GB2077579A - Net bed - Google Patents

Abstract

A net bed comprises a flexible web (1) of mesh or net form slung between two generally parallel shaft assemblies (2 and 3) supported in support crutches (5-8) of a support frame (4). The shaft assemblies (2 and 3) each comprise a tubular shaft (9) around which the corresponding end of the net (1) is wound and which extends between end fittings (10 and 11) which fit into the support crutches. Each shaft (9) can be turned by an end winding handle (12) and has net retaining hooks (19) which are inclined to the radial and "handed", the direction of such inclination being such that the net can only be wound on to either shaft (9) so as to extend over the top thereof. The shaft assemblies (2 and 3) are further handed, to correspond with the direction of inclination of the hooks (19), so that they can respectively only be fitted at the left and right hand sides of the frame (4). For this purpose the two end fittings (10) are of different size, and the two crutches (5 and 6) which they respectively fit are also of correspondingly different size. <IMAGE>

Description

SPECIFICATION Net bed This invention relates to beds of the type in which a patient is supported on a flexible web of mesh or net form slung between two generally parallel shafts on to which the ends of the web are respectively wound. Such beds are particularly valuable in the prevention and treatment of bed sores and are hereinafter referred to generally as "net beds". They also facilitate the handling of supported patients as the shafts can be turned in the same direction to transfer the web from one shaft to the other, whereby a patient on the web is rolled over for repositioning thereon, or they can be turned in opposite directions to raise or lower the patient with respect to a conventional mattress or other support surface below the web.

Such net beds are in general use and the attachment of the ends of the web to a shaft presents problems. The attachment should be quick and simple but secure, and arrangements have been proposed which, generally speaking, provide security at the expense of ease and simplicity.

When winding on the web after attachment to a shaft it is important that it should go over the top of the shaft and not underneath it. In the latter case there would be a danger of the hand, for example, of a patient being trapped between the web and shaft whilst being raised or turned on the web. Present methods of attachment do not provide any protection against a web being wound incorrectly on to a shaft in the wrong direction by an unskilled or hurried operator. In our U.K. Patent Application No.

7931352 (Serial No. 2033739A)we have disclosed net beds the shaft assemblies of which incorporate a drive clutch/brake unit with a projecting drive shaft on which a winding handle is mounted. This unit operates, when the handle is not being turned, to brake the shaft against movement in one direction, i.e. the direction in which the weight of a correctly suspended patient would tend to turn the shaft. The shaft is free to turn in the other direction, and thus if a web is wound on incorrectly a raised patient would fall freely under gravity on release of the handles.

Hence, with this otherwise advantageous clutch/brake arrangement it is doubly important that the web should be wound on the shafts correctly.

According to the invention each shaft of a net bed has a series of retaining hooks spaced along the operative length of the shaft and of a size to engage the apertures in the mesh or net web to be wound on, the hooks being close to the surface of the shaft and directed to one side of the radial so that the web can only be hooked on and wound on to the shaft in one direction, the two shafts of the bed being handed both in respect of the direction of the hooks and so that they can only be fitted, respectively, in the left and right hand support crutches of a framework of the bed.

Preferably the retaining hooks are arranged in spaced groups, each group being formed on a retaining plate secured to the shaft surface. The group of hooks on each said plate is conveniently produced by a piercing and pressing operation, and the plate may be attached to a tubular shaft by blind rivets.

The web of the net bed is conveniently provided with three coloured stripes disposed laterally of the web, i.e. longitudinally of the bed - a stripe of one colour at the centre and two stripes of a different colour respectively spaced a short distance from the two ends of the web. The first stripe enables an operator to centralise the web between the shafts whereas each of the others provides a signal indicating that the web should not be unwound further from the corresponding shaft. If such stripes are not provided or an end stripe is ignored it is possible for a net to be unwound completely, thus allowing the patient to drop. To guard against this the web of a net bed in accordance with the invention may have an end sleeve or loop through which the corresponding shaft extends to hold the web captive.This is particularly advantageous with the hooks of the present invention as after the net has been completely unwound unwinding movement of the shaft can continue but the web and patient do not drop and the hooks disengage themselves to allow the shaft to turn freely in the sleeve or loop.

Each end of the net may have a permanent stitched sleeve through which the shaft has to be threaded when the web is fitted, but to avoid the necessity of this a temporary sleeve or plurality of short sleeve sections may be formed after the end has been attached. To this end the net may be hooked on to the hooked shaft of the invention some distance from its end, the free end portion being secured to the main section of the web by a flexible strip or rod threaded through the mesh or net of the web. A number of short lengths of rod, for example nylon rod of say 1/8" diameter, can be threaded through the web in this manner, providing a number of spaced sleeve sections along each end of the net.

The invention will now be further described with reference to the accompanying diagrammatic drawings which illustrate, by way of example, one embodiment of the invention. In the drawings: Figure 1 is an end perspective view of a complete net bed; Figure 2 is a fragmentary view of a shaft of the bed of Figure 1 embodying net retaining means in accordance with the invention, showing one way of securing the net; Figure 3 is a view showing the net being attached to a shaft; Figure 4 is a detailed view of a retaining plate shown in Figures 2 and 3; and Figure 5 is a sectional view on the line A-A in Figure 4.

The net bed illustrated comprises a flexible web 1 of mesh or net form, referred to herein as "the net", slung between two parallel winding shaft assemblies 2 and 3 on to which the ends of the net 1 are respectively wound as clearly shown in Figure 1. A collapsible support frame 4 which is mainly of tubu lar construction provides spaced support crutches 5 and 6 at one end of the frame and similarly spaced support crutches 7 and 8 atthe other end of the frame, in which crutches the adjacent ends of the shaft assemblies 2 and 3 are respectively supported.

The construction of the frame is as disclosed in our U.K. Patent Application No. 7931352 and will not be described in further detail herein.

The shaft assemblies 2 and 3, which are illustrated in fragmentary detail in Figures 2 and 3, each comprise a tubular shaft member 9 around which the corresponding end of the net 1 is wound and which extends between end fittings 10 and 11. Each end fitting 10 includes a winding handle 12 by which the shaft is turned through a drive clutch/brake unit 13.

The units 13 have a housing of square external profile so as to engage nonrotatably in the corresponding support crutches 5 and 6 which receive these units in rectangular crutch recesses.

The shaft assemblies 2 and 3 are handed in the sense that they can only be fitted, respectively, at the left-hand and right-hand sides of the frame 4. To this end the support crutch 7 (and one end fitting 11) is of different size to the other crutch 8 which fits the other end fitting 11. Each end fitting 11 comprises a stepped annular bearing member which rests in the corresponding supportcrutch 7 or 8 and provides a plain bearing allowing free rotation of the shaft when turned by the corresponding handle 12. The end fittings 10 and 11 of the shaft assemblies are also as described in detail in said Patent Application No.7931352, to which reference should be made if further detailed description is required.

The units 13 operate so thaa the handles 12 can be turned in either direction according to whether the net 1 is to be wound on or off the assemblies 2 and 3.

In one direction each unit 12 provides a clutch drive to wind on the net 1, whereas the assembly is normally braked against rotation in the other direction againstthe gravitational loading of the net 1 by a supported patient. Turning the handle 12 in the corresponding direction, i.e. to lower the patient, frees the brake of the corresponding unit 13 to allow such gravitationally produced rotation with a follow-up action. As the drive brake directions are different for the two units 13 it is essential for the assemblies 2 and 3 to be handed as has been described, so that they can each only be fitted on the correct side, and it will be appreciated that it is further essential for the net 1 to be wound on over the top of each shaft as shown in Figure 1 sothatthe braking action of each unit 13 opposes the gravitational loading.

The net 1 has a woven-in lateral stripe 14 of one colour which is positioned centrally along the length of the net to provide guidance for the operator in centralising the net 1 between the shaft assemblies 2 and 3: A short distance from each end the net also has a similar woven-in stripe 14 but which is of another colour to provide a signal, when one of these stripes appears, that the net should not be unwound any further off the shaft assembly concerned.

For retention of the attached net each tubular shaft, such as 9 in Figure 2, has attached thereto an axially aligned row of spaced retaining plates 15 each of which is secured to the tubular shafts by blind rivets such as 16 which engage rivet holes 17 in the plates, one ofwhich is shown in detail in Figures 4 and 5. Each plate 15 is manufactured by a piercing and pressing operation providing a curved profile 18 of the same radius asthe outer surface ofthetubularQ shafts 9 and a row offour spaced stepped hooks 19 which, when the plate is fitted, extends close to the surface of the corresponding shaft 9 and is directed to one side of the radial direction. Thus the net 1 can be hooked on to the shaft, so as to be retained by the hooks 19, in the manner shown in Figure 3.The necessity for the shaft assemblies 2 and 3 to be handed and forthe net 1 to be wound on over the top ofofthe shafts has already been explained, and it will be appreciated that the plates 15 must accordingly be fitted to the shafts so that the hooks 19 project in the correct directions, i.e. so that they act in the winding-on sense.

Figure 3 illustrates the net 1 being attached at an end edge to the corresponding retaining hooks 19, and in view of the unidirectional drive provided by these hooks it is desirable that the end of the net 1 should be captive on the shaft in case the net is fully unwound by an inexperienced or unattentive operator. It will be appreciated that this is only a safety measure and not essential, as the coloured stripe 14 adjacent the end should normally alert an operator. When the net is attached as in Figure 3 it may be provided with a number of end loops (not shown), for example four spaced loops, through which the corresponding shaft passes to prevent the net dropping off.

Figure 2 shows diagrammatically another way in which the same result can be achieved. In this case the net is attached to the hooks some distance from the end and is wrapped over the shaft and turned back on itself to provide a temporary end sleeve which is formed by short lengths of nylon rod, such as 19, which are threaded through the mesh of the two layers of net 1 at a number of positions across the width of the latter. This avoids the need to thread the shaft through attached end loops or a perma nentlystitched end sleeve, although the lattertype of sleeve or any otherarrangementwhich provides captivity of the end of the net while allowing continued rotation of the shaft in the unwinding direction may be employed.

Claims (11)

1. A bed of the type in which a patient is supported on a flexible web of mesh or net form, comprising two generally parallel shafts on to which the ends of the web are respectively wound and a framework presenting, ateach end of the bed, left and right hand support crutches for the two shafts, wherein each shaft has a series of retaining hooks spaced along the operative length of the shaft and of a size to engage the apertures in the mesh or net, said hooks being close to the surface of the shaft and directed to one side of the radial so that the web can only be hooked onto and wound on to the shaft in one direction, the two shafts being "handed" both in respect of the direction of the hooks and so that they can both be fitted, respectively, only in the correct ones of said left and right hand support crutches.

2. A bed according to claim 1, wherein the retaining hooks are arranged in spaced groups, each such group being formed on a retaining plate secured to the corresponding shaft surface.

3. Abed according to claim 2, wherein the group of hooks on each retaining plate is producer by a piercing and pressing operation.

4. A bed according to claim 3, wherein the shafts are tubular and each of the retaining plates is attached to the corresponding shaft by blind rivets.

5. A bed according to any one of the preceding claims, wherein said flexible web has three coloured stripes disposed laterally of the web, that is to say running longitudinally of the bed, namely a central stripe of one colour and two stripes of a different colour respectively spaced a short distance from the two ends of the web.

6. A bed according to any one of the preceding claims, wherein said web has end sleeves or loops through which the shafts respectively extend so that the web when unwound is retained captive thereof.

7. A bed according to claim 6, wherein a tempo -ary sleeve or plurality of short sleeve sections is formed at each end of the web after attachment to the corresponding shaft.

8. A bed according to claim 7, wherein each temporary sleeve or short sleeve section is formed by securing the free end portion of the web to the main section thereof by means of a flexible strip or rod threaded through the mesh or net of the web.

9. A bed according to any one of the preceding claims, wherein the shafts have end fittings which fit the respective support crutches and provide bearings in which the shaft turns to wind and unwind the web, the end fittings of the two shafts and the corresponding left hand and right hand support crutches being of different sizes.

10. A bed according to claim 9, wherein end fittings non-rotatably engage in the corresponding support crutches which they respectively fit, and each incorporate a drive clutch/brake unit which enable the shafts to be turned in either direction by means of end handles mounted on the-shafts, and operate as a brake to prevent unwinding movement of the shafts under the weight of a suspended patient when the handles are released.

11. A bed of the type in which a patient is supported on a flexible web of mesh or net form slung between two generally parallel shafts, constructed and arranged substantially as herein particularly described with reference to the accompanying drawings.