Patent GB-329735-A (GB)
Title: Improvements in machines for forming containers from plastic material
IPC: D21J3/00
Filed: 1929-03-08
Abstract: 329,735. McArdle, F. W. March 8, 1929. Moulding pulp.-In a machine for forming receptacles such as caskets, baths, &c. from wood or other liquid pulp having a foraminated former 38 and platens 26, 27, 28 movable towards and awav from the former the platens are each actuated by a separate hydraulic ram and toothed gearing connects all the rams so that the platens are uniformly advanced, depositing walls of equal thickness. The foraminous former 38 is surrounded at the sides and top by perforated platens 26, 27, 28 slidable in chambers 23, 24, 25 and operated by rams 30, 31, 32 secured to the bed-plate 20 and cover plate 21. Racks 57 rigid with the rams mesh with pinions 53 - - 56 on shafts 45 - - 48 operatively connected by bevel gears 49, 50, 51 and a countershaft 52. The pulp valve A adapted for continuous circulation of the pulp comprises a seating 66, Fig. 5, secured to the wall of the chamber 25, a casing 65 supplied with pulp through a pipe 67 and a return pipe 68 through which the pulp may pass back to the source of supply when the plunger valve 70 closes the entrance to the chamber 25 as shown. The valve may be shifted by a handle 79 to close the return pipe 68 and allow the full capacity of the inlet pipe 67 to discharge into the chambers 25, 24, 23. After the shell has been formed and the platens 26, 27, 28 retracted the supporting platen 33 is freed from locking connection with the bed plate 20 by retracting bars 34 from grooves 340 in the bed plate, the bars 34 being linked to crank plates 35, Fig. 4, linked to a plate 36 operated by a lever 37. A three-way valve 89 is then turned to permit the hydraulic ram 86 carrying the supporting platen 33 to descend, the water from the cylinder escaping through a pipe 90 to the waste main 44. During the descent a stripper 39 on which the formed shell B rests engages ledges 103 on opposite frames 102, Fig. 8, the ram with the platen 33 and foraminous former 38 continuing to descend, and as it reaches its lowest position a pawl 170, Fig. 11, on the platen engages a lever 174 to turn a valve 147, starting 'the transferring mechanism. As soon as the former 38 has descended clear of the path of movement of the stripper 39 the operator lays a wooden rack C on the shell B, which has been moulded bottom upwards. The valve 147 supplies water from the hydraulic pressure main to a cylinder 141 in which reciprocates a ram 140 connected with parallel radius levers 95, 96 pivoted to beams 100 carrying pivotally at 104 the frames 102. Normally the lever 95 rests against an abutment 106 and at the start of the swinging movement the arm 112, Fig. 8, of a dog 107 pivoted at the lower corner of the frame 102 leaves a stop 115 allowing it to be turned by a spring 114 to clamp the stripper 39 to the frame 102. A link 110 connects the dog 107 to a similar dog 109 at the other side of the frame which is thus also operated to clamp the stripper 39. As the swing- ing movement continues a lever 122 pivoted to the frame 102 is turned by a swinging abutment 127 into a horizontal position operating through links 121 dogs 116, 118 having blades 125 to clamp the wooden rack C to the shell B. In the clamping position the lever 122 and links 121 are in dead-centre position. Rigid with the trunnion 104 of the frame 102 is a three-armed element 130 the arms of which successively engage abutments 131, 132 on the standard 99 to rotate the frames 102 with their load through 180‹ at the end of the swinging movement. A stop 134 on the support or truck 133 acts on the left-hand lever 121 to release the dogs 116, 118, depositing the rack C and shell on the support. The motion of the radius arms 95, 96 is then reversed, the valve 147 being turned to reverse the ram 140 by a link 155 pivoted to an arm 154 rigid with the shaft 97 of the radius arm 95. In the return movement the element 130 reverses the frame 102, the lever 122 swings the abutment 127 about its pivot and the stop 115 finally releases the dogs 107, 109. The valve 89 is then turned to raise the supporting platen 33 which in its upward movement picks up the stripper 39 from the ledges 103 and when returned to the normal position is locked by operating the lever 37. The return movement of the radius arms also closes the valve 147 by a link 156 pivoted to the arm 154. During the upward movement of the platen 33 the pawl 170 swings past the lever 174 of the valve 147. The reversing valve 147 is always turned in the same direction, the links 155, 156 being provided with pawls 149, 150 acting on a ratchet wheel 148 rigid with the valve plug and the lever 174 being duplicated at the opposite side, at 174<a>. To continue the swing of the radius arms 95, 96 when the ports in the valve 147 have been closed, the movement of the slotted lever 164 connected to the ram stem 160 is transmitted to the shaft 97 through springs 168 between extensions 167 of the lever 164 and a projecting lug 166 on the shaft 97. The springs 168 also cushion the parts at the ends of the travel. To prevent rocking of the frame 102, a leaf spring on the beam 100 bears against the frame. The truck or support 133 may be transferred to a drying kiln. The rams 30, 31, 32 are returned -to starting position by a counterweight 60 on a cable 59 secured to a sheave 58 on one of the gear shafts.