US3710515A

US3710515A - Abrading apparatus

Info

Publication number: US3710515A
Application number: US00150312A
Authority: US
Inventors: W Kulischenko; J Callahan
Original assignee: Pennwalt Corp
Current assignee: Pennwalt Corp
Priority date: 1971-06-07
Filing date: 1971-06-07
Publication date: 1973-01-16
Anticipated expiration: 1990-01-16

Abstract

In abrading apparatus, wherein a nozzle issues a jet of airborne abrasive material and a traversing mechanism moves in a given direction, a motion translating device cooperates with the traversing mechanism to move the nozzle transverse to the given direction.

Description

United States Patent 1 1 Kulischenko et al. 1 Jan. 16, 1973 1541 ABRADING APPARATUS [56] References Cited [75] Inventors: Walter Kulischenko, East Brun- UNITED STATES PATENTS Swlck; Calm, Lamka 1,005,750 11/1926 Hoevel ..51/11 x Ham, 1,882,541 10/1932 Billman ..5l/8 v e 3,516,204 6/1970 Kulischenko ..51/8 [73] Assgnee' 52 ph'ladelpha 3,534,503 10/1970 Kulischenko ..51/8

[22] Filed: June 7, 1971 Primary ExaminerLester M. Swingle AttrneyEdward A. Sager [21] Appl. No.: 150,312

7 [57] ABSTRACT [52] US. Cl ..51/8 In abradin ap ziratus, wherein a nozzle issues a 'et of 8 P J [51] Int. Cl ..B24c 3/02 airborne abrasivematerial and a traversing mechanism [58] Field of Search ..51/8, 11 moves in a given direction, a motion translating device cooperates with the traversing mechanism to move the nozzle transverse to the given direction.

Claims, 4 Drawing Figures 44 54 so 58 42 l2 7 32 3 i 62 3 i 52 1|: 1 v 33\ 64 so r n f 66 86 I d 43 76 E/ e l8 I8 4 ABRADING APPARATUS DISCLOSURE OF THE lNVENTlON This invention relates to abrading apparatus, especially those of the type having a movable nozzle issuing a jet of airborne abrasive material to remove material from a workpiece. More particularly, the invention is directed to an abrading apparatus in which motion of a traversing mechanism for moving the nozzle is translated into a path which is in angular relationship with the stroke of the traversing mechanism, thus providing simply convertible means for reciprocating the nozzle optionally along either one of two paths.

Although not so limited, the apparatus is especially useful for trimming to a desired electrical value resistors or other electrical elements printed across parallel conductors on a substrate, by abrasive removal of the printed material. The path of the abrasive jet is usually in a fixed linear path between and parallel to the conductors. However, if one pair of conductors is disposed at right angles to another pair of conductors on the same substrate or workpiece, and if trimming is to be accomplished without reorienting the workpiece as by turning it 90, it is desirable to alter the path of the abrasive jet. The present invention accomplishes just that by incorporating a device which is rugged, dependable, effective, very simple and economical. Furthermore, the device is constructed and arranged to minimize exposure to premature wear and damage by stray abrasive particles, since it is positioned well above both the workpiece holder and the exhaust system which carries off spent abrasive material.

According to the invention, the abrading apparatus includes a motion translating device which cooperates with a driving member of the traversing mechanism. A cam is attached to the driving member in position to engage a roller and thereby drive a supporting slide transversely. The abrading nozzle is also carried by the slide and it is movable therewith, transverse to the stroke of the driving member. In its preferred form, the cam is wedge shaped, having each of two converging camming surfaces at a 45 angle to the stroke path of the driving member. The cam is positionable by means of a transverse slot and a securing screw to present a selected one of the two camming surfaces for engagement with the roller, whereby camming motion is transmitted to the nozzle in one sidewise direction or the other. ln either direction of camming movement, a spring yieldably resists the camming force and subsequently biases the slide to original position.

ln the drawings:

FIG. 1 is an elevational view of abrading apparatus embodying the invention, with portions thereof partly in section and partly schematic;

FlG. 2 is an enlarged fragmentary view of a portion of the apparatus in FIG. 1, partly sectioned to show the invention in detail;

FIG. 3 is a horizontal sectional view, taken along line 3-3 of FlG. 2; and

P16. 4 is a view of selected elements from FIG. 3, with the cam repositioned for transmitting a camming force in a direction opposite to that of FIG. 3.

Shown in FIG. 1 is abrading apparatus of the general type described in the following US. Pat. Nos. 3,344,524; 3,516,204; 3,534,503; and 3,551,807, the disclosures of which are incorporated by reference herein.

The abrading apparatus 10 comprises a housing 12 mounted on a base 13 and enclosing a hydraulic cylinder 14 in which a double-acting piston 16 reciprocates in horizontal direction, thereby moving the driving member or piston rod 18 in opposite directions normal to the front vertical wall 20 of the housing. Pressurized hydraulic fluid from a chamber 22 flows through suitable conduits under control of a valve 24 to the interior of cylinder 14 for alternately pres surizing one face and then the other face of piston 16 to move it and the rod 18 in desired direction, while residual fluid in the opposite end of the cylinder is driven by the piston back through other conduits toward the chamber 22.

Also mounted on the base 13 is a workpiece support 26 including a holder 28 for a workpiece 30. The latter, as indicated previously, may be a non-conductive substrate having parallel conductors with printed material on the substrate bridging the conductors, all of which is well known in the art as represented by the cited patents. (See FIG. 2 ofU.S. Pat. No. 3,534,503). It will suffice to say that the electrical value of the electrical element bridging the conductors may be adjusted or trimmed by abrading it with an airborne stream of abrasive powder supplied by a flexible hose 32 through a tubular nozzle holder 33 to a nozzle 34. The nozzle 34 directs the abrasive jet at a selected spot on the workpiece 30, and it is moved along the workpiece by means to be described hereinafter. A tubular connector 35 secures the hose 32 to the holder 33.

An exhaust hood 36 surrounds the nozzle 34 and directs inflowing air with entrained particles of spent abrasive material into and through an exhaust duct 38 for discharge.

Unlike conventional abrading apparatus wherein the nozzle holder 33 is attached by a bracket directly to the outer end of the piston rod 18, the present abrading apparatus has the nozzle holder attached to a bracket 40 of a motion translating device 42. A set screw 43 secures the nozzle holder 33 to the bracket 40 in selected vertical position. As best seen in FIG. 2, the device 42 includes a right angle support member 44 comprising a vertical portion 46, a horizontal portion 58, and the bracket 40 connected to the free end of portion 58. The vertical portion 46 of member 44 is apertured and vertically slit to the lower edge for receiving a stationary collar 48. The collar 48, which slidably receives the rod 18, is rigidly mounted on the front wall 20 of the housing 12; and the support member 44 may be firmly clamped on the collar by means of a screw 50 for drawing together the bifurcated lower ends of portion 46. However, the support member 44 may be secured to the housing 12 by any suitable means.

The bracket 40 is connected to the support member 44 through a slide 52 and guide block 54 assembly. This assembly is disposed in a downwardly opening cavity 56 formed at the outer end of the horizontal per tion 58 of the support member 44. The guide block 54 is fixedly secured to the horizontal portion 58 of member 44 by screws 60, and it is provided with a. groove for slidably receiving an elongated track 62 on the upper surface of the slide 52. The illustrated dovetail crosssectional configuration of the track 62 and suitable clearances between it and the lubricated groove surfaces ensures retention and smooth sliding motion of the assembly. The use of roller bearings at these sliding surfaces is optional.

The length of the slide 52, shown in FIGS. 2, 3 and 4, is less than than of the cavity 56 by the amount of travel to be allowed it and the nozzle 34 carried thereby. The nozzle 34 is movable with the slide 52 because the bracket 40 carrying the nozzle holder is secured to the slide 52 by means of threaded stud 64 received in a threaded hole 65. The outer end of the stud 64 has an enlarged head portion disposed within a recess of the bracket 40, and a roller 66 is mounted thereon for free pivotal movement on a vertical axis. With this construction and arrangement, any force applied to the roller 66 having a component in the longitudinal direction of the track 62 will tend to move the slide 52, the bracket 40, the nozzle holder 33 and the nozzle 34 in horizontal direction parallel to the front wall of the housing 12.

Movement of the slide 52 is yieldably resisted by a coil spring 68 of the compression type, one end of which is received in a longitudinal bore 70 in the slide 52, and the other end of which is retained by a pin 72 extending into the cavity 56 from a screw 74. The position of the screw 74 may be threadedly adjusted for varying the compressible length and therefore the resistance of the spring 68. As shown in FIG. 2, a felt gasket 76 is interposed between the wall structure of the member 44 surrounding the cavity 56 and the bracket 40 in order to seal the parts therein from stray abrasive material, and yet permit free sliding motion of the bracket.

Camming force is applied to the roller 66 by a cam 78. The cam 78 is received in a groove or socket in the rod 18, and secured therein as by a screw 80 through slot 81, in the manner illustrated. The cam 78 has two

camming surfaces

82, 84, one of which at a time is engageable with the roller 66. As illustrated in FIG. 3, the cam 78 is shifted to one side of the axis of rod 18 so that surface 82 will remain in contact with the roller 66 throughout the stroke of rod 18 in the direction of arrow 86. The stroke of rod 18 can be seen in FIG. 2 where the rod 18 is shown in solid lines at the beginning of a forward stroke, and in broken lines at the end of such stroke. The arrow 88 in FIG. 3 designates the direction in which the slide 62 is moved by the camming action when the parts are so positioned. The numeral 90 designates an additional threaded hole capable of receiving and retaining the stud 64.

When it is desired to move the slide 62 by camming action in the direction of arrow 92, opposite to the direction of arrow 88, minor changes are required. (See FIG. 4). The stud 64 is moved from hole 65 to hole 90, thus repositioning roller 66. The spring 68 is moved from bore 70 to bore 94 and the screw 74 with its pin 72 is also moved to the opposite side of the member 44. Finally, the screw 80 is loosened to permit cam 78 to be shifted into position where camming surface 84 will engage repositioned roller 66 throughout the forward stroke of rod 18 in the direction of arrow 86, and screw 80 is then retightened. The slot 81 is elongated in transverse direction, sufficient to permit rapid and convenient shifting of cam 78 from one position to another.

The extent of linear traverse of the rod 18 and the nozzle 34 is controlled by valve 24 which regulates the timing and duration of the pressurization of the cylinder 14 on each side of the piston 16. It can be seen, however, that a piston stroke in the direction of arrow 86, is employed for moving the slide 62 and the nozzle 34 carried thereby in either of the transverse directions indicated by

arrows

88 and 92. This new versatility of the abrading apparatus, as accomplished by the invention, permits a number of them to be arranged side by side for operation on workpieces 30 carried sequentially to a work station in front of each apparatus on a conveyor belt serving as a workpiece holder 28. A substrate or workpiece 30 may be trimmed at one or more stations by a nozzle 34 moving conventionally in direction 86, and then at another station by a nozzle 34 moving in

direction

88 or 92 by means of the device 42. On the other hand, a workpiece 30 may remain fixed by its holder 28, and be trimmed with a nozzle 34 moved in several directions by use of the device 42.

Optionally, the bracket 40 may be removed from slide 52 and suitably connected, e.g., bolt 80, directly to the rod 18 in place of the cam 78 for movement with the rod 18 in the direction of arrow 86. The inexpensive provision for optional convertibility for reciprocating nozzle movement in either one of

directions

86 or 88 is a feature of the present invention.

It is to be noted that the workpiece support 26 and holder 28 are not free to rotate about a vertical axis. A rotatable workpiece support or holder is not necessary to reposition the workpiece 30 relative to the path of movement of the nozzle 34 when it is desired to abrade, for example, along paths that are at right angles to one another on the surface of a workpiece. Rather, the nozzle 34 is movable in a plurality of paths with respect to a fixed workpiece 30.

The nozzle 34 is carried for reciprocative movement in a first horizontal direction by means of an assembly including the slide 52, the guide block 54, the support member 44 and the bracket 40. The annular surface of the roller 66, which is formed about the upright pivotal axis of the roller, defines the cam follower surface to which a driving force is transmitted by the cam 78.

The cam 78 is driven into engagement with the roller 66 directly by a hydraulically actuated piston 16 and rod 18 assembly serving as driving means, reciprocatively movable in a second horizontal direction, and preferably disposed at a right angular inclination to the path of movement of the nozzle carrying means. After loosening the screw 80, cam 78 may be shifted horizontally in first direction, so that either one of the convergent and oppositely facing camming surfaces 82 and 84 is selectively positionable to engage the cam follower surface of the roller 66. The nozzle carrying means is thus driven transversely to the direction of the driving force.

it is the function of the coil spring 68 to yieldably rcsist movement of the slide 52 of the nozzle carrying means during displacement. After displacement of the slide 52 and withdrawal of the camming force, the spring 68 biases the slide back to original position.

The workpiece holder 28 is positioned generally below, or beneath, the intersection of a line extending in first direction through the roller 66 and a line extending in second direction through the cam 78. Between such intersection and the workpiece holder, surrounding the adjacent nozzle 34, is positioned the exhaust hood 36 or inlet of the exhaust system. It is a feature of the invention that spent abrasive particles are unlikely to enter between the movingsurfaces of the elevated nozzle carrying means and cause premature wear, because the exhaust inlet is in position to intercept particles which rebound from the workpiece 30.

We claim: 1. Abrading apparatus comprising: a nozzle, means supplying a high velocity stream of abrasive particles to said nozzle, means carrying said nozzle for movement therewith in a first direction and having a cam follower surface thereon, driving means movable in a second direction which is angularly inclined to said first direction and having a cam connected thereto positioned to engage said follower surface and thereby drive said nozzle and carrying means in said first direction.

2. Abrading apparatus according to claim 1 wherein said cam is removable from said driving means, and said nozzle is removable from said carrying means and adapted to be carried by said driving means for movement therewith in second direction, whereby said nozzle is optionally movable in said first direction or said second direction.

3. Abrading apparatus according to claim 2 further including a holder for a workpiece to be abraded by said apparatus, said holder being generally positioned below the intersection of a first line extending in said first direction through said cam follower surface and a second line extending in said second direction through said cam.

4. Abrading apparatus according to claim 3 further including exhaust means adjacent said nozzle, vertically positioned above said workpiece holder and below said intersection, adapted to entrain and remove particles of spent abrasive material and thereby minimize the risk of such spent material contacting the carrying means positioned thereabove.

5. Abrading apparatus according to claim 3 wherein said holder is fixedly secured against rotation about a vertical axis.

6. Abrading apparatus according to claim 1 wherein each of said driving means and said carrying means is reciprocative, and further including biasing means yieldably resisting motion of said carrying means in said first direction and biasing said carrying means opposite to said first direction for moving said carrying means back to original position after being driven therefrom.

7. Abrading apparatus according to claim 1 wherein said carrying means includes a roller pivotally mounted thereon, the annular surface of said roller defining said cam follower surface.

8. Abrading apparatus according to claim 7 wherein said cam is provided with a plurality of camming surfaces, one of which at a time is engageable with said follower surface, and means shiftably mounting said cam on said driving means whereby said cam is positionable for engagement with said follower surface by a selected one of its camming surfaces.

9. Abrading apparatus according to claim 8 wherein said first and second directions are in generally horizontal planes, said roller pivots on an upright axis, sai follower surface is disposed about said upright axis, said cam is shiftable generally in first direction, and said camming surfaces face in generally opposite horizontal directions.

10. Abrading apparatus according to claim 9 wherein said camming surfaces are disposed in convergent relationship.

Claims

1. Abrading apparatus comprising: a nozzle, means supplying a high velocity stream of abrasive particles to said nozzle, means carrying said nozzle for movement therewith in a first direction and having a cam follower surface thereon, driving means movable in a second direction which is angularly inclined to said first direction and having a cam connected thereto positioned to engage said follower surface and thereby drive said nozzle and carrying means in said first direction.

9. Abrading apparatus according to claim 8 wherein said first and second directions are in generally horizontal planes, said roller pivots on an upright axis, said follower surface is disposed about said upright axis, said cam is shiftable generally in first direction, and said camming surfaces face in generally opposite horizontal directions.