Patent GB-724887-A (GB)
Title: Improvements in abrasive finishing methods and mechanism therefor
IPC: B24B21/02
Filed: 1953-10-12
Abstract: 724,887. Grinding and polishing rods &c. AUTOYRE CO. Oct. 12, 1953 [March 31, 1953], No. 27932/53. Class 60 [Also in Group XXII]. The surface of a rod or tube is finished by an abrasive tape or a carrier tape for abrasive maintained under tension, a portion of the tape which is looped around the rod being reciprocated; the tape may be fed. A finishing machine comprises a base 4 to which are welded uprights 5 connected by longitudinal members 6 and cross members 7 welded thereto. A slotted bracket 8 is mounted at the centre of each cross member 7 and slotted brackets 9 aligned thereto are mounted on the upper ends of uprights 5. A circular support 10 is mounted in each set of slotted' brackets, being rotatably adjusted and locked in adjusted position by set screws 11. Each support 10 has a central aperture 12 through which a work piece 13 may be threaded and moved longitudinally through the machine. The rod 13 to be finished is carried by a supply reel 14 and is drawn continuously through the machine by a bull block reel 16 driven by motor 17; if it is desired to form the finished rod into wire of different shape immediately following the finishing operation, the rod may be threaded directly from the machine to a rolling mill which would replace the bull block and draw the rod through the machine. A draw die assembly 18 is mounted on a cross bar 18a welded to the ends of frame members 6. The draw die assembly may comprise two dies arranged in close succession so that work hardening is reduced to a minimum, thus facilitating the removal of surface imperfections by the machine. The draw die assembly may be replacedby roll type straightener assembly comprising horizontal rolls 25 and vertical rolls 26 all mounted on a bracket 27 adapted to be mounted on the cross bar 18a. Each of the supports 10 has a pair of oscillatable bell cranks 19, 20 rotatably mounted thereon and provided at their adjacent ends with tape actuating members or guide rolls 21, 22. Abrasive tapes 23 pass over each set of guide rolls and around the rod to form U-shaped loops. There are twelve circular supports 10 arranged in three groups of four. the first group have relatively coarse abrasive tape, tape of finer grit being used in the succeeding groups. In order to subject the entire circumference of the rod to the action of the abrasive tapes, the supports 10 are so positioned in each group that succeeding tape loops are spaced angularly 90 degrees apart from each other about the axis of the rod. Alternatively, each group may have three supports with 120 degrees angular spacing, or six supports with 60 degrees angular spacing. An abrasive tape supply reel 49 is rotatably mounted on a shaft 50 carried by support 10, its rotation being frictionally retarded by washer 51, spring 52, washer 53 and nut 54 which press the reel into engagement with boss 55 on support 10. The tape then passes through a brake mechanism comprising a pair of parallel flat links 57 provided with slots 58 and held together at their lower ends by a shaft 59 on which is rotatably mounted a brake roller 60 serving as a spacer for the links. The links are pressed into frictional engagement with the ends of the roller 60 by spring 61, washer 62 and nut 63 on the outer end of the shaft, adjustment of the nut varying the friction between the roller and links. A second brake roller 64 positioned between the links has a shaft 65 slidably and rotatably mounted in the link slots 58; a rectangular section stud 46 carried by support 10 passes through the slots at their upper ends, so as to support the brake assembly loosely against rotation while permitting it to align itself with the tape. The bell cranks 19, 20 each comprise a pair of triangular side plate members interconnected by a strut. Bell crank 19 is rotatably mounted on a shaft 70 extending between support 10 and auxiliary bracket 71 carried thereby and spaced therefrom; the horizontally extending portion 74 has a shaft extending between the side plates at the outer end thereof. Flanged tape guide rollers 76, 21 are rotatably mounted on shafts 70, 75 between the side plates. Bell crank 20 is rotatably mounted on feed drive shaft 77 which is mounted for rotation in support 10 and bracket 71; the horizontally extending portion 79 has a shaft 80 at its outer end on which the flanged tape guide roll 22 is rotatably mounted. The upwardly extending portions of the bell cranks 19, 20 are connected by a rod 81 so that the guide rolls 21, 22 move bodily in opposite directions; the tape is thus reciprocated over the rod surface when the bell cranks are oscillated on their axes. The oscillation is effected by a motor 82 mounted on the back of the support 10 driving a shaft 84 having a crank-pin 85 connected with the upwardly extending portion of the bell crank 20 by a connecting rod 86. Feed mechanism for the tape includes a flanged feed roll 87 mounted on shaft 77 and driven thereby through pin 88. An unflanged feed roll 89 is mounted on a shaft 90 rotatably mounted in the upper end of a forked swinging bracket 91 rotatably mounted at its lower end on a shaft 92 secured to support 10. A spring 98 connected between a pin 100 on bracket 71 and a pin 99 on the swinging bracket 91 biases the bracket 91 in a counterclockwise direction about shaft 92 to urge roller 89 against roller 87. The roll 89 is driven by shaft 90 through a drive pin 95, the shaft being driven through identical gears 96, 97 keyed to shaft 77, 90, the teeth of the gears being so shaped and meshed as to permit the roller 89 to engage the surface of flanged roller 87. Shaft 77 is driven by motor 82 through pulley 101, belt 102, pulley 103, reduction gear 104, shaft 105 and coupling 106. Rod guide rolls 107, 108 are provided on the support 10 on either side of the tape loop to maintain the rod straight while it is acted on by the tape; the rolls are V-grooved, roll 107 is mounted on shaft 109 carried by brackets 110 and roll 108 is mounted on shaft 111 carried by brackets 112. For different size rods the brackets 110, 112 are adjusted or the guide rails replaced by others of appropriate size. Auxiliary guide means such as roll 113 and trough 114 are provided to guide the used tape to a suitable bin in different angular positions of the supports. As soon as one coil of rod is nearly exhausted, the end of another coil is welded to the trailing end of the first coil, the joint is ground down as needed and the second coil is fed into the machine.  As the reels of tape become exhausted, the ends of other reels may be adhesively or otherwise secured to the trailing ends of the exhausted reels without interrupting the operation of the machine. Tape feed speeds of 4 inches to 12 inches per minute and rod speeds of 40 to 50 feet per minute may be used.  Instead of a continuous tape feed, an intermittent feed of the ratchet type may be employed. To effect greater tape contact area with the rod for the same tape width, the tape may be led over the rod at angle to the axis thereof.  For polishing, non-abrasive cloth tape is used, polishing compound being applied to the tapes as it passes through the machine.