GB1460986A - Rotary crank press - Google Patents

Abstract

1460986 Converting rotary to reciprocating motion; eccentrics AIDA ENG KK 7 Aug 1974 [10 Aug 1973] 34759/74 Heading F2K In a mechanism for converting rotary motion to linear reciprocating motion, a driven shaft 1 rotating on a fixed axis Z has an integral eccentric portion la, engaged rotatably in an eccentric sleeve 2 which in turn is rotatably carried within a slider member 3, this slider member being constrained by guide means 4<SP>1</SP>, 4<SP>11</SP>, which permit reciprocating movement in a direction perpendicular to the shaft axis Z. The guide means may consist of integral side members 4 having faces 4<SP>1</SP>, 4<SP>11</SP> projecting from a bearing block 4a in which shaft 1 is journalled. In Fig. 1, centre B of the eccentric portion la is caused to orbit around a fixed centre A of shaft 1, while the centre C of the periphery of sleeve 2 is constrained to travel solely along the vertical centreline through A. Sleeve 2 is not driven in rotation by any means other than the "squeezing" action imposed on it between the eccentric portion la and the bore of slider 3. From an initial position as shown in Fig. 1, with centres A, B and C aligned upwards, the first 90 degrees of rotation of shaft 1 in the direction P induces a motion of sleeve 2 in direction Q, reversing to direction Q<SP>1</SP> during rotation from 90 degrees to 270 degrees, and reverting to direction Q from 270 degrees to 360 degrees, and centre C travels in direction X during shaft rotation from 0 degrees to 180 degrees, reversing to direction Y from 180 degrees to 360 degrees. In an alternative embodiment, Fig. 4(a), the centre A<SP>1</SP> of shaft 1 is located in a vertical plane laterally offset from the verti. cal plane through centre C. This modified motion provides a downward travel of centre C in direction X which may be prolonged over approximately 210 degrees of shaft rotation, with a faster return travel in direction Y to complete the cycle. A mechanism having either of the alternative embodiments may be incorporated in a press, in which the slider 3 may be formed integrally with the press ram member 10, Fig. 6 (not shown), or alternatively the slider 3 may be provided with a threaded bore carrying an adjusting screw 13 coupled to a separate press ram member 10, Fig. 8.