Patent Publication Number: US-2019184803-A1

Title: Component mount and chassis incorporating same

Description:
FIELD OF THE INVENTION 
     This invention generally relates to motor vehicles, and more particular to chassis and motor mount design. 
     BACKGROUND OF THE INVENTION 
     Standard construction of a relatively larger motor vehicle such as a motor home or a passenger bus typically requires construction of a chassis that may typically provide the mechanical workings of such vehicles. The chassis will typically carry the suspension, the engine, transmission, etc. To achieve this, additional mounting structures or “mounts” are utilized to mount many of such componentry. 
     For example, motor mounts may be used for mounting the motor to the chassis, and more particularly the frame rails of the chassis, to support the motor. The same holds true for the transmission. In either case, the mounts themselves must be of a robust construction to support the weight and loading characteristics of such large and heavy mechanical devices and must also provide a vibration dampening function such that undamped vibrations are not transferred from the chassis to these devices and vice versa. 
     As a result, such mounts are relatively complex in nature. They typically involve a frame rail side portion and a component (e.g. an engine or a transmission) side portion. Damping elements are used to connect the frame rail side portion to the component side portion in an effort to reduce or eliminate mechanical vibrations between these components. 
     One example of such a complex configuration includes a chassis having a pair of frame rails. A pair of component mounts are used to connect an engine or other component to the frame rails. These mounts are relatively large. As introduced above, they include a frame rail side portion and a component side portion. A pair of damping element assemblies is positioned between the aforementioned portions. The upper portions of these damping element assemblies is exposed above an upper surface of the component side portion of each mount. These damping element assemblies are secured to the component side and frame rail side portions via bolt respectively, which extends through the damping element assemblies. The ends of these bolts face upwardly given that the bolts extend generally perpendicular to the length of the frame rails. 
     As such, in order to decouple the frame rail side portion from the component side portion, these bolts must be removed. Such decoupling is necessary when it is desirable to remove the engine or other component, and is also a prerequisite to installing the engine or other component. As such, such bolts must be readily accessible in the direction which is perpendicular to the length of the frame rail. 
     The frame rails themselves have a U-shaped cross section such that upper and lower flanges extend laterally into the space between the rails. The component mounts are situated between the flanges and mount to an interior surface of the frame rails. To facilitate access to the aforementioned bolts, the upper flange must include a cut out to unmask the otherwise hidden bolts of the component mounts. The upper flange would otherwise cover (and thus prevent access to) the mounts if the cut outs were not present. 
     Unfortunately, due to the larger size of the component mounts, the cut outs themselves must be relatively large and thus must be formed after the U-shaped cross section of the frame rails is implemented. In other words, the frame rails are first bent into shape, and then the cut outs are formed. 
     This forming is typically done via torch cutting, and is done in close proximity to a stress concentration region in the frame rails, i.e. the bend near the upper flange. Given that torch cutting is itself a stress inducing process, the region of the cut outs has a tendency to be a high residual stress region after being bent and then subjected to torch cutting. This can lead to stress fractures in the frame rails in the region of the cut outs in the field. 
     On approach to avoiding the above residual stresses has been to omit the cut out entirely. This, however, means that the component mounts must first be disconnected from the component entirely prior to removing the component mounted by the mounts. In the example of an engine, the component mounts must first be disconnected from the component in order to remove the engine. Given that the bolts which mount the component mount to the component are in a very difficult space to reach by hand (and even more difficult with a tool), this approach is undesirable. 
     Accordingly, there is a need in the art for a component mount and a chassis incorporating the same which does not require such large cut outs to provide access to the component mount. The invention provides such a component mount and chassis incorporating same. These and other advantages of the invention, as well as additional inventive features, will be apparent from the description of the invention provided herein. 
     BRIEF SUMMARY OF THE INVENTION 
     In one aspect, the invention provides a component mount for use with a chassis assembly. An embodiment of such a component mount includes a frame rail side configured for mounting to a frame rail of a chassis. The frame rail side portion includes a partition plate. This embodiment also includes a component side portion configured for connection to a component. At least one upper damping element extends above the partition plate. At least one lower damping element is axially aligned with the at least one upper damping element about a common longitudinal axis. The at least one lower damping element extends below the partition plate such that the partition plate is interposed between the at least one upper damping element and the at least one lower damping element. 
     In certain embodiments, the at least one upper damping element includes a first bore and the at least one lower damping element includes a second bore. The first and second bores are axially aligned with one another to receive a fastener. A sleeve surrounds the fastener within the first and second bores. 
     In certain embodiments, the at least one upper damping element and the at least one lower damping element each have a first portion having a first outer diameter and a second portion having a second outer diameter less than the first outer diameter. The component mount may also include a spacer plate in contact with the partition plate. The second portion of the at least one upper damping element extends into a bore of one of the spacer plate or the partition plate. The second portion of the at least one lower damping element extends into a bore of the other one of the spacer plate and or partition plate. The bore of the spacer plate and the bore of the partition plate are aligned with one another. 
     In certain embodiments, a gap is formed between an axial face of the second portion of the at least one upper damping element and an axial face of the second portion of the at least one lower damping element. 
     In certain embodiments, the component mount also includes a pair of washer plates, wherein the at least one upper damping element and the at least one lower damping element are interposed between the pair of washer plates. 
     In certain embodiments, the at least one upper damping element includes a plurality of upper damping elements, and the at least one lower damping element includes a plurality of lower damping elements. The plurality of upper damping elements are arranged in a row. The plurality of lower damping elements are arranged in a row. Each one of the plurality of upper damping elements is aligned with each one of the lower damping elements, respectively. 
     In another aspect, the invention provides a chassis assembly for a motor vehicle. An embodiment of such a chassis assembly includes a pair of opposed frame rails each having a U-shaped cross section with a base section and upper and lower flanges extending from the base section in an opposed spaced relationship. This embodiment also includes at least one pair of opposed component mounts. Each component mount includes a frame rail side portion configured for mounting to an interior surface of the base section. 
     This embodiment also includes a component side portion configured for connection to a component. The component side portion includes a mounting wall for mounting to the base section of the frame rail and a support wall extending transverse to the mounting wall. This embodiment also includes at least one upper damping element interposed between the frame rail side portion and the component side portion as well as at least one lower damping element interposed between the frame rail side portion and the component side portion. 
     The at least one lower damping element is axially aligned with the at least one upper damping element about a common longitudinal axis defined by the aligned at least one upper damping element and the at least one lower damping element. The at least one upper damping element is situated axially above the at least one lower damping element relative to the common longitudinal axis. The at least one upper damping element and the at least one lower damping element are entirely below the support wall relative to the common longitudinal axis. 
     In certain embodiments, the at least one upper damping element includes a first bore and the at least one lower damping element includes a second bore. The first and second bores are axially aligned with one another to receive a fastener. A sleeve surrounds the fastener within the first and second bores. 
     In certain embodiments, the at least one upper damping element and the at least one lower damping element each have a first portion having a first outer diameter and a second portion having a second outer diameter less than the first outer diameter. The component mount may also include a spacer plate in contact with the partition plate. The second portion of the at least one upper damping element extends into a bore of one of the spacer plate or the partition plate. The second portion of the at least one lower damping element extends into a bore of the other one of the spacer plate and or partition plate. The bore of the spacer plate and the bore of the partition plate are aligned with one another. 
     In certain embodiments, a gap is formed between an axial face of the second portion of the at least one upper damping element and an axial face of the second portion of the at least one lower damping element. 
     In certain embodiments, the component mount also includes a pair of washer plates, wherein the at least one upper damping element and the at least one lower damping element are interposed between the pair of washer plates. 
     In certain embodiments, the at least one upper damping element includes a plurality of upper damping elements, and the at least one lower damping element includes a plurality of lower damping elements. The plurality of upper damping elements are arranged in a row. The plurality of lower damping elements are arranged in a row. Each one of the plurality of upper damping elements is aligned with each one of the lower damping elements, respectively. 
     In yet another aspect, a method for forming a chassis assembly of a motor vehicle is provided. An embodiment of this method includes of a motor vehicle providing a pair of frame rails, which includes first forming a cut out in a flat sheet and subsequently bending the flat sheet after forming the cut out into the frame rail. The resultant bent frame rail has a U-shaped cross section after bending with a base section and opposed upper and lower flanges, with the cut out being situated in the upper flange. This embodiment also includes mounting a pair of component mounts to the pair of frame rails, respectively, such that each component mount is accessible through each cut out of each frame rail. 
     In certain embodiments, the step of providing the pair of frame rails includes forming the cut out such that the upper flange has a reduced width in the region of the cut out. 
     In certain embodiments, the step of mounting the pair of component mounts to the pair of frame rails, respectively, includes, for each one of the pair of component mounts, mounting a frame rail side portion to the base section of the component mount and mounting a component to a component side portion of the component mount. The component mount includes at least one upper damping element and at least one lower damping element. The frame rail side portion includes a partition plate is interposed between the at least one upper damping element and the at least one lower damping element. 
     Other aspects, objectives and advantages of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention and, together with the description, serve to explain the principles of the invention. In the drawings: 
         FIG. 1  is a perspective view of an embodiment of a chassis assembly which incorporates an embodiment of a component mount according to the teachings herein; 
         FIG. 2  is a perspective view of the component mount of  FIG. 1 ; 
         FIG. 3  is an exploded view of the component mount of  FIG. 2 ; 
         FIG. 4  is a cross section of the component mount of  FIG. 2 ; 
         FIG. 5  is a perspective view of another embodiment of a chassis assembly which incorporates another embodiment of a component mount according to the teachings herein; 
         FIG. 6  is a perspective view of the component mount of  FIG. 5 ; 
         FIG. 7  is an exploded view of the component mount of  FIG. 6 ; 
         FIG. 8  is a cross section of the component mount of  FIG. 6 ; and 
         FIG. 9  is a perspective view of the chassis assembly of  FIG. 1 , illustrating a cut out formed in the frame rails of the chassis assembly; and 
     
    
    
     While the invention will be described in connection with certain preferred embodiments, there is no intent to limit it to those embodiments. On the contrary, the intent is to cover all alternatives, modifications and equivalents as included within the spirit and scope of the invention as defined by the appended claims. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Turning now to the drawings, the same illustrate embodiments of a chassis assembly and a component mount associated with the chassis assembly. The component mount has compact design compared to prior designs. This in turn allows a frame rail of chassis assembly attached to utilize a much smaller cut out for accessing the component mount in comparison to those prior designs discussed above that incorporate a larger cut out. Because this cut out is much smaller, it may be implemented prior to bending the frame rail into its U-shaped cross sectional shape, instead of after bending the frame rail into its U-shaped cross sectional shape as is done in prior designs. This significantly reduces the residual stresses in that region. 
     Turning now to  FIG. 1 , a chassis assembly  20  (hereinafter referred to as assembly  20 ) according to the teachings herein is illustrated. Assembly  20  includes a pair of opposed frame rails  22 ,  24  each having a U-shaped cross-section as illustrated. Although not shown, it will be readily recognized that assembly  20  also includes lateral support members extending between frame rails  22 ,  24  and other componentry typical of chassis designs. For purposes of describing the invention, however, these additional components are not shown as they are not necessary for the description herein. 
     A pair of component mounts  26 ,  28  are mounted to each frame rail  22 ,  24 , respectively. More specifically, each frame rail includes a base section  34  and upper and lower flanges  36 ,  38 . The term “lower” in the context of lower flange  38  is used to denote the flange which is closest to a road surface during operation of a vehicle incorporating assembly  20 . The term “upper” in the context of upper flange  36  is used to denote the flange which is vertically above lower flange  38 . With particular reference to component mount  26 , the same mounts directly to base section  34  as shown. An identical configuration is also present for frame rail  24  and component mount  28 . As such, any description of one component mount applies equally well to the other, and any description of one frame rail applies equally well to the other. 
     Component mount  26  includes a frame rail side portion  40  and a component side portion  42  as shown. As may be surmised from  FIG. 1 , frame rail side portion  40  is configured to mount to frame rail  22 , and more particularly, base section  34  as mentioned above. To configure frame rail side portion  40  to achieve such mounting, the same may include a hole pattern or the like for receiving bolts which pass through frame rail  22  to join frame rail side portion  40  to frame rail  22 , as one non-limiting example. Further, frame rail side portion  40  may incorporate a generally flat surface to allow for flush mounting frame rail side portion  40  against frame rail  22 . 
     Similarly, component side portion  42  is configured to mount with or receive a component  30 . This configuration may be achieved by providing component side portion  42  with a hole pattern or the like for receiving bolts which are used to join component  30  to component side portion  42 . Further, component side portion  42  may incorporate a generally flat surface to allow for flush mounting component  30  against component side portion  42 . Of course, it is entirely possible to use other means of mechanical joining to join frame rail side portion  40  to frame rail  22  as well as component side portion  42  to component  30 . 
     Component  30  is illustrated in the form of an engine block. However, mounts  26 ,  28  may be utilized to mount any component typically mounted to a frame rail of a chassis. As will be discussed below, and as one non-limiting example, the teachings herein may be readily applied to a mount for mounting a transmission to a frame rail as well. 
     Turning now to  FIG. 2 , the same illustrates component mount  26  disconnected from frame rail  22 . As already mentioned above, component mount  26  is identical to component mount  28 . For purposes of brevity, only component mount  26  is described herein. However, this description applies equally well to component mount  28 . As mentioned above, component mount  26  includes a frame rail side portion  40  and a component side portion  42 . 
     An interior space  46  is formed between these portions  40 ,  42 . A damping arrangement  48  is contained within interior space  46 . As will be described in greater detail below, this damping arrangement  48  includes at least one upper damping element and at least one lower damping element which is axially aligned with the upper damping element. Bolts  50  are utilized to fasten frame rail side portion  40  to component side portion  42 . Frame rail side portion  40  employs one or more bolt holes  52  for connecting to frame rail  22  as discussed above. Similarly, component side portion  42  includes one or more bolt holes  54  for connecting frame rail side portion to component  30  (see  FIG. 1 ). 
     Turning now to  FIG. 3 , component mount  26  is illustrated in an exploded view. As mentioned above, damping arrangement  48  (see  FIG. 2 ) includes at least one upper damping element  60  and at least one lower damping element  62 . In the illustrated embodiment, there are two identical upper damping elements  60  and two identical lower damping elements  62 . In other embodiments, there may only be a single upper damping element and a single lower damping element, or alternatively as shown in  FIGS. 5-8 , more than two upper damping elements and more than two lower damping elements. The number of upper and lower damping elements is entirely dependent upon the expected loading of component mount  26 , as well as the desired damping characteristics. 
     As may be seen from  FIG. 3 , upper damping element  60  is aligned with lower damping element  62  to define a common longitudinal axis  64 . As its name implies, upper damping element  60  is axially above lower damping element  62  relative to longitudinal axis  64 . Each pair of upper and lower damping elements employs the same aligned arrangement described above. 
     Upper damping element  66  includes a bore extending therethrough. Similarly, lower damping element  62  includes a bore  68  extending therethrough. These bores  66 ,  68  are aligned along longitudinal axis  64  to receive bolts  50  as illustrated. Bolts  50  extend through upper and lower damping element  60 ,  62  and are tightened via nuts  56  as shown. Additionally, a sleeve  72  may extend through bores  66 ,  68  to receive bolts  50  as illustrated. 
     Component side portion  42  includes a mounting portion  74  and a support portion  76  which extends generally transverse to mounting portion  74 . Support portion  76  exerts a downward force against upper and lower damping elements  60 ,  62  as bolts  50  are tightened. Although not a requirement, washer plates  78  may also be employed to uniformly distribute the force exerted against upper and lower damping elements  60 ,  62 . To this end, each washer plate  78  include bores  82  therethrough for the passage of fasteners  50 . 
     A partition plate  70  of frame rail side portion  40  is interposed between upper and lower damping element  60 ,  62  as shown. In this way, frame rail side portion  40  is linked or connected to component side portion  42 . Partition plate  70  includes bores  96  which are aligned with longitudinal axes  64 . These bores  96  receive a portion of lower damping elements  62  as described below, and also allow for passage of bolts  50  through partition plate  70 . 
     Frame rail side portion  40  includes a mounting portion  84  through which the above-introduced bolt holes  52  are formed. A pair of side portions  86  depend outwardly from mounting portion  84  as shown. Each side portion  86  includes a slot  88  for receipt of corresponding tabs  90  formed in partition plate  70 . Additionally, mounting portion  84  includes a slot  92  for receipt of a corresponding tab  94  of partition plate  70 . Tabs  90 ,  94  may be press fit, welded, braised or fixed in place in their corresponding slots  88 ,  92  using any other known mechanical connection. 
     Additionally, a spacer plate  102  may be positioned on top of partition plate  70  as shown. Spacer plate  102  includes bores  104  therethrough aligned along longitudinal axes  64 . These bores  104  receive a portion of upper damping elements  60  as described below, as well as permit passage of bolts  50  therethrough. It should be noted that while spacer plate  102  is illustrated as a separate component from partition plate  70 , partition plate  70  and spacer plate  102  may be formed as a single unitary component in other embodiments. Further, spacer plate  102  may simply rest upon a top surface of partition plate  70 , or it may be fixed to partition plate  70  using any known mechanical joining means. 
     Turning now to  FIG. 4 , the same illustrates a cross-section taken through upper and lower damping element  60 ,  62 . Lower damping element  62  includes a first portion  110  and a second portion  112  extending axially from first portion  110 . Second portion  112  has a smaller outer diameter than first portion  110 . Second portion  112  is received within bores  96  of partition plate  70 . 
     Similarly, upper damping element  60  includes a first portion  114  and a second portion  116  depending axially from first portion  114 . Second portion  116  has an outer diameter which is smaller than an outer diameter of first portion  114 . Second portion  116  is received within bores  104  of spacer  102  as may be seen in  FIG. 4 , second portion  112  of lower damping element  62  includes an axial face  118  which faces an axial face  120  of second portion  116  of upper damping elements  60 . A gap is formed between these axial faces  118 ,  120  to allow for expansion of upper and lower damping elements  60 ,  62  during loading. 
     The overall construction of component mounts  26 ,  28  as well as the arrangement of upper and lower damping elements  60 ,  62  allows for utilizing a smaller outer diameter for first portions  110 ,  114  compared to prior designs. Indeed, prior designs typically employ damping elements ranging in outer diameter from about 2.5 inches to about 4 inches, whereas first portions  110 ,  114  may employ an outer diameter of about 2 inches. The term “about” is used in the context to allow for typical manufacturing tolerances in damping element design. 
     Turning now to  FIGS. 5-8 , the same illustrate an alternative embodiment of a chassis assembly  220  (hereinafter referred to as assembly  220 ). With particular reference to  FIG. 5 , assembly  220  includes a pair of identical frame rails  222 ,  224 . As such, a description of one frame rail  222 ,  224  applies equally well to the other. A pair of identical component mounts  226 ,  228  are mounted to frame rails  222 ,  224 , respectively. Component mounts  226 ,  228  are identical to one another. As such, a description of one applies equally well to the other. These component mounts  226 ,  228  are similar in construction to component mounts  26 ,  28  described above with notable differences discussed below. Component mounts  226 ,  228  are used to mount a component  230  to assembly  220 . In this particular embodiment, the component in this instance is a transmission. 
     Each frame rail has a U-shaped cross-section and includes a base section  234 , with upper and lower flanges  236 ,  238  depending inwardly from base section  234  as shown. With exemplary reference to component mount  226 , the same includes a frame rail side portion  240  which is configured to mount to base section  234  of frame rail  222 , as well as a component side portion  242  which is configured to mount to component  230 . Frame rail side portion  240  and component side portion  242  are configured to mount to frame rail  222  and component  230 , respectively, in the same manner as described above relative to frame rail side portion  40  and component side portion  42 . 
     Turning now to  FIG. 6 , component mount  226  is shown in a perspective view. An interior space  246  is formed between frame rail side portion  240  and component side portion  242 . A damping arrangement  248  is positioned within interior space  246 . This damping arrangement  248  is identical to damping arrangement  48  described above, except for the differences discussed below. 
     Frame rail side portion  240  includes a plurality of bores  252  for receiving bolts used to mount frame rail side portion  242  frame rail  222  (see  FIG. 5 ). Similarly, component side portion  242  includes a plurality of bores  254  for receiving bolts for mounting component  230  (see  FIG. 5 ) to component side portion  242 . 
       FIG. 7  illustrates component mount  226  in an exploded view. As will be immediately apparent from inspection of  FIG. 7 , the same incorporates three upper damping elements  260  and three lower damping elements  262 . Each upper damping element  260  is aligned with a corresponding lower damping element  262  in the same manner as described above relative to  FIG. 3 . As such, each aligned pair of upper damping element  260  and lower damping element  262  defines a common longitudinal axis  264  as shown. Upper and lower damping element  260 ,  262  each include a bore  266 ,  268 , respectively, therethrough for receipt of bolts  250 . A sleeve  272  may also be positioned within these aligned bores  266 ,  268  for receiving the corresponding bolt  250 . 
     Component side portion  242  includes a mounting portion  274  and a support portion  276  extending transverse to mounting portion  274 . Support portion  276  exerts a downward force against upper and lower damping elements  260 ,  262  as bolts  250  are tightened via tightening of nuts  256 . Although not a requirement, washer plates  278  may also be utilized to distribute the loading evenly across upper and lower damping element  260 ,  262 . To this end, each washer plate  278  includes corresponding bores  282  which are aligned along longitudinal axes  264  to allow for passage of bolts  250  therethrough. 
     A partition plate  270  of frame rail side portion  240  is interposed between upper and lower damping elements  260 ,  262  as shown. In this way, frame rail side portion  240  is linked or otherwise connected to the mounting portion  242 . 
     Frame rail side portion  240  includes a mounting portion  284  and a pair of side portions  286  depending outwardly from mounting portion  284 . Each side portion  286  includes a slot  288  which receives a corresponding tab  290  of partition plate  270 . Tabs  290  may be attached to slots  288  via any mechanical connection means. 
     Partition plate  270  includes a plurality of bores  296  each of which is aligned along a corresponding longitudinal axis  264 . As described below, a portion of upper damping elements  260  are respectively received within bores  296  of partition plate  270 . Bores  296  also permit passage of bolts  250  through partition plate  270 . 
     A spacer plate  302  may also be provided and is in contact with partition plate  270 . Spacer plate  302  includes a plurality of bores  304  each of which is respectively aligned along a corresponding longitudinal axis  264 . A portion of lower damping elements  262  extends into bores  304 . Bores  304  also permit passage of bolts  250  through spacer plate  302 . Although illustrated as a separate component, spacer plate  302  may be formed as a single unitary component with partition plate  270 . Further, spacer  304  may rest against partition plate  270  or may be fixed to partition plate  270  via any mechanical connection means. 
     Turning now to  FIG. 8 , the same illustrates a cross-section taken through upper and lower damping elements  260 ,  262 . Lower damping element  262  includes a first portion  310  and a second portion  312 . Second portion  312  has an outer diameter which is less than an outer diameter of  310 . Second portion  312  is received within bore  304  of spacer  302 . 
     Upper damping element  260  includes a first portion  314  and a second portion  316 . Second portion  316  has an outer diameter which is less than an outer diameter of first portion  314 . Second portion  316  is received within apertures  296  of spacer plate  270 . Second portion  312  of lower damping element  262  includes an axial face  318 . Second portion  316  of upper damping element  260  also includes an axial face  320  which faces axial face  318 . A gap is formed between these axial faces  318 ,  322  permit expansion of upper and lower damping elements  260 ,  262  during loading. 
     The overall construction of component mounts  226 ,  228  as well as the arrangement of upper and lower damping elements  260 ,  262  allows for utilizing a smaller outer diameter for first portions  210 ,  214  compared to prior designs. Indeed, prior designs typically employ damping elements ranging in outer diameter from about 2.5 inches to about 4 inches, whereas first portions  210 ,  214  may employ an outer diameter of about 2 inches. The term “about” is used in the context to allow for typical manufacturing tolerances in damping element design. 
     Turning now to  FIG. 9 , the same illustrates a partial view of assembly  20  illustrated in  FIG. 1 . A section of frame rail  22  is illustrated. As mentioned above, frame rail  22  is identical to frame rail  222  for purposes of this disclosure. As such, the following description applies equally well to frame rail  222  in the context of assembly  220 . A cutout  44  is implemented in top flange  36  as shown. Because of the compact design of component mount  26 , the depth of this cutout  44  is considerably less than prior designs. Indeed, flange  36  typically has a width W 1  outside of the region of cutout  44 . In the region of cutout  44 , however, flange  36  has a width W 2 . 
     The difference between widths W 1  and W 2  is about one half of an inch to about one inch. The term “about” in this instance is used to provide for typical manufacturing tolerances in chassis fabrication. Because of the relatively minimal nature of this cutout depth, it is now possible to bend frame rail  22  into its U-shaped cross-section after forming the cutout  44 . In other words, cutout  44  is implemented in a flat sheet. This flat sheet is then formed into the U-shaped cross-section to make frame rail  22 . 
     The foregoing order of operations of cutting and then bending has a significant advantage over prior designs. Indeed, as discussed above, with prior designs typically the cutout is implemented after the frame rail is formed into its U-shaped cross-section. In this method, a significant residual stress remains given the high stress nature of the cutting operation and given that there are already stress concentrations as a result of bending in the region of the bend. 
     As such, one exemplary method of forming a chassis assembly according to the teachings herein includes providing a pair of frame rails by first forming a cutout in a flat sheet and then subsequently bending the flat sheet after performing the cutout into the frame rail. Thereafter, the above discussed component mounts can be readily mounted to their associated frame rail. Such a configuration also allows for ready access to the component mounts from the top, i.e., the direction which is perpendicular to the length of the frame rails to readily disconnect component mounts from the remainder of the assembly. 
     All references, including publications, patent applications, and patents cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein. 
     The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) is to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention. 
     Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.