Hoisting apparatus
The present invention relates to a hoisting apparatus for hoisting or lifting an object, such as a bath tub, which is operatively connected to at least one fixedly mounted power actuator, for example a pressure-cylinder and piston device, through a coupling or carrier unit cooperating with at least one fixedly mounted guide member. 
     In hoisting apparatus of the type mentioned above a problem is frequently encountered which resides in that under high-load conditions movable parts tend to cant relative to adjacent fixed parts, accompanied by the risk of wedging of the movable parts. Particularly where the hoisting apparatus is intended to carry out extensive lifting movements, the wedging problem may become serious so that the risk of substantial deformations or breakages of load-carrying parts cannot be excluded. 
     Efforts made with a view to solve the guiding function in hoisting apparatus have resulted in complex and, first and foremost, heavy, unwieldy and expensive constructions. 
     It is an object of the present invention to eliminate these drawbacks and to provide a hoisting apparatus which is extremely simple, stable and well-functioning, while eliminating at the same time any tendencies of wedging. This result, according to the invention, is substantially accomplished by the fact that the hoisting apparatus comprises at least one guiding sleeve forming part of the coupling unit and being positively guided to move along the guide member by embracing the latter, the guiding sleeve being arranged on the one hand to control at least one device connecting the connecting unit with the power actuator, and on the other hand to control at least one connecting member forming part of the connecting unit. 
    
    
     The invention will be described in greater detail hereinafter with reference to the accompanying drawings, in which: 
     FIG. 1 is a front view of the hoisting apparatus according to the invention; 
     FIG. 2 is a view in cross section taken along line II -- II in FIG. 1; 
     FIG. 3 is a side elevational view of the hoisting apparatus; 
     FIG. 4 is a plan view of the hoisting apparatus; 
     FIG. 5 is an enlarged side view of a portion of the apparatus; 
     FIG. 6 is a plan view of the portion illustrated in FIG. 5; 
     FIG. 7 is a side view of the hoisting apparatus; 
     FIG. 8 is a rear end view of the hoisting apparatus; 
     FIG. 9 is a side view of the hoisting apparatus and illustrates the mounting arrangement according to the invention; and 
     FIG. 10 is a plan view of the hoisting apparatus. 
    
    
     The hoisting apparatus illustrated in the drawings is intended to be used for hoisting or lifting an object or load disposed alongside the apparatus. The principal components of the hoisting apparatus are a frame 1, at least one power actuator 2 mounted on the frame 1, guide means disposed on the frame 1 and including at least one guide member 3, a coupling unit 4 cooperating with the guide member 3 and carrying the object to be lifted, for instance a bath tub 6, and a connecting device 5 connecting the power actuator unit 1 with the coupling unit 4. 
     The frame 1 illustrated in the drawings is intended to be cast into a floor for stationary installation. The frame 1 in principle, is boxlike in structure and comprises a base plate 1a adapted to be cast into the floor, while an upper portion 1b forming the top of the frame is adapted to lie flush with the floor surface. Projecting upward from the upper frame portion 1b are side flanges 1c serving as reinforcements for the frame and, in addition, as mounting flanges for the guide members 3. As an alternative to a stationary, cast-in-frame, it would be possible, of course to use a frame that is free-standing on the floor (not illustrated) for carrying the hoisting apparatus. 
     As power actuator 2 a device is preferably used which comprises a pressure cylinder 2a and a piston 2b displaceable therein and having a piston rod 2c projecting upwardly from the cylinder 2a. In order to obtain a water-driven (so-called water-hydraulic) power actuator, the chamber 2d for receiving the operating fluid of the cylinder 2a may be connected to the domestic water mains or to a separate pump. As alternatives to water-driven power actuators, electro-mechanical or electro-hydraulical devices may be employed. 
     In order to obtain a simple and stable design of this hoisting apparatus and to avoid any risk of wedging of movable parts, according to the present invention, at least one guide sleeve 4a forming part of the coupling unit 4 is positively controlled to move along the guide member 3 by embracing the same, this guide sleeve 4a being adapted on the one hand to control the connecting device 5 for connecting the coupling unit 4 with the power actuator 2, and on the other hand to control at least one coupling member 4b forming part of the unit 4. One of the coupling members 4b is mounted on the front side of each of the guide sleeves 4a, as is clearly shown in the drawings. 
     To ensure a stable and positive connection between the power actuator 2 and the coupling members 4b of the coupling unit 4, the connecting device 5 and the coupling members 4b are both individually mounted on the guide sleeve 4a, that is to say the guide sleeve 4a interconnects the connecting device 5 with the coupling members 4b. The combination of the connecting device 5 with the coupling unit 4 will be especially stable if, as seen in plan view, the guide sleeve 4a forms a corner piece between a portion 5a of the connecting device 5 and the coupling members 4b. An advantageous symmetry of load transmission will be obtained in particular if the coupling member 4b projects from the front side of its associated guide sleeve 4a in such a way that an imaginary extension of the coupling members 4b would intersect the guide members or column 3. In this connection it would be advantageous to connect the coupling device 5 to the guide sleeve 4a in a manner to cause an imaginary extension of the portion 5a to intersect the guide column 3. As is seen from the drawings, the vertical elements 5a of the device 5 are secured to the inner portions of their associated guide sleeves 4a. 
     In order to provide a ridig and positive guide member 3 and guide sleeve 4a without any necessity of over-dimensioning these parts, the guide member 3 may be designed with a four-sided, preferably rectangular, tubular cross-section, and the guide sleeve may be a four-sided, preferably rectangular part. The guide member 3 preferably includes sheet-metal angular corner plates 3a made, for example, of stainless steel and formed with sliding surfaces, and the guide sleeve 4a cooperates with these corner plates 3a through the intermediary of bearing elements 4e made, for example, of plastic material. The corner plates 3a and bearing elements 4e enable sliding movement of the guide sleeve 4a, prevent binding through any formation of rust and in addition enable a well-guided sliding of the guide sleeve 4a along the guide member 3. 
     In the embodiment shown the hoisting apparatus is particularly well balanced for loads by the power actuator 2 carried between the guide members 3 so that the guide sleeves 4a are rigidly connected with each other by the member 5a of the coupling device 5 disposed between the guide members 3. As seen from the drawings, the member 5a in turn is secured to the lifting part of the power actuator 2, i.e. to the piston rod 2c. 
     As an additional stabilizing factor the guide columns 3 may have their outwardly facing sides welded into the inwardly facing sides of the frame flanges 1c, which would enable the guide members to take up high bending stress in the forward direction. 
     The hoisting apparatus according to the invention is adapted to carry a plurality of coupling members 4b, which is possible due to the expedient that each member 5b forming part of the coupling device 5 and extending vertically inwardly of the guide members 3 forms a carrier for at least two vertically aligned guide sleeves 4a having coupling members 4b. Due to the side-by-side arrangement of the power actuator 2, guide members 3 and coupling device 5, a very rigid &#34;power pack&#34; for lifting substantial loads is obtained. 
     It is possible, within the scope of the appended claims, to vary the number of elements from which the hoisting apparatus is assembled, and also to vary the design of elements forming part thereof. Thus, for example, although at least one guide member or column 3 is required, it would be possible to employ two, three or more guide members. To limit the lifting stroke, the guide column 3 may be provided with a stop abutment 3b at its top end. Furthermore, the number of guide sleeves can be varied too, as well as the number of coupling devices 4b. To conceal or protect the hoisting apparatus it may be placed in a casing 7 carried by the frame, and outside this casing 7 a panel 8 may be disposed which is mounted in the guide sleeves 4a and is intended to carry various articles of equipment, such as any required sanitary equipment. 
     The hoisting apparatus and the object to be lifted present a mounting arrangement which, according to the invention, substantially comprises at least one, preferably two, upper coupling elements 4c for taking up tensile stresses and at least one, preferably two, lower coupling elements 4d for taking up compressive stresses. Furthermore the bath tub 6 comprises at least one fitting 6a cooperating with the upper coupling element 4c and at least one support 6b cooperating with the lower coupling element 4d. The coupling elements 4c, 4d and associated fitting 6a and support 6b on the one hand are entirely disposed between the power unit and the side 6c of the bath tub 6 facing the power unit, and on the other hand, are designed as interconnectible coupling devices which carry the bath tub 6 as a cantilever supported unit adjacent the hoisting apparatus. 
     The advantages of this arrangement reside in the first place in the obtainment of a very simplified and stable construction which, due to its simple design, will substantially reduce the manufacturing cost compared to prior art arrangements of a corresponding type. Furthermore the interior of the bath tub 6 and/or the occupant of the bath tub will become more easily accessible since three of the bath tub sides are completely free from connecting arrangements. This will also involve increased possibilities of utilizing a transfer device for transferring patients into and out of the bath tub 6. In addition, the entire equipment can easily be kept neat and clean, a factor of particular importance when the equipment is to be used in sanitary installations. Since both hoisting gear and bath tub 6 are devoid of lengthy carrier arms projecting therefrom, the mounting and assembly operation is simple, and the units will not be bulky and unwieldy during transportation and internal handling thereof. 
     In order to provide a particularly safe and also simple mounting arrangement, the upper coupling element 4c, at least, may include a coupling plate (not shown) and the fitting 6a may include a coupling plate 6d (the support 6b may include a coupling plate 6e cooperating with the lower coupling element 4d), the coupling plates being interconnected by bolts 7 or the like. 
     In order to obtain a positive attachment of the fittings 6a to the bath tub 6, these fittings are attached on the one hand to the outer surfaces of the bath tub wall, and on the other hand to the underside of a flange 6f projecting from the top-edge of the bath tub wall. 
     To make the bath tub 6 less unwieldy during transportation and also easily attachable to the hoisting apparatus, the fitting 6a and support 6b may be disposed entirely inwardly of a vertical plane extending through the edge 6g of the projecting flange 6f so that the engagement surfaces of the fitting 6a and support 6b will lie substantially in this vertical plane. 
     The region of attachment between fitting/support and bath tub 6 will be very rigid if each fitting 6a and/or support 6b is connected to a reinforcement (not shown) extending along and attached to a portion of the side 6c of the bath tub 6 facing the hoisting apparatus and also along and attached to a portion of another side of the bath tub 6. 
     As will be seen from the arrangement illustrated in the drawings the inventive arrangement includes two upper coupling elements and fittings cooperating therewith, and two lower coupling or supporting elements and supports cooperating therewith. The upper coupling elements and fittings are interconnected by being screwed or hooked together. The lower coupling elements and supports may be interconnected in a similar way, but it is simpler and frequently enough to let the supports rest on the lower coupling elements. 
     In addition to the inventive arrangement here described and its advantages, structural modifications and features not illustrated are possible within the scope of the appended claims. In connection with the arrangement here described, it may be mentioned that the bath tub outlet 8 may be connected to a spirally coiled discharge hose (not shown) whose terminal end is immersed into a drain gutter (not shown). This will ensure a non-splashing discharge of the bath tub 6 even when the tub is disposed at a high level above the floor.