GB2521601A

GB2521601A - Access tower

Info

Publication number: GB2521601A
Application number: GB1322492.8A
Authority: GB
Inventors: John Timothy Stevens
Original assignee: BENJAMIN STEVENS
Current assignee: BENJAMIN STEVENS
Priority date: 2013-12-19
Filing date: 2013-12-19
Publication date: 2015-07-01
Also published as: GB201322492D0

Abstract

An access tower (100) comprises a work platform (120) and a support structure (130) to support the work platform (120). The support structure (130) comprises a plurality of cells (140) each defined by: upper and lower horizontal members (150) and first and second groups of collapsible members (160, 165) which define opposed first and second sides respectively of the support structure (130) and are configured to move from a collapsed orientation to an erected orientation. The support structure (130) collapses in the vertical direction over at least a part of its height. When erected, the first group of collapsible members (160) forms opposed first and second side rails (182, 184) of an inclined ladder (180) to allow a user to access the work platform (120). Also included is an access tower characterised by the locking mechanism of at least one of the cells. Also defined is an access tower characterised by a pivoting arm biased to erect the cell.

Description

TITLE: ACCESS TOWER

DESCRIPTION

The present invention relatcs to access towers and particularly but not exclusively to mobile free-standing access towers for providing a work platform raised from ground level, Figures I and 2 show a prior art access tower ID of the te disclosed in GB 2434396 comprising a work platform 20 with an erectable handrail 22 and a collapsible support structure 30 for supporting the work platfonn 20. The support structure 30 comprises a plurality of cells 40 each defined by horizontal upper and lower members 50 and collapsible vertical members 60 pivotable aboiLt cenual hinges 62 and connected to tipper and lower members 50 via pivotable joints 63 allowing the support structure 30 to collapse in the vertical direction over at least a part of its height and pairs of tension elements 70 extending obliquely across each cell 40, Each hinged member 62 is connected with a corresponding hinged member 62 on an opposed side of the support structurn by a horizontal member 64).

When in the erected configuration (as shown in Figures I and 2), work platform 20 is accessed by a user climbing up the inside of the tower (with the user &cing outwards) using horizontal members 50, 62 and passing through a hatch 24 in the floor of the work platform The present applicant has identified the need for an improved access tower overcoming or at least alleviating problems associated with use of the prior art structures.

In accordance with a first aspect of the present invention, there is provided an access tower comprising: a work platform; and a support structure for supporting the work platform, the support stnLcture eompnsmg a plurality of cells each defined by: upper and lower members which arc in use orientated substantially horizontally; and first and second groups of collapsible members defining opposed first and second sides (e.g. thrthest opposed sides in the case of an elongate work platform) respectively of the support structure and configured to move from a collapsed orientation when the cell is in a collapsed configuration to an erected orientation when the cell is in an erected configuration. whereby the support structure is collapsible in the vertical direchon over at least a part of its height; wherein in the erected orientation the first group of collapsible members forms opposed first and second side rails of an inclined ladder structure (e.g. inclined relative to the vertical direction) for allowing a user to climb up the slLpport stnLcture to access the work platfornt In one embodiment the ladder structure is inclined such that an upper part of the ladder structure extends laterally inward relative to a lower part of the ladder structure (e.g. to allow access to the work platform by climbing up the outside of the support structure).

Advantageously, such an arrangement allows a user to safely climb the access tower and step forwards onto the work platform, i.e. without the need to turn through 180 degrees as is the case in the prior art arrangement the work platform is behind the user when they reach the top of the support structure via the hatch.

In one embodiment, the access tower comprises at least one tension element extending obliquely across at least one cell. The at least one tension element may act to stabilise the at least on cell when in the erected orientation.

In one embodiment, when hilly erected the support structure has a height of at least 2 metres. For example, when fully erected the support structure may have a height of at least 3 metres.

In one embodiment, the ladder structure is inclined relative to verfical by 5-25 degrees. For example, the ladder structure may be inclined relative to vertical by 10-20 degrees.

In one embodiment, the work platform includes a floor part extending laterally outwardly beyond an uppermost part of the ladder structure and the floor part defines at least in part an access opening for a user to access the work platform (e.g. with the access opening facing a part of the ladder structure).

In one embodiment, the access opening extends through the floor part and through a lateral side of the work platform (e.g. with the opening extending from an end edge of the floor part to a location iii the floor part spaced from the end edge and additionally extending from the end edge of the floor part to a location in the lateral side of the work platform spaced forni the end edge). By extending the access opening through a lateral side of the work platform improved access may be provided to the work platform without increasing the size of the access opening extending through the floor part.

In one embodiment, the work platform includes a movable floor part (e.g. trapdoor) for covering at least a portion of the access opening after a user has passed through the access aperture.

In one embodiment, in at least one cell the first collapsible members when in the erected orientation extend from a first location on the upper member of the cell to a second location on the lower member positioned laterally outwardly beyond the first location (e.g. the first collapsible members are inclined relafive to the vertical direcfion). In one embodiment, the first collapsible members are inclined relative to the vertical direction by 5-25 degrees. For example, the first collapsible members may be inclined relative to the vertical direction by 10-20 degrees.

In one embodiment, the first group of collapsible members of a first cell are substantially parallel to the first group of collapsible members of an adjacent cell when each of the first and second groups of collapsible members are in the erected orientation.

In one embodiment, the first group of collapsible members of the first cell are substantially collinear with the first group of collapsible members of the adjacent cell when each of the first and second groups of collapsible members are in the erected orientation.

In one embodiment, the upper and lower members define at least one rung of the ladder structure extending between the first and second side rails.

In one embodiment, at least one rung of the ladder structure is provided vertically between the upper and lower members extending between the first and second side rails.

In one embodiment, a plurality of rungs are provided between the upper and lower members extending between the first and second side rails.

In one embodiment, the lower members of each cell extend laterally beyond the upper members of each respective cell.

In one embodiment, at least one cell comprises means (e.g. torsion means) for counteracting at least a part of the weight of a cell when the at least one cell is collapsed or erected.

In one embodiment at least one cell comprises a locking mechanism for preventing erection of the least one cell when the locking mechanism is engaged.

In one embodiment, the locking mechanism is thrther configured to prevent erection of a lower cell below the at least one cell when the locking mechanism is engaged (e.g. so that the cells can only be erected in a predetermined sequence starting with the upper cell).

In one embodiment, the locking mechanism is further configured to limit (e.g. substantially prevent) movement of an erectcd cell relative to an adjacent collapsed cell below the erected cell (e.g. to prevent tilting of a partially erected structure).

In one embodiment, the locking mechanism comprises a movable locking member defining a surfhce for abutting a part of the lower cell when the locking member is in a first configuration and for clearing the lower cell when in a second configuration.

In one embodiment, the locking member is pivotally movable between the first and second configurations.

In one embodiment, the locking member is securable in the second configuration.

In one embodiment, the lower cell comprises a further locking mechanism as previously defined, In one embodiment, the thither locking member comprises the part of the lower cell.

In one embodiment, the at least one cell is biased to move from the collapsed configuration to the erected configuration when the locking mechanism is disengaged (e.g. to allow self-erection of the at least one cell).

In one embodiment, die at least one cell is biased to move from the collapsed configuration to the erected configuration by an arm having a first ann part pivotally coupled to a first part of the support structure (e.g. a first part of the at least one cell) and a second ann part configured to movably engage a second part of the sLLpport structure opposed to the first part (e.g. second part of the at least one cell), the arm being biased to urge the opposed parts of the support structure (e.g. opposed parts of the at least one cell) apart by a biasing force.

In one embodiment, the arm is configured to assist in erecting a lowermost cell of the plurality of cells.

In one embodiment, the second ann part is a rotary part (e.g. wheel).

In one embodiment, the rotary part is configured to run in a retaining channel

S

defined by the second part of the support structure (e.g. by the second part of the at least one cell).

In one embodiment, the first and second parts of the support structure arc upper and lower parts respectively (e.g. the upper and lower members of the at least one cell).

In one embodiment, the or each tension element is flexible (e.g. a wire or a chain (e.g. with an elastic inner part)) or telescopic.

In one embodiment, the at least one tension element extends from one corner of a cell to another corner of the same cell.

In one embodiment each cell has at least two tension elements.

In one embodiment, the second group of collapsible members are substantially vertical when in the crcctcd orientation.

In one embodiment, the first and second groups of collapsible members are substantially horizontal when in the collapsed orientation.

In one embodiment, the first and second groups of collapsible members are hinged substantially at their midpoint to allow collapse to a substantially horizontal plane, In one embodiment, at least one cell further comprises locking means for selectively preventing hinged movement of the first and second gronps of collapsible members when the support structure is in the erected configuration.

In one embodiment, the footprint of the access tower is substantially the same when the support structure is in the erected or collapsed configuration.

In one embodiment the access tower further comprises at least one collapsible handrail which when erected extends above the work platform to provide a hand hold for a user standing on the work platfonn. When erected the collapsible handrail defines at least one lateral side of the work platfonn.

In accordance with a second aspect of the present invention, there is provided an access tower comprising: a work platform; and a support structure for supporting the work platfomi, the support structure comprising a plurality of cells each defined by: tipper and lower members which are in use orientated substantially horizontally: and collapsible members configured to move from a collapsed orientation when the cell is in a collapsed configuration to an erected orientation when the cell is in an erected configuration, whereby the support structure is collapsible in the vertical direction over at least a part of its height; wherein at least one cell comprises a locking mechanism for preventing erection of the least one cell when the locking mechanism is engaged, In one embodiment, the locking mechanism is further configured to prevent erection of a lower cell below the at least onc cell when the locking mechanism is engaged (c.g. so that the cells can only be erected in a predetermined sequence starting with the upper cell).

In one embodiment, the locking mechwiisni is further configured to limit (e.g. prevent) movement of an erected cell relative to an adjacent collapsed cell below the erected cell (e.g. to prevent tilting ofa partially erected structure).

In one embodiment, the locking member is securable in the second configuration.

In one embodiment, the lower cell comprises a thither locking mechanism as previously defined.

In one embodiment, the further locking member comprises the part of the lower cell.

In one embodiment, the at least one cell is biased to move from the collapsed configuration to the erected configuration when the locking mechanism is disengaged (e.g. to allow self-erection of the at least one cell). In this way, the entire structure (including handrails) may be quickly erected all from ground level.

In one embodiment. the at least one cell is biased to move from the collapsed configuration to the erected configuration by an arm having a first arm part pivotallv coupled to a first part of the support structure (e.g. a first part of the at least one cell) and a second arm part configured to movably engage a second part of the support structure opposed to the first part (e.g. second part of the at least one cell), the arm being biased to urge the opposed parts of the support structure (e.g. opposed parts of the at least one cell) apart by a biasing force.

In one embodiment, the second arm part is a rotary part (e.g. wheel).

In one embodiment, the rotary part is configured to run in a retaining channel defined by the second part of the support structure (e.g. by the second part of the at least one cell).

In one embodiment, the first and second parts of the support structure are upper and lower parts respectively (e.g. the upper and lower members of the at least one cell).

In accordance with a third aspect of the present invention, there is provided an access tower comprising: a work platform; arid a support structure for supporting the work platform, the support stnLctlLre compnsmg a plurality of cells each defined by: upper and lower members wInch are in use orientated substantially horizontally; and collapsible members configured to move from a collapsed orientation when the cell is in a collapsed configuration to an erected orientation when the cell is in an erected configuration, whereby the support structure is collapsible in the vertical direction over at least a part of its height; wherein the at least one cell is biased to move from the collapsed configuration to the erected configuration by an arm having a first arm part pivotally coupled to a first part of the support structure (e.g. a first part of the at least one cell) and a second arm part configured to movably engage a second part of the support structure opposed to the first part (e.g. second part of the at least one cell), the arm being biased to urge the opposed parts of the support structure (e.g. opposed parts of the at least one cell) apart by a biasing force.

In one embodiment, the arm is configured to assist in erecting a owemost cell of the plurality of cells.

In one embodiment, the second arm part is a rotary part (e.g. wheel).

In one embodiment, the first and second parts of the support structure are tipper and lower parts respectively (e.g. the upper and lower members of the at least one cell).

An embodiment of the present invention will now be described by way of example with reference to the accompaiiying drawings in which: Figure 1 is a schematic side view of a fully erected prior art access tower: FiglLre 2 is a schematic end view of the fully erected access tower of Figure 1; Figure 3 is a schematic side view of an access tower in accordance with an embodiment of the present invention when fully erected: Figure 4 is a schematic end view of the access tower of Figure 3 when ftilly erected; Figure 5 is a schematic side view of the access tower of Figure 3 when in a partly collapsed state with the two lowermost cells collapsed; Figure 6 is a schematic side view of the access tower of Figure 3 when fully collapsed; and Figure 7 is a schematic view of a locking mechanism of the access tower of Figure 3, FiglLres 3-6 show a mobile access tower 100 comprising an elongate work platform and a free-standing collapsible support structure 130 mounted on wheels 132 for supporting the work platform 120.

Support structure 130 comprises three (upper, middle and lower) stacked cells 140 each defined by: upper and lower members 150 which are in use orientated substantially horizontally; and first and second groups of elongate collapsible members 160, 165 defining opposed first and second sides respectively of the support structure 130 and configured to move from a collapsed orientation when the cell 140 is in a collapsed configuration to an erected orientation when the cell 140 is in an erected configuration.

With reference to Figure 3. the lower members of each cell 140 extend laterally beyond the upper members of each respective cell so that when in the erected orientation the first group of collapsibk members 160 (pivotally connected to the ends of each of the upper and lower members) together form opposed first and second side rails 182, 184 of an inclined adder structure 80 in which an upper part of the ladder structure extends lateral'y inward relative to a thwer part of the ladder structure for allowing a user to dhmb up support structure 130 to access the work platform by climbing up the outside of the support structure. As illustrated, each of the first group of collapsible members 160 are inclined by the same angle to vertical (approximately 16 degrees from vertical when the tower is positioned on a horizontal surface) with the collapsible members forming the first side rail 182 being substantially collinear and the collapsible members forming the second side nil 184 being substantially coflinear, Advantageous'y, such an arrangement allows a user to safely climb the access tower (e.g. whilst earning hand tools) and step fonvards onto the work platform, i.e. without the need to turn through 180 degrees as is the ease in the prior art arrangement the work platform is behind the user when they reach the top of the support stnLcture via the hatch. In contrast to the first group of collapsible members 160, when in the erected orientation the second group of collapsible members 165 are substantially vertical.

As shown in Figure 4, the upper and lower members 150 define a first set of rungs 186 of the ladder structure 180 extending between the first and second side rails 182, 184.

A second set of rungs 188 of the ladder structure 180 are provided vertically between the upper and lower members by horizontal members extending between the first and second side rails 1 82, 1 84, Work platform 120 includes a collapsible handrail 122 defining lateral sides 124 of the work platfonu 120 and providing a hand hold for a user standing on the work platform floor part 122. Work platform 120 further comprises a floor part 126 extending laterally outwardly beyond an lLppermost part of the ladder structure 180, the floor part 126 defining at least in part an access opening 128 extending through the floor part 126 and through a lateral side 124 of the work platform 120. A trapdoor (not shown) is provided for covering at least a portion of the access opening formed in the floor part 126 once a user has passed through the access aperture. By extending access opening 128 through a lateral side 124 of work platform 120 improved access may be provided to the work pintform 120 without increasing the size of the access opening extending through the floor part (i.e. with the access opening 128 being partially accessible in a horizontal direction), Opposed sides of each cell 140 include pairs of flexible ties 170 extending oMiquey across the cell 140 from one corner of the cell 140 to a diagonally opposed corner of the same cell. \When access tower 100 is erected flexible ties become taught to stabilise the support structure 130 allowing the access tower to support a work platform raised over 3 metres above ground height.

The first and second groups of collapsible members 160, 165 are hinged substantially at their midpoint by hinge joints 161, 162 and connected to the upper and lower members 150 by pivotal joints 152 to allow collapse to a substantially horizontal plane. Locking devices (not shown) may be provided for selectively preventing hinged movement of the first and second groups of collapsiMe members 161, 162 when the support structure is in the erected configuration.

Figure 5 shows access tower 100 in a partially collapsed state with the middle and lower cells 140 collapsed and Figure 6 shows access tower 100 in a filly coflapsed state with all three cells 140 collapsed. As will be apparent from the drawings, the footprint of the access tower 100 is substantially the same when the support structure 130 is in the erected, partially collapsed or collapsed configuration, Each of the collapsible members 160, 165 include a locking mechanism 200 as shown in Figure 7 comprising a pivotal locking member 202 with an anchor-profile defining a surface 204 for abutting a part of the lower cell 140 (e.g. a part 206 of a pivotal locking member 202' provided as part of the lower cell 140) when the locking member is in a first configuration and for clearing the lower cell 140 when in a second configuration. A locking arm 208 is provided on locking member 202 for propping locking member 202 in the second configuration. When engaged locking mechanism 200 prevents erection of the least one cell 140 and prevents erection of a lower cell below the at least one cell so that the cells can only be erected in a predetennined sequence starting with the upper cell.

Furthennore. the locking mechanism 200 is configured to substantially prevent movement of an erected cell relative to an adjacent collapsed cell below the crcctcd cell to prevent tilting of a partially erected structure.

Each cell 140 is biascd to move from the collapsed configuration to the erected configuration when the locking mechanism 200 is disengaged to allow sequential self-erection of each cell. In die upper and nuddle cells 140 the biasing action is provided by torsion springs 155 acring at each pivot joint 152, In the case of lower cell 140 (which is erected last and therefore bears the weight of the upper and middle cells) the biasing action is provided by both torsion springs acting at each joint and an arm (or prop) 210 having a first ann part 212 pivotafly coupled to a upper member of the lower cell and a second arm part 214 configured to movably engage the lower member of the lower cell, the arm 210 being biased by a spring 216 to urge the upper and lower members of the lower cell apart.

The second arm part 214 comprises a wheel 218 configured to run in a retaining channel 154 defined by the lower member of the lower cell.

In use outriggers/stabilisers 220 are deployed first to secure the access tower in position on the ground. Once the access tower is secured in posifion. the collapsible handrail 122 is raised by the user mid locking mechanisms 200 associated with upper cell are disengaged by the user to allow upper cell 140 to self-erect. Erecting the upper cell allows locking mechanisms 200 associated with the middle cell 140 to be disengaged by the user to allow the middle cell to self-erect, following which locking mechanisms 200 associated with the lower cell 140 may be disengaged by the user to allow the lower cell to self-erect to bring access tower 100 to its filly erected state. The cells are lowered in reverse order; locking mechanism 200 will automatically reengage when the cells are lowered and are locked by the locking mechanism on the cell above when the cell is collapsed.

Claims

Claims: 1, An access tower comprising: a work platform; and a support structure for supporting the work platform, the support structure comprising a plurality of cells each defined by: upper and lower members which are in use orientated substantially horizontally and first and second groups of collapsible members defining opposed first and second sides respectively of the support structure and configured to move from a collapsed orientation when the cell is in a collapsed configuration to an erected orientation when the cell is in an erected configuration. whereby the support structure is collapsible in the vertical direction over at least a part of its height; wherein in the erected orientation the first group of collapsible members forms opposed first and second side rails of an inclined ladder structure for allowing a user to climb up the support structure to access the work platform.
2, An access tower according to claim 1, wherein the work platform includes a floor part extending laterally outwardly beyond an uppermost part of the ladder structure and the floor part defines at least in part an access opening for a user to access the work platform.
3, An access tower according to claim 2, wherein the access opening extends through the floor part and throlLgh a lateral side of the work platform.
4. An access tower according to any of the preceding elaims wherein in at least one cell the first collapsible members when in the erected orientation extend from a first location on the upper member of the cell to a second location on the lower member positioned laterally outwardly beyond the first location.
5. An access tower according to any of the preceding claims. wherein the upper and lower members define at least one rung of the ladder structure extending between the first and second side rails.
6. An access tower according to any of the preceding claims, wherein at least one rung of the ladder structure is provided vertically between the upper and lower members extending between the first and second side rails.
7. An access tower according to any of the preceding claims, wherein the lower members of each cell extend laterally beyond the upper members of each respective cell.
8. An access tower according to any of the preceding claims, wherein at least one cell comprises means for counteracting at least a part of the weight of a cell when the at least one cell is collapsed or erected.
9. An access tower according to any of the preceding claims, wherein at least one cell comprises a locking mechanism for preventing erection of the least one cell when the locking mechanism is engaged.tO. An access tower according to claim 9. wherein the locking mechanism is thrther configured to prevent erection of a lower cell below the at least one cell when the locking niechanisni is engaged.11. An access tower according to claim 9 or claim 10, wherein the locking mechanism is further configured to limit movement of an erected cell relative to an adjacent collapsed cell below the erected cell.12. An access tower according to claim 10 or claim 11. wherein the locking mechanism comprises a movable locking member defining a surface for abutting a part of the lower cell when the locking member is in a first configuration and for clearing the lower cell when in a second configuration.13. An access tower according to claim 12, the locking member is pivotally movable between the first and second configurations.14. An acccss tower according to claim 12 or claim 13, wherein the locking member is seclLrable in the second configuration.IS. An access tower according to any of claims 10-14, wherein the lower cell comprises a further locking mechanism as previously defined.16. An access tower according to any of claims 10-15, wherein the further locking member comprises the part of the lower cell.17. An access tower according to any of claims 9-16, wherein the at least one cell is biased to move from the collapsed configuration to the erected configuration when the locking mechanism is disengaged.18. An access tower according to any of the preceding claims, wherein the at least one cell is biased to move from the collapsed configuration to the erected configuration by an arm having a first ann part pivotallv coupled to a first part of the support structure and a second arm part configured to movably engage a second part of the support structure opposed to the first part, the arm being biased to urge the opposed parts of the support structure apart by a biasing force.19. An access tower according to claim 18, wherein the arm is configured to assist in erecting a lowermost cell of the plurality of cells.20. An access tower according to claim 18 or claim 19, wherein the second arm part is a rotary part.21. An access tower according to claim 20, wherein the rotary part is configured to run in a retaining channel defined by the second part of the support structure.22. An access tower according to any of claims 18-2 1. wherein the first and second parts of the support structure are upper and lower parts respectively.23. An access tower comprising: a work platform; and a support structure for supporting the work platfonn, the support structure comprising a plurality of cells each defined by: upper and lower members which are in use orientated substantially horizontally; and collapsible members configured to move from a collapsed orientation when the cell is in a collapsed configuration to an erected orientation when thc cell is in an erected configlLratioa whereby the support structure is collapsible in the vertical direction over at least a part of its height; wherein at least one cell comprises a locking mechanism for prevenfing erection of the least one cell when the locking mechanism is engaged.24. An access tower according to claim 23, wherein the locking mechanism is further configured to prevent erection of a lower cell below the at least one cell when the locking mechanism is engaged.25. An access tower according to claim 23 or claim 24, wherein the locking mechanism is ffirther configured to limit movement of an erected cell relative to an adjacent collapsed cell below the erected cell.26. An access tower according to claim 24 or claim 25, wherein the locking mechanism comprises a movable locking member defining a surface for abutting a part of the lower cell when the locking member is in a first configuration and for clearing the lower cell when in a second configuration.27. An access tower according to claim 26, wherein the locking member is pivotallv movable between the first and second configurations.28. An access tower according to claim 26 or claim 27, wherein the locking member is securable in the second configuration.29. An access tower according to any of claims 24-2S, wherein thc lower ccli comprises a further locking mechanism as previously defined.30. An access tower according to any of claims 24-29, wherein the further locking member comprises the part ofthe lower cell.31. An access tower according to any of claims 23-30, wherein the at least one cell is biased to move from the collapsed configuration to the erected configuration when the locking mechanism is disengaged.32. An access tower comprising: a work platform; and a support structure for supporting the work platform, the support structure comprising a plurality of cells each defined by: upper and lower members which arc in use orientated substantially horizontally; and collapsible members configured to move from a collapsed orientation when the cell is in a collapsed configuration to an erected orientation when the cell is in an erected configuration, whereby the support structure is collapsible in the vertical direction over at least a part of its height; wherein the at least one cell is biased to move from the collapsed configuration to the erected configuration by an arm having a first ann part pivotally coupled to a first part of the support structlLrc and a second ann part configured to movably engage a second part of the support structure opposed to the first part, the arm being biased to urge the opposed parts of the support stnLcturc apart by a biasing force.33. An access tower according to claim 23. wherein the arm is configured to assist in erecting a lowermost cell of the plurality of cells.34. An access tower according to claim 33 or claim 34 wherein the second arm part is a rotary part.35. An access tower according to claim 34, wherein the rotmy part is configured to run in a retaining channel defined by the second part of the support structure.36. An access tower according to any of claims 32-35. wherein the first and second parts of the support structure are tipper and lower parts respectively.