GB2313468A

GB2313468A - Drum head tensioning

Info

Publication number: GB2313468A
Application number: GB9610795A
Authority: GB
Inventors: Ivor David Arbiter
Original assignee: Arbiter Group PLC
Current assignee: Arbiter Group PLC
Priority date: 1996-05-22
Filing date: 1996-05-22
Publication date: 1997-11-26
Also published as: GB9610795D0

Abstract

A drum comprises drum shell 11, drum head 12, counter-hoop 13 and shell hoop 15. Drum skin 17 extends over the open end of the drum shell and has a circumferential bead 18. Counter-hoop 13 has a downwardly and outwardly extending flange 19 which bears on the bead. Shell hoop 15 has a rim 16 which extends upwardly and outwardly. An adjustable clamp ring 21 engages flange 19 of the counter-hoop 13 and rim 16 of the shell hoop 15 through correspondingly inclined portions 23, 24. When the clamp ring is tightened, counter-hoop 13 is forced downwards, thereby tightening the skin 17. The clamp ring is in the form of a breached circular band with two ends, such that moving the two ends relative to one another circumferentially, preferably by means of a screw thread arrangement (figs. 3 and 4), varies the effective circumference of the ring, thereby tightening it.

Description

DRUM The present invention relates to drums, that is to say percussion instruments, such as snare drums, tomtoms, bass drums, tympanis, and the like. The invention is particularly concerned with the tuning of drum heads.

In conventional drums, the skin of the drum head is stretched over the open end of a cylindrical drum shell and is held in position by means of a counter-hoop which bears on the rim of the head. The skin is tensioned by means of tensioning bolts which act on the counter-hoop and engage tapped fittings fixed to the drum shell. When these bolts are tightened, the counter-hoop is urged against the rim, thus tensioning the skin.

In order to ensure that the skin is evenly tensioned and is therefore "tuned", it is necessary to adjust minutely each of the bolts, which are usually at least six or eight in number. This procedure is complicated by the fact that when one bolt is adjusted it has differing effects on the tension in the skin produced by the other bolts, making tuning a very time consuming and skilled operation.

Two related proposals which seek to address this disadvantage are described in British Patent Nos. 1488167 and 1558045. In the first of these references, the counter-hoop has a series of circumferentially located inclined slides which each engage a pair of rollers which are fixed to the shell. The rollers in each pair are offset to define an angle of inclination which corresponds to the inclination of the slides. Thus, as the counter-hoop is rotated in one sense, the slides and rollers engage, drawing the counter hoop down against the head rim and so tensioning the head. Rotation in the other sense has the opposite effect. The counter-hoop is rotated by means of a rack which is fixed to the counterhoop, and a pinion fixed to the shell; as the pinion is rotated, the rack is driven circumferentially. The arrangement shown in the second reference is very similar except that the rollers are replaced by inclined nylon blocks.

A disadvantage of these arrangements is that even tensioning is still difficult to achieve in practice, partly due to unevenness and imperfections in the heads and partly due to the difficulties in attaching the rollers or blocks accurately to the shell.

This problem is addressed in the present Applicant's co-pending application No. 9511862.6 which provides a drum comprising:- a drum shell; a drum head having a skin extending over an open end of the shell and a circumferential hoop lying outside the open end of the shell; a counter-hoop lying over the head hoop, the counter-hoop having a plurality of circumferentiallyspaced inwardly-facing cam followers; and means for rotating the counter-hoop about the drum axis with respect to the drum shell; the drum also including a shell ring attached to and surrounding the shell in the vicinity of the open end and a compression ring located between the counter-hoop and the head hoop; the shell ring having a plurality of circumferentially-spaced, outwardly facing cam members which respectively engage the counter-hoop cam followers.

However, a simpler arrangement may be advantageous in certain circumstances. It is therefore an object of the present invention to provide a drum in which the drum skin can be tensioned and tuned in a single operation and which is simpler in construction than existing designs.

According to the invention, there is provided a drum comprising: a drum shell, a drum head having a skin extending over an open end of the shell and a circumferential hoop lying outside the open end of the shell; a counter-hoop lying over the head hoop; and a shell ring attached to and surrounding the shell in the vicinity of the open end; the counter-hoop and the shell hoop each having a radially outwardly extending portion, the outwardly extending portions being such that the counter-hoop portion is inclined downwards and/or the shell hoop portion is inclined upwards; the drum also including a clamp ring which surrounds the drum shell and engages the two outwardly extending portions, the clamp ring being capable of radial expansion and contraction.

Thus, as the clamp ring contracts, it exerts an inward compression force which tends to draw the counterhoop towards the shell hoop which tensions the drum skin.

The counter-hoop bears directly on the head hoop.

However, optionally, a compression ring may be located between the counter-hoop and the head hoop. The location of the shell ring can be achieved with considerable accuracy, thus minimising the likelihood of uneven forces being applied to the head hoop by the counter-hoop.

The outwardly extending portion of the counter-hoop is preferably a continuous flange. The shell hoop may be discontinuous and may even be constituted by circumferentially spaced blocks or bosses, however, the shell hoop is preferably a continuous ring and the outwardly extending portion is preferably a continuous flange. The shell hoop may be screwed, bolted or glued to the shell and/or may be let into a channel formed in the shell. An outer clamp ring (such as a hose-clip) may be used additionally to hold the shell hoop in place.

Preferably, the counter-hoop is of stainless steel which is preferably polished. The compression ring (if included) may be of any suitable deformable material and is preferably also resilient; a convenient material is NEOPRENE (TM.).

The clamp ring is preferably made of a strong nonelastic but resilient material such as steel. It preferably includes radially inwardly extending rails which are inclined in a way which corresponds to any inclination of the outwardly extending portions of the counter-hoop and shell hoop. Preferably, the inclinations are symmetrical.

The clamp ring may be radially contractable by reducing its circumferential length. This may be achieved by the clamp ring being in the form of a breached circular band with two ends; by moving the ends relative to each other circumferentially, the effective circumference of the clamp ring can be varied. In order to control this adjustment, the clamp ring may have a screw thread arrangement spanning the breach. Preferably a first end of the clamp ring on one side of the breach has an internally threaded member, while the second end of the clamp ring on the other side of the breach has a bush. A bolt may then pass through the bush and into the threaded member, so that as the bolt is rotated, it is drawn through the threaded member and the bolt head will bear against the bush. Continued rotation will move the bush towards the threaded member and so tighten the clamp ring.

Preferably, the clamp ring is hinged in a position remote from the breach, conveniently at a position opposite the breach. This arrangement will allow the clamp ring to be fitted in position more readily.

The invention may also be particularly applicable to tympanis. The counter-hoop could be reduced in height in order that it should not protrude above the level of the drum skin. In order to tune the instrument, a flexible drive may be provided, connected to a foot pedal. The drive would then also engage the bolt. As the foot pedal is operated, the bolt is tightened or loosened and the pitch of the skin is adjusted. Alternatively, an electrical drive operated by the foot pedal could be employed to rotate the bolt.

The invention can also be applied to bongo drums and other drums played by the hands. Again, the counter-hoop would be reduced in height to avoid a rim protruding above the level of the skin.

The invention may be carried into practice in various ways and one embodiment will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 is a partial vertical section through one wall of a drum in accordance with the present invention; Figure 2 is a view similar to Figure 1 showing the drum head tensioned; Figure 3 is a plan view of the clamp ring tensioning mechanism; Figure 4 is a side view of the clamp ring tensioning mechanism; and Figure 5 is a plan view of the clamp ring hinge.

As shown in Figures 1 and 2, the drum comprises a drum shell 11, a drum head 12, a counter-hoop 13, and a shell hoop 15. The drum shell 11 is of standard laminated resin bonded hardwood construction. It is cylindrical and open ended. The shell hoop 15 is of polished stainless steel and is rigidly attached around the top of the shell 11. The shell hoop has a rim 16 which extends upwardly and outwardly.

The head 12 comprises a skin 17 and a flesh hoop or bead 18 at its periphery. The bead 18 is located outside the drum shell 11 so that the skin 17 stretches over the open end. The counter-hoop 13 is of polished stainless steel and has a downwardly and outwardly extending flange 19. The flange 19 of the counter-hoop 13 bears on the bead 18.

The counter-hoop 13 is held in position by a clamp ring 21. The clamp ring 21 is a steel band with overlapping ends, and a C-shaped cross-section comprising a generally flat spine 22 with upper and lower skirts 23,24. The skirts 23,24 extend inwardly and diverge with inclinations corresponding to those of the rim 16 and flange 19. Thus, when in position, the upper skirt 23 fits over the flange 19 on the counter-hoop 13 and the lower skirt 24 fits beneath the shell hoop rim 16.

As shown in Figures 3, 4 and 5, the clamp ring 21 has a breach 41 defining two ends 42,43 and, diametrically opposite, a hinge 44. A threaded nut 45 is attached to one end 42 of the clamp ring 21 and a bush 46 is attached tc the other end 43. A threaded bolt 47 with a head 48 passes through the bush 46 and engages the nut 45. The bolt head 48 has a hexagonal portion 49 and a through-hole 51 passing through the head at right angles to the bolt axis.

In use, when the components are assembled, the head 12 is placed over the open end of the shell 11 and the counter-hoop 13 is located on the bead 18. The clamp ring 21 is then located outside the counter-hoop 13 and shell ring 15. This is facilitated by the hinge 44, which allows the clamp ring 21 to open. The bolt 47 is then tightened (either by the hexagonal head 49 or by a metal rod or the like passing through the through-hole 51) and the clamp ring 21 is constricted. As the clamp ring 21 constricts, the skirts 23,24 engage the flange 19 and rim 16, so locating the counter-hoop 13. As the clamp ring 21 is tightened further, the counter-hoop 13 is drawn down by the dual camming action of the two skirts 23,24.

This in turn exerts a downward pressure on the bead 18 which stretches the skin 17 evenly over the rim of the shell 11. To remove the skin 12, it is simply necessary to reverse the operation.

It has been found in practice that with this arrangement it is possible to achieve a downward movement of the counter-hoop 13 of up to 6 mm, from the point at which the counter-hoop 13 engages the bead 18. This is more than sufficient to enable the drum skin 17 to be tuned.

Claims

Claims:

1. A drum comprising: a drum shell, a drum head having a skin extending over an open end of the shell and a circumferential hoop lying outside the open end of the shell; a counter-hoop lying over the head hoop; and a shell ring attached to and surrounding the shell in the vicinity of the open end; the counter-hoop and the shell hoop each having a radially outwardly extending portion, the outwardly extending portions being such that the counter-hoop portion is inclined downwards and/or the shell hoop portion is inclined upwards; the drum also including a clamp ring which surrounds the drum shell and engages the two outwardly extending portions, the clamp ring being capable of radial expansion and contraction.

2. A drum as claimed in Claim 1 in which the outwardly extending portion of the counter-hoop is a continuous flange.

3. A drum as claimed in Claim 1 or Claim 2 in which the shell hoop is a continuous ring and the outwardly extending portion is a continuous flange.

4. A drum as claimed in any preceding Claim in which the shell hoop is let into a channel formed in the shell.

5. A drum as claimed in any preceding Claim in which the counter-hoop is of stainless steel.

6. A drum as claimed in any preceding Claim in which the clamp ring includes radially inwardly extending rails which are inclined in a way which corresponds to the inclination of the outwardly extending portion of the counter-hoop and shell hoop.

7. A drum as claimed in any preceding Claim in which the clamp ring is in the form of a breached circular band with two ends, the two ends being movable relative to each other in a circumferential sense whereby the circumference of the clamp ring can be varied.

8. A drum as claimed in Claim 7 in which the clamp ring includes a screw thread arrangement spanning the breach.

9. A drum as claimed in Claim 8 in which a first end of the clamp ring on one side of the breach has an internally threaded member while the second end of the clamp ring on the other side of the breach has a bush, and a bolt passes through the bush and into the threaded member.

10. A drum as claimed in any of Claims 7 to 9 in which the clamp ring is hinged in a position remote from the breach.

11. A drum as claimed in any preceding Claim in which the drum is a timpani and includes a tuning mechanism comprising a flexible drive connected to a foot pedal.