Method of constructing a shell for a room air conditioner/heat pump with lateral strength
View Patent ↗A method of manufacturing a shell from sheet metal for a room air conditioner/heat pump is shown. The sheet metal is stamped and formed to a U-shaped rectangular shell with open ends and a shell brace. Flanges on the outer edge of the U-shaped rectangular shell overlap at corners with (a) adjacent flanges or (b) the shell brace. Both the U-shaped rectangular shell and shell brace are inserted into an assembly machine where the corners are clinched and punched. The outermost flange at each corner is punched to a fixed diameter, but the innermost flange or the shell brace is only punched to a conical shape. Screws are inserted at each corner that pass through the fixed diameter to threadably engage only the conical shape of the innermost flange or shell brace.
1. A method of manufacturing a generally rectangular shell from sheet metal for a room air conditioner/heat pump comprising the following steps:
stamping a first sheet metal blank to form a predetermined shaped shell with holes and louvers therein;
stamping a second sheet metal blank to form a predetermined shaped shell brace;
first forming flanges on outer edges of said shell;
second forming of said shell into a U-shaped rectangle with said outer edge overlapping at corners of said U-shaped rectangle;
painting said shell and said angle brace after said stamping step, but before the next step of inserting;
inserting said shell and said shell brace into an assembly machine wherein (a) said shell brace is secured across an open end of said U-shaped rectangle and (b) corners are punched through (1) said overlapping outer edges and (2) said flanges and said shell brace;
during said punching, a conical shaped punch on an end of a cylinder moves inward towards a die at each corner of said open end of said U-shaped rectangle so that an outermost layer of said flanges are punched at said each corner to form outer punched holes having a diameter approximately equal to said cylinder, but an innermost layer of said flange or shell brace is punched to form a conical shaped hole aligned with said outer punched hole;
inserting screws through said outer punched holes for threaded connection with said conical shaped holes, but not with said outer punched holes, to draw said innermost layer against said outermost layer, said screws providing lateral strength to said generally rectangular shell.
2. The method of manufacturing the generally rectangular shell from sheet metal as recited in claim 1 including between said stamping step and said inserting step a third forming of said shell brace to create an angle there along for added strength and tabs on each end thereof.
3. The method of manufacturing the generally rectangular shell from sheet metal as recited in claim 2 wherein as part of said inserting step corners of said U-shaped rectangle are secured by attaching (a) said overlapping outer edges and (b) said outer edge and said shell brace.
4. The method of manufacturing the generally rectangular shell from sheet metal as recited in claim 3 wherein said attaching is by clinching.
5. The method of manufacturing the generally rectangular shell from sheet metal as recited in claim 4 or 1 wherein said cylinder of said conical shaped punch is slightly larger in diameter than said screws.
6. The method of manufacturing the generally rectangular shell from sheet metal as recited in claim 5 wherein said punch and said die have a stop to prevent said cylinder of said conical shaped punch from penetrating said innermost layer of said flange or said shell brace.
7. The method of manufacturing the generally rectangular shell from sheet metal as recited in claim 6 wherein a punch holder positions said punch and holds said punch during said punching, a stripper positioned adjacent said punch holder for removing said punch after said punching.
8. The method of manufacturing the generally rectangular shell from sheet metal as recited in claim 7 wherein a die holder holds said die in position during said punching.
9. A method of joining sheet metal to form a shell with lateral strength to protect an object therein, comprising the following steps:
stamping the sheet metal to a predetermined shape;
first forming said stamped sheet metal to have flanges on an outer edge thereof,
second forming of said stamped sheet metal into a container so that said flanges of said stamped and formed sheet metal overlap on at least one corner of said container to provide an inside flange and an outside flange;
securing a die against said inside flanges within said corner;
locating a punch adjacent to said die, but against said outside flanges, said punch having a conical section and a cylindrical section;
punching said outside flange to said cylindrical section to form a first hole of a predetermined diameter therein, but only punching said inside flange with said conical section to form a second, conical shaped hole therein;
inserting a screw through said first and second holes to threadably connect said inside flange at said conical shaped hole, said predetermined diameter being slightly larger than the diameter of said screw; and
tightening said screw to draw said inside flange against said outside flange.
10. The method of joining sheet metal to form a shell with lateral strength as recited in claim 9 , wherein said securing, locating and punching steps occur at each corner of said container.
11. The method of joining sheet metal to form a shell with lateral strength as recited in claim 9 , wherein said sheet metal is painted after said stamping step, but before said punching step.
12. The method of joining sheet metal to form a shell with lateral strength as recited in claim 9 , wherein said conical section is approximately 15° with respect to a centerline of said punch.
13. The method of joining sheet metal to form a shell with lateral strength as recited in claim 12 wherein said punch is held by a punch holder, a stripper being spring-loaded to said punch holder to remove said punch after said punching step.
14. The method of joining sheet metal to form a shell with lateral strength as recited in claim 13 wherein said conical section can vary plus or minus 5 degrees.
15. The method of joining sheet metal to form a shell with lateral strength as recited in claim 14 wherein said securing, locating and punching steps are performed inside an assembly machine.
16. The method of joining sheet metal to form a shell with lateral strength as recited in claim 15 wherein said outside flanges are clinched to said inside flanges.
17. The method of joining sheet metal to form a shell with lateral strength as recited in claim 16 wherein a cross brace is used versus said inside flange on one side of said container in the preceding steps.