CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims priority to U.S. provisional patent application Ser. No. 60/632,641 filed on Dec. 2, 2004.
This application generally relates to heat exchangers and more particularly relates to heat exchangers that incorporate internal baffles for directing fluid flow in the heat exchanger.
Now referring to FIG. 1, typical heat exchangers 100 include a core assembly 102 positioned between an upper 106 and lower 108 header tank. Core assembly 102 is traditionally comprised of alternating layers of cooling tubes 104 and fins 105. It is typical for fins 105 to be formed in a serpentine shape and to be fastened, at numerous contact points, to two adjacent cooling tubes. Each cooling tube 104 extends between spaced header tanks 106, 108 and through a side wall of spaced header tanks 106, 108. The ends of each of the tubes 104 extend to the header tanks 106, 108 and are sealed thereto typically by furnace brazing or the like.
Under normal operation, a first fluid flows from one header tank 106, 108 to the other header tank 106, 108 by way of a center passageway within each cooling tube 104. A second fluid, typically ambient air, passes over an outside surface of the cooling tubes 104 and the fins 106. If the second fluid has a lower temperature than the first fluid, the fluid in the heat exchanger 100 will be cooled as it flows between header tanks 106, 108.
In many applications, it is desirable to divide one or more of the header tanks 106, 108 into a plurality of chambers. Although a number of techniques are well-known for doing so, they all involve complex tooling, or labor intensive techniques. The present invention sets forth various systems and methods for compartmentalizing header tanks 106, 108 of heat exchangers 100. The present invention also sets forth numerous structures for attaching ancillary hardware to heat exchangers.
Further features and advantages of the invention will become apparent from consideration of the following description and the appended claims when taken in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a prior art heat exchanger;
FIG. 2 is a partial cross sectional view of an embodiment of a heat exchanger of the present invention;
FIG. 3 is a partial exploded view of the header tank and supporting components found within encircled portion 3 of FIG. 2;
FIG. 4 is an assembled view of the components of FIG. 3;
FIG. 5A-5J are various embodiments of a baffle and baffle/tube assemblies of the present invention;
FIG. 6 is a partial cross sectional view of an end portion of a header tank employing a baffle and a rubber isolator to mount a heat exchanger to an adjacent support structure;
FIG. 7 is a partial cross sectional view of a pass through baffle joined to a header tank;
FIG. 8 is a partial cross sectional view of a header tank employing a stop baffle and a pass through baffle wherein the pass through baffle engages an inlet/outlet tubular member to provide strain relief to the inlet/outlet tubular member;
FIG. 9 is a partial cross sectional view of a stop baffle and a pass through baffle wherein both the stop baffle and the pass through baffle perform a strain relief function for an inlet/outlet member;
FIG. 10 is a partial exploded view of a header tank, a saddle coupling, and an I/O member wherein the saddle coupling employs an integrated baffle;
FIG. 11 is a partial cross sectional view taken substantially through lines 11-11 of FIG. 10;
FIG. 12 is a partial cross sectional view taken substantially along lines 12-12 of FIG. 10;
FIG. 13 is a partial cross sectional view showing a header tank employing a stop baffle as a terminal end cap for the header tank;
FIG. 14 is a partial cross sectional view showing a header tank employing a standard radiator cap connector at a terminal end of the header tank;
FIG. 15 is a partial cross sectional view showing a joint between a header tank and a tabbed portion of a structural side member;
FIG. 16 is a partial cross sectional view showing a method of attaching a structural side member to a header tank by displacing material from the structural side member;
FIG. 17 is a partial cross sectional view of first and second heat exchangers wherein the header tanks of the respectively associated first and second heat exchangers are joined using mating members;
FIG. 18A is a side elevational view of a first and second heat exchanger assembly employing a connector plate to join the first and second heat exchangers along an end portion of their respectively associated header tanks.
FIG. 18B is a side elevational view of a first and second heat exchanger assembly employing a common side support member.
FIG. 19 is a partial cross sectional view taken substantially along lines 19-19 of FIG. 18.
FIG. 20 is a partial cross sectional view of an embodiment of a high pressure manifold connected to a baffle.
FIG. 21 is a partial cross sectional view of yet another embodiment of a high pressure manifold connected to a baffle.
FIG. 22A is a depiction of a pierce tool aligned with a work piece to be operated on by the pierce tool.
FIG. 22B is a depiction of a pierce tool after it has worked upon a work piece.
FIG. 22C is a side elevational view of the pierce tool of FIG. 22A.
FIG. 23A is a front elevational view of a tool having a piercing portion that includes a concave side profile.
FIG. 23B is a side elevational view of the tool of FIG. 23A.
FIG. 24A is a front elevational view of a tool having a profile with generally linearly tapered sides.
FIG. 24B is a side elevational view of a tool of FIG. 24A.
FIG. 25 is a side elevational view of a pierce tool which has pierced through a work piece while the work piece has an inner chamber which is exposed to pressurized fluid.
FIG. 26 is a pierce tool which has pierced through a work piece while an inner chamber of the work piece is exposed to atmospheric pressure.
FIG. 27 is a partial cross sectional view of a bell mouth opening created in a side wall of a work piece.
FIG. 28 is a partial cross sectional view of a bell mouth opening which has been formed by a pierce operation through the side wall of a work piece wherein the bell mouth opening has been threaded to accept a threaded fastener.
FIG. 29 is an assembly showing multiple pierce tools affixed to a tool base.
FIG. 30 is a front elevational view of a piercing apparatus used to pierce multiple slots in a work piece.
FIG. 31 is a partial cross sectional view taken substantially through lines 31-31 of FIG. 30.
FIG. 32 is the apparatus of FIG. 30 shown in an intermediate, descending position.
FIG. 33 is a partial cross sectional view taken substantially through lines 33-33 of FIG. 32.
FIG. 34 is the apparatus of FIG. 30 shown in a position just prior to pierce tools piercing a work piece.
FIG. 35 is a partial cross sectional view taken substantially through lines 35-35 of FIG. 34.
FIG. 36 is an enlarged view of a plunger assembly and associated components shown substantially within encircled portion 36 of FIG. 34.
FIG. 37 is the apparatus of FIG. 30 wherein pierce tools are positioned in the lower most portion of their downward stroke.
FIG. 38 is a partial cross sectional view taken substantially through lines 38-38 of FIG. 37.
FIG. 39 is an enlarged view of the plunger assembly and related components found within encircled portion 39 of FIG. 37.
FIG. 40 is a partial cross sectional view of another embodiment of a piercing apparatus having both upper piercing tools and lower piercing tools.
Now referring to FIG. 2, heat exchanger 200 includes upper header tank 206, lower header tank 208 and a plurality of cooling tubes 204 that communicate a fluid between upper header tank 206 and lower header tank 208. A structural side member 210 can, optionally, be used to bind upper header tank 206 to lower header tank 208 thereby giving the entire assembly greater mechanical strength than that which may be present if cooling tubes 204 were the sole means of tying upper header tank 206 to lower header tank 208. Optional structural side member 210 can be fastened to upper header tank 206 and lower header tank in any number of ways known to those skilled in the art. For example, member 210 can be brazed to an outer surface of the header tanks 206, 208, it can be mechanically fastened to the header tanks using mechanical fasteners (such as screws and the like) or, as is shown in FIG. 2, it can be received within an opening in a sidewall portion of header tanks 206, 208 and thereafter it can be fastened (e.g. furnace brazed) in place.
A rubber isolator or the like 212, 214 may be used to structurally mount heat exchanger 200 to an adjacent support structure 216. Rubber isolator 212, 214 not only acts as the means for transferring load from heat exchanger 200 to adjacent support structure 216 but it also acts as a vibration absorption member to absorb any vibrational movement existing between heat exchanger 200 and adjacent support structure 216.
In the heat exchanger embodiment shown in FIG. 2, the normal circuit traversed by the fluid which flows through heat exchanger 200 is shown generally by the direction of the arrows set forth in FIG. 2. Specifically, fluid enters 218 CHAMBER A by way of upper header tank opening 220. From CHAMBER A, the fluid flows downward through a plurality of cooling tubes 204′ into the left hand portion of CHAMBER B. Next, fluid flows from the left hand portion of CHAMBER B to the right hand portion of CHAMBER B and, thereafter, flows upward through cooling tubes 204″ to CHAMBER C within upper header tank 206. From CHAMBER C, the fluid exits 222 by way of upper header tank opening 224. In the above-referenced embodiment, it is desirable to eliminate fluid flow directly between CHAMBER A and CHAMBER C. If fluid were allowed to “leak” directly between CHAMBER A and CHAMBER C (without having to traverse through CHAMBER B) the cooling effect offered by cooling tubes 204 would be greatly reduced. One of the functions of stop baffle 226 is to prevent the direct passage of fluid from CHAMBER A to CHAMBER C. Other stop baffles 228, 230, 232 and 234 are present to confine the flow of fluid to one or more chambers within heat exchanger 200.
Now referring to FIGS. 2 and 3, upper header tank 206 may be formed with one or more openings 236, 238, 240, and 242 which are adapted to receive various components comprising heat exchanger 200. Specifically, openings 238, 240, and 242 are appropriately sized and positioned along a bottom surface of upper header tank 206 to accommodate respectively associated cooling tube 238′, 240′ and 242′. Opening 236 is sized and positioned to accept stop baffle 226.
Stop baffle 236 includes a bottom portion that generally conforms to the inner contour 246 of upper header tank 206. In the example set out in FIG. 3, the inner contour of upper header tank 206 is generally circular and accordingly, the bottom portion 244 of stop baffle 226 is generally circular. At least one of the sidewalls 248, 250 of stop baffle 226 includes a portion which is adapted to register with a mating member 256, 258 of upper header tank 206. In the embodiment shown in FIG. 3, portions 252, 254 include a notch and mating members 256, 258 include a tab 256, 258 which is sized and positioned to generally engage its respectively associated notch 252, 254. Mating member 256, 258 may be formed in upper header tank 206 in the same operation wherein opening 236 is formed in upper header tank 206. This process will be discussed more fully in conjunction with FIGS. 22A and 22B.
One of the traditional problems associated with fabricating heat exchangers is that it is difficult to maintain all of the components in their respective locations between the assembly process and the furnace brazing process. By fashioning baffle 226 with portions 248, 250 that mate with receiving members 256, 258 of upper header tank 206, baffle 226 will remain in its desired location until furnace brazing is complete. FIG. 4 shows the final assembly of all of the members shown in FIG. 3 after furnace brazing is complete.
Now referring to FIGS. 4 and 5A, mating members 256, 258 can be located such that they frictionally engage a side portion 252, 254 of stop baffle 226. By appropriately sizing and locating mating members 256, 258 they can be made to frictionally engage one or more side portions 252, 254 of stop baffle 226 such that stop baffle 226 can be easily inserted into opening 236 but thereafter the engagement between 256, 258 and respectively associated side portions 252, 254 offers some resistance against removal of baffle 226 from its registration with mating members 256, 258. In many applications, the removal resistance offered by the frictional engagement (i.e. interference fit) of baffle 226 and members 256, 258 is sufficient to keep stop baffle 226 properly located within opening 236 until furnace brazing can take place. If a given application calls for greater retention than that offered by the interference fit between baffle 226 and members 256, 258, members 256, 258 may be crimped inwardly (toward each other) thereby squeezing baffle 226 therebetween. FIG. 5D shows an embodiment where members 256, 258 have been crimped (i.e. deformed) inwardly thereby causing baffle 260 to be squeezed between members 256, 258. In an embodiment, mating members 256, 258 are sized and positioned to operatively engage a respectively associated notch portion 252, 254 of stop baffle 226. By fashioning stop baffle 226 with one or more notch portions 252, 254 an enhanced pull out resistance is made available to stop baffle 226.
Although the discussion of baffle 226 has thus far been focused on a stop baffle, other baffle types can be employed depending on the configuration of the heat exchanger 200 at hand. For example, in some heat exchangers, a stop baffle 260 is provided wherein the stop baffle 260 includes a mounting hole 278 or “eye” formed in a portion of stop baffle which extends from an outer surface of header tank 206, 208 (see FIG. 5B).
In another baffle embodiment (see FIG. 5D), a stop baffle 262 is provided wherein the stop baffle includes a flanged eye portion 264. The flanged eye 264 can be used in any number of configurations where mounting baffle 262 to an external component is desirable. An inner opening 266 of flanged eye portion 264 may be threaded to accept a threaded fastener.
In still yet another embodiment of a stop baffle, a stop baffle 268 may be fashioned having one or more grip fingers 270, 272 to attach to (or wrap around) an adjacent member such as a tube 274, structural member, or the like (see FIG. 5F). Stop baffle may be fabricated having two or more openings in the portion of the baffle 262 extending from the outer portion of header tank 206, 208. For example, the stop baffle 276 embodiment shown in FIG. 5G shows two openings 278, 280 formed in a portion of stop tab 276 which extends from header tank 206, 208. One of these openings, 278, is a conventional mounting eye (similar to that shown in FIG. 5B) and the other opening 280, is a flanged eye similar to that shown in FIGS. 5D and 5E.
FIGS. 5H and 5I show a stop baffle that includes a planar surface 284 that is intersected by two spaced planar surfaces 286, 288. The two spaced planar surfaces 286, 288 can be generally parallel to one another although it is not necessary for them to be parallel and the surfaces can be blended together at one of their end portions by way of a curvilinear surface 290.
Now referring to FIG. 6, one application for the embodiment of stop baffle 260 (see FIG. 5B) is in attaching a rubber isolator 212 to an end portion of header tanks 206, 208 for the purpose of mounting the end portion of header tanks 206, 208 to an adjacent support structure 216. As shown in FIG. 6, an opening 284 (mounting eye) is fashioned in stop baffle 260 such that a male receiving portion 286 of rubber isolator 212 resides within mounting eye 284. Additionally, rubber isolator 212 can be fashioned to surround 288, 290 an outer periphery of header tank 206, 208. An additional point of contact between isolator 212 and header tank 206, 208 can be established at a contact region 292 between rubber isolator 212 and stop baffle 260. An end portion 290 of rubber isolator 212 is sized to be received within an opening 292 of adjacent support structure 216. By engaging member 286 within mounting eye 284 and, in addition, establishing points of contact 288, 290, and 292, isolator 212 securely engages the assembly 206, 208, 260 such that it is positively supported by support structure 216 while still being vibrationally isolated therefrom.
Although the function of the baffle as it has been discussed so far has focused on a baffle type which blocks fluid flow, (i.e. stop baffle 226), there are some applications where it is desirable to have a baffle type that allows fluid to flow therethrough. Such a baffle type is shown in FIG. 7 which, in all ways resembles the stop baffle of FIGS. 5B and 5C except that the baffle has an opening 298 which allows fluid to pass through the baffle. This type of baffle is known as a “pass through” baffle. One application of the pass through baffle will now be explained in conjunction with FIGS. 7 and 8. Often times it is desirable to connect an inlet or outlet tubular member 300 with header tank 206, 208 (hereinafter I/O member). Although such a connection is relatively easy to achieve, the vibrational forces experienced under normal vehicle operation by the components of the heat exchanger 304 cause high stresses at the fixation points 302 (i.e. point of joining) between I/O member 300 and header tank 206, 208. If additional stress relief is not designed into the structure, it is highly likely that the joint 302 will prematurely fail. Pass through baffle 296 can be used to support I/O member 300 at a point 306 which is remote from the fluid tight point of connection 302 between I/O member 300 and header tank 206, 208. Pass through baffle 296 can be fitted with opening 278 which serves as a strain relief for I/O member 300. Once the assembly shown in FIG. 7 is joined with I/O member 300 and the entire assembly is furnace brazed (or otherwise joined together) it provides an excellent rigid structure which eliminates joint failure at connection 302. FIG. 8 depicts the combinatorial use of baffles 226, 296 inasmuch as a first baffle (stop baffle 226) is used on one side of connection 302 to prevent the flow of fluid from CHAMBER E to CHAMBER D, and a second baffle (pass through baffle 296) is used as a strain relief member for supporting I/O member 300 while still allowing fluid to pass from CHAMBER E to CHAMBER F. As will be understood by those skilled in the art, any number of baffles can be used in combination to create any number of fluid flow circuits within a heat exchanger to accomplish any number of functions described herein that are associated with the use of baffles.
In the embodiment of FIG. 9, both a stop baffle 226 and a pass through baffle 296 are used in a way such that they perform a strain relief function for I/O member 300. In the embodiment shown in FIG. 9, I/O member 300 passes through an opening in header tank 206, 208 thereby forming a junction between the two capable of transmitting fluid. This junction contains a high stress joint 302 which, if not adequately reinforced, may result in premature failure of the fluid connection between member 300 and header tank 206, 208. In order to relieve the strain at joint 302, an upper portion 304 of stop baffle 226 abuts I/O member 300 along a first side of I/O member 300 and an upper portion 306 of pass through baffle 296 abuts a second side portion of I/O member 300. Once the assembly as shown in FIG. 9 is furnace brazed, or the like, upper portions 304, 306 (at their points of contact with 300), form strong joints that reduces the strain on joint 302. This provides an assembly having excellent resistance against fatigue fracturing along joint 302.
Now referring to FIG. 10, if an even greater strain relief capacity is necessary than that of the arrangement shown in FIG. 9, the system of FIG. 10 can be used. The system of FIG. 10 includes saddle coupling 308 for relieving the strain formed at the joint 302 between I/O member 300 and header tank 206, 208. Saddle coupling 308 may be fabricated from any number of materials including stamped or cast metal and is fitted with an opening 310 to receive I/O member 300. Saddle coupling 308 includes laterally spaced legs 312, 314 which terminate into respectively associated crimp tabs 316, 318. Saddle coupling 308 also includes an integral stop baffle 320 which is sized and positioned to pass through opening 322 of header tank 206, 208. When saddle coupling 308 is assembled to header tank 206, 208, stop baffle 320 is receivingly engaged in opening 322 and crimp tabs 316, 318 can be squeezed around header tank 206, 208 such that they positively retain saddle coupling 308 to header tank 206, 208 (see FIG. 11). I/O member 300 can be fashioned with an upset 324 so that the maximum penetration of I/O member 300 into the inner cavity 326 of header tank 206, 208 is controlled. Stop baffle 320 performs the same function (i.e. prevents the passage of fluid) as the other stop baffles as discussed herein. Although baffle 320 is shown as a stop baffle, other baffle types (e.g. pass through baffles can also be incorporated into saddle coupling 308). After the assembly of FIG. 10 through FIG. 12 is joined (by furnace brazing or the like), a strong, fatigue resistant joint 302 is formed.
Now referring to FIG. 13, the end portion 326 of header tanks 206, 208 may be terminated in any number of ways. For example, stop baffle 226 can be used (in the manner already described herein) to form an end portion of header tank 206, 208. Once this assembly is furnace brazed (or otherwise joined) stop baffle 226 forms a fluid tight seal against the fluid contained within header tank 206, 208. Stop baffle 326 can be fashioned directly to an end portion of header tank 206, 208 (as shown in FIG. 13) or, the end portion 326 of header tank 206, 208 can be fitted with a standard radiator cap fitting 330 (see FIG. 14).
As shown in FIGS. 15 and 16, structural side member 210 may be fastened to header tank 206, 208 by inserting a tabbed portion 332 of structural side member 210 through a receiving opening of header tank 206, 208 and thereafter furnace brazing (or otherwise joining) the two members together. In an alternative embodiment, FIG. 16 depicts displacing the tab portion 332 of structural side member 210 such that it forms a mushroom head to mechanically interlock with header tank 206, 208. This mechanical interlock is not a replacement for furnace brazing (or other means of joining) but it merely re-enforces the mechanical strength of the joint entire unit once the assembly fabrication is complete.
It is often desirable to join two heat exchangers in an adjacent configuration, such is common in automobiles wherein the engine radiator is placed in close proximity to the air conditioning condenser. If such a juxtaposition of two heat exchangers is desirable, the arrangement in FIG. 17 can be used wherein the header tank 106 of the first heat exchanger 336 is formed with a first portion 340 that is engagingly received by a mating portion 342 of a second header tank 106′. If tanks 106, 106′ are formed by extrusion, portion 340 and mating portion 342 can be easily formed during the extrusion process 340, 342 may be continuous (i.e. formed without interruption) or they may be formed at intervals along header tanks 106, 106′. By using these mating portions 340, 342 the need for additional fasteners for joining first heat exchanger 336 with second heat exchanger 338 is eliminated. Portions 340, 342 may appear on both upper and lower tanks. It may also be desirable to fashion a rubber hood seal 340 to header tank 106 to form a seal between header tank 106 and the underside of the vehicle hood (vehicle hood not shown). If this is the case, an engagement tab 342 can be fashioned on header tank 106 for receiving a mating portion 344 of hood seal 340.
An alternative embodiment for using portions 340, 342 (formed into tanks 106, 106′) for joining first heat exchanger 336 with second heat exchanger 338 is shown in FIGS. 18 and 19. In this embodiment, a connector 346 is used which includes first and second openings to engage the first and second header tanks 106, 106′ of the respectively associated first and second heat exchangers 336, 338. Although connector 346 is shown as a single connector in FIGS. 18A, 18B, and 19, it is envisioned that a similar connector may be used to interconnect the bottom header tanks of the heat exchangers 336, 338. Side supports 210′, 210″ can be separate members (as shown in FIG. 18A) or they can be a single member (as shown in FIG. 18B). If side supports 210′, 210″ are fabricated from a single member, a stiffening bead 211 may be formed in the support 210′, 210″ to impart rigidity. Also, by constructing side supports 210′, 210″ from a single member, the need for connector 346 may be eliminated. Connector 346 and supports 210′, 210″ may be formed from steel stamping, plastic, or any other suitable materials. Stop baffles 226, 226′ may be used to form end caps for the header of first and second heat exchangers 336, 338.
Now referring to FIG. 20, a high pressure manifold 346 can be coupled to baffle 348 or it can be formed as an integral extension of baffle 348. Baffle 348 can be any style of baffle that has been described herein. High pressure manifold 346 is effective for coupling high pressure fluid connections such as those found in air conditioning condensers. High pressure manifold 346 includes upper half 350 and lower half 352. At least one of the halves 350, 352 is coupled to (or integrally formed from) baffle 348. Both of the halves 350, 352 may be coupled to two or more baffles 348 or, in an alternative embodiment, one of the halves 350, 352 may be connected to two or more baffles at two or more points along halves 350, 352. Baffle 348 is attached to an upper or lower header tank in the manner that has been discussed herein. Upper and lower half 350, 352 may be fabricated from a metal stamping with or without a cladding as required for assembly brazing. High pressure manifold 346 may be used to replace high pressure manifolds currently being used which are fabricated using an expensive extruded materials. The high pressure manifold 346 can carry one set of tubes (such as inlet tubes 354, 356) or two sets of tubes (such as inlet tubes 354, 356 and outlet tubes 358, 360). Tubes 354, 360 may be joined to upper half 350 by way of furnace brazing or the like. Lower tubes 356, 358 may be furnace brazed to lower half 352. Inlet tube 356 may be formed with an upset portion 362 and outlet tube 358 may also be formed with an upset portion 364. Upset portion 362, 364 form part of a shoulder portion used to compress their respectively associated O-rings 366, 368 when threaded fasteners 370, 372, and 374 are tightened. The high pressure manifold 346 forms an excellent high pressure seal for transferring high pressure fluids through inlet tubes 354, 356 and outlet tubes 358, 360 while avoiding the cost of expensive extruded materials.
FIG. 21 shows an alternative embodiment to the high pressure manifold of FIG. 20. In the embodiment of FIG. 21, upper half 350 is identical to lower half 352. Accordingly, only one set of tooling is required to manufacture high pressure manifold 346 of FIG. 20. Each tube 354, 356, 358, 360 is connected to (by furnace brazing or the like) an extruded opening in either the upper half 350 or the lower half 352 of the assembly. Each half 350, 352 includes a notch 376, 378 for receiving an O-ring 366, 368. Depending on the thickness of members 350, 352 and the maximum operating pressures of the fluids carried by manifold 346, a center fastener 372 may or may not be required.
Now referring to FIGS. 22A and 22B, header 206, 208 may be formed using the following processes. Header 206, 208 can be fabricated from any tubular material (such as extruded or welded tube). Header 206, 208 can have a smooth wall (as shown in FIG. 22A) or can be fabricated having fins or ribs running longitudinally along the header (see 340, 342 in FIG. 17). One technique for forming either tube slots or baffle slots (hereinafter generically “slots”) in header 206, 208, is to use hydropiercing technology. In the most simplest manifestation, hydropiercing technology includes pressurizing header 206, 208 with a pressured fluid and then concurrently acting on it with one or more tools 380 to form tube slots, baffle slots, or any other type of opening through the side wall of header 206, 208. In order to form a slot in header 206, 208, tool 380 is pushed against header 206, 208 until it pierces the side wall of header 206, 208 and achieves the position generally shown in FIG. 22B. Preferably, when tool 380 is in its lower-most position (see FIG. 22B), the chisel point 388 slightly coins the inside (i.e. bottom) surface of 206, 208. Tool 380 may have a rectangular cross section throughout its body portion 382 and terminate into a piercing portion 384. The piercing portion 384 when viewed from a front elevational view may have a radius 386 which generally matches the inner radial diameter R of header 206, 208. When viewed from a side profile (see FIG. 23C), tool 380 terminates into a chisel point 388 which may begin 391 in a region between an origin 383 of radius 386 and an end point 392 of tool 380. The angle θ of the chisel point may be 20° as measured from a vertical edge of tool 380. By offsetting the beginning of chisel point 390 lower than the origin 383 of radius 386, mating members (or tabs) 256 (see FIG. 22B) are formed as tool 380 penetrates the side wall of header 206, 208. The function of mating member (or tabs) 256 has been thoroughly discussed in the prior portions of this disclosure.
Although matching the radius R of tool 380 to the inner diameter R of header 206, 208 is generally considered to be the preferred method of creating tabs 256, 258 in header 206, 208, other tool geometries may be useful. For example, FIG. 23A is a front elevational view of a tool that has a generally rectangular body 396 and has a piercing portion 398 that when viewed from the front elevational view includes side portions having a concave profile 400, 402. In another embodiment (see FIGS. 24A and 24B), a tool 404 is formed having a generally rectangular body portion 406 and a piercing portion 408 that when viewed from a front elevational view has tapering sides 410, 412 that taper generally linearly.
If pressurized fluid is used during the piercing operation, the side walls of header 206, 208 which are first contacted by the leading edge of tool 380 do not distort inwardly to the extent that they would if pressurized fluid was not present within the inner cavity of the header tube 206, 208. This minimal distortion can be seen by comparing the depiction in FIG. 25 (showing the distortion which is generally characteristic of a hydropierce operation) to the depiction of FIG. 25 (which shows the distortion typically associated with a piercing operation where no pressurized fluid is used). When pierce operations are carried out without the use of pressurized fluid within the tubular member, it is commonly referred to as an “air dye” operation. In contrast, piercing operations which are carried out using a pressurized fluid to pressurize the inner chamber of a work piece are known as hydropierce operations. The method of forming tabs 256 as disclosed herein can be accomplished using either hydropiercing or air dye operations. The bell mouth distortion 414 (see FIG. 27) typically left behind after a hydropierce operation or an air dye operation, can provide a good mating surface for braze soldering a tube within the bell mouth opening 416 or, the opening 416 may be threaded for accepting a threaded fastener (see FIG. 28).
Although using a single tool 380 may be used to create tube slots one-by-one or baffle slots one-by-one, it is envisioned that in a production environment, much faster processing times must be achieved. Accordingly, the methods and apparatus of the present invention are effective for mass producing heat exchanger headers by using the processes discussed below.
Individual piercing tools 380 are assembled into a group of piercing tools 420. Multiple piercing tools 420 are all rigidly retained within tool base 418. Now referring to FIGS. 30 and 31, tool base 418 supports multiple piercing tools 420. Tool base is attached to platen 422. Platen 422 is capable of reciprocating upwardly and downwardly 428 by way of reciprocating drive 430. One or more stripper springs 426 connect stripper rail 424 to tool base 418. Stripper rail 424 has a plurality of openings (exemplified at 427 in FIG. 30) that pass through stripper rail 424 wherein each opening 427 cooperates with a respectively associated pierced tool 380 in the plurality of pierce tools 420. Base 432 supports reservoir 434 which contains a non-compressible fluid (such as water, oil or the like). Reservoir 434 supports cradle 436 which is generally formed to conformingly support a portion of an outer surface of work piece 438. Cradle 436 is flanked by one or more plunger assemblies 440, 442. The function of plunger assemblies 440, 442 will be explained more fully in conjunction with FIG. 36 through FIG. 39. Although only one plunger assembly 440, 442 is necessary to carry out hydropierce operations, it might be advantageous to use a second plunger assembly 442 in some applications. Because both plunger assemblies 440 and 442 work in an identical manner, only one of them will be discussed hereinafter. Each plunger assembly 440, 442 may be furnished with a pressure relief valve 444, 446 for relieving an overpressure condition that might develop. The function of pressure relief valve 444, 446 will be discussed in greater detail in conjunction with FIG. 36 through FIG. 39. A bottom portion 447 of stripper rail 424 is formed 448 to conform to an outside surface of work piece 438. Likewise, upper surface 449 of cradle 436 includes a portion 450 which is generally formed to conform to an outer surface of work piece 438. Contour 448 and 450 ensure that work piece 438 does not move once the multiple pierce tools 420 begin their piercing operation.
Now referring to FIGS. 32 and 33, once work piece 438 has been deposited into lower contour of cradle 436, reciprocating drive 430 is activated thereby lowering platen 422 which in turn lowers the entire pierce tool assembly 454. Stripper rail 424 is the first component of pierce tool assembly 454 to contact cradle 436. Thereafter, as pierce tool assembly 454 continues its downward ascent, stripper spring 426 begins to compress thereby allowing the platen to continue its downward descent which drives each pierce tool 380 toward work piece 438.
Now referring to FIGS. 34, 35 and 36, at the point where piercing portion 384 of tool 380 begins to carry out its piercing operation, the position of the operative components are generally shown in FIGS. 34 and 35. Drive arms 456, 458 are carried by platen 422. The function of drive arms 456, 458 is to activate a respectively associated plunger assembly 440, 442 to hydraulically pressurize an inner chamber 426 of work piece 438. Because the operation of each plunger assembly 440, 442 is identical, only plunger assembly 440 will be discussed hereinafter. Everything that is described herein relating to plunger assembly 440 and its associated drive arm 456 directly applies to plunger assembly 442 and its respective drive arm 458.
Plunger assembly 440 may include, in an embodiment, slide block 460, plunger 462, plunger return spring 464, and guide block 466 (see FIG. 36). Drive arm 456 includes canted work surface 457 and sliding block 460 includes canted work surface 459 (see FIG. 32). Sliding block 460 is adapted to slide in a horizontal motion. Thus, when drive arm 456 moves downwardly such that canted work surfaces 457, and 459 contact one another, any further downward motion of drive arm 456 causes slide block 460 to move in a horizontal 468 direction. When slide block 460 moves in a horizontal direction, plunger 462 moves into engagement with the end opening 470 of work piece 438. When plunger 462 contacts an opening 470 of work piece 438, it traps hydraulic fluid within inner chamber 438 of work piece. Thereafter, any further horizontal movement of plunger 462 will pressurize the fluid within inner chamber 246 of work piece 438. This pressurized fluid minimizes the collapse of the sidewalls of work piece 438 during the hydropiercing operation (as has already been discussed in conjunction with FIGS. 25 and 26). In order to limit the magnitude of the hydraulic pressure developed within inner chamber 426 of work piece 438, pressure relief valve 444 is provided in hydraulic communication 466 with the fluid pressure within inner chamber 438. Preferably, pressure relief valve 444 is the type of pressure relief valve which is field adjustable so that the optimum internal pressure can be set once all operating conditions and tolerances are in play.
Now referring to FIGS. 37, 38 and 39, when platen 422 is at the lower most portion of its downstroke, the configuration of the component parts are generally as depicted in FIGS. 37, 38 and 39. FIG. 38 depicts tool 380 at the lower most portion of its downstroke wherein tabs 256 are formed in the side walls of work piece 438 in an identical manner to that which has already been described in conjunction with FIGS. 22A, 21 and 22B. Also, when platen 422 is at the lower most portion of its downstroke, sliding block 460 is at the left most extreme portion of its stroke (as depicted in FIG. 39, this means that block 460 has traveled to its maximum, left most extent). In turn, plunger 462 is shown at its left most travel extent.
Plunger 462 may include fluid communication channel 472 and guide block 466 may include fluid communication channel 474. If at least one of the fluid communication channels 472, 474 includes a channel slot 476 which is generally oriented parallel to the movement 468 of plunger 462, pressure relieve valve 444 can monitor the pressure developed within inner chamber 246 of work piece 438 irrespective of where plunger 462 is in its stroke. In the embodiment shown in FIG. 39, guide block 466 is fashioned with channel slot 476. Channel 476 is generally parallel to the direction 468 of the plunger stroke. One skilled in the art will readily recognize that channel slot 476 can just as easily be formed in plunger 462 and still accomplish the function of allowing pressure relief valve 444 to be uninterrupted fluid communication with the pressure developed within inner chamber 246 of work piece 238 during the piercing operation.
Now referring to FIG. 40, in another embodiment of the piercing apparatus of the present invention, one or more lower pierce tools 478 can be added to the pierce tool apparatus to compliment the upper pierce tools 380 that have already been discussed. Lower pierce tools 478 are mechanically, hydraulically, electrically or the like connected 482 to a pierce tool driver mechanism 480. Pierce tool driver mechanism 480 is synchronized to the controls which otherwise operate the entire pierce tool apparatus in a way that allows the pierce tool driver 480 to raise one or more lower pierce tools 478 at the appropriate time so that bottom slots can be placed in workpiece 238 simultaneously, or generally simultaneously, with the placement of upper slots in workpiece 238 by one or more upper pierce tools 380.
It is to be understood that the invention sought to be afforded protection hereby is not limited to the exact construction or embodiments illustrated and described herein, but that various changes and modification may be made without departing from the spirit and scope of the invention as defined in the following claims.