Abstract: An active temperature controlled container is configured to be portable so as to safely transport temperature sensitive and perishable goods (such as biological material): within a vessel that is thermally coupled to a thermoelectric assembly disposed within the container, where the thermoelectric assembly is powered by a battery. The battery is secured within a compartment in an outer portion of the housing of the container in a way that the battery may be removed to be recharged, inspected, swapped out for another battery or power source, or the like.

Abstract: An absorption subcooler comprises a first heat exchanger operable to receive refrigerant from a compressor of a refrigeration system and apply a first cooling stage to the refrigerant. The absorption subcooler is further operable to discharge the refrigerant to a gas cooler operable to apply a second cooling stage to the refrigerant.

Abstract: Generally, apparatuses, systems, and methods are described to vent refrigerant vapor from the refrigerant pump line using a vent line, such as during priming of the pump and/or during a startup of the compressor, directed to a relatively reduced volute casing mass of the refrigerant pump, and/or directed to returning refrigerant to an economizer or chiller component other than the condenser.

Abstract: Embodiments of the present disclosure relate to a heating, ventilation, air conditioning, and refrigeration (HVAC&R) system that includes a refrigerant loop, a compressor disposed along the refrigerant loop and configured to circulate refrigerant through the refrigerant loop, and an evaporator disposed along the refrigerant loop and configured to place the refrigerant in thermal communication with a cooling fluid, where the refrigerant surrounds a tube bundle disposed in the evaporator, the tube bundle is configured to flow the cooling fluid, and the evaporator has a height based at least on a target height of a liquid level of refrigerant in the evaporator, the evaporator includes a discharge configured to direct the vapor refrigerant from the evaporator to an inlet of the compressor, and an interface between the discharge and the inlet is without a bend.

Abstract: Methods, devices, and systems for frost management of an evaporator are described herein. One device includes a memory, and a processor configured to execute executable instructions stored in the memory to receive operating information of a heat pump, determine a first set point of at least one of a number of components of the heat pump and a first operating temperature, receive a second operating temperature of the evaporator that is positively offset from the first operating temperature of the evaporator, determine a second set point of at least one of the number of components of the heat pump based on the second operating temperature, and modify a set point of at least one of the number of components of the heat pump to the second set point such that a heating mode of the heat pump is enabled for a heating interval length of the heat pump.

Abstract: Provided is a refrigeration cycle apparatus including: a refrigeration cycle configured to circulate refrigerant; a heat exchanger unit configured to accommodate at least a heat exchanger of the refrigeration cycle; and a controller configured to control the heat exchanger unit, in which: the heat exchanger unit includes: an air-blowing fan; and a refrigerant detection unit configured to detect a concentration of leaked refrigerant and to output a detection signal to the controller; and the controller is configured to operate the air-blowing fan when detecting leakage of the refrigerant, and to stop the air-blowing fan triggered by becoming positive from negative of a temporal change of the concentration of the leaked refrigerant.

Abstract: A control system controls the output capacity of a compressor to avoid surge conditions in the compressor. The control system determines a capacity control output for the compressor and then modifies the capacity control output in view of any output limiters or overrides as determined by system operating parameters and to maintain a minimum frequency of operation for the compressor.

Abstract: In various implementations, a request for operation of an air conditioner may be received. The air conditioner may include a cooling mode and/or a dehumidifying mode. In some implementations, a compressor speed for a compressor of the air conditioner may be determined, and which mode(s) of the air conditioner to allow may be determined based at least partially on the determined compressor speed.

Abstract: An evaporator includes a refrigerant conduit; and front and rear plates sandwiching the refrigerant conduit, each of the front and rear plates including: a plurality of ice forming columns; a set of first protrusions and a set of second protrusions defined therein, each first protrusion on the front plate and a corresponding first protrusion on the rear plate defining a respective active cavity and each second protrusion on the front plate and a corresponding second protrusion on the rear plate defining a respective passive cavity, the refrigerant conduit extending through each of the active cavities but not any of the passive cavities; and inner flat portions of the front plate and the rear plate facing each other to define respective spaced portions, wherein the active cavities and passive cavities are interspersed and separated by respective inner flat portions so as to define a plurality of ice forming sites.

Abstract: A refrigerator includes a main body, a door rotatably coupled to the main body, a first ice making compartment configured to generate and store ice and provided in the main body, a second ice making compartment configured to crush ice and provided in the door, and a transfer device provided to transfer the ice in the first ice making compartment to the second ice making compartment. Therefore, a structure of an ice bucket storing ice is simplified, and an ice making system is easily constructed.

Abstract: Provided is an apparatus for sensing and removing dew on a refrigerator. The apparatus may include a heater disposed at a refrigerator body or inside a surface of a door, and a sensor disposed in close proximity to the heater. The sensor may be configured to sense dew formed on a prescribed surface at the refrigerator body or the door. The sensor may be disposed physically separate from the prescribed surface to sense formation of dew on the prescribed surface. The heater is controlled to generate heat that removes the sensed dew on the prescribed surface based on a signal from the sensor.

Abstract: The present invention provides a refrigerator comprising a cabinet having a storage chamber; an inner case forming the exterior of the storage chamber; a first door pivotally provided to the cabinet and opening and closing one side of the storage chamber; a second door having a pillar rotated so as to come into contact with the first door, pivotally provided to the cabinet, and opening and closing the other side of the storage chamber; and a driving member provided at a lower end of the second door so as to move together with the second door, and operating the pillar so as to fold or unfold the pillar, wherein the pillar has a first catching protrusion and a second catching protrusion, which are selectively caught by the driving member.

Abstract: A storage bin assembly for a refrigerator is provided. The storage bin assembly includes a base portion having opposed outer end sidewalls upwardly extending from the base portion. A flap is pivotally coupled to the opposed outer end sidewalls where the flap is configured to rotate between a closed position and an open position where the flap is positioned beneath the base portion. A top cover is coupled to a receiving slot portion of the opposing outer end sidewalls where a first magnetic member is positioned in a holding member proximate the top cover. A second magnetic member positioned in a receiving member of the flap that selectively engages the first magnetic member to define a magnetic connection.

Abstract: A refrigerator is provided including a main body having a storage chamber, a door coupled with the front surface of the main body, to open or close the storage chamber, and a case having a rear surface facing the rear surface of the door the front part of the case having an opening. A door guide is in the case. A sliding apparatus enables the door guide to slide to be inserted into or pulled out of the case through the opening and includes a guide rail at a bottom of the door guide, an inclined guide portion in the case to guide the guide rail, a fixing rib at the rear end of the guide portion including a streamlined shape at the front end of the fixing rib and a supporting rib in the door guide supported by the fixing rib to prevent the door guide from moving.

Abstract: Disclosed herein is a refrigerator. The refrigerator comprising, a housing comprising a storage compartment, a door configured to open or close the storage compartment, a rotating bar provided at the door to be rotatable and configured to be located at a first position when the door opens the storage compartment and to be located at a second position lower than the first position when the door closes the storage compartment, and a guide part provided at the housing and configured to guide rotating of the rotating bar.

Abstract: A refrigerator may include a cabinet forming a storage compartment; a rear panel forming a rear wall of the storage compartment and having a cooling air outlet hole which discharges cooling air toward the storage compartment; a fan housing coupled to the rear panel and in which a fan configured to circulate cooling air is installed; an outlet port which is formed at the fan housing and discharges cooling air supplied by driving of the fan; and a drawer provided capable of being withdrawn forward from an inside of the storage compartment, wherein the drawer includes: a drawer body forming a storage space; and a cooling air duct provided above the drawer body and having a cooling air path in communication with the outlet port.

Abstract: A cooling apparatus is provided in which items to be cooled may be vertically stacked on each other in a state in which the items to be cooled are laid out or laid on their sides. When the items to be cooled are vertically stacked in the cooling apparatus, a problem in that an upper space of the cooling apparatus is not utilized may be solved to efficiently utilize an inside of a refrigerator or a back surface of a door. Also, a problem in that capacity within the refrigerator is reduced when the items to be cooled are horizontally received may be solved.

Abstract: This method comprises: forming an expanded intermediate recirculation stream (170) from a liquid (112, 128) obtained during an upstream cooling and/or intermediate cooling step, upstream from the downstream cooling step; circulating the intermediate recirculation stream (170) at least in an upstream heat exchanger (42) to cool an upstream stream of cracked gas (102); reintroducing the reheated intermediate recirculation stream (170) in a raw cracked gas (20) upstream from at least one compressor (36, 38) of a cooling and compression stage (24). The upstream, intermediate and downstream cooling steps is carried out without a heat exchanger respectively of an upstream stream of cracked gas (102), an intermediate stream of cracked gas (114) and a downstream stream of cracked gas (140) with an external refrigeration cycle.

Abstract: A method and device used to variably obtain a compressed-gas product by means low-temperature separation of air in a distillation column system. In a first operating mode, a first amount of first compressed-gas product is obtained, and, in a second operating mode, a second, smaller amount is obtained. In the first operating mode, a first amount of air is compressed in the main air compressor, and in the second operating mode, a second, larger amount is compressed in the main air compressor.

Abstract: A multiple pass, parallel flow downcomer tray for a mass transfer column and method for liquid-vapor contacting in a mass transfer column is provided. The multiple pass, parallel flow downcomer tray has at least four mass transfer decks configured to provide contact between an ascending vapor passing upward through apertures on the tray surface and a traversing liquid on the tray surface. The tray further includes a central downcomers disposed near a central axis of the tray and two or more peripheral downcomers disposed near the edge of the tray and spaced apart from the central axis, wherein at least two of the four mass transfer decks are configured to discharge the traversing liquid into the peripheral downcomers and two of the four mass transfer decks are configured to discharge the traversing liquid into the central downcomer.

Abstract: A method for separating components from a fluid is disclosed. A cooling element is provided and is disposed in contact with a distal side of one or more thermally-conductive surfaces. One or more resistive heating elements are provided and are disposed in contact with or embedded in a proximal side of the one or more thermally-conductive surfaces. A fluid comprising one or more secondary components is provided. The fluid is passed across the one or more thermally conductive surfaces, the one or more secondary components freezing, crystallizing, desublimating, depositing, condensing, or combinations thereof, out of the fluid. The one or more resistive heating elements engage such that the one or more solid secondary components detach and pass out the solids outlet. The one or more resistive heating elements disengage, restarting production of the one or more solid secondary components.

Abstract: A method of using a vacuum chamber to assist in detecting moisture on an instrument, removing moisture from the instrument, and confirming dryness of the instrument is disclosed. The method may include the steps of opening a vacuum chamber; placing an instrument into the chamber, closing the chamber, withdrawing a first volume of air from the chamber; changing a volume of liquid water into vapor, introducing a second volume of air into the chamber, withdrawing the second volume of air from the chamber, changing a second volume of liquid water into vapor, introducing a third volume of air into the chamber, opening the chamber, and removing the instrument from the chamber in a dry state.

Abstract: A cosmetic sponge drying and storage container has a plurality of components, including at least a first component and a second component, the first component being moveable with respect to the second component to position the container in at least an open condition and a closed condition. At least one of the first component or said second component is perforated with perforations. A cosmetic sponge may be placed within the container when in the open condition and the perforations provide at least 10% ventilation when the container is in the closed condition. Preferably, both the first and second components are perforated to provide for cross-ventilation. In addition, a base may be provided to support the first and second components, and most preferably the base may be perforated.

Abstract: Flue gas entry into the tunnel(s) of a furnace is controlled by varying the flow conductivity or size of the individual or groups of openings through the entry ports. The openings can be provided either as gaps between adjacent blocks, or through bores of varying diameter, or as inserts having orifices of varying diameter and a profile matching the ports in which they are placed. Matching the flow conductivity (or cross-sectional flow area) and pressure drop through the individual ports to the desired mass flow, the flue gas flow can be distributed evenly, or as otherwise desired, into different ports, intervals, and/or regions of the tunnel.

Abstract: A system and method for transferring molten metal from a vessel and into one or more of a ladle, ingot mold, launder, feed die cast machine or other structure is disclosed. The system includes at least a vessel for containing molten metal, an overflow (or dividing) wall, and a device or structure, such as a molten metal pump, for generating a stream of molten metal. The dividing wall divides the vessel into a first chamber and a second chamber, wherein part of the second chamber has a height H2. The device for generating a stream of molten metal, which is preferably a molten metal pump, is preferably positioned in the first chamber. When the device operates, it generates a stream of molten metal from the first chamber and into the second chamber. When the level of molten metal in the second chamber exceeds H2, molten metal flows out of the vessel and into another structure, such as into one or more ladles and/or one or more launders.

Abstract: A support ring for supporting a semiconductor wafer in a boat of a vertical furnace used in processing of the semiconductor wafer includes a semicircular segment. The semicircular segment has an upper surface, a lower surface opposite the upper surface, a radial inner wall defining an inner radius, and a radial outer wall defining an outer radius. The support ring further includes protrusions in the upper surface of the semicircular segment. The protrusions extend above the upper surface.

Abstract: One embodiment is directed to an oven for heating fibers. The oven comprises a supply structure disposed within the oven between first and second ends of the oven. The supply structure comprises a plurality of plenums. The plenums are in fluid communication with a heating system. Each of the plenums comprises a pair of side walls, a bottom wall, and a top wall. Each of the plenums is configured so that first openings are formed in the respective side walls of that plenum. At least one plenum is configured so that one or more second openings are formed in at least one of the top wall or the bottom wall of at least one plenum. The at least one plenum is configured to supply heated gas from the heating system into the chamber from the first openings and said one or more second openings of the plenum.

Abstract: A pressing arrangement for treatment of articles by hot pressing includes a pressure vessel including a furnace chamber and a furnace to hold the articles. A fan circulates a pressure medium within the furnace chamber, and enhances an inner convection loop at a load compartment. The inner convection loop pressure medium has an upward flow through the load compartment, and a downward flow along a peripheral portion of the furnace chamber. A flow generator generates a flow of pressure medium into the load compartment downstream the fan to enhance the inner convection loop. The flow is generated by transporting the pressure medium upwards from a space below a bottom insulating portion and above a bottom end portion, and by injecting the pressure medium into the load compartment downstream the fan to enhance the inner convection loop.

Abstract: Employing furnace combustion gases for both thermochemical regeneration and heating of regenerators to preheat oxidant for the furnace provides synergistic efficiencies and other advantages.

Abstract: A refrigerant heat exchanger is provided and includes: a hollow container having a cylindrical shape; a plate stack disposed on an inner lower side of the hollow container, including plates each having a front side and a back side with a plurality of concavo-convex portions formed thereon which are stacked to form a first heat exchange flow passage through which a first refrigerant flows and a second heat exchange flow passage through which a second refrigerant flows; a supply pipe disposed in an interior space of the hollow container above the plate stack and configured to supply the first refrigerant to the plate stack; and a discharge pipe configured to exchange heat between the first refrigerant supplied from the supply pipe and the second refrigerant flowing through the plate stack and to discharge the first refrigerant.

Abstract: A heat exchanger assembly includes a shell, a first inlet duct, and a second inlet duct. The shell has a core that is provided with a plurality of first fluid channels and a plurality of second fluid channels. The first inlet duct has a plurality of first feed channels extending towards and fluidly connected to the plurality of first fluid channels. The second inlet duct has a plurality of second feed channels extending towards and fluidly connected to the plurality of second fluid channels. The plurality of first feed channels are interwoven with the plurality of second feed channels proximate an intersection region between the first inlet duct and the second inlet duct.

Abstract: A heat exchanger and a method for manufacturing a heat exchanger, the heat exchanger comprising: a first plurality of layers, each of the first plurality of layers including: a corrugated sheet comprising a series of regular corrugations across its width for flow of liquid therethrough, the series of corrugations having a predetermined period; and a de-congealing channel for flow of liquid across the width of the corrugated sheet in parallel with the corrugations, the de-congealing channel formed at least in part by two adjacent corrugations, that are separated by greater than the predetermined period.

Abstract: A conformal thermal ground plane is disclosed according to some embodiments along with a method of manufacturing a conformal thermal ground plane according to other embodiments. The method may include forming a first planar containment layer into a first non-planar containment layer having a first non-planar shape; forming a second planar containment layer into a second non-planar containment layer having a second non-planar shape; disposing a liquid cavity and a vapor cavity between the first non-planar containment layer and the second non-planar containment layer; sealing at least a portion of the first non-planar containment layer and at least a portion of the second non-planar containment layer; and charging at least the liquid cavity with a working fluid.

Abstract: A flexible heat sink with a flexible base having a first side configured to engage a heat generating component, and a second side opposite the first side. A plurality of groups of fins extend from the second side of the base. The groups of fins are positioned in an array and spaced apart lengthwise and width wise across the base to enable the heat sink to flex lengthwise and width wise. The heat sink is able to flex lengthwise and width wise between the groups of fins. The fins and groups of fins also may provide some flex. The fins may define triangular, rectangular, or u-shaped channels to enable air flow through the heat sink.

Abstract: An airtight penetration structure for heat dissipation device includes a first plate member, a second plate member, and a plurality of hollow shaft members. The first and the second plate member are closed to each other to together define a closed chamber between them. The hollow shaft members are respectively provided at two free ends with a first and a second flange. The hollow shaft members are correspondingly extended through fastening holes provided on the first and the second plate member with the first and the second flanges attached to and flush with outer surfaces of the first and the second plate member to seal around the fastening holes, so that the closed chamber between the first and the second plate member is in an airtight state.

Abstract: The present application discloses two-phase cooling devices that may include at least three substrates: a metal with a wicking structure, an intermediate substrate and a backplane. A fluid may be contained within the wicking structure and vapor cavity for transporting thermal energy from one region of the thermal ground plane to another region of the thermal ground plane, wherein the fluid may be driven by capillary forces within the wicking structure. The intermediate substrate may form narrow channels within the wicking structure, providing high capillary forces to support large pressure differences between the liquid and vapor phases, while minimizing viscous losses of the liquid flowing in the wicking structure.

Abstract: A heat transfer device includes a heat pipe in which working fluid is enclosed, a heat receiving plate provided on one end side of the heat pipe and a heat radiating fin provided on the other end side of the heat pipe, a first wick and a second wick that transfer working fluid provided on an inner wall surface of the heat pipe, a bent section bent between the one end side and the other end side, and a boundary section between the first wick and the second wick disposed in a lower part in the gravity direction of the bent section of the heat pipe or the heat transfer device. The heat transfer device can improve heat transfer characteristics with a simple configuration.

Abstract: The present disclosure provides pumped thermal energy storage systems that can be used to store electrical energy. A pumped thermal energy storage system of the present disclosure can store energy by operating as a heat pump or refrigerator, whereby net work input can be used to transfer heat from the cold side to the hot side. A working fluid of the system is capable of efficient heat exchange with heat storage fluids on a hot side of the system and on a cold side of the system. The system can extract energy by operating as a heat engine transferring heat from the hot side to the cold side, which can result in net work output. Systems of the present disclosure can employ solar heating for improved storage efficiency.

Abstract: The present invention is a cross-flow evaporator adapted to generate vapor from the heat of the exhaust gases from an internal combustion engine. The evaporator is constituted, among other elements, by two plates spaced from one another which contain chambers. The heat exchange tubes alternately communicate the chambers of both plates, establishing a specific path for the fluid intended to change phase. The tubes extending between the chambers of the two plates are arranged transverse to the flow of the hot gas. This evaporator is suitable for heat recovery systems using a Rankine cycle, making use of the heat from the exhaust gases. The invention is characterized by a special configuration of the chambers by means of caps that allow the evacuation-of the gases generated during a brazing welding in the manufacturing process.

Abstract: An assembly for liquid cooling is provided herein. The assembly 8 includes a thermal member, a support member, and a gasket. The thermal member includes an array of cooling pins formed of a thermally conductive material to extend from the thermal member. The support member includes an inlet channel and an outlet channel. The inlet channel to provide a fluid to the array of cooling pins. The outlet channel to receive the fluid from the array of cooling pins. The gasket between the thermal member and the support member to form a cooling channel with a fluid tight seal therebetween.

Abstract: A plate and frame style heat exchanger is disclosed herein the heat exchanger is formed by a plurality of heat exchange plates and frame members that are alternatingly stacked together to form fluid channel members. The frame members are formed by lengths of material that are formed or bent into the desired configuration for providing a first fluid tight seal around the periphery of the plates and a second fluid tight seal around respective fluid openings formed in the heat exchanger plates in order to achieve the desired flow configuration through the heat exchanger. In some embodiments the frame members are made up of two mating frame portions that join together in a self-aligning and self-fixturing relationship to facilitate assembly.

Abstract: The invention concerns an attachment device (3) for a heat exchanger (2) comprising a core (23) for exchanging heat between a first fluid and a second fluid, said core (23) being provided with collectors (21) for the first fluid, said exchanger (2) comprising a cylinder (25), said cylinder (25) and one of said collectors (21) allowing the passage of said first fluid from one to the other, said attachment device (3) comprising a body, which is set up in order to close said cylinder (25), and an extension which allows the core (23) to be secured to a holder (4). The invention also concerns a cylinder (25) which comprises such an attachment device (3), a heat exchanger (2) which comprises such a cylinder (25) and a heat exchanging module which comprises such a heat exchanger (2).

Abstract: Heat transfer between a fluid-bearing flexible tube and a heat-conducting surface is improved by fixing a flexible heat-conducting sheath to the flexible tube and by compressive fixing that distorts the tube and deforms the sheath and/or the surface. The tube can be made of cross-linked polythene (PEX). The sheath can be spirally wound high-purity aluminum wire. The sheath enables efficient heat transfer between the outer surface of the tube and the heat-conducting surface. Applications include radiant heating and cooling. Tube layout can be customized and variable tube spacing is possible, for example by using a castellated layer to support the tube.

Abstract: A turbulence member is made of a flat plate member configured to be inserted into a heat-transfer tube having a substantially elliptical cross-sectional shape. The flat plate member is a generate turbulence in a fluid flowing inside the heat-transfer tube by a plurality of projected pieces projected on both front and back surfaces. A rotation preventing piece configured to prevent rotation of the flat plate member inside the heat-transfer tube is provided in at least one of both side edges along the flow passage direction in the flat plate member. The rotation preventing piece is provided at a predetermined angle to the flat plate member so that a forefront comes into contact with a tube wall inner circumferential surface of the heat-transfer tube. A space through which the fluid can circulate is formed between the rotation preventing piece and the tube wall inner circumferential surface.

Abstract: A heat exchanger includes a heat transfer tube and a baffle. The baffle includes a main body portion, a first protruding portion, a second protruding portion, a first wall, and a second wall. The first protruding portion protrudes from the main body portion into a first space and the second protruding portion protrudes into a second space. The first wall includes a first protruding wall and a second protruding wall. The second wall includes a third protruding wall and a fourth protruding wall. The first protruding wall and the third protruding wall protrude into the first space and the second protruding wall and the fourth protruding wall protrude into the second space.

Abstract: A dehumidifier drainage system includes a primary drain pan and a secondary drain pan. The primary drain pan is disposed at least partially below an evaporator. The primary drain pan includes one or more raised ribs that are configured to at least partially block air flowing across the primary drain pan as the air flows into the evaporator. The secondary drain pan is disposed at least partially between the evaporator and the primary drain pan. The secondary drain pan includes one or more downspouts. Each downspout is configured to funnel water condensed from the evaporator into an area of the primary drain pan that is at least partially surrounded by one of the raised ribs.

Abstract: A bolt for a bolt-action firearm in one embodiment is movably disposed in a receiver between forward closed breech and rearward open breech axial positions. The bolt includes an operating handle and plurality of bolt lugs arranged to selectively engage locking lugs in the firearm. The bolt is rotatable between locked and unlocked breech positions when in the closed breech position. The bolt body has a dimensionally reduced middle section with unique configuration adapted to allow the bolt to rotate when closed without interference from the magazine feed lips. Using this design, the bolt may include three bolt lugs in one embodiment for secure lockup and minimal angular rotation between the locked and unlocked breech positions. The bolt is usable with both single and double stack box type magazines with one of the bolt lugs operating to reliably strip cartridges from either type magazine.

Abstract: A semi-automatic or automatic rifle comprising a barrel attached to and upper receiver and including a compressible bolt carrier extension system. The compressible bolt carrier extension system includes a bolt carrier, an extension spring, two pins, and a reciprocation bolt carrier extension piece. As a whole, the compressible bolt carrier extension system makes possible the use of elongated upper and lower receivers to be used for chambering long-action or other center fire cartridges for use with AR rifles such as the M-16, and M4 etc., eliminating the need for any buffer or buffer tubes other than those commercially available. A further advantage of the compressible bolt carrier extension system is the reduction of felt recoil as the system fully loads during the recoil stroke as it pushes against the buffer absorbing additional recoil energy. The system can be incorporated into firearms using a variety of cartridges.

Abstract: A firearm includes a bolt mechanism with a bolt configured to receive a firing pin assembly and a bolt head assembly. The bolt head assembly includes a pivoting bolt head and an extractor. The extractor is positioned relative to the bolt such that substantially all forces applied by the extractor to the bolt mechanism are reacted within the bolt head assembly. A biasing member or element can urge a claw portion of extractor towards a distal end of the bolt head.

Abstract: The present invention provides matched upper and lower firearm receivers and method of manufacturing the same. An upper receiver has a forward lug and a rear lug. A lower receiver has forward ears and rear sidewalls that form a pocket. When the upper and lower receivers are positioned together, the forward lug fits between the lower receiver ears and the rear lug fits into the pocket between the sidewalls. Forward openings are formed in axial alignment through the ears and forward lug. Rear openings are formed in axial alignment through the rear sidewalls and the rear lug. Reinforcement sleeves are fitted into the forward openings of the ears and forward lug and into the rear openings of the sidewalls and rear lug.