GB929484A - Conveying and stacking apparatus - Google Patents

Abstract

929,484. Delivering sheets. MULLER A.G. Aug. 25, 1960 [Aug. 28, 1959], No. 29441/60. Class 100 (1). A machine 1 applies glue to a band of veneer 4 which is then cut into short lengths by a shearing device 2. A pair of horizontal, parallel girders 5, 5a is mounted above the apparatus 1, 2, the girders being mounted so as to be longitudinally slidable on bearings such as 8 mounted on a cross-member 50 and on top of the machine 1. Each girder is hollow and has a number of tubular arms 27 pivotally mounted in bushes therein, the interior of the girders communicating with the interiors of the arms when the latter are in a substantially vertical position. The arms 27 carry at each end suction cups 32 each of which communicates with the interior of its arm when a valve in the cup is opened. The valves are opened by means of feelers projecting downwards from the centres of the cups 32 when the cups are pressed into contact with the veneer 4 as described hereafter. Suction is applied to the interior of the girders by means of suction producers 39 controlled by electromagnetic valves 64. Rails 40 are mounted at each side of the girders 5, 5a, and are engaged by lateral pins 41 carried by the arms 27 so that when the girders are in the retracted position, as the girder 5a is shown, the arms 27 are raised into an inclined position out of engagement with the veneer band 4. The band 4, which, as shown, is of half the width which the machine is capable of taking, is fed from the machine 1 between the blades 52, 54 of the shearing device 2 and thereafter rests on pivoted arms 85 in the dotted line position of Fig. 5. Chains 21 are mounted on the upper sides of the girders 5, 5a and form racks which are engaged by sprocket wheels mounted in gear-boxes 17 secured to a cross-member 16. By means of a system of clutches in the gear-boxes 17 the driving sprockets may be driven from the machine 1, in which case the girders move in the direction of the arrow 48 at a speed slightly in excess of that of the band 4, or from a motor 23, in which case the girders are moved at a relatively higher speed in the direction either of the arrow 48 or the arrow 46. When the leading end of the band 4 emerging from between the shearing blades reaches the far end of the arms 85 it actuates a switch 57 whereby the drive of the girder 5 is clutched and the girder is advanced in the direction 48 at its low speed, the girder 5a being put out of action when the band is of this width. As each arm 27 assumes a vertical position a rail 86, Fig. 5, on the girder actuates a valve 19 in the circuit of a pneumatic cylinder 82, whereby the arms 85 are momentarily moved to their full-line position. Such movement presses the veneer 4 into engagement with the suction cups 32 on the arm 27 where it opens the valves in the cups and is held by the suction exerted by the device 39. As the forward speed of the girder 5 is slightly greater than that of the band 4 the arms 27 eventually assume a rearward trailing inclination which causes levers 59 carried thereby to actuate switches 60 mounted on the girder. This has the effect of declutching the girder drive. As soon as the band 4 " catches up with " the girder the arms 27 resume their vertical position, the levers 59 are disengaged from the switches 60 and the girder is again driven. When a predetermined length of veneer has been fed between the shear blades a veneer measuring device associated with the device 2 actuates the latter, so that the length of veneer is cut off the band, and simultaneously triggers off three delayed action relays, the first of which 0.8 second after the cut causes the girder 5 to change over to its faster speed in the direction 48. The second relay actuates the electromagnetic valve 64 1.5 seconds after the cut so that suction is cut off from the cups 32 and the cut piece of veneer is dropped on a stack, and simultaneously reverses the direction of high speed movement of the girder. On reaching the retracted position the girder is halted by means not shown, and the third relay, 3.5 seconds after the cut, restores the valve 64 to its initial position in which suction is applied to the interior of the girder. When the cut end of the band 4 reaches the switch 57 on the arms 85 the cycle recommences. If the band 4 is double the width shown both girders are used in unison. Two parallel bands of the width shown issuing from the machine 1 may be stacked by the device shown, the girders then working independently and the blade 52 being in two separately operable parts. In a modification, Fig. 13, the suction cups 32 are replaced by electromagnets 102. Drums 106 are mounted beneath the arms 85 in alignment with the longitudinal rows of electromagnets 102. Each drum 106 contains a coiled band of spring steel 107 which is spring biased towards a position in which it is coiled within the drum. The outer ends of the bands 107 are prevented from being retracted into the drums by a bar 108 secured to the free ends of the arms 85. A cycle is initiated as in the previous embodiment by the switch 57. As each arm 27 attains a vertical position a trigger 103 carried thereby actuates a switch 101 which energizes the magnets on that arm; simultaneously the arms 85 lift the veneer 4 and the bands 107 underlying the veneer into engagement with the magnets. After a sheet of veneer has been cut and carried to the limit of the girders' travel the current to the magnets is cut off and as the sheet falls on to the stack the bands 107 are retracted into the drums 106 until the outer ends of the bands engage the bar 108 again. In either embodiment the cutting off of suction or magnetic support for the sheet may be effected in a stepwise fashion along the length of the sheet rather than at all the relevant arms 27 simultaneously.