AU783695B2 - A height adjustable stretcher undercarriage - Google Patents

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT Name of Applicant: Actual Inventor: FERNO AUSTRALIA PTY LTD Frederick Adrian Carlyle LITTLE CULLEN CO., Patent Trade Mark Attorneys, 239 George Street, Brisbane, QId. 4000, Australia.

Address for Service: Invention Title: A HEIGHT ADJUSTABLE STRETCHER

UNDERCARRIAGE

Details of Associated Provisional Application: PQ4389 1 December 1999 The following statement is a full description of this invention, including the best method of performing it known to us: FIELD OF INVENTION This invention relates to a height adjustable and collapsible stretcher undercarriage for transporting patients. In particular, the invention is concerned with a stretcher undercarriage that collapses when loaded into a loading bay of an ambulance and automatically adjusts to the height of the bay after having been withdrawn from the bay.

BACKGROUND OF THE INVENTION Although the invention has been designed primarily for use as a stretcher undercarriage and will therefore be described in this context, it should be appreciated that the invention may have other uses. For instance, the invention may be used as a height adjustable and collapsible cart for the transportation of goods.

Stretcher undercarriages (from hereon referred to simply as an undercarriage) typically have an essentially rectangular patient support frame with collapsible wheeled leg assemblies. The leg assemblies enable the stretcher to be loaded onto the back of an ambulance (ie. ambulance loading bay) by collapsing towards an underside of the support frame. In use, the leg assembly at a leading end of the undercarriage (ie. the end of the undercarriage that first enters the loading bay) eo collapses against the undercarriage when loading into the bay, followed by the collapsing of the trailing leg assembly as the undercarriage is pushed further into the .i 20 bay. The leg assemblies may be collapsed individually using levers attached to the o°o ~trailing end of the undercarriage. The reverse of this process occurs when the undercarriage is being unloaded from the bay, with the leg assemblies extending to ground level under their own weight or by spring action when they are no longer supported by the loading bay.

25 Height adjustable undercarriages are known in the art. One such undercarriage is described in the specification of international application number PCT/AU96/00702. A disadvantage with some known undercarriages is that once having been unloaded from a bay, the undercarriage may revert to a default height that may be different to that of the bay. Having to reset the height of a patient-bearing undercarriage for loading into the same bay (or a bay of similar elevation) may cause discomfort to the patient whom may experience a "jolt" when adjusting the height or when loading into a bay of lower elevation. Another disadvantage is that having to adjust the height of the undercarriage will place strain on the operator of the undercarriage.

SUMMARY OF THE INVENTION It is an object of the invention to provide a stretcher undercarriage which at least minimises the disadvantages referred to above.

According to the present invention, there is provided a height adjustable and collapsible stretcher undercarriage for loading into a loading bay of an ambulance, said undercarriage having: a patient support frame with a leading end and a trailing end; a leading wheeled leg assembly having legs ending in groundcontacting wheels, wherein each leg of the assembly has an upper region hinged to a lower region and the upper region of each leg is pivotally mounted to a first transversely extending crosspiece of the support frame; an adjuster for releasably retaining the leg assembly at a predetermined position, the adjuster being movable between an engaged position and a released position; and a lever coupled to the leg assembly for initiating the collapsing of the leg assembly and coupled to the adjuster for moving the adjuster to the released position, and when the undercarriage is being unloaded from the bay, the upper regions of the legs pivot in unison downwardly until the wheels contact the ground i and the adjuster returns to the engaged position to maintain the support frame 20 substantially at the height of the bay.

:°'""Preferably, the adjuster comprises a retainer and a catch, the retainer is connected to the upper regions of the legs for pivotal movement therewith, the catch is pivotally mounted to the support frame adjacent the retainer, and the lever is coupled to the catch such that the catch may be pivoted from the engaged position 25 with the retainer. Alternately, the adjuster may be configured as an inertia belt system.

Preferably, the retainer is pivotally mounted to the first crosspiece and has a quadrant with teeth directed towards the trailing end of the undercarriage, and the quadrant is connected to the upper region of each leg with at least one support arm. Preferably, the catch is pivotally mounted to a second transversely extending crosspiece of the support frame and the catch has a pivoting end that is U-shaped that may engage the teeth of the quadrant. A resilient member may bias the catch into the engaged position. Preferably, the resilient member is a coil spring.

The undercarriage may be fitted with a stretcher having a seat back, and an adjustable prop may be used to hold the seat back in an upright position. The prop may have an end pivotally mounted to the first crosspiece.

The undercarriage may have one or more resilient members for assisting in the extension of the leading leg assembly when unloading the undercarriage from the bay. Preferably, at least one resilient member connects the leg assembly to the support frame for partly counteracting the weight of the leg assembly. The resilient member is preferably a spring and has ends connected to the support arm and to the second crosspiece, and is situated such that it does not collide with the first crosspiece during extension or collapsing of the leg assembly.

The spring may be any type of suitable spring, such as a torsion spring or a coil spring.

The lever may be attached to the support frame at the trailing end of the undercarriage for easy access by an operator. The lever may be spring-loaded so that it can return to a resting state. The lever may be coupled to the catch or to the leading leg assembly by a number of intermediate members operatively linked to one another.

The leading end of the undercarriage may be manually adjusted to the height of an ambulance loading bay. The undercarriage may have a handle coupled 20 to the adjustor for moving the adjustor to the released position. Preferably, the handle is attached to the support frame at the leading end of the undercarriage and is spring-loaded so that it may return to a resting state. The handle may be coupled to the catch by a number of intermediate members operatively linked to one another.

Preferably, the lever and handle have at least one common 25 intermediate member coupling the lever and handle to the catch.

The leading leg assembly may have additional members for supporting, bracing or collapsing the legs. Each leg of the leg assembly preferably has a hinged .t brace member connecting the lower region of the leg to the support frame, and the brace members are coupled to the lever such that when the lever is operated, the braces collapse towards an underside of the undercarriage.

The leading leg assembly may also have a spring-loaded strut coupling the upper regions of the legs to the hinged braces, wherein the strut assists in extending the legs from the collapsed state.

The undercarriage may have a collapsible trailing leg assembly that is located adjacent the trailing end of the patent support frame. The trailing leg assembly is preferably collapsed separately to the leading leg assembly. Trailing leg assemblies are well known in the art.

The support frame may be substantially rectangular in shape. The undercarriage may be constructed primarily from high strength but lightweight materials, and the support frame is preferably of tubular construction. The undercarriage may be fitted with a bed or mattress, with other padding or with any other device, provided that these do not interfere with the functioning of the undercarriage. Parts of the support frame may be telescopic.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a side perspective view of a stretcher undercarriage and stretcher according to an embodiment of the invention; Figure 2 is a side perspective view of part of the stretcher undercarriage and stretcher of Figure 1 but shown with a leading wheeled leg assembly partly collapsed against an elevated platform, which simulates an ambulance loading bay; Figure 3 is a perspective view showing part of the leading leg assembly and support frame of the undercarriage of Figure 1; Figure 4 is a longitudinal sectional view of part of the leading leg 20 assembly and support frame of Figure 1, with details of one of the legs of the leg assembly having been omitted; and Figure 5 is the same as Figure 4, but further details of the leg assembly have been omitted.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 25 Referring first to Figure 1, there is shown a height adjustable and collapsible stretcher undercarriage 1 and stretcher 5. The undercarriage 1 has a substantially rectangular patient support frame 2 with a leading end 3 and a trailing end 4. The support frame 2 is overlayed with a stretcher 5 having a height adjustable seat back 6. The seat back 6 is kept in an upright position with a prop 7 that extends from a transversely extending crosspiece 8 of the support frame 2.

The undercarriage 1 has two wheeled leg assemblies 9, 10. The leading leg assembly 9 has two legs 11, each pivotally mounted to crosspiece 8 and ending in a ground-contacting wheel 70. As shown in Figure 3, each leg 11 has a short upper region 12 connected by a hinge 13 to a lower region 14. A brace 6 connects the lower region 14 of each leg 11 to a part of the support frame 2 adjacent the trailing leg assembly 10, as shown in Figures 1 and 2. The braces 15 are hinged at a location identified by numeral 16 and are pivotally mounted to the support frame 2, as seen in Figure 4. A number of crosspieces 17, 18, 19 connect the two legs 11 and braces 15, as shown in Figures 1,2 and 3.

In Figure 1, the leg assemblies 9, 10 are shown in an extended state.

In Figure 2, the leading leg assembly 9 is shown in a partly collapsed state, whereby the leg assembly 9 has been partly collapsed against an elevated platform 72 (simulating an ambulance loading bay).

The undercarriage 1 has an adjuster for releasably retaining the leading leg assembly 9 at a predetermined position, the adjuster being movable between an engaged position and a released position. A hand-operated lever 20 is located at the trailing end 4 of the undercarriage 1 is and coupled to the leading leg assembly 9 for initiating the collapsing of the leg assembly 9. The lever 20 is also coupled to the adjuster for moving the adjuster to the released position. A separate lever (not shown), located at the trailing end 4, is used to collapse the trailing leg assembly As seen in Figures 3, 4 and 5, the adjuster comprises a retainer 21, 22 and a catch 23. The retainer 21, 22 has a U-shaped portion 21 and a quadrant with teeth 22 directed towards the trailing end 4 of the undercarriage 1. The U-shaped 20 portion 21 is mounted to crosspiece 8. Prop 7, which supports the seat back 6, o ooo extends from crosspiece 8 from between the mounting arms of the U-shaped portion 21. The quadrant 22 is connected to the upper region 12 of each leg 11 with a crosspiece 24. In this way, the retainer 21, 22 pivots with the upper regions 12 of the legs 11. Crosspiece 25 connects the upper region 12 of each leg 11 for additional stability.

ooo The catch 23 is pivotally mounted at a location identified by numeral 26 to a transversely extending crosspiece 80 of the support frame 2, and the catch 23 has a pivoting end that is U-shaped that may engage the toothed quadrant 22, as seen in Figure 3. An arm 28 is connected to the catch 23. A coil spring 27 under tension is connected to crosspiece 80 and to arm 28, and biases the catch 23 into the engaged position with the teeth 22. That is, the spring 27 biases the catch 23 towards the leading end 3 of the undercarriage 1.

Figures 1, 4 and 5 show that the hand lever 20 is operatively coupled to a brace 15 of the leading leg assembly 9 with elongate members 29, 30 and locking member 31. Members 29 and 30 are slideably connected to the support frame 2.

Member 31 has an elongated slot 87 through which crosspiece 17 extends, and the member 31 is slideable relative to crosspiece 17. The brace 15 has an arcuate projection 89 behind which member 31 locks when the leg assembly 9 is extended.

When the lever 20 is actuated, members 29 and 30 are caused to move, member 31 moves relative to the arcuate projection 89 to an unlocked position such that the braces 15 can bend at hinge 16, as shown in Figure 2. In this way, the legs 11 can begin to collapse, and the leg assembly 9 fully collapses when loaded into a loading bay. When the lever 20 is released, a spring (not shown) returns the lever 20 to the resting position. Coil spring 86, which is shown in Figures 4 and 5, helps to direct the sliding motion of member 30 when the lever 20 is actuated and to return member 31 to the locked position behind arcuate projection 89.

Figures 3, 4 and 5 show that the hand lever 20 is also operatively coupled to the catch 23 with elongate members 29 and 32, collar member 33 and arm 28. Member 32 has a rod portion 41 having an enlarged end 42. The rod portion 41 extends through collar member 33, as shown in Figure 3. Collar member 33 is connected to arm 28. Arm 28 has an end connected to the catch 23 and another end pivotally mounted to an underside of crosspiece 80. Arm 28 is branched, and the branched arm 34 extends upwardly and towards the leading end .i 20 3. The end of arm 34 has a collar 43. A pin 35 projects from crosspiece 80 and extends through the collar 43. The pin 35 has a coil spring 44 that separates the collar 43 from the crosspiece 80, and the pin 35 has an enlarged head so that the collar 43 cannot disengage the pin 35. When the lever 20 is actuated, members 29 and 32 are moved towards the trailing end 4, and the rod portion 41 slides within 25 collar member 33 until the enlarged end 42 also forces collar member 33 towards the trailing end 4. The movement of collar member 33 causes arm 28 to pivot towards the trailing end 4, with the result that the catch 23 disengages the toothed quadrant 22.

A handle 40 is located at the leading end 3 of the support frame 2 for manually adjusting the height of the leading end 3 of the undercarriage 1, as seen in Figures 1, 2, 4 and 5. The handle 40 is spring-loaded so that it can return to a resting state. The handle 40 is L-shaped, having an elongate portion 91 that is slideably connected to the support frame 2. As seen in Figure 3, elongate portion 91 is connected to an end of a triangular member 92, which may also be moved relative to the support frame 2. Member 92 has an end 95 that has an aperture through which extends pin 35. End 95 and collar 43 are separated by the coil spring 44 of the pin In order to manually adjust the height of the leading end 3 of the undercarriage 1 to the height of the ambulance loading bay, the operator holds the support frame 2 at the leading end 3 and squeezes the handle 40. This results in portion 91 and member 92 sliding towards the leading end 3. As end 95 compresses the spring 44, collar 43 is caused to move, causing arm 28 to pivot towards the trailing end 4. In this way, the catch 23 is pivoted out of engagement with the teeth of the quadrant 22.

With the catch 23 disengaged, the leading end 3 of the support frame 2 can be raised or lowered relative to the retainer 21, 22. When the handle 40 has been released, the catch 23 re-engages the retainer 21, 22 at an alternate location Figure 4 shows that crosspiece 80 has a projection 52 that extends towards the leading end 3. Crosspiece 24 also has a projection 53 extending towards the leading end 3. An arcuate member 55 is pivotally connected to an end of projection 53. Two coil springs 50, 51 are connected to an end of projection 52 and to an end of the arcuate member 55. When unloading the undercarriage 1 from a bay, the springs 50, 51 partly counteract the weight of the leading leg assembly 9 and 20 assist the leading leg assembly 9 to lock into the extended position. When the leg assembly 9 pivots, the arcuate member 55 pivots partly about crosspiece 8. With this arrangement, the springs 50, 51 will not collide with crosspiece 8. Springs 50, 51 are more likely to be used with undercarriages having weightier leading leg assemblies.

The leading leg assembly 9 has a spring-loaded strut 60 for helping the .i 25 leg assembly 9 expand from a collapsed state. Strut 60 has an end 63 that is slideably received within a collar 62 of crosspiece 17 (see Figure The other end 61 of the strut 60 is pivotally connected to crosspiece 24 by a bracket 88. When the leg assembly 9 is in the process of collapsing, the braces 15 fold at hinges 16, crosspiece 17 moves closer towards the support frame 2, strut end 63 slides through collar 62, and the spring 65 of the strut 60 compresses (see Figure 2).

The undercarriage 1 is able to remain at the height of the bay from which it is unloaded, so that it can again be loaded into the same bay, or into a bay of similar elevation, without having to be manually height adjusted at the leading end 3.

9 In use, the legs 11 of the leading leg assembly 9 abut the bay and the lever 20 is actuated to initiate collapsing of the leading leg assembly 9 (see Figure 2).

After having pushed the partly collapsed undercarriage 1 into the bay, another lever (not shown) is used to collapse the trailing leg assembly 10. The undercarriage 1 is also fitted with wheels 93, 94 at both ends 3, 4 of the undercarriage, which assist in the loading and unloading of the undercarriage 1 from the loading bay.

As the undercarriage 1 is being unloaded from the bay, the trailing leg assembly 10 extends to ground height under its own weight (or by spring means), following which the upper regions 12 of the leading leg assembly 9, that are no longer supported by the bay, pivot downwards under the weight of the assembly 9 and with the help of the spring-loaded strut 60 until the wheels 70 of the assembly 9 contact the ground, whereupon the catch 23 re-engages the teeth of the quadrant 22, so that the support frame 2 is held at the height of the bay.

Claims (15)

1. A height adjustable and collapsible stretcher undercarriage for loading into a loading bay of an ambulance, said undercarriage having: a patient support frame with a leading end and a trailing end; a leading wheeled leg assembly having legs ending in ground-contacting wheels, wherein each leg of the leading leg assembly has an upper region hinged to a lower region and the upper region of each leg is pivotally mounted to a first transversely extending crosspiece of the support frame; an adjuster for releasably retaining the leading leg assembly at a predetermined position, the adjuster being movable between an engaged position and a released position; a lever coupled to the leading leg assembly and to the adjuster for both initiating the collapsing of the leading leg assembly and for moving the adjuster to the released position, and when the undercarriage is being unloaded from the bay, the upper regions of the legs pivot in unison downwardly until the wheels contact the ground and the adjuster returns to the engaged position to maintain the support frame substantially at the height of the bay; and a trailing wheeled leg assembly that is collapsible independently of the leading leg assembly.

2. The undercarriage of claim 1, wherein the adjuster comprises a retainer and a catch, the retainer is connected to the upper regions of the legs for pivotal movement therewith, the catch is pivotally mounted to the support frame adjacent the retainer, Sand the lever is coupled to the catch such that the catch may be pivoted from the engaged position with the retainer.

3. The undercarriage of claim 2, wherein the retainer is pivotally mounted to the first crosspiece and has a quadrant with teeth directed towards the trailing end of the undercarriage, and the quadrant is connected to the upper region of each leg with at least one support arm, wherein the catch is pivotally mounted to a second transversely extending crosspiece of the support frame and the catch has a pivoting end that is U- shaped that may engage the teeth of the quadrant.

4. The undercarriage of claim 2 or claim 3, wherein a resilient member biases the catch into the engaged position. 11 The undercarriage of claim 4, wherein the resilient member is a coil spring.

6. The undercarriage of claim 3, wherein at least one resilient member connects the leading leg assembly to the support frame for partly counteracting the weight of the leading leg assembly.

7. The undercarriage of claim 6, wherein the resilient member is a spring and has ends connected to the support arm and to the second crosspiece and is situated such that it does not collide with the first crosspiece during extension or collapsing of the leading leg assembly.

8. The undercarriage of claim 2, wherein the lever is attached to the support frame at the trailing end of the undercarriage and is spring-loaded.

9. The undercarriage of claim 8, wherein the lever is coupled to the catch and to the leading leg assembly by a plurality of intermediate members operatively linked to one another. 0 10. The undercarriage of claim 9, further having a handle coupled to the adjuster for moving the adjuster to the released position.

11. The undercarriage of claim 10, wherein the handle is attached to the support frame at the leading end of the undercarriage and is spring-loaded.

12. The undercarriage of claim 11, wherein the handle is coupled to the catch by a plurality of intermediate members operatively linked to one another.

13. The undercarriage of claim 12, wherein the lever and handle have at least one common intermediate member that couples the lever and handle to the catch.

14. The undercarriage of any one of the preceding claims, wherein each said leg of the leading leg assembly has a hinged brace member pivotally connecting the lower region of the leg to the support frame, and the brace members are coupled to the lever such that when the lever is operated, the braces may collapse towards an underside of the undercarriage. The undercarriage of claim 14, wherein the leading leg assembly has a spring- loaded strut coupling the upper regions of the legs to the hinged braces, wherein the strut assists in extending the legs from the collapsed state.

16. The undercarriage of any one of the preceding claims when fitted with a stretcher.

17. The undercarriage of claim 16, wherein the stretcher has a seat back and an adjustable prop for holding the seat back in an upright position.

18. A height adjustable and collapsible stretcher undercarriage substantially as hereinbefore described with reference to any one of the accompanying drawings. DATED this 2 6 th day of September 2005 FERNO AUSTRALIA PTY LTD By its Patent Attorneys CULLEN CO.