Abstract: A fuel injecting device and method of controlling the fuel injection device. The fuel injection device includes a cylindrical body, a needle whose end includes with a head forming a valve on a seat supported by the end of the cylindrical body, an actuator made of an electroactive material, including a rod and that displaces the head such that the valve is opened, and a prestressing device holding the needle and a counterweight such that they are pressed against the rod opposite end. The needle extends coaxially to the cylindrical body in a form of a rigid bar and axially resonates when exposed to axial pulses at a determined excitation frequency by the actuator.

Abstract: A selectively automatic fire fighting nozzle a method of use including adjustable means (ST) of limiting a range of automatic adjustment (B) of a discharge orifice of the nozzle, providing an option of selecting a constant pressure for a first fraction of a discharge window and selecting a relatively constant flow for a second fraction.

Abstract: A delivery system for a medicament or well-being enhancing composition, comprising a flexible member, means for attaching the flexible member to fabric to form a pocket and an absorbent pad for impregnation with the medicament or well-being enhancing composition arranged such that when the flexible member is attached to a piece of fabric a pocket is formed shaped and sized such the pad may be received and held securely within the pocket but is removable therefrom. The fabric is typically part of a garment or bed-linen.

Abstract: A fuel injector and servovalve for an internal combustion engine.

Abstract: A micro-droplet generator comprises a main body, having a chamber accommodating liquid to be sprayed and a lateral opening, a spraying plate, placed in the opening and having a plurality of spraying holes as well as an inner side, a vibrating element, glued on the spraying plate and driving vibrations thereof, and a projection, placed inside the chamber and having an outer side touch with the inner side of the spraying plate, wherein a narrow space is left between the inner side of the spraying plate and the outer side of the projection, which upon the vibrations of the spraying plate has a varying width, upon becoming wider sucking in liquid from the chamber, and upon becoming narrower pressing out liquid through the spraying holes.

Abstract: A fuel injection valve includes a body having a high pressure fuel passage and a nozzle hole, which is connected to the passage, a nozzle needle opening/closing the hole and having a needle piston part, a piezo stack extended when the stack is charged and contracted when the stack discharges electric charge, a cylinder, in which the needle piston part is slidably inserted and which is driven by the stack, a fixed piston having a fixed piston part that is slidably inserted in the cylinder and that has a larger diameter than the needle piston part, an oil-tight chamber between the needle piston part and the fixed piston part in the cylinder, and a nozzle spring urging the needle in a valve closing direction. The cylinder is displaced due to extension/contraction of the stack, so that volume of the chamber increases/decreases and the needle opens/closes the hole.

Abstract: A remote boom lock assembly is provided to secure a boom assembly supported on an agricultural vehicle or implement. The boom lock assembly is generally configured to move between a locked position and an unlocked position relative to the boom assembly as it is seated in a boom cradle structure mounted on the agricultural vehicle. The boom lock assembly includes a boom lock element mounted to the boom cradle structure, and an actuator assembly configured to selectively move the boom lock element from a locked position to an unlocked position. A remote switch is employed to control operation of the actuator assembly. The boom lock assembly further includes a spring configured to bias the boom lock element toward the locked position.

Abstract: A cartridge for an admixing arrangement of a manually operable arrangement for spraying a solvent, in particular water, into which an additive in the form of a liquid concentrate, such as a plant or crop protection agent, has been mixed, includes an outer cartridge housing; a pressure-sensitive inner container for accommodating the liquid concentrate; a mixing chamber, the mixing chamber having a device with a first outlet opening, for the concentrate or plant spray, an inlet opening, designed as a throttle, for the solvent or water, and a second outlet opening for the concentrate/solvent mixture.

Abstract: A valve seat 14 having an injection hole 14b is fixed at one end of a hollow valve main body 15, a valve body 12 slidably supported so as to be separated from and brought into contact with the valve seat 14 to open and close the injection hole 14b and a swirler 16 for surrounding the valve body 12 to slidably support the valve body 12 and for imparting a swirling motion to fuel flowing into the injection hole 14b are equipped, a swirling groove 16b in the swirler 16 includes a curvature part 16b3 in a groove outlet, and a sectional configuration of the swirling groove 16b is constituted so that the depth of the central part is larger than the depth of the end part.

Abstract: A method for fabricating a nozzle includes providing at least two plates. At least one of the at least two plates includes a first opening. Each plate includes at least one mating surface. The method also includes stacking the at least two plates together such that a mating surface of a first of the at least two plates is substantially flush against a mating surface of a second of the at least two plates, and such that a fluid passage is at least partially defined by the at least two plates. The method also includes orienting the at least two plates relative to each other such that the opening within at least one of the at least two plates at least partially defines an outlet for discharging fluid from the fluid passage.

Abstract: An electrostatic paint sprayer 10 includes a body member 12 defining a paint passage 12a for flowing liquid paint supplied from a paint source 44, a nozzle assembly 16 adapted to be mounted to the end of the body member 12 so as to fluidly communicate with the paint passage 12a and a plurality of electrode pins 22 disposed about the axis and electrically connected to a electric power source 40. The nozzle assembly includes a paint orifice for discharging the supplied paint along an axis, a plurality of atomizing air orifices for discharging atomizing air to atomize the paint dispensed through the paint orifice and a plurality of shaping orifices for discharging shaping air to form the paint dispensed through the paint orifice into a predetermined pattern.

Abstract: Disclosed are efficient and cost-effective methods of recovering primary construction materials from whole carpet. The present methods are particularly appropriate for recovering nylon or polyester face fibers from post-industrial, post-consumer carpet waste.

Abstract: A shredder adapted to encourage the settling of shredded material therein and method of shredding material.

Abstract: A spice grinding and dispensing device generally intended to be used for grinding one spice in a first portion and a second spice in the other portion. Each portion of the dual spice grinder includes a handle or trigger that activates an independent rasp mechanism. When the trigger is pressed, the rasp activated thereby moves down and forces ground spice through an opening. The pressure of the rasp against the inside of the bottom of the grinder breaks up the spice, and only spice that is properly sized can fit through the opening. Furthermore, the opening may be adjustable so that a user can create a coarse or finely ground spice.

Abstract: A stirring or dispersing device (1), has a hermetically sealed mixing chamber (5), a tool (2), and a drive mechanism (4) located outside of the mixing chamber (5). The tool (2) can be driven around a central shaft in the mixing chamber (5) which has a rod-shaped element (3) for force transmission from the drive mechanism (4) to the tool (2). The rod-shaped element (3) is connected at the entry to the mixing chamber (5) with a diaphragm (6), which is a part of the wall (7) of the mixing chamber (5), and the rod-shaped element (3) can be put into a wobbling movement by the drive mechanism (4), so that its end located in the interior of the mixing chamber (5) performs a rotating movement. The tool is constituted by a number of grinding elements (22) or balls to be introduced into the mixing chamber (5).

Abstract: A layered tape guide spool having a plurality of guide rods, each of which have a first and a second guide member. The gaps between adjacent guide rods and the gaps formed between the first and second guide members define a gap that urges the tape stacks together into a desirable rectangular shape. The resulting tape stacks are then wrapped onto a tubular core or onto existing layers on a tubular core.

Abstract: A fishing reel that employs a non-contact line sensor to capture images of the backlash zone of a baitcast fishing reel, together with image analysis and feedback to a direct contact spool brake, with the result of gradual to near-instantaneously halting spool rotation, thereby decreasing or preventing backlash under all fishing conditions while maximizing cast distance.

Abstract: A reverse prevention mechanism is configured to prevent reverse rotation of a drag disk, in a line-releasing direction, when braking a spool. The reverse prevention mechanism includes a rotation member, a pawl member, and an urging member. The rotation member includes an outer periphery portion with a plurality of engaging members. The outer periphery portion is arranged between the second pinion gear and the drag disk, and is capable of rotating integrally with the drag disk. The pawl member is pivotally coupled to the reel unit. The pawl member is arranged in an engagement position and a remote position. In the engagement position, reverse rotation is prevented when the pawl member is engaged with the outer periphery portion of the rotation member. In the remote position, the pawl member is detached from the outer periphery portion. The urging member urges the pawl member toward the engagement position.

Abstract: A seatbelt retractor for storing seatbelt webbing that can be utilized to restrain an occupant of a motor vehicle. The retractor includes a retractor frame and a plurality of spools rotatably coupled to the retractor frame and spaced a distance apart from each other. Seatbelt webbing can be withdrawn from the seatbelt retractor to extend about an occupant of a seat of the motor vehicle and releasably coupled to a buckle provided to the motor vehicle in a withdrawn state, and collected by the seatbelt retractor in a retracted state. A length of the seatbelt webbing adjacent to a terminal end thereof is collected at least partially around the plurality of spools in the retracted state.

Abstract: A cable reel mechanism includes a main body, a cable reel, a cable, a volute spring and a switching element. The main body has a receiving room defined therein and a limiting groove. The cable reel is turnably disposed in the receiving room of the main body and has a track groove in which a ball bearing is disposed. One portion of the ball bearing engages with the limiting groove of the main body. The cable is reeled on the cable reel. The switching element is disposed on the main body and has a pressing portion which detachably presses the ball bearing. The cable reel mechanism can be switched to different operation modes via the switching element, so that users can pull then retract the cable rapidly and directly to adjust the length of the cable, therefore the operation is easier and more convenient.

Abstract: A rotation control device for pet leash includes a casing, a cover, and a wheel disposed in the casing. The casing includes a locking button, an unlocking button, and a self lock slider connected with a locking spring, an unlocking spring, and a self lock spring respectively. The unlocking button has an unlocking retaining hole having a position corresponding to an unlocking column on the casing. The unlocking button includes an unlocking retaining pole is inserted into an unlocking sliding groove of the casing. The locking button has a locking retaining rectangular hole having a position corresponding to a locking column on the casing. The self lock slider includes a self lock retaining pole is inserted into a self lock sliding groove in the casing, wherein the self lock retaining pole is against an unlocking retaining pole.

Abstract: A cart for supporting and transporting spools of wire in a stable manner comprises a base having a wire spool supporting frame and wheels thereon, the base having a first section and a second section with the first section being located forward of the second section when the base is in use; a plurality of wire spool supporting arms on the frame; and a second plurality of wire spool supporting arms mounted on the frame at a location that is between the first plurality of wire supporting arms and the base and which is located closer to the second section of the base than to the first section of the base.

Abstract: A device is provided for use in covering a danger area on a roll changer that can carry at least one roll of material to be directed to a rotary, web-fed printing press. A cover is provided with a drive that can move the cover. A control unit is provided to control the drive for the cover. The cover is closed in a first operational state and is open in a second operational state. The roll of material, that is supported by the roll changer, has a first rotational speed or web speed when the cover is in the first, closed operational state. In the second, cover opened, operational state, the roll of material also has a second rotational or web speed which is greater than zero. A method for controlling a device on a roll changer is also disclosed.

Abstract: A transmission device includes: a transmission shaft having first and second shaft sections and a gear mounting portion; a first tube sleeved rotatably on the first shaft section, and including a tube body and an annular portion; a second tube sleeved on the second shaft section; a plurality of first planetary bevel gears mounted rotatably on the gear mounting portion; a plurality of second planetary bevel gears mounted rotatably on the annular portion; a transmission gear disposed rotatably on the tube body and meshing with the first and second planetary bevel gears; a first output bevel gear disposed rotatably on the second tube and meshing with the first planetary bevel gears; and a second output bevel gear disposed rotatably on the tube body of the first tube and meshing with the second planetary bevel gears.

Abstract: A system for reducing distortion at the aerodynamic interface plane of a boundary-layer-ingesting inlet using a combination of active and passive flow control devices is disclosed. Active flow control jets and vortex generating vanes are used in combination to reduce distortion across a range of inlet operating conditions. Together, the vortex generating vanes can reduce most of the inlet distortion and the active flow control jets can be used at a significantly reduced control jet mass flow rate to make sure the inlet distortion stays low as the inlet mass flow rate varies. Overall inlet distortion, measured and described as average SAE circumferential distortion descriptor, was maintained at a value of 0.02 or less. Advantageous arrangements and orientations of the active flow control jets and the vortex generating vanes were developed using computational fluid dynamics simulations and wind tunnel experimentations.

Abstract: A turbojet-mounting pylon for an aircraft. The pylon includes a rigid structure including a plurality of arcs arranged so as to jointly delimit a part of a fictitious approximately cylindrical surface with a circular section. The plurality of arcs also includes two lateral thrust resisting arcs located on each side of the central box, each of the two lateral arcs being fixed to each arc in the form of an annular portion, and on each side of the central box.

Abstract: A rigging for moving an aircraft panel relative to an aircraft substructure includes a retaining base attached to a panel interior, and a slider rod held in contact with the substructure and adjustably engaged with the retaining base. The slider rod is manipulable from the panel exterior to adjustably engage the panel in a rigging position along a fair axis. The slider rod may include a tool appurtenance captively positioned within the riser bore that is exteriorly manipulable through a panel access port. Tool appurtenance manipulation may actuate the slider rod to adjustably engage the support hub and to move the panel into the fair position. A fit plate may be attached to the aircraft panel disposed intermediate to the retaining base, and may be adjustably attached to the aircraft panel for moving the aircraft panel into a fit position in a rigging plane.

Abstract: A pod for an aircraft including a cowling, an engine housed in the inner volume of the cowling, an annular channel circulating a secondary thrust flow arranged between the engine and the cowling, and at least one thrust reverser for forming a reverse flow from the secondary thrust flow circulating in the annular channel. The thrust reverser including a plurality of doors provided in the rear part of the cowling, so as to form a trailing edge of the cowling. The thrust reverser can include means for actuating the doors such that at lease one actuating means actuates two adjacent doors and at least one door is actuated by two actuating means.

Abstract: The present invention relates to a front aircraft part (1) comprising a non-pressurised landing gear housing zone (28) designed to house a front landing gear (30) in a retracted state, as well as a pressurised zone (2) adjacent to the non-pressurised landing gear housing zone. According to the invention, the pressurised zone is delimited by a set of walls among which only a substantially flat-shaped sealed partition wall (10) also participates in delimiting the non-pressurised landing gear housing zone (28).

Abstract: A vehicle including a body having an exterior surface and a protrusion extending outward from the surface. The vehicle further includes a fairing mounted on the surface directly adjacent and behind the protrusion. The fairing has a forward end, an aft end opposite the forward end, and opposing sides extending between the forward end and the aft end. The opposing sides become progressively closer together from the forward end to the aft end so that the bracket has a tapered shape.

Abstract: A security cover is disclosed for protecting installed avionics instruments and other electronic instruments. The cover includes multiple independent automatic locks that activate when the cover is abutted near the installed instruments. An automatic lock mechanism, adapted to electronic instrument covers, is also disclosed. The activated locks are not directly accessible to users and thieves. A lock release mechanism is disclosed for simultaneously unlocking each lock. A method of manufacturing using extruded aluminum panels is disclosed.

Abstract: A system and method for detecting debris on the surface of a member are provided, for example, for detecting ice or other debris on an outer surface of an aircraft. The detection system includes a heating device in thermal communication with the member, an infrared sensing device configured to sense infrared radiation emitted from the member, and a monitoring device in communication with the sensing device. The monitoring device is configured to monitor a change in emission from the member and thereby detect the presence of debris on the surface of the member.

Abstract: The invention relates to a self-contained device (4) for blanking out the light rays from at least one star (1), which device (4) comprises means (43) for controlling propulsion means (44) which are in turn capable of moving or halting the device (4) in space and/or on a pseudo-orbit in space around an observation telescope (2) comprising an observation opening (21), characterized in that it comprises a blanking-out screen (40), wherein the means (43) for controlling the propulsion means (44) are further capable of positioning the screen (40) on the sighting axis (3) between the telescope (2) and the star (1) during an observation period such that the light rays from the star (1) are at least partially blanked out during said observation period as far as said observation opening (21) is concerned. The invention further relates to an assembly comprising at least one such device and a method for using said device or said assembly.

Abstract: An apparatus for converting a manned aircraft of a type including at least one pilot control capable of manipulation to affect operation of the aircraft for unmanned flight operations includes first and second actuators, each configured to selectively provide movement or resistance to movement in a first manner including linear or rotational motion, first and second clutches, each configured to selectively couple movement of the associated actuator to the pilot control, and a vehicle controller capable of being selectively enabled to operate the pilot control actuators and clutches and thereby provide unmanned operation of the aircraft, or of being disabled, thereby providing for manned operation of the aircraft. The first actuator has a first scope describing a first amount of allowable movement, while the second actuator has a second scope larger than the first scope.

Abstract: A bracket (100) for mounting a light-emitting member (50) to a computer enclosure, includes a first holding member (10) and a second holding member (30) connecting with the first holding member via a connecting arm which is capable of being fold to cause the first holding member to overlap and detachably engage with the second holding member to hold the light-emitting member (50) therebetween. Each of the first and second holding members forms a pair of hooks configured for engaging with the computer enclosure.

Abstract: The present invention relates to a retainer or holder for positioning a line on a structural component, a line guiding system for reducing sag in line guiding, and an aircraft having at least one line, which is equipped with a line guiding system according to the present invention. In addition, the present invention relates to the use of the line guiding system according to the present invention in an aircraft. The holder essentially comprises a main body, a bracing element and an engagement element. The bracing element projects from the bottom side of the main body and divides the main body globally into a cantilever section and a support section. The engagement element is adapted to be received frictionally locked by a reception opening in a structural component.

Abstract: A clamp for connecting a pair of orthogonally disposed pipes. The clamp may comprise a pair of identical clamp halves or brackets, or a pair of mirror-image clamp halves or brackets, each bracket having a centrally located plate portion having one or more apertures, an upper surface, a lower surface and spaced apart ends, each of the ends carrying a curved jaw designed to conform to cylindrical outer surfaces of the pipes. The lower surfaces of the plate portions of the pair of clamp brackets are disposed in confronting relationship with their apertures in alignment, the pair of brackets being coupled with one or more fasteners passing through the aligned apertures. The end jaws of one of the brackets are in opposed relationship with the corresponding end jaws of the other of the brackets, wherein the end jaws of the coupled brackets define a pair of generally cylindrical pipe gripping surfaces each having a longitudinal central axis.

Abstract: A tube clip is mounted to a channel-section track and is used to secure a pipe. The channel-section track includes a pair of upper engagement surfaces having inwardly turned flanges spaced apart by a slot. The tube clip includes an integrally molded, one-piece elongated cylindrical body that extends along a first axis and defines a center bore for receiving the pipe therethrough. A base is fixedly secured to the cylindrical body and includes a pair of support surfaces spaced apart along the first axis. Each support surface includes a fin for engaging one of the upper engagement surfaces of the channel-section track to bias the tube clip therefrom. A pair of flexible legs extends from the base portion. The legs are spaced apart along the first axis and each leg is adapted to selectively lockingly engage one of the flanges when the tube clip is mounted to the channel-section track.

Abstract: In an embodiment of the present invention there is disclosed a mounting assembly for a sprinkler reducer. The assembly includes a mounting bracket having a locking unit, a latitudinal support bar to which the mounting bracket is movably coupled, and a pair of longitudinal support units which are coupled to opposite ends of the support bar.

Abstract: An exemplary stand includes a housing (51), a sliding member (52), four connecting subassemblies (58, 59), and a spring (56). The housing (51) has two opposite guiding slots (516). The sliding member is slidably disposed in the housing. Part of each connecting subassembly extends in one corresponding guiding slot of the housing and the sliding member, such as to slidably connect the sliding member to the housing. Each connecting subassembly includes two wheels (584) rotatably received in the guiding slots. One end of the spring is connected to the housing, and the other end of the spring is sleeved on the sliding member or the connecting subassemblies.

Abstract: The invention relates to a swing away mail box post which is simple to operate and manufacture. It includes two parts: a stationary base; and, a rotating stem (the latter of which is attached to the mailbox post itself). There is only one moving part, the stem rotates on the base as you desire. You just set the desired direction upon base installation by relying on a directed notch or keyway that interacts with a stem mounted screw to bias the location of the stem with respect to the base post. The installation of the base is straight forward, and the stem is adaptable to any standard type mailbox post, i.e., 3? round metal, 4?×4? wood, and 3½?×3 ½? P.V.C. sq. type post. This mailbox post system also includes two base configurations, one for stable packed soil, grass, etc. and one for sandy (i.e., loose) soil.

Abstract: A supporting framework has at least one roller which is carried by a carrying frame. The roller has an axis positioned generally along the horizontal direction in the use position. An axial extension projects out of each opposite end of the roller. The carrying frame has a pair of opposite, generally vertically extending bearing limbs, each bearing limb having a bearing opening. Each axial extension of the roller extends into one of the bearing openings of the bearing limbs. Lateral guide elements are provided at the two opposite ends of the roller. Each lateral guide element has a radially projecting lug which can be moved between an active position and an inactive position. The lugs can prevent a workpiece from moving past the ends of the roller when the lugs are in the active positions.

Abstract: A hair dryer stand for setting an operating blow-dryer on a countertop without burning the countertop or material on the countertop. The hair dryer stand is attractive and improves safety. The stand comprises at least one base, at least one sidewall having a top and a bottom where the bottom is attached to the base, at least one vent, and an opening wherein the opening profile is defined by the top of the sidewall and can receive the intake side of a blow-dryer that is turned on. In use, the blow-dryer is supported in the opening and suspended above the countertop. Air is allowed to flow into the intake side of the blow-dryer, over the heating coils inside blow-dryer and prevents the blow-dryer from overheating. Also, the exhaust side of the blow-dryer is directed upward, away from the countertop so the countertop or material on countertop will not burn.

Abstract: A stabilization device is provided that includes a resilient body that has an upper surface and a lower surface. The body includes a first set of teeth located on the upper surface and distributed about a first axis. The teeth are spaced apart from one another by a selected pitch. The body also includes a second set of teeth located on the upper surface and distributed about a second axis. Like the first set the second set of teeth are spaced apart a selected second pitch. The first and second sets of teeth are offset from each other along either the first or second axis. The lower surface of the body preferably includes a similar arrangement of teeth.

Abstract: An exemplary electronic device (30) includes a main body (40) and two supporting mechanisms (60). The supporting mechanisms are formed at two adjacent corners of the main body respectively. Each supporting mechanism includes a support leg (62), a positioning leg (64), and an elastic member (65). The support leg is rotatably connected to the main body, and configured for supporting the main body. The positioning leg is rotatably connected to the support leg, and configured for supporting the support leg. The elastic member is resisted between the support leg and the positioning leg, thus producing an elastic force to drive the positioning leg away from the support leg.

Abstract: A base (110) for a support foot (100) for supporting heavy bodies on a support surface, comprising a cap (115) intended in the use to be mechanically coupled to coupling means (105) of the base to a body to be supported. The cap is made of a first material of mechanical properties such as to guarantee that the cap is able to support, remaining substantially within the limit of elastic deformability, a first significative fraction of a load received by said coupling means to the body to be supported, and has said concavity on the side that, in the use, faces the support surface. A synthetic material mass (210) is arranged in adhesion to the cap and it is adapted to substantially fill the concavity of the cap, forming a contact surface (215) with a support surface.

Abstract: The present invention is an adjustable hanger bar assembly for a light fixture. The assembly maintains structural integrity between first and second bars to support a recessed light fixture while being extended to distances where typical mounting assemblies fail. The hanger bar assembly comprises first and second bars which slidably engage one another. One of the first and second bars comprises a foldable foot which may be extended to increase the length of the hanger bar assembly.

Abstract: A clip assembly having first and second clip members. In an example embodiment the first and second clip members are generally matching. Each clip member includes a mounting member adapted to envelope and slide along an edge of an associated mounting support, such as a ceiling T rail. Each clip member further includes a spacer member arranged generally parallel to the mounting member. The clip members are adapted to be mutually engaged by the engaging means included in respective spacer members when the first and second clip members are drawn together as a result of the respective mounting members sliding toward each other along opposed edges of the mounting support. The clip assembly is secured to the mounting support by an external screw and capable of being easily released from it, when necessary.

Abstract: A vehicle wash system having a plurality of vehicle treatment components includes with at least one support member. The support member is constructed of a base material and has an outer surface. An elongated cover includes an interior surface and an exterior surface. The interior surface of the elongated cover has a first color and a size and shape that substantially matches the outer surface of the support member. The elongated cover is readably engageable with the support member to protect it from contact with fluid and debris. The elongated cover is formed of a readably cleanable material such that fluid and debris can be easily wiped off of its exterior surface.

Abstract: The invention relates to improvements in tiltable wall mounts, and in particular to a self-locking tiltable wall mount for a screen, such as a plasma display or television screen. The tiltable wall mount for a screen comprises wall attachment means for attaching the mount to a substantially vertical surface and screen attachment means for attaching a screen to the mount. The screen attachment means are pivotally connected at one end to one end of the wall attachment means. The wall mount also has a tilt mechanism interconnecting the mount and screen attachment means, said tilt mechanism comprising a locking device comprising at least one cam follower which is biased into abutment with a stepped cam surface projecting from the wall attachment means to prevent relative movement between the wall and screen attachment means.