Gas Springs and Shock Absorbers

Operations on a gas spring cylinder

The cylinder of a gas spring (tailgate strut, hood strut, chair gas lift, hydraulic damper) or shock absorber is a precision steel tube worked at both ends: one end closed or closed with a hole for a fitting, the bore grooved for speed and damping control, the other end pressed with guide and seals then rolled over, and sometimes an end screw locked on. TONG DA has a machine for each step.

TD-31040 gas spring cylinder closing machine
TD-31040 gas spring cylinder closing machine		TD-627 servo inner grooving machine
TD-627 servo inner grooving machine		TD-42815 gas spring roll grooving machine
TD-42815 gas spring roll grooving machine

The TONG DA cylinder line

OperationMachineNote
Cylinder end closingTD-31040 hydraulic 3-stationCold roll-spun one-piece closed end or center hole, no welding
Inner groovingTD-627 servo / TD-61530Longitudinal oil grooves on the bore for damping and speed
External groovingTD-42815 hydraulic rollingOD grooves and beads
Component pressing and edge foldingTD-AT155Press in guide and seals, roll the mouth over
Lock nutTD-91528Pneumatic end-screw tightening, single or two-station
Edge folding and punchingTD-738Tube end folding and punching

Buy one machine to fill a gap in an existing line, or plan the whole line with TONG DA.

Why gas spring makers choose TONG DA

  • Closing, grooving and assembly machines from one supplier, already matched to each other
  • TONG DA also runs contract production, so it knows what goes wrong on a cylinder line
  • Jaws, collets and hydraulic chucks supplied as spares long term
  • Building since 1989, CE certified, machines sold to the USA, Germany, Turkey, the UK, India, China and more

How to start

Send cylinder OD × wall × material × length, the closed-end and groove drawings and expected volume. TONG DA recommends models and trial-runs your tubes before you decide.

Related videos

TD-31040 Gas Spring Tube Closing – OD15/18/21 on One Machine
TD-31040 Gas Spring Tube Closing – OD15/18/21 on One Machine		Servo CNC Gas Spring Damping Groove (Inner Grooving) Machine
Servo CNC Gas Spring Damping Groove (Inner Grooving) Machine		TD-42815 Roll Grooving for Gas Spring / Tailgate Strut Tubes
TD-42815 Roll Grooving for Gas Spring / Tailgate Strut Tubes

More machine videos on our YouTube channel: youtube.com/@closingmachine

Planning a complete gas spring line?

See gas spring production line: tube cutting, damping groove, ring groove, bottom closing, oil filling, press-fit and folding, gas charging and end fittings. Spare jaws, guide tubes and chucks: spare parts.

Shock absorbers and dampers

Cylinder bottom closing, grooving, valve riveting machines and piston rod preparation: see shock absorber manufacturing machines.

TD-31040 Pipe End Closing Machine | Tube Spinning & Roll Closing, Hydraulic 3-Station
TD-31040 Pipe End Closing Machine | Tube Spinning & Roll Closing, Hydraulic 3-Station
Pipe end closing machine / tube spinning machine for gas spring, tailgate strut and shock absorber manufacturers. TD-31040 is TONG DA’s patented hydraulic 3-station tube end closing machine. It cold-forms the open end of a metal tube into a fully closed dome, or a dome with a center hole of specified diameter, by roll spinning. No heating, no welding, no plastic plugs. Tube OD 10–40 mm, wall 0.8–2.0 mm, in carbon steel, stainless steel, copper and aluminum. Three stations cycle in turn, so one operator runs the machine without special skill. Typical products: gas spring and tailgate strut cylinders, shock absorber tubes, heat exchanger tubes, furniture and stroller frames.
Stabilizer Bar & Torsion Beam Production Line | Hollow Stabilizer Bar Tube Equipment
Stabilizer Bar & Torsion Beam Production Line | Hollow Stabilizer Bar Tube Equipment
Production line equipment for hollow stabilizer bars, torsion bars and torsion beams: weld-seam inner drilling with engraving, tube expanding, hot upsetting of tube ends, end turning and NC end closing. Built to each part, exported overseas for automotive mass production.
TD-31050 Shock Absorber Tube Closing Machine | Two-Station Pipe End Closing, Ø15–50 mm
TD-31050 Shock Absorber Tube Closing Machine | Two-Station Pipe End Closing, Ø15–50 mm
TD-31050 is a patented hydraulic two-station arc-top closing machine for tube OD Ø15–50 mm and wall 0.8–3.0 mm. It cold roll-spins the tube end fully closed or with a center hole – no heating, welding or plastic plug. PLC touch control, inverter spindle speed and a strengthened forming unit make it suited to shock absorber cylinders and larger tubes.
TD-311 / TD-332 Automatic Tube Sealing Machine | Auto-Feeding Single-Station Pipe End Closing
TD-311 / TD-332 Automatic Tube Sealing Machine | Auto-Feeding Single-Station Pipe End Closing
TD-311 (also called TD-332) is a single-station auto-feeding tube closing machine for gas spring and gas lift cylinders Ø15–28 mm, wall 1.0–2.0 mm, length 100–500 mm. Tubes are fed from a hopper, closed and unloaded automatically; the end is cold roll-spun into a dome with adjustable arc and hole – no weld or plug. Hydraulic clamping and PLC touch control for high-volume production.
TD-876 Tube End Reducing / Swaging Machine | Tube Shrinking Machine
TD-876 Tube End Reducing / Swaging Machine | Tube Shrinking Machine
TD-876 is TONG DA’s tube end reducing (swaging / shrinking) machine. It reduces the outer diameter of a metal tube end for telescoping and push-fit joints, or as a forming step before end closing. Contract tube reducing is also available on our own machines.
TD-21025 Flat-End Tube Closing Machine | Flat Sealing for Furniture, Heat Pipes & Strollers
TD-21025 Flat-End Tube Closing Machine | Flat Sealing for Furniture, Heat Pipes & Strollers
TD-21025 is a patented hydraulic flat-end tube closing machine. It cold roll-spins a metal tube end into a flat closed bottom or one with a center hole – no heating, welding or plastic plug, with a smooth, safe finish. For furniture, baby chairs and strollers, heat pipes and heat exchanger tubes; PLC touch control.
TD-31040 Tube End Closing Machine for Furniture, Strollers & Outdoor Chairs | Replaces Plastic Plugs
TD-31040 Tube End Closing Machine for Furniture, Strollers & Outdoor Chairs | Replaces Plastic Plugs
TD-31040 closes tube ends on furniture, chairs, strollers, cribs, outdoor loungers, wheelchairs, crutches, telescopic poles and lighting. The open end of a steel or aluminum tube is cold roll-spun into a smooth dome, replacing plastic end plugs and welded caps: nothing to fall out, no sharp edge, no grinding before plating or coating. Machine range Ø10–40 mm, wall 0.8–2.0 mm; heavy-wall or special tubes can be evaluated on sample.
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