GB1202168A - A sewing machine provided with a pressure lubrication system - Google Patents

Abstract

1,202,168. Lubricating. VIRGINIO RIMOLDI & C. S.p.A. 30 July, 1968 [13 Sept., 1967], No. 36346/68. Heading F2A. [Also in Division D1] A sewing machine is provided with a lubrication system comprising a pump unit 21, Fig. 1; a delivery pipe 26, which is connected to a dome 27 of transparent material; a pressure switch 39, which is connected by a pipe 40 to the delivery pipe 26 and which is opened by the pressure of the lubricant passing through the delivery pipe, the switch 39 being closed by spring means when the pressure in the delivery pipe 26 becomes a pre-determined minimum value. The closing of the switch lights a warning lamp 45. A delay is provided to prevent the lamp 45 from lighting during short interruptions of operation of the sewing machine. The switch 39 comprises a support 46, Fig. 3, of insulating material and a cover 47 which are connected together by means of rivets 48. A hollow cylinder 49, Fig. 6, is positioned between the support 46 and the cover 47 and contains a piston 50, the diameter of which is made small enough to allow lubricant to pass between the cylinder 49 and the piston. The cylinder 49 has a closing diaphragm 51, having an integral pipe 52 connected to the pipe 40 and having an entrance aperture 53 internally closed by a valve 54. The electric circuit for the lamp 45 comprises a bulb holder 58, electrical terminals 63, 64, the cylinder 49, the piston 50, a contact 67 which is mounted on a piston-rod 57 of the piston 7, a plate 66 and cables 70, 71. The pressure of the lubricant forces the piston 50, Fig. 6, against a wall 55, thus closing a square-shaped aperture 56 therein and disengaging the contact 67 from the plate 66. When the pressure of the lubricant is in sufficient to compress a spring 73 which is located between an end-wall of the piston and the wall 55, the piston is urged towards the diaphragm 51, the valve 54 is closed, and the movement of the piston is retarded by means of the lubricant in the cylinder 49 slowly escaping therefrom through the squareshaped aperture 56 in the wall 55. When the cylinder is empty, the contact 67 engages the plate 66 and the lamp 45 indicates that the pressure of the lubricant is too low. A filter 29 is provided for the lubricant which is returned to a reservoir 20, and a felt 32 and a pipe 34 connect to the pump means 21 to recover lubricant from a head 31 of the sewing machine.