Transparent Mystery Clock, gilt base
2019 Inventory Description: Etalage Reclame Corp. Transparent Mystery Clock.Gilt metal base, brown power cord. Clear glass face with tan and blue numbers and gilt hands.
Boettcher Deed Inventory: One etalage crystal and gilt metal electric mantle clock, 7 1/4" dial, modern design.
The next two description blocks describe the clock mechanics and patent, from http://www.roger-russell.com/etalage/etalage.htm
This clock is similar to the Prins patent number 2,248,195. It was applied for on April 30, 1937 and issued on July 8, 1941. It was reissued May 1, 1945. Application for reissue was June 14, 1944 serial number 540,233. The patent describes a clock with two transparent rotating discs, one for the minute hand, and one for the hour hand. The geared perimeters are driven at different speeds from different gears in a gear train driven by a motor. The two discs are enclosed by front and back transparent discs. The clock differs from the patent in that the hour and minute discs are of equal diameter.
In the clocks pictured at the left, there are four glass discs. The front one has beveled edges and has the numbers painted on the back of the glass. The second disc has the minute hand glued to it. The minute hand is solid metal 3" long and 3/32" square. The Third disc has the hour hand glued to it. The hour hand is solid metal 2-1/8" long and 3/32" square. The rear disc is clear and has a beveled edge. It's there for protection. Three clamps hold the front and back discs in place. They are located at 12, 4 and 8 o'clock and each is attached to a cast metal outer ring with two screws. The numbers 10, 11 and 12 on the front glass are styled with the 1 being shorter. The clocks were sold with either a chrome or gold finish. The numerals are the same color in both clocks. They are yellow with a dark blue outline.
The steel base plate is force fitted into place inside the base. It has a green felt pad in each corner that is 3/4" in diameter. The plate is stamped with Etalage Reclame Corp., New York. AM patents 2,248,195, 2,201,376 and 1,855,648. There is no model name or number.
The clock is 9-5/8" high. The dial is 7-3/8" in diameter and 1-3/16" thick. The base at the bottom is 5-5/8" wide and 2-3/4" deep. It weighs 1750 grams or about 3.8 lbs. It comes with a 5-foot 5-inch brown line cord that has a small molded white plug on the end.
The outer ring contains all four pieces of glass. Here's a picture of the bottom portion of the ring. The time set knob is at the rear of the clock and can be seen at the bottom left side of the picture. The two inner discs are 6-7/6" in diameter and are each glued to an outer gear ring that has 360 teeth. The teeth of the outer ring are triangular much like a saw blade. The rings are made of steel. Each disc and ring weighs 163 grams or about 5.8 ounces. The outer beveled pieces of glass are 7-5/32" in diameter.
Much of the weight rests on two free turning brass wheels shown at the right of the gears. Each ring is shaped so that the teeth engage the brass drive gears that each have 36 teeth. This makes a gear reduction of 10 to 1. The front gear (at the top of the picture) turns the minute hand disc at one revolution per hour. The rear gear turns the hour hand.
A Synchron motor is located in the base and is made by the Hansen Mfg. Co., Inc, Princeton, Indiana. It is model 600, 4 rpm, 110V, 60C. The gears in the picture are located in the neck of the clock. The view is from the bottom with the motor removed. These gears reduce the rotation of the motor shaft from 4 rpm down to 1/6 rpm for the minute hand gear. They further reduce the rotation for the hour hand gear to 1/72 rpm. Combined with the 10 to 1 reductions to the minute and hour discs, this provides the required 1/60 rpm for minutes and 1/720 rpm for the hours.
A worm gear on the shaft of the motor drives the upper left gear in the picture. A spring can be seen just below this gear. A smaller shaft for the time set knob goes through the spring to the 2-piece gear at the bottom left. The spring provides a friction clutch coupling from the motor to the 2-piece gear at the bottom left. The larger portion drives the minute hand disc. The smaller portion drives reduction gears to the hour hand.
The hour drive gear is the large gear at the top of the picture. At the right of the picture are the two free turning brass wheels.
The set time knob can be turned in either direction. This will advance the minutes forward or backward. There is no separate advance for the hours and many turns may be needed to set the correct time.
Donated as part of the original Boettcher collection donated by Edna Boettcher in 1960. On exhibit/in use at Governor's residence since 1960.