US3457749A

US3457749A - Flexible tube forming machine

Info

Publication number: US3457749A
Application number: US556075A
Authority: US
Inventors: Carl W Smola
Original assignee: Versatube Corp
Current assignee: Versatube Corp
Priority date: 1966-06-08
Filing date: 1966-06-08
Publication date: 1969-07-29
Anticipated expiration: 1986-07-29

Description

July 29, 1969 c. w. SMOLA 3,457,749

1 FLEXIBLE TUBE FORMING MACHINE Filed June 8, 1966 2 Sheets-Sheet 1 FIGS FlGZ) INVENTOR CARL 1/24 SMOLA ATTORNEYS y 1969 c. w. SMOLA 3,457,749

FLEXIBLE TUBE FORMING MACHINE Filed June 8, 1966 2 Sheets-Sheet FIG. 9

INVENTOR CARL W SMOL A- ATTORNEYS United States Patent 3,457,749 FLEXIBLE TUBE FORMING MACIHNE Carl W. Smola, Detroit, Mich, assignor to Versatube C0rp., Detroit, Mich, a corporation of Michigan Filed June 8, 1966, Ser. No. 556,075 Int. Cl. B210 37/12; 1321f 3/04 U.S. Cl. 7250 3 Claims ABSTRACT (IF THE DISCLOSURE This invention relates to machines for forming hollow tubing and more particularly to a machine for producing an improved, sealed flexible tubing spirally wound from a continuous strip of metal.

Flexible tubing of the character to which the machine of the present invention relates is adapted to a wide variety of uses such as exhaust tubing for automotive and aircraft vehicles, conduits for electrical wiring, heating and cooling coils and the like.

The properties that are most desirable in tubing of this type is that it be flexible under severe service while maintaining fluid or gas tight characteristics. It is the broad purpose of the present invention to provide tube forming apparatus adapted to develop a flexible tubing which will maintain its sealed, fluid tight properties under the severest of service.

conventionally, flexible tubing is produced by feeding a continuous flat strip of a suitable material through successive pairs of profiling rolls. The profiling rolls countour the strip so that it emerges from the final pair of rolls with a generally S-shaped cross-section having actutely bent oppositely turned flanges. The flanged strip is then delivered tangentially to the peripheral edge of an elongated rotating mandrel. A die cooperates with the mandrel to coil the flanged strip around the mandrel such that flanges of the adjacent edges of the strip are brought into engagement. A pressure roll then exerts a force on the engaged flanges to cause them to collapse against the mandrel such that the inner surface of the produced tubing assumes the configuration of the circumferential surface of the mandrel.

It is the broad purpose of the present invention to improve the fluid tight characteristics of spirally wound flexible tubing by providing a set of profiling rolls having peripheral edges which are adapted to take the strip, between them and which cooperates to form a longitudinal groove adjacent one edge of the strip. Preferably the groove is formed prior to the flanging steps and is provided in the portion of the strip forming one of the flanges.

A strip of sealing material is inserted in the groove subsequent to the profiling operation, but prior to the coiling step. The sealing material is chosen to suit the purpose for which the finished tubing is to be utilized, but for purposes of description may be a copper or bronze wire or an asbestos thread.

During the coiling step, the pressure rolls collapse the flanges against the mandrel such that the sealing strip is tightly contained between the grooved flange and the body of the strip. Thus the improved tubing retains its sealed shape even as the flanges are worked against one ice another such as when subjected to severe and continuous vibrations.

Another feature of the improved tube forming machine, takes the form of a die shoe which is provided with a pair of parallel slots running in the direction of the moving strip and which positively contains the flanged strip against lateral movement as it assumes a coiled shape around the rotating mandrel. The double slotted die cooperates with the mandrel to ensure that the flanged convolutions of the strip are fully engaged and prevent twisting of the strip that may result in the flanges slipping out of engagement before they have been securely interlocked by the pressure rolls.

It is therefore an object of the present invention to provide spiral tube making machines adapted to produce an improved fluid tight flexible tubing by providing a pair of profiling rolls which cooperate to form a longitudinal groove in the strip forming the tube and which groove is adapted to retain a sealing material in the finished tubing.

It is another object of the present invention to improve flexible spiral tube forming machines by providing a die associated with a rotating mandrel having a pair of parallel slots running in the direction of the advancing flanged strip and which slots prevent lateral movement of the strip as the flanges of adjacent coiled strips are engaging one another.

Other objects, advantages and applications of the present invention will become apparent to one skilled in the art to which the invention pertains upon reference to the following detailed description of the preferred embodiment of the invention and to the accompanying drawings in which like reference characters refer to like parts throughout the several views, and in which:

FIGURE 1 is a schematic elevational view of a hollow tube forming machine illustrating a preferred embodiment of the present invent-ion;

FIGURE 2 is a sectional view taken through a first pair of profile rolls illustrated in FIGURE 1 and as seen from line 2-2 of FIGURE 1;

FIGURE 3 is a fragmentary sectional view as seen from line 3-3 of FIGURE 1;

FIGURE 4 is a fragmentary view as seen from line 4-4 of FIGURE 1;

FIGURE 5 is a fragmentary view as seen from line 5-5 of FIGURE 1;

FIGURE 6 is a sectional view of a strip guide trough as seen from line 6-6 of FIGURE 1;

FIGURE 7 is a schematic plan view of the preferred tube forming machine illustrated in FIGURE 1;

FIGURE 8 is a sectional view of the die and mandrel as seen from line 8-8 of FIGURE 1;

And FIGURE 9 is a view of a preferred locking configuration for a mandrel and its associated drive shaft.

Referring to FIGURES l and 7 a preferred spiral tube making machine comprises a motor 10 drivingly connected to a profiling assembly generally indicated at 12 and a coiling assembly generally indicated at 14 all of which are mounted on a base member 16.

The profiling assembly 12 preferably comprises four pairs of aligned

profiling rolls

18, 20 and 22 and 24 rotatably mounted in a gear box 26 which is fixed to the upper surface of the base 16. The motor 10 has output through a sprocket assembly 28 to a gear box 30 which is operatively coupled with the input of a gear box 26 through the coupling.

The

profiling rolls

18, 20, 22, and 24 are preferably mounted to the gear box 30 such that a continuous strip 32 of a suitable metallic tube forming material such as aluminum, stainless steel, or the like is advanced successively through each pair of profiling rolls in a linear path. The strip 32 first passes between the profile rolls 18 each of which has a peripheral surface which mate with one another as can be seen in FIGURE 2 to form a longitudinal grooved section indicated at 34 and which preferably formed adjacent one edge of the strip 32.

The strip 32 then is delivered from the profile rolls 18 to the second pair of profile rolls 20 which as can be seen in FIGURE 3 have mating peripheral surfaces which cooperate to form a stepped contour or shape 36 in the strip 32 approximately intermediate the side edges of the strip 32. Preferably the half of the strip containing the groove 34 is stepped such that the groove faces away from the other or non-grooved half.

The strip 32 is delivered from the profile rolls 20 to the profile rolls 22 which as can be seen in FIGURE 4 have mating peripheral surfaces adapted to form oppositely extending flanges 38 and 40 in the strip 32. The flanges 38 and 40 are formed in opposite sides and extend normally to the body of the strip in opposite directions. The strip 32 then passes from the profile rolls 22 and is delivered to the last set of profile rolls 24 which cooperate to bend the flanges 38 and 49 inwardly approximately 20 to 30 with respect to the body of the strip as can be seen in FIGURE 5. Thus it can be seen that the profile assembly shapes the flat strip of metal 32 into a generally S-shaped cross-section having a groove in one of the flanges.

The profiled strip 32 then passes from the profiling assembly 12 to an elongated enclosed guide trough 42 which delivers the contoured strip 32 tangentially to the surface to an elongated mandrel 44 rotatably mounted on a frame 46 fixed to the upper surface of base 16. The strip 32 is delivered at an oblique angle with respect to the axis of the mandrel 44. The guide trough 42, as can be seen in FIGURE 1, is carried by a right angle bracket 47 which is fixed to the frame 46. As can be seen in FIGURE 6 a cross-section to the feed trough 42 shows that it has a shaped passage adapted to conform to the generally S-shaped contour of the strip 32.

Intermediate the inlet of the trough 42 and the last set of profile rolls 24, a flexible packing 48 is delivered from a spool (not shown) to the moving flanged strip 32 and fitted into the channel section 34 at a point immediately adjacent the inlet of the feed trough 42 as can be seen in FIGURES 1 and 6.

The rotary mandrel 44 is carried by a drive shaft 50 which is journalled in the frame 46 and driven by a gear set 52 (FIGURE 7) which is operatively connected by sprocket set 54 to the output shaft 55 of reduction gear box 30.

It is to be understood that the peripheral surface of the rotary mandrel 44 may take any desired configuration but for purposes of the description is shown with a cylindrical surface. It is to be further understood that the diameter of the mandrel is chosen according to the size of the tubing that is desired. The mandrel 44 is connected to the drive shaft 50, as can be seen in FIGURE 9, and the drive shaft 50 has an axial concentric bore 56 formed on its driving end which carries a transversely extending finger 58 spaced from the open end thereof. The mandrel 44 has a narrowed end which is complementarily shaped to the bore 56 and has substantially the same length as the depth of the bore. A longitudinal slot 62 is formed in the end of the narrowed portion a distance equal to the spacing of the finger 58 from the dead end of the 'bore 56. The slot 62 terminates at a short transversely formed slot 64. Thus the Lmandrel 44 is engaged with the drive shaft 50 by inserting the narrowed end within the bore 56 so that the finger 58 is received by the slot 62, moving the mandrel 44 toward the drive shaft 50 and then rotating the two such that they become locked together as the finger 58 moves within the slot 64.

Three bearing blocks 66, 68, and 70 (FIGURE 7) are carried by the frame 46 preferably equiangularly about a short shaft 76. A roller 78 is rotatably carried by each' of the shafts 76.

The shafts 76 are each connected by a universal joint 79 (FIGURE 7) to a link 80 which is rotatably driven by gear set 52 such that the rollers 78 have a peripheral surface speed conforming to the surface speed of the rotary mandrel 44.

The strip 32 is delivered between the mandrel 44 and the first driven roller 78 such that it is introduced to a die 82 as can best be seen in FIGURES 1 and 8. The die 82 is adjustably carried by the frame 46 and has a working surface 84 spaced from the rotating circumferential surface of the mandrel slightly greater than the thickness to the strip 32. A pair of parallel slots 86 and 88 project normally inward from the surface 84 to a depth approximately equal to the developed thickness of flanges 38 and 40 and are disposed in the path of the advancing flanged strip 32. The die cooperates with the mandrel to wind the strip 32 spirally on the mandrel such that the trailing flange edge 38 engages with the leading flanged edge 40 in the die 82. The engaged flanged edges advance to the second and third rollers 78 which apply a force suflicient to collapse the flanges against the mandrel. The collapsed flanges thus are interlocked together. Referring to FIGURE 8, the sealing strip 48 is trapped in the groove 34 by the body of the strip such that it forms a sealing engagement between adjacent coils. The sealing strip thus permits the interlocked flanges to move relative to one another so that the produced tube may be bent into any desirable shape while ensuring that the tube retains its fluid tight properties.

As the spiral tube develops, it moves progressively away from the die 82 and the driven rolls 78 as can be seen in FIGURE 7 where it may be delivered to a suitable pick-up or coiling means (not shown).

In summary I have described an improved spiral tube forming machine including a pair of profiling rollers adapted to provide a longitudinal running groove adjacent one end of the uncoiled tube forming strip stock. The groove is adapted to seat a packing or sealing strip which is locked in the groove during the spiral forming process. The locked sealing strip ensures a fluid tight flexible tubing under extreme working conditions.

Furthermore, I have described an improved coil forming die adapted to positively retain adjacent sections of the flanged strip as they engage one another and then advance to a pressure roll wherein they are interlocked.

Although I have described but one preferred embodiment of my invention, it will be apparent to one skilled in the art to which the invention pertains that various changes and modifications may be made therein without departing from the spirit of the invention as expressed in the scope of the appended claims.

What is claimed is:

1. Apparatus for forming a thin flat strip of continuously fed material into a continuous closed spirally wound tubing, comprising:

(a) a frame;

(b) means for bending the edges of the strip material to form flanges extending in opposite directions from the body of the strip, said means comprising a plurality of pairs of rolls disposed with their axes parallel to one another and rotatably supported with respect to the frame so that said strip may successively .pass through said rolls, the first of the pair of rolls through which said strip is passed having such a configuration as to form a groove adjacent to one end of the strip and the successive rolls being operative to form said flanges, with said groove being disposed at the extremity of and on the outwardly facing surfaces of one of said flanges;

(c) means for introducing a strip of sealing material into said groove;

(d) a mandrel rotatably mounted on said frame;

(e) means for rotating said mandrel;

(f) means for advancing the flanged strip material tangentially to said rotating mandrel and in a direction oblique to the axis of the mandrel while maintaining said sealing strip Wihtin said groove;

(g) a die fixed to said frame and presenting a working surface closely adjacent the circumferential surface of said mandrel, and said die effective to produce a helical form to the strip to assist in coiling it in helical convolutions on the rotating mandrel and with said slots cooperating to engage the flanges of adjacent convolutions; and

(h) roll means disposed in the path of the advancing engaged flanges and operable to sealingly collapse said flanges against the body of said strip material with the surface of the flange containing said groove being collapsed against the body of said strip material whereby said sealing strip is pressed directly against said body of said strip material to produce a seal between said flange and the body of said strip material.

2. The invention as defined in claim 1, wherein said last mentioned means comprise:

(a) a plurality of rolls connected to said frame for adjustable movement toward and away from the longitudinal axis of said rotating mandrel, said rolls disposed in the path of the engaged flanged strips;

(b) means for rotating said rolls in timed relationship to said rotating mandrel; and

(c) said rolls having a smooth peripheral surface for collapsing said engaged flanges into interlocking relationship.

3. The invention as defined in claim 2, wherein said slotted die is disposed to receive said advancing strip substantially at the point of tangency between the advancing strip and the surface of the mandrel.

References Cited UNITED STATES PATENTS 1,580,760 4/1926 Palmer 72-50 2,595,747 5/1952 Anderson 7250 2,686,487 8/1954 Carr 725O CHARLES W. LANHAM, Primary Examiner ANDREW L. HAVIS, Assistant Examiner US. Cl. X.R. 72142