Precision slit of adjustable width for a spectral instrument

A precision slit of adjustable width for spectral instruments in which adjustably spaced slit jaws are guided for a first direction of displacement by a linkage system developed as a parallelogram, characterized by the fact that each slit jaw is carried by an arm which is pivotally connected with at least two guide parallelograms arranged on opposite lateral sides of the arm, said guide parallelograms being defined by a pantograph assembly of first and second intersecting sets of at least four equally spaced elongate parallel members, there being a pivotal interconnection of members of said sets at each intersection, whereby a diagonal alignment exists for at least four of said pivotal connections and diagonally through at least three of said parallelograms, said slit jaws confronting each other within the central one of said three parallelograms and their respective arms each having pivotal connection at the respective two spaced member intersections at one of the remaining parallelograms on said alignment, each of said arms having a longitudinal slot at its pivotal connection at one of its said two member intersections, first and second elongate guide members establishing guide alignments that are parallel to each other and to said arms and at opposite lateral offsets from said arms, first individual slides having engagement to said first guide member and connected to each of two pivotally connected intersections on an alignment parallel to said arms and at one lateral offset from said arms, second individual slides having sliding engagement to said second guide member and connected to each of two pivotally connected intersections on an alignment parallel to said arms and at the opposite lateral offset from said arms, and slit-width adjustment means including means for displacing at least one of said guide members in the direction perpendicular to said diagonal alignment and with respect to the other of said guide members.

An adjustable-width precision slit for a spectral instrument wherein each of two jaws has (i) a slit-defining edge and (ii) an associated elongate mounting arm which extends perpendicular to and away from its associated slit-defining edge, and means mounting said jaws via said arms with the respective slit-defining edges in adjustably spaced parallel confronting relation;

• said mounting means comprising a first two like parallelogram linkages wherein one of said arms is connected to form one link in common to both said first parallelogram linkages, with the parallelograms of said first linkages extending in opposite directions laterally of said one arm, a second two like parallelogram linkages wherein the other of said arms is connected to form one link in common to both said second parallel linkages, with the parallelograms of said second linkages extending in opposite directions laterally of said other arm;
• a first rigid tie member at lateral offset from and parallel to said arms and connected to form one link in common with one of the parallelograms of each of said first and second parallelogram linkages, a second rigid tie member at opposite lateral offset from and parallel to said arms and connected to form one link in common with the other of the parallelograms of each of said first and second parallelogram linkages;
• and adjustable means reacting between said rigid tie members and in the direction perpendicular to said arms for adjusting the spacing between tie members and thereby also effecting an adjustment in the spacing between slit-defining edges of said jaws.