Provided are a forming method for an arc spring, capable of easily and surely locating bearing faces on both end faces of a semi-finished product in predetermined positions, the bearing faces having lengths within permissible ranges in a circumferential direction. For a semi-finished product prior to curving an axis, it is determined whether circumferential lengths of bearing faces on both end faces are respectively within the permissible ranges based on end face image information of the both end faces imaged in an axial direction prior to the curving, a circumferential rotational position of the semi-finished product capable of respectively locating the bearing faces within the predetermined positions is specified using the end face image information, and the semi-finished product is rotated to the specified rotational position, and the wedge part is sequentially driven into inter-wires of the semi-finished product to deform the semi-finished product.

A wire forming apparatus 1 comprises a rotary table 22 that is rotatably supported by a table body 21, a slide tool unit 100A that is attached to the rotary table 22 and supports a slide tool T1 capable of sliding toward a wire guide, and a tool slide mechanism 60 that is supported by the table body 21 and transmits a driving force for sliding the slide tool T1 to the slide tool unit 100A. The tool slide mechanism 60 has a single motive power transmission member 61 that is rotatably supported by the table body 21, and a driving force generated by a rotation of the motive power transmission member 61 is transmitted, in common, to a plurality of slide tools T1 attached to the rotary table 22.

An upholstery spring comprises a steel spring wire made of a microalloyed steel and a color indicator arranged thereon at least in some regions, the microalloyed steel containing between 0.004 to 0.015 wt.-% of one or more alloy elements. The invention further relates to a method for producing an upholstery spring, a mattress or a piece of upholstered furniture having such an upholstery spring.

An upholstery spring comprises a steel spring wire made of a microalloyed steel and a color indicator arranged thereon at least in some regions, the microalloyed steel containing between 0.004 to 0.015 wt.-% of one or more alloy elements. The invention further relates to a method for producing an upholstery spring, a mattress or a piece of upholstered furniture having such an upholstery spring.

Provided is an electrical dust-collecting filter manufacturing method and an electrical dust-collecting filter. The method includes the steps of: preparing a frame body, a dust-collecting electrode, a discharge electrode, and a discharge frame; assembling the dust-collecting electrode into an assembly hole of the frame body; connecting the discharge frame to the frame body via an insulating member; and arranging the discharge electrode in an axial direction inside the dust-collecting electrode via the discharge frame and fixing the same. The dust-collecting electrode assembling step includes: temporarily elastically deforming the dust-collecting electrode in the radial direction and inserting the same into the assembly hole of the frame body; and pressurizing end parts of both ends of the dust collecting electrode, which protrude out of a plate member when fitted into the assembly hole, in the axial direction such that the end parts are compressed against the surface of the plate member.

Provided is an electrical dust-collecting filter manufacturing method and an electrical dust-collecting filter. The method includes the steps of: preparing a frame body, a dust-collecting electrode, a discharge electrode, and a discharge frame; assembling the dust-collecting electrode into an assembly hole of the frame body; connecting the discharge frame to the frame body via an insulating member; and arranging the discharge electrode in an axial direction inside the dust-collecting electrode via the discharge frame and fixing the same. The dust-collecting electrode assembling step includes: temporarily elastically deforming the dust-collecting electrode in the radial direction and inserting the same into the assembly hole of the frame body; and pressurizing end parts of both ends of the dust collecting electrode, which protrude out of a plate member when fitted into the assembly hole, in the axial direction such that the end parts are compressed against the surface of the plate member.

The present invention provides a spring manufacturing machine including a wire guide member configured to guide a wire along a conveying direction to a first base point or a second base point for forming a spring, and a pair of movable assemblies configured to allow the second base point to be located between the first base point and the pair of movable assemblies. Each of the movable assemblies comprises a mounting platform configured to move close to or away from the first base point or the second base point along the conveying direction. Each mounting platform has a recess, and two mounting platforms are adjacent to each other to allow their respective recesses to surround the second base point, so that the movement of the mounting platforms do not to interfere with operation at the second base point.

Apparatus is provided for metallurgical heat treatment of coil springs, or similarly shaped workpieces and articles of manufacture, by electric resistance heating along the entire length of the workpiece so that the ends of the workpiece can be heat treated to the same degree and quality as the section of the workpiece between its two ends.

Apparatus is provided for metallurgical heat treatment of coil springs, or similarly shaped workpieces and articles of manufacture, by electric resistance heating along the entire length of the workpiece so that the ends of the workpiece can be heat treated to the same degree and quality as the section of the workpiece between its two ends.

A spring forming apparatus is shown generally at 200, in which metal wire 220 is fed from a supply (not shown) by feed rollers 230, via irregularity-effecting rollers 240 to a forming station 250. The forming station comprises a first deflector 260 and a second deflector 270. When the spring S is complete, it separates automatically from the rest of the wire 220 due to the presence of an irregularity 280, without the need for a cutter device.