Patent Application
20100218354
The present application relates to a method and apparatus for smoothing a metal surface and more particularly to removing slag and/or burrs from a metallic surface adjacent a cut.
Steel plate that is flame cut to a particular size and shape or which includes flame-cut openings is widely used to build a variety of metal products. When such metal is cut, using an oxygen-torch flame or by other means, burrs and/or slag often extend above the surface of the metal adjacent the cut. In many applications these irregularities must be removed before the metal part is incorporated into an assembled product.
There are currently several approaches to burr or slag removal. Hand-held grinders, wire wheels, hammers, chisels, or the like, must be used for large metal slabs after they have been cut. Some applications are suitable for motorized machines having conveyor belts that operate in conjunction with wire wheels, abrasive discs, or sanding belts. Smoothing small parts may be accomplished using hand-held devices or the parts may be fed into a deburring machine or tumbled or vibrated in tubs with abrasive stones.
In addition to the foregoing, some applications use rollers or spherical metal balls that apply pressure to the surface of the metal. These are then moved across the surface of the metal resulting in lateral impact to the slag or burr, which knocks it off.
The hand-held devices are noisy and when used on big pieces may require the operator to work while kneeling. The ensuing noise, dust, and discomfort make this a difficult job for which it is hard to find and keep workers.
Both the motorized machine and hand-held devices tend to mar, gouge, and deform the otherwise smooth edge and/or surface of a metal plate when used to smooth the edge of a cut. Many applications require a smooth metal surface for either aesthetic or functional reasons. Prior art rollers and metal balls suffer from this same disadvantage, i.e., the pressure against the edge or the smooth metal surface results in gouging and deformation.
Indicated generally at 10 in
A cup 20, also referred to herein as a head, is connected to the drive shaft via a mechanical coupling, e.g., a threaded connection (not visible). As a result, when the motor runs, cup 20 rotates about axis 14. The cup includes a cavity 22, also referred to herein as an annular groove. A substantially planar surface 24 forms a side wall that defines one side of the cavity. The cup further includes downwardly directed surfaces 26, 28, which are also substantially planar. A central post 30 is formed within the cavity about axis 14. A disc 32, also referred to herein as a retainer, is mounted on the lower end of post 30 via a countersunk bolt 34, which is received in a threaded connection formed in the center of the post. Disc 32 includes a frusto-conical surface 35. Three steel balls 36, 38, 40 are received within the cup. A fourth ball 42 is visible in the view of
A flexible guard 44 is shaped like a downwardly-directed cup and seals at its upper end around shaft housing 16. The lower end thereof engages against a substantially planar workpiece 46, in this case a piece of metal plate that has been flame cut, thus leaving a line of slag 48 that extends above a substantially planar surface 50 of the metal plate along a cut edge 52. In the view of
As can be seen in
In operation of the tool 10, a user of the tool stands adjacent cut edge 52 of workpiece 46. The tool is positioned as shown in
When the motor (not visible) rotates shaft 12, cup 20 begins clockwise rotation about axis 14 thus driving each of the balls into a respective one of lobes 54-60 as shown in
The downward force exerted by each of balls may be enough to extend each ball to its lowermost position as shown in
If the balls are fully lowered as they all rotate on surface 50 of the workpiece, after the tool is moved to the edge, as described above, each ball strikes slag line 48 with the lowermost portion of the ball substantially tangent to surface 50. The balls, however, may not be fully extended due to the weight of the tool. If so, the balls drop responsive to the force of gravity after they move over edge 52 off of surface 50 at the trailing end of the tool. The lowermost portion of each ball may be 1/64 inch to 1/32 inch below surface 50 as it moves across edge 52 and back over the surface at the leading end of the tool. This effectively removes the slag without denting, beveling, or chamfering edge 52 because the balls are free to move upwardly in the cup and may do so very rapidly in response to the ball striking the slag line slightly below surface 50. After rapid upward movement from such an impact, the centrifugal force again moves the ball to surface 24, which forces the ball down into position for again striking slag line 48. As a result, slag is effectively removed and neither surface 50 of the workpiece nor edge 52 is damaged. The space within the cup also permits bits of slag knocked from the slag line to fall easily from the cup, as opposed to becoming jammed between one of the balls and the cup.
Turning now to
A splined pulley 80, shown in somewhat schematic form, is keyed to main shaft 66. A suitable motor (not shown) engages pulley 80 via a belt (also not shown) to impart rotation to the main shaft for turning the head of tool 64.
In general, tool 64 operates similarly to tool 10. Tool 64, however, facilitates quick and easy release of each of the balls, like ball 38, from the cup. This is achieved by simply applying downward pressure to ball retention shaft 68 at the upper end thereof. When shaft 68 moves downwardly relative to main shaft 66, thus compressing spring 70, disc 32 moves downwardly relative to the lower end of post 30, as shown in
Turning now to
Turning now to
The motor shaft directly drives one of heads 86, 88, 90 with the other two being driven by belts engaged with pulleys on the motor shaft and on the shaft of each of the other two heads, as shown. As a result, when one of power switches 98, 100 is switched, all three head rotate to remove slag as described above. The action of three heads each containing 8 balls increases the impacts delivered by the balls to a slag line (not shown in
Turning now to
A conveyor belt 122 is located beneath the cups, like cup 120. The conveyor belt supports and transports a workpiece (not shown) beneath the row of cups in the direction of arrow 124. A plurality of hold-down discs, like hold-down disc 126, and hold-down rollers, like hold-down roller 128, holds the workpiece in position as it moves beneath the cups.
Machine 106 permits fine adjustment of where each of the balls strikes the flame-cut edge of a workpiece relative to the surface of the workpiece. As discussed in connection with tool 10 above, it may be desirable to adjust the relative positions of the cups and workpiece so that the lowermost portion of each ball is about 1/64 inch or 1/32 inch below the surface of the workpiece as the ball strikes the edge and slag line when moving from off the workpiece to over the workpiece. This provides a strong impact to dislodge slag. And because the ball can move freely within the cup responsive to the impact, neither the edge nor the surface of the workpiece is peened, marred or otherwise disfigured.
Some embodiments of the invention have been described above, and in addition, some specific details are shown for purposes of illustrating the inventive principles. However, numerous other arrangements may be devised in accordance with the inventive principles of this patent disclosure. Further, well known processes have not been described in detail in order not to obscure the invention. Thus, while the invention is described in conjunction with the specific embodiments illustrated in the drawings, it is not limited to these embodiments or drawings. Rather, the invention is intended to cover alternatives, modifications, and equivalents that come within the scope and spirit of the inventive principles set out in the appended claims.
