22.10.2 Type (2)

  1. Never use less than two clamps and always ensure that they face each other to balance out the horizontal clamping forces.

  2. Always work within the angles and reeve in the manner recommended by the manufacturer. Some clamps are ineffective outside the recommended angles but in addition, excessive forces may be imposed on the clamps or the sling legs. Changing the method of reeving will effectively change the angles and thereby affect the gripping action and the forces imposed. These factors are particularly important in the case of the open or camless type of clamp as shown in Figure 22.4.2-1  b.

  3. If the plates to be lifted are likely to sag longitudinally, use two or more pairs of clamps in conjunction with a lifting beam. The position and number of clamps should be adjusted to minimise the sag. Where multipoint lifting of this sort is carried out, account should be taken of the recommendations made in section 1, 1.9 SAFE USE OF LIFTING EQUIPMENT of this code.

  4. Unless specially designed for the purpose, horizontal plate lifting clamps should not be loaded at an angle to the side plate of the clamp. This will normally restrict them to use with a two leg sling.

  5. If the plates to be lifted are likely to sag transversely, then clamps which grip the plate by a cam or toe must be used. In any event, care should be taken to ensure that the plate or plates will not collapse under the horizontal compressive force. In this context, it should be remembered that clamps reeved onto an endless loop will exert a greater compressive force, for a given angle between the legs than those attached to a two leg sling.