Machine tool with servo drive mechanism

• US 20020010991A1
• Filed: 05/23/2001
• Published: 01/31/2002
• Est. Priority Date: 06/27/2000
• Status: Active Grant

• Current Assignee: Davenport Machine, Inc.
• Original Assignee: Davenport Industries, LLC (Brinkman International Group, Inc.)
• Inventors: Patridge, Steven K., Muscarella, Patrick L.
• Granted Patent: US 6,421,895 B2
• Time in Patent Office: Days
• US Class Current: 29/38B
• CPC Class Codes: B23Q 15/013 Control or regulation of feed movement B23Q15/12 takes precedence
• CPC Class Codes: B23Q 39/044 having at least one tool station cooperating with each work holder, e.g. multi-spindle lathes
• CPC Class Codes: B23Q 5/10 driven essentially by electrical means
• CPC Class Codes: B23Q 5/28 Electric drives
• CPC Class Codes: B23Q 5/341 cam-operated
• CPC Class Codes: B23Q 5/36 in which a servomotor forms an essential element
• CPC Class Codes: G05B 2219/50233 Synchonize time-dependent with electronic cam data
• CPC Class Codes: Y02P 70/10 Greenhouse gas [GHG] capture, material saving, heat recovery or other energy efficient measures, e.g. motor control, characterised by manufacturing processes, e.g. for rolling metal or metal working
• CPC Class Codes: Y10T 29/5128 Rotary work - vertical axis
• CPC Class Codes: Y10T 29/5129 Rotary work - horizontal axis
• CPC Class Codes: Y10T 29/513 Stationary work
• CPC Class Codes: Y10T 82/2502 with program control
• CPC Class Codes: Y10T 82/2524 Multiple

Abstract

A machine tool has a cam shaft and indexing drive mechanism which is driven by a servomotor and is therefore adapted for operation within a wide range of operational parameters. An encoder mechanism provides feedback to the servo drive mechanism to effect operational control. The machine tool further comprises a variable frequency drive motor which operates the spindles of the machine tool independently of the cam shaft and indexing drive. A servo-operated threading mechanism is operable at one or more workstations of the machine tool to provide threading of parts manufactured thereby. A computer control system controls and monitors the entire operation of the machine tool.

Claims

1. In a machine tool of the type wherein lengths of bar stock are rotated about longitudinal axes and machining tools are actuated by cams to engage the machining tools with the rotating bar stock to effect machining thereof, the improvement comprising:

a plurality of working spindles each for receiving a length of bar stock therein and each defining an axis of rotation of its respective length of bar stock;

a variable frequency spindle drive motor;

a gear train operatively connecting the variable speed spindle drive motor to the working spindles to effect rotation of the working spindles and the lengths of bar stock carried thereby about the axes of rotation defined by the working spindles;

a first cam shaft extending parallel to the axes of rotation defined by the working spindles;

a plurality of first cams mounted on the first cam shaft for rotation thereby to cause operation of first machining tools thereby machining the lengths of bar stock carried by the working spindles during rotation thereof under the action of the variable frequency spindle drive motor;

an indexing mechanism driven by the first cam shaft for sequentially indexing each of the working spindles through a plurality of workstations;

a second cam shaft extending perpendicularly to the axes of rotation defined by the working spindles;

a plurality of second cams mounted on the second cam shaft for rotation thereby to cause operation of second machining apparatus thereby machining the lengths of bar stock carried by the working spindles during rotation thereof under the action of the variable frequency spindle drive motor;

a servomotor;

a gear train operatively connecting the servomotor to the first and second cam shafts to effect rotation of the first and second cams and to effect operation of the indexing mechanism independently of the operation of the variable frequency spindle drive motor; and

a programmable logic controller for controlling the operation of the variable frequency spindle drive motor and the servomotor.

2. The improvement according to claim 1 further including an absolute encoder driven by the first cam shaft under the action of the servomotor for producing an output indicative of the operation of the servomotor and for directing the output to the programmable logic controller.

3. The improvement according to claim 2 further including a threading mechanism for performing machining of the lengths of bar stock and a servomotor for operating the threading mechanism under control of the programmable logic controller.