Electromagnetic vibrator
AssigneeRexnord Inc.
InventorMaynard Charles Yeasting
Life of this patent
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Abstract
An electromagnetic vibrator that is resonant at a frequency below one third of the frequency of an alternating current power source is driven by a linear electromagnetic motor, the airgap of which varies with the vibration of the vibrator, in which motor current flow from the power source is established during the first half cycle of the power line voltage that occurs after the airgap is a maximum, is maintained independently of the power source during at least a major portion of the next half cycle, and is reduced to zero during the next following half cycle of power source voltage. Preferably two electromagnetic motors are employed, one for each direction of relative motion between the vibrator parts.
Claims8
In an electromagnetic vibrator comprising a work member to be vibrated, an exciter member, and resilient means connecting the members to form a vibratory system, a drive comprising an electromagnetic motor having a part on each of said members and a control for energizing said motor, said control comprising means for energizing said motor during at least part of a first half cycle of an alternating current power line voltage cycle, means for deenergizing the motor during a subsequent half cycle, and synchronizing means adapted to select as said first half cycle the first half cycle of the power line voltage that starts when said resilient means are near maximum extension in a selected direction.
An electromagnetic vibrator comprising a work member to be vibrated, an exciter member, resilient means connecting the members to form a vibratory system, an electromagnetic motor having a part attached to each member for vibrating said members, said motor parts being separated by an air gap that varies with the vibration of the members, a vibration pickup attached to at least one of said members for generating an electrical signal corresponding to the vibration of the member, semiconductor switching means adapted to connect said electromagnetic motor to an alternating current power line, and logic means connected to and adapted to control said switching means, said logic means being connected to and responsive to said vibration pickup and to the power line and arranged to energize the switching means during at least part of each nth half cycle of the power line voltage in the absence of a signal from the pickup and during at least part of the first half cycle of the power line voltage that begins while said air gap is near maximum length in response to signals from said pickup.
Dependencies are inferred from the claim text.