Cam based Infinitely Variable Transmission Theoretic Modelling

Infinitely variable transmission (IVT) is a system which delivers the ratio between two turning elements to a continuous (non-discrete) variation (including zero). This article uses Solidworks software to build and simulate a cam-based IVT system. There are two identical units in the system under examination. Each unit comprises a cam with an oscillating slot connection that swings on a hinge and can be vertically shifted by changing the transmission rate. This modifier can be a power screw or a hydraulic ram. In addition, a grooved wheel and followers or an actuator are included in the system units. The raised wheels swing rotating movement, such that they are coupled by a single-way clutch to the output shaft (ratchet) to move the output shaft one way. During the performance research, cam shapes are considered and examined inside the mechanism. a mixture of the unchanging speed and 1-5 polynomial shapes, used for the current investigation and tailored for The results produced from the simulation generally reveal the theoretical results expected in accordance with the layout of the current IVT system. For all parts in these units, the findings imply a uniform velocity while each unit is powered. In this investigation, nevertheless, the ratchets used cause remarkable fluctuations in the angular speed of the output axis. Further research is therefore urgently needed in the choice and investigation of more efficient ratchets.

Comparative investigation of carbon fiber filaments in off-axis transverse cutting between flexible-support and non-support method under pre-tension

Short carbon fiber is an effective and essential reinforced material in composite domains. Generally, it is produced by chopping technology, among which pressing roller and grooved wheel are two popular chopping techniques. According to the working principle of these two techniques, the pressing roller can be simplified as a flexible-support cutting in off-axis transverse cutting, meanwhile the grooved wheel can be represented by a non-support cutting. To reveal the fracture difference of carbon fiber between the pressing roller and the grooved wheel technique, comparative investigation of failure behavior between a single carbon fiber (also simplified as a filament) with flexible support and with non-support was performed in off-axis transverse cutting using a custom-designed fixture. Both the cutting force and the fracture surface of the filament were comparatively analyzed in cutting process. It was found that the failure of single carbon fiber was caused by tensile effect in a non-support cutting, whereas that in a flexible-support cutting was caused by bending effect. The cutting-off force and cutting-off depth of filament cut by use flexible support are significantly lower than that by use non-support under low pre-tension. It is interesting to find out that the failure spot of carbon fiber filament in non-support cutting under low pre-tension tends to occur randomly. Meanwhile, in a flexible-support cutting, the break point of carbon fiber filament is determined by the tip of the blade. After a comprehensive comparison, the flexible-support cutting is a prior selection to produce short carbon fibers compared with the non-support cutting.

Effect of Texturing on the Friction Characteristic of Carbide and Steel Material by Grinding Process

In this paper, friction behavior of textured carbide and steel surface has been studied in order to investigate the effect of different patterns. Several simple textures have been fabricated using straight groove grinding wheel. By microstructuring, various spacing and height of the structure, we investigate the role of topography in terms of friction characteristic. The change of friction behavior has been tailored by grinding operation using straight grooved wheel and evaluated in terms of friction. Friction values were measured by Tribometer. Frictional properties of textured carbide and steel surfaces were assessed with the help of parallel steel slider with 2000g normal force under dry condition using four different sliding speeds. It is found from the experiment that except 30° and 90° angle patterns, rest of the patterns on carbide surfaces show friction reduction which is roughly from 0.15 to 0.13. On the other hand, similar textured patterns can reduce the COF from 0.17 to 0.13 in case of steel surface.

Torus Structure and Development in the Woods of Ulmus Alata Michx., Celtis Laevigata Willd., and Celtis Occidentalis L.

Pit membranes between tracheary elements of Ulmus alata, Celtis laevigata, and Celtis occidentalis often contained tori. The degree of development of tori varied and was greatest in those membranes connecting elements of small diameter. Complete tori consisted of two wall thickenings adjoined by a central layer. In three dimensions the shape of the torus often approximated a grooved wheel. Initiation of thickening in the pit membrane occurred first on the side of the older cell and was well underway prior to the beginning of secondary wall synthesis. Torus formation resulted from the thickening of the primary walls of the pit membrane. Development of the torus was associated with membranous vesicles and cisternae but not with microtubule complexes as was reported in Osmanthus. The pit membranes in this study are capable of aspiration, and the tori may prevent rupture of the pit membrane during this process.

A Method for Reducing the Corner Wear in Plunge Grinding

There are many cylindrical grinding operations like crankshaft grinding in which the corner radius is critical and hence, the corner wear is important. Studies with a patented side-grooved wheel have shown a remarkable improvement in the performance of the wheel. With the side-grooved wheel, there was reasonable reduction in grinding forces, wheel corner wear and glazing tendencies. This paper deals with a detailed investigation on the performance of side-grooved wheels in cylindrical plunge grinding applications.

II. Contributions to terrestrial magnetism. — No. III

In the present number of these Contributions, I propose to give an account of the observations on the magnetic intensity made at sea by the officers of Her Majesty’s ships Erebus and Terror, on their passage from England to Kerguelen Island, the unreduced observations, transmitted to the Admiralty by the Commanders, Captains Ross and Crozier, having been placed in my hands for that purpose. They will be divided for convenience into two sections, viz. 5. Observations between England and the Cape of Good Hope . 6. Observations between the Cape of Good Hope and Kerguelen Island . 5. Observations between England and the Cape of Good Hope . The observations in the Erebus were made by the statical method devised by Mr. Fox, with one of his instruments of 7½ inches diameter. The intensities were measured by the angles of deflection produced, in different localities, by a constant weight applied to a grooved wheel on the axle of the needle; and the ratio of the intensities is inversely as the sines of the angles of deflection, subject to a correction for differences of temperature of the needle, computed by the formula ⋅00016 I' ( t ' — t ), in which t is the standard and t ' the observed temperature in degrees of Fahrenheit, ⋅00016 a coefficient determined experimentally by Mr. Fox, and I' the observed intensity. At sea, where the manipulation of the weights causes an exposure of the needle, which, in bad weather particularly, is liable to occasion injury, the plan recommended by Mr. Fox, of using deflecting magnets instead of weights, was frequently resorted to. In this case the ratio of the intensity in different localities is inversely as the sines of the angles of deflection, and directly as the weights equivalent to the deflecting force of the deflector on the needle at the respective angles; or I' = I. w' / w ⋅ sin v /sin v' where I, v , and w are the intensity, angle of deflection, and equivalent weight at a base station; and I', v' and w' corresponding values at another station. A table is usually formed for each instrument experimentally, under Mr. Fox’s own direction, of the equivalent, or as they are termed by him, the coercing weights, for each deflector on each of the needles at the different angles which are likely to occur in the course of the observations. This is done by placing the deflector successively at angles from the dip, each differing one degree from the preceding; the needle is thereby deflected to a smaller angle on the side of the dip opposite to the deflector, and is brought back to the dip by a weight applied to the grooved wheel on the axle; this weight is called the coercing weight corresponding to the angle from the dip at which the deflector was placed. For greater accuracy, the table is formed from results obtained by placing the deflector successively on either side of the needle. Owing to accidental circumstances, no table of this description was prepared for this instrument before the Expedition sailed; the pressure of other duties prevented its being done at St. Helena, the Cape of Good Hope, or at Kerguelen Island; and at Van Diemen Island the end of the axle of the needle being accidentally broken, the needle was returned to England to be repaired, and was thus separated from the instrument and from the deflectors. Under these circumstances we have no other resource for reducing the observations made with the deflectors, than to form a table from the observations of the weights and deflectors (when both methods have been employed at the same station), which shall answer the same purpose as a table of coercing weights. Fortunately the number of such stations is considerable.