Patent Publication Number: US-4545085-A

Title: Wheeled structure for supporting a patient in a sitting position

Description:
The present invention relates to a wheeled structure of the type disclosed in the preamble to the appended claim 1. Such structures are known e.g. from U.S. patent specifications Nos. 3,623,169, 3,694,829, 3,940,808 and 4,157,593. 
     With the structures in question, certain difficulties have sometimes arisen due to the lateral distance between the wheels normally being fixed. On one hand it may be desirable to have the wheels widely spaced apart laterally to maintain the stability of the structure when rolling it up towards a wheelchair or the like, and on the other hand a small width is preferred for enabling the structure to be rolled through relatively narrow passages, for example when transporting the patient into a toilet room. If this width is fixed, it must be a compromise. The U.S. Pat. No. 3,694,829 however discloses a device in which the side members together with the wheels are laterally adjustable for selectively increasing or reducing the width between the side members. In this way the desired functions have been accomplished. This known device is however relatively complicated and expensive, and is suitable only for a specific type of upper portion. The object of the present invention is to achieve a substantially simplified arrangement while obtaining the same result as with the known device, enabling simultaneously various types of upper structure portions to be mounted on the substructure according to the invention. 
     This is accomplished with a structure according to the invention which has the characterizing features set forth in the appended claims. By providing the structure with a base portion in the form of two short interconnected side members supporting the upper portion of the structure, and a pair of long side members connected to the short members by means of pivotable link arms and having link wheels at their ends, the width between the wheel-carrying long side members may be readily reset from a desired minimum width to a desired maximum width, or at any other width chosen therebetween. 
    
    
     A suitable embodiment of the inventive structure is illustrated in the accompanying drawings. 
     FIGS. 1 and 2 show schematically a conventional prior art structure in different working positions. 
     FIG. 3 is a side view of a separate substructure according to the invention. 
     FIG. 4 shows this substructure seen from above, and 
     FIG. 5 is a schematic perspective view of the substructure provided with an embodiment of the upper portion. 
    
    
     The known structure according to FIGS. 1 and 2 has a base portion 10 with two fixed side members 11,12 provided with wheels 13,14. The upper portion is designated by the numeral 15. 
     The base portion 17 according to FIGS. 3 and 4 of the structure according to the invention is provided with two short side members 18,19 secured to each other by means of a cross piece 20. In the side members and the cross piece there are disposed bolt holes 21 for through-going mounting bolts enabling the attachment of various types of upper portions, e.g. an upper portion 22 of the embodiment schematically indicated in FIG. 5, designed in principle as the known embodiment illustrated in FIGS. 1 and 2 and described in the U.S. Pat. No. 4,157,593. 
     At the ends of the short side members there are vertical bearing bolts 22,23,24,25 for pivotally journalling a pair of rear link arms 26,27 and a pair of forward link arms 28,29. The outer ends of the link arms are pivotally connected to a pair of long side members 30,31 by means of vertical bearing bolts 32, 33,34,35. 
     The long side members 30,31 are provided at their ends with link wheels 36. As indicated in FIG. 4, the main portion of the long members 30,31 is disposed on one side of the cross piece 20, that is on the side where the patient will be seated when the patient is supported by the upper portion 22 according to FIG. 5. 
     FIG. 4 shows the long side members 30,31 in their innermost position affording the shortest distance between the long side members. In this figure also the long side members are indicated by dash-dotted lines in a folded-out position, which can be further extended by continued folding-out of the link arms as required, for example when the structure is to be used for moving a patient from a relatively wide chair such as a wheelchair. 
     The rear link arms 26,27 are shorter than the forward link arms 28,29 and therefore, when swinging out the link arms, the long side members will diverge resulting in an increased width between their free portions, that is in the area underneath the patient sitting in the upper portion of the structure. In this way the stability is improved thus counteracting lateral tipping. Furthermore, the structure is more easily rolled up towards a wheelchair for example, due to the facilitated directional setting of the long side members on either side of the wheelchair. 
     The bearing sleeves of the link arms 26,27 are provided with crankshafts 37,38 interconnected by a guide link 39. One sleeve is upwardly extended by means of a sleeve 40 to a crank mechanism 41 having a worm gear (not shown) for turning the sleeve 40 in one or the other direction, which causes the link arms 26,27 to swing outwards or inwards while laterally displacing the long side members for altering the width between them. 
     The inventive arrangement for varying the width between the wheels is thus designed in a simple as well as readily resettable manner.