Patent GB-884399-A (GB)
Title: Adjustable microscope stage
Inventor: MELFORD DAVID AUSTIN
IPC: G02B21/32
Filed: 1959-04-22
Abstract: 884,399. Cam mechanism. T.I. (GROUP SERVICES) SERVICES) April 22, 1960 [April 22, 1959], No. 13659/59. Class 80 (3). [Also in Groups XX and XL (a)] An adjustable microscope stage includes a specimen carrier which is rotatable about an axis, and means for moving the specimen carrier in at least one direction at right angles to the axis of rotation, said latter means comprising a peg engaging in a scroll of a member which is rotatable about the axis of rotation, the rotation of the specimen carrier being achieved by turning the latter together with the peg and scroll linkage without relative movement between the peg and scroll. The stage is preferably associated with an optical microscope and an electron microscope or electron probe microanalyser, the stage including a table which is rotatable to bring the specimen carrier into register with either microscope. As shown, the stage comprises a table 3 supporting a number of specimen carriers 4, the table being mounted on a shaft 51 having a crown wheel 50 which is engaged by a pinion on a shaft 47 rotatable by an external knob 48. Indexing positions corresponding to the number of specimen carriers are defined by a spring- loaded plunger 54, which is axially slidable within the shaft 47 and engageable in a number of circumferentially spaced recesses 53 in a ring 52 secured to the underside of the crown wheel 50. Rotation of the table 3 brings a required specimen under an optical or electron microscope. One of the specimen carriers 5 is geared on a plate 6 having limited sliding movement in any direction with respect to a disc 7 mounted on a cylindrical sleeve 8. This sleeve 8 is rotatably mounted in the table 3 and can be turned by operating an external knob 41 to rotate a shaft which is geared at 44 to a shaft 45 provided with a gear 46 at its upper end, this gear 46 engaging another gear 24 attached to the lower end of the sleeve 8. Movement of the specimen carrier 5 in a plane at right angles to the axis of rotation of the sleeve 8 is controlled by a two-arm lever 9 which has a ball 10 engaging the under side of the carrier 5 and a ball at its other end engaging in a cubicle block 11. The lever 9 is universally pivoted by a ball 12; and a vacuum-tight seal is provided between the ball 12 and the recess in which it tilts and between the upper end of the sleeve 8 and the table 3 in which it rotates. One face of the block 11 is engaged by a spring- loaded plunger 13, the opposite face being engaged by a plunger 16 slidable in the sleeve 17 and having a pair of pegs 18 engaging in successive turns of a spiral scroll 20 in a gear 21. This gear 21 is rotatable about the sleeve 8 by a gear 31 mounted on a shaft 30 provided with a crown wheel 28 which is engaged by bevel pinion 27 on a shaft 26 that is rotatable by an external knob 25. Within the shaft 26 is another shaft 33 operable by a knob 32 and having a pinion 34 engaging a crown wheel 35 on a shaft 36, which is geared at 37 to a gear 23 also having a spiral scroll engaged by pegs on a plunger disposed at right angles to the plunger 16. In this way by rotating the knob 25, the specimen carrier can be moved in one direction and by rotating the knob 32 the specimen carrier can be moved in an orthogonal direction. Further, by pulling out the two knobs 25 and 32, the pinions 27, 34 are disengaged from their crown wheels so that the shafts 30 and 36 are free from restraint and, when the knob 41 is operated to rotate the shaft 45 and thus the specimen carrier 5, the shaft 45 carries the two shafts 30, 36 with it. The orthogonal settings are thus left undisturbed during rotation of the specimen carrier. Similarly, when table 3 is rotated the shaft 51 carries with it the shafts 30, 36 and 45 so that the orthogonal settings and angular position of the carrier relative to the table 3 are unchanged.