Patent Description:
The present invention relates to a connection system for use in connecting prefabricated building modules together and to a module support component having connection node assembly components formed therein.

Many high-rise buildings are constructed using pre-fabricated modules that are stacked and joined together on-site. Each module is a generally box shaped unit with a primary chassis comprising vertical support posts and horizontal cross members joined together at corner nodes. Typically, the vertical supports in a module are hollow support structure (HSS), such as steel profiles with a square or rectangular cross-section. A prefabricated module may also be at least partially finished with internal walls, flooring, and hookups for electricity and water.

During construction, an initial tier of modules is installed horizontally and affixed to a building foundation or previously installed substructure. Adjacent top corners of the modules are connected together with a joining plate. A second tier of modules is positioned over the first tier, aligned and positioned in place. The bottom corners of the second tier modules are then affixed to the top corners of the first tier modules.

An advantage of using prefabricated modules is that they can be assembled inside and remotely from the construction site, reducing the amount of outdoor work that must be done at the construction site itself. Notwithstanding, job-site construction often continues in a wide variety of weather conditions. To prevent water from getting into the module assembly and damaging pre-installed components, the module, as supplied, can have an outer weatherproofing layer.

Care must be taken during construction to avoid damaging the weatherproofing layer.

Typically, volumetric modular buildings rely on a separate structure to provide lateral stability against horizontal loads (such as a concrete core or an external steel brace-frame). Each module is only responsible for carrying vertical loads to the tiers below through its vertical columns. Standard methods and systems for connecting prefab building modules during erection are designed to ensure vertical continuity between stacked columns and horizontal continuity between modules of the same level. Continuity is typically achieved by means of large joining plates to connect the corners of adjacent modules. These plates extend well past the vertical support members and are affixed to structures on the horizontal support beams where the connection points are accessible by the installers.

Such use of large joining plates that extend past the vertical support members may require the weatherproofing layer to be peeled back around the corners of the module in order to expose the horizontal support beams to which the plate is connected. However, doing this also exposes a relatively large area of the module itself around the corner and can damage the weatherproofing layer. As a result, there is an increased chance of water gaining entry to the interior of the module during construction and causing damage to interior components.

Further, conventional joining systems often require construction personnel to be positioned at the base of the module when connecting it to a module below. Limited visual and physical access to the corner connections from this position can make proper alignment difficult to achieve. Due to factors such as this, deficiencies in installation control, as well as fabrication tolerances, the installation tolerance in volumetric modular construction is normally in the <NUM> inch to one inch range and modules often need to be manually jacked into their proper alignment after they have been installed. Such misalignments exceed by far the installation tolerances for standard building facade systems which are applied to the outer walls of the building. As a result, much if not all of the facade installation operations need to be done site and this can introduce conspicuous delays to the stacking schedule.

<CIT> discloses a connection system wherein two superimposed hollow bodies are connected by a bolt housed in a conical seat at a bottom end of the upper hollow body and threadedly engaging a bore in a conical guiding pin provided at an upper end of the lower hollow body.

There is a need for an improved method and system for connecting building modules during construction that provides greater accuracy and superior load distribution characteristics along the vertical supports while providing a simplified and safer installation process that can be employed without having to disturb weatherproofing on the module.

These and other needs are met by a connection node system as claimed in claim <NUM>.

The connection node system is largely integrated within the vertical supports that are used in chassis of a modular building unit. Each respective vertical support has a hollow elongated body that extends along a central axis. A first connection portion is formed at the bottom of each support and will be the top portion of the connection node system when that support is mounted on top of a lower support. The first connection portion has an axial bore through it opening into the interior of the support. The axial bore is configured so that a connecting bolt can be passed down through the interior of the support and seat on a shoulder within the bore with the bolt's shank extending out from the support.

A second connection portion is formed on the top of each support and will be the bottom portion of the connection node system when that support is mounted beneath an upper support. The second connection portion comprises an axial hole extending to the interior of the support. The axial hole has a diameter throughout greater than the head diameter of the connecting bolts to permit a bolt and associated drive socket to be fed through the second connection portion and through the support's interior allowing the bolt to engage the bore in the first connection portion. The axial hole should also be large enough to allow a tool for tightening the bolt to be passed through. The axial hole has an internally facing shoulder and is configured so a coupler nut in an insertion position can be placed into the axial hole along the axis and then rotated axially to a captured position where the shoulder blocks axial motion of the coupler towards the second end. The coupler nut has a threaded aperture to receive the shank of the bolt extending out from the first connection portion of an upper support.

The supports can be steel hollow support structures that can have a rectangular (including square) or other cross-sectional shape. The coupling nut can have the same cross-section shape as the support or a different shape. The axial hole has a first open area adjacent to the end of the support. The first open area can have the same cross-section shape as the coupling nut and is large enough to allow the nut to pass through. A second open area is axially inward and adjacent to the first open area. The second open area can have a circular cross-section with a diameter substantially the same as the maximum diameter of the first open area. The larger second open area defines inward facing shoulders adjacent to the first open area which prevents the coupler nut from being removed when rotated to a captured position. A third open area formed inward from the second area nut keeps the coupler nut from passing inward beyond the second area. The first open area can have the same shape or different shape as the support cross-section, such as square, and can be rotated thereto so that sides defining the first open area are not parallel to the sides of the support.

One or more locking holes can be provided in the end surface of the second connecting part and that extend through to the second open area. The locking holes are positioned so that when a locking pin is inserted into the locking hole, the locking pin restricts rotation of a coupler in the captured position within the second open area.

A diaphragm plate can be provided to connect the tops of horizontally adjacent vertical supports. The diaphragm plate has a plurality of bolt apertures that are positioned to align with the threaded apertures in coupler nuts mounted in the second connection portions of the adjacent supports. The diaphragm plate can also have vertically extending alignment members (such as circular or diamond profile pins or cones) that mate with corresponding alignment features in the first connecting portion of a vertical support being lowered therein.

Alignment holes can also be formed in the diaphragm plate and the second connecting portion and/or the coupler nut. The alignment holes are positioned so that when the coupler is in the captured position in the second connection part, the diaphragm plate can be positioned over the second connection part with the diaphragm alignment hole and coupler alignment hole axially aligned and the bolt aperture axially aligned with the axial hole in the second connector part. Locking bolts placed through the diaphragm alignment holes and into the coupler alignment holes can be used to temporarily hold the diaphragm plate in alignment over one vertical support while the vertical support from an upper module is lowered over another portion of the diaphragm. A bolt can also be temporarily inserted through the diaphragm plate into the coupler nut. Once the diaphragm is clamped in place under that other vertical support, the locking bolts and diaphragm plate bolt can be removed.

A lifting plate with the same basic shape as the coupler nut can also be provided. Instead of a threaded aperture, the lifting plate has a lifting eye. The lifting plate can be mounted in the second portion of the vertical supports (e.g., at the top) in the same manner as a coupler nut and the lifting eye used as a cable connection point for hoisting the module into place. When the module is correctly placed, the lifting plate can be removed.

Advantageously, the internal bolting configuration allows building modules to be connected without having to disturb existing weatherproofing. The diaphragm plate can also be reduced in size so that it only covers the tops of the adjacent vertical supports, reducing weight and material cost. The connection node system, as disclosed, allows a node of eight module corners (where four upper and four lower modules come together) to be securely joined together using only four bolts and an appropriately configured diaphragm plate. Because a connecting bolt is inserted through the top of the vertical support on an upper module and tightened using an elongated wrench assembly operated from above the upper, module workers need to spend less time working at the bottom of a module thereby increasing worker safety.

The bolted connection can resist tension as required by various building codes, even if the connection remains in compression during its use in all load cases. The bolt can be pre-tensioned during construction during the stacking procedure. This bolted connection turns individual module columns into continuous steel columns from the bottom to the top of the building. When rectangular modules are stacked, neighboring corner columns sit side by side in configurations of two (at the fa<IMG>ade) or four (internally). At the corners and irregular shaped areas of a building there may also be configurations of one (i.e. a single column) or three. Differently shaped modules, such as hexagons, would have more possible configurations. The diaphragm plate placed on top of columns connects side by side neighboring columns together during stacking. The column bolts from the modules above pass through holes in the diaphragm plate and the diaphragm plate operates to create a tying load path laterally between all columns in the group.

The chassis components can be assembled at the offsite module assembly facility by bolting the components together. This allows for efficient transport to the module assembly facility by transporting the pre-assembled frames and beams in a flat pack configuration rather than a volumetric configuration. This enables the industry best practice of not "shipping air".

The simple bolted construction at the offsite assembly facility eliminates any need for welded joints, thus reducing the time to assemble and inspect the components, and reducing the labor content overall. The lack of welding at the assembly facility and the construction site reduces the level of skill required to erect the building and lowers the overall cost of labor and inspection.

The bolted connections provide for significantly tighter control of build tolerances, allowing for stacking with a curtain wall fa<IMG>ade pre-installed on the modules. Components can be machined for tight tolerance assembly and then assembled and inspected to tighter tolerances without incurring significant cost.

The use of standardized components allows for efficiencies of scale in their production, such as development of tooling for the rapid setup of CNC machinery to perform the final machining of a cross beam, including the location of the bolt holes.

Further features and advantages of the invention, as well as structure and operation of various aspects of the methods and systems of the invention the implementations are disclosed in detail below with references to the accompanying drawings, in which:.

<FIG> is an illustration of a representative chassis <NUM> that can form the support structure of a prefabricated building module. The chassis comprises rectangular front and rear portions <NUM>, <NUM>, each having a pair of vertical supports <NUM> and top and bottom horizontal supports <NUM>. The front and rear portions <NUM>, <NUM> are connected to each other with horizontal beams <NUM>. The chassis can also have various other structural elements, such as posts or wall studs <NUM> and cross supports <NUM>. Vertical supports <NUM> are hollow support structures (HSS) and can have a rectangular (including square), or other shape cross-section. A square cross-section is illustrated.

The various vertical supports <NUM>, horizontal supports <NUM> and horizontal beams <NUM> are joined at each corner with a top connecting part <NUM> (for top chassis corners) or bottom connecting part <NUM> (for the bottom chassis corners). The connections of the horizontal supports and beams <NUM>,<NUM> to the connecting part <NUM>, <NUM> can be made using conventional techniques. In the illustrated embodiment, the vertical supports <NUM> and horizontal supports <NUM> are connected to a respective top and bottom corner connecting parts <NUM>, <NUM> using welds and the horizontal beams <NUM> are bolted in place at a joining assembly <NUM> such as a butt joint, shown in more detail in <FIG>. Other connection means could be used. Instead of a butt joint, a flange can extend from a corner connecting part <NUM> and be connected to a horizontal beam <NUM> in a bolted-together lap joint, shown in more detail in <FIG>.

In one configuration, the top and bottom connecting parts <NUM> are made of steel that is milled or cast into the proper configuration. The vertical supports are also steel. Vertical supports <NUM> can be provided, e.g., to a facility where the chassis are to be prefabricated, with the top and bottom connecting parts <NUM> already attached and the top and bottom ends of the assembly milled to create a flat bearing connection surface.

<FIG> is a diagram showing a side view of four chassis 100a, 100b, 100c, 100d stacked vertically and horizontally in a modular building configuration. During assembly of the building adjacent corner connecting parts are joined together to form connection nodes, such as nodes <NUM>, <NUM>. The number of horizontally and vertically adjacent corners in a given node depends on the arrangement of the modules. At a given node, both horizontally and vertically adjacent corners are attached to each other.

<FIG> is an exploded view of a connection node system <NUM> showing a top connecting part <NUM> and bottom connecting part <NUM> along with connecting hardware including a threaded coupler nut <NUM> (such as one having an integral threaded aperture or a separate captive threaded nut), a diaphragm plate <NUM>, bolt <NUM>, shims <NUM> and diaphragm temporary locking bolts <NUM>. As discussed in more detail below, during construction the coupler nut is placed into and locked within connecting part <NUM>. The diaphragm plate <NUM> is mounted over the top connecting part <NUM> and can be aligned and temporarily held in place with diaphragm locking bolts <NUM>. The diaphragm plate <NUM> can be used to connect connecting part <NUM> to one or more adjacent connecting parts <NUM> from adjacent chasses <NUM> and different diaphragm plate configurations can be provided according to the number of corners at a node, such as two along the facade and four at an interior connection. The bottom connecting part <NUM> is attached to the top connecting part <NUM> using bolt <NUM>.

<FIG> is a more detailed view of the top connecting part <NUM> and coupler nut <NUM>. <FIG> shows a cross section of the top connecting part <NUM> of <FIG> along line A-A. Top connecting part <NUM> is mounted at a top end <NUM> of a vertical support <NUM>. In one configuration, the top connecting part <NUM> fits into the opening at the top end <NUM> of vertical support and can be welded or otherwise affixed into place. Other ways of joining the top connecting part <NUM> to the vertical support <NUM> can be used as well.

The top connecting part <NUM> has a top surface <NUM>. Vertical support <NUM> defines a central axis <NUM>. An axial hole <NUM> runs from the top surface <NUM> to the interior of the vertical support <NUM>. Axial hole <NUM> is configured so that bolt <NUM> can pass completely through the top connecting part <NUM> and into the interior of the vertical support <NUM>. In a particular embodiment, the axial hole <NUM> has a diameter throughout that is greater than the maximum diameter D of the head <NUM> of bolt <NUM> so the bolt <NUM> can be in any rotational orientation and still pass through top connecting part <NUM> into the vertical support <NUM>. A narrower axial hole <NUM> could be provided if there is a need to prevent the bolt from passing into the vertical support unless it is in a correct rotational orientation.

The top connecting part defines a bottom surface <NUM> within the vertical support <NUM>. Depending on the configuration of the top connecting could merge into the inner side walls of the vertical support <NUM> so that the bottom surface <NUM> is minimized (or absent entirely). Joining assembly <NUM> can comprise one or more flanges welded or otherwise affixed to respective sides <NUM> of the top connecting part <NUM> to allow attachment of horizontal supports. A flat mount for a butt joint or other connection structure could be provided instead.

The axial hole <NUM> has a first portion that is adjacent the top surface <NUM> and defines a first open area <NUM> into which the coupler nut <NUM> can be placed. A second portion of the axial hole defines a second open area <NUM> adjacent the first open area <NUM>. The second open area <NUM> defines at least one shoulder <NUM> that is adjacent to the first open area <NUM>. The coupler nut <NUM>, first open area <NUM> and second area <NUM> are configured so that the coupler nut <NUM> when in an insertion position can pass through the first open area <NUM> and into the second open area <NUM> and can be rotated from the insertion position to a captured position where the shoulder <NUM> prevents removal of the coupler nut <NUM> through the first open area <NUM>.

The coupler nut <NUM> has a triangular, square, or other angular or curved geometric shape with a horizontal diameter that is not the same along all azimuth angles. In the illustrated embodiment, the first open area <NUM> has substantially the same shape as the coupler nut <NUM> and is sized to allow the coupler nut <NUM> to be easily inserted without too much play. The second open area <NUM> has a circular cross section large enough to allow the coupler nut <NUM> to spin freely without too much play so that the aperture <NUM> in the coupler nut <NUM> remains substantially aligned with the central axis <NUM>.

As discussed further below, the coupler nut is used for securing the top connecting part <NUM> to the bottom connecting part <NUM> in conjunction with the bolt <NUM>. While the shape of the nut plate <NUM> and the first and second open areas <NUM>, <NUM> can vary there is a balancing between increasing the surface area of the nut plate <NUM> that engages the shoulder <NUM> so that the assembly can withstand high forces involved in coupling chasses <NUM> together while also providing an opening large enough to allow easy access.

In a configuration where the vertical support <NUM> and coupler nut are both rectangular, the opening for the coupler nut is rotated relative to the vertical support <NUM> cross section, such as between <NUM> and <NUM> degrees, and in an embodiment substantially at <NUM> degrees. In this configuration, the final locked position of the coupler nut <NUM> engages a comparatively large amount of metal within the top connecting part <NUM> and increases the stress resistance of the total node assembly. Other relative rotational positions can be used for the design, including no rotation, which may make it easier to fabricate the top connecting part <NUM> by casting or other means.

Different shapes of the coupler nut <NUM>, first open area <NUM>, and second open area <NUM> could be used as long as capture of the coupler nut <NUM> in the second open area <NUM> can be achieved as discussed herein. In addition, the coupler nut <NUM> can be a single integral unit with the threaded aperture <NUM> formed directly therein. Alternatively, the threaded aperture <NUM> can be provided by a captive bolt <NUM> formed separately from and connected to the coupler <NUM>.

To retain the coupler nut <NUM> in the captured position, a locking pin <NUM> can be inserted through a coupler locking hole <NUM>. The locking pin <NUM> extends into the second open area <NUM> and functions to restrict rotation of the coupler nut <NUM> from its captured position. <FIG> is a cross section of the top connecting part of <FIG> illustrating a seated coupler nut and locking pins <NUM>. In the embodiment shown in <FIG>, two locking holes <NUM> are provided and positioned so that inserted locking pins <NUM> will bracket a corner of the coupler nut <NUM> and limit the amount the coupler nut can rotate so as to prevent its removal. In an alternative embodiment, locking holes <NUM> (not shown) can be formed in the coupler nut <NUM>. The locking holes <NUM> are positioned so the locking pin <NUM> can pass into the locking holes <NUM> in the coupler nut.

Returning to <FIG>, a third open area <NUM> can be formed beneath the second open area <NUM>. The third open area <NUM> defines shoulders <NUM> at the bottom of the second open area <NUM> that keep the coupler nut <NUM> within the second open area <NUM> so it does not fall into the vertical support <NUM>. In the illustrated embodiment, the third open area <NUM> has a circular cross-section with a diameter that is less than the diameter of the second open area but greater than the diameter D of the bolt head <NUM>.

<FIG> is a more detailed view of the bottom connecting part <NUM>. <FIG> shows a cross section of the bottom connecting part <NUM> of <FIG> along line B-B. Bottom connecting part <NUM> is mounted at a bottom end <NUM> of a vertical support <NUM> (shown in phantom in <FIG>). In one configuration, the bottom connecting part <NUM> fits into the opening at the bottom end <NUM> of vertical support <NUM> and can be welded or otherwise affixed into place. Other ways of joining the bottom connecting part <NUM> to the vertical support <NUM> can be used as well.

With reference to <FIG> and <FIG>, bottom connecting part <NUM> has a bore <NUM> that extends through it along a central axis. The bore <NUM> has an upper bore part opening <NUM> at a top <NUM> of the bottom connecting part <NUM> and a lower bore part opening <NUM> that opens at the bottom <NUM> of the bottom connecting part <NUM>. The diameter of the bore <NUM> at the upper opening <NUM> is greater than the bolt head <NUM> diameter D1 and the bore diameter throughout is greater than the diameter D2 of the shank <NUM> of bolt <NUM>. Between top and bottom of the bore <NUM> is a constricted area through which the bolt shank <NUM> but not the bolt head <NUM> can pass.

In the illustrated embodiment, the upper bore part is conical and ends at a shoulder <NUM> on which the head <NUM> of the bolt <NUM> can rest when the bolt <NUM> is inserted into the bottom connecting part. The lower bore part is cylindrical with a diameter large enough to allow the bolt shank <NUM> to pass through easily and to provide sufficient clearance to accommodate normal fabrication, assembly, and erection tolerances, but to also maximize the contact area under the head of the bolt. Various other configurations of the upper and lower bore parts <NUM>, <NUM> are possible. For example, the diameter of the bore <NUM> from the upper opening <NUM> to the shoulder <NUM> can be constant.

An alignment opening <NUM> can be provided in the bottom surface <NUM> and be configured to receive an alignment member <NUM> extending upwards from the diaphragm plate <NUM> during assembly of the connection node. The alignment opening <NUM> and alignment member <NUM> help to properly align the bottom connecting part <NUM> with the diaphragm plate and the top connecting part <NUM> in a lower chassis to which the diaphragm plate is connected. More than one alignment opening <NUM> can be provided. For example, multiple alignment openings <NUM> can be provided to allow the same bottom connecting part <NUM> to mount to a diaphragm plate <NUM> on the left or on the right.

<FIG> illustrate a method for joining chassis in a modular building using the connection node assembly. <FIG> shows a first chassis mounted to a foundation <NUM>. The foundation <NUM> has mounting points <NUM> to which the bottom connecting parts <NUM> of the chassis can be joined. The mounting points <NUM> can be modified versions of a top connecting part <NUM> or have another configuration for receiving bolt <NUM>. <FIG> shows an already assembled chassis <NUM>. It should be appreciated that the vertical support <NUM> with the top connecting part <NUM> and bottom connecting part <NUM> already connected can be provided as a single part for use during construction of a chassis <NUM>.

Because of the unique configuration of the connection node system, once the chassis is aligned over the mounting points <NUM> it can be fixed in place without requiring a worker at the base of the chassis or inside of the chassis. Bolt <NUM> is dropped or otherwise lowered through the central bore <NUM> of the top connecting part <NUM>. It passes through the hollow vertical support <NUM> and is captured by the bore <NUM> in the bottom connecting part <NUM>. An elongated wrench assembly <NUM> can be inserted through the top connecting part <NUM> and lowered through the vertical support <NUM> until the socket <NUM> at the end of the wrench seats on the head of <NUM> of the bolt. Wrench assembly <NUM> is then used to tighten the bolt <NUM> and secure the chassis in place on the foundation <NUM>. In an alternative embodiment, the bolt could be pre-inserted into the central bore before the chassis is lifted into place and temporarily held in place with wax, hot glue, or other similar substance.

<FIG> illustrates the connection of two adjacent top connecting parts 130a, 130b from horizontally adjacent chassis. A respective coupler nut <NUM> is mounted and locked into place as discussed above. The diaphragm plate <NUM> is then positioned over the top connecting parts 130a, 130b. One more leveling shims <NUM> can be added to adjust the vertical height of the diaphragm plate <NUM>. The diaphragm plate and shims have bolt apertures <NUM>, <NUM> through which a bolt <NUM> will later pass. To help align the aperture <NUM>, <NUM> with the aperture <NUM> in the coupler nut <NUM>, one or more alignment holes <NUM>, <NUM> are formed on the diaphragm plate <NUM> and shim <NUM> respectively. One or more corresponding alignment holes <NUM> are formed on the coupler nut <NUM>. When the coupler nut <NUM> is locked in place and the shim <NUM> and diaphragm plate <NUM> are properly positioned, the alignment holes <NUM>, <NUM>, <NUM> will be aligned. At this point locking bolts <NUM> can be inserted through holes <NUM>, <NUM>, <NUM> and serve to lock the diaphragm plate <NUM> and shim <NUM> in the proper place over the coupling nut <NUM>. A temporary bolt (not shown) can also be passed through the bolt apertures <NUM>, <NUM>, <NUM>. The position of a secured diaphragm plate can be surveyed to allow for repositioning of each floor to the building nominal coordinate system.

According to a particular method, when joining two adjacent top connecting parts 130a, 130b, the locking bolts <NUM> and temporary bolt are installed over only one top connecting part, such as 130a. Once a portion of the diaphragm plate <NUM> is secured to one chassis, such as chassis 130b, by the placement of another chassis above it (see <FIG>), the diaphragm plate <NUM> will then be held securely in place and the locking bolts <NUM> and temporary bolt can be removed so the locking bolts <NUM> do not interfere with the placement of the next chassis coming in. The temporary bolt also functions to close the main opening in the top connecting part to prevent water from getting into the hollow vertical support <NUM> if construction is occurring during wet weather. The bolt apertures <NUM> that receive the locking bolts <NUM> can have a diameter large enough to allow the locking bolts <NUM> to float in the holes to allow for misalignment. If misalignment is less of a concern, locking bolts <NUM> could be counterbored into the diaphragm plate <NUM> so removal is not needed.

The diaphragm plate <NUM> can be shaped and sized according to the number and arrangement corners of a chassis to be joined at the node. In an embodiment, the diaphragm plate <NUM> is configured so that it fully covers the top surfaces <NUM> of the top connecting parts <NUM> at the node and where the sides <NUM> of the diaphragm plate <NUM> are generally aligned with the exterior sides of the top connecting parts at that node. (See <FIG> discussed further below.

The configuration of the alignment members can vary in different diaphragm plates <NUM> according to where in the structure the node is located and the stacking sequence of the chassis. In an embodiment, close fit cones are placed on the diaphragm plates used near the fa<IMG>ade portions of the chassis to tightly control the position of the chassis in that area. Diamond cones are used on diaphragm plates at the other end of the chassis to control the rotation of the chassis. Depending on the stacking sequence and position, a given diaphragm plate can have anywhere from zero to four alignment members. Various different diaphragm plate configurations 210a, 210b, 210c are shown in <FIG>. Differently configured alignment members known to those of ordinary skill in the art can be provided to, for example, position the chassis in x/y or manage rotation of the chassis about the alignment cone. The alignment members can be integrally formed with the diaphragm plate or the diaphragm plate can have suitable mounting apertures and the appropriate alignment members installed separately.

<FIG> shows the installation of a third chassis over one of the chassis shown in <FIG>. With reference to <FIG> and <FIG>, an upper chassis is lifted into place, its lower corners are generally aligned with the top corners of the chassis below, and then the chassis is lowered into place. One or more alignment members <NUM> on the diaphragm plate <NUM> mate with the corresponding alignment opening <NUM> at the bottom of bottom connecting part <NUM> to guide the upper chassis into proper alignment so that the central axis of the vertical supports <NUM> in the upper and lower chassis are aligned. <FIG> shows a cross section view of a fully connected node assembly at an inner node where upper and four lower chasses come together.

According to a further feature, and as shown in <FIG> and <FIG>, a lifting plate <NUM> having a lifting eye <NUM> can be locked into the top connecting parts <NUM> in each corner of the chassis. The lifting plate has the same cross sectional shape as the coupler nut <NUM> and can be secured to the top connecting part in the same manner. Cables <NUM> can be connected to the lifting eyes for use in lifting the chassis into place. After placement, the substitute nut plate <NUM> can be removed. <FIG> shows one corner of a chassis <NUM> connected for lifting in this manner.

Returning to <FIG>, after the upper and lower chassis are aligned, bolts <NUM> can be inserted into the top connecting parts in the upper chassis, such as top connecting part 130c. The bolt <NUM> passes through the respective bottom connecting part <NUM> and engages the threaded aperture <NUM> in the coupling nut <NUM> mounted therein. The bolt <NUM> is then tightened using the elongated wrench assembly <NUM> (see <FIG>) to couple the top and bottom connecting parts <NUM>, <NUM> at each corner together. The bolted connection turns individual module columns connected along a vertical axis into continuous steel columns from the bottom to the top of the building. The bolted connect also clamps the diaphragm plate <NUM> between the chassis' columns and creates a tying load path laterally between all columns in the group. Once portion of the diaphragm plate <NUM> is clamped between one pair of chasses <NUM>, any temporary bolts used to hold the diaphragm plate <NUM> in place over the top connecting parts <NUM> of other chassis <NUM> can be removed.

Advantageously, disclosed node system <NUM> allows node horizontal and vertical chassis to be coupled to each other with only the top connecting parts <NUM> of each chassis <NUM> being exposed on the top <NUM> of an otherwise weather sealed chassis, such as shown in <FIG> which illustrates the top of four adjacent chassis prior to installation of the diaphragm plate <NUM>. Once multiple modules are stacked, the nodes will define a rectangle having dimensions W by V. The diaphragm plate <NUM> which is used in this configuration will generally be a rectangle having dimensions W' by V' where W' is substantially equal to or less than W and V' is substantially equal to or less than V so that the entire top surface of the vertical supports will be covered. The vertical diaphragm plate could also be sitting in a recess rather than proud of the fireproofing and weatherproofing. Such a recess can be formed by using vertical supports <NUM> that do not extend fully to the top of the horizontal supports.

Advantageously, the top of the chassis (apart from the top connecting parts) and any weather barrier formed on the top can remain undisturbed and the risk of water or other contaminants entering the interior of the chassis from the top reduced or avoided entirely.

In addition, the entire assembly can be done from the top of each chassis. Workers are not required to access any internal portions of the chassis, thereby limiting the possibility for internal damage and reducing worker risk.

Claim 1:
A connection system for use in connecting prefabricated building modules together, the system comprising:
a bolt (<NUM>) having a head (<NUM>) with a head diameter and a shank (<NUM>) with a shank diameter;
a coupler (<NUM>) having a threaded aperture therein sized to threadedly receive the shank of the bolt; and
first and second support elements (<NUM>);
each respective support element (<NUM>) comprising:
an elongated hollow body having a central axis (<NUM>), first and second ends with respective first and second outer surfaces substantially perpendicular to the central axis, an interior, a first connection part (<NUM>) at the first end and a second connection part (<NUM>) at the second end;
the first connection part (<NUM>) having a bore (<NUM>) therein along the central axis with a first opening (<NUM>) adjacent the interior and having a first diameter, a second opening (<NUM>) in the first outer surface and having a second diameter less than the first diameter, and a shoulder (<NUM>) within the bore between the first opening and second opening, the head diameter of the bolt being less than the first diameter and greater than the second diameter and the shank diameter of the bolt being less than the second diameter, wherein the bolt can pass partially through the bore with the shank extending therefrom; and
the second connection part (<NUM>) having an axial hole (<NUM>) therein running from the second outer surface to the interior and having a diameter throughout greater than the head diameter of the bolt and an inward facing shoulder (<NUM>) therein, the axial hole configured to allow the coupler (<NUM>) in an insertion position to be moved from outside of the body adjacent the second end through the axial hole past the shoulder and to permit rotation of the coupler within the axial hole from the insertion position to a captured position where the shoulder blocks motion of the coupler towards the second end;
wherein the first connection part (<NUM>-<NUM>) of the first support element (<NUM>) can be axially connected to the second connection part (<NUM>) of the second support element (<NUM>) by inserting the bolt (<NUM>) into the bore in the first support element (<NUM>) via the second connection part of the first support element (<NUM>) and rotating the bolt so the shank engages the threaded aperture in the coupler (<NUM>) when the coupler is mounted in the captured position within the axial hole of the second connection part of the second support element (<NUM>).