Abstract: An electromagnetically actuated friction clutch includes a rotatably driven input gear. A rotatable armature is connected to the input gear and includes a friction face and nitrocarburized outer surfaces. A pole piece has a pole face for engaging the friction face of the armature and nitrocarburized outer surfaces. An electromagnet generates an electromagnetic field to shift the armature from a disengaged position to an engaged position wherein the friction face of the armature and the pole face of the pole piece are frictionally engaged. An output shaft is driven by the input gear when the armature is in the engaged position. The nitrocarburized outer surfaces of the armature and the pole piece resist wear, while interior portions of the armature and pole piece direct magnetic flux flow along a desired path.

Abstract: A soft start electromagnetic coupling has a driven member and a driving member that are coupled together in response to a magnetic flux produced by a direct current flow through a winding on the clutch. When the members are coupled by an electromagnetic flux, they may slip relative to reach other during starting, when the load on the coupling changes or when the accessory driven by the coupling freezes or becomes jammed. Relative slippage of the members produces an alternating current component in the direct current flow that is detected to indicate the slippage. The presence of an alternating current component can be sensed through a rectifier or frequency filter. Preferably, the presence of a persistent alternating current component causes a switch to open, interrupting the flow of direct current to the coupling.

Abstract: The rotor and armature of an electromagnetic clutch are formed with multiple regions of high magnetic reluctance defined by slots which are shaped and located such that the radial relation between the slots of the rotor and the slots of the armature changes as one member rotates relative to the other. As a result, the flux density across the air gap between the rotor and the armature varies when the armature slips relative to the rotor during initial engagement of the two. This lowers the average torque transmitted by the rotor to the armature and allows the clutch to engage gradually or with a soft-start before building up to full torque.

Abstract: A swivel coupling for connection between a dental handpiece and a supply hose. The coupling includes a lamp in its handpiece connector portion, and an annular commutator in its hose connector portion. The lamp base is in sliding contact with the commutator to permit swiveling of handpiece portion relative to hose portion. Exhaust air from the handpiece turbine meter passes over and around the lamp and its surrounding structure for heat removal.

Abstract: A hose having multiple conduits or conductors for transmitting drive air, water, chip air, light and/or electricity to a turbine-driven dental handpiece or other tool and for conveying exhaust air away from that handpiece, such hose being equipped with a plurality of swivel connectors for permitting the handpiece to be rotated a limited amount in each direction about its longitudinal axis with no objectionable restraint imposed, or restorative force exerted, by the conduits as they twist about each other during such handpiece rotation. In each disclosed embodiment, a plurality of the conduits have at least adjacent portions unattached to each other and individually provided with separate swivel connections.

Abstract: A swivel coupling for connecting a hose containing a drive air conduit, a secondary air conduit, a water conduit and an optical fiber conduit to a handpiece, such as a dental handpiece, having like conduits. The coupling permits unlimited swiveling, and efficient use of space by means of concentric annular passages in a central swivel tube.

Abstract: The field shell of an electromagnet is formed with angularly spaced flanges which define a magnetic pole and which also serve as a mounting hub for a coil assembly consisting of a bobbin and a multiple turn winding. Resilient fingers on the bobbin snap into openings in the flanges to hold the bobbin and the shell in assembled relationship. Tabs are located between and project inwardly from the flanges and are used to mount the shell in a fixed position.

Abstract: The magnet core of an electromagnetic clutch is substantially J-shaped in radial cross-section and includes an outer pole ring which is spaced radially outwardly from and which only partially surrounds the outer pole ring of the rotor of the clutch. The controlled transfer of flux between the core and the rotor occurs both in a radial direction and in an axial direction.

Abstract: A modular multi-function selector valve assembly for controlling the flow of fluids for a plurality of dental handpieces. Each of the modules is functionally associated with one of such handpieces and, in response to the absence or presence of pilot air pressure, the multiple valves of that module simultaneously open or close passages for drive air, chip air, and water, as well as for other fluids such as exhaust air and gauge air. The modules are disposed in side-by-side relation with each other and each module is transversely divided into control and valve sections. A plurality of main and secondary flow passages are formed in the sections, and one side of each section is also provided with at least one channel communicating with certain of such passages.

Abstract: A speed control system for dental handpieces in which a sleeve or tube of pliable material defines an elongated deformable passage. The passage communicates at one end with a source of gas (air) under pressure and, at its opposite end, is vented to discharge a continuous stream of gas whenever the unit is in operation. When the resilient sleeve is squeezed anywhere along its length, back pressure is created which acts upon a pressure-responsive pilot valve, the pilot valve in turn regulating the speed of the dental handpiece in accordance with the amount of back pressure developed.

Abstract: A method and apparatus for testing the integrity of spot welds made by a welding machine without destroying the manufactured parts being produced, said method and apparatus including welding together a pair of angle members made from the same sheet material as the parts being manufactured to form a "T-shaped" test specimen with the outwardly extending cross arm of this "T" forming attachment portions and providing a testing tool constructed and arranged to pull apart the welded together portions of the angles and test the integrity of the weld with a minimum of force being applied thereto.