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Dock Crane--Boring Mill-- Submarine Signaling Device--Thread : Cutting Tools -- Steel for Chisels -- Open-Side Crank Planer Saginaw, Mich., recently installed two electric rotating cranes mounted on portal piers, one of which is shown in the accompanying illustra- 1 HE Saginaw Shipbuilding Co., tion. These. cranes were furnished by the Brown Hoisting Machinery Co., Cleveland. These cranes travel on tracks spaced 18 feet between centers. They span a railroad track and are high enough to allow freight trains to pass under the portal. The rotating and hoisting -mechanism is mounted on the top of the portal. This mechanism also car- ries the operator's cabin where one operator controls all movements of the crane, including traveling along ~ the track, hoisting and lowering of the boom, rotating in a complete circle, as well as hoisting and lowering the load. . An §82-horsepower induction type motor is used for performing all crane functions. The controller is of the reversing drum type. The elec- tric current is 440-volt, 3-phase, 60- Current for operating the crane is taken from' a conductor system along the crane runway. The crane is fitted with collector rings between the revolving superstructure and the cycle. portal pier to allow continuous rota- tion. The hoisting mechanism consists of two hoisting drums, one operating the main hoist, which has a capacity of 15 tons on a 3-part line, the other drum operating an auxiliary hoist of 5-ton capacity on a single part of line. All amovemients of the . crane. are operated through the medium of bal- anced-type friction clutches. For hoisting and lowering the boom, a spur gear driven! mechanism is used. The boom may be hoisted or lowered with a 4-ton load on the hook. Each crane is equipped with a boom 100 feet jong and the radius may - be varied from 100 feet maximum to 40 feet minimum. The motions of hoisting, traveling ELECTRIC ROTATING CRANE MOUNTED ON PORTAL PIERS--ONE OF TWO RECEN AT THE SAGINAW SHIPBUILDING CO., SAGINAW, MICH. TLY INSTALLED 260 ' double and rotating can be performed simul- taneously and at the following speeds: Hoisting 15-ton load on main hoist, feet per TR UUTE aos aoc ieas oa oe ea eho eae wee bo en 30 Hoisting 5-ton load on auxiliary hoist, feet per e Minlte: ee ee eee ies oe eee ie 100 Rotating crane at full "speed, revolutions per PUA LO iaeis cre capi vecierpimieiaes sicah aoe) alien el wre ratetey( oust \, Crane travel on straight track, feet per minute 300 The entire machine is mounted on four 2-wheel equalizing trucks. These trucks are connected to the portal pier legs by means of pins which allow the trucks to equalize on uneven tracks. The wheels have chilled treads with flanges. The crane is pro- vided with ladders and hand rails, so it is easy of access to the revolving superstructure. The crane is used for placing plates, machinery, etc., in ship construction, and, on account of its height and great reach, the entire ship 'can be covered. ----s Side-Head Boring Mill Boring mills are, without a doubt, among the most useful tools to be found in machine shops devoted to marine work as they can. handle a large variety of turned pieces economically. The machine shown in the accompanying il- lustration is a side-head boring mill, developed by the Pratt & Whitney Co., Hartford, Conn., which embodies sev- eral novel features. It is equipped with a turret for holding five tools and-a side head particularly adapted for peripheral turning operations. The bed and column of the mactine are cast together. The left-hand housing has a flat bearing while the right-hand housing has a 3-track bearing with a long, narrow guide for the cross ail and side head. The table and chuck are an integra! unit, mounted directly on the vertical spindle. The chucking arrangement is of ihe 3-jaw type which can be operated iu- dependently or universally. In cases where it is advantageous to strap the work directly to the table, the chuck jaws are readily removed. The chuck pinions are alloy steel, heat treated and hardened to protect them from uadue wear. Each pinion runs in two bear- ings, one on either side. The spindle bearings are made amoly large to insure long wear while a taper bearing is provided to take up vertical thrust. The spindle bearing surfaces are finished by grinding followed by lapping. Power is conveyed for rotating the table through the medium of bevel | :