Abstract: A machine tool has a table body and a drive line on a bed. The table body is linearly movable via a guide member having a sliding or rolling guide surface. The drive line has a ball screw or the like, and moves the table body along the guide surface. A pair of guide members are provided at positions in point symmetry about the position of the center of gravity of the table body. Moreover, a pair of drive lines having the ball screws or the like are provided at positions in point symmetry about the position of the center of gravity of the table body. Alternatively, drive line having the ball screw or the like is provided at the position of the center of gravity of the table body.

Abstract: A spindle apparatus of a machine tool comprises a main spindle rotatably supported in a housing via bearings. A helium circulation system is provided for introducing helium, lower in density and fluid pressure than air, through a helium supply port into a gap on the outer periphery of the main spindle within the housing, and for discharging helium to the outside through a helium discharge port. The main spindle is rotated in an atmosphere of the helium. The spindle apparatus is simple in structure, but can minimize the power loss of the main spindle and reduce the motor power, and also gives a cooling effect.

Abstract: A spindle apparatus of a machine tool comprises a main spindle rotatably supported in a housing via bearings. A helium circulation system is provided for introducing helium, lower in density and fluid pressure than air, through a helium supply port into a gap on the outer periphery of the main spindle within the housing, and for discharging helium to the outside through a helium discharge port. The main spindle is rotated in an atmosphere of the helium. The spindle apparatus is simple in structure, but can minimize the power loss of the main spindle and reduce the motor power, and also gives a cooling effect.

Abstract: A machine tool has a table body and a drive line on a bed. The table body is linearly movable via a guide member having a sliding or rolling guide surface. The drive line has a ball screw or the like, and moves the table body along the guide surface. A pair of the guide members are provided at positions in point symmetry about the position of the center of gravity of the table body. Moreover, a pair of the drive lines having the ball screws or the like are provided at positions in point symmetry about the position of the center of gravity of the table body. Alternatively, the drive line having the ball screw or the like is provided at the position of the center of gravity of the table body. The machine tool can effectively suppress vibrations of a structure (such as the bed) generated during movement of a moving object (such as the table body) relative to the structure by the drive line, thereby shortening the machining time and increasing productivity.

Abstract: A machine tool has a spindle head and ball screws on a saddle. The spindle head is provided via sliding or rolling guide members so as to be linearly movable. The ball screws move the spindle head along the guide members. Concave sliding or rolling guide portions parallel to the guide members are provided on both sides of the guide members. Counterweights linearly movable on the concave guide portions in a direction opposite to the spindle head are provided. Racks are provided on opposed surfaces of the counterweights and the spindle head along the directions of movement of the spindle head and the counterweights. Pinions meshing with the racks are rotatably supported in the saddle. The machine tool can effectively suppress vibrations of a structure (such as the saddle) generated during movement of a moving object (such as the spindle head) relative to the structure by a drive line (such as the ball screws), and always keep the center of gravity of an entire relatively moving portion constant.

Abstract: A crane system for carrying a load while suspending it from a portal-shaped body frame via wire ropes includes first and second wire ropes on both sides, in a right-and-left direction, of an upper portion of the body frame for fixing the suspended load, and means for taking up and paying out the first and second wire ropes. The system also includes means for winding the first and second wire ropes in opposite directions, or winding them in the same direction. The first and second wire ropes may be looped together with the means of taking up and paying out the wire ropes. Connection points or sheaves may be provided on the suspended load. It is also permissible to route the first and second wire ropes parallel to each other. Further, the above takeup and payout means may be in a tapered drum form.

Abstract: A crane apparatus is disclosed. A hoisting accessory is traversed by rotating rotating drums by driving of a traversing motor to take up or pay out wire ropes. Continuously variable transmissions are provided for changing rotational speeds of the rotating drums. A control device controls the continuously variable transmissions in a gear changing manner so that forces imposed on the drums by the wire ropes will be balanced. Thus, torques acting on the pair of drums are canceled out in all areas in which the hoisting accessory moves, whereby the capacity of the drive motor can be reduced.

Abstract: A crane apparatus is disclosed. First traverser wire ropes are connected to a right connecting portion of a traverser, while second traverser wire ropes are connected to a left connecting portion of the traverser. First hoisting accessory wire ropes are passed over a right rope pulley via the traverser, and then connected to the traverser, while second hoisting accessory wire ropes are passed over a left rope pulley via the traverser, and then connected to the traverser. A hoisting accessory is suspended from the right and left rope pulleys. The crane apparatus enlarges the traversing range of the hoisting accessory, and increases work efficiency, without becoming upsized.

Abstract: In the present invention, in cutting the top and bottom surfaces of a hot-rolled sheet by the rotation of milling cutters holding the sheet therebetween in the thickness direction of the sheet in the running process of the hot-rolled sheet, the cutting resistance determined by the cutting conditions including the type of hot-rolled sheet, the temperature in cutting, and the cut depth is controlled by the adjustment of cut depth, and cutting is performed by making the tension produced on the hot-rolled sheet by the cutting resistance lower than the breaking strength of the joint portion to prevent the breakage of hot-rolled sheet.

Abstract: In the present invention, in cutting the top and bottom surfaces of a hot-rolled sheet by the rotation of milling cutters holding the sheet therebetween in the thickness direction of the sheet in the running process of the hot-rolled sheet, the cutting resistance determined by the cutting conditions including the type of hot-rolled sheet, the temperature in cutting, and the cut depth is controlled by the adjustment of cut depth, and cutting is performed by making the tension produced on the hot-rolled sheet by the cutting resistance lower than the breaking strength of the joint portion to prevent the breakage of hot-rolled sheet.

Abstract: A surface cutting apparatus for hot-rolled products cuts top and bottom surfaces of a hot-rolled steel product continuously or intermittently by passing the steel product between a pair of rotary drums (milling cutters) that rotate in a direction reverse to each other. The apparatus includes a disk having a larger diameter than that of the rotary drums at one or both ends of at least one of the rotary drums. The disk recognizes a gap between the rotary drums, allowing a zero adjustment to be made without excessively pressing the rotary drums. The measurement can be by a non-contact distance meter, eddy-current type sensor or other sensor.

Abstract: A surface cutting method for a hot-rolled steel product that includes a joint portion having a predetermined breaking strength includes a step of clamping the steel product between a pair of milling cutters that are arranged on top and bottom surfaces of the steel product, while the steel product is conveyed in a longitudinal running direction. The top and bottom surfaces of the steel product are subjected to cutting by rotating the milling cutters in a rotating direction. A cutting resistance applied to the milling cutters during the cutting is determined based on parameters including type of steel, width, thickness, surface temperature and conveying speed of the steel product, as well as circumferential speed and cutting depth of the milling cutters.

Abstract: Upon roll-forming an end plate of hemispherical and other cup-like or dish-like configurations, a raw material disc is placed between outer die means consisting of a top outer forming die that can be vertically moved by a drive source and can be freely rotated and at least a pair of left and right outer forming rolls adapted to move along predetermined moving paths and inner die means consisting of a top inner forming die held at a predetermined position that can be driven in rotation by a drive source, and a middle inner forming roll a bottom inner roll both of which are freely rotatable, the outer die means is depressed against the inner die means, and said pair of outer forming rolls are moved along said moving paths so as to press said raw material disc against the middle inner forming roll and the bottom inner forming roll, respectively, one of said outer forming rolls being moved within an effective forming range of the middle inner forming roll, while the other being moved within an effective forming r