Tube corrugating apparatus and method
United States Patent 1191 Thompson 1 Apr. 22, 1975 TUBE CORRUGATING APPARATUS AND 2.603.680 7/1952 Snyder 29/520 METHOD 2.756.804 7/1956 Schindler.... 72/59 2.987.798 6/1961 Fr0mont..... 72/370 Inventor: Tom ps Milford Mich- 3,247,694 4/1966 Honfeldt ct al. 72 59 [73] Assignees: Robert C. Hauke, Holly; Claude A. FOREIGN PATENTS OR APPLICATIONS Pemlidisboth Mich- 197.927 4/1908 Germany 72/353 [22] Filed: May ll, 1973 Primary Examiner-Richard J. Herbst [2 1] Appl&#39; 3S9456 Atwrney, Agent, or Firm-Hauke Gifford Patalidis &amp;  
 Dumont [52] US. Cl. 72/354; 72/370; 113/116 BB [51] Int. Cl. B2ld 9/14 57 ABSTRACT [58] Field of Search ..72/341;,l;/5l3l,63&#39;]73(]); A length of tubing is initially positioned within a sleeve encom assing a piston which axially comh b f i d&#39; ll (1 presses t e tu mg to orm successive ra 1a y outwar [56] References Cited corrugations beginning at one end, with the corruga UNITED STATES PATENTS tions progressively retracting the sleeve from the 1.486.976 3/1924 Lindgrcn 72/359 length of tubing.  
 2,268,838 H1942 Lyon 72/354 2.485.969 10/1949 Johnson 72/370 9 Chums, 2 Drawing Flgures PRESS TUBE CORRUGATING APPARATUS AND METHOD BACKGROUND OF THE INVENTION 1. Field of the Invention My invention relates to the art of forming corrugations in tubing and more particularly to an apparatus and method thereof to form uniform closely adjacent series of corrugations in successive lengths of tubing.  
 2. Description of the Prior Art Many tube corrugating systems are in present use. but complex problems arise in attempting to form precisely uniform corrugations with uniform tube wall thickness. without using very complex and expensive equipment.  
 SUMMARY OF THE INVENTION My invention solves the aforesaid problems by providing an inner mandrel or piston which closely fits the tubing and operates to axially compress a given length thereof. which is initially retained within a sleeve such that successive corrugations are expansively formed beginning at one end of said length of tubing. with each corrugation retracting the sleeve for formation of the next successive corrugation. The sleeve functions to prevent erratic tube deformations and each corrugation forms itself to the extent determined by the tubing material&#39;s natural configuration.  
 BRIEF DESCRIPTION OF THE DRAWING DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 illustrates a length of tubing 10 being corrugated as at 10:! as it is axially compressed between a shoulder 12a of a mandrel or piston 12 extending through the tubing 10 and an abutment 14 through which the piston also protrudes.  
  A sleeve &#39;16 closely surrounds the tubing 10 and is retractable toward the right from the phantom line abutment l4 engaging position indicated in the drawing, preferably against the resistance ofa relatively low rate spring 18 which compresses between a shoulder or flange 160 on the sleeve 16 and the end of a machine housing 20 or the like as shown.  
  In using this apparatus in the corrugating method of the present invention. in an initial position as end 1212 of the piston 12 is located as indicated in phantom line A just within the abutment member 14, and the sleeve 16 is extended to the left with its end 1612 adjacent the abutment 14. The inner surface of the sleeve end 1611 is preferably chamfered as shown in the drawing.  
  The length of tubing 10 will be located in the annular space between the piston 12 and the sleeve 16, with its ends respectively engaging the abutment l4 and the shoulder 12a of the piston 12. which is in the phantom line position indicated in the drawing.  
  Upon the application of axial pressure by the piston 12 moving towards the left. executed through any desired means such as an ordinary hydraulic press 22, a first corrugation will be formed expansively at the abutment end of the tubing. which corrugation cams the sleeve 16 an incremental amount corresponding to such corrugation toward the right. After this first corrugation becomes flattened. a second corrugation will form in the same fashion, forcing the sleeve 16 to the right another increment and so on. with said corrugations being successively formed from left to right and each successively retracting the sleeve 16 until the entire or other desired length of tubing has been corrugated. The piston 12 can then be retracted so that its end 121; takes the phantom line position B outwardly of the abutment 14, which may then be moved out of position as indicated by the arrow. and the corrugated length of tubing removed.  
  The corrugations 10a are of course flattened to the extent permitted by the type of tubing material and the thickness thereof used. so the tubing may thereafter be expanded axially to the degree necessary for separating the corrugation. dependent on the use to which the tubing may be put.  
  FIG. 2 illustrates in diagrammatic fashion the adaptation of the present invention to a continuous corrugation forming method. in which a continuous tubing 30 is formed from flat stock by any suitable forming rolls or the like (not shown) and its seam welded by any suitable means (not shown). with the tubing being fed peripherally around a piston assembly 32 and interiorly of a sleeve 34, the piston 32 and sleeve 34 initially being located in the phantom line positions shown in the drawing.  
  Piston 32 preferably has an intermediate expansible portion 32a which is selectively supplied with hydraulic fluid through an internal conduit 36 to expand the portion 32a into tight engagement with the tubing 30. A previously corrugated section 30a of the tubing 30 will initially be clamped in the jaws of a die 38 or the like. the piston portion 320 will be expanded to grip the tubing 30 and the piston 32 then moved to the right as viewed in the drawing to successively form corrugations which will successively retract the sleeve 34 to the left toward its solid line position in the fashion described previously in regard to FIG. 1. When the piston 32 has moved to its solid line position shown, a set of corrugations will have been formed in a selected length of the tubing 30, after which the jaws of the die 38 will be moved outwardly. and the spring 40 shown will move the sleeve 34 back to the phantom line position as the length of now corrugated tubing moves to the right within the die 38, which can then close again. The piston 32 can then be retracted to its phantom line position. after which the process is repeated. All of these actions may be sequentially timed and the parts actuated automatically by any desired means.  
  It will be noted that the key to the present invention is the incremental retraction of the sleeve 16 as each corrugation is successively formed through the axial compression of the piston 12. Although the sleeve retracts against the resilience of a spring. it is not necessary to have any great resistance to such retraction. and other means may be provided to return the sleeve to its initial position after the formation of corrugations in a given length of tubing.  
  Also. it will be apparent to one skilled in the art to which the invention pertains that various other changes and modifications may be made to the apparatus shown and in the method. without departing from the spirit of the invention or the scope of the appended claims.  
 What is claimed is:  
 l. A tubing corrugating apparatus comprising:  
 a mandrel disposed through the interior of a length of tubing in sliding engagement with the inner surface of said length of tubing:  
 a sleeve slidable on the outer surface of said length of tubing in sliding engagement therewith. one end of said sleeve being initially positioned proximate one end of said length oftubing such as to leave unprotected at short length thereof: and  
 means applying compressive force to the ends of said length of tubing for forming successive radially outward corrugations beginning at said end thereof unprotected by said sleeve. said corrugations upon formation operating to progressively cammingly retract said sleeve from said end.  
 2. The apparatus of claim 1 including means resiliently urging said sleeve toward said initial position.  
  3. The apparatus of claim 1 wherein said mandrel comprises a piston and said means applying said compressive force comprises means retaining said one end of said length of tubing stationary. means on said piston engaging the other end of said length of tubing. and means moving said piston closing the space between said retaining and engaging means.  
  4. The apparatus of claim 3 wherein said retaining means comprises a stop member abutting said one end of said length of tubing and said engaging means comprises a shoulder on said piston abutting the other end of said length of tubing.  
  5. The apparatus of claim 3 wherein said retaining means comprises clamping means adjacent said one end of said length of tubing and arranged to selectively hold same stationary. and said engaging means comprises means on said piston selectively gripping the inside of said length of tubing.  
  6. The apparatus of claim 5 wherein said clamping and gripping means are intermittently actuated and said piston is reciprocal in timed relation to actuation of said clamping and gripping means to corrugate successive lengths of an endless tubing progressing through said apparatus.  
  7. The apparatus of claim 1 wherein the end of said sleeve is beveled to facilitate camming by said corrugation.  
  8. A method of corrugating a length of tubing comprising:  
 disposing said length of tubing over a mandrel in sliding engagement with the inner surface of said tub ing;  
 enclosing said length of tubing within a sleeve in slidable engagement thereon:  
 initially retracting said sleeve such as to uncover a short portion of said tubing proximate an end of said length of tubing; and  
 axially compressing said length of tubing to form successive radially outward corrugations beginning at the uncovered end thereof which thereupon progressively cammingly retract said sleeve from said end.  
  9. The method of claim 8 and including the step of repeatedly moving successive lengths of continuous tubing into position within said sleeve for successive corrugation forming compressions. l  
  UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. I 3,878,707  
 DATED April 22, 1975 INVENTOR(S) Tom H. Thompson It is certified that error appears in the aboveidentified patent and that said Letters Patent are hereby corrected as shown below;  
  Name of Assignee &#34;Claude A. Petalidis&#34; should be Claude A. Patalidis.  
  Column 1, line 59, after &#34;position&#34;, change &#34;as to -an.  
 Signed and Scaled this twenty-ninth D3) of .luly l975 [SEAL] Arrest:  
 RUTH C. MASON C. MARSHALL DANN Atusting Officer (nmmisxioncr uj&#39;Parents and Trademarks