Abstract:
A universal adjustable-position mobility device for multiple use applications including robotics, industry and handicapped mobility facilitation. The device can be used to transport objects across varied terrain including inclines and declines and by utilizing a sliding extensible track system can bridge obstacles and traverse mud, sand and snow. The device further incorporates features which allow raising and lowering of the center of gravity of the load. By extending the rear wheels, the angle of the track mechanism relative to the ground to can be adjusted to facilitate engagement of the tracks with an abrupt incline such as when loading a wheelchair onto a vehicle.

Description:
FIELD OF THE INVENTION 
     The invention relates to motorized land mobility devices for transporting loads over a variety of terrain in robotic, industrial and handicapped uses. In particular, the present invention incorporates a motorized track mechanism for propelling robots and load carrying apparatus. 
     BACKGROUND OF THE INVENTION 
     The use of endless traction belts is well known in the field of land vehicles. Endless traction belts have been used in earthmoving equipment as well as in military equipment such as tanks and half-tracks. Endless traction belts have previously been applied in the field of wheel chairs as described in U.S. Pat. No. 4,044,850. In that patent, the wheelchair made use of both conventional wheelchair wheels in combination with an endless track mechanism, but the use of the track mechanism in that patent is limited to incline/decline situations such as stairs and is not used for to overland travel. 
     These and -other mechanisms have permitted the operator of the machine to navigate inclines and varied terrain. However, none of the prior tracked mechanisms provide for track adjustment capability to enable use of the track mechanism over a variety of terrain. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     It is an object of the invention to provide a mobility device capable of traversing a variety of terrain. 
     It is another object of the invention to provide a mobility device for use in robotics, industry and wheelchairs. 
     Still another object of the invention is to provide a mobility device having adjustable track mechanisms. 
     Yet another object of the invention is to provide a mobility device having in combination height adjustable wheels and a track mechanism. 
     Still another object of the invention is to provide a split track mechanism which can be extended and retracted. 
     It is a further object of the invention to provide a load carrier that can be adjusted to maintain a horizontal position when the mobility device ascends an incline. 
     Yet another object of the invention is to provide a system of clutches in combination with the track system to permit turning of the device when being propelled by the track system. 
     Still another object of the invention is to provide a mobility device which is capable of alternatively wheeled or track propulsion. 
     These and other objects of the present invention will be readily apparent upon review of the following detailed description of the invention and the accompanying drawings. These objects of the present invention are not exhaustive and are not to be construed as limiting the scope of the claimed invention. Further, it must be understood that no one embodiment of the present invention need include all of the aforementioned objects of the present invention. Rather, a given embodiment may include one or none of the aforementioned objects. Accordingly, these objects are not to be used to limit the scope of the claims of the present invention. 
     In summary, the invention is directed to a universal adjustable-position mobility device for multiple use applications including robotics, industry and handicapped mobility facilitation. The device can be used to transport objects across varied terrain including inclines and declines and by utilizing a sliding extensible track system can bridge obstacles and traverse mud, sand and snow. The device further incorporates features which allow raising and lowering of the center of gravity of the load. By extending the rear wheels, the angle of the track mechanism relative to the ground to can be adjusted to facilitate engagement of the tracks with an abrupt incline such as when loading a wheelchair onto a vehicle. 
    
    
     With these and other considerations in mind, as will become apparent hereinafter, the invention includes certain novel features of construction, combination and arrangement of parts and portions as will be set forth in the appended claims, reference being had to the accompanying drawings and detailed description thereof. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side view of the mobility device configured as a wheelchair. 
     FIG. 2 is a top view of the mobility device of FIG.  1 . 
     FIG. 2A is a schematic diagram of a top view of the mobility device of FIG. 1 
     FIG. 3 is an exploded view of the track mechanism of the mobility device of FIGS. 1 and 2. 
     FIG. 4 is a front view of the mobility device of FIG.  1 . 
     FIG. 5 is a rear view of the mobility device of FIG.  1 . 
     FIG. 6 is a sectional view of one side of the track mechanism taken along lines  6 — 6  of FIG.  2 . 
     FIG. 7 is a side view of the mobility device having the track mechanism lowered in a horizontal retracted position. 
     FIG. 8 is a side view of the mobility device of FIG. 8 wherein the tracks are extended. 
     FIG. 9 is a side view of the mobility device being used to ascend a step. 
     FIG. 10 is a side view of the mobility device ascending a set of stairs. 
     FIG. 11 is a sectional view of the central carriage of the mobility device taken along lines  1 — 1  of FIG.  2 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The most preferred forms of the invention will now be described with reference to FIGS. 1 through 11. The appended claims are not limited to the most preferred forms and no term used herein is to be given a meaning other than its ordinary meaning unless accompanied by a statement that the term “as used herein is defined as follows”. 
     The mobility device  10  as shown in the accompanying drawings is described with reference to its use as a wheelchair, but it should be understood that various features of the invention are adaptable to other uses such as in the fields of robotics and industry. 
     FIG. 1 shows a mobility device  10  adapted for use as a wheelchair  12  having a seat  14 , a backrest  16  and foot rests  18  all supported by a base frame  20 . A pair of front drive wheels  22  are positioned beneath the seat  14 . A pair of rear wheels  24  are mounted to telescoping shafts  26  connected to frame  20  by braces  28 . An electric motor  30  drives the telescoping shafts  26  to raise and lower the rear wheels  24 . The telescoping shafts  26  preferably incorporate a screw drive mechanism to extend and retract shafts  26 . 
     A left track mechanism  32  is mounted to the side of the frame  20 . As shown in FIG. 1, the left side track mechanism  32  is connected to the frame  20  at two attachment points, a motor-driven toothed spur gear  34  mounted on the frame  20  connects to a toothed arc gear  36  on the track mechanism  32  and a drive shaft  38  connects to the track mechanism drive gear  40 . In order for the track mechanism  32  to pivot from the lifted position to the lowered position, the spur gear  34  drives the arc gear  36  to pivot track mechanism  32  down as shown in phantom in FIG.  1 . The arc  36  travels along the spur gear  34  about the axis of the drive shaft  38  so that the arc  36 . remains equidistant from drive shaft  38  along its entire length as it travels along spur gear  34 . The spur gear  34  is powered by an electric drive motor  41 , preferably a Superwinch 62/63 series 24 volt motor located behind the backrest  16 . 
     Now with reference to FIGS. 1,  2  and  2 A, the mobility device  10  is shown as seen from above includes the left track mechanism  32  and the right track mechanism  42 . Right track mechanism  42  includes a central carriage  44  which is removeably connected to arc gear  36  via pins  46  and clips  48 . A drive motor  50  and transmission  51  mounted on the base frame  20  and includes a drive shaft  38  extending outwardly therefrom and is removably connected by a pin  52  to track mechanism drive gear  40  which is formed by a sprocket  54 . 
     Right track mechanism  42  includes an inside track carriage  60  and an outside track carriage  62 . The inside track carriage  60  is extensible and retractable relative to the central carriage  44  by a screw-driven telescoping extender  64 . The telescoping extender  64  includes an electric motor, preferably a 24 volt Superwinch 62/63 series 24 volt motor. The telescoping extender  64  is mounted by a brackets  68  and  70 . Bracket  68  is mounted on a brace  72  connected to the central carriage  44 . Bracket  70  is mounted near the rear end  74  of inside track carriage  60  with the telescoping extender  64  spanning the brackets  68  and  70 . The outside track carriage  62  similarly includes a telescoping extender  76  mounted by brackets  78  and  80  with bracket  78  mounted to brace  72  and bracket  80  mounted to the forward end  82  of outside track carriage  62 . Each of the telescoping extenders  64  and  76  are moveable independently of each other so that either the inside track carriage  60  or the outside track carriage  62  may be extended or retracted relative to the central carriage  44 . It should also be understood that each of the inside track carriage  60  and the outside track carriage  62  may be moved in incremental amounts to vary the distance extended or retracted. 
     Left track mechanism  32  includes a central carriage  90 , an inside track carriage  92  and an outside track carriage  94 . The inside track carriage  92  is extensible and retractable relative to the central carriage  90  by a screw-driven telescoping extender  98 . The telescoping extender  98  includes an electric motor, preferably of the model manufactured by Nook Industies named the 24 volt Actionjac electric cylinder series CC. The telescoping extender  98  is mounted to the central carriage  90  by brackets  100  and  102 . Bracket  100  is mounted on a brace  104  connected to the central carriage  90 . Bracket  102  is mounted near the rear end  106  of inside track carriage  92  with the telescoping extender  98  spanning the brackets  100  and  102 . The outside track carriage  94  similarly includes a telescoping extender  108  mounted by brackets  110  and  112  with bracket  110  mounted to brace  104  and bracket  112  mounted to the forward end  114  of outside track carriage  94 . Each of the telescoping extenders  98  and  108  are moveable independently of each other so that either the inside track carriage  92  or the outside track carriage  94  may be extended or retracted relative to the central carriage  96 . It should also be understood that each of the inside track carriage  92  and the outside track carriage  94  may be moved in incremental amounts to vary the distance extended or retracted. Central carriages  44  and  90  are connected by bracket  114  which extends between left track mechanism  32  and right track mechanism  42 . 
     Now as an example, the right track mechanism  42  of the right shall be described with reference to FIGS. 3 and 6. The central carriage  44  includes the arc gear  36  and the drive gear  40  which connect the central carriage  44  to the base frame. A chain  120  connects sprocket  54  to both the front track drive sprocket  122  and rear track drive sprocket  124  both of which are mounted to the central carriage  44 . 
     The front track drive sprocket  122  is connected to the front track drive gear  126  via a clutch mechanism  128 . The rear track drive sprocket  124  is connected to the rear track drive gear  130  by clutch mechanism  132 . Clutch mechanisms  128  and  132  are preferably Inertial Dynamics Clutch BSL 42 24 volt clutches and permit either the inside track or the outside track to be disengaged from the front track drive sprocket  122  or the rear track drive sprocket  124  for various maneuvers which will be described hereinafter. Each of the inside track mechanism  60  and the outside track mechanism  62  includes a housing  140  and  144  respectively. Housing  140  includes a slot  146  therein to allow movement of the housing  140  relative to the rear track drive sprocket  124 . Housing  144  includes a slot  148  therein to allow movement of housing  144  relative to front track drive sprocket  122 . 
     Front track drive gear  126  engages a chain  150  which drives outside track front pulley sprocket  152  and outside track rear pulley sprocket  154 . Pulley sprockets  152  and  154  turn their respective pulleys  156  and  158  so that outside track belt  160  can rotate to propel the mobility device  10 . Rear track drive gear  130  engages a chain  162  which drives inside track front pulley sprocket  164  and inside track rear pulley sprocket  166 . Pulley sprockets  164  and  166  turn their respective pulleys  168  and  170  so that inside track belt  172  can rotate to propel the mobility device  10 . The inside track housing  140  includes a tensioning wheel  174  rotatably mounted thereon for maintaining tension on the track belt  172 . A tension adjustment screw  176  is mounted on the housing  144  and connected to the tensioning wheel  174  for adjusting the tensioning wheel forwardly and rearwardly to apply proper tension on the inside track belt  172 . The outside track housing  140  includes a tensioning wheel  178  rotatably mounted thereon for maintaining tension on the outside track belt  160 . A tension adjustment screw  180  is mounted on the housing  140  and connected to tensioning wheel  178  for adjusting the tensioning wheel  178  forwardly and rearwardly to apply proper tension to track belt  160 . The inside track housing  144  includes a pair of belt tighteners  182  to assist in maintaining the inside track belt  172  with the ground. Each belt tightener  182  is formed from a triangular piece  184  pivotally mounted to the housing  144  and a pair of wheels  186  mounted thereon for engaging the inside track belt  172 . The outside track housing  140  includes three belt tighteners  182 . The inside track housing  144  is slidably connected to the central carriage  44  by an upper slide rail  190  and a lower slide rail  192 . Similarly, outside track housing  140  is connected to the central carriage by an upper slide rail  194  and a lower slide rail  196 . Each of the slide rails  190 ,  192 ,  194  and  196  are equivalently constructed in that each has a U-shaped member  198  having upper and lower guide bars  200  extending nearly the length of the central carriage  44  with the open side of the U-shaped member extending away from the central carriage  44 . The inside and outside track housings  140  and  144  includes a plurality of rollers  202  mounted to face its respective slide rails  190  and  192 ,  194  and  196  wherein each of the rollers  202  is formed with a groove  204  to retain the rollers  202  in the slide rails  190 ,  192 ,  194  and  196 . The slide rails are preferably of the Rollon Telescopic Rail ASN Series ASN 43 style manufactured by Rollon Corporation of Sparta, N.J. 
     Now referring to FIG. 11, the drive shaft  38  extends into a sleeve  230  in central carriage  90  and is removably connected by a clevis pin  52  and clip  232  extending through holes  234  in sleeve  230 . Bearings  236  support the drive shaft  38  within the central carriage  90 . The bearings are preferably Quality Flanged Sleeve Bearing-Self Lubricating PF12168. Sleeve  230  is supported within central carriage  90  by a pair of fit bearings  237  held by races  238  rigidly joined to both the inside central carriage wall  240  and outside carriage wall  242 . Drive gear  40  is rigidly connected to the sleeve  230 . Outside bearing race  244  is rigidly connected to inside central carriage wall  240 . Bearing race  244  includes a shoulder  246  sized for insertion into a female reception unit  248  to support the central carriage  90  without applying load to the drive shaft  38 . 
     It should be understood that the left side track mechanism  32  is constructed similarly and operates in a similar fashion as the right side track mechanism  42  as has been described. 
     Now referring back to FIG. 2A, the operation of the front drive wheels  22  will be further explained. Front drive wheels  22  include a left wheel  302  and a right wheel  304 . Left wheel  302  is driven by a drive shaft  306  and right wheel  304  is driven by shaft  308 . A sprocket  310  on shaft  306  is driven by a chain  312  extending from drive sprocket  314  mounted on drive shaft  316  extending from clutch  318 . Drive shaft  320  extends from clutch  318  to drive sprocket  322  which is connected by drive chain  324  extending from drive sprocket  326  on motor  328 . Motors  50  and  328  are preferably Micromo Electronics, Inc. PM DC Motor Series. GSN 8070 24 volt DC motors. The transmissions  51  and  329  used with motors  50  and  328  respectively are preferably Indiana Power Transmission System Model ICS Size 50. The right wheel  304  is likewise propelled by driveshaft  308  which includes a sprocket  330  connected by a drive chain  332  to driveshaft  334  extending outwardly from clutch  336 . Driveshaft  338  extends from clutch  336  and includes a drive sprocket  340  connected by a chain  342  to a sprocket  344  at drive motor  50 . Clutches  318  and  336  allow the driving force from the motors  50  and  328  to be selectively disengaged from the wheels  302  and  304 . Clutches  318  and  336  are preferably Inertial Dynamics model BSL42 24 volt clutches. 
     A power source is provided by a 24 volt battery system  400  preferably located under the seat of the mobility device  10 . The various motors and clutches are preferably controlled by a programmable actuation system  402  which may be overridden or reprogrammed by the user. Preferably, an operating console  404  is attached to one arm of the chair so that a seated occupant may operate the mobility device  10 . It should be understood that the while the electrical wiring and circuitry have not been shown, the various electrical components would be electrically connected to the power source  400 . 
     The mobility device  10  is preferably about 30.5 inches wide and about 39.5 inches high when the track mechanisms  32  and  42  are in the down position. The track mechanisms are about 60 inches long in the retracted position and can variably extend up to a length of about 100 inches. However, it should be understood that depending on the use or application of various features of the mobility device  10  and, in particular the track mechanisms  32  and  42 , in other fields such as robotics and industry, the adjustment to the length of the track mechanisms  32  and  42  and other motor driven features may be accomplished alternatively by hydraulic or electrostatic drive mechanisms. Further, the length and width of the track mechanisms  32  and  42  may be altered for particular applications in robotics, industry and exploration. It should also be understood that some or all of the motorized functions of the mobility device  10  could be operated by remote control devices. 
     The operation of the mobility device  10  will now be described with reference to FIGS. 7 through 10. FIG. 7 shows the mobility device with the tracks lowered in the retracted position. FIG. 8 shows the tracks extended for travel over soft terrain or to span a hole or ditch. FIG. 9 shows the mobility device  10  being used to ascend a large (up to 18 inches) step  406  wherein the operation is conducted by using the spur gear  34  to retract the track mechanisms into the upright position, backing up to the step  406  and then extending the outside tracks to push the seat up to a position where the rear wheels  24  can be lowered to engage the top of the step  406  and as the weight of the occupant is over the step the tracks can be rotated to the horizontal position and the rear wheels  24  simultaneously raised and the mobility device  10  can be backed onto the top of the step  406 . It should be understood that this maneuver could be programmed into the mobility device or accomplished by remote control wherein the step is a van or other vehicle. 
     FIG. 10 shows the mobility device  10  used to ascend a staircase  408 . The approach to the staircase  408  would be the same as to a large step, however in this case the tracks would merely climb the steps as if they were a hill. The spur gear  34  and arc gear  36  can be used to adjust the angle of the seat so that the occupant remains in a comfortable position. 
     While this invention has been described as having a preferred design, it is understood that it is capable of further modifications, uses and/or adaptations of the invention following in general the principle of the invention and including such departures from the present disclosure as come within the known or customary practice in the art to which the present invention pertains and as maybe applied to the central features hereinbefore set forth, and fall within the scope of the invention and the limits of the appended claims.