Patent GB-406940-A (GB)
Title: Improvements in machines for boring and plugging holes in wood
IPC: B27G1/00
Filed: 1933-09-20
Abstract: 406,940. Plugging knot-holes. MAURER, G., 76, Bederstrasse, Zurich, Switzerland. Sept. 20, 1933, No. 25991. Convention date, Sept. 21, 1932. [Class 145 (i).] In a machine for boring and plugging knot holes in wood, two vertically fed slides are disposed side by side over the wood, one carrying a boring tool and the other an annular cutter for producing a plug from a wooden slat arranged above the work, means being provided for depressing the boring tool to bore out a knot, displacing the slides horizontally to position the annular cutter over the knot hole and then depressing the cutter to cut a plug from the slat and insert the previously formed plug into the knot hole. The work is placed on a horizontal table 2, Fig. 3, and the tool slides 6, 7 are fed vertically on a carriage 5 horizontally indexable on guides 4 on an arm 3. The boring spindle 8, Fig. 1, is rotatable in ball bearings 9 in the slide 6 by means of a gear 75 engaging a gear 74, driven by bevel gears from a horizontal shaft 51, the gears 74, 75 being long enough to preserve engagement during reciprocation of the slide. The spindle 22, Fig. 2, carrying the annular cutter 24 for producing the plugs is similarly mounted and driven in the slide 7. A cam shaft 50 is driven by worm gearing and a clutch (not shown), from the shaft 51 and carries a cam 43, Fig. 2, with three rises 44, ... 46 which act through a roller 42 on a lever 41. Telescopic connecting rods 49, yieldable by means of springs 48, connect the lever 41 to a lever 38 acting through a roller 37 on whichever of the slides 6, 7 is placed beneath it to feed the tool therein. Springs return the slides to their inoperative positions. The work is held on the table during operation by means of a presser foot 58, Fig. 1, on the arm 3, containing a rubber block 57 and actuated by a rack and pinion, the pinion being rotated by a yielding telescopic rack-rod 63 reciprocated by a lever 64, 66 and cam 55 on the shaft 50. The slat 83, Fig. 2, from which the plugs are to be cut by the annular cutter 24, is held in a guide 82, adjusted in width by a handle 84, and yieldingly held in the raised position shown by a spring 96 attached to the arm 3. In operation, the work is positioned with a knot below the boring tool 11 and a rod 81 is actuated by hand to engage the clutch driving the cam shaft 50 and simultaneously rock a lever 79 to disengage its end 78 from an aperture 80 in a disc 77 attached to the shaft, thereby allowing the cam shaft to rotate. The cam 55 first rocks the lever 64 to clamp the work by means of the foot 58, after which the rise 44 on the cam 43 depresses the levers 41, 38 to feed the slide 6 together with the boring tool 11 into the work. A lug 20, Fig. 1, on the slide 6 is attached to a spring 17 within a rod 13 vertically movable in the slide and carrying a foot 12, the downward feed of the slide causing the foot 12 to be pressed resiliently against the work. When the desired depth of hole has been bored, the spindle of the roller 37 engages a stop 16 adjustably secured to the rod 13 by nuts 15, whereby the feed of the tool 11 is stopped and any further motion of the lever 41 is taken up in the resilience of the connecting rods 49. When the cam 44 allows the levers 41, 38 to rise, the slide 6 is lifted by its spring and the rod 13 by a spring 14. A cam 54, Figs. 1 and 3, on the shaft 50 then acts on a roller 53 attached to the carriage 5 and indexes the carriage so that the slide 7 comes under the lever 38. During this lateral travel of the carriage, the toothed segment 89, Fig. 2, on the carriage rolls on a fixed rack 90 and causes a pawl therein to rotate a shaft 87 connected by gearing to a roller 85 pressed against the wooden slat 83 from which the plugs are to be cut, thereby feeding the slat forward so that its end abuts a foot 30 on the end of a rod 31. The cam-rise 45 then acts to depress the slide 7 and causes the cutter 24 to cut a plug from the slat, the width of the slat being greater than the internal diameter of the cutter but less than the external diameter so that no waste is produced. A plunger 25 within the spindle 22 is pressed downwards by a spring 29 so that a head 26 thereon is yieldingly held against the plug during cutting, pushing the slat against a previously cut plug x in the foot 30, and pushing the foot against the work. When the plug has been cut, it is held down by the head 26, whilst the slide 7 is raised by the cam portion 45<1> sufficiently for a stop 73, movable laterally in a recess in the slide 7 by a lever and cam 68, Fig. 1, to be placed in the path of a head 27 on the plunger 25, so that on the next downward feed of the slide 7 by the cam-rise 46 the plunger will be locked to the slide and will push the previously formed plug into the work and the newly formed plug into the foot 30, ready for the next knot-hole. Downward feed of the slide 7 is limited by the shaft of the roller 37 engaging a stop 34, adjustably secured by nuts 35 to the rod 31. When the cam 46 passes the roller 42, the stop 73 is returned by springs to allow the plunger 25 to yield again, the slide 7 is raised by its spring and the rod 31 by a spring 32 against a stop 33, the presser foot 58 is raised, and the carriage 5 is returned laterally to its original position by a spring. On completion of a revolution of the cam-shaft 50, the end of the lever 79 drops into the notch 80 of the disc 77, thus stopping the rotation of the cam shaft and allowing the driving clutch therefor to disengage. Cuttings, catching and removing. An air blast supplied by a nozzle 97, Fig. 3, clears dust and shavings away from the tools. Applying glue. Whilst the carriage 5 is moving laterally from the position with the boring slide 6 under the feeding lever 38 to the position with the slide 7 beneath the lever, a jet of glue is squirted automatically into the knot hole from a nozzle 91 provided on a container 92 to coat the bottom and side walls of the hole with glue.