Abstract: An object of the present disclosure is to provide an abrasive pad that is superior in abrading performance and abrasive slurry discharging properties. An abrasive pad having an abrading part and a groove part on an abrasive surface is provided in which a surface of the groove part has a non-foamed part, and a foamed part is exposed on a surface of the abrading part.

Abstract: An air extracting system for a hydraulic steering apparatus which has a pump, a reservoir and a piston-cylinder mechanism which is geared to the steering gear. A two-position changeover valve is positioned in the hydraulic circuit between the pump and the piston cylinder mechanism, which in one position connects them in a closed circuit and in the other position connects the return portion of the hydraulic circuit to the reservoir. The piston has a bore therethrough with a two way check valve therein with a check valve opening element which opens the check valve at the end of the stroke of the piston. When the changeover valve is positioned to connect the return of the hydraulic circuit to the reservoir, when the piston reaches the end of its stroke, the check valve is opened to cause air in the system to pass through the check valve and through the changeover valve to the reservoir.