| 摘要 |
An image focusing apparatus for microfiche film readers and other optical systems has a lens holding apparatus which rests on a transparent or glass plate, a rotatable lens adjusting assembly in the lens holding apparatus, a shaft slidably and pivotally connected to the lens adjusting assembly, a knob on the shaft, and a shaft holder which fixes the position of the shaft with respect to the reader. The lens holding apparatus is universally mounted to the frame of the reader to enable the lens holding apparatus to move freely in response to changes in the angular disposition of the glass plate with respect to the horizontal plane. The lens adjusting assembly has an eccentric finger which translates the rotating motion of the knob and shaft into a vertical force, which moves the lens. The lens adjusting assembly has a barrel, a socket in the barrel and key slots along the socket. The shaft has a partially-spherical end and keys which slidably and pivotally fit into the socket and key slots. The simultaneous slidable and pivotal operative connection of the shaft to the lens adjusting assembly enables the operator to adjust the lens regardless of the angular disposition of the lens adjusting assembly with respect to the shaft. The connection also enables the lens holding apparatus to move freely in response to changes in the attitude of the glass plate with respect to the lens.
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