Abstract: A pneumatic valve drive (1) for a valve (2), in particular for a vacuum valve, which has at least one pneumatic cylinder (3) with at least one piston (4) that is movably mounted in the pneumatic cylinder (3) and at least two cylinder cavities (5, 6) arranged on opposite sides of the piston (4). Each cylinder cavity (5, 6) is connected to at least one pressure source for applying pressure to each cylinder cavity (5, 6). One of the pressure sources is a constant pressure source (7) for applying a constant pressure to the cylinder cavity (5) arranged on one of the sides of the piston, and one of the other pressure sources is a regulated pressure source (8) for applying a variably regulatable pressure to the cylinder cavity (6) arranged on the opposite side of the piston (4).

Abstract: The present invention adds gain and phase into a canonical second order system in order to mitigate the adverse effects of unwanted resonance, where the gain is added to the forward path of a control loop of the system and is a ratio of the square of the system and mechanism frequencies, and the phase lead (H-factor) is added to the feedback path of the control loop of the system and is a complex ratio of these frequencies which includes a dc-component (Hdc) and a zero- or pole-component. By adding gain and phase lead, which is contrary to current approaches to addressing resonance, the present invention achieves the desired result of resonant free application in a canonical resonant-prone system of second order, and the methodology is applicable to higher order systems.

Abstract: A self-actuated cylinder comprising a cylinder housing comprising electro-magnetic force generating means to generate electro-magnetic forces, and a piston within the cylinder housing, wherein the electro-magnetic forces act directly on the piston to displace the piston within the cylinder housing. The self-actuated cylinder can be used as an oscillation spirometer to determine air flow, an input impedance or Forced Oscillation pulmonary mechanics.

Abstract: A self-actuated cylinder comprising a cylinder housing comprising electro-magnetic force generating means to generate electro-magnetic forces, and a piston within the cylinder housing, wherein the electro-magnetic forces act directly on the piston to displace the piston within the cylinder housing. The self-actuated cylinder can be used as an oscillation spirometer to determine air flow, an input impedance or Forced Oscillation pulmonary mechanics.

Abstract: A hydraulic control device according to the invention is of load-sensing design and serves to actuate a first hydraulic load and a second hydraulic load. Also provided are a first control valve for actuating the first hydraulic load and a second control valve for actuating the second hydraulic load. A first load signal can be measured on the basis of a load pressure with which the first hydraulic load is acted on, and a second load signal can be measured on the basis of a load pressure with which the second hydraulic load is acted on. Pressure medium from a pressure medium source can be supplied in parallel to the first control valve and to the second control valve. A load signal path can, in order to actuate an adjusting element which is assigned to the pressure medium source, be acted on with a highest presently measured load signal. A limiting device allows the second load signal to be limited to a predefined signal limit value.

Abstract: The present invention relates to a brake force generator for a vehicle hydraulic brake system comprising a force input element that is connectable or connected to a brake pedal, a master cylinder, in which a primary piston is displaceably guided, wherein the primary piston with the master cylinder delimits a primary pressure chamber for generating a hydraulic brake pressure, and an actuating-force generating device for exerting an actuating force on the primary piston, wherein the actuating-force generating device comprises a control valve and a chamber arrangement, wherein the chamber arrangement is formed by a vacuum chamber and a working chamber, which is separated from the vacuum chamber by a movable wall and fluidically connectable by the control valve, and wherein the control valve comprises a control sleeve, which is displaceable relative to a valve element in accordance with a pedal actuation to achieve a pressure difference between the working chamber and the vacuum chamber that determines the actuat

Abstract: A motion converting section (31) and a translation bar (33) of a feedback mechanism (30) are provided between a lateral side of a swash plate (21) and a control sleeve (26) of a regulator (24). When the swash plate (21) is in a neutral position, the motion converting section (31) is located in an initial position (F—F) at one end of axial direction along an axis line (O—O) passing through a tilting center (C) of tilting motions, and, when the swash plate (21) is driven to tilt in a forward or reverse direction, displaced to the other end of axial direction along the axis line (O—O) to convert a tilting motion of the swash plate (21) into an axial displacement. Through the translation bar (33), the axial displacement is transmitted to the control sleeve (26) of the regulator (24) as an axial displacement.

Abstract: A hydraulic sensor and pressure transducing apparatus is disclosed which is characterized by the use of a biased piston and valve element arrangement to translate the displacement of an actuator to provide a pressure signal proportional to the displacement being sensed. The piston is mounted in a bore provided with inlet and outlet ports. A valve element is positioned in the bore in an opposing resiliently biased relationship to the piston in communication between the inlet and outlet ports. A constant selected hydraulic flow is fed into the bore inlet through the valve element and out of the bore outlet port to develop a pressure on the inlet port side which is proportionally to the displacement of the piston as reflected by the biased force exerted against the valve element. An actuator is linked to the piston by a cam surface in a manner that permits the angular position of the cam operating on the piston to be reflected as a proportional pressure on the inlet side of the valve element.

Abstract: An electrohydraulic control system for a hydraulic working cylinder, for example of a press, the piston of which has a main working surface and a smaller working surface on the rod side. A low-pressure circuit is provided for the feed or retraction movement of the piston, and a high-pressure circuit is provided for the loading movement at increased feed force and reduced speed. The connection or disconnection of these two circuits, when required, is produced with two 3/2 way valves that are coupled together. To control these control valves, there is provided an electrical reference motor that drives a cam disk which brings about the deflection of the coupled control slide valves of the control valves against a spring. A mechanical feedback is provided via the power piston, so that altogether a closed hydromechanical position control circuit is formed.

Abstract: Load actuating servomechanism apparatus includes dynamic regeneration and a mechanically damped motor-load coupling to equalize and overcome a frequency-varying load/load drive train mechanical resonance. The drive circuitry comprises a per se conventional primary motor speed controlling rate feedback loop including a cascaded rate signal command source, summing error-signal producing node, and loop frequency response shaping filter and driver amplifier for exciting a load driving motor, and a rate tachometer signal feedback element connecting a measure of the motor output speed to a subtractive input of the summing node.To broaden the response band of the primary feedback circuit and accommodate a mechanical resonance otherwise interfering therewith, a secondary, positive feedback path supplements the input rate command with a signal dependent upon motor current, and thus upon motor load.

Abstract: A fluidic driver amplifier for a servovalve has its controllably directed fluid jet differentially divided by a divider element which moves with a main valve piston in a manner to equalize the differential pressure received from the jet when the piston reaches the commanded position. In order to permit use of a small, low-leakage, fluidic driven amplifier, without the disadvantage of reduced speed of response, a derivative piston is linked to move with the main piston and displace fluid in a chamber containing a spring-centered secondary valve piston. When displaced, the secondary piston admits pressurized fluid into the main valve chamber in a positive feedback sense to aid the fluidic driver in positioning the main piston. The secondary piston is displaced only when the main piston is in motion and therefore has no effect once the main piston reaches the commanded position.

Abstract: A low friction servo valve having a housing which contains therein an input shaft, a pair of slidably mounted valve spools and an actuator. Mechanical input is received by the input shaft in order to provide rotational displacement thereof. This displacement is transferred to a flapper portion on the input shaft which operates in conjunction with a pair of jet nozzles. Movement of the flapper causes pressure buildup in one of the jet nozzles which in turn causes sequential movement of the pair of valve spools to take place. Operation of the actuator is dependent upon movement of one of the valve spools, with this valve spool also being connected to the input shaft for assisting in the rotational displacement thereof as well as being connected to a feedback spring which forces the flapper to assume its neutral position thereby reducing the pressure buildup in one of the jet nozzles.

Abstract: The dynamic performance of hydraulic apparatus including a fluid-operated actuator controlled by a servo-controller, is improved by providing phase lead compensation to the controller in response to movement of the movable element of the actuator so that the low frequency response of the apparatus is raised.

Abstract: A digitally controllable pneumatic linear actuator in which a moving piston driven by compressed air is initially decelerated by the pressure of compressed air applied to the both sides thereof in the course of its advancing movement toward a predetermined stop position and is then braked by a mechanical brake, thereby obviating failure of precise positioning of the piston due to the compressibility of air. The piston displacement is digitally detected, and the result of detection is fed back to a digital controller.