Loading Platforms
This invention relates to loading platforms of the kind for use in the construction industry for extension and retraction from a building under construction.
According to the present invention there is provided a loading platform in which an elongate deck-carrying frame is carried by an elongate static-frame that is adapted to be secured to a floor of a building or other construction, the deck-carrying frame being mounted on the static-frame for longitudinal movement lengthwise of the static-frame for extension and retraction over an outboard end of the static-frame, wherein as part of the mounting of the deck-carrying frame for said movement, the underside of the deck-carrying frame runs on rollers that are carried by the static-frame at the outboard end.
The rollers carried by the static-frame may be rollers having flanges that engage with the deck-carrying frame to afford lateral guidance to the deck-carrying frame.
The deck-carrying frame may involve two elongate beams which run on the rollers carried by the static-frame, the two beams extending lengthwise of the deck-carrying frame either side of the deck. In these circumstances, the rollers carried by the static-frame may comprise two pairs of flanged rollers, and the two beams may then run on the two pairs of rollers respectively with each beam engaged between the flanges of its individual pair of rollers for lateral guidance. Also, the static-frame may involve two elongate beams that extend lengthwise of the static-frame either side of the deck-carrying frame, and in this case rollers carried by the beams of the deck- carrying frame may engage with the beams of the static-
frame for lateral guidance of the inboard end of the deck-carrying frame. These latter rollers may be rollers that have substantially vertical axes of rotation.
The beams of the deck-carrying and static-frames may be of I-section, and in these circumstances the beams of the deck-carrying frame mat nest respectively within those of the static-frame. Two side-mounted rollers having substantially horizontal axes of rotation may be mounted on each I-section beam of the deck-carrying frame at the inboard end of this frame. More particularly, the two side-mounted rollers may be located one above the other between the respective beam and the I-section beam of the static-frame with which it is nested, for rolling engagement with the top and bottom flanges of the latter beam. The vertical spacing between the two side-mounted rollers may be such that one or the other of them is in effective rolling-engagement with the respective top or bottom flange according to the extended or retracted condition of the deck-carrying frame.
A loading platform in accordance with the present invention will now be described, by way of example, with reference to the accompanying drawings, in which:
Figures 1 and 2 are, respectively, a plan view and sectional side elevation representative of the loading platform according to the invention the section of Figure 2 being taken on the line II-II of Figure 1;
Figure 3 is a sectional end elevation taken on the line III-III of Figure 2 showing details of side-mounted rollers and other features of the platform of Figures 1
Figure 4 is a sectional side elevation on the line I -IV of Figure 3, in further illustration of the side-mounted rollers of Figure 3 ;
Figures 5 and 6 are, respectively, a sectional end elevation and a side elevation showing details of further, support rollers of the platform of Figures 1 and 2, the section of Figure 5 being taken on the lines V-V of Figures 1 and 2 ;
Figures 7 and 8 are, respectively, a sectional end elevation and a side elevation showing details of a service roller of the platform of Figures 1 and 2, the section of Figure 7 being taken on the line VII-VII of Figure 2 ; and
Figure 9 is a sectional end elevation corresponding to Figure 5 showing details of a modification of the support rollers of the loading platform of Figures 1 and 2.
Referring to Figures 1 to 3 , a steel deck 1 of the loading platform is carried by an elongate, rectangular frame 2 that involves two spaced-apart and substantially- parallel beams 3. The beams 3 are rolled-steel joists of I-section, and are separated by a steel ladder-frame 4
(partially shown in Figure 3) that carries the deck 1 and to which the beams 3 are welded or bolted to form a rigid frame structure carrying the deck 1.
The deck-carrying frame 2 is mounted within an elongate static-frame 5 for longitudinal movement lengthwise of the frame 5 in extension and retraction from it. The frame 5 is formed by two substantially-parallel beams 6 which are interconnected by cross-beams 7 to 9 towards the front of the frame 5, and which towards its rear carry respective pairs of vertical props 10 and 11. The props 10 and 11 are for use in clamping the platform to a
floor of, for example, a multistorey building under construction, for safe extension and retraction from it. In this latter context, the frame 5 is laid flat on the floor of one level of the building and the props 10 and 11 are extended to engage the support-structure of the level above so as to clamp the frame 5 securely to the floor. The frame 5 is held securely in this way with its front end projecting partially from the building with the cross-beam 7 lipped over the outside edge of the floor.
The beams 6, like the beams 3 are rolled-steel joists of I-section but are of larger cross-section to enable the beams 3 of the deck-carrying frame 2 to nest within them on either side of the platform. In this respect, and as shown in Figure 3 and 4 for one side of the platform, each beam 3 is located with its upper and lower flanges 12 and 13 between the upper and lower flanges 14 and 15 of the respective beam 6.
Each beam 3 carries at the inboard end 16 of the frame 2, two rollers 17 that are mounted one above the other on the web 18 of the beam 3. The rollers 17 are mounted on the web 18 with their rotational axes horizontal, for rear-end support of the beam 3 nested within its respective beam 6. The two rollers 17 project through the flanges 12 and 13 respectively of the beam 3 for rolling engagement with the inside surfaces of the flanges 14 and 15 respectively of the beam 6 during longitudinal movement of the deck-carrying frame 2 lengthwise of the static-frame 5.
The frame 2 is supported forwardly from the rollers 17, from the underside, the support being provided by two pairs of flanged-rollers 19 that are mounted beneath the beams 3 respectively at the outboard end 20 of the frame 5; Figures 5 and 6 show the support provided by the pair of rollers 19 beneath the beam 3 on one side of the
platform. More particularly, the two pairs of rollers 19 are mounted on the static-frame 5 between its cross-beams 8 and 9 and just inside the two beams 6 respectively, with their rotational axes horizontal and co-linear. The rollers 19 of each pair project through the flange 15 of the adjacent beam 6, and the respective beam 3 runs on the roller-pair with the edges of its lower flange 13 engaged between the flanges 21 of the two rollers 19. The engagement of the flange 13 between the roller- flanges 21 provides lateral guidance of the deck-carrying frame 2 in maintaining it aligned with the static-frame 5 at its outboard end 20.
Further lateral guidance of the frame 2 within the frame 5 is maintained by rollers 22 which are mounted on the webs 18 of the beams 3 with their rotational axes vertical, and which run on the webs 23 of the beams 6. The rollers 22 are mounted just in front of the rollers 17 at the inboard end 16 of the deck-carrying frame 2 and in conjunction with the rollers 19 at the outboard end 20 of the static-frame 5, act to maintain alignment of the frame 2 within the frame 5 both during extension and retraction movement and also while the frame 2 is stationary in its extended or retracted condition.
The vertical spacing between the two rollers 17 of each beam 3 is such that when the frame 2 is extended fully or to a substantial extent, and during its movement into and out of that condition, the upper rollers 17 of the two beams 3 bear hard on the upper flanges 14 of the beams 6; the lower rollers 17 are then clear, or effectively clear, of engagement with the lower flanges 15. On the other hand, when the frame 2 is retracted and moving into and out of that condition, the lower rollers 17 bear hard on the flanges 15 of the beams 6, and the upper rollers 17 are clear, or effectively clear, of engagement with the flanges 14. The changeover of engagement from the
upper to the lower rollers 17, and vice versa , takes place with very minor, virtually unnoticeable, tipping of the frame 2 about the rollers 19, in re-balancing of loading on the frame 5.
The rollers 19 mounted at the outboard end 20 of the frame 5, take the place of side-mounted rollers corresponding to the rollers 17 and 22 that would according to known practice have been mounted on the webs 23 of the beams 6 to engage the beams 3 at the outboard end 20 of the frame 5. It is very difficult with rollers mounted between nested beams (such as the beams 3 and 6) at the outboard end of the static-frame, to clear them of building material which may become trapped between them and block easy movement of the deck-carrying frame; it normally requires dismantling of the platform installation. With the rollers 19 of the present invention mounted beneath the frame 2 , debris that might otherwise interfere with their free running, rather becoming trapped and causing a blockage, readily falls clear.
Also, there is the advantage with the mounting of the rollers 19 under the frame 2, that they give the frame 2 a more positive and robust, rolling support than is generally achievable using side-mounted rollers. Use of the rollers 19 obviates the need for accurate relative- positioning of side-mounted rollers between the nested beams 3 and 6, and also in relation to the rollers 17 and 22 at the inboard end 16 of the frame 2, that would otherwise be necessary to avoid twisting and possible jamming of the frame 2.
Furthermore, the rollers 19, in allowing for slight pivoting of the frame 2 in transfer of load between the upper and lower rollers 17 and 18, avoids the necessity for precise positioning of the rollers 17 relative to one
another, and allows tolerance for inside-surface irregularities of the flanges 14 and 15 of the beams 6. Moreover, the use of the flanged rollers 19 avoids the need for side-mounted rollers such as the rollers 22, to give lateral guidance at the outboard end 20, the flanges 21 of the rollers 19 providing very positive guiding- restraint on the two beams 3 to ensure alignment is maintained.
The platform of the invention also includes rollers 24 and 25 which are mounted with their rotational axes horizontal, at spaced positions from one another along each beam 6, and which are used to assist servicing of the platform. As illustrated by Figures 7 and 8 for the roller 25 on one side of the platform, the rollers 24 and 25 are mounted on the web 23 of the beam 6 between the beams 6 and 3 and just out of contact with the upper flange 12 of the beam 3. They remain out of contact with the flange 12 irrespective of the slight tipping of the frame 2 in either sense on the rollers 19 referred to above, until the frame 2 is retracted into the frame 5 to the extent that it leaves the rollers 19 and takes the rollers 17 and 22 beyond the rear ends of the beams 5. When retracted to this extent, the frame 2 tips slightly down to run on the rollers 24 and 25 and enable it to be moved to give ready access to the assembly of the rollers 19 for servicing and/or replacement as may be necessary. Furthermore, with the frame 2 pulled back in this way, the rollers 7 and 22 at the inboard end 16 are similarly, readily accessible.
The frame 2 can be returned from the rollers 24 and 25 to its fully operational condition on the rollers 19, and with the rollers 17 and 22 between the beams 3 and 6, simply by pushing it forward to run up onto the rollers 19.
Although not shown in the drawings, the platform is provided with the normal safety barriers to the deck 1 and along the sides of the frame 5. Additionally it is provided with facilities for locking the frame 2 in its extended and retracted positions, and for lowering a ramp portion 26 of the deck 1 when so locked.
The loading platform described above may be modified as illustrated in Figure 9. According to this modification, the pairs of flanged rollers 19 at the outboard end 20 of the frame 5 are replaced by un-flanged rollers 27, and lateral guidance of the beams 3 is afforded by a side- mounted roller 28 mounted on the web 23 of each beam 6.