Showing papers on "Bearing (mechanical) published in 1972"

Knee joint prosthesis

Abstract: A prosthetic knee joint device comprises a femoral component in the form of a shell member having two condylar portions with major convex bearing surfaces areas, which portions are bridged at one end by a portion defining a trough between the convex areas. An associated tibial component has similar portions in a platform bearing member defining major concave bearing surface areas and a ridge therebetween. The convex bearing areas are longer than the concave bearing areas and generally U-shaped longitudinally to simulate the corresponding shaping in the natural joint from which the shell member can in fact be derived. The concave bearing areas however simulate the menisci of the natural joint different phases of rotation to provide an optimized congruity between the bearing surfaces during rotation of the predetermined geometry of the prosthesis as compared to the variable geometry in the natural joint.

Molded plastic bearing assembly

Abstract: A bearing assembly comprises two engaging members movable relative to one another. One of said members has a bearing surface made of metal or ceramic coated with a thin film of a parting agent, and the other bearing surface is a cured mixture of a curable acrylate composition and particulate polytetrafluoroethylene.

Limitations of the Driving Formulas for Predicting the Bearing Capacities of Piles in Sand

Abstract: It has often been shown by previous investigators that the existing pile driving formulas yield bearing capacities which usually do not stand in good correlation to the actual bearing capacities of...

A Theory of Mixed Lubrication

Abstract: The phenomena observed when a lubricated contact or bearing is operating under mixed lubrication conditions are assumed to arise from an interaction of the surface asperities or roughness as well a...

Devices including rotating members supported by magnetic bearings

Abstract: A gyroscope including a rotating member which is supported by a pair of magnetic bearings. Each bearing has two detectors for providing signals representative of the relative position of the member with respect to a common axis of the two bearings along first and second directions perpendicular to the axis and to each other. A feed-back loop controls biasing means in each bearing assembly and includes, for each direction, a summation circuit which sums the signals from the detectors corresponding to that direction in the two bearings and applies correction signals increasing with the summed signals to the biasing means corresponding to the directions in the two bearings. A subtracting circuit subtracts the signals from the detectors corresponding to the considered direction in the two bearings and applied correction signals to the biasing means, but through a polarity inverter in one of the bearings.

System for operating a prosthetic limb

Abstract: A SERVOMOTOR FOR MOVING A PROSTHETIC LIMB IS ACTUATED BY A CONTROLLER WHICH RESPONDS TO LOCAL VARIATIONS IN MUSCULAR RIGIDITY AS DETERMINED BY ONE OR MORE PRESSURE SENSORS BEARING UPON THE FLESH OF THE WEARER WITHIN AN ANNUAL FRAME CONTACTING AN AREA OF HIS BODY. THE FRAME MAY BE RESILIENTLY SUPPORTED IN A CUTOUT OF A RIGID SLEEVE BY ONE OR MORE SPRINGS URGING IT INTO CONTACT WITH AN UNDERLYING STUMP. THE CONTACTS OF THE SENSOR FORM PART OF AN ELECTROMAGNETIC VIBRATOR WHOSE OSCILLATIONS, FELT BY THE USER, ARE MODULATED BY A FEEDBACK SIGNAL CONTROLLED BY THE POSITION OR THE SPEED OF THE PROSTHETIC LIMB.

Demodulated resonance analysis system

Abstract: An apparatus for detecting defects or flaws in mechanical systems with rotating and/or reciprocating components, such as gears or bearings. The scheme utilizes a transducer, which is excited at its mounted natural frequency by the vibrations caused by the impacting of components of a device across a flaw in a bearing or the like, a filter to eliminate background noise and signals other than the natural resonant frequency of the transducer, and a demodulator which converts the resulting signal into a series of pulses in which each pulse represents an individual impact. A spectral analysis is then performed on the series of pulses to obtain the location and nature of the surface defect in the bearing or other rotating and/or reciprocating component.

Analysis of an arched outer-race ball bearing considering centrifugal forces

Abstract: A Newton-Raphson method of iteration was used in evaluating the radial and axial projection of the distance between the ball center and the outer raceway groove curvature center (V and W). Fatigue life evaluations were made. The similar analysis of a conventional bearing can be directly obtained from the arched bearing analysis by simply letting the amount of arching be zero (g = 0) and not considering equations related to the unloaded half of the outer race. The analysis was applied to a 150-mm angular contact ball bearing. Results for life, contact loads, and angles are shown for a conventional bearing (g = 0) and two arched bearings (g = 0.127 mm (0.005 in.), and 0.254 mm (0.010 in.)). The results indicate that an arched bearing is highly desirable for high speed applications. In particular, for a DN value of 3 million (20,000 rpm) and an applied axial load of 4448 N (1000 lb), an arched bearing shows an improvement in life of 306 percent over that of a conventional bearing. At 4.2 million DN (28,000 rpm), the corresponding improvement is 340 percent. It was also found for low speeds, the arched bearing does not offer the advantages that it does for high speed applications.

Foil bearing arrangements

Abstract: A self-pressurizing hydrodynamic foil bearing having resilient foils providing support between a movable and stationary bearing member and further having resilient foil supports for supporting and stiffening the foils. The foil supports additionally generate Coulomb friction with another bearing member for enhancing the damping characteristics of the bearing.

Gas filled vertical dynamoelectric machine

Abstract: A totally enclosed, inert gas filled vertical dynamoelectric machine is described wherein liquid lubricant in the lower bearing housing is employed to seal the machine output shaft against the loss of inert gas. To inhibit loss of lubricant from the seal, a stationary oil sleeve concentrically disposed within a zone between the rotor shaft and shaft sleeve protrudes to a height in excess of the oil level within the housing by an amount at least equal to the change in level produced by the pressure of the inert gas within the machine. The lower bearing preferably is enclosed by a selectively notched bearing cover which serves in conjunction with annular grooves upon the shaft sleeve to prevent oil creepage along the exterior of the shaft while blow-out of oil from the seal by excessive gas pressure within the machine is inhibited by a liquid filled, generally U-shaped tube communicating the motor interior with the ambient. To prevent turbulence produced by rotation of the rotor from breaking the seal, the lubricant should extend to a level above the bearing or a selectively apertured partition could be inserted between the lower end of the shaft sleeve and the bearing.

Angle type feedthrough cable clamp

Abstract: A cable clamp adapted to be made of one piece of synthetic material has a base bearing a feedthrough hole for placing in registry with a knock-out hole in an appliance housing and has a clamp seat onto which the cable issuing out of the hole is bent. A cover connected to the base with a live hinge bears the upper jaw of the clamp and is adapted to be fastened onto the clamp seat and base by screws. The feedthrough opening in the base has a semi-circular flange protruding through the corresponding opening in the appliance housing. The flange has a lip for engaging the rear surface of the housing.

Swing bearing with bolt-on segmented gear

Abstract: There is disclosed a swing bearing in combination with a swing gear for the slewing platform of hydraulic excavators and the like. The swing gear comprises a plurality of gear segments detachably secured to one race member of the bearing assembly in a manner to form a continuous annular gear element or member. The combination is constructed so that individual segments of the gearing can be removed and replaced without removing the slewing platform.

Air cooling of turbine blades

Abstract: A gas turbine engine is described, particularly the turbine rotor portion thereof and the bearing for journaling this rotor. Cooling air is directed along passageways extending through the bearing mounting and discharged into an entry chamber at the inner portion of the rotor. The rotor includes an annular plate spaced from a disc on which the rotor blades are mounted. The inner periphery of the plate defines the entrance of a passageway means for the flow of cooling air from the entry chamber to and through the blades to cool them. Cooling air as it is directed into the entry chamber at an angle such that its tangential vector approximates the peripheral speed of the cooling air passageway entrances. Further, vanes are provided on the blades to facilitate flow of cooling air through the rotor passageway means.

Laminated composite article with improved bearing portion

Abstract: A composite article having a body of at least one layer of glass fibers includes a pair of opposed outer bearing portions connected with the body, at least one outer bearing portion including ingredients of graphite, carbon or their mixtures, such as in fiber form, to provide improved bearing characteristics. The article is bonded together through a polymer resin. In one form, the article includes a low coefficient of friction material at least as a coating on the bearing portion, especially for very thin, lightweight bearing designs.

Lubricating system for vertical machine elements

Abstract: Means for lubricating a bearing in a mechanism which is operated intermittently, the illustrated example of which is the main drive bearing of a refrigerant compressor of the type having a casing wherein lubricant normally stands at a level and wherein the refrigerant compressing mechanism and a motor for driving it are mounted in the casing above that level, the means comprising a generally vertically disposed drive shaft having a portion journaled in the bearing, means supporting the drive shaft with the drive shaft portion journaled in the bearing disposed above said level, means for rotating the drive shaft, means defining a recess within the drive shaft adjacent the bearing and defining a passage through which lubricant may flow from the recess to the bearing, lubricant pump means extending into the lubricant reservoir below said level and extending into the recess and effective to pump lubricant from the reservoir into the recess, the means defining the recess including means retaining lubricant in the recess when rotation of the pump stops and the lubricant pump means stops so that such retained lubricant may flow from the recess through the passage to lubricate the bearing when rotation of the drive shaft resumes.

Stability and transient motion of a vertical three-lobe bearing system

Abstract: Stability characteristics and general transient motion of vertical finite width three lobe journal bearing, assuming incompressible fluid with cavitation

Nonuniform Magnetic Field Effects in MHD Slider Bearing

Abstract: A theoretical analysis is made of a slider bearing using an electrically conducting lubricant in the presence of a nonuniform magnetic field applied perpendicularly to the bearing surfaces. In the differential equations inertia terms are retained and the solution is obtained numerically for low Hartmann numbers. The results indicate that the contribution of inertia terms decreases with the increase of Hartmann number and that the nonuniform magnetic field gives higher load capacity than the comparable uniform magnetic field.

Low friction fabric-lined bearings and improved fabric therefor

Abstract: Unblended yarns are constructed and woven with other yarns to form a mixed fabric which is particularly suitable for use as the liner for resin bodied annular bearings which are subject to reversing loads, that is where one bearing element oscillates relative to the other or relative rotation or movement of the bearing elements regularly reverses in direction. More particularly, yarn of Teflon filaments and yarn of bondable filaments are woven in a 1 x 1 plain weave so that the filaments are just sufficiently loose to allow the capillary action of the liquid resin to thoroughly impregnate the fabric in the manufacture of the bearing and anchor the Teflon filaments to prevent their being worked loose from the resin by the reversing loads.

Shaft damping arrangement

Abstract: Imbalance vibration of each of two concentric rotating shafts is damped simultaneously by a single damped bearing. By supporting one of the shafts on a damped bearing which is fixed to ground, and by transmitting imbalance vibration from the other shaft into the first shaft by means of a nondamped intershaft bearing, the imbalance vibration of both shafts is damped by the single damped bearing.

Criteria for self loosening of fasteners under vibration

Abstract: A UNIQUE TEST method and apparatus now make it possible to reproduce conditions of vibration that are not only certain to loosen bolted joints but which also closely simulate actual conditions. It can be shown that properly preloaded fasteners loosen as a result of rotation as soon as relative motion occurs between the mating threads and between the bearing surfaces of the fastener and the clamped material.

Sequential control circuit for a remote-controlled vehicle

Abstract: A remote-controlled motor-driven vehicle responsive to a control signal transmitted by a portable transmitter carried by a moving individual for transporting a load at a predetermined distance behind the individual has an improved control system which includes a receiver for detecting the transmitted signal and developing therefrom a range signal representative of the distance between the individual and the vehicle and bearing signal representative of the heading of the vehicle relative to the individual. A motor control circuit is responsive to the application of the range and bearing signals for controlling the speed and direction of said vehicle. A detector is coupled to the receiver and is responsive to the reception of the control signal for developing an actuating signal. A switching circuit is coupled between the receiver and the motor control circuit and is responsive to the actuating signal for causing the motor control circuit to first respond to the bearing signal and then respond to the range signal to thus sequentially steer the vehicle in the proper direction and then move the vehicle to the desired distance behind the individual.

Self-aligning bearing assembly

Abstract: A self-aligning bearing assembly having a single piece, stamped housing of general cup-shaped configuration, an opening in the bottom of the housing for seating a spherical bearing ball and spring fingers extending from the bottom of the housing for engaging the diametrically opposite side of the ball and retaining it in the housing.

A Demonstrably Optimum One Dimensional Journal Bearing

Abstract: By the use of a new variational technique, the bearing profile which maximizes the load carrying capacity of an infinite length journal bearing is obtained. The lubricant is assumed to be incompressible and of constant viscosity. The flow is assumed to be laminar and the optimization is based upon a minimum film thickness. The solution obtained is a concentric step bearing with a film thickness ratio of 1.812 and a ridge to pad ratio of 0.328. It is mathematically shown by the use of the “nonlocal” formulation that this step profile does yield a maximum among all profiles sufficiently “close.”

Arrangement for mounting bearings

Abstract: An arrangement for mounting a bearing to the surface of a machine part in which the bearing has an inner and an outer race ring. The race ring opposed to the machine part is formed with a conically tapered surface forming a corresponding space therebetween. A radially extending annular flange is provided along the edge of the conically formed ring and a wedge block is located within the space. The arrangement is provided with screw means by which the block is securely pressed and forced into engagement with both the conical surface and the surface of the machine part.

Ear muff assembly

Abstract: An ear muff assembly for use with a headband including an ear cup, a circumferentially extending first bearing, the ear cup being mounted in the first bearing for rotation about a first axis, a yoke, the circumferentially extending bearing being mounted in the yoke for rotation about a second axis which extends laterally of the first axis, the yoke being mountable on the headband.

Concentric tube spring rotor mount

Abstract: The helicopter main rotor is mounted on a rotating support mast by feathering bearings and flapping bearings to provide pitch change control and to tilt the rotation plane of the rotor Rotor tilting is provided by the flapping bearings coupling a blade yoke to the mast The flapping bearings are elastomeric elements fitted onto pivot shafts on a trunnion mounted on the mast These elastomeric elements also mount in bearing blocks bolted to the rotor yoke To increase the control power about the pitch and roll axis of the aircraft, particularly at rotor loadings of less than one ''''G,'''' a concentric tube torsion spring interconnects pivot shafts of the trunnion to respective bearing blocks Each of the concentric tube torsion springs includes an inner tube mounted within an outer tube and joined together at the outboard ends The inboard end of the inner tube connects to the pivot shaft and the inboard end of the outer tube connects to the bearing block

Ferrohydrodynamic low-friction bearing with improved volume compensation and fluid seal

Abstract: A self-contained, full film hydrodynamic bearing is provided having a ferrofluid (colloidal suspension of magnetic particles) with magnetic properties which facilitates retention of the fluid within the bearing where the bearing retains the ferrofluid over a wide temperature range and concomitantly compensates for ferrofluid expansion and contraction.

Reevaluation of the stress-life relation in rolling-element bearings

Abstract: Four groups of 12.7 millimeter diameter vacuum-degassed AISI 52100 balls were tested, each at a maximum Hertz stress in the range of 4.5 times 10 to 9th power to 6.0 times 10 to 9th power N/m2. Tests were run in the five-ball fatigue tester at a contact angle of 30 deg and a shaft speed of 10,000 rpm. The 10 percent fatigue lives at the four stress levels indicated that fatigue life is inversely proportional to maximum Hertz stress raised to the power of 12. This result agrees with a survey of the literature which suggests that a stress-life exponent of approximately 12 is typical of vacuum-processed bearing steels rather than the exponent of 9 which has been generally accepted by the bearing industry.