Abstract: An angular plate for connecting channel shaped flanges at the ends of ducts and including first and second legs each having substantially planar top and bottom surfaces and with an inner end portion of the first leg joined to an inner end portion of the second leg so as to establish an angle therebetween. Defined by the inner end portions is an opening for receiving a connector, the first leg has substantially parallel inner and outer edges extending between an outer end portion thereof and its inner end portion and the second leg similarly has substantially parallel inner and outer edges extending between an outer end portion thereof and its inner end portion. The outer end portion of the first leg defines structure projecting extending transversely from at least one of the inner and outer edges of at least one of the first and second legs. The projection engages a side wall portion of the duct's transverse flange to retain the plate in a desired position prior to crimping of the flange.

Abstract: The invention concerns a power supply for an arc welder. A main transformer drives a plurality of secondaries. The invention provides a switching and control system that derives fully rectified power from the secondaries, at an adjustable duty cycle, and applies the power to a welding electrode. One advantage to using a plurality of secondaries is that each supplies part of the total electrode current. Thus, the rectification and duty-cycle control can be accomplished by individual devices (such as SCRs) which are distributed over the secondaries. The total cost of the individual devices can be less than the cost of a single device, of equivalent current capacity, used in a single secondary.

Abstract: In accordance with the present invention, a plasma arc torch contact starting system has a torch head having an electrically conductive plasma exit nozzle at one end and a pilot arc chamber within the torch head immediately adjacent the plasma exit nozzle. An electrode is mounted in the torch head for movement relative to the nozzle. An arc-drawing mechanism is operably connected to but substantially thermally isolated from the electrode and the torch head for biasing the electrode into contact with the nozzle and for displacing the electrode from the nozzle to draw a pilot arc in the pilot arc chamber.

Abstract: A punch and die assembly including a punch having an outer surface conforming generally to a configuration desired for a sheet metal part to be produced and adapted for rectilinear movement in a given direction between retracted and extended positions, the punch having a rear portion with a cross-section of given width and a front portion with a cross-section of predetermined width greater than the given width; and a die body defining a cavity comprising an outer portion defining an opening for receiving the punch and an inner portion communicating with the outer portion. The inner portion has a cross-section with substantially uniformly spaced side walls dimensioned so as to closely accommodate the front portion of the punch and a sheet metal workpiece, and to provide between said rear portion of the punch and the side walls a gap greater than twice the thickness of the workpiece when the punch is in its extended position within the outer portion of said cavity.

Abstract: A die for use with a punch for bending flat metal stock and including a body defining a support surface adapted to support a piece of flat metal stock, a cavity disposed in a path of movement of the punch and intersecting and projecting below the support surface, and a stop surface forming a bottom wall of the cavity and having first and second surface portions; and a mounting retained by the body. A first elongated die bar is supported by the mouting for both translational and pivotal movement on a first axis in the cavity on one side of the path of movement; the first die bar defining upper and lower surfaces having a wedge shaped cross-section. A second elongated die bar also is supported by the mounting for both translational and pivotal movement on a second axis in the cavity on an opposite side of the path of movement; the second die bar defining upper and lower surfaces having a wedge shaped cross-section. This combination eliminates scoring during the bending of flat metal stock.