Loudspeaker terminal

Abstract

 An insulated loudspeaker terminal (1) is disclosed comprising an elongated non-conducting insulator part (5) arranged to be mountable through the wall of a loudspeaker cabinet, a hollow elongated electrically conducting contact part (2) arranged to extend inside the insulator part along a longitudinal axis thereof, the contact part being accessible from both ends of the insulator part, and a non-conducting pressure-applying part (13), which can be releasably and tightly connected to the insulator part in such a way that a stripped end of a loudspeaker cable (18) can be wedged in between the pressure-applying part and the contact part arranged in the insulator part.

Description

[0001] The present invention relates to the field of electrical connectors, more specifically to loudspeaker terminals for connecting loudspeaker cables to loudspeakers and amplifiers.

Background

[0002] Numerous types and brands of loudspeaker terminals are known from the market. Although they come from many different manufacturers, most of them have a number of technical features in common.

[0003] Generally spoken, most loudspeaker terminals a known in the art comprise a threaded rod made from brass, bronze or another alloy with a higher content of copper, such as tellurium copper. The threaded rod is mounted in an amplifier or loudspeaker cabinet by means of two nuts, one on the inside and one on the outside of the cabinet. The loudspeaker cable is fastened in the loudspeaker terminal by means of a third nut, which is typically formed so that it can be tightened with the fingers alone without the need for any tools.

[0004] This typical configuration of loudspeaker terminals entails some disadvantages.

[0005] First of all, it is very difficult to make such terminals from pure metals, such as copper or silver, which is desirable when the terminal is to be used for high-quality audio signals. Contrary to brass and other harder alloys, these metals are generally too soft to be used for the supporting and structural parts of the loudspeaker terminal.

[0006] Secondly, a number of additional parts are needed if a full insulation of the loudspeaker terminal is to be obtained, as is required, for instance, in the European Union.

[0007] US 2005/0130493 A1 discloses an elongated loudspeaker terminal consisting of an elongated non-conducting insulating part, an elongated electrically conducting part arranged within the insulating part, and a non-conducting terminal screw.

[0008] It is an object of the present invention to provide a loudspeaker terminal, which overcomes the disadvantages of the loudspeaker terminals known in the art as mentioned here above.

Brief description of the invention

[0009] The present invention relates to an insulated loudspeaker terminal comprising an elongated non-conducting insulator part arranged to be mountable through the wall of a loudspeaker cabinet, a hollow elongated electrically conducting contact part arranged to extend inside the insulator part along a longitudinal axis thereof, the contact part being accessible from both ends of the insulator part, and a non-conducting pressure-applying part, which can be releasably and tightly connected to the insulator part in such a way that a stripped or terminated end of a loudspeaker cable can be wedged in between the pressure-applying part and the contact part arranged in the insulator part.

[0010] This configuration is advantageous in that it allows for making a loudspeaker terminal from very few parts, which is fully insulated and meets the insulation requirements of all known national and international authorities.

[0011] In an embodiment of the invention, the insulator part comprises an outer thread adapted to fit into an inner thread of a standard nut, by means of which the insulator part can be mounted through a wall of a loudspeaker cabinet.

[0012] In this way, the loudspeaker terminal can be produced and mounted in the cabinet by means of only the three above-mentioned parts and a standard nut.

[0013] In an embodiment of the invention, the pressure-applying part comprises an outer thread adapted to fit into an inner thread of the insulator part.

[0014] Using threads is a simple, well-proven and very reliable way of establishing a releasable connection between two parts.

[0015] In an embodiment of the invention, the pressure-applying part is formed as a bolt, a head of which is formed so that it can be tightly gripped between a pair of fingers, for instance by having an angular shape, such as square or triangular, by having a rough surface or rubber on its sides and/or by being provided with a couple of wings.

[0016] By using a bolt as described above as the pressure-applying part ensures that a high contact pressure and, thus, a good electrical connection between the loudspeaker cable and the contact part can be obtained without the use of any tools.

[0017] In an embodiment of the invention, the thread diameter of the inner thread and the thread of the pressure-applying part is between 10 mm and 30 mm, preferably between 15 mm and 25 mm.

[0018] In an embodiment of the invention, the pitch of the inner thread and the thread of the pressure-applying part is less than 1.5 mm, preferably 1 mm or less.

[0019] Using a relatively large thread diameter and a low pitch increases the strength of the thread and the contact pressure, which can be obtained by using the fingers only.

[0020] In an embodiment of the invention, the inner thread is arranged inside a cylindrical cavity formed in a head of the insulator part formed at a first end thereof for receiving the pressure-applying part, the insulator part further comprising a bore extending from the closed end of the cylindrical cavity through a shaft part of the insulator part along a longitudinal axis thereof to a second end of the insulator part for receiving the contact part, and an opening through a side wall of the insulator part into the cylindrical cavity near the closed end thereof for insertion of the stripped end of a loudspeaker cable.

[0021] Apart from resulting in a desirable design of the loudspeaker terminal, this configuration assures that there is enough room to get a firm grip around the pressure-applying part, which is necessary for obtaining a sufficient contact pressure.

[0022] In an embodiment of the invention, the contact part comprises a tube part, the outer diameter of which corresponds to the inner diameter of the bore, and a flange at its one end, so that the contact part can be mounted and fastened inside the insulator part by inserting it into the bore from the cylindrical cavity until the flange reaches the closed end of the cavity and subsequently squeezing an end of the tube part of the contact part protruding from the second end of the insulator part, thereby deforming the end of the tube part slightly.

[0023] This design results in a small material thickness in the conducting part, i.e. the tube part, of the contact part, which is important for reducing the skin effects occurring in the contact part. Furthermore, the design allows for producing the contact parts by deep drawing, which is a very cost effective production method.

[0024] In an embodiment of the invention, the contact part is made from copper or silver.

[0025] Using copper, preferably pure copper, or silver, preferably pure annealed silver, ensures optimum electrical connections, because these materials have a high conductivity, when compared to other metals.

[0026] In an embodiment of the invention, the insulator part and/or the pressure-applying part is made from plastic materials by injection moulding.

[0027] Plastic moulding is a well-known, reliable and very cheap production method, which may keep the production costs of the relevant parts at a minimum.

Brief description of the figures

[0028] In the following, a few embodiments of the invention will be described in further detail with reference to the figures, in which

fig. 1a

illustrates a perspective view of a contact part for a loudspeaker terminal according to an embodiment of the invention,

fig. 1b

illustrates a perspective view of the same contact part as seen from another angle,

fig. 2a

illustrates a side view of an insulator part for a loudspeaker terminal according to an embodiment of the invention,

fig. 2b

illustrates a cross-sectional view of the same insulator part,

fig. 2c

illustrates a cross-sectional view of the insulator part shown in figs. 2a and 2b with a contact part as shown in figs. 1a and 1b arranged therein,

fig. 3a

illustrates a side view of a pressure-applying part for a loudspeaker terminal according to an embodiment of the invention,

fig. 3b

illustrates an end view of the pressure-applying part shown in fig. 3a,

fig. 4a

illustrates a side view of a pressure-applying part for a loudspeaker terminal according to another embodiment of the invention,

fig. 4b

illustrates an end view of the pressure-applying part shown in fig. 4a,

fig. 5a

illustrates a side view of a pressure-applying part for a loudspeaker terminal according to yet another embodiment of the invention,

fig. 5b

illustrates an end view of the pressure-applying part shown in fig. 5a,

fig. 6a

illustrates a side view of an assembled loudspeaker terminal according to an embodiment of the invention, in which a stripped end of a loudspeaker cable is fastened, and

fig. 6b

illustrates a cross-sectional view of the same assembled loudspeaker with a stripped end of a loudspeaker cable fastened therein.

Detailed description

[0029] Figs. 1a and 1b illustrate perspective views of a contact part 2 for a loudspeaker terminal 1 according to an embodiment of the invention as seen from two different angles.

[0030] The illustrated contact part 2 comprises a tube 3, which at its one end is provided with a flange 4 that extends in a plane substantially perpendicular to the longitudinal axis of the tube 3.

[0031] Preferably, the contact part 2 is made from a metal with a very high conductivity, such as copper or silver.

[0032] The dimensions of the contact part 2 may vary depending on the desired size of the assembled loudspeaker terminal.

[0033] In a preferred embodiment, the inner diameter of the tube 3 is dimensioned to be able to receive and hold the conducting part of a common banana plug.

[0034] The contact parts of most common loudspeaker terminals are made by turning, which is a rather troublesome process if the material is copper or the like. The contact part 2 of the present invention, however, may be made by deep drawing of a piece of metal, which means that the production costs can be kept at a very low level.

[0035] Figs. 2a and 2b illustrate a side view and a cross-sectional view, respectively, of an insulator part 5 for a loudspeaker terminal 1 according to a preferred embodiment of the invention.

[0036] The insulator part 5 comprises a head 6 and a shaft part 7. Inside the head 6 is formed a cylindrical cavity, the wall of which is provided with an inner thread 8. In one side of the head 6 is formed an opening 9 through which the stripped end of a loudspeaker cable 18 may be inserted for being fastened in the loudspeaker terminal 1 (see figs. 6a and 6b).

[0037] From the closed end of the cylindrical cavity, a cylindrical bore 10 extends along the centre axis of the shaft part 7 to the other end of the insulator part 5. The inner diameter of the bore 10 is adapted to fit the outer diameter of the tube 3 of a contact part 2 so that the contact part 2 may be inserted into the bore 10 from the cylindrical cavity formed in the head 6 of the insulator part 5 and extend through the bore 10 to the other end of the insulator part 5.

[0038] Although the tube 3 may be kept in position inside the bore 10 by the friction between the outer surface of the tube 3 and the inner surface of the bore 10, the tube 3 may be further secured by squeezing and thereby slightly deforming an end of the tube 3 protruding from the end of the insulator part 5.

[0039] The insulator part 5 is provided with an outer thread 11 fitting the inner thread of a common nut (not shown). This allows the insulator part 5 to be mounted in the wall of a loudspeaker cabinet or the like by first inserting it through an opening in the wall from the outside thereof until the head 6 reaches the wall, and then mounting a nut on the outer thread 11 on the inside of the wall.

[0040] In the shown embodiment of the insulator part 5, a part near the end opposite the head 6 has been cut away to give sideways access to the bore 10 and, thereby, to the tube 3 of a contact part 2 arranged therein (see fig. 2c). This opens for the opportunity of soldering a cable to the tube 3 inside the cabinet in the wall of which the insulator part 5 is mounted. Another possibility for fastening a cable to the tube 3 is provided by a threaded bore 12, by means of which the end of a screw (not shown) may be tightened against a cable end placed inside the tube 3.

[0041] Fig. 2c illustrates a cross-sectional view of the insulator part 5 shown in figs. 2a and 2b with a contact part 2 as shown in figs. 1a and 1b arranged therein. It is seen how the flange 4 of the contact part 2 is aligned with the opening 9 in the side of the head 6 of the insulator part 5 so that a stripped end of a loudspeaker cable 18 inserted through this opening 9 will be in close contact with the surface of the flange 4.

[0042] Preferably, the insulator part 5 is made from a suitable plastic material by injection moulding, which will ensure a stable and reliable production and at the same time keep the production costs down.

[0043] Figs. 3a and 3b illustrate a side view and an end view, respectively, of a pressure-applying part 13 for a loudspeaker terminal 1 according to an embodiment of the invention.

[0044] The illustrated embodiment is shaped as a bolt with a thread 14 and a head 15. In order to ensure that the pressure-applying part 13 can be tightly gripped between a pair of fingers for applying a sufficient contact pressure when fastening a loudspeaker cable 18 in the loudspeaker terminal 1, the head 15 is formed basically as a square. In addition, the head 15 may be provided with rough side surfaces for further increasing the grip by reducing the risks of the fingers sliding when trying to tighten the loudspeaker terminal 1.

[0045] The fact that the thread 14 of the pressure-applying part 13 is dimensioned to have a relatively large thread diameter and a low pitch increases the strength of the thread and the contact pressure, which can be obtained by using the fingers only.

[0046] Thus, in preferred embodiments, the diameter of the thread 14 of the pressure-applying part 13 and of the inner thread 8 of the insulator part 5 is between 10 mm and 30 mm, preferably between 15 mm and 25 mm, and the pitch of the two threads is less than 1.5 mm, preferably less than 1 mm.

[0047] Figs. 4a and 4b illustrate a side view and an end view, respectively, of a pressure-applying part 13 for a loudspeaker terminal 1 according to an embodiment, which is very similar to the one illustrated in figs. 3a and 3b with the only exception that the head 16 of the pressure-applying part 13 shown in figs. 4a and 4b is triangular rather than square.

[0048] A third embodiment of a pressure-applying part 13 for a loudspeaker terminal 1 according to the invention, in which the head 17 is provided with a couple of wings for increasing the grip, is illustrated in figs. 5a and 5b as a side view and an end view, respectively.

[0049] Just like the insulator part 5, the pressure-applying part 13 is preferably made from a suitable plastic material by injection moulding for production reliability and production cost reasons.

[0050] Figs. 6a and 6b illustrate a side view and a cross-sectional view, respectively, of an assembled loudspeaker terminal 1, in which a stripped end of a loudspeaker cable 18 is fastened. The illustrated loudspeaker terminal 1 consists of an insulator part 5 as illustrated in figs. 2a-2c with a contact part 2 as illustrated in figs. 1a and 1b arranged therein, and a pressure-applying part 13 as illustrated in figs. 3a and 3b.

[0051] Fig. 6b illustrates how the end of the pressure-applying part 13 presses the stripped end of the loudspeaker cable 18 firmly against the flange 4 of the contact part 2, thus ensuring a good and reliable electrical contact between the conductor of the loudspeaker cable 18 and the contact part 2.

[0052] It is worth noting that in this configuration of the loudspeaker terminal 1 the threads 4, 14 are not a part of the signal path as is the case in most known loudspeaker terminals. This fact has a positive influence on the quality of the signal reaching the loudspeaker through the loudspeaker terminal 1.

Reference list

[0053] In the figures, the reference numbers refer to:

1.

Loudspeaker terminal

2.

Contact part

3.

Contact part tube

4.

Contact part flange

5.

Insulator part

6.

Insulator part head

7.

Insulator part shaft

8.

Insulator part inner thread

9.

Insulator part side opening

10.

Insulator part bore

11.

Insulator part outer thread

12.

Threaded bore for fastening of loudspeaker cable

13.

Pressure-applying part

14.

Pressure-applying part thread

15.

Pressure-applying part head - square

16.

Pressure-applying part head - triangular

17.

Pressure-applying part head - winged

18.

Loudspeaker cable

Claims

1. An insulated loudspeaker terminal (1) comprising
an elongated non-conducting insulator part (5) arranged to be mountable through the wall of a loudspeaker cabinet,
an hollow elongated electrically conducting contact part (2) arranged to extend inside the insulator part along a longitudinal axis thereof, the contact part being accessible from both ends of the insulator part, and
a non-conducting pressure-applying part (13), which can be releasably and tightly connected to the insulator part in such a way that a stripped or terminated end of a loudspeaker cable (18) can be wedged in between the pressure-applying part and the contact part arranged in the insulator part.

2. A loudspeaker terminal according to claim 1, wherein the insulator part comprises an outer thread (11) adapted to fit into an inner thread of a standard nut, by means of which the insulator part can be mounted through a wall of a loudspeaker cabinet.

3. A loudspeaker terminal according to claim 1 or 2, wherein the pressure-applying part comprises an outer thread (14) adapted to fit into an inner thread (8) of the insulator part.

4. A loudspeaker terminal according to claim 3, wherein the pressure-applying part is formed as a bolt, a head (15; 16; 17) of which is formed so that it can be tightly gripped between a pair of fingers, for instance by having an angular shape, such as square (15) or triangular (16), by having a rough surface or rubber on its sides and/or by being provided with a couple of wings (17).

5. A loudspeaker terminal according to claim 3 or 4, wherein the thread diameter of the inner thread and the thread of the pressure-applying part is between 10 mm and 30 mm, preferably between 15 mm and 25 mm.

6. A loudspeaker terminal according to any of claims 3-5, wherein the pitch of the inner thread and the thread of the pressure-applying part is less than 1.5 mm, preferably 1 mm or less.

7. A loudspeaker terminal according to any of claims 3-6, wherein the inner thread is arranged inside a cylindrical cavity formed in a head (6) of the insulator part formed at a first end thereof for receiving the pressure-applying part, the insulator part further comprising
a bore (10) extending from the closed end of the cylindrical cavity through a shaft part (7) of the insulator part along a longitudinal axis thereof to a second end of the insulator part for receiving the contact part, and
an opening (9) through a side wall of the insulator part into the cylindrical cavity near the closed end thereof for insertion of the stripped end of a loudspeaker cable.

8. A loudspeaker terminal according to claim 7, wherein the contact part comprises
a tube part (3), the outer diameter of which corresponds to the inner diameter of the bore, and
a flange (4) at its one end,
so that the contact part can be mounted and fastened inside the insulator part by inserting it into the bore from the cylindrical cavity until the flange reaches the closed end of the cavity and subsequently squeezing an end of the tube part of the contact part protruding from the second end of the insulator part, thereby deforming the end of the tube part slightly.

9. A loudspeaker terminal according to any of the preceding claims, wherein the contact part is made from copper or silver.

10. A loudspeaker terminal according to any of the preceding claims, wherein the insulator part and/or the pressure-applying part is made from a plastic material by injection moulding.

Drawing