Abstract: A temporary joint that includes a first discrete member having a first edge and a first movable coupling means; and a second discrete member having a second edge and a second movable coupling means. When it is necessary to form a joint between the first and second discrete members, the first and second edges are moved into abutment to define a binding edge. Then, the first and second movable coupling means are moved toward the binding edge; and the temporary joint is formed when the first and second movable coupling means are proximate the binding edge. The joint is broken by moving the first and second coupling means away from the binding edge. The first coupling means is comprised of a volume of a field responsive material and the second coupling means is a field producing means such as a magnet. A rigid joint is produced when the field producing supplies a field across the field responsive material.

Abstract: A seismic MR damper for providing controllable damping forces between a first structural member and a second structural member within large structures, such as buildings, bridges, etc.

Abstract: According to the present invention, a haptic interface system, also known as a force feedback system, comprises a motor for supplying actuating energy and a magnetically-controllable device that transfers the actuating energy into force feedback sensations. The magnetically-controllable device contains a magnetically-controllable medium beneficially providing variable resistance forces in proportion to the strength of an applied magnetic field. The system further comprises a computer system having a processor that runs an interactive program or event, a video display for displaying the interactive program or event, and a haptic interface device in operable contact with an operator for controlling inputs to the interactive program.

Abstract: A controllable damper for resisting movement between two relatively moveable members includes a first member and a second member coupled for relative movement having a working space between them, and a controllable medium retaining structure, for example, an absorbent matrix, to hold a controllable medium only in the working space. A cage preferably supports the matrix. A field generating coil is mounted to one of the first and second members to generate a field acting on the first and second members and the controllable medium in the working space. The rheology change in the medium produced by the field results in resistance to relative movement of the first and second members. A device according to the invention may be used in apparatus, such as washing machines, exercise equipment, air supported tables, and a range of other apparatuses that would benefit from controlled damping or braking. Devices including a two-piece outer housing are described.

Abstract: A magnetorheological brake includes an outer, rotating flywheel member having a hollow interior space, and an inner fixed member disposed in the hollow interior space. The inner fixed member is sized so that a working space is provide between the surfaces of the fixed member and the inner wall of the rotating member. A controllable medium of magnetically permeable metal particles is disposed in the working space. A field generator is mounted in the interior space to the fixed member to selectably generate a field acting on the outer and inner members and the controllable medium in the working space. The rheology change in the medium produced by the field generates resistance to rotation of the outer member about the inner member. A device according to the invention may be used as a flywheel/brake or resistance-generating device in exercise equipment, rotating equipment, such as conveyors, and vehicles.

Abstract: A controllable valve assembly (18) applicable in Magnetorheological (MR) fluid devices (20), such as MR mounts and MR dampers. The valve assembly (18) includes a valve body (32) having a magnetic circuit (40) contained therein which carries magnetic flux .phi., a controllable passageway (42) within the magnetic circuit (40), a MR (magnetically controlled) fluid (44) including soft-magnetic particles in a liquid carrier contained in the controllable passageway (42), a magnetic flux generator, such as a wound wire coil (46), generating magnetic flux .phi. which is directed through the MR fluid (44) in the controllable passageway (42) thereby generating "rheology" changes causing restriction in flow of MR fluid (44) therethrough.

Abstract: A controllable medium device for resisting movement (rotary, linear, or sliding) between two relatively moveable members includes a first member and a second member coupled for relative movement having a working space between them, and a controllable medium retaining structure, for example, an absorbent matrix, to hold a controllable medium only in the working space. A field generating coil is mounted to one of the first and second members to generate a field acting on the first and second members and the controllable medium in the working space. The rheology change in the medium produced by the field results in resistance to relative movement of the first and second members. A device according to the invention may be used in apparatus, such as washing machines, exercise equipment, air supported tables, and a range of other apparatuses that would benefit from controlled damping or braking.

Abstract: An adjustable valve including a passageway, a field responsive fluid within the passageway, and flow adjustment of the fluid through the passageway. In another aspect, the valve is in a vibration damper. In yet another aspect, the damper includes a body, a piston, first and second chambers, a damping valve, a piston rod, an auxiliary chamber, a passageway interconnecting to the auxiliary chamber, a field responsive fluid, a field responsive fluid valve for controlling flow to the auxiliary chamber, and pressurization means. Preferably included is a cavity partition having field responsive fluid disposed on one side and non-field responsive fluid disposed on the other. This allows a reduction of MR fluid allowing use of lighter-weight, less-expensive, hydraulic fluids for flow through the piston's damping valve. In another aspect, the damper includes mechanical adjustment device for manually adjusting a damping level.

Abstract: Magnetorheological fluid compositions that include an aqueous carrier fluid, magnetic-responsive particles and an additive selected from bentonite or hectorite. This fluid exhibits excellent stability and is easy to re-disperse. Preferably, all the ingredients are inorganic.

Abstract: A device for hand and wrist rehabilitation includes a small, hand-held housing for a magnetic fluid controllable resistance brake. Tool elements that provide a grip for a patient releasably snap onto to a shaft of the brake, and allow the patient to exercise the wrist or hand in a variety of positions. The controllable brake provides fine control of the resistance, which is selected by the user with a knob.

Abstract: A controllable valve assembly (18) applicable in Magnetorheological (MR) fluid devices (20), such as MR mounts and MR dampers. The valve assembly (18) includes a valve body (32) having a magnetic circuit (40) contained therein which carries magnetic flux .PHI., a controllable passageway (42) within the magnetic circuit (40), a MR (magnetically controlled) fluid (44) including soft-magnetic particles in a liquid carrier contained in the controllable passageway (42), a magnetic flux generator, such as a wound wire coil (46), generating magnetic flux .PHI. which is directed through the MR fluid (44) in the controllable passageway (42) thereby generating "rheology" changes causing restriction in flow of MR fluid (44) therethrough.

Abstract: A magnetorheological fluid that includes a carrier component and a magnetizable particle component wherein the magnetizable particle component is a mixture of at least a first particle group having an average particle diameter and a second particle group having an average particle diameter wherein the average particle diameter of said first particle group is 3 to 15 times larger than the average particle diameter of said second particle group.

Abstract: A controllable platform suspension system (20) for treadmills (18) and other platforms and devices therefor which exhibit controllability of the impact condition of the platform, such as a treadmill deck (36). In the treadmill application, user-selectable damping/stiffness is provided to simulate variable track conditions, such as pavement, rubber, grass, gravel, sand, and the like. The controllable suspension system (20) comprises spring mounts (40) or the like or a flexible deck (36) for allowing movement of the deck (36) relative to the frame (22) at a contact location (29) due to impact and a controllable device such as an Electrorheological (ER) device, Electrophoretic (EP) device, Electromechanical Hydraulic (Semi-Active) device, controllable mounting, or a Magnetorheological (MR) device, such as an MR brake (42a, 42a, 42b), MR damper (42d), or MR mount (42c, 42e, 42f) interconnecting between the frame (22) and platform (36) to provide the user-variable impact restraint.

Abstract: A magnetorheological fluid that includes a carrier component and a magnetizable particle component wherein the magnetizable particle component has a fractional packing density of at least 0.50 prior to formulation into the magnetorheological fluid. Use of this magnetorheological fluid can increase the force output of a magnetorheological device without increasing the viscosity of the fluid because the particle volume concentration in a working gap of the device increases when a magnetic field is applied.

Abstract: A controllable vibration apparatus having an electrical connection to a controllable valve made through a single-strand electrical conductor. In one embodiment, the piston and rod are preferably used as the source of ground or return electrical path. An axially compressed sealing element provides radial sealing against the conductor. An accumulator including a flexible diaphragm provides separation of fluid and accumulator chambers. In magnetorheological (MR) fluid dampers, a special sealing system including a relationship between piston rod surface finish and particle size is provided. A surface treated metal bushing is used with a lip seal to prevent escape of fluid and support side loads. The controllable valve can be formed from top and bottom pole pieces spaced from an outer ring to define a passageway. The pole and ring are preferably secured together by non-magnetic bridging elements. Preferably, the coil assembly is configured with integral axially-extending pins for ease of connection.

Abstract: A controllable brake (20) including a rotor (28) supported by a shaft (30) which is rotatably supported by bushings (42) received in housing (22). A coil assembly (48) creates a magnetic field within a pole piece (32), which is preferably manufactured from a powdered metal material, which preferably has a density of between about 6.8 and 7.0 gm/cm. A magnetically-soft medium is contained within first and second gaps (86, 88) located between pole piece (32) and rotor (28). In one aspect, a magnetic saturation zone (25) reduces the propensity of magnetizing the shaft (30). In another, the pole halves (24, 26) are received in radially-spaced pole pockets (37) formed in the housing (22) and include an axial bias spring (70) to ensure intimate contact. In another aspect, a lip projection (76) traps fluid (23) between the lip projection (76) and shaft (30) and minimizes fluid exposure to the shaft seal (44). In another aspect, cooling fins (55) or a projection (53) restrains rotation of the housing (22).

Abstract: The invention relates to magnetorheological (MR) fluid devices and the process of controlling the force in exercise equipment by utilizing the MR fluid devices. The MR fluid devices include rotary and linear acting varieties and are useful for controlled forces in exercise bicycles, recumbent exercisers, ski machines, rowing machines, and stair stepper machines. The rotary MR fluid device is comprised of a rotor supported by bearings and received within a housing. An MR fluid is received adjacent the rotor and within a cavity in the housing and the MR fluid is controlled by an applied magnetic field to vary the operating torque resistance. Spring biasing the rotor allows for relaxed tolerances. Optimization of the Ri/Ro ratio is described which reduces the size and weight of the device. The linear acting version utilizes simple extensible pumps and an external MR fluid valve to provide a modularized system.

Abstract: A portable controllable fluid device (20a) for rehabilitation of injured limbs, appendages and joints (33a). The rehabilitation device (20a) includes a first bracket (22a) for fixedly securing to a first body part, such as a lower leg (25), a second bracket (24a) for fixedly securing to a second body part, such as a foot (26), and a controllable fluid brake (27a) such as a magnetorheological fluid brake including a magnetorheological fluid contained therein having a carrier fluid and disbursed magnetic particles, attached between the first bracket (22a) and second bracket (24a). The controllable fluid brake (27a), preferably acts in a rotary fashion and provides resistive forces about an axis adjacent said body joint (33a) to exercise the muscles upon movement of said first bracket (22a) relative to said second bracket (24a) resulting from movement of the user's first body part relative to the second body part.

Abstract: A controllable fluid device (20) for rehabilitation of injured or weakened complex appendages such as the hands and feet. The controllable fluid device (20)includes a reservoir (34)which contains a sufficient amount of controllable fluid (52)such as a Magnetorheological (MR) fluid. A magnetic field generator (36)provides the magnetic field (H) which is applied to the controllable fluid (52) by a magnetic circuit (60). In one aspect, an electromagnet including a coil (58) and core (54) provides the magnetic field (H). The intensity of the magnetic field is controlled via a controller (38). In another aspect, the magnetic field (H) is provided by a permanent magnet (44) and a mechanical shunt mechanism (42) is used to vary the magnetic field intensity. Other embodiments include a heater unit (66) with optional thermostat (74).

Abstract: A magnetorheological material that includes magnetic particles; at least one water-soluble suspending agent selected from the group consisting of cellulose ether and biosynthetic gum; and water. The material can have a high particle loading, minimizes waste disposal problems, and can be produced at a lower cost relative to magnetorheological materials that include hydrophobic-oil type fluids as a carrier fluid.