Nec Corporation

Eagle Industry Co., Ltd.

Eiji Okamoto

Katsuhiro Nakamura

Satoshi Shimizu

A spoolis provided with a second land sectionthat blocks a portion between the spooland the valve sleeveat a position between the output port Pand the lead-in port Pwhen the spoolis located in a position for connecting the channel for input Tand the channel for output Tvia the input port Pand the output port Pand blocking a channel leading from the channel for output Tto the channel for discharge T, and when the spoolis located in a position for connecting the channel for output Tand the channel for discharge Tvia the lead-in port Pand the discharge port Pand blocking a channel leading from the channel for input Tto the channel for output T

Spool valve

The present invention provides a solenoid valve able to control flow amount as desired without receiving influence of change in fluid pressure. In the present invention, in a control valve for opening and closing a first poppet valveand a second poppet valveby a solenoid portion, a first pressure receiving area Swhich is a seating area of the first poppet valve, a second pressure receiving area Swhich is a seating area of the second poppet valve, a third pressure receiving area Swhich is a pressure receiving area of a first pressure sensing portionand a fourth pressure receiving area Swhich is a pressure receiving area of a second pressure sensing portionare made approximately equal to each other. Thereby unbalanced forces received from fluid flowing in and out when each poppet valve is actuated are all canceled.

Solenoid valve

The present invention relates to a control valve capable of performing capacity control independent of the pressure of operation fluid. In the control valve which opens and closes a first poppet valve and a second poppet valve by a solenoid section the following pressure-receiving areas relating to the first poppet valve and the second poppet valve are set to be substantially equal to each other: the first effective pressure-receiving area of a first pressure-sensing spring device, the second effective pressure-receiving area of a second pressure-sensing spring device, the first pressure-receiving area on the inner side of a portion where a first valve seat surface and a first valve section surface are in contact with each other, and the second pressure-receiving area on the inner side of a portion where a second valve seat surface and a second valve section surface are in contact with each other.

Control valve

The control valve has a body; a supply port, an output port, and a discharge port; a first pressure-sensing device; the valve body having a first valve section surface that forms a first valve seat surface; a valve seat body having a second valve seat surface that forms the second valve section surface; a second pressure-sensing device; and a solenoid section. The first effective pressure-receiving area, the first pressure-receiving area on the inner side of a portion where the first valve seat surface and the first valve section surface are in contact with each other, and the second pressure-receiving area on the inner side of a portion where the second valve seat surface and the second valve section surface are in contact with each other are set to be substantially the same, and the second effective pressure-receiving area is set greater than the first effective pressure-receiving area.

The present invention enlarges the working pressure flowing into the working chamber and improves the response ability of the valve controlling the fluid using a compact solenoid portion. In the control valve according to the present invention, the first effective pressure receiving area of the first pressure sensing spring apparatus, the first pressure receiving area of the first poppet valve and the second pressure receiving area of the second poppet valve are made substantially equal while the second effective pressure receiving area of the second pressure receiving spring apparatus are made larger than the first effective pressure receiving area of the first pressure receiving spring apparatus; and the valve seat body co-operates with the first valve body to close and open the first poppet valve and the second poppet valve in accordance with a pressure of the working fluid flowing into the communication chamber from the third poppet valve when the third poppet valve is opened and the fourth poppet valve is closed by moving the solenoid rod forward.

A key distribution method and system for distributing a key over an insecure communication channel between first and second systems. Both first and second systems generate respective random numbers, calculate key distribution codes based on that random number, public information and information secret to the respective systems, and transmits the distribution codes to the other system. The same key is generated by both systems based on public information, the locally generated random number and the received key distribution codes. Alternatively, the systems may exclude the secret information from the key distribution codes but generate and transmit identification codes based on the secret information, public information and the locally generated random numbers. The received key distribution and identification codes are subjected to a known transformation and compared to known identification of the transmitting system.

Key distribution method

The amount of money which should be charged upon reception of a pay television signal or a like information signal, is calculated by a charging device comprising a calculator (25) for calculating the amount of charge and an encoder (28) for encoding the charge and time instant (date) using by a key code specific to the charging device to form a check code which should be reported together with the charge. The date data may be indicated either by a timepiece (26) or by a time signal multiplexed on the information signal. Cost information used in the calculator may be multiplexed on the information signal. Alternatively and preferably, the cost information is represented by a scrambling key used in providing the information signal.

Device for calculating a charge for a charged information signal with

A data converter applicable to data communications protects messages against errors and modifications by a third party. What is required for the detection of errors and modifications is simply causing a transmit station to add a particular pattern and a receive station to detect the particular pattern.

Data encryptor

A cryptographic system comprises a modulo-2 adder having a first input receptive of a sequence of binary digits to be scrambled and a second input receptive of a sequence of scrambling binary digits for generating a sequence of scrambled binary digits. A function generator having a memory is provided for storing a predeterminable sequence of binary digits in addressible storage locations and reading the stored binary digits in response to an address code represented by combined first and second patterns of binary digits which are generated respectively by a random pattern generator and a shift register which is connected to the output of the modulo-2 adder. The output of the function generator is the scrambling binary digits applied to the modulo-2 adder.

Cryptographic system

An enciphering key distribution system comprises a transmitter having an address generator for generating the addresses of those subscribers to which a first enciphered TV signal is to be distributed. An enciphering generator generates a second enciphering, in response to the individual addresses, on a one-to-one correspondence with the individual subscribers. A multiplier produces a product which is associated with all the subscribers. An adder adds the first enciphered signal to the product. The system also comprises a receiver having a divider for dividing the signal transmitted from the transmitter by one of the second encipherings on a basis which is assigned to the particular subscriber or receiver.

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Tokyo, Japan

Eiji Okamoto