Patent ID: 12246783

DETAILED DESCRIPTION OF THE INVENTION

FIG.1illustrates the left side of a tractor20pulling a trailer22having a spread axle assembly24and carrying a load26(shown schematically as a box) on a surface28(such as a road or ground if off road). The right side is substantially similar to the left side. Tractor20may be any kind of tractor include ones suitable for on-road use and ones for off-road use (not including railroads). Typically, tractor20has a steering axle30attached to two steering wheels32including tires33and one or more drive axles34, each attached to four drive wheels36including tires37, and a suitable trailer hitch38for attaching tractor20and trailer22together.

With reference toFIGS.1and2, trailer22may be any suitable trailer including a lowboy trailer or an open deck or platform trailer. As illustrated in the figures, trailer22is a lowboy trailer which is frequently used for hauling large and heavy equipment particularly construction and mining equipment. At its front end39, trailer22has a gooseneck40having a hitch coupler such as a kingpin for coupling with trailer hitch38. Gooseneck40may be removable allowing a load26to drive onto trailer22(and trailer deck42). Typically, there can also be conventional electrical, air or hydraulic connections, wires or hoses (not shown) between the tractor20and trailer22for operating the brakes, brake lights, etc. and extending to spread axle assembly24. Trailer22has a support surface or trailer deck42supporting load26and one or more trailer axles44, typically two or three axles44, attached to trailer wheels46including tires47. The last of axles44, or rear trailer axle, is denoted by reference numeral44r.

With particular reference toFIGS.1,2,5and8, trailer22has a trailer frame48extending over axles44and through gooseneck40and includes two or more parallel beams50. The hitch coupler is attached, preferably mounted, to frame48. Beams50are of the box type, preferably having 4 closed sides for most of their length. Inside each beam50is a beam52, which can also be of the box type, which can be slid in and out of beam50. The combination of one beam50and one beam52may be considered to constitute a single telescopic beam that can telescope in and out. Beams52are shown extended out inFIGS.1,2, and5-8and retracted inFIGS.3and4. Beams52have spaced apertures54which in conjunction with a latch mechanism56locks the extension of beams52relative to beams50. Latch mechanism56is attached to frame48and can be a conventional air-operated deadbolt latch having a bolt56athat closely fits apertures54and can be withdrawn or inserted into an aperture54. A switch57may be used to operate the bolt. Preferably, there are two latch mechanisms56, one for each beam52. The bolt can be secured in the locked position by a clevis pin. Preferably, the bolt extends through both beam50and beam52. Latch mechanism56could also be a solenoid, a manually operated or hydraulically operated deadbolt latch.

As shown inFIGS.5and8, there is a hose support58inserted into one of apertures54. Additional hose supports58may be used as necessary. As shown inFIG.12, hose support58has a loop60through which conventional air and hydraulic hoses and electrical wires (not shown) can be run so that such hoses and wires can extend from rear axle44rto spread axle assembly24. Hose support58is held in place in an aperture54by loop60on one side and by a pin62on the other side. Removal of pin62allows hose supports to be removed and placed in appropriate apertures54depending on the degree of extension or retraction of beams52.

To facilitate the telescoping of beams50and52, preferably two slide wheels are provided. As can be best seen inFIGS.5and11, located close to each outlet63of beam50, where beam52enters beam50, is a slide wheel64which is in contact with a top surface65of beam52. As can be best seen inFIG.13, at the end69of beam52is a slide wheel66. Slide wheel66is located inside beam50. It contacts an inner bottom surface67of beam50.

Behind rear axle44ris a rear bumper68in case spread axle assembly24is disconnected from trailer22.

Turning now to spread axle assembly24, which is shown in greater detail inFIGS.3-10, beams52are attached to a front portion70of spread axle assembly24. Front portion70has a cross bar72, which are attached to beams52. Spread axle assembly24also has one or more upper hinges74and one more lower hinges76, a rear portion78, and a hydraulic cylinder80. Hinges74and76connect front portion70and rear portion78together and permit rear portion78to pivot vertically relative to front portion70. Hinges74and76have pivot axes75and77, respectively, that are substantially perpendicular to a longitudinal direction104of trailer22. Preferably there are two upper hinges74, each having removable upper pivots or hinge pins82, which are substantially horizontally aligned. Preferably there are two lower hinges76, each having removable lower pivots or hinge pins84, which are substantially horizontally aligned.

Hydraulic cylinder80is pivotally attached to cross bar72and pivotally attached to rear portion78. Hydraulic cylinder80is of conventional construction and has conventional parts including a piston and a piston rod85. Piston rod85is shown connected to rear portion78, but the cylinder could be reversed such that piston rod85is attached to cross bar72. Hydraulic cylinder80is in an extended state as shown inFIG.4and in a compact state inFIG.3. Piston rod85is attached to rear portion78by a clevis122and a pin124. Clevis122has two positions (a close position126aand a distal position126b) for pin124. Each position126is formed by a pair of opposed apertures in clevis122.

Rear portion78has a triangular frame86, a rear frame88, and one or more axles90. Rear frame88is pivotally attached to triangular frame86by pivot92, which is substantially vertically aligned when trailer22is on level ground, allowing axle90to turn left or right relative to triangular frame86and front portion70. Rear frame88has a central triangular frame portion93. Axle90is attached to rear frame88by a suspension94. Suspension94may be a spring suspension, an air-ride suspension, a hydraulic suspension or a combination. As shown, suspension94is an air-ride suspension having air bags95. The hydraulic system for spread axle assembly24(and suspension94) includes hydraulic accumulator96, hydraulic cylinder80, and related conventional hydraulic hoses, tubing, etc. (not shown). InFIGS.8-10, axle90has been omitted for clarity, but cradles98, which are part of suspension94, for axle90are shown. Conventionally, trailer22or tractor20has a hydraulic power pack (not shown) which can be used for operating hydraulic cylinder80and charging suspension94. The hydraulic system of spread axle assembly24also has a hydraulic lock valve99(shown schematically) for isolating the hydraulic system of spread axle assembly24from the hydraulic system of the rest of trailer22.

At the very back of spread axle assembly24is located a rear light bar100.

Rear portion78has a latch mechanism102for locking axle90in a position substantially perpendicular to longitudinal direction104(substantially horizontal and in the plane of the paper inFIG.1) of trailer22. Latch mechanism102is located proximal to the tip of central triangular frame portion93. Latch mechanism102includes a deadbolt106which can extend through and closely fits an aperture108in triangular frame86and an aperture110in rear frame88. Deadbolt106may be air-operated using air switch111(shown schematically), hydraulically operated, manually operated or electrically-operated such as a solenoid.

Spread axle assembly24also has one or more stands112(two shown) which are pivotally attached to one of front portion70and rear portion78and removably attached to the other by a clevis pin114or similar. Axle (or axles90) have wheels116(typically four per axle) having tires118.

In operating trailer22, the operator, without any assistance, will be able to easily change spread axle assembly24from a storage position shown inFIG.3, to a close coupled position (seeFIG.4), to a spread or extended position (seeFIG.5), and to positions between the close coupled position and the spread or extended position. Additionally, after the appropriate non-storage position is selected the spread axle assembly may be operated in selected to a hydraulic booster configuration to carry a portion of load26and allowing pivoting up and down due to surface unevenness as shown inFIGS.6and7.

When it is desired to move to booster from the stored position (seeFIG.1), a conventional hydraulic power pack (not shown) on trailer22or tractor20is started. Stands112are un-pinned, i.e., clevis pin114is removed from stands112. The hydraulic controls of the power pack are used to extend out piston rod85causing rear portion78to pivot around upper pivots82and to lower to the ground. Once piston rod85is fully extended and tires118on surface28, lower hinge pins84are installed in lower hinges76. The trailer hydraulic power pack can then be shut off. Spread axle assembly24is in the close coupled position (seeFIG.4).

If it is desired to move spread axle assembly24to a spread or extended position, the brakes are set on axle90/wheels116. The bolts of latch mechanisms56are released from apertures54with switch57after removing the clevis pin. Tractor20is slowly moved forward towing trailer22forward and extending beams52(or telescoping the telescopic beams out) until they are close to the desired position. Switch57is activated. The tractor and trailer are slowly moved until the bolts of latch mechanisms56engage the appropriate apertures54. Apertures54are located advantageously along beams52to achieve, for example, a distance120of 13.1 and 14.1 feet between rear axle44rand axle90. Shorter distances are also advantageous for reducing the overall length of trailer22such as 12′1″, 11′1″, 10′1″, 9′2″ and a close position. Optionally, hose supports58can be inserted into apertures54and hoses and wires supported by hose supports58.

Before spread axle assembly24is used, it is preferable to allow pivoting around pivot92to eliminate or reduce skidding of tires118around corners. To do so, deadbolt106is disengaged from at least one of aperture108and aperture110using air switch111. The trailer can now be operated with spread axle assembly24as a fixed booster.

If it is desired to operate the spread axle assembly24as a hydraulic booster, the hydraulic power pack is started and pin124is removed from distal position126b. Using the hydraulic controls of the hydraulic power pack, piston rod85is moved inwardly and pin124is inserted into close position126athereby reattaching piston rod85to rear portion78. Next, upper pivots or hinge pins82are removed. Using the hydraulic controls, hydraulic accumulator96is charged pushing axle90downwardly relative to rear frame88thereby shifting an increasing amount of the weight of load26to axle90until the desired loading on axle90is achieved. Once the desired loading has been reached, hydraulic lock valve99is closed to prevent pressure loss. Spread axle assembly24can now be operated as a hydraulic booster. Hydraulic cylinder80, which remains in hydraulic communication with hydraulic accumulator96, gives axle90increased travel to keep axle loadings consistent over uneven roads (seeFIGS.6and7). It is possible to achieve an additional 18″ of total travel up and down in the booster configuration.

If it is desired to return spread axle assembly24from its hydraulic booster configuration to the stored position (seeFIG.1), hydraulic lock valve99is opened. The hydraulic pressure in hydraulic accumulator96is relieved using the hydraulic controls. The hydraulic power pack is started and upper hinge pins82are installed in upper hinges74. Deadbolt106is engaged with both aperture108and aperture110using air switch111to prevent pivoting around pivot92, which could be dangerous during transport.

The connection of piston rod85to clevis122is adjusted. First, pin124is removed. Next, using the hydraulic controls, piston rod85is moved outwardly and piston rod is reattached to clevis122by inserting pin124into distal position126b. The brakes are set on spread axle assembly24. The bolts of latch mechanisms56are released from apertures54with switch57. Trailer22is towed by tractor20backwards, telescoping the telescopic beams in until the spread axle assembly gently hits the rear of trailer stops. Switch57is activated, engaging latch mechanisms56thereby locking beams52in the closed position. Next lower hinge pins84are removed. Using the hydraulic controls, piston rod85is retracted pulling rear portion78toward front portion70causing rear portion78to rise. Stands112are pinned to using clevis pins114. The hydraulic power pack is shut off. The trailer can now be operated with the booster in the stored position (seeFIG.3).

As can be seen, the invention overcomes deficiencies discussed in the background. Additionally, hydraulic cylinder80is advantageously used to improve the suspension of the spread axle assembly.

Definitions: As used in this application, substantially vertical and substantially horizontal directions mean that when trailer22is on horizontal and level surface28, e.g., the ground, that the directions are vertical and horizontal, respectively, subject to manufacturing tolerances and normal wear and tear including uneven tire wear. In any case, substantially vertical and substantially horizontal should not deviate more than 5 degrees from vertical or horizontal, respectively. Similarly, substantially perpendicular or substantially parallel reflect manufacturing tolerances and normal wear and tear, but should not deviate more than 5 degrees from perpendicular or parallel, respectively.

While the invention has been described with respect to certain embodiments, as will be appreciated by those skilled in the art, it is to be understood that the invention is capable of numerous changes, modifications and rearrangements, and such changes, modifications and rearrangements are intended to be covered by the following claims.