Improvements in the Manufacture of Sound-boards for Pianofortes.

摘要

21,389. Allen, R. B. Sept. 19. Making pianoforte soundboards. - Relates to a machine for cutting bridge - pieces to the required height after thev have been secured to pianoforte soundboards. A belt-driven cutter-spindle vertically slidable in a bracket 2 secured to a wall or standard is attached bv a collar 7 and studs 8 to a counterbalanced operating-lever 5. The studs 8 are connected by cranked links 12 to a block 13 supporting an internally-threaded sleeve 14 provided with a flange 15 at its upper end and a ring 16 at its lower end secured by a screw 17. The sleeve 14 can be adjusted by a milled disk 18 on a screw 19, which slides in a guide 22 carried by a lug 23 on the bracket 2 and is prevented from rotating by a fork 25 engaging the guide 22. A slipper 21 is carried by the rod 19 and a stay 20 fixed to the rod 19, and a roller 33 is carried by a bracket 42 supported by rods 29 adjustably mounted in brackets 28 on the rods 12. The soundboard, with the iron frame and bridge secured thereto, is supported by a table 34 mounted on wheels 35 which run on rails 36 on a truck 37 running on stationary rails 38, so that the table is free to move in any direction in an horizontal plane. A rail 39, Fig. 3, carried by wooden strips 40 is placed over the wrestpins, and the cutter is lowered by the lever 5 until the slipper 21 rests on the rail. The soundboard is then moved under the cutter, the side of the bridge-piece being kept in contact with the roller 33. The depth to which the bridge is cut is determined by the position of the sleeve 14. An adjustable stop-nut 26 is provided to limit the movement of the sleeve. A hinged prop 41 supports the lever 5 while a soundboard is being placed on the table.