AU660535B2 - A drum - Google Patents

Description

660535 1

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

0 0i Name of Applicant: Actual Inventor: Address for Service: DONALD ERIC SLEISHMAN Donald Eric Sleishman SHELSTON WATERS Clarence Street SYDNEY NSW 2000 "A DRUM" Invention Title: Details of Associated Provisional Application No: PL1574 dated 27th March, 1992 The following statement is a full description of this invention, including the best method of performing it known to me:- 2 The present invention relates to drums of the type used by musicians.

Such drums essentially comprise an open ended generally cylindrical shell and a diaphragm or skin stretched over each end of the shell. A relatively rigid rim is usually secured to the peripheral edge of each skin and a clamping ring structure in turn engages each rim to secure the skins in place over the shell. The clamping ring is generally loaded in the axial direction 10 of the shell by means of a plurality of adjustable tensioning screws or "keys" extending between the clamping ring and a corresponding series of anchoring lugs fixed to the outside of the shell.

Typically, the anchoring lugs comprise metal blocks 15 bolted securely to the shell intermediate its ends. In relatively shallow drums such as snare drums, there may be a single row of double-ended anchorage lugs disposed at mid height around the shell, with respective tensioning screws or keys extending in both directions from each lug to the corresponding clamping rings. In deeper drums, it is more common to provide two rows of anchoring lugs, each associated with a respective skin.

This arrangement permits independent adjust.t of the tension in each skin, whereby the drum can be tuned.

It is quite common, therefore, for the tension in the skins to be different from each another and consequentl-, the axial loads in the tensioning screws associated with the respective skins do not generally counterbalance one 3 another. As a result, the unbalanced tensioning forces must be supported by the drum shell and so the anchorage lugs must be securely attached to the shell, even in those instances in which a single row of double-ended lugs is used.

It is also quite common for other external fittings such as stands, cymbal supports, other drum supports, pedals, and the like to be mounted directly to the drum shell by means of similar attachment lugs.

As is well known, the primary source of sound from a drum arises from vibration of the skins, one as a result of being dirertly struck by a drum stick or brush, and the other as a result of sympathetic induced vibration. However, it has now been realised that the shell is also capable of resonant vibration, and indeed can contribute significantly to the tone and volume of the drum if it is free to vibrate. It has also been realised that in typical prior art drums, the vibration co.o•i of the shell is substantially hindered or damped by virtue of the relatively heavy metal anchorage lugs i bolted directly to the shell, and by other fittings such as the tensioning screws which are, in turn, secured to •those lugs. The resultant alteration in resonant .frequency and damping of the vibration of the shell produces a sound which is perceived to be of inferior quality.

It is therefore an object of the present invention to provide a drum which overcomes or at least 4substantially ameliorates this deficiency of the prior art.

Accordingly, the invention consists in a drum comprising: a shell; a pair of skins disposed at opposite ends of said shell; and a substantially free floating tensioning assembly disposed to stretch said skins over the respective ends of said shell, said tensioning assembly comprising a pair of engagement means eac for gripping a periphery of a respective one of said skins, a stabilizing ring disposed in spaced apart relation to said shell intermediate the ends thereof, and a plurality of adjustable spaced apart tensioning elements each connecting a respective one of said engagement means to said stabilizing ring, said 4. stabilizing ring and said tensioning elements being disposed in spaced apart relation to said shell and supported by said engagement means without direct fixture to the shell, such that tension is transferred directly between said skins substantially independently of the .shell, thereby permitting substantially undamped "vibration of the shell.

Preferably, said shell has an external diameter and each said engagement means comprises a loading ring engaging the periphery of a respective one of said skins, each said loading ring having an internal diameter marginally greater than the corresponding external diameter of an adjacent portion of said shell.

In the preferred embodiment, discrete tensioning elements extend from each tensioning ring to the stabilising ring. It should be appreciated, however, that continuous tensioning elements may simply extend directly between the loading rings via the stabilising ring.

Preferably also, said stabilizing ring is generally C-shaped in cross section, having a pair of spaced apart flanges and a circumferential web portion extending intermediate said pair of flanges, each of said flanges extending radially inwardly toward said shell from said circumferential web portion. The stabilizing ring further comprises a series of threaded fittings spaced around each of said flanges, each of said threaded fittings engaging a respective one of any one said V tensioning elements such that rotation of said tensioning oeooe elements varies the tension in said skins.

S 20 In an alternative embodiment, the shell includes a plurality of apertures, the tensioning assembly further S"includes a plurality of connecting elements, and the stabilizing ring is disposed within the shell. In this embodiment, each of the connecting elements extends 25 through a respective one of the apertures without direct contact with the shell and connects a respective one of the tensioning elements to the stabilizing ring. In this way, tension is transferred directly between the skins 5a via the stabilizing ring substantially independently of said shell, thereby permitting substantially undamped vibration of said shell. It should be appreciated that in this embodiment, neither the stabilising ring, nor the connecting elements make contact with the shell at any point, thereby preserving the free floating nature of the tensioning assembly.

Preferred embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:- Figure 1 is a cross-sectional view of the side edge of a drum showing a typical tensioning assembly in accordance with the prior art; Figure 2 is a cross-sectional view similar to Figure 1 showing a drum having a free floating tensioning assembly in accordance with a first embodiment of the S S ft ft ft

I

6 present invention; Figure 3 is a side elevation showing a longitudinal section of the drum of Figure 2; Figure 4 is a sectional view similar to Figure 2 showing a second embodiment of the invention; Figure 5 is a side elevation of a drum similar to that shown in Figure 4; and Figure 6 is a cross-sectional view similar to Figures 2 and 4 showing a third embodiment of the 'oI. 10 invention wherein the stabilising ring is disposed within the shell.

Referring to the drawings, Figure 1 illustrates a typical bass drum in accordance with the prior art. The drum includes a shell comprising an open ended wooden 15 cylinder 10 having smoothly faired but relatively sharp ;edge flanges 11. The drum incorporates a pair of diaphragms or skins 12, each of which incorporates a permanently attached peripheral rim in the form of a relatively rigid hoop 13. The drum further includes a pair of tensioning or loading rings 14 each adapted at one edge to bear against a respective hoop 13, and a plurality of abutment sleeves 20 formed with integral hook flanges 21 positioned at equal intervals around the periphery of each loading ring 14. Each ring 14 is loaded against the associated rim 13 to tension the skin by means of a plurality of tensioning elements, each in the form of a bolt 17 having a wing head 18. The shank of each bolt 17 extends through a respective sleeve 7such that the head 18 of the bolt abuts an adjacent end of the sleeve.

The tension in the skin is transferred via each tensioning bolt 17 to the shell by means of an anchorage block 15. The anchorage blocks 15 are in turn attached directly to the shell by bolts 16 such that the skin is tensioned by engagement of bolts 17 with respective threaded nuts 19. It has been found that these anchorage blocks 15 and other lugs and fittings bolted directly to 10 the drum shell alter the resonant frequencies and damp the vibration of the shell. It is perceived that this adversely affects the sound of the drum.

SFigures 2 and 3, in which corresponding features are denoted by corresponding reference numerals, 15 illustrate a snare drum according to a first embodiment of the present invention. It will be appreciated that the shell, skins and loading ring structures are substantially in accordance with the prior art. However, the drum according to the present invention incorporates a substantially free floating tensioning assembly spaced outwardly from the shell. The tensioning assembly comprises a stabilising ring 32 extending around the shell at mid height, and a plurality of adjustable circumferentially spaced threaded tensioning elements 35. Each tensioning element extends from an outwardly protruding abutment flange 36 associated with a respective loading ring 14 to the central stabilising ring.

8 More particularly, the stabilising ring 32 is generally C-shaped in cross section, having respective upper and lower flanges 38 and 39 extending radially inwardly from an intermediate web portion 40. The ring further incorporates a series of internally threaded fittings 43 spaced circumferentially around each flange.

Each such fitting is adapted for threaded engagement with a corresponding one of the tensioning elements 35. In this way, rotation of the tensioning elements by means of 0 a suitable key engageable with square head 45 effects a corresponding displacement of the loading ring which in *o turn varies the tension in the skins.

Significantly, however, it should be appreciated that unlike prior art drums as exemplified in Figure 1, s15 the free floating tensioning arssembly in accordance with *000 the present invention is disposed to transfer tension directly between the skins, substantially independently of the shell, so that the skins effectively support each other. A consequence of this is that, neglecting #goo*: frictional effects, both skins must always support approximately the same tension, since there is no facility for transferring unbalanced tension reaction forces to the drum shell.

Figure 4 is a sectional view similar to Figure 2 but showing the invention adapted for use with a taller drum. In this embodiment, the stabilising ring is free floating as in Figure 2, but is displaced toward the top skin. The only material difference is that a spacing rod 9 is disposed intermediate each lower threaded tensioning element and the bottom flange 39 of the stabilising ring. Functionally, the tensioning assembly is substantially identical to that shown in Figures 2 and 3.

Figure 5 shows an embodiment similar to that shown in Figure 4, but incorporating a slightly different form of tensioning element and loading ring.

In the embodiment of Figure 6, each corresponding 10 pair of tensioning elements 35 is adjustably inter-connected by an intermediate spacer 52, *incorporating a pair of outwardly protruding side flanges In this embodiment, the stabilising ring 32 is actually disposed within the drum shell, and is connected 15 with the spacers 52 by a series of interconnecting nut and bolt assemblies 57. These assemblies extend between the stabilising ring and the respective flanges 55 on the spacers through oversized apertures 60 formed in the shell. It should be appreciated, however, that in this embodiment neither the stabilising ring 32, nor the interconnecting nut and bolt assemblies 57 make physical contact with the shell at any point, thereby preserving the free floating nature of the tensioning assembly.

Accordingly, the embodiment of Figure 6 works functionally in substantially the same way as those previously described.

In each case, the skins effectively support one another by transferring tension directly through the free 10 floating tensioning assembly. Obviously, the tension forces are reacted at the peripheral edges 11 of the shell such that the entire shell is loaded in axial compression. However, there is no direct mechanism whereby unbalanced skin tensions can be transferred to the side wall of the shell and in that sense, neglecting frictional effects, the tensioning assembly is able to transfer forces directly between the skins, substantially independently of the drum shell. Cymbal stands, brackets 10 and other fittings may conveniently be attached directly to the stabilising ring and thereby also isolated from the drum shell.

Advantageously, this feature enables the shell to vibrate freely, without the damping effects imposed by 15 the mounting blocks, lugs, stands, and other fittings which have hitherto been bolted directly to the shell.

This represents a significant improvement which will be o readily appreciated by those skilled in the art.

A further unexpected benefit has also been 20 discovered. In the prior art, skins are tenaloned by bolts 17 evenly spaced around the drum. One skin is tensioned and roughly tuned to approximately the desired pitch and thereafter fine-tuned. Fine-tuning requires tapping of the skin in positions approximately 1 to 2 inches away from each bolt 17, whereby each position on the skin is tuned to the same note. The entire procedure is then repeated for the other skin. The present invention allows simultaneous rough tuning of the skin 11 tension of both skins. Accordingly, once the first skin has been tuned, the second skin only requires fine-tuning. Furthermore, if it is then desired that the pitch of the drum be altered, only the first skin need be adjusted as the second skin will substantially follow suit in a master/slave arrangement. It will be appreciated that the second skin will maintain its fine-tuning due to the rigidity of the stabilising ring 32.

10 Although the invention has been described with reference to specific examples, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms.

e* es t 6 4

Claims (7)

1. A drum comprising: a shell; a pair of skins disposed at opposite ends of said shell; and a substantially free floating tensioning assembly disposed to stretch said skins over the respective ends of said shell, said tensioning asse-ibly comprising a pair of engagement means each for gripping a periphery of a respective one of said skins, a stabilizing ring disposed in spaced apart relation to said shell intermediate the ends thereof, and a plurality of adjustable spaced apart tensioning elements each connecting a respective one of said engagement means to said stabilizing ring, said stabilizing ring and said tensioning elements being disposed in spaced apart relation to said shell and supported by said engagement means without direct fixture t S"to the shell, such that tension is transferred directly ooeoe between said skins substantially independently of the 20 shell, thereby permitting substantially undamped vibration of the shell.

2. A drum according to claim 1, wherein said shell has an external diameter and each said engagement means comprises a loading ring engaging the periphery of a respective one of said skins, each said loading ring having an internal diameter marginally greater than the corresponding external diameter of an adjacent 13 portion of said shell.

3. A drum according to claim 2, wherein each of said tensioning elements connects a respective one of said loading rings to said stabilizing ring.

4. A drum according to any one of claims 1 to 3, wherein said stabilizing ring is generally C-shaped in cross section, having a pair of spaced apart flanges and a circumferential web portion extending intermediate said pair of flanges, each of said flanges extending radially inwardly toward said shell from said circumferential web portion.

A drum according to claim 4, wherein the stabilizing ring further comprises a series of threaded fittings spaced around each of said flanges, each of said threaded fittings engaging a respective one of any one said tensioning elements such that rotation of said tensioning elements varies the tension in said skins.

6. A drum according to claim 1, wherein said shell includes a plurality of apertures, wherein said 20 tensioning assembly further includes a plurality of connecting elements, and wherein said stabilizing ring is S: disposed within said shell, each of said connecting be elements extending through a respective one of said saw. apertures without direct contact with the shell and be.. 25 connecting a respective one of said tensioning elements to said stabilizing ring such that tension is transferred directly between said skins via said stabilizing ring substantially independently of said shell, thereby fr 4:7~ 14 permitting substantially undamped vibration of said shell.

7. A drum substantially as hereinbefore described with reference to Figures 2 to 5 or Figure 6 of the accompanying drawings. DATED this 3rd day of APRIL, 1995 DONALD ERIC SLEISHMAN Attorney: STUART M. SMITH Fellow Institute of Patent Attorneys of Australia of SHELSTON WATERS i ABSTRACT A drum comprising a shell, a pair of skins (12) disposed at opposite ends of the shell, and substantially free floating tensioning assembly (30) to stretch the skins over the respective ends of the shell. The tensioning assembly comprises respective engagement means adapted to grip the periphery of each skin, a stabilising ring (32) extending around the shell intermediate its ends, and a plurality of adjustable peripherally spaced tensioning elements (35) extending intermediate the 10 respective engagement means and the stabilising ring. The tensioning assembly is disposed to transfer tension S. directly between the skins substantially independently of the shell, thereby facilitating tuning and permitting substantially undamped vibration of the shell. 4. S* 0 S