Abstract: Air that becomes entrapped in a closed mold cavity during the injection of liquid plastic material into the cavity is vented into the flowing liquid coolant of the mold to be exhausted therewith while leakage of coolant into the mold cavity during nonventing is prevented by maintaining the coolant at less than atmospheric pressure.

Abstract: A system for individually adjusting a plurality of remotely located servo units according to the position of a manual control for each servo unit by broadcasting a carrier wave that is switched on and off for division into repeating sequences with the reset signal to repeat a sequence having a short broadcast duration followed by a long silent period and in which the shifting of the control from one servo unit to the next in a sequence is directed by the leading edge of a broadcast period that occurs in a sequence for each servo unit and which is of the same duration as the reset broadcast signal to thereby decrease the total broadcast time for each sequence while also reducing the possibility of interference by extraneous signals.

Abstract: A system for directing sequential commands to a plurality of device control circuits, each of which is capable of being individually addressed and controlled to perform one of a plurality of modes of energization by the input commands. The control circuits are used to control energization of devices, such as peripheral devices of numerical control machines and may utilize feedback status signals from the devices, in some modes, to regulate the receiving of further input commands. The commands may be each acted upon sequentially or some may be grouped to be acted upon simultaneously.

Abstract: The tendency of a stepping motor to oscillate or flutter under some mid-velocity conditions is minimized by reducing the deviation of the motor's rotor from its normal synchronous position by altering the time about a nominal time when a change of energization of the motor's windings is to occur after receipt of an input pulse in accordance with the duration of the decay current that existed at the prior change of energization.

Abstract: Linear velocity changes between steps are obtained by a digital circuit in a stepping motor system that receives commands of the number of steps to be produced in successive time intervals by providing a string of pulses during each interval and selecting certain of said pulses to provide motor steps with the selection being initially determined by the number of commanded steps in the interval and further being determined by whether the number of commanded steps for the interval has the same number of steps, a greater number or a lesser number than in the immediately preceding interval.

Abstract: Tool offset compensation for a commanded path for a two axes NC system that produces movement by axis determination of sequential steps, is provided by having the tool offset the desired value, placing the tool center in the same quadrant as the direction of the commanded path and then making the tool center normal to the beginning of the commanded path. For a linear commanded path, the NC system then produces the commanded path while for an arcuate commanded path, the radius of the movement path produced is made to be the algebraic sum of the commanded path and tool center radii with additional incremental alterations without a corresponding movement being made in the numerical extent of the commanded path to utilize the same numerical extent for controlling the extent of the movement path.

Abstract: A stepping motor for providing movement in accordance with a repeating three step sequence with the third step being effected by a permanent magnet field and with the other two steps being effected by sequential sole energization of a pair of windings. The third step position constitutes the deenergized rest position of the motor.

Abstract: A system for accepting commands of the number of steps in a movement and for producing motion commands in a motion system that divides the movement into the number of steps in successive time intervals with the motion commands consisting of altering the number of steps between adjacent time intervals that are required to produce the movement.

Abstract: An electric motor having a stator and a rotor in which the stator is formed with an encapsulating hardened plastic shell formed with a through aperture in which the rotor is positioned and which has portions that accurately concentrically support the motor with respect to the stator.

Abstract: A swimming pool framework for defining an in ground opening for receiving a water containing liner in which the framework consists of a plurality of joined together arcuate and straight panels with the panels being rigid and formed of hardened polyester resin containing glass fibers.

Abstract: A threaded nut having a through radial slot bridged by a screw and a diametrically opposite partial radial slot that leaves a cross-sectional area of the nut which provides a tensile strength that is related to the ability of the screw to close the through slot whereby the nut, when clamped onto a shaft, is essentially evenly compressed about its contact area with the shaft.

Abstract: A circuit for supplying an error signal when the instantaneous difference between the number of command pulses and the number of steps produced by a stepping motor exceeds a value from which the motor cannot recover to overcome the difference.

Abstract: A motion control system in which motion is set by the number of whole steps to be produced in consecutive time intervals where the selection for each time interval is from a plurality of different numbers arranged in a sequential progressive order with a manual control causing the system to select numbers for consecutive time intervals from its last selected number sequentially through the order to one alternating repeating number for the lowest speed and a higher number for a maximum speed, in either direction. The system further enables the operator to adjust the rate of the steps in a time interval and the duration thereof, thereby altering motor speed without changing the number of steps in a time interval. When the operator releases control, the system automatically makes the motor assume its stopped, non-moving state.

Abstract: Two single pole flexible blade snap switches are mounted together to have both actuated essentially simultaneously by the same position of a common element by mechanically connecting together but electrically insulating the free ends of the two blades.

Abstract: A circuit for varying the rate of velocity changes of a digital motor wherein the motor produces movement that is commanded by successive lengths with each length having an extent defined by a whole number of steps and in which each length by its extent sets its own velocity whereby non-linear velocity changes in accordance with motor speed are obtained from a command that includes just length extent information.

Abstract: A variable diameter tooth cleaner formed by a plurality of elongate filaments to have a brush portion and a string portion with the string portion having two parts and with the brush portion being placed between the two parts. The string parts may be flexible or for spaces associated with fixed bridges may be formed with a rigid end extent for enabling insertion by pushing into the spaces.

Abstract: A device for providing a measurement of the value of the ratio of two pressures by sensing the position of a member that is urged in one direction by one pressure and oppositely by the other pressure with the element further having both pressures set against the same movable support of the element. A third pressure of essentially a high vacuum acts on the remainder of the element not acted on by the other pressures and minimizes the effects of temperature while enabling the device to be precise over a wide range of pressures.

Abstract: A motion control system and method that subdivides a movement into commands for sequential lengths that the system is to produce in sequential constant time intervals with each time interval having a length. Each length has an extent in steps along each axis and the difference in the number of steps between adjacent extents is limited to that which the motor's ability can accommodate. Each command directs the selection of a present extent with the quantity of a command being reduced by commanding only the difference between the present extent and the immediately prior extent. For essentially constant velocity contouring along two axes an endless sequential series of essentially constant length vectors is provided and each command for a present vector directs the selection based on the relation between it and the prior selected vector. Selection may be made from a number of series of vectors each having a different size.

Abstract: A motor control for a stepping motor having windings energizable in a predetermined sequence to produce an incremental movement for each command pulse has a programmed read only memory. The control can be set so that each input pulse can command either a half or a full step and the control can further be set to have half step high speeds energize the motor for full steps for every other command pulse to thereby increase the high speed half stepping torque.