Driveable transport means, in particular a transport trolley or hospital bed

Abstract

The present invention relates to a transport means (18), in particular a transport trolley (17) or hospital bed (1), provided with a moveable frame (2), which frame (2) comprises four wheel supports (4) which are pivotably mounted on the frame (2) in the corner regions of the frame (2), wherein each wheel support (4) comprises a wheel (5) which is connected to the wheel support (4) rotatably about a wheel axis, wherein the transport means further comprises a drive wheel (6) which is mounted within the periphery of the frame (2) and is rotatable about a wheel axis, wherein the transport means comprises drive means configured to rotate the drive wheel (6) about its wheel axis, wherein the transport means comprises a drive wheel support (7) which is rotatably connected to the frame (2) and to which the drive wheel (6) is rotatably connected, and wherein the frame (2) comprises means configured to exert a downward force on the drive wheel support (7) so that the drive wheel (6) remains in constant contact with the ground surface over which the transport means is displaced.

Description

[0001] The present invention relates to a transport means provided with a moveable frame, which frame comprises four wheel supports which are pivotably mounted on the frame in the corner regions of the frame, wherein each wheel support comprises a wheel which is connected to the wheel support rotatably about a wheel axis, wherein the transport means further comprises a drive wheel which is mounted within the periphery of the frame and is rotatable about a wheel axis, wherein the transport means comprises drive means configured to rotate the drive wheel about its wheel axis. The present invention relates in particular to a transport means in the form of a transport trolley or hospital bed.

[0002] Within the context of the present invention, the term "hospital beds" should be understood to mean hospital beds, nursing beds, stretchers, care chairs and the like. Within the context of the present invention, the term "transport trolley" should be understood to mean a transport cart, mobile cart, trolley, pallet cart and the like.

[0003] A hospital bed is specially designed to allow patients to lie comfortably and safely and to aid care providers in their work. The bed is often made of sturdy metal or plastic and stands on pivotable wheels (wheel supports), with the result that it can be displaced easily through the hospital.

[0004] The mattress of a hospital bed is usually made of a medical foam or another material that is comfortable but also suitable for long periods of lying and helping to prevent bedsores. The lying surface is often adjustable so that care providers (or the patients themselves) can adjust the lying surface and bed height using an electrical hand control or manual levers. Some beds also have side rails which can be raised in order to prevent the patient from falling out.

[0005] In order to facilitate the transport of patients within hospitals and to reduce the physical strain for care providers, it is known to provide within the periphery of the frame an additional (auxiliary) wheel which is arranged centrally and driven electrically. The driven wheels often have an automatic braking function or a "dead man's switch" which ensures that the beds only move when the care provider presses and holds a switch. This prevents uncontrolled rolling of the bed.

[0006] The fifth (auxiliary) wheel in question is retractable. Retractable auxiliary wheels are moveable between a lowered, folded-out position (driving position), in which it is rotatable only about its wheel axis, and a raised, retracted (stowed) position. In the driving state, the retractable auxiliary wheel is lowered so that it makes contact with the ground surface (the floor), the wheel is driven and it is possible to move the hospital bed only rectilinearly. In some cases, however, it is better to lift the auxiliary wheel off from the ground and put it in the stowed position, in order to for example place the bed laterally in the correct position. When the central (additional) wheel is in the retracted position, it is specifically possible to displace the hospital bed in all directions. Providing the hospital bed with a centrally positioned fifth wheel makes it possible to displace the bed through corridors with minimal effort, even if a patient is lying thereon.

[0007] A disadvantage of the centrally positioned drive wheel that is able to be folded in and out is that it is a complex and expensive system. In addition, the wheel has to be folded in to displace the hospital bed in a different direction. The object of the present invention is therefore to provide an alternative driveable hospital bed, and by extension a transport means which is user-friendly, has a simpler construction and can be easily displaced in all directions.

[0008] American patent publication US 6,390,213 B1 describes a manoeuvrable self-propelled trolley, such as a hospital bed, having castors which operate independently of each other, are mounted in corner regions and can rotate 360°, and a drive unit which is mounted within the periphery of the trolley frame and consists of a rotatable drive wheel carriage having at least two drive wheels which propel the trolley over rough or uneven surfaces. An operator can propel and control the trolley using a joystick control. The trolley in question also comprises means configured to exert a downward force on the drive wheels so that they remain in constant contact with the ground surface over which the hospital bed is displaced. The drive wheel carriage can rotate with respect to the frame of the trolley about a virtually vertical axis. In this way, the trolley can be propelled along both the longitudinal axis and the transverse axis, as a result of which the trolley is easier to manoeuvre in small spaces. In order to prevent the drive wheel carriage from unintentionally deviating from its alignment along the longitudinal axis of the trolley, a locking mechanism is provided which is operated via a lever. A reversible motor can be coupled to each drive wheel. This motor can rotatingly drive the drive wheel in order to displace the trolley or to rotate the drive wheel carriage.

[0009] The object of the invention is achieved by providing a transport means, for example a transport trolley or hospital bed, provided with a moveable frame, which frame comprises four wheel supports which are pivotably mounted on the frame in the corner regions of the frame, as described in Claim 1. Due to the fact that the drive wheel makes constant contact with the ground surface and the transport means is configured in such a way that it can rotate around the drive wheel support, the transport means can be easily displaced in a desired direction. In particular, the drive wheel support is positioned centrally within the periphery of the frame. In contrast to the known solutions, the drive wheel will never be raised to a position in which it no longer contacts the ground surface.

[0010] Said wheels and said drive wheel are arranged rotatably about their respective wheel axis in order to move the transport means. The wheel axes in question are thus the axes that allow the wheel, and thus also the transport means, to move on the underlying surface. These wheel axes are horizontal axes which preferably extend parallel to the underlying surface on which the transport means rests.

[0011] In a particular embodiment of the transport means according to the invention, the transport means comprises a hingeable arm which is connected to the drive wheel support and rotatably connects this drive wheel support to the frame. More particularly, said means are sprung means, which sprung means for example comprise a torsion spring, coil spring or gas spring which is configured to exert a, preferably sustained, downward force on the hingeable arm. The hingeable arm will hinge about a hinge axis. This axis extends as such, for example parallel to the ground surface and transversely to the longitudinal direction of the transport means. The hinge axis does not have to extend in the above way, for instance in an alternative embodiment the hinge axis may extend parallel to the ground surface and parallel to the longitudinal direction of the transport means, and also other arrangements of the hinge axis, such as an oblique arrangement, are possible. Due to the hingeable axis, the hingeable arm can move back and forth, in order to in this way compensate for any unevennesses in the ground surface, or inclinations, and in order to avoid an abrupt impact when crossing, for example, a threshold. A hingeable arm designed in this way ensures that the drive wheel continues to remain in constant contact with the ground surface.

[0012] According to the invention, each wheel support is arranged rotatably about a respective rotational axis in order to change the displacement direction of the wheels, the drive wheel support is arranged rotatably about a rotational axis in order to change the displacement direction of the drive wheel, and the transport means comprises a brake system which is adjustable between at least three positions, being a braking position, in which rotation of at least one of said wheels about their respective wheel axis is prevented, a rotation position, in which said wheels are rotatable about their wheel axis and rotational axis, and a direction-fixing position, in which said drive wheel is rotatable about its wheel axis in order to move the transport means and the rotation of said drive wheel support about said rotational axis is prevented. In the direction-fixing position, all said wheels, i.e. the four wheels of the wheel supports and the drive wheel, are rotatable about their respective wheel axis.

[0013] Said axis about which the drive wheel support is rotatably arranged is the axis which ensures that the driving direction of the drive wheel is changeable. This axis is, for example, a vertical axis which extends perpendicularly to the underlying surface on which the transport means rests. Preventing the rotation about this rotational axis allows the transport means to be moved rectilinearly more easily. This is referred to as fixing the driving direction in the direction-fixing position. The wheel supports with the wheels are also arranged pivotably about a respective, vertically extending rotational axis, with the result that they can be oriented in the same direction as the drive wheel support.

[0014] To prevent the rotation of at least one of said wheels about its wheel axis, the brake system comprises a first brake device. In particular, this first brake device is provided to prevent the rotation of at least three, and preferably all, of said wheels about their respective wheel axis. The first brake device comprises, for example, a brake shoe which can be pressed onto the respective wheel, or this first brake device comprises tooth-shaped elements which can engage in each other, as a result of which, in the engaged state, the wheel can no longer rotate. The brake system further comprises a second brake device suitable for preventing the rotation of the drive wheel support about said rotational axis.

[0015] In a particular embodiment of the transport means according to the invention, in said rotation position, the drive wheel support is freely rotatable about its mentioned rotational axis in order to change the displacement direction. This allows the transport means to be manoeuvred in the desired direction. For example, in said direction-fixing position, the drive means are activated in order to rotate the drive wheel about its wheel axis to assist the displacement of the hospital bed. In a possible embodiment, the drive means make use of sensor-controlled assistance, wherein the drive motor, which forms part of the drive means, delivers proportional power on the basis of the measured pushing force on the transport means. The drive wheel may be rotated in motorized fashion both in the forward direction and in the rearward direction. The drive means comprise, for example, an electric motor as drive motor.

[0016] More particularly, the transport means according to the invention comprises a brake pedal for adjustment of the various positions. The brake pedal offers the advantage that the brake system can be activated in a single movement. Via the brake pedal, it is therefore also possible to activate the drive wheel to assist the displacement movement of the transport means, with the result that an additional operating element is no longer required to activate the drive wheel. In a possible embodiment, the transport means then also comprises a suitable transmission mechanism which is connected to at least three, preferably all, of the wheels so that the adjustment of the position is transmitted to the appropriate brake device. This transmission mechanism may, for example, comprise multiple rods. In the case of the transport means according to the invention, at least one of the wheel supports, preferably all of the wheel supports, and the drive wheel support are mechanically coupled to each other. For the coupling to each other, the transport means comprises a number of connecting rods which form part of said transmission mechanism. In an alternative embodiment, the adjustment of the various positions mentioned may also be activated electronically.

[0017] In a most particular embodiment, the transport means is a hospital bed provided with a lying surface, which is height-adjustable with respect to the frame, for a patient. In an alternative embodiment, the transport means is a transport trolley.

[0018] In order to further illustrate the properties of the present invention and to indicate additional advantages and particular features thereof, a more detailed description of the transport means according to the present invention will now be given. It will be clear that nothing in the following description may be interpreted as a limitation of the protection for the present invention as laid down in the claims.

[0019] In the present description, reference numerals are used to refer to the attached drawings, in which: Figure 1 is a perspective illustration of a transport means in the form of a hospital bed according to the invention; Figure 2 is a detail illustration of the centrally positioned drive wheel; Figure 3 shows a top view of the illustration depicted in Figure 2; Figure 4 is a perspective illustration of a transport means in the form of a transport trolley according to the invention; Figure 5 shows a top view of a possible embodiment of a transport means according to the invention; Figure 6 shows a side view of a transport means positioned on a flat ground surface, wherein the brake system of the transport means is set via the brake pedal to the rotation position; Figure 7 shows a side view of a transport means positioned on a ground surface with a depression in such a way that the drive wheel is positioned at a lower level than the corner wheels, wherein the brake system of the transport means is set via the brake pedal to the rotation position; Figure 8 shows a side view of a transport means positioned on a ground surface with a hump in such a way that the drive wheel is positioned at a higher level than the corner wheels, wherein the brake system of the transport means is set via the brake pedal to the rotation position; Figure 9 shows a side view of a transport means positioned on a flat underlying surface, wherein the brake system of the transport means is set via the brake pedal to the braking position; Figure 10 shows a side view of a transport means positioned on a flat underlying surface, wherein the brake system of the transport means is set via the brake pedal to the direction-fixing position.

[0020] In a first preferred embodiment, the transport means (18) according to the present invention is designed as a hospital bed (1) (item of hospital furniture) and is depicted in Figure 1. The hospital bed (1) is configured for carrying patients and is constructed from a moveable frame (2) and a lying surface (3), which is height-adjustable with respect to the frame, for a patient. To adjust the height of the lying surface (3), the hospital bed (1) comprises a setting mechanism (12) configured for this purpose.

[0021] The frame (2) of the transport means (18) is the supporting structure and is constructed, as inter alia apparent from Figures 1 and 5, from two longitudinal profiles (13) which extend parallel to each other and are connected to each other via two transverse profiles (14). The frame (2) also comprises four (corner) wheels (5) (also called castors) which are each mounted pivotably via a respective wheel support (4) on the frame (2), in a respective corner region of this frame (2). Each wheel (5) is rotatable about a horizontal wheel axis in order to move the frame (2). The various wheel supports (4) are pivotable about a vertical rotational axis (pivot axis) in order to in this way place the wheels (5) in the desired position so that the hospital bed (1) can be displaced in the desired direction.

[0022] Mounted within the periphery of the frame (2), preferably at a central position, is a drive wheel support (7) which is connected to the frame (2) rotatably about a vertical rotational axis (10) and in which a drive wheel (6) that is rotatable about a horizontal axis is fitted. The frame (2) further comprises drive means, for example in the form of a drive motor such as an electric motor, in order to be able to rotate the drive wheel (6) in motorized fashion. The electric motor is supplied with power by an energy source, such as a battery. The drive means are configured to rotate the drive wheel (6) to assist the displacement movement of the hospital bed (1), and to do so in the forward or rearward direction at a specific speed. More specifically, the drive means offer sensor-controlled assistance, wherein the drive motor delivers proportional power on the basis of the measured pushing force on the transport means (18). In practice, the drive means are configured to offer assistance as follows: when the transport means (18), for example the hospital bed (1), is pushed harder, the drive wheel will rotate more rapidly, and when the hospital bed decelerates more, the drive wheel will rotate less rapidly (slow down more). Such a centrally positioned motorized drive wheel (6) increases the controllability of the hospital bed.

[0023] Furthermore, the frame (2) is configured to, as illustrated in Figure 2, exert a sustained downward (pressing) force on the drive wheel support (7) (and thus also the drive wheel) in order to urge the drive wheel (6) to remain in constant contact with the ground surface (19), even when the hospital bed (1) drives over a hump (see Figure 8) or a depression in the ground surface (19) (see Figure 7), accelerates or decelerates, or when transitioning from a horizontal underlying surface to an inclined underlying surface, or when transitioning from an inclined underlying surface to a horizontal underlying surface. To exert the downward pressure, the hospital bed (1), and by extension the transport means (18), comprises, as illustrated in Figures 2, 3 and 5 to 10, a hingeable arm (8) on which a torsion spring (or a coil spring or gas spring) acts. The torsion spring ensures that a virtually constant downward pressure is exerted on the drive wheel (6). The hingeable arm (8) connects the drive wheel support (7) to the frame (2) and comprises a first end to which the drive wheel (6) is connected via the drive wheel support (7), and a second end which is hingeably mounted about a hinge axis on a fastening element, for example a mounting bracket, of the frame (2). The hingeable arm (8) will hinge about this hinge axis. This axis extends as such, preferably parallel to the ground surface (19) and transversely to the longitudinal direction of the hospital bed, with the result that the hingeable arm (8) can move back and forth in the direction (A) indicated in Figure 2, in order to in this way compensate for any unevennesses in the ground surface, or inclinations, and in order to avoid an abrupt impact when crossing, for example, a threshold.

[0024] As indicated above, the drive wheel support (7) is arranged rotatably about a vertical rotational axis (10) in order to change the displacement direction of the drive wheel (6), as illustrated in direction (B) in Figure 3. The hospital bed (1), and by extension the transport means (18), further comprises a brake system which is adjustable between at least three positions, being a braking position, in which rotation of at least one of said wheels, namely the (corner) wheels (5) and the drive wheel (6), about their respective wheel axis is prevented, a rotation position, in which said wheels (5; 6) are rotatable about their wheel axis and their respective rotational axis, and a direction-fixing position, in which the wheels (5) and said drive wheel (6) are rotatable about their respective wheel axis in order to move the hospital bed and the rotation of said drive wheel support (7) about said rotational axis (10) is prevented. Preventing the rotation about this rotational axis (10) allows the hospital bed (1) to be moved rectilinearly more easily. This is referred to as fixing the driving direction in the direction-fixing position. In particular, in the direction-fixing position in question, the wheel supports (4) with the wheels (5) also remain pivotable about their respective, vertically extending rotational axis (pivot axis), with the result that they can be oriented in the same direction as the drive wheel support (7). In the braking position, the rotation of at least one wheel, preferably all the wheels (5; 6), is prevented, as a result of which the moving of the hospital bed (1) is prevented and the patient can for example safely get onto or off of the hospital bed.

[0025] The brake system is activated using a brake pedal (11). In the embodiments depicted, a brake pedal (11) is provided on each longitudinal side of the transport means (18). The brake pedals (11) are positioned opposite each other. The central brake system (transmission system) consists of rods which connect at least three of the five wheels, and for example all five wheels. As illustrated in Figure 5, there are, for example, two transverse connecting rods (20) which respectively connect the front (castor) wheels (5) and the rear (castor) wheels to each other, and a longitudinal connecting rod (21) which couples the transverse connecting rods (20) to each other in order to in this way transmit the movement (direction) of the front wheels to the rear wheels, or vice versa, as a result of which all the wheels are in the same position, being the braking position, the rotation position or the direction-fixing position. The longitudinal connecting rod (21) will act on a moveable brake arm (15) connected to a brake cam (16) which is configured to prevent rotation of the drive wheel support (7) about the rotational axis (10). Depending on the position of the brake pedal (11), the wheels can, via these connections, be placed simultaneously in positions described above, namely: wheels braked (braking position); wheels freely moveable both in the rotational direction and rolling direction (neutral position or rotational positions); one wheel is secured in the driving direction (= wheel with directional lock) while the other wheels are completely free. This ensures that a rectilinear path can be easily travelled (directional position or direction-fixing position). In the direction-fixing position, the assisting driving function of the drive wheel will be activated. Securing the driving direction of the drive wheel (6) also ensures that the hospital bed (1) is easier to steer, as a result of which the user's back is subjected to less strain.

[0026] To prevent the rotation of at least one of said wheels about its wheel axis, the brake system comprises a first brake device. Preferably, this first brake device is provided to prevent the rotation of at least three, and more preferably all, of said wheels about their respective wheel axis. The brake system further comprises a second brake device suitable for preventing the rotation of the drive wheel support (7) about said rotational axis (10). This second brake device comprises, inter alia, a moveable brake arm (15) which actuates a brake cam (16). The brake cam will prevent rotation of the drive wheel support (7) about the rotational axis (10).

[0027] In the rotation position, the drive wheel support (7) is freely rotatable about said rotational axis (10) in order to change the displacement direction. This allows the hospital bed to be manoeuvred in the desired direction. In said direction-fixing position, the drive means are activated in order to rotate the drive wheel about its wheel axis to assist the displacement of the hospital bed (1).

[0028] In a second preferred embodiment, the transport means (18) according to the present invention is designed as a transport trolley (17). Such a transport trolley (17) is depicted in Figure 4. The transport trolley in question comprises a moveable frame (2) provided with a supporting or carrying surface for, for example, materials to be transported. The frame (2) comprises four wheel supports (4) which are pivotably mounted on the frame (2) in the corner regions of the frame (2), wherein each wheel support (4) comprises a wheel (5) which is connected to the wheel support (4) rotatably about a wheel axis. The transport trolley further comprises a drive wheel (6) which is mounted within the periphery of the frame (2) and is rotatable about a wheel axis, and drive means configured to rotate the drive wheel (6) about its wheel axis. The transport trolley also comprises a drive wheel support (7) which is rotatably connected to the frame (2) and to which the drive wheel (6) is rotatably connected. The frame (2) further comprises means configured to exert a downward force on the drive wheel support (7) so that the drive wheel (6) remains in constant contact with the ground surface over which the transport trolley is displaced. The transport trolley also comprises all the other features, such as the brake system, as described in the case of the hospital bed, with the exception of a lying surface (3), which is height-adjustable with respect to the frame, for a patient.

Claims

1. Transport means (18), provided with a moveable frame (2), which frame (2) comprises four wheel supports (4) which are pivotably mounted on the frame (2) in the corner regions of the frame (2), wherein each wheel support (4) comprises a wheel (5) which is connected to the wheel support (4) rotatably about a wheel axis, wherein the transport means further comprises a drive wheel (6) which is mounted within the periphery of the frame (2) and is rotatable about a wheel axis, wherein the transport means comprises drive means configured to rotate the drive wheel (6) about its wheel axis, wherein the transport means (18) comprises a drive wheel support (7) which is rotatably connected to the frame (2) and to which the drive wheel (6) is rotatably connected, and wherein the frame (2) comprises means configured to exert a downward force on the drive wheel support (7) so that the drive wheel (6) remains in constant contact with the ground surface (19) over which the transport means (18) is displaced, characterized in that each wheel support (4) is arranged rotatably about a respective rotational axis in order to change the displacement direction of the wheels (5), in that the drive wheel support (7) is arranged rotatably about a rotational axis (10) in order to change the displacement direction of the drive wheel (6), in that the transport means comprises a brake system which is adjustable between at least three positions, being a braking position, in which rotation of at least one of said wheels (5, 6) about their respective wheel axis is prevented, a rotation position, in which said wheels (5, 6) are rotatable about their wheel axis and rotational axis, and a direction-fixing position, in which said drive wheel (6) is rotatable about its wheel axis in order to move the transport means and the rotation of said drive wheel support (7) about said rotational axis (10) is prevented, and in that at least one of the wheel supports (4) and the drive wheel support (7) are mechanically coupled to each other.

2. Transport means (18) according to Claim 1, characterized in that the frame (2) further comprises a hingeable arm (8) which is connected to the drive wheel support (7) and rotatably connects the latter to the frame (2).

3. Transport means (18) according to Claim 2, characterized in that said means are sprung means (9), which sprung means (9) comprise a torsion spring, coil spring or gas spring which is configured to exert a downward force on the hingeable arm (8).

4. Transport means (18) according to any of the preceding claims, characterized in that, in said rotation position, the drive wheel support (7) is freely rotatable about its mentioned rotational axis (10) in order to change the displacement direction.

5. Transport means according to any of the preceding claims, characterized in that, in said direction-fixing position, the drive means are activated in order to rotate the drive wheel (6) about its wheel axis to assist the displacement of the hospital bed (1).

6. Transport means (18) according to any of the preceding claims, characterized in that the brake system comprises a brake pedal (11) for adjustment of the various positions.

7. Transport means (18) according to any of the preceding claims, characterized in that said transport means is a hospital bed (1) provided with a lying surface (3), which is height-adjustable with respect to the frame (2), for a patient.

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