Bridges – Transportable
Patent
1997-03-28
1999-01-26
Graysay, Tamara L.
Bridges
Transportable
14 25, E01D 1512, E01D 1510
Patent
active
058625569
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to a bridging span structure intended in particular for the crossing of ditches by vehicles such as armoured vehicles of the Engineer Corps.
The document FR-B-2,683,837 in the name of the applicant describes a bridging span structure disposed on a transport vehicle so as to be laid down alone or in association with an identical bridging span structure over a ditch by a suitable lay-down system mounted onto the transport vehicle.
SUMMARY OF THE INVENTION
The present invention has the purpose of improving the bridging span structure described in the hereabove document by providing a bridging span structure permitting the forces applied thereon or on an end-to-end assembly of bridging span structures during the launching phase of the bridging span structure or of the assembled bridging span structures above the ditch to be crossed or during the passage of vehicles upon the bridging span structure or the assembled bridging span structures disposed over across the ditch to be better sustained.
For that purpose, the invention proposes a bridging span structure intended in particular to the crossing of ditches by vehicles such as armoured vehicles of the Engineer Corps formed of at least one bridging span element comprising a rigid central box with an upper treadway and two access jibs assembled to both ends of the central box so as to extend the trackway of the central box, at least one of the access jibs being fastened to the central box on the one hand by a transverse pivot pin and on the other hand by unlockable locking means allowing the access jib to assume a lower position bearing upon one edge of a ditch or an upper or raised position for being coupled to an access jib of another bridging span element. The locking means comprise at least two elements forming parallel tie-rods disposed symmetrically to the longitudinal axis of the bridging span element and pivotally connected to the access jib by two stationary transverse pins, and two transverse locking shafts with a controlled displacement permitting the fastening of both tie-rod elements to the central box in two different positions corresponding to the lower and raised positions, respectively, of the access jib.
Preferably the pivot pin of the liftable access jib is located at the lower portion thereof and the locking means of this jib are located at the upper portion of the jib and of the central box.
The transverse locking shafts are movably mounted into two bores of the central box and may be each inserted into one of two bores of the corresponding tie-rod element defining both lower and raised positions of the access jib.
Preferably the means for the control of the displacement of both transverse locking shafts comprise a transverse shaft rotatably mounted into a casing made fast to the central box, two threaded rods made fast to both ends of the rotary shaft coaxially therewith and onto each one of which is assembled an internally tapped sleeve constituting a transverse locking shaft, and a drive means for rotating the rotary shaft so as to displace in translation in opposite directions both sleeves from one unlocking position to a locking position of the tie-rod elements.
The drive means for rotating the rotary shaft comprises a drive rod extending through the central box and one end portion of which is mounted for rotation in the supporting casing of the rotary shaft and carries a bevel gear meshing with another bevel gear made fast to the rotary shaft, the other end of the drive rod being mechanically coupled to a sprocket pinion mounted for rotation onto the central box on one side thereof and operatively rotated by a transmission chain.
The other end of the drive rod is coupled to the rotary shaft of the side sprocket pinion by a Cardan joint.
The locking shaft of a corresponding tie-rod element extends through the bore defining the lifted position of the access jib with a clearance permitting to bring into abutment the bearing front faces of the access jib and of the central box d
REFERENCES:
patent: 3713599 (1973-01-01), Smith et al.
patent: 4393533 (1983-07-01), Terrien et al.
patent: 4411037 (1983-10-01), Terrien et al.
Constructions Industrielles de la Mediterranee - CNIM
Graysay Tamara L.
Singh Sunil
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