TANGLEY CALLIOPE RESTORATION PROJECT (part 4)
by Dr. Bill Black
MORE EXAMINING OF THE INNER PARTS
Last month we looked at the things we could see from the back on the machine. Now we look at the front. In PHOTO A, the front cover has been removed. This machine has seen a lot of use and the keyboard has some severe wear. As the keys are connected to the pneumatic stack, when the machine is playing from the music roll, the keys are also moving up and down. At some point, the keys were recovered with formica, some of which is falling off. We will examine the repair of the keyboard in a future article.
If we remove the keyboard and its bed and turn it upside down, we can examine the underside. In PHOTO B, note the attachment of a metal arm on the underside of each key. These arms serve as an attachment to the linkage to the pneumatic stack. The portion of the metal arm where it attaches to the key also contacts the push rod for the windchest. When the key is depressed, this rod is pushed down to open a valve in the windchest to allow wind to go to the particular pipe.
In PHOTO C we see the linkage. Rods are attached to the arms from the underside of the key. The other end of these rods are attached to a bank of wooden arms which are mounted with an axle through the centers. The rods from the key arms are attached to one end of the wooden arms. The other ends of the wooden arms are attached to other metal rods which are connected to the stack pneumatics.
PHOTO D shows the linkage close up. This intermediate wooden arm linkage serves two purposes. Note that when the stack pneumatics collapses, the motion is in a upward direction. We need to have the motion of the keys in a downward direction to operate the windchest pushrods. So. this intermediate wooden arm with a axle serves to convert the upward motion of the stack pneumatic to a downward motion on the other end of the wooden arm. This end of the wooden arm is connected to the rod going to the key. This arrangement also allows this linkage to fit around the bottom of the windchest.
PHOTO E shows another view of this linkage. In the lower left portion of the photo, we see a pressure relief valve for the pressure tank. The amount of wind pressure which builds up before the pressure spills off is adjusted by the tension of the spring. This spill valve also has a small arm and latch arrangement of the side of the case so the operator can open this spill valve to remove the wind pressure from the machine. When the operator is not playing the machine for a short period, this valve can be opened to take some of the strain off of the blower which is producing the wind to blow the pipes.
Dr. Bill Black is one of the nation's most knowledgeble Wurlitzer band organ experts. He has made recordings of many band organs and other mechanical music machines which are available for purchase in our CarouselStores.com website.