Ledex, Inc.

Impact Devices Incorporated

Kenneth L Roy

Philip E Fugate

William D Sadgebury

Disclosed is a printing solenoid specifically adapted and improved for the printing of Braille dots and in particular interpoint Braille. A plunger and printing shaft are fixably mounted together and the combination mounted for slidable movement in a rear end cap and in a molded insert bearing between energized and deenergized positions. The plunger/printing shaft combination are located within a bobbin having an electric coil wound thereon. A tubular case encloses the coil and mounts a front bushing which in turn mounts the molded insert bearing. A rear flux washer is held in place between the bobbin by the rear end cap which is retained within the rear portion of the tubular case. During energization, the plunger and printing shaft combination move such that the shaft strikes a piece of paper to be imprinted with a Braille dot. Depending upon whether the dot is to extend away from the solenoid or towards the solenoid, an embossing ball or an embossing recess is used on the end of the printing shaft. An internal return spring moves the plunger/printing shaft combination back to its deenergized position. A high degree of printing accuracy is achieved by slidably mounting the plunger/printing shaft combination in bearings which are separate from the bobbin coil assembly. The end cap is responsive to a torque applying device, and through the rear flux washer and the bobbin, torque can be applied to the bushing to aid in inserting or removing the solenoid from a dense solenoid array.

Braille printing solenoid housing

A high speed axial-type printing solenoid includes a rebound and energy absorbing arrangement which employs a block of energy-absorbing 'dead' elastomeric material held in a partially compressed state by an impact plate. The impact plate is mounted to engage and position the plunger or armature at a rest position and to transmit impact forces to the partially compressed block of elastomeric material.

Print wire solenoid

Low cost tubular solenoids are formed with a drawn case in which the pole portion forming the base of the solenoid is defined as an integral inwardly extending part of the case. A coil bobbin is formed by the injection molding of plastic material and is provided with an integral wall which is positioned in abutting relation to the inside surface of the pole portion, thereby forming a stop surface for the solenoid plunger and effectively spacing the plunger from the base. The plunger is guided on the internal surfaces of the bobbin and in one embodiment, a spun hollow sheet metal bushing is captured by the case in telescopic relation to the bobbin, and is formed with threads which receive thereon a sheet metal retaining nut. In another embodiment of the invention, a washer is threaded onto an axial extension portion of the bobbin, and the open end of the case is crimped onto an annular groove formed on the washer. In a further embodiment, the washer is injected molded in place on the bobbin. Terminal leads are molded on the bobbin and extend through apertures formed in a bobbin extension elimating the need for the placement of coil lead-in wires.

Tubular solenoid

A print wire solenoid for high-speed operation is made with two major components or subassemblies. The first is a plastic injected unitary bobbin or stator assembly which incorporates a core ring and a core, and a stator which forms a bobbin for receiving an electric coil. The parts in the stator are positioned and molded to a datum surface. The second major subcomponent is a unitary armature assembly which incorporates an armature, a retraction spring, and a print wire, all anchored to a plastic body. These parts are likewise positioned with respect to a datum surface. The stator assembly and armature assembly are retained within a drawn metal case, and a rebound disc is positioned within the case and locates the datum surface of the armature assembly in the same plane as the datum surface of the stator assembly so as to define an accurate working air gap.

Growing community of inventors

Centerville, OH, United States of America

Kenneth L Roy