1. Technical Field
This invention relates to a portable patient lift apparatus for use by humans. More specifically, this invention relates to a portable lifting apparatus for assisting in lifting obese individuals in and out of a hospital bed or other locations and then transporting them to a different location.
Nursing staffs have the highest incidences of work-relate back problems of any occupation. The incidence rate continues to climb. Work-related musculoskeletal disorders (MSDs) account for a major portion of the cost of work-related injuries in the United States. A contributing factor is the fact that the American population has become one of the most overweight in the world. Nearly 97 million American adults are overweight. Of the 97 million overweight American Adults, it is estimated that 4 million are severely obese [Body Mass Index {BMI}>35 and 1.5 million [BMI>40] are morbidly obese.
With these rising numbers of severely and morbidly obese individuals come numerous complications relating to medical treatment. Besides the cost issue, healthcare providers must consider the daunting safety implications for both the patient and caregiver. One specific problem lies in simply providing a means for these patients to be able to rise or sit on the hospital bed or other locations without the risk of harm to the patient and/or the caregiver performing this task.
The movement of bariatric patients (a medical term derived from the Greek word “baros” meaning weight) produces special challenges to health care professionals. Internationally, bariatric patient is defined as an individual that has a BMI>30. Many studies have shown that health care workers are at the greatest risk for musculoskeletal injuries when dealing with bariatric patients, particularly in the sit-to-stand transfer mode. The best way to ensure safe patient handling is through the use of specialized mechanical equipment that is designed to meet the size and weight requirements of the bariatric patient.
One of the main benefits of the apparatus is that it requires only a single person to perform the sit-to-stand transfer function of the bariatric patient, which in turn will reduce the resources expended to perform this task.
2. Description of the Prior Art
There are many types of mechanical lift mechanisms on the market for bariatric patient lifting. Some of the present designs are inherently unstable in nature because of their basic design philosophy. Others are extremely large and bulky and can not be used effectively in the bariatric patient's room. In others the inability to transfer bariatric patients from certain types of wheelchairs or other assistive items because they contain certain obstacles is inherent to their design. One of the functions of the proposed device is to provide controlled unassisted lifting movement for the user. The inability of some bariatric patients to provide any self induced lifting ability in a normal manner without the chance of a fall is a major limiting feature of present mechanical lift device designs.
There are at least 6 types of mechanical lift mechanisms on the market today. They range from he following: 1) Powered Hospital bed that converts to a chair (known as a Total Care Bed System®); 2) Permanently mounted powered ceiling system; 3) Permanently mounted powered wall system; 4) A mobile powered sling lift mechanical device; 5) Mobile powered lift/stand mechanical device; and 6) Powered Standing Frame mechanical device. However, each of these types has at least one major deficiency.
The majority of the lift systems are some type of a sling mechanism. The sling is subject to several types of failures. The FDA has reported that there have been more than 50 deaths and over 500 patients have been seriously hurt because of failure of sling type lift systems. The following is summation of failures that caused death or severe injuries: 1) The patient fell to the floor when the strap that attaches the sling to the lifting frame failed; 2) The patient fell to the floor when the gravity-activated locking clip which holds the strap to the lifting frame failed; 3) The patient fell to the floor because of the patient's movement within the sling allowed the sling to slip out of the spreader bar; 4) The patient fell to the floor because the sling that was used was too large for the patient; 5) The patient fell because the lifting frame failed because of excessive load; and 6) The patient fell to the floor because the lifting mechanism the raises and lowers the jib failed resulting the sudden drop of the jib.
The ceiling lift is one of the newest types of patient lift systems and has been available in the United States for several 5 years. The main disadvantages associated with the ceiling lift system are the installation of overhead tracks and failure and/or stoppage of the electric drive motor unit. A track must be procured and installed in each room that requires patient transfer capabilities. Room to room transfer with the ceiling lift system will be difficult. One problem is the removal of doorway headers and replacing them with some type of header assembly that will let the ceiling lift system pass from room to room but still provide privacy to the patient. Also load conditions on the ceiling and walls must be considered in the installation of this type of patient lifter.
The wall mounted lift system is similar to the ceiling lift system except the lifting motor unit is attached to a wall mounted jib rather than a track. The main disadvantages associated with the wall mounted lift system are the limited transfer range and failure and/or stoppage of the electric drive motor unit.
The powered mobile sling lift system also known as the Hoyer style lifter is the most commonly used. The main disadvantages associated with the powered mobile sling lift system are the ability of the caregiver to maneuver the lifter once a patient is loaded into the sling, failure jib mechanism and/or failure and/or stoppage of the electric lift motor unit.
A major problem with the use of any sling lift system is the fact that the patient requires a lift team (two or more caregivers who are training in proper lifting techniques) to move the bariatric patient on to and off the sling. Another problem is to provide the necessary force to move the lift mechanism to the desired location. To instruct the patient to remain motionless while being lifted to reduce the chance of lift mechanism instability is another concern.
The powered mobile sit/stand system differs from the three previous mentioned lift systems in the fact that the patient must be cognitive and provide some cooperative effort in the lifting task. The patient must possess some muscle tone in at least one lower limb, trunk and at least one upper limb. The main disadvantages associated with the mobile sit/stand system are the clearance required for the legs and/or maneuver the lifter once the patient is loaded on the lifter.
The powered standing frame system is similar to the mobile sit/stand system but it provides for a work area so that the patient can perform various tasks while standing without the fear of falling. The main disadvantages associated with the powered standing frame system are the ability of the caregiver to maneuver the system once a patient is standing in the device, failure of the control mechanism and/or failure and/or stoppage of the electric lift motor unit.
As mentioned above the Total Care Bed System® is not a lifting mechanism per se, it only positions the patient from a prone to sitting position but does not lift the patient out of the bed and transfer the patient to a new location.
Presently there are many techniques for providing maximum structural capabilities to patient lifting system designs. These patient lifting system designs have inherent deficiencies because of limited stability, mobility, space and ruggedness required in their use. The inability to acquire stress analysis data from these patient lifting system designs in a natural surrounding introduces some distortion in the data acquired and its interpretation of the data as a result of their inherent designs. In some cases it requires the tester to use cumbersome hardware and/or testing harness(s) in order to obtain the desired data for evaluation.
One of the unique features of this patient lifting system is that it allows the patient to maintain or increase muscle tone, range of motion and possibly optimize blood flow in the their extremities.
The apparatus uses a specialized drive wheel set to negotiate around various restrictive areas. The apparatus has steering and drive wheels, which are microprocessor controlled. In the storage mode the apparatus collapses into small mobile module that stands approximately 3 feet tall and base circumference approximately of 2 feet in diameter. When fully operational the device has approximately a maximum of 7 feet in height, appendages that have approximately a maximum reach of 4 feet and a base radius of approximately 3½ feet. The entire apparatus is motorized, which can operate on internal power source or external power. The caregiver operates the entire configuration by means of a remote controller, which is connected to microprocessor via a wireless datalink. This includes transformation from storage to operational mode, movement of the appendages, and movement of the device to various locations. The caregiver will determine direction, speed and location of the various appendages so as to lift the patient from one location and transport the patient to a different location by sending the appropriate control signal(s) to the various drive units that manipulate the various appendages and/or drive wheel. Each power drive unit consists primarily of a drive motor, gear reduction unit, coupling mechanisms and electronic control module. Steering is accomplished by control signals generated by the caregiver to drive a reversible DC brushless motor that rotates the rear drive wheel unit to the desired alignment direction. Also, a built-in power source such as lithium, Silver-Zinc, Alkali-Zinc batteries or some other power source [such as fuel cell(s), etc.] which provide the power required for each control module and various DC brushless motors. Power drive units could also be operated by means of hydraulics or similar power source rather than DC brushless motors except for the drive wheel portion.
The overall apparatus is designed for ease of use, transport and storage. In designing stability into the apparatus, overall effectiveness and safety was not compromised. The stability of the apparatus is determined and measured by the center of gravity and the resistance to tip-over the apparatus over any given terrain. The apparatus's weight plus the patient's weight upon the apparatus determines where the center of gravity will be for the apparatus. This new center of gravity and overall horizontal footprint will dictate if the apparatus will tip-over. The stability effectiveness of the apparatus is defined as the Apparatus's Stability Index (ASI). The higher the ASI, the less stable the apparatus becomes. As a general rule of thumb, a lower ASI not only equates to better stability of the apparatus but also indicates better performance on inclines, in non-stable surface (such as cracks, gap crossings, broken tiles, etc.).
From a stability perspective, the apparatus design offers the best solution for a versatile apparatus that is required to operate over diverse surfaces. This is because the design inherently provides a greater horizontal area (footprint) projection than standard mobile patient lift designs, resulting in a lower ASI. The design incorporates a very low ASI and uses weight reduction techniques such as hybrid composite materials. Size constraints were imposed during the design phase without compromise to safety. Design criteria have dictated that the overall apparatus is built for durability and safety. The apparatus's mobility will not be impacted by its traction ability over various surfaces (such as tile, cracks, gap crossings, broken tiles, etc.).
Other objects and advantages of the present invention will become apparent from the following detailed description of the preferred embodiment of thereof taken in conjunction with the accompanying drawings, wherein:
a, 2b, 2c and 2d are schematic presentations of the front, left side, right side and back of the main trunk unit configuration;
a, 3b, 3c and 3d are schematic presentations of the top, left side, front, and right side of the middle trunk unit configuration;
a, 4b, 4c and 4d are schematic presentations of the top, left side, front, and right side of the upper trunk unit configuration;
a, 5b and 5c are schematic presentations of the three (3) variable geometry stability fin units of the invention;
a, 6b and 6c are schematic presentations of left side wheel unit, right side wheel unit and steerable drive wheel unit of the invention;
a and 7b are schematic presentations of the left side adjustable knee support unit and the right side adjustable knee support unit of the invention;
a, 8b, 8c and 8d are schematic presentations of the left side inside view of the lifting arm unit, left side outside view of the lifting arm unit, right side inside view of the lifting arm unit, and left side outside view of the lifting arm unit of the invention;
a and 9b are schematic presentations of left side extender bar unit and the right side extender bar unit of the invention;
a and 10b are schematic presentations of the external view of the winch holder unit and winch unit of the invention;
Referring now to the drawings, wherein identical numerals indicate identical parts, and initially to
The apparatus consists of a main trunk unit 1, a middle trunk unit 2 that is nested into the main trunk unit 1 along with the upper trunk unit 3 and which is nested into the middle trunk unit 2. Variable geometry stability fin units 4A, 5A, 4B, 5B {not shown}, 4C and 5C are attached to the main trunk unit 1. The weight, overall height of the patient that is to be lifted is programmed into the apparatus's microprocessor, which in turn determine the exact size of these stability fin units 4A, 5A, 4B, 5B {not shown}, 4C and 5C. The overall height of the invention is also controlled by the microprocessor. The patient's physical size and weight dictates what the lifting arm units 8A and 8B length will be and the spread distance between these lift arm units which is determined by the length of extender bar units 14A and 14B. Elbow joint units 17A {not shown} and 17B couples lifting arm units 8A and 8B to extender bar units 14A and 14B. On the main trunk unit 1 is a set of adjustable padded knee support units, 7A and 7B which are adjusted by the caregiver to fit the patient's proportions. The positioning of the middle trunk unit 2, upper trunk unit 3, stability fin units 4A, 4B and 4C, lifting arm units 8A and 8B, and extender bar units 14A and 14B is by reversible brushless DC motors with appropriate gearheads and various linkage mechanisms [not shown] which are in the control of the caregiver by means of a handheld control unit 409 {not shown} that has a wireless data link to a transceiver unit 419 {not shown}. The transceiver unit 419 {not shown} is internally connected to the microprocessor within the device. The apparatus maneuvers by means of wheel units 6A and 6B and steerable and reversible drive wheel unit 6C. The internal power source unit [not shown] and electronics control unit [not shown] are located in compartment 12. If the patient is lying on the bed he/she can grasp handle units 16A and 16B. The patient stands on footrest platform unit 19. Once standing the patient can switch to handle units 15A and 15B if desired. Arm pad units 18A and 18B provide cushioning. Attached to the upper trunk unit 3 is the patient's back harness winch holder unit 11 and winch unit 13. Also a chest protector pad unit 10 is mounted on the middle trunk unit 2.
Referring to
a, 3b, 3c and 3d shows the external views of the middle trunk unit 2. The front and top external views of the middle trunk unit 2 shows the chest protector pad unit 10. The right side view shows opening 25 for the extender bar unit 14B along with the chest protector pad unit 10. The left side view shows opening 24 for extender bar unit 14A along with the chest protector pad unit 10.
In
a, 5b and 5c are the external views of the variable geometry stability fin units. The side view of stability A fin shows the fixed length leg 28 along with expanding horizontal leg units 35, 36 and 37 which in
In
a and 7b, shows the external front views of adjustable knee support units 7A and 7B. Knee support unit 7A consists of the horizontal adjustment plate unit 76, the vertical adjustment plate unit 77 and knee support pad 78. Horizontal adjustment plate unit 76 is attached to main trunk unit 1 by means of fasteners {not shown}, vertical adjustment plate unit 77 is attached to horizontal adjustment plate unit 76 by means of fasteners {not shown} and knee support pad 78 is permanently attached to the vertical adjustment plate unit 77 but is allowed to move in the slots by pins secured by a flange unit on each pin within adjustment plate unit 78 (not shown) and is allowed to move in the slots by pins secured by a flange unit on each pin within vertical plate unit 77 (not shown) as shown in
In
a and 9b shows the external views of extender bar units 14A and 14B. The side view of extender bar unit 14A shows extender connector rod 86 which is connected to reversible DC motor unit 91 which is connected to lifting arm 8A. Drive gear 88 is connected to a shaft {not shown} which in turn is connected to a reversible DC motor unit 90 that moves extender arm unit 8A back and forth. Gear rack 93 is connected to sleeve 89, which is the outside covering of extender bar unit 14A. It has a rectangular end and is threaded. Reversible DC motor unit 94 engages gear rack 93 that allows the extender bar unit 14A to move in and out of middle trunk unit 2. Motor units 94 and 92 are fastened to the wall of middle trunk unit 2 to hold extender bar unit 14A in place. Likewise, the side view of extender bar unit 14B shows extender connector rod 87 which is connected to reversible DC motor unit 98 which is connected to lifting arm 8B. It has a rectangular end and is threaded. Drive gear 95 is connected to a shaft {not shown} which in turn is connected to a reversible DC motor unit 97 that moves extender arm unit 8B back and forth. Gear rack 100 is connected to sleeve 96, which is the outside covering of extender bar unit 14B. Reversible DC motor unit 101 engages gear rack 100 that allows the extender bar unit 14B to move in and out of middle trunk unit 2. Motor units 99 and 101 are fastened to the wall of middle trunk unit 2 to hold extender bar unit 14B in place.
In
As shown in
In
All RF and IR transmissions are subject to noise, interference and fading. Most short-range RF and IR wireless data communications use some form of packet protocol to automatically assure information is received correctly at the correct destination. A packet generally includes a preamble, a start symbol, routing instruct, packet ID, message segment, error correct bits, and other information (if required). Various correction schemes can be employed to minimize transmission errors.
In describing the invention, reference has been made to a preferred embodiment and illustrative advantages of the invention. Those skilled in the art, however, and familiar with the instant disclosure of the subject invention, may recognize that numerous other modifications, variations, and adaptations may be made without departing from the scope of the invention. With these modifications, variations and adaptations can be applied to the various units within the apparatus.
This application claims the benefit of U.S. Provisional Application No. 60/592,905 filed Jul. 31, 2004 and U.S. Provisional Application No. 60/601,832 filed Aug. 16, 2004, incorporated by reference herein in their entirety.
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