Patent GB-859242-A (GB)
Title: Improvements relating to liquid dispensing machines
IPC: B65B3/32
Filed: 1959-02-05
Abstract: 859,242. Bottling. ROCKCOTE PAINT CO. Feb. 5, 1959 [Feb. 24, 1958], No. 4125/59. Class 125(2). [Also in Group XXVIII] A liquid dispensing machine particularly for paint comprises a number of reservoirs 40 rotatably mounted so that any one of them can be moved to a dispensing station, and pumps 11 each associated with a reservoir and having a reciprocating piston therein to dispense a measured quantity of liquid. The canister comprising the reservoirs is rotatably mounted in bearing 28 and supported on rollers 34 and is turned by a motor via chain and gear wheel 129. Screens 46 filter liquid flowing to the pumps. In operation, when a particular liquid is to be dispersed the canister is rotated until the reservoir containing this liquid and its associated pump are brought opposite the dispensing station. The head 56 of the piston rod is then engaged by the jaw 81 which is reciprocated by the double-acting fluid operated piston and cylinder mechanism 12 to force liquid through the nozzle 64 of the pump. This nozzle incorporates a ball and spring valve which is released when the liquid in the pump is put under pressure by the operation of the piston which also includes a valve which opens when the piston is raised to allow liquid to flow into the pump cylinder 51. The movement of the jaw 81 is restricted by a cam plate 95 which can be rotated to give different lengths of movement to the jaw and therefore the pump piston so that different quantities of liquid may be dispensed. A spring 85 ensures that the jaw is disengaged from the head of the piston rod when the dispensing operation has been completed. The dispensing operation is controlled automatically by an electric control circuit which is such that when the switches C and S have been set the canister is rotated until a microswitch M corresponding to a particular reservoir is operated by arm 131 mounted to rotate with the core 39 of the canister. This switches off the drive to the canister and also applies a brake consisting of a pivoted latch arm. However, to ensure that the microswitch does not remain in the " on " position it is overrided by a jig switch 211 operated by the pump cylinder 51 which delays the switching off of the drive and the applying of the brake for a short interval until the microswitch is in the off position. When the canister stops a hydraulic motor 111 is energised to operate the mechanism 12 via conduits 116 and 117 so that the jaw 81 moves until the arm 105 strikes the cam plate 95 whereupon the pressure builds up in conduit 116 to operate a pressure switch 121 to reverse the motor and withdraw the jaw and pump piston to complete the dispensing operation. The filler caps for the reservoirs comprise a vent hole and a wad of an absorbent material impregnated with a mixture including an anti-oxident for maintaining a protective atmosphere in the reservoir. Stirrers 222 for the liquid in the reservoirs are rotated by a fixed band 226 engaging pulleys 225. A device for wiping the nozzles after use comprises a roller which engages the nozzle and a bath of solvent into which the roller rotates.