TELESCOPIC MAST Russian patent published in 2014 - IPC E21B15/00 

FIELD: machine building.

SUBSTANCE: telescopic mast consists of bottom stationary section, top extending section, telescoping mechanism and top section supporting and locking assy. Beams 13 with support surfaces and converging surfaces with spacing there between decreasing from bottom to top are mounted at telescopic mast bottom section top part 12 in symmetry about vertical axial plane. Beam 4 with support surfaces and lugs 7 is arranged at top section 6 lower part whereto shoes 15 are hinged by pins 16. Strut 8 is arranged at the centre of beam 4 in symmetry with axial plane. Two-arm levers 11, 9 with rollers 14, expansion spring 3, links 1 and pawl 5 are articulated with lugs of said strut with the help of pins 10. Links 1 articulate levers 11, 9 with shoes 15. Pawl 5 is articulated with lever 9 to rest on pin 2 of lever 11 by top or bottom surface. Locking proceeds as follows. Prior to lifting top section, pawl 5 is placed on pin 2 by its lower working surface. At top section lower position, spring 3 and shoes 15 press top arms of levers 11, 9 to strut 8. Shoes stay in maximum down position. At lifting the top section 6 rollers 14 get in contact with converging surfaces to make levers 11, 9 turn shoes 15 via link 1 to position approximating to closing position. Top arms of levers 11, 9 depart to make lower working surface of pawl 5 slide off the pin 2. Under gravity, pawl 5 downs on pin 2 by upper working surface. At said position top section stops to make shoes 15 hang above support surfaces of beam 13. Top section is downed to make pin 2 thrust against closing surface of pawl 5 and inhibit turn of shoes 15 by gravity. Said shoes reach the support surface to turn thereabout and to rest on support surfaces of beam 4 of top section 6. Top arms of levers 11, 9 diverge to make pawl 5 slide off pin 2 and hang on lever 9. To down the bottom section it is to be lifted to extreme top position. Shoes 15 are turned by gravity on pins 16 to pass by support surfaces of bottom section 12.

EFFECT: perfected design.

2 dwg