Abstract:
An air compressor having improved stability and portability. The air compressor package is positionable in an operational position, wherein the air compressor package is positioned on a base, and a transport position, wherein the air compressor package may be more readily transported. Positioning of the air compressor package into the transport position is accomplished by rotating the air compressor about a rotational axis that is generally parallel to the longitudinal axis of the air tank, which positions the air compressor in an orientation and position that is relatively comfortable, whether or not the air compressor is hand-transported. The air compressor package can employ a compact manifold that can couple the air tank to the compressor and a regulator valve and optionally to a relief valve, a drain valve and/or a pressure switch. A method for operating a compressor is also provided.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is a continuation-in-part of U.S. patent application Ser. No. 10/805,987, filed Mar. 22, 2004, and Ser. No. 11/053,033, filed Feb. 8, 2005, which are continuation-in-part applications of U.S. patent application Ser. No. 10/630,090 filed Jul. 30, 2003, which is a continuation of U.S. patent application Ser. No. 10/154,416 filed May 23, 2002. U.S. patent application Ser. No. 10/154,416 claimed the benefit of U.S. Provisional Application No. 60/366,676, filed Mar. 22, 2002 and is a continuation-in-part of U.S. application Ser. No. 29/136,877 filed Feb. 8, 2001. U.S. application Ser. No. 29/136,877 issued as U.S. Design Pat. No. D461,196 on Aug. 6, 2002. Each of the aforementioned applications is incorporated by reference. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention generally relates generally to the field of portable air compressors and more particularly to hand portable air compressors.  
       BACKGROUND OF THE INVENTION  
       [0003]     Small air compressors have become common tools around the home, workshop and work site. For home, recreation and other light duty uses such as inflating sports or recreation equipment or for emergency use in inflating a car tire a number of very small and lightweight compressors are available. Such tasks require relatively low-pressure compressed air and/or relatively low airflow rates. Weight is kept low and portability is maximized in these designs by use of small, low volume and/or low-pressure compressors powered by small lightweight electric motors. Additionally, significant weight, size and cost savings are achieved by the omission of a high-pressure vessel (i.e., air tank), as well as an oil lubrication system.  
         [0004]     Many jobs, however, require higher air pressures, and/or greater instantaneous air flow demands which typically exceed the capacity of the hobby or recreational use compressors. To satisfy the demands of higher air pressure and higher airflow tasks it is necessary to increase the size of the compressor and the related motor or engine. Furthermore, rather than sizing the compressor to meet the maximum theoretical instantaneous air flow demand, it is common design practice to include a compressed air reservoir in the form of an air tank or other pressure vessel. The tank, usually with an output regulator, can hold a quantity of pressurized air to meet peak demands from serviced loads, while allowing the use of a smaller and lighter compressor that charges the tank and is capable of meeting the average compressed air flow rate for the intended use.  
         [0005]     The air tank and the larger compressor that are typically required to meet the desired pressure and airflow levels substantially increase the weight and overall size of the compressor package. Units designed for high pressure and high volume tasks can rapidly reach a weight and size where the well-known motor vehicle mounted or towed trailer configuration is the only practical form. Still, there are a range of intermediate capacity air compressors that are common tools around the construction site and which are man portable.  
         [0006]     Current models of man portable air compressor packages comprise a stand or supporting structure on or in which are mounted a motor or engine, an air compressor, an air tank, a discharge manifold and various valves, instrumentation and controls. Many of the larger portable configurations are provided with wheels, in what is often referred to as a wheelbarrow configuration, so that they can be moved by a single user. Examples of wheeled air compressors include Models D55170 and D55270, which are marketed by The Black &amp; Decker Corporation under the DeWalt® trade name.  
         [0007]     Still, some users of intermediate capacity professional grade compressors find it necessary or desirable to have a compressor that is capable of being lifted and carried by hand. One common approach taken by air compressor manufacturers to improve the portability of such intermediate capacity professional grade compressors has been to redesign the air compressor so as to reduce its weight. Despite such efforts, intermediate capacity professional grade compressors frequently weigh more than 50 pounds and thus remain difficult to lift and move by hand, even for those users who are physically strong.  
         [0008]     Aside from the issue of their weight, hand-portable intermediate capacity professional grade compressors are also known to be quite cumbersome to transport. In this regard, the configurations that use two cylindrical tanks or a single pancake tank (i.e., a cylindrical tank of large diameter but small height with convex ends) have become common, as have the mounting schemes for mounting the compressor and the motor. For example, configurations that use two cylindrical tanks typically mount the compressor and motor alongside the tanks, whereas configurations that use a single pancake tank typically mount the compressor and motor on an end of the tank.  
         [0009]     These conventional air compressor arrangements provide a package with a relatively large base or footprint, and a center of gravity that is positioned in an approximately centered position within the footprint. While such arrangements provide the air compressor with a configuration that is relatively stable during its operation, lifting and carrying air compressors with these configurations tends to be rather awkward and difficult. In this regard, these configurations typically employ a handle (for lifting and carrying the air compressor) that is attached to an appropriate structure, such as the stand or the air tank, at a location that is located vertically above the center of gravity of the entire air compressor package. The handle is generally oriented in a manner that requires the air compressor package to be lifted vertically upwards and carried in an orientation that is substantially the same as the orientation in which it is operated.  
         [0010]     Lifting and carrying the known intermediate air compressor packages in this manner, however, is relatively difficult, since the footprint of these air compressor packages tends to be relatively large and thus requires the user to hold the air compressor package with a somewhat outstretched arm such that the wrist of the user is in a state of flexion. In an effort to bring the air compressor package&#39;s center of gravity closer to the central axis of the user, the user will typically tilt their upper body away from the load of the air compressor package and thus will lift and transport the air compressor package with a body posture that is uncomfortable and awkward.  
       SUMMARY OF THE INVENTION  
       [0011]     In one form, the present teachings provide an air compressor that includes a support structure, a compressor and an air tank in fluid connection with the compressor. The air tank has a capacity of at least 0.5 gallons. The support structure includes a tubular frame that defines a pair side members and a handle that is disposed between and connects the side members. Each side member includes a first leg, an arm and a second leg. The first leg is disposed under a first side of the compressor and secured to the air tank at a first location. The second leg has a first portion, which is generally parallel to the first leg, and a second portion that extends downwardly toward the first leg and outwardly toward the handle. The air tank has a generally cylindrical shape and extends longitudinally between the side members. The air tank abuts the first legs and the second portion of the second legs. The handle is configured to be grasped by a hand of a user so that the air compressor can be rotated about an axis that is generally parallel to a longitudinal axis of the air tank between an operating position and a hand-carried transport position.  
         [0012]     In another form, the present teachings provide a method that includes: providing an air compressor apparatus having a support structure, a compressor, an air tank and a handle, the air tank being in fluid connection with the compressor and having a capacity that is greater than about 0.5 gallons, the handle being coupled to at least one of the support structure and the air tank; the support structure defining a base; placing the air compressor apparatus in an operating position wherein the base is disposed in a first orientation; and moving the air compressor apparatus to a hand-carried transport position by rotating the air compressor apparatus by the handle about an axis that is generally parallel to the handle, the base being disposed in a second orientation that is generally perpendicular to the first orientation when the air compressor apparatus is in the hand-carried transport position.  
         [0013]     In still another form, the present teachings provide an air compressor with a compressor, an air tank having a tank wall that defines a tank cavity, a regulator valve and a manifold. The manifold has a manifold body that includes an inlet port and an outlet port. The manifold body is threadably coupled to the air tank. The inlet port is coupled in fluid connection to tank cavity and the compressor, while the outlet port is separate from the inlet port and in fluid connection with the tank cavity and the pressure regulator.  
         [0014]     Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]     Additional advantages and features of the present invention will become apparent from the subsequent description and the appended claims, taken in conjunction with the accompanying drawings, wherein:  
         [0016]      FIG. 1  is a perspective view of a compressor package constructed in accordance with the teachings of the prior art;  
         [0017]      FIG. 2  is a front view of a user transporting the compressor package of  FIG. 1 ;  
         [0018]      FIG. 3  is a perspective view of an air compressor package constructed in accordance with the teachings of the present invention;  
         [0019]      FIG. 4  is a left side elevational view of the air compressor package of  FIG. 3  as positioned in an operational position;  
         [0020]      FIG. 5  is a rear elevational view of the air compressor package of  FIG. 3 ;  
         [0021]      FIG. 6  is a bottom plan view of the air compressor package of  FIG. 3 ;  
         [0022]      FIG. 7A  is a left side elevational view of the air compressor package of  FIG. 3  as it is being rotated into a transport position;  
         [0023]      FIG. 7B  is a left side elevational view of the air compressor package of  FIG. 3  as positioned in the transport position;  
         [0024]      FIG. 8  is a perspective view of an air compressor package constructed in accordance with the teachings of an alternate embodiment of the present invention;  
         [0025]      FIG. 9  is a left side elevational view of the air compressor package of  FIG. 8  as positioned in a transport position;  
         [0026]      FIG. 10  is a perspective view of an air compressor package constructed in accordance with the teachings of another alternate embodiment of the present invention;  
         [0027]      FIG. 11  is a left side elevational view of an air compressor package constructed in accordance with the teachings of still another alternate embodiment of the present invention;  
         [0028]      FIG. 12  is a front perspective view of another air compressor package constructed in accordance with the teachings of the present invention;  
         [0029]      FIG. 13  is a rear perspective view of the air compressor package of  FIG. 12 ;  
         [0030]      FIG. 14  is a left side elevation view of the air compressor package of  FIG. 12 ;  
         [0031]      FIG. 15  is a perspective view of an air compressor package constructed in accordance with the teachings of another alternate embodiment of the present invention;  
         [0032]      FIG. 16  is a left side elevational view of the air compressor package of  FIG. 15  as positioned in an operational position;  
         [0033]      FIG. 17  is a top plan view of the air compressor package of  FIG. 15 ;  
         [0034]      FIG. 18  is a bottom plan view of the air compressor package of  FIG. 15 ;  
         [0035]      FIG. 19  is rear elevational view of the air compressor package of  FIG. 15 ;  
         [0036]      FIG. 20  is an exploded perspective view of a portion of the air compressor package of  FIG. 15 ;  
         [0037]      FIG. 21 a  left side elevational view of the air compressor package of  FIG. 15  as it is being rotated into a transport position;  
         [0038]      FIG. 22  is a left side elevational view of the air compressor package of  FIG. 15  as positioned in the transport position;  
         [0039]      FIG. 23  is a perspective view of another air compressor package constructed in accordance with the teachings of the present disclosure;  
         [0040]      FIG. 24  is a side perspective view of the air compressor package of  FIG. 22 ;  
         [0041]      FIG. 25  is a perspective view of a portion of the air compressor package of  FIG. 23  with the cowling removed;  
         [0042]      FIG. 26  is an enlarged perspective view of a portion of the air compressor package of  FIG. 23  illustrating the coupling of the manifold to the air tank in greater detail;  
         [0043]      FIG. 27  is a perspective view of the manifold;  
         [0044]      FIG. 28  is a longitudinal section view of the manifold taken through the inlet and outlet ports;  
         [0045]      FIG. 29  is a section view perpendicular to the longitudinal axis of the manifold through the outlet port, the pressure port and the relief port;  
         [0046]      FIG. 30  is a longitudinal section view of the manifold taken through the drain port;  
         [0047]      FIG. 31  is a section view similar to  FIG. 30  but taken through the air tank and the manifold; and  
         [0048]      FIG. 32  is an enlarged view of a portion of  FIG. 32 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0049]     With reference to  FIGS. 1 and 2  of the drawings, a prior art air compressor package  1  is illustrated to include a support structure  2 , a compressor mechanism  3 , an air tank  4  and a handle  5 . The compressor mechanism  3  and the air tank  4 , which are among the heavier components of the air compressor package  1 , are distributed horizontally about the support structure  2  such that the center of gravity  6  of the air compressor package  1  is disposed well within the interior of an area bounded by the support structure  2 . The handle  5  is coupled to the support structure  2  in a manner that places a centerline  7  of the handle  5  vertically in-line with the center of gravity  6  of the air compressor package  1 .  
         [0050]     With additional reference to  FIG. 2 , the configuration of the handle  5  is such that it permits the air compressor package  1  to be lifted vertically and transported in the same orientation as it is operated. The size of the footprint or base  8  of the air compressor package  1 , however, is relatively large, which necessitates that the user  9  transport the air compressor package  1  with a somewhat outstretched arm  9   a . Consequently, the user&#39;s wrist  9   b  is maintained in a state of flexion, which tends to be uncomfortable for the user and fatiguing.  
         [0051]     In  FIGS. 3 through 5 , an air compressor package constructed in accordance with the teachings of the present invention is generally indicated by reference numeral  10 . The air compressor package  10  is illustrated to include a compressor mechanism  12 , an air tank  14 , a support structure  16 , a handle  18  and a gauge package  20 . The compressor mechanism  12  is conventional in its construction and operation and as such, need not be discussed in detail herein. Briefly, the compressor mechanism  12  includes a compressor  22 , which is operable for intaking and compressing ambient air, and a power source, such as an electric motor  24  or an engine, for providing power to the compressor  22 . The compressed air that exits the compressor  22  is discharged to the air tank  14 , which serves as a reservoir for the compressed air.  
         [0052]     The air tank  14  has a capacity of at least 0.5 gallons and in the particular example provided, is illustrated as having a single cylindrically shaped tank structure. The air tank  14 , however, preferably has a capacity of about 1 to about 8 gallons, and more preferably a capacity of about 3 to about 5 gallons. Those skilled in the art will understand that the air tank  14  may be configured somewhat differently, as with a conventional pancake-style (i.e., a relatively short and large diameter cylinder with convex ends) tank structure (not shown) or with a plurality of tank structures that are coupled in fluid connection.  
         [0053]     The support structure  16  is illustrated to be configured in a “roll-cage” manner that extends around both the compressor mechanism  12  and the gauge package  20  to protect these components should the air compressor package  10  be overturned or impacted by another object. In the particular embodiment illustrated, the support structure  16  includes a tubular frame  30  having opposite laterally extending sides  32  that are interconnected by a mounting platform  34  and a plurality of strut members  36 , as well as an optional shield or cover  38 . In the example provided, the cover  38  is formed from a sheet material, such as steel, aluminum or plastic, and is removably fastened with, for example, conventional threaded fasteners (not shown) to the tubular frame  30 . While the primary purpose of the cover  38  is to protect components such as the compressor mechanism  12  and the gauge package  20  from damaging contact with, for example, falling tools and workpieces, those skilled in the art will understand that the relatively smooth outer surface of the cover  38 , when abutted against the lateral side of the user during transport, is relatively more comfortable and less likely to interfere with the movement of the user as compared to the tubular frame  30 , the compressor mechanism, the air tank  14  and/or the gauge package  20 .  
         [0054]     In the example provided, the laterally extending sides  32  are constructed in an open manner, such that the ends  42  of the laterally extending sides  32  do not intersect one another but rather intersect the air tank  14 . The ends  42  are coupled to the air tank  14  through a conventional coupling means, such as welds. In the particular embodiment illustrated, the air tank  14  extends through the laterally extending sides  32  but those skilled in the art will understand that the air tank  14  could alternatively be configured to terminate flush or inboard of the laterally extending sides  32  so that the support structure  16  would also protect the opposite ends of the air tank  14 . The gauge package  20 , which conventionally includes an air tank pressure gauge  46 , a regulator  48 , a regulator gauge  50  and an outlet manifold  52 , is coupled to a gauge panel  54  that is mounted between the laterally extending sides  32  of the support structure  16 . The gauge panel  54  may be a discrete component or may be integrally formed with the cover  38 . Preferably, the gauge panel  54  is mounted in a rearwardly sloped orientation, which is best illustrated in  FIGS. 3 and 4 , as opposed to the substantially vertical orientation that is illustrated in the prior art air compressor package  1  of  FIG. 1 , so as to position the air tank pressure gauge  46 , the regulator  48 , the regulator gauge  50  and the outlet manifold  52  in a manner that is relatively more comfortable for the user of the air compressor package  10  to read and/or access. As those skilled in the art will appreciate from this disclosure, the improved readability of the air tank pressure gauge  46  and the regulator gauge  50  and the improved accessibility of the regulator  48  that result from the positioning of the gauge panel  54  in a rearwardly sloped orientation improves the accuracy with which the user is able to control the air pressure that is delivered to the outlet manifold  52 . Pegs  58 , which are coupled to one of the laterally extending sides  32  and extend outwardly therefrom, are optionally provided so as to permit items, such as a power cord  60  or an air hose  62 , to be coiled (around the pegs  58 ) for storage.  
         [0055]     The mounting platform  34 , which is illustrated to be fabricated from a sheet material, such as steel, aluminum or plastic, serves as the base  66  of the support structure  16 . The compressor mechanism  12  is coupled to the mounting platform  34  via a plurality of threaded fasteners (not specifically shown). A plurality of rubber feet  68  are affixed to the corners of the mounting platform  34  and serve to dampen vibrations that are transmitted through the support structure  16  as well as to provide the support structure  16  with a degree of skid resistance. With specific reference to  FIG. 6 , an access aperture  70  is formed through the mounting platform  34  and permits the user to access a valve mechanism  72  to manually drain the air tank  14 .  
         [0056]     With renewed reference to  FIG. 4 , those skilled in the art will appreciate that the air tank  14  and the compressor mechanism  12  are coupled to the support structure  16  such that their centers of gravity, CG AT  and CG AC , respectively, are positioned relatively close to the base  66  when the air compressor package  10  is oriented in its operational position ( FIGS. 3 through 5 ). As the air tank  14  and the compressor mechanism  12  account for a majority of the weight of the air compressor package  10 , configuration in this manner is advantageous in that it provides the air compressor package  10  with a relatively low center of gravity CG ACP . As those skilled in the art will understand, the center of gravity CG ACP  acts along a plane  80  that is skewed to the base  66 . In the particular embodiment illustrated, the plane  80  is substantially perpendicular to the base  66  since the base  66  is situated on a flat surface  82 , such as a floor.  
         [0057]     With reference to  FIGS. 3 and 7 , the handle  18  is configured to be gripped by a palmar surface  90  of the hand  92  of a user  94  when the user  94  is transporting the air compressor package  10 . The handle  18  may be of any type and may be mounted to any appropriate structure, such as the support structure  16  or the air tank  14 . In the particular embodiment illustrated, the handle  18  is fixedly mounted to air tank  14  and includes a grip portion  96  that is contoured to receive the fingers of the user when the user is transporting the air compressor package  10 . The grip portion  96  is formed about a centerline  98  that lies in (or is positionable into) a plane  100  that includes the center of gravity CG ACP  of the air compressor package  10 .  
         [0058]     The handle  18  permits the user of the air compressor package  10  to reposition the air compressor package  10  from the operational position that is illustrated in  FIG. 4  to a transport position that is illustrated in  FIG. 7A . To facilitate repositioning of the air compressor package  10  in this manner, a protective stop  69  may be fastened with, for example, conventional threaded fasteners (not shown) to each of the laterally extending sides  32  of the tubular frame  30 . The protective stops  69  are preferably comprised of rubber or some other type of material having an adhesive characteristic. In some instances, the user may roll air compressor package onto its side as shown in  FIG. 7B . In these instances, the protective stops  69  prevent any unwanted slippage of the air compressor package away from the user. When positioned in the transport position, the plane  100  that includes the centerline  98  of the handle  18  and the center of gravity CG ACP  of the air compressor package  10  is located in a substantially vertical orientation that is generally parallel to a vertical (longitudinal) axis  104  of the user  94 , as well as generally parallel to the base  66  and the top  108  of the air compressor package  10 .  
         [0059]     Furthermore, since the center of gravity CG ACP  of the air compressor package  10  is relatively close to the base  66  when the air compressor package  10  is oriented in the operational position, the user  94  is able to transport the air compressor package  10  such that the base  66  is proximate a lateral side  110  of the user  94  (i.e., within about 10 inches of the lateral side  110 , and preferably about 3 inches to about 7 inches) and the user&#39;s wrist  112  is not in a state of flexion. When placed in the transport position, the air compressor package  10  is preferably configured such that the centers of gravity CG AT  and CG AC  of the air tank  14  and the compressor mechanism  12  are disposed in the plane  100 , or oppositely offset therefrom by substantially equal distances. With the handle  18  thus positioned, the user  94  is able to comfortably carry the air compressor package  10 , as well as to easily pivot the air compressor package  10  between the operational position and the transport position without releasing the handle  18 .  
         [0060]     While the air compressor package  10  has been described thus far as including an air tank  14  with a single cylindrically shaped tank structure and a handle  18  that is fixedly coupled to the air tank  14 , those skilled in the art will appreciate that the invention, in its broader aspects, may be constructed somewhat differently. For example, the handle  18   a  may be incorporated into the support structure  16   a  as illustrated in  FIGS. 8 and 9 . In this embodiment, the support structure  16  extends around the air tank  14  on a side opposite the compressor mechanism  12  and upwardly from the base  66 . A grip structure  96   a  is formed on the front strut member  36   a  that interconnects the opposite laterally extending sides  32   a . Like the handle  18  of the air compressor package  10  that is illustrated in  FIG. 3 , the handle  18   a  is positioned such that a centerline  98   a  of the grip structure  96   a  is positioned in a plane that contains the center of gravity CG ACP  of the air compressor package  10   a  when the air compressor package  10   a  is positioned in the transport position.  
         [0061]     In the arrangement of  FIG. 10 , the handle  18   a  is similar to that of the embodiment of  FIG. 8  in that it is incorporated with the support structure  16   a . The air tank  14   b , however, includes first and second generally cylindrical tank structures  150   a  and  150   b  which are stacked vertically relative to one another when the air compressor package  10   b  is placed in the operating position. In the arrangement illustrated, the first and second generally cylindrical tank structures  150   a  and  150   b  are disposed equidistantly on opposite sides of the plane (not specifically shown) that includes the centerline  98   a  of the handle  18   a  and the center of gravity CG ACP . The longitudinal axes  152   a  and  152   b  of first and second generally cylindrical tank structures  150   a  and  150   b , respectively, are illustrated to contained in a plane that is skewed to the base  66  to thereby minimize the amount by which the first and second generally cylindrical tank structures  150   a  and  150   b  are offset from the plane that includes the centerline  98   a  of the handle  18   a  and the center of gravity CG ACP . In this arrangement, the mounting platform  34   b  may be elevated slightly relative to the mounting platform  34  of the air compressor package  10  so as to more easily and compactly package the air tank  14   b  and the compressor mechanism  12  so that the centerline  98   a  of the handle  18   a  is positioned in the manner described above.  
         [0062]     The arrangement of  FIG. 11  is generally similar to that of  FIG. 3 , except that the handle  18   c  is pivotably coupled to the support structure  16   c  on a side opposite the air tank  14 . When positioned into the transport position, the compressor mechanism  12  is situated above the air tank  14 . This arrangement also illustrates that the air compressor package of the present invention may be rotated about a generally horizontal axis between the operational and transport positions in any direction. For example, the embodiment of  FIGS. 6 and 7  illustrate that the air compressor package  10  may be rotated from the front F of the air compressor package  10  to the bottom B (or top T) of the air compressor package  10 , whereas the embodiment of  FIG. 11  illustrates that the air compressor package  10   c  may be rotated from the rear R of the air compressor package  10   c  to the bottom B (or top T) of the air compressor package  10   c . Those skilled in the art will understand that the air compressor package may alternatively be configured to rotated from a side of the air compressor package to the bottom (or top) of the air compressor package via handle  18   c.    
         [0063]     With reference to  FIGS. 12 and 13 , another air compressor package constructed in accordance with the teachings of the present invention is generally indicated by reference numeral  10   d . The air compressor package  10   d  is somewhat similar to the air compressor package  10  illustrated in  FIG. 3  and may include a compressor mechanism  12 , an air tank  14 , a support structure  16 , a handle  18  and a gauge package  20 . The compressor mechanism  12  may include an oil-less or oil-free compressor  22   d  and a power source, such as an electric motor  24  or an engine, for providing power to the oil-less compressor  22   d . The oil-less compressor  22   d  includes a piston  300  that reciprocates along an axis  302  to intake and compress ambient air. The term oil-less is used herein to describe an air compressor that that does not use sump for holding a liquid oil for lubrication of the piston  300  as it reciprocates. Preferably, the entire compressor  22   d , including the crankcase (not shown), may be operated without a liquid lubricating oil. The compressed air that exits the compressor  22   d  is discharged to the air tank  14 , which serves as a reservoir for the compressed air.  
         [0064]     The air tank  14  may have a capacity of at least 0.5 gallons and in the particular example provided, is illustrated as having a single cylindrically shaped tank structure. The air tank  14 , however, may have a capacity of about 1 to about 8 gallons, and more preferably a capacity of about 3 to about 5 gallons.  
         [0065]     The support structure  16  may include a pair of tubular supports  30   d  and a mounting platform  34   d . The mounting platform  34   d  may include a base member  310  and a pair of side members  312  that may be coupled to and extend outwardly from the base member  310 . With additional reference to  FIG. 14 , each side member  312  may include an arcuate end surface  314  that is configured to abut a portion of the perimeter of the air tank  14  when the base member  310  is abutted against the air tank  14 . While the base member  310  may be abutted against the air tank  14  at any location in the lower quadrant  320  of the air tank, an upper surface  322  of the base member  310  may be positioned such that it is generally parallel to a first plane  324  that extends longitudinally through and bisects the air tank  14  and an edge  326  of the base member  310  terminates at a point that is included in a second plane  328  that is generally perpendicular to the first plane  324  and which extends longitudinally through and bisects the air tank  14 . Configuration in this manner positions a center of gravity of the air tank  14  (i.e., CG AT ) relatively close to the base member  310  and prevents the air tank  14  from extending below the mounting platform  34   d . Those of ordinary skill in the art will appreciate that exact alignment of the edge  326  to the plane  328  cannot be reliably accomplished on a mass-production basis and as such, it will be understood for the purposes of this disclosure and the appended claims that the edge  326  is positioned in the plane  328  when a deviation between the edge  326  and the plane  328  is less than or equal to 0.25 inch (i.e., 0.25 inch on either side of the plane  328 ).  
         [0066]     A first end of the tubular supports  30   d  may be coupled to the base member  310  and a second, opposite end of the tubular supports  30   d  may be coupled to the air tank  14 . The tubular supports  30   d  are positioned on opposite sides of the compressor mechanism  12  to thereby protect the compressor mechanism  12  should the air compressor package  10   d  be overturned or impacted by another object.  
         [0067]     In the example provided, a shroud  330 , which may be formed from a sheet metal or plastic material, may be removably coupled to the support structure  16  and/or the compressor mechanism  12 . While the primary purpose of the shroud  330  is to protect components such as the compressor mechanism  12  and the gauge package  20  from damaging contact with, for example, falling tools and workpieces, those skilled in the art will understand that the relatively smooth outer surface of the shroud  330 , if abutted against the lateral side of the user during transport, is relatively more comfortable and less likely to interfere with the movement of the user as compared to other portions of the air compressor package  10   d.    
         [0068]     The gauge package  20  may conventionally include an air tank pressure gauge (not shown), a regulator (not shown), a regulator gauge (not shown) and an outlet manifold  52 , and may be mounted to any convenient point, such as to the air tank  14 , the support structure  16  or the compressor  22   d.    
         [0069]     The compressor mechanism  12  may be coupled to the mounting platform  34   d  via a plurality of threaded fasteners (not specifically shown). A plurality of rubber feet  68  may be affixed to the corners of the mounting platform  34   d  to dampen vibrations that are transmitted through the support structure  16  as well as to provide the support structure  16  with a degree of skid resistance. An access aperture (not specifically shown), similar to the access aperture  70  in  FIG. 6 , may be formed through the mounting platform  34   d  to permit the user to access a valve mechanism  72  to manually drain the air tank  14 .  
         [0070]     With specific reference to  FIG. 14 , the air tank  14  and the compressor mechanism  12  may be coupled to the support structure  16  such that their centers of gravity, CG AT  and CG AC , respectively, are positioned relatively close to the base member  310 . As the air tank  14  and the compressor mechanism  12  account for a majority of the weight of the air compressor package  10   d , configuration in this manner is advantageous in that it provides the air compressor package  10   d  with a center of gravity CG ACP  that is located relatively close to a surface onto which the air compressor package  10   d  has been placed, thereby rendering the air compressor package  10   d  relatively resistant to tipping.  
         [0071]     The handle  18  may be of any type and may be mounted to any appropriate structure, such as the support structure  16  or the air tank  14 . In the particular embodiment illustrated, the handle  18  is fixedly mounted to air tank  14  and includes a grip portion  96  ( FIG. 12 ) that is contoured to receive the fingers of the user when the user is transporting the air compressor package  10   d . The grip portion  96  ( FIG. 12 ) is formed about a centerline  98  that lies in (or is positionable into) a plane (e.g., plane  324 ) that includes the center of gravity CG ACP  of the air compressor package  10   d.    
         [0072]     The handle  18  permits the user of the air compressor package  10   d  to reposition the air compressor package  10   d  from the operational position that is illustrated in  FIG. 14  to a transport position that is similar to that which is illustrated for the air compressor package  10  in  FIG. 7 . In the transport position, the user may carry the air compressor package  10   d  with the lower surface of the base member  310  positioned proximate their lateral side or in the alternative, with the shroud  330  is positioned proximate their lateral side. In the particular example provided, the dimension between the first plane  324  and the tubular supports  30   d  is not equal to the dimension between the first plane  324  and the lower surface of the base member  310 . Construction in this manner permits the user to transport the air compressor package  10   d  in two distinct manners. Since the air tank  14  is placed directly onto the base member  310  of the mounting platform  34   d , the center of gravity CG ACP  of the air compressor package  10   d  is relatively closer to the base member  310  as compared to the embodiments of  FIGS. 3 through 11  and as such, some users will find the air compressor package  10   d  more easy to transport than the air compressor package  10  of  FIG. 3 , since this configuration permits the air compressor package  10   d  to be transported relatively closer to the lateral side of a user.  
         [0073]     As will be apparent to one of ordinary skill in the art in light of this disclosure, placement of the air compressor package  10   d  in the operating position places the axis  302  along which the piston  300  ( FIG. 12 ) reciprocates in a generally horizontally orientation, while placement of the air compressor package  10   d  in the transport position places the axis  302  in a generally vertical orientation.  
         [0074]     An alternative arrangement for an air compressor package  120  constructed in accordance with the teaching of the present invention is depicted in  FIGS. 15 through 20 . In this embodiment, an air compressor mechanism  122  is mounted between a pair of cylindrically shaped air tanks  124 . As shown, the air tanks are spaced apart laterally from each other and supported on the underside by a pair of skid bars  126 . The skid bars  126  are likewise spaced apart laterally from each other, but mounted transversely to the two air tanks  124 . A rubber foot  128  is affixed to each end of each skid bar  126 . These rubber feet  128  serve to dampen vibrations that are transmitted through the support structure during operation as well as provide a degree of skid resistance when placed in an operational position.  
         [0075]     As described above, the air compressor mechanism  122  further comprises a compressor  132  operable to intake and compress ambient air and a power source  134 , such as an electric motor or an engine, for providing power to the compressor. The compressor mechanism is again of a conventional construction and operation and as such does not need to be described in further detail.  
         [0076]     A shroud assembly  140  protects the compressor mechanism and associated components should the air compressor package  120  be overturned or impacted by another object. In an exemplary embodiment, the shroud assembly  140  includes a protective plate  142  extending between a pair of inverted u-shaped tubular members  144 . Ends of the tubular members  144  are coupled by conventional means, such as welds, to the top surface of the air tanks  124 . The protective plate is in turn coupled to the tubular members  144 . The protective plate is formed from a sheet or material, such as steel, aluminum, plastic or other suitable material, and is removably fastened with, for example, conventional threaded fasteners to the tubular frame.  
         [0077]     A portion of the protective plate serves as a gauge panel  146  which supports conventional compressor accessory components, such as pressure gauges, a pressure regulator and one or more outlet manifolds. The gauge panel  146  is preferably sloped rearwardly in a manner that improves readability and accessibility of the gauges housed in the panel.  
         [0078]     To transport the air compressor package  120 , a handle extends outwardly from either side of the air compressor package  120 . In the exemplary embodiment, the handle  150  is a tubular member which extends between the two u-shaped tubular members  144 . It is contemplated that the handle  150  may include a grip portion that is contoured to receive the user&#39;s fingers. It is also contemplated that the handle may have other configurations and be mounted to other appropriate support structure, such as one of the air tanks. Again, the grip portion is preferably formed about a centerline that lies in (or is positionable into) a plane that includes the center of gravity CG ACP  of the air compressor package  120 . The handle  150  enables the user to rotate the air compressor package  120  to an intermediate position as shown in  FIG. 21  prior to reaching a transport position as shown in  FIG. 22 .  
         [0079]     Protective stops  152  are again used to prevent any unwanted slippage of the air compressor package away from the user. In this embodiment, the protective stops  152  are fastened to the air tank disposed on an opposite side from the handle  150 . More specifically, the protective stops  152  are fastened to a mounting bracket  154  which in turn is coupled to the air tank by conventional means, such as welds, as best seen in  FIG. 20 . The protective stops  69  are preferably comprised of rubber or some other type of material having an adhesive characteristic. The protective stops  152  also protect the air tank from the rough surface and/or abrupt landings which may be encountered as the air compressor package is returned to an operational position.  
         [0080]     When positioned in the transport position, the plane  160  that includes the centerline  162  of the handle  150  and a center of gravity CG ACP  of the air compressor package  120  is located in a substantially vertical orientation that is generally parallel to a vertical (longitudinal) axis  104  of the user  94 , as well as generally parallel to a base and a top  108  of the air compressor package  120 . Furthermore, since the center of gravity CG ACP  of the air compressor package  120  is relatively close to the base when the air compressor package  120  is oriented in the operational position, the user  94  is able to transport the air compressor package  120  such that the base is proximate a lateral side  110  of the user  94  (i.e., within about 10 inches of the lateral side  110 , and preferably about 3 inches to about 7 inches) and the user&#39;s wrist  112  is not in a state of flexion. With the handle  150  thus positioned, the user  94  is able to comfortably carry the air compressor package  120 , as well as to easily pivot the air compressor package  120  between the operational position and the transport position without releasing the handle  150 .  
         [0081]     With reference to  FIGS. 23 through 25 , another air compressor package constructed in accordance with the teachings of the present disclosure is generally indicated by reference numeral  500 . The air compressor package  500  can include a compressor mechanism  512 , an air tank  514 , a support structure  516 , a handle  518  and a gauge package  520 . The compressor mechanism  512  can be conventional in its construction and operation and as such, need not be discussed in detail herein. In the particular example provided, the compressor mechanism  512  is generally similar to the compressor mechanism  12  associated with the embodiment of  FIGS. 12 and 13 . In this regard, the compressor mechanism  512  includes an oil-less compressor that is driven by an electric motor.  
         [0082]     The air tank  514  may have a capacity of at least 0.5 gallons and in the particular example provided, is illustrated as having a single cylindrically shaped tank structure. The air tank  514 , however, may have a capacity of about 1 to about 8 gallons, e.g., a capacity of about 3 to about 5 gallons.  
         [0083]     The support structure  516  can be configured in a “roll-cage” manner that extends around both the compressor mechanism  512  and the air tank  514  to protect these components should the air compressor package  500  be overturned or impacted by another object. In the particular embodiment illustrated, the support structure  516  includes a tubular frame  530  having opposite laterally extending sides  532  and the handle  518 , which interconnects the opposite laterally extending sides  532 . The support structure  516  can further include a plurality of strut members  536 , as well as an optional shield or cover  538  and a plurality of fastening tabs  539  ( FIG. 25 ). The strut member  536  can be welded to the laterally extending side members  532  and can be fixedly but removably coupled to the compressor mechanism  512  via threaded fasteners (not shown) in a conventional and well known manner.  
         [0084]     In the example provided, the laterally extending sides  532  are constructed to include a first leg  580 , a second leg  582  and an arm  584  that is disposed between and interconnects the first and second leg  582 . The first leg  580  can be received under a first side of the compressor mechanism  512  and under the air tank  514  to support compressor mechanism  512  and air tank  514 . The second leg  582  can include a first portion  586 , which can be coupled to the arm  584  and which can be generally parallel to the first leg  580 , and a second portion  588  that interconnects the handle  518  and the first portion  586 . The second portion  588  can extends downwardly toward the first leg  580  and outwardly beyond the air tank  514  toward the handle  518 . It will be appreciated that the air tank  514  has a generally cylindrical shape and extends longitudinally between the side members  532  such that the air tank  514  abuts the first legs  580  and the second portion  588  of the second legs  582 .  
         [0085]     The cover  538  can be formed from a sheet material, such as steel, aluminum or plastic. The fastening tabs  529  can be welded to the tubular frame  530  and can include a threaded aperture (not shown). In the alternative, the fastening tabs  529  can include a through-hole (not specifically shown) that can be aligned to a thread form (not specifically shown) that is defined by a sheet metal clip  541  ( FIG. 25 ) that can be engaged to an associated fastening tab  529 . In either arrangement, the cover  538  can be coupled to the tubular frame  530  via conventional fasteners (not specifically shown), but the sheet metal clips  541  ( FIG. 25 ) are advantageous in that they are relative less expensive and more tolerant of manufacturing variation. While the primary purpose of the cover  538  is to protect components such as the compressor mechanism  512  and the gauge package  520  from damaging contact with, for example, falling tools and workpieces, those skilled in the art will understand that the relatively smooth outer surface of the cover  538 , when abutted against the lateral side of the user during transport, is relatively more comfortable and less likely to interfere with the movement of the user as compared to the tubular frame  530 , the compressor mechanism, the air tank  514  and/or the gauge package  520 .  
         [0086]     The gauge package  520  can include an air tank pressure gauge  546 , a user-adjustable regulator valve  548 , a regulator gauge  550  and an outlet manifold  552 , is coupled to a gauge panel  554  that is mounted between the laterally extending sides  532  of the support structure  516 . The gauge panel  554  may be a discrete component or may be integrally formed with the cover  538 . Preferably, the gauge panel  554  is mounted in a rearwardly sloped orientation, which is best illustrated in  FIG. 23 , as opposed to the substantially vertical orientation that is illustrated in the prior art air compressor package  1  of  FIG. 1 , so as to position the air tank pressure gauge  546 , the regulator  548 , the regulator gauge  550  and the outlet manifold  552  in a manner that is relatively more comfortable for the user of the air compressor package  500  to read and/or access. As those skilled in the art will appreciate from this disclosure, the improved readability of the air tank pressure gauge  546  and the regulator gauge  550  and the improved accessibility of the regulator  548  that result from the positioning of the gauge panel  554  in a rearwardly sloped orientation improves the accuracy with which the user is able to control the air pressure that is delivered to the outlet manifold  552 . Pegs  558 , which are coupled to one of the laterally extending sides  532  and extend outwardly therefrom, are optionally provided so as to permit items, such as a power cord  560  or an air hose (not shown), to be coiled around the pegs  558  for storage.  
         [0087]     A plurality of resilient feet  568  can be affixed to the corners of the tubular frame  530  and serve to dampen vibrations that are transmitted through the support structure  516  as well as to provide the support structure  516  with a degree of skid resistance.  
         [0088]     With reference to  FIGS. 24 and 26 , the air compressor package  500  is also shown to include a manifold  600 . The manifold  600  can include a manifold body  602  that can have a threaded portion  604  that is adapted to be threadably coupled to the air tank  514 . The manifold body  602  can define an inlet port  610 , an outlet port  612 , a pressure port  614 , a relief port  616 , and a drain port  618 . The inlet port  610  is coupled in fluid connection to the compressor mechanism  512  and the air tank  514 . Outlet port  612  is coupled in fluid connection to the air tank  514  and the pressure regulator valve  548 . Pressure port  614  is coupled in fluid connection to the air tank  514  and a pressure switch  615  that is associated with the compressor mechanism  512 . Relief port  616  is coupled in fluid connection to the air tank  514  and a relief valve  617 . Drain port  618  is coupled in fluid connection to the air tank  514  and a drain valve  619 . In the particular example provided, the manifold body  602  is unitarily formed from a suitable material, such as zinc, e.g., in a casting process (e.g., die casting) and can be, e.g., machined as necessary thereafter.  
         [0089]     With reference to  FIGS. 27 and 28 , the inlet port  610  can include a first coupling  650  and an outlet zone  652  that is disposed within an annular cavity  654  that is defined by a wall member  656  of the manifold body  602 . The first coupling  650  is illustrated to include female pipe threads, but those of ordinary skill in the art will appreciate that any other coupling means (e.g., male pipe threads, quick couplings, a hose barb, flare fittings or interfaces) may be employed.  
         [0090]     The outlet port  612  can include an inlet zone  662 , which is disposed within the annular cavity  654 , and a second coupling  664 , which is illustrated to include a male hose barb. Those of ordinary skill in the art will appreciate that any other coupling means (e.g., male pipe threads, quick couplings, a hose barb, flare fittings or interfaces) may be employed. In the example provided, the outlet port  612  is segregated or separate from the inlet port  610  (e.g., the hole formed in the manifold body  602  that defines the inlet port  610  can be formed separately from the hole in the manifold body  602  that defines the outlet port  612 ). Construction in this manner permits air from the compressor mechanism  512  ( FIG. 22 ) to be directed into the air tank  514  ( FIG. 22 ) rather than toward the outlet port  612 .  
         [0091]     With reference to  FIGS. 27 and 29 , the pressure port  614  can include a third coupling  670 , such as a male hose barb, and can intersect the outlet port  612  or the cavity  654  to permit air from the air tank  514  ( FIG. 24 ) to operate the pressure switch  615  ( FIG. 26 ) that is associated with the compressor mechanism  512  ( FIG. 24 ). As those of ordinary skill in the art will appreciate, the pressure switch  615  ( FIG. 26 ) is employed to actuate the power source that operates the compressor mechanism  512  ( FIG. 24 ) when the air pressure in the air tank  514  ( FIG. 24 ) is less than a predetermined air pressure threshold.  
         [0092]     The relief port  616  can include a fourth coupling  674 , such as female pipe threads, and can intersect the outlet port  612  or the cavity  654  to permit air from the air tank  514  ( FIG. 24 ) to act on the relief valve  617  ( FIG. 26 ). As those of ordinary skill in the art will appreciate, the relief valve  617  ( FIG. 26 ) can be a normally closed valve that opens when the air pressure that is acting on it is greater than a predetermined air pressure.  
         [0093]     With reference to  FIGS. 27 and 30 , the drain port  618  can be formed in the manifold body  602  such that drain port  618  is fluidly isolated from the inlet port  610 , the outlet port  612 , and the cavity  654 . In the particular example provided, the drain port  618  is formed in a portion of the manifold body  602  so as not to intersect the cavity  654  that is defined by the wall member  656 . The drain port  618  includes a central portion  680 , which extends longitudinally through the manifold body  602 , an inlet  682 , which is formed through a portion of the wall member  656 , and an outlet  684 . The outlet  684  can include a fifth coupling  686 , such a female pipe threads.  
         [0094]     With reference to  FIGS. 31 and 32 , the manifold  600  is installed to the air tank  514  such that the inlet  682  of the drain port  618  is disposed below an end  700  of the manifold body  602  through which the inlet port  610  and the outlet port  612  ( FIG. 27 ) communicate with the air tank  514  when the air compressor package  500  ( FIG. 24 ) is positioned in an operating position, which is illustrated in  FIG. 22 . The drain valve  619 , which can be a conventional ball valve, can be coupled to the outlet  684  of the drain port  618 . Configuration of the manifold  600  in this manner permits fluids that have accumulated in the air tank  514  to drain into the drain port  618  and not into the inlet port  610 , the outlet port  612  ( FIG. 27 ), the pressure port  614  ( FIG. 27 ) or the relief port  616 . As such, the various ports may be combined into a single manifold that is attached to the air tank  514  at a single location, which is relatively less expensive to manufacture than an air tank that employs multiple mounting locations for the various ports.  
         [0095]     While specific examples have been described in the specification and illustrated in the drawings, it will be understood by those of ordinary skill in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the present disclosure as defined in the claims. Furthermore, the mixing and matching of features, elements and/or functions between various examples is expressly contemplated herein so that one of ordinary skill in the art would appreciate from this disclosure that features, elements and/or functions of one example may be incorporated into another example as appropriate, unless described otherwise, above. Moreover, many modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from the essential scope thereof. Therefore, it is intended that the present disclosure not be limited to the particular examples illustrated by the drawings and described in the specification as the best mode presently contemplated for carrying out this disclosure, but that the scope of the present disclosure will include any embodiments falling within the foregoing description and the appended claims.