The Commercial Revolution of the Middle Ages 950–1350: THE UNEVEN DIFFUSION OF COMMERCIALIZATION

A recorder for recording a sensed condition on a strip of flexible recording medium. The recorder includes a housing with a support member which releasably supports a coiled up portion of the strip for rotation relative to the housing. A take-up member rotatably connected with the housing is connected to one end of the strip and is driven by a timing mechanism at a predetermined rate, causing the strip to travel continuously in a lengthwise direction along a predetermined path. A sensing unit positioned along the path produces a trace on the strip which varies in amplitude in a direction generally transversely of the strip in response to the sensed condition. Release of the strip from the support member is prevented by a releasable detent. A disabling member connected with the detent moves the sensing unit out of contact with the strip whenever the detent is disengaged from the strip for release.