Patent Publication Number: US-3878793-A

Title: Floor conveyors

Description:
United States Patent 1191 Turner 5] Apr. 22, 1975 1 FLOOR CONVEYORS 3.103.895 9/1963 Bradt et al. 104 172 BT 3,174,439 3/1965 Edgar et al. 104/172 HT [75] Invent: Tum&#34;, Stevenage- England 3,262,397 7/1966 Bradt 104/172 BT [73] Assigneez Geo w King Limited, Stevenage&#39; 3,338,178 8/1967 Jones 104/172 BT England Primary Examiner-M. Henson Wood, Jr. [22] Flledi 1973 Assistant Examiner-Richard A. Bertsch [21] Appl. No.: 404,711  
  [57] ABSTRACT [30] Forelgn Apphcatlon Pnomy Data A tow-line conveyor system has a tow chain running in g a floor channel. A floor truck has a depending tow pin 2 engageable with the chain. The truck also has a defleeting pin positionable at any one of several loca- [52] US. Cl. 104/172 BT tions widthwise of the truck in dependence on a pre- [51] Int. Cl. B65g 17/42 selected transfer station for the truck. At the selected [58] Field of Search 104/130, 172 R, 172 B, transfer station the deflecting pin engages a floor- 104/ 172 BT, 172 C mounted deflecting plate, causing transverse movement of the tow pin and thus the truck, so that the tow [56] References Cited pin is moved from above the chain to above a second UNITED STATES PATENTS chain of a branch tow-line.  
 3,094,944 6/1963 Bradt et al. 104/ 172 HT 12 Claims, 6 Drawing Figures FLOOR CONVEYORS BACKGROUND OF THE INVENTION I. Field of the Invention This invention relates to a tow-line conveyor system and to a truck for use therein. I  
 2. Description of the Prior Art In a known tow-line conveyor system, a main towline is in the form of a chain running in a floor channel. The chain includes links having transverse driving slots engageable with a downwardly extending tow pin of a truck whereby the truck is towed by the chain.  
  The conveyor system comprises a number of transfer stations at each of which a branch tow-line branches from the main tow-line. Each branch tow-line can have its own towing chain. At each transfer station there is a first floor-mounted cam. The truck has a downwardly extending indexing pin which can be selectively located at a number of positions widthwise of the truck, each position corresponding to the position of a separate one of the first floor-mounted cams. Thus when the truck enters a station at which it is desired it should be transferred, the indexing pin, which has been positioned accordingly, contacts the first cam at that station. This causes a mounting rack holding the indexing pin to turn about a horizontal axis on the truck and thus to swing upwards two arms embracing the tow pin, whereby the tow pin is raised sufficiently to be disengaged from the driving slot of the chain of the main tow-line.  
  Just before being disengaged, the tow pin contacts a second floor-mounted cam which causes the pin to be moved transversely towards that side of the main towline from which the branch tow-line extends. When it has been so moved and also disengaged from the driving slot, the tow pin is moved further in the same transverse direction by a camming surface of the chain and transfer of the tow pin to the branch tow-line is thus completed.  
  This known system has various disadvantages. In particular, each truck has to be provided with the arrangement for converting pivoting force on the indexing pin to lifting force on the tow pin. This increases the cost of production of each truck. Moreover, owing to the provision of the second floor-mounted cam at each transfer station, each truck undergoes a transverse reciprocation at each station irrespective of whether the truck is to be transferred to the branch tow-line. This means that each truck is subjected to a large number of unnecessary transverse reciprocations, producing unnecessary wear and noise and risk of disturbance of a load in the truck.  
  In another known system with many features in common with that just described, the pivoting of the indexing pin produces through a complicated lever arrangement downward movement of a deflecting pin into a curved deflecting slot in a horizontal metal plate fixed in the floor. Thus, there is one such plate at each transfer station, engagement of the deflecting pin in the slot in the deflecting plate producing a transverse reaction force on the deflecting pin, and thus on the truck, urging the truck transversely of the first chain. This other system also has the disadvantage of increased cost of production of each truck, because of the arrangement whereby pivoting of the indexing pin causes lowering of the deflecting pin.  
 SUMMARY OF THE INVENTION According to the present invention, there is provided in a tow-line conveyor system, a combination comprising first and second towing chains, a load-carrying truck towed by a chain by way of a towing projection extending from the truck into towing engagement with the chain, and deflecting means which serve to deflect said truck laterally, thereby to transfer the projection extending from said truck from registration with said first chain to registration with said second chain at a selected transfer station of said system, said deflecting means comprising deflecting parts which are situated at respective transfer stations of said system and which, from the point of view of said truck as it passes said deflecting parts in turn, are distributed widthwise of the truck, and a deflecting part mounted on said truck and arranged to contact a selected one of said deflecting parts, by way of a deflecting surface oblique to said first chain as viewed in plan, whereby there is applied to said deflecting part by said selected one of said deflecting parts a component reaction force transverse to said first chain which force urges said deflecting part and thus said truck to move transversely to said first chain.  
 BRIEF DESCRIPTION OF THE DRAWINGS In order that the invention may be clearly understood and readily carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which:  
  FIG. 1 shows a diagrammatic, fragmentary, sectional side elevation of a truck and a floor chain of a floor conveyor system,  
  FIG. 2 shows a sectional front elevation of the truck and the chain,  
  FIG. 3 shows a sectional front elevation of a standard level-low level transfer station of the system,  
  FIG. 4 shows a sectional plan view of that transfer station,  
  FIG. 5 shows a sectional plan view of a standard levcl-standard level transfer station of the system, and  
  FIG. 6 shows a sectional front elevation of the latter station.  
  Referring to the drawings, the conveyor system includes a number of tow-lines in the form of endless floor chains running in channels in a floor 1. Various arrangements of the chains are possible, but for the purposes of this description it will be assumed that there is a main chain 2 and several subsidiary chains of which two are illustrated and referenced 3 and 4. Each chain is constructed and installed as disclosed in our co-pcnding Patent application No. 398,798. The chains tow load-carrying trucks by way of towing projections which depend from the trucks and towingly engage in open-sided recesses, such as the recess 5, in the chains. One of these trucks is shown and referenced 6 and serves to transport a motor car body, for example. It is provided with castor wheels 7 which roll on the floor l. The depending projection takes the form of a vertical towing pin 8. The pin 8 is mounted at the centre of the front of the truck by way of an automatic lifting device 9 which is known per se and which serves to lift the a pin 8 out of a receiving recess 5 should the device 9 strike an obstruction, such as the truck ahead. A biassing means in the form of a compression spring 10 encircling the pin 8 urges the pin downwards against the chain 2. The pin 8 has attached thereto near its lower end two horizontal lateral protrusions in the form of arms 11. Spaced apart along the length of the main chain 2 are transfer stations where the truck 6 may be transferred to a subsidiary chain, i.e., may be transferred from the main track to a branch track. Where the main chain is at a standard level and the subsidiary chain at a low level, which is lower than the standard level by at least the depth of the recess 5, each transfer station may be constructed in the simple manner shown in FIGS. 3 and 4. At the transfer station shown the chains 2 and 3 extend alongside and parallel to each other and travel in the direction of the arrow. There projects upwards from the floor a deflector part in the form of a deflecting member which consists of a vertical plate 12 inclined to the direction of the arrow, thus to provide a deflecting surface oblique to the main chain 2. The plate 12 is urged upwardly against limits by an underfloor spring so that it is automatically depressed and thus undamaged if run over by a fork-lift vehicle, for example. The steel channels 13 and 14 receiving and guiding the chains 2 and 3 are cut away at 15, as indicated by the cross-hatching in FIG. 4, over a length roughly equal to the length of the plate 12.  
  Widthwise of the truck 6, the truck is provided with two horizontal, parallel, vertically spaced strips 16 formed with pairs of vertically aligned bores 17 providing mounts. A deflecting part in the form ofa pin 18 attached to the truck 6 by means of a chain 19 is insertable into any selected one of these pairs of bores. When so inserted, the lower end of the pin 18 is just short of the floor l and serves to co-operate with the plate 12 at a selected transfer station. There are ten pairs of vertically aligned bores 17 distributed widthwise over the front of the truck 6 between the wheels 7, so that the pin 18 may be positioned at any one of ten positions across the truck, each position corresponding to a particular transfer station. The number of positions available is equal to at least the number of transfer stations in the system. Assuming that there are 10 transfer stations along the main track, the system will include ten deflecting parts, i.e. plates 12, one at each station. The plates 12 are arranged at different distances from the path of one of the wheels 7 of the truck 6, so that, from the point of view of the truck as it passes the deflecting parts 12 in turn, these parts 12 are distributed widthwise of the truck. To select the appropriate transfer station for the truck 6, the pin 18 is inserted into the appropriate pair of bores 17. As the truck 6 arrives at an inappropriate transfer station, its pin 18 misses the plate 12 at that station and so the truck 6 continues along the main track. As the truck 6 reaches the appropriate transfer station, its pin 18 contacts the plate 12 at that station and the towing force of the chain 2 causes the pin 18 and the plate 12 to co-operate with each other to displace the pin 8 from registration with the chain 2, through the cut-away 15, into registration with the chain 3. The reference numerals l8 and 8 in FIG. 4 indicate the position of the pins 18 and 8 immediately following the transfer operation. Unless the pin 18 happens to fall immediately into a recess 5 in the chain 3, it rides along the effectively continuous top running surface of the chain 3 until a recess 5 arrives, whereupon the truck 6 is towed away by the chain 3. FIG. 4 shows that the chain 3 may curve away from the chain 2 as at 3 following the transfer station.  
 Where the subsidiary chain cannot be at a sufficiently lower level than the main chain, then a transfer station as shown in FIGS. 5 and 6 is provided. At this station the two chains 2 and 4 extend alongside and parallel to each other and move in the direction of the arrow. There are mounted beneath the level of the floor, which is broken away in FIG. 5 for ease of.illustration, two hydraulic or pneumatic piston-and-cylinder devices 20 and 21. The piston of the device 20 provides power means and is attached to crosspieces 22 which carry a deflecting plate 12 and a ramp means in the form of a ramp plate 23. The piston of the device 21 is attached to a guided slide 24 on which is pivotally mounted an auxiliary pusher arm 25, there thereby being provided power-driven arm means. Referring to FIG. 5, the arm 25 can turn clockwise, against the action of a biassing spring (not shown), but not anticlockwise, relatively to the slide 24, from an operative position in which it extends across, and perpendicularly to, the chains 2, 4, and can be moved with the plate 24 from the full-line position 25 to the chain-line position 25&#39; shown in that Figure. FIG. 5 also shows switch means provided by pneumatic or hydraulic control valve 26 disposed ahead of the plate 12 on the intended path of the pin 18, as well as a station occupied limit switch 27 and a station cleared limit switch 28.  
  Assuming that the pin 18 has been positioned to select the transfer station shown in FIGS. 5 and 6, then, as the pin 18 passes over the valve 26, it operates the same to cause the valve 26 to actuate the device 20 to produce an upward stroke of the crosspieces 22. This brings the deflecting plate 12 and the ramp plate 23 from retracted positions into their projecting positions 12&#39; and 23&#39; in which they project upwardly through slots in the floor l. The plate 12 is advantageously spring-mounted on the crosspieces 22 so as to be depressed if run over by a vehicle. Following a short additional travel by the truck 6, one of the arms 11 rides up the ramp plate 23 and thus lifts the pin 8 out of engagement with the chain 2. At the same time, the pin 8 pivots the arm 25 clockwise in FIG. 5 until the arm 25 springs back to behind the pin 8 under the action of the biassing spring. The truck is now in a condition with the pin 8 disengaged from the chain 2 and with the pin 18 adjacent to the plate 12. In this condition the pin 8 operates the station occupied&#34; limit switch 27 to actuate the device 21 to cause the arm 25 to move from the full-line position shown in FIG. 5 to the chain-line position 25&#39; and thus pull the pin 8 forwards while the pin 18 and the plate 12 co-operate to deflect the truck 6 laterally, so that the pin 8 finally reaches the position 8&#39;. In this position 8 the arm 11 has been released by the ramp plate 23 so that the pin 8 has dropped into a recess 5 of the chain 4 or onto the effectively continuous top surface of the chain 4 to await the arrival of a recess 5. The chain 4 then tows the truck forwards. When this happens, the pin 8 operates the station cleared&#34; limit switch 28 to return the devices 20 and 21 and thus the parts 12, 23 and 25, to their original positions.  
  The arrangements described with reference to the drawings have several advantages. There is practically no chance of the tow pin 8 becoming jammed between the recesses 5 of the two chains or between a recess 5 and a channel during transfer, because the tow pin 15 is always transferred to a position immediately above the level of the top surface of the subsidiary chain 3 or 4. Moreover, the relative speeds of the chains are not critical, nor are the pitches of the trucks 6. The transfer region is not limited to both of the chains being parallel to each other. Transfer can take place at other angles and at bends of various radii. Furthermore, the metal channels in the floor do not need to be of a complicated cross-section at the transfer stations, and so can be of a conventional cross-sectional shape and size.  
  The simple transfer station of FIGS. 3 and 4 has the particular advantage that transfer is achieved without any external power supply other than via the tow chains 2 and 3. Also, the transfer station does not require any additional excavation other than a small cavity for the spring-loaded deflecting plate.  
 I claim:  
  1. In a tow-line conveyor system, a combination comprising first and second towing chains, a load-carrying truck towed by a chain by way of a towing projection extending from the truck into towing engagement with the chain, and deflecting means which serve to deflect said truck laterally, thereby to transfer the projection extending from said truck from registration with said first chain to registration with said second chain at a selected transfer station of said system, said deflecting means comprising deflecting parts which are situated at respective transfer stations of said system and which, from the point of view of said truck as it passes said deflecting parts in turn, are distributed widthwise of the truck, mounts on said truck distributed widthwise of said truck, a deflecting part mounted at a selected one of said mounts and movable, independently of said projection, from said one to another of said mounts, said deflecting part being arranged to contact a selected one of said deflecting parts by way of a deflecting surface oblique to said first chain as viewed in plan, whereby there is applied to said deflecting part by said selected one of said deflecting parts a component reaction force transverse to said first chain which force urges said defleeting part and thus said truck to move transversely to said first chain.  
  2. A combination according to claim 1, in which the chains are floor chains and the projection depends from the truck.  
  3. A combination according to claim 1, in which said deflecting parts each comprise a deflecting member extending obliquely to said first chain as viewed in plan.  
  4. A combination according to claim 1, and further comprising biassing means serving to bias said projection into contact with a chain with which it is in registry, said first and second chains extending alongside each other at said selected transfer station, each chain having an effectively continuous running surface for the projection, except for a plurality of recesses for receiving the projection, the arrangement being such that, with the projection in a recess of the first chain at said selected transfer station, at that transfer station the effectively continuous running surface of the second chain is situated on that side of a horizontal plane, containing the extremity of the projection, opposite to the side&#39;of the plane at which the projection extends, and the recess is open towards the second chain to permit the projection to move from the recess directly into contact with the second chain when the truck is deflected laterally at the station.  
  5. A combination according to claim 1, in which at said selected transfer station said first and second chains extend alongside each other, at said selected transfer station ramp means serves to withdraw from towing engagement with the first chain the projection of said truck entering that station.  
  6. A combination according to claim 5, in which power means is operable to move the ramp means to and from a position in which it withdraws said projection from towing engagement with the first chain, and switch means is operable by said truck approaching said selected transfer station to initiate operation of the power means to move the ramp means to said position.  
 7. A combination according to claim 1, and at said selected transfer station power-driven arm means serves to move in the direction of travel of the first chain said projection withdrawn by said ramp means, whereby said deflecting part of the truck is caused to contact the selected one of said deflecting parts to transfer the projection into registry with the second chain.  
  8. A combination according to claim 7, in which the arm means comprises a pivotally mounted arm biassed towards an operative position in which it extends across said first and second chains, the arm being pivotable in the direction of travel of the first chain from said operative position under action of said projection in towing engagement with the first chain, but retained against pivoting in the opposite direction from said operative position.  
  9. A combination according to claim 1, in which the deflecting part mounted on said truck is in the form of a pin, and said mounts comprise a plurality of pairs of vertically aligned holes for receiving the pin.  
  10. A combination according to claim 1, wherein the chains are floor chains, the projection depends from the truck, said deflecting parts are movable between projecting positions in which they project upwards from the floor and retracted positions, and there are biassing means resiliently biassing said deflecting parts into their projecting positions.  
  11. A combination according to claim 1, wherein said truck comprises a truck body mounting its towing projection, said mounts being fixed to said body so as not to be movable relative to said body.  
  12. A combination according to claim 11, in which the towing projection includes a lateral protrusion for co-operation with ramp means serving to withdraw the projection from engagement with said first chain.