Sumihatsu Co., Ltd.

Sumihatsu Co., Ltd. is a Japanese manufacturer specializing in the design and production of leaf springs, coil springs, and railway track-related products. Founded in 1960 in Amagasaki, Hyogo Prefecture, as Sumikin Hatsujo Co., Ltd., the company has evolved into a key production base within the Nippatsu (Nippon Hatsujo) group, the world's leading spring manufacturer. Sumihatsu operates three core business segments: leaf springs, coil springs, and railway track products. Its leaf spring business supplies suspension components to major domestic truck and commercial vehicle manufacturers, holding the top domestic share for truck and bus leaf springs. The coil spring business produces large hot-formed springs for construction machinery, industrial robots, and railway vehicles, including applications in elevators and even rockets. The railway track business, with roots in Yamamoto Hatsujo Bunkisha Co., Ltd., is one of Japan's oldest manufacturers of railway switches (turnouts), and also produces track components such as synthetic sleepers and balancers for overhead lines. The company relocated its manufacturing base to its current Tsukuba facility in 1981 and moved its headquarters to Sakuragawa City, Ibaraki Prefecture, in September 2020. As a consolidated subsidiary of Nippatsu, Sumihatsu produces over 50% of the group's leaf springs. It also maintains its own brand identity, designing and manufacturing products essential for construction machinery, industrial robots, and railway equipment. Sumihatsu emphasizes quality control, conducting up to 10 million operation tests for certain products, and invests in automated production lines. The company aims to be a leading enterprise in Ibaraki Prefecture and a source of local pride.

Sumihatsu Co., Ltd. was established in 1960 in Amagasaki, Hyogo Prefecture, under the name Sumikin Hatsujo Co., Ltd. The company was founded to manufacture springs, and it later came under the management participation of Nippon Hatsujo Co., Ltd. (Nippatsu), the world's leading spring manufacturer. In 1981, Sumihatsu consolidated its manufacturing operations at its current Tsukuba facility, marking a significant shift in its production base. Over the following decades, the company expanded its product lines and technical capabilities, becoming a key supplier of leaf springs to major domestic truck and commercial vehicle manufacturers. Its railway track business traces its origins to Yamamoto Hatsujo Bunkisha Co., Ltd., which is described as Japan's oldest manufacturer of railway turnouts (switches). In September 2020, Sumihatsu relocated its headquarters to Sakuragawa City, Ibaraki Prefecture, where its Tsukuba facility is located, starting a new chapter as a local enterprise. As a consolidated subsidiary of Nippatsu, Sumihatsu produces more than 50% of the group's leaf springs. It also maintains its own brand identity, designing and manufacturing products essential for construction machinery, industrial robots, and railway equipment. The company emphasizes quality control, conducting up to 10 million operation tests for certain products, and invests in automated production lines. It aims to be a leading enterprise in Ibaraki Prefecture and a source of local pride.

• 2020

  Relocated headquarters to Sakuragawa City, Ibaraki Prefecture, in September.

• 1995

  Sumihatsu Service Co., Ltd. established in August.

• 1981

  Consolidated manufacturing operations at the current Tsukuba facility.

• 1960

  Founded as Sumikin Hatsujo Co., Ltd. in Amagasaki, Hyogo Prefecture.

A specialized manufacturer of springs and railway track products, operating as a key production subsidiary of the Nippatsu group while maintaining its own brand for unique products.

• Leaf springs for trucks and buses

  Suspension components with domestic No.1 share, used by most domestic truck manufacturers.

• Leaf springs for steam locomotives

  Heavy-duty leaf springs (担ばね) supporting the horsepower of steam locomotives, designed and manufactured based on actual parts and customer consultations.

• Leaf springs for rally cars

  Tuned leaf springs for rally-spec pickup trucks, pursuing strength and weight reduction.

• Coil springs for construction machinery

  Hot-formed coil springs used in crawlers of excavators and bulldozers to prevent detachment and absorb shock.

• Coil springs for industrial robots

  Springs that assist motor torque loads for precise and rapid movements of industrial robot arms.

• Coil springs for railway vehicles

  Coil springs supporting the undercarriage of trains from conventional lines to Shinkansen, improving ride comfort.

• Coil springs for elevators

  Three types of springs used in elevators: fastening leaf springs for guide rails, U-springs for emergency speed suppression, and coil springs as cushions at the bottom.

• Coil springs for rockets

  Springs adopted in domestic rockets, designed to function accurately under harsh environments and meet weight criteria.

• Railway turnouts (switches)

  Turnouts that branch railway tracks and change vehicle direction, handled consistently from design to manufacturing and assembly.

• Railway track components

  Synthetic sleepers, rail fastening devices, and other parts constituting railway tracks.

• Balancers for overhead railway lines

  Spring-type balancers that keep tension constant in overhead lines, absorbing expansion and contraction for maintenance-free operation.

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5. 5Sumihatsu Co., Ltd. (Japan) - Wikidatawikidata.org