Set Of Rollers Research Articles

Causes of Microslip in a Continuously Variable Transmission

The continuously variable transmission (CVT) is a type of transmission that can adopt any arbitrary gear ratio. Whereas typical transmissions utilize toothed gears, the CVT employs a sphere in rolling contact with a set of rollers; loads applied to the CVT are supported across these rolling contacts, resulting in microslips of varying amounts at each contact area. In this paper, we describe the causes of microslips in the CVT and ways to lessen them through an alternative CVT design.

Comparative Study on Machining the Internal Stationary Toroidal Gear

The toroidal drive offers the advantages such as a high horsepower-to-weight ratio, coaxial configurations, compactness and high operating efficiencies. It combines most of the positive attributes of a circular worm-gear drive and epicycle gear drive without their negative aspects due to the introduction of a set of rollers in meshing contact with rolling movement between a sun-worm and planet worm-gears, and between a stationary internal toroidal gear and planet worm-gears. However difficulties were encountered in machining the toroidal surface of the stationary internal toroidal tooth profile. This paper investigates the toroidal meshing surface and develops a mathematical modelling of the meshing surface and the conjugate surface using motion analysis of the epicyclic gear train. Then the enveloping and NC machining methods are proposed and based on these machining methods the stationary internal toroidal gear is manufactured. This results the comparative study of the tooth profile of manufactured toroidal gears by the proposed methods.

Muscle oxygenation trends after tapering in trained cyclists

BackgroundThis study examined muscle deoxygenation trends before and after a 7-day taper using non-invasive near infrared spectroscopy (NIRS).MethodsEleven cyclists performed an incremental cycle ergometer test to determine maximal oxygen consumption (VO2max = 4.68 ± 0.57 L·min-1) prior to the study, and then completed two or three high intensity (85–90% VO2max) taper protocols after being randomly assigned to a taper group: T30 (n = 5), T50 (n = 5), or T80 (n = 5) [30%, 50%, 80% reduction in training volume, respectively]. Physiological measurements were recorded during a simulated 20 km time trials (20TT) performed on a set of wind-loaded rollers.Results and DiscussionThe results showed that the physiological variables of oxygen consumption (VO2), carbon dioxide (VCO2) and heart rate (HR) were not significantly different after tapering, except for a decreased ventilatory equivalent for oxygen (VE/VO2) in T50 (p ≤ 0.05). However, during the 20TT muscle deoxygenation measured continuously in the vastus medialis was significantly lower (-749 ± 324 vs. -1140 ± 465 mV) in T50 after tapering, which was concomitant with a 4.53% improvement (p = 0.057) in 20TT performance time, and a 0.18 L·min-1 (4.5%) increase in VO2. Furthermore, when changes in performance time and tissue deoxygenation (post- minus pre-taper) were plotted (n = 11), a moderately high correlation was found (r = 0.82).ConclusionIt was concluded that changes in simulated 20TT performance appeared to be related, in part, to changes in muscle deoxygenation following tapering, and that NIRS can be used effectively to monitor muscle deoxygenation during a taper period.

Improvements to the wet spinning of flax: Part I – the effect of two sets of feed rollers on the physical characteristics of wet spun linen yarns

This paper investigates the influence of the two sets of feed rollers prior to roller drafting on the physical properties of wet spun linen yarns, such as tensile properties and yarn regularity. The effect of using either a single or double set of feed rollers on the fibre fineness distribution of bleached rove was quantified using the Sirolan TM Laserscan system and reported in terms of mean fibre fineness and percentage of fibre having a diameter above 30.5 microns. Comparative spinning trials using either one or two sets of in-line feed rollers were undertaken with several batches of bleached rove. The effect of spinning parameters on tensile and regularity characteristics of the spun yarns are reported and discussed. The effect of open reach as control parameter in double feed roller spinning was also investigated. Wet spun linen yarns produced via the double crushing of bleached rove with two sets of consecutive feed rollers have a higher mean tenacity than the traditional single roller feed system.

A continuous folding process for sheet materials

In this paper, we present a new and innovative sheet material folding technology and the associated advances in folding different patterns using continuous manufacturing techniques. A novel approach is developed for the continuous folding process where sheet material is progressively folded in two dimensions, through a set of rollers, followed by a configured roller for the final folding in the third dimension. The final roller can be designed for longitudinal folding, cross-folding and angular folding to produce the desired folded pattern. This process is more economical than the traditional forming processes. An application of this process to the production of impact energy absorption structures is presented.

2739 長軸ゴムローラによる摩擦駆動特性と紙搬送特性に関する研究

In this paper, we present a friction drive and a paper transportation characteristics of a long rubber-layered roller. Deformation of the rubber-layered roller in the axial plane are calculated with the Boundary Element Method (BEM) at fifty sections of the roller considering deformation of the steel core of the roller that is calculated with Finite Element Method (FEM). Calculated static pressure between the rubber-layered roller and the steel roller agrees well with experimental one if hardness of rubber is Hs69°. A friction drive characteristic of the rubber-layered roller and the steel roller is investigated numerically and experimentally. It is shown that if we assume certain loading torque on the steel roller, the velocity of the steel roller can be predicted by the numerical simulation. Moreover, a paper transportation characteristic of a set of rollers is investigated. The values of measured paper velocity spread widely because of the fractuation of the rotation velocity of the driving motor, however, their average agrees well with the predicted one.

Role of the Unperturbed Limb and Arms in the Reactive Recovery Response to an Unexpected Slip During Locomotion

Understanding reactive recovery responses to slipping is fundamental in falls research and prevention. The primary purpose of this study was to investigate the role of the unperturbed limb and arms in the reactive recovery response to an unexpected slip. Ten healthy, young adults participated in this experiment in which an unexpected slip was induced by a set of steel free-wheeling rollers. Surface electromyography (EMG) data were collected from the unperturbed limb (i.e., the swing limb) rectus femoris, biceps femoris, tibialis anterior, and the medial head of gastrocnemius, and bilateral gluteus medius, erector spinae, and deltoids. Kinematic data were also collected by an optical imaging system to monitor limb trajectories. The first slip response was significantly different from the subsequent recovery responses to the unexpected slips, with an identifiable reactive recovery response and no proactive changes in EMG patterns. The muscles of the unperturbed limb, upper body, and arms were recruited at the same latency as those previously found for the perturbed limb. The arm elevation strategies assisted in shifting the center of mass forward after it was posteriorly displaced with the slip, while the unperturbed limb musculature demonstrated an extensor strategy supporting the observed lowering of the limb to briefly touch the ground to widen the base of support and to increase stability. Evidently a dynamic multilimb coordinated strategy is employed by the CNS to control and coordinate the upper and lower limbs in reactive recovery responses to unexpected slips during locomotion.

Advanced wound care materials: developing an alginate fibre containing branan ferulate.

This laboratory-based study set out to establish whether branan ferulate--a polysaccharide compound available in gels such as as Sterigel (SSL International, UK)--could be successfully added to the fibre of an alginate dressing to provide a superior wound-care dressing. A wet extruder (Howden Engineering Services, UK) was used to produce the fibres. Researchers examined the effect of spinning-bath calcium chloride concentration (used as the coagulant in the fibre-spinning process) on the tensile and absorption properties of alginate fibres containing 25% w/w branan ferulate. Sodium alginate and branan ferulate were separately dissolved in de-ionised water and then stirred together to make up a 5% dope solution. The dope was then forced through a spinneret and into the calcium chloride bath, where fibres were precipitated and then carried over the first set of rollers. The fibres were washed in the next bath and drawn at different rates to enhance their tensile properties. At the 'winding-up' stage the filaments were either passed over a contact heater and into a furnace (dry pick-up) or transferred into acetone baths of increasing concentrations of 50, 80 and 100% aqueous acetate to remove the water (wet pick-up). The moisture content of standard alginate fibres and those with branan ferulate were measured and compared. Breaking load, tenacity and breaking extension, and the quantity of branan ferulate in the fibres were also measured. The process was repeated four times, using different strengths of calcium chloride. Using various draw ratios, the effects of liquid uptake were measured using water, saline and a solution called A (to mimic human blood and exudate-type fluids). Out of the four calcium chloride concentrations used, 1% concentration appeared to give the highest and most conclusive results for fibre-breaking load, tenacity and breaking extension. A 1% w/v concentration of calcium chloride provides the optimum conditions for achieving suitably strong fibres with adequate absorption capacity, while allowing the least branan ferulate loss during wash and post-production treatments. In a laboratory setting the product showed promise. Research is now needed in a clinical setting and for comparison with existing wound-care products.

EFFECTS OF TRAINING AND TAPER ON MUSCLE OXYGENATION DURING 20 KM (20TT) TIME TRIALS.

648 Near Infrared Spectroscopy (NIRS) was used to measure muscle oxygenation(absorbency) changes following training and taper. Eight male cyclists(˙VO2max=4.33±0.61 L·min-1) performed simulated 20TT on a set of wind-loaded rollers before (BT) and after training(AT) (60min x 4d/wk x 3wk @ 90%HRmax) and 3 taper (T30, T50, T80) protocols. Tissue absorbency (Hb/Mb-O2) was recorded in the vastus medialis during exercise and recovery using NIRS with computer interface. Respiratory measures, HR and RPE were recorded at 5km intervals. Time to complete the 20TT improved by 50 sec but was not statistically significant. Although the 20TT's were performed at 92-94% ˙VO2max, only HR was significantly higher after taper. 20TT results showed a similar trend in deoxygenation BT and AT with a rapid decrease in absorbency during the initial 2-4 km, followed by a gradual decline to 20km. Absorbency (mV) AT (-674±342) was significantly lower than BT (-418±134), suggesting a greater degree of deoxygenation after training. However, individual plots revealed a different response in Hb/Mb-O2 following taper depending on the protocol performed. Maximum absorbency at 20km for each taper was -732±185(T30); -957±322 (T50); -534±252 (T80). It was concluded that NIRS can be used to monitor muscle deoxygenation changes following training, and, can be used to discern changes in deoxygenation with different taper protocols.

Validity of Breathing Frequency to Monitor Exercise Intensity in Trained Cyclists

This study compared breathing frequency (fB) during a ventilation threshold (VT) test with fB during a simulated 40 km time trial (40TT) to assess whether fB can be used to monitor exercise intensity. Twenty-six male cyclists (mean +/- SD VO2max = 4.42 +/- 0274 l.min-1) performed an incremental VT ergometer test and a simulated 40TT on a set of wind-loaded rollers. During the 40TT, expired gas was collected for 3 min using open circuit spirometry at 10 km intervals. A significant correlation (r = 0.89; p < or = 0.05) was found between the fB threshold (VTf) and the gas exchange VT (VTg) (3.42 +/- 0.08 and 3.31 +/- 0.09 l.min-1, respectively). No differences were found in VO2 at the VTf vs. X VO2 (3.48 +/- 0.08 l.min-1) during the simulated 40TT. However, when fB in br.min-1 calculated from the VT test (32.5 br.min-1), was compared with fB during the 40TT (45.6 br.min-1), there was a significant difference. Ventilation, heart rate and the respiratory exchange ratio were all significantly higher during the 40TT. Although a significant relationship was found between the VT test and the 40TT for VTf measured in l.min-1 of VO2 (r = 0.66; p < or = 0.05), fB in br.min-1 obtained from the incremental test should not be used to identify exercise training intensity. These data suggest that during competition, trained athletes exercise at a higher fB than that determined when being tested, implying that fB in br.min-1 may not be a valid measurement of exercise intensity.

The Elastic-Dynamic Modeling of a Press Feed Mechanism

The development of a mathematical model, describing the elastic-dynamic response of an industrial lever type roll feed mechanism, is presented. This device, which is used in all manner of powerpress work, consists of an RSSR linkage with a bent coupler, an indexing-type sprag clutch, a set of feed and pressure rollers, which move a metal strip into a die, and a disc brake. Its intermittent motion has been characterized by four motion regimes. While the spatial coupler link is considered to have distributed mass and electricity, the clutch model neglects the masses of the sprags and represents the total clutch elasticity by way of a single, nonlinear, massless torsional spring. The derivation of the equations of motion of the coupler and the feed-roller driven metal strip, for the various regimes, is based on Hamilton’s principle. The subsequent application of the method of Kantorovich, wherein the space portions of the coupler motion are expressed in terms of its in and out-of-plane free-vibration modes, makes it possible to obtain coupled ordinary differential equations for the feed-roller motion, as well as the time portions of the coupler deflections.

Reliability of peak physiological responses during wheelchair ergometry in persons with spinal cord injury.

This study examined the test-retest reliability of peak physiological responses during wheelchair ergometry (WE) in individuals with spinal cord injury (SCI). Seven wheelchair dependent subjects, two with paraplegia (T10-11 and T11-12 lesions) and five with quadriplegia (all with C6-7 lesions), were given two incremental exercise tests to volitional fatigue on separate occasions within a one-week period. Each subject wheeled his or her personal wheelchair, which was mounted on a set of frictionless rollers with side-mounted flywheels. Metabolic and cardiorespiratory responses were continuously monitored by means of an automated metabolic measurement cart interfaced with an electrocardiograph. Statistical analysis revealed no significant differences (p greater than .05) between the mean values of the two test trials for six peak values. Reliability coefficients (p less than .01) were: oxygen uptake (0.98), heart rate (0.97), ventilation volume (0.96), respiratory exchange ratio (0.91), oxygen pulse (0.96), and ventilatory equivalent for oxygen (0.88). The investigators concluded that these six physiological responses in subjects with SCI undergoing WE are highly reliable, and that these variables can be used in the objective prescription, monitoring, and evaluation of exercise rehabilitation programs for individuals with SCI.

Dynamic Measurements of Mechanical Errors in Sliver-drawing

An investigation is reported in which the lifts of the roller necks of the upper of each of the sets of drafting rollers in a drawframe were measured. Data expressed in the frequency domain showed that roller errors could be clearly seen at the fundamental frequencies of the various rollers when the error and the measurements related to the same set of rollers. Some harmonics were also visible. When errors were in one set of rollers and the measurements were made down the fibre-flow line, the sharpness of the peaks was greatly reduced by drafting waves in the fibres flowing through the system. It was deduced that drafting waves dispersed the singular frequencies produced. An absolute encoder was used on a bottom roller to average out asynchronous signal components and random errors. The averaged data demonstrated the roller shape under dynamic conditions even when the error was small. It was possible to use a ratio technique to produce a virtual encoder for the top roller. At start-up, the viscoelastic properties of the rubber covering, the distance apart of the rollers, and the error levels changed as the rubber warmed up. The dynamic shape of the roller could be determined, and the result was repeatable.

Determination of breakage parameters and modelling of coal breakage in the Szego mill

The Szego mill is a planetary ring-roller mill which is limited to continuous grinding operations and has a fast rate of material breakage. Hence, breakage parameters, S the selection function and B the cumulative breakage function for Pittsburgh coal, were determined utilizing new experimental techniques. To determine S, a steady-state, multi-pass grinding operation was utilized. It essentially involves finding the weight fraction of the top size-interval remaining in the product after each pass through the mill. Using the residence time distribution in the mill, S and its relationship with particle size were determined at various operating conditions. S is found to increase with increase in rotational speed of the mill, and the absolute rate of breakage decreases with increase in feed rate. Primary breakage in the mill was investigated by replacing the set of rollers by a single, short roller. With accurately prepared √2 size intervals, the B-values of various size-intervals were determined at different operating conditions and were found to be nearly normalizable. Introducing the experimentally determined breakage parameters in a population balance model for multi-pass grinding in the mill, product size distributions were predicted. The predicted distributions fit the experimental values very well at a low rotational speed; at higher rotational speeds, there is some deviation, caused by briquetting of very fine particles into larger agglomerates.

Low noise burster

A burster for separating successive sheets of paper from a continuous web of paper has at least one output or draw roller having a larger diameter than the input or feed rollers with all of these rollers rotated at the same r.p.m. and a simple belt drive mounted on a pivotal double link with a one-to-one ratio provides for driving one set of rollers from the other set with an adjustable distance between sets of rollers.

The preparation of cheese curd by a continuous method: the effect of heating the curd in the absence of whey

SummaryCurd was made in a continuous curd-making apparatus (Berridge &amp; Scurlock, 1969) and immediately separated from its whey. Its temperature was maintained at a high level (41–48 °C) as it was moved continuously in the form of a thin layer through a set of rollers. The curd then had a moisture content similar to that of normal curd at the end of scalding in the traditional process. After a suitable period of cheddaring the pH value and the moisture content of the continuously made curd were the same as those normally reached at the same stage in the traditional process.