A step-down regulator comprising a pseudo constant on time control circuit is disclosed, comprising an on-time generator configured to receive a switching signal provided by the step-down regulator and a control signal provided by the pseudo constant on time control circuit, and generates an on-time signal; a feedback control circuit configured to receive a feedback signal representative of the output voltage of the step-down regulator and generate an output signal; and a logic control circuit coupled to the on-time generator and the feedback control circuit to receive the on-time signal and the output signal and generating the control signal, and a power stage configured to receive an input voltage and the control signal and generate the switching signal.

A power-supply circuit for a DC appliance includes an input unit including a first terminal and a second terminal so as to receive a DC current, an output unit including a third terminal to output the DC current entered by the input unit and a fourth terminal, a connection unit including a first conductive line and a second conductive line so as to interconnect the input unit and the output unit, a rectifier unit including first to fourth diodes coupled as a bridge diode format so as to rectify the input DC current in a predetermined direction, an inductor unit that is connected in series to the rectifier unit in such a manner that the input DC current is gradually increased from an abrupt change time point of the DC current, and a condenser unit that is connected in series to the inductor unit.

An integrated power quality control system includes a transformer with a primary winding, a secondary winding and a compensation winding wound on a magnetic core. A power electronic converter in the system provides a reference voltage to the compensation winding for injecting a series voltage in the secondary winding of the transformer. A controller is utilized to generate a reference control voltage for the power electronic converter based on a power quality control requirement.

A bridge-less step-up switching power supply device includes (i) a first and a second reactor having: a first and a second main winding connected to a first and a second input terminal, respectively; and a first and a second auxiliary winding magnetically coupled to the first main winding and connected to the first and second main windings, the first and second auxiliary windings having a first and a second leakage inductance, respectively; (ii) a first and a second diode connected between the first and second auxiliary windings and a first output terminal, respectively; (iii) a first capacitor connected between the first output terminal and a second output terminal; (iv) a second capacitor connected between a connection point of a third switch and a fourth switch, and the first output terminal; and (v) a controller for controlling turning on/off of first to fourth switches.

A switched mode power supply provides a reduction of switching losses and increased efficiency. The switched mode power supply includes a first switch coupled to an input terminal configured to receive an input voltage, a second switch, an inductor and an output capacitor. The first switch and the second switch are coupled together at a node, the inductor is coupled between the node and an output terminal, and the output capacitor is coupled to the output terminal. The switched mode power supply further includes a transformer coupled between a control input of the first switch and the node and a pulse generator connected to a control input of the second switch. Further, the transformer includes at most two windings, in particular a primary winding and a secondary winding which are not directly connected to each other.

There is provided a DC-DC converter which converts an input voltage into an output voltage for supply to a load, in which an input terminal receives the input voltage, an output terminal outputs the output voltage, power stages each includes: a high side switch, a low side switch and an inductor, the control unit executes a first mode and a second mode wherein the first mode controls the high side switch and the low side switch in each of the power stages so that a ratio of an output current in each of the power stages to a load current flowing through the load becomes a set value and the second mode controls the high side switch and the low side switch in each of the power stages so that duty ratios of the high side switch and the low side switch are equalized among the power stages.

A low-dropout voltage regulator includes a power transistor configured to receive an input voltage and to provide a regulated output voltage at an output voltage node. The power transistor includes a control electrode configured to receive a driver signal. A reference circuit is configured to generate a reference voltage. A feedback network is coupled to the power transistor and is configured to provide a first feedback signal and a second feedback signal. The first feedback signal represents the output voltage and the second feedback signal represents an output voltage gradient. An error amplifier is configured to receive the reference voltage and the first feedback signal representing the output voltage. The error amplifier is configured to generate the driver signal dependent on the reference voltage and the first feedback signal. The error amplifier includes an output stage that is biased with a bias current responsive to the second feedback signal.

A power control circuit for a power supply system including a control unit, a driving circuit and a power supply unit is disclosed. The power control circuit includes a current detection unit, a voltage detection unit and a power detection unit. The current detection unit is used for detecting a current signal. The voltage detection unit is used for detecting a voltage signal. The power detection unit is connected with the current detection unit, the voltage detection unit and the control unit for acquiring a power signal according to the current signal and voltage signal. By comparing an adjustable power reference signal with the power signal, the control unit issues a control signal to the driving circuit. In response to the control signal, the power supply unit is driven by the driving circuit to output an adjusted power to the load according to the adjustable power reference signal.

A mode controller shifts, along with increase in an electric power in first and second of chopper circuits and, operation modes of the first and the second of the chopper circuits from a first mode to a third mode via a second mode. An operation controller causes, in the first mode, the first of chopper circuit to perform an chopping operation, and the second of chopper circuit to suspend the chopping operation, in the second mode, causes the first and the second of chopper circuits to alternatively perform the chopping operations, and in the third mode causes both of the first and the second of chopper circuits to perform the chopping operations.

An unmanned, towable aerovehicle is described and includes a container to hold cargo, an autogyro assembly connected to the container and to provide flight characteristics, and a controller to control operation the autogyro assembly for unmanned flight. The container includes a connection to connect to a powered aircraft to provide forward motive force to power the autogyro assembly. In an example, the autogyro assembly includes a mast extending from the container, a rotatable hub on an end of the mast, and a plurality of blades connected to the hub for rotation to provide lift to the vehicle. In an example, an electrical motor rotates the blades prior to lift off to assist in take off. The electrical motor does not have enough power to sustain flight of the vehicle.

Systems and methods for activating a down hole tool in a wellbore. A piston is moveable from a first position to a second position for activating the down hole tool. The piston includes a first side exposed to a first chamber, and a second side exposed to a second chamber. A rupture member has a first side exposed to the first chamber and a second side exposed to a third chamber. The rupture member is configured to rupture when a pressure differential between the first chamber and the third chamber reaches a predetermined threshold value, at which point the rupture member allows fluid communication between the first chamber and the third chamber. When the rupture member is intact, the piston is in the first position, and when the rupture member ruptures, the piston moves to the second position and activates the down hole tool.

A casing window assembly for completion of a lateral wellbore. The casing window assembly includes a tubular casing sleeve with a casing window and an inner sleeve releasably secured within the casing sleeve at a pre-released position adjacent the casing window.

The well pump flow sleeve assembly provides a method of quickly fitting a flow sleeve to a well pump. The sleeve is made by cutting a pipe normal to the pipe centerline of the pipe surfaces, to a length appropriate for the well pump length. A pump centering bottom cap is inserted into the pipe lower opening and the well pump assembly is then inserted into the pipe upper opening and mates with the bottom cap to align the pump in the sleeve. The pump is now completely within the sleeve with the pump discharge and electrical connection extending through the pipe upper opening. Two flow sleeve cap halves are then fitted around the pump discharge and electrical connection/safety rope to form an upper cap which is inserted into the pipe upper opening. The submersible pump is then ready for service.

A tool for actuating a blow out preventer includes one or more connections for receiving hydraulic power from a remotely operated vehicle (“ROV”), a first pump for increasing pressure of an operating fluid for the blowout preventer (“BOP”), a second pump for increasing flow rate of the operating fluid, and a conductor for transporting the operating fluid to the BOP. The tool rapidly increases the pressure and flow rate of the fluid flowing to the BOP, and the BOP may be rapidly closed.

An apparatus and method for the actuation of down-hole tools are provided. The down-hole tool that may be actuated and controlled using the apparatus and method may include a reamer, an adjustable gauge stabilizer, vertical steerable tools, rotary steerable tools, by-pass valves, packers, whipstocks, down hole valves, latch or release mechanisms and/or anchor mechanisms.

The present invention relates to an inflow control device for controlling the flow of fluid into a well tubular structure arranged in a borehole, comprising a tubular part for mounting as part of the well tubular structure, an aperture provided in a wall of the tubular part, and a hollow valve member rotatably received inside the tubular part, the hollow valve member comprising an orifice in a wall thereof, and an outer surface of the hollow valve member being spherical and the orifice being adapted to fluidly communicate with the aperture when the inflow control device is in an open position, whereby the aperture is in fluid communication with an inside of the tubular part, wherein the hollow valve member comprises a spherical first valve part and a spherical second valve part adapted to be assembled inside the tubular part. The present invention furthermore relates to a method of assembling an inflow control device according to the invention and to a completion system comprising an inflow control device according to the invention.

A flow control device comprises a fluid pathway configured to provide fluid communication between an exterior of a wellbore tubular and an interior of the wellbore tubular, a flow restriction disposed in the fluid pathway, wherein the flow restriction is disposed in a radial alignment with respect to the wellbore tubular, and a flow blockage disposed in the fluid pathway, wherein the flow blockage substantially prevents a fluid flow through the fluid pathway.

A power winch horizontal-pull clutch device provides dynamic forces from a power source and uses a deceleration device to retard the force transmission to a cable pulley for releasing and rewinding a steel cable on the cable pulley. A connecting slot is formed on a casing of the deceleration device. The deceleration device includes an outer ring body and at least one insert slot formed on an external surface. The power winch includes a clutch device for selectively fixing the connecting slot to the insert slot to transmit the dynamic force from the deceleration device to the cable pulley. The clutch device is a sealed assembly and a control handle is provided for making a horizontal movement to achieve the clutching effect and prevent water, dust or other foreign matters from entering into the clutch device, damaging components, causing failure or malfunction, or clamping an operator's hand or foreign matters.

An apparatus of the present invention is used for movable objects upwardly and downwardly relative to a fixed surface. The apparatus includes a lifting device presented by a pair of blocks movable relative one and the other. A carriage device is supported by the blocks. The carriage device is connected to object to be lifted relative the fixed surface. An actuator is connected to the blocks. As the actuator moves the blocks relative one and the other, the blocks move above the carriage device relative the fixed surface at various distances lift and lower the objects.

A manual marine winch includes a safety knockout override preventing release of winch tension without the handle in stowed position. The winch includes a housing; a rotating drum on the housing; a winch line on the drum; a control for spooling and un-spooling the winch line on the drum, wherein the control includes a handle for selectively tensioning the drum and moveable between a position engaged with the drum and a disengaged stowed position; a tension holding mechanism on the housing comprising a ratchet gear coupled to the drum, a pawl selectively engaged with the ratchet gear, and a knockout configures to selectively disengage the pawl from the gear to allow for release of winch tension; and a safety knockout override coupled to the housing and selectively engaged by the handle and configured to prevent release of winch tension when the handle is not in the stowed position.

An apparatus for raising and lowering a carrier for supporting clothes hangers or other hanging articles within a wardrobe closet that includes a tube, brackets for rotatable mounting of the tube, a tubular motor coupled to the tube for rotating the tube, and a base that attaches to a side panel of the wardrobe closet. Two arms each lie on a plane parallel to the base and to the side panel, attach at their ends to the carrier, and are mounted on the base so that they may oscillate and pivot in the plane between two positions, raising and lowering the carrier. At the lowest position the carrier releases from the arms and drop further. Fabric straps are wound onto and unwound from the tube to raise and lower the arms as the tube is rotated. A remote control receiver or programmable device may be used to control operation of the motor.

An eyebrow shaping method includes providing an image of a face. Three guidelines are determined on the image and thee points are located via the guidelines. An eyebrow is shaped to have Golden Ration proportions via the three points.

The present invention relates to a rotary powder container with a brush, wherein powder is discharged through a brush of a powder discharge case by rotating an internal case containing powder in an external case. The internal case is able to be rotated in the external case, wherein powder is discharged into a brush when a plurality of discharge holes of a powder discharge case are in line with a plurality of discharge member holes of a powder discharge member if the internal case is rotated in the external case, and powder is not discharged into a brush when the plurality of discharge holes of the powder discharge case are not in line with the plurality of discharge member holes of the powder discharge member if the internal case is rotated in the external case. The present invention is convenient to use and has an elegant look.

An ultra-fine nepheline syenite powder produced from a pre-processed nepheline syenite powder feedstock. The powder having a “controlled” maximum grain size D95 or D99 of less than about 20 microns and a “controlled” minimum grain size D5 in the range of 2-8 microns with a particle size spread D5-D95 of less than about 12 microns.

A hydraulic binder includes, in parts by mass: (a) from 20 to 60 parts of Portland clinker; (b) from 20 to 40 parts of slag; and (c) from 0 to 60 parts of inorganic material other than the clinker and the slag; the sum of (a), (b) and (c) being equal to 100 parts; which binder further includes a slag activator including, relative to 100 parts of the sum of (a) and (b): from 1.4 to 6.55 parts of alkali metal salt, expressed as equivalent-Na2O; and from 1.1 to 11.0 parts of calcium sulfate, expressed as SO3.

A raw batch composition for concrete or concrete wherein the raw batch composition comprises Portland cement of about 15 wgt. % to about 45 wgt. % and dune sand preferably red dune sand is present in an amount of about 40 wgt. %. The dune sand has a particle size of less than or equal to 45 microns. The composition also includes limestone powder ranging from about 15 wgt. % to 45 wgt. % with particle sizes less than or equal to 45 microns to form a base material. To this base material suitable amounts of fine aggregate, coarse aggregate, water and superplasticizer are added. A method for producing a cast concrete product having a compressive strength of between 62 MPa and 90 MPa is disclosed. The method comprises a step of providing Portland cement, dune sand and limestone powder.

A colorant composition for tinting or coloring surface coverings or paint is. provided that has a low volatile organic compound (VOC) concentration, alkylphenoi ethoxylate surfactants (APE) free and hazardous air pollutants (HAPS) free. Additionally, the colorant composition has performance properties substantially equal to or better than tinters possessing high VOC concentrations. The colorant composition includes a colorant component, a dispersant including a polyamide, a surface active agent, water, and optional additives, The polyamide is a high molecular weight polyamide.having at least two anchoring amines, and the surface active agent includes phosphoric acid, phosphate esters, or salts thereof.

Method, apparatus, and system for preparing a cellular material based on hollow metal beads. According to the description, at least one bead chain in which said hollow metal beads are linked to one another in pairs by means of an articulation is used as elementary structure constituting the cellular material.

A power tool for installing a metal locking tie is disclosed. The power tool includes a body and a power chassis. The body of the tool includes a gear carrier, a tensioning mechanism and a cutting mechanism. The gear carrier is positioned in the tool body and the tensioning mechanism is mounted in the gear carrier. The cutting mechanism engages the gear carrier. As the tie is tensioned, the gear carrier moves linearly in the tool body to cut the tensioned tie.

A boom truck includes a telescopic lifting boom with a lifting unit and a support structure having a first support arranged on the chassis of the boom truck. A second support in the form of an elongated bearing and support beam body extends in the longitudinal direction of the boom truck. The beam body is pivotally mounted to the first support about a rear bearing axis, whereas the lifting boom is pivotally mounted to beam body about a front bearing axis. Actuators act on the beam body and the lifting boom as a unit and act to pivot the lifting boom about the front bearing axis.

A power generator is associated with a crane boom at or near the tip of the boom. The generator responds to movement of the lifting cable to initiate the transmission of a signal to a crane controller. The signal serves as a start-up or a wake-up signal to the crane controller which may then immediately analyze operation of, for example, an anti-two block device associated with the boom tip. The crane controller may then control the operation of the crane in accordance with signals received from the anti-two block device or immediately identify malfunctions of the anti-two block device and control the crane operations accordingly.

Embodiments of the invention generally relate a method and apparatus for a tower structure. In one embodiment, the tower structure comprises a first base plate comprising a first hinge device, a first structural section having a first side and a second side, the first structural section coupled to a second base plate comprising a second hinge device, a second structural section coupled to the first structural section, and an aerial component coupled to the second structural section, wherein the first structural section is rotatable relative to the first base plate in a first rotational axis, the second structural section is rotatable relative to the first structural section in a second rotational axis, and at least a portion of the second structural section is received in a channel formed in the first side of the first structural section when the first structural section and the second structural section are substantially parallel.

A luffing-jib tower crane, comprising a tower and a jib which is connected to the tower via a joint and is held by a luffing cable, wherein the length of the luffing cable can be changed by a drawing-in unit, by the luffing cable being wound onto or unwound from a cable drum of the drawing-in unit, wherein the angle of the jib with respect to the horizontal plane is measured by a first sensor winch is attached to the jib (first angular value), wherein a measuring device measures the length of the unwound part of the luffing cable, from which length the minimum angle of the jib with respect to the horizontal plane (second angular value) can be calculated, and the first angular value can be compared with the second angular value.

A rotary distributor device for a hydraulic power steering, which receives oil from a pump and sends the oil selectively to a discharge or to an actuator of the steering in a desired direction, comprises a jacket, a slide, sealedly rotating in the jacket, a series of openings that cross the wall of the jacket, located in front of a series of corresponding openings which cross the wall of the slide, elastic member located between the jacket and the slide configured to maintain the openings of the jacket at the openings of the slide, in which each opening in the jacket includes, in succession starting from the outside, at least one radial hole, a slot lying in a radial plane, arranged symmetrically with respect to the axis of the hole, the width being smaller than the diameter of the hole, and the depth being such as to intersect the hole.

A one-handle valve cartridge has a low point of contact for installing the valve cartridge in a valve body. A retention nut bears down on the low point of contact to secure the valve cartridge in the valve body.

The Invention provided is a hydraulic powered down hole reciprocating pump traveling valve component to provided lifting hydraulics on the down stroke using the derived motion and pressure of petroleum liquids and gasses, such as oil, water and natural gas and also utilizing the frictional traveling forces driven by the surface equipment. Designed to utilize the elements within the pumping apparatus to obtain the hydraulic power within and transfer the energy's force to the exposed bottom end of the pressure locked traveling ball valve adjacent within the ball valve containment cage, providing ultimate lifting power to open the ball valve on the initiation of the down stroke. The component consist of a Hollow Hydraulic Power Shaft, Hollow Pressure Motion House, and a Fluid Cavity Power Drag Plunger.

Disclosed herein is an improved method for reversed flow through a self-adjustable (autonomous) valve or flow control device (2), comprising the step of providing an overpressure on the side of the valve (2) opposite of the side of the inlet (10) exceeding a predetermined biasing force of the resilient member (24) causing lifting of the inner body part (4a) within the outer body part (4b) against said biasing force from a first position of fluid flow between an inner and an outer side of the valve (2) via the flow path (11) and to a second position of reversed fluid flow between said inner and outer side through the second flow path (25). An improved self-adjustable (autonomous) valve or flow control device (2) and use of said improved valve or flow control device are also disclosed.

A control valve having a retainer for securing a seat ring within the valve body of the device is disclosed. The seat ring is disposed within a bore in the fluid flow path of the valve body of the control valve, and the retainer is attached to the inner surface of the valve body to retain the seat ring within the bore. The retainer includes threaded openings therethrough for receiving bolts that are tightened down on the seat ring to hold the seat ring against the inner surface of the bore and/or a gasket to form a tight seal and prevent leakage when the control device is in the closed position.

Systems, methods and apparatus for providing an electromagnetic flow controller. In one embodiment, an electromagnetic flow controller can have two substrates, a permanent magnet, and two electrical traces. One of the substrates may deflect away from the other substrate upon applying an electrical signal to at least one of the two electrical traces.

Vascular treatment and methods include a plurality of self-expanding bulbs and a hypotube including interspersed patterns of longitudinally spaced rows of kerfs. Joints between woven structures and hypotubes include solder. Woven structures include patterns of radiopaque filaments measureable under x-ray. Structures are heat treated to include at least shapes at different temperatures. A catheter includes a hypotube including interspersed patterns of longitudinally spaced rows of kerfs. Heat treating systems include a detachable flange. Laser cutting systems include a fluid flow system.

Disclosed is a method for producing a high strength synthetic strength member (7) containing rope (1) capable of being used with powered blocks where such rope has lighter weight and similar or greater strength than steel wire strength member containing ropes used with powered blocks. Disclosed also is the product resulting from such method. The product includes a synthetic strength member, a first synthetic portion (9) and a second synthetic portion. The first synthetic portion is enclosed within the strength member and the second synthetic portion is situated external the strength member. At least a portion of the second synthetic portion also is situated internal a sheath (8) formed about the strength member. The second synthetic portion has a minimal of 8% at a temperature of between negative 20 and negative 15° C.

Vascular treatment and methods include a plurality of self-expanding bulbs and a hypotube including interspersed patterns of longitudinally spaced rows of kerfs. Joints between woven structures and hypotubes include solder. Woven structures include patterns of radiopaque filaments measurable under x-ray. Structures are heat treated to include at least shapes at different temperatures. A catheter includes a hypotube including interspersed patterns of longitudinally spaced rows of kerfs. Heat treating systems include a detachable flange. Laser cutting systems include a fluid flow system.

Data representative of a train consist (the train consist comprising a plurality of locomotives and a plurality of cars) and data representative of a route for the train consist can be processed by a processor to automatically determine which locomotives in the train consist should be powered on and which locomotives in the train consist should be shut down for each segment of the route. The processor can make these determinations based on an analysis of the train consist data and the route data with respect to a plurality of considerations that affect train efficiency. Recommendations for locomotive startups and shutdowns in accordance with such automated determinations can then be presented to the train crew for the crew to use during train operations. It is believed that when train crews are in compliance with such recommendations, significant improvements in efficiency, particularly with respect to fuel consumption, can be achieved.

A distributed power (DP) control system is contained within a non-freight carrying intermodal container for communicating with and receive instructions and/or commands from a command system of a lead distributed power locomotive within a train. The container is configured to be provided on a car adjacent to a remote non-distributed powered (non-DP) locomotive provided within a length of the train. One or more connection hoses connect the distributed power control system within the container to the non-DP locomotive to control application of at least its brake system.

An insulated window buck with integrated fastening and anchor elements for a self aligning cut or molded insulated concrete form (ICF) window buck. The insulated window buck with integrated fastening and anchor generally includes an insulated ICF window and door buck made with multiple components with a configuration that allows for the use of various type of materials' on the face and edges of the buck, and have the ability to friction fit to the inside of an ICF wall so as no external bracing or strapping is needed to keep the buck aligned with the ICF wall during concrete placement. Having a firm insulation material component on the internal portion of the buck is an integral part of the invention in that through the use of recesses in the insulation material the fluid concrete can flow into these recesses and make a permanent bond to the buck. Also having the ability to use single or multiple insulation pieces to make up the insulating and friction fit element of the buck is an integral part of the invention.

Provided are a polycrystalline silicon ingot casting mold and a method for producing a polycrystalline silicon ingot casting mold, with which high-quality silicon ingots can be obtained at high yields by minimizing sticking with the surfaces of the silicon ingot casting mold, and losses and damages that occur when solidified silicon ingot is released from the mold. The method for producing a polycrystalline silicon ingot casting mold having a release layer, including: forming a slurry by mixing a silicon nitride powder with water, coating the surface of the mold with the slurry, and heating the mold at 400 to 800° C. in an atmosphere containing oxygen, after coating the slurry.

A polycrystalline silicon ingot casting mold, and method for producing same. Mold release material being obtained by blending a silicon nitride powder (A) having an average particle diameter along the short axis of 0.6 to 13 μm with a silicon nitride powder (B) having an average particle diameter along the short axis of 0.1 to 0.3 μm at a weight ratio of 5:5 to 9:1; coating the mold surface with the slurry; and a heating the mold at 800 to 1200° C. in an atmosphere containing oxygen.

Disclosed is a double linkage triggering system including a main body, which has a trigger unit and a shooting unit. The trigger unit is capable of being contacted with the shooting unit. The trigger unit comprises a bracket body, a trigger block, a hammer, a trigger power-adjusting bolt, a triggering mechanism and a trigger-safety device. The hammer is hinge connected to the bracket body. The trigger block is hinge connected to the bracket body and each end of the trigger block is respectively capable of being limited by the hammer and the trigger power-adjusting bolt. The shooting unit has a sight stand, a guide device, a pressure plate, a rotary latch, a roof plate, a latching plate, a returning device, and an anti-empty shooting mechanism. The returning device is inserted into the roof plate. The roof plate is hinge connected to the latching plate.

A portable device to compress a bow comprising a pulley system with a block and tackle and fixed pulleys which, by wiring, are connected to a set of fastening supports with fastening ends. The fastening ends fasten and pull the ends of the arms or limbs of a bow, under traction exerted by the block and tackle. The block and tackle has a drive portion and a brake controlling the traction and release of the cables connected to the fastening supports. Upon pulling the drive portion, the block and tackle produces the approach between the first and the second pulleys. This displacement between the pulleys acts on the cables which, through the fixed pulleys, cause the approach between the fastening supports. This displacement of the fastening supports overcomes the resistance of the bow and compresses it. Once the desired compressive level is reached, the brake or blockage is actuated.

A toy projectile launcher assembly has the form of a crossbow. The crossbow only launches the safety projectiles that are provided. The launcher body has a handle at a first end and diverging support arms at an opposite second end. An adjustment mechanism is contained within the launcher body for selectively adjusting the length of the launcher body. The crossbow has diverging support arms. Bow arms are attached to the support arms. The bow arms pivot from retracted positions to extended positions when a projectile is loaded into the toy crossbow. The toy crossbow has elastic loops that can only engage specialized safety projectiles with side. Furthermore, the trigger mechanism can only engage the safety projectiles provided with the toy. Projectiles without a specific tab and keyhole cannot be loaded into the toy crossbow.