US 3661683 A
The present invention relates to a patch press, particularly but not exclusively adapted to use in repairing airplane surfaces by adhesively patching a double plate over the damaged area.
Claims available in
Description (OCR text may contain errors)
United States Patent Engelet al.
[4 1 May 9, 1972  PATCH PRESS  Inventors: Harry C. Engel; Edward J. Ardolino, both of Harve de Grace, Md.
 Assignee: Airline Systems, Inc., Harve de Grace,
 Filed: Nov. 3, 1970  Appl.No.: 86,437
 US. Cl 156/580, 156/94, 100/211, 269/21, 269/22  int. Cl. ..B30b 9/22, 1329b 19/00  Field of Search ..l56/94, 580; 100/211; 144/281; 269/21, 22
 References Cited UNITED STATES PATENTS 2,960,147 11/1960 Ferrell 100/211 2,987,098 6/1961 Daniel ..l56/94 Primary Examiner-Douglas J. Drummond Attorney-Fidelman, Wolffe & Leitner [5 7] ABSTRACT The present invention relates to a patch press, particularly but not exclusively adapted to use in repairing airplane surfaces by adhesively patching a double plate over the damaged area.
The patch press itself involves a longitudinally split rectangular frame that has clamped therein a cover member which may be heavy duty fabric such as canvas that extends across the framed area and beyond and which serves to carry a plurality of suction cups at the periphery thereof so that the press may be mounted on and adhered to the undamaged surface around the region to be patched with the patch inside the frame.
Sealed inside the frame and secured thereto is an inflatable,
suitably valved diaphragm into which air or other gas can be pumped. That portion of the cover member inside the framed area acts as an outside reinforcement for the inflatable diaphragm, so that the forces generated when inflatable diaphragm is inflated and beats against the patch are transmitted directly to the suction cups.
The patch press is a portable, essentially self-contained unit which can be employed to hold a patch onto an airplane surface and to maintain the patch there under pressure long enough for the adhesive bond to cure.
10 Claims, 10 Drawing Figures Patented May 9, 1972 3 Sheets-Sheet l Patented May 9, 1972 3,661,683
3 Sheets-Sheet 2 "IIIIIIIIIIIIIIIIIIIIIIIIIIIIIII I/IIIIIII IIIIII/IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIL Patented May 9, 1972 3 Sheets-Sheet 5 OOOOOOOOOO PATCH PRESS The present invention relates to an apparatus adapted for use in quick fix, bonded repair systems wherein a patch is adhesively bonded over a damaged region of some surface. In particular, the apparatus is adapted for use in time-limited, field type, bonded repair of aluminum aircraft assemblies.
Modern day airplanes are now constructed with wing and other surface regions of structurally bonded honeycomb panels that can easily be dented, even ruptured locally as, for example, by a dropped wrench, a thrown rock, impact with a bird. Overall, the airplane remains operable and safe, yet, obviously, the damage must be repaired as soon as possible. Needed is a patch which will hold permanently, or, failing that, at least until a convenient time comes to make permanent repair of the damaged region.
A typical repair sequence involves cleaning up the damaged region and removing all dirt and finish from the sound area immediately around the damaged region. Typically, the dented and broken damaged region is filled with an adhesive or other filler material so that the surface of the damaged area is flush with that of the sound metal around the damage. A doubler or patch piece is then adhesively bonded to the damaged area with enough of an overlap onto sound metal to obtain an adhesive metal-to-metal bond adequate to hold the doubler in place. Typically, the doubler may overlap the damaged area from about 1%. to 4 inches in all directions.
Fortunately, high quality quick-curing adhesives are available commercially so that this repair procedure is effective. However, the efficacy of the adhesive bond depends largely upon application of a uniform pressure over the entire area of the doubler plate. In short, the doubler plate must be uniformly pressed against the skin surface regardless of whether the surface is horizontal, vertical, planar or curved. The present invention provides a portable, essentially selfcontained apparatus, i.e., a patch press, capable of applying compliant uniform pressure to the doubler plate being adhered over a damaged surface region, and maintaining such pressure until the adhesive has cured.
For further understanding of this apparatus, reference is now made to the drawing wherein:
FIG. 1 is a top plan view of the patch press;
FIG. 2 is a side view of the patch press;
FIG. 3 is a section taken along line 3-3 ofFIG. 1;
FIG. 4 is an enlarged partial section taken along the line 4- 4 of FIG. 1;
FIG. 5 is an enlarged partial section taken along line 5-5 of FIG. 1;
FIG. 6 is an enlarged partial section taken along line 6-6 of FIG. 1;
FIG. 7 is an exploded section taken along line 7-7 of FIG.
FIG. 8 is a top plan view of a modified form of the invention;
FIG. 9 is a bottom plan view of the device in FIG. 8; and
FIG. 10 is a side elevation of FIG. 8 with parts broken away.
As may be seen best in FIGS. 1, 2 and 3, the present patch press 10 is adapted to seat on a damaged panel 12 through means of a plurality of suction cup assemblies 14 disposed peripherally around the patch press 10. The damaged region 15, shadow illustrated in FIG. 1, is centered under patch press 10. FIG. 3 shows how patch press 10 is seated over a doubler patch 16 and uniformly applies pneumatic pressure thereto by a lower fluid tight elastic diaphragm 18 which form s'a portion of patch press 10. FIG. 2 shows the diaphragm 18 in a flaccid non-inflated state.
Patch press 10 further comprises a square (or rectangular) longitudinally split metallic frame 20 normally fabricated of aluminum. The upper frame member 22 and lower frame member 24 (FIGS. 4 and 5) are secured together by machine screws 26 or other conventional fastening elements (e.g., rivet, nut and bolt, etc.). Locked together between the split halves 22 and 24, are the several layers of sheet material which form part of the present patch press. FIG. 7 is an exploded view illustrating frame members and the several sheet layers in FIG. 7. The cover member is a heavy duty inelastic sheet 28, film or fabric, e.g., heavy canvas, which extends across the open area inside frame 20 and beyond frame 20, as is shown in FIG. 1. The heavy duty sheet 28 serves to carry suction cup assemblies 14 at the peripheral edges thereof. Directly beneath heavy duty sheet 28 is upper elastic diaphragm 30, which desirably may be a rubber sheet (synthetic, natural, or even an elastic resin). Optionally present is an adhesive layer 32 between diaphragm 30 and sheet 28, disposed either on the underside of sheet 28 or on the top side of diaphragm 30 to adhere the two layers together. The lower elastic diaphragm 18 previously alluded to is the bottom layer. Therebeneath is lower frame member 24. Normally, the same (rubber or rubber-like) material would be employed for both diaphragms. The extra layer 34 shown on FIG. 7 is a soft sealing ring 34 whose area is generally co-extensive with that of frame 20 and whose purpose is to provide an airtight seal between upper diaphragm 28 and lower diaphragm 18 so that the space therebetween can serve as a sealed off region into which pressurizing fluid may be added and removed as desired by way of air valve 36. Such valves are standard articles of commerce, e.g., an ordinary tire valve will sufiice, and the details thereof need not be described further. Optionally present may be a pressure gauge 38, should it be desirable to indicate the extent to which the volume inside diaphragms l8 and 30 has been pressurized.
The suction cup assemblies 14 disposed at the periphery of the heavy duty sheet 28 each'comprise (FIG. 6) a suction cup 40 which seats on panel 12 and a threaded shank 42 to which cup 40 is secured. The shank 42 passes up through a grommet 44 which provides a suitable opening in the sheet 28. A knurled internally threaded adjusting nut 46 mounted on grommet 44 is threaded to shank 42. By rotation of adjusting nut 46, the relative position of the grommet 44 and with it the sheet 28 can be adjusted with regard to suction cup 40. A groove 48 or some equivalent structure is provided as part of adjusting nut 46 to retain grommet and nut together and permit nut 46 to rotate freely.
The operation of patch press 10 is virtually self-apparent. Once the patching procedure has reachedthe point where a patch 16, e.g., a doubler plate, has been positioned over the damaged region 15 on panel 12, the patch press 10 may be.
centered over patch 16. The shank 42 of each suction cup assembly 14 is raised or lowered by rotation of adjusting nut 46 so that the various suction cups 40 conform to whatever local curvature exists on panel 12 and suspend the inelastic sheet 28 and frame 20 generally parallel to panel 12 spaced away from panel 12 so that frame 20 clears the highest point on panel 12. The lower diaphragm 18 will then rest on and around the patch 16 in a flaccid state as is illustrated in FIG. 2. However, when a fluid such as air or other gas is pumped into the space between lower diaphragm l8 and upper diaphragm 30, both diaphragms distend. The lower diaphragm 18, being relatively flaccid and unsupported, bears down upon patch 16 and ap plies a uniform pneumatic pressure across the entire area of the patch. The upper diaphragm 30 also distends, but only to the limits set by inelastic sheet 28 against which it bears. All the forces set up by pressurizing the space between diaphragms l8 and 30 are transmitted to the plurality of vacuum cup assemblies 14, tending to unseat vacuum cups 40. In practice, it has been found that moderate pressures, e.g., up to 20 psig, applied between diaphragms l8 and 30 can be withstood by a 12 inch frame patch press 10 constructed with eight standard suction cups 40 (3 inch diameter). It goes without saying that if the patch press 10 were larger than about the 12 inch frame and a 20 inch canvas sheet, the size of the exemplary structure illustrated, then more suction cup assemblies l4 (e.g., 16) may be provided at the periphery of sheet 28.
Standard materials of construction may be utilized for patch press 10. Certainly lower diaphragm 18 should be of an elastic extensible air tight material such asrubber sheeting and frame 20 should be a relatively rigid material, such as aluminum bar or sheet stock, but substitute materials are widely available and may be employed. For upper diaphragm 30, any air tight sheet material maybe employed. Rubber sheeting is convenient, mostly because the two diaphragms may then be identical, and the material of inelastic sheet 28 may then be selected without regard for air permeability. Heavy duty canvas sheeting is preferred for sheet 28. A less preferred altemative is to use a gas tight sheet material that can serve simultaneously for inelastic support sheet 28 and upper diaphragm An alternative more rigid mode of patch press is illustrated in FIGS. 8, 9 and 10. The patch press cover member 128 is a rigid sheet (e.g., aluminum) withthe vacuum cups 40 secured directly at the peripheral edges thereof, being attached to depending skirts l30j'lhe patch press mode illustrated in FIGS. 8 and 9 is particularly adapted for smaller patches and, advantageously, requires fewer members than the previously described patch press mode. Only lower diaphragm l8 and a single frame member 120 are required. Frame 120 is bolted or riveted directly to cover member 128 by fasteners 126. The metallic sheet material of cover 128 is air tight and rigid, so that the space between diaphragm l8 and cover 128 may be sealed off adequately by the sealing ring 34. Air valve 36 and pressure gauge 38 can be readily mounted in cover 128.
Omission of the shank mount for vacuum cups 40 in favor of mounting on depending skirt 130, permits an easy inclusion of a valve 150 at each cup (for breaking the vacuum).
The mode of patch press illustrated in FIGS. 8, 9 and 10 can be made with as little as two suction cups 40, one at each end of the center line, so that parts as narrow as the suction cups can be repaired.
Although the patch press mode of FIGS. 8, 9 and 10 is more rigid than the mode of FIGS. 1-7, the relatively thin, strong aluminum alloys employed for cover 128 are flexible enough to allow for attachment of the patch press to moderately curved surfaces.
Since airplane patching practice normally involves employment of a heat-curing adhesive, thepatch press of the present invention may include provision for heating patch 16. Obviously, steam might be introduced into the space above I diaphragm 18 to provide both heat and pressure. Alternatively, electric resistance wires. may be molded into lower diaphragm l8.
Allusion has already been made to the great extent to which the patch press is a self-contained, portable unit of wide applicability. The patch press is capable of use on curved surfaces. lt is'not sensitive to altitude, and can be employed on vertical surfaces, top surfaces, even on upside down surfaces. This versatility is quite advantageous, since damages rarely occur on the most convenient to patch top horizontal surfaces. Essentially, therefore, thepatch press may be used almost anywhere on modern-day airplanes, allowing high quality patching to be done remote from central maintenance stations.
Inasmuch as patching of airplanes is a substantial problem and the greatest use of the patch press may be in repair of aircraft structure, the present invention has been described within such context. Its use is not limited thereto. Similar circumstances and patch patterns exist in aluminum hulled and fiberglass boats where small damages are repaired by patching the surface. It is believed, then, that the present patch press has wider applicability than in the repair of aircraft structures.
What is claimed is:
1. A patch press comprising:
a frame clamping a multiplicity of layers therein;
a cover member clamped by said frame as the uppermost layer, said cover extending across the framed area and beyond said frame;
a plurality of suction cups peripherally mounted adjacent the outer edges of said cover member, said suction cups serving as the support elements for the patch press with said frame being supported thereby generally parallel to and in s aced apart relation to the surface being patched; a fluid Ug lt diap ragm extending acrossthe framed area beneath said cover member, said diaphragm being clamped gas tight by said frame and being of a flaccid elastic material; and
valve means for adding and removing fluid from the space 3. A patch press as in claim 1 wherein valve means are disposed in said cover member for admitting fluid under pressure to the space between diaphragm and cover.
4. A patch press as in claim 1 wherein a sealing ring coextensive with said frame and disposed between the diaphragm and cover member is clamped by said frame to provide the gas tight sealed space between said diaphragm and cover member.
5. A patch press as in claim 4 wherein said cover member is a heavy duty inextensible fabric and a second fluid tight diaphragm is interposed between the inextensible fabric and the sealing ring.
6. A patch press comprising:
a longitudinally split frame clamping a multiplicity of layers therebetween;
an inextensible sheet clamped by said frame as the uppermost layer clamped therein, said sheet extending across the framed area and beyond said frame;
a plurality of suction cup assemblies mounted adjacent the outer edges of said inextensible sheet around 'the periphery thereof, said suction cup assemblies serving as the support elements for the patch press with said frame being supported thereby generally parallel to and in spaced apart relation to the surface being patched;
an upper and a lower fluid tight diaphragm extending across the framed area, said diaphragms being clamped together in a gas tight seal by said frame, and forming two of the layers clamped by said frame,- the lower diaphragm at least being of a flaccid elastic material; and
valve means for adding and removing fluid from the space between said diaphragms; v
whereby the patch press may be mounted over a patched surface with the patch element positioned inside the framed area and said suction cups seated on undamaged portions of the surface so that when the space between the said diaphragm is filled with fluid under pressure, the lower diaphragm distends into full contact with the patch element applying pressure uniformlythereto.
7. A patch press as in claim 6 wherein both diaphragms are rubber, and the inextensible sheet is a heavy duty fabric.
8. A patch press as in claim 6 wherein a sealing ring coextensive with said frame and disposed between the diaphragms forms an additional layer clamped by said frame to provide a gas tight sealed space between said diaphragms.
9. A patch press as in claim 6 wherein the upper diaphragm is adhesively attached to the inextensible fabric.
10. A patch press as in claim 6 wherein each suction cup assembly comprises:
a suction cup mounted at the base end of a threaded shank;
an internally threaded adjusting nut means to which the inextensible sheet is secured, said adjusting nut means being threaded on said shank whereby the spacing between the inextensible sheet and each suction cup may be adjusted so that the patch press can be fitted to curved surfaces.