TANGLEY CALLIOPE RESTORATION PROJECT (part 19)
by Dr. Bill Black
THE REWIND / PLAY SHIFTER
This pneumatic mechanism serves to control the operating mode of the roll frame. In the one position, the roll frame is in the mode which will play the music roll and the other mode serves to rewind the music roll and return the frame again to the play mode after the rewind phase. PHOTO A shows the unrestored shifter.
The shifter is composed of three parts, the large pneumatic to move the mechanical linkage of the roll frame, the middle portion which houses a primary and secondary valve, vacuum inlet nipple and the end which has a valve pneumatic assembly to release the large pneumatic from the rewind position.
In PHOTO B we are looking at the back of the large pneumatic. In the photo we can see a spring loaded valve and a small nipple. PHOTO C shows the removed valve. The stem on which the valve facing is mounted extends thru a hole in the pneumatic. When the valve is held in the closed position by the spring, a portion of the stem extends into the pneumatic (PHOTO D). When the large pneumatic closes, the inside of the front of the pneumatic contacts this stem and forces the valve open. Under the valve facing is a hole which is connected to the small nipple. So, when the facing is forced up, atmospheric pressure is allowed to flow thru the nipple. This serves to trigger the stack cutout to operate. (More on this mechanism when we work on that).
PHOTO E shows the center portion of the shifter. The large pneumatic requires more vacuum to operate quickly than a single valve can supply. A secondary valve is triggered by the primary and provides a greater flow of vacuum. Also in PHOTO E you can see the block mounted on the end which will provide a mounting block for the valve pneumatic and an internal vacuum channel for this valve. Access to the bleed cups for these valves are provided by small wooden covers screwed on the side of the blocks.
PHOTO F shows the finished shifter. Restoring the unit consisted of cleaning it up, recovering the pneumatics, new pouches, new valve facings and making a new mounting block. I notice that on some of the wood parts of the calliope, Tangley stained some of the wood to make it look like a sort of mahogany color. So, I used Minwax stain to also create this effect.
The sequence of operation is as follows.
- The large pneumatic is open (no vacuum applied) and the roll frame is in the play mode.
- At the end of the music roll, the rewind perforation goes over the rewind hole in the trackerbar.
- Atmospheric pressure arrives at the primary valve in the shifter and the primary valve triggers the secondary valve and supplies vacuum to the large pneumatic causing it to collapse.
- When the pneumatic is collapsed, the latch on top the pneumatic is engaged and the pneumatic is held in the closed position.
- The collapsed pneumatic pulls on the linkage to the roll frame and shifts it into rewind.
- The rewind hole in the tracker bar is again covered as the roll rewinds. Vacuum to the pneumatic is released.
- When the pneumatic is held in the closed position by the latch, the stem described above forces the valve open on the back of the pneumatic open. Atmospheric pressure flows thru the small nipple and triggers the stack cutout to block the vacuum supply to the main stack preventing the music roll from playing during rewind.
- The music roll continues to rewind until the play hole in the roll crosses over the play hole in the trackerbar. Atmospheric pressure flows to the valve pneumatic on the top of the unit.
- The pneumatic on the valve pneumatic unit collapses and the small finger on the pneumatic forces the latch holding the large pneumatic in the closed position to be released.
- The spring mounted between large pneumatic and the roll frame pulls the large pneumatic open moving the roll frame into the play mode.
- When the play hole in the tracker bar is no longer exposed as the music roll moves forward, the valve pneumatic is released.
- 1When the large pneumatic opens the valve on the back closes again, operates the stack cutout and vacuum is again restored to the stack.
- The cycle is complete and the music roll plays once more.
The rewind shifter always has a constant vacuum supply regardless of the mode the roll frame is in. So, the play or rewind function is always available to operate. The calliope has a remote play or rewind valve unit which is accessed from the top of the machine. This allows the operator to shift the roll frame to the play or rewind mode at will.
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.