in the lubricant cell 40 by the stop member 48 which seals off the open end of the lubricant cell 40 the covering member 46 and stop member 48 are suitably positioned centrally of the bolt within a well portion 50 defined in the face of the bolt the well is suitably formed as a bevel so as to define a depth 52 between the top of the covering member and the outer face of the bolt 30 the first blade and second blades 32 are held together in pivoting relation by the pivot lubrication bolt 30 in conjunction with a nut 54 and two washers 56 serving to reduce friction between the blades and the nut in use as the covering member 46 is pressed against the coil spring 44 a gap is created between the covering member 46 and the stop member 48 in view of the covering member 46 being partially moved out of contact with the stop member 48 a lubricant such as oil for example may then be injected into the lubricant cell 40 via the gap the well portion 50 provides a holding area to receive the lubricant temporarily until the lubricant may pass by the covering member into the lubricant cell 40 this enables an easier re supply of the lubricant cell without the likelihood that the lubricant will spill beyond the extent of the bolt especially in the case where the lubricant supply nozzle is not precisely inserted into the opening of the stop member in use.