Gate valve

Abstract

To provide a gate valve which can suppress an increase of weight and a cost.SOLUTION: A gate valve 10 is arranged between first and second chambers, makes a first opening part communicating with the first chamber and a second opening part communicating with the second chamber communicate with each other, and individually opens and closes the opening parts. The gate valve has: a valve shaft 17; first and second valve plates 21, 22 attached to a tip part of the valve shaft; an operation mechanism 24 for moving the valve plates to a retreat position for making the first and the second opening parts communicate with each other, a first block position for blocking the first opening part by the first valve plate, and a second block position for blocking the second opening part by the second valve plate; a fastening mechanism 30 for fastening the valve plates and the valve shaft to each other so as to be engaged and disengaged in a state that the tip part of the valve shaft is sandwiched between the valve plates, and attaching the valve plates to the tip part of the valve shaft so as to be attachable and detachable; and a support mechanism 50 for fastening the valve plates so as to be engaged and disengaged at least at both end parts of the valve plates in a longitudinal direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a gate valve to be placed between chambers in a semiconductor manufacturing apparatus or the like, and more specifically to a gate valve to be placed between a first chamber such as a transfer chamber and a second chamber such as a process chamber that are adjacent to each other, for connecting a first opening leading to the first chamber and a second opening leading to the second chamber to each other or for individually opening and closing the first and second openings. [Background technology]

[0002] In such gate valves, a pair of valve plates are arranged back to back, and each of the openings can be opened and closed individually by abutting a seal member attached to the valve plates against a seat surface formed around each opening. However, the valve plates require periodic maintenance, such as replacing a deteriorated seal member when it deteriorates, because the seal member gradually deteriorates with use. However, conventionally, performing maintenance on the valve plates, such as replacing a seal member, required the entire gate valve to be temporarily removed from between the chambers, which required a lot of time and effort.

[0003] Therefore, in the gate valve described in Patent Document 1, a support plate is attached to the tip of the valve shaft. end The valve shaft is detachably attached to the support plate from the valve shaft side, and a pair of valve plates are detachably attached to both sides of the support plate from the tip side of the valve shaft. Therefore, as described in Patent Document 1, for example, by removing the top wall that closes the tip side of the valve body that houses the valve plates, it becomes possible to access the valve plates and support plates from the tip side, making it possible to easily perform maintenance work on the valve plates without removing the entire gate valve from between the chambers. On the other hand, considering the costs of manufacturing and operating, it is desirable to keep the weight of the valve plates and their surroundings as small as possible. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-94795 Summary of the Invention [Problem to be solved by the invention]

[0005] Therefore, the technical object of the present invention is to provide a gate valve that not only has excellent workability during valve plate maintenance, but also allows for reduction in various costs by reducing the weight around the valve plate. [Means for solving the problem]

[0006] In order to solve the problems, a gate valve according to the present invention is a gate valve that is disposed between a first chamber and a second chamber adjacent to each other, and that interconnects and individually opens and closes a first opening that communicates with the first chamber and a second opening that communicates with the second chamber, and that includes a valve shaft that extends in an axial direction from a base end side to a tip end side, a first valve plate and a second valve plate that are attached to the axial tip end of the valve shaft and are formed long in a direction perpendicular to the axis, and that have an inner surface that faces the valve shaft side and an outer surface that is fitted with an annular seal member and faces away from the inner surface, and that operates the valve shaft to open and close the first and second valve plates, which interconnect the first opening and the second opening. and an operating mechanism for moving the first and second valve plates to a first evacuation position, a first closing position in which the first opening is closed by the outer surface of the first valve plate, and a second closing position in which the second opening is closed by the outer surface of the second valve plate; and the gate valve further comprises a fastening mechanism that detachably attaches the first and second valve plates to the tip portion of the valve shaft by detachably fastening the first and second valve plates and the valve shaft to each other with the inner surfaces of the first valve plate and the second valve plate abutting against the tip portion of the valve shaft and sandwiching the tip portion of the valve shaft between the valve plates, and at least one set of support mechanisms that detachably fasten the first and second valve plates to each other at least at both longitudinal ends of the first and second valve plates.

[0007] In this case, preferably, the fastening mechanism comprises: a first clamp piece arranged from the tip end side of the valve shaft in the axial direction to straddle between the valve shaft and the first valve plate, and detachably engaged with the first valve plate and detachably fixed to the valve shaft; a second clamp piece arranged from the tip end side of the valve shaft in the axial direction to straddle between the valve shaft and the second valve plate, and detachably engaged with the second valve plate and detachably fixed to the valve shaft; and a first fastening member and a second fastening member that detachably fix the first clamp piece and the second clamp piece to the tip end portion of the valve shaft, respectively; The base end portions of the first and second valve plates in the axial direction are engaged with the tip portion of the valve shaft from the tip side of the valve shaft by a concave-convex engagement, and when the first and second clamp pieces are fixed to the valve shaft by the first and second fastening members, the tip portions of the first and second valve plates are pressed toward their inner surfaces by the engagement between the first and second clamp pieces and the first and second valve plates, and the base end portions of the first and second valve plates are pressed toward their inner surfaces by the concave-convex engagement between the base end portions of the valve plates and the tip portion of the valve shaft, thereby fastening the first and second valve plates to the tip portion of the valve shaft.

[0008] Preferably, the recess-and-projection engagement between the base end side ends of the pair of valve plates and the tip end portion of the valve shaft is formed by engagement between engaging portions provided at the base end portions of the pair of valve plates respectively and a pair of engaged portions provided at the tip end portion of the valve shaft, the engaging portions being either recesses or convex portions engaged therewith, and the engaged portions being the other of the recesses or the convex portions, the first valve plate and the second valve plate being formed with first engaging recesses and second engaging recesses that open towards the tip end side in the axial direction at the longitudinal center of the inner surfaces thereof, and the first clamp piece and the second clamp piece being formed with first engaging protrusions and second engaging protrusions that engage with the first and second engaging recesses, and the first engaging protrusions are engaged with the first engaging recesses and the engaging portions formed on the first valve plate and the valve shaft are engaged with the engaged portions When the first clamp piece is fixed to the valve shaft with the first fastening member, the first engaging protrusion applies a pressing force to the first engaging recess in the direction of the inside of the first valve plate, and the engaging portion applies a pressing force to the engaged portion in the direction of the inside of the first valve plate, thereby fastening the first valve plate to the valve shaft. When the second engaging protrusion is engaged with the second engaging recess, and the engaging portion and the engaged portion formed on the second valve plate and the valve shaft are engaged, the second clamp piece is fixed to the valve shaft with the second fastening member, and the second engaging protrusion applies a pressing force to the second engaging recess in the direction of the inside of the second valve plate, and the engaging portion applies a pressing force to the engaged portion in the direction of the inside of the second valve plate, thereby fastening the second valve plate to the valve shaft.

[0009] Preferably, the first and second fastening members are a first fastening bolt and a second fastening bolt, and the axial tip surface of the valve shaft is provided with threaded holes for threading the fastening bolts, and the first and second clamp pieces are provided with through holes for inserting the first and second fastening bolts, and the first clamp piece is fixed to the valve shaft by inserting the first fastening bolt into the through hole of the first clamp piece and threading it into the threaded hole of the valve shaft, and the second clamp piece is fixed to the valve shaft by inserting the second fastening bolt into the through hole of the second clamp piece and threading it into the threaded hole of the valve shaft.

[0010] Preferably, the first clamp piece has the first engaging protrusion on one end side sandwiching the through hole and a first locking claw on the other end side, and when the first clamp piece is fixed with the first fastening bolt, the first locking claw is locked onto the valve shaft toward the first engaging protrusion side, and the second clamp piece has the second engaging protrusion on one end side sandwiching the through hole and a second locking claw on the other end side, and when the second clamp piece is fixed with the second fastening bolt, the second locking claw is locked onto the valve shaft toward the second engaging protrusion side.

[0011] Furthermore, preferably, when the first fastening bolt is loosened, the first clamp piece is rotatable around the axis of the first fastening bolt between an engagement position in which the first engagement protrusion is engaged with the first engagement recess and a detachment position in which the first engagement protrusion is removed from the first engagement recess, and the first clamp piece is accommodated in a gap between the inner surface of the first valve plate and the inner surface of the second valve plate when the first clamp piece is rotated from the engagement position to the detachment position, and the second clamp piece is rotatable around the axis of the second fastening bolt between an engagement position in which the second engagement protrusion is engaged with the second engagement recess and a detachment position in which the second engagement protrusion is removed from the second engagement recess, and the second clamp piece is accommodated in the gap between the inner surface of the first valve plate and the inner surface of the second valve plate when the second clamp piece is rotated from the engagement position to the detachment position.

[0012] Preferably, the first and second fastening bolts have a shaft portion extending in the axial direction, a head portion provided at the axial tip portion of the shaft portion, and a male thread portion formed on the outer peripheral surface of the shaft portion, and the inner surface of the through hole opened in the first and second clamp pieces has a female thread portion that can be threaded with the male thread portion, and the shaft portion further has a thin-diameter portion on the head side of the male thread portion and whose outer diameter is smaller than the inner diameter of the female thread portion, and the thin-diameter portion is inserted into the through hole, and is configured so that when the first and second fastening bolts are loosened, the head-side end of the male thread portion abuts the female thread portion of the first and second clamp pieces.

[0013] Preferably, the support mechanism includes at least a pair of support bases sandwiched between the first valve plate and the second valve plate at least at both longitudinal ends of the valve plates, a third clamp piece disposed from a tip end side of each of the pair of support bases in the axial direction so as to straddle the first valve plate and the second valve plate, and detachably engaged with the first and second valve plates and detachably fixed to each of the support bases, and a third fastening member detachably fixing the third clamp piece to the tip end portion of the support base in the axial direction, The base end portions of the first and second valve plates in the axial direction are engaged with the support base from the tip side of the support base by projection and recess, and by engaging the third clamp pieces with the first and second valve plates and fixing the third clamp pieces to the support base with the third fastening member while the base end portions of the pair of valve plates and the support base are engaged with projection and recess, the tip and base end portions of the first and second valve plates are respectively pressed toward their inner surfaces, thereby fastening the first and second valve plates and the support base to each other.

[0014] Preferably, the recess-and-protrusion engagement between the base end portions of the pair of valve plates and the support base is formed by engagement between base end engaging recesses provided at the base end portions of the pair of valve plates, respectively, and a pair of base end engaging protrusions provided at the support base, and the first valve plate and the second valve plate are formed with third engaging recesses and fourth engaging recesses that open toward the tip side in the axial direction at least at both ends in the longitudinal direction of the inner surfaces thereof, and the third clamp piece is formed with third engaging protrusions and fourth engaging protrusions that are engaged with the third engaging recesses and fourth engaging recesses, and the third clamp piece is fixed to the support base with the third fastening member while the base-end side engaging recesses formed on the first and second valve plates and the support base are engaged with the base-end side engaging protrusion, whereby the third engaging protrusion applies a pressing force toward the inner surface of the first valve plate to the third engaging recess and the fourth engaging protrusion to the fourth engaging recess, and the base-end side engaging recess applies a pressing force toward the inner surface of the first valve plate to the base-end side engaging protrusion, thereby fastening the first and second valve plates and the support to each other.

[0015] Also, preferably, the third fastening member is a third fastening bolt, and a threaded hole is provided in the axial tip surface of the support base for screwing in the third fastening bolt, and a through hole is provided in the third clamp piece for inserting the third fastening bolt, and the third clamp piece is fixed to the support base by inserting the third fastening bolt into the through hole of the third clamp piece and screwing it into the threaded hole of the support base.

[0016] Preferably, the third engagement recess, the fourth engagement recess and the base-end side engagement recess extend in the longitudinal direction of the valve plate, with their outer ends opening outward in the longitudinal direction, and the support base is configured so that the third engagement protrusion and the fourth engagement protrusion of the third clamp piece are engaged with the third engagement recess and the fourth engagement recess of the first and second valve plates, and the base-end side engagement recess and the base-end side engagement protrusion are engaged, and by loosening the third fastening bolt, the third engagement protrusion and the fourth engagement protrusion are slid along the third engagement recess and the fourth engagement recess, and the base-end side engagement recess is slid along the base-end side engagement protrusion, thereby making it possible to remove the support mechanism from the first and second valve plates.

[0017] Preferably, the third clamp piece is rotatable about the axis of the third fastening bolt from a state in which the third engagement convex portion is engaged with the third engagement recess and the fourth engagement convex portion is engaged with the fourth engagement recess by loosening the third fastening bolt, and the third clamp piece is further formed with a protruding piece portion that protrudes radially from the third fastening bolt as a center, and the protruding piece portion is formed with a fifth engagement convex portion at its protruding tip portion that can engage with the third engagement recess and the fourth engagement recess, and the third engagement convex portion and the fourth engagement convex portion are arranged on both radial sides of the third fastening bolt, and the fifth engagement convex portion is The third clamp piece is arranged at a position perpendicular to the third engagement protrusion and the fourth engagement protrusion around the axis of the third fastening bolt, and the third clamp piece is configured so that, with the third engagement protrusion and the fourth engagement protrusion engaged with the third engagement recess and the fourth engagement recess, by loosening the third fastening bolt and rotating the third clamp piece around the axis of the third fastening bolt, the fifth engagement protrusion engages with the third engagement recess or the fourth engagement recess to lock either the first valve plate or the second valve plate, while at the same time releasing the other of the valve plates from engagement with the third clamp piece.

[0018] Preferably, the third fastening bolt has a shaft portion extending in the axial direction, a head portion provided at the axial tip portion of the shaft portion, and a male thread portion formed on the outer peripheral surface of the shaft portion, and the through hole opened in the third clamp piece has an internal thread portion formed thereon that can be threaded with the male thread portion, and the shaft portion further has a thin-diameter portion on the head side of the male thread portion that has an outer diameter smaller than the inner diameter of the female thread portion, and the thin-diameter portion is inserted into the through hole, and is configured so that when the third fastening bolt is loosened, the head-side end of the male thread portion abuts the female thread portion of the third clamp piece.

[0019] Preferably, the gate valve further comprises the first valve plate and the a valve box that accommodates two valve plates, and the valve box holds the first and second valve plates on the axis; a surrounding side wall and a removably attached portion at the leading end of the side wall in the axial direction; and a top wall attached to the side wall, the first opening and the front second opening being formed in the side wall. The two openings are located opposite each other. [Effects of the Invention]

[0020] As described above, according to the present invention, a pair of valve plates is detachably attached to the valve shaft by directly clamping the tip of the valve shaft between the pair of valve plates and detachably fastening the pair of valve plates and the valve shaft to each other, thereby providing a gate valve that is not only easy to maintain but also enables various costs to be reduced by reducing the weight of the valve plates and the surrounding area. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a perspective view of a gate valve according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a plan view of the gate valve. [Figure 3] 3 is a partial cross-sectional view of the gate valve taken along the line III-III in FIG. 2. [Figure 4] FIG. 4 is an enlarged cross-sectional view of part A in FIG. 3. [Figure 5] 3 is a cross-sectional view of the gate valve taken along the arrows VV in FIG. 2. [Figure 6] FIG. 10 is a perspective view of the gate valve when the second valve plate is replaced. [Figure 7] FIG. 2 is a perspective view of the gate valve with the second valve plate removed from the valve shaft. [Figure 8] FIG. 4 is a plan view of a gate valve according to a second embodiment of the present invention. [Figure 9] 9 is a partial cross-sectional view of the gate valve taken along the line IX-IX in FIG. 8. [Figure 10] 9 is a partial cross-sectional view of the gate valve taken along the arrow XX in FIG. 8. [Figure 11] 10 is a cross-sectional view of the gate valve taken along the line XI-XI in FIG. 8. [Figure 12] FIG. [Figure 13] FIG. 2 is a partial perspective view of a gate valve. [Figure 14] FIG. 2 is a partial perspective view of the gate valve with the first valve plate removed. [Figure 15] FIG. 2 is a partial perspective view of the gate valve with the second valve plate removed. [Figure 16] FIG. 10 is a cross-sectional view of a gate valve according to a third embodiment of the present invention. [Figure 17] FIG. DETAILED DESCRIPTION OF THE INVENTION

[0022] [First embodiment] The gate valve according to the present invention will be described below. As shown in Figures 1, 2, and 3, the gate valve 10 includes a valve shaft 17 extending in the vertical direction (axis L direction), a first valve plate 21 and a second valve plate 22 connected to the valve shaft 17, and an operating mechanism 24 that moves and operates the first valve plate 21 and the second valve plate 22 via the valve shaft 17.

[0023] The operating mechanism 24 has two air cylinders 25, 25 arranged parallel to each other on both the left and right sides of the valve shaft 17, and these air cylinders 25 operate the valve shaft 17 to move the first valve plate 21 and the second valve plate 22.

[0024] The first valve plate 21 and the second valve plate 22 are disposed opposite each other with a gap in the front-rear direction and extend in the left-right direction (longitudinal direction), and these first and second valve plates 21, 22 are formed in the shape of a substantially rectangular plate. In this embodiment, the first valve plate 21 and the second valve plate 22 are formed in an elongated (rectangular) shape in the left-right direction when viewed from the front. Annular seal members 21a, 22a are provided on the outer peripheries of the outer seal surfaces (outer surfaces) 21e, 22e of the first valve plate 21 and the second valve plate 22, respectively.

[0025] A valve shaft 17 is arranged between the first valve plate 21 and the second valve plate 22, and the first valve plate 21 and the second valve plate 22 are removably attached to the valve shaft 17 by a fastening mechanism 30 while abutting against the valve shaft 17, and are removably fastened to each other at both longitudinal ends of the first valve plate 21 and the second valve plate 22 by a support mechanism 50.

[0026] The valve shaft 17 extends upward (toward the tip end in the axial direction) from the operating mechanism 24 and then extends in the vertical direction (direction of the axis L), and on both front-to-rear directions of the upper side of the valve shaft 17, a first side surface portion 17a and a second side surface portion 17b having a rectangular shape are formed facing each other across the axis L, as shown in Fig. 3. In this embodiment, the first side surface portion 17a and the second side surface portion 17b extend parallel to each other, and the first side surface portion 17a contacts the inner surface 21b facing the sealing surface 21e of the first valve plate 21, and the second side surface portion 17b contacts the inner surface 22b facing the sealing surface 22e of the second valve plate 22, and the first valve plate 21 and the second valve plate 22 are arranged side by side in parallel with the valve shaft 17 sandwiched therebetween.

[0027] As shown in FIGS. 2, 3 and 4, the fastening mechanism 30 that fastens the first valve plate 21 and the second valve plate 22 to the valve shaft 17 includes a first engagement recess 36 and a second engagement recess 45 that open toward the axial tip end at the longitudinal center of the inner surfaces 21b, 22b of the first valve plate 21 and the second valve plate 22, a first clamp piece 31 that is attached so as to straddle between the valve shaft 17 and the first valve plate 21 from the axial tip end side of the valve shaft 17 and is releasably engaged with the first valve plate 21 and is detachably fixed to the valve shaft 17, and a second clamp piece 31 that is attached so as to straddle between the valve shaft 17 and the second valve plate 22 from the axial tip end side of the valve shaft 17. the first clamp piece 31 and the second clamp piece 40 are disposed on the valve shaft 17 and are detachably engaged with the second valve plate 22 and detachably fixed to the valve shaft 17, a first fastening bolt 67 (first fastening member) and a second fastening bolt 71 (second fastening member) that secure the first clamp piece 31 and the second clamp piece 40 to the upper end of the valve shaft 17, respectively, lower engagement recesses 26, 27 (engaging portion, recess) provided at the base end side ends of the first valve plate 21 and the second valve plate 22, and a first protrusion 19 and a second protrusion 20 (engaged portion, convex portion) provided at the tip end of the valve shaft 17 and that engage the lower engagement recesses 26, 27 from the tip side of the valve shaft 17. The first engagement recess 36 will be described in detail later.

[0028] An upward-facing shaft end surface 17c is formed at the upper end of the valve shaft 17. In this embodiment, the shaft end surface 17c extends in the left-right direction, and a protrusion 18 extending in the left-right direction and protruding upward is provided in the middle of the shaft end surface 17c in the front-rear direction. A flat surface 18a extending parallel to the shaft end surface 17c is formed at the top of the protrusion 18, and a first inclined surface 18b and a second inclined surface 18c are formed on both the front and rear sides of the protrusion 18, which slope outward as they extend downward. A plurality of female threads 70 (screw holes) are formed in the flat surface 18a at intervals in the left-right direction, and a first fastening bolt 67 and a second fastening bolt 71 inserted through the first clamp piece 31 and the second clamp piece 40 are threadedly engaged into these female threads 70. The first and second clamp pieces 31, 40 are fixed onto the protrusion 18, and the first valve plate 21 and the second valve plate 22 are fastened to the valve shaft 17. The first fastening bolt 67 and the female thread portion 70 will be described in detail later.

[0029] 4, the first clamp piece 31 has a first clamp main body 32 fixed to the shaft end surface 17c (projection 18) via a first fastening bolt 67 (see FIG. 1), and a first engaging protrusion 34 formed on the first valve plate 21 side of the first clamp main body 32 and protruding downward to engage the first valve plate 21. The first clamp main body 32 is formed in a plate shape extending in the front-to-rear direction, and a through hole 32a through which the first fastening bolt 67 is inserted is provided on the second valve plate 22 side (rear side) of the first clamp main body 32, and a male thread portion 68a of the first fastening bolt 67 inserted into this through hole 32a is screwed into a female thread portion 70 (first fastening member) of the valve shaft 17.

[0030] A downwardly protruding main body locking claw (first locking claw) 33 is formed on the side of the first clamp main body 32 facing the second valve plate 22. A third inclined surface 33a is formed on the inner surface of the main body locking claw 33, extending along the second inclined surface 18c of the protrusion 18. That is, the third inclined surface 33a inclines rearward (outward) as it extends downward. Therefore, when the first clamp main body 32 is fastened to the protrusion 18 by the first fastening bolt 67 with the third inclined surface 33a in contact with the second inclined surface 18c, the component force (pressure) of the force acting from the third inclined surface 33a to the second inclined surface 18c causes the third inclined surface 33a to tightly contact the second inclined surface 18c, and the first clamp piece 31 is fastened to the valve shaft 17.

[0031] A first engagement protrusion 34 provided on the first valve plate 21 side of the first clamp body 32 has a fourth inclined surface 34a formed on its inner side that slopes outward as it extends downward. In this embodiment, as shown in FIG. 2, the first clamp piece 31 is formed with two first clamp bodies 32 arranged with a gap in the left-right direction and a connecting portion 35 that connects the front sides of these two first clamp bodies 32 to each other. A first engagement protrusion 34 (see FIG. 4) extends from one left-right end to the other end of the first clamp piece 31 at the lower part of each of the two first clamp bodies 32 and the connecting portion 35 on the first valve plate 21 side. A second clamp body 41 of a second clamp piece 40 (described later) is disposed between the two first clamp bodies 32.

[0032] 2 and 4, a first engagement recess 36 is formed on the inner surface of the first valve plate 21, against which the first clamp piece 31 abuts, recessed forward to engage with the first engagement protrusion 34. The first engagement recess 36 has a first engagement groove 36a at its bottom that is recessed downward from a position forward of the inner surface 21b. In this embodiment, the first engagement recess 36 is formed in an upper part of the inner surface 21b of the first valve plate 21, in the middle in the left-right direction. The first engagement recess 36 opens inward and extends upward to open at the upper end of the first valve plate 21. The first engagement groove 36a of the first engagement recess 36 is formed with a fifth inclined surface 36b that slopes upward toward the valve shaft 17.

[0033] Therefore, when the first clamp piece 31 is fastened to the upper end of the valve shaft 17 with the first fastening bolt 67 and the fourth inclined surface 34a of the first clamp piece 31 is pressed against the fifth inclined surface 36b of the first engagement recess 36, the inward component of the force acting on the fourth inclined surface 34a can fasten the upper part of the first valve plate 21 in a tight contact state against the valve shaft 17 (first side portion 17a).

[0034] Furthermore, the lower end (base end) of the first valve plate 21 is engaged with the tip end of the valve shaft 17 by projections and recesses. Specifically, as shown in FIG. 3 , a lower engagement recess (recess) 26 is formed in the left-right middle portion of the inner side of the bottom surface 21c of the first valve plate 21. The lower engagement recess (recess) 26 is positioned below the first engagement recess 36, recessed upward, and extends in the left-right direction. A sixth inclined surface 26a is formed inside the lower engagement recess 26, inclining outward as it extends upward, and a first protrusion 19 (engaged portion, protrusion) provided on the valve shaft 17 is inserted into the lower engagement recess 26. The first protrusion 19 is formed on a front step 17d that extends forward from the lower end of the first side surface portion 17a of the valve shaft 17. The first protrusion 19 extends in the left-right direction on the front step 17d, and a seventh inclined surface 19a is formed on the inside of the first protrusion 19, inclining outward as it extends upward.

[0035] For this reason, when the first clamp piece 31 is fixed to the upper end of the valve shaft 17 by the first fastening bolt 67, the first valve plate 21 is pressed downward by a component of the force of the fourth inclined surface 34a of the first clamp piece 31 pressing against the fifth inclined surface 36b of the first valve plate 21. Therefore, the sixth inclined surface 26a formed on the lower part of the first valve plate 21 presses against the seventh inclined surface 19a of the valve shaft 17, and the component of the reaction force from the seventh inclined surface 19a tightly fastens the lower side of the first valve plate 21 to the valve shaft 17 (first side surface portion 17a).

[0036] Therefore, by fixing the first clamp piece 31 to the upper end of the valve shaft 17, the first valve plate 21 can be attached in a state where it is in close contact with the first side surface portion 17a of the valve shaft 17.

[0037] As shown in FIG. 4 , the second clamp piece 40 is formed similarly to the first clamp piece 31 and includes a second clamp body 41 fixed to a protrusion 18 formed on the shaft end face 17c via a second fastening bolt 71, and a second engagement protrusion 43 protruding downward from the second valve plate 22 side of the second clamp body 41 to engage with the second valve plate 22. The second clamp body 41 is formed in a plate shape extending in the front-to-rear direction, and a through hole 41a through which the second fastening bolt 71 is inserted is provided at the end of the second clamp body 41 facing the first valve plate 21. The second fastening bolt 71 inserted into this through hole 41a is threadedly engaged with the female thread portion 70 of the valve shaft 17. In this embodiment, the first fastening bolt 67 and the second fastening bolt 71 are hexagon socket head bolts.

[0038] A downwardly protruding body locking claw 42 is formed on the end of the second clamp body 41 on the first valve plate 21 side (front side). An eighth inclined surface 42a is formed on the inner surface of the body locking claw 42, extending along the first inclined surface 18b of the protrusion 18 formed on the upper end of the valve shaft 17. That is, the eighth inclined surface 42a slopes forward (outward) as it extends downward. Therefore, when the second clamp body 41 is fixed to the protrusion 18 with the second fastening bolt 71 while the eighth inclined surface 42a is in contact with the first inclined surface 18b, a component of the force acting from the eighth inclined surface 42a to the first inclined surface 18b causes the eighth inclined surface 42a to tightly contact the first inclined surface 18b, thereby fastening the second clamp piece 40 to the valve shaft 17.

[0039] The second engagement protrusion 43 has a ninth inclined surface 43a formed on its inner side, which slopes outward (rearward) as it extends downward. In this embodiment, as shown in FIG. 2, the second clamp piece 40 is formed with two second clamp main bodies 41 spaced apart in the left-right direction and a connecting portion 44 connecting the second valve plate 22 sides (rear sides) of the two second clamp main bodies 41. A second engagement protrusion 43 (see FIG. 4) extends from one left-right end to the other end of the second clamp piece 40 at the lower part of the second valve plate 22 side of each of the two second clamp main bodies 41 and the connecting portion 44. The first clamp main body 32 of the first clamp piece 31 is disposed between the two second clamp main bodies 41.

[0040] 2 and 4, a second engagement recess 45 is formed on the inner surface 22b of the second valve plate 22 with which the second clamp piece 40 comes into contact. The second engagement recess 45 is recessed rearward and engages with the second engagement protrusion 43. The second engagement recess 45 has a second engagement groove 45a at its bottom that is recessed downward from a position rearward of the inner surface 22b. In this embodiment, the second engagement recess 45 is formed in an upper part of the inner surface 22b of the second valve plate 22, in the middle in the left-right direction. The second engagement recess 45 opens inward and extends upward to open at the upper end of the second valve plate 22. The second engagement groove 45a of the second engagement recess 45 is formed with a tenth inclined surface 45b that slopes upward toward the valve shaft 17.

[0041] Therefore, when the second clamp piece 40 is fixed to the upper end (protrusion portion 18) of the valve shaft 17 with the second fastening bolt 71 and the ninth inclined surface 43a of the second clamp piece 40 is pressed against the tenth inclined surface 45b of the second engagement recess 45, the inward component of the force acting on the tenth inclined surface 45b can tightly fasten the upper part of the second valve plate 22 to the valve shaft 17 (second side portion 17b).

[0042] Furthermore, the lower end (base end) of the second valve plate 22 is engaged with the tip end of the valve shaft 17 by projections and recesses. Specifically, as shown in FIG. 3, a lower engagement recess 27 is formed on the inside of the bottom surface 22c of the second valve plate 22, positioned below the second engagement recess 45 and recessed upward. An eleventh inclined surface 27a is formed on the inside of this lower engagement recess 27, inclining outward as it extends upward. A second protrusion 20 (engaged portion, protrusion) provided on the valve shaft 17 is inserted into this lower engagement recess 27. The second protrusion 20 is formed on a rear step 17e extending rearward from the lower end of the second side surface portion 17b of the valve shaft 17. The second protrusion 20 extends in the left-right direction on the rear step 17e, and a twelfth inclined surface 20a is formed on the inside of the second protrusion 20, inclining outward as it extends upward.

[0043] For this reason, when the second clamp piece 40 is fixed to the upper end of the valve shaft 17 by the second fastening bolt 71, the second valve plate 22 is pressed downward by a component of the force of the ninth inclined surface 43a of the second clamp piece 40 pressing against the tenth inclined surface 45b of the second valve plate 22. Therefore, the eleventh inclined surface 27a formed on the lower part of the second valve plate 22 presses against the twelfth inclined surface 20a of the valve shaft 17, and the component of the reaction force from the twelfth inclined surface 20a can fasten the lower side of the second valve plate 22 in close contact with the valve shaft 17 (second side surface portion 17b).

[0044] Therefore, by fixing the second clamp piece 40 to the upper end of the valve shaft 17, the second valve plate 22 can be attached in a state where it is in close contact with the valve shaft 17.

[0045] Here, the first and second fastening bolts 67, 71 and the female threaded portion 70 will be described. Since the first and second fastening bolts 67, 71 are identical, only the second fastening bolt 71 will be described. As shown in FIG. 4 , the second fastening bolt 71 includes a shaft portion 68 extending along the axis L, a head portion 69 provided at the upper end of the shaft portion 68, and a male threaded portion 68a formed on the outer periphery of the lower side of the shaft portion 68. Above the male threaded portion 68a, the shaft portion 68 is provided with a thin-diameter portion (non-threaded portion) 68b that does not have the male threaded portion 68a. The thin-diameter portion 68b has a smaller diameter than the outer diameter of the male threaded portion 68a and is also smaller in diameter than the female threaded portion 70 provided on the inner surface of the through-hole 41a of the second clamp piece 40. That is, the female threaded portion 70 is provided on the inner surface of the hole portion 18d extending downward from the flat portion 18a of the protrusion portion 18 and on the upper portion of the inner surface of the through-hole 41a provided in the second clamp main body portion 41. Similar to the second clamp body 41, the first clamp body 32 is also provided with a female thread 70.

[0046] By rotating this second fastening bolt 71 to one side around the axis and threading the male threaded portion 68a into the female threaded portion 70, the second clamp piece 40 can be fixed to the upper end of the valve shaft 17 with the head 69 of the second fastening bolt 71 pressed against the upper surface of the second clamp piece 40.

[0047] On the other hand, when the second clamp piece 40 is to be loosely fastened to the valve shaft 17, the second fastening bolt 71 is rotated in the other direction around the axis, and the shaft portion 68 is moved upward along the female thread portion 70. At this time, when the small-diameter portion 68b moves within the female thread portion 70 of the second clamp piece 40, the upper end of the male thread portion 68a abuts against the lower end of the female thread portion 70 of the second clamp piece 40, pressing the second clamp piece 40 upward. Therefore, as the second fastening bolt 71 moves upward, the second engagement protrusion 43 of the second clamp piece 40 is disengaged from the second engagement groove 45a of the second engagement recess 45, and the engagement of the second clamp piece 40 with the second valve plate 22 is released.

[0048] Here, the axial length of the male thread portion 68a needs to be greater than the axial movement distance required for the second engagement protrusion 43 to be removed from the second engagement groove 45a. Therefore, when the engagement of the second clamp piece 40 with the second valve plate 22 is released, the male thread portion 68a is in a state of being threaded into the female thread portion 70 on the valve shaft 17 side. 2 Fastening bolt 71 This can prevent the valve shaft 17 from being removed and falling or being lost.

[0049] Furthermore, the third fastening bolt 72 and the female thread portion 70 provided in the support mechanism 50 shown in FIG. 5 are similar to the first and second fastening bolts 67, 71 and the female thread portion 70 provided in the fastening mechanism 30 described above, and therefore the third fastening bolt 72 and the female thread portion 70 of the support mechanism 50 are given the same reference numerals and their description will be omitted.

[0050] Next, the support mechanism 50 will be described. As shown in Figures 5 and 6, the support mechanism 50 has a third engagement recess 64 and a fourth engagement recess 66 provided on the inner surfaces 21b, 22b of the first valve plate 21 and the second valve plate 22, a support base 51 arranged between both left and right sides of the first valve plate 21 and the second valve plate 22, a third clamp piece 60 arranged at the upper end of the support base 51 and engaged with the third engagement recess 64 and the fourth engagement recess 66, a third fastening bolt 72 (third fastening member) that detachably fixes the third clamp piece 60 to the support base 51, lower engagement recesses (base end engagement portion, recess) 28, 29 provided at the base end ends on both longitudinal ends of the first valve plate 21 and the second valve plate 22, and a third protrusion portion 53 and a fourth protrusion portion (base end engagement protrusion, protrusion) 54 that are provided on the support base 51 and engage with the lower engagement recesses 28, 29 from the tip side of the support base 51.

[0051] The support base 51 has a support end surface 51c at its upper end, which is formed as a flat surface facing upward, and is formed as a rectangular parallelepiped extending in the vertical direction. A first contact surface portion 51a and a second contact surface portion 51b are formed on both sides of the support base 51 in the front-to-rear direction, and come into contact with the inner surfaces 21b and 22b of the first valve plate 21 and the second valve plate 22, respectively. A hole portion 55 extending downward is provided in the center of the support end surface 51c, and a female thread portion 70 (screw hole) is formed on the inner surface of this hole portion 55. A third fastening bolt 72 for fixing the third clamp piece 60 to the support base 51 is screwed into this female thread portion 70.

[0052] The lower ends (base end ends) of the first and second valve plates 21, 22 are engaged with the support base 51 from the tip end side of the support base 51 by projections and recesses. Specifically, as shown in FIG. 5 , a front step 51d that protrudes forward and extends in the left-right direction is formed at the lower part of the first contact surface 51a of the support base 51, and a third protrusion 53 that protrudes upward and extends in the left-right direction is formed at the tip end (front end) of this front step 51d. A thirteenth inclined surface 53a that inclines outward (toward the front) as it extends upward is formed on the inner surface of the third protrusion 53. The third protrusion 53 is inserted into a lower engagement recess 28 formed in the bottom surface of the first valve plate 21, and the lower end of the first valve plate 21 is engaged with the support base 51 from the tip end side of the support base 51 by projections and recesses.

[0053] The lower engagement recesses 28 are formed on both left and right sides of the bottom surface 21c of the first valve plate 21, extend in the left and right direction, and the outer left and right ends of the lower engagement recesses 28 open to the left and right ends of the first valve plate 21. In other words, the lower engagement recesses 28 open facing downward and also open to the left and right ends of the first valve plate 21. A fourteenth inclined surface 28a is formed on the inside of the lower engagement recess 28, which inclines outward (toward the front) as it extends upward.

[0054] Meanwhile, a rear step 51e is formed on the lower part of the second contact surface portion 51b of the support base 51, protruding toward the second valve plate 22 (rear side) and extending in the left-right direction. An upwardly protruding fourth protrusion 54 is formed on the outer end of the rear step 51e, and a fifteenth inclined surface 54a is formed on the inner surface of this fourth protrusion 54, which inclines outward (rear side) as it extends upward. This fourth protrusion 54 is inserted into a lower engagement recess 29 formed on the bottom surface 22c of the second valve plate 22, and the lower end of the second valve plate 22 is engaged with the support base 51 from the tip side of the support base 51 in a concave-convex manner.

[0055] The lower engagement recesses 29 are formed on both left and right sides of the bottom surface 22c of the second valve plate 22, extend in the left and right direction, and the outer left and right ends of the lower engagement recesses 29 open at the left and right ends of the second valve plate 22. In other words, the lower engagement recess 29 opens downward and also at the left and right ends of the second valve plate 22. A sixteenth inclined surface 29a is formed on the inside of the lower engagement recess 29, which inclines outward (rearward) as it extends upward.

[0056] Next, the third clamp piece 60 will be described. As shown in Fig. 5 , the third clamp piece 60 has a third clamp main body 61 that is fixed to the support end surface 51c of the support base 51 by a third fastening bolt 72 and extends in the front-to-rear direction with the third fastening bolt 72 at the center, and a third engaging protrusion 62 and a fourth engaging protrusion 63 that are formed at both front-to-rear end portions of the third clamp main body 61 and protrude towards the first valve plate 21 side and the second valve plate 22 side to engage with the first valve plate 21 and the second valve plate 22.

[0057] The third clamp main body 61 is formed in a plate shape extending in the front-rear direction, and both front-rear sides of the third clamp main body 61 extend outward from the first contact surface 51a and the second contact surface 51b of the support base 51. A through hole 61a extending in the up-down direction is provided in the center of the third clamp main body 61 in the front-rear direction, and a female thread portion (screw hole) 70 is provided on the inner surface of this through hole 61a. Furthermore, a hole portion 55 extending downward is provided in the support end surface 51c of the support base 51, and a female thread portion (screw hole) 70 is provided on the inner surface of this hole portion 55. That is, the female thread portion 70 is provided on the inner surface of each of the through hole 61a and the hole portion 55. In this embodiment, the female thread portion 70 provided on the inner surface of the through hole 61a is formed from the lower part to the upper part of the inner surface of the through hole 61a.

[0058] The third engagement protrusion 62 protrudes downward from the front end of the third clamp body 61, and a seventeenth inclined surface 62a is formed on the inside thereof, inclining outward as it extends downward. A third engagement recess 64 is formed on the inner surface 21b of the first valve plate 21, with which the third engagement protrusion 62 comes into contact, and is recessed forward to engage the third engagement protrusion 62.

[0059] The third engagement recess 64 has a third engagement groove 64a whose bottom is recessed downward, and the third engagement groove 64a is formed with an eighteenth inclined surface 64b that slopes upward toward the valve shaft 17. In this embodiment, the third engagement recess 64 extends in the left-right direction on both left-right sides of the first valve plate 21 and is open at both left-right ends and at the upper end (see FIG. 6).

[0060] When the third clamp piece 60 configured in this manner is fixed to the upper end of the support base 51 with the third fastening bolt 72, as shown in Figure 5, the 17th inclined surface 62a of the third engagement protrusion 62 is pressed against the 18th inclined surface 64b of the third engagement recess 64, and the component of the force acting on the 18th inclined surface 64b tightly fastens the upper part of the first valve plate 21 to the support base 51.

[0061] Furthermore, when the third clamp piece 60 is fixed to the upper end of the support base 51 with the third fastening bolt 72, the first valve plate 21 is pressed downward via the third clamp piece 60. Therefore, the fourteenth inclined surface 28a formed on the lower part of the first valve plate 21 is pressed against the thirteenth inclined surface 53a of the valve shaft 17, and the lower side (the base end side end) of the first valve plate 21 is tightly fastened to the support base 51 by a component of the reaction force from the thirteenth inclined surface 53a.

[0062] On the other hand, the fourth engagement protrusion 63 of the third clamp piece 60 protrudes downward from the rear end of the third clamp body 61, and a nineteenth inclined surface 63a is formed on the inside thereof, inclining outward as it extends downward. The inner surface of the second valve plate 22 with which the fourth engagement protrusion 63 abuts is formed with a fourth engagement recess 66 that is recessed rearward and engages the fourth engagement protrusion 63.

[0063] The fourth engagement recess 66 has a fourth engagement groove 66a whose bottom is recessed downward. The fourth engagement groove 66a is formed with a 21st inclined surface 66b that slopes upward toward the valve shaft 17. In this embodiment, the fourth engagement recess 66 extends in the left-right direction on both left-right sides of the second valve plate 21 and is open at both left-right ends and at the upper end.

[0064] Therefore, as shown in Figure 5, when the third clamp piece 60 is fixed to the upper end of the support base 51 with the third fastening bolt 72 and the 19th inclined surface 63a of the fourth engagement protrusion 63 is pressed against the 21st inclined surface 66b of the fourth engagement recess 66, the component of the force acting on the 21st inclined surface 66b can fasten the upper part of the second valve plate 22 in close contact with the support base 51.

[0065] Furthermore, when the third clamp piece 60 is fixed to the upper end of the support base 51 with the third fastening bolt 72, the second valve plate 22 is pressed downward via the third clamp piece 60. Therefore, the sixteenth inclined surface 29a formed on the lower part of the second valve plate 22 is pressed against the fifteenth inclined surface 54a of the support base 51, and the component of the reaction force from the fifteenth inclined surface 54a tightly fastens the lower side of the second valve plate 22 to the support base 51. Therefore, by fixing the third clamp piece 60 to the upper end of the support base 51 with the third fastening bolt 72, the first valve plate 21 and the second valve plate 22 can be fastened to each other via the support base 51.

[0066] As described above, the third engagement recess 64 and the fourth engagement recess 66 formed in the upper part of each of the first valve plate 21 and the second valve plate 22, and the lower engagement recesses 28, 29 formed in the lower part, extend outward in the left-right direction and open at their outer ends in the left-right direction. Therefore, when the third clamp piece 60 is engaged with the third engagement recess 64 and the fourth engagement recess 66 and the third protrusion 53 and the fourth protrusion 54 are engaged with the lower engagement recesses 28, 29, loosening the third fastening bolt 72 relieves the pressure of the third clamp piece 60 against the first valve plate 21 and the second valve plate 22. Therefore, when the support base 51 is pressed outward in the left-right direction against the first valve plate 21 and the second valve plate 22, the third engagement convex portion 62 and the fourth engagement convex portion 63 slide along the third engagement recess 64 and the fourth engagement recess 66, and the third protrusion portion 53 and the fourth protrusion portion 54 slide along the lower engagement recesses 28, 29, allowing the support mechanism 50 to be removed from the first and second valve plates 21, 22.

[0067] Next, a case where one of the first valve plate 21 and the second valve plate 22 attached to the valve shaft 17 is removed will be described. In this embodiment, a case where the second valve plate 22 is removed will be described. As shown in FIG. 6 , first, in one of the two support bases 51 attached to the first valve plate 21 and the second valve plate 22, the third fastening bolt 72 that secures the third clamp piece 60 is rotated to relieve the pressure on the third clamp piece 60 against the first valve plate 21 and the second valve plate 22. This relieves the pressure on the third engagement protrusion 62 and the fourth engagement protrusion 63 of the third clamp piece 60 against the third engagement recess 64 and the fourth engagement recess 66, allowing the support base 51 to slide relative to the first valve plate 21 and the second valve plate 22. Similarly to the one support base 51, the other support base 51 is also brought into a state where it can slide.

[0068] Then, one of the support bases 51 is removed by sliding it outward in the left-right direction together with the third clamp piece 60 relative to the first valve plate 21 and the second valve plate 22. Similarly, the other support base 51 is removed by sliding it outward in the left-right direction relative to the first valve plate 21 and the second valve plate 22.

[0069] Then, the second fastening bolt 71 inserted through the second clamp piece 40 is rotated to release the second fastening bolt 71 from the female thread portion 70 provided on the valve shaft 17, and the second clamp piece 40 is removed from the valve shaft 17. Then, when the second valve plate 22 is pulled upward, the second protrusion portion 20 (see FIG. 3) of the valve shaft 17 is removed from the lower engagement recess 27 (see FIG. 3) provided on the bottom surface of the second valve plate 22, and the fourth protrusion portion 54 (see FIG. 5) of the valve shaft 17 is removed from the lower engagement recess 29 (see FIG. 5), and the second valve plate 22 is removed from the valve shaft 17. Therefore, as shown in FIG. 7, the second valve plate 22 is removed from the gate valve 10, and only the first valve plate 21 is attached.

[0070] Next, the attachment of the second valve plate 22 to the valve shaft 17 will be described. First, as shown in FIGS. 3 and 5 , the second protrusion 20 of the valve shaft 17 is inserted into the lower engagement recess 27 of the second valve plate 22, and the fourth protrusion 54 is inserted into the lower engagement recess 29. Then, the second valve plate 22 is tilted toward the valve shaft 17, so that the inner surface 22b of the second valve plate 22 comes into contact with the second side surface 17b of the valve shaft 17. Then, with the second engagement protrusion 43 of the second clamp piece 40 inserted into the second engagement recess 45, the second clamp piece 40 is fixed to the upper end of the valve shaft 17 with the second fastening bolt 71. As a result, the second valve plate 22 is fastened to the valve shaft 17 in a tight contact state.

[0071] Then, with the third fastening bolt 72 inserted through the third clamp piece 60 attached to the upper ends of each of the two support bases 51, 51 loosened, the support base 51 is moved from the outer left-right ends of the first valve plate 21 and the second valve plate 22 toward the valve shaft 17, as shown in Figures 5 and 6, so that the third protrusion portion 53 and the fourth protrusion portion 54 of the support base 51 are inserted into the lower engagement recesses 28, 29 formed in the lower parts of the first valve plate 21 and the second valve plate 22, and the third engagement protrusion portion 62 and the fourth engagement protrusion portion 63 of the third clamp piece 60 are inserted into the third engagement recess 64 and the fourth engagement recess 66 of the first valve plate 21 and the second valve plate 22.

[0072] Then, one support base 51 is slid toward the valve shaft 17 and moved to a predetermined position relative to the first valve plate 21 and the second valve plate 22. Then, the third fastening bolt 72 is tightly fastened to the third clamp piece 60, fastening one side of the first valve plate 21 and the second valve plate 22 to each other in the left-right direction via the support base 51. Then, the other support base 51, like the one support base 51, fastens the other side of the first valve plate 21 and the second valve plate 22 to each other in the left-right direction via the support base 51. Thus, the second valve plate 22 is attached to the valve shaft 17.

[0073] In this way, the gate valve 10 according to this embodiment has the tip of the valve shaft 17 directly sandwiched between the first valve plate 21 and the second valve plate 22, and the pair of valve plates 21, 22 and the valve shaft 17 are removably fastened to each other, thereby detachably attaching the pair of valve plates 21, 22 to the valve shaft 17. Therefore, it is possible to provide a gate valve 10 that not only has excellent workability during maintenance of the valve plates 21, 22, but also enables various costs to be reduced by reducing the weight around the valve plates 21, 22.

[0074] Furthermore, in the gate valve 10 according to this embodiment, the first valve plate 21 and the second valve plate 22 can be attached to and detached from the valve shaft 17 by tightening or loosening the first and second fastening bolts 67, 71 inserted through the first clamp piece 31 and the second clamp piece 40. Furthermore, in the gate valve 10 according to this embodiment, the support base 51 can be detached from the first valve plate 21 and the second valve plate 22, and the first valve plate 21 and the second valve plate 22 can be connected to each other simply by tightening or loosening the third fastening bolt 72, without removing the third clamp piece 60 or the third fastening bolt 72 from the support base 51. Therefore, in the gate valve 10 according to this embodiment, the first valve plate 21 and the second valve plate 22 can be easily attached to and detached from the valve shaft 17, improving the workability during maintenance of the valve plates 21, 22.

[0075] Furthermore, the first, second and third fastening bolts 67, 71 and 72 that fasten the first clamp piece 31, the second clamp piece 40 and the third clamp piece 60 together are configured to be able to prevent removal from these clamp pieces 31, 40 and 60, and are configured so that when these fastening bolts 67, 71 and 72 are rotated in a direction that loosens the fastening, these clamp pieces 31, 40 and 60 move upward together with the fastening bolts 67, 71 and 72. Therefore, when the locking of these clamp pieces 31, 40 and 60 is released, the fastening bolts 67, 71 and 72 can be prevented from falling or being lost, making it easier to replace the first valve plate 21 and the second valve plate 22.

[0076] [Second embodiment] Next, a second embodiment of the gate valve 10 according to the present invention will be described. In the second embodiment, differences from the first embodiment will be mainly described, and the same parts as those in the first embodiment will be assigned the same reference numerals and descriptions thereof will be omitted.

[0077] As shown in Figures 8, 9, and 10, there are two protrusions 18 provided on the shaft end surface 17c of the valve shaft 17, spaced apart in the left-right direction, one of which secures the first clamp piece 31 and the other of which secures the second clamp piece 40.

[0078] The first clamp piece 31 and the second clamp piece 40 are rotatably attached to the upper end of the valve shaft 17, and the third clamp piece 60 is rotatably attached to the upper end of the support base 51. Specifically, the first clamp piece 31 is rotatable about the axis of a first fastening bolt 67 fixed to the valve shaft 17 when the fastening of the first fastening bolt 67 is loosened, the second clamp piece 40 is rotatable about the axis of a second fastening bolt 71 fixed to the valve shaft 17 when the fastening of the second fastening bolt 71 is loosened, and the third clamp piece 60 is rotatable about the axis of a third fastening bolt 72 fixed to the support base 51 when the fastening of the third fastening bolt 72 is loosened.

[0079] 8 and 9, the first engagement recess 36 formed on the inner surface 21b of the first valve plate 21 that the first clamp piece 31 faces has a first extended recess 36c that is recessed so that the first engagement protrusion 34 (tip end) of the first clamp piece 31 on the first valve plate 21 side does not come into contact with the first engagement recess 36 when the first clamp piece 31 is rotated around the axis of the first fastening bolt 67. In this embodiment, the first extended recess 36c is formed from the bottom surface to the upper end of the first engagement recess 36, and is formed in an arc shape that passes radially outward of the rotation trajectory of the tip end when the first clamp piece 31 is rotated around the axis of the first fastening bolt 67 in a plan view.

[0080] In addition, when the first clamp piece 31 is rotated, the rear end of the first clamp piece 31 is arranged so as not to come into contact with the second clamp piece 40 disposed adjacent to it in the left-right direction. Piece 31 and the second clamp 40 pieces are arranged with a predetermined gap Y in the left-right direction. Therefore, the first clamp piece 31 can rotate around the axis of the first fastening bolt 67 without coming into contact with the second clamp piece 40. When the first fastening bolt 67 is loosened, the first clamp piece 31 can rotate freely around the axis of the first fastening bolt 67 between an engagement position P1 (see FIG. 8) where the first engagement protrusion 34 is engaged with the first engagement recess 36, and a detachment position P2 (see FIG. 14) where the first engagement protrusion 34 is removed from the first engagement recess 36. When the first clamp piece 31 is rotated to the detachment position P2, it moves into the gap 47 (see FIG. 8) between the first valve plate 21 and the second valve plate 22.

[0081] 8 and 10, the second engagement recess 45 formed on the inner surface 22b of the second valve plate 22 that the second clamp piece 40 faces has a second extension recess 45c that is recessed so that the second engagement protrusion 43 (tip) of the second clamp piece 40 on the second valve plate 22 side does not come into contact with the second engagement recess 45 when the second clamp piece 40 is rotated around the axis of the second fastening bolt 71. In this embodiment, the second extension recess 45c is formed from the middle position of the second engagement recess 45 in the up-down direction to the upper end, and in a plan view, 2 Fastening bolt 71 The second clamp piece 40 is formed in an arc shape that passes radially outward of the rotation path of the tip of the second clamp piece 40 when the second clamp piece 40 is rotated about the axis of the second clamp piece 40. Therefore, the second clamp piece 40 can rotate without contacting the first clamp piece 31. Similarly to the first clamp piece 31, when the second fastening bolt 71 is loosened, the second clamp piece 40 can rotate freely about the axis of the second fastening bolt 71 between an engagement position P1 (see FIG. 8) where the second engagement protrusion 43 is engaged with the second engagement recess 45, and a detachment position P2 (see FIG. 15) where the second engagement protrusion 43 is disengaged from the second engagement recess 45. When the second clamp piece 40 is rotated to the detachment position P2, it moves into the gap 47 (see FIG. 8) between the first valve plate 21 and the second valve plate 22.

[0082] 8 and 11, the third engagement recess 64 and the fourth engagement recess 66 formed on the inner surfaces 21b, 22b of the first valve plate 21 and the second valve plate 22, respectively, that the third clamp piece 60 faces, have third extended recesses 64d and fourth extended recesses 66d recessed outward in the front-to-rear direction. That is, when the third clamp piece 60 is rotated around the axis of the first fastening bolt 67 in a state in which the third engagement protrusion 62 and the fourth engagement protrusion 63 of the third clamp piece 60 are removed upward from the third engagement groove 64a and the fourth engagement groove 66a, the third engagement recess 64 and the fourth engagement recess 66 have the third extended recess 64d recessed so that the third engagement protrusion 62 (tip end) of the third clamp piece 60 does not come into contact with the third engagement recess 64, and the fourth extended recess 66d recessed so that the fourth engagement protrusion 63 (tip end) of the third clamp piece 60 does not come into contact with the fourth engagement recess 66.

[0083] As shown in FIGS. 8 , 12 , and 14 , the third clamp piece 60 has a protruding piece 61 b protruding from one side surface 61 c of the third clamp main body 61, and a fifth engaging protrusion 65 that can engage with the third engaging recess 64 and the fourth engaging recess 66 is formed at the tip of the protruding piece 61 b. That is, the third clamp piece 60 has the fifth engaging protrusion 65 in addition to the third engaging protrusion 62 and the fourth engaging protrusion 63. The third engaging protrusion 62 and the fourth engaging protrusion 63 are arranged on both radial sides of the rotation center of the third fastening bolt 72 in a plan view, and the fifth engaging protrusion 65 is arranged in a position shifted by 90° around the axis of the first fastening bolt 67 relative to the third engaging protrusion 62 and the fourth engaging protrusion 63. Furthermore, the third engaging protrusion 62, the fourth engaging protrusion 63, and the fifth engaging protrusion 65 are arranged in positions that have the same rotation radius r with respect to the rotation center of the third clamp piece 60.

[0084] 8, when the third clamp piece 60 is rotated to, for example, release the engagement with the first valve plate 21 while the third engagement protrusion 62 and the fourth engagement protrusion 63 are engaged with the third engagement recess 64 and the fourth engagement recess 66, the engagement with the second valve plate 22 is also released. Therefore, by providing a fifth engagement protrusion 65 at a position offset by 90° around the axis from the third engagement protrusion 62 and the fourth engagement protrusion 63, when the engagement with the first valve plate 21 is released, the fifth engagement protrusion 65 can be engaged with the fourth engagement recess 66, thereby engaging the third clamp piece 60 with the second valve plate 22 (see FIG. 14).

[0085] As shown in FIG. 9 , the first side surface portion 17a and the second side surface portion 17b of the valve shaft 17 are provided with positioning pins 74a and 74b, respectively, that protrude outward in the front-to-rear direction. In this embodiment, the positioning pin 74a fits into a positioning groove 21d provided in the first valve plate 21, and the positioning pin 74b fits into a positioning groove 22d provided in the second valve plate 22. The positioning pin 74a is provided in the lower part of the first side surface portion 17a, and the positioning pin 74b is provided in the lower part of the second side surface portion 17b. The positioning grooves 21d and 22d open to the bottom surfaces of the first valve plate 21 and the second valve plate 22, respectively, and extend linearly upward, opening toward the valve shaft 17. Therefore, by inserting the positioning pin 74a into the positioning groove 21d, the first valve plate 21 can be positioned relative to the valve shaft 17 in the left-to-right direction. Furthermore, by inserting the positioning pin 74b into the positioning groove 22d, the second valve plate 22 can be positioned relative to the valve shaft 17 in the left-right direction.

[0086] Next, a case where one of the first valve plate 21 and the second valve plate 22 attached to the valve shaft 17 is removed will be described. In this embodiment, first, a case where the first valve plate 21 is removed will be described. As shown in FIG. 11 , first, the third fastening bolts 72 of the third clamp pieces 60 attached to each of the two support bases 51 are rotated in a direction to loosen them. Then, as the third fastening bolts 72 are rotated, the third clamp pieces 60 move upward, and the third engagement protrusions 62 are removed from the third engagement grooves 64a of the third engagement recesses 64, and the fourth engagement protrusions 63 are removed from the fourth engagement grooves 66a of the fourth engagement recesses 66. Then, as shown in Figure 14, when viewed in a plane, each of the two third clamp pieces 60, 60 arranged on the left and right is rotated around its axis to disengage the third engagement protrusion 62 from the third engagement recess 64, disengage the fourth engagement protrusion 63 from the fourth engagement recess 66, and further engage the fifth engagement protrusion 65 with the fourth engagement recess 66.

[0087] 9 is rotated in a direction to loosen the first fastening bolt 67 of the first clamp piece 31 attached to the valve shaft 17. As the first fastening bolt 67 rotates, the first clamp piece 31 moves upward, and the first engagement protrusion 34 is removed from the first engagement groove 36a of the first engagement recess 36. Then, as shown in FIG. 14, the first clamp piece 31 is rotated clockwise in a plan view, and the first engagement protrusion 34 is removed from the first engagement recess 36. As a result, when the first valve plate 21 is lifted upward relative to the valve shaft 17, the first valve plate 21 can be removed from the valve shaft 17 and the support base 51.

[0088] Next, the attachment of the first valve plate 21 to the valve shaft 17 will be described. First, as shown in Fig. 14, the first valve plate 21 is disposed opposite the second valve plate 22 with the inner surface 21b of the first valve plate 21 facing the valve shaft 17. Then, the first protrusion 19 of the valve shaft 17 is inserted into the lower engagement recess 26 of the first valve plate 21 (see Fig. 9), and at the same time, the third protrusions 53 provided on the lower parts of the two support bases 51 are inserted into the lower engagement recesses 28 of the first valve plate 21 (see Fig. 11). Then, the inner surface 21b of the first valve plate 21 is brought into contact with the first side surface portion 17a of the valve shaft 17, and the positioning pin 74a is inserted into the positioning groove 21d provided in the inner surface 21b of the first valve plate 21 (see Fig. 9).

[0089] 9 and 14, the first clamp piece 31 is rotated around the axis of the first fastening bolt 67 to insert the first engagement protrusion 34 into the first engagement recess 36. When the first fastening bolt 67 is then tightly fastened to the valve shaft 17, the first engagement protrusion 34 is engaged in the first engagement groove 36a, and the first valve plate 21 is fastened in a state of close contact with the first side surface portion 17a of the valve shaft 17 via the first clamp piece 31.

[0090] 11 and 14 , when the third clamp piece 60 attached to the upper end of one (for example, the left side) of the two support bases 51 is rotated around the axis of the third fastening bolt 72, the engagement state of the fifth engagement protrusion 65 with the second valve plate 22 is released, and then the fourth engagement protrusion 63 is inserted into the fourth engagement recess 66 and the third engagement protrusion 62 is inserted into the third engagement recess 64. When the third fastening bolt 72 is tightly fastened to the valve shaft 17, the fourth engagement protrusion 63 engages with the fourth engagement groove 66a and the third engagement protrusion 62 engages with the third engagement groove 64a, and the first valve plate 21 and the second valve plate 22 are fastened to each other via the third clamp piece 60 with the support base 51 sandwiched between the first valve plate 21 and the second valve plate 22 on one left-right side of the first valve plate 21 and the second valve plate 22.

[0091] Then, by operating the other of the two support bases 51 in the same manner as the one support base 51 described above, the first valve plate 21 and the second valve plate 22 are fastened to each other via the third clamp piece 60 in a state in which the support base 51 is sandwiched between the first valve plate 21 and the second valve plate 22 on the other left-right side of the first valve plate 21 and the second valve plate 22. As a result, as shown in Fig. 13, the first valve plate 21 can be attached to the valve shaft 17 in a state in which the first valve plate 21 and the second valve plate 22 are fastened to each other.

[0092] Next, the removal of the second valve plate 22 will be described. As shown in FIG. 11 , first, the third fastening bolts 72 of the third clamp pieces 60 attached to each of the two support bases 51 are rotated in a direction to loosen them. As the third fastening bolts 72 are rotated, the third clamp pieces 60 move upward, and the third and fourth engagement protrusions 62, 63 are disengaged from the third and fourth engagement grooves 64a, 66a. Then, as shown in FIG. 15 , each of the two third clamp pieces 60 arranged on the left and right in a plan view is rotated about its axis to disengage the third engagement protrusion 62 from the third engagement recess 64, disengage the fourth engagement protrusion 63 from the fourth engagement recess 66, and further engage the fifth engagement protrusion 65 with the third engagement recess 64.

[0093] 10, the second fastening bolt 71 of the second clamp piece 40 attached to the valve shaft 17 is rotated in a loosening direction. As the second fastening bolt 71 rotates, the second clamp piece 40 moves upward, and the second engagement protrusion 43 is removed from the second engagement groove 45a of the second engagement recess 45. Then, as shown in FIG. 15, the second clamp piece 40 is rotated clockwise in a plan view, and the second engagement protrusion 43 is removed from the second engagement recess 45. As a result, the second valve plate 22 is lifted upward relative to the valve shaft 17, and the second valve plate 22 can be removed from the valve shaft 17 and the support base 51.

[0094] Next, the attachment of the second valve plate 22 to the valve shaft 17 will be described. First, as shown in Fig. 15, the second valve plate 22 is disposed opposite the first valve plate 21 with the inner surface 22b of the second valve plate 22 facing the valve shaft 17. Then, the second protrusion 20 of the valve shaft 17 is inserted into the lower engagement recess 27 of the second valve plate 22 (see Fig. 10), and the fourth protrusions 54 provided on the lower parts of the two support bases 51 are inserted into the lower engagement recess 29 of the second valve plate 22 (see Fig. 11). Then, the inner surface 22b of the second valve plate 22 is brought into contact with the second side surface portion 17b of the valve shaft 17, and the positioning pin 74b is inserted into the positioning groove 22d provided in the inner surface 22b of the second valve plate 22 (see Fig. 9).

[0095] 10 and 15, the second clamp piece 40 is rotated around the axis of the second fastening bolt 71, and the second engagement protrusion 43 is inserted into the second engagement recess 45. When the second fastening bolt 71 is then rotated in the fastening direction, the second clamp piece 40 moves downward, and the second engagement protrusion 43 is inserted into the second engagement groove 45a. When the first fastening bolt 67 is further rotated in the fastening direction and tightly fastened to the valve shaft 17, the second valve plate 22 is fastened via the second clamp piece 40 to the second side surface portion 17b of the valve shaft 17 in a state of intimate contact.

[0096] 11 and 15 , when the third clamp piece 60 attached to the upper end of one of the two support bases 51 in the longitudinal direction is rotated, the fifth engagement protrusion 65 is released from engagement with the first valve plate 21, and then the third engagement protrusion 62 is inserted into the third engagement recess 64, and the fourth engagement protrusion 63 is inserted into the fourth engagement recess 66. When the third fastening bolt 72 is rotated in the fastening direction, the third clamp piece 60 moves downward, and the third engagement protrusion 62 is engaged with the third engagement groove 64a, and the fourth engagement protrusion 63 is engaged with the fourth engagement groove 66a. When the third fastening bolt 72 is tightly fastened to the third clamp piece 60, one longitudinal side of the first valve plate 21 and the second valve plate 22 are fastened to each other with the support base 51 sandwiched therebetween.

[0097] Then, by operating the other support base 51 on the other longitudinal side of the two support bases 51 in the same manner as the one support base 51 described above, the first valve plate 21 and the second valve plate 22 are connected to each other with the other longitudinal sides thereof sandwiching the support base 51. As a result, the second valve plate 22 can be attached to the valve shaft 17, as shown in FIG.

[0098] Thus, according to the second embodiment of the gate valve 10, the first valve plate 21 or the second valve plate 22 can be detachably attached to the valve shaft 17 simply by loosening the first to third fastening bolts 67, 71, 72 and rotating the first clamp piece 31, the second clamp piece 40, and the third clamp piece 60.

[0099] [Third embodiment] Next, a third embodiment of the gate valve 10 according to the present invention will be described. In the third embodiment, differences from the first and second embodiments will be mainly described, and the same parts as those in the first and second embodiments will be assigned the same reference numerals and descriptions thereof will be omitted.

[0100] The gate valve 10 in the above-described embodiment is configured to include a valve shaft 17, a first valve plate 21, a second valve plate 22, and an operating mechanism 24, but the gate valve in this embodiment further includes a valve box 11 that houses the first valve plate 21 and the second valve plate 22. In this embodiment, a case will be described in which the gate valve 10 is disposed between a first chamber 1 and a second chamber 4 that are adjacent to each other, as shown in FIG.

[0101] First, we will provide an overview of the first chamber 1 and the second chamber 4. The first chamber 1 is a transfer chamber that houses a transport device for transporting workpieces such as semiconductor substrates into and out of the second chamber 4, and the second chamber 4 is a process chamber that processes the workpieces in a vacuum atmosphere.

[0102] The first chamber 1 and the second chamber 4 are provided with a first chamber opening 2a and a second chamber opening 5a, respectively, for passing the workpieces when loading and unloading them. The first chamber opening 2a is connected to a first gate opening (first opening) 12a provided in a valve box 11 of a gate valve 10, and the second chamber opening 5a is connected to a second gate opening (first opening) provided in the gate valve 10. 2 These chamber openings 2a, 5a are connected to each other or opened and closed individually by a first valve plate 21 and a second valve plate 22 provided on the gate valve 10, thereby hermetically sealing the first chamber 1 or the second chamber 4.

[0103] The first chamber 1 and the second chamber 4 are formed in a hollow box shape and each have a first chamber wall 2 and a second chamber wall 5 extending along a front wall (side wall) 12 and a rear wall (side wall) 13 disposed on both sides of the valve box 11 in the front-to-rear direction. A first chamber opening 2a is formed in the first chamber wall 2, penetrating into the transfer space 1a of the first chamber 1, and a second chamber opening 5a is formed in the second chamber wall 5, penetrating into the processing space 4a of the second chamber 4. The first chamber opening 2a and the second chamber opening 5a are formed in similar, approximately rectangular shapes, and each extends in the left-to-right direction (longitudinal direction) perpendicular to the front-to-rear direction. Note that the first chamber opening 2a and the second chamber opening 5a may be the same shape.

[0104] As shown in Figures 16 and 17, the gate valve 10 is configured to include a hollow valve body 11 in which a first gate opening 12a and a second gate opening 13a are opened and a valve space 11a is formed inside, a first valve plate 21 and a second valve plate 22 which open and close communication between the pair of first gate opening 12a and second gate opening 13a by operation of a valve shaft 17 (i.e., these gate openings 12a, 13a are opened and closed airtightly through the valve space 11a), the valve shaft 17 connected to these valve plates 21, 22, and an operating mechanism 24 which opens and closes the first valve plate 21 and the second valve plate 22 via the valve shaft 17.

[0105] In this embodiment, an operating mechanism 24 is disposed at the bottom of the valve box 11, and a valve shaft 17 protrudes into the valve space 11a from the bottom of the valve box 11. A first gate opening 12a and a second gate opening 13a are formed in the front wall 12 and the rear wall 13, which are disposed at the front and rear of the valve box, and these gate openings 12a, 13a face each other.

[0106] The first valve plate 21 closes the second gate opening 13a by pressing the sealing member 21a of the first valve plate 21 against the valve sealing surface 13b around the second gate opening 13a in the rear wall 13, and the second valve plate 22 closes the first gate opening 12a by pressing the sealing member 22a of the second valve plate 22 against the valve sealing surface 12b around the first gate opening 12a in the front wall 12.

[0107] Two air cylinders 25 constituting the operating mechanism 24 operate to open and close the first valve plate 21 and the second valve plate 22 via the valve shaft 17. Specifically, these air cylinders 25 are configured to be switchably movable between a first closing position where the seal member 22a of the second valve plate 22 is pressed against the valve seal surface 12b around the first gate opening 12a to close the first gate opening 12a, a second closing position where the seal member 21a of the first valve plate 21 is pressed against the valve seal surface 13b around the second gate opening 13a to close the second gate opening 13a, and a retracted position where the first valve plate 21 and the second valve plate 22 are connected to each other through the first and second gate openings 12a, 13a.

[0108] The retracted position may include an intermediate position where the first valve plate 21 and the second valve plate 22 are positioned midway between the first and second gate openings 12a, 13a so that the first and second gate openings 12a, 13a are connected, and a lower position below the intermediate position, or may be a lower position where the first valve plate 21 moves from the first closing position to the lower position or the second valve plate 22 moves to the second closing position, and the first valve plate 21 moves from the first closing position to the lower position or the second valve plate 22 can move directly from the second closing position to the lower position.

[0109] The valve box 11 comprises a front wall 12 and a rear wall 13 arranged opposite each other with a gap in the front-to-rear direction, a pair of side walls 14 connecting both left-to-right ends of the front wall 12 and the rear wall 13, and a top wall 15 covering an upper opening 15a opening at the top of these walls. The first gate opening 12a and the second gate opening 13a provided in the front wall 12 and the rear wall 13 have a rectangular shape extending in the left-to-right direction, and the first gate opening 12a and the first chamber opening 2a of the first chamber 1 have similar shapes and communicate with each other. Note that the first gate opening 12a and the second gate opening 13a may have the same shape.

[0110] The top wall 15 is detachably attached to the upper ends of the front wall 12, the rear wall 13, and the pair of side walls 14, 14. In this embodiment, the top wall 15 is detachably attached to these walls with fastening members such as bolts 16.

[0111] In the gate valve 10 of this embodiment, when removing the first valve plate 21 or the second valve plate 22 from the valve shaft 17, the top wall 15 is removed from the valve box 11 to expose the first valve plate 21 or the second valve plate 22 through the upper opening 15a, as shown in Fig. 16. When removing the first valve plate 21 from the valve shaft 17, the second valve plate 22 is moved to the second closing position, and then the same removal procedure as in the first and second embodiments is performed to remove the first valve plate 21 from the valve shaft 17. When removing the second valve plate 22 from the valve shaft 17, the first valve plate 21 is moved to the first closing position, and then the same removal procedure as in the first and second embodiments is performed to remove the second valve plate 22 from the valve shaft 17.

[0112] On the other hand, when attaching the removed first valve plate 21 to the valve shaft 17, with the second valve plate 22 moved to the second closing position, the first valve plate 21 to be attached is inserted into the valve space 11a of the valve box 11 through the upper opening 15a of the valve box 11 that is opened by removing the top wall 15. Then, the same attachment work as in the first and second embodiments is performed to attach the first valve plate 21 to the valve shaft 17. Also, when attaching the removed second valve plate 22 to the valve shaft 17, with the first valve plate 21 moved to the first closing position, the second valve plate 22 to be attached is inserted into the valve space 11a of the valve box 11 through the upper opening 15a of the valve box 11 that is opened by removing the top wall 15. Then, the same attachment work as in the first and second embodiments is performed to attach the second valve plate 22 to the valve shaft 17.

[0113] In this way, with the gate valve 10 of this embodiment, by removing the top wall 15 from the valve box 11, the first valve plate 21 or the second valve plate 22 can be easily removed and installed through the opened upper opening 15a. Furthermore, the first to third fastening bolts 67, 71, 72 inserted into the first to third clamp pieces 31, 40, 60 are configured to be retained, so that these fastening bolts 67, 71, 72 can be prevented from falling into the valve box 11 when replacing the first valve plate 21 or the second valve plate 22. This improves the ease of maintenance of the valve plates 21, 22.

[0114] In the above-described embodiment, the first clamp piece 31, the second clamp piece 40, and the third clamp piece 60 of the fastening mechanism 30 and the support mechanism 50 each have a convex engaging protrusion 34, 43, 62, 63, and the engaging recesses 36, 45, 64, 66 that engage with these protrusions are concave. However, this is not limited to this. The first clamp piece 31, the second clamp piece 40, and the third clamp piece 60 may each have a concave engaging recess (not shown), and the first and second valve plates 21, 22 may be provided with convex engaging protrusions (not shown) that engage with these recesses. Furthermore, in the above-described embodiment, a set of support mechanisms 50 is disposed between the opposing first valve plate 21 and second valve plate 22 at both longitudinal ends of these valve plates 21, 22. However, this is not limited to this. One or more other sets of support mechanisms 50 may be disposed between these valve plates 21, 22, longitudinally inward of the set of support mechanisms 50. [Explanation of symbols]

[0115] 10 Gate valve 11 Valve box 11a Valve space 12 Front wall (side wall) 12a First gate opening (first opening) 13 Rear wall (side wall) 13a Second gate opening (second opening) 14 Side wall 15 Ceiling wall 17 Valve shaft 17a 1st side part 17b Second side part 17c Shaft end face 19 First protrusion (engaged portion, convex portion) 20 Second protrusion (engaged portion, convex portion) 21 1st valve plate 21b, 22b inner surface 21e, 22e Seal surface (outer surface) 22 2nd valve plate 24 Operating mechanism 26, 27 Lower engagement recess (engagement portion, recess) 28, 29 Lower engagement recess (base end engagement, recess) 30 Fastening mechanism 31 First clamp piece 32 First clamp body 33 Main body locking claw (first locking claw) 34 1st engagement convex part 36 First engagement recess 36c First extension recess 40 Second clamp piece 41 Second clamp body 42 Main body locking claw (second locking claw) 43 Second engagement protrusion 45 Second engagement recess 45c Second extension recess 47 Gap 50 Support Organization 51 Support stand 51c Support end face 53 Third protrusion (base end side engagement protrusion, protrusion) 54 Fourth protrusion (base end side engagement protrusion, protrusion) 60 Third clamp piece 61 Third clamp body 61b protrusion Piece Department 62 Third engagement protrusion 63 4th engagement convex part 64 Third engagement recess 64d Third extension recess 65 5th engagement convex part 66 Fourth engagement recess 67 First fastening bolt (first fastening member) 68a Male thread 68b Thin diameter section (non-threaded section) 70 Female thread (screw hole) 71 Second fastening bolt (second fastening member) 72 Third fastening bolt (third fastening member) L axis P1 Engagement position P2 Attachment / detachment position

Claims

1. a gate valve disposed between a first chamber and a second chamber adjacent to each other, for connecting a first opening leading to the first chamber and a second opening leading to the second chamber to each other and for individually opening and closing the first opening and the second opening, The gate valve is a valve shaft extending axially from a base end side to a tip end side; a first valve plate and a second valve plate attached to a tip end portion of the valve shaft in the axial direction, formed to be elongated in a direction perpendicular to the axis, each having an inner surface facing the valve shaft and an outer surface facing away from the inner surface and fitted with an annular seal member; an operating mechanism that operates the valve shaft to move the first and second valve plates to a retracted position that allows the first opening and the second opening to communicate with each other, a first closing position that closes the first opening with an outer surface of the first valve plate, and a second closing position that closes the second opening with an outer surface of the second valve plate, Furthermore, the gate valve a fastening mechanism that detachably attaches the first and second valve plates to the tip portion of the valve shaft by detachably fastening the first and second valve plates and the valve shaft to each other in a state in which the inner surfaces of the first valve plate and the second valve plate abut against the tip portion of the valve shaft and sandwich the tip portion of the valve shaft between the valve plates; and and at least one pair of support mechanisms for releasably fastening the first and second valve plates to each other at least at both ends of the first and second valve plates in the longitudinal direction. A gate valve characterized by:

2. The fastening mechanism includes: a first clamp piece disposed between the valve shaft and the first valve plate from a tip end side of the valve shaft in the axial direction, the first clamp piece being detachably engaged with the first valve plate and detachably fixed to the valve shaft; a second clamp piece disposed between the valve shaft and the second valve plate from a tip end side of the valve shaft in the axial direction, and releasably engaged with the second valve plate and releasably fixed to the valve shaft; a first fastening member and a second fastening member that detachably fasten the first clamp piece and the second clamp piece to the tip end portion of the valve shaft, the base end portions of the first and second valve plates in the axial direction are engaged with the tip portion of the valve shaft from the tip side of the valve shaft in a concave-convex manner; When the first and second clamp pieces are fixed to the valve shaft by the first and second fastening members, the engagement between the first and second clamp pieces and the first and second valve plates presses the tip ends of the first and second valve plates toward the inner surfaces thereof, respectively, and the proximal end ends of the first and second valve plates are pressed toward the inner surfaces thereof due to the concave-convex engagement between the proximal end ends of the valve plates and the tip end of the valve shaft, respectively; As a result, the first and second valve plates are fastened to the tip end of the valve shaft.

2. The gate valve according to claim 1.

3. the recess-projection engagement between the base end side ends of the pair of valve plates and the tip end portion of the valve shaft is formed by engagement between an engaging portion provided at each of the base end portions of the pair of valve plates and a pair of engaged portions provided at the tip end portion of the valve shaft, the engaging portion being either a recess or a convex portion engaged therewith, and the engaged portion being the other of the recess or the convex portion, The first valve plate and the second valve plate are formed with a first engagement recess and a second engagement recess at a longitudinal center of the inner surface thereof, the first engagement recess and the second engagement recess opening toward a tip end side in the axial direction, The first clamp piece and the second clamp piece are formed with a first engaging protrusion and a second engaging protrusion that are engaged with the first and second engaging recesses, by fixing the first clamp piece to the valve shaft with the first fastening member in a state in which the first engaging protrusion is engaged with the first engaging recess and the engaging portion and the engaged portion formed on the first valve plate and the valve shaft are engaged with each other, a pressing force of the first engaging protrusion toward the first engaging recess toward the inner surface of the first valve plate and a pressing force of the engaging portion toward the engaged portion toward the inner surface of the first valve plate are applied, and the first valve plate is fastened to the valve shaft, the second clamp piece is fixed to the valve shaft with the second fastening member in a state in which the second engaging protrusion is engaged with the second engaging recess and the engaging portion and the engaged portion formed on the second valve plate and the valve shaft are engaged with each other, whereby the second engaging protrusion applies a pressing force to the second engaging recess in the direction of the inner surface of the second valve plate and the engaging portion applies a pressing force to the engaged portion in the direction of the inner surface of the second valve plate, thereby fastening the second valve plate to the valve shaft.

3. The gate valve according to claim 2.

4. the first and second fastening members are a first fastening bolt and a second fastening bolt, The valve shaft has a tip end surface in the axial direction having threaded holes into which the fastening bolts are screwed. The first and second clamp pieces have through holes through which the first and second fastening bolts are inserted, The first clamp piece is fixed to the valve shaft by inserting the first fastening bolt into the through hole of the first clamp piece and screwing it into the threaded hole of the valve shaft, and the second clamp piece is fixed to the valve shaft by inserting the second fastening bolt into the through hole of the second clamp piece and screwing it into the threaded hole of the valve shaft.

4. The gate valve according to claim 3.

5. The first clamp piece has the first engaging protrusion on one end side thereof sandwiching the through hole, and has a first locking claw on the other end side thereof, When the first clamp piece is fixed by the first fastening bolt, the first locking claw is locked to the valve shaft toward the first engaging protrusion, the second clamp piece has the second engaging protrusion on one end side thereof sandwiching the through hole, and has a second locking claw on the other end side thereof; When the second clamp piece is fixed by the second fastening bolt, the second locking claw is locked to the valve shaft toward the second engaging protrusion.

5. The gate valve according to claim 4.

6. the first clamp piece is rotatable about the axis of the first fastening bolt between an engagement position in which the first engagement protrusion is engaged with the first engagement recess and a detachment position in which the first engagement protrusion is detached from the first engagement recess when the first fastening bolt is loosened, the first clamp piece is accommodated in a gap between an inner surface of the first valve plate and an inner surface of the second valve plate when the first clamp piece is rotated from the engagement position to the detachment position, the second clamp piece is rotatable about the axis of the second fastening bolt between an engagement position in which the second engagement protrusion is engaged with the second engagement recess and a detachment position in which the second engagement protrusion is detached from the second engagement recess when the second fastening bolt is loosened, the second clamp piece is accommodated in a gap between an inner surface of the first valve plate and an inner surface of the second valve plate when the second clamp piece is rotated from the engagement position to the detachment position.

5. The gate valve according to claim 4.

7. The first and second fastening bolts each have a shaft portion extending in an axial direction, a head portion provided at a tip end portion of the shaft portion in the axial direction, and a male thread portion formed on an outer peripheral surface of the shaft portion, The through holes formed in the first and second clamp pieces have inner surfaces formed with female threads that can be threadedly engaged with the male threads, The shaft portion further has a small diameter portion on the head side of the male thread portion, the small diameter portion having an outer diameter smaller than the inner diameter of the female thread portion, The thin-diameter portion is inserted into the through-hole, When the first and second fastening bolts are loosened, the head side ends of the male thread portions come into contact with the female thread portions of the first and second clamp pieces.

7. The gate valve according to claim 6.

8. The support mechanism includes: at least one pair of support bases sandwiched between the first valve plate and the second valve plate at least at both longitudinal ends of the first valve plate and the second valve plate; a third clamp piece disposed from a tip end side of each of the pair of support bases in the axial direction so as to straddle the first valve plate and the second valve plate, and releasably engaged with the first and second valve plates and removably fixed to each of the support bases; a third fastening member that detachably fastens the third clamp piece to the axial tip of the support base, The base end portions of the first and second valve plates in the axial direction are engaged with the support base from the tip side of the support base in a concave-convex manner, the third clamp piece is engaged with the first and second valve plates, and the proximal end portions of the pair of valve plates and the support base are engaged in a concave-convex manner, and the third clamp piece is fixed to the support base with the third fastening member, whereby the distal end portions and proximal end portions of the first and second valve plates are pressed toward the inner surfaces thereof, As a result, the first and second valve plates and the support base are fastened to each other.

2. The gate valve according to claim 1.

9. the concave-convex engagement between the base end portions of the pair of valve plates and the support base is formed by engagement between a pair of base end engaging recesses provided at the base end portions of the pair of valve plates and a pair of base end engaging protrusions provided at the support base, The first valve plate and the second valve plate are formed with third and fourth engagement recesses at least at both longitudinal ends of the inner surfaces thereof, the third and fourth engagement recesses opening toward the tip ends in the axial direction, The third clamp piece is formed with a third engaging protrusion and a fourth engaging protrusion that are engaged with the third engaging recess and the fourth engaging recess, by fixing the third clamp piece to the support base with the third fastening member while engaging the third engaging convex portion and the fourth engaging convex portion with the third engaging recess and the fourth engaging recess, and engaging the base-side engaging recess and the base-side engaging convex portion formed on the first and second valve plates and the support base, the third engaging convex portion applies a pressing force toward the third engaging recess and the fourth engaging convex portion applies a pressing force toward the inner surface of the first valve plate to the third engaging recess and the fourth engaging convex portion applies a pressing force toward the inner surface of the first valve plate to the base-side engaging convex portion, and the base-side engaging recess applies a pressing force toward the base-side engaging convex portion to the inner surface of the first valve plate, thereby fastening the first and second valve plates and the support base to each other.

9. The gate valve according to claim 8.

10. the third fastening member is a third fastening bolt, A threaded hole into which the third fastening bolt is screwed is formed on the axial tip surface of the support base, The third clamp piece has a through hole through which the third fastening bolt is inserted, The third clamp piece is fixed to the support base by inserting the third fastening bolt into the through hole of the third clamp piece and screwing it into the screw hole of the support base.

10. The gate valve according to claim 9.

11. the third engagement recess, the fourth engagement recess, and the base-end engagement recess extend in the longitudinal direction of the valve plate, and their outer ends open outward in the longitudinal direction, the support mechanism is detachable from the first and second valve plates by loosening the third fastening bolt, whereby the third engaging protrusion and the fourth engaging protrusion of the third clamp piece are engaged with the third engaging recess and the fourth engaging recess of the first and second valve plates, and the base-end engaging recess and the base-end engaging protrusion are engaged with each other, causing the third engaging protrusion and the fourth engaging protrusion to slide along the third engaging recess and the fourth engaging recess, and causing the base-end engaging recess to slide along the base-end engaging protrusion.

11. The gate valve according to claim 10.

12. the third clamp piece is rotatable about the axis of the third fastening bolt from a state in which the third engagement protrusion is engaged with the third engagement recess and the fourth engagement protrusion is engaged with the fourth engagement recess by loosening the third fastening bolt, The third clamp piece further includes a protruding piece portion that protrudes radially from the third fastening bolt, The protruding piece has a fifth engaging protrusion formed at a tip end thereof in a protruding direction, the fifth engaging protrusion being engageable with the third engaging recess and the fourth engaging recess; the third engaging protrusion and the fourth engaging protrusion are disposed on both radial sides of the third fastening bolt, the fifth engaging protrusion is disposed at a position that forms a right angle around the axis of the third fastening bolt with respect to the third engaging protrusion and the fourth engaging protrusion, The third clamp piece is configured such that, with the third engaging protrusion and the fourth engaging protrusion engaged with the third engaging recess and the fourth engaging recess, the third fastening bolt is loosened to rotate the third clamp piece around the axis of the third fastening bolt, thereby engaging the fifth engaging protrusion with the third engaging recess or the fourth engaging recess to lock either the first valve plate or the second valve plate, and at the same time releasing the other of the valve plates from engagement with the third clamp piece.

11. The gate valve according to claim 10.

13. The third fastening bolt has a shaft portion extending in the axial direction, a head portion provided at the axial tip portion of the shaft portion, and a male thread portion formed on the outer peripheral surface of the shaft portion, a female screw portion that can be threadedly engaged with the male screw portion is formed on the inner surface of the through hole that is opened in the third clamp piece; The shaft portion further has a small diameter portion on the head side of the male thread portion, the small diameter portion having an outer diameter smaller than the inner diameter of the female thread portion, The thin-diameter portion is inserted into the through-hole, When the third fastening bolt is loosened, the end of the male thread portion on the head side comes into contact with the third clamp piece.

13. The gate valve according to claim 12.

14. The gate valve further accommodates the first valve plate and the second valve plate. A valve body is provided. The valve body includes a side wall surrounding the first and second valve plates around the axis; a top wall detachably attached to the tip end of the side wall in the axial direction; It has The side wall has the first opening and the second opening facing each other. It has been opened, 14. The gate valve according to claim 1.

Images