ELEVATED WORKER SUPPORT PLATFORM WITH EXTENSION ASSEMBLY

Abstract

An elevated worker support platform includes a main platform and an extension assembly having a longitudinal sliding extension frame and an upwardly folding extension platform supported on the extension frame to provide a rigid underlying support to the extension platform while also enabling the platform to be supported at the same elevational as the main platform. A railing for use alongside the extension assembly may also be formed of rigid sections that are foldable so that the railing can extend and retract with the extension platform. The main platform may be formed in sections spanning between upright columns in which cradles formed on the top of each column receive the platform section securely and in proper alignment therein until fasteners can more securely attach the platform sections to the columns.

Claims

1. An elevated platform assembly comprising: a main frame including a plurality of upright columns; a main platform supported at an elevated location on the upright columns, the main platform having an upper supporting surface arranged to receive workers supported thereon; an extension frame extending in a longitudinal direction between a proximal end and a distal end of the extension frame, the extension frame being supported on the main frame for translating movement in the longitudinal direction relative to the main frame between an extended position in which the proximal end is adjacent to the main frame and the distal end protrudes outwardly relative to the main frame and a retracted position in which the distal end is nearer to the main frame than in the extended position; and an extension platform supported on the extension frame, the extension platform including a first panel adjacent to the distal end of the extension frame and a second panel nearer to the proximal end of the extension frame than the first panel, the first panel being pivotally coupled to the distal end of the extension frame for pivoting about a first axis, the second panel being pivotally coupled to the main frame for pivotal movement about a second axis, and the first and second panels being pivotally coupled to one another about a third axis at an intermediate location between the first axis and the second axis; whereby the first and second panels are pivotal together with translating movement of the extension frame relative to the main frame between the extended position in which the first and second panels extend in the longitudinal direction so as to be arranged to receive said workers supported on an upper supporting surface of the first and second panels and the retracted position in which the third axis is displaced upwardly relative to the extended position such that the first and second panels are folded relative to one another into an upright orientation of the panels.

2. The assembly according to claim 1 further comprising rollers supported between the extension frame and the main frame to support the extension frame for said translating movement between the extended position and the retracted position.

3. The assembly according to claim 2 wherein the rollers include first rollers supported at the proximal end of the extension frame in rolling contact with the main frame and second rollers supported on the main frame in rolling contact with the extension frame between the proximal end and the distal end of the extension frame.

4. The assembly according to claim 1 wherein the extension platform includes two or more joists extending in the longitudinal direction of the extension frame in the extended position, each joist including a first joist section supporting the first panel thereon and a second joist section supporting the second panel thereon, the first and second joist sections defining the pivotal connections of the extension platform at the first axis, the second axis and the third axis.

5. The assembly according to claim 1 wherein at least a portion of at least one of the panels extends longitudinally beyond the third axis to be received within a corresponding recess in the other panel in the extended position.

6. The assembly according to claim 1 wherein a portion of each of the first panel and the second panel extends longitudinally beyond the third axis to be received within a corresponding recess in the other one of the first panel and the second panel in the extended position.

7. The assembly according to claim 1 wherein the distal end of the extension frame includes a first mating connector and a second mating connector thereon, wherein the first mating connector is arranged to mate with the second mating connector of a second elevated platform assembly of like configuration and the second mating connector is arranged to mate with the first mating connector of said second elevated platform assembly of like configuration, whereby the extension platforms of the elevated platform assemblies are arranged to be coupled to form a bridge between the main platforms of the elevated platform assemblies in the extended position.

8. The assembly according to claim 1 wherein the upper supporting surface of the first and second panels is substantially flush with the upper supporting surface of the main platform.

9. The assembly according to claim 1 further comprising: an intermediate frame supporting the extension frame relative to the main frame; the intermediate frame being supported on the main frame for translating movement in a lateral direction relative to the main frame in which the lateral direction is perpendicular to the longitudinal direction of the extension frame; and the extension frame being supported on the intermediate frame for said translating movement in the longitudinal direction relative to the intermediate frame.

10. The assembly according to claim 9 wherein the intermediate frame is supported on intermediate rollers in rolling contact with track members mounted in fixed relation to the main frame.

11. The assembly according to claim 9 further comprising a lateral drive motor operatively connected between the main frame and the intermediate frame so as to be arranged to drive movement of the extension frame in the lateral direction and a longitudinal drive motor operatively connected between the intermediate frame and the extension frame so as to be arranged to drive movement of the extension frame in the longitudinal direction, the lateral drive motor and the longitudinal drive motor being operable independently of one another.

12. The assembly according to claim 1 further comprising a gap panel pivotally supported on the main frame alongside the main platform to extend longitudinally of the extension frame towards the distal end of the extension frame in the extended position in interference with the displacement of the extension platform towards the retracted position whereby the gap panel is upwardly pivotal in response to displacement of the extension platform towards the retracted position.

13. The assembly according to claim 1 further comprising a railing extending in the longitudinal direction of the extension frame in the extended position, the railing comprising: a first railing post supported in fixed relation to the extension frame in proximity to the distal end of the extension frame; a second railing post supported in fixed relation to the main frame; and a railing member including a first section pivotally coupled to the first railing post about a first axis and a second section pivotally coupled to the second railing post about a second axis, wherein the first and second sections are pivotally coupled relative to one another about a third axis lying parallel to the first and second axes whereby the first and second sections of the railing member are pivotal together with translating movement of the extension frame relative to the main frame between the extended position in which the first and second sections extend in the longitudinal direction end to end with one another and the retracted position in which the first and second sections are folded relative to one another.

14. The assembly according to claim 1 further comprising: a plurality of main platforms, each main platform having (i) a platform frame including a plurality of rails extending longitudinally between ends of the rails at opposing ends of the main platform and (ii) an upper supporting surface arranged to support workers thereon, the main platforms being arranged to be supported at an elevated location on the upright columns such that the main platforms extend longitudinally end-to-end with one another; and a cradle mounted at a top end of each column in which the cradle has longitudinally opposing open ends and is at least partly open at a top of the cradle whereby the cradle is arranged to receive the ends of the rails of two corresponding ones of the main platforms inserted downwardly into the cradle; wherein each cradle further includes a primary fastener flange fixed thereon; and wherein one of the ends of each rail of the corresponding main platforms includes a secondary fastener flange fixed thereon and arranged to be fastened to the primary fastener flange of the corresponding cradle when the ends of the rails are received within the corresponding cradle.

15. An elevated platform assembly comprising: a main frame including a plurality of upright columns; a main platform supported at an elevated location on the upright columns, the main platform having an upper supporting surface arranged to receive workers supported thereon; an extension frame extending in a longitudinal direction between a proximal end and a distal end of the extension frame, the extension frame being supported on the main frame for translating movement in the longitudinal direction relative to the main frame between an extended position in which the proximal end is adjacent to the main frame and the distal end protrudes outwardly relative to the main frame and a retracted position in which the distal end is nearer to the main frame than in the extended position; an extension platform supported on the extension frame including one or more panels arranged to receive said workers supported on an upper supporting surface of the one or more panels in the extended position of the extension frame; and a railing extending in the longitudinal direction of the extension frame in the extended position, the railing comprising: a first railing post supported in fixed relation to the extension frame in proximity to the distal end of the extension frame; a second railing post supported in fixed relation to the main frame; and a railing member including a first section pivotally coupled to the first railing post about a first axis and a second section pivotally coupled to the second railing post about a second axis, wherein the first and second sections are pivotally coupled relative to one another about a third axis lying parallel to the first and second axes whereby the first and second sections of the railing member are pivotal together with translating movement of the extension frame relative to the main frame between the extended position in which the first and second sections extend in the longitudinal direction end to end with one another and the retracted position in which the first and second sections are folded relative to one another.

16. The assembly according to claim 15 wherein the first axis, the second axis, and the third axis are vertically oriented whereby the railing member is folded laterally outwardly from the extension platform in the retracted position of the extension frame relative to the extended position.

17. The assembly according to claim 15 further comprising: an intermediate railing post supported between the first railing post and the second railing post in pivotal connection with each of the first section and the second section of the railing member; and a lower member including a first section pivotally coupled to the first railing post below the first section of the railing member and a second section pivotally coupled to the second railing post below the second section of the railing member; wherein the first and second sections of the lower member are pivotally coupled to the intermediate railing post below the third axis; wherein the first axis, the second axis, and the third axis are horizontally oriented whereby the intermediate post is displaced upwardly and the railing member is folded upwardly in the retracted position of the extension frame relative to the extended position.

18. An elevated platform assembly comprising: a main frame including a plurality of upright columns; a plurality of main platforms, each main platform having (i) a platform frame including a plurality of rails extending longitudinally between ends of the rails at opposing ends of the main platform and (ii) an upper supporting surface arranged to support workers thereon, the main platforms being arranged to be supported at an elevated location on the upright columns such that the main platforms extend longitudinally end-to-end with one another; and a cradle mounted at a top end of each column in which the cradle has longitudinally opposing open ends and is at least partly open at a top of the cradle whereby the cradle is arranged to receive the ends of the rails of two corresponding ones of the main platforms inserted downwardly into the cradle; wherein each cradle further includes a primary fastener flange fixed thereon; and wherein one of the ends of each rail of the corresponding main platforms includes a secondary fastener flange fixed thereon and arranged to be fastened to the primary fastener flange of the corresponding cradle when the ends of the rails are received within the corresponding cradle.

19. The assembly according to claim 18 wherein the cradle provides support to the rail of the main platform received therein both vertically and laterally of the main platform, the assembly further comprising a fastener received through the primary and second fasteners flanges in which the fastener provides support to the rail of the platform primarily longitudinally of the main platform.

20. The assembly according to claim 18 wherein the cradle includes a pair of side flanges providing lateral support to the rail of the main platform received therein, the side flanges being oriented parallel to the primary and secondary fastener flanges located between the side flanges, and the side flanges having access openings formed therein through which fastening tools can be received to fasten a fastener through the primary and secondary fastener flanges.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0048] One embodiment of the invention will now be described in conjunction with the accompanying drawings in which:

[0049] FIG. 1 is a perspective view of the elevated platform assembly according to the present invention;

[0050] FIGS. 2 and 3 are perspective views of a bottom side of a first extension frame of the assembly in a retracted position;

[0051] FIG. 4 is a perspective view of a top side of the first extension frame of the assembly in the retracted position;

[0052] FIG. 5 is a perspective view of top side a second extension frame of the assembly in the extended position;

[0053] FIGS. 6 and 7 are perspective views of a bottom side of the second extension frame of the assembly in the extended position;

[0054] FIG. 8 is a perspective view of a lateral drive motor for driving movement of the second extension frame laterally of the extension frame relative to the main platform;

[0055] FIG. 9 is a perspective view of a railing of the first extension frame shown near the extended position;

[0056] FIG. 10 is a perspective view of the railing of the first extension frame shown in the retracted position;

[0057] FIG. 11 is a perspective view of a railing of the second extension frame shown near the extended position;

[0058] FIG. 12 is a perspective view of the railing of the second extension frame shown in the retracted position;

[0059] FIG. 13 is a perspective view of a bottom side of one of the main platforms supported on the columns of the main frame;

[0060] FIG. 14 is a perspective view of the cradle on the top end of one of the columns of the main frame; and

[0061] FIG. 15 is a perspective view of a plurality of different embodiments of the columns of the main frame.

[0062] In the drawings like characters of reference indicate corresponding parts in the different figures.

DETAILED DESCRIPTION

[0063] Referring to the accompanying figures there is illustrated an elevated worker support platform assembly generally indicated by reference numeral 10. The platform assembly 10 is particularly suited for supporting workers thereon at an elevated location spaced above a ground surface upon which the assembly is supported.

[0064] The assembly 10 generally includes a main frame 12 including a plurality of columns 14 which support a plurality of modular main platforms 16 thereon. In the illustrated embodiment, a first extension assembly 18 is supported at a first end of the main frame 12 and a second extension assembly 20 is supported at an opposing second end of the main frame. The main platforms 16 define a substantially continuous and level upper supporting surface 17 arranged to supporting the workers thereon.

[0065] The first extension assembly 18 in this instance includes an extension frame 22 that is supported on the main frame for translating movement in a longitudinal direction of the extension frame between an extended position protruding outwardly from the main frame and a retracted position in which the extension frame 22 is retracted inwardly into the main frame relative to the extended position. An extension platform 24 is supported on the extension frame to define an upper supporting surface 26 that is at the same elevation so as to be flush and substantially continuous with the upper supporting surface of the main platforms in the extended position. The extension platform 24 is upwardly foldable at a central hinge responsive to the extension frame being retracted inwardly into the retracted position as described in further detail below.

[0066] The second extension assembly 20 in the illustrated embodiment, includes the same extension frame 22 supporting the same extension platform 24 with an upper supporting surface 26 that is again at the same elevation so as to be flush and substantially continuous with the upper supporting surface of the main platforms in the extended position like the first extension assembly 18. The second extension assembly 20 differs from the first extension frame 18 by the addition of an intermediate frame 28 that supports the extension frame 22 on the main frame 12. The intermediate frame 28 is supported on the main frame for translating movement relative to the main frame in a lateral direction of the extension assembly (corresponding to a longitudinal direction of the main platforms 16), while in turn supporting the extension frame for translating movement relative to the intermediate frame 28 in the longitudinal direction of the extension assembly.

[0067] Each column 14 of the main frame 12 comprises a vertical post comprising a tube having a square cross-section in the illustrated example for spanning the full height of the column between a footing plate 30 at the bottom end of the column and the cradle 32 at the top end of the column. The footing plate 30 includes fastener apertures therein for securing the footing plate relative to the ground surface such as a foundation or floor of a building structure. The columns 14 are supported in pairs at spaced apart positions along the length of the main frame such that four columns 14 are provided at the four corners of each rectangular main platform 16. At intermediate locations along a length of the main frame 12 between adjacent main platforms, a single column may support the ends of both adjacent platforms thereon. At opposing ends of the main frame, two of the columns are spaced apart across the width of the main frame at one end of a corresponding one of the main platforms 16.

[0068] Each column 14 includes a set of ears 34 comprising upright flanges protruding outward from the post at a location spaced below the cradle 32 at the top end of the column onto which bracing members 36 can be secured. Each corresponding pair of columns 14 at opposing sides of the main frame may include a pair of vertically spaced apart ears 34 at the inner side of the column such that bracing members 36 supported in an intersecting manner in an X-shaped pattern can be secured to the ears 34 to fix the columns rigidly in parallel and spaced apart relation to one another. Additional ears 34 may be provided on opposing sides of each column in the longitudinal direction of the main platform such that additional bracing members 36 can be secured between each column and the one or more main platforms 16 supported thereon.

[0069] The cradle 32 at the top end of each column serves to receive a portion of the end of one or more main platforms 16 therein in an assembled configuration of the main frame such that the cradle provides vertical support and support in a lateral direction of the main frame to each of the main platforms received within the cradle. More particularly, each cradle 32 is a U-shaped trough having a horizontal bottom flange 38 and two side flanges 40 extending upward from laterally opposing sides of the bottom flange 38 to extend in the longitudinal direction of the main frame 12. Opposing ends of the cradle in the longitudinal direction of the main frame remain open. The cradle 32 is also open at the top across a length of the cradle, and is specifically open at longitudinally opposing ends of the cradle to receive a portion of each respective main platform 16 inserted downwardly through the open top of the cradle to be engaged upon the bottom flange 38 during assembly. When an end portion of each main platform 16 is received within a corresponding end of the cradle, the side flanges 40 contain the end portion of the main platform 16 therebetween in the lateral direction while the bottom flange 38 provides vertical support to the main platform engaged thereon.

[0070] A primary fastener flange 42 is fixedly mounted within the cradle 32 at a location which is laterally centred between the side flanges 40 while being parallel to the side flanges so as to be spaced from each of the side flanges. The fastener flange 42 is fixed to the bottom flange 38, for example by welding. The primary fastener flange 42 has a length in the longitudinal direction of the main frame which is shorter than the bottom flange 38 such that the bottom flange 38 protrudes longitudinally beyond the primary fastener flange 42 at both ends to define a ledge for receiving a corresponding portion of the main platform 16 on the protruding ledge.

[0071] As described in further detail below, secondary fastener flanges 44 are provided on the end portions of the main platform 16 that are received within the corresponding ends of the cradle 32. The secondary fastener flanges include fastener apertures therein for alignment with a faster aperture in the primary fastener flange 42 of the cradle 32 in an assembled configuration of the main platform. This enables a suitable joining fastener 46 to be inserted through the primary and secondary fastener flanges perpendicularly to the longitudinal direction of the main platform. To enable insertion and tightening of the fastener 46, access openings 48 are provided in each of the side flanges 40 in alignment with the apertures in the fastener flanges. The fastener 46 can thus be inserted horizontally through one of the access openings 48 for insertion through the cooperating apertures while a suitable nut can be inserted through the other access opening for assembling and tightening a bolted connection of the joining fastener 46. The access openings 48 are oversized relative to the fastener 46 to also enable suitable tools to be inserted through the access openings for tightening the fastener. Additional cap members (not shown) such as a rubber or plastic member, can be inserted into the access openings to close the access openings once fastening is complete and the access openings are no longer required. The cap members may be press-fit or snap fit into the access openings such that they can be readily removed as required for access to the joining fastener 46. The fastener 46 provides support in the longitudinal direction of the main frame to retain the end portion of the main platform 46 supported on the respective ledge at the corresponding end of the cradle 32.

[0072] Each main platform 16 comprises two longitudinally extending rail members 50 spanning substantially the full length of the main platform adjacent laterally opposing sides. A plurality of crossbars 52 are fixedly joined between the rail members to extend perpendicularly to the rail members in parallel to one another at longitudinally spaced positions. One or more deck panels 54 are supported on the top side of the rail members and the crossbars to span across the width and the length of the main platform and to define a respective portion of the upper supporting surface 17 of the main platforms on the main frame 12. Along one side of the main platform from which the first and second extension assemblies protrude, the crossbars may include end portions protruding beyond the rail member 50 at the inner side such that a portion of the deck panels 54 are cantilevered at the side of the main platform.

[0073] Opposing ends of the rail members 50 protrude longitudinally beyond the crossbars 52 at opposing ends of the main platform such that the protruding end portion of each rail member 50 defines an end portion of the main platform 16 that is received within the corresponding end of one of the cradles 32 in the mounted position. Each rail member is a tube of rectangular cross-section having dimensions that closely fits the lateral dimension between the side flanges 40 of the cradle and the height of the side flanges 40.

[0074] The end of each rail member locates one of the secondary fastener flanges 44 thereon such that the secondary fastener flange 44 protrudes from the end of the rail member in a vertical orientation that is offset laterally slightly to one side of centre of the rail member in the lateral direction by approximately the thickness of the primary fastener flange 42. In this manner, when the end portions of two adjacent main platforms are received within a common cradle 32, the ends of the rail members 50 are supported on the ledges at opposing ends of the bottom flange 38 of the cradle while the secondary fastener flanges 44 of the two main platform 16 are laterally offset adjacent opposing sides of the primary fastener flange 42. A common fastener 46 can be inserted through the cooperating apertures in the fastener flanges so that a single fastener 46 can be used to secure the secondary fastener flanges 44 of two adjacent main platforms onto a corresponding column 14. At the junction of each adjacent pair of main platforms, for each of the main platforms each of the longitudinal rail members 50 at laterally opposing sides of the main frame are received within the cradles 32 of the respective columns 14 of a laterally spaced apart pair of the columns.

[0075] The column 14 described above is an intermediate column for use at the junction of two adjacent main platforms at an intermediate location along the length of the main frame 12. At opposing ends of the main frame, an end column 14A may be provided which only supports the end portion of one of the rail members 50 of a single main platform 16 thereon. In this instance, the bottom flange 38 is not required to protrude beyond the primary fastener flange 42 at one end of the cradle.

[0076] As further shown in FIG. 15, in yet further embodiments the column may be configured as a double intermediate column 14B which has protruding ledges at longitudinally opposed ends for receiving end portions of longitudinally adjacent main platforms inserted therein, however, the column in this instance differs from the intermediate column 14 described above in that the side flanges are spaced farther apart to receive end portions of two laterally adjacent rail members 50 of two main platforms that are laterally adjacent one another. Accordingly the end portions of four separate platforms can be received within the cradle in this instance. Two separate primary fastener flanges 42 are provided at laterally spaced positions for alignment with the laterally adjacent rail members in this instance.

[0077] In yet a further embodiment shown in FIG. 15, a double end column 14C is configured for receiving two laterally adjacent rail members 50 of two laterally adjacent main platforms 16 therein at one end similarly to the double intermediate column 14B, however, the bottom flange 38 does not protrude beyond the primary fastener flanges 42 at one of the longitudinally opposing ends of the cradle such that the cradle is intended to be mounted at one end of the main frame in the longitudinal direction of the main frame.

[0078] All embodiments of the columns include access openings 48 in the side flanges 40 to permit access to tools for fastening the secondary fastener flanges 44 of the main platforms onto the primary fastener flanges 42 of the cradle as described above.

[0079] Turning now to the first extension assembly 18 and the second extension assembly 20, the extension frame 22 in each instance includes two longitudinal frame members 56 formed of square tubing that extend substantially the full length of the extension frame in the longitudinal direction of the extension frame, corresponding to a lateral direction of the main frame 12. The longitudinal frame members 56 extend along opposing sides of the extension frame and are fixed relative to one another by a plurality of crossbars 58 connected between the longitudinal frame members 56 to define a ladder shaped frame extending in the longitudinal direction between an inner proximal end supported on the main frame 12 and an outer distal end which protrudes laterally outward from the main frame 12 so as to be positioned farther from the main frame than the proximal end in the extended position.

[0080] The extension frame is supported for translating movement in a longitudinal direction of the extension frame by a set of rollers including proximal rollers 60 at the proximal ends of the longitudinal frame members 56 respectively and distal rollers 61 that support the extension frame thereon towards the distal end of the extension frame.

[0081] The proximal rollers 60 are mounted at a fixed location on the extension frame for rolling movement about an axis oriented perpendicularly to the longitudinal direction. The rollers form a rolling contact with longitudinal track members 62 that are supported on the main frame. Each track member 62 has a channel member having a C shaped cross-section with an open side at the interior facing the opposing track member. The channel member of the track number 62 is supported alongside a square tubing member for added structural rigidity of the track member. The track members 62 extend in the longitudinal direction of the extension frame, corresponding to the lateral direction of the main frame, across the width of the main frame between the longitudinal rail members 50 at opposing sides of the main frame.

[0082] In the instance of the first extension assembly 18, the track members 62 are fixedly supported relative to the longitudinal rail members 50 of a respective one of the main platforms 16 upon which the extension assembly is supported. In the instance of the second extension assembly 20, the track members 62 are fixedly supported on the intermediate frame 28 which is in turn supported on a respective one of the main platforms 16 of the main frame for translating movement along the length of the main platform as described in further detail below.

[0083] The distal rollers 61 are supported at an inner side of the main frame from which the extension assemblies protrude so as to be fixed relative to the main frame in the lateral direction of the main frame, corresponding to the longitudinal direction of the extension assembly. One of the distal rollers 61 is aligned with each one of the longitudinal frame members 56 of the extension frame such that the frame members 56 are engaged upon the rollers and the rollers form a rolling contact with the frame members as the extension frame is longitudinally extended and retracted relative to the main frame.

[0084] A guide flange 64 extends downwardly from a bottom surface of each longitudinal frame member 56 of the extension frame along the length thereof at a location spaced inwardly from an outer side of the extension frame. The overall width in the lateral direction of the extension assembly between the outer sides of the guide flanges 64 is arranged to closely match the lateral spacing between a corresponding pair of the distal rollers 61 of the extension assembly such that the guide flanges are received at the inner sides of the pair of distal rollers 61 to assist in locating the extension frame in the lateral direction relative to the distal rollers 61. This ensures that the corresponding bottom surfaces of the longitudinal frame members 56 remain engaged upon the distal rollers 61 as the extension frame is extended and retracted relative to the main frame.

[0085] In the instance of the first extension assembly 18, an outer crossbar 66 is supported on the main frame 12 parallel and spaced below a corresponding rail member 50 of the main platform by a pair of vertical legs 68 connected between the outer crossbar and the rail member 50 at opposing ends of the outer crossbar. The outer crossbar 66 is mounted on the main frame to span across the width of the first extension assembly 18 in the lateral direction of the extension assembly. The distal rollers 61 are mounted on the legs 68 respectively which are spaced apart by a distance slightly greater than the lateral width of the extension frame to receive the extension frame between the legs in the lateral direction and between the outer crossbar below and the longitudinal rail member 50 above in the vertical direction.

[0086] In the instance of the second extension assembly 20 a similar outer crossbar 66 with legs 68 are formed as part of the intermediate frame 28 as described in further detail below. The distal rollers 61 in this instance are again supported on the legs 68 to support the extension frame for translating movement in the longitudinal direction of the extension assembly, corresponding to a lateral direction of the main frame 12.

[0087] Extension and retraction of the extension frame is controlled by a longitudinal drive motor 70 which drives rotation of a longitudinal screw 72. The drive motor 70 is supported on an inner crossbar 74 that is par of the main platform, or that is connected between the inner ends of the track members 62 of the extension assembly. Accordingly, the inner crossbar 74 is fixed to the main frame in the instance of the first extension assembly, but forms part of the intermediate frame 28 in the instance of the second extension assembly 20. The longitudinal screw 72 is directly mounted to the output of the motor at an inner end and is rotatably supported by a suitable bearing on the outer crossbar 66 at the opposing outer end. A follower member 76 is mounted on the bottom side of the extension frame 22 in proximity to the proximal end of the extension frame. The follower member 76 forms a threaded connection with the longitudinal screw 72 received therethrough. In this instance, when the longitudinal drive motor 70 drives rotation of the longitudinal screw in a first direction of rotation, the extension frame 22 is displaced longitudinally in a first direction, and when the longitudinal drive motor 70 drives rotation of the longitudinal screw 72 in a second direction of rotation, the extension frame 22 is displaced longitudinally in an opposing second direction.

[0088] The extension platform 24 of each extension assembly comprises a plurality of joists extending the longitudinal direction of the extension assembly at laterally spaced apart positions. Each joist is arranged for folding at a central location between a first section 78 of the joist at the outer or distal end of the extension frame 22 and a second section 80 at the inner or proximal end of the extension frame 22. In the illustrated embodiment, three joists are provided including a joist at each of the laterally opposing sides of the extension platform and at a central or intermediate location between the outermost joists.

[0089] The first section 78 of each joist is pivoted onto the extension frame at an outer end of the joist corresponding to the distal end of the extension frame for pivotal movement of the first section 78 about a first pivot axis. The second section 80 of each joist is pivoted relative to the main frame 12 at an inner end of the joist corresponding to the proximal end of the extension frame in the extended position for pivotal movement of the second section 80 about a second pivot axis relative to the main frame. The inner end of each first section 78 of each joist is pivotally coupled to the inner end of the corresponding second section 80 of that joist about a third pivot axis in which the first, second and third pivot axes are horizontal and parallel to one another while extending in a lateral direction of the extension assembly.

[0090] In the extended position of the extension assembly, the first section 78 and the second section 80 of each joist extend in the longitudinal direction of the extension assembly so as to be aligned longitudinally end to end with one another and such that the top edges of the first and second sections 78 and 80 lie in a common horizontal plane. The third axis at an intermediate location along each joist is spaced above a plane locating the first and second axes therein. In this manner, when the extension frame is retracted longitudinally inward into the main frame 12, and the first axis at the distal end of each joist is retracted inwardly towards the second axis at the proximal end of each joist, the third axis is urged upwardly to cause folding of the joists. In the resulting retracted position, the first and second axes are closer together while the third axis is spaced above the first and second axes by a greater distance than in the extended position such that the first and second sections of the joist extend upwardly and inwardly towards one another to a central apex with the upper edges of the joists lying in a generally upright orientation.

[0091] The extension platform 24 of each extension assembly further includes a first deck panel 82 fixedly supported on the first sections 78 of the joists and a second panel 84 fixedly supported on the second sections 80 of the joists such that the first and second panels 82 and 84 move with the joists between the extended and retracted positions. Each panel has an inner end which is stepped in profile across the width of the panel in the lateral direction such that each panel defines a long section 86 and a short section 88 in which the long section is longer in the longitudinal direction of the assembly section than the short section, and in which the long section 86 and the short section 88 are laterally adjacent one another across the width of the panel.

[0092] In the instance of the first panel 82, the short and long sections are aligned with one another at the outer or distal end of the extension platform and the long section 86 protrudes longitudinally inward beyond the third axis defining the folding axis of the platform, while the adjacent short section 88 is recessed in the longitudinal direction relative to the third axis. In the instance of the second panel 84, the short and long sections are aligned with one another at the inner or proximal end of the extension platform and the long section 86 protrudes longitudinally outward beyond the third axis while the adjacent short section 88 is recessed in the longitudinal direction relative to the third axis.

[0093] When extended, each longitudinal section 86 extends into the corresponding recess formed by the short section 88 of the other panel such that the first and second panels have respective upper supporting surfaces 26 which are substantially horizontal and continuous with one another while also being at the same elevation as the upper supporting surfaces 17 of the main platforms. The staggered length of the panels of the extension platform provides a staggered seam between the first and second panels at the folding axis between the panels.

[0094] When retracted, the first and second panels 82 and 84 are pivoted upwardly at the third axis together with the joists such that the resulting upper supporting surfaces of the panels extend upward in a generally upright orientation while occupying a much shorter distance in the longitudinal direction of the extension assembly.

[0095] Each of the first and second extension assemblies further includes a gap panel 90 which is hinged on the main frame about a hinge axis extending longitudinally of the main frame and perpendicularly to the longitudinal direction of the extension assembly. The gap panel 90 extends laterally outward of the main frame from the hinge axis to extend partly over the extension frame in the extended position. The gap panel 90 is positioned in interference with the folding joists of the extension assembly such that upward folding of the extension platform into the retracted position engages the outer edge of the gap panel and pivots the outer edge of the gap panel upwardly together with the retraction of the extension platform. The gap panel is freely pivotal relative to the main frame such that the gap panel returns to a horizontal orientation which is substantially flush and at the same elevation as the upper supporting surface of the main platforms and the extension platforms in the extended position while being automatically pivoted upwardly in response to displacement of the corresponding extension assembly into the retracted position.

[0096] The extension frame 22 of each extension assembly is further provided with a first mating connector 92 at the distal end of one of the longitudinal frame members 56 and a second mating connector 94 at the distal end of the other longitudinal frame member 56. In the illustrated embodiment, the first mating connector comprises a vertical flange with a central slot extending horizontally inward from the outer end of the flange, and the second mating connector comprises a horizontal flange with a central slot extending perpendicularly inward from the outer end of the flange. In this instance, each first mating connector 92 is arranged to form a mating connection with the second mating connector of another assembly in an interlocking manner by inserting the vertical flange of the first connector into the slot of the second connector while simultaneously inserting the horizontal flange of the second connector into the slot of the first connector. Each slot includes a mouth portion where the dimensions of the slot diverge outwardly to the distal end of the flange for guiding insertion of a mating connector into the slot when joining a first connector with a corresponding second connector.

[0097] When two elevated worker support platforms 10 are provided which are substantially identical to one another but mirror images of one another, positioned with their main frames 12 extending parallel and spaced apart from one another, the extension assemblies 18 and 20 of one platform assembly 10 can engage the extension assemblies of the other platform assembly 10 in the extended positions thereof at their respective distal ends. The engagement of the two first extension assemblies 18 with one another form a bridge between the main frames of the two platform assemblies 10. Likewise, the engagement of the two second extension assemblies 20 with one another form a second bridge between the main frames of the two platform assemblies 10.

[0098] When each extension assembly 18 or 20 of one platform assembly 10 engage the corresponding extension assembly of the other platform assembly, the first mating connector 92 of the extension assembly will interlock with the second mating connector 94 of the corresponding extension assembly and the second mating connector 94 of the extension assembly will interlock with the first mating connector 92 of the corresponding extension assembly. The interlocking connection serves to align the distal end of one extension assembly both horizontally and vertically relative to the distal end of the other corresponding extension assembly in the extended positions thereof.

[0099] Turning now more particularly to the second extension assembly 20, the intermediate frame 28 in this instance is generally comprised of the two track members 62 joined at their inner ends by the inner crossbar 74 and joined at their outer ends by the outer crossbar 66. The legs 68 connected between the outer ends of the track members 62 and the outer crossbar 66 spaced therebelow in this instance are further configured for supporting part of a railing assembly as described in further detail below.

[0100] To support the intermediate frame 28 for translating movement relative to the main frame, the main frame is provided with an inner track member 96 fixed onto the main frame below one of the longitudinal frame members 50 of the corresponding main platform. The inner track member 96 is a channel having a C-shaped profile which is open to the interior of the main frame. A set of inner rollers 98 are mounted at spaced apart positions across the inner crossbar 74 of the intermediate frame to form a rolling contact within the interior of the track member 96 to support the inner and of the intermediate frame 28 for movement longitudinally along the main platform.

[0101] An outer track member 100 is provided at the opposing outer side of the main frame to receive outer rollers 102 of the intermediate frame engaged thereon for rolling contact along the length of the outer track member 100. More particularly, the outer track member 100 is a beam which is supported parallel and space below one of the longitudinal rail members 50 of the main platform by a pair of vertical legs 104 extending between the beam and the rail member 50 at opposing ends of the beam. In the illustrated embodiment the beam forming the outer track member 100 spans substantially the full length of the longitudinal rail member 50 of the main platform.

[0102] The outer rollers 102 are rotatably supported at a fixed location on the outer crossbar 66 of the intermediate frame 28 at laterally opposing sides of the extension assembly for rolling engagement with a top surface of the upper track member 100. A pair of the outer rollers 102 may be provided at each of the laterally opposing sides of the extension assembly in which each roller 102 is stepped in profile to engage both an upper surface and a corresponding edge surface of the outer track member 100. The upper surface of the beam forming the outer track member is thus constrained in the longitudinal direction of the extension assembly between the stepped profiles of a corresponding pair of outer rollers 102.

[0103] A lateral drive motor 106 is provided for driving the lateral movement of the intermediate frame 28 and the second extension assembly 20 supported thereon along the length of a corresponding main platform. To transmit drive from the motor 106 to the intermediate frame, an endless drive member 108, for example a flexible belt or chain in a continuous loop, is supported alongside the beam forming the outer track member 100 to be rotatably engaged on one or more idler wheels 110 on the beam. An upper run 112 of the drive member 108 is uninterrupted along the length of the outer track member 100 and is connected by a suitable link member 114 to the outer crossbar 66 of the intermediate frame. The drive motor 106 is mounted at one end of the outer track member 100 and has a rotary output connected through a gear box 116 to a drive wheel 118 that meshes with the drive member 108. Rotating the drive motor in a first direction of rotation thus causes linear displacement of the connecting link 114 attached to the upper run of the belt to displace the intermediate frame 28 in a first linear direction, while rotating the drive member in a second direction of rotation causes linear displacement of the connecting link 114 to displace the intermediate frame in a second linear direction.

[0104] In the instance of the second extension assembly 20, the gap panel 90 extends the full length of the range of movement of the second extension assembly 20 in the lateral direction of the extension assembly relative to the main frame. The gap panel may be formed in one or more sections. In this instance when the extension platform is retracted into the retracted position, interference with the gap panel causes the entirety of the gap panel or the interfering sections of the gap panel to be automatically pivoted upwardly in response to the retracting extension platform.

[0105] Turning now to FIGS. 9 through 12, a first railing assembly 120 is shown supported on the first extension assembly 18 and a second railing assembly 122 is shown supported on the second extension assembly 20. In further embodiments however, a first railing assembly 120 may be provided on either one or both of the extension assemblies 18 or 20 and/or a second railing assembly 122 may be provided on either one or both of the extension assemblies 18 or 20.

[0106] The first railing assembly 120 shown in FIGS. 9 and 10 includes a distal railing post 124 which is fixed onto the distal end of the extension frame and a proximal railing post 126 which is fixed onto the outer crossbar 66 in proximity to the proximal end of the extension frame in the extended position thereof. The posts 124 and 126 are vertically oriented and parallel to one another. An additional intermediate post 128 is supported at an intermediate location partway between the distal railing post 124 and the proximal railing post 126 so as to be similarly vertically oriented and parallel to the other posts. The intermediate post 128 is connected to each of the distal and proximal railing posts 124 and 126 by a respective four bar linkage arrangement so that the intermediate post is movable relative to the distal and proximal railing posts in a vertical direction while remaining parallel to the posts.

[0107] An upper railing member is connected between the top ends of the posts and includes a distal section 130 pivoted at an outer end on the distal railing post 124 about a first pivot axis and a proximal section 132 pivoted at an outer end on the proximal railing post 126 about a second pivot axis. The inner ends of the distal section 130 and proximal section 132 are pivoted at opposing sides of the intermediate post 128 about respective third axes. All of the pivot axes are parallel to one another and horizontal in this instance.

[0108] A lower railing member 134 is similarly provided in connection between the posts to include a distal section between the distal railing post 124 and the intermediate post 128 and a proximal section between the intermediate post 128 and the proximal railing post 126. The sections of the lower railing member 134 are similarly pivoted about respective horizontal axes. The lower railing member 134 is pivotally coupled to each of the railing posts in proximity to the bottom end of the posts respectively.

[0109] In this instance, a first four bar linkage is formed by the distal railing post 124, the distal section of the lower railing member 134, the intermediate post 128, and the distal section 130 of the upper railing member. Likewise a second four bar linkage is formed by the proximal railing post 126, the proximal section of the lower railing member 134, the intermediate post 128, and the proximal section 132 of the upper railing member.

[0110] An intermediate railing member 136 is also provided in connection between the railing posts at an intermediate height partway between the upper railing member and the lower railing member. The intermediate railing 136 similarly includes a distal section pivoted between the distal railing post in the intermediate post and a proximal section pivoted between the intermediate post 128 and the proximal railing post 126. Each intermediate railing member 136 is further configured to be telescopically adjustable in length such that the intermediate railing member 136 does not provide any interference to the pivoting four bar linkage arrangements described above.

[0111] In the extended position, the railing members are generally horizontally oriented and the intermediate post is supported at substantially the same height as the distal railing post 124 and the proximal railing post 126. The pivotal connections of the intermediate post to each of the railing sections is situated slightly higher in elevation than the pivotal connections of the railing members to the distal railing post 124 and the proximal railing post 126. In this instance, when the extension frame is retracted inwardly from the extended position to the retracted position, the distal railing post 124 and the proximal railing post 126 are displaced towards one another so that the resulting compression to the railing members causes the pivotal connections to the intermediate post 128 to be urged upwardly. Once the retracted position has been reached, the intermediate post remains longitudinally centred between the distal railing post 124 and the proximal railing post 126, but the railing sections are folded so that the intermediate post 128 is higher in elevation and such that the distal and proximal sections of each railing member extend upwardly and inwardly to one another to reduce the overall length of the railing in the longitudinal direction of the extension assembly.

[0112] The second railing assembly 122 shown in FIGS. 11 and 12 also includes a distal railing post 124 fixed onto the distal end of the extension frame and a proximal railing post 126 which is fixed onto the outer crossbar 66 in proximity to the proximal end of the extension frame and the extended position thereof. The posts 124 and 126 are again vertically oriented in parallel to one another.

[0113] In this instance, a single railing member is connected between the distal railing post 124 and the proximal railing post 126 having a distal section 138 with an outer end pivoted on the distal railing post 124 about a first pivot axis and a proximal section 140 with an outer end pivoted on the proximal railing post 126 about a second pivot axis, wherein the inner ends of the distal section 138 and the proximal section 140 are pivoted relative to one another about a third pivot axis. All of the pivot axes are vertically oriented in this instance.

[0114] Each of the distal section 138 and the proximal section 140 comprises a rectangular frame having an upper rail 142 extending horizontally across the top end of the rectangular frame, a lower rail 144 extending horizontally across the bottom end of the rectangular frame, an inner leg 146 spanning the height between the upper rail and the lower rail at an inner end of the rectangular frame, and an outer leg 148 spanning the height between the upper rail in the lower rail at an outer end of the rectangular frame. The outer leg 148 at the outer end of each section 138 and 140 is pivotally coupled to the respective railing post at vertically spaced apart locations. Similarly the inner legs 146 of the sections 138 and 140 are pivotally coupled to one another at vertically spaced apart locations.

[0115] In the retracted position, the distal section 138 and the proximal section 140 are substantially coplanar and extend end to end with one another in the longitudinal direction of the extension assembly. In the retracted position, the inward displacement of the distal railing post 124 and the proximal railing post 126 relative to one another causes the pivotal connection between the distal and proximal sections of the railing member at the third axis to be displaced laterally outwardly relative to the extension assembly so that the railing member is folded at an intermediate location and each section of the railing member extends generally laterally outwardly of the extension assembly from the outer leg 148 to the inner leg 146 thereof.

[0116] Since various modifications can be made in the invention as herein above described, and many apparently widely different embodiments of same made, it is intended that all matter contained in the accompanying specification shall be interpreted as illustrative only and not in a limiting sense.