SOUND-ATTENUATING ENCLOSURE WITH INTEGRAL COOLING DUCTS

RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Patent Application No.

60/638,531, filed on December 23, 2004, titled "Sound Attenuating Enclosure with Integral

Cooling Ducts", the entire content of which is incorporated herein by reference.

FIELD OF THE INVENTION

[0002] The invention relates to machine enclosures. More particularly, the invention relates

to a sound-attenuating enclosure including cooling air ducts.

BACKGROUND

[0003] Machinery, such as portable compressors and generators, often produce relatively

high levels of noise during operation. Enclosures have been fitted around such machinery to

reduce the emitted noise. However, the enclosures generally restrict the flow of cooling air,

which is necessary to avoid overheating. Openings have been- added to the enclosures allowing

cooling air to enter the enclosure, but the openings also permit noise to escape.

[0004] Internal baffles have been used to reduce the amount of noise escaping through the

openings, but these baffles increase the cost of the enclosure. Additionally, enclosures with

extensive baffles at the inlets usually cause a reduction in airflow or a redirection of cooling air

away from critical areas that must remain cool.

SUMMARY

[0005] In one embodiment, the invention provides a sound-attenuating enclosure for enclosing a portable machine. The sound-attenuating enclosure includes an inner shell having an

inner air inlet opening, an outer shell having an outer air inlet opening, and a duct passage

between the inner shell and the outer shell connecting the inner air inlet opening and the outer air

inlet opening. The inner shell is positioned within the outer shell to form a space between the

inner shell and the outer shell. The outer air inlet opening is offset from the inner air inlet

opening to prevent a line-of-sight between the outer air inlet opening and the inner air inlet

opening.

[0006] In another embodiment, the invention provides a portable machine assembly

including a towing structure having at least one towing bar and at least one wheel, a base

coupled to the towing structure, an inner shell having an inner air inlet opening, and an outer

shell having an outer air inlet opening offset from the inner air inlet opening to prevent a line-of-

sight between the outer air inlet opening and the inner air inlet opening. The inner shell is

positioned inside the outer shell to form a space between the outer shell and the inner shell to

define a duct between the inner air inlet opening and the outer air inlet opening.

[0007] Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Fig. 1 is perspective view of a sound-attenuating enclosure coupled to a towing base.

[0009] Fig. 2 is an exploded side elevation view of inner and outer shells of the enclosure of

Fig. 1.

[0010] Fig. 3 is a side elevation view of the enclosure of Fig. 1.

[0011] Fig. 4 is a cross-sectional view of the enclosure taken along line 4-4 of Fig. 3.

DETAILED DESCRIPTION

[0012] Before any embodiments of the invention are explained in detail, it is to be

understood that the invention is not limited in its application to the details of construction and

the arrangement of components set forth in the following description or illustrated in the

following drawings. The invention is capable of other embodiments and of being practiced or of

being carried out in various ways. Also, it is to be understood that the phraseology and

terminology used herein is for the purpose of description and should not be regarded as limiting.

The use of "including," "comprising," or "having" and variations thereof herein is meant to

encompass the items listed thereafter and equivalents thereof as well as additional items. Unless

specified or limited otherwise, the terms "mounted," "connected," "supported," and "coupled"

and variations thereof are used broadly and encompass both direct and indirect mountings,

connections, supports, and couplings. Further, "connected" and "coupled" are not restricted to physical or mechanical connections or couplings.

[0013] Fig. 1 illustrates a portable machine 10 including a sound-attenuating enclosure 12

having cooling ducts 14 and the enclosure 12 being releasably coupled to a base 16. In one

embodiment, the base 16 has a substantially rectangular shape and can support various types of

machinery or objects, such as internal combustion engines, air compressors, tool boxes, etc. The

base 16 is mounted on a support structure 17 having a towable frame 18 and a set of wheels 20

releasably coupled to an axle (not shown). Other embodiments of the invention can include the

sound-attenuating enclosure 12 and the base 16 supported by other support structures.

[0014] As shown in Fig. 2, the sound-attenuating enclosure 12 includes an outer shell 40 and

an inner shell 50. Figs. 1-2 illustrate that the outer shell 40 includes an upper wall 22, a front

wall 24, a rear wall 26, and two side walls 28. In one embodiment, the upper wall 22 includes

air exhaust openings 30 evenly spaced between the first and second side walls 28 and

substantially adjacent to the front wall 24. One or more side walls 28 of the outer shell 40

include an instrument panel opening 32 having a substantially square shape, in one embodiment.

The instrument panel opening can provide access to a control panel 34. In other embodiments,

the instrument panel opening 32 can have different shapes or provide access to other portions of

a portable machine supported by the base 16. In one embodiment, the side walls 28 also include

air intake openings 36 substantially evenly spaced in the direction from the rear wall 26 to the

front wall 24 of the outer shell 40. The air intake openings 36 extend in the direction from the base 16 to the upper wall 22 until reaching the lower edge of a duct wall 38.

[0015] The duct wall 38 projects outwardly from the surface of the outer shell 40 and is

defined by the edges of the front, rear, and side walls 24, 26, 28. As shown in Figs. 1-3, the duct

wall 38 is closer to the upper wall 22 than the base 16 at the rear wall 26. From the rear wall 26,

the duct wall 38 slopes toward the base 16 as the duct wall 38 approaches the front wall 24 of the

outer shell 40. In other embodiments, the duct wall 38 can have other configurations, such as

being spaced a uniform distance from the upper wall 22 along the duct wall's entire length or

perimeter. The walls of the outer shell 40 form an enclosed space 52 to receive the inner shell

50.

[0016] As shown in Fig. 2, the inner shell 50 includes an upper wall 54, a front wall 56, a rear wall 58, and two side walls 60 to form an interior space 62. The upper wall 54 includes

inner shell air exhaust outlets (not shown) at least partially forming the air exhaust openings 30

shown in Fig. 1. The upper wall 54 also includes upper wall projections 66 having rib-like

structures. The upper wall projections 66 generally extend linearly between the front and rear

walls 56, 58. One or more of the side walls 60 includes an inner shell instrument panel opening

68 partially of fully aligned with the outer shell instrument panel opening 32 to provide access to

a control panel 34 of a compressor system or other machine supported by the base 16. As shown

in Fig. 1, a sealing wall 76 extends from the edges of the inner shell instrument panel opening 68

to the outer shell instrument panel opening 32 of the sound-attenuating enclosure 12. The side

walls 60 include ribs 70 projecting outwardly from the side walls 60 of the inner shell 50. The

ribs 70 extend substantially vertically from the bottom of the inner shell 50 to various levels of

the side walls 60 generally coinciding with the upper edge of the duct wall 38 when the inner

shell 50 is positioned inside of the outer shell 40, as shown in Fig. 3.

[0017] In one embodiment, the ribs 70 projecting from the side walls 60 are substantially

evenly spaced. As shown in Figs. 2-3, the side walls 60 include inner shell air inlet openings 74

extending between the ribs 70 and being vertically aligned with the air intake openings 36. Wall

sections 78 extend between the ribs 70 to at least partially form the cooling ducts 14. The air

intake openings 36, the wall sections 78, the duct wall 38, and the inner shell air inlet openings

74 cooperate to form the cooling ducts 14 to allow cooling air into an interior space 62. As a

result, the cooling ducts 14 do not include a line-of-sight between the interior space 62 and the

air intake openings 36.

[0018] Fig. 3 illustrates the inner shell 50 (shown in dashed lines) coupled to the outer shell

40 (shown in solid lines) to define the sound-attenuating enclosure 12. The upper wall

projections 66, the wall supports 72, and the ribs 70 defined by the inner shell 50 are raised to

support the outer shell 40 at a distance from the inner shell 50. The space between the outer

shell 40 and the inner shell 50 can help prevent vibration. In addition, the space between the

outer shell 40 and the inner shell 50 helps dampen noise from the motor or compressor system.

Moreover, the sealing wall 76 (as shown in Fig. 1) also helps to seal the space between the outer

shell 40 and the inner shell 50 reducing the noise from the motor or compression system that

escapes the enclosure 12.

[0019] As shown in Figs. 3-4, the ribs 70, the wall sections 78, and the duct wall 38

generally define the cooling ducts 14 extending from the air intake openings 36 to the inner shell

air inlet openings 74. The cooling ducts 14 allow cooling air to flow into the interior space 62

and to minimize the sound exiting the sound-attenuating enclosure 12. In general, the sound-

attenuating enclosure 12 is configured to allow cooling air to flow into the interior space 62

through the cooling ducts 14 and out of the interior space 62 through the air exhaust openings

30. However, cooling air can potentially flow into the interior space 62 through the air exhaust

openings 30 and out of the interior space 62 through the cooling ducts 14.

[0020] In some embodiments, the outer shell 40 and the inner shell 50 are each formed as a

molded part. However, the outer shell 40 and the inner shell 50 can also be manufactured with

multiple components joined together. In some embodiments, sound absorbing material can be

positioned in the space between the outer shell 40 and the inner shell 50. In some embodiments,

the outer shell 40 can be manufactured with integral air pockets 80 (as shown in Fig. 4) to reduce the sound from by the motor or compressor system that exits the enclosure 12.

[0021] Various features and advantages of the invention are set forth in the following claims.