A METHOD AND TRANSFER VEHICLE TO ELIMINATE THE ACCUMULATION OF ERRORS OCCURRING IN THE PLACING OF PACKAGES IN A CONSECUTIVE STORE

Abstract: A method and transfer vehicle for the elimination of the accumulation of positioning errors of packages in storage places in a computer-controlled consecutive store, in which the packages (16) are stored consecutively on a base on the rails (2) of the transfer vehicle (1) and in which in order to remove a package in the centre the packages in front or behind must first be removed, and in which the transfer vehicle (1) includes a lifting device (4, 11, 13), which lifts the package it is desired to move clear of the base onto the transfer vehicle for transportation. Known store transfer vehicles of this type cause a detrimental accumulation of errors in the positioning of packages. In accordance with the invention the package (16) is centred in the direction of the store line in relation to the transfer vehicle (1) at least once during the time it is stored on the store line. This takes place most advantageously in connection with each lift and by means of the lifting device.

Description: A Method and Transfer Vehicle to Eliminate the Accumulation of Errors occuring in the Placing of Packages in a Consecutive Store The object of this invention is a method of eliminating the accu- mulation of errors in the placing of packages in a computer-controlled consecutive store, in which method the packages in the store are stored consecutively on a base on top of the rails of the transfer vehicle and in which in order to remove a package in the centre the packages in front of it must first be moved out of the way, and in which the trans- fer vehicle includes a lifting device, which lifts the package to be moved onto the transfer vehicle ready for transportation. The invention is also concerned with the realization of the method in the transfer vehicle. Finnish Patent Application 84409 and Patent 47559 show some kinds of consecutive stores, in which the packages are stored consecutively on top of rails and in which the transfer vehicle that travels freely beneath the rails includes a lifting device to take a package onto the vehicle for transportation. The system'includes placing devices that control the placing of the packages onto the desired position on the store line. In the first-mentioned application this is " realized with the - aid of a computer and a pulse-sensor device connected to it. In this the accuracy of the placing is even of the order of 1 mm. despite this the inaccuracy of the placing becomes significant in certain cases. Princi¬ pally this applies to such stores in which there are at least two store lines and transfer lines connecting them, which makes the automatic cir¬ culation of packages possible. If certain packages are stored for long times on such store lines from which there are otherwise many collect¬ ions these long-term storage packages must be moved and circulated even hundreds of : times. The knownτtransfer:fvehieles. " in this. " kind of store cause the accumulation of an error in placing. In practice this leads to the situation in which the position of the package begins to gradu¬ ally slip away from the calculated position on the store line and fin¬ ally incorrect operation arises because of this when the transfer ve¬ hicle places itself at a significantly different position to that of the package to be lifted. The problem thus arises from the multipli¬ cation of a smaiUlerror many times in the same direction. Generally this small errors takes place when the transfer vehicle lifts the package off the rails when it is not placed accurately in the centre of the vehicle. In practice the error has been observed to arise when the transfer vehicle arrives at the place of the package to be lifted always from the same direction. By means of the invention it is attemped to eliminated the accu¬ mulation of the previous depicted error in the placing of a package. The characteristic features of the method in accordance with the in¬ vention are presented in the accompanying Patent Claim 1. A centering on the store line carried out once is not always sufficient, if the store line is so long that in through circulation the package may ex¬ ceed the placing tolerance area. The improvement in the system shown in Patent Claim 2 solves the problem then. In this the transfer ve¬ hicle carries out the centering of the package in connection with each lift. First of all this has the advantage that the centering measure required is quite small. Secondly the combination of centering with the operation of the lifting device is advantageous because the system does not then demand external control for centering. The characteristic features of the three different kinds of transfer vehicles for the realization of the method are shown in Claims 3, } and 5- In these the' correction movement is carried out in connection with each lift and the position of the package is corrected immediately if it>has moved a predetermined amount from its calculated position, that is if it is outside of the area of tolerance. The centering devices shown in Claims 5. 6, and 7 are especially advantageous for the reason that only the very small force of the sensor is directed onto the package, for the sensor being a freely turning switching device it can be turned out of the road of the sliding device. In the case of weak packages, for example wooden platform, this is important as they may not necessarily withstand shifting taking place from the edge of the platform. In what follows the invention is illustrated by reference to the accompanying illustrations, which show some of the forms of application of the invention. Figure 1 shows one kind of transfer vehicle in partial cross-section Figure 2 shows a second kind of transfer vehicle in side view Figure 3 shows a third kind of transfer vehicle in partial cross-section Figure 4 shows the centering device of the transfer vehicle in Figure 3 in detail Figure 5 shows the operation of the centering device of the transfer vehicle in Figure 3 Figure 6 shows the operation of the sensor Transfer vehicle 1 ' travels with its wheels 3 supported on rails 2 Figure 1. The upper part of the rails 2 forms the storage base of the packages 16. The transfer vehicle 1 is pulled along the store line by means of cable devices. In the transfer vehicle 1 the principal compo¬ nents are the upper frame 4, the axles 5 that are jointed to it by means of the support arms 6, the underframe 8 and the lifting device cable wheel machinery that is installed on it. The upper frame 4 itself forms the lifting device in such a way that the lifting mechanism pulls the axles 5 together, when the support arms 6 lift the upper frame 4 and its surface plate froms the lifting surface. . The lifting mechanism includes the sliding device 11 fitted to the underframe 8, and to which one cable wheel is attached to turn, and which can if required be pulled along the frame?' beams *9 by tightening the cable 10. The springs 12 retain the sliding device 11 in the resting position at one end of beam 9 and the pull of cable 10 moves it to the other end. The lever arms 13, which pull the axles 5 inwards when the sliding device 11 moves along beam 9. when they lift the upper frame 4 carried by sup¬ port arms set at an angle and this in turn lifts the desired package clear of the rails, are placed between the sliding device 11 and the axles 5» The centering devices are formed by the pins 14, which are also con¬ nected by means of the levers 15 to the sliding device 11. The holes at the front and rear plates of the upper frame 4 act as guides for the levers 15- The upper end of the pins 14 is at the height of the surface plate of t&'e upper frame 4 when this is in the lower position. On account of the transverse movement of the siding device 11 and the rise of the upper frame 4 the centering pins 14 rise above the lifting surface of the upper frame 4 and move towards one another. One of the pins takes hold of the wrongly positioned package and moves it more to the centre of the transfer vehicle. When a heavy package is raised the transfer ve¬ hicle 1 moves itself in the direction of the package as the transfer cable and the rest of the construction gives way. When the package is lifted clear of the rails the transfer vehicle returns to the correct position. Figure 2 shows another form of application of the transfer device. 5 In this centering is carried out by the sloping surfaces 17 that form the upper frame 4. In this the package 16 is shown slightly to the side of the calculated storage position. In this centering takes place when the sloping surface 17 takes hold of the lower corner of the -package 16. As a result of this the package 16 moves more to the centre or as 10 in the case of the previous transfer vehicle 1 the positioning devices give way slightly and the transfer vehicle 1 moves more exactly under the package and when the package rises clear of the base the vehicle positions ϋtsel ' ft-a ithe oorrect pαsition. The basic construction and operation of the transfer vehicle shown 15 in figure 3 are of the same kind as those of the iδransfieir vehicle in Figure 1. The transfer vehicle 30 includes four wheels 33 running on bearing on axles 32. The frame part 19 is carried on the axles by means of the jointed arms 2-9.. The principal sliding device 31 is made to move, by means 1 of a cable mechanism using the cable 34, when the axles 32 , 20. are made to move inwards by means of the lever arms 35- The jointed arms 29 then staighten and lift the frame part 19 upwards. The lifitng cover 18 is able to move limitedly on top of the frame part 19« The movement of the lifting cover 18 is determined by beam 20 and the cen¬ tering devices connected toSit. In Figure 3 the transfer vehicle 30 is 25.. shown in the lower position, when the centering devices 24 at its ends are not operating but are turned to the lower position by means of the counter levers 26 supporting the axles 32. The sliding device 23 is formed of a bar secured to the rod 22, and which is normally free to move along the slot 21 in the beam 20. 30 Ia Figure 4 the centering mechanism is shown in detail in such a case in which the lifting cover is raised and the wrongly positioned package 16 has pushed the sensor 24 downwards. In a normal case the counter lever 26 pushes the sensor 24 up from besides the edge of the package. The lever 25 connected to them turns the switch device 27 35 out of the road of the slider 23, which is then completely free to travel along the slot 21. The lifting cover 18 then remains in place through friction for the duration of the lift. In figure 4 the wrongly positioned package 16 does not allow the sensor 24 to rise in which case the switch device 27 remains in the road of the slider 23. The slider then presses against the switch device 27, which in turn presses againsti:the catch 28 in • beam 20 and the entire cover surface 18 with the package moves a small distance in the opposite direction to the deviation. It is essential that the components of the centering device are dimen¬ sioned in such a way that the push of the cover surface 18 takes place only after package 16 has been lifted clear. In Figure 5 the centering mechanism is shown from the side with the cover surface 18 in the lowered position. The cover surface 18 it¬ self is free to move on top of the frame part 19, which for this purpose is surface to reduce friction. In addition the position of the slider 23 is shown in various stages of the lift.'iA transverse beam is shown of the frame 19 of the transfer vehicle 30, on top of which the cover sur- face 18 is able to slide for a short distance both backwards and for¬ wards. The extreme positions of the cover surface are shown by broken lines. The sliding device 23 slides longitudinally along the slot 21 of the beam 20, and it is fastened to the arm device 22 secured to the axle 3.2. v in the starting position shown in Figure 5 the switch device 27 is still in the line of travel of sliding device 23, but when the lift¬ ing surface 18 rises the counter lever 26 of the sliding device 24 moves downwards, when bar 25 turns and the switch device 27 moves out of the road of slider 23. In Figure 5 position b of the sliding device 23 corresponds to a situation in which package 16 is already lifted off the base. After this the sliding device 23 moves along slot 21 on top of the switch device 27. If, however, package 16 is positioned on top of sensor 24, this cannot rise. Switch device 27 remains in place as shown in Figure 5 and the sliding device 23 pushes it .and in turn the catch 28 for a short distance. Movement takes place in a direction opposite to the d ia-arαn. in positioning. When package 16 is lowerd and lifting sur¬ face 18 has fallen to the lowered position slider 23 returns along slot 21 to the starting position. It then reaches the bottom of slot 21 before reaching-iits extreme position and pulls the lifting surface 18 back to the central position. In Figure 6 the sensor and centering devices' operation is shown from the front. In Figure 6 the situation in which a package pushed the sensor 24 to the level of the lifting surfaces 18 is shown by a contin¬ uous line. The switch device 27 connected to it is then in the line of travel of slider 23- In the situation shown by broken lines the sensor 24 is able to rise to the side of the package, when the switch device 27 remains beneath the line of travel of the sliding device 23. By a single lift package 16 moves to a more central position by ty¬ pically about 2 cm., so that the correction of a large error in posit¬ ioning requires a number of lifts. In any event the system prevents the accumulation of the error. This naturally presupposes accuracy and re- peatability in the positioning of the transfer vehicle itself, which can be achieved by the aforementioned known means.

Claims: Patent Claims 1. A method for the elimination of the accumulation of errors in the placing of packages in storage places in a computer-controlled consecutive store, in which in the store the packages (16) are stored consecutively on a base on top of the rails (2) of the transfer vehicle (1) and in which in order to remove a package in the middle the packages in front of or behind it must first of all be moved out of the way, and in which the transfer vehicle (1) includes a lifting device (4, 11, 13), which lifts the packages that it is desired to move clear of the base and onto the transfer vehicle (1) for transportation, characterized in that the package (16) is centred in the direction of the store line in relation to the transfer vehicle (l) at least once during the time that it is stored on the store line. 2. A method in accordance with Patent Claim 1, charact eriz ed in that the package (16) is centred by means of the lifting mechanism of the transfer vehicle (1) in connection, with each lift. 3. A transfer vehicle (1) travelling on the rails (2) of the store line intended to realize the method in accordance with Patent Claim 2, with inlcudes a cable-operated package lifting deice (4). on which the package on the base is lifted and which lifting device (4) of the transfer device (1) is arranged that in the lowered position it moves under the packages (lό) stored on the base, which lifting device includes a sliding device (11) arranged to be moved by the pull of a cable (10), which move¬ ment is transmitted to the lifting device (4) by means of lever arms (8) or similar, characterized in t a-t the transfer vehicle (l) includes cen- tering devices (14) placed at the front and back ends and that these are connected to the sliding device (119 by means of mechanisms e.g. levers (15), by means of which the centering devices (14) are arranged to move towards one another and centre the package to be lifted (lό). 4. A transfer vehicle (1) travelling on the rails of a store line intended to realize the method in accordance with Patent Claim 2, which includes a cable-operated lifting device (4), which lifts a package (16) placed on the base, and which transfer vehicle lifting device is arranged 5 that in its lowered position it can move under the packages stored on the rails, characterized in that the edges of the front and back ends of the lifting device include upwards opening sloping surfaces (17)' . which when they engage the edge of the package (16) are arranged to move the ! 0 package more to the centre of the transfer vehicle (l)-. 5. A transfer vehicle (.30) travelling on rails (2) intended to realize the method in accordance with Patent Claim 2, which includes a lifting surface on which the package (16) placed on the base is lifted 15 and which transfer vehicle (30) lifting surface (18) in its lowered posit¬ ion is arranged to move under the packages (16) stored on the base, and which inlcudes a lifting surface (18) arranged to move vertically by means of the pull of a cable (34) to lift a package (16) from the base and to carry it during transportation, characteriz ed in that 20 the lifting surface (IS) is free to move to a limited extent longitudin¬ ally on top of the frame part (19) and that the transfer vehicle (30) includes sliding devices (23) arranged to move by the pull of a cable (34) to move the lifting surface longitudinally if required and that both in front of and behind the transfer vehicle (30) there is a sensor (24) 25 connected to a switch (27), which is arranged to sense a package (ii6.ι);that is positioned outside of the tolerance area and to then turn the switch ((27) between the second slider (23) and the catch (28) connected to the lifting surface (18) in such a way that as a result of this the lifting surface (18) moves after lifting the package (16) clear longitud- 30 inally for a distance to correct the positioning error, and that the transfer vehicle ( 30) includes devices (21, 22, 23) to centre the lifting surface after the package (16) has been lowered. 35 6. A transfer vehicle ( 30) travelling on four wheels in accordance with Patent Claim 5, in which the front wheels and correspondingly the rear wheels are connected to one another by means of a common axle or other rod and the frame part (19) of which is carried by means of jointed 5 arms (29) from these axles, which are arranged to turn vertically by the pull of a cable (34) with the aid of the movement of a principal sliding device (31) arranged to move and to create a lifting movement, when the axles move towards one another, characteriz ed in that both sliding devices (23) ' are formed by 10. a transverse bar fixed to the ends of the arms (22) attached to the axles (23), which is placed to move a longitudinal slot (21) in the beam (20) attached to the lifting surface (l8), and a sensor (24) extending from the cover surface beyond the normal position of a package in such a way that a wrongly placed package (16) presses it down, when the switch (27) 15 turns to the line of the other slider (23) which pushes the catch (28) belonging to the beam (20) through the switch and through it to the lifting surface tiself (18). 7. A transfer vehicle (30) is accordance with Patent Claim 6, 0 characterized in that the front and rear arms (22) together with the sliding devices (23) and the slot (21) in the beam are arranged to pull the lifting surface (18) back to the central position after the package has been lowered when the axles withdraw to their extreme position in such a way that the out extreme positions of the sliding devices (23) 5 in the slot (21) correspond to the central position of the cover surface (18), when a possible deviation is corrected by the opposite side sliding device (23) when it withdraws to its extreme position. 0 5

Inventors: SUOMINEN SEPPO KALERVO, SUOMINEN, SEPPO, KALERVO
Applicants: SUOMINEN SEPPO KALERVO, SUOMINEN, SEPPO, KALERVO
Application year: 1987
Main classification: B65G1
IPC codes: B65G1