US2636541A

US2636541A - Machine and method for forming collapsible tubing

Info

Publication number: US2636541A
Application number: US86635A
Authority: US
Inventors: Charles E Rutherford
Original assignee: Wiremold Co
Current assignee: Wiremold Co
Priority date: 1949-04-11
Filing date: 1949-04-11
Publication date: 1953-04-28
Anticipated expiration: 1970-04-28

Description

April 1953 c. E. RUTHERFORD MACHINE AND METHOD FOR FORMING COLLAPSIBLE TUBING Filed April 11, 1949 2 SHEETS-SHEET l filll'llfo r:- C Earle-515. Rulifcerf if M April 28, 1953 c. E. RUTHERFORD MACHINE AND METHOD FOR FORMING COLLAPSIBLE TUBING Filed April 11, 1949 2 SHEETSSHEET 2 Jrutrofo CECLrZeSER Patented Apr. 28, 1953 MACHINE AND METHOD FOR FORMING COLLAPSIBLE TUBING Charles E. Rutherford, West Hartford, Conn, as-

Signor to The -Wircmold Company, Hartford, Coma, a corporation of Connecticut Application April 11, 1949, Serial No. 86,635

13 Claims. 1

This invention relates to collapsible tubing formed of two elements and also to methods and machines for making such tubing.

It is an object of this invention to provide an improved form of two element collapsible tubing in whichthe flexible element is made and-assembled so that it tends to fold outwardly when the tubing is collapsed, thus not to impede the flow of air or fluid through the tubing.

Another object of this invention to provide a method for forming the improved tubing.

Another object of the invention is to provide an improved machine for forming the new tubing.

Another object is to provide improvements and attachments adaptable to known collapsible tubing machines for producing the new tubing.

Other objects and advantages of the invention will become apparent as it is described in connection with the accompanying drawings.

In the drawings:

Fig. l is a fragmentary perspective View partly in section of the portion of the machine which embodies the invention for making the improved tubing;

Fig. 2 is an extension of Fig. 1 illustrating the entrance of the fabric guide;

Fig. 3 is a plan view partly broken away and partly in section of the machine shown in Fig. .1;

Fig. 4 is a plan view of the fabric guide showing its relation to the first and second convolutions of the spiralled channelled metal member;

Figs. 5-8are transverse section'views of the fabricguide, taken along lines .55 to .88 of Fig.4.

This inventionis an improvement on tubing, machine and method disclosed in the application of -A..E. Chernack, S. N. 705,539, filed October 23,1946, for Methodand Machine for, Forming Tubing, now Patent. No. 2,539,814.

Referring to the drawings a strip of thin sheet metal 20 which preferably is formed by any suitable means into channel shape by having its opposite edges bent into acute angles to form flanges 2| and 22 is fed to a rotating mandrel (designated generally by 36) and to a rotary pinching or pressure roll (designated generally by. numeral 50) and being guided in an advancing spiral path by a guideway it in a guide block 49, as will hereinafter be more particularly described.

Thecylindrical mandrel 313 isformed on a rotatingshaft 28 extending through theguide block 4! The mandrelfill also extends through the guide block 43 and is held in place on the. rotatingshaft 28by means ofa key (notshown) and holtd l soas to. rotatewith the shaft 28,.

The guide block it is a machined casting mounted upon a stationary casting 4 3 which may in turn be mounted upon a suitable machine frame, not shown. The guide block 40 has -a spiral guideway 42 rectangular in cross section cut into its vertical face around and'adjacent the mandrel 32! to receive the trailing edge 22 of the preformed channel strip 20. The pitch of the guideway depends upon the desired advance of the channel strip 20. Secured to the guideblock [it and substantially co-extensive with the vertical surface 49a thereof, is a guide or cam plate 45, also curved to a spiral shape and positioned so as to engage the body portion of the metallic strip. The guide plate cooperates with the spiral guideway 42 in forming the metal strip into a spiral of the desired pitch by bending the metal strip to closely fit the curvature of the mandrel. The guide or cam plate 45 may be secured to the guide block 40 by means of screws such as 46.

To guide the opposite side of the channel strip 20, a spiral guiding member or rib 35 is affixed at one end by a screw upon an extension 44 of the guide block as, the surface of the extension being horizontal and substantially tangential to the top of the mandrel 30. The guide rib 35 winds about one and one-quarter turns around the mandrel and terminates at that point. Its terminal end is not attached to the mandrel. The mandrel rotates within the guide rib 35.

In order to insert a strip FS of cloth or fabric or other limp flexible material i. e. lacking stiffness, fabric guide means is provided comprising an upper guide member H3 and a lower guide member 15. The guide means is fixedly positioned above the mandrel by supporting bracket '12 which may be attached to a fixed part (not shown) of the machine. The upper member it of the cloth guide is generally of inverted channel form converging at its exit end portion over the top of the mandrel as will be described. It may also be curved upwardly toward the entrance end. At the entrance end it has side flanges H, substantially perpendicular to the roof of the guide and extending downwardly. As the upper guide member proceeds toward the exit end it converges and the flanges are bent inwardly towards each other into acute angles or curved reversely toward the mandrel so as to tuckthe fabric under the forward edge of the first convolution of the metal strip and under the trailing edge of the second convolution. The tucking inof the fabric strip FS under the forward edge of the first convolution occurs at about the point or just prior to the point where the metal strip enters the spiral guideway 42 of the guide block 40.

In order to form an outwardly extending ridge or crimp in the center of the fabric strip PS the upper cloth guide member Hi is fluted or provided with a progressively-deepening downwardly-faced groove 14, the guide being formed into an upwardly and outwardly pressed ridge for that purpose and being greatest at the exit of the guide. The groove starts at a point near the entrance of the upper cloth guide on the center line thereof and progressively grows deeper.

Cooperating with the upper fabric guide It is a lower fabric guide member 16 formed as a strip of metal dimensioned to fit within the upper fabric guide 10 and having its top surface complementary to the inner surface of the upper guide. Thus a rib or ridge TI on the upper surface of the lower guide 16 presses the fabric into the groove 14 of the top guide 10 forming a crease or upwardly pointed crimp C along the center line of the fabric strip FS as it moves along and issues from the guides. The lower guide 16 may terminate short of the end of the upper guide member 10 and may also be short of the entrance end.

With the cloth inserted under the forward edge or flange of the first convolution and under the trailing edge or flange of the second convolution, the mandrel rotates these elements of the tubing to present them to a pressure or pinching roll 59. The pinching roll 50 is mounted upon a rotary shaft 68 and held thereon by a nut 49. The shaft 68 is parallel to the axis of the mandrel.

The driving means for the mandrel and the mounting and driving means for the pinching roll are omitted from the drawing for clearness. Those features being known to those skilled in the art and per so not being part of the invention, need not be illustrated. Preferably the shaft upon which the pinching roll is mounted is pressed by spring pressure in a known manner (not herein illustrated) so as to cause the pinching roll to press against the tubing with the desired pressure as the roll acts upon the tubing.

The pinching roll is provided with pinching flanges SI, 52 extending from opposite sides of the roll beyond the periphery of the roll, the flanges being spaced so as to straddle the guide rib 35. The flange 5| presses upon the fabric overlying the forward edge of the first convolution of the metal strip and the flange 52 presses upon the fabric overlying the trailing edge of the second convolution of the metal strip so that both of these edges are pressed down simultaneously to frictionally and securely hold the edges of the fabric strip FS under these flanges. The peripheral surfaces of the flanges 5!, 52 may and preferably do incline slightly inwardly as shown in Fig. 3.

During the formation of the tubing this crease H in the fabric is untouched since it passes between the flanges 5l 52 of the pinching roll while the side edges of the fabric strip are secured beneath the edges of the metal channel strip. As a result of the formation of the crimp in the tubing the fabric tends to move outwardly as the tube is collapsed. In this way the inward moving of the fabric as in prior collapsible tubing is avoided.

Tubing made according to this invention is claimed in my co-pending application Serial No,

193,250 filed October 31, 1950 which is a division hereof.

From the foregoing it may be observed that I have provided apparatus and means for forming collapsible tubing wherein the tubing is formed by the pressure of a single pinching or pressure roll and also the tubing is formed so as to cause the fabric to tend to move upwardly as the tubing is collapsed. It will be apparent to those skilled in the art that other means for making crease or crimp in the fabric may be employed and other means for bending the edges of the metallic strip upon the edges of the fabric strip may be used. Therefore I do not limit the invention to the specific embodiment illustrated in the drawings.

What is claimed is:

1. In a machine for forming collapsible twoelement tubing from a strip of limp material and a metal strip preformed into channel shape and having its edges bent to form flanges, a rotating mandrel, means to guide said channel strip around the mandrel in a spiral path, means to insert the edges of the limp strip under different flanges of adjacent convolutions of the metal strip simultaneously, and means to bend down the flanges simultaneously onto the inserted limp strip edges to secure them to the metal strip and to connect adjacent convolutions of the metal strip.

2. In a machine for forming collapsible twoelement tubing from a strip of limp material and a metal strip preformed into channel shape and having its edges bent to form flanges, a ro tating mandrel, means to guide said channel strip around the mandrel in a spiral path and to space one convolution from another, means to insert the trailing edges of the limp strip under the forward flange of one convolution of the metal strip and the forward edge of the limp strip under the trailing flange of a spaced adjacent convolution of the metal strip simultaneously, and means to bend down the flanges simultaneously onto the inserted limp strip edges to secure them to the metal strip and to connect adjacent convolutions of the metal strip.

3. A machine as claimed in claim 1 wherein the bending means comprises a pressure roller having peripheral radially extending flanges simultaneously engaging the flanges of the metal strip.

4. A machine as claimed in claim 2 wherein the bending means comprises a pressure roller having peripheral radially-extending flanges simultaneously engaging the flanges of the metal strip.

5. In a machine for forming collapsible twoelement tubing from a strip of limp material and a metal strip preformed into channel shape by having its edges bent to form flanges, means to secure the edges of the limp strip under the edges of the metal strip to form continuous tubing, means to feed the limp strip to the channel-form metal strip, and means associated with said feeding means to crease the limp strip longitudinally and outwardly of the tubing, said creasing means comprising stationary top and bottom guide members between which the limp strip passes, said members having complementary formations causing a crease to be formed in the limp strip as it passes between said guide members to cause the limp strip to fold outwardly when the tubing collapses.

6. A machine as claimed in claim 5 wherein said reasing means comprises a top guide mom'- her and a bottom guide member between which the flexible strip passes, said members having complementary formations causing the crease to be formed in the flexible strip as it passes between said guide members, and wherein said top guide member has its edges bent to guide the edges of the limp strip and insert them under the flanges of the metal strip.

7. A machine as claimed in claim 5 wherein the top guide member has a longitudinal groove progressively deepening toward the exit end, and the bottom guide member is formed complementary to the top guide member to cause the longitudinal outward crease in the limp strip as it passes between the guide members.

8. A machine as claimed in claim 5 wherein said top guide member has its edges bent to guide the edges of the limp strip and insert them under the flanges of the metal strip.

9. A machine as claimed in claim 5 wherein said top guide member has depending side portions inclined towards each other at the exit end to guide the edges of the limp strip and insert them under the flanges of the metal strip.

10. A machine as claimed in claim 9 wherein the top guide member has a longitudinal groove progressively deepening toward the exit end, and the bottom guide member is formed complementary to the top guide member to cause a longitudinal crease in the limp strip as it passes between the guide members.

11. The method of making collapsible tubing comprising forming a spiralled convolution from a preformed strip of metal having its edges bent to form flanges, forming a longitudinal crease in a limp strip prior to its presentation to the metal strip, forming two convolutions of said metal strip and spacing them apart, inserting the trailing edge of a limp strip under the forward flange of one convolution of the metal strip and simultaneously inserting the forward edge of the limp strip under the trailing flange of an adjacent convolution of the metal strip and bending down said flanges to secure together the metal and limp strips.

12. The method of making collapsible tubing comprising forming a spiralled convolution from a preformed strip of metal having its edges bent to form flanges, forming a longitudinal crease in a limp strip prior to its presentation to the metal strip, forming two convolutions of said metal strip and spacing them apart, inserting the trailing edge of a limp strip under the forward flange of one convolution of the metal strip and simultaneously inserting the forward edge of the limp strip under the trailing flange of an adjacent convolution of the metal strip, and simultaneously bending down said flanges to secure the metal and limp strips in adjacent convolutions.

13. A machine as claimed in claim 2 having means associated with said inserting means to crease the limp strip longitudinally and outward- 1y to cause the limp strip to fold outwardly when the tubing collapses.

C. E. RUTHERFORD.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 809,561 Greenfield Jan. 9, 1906 1,238,987 Colby Sept. 4, 1917 1,410,160 Brinkman Mar. 21, 1922 1,502,052 Naylor July 22, 1924 1,661,835 Keller Mar. 6, 1928 2,049,100 Baker July 28, 1936 2,069,052 Webb Jan. 26, 1937 2,195,751 Nichols et a1. Apr. 2, 1940 2,234,450 Quarnstrom Mar. 11, 1941 2,337,374 Chernack Dec. 21, 1943 2,340,794 Chernack Feb. 1, 1944