KR101048971B1 - Shot blasting device - Google Patents

Abstract

A shot blasting apparatus for shot blasting a workpiece is disclosed. The shot blasting apparatus includes a rail (2) mounted on an upper portion thereof and extending in a horizontal direction, one or two hoists (3) movable along the rail, and two inverters (4). . Each inverter 4 comprises a chain sling 1 for suspending and supporting one or the other end of one workpiece W and a feeder for supplying the chain sling 1. The enclosure B in the shot blasting apparatus has an inlet on one side and defines the projection chamber 5 therein. The long opening 51 is provided in the upper surface of the enclosure B. As shown in FIG. The projection chamber 5 is movable along the direction in which the workpiece W supported by the chain sling 1 extends the rail 2 by running of the hoist 3, while the workpiece W moves on the rail 2. Has a volume rotatable about an axis of rotation parallel to the direction in which it is extended. A sealing mechanism 6 is provided on the upper surface of the enclosure B to prevent the projection material from dispersing from the opening 51 by closing the opening 51 through which the chain sling 1 is inserted.

Description

Shot blasting apparatus {SHOT-BLASTING MACHINE}

The present invention relates to a shot blasting device, in particular a shot blasting device suitable for shot blasting treatment of large metal products.

As a conventional apparatus for short blasting a large metal product as a workpiece, a short blasting apparatus having a rotary table is disclosed in Japanese Patent Laid-Open No. 9-47966, assigned to the assignee of the present application. In the apparatus, the workpiece is placed on the rotary table, and shot blasted while rotating the workpiece.

However, when a large metal product is shot blasted, in the rotary table type shot blasting apparatus, since the workpiece is disposed on the rotary table, the rotary table causes blind spots in the projection to the workpiece ( For example, the bottom surface of the workpiece, or the part of the workpiece in the shadow of the turntable itself. Therefore, the same cannot be projected on the processing surface of the workpiece. In particular, the blind spot of the workpiece increases when the workpiece has a complicated outer shape or a hollow casting using a core. Thus, the area where projection is insufficient also increases.

In order to solve the problem of the rotary table type shot blasting apparatus, a shot blasting apparatus equipped with a hoist is also known as disclosed in Japanese Patent Laid-Open No. 9-234671. In the hoist type shot blasting apparatus, the workpiece in suspension can be tilted while the shot blasting is performed by suspending the workpiece into a plurality of chains and adjusting the length of the chain. For example, a long workpiece may be suspended by a pair of chains at both ends of its longitudinal axis so that the suspended workpiece may be tilted by adjusting the length of each chain. Therefore, the hoist type shot blasting apparatus has fewer blind spots than the table type shot blasting apparatus and is excellent in terms of shot blasting quality.

However, in the hoist type apparatus of Japanese Patent Laid-Open No. 9-234671, although the workpiece can be tilted in a suspended state, the suspended workpiece can be rotated completely, for example, around its longitudinal direction. There is no.

Therefore, in the case where a pocket such as a predetermined recess or recess is formed in the processing surface of the workpiece, the projection material accumulates in the pocket and the shot surface cannot be completely blasted. In addition, when the workpiece is long, it is necessary to make the height, width, and depth of the projection chamber longer than the long side of the workpiece in order to increase the degree of freedom of tilt movement. In addition, when the workpiece is placed vertically long, the state itself tends to destabilize the workpiece. When the workpiece is positioned in a horizontally long state, the distance between the pair of chains supporting both ends of the workpiece is widened, and the inclination angle of the pair of chains is also increased. As a result, a large load is applied to the sieve unit provided on the ceiling of the projection chamber in order to guide the chain smoothly to the drive wheel. Thereby, there is a fear that the sieve unit is worn, the projection material is dispersed from the projection chamber, the working environment is deteriorated, or each chain is initially worn and cut. In addition, (when the workpiece is long) conventionally, in consideration of the balance of the workpiece, the workpiece is suspended at both ends in the longitudinal direction during the shot blast treatment. In this case, in order to process the whole circumferential surface of a workpiece | work conventionally, the both ends of the longitudinal direction of a long workpiece | work are moved up and down. For example, if the long workpiece is 5 m in length and 0.2 m in diameter, a projection chamber of 5 m x 5 m in length and 0.2 m in width in the vertical direction is required in order to move both ends of the workpiece up and down. Therefore, since the volume of the projection chamber is relatively large, it is not preferable from the viewpoint of saving space.

Accordingly, one object of the present invention is to provide a shot blasting apparatus which improves the polishing quality, reduces the volume of the projection chamber, prevents scattering of the projection material, and is particularly suitable for shot blast treatment of large metal products.

A shot blasting apparatus for short blasting the workpiece of the present invention comprises: a rail mounted on an upper portion of the shot blasting apparatus and extending in a horizontal direction; Lifting means movable along the rail and movable in a vertical direction; Two inverters suspended from the elevating means, each having an endless member suspending and supporting one or the other end of one workpiece and a feeder for supplying the endless member, the workpiece being suspended at both ends thereof. Two inverters cooperating in a suspension state supported by the endless member to rotate in a reverse rotation about an axis parallel to the extending direction of the rail; An enclosure having an inlet on one side and defining a projection chamber therein, the upper surface of the enclosure having a direction extending from the inlet to form a passageway for the endless member on which a workpiece is suspended. An elongated opening is provided, wherein the workpiece supported by the endless member can move along the extension direction of the rail by running the elevating means, while the workpiece is a rotation axis parallel to the extension direction of the rail. An enclosure having a volume of a projection chamber that can rotate relative to the projection chamber; A projector mounted in the projection room, the projector projecting a projection material; A seal mechanism mounted to an upper surface of the enclosure and closing the opening through which the endless member is inserted, in order to prevent scattering of the projection material; And projection material circulation means for recovering the projected projection material and resupplying the projection material.

Preferably, the seal mechanism has a seal member positioned at a predetermined position where the workpiece is shot blasted in the projection chamber, and closing the area where the endless member is not disposed in the opening while the lifting means is stopped. Include.

In one embodiment of the present invention, the seal member is located at a predetermined position where the workpiece is shot blasted in the projection chamber, and in the state in which the elevating means is stopped, the seal members are included in the two inverters on the enclosure. A pair of first outer seals disposed at positions corresponding to the front position of the preceding inverter and the rear position of the subsequent inverter, the pair of first outer seals slidably arranged to slide in a direction orthogonal to the extension direction; And a second inner seal disposed at a position corresponding to a center point between two inverters on the enclosure and slidable in a direction orthogonal to the extending direction. In this case, the seal mechanism further includes a pair of third seals disposed at the position corresponding to the positions of the two stationary inverters stopped on the enclosure, the third seal being the It is slidably arranged along the direction orthogonal to an extension direction, and each of the 3rd seals is provided with the several notch or clearance which the said endless member is inserted in the lateral direction. In one embodiment of the present invention, the third seal is further slidably arranged along the same direction as the extending direction.

In one embodiment of the present invention, the elevating means is one or two hoists suitable for vertically moving the two inverters.

The above and other objects and advantages of the present invention will become apparent from the following detailed description with reference to the accompanying drawings.

1 is a diagram schematically showing a shot blasting apparatus according to an embodiment of the present invention.

FIG. 2 is a front view of the shot blasting apparatus of FIG. 1 viewed from the entrance side thereof. FIG.

FIG. 3 is a plan view of the projection chamber of the shot blasting apparatus of FIG. 1, illustrating a seal structure in an open state.

4 is a plan view similar to FIG. 3, with the outer seal and the inner seal closing the opening, and the seal for the endless member is shown without closing the opening.

FIG. 5 is a plan view similar to FIG. 4, but with the seal opening for the endless member shown in a closed state. FIG.

FIG. 6 is a plan view similar to FIG. 3, but showing a state in which the open endless member seal is moved in the horizontal running direction of the endless member.

In the upper part of the shot blasting apparatus which concerns on 1st Embodiment of this invention shown in FIGS. 1-3, the horizontal rail 2 which can support the load of the suspended workpiece W is provided. The rail 2 is above the enclosure B defining the projection chamber 5 therein from above the work area S for winding and unwinding the workpiece W with a chain sling 1. Extends.

The rail 2 is provided with two hoist 3 (elevation means) which can move along the said rail 2, and is movable, for example by the wire 31 vertically, respectively. The inverter 4 is suspended in the wire 31 of each hoist 3. The inverter 4 comprises a chain sling 1 for forming an endless member by connecting both ends of the chain, and a supply mechanism for supplying the chain sling 31. The chain sling 1 has a length which can wind at least a part of the circumferential surface of the workpiece W. As shown in FIG. The two inverters 4 cooperate with each other so that one work piece W is supported by the chain sling 1 at both ends to reversely rotate, forward rotate and tilt. At one end of the enclosure B facing the work area S, an entrance for accessing the projection chamber 5 defined inside the enclosure B is provided. In addition, an elongate opening 51 (FIGS. 2 and 3) is formed in the ceiling 52 that defines the upper surface of the projection chamber 5. The long opening 51 extends from the inlet along the direction in which the rail 2 extends to form a passage for the chain sling 1 in which the workpiece W is suspended. The volume of the projection chamber 5 can move along the direction in which the workpiece W supported by the chain sling 1 extends along the rail 2 by running of the hoist 3, while the workpiece W The rail 2 is selected to be able to rotate about an axis of rotation substantially parallel to the direction in which it extends.

In the projection chamber 5, a plurality of projectors 7 for accelerating and projecting the projection material are provided. Each projector 7 may use a conventionally known device. Although the centrifugal projector was used in this embodiment, it is not limited to this. For example, when only a limited portion of the entire circumferential surface of a large workpiece is processed, an air projector for accelerating and projecting the projection material with air may be used.

In the projection chamber 5, projection material circulation means 8 for recovering the projected projection material and resupplying it to the projector is also provided. 1 and 2, the projection material circulation means 8 is disposed under the projection chamber 5, and the oscillate conveyor 81 conveys the projection material dropped to the lower part of the projection chamber 5 in the horizontal direction. an oscillating conveyor and a bucket elevator (82) disposed near a leading end of the oscillating conveyor (81) to convey upwardly the projection material conveyed by the conveyor (81). Doing. At the upper end of the bucket elevator 82, a discharge port 83 for discharging the projection material is provided. In the vicinity of the discharge port 83, a horizontal screw conveyor 84 is arranged to accommodate the projected material emitted. The horizontal screw conveyor 84 is provided with a plurality of projection material outlets 84a. A hopper 85 for storing the projection material is arranged below the projection material outlet 84a of the horizontal screw conveyor 84, and its bottom portion communicates with the first pipe 86. The first pipe 86 is provided with a gate 87 that opens and closes the first pipe 86 so as to control the amount of projection material flowing through the pipe 86. Next, the bottom of the gate 87 is connected to the second pipe 88 in communication with the inlet of each projector for supplying the projection material.

The ceiling 52 of the projection chamber 5 is equipped with a seal mechanism 6 for sealing the projection chamber 5 in order to prevent the projected projection material from being dispersed from the opening 51. The seal mechanism 6 is formed with a plurality of cutouts or gaps through which the chain sling 1 can be inserted in the lateral direction, without interfering with the movement or rotation of the chain sling 1 inserted into the seal mechanism. The projection material is configured to prevent scattering of the projection material or leakage of dust from the opening 51 of the projection chamber 5. The seal mechanism 6 may be, for example, a pair of single layer rubber sheets or a pair of multilayer rubber sheets having a plurality of cutouts through which the chain sling 1 disposed in the opening 51 can be inserted through in the lateral direction. It may be composed of a pair of elastic bodies, but is not limited thereto. These elastic bodies are coupled to each other on opposite sides of the movement path H (see FIG. 3) of the chain sling 1 in the horizontal direction along the direction in which the rail 2 extends. The movement path H corresponds to the movement trajectory of the hoist 3 (not shown in FIG. 3). Alternatively, each elastic body may be, for example, a brush shape formed of a bundled wire made of a resin or a metal, a resin plate, a sponge, or a cloth brush. In the gap between the gears of the brush, a chain sling 1 disposed in the opening 51 is received in the lateral direction.

However, some areas of the opening 51 in which the chain sling 1 is not disposed during the shot blasting process can be simply closed without considering the existence of each chain sling 1. Therefore, it is preferable that the part of the sealing mechanism 6 which seals such an area is comprised from a rigid material, for example, steel plate, in order to improve the wear resistance and the leakage prevention performance of the sealing mechanism 6. The area of the opening 51, which can be simply closed without considering the presence of the chain sling 1 during the shot blasting, is the area of the front of the preceding inverter 4 of the two inverters 4, which follows. It is the region behind the inverter 4 and the area between the two inverters 4. The state in which the hoist 3 stops by placing the workpiece W at a predetermined position to be shot blasted in the projection chamber 5 will be described. The sealing mechanism which concerns on embodiment of FIG. 2 and FIG. 3 contains a pair of 1st outer side seal 61 and the 2nd inner side seal 62 which consist of steel plates, respectively.

When the hoist 3 locates the workpiece W at a predetermined position to be shot blasted in the projection chamber 5 and stops, the pair of first outer seals 61 is provided on the ceiling 52. It is arrange | positioned in the position corresponding to the front position of the preceding inverter 4, and the rear position of the following inverter 4 among the inverters 4 ,. A slide mechanism, for example, an air cylinder 61a, is operatively coupled to each of the first outer seals 61, and the direction V perpendicular to the movement path H is caused by the expansion and contraction of the air cylinder 61a. As a result, the first outer seal 61 may slide. When the hoist 3 locates the workpiece W at a predetermined position to be shot blasted in the projection chamber 5 and stops, the second inner seal 62 has two inverters (2) in the ceiling 52. It is arrange | positioned at the position corresponding to the center point of 4). A slide mechanism, for example, an air cylinder 62a, is operatively coupled to the second inner seal 62, and is formed in the direction V perpendicular to the movement path H by expansion and contraction of the air cylinder 62a. 2 inner seal 62 can slide. At a peripheral portion where the first seal 61 and the second seal 62 overlap, a sealing portion (not shown) for preventing the projected projection material from leaking is formed.

As the seal mechanism 6 includes a pair of the first outer seal 61 and the second inner seal 62, as described above, the first outer seal 61 and the second inner seal at the opening 51. The area between the seals 62 is configured such that the chain sling 1 can be inserted through as described above. This configuration is shown in the embodiment according to FIGS. 2 and 3 as a pair of third seals 63 through which the chain sling 1 can be inserted. Each third seal 63 is basically made of steel sheet, but includes a sealing portion 6S. The sealing portion 6S includes an elastic body such as a single layer or a multilayer rubber sheet having a plurality of cutouts in order to prevent the chain sling 1 from moving or rotating as described above. In practice, since the workpieces W of various sizes may be processed, due to the size difference of the workpieces W to be processed, the positions of the two inverters 4 during the shot blasting process, and thus the chain slings 1 The position of may be changed. Therefore, not only the direction V orthogonal to the movement path H of the chain sling 1 but the pair of 3rd seal 63 along the movement path H of the chain sling 1 (hoist It is preferable to be able to slide also in the travel direction (3). The pair of third seals 63 surrounds the projection chamber 5 at positions corresponding to the two inverters 4 with the hoist 3 placing the workpiece W at the processing point and stopping. It is attached to the ceiling 52 of the sieve B. As shown in FIG. The third seal 63 includes a slide mechanism such as the air cylinder 63a, and a general drive motor 63b for adjusting the distance between the pair of third seals 63. As shown in FIG. Therefore, the third seal 63 can slide along the direction V orthogonal to the movement path H by the expansion and contraction of the air cylinder 63a, and the movement path H and the movement of the movement path H by the drive motor 63b. Sliding can move along the same direction. Each of the third seals 63 is formed with a U-shaped cutout 63U through which the chain sling is inserted in the lateral direction. Preferably, the hoist 3 comprises a position detection sensor (not shown), each detecting the position of the corresponding chain sling 1. By slidingly moving the third seal 63 so that the position of the chain sling 1 detected by the position detection sensor is aligned with the corresponding U-shaped cutout 63U, the chain sling 1 is moved to the corresponding U-shape. The notch 63U can be inserted into the lateral direction.

In the steel plate of the third seal 63 in which the first (outer) seal 61, the second (inner) seal 62, and the chain sling 1 are inserted, the side surfaces collided by the projection material are abrasion resistant. You may install the liner which has this.

In the illustrated embodiment, two hoists 3 are used, but only one hoist may be used as long as the spacing between the two inverters 4 can be fixed or changed. In order to change the spacing between two inverters 4 with one hoist, suitable means may for example be a support frame with an air cylinder. In this case, the support frame can be suspended from the hoist so as to support the two inverters 4, so that the interval between the two inverters 4 can be changed. One or two hoists may be, but are not limited to, electric wire hoists or electric chain block hoists. As an alternative to the lifting means, a hydraulic cylinder or a servo cylinder may be used instead of the hoist.

Each of the inverters 4 is not limited to the illustrated embodiment, but may include an annular endless member and a feeder for supplying the endless member. Instead of the chain sling 1, the endless member may be connected to both ends to form an annular endless member, and may be another configuration that can be at least partially wound around the circumferential surface of the workpiece W. FIG. For example, a sling belt or annular wire may be used as the endless member.

Each slide mechanism of the seal retracts from the opening 51 while the workpiece W travels in the projection chamber 5, and adheres to the opening 51 while the workpiece W is shot blasted. . Each slide mechanism may be replaced by a door with a pivotal linkage. The drive means for driving the slide mechanism or the door may be replaced with the illustrated air cylinder, hydraulic cylinder, rotary cylinder, servo cylinder or motor. For example, the slide mechanism can be replaced by combining the rack and pinion mechanism with the motor.

The illustrated projection material circulation means 8 includes an oscillate conveyor 81, a bucket elevator 82, a screw conveyor 84, but the internal volume of the projection chamber 5 or the layout of the factory to be installed or all of them. Based on this, the projection material may be replaced with another configuration capable of transporting and separating from the molding sand, and removing any dust.

In the embodiment of the present invention, the operation of the shot blasting apparatus will be described with reference to a processing example for removing the molding sand from the cast product as the workpiece W. FIG. This processing example is an example for explaining the operation of the shot blasting apparatus of the present invention and is not intended to limit the present invention.

Processing conditions

The workpiece W used was a column of a machining center for machine tools. The workpiece W was cast iron, and had a length of 4000 mm, a width of 2000 mm, and a thickness of 450 mm. The projection chamber 5 in the shot blasting apparatus was 8000 mm long, 5000 mm wide, and 6500 mm high. Eight centrifugal projectors 7 were mounted on the side of the projection chamber 5. The projection material used to perform the shot blasting treatment was a steel shot. The particle size was 2.5 mm, the projection speed was 70 m / s, and the amount of steel shot projected was 150 kg / min for each centrifugal projector 7. Two hoists (3) were used to convey the workpiece (W), each with a maximum hanging load of 12 tons, a maximum rolling-up speed of 8 m / min and a maximum traveling speed of 10 m /. min. Two inverters 4 with a maximum suspension load of 10 tons were used, each of which was a chain sling inverter (manufactured by Japan Hoist Co., Ltd.). For each inverter, the length of the chain sling was 12 m and its maximum feed rate was 4 m / min.

action

The workpiece W is wound around the chain sling 1 in the working region S and suspended. Then, the hoist 3 moves along the rail 2 so that the suspended workpiece W moves into the projection chamber 5 through the loading / unloading door mounted on the end face of the projection chamber 5. When the workpiece W reaches a predetermined position to be shot blasted, each inverter 4 supplies the chain sling 1 to rotate the workpiece W at a constant speed. At the same time, the pair of first (outer) seals 61 and the second (inner) seals 62 slide to cover the openings 51. The third seal 63 for the endless member moves along the direction of the travel path of the chain sling 1 to align the third seal 63 with the position of the chain sling 1. Next, the third seal 63 is slidably moved to the opening 51 so that the chain sling 1 is inserted into the U-shaped cutout 63U of the third seal 63 to be inserted. Thus, the opening 51 is completely shielded by the first, second and third seals. After the opening 51 is shielded, the centrifugal projector 7 is driven to project the projection material into the projection chamber 5.

During the shot blasting process, the workpiece W stops after rotating for a predetermined time. In the stationary state, a predetermined portion of the workpiece W having a complicated processing shape and having a long processing time is disposed at a position where many collisions by the projection material can occur. The workpiece | work W rotates in the opposite direction after stopping a fixed time. During the shot blasting process, the workpiece W repeats the rotating step, the stopping step and the reverse rotating step in this manner. When the workpiece W has a shape in which the projection material may accumulate in the pocket part or pocket parts, the stop step may be replaced by a deceleration forward rotation step or a deceleration reverse rotation step.

In this embodiment, the projection time was 15 minutes in total. After the completion of the projection process, the workpiece W is rotated for a predetermined time to drop off some of the projection material remaining on the workpiece W after the collision. Subsequently, each seal 61, 62, and 63 closed to shield the opening 51 is slidably moved in the direction of opening the opening 51. Then, the hoist 3 moves along the rail 2, and the workpiece | work W reaches the working area S. FIG. Then, the workpiece W is removed from the chain sling 1 to complete the operation. It was observed that the workpiece W which had been shot blasted in the above-described manner was uniformly shot blasted with excellent quality without defects.

According to the shot blasting apparatus of the present invention, the chain sling 1 of the inverter 4 is wound around the workpiece W, and the workpiece W is rotated about its horizontal axis in the suspended state by driving the inverter 4. Let's do it. In this way, the pocket portion or pocket portions of the workpiece W can be lowered to remove some remaining projection material, thereby exposing the inside of the pocket portion to be treated. By rotating the suspended workpiece W, the entire circumferential surface thereof can be processed, so that any remaining projection material in the pocket portion or pocket portions can be dropped off appropriately. Therefore, even if the pocket portion is present at any position of the circumferential surface of the workpiece W, it is possible to prevent accumulation of any undesirable projection material in the pocket portion or pocket portions of the workpiece. Accordingly, the surface to be shot blasted of the workpiece can be regularly exposed to uniformly treat with improved processing quality. In addition, the seal mechanism 6 can prevent undesirable scattering of the projection material. Moreover, since the workpiece | work W can be supported by the chain sling 1 in the stable state, the fall accident of the workpiece | work W can also be prevented.

The movement of the workpiece | work W moves along the extension direction of the rail 2, and rotates about the horizontal axis in the state suspended and supported by the endless member 1. Therefore, when the workpiece | work W is long, since the shot blasting apparatus of this invention aligns the longitudinal axis of the workpiece | work W with the extension direction of the rail 2, it is necessary to make the volume of the projection chamber 5 excessively large. none. For the purpose of saving space, the volume of the projection chamber 5 can be made small. For example, when a long workpiece of 5 m in length x 0.2 m in diameter is processed, a conventional shot blasting apparatus required a projection chamber of 5 m in length, 5 m in length, and 0.2 m in width for the long workpiece W. . When the same long workpiece is treated with the shot blasting apparatus of the present invention, since the long workpiece is rotated about its longitudinal axis, the volume of the projection chamber 5 only needs 0.2 m in height x 5 m in length x 0.2 m in width. .

Suitable applications for the shot blasting apparatus of the present invention include upper and lower mold holders of press dies, lathe beds for machine tools, columns of machining centers, frames of sheet metal machines, suction casings for industrial machines, gear cases of gear reducers, nominal It may also be a short blasting process for removing casting sand from large castings, for example, castings weighing more than 1 ton, such as cast iron pipes with a diameter of 500 mm or more, spiral casings for compressors, and discharge elbows integrally molded with housings equipped with reducers. It doesn't happen. In addition, the shot blasting apparatus of the present invention is used for large-scale welded structures of bridges, shipbuilding, and steel towers, for example, the removal of scale of items such as frame structures in which parts are welded to a predetermined shape, surface preparation before coating treatment, Although it is applicable to the shot blasting process for the purpose of surface roughness etc. for improving a friction characteristic, it is not limited to this.

While specific embodiments and alternative embodiments thereof have been described above with specific dimensions, these embodiments and dimensions are for illustrative purposes and are not intended to limit the invention. Those skilled in the art will clearly appreciate that various modifications and changes can be made to the above-described embodiments and dimensions without departing from the spirit of the invention as defined in the appended claims.

Claims (6)

As an apparatus for short blasting a workpiece, A rail disposed above the shot blasting apparatus and extending in a horizontal direction; Elevating means for traveling along the rail and capable of elevating; An annular endless member which is suspended from the lifting means, each of which is at least partially wound around one end or the other end of one workpiece to suspend and hold the workpiece; Having two mechanisms for discharging the endless member, the two inverters cooperating to reversibly rotate the suspended workpiece held by the endless member about an axis parallel to the extending direction of the rail; An enclosure having an inlet on one side and defining a projection chamber therein, the upper surface of the enclosure having a narrow, extending along the extending direction from the inlet to form a passage of the endless member holding the workpiece. An elongated opening is formed, and in the projection chamber, a workpiece held in an endless member through which the opening is inserted can move in an extension direction of the rail by traveling of the elevating means, and a rotation axis parallel to the extension direction. With the enclosure having a volume rotatable around A projector arranged in the projection room to project projection material; A seal mechanism provided on an upper surface of the enclosure to prevent scattering of the projected projection material from the opening by closing the opening through which the endless member is inserted; A projection material circulating means for recovering the projection material projected in the projection chamber and resupplying the projector; The seal mechanism includes a seal member for closing an area where the endless member is not present in the opening, with the lifting means positioned and stopping the workpiece in the projection position, wherein the seal member is disposed in the extending direction. The shot blasting apparatus which is slidable along an crossing direction. The method of claim 1, The seal member, On the upper surface of the enclosure, the elevating means places the workpiece at the projection position and stops, and is disposed at a position corresponding to the front position of the preceding one of the two inverters and the rear position of the subsequent one. A pair of first outer seals slidable along a direction crossing the extension direction; The shot blasting apparatus of the upper surface of the enclosure comprising a second inner seal disposed at a position corresponding to two inverters in the stationary state and slidable in a direction crossing the extension direction. The method of claim 2, The seal mechanism further includes a pair of third seals disposed at positions corresponding to two inverters in the stationary state, respectively, on an upper surface of the enclosure, wherein each third seal is in the extending direction. The shot blasting apparatus which is slidable in the direction which cross | intersects, and has a some notch or clearance which inserts the said endless member through. The method of claim 3, wherein The shot blasting apparatus of Claim 3 which is also slidable also in the direction along the said extending direction. The method of claim 1, And said elevating means is one or two hoists suitable for elevating said two inverters. delete

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