Exterior wall panel system

Abstract

An exterior wall panel system is provided. The exterior wall panel system includes a wall panel and a wall support member. The wall panel includes an exterior facade attached to a panel perimeter frame having a head frame with inner male panel joint legs, a jamb frame, and a base frame with female panel joint pockets. The wall support member includes an extruded structural member having a panel mounting flange and a factory-installed panel fastener on the panel mounting flange. The panel fastener includes a fastener stem having a stem diameter and a fastener head. The head frame or jamb frame has factory-fabricated jamb fastener holes for interfacing with the panel fastener.

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims the benefit of U.S. Provisional Patent Application No. 63 / 381,473, filed Oct. 28, 2022, the content of which is hereby incorporated by reference in its entirety.

[0002] The present invention relates to an exterior wall panel system and a method of assembling the same. The exterior wall panel system includes pre - assembled exterior wall panels having spaced panels that support vertical or horizontal orientation.

Background Art

[0003] First - generation air - operated systems use externally - exposed aluminum panel frame systems that are used in many jobs around the world, mainly to solve the water leakage problem of curtain walls. Second - generation air - operated systems use externally - concealed frame systems that use structural silicone caulking between the facade and the panel frame to meet the aesthetic requirements of the exterior of the building. Structural silicone caulking is designed to be filled into the design pocket between the panel frame and an external facade such as an aluminum plate, ACM (abbreviation for aluminum composite material), or conventional IG (abbreviation for insulating glass). This design requirement is a factory quality control problem because the caulking cannot be visually inspected after it is applied. This problem occurred in one U.S. air - operated system job. Third - generation air - operated systems are externally - concealed frame systems that use structural tape between the facade and the panel frame to solve the quality control problem of the silicone caulking design. Third - generation air - operated systems have been successfully used in some jobs around the world. Fourth - generation air - operated systems use panels having a large ventilation space between an outer glass plate and an inner glass plate, mainly to improve the insulation and sound - proofing values. The outer glass plate is fixed to the hidden frame behind it using structural tape. The inner glass is finished on the panel frame using a gasket system.

[0004] In all four generations described above, vertical air-actuated mullions are required along the panel vertical frame for drainage and structural connection between the panel vertical frame and the water seal fingers of the air-actuated mullions. Due to structural connection requirements, a vertical joint of approximately 3 / 4 inch (19 mm) is required for the minimum mullion bay distance of approximately 36 inches (914 mm) to assemble the panels. Recent building exterior aesthetic requirements dictate concealed frame curtain wall systems with 1 / 4 inch (6.4 mm) gridline gaps and 1 / 16 inch (1.6 mm) acceptable gap construction tolerances. The fourth-generation air-actuated system does not meet this requirement.

[0005] In addition, some curtain wall consultants are dissatisfied with the excessive air leakage rates on the leeward walls of pneumatic systems, particularly on the higher panels. The air leakage test method specified by ASTM (American Standard of Test Method) for energy loss concerns is based only on the air leakage rate on the windward wall with the prevailing daily wind speed (i.e., positive wind pressure). Excessive air leakage rates on the leeward walls (i.e., negative wind pressure) occur on pneumatic systems during strong wind events such as hurricanes, typhoons, or cyclones. This particular behavior of pneumatic systems is known as "pressure ventilation" in strong wind conditions, and is considered good behavior because structural safety concerns in strong wind conditions outweigh concerns about daily energy loss. However, some curtain wall consultants are concerned that during the structural phase of mock-up testing, the specified maximum negative pressure cannot be reached due to capacity limitations of the laboratory equipment (i.e., the negative pressure ventilation behavior cannot be overcome). [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] Therefore, the present invention proposes an improved exterior wall panel system to solve the above-mentioned conventional problems. [Means for solving the problem]

[0007] In at least one embodiment, the present invention provides an exterior wall panel system. The exterior wall panel system includes a wall panel and a wall support member. The wall panel includes an exterior facade attached to a panel outer frame having a head frame with internal male panel joining legs, a vertical frame, and a base frame with female panel joining pockets. The wall support member comprises an extruded structural member having a panel mounting flange and a factory-installed panel fastener on the panel mounting flange. The panel fastener comprises a fastener stem having a stem diameter and a fastener head. The head frame includes a factory-made head fastener hole for joining with the panel fastener on site. The head fastener hole comprises a lower part having a hole size larger than the fastener head and an upper part having an elongated hole with a width slightly larger than the stem diameter.

[0008] In at least one embodiment, the present invention provides an exterior wall panel system. The exterior wall panel system includes a wall panel and a wall support member. The wall panel includes an exterior facade attached to a panel outer frame having a head frame with an inner male panel joining leg, a vertical frame, and a base frame with a female panel joining pocket. The wall support member comprises an extruded structural member having a panel mounting flange and a factory-installed panel fastener on the panel mounting flange. The panel fastener comprises a fastener stem having a stem diameter and a fastener head. The vertical frame has factory-made vertical frame fastener holes for joining with the panel fastener during panel assembly. The vertical frame fastener hole comprises a lower part having a hole size larger than the fastener head and an upper part having an elongated hole with a width slightly larger than the stem diameter. [Effects of the Invention]

[0009] A preferred embodiment of the present invention provides an exterior wall panel system having one or more of the following advantages (1) to (10). (1) To significantly reduce labor in the factory where the panels are assembled, we provide an external concealed frame wall panel design with structural tape for both visible panels and spandrel panels. (2) Provide an external hidden frame wall panel design with a variable minimum grid line gap without changing the basic panel frame. (3) Eliminates the need for on-site labor to install the rain screen member and water seal member on the panel head frame of the air-operated panel. (4) Eliminate the minimum acceptable panel width limit, giving complete freedom in the design of the external aesthetic grid lines. (5) Install any panel fasteners to assemble wall panels without on-site labor. (6) Ensure consistent good quality of assembled walls by changing the most important and difficult on-site quality control items into consistent and easy procedures for factory quality control items. (7) Provides approximately the same air leakage rate in the windward wall and the leeward wall. (8) Provide a rapid on-site method for replacing individual panels anywhere on the wall. This can significantly reduce curtain wall maintenance costs in the case of partial wall damage due to hurricanes or earthquakes, as well as when replacing malfunctioning panels such as solar or dynamic glass panels. (9) In addition to eliminating the need for facade reinforcement on long spandrel panels using aluminum plates or ACM as the exterior facade, it provides a significant structural improvement against negative wind loads. (10) Eliminate the problem of late panel position recovery of air-operated panels after floor drift caused by storms or earthquakes.

[0010] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings in order to facilitate understanding of the technical content, features, and effects of the present invention. [Brief explanation of the drawing]

[0011] [Figure 1] This is a partial vertical cross-sectional view of an exterior wall panel system according to a first embodiment of the present invention. [Figure 2] This is a partial horizontal cross-sectional view of an exterior wall panel system according to the first embodiment of the present invention. [Figure 3] This is a partial rear view of the head frame and vertical frame of the first embodiment of the present invention. [Figure 4] This is a rear view of an assembled wall panel according to the first embodiment of the present invention. [Figure 5] This is a partial vertical cross-sectional view of an exterior wall panel system according to a second embodiment of the present invention. [Figure 6] This is a partial horizontal cross-sectional view of an exterior wall panel system according to a second embodiment of the present invention. [Modes for carrying out the invention]

[0012] Because it is necessary to refer to multiple figures frequently, the following conventions for element numbering are used in this section: (1) All elements are numbered with three digits, and (2) the first digit of the element is the number of the figure in which the element is illustrated and / or illustrated. For example, element 108 is illustrated and / or illustrated in Figure 1, element 203 is illustrated and / or illustrated in Figure 2, and so on.

[0013] This invention relates to an exterior wall panel system and a method for assembling the same. The exterior wall panel system includes pre-assembled exterior wall panels having spaced-out panels supporting vertical or horizontal mullions. The wall panels consist of exterior facade panels fixed to a backup frame. The backup frame consists of two parallel horizontal members known as head frames and still frames in an interlocking male / female joint design between two adjacent panels, and two parallel vertical members known as jamb frames. The panels can be used for a single function, which is an external aesthetic function, or for a full-function curtain wall panel, such as an air-actuated system known in the industry. This invention uses an air-actuated system as an example to demonstrate the advancements in curtain wall panel assembly technology.

[0014] For the first embodiment of the present invention, refer to FIGS. 1 and 2. FIG. 1 shows a cross-section of the base frame 104 of the upper spandrel panel 100 and a cross-section of the head frame 105 of the lower visible panel 101, which form the small horizontal external panel joint 102 and the small horizontal internal panel joint 103. The joints 102 and 103 preferably have the same dimensions so that the weight of the spandrel panel 100 is positioned on the head frame 105 in the case of floor-to-floor deflection without buckling the unprotected bottom end of the external spandrel facade 106. An aluminum plate or ACM is generally used for the spandrel facade 106. The edge of the external visible facade 107 is protected by a small additional aluminum angle 108 fixed to the head frame 105 near the panel perimeter line using spaced fasteners 109 having a peripheral sealing caulking 110.

[0015] The bottom of the head screw hole 300 on the screw head side of the screw 209 has a gentle slope 121 from the bottom of the head screw hole 300 to the upper edge of the head of the head screw 209, which forms a small gap 122 at the bottom edge of the head of the head screw 209. The gap 122 is designed to be the degree of compression of the seal tape 208 recommended by the tape manufacturer.

[0016] The composite foam panel 112 supported by the spaced setting blocks 113 is generally used behind the external spandrel facade 106 to improve the insulation value and is glazed together with the glazing bead 114. The spaced air inlet holes 115 are provided in the I-shaped support members for insulation.

[0017] The inner visible facade 116 of the visible panel 101 is glazed with the spacer frame 117 and the glazing bead 114.

[0018] Both the external spandrel facade 106 and the external visible facade 107 are fixed to the panel frame using the structural tape 111.

[0019] The head frame (not shown) of the spandrel panel 100 is the same as the basic head frame 105 without the angle 108. The base frame (not shown) of the visible panel 101 is the same as the base frame 104 except for the added small angle 108. The vertical frame 211 has the same external shape as the base frame 104 of the spandrel panel 100, except for the absence of the air inlet holes 115.

[0020] In summary, the advantage achieved by the present invention is to provide an external concealed frame wall panel design with structural tape for both visible and spandrel panels, thereby significantly reducing factory labor in assembling the panels. However, the small angle 108 can be manufactured as an integral part of each panel frame member of the visible panel 101, by trading off this advantage with additional factory labor in manufacturing the angle 108 and fastening it to each panel frame using fasteners 109.

[0021] In the case of the visible panel 101, the dimensions of the exterior joints 102 and interior joints 103 can be changed by changing the size of the angle 108 without changing the basic outline of the head frame 105. In the case of the spandrel panel 100, the dimensions of the exterior joints 102 and interior joints 103 can be changed simply by changing the distance of the spandrel facade edge 118 to the structural tape 111.

[0022] In summary, the advantage achieved by the present invention is to provide an external hidden frame wall panel design having a variable minimum grid line gap without changing the basic panel frame.

[0023] The rain screen member 119 and the water seal member 120 are integral parts of the head frame 105. Therefore, the advantage achieved by the present invention is the elimination of on-site labor required to install the rain screen member and the water seal member on the panel head frame of the air-operated panel.

[0024] Figure 2 shows a horizontal section of an air-operated mullion 201 with an air-operated spandrel panel 202 installed on the right and an air-operated visible panel 203 installed on the left, forming a small external vertical joint 204. Vertical rainscreen gaskets 205 are factory-installed on both sides of the mullion head 207. Vertical waterseal gaskets 206 are factory-installed on both sides of the air-operated mullion 201. Compressible single-sided adhesive sealing tape 208 and panel head screws 209 are factory-installed on both sides of the mullion 201. Screws 209 or 309 are factory-installed at the design position at the gauge projection depth through the sealing tape 208 and panel mounting flange 212 to allow for field panel joining. The vertical frame 211 of panel 202 or 203 is not structurally joined to the mullion 201 against negative wind loads, and therefore, panel 202 or 203 can move freely in and out during assembly, regardless of panel width, even with the small joint 204. This means that the advantage achieved by the present invention is the elimination of the minimum acceptable panel width limitation, giving complete freedom in external aesthetic grid line design. The panel is moved into place and locked into the factory-installed head screws 209 on the adjacent mullion using special head screw holes 300. This procedure eliminates the on-site labor required to fasten the panel. Thus, the advantage achieved by the present invention is the assembly of wall panels without on-site labor to install any panel fasteners. Because the screws 209 and 309 are factory-installed with precise gauge penetration distances into the panel mounting flanges 212, the most critical and difficult on-site quality control item in the panel fastening procedure (too tight or too loose) is replaced by a consistent and controllable factory procedure. Thus, the advantage achieved by the present invention is to ensure consistent good quality of the assembled wall by replacing the most critical and difficult on-site quality control item with a consistent and easy factory quality control item.

[0025] Figure 3 shows a rear view of one of two upper panel corners having a head screw hole 300. The other side of the upper panel corner is the opposite side of the drawing. The diameter of the notch bottom circle 301 is slightly larger than the size of the head of the head screw 209. The width 302 of the upper slot is slightly larger than the diameter of the head screw 209. Because the two head screw holes 300 are on the same head frame, very tight manufacturing tolerances can be achieved during factory production. Line 304 is the top of the male panel joint leg 123. Line 305 is the bottom line of the inner panel joint 103. Line 306 is the mitered joint line between the head frame 105 or 504 and the vertical frame 211 or 600.

[0026] At least one optional vertical frame screw hole 307 for joining with vertical frame screws 309 can be used in each of the vertical frame frames 211 or 600 to reinforce and strengthen the vertical frame frames 211 or 600 against negative wind loads. The position of the vertical frame screw holes 307 is subject to the cumulative tolerances of cutting the panel frame and assembling the miter corners; therefore, the vertical frame screw holes 307 are changed from head screw holes 300 having elongated bottom holes 308, and the theoretical installation position of the vertical frame screws 309 is below the top of the vertical frame screw holes 307. This change ensures panel joining with both head screws 209 and vertical frame screws 309.

[0027] The vertical frame screws 309 prevent lateral deformation of the vertical frame 211 or 600, as well as torsional rotation due to deflection of the external spandrel facade 106 or external visible facade 107 under negative wind pressure. In fact, the pressure ventilation behavior of the air-operated system is significantly reduced to eliminate concerns of several curtain wall consultants.

[0028] The panel assembly procedure is described below. (1) The panel is bent from the outside inward, allowing the heads of the head screws 209 and vertical frame screws 309 on two adjacent mullions to join simultaneously with the notched bottom circles 301 and elongated bottom holes 308 of the respective screw holes 300 and 307. In this process, there is no limitation on the minimum panel width that is acceptable in the present invention. (2) When the screw heads of the head screw 209 and the vertical frame screw 309 pass through the notched bottom circle 301 and the elongated bottom hole 308 of the respective screw holes 300 and 307, the panel weight causes the panel joints to form horizontal panel joints 102 and 103, and the installation position is the position where the head screw 209 contacts the top of the head screw hole 300 and takes up the static load of the panel. The gap 122 makes it very easy to start this process without compressing the air seal tape 208, and the designed degree of compression of the tape 208 is achieved automatically. (3) The above procedure automatically inserts the vertical frame screws 309 into the installation position.

[0029] The air seal performance can be explained by referring to Figures 2 and 3 simultaneously, as listed below. (1) The optional vertical frame screws 309 are positioned near the center of the air seal tape 208 (i.e., at the same left and right positions as the screws 209, as shown in Figure 2). Referring to Figure 2, the vertical frame screws 309 prevent lateral movement of the vertical frame 211 under positive or negative wind loads. (2) Under any wind load conditions, the rotational moment of the vertical frame 211 or 600 due to the deflection of the external facade is resisted by the vertical frame screws 309. Under positive wind load conditions, the edges of the air seal tape 208 near the glazing bead 114 are compressed to achieve a good air seal. Under negative wind load conditions, the edges of the air seal tape 208 near the tips of the air seal legs 210 of the vertical frame 211 are compressed to achieve a good air seal. The advantage achieved by the present invention due to the air seal performance under the above loads is that it provides substantially the same air leakage rate on the windward and leeward walls.

[0030] Due to the air-sealing behavior under load, the factory-installed vertical frame screws 309 at the mid-height of the panel can be designed for loose, easy connection with the screw holes 307.

[0031] The procedure for replacing individual panels anywhere on the wall is described below. (1) A hoisting device having multiple power suction cups is used on the external facade of the panel above the panel to be replaced. (2) Roll the panel upward to bottom out the upper horizontal internal panel joints 103 until the open gap above the panel to be removed is suitable for removing the panel. This step is not difficult as it only requires overcoming the point contact friction force at the top of the head of the screw head 209 due to the gap 122. A simple balancing position from the inside of the panel with a suction cup may be required to prevent the screw 209 from coming out of the head frame 105 when the screw head of the screw 209 reaches the area within the notch bottom circle 301. For example, if the joint 103 is "1 / 4" and the horizontal panel joint and joint depth is "1 / 2", rolling it upward to bottom out the three joints 203 provides enough space (3 / 4) to remove the lower panel. (3) Maintain an open space and install replacement panels. (4) Slowly lower the hoist, and all the above panels will automatically return to their original positions due to their own weight. (5) Once the winding device and replacement panel are ready, the above procedure is estimated to take less than one hour.

[0032] In summary, the advantage achieved by this invention is to provide a rapid on-site method for replacing individual panels anywhere on the wall. This can significantly reduce curtain wall maintenance costs in cases of partial wall damage caused by hurricanes or earthquakes, as well as when replacing malfunctioning panels such as solar or dynamic glass panels.

[0033] Figure 4 shows a rear view of an assembled wall panel 400 having all four corners and detached intermediate sections of four outer frame members (heads are 105 or 504, bases are 104 or 502, and vertical frames are 211 or 600). For long horizontal wall panels 400, the panel can be reinforced and strengthened against negative wind loads using at least one optional intermediate head screw hole 401 joined to the head screw 209. The shape of the screw hole 401 is identical to that of the head screw hole 300. For long vertical panels, the vertical frame 211 or 600 can be reinforced and strengthened against negative wind loads using at least one optional intermediate vertical frame screw hole 307 on each vertical frame 211 or 600 joined to the vertical frame screw 309. This reinforcing effect of the vertical frame screw 309 is the same as the effect of conventional reinforcing behind the spandrel panel facade 106. However, as explained below, conventional reinforcing materials do not offer the following significant advantages of vertical frame screws 309.

[0034] For panels without vertical frame screws 309, the vertical frame 211 or 600 is a simple support beam to resist outward bending and deflection due to negative wind loads in the span from the head frame 105 or 504 to the base frame 104 or 502. When one intermediate vertical frame screw 309 is used at an intermediate height in the panel, the vertical frame 211 or 600 becomes a continuous double-span beam with a span equal to half the span of the simple support span in the case without vertical frame screws 309. As a result of the following structural analysis, the structural benefits against negative wind loads include (1) a 75% reduction in bending stress and (2) a 97% reduction in maximum outward deflection.

[0035] Structural analysis of vertical frame (1) Double span condition (one vertical frame screw at an intermediate height) M=WL 2 / 8 = 0.125WL 2 D=WL 4 / 185 = 0.005405WL 4 Here, M = maximum bending moment W = Uniform negative wind load L = Span of the structure D = Maximum deflection (2) Simple span conditions (no screws on vertical frames) Structural span = 2L M=W(2L) 2 / 8 = 0.5WL 2 D=5W(2L) 4 / 384 = 0.208333WL 4 (3) Ratio of moment coefficient to deflection coefficient a. Ratio of bending moment coefficients = 0.125 / 0.5 = 0.25 This means that a 75% reduction (1-0.25=0.75) in maximum bending moment and stress is achieved by vertical frame screws at the mid-height of the panel. b. Ratio of deflection coefficients = 0.005405 / 0.208333 = 0.03 This means that a 97% reduction in maximum deflection (1-0.03=0.97) is achieved by the vertical frame screws at the mid-height of the panel.

[0036] Due to the effects described above, the use of vertical frame screws 309 offers significant structural advantages, in addition to eliminating the need for transverse panel reinforcement used on conventional spandrel panel facades having aluminum plates or ACM. Therefore, the advantages achieved by the present invention are to eliminate the need for facade reinforcement on long spandrel panels using aluminum plates or ACM as the exterior facade, in addition to providing a significant structural improvement against negative wind loads. For screwless factory assembly of wall panels 400, a corner crimping method used in an air-operated system having mitered top corner lines 306 and mitered bottom corner lines 405 is preferred.

[0037] Another special structural behavior of first- to fourth-generation pneumatic systems is their ability to absorb story drift between floors by stress-free panel drift due to the space within the external pneumatic mechanism. Story drift between floors is caused by storms or earthquakes. Panel drift is caused by relative lateral sliding between male and female panel joints. However, the lateral frictional force within the panel joint due to the gasket causes small panel distortion. The lateral frictional force due to the gasket disappears over a long period of time, as experienced in pneumatic operation after a severe earthquake, requiring manual adjustment from the inside by the owner. When vertical frame screws 309 are used in this invention, story drift between floors is absorbed by stress-free relative sliding of screws 209 and 309 in their respective screw holes 300 and 307. Since both the head frame 105 and the vertical frame 211 are fastened to the pneumatic mullions 201, the panels return to their original positions with the mullions immediately after the event of story drift between floors. Therefore, the advantage achieved by the present invention is to eliminate the problem of late panel position recovery of air-operated panels after floor-to-floor drift caused by storms or earthquakes.

[0038] For a second embodiment of the present invention, please refer to Figures 5 and 6. Figure 5 shows a cross-sectional view of a joined horizontal panel joint between two exterior wall panels 500 and 505, designed for a single performance function of external aesthetic features. A single aesthetic performance function allows for a highly simplified panel frame design by eliminating features such as watertightness and thermal insulation / sound insulation values. However, structural functionality against negative wind loads must be maintained. The most common application of this type of wall panel is covering masonry walls. Comparing Figure 5 with Figure 1, the panel frame design in Figure 5 is more simplified. To maintain adequate panel joint and release strength under negative wind loads, the panel interlocking design shown in Figure 5 is male-type Panel joining The configuration is the same as shown in Figure 1, with the leg portion 501 on the head frame 504 of the lower wall panel 500 and the female mold pocket 503 on the base frame 502 of the upper wall panel 505.

[0039] Figure 6 shows a cross-sectional view of a vertical panel joint between two adjacent single-function exterior wall panels 604. For mitered frame corner designs, the outer shape of the vertical frame 600 is the same as the outer shape of the base frame 502. For long wall panels 604, the vertical frame 600 is fastened to a simplified vertical mullion 602 using optional vertical screws 309. The screws 209 or 309 are factory-installed at the design position at the gauge projection depth through sealing tape 208 and panel mounting flanges 601 to allow for on-site panel joining. The simplified mullion 602 is fastened to a backup structure (not shown), such as a masonry wall, using fasteners 603. Depending on the strength of the negative wind load, the panel height, and the number of vertical screws 309 per vertical frame 600, the dimension "a" on all panel frames can be designed to meet the structural strength requirements for negative wind loads. The air sealing tape 208 is used to eliminate metal-to-metal contact noise caused by dynamic wind.

[0040] It is important to note that the following items are crucial for the invention to be assembled on-site. (1) Since the head screws 209 and vertical frame screws 309 are installed at the factory on the support mullions 201 or 602, the screw positions must coincide with the positions of screw holes 300 and 307 on the panel with very tight tolerances. Therefore, high-precision CNC machines must be used for factory manufacturing. (2) Since two screw holes 300 and two screw holes 307 on each panel 202 or 203 or 604 must be locked in place to corresponding pre-installed screws 209 and 309 on adjacent mullions 201 or 602, the mullion positions in the left-right direction must be installed with very tight tolerances. This requirement can be met by an anchoring design for air-operated mullions in curtain wall applications, as described in U.S. Patent No. 10,370,843, or by using a gauge bar between two adjacent mullions 602 during anchoring operation of mullions 602 in a single-function wall panel system. (3) In curtain wall designs, horizontal panel joints must be designed to accommodate the effects of maximum inter-floor deflection due to the design live load on the floor. As a maximum inter-floor deflection of 3 / 4 inch (19 mm) is commonly specified, in order to maintain structural integrity for horizontal male / female panel joint designs with small joints, the movement of mullion joints must be isolated from floor deflection, as described in U.S. Patent No. 6,598,361. (4) As a conclusion from items 2 and 3 above, the present invention in curtain wall applications can be recognized as a fifth-generation air-actuated system.

[0041] The foregoing description does not mean to limit the present invention to any particular material, geometric shape, or orientation of the elements. Various modifications to the shape of the panels and the external form of the panel frames and / or support mullions can be made without departing from the scope of the present invention and will be apparent to those skilled in the art as they are intended to be within the scope of the present invention. The embodiments described herein are presented only as examples and should not be used to limit the scope of the present invention.

[0042] The embodiments described above are for illustrative purposes only and do not limit the scope of the present invention. Accordingly, any equivalent modifications or variations in shape, structure, features or spirit disclosed by the present invention are also included within the scope of the present invention.

Claims

1. A wall panel including an external facade attached to a panel outer frame, wherein the panel outer frame includes a head frame having male panel joining legs and a vertical frame, A mullion comprising a panel mounting flange and a factory-installed panel fastener on the panel mounting flange, wherein the factory-installed panel fastener comprises a fastener stem having a stem diameter and a fastener head, the mullion includes The head frame is provided with a factory-made head fastener hole for joining the factory-installed panel fastener on-site, and the factory-made head fastener hole comprises a lower part having a hole size larger than the fastener head and an upper part having an elongated hole with a width slightly larger than the stem diameter. An exterior wall panel system wherein the vertical frame is provided with factory-made vertical frame fastener holes for joining with the factory-installed panel fasteners during panel assembly, the factory-made vertical frame fastener holes having a lower part with a hole size larger than the fastener head and an upper part with an elongated hole whose width is slightly larger than the stem diameter, and there is a distance between the upper part of the elongated hole and the factory-installed panel fastener to which it is fixed.

2. The exterior wall panel system according to claim 1, wherein the factory-manufactured head fastener hole has a slope from the bottom to the top that forms a gap between the bottom end of the fastener head and the factory-manufactured head fastener hole.

Images