Abstract: A mounting sleeve fits around a nozzle extending along an axis and a heating coil wrapped around the nozzle and having an outer surface generally centered on the axis. The a mounting sleeve has a sleeve-shaped bimetal body having inner and outer layers and a pair of angularly juxtaposed edges. The body is shaped and dimensioned to fit around the coil with the inner layer engaging the coil outer surface. The inner layer has a smaller coefficient of thermal expansion than the outer layer so that when heated the body contracts radially inward. Interengaging formations at the edges generally prevent radial outward expansion of the body when interengaged.

Abstract: A mounting sleeve fits around a nozzle extending along an axis and a heating coil wrapped around the nozzle and having an outer surface generally centered on the axis. The a mounting sleeve has a sleeve-shaped bimetal body having inner and outer layers and a pair of angularly juxtaposed edges. The body is shaped and dimensioned to fit around the coil with the inner layer engaging the coil outer surface. The inner layer has a smaller coefficient of thermal expansion than the outer layer so that when heated the body contracts radially inward. Interengaging formations at the edge generally prevent radial outward expansion of the body when interengaged.

Abstract: A method of making a heater element has the steps of inserting into a smooth tubular casing a heating wire, filling a space between the wire and the casing with a compressible insulating mass, and closing ends of the space to confine the mass in the casing. Then the casing is radially inwardly compressed to form therein a successive of radially outwardly open annular grooves extending circumferentially fully around the casing and thereby radially compressing the insulating mass. The casing is formed with a succession of such grooves, which can be of V-shape and which are each endless so that the casing is corrugated. Alternately the grooves are interconnected helically. Either way in accordance with the invention the grooves form axially relatively long and radially relatively thick outer rings and axially relatively short and radially relatively thin inner rings.

Abstract: An electrical sleeve heater has an inner tube centered on an axis and formed with an axially extending and radially inwardly open cutout open at an axial end of the tube, an electrical heater coil wound around the tube, an outer tube engaged around the heater coil and tube, and an axially elongated thermal sensor probe having a sleeve and a pair of wires extending axially in the sleeve fitted in the cutout. The inner tube has substantially cylindrical inner and outer surfaces and the thermal sensor probe has a radial thickness smaller than a radial distance between the inner and outer surfaces.

Abstract: An electrical heater for a mold has an elongated tubular casing made of a ductile metal and deformable by hand, a manually deformable electrical heating element extending longitudinally inside the casing, and a manually deformable mass of electrically insulating potting filling the casing around the element. The casing can be annularly corrugated and formed by a succession of like U-section rings each having a pair of parallel legs and a bight portion and a succession of like rounded annular webs interconnecting the rings and each joining a leg of one respective ring with a leg of an adjacent respective ring.

Abstract: A sleeve heater is made by first cutting in one face of a flat metal plate a continuous groove and then fitting to the groove a heater wire with at least one end of the wire projecting past an edge of the plate. The plate is then plastically deformed with the wire to a tubular shape centered on an axis with the one face directed radially inward. The installation on a body to be heated is completed by fitting the deformed plate over the body to be heated and tightening the plate on the body to grip it snugly. The plate is formed of a heat-conducting metal, for instance brass, copper, or aluminum. The face of the plate from which the wire projects is directed radially inward so the wire directly engages the body. The tightener, which can be a band that circumferentially surrounds the sleeve or fittings provided at edges of the sleeve, bridges edges of the plate.

Abstract: An electrical sleeve heater has a tubular outer wall and a heating coil inside the outer wall. An outer sleeve inside the heating coil formed with an axially throughgoing slot having angularly confronting edges is made of a material having a high coefficient of thermal expansion. An inner sleeve inside the outer sleeve is formed with an axially throughgoing slot and with outwardly projecting lips engaged through the outer-sleeve slot bearing angularly on the outer-sleeve slot edges. It is made of a material having a low coefficient of thermal expansion so that when the sleeves are heated the outer-sleeve edges press the inner-sleeve lips together and thereby decrease the radial inner diameter of the inner sleeve.

Abstract: An electrical heater for heating an object having a generally cylindrical outer surface has a helicoidal coil having a plurality of turns centered on an axis and inner and outer ends and adapted to fit around the object in contact with the outer surface thereof. A source of electricity is connected to the inner end for supplying electricity thereto and thereby heating the coil. An anchor fixed on one of the turns adjacent the outer end is connected to an element extending to the anchor for drawing the outer end and anchor together and thereby reducing an inside diameter of at least an outer turn of the coil and tightening the outer turn around the object around which the coil is fitted.

Abstract: A die-casting apparatus has a pair of mold parts together defining a mold cavity and a feed sleeve set in one of the parts and defining a passage having a short inner portion opening into and flared toward the cavity, a long outer portion of uniform cross-sectional shape and having an outer end, and a restriction between the portions. Molten metal is fed to the outer end and through the passage to the cavity. A heater surrounds the sleeve at the outer portion for heating the sleeve substantially only at the outer portion and insulation surrounds the heater. The sleeve and any metal therein are cooled at a location in the sleeve downstream of the passage outer portion, normally at the restriction.

Abstract: A sleeve heater has a pair of end tubes centered on a common axis and having axially confronting and spaced inner ends, an electrically resistive helicoidal heating coil centered on the axis, and at least one tubular center tube coupled to the end tubes at the inner ends thereof and axially and angularly slidable on at least one of the end tubes so that the length of the heater can be adjusted. The coil has a pair of end sections of relatively shallow pitch in the end tubes and a center section of relatively steep pitch between the inner ends. Thus with this system the user can alter the length of the sleeve heater.

Abstract: A heater used on a body having a substantially cylindrical outer surface has a heatable generally cylindrical sleeve fittable over the body and having one end formed with a screwthread and a ring threadable into the screwthread locks the sleeve on the body. More particularly the ring is also formed with a screwthread complementary to the body screwthread and both screwthreads are tapered. This ring is split along its full length so that when the ring is screwed into the body it is compressed radially of a central axis of the body.

Abstract: A nozzle for an injection-molding machine has an elongated body centered on an axis and formed with an axially and longitudinally throughgoing passage, a threaded rear end, an outer wall, and a front end formed with a step having an axially forwardly directed annular face and a radially outwardly directed annular side surface set in from the outer wall. A removable nozzle element is set in the passage at the front end and an electrical heating element is provided on the outer wall. A protective sleeve coaxial with the body surrounds and encloses the body and heating element and has a front end at the body front end. An end ring set on the step has an inner periphery juxtaposed with the annular surface and an outer periphery juxtaposed with the sleeve front end. Respective inner and outer annular weld joints between the inner periphery and the annular surface and between the outer periphery and the sleeve front end secure the end ring in place.

Abstract: A heating and cooling jacket for the distributor of a injection-molding machine comprises tubular inner and outer sleeves and possibly an intermediate sleeve which defines compartments filled with a high-density particle compacted mass around the cooling tube turns which hug the inner sleeve and electric heater turns which hug the intermediate sleeve.

Abstract: A heating-cartridge assembly has a shell, a first rigid insulating body in the shell having a longitudinally directed end face, a heating conductor imbedded in the body and having a pair of ends, and respective highly conductive and stiff wires imbedded in the body, connected to the ends, and having uninsulated wire ends spaced transversely from each other and projecting longitudinally from the face of the body. A second rigid insulating body independent of the first body and having a respective face is provided with a pair of imbedded and highly conductive tubular sockets having outer ends exposed at the second-body face and inner ends and lying parallel to each other at the same transverse spacing as the projecting uninsulated wire ends. These projecting stiff wires are complementarily and snugly engageable in the tubular sockets with the faces of the two insulating bodies abutting longitudinally. Respective feed conductors are connected to the inner ends of the tubular sockets.

Abstract: An electrical heating cartridge comprises a jacket, preferably of metal, at least one electrical heating coil and a thermocouple element positioned in the jacket which are imbedded with clearance from each other and from the jacket in a specially packed insulating material, wherein the electrical lead conductors of each of the electrical heating coils and the thermocouple element are guided out of a first end piece of the electrical heating cartridge. So that a rapid, controlled, uniform heating of the entire length of the cartridge is attainable, at least one electrical heating coil is directed toward a second end piece opposite to the first end piece of the cartridge and extended over and beyond the thermocouple element until adjacent the second end piece.

Abstract: A cartridge heater includes an inner casing in which a heating element is accommodated. This inner casing is surrounded by an coaxially arranged outer casing of larger diameter so that an annular space is defined between the inner and outer casings. In the space a helical coolant piping is arranged, embedded in a highly heat-conductive substance of granular and/or pulverulent form so as to allow excess heat to be carried away.

Abstract: Elecric cartridge heater having an electric heating conductor in a metallic casing and held on a support of insulating material, each of the ends of the conductor being connected with a lead of lesser electrical resistance than the heating conductor and extending through the open end of the casing the opposite end of which is closed and the conductors being electrically insulated from the heating conductor. The insulating material, preferably magnesium oxide, fills the casing and is present between the casing and the heating conductor and being compacted by diametric reduction or compression of the casing.