US2918758A

US2918758A - Centrifugal blasting machine

Info

Publication number: US2918758A
Application number: US637109A
Authority: US
Inventors: Kenneth H Barnes
Original assignee: Wheelabrator Corp
Current assignee: Wheelabrator Corp
Priority date: 1957-01-30
Filing date: 1957-01-30
Publication date: 1959-12-29
Anticipated expiration: 1976-12-29
Also published as: GB865217A; FR1198548A

Description

Dec. 29, 1959 K. H. BARNES 2,918,758

CENTRIFUGAL BLASTING MACHINE 4 Sheets-Sheet 1 Filed Jan. 30, 1957 Fr 2 K INVENTOR.

K 71226272 Jf. Barnes Dec. 29, 1959 K. BARNES 2,913,758

CENTRIFUGAL BLASTING MACHINE Filed Jan. 30, 1957 4 Sheets-Sheet 2 Fla F2624 INVENTOR.

Ker/126171 H Ear-Hes J 7' fl zerzz Dec. 29, 1959 K. H. vBARNES 2,918,758

CENTRIFUGAL BLASTING MACHINE Filed Jan. 30, 1957 4 Sheets-Sheet 3 INVENTOR. Kennefh Ji. Barnes BY gnu, M

- flh orrz 61 5 Dec. 29, 1959 K. H. BARNES Filed Jan. 30, 1957 4 Sheets-Sheet 4 United States Patent CENTRIFUGAL BLASTING MACHINE Kenneth H. Barnes, South Bend, Ind., assignor to Wheelabrator Corporation, Mishawaka, Ind., a corporation of Nebraska Application January 30, 1957, Serial No. 637,109

11 Claims. (CI. 51-13) This invention relates to a machine in which abrasive particles are thrown at high velocity upon work continuously being tumbled within a confined space to clean the surfaces of the work, as in the removal of sand from metal castings or burrs and flashing from molded parts, and it relates more particularly to a blasting machine of the type described embodying improvements which enable more eflicient use and operation of the machine and decreased costs in operation from the standpoint of wear and replacement of parts, and it is an object of this invention to produce a machine embodying such improvements.

More specifically, it is an object of this invention to produce a blasting machine of the type described which provides greater access to the interior thereof for the introduction and removal of work; which embodies means of protecting parts otherwise exposed, to minimize work damage and destruction of parts thereby, not only to increase the life of the elements of the machine but materially to increase the capacity and output of the machine; which enables automatic operation for opening and closing the machine in loading and unloading the machine; which embodies means to prevent loss of abrasive material from the machine to the surrounding atmosphere during operation; which prevents abrasive and work from becoming lodged between parts of the machine in operation to jam the machine or otherwise cause damage or breakdown of parts, and which combines these improvements in combination with an improved endless carrier upon which the work rests to improve the operation of the machine and its efliciency in operation.

These and other objects and advantages of this invention will hereinafter appear and, for purposes of illustration, but not of limitation, an embodiment of the invention is shown in the accompanying drawings, in which Figure 1 is a perspective front elevational view of a machine embodying features of this invention;

Figure 2 is a sectional view taken along the line 22 of Figure 1, showing the door guide structure in detail;

Figure 3 is a fragmentary elevational view in perspective of the front side portion of the machine showing the shielding for protecting the elements of the machine in the wider door opening;

Figure 4 is a fragmentary view in elevation from the inside of the door structure shown in Figures 1 and 2;

Figure 5 is a sectional view taken along the line 5--5 of Figure 4;

Figure 6 is a front elevational view of the side frame structure of the machine;

Figure 7 is an elevational view of the inside of the side structure of the machine shown in Figure 6, with elements of the machine omitted to enable illustration of the details of the machine; and

Figure 8 is a sectional elevational view of the bottom portion of the door structure of the machine.

Description will be made hereinafter to the various improvements embodied in a blasting machine of the type described in the Peik Patent No. 2,104,055 and the Turnbull Patent No. 2,131,772. On occasion, reference will be made to the structure of the prior art as represented by the aforementioned patents to point out deficiencies which are overcome by the practice of this invention.

Referring now to Figures 1 and 3, the numeral 10 represents flight bars which are arranged with the front and back edges in overlapping relation one with the others adjacent thereto to provide a continuous surface on which the work to be blasted is carried for tumbling. The ends of the flight bars are secured to pads (not shown) which extend inwardly from link members pivoted one onto the other in endless succession to provide a continuous link chain which operates about rollers, as represented by the roller 12 at the front or door portion of the machine and which includes a similar roller member for rotational movement about a parallel axis rearwardly and below the first roller and which also includes a driving sprocket mounted for rotational movement about a parallel axis above the first roller and rearwardly thereof.

The top flight of the endless belt,.as guided by th link chains, turns about the periphery of spaced drums 14 located between the roller 12 and the sprocket to define a line of travel which proceeds from the roller 12 downwardly as deflected about the lower periphery of the drum 14 and up the rear edge to the sprocket which is located forwardly and above the inner periphery of the drum so that the belt traveling with the link chain forms a valley wherein most of the work rests, and a portion which extends upwardly and forwardly from the rear of the valley to cause the work to rise and tumble forwardly as the chain link and flight bars are advanced in operation in the direction of the arrow in Fig. 3. When unloading the machine, the direction of movement of the chain link and attached flight bars is reversed so that the work will be carried forwardly over the hump provided as the chain link turns about the roller 12 to pass rearwardly beneath the upper flight and up toward the sprocket. The flight bars, the chain links, and the attached parts, form no portion of the invention and therefore a detailed description thereof will not be given except by way of reference to the aforementioned copending application.

Suffice it to say that the drums 14, separately mounted for rotational movement and lined on their inner surfaces with wear plates 16, form the side walls of a space having for its bottom and back walls the endless belt of flight bars traveling about the periphery portions of the drums. The space is concealed at its top by the sheet metal housing 18 and at its front by a door 20 mounted for shifting movement between open position for loading and unloading the space with work and a closed position for concealing the space with the work carried on the belt conveyor for treatment. When the work space is concealed, abrasive particles can be thrown downwardly centrifu'gally at high velocity by one or more centrifugal blasting wheels 22 mounted on the top of the housing with the spray pattern of abrasive particles directed downwardly onto the work throughe suitable openings in the top wall of the housing.

An important concept of this invention resides in the means for enlargement of the access opening to the machine for loading and unloading the work. To the present, the access opening has been confined to the space between the drums 14 since, otherwise, difficulties have been encountered in the protection of the chain links and rollers on which the flight bars are carried. Exposure of such elements and the walls of the housing to the abrasive particles bounding and rebounding within the-confined space would quickly lead to theiracomplete destruction. It was believed necessary also to confine the opening to the area between the drums in order to effect a suitable seating relation which minimizes the entrance of abrasive particles into spaces between moving elements and to avoid the entrance of work or portions thereof into openings between the drum, roller, flight bars or chain link members whereby continued operation of the machine might cause distortion or destruction of parts, thereby to cause shutdown of the units for repair or for replacements of parts.

Even though limited to the space between the drums 14, many of the difllculties previously pointed out were still being experienced by reason of the spaced relationships existing between the flight bars in operation and between the ends of the flight bars and the drums and door members whereby abrasive particles were lost or thrown into the atmosphere and work or portions thereof Were able to become lodged between the moving parts to cause jamming.

Enlargement of the access opening is achieved in accordance with the practice of this invention with concurrent improvement in the protection of parts by the modification in the construction to include a shielding member 22, illustrated in Figs. 3, 6 and 7 of the drawings, as a metal casting which fits tightly over the roller 12 over which the link chain travels at the front end of the machine. The shielding member 22, formed of an abrasive and wear-resistant metal, comprises a rearward and upwardly extending portion 24 of curvilinear shape corresponding to the periphery of the drum and dimensioned to cover the space between the periphery of the drum adjacent the roller and the side wall 26 of the housing to conceal the space therebetween.

Extending forwardly integrally from the roller edge portion of the upright curvilinear section 24 is a forwardly extending portion 28 concentric with the roller 12 and dimensioned to extend crosswise between the adjacent edge portions of the flight bars 10 and the side wall 26 of the housing to conceal the space therebetween. The two curvilinear portions converge one into the other and extend beyond the point of convergence to form a nose piece 30 which projects rearwardly and downwardly into the region between the roller 12 and the drum 14 to effect a separation therebetween which provides further protection against the formation of open spaces between the drum and roller through which abrasive particles might be thrown against the chain links or the housing walls to cause wear or deterioration.

The shield 22 comprises an integral member having a side wall section 32 provided with openings for attachment of the shield, as by bolts 34, to the side wall of the housing or to the frame of the machine. The curvilinear portion 28 concentric with the roller 12 and which extends about the chain links is provided with a downturned apron or flange 36 at its inner euge and which extends downwardly to a level below the top surfaces of the flight bars 10 as they pass with the chain about the roller 12 to provide a sealing relation between the shield and the flight bars sufiicient to prevent openings of a dimension in which work might become entrapped.

The shielding member 22 extends forwardly for a distance beyond the effective range of the abrasive particles being thrown in the work space and to a position to be contacted by the door 241, seen in closed position, thereby etfectively to seal the work space from the other parts of the machine and the outside atmosphere. Thus the access opening at the front of the machine has been extended beyond the spaced drums to include the space covered by the chain links and rollers, thereby to make available the entire area between the side walls of the housing. The increase in the access opening makes the work space more readily available for loading and unloading with less danger of the wear or destruction of parts.

In addition to the increase in the dimension of the opening for loading and unloading the machine, the described improvement makes it possible to embody a door structure which offers a better sealing relation for preventing loss of abrasive materials in operation and better protection of the door structure while also making it possible to employ a door assembly which is amenable to automatic operation for opening and closing movements In the past, with the smaller door opening, use has been made of a flat metal plate pivotally mounted for rocking movement about its upper edge portion to between open and closed positions. The plate was dimensioned to cover the open space between the top wall of the housing and the portion of the flight bars traveling over the forward periphery of the roller in the attempt to conceal the Work space therebetween. The plate was provided with a resilient apron extending from the lower edge thereof which was adapted to be draped by hand about the curvilinear portion of the roller and flight bars in the attempt to provide greater protection to the operator and to the machine parts. The door assembly described was incapable of providing a sufficiently tight seal for the protection desired, and it required consider able manual operation and adjustment in use.

in construction of a door for automatic operation and for better sealing and protection, it has been found desirable to subdivide the door structure into separate components, one of which comprises a straight section capable of linear movement to enclose the straight run between the hump of the flight bars traveling about the roller and the upper end of the access opening, and the other of which comprises a flexible member capable of shifting movement in a curvilinear path to cover that portion of the opening about the roller beneath the lower edge of the drum and which extends continuously from the lower edge thereof to the lower end of the access opening.

Referring now to Figs. 1, 2, 5 and 6 of the drawings, the upper door part it is formed of a heavy metal plate 42 dimensioned to have a width corresponding to the width of the opening between the side walls 26 of the machine housing and a length corresponding to the distance between the upper end of the door opening ad jaccnt the top wall of the housing and the tangent with the periphery of a cylinder slightly greater than the cylindrical section formed by the flight bars traveling about the roller 12. The door plate is preferably provided with reinforcing and stiffening members on its outer face, preferably adjacent its edges, as represented by the panel members or beams 44, fixed to the outer walls of the plate, as by welding or the like.

The inner wall of thet door plate is protected from wear by the abrasive particles by a replaceable rubber blanket 46 which is held by a plurality of hold-down straps 4:; of wearresistant material. The straps are fixed to the door plate to grip the rubber lining 46 therebetween by means of bolts 50 or other equivalent securing means. The rubber lining 46 and the hold-down plates 48 terminate short of the lateral edges of the door plate 42 by an amount to permit the attachment of wear plates 52 in the form of a plurality of elongate sections of wear-resistant material to be secured to the lateral edges along the side wall of the door plate, as by bolts 54. The wear plates are secured in end-to-end relation to provide a continuous surface capable of functioning as a bearing surface in sliding relation with a door frame member 56 during movement of the door plate between raised and lowered positions of adjustment.

A guide flange 58 extends outwardly from the lateral edges of the door plate to be received in guiding relation within corresponding grooves formed by elements fixed to the forward edges of the housing adjacent the door opening for guiding the door plate in movement between open and closed positions. The guide flanges 58 are provided in the form of an elongate angle iron having one face 60 fixed, as by welding, to the outer edge portion of the door plate while the flange 58 extends perpendicularly from the edge thereof.

The recess 62 in which the flange 58 is received is provided by an angular plate 64 in the form of an angle iron secured at one edge 66 to the outer edge of the side plate 68 of the housing which defines the door opening, while the adjacent arm portion 70 of the angle iron extends inwardly with the flanged portion 72 extending rearwardly to provide the recess 62 in which the guide flange 58 is received. Also secured to the inner wall of the side plate 68 but spaced rearwardly of the angle iron 64 is another member having a flanged portion 56 extending inwardly from the side edge for a distance beyond the end of the recess 62 to define a slot between the flange 56 and the edge of the flange 72 through which the end structure of the door extends to be confined within and between the elements with the wear plates 52 resting on the inner surface of the flange 56 for sliding support during opening and closing movements of the door.

It will be apparent from the structure described that the interfitting relationship between the parts provides for a seal in the end structure of the door assembly which militates against flow of abrasive particles therebetween with such force as to cause wear on the machine or elements thereof since the particles lose their force when required to change directions at least three times for passage through the space, as might be available between the flange 56 and the wear plate 52, between the edge of the door and the side wall of the machine and between the guide flange 58 and the

elements

70 and 72 defining the recess in which the flange is received. Thus a sealing relationship is provided while also making available an interconnected and guided relation which permits the door plate to be actuated by automatic means to between open and closed positions.

Various means may be provided for actuating the door plate assembly to between raised or open and closed or lowered positions. One such suitable means, illustrated in Fig. l of the drawings, comprises a plurality of cables 74 secured at their free ends to an upper portion of the door plate while the other portions of the cables are wound about pulleys 76 fixed for rotational movement on a shaft 78 extending crosswise at the front of the housing between trunion members 80 mounted on the top wall of the housing. Means, such as a reversible electric motor 82, is operatively connected to the shaft 78 for rotation thereof in one direction or the other to wind up the cable 74 for raising the door plate and for unwinding the cable to lower the door plate.

The bottom door section comprises a panel 84 formed of rubber or other resilient, Wear-resistant material, having guide members 86 on the edges thereof adapted to be received in sliding relation within guide channels extending continuously downwardly from the lower edge of a similar guide section, as described in the upper door plate assembly.

The lower edge of the flexible panel 84 is fixed, as by bolts 88, onto a closing plate 90 of metal extending across the door opening and which is also received in guidingrelation at its edges in the curvilinear groove guide. Secured to the plate is a retainer rod 92 which extends crosswise adjacent the inner wall of the flexible panel. Link members in the form of rigid metal bars 94 are pivoted at one end on the retainer 92 while the other end 96 is pivoted between yo-kes 98 on the end of actuating arms 100 mounted for free rotational movement about pivot pins 102 fixed by closing plates 104 to a lower rearward portion of the frame of the machine. The actuating arms 100 are caused to rock about their pivots by an air cylinder 106 or other displacement means pivoted at its base end, at 108, upon a support 110, while the piston rod 112 is pivoted at its outer end on a pin 114 on an arm rigid with the actuating arm 100 and offset from its pivot 102.

Thus, displacement of the piston outwardly in the fluid cylinder will cause the actuating arm 100 to be rocked upwardly in a counter-clockwise direction in Fig. 8 about its pivot 102 to cause its outer end to swing upwardly over a stillv greater distance to displace the link 94 and the attached resilient door panel 8-4 upwardly into contacting relation with they lower edge of the door plate, or until otherwise stopped to close the lower door opening. Displacement of the piston inwardly in the cylinder by flow of pressure fluid into the head end of the cylinder will cause the actuating arm 100 to rock downwardly about its pivot to cause the door panel to be lowered within its guide to open position. To assist in the guiding relation and to provide greater rigidity to the assembly, a guide plate 116 is fixed to extend downwardly from the closing plate for travel in an extension of the guide slide formed in the side wall of the housing, said guide plate 116 and slide preferably being in the form of a straight section for avoiding binding in operation.

It will be understood that other equivalent means for actuating the upper and lower door panel sections may be employed without departing from the spirit of the invention. In the event that suflicient leverage can be made available, as in units of smaller dimension or capacity, manual means may be employed for effecting displacement ,of the described door elements between open and closed positions. Usually it is desirable in closing the unit after loading to lower the top door plate prior to actuation of the bottom door section to raise the door section to closed position. Sequence of operation may be employed in actuating the sections to open position by raising the top and lowering the bottom.

It will be apparent that the widening of the door opening in the manner described will provide a number of material improvements over the structures heretofore employed. Before the doors were widened the seals were exposed to the erosion and wear caused by the abrasive material. If particles entered the frame structure, the frame would become deformed with resultant loss in sealing. An important concept of this invention resides in the ability now to locate the seals outside of the danger zone of the particles being thrown. Thus particles will find it more diflicult to enter the frame and the seals will not be exposed to Wear.

Where, in the past, entrance of abrasive particles or work into the frame or seals would cause distortions so that a sealing relation could no longer be effected, now the conveyor seals are out of danger and they are further made independent of the door seals so that one would no longer have any effect upon the other. Thus it might become possible for the seals to become deformed without affecting the ability of opening and closing the door, and vice versa.

It will be apparent that changes may be made in the details of construction, arrangement and elements em ployed for operation without departing from the spirit of the invention, especially as defined in the following claims.

1. In a cleaning machine of the type described having a housing, a conveyor in the housing upon which the work is supported, guide rollers at the front and back ends of the conveyor for guiding the conveyor in movement, laterally spaced apart drum members which rotate with the conveyor between the front and back rollers to deflect the conveyor in its path of travel about the lower periphery thereof during travel between the front and back rollers and defining with the conveyor and housing a confined space having an access opening extending from below the roller assembly at the front to the opening at the top, means for extending the access opening beyond the spaced drums comprising a shield member formed of rigid, wear resistant material having converging curvilinear portions one of which extends upwardly for a distance concentrically with the drum and outwardly to the adjacent side wall of the housing and the other of which extends forwardly to the access opening concentrically with the front roller from the edge of the conveyor to the side wall of the housing, and means for securing the shield member rigidly to the housing in position of use.

2. A machine as claimed in claim 1 in which the shield member includes an apron downturned from the inner edge of the curvilinear portion concentric with the roller and dimensioned to have a length to extend below the edge of the conveyor elements turning about said roller.

3. A machine as claimed in claim 1 in which the shield member includes a portion at the point of convergence which continues to extend rearwardly into the area between the drum and front roller to effect a clear line of separation therebetween.

4. A machine as claimed in claim 1 in which the shield member includes a side plate integrally joining the outer edges of the converging curvilinear sections.

5. In a cleaning machine of the type described having a housing, a conveyor in the housing upon which the work is supported, guide rollers at the front and back ends of the conveyor for guiding the conveyor in movement, laterally spaced apart drum members which rotate with the conveyor between the front and back rollers to deflect the conveyor in its path of travel about the lower periphery thereof during travel between the front and back rollers and defining with the conveyor and housing a confined space having an access opening extending from below the roller assembly at the front to the opening at the top, a door frame defining the lateral edges of the access opening between the roller and the top of the access opening in the housing comprising a rigid metal member fixed to the outer edge of the housing and having a portion extending substantially perpendicularly inwardly from the side wall of the housing and a flange extending rearwardly substantially perpendicularly from the free edge of the inwardly extending portion to define a groove therebetween and a slide plate fixed to the side wall of the housing and spaced inwardly from the metal member by an amount greater than the length of the flange and dimensioned to be greater than the distance between the flange and the side wall of the housing to extend beyond the flange and provide a slotted portion therebetween, and a door panel in the form of a metal plate dimensioned to have a length corresponding to the access opening between the roller and the top of the access opening in the housing and a width less than the distance between the side walls of the housing but greater than the distance between the flanged members defining the recess in the edges thereof and a guide flange fixed to the lateral edge portions of the door plate in position to extend beyond the flange into the formed recesses for guiding the door in sliding movement between open and closed positions and for sealing the space within the housing from the outside atmosphere when the door is in closed position.

6. A machine as claimed in claim 5 which includes power operated means and means interconnecting the power operated means with the door panel to effect vertical displacement of the door panel between open and closed positions.

7. A machine as claimed in claim 5 which includes a lining on the inner surface of the door panel formed of a replaceable, resilient, wear resistant material.

8. A machine as claimed in claim 7 which includes hold-down straps on the side of the lining opposite the door panel and which are connected to the door panel to secure the lining in position of use therebetween.

9. A machine as claimed in claim 7 in which the lining terminates short of the lateral edges of the door panel and which includes wear plates fixed to the inner surfaces of the door panel adjacent the lateral edges thereof in position to engage the slide plates fixed to the side walls of the housing.

10. in a cleaning machine of the type described having a housing, a conveyor in the housing upon which the work is supported, guide rollers at the front and back ends of the conveyor for guiding the conveyor in movement, laterally spaced apart drum members which rotate with the conveyor between the front and back rollers to deflect the conveyor in its path of travel about the lower periphery thereof during travel between the front and back rollers and defining with the conveyor and housing a confined space having an access opening extending from below the roller assembly at the front to the opening at the top, a lower door frame defining the lateral edges of the access opening between the roller and the bottom edge of the access opening in the housing, a lower door panel formed of a flexible wear resistant material dimensioned to extend crosswise between the lower door frame members and to have a length corresponding to the length of the access opening bounded by the lower door frame, a guide plate fixed to the lower edge of the flexible door panel, a linking means pivotally connecting the end of the link with the guide plate, an actuating arm pivoted at its rearward end upon the housing, means pivotally interconnecting the free forward end of the actuator with the free end of the link, and means operatively engaging the actuator arm intermediate its pivot for displacement of the arm for rocking movement about its pivot to effect opening and closing movements of the door panel between lowered and raised positions respectively.

ll. A cleaning machine as claimed in claim 6 which includes a lower door frame defining the lateral edges of the access opening between the roller and the bottom edge of the access opening in the housing, a lower door panel formed of a flexible wear resistant material dimensioned to extend crosswise between the lower door frame members and to have a length corresponding to the length of the access opening bounded by the lower door frame, a guide plate fixed to the lower edge of the flexible door panel, a linking means pivotally connecting the end of the link with the guide plate. an actuating arm pivoted at its rearward end upon the housing, means pivotally interconnecting the free forward end of the actuator with the free end of the link, and means o-peratively engaging the actuator arm intermediate its pivot for displacement of the arm for rocking movement about its pivot to effect opening and closing movements of the door panel between lowered and raised positions respectively in which, when the lower door panel is in raised position, the upper end thereof is in end to end relation with the lower edge of the door panel.

References Cited in the file of this patent UNITED STATES PATENTS 2,533,265 Keeper Dec. 12, 1950