Abstract: A portable, thermally insulated container having an isothermal chamber for storing temperature sensitive material. An electronic circuit activates a heater when the temperature in the chamber is below a preselected magnitude and activates a Peltier heat pump to cool the chamber when the temperature in the chamber is above a preselected magnitude. The electronic circuit operates a fan for the intake of air into the chamber while the Peltier heat pump is operating and discontinues the operation of the fan while the heater is operating. Included in the electronic circuit are two sets of dual operational amplifiers. A temperature sensor responsive to the temperature in the chamber controls the operation of one set of dual operational amplifiers for operating the Peltier heat pump to cool the chamber and controls the operation of the other set of dual operational amplifiers to heat the chamber.

Abstract: A thermostat is disclosed having a bimetallic strip actuating a single pole, double throw switch, one throw to sense temperatures below the lower limit of a set point range and the other throw to sense temperatures above the upper limit of the set point range. In typical applications one throw for actuating heating and the other throw for actuating cooling. The bimetallic strip is provided with typically a cantilever support at one end and extends between dimensional spaced double throw contacts at the opposite end. Spacing of the contacts determines magnitude of the set point range. An intermediate beam type support is provided between the cantilever support and double throw contacts. This beam support consists of an adjustment screw acting on one side of the bimetallic strip and a spring directly opposing the adjustment screw.

Abstract: A web guide system wherein misalignment of take-up and supply rolls relative to a reference surface may be compensated without tape distortion by a crown pulley and an adjacent concave web guide. The concave web guide is a fixed, flangeless post about which the web is partially wrapped. The web tends to be self-centering in the concave curved portion of the guide. Tape is fed from a roll to the concave guide and then to the crown pulley of minimum radius which is mounted for axial as well as rotational motion. Pulley axial motion promotes equal edge tension and completes web self-alignment. Final axial alignment without edge pressure is accomplished by fixed tape edge-guides in the region of the head.

Abstract: A tape cartridge in which tape is driven from a tape-supply hub onto a tape take-up hub by an endless drive-belt loop engaging the tape-wound hub peripheries. Tape tension variation due to the differences in the radius to the drive-belt center line and the radius to the tape center line is reduced by introducing fixed friction posts in the tape path. One post is located so as to be in constant contact with the tape as it spools off of the supply roll. Another post is located so as to be in constant contact with the tape as it winds onto the take-up roll.

Abstract: A dual magnetic tape cartridge includes a first reel-to-reel tape wound between two coplaner hubs. A tape loop, extending between the hubs, is guided along a first path and across a tape head access opening. The second tape, in belt form, is guided along a second path and across the tape head access opening at a different level. A drive belt, frictionally engaging first tape peripheries on the hubs, is entrained over portions of a forward drive roller and over portions of two spaced rear idlers. The second tape is entrained over slightly smaller diameter portions of the drive roller and over other portions of the rear idlers to thereby also function as a tensioning belt for the drive belt, causing greater tension in drive belt portions engaging the first tape on the hub acting as the takeup hub than in other belt portions engaging tape on the other hub.

Abstract: A dual magnetic tape cartridge includes a first reel-to-reel tape wound between two coplaner hubs. A tape loop, extending between the hubs, is guided along a first path and across a tape head access opening. The second tape, in belt form, is guided along a second path and across the tape head access opening at a different level. A drive belt, frictionally engaging first tape peripheries on the hubs, is entrained over portions of a forward drive roller and over portions of two spaced rear idlers. The second tape is entrained over slightly smaller diameter portions of the drive roller and over other portions of the rear idlers to thereby also function as a tensioning belt for the drive belt, causing greater tension in drive belt portions engaging the first tape on the hub acting as the takeup hub than in other belt portions engaging tape on the other hub.