Patent Publication Number: US-2015082584-A1

Title: Clamp for rolling mill roll stand

Description:
BACKGROUND 
     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. 
     SUMMARY 
     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. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an elevational view of a rolling mill roll stand secured to an underlying support structure by a clamp in accordance with an exemplary embodiment of the present invention; 
         FIG. 2  is an enlarged front view of the clamp shown in  FIG. 1 ; 
         FIG. 3  is a perspective view of a clamp in accordance with an exemplary embodiment of the present invention; 
         FIGS. 4 and 5  are sectional views taken respectively along lines  4 - 4  and  5 - 5  of  FIG. 2 , and showing a clamp in accordance with an exemplary embodiment of the present invention in a locked position; 
         FIG. 6  is a view similar to  FIG. 5  showing the clamp in an unlocked position; and 
         FIG. 7  is a perspective view showing a clamp in accordance with an exemplary embodiment of the present invention withdrawn from roll stand support structure. 
     
    
    
     DETAILED DESCRIPTION 
     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  FIG. 1 . a rolling mill roll stand  10  has a pair of work rolls  12  supported between housing posts  14  interconnected by bridging elements  16 . 
     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  FIGS. 2-6 , it will be seen that the clamp  22  comprises a tubular housing  24  having a cylindrical interior extending along a central axis “A”. A rear end of the housing  24  is closed by an end plate  26  secured to the housing by bolts  28  or the like. A front end of the housing is open and defined by a circular collar  30  lined with an annular insert  31 . 
     As depicted in  FIG. 7 , the cylindrical housing is in effect a cartridge designed for inserting into and removal from a cylindrical opening  32  in the support structure  20 . 
     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  FIGS. 4 and 5 , and an unlocked position at which the clamping jaw is removed from the component  42 , as shown in  FIG. 6 . 
     Preferably, and again as shown in  FIG. 6 , the clamping jaw  40  has a beveled clamping surface  40 ′ configured and dimensioned to coact with a correspondingly beveled surface  42 ′ on the roll stand component  42 . 
     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  FIG. 5 , the fluid means may comprise pressurized hydraulic fluid introduced into the front chamber  36  via a passageway  46  in the wall of the housing  24 . 
     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.