US1596393A - Means for indenting radiator tubes - Google Patents

Description

Aug. 17 ,1929.4 A 1,596,393

R. W. BYOWNE MEANS FOR NDENTING RADIATOR TUBES /5 FlgJa 20,31923 Patented Aug.l 1 7, 1926.

UNITED STATES PATENT OFFICE.

RAYMOND W. BOWNE, OF LYNN, MASSACHUSETTS. ASSIGNOR TO UNITED STATES CAR- TRIDGE COMPANY, OE LOWELL, MASSACHUSETTS, A CORPORATION MASSACHU- SETTS.

MEANS FOR IN DEN TING-*RADIATOR TUBES.

Application led January 20, 1928. Serial No. 613,884.

This invention pertains to the manufacture of thin metallic tubes such for example as are employed in the manufacture of radiators for use with internal combustion engines. and relates more particularly to means for forming indentations inthe cylindrical walls of such a tube-without crushing, warping. or unduly straining the ma terial of the tube as a whole.

.ln order t'o break up the air stream lowing through such radiator tubes, it has been found expedient to provide projections upon the inner surfaces of the tubes which act as bal'lles' producing swirls and eddies in the stream ot air so that substantially every molecule of the flowing air is brought into intimate, heat exchanging Contact with the tube wall. lVhen such tubes are formed from thin metal, as for example Seamless copper tubing 'such as may be produced by an extrusionprocess, Athe only practical mode of forming the battles or inwardly directed projections, is to indent the tube by pressure from the outside, but as these tubes are sometimes only .006 of an inch thick, it

is. manifestly dillicult t6 form the indentations without seriously distorting the tube as a whole or stressing the metal at lor near the indentatious to an undesirable degree. I0 The object of the present invention is accordingly to provide improved means capable of forming the desired indentati'ons in suoli tubes accurately and expeditiously and' without damage to the tube as a'whole or 5 imposing undue strain upon the metal adjacent to the indentations, and embodying provisions for minimizing wear of the indenting elements as well as for adjusting such elements to compensate for any wear which may occur. In the accompanying drawings a preferred embodiment of the invention is illustrated by way of example, and in such drawings:

Figure 1 is a fragmentary vertical cross P sectional view 'of a machine adapted for perforniing the indenting operation and embodying tubo clanlping and indenting elements constructed in accordance with the present invention. k

Fig. 2 is a front elevation of one of the clamping jaws of the machine 'of Fig. 1,

showing the present improvements as applied thereto.

Fig. 3 is a horizontal cross section on the line 3-3 of Fig. 2 looking in the direction parts of the tube being broken away for clearness in illustration; and

Fig. 8 is a side elevation of a completed j tube showing one series of the indentations formed therein.

The nume-ral 1 indicates the bed or table ofthe machine mounted upon legs such as 2. and being provided with an opening or slot 3 for the discharge ofthe completed tubes. A bracket 4i's secured to the table 1 and vserves to support the fixed clamping jaw or block 5, hereinafter more fully described. At the opposite side of the slot 3 the table or bed is furnished with a support 6 above which is mounted the bracket 7 providing an inclined guideway or chute 8 for the tube blanks 9. The bracket 7 is spaced from the support 6 to provide a guideway for a slidingmember 10 which is reciprocated in any desired .manner common to the art.` A flanged portion 11 ofthe movable clamping jaw or block 12 is secured to the end of the slide member'lOby means of screws such as 11.

Referring' to Figs. 2, 3, and 4, the fixed clamping jaw or block 5 is shown as provided with a vsubstantially flat vertical face 13 preferably machined off smoothly and true. A substantially semi-cylindrical recess 14. is formed in this face extending transversely across the block 5 with its axis substantially horizontal. A series of bores 15 is formed in the block 5 at either side of the recess 14. These bores are preferably to the axis of the recess 27 perpendicular to the surface 13 and .intersect the latter at the opposite edges of the recess 14. As herein shown three 'of such bores are arranged at one edge of the recess and two at the other, the bores of the two series being staggered relatively to each other. These bores are internally screw threaded for the reception of screws such as 16, and these screws are furnished with 'substantially spherical heads or ends 1-7 cqnstituting die members which project into the recess 14 at opposite sides thereof. In order to retain the screws 16 in properly adjusted position, plugs such as 16a may be inserted in the recesses behind the screws if desired.

Two or more bores 18 are also formed in the block 5 intermediate the two series of bores 15. These bores 18 open into the recess 14 at points substantially midway between the edges of the latter, but where they enter such recess they are-of reduced diameter. Pins 19 are arranged to slide within the reduced portions ofthe bores 18, and these pins are provided with enlarged heads 20 which serve to limit outward movement of the pins. Springs 21 seated in the bores 18 tend normally to project the pins 19 into the recess 14, such springs bearing at their outer ends against a plate 22 secured to the block 5 by means of screws 23 (see Fig. 4). This plate in turn is provided with threaded openings for the reception of bolts 24 by means of which it is secured to the bracket 4 as above referred to. A pair of bores 25 of small diameter is also provided in block 5, such bores opening into the face 13 of the block to one side of the recess 14, the purpose of these bores being hereinafter described.

Referring to Figs. 5 and 6 the movable clamping` block or jaw 12 isv shown as furnished with the finished vertical face 26 in which is formed a semi-cylindrical recess complemental to the recess 14. A pair of pins 28 project from the surface 26 of the block 12 and are so spaced as to enter the bores 25 in the block 5 as the movable block 12 is brought into operative relationshi to the block 5. When the movable bloc is broughtinto engagement with the fixed block 5, the semi-cylindrical recesses' 14 and 27 t0- gether constitute a cylindrical tube-receiving chamber of a diameter substantially equal to the external diameter of the tube to be indented.

The block 12 is provided with a series of bores 29 which open into the recess 27 at points` substantially midway. between the edges of the latter. These bores preferably extend substantially radially with respect and are internally screw threaded for the reception of screws such as 30. As shown in Fig. 6 these screws are provided with end portions 31 whlch bear against and serve to posltlonballs 32 constituting die members seated in the ends of the respective bores and which project into the recess 27. As shown in Fig. 5 the block 12 is provided with four of the bores 29 and with a corresponding number of balls Preferably these bores are so disposed that the two inner ones of the series of balls 32 lie in the same radial planes as the spherical ends 17 of the screws 16 at the lower edge of the recess 14 of the block 5 as viewed in vFig'. 2. When the block 12 is moved toward the block 5, the spherical die members 17 of the block 5 would normally engage with the face 26 of the block 12 and prevent close contact of the face 26 with the face 13. To permit actual engagement of these faces, the face 26 is provided with recesses 33 and 34 into which the die members 17 may project as the clamping jaws are brought into engagement.

In F ig. 7 ldie elements useful in forming hexagonal heads upon the tubes either during or after indentation thereof are shown. For this purpose the female die elements 35, 36 are disposed at opposite ends of the block 13 cooperating with the corresponding male die elements 37 having hexagonal end portions 38 which enter the ends of the tube and serve to expand such ends outwardly into heads of hexagonal form. These head forming die elements, however, form no part of the present invention.

In the operation of the device the lowermost tube blank 9EL is released from the chute 8 and is engaged by the edges of the recess 27 of the block 12. uitable means not shown, but common to the art, may be employed for supporting ,the tube in this osition as the clamping block 12moves to t e left and into engagement with the block 5. As the blocks come into engagement the spherical die elements 17 and 32 impress the cylindrical walls of the tube with indentations such as indicated at 40 in Fig. 8. During this indentation of the tube the main body thereof is clamped firmly within the cylindrical chamber formed by the walls of the recesses 14 and 27 so that it is .impossible for the tube to bulge or warp, out of its true cylindrical shape'under the pressure exerted bythe die elements. As these die elements are of spherical curvature they form smoothly rounded depressions in the tube which merge grad` ually into the main wall of the tube without producing any sharp line of demarcation such as might result in the formation of incipient cracks or lines of strain. By reason of the arched form of the tube, the pressure of a spherical die against its wall results in the production of spherically curved depressions which are elongated in an axial direction.

If it be desired to form the hexagonal heads upon the tube while the tube is 'clamped betweenl the blocks 5 and 12the dies 35, 36 and 37 may be actuated to produce such hexagonal heads before the block 12 is retracted. -After the indentations have been formed, the block 12 is retracted and the pins 19, which have been depressed during the indenting operation, spring outwardly forcing the finished tube from the recess 14. In Fig. 8 the finished tube is shown as provided with the hexagonal heads and with the indentions 40 in its cylindrical surface.

When die elements of the type shown in Fig. 4 are employed, it is clear that if the face 13 or the recess 14 of the clamping block become worn, the die elements may be retracted, and the face of the block plan-ed oli to secure a new surface, after which the die elements may be advanced to normal operative position. It is also clear that as the die elements themselves are worn they may be advanced by rotation of the screws 16 or may be withdrawn and replaced by new ones. If the arrangement shown in Fig. 6 be employed, the die elements 32, which consist of hardened steel balls, may readily be rotated when worn by retracting the screws 30 slightly and turning the balls within the bores 29, whereupon the vscrews may be tightened to retain the balls-in position. Alternatively with this latterarrangement, the balls may be left free t'o turn, so that they will continuously present free surfaces for engagement with the tube. It is contemplated that either or both forms of die may be employed to the same machine as desired.

That I claim and desire. to secure by Letters Patent of the United States is:

1. Apparatus of the class described comprising tube clamping means, and means for forming a plurality of longitudinally spaced axially elongate spherically curved indentations in the wall of the tube. I

2. Apparatus of the class described comprising tube positioning means, and means for forming spherically curved axially elongate indentations in the cylindrical walls 0f the tube. Y

3. Apparatus of the class described comprising tube holding means, and means for forming a plurality of series of longitudinally spaced spherically curved axially elongate indentations in the cylindrical Wall of the tube.

4. Apparatusof the class described comprising tube clamping means, and means for producing a plurality of circumferentially and symmetrically spaced series of longitudinally spaced axially elongate, spherically curved. indentations in the cylindrical wall of the tube.

5. Apparatus of the class described comrising relatively movable tube clamping jaws, one at least of said jaws having a plurality of spherically curved projections for engagement with the cylindrical surface of vthe tube for indenting the latter.

6. Apparatus of the class described comprising relatively movable tube clamping jaws, and a removable die member having a spherically curved tube indenting surface projecting from each of said jaws for engagement with the cylindrical wall of 'a tube clamped therebetween.

7. Apparatus of the class described comprising relatively movable clamping jaws provided with complemental recesses forming atube receiving chamber and series of longitudinally ,spaced spherically curved elements projecting into said chamber for indenting the cylindrical wall of the tube, one of said series comprising a lesser number o f projecting elements than another serles.

8. Apparatus of the class described coinprising separa-ble elements provided respectively with complemental recesses constituting a cylindrical tube receiving chamber, and three series of axiall spaced die elements projecting inwardly fyrom the walls of said chamber for indenting the cylindrical wall of a tube positioned therein, said series being spaced substantially equally apart in a circumferential direction.v

9. Apparatus of the class described coinprising relatively movable tube clamping jaws having complemental recesses forn'iing a tube receiving chamber, and series of die members projecting into said chamber and extending longitudinally thereof, said dies having 'spherically curved tube engaging surfaces the die members of one series being staggered relatively to those of an adjacent series. c

10. Apparatus of the class described comprising relatively movable tube clamping jaws having complemental recesses forming a cylindrical tube receiving chamber. and a` plurality of independently adjustable d ie members spaced symmetrically about the axis of said chamber, said die members having spherically curved tube engaging surfaces for indenting the circumferential `wall of the tube.

11. Apparatus of the class described comprising a pair of tube clamping jaws, a series of die memberspprojecting from one jaw, and two-series of die members projecting mfrom the other jaw, belng so disposed as to engage the tube symmetrically with respect to its axis.

12. Apparatus of the class described comprising a pair of clamping jaws each having a substantially semicylindrical recess collectively constituting a tube receiving chamber,.a die projecting from one of said jaws into its recess at a point disposed substan- Itially midway between the edges of the. recess, and dies .projecting from theother jaw at opposite edges of its recess.

13. Apparatus of the class described corni tuting complemental halves of a tube receiving chamber, a series of longitudinally spaced die elements projecting from the wall of one of said recesses, said series being spaced equally from the edges of the recess, and a series of longitudinally spaced 'die elements'projecting from each edge of the other of said recesses. y

14. Apparatus of the class described comprising tube clamping elements providing a tube receiving chamber, a die element projecting inwardly from the wall of said chamber, and means for adjusting said die element to project to a greater or lesser extent from the wall of the chamber.

15. Apparatus of the class described comprising a clamping member having a tube receiving recess therein, said recess having a cylindrically curved wall, a die element normally projecting from the wall of said recess, and means permitting said die element to be withdrawn from the recess.

16. Apparatus of the class described comprising a clamping block having a tube receiving recess therein and a bore opening into said recess, a die member positioned within the bore and normally projecting into the recess, and adjustable means for retain-y ing said die member in operative position.

17. Apparatus of the class described comprising a clamping block having a substantially semicylindrical recess in one face thereof for the reception of a tube and a plurality of axially spaced radially extending bores opening into said recess, said bores being internally screw threaded, a die member positioned within each bore and projecting intothe recess, and means engaging the screw threads of the respective bores for holding the dies in operative position.

18. Apparatus of the class described com- `Iprising. complementally recessed elements providing aY substantially receiving chamber, series of axially spaced bores in said elements opening into said chamber, each of said bores being internallyY screw threaded, a die member seated in each bore and normally projecting into the chamber, and threaded means engaging the respective bores for holding the'dies in operative position, dies of the several series being space'd symmetrically of the circumference of the chamber.

19. Apparatus of the class described comprising a tube clamping block having a semicylindrical recess therein and series of bores openin into said recess at the opposite edges thereo and die elements having operative surfaces of spherical curvature seated in the respective bores and projecting into the marginal portions of said recess.

20. Apparatus of the class described comcylindrical tube prising a pair of relatively movable tube clamping jaws having complemental recesses forming a tube receiving chamber, spherical die elements projecting from said jaws into the chamber, and spring actuated. members associated with one of said jaws for ejecting the tube from the recess therein upon completion of the operation.

21. Apparatus of the class described comprising a pair of relatively movable clamping jaws having complemental recesses forming a cylindrical tube receiving chamber, a

series of spherical die elements projecting into the chamber from the opposite edges of the recess in one of said jaws, and spring actuated pins normally projecting into said latter recess between A`the series of die elements for ejecting the tube from said recess after the completion of the operation. Y

Signed by me at Lowell, Mass., this 6th day of Jan., 1923.

RAYMOND W. BOWW

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