Monitorable and compensatable feedback tool and control system for a press using a solid tool backup element

• US 4,918,956 A
• Filed: 01/30/1989
• Issued: 04/24/1990
• Est. Priority Date: 08/27/1987
• Status: Expired due to Term

• Current Assignee: Minster Machine Company The Minster Oh
• Original Assignee: The Minster Machine Company (Nidec Corporation)
• Inventors: Schoch, Daniel A.
• Primary Examiner(s): NOT, DEFINED
• Application Number:
  US07/304,185
• Time in Patent Office: 449 Days
• Field of Search: 72/1, 72/19-21, 72/12, 72/34, 72/37, 72/446, 72/448, 72/452, 72/453.14, 72/465, 72/466, 267/119, 267/130, 100/257
• US Class Current: 72/21.1
• CPC Class Codes: B21D 51/383 scoring lines, tear strips or pulling tabs
• CPC Class Codes: B30B 15/0041 Control arrangements therefor
• CPC Class Codes: B30B 15/0094 Press load monitoring means B30B15/281 takes precedence

Abstract

A load control system and tool arrangements are disclosed for controlling the shutheight and back-up load on a mechanical press tool in response to a monitored or measured parameter indicative of press tool force or part quality, which monitored parameter is communicated to a controller for determination of a control signal to control a means for regulating the press tool back-up load and shutheight without interrupting press operations. The control system is operable to control a single station or multi station press and can be installed on either an individual press tool or the bolster or slide. The back-up load is controlled by a non-fluid, moveable mechanical tool back-up mechanism.

Claims

1. A method of monitoring and controlling a back-up load to at least one of an upper and lower tool in a press during the actuation of the tools on a workpiece comprising:

applying a variable back-up force to the one tool wherein the back-up force is effected at least during tool actuation,

sensing the back-up load at said one tool during actuation of the tools on the workpiece and producing a signal correlated to the sensed load;

comparing a predetermined reference load signal and said sensed signal and producing an output control signal as a function of said compared signals; and

controlling, in response to said control signal, the back-up load on said one tool by adjusting the position of a solid, non-fluid back-up element to increase or decrease resistance in a direction opposite to the direction of force applied by the other tool.

2. In a press having a slide and bolster to which is attached tooling comprising a plurality of die stations, each die station performing a separate forming operation on a workpiece passing through the press, a method of controlling quality of the formed workpiece comprising:

sensing the individual loads on the tooling in each of the die stations as the press is running and providing an indication of such loads,

comparing the sensed loads with desired loads, and

while the press is running, modifying the back-up loads applied to those die stations where the sensed loads differed from the desired loads to achieve desired load conditions by adjusting the position of a solid non-fluid back-up element to increase or decrease resistance in a direction opposite to the direction of force applied to the tooling during actuation of the press, the back-up loads for the die stations being modified independently of each other.

3. In a press having a slide and bolster to which is attached tooling comprising a plurality of die stations, each die station performing a separate forming operation on a workpiece passing through the press, a method of controlling quality of the formed workpiece comprising:

sensing the values of a plurality of predetermined dimensional parameters of the workpiece formed by the tooling that vary depending on the amount of force exerted on the workpiece by the tooling at the respective die stations,

comparing the sensed parameter values with desired parameter values, and

while the press is running, modifying the back-up loads applied to those die stations where the sensed parameter values differ from the desired parameter values to achieve desired parameter values by adjusting the position of a solid, non-fluid back-up element to increase or decrease resistance in a direction opposite to the direction of force applied to the tooling during actuation of the press, the back-up loads for the die stations being modified independently of each other.

4. A method for monitoring and controlling a back-up load to a back-up load means with at least one of an upper tool and lower tool in a press assembly, said back-up load means including a tool support, said upper tools and lower tools cooperating to define the shutheight therebetween, said method comprising:

exerting a variable force on the tool support to thereby provide a back-up load to said tool support;

sensing the back-up load at said at least one of an upper tool and lower tool as the tools form a workpiece and producing a signal correlated to the sensed load;

comparing a predetermined reference load signal and said sensed signal and producing an output control signal as a function of said compared signals; and

utilizing said output control signal to control automatically the variable force and the tool back-up load to elastically deform said tool support thereby varying said shutheight to thus control said tool load during forming of the workpiece.

5. The method of claim 4 wherein the press tooling comprises a plurality of die stations that perform different forming operations on the workpiece and including:

sensing a plurality of parameters of the workpiece that vary depending on the force exerted on the workpiece at the respective die stations, and

independently controlling the back-up loads at the die stations in response to the sensed parameters.

6. The method of claim 5 wherein the step of controlling comprises manually adjusting back-up force to the tooling.

7. A method for monitoring and controlling a back-up load to a tool means in a pres having a plurality of upper tools and a plurality of lower tools and a tool support having one of said plurality of upper and lower tools mounted thereon in a press assembly, said method comprising:

applying mechanical back-up force to said tool support to provide a back-up load to said plurality of tools thereon, the mechanical back-up force being applied by adjusting the position of a solid, non-fluid back-up element to increase or decrease resistance in a direction opposite the direction of force applied by the other tools;

sensing the back-up load at least at one of said tools and producing a signal correlated to the sensed load;

providing a display device;

comparing a predetermined reference load signal and said sensed signal and, producing and displaying an output control signal on a display device as a function of said compared signals; and

controlling said mechanical back-up force and said tool back-up load in response to said control signal.

8. In a press having a plurality of upper tools and lower tools, for performing forming operations on a workpiece passing through the press, which upper tools and lower tools define a shutheight therebetween, and a tool support, a method for controlling the shutheight and thus the back-up force applied to the workpiece, said method comprising:

applying a controllable mechanical back-up force to said tool support during the forming operations on said workpiece;

sensing a predetermined parameter of the workpiece formed by the tooling that varies depending upon the amount of force exerted on the workpiece by the tooling;

producing a sensed back-up load signal indicative of the force exerted on the workpiece that correlates to the value of the sensed parameter;

comparing the back-up load signal with a reference signal indicative of a back-up load correlative to a desired value of said parameter;

producing and displaying an output control signal indicative of said compared signals; and

varying said mechanical back-up force applied to said tool support to elastically deform said support thereby varying said shutheight and thus said back-up load at said tools.