Abstract: A dental chair has its backrest connected to the seat by a scissor linkage arrangement which effects the moving together of the contiguous portions of the backrest and seat concurrently with movement of the backrest from an upright to a reclined position.

Abstract: The circular crystal of a temperature indicating instrument has a circular flange rotatable in a channel in the instruments' casing. Fingers on the casing have teeth which mesh with teeth on the flange. The fingers yieldably hold the crystal in place but the crystal can be forcibly rotated.The crystal has a slotted post thereon and on said post is a bimetallic spiral coil the inner end of which is in the post's slot. Another post in the casing covers the slot to keep the coil in place on the former post.On the back of the casing is a supporting bracket adjustable to several positions.

Abstract: A nonpermselective porous membrane sheet, which comprises a natural or synthetic fiber material substrate having coated thereon a mixture of a plastic binder material and a non-ion exchangeable filler material, said membrane being capable of transmitting negatively and positively charged ions between the electrodes in an electrodeposition painting operation and at the same time capable of preventing backflow of the electrolytes between the electrode chambers.

Abstract: Energy saving heating vessel adapted for heating by contact with bottom surface heating means, such as a hotplate, is disclosed. The described vessels typically have a heating rate 2 to 5 times faster than a conventional glass vessel while consuming about half the energy or less. The vessel includes sidewalls of a non-metal material such as a plastic, and a composite bottom. The composite bottom has a high heating surface contact area and includes a liquid-impervious innermost film of a non-metal material of a minimal thickness to minimize its resistance to heat transfer through it, bonded to and supported by an outermost layer of a rigid good thermal conductivity material preferably a graphitic material having a conductivity at least ten times higher than the sidewalls and the inner film, such outermost layer being the hot plate contacting element. The vessel can be made in a variety of shapes adapted for use in laboratory, domestic, service and industrial applications.

Abstract: A dental unit has dental instruments carried by individual nests, the nests being selectively movable from a storage position to a readiness position. Each nest is carried to the readiness position in a controlled manner such that the axis of the instrument becomes horizontal and moves downwardly as the instrument approaches the readiness position.

Abstract: An ion treatment electrode has a porous polymer substrate with a conductive coating. A non-conductive solution impervious border is provided by applying to adjacent substrate, sufficient heat and pressure to melt the polymer and disrupt the conductive coating.

Abstract: An orthodontic bracket assembly is adapted for use with an arch wire in straightening a tooth having a crown long axis preferrably disposed at a particular angle with respect to an occlusal plane. The bracket assembly includes a base for fixing the assembly to the tooth and at least one tie wing having a fixed relationship with the base. The tie wing has a facial surface defined by a mesial edge, a distal edge, a gingival edge and an occlusal edge. At least one of the gingival edge and the occlusal edge are disposed at the particular angle with respect to at least one of the mesial edge and the distal edge of the tie wing, so that the facial surface of the tie wing has a generally rhomboidal configuration. This facilitates alignment of the assembly with respect to the occlusal plane and the crown long axis of the tooth.

Abstract: An indicator device which comprises a backing member, an indicator chemical, such as sebacic acid, which has the capability of wicking through a wick material, wicking means having one end of said wicking means in physical contact with said indicator chemical, said indicator chemical and wicking means being contained within a polypropylene envelope with the top and bottom interfaces of said envelope being sealed together to mechanically bond the wicking means and indicator chemical at the film envelope interfaces.

Abstract: A circuit protects a high voltage supply for x-ray tubes from the damaging effects of a tube flashover or the like. The circuit monitors line current, and high voltage and reacts to an increase in line current occurring with a corresponding drop in high voltage to turn off the high voltage.

Abstract: Test tube rack for holding a plurality of test tubes in an upright position and further adapted for holding the test tubes at slant angles of 5.degree. from horizontal and 20.degree. from horizontal for the preparation and growth of agar slant tube cultures or liquid tube cultures. The racks are further adapted for positive interlock stacking.

Abstract: A nonpermselective porous membrane sheet, which comprises a natural or synthetic fiber material substrate having coated thereon a mixture of a plastic binder material and a non-ion exchangeable filler material, said membrane being capable of transmitting negatively and positively charged ions between the electrodes in an electrodeposition painting operation and at the same time capable of preventing backflow of the electrolytes between the electrode chambers.

Abstract: Disclosed is a pressure adapter and containment vessel for converting a vacuum filter unit to use as a pressure filter. The containment vessel includes an off center well in the bottom of the vessel for supporting the filter unit, the off center well also providing a variable spacing between the wall of the containent vessel and the outlet spout of the filter unit. In addition, the containment vessel has a screw closure which cooperates with the cap of the filter unit to insure the filter unit is not pressurized until after the screw closure is properly attached to the containment vessel.