Engineering Dynamics Ltd.

John W Leask

John C Leask

Harry W Straus

An electromechanical and more particularly an electromagnetic brake is utilized in the control of exercise equipment including escalator type stair-climbing apparatus, in which electronically controllable torque, including a clamping torque, is applied to a rotary shaft to load the exercise equipment, thereby giving complete electronic control to the operation of the exercise apparatus including a safety locking function.

Braking system for exercise apparatus

A collimator suitable for use in the creation of more than one miniaturized image of a radioactive concentration simultaneously by a radiation receiving and imaging device, said collimator having at least two adjacent collimating sections separated by areas substantially opaque to radiation from the radioactive object, each such collimating section being a grid-like arrangement of wall portions, adapted to absorb substantially all radiation from the radioactive object which impinges thereon, extending between the top surface and the bottom surface of the collimator defining a plurality of holes therebetween of substantially any desired cross-sectional shape. The wall portions and associated holes of each collimating section are so disposed relative to each other that radiation from the radioactive object passing through the holes from the bottom to the top of the collimator will converge upon a point on a line passing through the center of the top surface of the collimating section located at an acute angle to a line normal to the center of the top surface of that collimating section. Two limitations must be adhered to. First, care must be taken in selecting the angle at which each collimating section converges to avoid interference between or among the image creating radiation rays emerging from the various collimating sections, and second each collimating section must contain sufficient wall portions to provide adequate selection of image creating radiation from the continuum of radiation radiated by the object and impinging upon the bottom surface of each section to allow the creation of a useable image.

Bi-focal collimator

A collimator for radiation receiving and imaging devices and a method for making such collimators including the steps of forming a plurality of modular elements each comprising a foil sheet bent so as to form a plurality of elongated ridges on both sides thereof so as to form elongated channels therebetween, partially inserting the ridges of one module into the channels on the adjacent side of the succeeding module in a modified mortis-tenon relationship successively and affixing them in that position, placing the assembled grid into a frame, and filling the spaces between the grid and the frame with radiation-opaque material, thereby forming an integral functional collimating unit.

Methods of collimator fabrication

A collimator for radiation receiving and imaging devices and a method for making such collimators including the steps of casting a plurality of modular elements each having a base from one side of which extends a first plurality of spaced columns and from the opposite side of which extends a second plurality of columns of shorter height than the first directly opposite the spaces between the first plurality of columns, inserting the first plurality of columns of one module into the spaces between the second pluraity of columns of the succeeding module in a modified mortis-tenon relationship successively and affixing them in that position, placing the assembled grid into a frame, and filling the spaces between the grid and the frame with radiation-opaque material, thereby forming an integral functional collimating unit.

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Carlisle, MA, United States of America

John W Leask