US2780339A - Means for delivering metal or other sheets from a conveyor - Google Patents

Description

W. BELL Feb. 5, 19 57 MEANS FOR DELIVERING METAL OR OTHER SHEETS FROM A CONVEYOR 2 Sheets-Sheet 1 Filed July 10, 1953 w. BELL 2,780,339 MEANS FOR DELIVERING METAL OR OTHER SHEETS FROM A CONVEYOR Feb. 5, 1957 2 Sheets-Sheet 2 Filed July 10, 1953 MEANS FOR DELIVERING METAL OR OTHER SHEETS FROM A CONVEYOR William Bell, New Malden, England Application July 10, 1953, Serial No. 367,295 Claims priority, application Great Britain August 5 1952 4 Claims. (Cl. 198-33) The present invention relates to means for delivering metal or other sheets from a conveyor on which the sheets are supported edge on.

In, for example, the stove enamelling of printed sheets of tin plate or the like the sheets are carried through an oven on a continuously moving conveyor travelling at slow speed and comprising a number of closely spaced trays projecting upwardly from and carried by link elements of parallel conveyor chains which pass over and extend horizontally between sprockets at the inlet and delivery ends of the oven. These trays, when travelling through the oven are disposed at an obtuse angle to the horizontal part of the conveyor chains so as to have a slight backward slope, the printed sheets being inserted between the trays so that the non-printed side rests against the front surface of the respective backwardly sloping tray, the trays being spaced apart at their free upper edges by rearward projections therefrom.

in removing the sheets from the trays it is important to avoid contact of the printed side against the trays or any part liable to scratch the printed surface.

The object of the present invention is to provide improved delivery means which will operate automatically to remove sheets from a conveyor Whilst maintaining the same in the edge-on disposition the sheets so removed being, if desired, subsequently transferred to a horizontal position so that the delivery mechanism when combined,

for example, with stove enamelling apparatus as described above will operate to remove the sheets without damaging the printed sides thereof, the sheets also being delivered printed side uppermost.

The present invention provides therefore means for delivering metal or other sheets from a conveyor on which the sheets are supported edge on wherein the delivery means is arranged and operated in timed relation to the conveyor so that a sheet at the discharge end of the conveyor is engaged by the delivery means and moved from the conveyor by a continued forward movement the sheets being maintained edge on and with a rearwardly sloping disposition during the delivery movement.

The delivery means according to the present invention comprises preferably means for engaging the lower edge of a sheet and means for engaging the rear surface of the sheet, both said means being movable in a forward direction to move the sheet from the conveyor and during such movement to maintain the same edge on and with a rearwardly sloping disposition.

More specifically according to the present invention the delivery means comprises endless chains or the like provided with dogs for engaging beneath the lower edge of a sheet and further endless chains or the like provided with support members for engaging the rear surface of the sheets the movements of the endless chains being synchronised with each other and with the conveyor in such manner that initial movement of the sheet from the conveyor is effected by the combined movement of the'dogs and conveyor and finally by the combined movement of the dogs and the support members the sheets being maintained throughout such movements edge on and with a rearwardly sloping disposition.

Preferably the endless chains or the like conveying the dogs are arranged so that during initial movement of the sheets each sheet is elevated to bring the rear surface of the same into the path of movement of the support members for final delivery from the conveyor.

The delivery means of the present invention may be combined with receiving means onto which the sheets are discharged, the sheets as they are delivered by the delivery means being turned from the edge on disposition to a substantially horizontal position. The receiving means may consist, for example, of a conveyor belt the sheets discharged onto the conveyor belt being carried thereby to a discharge position for stacking.

The delivery means of the present invention is particularly suitable for the removal of printed sheets from an oven conveyor of the kind disclosed above and Wherein it is necessary during the removal of the sheets from the conveyor to maintain a printed or otherwise treated surface free from damage, it being possible to arrange the delivery means in such manner at the discharge end of the conveyor that as each sheet arrives adjacent the delivery end the same is engaged and moved forwardly by the delivery means in a direction corresponding to the direction of movement of the conveyor, the sheets being maintained edge on and with a rearwardly sloping disposition during such removal.

In order that the invention may clearly be understood and carried into effect an example of the same will now be described by aid of the accompanying drawings in which:

Fig. 1 is a side view showing diagrammatically the delivery means associated with and utilised for the delivery of printed metal sheets from the conveyor of a drying oven, the sheets being discharged from the delivery means by a discharge conveyor to a stack pile.

Fig. 2 is a side view to an enlarged scale, of the discharge conveyor for delivering sheets from the delivery means to the stack pile.

Figs. 3 and 4 show respectively in plan view the upper and lower conveyor of the delivery means, Fig. 4 being taken on the line 44 of Fig. 1.

Fig. 5 is a view in plan of a conveyor of Fig. 2.

Fig. 6 is a view seen from the delivery end of the discharge conveyor showing the sheet stifiening means, and Fig. 7 is a side view showing a portion of the discharge end of the discharge conveyor and the detector means for gauging the height of the stack pile.

In the drawings, the runs 1 of the oven conveyor, such, for example, the drying oven of a stove enamelling apparatus, at the delivery end of the oven conveyor, pass around pairs of sprockets 2 and 3, the upper pair of sprockets 3 being carried by a shaft 4 mounted at either end in bearings 5 supported by the horizontal member 6 of a fabricated framework forming part of the oven structure. The runs of the oven conveyor carry a plurality of spaced trays or frames 7 which support the enamelled sheets 8 printed side facing the direction of movement, in the oven conveyor, the printed sheets being supported edge on and with a rearwardly sloping disposition.

The delivery means shown in the drawings comprises a lower conveyor situated at the discharge end of the oven conveyor having means for engaging each printed sheet by its lower edge and an upper conveyor situated above the lower conveyor and having means for engaging a printed sheet by its rear or unprinted surface, the upper and lower conveyors being driven in synchronism with, but in the portion of the discharge .3 opposite direction to each other and in synchronism with the oven conveyor.

The lower conveyor comprises a pair of endless chains 9-each of whichis :supportedon-four sprockets arranged intwo pairs, a rear pair consisting of upper and lower sprockets 10 and 11 respectively and a forward pair 12 and-13 respectively.

The lower sprockets 11 of each pair of rear sprockets are mounted in close proximity to but angularly offset from and in a plane above the end sprockets 3 of the oven conveyor these sprockets 11 each being carried on a stub axle 14 supported on the horizontal frame members 16 which form arpart of the framestructure at the delivery end of the oven conveyor.

At each side of the frame structure, a frame member 18 extends upwardly from the frame member 16 and supports-a stub axle 17 onwhich is carried the upper sprocket .10 of each pair of rear sprockets. The rear upper sprockets '10 arepositioned so as to be angularly offset from andin a plane above the lower sprockets 11 so that the runs of the endless chains 9 between these two sprockets extend'upwardly and outwardly at an angle to the discharge end of the oven conveyor. Also the upper sprocket 12 of each forward pair of sprockets is disposed in ahigher plane than the plane of support of the upper sprockets 10 of the rear pair of sprockets so that the upper run of the endless chains 9 between such sprockets extends upwardly at an angle to the horizontal, the said upper sprockets being mounted on a common shaft 19 supported at either end in the diagonal frame members 20, whilst thelower sprockets are mounted on a common shaft 21 supported at either end-in bearings 21 carried by the frame member 16.

Each endlesschain 9 is provided along its length with a-seriesof equallyspaced dogs 22 which project outwardly I from the chain surfaces for engagement with the lower edge of :a printed sheet'S at the discharge end of the oven conveyor.

The upper conveyor consists ofa pair of endless chains 23 supported'at either end on'pairs of sprockets 24, 25. The sprockets 24 are mounted on each side of the centre of a shaft..26 the sprockets 25 being similarly mounted on a further shaft 27. The shafts 26 and 27 .are supported at each end on one of a pair of sideframe members 28, secured to the upper'e-nds of the vertical andidiagonal frame membersldand-ZO, the forward end of the side frame members 28 being securedtothe-upper ends of a further:pair offrame members 29 also projecting vertically upwards from the horizontal framemernbers 16.

The endless chains 23 are provided with sheet engaging means in the form. of a plurality of equally spacedrods 30 which project outwardly from the surface of the endless chains.

The endless chains of the upper and-lower conveyors are driven in opposite directions by a constant speed electric motor 31 the drive shaft of'which is connected through a fluid clutch 32'to the input shaftof a reduction gear box 33. The output shaft of the gear box 33 is provided with a sprocket 34 connected by a chain-drive 35 to a driving sprocket 36 keyed to shaft 21 carrying the sprockets 13 of the lower conveyor endless chains 9.

The endless chains 23 of the upper conveyor are also driven by the constant speed electric motor 31, but in the opposite direction to the endless chains 9 of the lower conveyor. For this purpose the shaft-21 is provided with a driving sprocket 37 which is coupled by a chain drive 38 to a driving sprocket 39 mounted on a stub axle 40 supported by one of the side frame members 28. The shaft 27 is driven from the sprocket 39 through the meshing gears 41 and 42, the gear 41 being spigotted to the sprocket 39-whilst the gear 42 is keyed to the shaft 27.

In the absence of any synchronised connection between the oven conveyor 1 and the endless chains'9 and 23 of the lower and upper conveyors respectively, the motor31 is arranged to drive the chains 9 and 23 at a speed in excess of that of the oven conveyor 1. Cyclic synchronisation between the oven conveyor 1 on the one hand and the lower and upper conveyors 9 and 23 on the other hand, is achieved by coupling the shaft 21 to the shaft 4 of the oven conveyor through a chain drive 43, one end of which passes around a sprocket 44 running on a .stub axle 45 supported by oneof the horizontal frame members 16. The shaft 45 has also keyed thereto an enlarged sprocket 46 which is connectedby a'further chain drive 47 to a sprocket 48 secured to the shaft 21. This coupling, whilst enabling cyclic synchronisation to be achieved, also permits the motor 31-to run at a constant speed in excessof that required, this excess being accommodated by slip in the fluid clutch 32.

While the delivery mechanism described above as each printed sheet 8 arrives at the discharge end of the oven conveyor its'lower edge is engaged by the dogs 22 and due to the angulardisposition of the portion of the .run of the endless chains 9 the engaged sheet is moved upwardly whilst continuing a-forward movement in'the same direction as the movement of the oven conveyor, the :sheet during such movement being continued to be supported by the tray '7 of the oven conveyor.

The uppersprockets of the rear sprocket pair are so positioned relative to the end of the oven conveyor .that as the sheet supporting-tray commences to swing forwardly as shown and as a result of the upper runof-the oven conveyor passing around the oven conveyor end supports the rear surface of the sheet is engagedby the rods 30 carried'by the upperpair .ofcndless chains 23 :the movement of these upper endless chains being synchronised sothat .each sheet so engagedis maintained in the same rearwardly sloping'disposition whilst continuing its movement in the direction forafinalx-delivery.

The supporting means carried by the upper pair of endless chains may consist, for example, of a series of equally spaced rods which project outwardly from the surface of each of said endless chains, eachsaid endlesschain'being supported at either end on sprockets.

As stated previously the upper'pair of endless 'chains are driven in the opposite direction to the endless chains of the lower pair with the result that'the lower:run of the upper endless ,pair of chains travels in the same direction as the-upper run of the lower pair of endless chains. The length of the rods carried by the upper endless chains is-such that when they project downwardly from the lower run of the said upper :pair of endless chains they engageithe rear end of a sheet adjacent'the upper edge of the same.

To maintain thetension of the upper pair of endless chains -.and prevent sagging of the lower run of the same which is increased by'the weight of the suspended rods, the chains-are run-in 'tracks (not shown) the shafts 26 being adjustable in the slots 2611.

With the-.above described-arrangementeachsheet as it reaches the delivery end of the oven conveyor isengaged at its lower edge by the dogs of the lower pair of endless chains and whilst still supported'by the tray of the oven conveyor is simultaneously lifted andadvanced in the direction of movement of the oven conveyor as a result of the angular setting of the run of the lowerpair of endlesschains betweenthe rear pair of sprockets the rearwardly sloping disposition of the sheet being maintained during such movement. The lifting movement of the sheet brings the upper edge ofthe same into the pathof movement of the .outer ends 'of the support members formed by the rods of the upper pair of endless chains,.and.as. the tray of the ovenconveyor commences toswing forwardly out of the sheetsupporting position the rear surface of the sheetsis engagedby a pairof said rods withtheresult ,thattheforwardzmovement of the sheet is continued'and .the rearwardlysloping disposition maintained.

As each sheet 8 reaches 'the'limit of travel of the area-3 39 lower pair of endless chains 9 at which point the upper runs of said chains pass around the upper sprockets 12 of the forward pair the lower edge of the sheet when (118- engaged from the supporting dogs is transferred to the upper run of a discharge conveyor, the sheet being continued to be supported at its rear by the rod of the upper endless chains. The run of the discharge conveyor slopes downwardly at an angle from the discharge end of the lower pair of endless chains and is driven in the same direction of movement. Thus as the lower edge of the sheet is advanced, due to the downward slope of the conveyor belt the rearward angle of slope of the sheet increases as the upper edge of the same is lowered until finally the said upper edge moves out of engagement with the rods of the upper endless chains and the sheet falls onto the belt conveyor by means of which it can be delivered to, for example, a sheet stack.

As shown in the drawings the discharge conveyor consists of a plurality of transversely spaced endless belts 49 the runs of which are arranged to permit adjustment of the conveyor length so that the position of the discharge end of the same may be varied relatively to a fixed sheet stacking position to permit the said discharge end to be moved towards or away from the fixed sheet stacking position whereby sheets of a smaller or larger size can be delivered to such sheet stacking position.

For the above purpose the belts are supported between two pairs of side frame members 50 and 51 respectively, the side frame members 50 being fixed and secured to the lower ends so as to be supported by the aforementioned v'ertical frame members 29.

The conveyor side frame members 51 are movable relatively to the fixed frame members 50, so as to be adjustable longitudinally of the conveyor, the lower edge of each said frame member 51 being provided with rack teeth 52 engageable by a rack pinion 53. The rack pinion 53 is secured to a shaft 54 carried by a bracket 55 mounted on the fixed frame member 50, the shaft 54 being provided at its outer end with a hand wheel 56 rotation of which effects any desired adjustment of the conveyor length.

The discharge conveyor is provided with five endless bands 49 one of which is disposed substantially on the centre line of the machine the remainder being disposed two on either side thereof as shown in Fig. 5. At the discharge end of the discharge conveyor the central band passes around a pulley wheel 58 each remaining band passing around a pulley wheel 57 of smaller diameter, the pulleys 57 and 58 being mounted so as to revolve freely on a common shaft 59 supported at either end in i the movable side frame members 51.

The upper ends of each conveyor belt 49 towards the rear of the conveyor pass around a guide roller 60 supported at either end in brackets 62 carried by the movable side frame members 51. The upper runs also pass around a further guide roller 63 which is in turn supported at either end in the brackets 55, the upper runs then continuing upwardly at an angle and around guide pulleys 66 and a guide roller 65, the guide roller being end supported at either end in brackets 68 projecting outwardly, from the vertical frame members 29, the guide pulleys 66 being carried by the shaft 19 of the lower conveyor of the delivery means.

The lower runs of each endless belt 49 pass around a jockey pulley 69 carried on one end of a weighted arm 70 which is pivotally mounted about its other end on a shaft 64 supported by the bracket 55, and around further guide pulleys 71 each of which is rotatably mounted on the aforementioned shaft 64. The belts 49 of the discharge conveyor are driven through a chain drive 72 by an electric motor (not shown), the chain 72 passing around a driving sprocket 73 secured to one end of the roller 63.

With the above described construction it will be appreciated that sheets having a printed or otherwise treated surface can be delivered to the belt conveyor with the printed or treated side uppermost so that thesame are maintained throughout their travel through the oven and delivery means out of contact with any parts of the mechanism which may cause scratching or other damage to the said surface. I

The printed sheets 8 delivered by the discharge conveyor are discharged to a loading platform 74 situated in the stacking position the platform being mounted so that the same is vertically displaceable, the platform being automatically lowered as the height of the sheet pile increases.

For example, the loading platform may be suspended in a supportingframe 75 by chains carried by toothed sprockets the sprockets being driven through suitable gear ing by an electric motor the circuit of which is opened or closed by switch means the operation of which is controlled by detector means for gauging the height of the pile. The detector means is operable to close the motor control switch when the sheet pile reaches a predetermined level, operation of the electric motor serving to move the platform 74 downwardly to a lower level to permit further delivery of sheets to the stack pile.

As shown in Fig. 5 the detector means consists of a plunger 76 which is pivotally mounted at 77 to one end of an arm 78 which is secured by its other end to a rocking shaft 79, the shaft 79 being supported at either end by brackets 80.

As shaft 79 is rocked the plunger 76 moves up and down and swings about its pivot 77 towards and away from the edge of the stack pile as a result of the engagement between. a cam surface 81 provided on the forward edge of the plunger and a fixed abutment surface 82. A spring 82:: maintains the cam surface 81 in contact with the surface 82.

Also freely mounted on the rocking shaft 79 is a bracket 83 which carries a micro-switch 84 the contacts of which are connected in the circuit of the electric motor controlling the movement of the platform 74. The bracket 83 is mounted intermediate its length on the rocking shaft 79 and is provided with a stop pin 85 which engages with the edge of an arm 86 keyed to the rocking shaft 79. The stop pin is maintained in engagement with the arm by a tension spring 87 the opposite ends of which are anchored to the brackets 83 and arm 86 respectively.

The bracket 83 is coupled by a link 89 to one end of 'a rocking arm 90 the other end of which is keyed to a short spindle 91 mounted in a bearing 92 carried on the lower end of a bracket 93 extending downwardly from the supporting framework of the discharge conveyor.

The short spindle 91 is connected by 'a universal ball joint 94 to one end of a telescopic drive shaft 95, the other end of which is coupled by a further universal ball joint 96 to a further short spindle 97 carried on the lower end of the aforementioned bracket 55. The short spindle '97 is rocked through an arm 98 which is secured by one end to the short spindle, the free end of the arm being connected by a link 99 to the crank pin 100 of an eccentric mounted on so as to be rotatable with the previously mentioned shaft 21.

With the above described arrangement when the sheet pile is below the predetermined level the plunger 76 moves freely into and out of the detecting position due to the rocking motion imparted to the rocking shaft 7-9 through bracket 83, arm 86 and the linkage to the eccentric crank pin 100. When, however, the sheet pile has reached a level at which the upper edge of the pile is in the path of movement of the plunger 76, the free movement of the plunger 76 is restrained and the rocking shaft and conse-- quently the arm 86 are also held against movement. The bracket 83 is however free to continue its movement against the action of spring 87 with the result that the button 88 of the micro-switch 84 is brought into contact with the arm whereby the micro-switch is closed to complete the circuit to the electric motor which operates to lower the platform 7 4. The circuit of the electric motor isinterrupted automatically when the'restriction onthe plunger'76-has been removedwhercby1thebracketf83 and arm 86 canbc-returned to the normalposition-by tension spring87'when-the plunger-76is again out of engagement with the *sheets,

When the mechanism of the present invention is utilised for the :delivery ofprinted sheets, printed side uppermost, to 'a-staclc pile,--means-are for preferenceprovided at the delivery end of thebelt conveyor for discharging a sheet Ontothe'pilein suchmanncr thatthe same will not scratch, scrape or otherwisc' damage the exposed surface or the top sheet on the stack.

Ithas been found that if-leach sheet as it leaves the belt conveyor is stiffened by, for example, bowing the same upwardlyacross its width, i. e. in a direction transversely of the conveyor beltthe leading edge of the sheet is prevented from sagging whereby the same as it is dis charged, would scrapeacross the surface of the previously discharged sheet.

For the above purpose the sheet when it reaches the discharge end of the-belt conveyor is caused to pass beneath a pair of upper rollers-101 each of which is mounted so as to be freely rotatable on a common shaft 102. The rollers 101 are disposed one on either side of the belt carrying pulley S8 and as a sheet 8 passes between the rollers 101 and the-pulley 58 it assumes a curved form as shown-in Fig. 6.

I claim:

' 1. In sheet ceding mechanism having a substantially horizontal endless main conveyor with spaced tray-s thereon renr-wardly inclined with respect to the direction of conveyor travel for transporting sheets on edge in spaced relationship on the upper run thereof, means for removing the sheets in spaced relationship from said main conveyor atthe delivery end of its upper run comprising a lower auxiliary endless conveyor adjacent said delivery end and having the same direction of travel as said=main conveyor, meanssecured in spaced relationship togsaid lower :auxiliary conveyor for-engaging the lower edges of the sheets, said-lower auxiliary conveyor being arranged with respect tosaid main conveyor to receive said sheets at the delivery height of said main conveyor and to transport the sheets upwardly and forwardly relative to the main conveyor until clear of said trays, an upper auxiliary endless conveyor above and spaced from said lower auxiliary conveyor and travelling in a direction opposite to the direction of travel of said mainand lower auxiliary conveyors, and members secured to said .upper conveyor in spaced relationship so that during the lower run of said upper conveyorsaid members serve tosupport the sheets-to maintain a rearwardly inclined disposition thereof while travelling forwardly upon said lower ;auxiliary conveyor.

2. Sheet feeding means as defined in claim 1 wherein said conveyors are driven in synchronism.

3. Sheet teedingxrneansasdefined in claim 1 wherein the upper run of said lower auxiliary conveyor base portion or. travel of relatively steepupward inclination adjacent said main conveyor and ,aportion of travel of relatively gradual upward inclination adjacent said steep portion.

4. Sheet, feeding means asdefined in claim 1 wherein the members secured ,to said upper conveyor are forwardly inclined With respect to the direction of conveyor travel sothat they are substantially parallel to the trays of the main conveyor.

References Citedin-the file'of this-patent UNITED STATES PATENTS 3,374,981 Boughton Apr. 19,'l92l 1,468,181 Wagner Sept. [8, 1923 1,504,73i WigglesWorth Aug. 12, 1924 l,920,563 Jahne Aug. 1, 1933

Images