Truck suspension used as a crane counterweight

A boom truck includes a truck chassis having a frame, a boom assembly connected to the frame, and a boom counter weight assembly rotatably connected to the boom assembly. The boom counter weight assembly is configured to be disposed between a first position to extend a wheel base of the boom truck and a second position to define a counterweight relative to the boom assembly.

BACKGROUND

Conventional boom trucks typically include a telescoping or extendable arm mounted to the truck frame. For example, front mounted boom trucks typically include a boom assembly mounted to the truck frame at a location near the cab of the boom truck. In another example, rear mounted boom trucks typically include a boom assembly mounted to the to the truck frame at a location near the rear axle of the truck. In either case, these boom trucks typically do not include a counterweight and instead rely on the weight of the vehicle to counterbalance a load carried by the boom during operation.

SUMMARY

The U.S. Federal Bridge Formula was established to limit the weight-to-length ratio of vehicles in order to minimize the wear-and-tear experienced by bridges in the U.S. highway system. Under present regulations, two or more consecutive axles of a vehicle may not exceed the weight computed by the Bridge Formula even though single axles, tandem axles, and gross vehicle weights are within legal limits. For example, for a vehicle having a gross vehicle weight of 80,000 pounds, the Federal Bridge Formula requires a minimum distance of thirty-four feet, six inches between a centerline of a front tandem and a centerline of a rear tandem.

Conventional boom trucks typically do not meet the requirements of the U.S. Federal Bridge Formula. For example, conventional boom trucks in the weight range of 48,000 to 58,000 pounds typically have a consecutive axle wheel base of twenty-six feet, on average. Further, conventional boom trucks in the weight range of between about 48,000 and 84,000 pounds typically have a consecutive axle wheel base of thirty-one feet, on average. In these examples, a permit is required to drive the boom trucks on the road ways in the U.S.

Further, the permits are typically only issued for boom trucks having an irreducible load. Under these requirements, in order to be compliant with the permit, the boom truck operator cannot add a counterweight to the boom in order to counterbalance the boom during operation. This limits the amount of load that the boom can lift during operation.

By contrast to conventional boom trucks, embodiments of the present innovation relate to a boom truck having a boom counterweight assembly. In one arrangement, the boom counter weight assembly includes a frame connected to a wheel base assembly where the wheel base assembly includes a set of wheels connected to a base by an axle. The boom counter weight assembly increases weight-to-length ratio of a corresponding boom truck when driven. For conventional boom trucks in the weight range of between about 48,000 and 84,000, this allows the boom trucks to be compliant with U.S. Federal Bridge Formula and limits need for special permits. Also, the boom counterweight assembly can operate as a counterweight to the boom during operation. Because the boom counterweight assembly merely pivots relative to the boom and is not added or removed before and after operation, the boom counterweight assembly maintains the requirements of the boom truck having an irreducible load.

In one arrangement, a boom truck, comprises a truck chassis having a frame, a boom assembly connected to the frame, and a boom counter weight assembly rotatably connected to the boom assembly. The boom counter weight assembly is configured to be disposed between a first position to extend a wheel base of the boom truck and a second position to define a counterweight relative to the boom assembly.

DETAILED DESCRIPTION

Embodiments of the present innovation relate to a boom truck having a boom counterweight assembly. In one arrangement, the boom counter weight assembly includes a frame connected to a wheel base assembly where the wheel base assembly includes a set of wheels connected to a base by an axle. The boom counter weight assembly increases weight-to-length ratio of a corresponding boom truck when driven. For conventional boom trucks in the weight range of between about 48,000 and 84,000, this allows the boom trucks to be compliant with U.S. Federal Bridge Formula and limits need for special permits. Also, the boom counterweight assembly can operate as a counterweight to the boom during operation. Because the boom counterweight assembly merely pivots relative to the boom and is not added or removed before and after operation, the boom counterweight assembly maintains the requirements of the boom truck having an irreducible load.

FIG. 1illustrates a boom truck10, according to one arrangement. As illustrated, the boom truck10includes a truck chassis12which includes a frame16, a boom assembly18mounted to the frame16and a capacity enhancing device, termed a boom counter weight assembly20. In one arrangement, the frame16can be manufactured from 80,000 P.S.I. steel, 110,000 P.S.I. steel, or, in certain cases, 130,000 P.S.I. steel. In one arrangement, the boom truck10includes an air ride suspension on the two rear drive axles.

The boom assembly18includes a boom22and a boom control24rotatably coupled to the frame16. The boom control24is configured to allow a user to operate the boom22. For example, the boom control24includes a housing25containing a set of controls (not shown) that allow the operator to rotate the boom control24about a longitudinal axis26relative to the frame16and to rotate the boom22about a lateral axis28relative to the housing25.

In the example illustrated, the boom counter weight assembly20includes a frame30connected to a wheel base assembly32. While the frame30can be configured in a variety of ways, in one arrangement, the frame30includes a set of metallic bars, such as steel bars, that defines a substantially hollow structure.

The frame30is rotatably connected to the housing25, via a connection35, such as a pin connection. In one arrangement, the boom assembly18includes a hydraulic cylinder assembly36connected between the frame16and the frame30of the boom counter weight assembly20. As will be described below, the hydraulic cylinder assembly36is configured to rotate the boom counter weight assembly20between a first position, as shown inFIG. 1, and a second, counterweight position, as shown inFIGS. 2-4. The location of the connection of the hydraulic cylinder assembly36relative to the frame30can vary depending on the load capacity of the hydraulic cylinder assembly36.

In one arrangement, a hydraulic cylinder of the hydraulic cylinder assembly36includes a holding valve configured to hold pressure in case of a hydraulic hose failure. In one arrangement, the hydraulic cylinder assembly36includes a travel limiting device to limit the rotation of the boom counter weight assembly20to the second position to limit damage when lifted into a crane operating position. In one arrangement, the frame that the hydraulic cylinder is attached to is configured with adequate capacity to safely lift the flip axle from a travel to crane operating position.

In the arrangement shown, the wheel base assembly32includes a set of wheels40connected to a base43by an axle (not shown). The base43is connected to the frame16via a removable pin connection. In one arrangement, the wheel base assembly32is configured as a flip axle. In one arrangement, the flip axle is manufactured from the same strength steel as the frame16(e.g., 80,000 P.S.I. steel, 110,000 P.S.I. steel, or, 130,000 P.S.I. steel). With a flip axle configuration, the wheel base assembly32includes a braking mechanism for the wheels but is not powered by a drive shaft of the boom truck10. In one arrangement, the brakes of the flip axle can receive air for operation via an airline38.

In one arrangement, a frame of the flip axle can run parallel with the truck frame16and two or three cross members (i.e., depending on crane capacity) can be installed on the frame of the flip axle at a 90° angle relative to the truck frame16. Depending on the truck manufacturer, the cross members can be assembled with HUCKBOLTS™, similar to those used in a cross member above the truck's transmission, to minimize loosening during use. In one arrangement, the flip axle includes an air ride suspension, as opposed to a leaf spring suspension, as well as both an automatic and manual air pressure limiting control. In one arrangement, the flip axle can be disposed in a variety of operating positions, such as between 3 and 5 operating positions. Each position can include have a proximity switch which is coordinated by the truck's lifting computer or L.M.I. In one arrangement, the weight of the frame and flip axle will vary, according to the lifting capacity of the crane.

During operation, the boom counter weight assembly20is configured to rotate between a first position, as illustrated inFIG. 1, to a second position, as illustrated inFIGS. 2 and 3, relative to the boom control24to act as a counterweight to the boom assembly18.

In the first position as illustrated inFIG. 1, the wheel base assembly32of the boom counter weight assembly20is connected to the frame16, via a connection42such as a pin. When disposed in the first position, the boom truck10can be driven from location to location without requiring a travel permit. For example, the length44of the wheel base of the truck chassis12is about 26 feet while the length46of the wheel base between a tag axle14and the wheel base assembly32is between about 10 feet and 15 feet, depending upon capacity. In total, the boom truck10is configured with a wheel base of between about 36 feet and 51 feet.

As provided above, the boom counter weight assembly20is configured to rotate relative to the boom control24to act as a counterweight to the boom assembly18. In one arrangement, in a second position as illustrated inFIG. 1, the boom counter weight assembly20is disposed relative to the boom22such that a longitudinal axis50of the boom counter weight assembly20is substantially aligned with a longitudinal axis52of the boom22. For example, in the second position the length56of the moment arm formed by the boom counter weight assembly20from a vertical axis27of the boom control24to an outer portion of the wheel40is between about 10 feet and 15 feet. Such positioning is termed full tail swing mode. For a boom truck10having a capacity between about 30,000 pounds and 120,000 pounds (between about 15 and 60 tons) a tag axle weight of the boom truck10(i.e., the weight of the non-powered rearmost axle as disposed behind the drive axles) is between about 7,000 pounds and 16,000 pounds.

During operation, for example, the operator disengages the boom counter weight assembly20from the frame16via connector42. The operator actuates the hydraulic cylinder assembly36to rotate the boom counter weight assembly20about connection35. With the boom counter weight assembly20positioned in full tail swing mode (i.e., such that the longitudinal axis50of the boom counter weight assembly20is substantially aligned with the longitudinal axis52of the boom22), the boom counter weight assembly20is configured as a counterweight to the boom22during operation. The counterweight allows the boom operator to extend the boom22at a distance from the boom control24and increases amount of load that the boom22can lift during operation, compared to conventional boom trucks.

Use of the boom counter weight assembly20allows the use of a counterweight with the boom truck10. Additionally, the boom counter weight assembly20provides a number of benefits to the boom truck10. For example, as provided above, when disposed in the first position, the boom counter weight assembly20extends the length of the wheel base of the boom truck10. Therefore, in the case where the boom truck10has a weight of between about 48,000 pounds and 84,000 pounds, the total length of the wheel base for the boom truck10(i.e., a length between about between about 36 feet and 46 feet). Accordingly, a boom truck10having a boom counter weight assembly20meets the U.S. Federal Bridge Formula without requiring a particular travel permit.

In another example, because the boom counter weight assembly20is connected to the boom control24in a substantially secure manner, the boom truck10meets the requirements of having an irreducible load. In the event that the boom truck10required a permit under the U.S. Federal Bridge Formula, because the boom truck10includes an irreducible load, the boom truck10can be considered compliant with the permit.

As provided above, the boom counter weight assembly20can be positioned in full tail swing mode, shown inFIG. 2. However, the boom counter weight assembly20can be disposed in a variety of positions relative to the boom control24.

For example, as illustrated inFIG. 3, the boom counter weight assembly20can be disposed such that the longitudinal axis26of the boom counter weight assembly20defines an acute angle70relative to a vertical reference72where the vertical reference72is substantially parallel to the vertical axis27of the boom control24. With such positioning, termed zero tail swing mode, a distance74between the vertical axis27and the outer edge of the wheels40is less than the distance56illustrated inFIG. 2. Therefore, in this position, the boom counter weight assembly20can act as a counter weight with a relatively reduced moment arm within a relatively narrow space. As such, the boom counter weight assembly20can be utilized in cases where space is an issue.

As described above, during operation, an operator disengages the boom counter weight assembly20from the frame16via connector42and actuates the hydraulic cylinder assembly36to rotate the boom counter weight assembly20(i.e., the frame30and wheel base assembly32) about connection35. Such description is by way of example only. In one arrangement, with reference toFIG. 4, the frame30is configured to be disengaged from the base43and rotated about connection35via the hydraulic cylinder assembly36.

As provided above, certain dimensions were used for different aspects of the boom truck. For example, as described with reference toFIG. 2, in the second position the length56of the moment arm formed by the boom counter weight assembly20from a vertical axis27of the boom control24to an outer portion of the wheel40is between about 10 feet and 15 feet. Further, with reference toFIG. 3, in zero tail swing mode, a distance74between the vertical axis27and the outer edge of the wheels40is less than the distance56illustrated inFIG. 2. These, and other, dimensions described above are provided by way of example only. It is understood that all dimensions are variable and approximate, according to different capacities associated with the particular boom truck.

While various embodiments of the innovation have been particularly shown and described, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the innovation as defined by the appended claims.