GB1282385A - Cyclically operable machine - Google Patents

Abstract

1282385 Sewing machines NECCHI SpA 13 April 1970 [23 April 1969] 17403/70 Heading DIG [Also in Division F1] A sewing or other cyclically operating machine comprises a first pneumatic ram 29 coupled to a cycle initiating means 30 and a second pneumatic ram 44 coupled to a workpiece clamp 46 each ram being connected to a pneumatic circuit via a respective adjustable inlet valve, (27 or 42) and quick exhaust valve (28 or 43) in series. A buttonhole or other sewing machine is shown at the end of a cycle in Fig. 2 where a treadle 23 is in its raised or released position holding open the valve 19 to supply air to the ram 44, thereby raising the workpiece clamp 46, via a valve 36, which is opened by one arm of a lever 32, an open valve 39 which is controlled by a cam 40 which rotates once in an operating cycle of the machine and the valves 42, 43. The machine is locked in the stop position by engagement of a projection 47 on the lever 32 with a tooth 34 of a cam wheel 35. On depression of the treadle 23 first the valve 19 closes permitting the quick exhaust valve 43 to exhaust the ram 44 to lower the clamp 46 and then the valve 18 is opened supplying air to the ram 29 which rotates the cycle initiating lever 30 and hence the lever 32 to disengage the projection 47 from the tooth 34 and start the sewing cycle. Should the treadle be released the ram 29 will be exhausted but the machine continues sewing until the projection 47 on the spring loaded lever 32 again engages the tooth 34 of the cam wheel 35. The clamp 46 remains down until the cam 40 rotates to open the valve 39 at the end of the complete cycle thus allowing compressed air to reach and operate the ram 44. An emergency stop button may be provided to stop the machine during a cycle, the clamp remaining down so that the machine may continue the cycle when required to.