GB291632A - Improvements in and relating to crank mechanism for driving reciprocatory parts - Google Patents

Abstract

291,632. Johnson, J. Y., (Link-Belt Co.). July 12, 1927. Crank - actuated pumps; counterbalances; stroke, varying.-In mechanism for driving oilwell pumps, drills and like apparatus having relatively heavy reciprocating parts, a counter balancing weight or weights are secured to the periphery of a crank disc or sector on the driving shaft, the weights being adjustable circumferentially to regulate the degree of unbalance and the lead or lag thereof in relation to the crank pin. The crank throw and the angular disposition of the crank on the shaft are adjustable without disturbing the setting of the counterweights. The weights may be carried by a rim or saddle which is readily detachable from the crank member and may be supported in proximity thereto ready for re-attachment when required. The driving unit shown in Fig. 1 comprises an electric motor or other prime mover with reduction gear in a casing 1, the shaft 2 carrying a crank disc 3 with spaced radial sets 4, 5, 6 of holes 7 in any of which the crank pin 8 may be secured by a nut on the threaded end thereof. Counterweights 17 are secured to the crank disc by headed bolts 12 in an undercut peripheral groove 11, lugs 16 on the weights entering the groove. Three or more weights may be provided, the maximum counterbalance being obtained when they abut as shown and the effect being reduced as they are disposed more or less symmetrically around the shaft. In the arrangerrent shown in Fig. 9, the weights 33, 34, 35, are secured by bolts 32 in a T-grooved saddle piece 19 secured to the crank disc 3 by pivoted tie-bolts 21, located in peripheral slots 22, and clamped by nuts 23, 27 which engage seatings in recesses 24 in the disc. Brackets 38, 39 on the adjacent framework are formed with holes to receive bolts 42 which may be passed through elongated slots 36, 37 in the saddle when suitably located. When thus positioned, the saddle may be lowered on to the bolts and disconnected by unscrewing the nuts 23, 27. While out of use, the tie bolts 21 are secured by pins 44 passing through lugs 43 on the saddle. An alternative arrangement for supporting the saddle when disconnected comprises a cradle or frame 48, Fig. 12, with a circular track 49 upon which the counterweights rest when lowered therein by releasing the tie bolts 21. A gap is provided in the retaining flanges 52 to facilitate removal of any of the counterweights.