CONVEYOR SYSTEM WITH TRACK-GUIDED TROLLEYS AND DRIVE CHAIN

Abstract: A conveyor system with track-guided trolleys carrying the conveyed loads and where the trolleys are driven by a drive with driving members which are adapted to engage or to be released from a trolley is designed in such a manner that the drive chain (10) is placed in a track (8) above the trolley track (7) and that the driving members (6) are suspended from the chain freely movable perpendicularly to the direction of the chain and that the trolley (1) comprises a travelling part in the track (7) and a trolley plate (2) secured to the travelling part. The driving member (6) is a bar arranged in a chain link in the drive chain (10) so that it is freely movable in a plane perpendicular to the longitudinal direction of the chain and the trolley plate (2) is symmetrical on the longitudinal direction and provided with recesses (3) whereinto the driving member (6) can be introduced and engage the trolley (1). There is thus obtained a conveyor system where the engagement and disengagement mechanism between trolley and driving member is quite simple and where no movable coupling mechanisms are mounted on the trolley.

Description: CONVEYOR SYSTEM WITH TRACK-GUIDED TROLLEYS AND DRIVE CHAIN The invention relates to a conveyor system with track-guided trolleys carrying the conveyed loads and is moreover of the kind described in the intro¬ duction to claim 1. Such conveyor systems are used in innumerable places such as in production plants or service facilities where a large number of units are moved around in a plant or facility during the processing or working up of some kind of the units. * - In systems of this kind the chain with the driving members generally run constantly. The track-guided trolleys are carried along according to require¬ ments and carried by main tracks and/or branches dependent on conditions in the individual plant or factory. There are therefore various kinds of mechanisms permitting engagement and disengage¬ ment of the trolleys from the drive chain. The trolleys are normally provided with a locking or gripping mechanism which may engage a passing driving member which member is releasable so that the trolley is not carried further for example if the trolley is to wait for the correct position¬ ing of a points or if it meets an accumulation stop in front of a working station, a storing or packing station or a buffer store on the produc¬ tion or working line. These mechanisms are often of a complicated nature having many moving parts provided on every single trolley because the mecha- nis , the driving members and the trolleys must be adapted in such a manner that a driven trolley meeting a parked trolley on the track immediately by the impact with the parked trolley is disengaged from the driving member. The mechanism must moreover be designed in such a manner that an accumulation of parked trolleys that are to be put into service- again are always and automatically started from the front end in the direction of travel i.e. the front parked trolley is to start first even though a driving member will first meet the rear trolley in the line. . . It is the object of the invention to provide a conveyor system of the described kind where the engagement and disengagement mechanism between trolley and driving member is very simple thus obtaining a very reliable system. This is achieved by designing the system according to the invention as further disclosed in the char¬ acterising part of claim 1. There is thus obtained a conveyor system which find many, applications and which due to its structure is very simple to design with branches and points. The actual mechanism on the trolley has no moving parts whats¬ oever the driving member merely making a simple mechanical engagement with the trolley plate. If the system according to the invention is further designed as disclosed in claim 2 , there is obtained a very simple mechanical design of the driving member in that it simply consists of a bar that is exclusively pivotable in the direction perpendi¬ cular to the longitudinal direction of the chain and which by gravitation can be made to engage a trolley. By designing the trolley in the system according to the invention as disclosed in claim 3, it is possible to have the driving member run on the side of the trolley track which is most advanta¬ geous for the moment. It is thus possible to have driving members on one side of the track for a distance thereof and to have driving members on the other side of the track for another distance -thereof. It is also possible to have designs where a drive chain extends on both sides of a track - at least for a distance of the track - so that a trolley is delivered by one drive chain and taken over by another one. By designing the system according to the invention as disclosed in claim 4, a driving member will be lifted out sideways by the pusher part so that gravitation may force the driving member into the first available recess and carry along the trolley. If the trolley is moreover designed as further disclosed in claim 5, the rear part of a trolley can reach over and block the recess of the succeed¬ ing trolley so that a passing trolley will always engage the front trolley. At the same time the rear part of for example a parked trolley will act as a disengagement mechanism for the driving member on impacts or accumulation of trolleys. This simple disengagement mechanism has no moving parts whatsoever and thus require no maintenance at all. For practical purposes the system according to the invention is designed as further disclosed in claim 7. There is thus obtained a low-cost system because it is possible to use the same metal profiles for the trolley track as well as for the chain track. The brackets positioning the tracks in relation to each other may secure the chain track so that the driving members run on the desired side of the trolley track and by simply turning the brackets, the driving members are moved to the other side of the trolley, track. Where the system according to the invention is to be used for an installation with few branches, it may preferably be designed as disclosed in claim 8. This is possible because among other things it is of no importance on which side the driving members run and because it is simple to have a chain track in systems of this kind extend so as to form a loop and intersect its own course. Thus the usual accessories by the points are saved in that the continuous chain will drive the main track as well as carry the trolleys a distance onto the branch. Since it is the same chain that runs on the branch as well as on the main track there is automatically always synchronisation between the driving members. The usual accessories by points are generally synchronised with the main track in order to assure a reliable passage 1 of the points. Points in the system according to the invention are preferably designed as further disclosed in 5 claim 9. The simple design of trolleys and driving members means that on a points there will merely have to be arranged some fixed stopping plates. The point mechanism itself will thus. automatically guard against accidents in that, the position of 10 the points will automatically place the mounted stopping plates in the correct position. The conveyor system according to the invention is particularly - suitable for being designed such 15 that large volume loads are conveyed. It is possi¬ ble to couple for example two trolleys as further disclosed in claim 10 whereby the pull is transmit¬ ted directly to the following trolley. This will permit travelling in smaller curve diametres in 20. track curves. On the rear trolley it will of course be necessary to block the driving member recess so that the driving member can only engage the front trolley and bring same along. 25 The invention will be further described in the following with reference to the drawing wherein Fig. 1 is an inclined view of a section of a conveyor system according to the 0 invention and a trolley freely arranged in front of same. Fig. 2 is a sectional plane view along line II-II in Fig. 1, Fig. 3 is a schematic view of a conveyor system according to the invention having a single branch, Fig. 4 is a schematic view of the same system as in Fig. 3 but designed according to conventional techniques. Fig. 5 is a schematic view . of a convergent points according to the invention, and Fig. 6 is a schematic sectional plane view through a system• with coupled trolleys carrying a heavy load. On the drawing, see particularly Figs. 1 and 2, the reference numeral 1 refers to a trolley with wheels and bearings and an underslung trolley plate 2 ,designed symmetrical on its longitudunal axis. The function of the trolley plate is partly to form the basis of suspension of the load to be conveyed and partly to form that part of the trolley which a "driving member will engage. The trolleys travel in a trolley track 7 and the drive chain 10 which is only sketched extend in a chain track 8. The two tracks are built up by longitu¬ dinally extending hollow metal profiles having rectangular or quadratic cross-section and with a downwardly facing longitudinally extending slot 21. The slot 21 in the trolley track 7 makes room for the means securing the trolley plate 2 to the trolley 1 itself. The* slot 21 in the chain track 8 makes room for hinged joints whereto driving members 6 are secured so that they may reach beyond the actual track profile. The driving member 6 is hinged in such a manner that in relation to the chain 10 it can only pivot in a plane perperdicular to the chain corresponding to the plane II-II, cf. also Fig. 2, where the double arrow shows the possibilities of movement of the driving member. The actual trolley 1 with wheels and bearings and the drive chain 10 are moreover of a generally known nature and will therefore not b any further described in the present application. Likewise the drive mechanism for the chain and lubrication and cleaning means for chain and trolley are of a generally known kind and will be described no further. The trolley on the contrary is designed with a trolley plate 2 having a particular design * In the front end of the trolley plate in the direction of travel - as indicated by an arrow in Fig. 1 - there is on either side arranged a recess 3 which may receive a passing driving member 6. When a driving member engages a trolley plate 2, the drive chain will thus drive the trolley and any load secured thereto. In case the trolley is to be disengaged from the driving member, such disengagement may be effected by having a means force the driving member out of its engagement with the trolley plate. Such a means may consist of a metal plate with an inclined face pushing the advancing driving member away from the trolley plate which means may be . rigidly secured by the track or is pivotably secured and carried to its active position by an electromagnet, a pneumatic or hydraulic cylinder or a similar actuation means. The disengagement may also be effected when a driven trolley meets a parked trolley in that the rear part of the trolley plate is designed with fin-like parts forming a pusher part 4 with a guiding edge 11. When a driven trolley meets a parked trolley, the pusher part 4 on the parked trolley will release the driving member 6 and the driven trolley is thereby parked next to the one already parked. The pusher part 4 is offset a distance 5 corresponding to a little more than the. plate thickness of a trolley plate so that a following trolley can reach somewhat under a parked trolley. In order that parked trolleys can be disposed as closel as possible to each other the rear part of each trolley is provided with a recess 12 wherein the supporting means of the trolley plate can be introduced. When a line of parked trolleys is to be moved forwards one at a time for example because they are accumulated in front of a working station, the driving members coming from behind will always pick up the parked trolleys from the front end so that the front parked trolley is driven along first because the driving member will pass all the parked trolleys but the front trolley because the recess 3 of the trolleys is blocked except on the front trolley. Fig. 1 moreover shows how the chain track 8 is mounted in relation to the trolley track 7 in that a bracket 9 is used retaining the two tracks at the correct distance from each other and staggered in horizontal as well as vertical direction. Since the trolley plates are symmetrical on their longitudinal direction, the driving member 6 can be carried forward on the side of the trolley track which is most advantageous.. The bracket 9 is merely turned whereby the chain track is retained at the correct distance from the trolley track but on the opposite side. Fig. 3 schematically shows a conveyor system according to the invention wherein the arrows indicate the direction of travel of the .chain. The main track 7 with the chain 10 extends from the left at the top to the right and back again from the right at the bottom to the left. Reference numeral 13 indicates a branch where the centre part may be a hand-operated track which can be coupled to the main track by two points 15. By letting the chain 10 run in loops as shown in the drawing, the same chain can drive the main track as well as a section of the branch in that the chain can drive the trolleys a distance onto the branch as well as drive trolleys from the branch 13 onto the main track again. This is possible because the driving members may run on either side of the trolley track without problems. By the two points the looped chain part overlaps that part of the chain which is on the main track. There will thus be no accumulation of trolleys and chain parts on the main track and the branch will always be fully synchronised. Such a points is very simple and no further accessories are required which is necessary by the known points shown in Fig. 4. Fig. 4 shows the same track as in Fig. 3 but made by using generally known techniques. In order to move the trolleys at least a distance onto the branch 13 or from the branch 13 onto the main track again, there are arranged- by each points 15 so-called transfer apparatuses 14 consisting of a short, independent and endless chain with driving members and with its own driving engine M. This system, however, requires that the speed and position of the driving members of the transfer apparatuses 14 are synchronised with the driving members of the main track if the system is to work without problems. By designing the system according to the invention as shown and described in connection with Fig. 3, the need for using the costly transfer apparatuses is totally avoided and the chain parts are in synchronism without having to use any further accessories. Fig. 5 ' shows a points 15 comprising the point parts 16 and 17 which are movable as shown by the double arrow. The drive chain is as shown moved by the chain parts. Rigidly secured to the point parts 16 and 17 there may be provided stopping plates 18 having an inclined pusher or guide edge forcing the drive member out of its engagement with the trolley in case the trolley is not to enter the points for example because this has not been shifted for entrance. If the chain 10 extends as shown in Fig. 3, it is possible by means of the position of the points to ensure that two trolleys will never meet directly in the points and by a correct choice of the size of the loop, waiting time by the points may be minimised. Fig. 6 shows how a heavy load 19 is conveyed by the system according to the invention. The trolley 1' is coupled to the trolley 1 by means of a length of chain 20 made by quite the same chain as the drive chain 10. Thus the coupled trolley 1' is indirectly driven by the drive chain 10, namely through the pull of the drive chain 10 in the trolley 1. It thus becomes possible to convey heavy loads 19 in curves with a fairly small curve diametre because the pull from the trolley 1 is transmitted directly to the following trolley and not through the load 19. In Fig. 1 of the drawing the driving member 6 is shown as a quadratic bar. Practical tests have shown that the bar which may also have rectangular cross-section should have rounded corners so that it more easily engages and more easily disengages the recess 3 in the trolley plate 2. It has proved to be particularly advantageous with a driving member having circular or oval cross-section in that it is possible at the same time to give the front straight edge of the recess 3 in the trolley plate 2 a small negative angle of a few degrees so that the recess 3 becomes somewhat wider towards the bottom thereof. A driving member having circular cross-section is particularly preferable • due to the low manufacturing costs.

Claims: PATENT CLAIMS 1. Conveyor system with track-guided trolleys carrying the conveyed loads and where the trolleys are driven by a drive chain with driving members which are adapted to engage a trolley and drive same in the track, the drive members and the trolleys being so arranged that engagement and disengagement can be effected, c h a r a c t e r i s e d in that the drive chain (10) is arranged in a track (8) above the trolley track (7) and that the driving members (6) are suspended from the chain freely movable at right angles to the direction of the chain and that the trolley (1) comprises a travelling part in the track (7) and a trolley plate (2) secured to the travelling part, said plate being adapted to engage a driving member (6) . 2. Conveyor system according to claim 1, c h a r a c t e r i s e d in that the driving member (6) is a bar arranged in a chain link of the drive chain (10) in such a manner that it is freely movable in a plane perpendicular to the longitudinal direction of the chain. 3. Conveyor system according to claim 1 or 2, c h a r a c t e r i s e d in that the trolley plate (2) is symmetrical on the longitudinal direction corresponding to the longitudinal direc¬ tion of the chain and that on either side of the front part in the direction of travel there is provided a recess (3) whereinto the driving member (6) can be introduced and thus engage the trolley (1). 4. Conveyor system according to any one of claims 1-3, c h a r a c t e r i s e d in that on either side of the rear part of the trolley plate (2) there is designed a pusher part (4) comprising a guiding edge (11) which is adapted to push the driving member (6) in a direction away from the trolley track (7) . 5. Conveyor system according to claim 4, c h a r a c t e r i s e d in that the rear part (4) of the trolley plate (2) is offset (5). in vertical direction relative to the front part with .at least the thickness of the trolley plate. 6. Conveyor system according to any one of claims 1-5, c h a r a c t e r i s e d in that the chain track (8) and the trolley track (7) are mutually offset in vertical direction preferably a distance corresponding to the width of the trolley track. 7. Conveyor system according to any one of claims 1-6, c h a r a c t e r i s e d the chain track (8) and the trolley track (7) are made of longitudinally extending rectangular or quadratic hollow metal profiles having a downwardly facing longitudinally extending slot (21) and that the profiles are mutually secured by brackets (9) which simultaneously hold the tracks at the correct distance from each other. 8. Conveyor system according to any one of claims 1-7, c h a r a c t e r i s e d in that it is arranged is such a manner that by points (15) the conveyor chain (10) will drive the trolleys on the track (7) as well as on at least a distance of the branch (13), the chain being carried to form a loop from the track (7) to the branch (13) and back to the track (Fig. 3). 9. Conveyor system according o claim 8, c h a r a c t e r i s e d in -that the point mechanism in points (16, 17) is designed with fixed stopping plates (18) having guiding edges which are adapted to discharge trolleys dependent on the position of the points. 10. Conveyor system according to claim 1, c h a r a c t e r i s e d in that the trolleys (1) are adapted to be coupled for example two and two by means of a length of drive chain (20) so that the pull from the front trolley engaging a driving member is directly transmitted to the following trolley (I 1 ).

Inventors: JENSEN H DEJBJERG, JENSEN, H., DEJBJERG
Applicants: ALCON AS, AL CON AS
Application year: 1985
Main classification: B65G17
IPC codes: B61B10