Land vehicles – Wheeled – Articulated vehicle
Reexamination Certificate
1999-07-20
2001-05-15
Johnson, Brian L. (Department: 3618)
Land vehicles
Wheeled
Articulated vehicle
C280S407100, C280S423100, C280S430000, C280S433000, C280S438100, C280S441000, C280S656000
Reexamination Certificate
active
06231064
ABSTRACT:
FIELD OF THE INVENTION
This invention is concerned with new automotive transport tractors and semi-trailers, and the combination thereof, and particularly to such combinations wherein the tractor and semi-trailer can be rigidly connected together to facilitate the connection thereto of a second semi-trailer or trailer to provide a double trailer combination.
REVIEW OF THE PRIOR ART
Increasing the load-carrying capacity of an automotive transport unit (i.e. a unit employing only a single tractor in combination with one or more semi-trailers and/or trailers) is of continuing commercial interest, owing to the cost savings that are possible, and accordingly there have been a substantial number of prior proposals disclosing different equipment for this purpose. Operators interested in maximizing load-carrying capacity usually wish to employ a semi-trailer unit that is as long as possible, but almost all jurisdictions have regulations as to the maximum length of a single tractor/semitrailer combination that is allowed on the highways, typically about 18 meters (60 feet). Another practical limitation on maximum length is imposed by the need when turning corners for the rear wheels of the unit to “off-track” within minimum and maximum limits. A solution that is used increasingly where permitted is to split the load-carrying unit into a semi-trailer pivotally connected to the tractor by the usual king-pin and fifth wheel combination, and a trailer pivotally connected in some way to the rear end of the semi-trailer. Single tractor/semi-trailer combinations are already somewhat unstable, especially with slippery road conditions, owing to the presence of the single articulating pivot and the yaw that it permits, but the occasional jackknifing and overturning that occurs is accepted because of the inherent overall flexibility, practicability, and economy of operation of such units. The problem of yaw instability and the possibility of jackknifing and overturning is considerably increased with double units owing to the presence of at least two articulating pivot points spaced longitudinally a relatively long distance apart, resulting in a considerable increase in the overall yaw rate of the unit. There is therefore a need in the industry for new automotive transport units providing such increased load carrying capacity without, if possible, increasing the yaw rate thereof beyond an acceptable value and also, if possible, owing to the necessarily inherent conservatism of the industry toward radically new designs, making use of established designs of tractors, trailers and semi-trailers for their implementation.
DEFINITION OF THE INVENTION
It is therefore the principal object of the invention to provide a new tractor unit and a new semi-trailer unit that can be used in combination with one another to form a readily releasable rigidly coupled tractor/semi-trailer combination.
It is a more specific object to provide such a tractor/semi-trailer combination comprising a stable rigid releasable connection between the two components that permits maintenance of the required weight distribution between the two components, minimizes roll instability, and eliminates jackknifing.
It is a further object to provide such a tractor/semi-trailer combination comprising a stable rigid releasable connection between the two components making it particularly suited for the coupling of a second semi-trailer unit thereto with only a single articulating pivot present in the resulting double trailer combination, thereby minimizing roll instability and reducing the possibility of jackknifing as compared to the existing double trailer units.
In accordance with the present invention there is provided a new automotive tractor unit for use in a rigidly-coupled tractor/semi-trailer combination comprising:
a long wheel base tractor with a tractor chassis having front and rear ends, a steering wheel assembly and driver's cab at the front end and a drive wheel assembly at the rear end;
the tractor when in the combination being employed with an associated semi-trailer that has front and rear ends and has a king pin at its front end and at least one pair of running wheels at its rear end;
means mounting a fifth wheel assembly on the tractor chassis for extended longitudinal movement between a semi-trailer receiving position close to the rear end of the tractor chassis and a semi-trailer mounting position close to the rear of the driver's cab;
said extended longitudinal movement being such that in the semi-trailer receiving position the fifth wheel assembly can be coupled with and released from the semi-trailer king pin, and in the semi-trailer mounting position the semi-trailer is mounted on the tractor chassis with the fifth wheel assembly and the king pin coupled together and with the running wheels of the semi-trailer adjacent to the tractor drive wheel assembly; and
the tractor chassis having thereon connecting means for cooperation with connecting means on the associated semi-trailer chassis when the semi-trailer is mounted on the tractor chassis, the connecting means permitting pitching between the tractor chassis and the semi-trailer chassis while preventing yaw between them.
Also in accordance with the invention there is provided a new semi-trailer unit for use in a rigidly-coupled tractor/semi-trailer combination comprising;
a semi-trailer chassis having front and rear ends, a king pin at its front end for connection to a fifth wheel assembly of an associated tractor unit, and at least one pair of running wheels at its rear end;
the semi-trailer when in the combination being employed with an associated tractor with a tractor chassis having front and rear ends, a steering wheel assembly and driver's cab at the front end and a drive wheel assembly at the rear end, and also when in such combination being mounted on the tractor chassis with its front end close to the rear of the driver's cab and its running wheels adjacent to the tractor drive wheel assembly;
connecting means on the semi-trailer chassis for cooperation with associated connecting means on the tractor chassis when the semi-trailer is mounted on the tractor, the connecting means permitting pitching between the tractor chassis and the semi-trailer chassis while preventing yaw between them; and
a retractable landing gear mounted beneath the semi-trailer chassis and movable thereon between a forward position in which it is closer to the king pin and is adapted to support the front end of the semi-trailer in the absence of the tractor, and a rear position in which it is further from the king pin and adjacent to its running wheels and permits the semi-trailer to be mounted on the tractor chassis with its front end close to the rear of the driver's cab and its running wheels adjacent to the tractor drive wheel assembly.
Also in accordance with the invention there is provided a new automotive tractor/semi-trailer combination comprising a new automotive tractor unit as specified above in combination with a new semi-trailer unit as specified above.
Further in accordance with the invention there is provided a combination as specified in the immediately preceding paragraph in combination with a second semi-trailer coupled to the rear of the first mentioned semi-trailer, either by a king pin on the second semi-trailer engaging with a fifth wheel assembly at the rear of the first semi-trailer or by a king pin on the second semi-trailer engaging with a fifth wheel assembly on a dolly coupled to the rear of the first semi-trailer.
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patent: 4033625 (1977-07-01), Fikse
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Draper Deanna
Johnson Brian L.
Rogers Stanley J.
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