Abstract: A tactical combat rifle includes a two-part, bolt carrier. The upper part of the bolt carrier rides on rails formed in an upper receiver while the lower part of the bolt carrier, although attached to the upper part and moving with it, engages no supporting surfaces. A piston, driven by combustion gases from a regulatable gas block assembly, strikes the upper bolt carrier in the center of its mass to propel it rearward. The barrel is threaded to a removable barrel extension and secured to the upper receiver. A non-reciprocating charging handle is located far forward and accessible from either side of the upper receiver so the user does not have to lower the rifle from the shoulder or take eyes off the target. Combustion debris is kept away from the lower receiver and bolt so operation is cleaner and cycling rates of fire steadier.

Abstract: A reversible modification to the gas block of a machine gun reduces the rate of fire to the machine gun's design rate for use when a suppressor has been added to the barrel and which suppressor would, without the present modification, elevate the firing rate from the machine gun's design rate. The modification is the use of a stem inserted into the bore of the gas block nozzle to further limit the combustion gas being delivered to the machine gun's operating group. A hole formed in the stem restricts gas flow. The stem seats against the gas block nozzle and is held in place by the cap covering the gas block but may alternatively be held in place in several alternative ways described. Removal of the cap allows the stem to be removed from the gas block when the suppressor has been removed from the machine gun barrel.

Abstract: A magnetic drive apparatus includes first and second magnet carriers carrying first and second permanent magnet arrangements. An intermediate magnet carrier disposed between the first and second magnet carriers carries a third permanent magnet arrangement. The magnet carriers are arranged for rotation relative to each other such that the magnet arrangements produce magnetic interactions that result in power stroke forces causing the magnet carriers to undergo relative reciprocation in first and second stroke directions during power zone portions of the relative rotation. The magnetic interactions impart substantially no power stroke forces during dead zone portions of the relative rotation. The dead zones include magnet carrier relative rotation positions wherein opposing magnetic poles are mutually coaxially aligned but produce a substantially equal balance of push and pull magnetic forces.

Abstract: The present invention is a T-rail that is capable of supporting, in the preferred embodiment, a day and night optical sights, image intensifier and thermal imaging device (scope) and an infrared laser designator. The scope is supported on an upper rail while the designator is supported on an extension that extends perpendicularly away from the upper rail. The T-rail supports these two objects in alignment so that when the T-rail is removed from the weapon and subsequently replaced, the two objects remain in alignment. The T-rail is designed to be mounted to a standard Picatinny rail and comprises a jaw and flange along its bottom to facilitate this mounting. The jaw has a top surface and a bottom surface that matingly engage the top and bottom slope of one side of the Picatinny rail, while the flange has only an upper surface that rests along the top slope of the other side of the rail.

Abstract: The present invention is a handgun having a polymeric frame with metallic rails that are inserted within the frame after the frame has been formed by a molding process. The rails are inserted into recesses formed in a channel within the frame, before the frame has completely cooled and contracted. The rails comprise a pair of front rails and a pair of rear rails. The rear pair of rails are positioned within rear recesses and held in place by the sear block. The front pair of rails are positioned within front recesses and held in place by a plurality of metallic parts. The parts include a horseshoe, an unlock block, and a spreader block that are positioned between and matingly engage the front rails, thus securing them within their respective recesses.

Abstract: A portfolio or presentation folder having one or more expandable pockets which can be manufactured from a single piece of appropriate sheet material is disclosed. Each pocket is formed in a portion of the cover of the portfolio and by a pair of flaps, each flap being integral with the main body of each of the portfolio covers. One flap is positioned at a side of the portfolio cover and the other flap is positioned along a bottom edge of the portfolio cover. Thereafter, the side and bottom flaps are folded in such a manner that the side flap is sandwiched between sections formed in the bottom flap and an expandable pocket is formed without the use of adhesives or other fastening means.

Abstract: A centrifugal submersible pump has wear resistant features to resist erosion due to sand laden fluid from a well. The pump has diffusers and impellers located within a housing. Wear resistant inserts are secured to the diffusers and impellers. The inserts include inserts with cylindrical surfaces for radial support and sealing, and inserts with flat transverse surfaces for thrust. The inserts are preferably formed of tungsten carbide and are harder than the material of the impellers and the diffusers.

Abstract: A current limiting fuse is disclosed in which a main fuse element is wound at a given pitch around a fuse spider or mandrel. An auxiliary fuse element for assisting in low current high voltage current limiting operation is wound at generally the same pitch but in a disposition of non-electrical contact on the same fuse spider or mandrel. At the ends of the auxiliary elements, sheaths of flexible glass material of known thickness and dielectric characteristics are disposed for being wound around a predetermined notch in the fuse element for greatly enhancing the flashover or arc transfer characteristic between the main fuse element and the auxiliary fuse element during a fusing operation.

Abstract: An electrical current limiting fuse having longitudinally spaced support members for fuse elements. The support members comprise a central portion having radial arms supported thereon. Coiled fuse elements are disposed between complementary radial arms of the longitudinally spaced support members. The fuse elements are not coiled around each support member as a whole to completely peripherally encompass it but merely are held at one position on the periphery.