1. Field Of The Invention
The present invention pertains to a stop action valve mechanism for a musical instrument and particularly for a pipe organ.
2. Description Of The Prior Art And Objectives Of The Invention
Pipe organs for use in churches, cathedrals and other large spacious buildings have been in existence for over five hundred years. Pipe organs use stop actions to control the flow of air to the pipes so that the various ranks of pipes can be played or not played individually or in combination. Conventional wind-chest stop actions employing small pallet valves and springs have been long available and are commonly referred to as "spring chests". Another type of stop action mechanism has long employed a slide or wooden strip and is referred to as a "slider". Due to the complications involved in operating and maintaining the spring chests, these types of stop actions have not been in extensive use in several hundred years. However, the slider types are generally used on "tracker" type organs which are built today. Such organs incorporate wind-chests which utilize a series of air channels, one for each note of the keyboard. On top of the grid formed by the air channels is a flat surface referred to as a "table". Sliders are positioned above the table and thereabove is a toeboard upon which rests the organ pipes. One slider is available for each rank of pipes or voice, which may consists of sixty-one pipes. Each wind-chest may contain one to twenty ranks. There is an aperture in the table, the slider and the toeboard which, when aligned, allows air to enter the pipe for sound production.
In conventional organs making a "voice" or rank of pipes playable from two or more keyboards using a "slider" has been impractical, cumbersome and costly. Two air channels must be placed under each pipe, one for each keyboard and there must be two sliders for each rank of pipes, i.e., one to control the air for each of the air channels. Also, a special toeboard with complex channeling is required along with back pressure valves so that the air cannot bleed from one air channel to the other when a particular note is played. Thus, tracker organs today generally have a complete rank or set of pipes for each individual voice on each keyboard and each keyboard requires its own separate wind-chest to play said voices.
Around the turn of the twentieth century organ builders began using electric actions in various forms to control the air entering the pipes. These actions allowed use of a series of switches whereby a single rank of pipes could easily and inexpensively be placed on all keyboards and at different pitches. Organ builders could then take a small number of pipes and make them playable from different keyboards and provide a pipe organ for smaller churches with the advantages of a much larger instrument, at a fraction of the cost. Such electrical actions, while providing versatility and saving initial expense, had one prominent problem. The electrical actions had to be completely rebuilt every twenty years or so at a substantial cost. Routine maintenance has also been a problem with electric control actions. On the other hand, tracker organs generally never have to be rebuilt with only minor maintenance required to keep them in operation for seventy-five to one hundred years.
Thus, with the disadvantages and problems associated with conventional organ mechanisms known, the present invention was conceived and one of its objectives is to provide an organ stop action valve mechanism which is relatively simple in construction, versatile in use and requires little if any maintenance.
Another objective of the present invention is to provide an organ stop action valve mechanism which is easy to maintain like a tracker organ and which provides the versatility of an electric action type organ, i.e., allows different voices or ranks to be played from more than one keyboard.
It is yet another objective of the present invention to provide an organ stop action valve mechanism which utilizes a small planar valve which is slidably mounted on guide pins which closes an aperture over the air channel and includes a resiliently mounted plunger and pivotable valve control member.
Another objective of the present invention is to provide an organ stop action valve mechanism which allows back air pressure to be applied to nearby closed valves preventing air from entering corresponding air channels when one or more valves are opened during playing.
It is still another objective of the present invention to provide an organ stop action valve control member which is hingedly joined to the wind-chest.
Various other objectives and advantages of the present invention become apparent to those skilled in the art as a more detailed explanation is presented below.