An optical active fiber is configured with an asymmetrically-shaped core having at least one long axis and a shortest axis which extends transversely to the long axis. The outmost cladding of the active fiber is configured with a marking indicating the orientation of the short axis. The marking allows for bending the fiber so that the shortest axis extends along and lies in the plane of the bend thereby minimizing distortion of a mode which is guided by the asymmetrically-shaped core as light propagates along the bend.

Implementations and examples of fiber lasers based on fiber laser cavity designs that produce self-similar pulses (“similaritons”) to achieve a pulse spectral bandwidth greater than a gain spectral bandwidth based on a spectral broadening fiber segment and a spectral filter to ensure the proper similariton conditions.

A multi-color harmonic synthesized laser system for laser processing and a laser processing method using multi-color harmonic synthesized laser are disclosed. The multi-color harmonic synthesized laser system includes a laser source for providing a single laser wave, a converter for converting the single laser wave into a plurality of harmonic waves with different frequencies, and a modulating unit for modulating amplitudes and relative phases of the harmonic waves to form a plurality of modulated harmonic waves, so as to synthesize the modulated harmonic waves as a single synthesized laser wave, wherein the single synthesized laser wave is focused on an object to perform a laser processing. The converter includes a plurality of non-linear crystals for converting the single laser wave into a fundamental harmonic wave and a plurality of multi-frequency harmonic waves. The harmonic waves are coherent and collinear, and the phases of the harmonic waves are related to one another.

A microlaser system includes an optical source, a microlaser, an actuator switch, and a photovoltaic power source. The microlaser, which includes a control element, is optically pumped by at least a portion of light emitted by the optical source. The actuator switch is configured to be activated by a triggering event. Furthermore, the photovoltaic power source is coupled in a series connection with the actuator switch and the control element, the series connection configured to connect the photovoltaic power source to the control element of the microlaser when the actuator switch is activated by the triggering event.

The existing diodes in an LED or laser diode package are used to measure the junction temperature of the LED or laser diode. The light or laser emissions of a diode are switched off by removing the operational drive current applied to the diode package. A reference current, which can be lower the operational drive current, is applied to the diode package. The resulting forward voltage of the diode is measured using a voltage measurement circuit. Using the inherent current-voltage-temperature relationship of the diode, the actual junction temperature of the diode can be determined. The resulting forward voltage can be used in a feedback loop to provide temperature regulation of the diode package, with or without determining the actual junction temperature. The measured forward voltage of a photodiode or the emissions diode in a diode package can be used to determine the junction temperature of the emissions diode.

The laser mount arrangement can have a laser bar and a driver positioned adjacent to one another and secured against a connection face of a heat sink base. The heat sink base is connected to and forms a first electrical connection between the laser bar and the driver. A second electrical connection is also provided between the laser bar and the driver opposite the heat sink base, which can be in the form of a flexible metal sheet with a narrow upward fold. This arrangement can provide a low inductance path for the current.

A conduction cooled high power semiconductor laser and a method for fabricating the same are provided. The conduction cooled high power semiconductor laser comprises a heat sink (2) and one or more semiconductor laser units (1). The semiconductor laser unit consists of a laser chip (3), a substrate (4) bonded to the laser chip for heat dissipation and electrical connection, and an insulation plate (5) soldered to the substrate for insulation and heat dissipation. The semiconductor laser unit is soldered on the heat sink with the insulation plate therebetween. The semiconductor laser unit may be tested, aged, and screened in advance, and thereby the yield of the lasers can be improved and the manufacturing costs can be reduced. The laser has desirable heat dissipation performance, high reliability, and is applicable to high temperature and other complex and volatile environments.

Implementing a layered hyperbolic metamaterial in a vertical cavity surface emitting laser (VCSEL) to improve thermal conductivity and thermal dissipation thereby stabilizing optical performance. Improvement in the thermal management and power is expected by replacing the distributed Bragg reflector (DBR) mirrors in the VCSEL. The layered metamaterial structure performs the dual function of the DBR and the heat spreader at the same time.

A temperature-compensated laser driving circuit for driving a laser component is provided. The temperature-compensated laser driving circuit includes: a temperature compensation circuit, configured to generate a second current based on a first current and a temperature-independent current; and a modulation current generating circuit, configured to generate a modulation current based on the second current, and calibrate optical power output of the laser component based on the modulation current. The first current is proportional to the absolute temperature. The second current and the first current have a slope relative to the absolute temperature respectively, and the slope of the second current relative to the absolute temperature is larger than of the slope of the first current relative to the absolute temperature.

The specification and drawings present an apparatus and a method for protecting lasers or other sources of high optical power from damage due to external sources of contamination using a concept of a sacrificial optical component and automatic laser shutdown based on a pressure indication of a substantial damage to the sacrificial optical component such as puncturing through that component.

A manufacturing method for an excimer laser that includes a reflective Echelle diffraction grating includes obtaining information of a wavelength of a light source, a blazed order, a repetitive pitch of the grating, a material of the grating, and a predefined orientation ratio B/A that is a ratio between that a diffraction efficiency A of the blazed order and a diffraction efficiency Bb of an order lower by one order than the blazed order, and determining an initial value of a blaze angle based upon these pieces of information.

An intra-cavity frequency doubled OPS-laser includes a laser-resonator terminated by a plane mirror and a mirror-structure of an OPS-chip. The resonator is folded by three fold-mirrors. The fold-mirrors are supported on a vibration-isolation plate supported by isolation posts above a base-plate. The plane mirror and the mirror-structure of the OPS-chip are mounted back to back on opposite parallel surfaces of a mounting block. The mounting-block is supported on the base-plate and extends through an aperture in the vibration-isolation plate. Movement of the vibration-isolation plate with respect to the base-plate does not change the resonator length.

An EUV light generation system includes a driver laser comprising a master oscillator such as a semiconductor laser, a spatial filter, gas slab amplification devices, relay optical systems, and high-speed axial-flow amplifiers. The slab amplification devices include beam adjusting optical units disposed, respectively, at input and output sides of the slab amplifiers SA to convert the beam profile and/or polarization direction and/or an elongated direction of the beam profile with the slab amplifiers is parallel to a free space axis AF of the slab waveguides, i.e. parallel to the discharge electrodes.

A high power fiber laser system emitting a substantially diffraction limited beam with a Gaussian intensity profile includes a single mode (“SM”) neodymium fiber pump source outputting a SM pump light; a seed laser operative to emit a SM signal light at a wavelength greater than that of the pump light; a SM DWM receiving and multiplexing the SM pump and signal lights. The disclosed system further includes a booster fiber amplifier which is configured with a frustoconically-shaped ytterbium (“Yb”) doped core receiving the pump and signal lights and configured with a small diameter input end which supports only a SM and a large diameter output end which is capable of supporting the SM and high order modes (:HOM”). The booster further has a cladding surrounding and coextending with the core, the core being configured for having intensity profiles of respective SMs of pump and signal lights overlap one another so that an overlap integral substantially equals to one (1) along an entire length of the core. The SM of the light signal extracts substantially the entire energy from the pump mode leaving the HOMs without amplification necessary to affect a quality of the diffraction limited beam of the system in a MW peak power range and hundreds of watt average power range.

A method for quasi-synchronous tuning of wavelength or frequency of grating external-cavity semiconductor laser and a corresponding semiconductor laser are provided. A grating or mirror is rotated around a quasi-synchronous tuning point (Pq) as rotation center, so as to achieve the frequency selections by grating and resonance cavity in quasi-synchronous tuning, wherein the angle of the line between the quasi-synchronous tuning point (Pq) and a conventional synchronous tuning point (P0) with respect to the direction of light incident on the grating is determined according to the angle difference between the incidence angle and diffraction angle of light on the grating. According to present invention, approximately synchronous tuning of laser is achieved with a simple and flexible design.

An apparatus comprising an optical medium, a power splitter coupled to the optical medium, a first delay line coupled to the power splitter such that the power splitter is positioned between the first delay line and the optical medium, a first comb reflector coupled to the first delay line such that the first delay line is positioned between the first comb reflector and the power splitter, and a second comb reflector coupled to the power splitter but not the first comb reflector and not the first delay line. A method comprising receiving an optical signal, splitting the optical signal into a first split optical signal and a second split optical signal, delaying the first split optical signal, tuning the delayed first split optical signal, tuning the second split optical signal, and delaying the tuned second split optical signal.

A method for fabricating a group-III nitride semiconductor laser device stably supplies laser cavity mirrors having a low lasing threshold current through the use of a semi-polar plane. A blade 5g is forced down through a first region ER1 to keep the first region ER1 squeezed between a support member H2 and a movable member H1 together with a part of a protective sheet TF in contact with the first region ER1 while the tension generated in the area of the protective sheet TF in contact with the first region ER1 with the movable member H1 increases until the semi-polar principal surface SF at an end face EG1 of the first region ER1 tilts by a deflection angle THETA from the semi-polar principal surface SF of a second region ER2, and a force is thereby generated in the first region ER1 in a direction opposite to the direction of travel of the blade 5g toward the first region ER1. For example, an angle ALPHA is within the range of 71 degrees to 79 degrees, and the deflection angle THETA is within the range of 11 to 19.

A semiconductor laser includes a semiconductor nanowire of a first conductivity type provided over a substrate, a light emitting layer provided around the semiconductor nanowire and insulated at an upper end and a lower end thereof, a cladding layer of a second conductivity type different from the first conductivity type, the cladding layer being provided at an outer periphery of the light emitting layer, a first electrode electrically coupled to an end portion of the semiconductor nanowire, a second electrode electrically coupled to an outer periphery of the cladding layer, a first reflection mirror provided at a one-end portion side of the semiconductor nanowire, and a second reflection mirror provided at the other end portion side of the semiconductor nanowire.

A third-order distributed feedback laser has an active medium disposed on a substrate as a linear array of segments having a series of periodically spaced interstices therebetween and a first conductive layer disposed on a surface of the active medium on each of the segments and along a strip from each of the segments to a conductive electrical contact pad for application of current along a path including the active medium. Upon application of a current through the active medium, the active medium functions as an optical waveguide, and there is established an alternating electric field, at a THz frequency, both in the active medium and emerging from the interstices. Spacing of adjacent segments is approximately half of a wavelength of the THz frequency in free space or an odd integral multiple thereof, so that the linear array has a coherence length greater than the length of the linear array.

Singlet oxygen metastables can be formed. A catalytic coating is formed on an interior surface of a flow reactor, and an oxygen containing species is flowed into the flow reactor to produce singlet oxygen metastables by a chemical reaction in the presence of the catalytic coating.

An optical gain architecture includes a pump source and a pump aperture. The architecture also includes a gain region including a gain element operable to amplify light at a laser wavelength. The gain region is characterized by a first side intersecting an optical path, a second side opposing the first side, a third side adjacent the first and second sides, and a fourth side opposing the third side. The architecture further includes a dichroic section disposed between the pump aperture and the first side of the gain region. The dichroic section is characterized by low reflectance at a pump wavelength and high reflectance at the laser wavelength. The architecture additionally includes a first cladding section proximate to the third side of the gain region and a second cladding section proximate to the fourth side of the gain region.

Frequency standards based on mode-locked fiber lasers, fiber amplifiers and fiber-based ultra-broad bandwidth light sources, and applications of the same.

A pulsed smaser includes at least one optical resonator and an optical pump. The at least one optical resonator includes opposing mirrors, a solid state gain medium having a masing frequency in a range of from about 50 GHz to about 1 THz, and a Q-switch, wherein the solid state gain medium and the Q-switch are optically arranged between the opposing mirrors. The optical pump is arranged to provide optical pump power to the solid state gain medium. The optical pump and the Q-switch are configured to generate pulsed masing in the solid state gain medium at the masing frequency at room temperature to provide output electromagnetic radiation at the masing frequency.

A method to tune an emission wavelength of a laser diode (LD) finely is disclosed. The method first controls a temperature of the etalon filter in T1 or T2, where the transmittance of the etalon filter becomes 40 to 50%, assuming a height between the peak and the bottom of the periodic transmittance to be 100%, at the grid wavelength λ1 or λ2, respectively. Then, the temperature of the LD is adjusted such that the intensity of light emitted from the LD and transmitted through the etalon filter becomes 40 to 50%.

A GRINSCH laser having an asymmetric configuration wherein the optical confinement is weighted more to the n-doped multilayer section than to the p-doped multilayer section. The GRINSCH laser can emit laser light at a wavelength λ=976 nm over a broad area with a beam power of 11.4 W at a 12 A bias current at a temperature of 20° C. Fabry-Perot and distributed Bragg reflector GRINSCH laser configurations are disclosed.

Novel methods and systems for miniaturized lasers are described. A photonic crystal is bonded to a silicon-on-insulator wafer. The photonic crystal includes air-holes and can include a waveguide which couples the laser output to a silicon waveguide.

The invention provides a laser converter for converting a laser radiation of shorter wavelength to a laser radiation of longer wavelength using a single stage conversion. The laser converter comprises a laser diode for emitting a laser radiation in a first wavelength range, a cylindrical microlens for transferring and focusing the laser radiation to a laser chip and the laser chip for absorbing the laser radiation and emitting the laser radiation in a second wavelength range.

There is provided a surface emitting laser allowing a direction of a far-field pattern (FFP) centroid to be inclined from a normal direction of a substrate providing the surface emitting laser, comprising: a substrate; a lower reflecting mirror, an active layer, an upper reflecting mirror stacked on the substrate; and a surface relief structure located in an upper portion of a light emitting surface of the upper reflecting mirror, the surface relief structure being made of a material allowing at least some beams emitted from the surface emitting laser to be transmitted therethrough, a plurality of regions having a predetermined optical thickness in a normal direction of the substrate being formed in contact with other region in an in-plane direction of the substrate, and a distribution of the optical thickness in the in-plane direction of the substrate is asymmetric to a central axis of the light emitting regions.

Disclosed is an ASE-free continuously tunable external resonator laser in which reduction in tuning range and decrease in output are suppressed. The external resonator laser comprises: a fixed support body which has a half mirror that partially reflects incident light and partially transmits incident light fixed therein; and a rotatory support body which is rotatably supported by the fixed support body by way of a shaft, and which has a laser chip that emits light, a collimator lens that collimates light emitted from the laser chip, and a diffraction grating that diffracts light emitted from the laser chip, fixed therein.

Improved brightness and feedback multi-emitter laser diode modules and methods are provided. A plurality of laser diode emitters emit broad-area light beams in a beam direction. In cross-section, each beam is broad in its slow axis and narrow in its fast axis. Groups of downstream optical components collimate, shape, stack and direct the beams along a light path towards a beam spot (which may be fiber-coupled). After collimating, stacking and directing, the beams are Fourier transformed in the fast-axis through a lens feature having a fast-axis focal length less than about 3 millimeters. In some embodiments, the fast-axis focal length is between about 0.1 and 2.0 millimeters. Astigmatism may be introduced between the fast axis and the slow axis in the beams upstream of the lens feature and in accordance with the fast axis focal length of the lens feature. The emitters may receive feedback including wavelength locking feedback.

A light source for a photonic integrated circuit may comprise a reflection coupling layer formed on a substrate in which an optical waveguide is provided, at least one side of the reflection coupling layer being optically connected to the optical waveguide; an optical mode alignment layer provided on the reflection coupling layer; and/or an upper structure provided on the optical mode alignment layer and including an active layer for generating light and a reflection layer provided on the active layer. A light source for a photonic integrated circuit may comprise a lower reflection layer; an optical waveguide optically connected to the lower reflection layer; an optical mode alignment layer on the lower reflection layer; an active layer on the optical mode alignment layer; and/or an upper reflection layer on the active layer.

A semiconductor laser produces infrared radiation suitable for jamming a heat seeking missile, wherein a wavelength of the radiation is in a range of 2-5 microns, and the laser has a semiconductor lasing medium of Pb1-xSexPb1-xSnxSe or Ga0.84In0.16As0.14Sb0.86. These materials can be doped to provide a p/n junction, wherein the laser is excitable by electric current passing through the p/n junction. The third one of these materials can be constructed also as a uniform undoped slab which is excitable optically. Cooling of the lasing medium is accomplished by use of a lithium heat sink thermally coupled to the lasing medium by a diamond thermal diffuser which conducts heat from the relatively small region of the laser to spread out the thermal energy along a relatively large surface of the heat sink. Modulation circuitry is connected to the excitation apparatus to provide a pulse train of the radiation.

A device is provided to shape a spine of a book casing positioned horizontally spread out flat and oriented to be distributed evenly over a spine of a book block. Two fold-shaping rails are arranged extending in a direction parallel to one another. A movable, shaping tool is arranged to face the inside of the book casing spine to shape a web on the book casing spine with the aid of the two fold-shaping rails. The shaping tool includes two spaced-apart support bars that extend parallel to the fold-shaping rails and are arranged to be adjustable so that together they adjust the web width of the book casing spine in a direction transverse to the direction of extension of the fold-shaping rails.

In a device for cutting to length and feeding spine strips (3) for a case maker (1), a center strip conveying device (30) is provided that advances the spine strip material (5, 6) by the spine width (BS) transverse to the board feed direction (23) in a cyclic fashion. The spine width (BS) can be changed from work cycle to work cycle without accumulating additional waste. This can be realized because the previously required width sizing on the material web is eliminated.

A drill bit assembly has a bit head and a pin body. The bit head comprises a cutting end, an opposite connecting end with an engagement section, and a feature facing the connecting end. The pin body comprises a tubular body with an axial bore therethrough, a connecting end with an engagement section and a feature facing the connecting end. The drill bit assembly is manufactured by positioning the pin body connecting end with the bit head connecting end such that the pin body and bit head engagement sections overlap with a gap therebetween, and the pin body and bit head features are aligned; injecting a thermoplastic or other connecting material in liquid form between the bit head and pin body engagement sections and into the gap; and solidifying the thermoplastic or other connecting material such that the bit head and pin body are mechanically coupled together at their connecting ends and their features are securely aligned.

A female thread member capable of preventing seizing caused by inclined insertion, and being smoothly fastened from any directions in which a bolt is inserted, and a fastening member using the female thread member. A non-thread portion is formed on an inner peripheral surface of a female thread member body having a female thread for a length corresponding to at least one pitch from an end surface on a bolt-inserting side, and a projection which comes into contact with a flank surface of a male thread of an inserted bolt is formed on a line extending from a helical line of the female thread. The female thread member is used in combination with the bolt having no incomplete thread portion, and there is no adverse possibility of seizing regardless of any directions in which the bolt is inserted.

A security fastener, for use with a corresponding key, having a channel in a head of the security fastener for receiving the key, the bottom of the channel being profiled wherein the depth of the channel varies along the length of the channel; a key for use with a security fastener; a combination, or a kit of parts, comprising a security fastener; a method of manufacturing a security fastener; and a method of processing an order for a security fastener.

The blind rivet for fastening together a plurality of mounted components with mounting holes comprises a rivet body having a sleeve, a flange and a through hole; a mandrel having a slender stem and a head; and a washer. The head of the mandrel is adjacent to the sleeve-side end portion of the rivet body, the stem of the mandrel extends through the rivet body from the flange-side end portion, and the washer is mounted near the flange on the outer periphery of the sleeve of the rivet body. A portion of the outer peripheral surface of the sleeve adjacent to the flange is swaged to form a recessed portion so that the diameter in the other position is enlarged. The washer is pushed onto the enlarged-diameter portion and secured. The mounted components are fastened together between the enlarged end portion of the sleeve and the washer.

A fastening element includes a holding part with a support plate and expanding cheeks, and a locking part guidingly received in the holding part. The expanding cheeks include cantilevered walls formed adjacent the support plate, which are offset radially outwardly with respect to a guide wall of the support plate which guides the locking part. The locking part can be pushed through the support plate substantially without force until it reaches inwardly protruding ramp projections formed on the expanding cheeks, which provide a better lever ratio for spreading the expanding cheeks.

A fastening unit (1,101) for fastening an object to a profile element (80) with a longitudinal slot (85). The profile element having an upper side formed by a flanges which define between them the longitudinal slot. The fastening unit includes an oblong metal anchoring element (2) for engaging behind the flanges, a washer element (4) for engaging the upper side of the flanges and a support element. The support element (3) is connected to the anchoring element and associated with the washer element. The connection between the support element and the anchoring element includes two or more connecting legs (36) which are formed integrally with a body of the support element and extend each through an associated recess in the anchoring element. The connecting legs at their distal ends have a retaining lug (37) for preventing that the anchoring element can be released from the distal ends of the connecting legs. The support element comprises one or more spring elements (36) associated with the connecting legs and a stop surface (31a) for engagement with the upper side of the anchoring element. The one or more spring elements act to push the anchoring element from the underside away from the retaining lugs so as to bias the upper side of the anchoring element against the stop surface of the support element.

No flange damage wedge lock washers are disclosed. The washers may comprise an upper washer and a lower washer. The lower washer may have a generally smooth bottom surface and at least one means for securement. The at least one means for securement may be arranged to keep together the lower washer and a flange without causing damage to the flange. A locking fastener assembly which comprises no flange damage wedge lock washers is also disclosed. The locking fastener assembly may include a lower washer having a generally smooth bottom surface and at least one means for securement. A method of manufacturing a locking fastener assembly which comprises no flange damage wedge lock washers is also disclosed. The locking fastener assembly of the method may include a lower washer having a generally smooth bottom surface and at least one means for securement.

An assembly comprising at least two non-metal components which are fixed to each other using at least one fixing system. The fixing system includes a fixing device with a fixing element which is provided with a head and a rod, and a crimping ring which is in contact with one of the components. A protection device is a part of the fixing system which delimits a cavity for confining gas around a portion of the device comprising the crimping ring. In order to improve the repeatability of the operation for positioning the protection device, a guiding device is provided which includes an assembly element on the portion of the fixing device, and an element for guiding the protection device.

Bushing assemblies include a first tubular end portion, a second tubular end portion, and a middle tubular portion. The middle tubular portion has a longitudinal compressive strength that is less than that of the end portions. In some embodiments, the middle tubular portion is constructed of braided sleeving. Also disclosed are bushing assembly kits, apparatuses that include bushing assemblies, such as aircraft, and associated methods of utilizing bushing assemblies.

A threaded fastener for attaching an article of hardware to another article comprising a material selected for example from the group consisting of wood, particle board, plastic and fiberglass. The article of hardware is provided with at least one through hole and the article of hardware is fixed to the article by the threaded fastener extending through the through hole in the article of hardware. A shaft of the threaded fastener is provided with a thread that is not a self tapping thread cutting thread; and a tapered shank of the threaded fastener is provided with a self tapping thread cutting thread.

A fastener includes a cylindrical shaft, a screw head located at an uppermost portion of the cylindrical shaft and comprising a tool indentation therein, a threaded portion on the cylindrical shaft comprising a plurality of external threads, and a countersinking portion located between the threaded portion and the screw head and comprising a cutting section. The countersink portion is tapered from a first diameter equal to a diameter of the threaded portion to a second diameter that is equal to or larger than a diameter or a maximum width of the screw head. The countersinking portion is configured to form a countersink hole in a receiving material as the fastener is rotated and forced into the receiving material.

A method for applying compression to a joint includes providing an intramedullary fixation assembly having a proximal screw member positioned at a proximal end of the intramedullary fixation assembly and a lag screw member positioned at a distal end of the intramedullary fixation assembly. Medullary canals are drilled in a first and second bone and the medullary canals are reamed. The proximal screw member is inserted into the first bone and a drill is used create a dorsal hole in the first bone. The lag screw member is slideably coupled to the dorsal hole and to the proximal screw member and into the second medullary canal. A torque is applied to the lag screw member to apply compression to the joint.

A fastener for attaching objects to channeled members wherein the objects have a hole extending therethrough and the channeled members have a longitudinal slot formed between projecting longitudinal walls. The fastener includes a button and a retainer. The button includes an abutment wall, an abutment surface and an axially extending slot. The retainer includes an engagement boss and a head at opposite ends of shaft. The retainer extends through the button slot. For attaching the object, the button extends through the object hole with the abutment wall adjacent the object and the abutment surface adjacent the channeled member. The retainer boss and part of the shaft extend through the longitudinal slot. The retainer is rotated for engaging the longitudinal walls with the boss. The longitudinal walls are sandwiched between the boss and the button abutment surface and the object is sandwiched between the channeled member and the button abutment wall.

A showerhead electrode is provided where backside inserts are positioned in backside recesses formed along the backside of the electrode. The backside inserts comprise a tool engaging portion. The tool engaging portion is formed such that the backside insert further comprises one or more lateral shielding portions between the tool engaging portion and the threaded outside diameter to prevent a tool engaged with the tool engaging portion of the backside insert from extending beyond the threaded outside diameter of the insert. Further, the tool engaging portion of the backside insert comprises a plurality of torque-receiving slots arranged about the axis of rotation of the backside insert. The torque-receiving slots are arranged to avoid on-axis rotation of the backside insert via opposing pairs of torque-receiving slots.

A method and apparatus for an insulating cover for fasteners. In one advantageous embodiment, an apparatus comprises a washer and a cover. The washer is capable of receiving a fastener. The cover is capable of being secured to the insulating washer, wherein an insulating volume is created with the cover secured to the washer.

A protrusion anchor assembly is provided that utilizes a plurality of extendable pins to secure the anchor body within a bore in any hard material, such as concrete. The anchor body is rotated within the bore while the pins are simultaneously and gradually extended, carving out a groove or grooves within which the pins can sit. After installation, the device is secured within the bore by tightening a jamb nut against the surface of the concrete wall and in some embodiments placing a security plug within the anchor body to ensure that the pins are held in place. The pins prevent the anchor from being withdrawn because they act as protuberances that catch against the edges of the groove and cannot be drawn past that point.