Showing papers on "Actuator published in 1977"

An Electrohydraulic Knee-Torque Controller for a Prosthesis Simulator

Abstract: A new approach for evaluating advanced concepts for knee-joint control in above-knee prostheses involves the use of a simulator prosthesis which can be worn by an amputee and controlled electronically to emulate proposed future prostheses. A critical element in this system is the knee-torque controller. Realization of a powerful, lightweight, easily controlled transducer was essential to the successful development of the simulator system. This paper presents the design of such a controller and evaluates its performance. Brief examples of studies in which the new system has been applied are given. The proven viability of the device suggests that similar actuators might aid other prosthesis/orthesis studies.

Two axes controller

Abstract: A two axis controller for controlling a tanker aircraft in-flight refueling boom while maneuvering prior to engagement with the receiver aircraft and including a boom load alleviation system after engagement Movement of the control stick is transmitted mechanically to a position transducer The transducer provides a signal to an actuator to effect boom control The transducer output is also transmitted to a servo motor which is mechanically connected to the control stick During the free flight mode, when the operator is manually controlling the boom, the servo motor provides a resisting force to stick movement that varies as a function of the transducer signal Following coupling of the two airplanes, which initiates the automatic load alleviation system, the same servo motor back drives the control stick in response to boom force and position signals to alleviate boom forces Manual override of the automatic system is possible at any time

Pneumatic-hydraulic actuator system

Abstract: An actuator system is disclosed which modulates a linear output shaft associated with a working control valve or the like in response to a control signal input The system includes a feedback control link, a pneumatic positioner, a pneumatically controlled hydraulic valving system and a hydraulic cylinder and piston assembly controlled by the hydraulic valving system The hydraulic valving system includes a three-position, four-way valve actuated by pneumatic binary output signals from a signal conditioner which is in turn controlled by the positioner Hydraulic flow to the three-position, four-way valve may also be controlled from the signal conditioner in response to positioner output for most effective actuation of the hydraulic cylinder and piston assembly Failure modes are also disclosed with the present system The resulting system exhibits extremely rapid response times and high accuracy with dynamic stability

Fail safe redundant actuator

Abstract: An electromechanical actuator is provided which is capable of disconnecting the output shaft and the drive mechanisms in such a way that, in the event of either a rotational or translational failure during operation, the output shaft can be effectively freed in such a manner that it will not resist the motion produced by other actuators which have not failed.

Quick disconnect coupling

Abstract: A quick disconnect coupling for coaction with a checkvalve equipped male coupling is provided with a lockable spool and a lockable valve actuator. A first locking pin on the spool locks the spool when the male coupling is not coupled with the female coupling and is engageable with the male coupling for unlocking the spool when the male coupling is inserted into the female coupling. The locking mechanism for the actuator permits the actuator to move when a pressurized male coupling is inserted and locks the actuator when the actuator opens the check valve.

Electrically controlled door lock

Abstract: A door lock for use on a door panel has bores containing a lock mechanism including a chassis on which spindles are mounted for rotation about two parallel axes. Door handles or other lock operators are disposed on opposite ends of both spindles and are interconnected variously to operate a lock bolt and a latch bolt. The lock and latch bolts are also disposed in the bores and are joined to the chassis. One of the handles is joined to one of the spindles by a clutch including an axially movable member operated by an electromagnet within the bores, the electromagnet being connected to the clutch member by an actuator movable in a path having an axial component.

Motion control system

Abstract: Positioning and motion control of two objects, for example, of a transducer and a disk record medium having tracks including pre-recorded servo information, is achieved in two modes of operation in the following manner: During a track following mode the transducer is connected in a closed servo loop and position error signals derived by the transducer are used to energize an actuator mechanism coupled to the transducer so as to maintain the transducer in the on-track position. During a track seek mode, the actuator is energized to cause the transducer to follow a desired velocity profile, at least a part of which is achieved with the transducer connected in a closed servo loop. The loop is fed with position error signals derived by the transducer sampled at times calculated to coincide with the on-track positions of a transducer following the desired velocity profile. The servo system responds as in track following mode to energize the actuator mechanism so as to reduce the instantaneous transducer position error from the true on-track positions during this part of the access operation with the overall effect of causing the transducer to follow the desired velocity profile more closely.

Transducer lifting means employing plural flexures

Abstract: A flexure supported actuator arm carries a plurality of transducer means, each connected to the actuator arm by one flexure; all transducer means are loaded or unloaded by a common lifting mechanism.

Motor driven lock actuator

Abstract: A self-contained electric power driven bolt actuator unit for installation with a high security door locking mechanism comprising a housing adapted to be mounted on the door in operative association with the lock mechanism, a rotatable actuator shaft being mounted in the housing and connected at one end with a bolt actuating cam, an electric motor connected to drive the actuator shaft through a friction driving connection, a manually operable knob for overriding the actuation of the bolt by the cam independently of the motor, and switching means operable upon predetermined rotation of the actuator shaft in each direction of its rotation to reverse the driving direction of said electric motor and for indicating the operative position of the bolt of the locking mechanism.

Device for crimping tubular elements

Abstract: There is disclosed a device for crimping couplings to the ends of hydraulic hoses in which a plurality of die means are located around an axis, camming means is provided and is arranged to cause the die means to move radially inwardly towards the axis when the die means and camming means are moved axially relative to each other, and a hydraulic actuator is provided for causing that relative axial movement. When a coupling is inserted between the die means, operation of the hydraulic actuator causes the die means to move inwardly and thereby compress or crimp the coupling. The hydraulic actuator has an annular hydraulic fluid chamber to which pressure is applied to operate the actuator. Further features are that adjusting means is provided, for pre-setting the outside diameter to which the device will crimp a coupling, the adjusting means being co-axial with the device for increased accuracy, and having a construction which involves no projecting parts, so as to avoid damage. Means is also provided which prevents the device being operated further than a pre-set crimped diameter, so as to prevent an operator from overcrimping a coupling once the device has been properly pre-set.

Roll lifting apparatus

Abstract: The disclosure is directed to apparatus adapted for attachment to an overhead crane which lifts and maneuvers material wound on rolls, coils, reels and spools. The apparatus comprises an elongated housing which is suspended in a generally vertical position at its upper end from the overhead crane. An elongated probe assembly constructed for insertion into one end of the roll core is pivotally mounted intermediate its ends to the lower end of the housing so that it is capable of swinging between vertical and horizontal positions. The probe itself includes means for expanding its effective diameter upon entry into the core, thus permitting it to be securely retained within the core and to lift the core from this single internal region of contact. The opposite end of the probe assembly is pivotally connected to the rod end of an hydraulic actuator which is pivotally mounted to the elongated housing. As connected, extension of the actuator rod swings the probe from the vertical to a horizontal position, and retraction of the rod returns the probe to the vertical position.

Apparatus for automatically turning pages

Abstract: Apparatus for sequentially turning stacked pages includes several actuator driven elements. These include a pusher to frictionally push an exposed page in a turn direction and resulting in upward bulging of the page; a foot to clamp a page to be turned to facilitate development of the bulge; at least one flipper arm to swing under the bulge and flip the page over; and a turned page holder that temporarily lifts to allow a turning page to be received on a stack of turned pages, for subsequent clamping by the holder. The actuator includes a linearly moveable member that is motor driven and that actuates the elements. Also provided are a holder for pages to be turned; a string to hold down groups of turned pages, and a receptacle for a book (as for example a paper back book), the receptacle being capable of inversion to allow a bed-ridden reader to use the apparatus with no effort spent in turning pages.

Buckling spring torsional snap actuator

Abstract: A torsional or rocker switch actuator is described that uses the torsional moment of a buckling compression spring column to rock the actuator member on a pivot. A catastrophically buckling compression column spring is used and the reaction moment which occurs as the spring buckles is applied to rock an actuator back and forth between open and closed positions with cooperating contacts beneath the actuator. A non-teasible, snap action, tactile feedback, key mechanism of extreme mechanical simplicity and high reliability is achieved.

Hydraulic control system for press brakes and the like

Abstract: A control and actuator system for a press brake having a frame, a bed, a ram, and a pair of hydraulic cylinders for reciprocating the ram, utilizes a jackscrew arrangement in conjunction with positive mechanical stops on the ram pistons to support the ram beneath the cylinders to enable the bottom travel limit of the ram to be preset. The top travel limit of the ram is preset by means of vertically adjustable actuator rods on the ram, which engage actuator stems on valves associated with each cylinder to stop upward travel and hold the ram in position. Tilt compensation is provided at the top and bottom ram limits by independent adjustment of the jackscrews and actuator rods, obviating the need for a complex tape and pulley driven differential valve arrangement. The novel hydraulic circuit provided for powering the cylinders utilizes pilot-driven control valves, and provides for direct venting of the system high-volume hydraulic pump when not in use to maximize system efficiency.

Crash stop for disc drive actuator

Abstract: A crash stop for use in a rotary disc file storage system, particularly for use with a rotary-type electromechanical actuator, the crash stop comprising a dual stop mechanism for delimiting the travel of an actuator arm in either of two reciprocal directions, the stop having two symetrically oriented plain levers having separate spaced pivots, the levers each having first segments projecting from the pivot and adjustably spaced on either side of a stop pin fixed on the actuator arm and second segments oppositely projecting from the pivot and interconnected by a spring loaded, adjustment mechanism, whereby movement of the actuator arm is restricted by contact of the stop pin with one of the first lever segments and limited compression of a spring in the adjustment mechanism.

Portable track lighting

Abstract: A lamp and support housing are adapted for movement along the length of a power supply track. The track is portable since it is removably connected to wall brackets. The housing supports movable contacts each adapted to be electrically coupled to a discrete conductor bus in the track. Access to the conductor buses is attained by way of slots on opposite faces of the track. A discrete actuator on the housing moves each contact between an inoperative retracted position and an operative extended position.

Theory of multidither adaptive optical systems operating with zonal control of deformable mirrors

Abstract: A theory is developed for multidither adaptive optical systems that employ N discrete actuators driving a deformable control and dither mirror with the same shape of influence function. The major emphasis is on mirrors with a Gaussian influence function. It is shown, as a special case, that single-actuator displacements or errors of such systems yield error signals that can be described in closed form, via sine integral functions of the actuator displacement. Closed-form expressions for both the first- and second-harmonic content in the dither signal outputs are developed. Expressions for servo cross coupling (from adjacent actuator deformations) are developed and it is shown how the coupling is typically larger than the mechanical (actuator center) coupling. Effective modulation index comparisons are established between Gaussian and piston mirrors, for piston and Gaussian phasing error components. It is shown how a potential secondary maxima lock-up condition (the 2nπ problem) can occur when operating hill-climbing adaptive optical systems with deformable mirrors. In some cases a major loss in system Strehl ratio may result.

Intravenous alarm system

Abstract: A monitoring device which monitors the extent of infusion of intravenous solutions and provides an alarm signal when such infusion has progressed to a predetermined degree. The device comprises a cylindrical container to which is coupled, at its upper end, an attaching member for suspending the device from an intravenous solution supporting stand. Peripherally disposed about the cylindrical container are electrical sockets adapted such that each socket may accept an associated electrical plug. Extending through and below the lower end of the cylindrical container is a suspension member having a hook section for suspending an intravenous solution container. A helical spring is disposed within the cylindrical container, coaxially surrounding that portion of the suspension member which extends into the cylindrical container. The vertical position of the spring is defined by the lower internal end of the cylindrical container and by the upper extremity of the suspension member disposed within the container. At the juncture of the upper extremity of both the suspension member and helical spring is an actuator adapted such that electrical contact may be selectively made between the actuator and the electrical plug. The helical spring, suspension member, electrical plug, and actuator are disposed within the container such that as the quantity of intravenous solution diminishes, the actuator moves vertically upward toward the plug, ultimately making electrical contact and thereby actuating an alarm.

Method of and arrangement for controlling manipulators and industrial robots

Abstract: This disclosure is drawn to a method of and an arrangement for controllinghe rotational and translatory motions of a manipulator or industrial robot, which automatically for the entire motion and speed range, even when there is simultaneous movement of a plurality of motion actuators, permit uniform, selectible and disturbance-independent dynamic control properties for individual or all motion parameters. The invention is characterized in that for each rotational or translational motion parameter of the manipulator or industrial robot to be controlled the positioning signal of the associated motion actuator is in part generated by a control means with selectible dynamics. This controller output signal is amplified multiplicatively by the output signal of an arrangement which for a rotational motion reproduces the associated variable moment of inertia and for a translatory motion the associated mass, respectively, inclusive of the variable load mass. The controller output signal is amplified to such an extent that thereby the effect of the variable moment of inertia or of the variable mass is compensated. The other part of the positioning signal of the associated motion actuator is supplied additively by the output of a further compensation arrangement which reproduces the dynamic intercouplings with the other motion variables so that the interference effect upon simultaneously varying a plurality of motion variables is eliminated.

DC Servomotors-Modeling and Parameter Determination

Abstract: Present methods of defining and measuring the parameters of separately excited dc servomotors are inadequate. Eight practical servomotor models are identified, and the parameters of each model are clearly defined. Testing procedures are given for determining a servomotor's model type and all the model parameters based only on the current response of the machine to a step input of armature voltage. Excellent agreement is obtained between the actual current responses of several servomotors and their predicted responses obtained from the corresponding mathematical models, indicating the efficacy of the technique.

Apparatus for selective electroplating of workpieces

Abstract: The apparatus comprises a plating unit, the cavity of which communicates with a plating solution feed system, and pressing means mounted above the plating unit. The pressing means according to the invention is made in the form of a magazine with two or more pressure surfaces whereon sealing members, workpiece orientation members and workpiece retaining members are mounted. The magazine is operatively connected to a vertical movement actuator in a manner which provides for rotation of the magazine about its horizontal axis. A masking member is mounted on the surface of the plating unit to mask the workpiece surface areas not to be plated. The apparatus comprises an anode which is mounted in the internal space or cavity of the plating unit in the path of the plating solution flowing towards the workpiece, and a cathode connected to the workpiece. The apparatus ensures a higher efficiency of the plating process, due to the fact that simultaneously with the plating of workpieces pressed between the plating unit surface and one of the pressure surfaces of the magazine it is possible to remove plated workpieces from and place the next lot of workpieces to be plated onto the other pressure surface.

Turbocharger control actuator

Abstract: A control actuator for a turbocharger comprises a diaphragm-displaced actuator rod projecting outwardly from an actuator housing through a seal permitting axial and angular rod movement for variably positioning a turbocharger wastegate valve.

On the edge singularity of an actuator disk with large constant normal load

Abstract: In this paper some aspects of the nonlinear potential theory of actuator disks are considered. A rather general formulation of the problem for a prescribed load on a curved surface is given. For the special case of constant normal load and no incoming velocity the singular behavior of the flow at the edge of the disk is discussed.

Apparatus for equalizing pressure and absorbing shock in a pneumatic braking system

Abstract: Apparatus for equalizing pressure and absorbing shock to prevent single wheel lock-up in a pneumatic braking system including a pneumatic source coupled by air lines to two brake actuators and being subject to the presence of contaminants of the water droplet and particulate type, the apparatus comprising a walled housing including an inner surface forming an elongated cavity having a first port for connection to the pneumatic source and a second port for connection to one of the actuators, the cavity being configured to form a first chamber that communicates with the first and the second port and to form a second chamber, a rigid piston having a first end and an opposed second end, an elongated resiliently yieldable, shock absorbing member disposed within the cavity between the second end and an opposite wall of the cavity, the member having an outer surface and a transverse cross-sectional dimension less than the corresponding transverse cross-sectional dimension of the cavity such that the separated outer surface of the member and the inner surface of the housing form the second chamber, and a resilient covering extending from the periphery of the inner surface over the first end, the covering serving to seal the piston, member and second chamber from the contaminants, whereby an increase in pneumatic pressure in the first chamber is transmitted through the covering to the piston, causing the piston to deform the member into the second chamber

Redundant EHV fault detector

Abstract: Plural servo actuators are coupled to provide a redundant system for operating a common output device. Each servo actuator has plural servo valves each having one active output that causes controlled opposite operation of the output device and one passive output. A fault detector coupled to each servo actuator compares the sum of the passive output pressures with the pressures of two other fluid signals, in one case the supply and return fluid signals and in another case the two active output signals of the servo valves, to detect the condition thereof. A convenient checkout system and a fluid by-pass mechanism also are provided in the fault detector.

Actuator for pushbutton switch

Abstract: An actuator for pushbutton type switches comprising a single molded plastic unitary structure. The actuator provides for operation of both locking and nonlocking switches and for actuation of switches mounted both parallel to and perpendicular to the plane of operation of the actuator.

Cruise control device for vehicles

Abstract: A speed control device for a vehicle driven by an internal combustion engine comprises a longitudinally movable actuator member connected to the accelerator control linkage of the engine, a longitudinally movable abutment member, a device for optionally locking the abutment member against longitudinal movement, a spring and a flexible diaphragm connecting the actuator and abutment members, and means for applying manifold vacuum from the internal combustion engine to the diaphragm whereby to vary the relative positions of the actuator and abutment members. Preferably the device locking the abutment member is controlled by an acceleration responsive device so as to unlock the abutment whenever the vehicle is subjected to more than a predetermined degree of deceleration.

Magnetic bearing momentum wheels with magnetic gimballing capability for 3-axis active attitude control and energy storage

Abstract: Magnetic bearings used for the suspension of momentum wheels provide conclusive advantages: the low friction torques and the absence of abrasion allow the realization of lightweight high speed wheels with high angular momentum and energy storage capacity and virtually unlimited lifetime The use of actively controlled bearings provides a magnetic gimballing capability by applying the external signals to the two servo loops controlling the rotational degrees of freedom Thus, an attitude control system can be realized by using only one rotating mass for 3-axis active satellite stabilization

Speed-variable limits in fail-safe actuators

Abstract: A positioning device for a critical aircraft surface, such as a stabilizing elevator in a helicopter, includes a pair of reversible electric jack-screw type actuators acting in series, each being controlled in a closed-loop fashion by separate electronic hardware, the position of each as well as the rate of change thereof being compared with the other, against limits which, according to the invention, are relatively broader at low speeds and are tightened at higher speeds. If either of the positions or the rate of change of positions of the two actuators fail to track within the variable threshold disparity, an alarm condition is manifested and the actuators are disconnected from automatic control and rendered operable by manual control.