Abstract: A pick for a stringed instrument having a finger gripping portion and a picking portion where the thumb side gripping is formed with a generally rectangular recess and the forefinger gripping side is a generally rectangular slot having a nominal center line forming a substantial transverse angle with the length of the thumb gripping portion.

Abstract: A boom for spraying equipment comprises at least one elongate member having an outer skin over a core of a material having a lower density than the skin. The core material may occupy all of the space within the outer skin or the elongate member may be hollow, at least part of a side wall of the member being formed of an outer skin, an inner skin and core material sandwiched between the inner and outer skins. The outer skin and the core material may be metallic or non-metallic, suitably a fibre reinforced plastics material. There may be a plurality of elongate members which are mutually spaced, parallel arranged and extend in a direction lengthwise of the boom.

Abstract: A projection lens for a cathode ray tube display which comprises from the image end a first lens unit of relatively weak optical power serving primarily to correct aperture dependent aberrations, a second lens unit of strong positive power permitting decreased equivalent focal length and resulting wide field angle, and a third lens unit having a strongly concave image side surface and serving to correct the Petzval curvature of the surfaces of the other lens units. The second lens unit comprises two elements of overall biconvex shape separated by an air gap. The facing surfaces of the two elements of the second lens unit are of relatively weak optical power and at least one of the surfaces of the two elements of the second lens unit is aspheric to contribute to the corrections provided by said second lens unit.

Abstract: A projection lens for a cathode ray tube display which comprises from the image end, a first group of relatively weak optical power serving primarily to correct aperture dependent aberrations, a second group of strong positive power, and a third negative group having a strongly concave image side surface and which serves as a field flattener and to correct the Petzval curvature of the services of the elements of the other groups. The second group comprises two elements which provide substantially all of the positive power of the lens and which define an air meniscus therebetween with the minor dimension at the optical axis. The optical powers of the second group bear a predetermined ratio and have a minor dimension at the optical axis.

Abstract: A compact projection lens for a cathode ray tube having a field angle as great as 73.degree. which may utilize only three lens elements where the first lens element from the image side has two aspheric surfaces in the shape of an overall meniscus which goes from positive optical power at the optical axis to relatively strong negative optical power at the limit of the clear aperture of the lens. The spacing between the first and second lens elements is chosen to aid in contributing to correction of field curvature.

Abstract: A projection lens system adapted to project an image from a cathode ray tube and consisting from the image end of a first lens unit of weak optical power, a second lens unit of strong optical power including a biconvex glass element, a third lens unit of strongly negative optical power having a convex image side surface and serving as a field flattener, the first lens unit consisting of a first meniscus shaped element having positive power at the optical axis having at least one aspheric surface and being convex to the image, and a second meniscus shaped element having at least one aspheric surface, the said second meniscus being convex to the second lens group and closely spaced thereto. The second meniscus may be on either side of the second lens unit and is of very weak optical power.

Abstract: A zoom lens having a range of equivalent focal lengths extending from a range below the dimension of the diagonal of the image frame to a dimension substantially above and having a zooming range of up to six to one or greater where the lens has a plus, minus, plus, plus lens unit configuration with a strongly negative second lens unit and a fourth lens unit designed to have a given power and telephoto ratio to compensate for a remote aperture stop located in the third lens unit.

Abstract: A zoom lens having a range of equivalent focal lengths from a dimension below the diagonal of the image frame to above with a zoom ratio of substantially three to one or greater having a second negative lens unit of relatively strong optical power where the second lens unit comprises a negative component, a positive meniscus concave to the object and a doublet including a positive element convex to the object and the optical power of the positive element of said doublet is substantially greater than the optical power of said positive meniscus.

Abstract: An internal focusing lens comprising from the object end a first positive group, a second positive group and a third negative group, the second group being axially movable to focus the lens.

Abstract: A teaching system utilizing magnetic tape which is prepared in sectors with a message segment and position indicators in the form of transparent windows which are photoelectrically detected. After a message or question is played, a first window is detected by a first detector and the tape drive motor is de-engergized with another window positioned before one of a plurality of other detectors. The operator then attempts to answer or identify the message by making a selection corresponding to one of the plurality of detectors, and if a correct answer is given, a signal is given to the operator.

Abstract: A concentrating reflector adapted to focus light on a target spaced a predetermined distance from the reflector comprising a lens, a linear echelon element closely positioned to said lens and a mirror surface, the lens, the echelon element and the mirror surface being so arranged that light entering the lens and the echelon element is refracted and reflected back through the lens to said target for a given angle of incidence of light rays thereon.

Abstract: Method and apparatus for determining the frequency of movement of an object or inspection of a moving object where a liquid crystal viewer is pulsed at a rate equal to the rate of movement of the object. Method and means are provided for obtaining a variable viewing window for each period of the pulsing means.

Abstract: A container and dispenser for granular or powdered material in which the container has an upper aperture and dispensing orifices are defined by a flexible member which permits the orifices to be expanded with resulting contraction to break loose clogged material from the orifices. The flexible member is in the form of a conical spring having spaced notches along the length thereof to channel the condiment through the grooves and provide a more uniform dispensing pattern of the condiment.

Abstract: An electrolytic metal recovery process and apparatus for removing metal from a low metal content solution utilizing a recovery cell where a bed of metal is disposed on a perforate member above the floor of the cell and the cathodes of the cell extend into the bed to provide an essentially infinite area cathode through which the solution treated filters prior to removal from the cell.

Abstract: A video camera system adapted for low light levels and daylight where a prism is selectively movable to present an image to one of two optical paths for either mode of operation. In the low light level mode of operation, a relay lens is provided to relay the output of a light intensifier to the target of a vidicon.

Abstract: A domestic hot water heating system which disables the normal aquastat during set-back periods where the temperature of the water source is sensed at the output manifold and the temperature of the water also is sensed a predetermined distance along the manifold to determine a demand or lack of demand for hot water. The system will enable the aquastat during a set-back period when demand is made and disable the aquastat when there is no longer a demand.

Abstract: A rehydrator which dispenses precise amounts of liquid to each row of wells in a titration tray where the dispensing of the liquid is performed through valving means in timed relation to indexing of the platform to present a row of wells beneath the dispensing orifices. The indexing of the tray and the valving means are accomplished by the same drive means to obtain the timed relation.