Unirope provides the service of replacing existing crane buttons at our fabrication plant facilities in Edmonton (AB), Mississauga (ON) and Montreal (QC).

Events need to be scheduled and coordinated with your local Unirope Plant Manager.

Button replacement event in Edmonton.
Button replacement on two mobile cranes at the same time at our Edmonton plant.
Button replacement event in Mississauga.

Alternatively, if the crane is already set up at and can’t be easily moved you can unbolt the entire rope winch and sent it to Unirope. We will attach a new button including proof testing.

Because we can’t spin the drum make sure that enough slack rope is provided or, make sure that the old button passes around the drum without interference from the rope guards.

We also provide the service to “field install” our Torpedo Buttons onto your crane rope. Note that this is not possible at any weather conditions, especially at sub-zero temperatures at/or during snow and ice storms. One of the reasons is that the rope, button and the WireLock® resin need to have the same temperature.

Proof Testing Requirements

Why Proof testing?

Proof testing is part of the Torpedo Button installation quality verification procedure. Proof testing is done to twice the permissible (WLL) rope tension/load. As crane ropes are used at a DF of 5:1 this means we proof load to 40% of the Minimum Breaking Strength (MBS) of the rope.

The second reason is that at this proof load the resin cone inside the sockets is fully “seated”. This prevents that the cone spins or separates from the button before the first load is applied.

If you receive an installed button and you can spin the cone by hand that means that the button had never been proof tested.

The third reason are requirements by applicable Standards.

A. CSA Z 150-16 MOBILE CRANES and CSA Z 248-17 TOWER CRANES require to proof test all installed spelter fittings.

B. ASME B30.30 ROPES Under clause 30-1.7.4 k) two different types of proof tests are required:

  1. Proof testing to 40% of the MBS of the rope when the rope was installed at the rope fabricators plant, or
  2. Proof testing to 95% of the permissible maximum line (rope) pull (19% of MBS at DF 5:1) of the crane winch if the button was installed ‘in the field’ and no mobile test bed was available.

Unirope purpose designed Torpedo Proof Testing fitting.
Proof Test Equipment (Mississauga)

Note that in Ontario Unirope has available mobile test beds with rope grippers to proof test any installed crane rope button in the field. However, we highly recommend that if your button was field installed WITHOUT a proof load to 40% of MBS you bring in your crane after your job is done so that we can proof load the spelter button in our shop test bed.
Rope grip installed in our mobile test bed