product carrier. In Fig. 1 there is also shown a station 21 with means for so called under-stacking (stacking from below) of product car¬ riers 9, comprising, i.a., arms 23 for clamping the lower- most product carrier in a stack of product carriers - in Fig. 1 a stack of two such carriers - and raising the stack at stacking and lowering the stack at the removal thereof by means of the transport system, all in a manner known per se in other connections. In Fig. 2 the main portion of the section according to Fig. is shown as seen from above. The switching unit 11 comprises a frame in the form of a horizontal, square framework 31 of carrier beams, which, however, is not provided with carrier rollers for the product carriers, as the carrier ' beams desc- ribed above , but are instead provided with ball-shaped carrier members 33 , one in each corner of the framework and one at each side of the transporting screws 15 belonging to one each of the transport lines connected to the switching station . The ends of the transporting screws connected to the switching sta¬ tion have their threads squarely terminated, and the ends of the threads are referenced 35 . The ball supports 33 support the product carrier at the same level as the rollers 7 of the transport lines and the distan- ce between the ball supports are equal to the distance between the rollers 7. The ball supports may also in a manner known per se consist of spherical balls , e . g. ,. steel balls mounted in ball retainers so that the balls may be rotated in all di¬ rections , which is known per se in other connections . The product carrier according to the embodiment illustrated in Fig . 3 to 5 comprises a parallellipipedic box of plastic material , e . g . polyethylene , with a bottom 41 formed with ridges rims or other engagement members 43 , 45 in the trans¬ verse and the longitudinal direction , respectively , the cross- section of which matches the cross-section of the thread groo¬ ves of the s crews 15 . The ridges 45 are located as near to the longitudinal s ides of the box as possible and the distance bet¬ ween the rims 43 are equal to the distance between the ridges 45 . The cross-section of the ridges is trapeziodal , with the large base located at the bottom of the box. The box 9 can be formed with apertures 47 forming carrying grips in the side walls . Fig . 3 to 5 show the position of the product carrier 9 when it is located centrally of the switching station 11 to which it has been advanced along any of the transport lines con¬ nected to the station . At this location the product carrier is supported only by the ball shaped support members 33 . The advancement to the station is performed by means of the screw 15 belonging to the transport line in the threads of which the ridges 43 or 45 engage during the transport . The transporting screws are rotatably supported in the manne illustrated in Fig. 8. On a cross beam 53 between the car¬ rier beams, e.g., the carrier beams la and lb, a support 51 is secured, which is plate shaped and projects upwardly thro a slot 61 between two sections 15a and 15b of the tubular screw 15. The support carriers a bearing shell 55 for a ball bearing 57. The external diameter of the bearing shell 55 is such that the bearing shell is completely located within the transporting screw. The bearing 57 encloses a bearing sleeve 59 on one section 15b of the transport roller, said bearing sleeve being supported by and secured to the inner wall of the tubular section 15b. The sleeve 59 has a central bore, which tightly encloses a stud 63 projecting from the adja¬ cent end of.the other screw section 15a and secured thereto, said stud being locked in respect of rotation to the sleeve 59 by means of a locking pin 65.- The transporting screws 15 may be rotatably supported in the manner illustrated in Fig. 9 at any location along its length as well as at its ends, and from Fig. 8 it is evident that the bearing device does not interfere into the interspace between the screw threads of the upper portion of the trans¬ porting screws cooperating with the lower rims 43, 45 of the product carriers, but the product carriers can be advanced unhindered by the screws past each such bearing location. When a product carrier has arrived at the location illustra¬ ted in Fig. 3 to 5, corresponding to the switching station 11 according to Fig. 2, the transporting screw that advanced the product carrier is stopped, All transporting screws are stopped in a predetermined angular position, wherein the end 35 of the screw thread is located below the level of the lower surface 44 of the ridges 43 and 45, respectively, co¬ operating with the screw at the bottom side of the product c rier. In the position of the product carrier shown in Figs . 3 to 5, i.e., at the switching station 11, the location of the product carrier is fixed since each of the ridges 43, 45 are in abutment with the first thread of each of the four transporting screws which have connection with the switching station . It should be remembered that the ends 35 of the threads of all those transporting screws , when they are idle , are always located at a level below the lower surface 44 of the ridges 43 , 45 of the product carriers . This means that a _ product carrier ,which is advanced by one of the screws , while the remaining three screws are idle , unhindered by the thread ends 75 of the three idle screws , can be placed in the correct position centrally of the station 11 , where the product car¬ rier will become fixedly positioned by means of the ridges 43 , 45 abutting the first thread ridge of all four connected screws . It also means that thereafter a product carrier may be trans¬ ported from the switching station by driving any one of the transporting screws , while the remaining screws are idle , the direction of rotation of the driven screw being opposite to the direction of rotation of the s ame screw upon advancement by means of said screw of the product carrier in a direction towards the switching station . In a system comprising a plurality of switching stations and a plurality of transport lines it is thus easily possible , by driving different transporting screws in turn, to secure that each product carrier will arrive at its special destination . Another important advantage of the system disclosed is evident from the following . Since the transporting screws are always stopped in a predetermined angular position , a transporting screw , which has been started, will always complete an inte¬ gral number of revolutions before it is stopped again . Accor¬ ding to the invention this feature may be taken advantage of in a simple manner by utili zing means known per se for counting and recording the number of revolutions completed by each screw taking part in the transport of the product carrier in question , whereby an exact information is obtained of where a certain- roduc • carrier is situated in the transport system at any moment, and it may not least be utilized, by pre-pro- gramming the operation of the transporting screws relevant for the transport of a certain product carrier , to secure that the product carrier will reach its ultimate destination in the shortest possible time. In Fig. 1 a station 13 is illustrated, wherein a product car rier can be turned around a vertical axis for transferring same to a transport line 3a, 3b which is not parallel or per pendicular to the other transport lines referred to. The tur ning station comprises carrier beams 6a, 6b with carrier rol lers 7 and a motor driven transporting screw 15. The frame formed by the carrier beams and the members supporting said beams is mounted on a turning platform 37 so that it is rota tably around a vertical axis 38 and adjustable from the posi¬ tion shown in Fig. 1 by full lines to the position shown in Fig. 1 by dotted lines, in which the carrier beams 6a, 6b ar located aligned with the carrier beams 3a, 3b of the angular disposed transport line. The switching of the. assembly 13 ar the axis 38 between said positions may be performed simply b means of driving members not shown, e.g. one or more hydrauli cylinders or electric motors, in a manner known per se. The turning station 13 increases the possibilities of transporti product carriers along the shortest possible path to desired destinations within a given region. In Fig. 10 an assembly is shown for transferring a product carrier between a transport line inclined to the horizontal plane and a transport line in the horizontal plane. The asse ly comprises carrier beams 111 with carrier rollers 7, a tra porting screw 15 and a drive motor 17 with belt 19. The asse ly 73 comprising said components is rotatably mounted by mea of a horizontal shaft 75 on a column 71 supported by legs 70 through shifting of the assembly about the shaft 75 can easi be performed by means of hydraulic or electric means in a we known manner. It is evident that when the assembly is shifte from the position shown in Fig. 10 by dotted lines, in which it is aligned with a connected transport line, e.g., la, lb according to the Figure, to the position shown by full lines, the screw 15 of the assembly 73 will by engagement with the f OMPI ridges at the bottom of the product carrier in a manner des¬ cribed above, prevent uncontrolled sliding of the product carrier on the carrier rollers 7 of the assembly. The product carriers can be moved in height upwards as well as downwards by means of the assembly illustrated for the transfer of the product carrier to a transport line directed obliquely down¬ wards or upwards, respectively, (not shown). In Fig. 11 an arrangement is shown comprising an assembly 83 with carrier beams 84, a transporting screw 15 and transport rollers 7, said arrangement enabling the inclination of the transport carrier around a shaft 85 in parallel with the axis of the appertaining transporting screw 15 and by means of which the assembly 83 is pivotably supported by a column 81 of a supporting frame placed on a base. The supporting frame com- prises legs 80 which support the column 81 by means of a fulc¬ rum 87 having a vertical axis of rotation. The object of the arrangement according to Fig. 11 is primarily to turn the pro¬ duct carrier in a transport flow to a selected direction la¬ terally and to a selected angle of inclination, the latter upon transport along an inclined assembly line for instance. The Inclination of the carriers as shown in Figs . 10 and 11 may also facilitate the picking of products from the product carrier. The stacker 21 shown in Fig. 1 may be positioned adjacent the line in the transport flow or at a storage place. Such stackers which can also be controlled by a computer program, can be ar¬ ranged in such a manner that when a product carrier has been advanced and stopped in position for the stacker, lifting arms 23 are extended from their idle positions forwards to the pro- duct carrier, grip it by means of the arms 23 in the open aper¬ tures 47 and lift the product carrier upwards from the trans¬ port line to such an extent that a subsequent product carrier can pass well to a switching station, machining station, in¬ spection station or another storage place or pass below the raised product carrier and stop in position in front of the stacker,-which then receives an impulse to lower and thus stack the raised product carrier onto the one just arrived and then return to its idle position. The position in the stack of the product carriers now stacked one above the othe is defined exactly and the operation of the stacker can easi be recorded and controlled by means of a computer system bo at the build up of the stack, and also at the build down the of when product carriers are taken from the stack by means computer programmed transporting screws and transported to i dividual destinations or to a common place for storage. All product carriers, which are here loaded with details, which be placed on the product carriers in the coordinate or cont system selected for, e.g. a numerically controlled machine have thus their positions well defined not only in the horiz tal plane but also in height, whereby upon subsequent assemb or storage in spare parts storage each product carrier can b recalled to the position described in front of the stacker s as to be transported later by means of the screws by aid of the computer to a station, at which the products are picked from the product carrier, for instance by means of a robot. If the units included in the transport system of the inven¬ tion are dimensioned according to a convenient modular syste different systems may be built up of a minimum number of mut ally different parts. The decisive dimension for the transpo and storage system is the distance L between the centre line of the two ridges 43 at the bottom of the product carrier, see Fig. 5, said dimension being equal to the distance betwe the centre lines of the two remaining ridges 45. The modular length M of the frame parts is then determined i such a manner that one frame module comprises four pairs of carrier guide rollers 7, having a pitch (mutual distance) of M , arranged along their length, the width of the frame par 4 being selected so that the distance L between the longitu¬ dinal centre lines of the rollers 7 on the one and the other carrier beam is _3 M. It is evident that by means of the ar- 4 rangement of four pairs of carrier rollers per frame module a product carrier will always be supported by at least three pairs of carrier rollers, which secures the stability. Gene¬ rally, the centre distance between the roller pair at one end of the transport unit and the adjacent roller pair of an addi¬ tional transport unit connected to said transport unit should be identical with the equal centre distances between the uni¬ formly distributed roller pairs of each transport unit. The frame parts can also be made longer in order to be more easily combined to long transport lines. The length of the frame part is then always chosen to 2, 3, 4... n x M, i.e. an integral multiple of M. The number of thread turns of a transporting screw having a single thread start and a length equal to M is always an in- teger and the value of the number is selected so that the number of thread turns over a length L = __ M along the screw 4 is also an integer. Hereby a screw can always mesh with two of the four ridges of the product carrier and the product car¬ riers will always occupy well controlled positions, since the motor 17, as mentioned above, will start and stop the screw at one and the same point of the turn. For the transport of goods consisting of elongated details or the like, where said details extend longitudinally over two or more modules, product carriers 9 according to Fig. 4, 5 or 6 are not convenient. For such transport product carriers of a special design can be used, which may have any desirable length from 2 x M to n x M. In Figs. 12 to 14 it is shown that two ridges 91 cooperating with the transporting screws 15 at the bottom side of said product carriers have the same profile as the rims 43, 45 on the product carrier 9 but extend in a circ- 3 le with the diameter = L, i.e. _• M. The rims 91 are provided at both ends of the product carrier in the transport direction. At the transport across a switching station 11 and/or a sta¬ tion 13 for lateral turning for changing the direction of transport a smooth and continuous movement of the product carrier in the two transport directions across these two sta¬ tions is achieved by trigonometric computer control of the op ration of the two transporting screws, and hereby the product carrier will always be supported on each transport line si ul taneously by at least four carrier and guide rollers 7 or two carrier and guide rollers together with at least two ball rol lers 33. The product carrier 9b according to Fig. 15, 16 and 17 has th same task as the product carrier 9a according to Fig. 12 to 1 but is composed of two carrier units 101, which are provided with ridges 43, 45 according to Fig. 3 to 5 in a similar mann as the product carriers 9, said units then being coupled to a carrier platform 105 via a fulcrum 109 which is provided in t centre 107 of the carrier units and has a vertical axis. The distance between the two fulcrums can have the same selected modular length as the length of the product carrier 9a, but here an addition of a constant must be made to the length. Th condition is determined by the fact that in the use of produc carriers, which are provided with the same definite length, the transport lines at the switching stations 11 and the tur¬ ning stations 13 have always the same selected modular length in respect of their transporting screws up to the open module 12, which is- shown in Fig. 2 and 15, whereby the product car¬ rier 9b together with the carrier units 101 may pass via a switching station, the forwardmost carrier unit 101 being gripped by the screw in the new direction and leaving the for mer transport direction, said latter screw now being idle, th rearmost carrier unit instead being advanced by the screw out side the open module 12 due to the extension constant mention above. At continued transport across the switching station an the open module 12 the previously idle screw will grip the re carrier unit and upon continued transport of the product car¬ rier 9b from the station the movements described of the produ carriers and the screws are repeated. The direction of rota- tion of the transporting screws is determined by the transpor direction desired. The product carrier 159 shown from below in Fig. 18 is elon¬ gated and the bottom thereof is at both ends provided with a ridge 161 of halfcircular configuration having center axes 171, said ridges being identical and being interconnected by two straight ridges 165 the length of which being equal to the outer radius R of the ridges 161 and the distance between the center axes 171. The bottom flat surface of the ridges 161 is at the same level as the bottom flat surface of the strai.ght portions 165 and the bottom flat surface of two central areas 167 each adjacent one of said straight portions. This embodiment has advantages as follows. The elongated ridge configuration will enable a rectangular product carrier sup¬ ported by said ridge configuration to maintain its direction in the transport system. Product carriers in the form of boxes can be stacked independently of the oval ridge configu¬ ration. Product carriers equipped with a load platform and a load supporting beam swingably mounted at one of the center axes 171 of the ridges 161 can be used together with a similar product carrier having a corresponding load supporting beam for transporting elongated long products, since the transpor¬ ting screws will always maintain the correct distance between the center axes of the product carriers where the swingable beams are mounted, and this not only during transport along a straight line but also during transport via a switching station, if the beams are mounted at the center axes which give the shortest distance between the beams. In the product carriers described above the engagement members are formed by said ridges, the cross-sectional profile of which is shaped in correspondence to the profile of the thread grooves of the transporting screws . The contact between the ridge and the screw takes place along a line extending from the base of the ridge at the bottom of the product carrier to the bottom end surface of the ridge. By this line contact the material of which the ridges consists which may be plastic material, for instance, will be exposed to a high specific pressure in the narrow zone corresponding to the line conta and this may lead to a too rapid weardown of this portion o the ridge and a correspondingly reduced fit or play at the movement of the product carrier by means of the transportin screws and a deteriorated precision as to the determination of the position of the product carriers in the system. This can be avoided by providing the ridges with a profile as shown in Figs. 19 to 21. A characterizing feature of this improvement is that the inn side of the ridges at the location at which they cross the transporting screws are formed with a surface portion adapte to abut against the thread ridge of the transporting screws and having generally the same, geometrical form as the surfa of the thread ridge against which said surface portion abuts Preferably, said surface portion of the ridges of the produc carrier and the thread sides of the transporting screws are shaped so that a play, if any, in the engagement between the screw and the product carrier can be controlled and eliminat by changing the mutual height positions of the screw arid the procuct carrier. Figs. 19, 20 and 21 show a product carrier of this type as seen from below, from one side, and from the end, respective The product carrier is in the form of a box having rectangul shape and is provided at the bottom side with ridges or rims 203a and 205a which together form a square. The positions 221 of the ridges at which the ridges engage an underlying screw 12 is, according to the invention, forme with a surface portion at the inner side adapted to abut against the threόid ridge of the screw, the shape of said sur face portion coinciding with the helical surface of the side flank of the thread ridge, which flank as closely as possibl slides against said surface portion of the ridge and causes the advancement of the box in the system. Said surface por¬ tion 221 of the ridge, as illustrated in Fig. 21, is a circl IJTTREAZ O PI _ segment seen in projection in a plane perpendicular to the axis of the transporting screw, and its shape should be such that it makes contact along all of its surface with the flank of the thread ridge of the screw 12. Thereby, the specific pressure between the thread ridge and the surface 21 of the rim is reduced which, as mentioned above, will cause less wear and a reduced play in the system. The circle segment surface 221 can while maintaining its he¬ lical surface shape be more extended than corresponding to 0 the real engagement surface proper between the rim and the screw, whereby the shape of the engagement surface 21 and the flank of the thread ridge can be such that a reduction of the distance between the product carrier and the screw will cause elimination of the play, which may anyhow occur .*. 5 in the system, while an increase of said distance will cause the elimination of any seizures in the system. The proposed possibility of adjusting the mutual height position of the product carrier and the screw may also lead to somewhat lower requirements of precision in the manufacture of the product 0 carriers and the remaining system components. As mentioned above, the rims ridges 203a and 205a form a square but they may also form a rectangle or in certain applications , which are not described here, a circle. The external side 223 of the ridges may have a shape corres- 5 ponding to guide flanges provided on the carrier rollers of the system. The box-shaped product carrier is provided with handles 207a. Of course the product carrier need not always be of box shape. In some cases a simple board, for instance, without O side walls may be preferable. It should also be mentioned that the product carrier can be integrated with the product proper and be formed for instance by ridges of the kind mentioned above mounted or formed on the product. The surface portion of the inner side of the ridges according to the invention, abutting against the thread ridge and of special shape, may if desired, be covered by a more wear resistant material th the material of which the ridge proper is formed. In the re gion of said surface portion the ridge may as an alternativ consist of such a wear resistant material. As mentioned above, the transport system according to the i vention is particularly well adapted for control and monito ring by means of a computer system, which may be of a conve tionel type and therefor is not described more closely in t present connection. The principle is simple, since the com¬ puter system need only comprise means for controlling the drive motors included in the transport system for the trans porting screws 15 in such a manner that the motors will re- ceive impulses for rotation and integral number of revolu¬ tions, whereby the number of revolutions completed by each motor taking part in the transport of the product carrier can be recorded and each motor be stopped after completed the programmed number of revolutions. Then means are added for programmed control of the switching stations and the tu ning stations, as mentioned above, but also this feature be longs to elementary technique in the field of computer cont rol of mechanical systems. It should be remembered that each product carrier in the sy tem always has its position in space well defined since it always in engagement or has contact with threads of the tra porting screws of the components included in the system, an since in stacking and un-stacking, respectively, requires a control of the stacker which is easy to record and/or contr by a computer. Even when the product carrier is located on turnable units or inclineable units it is fixed in position by the engagement with a transporting screw of the system. weight of the product carrier and its contents, if any, wil prevent an inadvertent change of_ position in a vertical di- rection of the product carriers, which in the absence of st 5_R OM members of the transport units preventing movement upwards of the product carriers , are freely lif table at any time from the transporting units and replaceable , which is an advantage . As an . example of the type of motors , which may be used for the operation of the transporting screws comprised in the sys¬ tem of the invention , motors manufactured by Brown Boveri of the type AXEM may be mentioned, which allow a position control so that the driven screw will always complete an integral num¬ ber of revolutions and will not stop in an intermediate posi- tion . However, it is also possible to use normal , less costly asyn¬ chronous motors , given the fact that the speed of rotation of such a motor is almost unequivocally determined by the frequ¬ ency of the alternating current supplied to the motor. In such a case a static , 3-phase chopper may be used which generates a sinusoidal alternating current the frequency of which may vary between 0 (direct current) and 60 Hz (or higher) . The root mean square of the alternating current is maintained con¬ stant within the entire frequency range which results in a constant torque from stand-still up to the nominal speed of rotation , e . g . 50 Hz , of the motor. A digital control unit which can be controlled by a computer can be used for control¬ led acceleration and retardation (braking) , regulation of the speed of rotation and positioning . Two or more control units may be used to control more complicated situations . The only modification of a normal asynchronous motor that is required is the addition of an angle indicator having direction sen¬ sing means and zero position indication . In a practical em¬ bodiment said angle indicator may produce , for instance , 64 pulses per revolution of the asynchronous motor, said pul¬ ses being used for controlling the motor . The invention is not limited to the embodiments illustrated and described but may be realized in other manners within the scope of the appending claims . Thus , the product carrier,which in most cases will have the shape of a box may have any other shape and may also be inte grated with the product to be handled, since the product pro per may be provided with ridges , corresponding to the ridges 43 , 45 by means of which the product is supported by the car rier rollers and advanced by the transporting screws in the system. Further, it might be mentioned that the transporting screws , which preferably have one single thread start , may also be screws with two , three, etc. thread starts . In such case the drive of the screws may be such that the screw is always sto ped in a position corresponding to half, a third, etc, of a complete revolution . The engagement members in the form of ri dges at the bottom s of the product carrier has a profile corresponding to the groove profile of the transporting screw , but this feature need only refer to the central portion of the ridges , since the remaining portion of the ridge need only have such a pro file that it can pass by the thread ridges of the transporti screws at the switching stations at the same time as it un¬ rolls against the carrier rollers , as described above . The e gagement members need not either always be identical to the ridges , by means of which the product carriers are supported by the carrier rollers of the system, and which according to the embodiment examples form an unbroken rectangle , but the engagement members may if desired also be located for in¬ stance , immediately outside these ridges , provided that thei profile is such that the ri ges can pass freely through the screw grooves of the transverse transporting s crews . Since the mechanical work to be performed by the transportin screws is rather limited the screws can be of a light-weight construction and be made of a plastic material , or they may be manufactured by helical deformation or- deep-drawing of a thin-walled tube of steel or other metal .

Claims: CLAIMS . 1. A system for the transport of product carriers com¬ prising in a plurality of elongated transport units adapted to be interconnected to form a transport network, said trans¬ port units comprising a frame and an elongated transporting screw, driving means for rotating said transporting screw, the threads of which being adapted to cooperate with engage¬ ment members provided at the bottom side of the product car¬ rier in such a manner that the product carrier, when the screw is driven, is caused to move along the transport unit, said frame is provided with a plurality of rollers for supporting the product carriers during said transport, and that said transporting screws are adapted to be driven by the driving means in such a manner that they are always started and stop¬ ped in a predetermined angular position of the transporting screw, so as to allow the use of a computer control apparatus for permanent and exact control of the position of each pro¬ duct carrier in the transport system. 2. A system as claimed in claim 1, c h a r a c t e r i ¬ z e d in that the engagement members of the product carriers comprise two members mutually spjced longitudinally of the transporting screw with the same cross-sectional profile as the -thread groove of the transporting screws, each of said members meshing with the transporting screw during the trans¬ port. 3. A system as claimed in claim l or 2, c h a r a c t e ¬ r i z e d in that the frame of the transport units comprises two longitudinal carrier beams , each provided with a plurality of carrier rollers adapted to support the product carriers while unrolling against ridges or rims, provided at the bot- torn side of the product carriers, said transporting screw being located between and in parallel with said carrier beams. 4. A system as claimed in claim 3, c h a r a c t e r i ¬ z e d in that the ridges also serve as said engagement mem¬ bers . 5. A system as claimed in any of the preceding claims, c h a r a c t e r i z e d in one or more switching stations , adapted to interconnect two or more transport units and ar¬ ranged so that a product carrier at a switching station has its engagement members located immediately adjacent the thre ridge of the first thread turn of the transporting screw of 5 each of the transport units connected to the switching stati so that the product carrier from the position at the switchi station can be gripped by one and whichever of said transpor ting screws when rotated, said product carrier being then ad vanced along the transport unit corresponding to the rotated 10 transporting screw. 6. A system as claimed in claim 5, c h a r a c t e r i z e d in that said switching station comprises a frame, the upper portion of which comprising a plurality of support mem bers supporting said product carrier at the switching statio 15 and adapted to allow rolling transport of the product carrie in all transport directions represented by the transport uni connected to the switching station. 7. A system as claimed in claim 6, c h a r a c t e r i z e d in that the support members consist of balls rotatably 20 supported in spherical retainers. 8. A system as claimed in any of claims 5 through 7, c h a r a c t e r i z e d in that the switching station is square of rectangular with a connection facility for one transport unit at each side of the square or rectangle, res- 25 pectively. 9. A system as claimed in any of the preceding claims, c h a r a c t e r i z e d in one or more stations adapted to move a product carrier at a station horizontally between at least two transport directions and provided with roller 30 members for supporting the product carriers and a transporti screw with separate driving means. 10. A system as claimed in claim 9, c h a r a c t e r i z e d in that the station for moving the product carrier ho rizontally is rotatable about a vertical axis. 35 11. A system as claimed in any of the preceding claims, c h a r a c t e r i z e d in one or more stations adapted to move a product at a station in a vertical plane between at least two transport directions and provided with roller members for supporting the product carriers . 12. A system as claimed in claim 11, c h a r a c t e ¬ r i z e d in that the station for moving the product car¬ rier in a vertical plane is rotatable about a horizontal axis . 13. A system as claimed in claim 12, c h a r a c t e - r i z e d in that said station for moving the product car¬ rier in a vertical plane ia provided with a transporting screw with separate driving means and is rotatable about a horizon- tal axis, located in a common plane with the transport screw of the station. 14. A system as claimed in claim 12, c h a r a c t e ¬ r i z e d in that the station for moving the product carrier in a vertical plane is provided with a transporting screw with separate driving means and is rotatable about an axis, which is perpendicular to a vertical plane comprising the transport axis of the station, thus allowing the transfer of product carriers between transport units having different in¬ clination to the horizontal plane. 15. A system as claimed in any of the preceding claims, c h a r a c t e r i z e d in that the components included in the system, including the transport units, switching sta¬ tions and the stations for moving the product carriers in the vertical and horizontal planes, are composed according to a modular system, according to which the components have predetermined modular dimensions matched to each other, enab¬ ling the composition of transport systems of various dimension and various retwork configuration by means of a minimum num¬ ber of module types . 16. A system as claimed in claim 15, c h a r a c t e - r i z e d in that the transport units have a predetermined modular length (M) in the direction of the transporting screw and that the distance L between the centre lines of the rows of carrier rollers provided on each of the carrier beams of the transport units is equal to - M. 17. A system as claimed in claim 16, c h a r a c t e ¬ r i z e d in that the product carriers are provided at their bottom side with four ridges, serving as supporting members for the product carriers and as engagement members for the transporting screws, said ridges forming together a rectan- gular, substantially unbroken frame, the size of which is de 5 termined by the size of the product carriers, the distance between the centre lines of two opposite ridges of the frame being equal to L. 18. A system as claimed in claim 17, c h a r a c t e ¬ r i z e d in that each transport unit is provided with at 10 least four pairs of carrier rollers with an equal mutual cen re spacing, which at the same time is equal to the centre spacing between the roller pair at one end of a first trans¬ port unit and the adjacent roller pair of a second transport unit, connected to the first transport unit. 15 19. A system as claimed in claim 16, 17 or 18, c h a r a t e r i z e c in that both the modular length M and the dis tance L are an integral multiple of the extension in the lon tudinal direction of the transporting screw of a complete thread turn, half a thread turn, etc. of a transporting scre 20 having one thread start, two thread starts, etc. 20. A system as claimed in any of the preceding claims, c h a r a c t e r i z e d in that it comprises elongated product carriers, which are provided at each end portion with engagement members at the bottom of the product carrier 25 in the form of ridges forming frames, each being adapted to mesh at two positions with an underlying transporting screw, means being provided for such driving of the transporting screws of two transport units, connected to each other angul ly, that the elongated product carrier is transported from o 30 end to the other of the transport units. 21. ' A system as claimed in claim 20, c h a r a c t e r ¬ i z e d in that each of the ridge frames is circular and pr ferably fixed in relation to the product carrier. 22. A system as claimed in claim 20, c h a r a c t e - 35 r i z e d in that each of the ridge frames is square and mounted on a carrier unit, which in relation to the product carrier is turnable about a vertical axis through the centre of the square . 23. A system as claimed in any of the claims 1 to 20, c h a r a c t e r i z e d in that it comprises product car¬ riers provided at the bottom thereof with ridges for engage¬ ment with the transporting screws, said ridges comprising two half-circular ridges one at each end of the product carrier __._. and two ridges having a length equal to the radium of the half- circular ridges and inter-connecting the ends of one half-cir¬ cular ridge with the ends of the other. 24. A system as claimed in any of the preceding claims, c h a r a c t e r i z e d in that the inner side of the ridges of the product carriers , at the location at which they cross the transporting screws, are formed with a sur¬ face portion which is adapted to abut against the thread rid¬ ge of the transporting screws and has generally the same geo- metrical form as the surface of the thread ridge against which said surface portion abuts. 25. A system as claimed in claim 24, c h a r a c t e ¬ r i z e d in that, seen in projection in a plane perpendi¬ cular to the screw, said surface portion is substantially of the same size as a segment of the transporting screw, limited by a chord, forming a tangent to the bottom of the thread groove . 26. A system as claimed in claim 24 or 25, c h a r a c ¬ t e r i z e d in that said surface portions of the ridges and the thread flank of the transporting screws are shaped so that the play in the engagement between the screw and the product carrier can be adjusted by changing the mutual height position of the screw and the product carrier. 27. A system as claimed in any of the preceding claims, c h a r a c t e r i z e d in that the transporting screws of the transport units and other components are rotatably supported by bearing members in such a manner that no fixed part of the bearing members extends higher than the level of the bottom of the thread groove at the upper portion of the transporting screw cooperating with the engagement members of the product carrier. 28. A system as claimed in claim 27, c h a r a c t e ¬ r i z e d in that the transporting screws are rotatably sup- ported in mountings, which within the screws support a beari sleeve for roller bearings, having a shaft stud secured at both ends with the end portions of the screw or screw por¬ tions located on either side of the bearing location. 29. A system as claimed in any of the preceding claims, c h a r a c t e r i z e d in that the transporting screws are formed by helical, preferably rolling deformation or dee drawing of a thin-walled steel tube . 30. A system as claimed in any of the preceding claims, c h a r a c t e r i z e d by a computer apparatus for the control of the operation of the transporting screws of the system according to a predetermined program for each product carrier and for the recording of the number of revolutions completed by each of the transporting screws taking part in each transport for allowing identification at any moment of the position of the product carrier in the transport system. 31. A component, e.g. a transport unit, turning unit, et preferably in modular design, adapted to be included in a transport system as claimed in any of the preceding claims. 32. A product carrier, preferably of plastic material, adapted to fit into a transport system as claimed in any of the preceding claims . -£_REA OMP WiPO

Inventors: EDENAES B, GARDENBORG J
Applicants: EDENAES B, GARDENBORG J, KNIGHT KONSULT ING, KNIGHT KONSULTERANDE INGENJOERER AB
Application year: 1979
Main classification: B65G33
IPC codes: B61B13, B65G33, B65G43, B65G47