Speaker box comprising a housing made of monoblock plastic material

Description

[0001] The present invention relates to an acoustic enclosure comprising: a metal frame, a plastic shell fixed to the frame, the shell defining at least two openings, and at least two loudspeakers arranged head to tail along a transverse axis, the two loudspeakers extending respectively across the two openings.

[0002] In a compact loudspeaker, the drivers, especially the bass drivers, are relatively large components. They are arranged head to tail so that the movements of their membranes do not create vibrations that could cause the loudspeaker to move unexpectedly.

[0003] Due to their large volume and this relative position, the speakers are fixed to separate portions of the shell, for example by screws. Then, the separate portions are assembled together to form the shell and place the two speakers in their head-to-tail position.

[0004] As a result, the shell has assembly marks, such as joints, which are visible to the eye or touch by a user of the loudspeaker, especially when the latter is compact. Such assembly marks are sometimes considered unsightly, as they detract from the smooth appearance of the loudspeaker.

[0005] Mr. Jan Selley's article: "Naim Mu-So Qb Review. Can Naim make their philosophy work at 600?", dated January 30, 2016, XP055589715, retrieved from the Internet: URL:https: / / www.avforums.com / review / naim-mu-so-qb-review.12327 describes a generally cubic-shaped loudspeaker enclosure. The enclosure comprises a shell shown on page 9, and a back plate shown on page 8. The plate closes an access opening in the shell, which forms a chassis (page 3, middle of the page).

[0006] US 4,805,221 discloses two speakers placed head to tail to limit the vibrations of the cabinet of an acoustic enclosure.

[0007] Mr. Michael Brown's article: "Devialet Phantom review: Forget everything you thought you knew about speaker technology", November 13, 2015, XP055589418, retrieved from the Internet: URL:https: / / www.techhive.com / article / 3004548 / devialet-phantom-review-forget-everything-you-thought-you-knew-about-speaker-technology.html describes an acoustic speaker comprising a two-part shell.

[0008] FR 3 012 716 A1 relates to the acoustic enclosure described in the article by Mr. Michael Brown.

[0009] CN 207 910 991 U describes an acoustic enclosure of generally tubular shape.

[0010] The aim of the invention is to propose an acoustic enclosure with a smoother appearance, generally perceived as more aesthetic by a user.

[0011] To this end, the invention relates to an acoustic enclosure according to claim 1.

[0012] According to particular embodiments, the acoustic enclosure comprises one or more of the characteristics corresponding to claims 2 to 9, taken in isolation or in all technically possible combinations.

[0013] The invention will be better understood on reading the following description, given solely by way of example and with reference to the appended drawings, in which: there figure 1 is a perspective view of an acoustic enclosure according to the invention, the figure 2 is a perspective view of the acoustic enclosure shown in the figure 1 , exploded along a longitudinal axis, the loudspeakers and other internal elements of the acoustic enclosure not being shown, the figure 3 is a side view of the enclosure shell shown in the figures 1 And 2 , there figure 4 is a front view of the loudspeaker shown in the figures 1 And2 , there figure 5 is a sectional view of the hull shown in the figures 1 à 4 according to a plane containing the longitudinal axis of the acoustic enclosure and a transverse axis defined by the loudspeakers, the figure 6 is a detailed view of the hull and frame shown in the figures 1 And 2 , in section along the same plane as that of the figure 5 , and the figure 7 is a front view of one of the inserts present in the hull shown in the figures 1 à 6 .

[0014] In reference to the figures 1 And 2 , an acoustic enclosure 1 according to the invention is described.

[0015] The acoustic speaker 1 is for example an active speaker, that is to say that it comprises an audio signal reader and an amplifier (not shown, just as other electrical or electronic elements of the speaker that are not relevant to explaining the invention are not shown).

[0016] In the example shown, the acoustic enclosure rests on a preferably horizontal surface S. The acoustic enclosure has, for example, a generally oblong shape along a longitudinal axis L, which advantageously forms an angle with the surface S, as visible in the figure 3 The acoustic enclosure thus has a front part 3 and a rear part 5 along the longitudinal axis L, the front part being higher than the rear part relative to the surface S.

[0017] The acoustic enclosure comprises a metal frame 7, and a plastic shell 9 fixed on the frame, the shell defining at least two openings 11A and 11B. The acoustic enclosure comprises two bass loudspeakers 13A and 13B (only one of which is visible on the figure 1 ) arranged head to tail along a transverse axis T, for example perpendicular to the longitudinal axis L. The two loudspeakers 13A and 13B extend respectively across the openings 11A and 11B.

[0018] By "bass speaker" is meant a speaker adapted to diffuse sound waves of frequencies lower than 1000 Hz, preferably lower than 500 Hz, even more preferably lower than 150 Hz.

[0019] The acoustic enclosure 1 advantageously comprises a third loudspeaker (not shown), for example fixed in a housing 15 formed by the shell 9 in the front part 3.

[0020] The acoustic enclosure comprises two metal inserts 17A and 17B, advantageously symmetrical to each other with respect to a plane P perpendicular to the transverse axis T and containing the longitudinal axis L, and one of which is shown in the figure 7 .

[0021] The acoustic enclosure has a symmetrical external appearance with respect to this plane P.

[0022] The third loudspeaker (not shown) located in the housing 15 is for example centered on the longitudinal axis L. Advantageously, it is suitable for broadcasting sound waves of frequencies ranging from 300 Hz to 20 kHz, or even from 150 Hz to 40 kHz.

[0023] The frame 7 is advantageously a casting, for example made of aluminum. The frame 7 comprises an external part 19 forming the rear part 5 of the acoustic enclosure, and an internal part 21 integral with the external part and extending along the plane P.

[0024] The external part 19 and the shell 9 together define an internal volume 23 ( figure 2 ) of the acoustic enclosure.

[0025] The outer portion 19 comprises a rear portion 25 comprising a plurality of fins 27 ( figure 6 ) adapted to evacuate the heat released in the internal volume 23 during operation of the acoustic enclosure.

[0026] The external part 19 also comprises a sole 29 which extends under the loudspeakers 13A, 13B along the longitudinal axis L from the rear portion 25.

[0027] The external part 19 of the frame and the shell 9 are adapted to fit into each other along the longitudinal axis L.

[0028] When viewed along the transverse axis T, the external part 19 advantageously has a general “U” shape.

[0029] One of the branches of the “U” is formed by the sole 29 and is for example larger than the other branch.

[0030] The fins 27 are for example parallel to the plane P, and advantageously delimited by a spherical envelope 31 ( figure 6 ) of the same curvature as the front part 3 of the acoustic enclosure.

[0031] The external part 19 has a curvilinear edge 33 defining a groove 35 in which a seal 37 forming a loop is arranged.

[0032] The curvilinear edge 33 is adjacent to a curvilinear edge 39 of the shell 9, the seal 37 being disposed between the two curvilinear edges 33 and 39.

[0033] The internal part 21 forms a support for fixing the two loudspeakers 13A, 13B and the shell 9. The internal part 21 defines for example an orifice 41 ( figure 2 ) adapted to fix the loudspeaker 11B on the internal part 21. For example, a screw (not shown) is screwed into the loudspeaker 11B through the hole 41.

[0034] The internal part 21 defines a surface 43 on which the loudspeaker 11A is for example glued.

[0035] The shell 9 is a single-piece. By "single-piece" is meant that the shell 9 is a single piece; it does not include parts attached to each other by mechanical means. The shell 9 is advantageously fixed to the internal part 21 by a single screw / nut system, comprising a stud 45 fixed to the internal part, and a nut 47 screwed onto this stud. One or more washers 49 are threaded onto the stud 45 between the shell 9 and the internal part 21 to adjust the axial spacing between these two parts.

[0036] The shell 9 comprises, successively along the longitudinal axis L, a front part 51 forming a portion of a sphere, an intermediate part 53 forming a portion of a cylinder, and two rear walls 55A, 55B located longitudinally at the rear of two membranes 57A, 57B.

[0037] The hull 9 also includes a skirt 59 ( figure 4 ) located under the loudspeakers 13A, 13B and partially masking the sole 29 of the frame 7.

[0038] The front part 3 of the acoustic enclosure is at least partially formed by the shell 9.

[0039] The hull 9 has a general “U” shape when viewed along a view axis E, orthogonal to the longitudinal axis L and to the transverse axis T.

[0040] The front portion 51 defines the aforementioned housing 15. The portion of the sphere formed by the front portion 51 is centered on a point located on the longitudinal axis L.

[0041] The cylinder portion formed by the intermediate part 53 is centered on the longitudinal axis L.

[0042] The rear walls 55A, 55B are for example parallel to the plane P. The rear walls define two rails 61A, 61B on the curvilinear edge 39 ( figures 5 And 6 ).

[0043] The rails 61A, 61B are respectively received in grooves 63A, 63B defined by the curvilinear edge 33 of the external part 25 of the frame.

[0044] The rails 61A, 61B and the corresponding grooves 63A, 63B are for example circular in view along the transverse axis T.

[0045] The openings 11A, 11B are advantageously circular and centered on the transverse axis T. The openings 11A, 11B are adapted to allow the introduction of the loudspeakers 13A, 13B into the internal volume 23 by translation along the transverse axis T.

[0046] The shell 9 comprises an inner layer 65 ( figures 5 And 6 ), delimiting the internal volume 23, and an external layer 67, or appearance layer, visible from the outside of the acoustic enclosure.

[0047] The inner layer 65 is thicker than the outer layer 67. The inner layer comprises, for example, polycarbonate (PC) reinforced with 15% to 25% by mass of glass fibers.

[0048] The outer layer 67 is for example made of acrylonitrile butadiene styrene (ABS).

[0049] The inserts 17A, 17B are advantageously structurally identical to each other. They are arranged symmetrically, as already stated, on either side of the plane P. Also, only the insert 17A will be described below with reference to the figure 7 .

[0050] The insert 17A is advantageously made of stainless steel. The insert is made from a metal sheet, for example having a thickness of between 0.6 mm and 1.5 mm.

[0051] The insert 17A comprises a circular part 69 located in an edge 71 of the shell 9 delimiting the opening 11A, and an adjacent part 73 located in the rear wall 55A.

[0052] The role of the circular part is to stiffen the edge of the shell 9 delimiting the opening 11A. Indeed, the loudspeakers 13A, 13B are rigidly fixed on the internal part 21 of the frame 7, and are devoid of any rigid connection with the shell 9 other than that formed by the frame. Also, the edge 71 is cantilevered relative to the loudspeaker 13. The same applies symmetrically relative to the plane P for the loudspeaker 13B and the edge of the shell delimiting the opening 11B.

[0053] The adjacent portion 73 stiffens the rear wall 55A. This notably prevents pumping phenomena, i.e. vibrations of the rear wall 55A due to pressure fluctuations in the internal volume 23 caused by the transverse movement of the membranes 57A, 57B of the loudspeakers 13A, 13B.

[0054] The assembly of the loudspeaker 1 will now be briefly described.

[0055] To assemble the acoustic enclosure, electronic elements (not shown) are first fixed to the frame 7 in the internal volume 23. The frame 7 and the shell 9 are then assembled by fitting together along the longitudinal axis L. The rails 61A, 61B are housed in the grooves 63A, 63B. The sealing gasket 37 is compressed between the curvilinear edge 33 and the external part 19 of the frame and the curvilinear edge 39 of the shell.

[0056] Nut 47 is screwed onto stud 45 to fix the shell to frame 7. The fixing requires a single screw / nut system.

[0057] The number and thickness of the washers 49 allows the distance between the frame and the shell to be adjusted along the longitudinal axis L.

[0058] The loudspeaker 13B is then introduced into the internal volume 23 through the opening 11B of the shell along the transverse axis T. The loudspeaker 13B is fixed to the internal part 21 using a screw (not shown) introduced into the orifice 41 and screwed from the opposite side of the internal part 21 relative to the loudspeaker 13B.

[0059] The loudspeaker 13A is then introduced into the internal volume 23 through the opening 11A along the transverse axis T. The loudspeaker 13A is then glued to the gluing surface 43 of the internal part 21.

[0060] Before being fixed, the loudspeakers 13A, 13B are electrically connected to the amplifier (not shown).

[0061] The third speaker (not shown) is fixed in housing 15.

[0062] Thanks to the features described above, the assembly of the loudspeaker is easy and the shell 9 has a smoother appearance.

Claims

1. An acoustic speaker (1) including: - a metal armature (7), - a plastic shell (9) fastened on the armature (7), the shell (9) defining at least two openings (11A, 11B), and - at least two loudspeakers (13A, 13B) arranged back-to-back along a transverse axis (T), the two loudspeakers (13A, 13B) respectively extending through the two openings (11A, 11B), characterized in that: - the shell (9) is in one piece, - the shell (9) and an outer part (19) of the armature (7) are suitable for nesting in one another along a longitudinal axis (L), the outer part (19) and the shell (9) at least partially defining an inner volume (23) of the acoustic speaker (1), - the armature (7) comprises an inner part (21) located between the two loudspeakers (13A, 13B) along the transverse axis (T), the shell (9) being fastened on the inner part (21), and - the two loudspeakers (13A, 13B) are rigidly fastened on the inner part (21) of the armature (7), and are preferably devoid of any rigid connection with the shell (9) other than that formed by the armature (7).

2. The acoustic speaker (1) according to claim 1, oblong along the longitudinal axis (L), a rear part (5) of the acoustic speaker (1) along the longitudinal axis (L) being formed by the outer part (19) of the armature (7), and a front part (3) of the acoustic speaker (1) along the longitudinal axis (L) being at least partially formed by the shell (9).

3. The acoustic speaker (1) according to claim 1 or 2, wherein the shell (9) is fastened on the inner part (21) by a screw-nut system (45, 47), preferably by a single screw-nut system (45, 47).

4. The acoustic speaker (1) according to any one of claims 1 to 3, wherein the shell (9) and the outer part (19) of the armature (7) respectively include two curved edges (33, 39), the two curved edges (33, 39) being adjacent to one another, the acoustic enclosure (1) including a sealing gasket (37) arranged between the two curved edges (33, 39) and forming a loop extending along the two curved edges (33, 39).

5. The acoustic speaker (1) according to any one of claims 1 to 4, wherein: - the shell (9) is generally U-shaped seen along an axis (E) orthogonal to the longitudinal axis (L) and the transverse axis (T); and - the outer part (19) of the armature (7) is generally U-shaped seen along the transverse axis (T).

6. The acoustic speaker (1) according to any one of claims 1 to 5, wherein the two openings (11A, 11B) are respectively delimited by two edges (71), preferably circular, the acoustic speaker (1) comprising at least two metal inserts (17A, 17B) respectively overmolded by said two edges (71).

7. The acoustic speaker (1) according to any one of claims 1 to 6, wherein: - each of the two loudspeakers (13A, 13B) comprises a membrane (57A, 57B) suitable for emitting sound waves, and - the shell (9) comprises, successively along the longitudinal axis (L), a front part (51) forming a sphere portion, an intermediate part (53) forming a cylinder portion, and two back walls (55A, 55B) located longitudinally behind the membranes (57A, 57B) of the two loudspeakers (13A, 13B).

8. The acoustic speaker (1) according to claim 7, further comprising two metal inserts (17A, 17B) respectively overmolded by the back walls (55A, 55B) of the shell (9).

9. The acoustic speaker (1) according to any one of claims 1 to 8, wherein the shell (9) comprises: - an inner layer (65) including polycarbonate (PC), and between 15% and 25% by weight of glass fibers, and - an outer layer (67) including acrylonitrile butadiene styrene (ABS).