Patent Publication Number: US-11024268-B1

Title: Pipe organ tremulant

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Not Applicable. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable. 
     REFERENCE TO A “SEQUENCE LISTING” 
     Not Applicable. 
     BACKGROUND OF THE INVENTION 
     Pipe organs have been provided with tremulants of various means to induce pitch variations in pipe organ pipes and have satisfied the need for such devices to a limited extent. 
     Valve means have been used in a pipe organ air supply to release rhythmic pulses of air to induce pitch variations in pipe organ pipes. These devices are complicated, unreliable and expensive to adjust and maintain for consistent performance. Such devices are well known in the prior art, and are illustrated in patents such as U.S. Pat. No. 478,552 to Basset, U.S. Pat. No. 797,719 to Challinor, U.S. Pat. No. 1,243,644 to Van Valkenburg. U.S. Pat. No. 1,262,640 to Cloetens, and U.S. Pat. No. 2,633,047 to Glatter-Gotz. Fan means have been used to disrupt the air flow either of a pipe organ air supply or the ambient air above pipe organ pipes to induce pitch variations in pipe organ pipes. Maintenance access for both is difficult and expensive, requiring considerable relocation of the pipe organ pipes and disassembly of the pipe organ air supply to access the fan. Further, the quality of the tremolo effect varies based on the distance from the pipe organ pipes to the location of the fan. Such devices exist in the prior art, and are illustrated in patents such as U.S. Pat. No. 203,932 to Potter and unpatented devices manufactured by G. W. Ingalls and Co. of Worcester Mass. 
     Eccentric weight means have been used to provide rhythmic increases in the pressure of a pipe organ air supply to induce pitch variations in pipe organ pipes. An eccentric weight is attached to the shaft of an electric motor that is mounted upon an air reservoir bellows. Activating the electric motor causes the air reservoir bellows to rise and fall and provide rhythmic increases in the pressure of the pipe organ air supply. The eccentric weight induces bearing damage to the electric motor. The eccentric weight means is unsatisfactorily noisy. The eccentric weight induces vibration and failure of the air reservoir bellows requiring frequent and expensive replacement of the air reservoir bellows. Movement of the electric motor feeder wires results in work hardening and embrittlement of the feeder wires requiring frequent replacement of broken wires. Such devices exist in the prior art, and are illustrated in patents such as U.S. Pat. No. 1,439,652 to Till, U.S. Pat. No. 2,198,160 to Gollnick, U.S. Pat. No. 3,018,682 to Imhoff and U.S. Pat. No. 4,319,513 to Peterson. 
     Ball means have been used in a pipe organ air supply to release rhythmic pulses of air to induce pitch variations in pipe organ pipes. Prior art ball means have required the continuous manual operation by the organist to provide a tremolo effect or have used a cord to suspend the ball which requires expensive replacement when frayed. Prior art ball means have been unsatisfactorily noisy. Such devices exist in the prior art, and are illustrated in patents such as U.S. Pat. No. 101,742 to Kerigan and U.S. Pat. No. 206,008 to Ewell. 
     Prior art methods for creating a tremolo effect are complicated, unreliable, inconsistent in effect, prone to failure and expensive to maintain. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention overcomes the difficulties of the prior art as outlined above. In accordance with one embodiment, the tremulant comprises a cylinder, a fitting, a bottom stop, vents, a sleeve, a top stop and a plunger. Accordingly several advantages of one or more aspects are as follows: inexpensive materials, ease of construction, simplified maintenance and consistent and reliable operation. 
     Other advantages of one or more aspects will be apparent from a consideration of the drawings and ensuing description. 
     BRIEF DESCRIPTION OF DRAWINGS 
     The single FIGURE shows one embodiment of the tremulant 
     DRAWINGS-REFERENCE NUMERALS 
     
         
           10  90 degree fitting 
           11  bottom stop 
           12  vents 
           13  sleeve 
           14  cylinder 
           15  top stop 
           16  plunger 
       
    
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     One embodiment of the tremulant is illustrated in the drawing. One end of a 90 degree fitting  10  is attached to an air supply of the pipe organ which is not shown. The other end of said 90 degree fitting  10  receives the vertical insertion of the bottom of cylinder  14 . Said cylinder  14  has a bottom stop  11  located above the bottom of said cylinder  14  and below vents  12 . Said bottom stop  11  supports plunger  16  when the tremulant is not in action. Said vents  12  have a total area equal or greater than the area of the cross section of said cylinder  14 . Said cylinder  14  has a sleeve  13  used to adjust the amount of air vented through said vents  12 . Said cylinder  14  has a top stop  15  located above vents  12  that prevents said plunger  16  from escaping said cylinder  14  if said sleeve  13  is blocking said vents  12 . 
     When said air supply of the pipe organ is admitted to said 90 degree fitting  10 , thence to said cylinder  14 , said plunger  16  is urged off said bottom stop  11 . Said plunger  16  then rises until passing said vents  12 , at which point said air supply of the pipe organ is exhausted to the atmosphere. Said plunger  16 , no longer supported by said air supply of the pipe organ, then descends below said vents  12 . No longer vented to the atmosphere, said air supply of the pipe organ once again urges plunger  16  to rise until passing said vents  12 . Said rising and descending of said plunger  16  continues until said air supply of the pipe organ is no longer admitted to said 90 degree fitting, thence to cylinder  14 . The described movement of plunger  16  causes a rhythmic pulsing of said air supply of the pipe organ inducing a tremolo effect in the sounding of the pipes of a pipe organ. Sleeve  13  provides one means of adjusting the amount of air expelled from the vents  12  and thus the rate of the rhythmic pulsing induced by the movement of said plunger  16 . 
     It is to be understood that the invention is not limited to the particular embodiment herein illustrated and described, as many variations may be made in the parts, their relative size, shape and positions without departing from the spirit of my invention as set forth in the following claims.