Patent Application
20200397632
The present disclosure relates generally to an emergency stretcher of the type that is used to transport patients in an ambulance or within a hospital. More particularly, the present disclosure relates to a self-propelled track drive module that can be releasably secured to an emergency stretcher for use on uneven or loosely packed surfaces.
Emergency stretchers are known for transporting patients in an ambulance and for transporting patients within a hospital. A typical emergency stretcher includes a patient litter or cot that is supported on an X-frame undercarriage equipped with wheels. The X-frame (scissor lift) allows the patient litter to be raised and lowered to facilitate loading of a patient onto the litter, loading the stretcher into an ambulance and subsequently unloading the stretcher from the ambulance, etc. Although the prior art emergency stretchers are generally adequate for their intended purposes, they are not satisfactory in all regards.
Known emergency stretchers are constructed to move on a set of caster wheels, which are suitable for use on smooth surfaces including hospital floors, concrete pathways, paved driveways, etc. As will be apparent, the caster wheels are not well suited for use on uneven or loosely packed surfaces including gravel driveways, deep snow, sand, cobblestone walkways, grass, fields, wooded areas etc. When operated on uneven or loosely packed surfaces the caster wheels of a prior art emergency stretcher may become obstructed, entangled or buried, making it difficult or even impossible for emergency medical service (EMS) providers to transport a patient in the normal fashion. Under such conditions it may be necessary to use a specialized patient transport vehicle, such as for instance an all-terrain vehicle equipped with a patient litter. Alternatively, it may be necessary for the EMS providers to lift the stretcher, including the patient and any medical equipment associated therewith, over the uneven or loosely packed surface.
Of course, a specialized transport vehicle may not be readily available and therefore valuable time may be wasted waiting for such a vehicle to arrive. On the other hand, lifting the stretcher including the patient and medical equipment, even over a short distance, unacceptably increases the risk of an injury occurring to the EMS providers and/or volunteers assisting with the patient transport.
In fact, the problem of injuries occurring to EMS providers during patient transport is a serious and long-standing one. According to a study that was published in December 2007 (Studnek et al., “On the job illness and injury resulting in lost work time among a national cohort of emergency medical services professionals,” American Journal of Industrial Medicine, Vol. 50, Issue 12, pp. 921-931) almost 10% of all emergency medical technicians and paramedics in the United States at any given time were missing work because of a job-related injury or illness, which increases to almost 19% in busy systems that handle more than 40 calls per week. The most common types of injuries, accounting for nearly 30% of all workplace injuries and illness occurring in EMS providers, are body motion injuries including back and neck sprains and strains caused by excessive physical effort, awkward posture or repetitive movement. Slips, trips and falls account for another 15% of workplace injuries and illness in EMS providers, wherein 40% of such incidents involved the EMS provider going up or down a step or curb.
The high incidence of workplace injuries in EMS providers may be attributed to performing repetitive movements while lifting or moving a heavy load. For instance, a prior art stretcher weighs approximately 120 pounds when empty, but the total weight may exceed 350 pounds when loaded with a patient and medical equipment. In the case of bariatric patient transfer the total weight that is being transported exceeds 350 pounds by a considerable amount. Other factors that contribute to the occurrence of workplace injuries include shifting of the patient's balance or position while being transported, which requires the EMS provider to compensate, or manoeuvring through narrow passages, which requires the EMS provider to bend or twist.
Another problem associated with prior art emergency stretchers is that two EMS providers are required to transport a patient safely—one EMS provider guiding the foot-end of the stretcher and the other EMS provider guiding the head-end of the stretcher. As a result, neither EMS provider is available to retrieve equipment from the ambulance or to attend to another patient, etc.
Further, the prior art emergency stretcher is typically moved with the patient litter in the raised position. Although this configuration allows the EMS providers to move the patient without being required to bend down to reach the patient litter, it also has the unfortunate effect of raising the centre of mass, which increases the likelihood that the emergency stretcher will tip over. Tipping of the emergency stretcher is undesirable because the patient being transported may be thrown to the ground, causing bodily harm to the patient, and/or the EMS providers may suffer an injury while attempting to compensate for the tipping motion.
It would therefore be beneficial to provide methods and apparatus that overcome at least some of the above-mentioned disadvantages and/or limitations that are associated with prior art emergency stretchers.
In accordance with an aspect of at least one embodiment there is provided a self-propelled track drive module for an emergency stretcher, comprising: a left-side track drive unit and a right-side track drive unit; and a frame having a front end and a rear end and being disposed between the left-side track drive unit and the right-side track drive unit, the frame comprising a mounting structure for receiving an emergency stretcher and for releasably securing the emergency stretcher to the frame, wherein the mounting structure is configured to support the emergency stretcher such that rolling wheels of the emergency stretcher do not contact a ground surface therebelow when the emergency stretcher is in a mounted condition.
In accordance with an aspect of at least one embodiment there is provided a system for transporting a patient, comprising: an emergency stretcher comprising: a bed upon which the patient is placed for transport; a scissor lift assembly supporting the bed in a height-adjustable fashion; and a first set of caster wheels carried by the front-end of the scissor lift and a second set of caster wheels carried by the rear-end of the scissor lift; and a self-propelled track drive module, comprising: a left-side track drive unit and a right-side track drive unit; and a frame having a front end and a rear end and being disposed between the left-side track drive unit and the right-side track drive unit, the frame comprising a mounting structure for receiving the emergency stretcher and for releasably securing the emergency stretcher to the frame, wherein the mounting structure is configured to support the emergency stretcher such that the first set of caster wheels and the second set of caster wheels do not contact a ground surface therebelow when the emergency stretcher is in a mounted condition.
In accordance with an aspect of at least one embodiment there is provided a method for transporting a patient, comprising: releasably securing an emergency stretcher to a self-propelled track drive module, wherein: the emergency stretcher comprises a bed upon which the patient is placed for transport, a scissor lift system for supporting the bed in a height-adjustable fashion, and a set of caster wheels for rolling on a ground surface; and the self-propelled track drive module comprises a left-side track drive unit and a right-side track drive unit and a frame having a front end and a rear end and being disposed between the left-side track drive unit and the right-side track drive unit, the frame comprising a mounting structure for receiving the emergency; and wherein the caster wheels do not contact a ground surface therebelow when the emergency stretcher is mounted to the self-propelled track drive module; transporting the patient over a first terrain in a self-propelled mode of operation in which the tracks of the self-propelled track drive module engage a ground surface of the first terrain and are powered by an on-board power plant thereof; releasing the emergency stretcher from the self-propelled track drive module and placing the set of caster wheels into contact with a ground surface of a second terrain; and transporting the patient over the ground surface of the second terrain in a manually propelled mode of operation in which the emergency stretcher rolls on the set of caster wheels.
The instant invention will now be described by way of example only, and with reference to the attached drawings, wherein similar reference numerals denote similar elements throughout the several views, and in which:
The following description is presented to enable a person skilled in the art to make and use the invention and is provided in the context of a particular application and its requirements. Various modifications to the disclosed embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the scope of the invention. Thus, the present invention is not intended to be limited to the embodiments disclosed but is to be accorded the widest scope consistent with the principles and features disclosed herein.
Throughout the description and in the appended claims the terms “left” and “right” are understood to be with respect to an operator positioned at the foot end of the emergency stretcher and facing toward the emergency stretcher. The term “front” refers to the head end of the emergency stretcher and the term “rear” refers to the foot end of the emergency stretcher.
Referring to
The track drive module 100 also includes a power plant (which is not illustrated in
The track drive module 100 that is shown in
Of course, the emergency stretcher optionally includes additional actuators and mechanisms for inclining the bed, either in whole or in part. For instance, the head end of the bed may be pivotally coupled to the foot end such that the head end may be inclined as shown in
In an exemplary embodiment, a left-side electric drive motor (not illustrated) is mounted to the undercarriage frame 400 of the left-side track drive unit 102 and a right-side electric drive motor (not illustrated) is mounted to the undercarriage frame 400 of the right-side track drive unit 104. During use, the not illustrated left-side electric drive motor powers the left-side track drive unit 102 via a not illustrated left-side power transfer unit coupled to the drive sprocket of the left-side track drive unit 102. Similarly, the not illustrated right-side electric drive motor powers the right-side track unit 104 via a not illustrated right-side power transfer unit coupled to the drive sprocket 402 of the right-side track drive unit 104. Advantageously, the left-side track drive unit 102 and the right-side track drive unit 104 are powered independently in order to improve maneuverability of the track drive module 100, such as for instance by enabling the tracks to counter rotate for maneuvering in tight areas.
Referring now to
In an alternative embodiment (not illustrated) the front-left and front-right channel supports are replaced by a single front tray with raised edges, which is sized and positioned for receiving and supporting both of the front casters wheels of the emergency stretcher 200 (i.e., the caster wheels that are carried at the head-end of the scissor lift). Similarly, in the alternative embodiment the rear-left and rear-right channel supports are replaced by a single rear tray with raised edges, which is sized and positioned for receiving and supporting both of the rear caster wheels of the emergency stretcher 200 (i.e., the caster wheels that are carried at the foot-end of the scissor lift). In both embodiments, the caster wheels of the emergency stretcher are supported out of contact with the ground surface therebelow and are protected from various obstacles on the uneven terrain as was discussed above.
The track drive module 100 and the emergency stretcher 200 cooperate to form a self-propelled patient transfer system. Since the system uses a standard emergency stretcher 200 it is not necessary to modify existing ambulances etc., which are already configured for transporting the standard emergency stretcher 200. Further, the standard emergency stretcher 200 is used to transport the patient from the ambulance to the hospital, and therefore no special accommodations need to be made in hospital emergency rooms etc. The detachable nature of the track drive module 100 provides a versatile system, which may be used for transporting patients over surfaces that are even, smooth and hard-packed as well as over surfaces that are uneven, hilly, soft-packed or obstructed by branches, rocks or steps etc.
When a patient is being transferred over even, hard surfaces etc. it is not necessary to use the track drive module 100 with the emergency stretcher 200. For instance, transporting a patient down a paved driveway or between an ambulance and a hospital entrance may be done in the known way by simply rolling the emergency stretcher on the caster wheels.
Of course, when a patient is being transferred over uneven or soft-packed surfaces the caster wheels may become entangled, sink into the ground, or otherwise unable to roll. Under such circumstances it is advantageous to use the track drive module 100 with the emergency stretcher 200. A procedure for transporting a patient over such surfaces may include the following sequence of steps, but it is to be understood that some steps may be omitted, other steps may be added, and some steps may be performed in a different order. To begin, the emergency stretcher 200 is provided, such as for example by unloading the emergency stretcher 200 from the back of an ambulance. The track drive module 100 is then provided next to the emergency stretcher 200. The track drive module 100 may be stowed within the ambulance and unloaded at the scene, or it may be delivered by a special unit upon request. The emergency stretcher 200 is then mounted onto the track drive module 100 and is secured thereto. The operator then uses a controller to drive the track drive module 100 under its own power directly to the patient requiring transport, which includes driving the track drive module 100 over the uneven or soft-packed surface. After the patient is secured in the bed of the emergency stretcher 200, and preferably with the emergency stretcher 200 in the lowered condition, the track drive module 100 is driven back toward the ambulance, which once again includes driving the track drive module 100 over the uneven or soft-packed surface. The emergency stretcher 200 is uncoupled from the track drive module 100 and the caster wheels of the emergency stretcher 200 are placed into contact with the ground. The patient is then either wheeled across the ground to the ambulance or is loaded directly into the back of the ambulance while still secured to the emergency stretcher 200. Finally, the track drive module is either stowed back in its place within the ambulance or it is returned to the special unit to be removed from the scene. Optionally, the track drive module 100 may be driven over even or uneven ground with the emergency stretcher 200 in the raised or semi-raised condition so as to improve operator comfort and to reduce the risk of operator injury. Further optionally, the emergency stretcher 200 and the track drive module 100 can remain coupled together, with the patient secured on the emergency stretcher 200, and be loaded into an ambulance that is equipped for loading and securing the coupled together emergency stretcher 200 and the track drive module 100 as a unit.
During use, the operator may cause the left track drive unit 102 and the right track drive unit 104 to rotate in the same direction forward or reverse, or to counter-rotate so as to turn or even spin on the spot. The tracks 408 are capable of driving the track drive module 100 and emergency stretcher 200 over terrain that includes rocks, sticks, ditches, inclines, stairs, curbs, sand, snow, mud, gravel, grass etc. When transporting a patient across the types of non-standard terrains that are mentioned above it is recommended for two operators (i.e., EMS providers) to accompany the emergency stretcher, and it is recommended that the emergency stretcher is in the lowered condition in order to lower the center of gravity and thereby increase the stability of the unit. On the other hand, when transporting a patient across level terrain or within a hospital or other building it may be adequate for only one operator to accompany the emergency stretcher, the emergency stretcher may be in the raised or semi-raised condition so as to improve operator comfort and to reduce the risk of operator injury. Thus, a second operator becomes available to retrieve equipment from the ambulance or assist other patients, etc.
Optionally, an operator may use a remote-control unit, in particular a wireless remote-control unit, to control the track drive unit 100 from a safe distance. For instance, the operator may remotely pilot the track drive unit 100 equipped with an emergency stretcher 200 to a patient that is injured but still capable of climbing onto the fully lowered bed of the emergency stretcher 200. Once the patient has climbed onto the bed and preferably secured a patient restraint, the operator may remotely pilot the track drive unit 100 along a return path. The remote-control self-propelled mode is useful if the patient is in a hazardous area, such as for instance an area with biological, chemical, or nuclear contamination or even under combat conditions for military applications. Although remote-control operation of the emergency stretcher is not preferred it can nevertheless be used to retrieve a patient without putting an operator at risk, and without wasting valuable time waiting for specialized protective equipment to arrive and/or donning such protective equipment before entering a hazardous area.
In the description of the invention herein, it is understood that a word appearing in the singular encompasses its plural counterpart, and a word appearing in the plural encompasses its singular counterpart, unless implicitly or explicitly understood or stated otherwise. For instance, unless the context indicates otherwise, a singular reference, such as “a” or “an” means “one or more”. Furthermore, it is understood that for any given component or embodiment described herein, any of the possible candidates or alternatives listed for that component may generally be used individually or in combination with one another, unless implicitly or explicitly understood or stated otherwise. Additionally, it will be understood that any list of such candidates or alternatives is merely illustrative, not limiting, unless implicitly or explicitly understood or stated otherwise. It is also to be understood, where appropriate, like reference numerals may refer to corresponding parts throughout the several views of the drawings for simplicity of understanding.
Throughout the description and claims of this specification, the words “comprise”, “including”, “having” and “contain” and variations of the words, for example “comprising” and “comprises” etc., mean “including but not limited to”, and are not intended to (and do not) exclude other components.
It will be appreciated that variations to the foregoing embodiments of the invention can be made while still falling within the scope of the invention. Each feature disclosed in this specification, unless stated otherwise, may be replaced by alternative features serving the same, equivalent or similar purpose. Thus, unless stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.
The use of any and all examples, or exemplary language (“for instance”, “such as”, “for example”, “e.g.” and like language) provided herein, is intended merely to better illustrate the invention and does not indicate a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.
Any steps described in this specification may be performed in any order or simultaneously unless stated or the context requires otherwise.
All of the features disclosed in this specification may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. In particular, the preferred features of the invention are applicable to all aspects of the invention and may be used in any combination. Likewise, features described in non-essential combinations may be used separately (not in combination).
This application claims the benefit of U.S. Provisional Patent Application No. 62/864,243, filed Jun. 20, 2019, and incorporates the disclosure of the application by reference.
| Number | Date | Country | |
|---|---|---|---|
| 62864243 | Jun 2019 | US |
