Document K10KOwjMpv9mJN9rxpY1kLJ0

Hoisting Apparatus and Conveyors radius to deliver packages onto the lower floor without impact or damage Some gravity-chute conveyors are built m the form of a spiral around a vertical pipe with a slope at the outer edge between 18 and 30 degrees In removing packages from the delivery end of spiral chutes, workmen ffequendy in jure their hands, which become caught by descending packages or are mashed against others on the delivery table Where the chute is enclosed, a warning sign should be placed over the delivers' end A simple me chanical or electrical device that will give warning when a package is about to be de livered from the chute is advisable, especially where the packages cannot be plainly seen in descent Spiral chutes present a senous fire hazard because they form flues from lower floors to upper floors through which fire will spread quickly Two methods of eliminating this hazard are m general use one is to enclose the chute in a tower made of fire-resistant maicnal, such as steel, concrete, or masonry, the other is to provide automatic fire doors (draft checks) where the chute passes through floors The enclosed tower has doors at each charging station and a door at the delivery end The charging station doors should be kept closed, except when charging is being done The door at the delivery end should close automatically m case of fire Shutoff doors (draft checks) are of two kinds--the vertical sliding and the shutter tvpe Both types should have fusible links so that they will close automatically in case of fire Where an open chute is used, a guardrail and toeboard should be provided at each floor The charging stations should be guarded either by a movable railing or by a hinged door or gate Roller or wheel conveyors Gravity roller or wheel conveyors are similar to chute con veyors, except that the angle of slope is much less (2 to 4 per cent) The conveyors, there fore, can be used to convey packages for con siderable distances on one floor If the rollers or wheels are placed radially instead of paral lel, the course of travel can be changed from a straight line to a curve The principal hazards m the use of roller conveyors are that material may run off the edge of the rollway and fall to the floor, and that loads may run away A guard railing often is provided on each side of the roller conveyorway, to guide the material and pre vent it from running off Such guardrails are especially advisable at comers and turns and on elevated conveyors under which men must work or pass Where heavy loads are conveyed, retarders, brakes, or similar means should be provided to prevent the loads from running away, or a power conveyor on which speed can be con trolled should be substituted A vertically swinging hinged section of a roller or wheel conveyor should be hinged to that end of a stationary section of the conveyor from which the material is flowing to help block the oncoming material The open end of the conveyor line should have a stop that automatically projects above the level of the rollers or wheels when the hinged section is opened and automatically retracts when the hinged section is closed Where a horizontally swinging hinged sec tion occurs in a conveyor, the open ends of stationary sections (the two ends adjacent to the hinged section) should be equipped with retractible stops to prevent loads from drop ping off the conveyor when the hinged sec tion is open Live roll conveyors A live roll (or roller) conveyor consists of a senes of rolls over which objects are moved by power applied to all or some of the rolls through belts or chains Where installed at floor level or used in working areas, live roll conveyors should be designed to eliminate hazards from pinch points and moving parts, unless other provi sions are made to prevent personnel from coming in contact with or crossing the con veyor Vertical conveyors Vertical conveyors handle packages or other objects in a vertical or substantially vertical direction The Conveyor Code designates three types Vertical reciprocating conveyor a power- or gravity-actuated unit that receives 576