Abstract: Protective headgear configured for protection of a portion of a wearer's head, including a resilient outer shell, a layered composite liner including a multiplicity of deformable layers, each layer having a different stiffness than adjacent layers, and wherein a layer has a higher stiffness than that of adjacent layers on either side, and a retention system configured to resist upward/rearward rotation of the headgear with respect to the wearer's head to expose the forehead, due to hydrodynamic or aerodynamic forces.

Abstract: Protective headgear configured for protection of a portion of a wearer's head, including a resilient outer shell, a layered composite liner including a multiplicity of deformable layers, each layer having a different stiffness than adjacent layers, and wherein a layer has a higher stiffness than that of adjacent layers on either side, and a retention system configured to resist upward/rearward rotation of the headgear with respect to the wearer's head to expose the forehead, due to hydrodynamic or aerodynamic forces.

Abstract: A helmet is formed with a rigid outer shell and three energy-absorbing layers made of two types of CONFOR™ ergonomic, open-celled polyurethane foams. The first layer adjacent the rigid outer shell is a CONFOR™ CF-40 yellow foam and the middle layer is a CF-47 green foam, which is of greater stiffness than the outer layer. The inner-most layer is also a CF-40 yellow foam and, therefore, identical to the outer energy-absorbing layer. The three layers are 0.5″ thick. The helmet body is secured to a user's head with straps, affording a helmet design capable of continuously absorbing energy from multiple impacts while retaining the property of returning completely to its original shape. The multiple layering of materials having different stiffnesses results in the reflection of propagating stress waves through the materials, ultimately absorbing larger amounts of energy than the same materials not layered with alternating stiffnesses could absorb.

Abstract: A helmet is formed with a rigid outer shell and three energy-absorbing layers made of two types of CONFOR™ ergonomic, open-celled polyurethane foams. The first layer adjacent the rigid outer shell is a CONFOR™ CF-40 yellow foam and the middle layer is a CF-47 green foam, which is of greater stiffness than the outer layer. The inner-most layer is also a CF-40 yellow foam and, therefore, identical to the outer energy-absorbing layer. The three layers are 0.5″ thick. The helmet body is secured to a user's head with straps, affording a helmet design capable of continuously absorbing energy from multiple impacts while retaining the property of returning completely to its original shape. The multiple layering of materials having different stiffnesses results in the reflection of propagating stress waves through the materials, ultimately absorbing larger amounts of energy than the same materials not layered with alternating stiffnesses could absorb.

Abstract: An erosive fluid jet tool for underwater operation, comprising an erosive fluid jet nozzle connected to a fluid receiver receiving fluid under elevated pressure for providing hydraulic power to the tool, the nozzle providing the working output jet of the tool; and a counterthruster for providing a counterthrusting force for balancing the thrust on the tool produced by the erosive fluid jet, the counterthruster including (a) a counterthrusting fluid jet nozzle connected to the fluid receiver and facing oppositely to the erosive nozzle for providing a counterthrusting jet, and (b) an open ended shroud coaxially surrounding the counterthrusting nozzle, whereby water surrounding the submerged tool is entrained through the shroud for providing additional counterthrusting force during operation of the counterthrusting nozzle, the erosive fluid jet nozzle and the counterthruster being constructed so that in excess of 50% of the hydraulic power provided to the tool is provided to the erosive fluid jet nozzle.

Abstract: Fluid jet apparatus and method for cleaning material from the inside of a tubular conduit utilizing a cleaning head that lies adjacent to one wall of the conduit and includes at least two fluid jet forming means for directing a plurality of high pressure fluid cutting jets in a forward direction and at an acute angle relative to the axis of the head and the conduit so that they are directed toward the opposite wall of the conduit. The cleaning head is rotated around and remains adjacent to the wall of the conduit and is advanced into the conduit as the jets cut away the material whereby the fluid jets create an asymmetric cutting pattern on the surface of the material and the counter thrust of the fluid jets keeps the cleaning head offset relative to the axis of the conduit and against the wall of the conduit to provide passage for removal of the cut material and spent fluid away from the cutting area and out the end of conduit.

Abstract: A drill bit and a method for deep-hole drilling in which the drill bit has mechanical cutting means located on its lower cutting face for cutting a solid surface upon rotation of the bit and a plurality of cavitating liquid jet nozzles spaced around the face of the bit to assist in the drilling action, the nozzles being located so as to discharge a plurality of downwardly directed and concentric liquid jets that cavitate to fracture the surface to be drilled in a series of non-overlapping slots as the bit is rotated.

Abstract: A drill bit and a method for deep-hole drilling in which the drill bit has mechanical cutting means located on its lower cutting face for cutting a solid surface upon rotation of the bit and a plurality of cavitating liquid jet nozzles spaced around the face of the bit to assist in the drilling action, the nozzles being located so as to discharge a plurality of downwardly directed and concentric liquid jets that cavitate to fracture the surface to be drilled in a series of non-overlapping slots as the bit is rotated.