Abstract: A FIFO shift register (100) includes a parallel data in-port (PIN) to each of its cells (101-132) and a means for managing input to determine for each cell whether it is to receive data and, if so, whether through its conventional serial in-port (SIN) or through its parallel in-port. The input manager comprises a bidirectional shift register of input manager cells arranged in one-to-one correspondence with data cells. A one-bit validity indicator stored within a given input manager cell is logically combined with asserted PUSH and PULL signals to determine the source of data for the associated data cell and its immediate successor. This arrangement not only provides greater speed by minimizing bubble-through time, but permits the FIFO shift register to be clocked. This capacity for synchronous operation permits ready VLSI implementation with concomitant advantages in economy, reliability and speed.

Abstract: A device which may be incorporated in a conventional magnetic tape transport prevents adhesion between the magnetic tape and elements of the tape transport such as the magnetic head and the tape cleaner. When the tape speed falls below a preselected minimum, the device mechanically displaces the magnetic tape without significant wear on the tape.

Abstract: A planar mounting board for needlework designs includes a multiplicity of evenly spaced perforations or holes along the periphery thereof to facilitate the precise mounting thereto of a canvas or fabric containing a completed needlework design by stitching the canvas or fabric to the mounting board through the perforations therein.

Abstract: An electronic calculator includes keyboard control means for enabling the user to either immediately execute a line of one or more alphanumeric statements entered into the calculator or store that entered line of one or more alphanumeric statements in the calculator memory.

Abstract: A bumper step for enabling the user to conveniently access the engine compartment of a truck is formed from steel plate material, for example, to include a lip for removably hooking the bumper step over a conventional truck bumper at any location therealong and a step member on which the user may conveniently stand. In one embodiment of the invention, an adjustable strap is provided between two components of the invention to facilitate adjustment of the height above ground of the bumper step.

Abstract: A sound system for use in government council chambers, corporate board rooms, and the like employs low level switching of the audio signal to selectively attenuate the audio output of a given speaker or group of speakers as a function of the source of that audio signal.

Abstract: An amplifier having a low DC drift characteristic incorporates a DC drift compensator which periodically samples the DC input offset voltage of the amplifier, holds the sampled value, then corrects the amplifier's input signal by the amount of the sampled value.

Abstract: An electronic calculator includes modular read-write and read-only memory units, a central processing unit, an output display unit, an output printer unit, a keyboard input unit, and input/output interface circuitry for facilitating the connection of one or more peripheral input/output units, such as an X-Y plotter, for example, to the calculator. When the calculator is coupled to an X-Y plotter, the user may employ commands entered from the keyboard input unit to move the plotter pen to an arbitrary position on the plotter platen whose X and Y coordinates are unknown to him and to subsequently cause the calculator to determine and display the X and Y coordinates of that arbitrary pen position.

Abstract: A portable roof edge seaming apparatus for aiding in the chemical welding of the edge of a sheet of vinyl roofing membrane to either an overlapped sheet thereof or to a vinyl clad metal edge member includes a fleece or cloth lined skid plate, a solvent reservoir, a brush member mounted forward of the skid plate for applying solvent from the reservoir to an area between the members to be welded, and a weighted roller mounted rearward of the skid plate for applying uniform pressure over the members to which solvent has been applied.

Abstract: A programmable calculator utilizes an initialization key for setting all program variables, including array variables that are stored as part of a program in the calculator memory, to a predetermined initial value.

Abstract: Apparatus for quickly and precisely installing depth rings on drills and for removing previously installed depth rings includes a base member on which are mounted one or more installation and removal mechanisms, each of the installation and removal mechanisms comprising a lever actuated push rod for moving a drill with respect to a retained depth ring, each of the installation mechanisms additionally comprising a dial indicator for accurately indicating the position of the depth ring with respect to the point of the drill on which it is being installed.

Abstract: A programmable calculator having modular read-write and read-only memory units, a central processing unit, a keyboard input unit, and an output display unit includes keys on the keyboard input unit for enabling the user to efficiently and effectively edit programs stored in the read-write memory unit.

Abstract: A highly accurate electronic temperature sensor/controller system employs one or more sensing devices, a precision voltage reference, a pair of analog multiplexers, a voltage-to-frequency converter, a microcomputer, a keyboard, an output display, and one or more solid state switches.

Abstract: An electronic calculator is provided by employing read-write and read-only memory units, a central processing unit, and an input-output control unit capable of bidirectionally transferring information between the memory or central processing units and a number of input and output units. The input and output units include a keyboard input unit and an alphanumeric display unit. The keyboard input unit includes means for entering a data entry statement into the read-write memory as part of a program of statements stored therein. The central processing unit includes logic means responsive to a data entry statement encountered during processing of a program stored in the read-write memory for controlling the alphanumeric display unit to indicate the nature of the data to be entered and thereby prompt the user as to the need for and nature of a data entry at the time such data entry is required during processing of that program.

Abstract: A programmable calculator employs modular read-write and read-only memories separately expandable to provide additional program and data storage functions within the calculator oriented toward the environment of the user and two sixteen bit LSI NMOS central processing units. One of the central processing units (LPU) is employed to perform language syntaxing, arithmetic, and general supervision of program execution. The second central processing unit (PPU) is employed for managing input/output operations. Communication between the two central processing units is accomplished by an arrangement through which the two central processing units share a common portion of memory. The calculator also includes a keyboard having a full complement of alphanumeric keys for entering programs and data into the calculator and for otherwise allowing the user to control operation of the calculator.

Abstract: A programmable calculator having modular read-write and read-only memory units, a central processing unit, a keyboard input unit, and an output display unit, includes keys on the keyboard input unit for performing angular measurement unit conversion.

Abstract: A hydraulically controlled mechanism employed to automatically raise and lower the sideboard of a truck box includes provision for positively locking the sideboard when it is in the fully closed position such that inadvertent opening of the sideboard is prevented even in the event of the loss of hydraulic pressure.

Abstract: An adaptable programmable calculator employs modular read-write and read-only memories separately expandable to provide additional program and data storage functions within the calculator oriented toward the environment of the user, and an LSI NMOS central processing unit, which includes the capability of bidirectionally transferring information between itself and various input/output units. The input/output units include a keyboard input unit having a full complement of alphanumeric keys, a magnetic tape cassette reading and recording unit capable of bidirectionally transferring programs and data between the calculator and a magnetic tape, a 32-character solid state output display unit capable of displaying every alphabetic and numeric character.