although the invention is described in terms of a specific embodiment , it will be readily apparent to those skilled in this art that various modifications , rearrangements and substitutions can be made without departing from the spirit of the invention . the scope of the invention is defined by the claims appended hereto . now referring to fig1 shown is the preferred embodiment of the instant invention 10 comprising a base frame 12 having five wheels 14 secured to the bottom of said frame 12 . wheels 14 are placed around the perimeter of the base frame 12 and preferably have a central locking and steering ability similar to conventional stretchers wherein they can be fully locked , locked to roll straight ahead , or free wheel . in such an embodiment , two levers , not shown , are mounted on each end of the frame 12 . one lever locks two wheels at that end forcing the united to roll straight ahead for optimum steering . the back wheels pivot free for steering purposes . alternatively , foot operate levers 15 provide simplified engagement of the wheel locks . pivotally mounted to an end 13 of the base frame 12 is a first leg 16 having a shoe plate 18 mounted at a distal end 19 of the leg 16 . structure 20 provides a support housing for electric motors used for operating the components as well as an upper articulating point 21 for the legs 16 and 16a . a first strut 22 is pivotally coupled to said upper articulating point 21 and to the illustrated leg 16 at lower pivot point 26 . the strut 22 utilizes a centrally disposed over - center hinge 28 which folds inward so as to allow the leg 16 into a vertical stance for purposes of storage . to retract the legs , motor 50 is mechanically linked to the legs 16 and 16a and boom motor 52 provides retraction of the boom 34 in a similar manner . a hoist motor 54 provides the lifting and lowering of the hook 58 , and a swing motor 56 is used to modulate the angular arc of the boom 34 . the support frame 20 includes hand grips 30 placed along an upper rail 31 providing an operator with a predetermined position for moving of the lifting device . the handgrips 30 can be accompanied by hand brakes , not shown , for use in preventing wheel 14 rotation . in such an embodiment , the operator can prevent movement of the unit by simply squeezing a hand brake in a similar fashion as a brake used on a bicycle . once stopped , the apparatus can be locked in position through the use of the aforementioned wheel locks 15 . an alternate embodiment is to use hand grips that apply constant braking force so as to require the operator to maintain their hands on the apparatus during transportation . this is especially useful in those circumstances where a ramp is encountered during transportation . in such an embodiment , should a unit free roll down a ramp the brakes will engage to bring the unit to a stop . boom head 32 is supported by the frame 20 and is shown in its extended position . extension of the boom 34 is made possible by an electric motor driven linear actuator 66 which extends crutch 36 which is coupled to the boom 34 by upper pivot point 38 and lower pivot point 40 . the centrally disposed hinge 42 is forced over - center by the linear actuator causing said hinge to lock in a fixed position . storage of the boom occurs by folding of the boom 34 downward by allowing the boom 34 to fold within the confines of the frame 20 by reversal of the above steps . similarly , the legs 16 are folded upward by the inward movement of the strut hinge 28 so as to provide a compact unit that stores in a small closet and can be maneuvered through doorways . an additional cable runs parallel to strut 22 and when said cable is pulled in by the leg motor , after the solenoid releases the over - center hinge , the leg folds to the near vertical position . now referring to fig2 shown is the lifting device 10 in a retracted position wherein the base frame 12 provides the footprint for the structure 20 made portable by the wheels 14 . the boom 34 is shown in its downwardly folded position while the legs 16 are shown in an upwardly folded position , all within the confines of the support structure 20 . as depicted by this view , the crutch 36 is hinged 42 at a center point allowing the boom 34 to form a near vertical position thus eliminating the space necessary for a conventional hoisting unit and preventing the possibility of harm to an operator who inattentively walks into a fully extended boom . the over - center hinge is pulled from its locked state by use of a boom motor 52 which pulls the crutch cable 64 , see fig1 causing the crutch 36 to fold in the center . linear actuator 66 operates to place the boom 34 in an extended or upright position . similarly , the legs 16 fold upright to maintain the unit &# 39 ; s small storage footprint while further eliminating an unguarded leg extension common among those units in the industry , thus eliminating the possibility of injury to tripping an individual attempting to step over an extended support leg . the strut 22 is hinged 28 at a center point allowing the leg 16 to form a near vertical position . the over - center hinge is pulled from its locked state by use of a leg motor 50 which pulls the strut cable 61 , see fig1 causing the strut 22 to fold in the center . gravity operates to bias the leg 16 into the extended position . a spring , not shown , can be incorporated in the leg to facilitate the biasing of the leg in an extended position . fig3 sets forth a top view of the instant device 10 in a fully extended form illustrating the wide u - shaped structure . leg 16a operates in conjunction with leg 16 providing enhanced stability during operation . each leg is raised and lowered by use of the same electric leg motor 50 so to operate in unison at all times . the leg support position is made possible wherein strut 22 and 22a is in a fully extended position allowing the strut hinges 28 and 28a to be locked in position forcing the shoe skid 18 and 18a to press against the floor . the stance provides stability for the boom 34 as it extends outward over the patient to be lifted . in operation , the device 10 is moved into position so that the legs and boom 34 can extend without interference . as the unit is electrically powered , an ac cord is provided for insertion into an available wall socket to power the electrical motors , namely , the leg hoist 50 , the hoist motor 52 , the swing motor 54 , and the boom motor linear actuator 66 . control of the system is performed by a control panel positioned in a hand held control ball fabricated from a three inch thick solid resilient ball as described later in this specification . placement of the leg and boom components in an operating position is accomplished by depressing a button on the control panel which simultaneously operates the leg motor 50 and boom motor linear actuator 66 allowing the legs 16 & amp ; 16a and the boom 34 to extend into their operating position . the operator may stop the extension procedure at any time should the legs or boom encounter interference . led lamps are provided to represent the position of the legs and boom . the lamps will change from a blinking red color to a continuous green color when sensors , not shown , confirm a positive lock in the extended position similar to the indicators used with airplane landing gear . the boom 34 has an angular sweep d 1 between legs 16 and 16a allowing the operator to pick up a patient at one position and transport the patient to a second position . boom swing angle is approximately forty degrees with a twenty degree tolerance . the reach of the boom is sixty inches , slightly less than the preferred leg reach of approximately eighty inches . in operation it is recommended that a patient is placed upon a support sling wherein the boom 34 is swung over the patient in a lifting bar properly positioned over the support sling . this will minimize any swinging tendency as the support sling and patient is pulled upward . a hook 58 is located at the end of the boom 34 . during this position the device 10 can be rolled slightly so as to facilitate correct positioning . once the device 10 is properly located the wheels can be locked by use of the foot lever 15 . a frame mounted lever , not shown , can be used to lock the wheels in a position allowing straight roll . using the control panel a button is provided to lower the hook 58 until the lifting assembly is attached . raising the patient is performed by depressing a button on the control panel allowing upward movement so as the patient and sling are above both departure and arrival surfaces . the patient can then be swung from the departure surface to the arrival surface by provision of a right and left directional control button allowing movement of the boom 34 . the patient is then unhooked from the hook 58 and the device 10 is positioned such that the legs 16 and boom 34 can be retracted without interference . when the unit is to be transported or stored , a control button is provided so as to retract the legs and boom , the movement can be halted at any point if necessary . during the retraction the led &# 39 ; s representing the legs and the boom will blink red until sensors ( not shown ) detect a positive latch for storage . at that point , the led &# 39 ; s will stop blinking and be in a continuous red position . the device 10 can then be turned off and the ac cord unplugged and coiled for storage with the device 10 . referring to fig4 the boom 34 is mounted on a rotatable boom head 32 that provides a pivot point 62 for one end of the boom 34 that is used in the retracted state . in particular the pivot point 62 allows the boom 34 to fold downward in a retracted position . the hinge 42 is an over - center hinge causing the crutch to lock into position . collapsing of the boom requires that the hinge 42 is pulled off center by the cable 64 by a solenoid , not shown . the rotatable sleeve is manufactured from light weight aluminum having a five and a half inch diameter which is rotatably coupled to the frame 20 by a rotatable bearing 74 located at the bottom of the head 32 to allow rotation about a predetermined angle . the frame 20 incorporates a support post 76 which is placed on the inner side surface of the pipe 72 having a plurality of inwardly facing centering components which are plastic guides 78 maintaining a fixed distance between the head pipe 72 and the support post 76 . fig5 illustrates a first side of the control system in its preferred embodiment comprising a hand held control ball 90 fabricated from a three inch diameter solid resilient ball . a control panel 91 is mounted in a recess 93 inside the ball 90 wherein a coiled cord , not shown , suspends the ball 90 at a convenient height for the operator to use . the rubber portion 95 of the ball 90 protects both the key pad 91 from damage and accidental button activation should the ball 90 swing free . depressing of the control button 92 labeled &# 34 ; e &# 34 ; causes the legs and boom to extend so that the leg and boom actuator motor allow their respective latches to extend and lock into position . the leg motor is recommended to be geared to extend the legs at a linear speed at approximately 1 ( one ) inch per second . optical sensors , such as honeywell ultra thin reflective sensors are utilized to confirm that the legs have extended and locked before the hoist can be operated . the reflective sensors each contain an optical infrared emitting diode and a detector mounted in side by side converging optical axis . the detector responds to the radiant power only when a reflector object passes within the field of view . similarly , the boom extends allowing the over - center hinge on the crutch to lock into position wherein the aforementioned optical sensor confirms the fully locked position by lighting of the led lights for the legs 96 , 98 and the boom 100 . during retraction the retraction button 94 is depressed wherein the legs and the boom return to their retracted position and the led lights 96 , 98 , and 100 illuminate to indicate the stored position . the back side of the control panel shown in fig6 causes the hoist to move in the upward position by depressing of directional positioning switches . depressing of an up switch 102 will operate the hoist motor for lifting of the hook . depressing of a down switch 104 will operate the hoist motor for lowering of the hook . movement of the boom to the left is accomplished by depressing the left switch 106 and movement of the hoist to the right is accomplished by depressing of the right switch 108 . lights are provided for indication of the leg 110 lock , boom 112 lock and wheel 114 lock . the hoist cable and pulleys should be rated for at least one - thousand pounds with a preferred linear cable speed of about 1 ( one ) inch per second . the hoist motor should be able to drive the cable reel via a worm gear thus the weight on the cable cannot cause the cable reel to rotate . it is to be understood that while i have illustrated and described certain forms of my invention , it is not to be limited to the specific forms or arrangement of parts herein describe and shown . it will be apparent to those skilled in the art that various changes may be made without departing from the scope of the invention and the invention is not to be considered limited to what is shown in the drawings and described in the specification .
a portable lifting apparatus for lifting and transferring of patients for use in combination with a sling or the like support . the apparatus is stored in a retracted state by placement of supporting legs and the lifting boom in a folded position . the apparatus can be placed into an operating position in less than two minutes by extension of the support legs and lifting boom which are then locked into position by the use of over - center latches used on leg struts and a boom crutch . extension is verified by the use of led indicator lights located on a control panel providing operational sequences from a single location . separate motors are provided for placement of the legs and boom as well a hoist motor for operating a hoist and a swing motor for angular placement of the boom unit . in a retracted state the apparatus can be stored in a small area such as a closet having a footprint no larger than the size of the base frame . portability is provided by lockable wheels positioned beneath the frame which can be used in conjunction with hand brakes for braking purposes .