Elastic Sleeve Research Articles

Analysis of dynamic characteristics for elastic cylindrical journal bearing (1st report, Numerical analysis method)

This paper presents a numerical analysis method for static and dynamic characteristics of cylindrical journal bearings with elastic sleeves. According to the experimental result that pressure deforms a sleeve uniformly in the axial direction, elastic cylindrical bearings are modeled as thin cylinders which are uniformly deformed by the sum of pressure along the axial direction. In order to simplify the numerical analysis of the pressure distribution and deformation of the bearing, the Reynolds equation based on the average flow theory is used. It can easily include the oil film rupture effect. Since the stiffness and damping coefficients of elastic journal bearings are dependent on frequency, the Reynolds equation, equations of elastic deformation for a journal bearing and equations of motion for bearing-rotor systems must be simultaneously solved. In this paper, a new numerical method of solving these nonlinear equations with the help of the Newton-Raphson method and the Booy-Coleman method is developed to decrease computer time.

The effect of changes in muscle function and bone growth on muscle migration.

The elastic sleeve model of the periosteum of a long bone presents the periosteum as a structure which, because it is attached to the epiphyses rather than the diaphysis, expands interstitially and equally at all points as the bone grows at its ends. Structures attached to the periosteum are seen as essentially passive hitchhikers on the expanding periosteum. Two corollaries of this model are tested here. First, that changes in the magnitude or direction of the force that an attached structure exerts on the periosteum do not affect the migration of the structure. Second, that changes in the proportion of growth that occur at each end of the bone do not affect the migration of attached structures. Experiments performed on rabbits to test these corollaries include muscle paralysis, muscle transection, changes in the direction pull of a muscle, and epiphysiodesis. The results are in agreement with the hypotheses. This model should have applicability to functional and comparative anatomy, since it postulates that differences in positions of attachment of muscles and ligaments to bones reflect underlying genetic differences (phylogeny) rather than the effects of differences in behavior of the animal (ontogeny).

The prevention and management of lymphoedema after treatment for breast cancer.

Lymphoedema of the arm is a disabling complication of surgery for cancer of the breast. It occurs in a significant proportion of patients and tends to occur later after the operation. Radiation increases the incidence. It needs to be differentiated for tumour recurrence and venous obstruction. Aetiology may include surgical technique, radiation and infection. Prevention is important as treatment is difficult. Treatment may include drugs, particularly benzopyrones, and enzymes, physiotherapy, elastic sleeves and surgery.

Dynamic patellar brace: a new orthosis in the management of patellofemoral disorders. A preliminary report.

The diagnosis and treatment of patellofemoral dysfunction, especially subluxation of the patella, remains controversial. Many authors feel conservative treatment will give better long-term results than operative treatment. To aid in nonoperative treatment of patellofemoral conditions a dynamic patellar stabilizing brace has been developed. The brace applies an active, medially displacing force to the lateral border of the patella and maintains constant pressure during flexion, extension, and rotation of the knee. This brace consists of an elastic sleeve with a patellar cutout and two circumferentially wrapped "live" rubber arms which apply dynamic tension to a crescent-shaped lateral patellar pad. An elastic circumferential counterarm maintains proper positioning of the pad and prevents rotation of the brace. The brace, superior to other methods of patellar splinting, is felt to be useful in the diagnosis of suspected subluxation in patients without the classical stigmata of patellofemoral dysplasia. It has proven useful in the treatment of 39 cases of patellar subluxation and 4 of patellofemoral arthritis. In a number of cases symptoms were completely eliminated with prolonged use of the brace. The brace is felt to be beneficial in conjunction with vastus medialis rehabilitation in patellar subluxation in growing children; in patients with mild or occasional subluxation, especially during specific activities; in persons with dislocation or subluxation in which surgery is contraindicated or must be delayed; and in acute subluxation. The brace may also be helpful in the prevention and treatment of chondromalacia and patellar tendinitis.

Invariance of the relative positions of structures attached to long bones during growth: cross-sectional and longitudinal studies.

This article reports the results of cross-sectional and longitudinal studies on the positions of muscles relative to bones. The cross-sectional study reports on the positions of 20 muscles attached to long bones in the chicken from prehatching ages to maturity. The results show that these muscles maintain constant positional relationships during growth as was reported in an earlier study by the authors using rabbits. The longitudinal study reports on the migration of the semitendinosus muscle in the rabbit during growth. The results show that this muscle migrates the distance predicted by the regression equations derived from the cross-sectional study. These results are related to the model of the periosteum as an expanding elastic sleeve attached at its ends to the epiphyses and put under tension by the activity of the epiphyseal plates. In this model the soft structures attached to bones are seen as attached only to the periosteum in growing animals and thus carried along as hitchhikers by the expanding periosteum.

Total surface bearing self suspending above-knee sockets/1

A new type of above-knee socket has been designed to provide total surface support and to dispense with ischial bearing as the primary weight bearing area. The socket is based upon the hypothesis that if the soft tissues of an above-knee stump are adequately supported in a suitably shaped container they will behave under load as an elastic solid with low stiffness. A method has been devised for taking the cast for the new type socket using an elastic sleeve as a "compliant socket". The grip of the elastic sleeve and the use of traction weights deform the stump tissues to the required shape while the cast is setting. The results of laboratory measurements of the transinterface pressures in these sockets under axial loading conditions have correlated well with the figures forecast by calculation. The new socket is now available to patients at a number of Centres in England.

The Load Transfer Problem in Shafts Coupled Through a Sleeve

The following load transfer problems are considered in this paper: torque transfer between an elastic shaft and a finite elastic disk or sleeve of different materials, torque transfer between two identical shafts coupled through a finite sleeve, and torque transfer between two dissimilar shafts coupled through a finite sleeve. In all cases it is assumed that the contact between the sleeve and the shafts is one of perfect adhesion accomplished through bonding or shrink-fit. The problems are shown to reduce to singular integral equations with generalized Cauchy kernels. Some numerical examples are worked out and the stress-intensity factors and distribution of contact stresses are given.

Porcelain centrifugal pumps

The Slavyansk ce ramic combine is putting out overhung horizontal one-stage centrifugal pumps of types TsKN-M and Kh-F of ce ramics , with drive wheels of the enclosed type (Fig. 1). All parts of the pumps which come in contact with the liquid being pumped a re made of solid porcelain, a mater ia l which has high chemical res i s tance to all acids of any concentration except hydrofluoric and phosphoric, and which operates sa t isfactor i ly in weak alkali solutions (concentration not over 10%). The outer surfaces of the porcelain bodies and pump covers a re protected f rom mechanical damage by iron a rmor . The pumps a re made up with base plates and e lec t r ica l motors . The connecting clutch is an elast ic sleeve and f inger type. To pump out liquid f rom the gland chamber and relieve the bearings f rom axial s t r e s ses , the drive wheel is made with the impeller .

Medium Speed Diesel Engine with Reduction Gear

Marine propulsion engine with reduction gear has such merits that the engine becomes smaller in size and cheaper in price by increasing engine revolution, and as for the propeller, the revolution having the highest propulsive efficiency can be easily and voluntarily obtained by selecting a certain reduction ratio.In spite of the fact that great benefits as above mentioned are given in case this engine is adopted in cargo or dredging ship, it has been rare to adopt geared diesel engine for such ship's except high speed diesel engine, for the reason that the diesel engine gives bad effects to the reduction gear by its large torque fluctuation. While, from several years on ward, our Yokohama Shipyard noticed of the utilization of the geared diesel engine having the aforesaid benefits and made the following design of it.The feature of our design is that the reduction gear is coupled with diesel engine directly with allowable large fly wheel, which is the simplest and most effective system, and there is no slip of revolution between engine and reduction gear, compared with the case of using hydraulic or electric slip coupling.One of the case is of the cargo sihp, “Matsuura Maru”, 3728 D. W. T, for the Mitsubishi Shipping Co., Ltd. The engine of this Ship is of 4 cycle single acting trunk piston with exhaust turbo charger (G 8 V 30/42, 513 rpm at 1200 PS) and is coupled with reduction gear with elastic sleeve spring “Hulsen” damper. The reduction ratio is 513/125 =4.1.Each ship is now in service in satisfactory condition.The utility of geared diesel engine was testified by its satisfactory operation and the analyzed value of measured torque fluctuation, which show the rightness and appropriateness of our design.The photograph shows the pinion gear running in good condition. As a result of this test, it was proved that the measured torque fluctuation, was only 3%.

Observations of elastic synthetic fabric sleeves as vascular prostheses.

<i>There is a best way to do everything</i>—Emerson Review of the many published reports * dealing with the investigation of plastic fabrics as vascular prostheses has led to a reappraisal of the problem in this laboratory. In those reports, although much importance has been attached to the facility with which various synthetic tubes maintain blood flow, little attention has been given to several very important aspects of the basic problem of converting commercially prepared cloth fabrics into physiologically sound and surgically acceptable substitutes for vascular segments. Great interest has been evident in comparative rates of "endothelial" regrowth, for instance, but only one observer is on record as having attached any significance to the need for some degree of elasticity in the prosthetic grafts.¹⁹Problems of wrinkling and thrombosis have been discussed, but several investigators seem prepared to accept and have, in fact, already put to clinical use, fabrics having