GB2113888A

GB2113888A - Musical drum

Info

Publication number: GB2113888A
Application number: GB08132424A
Authority: GB
Inventors: Porta Clifford Anthony Della
Original assignee: Premier Drum Co Ltd
Current assignee: Premier Drum Co Ltd
Priority date: 1981-10-28
Filing date: 1981-10-28
Publication date: 1983-08-10

Abstract

A drum head for a musical drum consisting of at least two layers 10, 12 arranged in overlapping relationship with a spacer means 14 between layers spacing them apart. <IMAGE>

Description

SPECIFICATION Musical drums The present invention relates both to a drum head for a musical drum and also to a musical drum.

A conventional musical drum consists of a generally cylindrical body shell closed at one or both ends by a tensioned head or heads, commonly known as the drum skin or skins. The body shell is conventionally of a sheet of a pliabie but rigid material, for example plywood, or alternatively from thin sheet metal which is rolled into cylindrical form and secured at its abutting edges by welding or cementing for example. More recently, the body shell has been moulded from a plastics material.

The head or skin is normally of a film of synthetic material such as polyethylene terephthalate. In use, the skin vibrates when struck with a drum stick or the like, the amplitude of the vibration induced in the head being dependent on the force of which the head is struck.

It has been proposed to adhere a disc of polyvinyl chloride for example to the geometric centre of the drum head to dampen out harmonic frequencies induced in the drum skin. Such discs however not only dampen out the harmonic frequencies but also the antinode which develops at the centre of the drum head.

In the applicants prior UK patent No. 1583781 there is described and claimed a drum head for a musical drum said head having a circular disc adhered to the geometric centre thereof, the disc having a window at a central portion thereof which serves to permit an antinode to develop in vibrations induced in the drum head when the drum is struck.

In accordance with the broadest aspect of the present invention is has now been found advantageous to provide a drum head for a musical drum comprising at least two layers arranged in overlapping relationship, at least one region of adjacent layers being spaced apart by spacer means disposed between the or each layer.

The spacing between the layers forms an air pocket thus permitting vibrations to develop in each layer.

In a preferred embodiment of the invention the head embodies two layers and the spacer means comprises a circular disc having a window at a central portion thereof. The preferred spacer means therefore corresponds in shape with the circular disc described in the applicants above referred to earlier UK patent.

The invention will now be described further by way of example with reference to the accompanying drawing the single figure of which is a cross sectional view of a drum head in accordance with a preferred embodiment of the invention.

The head illustrated consists of two layers 1 0, 12 each of afilm of synthetic material such as polyethylene terephthalate. The thickness of each layer is approximately 5 thousandths of an inch, that is roughly half the thickness of a single layer head.

A spacer in the form of an annular disc 14 of polyvinyl chloride is disposed between and at the approximate centre of the two discs to space them apart. If desired, the spacer can be adhered to one or both of the layers 10, 1 2.

Alternatively, the spacer may be of a metal or embody a metal thus providing added reinforcement to the area where the head is struck. Where it is desired to produce a "velum" sound the spacer may consist of a foraminous and/or cellular material for example, a woven or knitted fabric, leather or wood. Alternatively again, the entire upper layer 10 can be of the foraminous or cellular material, for example, the upper layer may consist of a woven fabric.

When the drum head is struck those areas of the heads which are in direct contact with the spacer vibrate in unison. Separate vibrations are able to develop in those parts of the layers 10, 12 of the head which are held in spaced apart relationship by the disc 14. Hence, although vibrations are developed initially in the upper layer 10, sympathetic vibrations are developed in the lower layer 12,-derived at least in part from vibrations induced in the layer 1 2 where the two layers contact the spacer. In the drawing, the parts concerned are designated generally as 1 6 and 18, being respectively the centre of the disc 1 4 and the area around the outer circumference of the disc.

It is preferred that at least upper layer 10 is of a transparent or translucent material to permit the disc 14 and the lower layer 12 to be viewed therethrough. In the drawing, the disc is coloured black, but any other colour may be employed.

Moreover, whereas in the described embodiment the two layers 10, 1 2 are described as being of equal thickness, the layers may be of unequal thickness in dependence upon the sound which the drum is required to produce.

It is believed that the improved sound produced by the drum of the invention arises at least in part from the fact that the two layers of the head lessen the number of normally audible harmonic vibrations present.

1. A drum head for a musical drum comprising at least two layers arranged in overlapping relationship and a spacer means located between said layers for spacing apart a region of said layers.

2. A drum head as claimed in claim 1 in which said spacer means has a window centrally of said spacer means.

3. A drum head as claimed in claim 1 or 2 in which said spacer means is annular in shape.

4. A drum head as claimed in claim 1,2 or 3 in which the spacer means is made of metal, material embodying metal, plastics material, foraminous or cellular material.

5. A drum head as claimed in claim 4 in which

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Musical drums The present invention relates both to a drum head for a musical drum and also to a musical drum. A conventional musical drum consists of a generally cylindrical body shell closed at one or both ends by a tensioned head or heads, commonly known as the drum skin or skins. The body shell is conventionally of a sheet of a pliabie but rigid material, for example plywood, or alternatively from thin sheet metal which is rolled into cylindrical form and secured at its abutting edges by welding or cementing for example. More recently, the body shell has been moulded from a plastics material. The head or skin is normally of a film of synthetic material such as polyethylene terephthalate. In use, the skin vibrates when struck with a drum stick or the like, the amplitude of the vibration induced in the head being dependent on the force of which the head is struck. It has been proposed to adhere a disc of polyvinyl chloride for example to the geometric centre of the drum head to dampen out harmonic frequencies induced in the drum skin. Such discs however not only dampen out the harmonic frequencies but also the antinode which develops at the centre of the drum head. In the applicants prior UK patent No. 1583781 there is described and claimed a drum head for a musical drum said head having a circular disc adhered to the geometric centre thereof, the disc having a window at a central portion thereof which serves to permit an antinode to develop in vibrations induced in the drum head when the drum is struck. In accordance with the broadest aspect of the present invention is has now been found advantageous to provide a drum head for a musical drum comprising at least two layers arranged in overlapping relationship, at least one region of adjacent layers being spaced apart by spacer means disposed between the or each layer. The spacing between the layers forms an air pocket thus permitting vibrations to develop in each layer. In a preferred embodiment of the invention the head embodies two layers and the spacer means comprises a circular disc having a window at a central portion thereof. The preferred spacer means therefore corresponds in shape with the circular disc described in the applicants above referred to earlier UK patent. The invention will now be described further by way of example with reference to the accompanying drawing the single figure of which is a cross sectional view of a drum head in accordance with a preferred embodiment of the invention. The head illustrated consists of two layers 1 0, 12 each of afilm of synthetic material such as polyethylene terephthalate. The thickness of each layer is approximately 5 thousandths of an inch, that is roughly half the thickness of a single layer head. A spacer in the form of an annular disc 14 of polyvinyl chloride is disposed between and at the approximate centre of the two discs to space them apart. If desired, the spacer can be adhered to one or both of the layers 10, 1 2. Alternatively, the spacer may be of a metal or embody a metal thus providing added reinforcement to the area where the head is struck. Where it is desired to produce a "velum" sound the spacer may consist of a foraminous and/or cellular material for example, a woven or knitted fabric, leather or wood. Alternatively again, the entire upper layer 10 can be of the foraminous or cellular material, for example, the upper layer may consist of a woven fabric. When the drum head is struck those areas of the heads which are in direct contact with the spacer vibrate in unison. Separate vibrations are able to develop in those parts of the layers 10, 12 of the head which are held in spaced apart relationship by the disc 14. Hence, although vibrations are developed initially in the upper layer 10, sympathetic vibrations are developed in the lower layer 12,-derived at least in part from vibrations induced in the layer 1 2 where the two layers contact the spacer. In the drawing, the parts concerned are designated generally as 1 6 and 18, being respectively the centre of the disc 1 4 and the area around the outer circumference of the disc. It is preferred that at least upper layer 10 is of a transparent or translucent material to permit the disc 14 and the lower layer 12 to be viewed therethrough. In the drawing, the disc is coloured black, but any other colour may be employed. Moreover, whereas in the described embodiment the two layers 10, 1 2 are described as being of equal thickness, the layers may be of unequal thickness in dependence upon the sound which the drum is required to produce. It is believed that the improved sound produced by the drum of the invention arises at least in part from the fact that the two layers of the head lessen the number of normally audible harmonic vibrations present. CLAIMS

5. A drum head as claimed in claim 4 in which said spacer means is made of polyvinyl chloride or leather or wood or a woven or knitted fabric.

6. A drum head as claimed in any one of the preceding claims in which the spacer means is adhered to at least one of said layers.

7. A drum head as claimed in any one of the preceding claims in which each said layer is substantially 0.005 inch thick.

8. A drum head as claimed in any one of claims 1 to 6 said layers are of different thickness.

9. A drum head as claimed in any one of the preceding claims in which the upper of said layers is made of foraminous or cellular material.

10. A drum head for a musical drum substantially as herein described with reference to and as illustrated in the accompanying drawing.

11. A musical drum whenever provided with a drum head as claimed in claim 1.