Patent Description:
When building trucks, a cab is typically mounted to a frame via a cab suspension that supports the cab proximate four corners of the cab. The suspension usually includes springs and dampers at each corner. A panhard bar is typically provided in connection with a rear portion of the suspension to resist lateral motion, provide stiffness to the cab suspension, and restrain the cab from detaching from the frame in the event of an accident.

As a result of variations from standard dimensions in cabs and frames due to, for example, permissible manufacturing tolerances, it is possible that a cab may not be properly oriented relative to the frame. For example, if the cab and frame design is such that wind resistance is minimized and/or fuel economy is maximized by a particular cab and frame orientation, such as by having longitudinal centerlines of the cab and frame aligned, a misalignment may increase wind resistance and/or be detrimental to fuel economy.

In addition to orientations of cab and frame that are less than optimal as the result of, e.g., manufacturing tolerances, the cab and frame may move from a desired orientation to a less desirable orientation after a period of use, such as due to wear to springs or other components. According to its abstract, <CIT> relates to a suspension system for a work vehicle including a rear suspension assembly that includes a first shock absorber assembly and a second shock absorber assembly, such that each of the first and second shock absorber assemblies has a first end that couples to a cab of the work vehicle and a second end that couples to a chassis of the work vehicle.

It is desirable to provide a way to correct the position a truck or tractor vehicle cab relative to a frame to place them in a desired angular orientation in spite of manufacturing tolerances, wear, or other factors that result in the cab and frame being oriented in a less than optimal manner. It is also desirable to be able to correct the position of the cab relative to the frame in a simple, inexpensive manner.

According to an aspect of the present invention, a truck or tractor vehicle comprises a frame having a longitudinal centerline, an operator cab mounted relative to the frame via a cab suspension, the cab having a longitudinal centerline, the cab suspension comprising a front suspension and a rear suspension, the rear suspension comprising an adjustable panhard bar attached at a first end to the cab and attached at a second end to the frame, the adjustable panhard bar being adjustable in length to position the longitudinal centerline of the cab at a desired angle relative to the longitudinal centerline of the frame.

According to another aspect of the present invention, a method for attaching a frame and an operator cab of a truck or tractor vehicle, the frame having a longitudinal centerline and the cab having a longitudinal centerline, comprises mounting the cab relative to the frame via a cab suspension, the cab suspension comprising a front suspension and a rear suspension, the rear suspension comprising an adjustable panhard bar attached at a first end to the cab and attached at a second end to the frame, the adjustable panhard bar being adjustable in length, and adjusting a length of the adjustable panhard bar to position the longitudinal centerline of the cab at a desired angle relative to the longitudinal centerline of the frame.

The features and advantages of the present invention are well understood by reading the following detailed description in conjunction with the drawings in which like numerals indicate similar elements and in which:.

A truck or tractor vehicle <NUM> according to an aspect of the present invention is shown in <FIG> and a frame <NUM> having a longitudinal centerline CF (<FIG> and <FIG>) and an operator cab <NUM> mounted relative to the frame via a cab suspension <NUM>, the cab having a longitudinal centerline CC (<FIG> and <FIG>). The cab suspension <NUM> comprises a front suspension <NUM> and a rear suspension <NUM>. As seen, for example, in <FIG>, the frame <NUM> typically comprises longitudinal portions (rails) <NUM> and transverse portions (cross members) 23t extending between the rails. The cab <NUM>, likewise, typically comprises longitudinal portions (cab rails) <NUM> and transverse portions (cab cross members) 25t extending between the cab rails.

As seen, for example, in <FIG>, the rear suspension <NUM> comprises an adjustable panhard bar <NUM> attached at a first end <NUM> to the cab <NUM> and attached at a second end <NUM> to a cross member 23t of the frame <NUM>. The adjustable panhard bar <NUM> is adjustable in length to position the longitudinal centerline CC of the cab <NUM> at a desired angle relative to the longitudinal centerline CF of the frame <NUM> as seen in <FIG> and <FIG>. The adjustable panhard bar <NUM> may be attached to one of the frame <NUM> and the cab <NUM> via a bracket or a suitable damping arrangement, such as the spring arrangement disclosed in <CIT>. In addition to the adjustable panhard bar <NUM>, the front suspension <NUM> and the rear suspension <NUM> will ordinarily include spring and damping members, such as shown in <CIT>, at at least the rear two and, ordinarily, at all four corners of the cab <NUM>.

The adjustable panhard bar <NUM> is ordinarily adjusted in length to position the longitudinal centerline CC of the cab <NUM> at a desired angle relative to the longitudinal centerline CF of the frame <NUM> so that wind resistance of the truck or tractor vehicle <NUM> is minimized and/or fuel economy is maximized. Ordinarily, wind resistance of the truck or tractor vehicle <NUM> is minimized and fuel economy is maximized by adjusting the adjustable panhard bar <NUM> in length to align the longitudinal centerline CC of the cab <NUM> and the longitudinal centerline CF of the frame <NUM>.

As seen, for example, in <FIG>, ordinarily, the adjustable panhard bar <NUM> comprises a first bar component <NUM> having a first end attachable to the frame <NUM> and a threaded second end <NUM>. The first end of the first bar component <NUM> is ordinarily the second end <NUM> of the adjustable panhard bar <NUM>. The adjustable panhard bar <NUM> ordinarily further comprises a second bar component <NUM> having a first end attachable to the cab <NUM> and a threaded second end <NUM>. The first end of the second bar component <NUM> is ordinarily the first end <NUM> of the adjustable panhard bar.

The threaded second end <NUM> of the first bar component <NUM> ordinarily has a first thread <NUM> having a first hand (e.g., left-hand), and the threaded second end <NUM> of the second bar component <NUM> ordinarily has a second thread <NUM> having a second hand opposite the first hand (e.g., righthand). A linking member <NUM> is provided and ordinarily has a first threaded end <NUM> with a thread <NUM> that mates with the threaded second end <NUM> of the first bar component <NUM> and a second threaded end <NUM> with a thread <NUM> that mates with the threaded second end <NUM> of the second bar component <NUM>. Ordinarily, the first and second threads <NUM> and <NUM> at the second threaded ends <NUM> and <NUM> of the first and second bar components <NUM> and <NUM>, respectively, are internal, or female, threads and the threads <NUM> and <NUM> at the first and second threaded ends <NUM> and <NUM> of the linking member <NUM> are external, or male, threads. As seen in <FIG>, it is, of course, also possible to provide a panhard bar <NUM> on which the first and second threads <NUM> and <NUM> at the second threaded ends <NUM> and <NUM> of the first and second bar components <NUM> and <NUM> are external threads and the first and second threads <NUM> and <NUM> at the first and second threaded ends <NUM> and <NUM> of the linking member <NUM> are internal threads. It is also possible to have one of the first and second threads at the second threaded end of the first and second bar components be an external thread and the other an internal thread, and mating ones of the first and second threads at the first and second threaded ends of the linking member be an internal thread and the other an external thread.

The linking member <NUM> ordinarily further comprises a central, unthreaded portion <NUM>. The central, unthreaded portion <NUM> ordinarily includes at least two opposite, longitudinally extending parallel surfaces <NUM>, such as surfaces on a square or hexagonal shape, for facilitating gripping by a conventional wrench or automatic tool. Depending upon which way the linking member <NUM> is turned relative to the stationary first bar component <NUM> and the stationary second bar component <NUM>, the length of the panhard bar <NUM> will increase or decrease because of the provision of the first thread <NUM> and the second thread <NUM> on the first and second bar components (and because of the threads <NUM> and <NUM> on the linking member) having opposite hands.

Ordinarily, the first end of the first bar component <NUM> (i.e. the second end <NUM> of the adjustable panhard bar <NUM>) and the first end of the second bar component <NUM> (i.e. the first end <NUM> of the adjustable panhard bar) each comprises a hole <NUM> and a bushing <NUM> in the hole. As seen, for example, in <FIG>, the second end <NUM> of the adjustable panhard bar <NUM> will ordinarily be attached to a suitable bracket arrangement <NUM> (such as the bracket arrangement shown in <CIT> that includes a damping component, however, the bracket arrangement need not include a damping component) on the frame <NUM> via a pin or bolt extending through the bushing <NUM> on the first end of the adjustable panhard bar and through a hole in a flange <NUM> on the bracket arrangement, and the first end <NUM> of the adjustable panhard bar <NUM> will be attached to a suitable bracket arrangement or frame portion <NUM> on the cab <NUM> via a pin or bolt through the bushing <NUM> on the second end of the adjustable panhard bar and through a hole in the bracket arrangement or frame portion on the cab. The adjustable panhard bar <NUM> further ordinarily comprises means, such as jam nuts <NUM>, for locking the linking member <NUM> in position relative to the first bar component <NUM> and the second bar component <NUM>.

As seen, for example, in <FIG> and <FIG>, the front suspension <NUM> can comprise a first bracket arrangement <NUM> on a first (e.g., left) side of the cab <NUM> and a second bracket arrangement <NUM> on a second (e.g., right) side of the cab. The first bracket arrangement <NUM> can be configured to permit pivotal movement of the cab <NUM> relative to the frame <NUM> around an axis A, and the second bracket arrangement <NUM> can be configured to permit movement of the cab along an arc <NUM> of a circle relative to the frame, the circle having its center at the axis A. In this way, as the length of the adjustable panhard bar changes, the cab <NUM> can pivot about the axis A. It will be appreciated that <FIG> and <FIG> exaggerate the typical extent of adjustment that will be provided via the adjustable panhard bar <NUM>. Ordinarily, the panhard bar <NUM> will be adjustable in length only a small amount (e.g., about ½ inch or <NUM>) relative to the size of the frame <NUM> and cab <NUM>, and the angle of the cab centerline CC relative to the frame centerline CF will also ordinarily only be adjustable a small amount, usually less than <NUM> degree. For example, in a presently preferred embodiment, an angular adjustment of about <NUM> degrees of the cab centerline CC relative to the frame centerline CF will result in a lateral shift of about <NUM> of the rear end of the cab <NUM> relative to the frame <NUM>. Of course, if desired, the panhard bar <NUM> can be constructed to permit substantially greater changes in length, and substantially greater angular adjustment.

The second bracket arrangement <NUM> can comprise a first component <NUM> of the second bracket arrangement with a vertically extending elongated hole <NUM> therein. The first component <NUM> of the second bracket arrangement <NUM> will ordinarily be fixed to the frame <NUM> by any suitable means, such as welding, bolts, etc. The second bracket arrangement <NUM> can further comprise a second component <NUM> (shown in phantom) of the second bracket arrangement comprising a pin <NUM> (shown in phantom) fixed to the cab <NUM> by any suitable means (such as welding, bolts, etc.) and disposed in the elongated hole <NUM>. The elongated hole <NUM> can be elongated to permit movement of the cab <NUM> along the arc <NUM> of the circle relative to the frame <NUM> as the length of the adjustable panhard bar <NUM> is changed. The elongated hole <NUM> may be in the shape of an arc.

After the adjustable panhard bar <NUM> is adjusted so that the centerline CC of the cab <NUM> is at a desired angular orientation relative to the centerline CF of the frame, the first and second components <NUM> and <NUM> of the second bracket arrangement <NUM> will ordinarily be locked relative to each other, such as by a bolt on a threaded end of the pin <NUM> that fixes the pin relative to the elongated hole <NUM>.

The first bracket arrangement <NUM> comprises a first component <NUM> of the first bracket arrangement with a vertically extending hole <NUM> therein. The first component <NUM> of the first bracket arrangement <NUM> will ordinarily be fixed to the frame <NUM> by any suitable means, such as welding, bolts, etc. The first bracket arrangement <NUM> can further comprise a second component <NUM> of the first bracket arrangement comprising a pin <NUM> fixed to the cab <NUM> by any suitable means (such as welding, bolts, etc.) and disposed in the hole <NUM>. The hole <NUM> will ordinarily be substantially circular and slightly larger in diameter than the pin <NUM> such that substantially only pivoting movement of the cab <NUM> relative to the frame <NUM> about the axis A centered in the hole <NUM> and pin <NUM> is permitted when the length of the adjustable panhard bar <NUM> is changed. The pin <NUM> will typically include a threaded end so that the first and second bracket components <NUM> and <NUM> can be bolted in place after the adjustable panhard bar <NUM> is adjusted so that the centerline CC of the cab <NUM> is at a desired angular orientation relative to the centerline CF of the frame.

In a method of the invention for attaching a frame <NUM> and an operator cab <NUM> of a truck or tractor vehicle <NUM>, as seen in <FIG> and <FIG>, the frame has a longitudinal centerline CF and the cab has a longitudinal centerline CC. The cab <NUM> is mounted relative to the frame <NUM> via a cab suspension <NUM>, the cab suspension comprising a front suspension <NUM> and a rear suspension <NUM>. The rear suspension <NUM> comprises an adjustable panhard bar <NUM> attached at a first end <NUM> to the cab <NUM> and attached at a second end <NUM> to the frame <NUM>, the adjustable panhard bar being adjustable in length.

The method further comprises adjusting a length of the adjustable panhard bar <NUM> to position the longitudinal centerline CC of the cab <NUM> at a desired angle (usually but not necessarily a zero degree angle) relative to the longitudinal centerline CF of the frame <NUM>. For example, <FIG> shows the centerline CF of the frame <NUM> and the centerline CC of the cab <NUM> (cab shown via solid lines) aligned when the panhard bar <NUM> is at a first length (shown via solid lines) and with the cab (shown via dashed lines) and the centerline of the cab rotated clockwise about the axis A and not aligned with the centerline of the frame when the panhard bar is at a longer second length (shown via dashed lines). Similarly, <FIG> shows the centerline CF of the frame <NUM> and the centerline CC of the cab <NUM> (cab shown via solid lines) aligned when the panhard bar <NUM> is at a first length (shown via solid lines) and with the cab (shown via dashed lines) and the centerline of the cab rotated counter-clockwise about the axis A and not aligned with the centerline of the frame when the panhard bar is at a shorter second length (shown via dashed lines). It will be appreciated that the centerline CF of frame <NUM> and the centerline CC of the cab <NUM> will not necessarily be aligned when the pin <NUM> is in the center of the elongated hole <NUM> as illustrated and that aligning the centerlines may involve adjusting the panhard bar <NUM> to rotate the cab about the axis so that the pin is moved toward one end or the other of the elongated hole.

The adjustable panhard bar <NUM> may be adjusted in length to position the longitudinal centerline CC of the cab <NUM> relative to the longitudinal centerline CF of the frame <NUM> so that wind resistance of the truck or tractor vehicle <NUM> is minimized. Minimizing wind resistance of the truck or tractor vehicle <NUM> will ordinarily be achieved by adjusting the adjustable panhard bar <NUM> in length to align the longitudinal centerline CC of the cab <NUM> relative to the longitudinal centerline CF of the frame <NUM>. The adjustable panhard bar <NUM> may, alternatively or at the same time, be adjusted in length to position the longitudinal centerline CC of the cab <NUM> relative to the longitudinal centerline CF of the frame <NUM> so that fuel economy of the vehicle <NUM> is improved. Ordinarily, fuel economy will be improved as wind resistance is decreased. While it will ordinarily be desirable to align the longitudinal centerline CC of the cab <NUM> and the longitudinal centerline CF of the frame <NUM> to, inter alia, minimize wind resistance and improve fuel economy, there may be situations where it is desired to misalign the centerlines, and this is also possible via the present invention.

The truck or tractor vehicle and method according to the present invention facilitates correcting the positioning of a cab relative to a frame during manufacturing or after use. Because the correction can be accomplished via only a few bolt loosenings and tightenings, it can be achieved in a simple and inexpensive manner.

In the present application, the use of terms such as "including" is open-ended and is intended to have the same meaning as terms such as "comprising" and not preclude the presence of other structure, material, or acts. Similarly, though the use of terms such as "can" or "may" is intended to be open-ended and to reflect that structure, material, or acts are not necessary, the failure to use such terms is not intended to reflect that structure, material, or acts are essential. To the extent that structure, material, or acts are presently considered to be essential, they are identified as such.

Claim 1:
A truck or tractor vehicle (<NUM>), comprising:
a frame (<NUM>) having a longitudinal centerline;
an operator cab (<NUM>) mounted relative to the frame via a cab suspension (<NUM>), the cab having a longitudinal centerline;
the cab suspension comprising a front suspension (<NUM>) and a rear suspension (<NUM>), the rear suspension comprising an adjustable panhard bar (<NUM>) attached at a first end (<NUM>) to the cab and attached at a second end (<NUM>) to the frame, the adjustable panhard bar being adjustable in length to position the longitudinal centerline of the cab at a desired angle relative to the longitudinal centerline of the frame.