Abstract:
A pair of electro-acoustic transducers, one functioning as a speaker and the other functioning as a microphone, are operatively coupled to a reference which in turn is in communication with a fluid. A regenerative frequency filtering loop is operatively coupled between the transducers and functions to apply amplified signal to the speaker and produce an acoustic signal which propagates through the medium. The acoustic signal is sensed by the microphone and coupled to the regenerative loop input. For certain frequencies, the spacing between the transducers together with the speed of propagation of sound through the fluid combine with the frequency filtering of the regenerative loop to cause the loop to regenerate at a frequency indicative of the relative speed between the reference and the fluid.
Abstract:
A ramp assembly provides loading of small off-the-road vehicles onto, and unloading of such vehicles from the bed of a pick-up truck. The assembly includes a flexible support such as a sheet of lightweight chain link, cloth belting or the like which is connected at the upper end to the corner posts of the truck bed or otherwise secured to the truck and which is tensioned at the other end thereof by an elongate support member, connected at one end to the ball hitch on the truck. The connection to the corner posts is made by notched members which extend laterally from both sides of the flexible support to engage the walls of the posts.
Abstract:
A relief valve for relieving excessive fluid pressures in a fluid pressure system comprising: a valve body having a cavity therein and an inlet port and an outlet port in fluid communication with the cavity; and a plug assembly carried in the valve body for reciprocal movement between a closed position in which the plug assembly prevents flow of fluids through the inlet port and an open position, in which the plug assembly permits flow of fluids through the inlet port and into the cavity for exit through the outlet port. A release mechanism is carried by the valve body for holding the plug assembly in the closed position but responsive to fluid pressures above a predetermined amount at the inlet port to release the plug assembly for movement toward the open position, the release mechanism including a split ring engageable with a corresponding annular shoulder carried by the valve body for holding the plug assembly in the closed position, the split ring being radially contractable in response to predetermined fluid pressures for disengagement from said annular shoulder, allowing the plug assembly to move toward the open position.
Abstract:
The present key telephone system comprises cordless telephone stations (FIGS. 6 and 7) which communicate over a line-of-sight transmission end link (276 or 277). The system further comprises a central controller (101) for switching communications between the cordless stations and to the message network. The central controller does not provide any station to transmission channel concentration. Concentration occurs in the bidding by a cordless station for access to a channel provided by the line-of-sight transmission end link. A particular number of transmission channels are provided by the line-of-sight end link which are bid for by any practical number of cordless stations. Subsystem controllers (104) are provided in a large cordless key telephone system. The subsystem controller reformats data for transmission between the central controller (101) and a cordless station. A unique code identifies a cordless station so that the allocation of a new channel to a cordless station may occur automatically when a cordless station is detected within the boundaries of a new subsystem.
Abstract:
A digital FSK transmitter utilizing a clock feedback signal driving an accumulator to operate a pair of registers having a pair of preset numbers stored therein to selectively add said numbers through a binary adder to the accumulator to output the FSK signal thereby.
Abstract:
A digital FSK receiver includes a zero-crossing detector which detects the zero crossings in an FSK signal having at least two signal frequencies. The time interval between zero crossings is then measured with a first interval value corresponding to one of the signal frequencies and a second interval value corresponding to the other signal frequency. An accumulator outputs a digital signal which depends on whether the interval is at the first value or the second value, the digital signal including logical zeros and ones.
Abstract:
A fast-acting reliable electrically operated normally opened or normally closed valve includes a piston which is spring-biased open and which is actuable by pressurized actuating fluid to drive a plug against a valve seat to terminate working fluid flow. Operating current is passed through stainless steel and copper tubes which are connected in series and contain actuating fluid. The stainless steel tube is heated by the current and vaporizes the actuating fluid-generating pressure which forces the cooler fluid from the copper tube into driving relation with the piston. When current is turned off, the stainless steel tube cools decreasing the vapor pressure. The cooler fluid from the copper tube is forced into the stainless tube by the biasing spring and accelerates condensation in the stainless steel tube to lower the pressure and quickly re-open the valve. A unique seal arrangement includes an elastomeric sleeve disposed about a portion of the piston and secured at its ends to the piston and piston housing, respectively. The piston housing wall is arranged to restrain bulging of the seal at any one location during the piston stroke, thereby preventing rupture of the seal.
Abstract:
A pressure indicating device according to the present invention includes a diaphragm assembly engaging one extremity of an indicator actuating means whereby flexing of the diaphragm caused by fluid pressure or other force will induce movement of the indicator actuating means. Movement of an indicator in relation to a fixed delineated face caused by movement of the indicator actuating mechanism results in a visual representation of reading bearing some predetermined relationship to the pressure causing the flexing of the diaphragm.