1. Field
Embodiments of the present invention relate to clamps for securing rolling mill roll stands to support structures.
2. Description of Related Art
Roll stand clamps typically have clamping jaws operated by the pistons of double acting hydraulic cylinders. The clamps operate in hostile environments in which they are constantly exposed to cooling water containing abrasive mill scale and other entrained contaminants. Over time, ingress of these elements gradually prevents the piston rods from sliding smoothly in the cylinders, to the point where the clamps no longer function. Clamp malfunctions can complicate removal and replacement of roll stands, thus prolonging mill down time. Also, in the event of a loss of hydraulic pressure, the clamps lose their ability to reliably secure the roll stands in place along the mill pass line.
Broadly stated, embodiments of the present invention address the problems described above by providing an improved roll stamp clamp having enhanced external guards and internal seals designed to effectively prevent ingress of contaminants.
In exemplary embodiments of the present invention, the clamp is designed as a cartridge that can readily be inserted into and removed from the stand support structure.
In a preferred exemplary embodiment of the present invention, the clamp comprises a tubular housing having a cylindrical interior extending along a central axis from a closed rear end to an open front end. A piston subdivides the housing interior into front and rear chambers. A clamping jaw projects forwardly from the piston through the open front end of the housing. A resilient means acts in the rear chamber to exert a locking force urging the piston and the clamping jaw into a locked position. In order to unlock the clamp, a hydraulic fluid means acts in the front chamber to overcome the resilient locking force of the resilient means.
As herein employed, “resilient means” means enclosed or self contained mechanisms capable of exerting closure or locking forces without the aid of externally generated power sources.
In exemplary embodiments of the present invention, the rear chamber of the clamp is filled with a liquid lubricant.
The resilient means may comprise at least one spring, and preferably a plurality of stacked Belleville springs, axially confined between the closed rear end of the housing and the piston. Gas charged openings may also serve as resilient means.
In other exemplary embodiments of the present invention, an expandable bellows and/or cylindrical shroud serve to prevent ingress of cooling water and entrained contaminants.
These and other objects, features and advantages of the present invention will become more apparent upon reading the following detailed description in conjunction with the accompanying drawings.
The components described hereinafter making up the various embodiments are intended to be illustrative and not restrictive. Many suitable components that would perform the same or a similar function as well as the materials described herein are intended to be embraced within the scope of embodiments of the present invention.
Referring now to the figures, wherein like reference numerals represent like parts throughout the views, embodiments of the present invention will be described in detail.
With reference initially to
The posts 14 project upwardly from a base 18 secured to a support structure 20 by a clamp 22 in accordance with an exemplary embodiment of the present invention.
With reference additionally to
As depicted in
A piston 34 subdivides the interior of the housing 24 into front and rear chambers 34, 38.
A clamping jaw 40 projects forwardly from the piston 34 through the annular insert 31 at the open end of the housing 24. The piston 34 is reciprocally movable along axis A between a locked position engaging a component 42 of the roll stand base, as shown in
Preferably, and again as shown in
A resilient means acts in the rear chamber 38 to exert a locking force urging the piston 34 and the clamping jaw 40 forwardly into the locked position. The resilient means comprises at least one spring, and preferably comprises a plurality of Bellville springs 44 confined between the end plate 26 and the piston 34 in a stacked arrangement along axis A.
In order to unlock the clamp 22, a fluid means acts in the front chamber 36 to overcome the resilient locking force of the resilient means in the rear chamber 38. As can best be seen in
In order to exclude cooling water and entrained contaminants from penetrating into the interior of the housing 24, an expendable bellows 48 is connected at opposite ends to the housing and the clamping jaw 40.
Additionally, a cylindrical shroud 50 projects forwardly from the housing 24 to surround the bellows 48.
Preferably, a first O-ring seal 52 is positioned on the piston for sealing engagement with the interior surface of the housing 24. A second O-ring seal 54 may be positioned within the annular insert 31 for sealing engagement with a cylindrical section of the clamping jaw 40.
A piston rod 56 extends rearwardly from the piston 34. The piston rod is slidebly received in an annular guide 58 supported by the end plate 26. A guide pin 60 projects internally from the end plate 26 and is slidebly received in a blind bore 62 in the rear end of the piston rod 56.
Preferably, the rear chamber 38 is filled with a liquid lubricant received via a port 64 in the end plate 26 from an external storage tank 66. The liquid filled rear chamber further serves to exclude contaminants from the interior of the housing 24.
In light of the foregoing, it will now be understood that the clamp 22 of the present invention operates in a “fail safe” mode because of its enclosed or self contained resilient means, which will reliable exert a clamping force regardless of any type of power loss or failure of ancillary equipment.
While exemplary embodiments of the invention have been disclosed, modification, additions and deletions can be made without departing from the spirit and scope of the invention and its equivalents, as set forth in the following claims.