Abstract:
A method and apparatus for lifting a patient is disclosed to include a base with wheels on the back side and casters on the front side; a pair of extendable legs extended or withdrawn from the frontal side of the base to maintain balance when lifting a patient; vertical masts connected to a three-prong hanger; three durable cables used with a sling assembly to lift the patient; a foldable chair provides temporary rest for the patient on the patient lift; and a control panel having a micro-controller for remotely controlling the patient lift.

Description:
CLAIM OF PRIORITY 
       [0001]    This application is a continuation application of application Ser. No. 14/523,887, entitled “Method for an Automatic Patient Lift”, filed on Oct. 25, 2014, which is a divisional application of application Ser. No. 14/229,829, filed Jan. 25, 2014, entitled, “Method and Apparatus for an Automatic Patient Lift”. The patent applications identified above are incorporated here by reference in its entirety to provide continuity of disclosure. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates generally to the field of medical devices. More specifically, the present invention relates to transporting and lifting a patient. 
       BACKGROUND ART 
       [0003]    Whether at home or in a hospital, patients or elderlies often need to be transported safely from one place to another place. It is dangerous for post-surgery patients to move by themselves. In other situations, the elderly need assistance to transfer from bed to chair in a different room or to a toilet. 
         [0004]    Traditionally, conventional patient lifts do not include enough function to adapt to different situations when a patient needs to be transported. Due to their feeble health conditions, mismanaging a particular situation can be dangerous or often found fatal to the patients or the elderly. Particular situations may include transporting a patient from a recumbent position to a seated position at a different location. The destination can be far away or can be to a next bed. Another situation occurs when the patient is transported changing from a seated position to a recumbent position. Yet another situation occurs when transporting a patient to a toilet. Conventional patient lift devices cannot provide sufficient functions to assist medical users to help patients sit in a correct direction. 
         [0005]    Yet another problem of the conventional patient lifts is that they are not equipped with appropriate motors designed to perform a specific task. Conventional patient lifts do have motors but these motors are not designed to operate in a specific situation to eliminate physical damage to the patients. 
         [0006]    Yet another problem of the conventional patient lifts is that their sling assemblies are not flexible to change patient posture from recumbent to seated or vice versa. Conventional patient lift still need a nurse or medical assistant to lift a patient when changing from recumbent to seated. This can create a lot of stress to the patient. 
         [0007]    And yet another problem with conventional patient lifts is that the conventional patient lift does not include a temporary support chair for a patient to rest when transport in a long distance. This is true for the elderly. They can sit and rest on the chair but it is physically taxing to their health when they are transported on conventional sling assembly. 
         [0008]    Therefore what is needed is a patient lift that can overcome the above described problems. 
       SUMMARY OF THE INVENTION 
       [0009]    Accordingly, an objective of the present invention is to provide an automatic patient lift which provides solutions to the problems described above. Thus, a method and apparatus for lifting a patient is disclosed to include a base with wheels on the back side and caster wheels on the front side; a pair of extendable legs extended or withdrawn from the frontal side of the base to maintain balance when lifting a patient; vertical masts connected to a three-prong hanger; three durable cables used with a sling assembly to lift the patient; a foldable chair provides temporary rest for the patient on the patient lift; and a control panel having a micro-controller for remotely controlling the patient lift. 
         [0010]    These and other advantages of the present invention will no doubt become obvious to those of ordinary skill in the art after having read the following detailed description of the preferred embodiments, which are illustrated in the various drawing Figures. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
           [0012]      FIG. 1  is a diagram illustrating a patient lift in accordance with an embodiment of the present invention; 
           [0013]      FIG. 2  is a diagram illustrating a patient lift when it is in the lean forward state to receive a patient in accordance with an embodiment of the present invention; 
           [0014]      FIG. 3  is a diagram illustrating the components inside the base of the patient lift in accordance with an embodiment of the present invention; 
           [0015]      FIG. 4  is a diagram illustrating a method for lifting a patient in accordance with an embodiment of the present invention; 
           [0016]      FIG. 5 . is a diagram illustrating all the command buttons located on a control panel used to control the patient lift in accordance with an embodiment of the present invention; 
           [0017]      FIG. 6  is a flow chart illustrating a software program, stored in a non-transitory computer storage of a programmable micro-controller, when executed the software program performs four basic functions to control the patient lift in accordance with an embodiment of the present invention; 
           [0018]      FIG. 7  is a flow chart illustrating the first basic function (instruction command) to move the patient from a recumbent position to another recumbent position in accordance with an embodiment of the present invention; 
           [0019]      FIG. 8  is a flow chart illustrating the second basic function (instruction command) to move the patient from a recumbent position to a seated position in accordance with an embodiment of the present invention; 
           [0020]      FIG. 9  is a flow chart illustrating the third basic function (instruction command) to move the patient from a seated position to a recumbent position in accordance with an embodiment of the present invention; and 
           [0021]      FIG. 10  is a flow chart illustrating the fourth basic function (instruction command) to move the patient from a seated position to another seated position in accordance with an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0022]    Reference will now be made in detail to the preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. While the invention will be described in conjunction with the preferred embodiments, it will be understood that they are not intended to limit the invention to these embodiments. On the contrary, the invention is intended to cover alternatives, modifications and equivalents, which may be included within the spirit and scope of the invention as defined by the appended claims. Furthermore, in the following detailed description of the present invention, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be obvious to one of ordinary skill in the art that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures, components, and circuits have not been described in detail so as not to unnecessarily obscure aspects of the present invention. 
         [0023]    One embodiment of the invention is now described with reference to  FIGS. 1 to 3 .  FIG. 1  shows one embodiment of a patient lift  100 . The patient lift  100  includes a base  101  having a front side and a back side. The base  101  is mounted on a first wheel  101 F 1 , a second wheel  101 F 2  (not seen in  FIG. 1 ; please refer to  FIG. 3 ), a third wheel  103 B 1 , and a fourth wheel  103 B 2  (not seen in  FIG. 1 ; see  FIG. 3 ). In one embodiment, third wheel  103 B 1  is mechanically connected to the backside of base  101  and electrically connected to a first motor  311  (not shown in  FIG. 1 ; please see  FIG. 3 ) whereas fourth wheel  103 B 2  is connected to a second motor  312 . In the embodiment shown in  FIG. 1 , first wheel  101 F 1  and second wheel  101 F 2  are caster wheels. They are configured to swivel and change directions as base  101  is moving. 
         [0024]    Continuing with  FIG. 1 , a first extendable leg  105 A and a second extendable leg  105 B are mechanically connected to base  101 . First extendable leg  105 A and said second extendable leg  105 B configured to extend or withdraw from the front side of base  101 . A third motor  313  (not shown in  FIG. 1  but can be seen in  FIG. 3 ) is mechanically connected to first extendable leg  105 A and second extendable leg  105 B via a glider  315  and a spring  316  (please see  FIG. 3 ) in order to cause first extendable leg  105 A and second extendable leg  105 B extend outward or withdraw from the front side of base  101  through openings as shown in  FIG. 1 . In addition, a fifth wheel  104 PF 1  is mechanically connected to first extendable leg  105 A and a sixth wheel  104 PF 2  is mechanically connected to second extendable leg  105 B respectively. In one embodiment, fifth wheel  104 PF 1  and sixth wheel  104 PF 2  are caster wheels similar to first wheel  101 F 1  and second wheel  101 F 2 . 
         [0025]    Referring again to  FIG. 1 , a first mast  131  and a second mast  132  are mechanically connected to the back side of base  101 . In one embodiment, the lengths of first mast  131  and second mast  131  are designed to be adjusted so that patient lift  100  can be folded. On top of first mast  131  and second mass  132 , a lever  133  is extended forward toward the front side of base  101 . There, a three-prong hanger having a first prong  152 , a second prong  153 , and a third prong  154  mechanically connected to lever  133 . A rotator  155  interconnects lever  133  and three-prong hanger  152 - 154  so that three-prong hanger  152 - 154  can rotate freely in clockwise and counter-clockwise around a vertical axis. Rotator  155  is designed so that a medical assistant can help the patient to face in a correct direction, especially when the patient needs to sit down a chair or a toilet bowl. A fourth motor  151  is connected to rotator and operable to cause rotator  155  to rotate. 
         [0026]    Continuing with  FIG. 1 , a first cable  141 , a second cable  142 , and a third cable  143  are connected to each prong of said three-prong hanger  152 - 154  respectively. In one embodiment, first cable  141 , second cable  142  configured to operate simultaneously and third cable  143  are configured to extend or withdraw independently of first cable  141  and second cable  142 . A sling assembly  201  (not shown in  FIG. 1 , please refer to  FIG. 2 ) having three different holes are configured to connect to first cable  141 , second cable  142 , and third cable  143 . In one embodiment, said third cable  143  is connected to sling assembly  201  at a location between the patient&#39;s two legs, to first cable  141  at the patient&#39;s left shoulder, and to second cable  142  at the patient&#39;s right shoulder. 
         [0027]    Next, a foldable chair  120  is mechanically connected to first mast  131  and second mast  133 . In one embodiment, foldable chair  120  has a support portion  121  configured to support a patient, and a back portion  122 . A left hand rest  123  and a right hand rest  124  are connected to support portion  121 . 
         [0028]    Continuing again with  FIG. 1 , a removable fifth motor  106  is mechanically connected between first mast  131  and base  101 . In one embodiment, one end of removable fifth motor  106  is fixedly connected to first mast  131  and support portion  121  of foldable chair  120 . The distal end of removable fifth motor  106  can be removed so that patient lift  100  can be folded up. 
         [0029]    Next, a first pulley  161  is mechanically coupled to first cable  141  and second cable  142 . A sixth motor  181  is mechanically connected to first pulley  161 . Sixth motor  181  is designed to control first cable  141  and second cable  142  simultaneously. On the other hand, second pulley  162  houses to third cable  143 . A seventh motor  182  is mechanically connected to second pulley  162 , operable to control said third cable  143 . 
         [0030]    Still referring to  FIG. 1 , a handle  110  connected to the rear end of base  101 . On top of handle  110 , a control panel  111  is designed to control the operations of first motor  311 , second motor  312 , third motor  313 , fourth motor  151 , fifth motor  106 , sixth motor  181 , and seventh motor  182 . 
         [0031]    Finally, a switch box  170  is coupled to second wheel  103 B 1  and fourth wheel  103 B 2 . Switch box  170  is configured to decouple third wheel  103 B 1  and fourth wheel  103 B 2  from first motor  311  and second motor  312  so that patient lift  100  can be pushed by the medical assistant. 
         [0032]    In one embodiment, base  101  has a width of 0.75 meters, a maximum length when first extendable leg  105 A and second extendable leg  105 B are fully extended is 1.6 meters. Base  101  has a minimum length of 1.2 meters when first extendable leg  105 A and second extendable leg  105 B are fully withdrawn. The height of base  101  including first mast  131  and second mast  132  is 2.25 meters calculated for average human heights between 1.7 meters to 1.9 meters. 
         [0033]    The following table lists all the motors described above: 
         [0000]    
       
         
               
               
               
               
             
           
               
                   
               
               
                 Motor 
                 Function 
                 Power 
                 Speed 
               
               
                   
               
             
             
               
                 First motor 311 
                 Control third 
                 106.57 W  
                 200 rounds/minutes 
               
               
                 and Second Motor 
                 wheel 131B 
               
               
                 312 
                 and fourth 
               
               
                   
                 wheel 132B 
               
               
                 Third motor 313 
                 Control 
                   30 W 
                 300 rounds/minutes 
               
               
                   
                 extendable 
               
               
                   
                 legs 104PF1 
               
               
                   
                 and 104PF2 
               
               
                 Fourth motor 151 
                 Control rotator 
                   30 w 
                  12 rounds/minutes 
               
               
                   
                 155 and three- 
               
               
                   
                 prong hanger 
               
               
                   
                 152-154 
               
               
                 Fifth motor 106 
                 Control first 
                   400 W 
                 N/A 
               
               
                   
                 mast 131 and 
               
               
                   
                 second mast 
               
               
                   
                 132 
               
               
                 Sixth motor 181 
                 Control first 
                 186.5 W 
                 21 rounds/minute 
               
               
                   
                 cable 141 and 
               
               
                   
                 second cable 
               
               
                   
                 142 
               
               
                 Seventh motor 
                 Control third 
                 93.25 W 
                 20 rounds/minute 
               
               
                 182 
                 cable 143 
               
               
                   
               
             
          
         
       
     
         [0034]    Now referring to  FIG. 2 , patient lift  100  is controlled by control panel  111  to lean forward to pick up a patient. The detailed operation of control panel  111  and patient lift  100  will be discussed later.  FIG. 2  also illustrates mast assembly  201  on which a patient is lifted and transported to either foldable chair  120  or to a nearby location. 
         [0035]    Next referring to  FIG. 3 ,  FIG. 3  shows the view of patient lift  100  from the bottom perspective. From this view, first motor  311  and second motor  312  are shown. Furthermore, slider  315  and spring to extend or withdraw first extendable leg  105 A and second extendable leg  105 B can also be illustrated. 
         [0036]    Now referring to  FIG. 4 , a method  400  for operating patient lift  100  described above is illustrated. Basically, control panel  111  has a micro-controller (not shown) programmed to control first motor  311 , second motor  312 , third motor  313 , fourth motor  151 , fifth motor  106 , sixth motor  181 , and seventh motor  182  in accordance with predetermined situations when lifting a patient. 
         [0037]    At step  401 , lift device  100  is reset to its initial position. That is a straight up position perpendicular to the ground. More specifically, if the x-z surface is parallel to the ground, at the reset position, patient lift  100  is coincide to the y-axis as illustrated in  FIG. 1 . Step  401  is performed by releasing fifth motor  106  so as it pushes first mast  131  and second mast  132  to a vertical direction perpendicular to the ground. 
         [0038]    Then at step  402 , patient lift  100  is moved to where a patient in need of transport. Step  402  is realized by using control panel  111  to move forward, backward, turn left, turn right to the patient&#39;s location. 
         [0039]    At step  403 , a user or a medical assistant selects at least one command buttons on control panel  111 . 
         [0040]    At step  404 , if a completion button is entered, the command selected at step  403  is final and micro-controller or control panel perform steps programmed in that command. Otherwise, micro-controller waits for another command button to be pressed. In other words, according to the present invention, a command button is only performed when it receives the completion command. 
         [0041]    Next, at step  405 , a second command is selected. 
         [0042]    At step  406 , after the completion command is received, steps pre-programmed in one or two commands are performed. 
         [0043]    At step  407 , patient lift  100  is bent down to receive a patient. This step is carried out by fifth motor  106  reduces its length, causing first mast  131  and second mast  132  to lean forward. At the same time, foldable chair  120  is folded up. This step  407  is illustrated in  FIG. 2 . 
         [0044]    Next, at step  408 , first extendable leg  105 A and second extendable leg  105 B are pushed forward by third motor  313  so as patient lift  100  will not fall forward when lifting up a patient. 
         [0045]    At step  409 , a user or medical assistant uses first cable  141 , second cable  142 , and third cable  143  to connect to sling assembly  201 . More particularly, first cable  141  and second cable  142  are used on the patient&#39;s shoulder. Third cable  143  is used to connect to sling assembly  201  in the area between patient&#39;s legs. 
         [0046]    At step  410 , micro-controller on control panel  111  controls first cable  141 , second cable  142 , and third cable  143  accordingly to each situation specified by selected commands described in step  403  to step  404 . In more details, when the patient&#39;s initial position is recumbent, first cable  141 , second cable  142 , and third cable  143  are controlled simultaneously to lift patient so that the recumbent posture is achieved. On the other hand, when the patient needs to change from recumbent to seated, only first cable  141  and second cable  142  are pulled up so as to cause the patient to sit up. 
         [0047]    Finally, at step  411 , the patient is transferred to a final destination. 
         [0048]    Now, referring to  FIG. 5 , control panel  111  or remote control  500  is described in connection with operation of patient lift  100  described in  FIG. 1 - FIG. 3  above. 
         [0049]    Structurally, remote control  500  includes a first command  501  when said user switches from an automatic mode to a manual mode. As discussed above, when problem occurs with first motor  311  and second motor  312 , causing patient lift  100  to be immobile, first command button  501  is pressed to allow patient lift  100  to be operated manually. 
         [0050]    Next, a situational command area  510  groups command buttons related to different situations in which a patient is transport. Specifically, a second command button  511  is selected when a user or medical assistant intends to lift a patient from a recumbent position to a seated position on foldable chair  120  of patient lift  100 . A third command button  512  is selected when the user lifts patient from foldable chair  120  of patient lift  100  to a recumbent position in a different location. A completion command button (or “OK button)  515  is selected when a command selected by the user is final and micro-controller  111  performs the selected command(s). Otherwise, micro-controller  111  waits for another command to be entered, wherein when two command buttons are entered and then completion command button  515  is pressed, micro-controller  111  performs the two selected command buttons. 
         [0051]    Next, continuing with  FIG. 5 , a fourth command button  513  is selected when the user lifts a patient from a seated position to foldable chair  120  on patient lift  100 . A fifth command button  514  is selected when the user lifts a patient from foldable chair  120  of patient lift  100  to another seated position in a different location. A sixth command button  530  is selected when the user controls the movement of patient lift  100  including increasing, decreasing the speed of patient lift  100 , moving forward, turning left, turning right, and reversing of patient lift  100 . In one embodiment, sixth command button  530  can be a joystick. In another embodiment, sixth command button  530  can be configured to include forward arrow, backward arrow, left arrow, and right arrow. 
         [0052]    Continuing again with  FIG. 5 , a command group  520  is used when the user wants to rotate a patient by rotator  155 . Command group  520  includes seventh command button  521  for is selected when the user rotates rotator  155  in a counter-clockwise direction. Finally, an eighth command button  522  is selected when the user rotates rotator  155  in a counter direction. 
         [0053]    In operation, upon selecting the second command  511  and completion command button  515  are selected, micro-controller  111  causes said sixth motor  181  and seventh motor  182  to operate first cable  141 , second cable  142 , and third cable  143  simultaneously so that patient is assisted to sit on foldable chair  120  of patient lift  100 . 
         [0054]    Next, when second command button  511  and third command button  512  are selected and then completion command button  515  are selected, micro-processor  111  is operable to maintain the lengths of first cable  141 , second cable  142 , and third cable  143 . Finally, micro-processor  111  transfers patient from seated position to a recumbent position in a different location. 
         [0055]    In another occasion, when completion command button  515  is selected after fourth command  513  is selected, micro-controller  111  causes sixth motor to maintain the lengths of first cable  141 , second cable  142 , and third cable  143  so that patient is transferred from a seated position to foldable chair  120  of patient lift  100 . 
         [0056]    In another situation, when fourth command button  513  and fifth command button  514  are selected, and then completion command button  515  is selected afterward, micro-controller  111  causes sixth motor  181  to cause to maintain the lengths of first cable  141 , second cable  142 , and third cable  143  so that patient is transferred to another seated position at a different location. 
         [0057]    Continuing with the operation of patient lift  100  as described in  FIG. 5 , when second command  511  and fifth command  514  are selected together and then completion command  515  is selected, micro-controller  111  causes said sixth motor  181  and seventh motor  122  to operate first cable  141 , second cable  142 , and third cable  143  simultaneously. Then patient is transferred to another seated position at a different location. 
         [0058]    Finally, when fourth command  513  and third command button  512  are selected together and completion command button  515  is selected, micro-controller  111  causes sixth motor  181  to operate first cable  141  and said second cable  142  together and seventh motor  182  to maintain third cable  143  and then to transfer patient to a recumbent position at a different location. 
         [0059]    The foregoing description details certain embodiments of the invention. It will be appreciated, however, that no matter how detailed the foregoing appears in text, the invention can be practiced in many ways. As is also stated above, it should be noted that the use of particular terminology when describing certain features or aspects of the invention should not be taken to imply that the terminology is being re-defined herein to be restricted to including any specific characteristics of the features or aspects of the invention with which that terminology is associated. The scope of the invention should therefore be construed in accordance with the appended claims and any equivalents thereof.