Document o9BXNpVeV3prJdgqexd0zeLyX

MACHINE TOOLS TABLE 24-1 DIMENSIONS FOR BAND TYPE GUARDS FOR ABRASIVE DISKS guard is to retain the pieces of the disk or wheel if it should be broken in operation Safety guards (protection hoods) should be constructed so that In changing wheels there is no need for removing the peripheral member which Is connected to the machine Guards on machines used for dry grinding should have provisions for connecting to an exhaust system Table 24-H gives the material specifications for safety guards Safety guard is a general term and in cludes all of the following specific types Band type guard Cast guard Drawn steel guard Fabricated guard Revolving cup type guard A band type safety guard is designed es pecially for an abrasive disk where grinding is done only on the exposed side of the disk and where its diameter remains constant The band type guard differs from other safety guards in that it consists only of a properly supported peripheral member or band This band is continuous and com pletely surrounds the disk, and though Its diameter is only sbghtly larger than the disk diameter, it need not be as heavy as other types of guards tliBt are used on abra sive wheels A band type guard should be made of wrought iron or steel plate or other mate rial of equal or greater strength It should be continuous and should conform as closely as practicable to the periphery of the disk The ends should be riveted, bolted, or weld ed together so as to leave the inside of the band free from projections The inside diameter of the band should be not more than 1 in larger than the outside diameter of the disk The band should be wide enough and kept in position so that at no tune will the disk protrude beyond the edge of the band farther than maximum exposure (G) indi- 24-22