US 3254454 A
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June 7, 966 D. L. CETRANGOLO 3,254,454
AUTOMATIC SURFACE TREATING MACHINE Filed Feb. 24, 1964 5 Sheets-Sheet 1 Wfir ATTORNEY June 7, 1966 D. L. CETRANGOLO 3,254,454
AUTOMATIC SURFACE TREATING MACHINE 5 Sheets-Sheet 2 Filed Feb. 24, 1964 FIG. 4
INVENTOR u DOLIVIO L. CETRANGOLO FIG. IO
J1me 1966 D. 1.. CETRANGOLO 3,254,454
AUTOMATIC SURFACE TREATING MAQHINE Filed Feb. 24, 1964 5 Sheets-Sheet 3 DOLIVIO L.CETRANGOLO United States Patent Office 3,254,454 AUTOMATIC SURFACE TREATING MACHINE Dolivio L. Cetrangolo, E. Roxbury Road, Northfield, Vt. Filed Feb. 24, 1964, Ser. No. 346,927 Claims. (Cl. 51-56) This invention relates to the finishing and polishing of the surface of objects of various kinds including of stone where substantial labor and skill is involved, as well as to a machine by which the final finishing and polishing operations are performed.
The invention relates particularly to a machine having an abrading head or work unit'of a character to be moved over the surface of stone or other hard surfaced objects to be finished and polished, and which machine ordinarily is hand operated by a workman to finish and polish the surface and edges of an object regardless of whether flat, contoured, serpentine or oval.
After a slab of stone such as marble, granite or the like has been sawed or otherwise reduced to desired size, it is necessary to smooth and polish the slab to provide a finished product. The procedure has been to go over the stone with a relatively thick coarse grinding wheel to remove the high spots on the stone. Then a thinner flexible 7 wheel has been used in the presence of an abrasive which normally is suspended in a fluid such as water, or the like. When all of the marks have been removed, the stone is then polished by a felt buffer to bring out the natural beauty of the stone.
Heretofore, the finishing of the stone has been a laborious task in which it hasbeen necessary for an operator to control the movement of the grinding and polishing wheels. This has required the undivided attention of the operator to finish one stone at a time and has resulted in fatigue on the part of the operator and lack of uniformity in the finished product, as well as limiting the output of the operator.
It is an object of the invention to provide a fully automatic machine for performing the finishing and polishing operations on relatively hard surfaces, including objects which have coarse surfaces, as well as those having finer surfaces, and which machine can be given a definite predetermined setting and allowed to operate automatically with only a single work-man attending a number of machinesto obtain readily, satisfactorily and expeditiously a surface of uniformly high quality at substantially lower cost, in a comparatively short time with little fatigue to the attendant.
.Another object of the invention is to provide a machine which can be easily and quickly adjusted while in operation without loss of time, and which will pause for a predetermined and variable length of time at each edge or limit of the surface of the work where it is most necessary to give greater time than in the center of the surface being finished.
Other objects and advantages of the invention will be apparent from the following description taken in conjunction with the accompanying drawings in which:
FIG. 1 is a perspective illustrating one application of the invention;
FIG. 2, a rear elevation thereof;
FIG. 3, an enlarged transverse section on the line 33 v FIG. 9, an enlarged fragmentary detail section on the line 9-9 of FIG. 1;
FIG. 10, a fragmentary detail elevation illustrating one of the adjustable projections or stops;
FIG. 11, a transverse section on the line 11 11 of FIG. 10;
FIG. 12, a rear elevation of a modified form of the invention; 7
FIG. 13, an enlarged perspective of the driving mechanism of FIG. 12;
FIG. 14, a section similar to FIG. 3 of the modified device of FIG. 12;
FIG. 15, a vertical section on the line 15--15 of FIG. 14;
FIG. 16, a perspective of a modified drive means for the grinding and polishing wheel; and v FIG. 17, a perspective of a further modified form of drive means for the grinding and polishing wheel.
Briefly stated the finishing and polishing machine of the present invention is composed of three basic parts, including: First, a tank in which the stone or other hard surfaced object is received and supported in the presence of water or other fluid; second, a grinding unit with means for supporting it for raising and lowering movement and, third, means for guiding the movement of the grinding unit in two generally horizontal directions, one at right angles to the other. I a
With continued reference to the drawings, a tank 10 of any desired material is provided for containing water, light oil, or other fluid. A block of stone or other object 11, having a rough surface and rough edges is adapted to be received in said tank to be finished and polished to sired character, such as with concentric rings or the like is mounted by brackets 13 on a shaft 14 journaled in suitable bearings (not shown) in a housing 15.
On the shaft 14 is a multiple grooved pulley 16 driven from a motor 17 through a pulley 18 on the motor shaft and by means of belts 19 driving the pulley 16 and the shaft 14 of the floating abrading or grinding head or unit. In finishing and polishing the relatively hard surface of a stone or other object, it is necessary that the polishing wheel be moved over the entire surface including the edges where it is necessary to be retained for a longer period of time than over the intermediate area due to the fact that the diameter of the abrading unit is in contact with the intermediate portion for a longer period of time. The grinding and polishing or abrading unit is of the floating head type and is provided with a yoke 20 attached to the housing 15 and connected by a ball and socket coupling 21 and a tightening screw 22 to a shaft 23. The shaft 23 extends through a fitting 24 and is attached to a platform 25 which in turn is connected to a sleeve 26 slidable on a pipe or tubular member 27 mounted on end posts 28. The ends of the tube 27 are provided-'with spaced vertical bars 29 having axles 30 carrying sprockets 31 over which is mounted a chain 32 having upper and lower horizontal runs, the upper central portion of the chain being located around idler sprockets 33 mounted on a support 34 fixed to the sleeve 26.
The chain 32 extends between the idler sprockets 33 and over a drive sprocket 35 mounted on the output shaft 36 of a gear box 37. Such gear box is driven by a pulley 38 by means of a belt 39 and a drive pulley 40 mounted on the shaft of a motor 41. The motor 41 is a threephase reversible motor in order to produce the necessary reciprocation of the abrading head. A pair of stops 42 are adjustably mounted in a predetermined position on the chain 32, the adjustability making it possible to regulate the amount of delay when the direction of movement of the grinding wheel is reversed.
Patented June 7, 1966- As the sprocket 35 rotates the chain 32 will move through openings 43 in the posts 28 until one of the adjustable stops 42 engages one of the posts, for example, the post 28 at the right in FIG. 2. The continued operation of the sprocket 35 by the motor 31 will cause the sleeve 26 and entire platform 25 with its contents to move along the tubular member 27 until one of a pair of limit switches 26', carried one on each end of the sleeve 26, engages one of a pair of projections 44 mounted on sleeves 44 adjustably secured to opposite ends of the tube 27. The closing of either of the switches 26' causes the motor 41 to reverse itself and the platform 25 and the grinding head carried with it will remain stationary until the chain has had time to travel in the opposite direction until the other stop 42 engages the opposite post 28. The sleeves 44 are adjustable to increase the flexibility of operation and normally are spaced apart a distance generally equal to the length ofthe stone so that the working head will remain on the surface it is polishing.
A second motor 45 is mounted on the platform 25 and is adapted to drive a gear box 46 having a projecting shaft 47 on which is fixed a crank arm 48 with a slot 49 receiving a pivot point or pin 50 and by which a connecting rod 51 is a reciprocated. The connecting rod 51 has its remote end connected to a pivot 52, mounted on a bracket 53, fixed to the reciprocating round rod or shaft 23 which extends through the fitting 24.
The motor 45 causes rotation of the crank arm 48 to produce reciprocation of the bracket 53 and the shaft 23 causing the finishing and polishing unit to move transversely of the stone or other hard surfaced object upon which work is being performed so that in effect there is a lengthwise and transverse movement of the polishing unit.
The shaft 23 travels a limited amount transversely and the platform 25 and sleeve 26 travel lengthwise of the object upon which work is being performed. The amount of reciprocation of the shaft 23 can be adjusted between certain limits by adjusting the pivot 50 in the slot 49 of the crank arm 48.
The invention is of such a character that work of various lengths and breadths, from a very few inches to several feet, can be treated. Differences in the width of the work handled is accommodated by the size of the abrasive wheels and the setting of the same for motion in regard to the slab being treated. The amount of movement of the end of the connecting rod is dependent upon the location of the crankshaft pivot point 50. If a small stone is to be polished, an abrasive wheel of a diameter to cover the stone can be provided and the pivoted connection of i the connection rod will be located as close to the pivot point of the crank arm as possible to provide minimum motion of the shaft 23.
Treatment of a curved surface presents no problem due to the fact that the surfaces of the members 27 and 26 are circular. This allows the ball and socket coupling 21 to permit the operating head to follow the contour of the surface against which it is operating. The motor 41 and gear box 37 are adapted to move the sleeve 26 along the tubular member 27 at a relatively slow rate of speed while the motor 45 and gear box 46 with the crank arm 48 will move the shaft 23 and the abrading or polishing head at a more rapid rate of speed. This causes the abrading head to move back and forth across the stone many times during each traverse of the length of the stone. In view of the operation of the unit in its association with the chain 32 and the stops and limit switches, grinding action at the opposite ends of the stone will be accomplished with the grinding head moving transversely while there is no longitudinal movement. Consequently the ends will receive a greater amount of treatment than the mid-portion which is desirable. Due to the limits of the throw of the crank there also will be a pause of the work unit at opposite ends of its path of travel because the work head moves faster across the mid-portion of the work than at the edges.
The inner end of the connecting rod 51 and the crank 48 in motion describe the circumference of a circle and travel at a constant rate of speed. Therefore, the speed of the connecting rod 51 is greater during the middle of the stroke than it is at each end, decreasing in rate of speed until eventually it stops and reverses direction with gradually accelerating speed as it travels toward the middle of the stroke.
The pivotal mounting of the platform 25 on the tube .27 permits raising and lowering of the work head affording access to the work area and the insertion and removal of a stone or other object from the tank 10. Raising of the work head is facilitated by means of a post 55 rotatably mounted on a base 56. The post 55 may be an I-beam or of other construction, about which is mounted a pair of spaced yokes or coupling members 57 having rollers 58 disposed on one side of the post and rollers 59 supported by brackets 59' carried by the yokes 57 on the opposite side of such post. The rollers 58 and 59 bear against opposite surfaces of the post to reduce friction and permit ready raising and lowering of the couplings. An arm or bracket 60 attaches to the upper coupling member 57 and has pivoted to its outer end a depending rod or bar 61 having its lower end pivoted to a yoke 62 having diverging legs 63 fixed to the housing 15. Beyond its center the arm or bracket 60 is supported by a bracket or brace 64, the lower end of which attaches to the lower connector 57. The rollers 59 are mounted in upright brackets 59' so that they are spaced above the brackets 60 and 64 to maintain a firmer relation with the post 55 on which the assembly is mounted.
In order to raise the arm 60 and the depending bar 61 carried by it, a platform 65 is provided having one end attached to the brace 64 and the other end attached to a brace 66 mounted on lower bracket 59'. On the platform 65 is mounted a motor 67 on the shaft of which is a pulley 68 which drives a gear box 70 by means of a belt 69. A sprocket 7 1 is fixed to the output shaft of the gear box 70 and drives a chain 72 and a second sprocket 73 which in turn drives a pinion 74 engaging a rack 75 attached to the post 55. The operation of the motor 67 which causes the pinion to travel along the rack may be controlled from a suitable control panel (not shown).
With reference to FIGS. 1215 a modified form of the invention is disclosed which is used primarily in the bufiing or polishing process although it could be used in the grinding process. In this modification the vertical bars 29 and sprockets 31 are removed from one end of the device and are replaced by a single relatively large sprocket mounted on a shaft 81 rotatably journaled in bearings 82 carried by a platform 83 fixed to one of the upright posts 28. The sprocket 80 is adapted to receive the chain 32 and to drive such chain and the sleeve 26 along the tubular member 27. The sprocket 80 .has a plurality of openings 84 in which a pair of pegs 85 and 86 are selectively mounted. In order to drive sprocket 80 a motor 87 is mounted on a platform 88 and is adapted to drive a gear reduction 89 having output shaft 90 located substantially along the same axis as the shaft 81. The free end of the output shaft 90 is provided with an arm 91 substantially at right angles thereto and such arm is of a length to engage the pegs85 and 86. The gear reduction 89 rotates the output shaft 90 at a slow rate of speed for a purpose which will be hereinafter described.
The crank arm 48 is provided with a cam 94 projecting inwardly toward the gear box 46 and located on the opposite side of the shaft 47 from the slot 49. When the crank arm is rotated to advance or retract the shaft 23, the cam 94 will engage microswitches 95 and 96 mounted on the gear box 46. The microswitches 95 and 96 are located in a position such that the cam 94 will engage one of the switches as the shaft 23 approaches the outermost limit or throw and will engage the other micro.
' be advanced a short distance more rapidly than normal when one of the switches is closed and will be moved in the opposite direction counter to the movement of chain 32 when the other microswitch is closed. The movement of the polishing head will form substantially a plur-ality of spaced parallelograms due to the fact that the sprocket 80 is moving the chain and the sleeve 26 at a very slow rate of speed in one direction while simultaneously the motor 45 is extending and retracting the shaft 23 back and forth across the stone being polished and as the polishing head approaches one side of the stone the motor 41 is operated in one direction to advance the sleeve in the same direction as the chain is moving, and is operated in the opposite direction at the other side of the stone to move the sleeve in reverse direction counter to the movement of the chain.
In order to reverse the direction of travel of the sleeve 26 after it has travelled the length of the stone, a limit switch 97 is mounted on each of the posts 28 in a position to be engaged by one of the stops 42. Such limit switches are adapted to reverse the motor 87 to move the chain in the opposite direction. Since the ends of the stone do not have the benefit of the full width of the polishing wheel, it is desirable to incorporate a delay in the machine so that the polishing wheel will move back and forth across the ends of the stone without any longitudinal movement. This is accomplished by locating the pegs 85 and 86 in any desired opening 84 so that when the motor is reversed the arm 91 will move away from the peg which it had been engaging and will operate freely until it engages the other peg whereupon the sprocket 80 will be operated in the reverse direction.
If desired, the pegs 85 and 86 may be removed from the sprocket 80 and the sleeve 26 may be moved along the tubular member 27 by the motor 41 as described in the first modification during the grinding process. During the polishing or buffing process the procedure of the second modification may be followed to impart the most desirable pattern of movement to the grinding or polishing wheel.
As illustrated in FIGS. 16 and 17 the grinding or polishing wheel 12 may be rotated by a self-contained unit attached to the structure which moves along the length of the stone. In FIG. 16 such wheel is connected by brackets 100 to a yoke 101 fixed to a shaft 102 and directly driven by a motor and gear reduction 103. The motor and gear reduction are secured to the bracket 53 at the outer end of the shaft 23 and are supported by the grinding or polishing wheel which engages the stone.
In FIG. 17 a drive motor 105 is mounted on a bracket 106 depending from the inner end of the shaft 23 and such motor drives a multiple sheave pulley 107 which in turn drives a multiple sheave pulley 108 by belts 109. The driven pulley 108 is fixed to a shaft 110 journaled in bearings 111 mounted on the brackets 53 on the outer end of the shaft 23. A grinding or polishing wheel is adapted to be fixed to the lower end of the shaft 110 in any desired manner.
It will be apparent from the foregoing that an automatic surface-treating machine is provided in which the work unit is mounted so that it may be located in a position to allow access to the work area, and also it is mounted for movement crosswise and lengthwise of the surface being treated and caused to pause at the limit of each movement, resulting in edge treatment greater than the intermediate portion of the object, the construction and arrangement making it possible for a number of machines to be attended by one workman.
It will be obvious to one skilled in the art that various changes may be made in the invention without departing from the spirit and scope thereof and therefore the invention is not limited by that which is illustrated in the drawings and described in the specification, but only as indicated in the accompanying claims.
What is claimed is:
1. An automatic surface-treating machine comprising a work head, mounting means for said work head comprising a first tubular shaft connected by a universal joint to received within one of said sleeves, a second tubular shaft extending through the other of said sleeves, spaced posts supporting said second shaft, sprockets at the opposite ends of said second shaft, a chain mounted on said sprockets and extending through said posts, spaced adjustable projections on said chain for engaging said posts, gearing carried by said platform and engaging said chain, a reversible motor on said platform connected to drive said gearing and move said platform and work headalong the work, control means for reversing said motor when the work head reaches the end of the work, a second motor mounted on said platform, a crank having a connection with the shaft of said motor, a connecting rod having one end adjustable relative to said crank, a bracket connecting the otherend of said connecting rod to said first tubular shaft whereby upon operation of said crank by said second motor said connecting rod and first shaft will be reciprocated relative to said platform.
2. A polishing unit of the floating head type, comprising a work head, a shaft having a ball and socket connection with said unit, a fitting receiving said shaft, a platform attached to said fitting, a sleeve attached to the side of said platform at right angles to said fitting, a tubular member received in said sleeve, posts mounting said tubular member, sprocketed spaced end bars carried by said tubular member, a chain extending around said sprocketed end bars, gearing engaging said chain for moving saidplatform and work head, a reversing motor on said platform connected to drive said gearing, means for reversing said motor, spaced stops adjustably mounted on said chain allowing said motor to move said chain until one of said stops strikes an obstruction and upon con- 3. The structure of claim 2 in which said means for producing recpirocation includes a second motor mounted on said platform, a crank arm driven by said motor, and a connecting rod and a bracket attached to said shaft for causing reciprocation thereof. I
4. The structure of claim 2 and means for supporting said work head comprising an upright bar, a horizontal bar mounting said upright bar, a post, means mounting said horizontal bar for vertical adjustment on said post, and means for raising and lowering said horizontal bar on said post.
5. A machine for polishing the surface of objects, including stone, comprising a tank for containing a fluid and a stone or other object to be polished, a work head of a character to be moved over the surface of the stone, and mounting means for said work head, said mounting means comprising a first shaft having a universal connection with said work head, a support having a sliding moving said first shaft relative to said support, means for reversing said driving means, and means providing a delay in the movement of said work head when said driving means is reversed, whereby said work head may be moved in a generally horizontal plane in two directions with a pause at the limit of each movement.
6. The structure of claim 5, and means whereby said work head may be supported in lowered operative position or in elevated position to allow access to the work area into and from a position to be operated upon by said work head.
7. The structure of claim 5, and means for supporting said work head for elevational adjustment.
8. An automatic surface treating machine comprising a work unit, means for supporting and driving said work unit, means automatically for moving said work unit over the surface of an object to be treated including a support disposed along one side 'of the object, a sleeve slidably mounted on said support, a platform fixed to said sleeve, chain means having lost motion means carried by said support, a first reversible drive means mounted on said platform and engageable with said chain means for moving said platform along said support, a shaft slidably mounted on said platform and being reciprocable in a direction generally normal to the direction of movement of said sleeve, a second drive means mounted on said platform and having a crank arm, and a connecting rod pivotally connected at one end to said crank arm and pivotally connected at the opposite end to said shaft.
9. The structure of claim 8 including a third drive means mounted on said support and engageable with said chain means, and means for driving said first drive means intermittently in opposite directions;
10. A surface treating machine comprising an elongated member, a platform slidably and rotatably mounted on said elongated member, a first drive means for moving said platform along said elongated member, means for reversing said first drive means, means providing a delay in the movement of said platform when said first drive means is reversed, shaft means slidably mounted on said platform at an angle to the longitudinal axis of said elongated member, a tool carried by said shaft means, a second drive means for moving said shaft means relative to said platform, means for reversing the direction of movement of said shaft means, means providing a pause when the direction of movement of said shaft means is reversed, and said first drive means and said second drive means being operated simultaneously or independently, whereby said tool may be moved in multiple directions with a pause at the end of travel in each direction.
References Cited by the Examiner UNITED STATES PATENTS 1,914,413 6/1933 Elbert 5l35 2,694,274 11/ 1954 McGibbon 51-35 2,924,768 2/1960 Ferrand et al. 318-480 3,026,653 3/1962 Zordo 5l177 ROBERT C. RIORDON, Primary Examiner.
J. A. MATHEWS, Assistant Examiner.