Patent Publication Number: US-2022220741-A1

Title: Davit Arm Base

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a national phase entry under 35 U.S.C. § 371 of International Patent Application PCT/AU2020/000033, filed Apr. 16, 2020, designating the U.S. of America and published in English as International Patent Publication WO 2020/210858 on Oct. 22, 2020, which claims the benefit under Article 8 of the Patent Cooperation Treaty to Australian Patent Application Serial No. 2019901320, filed Apr. 16, 2019, the entireties of which are hereby incorporated by reference. 
    
    
     FIELD OF INVENTION 
     This invention relates to a davit arm base. More particularly, this invention relates to a davit arm base for buildings. Still more particularly, this invention relates to a davit arm base for a davit arm for suspending a load from the side of a building. 
     BACKGROUND ART 
     The following references to and descriptions of prior proposals or products are not intended to be, and are not to be construed as, statements or admissions of common general knowledge in the art. In particular, the following prior art discussion should not be assumed to relate to what is commonly or well known by the person skilled in the art, but to assist in the inventive process undertaken by the inventor(s) and in the understanding of the invention. 
     Davits for buildings includes structural arms designed to suspend items over a structure&#39;s edge, for example over a ledge, wall, railing, balustrade, etc. The structure may be a building, ship, or other structure having a sheer vertical wall or structural features aligned in a vertical plane along which the item may be positioned. Davit arms may be used to suspend a window cleaner from the side of the building, with the cantilevered davit arm extending horizontally from a post and clearing a non-structural building feature, such as a balustrade. The davit arm may be removable. It may be temporarily fitted to the building via a socket that is fixed to the building. 
     Davit bases may be installed in open terraces and balconies. In such cases, it would be advantageous to ensure that the socket is recessed into the floor surface or slab at least to a level where its upper portions are flush with the floor surface and no portions protrude there above. 
     Recessing a base in a slab surface may need to be done when balcony concrete is poured. Otherwise, the floor material must be cored out to allow the base to be installed. Coring out a floor surface may be costly and may not be straightforward, particularly where the floor is made of concrete. 
     An object of the present invention is to ameliorate one or more of the aforementioned disadvantages of the prior art or to at least provide a useful alternative thereto. 
     STATEMENT OF INVENTION 
     The invention according to one or more aspects may be as defined in the independent claims. Some optional and/or preferred features of the invention are defined in the dependent claims. 
     Accordingly, in one aspect of the invention there is provided: 
     A davit arm holder for a davit arm for suspending lines from elevated heights by mounting the davit arm on a structural substrate, said davit arm holder comprising a base formed from one or more planar layers of sheet material adapted to lie parallel to the plane of a surface of the substrate material, and an attachment adapted to be fixedly attached to the base and to provide a connection to engage a davit arm, 
     wherein: 
     A. the base comprises:
         a. an outer layer having a plurality of first engagement portions that are radially spaced from a centre point of the base; and   b. at least one inner mount integrally formed with the outer layer, fixedly securable to the substrate and adapted to space an inside surface of the outer layer from the substrate to form a gap under the outer layer, whereby the base is adapted to have a low-profile when anchored to the substrate,       

     B. the attachment is adapted to be releasably engaged to the base by a plurality of second engagement portions adapted to engage the corresponding plurality of first engagement portions by rotation of the attachment about an axis perpendicular to the plane. 
     Substrate 
     The structural substrate may be a structure presenting a substantially planar surface, such as a concrete slab, metal or wooden panel or proximal studs and the like. The substrate may be a wall or may have a horizontal surface or a surface inclined to the horizontal. The substrate may be a column or post. Preferably, the substrate is a floor. Preferably, the substrate comprises a concrete slab, which may be tiled or otherwise have a surface covering. Preferably, the substrate forms part of a roof, balcony, veranda or terrace of an elevated structure. 
     Base 
     The base is preferably fixed to the substrate. The low profile therefore enables the substrate to be used for other purposes when the davit arm is not installed without material interference of the base. 
     The outer layer may comprise a planar plate. The plate may be formed from a thick sheet of metal material, such as 6 mm steel plate. The outer layer may have a thickness extending the width of the sheet material. 
     The size of the gap may be defined by the thickness of the inner mount. The inner mount may be formed from the same sheet of material as the outer layer. The inner mount may be formed from a separate material to the outer layer. Preferably, the outer layer is welded or otherwise integrally formed with the inner mount. 
     The first engagement portions may be aligned tangentially in line with a nominal circle that is concentric with the centre point. The first engagement portions may be in the form of tangentially aligned slots. The slots may have inner side walls that follow an inner curve that has a general radius less than the nominal circle. The slots may have outer side walls that follow an outer curve that has a general radius greater than the nominal circle. 
     Attachment 
     The attachment has a connection that is adapted to releasably engage a davit arm. The connection may be in the form of a recess, channel or other female structure adapted to receive an end of a davit arm for engagement. The connection may comprise a socket. The socket may define a square or cylindrical recess. Preferably, the socket defines a cylindrical recess suitable to receive a cylindrical end of a davit arm. The davit arm may include a cylindrical sock that corresponds to the recess. 
     The attachment is not unintentionally removable from the base. A pin and aperture combination may be used to prevent inadvertent rotation of the attachment relative to the base. 
     The attachment is rotatable about the axis perpendicular to the plane of the substrate. Preferably, the rotation is about an axis coaxial with the centre point. 
     The second engagement portions may be in the form of protrusions. The protrusions may be in the form of toes or feet. The protrusions may have a footprint wider than the slots. The protrusions may have a footprint wider in a radial line from the centre point than the slots. Therefore, the protrusions may be adapted on engagement with the first engagement portions to be trapped under the outer layer in the gap. 
     Davit Arm 
     The davit arm comprises a lateral arm. If the base were to be wall mounted, the lateral arm may be received directly into the socket recess. The davit arm normally comprises a post and the lateral arm. the post is normally upright. The post may be adapted to be oriented substantially vertically. The lateral arm may extend substantially horizontally. 
     The lines may be suspended from a free and cantilevered end of the davit arm. The ines may be used to suspend workers at heights, such as window cleaners and other maintenance and repair workers working at heights on the sides of multiple story buildings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention may be better understood from the following non-limiting description of preferred embodiments, in which: 
         FIG. 1  is a perspective view of a davit arm mounted in a davit arm holder in accordance with an embodiment the invention; 
         FIG. 2  is a perspective view of a davit arm holder in accordance with the embodiment shown in  FIG. 1 ; 
         FIG. 3  is an exploded perspective view of a davit arm and davit arm holder in accordance with the embodiment shown in  FIG. 1 ; 
         FIG. 4  is an exploded perspective view of a davit arm holder in accordance with the embodiment shown in  FIG. 1 ; 
         FIGS. 5 a  and 5 b    are top views of a davit arm holder in accordance with the embodiment shown in  FIG. 1  in unengaged and engaged portions, respectively; and 
         FIG. 6  is an underside perspective view of a first engagement portion engaged to a second engagement portion in accordance with the embodiment shown in  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     Preferred features of the present invention will now be described with particular reference to the accompanying drawings. However, it is to be understood that the features illustrated in and described with reference to the drawings are not to be construed as limiting on the scope of the invention. 
     Referring to the drawings, there is shown a davit arm holder  30 , 50  for a davit arm  10  for suspending lines  4  from elevated heights by mounting the davit arm  10  on a structural substrate  1 , said davit arm holder  30 , 50  comprising a base  50  formed from one or more planar layers of sheet material including a base plate  52 , the planar layers adapted to lie parallel to a general plane P of a surface of the substrate  1 , and an attachment  30  adapted to be fixedly attached to the base  50  and to provide a connection in the form of a cylindrical socket  32  to engage a davit arm  11 - 18 . The base  50  includes an outer layer in the form of the base plate  52  and at least one inner mount in the form of a mounting flange  60 . The inner mount is relationally inward relative to the innermost feature being the substrate  1 , with the outer layer  52  further spaced away from the substrate  1 . 
     The outer layer comprising the base plate  52  has a plurality of first engagement portions in the form of slots  70  that are radially spaced from a central region having a centre point  54  of the base  50 . The slots are generally tangentially aligned on the periphery of, and are circumferentially spaced about, the base  50 . The slots  70  all face in the same clockwise or anticlockwise direction and comprise a radially outer arm  70   a  that defines one inside face of an outer wall  70   b  of each slot  70 . An inner wall  72  of each slot  70  is formed by the periphery of the base plate  52 . The outer arm  70   a  terminates at an end  70   c  corresponding to a mouth of the slot  70  and in plan, overhangs radially inwardly in short cantilever manner over the outer wall inside surface  70   b.    
     The at least one inner mounting flange  60  is integrally formed with the outer layer comprising the base plate  52 . The flange  60  is fixedly securable to the substrate  1  and is adapted to space an inside or underside surface  68  of the base plate  52  from the substrate  1  to form a vertical gap  66  under the outer layer  52 . The base  50  is adapted to have a low-profile when anchored to the substrate  1 . The attachment  30  is adapted to be releasably engaged to the base  50  by a plurality of second engagement portions each including an outlying socket plate flange  38 , a socket toe  40  and a smaller bridging portion  42 . The socket toe  40  is a small flat plate having a footprint substantially corresponding to that of the corresponding socket plate flange  38 . The bridging portion  42  is adapted to slide into a corresponding one of the slots  70 . The second engagement portions  39 , 40 , 42  are adapted to engage the corresponding plurality of first engagement portions  70  by rotation of the attachment  30  about an axis  56  perpendicular to the plane of the substrate  1 . 
     The attachment may be in the form of a removable socket  30 . The base  50  advantageously has a low profile comprising the height of the mounting flange  60  (defining the vertical gap  66 ) and the thickness of the base plate  52 . The base  50  is affixed to the building structure or substrate  1  by fasteners  62  such as bolts extending through apertures  64 . The base  50  may have a substantially cross (x) shape in plan view, namely having a broad central disc in the form of the plate  52  and two pairs of diagonally opposed and circumferentially equi-spaced mounting flanges  60  extending beyond the general peripheral edge  75  of the central disc of the base plate  52 . Similarly, in plan view, the attachment  30  is cruciform shaped and has a general central disc in the form of the socket plate  36  and two pairs of diagonally opposed socket plate flanges  38  extending beyond the general outer periphery  36   a  of the socket plate  36 . 
     The upper removable socket  30  is adapted to engage the low profile base  50 . A rotational movement in the clockwise direction R is required to lock the top socket attachment  30  to the base  50 , whereby the socket toe  40  is adapted to slide passed the radially inner side  61  of the corresponding mounting flange  60 , as the bridging portion  42  enters the corresponding slot  70  and an underside peripheral surface  31  of a socket plate  41  slides over the inner wall  72  and the radially outer arms  70   a  of the slots  70 . The underside peripheral surface  31  corresponds to the socket plate flange  38  and in plan is super-imposed over the sock toe  40 . 
     The socket toe  40  is, in plan view, generally trapezoidal and slightly wedge shaped, with its leading end having a narrower head portion  46  than the opposite tail-end thereof. The head portion  43  has rounded corners to facilitate entry of the socket toe  40  passed the leading corner of the outer wall inside face  70   b.    
     The base  50  is of a height and geometry that allows it to sit under and between most commercial paver systems used on terrace substrates  2  of high rise buildings. 
     As shown in  FIG. 4 , the attachment  30  is placed over the base  50  so that the socket plate  36  is superimposed over the base plate  52  and parallel-planar thereto. The socket toes  40  are respectively positioned anti-clockwise of the corresponding mounting flange  60  as shown in  FIG. 5 a   , and the attachment  30  is then rotated clockwise in direction R to engage the socket toes  40  in the grooves or slots  70  as shown in  FIG. 5 b   . Each toe  40  has a corresponding slot  70  adapted to receive the bridging portion  42  of the toe  40 . 
     A view from underneath the base  50  is shown in  FIG. 6 . The toe  40  is engaged to secure the assembly  30 , 50  together. 
     A pin  49  (including a cotter pin) or similar, is used to secure the two parts, the attachment  30  and the base  50 , from unintentionally rotating in a reverse direction to R and disengaging. 
     The removable socket attachment  30 , when secured to the base  50 , is shown in  FIG. 3 . 
     The davit arm assembly  10  is then installed into a recess  34  defined by a cylinder  32  of the attachment  30 . 
     In terms of advantages, the preferred embodiment provides that:
         The base (in terms of manufacturing and supply to market, the high volume part) is greatly simplified, being constructed of only a flat plate  52  integrally formed with flat mounting flanges  60 .   The base  50  may be easily affixed with bolt  62  style fittings. This eliminates the prior art need to completely recess a socket into a slab substrate  1  by excavation of the concrete.   The cross (x) configuration of the base  50  allows it to sit neatly under or in between pod or paver  2  systems.   The rotational lock mechanism  40 , 70  allows for a compact and low-profile system of attachment, allowing the base  50  to be fitted by lifting one paver or tile  2  of the substrate  1  only.   The rotational locking arrangement between protrusions  40  and recesses  70  offers a highly secure load transfer between the socket attachment  30  and the base  50 .       

     Turning in more detail to the drawings,  FIG. 1  shows the davit arm  10  arrangement of one embodiment in its entirety. The davit arm  10  comprises a substantially vertical post  12  made from square section tubing that has a partial cylindrical sleeve  11  adapted to be received in the corresponding cylindrical recess  34  so that the lateral arm  16  may be permitted to swivel through a limited arc defined by a detent in the cylinder  32  that coacts with the gap  13  between the side edges  15  of the partial cylindrical sleeve  11 . The upper end of the post  12  is fitted with an elbow  14  enabling the lateral arm  16  to be fitted thereto. The lateral arm  16  comprises a leading cantilevered end with the telescoping extension  18  to which the lines may be attached and its mounted end includes a detent  17 . Accordingly, the lateral arm  16  may be fed through a through hole in the elbow  4  and trapped in place by the detent  17  as shown in  FIG. 2 . 
     The base  50  is shown in  FIGS. 4-6  to comprise an outer layer in the form of the base plate  52  that is cut or cast to define a series of tangentially aligned peripheral slots  70  arranged to be radially spaced from the centre point  54  and circumferentially spaced around a nominal circle  51 . 
     The slots  70  may number  2 - 4  or more. Four slots  70  are preferred and this enables the plan or footprint of the base  50  to be generally cross shaped and to sit neatly in a square shaped cavity  3  that may be vacated by removing a paver or tile  2  preparatory to installation of the base  50 . 
     The inside wall  44  of the toe  40  may have a substantially identical radius compared to the outer toe wall  48 , or may be marginally smaller. Alternatively, where the slot is short in length (for example, about as long as it is wide), the inside and outer walls  44 , 48  may define a linear slot and be substantially parallel. 
     The gap  66  may be defined by the height of the inner mounting flanges  60 . These are “inner” in the sense that they are closest to the substrate  1  and the plate  52  thereby represents an outer layer of the base  50 . 
     The mouths of the slots  70  face anticlockwise toward an approaching leading toe edge  46  in the engagement process. Each toe  40  depends from the underside  68  of the plate  52  by a bridge  42 , being a thin portion connecting the toe  40  to the plate  52  and being dimensioned to slide into and be retained in the slot  70 . The toe  70  has a wider lateral or radial (relative to the axis  54 ) footprint than the width of the slot  70  so that engagement of the toe  40  in the slot traps the foot against axial displacement relative to the plate  52 . 
     The inner mounting flanges  60  may be welded to the periphery of the underside  68  of the plate  52  and present apertures  64  for reception of bolts  62  to enable the base  50  to be anchored permanently to a substrate  1  by engaging corresponding apertures formed in the substrate  1 . Multiple apertures  64  are provided and not all will be used to engage with the substrate depending on the expected load on the davit arm  10 . 
     Lateral diagonally and radially extending brace arms  31  strengthen the structure of the attachment  30  with regard to the join  35  between the cylindrical socket  32  an the socket plate  36  as the momentary forces applied by the davit arm  10  at the join  35  can be significant. Diametrically opposed brace arms  37  are unitarily formed with a pair of handles  33  that assist in manipulation to engage or disengage the attachment  30  from the base  50 . The base of the brace arms  31 , 37  is fixed to radial flange extensions  38  of the socket plate  36  that, in plan, are superimposed over the respective toes  40 . As seen in  FIG. 6 , the radially inner side  61  of the mounting flange  60  defines an end wall at the clockwise end beyond the closed end of the slot  70  to limit extent of translation of the toe  40  and the clockwise rotation of the attachment  30  relative to the base  50 . 
     Welded blocks  39  located on the peripheral flange extensions  38  either side of each base of each brace arm  31 , 37  further stabilise the structure. 
     The base  50  achieves a low profile, being formed of one outer layer  52  in turn formed from a sheet of metal material (eg. 3-4 mm thick), and the inner mounting flange  60  layer formed of a thicker plate material (eg. 5-6 mm thick), so that the entire height of the base  50  comprises in effect only two layers of sheet material. 
     
       
         
           
               
               
               
               
             
               
                   
               
               
                 Ref 
                 Description 
                 Ref 
                 Description 
               
               
                   
               
             
            
               
                  1 
                 substrate 
                 30 
                 davit arm attachment 
               
               
                  2 
                 paver or tile 
                 31 
                 reinforcing brace arm 
               
               
                  3 
                 cavity 
                 32 
                 socket cylinder 
               
               
                  4 
                 lines 
                 33 
                 handle 
               
               
                 10 
                 davit arm 
                 34 
                 recess 
               
               
                 11 
                 partial cylindrical 
                 35 
                 join between cylinder 
               
               
                   
                 sleeve 
                   
                 and socket plate 
               
               
                 12 
                 davit post 
                 36 
                 socket plate 
               
               
                 13 
                 gap 
                  36a 
                 outer periphery of 
               
               
                   
                   
                   
                 socket plate 
               
               
                 14 
                 davit elbow 
                 37 
                 brace arm with handle 
               
               
                 15 
                 side edges 
                 38 
                 socket plate flange 
               
               
                 16 
                 lateral arm 
                 39 
                 reinforcing blocks 
               
               
                 17 
                 detent 
                 40 
                 socket toe 
               
               
                 18 
                 telescopic extension 
                 41 
                 underside peripheral 
               
               
                   
                 to davit arm 
                   
                 surface of socket plate 36 
               
               
                 50 
                 base 
                 42 
                 toe bridge 
               
               
                 51 
                 nominal circle 
                 44 
                 inside wall of toe 
               
               
                 52 
                 base plate 
                 46 
                 leading edge of toe 
               
               
                 54 
                 centre point 
                 48 
                 outer wall of toe 
               
               
                 56 
                 rotational axis 
                 49 
                 pin including cotter pin 
               
               
                 61 
                 radially inner side 
               
               
                   
                 of mounting flange 
               
               
                 70 
                 first engagement slots 
                 60 
                 inner mounting flange 
               
               
                  70a 
                 outer arm 
                 62 
                 fasteners 
               
               
                  70b 
                 outer wall inside surface 
                 64 
                 apertures 
               
               
                  70c 
                 terminal end of outer arm 
                 66 
                 gap 
               
               
                 72 
                 inner wall of slots 
                 68 
                 underside surface of base 
               
               
                   
                   
                   
                 plate 
               
               
                 74 
                 outer wall of slots 
                 R 
                 direction of rotation to engage 
               
               
                   
                   
                   
                 attachment 30 to base 50 
               
               
                 75 
                 peripheral edge of base 
                 P 
                 Plane of substrate surface 
               
               
                   
                 plate 
               
               
                   
               
            
           
         
       
     
     Throughout the specification and claims the word “comprise” and its derivatives are intended to have an inclusive rather than exclusive meaning unless the contrary is expressly stated or the context requires otherwise. That is, the word “comprise” and its derivatives will be taken to indicate the inclusion of not only the listed components, steps or features that it directly references, but also other components, steps or features not specifically listed, unless the contrary is expressly stated or the context requires otherwise. 
     In the present specification, terms such as “apparatus”, “means”, “device” and “member” may refer to singular or plural items and are terms intended to refer to a set of properties, functions or characteristics performed by one or more items or components having one or more parts. It is envisaged that where an “apparatus”, “means”, “device” or “member” or similar term is described as being a unitary object, then a functionally equivalent object having multiple components is considered to fall within the scope of the term, and similarly, where an “apparatus”, “assembly”, “means”, “device” or “member” is described as having multiple components, a functionally equivalent but unitary object is also considered to fall within the scope of the term, unless the contrary is expressly stated or the context requires otherwise. 
     Orientational terms used in the specification and claims such as vertical, horizontal, top, bottom, upper and lower are to be interpreted as relational and are based on the premise that the component, item, article, apparatus, device or instrument will usually be considered in a particular orientation, typically with the lateral arm uppermost. In describing the mounting flanges  60  as “inner” and the base plate  52  as an “outer” layer, this is in relation to the substrate  1  being the innermost feature, with the davit arm  10  extending outwardly therefrom. Thus, where the base  50  is mounted to a horizontal substrate  1 , the inner mount  60  may be a lower mount, and the outer layer  50  may be an upper layer. Although the rotation and orientation of the attachment  30  relative to the base  50  has been described with reference to the terms clockwise and anti-clockwise, the skilled reader with understand that the orientation or directions may be complementarily reversed to a functionally equivalent mirror image arrangement. 
     It will be appreciated by those skilled in the art that many modifications and variations may be made to the methods of the invention described herein without departing from the spirit and scope of the invention.