Patent Application
20080168741
Applicants claim priority of Canadian Application, Ser. No. 2,573,687, filed Jan. 11, 2007.
The present invention relates generally to building construction and in particular to a wall fabrication system and method.
Housing is a critical aspect of social living. The construction of houses and other dwellings is therefore a well-known and highly refined art. Construction techniques and esthetic styles are well known for single family dwellings, detached and semi-detached houses, condominiums, apartment buildings, town houses, and the like.
Automation is also broad reaching and used heavily in a broad range of industries and is used to build cars, trucks, planes, electronics, appliances and many other products. Automation techniques are increasingly being applied to the housing industry, and indeed are used heavily in the manufacture of modular and panelized homes. Automation is not yet, however, widely applied to the manufacture of traditional site-built homes.
When insulating walls in traditional site-built homes, it is common to employ skilled labourers to stuff bats of fiberglass insulation within the cavities defined by wall studs. However, it can be difficult to properly fill the cavity, and the fiberglass bats can be prone to sagging so that the upper portions of the wall are not properly insulated. Likewise, not all cavities have uniform shapes and so the bats need to be cut to size, leaving the possibility for gaps. Another disadvantage with fiberglass insulation is that a properly placed vapour barrier is also required. Such a vapour barrier is usually provided via plastic sheets that are applied to the interior side face of the wall. The vapour barrier can be difficult to install, and in any event presents extra cost and time in the home construction process. Another problem with vapour barriers is that mould growth and air leakage can result from punctures that can easily occur in the plastic sheets. Also, application of a moisture barrier in a damp area could actually trap existing moisture within the wall, particularly where the plastic sheeting becomes wrinkled, with all the attendant problems thereto.
Another common type of insulation is closed cell foam. Closed cell foam can be acquired in rigid sheets, and thus are not prone to sag in the same manner as fiberglass. However, the sheets of foam still need to be cut to size in order to fill irregular shaped cavities. Also, a vapour barrier can still be preferred when using sheets of closed cell foam.
It is also known to spray closed cell foam in a liquid form into the wall cavities. A spray gun can be used to fill the cavity with the closed cell foam, which then cures and forms an insulating barrier. However, this reintroduces a version of the sagging problem with fiberglass insulation, as the liquid insulation tends to flow downwards in the wall cavity, resulting in an uneven distribution of the insulation within the wall cavity. Overspray is also a serious problem—should the foam be applied to the studs, it can be difficult to attach drywall or other paneling or covering to the wall. Labourers spraying closed cell foam are also exposed to significant environmental hazards and are preferably equipped with gear to reduce inhalation of harmful fumes from spraying closed of cell foams.
In an aspect of the invention there is provided a wall section comprising a first set of substantially parallel supports and a second set of substantially parallel supports disposed substantially perpendicular to the first set. The parallel sets of supports are affixed to each other at their junctions. The wall section also comprises a covering applied to one side of the supports. The covering and the sets of supports define a plurality of cavities in the wall section. The wall section also comprises a curable, flowable material that is downwardly injected into one or more of the cavities while the supports are in a horizontal position. Once the material is cured, the wall section can then be moved to the construction site and used to fabricate a home.
The wall section can further comprise a second covering that is applied to a second side of the supports that is opposite to the first side of the supports.
The foam material can adhere to both the first covering and the supports in such a manner that the covering is adhered to the supports by the foam material.
The covering can be drywall, or wood sheathing, or any other type of wall paneling.
The supports can be made from wood or metal or any other suitable material.
Depending on the choice of flowable material, when the flowable material cures into a solid form, a torsional and tensional rigidity of the wall section can be increased thereby.
Depending on the choice of flowable material, when the flowable material cures the insulation factor of the wall section can be increased thereby. The thermal resistance (or R value) per inch of flowable material typically surpasses the R value per inch of traditional fiberglass bats. For example, a traditional bat of 3.5 inch fiberglass has an R value of about 12, whereas three inches of closed foam has an R value of about eighteen. In general terms, traditional fibreglass bats have an R value of about 3.4 per inch of fiberglass, whereas closed cell foam has an R value of about six per inch.
Depending on the choice of flowable material, when the flowable material cures it can provide an air barrier from one side of the wall section to the other side of the wall section. Furthermore, the flowable material can be chosen to have a low vapour permeance, and, when coupled with a vapour-barrier primer (applied as a paint to the drywall), then a vapour barrier can be formed that is suitable to substantially eliminate the need for plastic sheeting as a vapour barrier.
The flowable material can be closed cell foam. Closed cell foam can result in increased strength, increased insulation (thermal resistance), and act as an air barrier and has a low vapour permeance.
In other aspects, the flowable material can be open cell foam.
Another aspect of the invention provides a method of insulating a wall section of a site-built home. The wall section comprises a first set of substantially parallel supports and a second set of substantially parallel supports that are disposed substantially perpendicular to the first set. The parallel and vertical supports are affixed to each other at their junctions. The wall section also comprises a covering positioned on one side of the supports. The covering and the sets of supports define cavities in the wall section. The method comprises:
orienting the wall section horizontally such that the cavities face upwards; and,
injecting a curable flowable material downwardly into one or more of the cavities.
The method can further comprise applying a second covering to a second side of the supports that is opposite to the first side of the supports.
The method can further comprise applying the flowable material to both the first covering and portions of the supports that are perpendicular to the first covering and waiting until the foam material cures such that the covering is adhered to the supports.
Another aspect of the invention provides a system for manufacturing a wall section comprising one or more framing stations for producing wall sections. The wall sections comprise a first set of substantially parallel supports and a second set of substantially parallel supports disposed substantially perpendicular to the first set of supports. The wall sections include a covering applied to one side of the supports. The covering and the sets of supports each define cavities in each wall section.
The system can also comprise one or more insulation stations for receiving wall sections from the framing stations and for injecting a curable flowable material downwardly into one or more of the cavities while the supports are in a horizontal position.
The framing stations and the insulation stations can be configured to produce and insulate, respectively, wall sections that have different configurations.
The system can further comprise automation equipment, such as robotic equipment, for the framing stations and the insulation stations.
The system can further comprise a computer configured to control the automation equipment in the framing stations and the insulation stations according to a production schedule in order to continuously produce and insulate a plurality of wall sections having different configurations.
A wall fabrication system and method is provided. In an aspect, an assembly line comprises one or more framing stations and one or more insulation stations. The framing stations are configured to build a wall frame consisting of wall studs and a covering such as drywall. The wall studs and drywall define cavities in the frame which are to be insulated. Optionally, mechanical components such as electrical, plumbing, central vacuum, telephone and the like can be installed into the wall section. The wall section is then transferred to the insulation station. The insulation station is configured to fill the cavities in the wall frame with closed cell foam which is injected in flowable form into each cavity.
The invention will now be described, by way of example only, with reference to certain embodiments and the attached Figures in which:
Referring now to
It should be understood that terms such as “horizontal” and “vertical” are used for convenience to assist in understanding the discussion herein, but do not imply herein that studs of a frame need to be arranged in such a manner.
Studs 54, 58 can be wood and/or metal and/or any other suitable type of home framing material for a traditional site-built home. Studs 54, 58 are affixed to each other using nails, staples and/or any other type of suitable fastener. Drywall 62 (typically a plurality of sheets of drywall) is affixed to frame 60 with nails, staples, screw and/or glue or any other type of suitable fastener. As will be discussed in greater detail below, drywall 62 can be only partially affixed to frame 60, so that drywall 62 is secured to frame 60 so as to simply hold drywall 62 in place so that wall section 50 can be further processed, but not secured to the extent that would traditionally be needed to fully secure drywall 62 to frame 60 in final installation on site. For example, the Ontario Building Code 1977 states that “Spacing of ⅝″ long steel drill screws shall be not more than 300 mm along supports, except that on vertical surfaces the screws may be spaced at 400 mm where the supports are no more than 400 mm o/c.” The teachings herein can obviate traditional fasteners and/or mitigate the number of screws that are required according to the Ontario Building Code.
Wall section 50 is thus characterized by a plurality of cavities 64-1, 64-2, 64-3 . . . 64-9. (Generically, cavity 64, and collectively, cavities 64). Wall section 50, in a present embodiment, is also characterized by a door 68, and a window 70.
It should be understood that the size of wall section 50, the configuration, placement and number of studs 54, 58, and the configuration, placement and number of cavities, and the configuration, placement and number of cavities of doors or windows (if any) therein is not particularly limited. While not shown in
Referring now to
Assembly line 74 thus includes one or more framing station(s) 78 and one or more insulation station(s) 82. Insulation station 82 will be discussed in greater detail below. Framing station 78 is configured to produce wall section 50. It is also contemplated that assembly line 74 is “flexible”, so that while framing station 78 is configured to produce wall section 50, framing station 78 is also configured to produce wall sections that have configurations that are different than wall section 50. In other words, various wall sections produced on assembly line 74 can be different, according to a desired production run for different configurations of traditional site-built homes. Assembly line 74 can also be fully or partially automated, with computers instructing robotic equipment to manufacture each wall section. In a presently preferred embodiment, assembly line 74 is substantially automated, including the transfer of wall sections from station 78 to station 82. Thus, assembly line 74 includes a central scheduling computer 86 that maintains a production schedule 90 with production runs for station 78 and station 82. Production schedule 90 thus includes instructions for the configuration of wall section 50 and configurations for every other wall section that is to be produced using framing station 78 and insulated at insulation station 82. Computer 86 is configured to deliver instructions to operators and/or robotic equipment in framing station 78 as to the configuration of each wall section to be produced. Computer 86 is also configured to notify insulation station 82 as to the configuration of each wall section 78 that has been produced so that insulation station 82 can fulfill the insulation task.
Referring to
Controller 106 is in turn connected to computer 86 and is configured to receive instructions from computer 86 as to the configuration of the particular wall section 50 within station 82 as found on production schedule 90.
Injector 102 is configured to dispense closed cell foam 110 in a flowable form into each cavity 64. Injector 102 is connected to a reservoir (not shown) of foam that is located proximal to station 82. In a presently preferred embodiment, rails 94 and 98 are substantially horizontal and wall section 50 is also positioned substantially horizontally, so that injector 102 is above wall section 102 and all foam 110 dispensed from injector 102 flows substantially downwardly.
Controller 106 is thus configured to instruct gantry 91 so as to move injector 102 above the extent of each cavity 64, and to issue instructions to a valve associated with injector 102 that causes injector 102 to either dispense foam 110, or to cause injector 102 to “shut off” and not dispense foam. The valve can also be variable so that the rate of flow of foam 110 is variable. Whether injector 102 is dispensing foam or not, injector 102 is movable along rails 94, 98 according to instructions from controller 106.
Referring now to
In a presently preferred embodiment, controller 106 is preprogrammed with a plurality of paths to follow in order to fill each cavity 64. Controller 106 is preprogrammed to move injector 102 within each cavity 64a according to each predefined path, and dispense a bead of foam 110 along that path. Controller 106 is also preprogrammed to move injector 102 between each cavity 64a without dispensing any foam. The rate of travel of injector 102, and flow rate of foam 110 can be chosen in order to optimize speed of filling each cavity 64, reduce and/or minimize the overall amount of travel of injector 102 within each cavity 64a and/or reduce and/or minimize the amount of travel of injector 102 between each cavity 64a where injector 102 is not dispensing any foam. In addition to the foregoing, however, the size of the bead that is injected is chosen so as to optimize any settling and/or expansion that may occur within each cavity 64a and the cure times of the foam. It can be desired to control the manufacturing steps for each station 78 and 82 such that the cycle time for each station 78 and 82 are substantially the same, and thus the operation of injector 102 can be configured accordingly.
Referring now to
Referring now to
The contents of Table I can thus be converted into programming instructions for controller 106, with each cavity 64a being filled by injector 102 in the order according the sequence in Table I.
Referring now to
However, there is no gap between foam 110 and drywall 62. This underscores one of the advantages of the present invention, as foam 110 adheres to drywall 62, thereby affixing drywall 62 to frame 60 in a manner that can be more secure than at least some prior art methods which include the sole use of nails and/or staples and/or glue. Since the use of mechanical fasteners (e.g. nails and/or staples) can be substantially eliminated, or at least reduced, drywall 62 is much less susceptible to the phenomenon of “nail-pops” whereby drywall nails, over time, appear to be driven out of wooden studs 54, 58 and protrude from the surface of drywall 62, with an unsightly effect. This annoying phenomenon can be common on traditional wooden wall panels, as moisture evaporates from studs 54, 58 and giving the appearance of pushing the nails out of the wood frame as the wood shrinks away from the frame. It can be one of the most significant causes of warranty claims on new homes and therefore it is strongly desirable to obviate nail-pops.
Also, as another advantage, since cavities 64 are filled while wall section 50 is horizontal, the depth of foam 110 is substantially uniform. Likewise the insulating properties are also substantially uniform along the length of wall section 50. Likewise, the mechanical adherence of drywall 62 to frame 60 is substantially uniform throughout the entire extent of drywall 62.
Also, as another advantage, the substantially uniform fill of each wall section 50 can obviate the need for a traditional vapour-barrier of plastic sheeting to be applied, particularly when a vapour-barrier primer is applied to the wall section 50.
Also, as another advantage, the filling of each wall section 50 with foam 110 can increase the overall strength, both in torsion and in tension, of each wall section 50. As a result, when wall sections are manufactured in a facility for shipping to the construction site, wall sections manufactured according to the teachings herein are more resilient during the shipping process and less susceptible to damage than traditional, prior art wall sections.
It is believed that the teachings herein can, in certain applications, obviate the use of fasteners for drywall 62 to stud 58 altogether, as the adhesion between the foam and the drywall 62 and stud 58 is sufficient. Also the use of closed cell foam, can permit the reduction in the thickness of an exterior wall cavity from six inches to four inches, since the closed cell foam has an R value per inch that is greater than the R value per inch of traditional fiberglass insulation bats. This reduction in wall cavity thickness reduces the amount of lumber used and reduces stresses on the environment. Thus, a four inch wall cavity using the teachings herein can have the same, or better, air-conditioning and heating costs as a six inch wall cavity that employs traditional fiberglass bats. As a still further advantage, an engineered ventilated station can be configured to thereby reduce exposure to fumes given off during application. When foam is sprayed vertically into wall cavities on a construction site, the operator has to wear ventilation gear, yet an engineered ventilation system can mean that the operator need wear no gear when foam is sprayed using the teachings herein. Further, in a factory environment as described herein, the option exists to substantially completely recover the gases and prevent them from release into environment, and there by substantially reduce off-gassing into the environment.
Referring now to
The present invention thus provides, amongst other things, a novel system and method for manufacturing wall sections of houses by providing an assembly line for producing and insulating wall sections.
While the foregoing describes certain specific embodiments of the present invention, it should be understood that variations, combinations and sub-sets of those embodiments are contemplated.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2,573,687 | Jan 2007 | CA | national |
