324,140. Turner, Ltd., S., and Plint, A. F. Oct. 29, 1928. Cow-milkers. - A pulsator for milking machines of the type comprising a pair of diaphragms of different superficial area arranged in a casing in which the smaller of the diaphragms is open on one side to atmosphere, the closed space between the two is constantly evacuated, and the space between the larger diaphragm and the casing is intermittently exhausted, is characterized by the provision of a single valve connected to and operated by the diaphragms to produce pulsations in the teat cups and in the space between the larger diaphragm and the casing. To the top of a cylindrical casing 1, Fig. 1, of cast iron or other material, a light diaphragm 3 of rubber, rubberized fabric, flexible metal, or other material is secured by an annular collar 5, which is surmounted by a similar but imperforate and larger diaphragm 6 and secured by a flanged head 8 : the whole being packed and secured by stud bolts 9. A small head 18 is secured in an airtight manner to the underside of the diaphragm 3 by a bolt 19 which also passes into a dumb-bell connector 30 between the two diaphragms. Levers 24, 25 pivoted on the head 18 are joined by a tension spring 26 and carry rollers 27, 28 respectively, these rollers engaging the head of the valve 17. The substantially circular cavity 2 is open to the atmosphere as, for example, through an aperture in the wall of the casing, and the space between the two diaphragms is constantly evacuated through the suction supply pipe 10 and the conduit 12. The valve 17 has a central bore 30 open to the annular cavities 32, 33 and to the atmosphere through the sole 37 which limits the travel of the valve. When the pulsator is in the position shown in Fig. 1, suction from the pipe 10 is applied to the space between the diaphragms, to the space 44 through the conduit 13, the annular cavity 40 in the valve, and the conduit 42, and to the teat cups 51. Air is admitted to the teat cups 52 through the bore 30, the annular space 33, and the conduit 45. Owing to the relatively high pressure in the space 2, the diaphragms move upwards and cause the rollers to travel upwards over the head of the valve. As soon as the rollers pass the peak 46, the valve is forced downwards into its lower position where suction is cut off from the space 44 and applied to the teat cups 52 through the conduit 13, the annular space 40, and the conduit 45. Air passes up the bore 30, out through the upper port into the annular space 32, to the conduit 42 and the space 44, and to the conduit 41 and teat cups 51. As the area of the diaphragm 6 is greater than that of the diaphragm 3, the total pressure on the upper diaphragm will be greater than that on the lower, and the two will move downwards, whereby the valve 17 will be returned to its upper position as soon as the rollers have passed over the peak 46. The cycle of operations will be repeated so long as suction is applied to the pipe 10. The speed of operation can be adjusted by varying the bore of the conduit 42 or by providing a suitable valve therein. In a modification, Fig. 4, the valve is constituted by a sliding member 17a in a seating 15a. A roller 27a on the end of a rocking lever 25a is maintained in abutment against the cam surface of the valve by a spring 26a enclosed between a collar 32a and the bushing 30a. The lever is connected to the head piece 18a of the diaphragms by a link 24a and is mounted in a bushing 30a, say of bronze, which is screwed into the casing and has a conical bearing 31a to allow vertical movement of the lever. As before the space between the diaphragms is constantly evacuated, and with the valve in the upper position, as shown, the suction pipe 10a is in communication with the teat cups and the space, 44a through the conduit 13a, the valve port 40a, and the conduits 41a, 42a respectively. As the diaphragms rise, the roller rises and rides over to the upper declivity of the surface of the valve which is thereby forced into its lower position. Suction is now applied to the teat cups through the valve port 40a and conduit 45a and the diaphragms will be lowered so that as the cycle of operations is repeated, pulsations of the diaphragms and in the conduits 41a, 45a will be produced. By omitting the conduit 41 or 41a, the apparatus could be used with a single suction conduit applied to the four teat cups. A teat cup, Fig. 3. comprises a cup-like member 51 preferably of rigid material such as vulcanite or metal surrounding a rubber sleeve 49 terminating in a, milk pipe 50 which is subject to suction. According to the Provisional Specification, the distance piece between the diaphragms may be extended and connected to the lever 25a, the lever may be controlled by gravity action, and the valve may be of cone, rotary, or other type.