Moving coil direct current reciprocating motor

Claim 2

A reciprocating apparatus comprising: a. shaft means for connection to a working element; b. resilient means operative for biasing such shaft in an opposite direction from a displaced position toward an initial position; c. the force exerted by said resilient means when said shaft is at the displaced position being at least as great as the force required to drive the working element in the opposite direction from the displaced position toward the initial position; d. a coil carried by said shaft means; e. a magnetic structure including an air gap in which the coil moves rectilinearly; f. control means responsive to the back EMF generated in the coil for selectively supplying unidirectional current to said coil of a polarity to produce movement of the working element in the one direction from the initial position to the displaced position and comprising a first transistor connected by its emitter and collector electrodes in series with said coil and a source of d.c. supply voltage, a reactance means, a second transistor, means responsive to the potential appearing at one of the emitter and collector electrodes of the first transistor for controlling the conductivity state of the second transistor for controlling the state of charge of the reactance means and means responsive to the state of charge of the reactance means for controlling the conductivity of The first transistor. g. the force produced as a result of interaction between the magnetic field in the air gap of the magnetic structure and the magnetic field of the coil resulting from the flow of the unidirectional current when the working element is moved in said one direction being at least as great as the sum of the force exerted by the resilient means in the opposite direction and the force required to drive the working element in the one direction.

Claim 3

Apparatus as defined in claim 1 wherein the resilient means is a compressible load.

Claim 4

Apparatus as defined in claim 1 wherein the resilient means is a spring.

Claim 5

Apparatus as defined in claim 1 wherein the shaft is connected to the working element through a lever arrangement.

Claim 6

Apparatus as defined in claim 1 wherein the force exerted by the resilient means varies from a first level at the displaced position to a lesser second level at the initial position and the control means supplies a greater flow of current through the coil at the initial position when movement of the coil in the opposite direction stops upon the force exerted by the element becoming equal to the force exerted by the spring in the initial position and until movement in the one direction stops upon the force exerted by the coil becoming equal to the sum of the forces exerted by the resilient means in the displaced position and the force exerted by the working element as the coil moves in the one direction than the flow of current during movement of the coil in the opposite direction.

Claim 7

Apparatus as defined in claim 1 wherein the working element is of a character such that the force required to drive the working element in the one direction is greater than the force required to drive the element in the opposite direction.

Claim 8

Apparatus as defined in claim 1 wherein the resilient means biases the coil away from the magnetic structure.

Claim 9

Apparatus as defined in claim 6 wherein the working element is a saw blade.

Claim 10

Apparatus as defined in claim 6 wherein the working element is a knife blade.

Claim 11

Apparatus as defined in claim 6 wherein the working element is a pump piston and the resilient means is a fluid compressed by the pump piston.

Claim 12

A motor as defined in claim 1 further including means for connecting the base electrode of said second transistor to one of the emitter and collector electrodes of the first transistor.

Claim 13

A motor as defined in claim 1 wherein said reactance means is a capacitor.

Claim 14

A motor as defined in claim 1 wherein said reactance means is a capacitor and including means connecting said second transistor by its emitter electrode in a discharge path for said capacitor and means for supplying base current to said first transistor as said capacitor is charged.

Claim 15

A motor as defined in claim 15 wherein said means for supplying includes a third transistor having base, emitter and collector electrodes and means connecting said third transistor to amplify the charge current of said capacitor and to apply the amplified current to drive said first transistor.

Claim 16

A motor as defined in claim 1 wherein the potential appearing at the one electrode varies as a function of the back EMF generated as said coil moves in a magnetic field.

Claim 17

A direct current motor as defined in claim 1 wherein said reactance means is a capacitor having two terminals and further including means connecting one terminal of the capacitor to one of the emitter and the collector electrodes of the second transistor and means connected to the capacitor terminals for providing charge and discharge paths for said capacitor whereby the charge on the capacitor varies as a function of the potential appearing at the one electrode of the second transistor.

Claim 18

A direct current motor as defined in claim 16 wherein the means connected to the capacitor terminals for providing a charge path for said capacitor includes the base-emitter circuit of one of a third transistor and said first transistor.

Claim 19

A direct current motor as defined in claim 16 wherein the potential appearing at the one electrode varies as a function of the conductivity state of the second transistor and further including means connected to the other terminal of the capacitor for supplying base current to the first transistor as said capacitor is charged.

Claim 20

A motor as defined in claim 1 further including resilient means for limiting the traverse of the shaft when current is supplied to said coil.

Claim 21

A motor as defined in claim 1 further including additional resilient means for controlling the shaft excursion.

Claim 22

A motor as defined in claim 20 wherein additional the resilient means includes a second spring effective at the end of the traverse of the shaft in the one direction to limit movement, said second spring being stronger than the first mentioned resilient means.

Claim 23

A reciprocating apparatus comprising: a. shaft means for connection to a working element; b. resilient means operative for biasing such shaft in an opposite direction from a displaced position toward an initial position; c. the force exerted by said resilient means when said shaft is at the displaced position being at least as great as the force required to drive the working element in the opposite direction from the displaced position toward the initial position; d. a coil carried by said shaft means; e. a magnetic structure including an air gap in which the coil moves rectilinearly; f. control means responsive to the back EMF generated in the coil for selectively supplying unidirectional current to said coil of a polarity to produce movement of the working element in the one direction from the initial position to the displaced position and comprising: a first transistor connected by its emitter and collector electrodes in series with said coil and a source of d.c. supply voltage, a reactance means, a second transistor, means responsive to the potential appearing at one of the emitter and collector electrodes of the first transistor for controlling the conductivity state of the second transistor for controlling the state of charge of the reactance means and means responsive to the state of charge of the reactance means for controlling the conductivity of the first transistor; g. the force produced as a result of interaction between the magnetic field in the air gap of the magnetic structure and the magnetic field of the coil resulting from the flow of the unidirectional current when the working element is moved in the said one direction being at least as great as the sum of the force exerted by the resilient means in the opposite direction and the force required to drive the working element in the one direction; h. the force exerted by the resilient means being variable from a first level at the displaced position to a lesser second level at the initial position; and i. said control means providing a flow of current through the coil which is greater than that provided as the coil moved in the opposite direction at the initial position when movement of the coil in the opposite direction stops upon the force exerted by the element becoming equal to the force exerted by the spring in the initial position and at least until movement in the one direction stops upon the force exerted by the coil becoming equal to the sum of the forces exerted by the resilient means in the displaced position and the force exerted by the working element as the coil moves in the one direction.

Claim 24

A reciprocating apparatus comprising: a. shaft means for connection to a working element; b. resilient means operative for biasing such shaft in an opposite direction from a displaced position toward an initial position; c. the force exerted by said resilient means when said shaft is at the displaced position being at least as great as the force required to drive the working element in the opposite direction from the displaced position toward the initial position; d. a coil carried by said shaft means; e. a magnetic structure including an air gap in which the coil moves rectilinearly; f. control means responsive to the back EMF generated in the coil for selectively supplying unidirectional current to said coil of a polarity to produce movement of the working element in the one direction from the initial position to the displaced position and comprising: a first transistor connected by its emitter and collector electrodes in series with said coil and a source of d.c. supply voltage, a reactance means, a second transistor, means responsive to the potential appearing at one of the emitter and collector electrodes of the first transistor for controlling the conductivity state of the second transistor for controlling the state of charge of the reactance means and means responsive to the state of charge of the reactance means for controlling the conductivity of the first transistor; g. the force produced as a result of interaction between the magnetic field in the air gap of the magnetic structure and the magnetic field of the coil resulting from the flow of the unidirectional current when the working element is moved in the said one direction being at least as great as the sum of the force exerted by the resilient means in the opposite direction and the force required to drive the working element in the one direction; h. the force exerted by the resilient means being variable from a first level at the displaced position to a lesser second level at the initial position; and i. said control means providing a flow of current through the coil which is greater than that provided as the coil moved in the opposite direction at the initial position when movement of the coil in the opposite direction stops upon the force exerted by the element becoming equal to the force exerted by the spring in the initial position and at least until movement in the one direction stops upon the force exerted by the coil becoming equal to the sum of the forces exerted by the resilient means in the displaced position and the force exerted by the working element as the coil moves in the one direction.

Claim 25

Apparatus as defined in claim 22 wherein the resilient means is a compressible load.

Claim 26

Apparatus as defined in claim 22 wherein the resilient means is a spring.

Claim 27

Apparatus as defined in claim 22 further including additional resilient means for controlling the shaft excursion.