GB2075238A - Drum - Google Patents

Abstract

The drum has a shell (12) and a head (13) and a plurality of clamping members (16). The clamping members, preferably toggle clamps, are adjustable in length so that the drum can be correctly tensioned. After release the clamps can be pivoted away from the head about axes tangential to the shell to release the head. Preferably hook-shaped ends (18) of the clamps engage directly with the hoop (15) of the head. <IMAGE>

Description

SPECIFICATION Drum This invention relates to drums and more particular ly to the means for attaching and tensioning the drum head.

Conventionally a drum has a head with a lapped hoop and this is held in place on the drum and tensioned by a rim and tensioning screws.

The tension screws are secured to the shell of the drum at equiangularly spaced intervals around it circumference and the rim is a specially cast mem ber with fittings at the same spacings for receiving the tensioning screws.

In order to change the head, each tensioning screw must be individually unscrewed for removal of an old or damaged head and then re-screwed to secure the new head and adjusted for correct tensioning. This tends to be a lengthy procedure.

An object of this invention is to provide a drum in which the head is easily changed.

According to the present invention a drum has a plurality of toggle clamps secured at equiangularly spaced intervals around the circumference of its shell and arranged for clamping a standard head to the shell, the clamps being adjustable in length parallel to the axis of the drum for tensioning the head.

The toggle clamps provide a quick release clamp ing mechanism so that a head can be quickly and easily changed. The adjusted length of the clamps will not be disturbed by the unfastening of the clamps and therefore when a new head is fitted and clamped to the shell little re-tuning is required.

Conventional drums have either a narrow rim so that the skin projects above the rim, called a floating head, or a wider rim so that the rim projects above the skin, called a rimmed head.

In the present invention the clamps preferably have ends, e.g. hook-shaped ends, which can direct ly engage the hoop of a standard head, so that where a floating head is desired no rim at all is required, leading to substantial reduction in cost.

The hook-shaped ends of the clamps are alterna tively engageable in circumferentially extending slots in a rim which is formed as a simple hoop made from welded strip or from tube. Such a rim is considerably cheaper than a cast rim with fitments for conventional tensioning screws.

Thus the invention extends to a drum with ten sioning fixing clamps engageable directly with either the hoop of a standard head or with a simple hoop rim.

The drum may have a head at one or each end and may have a floating head at one end and a rimmed head at the other end.

Owing to the facility for quick release and replace ment of a head provided by the clamp fittings, it becomes practicable with a drum having two heads to remove one head to allow stacking of a smaller drum within it for storage or transport purposes.

The toggle clamps provided according to the preferred embodiment of the invention protrude outwards from the shell for approximately 1.9 cms which is less than the protrusion of the standard screw tensioners.

Conventionally a set of drums comprises drums having shell diameters which differ from the diameters of adjacent drums of the set by approximately 5 cms, e.g. a set of tomtom drums of 20 cms, 25 cms, 30 cms, 35 cms, 40 cms and 45 cms, is common. conventionally a drum is fitted in its interior with a tone control member and on its exterior with a holder for connecting the drum to a stand or larger diameter drum. These fittings conventionally project more than 2.5 cms from the shell.

According to another feature of the invention the holder and/or tone control fitments and/or other fitments are designed to protrude from the shell a distance less than half the standard dimensional difference between adjacent drums of a set. In the present instance these fittings project less than 2.5 cms from the shell. With such an arrangement a set of drums can stack one inside the next adjacent larger drum of the set. A fibre tubular shield will normally be provided between adjacent drums and the heads will be separately stacked in a separate case with shields between them.

Two embodiments of the drum, in accordance with the invention, will now be described, by way of example only, with reference to the accompanying drawings of which: Figure lisa side view of a drum with a single floating head, Figure 2 is a side view of a double-head drum with rims, and Figures 3A and B are side and front views of one form of toggle clamp on an enlarged scale, in the open position.

Referring to Figure 1, a drum has a cylindrical shell 12 in this case made from tube or sheet plastics material. The drum is provided with a standard head 13 consisting of a skin 14, which may be of plastics material, and a metal hoop 15 round which the edge of the skin is wrapped to form an integral head. A set of toggle clamps 16 of known form are equiangularly spaced round the circumference of the shell and screwed to the shell. In this example there are eight clamps for a 30 cms diameter drum but this will differ with the size of drum. Each toggle clamp has a clamping arm 17 with a hooked end 18, which end directly engages over the hoop 15 of the head. To release the head the toggle arms 20 of the clamps are pulled down allowing the hooks to be raised and the head lifted off.A new head can be placed on the shell, the hooks engaged and the toggle arms raised in less than one minute.

Each clamping arm is formed with a screw thread 21 engaging a thread on the clamp base 22 so that it can be rotated to effectively change the length of the clamping arm in the direction parallel to the axis of the drum. This allows for tensioning and thus tuning of the head. The effective length will not vary during an unclamping and re-clamping operation so little re-tuning is required after removal and replacement of a head. The drum of Figure 1 has an open base with an edging 23.

The drum of Figure 2 is similar to that of Figure 1 except that it has a head at each end, thus requiring a set of toggle clamps 16 adjacent each end, and it has a rimmed head.

The rim 24 for each end is formed as a simple hoop from welded strip or tube metal with no fitments or protrusions but with a set of circumferentially extending spaced slots 25 for receiving the hooked ends of the clamping arms. In this example the rim is of substantially the same diameter as the head hoop, 1.9 cms deep and of 0.3 cms thick steel.

In an alternative arrangement the hooked ends could engage over the top of the rim. Rubber dampers 26 may be provided to prevent the toggle arms vibrating in use.

The tone control and the holder for fixing the drums to a base drum or stand are not shown but project from the shell of the drum for less than 2.5 cms to enable all the drums of a set to stack one inside the other.

Figure 3 shows one form of toggle clamp but it will be appreciated that other designs of quick release clamp could be used.

Claims (10)

1. A drum having a shell and a head and a plurality of clamping members secured at substantially equi-angularly spaced intervals to the outer surface of the shell, the clamping members being adjustable in length parallel to the axis of the shell for tensioning the head and each having its clamping portion pivotable about an axis normal to the axis of the shell between the clamping position and a position away from the head to allow removal of the head.

2. A drum according to Claim 1 in which the clamping members are toggle clamps.

3. A drum according to Claim 1 or Claim 2 in which the adjusted length of the clamping members is not disturbed by fastening and unfastening of the clamping portions.

4. A drum according to any of Claims 1 - 3 in which the clamping members have hook-shaped ends arranged to directly engage the hoop of the drum.

5. A drum according to any of Claims 1 - 4 having a ring formed as a simple hoop from welded strip or tube material.

6. A drum according to any of Claims 1 - 5 having a head at each end, each head having associated clamping members in accordance with the preceding claims.

7. A drum according to any of Claims 1 - 6 in which the clamping members project less than 2.5 cms from the outer surface of the shell.

8. A drum according to any of Claims 1 - 7 including a turn control member, the fittings of which are adjustable so that it projects inwards less than 2.5 cms from the inner surface of the shell.

9. A drum according to any of Claims 1 - 8 in which the shell is made of plastics material.

10. A drum substantially as described herein with reference to the accompanying drawings.