Abstract: A tap is strapped to the toe of ordinary street shoes for amateur type tap dancing and slipped over the fingers of those confined to wheelchairs for hand tapping. A thin body of hard material has spaced slots thru which a strap is passed which is fastened over the top of the toe of the shoe. The tap body is thinned on one surface between the slots and is thinned outboard of the slots on the other side to accomodate the thickness of the strap. The strap is preferably elastic and coated with a tacky material on the shoe side to retain it in place on the toe of the shoe.

Abstract: In a lithographic printing apparatus, the rollers that supply ink and/or water to form rollers have a surface with minutely intermixed hydrophilic and oleophilic areas. The amount of water retained by a roller is dependent upon the total of the hydrophilic areas, and the amount of oil-based ink retained by the roller is dependent upon the total of the oleophilic areas. A preselected ratio of oil to water is obtained by selecting the ratio of hydrophilic areas to oleophilic areas.

Abstract: A light intensity filter for a telescope or other optical instrument viewed by the human eye is formed of an opaque material having a plurality of holes or windows. These windows transmit a reduced amount of light to the image-forming optical component. The area of the windows relative to the area of the optical component is selected to the light intensity being imaged. The filter is especially useful for telescopes and the like, wherein the image is viewed by a human observer and the light source is momentarily of great intensity. Under these conditions the filter prevents temporary blindness of the observer due to excessive illumination, for example, tracking a moving object across the sun.

Abstract: A reflector or mirror for the visible and rear infrared spectrum is formed by multicoating copper with one-fifth wavelength and three-quarter wavelength films. These films are alternating low and high index films, and MgF.sub.2 and TiO.sub.2 are presently preferred. A thin bonding layer of TiO.sub.2 is used to secure adhesion of the MgF.sub.2 to the copper. This coating enhances the reflectance in the visible range without appreciable degradation of reflectance in the near infrared, so that the resultant curve of reflectance-versus-frequency is substantially flat. The resulting coating is hard and tough and may be cleaned without injury and withstands high humidity.

Abstract: A dental articulator has a generally horizontal base, one end of which acts as the lower bow. Projecting upwardly from this base is a stem. Mounted on the top of the stem by a slip-on construction is a removable hinge support. The hinge support has a pair of spaced vertical flanges, each of which has an elongated slot inclined to the horizontal at an angle approximating the angle between the jaws that the human condyles make upon forward and rearward motion. An upper bow is hinged to the flanges by a hinge pin passing through the elongated slots. Elastic bands engage both ends of the pin and the hinge support to normally keep the pin in the lower end of each slot. The bands are resilient enough to allow the operator to pull the upper bow backwardly along the condyle angle to check the teeth for forward and backward clearances and also to allow the operator to twist the upper bow with respect to the lower bow to check for clearances upon lateral movement of the teeth.

Abstract: A vertical bar is placed over an incision and is spaced from the incision by upper and lower spider legs that have feet resting on the patient's body. The upper spider feet are held to the body by a neck strap and the lower feet by a waist strap. The bar is formed of telescoping sections to accommodate body movements and to adjust to patients of different size. The upper spider legs are V-shaped in elevation to permit the user to wear an open-neck shirt without the protector being visible.

Abstract: Pigments are preserved on the surface of an artist's palette by storing the palette in a waterproof container having sufficient water to cover the pigments deposited on the surface of the palette. The container is made flat and small for portability.

Abstract: A single housing for insertion in one hole in a sink provides three fluid flows: (a) drinking water (b) dishwater effluent and (c) water treatment effluent. In addition, a vent or air gap to atmosphere is provided at the housing for the two effluents to satisfy code requirement of an air gap between the dishwater and drinking water device, and the sanitary sewer. A vented airspace is also provided between the drinking water pipe and the housing.

Abstract: A dart is made with a body that breaks away from the point upon impact and/or vanes or flights that break away from the body upon impact. The objective is to minimize the size of the embedded dart in a target so that subsequent darts can be thrown to the high score area of the prior darts. The breakaway is accomplished by relative movement upon impact between point and body and by the force of gravity breaking apart a magnetic hold between body and point. Springs are also used to separate the point and other parts and/or to hold the point in projected position during flight and to allow telescoping upon impact.

Abstract: A multilayer adhesive strip is adhered to the tread of an automobile or other vehicle tire transversely of the tread and generally axially of the wheel. Each layer has a different color, and wear on one part of the strip faster than another will expose a different color or colors that will indicate the wear pattern. Thin easily worn material may indicate the pattern in a mile or two of driving whereas thicker or tougher strips give results over a longer period of use. For example, differential wear in the center indicates over-inflation, differential wear at both ends indicates under-inflation, and differential wear at one end of the strip indicates wheel misalignment.

Abstract: A metal supporting pier for modular houses and mobil homes rests on a solid foundation having an upwardly projecting threaded bolt. The pier has a downwardly depending threaded rod that engages the bolt, preferably by use of a turnbuckle. This tie-down structure so tightly holds the piers to the foundation that there is no lateral shifting under seismic jolt, nor is there any vertical movement. The pier, accordingly, can be used to meet the most stringent building code requirements for housing supports.

Abstract: A pair of socks is held together from the time it is removed for laundering, during washing, and, later, by means of a flexible patch secured to each sock, the patches of a pair adhering to each other when pressed together. A manual pull will separate the socks for use. Flexible hook-and-pile patches are presently preferred inasmuch as their flexibility avoids stretching and tearing the socks during washing. The hook patches are prevented from catching on the trousers or other clothes of the wearer by closing an integral or attached patch of pile to cover these hook patches, and the patches are opened up for additional bonding area with matching hook-and-pile patches on the other sock.

Abstract: Video cameras and illuminating lights on the helmets of commercial divers are caused to give satisfactory images in turbid water by a combination of camera adjustment and very low light levels. Lights of five to twenty-five watts total are employed with video cameras that have the sensitivity increased five to ten times normal and wherein the useful light range of the camera is adjusted to be three to five times the illumination from the lamps. It is desirable also to render the automatic gain control of the camera inoperative, at least over the lower part of that light range of the camera.

Abstract: A housing of U-shaped cross section fits over the trigger guard of a gun to cover the trigger guard and prevent access to the trigger. A latch member is disposed in the housing and is biased by an elastic member, for example, a spring, to engage the trigger guard. An external member is accessible from the outside of the housing for manual pressing to overcome the spring and thereby depress the latch for removing the housing from the trigger guard. By selecting the strength of the spring the gun can be rendered safe against children who have not enough strength to overcome the spring. Adults, however, can quickly remove the housing by manual pressure and make the gun instantly available for use.