Abstract: A heater of an external tubular sleeve for repairing a longitudinal section of defective hollow pipe has a frame for encompassing the sleeve when operationally positioned. Each of several burners spaced at intervals about the frame as nozzle for heating the sleeve, and a novel baffle located intermediate the nozzle and sleeve when operationally positioned, for heat dispersal over the sleeve. Each baffle has staggered vents for passing flame from the nozzle onto the sleeve, to avoid cold spots on the sleeve below the baffle, and has a central shaped deflector proximate the vents and facing the nozzle. Flame from the nozzle impacts the deflector and redirects toward the vents and periphery, of the baffle, to avoid point heating below the nozzle and provide diffused flame uniformly over the sleeve. Changing deflector and vent features can influence desired flame dispersal characteristics.

Abstract: A method of performing a localized post weld heat treatment on a weld seam in a thin wall metallic body may include attaching thermocouples to the outside surface of the weld seam and covering the weld seam with a thermal insulating blanket. Cooling bands are attached to the outside of the body on both sides of the weld seam. An inert atmosphere enclosure with inlet and exhaust ports is fitted over the weld seam, thermal insulating blanket, and cooling bands. A power supply and control system for an induction coil or coils situated in close proximity to the weld seam are actuated and the weld seam is subjected to a heat treatment without thermally affecting regions of the metallic body adjacent to the weld seam and external to the cooling bands.

Abstract: A method and apparatus for treating a selected region of a metal layer, used to form a metal card, by annealing the selected metal region so the selected region becomes soft and ductile, while the rest of the metal layer remains stiff. The softened, ductile, selected metal region can be embossed with reduced power and with reduced wear and tear on the embossing equipment. Alternatively, the annealed metal layer can undergo additional processing steps to form an assembly which can then be embossed. The method may include the use of a fixture for holding the metal layer, with the fixture having a window region for enabling heat to be applied to soften the region of the metal layer within the window region. The fixture includes apparatus for cooling the portion of the metal layer outside of the window region and for preventing the temperature of the metal layer outside the window region from rising above predetermined limits.

Abstract: A preheat burner assembly and method for preheating forming dies includes a frame, a burner manifold and a link assembly. The burner manifold as a plurality of burner orifices for preheating the forming dies. The burner manifold is connected to a fuel source. The link assembly mounts the burner manifold to the frame for movement between a stowed position and a deployed position. The burner is moved via the link assembly to a deployed position for preheating the forming dies. The forming dies are preheated. The burner manifold is subsequently moved via the link assembly from the deployed position to an upright stowed position.

Abstract: A Hookah Heat Management Accessory comprising a base plate configured to rest on the tobacco bowl sitting on the top of a Hookah and which conducts heat from charcoal, or other heat source, to the tobacco beneath it; an insulating wall connected to the base plate; an inner lid that mates to the aforementioned wall piece; and an outer lid that is loosely attached to the inner lid allowing for rotation, ventilation, and thermal regulation.

Abstract: An apparatus for heating a substrate during die bonding is disclosed. The apparatus comprises: a substrate carrier configured to hold the substrate; a heating device configured to heat the substrate; a first actuator for effecting relative motion between the substrate carrier and the heating device such that the substrate is relatively indexed with respect to the heating device; a second actuator for effecting relative motion between the substrate carrier and the heating device such that the heating device contacts the substrate to heat different portions of the substrate. In particular, the second actuator is operative to separate the heating device from the substrate in order for the first actuator to relatively index the substrate across the heating device. A method of heating a substrate during die bonding is also disclosed.

Abstract: A radiant panel for use in radiant heating and cooling systems that provides numerous benefits over conventional panels currently in use. The radiant panel comprises an offset hydronic radiant tube channel in which is nested a hydronic radiant tube that obviates the need to thread the hydronic tubes through the joists in a ceiling installation or the studs in a wall installation. In an alternative embodiment, specific emissivity coatings on each side of the radiant panel further promote the efficient transfer of heat. The system provides increased sound isolation and is robust enough to withstand the crushing forces associated with a floor installation.

Abstract: A system for bonding electrical devices using an electrically conductive adhesive to adhere the electrical devices together, the system including: an ultrasonic transducer to generate an ultrasonic vibration; and an ultrasonic to thermal energy apparatus operatively attached to and covering an operational end of the ultrasonic transducer, the ultrasonic to thermal energy apparatus damping the ultrasonic vibration to minimise ultrasonic vibration transmitted to a first electrical device and causing the conversion of the ultrasonic vibration to a heating pulse which is conducted through the first electrical device to the adhesive. Whereby the adhesive is softened by the heating pulse to bond the electrical devices together.

Abstract: The invention relates to a joining assembly for joining partners of a vehicle, including a first joining partner, at least one second joining partner, and a holding device by which the joining partners can be connected to each other to form the joining assembly, where the holding device includes a receiving structure on which at least one adhesive member is arranged, which can be brought into at least two states, where in a first state, the adhesive member allows an adjustment of the second joining partner on the first joining partner, where the change from the first state into a second state can be activated by transformation means, where in the second state, the adhesive member is cured, whereby fixation of the joining partners to each other can be achieved.

Abstract: An industrial oven system for curing composite material parts can include an oven compartment configured to receive a composite material structure therein that extends along a majority of the length and/or width of the compartment, the compartment having an inner wall that defines a cavity between proximal and distal ends of the compartment. A shroud can be disposed circumferentially between the inner wall of the compartment and an outer wall of the composite material structure. The shroud defines a first longitudinal annular channel between the inner wall and an outer surface of the shroud, and defines a second longitudinal annular channel between the outer wall of the composite material structure and an inner surface of the shroud.

Abstract: A heater supporting device for use in a semiconductor manufacturing apparatus is provided so as to improve the uniformity of a temperature property and the expected lifespan by preventing support pieces from being damaged and separated from piece holders, and preventing deterioration in adiabatic efficiency in the vicinity of a ceiling of a vertical type furnace. A heating element of a coil shape is disposed around an object. The support pieces are vertically connected in multiple. Hollows of an elliptical shape are formed between the respective support pieces. Concave insertions are formed on one of upper and lower surfaces of the respective support pieces, and convex insertions are formed on the other one of the upper and lower surfaces of the respective support pieces. The convex insertions are insert-fitted with the concave insertions. The support pieces are vertically connected in multiple by insert-fitting the concave insertions to the convex insertions.

Abstract: A method and apparatus for treating a selected region of a metal layer, used to form a metal card, by annealing the selected metal region so the selected region becomes soft and ductile, while the rest of the metal layer remains stiff. The softened, ductile, selected metal region can be embossed with reduced power and with reduced wear and tear on the embossing equipment. Alternatively, the annealed metal layer can undergo additional processing steps to form an assembly which can then be embossed. The method may include the use of a fixture for holding the metal layer, with the fixture having a window region for enabling heat to be applied to soften the region of the metal layer within the window region. The fixture includes apparatus for cooling the portion of the metal layer outside of the window region and for preventing the temperature of the metal layer outside the window region from rising above predetermined limits.

Abstract: The subject invention provides devices and methods for heating pipes, tubing or similar equipment. More specifically, the subject invention pertains to devices and methods for heating pipes, tubing or similar equipment to melt-out blockages, such as for example, bitumen blockages.

Abstract: A gas burner system for a heating device includes a burner, a valve assembly for controlling a flow of fuel to the burner, a blower assembly for directing air to the burner, and a control system. The burner includes one or more burner plates for facilitating the mixture of air and fuel to be combusted in a combustion chamber. The control system is configured to independently control the valve assembly and the blower assembly according to a control profile, for generating a plurality of air/fuel mixtures each configured for operation of the burner at a different firing rate. By mapping the characteristics of both the gas valve and the combustion blower independently, the burner system is assured of operating at the proper air/fuel mixture over a very wide range of firing rates, with a turndown ratio of 30:1 or greater, and within ANSI safety and performance standards.

Abstract: A warming system for high pressure storage tanks for hydrogen and CNG gas fuel wherein a warming device is installed upon a tank port that is interconnected in thermal communication with a metal liner within the tank and heat derived from an on board vehicle heat source is transmitted by conduction from the tank port to the tank interior. Heating ameliorates mechanical stresses to the tank and the component parts of the tank assembly caused by the thermal conditions of the tank environment and thermal changes in gas temperature associated with the depletion of high pressure gas from the tank.

Abstract: The subject invention provides devices and methods for heating pipes, tubing or similar equipment. More specifically, the subject invention pertains to devices and methods for heating pipes, tubing or similar equipment to melt-out blockages, such as for example, bitumen blockages.

Abstract: The present invention is a candle heater includes a heating element that is attached to a decorative cover. The heater is adjustable in size allowing it to fit around different sizes and shapes of candles at various positions on the container. The heater allows a person to melt a desired amount of the candle wax increasing the speed and safety of the heater. The heater presents various different ornamental designs which improve the aesthetics of the candle.

Abstract: A pipeline heater comprising a plurality of flameless catalytic IR emitters positioned about a section of pipe in a substantially diamond-shaped configuration, the diameter of the pipe section being greater than the diameters of the heater inlet and outlet manifolds in order to increase the residence time of the fluid within the heater. The pipeline heater may comprise a single or multiple passes of the pipe section therethrough, each pass having a plurality of catalytic emitters positioned thereabout in a substantially diamond-shaped configuration.

Abstract: A pipe heating apparatus for heating pvc pipe to facilitate bending. The pipe heating apparatus includes a housing having a lower portion and an upper portion, and at least one aperture extending through a wall of the housing. The lower portion includes a bottom wall for resting upon a horizontal support surface, and a lower perimeter wall extending upwardly from the bottom wall. Similarly, the upper portion includes an top wall and a upper perimeter wall extending downwardly from the top wall. The lower perimeter wall and the upper perimeter wall both have the same form and size. The upper portion may be positioned to rest upon the lower portion. Thus, an edge of the upper perimeter wall abuts an edge of the lower perimeter wall. The housing defines an interior space for receiving a portion of a pvc pipe.

Abstract: A hot water system for a narrowboat which system comprises an auxiliary heater used to heat a potable water tank and further to heat living areas of the narrowboat. The auxiliary heater and a temperature measuring device operable connected to the water tank which terminates operation of the heater when the temperature reaches a predetermined and comfortable level selected by the user. Likewise, a room water circuit is operably attached to the auxiliary heater and is operated by a thermostatically controlled solenoid valve which terminates hot water flow through a radiation within the living areas when the temperature reaches a value selected by the user.

Abstract: A preheating apparatus is disclosed which supports a hollow, cylindrical combustible heating element. A solid fuel mixture is used to generate hot gases for the heating of metal surfaces for pre-welding purposes. A grooveway is imbedded radially around the upper portion of the solid fuel mixture. An oxygen liberating pre-starter compound is housed in the grooveway for uniformity of ignition of the combustible solid fuel to permit a more uniform and consistent burn of the solid fuel during hot gas generation.

Abstract: A conveyor oven is heated by inshot burners, which eliminate blowers, ducts, and motors heretofore required to supply a force draft of combustion air to the burners. Apertures in front of the inshot burners have a diameter that regulates the amount of combustion air that is delivered to the burners. The only blower in the oven is the one required to circulate and recirculate hot air within the oven which produces three pressure zones that causes an induced draft of combustion air for the inshot burner. A modulating valve adjusts the flow of gas to the inshot burners.

Abstract: An axially rotatable materials handling apparatus for handling a mixture of solid particulate and water, includes a heater mounted on the housing that can transfer heat to the mixture to prevent or thaw frozen water inside the apparatus. The heater can be a combustible fuel heater or an electric heater. The apparatus is particularly useful in winter weather to prevent water from freezing inside the apparatus or to thaw any frozen water already present.

Abstract: A heating device for heat-sealing containers by heating an end forming portion 13 of a tubular container having a rectangular to square cross section, the end forming portion 13 having four generally quadrilateral first to fourth panels 21 to 24 continuous with one another and each having a heating region 31, 32, 33 or 34 to be heated on an inner surface thereof. The heating device has a hot air nozzle 71 in the form of a bottomed tube and fittable into the container end forming portion 13 for heating an inner surface of the container.

Abstract: A heating apparatus for heating rigid plastic pipe for the purpose of bending and forming the pipe. The heating apparatus includes an elongate housing that has a bottom wall, a pair of side walls, a first end wall, and a second end wall to define an interior. Each of the end walls has a pipe hole for permitting a user to insert rigid plastic pipe through the interior. An elongate burner member burns combustible gas to produce heat and is mounted to the housing and is positioned in the interior proximate to the bottom wall. A valve assembly regulates a flow of the gas to the burner member. An elongate burner plate disperses the heat generated by the burner member and is positioned above the burner member. A plurality of pipe support members support the pipe above the burner plate while positioned in the interior of the housing. An elongate cover member selectively covers the opening to the interior of the housing.

Abstract: An indirect radiant heating device burns gaseous or liquid fossil fuels for the heat treatment of running products, such as bars, tubes, and strips kept in a protective atmosphere. The device includes a radiant cassette of parallelepipedal shape, with a continuous radiating surface whose cross section, in a plane perpendicular to the axis of the cassette, is delimited by a continuous line which falls inside a rectangle whose height/width ratio is greater than 1.5.

Abstract: A micromachined fluid handling device having improved properties. The valve is made of reinforced parylene. A heater heats a fluid to expand the fluid. The heater is formed on unsupported silicon nitride to reduce the power. The device can be used to form a valve or a pump. Another embodiment forms a composite silicone/parylene membrane. Another feature uses a valve seat that has concentric grooves for better sealing operation.

Abstract: A heater box to bend PVC conduit in the form of an elongated metal box, split into upper and lower portions and hinged along one side so as to be openable for insertion of a segment of a plastic conduit lengthwise through the box, the box having, at either end, cutout portions so as to allow the closure of the box around the pipe. In one embodiment, corresponding semicircles are cut from upper and lower end portions of the heating box so as to allow a pipe segment to fit when placed therein. A burner located within the lower box portion extends along the elongated box to provide uniform heating. A baffle extends over the burner along its length. The box bottom and lower sides are perforated to provide combustion air. The hot combustion gases are directed upward around the baffle and up to the conduit segment. Supports, spaced along the length of the elongated box support the heating pipe segment above the hot baffle. These supports run perpendicularly underneath the plastic pipe while heating.

Abstract: An apparatus for heating plastic pipe includes an outer housing having distal first and second open ends and a diffuser plate mounted inside of and spaced apart from the top of the outer housing. An inlet extending through the housing is positioned for directing heated air to impinge on the diffuser plate. A mount positions the diffuser plate within the housing such that when the plastic pipe is disposed in the housing through the open ends of the diffuser plate does not contact the pipe. First and second end caps are disposed at the distal first and second open ends respectively. The end caps have first and second apertures therethrough for supporting and centering the plastic pipe such that the diffuser plate does not contact the pipe.

Abstract: Described is a heating apparatus which in case of need guarantees nonproblematic access to the objects to be heated, without incurring heat losses. Used in conjunction with lip rolling apparatuses, the heating apparatus features at least two movably arranged heating boxes (1) and (2), which via parallelogram linkages connected in swingable fashion to a stationary support element (13), such that in their inoperative position they are away from the object to be heated and have assumed closed position as well.

Abstract: A device for achieving vacuum conditions more quickly in a semiconductor processing system having a vacuum pump, a gate valve and a chamber includes a rigid body containing heating elements that contact the surface of the gate valve. The device may include a U-shaped retainer clip for holding the device to the gate valve. A method for heating a gate valve to drive off contaminants involves heating the lower portion of the gate valve to drive contaminants towards the vacuum pump.

Abstract: A liquid delivery system for delivery of an initially liquid reagent in vaporized form to a chemical vapor deposition reactor arranged in vapor-receiving relationship to the liquid delivery system.

Abstract: The present invention is a pipe heater that uses a combustible gas burner to provide heat to the pipe. The gas burner permits the heater to be portable and to be used in remote locations where a source of electricity is not readily available. The heater comprises a body adapted so that a pipe can extend therethrough and a burner to bend the pipe. Positioned between the burner and the pipe within the heater is a baffle having a plurality of holes therein. The baffle redirects the heat from the burner around the pipe, thus evenly heating the pipe. The heater is also provided with a control system to regulate the flow of fuel to the burner and potentially with a battery-powered or flint starter device. Furthermore, the body of the heater has air holes positioned in its sides and openings within its bottom to provide an air supply to the burner and to allow the burner to be lit if a starter is not provided or is inoperative.

Abstract: The oxygen-fuel torch includes a torch body having fuel gas and oxygen conduits for conducting the respective gas to the torch head and therethrough to a torch tip. The torch tip is connected through an adaptor to the torch head and includes an elongated tip stem that is joined to an arcuately curved tip head. The tip head extends angularly through an angle of at least about 245 degrees and has three outlet orifices opening toward a common point to direct three flames to substantially surround tubing for soldering or otherwise heating. If three orifices are provided, the orifices are angularly spaced about 120 degrees from one another.

Abstract: A method for cleaning a fixture utilized in an electrostatic spray painting process to remove adhered paint particles from the fixture utilizing inductive heating to heat the paint particles to a temperature sufficient to thermally decompose the paint particles to ash and gaseous combustion products. Also disclosed are apparatus for carrying out the method.

Abstract: A device for removing layers of paint from a surface including layers of paint which may comprise a base layer of oil paint. The paint is softened by radiation by means of at least one heating source. Immediately thereafter, the paint is removed mechanically from the surface. The apparatus comprises a carrier which may retain one or more sources of infrared radiation, a device for guided travel of the carrier in the horizontal plane along the painted surface and a device for guided travel of the carrier in the vertical plane along the painted surface.

Abstract: An improved heating method and heating nozzle useful in the forming of a two-piece thermoplastic foam cup assembled from two thermoplastic foam pieces on a cup-forming turret machine. The method and apparatus of the invention prevent premature sticking of the foam bottom piece to the foam sidewall piece and result in better sealing of the foam bottom to the sidewall.

Abstract: A hot-air generating tool for use with heat-shrink tubing in electrical wiring applications device includes a heat source such as a disposable butane lighter, a body member having a top portion and a bottom portion, the bottom portion adapted for releasable capture of the heat source, and the top portion including an exhaust nozzle oriented over the heat source and adapted to direct a stream of air over the heat source. A heat reflector member is connected to the body member by a reflector arm and is adapted to deflect the heated air stream from the heat source and exhaust nozzle to a target area. A mouth piece member is connected to the exhaust nozzle by a length of tubing, so that when a user ignites the heat source and delivers a stream of air through the mouth piece, the air is delivered through the exhaust nozzle, over the heat source, and towards the target area.

Abstract: A zone heating device has first and second spaced burners for heating first and second spaced sides of a metal plate during forming of a thickened edge along the edge of the metal plate. The first and second burners are elevationally movable by an actuator between first and second spaced transverse positions relative to the sides of the metal plate. An actuator moves the zone heating device along a trackway in directions transverse the plate edge. A fixed guide under the bias of the actuator engages the edge of the metal plate and maintains the first and second burners at a predetermined location relative to the plate edge. A movable guide maintains the first and second burners at another preselected location relative to the plate edge. A control device controls movement of the first and second burners, the zone heating device, and the movable guide in response to preprogrammed instructions. The zone heating device is particularly suited for use on a forming apparatus.

Abstract: A method is provided for heating and transferring a substantially flat workpiece made of a deep drawable plastic material including the steps of enclosing at least a substantial portion of the workpiece between first and second opposing carrier plates such that a gas-tight seal may be formed by one of the carrier plates about the substantial portion of the workpiece and supplying hot gases through a gas distribution conduit associated with the first carrier plate while withdrawing hot gases through a gas distribution conduit associated with the second carrier plate such that the workpiece is heated and transferred to the second carrier plate. The workpiece is then transferred to a third carrier plate or a deep-drawing device.

Abstract: A heating device for recovering a heat-recoverable plastics sleeve about a portion of a wire harness comprises a housing having a heating location when the portion of the harness and heat-recoverable sleeve are introduced, and a heating unit that is movable between a rearward position in which it surrounds the heating location. The heating unit comprises a pair of heating jaws (5,5') that open as they move toward the heating location and then close as they arrive at it so that the portion of the harness to be heated is completely enclosed within the heating unit. The jaws open again when they recede from the heating location to allow the harness to be removed.

Abstract: In the heat treatment in the field of a thermite weld between rail ends, the rail ends and the weld are enclosed within a containment filled with an aluminothermic material mixture. The mixture is ignited and the rail ends and the thermite weld are heat-treated for a given period. After the given period, the aluminothermic reaction products and the containment are removed, and an air quench unit is placed about the weld and rail ends and compressed air is directed at the weld and rail ends for a given time period. After the removal of the air quench unit, the weld is allowed to cool to ambient temperature.

Abstract: A loader device for an automatic space treatment furnace having a longitudinal axis and means for driving the furnace in guided translation along said longitudinal axis. The loader device is disposed in the vicinity of the furnace and comprises both a cartridge-carrying carousel fitted with a set of cartridge holders removably receiving sealed closed cartridges each designed to contain a sample for treatment in said space furnace, the cartridges being disposed in the carousel parallel to its axis of rotation, and a control mechanism for imparting indexed rotary drive to the cartridge holders. The carousel is itself mounted relative to the furnace in such a manner that its axis of rotation forms a predetermined angle a relative to the longitudinal axis of the furnace, and each cartridge holder of the carousel co-operates with a tilting mechanism to enable each cartridge to take up a working position in which the axis of the cartridge is tilted through said predetermined angle .alpha.

Abstract: A method and apparatus for heat stretching a synthetic fiber rope. The rope is buoyed in a vessel containing a liquid medium, and this is heated to a predetermined stretching temperature. Tension is applied to the heated portion of the rope so as to stretch this to a predetermined increase in length. The process may be batchwise, or it may be continuous. In the batch process, a length of the rope is stretched in the heating vessel by a draw rod. In the continuous process, feed and take-up capstans pass the rope through a heating chamber, and then through a cooling chamber. The capstans are operated at different speeds so that the rope is tensioned and stretched between them within the vessel.

Abstract: A method for temperature conditioning a blank of plastic material in which a conditioning mandrel is placed within the blank and thereafter expanded into reliable abutment against the inner surface of the blank. The mandrel is thereafter returned to its initial position. The outer surface of the mandrel is adjusted to and maintained at a certain temperature, whereby, during the abutment, an energy exchange takes place between the blank and the mandrel for adjusting the temperature of the blank. At high temperatures of the mandrel, the mandrel is displaced out of the blank after such short time that the plastic material in the region of the abutment surface never passes the critical temperature of tackiness of the plastic material and/or thermal crystallization of the plastic material. As a rule, the expansion and contraction of the mandrel is repeated one or more times.

Abstract: A device for trapping reaction products and especially for generating and trapping decomposition products from thermal decomposition processes, including combustion, is described. Decomposition products of a solid sample are formed at the top end of an externally heated vertical decomposition tube and are channeled downward through a region of decreased diameter in which a trapping device is positioned. The trapping device consists of two vertical concentric tubes of which the top end of the inner tube is slightly lower than that of the outer tube. Water flows upward between the two concentric tubes, traps the decomposition products at the top, and drops down through the inner concentric tube. Products contained in the water are collected externally from the lower end of the trapping device for analysis. The insoluble gaseous products are collected by an external vacuum system after passing through the stream of water.

Abstract: A process and apparatus for heating injected, cold preform blanks composed of partly crystalline synthetic resins which have been produced by injection molding. The preform blanks are positioned in holders on a conveyor and are rotated about their longitudinal axes as they are moved along the conveyor, heated to blow mold temperature in multiple stages including a series of heating and cooling stations on respective opposite sides of the conveyor so as to be heated from one side of the conveyor and cooled from the other side while being carried on the conveyor and while being simultaneously rotated whereby they are uniformally heated across their cross sections. The process is completed by tempering and producing a protective surface on the preform blanks before they are supplied to a blow molding device. The entire process requires only several minutes of time.

Abstract: A suction adhesion-type holder used, for example, in a bonding machine including an air cooling device provided between a bonding stage and a vacuum pump that creates a vacuum suction in the bonding stage through the cooling device. Air suction holes formed in the bonding stage, that has a heating element, are connected to the air cooling device via a pipe and air heated by the bonding stage is cooled in the air cooling device when the heated air flows in a spiral pipe installed inside the cooling device and then sucked into the vacuum pump. The spiral pipe is cooled by a fan.

Abstract: A support is provided for supporting the lower header plate and adjacent tube ends of a radiator core within an oven area for even heating thereof preparatory to manually pry and scrapping softened epoxy material from the header plate and about the tube ends. A method also is incorporated wherein after the original epoxy has been removed, fresh epoxy is applied to the header plate about the tube ends and allowed to cure.

Abstract: A clamp for tightening heating coils around a cylindrical object being heated has a split tubular housing with straps extending from each housing edge and forming loops pulled together by forces exerted from a pair of wedging elements with conical surfaces. The wedging elements have a cylindrical portion journalled in loops connected to one housing edge and a conical inner portion on which a strap connected to the other housing edge is mounted. Movement of the wedging elements axially with respect to one another changes the effective diameter of the conical portions engaging the strap. This causes the housing edges to be pulled together. Movement of the wedging elements with respect to one another is provided by securing one element to a mounting pin and providing a threaded bore through the other element, the element with the bore being restrained from rotation. When threads on the pin engage the threaded bore, the elements are pulled together.