TUBE FORMING MACHINE
A machine or device for forming tubes or the like includes one or more cables or other elongated flexible members. An expanding forming device is positioned at an end of the cables, and the cables are inserted into a tube that is to be formed. The expanding device expands outwardly, and tension is placed on the cables to pull the cables through the tubes. This causes the tubes to be permanently deformed outwardly to a larger outer diameter.
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This application claims the benefit of U.S. Provisional Application No. 61/589,021 filed on Jan. 20, 2012, entitled, TUBE FORMING MACHINE, the entire contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTIONMetal tubing is commonly used in a variety of components or devices such as heat exchangers and the like. During assembly of a heat exchanger, the tubing may be inserted into openings in a plurality of spaced-apart thin metal sheets forming fins. The openings in the fins typically have a diameter that is slightly greater than the outside diameter of the tubing to facilitate assembly of the tubes with the fins. The tubing is then expanded to form a tight interference fit between the tubing and the fins.
Machines have been developed to expand and permanently deform metal tubing. For example, the tube may be expanded by pushing a ball or other forming tool into the open end of the tubing. The ball has an outer diameter that is equal to the desired final inner diameter of the expanded portion of the tube. The final inner diameter is chosen to provide a tube outer diameter that will provide an interference fit. In this type of operation, the ball or other expanding/forming tool component is mounted on a rigid rod or the like, and the ball is pushed into the open end of the metal tubing while the metal tubing is held in place. This operation thereby puts the metal rod and the tubing into compression.
BRIEF SUMMARY OF THE INVENTIONOne aspect of the present invention is a machine and method for forming metal tubing or the like. The machine includes one or more elongated flexible members (e.g. cables) that are wound onto drums. Expanding forming tools such as a mandrel and expanding collet are located on an end of each cable. The expanding forming tools are inserted into open ends of the metal tubes that are to be expanded. The cables unwind from the drums until the expanding end tools (e.g. expanding collets) are at their desired final position. The collets are then expanded by pulling on the cables to shift the mandrels relative to the expanding collets. Outer sleeves of the cables transmit forces pushing on the expanding collets in a direction opposite the pulling forces acting on the mandrels. The expanded collets are then pulled through the tubes utilizing the cables. The cables are wound back onto the drums as the expanded forming tools are pulled through the tubes.
For purposes of description herein, the terms “upper,” “lower,” “right,” “left,” “rear,” “front,” “vertical,” “horizontal,” and derivatives thereof shall relate to the invention as oriented in
With reference to
First end portions 13 (
End portions 20 of cables 14 (
With further reference to
Mandrel 50 may be threadably connected to a fitting 52 that is secured to cable 36. In this way, the mandrel 50 and collet 38 can be changed if the mandrel 35 and/or collet 38 become worn or damaged, or if a different size mandrel 35 and collet 38 is required for a particular application.
It will be understood that the cables, mandrels, and expanding collets are simply examples of elongated flexible members and expanding tools that may be utilized according to the present invention. Various elongated members such as chains, a long single strand of flexible matter or the like may also be utilized. Virtually any elongated tension member that can be curved for binding on a drum or the like could be used. Also, various expanding forming tools could be utilized, and the mandrel and expanding collet described herein are simply an example of a suitable expanding forming tool. Also, it will be understood that in situations wherein the tubes to be formed have first and second opposite open ends, the forming tool could comprise a separate tool that is connected to an end of an elongated flexible member after the elongated flexible member is inserted into the first end of the tube such that the end of the flexible member protrudes from the second end of the tube. In this way, a fixed size (non-expanding) forming tool may be utilized with elongated cables and drums or the like according to other aspects of the present invention.
A tension arm 55 (
During operation, rotation of main shaft 7 causes tension arm 55 to rotate at the same rate as shaft 7. However, drum 6 only rotates if tension arm 55 is in contact with either of the plates 57. Initial movement of arm 55 (without rotation of drum 6) shifts the mandrel 50 relative to expanding collet 38 to thereby expand or contract collet 38. Upon further rotation, the arm 55 contacts one of the plates 57, thereby causing both the cable 36 and the outer sleeve 37 to move at the same rate.
A heat exchanger 66 (
Heat exchanger 66 is then positioned adjacent the ends 34 of cables 14. Heat exchanger 66 may be held in place manually or it may be secured to a support surface or fixture (not shown) adjacent the machine 1. Machine 1 is then actuated, and drums 6 and feed rollers 26A and 26B move the ends 34 of cables 14 into the open ends 65 of tubes 16 and 17.
After the ends 34 of cables 14 are fully inserted into the tubes 16 and 17 (i.e. the ends 34 are positioned beyond the outermost fin 67), tension arm 55 is rotated relative to the drum body 59 to thereby tension cable 36. This pulls mandrel 50 into expanding collet 38, thereby causing the curved forming surfaces 51 of collets 38 to expand outwardly. Outward expansion of collet 38 generates an outward force on tubes 16 and 17, thereby expanding the diameter of the tubes 16 and 17. The tubes 16 and 17 are made of copper or other formable metal, such that expansion of collet 38 permanently deforms the tubes 16 and 17.
After the collets 38 are expanded due to movement of tension arm 55 relative to drum body 59, the drums 6 are rotated to pull the ends 34 through the tubes 16 and 17 in the direction of the arrow “S” (
The size of the collets 38 and mandrel 35 are selected to permanently expand the outer diameters of tubes 16 and 17 sufficiently to create an interference fit between the tubes 16 and 17 and openings 68 in fins 67. In general, the tubes 16 and 17 are deformed both elastically (i.e. temporarily) and plastically (i.e. permanently), such that the diameter of the tubes 16 and 17 is typically reduced slightly after the collets 38 pass through the tubing 16 and 17. Thus, the expanded diameter of the collets 38 may be slightly larger than the final desired inner diameter of the tube 16 and 17 to account for the elastic contraction of tubes 16 and 17.
After the expanding collets 38 are pulled out of the open ends 65 of tubes 16 and 17, the fittings 41 contact a travel plate 75, thereby shifting the tension arm 55 relative to drum body 59. This causes a compressive force to be applied to cable 36 to push the mandrels 35 out of the collets 38. This causes the collets 38 to shrink in diameter for insertion into the tubes of the next heat exchanger 66 to be formed.
Because the cables 14 wind onto drums 6, the forming machine 1 has a compact overall size that is much smaller than that of rigid pushrod type forming machines. The machine 1 may be utilized to form tubing of different lengths by adjusting the length of cable 14 that is unwound from drums 6. Also, mandrels and/or collets of different sizes may be utilized to form tubing of various sizes as required for a particular application.
With further reference to
With further reference to
In use, forming tool 110 is detached from end 80 of cable 82, and end 80 of cable 82 is inserted into an open end 65 (
With further reference to
Tube forming machine 155 includes a guide roller 188 (
A plurality of guide tubes 202 are mounted to support structure 156 by brackets 204 and support blocks 206. Guide tubes 202 include a flared outer end 208 that is positioned adjacent a guide block 210. The guide block 210 supports the expandable forming tubes 34A as they are inserted into the open ends 182 of tubes 184. The guide tubes 202 support the cables 82 and prevents collapse of the cables 82 as the forming tools 34A are driven into the tubes 184.
In use, the heat exchanger tubes and fins 184 are positioned on a fixture 212 (
Controller 216 then actuates drive assemblies 158 and 198 to thereby cause the cables 82 to wind onto drums 170. As cables 82 are retracted, frictional contact between surfaces 151 of collet 88 and tubes 184 causes collet 88 to shift in a direction opposite the arrow A (
As the drums 170 continue to rotate, the collets 88 are eventually pulled out of the open ends 65 of tubes 184. The heat exchanger can then be removed and new tubes 185 and fins 186 can then be positioned on fixture 212, and the forming tools 34A can then be inserted into the open ends 182 of tubes 184 to repeat the forming operation.
The present invention is not limited to the specific example described above. For example, various mechanisms and devices may be utilized to pull on the cables, and to provide an expanding portion that is pulled through the tubes. Also, various types of elongated flexible members could be utilized in place of the cable arrangement described above, and other expanding and retracting forming devices or tools could be utilized in place of the mandrel and expanding collet described above. Still further, although a circular drum is preferred for winding the cable, other storage devices and arrangements could be utilized to provide for storage of an elongated flexible unit in a relatively compact manner.
It is to be understood that variations and modifications can be made on the aforementioned structure without departing from the concepts of the present invention, and further it is to be understood that such concepts are intended to be covered by the following claims unless these claims by their language expressly state otherwise.
Claims
1. A tube forming apparatus, comprising:
- a support structure;
- a winding member rotatably mounted to the support structure;
- at least one elongated flexible member that winds onto the winding member, the elongated flexible member having an end that moves towards the winding member upon rotation of the winding member;
- a powered actuator operably connected to the winding member such that actuation of the powered actuator causes the winding member to rotate and wind the at least one elongated flexible member onto the winding member;
- an expandable forming tool connected to the end of the at least one elongated flexible member, the expandable forming tool having outer forming surfaces that can be selectively shifted outwardly from an insertion configuration to a forming configuration, and wherein:
- the end of the elongated flexible member and the expandable forming tool can be inserted into an elongated metal tube in the insertion configuration, followed by shifting the outer forming surfaces outwardly, followed by actuation of the powered actuator to rotate the winding member to pull the expandable forming tool back through the metal tube, such that the tube is deformed outwardly due to contact between the outer forming surfaces of the expandable forming tool and inner surfaces of the tube.
2. The tube forming apparatus of claim 1, wherein:
- the expandable forming tool comprises an outer member, wherein the outer forming surfaces are disposed on the outer member; and wherein:
- the expandable forming tool further comprises an inner member at least partially disposed in the outer member, and wherein the inner member is configured to engage the outer member and shift the outer forming surfaces outwardly.
3. The tube forming apparatus of claim 2, wherein:
- the outer member includes a plurality of flexible fingers, wherein the outer forming surfaces are disposed on the fingers.
4. The tube forming apparatus of claim 3, wherein:
- the outer member includes a base portion, and the fingers extend from the base portion.
5. The tube forming apparatus of claim 2, wherein:
- the inner member comprises a mandrel having an inner end and an outer end that is enlarged relative to the inner end, the inner member further comprising a tapered transition portion extending between the inner end and the outer end.
6. The tube forming apparatus of claim 5, wherein:
- the tapered transition portion has a generally conical outer surface.
7. The tube forming apparatus of claim 6, wherein:
- the outer member includes inner surface portions that engage the conical outer surface of the inner member.
8. The tube forming apparatus of claim 7, wherein:
- the inner surface portions of the outer member are generally conical and slidably engage the generally conical outer surface of the inner member as the inner member is shifted axially relative to the outer member.
9. The tube forming apparatus of claim 2, wherein:
- the outer member defines a bore extending axially through the outer member;
- the inner member is movably disposed in the bore, the inner member including a tapered outer surface that engages the outer member and moves the outer forming surfaces outwardly upon shifting of the outer member relative to the inner member in a first direction; and including:
- a resilient member biasing the outer member in the first direction relative to the inner member.
10. The tube forming apparatus of claim 1, wherein:
- the elongated flexible member comprises a cable.
11. The tube forming apparatus of claim 10, wherein:
- the cable includes an inner strand and an outer casing, wherein the inner strand is movably disposed in the outer casing; and wherein:
- the inner strand and the outer casing are operably connected to the expandable forming tool such that shifting of the inner strand relative to the outer sheath causes the outer forming surfaces of the expandable forming tool to shift outwardly.
12. The tube forming apparatus of claim 11, wherein:
- the winding member comprises a pulley disposed on the shaft for rotation relative to the shaft; and including:
- a shaft rotatably mounted to the support structure;
- a lost motion device including a tensioning member that is fixed to the shaft, wherein the tensioning member permits rotation of the winding member in first and second opposite directions relative to the shaft for a predefined rotational distance, after which the pulley rotates with the shaft; and wherein:
- the tensioning member is connected to the inner strand and the outer casing is connected to the pulley such that rotation of the pulley relative to the shaft shifts the inner strand relative to the outer casing to thereby selectively shift the outer forming surfaces inwardly and outwardly.
13. The tube forming apparatus of claims 12, wherein:
- the pulley includes spaced apart stop surfaces;
- the tensioning member comprises a tension arm disposed between the stop surfaces and defining a gap relative to at least one of the stop surfaces.
14. A tube forming apparatus, comprising:
- at least one elongated flexible member;
- a powered device operably connected to the elongated flexible member, wherein the powered device includes a pull member that is operably connected to the elongated flexible member and a powered actuator that is operably connected to the pull member such that actuation of the powered actuator causes the pull member to pull on the elongated flexible member; and
- a forming tool connected to the elongated flexible member, the forming tool having outer forming surfaces configured to slidably engage an inner surface of a side wall of a tube to thereby expand the tube outwardly to increase an outer dimension of a tube as the forming tool is pulled through the tube.
15. The tube forming apparatus of claim 14, wherein:
- the outer forming surfaces of the forming tool can be shifted outwardly to increase a size of the forming tool.
16. The tube forming apparatus of claim 15, wherein:
- the forming tool includes an outer member having a bore therethrough, and an inner member movably disposed in the bore, the inner member having an engagement surface that engages the outer member upon movement of the inner member relative to the outer member to shift the outer forming surfaces outwardly, and wherein the inner member is connected to the elongated flexible member such that tension on the elongated flexible member causes the inner member to shift relative to the outer member and thereby shift the outer forming surfaces outwardly.
17. The tube forming apparatus of claim 14, wherein:
- the pull member comprises a pulley, and the powered actuator comprises an electric motor that rotates the pulley and causes the elongated flexible member to wind onto the pulley.
18. The tube forming apparatus of claim 14, wherein:
- the elongated flexible member defines an end;
- the forming tool is detachable connected to the end of the elongated flexible member, the forming tool comprising a rigid, non-expandable member having smoothly curved outer forming surfaces.
19. The tube forming apparatus of claim 18, wherein:
- the outer forming surfaces are approximately spherical.
20. A method of expanding a tube, the method comprising:
- providing an elongated metal tube having an open end and inner and outer surfaces defining inner and outer diameters, respectively;
- providing a powered machine including a powered actuator and an elongated flexible member that can be pulled upon actuator of the powered actuator, the powered machine including an expandable forming tool connected to the elongated flexible member, the expandable forming tool having outer forming surfaces that can be shifted outwardly from a first configuration to a second configuration;
- inserting the expandable forming tool into the open end of the elongated metal tube;
- pushing the elongated flexible member to move the expandable forming tool in the tube in a first direction;
- causing the expandable forming tool to shift from the first configuration to the second configuration, wherein the outer forming surfaces define an outer dimension that is transverse to a length of the tube, and wherein the outer dimension is greater than the inner diameter of the tube;
- deforming the elongated metal tube to increase the diameter of the elongated metal tube by pulling the expandable forming tool back through the elongated metal tube in a second direction that is substantially opposite the first direction with the outer forming surfaces pushing outwardly on the inner surface of the elongated metal tube.
21. The method of claim 20, wherein:
- the outer forming surfaces slidably engage the inner surface of the elongated metal tube as the expandable forming tool is pulled in the second direction.
22. The method of claim 20, wherein:
- the elongated metal tube has a hairpin shape and includes a pair of generally parallel linear sections that are joined by a curved portion; and including:
- providing a plurality of plate members, each having at least two openings therethrough;
- positioning the elongated tube such that the linear sections extend through the two openings prior to pulling the expandable forming tool through the tube in the second direction.
23. The method of claim 20, wherein:
- the expandable forming tool includes an outer member and an inner member that movably engages the outer member; and including:
- shifting the inner member relative to the outer member to thereby shift the outer forming surfaces from the first configuration to the second configuration.
24. The method of claim 20, wherein:
- the elongated metal tube is substantially linear with opposite ends that are open; and including:
- providing a plurality of plate members, each having at least one opening therethrough;
- positioning the elongated metal tube in the openings prior to pulling the expandable forming tool back through the elongated metal tube in the second direction.
Type: Application
Filed: Jan 21, 2013
Publication Date: Jul 25, 2013
Applicant: KAYDON CORPORATION (Ann Arbor, MI)
Inventor: Kaydon Corporation (Ann Arbor, MI)
Application Number: 13/746,010
International Classification: B21D 41/02 (20060101);