SYSTEMS AND METHODS FOR PROVIDING RAPID AND SAFE OPENING OF PRESSURE NIP ROLLS
An actuator system for maintaining high nip forces at a roller nip is disclosed. The actuator system includes a primary actuator for urging a roller into an engaged position at which the roller contributes to providing the high nip forces at the roller nip, the primary actuator being provided attached to a movable mounting structure, and a secondary actuator for maintaining the mounting structure in a locked position, and for releasing the mounting structure, and therefore the primary actuator, from the locked position in the event of a power loss to the secondary actuator.
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The present application claims priority to U.S. Provisional Patent Application Ser. No. 62/502,954 filed May 8, 2017, the disclosure of which is hereby incorporated by reference in its entirety.
FIELD OF THE INVENTIONThe present invention generally relates to the field of controls systems for pressure nip rolls, and relates in particular to safety systems for use in such control systems.
BACKGROUNDMechanical actuators are commonly used in applications where high nip forces are needed in the production, for example, of polymer film and sheet. These actuators generally require either electric or hydraulic power to exercise position and gap control of one or more of the nip rollers. In the event of an emergency (such as loss of power), safety to personnel is a significant concern. If power is lost, the nip rollers may bind, lock up or respond in an unpredictable way.
Further, any material that is moving through the nip may continue moving in an uncontrolled fashion, endangering personnel. It is also possible that the nip rollers themselves and other equipment may become damaged from such an emergency, let alone the material being processed by the pressure nip rollers.
The remains a need therefore, for an improved safety system for pressure nip rollers.
SUMMARYIn accordance with an embodiment, the invention provides an actuator system for maintaining high nip forces at a roller nip. The actuator system includes a primary actuator for urging a roller into an engaged position at which the roller contributes to providing the high nip forces at the roller nip, the primary actuator being provided attached to a movable mounting structure, and a secondary actuator for maintaining the mounting structure in a locked position, and for releasing the mounting structure, and therefore the primary actuator, from the locked position in the event of a power loss to the secondary actuator.
In accordance with another embodiment, the invention provides an actuator system for maintaining high nip forces at a roller nip. The actuator system includes a primary actuator system for urging a roller into an engaged position at which the roller contributes to providing the high nip forces at the roller nip, the primary actuator system including at least one primary actuator that is provided attached to a base, and a secondary actuator system for maintaining the base in a locked position, and for releasing the mounting structure, and therefore the primary actuator system, from the locked position in the event of a power loss to the secondary actuator system.
In accordance with a further embodiment, the invention provides a method of maintaining high nip forces at a roller nip. The method comprising the steps of urging a roller into an engaged position at which the roller contributes to providing the high nip forces at the roller nip, and releasing a mounting structure to thereby release the roller from the roller nip in the event of a power loss to the secondary actuator.
The following description may be further understood with reference to the accompanying drawings in which:
The drawings are shown for illustrative purposes only.
DETAILED DESCRIPTIONIn accordance with an embodiment, the invention provides an actuator system for maintaining high nip forces at a roller nip. The actuator system includes a primary actuator and a secondary actuator. The primary actuator is for urging a roller into an engaged position at which the roller contributes to providing the high nip forces at the roller nip. The primary actuator is provided attached to a movable mounting structure. The secondary actuator is for maintaining the mounting structure in a locked position, and for releasing the mounting structure, and therefore the primary actuator, from the locked position in the event of a power loss to the secondary actuator. In certain embodiments, the mounting structure includes a primary actuator base, the primary actuator includes a high force mechanical actuator and the secondary actuator includes a pneumatic cylinder.
The primary actuator 12 may be an actuator that is not affected by a loss of power, and may be mounted on the mounting structure 20, such as a primary actuator base. The primary actuator base 20 may be slidable on the system base 22, and may be held in a locked position by a secondary actuator 24, including the pneumatic cylinder 26 and the linkage system 28. The rollers 14, 16 may be any arbitrary length, and the system 10 may include the above components at each of the two ends of the roller 14, for urging the roller 14 into contact with the roller 16 by pushing the ends of the roller 14 toward the roller 16. In various embodiments, bases 18 and 22 may be separate bases or may be combined as a single based (as shown in
In accordance with another embodiment, a system 50 may include a pair of primary actuators 52, such as high force mechanical actuators (e.g., jack screws 53), for urging a roller 54 toward another roller 56 to form a roller nip under high pressure. The primary actuator 12 may include a mounting structure 60 on a unitary system base 58, and may be engaged to urge the roller 54 toward the roller 56 by way of the pair of mechanical actuators 53.
The system includes a linkage system similar to the above embodiment, and while the secondary actuator system 64 is activated in the locked position, a pneumatic cylinder 66, via a linkage system, locks the base 52 of the primary actuator system such that the roller 54 is urged against the roller 56. When power to the pneumatic cylinder 66 is shut off (e.g., in an emergency power outage), the piston of the pneumatic cylinder 66 retracts, causing the linkage system to relax and draw the base 52 of the primary actuator system away from the roller 56 as discussed above.
The system therefore provides an actuator system for maintaining high nip forces at a roller nip, and includes a primary actuator system and a secondary actuator system. The actuator system includes the primary actuator system for urging a roller into an engaged position at which the roller contributes to providing the high nip forces at the roller nip. The primary actuator system includes at least one primary actuator that is provided attached to a base. The secondary actuator system is for maintaining the base in a locked position, and for releasing the mounting structure, and therefore the primary actuator system, from the locked position in the event of a power loss to the secondary actuator system.
Those skilled in the art will appreciate that numerous modifications and variations may be made to the above disclosed embodiments without departing from the spirit and scope of the present invention.
Claims
1. An actuator system for maintaining high nip forces at, a roller nip, said actuator system comprising:
- a primary actuator for urging a roller into an engaged position at which the roller contributes to providing the high nip forces at the roller nip, said primary actuator being provided attached to a movable mounting structure; and
- a secondary actuator for maintaining the mounting structure in a locked position, and for releasing the mounting structure, and therefore the primary actuator, from the locked position in the event of a power loss to the secondary actuator.
2. The actuator system as claimed in claim 1, wherein the movable mounting structure provides a base for the primary actuator, and wherein the secondary actuator is coupled to the base of the primary actuator.
3. The actuator system as claimed in claim 1, wherein the primary actuator includes a high force mechanical actuator.
4. The actuator system as claimed in claim 1, wherein the secondary actuator includes a pneumatic cylinder.
5. The actuator system as claimed in claim 1, wherein the secondary actuator includes a linkage system that locks when the secondary actuator is in the locked position.
6. The actuator system as claimed in claim 1, wherein the actuator system includes at least one further primary actuator, attached to the movable mounting structure, for urging the roller into the engaged.
7. The actuator system as claimed in claim 1, wherein the actuator system includes at least one further secondary actuator for maintaining the mounting structure in the locked position, and for releasing the mounting structure, and therefore the primary actuator, from the locked position in the event of power loss to the secondary actuator.
8. An actuator system for maintaining high nip forces at a roller nip, said actuator system comprising:
- a primary actuator system for urging a roller into an engaged position at which the roller contributes to providing the high nip forces at the roller nip, said primary actuator system including at least one primary actuator that is provided attached to a base; and
- a secondary actuator system for maintaining the base in a locked position, and for releasing the mounting structure, and therefore the primary actuator system, from the locked position in the event of a power loss to the secondary actuator system.
9. The actuator system as claimed in claim 8, wherein the primary actuator system includes at least two high force mechanical actuators.
10. The actuator system as claimed in claim 8, wherein the secondary actuator system includes at least two pneumatic cylinders.
11. The actuator system as claimed in claim 8, wherein the secondary actuator system includes at least two linkage systems that lock when the secondary actuator system is in the locked position.
12. The actuator system as claimed in claim 8, wherein the primary actuator system includes two primary actuators.
13. The actuator system as claimed in claim 8, wherein the secondary actuator system includes two secondary actuators.
14. A method of maintaining high nip forces, at a roller nip, said method comprising the steps of:
- urging a roller into an engaged position at which the roller contributes to providing the high nip forces at the roller nip; and
- releasing a mounting structure to thereby release the roller from the roller nip in the event of a power loss to the secondary actuator.
15. The method as claimed in claim 14, wherein the method further includes, the step of locking the mounting structure in a locked position.
16. The method as claimed in claim 14, wherein the step of releasing the mounting structure is responsive to power loss to one or more pneumatic cylinders.
Type: Application
Filed: May 8, 2018
Publication Date: Dec 6, 2018
Applicant: PARKINSON TECHNOLOGIES INC. (Woonsocket, RI)
Inventors: John Whaley (North Kingstown, RI), James Munoz (Cumberland, RI)
Application Number: 15/974,027