Patent Publication Number: US-6219864-B1

Title: Monitoring patient handling equipment

Description:
The present invention relates to patient handling equipment and to a method of monitoring patient handling equipment. 
     Stretcher trolleys are frequently collapsed into a lower position and then raised again. Collapse normally occurs when the trolley is entering an ambulance and the trolley is normally raised when a patient is being manoeuvred on the trolley. Similarly chairs that are used to transport patients are frequently collapsed to a storage position when not in use. 
     The raising and lowering of the trolleys subjects the trolleys to metal fatigue. Whilst trolleys are serviced regularly there is no way of making a visual inspection of the fatigue that the metal has suffered. Accordingly, good practice is to replace the trolleys when they are likely to have undergone a certain number of raising and lowering operations. 
     When trolleys are sold they normally go, in a batch order, to a particular authority. That authority then allocates the stretchers either to inner city front line ambulance services, where the trolleys are subjected to frequent raising and lowering, or to suburban or rural services where frequency of use is far less. Nevertheless, good practice dictates that the trolleys are exchanged when fatigue may have occurred to an extent where replacement is required on the assumption that each trolley is an inner city trolley that has been subject to frequent raising and lowering. Alternatively trolleys are frequently kept in use beyond what is to be an acceptable or safe life span. 
     Similar points apply to the collapsing and erecting of chairs. 
     It is an object of the present invention to attempt to overcome at least some of the above described disadvantages. 
     According to one aspect of the present invention patient handling apparatus includes a support portion movable between a first position and a second position, the arrangement including counting means arranged to provide an indication of the number of the times the support portion has been moved to at least one of the positions. 
     The counting means may be arranged to provide a count when the support portion is moved to at least one of the positions. 
     The counting means may be arranged to provide an indication of the number of times the support portion has been moved to the second position. 
     The counting means may comprise first and second parts that are arranged to move relative to each other when the support portion has moved between the two positions. Relative movement of the first and second parts may be arranged to effect the count. The first part may comprise a magnet and the second part may comprise a counter responsive to the magnet, such as being responsive to movement of the magnet. The first and second parts may be arranged to be spaced from each other when the support portion is being moved between the first and second positions and when the support portion is in the first and second positions and monitoring that indication. 
     The first and second parts may both be arranged to move. One part may move translationally. Alternatively or additionally at least one and preferably both parts may move pivotally. The parts may both be arranged to be mounted in the top region of a stretcher when that stretcher is in both positions. At least one and preferably both parts may be arranged to be located beneath the support portion. 
     The first and second parts may be arranged to come within 10 mm of each other in order to activate the counting means. 
     The counting means may be arranged to record every alternative count. 
     The apparatus may comprise a chair in which the first position is the erect position and the second position is the storage position. 
     The apparatus may comprise a stretcher trolley in which case the first position is an upper position and the second position is a lower position. 
     The trolley arrangement may include a first, upper frame arrangement associated with the support portion and being arranged to move between the upper and lower positions. At least one of the first or second parts of the counting means may be mounted to move when the upper frame arrangement moves between the upper and lower positions. 
     The trolley arrangement may include a second lower frame arrangement that the upper frame arrangement is arranged to move towards and away from when the upper frame arrangement is being moved away from or towards the raised position. 
     The upper frame arrangement may be arranged to be supported directly on the lower frame arrangement when the support portion is in the lower position. 
     The upper frame arrangement and the lower frame arrangement may be connected together by a linkage arranged to control the movement between the upper and lower frame arrangements. 
     At least part of the counting means may be concealed. At least part of the counting means may be located in part of a frame of the patient handling equipment or mounted on or to a part of a frame of the trolley arrangement. The part of the counting means that is located in part of the frame may be visible through part of the frame. Alternatively or additionally that part may be accessible by removing part of the frame such as a cover on part of the frame. 
     According to a further aspect of the present invention a method of monitoring patient handling apparatus comprises providing an indication of the number of times a support portion of the apparatus is moved between first and second positions. 
     The apparatus may comprise a chair in which case the method may comprise monitoring the erecting and collapsing of the chair. Alternatively the apparatus may comprise a stretcher in which case the method may comprise monitoring movement between an upper and a lower position. The trolley arrangement may include wheels that the trolley arrangement is moved on. 
     The method may comprise periodically monitoring the number of times that the support portion has been moved between the upper and lower positions and causing an event to occur as a result of the number of times that a support portion has been moved to at least one of the positions, that event being, for instance, to provide a service for the apparatus, or to vary the service that is provided, or to recommend replacement of at least part of the apparatus. 
     The method may comprise viewing a counter when the apparatus is being monitored and the method may comprise viewing the counter through a part of the apparatus or the method may comprise moving a part of the apparatus in order to view the counter. 
     The method may comprise monitoring alternate counts. 
     The present invention includes any combination of the herein referred to features or limitations. 
    
    
     The present invention may be carried into practice in various ways but several embodiments will now be described, by way of example, and with reference to the accompanying drawings, in which: 
     FIG. 1 is a perspective view of a first stretcher trolley  10  according to a first embodiment of the present invention with the trolley being in the raised position; 
     FIG. 2 is a side view of the trolley  10  in the lower position; 
     FIG. 3 is a perspective view of a stretcher trolley  110  according to a further embodiment of the present invention, and 
     FIGS. 4 and 5 are side views of the trolley  110  in the raised position with the support being at an angle to the horizontal and horizontal respectively; 
     FIG. 6 is a side view of a further embodiment of a stretcher trolley; 
     FIG. 7 is a plan view of FIG. 6; 
     FIGS. 8,  9 ,  10  and  11  are side views showing the trolley of FIG. 6 in various different configurations, and 
     FIGS. 12 and 13 are photographs showing the orientation of two parts of a counting device when the trolley of FIG. 6 is in the upper and collapsed positions. 
    
    
     As shown in FIG. 1 the trolley  10  includes a support portion  12  defined by a back support portion  12   a , a buttock support portion  12   b  and a leg support portion  12   c . The angles of the back and leg support portions can be varied on the trolley by altering the angles of props that extend to beneath the support portion to the main frame of the trolley. The operation of such supports is well known and will not be described further. A mattress  14  can be located on the support portion  12 , as shown in FIG.  2 . 
     The trolley includes an upper quadrilateral frame  16  and a lower quadrilateral frame  18 . The frames  16  and  18  are connected together by a first leg frame  20  that is pivotally connected to an end section  18   a  of the lower frame and a second leg frame  22 . The leg frame  22  is connected to the side sections  18   b  of the lower frame via blocks  24  connected to the side sections  18   b . The legs  22  are connected to the block  24  via rollers  26  that permit the legs  22  to move relative to the blocks  24  to a limited degree between the ends of the blocks in the direction of extent of the side sections  18   a.    
     The leg frames  20  and  22  are connected together by a horizontal pivot rod  28 . 
     The upper end of the leg frame  22  is pivotally connected, at each side, to a bar  30 . Each end of the bar  30  is connected via a shaft  32  to the side of the upper frame  16 . 
     The leg frame  22  is connected to the upper frame  16  by a sliding connection  34  in a well known manner such that, upon pulling of a handle  36  a lug restraining relative sliding movement is released from a slot  38  and the upper leg is able to slide towards or away from the end portion  16   b  of the upper frame. When the handle  36  is released the spring loaded lug returns into the next slot  38  that it comes into alignment with. This sliding movement of the upper end of the leg frame  20  causes the height of the stretcher to be raised or lowered. In the lowermost position sockets  40  are lowered on to spindles  42  of the upper frame and lower frame respectively, as shown in FIG.  2 . In that position the upper frame rests on the lower frame and the leg frames are substantially parallel to each other. 
     In the raised position shown in FIG. 1 the trolley can be manoeuvred by being rolled along wheels  44  which can rotate about a horizontal axis and also about a vertical axis depending downwardly from each corner of the lower frame. In the raised position the trolley can approach an ambulance such that wheels  46 , which can rotate about a horizontal axis and which are connected to the upper frame towards the front end  16   b  just below that end, rest on the floor of the ambulance. If desired the wheels  46  can be arranged to be at a slightly greater height than the floor of the ambulance. The rear of the trolley can then be lifted to pivot the trolley about the wheels  44  and to bring the wheels  46  into contact with the floor of the ambulance. The lower frame is then brought up to the upper frame and detachably retained in position. The trolley is then pushed into the ambulance. Removal of the trolley from the ambulance and the lifting of the upper frame relative to the lower frame is a reversal of the above described sequence. 
     In the lower position shown in FIG. 2 it is possible to manoeuvre the trolley with the wheels  44  providing the rolling motion required. The wheels  46  are just off the floor. 
     The embodiment described in FIGS. 3 to  5  will now be described. Like parts have been given the same numeral prefaced by the numeral  1 . 
     As shown in FIG. 3, the trolley includes an upper rectangular frame  116  of round cross-section tube and a lower rectangular frame  118  also of round cross-section tube. Two pairs of leg frames  120  and  122  are provided with those frames each being connected to two different end sections  118   a . A pivot rod  128  connects the two frames. Back  112   a , buttock  112   b  and leg  112   c  supports are provided which are connected to the upper frame  116 . The position of the back and leg supports can be pivotally adjusted in a well known manner. 
     A handle  136  at one end of the upper frame  116  can be pulled in the lengthwise direction of the trolley in order to move a locking bar (not shown) from a position in which it engages one pair of opposing slots to a position in which it is free of those slots. That rod is connected to the upper end of the frame  120 . When the rod is clear of the slots the upper end of the frame  120  is free to slide towards or away from the end of the upper frame. This allows the trolley to be raised or lowered. When the handle  136  is released the bar, which is spring mounted, is resiliently biased back into engagement with the next pair of slots that it becomes aligned with. The trolley can be collapsed such that the leg frames  120  and  122  are substantially parallel with each other and with supports  40  on the upper frame resting on supports  142  at each corner of the lower frame. 
     Each corner of the lower frame includes wheels  144  that roll about a horizontal pivot with each wheel in turn being supported by a housing that can pivot about a vertical axis at each corner of the lower frame. The front end of the upper frame also includes a pair of spaced wheels  146  at each side that are located just beneath the extent of the upper frame. The stretcher  110  can be inserted into and removed from an ambulance as described in relation to the stretcher  10  and can also be moved on the wheels  144  when the stretcher is in the collapsed position as described in relation to the stretcher  10 . 
     FIG. 4 shows the position that the stretcher can occupy, with the upper frame being inclined such that the front of the upper frame is higher than the lower end of the upper frame. That is achieved by pulling a lever (not shown) that allows the head and foot of the upper frame to be lowered by causing telescopic portions  148  of the leg frames  120  that extend between the pivot rod  128  and the lower end of the leg frame  120  to be extended. When the handle is released the telescopic portion is locked. When the handle is pulled again the head and foot portion can be pushed down to return the upper frame to the generally horizontal position. 
     The trolley  210  shown in FIGS. 6 to  13  will now be described. 
     A patient is arranged to be located on a mattress supported in the region of an upper quadrilateral frame  212 . The frame has a forward leg frame  214  and a rearward leg frame  216  to the lower end of which wheels  218  and  220  are mounted. The wheels  218  are constrained to rotate in one direction but the wheels  210  are able to pivot about a vertical axis. 
     The leg frame  214  is pivotally connected to a block  222  that is able to slide on a rail  224  in the general direction of the elongate extent of the quadrilateral frame  212 . The leg frame  214  is also, at a point intermediate of its upper and lower extent, pivotally connected to a strut frame  225  which, in turn, is mounted to the quadrilateral frame  212  at a pivot  228 . 
     To load the trolley into an ambulance the trolley is rolled on the wheels  218  in the direction of arrow  230 . A protective cover  232  on the strut  226  hits the back of the ambulance and, after one of a pair of levers  233  has been pulled to release the sliding block  222 , the strut is swung to the left by the abutment with the ambulance about the pivot  228 . At this time the front of the trolley is supported on the ambulance floor by a pair of wheels  236  that depend downwardly from the front of the quadrilateral frame  212 . Whilst the strut  226  is moved to the left, the block  222  slides forwardly on the rail to raise the leg frame  214  upwardly and rearwardly about its pivot on the block until the protective cover  234  on the leg frame  214  abuts the ambulance. Continued movement of the frame into the ambulance causes the leg frame  214  and strut  226  to collapse and extend generally parallel to the quadrilateral frame  212 . 
     When the leg frame  214  is moving to its collapsed position the spaced parallel legs of the frame  214  move to be either side of parallel struts  238  that are pivotally connected to the bottom of the leg frame  216  and the quadrilateral frame  212  by a pivot  240 . 
     The rear leg frame  216  is slidably mounted on the rail by means of a block and the leg frame  216  is pivotally mounted on that block. 
     When the rear of the ambulance is abutted by a protective cover  242  in the struts  238 , and when a lever  244  is pulled to release a lock retaining the block in which the leg frame is mounted, the struts  238  move upwardly and rearwardly about the pivot  240  and the leg frame  216  also moves upwardly and rearwardly with the upper part of the leg frame sliding forwardly via the block on the rail. A strut  246  is pivotally connected to the leg frame  216  at a location between the ends thereof and is pivotally mounted on the quadrilateral frame. Eventually the leg frame is substantially coextensive with the quadrilateral frame  212  as wheels  248  on the struts  238  support and guide the rear of the trolley on the floor of the ambulance. 
     FIGS. 8 and 9 show how the blocks on the rail can be moved to and retained in different positions on the rail in order to achieve different operational positions for the trolley. 
     In FIG. 9 both leg frames  214  and  216  are in the fully extended position. 
     In FIG. 11 the legs have been pivoted slightly such that the quadrilateral frame remains horizontal but wheels  250  that can pivot about an axis perpendicular to their rolling axis engage with the ground. The wheels  250  are mounted at the bottom of the forward leg frame adjacent to the wheels  218 . 
     In FIG. 9 the leg frame has been further collapsed such that the wheels  250  are just clear of the ground and, in FIG. 10, the collapse is further on and the wheels  250  are well clear of the ground. 
     Removal from an ambulance is a reversal of the insertion procedure except that the leg frames return under gravity when the relevant parts clear the rear of the vehicle. 
     Referring now to FIGS. 12 and 13, a magnet  252  is secured to a clamp  254  which is bolted on to a cross bar  256  that connects the upper end of the front leg frame  214 . A counter  258  is bolted on to a cross bar  260  that connects the spaced struts  226 . 
     In the position shown in FIG. 12, with the trolley in the upright position, the magnet and counter are spaced from each other. The counter  258  points downwardly and rearwardly and the magnet  252  points upwardly and forwardly. 
     When the frames of the trolley are moved towards each other, the cross bar  256  moves forwardly on the rail and rotates in a clockwise direction and the cross bar  260  rotates in an anticlockwise direction. Consequently the magnet moves forwardly and rotates with the bar  256  and the counter rotates with the bar  260  to cause the magnet to sweep past the counter thereby causing a count to be recorded. When the frames are raised the magnet sweeps past the counter and another count is recorded. If desired, the counter could be arranged to record every other count in order that the number recorded corresponds to the number of turns the stretcher is raised and lowered rather than recording each raising and lowering. 
     In a further embodiment, the magnet and counter could be mounted on different parts of a collapsible chair such that a count is recorded to record each collapsing of the chair. The chair may include a frame with the magnet and counter mounted on different parts of the frame. The magnet and counter may be as described or may move as described in relation to any of the stretcher embodiments. 
     In the first two embodiments, in order to record each time the upper frame is moved towards the lower frame a magnet  252  (or  252 A in FIG. 1) is mounted on the lower frame and a reed switch  258  is mounted on the upper frame. Alternatively these parts could be mounted the other way round. The magnet does not come into contact with the reed switch but, in the lower position, the magnet would be within 10 mm of the reed switch. Each time the magnet comes within that proximity a counter is tripped and the counter moves on one. Accordingly, the counter will record the number of times that the frame has been raised and lowered or, alternatively or additionally the number of times that the trolley has been loaded or unloaded into an ambulance. 
     Either or both of the magnet and the reed switch in all embodiments can be concealed, it can be made weather-proof or can be made tamper-proof or both. In this way the counter is able to continue functioning and is not liable to be subjected to knocks that can push it out of line or detach it from the frame. Furthermore, the adverse whether conditions that the stretcher can be used in will not affect the operation of the counter and third parties are not able to access the counter. 
     In a further embodiment the counter may be located within a block which is mounted on either the lower or the upper frame in order to prevent tampering with the counter. 
     In a further embodiment the counter can be concealed in a tube of the frame. When the trolley is being serviced the tubes can be slid along in order to give access to the counter, the counter can be read and inspected and possibly have a battery replaced before the tube is moved back to conceal the counter again. If desired the tube can be secured in position with secure bolts. 
     A service engineer reading the counter can determine either that the trolley is ready for a service because it has completed, for the sake of argument, two hundred cycles of raising and lowering. Alternatively, a service engineer can determine that the stretcher is due for replacement if, for the sake of argument, the stretcher has been raised and lowered a thousand times. 
     Each trolley is assigned its own serial number and each counter may be given a corresponding serial number either directly on the counter or on the magnet or on a housing for the counter. In that way it will not be possible for counters to be switched from one trolley to another without a service engineer being aware of that switch. 
     The reader&#39;s attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference. 
     All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed,may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. 
     Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features. 
     The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.