US 3872625 A
The blasting apparatus in accordance with the present invention is a pendulous blasting apparatus in which a packaged blasting unit is suspended on the wall surface of a structure to be blasted to freely move vertically and horizontally for performing the cleaning of the wall surface of the structure, with the projecting opening of the packaged blasting unit being in tight contact with a work surface.
Claims available in
Description (OCR text may contain errors)
United States Patent 1191 1111 3,872,625 Fuma et a1. 1 1Mar. 25, 1975 [541 PENDULOUS BLASTING APPARATUS 2,732,918 1/1353 g an Deknburgh 51/8 R 3,3 ,492 8/1 6 chenc 51/8 R [751 Inventors: 1 1 Fuma TOYQkaWa; 3,566,543 3/1971 FOgle 51/9 Takeda, Toyohashh both of Japan 3,691,689 9/1972 06ft... 51/8 R x 3,747,277 7/1973 Carpenter... 51/9  Assgnee Nogoya 3,788,010 1/1974 GOff 51/9 Filedl 1973 Primary Examiner-Donald G. Kelly  Appl No 427,337 Attorney, Agent, or Firm-Armstrong, Nikaido &
Wegner  Foreign Application Priority Data 57] ABSTRACT June 11, 1973 Japan 48-65625 The blasting apparatus 1n aecordance wtth the present  U.S. C1 51/9 M invention is a Pendulous blasting apparatus in which a 51 1m. 01. B246 3/06 B240 9/00 Packaged blasting unit is suspemkd on the  Field of Serch 51/9 8 9 M 9 face of a structure to be blasted to freely move verti- [14/722 Cally and horizontally for performing the cleaning of the wall surface of the structure, with the projecting  References Cited opening of the packaged blasting unit being in tight UNITED STATES PATENTS Contact with a work surface. 2,098,262 11/1937 Temple 114/222 6 Claims, 11 Drawing Figures FATENTEU 5 i975 3, 872 .62 5
sum 1 o 1 PATENTEU 515175 sum 5 pg 1 PATENTED AR 2 5 I975 sumvq PENDULOUS BLASTING APPARATUS PROBLEMS OF PRIOR ART Two types of conventional publicy known blasting apparatus for cleaning the vertical or inclined wall surface of a large structure such as side of a ship and bridge are the one in which a packaged blasting unit is mounted at the ends of retractable beams provided on a running truck and the one in which a suspended packaged blasting unit is used. In the former type of conventional blasting apparatus, there are disadvantages that high manufacturing and operating costs needed due to its bulky construction and that capacity of the apparatus is reduced when cleaning a ship side owing to the limited moving range of the truck on account of the particular size of a dock. In the latter type of conventional blasting apparatus, wherein the packaged blasting unit is suspended, although such disadvantages are eliminated, unstable contact between the packaged blasting unit and the wall surface to be blasted often causes the leakage of abrasives and the packaged blasting unit is not capable of moving smoothly laterally with respect to the work surface. Moreover in the prior art, the abrasive recovery device associated with.the packaged blasting unit utilizes such means as a bucket conveyor, combined with a screw conveyor and a chain feeder having discs and moving in a pipe. However, the packaged blasting unit provided with such an abrasive recovery device has so large a size and weight that it is not suitable to be suspended from a high place for the cleaning operation. In addition, vibrations are readily generated in the centrifugal projecting means of the packaged blasting unit due to a high rotational frequency of the projecting means and due to the fact that the rotating blades of the projecting means are supported in the manner of a cantilever. In particular, if the rotating parts of the projecting means become uneven in dimensions on account of partial wear due to colliding abrasives, abnormal vibrations are generated in the projecting means with the result that not only the function of motor is impaired but alsoa stable and smooth operation cannot be expected from the vibrating packaged blasting unit when suspended for operation.
SUMMARY OF INVENTION The present invention relates to a pendulous blasting apparatus adapted to clean efficiently the surfaces of various large structures such as side of a ship and bridge.
The object of the present invention is to provide a pendulous blasting apparatus in which a large area of work surface can be cleaned effectively by achieving a sure contact between the work surface and the sealing member of a packaged blasting unit, projected abrasives are recovered and separated from the dust resulting from cleaning operation in a very sure manner, vibrations due to high speed rotation of a projecting means are absorbed, the packaged blasting unit is, while being in tight contact with the work surface by virtue of magnetic attraction, capable of freely moving vertically and horizontally, and the packaged blasting unit is manufactured compact and light weight.
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a front view showing an embodiment of the pendulous blasting apparatus in accordance with the present invention;
FIG. 2 is a side view taken along the line II-II of FIG. 1:
FIG. 3 is a partly broken away rear view taken along the line III-III of FIG. 2:
FIG. 4 is a longitudinal sectional view taken along the line IV-IV of FIG. 3:
FIG. 5 is a longitudinal sectional view taken along the line V-V of FIG. 3:
FIG. 6 is an outline view taken along the line IlIIII of FIG. 2:
FIG. 7 is a partial longitudinal sectional view taken along the line VI-VI of FIG. 6;
FIG. 8 is a partly broken away longitudinal sectional view of a projecting means;
FIG. 9 is a central longitudinal sectional view of a travelling wheel;
FIG. 10 is a plan view of the travelling wheel illustrated in FIG. 9; and
FIG. 11 is a partly broken away enlarged view 0 of a motor attaching portion shown in FIG. 8.
DETAILED DESCRIPTION OF INVENTION Explanations will be made on the construction in accordance'with the present invention taking reference with the attached drawings.
The present invention comprises a packaged blasting unit 1 and a frame 2 on which the packaged blasting unit 1 is mounted. The packaged blasting unit 1 comprises a centrifugal projecting means 3 arranged in the central part of the packaged blasting unit 1, a conveyor casing 5 provided therein with a rotary bucket conveyor 4 for performing the supply of abrasives to the projecting means 3 and the recovery of abrasives which cleaned the work surface, an abrasive separating chamber 6 within the conveyor casing 5 for separating and removing dust from the recovered abrasives and for circulating only usable abrasives through the projecting means 3, and a blasting chamber 7 disposed adjacent to said separating chamber 6 and the front end of the conveyor casing 5. On the other hand, the frame 2 includes travelling wheels 8 movable along the work surface and having a driving means therefor, a suspending means for suspending the frame 2, and electromagnets 9 for placing the blasting chamber 7 in tight contact with the work surface. In the first place, an explanation will be given on the construction of the packaged blasting unit 1. Numeral 10 indicates an opening arranged toward the work surface W in the front central part of the blasting chamber 7. In the rear central part of the blasting chamber 7 is mounted the projecting means 3 driven by a directly connected motor 11. Said conveyor casing 5 is provided on the rear outer periphery of the blasting chamber 7. In said conveyor casing 5 are arranged a plurality of pairs ofo receiving rollers 12. A pair of said receiving rollers 12 is fixed securely to a shaft 16 rotatably supported by bearings 18 in a bearing cover 17 mounted on said conveyor casing 5. In the conveyor casing 5, the projecting passage of abrasives to be projected from the projecting means 3 is surrounded by the rotary bucket conveyor 4 comprising doughnut-shaped side wall 13a and an outer wall 15 covering the outer periphery of said rotary bucket conveyor 4. Said receiving rollers 12 rotatably support the both outer peripheral edges of the rotary bucket conveyor 4. In the central part of the whole outer periphcry of the outer wall 15 are provided gear teeth 14 which are in mesh with a pinion fixed securely to the shaft ofa variable speed motor 19 mounted on one side of the conveyor casing 5 for driving said outer wall 15. In FIG. 3, the arrow R indicates the direction of rotation of the rotary bucket conveyor 4. Bucket 13 are formed by arranging a plurality of inclined partition plates at given intervals between the side wall 13a and side plates 130 of the rotary bucket conveyor 4. Each individual bucket 13 has therein one or two rib-like weirs 13b which form dividing means. Said weir 13b prevents the overflowing of abrasives from the bucket 13 to keep as much amount of abrasives as possible in the bucket 13 when the whole rotary bucket conveyor 4 is inclined. When the rotary bucket conveyor 4 is inclined, said receiving rollers 12 are brought into contact with the sides of the gear teeth 14 to prevent the movement in axial direction of the rotary bucket conveyor 4. The separating chamber 6 disposed in the upper part of the conveyor casing 5 has, as shown in FIG. 3, an inclined plate 21 provided substantially in the central part thereof an opening 22. In the upper part on the right side of the inclined plate 21 is arranged substantially in parallel with the inclined plate 21 a shielding plate 23 having a bent portion 23a to form an abrasive recovery passage 24. An air inlet 25 having a wire gauze is provided in the outer wall of the conveyor casing 5. Likewise, similar air inlet 27 having a wire gauze is disposed in a partition plate 26 forming the blasting chamber 7. Further, an opening 28 is arranged in the upper part of the inclined plate 21. To the lower part of said opening 22 is connected a chute 29 communicating with the projecting means 3. Above the shielding plate 23 is provided the connecting opening 31 of a duct in communication with a dust collector which is not shown in the figure. The lower part of the blasting chamber 7 is formed by an inclined bottom plate 32 whose end communicates with an abrasive storage hopper 34 in the lower part of the conveyor casing 5 through an opening 33 in the partition plate 26. A shielding plate 35 having a flat portion 35a is disposed inside the conveyor casing 5 in the part toward which the lower portion of said shielding plate 23 extends. An abrasive recovery opening 36 is arranged in the part of the shielding plate 35 in the vicinity of the end of said passage 24. A dust removing chamber 37 is formed in a space between the shielding plates 23 and 35. On the periphery of the opening 10 of the blasting chamber 7 are provided double sealing members 38 made of such a material as rubber. Turning to FIGS. 8 and 11, the projecting means 3 has the driving motor 11 whose shaft 40 has rotating blades 39 connected directly thereto. The driving motor 11 and a cover 41 covering said rotating blades 39 are fixed to a common base 42. The attaching portion 43 of the motor 11 is fixed to said base 42 by bolts 45 through pairs of vibration preventing tubular rubber pieces 44 having flange portions 44a. Said base 42 is fixed to a rubber sheet 44b arranged on the partition plate 26 forming the blasting chamber 7. Numeral 46 designates a washer provided between the vibration preventing rubber piece 44 and the head of the bolt 45. Numeral 47 indicates positioning tubular seats for the motor 11 put on the outer peripheries of the bolts 45. An abrasive distributor 48 is directly fixed to the end of said motor shaft 40 using bolts and nuts (not shown). On the inner surface of the cover 41 is disposed a wear resisting protecting plate 49, the lower end of which opens in the blasting chamber 7 through an opening 50 arranged in the base 42 and the partition plate 26. Numeral 51 designates a cage for regulating the projecting direction of abrasives. Numeral 52 indicates a labyrinth sealing portion and numeral 53 designates a disc put together with the labyrinth sealing portion 52 on the motor shaft 40 for rotation therewith so that the bearings of the motor 11 may not be damaged by flying abrasives. Next, an explanation will be given on the frame 2 and the travelling wheels 8 mounted on the frame 2. As shown in FIG. 2, to the frame 2 is fixed the partition plate 26 having the conveyor casing 5 on one surface thereof and having the blasting chamber 7 on the other surface thereof. At the four corners of the frame 2 are provided brackets 54 facing forward and to the end surfaces of said brackets 54 are securely fixed bearings 55. Both ends of rotating shafts 56 are rotatably supported in the opposite upper and lower bearings 55 disposed, as described above, on the left and right vertical peripheral edges of the front surfaces of the frame 2. At the each end of each rotating shaft 56 are mounted side by side two travelling wheels 8 rotatable freely in both longitudinal and lateral directions. As shown in FIGS. 9 and 10, the travelling wheel 8 comprises a disc 57 fixed securely to said rotating shaft 56 and having at peripheral edged thereof a number of recesses 58 spaced to each other at equal intervals. In each said recess 58 is arranged rotatably a roller 59 having a shaft 60. Travelling Surface of each roller 59 is lined with rubber for preventing slipping and damage to work surface. Mounting of the roller 59 on the disc 57 is performed by putting small diameter shaft portions 62 at both ends of the shaft 60 of the roller 59 between the disc 57 and an auxiliary plate 61 provided on the disc 57, and by fixing the auxiliary plate 61 to the disc 57 by means of bolts 63. The travelling wheels 8 thus constructed are mounted on the rotating shafts 56 such that the front ends, i.e., the portions to be in contact with the work surface, of the travelling wheels 8 are located inside the outer ends of said sealing members 38. As shown in FIG. 1, follower chain wheels 64 are fixed to the rotating shafts 56 to which the travelling wheels 8 are mounted. On a base 65 disposed on the frame 2 are mounted a motor 66 and a speed reducer 68 driven through a coupling 67. The output shaft end of said speed reducer 68 has main driving chain wheels 69 about which are trained endless chains 71 covered with a chain cover 70, which are further trained about said follower chain wheels 64 for rotating the travelling wheels 8. Referring to FIG. 2, a V
plurality of electromagnets 9 are mounted through annular rubber cushions 73 on brackets 72 arranged on the front surface of the frame 2 facing the work surface. The electromagnets 9 are arranged such that the front ends of the electromagnets 9 are located slightly inside the front ends, ie. the portions to be in contact with the work surface, of the travelling wheels 8. Thus, when the packaged blasting unit 1 is brought in close vicinity to the work surface, the whole packaged blasting unit 1 is attracted by magnetic force and kept just on the work surface, with the sealing members 38 being in tight contact with the work surface and with the electromagnets 9 being slightly spaced apart from the work surface. Between the electromagnets 9 and the sealing members 38 are provided access switches 74 for sensing the fact that the packaged blasting unit 1 is placed in the vicinity of the work surface and the sealing members 38 are in tight contact with the work surface. Said access switches 74 are fixed to brackets 75 disposed on the outer wall of the blasting chamber 7. With regard to the suspension of the frame 2, the pendulous basting apparatus is suspended at the left and right vertical sides of the frame 2 and at a lateral axial line (pins 78) substantially parallel with the plane of the opening and passing substantially through the center of gravity of the apparatus. Brackets 76 are arranged substantially in the middle of the left and right vertical sides of the frame 2. The suspending means of the frame 2 comprises said brackets 76, the pins 78 inserted to flange portions 77 provided on said brackets 76, a parallel bar 80 connected to the ends of wires 79 attached to the pins 78, and a wire 81 connected to said parallel bar 80. To the wire 81 is hitched the hook of a suitable suspending means which is not shown. As the wire 81 suspends the frame 2 at the left and right vertical sides of g the frame 2 and at said lateral axial line, the blasting apparatus can be readily rotated on said axial line so that the apparatus is capable of following smoothly the in clined work surface regardless of the degree of such an inclination. The frame 2 has a protecting stockade 82 composed of pipes and the like for guarding the packaged blasting unit 1 and other means. In the lower part of the abrasive storage hopper 34, a cover 83 for discharging abrasives is hinged to the conveyor casing 5.
Hereinafter explanations will be made on the operation ofthe pendulous blasting apparatus constructed as described above. The wire 81 is suspended from the hook of a conventional suspending means such as truck crane to move the frame 2 slowly close to the work surface. By the energization of the electromagnets 9, the sealing members 38 of the blasting chamber 7 are brought into tight contact with the work surface W in front of the travelling wheels 8, as shown in FIG. 2. After confirming this state by the sensing action of the access switches 74, the dust collector which is not shown in the figure is actuated to apply a suction to the interior of the separating chamber 6 through the duct and the opening 31. Then, the motors 11 and 19 are energized for rotating the projecting means 3 and the rotary bucket conveyor 4. By so doing, owing to the rotation of the rotary bucket conveyor 4, abrasives in the storage hopper 34 are scooped up by the bucket 13 of the rotary bucket conveyor 4 to move upward. The abrasives thus moved are discharged at the top portion of the rotary bucket conveyor 4 and nearly all of them are supplied to the chute 29 through the opening 22. When discharged, the majority of the abrasives accumulate on the upper flat portion a of the shielding plate 35 to fall continuously from the end of the upper flat portion 35a substantially uniformly in a layering manner. The remainder of the abrasives fall continuously from the buckets 13 in a nearly layering manner. In this case, since incoming air flow from the opening 28 is crossing the falling flow of such abrasives, relatively light particles, dust, and other foreign matters included in the abrasive flow are sucked and separated from the abrasive flow to be carried by the incoming air flow to the dust collector. In case some of the abrasives come in this suction air flow for one reason or another, the abrasives will collide with the bent portion 23a formed in the upper part ofthe inclined plate 23 to fall on the abrasive recovery passage 24 so that they are recovered in the part near the bucket 13 through said passage 24 and the abrasive recovery opening 36. Thus, the abrasives are never discharged in the dust collector. Dust in the dust removing chamber 37 is discharged to the outside of the apparatus through the connecting opening 31. At this time, of the entire dust floating in the dust removing chamber 37, the dust having a larger specific gravity falls in the abrasive recovery opening 36 through the space beneath the shielding plate 23, and only the fine dust particles floating in the chamber are sent to the dust collector through the connecting opening 31. The abrasive thus discharged from the top portion of the rotary bucket conveyor 4 are sent to the central part of the rotating blades 39 through the chute 29 to be turned at the distributor 48 toward the rotating blades 39. Then, the abrasives are supplied to the rotating blades 39 through the opening of the cage 51 to be accelerated and projected to the work surface. The abrasives projected as described above clean the work surface and fall, without flying to the outside of the apparatus thanks to the tight sealing of the sealing mem bers 38, on the inclined bottom plate 32 to slip thereon, finally reaching the abrasive storage hopper 34. With the above operation repeated, the work surface is cleaned continuously by raising and lowering the frame 2 using a lifting means not shown. As the electromagnets 9 are located on the frame 2 slightly inwardly of the travelling plane of the travelling wheels 8, the sealing members 38 of the blasting chamber 7 and the travelling wheels 8 are placed in tight contact with the work surface W, and the electromagnets 9 are placed with a small distance to the work surface W maintaining a magnetic attraction toward the work surface W. If the wire 81 is loosened, the frame 2 having the packaged blasting unit 1 is lowered sliding on the work surface W while being magnetically attracted to the work surface W with the sealing members 38 being in tight contact with the work surface W. Thus, the work surface is cleaned by slowly raising and lowering the wire 81 while keeping the packaged blasting unit 1 in operation. At this time, the vertical movement of the frame 2 is facilitated by the rotation of the rollers 59 supported by means of shafts in the peripheral recesses 58 of the travelling wheels 8. The vertical movement of the wire 81 is stopped when the frame 2 has arrived at the upper or lower end of the work surface to energize the motor 66 for rotating the travelling wheels 8 to move them laterally, which naturally results in the lateral movement of the frame 2. At the same time, the wire 81 is operated to move laterally synchronizing with the movement of the frame 2. In this instance, the travelling wheels 8 are rotated by the rotating shafts S6 rotated by the motor 66 through the chain wheels 69 and 64. Thus, the discs 57 of the travelling wheels 8 are rotated to move the frame 2 laterally. After the frame 2 has completed a lateral movement to a suitable position as described above, the frame 2 is again moved vertically in the manner described previously to begin the next cleaning operation of the work surface. During this operational period of time, the projecting head 3 is driven continuously without any interruption in operation. Vibrations caused by the high speed rotation of the projecting means 3 are hardly transmitted to the base 42 because all the vibrations in vertical and horizontal directions are absorbed by the vibration preventing rubber pieces 44 through which the attaching portion of the motor 11 is fixed to the base 42. The vibration in the axial direction of the bolt 45 is absorbed by the flange portion 44a of the vibration preventing rubber piece 44. The vibration at right angles to the axis of the bolt 45 is absorbed by the body of the vibration preventing rubber piece 44. The vibrations transmitted to the packaged blasting unit 1 are decreased in amount to a large degree as they are further absorbed by a rubber sheet 44b provided under the base 42. When the packaged blasting unit 1 is moved, while being operated, along the work surface, the rollers 59 never slip because rubber is lined on the outer surfaces of said rollers 59. If an inclined wall is to be cleaned, the package blasting unit 1 is lifted up by such means as a truck crane from a vertical position shown in FIG. 2 and is placed in an inclined position. In this case, when the degree of inclination of the packaged blasting unit 1 exceeds the resting angle at which abrasives begins to slide down and the rotary bucket conveyor 4 is rotated under this condition, the abrasives scooped up by the bucket 13 and moved upward are prevented to fall from the bucket 13 by the two end portions of the weir 13b and the side all 130 or the side plate 13c. Thus, the amount of abrasives falling from the bucket 13 can be limited to the slighest level with the result that the same as usual amount of abrasives is supplied to the projecting means and a uniform cleaning is carried out at all times. When the outer wall surface of a structure having a section of V or inverted V is to be cleaned, the cleaning can be performed by suspending the packaged blasting unit 1 by means of the wire 81 as shown in FIG. 2 and moving the packaged blasting unit 1 along the inclined wall surface.
As is apparent from the explanation in the foregoing, the present invention, on account of its unique construction comprising the rotary bucket conveyor 4 provided in the packaged blasting unit I mounted on the suspended frame 2, enjoys such distinct advantages as compact outline, reduced weight, and no occurrence of trouble thanks to smooth and sure recovery of abrasives in contrast to the conventional blasting apparatus such as the one utilizing a bucket conveyor combined with a screw conveyor and the one using a chain conveyor in which a chain having discs is moved in a pipe for recovering projected abrasives. When the rotary bucket conveyor 4 is directly driven by the motor 19 making use of the gear driving system as above in the figure, the whole apparatus is completely free of disadvantages such as shortened life of belt and slipping of rotary bucket conveyor due to the abrasives coming in between the contacting surfaces of belt and rotary bucket conveyor which are often experienced in the belt driving system in which a belt is trained about the outer periphery of rotary bucket conveyor. Since the separating chamber 6 is located close to the top portion of the rotary bucket conveyor 4, fine particles, dust, and other foreign matters included in the abrasives falling from the buckets are readily separated from the same, and the packaged blasting unit 1 can be constructed in a compact size. As can be seen in the embodiment shown in the Figure, the travelling wheel 8 comprises the disc 57 disposed at the end of the rotating shaft 56 and the disc 57 has on periphery thereof the recesses 58 spaced to each other at a required intervals. in each recess 58 is supported the roller 59 by means of the shaft 60 so that the roller 59 is rotatable in a direction crossing the direction of rotation of the disc 57. Outer surfaces of the rollers 59 constituting the travelling wheel 8 have rubber lined thereon to prevent slipping so that the travelling wheels 8 can move freely in both vertical and horizontal directions for effectively cleaning a given work surface to attain a high degrees of working efficiency. In addition, when the blasting apparatus in accordance with the present invention is suspended from a crane to be moved along the work surface, the blasting apparataus can be advantageously moved with the packaged blasting unit 1 being magnetically attracted to the work surface thanks to the construction of this embodiment in which the electromagnets 9 are located slightly inside the travelling plane of the travelling wheels 8. in the use of the electromagnets 9, considering a possibility that a very small amount of abrasives leaked out due to irregularites on the work surface to adhere to the electromagnets 9 to change their magnetic attraction and to badly affect the travelling of the packaged blasting unit 1, some provisions may be made for stopping temporarily the supply of electricity to the electromagnets 9 to avoid any trouble in the travelling of the packaged blasting unit 1. Further, the vibration preventing means are doubly arranged for the motor 11 for driving the projecting means 3 and the base 42 of the motor 11 to decrease greatly the vibrations caused by high speed rotation of the projecting means 3 so that operations at high places such as the cleaning of side of aship can be performed under a more stable and safe condition.
Thus, the pendulous blasting apparatus in accordance with the respect invention is of a simple construction, can be readily handled with low expenses, and can be used by suspending from conventional lifting means such as a truck crane to attain a high working efficiency. It can be used in cleaning vertical and inclined wall surfaces of large structures including side of a ship and has many advantages as exemplified particularly by the fact that when cleaning an inclined wall surface abrasive can be recovered uniformly and smoothly to achieve an even cleaning effect.
1. A pendulous blasting apparatus comprising:
a packaged blasting means adapted to be suspended by 2 9p n abl de nin ur assins ina n opening, a centrifugal projecting means adapted to project abrasives through said opening to a vertical or inclinedblast cleaning surface and sealing members made of rubber or synthetic resin and provided around said opening and adapted to surround said blast cleaning surface for preventing the jumping out of the abrasives projected to said blast cleaning surface;
an abrasive recovery means mounted on said packaged blasting means integral therewith and including an abrasive storage hopper adapted to hold the abrasives which fall after finishing the cleaning operation and dust resulting from said cleaning operation, a doughnut-shaped rotary bucket means having a plurality of buckets adapted to continuously scoop up and recover the abrasives and dust in said abrasive storage hopper and a separating chamber arranged at the top of said abrasive recovery means and adapted to receive the abrasives and dust recovery by said buckets for separting the abrasives from the dust by applying an air suction to said abrasives and dust so that the separated abrasives are supplied to said centrifugal projecting means,
said doughnut-shaped rotary bucket means having an outer periphery thereof, a flat portion and gear teeth protruding radially from said flat portion, and including a rotary driving means having a pinion for rotationally driving said rotary bucket means by meshing with said gear teeth and receiving rollers adapted to rotatably support said rotary bucket means by engaging with said flat portion and also adapted, when said blasting apparatus is inclined, to be in contact with the sides of said gear teeth for preventing the movement in the axial direction of said rotary bucket means; electromagnets provided on said packaged blasting means for bringing said sealing members into tight contact with said blast cleaning surface; and
wheels permitting free travel on the blast cleaning surface and for moving said packaged blasting means along said blast cleaning surface.
2. A pendulous blasting apparatus according to claim 1, wherein said wheel comprises a disc fixed to a rotating shaft provided in said packaged blasting means, a plurality of recesses arranged on the periphery of said disc in the radial direction thereof and spaced to each other at equal intervals, and travelling rollers one each provided in each said recess to be rotatable in the direction at right angles to the direction of said shaft.
3. A pendulous blasting apparatus according to claim 2, wherein the outer periphery of each said travelling roller is lined with rubber to move said travelling rollers smoothly on said blast cleaning surface without slipping and to prevent the damage of said blast cleaning surface.
4. A pendulous blasting apparatus according to claim 1, wherein said centrifugal projecting means includes a driving electric motor and abrasive projecting blades directly connected to the rotation shaft of said electric motor, and said centrifugal projecting means further has vibration preventing rubber pieces through which said electric motor is mounted on said centrifugal pro- 10 jecting means to prevent the vibrations caused by said electric motor and transmitted to said packaged blasting means so that a tight contact is established between said sealing members and said blast cleaning surface.
5. A pendulous blasting accordng to claim 1, wherein said separating chamber has a communication passage in communication with the moving passage of said rotary bucket means leading from said storage hopper to said top, such that abrasives changing their direction due to said air suction applied in said separating chamber will fall without being supplied to said centrifugal projecting means but will fall on the communication passage and then be received by the bucket through said communication passage.
6. A pendulous blasting apparatus according to claim 1, wherein said bucket has a dividing weir adapted to divide the interior of the bucket so that abrasives scooped up by the bucket are prevented from falling out of the bucket by the end portion of the weir when said blasting apparatus is inclined.