ARRANGEMENT FOR TRANSFER OF A TROLLEY BETWEEN SUSPENDED RAILS AND SUSPENDED RAIL SYSTEM COMPRISING SUCH AN ARRANGEMENT

ARRANGEMENT FOR TRANSFER OF A TROLLEY BETWEEN SUSPENDED RAILS AND SUSPENDED RAIL SYSTEM COMPRISING

SUCH AN ARRANGEMENT

Technical Field of the Invention

The invention relates to the field of suspended rail systems for patient lifts. In particular, the invention relates to a system for allowing safe transfer of a patient lift trolley between two suspended rails.

Technical Background

Patient lifts which ride on suspended rail systems are commonly used as an aid for lifting, lowering and moving persons who need such assistance, for example patients, elderly or disabled persons. The patient lift is usually coupled to a trolley which rides in a rail of the suspended rail system. Such suspended rail systems may comprise primary rails which are non-movable, e.g. attached to the ceiling, and one or more secondary rails which are suspended from the primary rails and movable relative these. There may arise a need to transfer the patient lift from one secondary rail to another, or between a secondary rail and a fixed rail, or between any two rails. This type of transfer may be achieved by positioning the two rails end-to-end and thereafter slide the trolley from one rail to the other. During normal operation however, it is desireable for the rails to have stop means to prevent the patient lift trolley from accidentally leaving the rail. To avoid time-consuming manual removal of the stop means during a transfer situation, there has been proposed mechanisms for automatically releasing the stop means to allow a transfer. One such mechanism, called the "Transition gate", is provided by Prism Medical Ltd. The "Transition gate" comprises rod-shaped stop members which extend into the rails in the vicinity of the ends thereof. The stop members are movable at a right angle relative the length direction of the rails to be able to either block or allow movement of a trolley through the rail. A wheel member is coupled to each stop member at a right angle. The wheels are arranged to interact with guides such that the stop members are lifted. Transfer of the patient lift trolley between two rails is possible only at certain positions where a guide is attached to a primary rail. At this position, the wheel attached to the stop member of a first rail engages with the guide which is attached to the primary rail, and the wheel attached to the stop member of the second rail engages with a guide being attached to the first rail. Thereby both stop members are lifted and transfer is possible. One problem with such a mechanism may be that both secondary rails need to be moved to the predetermined position where a guide is attached to a primary rail in order to make a transfer possible. Another problem is that the trolley may accidentally leave one of the rails, thereby causing an accident, because a stop member may be lifted without having another rail positioned end-to-end, e.g. when a rail is positioned such that its stop member wheel engages with a guide which is attached to a primary rail.

Summary of the Invention

It is an object of the present invention to provide a time-efficient and safe arrangement for allowing transition of a trolley between a first and a second suspended rail, and for preventing the trolley from accidentally leaving the rails, and at the same time providing such an arrangement with a simple and cost-effective construction. A further object of the present invention is to provide a suspended rail system comprising such an arrangement.

These and other objects of the present invention are achieved by means of an arrangement and a suspended rail system having the features defined in the independent claims. Embodiments of the present invention are

characterized in the dependent claims.

According to a first aspect of the invention, there is provided an arrangement for safe transition of a trolley between a first and a second suspended rail when they are in an end-to-end position with each other, and for safe operation of the trolley when the rails are in un-aligned positions relative each other. The arrangement comprises a liftable or movable first stop member, a liftable or movable second stop member, and two pairs of engaging or actuating members.

The liftable first stop member is adapted to block the trolley from accidentally leaving the first rail when the rails are in the un-aligned positions, and to unblock the first rail when the rails are in the end-to-end position. The liftable second stop member is adapted to block the trolley from accidentally leaving the second rail when the rails are in the un-aligned positions, and to unblock the second rail when the rails are in the end-to-end position. One pair of engaging members have a first engaging member adapted to be attached to the first rail and a second engaging member attached to the second stop member. One pair of engaging members have a third engaging member adapted to be attached to the second rail and a fourth engaging member attached to the first stop member. The engaging members of the pairs of engaging members are arranged to engage with each other when the rails are in the end-to-end position to lift the stop members, thereby unblocking the rails in order to allow a transition between the rails.

According to a second aspect of the invention, there is provided a suspended rail system comprising a first suspended rail, a second suspended rail and an arrangement according to the first aspect of the invention.

The invention is based on the insight that safe transition of a trolley between a first and a second suspended rail may be achieved by mutual engagement between pairs of engaging members, where one of the engaging members is attached to one of the rails, and the other is attached to a stop member of the other rail, to allow the stop members to be released or lifted when the rails are at arbitrary absolute positions given that the rails are positioned end-to-end. The invention is furthermore based on the insight that by using such a mutual engagement between pairs of engaging members, the stop members may be released or lifted when, and only when, the rails are positioned end-to-end.

In other words, according to the first aspect of the invention, an arrangement is provided for allowing a transition, transfer or move of a trolley or patient lift trolley between a first and a second suspended rail or track when the rails or tracks are mutually aligned, and for preventing the trolley or patient lift trolley from accidentally leaving the rails or tracks when they are not mutually aligned. Put differently, there is provided an arrangement for enabling a trolley or patient lift trolley to be transferred or moved between a first and a second suspended rail or track when one end of the first suspended rail or track is positioned facing one end of the second suspended rail or track, and for blocking a trolley or patient lift trolley from leaving the rails through the one end of the first suspended rail or track and/or through the one end of the second suspended rail or track when the one end of the first suspended rail or track is not positioned facing the one end of the second suspended rail or track.

The arrangement comprises a liftable or movable first stop member, a liftable or movable second stop member, a first pair of engaging or actuating members and a second pair of engaging or actuating members. The liftable or movable first stop member is adapted to partially block the one end of the first rail or track or extend into the first rail or track when the rails or tracks are unaligned or not mutually aligned or when the one end of the first suspended rail or track is not facing the one end of the second suspended rail or track.

Thereby the trolley or patient lift trolley is blocked or prevented from leaving the first rail or track. The liftable or movable first stop member is furthermore adapted to unblock the first rail or track when the rails are mutually aligned or when the one end of the first suspended rail or track is positioned facing the one end of the second suspended rail or track. In other words, the first stop member is movable between a blocking position and a non-blocking position, depending on if the rails or tracks are positioned end-to-end or not.

The liftable or movable second stop member is adapted to partially block the one end of the second rail or track or extend into the second rail or track when the rails or tracks are un-aligned or not mutually aligned or when the one end of the first suspended rail or track is not facing the one end of the second suspended rail or track. Thereby the trolley or patient lift trolley is blocked or prevented from leaving the second rail or track. The liftable or movable second stop member is furthermore adapted to unblock the second rail or track when the rails are mutually aligned or when the one end of the first suspended rail or track is positioned facing the one end of the second suspended rail or track. In other words, the second stop member is movable between a blocking position and a non-blocking position, depending on if the rails or tracks are positioned end-to-end or not.

The first pair of engaging or actuating members comprises a first engaging or actuating member adapted to be attached or coupled to the first rail or track and a second engaging or actuating member attached or coupled to the second stop member. The second pair of engaging or actuating members comprises a third engaging or actuating member adapted to be attached or coupled to the second rail or track and a fourth engaging or actuating member attached or coupled to the first stop member. The first engaging or actuating member is arranged to co-operate or engage with the second engaging or actuating member when the rails are mutually aligned or when the one end of the first suspended rail or track is positioned facing the one end of the second suspended rail or track, thereby unblocking the second rail or track, thereby enabling the trolley or patient lift trolley to move through the one end of the second rail or track in order to allow a transition, transfer or move between the rails. The second engaging or actuating member is arranged to co-operate or engage with the fourth engaging or actuating member when the rails are mutually aligned or when the one end of the first suspended rail or track is positioned facing the one end of the second suspended rail or track, thereby unblocking the first rail or track, thereby enabling the trolley or patient lift trolley to move through the one end of the second rail or track in order to allow a transition, transfer or move between the rails or tracks.

It is understood that the stop members are lifted when the pairs of engaging members engage with each other, and otherwise remain in non-lifted or blocking positions by gravitational force.

In an embodiment of the invention according to the first and/or second aspects, the first and third engaging member each has a guide, and the second and fourth engaging members each has a protruding portion adapted to run in respective guide. Each guide has at least one rising portion in order to elevate the protruding portion to lift the stop members. In other words, the protruding portions of the second and fourth engaging members are adapted to slide, run or mate with the guides of the first and third engaging members, respectively. Because each guide has at least one rising portion, the protruding portions and the thereto attached stop members are elevated or lifted when the pairs of engaging members engage or interact with each other.

In another embodiment of the invention according to the first and/or second aspects, each guide may furthermore have a falling portion. The falling portion may be symmetric with the rising portion. Thereby, the trolley is elevated and lowered in the same manner independent of the direction of relative movement between the first and second rail, i.e. independent of from which side of the engaging member the protruding portion enters the guide.

In another embodiment of the invention according to the first and/or second aspects, the protruding portions of the second and fourth engaging members may be arranged facing each other. The rising portion of the first engaging member may have a different rise than that of the third engaging member. This is advantageous because collision or interference between the protruding portions of the second and fourth engaging members may be avoided due to their different vertical positions because of the different rise of the rising portions.

In yet another embodiment of the invention according to the first and/or second aspects, the guide of the first engaging member and the guide of the third engaging member may be vertically offset relative each other when the first and third engaging members are attached to the first and second rails, respectively. The vertical offset may be achieved by attaching the identical first and third engaging members in a vertically offset manner to the first and second rails, respectively. Alternatively, the first engaging member may have a guide which is arranged at a vertical position in the first engaging member which is offset compared to the vertical position of the guide of the third engaging member. Having such an offset is advantageous because collision or interference between the protruding portions may be avoided. In yet another embodiment of the invention according to the first and/or second aspects, the second and fourth engaging member each has a guide, and the first and third engaging members each have a protruding portion adapted to run in respective guide. Each guide has at least one falling portion in order to elevate the second and fourth engaging members. In other words, the first and third engaging members, which are adapted to be attached to the first and second rails, respectively, each have a protruding portion which consequently is non-movable relative the rails. The second and fourth engaging members, who are attached to the first and second stop members, respectively, each has a guide with at least one falling portion. When the protruding portions enter the falling portions of the corresponding guides, the second and fourth engaging members are elevated or lifted. Thereby, the thereto attached stop members are also elevated or lifted. In yet another embodiment of the invention according to the first and/or second aspects, the first and the third engaging members may be vertically offset relative each other. Having such an offset is advantageous because collision or interference between the protruding portions may be avoided.

In yet another embodiment of the invention according to the first and/or second aspects, the protruding portion is a wheel portion. Thereby, low friction may be achieved when the protruding portions run in the respective guides. In other embodiments the protruding portion is a pin portion or a stud portion.

In yet another embodiment of the invention according to the first and/or second aspects, the guides may comprise a recess portion at the apex of the guide such that the protruding portions are held in position where the stop members are at their most elevated position.

In yet another embodiment of the invention according to the first and/or second aspects, the guides are grooves or comprise groove portions. The diameters of the wheel portions of the second and fourth engaging members may essentially equal the widths or heights of the grooves or groove portions of the first and third engaging members or the second and fourth engaging members, respectively. Thereby, the stop members are essentially fixed in a vertical direction when the wheel portions run in the grooves or groove portions. The groove or groove portions may be essentially gaussian-shaped. In another embodiment, the groove or groove portions may comprise a rising portion and a falling portion. The rising and/or the falling portion(s) may have a linear, exponential or logarithmic rise or fall. The groove or groove portions may furthermore comprise a plane portion or a convex portion between the rising and the falling portions.

In yet another embodiment of the invention according to the first and/or second aspects, the guides may be cams or cam guides, i.e. guides having rising and falling surfaces on which the protruding portions are adapted to run. The cam or cam guide may be essentially gaussian-shaped. The rising and/or the falling surfaces may have linear, exponential or logarithmic rise or fall. The cam or cam guide may furthermore comprise a plane surface or a convex surface between the rising and the falling portions.

Brief Description of the Drawings

These and other aspects of the present invention will now be described in more detail, with reference to the appended drawings showing currently preferred embodiments of the invention, wherein:

Fig 1 is an illustration of a system in accordance with an embodiment according to the second aspect of the invention where the rails are in un- aligned positions,

Fig 2 is an illustration of the system in fig. 1 , where the rails are in an end-to-end position,

Fig 3 is an illustration of the system in fig. 1 and 2, where the rails are in un-aligned positions,

Fig 4 is an illustration of a system in accordance with an embodiment according to the second aspect of the invention where the rails are in unaligned positions,

Fig 5 is an illustration of the system in fig. 4, where the rails are in an end-to-end position,

Fig 6 is an illustration of the system in fig. 4 and 5, where the rails are in un-aligned positions.

Detailed Description

In the following description, an embodiment of the present invention is described with reference to a suspended rail system having first and second rails and an arrangement for safe transition of a trolley between the rails.

Fig 1 shows a suspended rail system according to an embodiment of the invention. A first rail 1 and a second rail 2 being arranged in parallel and having rectangular cross-sections are shown. In other embodiments, the rails may have a quadratic or partially curved cross-section. The rails 1 , 2 are adapted to allow a trolley to ride therein. The trolley may be of the type having a mounting bracket attached to its bottom portion. The mounting bracket is adapted to have a hook or holder attached thereto such that a portable patient lift may be suspended therefrom. Alternatively, a motor device for elevating or lowering the patient may be coupled to the mounting bracket directly or via a hook or holder. The rails each have a slit in their bottom surfaces extending along the length of the rails such that a trolley having for example a portable patient lift or a motor device coupled thereto may move or ride in the rail. The first rail 1 has an end surface 3, and the second rail 2 has an end surface 4. In fig 1 , the rails are not mutually aligned or in an end-to- end position, i.e. the end surfaces 3, 4 are not facing each other.

On top of the first rail 1 , a first engaging member 5 is attached, and on top of the second rail 2, a third engaging member 6 is attached. The first and second engaging members 5, 6 have T-shaped cross-sections as seen from above, and have plane front surfaces 5a, 6a adapted to face each other when the rails 1 , 2 are arranged in an end-to-end position. The front surfaces 5a, 6a are at right angles with the direction of extension of the rails. The T-shaped cross-section is chosen to ensure stable attachment possibilities to the rails and the shape may be chosen in any appropriate way as realized by the person skilled in the art. The engaging member 5, 6 each have a groove 5b, 6b cut into the front surfaces 5a, 6a. The grooves 5b, 6b have a Gaussian- shaped extension and start and end on either side of respective engaging members 5, 6. The grooves have a rectangular cross-section with a depth which is approximately one-third of the width. The groove 6b has a larger rise than that of the groove 5b.

The first and second engaging members furthermore each have a vertical groove 5c, 6c cut into the front surfaces 5a, 6a. The vertical grooves 5c, 6c are deeper than the Gaussian-shaped grooves 5b, 6b, and extend partially along the height of the first and second engaging members, leaving a lower portion of the front surfaces 5a, 6a un-cut.

A first stop member 7 is arranged to be movable in the vertical groove 5c and through a hole in a top portion of the first rail 1. A second stop member 8 is arranged to be movable in the vertical groove 6c and through a hole in a top portion of the second rail 2. The stop members are thus arranged to be moved at an essentially right angle relative the rails. The first and second stop members 7, 8 have a length such that they extend into the corresponding rails down to approximately 50% of the height of the rails when the rails are not arranged end-to-end. The first and second stop members 7, 8 each have cylinder-shaped bodies. In other embodiments, the stop members may have for example plate-shaped bodies or bodies having a rectangular cross- section. A second engaging member 9 and a fourth engaging member 10 each comprise a wheel portion attached to a corresponding stop member 7, 8 at right angles via an axle portion. In other embodiments, the second and fourth engaging members may comprise a pin or stud portion instead of the wheel portion. The second and fourth engaging members 9, 10 are pointing in opposite directions, at right angles away from the front surfaces 5a, 6a of the first and second engaging members. The axle portions are resting against lower portions of the vertical grooves 5c, 6c. The stop members 7, 8 will remain in this blocking position by means of gravitational force as long as the rails are not arranged end-to-end.

Fig 2 shows the same embodiment of the suspended rail system as in fig 1 . In fig 2, the rails are mutually aligned or in an end-to-end position, i.e. the end surfaces 3, 4 are facing each other. The wheel portions of the second and fourth engaging portions 9, 10 have previously to arriving at the shown position, i.e. the highest positions in respective grooves 5b, 6b, run in the grooves and followed their rise to the present elevated position. Because the stop members 7, 8 are attached to the second and fourth engaging members, the stop members are also in elevated positions and do not extend into the rails 1 , 2. Thereby, both rails 1 , 2 are un-blocked and a transfer or transition of a trolley from the first to the second rail or vice versa is possible. Because of the different rise of the groove 16b compared to the groove 15b, the wheels of the second and fourth engaging members are prevented from colliding. Fig 3 shows the same embodiment of the suspended rail system as in figures 1 and 2. In fig 3, the rails are no longer mutually aligned or in an end-to-end position. The end surfaces 3, 4 are partially overlapping or facing each other, but are not sufficiently aligned to allow a transfer or transition. The wheel portions are halfway up the grooves 5b, 6b. Therefore, the stop members 7, 8 are in a partially elevated position, but extend sufficiently into the rails 1 , 2 in order to block a trolley from accidentally leaving either of the rails.

Fig 4 shows a suspended rail system according to another embodiment of the invention. The rails 1 1 , 12 are of the same type described above and as shown in figures 1 -3. In fig 4, the rails are not mutually aligned or in an end- to-end position, i.e. the end surfaces 13, 14 are not facing each other. On top of the first rail 1 1 , a first engaging member 15 is attached, and on top of the second rail 12, a third engaging member 16 is attached. The first and second engaging members 15, 16 have T-shaped cross-sections as seen from above, and have plane front surfaces 15a, 16a which are adapted to face each other when the rails 1 1 , 12 are arranged in an end-to-end position. The front surfaces 15a, 16a are at right angles with the direction of extension of the rails. The T-shaped cross-section is chosen to ensure stable

attachment possibilities to the rails and the shape may be chosen in any appropriate way as realized by the person skilled in the art. The engaging members 15, 16 each have a groove 15b, 16b cut into the front surfaces 15a, 16a. The grooves 15b, 16b have a Gaussian-shaped extension and start and end on either side of respective engaging members 15, 16. The grooves have a rectangular cross-section with a depth which is approximately one-third of the width. The groove 16b has the same shape as the groove 15b, and the grooves are vertically offset relative each other. The groove 16b is thus offset at a higher position compared to the groove 15b.

The first and second engaging members furthermore each have a vertical groove 15c, 16c cut into the front surfaces 15a, 16a. The vertical grooves 15c, 16c are deeper than the Gaussian-shaped grooves 15b, 16b, and extend partially along the height of the first and second engaging members, leaving a lower portion of the front surfaces 15a, 16a un-cut.

A first stop member 17 is arranged to be movable in the vertical groove 15c and through a hole in a top portion of the first rail 1 1 . A second stop member 18 is arranged to be movable in the vertical groove 16c and through a hole in a top portion of the second rail 12. The stop members are thus arranged to be moved at an essentially right angle relative the rails. The first and second stop members 17, 18 have a length such that they extend into the corresponding rails down to approximately 50% of the height of the rails when the rails are not arranged end-to-end. The first and second stop members 17, 18 each have cylinder-shaped bodies. A second engaging member 19 and a fourth engaging member 1 10 each comprise a wheel portion attached to one of the stop members 17, 18 at right angles via axle portions. The second and fourth engaging members 19, 1 10 are pointing in opposite directions, away from the front surfaces 15a, 16a of the first and second engaging members. The axle portions are resting against lower portions of the vertical grooves 15c, 16c. The stop members 17, 18 will remain in this blocking position by means of gravitational force as long as the rails are not arranged end-to-end.

Fig 5 shows the same embodiment of the suspended rail system as in fig 4. In fig 5, the rails are mutually aligned or in an end-to-end position, i.e. the end surfaces 13, 14 are facing each other. The wheel portions of the second and fourth engaging portions 19, 1 10 have previously to arriving at the shown position, i.e. the highest positions in respective grooves 15b, 16b, run in the grooves and followed their rise to the present elevated position. Because the stop members 17, 18 are attached to the second and fourth engaging members, the stop members are also in elevated positions and do not extend into the rails 1 1 , 12. Thereby, both rails 1 1 , 12 are un-blocked and a transfer or transition of a trolley from the first to the second rail or vice versa is possible. Because of the vertical offset between the grooves 15b, 16b, the wheels of the second and fourth engaging members are prevented from colliding.

Fig 6 shows the same embodiment of the suspended rail system as in figures 4 and 5. In fig 6, the rails are no longer mutually aligned or in an end-to-end position. The end surfaces 13, 14 are partially overlapping or facing each other, but are not sufficiently aligned to allow a transfer or transition. The wheel portions are halfway up the grooves 15b, 16b. Therefore, the stop members 17, 18 are in a partially elevated position, but extend sufficiently into the rails 1 1 , 12 in order to block a trolley from accidentally leaving either of the rails.

Although exemplary embodiments of the present invention has been shown and described, it will be apparent to the person skilled in the art that a number of changes and modifications, or alterations of the invention as described herein may be made. In particular, the first and third engaging members may switch positions with the second and fourth engaging members, i.e. such that the second and fourth engaging members are attached to the first and second rail, respectively, and the first and third engaging members are attached to the liftable stop members and movable therewith. The person skilled in the art furthermore realizes that the exact shape of the engaging members is not limited to the embodiments shown above. Thus, it is to be understood that the above description of the invention and the accompanying drawing is to be regarded as a non-limiting example thereof and that the scope of the invention is defined in the appended patent claims.