Details

INSTALLATION & MAINATENANCE OF HEADGEAR SHEAVES

Installation and maintenance of headgear sheaves (Cir. 68/1973)

Headgear sheaves have been found in use with excessively worn grooves, cracked or loose spokes which not only affect the winding ropes but are also very dangerous. The
sheaves constitute a vital part of the winding installation and therefore, should be given necessary attention and care.
Reg. 78(4) (b) of CMR 2017 and corresponding Reg. 80(4) (b) of MMR 1961 specify that the grooves of the sheaves or puleys shall be suited to the diameter of rope but this aspect
is hardly checked either during the installation or during maintenance inspections.
The following shall be complied with in respect of all winding installations at every mine

(i) The sheaves should be sufficiently strong in construction to withstand nor the maximum pressure exerted by winding ropes under most severe conditions, but should
not be very heavy to cause slipping on the rope due to inertia.
(ii) The tread or the groove should amply support the rope, and a support up to 120° on the groove is considered satisfactory.
(iii) The sheave flanges should be strong to safely withstand the pressure of the moving rope and should be adequate to prevent the rope from slipping off the sheave,
(iv) For round and flattened strand ropes radius of the sheave groove should be equal to the radius of the rope plus 10% and for locked coil ropes the groove radius should be
equal to the radius of the rope plus 5%.
(v) During inspection of the sheave interalia shape of the groove and its tread thickness should be properly checked.
The following schedule of inspection should be normally followed for head-sheaves etc .-
1. The shape of the sheave groove and minimum thickness of material on the tread (between two spokes) should be correctly measured whenever a new sheave is installed.
For shape of the groove suitable plaster mould should be taken and a drawing of the groove can be made from the mould for future comparison. The measurements should be
recorded in a paged register.
2. The groove and thickness of material on tread should thereafter be regularly checked at interval of not more than six (06) months. Each time a drawing of the groove should be
made and compared with the original drawing. Any variation, due to wear or any other reason, should be clearly recorded in the inspection register. The minimum thickness of
material on tread should also be recorded.
3. Inspection of the groove and tread should also be made nearly three (03) months before the due date of replacement of the winding rope working on the sheave so that, if
necessary, the sheave can be corrected or replaced for the new rope.
4. Besides the above, routine inspection of general condition of the sheave, spokes, axle and bearings etc. should be made at least once every seven (07) days and the findings
should be recorded in the register.
All reports of inspections mentioned above should be examined by the Colliery Engineer and signed by the Manager and the Engineer.