GB173469A - Improved mechanism for converting rotary into reciprocatory motion - Google Patents

Abstract

173,469. Tekniske Forsogsaktieselskab. Dec. 31, 1920, [Convention date]. Addition to 158,228. Machinery, utilizing inertia to obtain move. ments in.-Relates to a modification in the means for converting rotary into reciprocating motion described in the parent Specification, and consists in providing weights carried at the outer extremities of each arm or two or more arms of a system of rotatably. driven jointed arms, the lengths and directions of rotation of which, and the mass of the weights, are preferably such that the centre 0f gravity of the system oscillates in a straight line or in a closed curve approximating thereto. In the simplest form, Fig. 4, a weight O1 is carried at the joint W2 between the oppositely-driven arms S1 S2 and a weight O2 at the end of the arm S2; when L2=2L1 and the mass O1=the mass O2, the reactive force on the body V has no lateral component. By vary. ing the relative moments of the weights O1, O2, small lateral components may be introduced, as required, e.g. in the application to the wings cf ornithopters. The number of arms and weights may be multiplied, as shown in Fig. 6, which discloses three arms S1, S2,. S3. In place of the chain drive described in the parent Specification, a pinion (not shown) rigid with the arm S2, Fig. 4, may mesh with an internally toothed wheel concentric with the pivot W1, or, through an idler journaled on the arm S, with an externally-toothed wheel. In the arrangement diagrammatically shown in Fig. 12, the arm S2 is driven by a connecting-rod T2 and a crank T, rotating in the direction of the arrow. The crank T1 may be extended and the connecting-rod T2 replaced by a pin-and-slot connection with the arm S2. These arrangements are stated to be applicable also to the form shown in Fig. 6. The arms and weights may be combined in the form of eccentrics O1, O2, Fig. 13, an arrangement suitable for driving hammers, wherein a short stroke is desired and heavy shocks arise. The eccentric O1 may be driven by bevel-gears G, F, and the eccentric O2 in the opposite direction by bevel-gears G, E through one or more (say four) crank-like links T2, having preferably a. throw x equal to the eccentricity. The Specification as open to inspection under Sect. 91 (3) (a) comprises also the following subject-matter : The eccentrics may be formed with lead-filled chambers to increase their effective mass. As applied to hammers, the arrangement may be duplicated, Fig. 14 (Cancelled), in order to apply symmetrical forces to the tup V, the elements being then interconnected trough a hollow shaft W1 To reduce shock, the drive to the arms or eccentrics may be spring- cushioned. A form is described in which the arms are approximately or exactly equal, and a weight is carried at the end of the outer arm only. This subject-matter does not appear in the Specification as accepted.