Abstract:
A drum lug assembly, comprising, in combination first and second lugs attachable to the outer side of the drum shell, the lugs interconnected and defining aligned bores, and a receiver for a tensioning rod floatably coupling to at least one of the lugs.

Description:
BACKGROUND OF THE INVENTION 
   This invention relates generally to the construction of drums, and more particularly to self-adjustable tensioning of drum heads to drum shells. 
   Drum heads are typically held onto opposite ends of drum shells by tensioning means at the outer sides of the shells. Such tensioning means typically include tensioning rods threadably connected to drum lugs. Those connections are fixed, and do not allow relative angular position adjustment as between rods and lugs. This can introduce problems, such as differential tensioning due to rod binding, as respects the multiple independently adjustable rods spaced about the drum shell, which can in turn cause undesirable differential tightening of the drum heads. This has been a problem in the past. 
   SUMMARY OF THE INVENTION 
   It is a major object of this invention to provide a simple and highly effective solution to the above problem. Basically, the invention is embodied in an assembly that comprises, at each rod location: 
   a) first and second lugs attachable to the outer side of the drum shell, 
   b) said lugs having interfit and defining aligned bores, and 
   c) a receiver for a tensioning rod floatably coupling to at least one of the lugs. 
   One or two receivers may be provided, for a tensioning rod or rods floatably coupling to at least one of the lugs, on either one side or both. 
   As will be seen, the receiver typically has a bore thread for coupling to the tensioning rod; and the rod is thread connected to said receiver bore thread, and extends in said aligned bores for limited sideward deflection in at least one of said aligned bores. This enables self adjustment of the rod relative to the lug or lugs as during rod tightening, this being is particularly effective in the case of rod mis-alignment with the lug bore. 
   Another object is to provide the receiver with a coupling flange, for floating coupling to one of the lugs, and a stem protruding relative to the flange, with clearance between the stem and one of the aligned bores, allowing limited lateral deflection therein, for self adjustment. 
   Yet another object includes provision of a non-metallic seat in the assembly to cushion flange endwise movement. 
   A further object includes provision of at least one of the lugs to have external oval configuration and defines a long oval axis generally parallel to said bores. Both lugs may have such configuration, to be fastened to the outer side of the shell. An elastomeric gasket or gaskets may provide cushioning between the lugs and shell, allowing further lug self adjustment during use. Dual lugs for dual retainers are also provided. 
   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 section taken through lug apparatus; 
       FIGS. 2 and 3  show lug positioning on a drum shell; 
       FIG. 4  is a schematic view in perspective of lugs on a shell; 
       FIG. 5  is a section showing a prior art shell and drum heads; 
       FIG. 6  is a section like  FIG. 1 , but showing a modification; and 
       FIG. 7  is a view like  FIG. 2 , but showing  FIG. 6  type modified lug attachments to a drum shell. 
   

   DETAILED DESCRIPTION 
   Referring first to the preferred embodiment shown in  FIG. 1 , the drum shell  10  supports first and second lugs attached to the outer side  10   a  of the shell. One of such lugs is indicated at  11 , and the other at  12 . Threaded fasteners  13  and  14  are shown connecting the lugs to the shell outer side  10   a , as via openings  15  and  16  in the shell and in lug  11 , and as via openings  17  and  18  in the shell in lug  12 . Washers are provided at  19  and  20 , and at  21  and  22 . 
   The lugs have interfit as at bore  23  in lug  11  receiving projection or stem  24  of lug  12 . The lugs also have axially aligned bores, as at elongated bore  26  in lug  12 , and stepped bores  27  and  28  in lug  11 , there being a bore shoulder provided at  29 , between  27  and  28 . 
   A tubular receiver  30  is received in bores  27  and  28 , and has a flange  31  engagable against shoulder  29 . That receiver has a threaded bore  35  for threaded reception of an adjustable tensioning end  33 , serving to tension a drum head schematically shown at  34 . Multiple such rods are spaced about the shell, for individual rotary adjustments to precisely tune the drum head, whereby the rods may resultantly extend in slightly out of parallel relation. Such out of parallel relation is accommodated in simple effective manner by the present invention. 
   To this end, the receiver  30 , connected to the tension rod, is floatably connected to the upper lug  11 , to allow the tensioned rod and receiver  30  to angularly deflect sidewardly to become slightly mis-aligned with bores  26 - 28 , in response to differential tightening of the multiple tensioner rods referred to, without causing interruption of tightening of the tension rod as could result from seizing or binding of the threaded connection between the rod and the receiver if no such lateral deflection were enabled. In this regard, axial loading is transmitted between flange  31  and shoulder  29 . A non-metallic seating washer  36  is provided between the bottom surface  31   a  of flange  31  and the top  12   a  of lug  12 , with clearance therebetween at  37 , to allow angular mis-alignment of the washer and flange, relative to the axis of bore  27 . 
   It will be understood that at least one of the lugs, and preferably both of them, may have external oval or rounded configuration, as seen at  11   d  and  12   d  in  FIG. 3 , defining an oval axis  50 , or axes extending in the direction  40  parallel to the bores  26 - 28 . This contributes to the interfit functioning of the lugs, as referred to. Also elastomeric gasket or gaskets  42  and  43  are positioned between the lug surfaces  11   c  and  12   c  and the curved outer surface  10   c  of the shell, whereby the metallic lugs and shell are insulated against audible sound transmission therebetween. Also, the lugs may slightly deflect relative to the shell, in response to tension rod differential tightening, as referred to, contributing to non-binding of the rods as they are tightened, in the manner referred to. 
     FIGS. 2-4  show like pairs of lugs  11  and  12  extending in endwise opposite directions for adjustably tensioning rods extending to drum heads at opposite ends of the shell. 
   In  FIGS. 6 and 7 , elements the same as in  FIGS. 2-4  are given the same identifying numerals. In  FIGS. 6 and 7  the two lugs are identified as  11  and  11   a , since the lower lug  11   a  is like lug  11 , but endwise reversed. The lugs may have oval or rounded external configurations. Likewise, first and second receivers  30  and  30   a  are provided, and which are alike, but relatively endwise reversed. Upper and lower tensioning rods are indicated at  33  and  33   a . Receiver  30  is floatably coupled to upper lug  11 , and receiver  30   a  is floatably coupled to lower lug  11   a . Rods  33  and  33   a  extend toward opposite ends of the drum shell to adjustably tension drum heads at those ends. 
   Also provided is a tubular connector component  75  having opposite ends  75   a  and  75   b  connected to the lugs, as at  76  and  76   a , to extend between and in alignment with the receivers  30  and  30   a . Component  75  acts as a spacer to position the lugs in endwise spaced relation, and distributing endwise force in balanced relation and as between the fasteners which connect the lugs to the drum shell. Each lug has spaced and stepped shoulders, as at  77  and  78  engagable with shoulders on the component and on the receiver, to transmit such axial loading, in balanced relation as between the lugs, but allowing for floating deflection. 
   In addition, plastic compressive seating cushions or inserts  79  and  80  are located between the ends of the receivers, and of the component  75 , to allow each receiver to angularly deflect sidewardly to limited extent, as provided by the clearance between the receiver shaft and the lug bore, as previously discussed. Dual independent deflection of the receivers allows for maximum sideward self-adjustability during endwise adjustment of the rods  33  and  33   a , preventing binding. The configuration of  FIGS. 6 and 7  is preferred. 
     FIG. 5  shows a prior art rod  81  and  82  configuration at the side of a drum shell.