An injection device for administering a medical substance includes a helical spring having a coil that extends in an axial direction and has at least three windings, where two adjacent windings are non-detachably connected to one another at a point in the axial direction by means of a laser-welded connection. The helical spring and a method for producing the helical spring for use with the injection device are also provided.

A flywheel apparatus includes a damper, and a mass ring including a first surface facing a first side in an axial direction, a second surface facing a second side and a first circumferential surface facing an inner side in a radial direction. The apparatus includes a drive plate including a first wall portion including a third surface being in contact with the second surface, and a plurality of protruding portions, each of the plurality of protruding portions including an end surface configured to fit to the first circumferential surface. The drive plate is configured such that the mass ring is concentrically attachable to the drive plate by the fitting of the end surfaces and the first circumferential surface to each other.

Systems and a method for resisting a fluctuation in a value of a parameter relating to well equipment using a magnetorheological dampener system are described herein. The method includes continuously determining the value of the parameter relating to the well equipment, determining a fluctuation in the value of the parameter, and comparing the fluctuation in the value of the parameter to a preset limit. The method also includes energizing an electromagnet to increase a viscosity of a magnetorheological fluid (MRF) if the fluctuation exceeds the preset limit.

A multiple frequency vibration attenuation device comprises a mass portion and a spring portion and may attenuate vibrations at two or more different frequencies. The shape and mass of the mass portion is dependent on the spring rate and lateral bending rate of the spring and the frequencies that are desired to be attenuated. In an embodiment, two or more of the natural frequencies of the multiple frequency vibration attenuation device match the vibration frequencies of an aircraft system that are desired to be attenuated.

A bumper spring assembly having a one piece mandrel including an integral head piece is further configured with a cage assembly retained on the mandrel with a cage nut locked to the mandrel to obviate the need for pins, set screws, and the like, to provide a more robust assembly. In two embodiments the cage nut is locked to the mandrel in a swaging operation. Improved flow of fluids through and around the bumper spring assembly are also provided

A method for the production of a metal strip is provided. The method includes providing an amorphous metal strip having a first main surface and a second, opposing main surface. The first and/or the second main surface are treated with a wet-chemical etching process and/or a photochemical etching process.

A mass flow controller includes an inlet, a flow path in which fluid passes, a mass flow sensor configured to provide a signal corresponding to mass flow of the fluid through the flow path; a control valve configured to regulate a flow of the fluid out of an outlet of the mass flow controller; and a passive damping system coupled to the control valve and configured to dissipate fluid flow induced vibrations introduced by the control valve assembly. The passive damping system includes a damping pad between a receiver section of a valve base and a diaphragm backer. The passive damping system can also include a damping washer. The passive damping system can include one or more plunger balls between the damping pad and the valve base or one or more wave springs.

A method of making a carbon fiber wave spring includes forming a disc-shaped ring from prepreg carbon fibers. The disc-shaped ring is then formed into a desired wave shape. The disc-shaped ring in the wave shape is then cured to form a wave spring.

Disclosed is a ceiling type seismic impact buffer unit which may perform a buffering action of reducing vibration or the impact applied thereto attributable to earthquakes, typhoons, etc. without direct transmission of the vibration or the impact to a ceiling panel installed on a ceiling. The ceiling type seismic impact buffer unit includes a housing main body, a first coupling bolt, which is fixed into a coupling hole formed in the center of the upper surface of the housing main body and has a front end connected to an upper connection rod, a second coupling bolt, which is fixed to a sliding contactor through a sliding guide hole formed in the center of the lower surface of the housing main body and has a front end connected to a lower connection rod, and a restoring spring, which has upper and lower ends coupled to first and second fixing washers.

A damper device includes: a first rotating body rotating around a rotation shaft and receiving power transmitted from a flywheel; a second rotating body including a first plate receiving the power transmitted from the first rotating body and a second plate disposed to face the first plate and rotating integrally with the first plate; a third rotating body rotating relative to the second rotating body around the rotation shaft; a fastening body integrating the first and second plates at a position radially spaced apart from a position where the power is transmitted from the first rotating body to the first plate; and an elastic mechanism elastically interconnecting the second and third rotating bodies in a rotation direction. The first plate is provided with a restricting portion restricting relative rotation of the third rotating body beyond a predetermined torsion angle.