of latch 64 in one of the slots 44 within one tenth of one second and the mast assembly 20 will only drop a couple of inches before all of the telescoping members come to rest in the event that first hoisting cable 36 were to fail this is assured by the cabling arrangement which slaves the second through the fourth telescoping members to the stationary member and the position of the first telescoping member the arrangement of safety latch 50 and its engagement with first hoisting cable 36 holds the safety latch assembly in the cocked position it has been found in practice that oftentimes the operator when he lowers the mast to its transport position will relieve the tension on first hoisting cable 36 in which case latch 64 will engage in a slot 44 in the first telescoping member 24 however as soon as the operator engages the winch to elevate the mast 20 the tension is restored and the safety latch assembly 50 will be repositioned into its cocked position and clear of slots 44 and first telescoping member 24 in this manner safety latching mechanism is provided for the mast which is automatic in operation it requires no operator intervention and does not require any pins or manual latches to be engaged it will work at all heights and it does not require that the mast be.