OP-755 Part 2 Pages 197-401 - Personal Page of GENE SLOVER

262
Powder Car
17. The powder car is an assembly of a large box-shaped
aluminum casting Yfith two til table trays, four guide-wheels,
a safety brake mechanism, * a cam bracket, safety latch stops,
a switch operating bar, anupper door interlock trip and other
attached devices. The car is closed at top, bottom, rear and
sides. In the open front the two powder bag trays are horizontally
pivoted with axes spaced 22.5 inches. Both trays
have limited tilt against rubber pad stops; each is separately
opera ted to tilt from normal position by a hand lever on one
side which has detent arrangement to latch in normalor~oisting
position. Completely assembled and installed in the hoist
the unit weighs 1715 pounds (without service load). The design
arrangements.are shown on drawing number 216452.
18. The guide wheels are bracket mounted at the four
rear corners of the car. The two upper and the rear lower
brackets are fixed;. the forward lower is pivoted and spring
loaded to compress its wheel against the guide rail, its movement
however is limited to approximately one-half inch.
19. The safety brake mechanism* comprises two pair of
serra ted arc shaped rail grabs pivoted in brackets which are
located on each side at the top of the car. These grabs straddle
the respective rails and are held clear as long as the car
hoisting rope tension is maintained under load equivalent to
approximately one-half of the weight of the car. The arrangement
that accomplishes this function is a spring loaded toggle
~ linkage, operating levers, operating bars and a rope guide
t block assembled at the top of the car with springs and other
elements. The guide block at the center is interposed between
two of the operating levers in such manner that when the rope
fails the block will free the levers. The latter under spring
load will than move together and will I
pair of rail grabs. The arrangements
simultaneously free both
of this car subassembly
are shown on drawings number 216452, 216472 and 216475.
20. The safety latch stops are steel blocks bolted to
the sides of the car at the front and arranged in pairs, two
at the bottom and two 22.5 inches above. They are positioned
for emergency support of the car at upper and lower unloading
positions respectively when the safety latches move beneath
them as the car approaches those stations.
21. The two vertical front edges of the car are cam surfaces**
which function to displace the two safety latches as
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* Safety brakes have been removed.
** These cam surfaces have been extended upward by two.we1dments which are
attached to the top of the car (Orda1t 1099).