Tri-tech Corporation

Tritex Corporation

Robert Pulford, Jr

Brian Peterson

Adam Szepesi

Richard Donnelly

A method of providing axially alternating N and S poles in a portion of an axially extending, cylindrical, smooth shaft for a linear stepper motor and a method of manufacturing a magnetizing fixture are provided. A magnetizing fixture is provided including a hollow cylindrical mandrel formed from a non-magnetic material, a single conductive wire serially disposed in parallel, circumferential channels defined in an outer surface of the mandrel, and a central bore defined axially and centrally through the mandrel. The portion of the shaft is inserted in the central bore and a direct current is provided through the wire to magnetize alternating N and S poles along the cylindrical shaft. The wire may be placed in the parallel, circumferential channels such that the direction of flow of a direct current in one channel is in the opposite direction of the flow in the adjacent channels.

Method of magnetizing the shaft of a linear stepper motor

In a preferred embodiment, a fixture for magnetizing axially alternating N and S poles defined circumferentially in a portion of an outer periphery of an axially extending, cylindrical, smooth shaft, the fixture including: a hollow cylindrical mandrel formed from a non-magnetic, non-electrically-conducting material; a conductive wire disposed in parallel, circumferential channels defined in an outer surface of the mandrel; a potting compound surrounding the mandrel to secure the conductive wire in place; and a central bore defined axially and centrally through the mandrel and exposing or nearly exposing the conductive wire; and the central bore being sized to accept axially inserted therein the portion of the axially extending, cylindrical, smooth shaft. Methods of using and manufacturing the fixture are also provided.

Fixture for magnetization of a shaft for a linear stepper motor

In a preferred embodiment, linear stepper motor, comprising; an annular stator structure; an axially extending, cylindrical, permanent magnet shaft extending coaxially through said annular stator structure; and the axially extending, cylindrical, permanent magnet shaft having a smooth external surface along a portion thereof with axially alternating N and S poles defined circumferentially in an outer periphery of the portion of the axially extending, cylindrical, permanent magnet shaft. The present invention also provides a method of magnetizing the shaft of such a motor and a fixture and method of manufacturing the fixture therefor.

Linear stepper motor

In a preferred embodiment, a linear/rotary motor, including: a housing; an output shaft extending from the housing; a rotary motor disposed within the housing, the output shaft being given rotational motion by the rotary motor; a linear motor disposed within the housing; a linear shaft axially moveable by the linear motor; and a coupling to join the linear shaft and the output shaft to permit transfer of axial motion from the linear shaft to the output shaft but to isolate rotational motion of the output shaft from the linear shaft.

Linear/rotary motor and method of use

In a preferred embodiment, a stepper motor control, including: a driver to drive the stepper rotor; a detector to detect a commanded step rate signal provided to the driver and to provide an output signal proportional thereto; a power control, responsive to the output signal, to provide driving power to the driver, and to increase voltage to the driver in proportion to an increase in magnitude of the output signal; and an over-current protection circuit that becomes active above a predetermined motor current level and above a predetermined commanded step rate. Voltage control can be effected either on the drive board or by controlling the power supply. An additional feature provides over-current protection for the stepper motor during a lock rotor (stall) condition. The stepper motor control produces very low levels of EMI/RFI as compared with PWM current control (chopper) drives.

Stepper motor control

A flexible joint for first and second rotating members, including: a hub fixedly connected to a proximal end of the first rotating member at a first end of the hub; the hub being constructed for the insertion in a second, opposite end of the hub of a proximal end of the second rotating member, the proximal end of the second rotating member being moveable within the hub such that a distal end of the second rotating member may move axially with respect to the first rotating member and/or may move radially away from a major axis of the first rotating member; and a spring disposed between an end face of the proximal end of the second rotating member and an inner face of the hub to bias the second rotating member axially away from the hub and the first rotating member, strength of the spring determining the ease with which the distal end of the second rotating member may move.

Spring biased universal joint

In a preferred embodiment, a linear positioning device, including: a frame member; an electric motor disposed to selectively move axially back and forth in the frame member; carriage apparatus attached to the electric motor; and apparatus to guide the motor in axial movement and to prevent radial movement thereof. In a further aspect of the invention, there is provided a frame for a linear positioning device, including: a horizontal base plate; vertical end plates for attachment to ends of the base plate; the base plate including a first groove defined in the surface thereof for the mounting therein of a guide rail for a moving member; and the base plate is cut from an extrusion which includes the first groove, without the machining thereof. In another aspect of the invention, there is provided, in a linear positioning device, having the front end plate of an electric motor as an end plate of the device. In an additional aspect of the invention, there is provided, in a positioning device, having an electric motor fixedly mounted to an end plate of the device.

Growing community of inventors

Wolcott, CT, United States of America

Robert Pulford, Jr