Showing papers on "Damper published in 1970"

General Motion of Impact Dampers

Abstract: The exact solution of the general steady‐state response of a sinusoidally excited primary system provided with an impact damper is derived analytically by treating the motion of the system as a piecewise linear process. The asymptotically stable regions of the resulting multivalued solutions are determined. Experimental investigations using an electronic analog computer in addition to numerical studies on a digital computer are described, and it is shown that the predictions of the theory are verified. The effects of viscous damping, frequency ratio, mass ratio, coefficient of restitution, clearance ratio, and initial conditions on the response and stability of the system are discussed, and optimum response curves over a wide frequency band are presented. The findings of this study are significantly different, both quantitatively and qualitatively from those of a recent investigation of impact dampers.

Vibration absorber for a supported member

Abstract: A series of damper dampens the vibrations in a bar extending from a quill of a bar milling machine with the damper damping each of a plurality of different natural frequencies of the extending bar depending upon the length of the extension of the bar from the quill. The damper includes a plurality of damper masses mounted on a rod with viscoelastic material between each of the adjacent damper masses and also between the supports for the rod and the adjacent damper masses. By selecting the weights of the masses and their locations on the rod, the length and diameter of the rod, and the stiffness of the viscoelastic material, the damper is designed to cover a wide frequency range, i.e., bar extension. The damper need not be tuned for each bar extension each time that the bar has a different extension since the plurality of damper masses permits the damper to dampen vibrations anywhere within the designed frequency range.

Influence of Flexible Appendages on Dual-Spin Spacecraft Dynamics and Control

Abstract: The influence of flexible antennas and solar panels on the dynamic behavior and control system response of a two-body spacecraft, one part of which may spin, is investigated. Space vehicles are modeled with a rigid platform to which are attached a rigid rotor, a damped linear oscillator (simulating a "nutation damper"), and one or more flexible appendages. Flexibility is accommodated by use of modal deformation coordinates for the appendages in combination with discrete coordinates of the platform, rotor and damper. The presence of a damper on a nonrotating platform would in the absence of flexibility and active control maintain the rotor spin axis in coincidence with the angular momentum vector. A third despin control system is designed to maintain attitude control of the platform about the bearing axis. Attitude control jets provide angular momentum control on command. Linearized equations provide the basis for digital simulation and for stability determination by eigenvalue analysis, permitting the assessment of the influence of flexible appendages on vehicle behavior.

Environmental conditioning system and method

Abstract: An environmental conditioning method removes stale air and replaces it, at least in part, with fresh air at volumetric rates that are substantially the same. The stale air from the room is delivered to a return damper with a kinetic energy level of substantially zero, and the volumetric rate of airflow from and to the room is substantially independent of the volume of air removed and replaced. A modular damper unit may be employed, which provides heat exchangers for conservation of heat energy, and the system provided is readily adapted for centralized, overall environmental conditioning by the incorporation of heating, cooling, cleaning and humidity control means therein.

Air temperature control system

Abstract: A multizone room air temperature control system comprises a thermostatically controlled louvered vent unit fitted to the mouth of the preexisting air duct register of the heating and air-conditioning system, in each room whose temperature is to be controlled. A continuously energized reversible shaded pole motor connected to the thermostat automatically opens and closes the vent louvres in response to room air temperature changes to thereby introduce or shut off the supply of either warm or cold air into the room for regulating the room air temperature independently of the other rooms.

Analysis of Unbalance Vibration of Rotating Shaft System with Many Bearings and Disks

Abstract: A method is presented for calculating the unbalance vibration of a rotating shaft system consisting of variable cross sections, disks, journal bearings and unbalances. Property of oil film bearing is assumed to be that of the springs and dampers including those which give resistance to the change of inclination angles and velocities of inclination angles. These latter springs or dampers will be called "rotational" springs or dampers. These coefficients of cylindrical journal bearings are derived from the short bearing approximation. It is concluded that the property of rotational springs and dampers of oil film in the bearing cannot be neglected, and that the calculated results obtained by means of this method agree very well with most of the experimental results for the case of rotating shaft systems with two or three cylindrical journal bearings, that of an overhung shaft system, and that of a shaft system with distortion.

Effect of Gravity on the Performance of an Impact Damper: Part 1. Steady-State Motion

Abstract: This paper, which examines the effect of gravity on the performance of an impact der, extends a previous paper (I)‡ concerned with the horizontal system. The analysis is in two parts: Part 1 which concerns itself with the calculation of all the theoretically possible steady-state motions with two impacts of the free mass, one at each end of its container, per cycle of the main mass; and Part 2§ which examines the dynamic stability and kinematic viability of the various steady-state solutions obtained in Part 1.The impact damper consists of a small mass free to move within a rigid container attached to the main vibrating system. Vibration suppression is achieved through energy dissipation during impacts and through cancellation of the effect of the external exciting force by the cyclical reaction of the free mass on the main system.The analysis shows that, in general, several different steady-state motions are theoretically possible for a given exciting frequency and that the effect of gravity on the motio...

Air damper control for refrigerators

Abstract: A refrigerator has a frozen food compartment maintained at subfreezing temperatures and a food-cooling compartment maintained at temperatures above freezing by circulation of chilled air through the compartments, the air being chilled by passing it over an evaporator operated at subfreezing temperatures in an air duct. A thermostatically actuated damper regulates the flow of chilled air into and through the foodcooling compartment according to the temperature in the cooling compartment. The damper comprises two face-to-face grilles each having a multiplicity of slots alignable with the slots of the other grille and one grille is shifted by a thermostatic element relative to the other to align more or less of the slotted areas. The thermostatic element is a vapor-filled bellows located in a housing in the chilling compartment and adjacent the air inlet. When the grilles are open air is aspirated from the compartment through the housing and in contact with the bellows and returned to the compartment with the chilled air.

Vibration damping apparatus

Abstract: A bearing and support assembly for a rotating shaft, such as a gas turbine engine rotor utilizes a damper construction employing a hydrodynamic film of oil in a relatively large clearance space, and the assembly includes means for controlling, metering and sealing the flow of oil through the damper construction and for preventing any rotation of the damper construction.

Dryer damper and control mechanism

Abstract: A dryer and damper control mechanism designed to dry articles by forced warm air including a plurality of internal baffles directing the flow of heated air through the dryer, a first set of dampers co-operating to guide the air downwardly through the articles being dried, a second pair of dampers to direct the heated air upwardly through the articles being dried and, controls to precisely regulate the temperature, humidity, and volume of the heated air through all portions of the apparatus.

Floating damper assembly

Abstract: A floating damper assembly for applying a constant damping torque to a motor shaft exhibiting substantial runout comprises a flexible cable element, which is anchored at its ends to the motor housing, and a floating damper, which is attached to the cable element substantially at the element''s center, further including an appropriately shaped bushing of frictional material and means for radially loading the bushing against the shaft. The floating damper assembly is particularly useful in an incremental stepping motor whose step profile must remain relatively constant and free of excessive ringing or overshoot.

Effect of Gravity on the Performance of an Impact Damper: Part 2. Stability of Vibrational Modes

Abstract: This paper is c oncerned with the stability of the various modes of vibration of the impact damper system described in Part 1†. Charts are presented showing the ranges of dynamically stable and kinematically viable periodic two-impact-per-cycle motion. The condition of kinematic viability ensures that the trajectory of the free mass remains within the container throughout the motion.It is shown that in general stable, viable, two-impact-per-cycle motion of the system exists under resonant conditions of the main mass and that away from resonance, where any damper is ineffective, this type of motion is generally unstable.

Self-cleaning damper assembly

Abstract: A damper assembly within a duct and a generally upright frame member having an interior damper seating surface, a shaft horizontally mounted and pivoted on the frame member with a blade member, including upper and lower body sections attached thereto. A gas jet adjacent the edge of the lower body section of the blade member affords means for removing particulate matter which tends to settle on the seating surface. A gas inlet and associated gas passageway are in flow communication with the gas jet, the gas inlet supplying a purge fluid to the gas jet. Means are also provided for rotating the blade member between first and second positions to open and close the damper.

Hydraulically damped vehicle suspension device

Abstract: A hydraulically damped vehicular suspension device comprises a self-contained damper unit which incorporates a shock absorber and which can be easily fitted into a pipe carrying a wheel-axle journal at its lower end. In order to replace the damper unit in the outer pipe it is only necessary to unscrew a lock nut and uncouple the damping cylinder of the inserted unit from the vehicle chassis. The device may also include means for cooling the damping cylinder in use.

Levelling valve assembly

Abstract: The levelling valve assembly controls the supply and discharge of air to and from a pneumatic spring by providing a valve operating lever supporting shaft separate from the drive shaft for converting the sensed variations of chassis height into a corresponding rotational movement with a damper device resiliently connected therebetween.

Combined ventilating louver and back draft damper

Abstract: A back draft air damper is incorporated within a ventilating louver with pivotally mounted damper blades movable between a closed position in which the damper blades restrict air flow in a reverse direction and an open position in which the damper blades permit a substantial flow of air in a forward direction between fixed ventilating louver blades. Each damper blade has a lower seal for engaging a next lower louver blade and surfaces along each vertical side thereof to seal against a vertical side frame member. The damper blades are hinged along their upper edges to a louver blade thereabove to provide a sealed relationship at the top of the damper blades.

Air vane and fire damper for integrated ceiling systems and the like

Abstract: An air vane is inserted in the air passage of an air diffuser and extends longitudinally above the lower portion of the outlet (the inlet if a return air unit) slot The air vane is supported at its lower surface by resting on a horizontal surface forming one side of the outlet slot of the air passage One or more pin members may be either fixedly attached to the vane itself or to a side portion of the air passage This pin member will be constructed of a suitable material, having a low melting point, so that when a fire occurs in a room area below the ceiling system utilizing the subject air vanes, the pin member will melt and vaporize thereby allowing the vane to fall downwardly and close off the outlet slot thereby providing a fire stop damper

System for the ventilation of buildings

Abstract: A system for the ventilation of buildings, comprising vertical and concentrical exhaust and injection ducts extending from a fan section located in the room to be vented to a roof hood and between said ducts a passage for recirculating part of the exhausted air to the injection duct, damper means in the form of a single unit comprising two adjustable damper members being provided in said exhaust and injection ducts and said passage for controlling the ventilation to any desired condition between full supply of fresh air and full recirculation without supply of fresh air, said damper members being constructed as double-walled elements made of a plastic material, in which a porous insulating material may be provided in the cavity between the walls. In a method for manufacturing such a damper member said member is poured from a plastic foam.

Design and application of a self-optimizing damper for increasing machine tool performance

Abstract: SUMMARY The paper proposes a new design concept for a tunable damper (damped vibration absorber). The spring rate of the device is changed by utilizing the non-linear stiffness characteristic of plastic elements. The purpose of the damper is to eliminate chatter of the machine tool by self-optimizing selection of the proper value of damper tuning. The principles for the selection of optimal values of tuning are obtained by analog computer simulation of regenerative chatter. The damper is used for increasing the dynamic stability and thus cutting performance of a vertical milling, drilling, and boring machine with a long overhung quill. Results of cutting tests are presented, illustrating the degree of chatter elimination obtained by the use of the damper.

Fire damper blade latch

Abstract: A pivotally mounted latch for a fire damper blade which is mounted to swing on a horizontal axis between an open position and a closed position. The damper is adapted to be mounted across either a horizontal or a vertical duct. The blade is normally held open by a fire responsive release and is weighted to swing by gravity to closed position across the duct when released. The latch is mounted on the outer side of the blade on a pivot axis parallel to that of the blade and extends through a slot in the blade. The latch has a plate with a generally arcuate edge which is eccentric to its pivot and which strikes a catch as the blade closes. The eccentricity of the latch plate weighs the plate to swing it into locked position behind the catch when the damper blade reaches closed position. The latch operates effectively whether the fire damper is mounted in a horizontal or a vertical position.

A Nutation Damper for a Dual-Spin Spacecraft

Abstract: This paper is concerned with a high-performance nutation damper for use in dual-spin spacecraft. The damper described here makes use of a wheel of uniform mass distribution. The wheel experiences torques which are produced by inertial forces. Damping and restoring (spring) torques are provided by means of a torsional arrangement built around the center of the wheel. The performance characteristics of the above nutation damper are evaluated by considering the small astronomy satellite (SAS-A) spacecraft parameters, and the results for an optimum design of the damper are presented. Finally, the result for the optimum performance is checked with the help of an approximate analysis.

Damper assembly for air conditioning unit

Abstract: An air ventilating arrangement for conditioning air for a served space wherein a damper assembly is provided to regulate the flow of fresh air to a served space.

Shut off damper assembly for high velocity ducted air type conditioning system

Abstract: A SHUT OFF DAMPER ASSEMBLY WHICH CAN BE INSTALLED AS A UNIT IN AN ALREADY INSTALLED SOUND ATTENUATING FLEXIBLE AIR TUBE FOR HIGH VELOCITY CONDITIONED AIR. THE AIR TUBE HAS A QUICK CONNECTOR AT ITS DOWNSTREAM END FOR CONNECTION TO AN ORIFICE DEVICE AND THE DAMPER ASSEMBLY INCLUDES A PIVOTED DAMPER TO BE INSERTED IN THE AIR TUBE TO OCCUPY A LOCATION SPACED UPSTREAM FROM THE CONNECTOR AND A CLIP MEMBER TO BE DETACHABLY MOUNTED ON THE CONNECTOR AND SUPPORT A BOWDEN CABLE SHEATH AND A SLIDE MEMBER FOR ACTUATING THE BOWDEN CABLE WIRE ATTACHED SO THE DAMPER TO CONTROL ITS ANGULAR POSITION.

Viscous torsional vibration dampers

Abstract: Viscous damping fluid is filled into a working chamber of a damper through a filling opening in the damper housing and conveyed to a reservoir through a passage in a relatively rotatable annular member mounted within the working chamber and the fluid then transferred from the reservoir to shear film spaces between working surfaces in parallel shear film spaced relation.

Torsional vibration damper having independent weights

Abstract: A torsional vibration damper comprises a hub adapted to be attached to the crankshaft of an internal combustion engine. Inner and outer weights are rotatably mounted on the hub with the inner weight being mounted within a closed annular chamber formed by the outer weight. A shear inducing disc, attached to the hub, is positioned on each side of the inner weight in the chamber. The chamber is filled with a highly viscous fluid, such as silicone, for tuning and damping purposes.

Passive eddy current nutation damper

Abstract: Nutation in a spin stabilized device is damped through the energy absorbing medium of eddy current dissipation as a permanent magnet moves with respect to a non-magnetic conductive plate. Because the nutational frequencies of the device can be determined, the damping effected by movement of the permanent magnet may be made more effective by tuning the damper to the nutational frequencies by use of a spring mechanism acting on the magnet. Nutations of the device will be damped so long as the effective damper mass of the magnet is located away from the center of gravity or center of mass of the total vehicle.

Safety mechanism for a flow conduit damper

Abstract: An additional safety mechanism of a fuse melt type applied to a damper arrangement for controlling a temperature condition of an objective circumstance such as air in a room by adjusting a flow rate of a heat medium through a conduit duct upon detection of the temperature for effecting instant intercepting of the flow path upon detection of an abnormal overheated medium''s passing in a manner independent from the flow rate controlling action.

Method and apparatus of continuous steam-atomizing fuel combustion for boiler furnace

Abstract: A METHOD AND APPARATUS FOR INITIATING COMBUSTION IN A STEAM-ATOMIZING FURNACE USING A PRESSURIZED SOURCE OF COMBUSTION AIR TO ATOMIZE THE FUEL DURING STARTUP WHEN THE STEAM PRESSURE IS INSUFFICIENT TO DO SO. A DAMPER IS PROVIDED IN THE AIR INLET TO BUILD UP THE AIR PRESSURE UPSTREAM OF THE DAMPER SO THAT THE LATTER AIR PRESSURE MAY BE DIRECTED THROUGH THE ATOMIZING NOZZLE. WHEN THE FURNACE IS UP TO TEMPERATURE AND STEAM IS GENERATED BY THE FURNACE, THE DAMPER IS OPENED TO OBTAIN EFFICIENT COMBUSTION OF THE FUEL WHICH IS THEN ATOMIZED BY THE STEAM. A SUPPLEMENTAL AIR HEATER IS PROVIDED TO ELEVATE THE TEMPERATURE OF THE PRESSURIZED AIR DURING THE STARTUP.

Periodic excitation of multiple-unit impact dampers

Abstract: The exact solution corresponding to the steady-state motion of a periodically excited primary system that is provided with a multiple-unit impact damper is derived by treating the motion of this highly nonlinear system as a piece-wise linear process. Results of the analysis are applied to the particular case of a periodically pulse excited impact damper. It is shown that such devices are efficient vibration dampers.