GB803744A - Improvements relating to guard arrangements for circular saws and like rotary tools - Google Patents

Abstract

803,744. Machinery guards. BRITISH THOMSON-HOUSTON CO., Ltd. April 10, 1957 [April 24, 1956], No. 12526/56. Addition to 790,233. Class 80 (4). A displaceable guard for a rotating tool such as a circular saw 2 projecting through a table 3 comprises for each side of the saw two rotatable discs 19, 20 carried on pivoted arms 15, 17 and an intermediate plate 6 overlapping the discs and carried on parallel links 7, 8. The arms and links are pivoted on a rib 4 of a fixed shield 1. The arm 17 is preferably bifurcated at its pivot end and formed with a quadrant 171 guarding the space between the two coaxial discs 20. An extension 24 on the arm 17 co-operates with a stop 22 on an extension 5 of the rib 4. The arm 15 comprises a pair of members lying on opposite sides of the extension 5 and connected by a bridge 23 co-operating with a fixed stop 21. Each of the two plates 6 is carried by a link 7 and a link 8, the two links 8 being connected by a bolt and spacer 12 passing through an aperture 13 in the extension 5. A stop 14 co-operates with one or each of the links 8. The stops 14, 21, 22 determine the height of the plates and discs above the table and may be provided with rubber pads. The stops 21, 22 may, however, be omitted so that the discs rest on the table 3. When material of thickness less than the spacing h between the plates 6 and table 3 is fed to the saw it engages and lifts the discs 20, passes beneath the plates 6 and then engages and lifts the discs 19. If, however, the thickness is greater than the spacing h, the material lifts the discs 20 sufficiently for rollers 28 on the disc spindle to come into engagement with nose portions 29 of the plates 6 to raise the plates, and in turn tail portions 30 of the plates engage rollers 31 on the spindle of discs 19 and start to raise the discs 19. It is stated that for each side of the saw a further disc or discs may be provided.