Transport system including a drive unit

Abstract

 The present invention concerns a transport system including at least one drive unit and at least one, preferably a plurality of transporting units, and a drive unit with motor for use in connection with transporting units with one ore more freely movable wheels, where the drive unit has at least one drive wheel. The drive unit and the transport unit are provided with a corresponding coupling system, and where the at least one drive wheel of the drive unit is disposed at one end of the transport unit during coupling, and where the coupling system includes one or more lifting mechanisms. By using lifting means for lifting one or more of the wheels of the transport unit from the base and to a height above the base, there is achieved the advantage that manual precautions regarding the wheels not being locked in a straight running position is not to be performed. The wheels are, so to say, made superfluous, as the wheels of the drive unit replace them during transport.

Description

Field of the Invention

[0001] The present invention concerns a transport system including a drive unit with motor for use in connnection with transporting units with one or more freely movable wheels, where these units are coupled to the drive unit via a coupling system, and where the drive unit has at least one drive wheel. Furthermore, the invention concerns such a drive unit.

Description of Prior Art

[0002] It is commonly known in hospitals and other places, motorised auxiliary devices are used for transporting hospital beds as well as for moving linen trolleys and other transport vehicles. These known aids are a great relief to the staff having the task of providing transport for the beds and trolleys in question. Common to the beds and trolleys used in such places is that they normally are provided with freely movable wheels, also called swivelling wheels. When a trolley or bed is to be manoeuvred either in place or in a narrow area, these swivelling wheels are clearly an advantage.
However, when transporting along long passages, it is difficult to control a bed or a linen trolley. In order to keep the direction with such a trolley, it may be adapted so that the wheels at one end may be locked such that they no longer can turn about a vertical axis. In this way is also achieved a much more directionally stable driving.
However, it still requires some muscle power to control the bed or the trolley which is also to be pushed or pulled manually.

[0003] There exist various towing apparatuses with motor which may be used on hospital beds, and with such apparatuses a bed may be moved without large muscular effort and other drawbacks associated with such transports. Furthermore, there are systems that may be built into beds as well as in transport trolleys. However, common to the prior art systems is that they are either incorporated in the individual bed or trolley, or that the system is only suited for a certain type of bed or trolley.

[0004] For example, from US 2002/0084116 A1 is known a motor unit which via a coupling system is coupled to a bed or the like. This motor unit is provided with the drive wheels situated in the same area in which the coupling is taking place and it is thus capable of drawing the bed in a directionally stable way. However, when manoeuvring accurately in narrow passages or rooms, the movement is to take place with large turns as control is effected about the coupling at one end of the bed, and thereby the action of swivelling wheels at each corner of the bed cannot be utilised.

[0005] Another solution is known from US 3,876,024. This is a technically advanced solution with a motor part which is pushed in under a bed or the like, and where the bed is coupled to the drive unit at one end of the bed. The motor part has drive wheel located under and about the middle of the bed, which thus is provided centre of rotation about a vertical axis where the drive wheel is located. In order to achieve a certain coupling action, it is necessary with a coupling system that fixes the drive unit to the gable end of the bed. This is done manually by adapting adjustable coupling means. These are also released manually in the same way. Moreover, this drive unit is only adjustable in connection with beds or other transport unit which is only provided with swivelling wheels. These swivelling wheels are also to be released manually from a possible locked position before moving the drive unit.

[0006] It is the object of the invention to indicate a transport system and a drive unit where the same drive unit can be applied for transporting several types of units that are to be moved over shorter or longer distances, and where by using the transport system and the drive unit there is achieved the same manoeuvrability as by freely swivelling wheels..

Description of the Invention

[0007] The invention concerns, as mentioned in the introduction, a transport system including at least one drive unit and at least one, preferably a plurality, of transport units, where drive unit and transport units are provided with a corresponding coupling system, where the at least one drive wheel of the drive unit is disposed immediately at one end of the transport unit during coupling, and where the coupling system includes one or more lifting mechanisms.

[0008] By such a transport system is achieved the great advantage that the drive wheels are acting coupled together with the transport unit, whereby far the most advantages of the freely movable wheels of the transport unit are maintained, and thereby also an optimal ability of manoeuvring the transport unit into position. By using lifting means for lifting one or more of the wheels of the transport unit from the base and to a height above the base, there is furthermore achieved the advantage that manual precautions against the wheels not being locked in a straight running position are not to be performed. These wheels are, so to say, made superfluous, as the wheels of the drive unit replace them during transport.

[0009] By a drive unit according to the invention it is thus possible to tow transport units made with e.g. two straight-running wheels and with two swivelling wheels in an easy and unencumbered way, as the drive unit is coupled to the end of the transport unit having two straight-running wheels. By lifting these off the ground, great mobility of the coupled transport system is achieved.

[0010] A particularly preferred variant of the invention concerns a transport system which is constituted by a drive unit, and where the transport unit is a hospital bed, a linen trolley, a food trolley, a mail cart or another kind of rolling vehicle. Every day there are many movements and transports of beds and trolleys within the health care and eldercare systems. By a transport system according to the invention, many of these movements and transports may be performed without any appreciable load on the staff performing these tasks.

[0011] In a particularly preferred embodiment, the mentioned lifting mechanism or mechanisms are arranged on the drive unit, obviously meaning a cost saving, as all transport units do not have to be equipped with such equipment.

[0012] These lifting mechanisms may be adapted as wheel fixing means which advantageously can be made as brackets fixed to a transverse bar on the drive unit which extends in the width of the transport unit and at least having a length corresponding to the wheel spacing on the transport unit. The wheel fixing means may each also be constituted by two arms which at one end are secured to the transverse bar and which at the other end is provided with at least one hole for receiving a through-going mandrel by which the two are connected. By making several holes in the arms, adjusting options are obtained such that adaptation to different wheel sizes may readily be performed. Adjustment may also advantageously occur where bracket and arms, respectively, are fitted to the transverse bar.

[0013] By arranging the wheel fixing means on the transverse bar, which is typically arranged at a height above the base corresponding to half a wheel height or more such that they extend towards the base and forwards against the wheels, there is achieved the possibility of receiving the wheel in the fixing means as these may be lifted or pivoted, thereby retaining the wheel and lifting it off the base. In particular the technical feature that the wheel, irrespectively whether it is a straight-running wheel or a swivelling wheel, is fixed and lifted off the base, provides the possibility of moving a transport unit in an easy and neat way without using substantial physical strength with the risk of consequent injuries. Therefore, this is a simple and smart solution where particularly the handling of heavy and/or long transport objects is made much easier.

[0014] A drive unit may advantageously be provided with the said transverse bar upon which is arranged wheel fixing means for two wheels, but it may also be with individual wheel fixing means provided at positions corresponding the distance between the wheels on a transport unit. These wheel fixing means may be provided such that a pivoting operation of the fixing means or lifting of the latter is performed, whereby the wheels are lifted. A pivoting action may be effected by using an electric actuator which via a mechanical structure is connected to the wheel fixing means, but it may also be effected by manual operation of e.g. a pedal whereby the same effect is achieved. Other methods may also be applied, and e.g. linear guides with spindles, mechanical parallelogram solutions or similar known displacing mechanisms may be used in combination with known actuators of different type.

[0015] Above is discussed a solution comprising brackets that are brought in contact with the wheels on a transport unit. The coupling may, however, also be effected in other ways. For example, a solution with hooks on the drive unit or on the transport unit may interact with a corresponding coupling member. At least one of these coupling members may advantageously be resilient such that it is the spring force which determines how great force or how great lift to be performed by the coupling in question.

[0016] A drive unit which is particularly applicable for long transport units may advantageously be arranged with one or more front wheels which are passed in under the transport unit and preferably disposed centrally under the transport unit and with one or two other wheels which by coupling together substitute the two wheels of the transport unit. Hereby is achieved a tremendous manoeuvrability as the coupled vehicle consisting of a transport unit and a drive unit now has a point of rotation under and about the centre, which in principle provides maximum freedom simultaneously with a directionally stable rolling. In this case, the drive unit may be with drive wheels under the transport unit as mentioned in the introduction, but may also be with drive wheels in immediate vicinity of the coupling point. In this case, the drive wheels are also the guiding wheels as in fact they substitute the wheels that are fixed and lifted off the base. Finally, there may be drive wheels both under the middle of the transport unit and as the guiding wheels at the end of the transport unit.

[0017] The coupling together of such a drive unit and a transport unit may advantageously include a lifting device provided on the part of the drive unit which is passed in under the transport unit. In principle, this lifting device acts as a kind of jack, which in this way transmits part of the weight of the transport vehicle to the wheels about which the transport system turns. By such a solution is achieved a good and secure transport of particularly heavy transport units.

[0018] Another variant of a towing system according to the invention is a drive unit which is particularly suited and intended for transport units which are shorter than the traditional hospital beds. For example, food trolleys and linen trolleys may advantageously be transported by this variant. The great difference between this variant and the previously mentioned is that there is not one or more wheels under the middle of the transport unit, and that the coupling means furthermore include a second coupling member which is fixed to the end of the transport unit simultaneously with the wheel fixing means coupling two wheels to the drive unit. By such a solution, which in principle is a sack truck being coupled to the transport unit at one end thereof, thereby substituting its own wheels for the two wheels of the transport unit, there is achieved possibility of a good and secure transport where it is the wheels of the drive unit that exert the pulling or pushing force. The point of rotation of such a vehicle is thus at the drive unit.

[0019] A drive unit may e.g. be a kind of sack truck provided with a lifting mechanism with one or more hooks arranged on a mechanical parallelogram solution, whereby a secure and stable coupling with a transport vehicle can be achieved.

[0020] The drive unit is preferably provided with a handlebar on which various control buttons and levers may be arranged. For example, advantageously there may be arranged a switch for lowering and elevating the wheel fixing means, which then may occur without the user having to bend down to the base for performing an action.

[0021] A typical coupling with a transport object with four swivelling wheels, e.g. under a hospital bed, takes place in that the drive unit is placed at a position immediately under the bed and in front of the wheel to be fixed. If the fixing means are constituted by brackets, it may be advantageous to move so close that the brackets touch the wheels. Then the fixing means are lowered until they touch the base or are very close to the base. Then the bed is drawn a short distance towards the drive unit. This has partly the purpose of ensuring that loose swivel wheels are straightened and partly the purpose of placing the wheels of the transport unit in the fixing means. Typically, the user will know when the transport unit is in place since a slight resistance is felt when the wheels of the transport unit are pulled over the front edge of the wheel fixing means. Then the lifting means are activated, e.g. electro-mechanically or manually-mechanically, and the transport unit is now ready for being towed. Uncoupling occurs in the opposite order.

[0022] The second variant of a drive unit, in the case where there is not one or more front wheels under the transport unit, is coupled in the same way with regard to the wheels but is, as mentioned, provided with a further coupling member which is necessary as there are only two wheels only on the drive unit. Such an additional coupling may typically be a simple mechanical coupling which in a simple way fixes the drive unit to the transport unit.

[0023] However, it must be appreciated that a drive unit with wheel fixing and elevating means may be adapted in other ways than the one described here, as the particular and surprising feature of this invention is a simple and rapid coupling between a drive unit and a transport unit whereby great manoeuvrability of the transport unit is achieved. Whether the wheels are fixed and/or lifted in one or the other way, and whether the transport unit is lifted of the base by the wheels or at other positions is not so crucial; however, it is object of the invention that a coupling is effected and that the transport unit is lifted off the base at one end.

[0024] In yet a preferred variant of a drive unit according to the invention, this has at least one set of drive wheels at the end of the drive unit which is placed at one end of the transport unit, where the wheel set is provided with integrated differential. The differential gear may be of an electric type or a mechanical type. However, it has appeared that the use of an electric differential may be advantageous as such a differential does not take up much space and that the drive unit thus can be made with less total height and therefore be adapted to more different types of transport units.
The differential gear ensures that there is always an optimal power distribution between the drive wheels, whereby control becomes easier, as the power distribution between the wheels of the wheel set is regulated when turning.

[0025] The driving wheels may advantageously be driven by an electric motor which is supplied with energy from an accumulator provided on the drive unit, alternatively on the transport vehicle where energy may be transmitted via the coupling means. In a preferred variant of the invention, two accumulators are arranged on the drive unit close to the drive wheels. The self-weight of the accumulators is hereby utilised for pressing the drive wheels against the base, whereby better grip between wheels and base is obtained.

[0026] One accumulator may advantageously be an spare accumulator which is either fully charged or which is to be charged. In that way is achieved an accumulator system with a kind of power reserve which simultaneously has an effect due to the self-weight. At the accumulators or at another point on the drive unit, a socket may advantageously be arranged and to which a charger is connected for charging the accumulators. This connection may be effected manually or automatically by placing the drive unit in a charging station.

[0027] As mentioned previously, a drive unit according to the invention may be adapted to move units that are different in structure, where this device includes a coupling system which is particularly adapted to be coupled together with differently structured units. By this solution, the drive unit may be coupled together with many different transport units. In principle, the only requirement is that the units to be transported are provided with corresponding coupling means. It is thus possible to suffice with having one single type of drive units in e.g. a hospital, as this one type can be used for all the transports taking place at the hospital, right from moving beds with patients, food trolleys, and so on.

[0028] The coupling between drive unit and transport unit can be arranged in many different ways and can be designed according to the wish of the customer. The drive unit may e.g. be adapted with a coupling system which may be operated from the control handle, where the coupling, besides a lifting mechanism, e.g. may include an electromagnetic coupling, a snap-action coupling, a hook coupling, a ball coupling, a drawbolt/draweye coupling, or similar. All these types of couplings can also be made such that they are operated directly at the coupling point. Other types of coupling system than those mentioned here may also be used and the coupling system can be designed such that it fits many differently designed counterparts as well. For example, a drive unit can be provided with a multi-coupling that fits a plurality of different couplings on various transport units.

[0029] A variant of a drive unit is adapted such that the operator may freely choose if he/she will walk at the end of the towage unit or drive with it standing on a trailer arranged for the purpose. Such a trailer may advantageously be provided with straight-running wheels or with swivelling wheels or another suitable type of wheel and may be adapted such that it can be folded up, thus not taking up much space. This may be advantageous by transport in e.g. elevators where the transport unit and the drive unit may just fit by the length. The coupling and thereby the pivotal point between transport unit and trailer may advantageously be disposed close to the vertical axis of the control handle or, in other words, immediately at the end of the transport unit, whereby easy control is obtained.

[0030] A drive unit according to the invention may be designed with coupling members that are adjustable, either steplessly or in predetermined steps, whereby the possibility of rapid adjustment to several types of transport units is possible.

[0031] It is obvious that after having realised the main features of the invention, the skilled in the art will be able to design variants that are not outrightly described in this publication. This kind of variants are, however, considered as comprised by the present invention, as they are based on the same fundamental idea as the disclosed variants.

Short Description of the Drawing

[0032] The invention is described in more detail with reference to the drawing, wherein:

Fig. 1

shows a drive unit with wheel lifters.

Fig. 2

shows wheel lifters prior to fixing the wheels.

Fig. 3

shows wheel lifters in lowered position.

Fig. 4

shows the wheels in the wheel lifters.

Fig. 5

shows a wheel which is fixed and lifted up.

Fig. 6

shows a drive unit without a front wheel.

Fig. 7

shows details of Fig. 6.

Detailed Description of the Invention

[0033] In Fig. 1 appears a variant of a drive unit 2 where this is provided with coupling means that includes combined wheel fixing and lifting means 18, in the following called wheel lifters 18. The drive unit is designed with a forwardly directed part 4 and a transverse part 5. On the forwardly directed part 4 is shown an accumulator pack 11 and an empty space 19 for yet another. At the front on the forwardly directed part 4, a set of wheels 9 is arranged, here shown as wheels that do not drive. The drive wheels 20, however, are arranged under the transverse part 5 where also an electric motor and control electronics are placed under a guard 21. Immediately over the drive wheels 20, of which only one is visible, there is arranged a control handle 6 connected with the drive wheels which can turn. Behind the transverse part 5 is seen a trailer 13 with swivelling wheels 22. The trailer 13 may be folded up or dismounted according to need.

[0034] Immediately in front of the transverse part appears a set of wheel lifters 18 consisting of a transverse bar 23 with a length approximately corresponding to the width of a not shown hospital bed. This transverse bar 23 is rotatable about its longitudinal axis and fastened to the transverse part 5. Turning the bar 23 is effected by electric actuators 24, which are shown here fixed at one end to the forwardly directed part 4 and at the other end to arms 25 mounted on the transverse bar 23. The transverse bare 23 is shown here with adjusting options in the width, as it is designed telescoping and with adjusting screws 26. At the extreme end of the transverse bar 23, the wheel fixing brackets 27 are seen and which also are adjustable in depth by adjusting screws 28. Furthermore, a stop plate 29 is seen which the not shown wheel is to abut on during the fixing operation.

[0035] In Fig. 2 appears the drive unit 2 moved into position under a hospital bed 3, 30, where the wheel fixing bracket 27 is immediately in front of a swivel wheel 31 of the hospital bed 30.

[0036] In Fig. 3, the wheel fixing bracket is shown in lowered position, and it appears that the front part 32 of the wheel fixing bracket 27 is designed flat in order that the wheel 31 may more easily be pulled over this front edge 32. The wheel fixing bracket is lowered in that the actuators 24 are activated and perform a turning movement of the transverse bar 23. During transport of the drive unit 2, as a rule the transverse bar and thereby the wheel fixing brackets 27 are always lifted off the base.

[0037] In Fig. 4, the wheels 31 are seen in position in the wheel lifters 18 of the drive unit, where the wheel 31 on the transport unit 3, 30 is in contact with the stop plate 29, and the front part 32 on the wheel fixing bracket 27 is located at the other side of the contact area of the wheel 31 with the base.

[0038] In Fig. 5, the wheel lifter is seen in operation, where the wheel 31 is fixed in the wheel fixing bracket 27, clamped between the stop plate 29 and the front part 32 of the bracket 27, and lifted off the base in that the actuator 24 is activated, thereby having performed a rotating movement of the transverse bar 23. In this position, the transport unit 3, here a hospital bed 30, is ready for transport. The two wheels 31 lifted off the base are now substituted by the wheels 9 and 20 on the drive unit 2, and a more easy transport may take place.

[0039] Particularly for the type of drive unit appearing in Figs. 1 - 5, it is unbelievably easy to perform coupling between drive unit and transport unit. Even though there are many different types of transport unit with different designs, they may readily be coupled together anyway. This is due to the fact that the wheels on these in far the most cases are disposed uniformly in general, or with differences no greater than the wheel fixing brackets can be adapted to be able to absorb these tolerances. If there should be units that do not fit together, adjustment of the width of the transverse bar 23 and possibly the depth setting of the wheel fixing brackets may be performed reasonably easily and rapidly.

[0040] In Fig. 6 is seen a further variant of a drive unit 2 where only two drive wheels 20 are provided. This drive unit 2 is shown immediately in front of a transport unit 3 which is here constituted by a grating cart with two straight-running wheels 33 and with two not shown swivelling wheels. In front of the transverse part 5 is arranged coupling means including combined wheel fixing and lifting means 18. This is a solution which in principle corresponds to the solution shown in Figs. 1 - 5. In this variant of a drive unit 2, there is the additional difference that it is provided with a further coupling member 34 which is shown in a simple variant with a hook member fixed to the transport unit 3 at its gable side. With this further coupling member 34 in interactive action with the combined wheel fixing and lifting means 18, a certain transmission of weight to the drive wheels 20 and a secure fixing to the wheels 34 as well as to the transport unit 3 are achieved.

[0041] In Fig. 7, details of a drive unit 2 as shown in Fig. 6 are shown. Among others is seen that between the drive wheels 20 there is a guard 21 under which an electric motor and the necessary control electronics are disposed. Above this guard 21 is arranged an accumulator pack 11 which may easily be replaced when required. In front of the transverse part 5, the combined wheel fixing and lifting means 18 are arranged. In this variant also, rotating the transverse bar 23 is effected by actuators 24 which are here fastened to a fixed point under the accumulator pack 11 and to arms 25 on the transverse bar 23. By activating the mounted actuator or actuators, the wheel fixing brackets 27 may be lowered and elevated according to need. Operation of the actuators may advantageously be effected by an electric switch on the control handle 6, but other methods may of course be used for rotating the transverse bar 23.

Claims

1. A transport system including a drive unit with motor for use in connnection with transporting units with one or more freely movable wheels, where these transport units are coupled to the drive unit via a coupling system, and where the drive unit has at least one drive wheel, characterised in that the transport system includes at least one drive unit and at least one, preferably a plurality of transport units, that drive unit and transport units are provided with a corresponding coupling system, that the at least one drive wheel of the drive unit is disposed immediately at one end of the transport unit during coupling, and that the coupling system includes one or more lifting mechanisms.

2. Transport system according to claim 1, characterised in that the transport system is constituted by a drive unit, and that the transport unit is a hospital bed, a linen trolley, a food trolley, a mail cart or another kind of transport vehicle.

3. Transport system according to claim 1 and 2, characterised in that the lifting mechanism is arranged on the drive unit.

4. A drive unit with motor for use in connnection with transporting units with one or more freely movable wheels, where these transport units are coupled to the drive unit via a coupling system, and where the drive unit has at least one drive wheel, characterised in that the at least one drive wheel of the drive unit is disposed immediately at one end of the transport unit during coupling, and that the drive unit is provided with a coupling system including one or more lifting mechanisms.

5. Drive unit according to claim 4, characterised in that the drive unit extends from one end and in under the transport unit, that there is at least one freely movable wheel on the part of drive unit located under the transport unit, and that the drive unit extends at least a length along one end of the transport unit.

6. Drive unit according to any of claims 4 and 5, characterised in that the drive unit has at least one set of drive wheels with integrated differential gear at the end of the drive unit which is placed at one end of the transport unit.

7. Drive unit according to any of claims 4-6, characterised in that the drive unit is adapted for transport units that are different in structure, that this device includes a coupling system adapted to interacting with and partly lifting the transport unit.

8. Drive unit according to any of claims 4 -7, characterised in that the drive unit is adapted with a coupling system which may be operated from a control handle, where the coupling e.g. includes wheel fixing and lifting means, a hook coupling, or similar.

9. Drive unit according to any of claims 4 -8, characterised in that the drive unit is arranged with a trailer for transporting an operator of the drive unit.

Drawing