Showing papers on "Bend radius published in 1977"

Low‐loss optical transmission through bent hollow metal waveguides

Abstract: The transmission of 10.6‐μm light in bent metal‐walled waveguides of rectangular cross section is described both theoretically and experimentally. It is shown that the bending loss per angle of bend in these waveguides is explicitly independent of waveguide height, bend radius, and light wavelength, depending only on the reflectivity of the waveguide walls. In confirming experiments, guides with aluminum walls showed 95% transmission per radian of bend for radii in the range from less than 1 cm to 1 m.

Overlength light wave conductor storage system - has hollow cylinder whose dia. is double min. bending radius of conductor

Abstract: The storage system for overlength light-wave conductors operates by looping the conductor wires within cable sleeves whereby the wires have een joined by splicing elements. A carrier plate (1) has cable holding units (6) and operates with a splicing comb (3) and guides (4) for the light-conducting wires. A marking unit (7) in the form of a hollow cylinder provides control over the bending so as to ensure that the permissible bending radius of the wires is not exceeded. The dia. of the cylinder is double the min. permissible beinding radius. Use of the system enables the relatively fragile light conductors to be stored without danger of them fracturing.

Retractable pressure die

Abstract: In a machine for draw bending pipe, a long pressure die that moves with the pipe during the bend is provided with a retractable rear section. Both sections are used for a large degree of bend but when a bend of lesser degree is made near the end of the pipe, interference between the pipe grasping chuck and the long pressure die is avoided by retracting the rear pressure die section.

Process for bending metal sheet

Abstract: A process for bending on a press a metal sheet through a desired angle and an inner bend radius less than the thickness of the sheet, without causing damages such as cracking in a bend. According to this process, a metal sheet is first bent through an angle approximating a desired angle, with an inner bend radius being greater than the thickness of the metal sheet, and then the metal sheet thus bent is further bent through a desired angle, with the inner bend radius being less than the thickness of the metal sheet, and with the stretching of a material of the metal sheet on the outer side of the bend being suppressed.

A multifilamentary Nb 3 Sn dipole magnet

Abstract: A one meter long, 8 cm aperture dipole magnet has been constructed from prereacted Nb 3 Sn multifilamentary conductor. The conductor is in the form of a wide braid formed from 95 wires of 0.3 mm dia. each containing 1045 filaments of niobium in a copper-tin matrix. After braiding and compacting the conductor was heat treated to form the Nb 3 Sn filaments. The braid was then wound into a dipole of the ISA type using techniques similar to those employed in the construction of magnets from the more conventional NbTi braid. Voltage taps were attached to the conductor at appropriate positions so that the effect of mechanical stress could be observed at the bends of greatest curvature. The effective resistivity of the bent regions of the conductor showed a marked dependance on the bend radius varying from 7 × 10-10ohm-cm at a radius of 0.6 cm to approx, 10-10ohm-cm at 1.0 cm measured at a field of 3 T and a current density of 3.7 × 104Amps/cm2. While the bending of the conductor during coil fabrication did lead to some damage of the Nb 3 Sn filaments, it was not the factor limiting coil performance. The connection between the coil halves in the magnet was resistive and limited the maximum coil current to 2650 amps, well below the short sample limit. An improved method of coil interconnection is being used in future magnets in this series and should make it possible to extend the measurements to higher fields and current densities.

Radiation from a circular bend between two discontinuities in surface waveguiding structures

Abstract: Surface waveguides radiate energy at bends. The asymptotic problem of solving for the radiated power and the radiation pattern for large radius of bend has been studied theoretically for the slab waveguide and for the circular cylindrical waveguide. The slab configuration consists of two semi-infinite slabs joined by a circular bend. The cylindrical configuration consists of two straight circular cylinders joined by a circular bend. The results indicate that the discontinuities at the transitions between the straight sections and the bend cause the radiation to differ significantly from the radiation of a bend of the same size but being part of a uniform circular structure rather than being joined to two straight sections. The radiated power for both the slab and circular cylinder configurations is found to vary inversely as the square of the radius of curvature, and the radiation pattern is composed of many closely spaced narrow lobes. As the radius of curvature of the bend increases, the lobes become more numerous and more closely spaced.

Form tool for producing curved duct sections - forces duct into ring gap between core and tool body

Abstract: A sheet metal duct (61) which has a circular cross section is bent to form an elbow joint up to 90 deg. A press tool (60) which can be split open, has a built up core (66-68) so that a ring chamber (69) in the shape of the finished duct bend is obtained. The initially straight duct section has one end face at an incline to compensate the unequal metal flow during the forming operation. A hydraulically operated piston (71) forces the straight duct into the ring gap between form tool and cores. A material flow, similar to that on an extrusion process is obtained. It is thus possible to produce duct bends of very small bending radius.

Pipe bending unit - for hot bending large diameter pipes with hydraulic press device for minimising cross-section deformation

Abstract: In the hot bending of a metal pipe, particularly a pipe of large diameter, whereby (i) the pipe is transported through a heating device e.g. a high frequency induction heater, which can heat a limited region to a high temperature, (ii) the front end or a suitable central part of the pipe is clamped to an arm which can pivot freely round an axis in the plane of the heating device and has a length adapted to the bending radius (iii) the pipe is subsequently transported continuously and in a straight line, while being heated locally by heating device to a temperature causing plastic deformation and being immediately thereafter cooled (iv) a binding movement is exerted on the pipe to bring about a continuous deformation in the heated zone of the pipe, the further improvement whereby (v) the pipe can be a circular metal pipe which is subjected to a compressive load on parts near the high temperature plastic zone applied on the vertical direction to the direction of compression, directly after the heating and cooling, so that the desired bending is achieved. Method permits large pipes to be bent with high accuracy and minimum flattening, kinking etc.

Bending machine for sheets or tubes - has pivot centre of forming block coinciding with centreline of bending radius

Abstract: The bending machine can be driven electrically, pneumatically or hydraulically. It consists of a clamping block attached to the machine frame. An adjustable table can be moved towards the clamping block to clamp the workpiece and a bending web. The corner of the clamping block has the same radius as the internal bending radius of the workpiece and a sloping side face which limits the angle of the bend. The clamping block can be replaced, to vary the angle and radius of the bend. The bending web can move on a slide so that it can be brought in engagement with the workpiece. The slide is mounted on a wheel which rotates about a centreline which coincides with the centreline of the bending radius of the workpiece.

A MULTIFILAMENTARY Nb3Sn Dipole Magnet

Abstract: A one meter long, 8 cm aperture dipole magnet has been constructed from prereacted Nb Sn multifilamentary conductor. The conductor is in the form of a wide braid formed from 95 wires of 0.3 mm dia. each containing 1045 filaments of niobium in a copper-tin matrix. After braiding and compacting the conductor was heat treated to form the NbgSn filaments. The braid was then wound into a dipole of the ISA type using techniques similar to those employed in the construction of magnets from the more conventional NbTi braid. Voltage taps were attached to the conductor at appropriate positions so that the effect of mechanical stress could be observed at the bends of greatest curvature. The effective resistivity of the bent regions of the conductor showed a marked dependance on the bend radius varying from 7 X ohm-cm at a radius of 0.6 cm to approx. ohm-cm at 1.0 cm measured at a field of 3 T and a current density of 3.7 x lo4 Amps/cm2. While the bending of the conductor during coil fabrication did lead to some damage of the Nb Sn filaments, it was not the factor limiting coil per- 3 formance. The connection between the coil halves in the magnet was resistive and limited the maximum coil current to 26.50 amps, well below the short sample limit. An improved method of coil interconnection is being used in future magnets in this series and should make it possible to extend the measurements to higher fields and current densities. 3

Method and apparatus for measurement of allowable bending radius of op tical glass fibers

Abstract: PURPOSE:To efficiently measure the bending characteristics of an optical galss fiber by the use of either such a cylinder as has its diameter varied steplessly and continuously or such a cone as is formed with a helical groove having its radius of carvature varied steplessly and continuously

Heat exchanger and its manufacturing method

Abstract: PURPOSE:In a heat exchanger in L type or U type, even though it is referred to a pipe at the part that the bending radius of the pipe at the bent part differs respectively, the identical length is secured for bare pipes jutted out of an extremity fins not to deteriorate the brazing workability.

Machine for bending thin walled tubes - has die and transporter with grooves varying from elliptical to circular

Abstract: The machine for pipe bending is esp. for bending thin walled pipes with circular cross sections. The pipe is placed on a rotating die with a radius corresp. to the pipe bend radius. The pipe is pressed against the die by a transporter with semielliptical grooves. The pipe is bent and deformed so that a circular pipe cross section is generated at the bend. The pipe transporter has a replaceable transition piece. The groove cross section varies in the transition piece steplessly from semielliptical shape to semicircular shape corresp. to the circular pipe section. The transition occurs within a region displaced from the initial clamping point corresp. to the required bend length.

Curvature measurement device with flexible elastic steel probe - has attached strain gauges for accurate large radius measurement

Abstract: A measurement device is for the measurement of the radius of curvature of curved or arched surfaces. It overcomes the difficulties and inaccuracies encountered with surfaces having bumps or indentations with difference measurements between surfaces of large radius where only a small sensor radial motion occurs, and non-constant sensor movement to radius variation relations. A flexible elastic measurement probe has an associated strain gauge attached to it which determines the deformation of the probe and hence the radius of curvature may be calculated. The probe is a strip of spring steel with attached electrical strain gauges whose output signals are converted into a visual display of the radius of curvature.