Abstract:
A secure loading system operates with a wheelchair lift attached to a vehicle, securing the wheelchair to a platform during the lifting motion and retracting the platform into the vehicle once the wheelchair has been lifted, or performing a reverse operation wherein the platform is extended to the lift for lowering the wheelchair. The secure loading system may be an after-market add-on to a lift, or may be integrated into the lift at design time. The system may also be adapted for many other embodiments wherein a secured platform is needed during a lifting motion.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application 61/052,472, filed May 12, 2008. 
    
    
     BACKGROUND 
     This specification relates to the field of mechanical lifting systems and more particularly to a secure loading system for use in a lifting system. 
     Lifting systems such as wheelchair lifts may include a platform for carrying a load and a hydraulic or other mechanical system for lifting. In some such lifting systems, the load may be susceptible to shifting or other unsecured motion during the lifting process, which may lead to either physical injury or harm to goods. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an exemplary embodiment of a secure loading system; 
         FIG. 1A  is a detail view of an exemplary embodiment of an actuator for use with a secure loading system; 
         FIG. 1B  is a detail view of an exemplary embodiment of a t-shaped connector engaging a t-shaped slot; 
         FIG. 2  is a side-view of an exemplary embodiment of a secure loading system; 
         FIG. 3  is a top-view of an exemplary embodiment of a secure loading system; 
         FIG. 4A  is an additional top-view of a secure loading system; 
         FIG. 4B  is an additional perspective view of an exemplary embodiment of a secure loading system; 
         FIG. 4C  is an additional side-view of a secure loading system; 
         FIG. 4D  is a front view of an exemplary embodiment of a secure loading system; 
         FIG. 5  is a perspective view of an exemplary embodiment of a secure loading system, more particularly disclosing a state wherein the secure platform is disengaged from the support frame; 
         FIG. 6  is a perspective view of an exemplary embodiment of a secure loading system more particularly disclosing a fully extended state; 
         FIG. 7  is an exemplary embodiment of a platform and track system more particularly disclosing a partially extended state; 
         FIG. 8  is an exemplary embodiment of a secure loading system, more particularly disclosing a fully retracted state; 
         FIG. 9  is an exemplary embodiment of a secure loading system disclosing a feature whereby a lift platform is used to provide structural stability to a shoulder restraint securing bar; and 
         FIG. 10  is a perspective view of an alternative embodiment of a platform. 
     
    
    
     SUMMARY OF THE INVENTION 
     In one aspect, a secure loading system operates with a wheelchair lift attached to a vehicle, securing the wheelchair to a platform during the lifting motion and retracting the platform into the vehicle once the wheelchair has been lifted, or performing a reverse operation wherein the platform is extended to the lift for lowering the wheelchair. The secure loading system may be an after-market add-on to a lift, or may be integrated into the lift at design time. The system may also be adapted for many other embodiments wherein a secured platform is needed during a lifting motion. 
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     A secure loading system is used to secure a load to a platform during a lifting or lowering motion, and to provide the ability to move the load into a desired position. An embodiment disclosed herein discloses that the load may be a wheelchair, but this is not intended to limit the invention to the specific embodiment described in the figures. A secure loading system may be useful for a variety of different types of lifts and loads. Furthermore, a secure loading system may be provided either as an after-market add-on to an existing lift system, or may be integrated into a lift system. 
     A secure loading system will now be described with more particular reference to the attached drawings. Hereafter, details are set forth by way of example to facilitate discussion of the disclosed subject matter. It should be apparent to a person of ordinary skill in the field, however, that the disclosed embodiments are exemplary and not exhaustive of all possible embodiments. Throughout this disclosure, a hyphenated form of a reference numeral refers to a specific instance or example of an element and the un-hyphenated form of the reference numeral refers to the element generically or collectively. Thus, for example,  102 - 1  may refer to a “pen,” which may be an instance or example of the class of “writing implements.” Writing implements may be referred to collectively as “writing implements  102 ” and any one may be referred to generically as a “writing implement  102 .” 
       FIG. 1  is a perspective view of an exemplary embodiment of a secure loading system. In this embodiment, a platform  110  rests on a support frame  180 . Platform  110  may be constructed of any suitably rigid material, including, by way of non-limiting example metals, plastics, composites. For example, platform  110  may be constructed of ⅜″ steel. The design and composition of platform  110  may be tailored to support load  190 . In the disclosed embodiment, the load  190  is a wheelchair  190 - 1 . Load  190  may be secured to platform  110  by means suitable for preventing shifting, sliding, or other movement relative to the platform. For example, in the case of wheelchair  190 - 1 , a four-point tie-down system may be employed to secure wheelchair  190 - 1  to platform  110 . Other possibilities will be apparent to those of skill in the art. 
     Platform  110  may be mechanically coupled to support frame  180  by framework tracks  510  ( FIG. 5 ). In some embodiments, support frame  180  may be fixedly attached to a lift platform (not shown); for example, support frame  180  may be bolted to the lift, which in some cases may contain a separate lift platform that is a fixed part of the lift. The lift may be any of numerous lifts available in the art, such as the lifts disclosed in U.S. Pat. No. 4,121,695 to Carpenter, U.S. Pat. No. 4,252,491 to Hock, and U.S. Pat. No. 5,065,844 to Hon, among others. In other embodiments, a lift system may be designed from the ground up according to the present invention, such that platform  110  is an integral part of the lift. In this case, support frame  180  and platform  110  may be unnecessary as separate attachments, as they may be functionally integrated into an off-the-shelf lift platform. Platform  110  may include platform rails  112  which may be configured slidably engage framework tracks  510  ( FIG. 5 ), so that platform  110  may easily move relative to support frame  180  and freely engage or disengage support frame  180 . To achieve the configuration disclosed in  FIG. 1 , the lift mechanism would be in the “up” position so that the platform  110  is substantially coplanar with mechanical guide  160 . A mechanical guide, as used herein, is any device or mechanism designed to guide a platform such as platform  110 , and may include a framework, tracks, mounting structures, and any other components suited to its purpose. Also per the disclosed embodiment, mechanical guide  160  provides the supporting framework on which platform  110  rests in its retracted position inside a vehicle. A vehicle, as used herein, includes motor vehicles as per the exemplary embodiment, as well as any other mobile or stationary structure into which the load  190  is to be transferred. In some embodiments, mechanical guide  160  may be separate from an interior support structure. In this configuration, arm extensions  122  are extended to couple mechanical guide  160  to support frame  180 . Arm extensions  122  provide an extension of track  120 , which may be a C-channel tracker, which may allow platform  110  to travel freely from the fully extended position shown in  FIG. 1  to a fully retracted position, as shown in  FIG. 8 . In this embodiment, a drive shaft  150  is provided to engage platform  110 , and is rigid so that the drive shaft  150  may either push the platform  110  to an extended position, or pull it inward to a retracted position. In this embodiment, drive shaft  150  is biased downward, for example with a spring loaded mechanism, so that it firmly engages platform  110  when platform  110  is in the raised position, and also easily disengages when platform  110  is lowered. Drive shaft  150  may terminate in a T-shaped connector  154  ( FIG. 1B ), which may engage T-shaped slot  182  ( FIG. 1B ). While a T-shaped connector  154  is disclosed, persons have skill in the art will recognize that many securing devices will provide the same or similar functionality. 
     Drive shaft  150  is actuated by a linear actuator  152 - 1  ( FIG. 1A ), which is a species of actuator  152 . Linear actuator  152 - 1  includes an electric motor  140 , with a rotor  144  engaging a belt  146  which turns a pulley  142 . Pulley  142  is fixedly connected to an end of screw  148 , which forms part of a nut and screw transducer. Drive shaft  150  is mechanically affixed to screw  148  by nut  149 . In this configuration, when electric motor  140  turns, screw  148  engages nut  149  causing drive shaft  150  to either retract or extend the platform. Screw  148  may be partially enclosed by a screw encasement  170 , which may be made of a rigid polymer or other rigid material. Screw encasement  170  provides some mechanical protection for screw  148 . As platform  110  is extended or retracted, platform rails  112  will move along track  120 , which may be a C-channel track. When platform  180  is engaged with arm extensions  122 , platform  180  and arm extensions  122  may be secured to each other by hinged locks  124 . A platform lock  130  is provided to secure platform  110  when in a fully-retracted position. Platform lock  130  may be biased downward so that it automatically engages platform  110  in a fully-retracted position. Persons having skill in the art will recognize that a downward-biased latch mechanism is one of only many possible embodiments of a platform lock  130 . For example, Q&#39;Straing provides a commercially-available “QLK-100” docking system, which employs securing brackets. Such a system would also be suitable for platform lock  130 , as would any other device configured to secure platform  110  to mechanical guide  160  when in a fully-retracted position. 
     Although a linear actuator and drive shaft has been disclosed as an exemplary embodiment, other configurations may achieve the same result. For example, platform  110  may have an internal motor to provide the function of an actuator, in which case the drive mechanism may be provided by wheels and axles. The terms “actuator” and “drive” as used herein are intended to broadly encompass any such system intended to actuate motion in platform  110 . 
       FIG. 2  is a side view of an exemplary embodiment of a secure loading system  100 . This embodiment more clearly discloses shoulder restraint securing bar  210 , which may be provided so that an occupant of wheelchair  190 - 1  can use a shoulder restraint while riding in a vehicle. Shoulder restraint securing bar  210  may help ensure that secure loading system  100  complies with applicable safety laws. Also visible in this view are orthogonal stabilizing bars  230 . These help to ensure the structural integrity of the support frame  180  under load  190 . 
       FIG. 3  is a top view of a secure loading system  100 . In this view, wheelchair tie-downs  310  are visible. Wheelchair tie-downs  310  are provided to secure the wheelchair  190  to platform  110 . In this example, a four-point tie-down is used. Suitable four-point mechanisms are available from commercial vendors. For example, Q&#39;Straint provides an L-track floor anchor, an oval 1-pocket anchor, a slide and click anchor, a pocket floor anchor, and an A-plate anchor. In other embodiments, other securing mechanisms  310  may be used to secure load  190  to wheelchair platform  110 . For example, Q&#39;Straint provides the QLK-100 docking system, which is bracket-based, or in other embodiments, tether-based restraints may be used. 
       FIG. 4A  is an additional top view of an exemplary embodiment of a secure loading system  100 . 
       FIG. 4B  is an additional perspective view of an exemplary embodiment of a secure loading system  100 . 
       FIG. 4C  is an additional side view of an exemplary embodiment of a secure loading system  100 . 
       FIG. 4D  is a front view of an exemplary embodiment of a secure loading system  100 . 
       FIG. 5  is an additional perspective view of an exemplary embodiment of a secure loading system  100 . In this view, arm extensions  122  are unlocked from hinged locks  124  and disengaged from support frame  180 . With arm extensions  122  disengaged from support frame  180 , guide tracks  510  are more plainly visible. In this view, it can be seen that guide tracks  510  may be C-channel tracks configured to receive platform rails  112 . Also more plainly visible in this view are orthogonal stabilizing bars  230 . 
     In this view it is more apparent that in some embodiments, platform  110  and mechanical guide  160  may completely disengage from support frame  180  at certain times. In some embodiments, this is necessary because support frame  180  will be attached to a lift platform (not shown). The lift platform may need to move independently of platform  110  and support frame  160 . This will allow the mechanical lift platform to freely move up and down through its lifting and lowering motion. 
       FIG. 6  discloses an additional perspective view of an exemplary embodiment of a secure loading system. In this embodiment, secure platform  110  is in its completely extended position. In this configuration, platform locks  124  are ready to be disengaged from arm extensions  122 . When these are disengaged from each other, platform  110  is resting on support frame  180 , which may be attached to (or an integral part of) a lift platform, and load  190  may be lowered by the mechanical lift. The position shown in  FIG. 6  is also the position in which the system will be after the mechanical lift has been moved to its fully raised position. Because drive shaft  150  may be biased downward, whenever support frame  180  raises platform  110  to a fully raised position, T-shaped connector  154  may automatically seat into t-shaped slot  182 . The downward bias of drive shaft  150  may help to ensure that the coupling of t-shaped connector  154  to t-shaped slot  182  is mechanically secure. 
       FIG. 7  is yet another perspective view of a secure loading system  100 , showing platform  110  in a partially-extended position. 
       FIG. 8  is yet another perspective view of a secure loading system  100  showing platform  110  in a fully-retracted position. 
       FIG. 9  is an exemplary embodiment of a secure loading system wherein a lift platform  920  may be raised to provide additional structural support to shoulder restraint securing bar  210 . In this case, lift platform  920  may be designed as an integral part of the lift, and may be the same as platform  110 . Lift platform  920  is designed to move into an upright position when the lifting maneuver is completed as the arrows illustrate. Lift platform  920  includes a cam  930 , which is configured to engage latch  910  when lift platform  920  is raised. Although a latch  910  and cam  930  are disclosed, persons having skill in the art will recognize that it is trivial to either have the latch  910  and cam  930  trade places with each other, or to use an alternative securing system such as a magnet, hook, cord, interlock, tie or other suitable mechanism. Alternatively, lift platform  920  may be an off-the-shelf platform for a lift, and support frame  180  may provide cam  930  or an alternative mechanism. 
       FIG. 10  shows an alternative embodiment of a platform  110 , in which is disclosed an alternative method of providing additional security and structural support to shoulder restraint securing bar  210 . In this embodiment, platform  110  includes a folding panel  1010 , which may be folded up behind load  190  when load  190  is secured to platform  110 . This provides additional safety from back rolling. Folding panel  1010  rotates on hinges  1030 , and may be secured with a latch and cam mechanism or other suitable securing device. 
     The secure loading system as described structurally above may enable a method of loading a load into a vehicle, which may include the following illustrative steps. First, a load  190  may be secured to a platform  110 , which is either attached to or part of a lift. The lift may then be caused to actuate a vertical motion, whereby the platform  110  is brought into a position substantially coplanar with mechanical guide  160 , in an extended position. Next, an actuator  152  may be used to actuate horizontal motion in platform  110 , whereby platform  110  is moved into a retracted position within the vehicle. Finally, the platform  110  may be secured within the vehicle. 
     Conversely, a method for unloading a load  190  from a vehicle is also enabled. In this case, platform  110  may be unsecured from the vehicle, and actuator  152  may be used to actuate horizontal motion in platform  110 , whereby platform  110  is moved from a retracted position to an extended position that is substantially coplanar with mechanical guide  160 . The lift is then used to provide vertical motion, moving load  190  to a plane either above or below mechanical guide  160 . 
       FIG. 1  also illustrates a lift  168 . Lifts  168  are known in the prior art. Support frame  180  is mechanically fixed to the lift and platform  110 . The lift is enabled to raise and lower the platform. 
     While the subject of this specification has been described in connection with one or more exemplary embodiments, it is not intended to limit the claims to the particular embodiments set forth. On the contrary, the appended claims are intended to cover such alternatives, modifications and equivalents as may be included within their spirit and scope.