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1948-49 Theatre Catalog, 7th Edition, Page 407 (394)

1948-49 Theatre Catalog, 7th Edition
1948-49 Theatre Catalog
1948-49 Theatre Catalog, 7th Edition, Page 407
Page 407

1948-49 Theatre Catalog, 7th Edition, Page 407

FIG. Z-Right-hand side of lamp showing carbon feeding and burner mechanisms.

from the arc according to condenserfocusing requirement.

The rear dowser is pivoted below and to the left of the optical center, hence it swings upward and to the left of the condenser when it is open and is completely out of the path of the arc tail flames (Fig. 2).

Condenser-Lens Holder

A totally new and highly efficient method of lens mounting is accomplished by providing the condensermount casting with several narrow machined prongs into which the rear lens fits. Contact with the rear lens is only at these points. Accurate spacing of the condensers is had by a spun sheet-metal separator ring having several thin sheetsteel radial webs that contact the curved surface of the rear and front lenses. Hence variation in the thickness of the edges of the lenses will cause no change

in the correct spacing of their facing curved surfaces. Both lenses with their separator are retained in the main holder casting by a threaded ring at the front of the holder, which likewise is provided with prongs to hold the lenses and spacer assembly in place and in alignment. Thus means are provided to use the full aperture of both condensing lenses (Fig. 4).

Lamphouse Side Doors

The right side of the lamphouse door has two arc-viewing ports, the front one for direct viewing of the arc and the rear one, which is provided with a lighter colored glass, may be used to View the operation of the burner mechanism and to determine carbon length, and so on. The glasses are held in their frames by springs and hence are easily replaceable. An arc-image projector is also built onto the outside of the right side

FIG. 3-Lamp from front and right-hand side.

door. It includes a ground-glass screen upon which is projected an image of the burning arc. This screen is recessed into the door and the image is visible to the projectionist from the rear as well as the front of the lamphouse. The angle of the screen may be altered to a vertical plane, notwithstanding the angle at which the projector and lamphouse may be inclined.

The left side of the lamphouse door is provided with only one viewing port having a dark glass for viewing the are when it is lighted.


The arc-burner mechanism, including the carbon-feeding mechanism, blower unit, and motor, are built as a complete unit and held in position inside of the lamphouse by only one screw at the rear and a threaded stud at the front end. It is completely removable with a minimum of effort (Fig. 6).

The carbon-feed mechanism (Fig. 7) attaches to the burner-base casting at the rear end. The feed-mechanism main frame also provides the mounting for the blower unit and feed motor. As before stated, a positive supply oftair is directed into the lamphouse via the channeled burner base which is utilized as an air duct and air distributor.

To provide a wide latitude of carbonfeed speeds for each carbon, infinitely variable hardened and ground overriding clutches are provided. This arrangement allows the use of a constant-speed motor, hence the motor operates at its maximum torque at all times and eliminates the need of a controlling rheostat in the motor circuit. Likewise this method of drive results in a constant rotating speed (18 revolutions per minute) of the positive carbon, regardless of the rate of feed thereof.

The lineal feed of the positive carbon is variable between 0 and 35 inches per hour and the feed of the negative may be varied from 0 to 8 inches per hour which amply takes care of the consumption rate of all currently available highintensity projection arc carbons.

The burner accommodates a 22-inchlong positive carbon without resetting, and 4% inches of the 9-inch negative can be fed at one setting, this is more than suificient to last through the burning of an entire length of positive carbon.

Handles for the manual control of the carbons or adjustment of the arc extend outward from' the right side of the carbon-feed mechanism and are convenicntly located.

The burner as a complete unit may be raised, lowered, and moved laterally within the lamphouse to place the positive carbon crater in the optical axis to the projector.

The positive carbon is fed forward and rotated by a carriage which travels on two ground steel tubes. The right side of the tube is slotted to permit engagement 0f the carriage follow-pin tooth into the acmeethreaded feed screw which rotates within the tube.

Convenient means have been provided to disengage manually the positive carriage follow pin from the longitudinal feed screw to allow rapid hand movement of the carriage in either direction

1948-49 Theatre Catalog, 7th Edition, Page 407