742,486. Liquids proportioning and dispensing apparatus. AVERY-HARDOLL, Ltd. March, 31, 1954 [Feb. 19, 1953], No. 4717/53. Class 86. [Also in Groups XVIII and XXVIII] A liquid measuring and dispensing apparatus for dispensing a predetermined quantity of a mixture of two liquids in a predetermined proportion, comprises in combination a primary reciprocating pump calibrated to deliver at each operation a quantity of one liquid equal to the predetermined quantity, a secondary reciprocating pump adjustable to deliver simultaneously a selected smaller quantity of the second liquid, and a receiving chamber separate from said pumps, said receiving chamber being adjustable with the secondary pump to receive from the primary pump during the dispensing operation, a quantity of liquid equal to that delivered by the secondary pump. An apparatus for delivering petrol mixed with one of three different grades of oil includes a petrol pump cylinder 16, Figs. 3 and 4, and three oil pump cylinders 26, 27 and 28 each for a different grade of oil, equally spaced around a chamber 29. A piston 17 in the cylinder 16 is connected by a rod 22 to an air pressure motor cylinder 21 which moves over a fixed piston 23 to impart a single working stroke to the piston 17 in response to rotary displacement of a control knob 59. The knob 59 is attached to a spring-biassed shaft 58 carrying a cam arm 57, Fig. 7, which normally opens an outlet valve 56 in the piston 23, and when the shaft 58 is rotated, opens an inlet valve 55. During the working stroke of the motor the cam 57 is retained in engagement with the inlet valve 55 by the engagement of a cam track, Fig. 6 (not shown), on the air motor cylinder, with a cam follower secured to the shaft 58. At the end of the working stroke the cam and cam follower disengage, permitting the shaft 58 to spring back to the position in which the cam 57 opens the outlet valve 56. The return stroke of the piston 17 is effected by a spring 25. The chamber 29 contains a piston 39 on a piston rod 41 which is coupled to the air motor cylinder 21 by a lever 45 pivoted at 46. Each of the cylinders 26, 27, 28 contains a piston 37 on a piston rod 34 formed with a head 35 notched at 36 and the piston rod 41 is coupled to one of the piston rods 34, selected according to the grade of oil required by means of a quadrant arm 42, Fig. 4, secured to the piston rod 41 which is brought by rotation of the piston rod 41 to engage the notch 36 in the head 35 of the selected piston rod 34. The piston 39 and the selected piston 37 have equal lengths of stroke and they move in unison with the piston 17, but the length of stroke of the pistons 39 and 37 is selected to provide any one of four different petrol oil ratios by adjusting the point of connection between the piston rod 41 and lever 45 to one of four pegs 49, 51, 52, 53 spaced along the lever 45. For this purpose three equally spaced radial arms 43 having notched ends are fixed to the piston rod 41 which can be rotated to a position wherein any selected one of the pegs 49, 51, 52 or 53 is engaged by the notched end of one of the arms 43 whilst the quadrant 42 engages the selected one of the piston rods 34. The space in the cylinder 29 behind the piston 39 is connected through a conduit 54 with the cylinder 16 and during each working stroke of the piston 17 this space takes from the petrol pump a volume of petrol equal to the volume of oil delivered from the selected oil pump cylinder 26, 27 or 28, so that the total volume of mixed liquids dispensed by the petrol pump and the selected oil pump is equal to the volume of petrol pumped from the cylinder 15, this volume being calibrated by adjusting a stop 18 to control the length of stroke of the piston 17. The piston rod 41 is slidable in but non-rotatable with respect to a tubular shaft 63 carrying a setting knob 64 and dial 65 by means of which the rod 41 can be turned to select the grade of oil and the proportion to be dispersed. A slidable rod 67 co-operates at one end with a cam 69 carried by the air motor control shaft and at the other end with a disc 66 having twelve edge notches carried by the tubular shaft 63 whereby the air motor can be set in operation only if the shaft 63 is properly set to one of its twelve operative positions, and the setting of the shaft 63 cannot be altered once the air motor has been set in operation. Reservoirs for the petrol and the three grades of oil contain floats having rods 83, 85, 86 and 87 respectively which normally support pivoted fingers 84, 88, 89 and 91. The underside of each finger is notched to engage a lug 93 carried by the air motor control shaft 58. In the event of the supply of petrol or the supply of any grade of oil selected by the setting of the shaft 63 falling below a predetermined level in the reservoir, the corresponding finger falls to lock the shaft 58 and prevent operation of the air pressure motor. Each working stroke of the apparatus must be initiated by an actuation of the knob 59, and the total quantity of mixture delivered is shown by an indicating drum 72 rotated by means of a ratchet wheel 73 driven by a pawl 74 on the lever 45 and held until released by actuating a plunger 77 of a zeroing device. The petrol delivered from the pump passes through a conduit 96 into a well 97 at one end of an elongated narrow mixing chamber 98 having three oil chambers 99, 101, 102 extending completely across it and each connected to one of the cylinders 26, 27, 28 and opening through a small orifice 103 into a horizontal channel 104 connecting the well 97 to a well 105 from which the mixture is discharged through a hose 13. One side of the mixing chamber is transparent.