Patent Publication Number: US-7718876-B1

Title: Angled grain drum shell ply configuration

Description:
BACKGROUND OF THE INVENTION 
     This invention relates generally to improvements in acoustic performance of drums, and more specifically to enhancement of production of deeper sounds or tones or pitches from drum. 
     There is continual need for enhanced performance of drums. Deeper acoustic pitch output from drums is desirable, in this regard. 
     SUMMARY OF THE INVENTION 
     It is a major object of the invention to provide improvements in the construction of drum shells to realize deeper pitch outputs from such drums. Basically the improved shell comprises 
     a) multiple wooden curved plys, 
     b) each ply having grain extending in a characteristic direction, 
     c) the grain direction of at least one ply extending crosswise relation to the grain direction of the next adjacent ply about the shell. 
     As will be seen, the grain direction of the one ply typically extends at an angle +α 1  relative to the drum axis, and the grain direction of said next adjacent ply extends at an angle −α 2  relative to the drum axis. For example the following grain directional angularities are found to produce desired significantly lowered pitches:
 
30°&lt;+α 1 &lt;60°
 
and −30°&lt;−α 2 &lt;−60°
 
     Preferably and for deeper pitch development, the angularities are as follows:
 
+45°≅α 1  
 
−45°≅−α 1  
 
     A further object of the invention is to provide said one ply as defining a cut extending at an angle +β 1  relative to the drum axis, and the adjacent ply defines a cut extending at an angle −β 2  relative to the drum axis, these cuts extending between upper and lower edges of the plys. Typically, α 1 =β 1  and −α 2 =−β 2  whereby grain directional continuity is maintained at opposite sides of the cuts, and between upper and lower edges of the plies. 
     A yet further object is to provide cuts through the multiple plys, the cuts substantially angularly equally spaced about an axis defined by the shell. 
     These and other objects and advantages of the invention, as well as the details of an illustrative embodiment, will be more fully understood from the following specification and drawings, in which: 
    
    
     
       DRAWING DESCRIPTION 
         FIG. 1  is a vertical section taken through a drum assembly;  FIG. 1   a  shows a modification; 
         FIG. 2  is a fragmentary horizontal section taken on lines  2 - 2  of  FIG. 1  through multiple plys or laminations; 
         FIG. 3  is a fragmentary side view taken in elevation on lines  3 - 3  of  FIG. 2 ; 
         FIG. 4  is a perspective view of multiple plys or laminations for use in a drum, and broken away to show grain angularities of radially successive plys; and 
         FIG. 5  is an enlarged fragmentary view showing bonding of successive plys. 
     
    
    
     DETAILED DESCRIPTION 
     In  FIGS. 1 and 2 , a drum  10  has a metal shell  11  with a first wall section  12  consisting of wood, a second wall section  13  and a third wall section  14 . The section  12  is preferably located between sections  13  and  14 , so that drumheads  15  and  16  may stretch over annular beveled metallic edges  17  and  18  that do not “weather” or otherwise change with atmospheric or other conditions. Sections  13  and  14  may have interfit with section  12 , as for example at end locations  12   a  and  12   b . Also sections  13  and  14  may preferably and alternatively comprise axial extensions of section  12 , so that only one section  12  made of wood is provided. See  FIG. 1   a  showing wooden lamination end taper at  17   a    
     Sections  12 ,  13  and  14  then each typically consist of radially overlapping wooden laminations, and section  12  and laminations  12   c  may extend to opposite end locations  17  and  18 . The grain in radially successive laminations extends at alternate angles +α 1 , −α 2 , +α 1 , −α 2 , etc as later defined, for audio output tone control. 
     In the drum example shown, means is also provided for retaining the drumheads on the drum, including flanges at axial ends of the drum, retainers on one of the sections, and adjustable tensioning means interconnecting the flange means and retainer means. In the example, flange structure  20  is provided in association with metal section  13  of the shell, and flange structure  21  in association with metal section  14  of the shell. Retainer elements  23  are spaced about and adjacent the outer surface  24  of wooden section  12 , mid-way between metal sections  13  and  14 , and the elements  23  may have circular cross sections and consist of brass. See U.S. Pat. No. 6,525,250 incorporated herein by reference. The elements  23  carry tubular holders  25  projecting vertically and parallel to the drum axis, but in axially opposite directions. Tightening adjustment fasteners  26  project radially through the shell section  12  to affix the elements  23  to the outer surface of the section  12 . 
     The upper flange structure  20  has an upwardly extending annular rim portion  32  extending above the level of drumhead  15 , a medial annular flange portion  33  extending radially outwardly below the level of  32 , for transmitting head tightening loading, and a lower annular portion  34  extending downwardly from the outer extent of  33 . A tightening adjustment fastener or tensioner rod  36  extends downwardly through  33 , and its lower end has external threads  37  that interfit rotatably internal threads in upper holder  25 . Note fastener head  36   a  bearing on the upper surface of  33 . The lower surface of  33  exerts downward loading onto a retention ring  38  to which drumhead  15  is suitably attached, for tightening (or loosening) same, by drawing the head over  17 . 
     Likewise, lower flange structure  21  has a downwardly extending annular rim or flange portion  43  extending below the level of drumhead  16 , a medial annular portion  44  extending radially outwardly above the level of  42  for transmitting head tightening loading, and an upper annular portion  44  extending upwardly from outer extent of  43 . A tightening adjusting fastener or tensioner rod  46  extends upwardly through  42 , and has external threads  47  that interfit rotatably the internal threads in lower holder  25 . Note fastener head  46   a  bearing on the lower surface of  42 . The upper surface of  43  exerts upward loading onto lower retention ring  48  to which drumhead  16  is suitably attached for tightening (or loosening) same, i.e. over bevel  18 . Accordingly, the drumheads are individually adjustable. 
       FIG. 4  shows a shell or shell section  100  having multiple wooden curved plies or laminations  100   a ,  100   b ,  100   c  and  100   d , in radial overlapping succession. Successive plies are typically bonded together as by adhesive shown at  101  in  FIG. 5 , under radial pressure exerted as shown by arrows  102  and  103 . The plies may consist of oak, ash, or other suitable wood. Each ply is typically between ⅛ and ⅜ inches in thickness. 
     Each ply has grain extending in a characteristic direction, the grain of at least one ply extending crosswise relative to the grain direction of the next adjacent ply. See grain  100   aa ,  100   bb ,  100   cc , and  100   dd , directed as shown. Grain  100   aa  extends crosswise relative to grain  100   bb , and  100   bb  is crosswise relative to  100   cc , etc. The crosswise angularities are indicated at +α i  and −α 2  in radial succession. 
     Typically the following angularities are provided for successive and alternate laminations
 
30°&lt;α 1 &lt;60°
 
−30°&lt;−α 2 &lt;−60°
 
and preferably
 
+α 1 ≅45°
 
−α 2 ≅−45°
 
and where more than two laminations are provided:
 
first lamination: α 1 ≅45°
 
second lamination: −α 2 ≅−45°
 
third lamination: α 1 ≅45°
 
fourth lamination: −α 2 ≅−45°
 
etc.
 
Preferably, each shell has between 2 and 8 laminations.
 
     A second feature of the invention consists in that one ply defines a cut extending at an angle +β 1  relative to the drum axis, and the adjacent ply defines a cut extending at an angle −β 1  relative to the drum axis, said cuts extending between upper and lower edges of the plys. See for example cuts  70  and  71  in  FIG. 3 . Note that grain direction continuity is maintained; at or between opposite sides of the cuts. See for example in  FIG. 3  direction of grains  100   aa  at the lower side of the cut  70  and the same direction of grain  100   aa  at the upper side of cut  70 . The cut extends at angle +β 1  in ply  100   a , at −β 1  in ply  100   b , at angle +β 1  in ply  100   c , −β 1  in ply  100   d , etc. 
     The invention has been found or discovered to provide desirably and significantly enhanced and deeper sonority of drum audio output.