Ambulance litter comprising a trolley and a carrier

Abstract

 The invention relates to an ambulance litter (1) comprising a trolley (2) and a carrier for a patient, such as a stretcher or a frame (3, 8) for e.g. an incubator (4), mounted on the trolley (2). The carrier (3, 8) is connected to the trolley (2) via at least one shock absorber (21, 22) that allows a stroke of the carrier relative to the trolley.

Description

[0001] The invention relates to an ambulance litter comprising a trolley and a carrier for a patient, such as a stretcher or a frame for e.g. an incubator, mounted on the trolley.

[0002] Such a litter is known in the art.

[0003] As explained in the prospectus of NeoSave III™, one of the great challenges in neonatology is the transportation of premature and new-born babies. It is important that the little patient be provided with an optimum of warmth and intensive care - and that the transportation be carried out safely, gently and quickly.

[0004] US 2007/0089236 discloses a neonatal transport cart. It is explained that "Transportation is typically accomplished via ground, such as by ambulance, and air, such as by airplane or helicopter. The transportation of neonatal patients by conventional means, such as in neonatal transport systems attached to medical stretchers in ambulances, exposes the patients to physical shock and vibration communicated through the relatively rigid structures, and this shock is often detrimental to the medical condition of the patient. Current neonatal transport systems do not include an effective subsystem for shock suppression."

[0005] US 2007/0089236 addresses a need "for a system to reduce the transmission of kinetic energy to neonatal patients." An air spring based system is disclosed in which air springs are mounted between a pair of stiff plates. One plate is for mounting to the isolette, and the other plate is for mounting to the support platform, such as a stretcher.

[0006] When an ambulance crashes, the patient secured to the ambulance litter, such as a baby in an incubator, is exposed to extreme forces that may cause severe or even fatal injury.

[0007] It is an object of the present invention to provide an ambulance litter which is safer at least during transport in an ambulance.

[0008] To this end, the carrier for a patient, such as a stretcher or a frame for e.g. an incubator, is connected to the trolley via at least one shock absorber that allows a stroke of the carrier relative to the trolley.

[0009] In an embodiment, the at least one shock absorber extends in longitudinal direction, i.e. the direction that corresponds to the main rolling direction of the trolley and the driving direction of the ambulance, and/or the at least one shock absorber extends substantially horizontally.

[0010] In another further embodiment, the litter comprises a plurality of shock absorbers extending parallel to and/or in line with each other.

[0011] The shock absorber or absorbers dissipate part of the energy of a crash, in particular a head-on collision, thus reducing the risk of injuring a patient secured to the carrier during such a crash.

[0012] In a more detailed embodiment, at least one shock absorber is present in the leading half and at least one shock absorber is present in the trailing half, seen in longitudinal direction, of the litter. Thus, any shock is absorbed on more than one location and tilting forces are reduced.

[0013] Although it is possible to employ e.g. one or more hydraulic and re-usable shock absorbers, it is preferred that the at least one shock absorber comprises a plastically deformable element, which effectively functions as a crumple element or zone.

[0014] In an embodiment, the deformable element comprises a cylindrical tube and a guide rod mounted inside the tube. Such absorbers are effective yet relatively compact, lightweight and inexpensive.

[0015] In a further embodiment, the tube comprises a plurality of openings arranged in a repeating pattern. The openings provide additional length of stroke, determine the amount of energy that can be dissipated and/or enhance predictability of the dissipation.

[0016] In another embodiment, the deformable element or elements are made of metal, preferably a corrosion resistant metal such as stainless steel.

[0017] In another embodiment, the shock absorber or combined shock absorbers is respectively are configured to dissipate at least 500 Joules, preferably at least 1000 Joules, preferably at least 2000 Joules of impact energy over its stroke.

[0018] In another embodiment, the carrier comprises at least two frame elements, a first frame element connected to of forming a part of the carrier and a second frame element connected, preferably releasably by means of standardized quick connectors, to the trolley. The shock absorber or absorbers are positioned between the two frame elements, e.g. between lateral struts of these elements, and the elements are slidable relative to each other when the absorber or absorbers give way.

[0019] In another embodiment, the shock absorber or shock absorbers allow a stroke of the carrier relative to the trolley of at least 1 centimeter, preferably at least 3 centimeters, preferably at least 5 centimeters, preferably at least 10 centimeters.

[0020] In a further embodiment, which is also advantageous if no shock absorbers are present in the litter, the carrier comprises a shell made of a synthetic material, preferably a composite material, such as carbon fiber reinforced polymer. Such a shell provides good strength and stiffness at a relatively low weight, adding relatively little weight to the litter and increasing ergonomics for nurses and medical staff, e.g. during transport from intensive care to an ambulance. Further, the shell can be provided with rounded edges and is relatively easy to clean.

[0021] In another embodiment, the shell comprises two elevated portions, e.g. working surfaces or surfaces for carrying equipment, such as instruments for monitoring and controlling temperature in the incubator, instruments for measuring vital physical parameters, and means for storage, and a lower surface for accommodating an incubator.

[0022] In a more detailed embodiment, the shell comprises a ridge connecting the elevated portions and extending along an edge of the lower portion, preferably behind the incubator and having a height corresponding to that of the elevated portions. Thus, the frame provides good strength and stiffness and sufficient room for accommodating an incubator.

[0023] For the sake of completeness, attention is drawn to the following prior art.

[0024] US 5,135,350 discloses a litter carrier (indicated by numeral 1 in the Figures of that publication) including a frame (3) and platform (5), secured to the frame by posts (7). The posts engage pivot bars (9), and are freely pivotable around these bars. Shock absorbers (11) are connected to support bars (13) and (15). The shock absorbers cushion the movement of the platform as it is lowered.

[0025] US 2005/0113668 discloses an MR compatible trolley (44) which can include shock absorbers atop the unit where an incubator is placed, and shock absorbing struts couple each post to a corresponding rubber wheel. Locks are provided on the wheels to restrict trolley motion, for example, during transport (e.g., in an elevator or a vehicle).

[0026] EP 0 005 424 discloses a patient litter apparatus adapted for use in an air-ambulance and comprising a force attenuating subsystem (shown in Fig. 4) which operates by transferring kinetic energy imparted to a litter rack (14) by a crash condition to a continuous cable (32), which gradually and discretely dissipates this kinetic energy as it is pulled through offset rollers (82-84) which thereby subjects the cable to continuous bending strain reversal.

[0027] DE 101 48 971 discloses a stretcher for injured miners.

[0028] The invention will now be explained in more detail with reference to the drawings, which show a preferred embodiment of the present invention.

Figure 1 is an isometric view of an ambulance litter comprising a trolley and a frame carrying an incubator in accordance with the present invention.

Figures 2A to 2C are bottom, side, and front views of frame elements of the ambulance litter shown in Figure 1.

Figures 3A to 3C are side views and a front view of a shock absorber positioned between the frame elements shown in Figures 2a to 2C.

[0029] Figure 1 shows an ambulance litter 1 comprising a trolley 2, known in itself and commercial available e.g. from Stryker®, and a carrier, in this example a shell 3 and frame (discussed below) onto which an incubator 4 for newborns has been secured. The shell 3 is made of a synthetic material, such as carbon fiber reinforced polymer. It comprises two elevated portions 3A, 3B, carrying equipment, such as instruments 5 for monitoring and controlling temperature in the incubator, vital sign indicators 6, and storage 7 for medical implements, and accommodating cylinders containing e.g. compressed air and oxygen, and a lower surface 3C accommodating the incubator 4. A ridge for strengthening and the stiffening the frame connects the elevated portions and extends along and behind the incubator (and thus hidden from view).

[0030] The shell 3 is attached to a frame 8, shown in detail in Figures 2A to 2C, comprising at least two frame elements 9, 10. A first frame element 9 is connected to the shell, e.g. by means of bolts or rivets, and comprises two parallel beams, e.g. extruded U-profiles 11 with the open sides facing each other and interconnected by lateral struts 12 welded or bolted to the beams 11. The struts 12 are provided, at their bottom sides, with glide shoes 13 to be placed on corresponding parallel beams on the trolley 2.

[0031] A plurality of, in this example three, second frame elements 10 are slidably positioned in the U-profiles 11. A leading element 10A comprises a rod 14 that fits in (standardized) hooks on the trolley 2 and that comprises on each end a glide shoe 15 that fits in the U-profiles 11. Two trailing elements 10B, 10C each comprise a strut 16 also provided with glides shoes fitted in the U-profiles and provided with (standardized) quick connectors 17 to releasably secure the frame 8, shell 3, and incubator 4 to the trolley 2.

[0032] Further, bars 18 (Figure 1) are connected to the frame 8, enabling nurses and other medical staff to move and lift the carrier 3,4 and the trolley 2 and to protect the shell 3 from contact with walls and hospital equipment.

[0033] The first frame element 9 is connected to the second frame elements 10 by means of shock absorbers 20. In this example, the shock absorbers 20 each comprise a plastically deformable tube 21 made of stainless steel and a guide rod 22 mounted inside the tube 21. The guide rods 22 are bolted to the struts 12 of the first frame element 9, whereas the leading (lateral) rod 14 and the struts 16 in the second frames 10 are provided with through holes extending in longitudinal direction (indicated by an arrow in Figures 1 and 2A) and enabling the guide rods to slide through during a crash.

[0034] The tube comprise a plurality of openings 23 arranged in a repeating pattern.

[0035] During use, the metal tubes prevent the frame elements and thus the carrier and trolley from sliding relative to each other. Locks are provided on the trolley to restrict or block motion of the trolley, for example, during transport in an ambulance. When exposed to extreme forces, e.g. during a head-on collision of the ambulance transporting the litter, the tubes collapse simultaneously, in predetermined way and over a stroke of about 20 centimeters. The guide rods prevent the tubes from buckling and enable a more predictable absorption of energy by the tubes. I.e., the metal tubes provide a crumble zone that absorbs part of the energy of the collision and enables the incubator to slide relative to the trolley reducing deceleration forces on the incubator and a neonatal patient secured in the incubator by e.g. 10 G's.

[0036] The invention is not restricted to the above-described embodiments, which can be varied in a number of ways within the scope of the claims. E.g., instead of a frame and incubator, a stretcher for adults comprising shock absorbers of appropriate dissipation can be mounted on the trolley.

Claims

1. Ambulance litter (1) comprising a trolley (2) and a carrier for a patient, such as a stretcher or a frame (3, 8) for e.g. an incubator (4), mounted on the trolley (2), characterized in that the carrier (3, 8) is connected to the trolley (2) via at least one shock absorber (21, 22) that allows a stroke of the carrier relative to the trolley.

2. Litter (1) according to claim 1, wherein the at least one shock absorber (21, 22) extends in longitudinal direction and/or substantially horizontally.

3. Litter (1) according to claim 1 or 2, comprising a plurality of shock absorbers (21, 22) extending parallel to and/or in line with each other.

4. Litter (1) according to claim 3, wherein at least one shock absorber (21, 22) is present in the leading half (~10A) and at least one shock absorber is present in the trailing half (~10C) of the litter (1).

5. Litter (1) according to any one of the preceding claims, wherein the at least one shock absorber (21, 22) comprises a plastically deformable element (21).

6. Litter (1) according to claim 5, wherein the deformable element comprises a cylindrical tube (21) and a guide rod (22) mounted inside the tube (21).

7. Litter (1) according to claim 6, wherein the tube (21) comprises a plurality of openings (23) arranged in a repeating pattern.

8. Litter (1) according to any one of claims 5-7, wherein the deformable element (21) is made of metal, preferably stainless steel.

9. Litter (1) according to any one of the preceding claims, wherein the at least one shock absorber is configures to dissipate at least 500 Joules of impact energy over its stroke.

10. Litter (1) according to any one of the preceding claims, wherein the carrier (3, 8) comprises at least two frame elements (9, 10), a first frame element (9) connected to of forming a part of the carrier (3) and a second frame element (10) connected to the trolley (2), wherein the at least one shock absorber is positioned between the two frame elements (9, 10) and wherein the elements (9, 10) are slidable relative to each other when the at least one shock absorber (21, 22) gives way.

11. Litter (1) according to any one of the preceding claims, wherein the carrier (3, 8) comprises a shell (3) made of a synthetic material, preferably a composite material, such as carbon fiber reinforced polymer.

12. Litter (1) according to claim 11, wherein the shell (3) comprises two elevated portions and a lower surface (3C) for accommodating an incubator (4).

13. Litter (1) according to claim 12, wherein the shell (3) comprises a ridge connecting the elevated portions (3A, 3B) and extending along an edge of the lower portion (3C), preferably behind the incubator (4).

14. Litter (1) according to any one of the preceding claims, wherein the at least one shock absorber (21, 22) allows a stroke of the carrier relative to the trolley of at least 1 centimeter, preferably at least 3 centimeters, preferably at least 5 centimeters, preferably at least 10 centimeters..

15. Litter (1) according to any one of the preceding claims, wherein an incubator (4) is mounted to the carrier (3, 8).

Drawing