Liftgate having a side-loadable load platform

A liftgate for loading and unloading cargo from a vehicle. The liftgate includes a moveable load platform having a proximal deck section and a distal deck section pivotally coupled to the proximal deck section. A side ramp is pivotally coupled to the distal deck section to facilitate unobstructed side loading and unloading of the distal deck section of the load platform.

BACKGROUND

The present disclosure is directed to a liftgate having a load platform that is selectively moveable between a lowered position and a raised position, and a side ramp pivotally coupled to a side of the load platform such that cargo can be loaded onto or unloaded from the side of the load platform via the side ramp. In particular, the liftgate includes a restraint mechanism coupled to the load platform for supporting the load platform while not interfering with cargo movement between the load platform and the side ramp.

Liftgates are used in connection with vehicles such as trucks and trailers to facilitate the loading and unloading of cargo from the vehicle when the cargo needs to be moved vertically between a loading surface, such as a ground surface or a dock surface, and the surface of the vehicle cargo floor. The liftgate is typically mounted to the rear end of a truck or trailer to facilitate loading and unloading of the truck or trailer. Typically, cargo is moved on or off of the load platform over the distal end of the load platform in a direction parallel to the longitudinal axis of the vehicle and the load platform. This requires that the vehicle and the load surface be located in an end-to-end relationship. Often times, the vehicle must be positioned alongside the loading surface such that cargo cannot be directly moved between the load surface and the distal end of the load platform, such that side loading of the load platform in a direction transverse to the longitudinal axis of the load platform and vehicle is desirable.

SUMMARY

A liftgate for use in loading and unloading cargo from a vehicle. The liftgate comprises a lift mechanism and a moveable load platform having a proximal end coupled to the lift mechanism, a distal end spaced apart from the proximal end, a first side edge extending between the proximal end and the distal end of the load platform, and a second side edge extending between the proximal end and the distal end of the load platform. The load platform is selectively moveable between a lowered position and a raised position by the lift mechanism. A restraint is coupled to the first side edge of the load platform and is adapted to support the load platform. A side ramp is pivotally coupled to the first side edge of the load platform between the restraint and the distal end of the load platform. The side ramp is selectively pivotal with respect to the load platform between an operational position wherein the side ramp extends outwardly from the load platform and a stored position. When the side ramp is in the operational position, cargo can be moved along an unobstructed pathway between the side ramp and the load platform without interference by the restraint thereby enabling side loading and unloading of the load platform.

DETAILED DESCRIPTION

The present disclosure is directed to a liftgate for a vehicle having a load platform that is selectively moveable between a lowered position and a raised position and a side ramp coupled to a side of the load platform for side loading and unloading of cargo onto or from the load platform by way of the side ramp. An embodiment of the liftgate having a side-loadable load platform is shown inFIGS. 1-16as liftgate20. Liftgate20is adapted to be mounted to the aft end of a vehicle22. Vehicle22may comprise a truck, trailer, or other cargo conveying apparatus. Vehicle22includes a generally planar and horizontal cargo floor24having a generally linear rear edge26. Vehicle22may include wheels28rotatably mounted to vehicle22for rotation about one or more rotational axes30. Rear edge26of cargo floor24and rotational axes30of wheels28are generally parallel to one another. Vehicle22includes a transverse axis that is generally parallel to rear edge26of cargo floor24and rotational axes30of wheels28, and a longitudinal axis that extends from the aft end to the front end of vehicle22generally perpendicular to rear edge26of cargo floor24and rotational axes30of wheels28. The surface of cargo floor24of vehicle22is typically located at a vertical height above a loading surface. The loading surface may comprise the surface of the ground, road, parking lot or the like on which wheels28of vehicle22are supported, or the surface of a loading dock, side walk or the like which may be located at a vertical height above the surface on which the wheels28are supported.

Liftgate20includes a lift mechanism36. Lift mechanism36includes columns38A and38B that are adapted to be stationarily mounted to the aft end of vehicle22adjacent rear edge26of cargo floor24. Each column38A-B is generally linear and extends generally vertically between a bottom end40and a top end42. Columns38A-B are spaced apart from one another and are generally parallel to one another and are generally located at opposite ends of rear edge26of cargo floor24. Lift mechanism36also includes lifting posts44A and44B. Lifting post44A is operatively coupled to column38A and lifting post44B is operatively coupled to column38B. Each lifting post44A-B is generally linear and extends generally vertically between a bottom end46and a top end48. Lifting post44A is selectively vertically slideable with respect to column38A between a raised position wherein bottom end46of lifting post44A is adjacent bottom end40of column38A and a lowered position wherein bottom end46of lifting post44A is located adjacent the surface that supports wheels28and spaced apart from bottom end40of column38A. Lifting post44B is similarly selectively vertically moveable with respect to column38B between a lowered position and a raised position. Lifting posts44A-B are conjointly moveable between their raised position and lower position by a drive mechanism, such that lifting posts44A-B move vertically upwardly and downwardly in unison with one another.

Lift mechanism36includes a selectively moveable and foldable load platform50. Load platform50includes a proximal deck section52and a distal deck section54. Proximal deck section52is generally rectangular and includes a generally linear proximal edge56and a spaced apart and generally parallel and linear distal edge58. Proximal edge56and distal edge58extend generally parallel to rear edge26of cargo floor24and rotational axes30of wheels28. Proximal deck section52also includes a generally linear first side edge60and a spaced apart and generally parallel and linear second side edge62. First side edge60and second side edge62extend between and generally perpendicular to proximal edge56and distal edge58. Proximal deck section52includes a generally planar floor64mounted on a base. Floor64may comprise a plate, such as checkered plate. Proximal edge56of proximal deck section52is pivotally coupled to bottom ends46of lifting posts44A-B for pivotal movement about a pivot axis66. Proximal deck section52extends between bottom ends46of lifting post44A and44B with bottom end46of lifting post44A being located adjacent first side edge60of proximal deck section52and bottom end46of lifting post44B being located adjacent second side edge62of proximal deck section52. Pivot axis66is generally parallel to rear edge26of cargo floor24and rotational axes30of wheels28of vehicle22.

Distal deck section54is generally rectangular and includes a generally linear proximal edge76and a spaced apart and generally parallel and linear distal edge78. Proximal edge76and distal edge78are generally parallel to one another and to proximal edge56and distal edge58of proximal deck section52. Proximal edge76of proximal deck section52includes a plurality of hinge members80that are pivotally coupled to similar hinge members on distal edge58of proximal deck section52. Proximal edge76of distal deck section54is pivotally coupled to distal edge58of proximal deck section52for pivotal movement about a pivot axis82. Proximal deck section52and distal deck section54are pivotal with respect to one another about pivot axis82. Pivot axis82is generally parallel to pivot axis66.

Distal deck section54also includes a generally linear first side edge84and a spaced apart and generally parallel and linear second side edge86. First side edge84and second side edge86extend generally perpendicularly between proximal edge76and distal edge78. First side edge84of distal deck section54is located generally colinear with first side edge60of proximal deck section52when proximal deck section52and distal deck section54are in their generally horizontal extended positions. Second side edge86of distal deck section54is located generally colinear with second side edge62of proximal deck section52when proximal deck section52and distal deck section54are in their generally horizontal extended positions. Distal deck section54includes a generally planar floor88mounted on a base. Floor88may be formed from a plate, such as checkered plate.

Distal deck section54includes generally plate-like ledges90A-C that extend outwardly from the bottom of the base of distal deck section54and generally parallel to and below the floor88to an outer edge. Ledge90A extends along and outwardly from first side edge84of distal deck section54, ledge90B extends along and outwardly from second side edge86of distal deck section54, and ledge90C extends along and outwardly from distal edge78of distal deck section54. One or more inner abutment members92are attached to and extend along an upper surface of each ledge90A-C. One or more outer abutment members94are attached to and extend along an upper surface of each ledge90A-C. Each outer abutment member94is spaced outwardly from an inner abutment member92such that a channel96is formed between each inner abutment member92and its associated outer abutment member94.

Liftgate20includes side ramps100A and100B pivotally coupled to opposite sides of distal deck section54. If desired, liftgate20may include only one side ramp100A or100B as desired. Each side ramp100A-B includes a generally linear inner edge102and a spaced apart and generally parallel and linear outer edge104. Inner edge102of side ramp100A is located adjacent and generally parallel to first side edge84of distal deck section54and is pivotally coupled to first side edge84. Inner edge102of side ramp100B is located adjacent and generally parallel to second side edge86of distal deck section54and is pivotally coupled to second side edge86.

Each side ramp100A and100B also includes a generally linear first side edge106and a spaced apart and generally parallel and linear second side edge108. First side edge106and second side edge108extend generally perpendicularly between inner edge102and outer edge104. Each side ramp100A and100B is generally rectangular and plate-like and includes a generally planar top surface110and a generally planar bottom surface112. Each side ramp100A and B may be formed from a plate, such as checkered plate. Side ramps100A and100B are respectively located on opposite sides of distal deck section54. First side edges106of side ramps100A and B are generally parallel to proximal edge76of distal deck section54and are spaced apart from proximal edge76. Second side edges108of side ramps100A and B are located generally parallel to and adjacent distal edge78of distal deck section54.

Liftgate20includes an end ramp120that is pivotally coupled to distal edge78of distal deck section54. End ramp120is generally rectangular and plate-like. End ramp120includes a generally linear inner edge122and spaced apart and generally parallel and linear outer edge124. Inner edge122and outer edge124are generally parallel to proximal edges56and76and distal edges58and78of proximal and distal deck sections52and54. End ramp120also includes a generally linear first side edge126and spaced apart and generally parallel and linear second side edge128. First and second side edges126and128extend generally perpendicularly between inner edge122and outer edge124. End ramp120extends substantially the width of distal deck section54between first side edge84and second side edge86of distal deck section54. End ramp120includes a generally planar top surface130and a generally planar bottom surface132. End ramp120may be formed as a plate, such as checkered plate.

Proximal edge56of proximal deck section52comprises a proximal edge of load platform50, distal edge78of distal deck section54comprises a distal edge of load platform50, first side edge60and first side edge84of proximal and distal deck sections52and54comprise a first side edge of load platform50, and second side edge62and second side edge86of proximal and distal deck sections52and54comprise a second side edge of load platform50.

Liftgate20includes restraints140A and140B. Restraint140A includes a first end142coupled to first side edge84of distal deck section54and a second end144coupled to lifting post44A. Restraint140B includes a first end146coupled to second side edge86of distal deck section54and a second end148coupled to lifting post44B. Restraint140A includes a stanchion150A and a tether152A. Restraint140B includes a stanchion150B and a tether152B. Stanchions150A-B are constructed substantially identical to one another, although as a mirror image of one another. Tethers152A-B are constructed substantially identical to one another.

Each stanchion150A-B includes a generally elongate leg that extends generally linearly between a bottom end154and a top end156. Bottom end154of each stanchion150A-B includes a heel158and a toe160that extends outwardly in an opposite direction from heel158. Toe160includes an engagement member such as a shelf162. Each stanchion150A-B may comprise a post or a generally plate-like member. Stanchions150A-B are generally rigid.

Bottom end154of stanchion150A is pivotally coupled to first side edge84of distal deck section54adjacent the proximal end of first side edge84and adjacent proximal edge76of distal deck section54, and is spaced substantially apart from the distal end of first side edge84and apart from distal edge78of distal deck section54. Bottom end154of stanchion150B is pivotally coupled to second side edge86of distal deck section54and is located adjacent the proximal end of second side edge86and adjacent proximal edge76of distal deck section54, and is spaced substantially apart from the distal end of second side edge86and apart from distal edge78of distal deck section54. Stanchions150A and B are both pivotal with respect to distal deck section54about a common generally linear pivot axis164that is generally parallel to pivot axes66and82.

Each tether152A-B includes a first end166and a second end168. First end166of tether152A is coupled to top end156of stanchion150A and second end168of tether152A is coupled to lifting post44A. First end166of tether152B is coupled to top end156of stanchion150B and second end168of tether152B is coupled to lifting post44B. Each tether152A-B may comprise a flexible, foldable or collapsible member, such as a chain, cable, rope, scissors links or the like. Each tether152A-B is substantially non-elastic under tension, but is collapsible or foldable under compression. Each tether152A-B may be enclosed within a flexible protective sleeve if desired.

Liftgate20also includes support members174A and174B. Each support member174A-B extends between a first end176and a second end178. First end176of support member174A is coupled to a distal end of first side edge60of proximal deck section52and second end178of support member174A is coupled to lifting post44A. First end176of support member174B is coupled to the distal end of second side edge62of proximal deck section52and second end178of support member174B is coupled to lifting post44B. Each support member174A-B comprises a tether that may be constructed in the same manner as tethers152A-B. Support members174A-B may comprise a flexible, foldable or collapsible member such as a chain, cable, rope, scissors links or the like. Support members174A-B are substantially non-elastic under tension, but are collapsible or foldable under compression. If desired support members174A and B may be located within a flexible protective sleeve.

Side ramps100A-B and end ramp120are each respectively pivotally connected to distal deck section54by one or more hinges such as links184. Each link184is generally elongate and extends between a first end186and a second end188. First end186of each link184is pivotally coupled to distal deck section54for pivotal movement about an inner pivot axis190with respect to distal deck section54. Second end188of each link184is pivotally coupled to an inner edge of an associated side ramp100A, side ramp100B or end ramp120, such that the associated side ramp100A, side ramp100B or end ramp120is pivotal with respect to link184about an outer pivot axis192that is generally parallel to inner pivot axis190. Each ramp100A-B and120is thereby selectively pivotal with respect to distal deck section54between an operational position wherein ramp100A-B or120extends outwardly from distal deck section54such that the outer edge of the ramp is adapted to engage the loading surface, such as shown inFIG. 2, and a stored position as shown inFIG. 3wherein the ramp100A,100B or120overlies floor64of distal deck section54and does not extend outwardly beyond the edges of distal deck section54. When ramps100A,100B and120are pivoted to their stored positions, side ramps100A and100B are initially folded to their stored positions to overly floor64of distal deck section54and then end ramp120is pivoted to its stored position such that end ramp120overlies side ramps100A and100B and floor64of distal deck section54.

A ramp latch200is coupled to bottom surface112of each of side ramps100A and100B as shown inFIGS. 5 and 13A-B. Each ramp latch200includes a retaining member202and a pivotal lever204coupled to retaining member202. Retaining member202includes a first end106and a second end208pivotally coupled to lever204. Ramp latch200is selectively moveable between a locked position as shown inFIG. 13Aand an unlocked position as shown inFIG. 13B. A resilient biasing member210, such as a spring, resiliently biases retaining member202of ramp latch200toward the locked position. When ramps100A,100B and120are located in their stored positions as shown inFIG. 5, retaining members202of ramp latches200are adapted to overly a portion of end ramp120when ramp latches200are in their locked position such that retaining members202retain end ramp120in the stored position. End ramp120in turn retains side ramps100A and100B in their stored positions. Ramp latches200are moved to the unlocked position by manually pivoting lever204to retract retaining member202and compress biasing member210, such that lever204releasably retains retaining member202in the retracted and unlocked position and such that retaining member202no longer overlies end ramp120. End ramp120, and then side ramps100A-B, can then be selectively pivoted from their stored position towards their operational position.

As shown inFIG. 4, each of the ramps100A,100B and120may be pivoted with respect to distal deck section54to a generally upright retaining position that is between the operational position and the stored position of each ramp. When ramps100A-B and120are in the retaining position as shown inFIG. 4, each ramp is adapted to prevent cargo from falling off of distal deck section54and to retain cargo on distal deck section54. As shown inFIGS. 11 and 12, end ramp120is pivoted about outer pivot axis192to a generally vertical and upright position and is raised vertically about inner pivot axis190such that inner edge122of end ramp120is located above channel96on ledge90C. Inner edge122of end ramp120is then lowered into channel96such that inner edge122of end ramp120rests in engagement with ledge90C between inner abutment member92and outer abutment member94. When ramp120is in the retention position as shown inFIG. 11, inner edge122of end ramp120will engage either inner abutment member92or outer abutment member94when end ramp120is attempted to be pivoted in one direction or the other about outer pivot axis192such that, while some limited pivotal movement of end ramp120may be permitted about outer pivot axis192, end ramp120will be retained in the generally upright retention position.

When it is desired to move the end ramp120to either the operational position as shown inFIG. 12or the stored position as shown inFIG. 3from its retention position, end ramp120is lifted vertically upwardly such that inner edge122is removed from channel96whereupon end ramp120may be pivoted about outer pivot axis192to either the operational position or stored position as desired. Side ramps100A and100B are selectively positioned in the generally upright retention position as described in connection with end ramp120, wherein inner edge102of side ramps100A and B are selectively inserted or removed from a channel96between inner abutment members92and outer abutment members94of ledges90A-B. Each ramp100A,100B and120can be selectively positioned in its operational position, stored position or retention position independently of the other ramps.

Load platform50is selectively moveable by lift mechanism36between a lowered position as shown inFIG. 1wherein load platform50is located at a height below the height of cargo floor24of vehicle22and a raised position wherein the top surface of load platform50is located generally coplanar with the top surface of cargo floor24of vehicle22for movement of cargo between load platform50and cargo floor24. Load platform50is also selectively moveable or foldable between an extended position as shown inFIGS. 1 and 7and a retracted position as shown inFIG. 16.

When load platform50is in the extended position as shown inFIGS. 1 and 7, proximal deck section52and distal deck section54are located in extended positions and are located generally coplanar with one another such that the surfaces of floors64and88are generally horizontal and coplanar with one another. When load platform50is in the extended position, proximal edge56of proximal deck section52is vertically supported by lifting posts44A and B and distal edge58of proximal deck section52is vertically supported by support members174A and B. When load platform50is in the extended position, distal deck section54is vertically supported by its pivotal connection to proximal deck section52and by restraints140A and B. Restraints140A and B support distal deck section54and prevent pivotal movement of distal deck section54with respect to proximal deck section52about pivot axis82in a direction such that distal deck section54would pivot downwardly toward the loading surface.

When load platform50is in the extended position, stanchions150A and B of restraints140A and B are in a generally upright position generally perpendicular to floor88of distal deck section54, wherein heel158of each stanchion150A and B engages a respective rear lug214. Rear lugs214are respectively coupled to and extend outwardly from first side edge84and second side edge86of distal deck section54. Shelf162of toe160of each stanchion150A and B also engages a respective forward lug216. Forward lugs216are respectively connected to and extend outwardly from first side edge84and second side edge86of distal deck section54. Each stanchion150A and B is pivotal about axis164between an operational position wherein each stanchion150A-B is substantially upright and perpendicular to distal deck section54and a stored position wherein each stanchion150A-B is substantially parallel to distal deck section54. Each rear lug214and forward lug216respectively engages a stanchion150A or B when stanchions150A-B are in the upright operational position and prevent pivotal movement of stanchions150A and B about axis164beyond the upright operational position in a direction away from the stored position.

Liftgate20also includes one or more locking mechanisms220coupled to load platform50. Locking mechanism220includes a receiver222coupled to proximal deck section52adjacent proximal edge56. Receiver222includes a receptacle224having an open top end. Locking mechanism220also includes a coupler226having a pin228. Coupler226is pivotally coupled to distal deck section54adjacent proximal edge76. When load platform50is in the extended position, coupler226is adapted to be pivoted to a locked position wherein pin228is located within receptacle224of receiver222whereby locking mechanism220prevents downward pivotal movement of distal deck section54about pivot axis82with respect to proximal deck section52. Coupler226may be selectively pivoted to an unlocked position wherein pin228is removed from receptacle224wherein locking mechanism220does not prevent pivotal movement of distal deck section54with respect to proximal deck section52about pivot axis82.

Liftgate20also includes an actuator234having a first end236and a second end238. Actuator234may comprise a hydraulic cylinder having a housing and an extendable and retractable ram. First end236of actuator234is coupled to proximal edge56of proximal deck section52by a link240. Second end238of actuator234is coupled to lifting post44B. Actuator234is adapted to selectively pivot load platform50between the extended position of load platform50and the retracted or folded position of load platform50.

When load platform50is in the extended position, and ramps100A,100B and120are in their stored positions, actuator234is adapted to pivot proximal deck section52about pivot axis66from a generally horizontal extended position to a generally vertical retracted position. As distal edge58of proximal deck section52pivots upwardly about pivot axis66, distal edge78of distal deck section54pivots downwardly with respect to proximal deck section52about pivot axis82such that distal deck section54pivotally moves from a generally horizontal extended position toward a generally vertical retracted position. As proximal deck section52and distal deck section54pivot from their horizontal extended positions toward their folded vertical retracted positions, support members174A and B are relieved of their tensile support loads and collapse.

Initially, as proximal deck section52and distal deck section54pivot from their horizontal extended positions toward their folded vertical retracted positions, restraints140A and B continue to support distal deck section54and inhibit distal deck section54, as shown inFIG. 6, from pivoting about pivot axis82to a generally vertical position until proximal deck section52and distal deck section54have been sufficiently pivoted and folded about pivot axis82whereupon top ends156of stanchions150A and B pivot downwardly about axis164with respect to distal deck section54from the operational position of stanchions150A and B toward the stored positions of stanchions150A and B. The tensile load of tethers152A and B of restraints140A and B is then relieved such that tethers152A and B may collapse. When load platform50is in the retracted and stored position, a latch244may selectively lock load platform50in the retracted position.

Load platform50may be moved from the folded and retracted position toward the extended position wherein proximal deck section52and distal deck section54are generally coplanar and horizontal in substantially the opposite manner as described in connection with the retraction of load platform50to the retracted position.

When load platform50is in the extended position, each of side ramps100A,100B and end ramp120may be selectively positioned in their upright retention positions or in their outwardly extending operational positions for the movement of cargo between distal deck section54and the loading surface. As shown inFIG. 2, side ramp100A is pivotally coupled to first side edge84of distal deck section54and is located between stanchion150A and distal edge78of distal deck section54. Side ramp100B is similarly pivotally coupled to second side edge86of distal deck section54and is located between stanchion150B and distal edge78of distal deck section54. Unobstructed pathways are thereby provided between side ramp100A and distal deck section54and between side ramp100B and distal deck section54. Side ramps100A and B thereby provide for unobstructed side loading of distal deck section54with cargo in a direction transverse to the longitudinal axis of vehicle22. Restraints140A and B are respectively located between lifting posts44A and B and first side edges106of side ramps100A and B such that restraints140A and B do not interfere with pivotal movement of side ramps100A and B between their operational and stored positions, and do not interfere with or obstruct the pathways between side ramps100A and B and distal deck section54when side ramps100A and B are in their operational positions.

Side ramps100A and B enable unobstructed movement of cargo between side ramps100A and B and distal deck section54and thereby between a loading surface and distal deck section54. Cargo may be side loaded onto distal deck section54by individuals walking across side ramps100A and B onto distal deck section54, or by mechanisms such as hand carts or dollies that roll or otherwise move from the loading surface, over side ramps100A or B and onto distal deck section54. Cargo may be similarly side unloaded from distal deck section54by way of side ramps100A-B. When load platform50is in the extended position and is raised by lift mechanism36to the raised position, cargo may be moved between distal deck section54and proximal deck section52of load platform50and cargo floor24of vehicle22.

Various features of the invention have been particularly shown and described in connection with the illustrated embodiment of the invention, however, it must be understood that these particular arrangements merely illustrate, and that the invention is to be given its fullest interpretation within the terms of the appended claims.