GB2050154A - Hospital beds - Google Patents

Abstract

An arrangement, e.g. for transferring a patient between a bed and a stretcher trolley, intended to be mounted on a bed having a mattress arrangement (3) and a sheet (24) or the like arranged to be placed on said mattress includes a pivotable (9, 13) sheet frame structure (15-19), detachably carrying (20-3) the sheet (24), whose pivotal movements when the sheet is swung from the mattress are controlled by a pivot arm mechanism (8, 11, 12). Arranged between the bed and the sheet frame structure is a spring mechanism (6). This comprises a gas spring (37, 40, 42) which can be locked in any desired position and which in a released position exerts a force such as to substantially balance the weight of a patient resting on the sheet during swinging. The spring mechanism also includes a spring means (59), e.g. a compression spring, which is coupled in series with the gas spring via latching means (50, 51, 52). The latching means are arranged to release the spring means (59) when the sheet is partly relieved of the patient's weight on reaching a position A partially contacting the mattress and when the gas spring is locked, spring (59) permitting further swinging of the sheet towards the mattress to a position B in which it can be released from the frame structure. <IMAGE>

Description

SPECIFICATION An arrangement in sick beds The present invention relates to an arrangement for mounting onto a sick bed having a mattress arrangement including a flexible sheet placed on the mattress, said sheet being releasably attached at its ends to a sheet frame-structure pivotally arranged on the bed and incorporated in the foot and head boards or/and members thereof, the pivoting movement of said sheet frame-structure being controlled by at least one pivot-arm mechanism.

Such sheet frame-structures, which enable a patient lying on the sheet to be moved from the sick bed to, for example, a stretcher trolley located adjacent the bed, greatly facilitate the heavy task of moving the patient. One disadvantage with such frame structures, however, is that a large force must be applied to the frame structure in order to move the same, and that this force must be continued during the whole of the movement, so that the patient is not, for example, dropped down onto the bed. Attempts have been made to incorporate, for example, hydraulic motors or electric motors for driving the frame structure during its pivoting movement, but such arrangements are expeiisive and often prevent the sick bed from being moved freely.One disadvantage with the use of hydraulically operated frame structures is that oil often leaks out, causing the floor to become slippery.

It is therefore an object of the invention to provide a simple and relatively inexpensive arrangement which enables movement of a patient lying on the sheet to be fully controlled without requiring strenuous effort on the part of the personal involved in moving the sheet frame-structure.

To this end there is used a gas spring of a known kind which, when the sheet, and therewith the sheet frame-structure, is subjected to the weight of a patient, substantially counteracts the weight of said patient both during the upward part and the downward part of the swinging movement between the sick bed and an operating table or the like located adjacent the bed. The gas spring is conveniently a lockable gas spring of the kind sold by the German company Stabilus GmbH under the trade name Bloc-O-Lift. This gas spring has arranged in the piston thereof a control valve which can be activated by means of a control rod projecting outwardly from one end of the cylinder of the gas spring.One problem with a gas spring of this kind, which counteracts the weight of the patient, is that it can not be used at that moment when part of the body of the patient comes into contact with the mattress via the then arcuately hanging sheet. When contact is established between the patient and the aforementioned sheet, the tension in the sheet is also reduced and the force acting on the spring becomes too small to maintain a balance. Consequently, in order to lower the sheet further it is necessary for the nurse or operator to press the frame structure downwardly until the sheet is slack, so that the ends of the sheet can be released from the frame structure and the patient can lie in a normal position on the bed.This problem is solved in accordance with the invention by the fact that a spring arrangement is coupled in series to the powerful gas spring, which has a force of, for example, 1000 Newtons. This spring is prevented from coming into operation when the frame structure takes up the whole of the weight of the patient, by means of latching means. The gas spring is not locked until the patient comes into contact with the sheet, and the latching means are released by means of a light pressure on the frame structure, and the spring arrangement comes into operation and permits the sheet and the patient to be gently lowered to a final position in which the sheet can be released from the sheet frame-structure.

The essential characterising features of the invention are disclosed in the claims and an embodiment of the invention will now be described with reference to the accompanying drawings, in which Figure 1 illustrates in a simplified manner a sick bed provided with an arrangement according to the invention.

Figure 2 illustrates a detail of the sheet frame-structure, Figure 3 is a sectional view taken on the line Ill-Ill in Fig. 2, Figure 4 illustrates the gas spring, the spring coupled thereto, and the means cooperating therewith, and Figure 5 illustrates a modified pivot-arm mechanism.

The sick bed illustrated in Fig. 1 has a first end member, e.g. a head board 1 and a second end member 2, e.g. a foot board, between which there is arranged a mattress arrangement 3. Although in the illustrated embodiment the end members have the form of solid sheets of material, they may have any suitable form and may, for example, comprise tubes which have been welded together. In the illustrated embodiment there is arranged on one longside of the bed a fixed bar 4, said bar being fixed to the bed by means of elements not shown. The end member 1 has an attachment means 5 for a spring mechanism 6, said mechanism being described in more detail hereinafter.The attachment means 5 forms a pivot means around which the spring mechanism 6 can be freely rotated, and is capable of being displaced vertically in a slide 5' and locked in selected positions therealong, to enable the torque of the spring mechanism acting on the parallel arm mecha nism to be altered.

The other end of the spring mechanism 6 is connected to a pivot means 7 arranged on an arm 8 forming part of a parallel arm mechanism. The other end of the arm 8 is pivotally mounted on a pivot shaft 9, which is fixedly mounted on the end member 1. The other end of the arm 8 is pivotally connected to a pivot 10 on one end of an arm 11, said arm 11 forming a connecting arm in a parallel arm mechanism. The other pivot arm of the parallel arm mechanism is referenced 1 2. As will be seen from the drawing, one end of the pivot arm 1 2 is pivotally journalled to the fixed bar 4 at 13, while the other end of said arm 1 2 is pivotally journalled on the connecting arm 11 at 14.The arms 8, 11 and 12 form a parallel-arm mechanism and when the arms 8 and 1 2 are pivoted the connecting arm 11 will be moved parallel with itself, due to the fact that the distance between the pivot points 9 and 10 is equal to the distance between the pivot points 1 3 and 1 4. Further, the distance between the pivot points 9 and 1 3 coincides with the distance between the pivot points 10 and 14 and the respective connecting lines are parallel with one another.

When the arms 8 and 1 2 are pivoted around the points 9 and 13, the arm 11 will consequently move parallel to itself. Connected to the arm 11 is an arm 1 5 which in the illustrated embodiment is substantial vertical and which merges with a vertical arm 1 7 via an intermediate arm 1 6. The arms 1 5 and 1 7 thus form, together with the arm 16, a bifurcate structure which encloses the end member 1. The other end member 2 is provided with an identical parallel-arm mechanism, and optionally also with a spring mechanism 6. Connected between the vertical arms 1 7 at the two end members 1 and 2 is a beam 1 8 by which the two parallel arm mechanisms are firmly connected with one another.The vertical arms 1 7 carry at their lower ends, located inwardly of respective end members 1 and 2, a horizontal end piece 1 9. Each of the end pieces 19, which have the form of a beam extending parallel to the plane of the mattress arrangement 3, are provided in the illustrated embodiment with hooks 20, 21, 22 and 23 (Fig. 3), arranged to engage in holes in a sheet 24 on which the patient is intended to rest. The sheet 24, which may comprise a plastics material, a textile material or an underlay which is flexible in at least the long direction of the bed, shall be released from the end pieces 1 9 when the patient is lying on the bed, and lie loose on the mattress 3.

In Fig. 1, the end pieces 19 are showed in a partially lifted position A, in which the sheet 24 when a patient is resting thereon partially provides contact with the mattress 3, which thus takes up the weight of the patient. The sheet 24, however, is so tensioned that it can not be removed from the hooks 23. In the position A it is not possible for the sheet frame structure, and therewith also the end pieces19, to be further lowered without pressing down, for example, the beam 1 8 with a large force, owing to the fact that a gas spring in the spring mechanism exerts a force which substantially corresponds to the weight of the patient.Consequently in order to enable the sheet to be lowered to a position B in which said sheet can be released, the spring mechanism is constructed in a manner which will now be described with reference to Fig.

4.

In Fig. 4 there is illustrated an attachment means 25 which is intended to co-operate with a shaft pivot in the pivot 7, and a further attachment means 26 arranged to co-operate with a shaft pivot in the pivot 5. The attachment means 25 has the form of a sleeve 27 provided with an outwardly projecting bracket means 28 forming an attachment for an operating cable 29 of conventional type. The cable 29 has an inner, flexible operating wire 30 which can be displaced by means of an operating means 31 indicated in Fig. 1. The operating wire 30 may be made of steel or some other suitable material, and the end of said wire projecting from the cable 29 is connected to an operating or lever arm 32 which is pivotable about a shaft 33. The shaft" 33 is mounted in a groove 34 in the sleeve 27 and is fixed to the wall of the groove. The sleeve 27 is screw-threaded on a guide sleeve 35.Fixedly mounted on the upper end of the guide sleeve 35 is a plug 36 into which the free end of a piston rod 37 is screwed and firmly locked by means of nuts 38, 39. The piston rod 37 is of hollow tubular construction and carries at its inner end a piston 40 which is arranged to co-operate with the inner wall 41 of a gas-spring cylinder 42. The cylinder 42 is sealed against the piston rod 37 and its lower end 43 is closed by a bottom plate.

Arranged in the hollow piston rod 37 is a rod 44 whose upper end projects above the plug 36 and coacts with the free end 45 of lever arm 32. The lower end of the rod 44 is provided with a valve body 46 arranged to coact with the seating of a through-flow opening (not shown) in the piston 40. In Fig. 4 the valve 46 is shown in its closed position and the cylinder 42 and the piston rod 37 are firmly locked together. When the lever arm 32 is rotated clockwise in Fig. 4, the rod 44, due to tension created in the wire 30, will be moved downwardly and the valve opened, wherewith gas flows between the two working chambers 47 and 48 of the gas spring.

Mounted for free axially sliding movement in the guide sleeve 35 is a spring sleeve 49 in which the cylinder 42 is axially slidable. In the illustrated embodiment, the spring sleeve 49 is provided with a latching means comprising two cylindrical latching plungers 50, 51 having a compression spring 52 arranged between the mutually facing end surfaces thereof. The outer ends of the latching plungers project out through two mutually opposite holes (not shown) in the spring sleeve 49.

These outer ends of the plungers are each provided with camming surfaces 53 and 54 respectively, arranged to co-operate with respective camming surfaces 55, 56 on the lower peripheral edge of the guide sleeve 35.

The two latching plungers 50, 51 extend freely in the holes in the spring sleeve 49 and are connected to respective ends of the compression spring 52. To prevent the latching plungers from sliding out of the spring sleeve, there is provided suitable holding means, such as a sleeve, which encircles the lower end of the guide sleeve 35 and covers the outwardly projecting ends of the plungers 50, 51.

The plungers 50, 51 abut a pressure plate 57 which is freely displaceable in the spring sleeve 49. Arranged between the pressure plate 57 and a fixed plug 58, which is screwthreaded in the lower end of the spring sleeve 49, is a compression spring 59 the force exerted by which will substantially permit only the weight of the sheet frame-structure to be balanced. The force exerted by the spring may, for example, be 1 50 Newtons.

The bottom plate 43 of the gas spring abuts the latching plungers 50, 51 in the illustrated embodiment. When the sheet frame-structure is to be swung out from the position shown in Fig. 1 with a patient lying on the sheet 24, the spring mechanism occupies the position shown in Fig. 4. The operator activates the operating means 31 by, for example, depressing a handle (not shown), thereby displacing the operating wire 30 and rotating the lever arm 32 clockwise, whereat the rod 44 is moved downwardly and the valve 46 opened. It should be mentiond that the working surface of the piston 40 facing the chamber 48 is greater than the active surface of the other side of the piston 40, so that the piston 40 will move upwardly in Fig.

4. The piston rod 37 is moved out of the cylinder 42 and the guide sleeve 35 and the attachment means 25 will be moved upwardly and the arm 8 (Fig. 1) rotated clockwise. The whole of the sheet frame-structure with the sheet 24 and the patient lying thereon will thus be swung out from the mattress 3.

Depending upon the force exerted by the gas spring and the weight of the patient, the operator will either need to brake or facilitate the movement, using but a negligable force, although under all circumstances the work required of the operator will be very light. If, for some reason or other, the swinging movement must be interrupted, e.g. because the patient is nervous or moves, the operator releases the operating means 31 causing the valve 46 to close. The operating handle is of the 'dead-mans' grip type, i.e. the operating means must be actuated directly in order for the gas spring to be released.

During continued pivoting and swinging movement, the pivots 10 and 14 pass the upper point of the pivot arc and the pressure force exerted by the frame structure and the patient is counteracted by the gas spring, since the piston rod 37 is forced into the cylinder 42. Finally, the sheet 24 with the patient lying thereon is brought into contact with a stretcher trolley (not shown) located adjacent the bed, and as contact of the patient with the stretcher increases, the force exerted by the frame structure on the piston rod 37 will decrease. This means that the operator must apply a large force which at maximum corresponds to the force exerted by the gas spring, in order that the sheet lies so flat that the load thereon is releaved and the sheet can be released from the hooks 20-23 on respective end pieces 19. It is not possible for a single operator to produce the force required.This problem, however, is solved by the spring mechanism according to the invention.

It will be assumed here that the patient is swung back to the sick bed, to be placed on the mattress 3. The sheet 24 with the patient resting thereon is finally located in the position illustrated in Fig. 1, the end pieces 1 9 taking the position A. A large part of the patient's weight is then taken on the mattress 3, although the sheet 24 is still stretched to an extent such that the ends of the sheet cannot be lifted from the hooks 20-23. The spring mechanism has the position shown in Fig. 4 and the operating means 31 is no longer activated. The valve 46 is closed and the piston 40 is locked in its position.In order to move the end pieces 1 9 to the position B shown in dashed lines in Fig. 1, the operator presses down the frame structure with his or her hands and the spring sleeve 49 will then be moved into the guide sleeve 35. The camming surfaces 53 and 54 of the latching plungers 50 and 51 co-operate with the camming surfaces 55 and 56 of the guide sleeve to press the plungers towards each other. During continued movement of the spring sleeve 49 into the guide sleeve 35, the lower camming surfaces 53' and 54' respectively of the plungers 50, 51 will guide the latching plungers completely into the spring sleeve and be pressed downwardly by the locked gas spring and against the action of the compression spring 59. As before mentioned, the force required is relatively small and corresponds, for example, to the weight of the frame structure.Subsequent to moving the end pieces 1 9 to the position B, the sheet 24 can be released and the patient can rest in a normal position on the mattress 3.

Illustrated in Fig. 1 is a beam 67 which can be swung in beneath the beam 1 8 and out therefrom. In the outwardly swung position shown in Fig. 1, lines 68 and 69 can be placed on the ends of the beam and on the edges of the sheet 24 to further stabilize said sheet during movement of the patient.

The aforedescribed, specific embodiment of the invention can be modified in many ways.

Thus, it is not necessary to use a parallel-arm mechanism of the kind illustrated. As an example of a modified embodiment, reference is made to Fig. 5. This Figure illustrates one end of a bed in which the bed end member 1 is of a conventional type and comprises tubes which have been welded together. The bar 4 is fixedly mounted by means of bracket structures 60 on the fixed lower part of the bed. In this embodiment, the pivot arm mechanism has the form of two arms 61 and 62 which are fixedly connected together, and the spring mechanism 6 is of the aforedescribed embodiment. Thus, the pivot arm will pivot about a point 63 on the bar 4 and a point 64 on the sheet frame-structure and movement of said arm is activated by the spring mechanism 6, which is connected at its end points to the pivot point 65 on the bed and to the pivot point 66 on the arm 62.

The illustrated and preferred spring arrangement 57, 58, 59 can be replaced with a nonlockable gas spring of conventional kind.

Although in the illustrated embodiment the sheet 24 has been shown to be hung on hooks, it will be understood that other releasable attachment means can be used.

Claims (7)

1. An arrangement for mounting onto a sick bed having a mattress arrangement, including a sheet or a like flexible undersheet which can be placed on the bed, which sheet is releasably connected at its ends to end pieces forming part of a sheet frame structure pivotally arranged on said bed, the pivot movement of which frame structure is controlled by at least one pivot arm mechanism wherein arranged between the bed and the sheet frame structure is a spring mechanism having a gas spring with a piston rod which is arranged to be locked in a desired position relative to the cylinder and to be released for movement relative to the cylinder by means of manually actuable operating means, and which gas spring in the released state of the piston rod is arranged to exert such a force that the weight of a patient lying on the sheet is substantially balanced when swinging the sheet frame structure between a first position, in which the sheet lies inwardly swung over the mattress, and a second position in which the sheet lies outwardly swung on the mattress, the sheet in both positions carrying the whole weight of the patient, and in which the spring mechanism further includes a spring means which is coupled in series with the gas spring over latching means, said latching means being arranged, when the sheet frame structure is swung between the two said positions, to hold the spring means is an inoperative state, and, when the sheet reaches the mattress and the weight of the patient is partly releaved and the gas spring is locked by means of the manually actuable operating means, to permit further swinging of the sheet towards the mattress to a position in which the sheet can be released from the end pieces.

2. An arrangement according to claim 1, wherein the spring means comprises a compression spring.

3. An arrangement according to claim 1, wherein the end pieces are provided with hooks to co-act with openings in both end portions of the sheet.

4. An arrangement according to claim 2, wherein the cylinder of the gas spring is slidably mounted in a spring sleeve which is, in turn, slidably mounted in a guide sleeve whose one end is provided with a first attachment means for the spring mechanism and forms an attachment point for the piston rod of the gas spring; that the spring sleeve is provided on the end part thereof projecting outwardly from the guide sleeve with a further attachment means; and in that the latching means are arranged between the spring sleeve and the guide sleeve thereby to form a support for the cylinder of the gas spring; and in that said compression spring is arranged between the latching means and said further attachment means.

5. An arrangement according to claim 4, wherein the latching means comprise radially displaceable latching plungers which project outwardly through openings in the wall of the spring sleeve and which are arranged to be urged away from each other by means of a spring means arranged therebetween; and in that the ends of said latching pegs projecting from the outer wall of the spring sleeve are arranged to abut the free edge of the guide sleeve.

6. An arrangement according to claim 5, wherein said ends and said free edge have mutually co-acting camming surfaces.

7. An arrangement for mounting onto a sick bed substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.