Platform Hoist.

FIELD OF THE INVENTION

[0001] The present invention relates generally to hoists, and, more particularly, to a platform hoist removably attachable to conventional scaffolding structures typically used in the building construction and renovation industry.

BACKGROUND

[0002] Platform hoists of the prior art used in the building construction and renovation industry are typically useful for vertically hoisting construction workers and/or construction material at a desired height level relative to a structure under construction or renovation.

[0003] Platform hoists of the prior art often include a custom scaffolding structure equipped with a platform supporting frame that is vertically movable relative to, and along, a side portion of the scaffolding structure. The platform supporting frame is generally movable using a manually or electrically powered hoist means.

[0004] In other instances, the platform hoists are generally represented by an assembly removably attachable to a side portion of a stationary structure, such as a building wall or a temporary scaffolding on the construction site. These platform hoists generally include a vertically extending frame structure having attachment means adapted for attachment to side portions of the building wall or scaffolding, and a platform support frame that is vertically movable relative to the frame structure using, here again, a manually or electrically powered hoist means.

[0005] In yet other instances, the platform hoists generally include a horizontally extending platform support frame equipped with at least a pair of manually or electrically powered cable hoist means at each distal ends thereof. The distal ends of the hoist cables are securely attached to an anchoring structure on the top of a building. Thus, the platform support frame is vertically movable relative to the adjacent building.

[0006] These platform hoists of the prior art, while providing a means for vertically hoisting construction workers and materials, also generally entail one or more of the following disadvantages.

[0007] Platform hoists of the prior art often include complex structures that are generally expensive to purchase or rent, and are also time consuming to install and uninstall on a construction site.

[0008] Furthermore, the platform hoists having complex structures also generally imply relatively high manufacturing costs, as well as relatively high maintenance and repair costs for the final client.

[0009] Some of the platform hoists of the prior art are generally too heavy and cumbersome to be handled by a single person during installation and removal operations. [0010] These heavy and cumbersome platform hoist also often occupy a substantial amount of space in, for example, the cargo bed of a pickup truck which, in turn, generally does not leave much extra space for other important tools therein. They are also generally not sufficiently collapsible for stowing in the trunk of a compact car or equivalent.

[0011] Some of the platform hoists of the prior art that are attachable to existing scaffolding can also be relatively unsafe to operate as they could cause a fall if they become detached from the scaffolding.

[0012] Against this background, there exists a need for an improved platform hoist. An object of the present invention is to provide such a platform hoist.

SUMMARY OF THE INVENTION

[0013] The proposed platform hoist provides a convenient hoisting device usable, in cooperative relation with a conventional scaffolding structure and platform members, for vertically hoisting material and/or personnel to a desired height level relative to a construction or renovation site, or the likes.

[0014] In a broad aspect, the invention provides a platform hoist attachable to a scaffolding structure and usable for supporting a platform, the platform hoist comprising a telescopic element including a telescopic element first portion and a telescopic element second portion, the telescopic element first and second portions being substantially elongated and operatively coupled to each other so as to be substantially longitudinally movable relative to each other. The telescopic element second portion includes a second portion attachment selectively attachable to the scaffolding structure. The telescopic element first portion includes an actuating assembly, the actuating assembly including an actuating assembly attachment selectively attachable to the scaffolding structure and an actuator, the actuator being operatively coupled to the actuating assembly attachment to selectively vary a distance between the actuating assembly attachment and the actuator. The telescopic element first portion also includes a platform support for receiving the platform. Attaching the second portion attachment and the actuating assembly attachment to the scaffolding structure above the actuator and actuating the actuator to pull the actuating assembly attachment towards the actuator raises the telescopic element first portion relative to the telescoping element second portion and to the scaffolding structure.

[0015] In some embodiments of the invention, the actuating assembly includes an elongated flexible element and the actuator is a windlass for selectively winding the elongated flexible element therearound and unwinding the elongated flexible element therefrom, the actuating assembly attachment being secured to the elongated flexible element opposed to the windlass. In a specific example, the elongated flexible element is a cable.

[0016] In some embodiments of the invention, the actuating assembly attachment includes a hook.

[0017] In some embodiments of the invention, the telescopic element first portion includes a telescopic element first portion body and a safety catch mounted thereto.

[0018] In some embodiments of the invention, the safety catch includes a hook movable between a hook first position and a hook second position, wherein, with the platform hoist in an operative configuration adjacent the scaffolding structure, in the hook first position, the hook protrudes towards the scaffolding structure to selectively engage the scaffolding structure, and, in the hook second position, the hook is retracted from the scaffolding structure to clear the scaffolding structure and allow vertical movements of the telescopic element first portion along the scaffolding structure.

[0019] In some embodiments of the invention, the safety catch includes a hook rotatable about the telescopic element first portion body between a hook first position and a hook second position, wherein in the hook first position, the hook protrudes from the telescopic element first portion body in a direction substantially opposed to the platform support, and, in the hook second position, the hook protrudes from the telescopic element first portion body in a direction angled relative to an imaginary line joining the hook when the hook is in the hook first position and the platform support. For example, the hook protrudes substantially perpendicular to the platform support.

[0020] In some embodiments of the invention, the hook is biased towards the hook first position.

[0021] In some embodiments of the invention, the scaffolding structure includes a plurality of substantially vertical posts and a plurality of substantially horizontal members interconnecting the vertical posts, the safety catch defining a cam angled relative to the telescopic element first portion body for moving the hook from the hook first position to the hook second position when the hook is moved upwardly across one of the horizontal members and the cam abuts against the one of the horizontal members. [0022] In some embodiments of the invention, the platform hoist further comprises a ratchet configurable between an engaged configuration and a disengaged configuration, wherein, in the engaged configuration, the ratchet prevents lengthening movements of the telescopic element larger than a predetermined lengthening movement, and in the disengaged configuration, the ratchet allows lengthening movements of the telescopic element larger than the predetermined lengthening movement.

[0023] In some embodiments of the invention, the ratchet allows shortening movements of the telescopic element in both the engaged and disengaged configurations.

[0024] In some embodiments of the invention, the telescoping element first and second portions define respectively telescopic element first and second portion bodies, one of the telescopic element first and second portions bodies being substantially tubular and receiving part of an other one of the telescopic element first and second portions bodies thereinto, the other one of the telescopic element first and second portions bodies defining a plurality of notches located at locations longitudinally spaced apart from each other, the ratchet including a notch engaging member mounted to the one of the telescopic element first and second portions bodies so as to be movable between an extended position and a retracted position. In the extended position, the notch engaging member engages one of the notches and in the retracted position, the notch engaging member is retracted from the other one of the telescopic element first and second portion bodies to allow relative movements between the telescoping element first and second portions.

[0025] In some embodiments of the invention, the notch engaging member is biased towards the extended position and the notches each define a ramped surface and an abutment surface, the ramped surface being configured and sized to move the notch engaging member to the retracted position when the notch engaging member is in one of the notches and the telescopic element is shortened, the abutment surface being substantially transversal and configured and sized such that the notch engaging member abuts thereagainst when the notch engaging member is in the one of the notches to prevent lengthening of the telescopic element.

[0026] In some embodiments of the invention, the notch engaging member defines a handle for selectively manually moving the notch engaging member to the retracted position so as to move the ratchet to the disengaged configuration.

[0027] In some embodiments of the invention, the telescopic element first portion includes a guide protruding therefrom for engaging the scaffolding structure and guiding movements of the telescopic element first portion therealong.

[0028] For example the guide includes a pair of substantially parallel guiding plates.

[0029] In some embodiments of the invention, the telescopic element first portion includes at least two guides protruding therefrom and longitudinally spaced apart from each other for engaging the scaffolding structure and guiding movements of the telescopic element first portion therealong.

[0030] In some embodiments of the invention, the platform support defines a pair of transversally spaced apart platform retaining elements for receiving the platform therebetween. [0031] In some embodiments of the invention, the platform support is movable between a platform support short configuration and a platform support long configuration, the platform retaining elements being spaced apart from each other by a larger distance in the platform support long configuration than in the platform support short configuration.

[0032] In another broad aspect, the invention provides a method of using a pair of platform hoists as defined above in combination with the scaffolding structure, the scaffolding structure including a plurality of substantially vertical posts and a plurality of substantially horizontal members interconnecting the vertical posts. The method comprises: positioning each of the platform hoists along a respective one of the vertical posts with the telescoping members elongated such that the telescoping elements can be shortened; for each of the platform hoists, attaching the second portion attachment and the actuating assembly attachment to the scaffolding structure with the actuating assembly attachment above the second portion attachment, the platform supports being positioned so as to be substantially level with each other; installing the platform on the platform supports such that the platform extends between the platform hoists; and using the actuator of each of the platform hoists to pull on the actuating assembly attachments. Pulling on the actuating assembly attachments moves the telescoping element first portions upwardly, the platform being thereby raised along the scaffolding structure.

[0033] Advantageously, the platform hoist according to the present invention is manufacturable as a substantially small and lightweight, relatively simple to operate and substantially sturdy assembly than can be relatively easily handled and operated by a single person. [0034] The platform hoist offers up to four redundant safety devices that can satisfy among the highest safety standards in the construction industry during usage, as well as during installation and removal operations.

[0035] Other objects, advantages and features of the present invention will become more apparent upon reading of the following non-restrictive description of some embodiments thereof, given by way of example only with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 , in a front perspective view, illustrates a platform hoist in accordance with an embodiment of the present invention;

[0037] Figure 2, in a right side elevation view, illustrates the platform hoist shown in FIG. 1 ;

[0038] Figure 3, in a left side elevation view, illustrates the platform hoist shown in FIGs. 1 and 2;

[0039] Figure 4, in a front elevation view, illustrates the platform hoist shown in FIGs. 1 to 3;

[0040] Figures 5, in a rear elevation view, illustrates the platform hoist shown in FIGs. 1 to 4; [0041] Figures 6, in a right side elevation view, illustrates the platform hoist shown in FIGs. 1 to 5, the platform hoist being shown engaged along side portions of a conventional scaffolding structure;

[0042] Figures 7, in a front perspective environmental view, illustrates a pair of platform hoists as shown in FIGs. 1 to 6, the platform hoists being shown engaged along side portions of a conventional scaffolding structure and supporting an elongated platform extending horizontally therebetween;

[0043] Figures 8, in a top rear perspective, enlarged view, illustrates the platform hoist shown in FIGs. 1 to 7, the platform hoist being shown engaged along side portions of a conventional scaffolding structure for demonstrating the rotational movement of a safety catch part of the platform hoist when encountering an horizontal member part of the scaffolding;

[0044] Figures 9, in a top rear perspective, enlarged view, illustrates the platform hoist shown in FIGs. 1 to 8, the platform hoist being shown engaged along side portions of a conventional scaffolding structure for demonstrating the rotational movement of the safety catch when encountering a longitudinal crossbar member part of the scaffolding structure;

[0045] Figure 10, in a perspective view, illustrates a platform hoist in accordance with an alternative embodiment of the present invention; and

[0046] Figure 1 1 , in a perspective sectional view, illustrates a ratchet part of the platform hoist shown in FIG. 10. DETAILED DESCRIPTION

[0047] FIGS. 1 to 9 inclusively illustrate various aspects of a platform hoist 10 according to an embodiment of the present invention. As seen in Fig. 7, the platform hoist 10 is removably attachable to a vertical side portion of a conventional scaffolding structure 12 used in the building construction industry.

[0048] The terminology "substantially" is used in this document to denote variations in the thus qualified terms that have no significant effect on the principle of operation of the platform hoist 10. These variations may be minor variations in design or variations due to mechanical tolerances in manufacturing and use of the platform hoist 10. These variations are to be seen with the eye of the reader skilled in the art. Also, directional terminology such as top, bottom, upper, lower, and the like is used to clarify the present document and refers to orientations when the platform hoist 10 is used in a typical manner. However, this terminology should not be used to restrict the scope of the appended claims.

[0049] A conventional scaffolding structure 12 may generally include a plurality of spaced apart and parallelly disposed end sections 14 having a substantially square or rectangular configuration. Each end section 14 is generally represented by a substantially rigid assembly comprising a pair of parallelly disposed, substantially vertical posts 16 interconnected to one another through at least a pair of spaced apart substantially horizontal members 18. Additional vertical and horizontal auxiliary members 20 and 22 respectively, may further interconnect the various parts of the scaffolding structure 12.

[0050] Each parallelly disposed end section 14 are rigidly linked to one another through longitudinal crossbar members 24 using releasable attachment means such as, for example, conventional thumb screw and thumb nut combinations. The cross-member typically extend at an oblique angle relative to the horizontal.

[0051] The platform hoist 10 is typically usable in a pair engaged on a corresponding pair of spaced apart vertical posts 16 of the scaffolding structure 12, as illustrated in FIG. 7, for supporting and vertically hoisting a respective distal end of a sufficiently elongated platform 26 extending horizontally therebetween.

[0052] Typically, material and/or personnel may be loaded on the thus horizontally disposed platform 26 and then raised and lowered at a user desired height level relative to a structure or work site under construction or maintenance.

[0053] The various components of the platform hoist 10 are preferably made of a substantially rigid material, or combination of materials such as, for examples, steel, iron, aluminum, or the likes. The platform hoist 10 may be advantageously manufactured using common elongated structural members such as tubular members having circular, square or rectangular cross-sections, C, H or L-shaped elongated channels, and the likes. The telescopically and rotatably operable components of the platform hoist 10 may be advantageously suitably lubricated for a smooth operation during usage.

[0054] Referring to FIG. 1 , according to an embodiment of the present invention, the platform hoist 10 is represented by a relatively simple and lightweight assembly that generally includes a telescopic element 30. The telescopic element 30 is configurable between a telescopic element retracted configuration, as illustrated in FIG. 2 for example, and a telescopic element extended configuration (shown partially extended in FIG. 6). The telescopic element 30 includes a telescopic element first portion 32 and a telescopic element second portion 36, the telescopic element first and second portions 32 and 36 being substantially elongated and operatively coupled to each other so as to be substantially longitudinally movable relative to each other. The telescoping element first and second portions 32 and 36 define respectively telescopic element first and second portion bodies 33 and 37. The telescopic element first portion 32 defines opposed first portion upper and lower ends 34 and 48.

[0055] In some embodiments of the invention, the telescopic element first portion 32 is hollow, or tubular, and configured and sized for coaxially slidably engaging, through the first portion upper end 34 thereof a lower portion of the telescopic element second portion 36. However, other configurations of the telescopic element first and second portions 32 and 36 are possible.

[0056] Referring for example to FIG. 1 , the telescopic element second portion 36 includes a second portion attachment 40 selectively attachable to the scaffolding structure 12, and typically provided opposed to the telescopic element first portion 32, or, in other words, at the top of the telescopic element second portion body 37 when the platform hoist 10 is in use. The telescopic element first portion 32 includes a platform support 50 for at least partially supporting the platform 26. In some embodiments of the invention, the telescopic element first portion 32 includes a safety catch 44 mounted to the telescopic element first portion body, for example adjacent the first portion upper end 34. In some embodiments of the invention, the telescopic element first portion 32 includes a guide 46 protruding therefrom for engaging the scaffolding structure 12 and guiding movements of the telescopic element first portion 32 therealong. For example, the guide 46 is fork-like and configured and sized for freely slidably engaging a transversal portion of a vertical post 16. [0057] The platform support 50 is in some embodiments of the invention telescopically extendable. In these embodiments, the platform support 50 defines an upper horizontal edge 52 that is preferably provided with transversally (relative to the longitudinal axis of the telescopic element 30) spaced apart proximal and distal platform retaining elements 54 and 56 respectively for laterally securing thereon a transversal underside portion of the platform 26. The platform support 50 is movable between a platform support short configuration and a platform support long configuration, the proximal and distal platform retaining elements 54 and 56 being spaced apart from each other by a larger distance in the platform support long configuration than in the platform support short configuration

[0058] The telescopic element first portion 32 includes an actuating assembly 60. The actuating assembly includes an actuating assembly attachment 126 selectively attachable to the scaffolding structure 12 and an actuator 61 , the actuator 61 being operatively coupled to the actuating assembly attachment 126 to selectively vary a distance between the actuating assembly attachment 126 and the actuator 61.

[0059] Attaching the second portion attachment 40 and the actuating assembly attachment 126 to the scaffolding structure 12 above the actuator 61 and actuating the actuator 61 to pull the actuating assembly attachment 126 towards the actuator 61 raises the telescopic element first portion 32 relative to the telescoping element second portion 36 and to the scaffolding structure 12. A more detailed mode of operation of the platform hoist 10 is described hereinbelow.

[0060] The telescopic element second portion 36 is typically at least slightly longer than the telescopic element first portion 32 such that, when the telescopic element 30 is in a fully retracted configuration, a distal upper end portion thereof at least slightly protrudes longitudinally distally from the first portion upper end 34.

[0061] The extension of the telescopic element 30 is conventionally limited through a slightly diametrically oversized portion of the second portion lower distal end (not shown), in cooperative relation with a slightly diametrically undersized portion of the first portion upper end 34.

[0062] In some embodiments of the invention, the telescopic element first and second portions 32 and 36 are freely rotatatable relative to each other about their longitudinal axis.

[0063] The shape of the second portion attachment 40 is better understood with reference to the combination of Figs. 2 to 5. The second portion attachment 40 is generally hook-like and includes a hook proximal portion 64A extending substantially tangentially horizontally from an outer circumferential portion of the second portion upper end 42.

[0064] A hook intermediate portion 66A extends substantially perpendicularly from a distal end of the hook proximal portion 64A, and at an upwardly oriented angle of roughly between thirty (30) and sixty (60) degree relative to an imaginary horizontal plane. For example, the hook intermediate portion 66A extends at an upwardly oriented angle of roughly forty-five (45) degree relative to an imaginary horizontal plane.

[0065] A hook distal portion 68A is typically represented by a relatively short and substantially downwardly extending arched member at the distal end of the hook intermediate portion 66A. Furthermore, the inner edge of the arched configuration of the hook distal portion 68A substantially conforms to the outer circular surface of a horizontal member 18 of a conventional scaffolding structure 12.

[0066] Hook proximal portion 64A may substantially extend laterally distally from the telescopic element second portion 36 a distance of roughly between 5 cm (2 inches) and 20 cm (8 inches). Preferably hook proximal portion 64B extends about 10 cm (4 inches) therefrom.

[0067] Typically, the safety catch 44 is rotatably mounted along an upper end portion of the telescopic element first portion 32, and substantially proximally under the actuating assembly 60, which will be described further below.

[0068] The safety catch 44 includes a hook 45 movable between a hook first position and a hook second position. With the platform hoist 10 in an operative configuration adjacent the scaffolding structure 12, in the hook first position, the hook 45 protrudes towards the scaffolding structure 12 to selectively engage the scaffolding structure 12. In other words, in the hook first position, the hook 45 protrudes from the telescopic element first portion body 33 in a direction substantially opposed to the platform support 50. In the hook second position, the hook 45 is retracted from the scaffolding structure 12 to clear the scaffolding structure 2 and allow vertical movements of the telescopic element first portion 32 along the scaffolding structure. In other words, in the hook second position, the hook 45 protrudes from the telescopic element first portion body 33 in a direction angled relative to an imaginary line joining the hook 45 when the hook 45 is in the hook first position and the platform support 50. In a specific example, in the hook second position, the hook protrudes from the telescopic element first portion in a direction substantially perpendicular to the platform support 50. [0069] Typically, the hook 45 is rotatable about the telescopic element first portion 32 about an axis that is substantially parallel with the general longitudinal axis of the telescopic element 30 and which coincides with the general longitudinal axis of the telescopic element 30. Also, typically, hook 45 is biased towards the hook first position.

[0070] The safety catch 44 generally includes a rotatable tubular member 70. The rotatable tubular member 70 is relatively short and defines an inner diameter that is configured and sized for being coaxially freely rotatably mounted about a circumferential portion of the telescopic element first portion body 33, between a pair of parallelly disposed restraining ring members72 coaxially fixedly mounted substantially proximally to each end of the rotatable tubular member 70.

[0071] The safety catch 44 further generally includes the hook 45 that is substantially similar in configuration, size and shape as hook-like member of the second portion attachment 40 described above, except that the corresponding hook distal portion 88B is provided with an additional portion that extends substantially rectilinearly upwardly at a substantially oblique angle of between thirty (30) and sixty (60) degree relative to an imaginary horizontal plane. For example, hook distal portion 88B extends at an oblique angle relative to an imaginary horizontal plane of roughly forty-five (45) degree. Thus, the hook distal portion 88B generally defines a relatively rectilinear and elongated member, compared to hook distal portion 68A. Furthermore, the hook distal portion 88B extends perpendicularly in a T-shaped configuration at the distal end of a hook intermediate portion 86B.

[0072] Furthermore, the hook distal portion 88B defines an arc that has a cross- sectional diameter dimension that is relatively smaller than the cross-section diameter of a longitudinal crossbar member 24. The importance of this differentiated cross-section diameter between the hook distal portion 88B and the longitudinal crossbar member 24 will be demonstrated along with a detailed description of a preferred method of using the platform hoist 10 further below.

[0073] A longitudinal side portion of hook distal portion 88B that is substantially diametrically opposite the junction with the distal end of the hook intermediate portion 86B defines a cam 90 angled relative to the telescopic element first portion body 33 for moving the hook 45 from the hook first position to the hook second position when the hook 45 is moved upwardly across one of the horizontal members 18 or 22 and the cam 90 abuts against the one of the horizontal members 18 or 22, as best illustrated in FIG. 5.

[0074] Furthermore, underside portions of hook intermediate portion 86B and hook distal portion 88B, proximal the junction thereof, generally cooperatively form an underside engaging portion 92 that can engage a horizontal member 18 of the scaffolding structure 12.

[0075] Hook proximal portion 84B may substantially extend laterally distally from the rotatable tubular member 70 a distance of roughly between 5 cm (2 inches) and 20 cm (8 inches). For example, hook proximal portion 84B extends about 10 cm (4 inches) therefrom.

[0076] Furthermore, the hook distal portion 88B, and consequently the cam 90, may have an overall length of roughly between 5 cm (about 2 inches) and 20 cm (about 8 inches). For example, hook distal portion 88B has an overall length of about 12 cm (about 5 inches) therefrom.

[0077] The safety catch 44 further generally includes a handle 94 for manually rotatably operating the safety catch 44 about the longitudinal axis of the telescopic element first portion body 33.

[0078] For example, handle 94 is represented by a substantially rectilinear handle bar having a proximal end attached to, or otherwise integrally joined with, an outer surface portion of the rotatable tubular member 70 that is substantially diametrically opposite the junction of the hook 45 to the tubular member 70. The distal portion of the handle bar extends substantially perpendicularly therefrom, to form a substantially right-angle configuration relative to the hook proximal portion 84B, from which the hook intermediate portion 86B extends.

[0079] The safety catch 44 further includes a rotation abutment member 96 (seen in FIG 3) for limiting the coaxial rotational movement of the latter about the longitudinal axis of the telescopic element first portion 32.

[0080] As exemplified in the drawings, a rotation abutment member 96 may be represented by an elongated rotation abutment member extending longitudinally between both restraining ring members 72.

[0081] The rotation abutment member 96 is radially positioned, relative to the first member 32 such that when the safety catch 44 is rotated in a maximum clockwise direction, as observed from a top plan view thereof, the hook proximal portion 84B extends substantially parallelly, and in a substantially same direction, relative to a first prong member 98 of the guide 46, which will be described further below. For example, the rotation abutment member 96 may be configured, sized and radially positioned about the pair of restraining ring members 72 for abutting against a proximal side portion of the handle 94, as exemplified in the drawings.

[0082] Other equivalent configurations, sizes and radial positions of the rotation abutment member 96 relative to the rotation of the rotatable tubular member 70 are also possible for achieving the relative position between the hook proximal portion 84B and the first prong member 98.

[0083] Furthermore, the coaxial rotatable movement of the safety catch 44, about the longitudinal axis of the first member 32, is spring biased in a clockwise direction, as observed from a top plan view, such that the safety catch 44 rests substantially abuttingly biased against the rotation abutment member 96 in the absence of external constraints.

[0084] As exemplified in FIG. 5, the spring biased rotational movement of the safety catch 44, about the longitudinal axis of the first member 32, may be achieved through the use of an elongated traction coil spring 100. The traction coil spring 100 may have a first end attached to a side portion of the rotatable tubular member 70, and its distal opposite end sufficiently stretched around in a clockwise direction and attached to a distal radial position relative thereto, on an outer circumference portion of a restraining ring member 72.

[0085] Referring back to the set of FIGs. 2 to 5, some of the parts described below being only visible on some of these figures, the guide 46 defines a substantially fork-like member 102 extending substantially perpendicularly from the telescopic element first portion body 33 adjacent the first portion lower end 48. The fork-like member 102 defines a pair of parallelly disposed and laterally spaced apart prong members, namely a first prong member 98 and a second prong member 99, the first and second prong members 98 and 99 defining substantially parallel guiding plates. The lateral distance separating the first and second prong members 98 and 99 respectively, is sufficiently sized for substantially freely slidably engaging therebetween the diameter of a vertical post 16. The overall longitudinal length of the first and second prong members 98 and 99, relative to an inner end portion 104 therebetween, is slightly shorter than the transversal diameter dimension of a vertical post 16 fully engaged in the fork-like member 102, as best illustrated in FIG. 6.

[0086] Furthermore, the inner end portion 104 is spaced apart a predetermined distance from the first member 32, for distancing the latter from a vertical post 16 engaged in the fork-like member 102. Operational tests of the platform hoist 10 have shown that a predetermined distance that is roughly equivalent to the transversal diameter of a vertical post 16 of a conventional scaffolding structure 12 provided a substantially smoother vertical sliding travel and operation of the platform hoist 10 therealong than if there were no spaced apart distance therebetween.

[0087] As exemplified in drawings a relatively short tubular member is used as a spacer element. It is to be understood that any other equivalent element or structural configuration may be used as a spacer element.

[0088] In an alternate embodiment of a platform hoist (not shown in the drawings), the fork-like member 102 is directly attached to the first portion lower end 48, without an interceding spacer element therebetween.

[0089] In other alternate embodiments of a platform hoist (not shown in the drawings), a polymeric-type material such as, for example, Teflon® or the like, may cover the inner end portion 104 of the fork-like member 102, for enhancing the slidable properties of the fork-like member 102 along the vertical post16.

[0090] In yet another alternate embodiment of a platform hoist (not shown in the drawings), the inner portion of the fork-like member 102 is represented by the surface of telescopic element first portion body 33 adjacent the first portion lower end 48. Furthermore, a freely operable wheel element mounted on a transversal axis relative to the fork-like member 102 is embedded in a bore provided through the inner end portion 104 such that only a distal circumferential portion of the wheel slightly protrudes thereof. Thus, this embodiment provides a rolling element on which the inner longitudinal side portion of a vertical post 16, engaged within the fork-like member 102, may roll thereon.

[0091] It is important to note that an inner portion the hook proximal portion 64A of the second portion attachment 40, an inner portion of the hook proximal portion 84B of the safety catch 44, and the fork-like member 102, may all be substantially aligned for linearly engaging a vertical post 16 of a scaffolding structure 12, as best illustrated in FIGS. 8 and 9.

[0092] Furthermore, although the second portion attachment 40 and hook 45 have been configured such that they may be substantially vertically aligned above the first prong member 98 of the fork-like member 102, it is to be understood that both second portion attachment 40 and hook-like member 82B may be oppositely configured such that they may be vertically aligned above the second prong member 99 of the fork-like member 102. In the latter case, the direction of rotation, the spring biased urging force applied on the safety catch 44, and handle 94 must also be oppositely configured respectively.

[0093] As seen in FIG. 2, an example of platform support 50 includes a substantially elongated platform support member 1 10 having a proximal end attached to, or otherwise integrally joined with, a lower portion of the telescopic element first portion body 33. The opposite distal end of the platform support member 110 extends substantially perpendicularly from the telescopic element first portion body 33 to form an upper horizontal edge 52 for stably supporting the platform 26 thereon.

[0094] The platform support 50 further typically includes a platform support reinforcement member 1 12 extending between the first portion lower end 48 and the platform support member 1 10.

[0095] For example, the platform support member 110 is a substantially hollow tubular member that is configured and sized for coaxially slidably engaging through the distal end thereof a platform support extension member 1 14 in a telescopic configuration.

[0096] The platform support extension member 1 14 is longitudinally positionable, relative to the platform support member 1 10, between a retracted configuration and an extended configuration. When in an extended configuration, the platform hoist 10 may support a platform 26 having a transversal dimension that is relatively greater than the overall length of the platform support member 1 10. The platform support 50 is therefore movable between a platform support short configuration and a platform support long configuration.

[0097] Furthermore, the relative longitudinal movement of the platform support extension member 1 14 may be securely locked, for example through a manually operable handle screw 1 16 having its threaded distal end engaged in an upwardly extending threaded bore provided along an underside portion of the platform support member 1 0, proximal a distal end thereof.

[0098] Typically, both the platform support member 1 10 and the platform support extension member 1 14 have substantially square or rectangular cross-sections, as exemplified in the drawings, for providing substantially flat upper portions on which one or more platforms 26 may stably rest. It is to be understood that other shaped cross- sections are also possible.

[0099] As exemplified in the drawings, the proximal platform retaining element 54 may be represented by a relatively short member transversally attached to an upper portion of the platform support member 1 10 and substantially proximal the adjacent telescopic element 30. The distal platform retaining element 56 may be represented by another relatively short member perpendicularly upwardly extending from the distal end of the platform support extension member 1 4.

[00100] In an alternate embodiment (not shown in the drawings) of a platform hoist 10, the junctions between the telescopic element 30, the platform support member 10 and the platform support reinforcement member 1 12 are mounted on conventional manually removable pivot pins and pivot support bores combinations. Thus, a user may manually disassemble or partially collapse the platform support 50 such that the platform hoist 10 forms a substantially more compact format for convenient stowage purposes in, for example, the trunk of a compact car or equivalent.

[00101] The actuator 61 is rigidly mounted to the telescopic element first portion substantially adjacent the first portion upper end 34 and substantially in register with the platform support 50. For example, the actuator 61 is a windlass and the actuating assembly 60 includes an elongated flexible element 124 such as a rope, cable or in some embodiments, a chain or any other suitable element that can be wound around a windlass. The windlass is usable for selectively winding the elongated flexible element 124 therearound and unwinding the elongated flexible element 124 therefrom. The actuating assembly attachment 126 is secured to the elongated flexible element 124 opposed to the windlass.

[00102] As exemplified in the drawings, and as seen in FIG. 2 for example, the windlass may be manually operated and may include a base portion that is fixedly attached to the telescopic element 30 through a perpendicularly extending actuator support bracket 118.

[00103] Typically, a manually operated windlass may include a base frame 120, a cable coil element 122, an elongated cable 124 and a conventional hook 126, forming the actuating assembly attachment 126, attached at the distal end thereof. The cable coil element 122 is transversally rotatably mounted on the base frame 120, a rotatable handle 128 is transversally rotatably mounted on a side portion of the base frame 120, for rotatably operating the cable coil element 122 through typically an inner reduction gear element. A selectively operable locking lever 130 is mounted proximal the cable coil element 122, for selectively applying therewith a ratchet action, or a release action to the latter. [00104] The conventional hook 126 is preferably configured and sized for hooking transversally onto a horizontal member 18 of a scaffolding structure 12, or alternatively on an upper circumferential edge of a vertical pole member, as illustrated in FIGS. 6 to 9 inclusively.

[00105] It is to be understood that other types and configurations of actuators 61 may be used. For example, a relatively small and compact, electrically powered cable hoist (not shown in the drawings) may form the actuator.

[00106] The relative proportions and dimensions of the various components of the platform hoist 10 may be suitably configured and sized for a given application. For example, the various components of the platform hoist 10, as described above, may be suitably sized and configured such that the telescopic element 30, in its minimum retracted configuration, measures roughly one (1 ) meter in length (roughly 3.2 feet), and the laterally extending platform support 50, in its minimum retracted configuration, proportionally measures roughly 2/3 the minimum length of the telescopic element 30. Other relative proportions between the various components of the platform hoist 10 are also possible.

[00107] Furthermore, the various components of the platform hoist 10 are made of suitably configured and size, as well as substantially rigid materials for supporting a substantial load that is commonly hoisted on conventional scaffolding structures 12 on construction sites.

[00108] A preferred method of using a pair of platform hoists 10, as described above, in cooperative relation with a conventional scaffolding structure 12 and at least one sufficiently elongated platform 26, generally includes the following steps.

[00109] In a first step, a first platform hoist 10 is vertically positioned substantially along and proximally to a first, user selected, vertical post 16 of a scaffolding structure 12.

[00110] In a second step, the telescopic element second portion 36 is upwardly extended, so that the telescoping element 30 is elongated such that the telescoping element 30 can be shortened. Afterward, the second portion attachment 40 is securely hooked to a user selected, horizontal member 18 extending on the diametrically opposite side of the vertical post 16, relative to the telescopic element 30.

[00111] In a third step, the platform hoist 10 is positioned such that the proximal vertical post16 is engaged in the inner portions of the guide 46.

[00112] Thus, the telescopic element 30 is substantially vertically disposed at a slight angle proximally the vertical post 16, the relative small angle deviation wit the vertical being due to the laterally spaced apart relation of the fork-like member 102 of the guide 46, relative to the longitudinal axis of the telescopic element 30.

[00113] In a fourth step, the actuating assembly attachment 126 is attached to the scaffolding structure 12 with the actuating assembly attachment 126 above the second portion attachment 40, Typically, the actuating assembly attachment 126 is pulled upwardly and securely hooked to preferably a user selected, horizontal member 18 substantially above the platform hoist 10. This horizontal member 18 is for example the highest horizontal member 18 reachable by the hook 126 above the platform hoist 10. Alternatively, the hook 126 may be simply hooked to a circumferential upper edge of the vertical post 16. Alternatively, the fourth step described above may be executed prior to the second and third steps.

[00114] In a fifth step, a second platform hoist 10 is releasably engaged on a second user selected vertical post 16, typically located next to the left or right hand of the first selected vertical post 16, by following substantially the same steps one (1) to four (4) described above such that both platform hoists 10 have their platform support 50 substantially parallelly disposed at a same horizontal level.

[00115] In a sixth step, the elongated platform 26, or a plurality of side-by-side platforms 26, may be transversally positioned on top of the thus parallelly disposed pair of platform supports 50.

[00116] In a seventh step, material and/or personnel may be loaded on the elongated platform 26 and, alternatively by one user, or synchronously by two users, each actuating assembly 60 being suitably operated for substantially horizontally raising the platform 26. Pulling on the actuating assembly attachments 126 moves the telescoping element first portions 30 upwardly, the platform 26 being thereby raised along the scaffolding structure 12.

[00117] It is important to note that, by raising the platform 26, the cam 90 of each safety catch 44 eventually come into contact with a lower circumferential side portion of the next upwardly adjacent horizontal member 18 of the scaffolding structure 12. Once in contact therewith, each hook 45 is gradually rotated laterally outwardly, in a counterclockwise direction, as observed in a top plan view, due the oblique configuration of the cam 90 that is gradually upwardly urged against the horizontal member 18. [00118] Thus, as illustrated in FIG. 8, the hook 45 is forcibly rotated while cam 90 remains abuttingly spring biased against the horizontal member 18. As the platform 26 is still further raised, the lower distal end of the cam 90 is eventually raised above the corresponding horizontal member 18, at which point the hook 45 is spring rotated clockwise back to its initial position. Once the safety catch 44 is thus positioned above the horizontal member 18, the hook-like underside engaging portion 92 thereof serves as a fall-proof safety means.

[00119] The hook-like underside engaging portion 92 of the safety catch 44 may thus prevent a substantial downward fall of the concerned distal end of the elongated platform 26 in a situation where, for examples, there is a sudden malfunction of the actuating assembly 60, or worst, there is a sudden malfunction of both the actuating assembly 60 and the second portion attachment 40.

[00120] As the platform 26 is further raised, the safety catch 44 may also eventually encounter a proximal portion 131 of a longitudinal crossbar member 24 linking end sections 14 of the scaffolding structure 12, as illustrated in FIG. 9.

[00121] In this particular case, the counterclockwise rotation of the hook 45 is a consequence of the cam 90 that is gradually upwardly urging against a lower circumferential portion of the longitudinal crossbar member 24.

[00122] It is important to note that, with the hook distal end 88B having a cross- sectional diameter dimension that is relatively smaller than the cross-diameter of a longitudinal crossbar member 24, cooperatively with the upper distal end of the hook distal end 88B being substantially proximal the adjacent vertical post 16, the upper end of the cam 90 will have a tendency to slip laterally outwardly relative to the centered longitudinal axis of the longitudinal crossbar member 24. Thus the hook 45 will consequently rotate counterclockwise substantially further than when the latter encounters a horizontal member 18.

[00123] Finally the lower distal end of the cam 90 is raised above the corresponding upper portion of the longitudinal crossbar member 24. Hence, the safety catch 44 is spring biased clockwise back to its initial position, with the hook-like member proximal portion 84B substantially proximal to, or abutting against, the vertical post 16.

[00124] Optionally in an eighth step, and once the telescopic element 30 substantially reaches its fully retracted configuration, the telescopic element second portion 36 is upwardly extended and suitably manually rotated to finally securely engage the second portion attachment 40 on preferably the highest horizontal member 18 it can reach.

[00125] From then on, the platform 26 may still be gradually and safely raised further by repeating steps seven (7) and eight (8) above.

[00126] To gradually lower the platform 26, in a ninth step, the actuators 61 of both platform hoists 10 are operated to gradually horizontally lower the platform 26, while the second portion attachment 40 and the hook 45 are manually rotated counterclockwise and clockwise at suitable intervals such that the second portion attachment 40 and the hook 45 avoid the horizontal members 18 as the telescopic element 30 moves down.

[00127] Referring to Fig. 10, there is shown a platform hoist 210 in accordance with another embodiment of the invention. The platform hoist 210 is similar to the platform hoist 10 and only the major differences therebetween are described herein.

[00128] A first difference resides in the second portion attachment 240 that takes a different shape. The second portion attachment 240 includes a generally U-shaped member 241 dimensioned to receive thereinto an horizontal member 18. The U-shaped member 241 opens horizontally and defines a gap 243 leading thereinto. A catch 247 is pivotally mounted to the U-shaped member 241 adjacent the gap 243 to selectively allow access therethrough by being selectively in register with or retracted from the gap 243. The catch 247 is shaped so as to only pivot inwardly, so that once an horizontal member 18 is received in the U-shaped member 241 , accidental movement out of the U- shaped member 241 is unlikely.

[00129] A second difference resides in the safety catch 244 that takes the form of a hook 245 defining a substantially U-shaped recess 249 opening in a direction leading towards the lower end of the platform hoist 210. The hook 245 is plate-shaped and defines a cam 257 extending at an angle relative to a longitudinal axis of the platform hoist 210. The hook 245 is attached to the telescopic element first portion body 33 through a spacing element 251 and is generally parallel to the U-shaped member 241 when the platform hoist 210 is secured to the scaffolding structure 12 and the hook 245 is in the hook first position. A pair of motion limiting pins 253 and 255 are provided to limit movements of the hook 245 towards the hook second position. The motion limiting pin 253 protrudes from the spacing element 251 and the motion limiting pin 255 is mounted to the telescopic element first portion body 33 fixedly relative thereto to interfere with movement of the motion limiting pin 253 once the motion limiting pin 253 reaches a predetermined rotation angle. [00130] A third difference resides in that the telescopic element first portion 232 includes two guides 246 protruding therefrom and longitudinally spaced apart from each other for engaging the scaffolding structure 12 and guiding movements of the telescopic element first portion therealong. The guides 246 have a function similar to that of the guide 46 and therefore have analog structure.

[00131] A fourth difference resides in the addition of another safety feature in the form of a ratchet 300, better seen in FIG. 1 1 , configurable between an engaged configuration and a disengaged configuration. In the engaged configuration, the ratchet 300 prevents lengthening movements of the telescopic element 230 larger than a predetermined lengthening movement. In the disengaged configuration, the ratchet 300 allows lengthening movements of the telescopic element 230 larger than the predetermined lengthening movement. Typically, the ratchet 300 allows shortening movements of the telescopic element 230 in both the engaged and disengaged configurations.

[00132] To that effect, one of the telescopic element first and second portions bodies 233 and 237, for example here the telescopic element first portion body 233, is substantially tubular and receives part of an other one of the telescopic element first and second portions bodies 233 and 237 thereinto, here the telescopic element second portion body 237. Reference to this specific case identifying the telescopic element first and second portions bodies 233 and 237 to tubular and received element is made for clarity reason herein below, but the inverse situation is also within the scope of the invention.

[00133] The telescopic element second portion body 237 defines a plurality of notches 302 located at locations longitudinally spaced apart from each other. The ratchet 300 includes a notch engaging member 304 mounted to the telescopic element first portion body 233 so as to be movable between an extended position and a retracted position. In the extended position, the notch engaging member 304 engages one of the notches 302 and in the retracted position, the notch engaging member 304 is retracted from the telescopic element second portion body 237 to allow relative movements between the telescoping element first and second portions 232 and 236. For example, the notch engaging member 304 takes the form of a pin extending through a suitably configured and sized aperture 306 formed in the telescopic element first portion body 233. Also, in some embodiments, a sleeve 308 extends from the aperture 306 to receive the notch engaging member 304.

[00134] Typically, the notch engaging member 304 is biased towards the extended position, for example through a biasing element such as coil spring 310 extending between a sleeve end member 312 terminating the sleeve 308 and a shoulder 315 defined by the notch engaging member 304. Also, typically, the notches 302 each define a ramped surface 314 and an abutment surface 316. The ramped surface 314 is configured and sized to move the notch engaging member 304 to the retracted position when the notch engaging member 304 is in one of the notches 302 and the telescopic element 230 is shortened, In other words, when the platform hoist 210 is in an operational configuration, the ramped surfaces 314 flare laterally outwardly when going up. The abutment surface 316 is substantially transversal and configured and sized such that the notch engaging member 304 abuts thereagainst when the notch engaging member 304 is in one of the notches 302 to prevent lengthening of the telescopic element 230. For example, the abutment surface 316 is generally parallel to the notch engaging member 304. In this configuration, the predetermined lengthening movement allowed with the ratchet 300 operational is the distance between notches 302.

[00135] Typically, the notch engaging member 304 defines a handle 318 for selectively manually moving the notch engaging member 304 to the retracted position so as to move the ratchet 300 to the disengaged configuration. This operation is necessary to lower the platform hoist 210. It should be noted that once the notch engaging member 304 has been moved to the retracted position, if the notches 302 do not occupy the entire circumference of the telescopic element second portion 236, rotating the telescopic element second portion 236 relative to the telescopic element first portion 232 will lock the notch engaging member 304 in the retracted position.

[00136] Returning to FIG. 10, another difference between the platform hoists 10 and 210 resides in the shape of the actuating assembly attachment 239 which include two substantially parallel plates 320 and 322, the plate 320 being shorter than the plate 322, interconnected by an interconnecting member 323. An end member 324 is provided at the end of the plate 322 and protrudes from the plate 322 such that a gap 336 is defined between the end member 324 and the plate 320. The gap 336 is dimensioned to receive one of the vertical posts 16 thereinto with the L-shaped member 324 abutting against one of the horizontal members 18. A crest 338 protrudes from the end member 324. A distance between the crest 338 and the interconnecting member 323 is such that the vertical post 16 fits with relatively little play therebetween. A bolt 340 extends between the plates 320 and 320, opposed to the end member 324, and is used to attach the the cable 124 thereto in a conventional manner.

[00137] Although the present invention has been described hereinabove by way of preferred embodiments thereof, it can be modified, without departing from the spirit and nature of the subject invention as defined in the appended claims.