Abstract: A tube bird feeder comprising a seed tube having a side wall and at least one feed opening in the side wall, a top ring mounted on a top marginal edge of the seed tube, a cover removably engaged with the top ring, at least one perch mounted on the seed tube proximate the feed opening, and a base member removably secured to the seed tube adjacent the bottom marginal edge, the base portion having a protrusion engaging with an aperture in the seed tube proximate the bottom marginal edge.

Abstract: A bird feeder comprising a feed container having a side wall and a plurality of feed openings therein, a shroud extending about the feed container, the shroud having feed openings therein, the feed openings being spaced from the top of the shroud by a distance equal to between 20% and 80% of the total height thereof, a cover, a base, a center tube and a center rod within the center tube, the center rod being secured to the base and the shroud resting on the base, a spring mounted about the center rod, the arrangement being such that the feed openings in the shroud and the feed openings in the side wall are either aligned or misaligned depending on the weight on the shroud.

Abstract: A seed port for a bird feeder, the seed port being insertable into an aperture formed in the wall of the bird feeder, the seed port having at least one protrusion formed on a rear face of a front wall, the protrusion extending into a notch formed in a wall defining the aperture in the side wall. The seed port is not removeable after insertion.

Abstract: A tube bird feeder comprising a seed tube having an open top and an open bottom, a cover fitting on top of the seed tube to cover the open top, a base portion which is removably secured to the side wall, and a removable seed port structure mounted in a seed access opening.

Abstract: A squirrel resistant bird feeder which comprises a seed container, a seed tray mounted below the seed container, a shroud enclosing the seed container and seed tray with at least one feed opening in a lower portion of the shroud, a cover member extending over the shroud, a central tube extending between the seed tray and an upper portion of the seed container, a center post within the center tube, and a plunger comprising an upper plunger portion and a lower plunger portion, the upper plunger portion and lower portion being screwthreadedly engaged such that the length may be varied, a spring member mounted about the center post and biasing the seed tray and the lower plunger portion.

Abstract: A squirrel resistant bird feeder which comprises a seed container, a seed tray mounted below the seed container, a shroud enclosing the seed container and seed tray with at least one feed opening in a lower portion of the shroud, a cover member extending over the shroud, a central tube extending between the seed tray and an upper portion of the seed container, a center post within the center tube, and a plunger comprising an upper plunger portion and a lower plunger portion, the upper plunger portion and lower portion being screwthreadedly engaged such that the length may be varied, a spring member mounted about the center post and biasing the seed tray and the lower plunger portion.

Abstract: A tube bird feeder comprising a seed tube having an open top and an open bottom, a cover fitting on top of the seed tube to cover the open top, a base portion which is removably secured to the side wall, and a removable seed port structure mounted in a seed access opening.

Abstract: A squirrel proof bird feeder wherein there is provided a lower movable shroud which extends about a lower portion of the feed container having feed access openings therein, a spring member biasing the shroud to a position wherein feed container access openings and shroud access openings are substantially aligned while permitting the shroud access opening to move out of alignment with the feed container access opening when a predetermined weight is placed on the shroud. An adjustment is provided for adjusting the weight required to move the shroud.

Abstract: A squirrel proof bird feeder wherein there is provided a lower movable shroud which extends about a lower portion of the feed container having feed access openings therein, a spring member biasing the shroud to a position wherein feed container access openings and shroud access openings are substantially aligned while permitting the shroud access opening to move out of alignment with the feed container access opening when a predetermined weight is placed on the shroud. An adjustment is provided for adjusting the weight required to move the shroud.

Abstract: A bird feeder having a base and an outer wall extending upwardly therefrom with an access opening is said wall, a shroud extending about the feed container, the shroud also having a shroud access opening which is normally substantially in alignment with the feed container access opening to thereby permit access to the feed container by birds, a hanger connected to the feed container, an extendable means within the feed container interconnecting the shroud and feed container such that when a pre-determined weight is placed on the shroud, the extendable means will extend and cause the shroud access opening to move out of alignment with the feed container access opening to thereby deny access to the feed container. The extension on the extendable means is preferably tension adjustable such that an undesired species or marauder can be excluded from gaining access to the feed container.

Abstract: A device for use in a generally round or oval swimming pool or like body of water wherein a generally circular flow of water proximate the periphery of the pool occurs, the device comprising a preferably floatable skimming device having a water inlet and a water outlet with filter means between the inlet and outlet such that the flow of water tends to pass through the filter means, and means for securing the device to a fixed point to allow the water inlet to be situated such that the circular flow of water enters the inlet.

Abstract: A method of making a variable capacitor microphone in which the fixed capacitor element is formed by first coating the metallized surface of a relatively rigid insulating substrate with a polarizable dielectric material and then placing the substrate on one of a pair of spaced electrodes positioned in an ionizable gas and subjecting the gas to the action of alpha rays to produce ions in the space between the electrodes while applying a potential across the electrodes to cause ions to migrate toward the dielectric material to polarize the same to form an electret. After the fixed capacitor element has thus been formed, it is mounted in spaced relationship to a flexible diaphragm to form a microphone.

Abstract: An electret microphone assembly in which an insulating support disposed between the apertured front and back walls of a conductive housing has an enclosed portion contained in the housing and an exposed portion extending out of the housing through an opening formed in the side wall thereof. The support carries the back electrode of an electret microphone on the front of the enclosed portion and an FET amplifier circuit on the back of the same portion. Respective electrical contacts formed on the back of the exposed portion of the support extend inwardly through the side opening in the housing to provide external connections to the source and drain of the FET and to the amplifier common line.

Abstract: A hand-held microphone assembly for use with two-way communications equipment in which an electret-capacitor microphone is mounted in the upper surface of the barrel portion of a pistol-shaped casing. A push-to-talk trigger disposed at the end of the barrel actuates a double-pole, double-throw slide switch to couple the output of a local preamplifier in the casing to an audio output line leading from the casing and to make suitable couplings between three changeover lines. A resilient conductive strip disposed within the casing at the inner end of the slider element is actuated in response to the operation of the double-pole switch to couple the preamplifier to a normally disconnected amplifier power supply in the casing.