Abstract: A top cover is made of a metal and constituted to provide substantially a bowl-like shape extended from an upper side of an exhaust cover in a side direction. Further, a damping member including an elastic member is provided between the top cover and the exhaust cover. Further, an expansion chamber constituting a space of communicating with an exhaust path and the exhaust port for communicating the expansion chamber to the atmosphere are provided and the damping member is provided to be pinched with an exposed thread at a surrounding of the expansion chamber.

Abstract: A magazine cover is integrally molded with a return-preventing claw part to be engaged with a fastener loaded into a guide part. The return-preventing claw part is so constructed as to include: a return preventing surface that abuts against the fastener to prevent the fastener from moving to a loading port; and a support portion that always makes the return preventing surface abut against the fastener, thereby being deformed, to support the return preventing surface such that the return preventing surface can be retracted to a position where the return preventing surface does not abut against the fastener.

Abstract: A fastener driving tool includes: a driver blade adapted to drive nails joined to one another into an object in order; a nose adapted to guide the driver blade and nails; and a guide surface of a projection adapted to guide a head portion of a first nail struck out into an exit hole of the nose so that the second nail is not exposed to the exit hole. The guide surface of the projection is formed to a shape identical with that of the head portions of the nails.

Abstract: A fastener driving tool includes: a driver blade which is driven by compressed air so as to move in a vertical direction for striking a fastener such as a nail, an injection hole which guides said driver blade and forms a passage for the compressed air to be exhausted along with the movement of the driver blade, and a magazine for supplying the fastener to said injection hole, wherein an exhaust passage through which an interior of the injection hole is communicated with the atmosphere is provided between a lower end of the driver blade when the driver blade is positioned at a top dead center and a head part of the fastener which has been supplied into the injection hole.

Abstract: A nail gun is capable of making wear resistance and light-weighted formation compatible with each other by enabling to make a wall thickness of a body or the like as thin as possible by providing a plurality of projected portions having heights in correspondence with wear limits of respective portions at respective portions of a body a head guard for guarding an exhaust cover and the like and reducing wear other than the projected portions.

Abstract: A fastener driving tool having a magazine device including a magazine and a nail feeder. The magazine extends in a first direction and defines an accommodation portion for accommodating therein a fastener array. Each fastener has a shaft with a sharp-end and a head connected to the shaft. The plurality of fasteners are directed in a second direction perpendicular to the first direction and positioned side by side to form the fastener array extending in the first direction. The magazine has one end and another end in the second direction. One end is close to the sharp end of the fastener and another end is close to the head of the fastener. The accommodation portion includes an expanding portion having a width in a third direction perpendicular to the first direction and to the second direction. The width is gradually increased from the one end toward the other end.

Abstract: A pneumatically operated fastener driving tool capable of reducing a time period from operation timing of a trigger to downward movement of a driver blade for fastener driving, and reducing a time period from the release timing of the trigger to a timing at which respective components are returned to their initial positions for a subsequent nail driving. As components a main valve and a trigger valve is provided. The main valve is movable within a main valve chamber connected to a main valve control channel. The trigger valve selectively provides fluid communication between the accumulator and a main valve chamber through the main valve control channel and between the main valve chamber and the atmosphere through the main valve control channel. A ratio of cross-sectional area of the main valve control channel to an internal volume of the main valve chamber is defined to a specified ratio.

Abstract: Non-porous spherical silica having a mean particle diameter of 0.

Abstract: The reading timing determination unit determines a timing at which identification marks such as print bar codes should be read. The reading unit reads identification marks in accordance with the timing to provide identification mark data in a numerical form. The discrimination unit compares identification mark data with data value of an identification mark to be primarily printed to judge whether or not the identification mark is correctly printed. The signal generation unit produces a notifying signal when it is judged that the identification mark is not correctly printed. In this way, this apparatus tests whether or not identification marks successively printed on a moving body in the form of sheet by the printing machine are correctly printed.

Abstract: A method for purifying a reaction solution obtained by using a microbial cell, an immobilized microbial cell, or an immobilized enzyme as a catalyst in a water medium is disclosed. The method comprises repeatedly filtering the reaction solution to remove fine solid matter using a polyethylene porous hollow fiber membrane having a bubble point of from 1 to 20 kg/cm.sup.2, and repeatedly washing the hollow fiber membrane before it has been clogged to such an extent that a differential pressure thereof exceeds 3 kg/cm.sup.2. By this method, a filter membrane can be repeatedly regenerated at high efficiency and can stably be used for a long period of time.

Abstract: A method for purifying an aqueous acrylamide solution by using activated carbon is disclosed. The method comprises contacting activated carbon with water having oxygen dissolved therein until the dissolved oxygen concentration in water after the contact increases to at least 0.5 ppm, and then contacting the aqueous acrylamide solution with the thus treated activated carbon. The method can prevent polymerization of acrylamide around activated carbon, and the resulting purified aqueous acrylamide solution requires no further purification, such as ion-exchanging.

Abstract: This invention deals with a process for manufacturing high purity silica which comprises making an aqueous alkali silicate solution into fine fibrous gel in a coagulant, treating the fibrous gel obtained with an acid-containing solution, and then with water to extract and remove impurities; and optionallly heating a resulting silica at a temperature of 1,000.degree. C. or higher. Thus obtained silica is preferably used as a filler, especially, the one for resin compositions for encapsulating electronic parts; etc.