GB2064999A

GB2064999A - A method of manufacturing membranes for high-fidelity loud speakers

Info

Publication number: GB2064999A
Application number: GB8039918A
Authority: GB
Original assignee: LEVANTE ELECTRONICA AUXILIAR
Current assignee: LEVANTE ELECTRONICA AUXILIAR
Priority date: 1979-12-14
Filing date: 1980-12-12
Publication date: 1981-06-24
Also published as: PT72192A; IT1129940B; ES486914A1; PT72192B; FR2471719A3; IT8068872A0; DE8032983U1; FR2471719B3

Abstract

The disclosed method consists in shaping metal sheet, preferably hard aluminium or beryllium to form a cone 1. The smaller perimeter of the cone obtained in this way has a constituent fold or step 2 at a first reinforcement member, whilst the larger perimeter of the cone is provided with a fold 3 which forms a second reinforcement member. The fold 3 lies in a plane perpendicular to the axis of rotation of the membrane, and a resilient ring is attached to the fold 3 to facilitate vibration of the membrane. <IMAGE>

Description

SPECIFICATION A method of manufacturing membranes for highfidelity loud-speakers The present invention relates to a method of manufacturing membranes for high-fidelity loud-speakers.

it also relates to the membranes so formed. It is additionally concerned with loud-speakers incorporating the membranes as formed.

The membranes of loud-speakers are usually formed as cones which operate by extracting the sounds rebounding off the membrane itself. Consequently, the cardboard membranes which are generally used absorbs the high-pitched timbres and pick up only the low-pitched sounds. It is desirable to improve upon the quality of sound reproduction as of the known membranes.

According to the present invention there is provided a method of manufacturing membranes for high-fidelity loud-speakers, comprising the steps of machining and shaping a metal sheet to obtain the membrane in the form of a cone, forming a first reinforcement member at the end of the cone having the smaller perimeter, said second reinforcement member being in a plane perpendicular to the axis of rotation of the membrane, and joining said second reinforcement member to a resilient ring whereby to facilitate vibration of the membrane.

It is advantageous to use hard aluminium sheet with a minimum frequency of 30 Hz, within the DIN standards which govern the materials and conditions required from them. Hard aluminium must be used, since if the aluminium is soft or annealed, the sound produced by the membrane sounds metallic and in addition the membrane would be weak and readily deformable.

The frequency of loud speakers provided with machined membranes of hard aluminium embraces the entire range of required frequencies, these sound being totally reproduced by the membranes in contrast to other materials which absorb a certain of the frequencies.

It is possible to use other light weight metals which are inert in air such as beryllium.

It is possible to obtain the membranes by means of pneumatic pressure or depression processes.

The invention will now be described further, by way of example, with reference to the accompanying drawings in which; Figure 1 is a front view of a membrane; Figure 2 is a vertical section along the line AB of Figure 1; Figure 3 is a vertical section along the diameter of a further membrane formed using the invention.

In Figure 1 the membrane itself is designated by reference numeral 1, of a first inner-reinforcing member is designated 2 and a second outerreinforcing member is designated 3. The membrane is formed of hard aluminium sheet and has been obtained by machining. The thickness of the material is slight and enables the formation at the outer and inner perimeters of a fold of the material thereby obtaining the first and second reinforcing members.

In this case, the membrane corresponds to a small cone and so only a single fold is sufficient to form said second reinforcing member.

Figure 2 shows how the material of the membrane has been folded on the larger perimeter end to form a fold 3 which in addition to forming said second reinforcement member also forms an encompassing flat surface 4, which is perpendicular to the aretical axis of the membrane. On the flat surface 4 a resilient ring may be mounted, such a ring being usual in membranes in order to facilitate vibration of the membrane.

The membrane 1' shown in Figure 3, may be used in medium or large loud speakers, as opposed to the membrane shown in Figures 1 and 2 which is suitable for small loud speakers. The membrane 1' has a fold 2' at the small perimeter end of the cone and also has a second reinforcement member at the larger perimeter end of the cone. The second reinforcement member comprises an initial fold 5 followed by another fold 6 at right angles to the first fold. The second fold 6 lies in a plane 7 which is perpendicular to the axis of rotation of the membrane, and on this plane a resilient ring may be disposed and secured for assembly on the loud speaker.

It is possible to produce the different parts of the membranes in a variety of materials size and shapes without departing from the scope of the invention.

1. A method of manufacturing membranes or high-fidelity loud-speakers, comprising the steps of machining and shaping a metal sheet to obtain the membrane in the form of a cone, forming a first reinforcement member at the end of the cone having the smaller perimeter, forming a second reinforcement member, at that end of the cone having the larger perimeter, said second reinforcement membey being in a plane perpendicular to the axis of rotation of the membrane, and joining said second reinforcement member to a resilient ring whereby to facilitate vibration of the membrane.

2. A method as claimed in claim 1, which uses hard aluminium as said metal sheet.

3. A method as claimed in claim 1, which uses beryllium as said metal sheet.

4. A method as claimed in any preceding claim, wherein said first reinforcement member is formed as a constituent fold or step.

5. A method as claimed in any preceding claim, wherein said second reinforcement member is formed as a fold.

6. A method as claimed in any of claims 1 to 4 wherein said second reinforcement member is formed by two folds as a rim.

7. A method of manufacturing membranes for high-fidelity loud-speakers substantially as hereinbefore described with references to the accompanying drawings.

8. A membrane for a high-fidelity loud-speaker formed by the method as claimed in any preceding claim.

9. A membrane for a high-fidelity loud-speaker substantially as hereinbefore described with refer

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION A method of manufacturing membranes for highfidelity loud-speakers The present invention relates to a method of manufacturing membranes for high-fidelity loud-speakers. it also relates to the membranes so formed. It is additionally concerned with loud-speakers incorporating the membranes as formed. The membranes of loud-speakers are usually formed as cones which operate by extracting the sounds rebounding off the membrane itself. Consequently, the cardboard membranes which are generally used absorbs the high-pitched timbres and pick up only the low-pitched sounds. It is desirable to improve upon the quality of sound reproduction as of the known membranes. According to the present invention there is provided a method of manufacturing membranes for high-fidelity loud-speakers, comprising the steps of machining and shaping a metal sheet to obtain the membrane in the form of a cone, forming a first reinforcement member at the end of the cone having the smaller perimeter, said second reinforcement member being in a plane perpendicular to the axis of rotation of the membrane, and joining said second reinforcement member to a resilient ring whereby to facilitate vibration of the membrane. It is advantageous to use hard aluminium sheet with a minimum frequency of 30 Hz, within the DIN standards which govern the materials and conditions required from them. Hard aluminium must be used, since if the aluminium is soft or annealed, the sound produced by the membrane sounds metallic and in addition the membrane would be weak and readily deformable. The frequency of loud speakers provided with machined membranes of hard aluminium embraces the entire range of required frequencies, these sound being totally reproduced by the membranes in contrast to other materials which absorb a certain of the frequencies. It is possible to use other light weight metals which are inert in air such as beryllium. It is possible to obtain the membranes by means of pneumatic pressure or depression processes. The invention will now be described further, by way of example, with reference to the accompanying drawings in which; Figure 1 is a front view of a membrane; Figure 2 is a vertical section along the line AB of Figure 1; Figure 3 is a vertical section along the diameter of a further membrane formed using the invention. In Figure 1 the membrane itself is designated by reference numeral 1, of a first inner-reinforcing member is designated 2 and a second outerreinforcing member is designated 3. The membrane is formed of hard aluminium sheet and has been obtained by machining. The thickness of the material is slight and enables the formation at the outer and inner perimeters of a fold of the material thereby obtaining the first and second reinforcing members. In this case, the membrane corresponds to a small cone and so only a single fold is sufficient to form said second reinforcing member. Figure 2 shows how the material of the membrane has been folded on the larger perimeter end to form a fold 3 which in addition to forming said second reinforcement member also forms an encompassing flat surface 4, which is perpendicular to the aretical axis of the membrane. On the flat surface 4 a resilient ring may be mounted, such a ring being usual in membranes in order to facilitate vibration of the membrane. The membrane 1' shown in Figure 3, may be used in medium or large loud speakers, as opposed to the membrane shown in Figures 1 and 2 which is suitable for small loud speakers. The membrane 1' has a fold 2' at the small perimeter end of the cone and also has a second reinforcement member at the larger perimeter end of the cone. The second reinforcement member comprises an initial fold 5 followed by another fold 6 at right angles to the first fold. The second fold 6 lies in a plane 7 which is perpendicular to the axis of rotation of the membrane, and on this plane a resilient ring may be disposed and secured for assembly on the loud speaker. It is possible to produce the different parts of the membranes in a variety of materials size and shapes without departing from the scope of the invention. CLAIMS

3. A method as claimed in claim 1, which uses beryllium as said metal sheet.

9. A membrane for a high-fidelity loud-speaker substantially as hereinbefore described with refer ence to and as illustrated in the accompanying drawings.

10. A loud-speaker having a membrane as claimed in claim 8 or claim 9.