The present invention relates generally to material roil uncoiling operation, such as in particular assemblies for uncoiling and straightening such as steel roll material prior to feeding into a press or other downstream stamping operation. More specifically, the present invention is concerned with a servo operated feed component of the assembly which operates in conjunction with the downstream located press in order to successively and repetitively grip, advance and release the uncoiled steel roll in a fashion which allows for the stamping or other material press operation to proceed without damage or marring of the uncoiled feed material. A further objective of the present assembly, process and software based medium is to provide for highly tuned and rapid grip and release of the uncoiled material roll, such as which occurs according to finely calculated dimensions factoring in the material thickness of the uncoiled sheet material, this facilitating more rapid and controlled transfer of the uncoiled sheet to the downstream press/stamping operation as well as improving accuracy of the more rapidly fed steel sheet into the successive press operation.
The prior art is well documented with numerous examples of press feed mechanisms, such typically including a transfer station positioned in communication with a metal stamping or like machine. The transfer station serves the purpose of aligning and feeding a metal sheet (typically unrolled from a feed drum) into the stamping or other material pressing operation.
To this end, the extending edges of the metal sheet typically include cutout apertures or the like through which engage traversable gripping fingers for moving the sheet along the feed mechanism and into the press operation. The press feed mechanism further includes an arrangement of driving/driven rollers, typically including a displaceable upper roller (often via some type of cam arrangement) moved into and out of contact with a lower roller, between which is communicated the steel sheet.
Disadvantages associated with known press feed mechanisms include the limited degree of inter-adjustability which can be established between the rollers, e.g. such resulting in the upper adjustable roller displacing into either of fully engaged or fully released contact relative to the lower roller and interposed sheet. The result of this is to slow the rate of sheet feed (or advance) between iterative stamping operations, thereby negatively impacting productivity.
Existing press feed assemblies utilize some form of cam feed associated with a drive roller and include each of the oscillating cam feed apparatus of Gentile, U.S. Pat. No. 4,316,569, the high speed cam roll lifter for a press feeder of Johnson, U.S. Pat. No. 4,144,990 and the adjustable input shaft for a press feed of Gentile, U.S. Pat. No. 4,449,658. Additional references of note include Waddington, U.S. Pat. No. 5,150,022 (servo controlled pilot release for a press feeder) and Gentile, U.S. Pat. No. 5,755,370 (press feed with infinitely variable stock material engagement spacing).
Such feed assemblies as described accordingly constitute a final component of a roll uncoiling operation and which handle the transfer the uncoiled and straightened material roll from the initial straightening operation to the downstream located press or stamping operation. As also above described, the feed assembly further typically includes at least one drive roller in close proximity to one or more additional rollers for gripping and advancing the uncoiled material in a manner consisting with the input requirements of the downstream press operation.
Traditional pilot release of feed rollers, also described in the relevant commercial art as “roller venting” can be actuated by one or more air cylinders of various bore size, such as in order to release an upper located feed roll from a corresponding lower feed roll, such further occurring upon lifting the full travel of the cylinder to allow for maximum material thickness clearance according to the machine capacity. In certain instances, the requirement of the air cylinder imparting a full (excessive) travel or lift to the feed roller can be eliminated by the use of adjustable stroke cylinders, such as which can be accomplished in a manual type operation.
For these reasons, accurate controlling of the pilot function for lift rate/speed/travel is difficult to control and is typically results in the utilization of a pre-set motion/rate in the assembly, such further resulting in considerable inefficiencies of operation. It is also found that the return motion of the feed roll cannot be controlled via a given rate or speed and results in imparting undesirable effects onto the uncoiled feed material and as the feed roll contacts the material with uncontrolled force (such as further which take into account the full weight of the feed roll and the upper piloting assembly, or via a slide block assembly).
The net effect of these operational limitations is that they can cause undesirable marking of the uncoiled and fed material, this most notably found in sensitive surface finish materials. As such, combined factors including rate of return, pressure in the cylinder and resultant lift-off or travel cannot be controlled using current technologies and methods, this further evidenced by the position of the feed roll during the lift cycle with the air cylinder not being accurate and further limited by hard stops inside the cylinder or an adjustable threaded rod acting as a hard stop.
The present invention discloses a feed assembly for transferring an uncoiled sheet material to a downstream material forming operation. The assembly includes upper and lower feed rolls between which the sheet material passes, the upper roll being actuated between engaging or disengaging positions relative to an upper surface of the sheet material. At least one continuous force applying component is provided for exerting a hold down force against the upper feed roll and, in combination, a programmable counterbalance component is calibrated to counter the hold down force exerted by the force applying component and in order to cycle the upper roller between the engaged and disengaged positions during advance cycling of the uncoiled material to the downstream forming operation.
Additional features include a cam shaft with end support cam lobe provided in supported and extending fashion between a pair of side supporting plates. A servo cam and gearbox operates the cam lift components for providing highly tuned and responsive movement of the upper feed roller relative to the lower feed roller.
The servo cam lift operates in conjunction with a pair of the continuous force hold-down components and with the programmable counterbalancing sub-assembly supported between a mounting rail and counter balance mounting beam in order to counter a PSI applied force of the hold down components (also termed air bladders). In this manner, the assembly accomplishes incremental grip and release motion of the upper feed roller in a highly timed and repetitive fashion for effectuating rapid and effective transfer of the uncoiled material to the downstream press operation.
In one non-limiting application, the servo cam can cycle at a range of 0.020 seconds or faster and at a cycling rate of 80-300 iterations per minute or more, at a range further of between 0.000″ home position and 0.400″ lift position. Other and additional features include pivot linkages respectively associated with first and second brackets, between which the programmable counterbalance component is supported and which, upon being actuated, exerts a lifting force to the mounting rail which is in turn likewise connected to the force applying or air bladder components.
Reference will now be made to the attached drawings, when read in combination with the following detailed description, wherein like reference numerals refer to like parts throughout the several views, and in which:
As will be further described with subsequent reference to
Relevant components of the press feed mechanism described herein include a drive or cam shaft 12 with end support cam lobe 14 (see also enlarged views of
To that end, the description of the gearing and structure associated with the servo motors and associated gearing to rotating shaft 12 connections is only generally shown and understood to operate with the use of conventionally known gears and related structure as generally illustrated in
As will be further described in additional detail, the servo cam lift operates in conjunction with a pair of continuous force hold-down components 28 and 30 (commonly termed air bladders) and a programmable counterbalancing sub-assembly 32 (which is supported between mounting rail 34 and counter balance mounting beam 36) counters the PSI applied force of the air bladders 28 and 30 for accomplishing incremental grip and release motion of the upper feed roller 24 relative to the lower fixed position and rotating roller 26 in a highly timed and repetitive fashion for effectuating rapid and effective transfer of the uncoiled material to the downstream press operation.
With the above essential structural description, the servo cam operates in combination with one or more (typically a pair of) continuous hold down force assemblies 28 and 30 (depicted as air bladders however potentially including any other type of mechanical, electro-mechanical, hydraulic or other fluidic force applying construction which may be known in the art) which can be arranged proximate opposite and lateral extending ends of the rollers. Also provided is the further programmable counter balancing component (previously described at 32) which operates with the air bladders and servo cam lift for providing highly responsive and fine-tuned lifting of the upper displaceable feed roller 24 relative to the fixed rotating lower roller 26 (via rotation of the eccentric or cam shaped lobe 14 associated with shaft 12 which translates displacement forces to the end supported roller 48) and in order to facilitate transfer of the uncoiled sheet material from the feed assembly to the material press, stamping operation or the like located downstream from the feeding mechanism.
By this construction, lifting motion of the upper feed roller can be controlled to increments as low as 0.001″ with a corresponding rate of lift and return response time of 20 ms (milliseconds) or less. As will also be described, and according to one non-limiting preferred embodiment, the present system is equipped with either any of a single, dual or other multiple of force hold down components (e.g. air bladders) which operate to maintain a constant down pressure on the upper roll (programmable) and which allows for material thickness variations as the uncoiled (steel) material is passing between the upper and lower feed rolls.
The air bladder components further act as cushions in response to sensing variations in the thickness of the uncoiled steel (such commonly being known to account for 5-10% variation in mill steel thickness). Additional features again include the provision of a programmable counterbalance assembly, such exerting a reverse (unseating/lifting) force to the upper feed roll in order to counter the continuous force applying hold down components (air bladders) and which further assists the servo cam lift in overcoming the continuous downward applied forces of the air bladders.
In one non-limiting application, the programmable counterbalancing component can be set to a variable minimum for overcoming the mechanical weight of the assembly (feed roller and associated components) and the existing PSI holding force applied through the air bladders/force hold down components. One known range of settings can include a 0-100 PSI down pressure applied to the upper feed roll (assuming a 2″=4″ bore upper air cylinder at 80 PSI=3,400 lbs of down force, and an upper roll assembly weight of approximately 1,000 lbs). A non-limiting variant of the present design allows for up to 8,000 lbs of programmable counterforce.
In operation, the servo cam lift can be set to a minimum desirable lift dimension above the material thickness of the uncoiled steel. By example, and in the instance of the assembly running a 0.100″ thick stock, a lift variable can be programmed for 0.0101″, with a further minimally desirable proper operational protocol suggesting a lift dimension of 0.008″-0.010″.
During setup, an operator can program into the PC readable component a material thickness which in turn operates the positioning of the cam (with resultant lift-off of the upper feed roller). One non-limiting setting would have the cam retract to allow the upper roll to ride on the uncoiled sheet material surface, free from obstruction from the cam. Then, when actuated, the cam would rotate/lift to achieve the desired (programmed) lifting of the upper feed roller above the material thickness of the uncoiled steel, thereby allowing the material to “float” for the pilot function. Upon subsequently receiving a signal to close, the cam would then reverse rotate (retract) back to the current home position to allow the sheet material to be gripped and thereby advanced and allowing the force holding components (air bladders) to apply their rated PSI pressure in full.
Referring back to the illustrations,
The force hold down components 76/78 are further depicted anchored to undersides of the brackets 80/82 in downwardly extending (as opposed to angled fashion as in
See also as further shown bracket supports 88 and 90 which are also depicted in
Additional key components of the servo pilot mechanism include the servo motor being sized in any desired range (such as 70-600 in-lb), with the corresponding gearbox assembly exhibiting a calculated ratio ranging from 1:1 to 25:1. The gearbox utilized can further exhibit zero or low backlash properties and can further include any of an in-line or right angle type construction.
The camshaft assembly utilized can further be mounted within a housing via taper roll bearings with locknuts and washers. Alternately, other economical assemblies are envisioned which can include any type of bushing arrangement.
The programmable (air) counterbalancing component 32 can also envision utilizing any other type of mechanical (including electro-mechanical servo variant), pneumatic or hydraulic redesign (or can provide a combination of all) such as in order to eliminate the upper roll 24 and assembly weight and to assist in overcoming the PSI down force exerted by the hold down (air bladder 28/30) components. To this end, additional redesigns of the invention contemplate single or dual air bladders utilized for providing feed roll pressure, such further with or without mechanical spring counterbalances.
It is also generally accepted that a servo pilot release provides improvements over standard air release options which define the industry standard. It is further understood that the “process” or “operation” of the pilot release cycle function during the stamping process/cycle of the press can have substantial impact on the accuracy of the feed mechanism, such as in which the rapid tuning of the upper roller 24 in effect causing the feeder to “release” the steel to float.
Additional factors include adjustment to the pilot timing in order to effect part length, mostly due to the “Lag” time associated with Air release. In this fashion, the timing of the servo release greatly improves this accuracy by minimizing the lift above the steel and the rate of return in which the feed rolls (24 and 26) close or contact.
By virtue of such an arrangement, factors eliminated in a traditional setup of the feed mechanism include energizing the solenoid valve, the time for air to travel to lift cylinders, the time needed to fill the cylinder with air and in order to achieve the proper pressure, the cylinder lift time and, finally, the cylinder lift travel. In reverse operation, time delays include for each of the spool being closed on the solenoid valve, forcing the air from the cylinder “dump air”, the time for the cylinder to travel from full open back to closed position, and finally for the roller 24 to meet or contact the sheet material (concerns here are force of impact and possible material marking).
The high speed servo mechanism incorporated into the present invention largely eliminates the time it takes for the above pre-existing process, and by the rapid movement of the servo cam lift. The present mechanism also helps reduce “long feeds” and “short feeds” associated with the pilot release portion of the press cycle when using an air system, mostly due to timing lag.
A programmable setting allows for a down force applied to the upper feed roll 24, and which again is calibrated in order to absorb variances in material thickness as the uncoiled steel passes through the feed machine to the downstream press or other stamping operation. Other variants include provision of a shaft mount style cam follower. An eccentric shaft can also be incorporated, and which may have less than a 0.006″ (torsional) twist with 36,000 inLbs applied.
Yet additional operational considerations include the cycling/response time (such as between the positions of
As also previously described, the air bladder pressure may be programmable within the parameters (job recipe) programmed into the PC component of the assembly, the air counterbalancing pressure (component 32) is also a programmable aspect and can include a minimal pressure setting for countering or eliminating the combined weight of the upper pivot assembly and roller weight (such as approximately 900 lb for a 48 machine with 6″ rolls). Other considerations may include incorporating a maintenance program that fully cycles the servo and gearbox to help reduce in wear (factoring that the servo will only be moving back and forth most of the time in small increments). A manual mode may also be utilized to cycle programmed lift during setup.
The associated service screen utilized with the PC component of the servo cam is desirously accessed by authorized personnel only, such as via password input. This functionality can further include each of calibrating to zero, adjusting acceleration/deceleration of the cam lift profile, adjusting velocity, etc. This can further envision different profiles being programmed which, for example, applies to sensitive or pre-painted uncoiled materials in which softer closing or gripping of the upper roller is desired in order to prevent material wear or damage during cycling.
By its construction, the combination of the continuous hold down force applying components 28/30 and the opposing or counter force exerting component 32 operate in order to finely tune or adjust both the force of contact exerted between the rollers 24 and 26, as well as the creation of a minute separate distance therebetween. This combination further permits the inter-communicated sheet of steel material to be precisely advanced and, when initiating the subsequent press operation, to securely and effectively grip the steel sheet in order to prevent bending/creasing to the same or misalignment at the entry location to the adjoining press. In this fashion, the present invention provides for both faster and more accurate feeding of the uncoiled steel sheet in the succeeding press or other stamping/forming operation than has been heretofore possible.
Having described my invention, other and additional preferred embodiments will become apparent to those skilled in the art to which it pertains, and without deviating from the scope of the appended claims.
This Application claims the benefit of U.S. Provisional Application 62/119,289 filed on Feb. 23, 2015, the contents of which are incorporated herein in its entirety.
Number | Date | Country | |
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62119289 | Feb 2015 | US |