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262 I\ THE MARINE REVIEW NN XN Sx TT ke LS — ——— ‘wane PS | — 95-0" LIFT 13129" FOR 10540" LIFT 129" FOR 95=0°LIFT ~ 105-0" LIFT TES: YT by y i iz 4 Y j 16-0" tt if} | ssiulltg ith i “Eg t 20°0'€ rot UF Pais NEW SHIPYARD CRANE nected to two trucks through spur and bevel gearing. The motors are mounted on platforms on top of the main portal. The hoisting drum is driven through suitable spur gear reductions. . Change gears inserted in the hoisting gearing permit the hoisting speed to be increased when handling 5-ton loads and lighter. A double throw jaw clutch controlled by a hand lever is provided for connecting and disconnecting the high and low speed gears. ; The hoisting trolley is carried on four - single-flanged steel wheels. The trolley travel mechanism is a self-contained unit carried on a cast iron bed plate. The winding drum is driven through a double spur gear reduction, the shafting for which is mounted in cap bearings cast integral with the bed plate. The boom is rotated by means of a cast steel pinion meshing with a rack secured to the circular girder at the top of the tower. This pinion is keyed to a ver- tical shaft connected to, the rotating motor. The entire boom is mounted on two equalizing doub!e wheel trucks and two single wheel trucks. Foot brakes are provided on both the hoisting and slewing mechanism. Those on the former will hold or lower the maximum lifting load, The brake on the slewing mechanism has sufficient power to hold the boom against a wind load of 10 pounds per square foot. The hoist and bridge motions are equipped with magnetic brakes. Those on the bridge are fitted with dashpots to pre- vent too quick action in stopping. The electrical equipment is designed for an alternating current of 440 volts. Five motors are provided—two of 37 . 7640" TRAVEL 52-0" Rapius eee: aR 90-0""RaADIUS 5-0" STONS horsepower each for the bridge, one of 37 horsepower for the hoist, one of the same size for slewing, and one of ll horsepower for the cross travel. Each motion is provided with a_ standard drum controller. Special attention was given to the provision of safety devices. All gears are enclosed. ‘Hand railings are pro- vided around all platforms. The lad- ders are of the safety type while a plat- form near the cab level extends around the tower, making the operator’s cab accessible with the boom in any position. A limit on the hoist prevents over- travel. Steel Bending Brakes The steel bending brake shown in the accompanying illustration has been developed by the Dreis & Krump Mfg. Co., Chicago, for bending plates up to % inch in thickness. Bending brakes have been manufactured by this company for a number of years and are used by a number of ship- building companies and navy yards. Machines of various sizes are built to handle sheets and plates from the light- est gage up to % inch in thickness. Steel is used throughout in con- structing these brakes. Steel cast- ings and drop forgings are used for hinges and for other parts where great strain is encountered. The company’s steel power bending brakes are made in a wide variety of sizes and capacities. The machines are self-contained. The motor is out of the way, being placed well under the bottom leaf of the brake. For. driving, a rawhide pinion. on _ the motor engages a gear on the rear shaft, to which two frictton clutches are at- tached. These regulate the rais- ing and lowering of the apron or bending leaf through the direct and reverse gears. A special feature of these machines is the power clamp July, 1917 which is designed to insure a uniform bend when handling heavy plates by flat- tening the buckles before the plate is bent. The heavier brakes, as in the one illustrated, are equipped with this power clamping device which raises and lowers the upper jaw and has “suffi- cient power to flatten buckled plates. No adjustment for plates of different thickness is required as the clamp locks at any point. The adjustment for different thick- nesses of material and for sharp and rounding bends consists of an eccen- tric within the connecting link, the revolving of which increases or de- creases the pressure on the sheet or plate. Set and draw screws provide for moving the upper jaw forward or backward. Part of the upper edge is removable from the apron or bend- ing leaf so that close reverse mem- bers” ¢an be ‘bent. The “apron is slightly underbalanced by the weights so that when the clutch is released, the apron comes down of its own weight. The movement of the apron also is controlled by a brake device by means-of the clutch lever. The lever actuating the friction clutches is’ at the end of the machine near the operator. The angle to which the sheet or plate is to be bent is regulated by this lever or by means of an automatic stop gage which can be set to make a number of bends to the same angle. This gage con- sists of an adjustable collar on the steel gear-cut rack that operates posi- tively in raising the apron. When the apron is lowered to the. extreme point, this clutch disengages itself automatically. Among different shipbuilding firms using these brakes are the Detroit Shipbuilding Co., Manitowoc Ship- building Co., Ames Shipbuilding Co., Union Iron Works, San Francisco, and: the. ‘Lake Torpedo. Boat” Co., Bridgepart, Conn., as well as by vari- ous government navy yards. TELL MOTOR DRIVEM BRAKE 12-FOOT BRAKE FOR-BENDING %-INCH PLATE, SHOWING DRIVE ARRANGEMENT AND POWER CLAMP