GB633906A - Improvements in or relating to a method of and apparatus for expanding tubes in tube seats - Google Patents

Abstract

633,906. Tube expanders. BABCOCK & WILCOX, Ltd., and CARLSON, W. B. Aug. 28, 1947, No. 23858. [Class 83 (iv)] In a power-driven tube-expander, the increase in the mandrel driving-power, required when the clearance between the tube 1 and the tube seat 2 is taken up and the seat offers additional resistance, is detected, and initiates means restricting further axial movement of the mandrel to a predetermined distance. A mandrel 3, driven by an electric motor 6 fed through a switch unit 8 is controlled by start, stop, and reverse buttons 19, 20, 21. The electric supply is measured in a wattmeter 9 having an adjustable contact 32 engaged by a pointer 30 to initiate the further mandrel movement control means when the power taken suddenly increases. A delay prevents premature operation by tube defects, scale, &c. A synchronous generator 12 on the motor shaft drives, through a magnetic clutch a motor 14 operating a pointer 39 set against spring bias, when the clutch is free, to adjust the mandrel movement directly, or in selffeeding types the revolutions. The pointer 39 engages a contact 44 to stop or reverse the mandrel drive according to the setting of a switch 15 in a relay unit 16. Operation. Pressing the button 19 rotates the mandrel 3 to expand the tube end 1, and when the tube 1 nips the seat 2 the power increases and wattmeter pointer 30 engages contact 32 to energize the magnetic clutch through relays. The pointer 39 then moves in proportion to the mandrel revolutions or axial travel, until it engages the contact 44 to stop or reverse the drive. The stopped machine is reversed by the button 21 and stopped at any time by the button 20. In a modification, Fig. 4 (not shown), the axial travel of the mandrel 3 is measured directly by an arm engaging the mandrel shaft and operating the generator 12.