Abstract:
An improved slide lock mechanism for a vacuum valve ( 10 ) including an end plate or bonnet ( 42 ) mounted to an end flange ( 46 ) and a pair of slide lock plates ( 14 ). An elongated drive shaft pinion ( 36 ) drives a rack ( 52 )connected to slide lock plates ( 14 ), to linearly shift the slide lock plates into clamping engagement with guide screws ( 20 ), thus achieving a tight seal at upper flange ( 46 ) and bonnet ( 42 ). Elongated drive shaft pinion ( 36 ) provides access from above vacuum valve for disengaging, or unclamping, the valve plate and its actuator for repair or maintenance.

Description:
RELATED APPLICATION 
     This application claims priority on U.S. Provisional Application 60/143,141, filed Jul. 7, 1999. 
    
    
     FIELD OF THE INVENTION 
     The present invention pertains to vacuum valves for applied processing systems and, more particularly, to an improved quick release clamp mechanism for connecting and disconnecting the bonnet and flange of gate valves. 
     BACKGROUND OF THE INVENTION 
     My U.S. Pat. No. 5,791,632, entitled “Quick Release Slide Lock for Vacuum Valve,” discloses a quick release clamp mechanism for releasing or disengaging the bonnet of the gate valve actuator from the valve body flange associated therewith. The disclosure of this reference is incorporated herein. While the quick release mechanism disclosed in this patent provides an efficient quick release and a tight seal for operation, the drive of the computer chip manufacturing industry to smaller and smaller processing systems makes servicing and performing routine maintenance of such systems more difficult. The present invention addresses these difficulties with an improved quick release mechanism that better takes advantage of limited, yet available, space. 
     DISCLOSURE OF INVENTION 
     Briefly described, the improved vacuum valve of the present invention comprises a clamp actuator that extends through the end plate of a valve housing that defines a valve chamber and includes a main opening. The clamp actuator extends from above the end plate and is connected to a clamp mechanism of the valve for moving the clamp mechanism between its first position and its second position. A valve plate is provided that is movable within the valve chamber from a first, open position away from the main opening to a second, closed position wherein the valve plate closes the main opening to prevent vacuum media flow, and a valve plate actuator moves the valve plate between its open and closed positions. The valve plate actuator and valve plate are secured to the end plate so that removal of the end plate in an upward direction separates the valve plate actuator and valve plate from the actuator end of the valve housing. The valve housing also includes an end plate engaging member. Further, the clamp mechanism is coupled to one of the end plate and end plate engaging member, with the clamp mechanism having a first position allowing separation of the end plate from the end plate engaging member and a second position that securely holds the end plate to the end plate engaging member in a sealed manner. 
     In this manner, access is provided from the actuator end of the vacuum valve, or at least from the outer side of the valve actuator, which allows for more compact design of the vacuum valve, while at the same time providing easy access for repair and maintenance purposes. 
     According to an aspect of the invention, the clamp actuator includes a pinion component and the clamp mechanism includes a rack component coupled to the pinion component, whereby rotation of the pinion component causes linear movement of the rack component, causing the clamp mechanism to move between its first and second positions. Preferably, the clamp actuator includes an elongated drive shaft connected to the pinion component, the elongated drive shaft extending away from the end plate beyond an outer end of the valve plate actuator, to provide access from above the end plate for service. 
     According to another aspect of the invention, the drive shaft includes an outer end that has a drive coupling for manual rotation of the drive shaft and connected pinion component, in order to shift the clamp mechanism. 
     These and other features, advantages and objects of the invention will become apparent from the following description of the best mode for carrying out the invention, when read in conjunction with the accompanying drawings, and the claims, which are all incorporated herein as part of the disclosure of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings, like reference numerals refer to like parts throughout the several views, wherein 
     FIG. 1A is a longitudinal sectional view of the actuator assembly of the upper region of the valve body, showing the bonnet and flange connection and the improved quick release mechanism for separating the two; 
     FIG. 1B is a side elevation view of the actuator housing of FIG. 1A, with the valve housing shown in section; 
     FIG. 1C is a longitudinal section view of the actuator housing 
     FIG. 2 is cross-section view of the components of FIG. 1A; and 
     FIG. 3 is a horizontal section view of the clamp plates and quick release clamp mechanism. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference will now be made in detail to the preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. While the invention will be described in conjunction with the preferred embodiments, it will be understood that the described embodiments are not intended to limit the invention specifically to those embodiments. On the contrary, the invention is intended to cover alternatives, modifications and equivalents, which may be included within the spirit and scope of the invention. 
     Referring to FIG. 1A, the improved gate valve  10  of the present invention includes a gate valve mechanism (not shown) that is substantially the same as that disclosed in my U.S. Pat. No. 5,884,899, entitled “Half Profile Gate Valve.” Gate valve  10  is provided with a slide lock mechanism  12  that is similar to that disclosed in my U.S. Pat. No. 5,791,632 entitled “Quick Release Slide Lock for Vacuum Valve” in that it includes a pair of slide lock plates  14  (only one shown) one on each side of the gate valve. Slide lock plates  14  are movable in the direction of arrows  16  and function to lock and release an actuator assembly  30  with respect to valve housing  50 . 
     Slide lock plates  14  each include a set of four longitudinally spaced slots  18  that receive downwardly extending guide screws  20  from the housing of actuator assembly  30  that function as discussed in my &#39;632 patent. Slide lock plates  14  also include a pair of slots  22  that each receive a shoulder screw  24 , and this design is also disclosed in my &#39;632 patent. 
     FIGS. 1B and 1C show the design of openings  18  in one of the slide lock plates  14 . Each opening  18  is generally oblong circular in shape and includes a wide diameter half  19  and a neck down small diameter half  21 . The wide diameter half  19  is wide enough to pass the head of a guide screw  20  therethrough, while the neck down region is not. In FIG. 1C, the line delineating the wide and small diameter regions is denoted by reference  23 . 
     Opening  18  also includes a beveled region  25 , which consists of a bevel cut that has a progressively diminishing depth so as to form a ramp or cam surface  27 . During clamping, the head of a guide screw engages cam surface  27  and is pulled thereby as a slide lock plate is slid longitudinally, in order to clamp the bonnet plate down onto the valve body flange. The slope of cam surface  27 , depicted by arrows  29 , is approximately 5 degrees, which creates sufficient difference in depth of bevel region  25  to clamp the bonnet plate onto the valve body flange. When the gate valve is operational, the vacuum pressure within the valve housing augments the clamping force of the slide lock plates, which together create an adequate seal at the bonnet plate. 
     The design of actuator assembly  30  is similar to that disclosed in my &#39;899 patent. The upper end of gate valve  10  has been modified to include an enclosure formed by a top plate  32 , an end wall  34 , and side walls (not shown). Top plate  32  provides a mount for a release drive shaft pinion  36 , the upper end of which extends above top plate  32  and outwardly beyond actuator  30  and includes a drive coupling in the form of a hex socket  38  for receiving a wrench for manual turning of shaft  36 . 
     An upright tubular collar support  40  is secured to the bonnet  42  of gate valve  10  and includes an inner bushing sleeve  44 . Drive shaft pinion  36  extends down through aligned openings in bonnet  42  and the upper flange  46  of valve housing  50  and into a machined recess slot  48  of slide lock plate  14 . The design and operation of shaft  36  and recess  48  are discussed with reference to FIGS. 2 and 3. 
     Referring to FIG. 1B, with slide lock plate  14  moved to the right, as shown by arrow  16  (along with movement of the other slide lock plate), actuator assembly  30  is able to be lifted from the valve housing  50 , and this is also discussed in my &#39;632 patent. 
     The bottom end of release shaft  36  is splined to interengage with the teeth of a rack  52  mounted to plate  14  within recess  48 . The splines of shaft  36  are freely released from the teeth of rack  52  upon lifting of actuator assembly  30 , as are guide screws  20  from slots  1 B. 
     FIG. 2 shows both release shafts  36  and slide lock plates  14  with the pinion ends of shafts  36  engaging racks  52 . Rotation of both release shafts by a maintenance technician causes sliding movement of both slide lock plates, freeing their guide screw heads from the slots of the slide lock plates. 
     FIG. 3 is a top view of the slide lock plates  14  and the release mechanism of shafts  36  and racks  52 . Each release shaft  36  extends down into its respective recess  48  on the inside of a rack  52 , which are secured at the outer sides of recesses  48 . Rotation of release shafts  36  causes linear movement of slide lock plates  14  in the direction of arrows  16 , which either release guide screws  20  from or engages guide screws  20  with their respective slots  18 , to release or lock the actuator assembly. 
     Provision of a quick release mechanism accessible from above the gate valve has the advantage of allowing easy access to the gate valve for maintenance purposes. Typically, gate valves are sandwiched between modules of applied processing systems and for this reason have to be fully removed for maintenance and repair. The present invention for removal of only the actuator, leaving the valve mechanism and/or housing in place. 
     The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the Claims appended hereto when read and interpreted according to accepted legal principles such as the doctrine of equivalents and reversal of parts.