FIELD The specification relates generally to construction, and specifically to a roof hoist.
BACKGROUND The construction of houses and other dwellings is an old and well-known art. The assembly of roofs on such dwellings poses several challenges, however. For instance, the construction of the roof is often delayed until the top story of the dwelling is at least partially completed in order to provide support for the roof. This results in increased construction time, since no progress can be made on the roof until a certain stage of the dwelling construction is reached. Further, building the roof generally requires workers to operate at significant heights, increasing the changes of injury in case of a fall. Compounding the problem, the roof generally begins as little more than a frame, providing scarce and unequal footing during the early stages of its construction.
It can therefore be desired to build a roof separately from the dwelling and later set it onto the dwelling. U.S. Pat. No. 6,253,504 (Cohen) describes a roof which may be secured to a hook using rope or cable. The roof may then be lifted onto a dwelling. This approach presents the difficulty of fitting the ropes or cables around a roof, as well as the difficulty of removing the ropes or cables once the roof has been set onto the dwelling.
SUMMARY An aspect of this specification provides an apparatus for lifting a roof, the apparatus having a plurality of hooks, each hook comprising a roof support member having a first end and a second end, the first end configured to extend underneath at least a portion of an edge of the roof, a stem, extending from the second end of the roof support member, the stem including a lift point; each of the hooks being arrangeable at the periphery of the roof to support at least a portion of the roof.
A further aspect of this specification provides a method for lifting a roof onto a dwelling, comprising positioning a roof hoist over the roof, the roof hoist having a plurality of hooks, each hook comprising a roof support member having a first end and a second end, the first end configured to extend underneath at least a portion of an edge of the roof; and a stem, extending from the second end of the roof support member, the stem including a lift point; engaging each of the plurality of hooks with a portion of the roof, operating the roof hoist to lift the roof via the plurality of hooks coupled thereto; and placing the roof on the dwelling.
A still further aspect of this specification provides an apparatus for lifting a roof, the apparatus having at least one connector, each connector comprising a first member having at least one wheel; a second member having at least one wheel; the first member being configured to receive a portion of a first beam; the second member being configured to receive a portion of a second beam; and the first member being stackably coupled to the second member, the first member and the second member thereby defining an intersection between the first beam and the second beam, when the first beam and the second beam are received in the first member and the second member respectively, the intersection being moveable along the first beam and the second beam by the at least one wheel of the first member and the at least one wheel of the second member.
BRIEF DESCRIPTION OF THE DRAWINGS Embodiments are described with reference to the following figures, in which:
FIGS. 1-3 depict a hoist according to a non-limiting embodiment, the hoist being positioned over a roof and being used to lift the roof,
FIG. 4 depicts a hoist according to a non-limiting embodiment lifting a roof;
FIG. 5 depicts an isometric view of the hoist of FIG. 4, according to a non-limiting embodiment;
FIGS. 6-7 depict the interaction between a leg of the hoist of FIG. 4 and the top of the hoist of FIG. 4, according to a non-limiting embodiment;
FIGS. 8-9 depict isometric and side views of a hook of the hoist of FIG. 4, according to a non-limiting embodiment;
FIGS. 10-11 depict isometric and side views of a tension connector of the hoist of FIG. 4, according to a non-limiting embodiment; and
FIGS. 12-13 depict isometric and side views of a compression connector of the hoist of FIG. 4, according to a non-limiting embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 depicts a roof hoist, indicated generally at 10. Roof hoist 10 includes a frame 14. Frame 14 is moveable along the ground, for example via a plurality of wheels 18, and may be positioned over a roof 22 as depicted in FIG. 2. The positioning of roof hoist 10 over roof 22 may be done after the construction of roof 22 is substantially completed. Roof hoist 10 also includes a plurality of hooks 26, which will be described in greater detail below, suspended from frame 14 by suspension lines 30. Suspension lines 30 may be cables, straps, ropes, or any other suitable suspension means. A portion of each hook 26 is slideable underneath roof 22, thereby engaging a portion of roof 22. Roof 22 is thus supported by the plurality of hooks 26. Roof 22 may rest on beams or posts 34, in order to raise roof 22 slightly from the ground and facilitate the positioning of hooks 26.
Roof 22 may then be lifted from the ground, the weight of roof 22 being supported by frame 14 via suspension lines 30 and hooks 26. As depicted in FIG. 3, in some non-limiting embodiments, suspension lines 30 may be connected to roof hoist 10 via winches (not shown) and the like for lifting roof 22 via suspension lines 30. In other non-limiting embodiments, described in greater detail below, suspension lines 30 may be connected directly to roof hoist 10 without the use of winches.
Referring now to FIG. 4, roof hoist 10 lifting roof 22 is depicted according to a non-limiting embodiment. Frame 14 includes a top portion 38 supported by a plurality of legs 42. The distance between at least one pair of neighboring legs 42 is preferably large enough to allow at least that pair of legs 42 to straddle roof 22, facilitating the positioning of roof hoist 10 over roof 22. Hooks 26 are suspended by suspension lines 30 from top portion 38. Legs 42 support top portion 38, and therefore suspension lines 30 and hooks 26, while roof hoist 10 is being positioned over roof 22. The plurality of wheels 18 on each leg 42 allow roof hoist 10 to be moved as a whole in order to position it correctly over roof 22. Hooks 26 extend partially underneath roof 22 to support the weight of roof 22. An overhead lifting mechanism 46, such as the hook of a gantry crane, is coupled to top portion 38 and lifts top portion 38 from legs 42 once hooks 26 have engaged roof 22 and roof 22 is ready for lifting. Once lifted from either the ground or from beams or posts 34, roof 22 may then be deposited on a dwelling, and hooks 26 may be removed. Top portion 38 may then be lowered back onto legs 42 by overhead lifting mechanism 46, in preparation for lifting a further roof 22.
Referring now to FIG. 5, roof hoist 10 is depicted, according to a non-limiting embodiment. Top portion 38 includes a set of three substantially parallel beams 50a, 50b and 50c, generically referred to herein as a beam 50, and collectively, as beams 50. In some embodiments, top portion 38 also includes a set of three transverse beams 54a, 54b and 54c, generically referred to as a transverse beam 54, and collectively, as transverse beams 54. Transverse beams 54 are substantially perpendicular to beams 50. Beams 50 lie substantially in a first plane, and transverse beams 54 lie substantially in a second plane which is parallel to the first plane and at a different elevation than the first plane. In effect, as depicted in FIG. 5, beams 50 are arranged to lie on top of transverse beams 54, although it will be understood that transverse beams 54 could alternatively lie on top of beams 50. In addition, it will be understood that a higher or lower number of beams 50 are also envisioned, in combination with either a higher or lower number of transverse beams 54.
Top portion 38 is supported in some embodiments on legs 42 located near each end of beams 50a and 50c, though it will be noted that top portion 38 may alternatively be supported by legs 42 located near each end of transverse beams 54a and 54c. Additionally, supporting legs 42 may be located at any suitable combination of the ends of beams 50a and 50c and transverse beams 54a and 54c. In the event that varying numbers of beams 50 and transverse beams 54 are used, legs 42 may be located near the ends of any combination of beams 50 and transverse beams 54 which provides suitably stable support for top portion 38.
In some embodiments, overhead lifting mechanism 46 is coupled to beams 50a and 50c of top portion 38, though it will be understood that overhead lifting mechanism 46 may also be coupled to transverse beams 54a and 54c, or to any suitable combination of beams 50 and transverse beams 54.
Where beams 50 and transverse beams 54 intersect near the periphery of top portion 38, for example the intersection between beam 50a and transverse beam 54a, beams 50 and transverse beams 54 are coupled to each other by tension connectors 58 or compression connectors 62. Tension connectors 58 and compression connectors 62 will be described in detail below. Intersections located away from the periphery of top portion 34, such as the intersection between beam 50b and transverse beam 54b, may not require connectors, but it will be understood that tension connectors 58 or compression connectors 62 could nevertheless be applied in other embodiments. In still other embodiments, tension connectors 58 or compression connectors 62 may not be necessary at all peripheral intersections between beams 50 and transverse beams 54. Tension connectors 58 or compression connectors 62 may be applied to any combination of intersections which provides sufficient structural integrity to top portion 38, as will be discussed below.
In some embodiments, as depicted in FIG. 5, tension connectors 58 are used to couple beams 50a and 50c to each of transverse beams 54. Thus, transverse beams 54 are supported via tension connectors 58 by beams 50a and 50c, which are in turn supported by legs 42. Beam 50b is not supported by legs 42 and therefore does not support transverse beams 54. Rather, beam 50b is coupled to transverse beams 54a and 54c by compression connectors 62, and is therefore supported via compression connectors 62 by transverse beams 54a and 54c. It will be noted that additional beams 50 may be added between beams 50a and 50c which may be supported via compression connectors 62 by transverse beams 54. Likewise, additional transverse beams 54 may be added between transverse beams 54a and 54c which may be supported via tension connectors 58 by beams 50a and 50c. As noted above, any combination of beams 50, transverse beams 54, tension connectors 58 and compression connectors 62, which provides support for all beams 50 and transverse beams 54 via legs 42 or via other beams 50 or transverse beams 54, may be used for top portion 38. Additionally, it will be understood that top portion 38 is thus held together by forces of compression and tension, and that no other fastening means are necessary, though fasteners may be used nevertheless.
Hooks 26 are suspended from beams 50 and transverse beams 54 by suspension lines 30. It will be understood that other configurations of hooks 26 hanging from top portion 38 may also be used in addition to the configuration depicted in FIG. 5.
In some embodiments, as depicted in FIG. 5, each leg 42 includes a centre post 66, a substantially horizontal cruciform base 70, and four buttress members 74. An end of centre post 66 is joined to base 70 near the centre of base 70. Centre post 66 therefore extends substantially vertically from base 70. Four buttress members 74 are connected to base 70 and centre post 66. Each buttress member 74 extends from an extremity of base 70 to a point along the length of centre post 66. Four wheels 18 are disposed on the underside of base 70, with one wheel 18 being located on each extremity of base 70. Wheels 18 may be swivelably mounted on base 70, allowing leg 42 to be rolled in any direction. It will be understood that in other embodiments, the number of buttress members 74 may be varied, or buttress members 74 may be omitted altogether in further embodiments. Similarly, the dimensions of centre post 66 may be varied, and centre post 66 may also be replaced with a plurality of posts, which may be coupled to each other by base 70 or other connecting means, such as struts. Base 70 may therefore be omitted entirely if centre post 66 or multiple posts provide sufficient surface area to allow for the mounting of wheels 18. Varying numbers of wheels 18 are also contemplated, insofar as wheels 18 provide a stable base of support for each leg 42.
Referring now to FIGS. 6 and 7, the connection between a portion of beam 50a and leg 42 is described. It will be understood that similar connections between legs 42 and other portions of beam 50a or other beams 50 or transverse beams 54, are also contemplated. An end of beam 50a is depicted in FIG. 6. Beam 50a, and likewise beams 50 and transverse beams 54, may have a truss structure as depicted in FIG. 6, or any other suitable load-bearing structure, such as a hollow structure of various cross sectional shapes, or a solid structure of various cross sectional shapes, for example an I-shaped structure. In any event, an upper end of leg 42, depicted in FIG. 7, bears a cradle 78 and beam 50a is received in cradle 78. In some embodiments, cradle 78 may have a U-shaped structure, but in other embodiments cradle 78 may also have any suitable structure for receiving a portion of beam 50a, such as a V-shaped structure or a semi-circular structure. Cradle 78 receives a portion of beam 50a and beam 50a may be fixed to cradle 78 by a pair of bands 82. Bands 82 may be nylon ratchet bands which engage holes (not shown) in cradle 78 via a hook (not shown) at each end of each band 82. Beam 50a is thus prevented from moving relative to leg 42. It will be understood that bands 82 may also be other means suitable for fastening beam 50a to cradle 78, such as U-bolts, rope and the like. Further, in some embodiments where beam 50a has a truss structure, bands 82 may be replaced by struts (not shown) extending through beam 50a from one side of cradle 78 to another.
Hook 26 is depicted in FIGS. 8 and 9, and includes a roof support member 86, and a stem 90 which lies in substantially the same plane as roof support member 86. Stem 90 has a joining section 94 and an inclined section 98. Joining section 94 extends substantially perpendicularly from an end of roof support member 86. For the description which follows, positions will be defined in relation to the connection between roof support member 86 and joining section 94. Where applicable, positions closer to the connection between roof support member 86 and joining section 94 will be referred to as proximal. Positions further from the connection between roof support member 86 and joining section 94 will be referred to as distal.
Inclined section 98 extends from the distal end of joining section 94 and includes a loop 102 near the distal end of inclined section 98. Loop 102 may be any suitable connecting structure for receiving a suspension line 30. Inclined section 98 is angled in relation to joining section 94 in order to extend over roof support member 86. In some embodiments, as depicted in FIG. 9, loop 102 may be substantially in vertical alignment with the distal end of roof support member 86. The weight of a portion of roof 22 will be transmitted to loop 102 from the distal end of roof support member 86 via roof support member 86 and stem 90. Therefore, the vertical alignment of loop 102 with the distal end of roof support member 86 prevents the generation of a moment of force on hook 26, which could result in an undesired rotational movement of hook 26 about loop 102.
Hook 26 also includes a roof contact member 106 located near the distal end of roof support member 86. In some embodiments, as depicted in FIGS. 8 and 9, roof contact member 106 may be an elongated L-shaped bar, having a substantially horizontal section 106a, and a substantially vertical section 106b extending from the distal edge of the horizontal section. A portion of horizontal section 106a may be connected to the upper surface 110 of roof support member 86. The connection between horizontal section 106a and upper surface 110 may be located near the middle of horizontal section 106a, such that roof contact member 106 is substantially symmetrical on either side of roof support member 86. It will be understood that other structures are possible for roof contact member 106. For example, horizontal section 106a may be omitted in other embodiments, and vertical section 106b may simply be connected to the distal face 114, depicted in FIG. 8, of roof support member 86.
In some embodiments, as depicted in FIGS. 8 and 9, roof contact member 106 may include at least one substantially downwardly extending protrusion, for example a pair of posts 118. Posts 118 are disposed near the ends of roof contact member 106, and provide a wider base of support for hook 26. Posts 118 thus allow hook 26 to be placed on the ground underneath a portion of roof 22 without falling or shifting positions. Posts 118 may extend downwardly beyond the underside of roof support member 86 in some embodiments. A foot 122, depicted in FIG. 8, may therefore be provided extending downwardly from the underside of the proximal end of roof support member 86. The bottom surfaces of posts 118 and foot 122 lie in substantially the same plane, providing a stable, substantially horizontal base of support for hook 26. Alternatively, as depicted in FIG. 9, foot 122 may be omitted, causing hook 26 to rest on the ground at a slight incline. In still further embodiments (not shown), foot 122 may be omitted and the length of posts 118 or the thickness or angle of roof support member 86 may be altered in such a way that the bottom ends of posts 118 line up substantially horizontally with the underside of the proximal end of roof support member 86.
In some embodiments, as depicted in FIG. 8, vertical section 106b of roof contact member 106 includes three lips 126 extending towards stem 90 from the upper edge of vertical section 106b. Lips 126 are disposed substantially symmetrically along the length of vertical section 106b. It will be understood, however, that other embodiments may have more or less than three lips 126 extending along varying portions of the length of vertical section 106b, and that lips 126 need not be symmetrically arranged. Lips 126 contact a structural member 130 of roof 22, as depicted in FIG. 9, thus transferring a portion of the weight of roof 22 to roof support member 86, through stem 90 and to roof hoist 10 via suspending line 30. Additionally, a plurality of lag screws (not shown) may extend through a plurality of openings 128 in lips 126 to engage structural member 130 and prevent structural member 130 from shifting on vertical section 106b. In further embodiments, lips 126 may be omitted and structural member 130 may simply rest on the upper edge of vertical section 106b.
Referring now to FIGS. 10 and 11, tension connector 58 of the roof hoist 10 is depicted according to a non-limiting embodiment. Tension connector 58 includes two wheel assemblies 134a and 134b, referred to generically as wheel assembly 134 and collectively as wheel assemblies 134. Wheel assembly 134a includes four wheels 138a, 138b, 138c and 138d, referred to generically as wheel 138, and collectively as wheels 138. Wheels 138a and 138b are substantially coaxial, as are wheels 138c and 138d. Additionally, wheels 138a and 138c are substantially parallel, as are wheels 138b and 138d. A pair of tracks 142 extend from wheel assembly 134a, with one track 142 lying in substantially the same plane as the outside surfaces 146 of wheels 138a and 138c, and the other track 142 lying in substantially the same plane as the outside surfaces (not shown) of wheels 138b and 138d. Tracks 142 define a channel into which a portion of beam 50 is received. In addition, the alignment of wheels 138 as described above defines two lines of contact along a surface of the received beam 50. Wheel assembly 134a is therefore configured to roll along the length of beam 50, while tracks 142 prevent undesired width-wise motion of wheel assembly 134a on beam 50.
In some embodiments, as depicted in FIGS. 10 and 11, wheel assembly 134b is substantially identical to wheel assembly 134a. Wheel assembly 134b includes four wheels 138 having a substantially identical configuration to wheels 138a, 138b, 138c and 138d as described with reference to wheel assembly 134a. Wheel assembly 134b, however, is inverted and rotated by approximately 90° in relation to wheel assembly 134a. In other non-limiting embodiments, wheel assembly 134b may be rotated by an angle other than approximately 90° relative to wheel assembly 134a. A portion of transverse beam 54 is received within the channel defined by tracks 142 of wheel assembly 134b, and wheels 138 of wheel assembly 134b allow wheel assembly 134b to roll along the length of beam 54.
Wheel assemblies 134 are substantially in vertical alignment, as depicted in FIGS. 10 and 11, and are coupled to each other by a plurality of posts 150. Posts 150 are sufficiently distanced to allow beam 50 and transverse beam 54 to pass therebetween. The configuration of wheel assemblies 134 within tension connector 58 allows tension connector 58 to receive both beam 50 and transverse beam 54 between wheel assemblies 134. Tension connector 58 thus creates an intersection between beam 50 and transverse beam 54, in which beam 50 and transverse beam 54 are coupled substantially perpendicularly to each other. In other non-limiting embodiments, beam 50 and transverse beam 54 may be coupled in non-perpendicular orientations. Wheel assembly 134a rests on the upper surface of beam 50, while wheel assembly 134b is suspended from wheel assembly 134a and contacts the lower surface of transverse beam 54. As was previously discussed with reference to FIG. 5, transverse beam 54 is supported by beam 50 via tension connector 58. The intersection between beam 50 and transverse beam 54 may be moved along the length of beam 50 or transverse beam 54 by rolling wheel assemblies 134 along beam 50 or transverse beam 54. It will be noted that in other embodiments, variations upon the above-described structure of tension connector 58 may be used. For example, various numbers of wheels 138 may be used in wheel assemblies 134. Wheel assemblies 134 may be coupled to each other using various numbers of posts 150, or posts 150 may be replaced by other connecting means suitable for tension loading such as cables or ropes. As was discussed with reference to FIG. 5, transverse beam 54 need not be supported by beam 50. Rather, beam 50 may be supported by transverse beam 54 in an alternative configuration of top portion 38.
Compression connector 62 according to a non-limiting embodiment is depicted in FIGS. 12 and 13. Compression connector 62, like tension connector 58, includes two wheel assemblies 134a and 134b having the configurations as described above with reference to FIGS. 10 and 11. Each wheel assembly 134 of compression connector 62 therefore includes four wheels 138, which are configured as described with reference to FIGS. 10 and 11. Further, each wheel assembly 134 also includes a pair of tracks 142 which provide channels able to receive portions of beam 50 or transverse beam 54. Wheel assembly 134b of compression connector 62 is substantially identical to wheel assembly 134a of compression connector 62, and is inverted and rotated by approximately 90° as depicted in FIGS. 12 and 13. Angles of rotation other than 90° may also be used in other non-limiting embodiments. Wheel assemblies 134 are in substantially vertical alignment, and may be substantially adjacent to each other in some embodiments, as depicted in FIGS. 12 and 13. It will be understood, however, that wheel assemblies 134 may also be separated by varying distances. Wheel assemblies 134 may be coupled to each other by one or more plates 154 in some embodiments. Wheel assembly 134a receives between tracks 142 a portion of the underside of beam 50, while wheel assembly 134b receives between tracks 142 a portion of the upper side of transverse beam 54. A cover 158 may be coupled to wheel assembly 134a by connectors 162 in order to prevent beam 50 from lifting away from wheel assembly 134a. Wheel assemblies 134 are thus located adjacent to each other and in between beam 50 and transverse beam 54. Transverse beam 54 is thus supporting beam 50 via compression connector 62 at a moveable intersection, for example the intersection between beam 50b and transverse beam 54a as depicted earlier in FIG. 5. Beam 50 and transverse beam 54 are coupled substantially perpendicularly to each other at the intersection, although it will be appreciated that non-perpendicular orientations may be used in other non-limiting embodiments. A cover may be coupled to wheel assembly 134a by connectors 162 in order to prevent beam 50 from lifting away from wheel assembly 134a. As with tension connector 58, it will be understood that transverse beam 54 may alternatively be supported by beam 50. Additionally, wheel assemblies 134 may include higher or lower numbers of wheels 138 in any suitable arrangement which facilitates the movement of wheel assemblies 134 along the length of beam 50 or transverse beam 54.
Referring back to FIGS. 1 and 2, in operation, roof hoist 10 is positioned over a roof 22. Roof 22 may be substantially completed—including heating, ventilation and air conditioning (HVAC), electrical and mechanical installations—or may be at any other desired stage of construction. Once roof hoist 10 is positioned over roof 22, hooks 26 suspended from beams 50 and transverse beams 54 by suspension lines 30, are engaged with roof 22 by sliding roof support members 86 underneath portions of roof 22, as depicted in FIG. 2. Roof contact members 106 may also be engaged with structural members 130 of roof 22, as depicted in FIG. 9. With hooks 26 arranged at the perimeter of roof 22 and extending under roof 22, roof 22 may be lifted by shortening suspension lines 30, as depicted in FIG. 3. Alternatively, bands 82 depicted in FIG. 7 may be removed to decouple beams 50 from legs 42. Overhead lifting mechanism 46 may then be used to lift top portion 38, and roof 22 with it, from legs 42, as depicted in FIG. 4. Roof 22 may then be maneuvered by overhead lifting mechanism 46 to position roof 22 over a dwelling which has reached a desired stage of construction. Roof 22 may be lowered onto the dwelling, and hooks 26 may be removed. Overhead lifting mechanism 46 may then deposit top portion 38 back onto legs 42, where bands 82 may be used to couple top portion 38 with legs 42. Roof hoist 10 is then ready to be positioned over a further roof 22.
Persons skilled in the art will appreciate that there are yet more alternative implementations and modifications possible for implementing the embodiments, and that the above implementations and examples are only illustrations of one or more embodiments. The scope, therefore, is only to be limited by the claims appended hereto.
