Patent Publication Number: US-6212712-B1

Title: Mobile stretcher with lateral recumbant mechanism

Description:
BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     The subject invention is related to an improved mobile stretcher, and more specifically to an improved mobile stretcher with a lateral recumbent positioning mechanism. The subject invention is more directly related to an improved mobile stretcher that tilts patients into a laterally raised position and secures the patients to the stretcher during and after tilting. 
     2. Description of the Related Art 
     Proper care of patients may require positioning, repositioning or transporting patients. Often the patient is non-ambulatory and must be situated in a specific position to perform medical examinations, surgery or other medical procedures. If the patient is non-ambulatory for a protracted period of time, it is often necessary to reposition the patient to avoid bed sores. In other instances the patient needs to be transported from one bed to another, or from a bed to a gurney or vice-versa. Mechanisms for positioning, repositioning, and transporting patients are well known in the prior art. 
     Devices for transferring non-ambulatory patients from one bed to another are disclosed in U.S. Pat. Nos. 2,174,434, 5,022,810, 2,542,963, 3,403,411 and G.B. 2477. U.S. Pat. Nos. 2,174,434, 3,403,411, 2,542,963 and G.B. 2477 all teach devices for handling non-ambulatory patients, where the device provides a side tilting platform to aid in transferring the non-ambulatory patient onto or off of a hospital bed. U.S. Pat. No. 5,022,810 also teaches a device for transferring a non-ambulatory patient from and to a hospital bed. U.S. Pat. No. 5,022,810 discloses a laterally sliding transfer platform in addition to a side tilting platform. 
     U.S. Pat. No. 4,658,450 teaches a multi-position bed for positioning a patient for ease of transportation or to allow certain medical procedures. Multiple linkages pivotally attached to the bed and bed frame allow the bed to be situated into the various positions. The bed can be adjusted to laterally position the patient, or to provide a backrest which raises the patient&#39;s torso and head. 
     U.S. Pat. No. 4,939,801 discloses a transporting and turning gurney for receiving and lifting a patient from a hospital bed, for transporting and depositing the patient on a hospital operating table, and for lifting and turning a patient for surgery. U.S. Pat. No. 4,939,801 teaches a rectangular frame (designed to receive a patient within the frame perimeter), a pair of support sheets, and a multiplicity of straps for supporting and attaching the patient to the frame. The frame can be rotated about its longitudinal axis for rotating the patient as needed. 
     There still exists a need to position a patient in a lateral recumbent position on a mobile bed or stretcher, and secure that patient to the mobile bed or stretcher while the patient is in a lateral recumbent position. 
     SUMMARY OF THE INVENTION 
     The current invention is of an improved mobile stretcher, comprising a first lateral recumbent positioning means, a second lateral recumbent positioning means, one or more casters, a lower base frame, one or more lifting arms, an upper base frame, a mattress frame, and a patient retention means. The casters are rotatably attached to the lower base frame and the lower base frame is connected to the upper base frame via the lifting arms. The lifting arms are extendable and retractable; when the lifting arms are in the extended and locked position the mattress frame is positioned above the lower base frame. 
     The upper base frame and the mattress frame each form rectangles and are pivotally connected to the other along one of the long ends of their rectangles. Cross bars are positioned inside the mattress frame and the upper base frames connecting the first and second long ends of the upper base frame rectangle and the first and second long ends of the mattress frame rectangle. The cross bars are parallel to the short ends of the upper base frame rectangle and the short ends of the mattress frame rectangle. The first lateral recumbent positioning means has a first end and a second end, and the first lateral recumbent positioning means first end is connected to one of the cross bars of the upper base frame. The first lateral recumbent positioning means second end is connected to one of the cross bars of the mattress frame. The second lateral recumbent positioning means also has a first end and a second end. The second lateral recumbent positioning means first end is connected to another cross bar of the upper base frame rectangle, and the second lateral recumbent positioning means second end is connected to another cross bar of the mattress frame rectangle. 
     Each of the lateral recumbent positioning means has a retracted position and an extended position so that when each of the lateral recumbent positioning means is in the retracted position the angle between each of the short ends of the upper base frame rectangle and each of the short ends of the mattress frame rectangle is an angle close to 0°. Accordingly, when the lateral recumbent positioning means is in the extended position the angle between each of the short ends of the upper base frame rectangle and each of the short ends of the mattress frame rectangle is an angle greater than zero. The preferred angle between each of the short ends of the upper base frame rectangle and each of the short ends of the mattress frame rectangle (i.e. the lateral recumbent position) is an angle between 60° and 65°. 
     It is therefore an object of this invention to provide an improved mobile stretcher with a lateral recumbent positioning mechanism. 
     It is yet a further object of this invention to provide an improved mobile stretcher with a lateral recumbent positioning mechanism and a means for securing a patient to the mobile stretcher. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A better understanding of the present invention can be obtained from the detailed description of exemplary embodiments set forth below, to be considered in conjunction with the attached drawings, in which: 
     FIG. 1 depicts, in perspective view, the Improved Mobile Stretcher with a Lateral Recumbent Positioning Mechanism. 
     FIG. 2 depicts, in perspective view, the Improved Mobile Stretcher with a Lateral Recumbent Positioning Mechanism in the lateral recumbent position. 
     FIG. 3 depicts, in a side view, the Improved Mobile Stretcher with a Lateral Recumbent Positioning Mechanism. 
     FIG. 4 depicts, in a side view, the Improved Mobile Stretcher with a Lateral Recumbent Positioning Mechanism, in the lateral recumbent position. 
     FIG. 5 depicts, in a side view, the Improved Mobile Stretcher with a Lateral Recumbent Positioning Mechanism, in an intermediate recumbent position. Lateral Recumbent Positioning Mechanism in the lateral recumbent position. 
     FIG. 6 depicts, in a side view, a patient secured to the Improved Mobile Stretcher with a Lateral Recumbent Positioning Mechanism. 
     FIG. 7 depicts, in a side view, a patient secured to the Improved Mobile Stretcher with a Lateral Recumbent Positioning Mechanism, in the lateral recumbent position. 
     FIG. 8 depicts the side view of a two bar linkage embodiment of the lateral recumbent positioning mechanism. 
     FIG. 9 depicts, in perspective view, the single bar embodiment of the lateral recumbent positioning mechanism. 
     FIG. 10 illustrates the piston/cylinder embodiment of the lateral recumbent positioning mechanism. 
     FIG. 11 illustrates the D-shaped ring embodiment of the strap connection means. 
     FIG. 12 depicts an alternative embodiment of the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 depicts in a perspective view, the Improved Mobile Stretcher with a Lateral Recumbent Positioning Mechanism  1  in the horizontal position. The Improved Mobile Stretcher with a Lateral Recumbent Positioning Mechanism  1  is comprised of a lower base frame  3  supported by casters  2 . The lower base frame  3  is connected to the upper base frame  4  by a pair of lifting arms  12 . The upper base frame  4  forms a rectangle comprised of an upper base first short member  20 , an upper base second short member  22  (FIG.  2 ), an upper base first long member  21  and an upper base second long member  23  (FIG.  9 ). Resting on top of the upper base frame  4  is the mattress frame  5  such that the angle between the upper base frame  4  and the mattress frame  5  is an angle approximate to 0°. The mattress  6  is positioned atop the mattress frame  5 . The mattress frame  5  forms a rectangle having a mattress frame first long member  25 , a mattress frame second long member  27  (FIG.  9 ), a mattress frame first short member  24  and a mattress frame second short member  26  (FIG.  9 ). Connected to the mattress frame first and second long members ( 25  and  27 ) is the patient retention means consisting of a pair of strap assemblies each pair comprising a first strap  7  and a second strap  9 . The pair of first straps  7  is connected to the mattress frame first long member  25  at each first strap  7  first end. A female buckle assembly is secured to the first strap  7  second end. The pair of second straps  9  are connected to the mattress frame second long member  27  at each second strap  9  first end. A male buckle assembly is connected to the second strap  9  second end. While it is preferred that three strap assemblies with head straps be used, the strap assemblies may be comprised of one strap assembly, two strap assemblies, or more than three strap assemblies. Additionally, while the preferred mode of connecting the first strap  7  to the second strap is a male/female seat belt buckle assembly  8 , any number of other types of assemblies may be employed, such as Velcro® hook and loop fasteners, traditional self locking belt buckle assemblies, D-shaped rings, mating male and female snaps or hooks. 
     FIG. 2 illustrates in perspective view the Improved Mobile Stretcher with a Lateral Recumbent Positioning Mechanism  1  in the lateral recumbent position. In the lateral recumbent position the mattress frame  5 , and accordingly the mattress  6 , are at approximately a 60° to 65° angle to the upper base frame  4 . The mattress frame  5  is supported and held steady at the approximately 60° to 65° angle by the lateral recumbent positioning mechanism  11 . When the mattress frame  5  is in the approximately 60° to 65° angle with respect to the upper base frame  4  the lateral recumbent positioning mechanism  11  is in the extended position. Conversely, when the mattress frame  5  is in the approximately 0° angle with respect to the upper base frame  4 , the lateral recumbent positioning mechanism  11  is in the retracted position. Due to cost and ease of construction it is preferred to construct the lateral recumbent positioning mechanism  11  from metals such as aluminum, carbon steel or stainless steel. However, plastics or composites may be used that are of sufficient strength to support the required loads. The standard in the industry is that a stretcher be able to support at least 500 pounds. It is preferred that the lateral recumbent positioning mechanism  11  be a multi-piece mechanism with multiple degrees of freedom in order to retract when the Improved Mobile Stretcher with a Lateral Recumbent Positioning Mechanism  1  is in the horizontal position and to be able to extend and lock when the Improved Mobile Stretcher with a Lateral Recumbent Positioning Mechanism  1  is in the lateral recumbent position. However, the lateral recumbent positioning mechanism  11  may be any device capable of extending and supporting the mattress frame  5  in its 60° to 65° angle and retracting when the mattress frame  5  is in the horizontal position (0° angle). Accordingly, the lateral recumbent positioning mechanism  11  may also be a cylinder and piston device that is gas, hydraulically, electrically or mechanically actuated. 
     FIG. 3 illustrates in side view the Improved Mobile Stretcher with a Lateral Recumbent Positioning Mechanism  1  in the horizontal position. The hinge mechanism  13  pivotally connects the upper base frame second long member  23  (FIG. 9) to the mattress frame second long member  27  (FIG.  9 ). 
     FIG. 4 illustrates in side view the Improved Mobile Stretcher with a Lateral Recumbent Positioning Mechanism  1  in the lateral recumbent position. The hinge mechanism  13  rotatably connects the upper base frame second long member  23  (FIG. 9) to the mattress frame second long member  27  (FIG. 9) and provides a point which the mattress frame  5  is allowed to pivot about the upper base frame  4 . 
     It is well understood in the medical profession that placement of a patient into a lateral recumbent position is beneficial in that an unconscious or incapacitated patient is susceptible to strangulation upon or drowning in the patient&#39;s own regurgitated materials. The lateral recumbent position is understood to be that position wherein the patient is lying on his side. It has been determined and is commonly accepted medical knowledge that a lateral recumbent position wherein the plane of the patient&#39;s back makes an angle of approximately 60° to 65° with respect to the horizon is optimal, in that gravity will work to clear the patient&#39;s air passage while the patient is in this position. 
     In operation, the attending medical personnel position the patient onto the mattress  6  and secure the patient thereto by connecting the series of first straps  7  to the series of second straps  9 . The preferred connection mechanism to connect the series of first straps  7  to the series of second straps  9  is a male/female buckle assembly  8 . Typical male/female buckle assemblies  8  are utilized on current mobile stretchers. The male/female buckle assemblies  8  are preferred since they are quick and easy to connect and disconnect. If it is necessary, or anticipated, that the patient be positioned into the lateral recumbent position, the attending medical personnel can raise the mattress frame first long member  25  away from the upper base frame first long member  21  to the desired position, typically until approximately a 60° to 65° angle exists between the upper base frame short members ( 20  and  22 ) and the mattress frame short members ( 24  and  26 ). The lateral recumbent positioning mechanism  11  is then secured into a locked position to maintain the approximate 60° to 65° angle between the upper base frame short members ( 20  and  22 ) and the mattress frame short members ( 24  and  26 ) for as long as necessary. Often the patients are attended to by emergency medical personnel and the care provided must be fast and efficient. It is important that the lateral recumbent positioning mechanism  11  can be positioned in the locked position easily—preferably in a single motion, and be self locking. 
     Various embodiments of the lateral recumbent positioning mechanism  11  exist. FIG. 8 depicts the two bar linkage embodiment of the lateral recumbent positioning mechanism  11 . The two bar linkage embodiment is comprised of a first member  30  and a second member  31  pivotally connected to each other on one end. The second member  31  is pivotally connected to the upper base frame cross bars ( 35  and  36 ) on its other end, and the first member  30  is pivotally connected to the upper base frame  4  on its other end. The pivoting connections allow the first member  30  and the second member  31  to be positioned substantially parallel to one another when the lateral recumbent positioning mechanism  11  is in the retracted position. Conversely, when the lateral recumbent positioning mechanism  11  is in the extended position the major axis of each of the first member  30  and the second member  31  lie on the same line, and the length of the recumbent positioning mechanism  11  is approximately the sum of the lengths of the first member  30  and the second member  31 . Further, when the lateral recumbent positioning mechanism  11  is in the extended position, the first member  30  and the second member  31  lock into position and tilt the mattress frame  5  with respect to the upper base frame  4 . The first member  30  and the second member  31  will not return to the retracted position until an external force is applied to the point about which the first member  30  and the second member  31  are connected to each other. 
     FIG. 9 illustrates a single bar  15  linkage embodiment of the lateral recumbent positioning mechanism. The single bar  15  is pivotally connected along the plane defined by the mattress frame  5  and is formed having multiple notches along the length of the single bar  15 . The multiple notches are each formed for mating with the cross bar  14  so that when any of the notches is positioned around the cross bar  14  the mattress frame  5  is tilted with respect with the upper base frame  4 . Providing multiple notches on the single bar  15  allows multiple angles of tilt between the mattress frame  5  and the upper base frame  4 . The single bar  15  linkage embodiment can be unlocked by simply lifting the mattress frame  5  upwards and the single bar  15  will demate from the cross bar  14 . 
     FIG. 10 depicts a piston/cylinder  16  arrangement of the lateral recumbent positioning mechanism. The piston/cylinder  16  may contain a compressed gas, hydraulic fluid or a mechanical device. The preferred compressed gas is air, however any suitable gas may be employed, such as nitrogen. The preferred mechanical device contained inside the piston/cylinder  16  is a spring, however alternatively facing stacked washers may be employed as well. 
     In FIG. 12 an alternative embodiment of the patient retention means is illustrated. Head straps  37  and  38  are connected to a first strap  7  and a second strap  9  and an additional first strap  7  and second strap  9  are shown. Also shown is an additional connection means. 
     When the patient is in the lateral recumbent position the risk that the patient will choke on his or her own fluids, such as from regurgitation, is significantly reduced. Therefore, if the patient is otherwise stable, the attending medical staff may give reduced priority to monitoring the subject patient for choking from said fluids and the attending medical staff is able to engage in other medical care tasks. 
     The foregoing disclosure and description of the invention is illustrative and explanatory thereof, and various changes in the size, shape, and materials, as well as in the details of the illustrated and described invention may be made without departing from the spirit of the invention.