US 5,910,090 AGranted

DC drive positioning system

AssigneeRiverwood International Corporation

InventorCarl J. Taute

Life of this patent

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Abstract

An apparatus for positioning a guide slidably mounted on a machine wherein the guide is driven by a lead screw turned by a DC motor through a worm drive gearhead. The DC motor is controlled by a programmable logic controller (PLC) with input from an operator interface and feedback from a hollow shaft encoder attached directly to a shaft extending from the lead screw. Ladder logic programming in the PLC directs the motor to run or stop based on comparing a target position for the guide with the current position based on electrical signals from said encoder. A home position for each guide corresponds to the guide's position when it has moved fully outward encountering an outward stop. The programming also allows manual jogging of the guide through the operator interface. The programming takes up mechanical backlash in the apparatus on each move by overshooting the target position a predetermined amount when a move is made in an outward direction. Moves in an inward direction proceed directly to the target position. A changeover cycle moves all guides to positions selected from previously stored positions.

Claims23

Dependent claims

A DC drive powered apparatus for automatically positioning a movable guide on a packaging machine, comprising:

(a) at least one rail attached to said packaging machine;
(b) a guide slidably attached to said at least one rail;
(c) a rotatable lead screw attached to said machine and oriented parallel with said at least one rail;
(d) a nut fixedly attached to said guide and threadably engaged with said lead screw;
(e) an encoder mechanically coupled to said lead screw and electrically connected to a programmable logic controller to provide feedback to said programmable logic controller regarding rotation of said lead screw;
(f) a DC electric motor having an output shaft, said motor running in a forward or reverse direction;
(g) a DC drive electrically connected to said DC motor;
(h) a gearbox having a worm drive input, a worm gear, and an output shaft, said worm drive input being attached to said output shaft of said motor, said output shaft of said gearbox having reduced speed and increased torque relative to said output shaft of said motor;
(i) a mechanical coupling connecting said output shaft of said gearbox and said lead screw;
(j) an outward mechanical stop on said machine interacting with said nut and said lead screw to mechanically limit outward travel of said nut on said lead screw, said stop providing a home position of said guide for said programmable logic controller when said outward travel of said nut is limited by said stop;
(j) a programmable logic controller electrically connected to said encoder and to said DC drive, said programmable logic controller containing programming steps to direct said motor to run or stop to move said guide, said programming steps including at least one step which directs said motor to run or stop based on comparing a current position of said guide with a target position, said current position being calculated based on electrical signals from said encoder, said programming steps including at least one step which allows manual jogging of said guide by incrementally changing said target position, said programming steps including at least one step to define said home position for said guide, said programming steps including at least one step to take up mechanical backlash in said apparatus by overshooting of said target position by a predetermined amount when a move is made in an outward direction;
and
(k) an operator interface electrically connected to said programmable logic controller, whereby said motor runs to turn said lead screw to cause said guide to slide on said at least one rail by commands from said programmable logic controller based on input from said encoder and said operator interface to position said guide along said at least one rail.

10 more elements

An apparatus for positioning a element on a machine, comprising:

(a) an element movably attached on said machine;
(b) a direct current powered actuation mechanism connected to said element, said actuation mechanism selectively moving said element to a desired position, wherein said direct current powered actuation mechanism includes a DC electric motor having a rotating output shaft, said motor running in a forward direction and a reverse direction, and wherein said direct current powered actuation mechanism further includes:
a DC drive electrically connected between said DC electric motor and said programmable control device, said DC drive selectively running and stopping said DC electric motor based on signals it receives from said programmable control device,
a gearbox mechanically coupled to said output shaft of said electric motor, said gearbox having an output shaft with reduced speed and increased torque relative to said shaft of said electric motor, and
a rotatable lead screw mechanically coupled to said output shaft of said gear box and a nut threadably engaging said lead screw, said nut being attached to said element, whereby as said lead screw is rotated by said electric motor and said gearbox, said nut travels along said lead screw to move said element to said target position;
and
(c) a programmable control device in electrical communication with said actuation mechanism, said programmable control device having programming steps, said programming steps directing said actuation mechanism to move said element to a target position said apparatus further comprising a mechanical coupling connecting said gearbox and said lead screw, wherein said coupling includes a first timing pulley connected to said lead screw, a second timing pulley attached to said output of said gearbox, and a timing belt operating between said first pulley and said second pulley to transfer torque between said second pulley and said first pulley.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 08/868,204Filed 3 Jun 1997 · continuation in part
Priority: 30 May 1997
Granted: 8 Jun 1999
Term ends: Not estimatedThe source records don’t support an estimate.

Classification17 codes

B65B 59/005
Arrangements to enable machines to handle articles of different sizes, to produce packages of different sizes, to vary the contents of packages…
B65B 21/242
Enclosing bottles in wrappers: in collapsed carton sleeves
B65B 43/225
By rollers: specially adapted for carton blanks
B65B 43/265
Opening or distending bags; Opening, erecting, or setting-up boxes, cartons, or carton blanks: opening, erecting or setting-up boxes, cartons or…