Use clamps/mandrels correctly – tension torsion springs safely
For professionals and specialist companies only. Torsion springs are subject to high energy. Work only with suitable tools, correct procedures, and personal protective equipment.
Products & Applications
Mandrel Garage / Service
- Spring mandrel garage
- Ø 12.7 mm (hollow) , length 400 mm – for 51 mm and 67 mm torsion springs.
- Available individually or in packs of 10/25/box.
Mandrel Industry / Heavy Duty
- Spring mandrel industrial – 20 mm
- Ø 20 mm (solid) , length 850 mm – for 95 mm and 152 mm torsion springs.
- Available as a set or in a box (5 sets).
Material: hardened tool steel – robust & durable. For a complete overview: Clamping irons/mandrels collection .
Note: The rod diameter must exactly match the cone bore. Do not use makeshift tools (screwdrivers/pipes). Observe increased safety precautions!
Safety guidelines (non-negotiable)
CAUTION: Working on torsion springs is a high-risk activity. Only trained personnel should use PPE (eye/hand protection), LOTO/separation, and approved tools.
- LOTO & separation: De-energize the drive, release the mechanical coupling, secure the gate against movement.
- 2-rod rule: Always use two tension rods simultaneously; never work with just one rod.
- Body position: Work sideways; no body parts in the rotation/swivel area.
- Fit: Only bars with the right diameter and sufficient length/grip (garage 400 mm; industry 850 mm).
- Preliminary inspection: Check cones/screws, shaft, bearing blocks, rolling direction, drums – no cracks/chips.
- Secure the area: Keep people out of the danger zone. Barrier/mark the area. Observe increased safety precautions!
Pro‑Process: Tensioning / relaxing springs
Basic logic outlined for trained technicians. Manufacturer specifications (turns, direction of rotation, torque, sequence) always take precedence.
A. Preparations
- Position the gate securely (mostly closed), disconnect the drive electrically/mechanically (LOTO), secure the gate against movement.
- Expose the cone holes, confirm the direction of rotation (L/R), locate the clamping screws.
- Check clamps (straightness, edges, handles). Use only intact tools.
B. Relaxation (e.g. spring change)
- Insert the first rod completely; loosen the clamping screws only enough to ensure that the cone remains guided.
- Insert the second rod into the next hole; release the spring in 90° increments . One rod always remains in the cone as a barrier.
- After complete relaxation: secure the cone, disassemble the spring/shaft according to the manufacturer's instructions.
C. Clamping (commissioning)
- Ropes correctly on drums, rope tension symmetrical. Position cone, tighten clamping screws (not yet fully tightened).
- Insert the first rod, preload the spring in 90° increments to the desired turns; use the second rod as counter-hold.
- Secure the clamping screws to the specified torque. Test and balance the handrail; adjust in 1/4-turn increments if necessary.
Typical sources of error & countermeasures
| Mistake | risk | Pro-countermeasure |
|---|---|---|
| Incorrect rod diameter / makeshift tool | Rod slips out of cone → serious injuries | Only use Ø 12.7 mm (garage) or Ø 20 mm (industry) to match the cone bore. |
| One-staff work | Uncontrolled reverse rotation | Always two rods; one works, one secures. |
| Body in the swivel range | Hit by rod/spring/shaft | Lateral position, defined grip, PPE. |
| Clamping screws loosened incorrectly/too early | Sudden relaxation | Only loosen under bar protection and in the correct order. |
| Turns/Balance ignored | Over/undervoltage → damage | Manufacturer's setpoints; fine adjustment in 1/4-turn increments. |
How clamps/mandrels are manufactured
- Raw material & cutting: Selection of hardened tool steel, lengths e.g. 400 mm (garage) / 850 mm (industrial).
- Finishing: Deburring/edge radius for secure fit in the cone bore; optional grip/knurling zones.
- Heat treatment: Hardening/tempering for tough, fracture-resistant properties.
- Surface protection & testing: Protective coating, visual and straightness inspection; if necessary, sample tensile testing.
- Set packaging: Individually/set/carton – suitable for the application profile (garage/industry).
Safety conclusion: Tool quality and correct procedure are crucial. Increased safety considerations – always!
FAQ
Can I work with 12 mm round steel?
No. Only use form-fitting rods of the appropriate diameter (e.g., 12.7 mm for garages / 20 mm for industrial use). Anything else is a safety risk.
Why “two sticks”?
At 90° increments, one rod remains in the cone as a lock, while the second moves in a controlled manner. This prevents kickback.
When to replace?
In case of nicks, bends, damaged handles, or after a fall. Tools are safety-critical.
