Abstract: A sheet metal article is formed from one or more sheet metal panels (2), each having a channel (1) pressed into one surface of the panel (2) along a bend line. The panel (2) is bent along the bend line by grasping the panel (2) on both sides of the line and manually folding the panel. To increase rigidity, the channel (1) is formed such that the rims of the channel walls (3, 4) abut each other when the panel (1) is folded. A gently radiused bend in a panel can be achieved by pressing a plurality of parallel channels in a panel in a band of width 1.57R where R is the required bend radius. Panels formed with channels in this way are suitable as components in a flat-pack kit for assembling a box-like article.

Abstract: A strain relief system for flexible circuits has a tapered cover laminate affixed to either side of the flexible circuit to form a cover laminate/flexible circuit assembly, with the widest portion of the cover laminate being at the point of maximum bending stress of the flexible circuit to provide a stiffer assembly at that point. A rigid stiffener having a bending radius also is affixed to either side of the cover laminate/flexible circuit assembly at the point of maximum bending stress to provide strain relief, the bending radii being laterally offset from each other so that bending in opposite directions occurs at different locations of the flexible circuit. The result is a gentle, low stress bend in the flexible circuit when subjected to regular bending.

Abstract: Using the momentum equation it is shown that the radial force per unit area exerted by the flow on the external bank of a circular river bend is directly proportional to a certain curvature coefficient, C. This coefficient is dependent on the ratio of bend radius (R) to flow width (w), as well as on the dynamic friction coefficient of the bedload. The variation of C with R/w shows a maximum at (R/w) 3. The rate of lateral bend migration in 16 bends of the Beatton River, Canada, was found to be well correlated with C over a range of 1.2 equal to or less than (R/w) equal to or less than 13.0. This correlation suggests that the hydraulic analysis based on the momentum equation may offer a partial explanation to the variation in the rate of channel migration with R/w, and to its maximum at (R/w) 3.

Abstract: A limited bend transmission cable for coaxial microwave cables which also has controlled movement under torque. A coaxial microwave transmission line of choice is covered by successive layers of helically-wound armor sheath, hard wire located in the groove of the sheath to aid in control of bend of the cable, a hard wire or braid, insulation, and strain relief boot.

Abstract: A device for limiting the bending radius of a submarine cable portion. The device is composed of a plurality of turbular elements (5) connected to one another in an articulated manner. Each element (5) is formed by a tubular cylindrical body (10) having two end flanges (12, 13) provided with circumferential through-holes (21, 31) for the passage of connecting members (4). One flange (12) has semi-spherical projecting members (28) in diametrically opposed positions with respect to each through-hole (21). The other flange (13) has complementary semi-spherical projecting members (28).

Abstract: This research initiates a study of the mechanics of four roll plate bending and provides a methodology to investigate the process experimentally. To carry out the research a suitable model bender was designed and constructed. The model bender was comprehensively instrumented with ten load cells, three torquemeters and a tachometer. A rudimentary analysis of the four roll pre-bending mode considered the three critical bending operations. The analysis also gave an assessment of the model bender capacity for the design stage. The analysis indicated that an increase in the coefficient of friction in the contact region of the pinch rolls and the plate would reduce the pinch resultant force required to end a plate to a particular bend radius. The mechanisms involved in the four roll plate bending process were investigated and a mathematical model evolved to determine the mechanics of four roll thin plate bending. A theoretical and experimental investigation was conducted for the bending of HP30 aluminium plates in both single and multipass bending modes. The study indicated that the multipass plate bending mechanics of the process varied according to the number of bending passes executed and the step decrement of the anticipated finished bend radius in any two successive passes (i.e. the bending route). Experimental results for single pass bending indicated that the rollers normally exert a higher bending load for the steady-continous bending with the pre-inactive side roll oper?tive. For the pre-bending mode and the steady-continous bending mode with the pre-active side roll operative, the former exerted the higher loads. The single pass results also indicated that the force on the side roll, the torque and power steadily increased as the anticipated bend radius decreased. Theoretical predictions for the plate internal resistance to accomplish finished bend radii of between 2500mm and 500mm for multipass bending HP30 aluminium plates, suggested that there was a certain bending route which would effectively optimise the bender capacity.

Abstract: PURPOSE:To prevent an optical fiber cable from being damaged by a torsion of the cable and a difference of a bend radius, by controlling a roller driving mechanism so that a tension of the optical fiber cable becomes within an allowable tension range in accordance with a detecting signal of a tension detector CONSTITUTION:A tension detector 16 is installed to a machine body frame 6 in the vicinity of the first leading-out roller 7 To the tension detector 16, a controller 20 for controlling a roller driving mechanism 9 is installed so that a tension of an optical fiber cable 2 becomes within an allowable tension range in accordance with a detecting signal When the tension of the optical fiber cable 2 becomes large in the course of a leading-out work, a dancer arm 18 is turned counterclockwise, and when said tension becomes small, said arm is turned clockwise, a turning shaft 17 is turned, the controller 20 is driven to turn and its resistance value is varied, and the tension of the optical fiber cable 2 is controlled so as to become with the allowable tension range

Abstract: A numerically-controlled bending machine for tube or rod workpieces comprises a bend head (10, 11) including a bend former (14), collet chuck means (1) for supporting a workpiece at a predetermined position and axial orientation against the bend former, and means (14, 15) for clamping the workpiece against the bend former, the bend head being operated to rotate the bend former by a rack (13) and pinion (12) arrangement, wherein the rack includes a pre-settable mechanical stop (30) to control the extent of movement of the rack and hence the extent of bend angle The required bend parameters are programmed into the control system using "user-friendly" language which is automatically convertible into CNC language for automatic control of the bending operation or sequence of bending operations

Abstract: PURPOSE: To reduce the cost in manufacturing by executing bending on the edge at both sides of a strip steel and the center part with the specified radius of curvature, executing bending on other zones with the specified magnification curvature of the max. product radius as well and executing butt welding. CONSTITUTION: At the prestage of a breakdown the bending of rolls 5, 6 is executed with the radius of curvature of 0.8W1.2 times the min. product radius R on the both sides edges 2a, 2b of a metal plate 1. In this case, the distance between the split parts of upper and lower rolls 5, 6 is adjusted via a spacer. The parts 3a, 3b of the metal plate 1 is then subjected to light bending with the radius in 1.5W10.0 times the max. product radius R and the center part 4 of the metal plate 1 is subjected to bending with the same radius as the side edges 2a, 2b. In succession the butt welding of the end edge is executed. Due to the forming being executed with less split rolls with preventing a buckling the production cost of an electric resistance welded tube is thus reduced. COPYRIGHT: (C)1988,JPO&Japio

Abstract: PURPOSE:To improve the productivity and the product accuracy by sticking a strain gauge to the same position of the surface and the rear side of a strip, also providing a slit in the peripheral direction at the corresponding position of a roll, and measuring continuously strains on the surface and the rear side of the strip. CONSTITUTION:A strain gauge 4 is stuck to the same position of the surface and the rear side of a metallic strip 1, respectively. At a position where the strain gauge 4 passes through on the surface of a roll 2 and 3, a slit 21 whose width is wider than the width of the gauge 4 is provided in the peripheral direction of the roll. Also, this slit 21 is buried by a synthetic resin, etc. of a low Young's modulus. By this measuring device, the peak strain of the time when the strip 1 passes through the rolls 2, 3 is derived, and also a radius of curvature is obtained by arithmetic. By using this bending radius of curvature, the shape is straightened based on a relation between plate thickness, tension, roll push-in quantity, etc. which are derived in advance, and the radius of curvature. According to this method, the operation is executed stably, and also the productivity and the product accuracy are improved.

Abstract: An articulating element is proposed which is preferably suitable for use in cable channel ducts and consists of a tubular piece (1) whose end (1a) is expanded in the form of a cup, into which a tubular piece (2) is pushed whose end (2a) slightly thickened corresponding to this cup-shaped expansion and tapers slightly from the inside, starting approximately in the centre of the thickening, to the outside, and of a collar ring (3) screwed or snapped over the connecting point. A stop (1b, 3b) is provided both at the transition from the tubular piece (1) to the cup-shaped expansion (1a) and on the rearward end of the collar ring (3), with which the angle of articulation is limited. The measures according to the invention ensure that there is practically no change in the internal cross-section in the region of the bend and the bending radius of the cable channel duct is not less than the minimum permitted bending radius, in order to avoid damage to the cable which is to be pulled in.

Abstract: A detailed experimental study has been made of the transmission of Ti:LiNb03 waveguide bends formed from circular arc sections. The effects of varying modal confinement and bend radius in compact areas have been identified.© (1986) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Abstract: The device makes it possible to form, for each fibre, a reserve length but in such a way that the reserve appropriate to each fibre is independent and cannot be mixed up with the other fibres housed in the device. Interleaving elements (3) are associated with a body (2) such that each forms a separating partition between two neighbouring fibres. Each interleaving element comprises a lip (19) which determines the maximum allowed limit for expansion of the length of the corresponding fibre held in reserve and a circular boss (18) whose radius corresponds to the minimum bend radius allowable by the optical fibre. The invention is applicable in the field of equipment for the videocommunication network.

Abstract: Zinc Selenide (ZnSe) infrared optical fibers 33 cm long x 1 mm in diameter have been fabricated. The measured attenuation coefficient of these fibers at 10.6 pm ranges from 0.3 dB/m to 4.0 dB/m depending on the surface quality. The minimum bend radius of a number of uncladded fibers was measured to be 73 + 8 cm. The measured transmission of uncladded fibers does not change when the fibers are bent to a radius of 115 cm. When the fibers are cladded with TFE heat shrinkable tubing, the transmission is unchanged for straight fibers. However, the attenuation of these cladded fibers increases by a factor of 1.25 when they are bent to a radius of 85 cm. The minimum bend radius of the cladded fibers is equal to that of the uncladded fibers within the uncertainty of the measurement. ZnSe can efficiently transmit radiation over a wide range of wavelengths (0.6 -14 μm). Therefore, these fibers have potential applications in catheters and endoscopes for CO 2 laser surgery, in probes for remote optical measurements of hostile environments and in various military infrared optical systems.

Abstract: Zinc Selenide (ZnSe) optical fibers 30 cm long by 1 mm in diameter have been fabricated by a grinding and polishing technique. The bulk transmission through a 30 cm length of these uncladded fibers is as high as 99 ± 2% at 10.6 pm. This corresponds to a bulk attenu-ation coefficient, a, as low as 0.2 dB/m. There appears to be no change in transmission within the uncertainty of the measurements when the fibers are bent to a radius of 115 cm. The minimum bend radius (fracture point) of the fibers was measured to be 60 ± 14 cm. As much as 14 watts of power for up to 5 min. was transmitted through the fiber without any damage or heating. Also power densities as high as 10 kW/cm2 incident on the polished input end of the fiber caused no detectable damage to the surface. ZnSe can efficiently transmit radiation over a wide range of wavelengths (0.6 - 14 μm). Therefore, these ZnSe optical fibers can transmit radiation from He:Ne, Nd, HF/DF, CO and CO2 lasers. The fabrication technique used to produce these fibers is scalable to longer lengths. Cladding techniques are currently under development. Such ZnSe fibers have potential application in catheters and endoscopes for CO2 laser surgery, probes for remote optical measurements in hostile environments,and in various military infrared optical systems.© (1986) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Abstract: PURPOSE:To prevent the decrease and flattening of the sectional area in a pipe and to maintain the smoothness on the inside circumferential surface by forming the top part to the arc surface of the same radius as the radius of the arc surface of a sacrificial plate and coupling integrally plural pieces of intermediate core segments from the part near the root toward the arc surface. CONSTITUTION:Plural pieces of the intermediate core segments 2 are positioned to the point where a straight pipe material A is bent and formed to an elbow part B in continuation with the end face in the fitting part of a core 1 in one straight part. The section thereof forms wedge-shaped slopes 2h', 2h' of the width decreasing toward the arc surface 2c with the front and rear faces connected to parallel surfaces 2h, 2h. The angle alpha between both slopes 2h' and 2h' is determined by the magnitude of the bending radius R of the elbow part B. The sacrifitial plate 4 consisting of a low melting material is provided with a fitting groove to accept the fitting pieces of the cores 1, 3 in both straight parts and the fitting pieces of the segments 2.

Abstract: Effect of adhesion strength on the Bendability was studied in a compositetype vibration-damping steel sheet which consists of two steel skins bonded with a viscoelastic resin. The adhesion strength of the damping sheet was evaluated in tensile shear strength (TSS); TSS values of the damping sheets used for the test were 6, 61, 126 and 148kgf/cm2. U-and 90 deg-bend tests were adopted as bend formability tests.It was found that the bendability of the damping sheet is closely related to their TSS, and it is improved with an increase of TSS. When the TSS is higher than 126kgf/cm2, the bendability of the damping sheet is quite similar to that of conventional steels. On the other hand, when the TSS is as low as 6kgf/cm2, the slip and peel-off between two skins were observed in the bend tests.In the 90 deg-bend test, the damping sheet with TSS of lower than 61 kgf/cm2 bend properties are different from the conventional steel. In large size of bend radius, bend angles of the damping sheet were larger than those of the conventional steel. However, in small size of bend radius, bend angles of the damping sheet were smaller than those of the conventional steel. These behaviors of the damping sheet are based by elastic property of the core resin.

Abstract: PURPOSE:To stabilize the plane face accuracy of a bend tube and to relieving the restrictions of working shape and dimension by providing the rotary shaft of an arm on the upper direction of the tube to be worked and by making the arm supporting structure a both ends support. CONSTITUTION:The tube to be bent 1 is inserted into a high frequency heating coil 3 and fixed to an arm 12 via a clamp device 13. Simultaneously with the tube wall reaching the hot work zone with the high frequency heating a coolant is sprayed on the surface from a pump 4 and the heating width is controlled by a cooling ring 5. The arm 12 setting the bend radius is rotated centering around a rotary shaft 14 with the temp. rise thereof, performing a bend work on the tube 1 fed out by a feeding device 7. In this case due to the rotary shaft 14 being of both ends support the bend work is performed irrespective of the gap of abrasion, etc. and a stable plane face accuracy is obtd. and the shape and dimension restrictions due to the installation structure of the work machine is relieved as well in case of a solid bending.

Abstract: This thesis investigates the behaviour of large air pockets forming at the junction bend of a vertical dropshaft and a horizontal or slightly inclined outlet tunnel. A secondary thrust of the work concerns the behaviour of air pockets in straight pipe sections inclined at a shallow slope both upwards and downwards from the horizontal. These aims were achieved by constructing a physical model of the situation and also by deriving theoretical models of each physical situation arising. The experimental data is compared with the derived theoretical models, and both are compared with past research in this field. The physical model was tested over a range of nine different geometries. The radius of the junction bend (R'/D) was tested at values 0.5, 1.0 and 1.5, the tunnel slope (0) was varied between +1.5, 0 and -1.5, the water flow rate was varied from 0 to 0.04 m3/s, and the air flow rate, in the form of independent injection of air bubbles down the dropshaft, was varied from 0 to 0.02 m3/s. The ultimate aims of the work were as follows: (a) to obtain a deeper understanding of air pocket behaviour at vertical bends and in straight pipes. (b) to ascertain if simplified theoretical models can be made realistic enough to describe air pocket behaviour, especially the chaotic behaviour of a two-phase flow at a dropshaft/tunnel bend. (c) to provide insight and information for the designers of such hydraulic structures. In the first chapter an introduction to air presence in Civil Engineering Hydraulic Structures is given, with reference to the benefits and problems associated with air presence and the structures which have experienced problems. A state-of-the-art review of past research work on air pockets in closed conduit hydraulic structures is given in Chapter (2). Chapter (3) is concerned with producing theoretical models for air pockets at the dropshaft/tunnel bend. This includes air pockets blowing back, air pockets with a drowned jump, air pockets with a hydraulic jump and air pockets clearing downstream from the bend. Also, theoretical models are produced for air pockets in straight pipes inclined above and below the horizontal. Chapter (4) contains a description of the design of the experimental apparatus, the instrumentation used, as well as details of the experimental procedure. Chapter (5) includes the experimental results for the behaviour of air pockets at the nine dropshaft/tunnel bend geometries tests. The experimental results for each geometry tested are presented graphically, covering the various flow regimes found to exist at the bend, the depth of air pocket forming at the bend, the upper limits of air pocket blowback up the dropshaft, the lower limits of air pocket clearing downstream from the bend, as well as information on the velocity and Froude number of flow under the air pocket forming at the bend. A comparison is carried out between the three bend radii used as well as the three angles of outlet tunnel. Chapter (6) includes the results of air pockets in straight pipes. Most of the data was obtained for air pockets rising in an upward sloping straight pipe. The design of the experimental apparatus permitted only a few data points to be taken for the case of the downward sloping straight pipe, for reasons outlined in Chapter (6). Chapter (7) contains the comparison between the theoretical models and experimental data for both air pockets at the bend and in straight pipes. Empirical equations are derived for the case of air pockets clearing downstream from the bend, where no theoretical model was attempted due to the flow complexities involved. A comparison is also carried out between the author's data and theoretical models and most of the available previous research data. Chapter (8) includes a discussion on the findings of this work, conclusions and suggestions for the future work. In the broadest terms, this work shows that four stable regimes of flow are identifiable at a dropshaft/tunnel bend and these regimes can be represented with reasonable accuracy by theoretical models of the flow, based on force-momentum and energy principles. The work also shows that the bend radius (R'/D), the outlet tunnel slope (9), the Froude number of the flow (FrO), and the ratio of air to water (B) are all important parameters affecting whether or not an air pocket will blow back, remain trapped at the bend or clear downstream. Air pocket behaviour can now be accurately predicted for the case of upward sloping straight pipes, although further work is required for the case of downward sloping straight pipes.

Abstract: PURPOSE:To perform the pipe bending having high accuracy without being influenced by the variation in heating temp. and the change in the pipe quality, etc. by controlling the locus of a clamp with using the calculated control signal by the feeding quantity of a working pipe. CONSTITUTION:A work pipe (a) is supported by supporting rolls 11a, 11b and the tip part is held by a clamp 21 and heated by a heating coil 2. When the temp. of a heating part a' is raised the work pipe (a) is fed to the arrow marked direction and the prescribed compression force is given. A pipe feeding quantity is detected by a detector 30, a pipe bending angle theta is calculated by a computing element 32, an arm rotation angle H, clamp position (l), clamp rotation angle alphaare calculated from a pipe bending radius R and pipe bending angle theta and setting signals H1, l1, alpha1 are outputted. Said setting signals H0, l0, alpha0 and actual detected signals H1, l1, alpha1 are compared by a control outputter 34 and from the deviation, the control signal 34a of the clamp driving mechanism is outputted. A rotation device 27, vibration device 25 and clamp rotation device are thus subjected to a drive control and a clamp 21 is subjected to a drive control to the prescribed locus corresponding to the pipe feeding quantity.

Abstract: A rotary compression bending machine comprises a radius die, a wiper die, and a flexible ball mandrel. Means are provided to simultaneously drive the wiper die around the radius die and to draw the ball mandrel through the tubing in order to reform the tubing while bending. The reformed tube will be wrinkle and distortion free around the bend radius.

Abstract: We present a theoretical analysis of the strain dependence of bend loss from a multimode slab dielectric waveguide formed in the shape of an arc of a circle. This dependence suggests its use as a strain gauge. We calculate the strain sensitivity of this gauge as a function of the core–cladding index difference, bend radius, and arc angle. The method that we use is a geometrical-optics analysis modified to account for the curvature of the boundary between the core and the cladding.

Abstract: This paper is the result of our research into the twisted S -shaped bend diffuser—the so-called coiled bend diffuser. It is a diffuser with a centerline in the shape of a twisted “S .” Our studies show that the performance characteristics of this bend diffuser are greatly improved when interaction by the bend elements generates an adequate secondary flow inside the diffuser. Full consideration was given to the influence of the divergent angle of the bend elements, consisting of the diffuser or curvature radius ratio of the bend, on these performance characteristics. The relation between diffuser performance and internal flow also was studied. Some guidelines for designing such a high performance diffuser is given.

Abstract: The results of an investigation into the bend loss as a function of wavelength for single-radius bends in monomode fibers are given. The fibers considered have a high numerical aperture and a protective coating which has a refractive index greater than that of the cladding. For these fibers the pure bend loss is shown to be the dominant loss mechanism over the wavelength range 633-1152 nm. In addition, oscillations in the loss are observed as the bend radius is varied at the longer wavelengths. These oscillations are shown to result from the coupling of light under weak coupling conditions from a whispering gallery mode in the cladding formed by the pure bend loss, to the fundamental mode in the core. An expression is derived which relates the bend radius at which the minima in the oscillations occur to the fiber parameters and a qualitative explanation is given for the reduction in the oscillation amplitude as the bend radius and wavelength are decreased. A criterion is identified for assessing the strength of the coupling between the whispering gallery mode and fundamental mode. Using this criterion the attenuation coefficient of the pure bend loss at which a transition from weak to strong coupling occurs is determined and is found to agree with observations. The effect of the coupling strength between the whispering gallery mode and the fundamental mode on the characteristics of the pure bend loss is discussed. Finally, possible applications arising from the results of this work are identified.