for purpose of understanding the invention , reference will now be made to embodiments illustrated in the drawings . whenever in general the open position or operational position is mentioned , refer to fig1 and 2 . if the canopy assembly is being described as in the process of either being opening or retracting refer to fig3 . the generally described retracted position is shown in fig4 and 5 . refer to fig6 , 7 , 8 , 9 , and 10 for specific component references . fig1 illustrates an alternate embodiment . the whole operation of the canopy assembly is controlled by the user with a switch 38 . in an exemplary model this is a three - way push switch , mounted at the wheelchair arm rest , and it is either in the open , neutral , or retract position . the three - way switch allows for the canopy operation to be stopped at any position during operation with the option to then open or retract the canopy assembly after it has been stopped . this gives the user the ability to stop the operation of the canopy at any time and then either continue in the same direction or reverse back . the entire mechanism is mounted to the main mount bracket 16 . in an exemplary embodiment , all the mechanical , electrical and structural components are mounted to the main mount bracket 16 . this configuration allows simple and fast installation of the canopy assembly to the wheelchair backrest 15 . bolts attach the main mount bracket 16 to the backrest 15 . in an exemplary embodiment , the main mount bracket 16 mounting hardware 1 and 19 is specific to one kind of wheelchair with rails on the seat backrest 15 . in general the main mount bracket 16 can be configured to mount to a different variety of wheelchairs , scooters or any other vehicles with a combination of specific or adjustable bolts , clamps or brackets . the motor 7 is mounted to the main mount bracket 16 by the motor mount plate 17 and the motor mount block 20 . in an exemplary embodiment the motor 16 is a gear motor with a low rpm and high torque . referring to fig8 , the gear motor 7 provides rotational force about the vertical axis and transfers it , with the use of a coupling 4 and worm shaft 8 , to a worm 11 . the worm 11 , coupling 4 , and worm shaft 8 assembly remains structurally sound because of the mounted bearing 13 , which is bolted to the main mount bracket 16 . a collar 18 that connects to the worm shaft 8 also provides structural support and alignment for the worm 11 and coupling 4 assembly . the worm 11 transfers a rotational force to the worm gear 12 and the main shaft 9 and changes the force to the rotational motion along the horizontal axis . the main shaft 9 is held in place by the main mounted bearings 13 , which connect to the main bracket 16 . the collars 18 provide lateral alignment for the main shaft 9 , worm gear 12 , main mounted bearings 13 and limiter mount brackets 24 . referring to fig7 , the limiter bolts 10 and 14 are attached to the main shaft 9 through the limiter mount brackets 24 . referring to fig8 , the canopy assembly consists of two ( 2 ) unshaped tube ribs 3 and 5 attached to the main shaft 9 . the upholstery 22 is attached to the structural members 3 and 5 . the upholstery material 22 is vinyl in an exemplary embodiment but the upholstery 22 can be made out of any material that will satisfy these requirements : water resistant if the canopy will be used for rain protection , ability to block the sun for sun protection , flexible and strong enough to withstand pulling and folding during operation . rib 15 is attached to the main shaft 9 through the rod end 130 and it is pinned to the main shaft 9 by a quick release safety pin 29 constraining the movement to be dependent to the rotation of the main shaft 9 . the purpose of the quick release safety pin 29 is to be a safety device allowing manual canopy operation in case of a battery , motor or gear ( s ) malfunction . when the quick release pin 29 is pulled out , it allows free movement of rib 15 by removing a rigid connection between the rod end 130 and the main shaft 9 . rib 23 is attached to the main shaft through rod end 22 and is allowed is rotate freely about the horizontal axis independent of the main shaft 9 rotation . plain bearing 6 reduces friction between the rod end 22 and the main shaft 9 . the basic operation of the canopy assembly will now be described . the electrical power to the control switch 38 and motor 7 is provided from the wheelchair batteries . in an exemplary embodiment , a power wheelchair is used that already has a battery system onboard . if the vehicle does not have its own battery system , an add - on battery pack can be installed . when the gear motor 7 is engaged by the control switch 38 at the arm rest to open the canopy , the motor 7 and main shaft 9 turn forward and the main shaft 9 lifts rib 15 from the retracted position to the open position . rib 15 pulls the canopy material 22 and the canopy material 22 pulls rib 23 to the open position . when the canopy assembly is close to being in the fully open position , the rib 23 comes in contact with the extend stop 31 . this locks rib 23 in the vertical position and constrains any further forward movement . rib 15 continues to rotate and it pulls all the slack out of the canopy material 22 until the open position limit switch 23 is engaged by the open position limiter bolt 14 . that cuts the forward direction power off from the motor 7 and locks the canopy assembly in the open position . the “ one way ” property of worm gears , e . g ., worm 11 and worm gear 12 , locks the canopy assembly and prevents any unintended movement of the assembly when the gear motor 7 is not operating . when the control switch 38 is pushed to retract and engages the motor 7 to turn in the reverse direction , the main shaft 9 turns the rib 15 again but now in the retracting direction . as the rib 15 starts to turn the first thing that happens is tension in the canopy material 22 is released . as the rib 15 continues to rotate back , it pushes back the canopy material 22 . then the canopy material 22 pushes rib 23 back to the retracted position . rib 23 rotates until it comes in contact with the retract stop 32 . retract stop 32 prevents rib 23 from moving any further back . as rib 15 continues to move back , it compresses the canopy material 22 until the retracted position limit switch 21 is activated by the retracted position limiter bolt 10 which in turn cuts off the power to the gear motor 7 in the reverse direction . the limiter lock nuts 25 and limit switches 21 , 23 combination allow manual adjustment of when the limit switches 21 , 23 are engaged in both the extended and retracted position . this allows the final position in the fully open and retracted position of rib 15 to be adjustable . in the combination of all the components described above creates a canopy mechanical and structural assembly that is compact and simple . the combination of mechanical drive - train components and positioning of those components such as the motor 7 , worm 11 , worm gear 12 and mating to the main shaft 9 creates a compact drive - train that does not create any significant obstructions . in an exemplary embodiment , the gear motor 7 rotates at 25 revolutions per minute and then worm 11 and worm gear 12 reduce the rotational speed by a factor of 20 so that the main shaft rotates at approximately 1 . 25 rpm . the motor and gears combination result in the canopy movement from the retracted to open position and vice versa to last around thirty ( 30 ) seconds . this speed of operation creates the right balance of motion . if the ribs 3 , 5 along with the canopy material 22 were to move too fast , a potentially unsafe situation could be created . on the other hand , if the operation takes too long , that would create an inconvenience for the user . a safety system can be added to stop all moving parts in case of a mechanical jam or an obstruction , such as clothing or a body part , encountered during operation . to accomplish that a potentiometer and a motor controller can be added to the motor &# 39 ; s 7 circuit that will detect excessive electrical current draw during operation and will prevent any further movement and will either stay stopped or back off the opposite way . in an exemplary embodiment , the combination of the ribs 3 , 5 and rod ends 2 and 30 that provide mounting to the main shaft 9 allow the canopy assembly to fit within the footprint of the wheelchair . this is a useful feature as the canopy assembly is not wider than the wheelchair itself and the wheelchair can still fit through tight spaces such as doors and narrow hallways . at the same time user space is maximized as the ribs 3 , 5 and canopy material 22 shall not interfere with the person sitting in the chair . also , ribs 3 and 5 are made out of hollow aluminum tubing that is light and flexible when excessive load is applied . as a result , when heavy wind gusts are experienced , the ribs 3 and 5 will tend to flex therefore absorbing the wind forces that might otherwise flip the wheelchair over to the side . to further reduce the wind drag forces , the canopy material 22 side and back sections can be made out of material that lets the air through such as a mesh material . an alternate version of the invention is a similar design , in which instead of utilizing two ( 2 ) rib assemblies 2 , 5 there can be three ( 3 ) rib assemblies . refer to fig1 . as far as the mechanical system is concerned , the only difference would be the additional third middle rib and associated hardware . the additional rib 3 would function as a structural member only , allowing rib 15 to extend further to the front . the advantage of 3 rib design is greater front protection against sun and rain . the disadvantage is a more complicated design and limiting of front and side visibility . any canopy material 22 that is directly in the front and to the side of a user would have to be transparent .
a folding canopy for a mobility device , such as a wheelchair or scooter , can be displaced , via switch activation , from a folded position behind the backrest to the operating position above the mobility device . in the folded position , the canopy and structural members are kept behind the backrest . a press of the switch located on the armrest activates an electric motor and drives a mechanical assembly comprising of : two gears a shaft and two u - shape tubular structural members attached to weather resistant upholstery . the canopy and structural members assemble directly above the vehicle . another press of the switch retracts the canopy .