Popular Science Monthly 



735 



An Electric Semaphore Signal for 

 the Automobile 



LIKE an ordinary semaphore, the elec- 

 j trically - lighted automobile signal 

 shown in the illustration drops to a hori- 

 zontal position to indicate the direction 

 the car will take in turning. 

 As the arm drops, it is lighted 

 automatically. 



The entire signal consists 

 of two semaphores attached 

 to the sides of the windshield 

 and operated by means of wires 

 tightly wound around small 

 drums on the dash. 



Small knobs on ,^''' 

 the drums allow /' 

 the driver to / 

 drop either / 

 light at will by / / 

 turning either j^^^, — 

 knob and re- v__^ 

 leasing the 

 wires. Red and 

 green lights are generally 



used for such signals. The arms drop by gravity and ived 

 to their vertical position by turning knobs 



Stock Power Sand Screens for 

 Small Jobs 



EASILY movable from place to place 

 on a contracting job, the power-driven 

 sand and gravel screen shown in the accom- 

 panying illustration is designed for 

 small jobs where the cost of erecting 

 a permanent screen would be pro- 

 hibitive but where the old hand 

 methods would prove too slow and 

 too costly. 



The screen consists of an open 

 cylinder carried on a shaft at its 

 center and supported on a metal 

 framework with small wheels on the 



bottom. The cylinder is made in several 



ring sections over which are bolted semi- 

 circular screens covered with wire netting 

 of close and open weave. 



The sand is fed into one end of the 

 screen by means of a hopper and chute. 

 As the screen revolves, the sand passes 

 through the meshes of the dif- 

 ferent sections, the finest 

 sand dropping through to 

 the ground first and the 

 large stones passing 

 through clear out to the 

 end. The varying 

 grades of sand are sepa- 

 rated on the ground 

 by means of small 

 boards as shown 

 in the picture. 

 Another un- 

 usual feature 

 of the screen 

 shown is a me- 

 chanical screen 

 cleaner work- 

 i ng on the 

 hammer or im- 

 pulse principle. This cleaner consists of 

 an inverted U-shaped frame bolted to the 

 sides of the screen framework over the 

 section having the finest screen. A hori- 

 zontal arm pivoted to one of the vertical 

 arms of the U-frame ter- 

 minates in a small metal 

 roller at its free inner 

 end which contacts by 

 gravity with a narrow 

 steel ring around the 

 screen, imparting ham- 

 mer-like blows to the 

 ring and screen suffi- 

 cient to jar free any 

 particles clogging it. 

 "The use of wire screens 

 instead of perforated metal 

 is a new departure in small 

 capacity screens. It has 

 been found that the rough- 

 ness of the wire netting 

 offers sufficient resistance 

 to the sliding mass to hold 

 it until the part that should 

 sift through has fallen out. 

 thus insuring uniform grad- 

 ing of the material. 



The field of the screen i 

 not limited to sand alone 

 It may be used for coal 

 coal screenings and the like 



HAMMER BLOW OEUVERED BY WEIGHT OF 

 ARM AS IT DROPS FROM RAISED BAfiTS 



The apparatus may be driven 

 from the Hghting current 

 or from a portable engine 



