down to complete the fastening the type of fastening means 7 is not critical in this invention and any fastening means which will secure the retaining member 6 in the housing 4 and which is fairly simple to use is acceptable with reference to fig4 which is a top view of the housing 4 there is shown the flange 10 the fastening means opening 9 in phantom the internal threads 17 for accommodating the external threads 18 of the retaining member 6 and the seat 18 for the ball 3 which is located near the bottom edge 15 of the housing 4 further with reference to fig5 which is a top view of the housing 4 wherein there is shown the flange 10 therein is situated in the housing 4 a retaining member 6 wherein there is shown the top 19 of the retaining member 6 a concavity 20 in the top 19 and detachedly fixed in the concavity 20 a grease zerk fitting 21 generally such grease zerk fittings 21 are threaded and screwed into a threaded opening and that is contemplated within the scope of this invention as well as any convenient means of inserting and fastening the grease zerk fitting 21 also shown in this figure are indentions 22 which are indented in the wall of the concavity 20 which indentions 22 are useful for applying a wrench or some other viable means to turn the retaining member 6 in and out of the housing 4 the indentions 22 are not critical to this invention and can be optionally included in the retaining.