Title

Man Working a Treadle Grindstone

Description

[The diagram] shows that in operation, ‘the body of the worker becomes kinematically chained with the machine’ (1876: 500) – in other words the worker is as much a part of the machine as is the work-piece. Now if we disregard what the man is doing with his hands and arms, and the object he holds, the stone itself could be treated as the work-piece, and the whole machine as a place-changer designed to secure the rotation of the stone. From the diagram it can be seen that the machine operates through the kinematic conjunction of two lever cranks. One crank is formed by the links a, b and c, secured at points 1 and 4 by the fixed frame d. The other crank, which drives the first, is formed by the links a′, b′ and c′, secured at points 1′ and 4 by the fixed frame d′. There is no difference, in principle, between the artificial coupler b and the shinbone b′, nor between the frame d, built into the structure of the device, and the frame d′, formed through the posture of the man. As this example demonstrates, the machine is not external to the worker, ‘receiving’ from him its motive force, for in reality ‘the worker makes a portion of his own body into a mechanism, which he brings into combination, that is chains kinematic-
4 ally, with the mechanism to be driven' (1876: 501).

Designer

Reuleaux, Franz

Date

1876

Source

Ingold, Tim. (2000). The perception of the environment: Essays on livelihood, dwelling and skill. Routledge.

Bibliographic Citation

F. Reuleaux, The kinematics of machinery, published by Macmillan, 1876, p. 501.

is composed of

English Circle

English Triangle