US2218460A - Stretching machine - Google Patents

Description

Oct. l5, 1940. F. SINGER Er A1.

STRETCHING MACHINE Filed June 29, 1938 5 Sheets-Sheet l .mw @Q Oct. 15, 1940. F. SINGER Erm.

s'rRETcHING MACHINE 5 Sheets-Sheet 2 Filed June 29, 1938 ffii Oct. 15, 1940. F. SINGER Er Al.

s TRETcHING MACHINE Filed June 29, 1938 5 Sheets-Sheet f5 five/M525: fr@ ange/ 2 Hf/ed beb/ggd@ UCL l5, 1940. F. sxNGER ET AL STRETCHING MACHINE Filed Jun 29, 1958 5 sheets-sheet 4 Oct l5, 1940. F. SINGER x-:T Al.

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Patented Oct. 15, 1940 y UNITED STATES 2,218,460 sras'ronmo momma nfl-lt. singer, starnberg, ma

but. Germany;

VNlu'eln y tosaid Singer ti J e9. Applioalcgnnne comme ',i'his invention relates to an apparatus for producing solid metal articles like plates, sheets, strips and the like, the longitudinal cross section of which is uniformly or nonfuniformly varying 'Ihe invention herein disclosed bears a close asksociation with ,the invention disclosed in Patent No. 1,982,544, entitled Method and apparatus for elongating metal articles," granted November 27,

I 1934, to Fritz Singer, one of the Joint inventors herein, to which patent reference is hereby in- 7vited In that document there is disclosed a machine for uniformly reducing the thickness of sheets, strips, plates and the like, and the present l. invention is built along the lines of the invention disclosed in the patent referred to. embodies the principles thereof,V but additionally includes meansfor varying uniformly or otherwisethe thickness that is imparted to the work during the so reducing operation. Thus, it is possible to make a strip or plate of uniform taper or one of some special shape. the thickness of which varies but not in aimiform manner.

In accordance with the foregoing, a feature of 25 our invention resides in the provision of means vadapted to reduce or increase the space between the reducing roll and the article carrier in the intervalsvbetween successive'reducing or stretching strokes. In case the gap between the roll and the 30 article carrier is intended to be increased, such increasing can'be done after the completion of a stretching stroke and during the returnl stroke of the machine. However, in the event that such space should be decreased, such decreasing can :x5 only be effected toward the end of the return stroke and in the beginning of the stretching stroke. v

'I'he variations of the distance between the roll and the article carrier might also be accomplished o by lifting and lowering the article carrier rather than the roll, inasmuch asit is only a question of construction suitability whether the article carrier is reciprocated in'order to eect the stretch- Y ing operation or the roll isreciprocated for the 4; same. purpose. Also the controlling devices for lifting and lowering the article carrier or the roll,

as herein disclosed. may be of various designs and it is only a question of the most simple and effective construction as to which of the numerous ,-,0 possibilities of modern gearing and constructive technics is made use of. Inas'much as the apparatus of the type illustrated in Figures 6, 'l and 8 of Patent No. -1,982,544,her einabove referred to, permits unprecedented reduction rates to be ob- 5.'. tained,'the apparatus constructed in accordance Alfred nehm i laid Liebergeil lling 1938, Serb! No. 210,4

June 3l, 1937 (Cl. SOA-19) with' the present invention is intended to produce in a single operation articles having ends of different thickness. In accor'dance with theinvention disclosed in the above mentioned patent the material is not rolled in the manner of the known 5 rolling processes but is worked by spreading out portions of the article "projecting beyond the rolling surface of the article-carrier in the direction in which elongation takes place and reduction is effected with a consumption. of energy considerl0 `ably less than is required for known rolling proe-l esses, and furthermore, inasmuch as the roll is not subjected tb strains of iiexure vertically to the article, but only parallel thereto. the smallest clearances of thlcknessmay be obtained without ll necessitating the use of arched rolls. v l Other objects -and features of our invention will become apparent from a reading of the following specification in the light of the accompanying drawings, inwhich:

Figures 1 to 4, inclusive are side elevations of the stretching apparatus. mainly in section, showing the parts of the apparatus in diii'erent subsequent phases of the stroke, as follows: Figure 1 illustrates the position of the machine parts after finishing a return stroke; Figure 2 the position of the parts before the beginning of the stretching operation proper: Figure 3 after finishing the stretching operation; and Figure 4 before feeding theartlcle forward for the following stretching operation;

Figure 5 is a view ofthe machine taken in section through Figure 6 and Figure 8 is a front elevation of the apparatus with the crank drive in the foregroimd. There is disclosed in the patent already referred to a machine designed for reducing the thickness of elongated metal articles such as strips, plates, sheets and the like, by advancing the article, increment by increment, to a rotary roll and perymitting the roll to reduce the thickness of the article. increment by increment, yin accordance with the gap or space between the roll and the smooth-surface over which the work is being fed. This' latter surface, although smooth, is interrupted in a most important manner, as described in the patent, in order to eil'ect the reduction. The present invention incorporates the features and designs of construction and operation shown in the patent, and accordingly reference is invited to the patent for an understanding of the basic invention. The main purpose of the present contribution isto so modify the machine disclosed in the patent that instead of producing u articles of uniform cross section it will be capable of producing articles of varying cross section.

Construction of machine On a base plate I0 there are mounted four vertical columns, I2, I2 and I4, I4', the upper ends of which are connected together by means of a cross head I6. Within recesses of the columns l2, I2 and I4, I4 are positioned bearings lI8, I8

y'and 20, 20' which are adapted to receive and support the Journals 22, 24 of a reducing roll 25.

As shown in Figure 5, the bearings I8 and 20 are formed on the'upper extremities of shafts 26, 28, which vshafts are mounted in vertical bores 30, 32 for vertical movement against the action of compression springs 34, 36.

A plurality of wedge-mocks 3a, 4o are associ-v ated with the cross head 4, and are adapted to cooperate with a double wedge member 42, 44 mounted immediately above the bearings I8 and 20'. The compression springs 34 and 36 may be replaced by any suitable supporting devices vsuch as hydraulic cylinders and serve to maintain the bearings I8; 20, the roll 25, the bearings I8', 20', and the double wedge block 42, 44 in upper, assembled position.

The double wedge 42, 44 carries a screw member 48, which is engaged vby an interiorly screw threaded nut 50. The latter is rotatably supported on a bearing 52 carried by a. bracket arm 54 extending outwardly from the machine frame and is provided at its outer extremity with a hand wheel 56, by means of which the nut may be rotated to impart rec/iprocation to the screw 48 and the attendant double Wedge member 42, 44. It will be understood that the roll 25 may thus be raised and lowered by;rotation of the hand wheel 56 and the nut 50.

In order to produce solid metal articles the4 thickness of which varies either uniformly or nonuniformly, means must be provided for controlling the movement of the double wedge in order to vary and to regulate the sequence and amount 0f movement of the roll 25, toward or away from the work piece or metal stock. In certain instances the hand wheel 56 may sufce for this purpose but in many instances the rapid sequence l of strokes in the operation of the machine will not permit sufficient time for manual operation.

This observation is particularly significant with `respect to uniformly tapered sheets or plates.

Accordingly, a'pawl and ratchet arrangement is provided for automatically or mechanically operating the roll-control mechanism, which latter includes the screw 48, the nut 50, and the double wedge member 42, 4'4. As illustrated, a detent or pin 60 is mounted eccentrically on the journal shaft 22 and is arranged to engager a projection 62, extending laterally from a lever 63, on each rotationv of the reducing roll 25. The double arm, or bell crank, lever 63 carries a pawl 64 at its lower end, which pawl is urged, by means of a spring 66, into engagement with a ratchet `wheel 68, and at its upper extremity is provided with an extension 10 which, by means of a spring 12, is urged into engagement with an adjustable abutment 14. f f

The ratchet 68 may be formed integrally with the nut 50 in order that all movement imparted to the ratchet will be conveyed to the screw 48 and wedge bar 42, 44. Thus, in operation, each time the reducing roll 25 rotates, the pin 60 strikes the projecting arm or pin 62, causing the pawl 64 to engage the teeth of the ratchet 618, thereby .fimparting partial rotation to the nut 50 and.V

some sught emprunt of endwise movement to the screw 48.

The base plate I0 of -the machine is provided with a plurality of bearings'80, 82 which receive a crank shaft 84 for driving the machine., The

shaft 84 is connected with a suitable source of' formed in the carriage and the lower lengthf wise portion of which slides in a groove formed in the slide-block 92. This latter member 92, is, in turn, guided within a recess 96 formed within the base, as shown in Figure 5. The carriage 90 supports an elongating surface 9| lying in a horizontal plane and -a supporting surface 93, the two surfaces being inclined toward one another and intersecting atsome pointas 95.

In order to hold the article being worked out of contact with the roll during the return stroke of the latter, the slide-block 92 must be periodically lowered and periodically raised to bring the work into engagement with the roll on the forward or reducing stroke of the latterv and to move it out of engagement during the return. To this end, the movement of the carriage 90 during certain portions of the stroke is transmitted to'the slide-block 92 by means of abutments |00, |02 formed on the carriage, engaging or striking the opposite extremities of a. reciprocal .guide bar |04. The reciprocal bar |04 is guided within a recess formed in the slide-'block 92 and is arrangedto co-act or cooperate with a plurality of abutments |06, |08 in'a manner hereinafter to be more completely described. 'Ihese members |06, |08 are mounted within recesses formed in the base plate I0 and are adapted to be depressed within the recesses by means of the bar |04 against the action of the compression springs ||0 and ||2. The abutments or members |06, |08 are provided with shoulders ||4, ||6 and |,|8, |20 for a purpose presently to be described.

In order to hold the arti le rigid. on the carriageduring the stretching or working stroke of the roll, a friction plate |22 is provided and this plate is arranged to press against work piece periodically and to this end there is provided a bracket member |30 mountedon the carriage and a bell crank lever |32 mounted on the bracket. The short extremity of the bell crank |32 is connected with the brake, or presser plate |22, by means of arlink, as shown, and the4 long arm carries a cam roller |34 engaging Ca path |36 formed on a cam plate |38.

Feeding of the article during the stretching operation is brought aboutby apparatus now to be` f described. A sliding feed block |40 is guided within a recess |42 formed within the carriage and is actuated or reciprocated by .means of a bell crank llever |44 which is pivoted at |46 to' an extension |48 of the carriage. The upper extremity of the bell crank engages within a recess formed in the sliding feed block |40 and the lower end is adapted to be engaged alternately by a stationary abutment |50 and a spring Dressedb I.ng device |88, movement of which is controlled 1uy by means of a toggle mechanism comprising a bracket arm |88, a bell crank lever |82, and a link |84. The lever |82 carries a cam roller |88 which -moves over a cam path |88 formed on the cam plate |88 and during operation of the machine, as about to be described, this toggle mechanism serves to actuate the clamping or feeding mechanism.

'I'here remains only one feature of construction oi' the machine that has not been described, namely, the apparatus for driving the reducing or stretching roll. As illustrated, the roll is provided with a pinion gear |10 rigidly nxed to the i journal 22, as shown in Figure 5. A rack |12 is carried by the carriage 88 for reciprocal movement therewith and engages a toothed wheel |14 carried by a shaft |18 mounted in a bearing |18 formed in the column |4. r, On the end of the shaft opposite the gear |14 "is a second gear |18 which engages an idler gear |80 loosely mounted `on a shaft |82 carried by a swinging arm |84.

The arm is adapted to swing about the shaft |18 and its position with respect thereto may be xed by means of a bolt |88, the shank of which passes through an arcuate opening |88 formed in the arm |84. f

'I'his arrangement of the mechanism for driving the reducing roll .permits the driven gear |18 oi' Figure 6 to be substituted by gears of different sizes to vary the peripheral vspeed of the reducing roll within certain limits In case the stretching operation is to be performed without driving the roll 28, the swinging arm is secured in such a manner that the gears |10 and |80 are out of engagement with one another.

Operation of machine In operation, the position of the reducing roll is adjusted by means of the hand wheel 88 in order to obtain the desired initial wall or work thickness. In the position of the stretching ma-J chine parts, as illustrated in Figure 3, the work to be stretched, which generally is a strip, a sheet or the like, ls placed on the carriage 80 and passed through Vthe clamping mechanism |40, |88 until: it is engaged by the friction plate or jaw |22, whereupon the machine Ais placed in motion. After several idle rotations of the crank the end of the article will have been fed past the clamping device |22 into position to be engaged by the reducing roll 28. In order to illustrate the production of an article vhaving a uniformly ltapered thickness, the illustrations show the operation of the machine in the midst of a stretching operation rather than at the beginning or commencementthereof., Figure i illustrates the position of the press or stretching machine parts after the carriage 80 has finished its return stroke. During the completion of the return stroke the abutment |02 has forced backward the slide-block 92 and the guide bar |04, thus' lifting the carriage 80 into its working position. The s1ide-block 82 is held in this position by means oi' the shoulders I I8, I8 of the abutments |08 and |08. The work has then been advanced into a new stretching position, and is clamped by means of the abutment |88 engaging the carriage of the machine.

The clamping device |22 is still open. The

crank shaft 84 is rotating in the direction` of the arrow of Figure 1 and moves the carriage 00 to the right of the position therein illustrated,

.causing the rollers |84 and |88 to move out of engagement with the cam sections |88 and |88 into the position illustrated in Figure 2, and "additionally causing the compression springs |24, |28 to press the friction plate |22 into firm engagement with the article or work. Meanwhile the clamping and feeding device |40, |88 still remains closed due to the self-locking action of the toggle levers |82 and 84. The roll 28 comes into contact with the article and the stretching operation begins. By` means of rthe rack and pinion gear arrangement, hereinbefore described, the roll 28 is rotated in anti-clockwise direction.

During the continued rotation of the crank 84` the abutment |00 pushes on the left end of the guide bar |04 which is then moved to the right andforces downwardly the member |08 by the sloped portion of the guide bar having engagement therewith. At this point the cam roller |88 strikes on the abutment positioned at the extreme right of the cam plate |88, whereby the toggle lever |82, |84 is broken, thereby lifting the clamping plate |88. As soon as the abutment |00 touches the slide-block l 04 the stretching operation is completed. In the meantime the abutment |08 has been depressed by meansA of the sloping shoulder formed on the guide bar 04 so that the slide-block 82 comes out of contact with the shoulder ||8 formed on the member |08. In this position the free end of the lower arm of the bell crank lever |44 engages the spring actuated abutment |82 and the projecting pin 80, carried by the journal 22, strikes the cooperating pin 82 of the pawl and ratchet gearing.

During the last part of the movement to the right of the carriage 80 the guide bar |04 is, by means of the abutment |00, moved to the right in a downwardly sloping path and it contacts the shoulder |20 of the member |08. ,Thereby the carriage 80 is lowered so that the article being stretched moves out of contact with the reducing roll 28. Simultaneously the slide-block 82 permits the member |08 to be lifted into its upward position by means of the compression spring ||0. The shoulders ||4, |20 thus hold the slide-block |04 in its lowermost position.

The lower arm of the bell crank lever |44 is held fast by engagement with the abutment |82 and as the pivot point of the lever participates in the further movement to the right of the carriage 80 the slide-block is, by means of the upper arm of the lever, pushed to'the right until it contacts the abutment screw |54. The actuating pin 80 which projects from the journal 22 imparts a clockwise rotation to the lever 88, which rotation is in turn transmitted to the ratchet wheel 88 by means of the pawl 88. 'I'he ratchet wheel 88 being secured to the nut 80 and the nut 80 being rotatably mounted in the bearing 82 o f the arm 84 of the cross head 4, rotatably ybut/not axially movable, rotation of the lever 88 causes the double wedge 42, 44 to be moved slightly from the right to the left, as illustrated in Figure 5. Such shifting of the doublewedge causes the reducing roll 28 to be lifted and the gap between the roll and the elongating surface 8| of the carriage 8l .-to be slightly increased for the nextsucceeding ing uniform wall thicknesses or articles having wall thicknesses which are uniform at least for a portion of the length of the work, it is only necessary to disconnect the operation of the pawl and ratchet wheel gearing by removing the abutment pin 62 during the stretching of the whole piece or the parts having the uniform thickness.

During the return stroke of the machine the cam roller |66 of the lever |62 engages the path |66 of the cam plate` |36 to effect closure of the clamping device |40, |56. Shortly thereafter the cam roller |34 .of the lever |32 engages the cam path |36 of the cam plate |38 and causes the clamping device |22 to open. During this return stroke the reducing roll 25 rotates in a clockwise direction, whereby the projecting pin 640 moves out of engagement with the cooperating abutment pin 62. The lever 63, due to the action =of the tension lspring 12, is returned to its initial position which is controlled by the adjustment of the abutment screw 14. The pawl 66 slides idly over the teeth of the ratchet wheel during this portion of the stroke. In approximately the same position of the stretching machine parts, in which the cam roller l|34 comes into engagement with the cam path- |36, the abutment |02 engages the guide bar |04, which latter part thereby participates in the movement to the left ofthe carriage and depresses` the member |06 by engagement therewith of the sloping portion formed on the under side of the left extremity of the guide bar |04. During the further course of movement to the left of the carriage the arm of the lever |44 engages the abutment |60. Thereafter, as the pivot point of the lever` |44 continues .its movement to the left, the upper arm of the lever will impart to the-closed clamping device" |40, |69 a movement in advance of that of the carriage, the extent of A which movement will be limited by the position of the abutment |66. Thus, the article to lbe stretched is advanced, increment by increment, into new stretching positions and the rate of feed is adlustably controlled by -means of the abutt ment screw |64 and the abutment |62.

During the end off the return stroke the slide` block 92 is restored to its initial position by means of the abutment |02. Therebythe member |06 is permitted to return to its uppermost position due to the action of the compression spring ||2, whereupon the slide-block 92 is then held in position by means of the shoulders H6, N9.

v at the end of the retumstroke the stretching machine parts have been restored to the position illustrated'in Figure l. A new increment or secrtion of the article to be stretched is ready for Ithe stretching operation and the gap between the roll and the elongating surface 9| has been slightly increased. Inasmuch as the roll is lifted not during the stretching operation proper butafter finfishing the stretching stroke, in the manner de scribed, it is .not possible to produce articles of entirely uniform tapering wall th'wknesses. The

` l anticles produced according .to this invention actuallyconsist of small sections or increments of uniform wall thickness, of which sections the one rabrupt formation of steps.

inmediately following shows a vslightly greater thickness' than the preceding one. As the difier-` ence in the wall thicknesses between one section and the following one is less than .0004 inch, such deviations from the actual geometrical shape are of no practical impontance with sheets of tapering wall thicknesses.

It must be further realized that the roll acts during each stretching operation also on precedin engagement with the roll during the first pari:l

of the working stroke. Thus, referring Ito Figure 1, as shown, -the elongaitng surface 9| is parallel with the line of the stroke of l'the roller 25 with the result that the thickness of the reduced stock for each stroke'wll be uniform. If, however, the elongating surface 9| is inclined toward the stroke of the roller 25 so .that if the stroke of the roller 25 were indenitely lengthened ift would engage the elongating surface 9|, the .thickness of the worked metal will not be uniform but in itself will be .tapering so as to make it possible to taper the metal for eachstroke to-approximately the taper of .the finished sheet. Thus, if the stroke f of the -roller 25 between the .position shown in Figure 1 and the position shown in Figure 3 is considered to be X and if the clearance betweeny the roller 26 and the elongating surface 9| is increased for each stroke by .the distance Y, it folstroke in Figure 2 between the roller v25 and the elongating surface 9| (see Figure 1) is Z and the clearance between the Iroller 25 and the elongat- -ing surface 9| at the end of the stroke or positalon shown in Figure 3 is Z-Y, .then inasmuch as Y is the increased clearance for each stroke, Z-Y must have been the clearance between the roller 26 and the elongating surface 9|,in Figure 2 lalt 'the beginning of the previous stroke with theresult that each stroke gives a tapering surface -to the limited portion shaped corresponding to the general taper of'thefinished article.

It is important that .the disclosure of my Patent No.. 1,982,544 be borne in mind, because the method of stretching the metal makes it possible to obtain a low pitch tapered sheet which could not be obtained by other known methods. As is said in that patent, `stretching the metal ina direction away from .the unlengthened portion and not as in known processes in the opposite direction permits of a rate of elongating of cold metal', not otherwise possible. Because of this, it is possible to utilize an automatic means varying .the lthickness of the finished product whereby the generally uniform taper will result.

Having thus described rUhe invention, what we claim as new and desire to secure by Letters Patent ofthe United States, is: f ll. A stretching apparatus of the character described for producing soiidmetal articles of varying thickness, comprising, in combination, a supporting surface yfor an article -to be worked, an elongating sinface inclined to the supporting surface, means for reducing land drawing out increto said reducing `and drawing means for successive lengthening, and means for varying the distance between said reducing and drawing means and the elongating surface directly with the adv-ance of the article through the stretching apparatus.

2. A stretching apparatus of .the character described for producing solid metal articles of varying thickness, comprising, in combination, a. supporting surface for an article to be worked, an elongating surface inclined to the supporting surface, means for reducing and drawing out increments of the article against said elongating surface in a direction away from the remainder of the article, means for periodically effecting rela? tive movement between said support and said article to expose succeeding portions of the article to said reducing and drawing means for successive lengthening, and means for varying the distance betweensaid reducing and drawing means and .the elongating surface directly with the advance of the article through the stretching apparatus during t parts of 'the strokes wherein reducing and elo ting do not .take place.

3. An apparatus of the character described in claim 1, wherein the means for varying the distance between the reducing and drawing means on the elongating surface are automatilly actuated by means operable during only that part of the stroke wherein no compressive strain is caused by the variation of said distance.

4. A stretching apparatus of the character described comprising, in combination. a supporting surface for an article to be worked, an elongating surface inclined to .the ysupporting surface, means for -reducing and drawing out increments of an article advanced from Ithe supporting surface toward .the elongating surface in a direction away from Ithe unworked portion of the article, a reciprocating carriage for the supporting sur- 4face and .the elongating surface for' bringing the reducing and drawing means into operable relationship with the elongating surface, and means for lowerlng- #the reciprocating carriage toward the end of the working stroke and lifting it again toward lthe end of the idle stroke. y

5. An apparatus of the character described in .claim 4 comprising a wedge shaped slide block guided in .the base plate o! the apparatus on which slide block the reciprocating carriage is slidably mounted, and abutments formed on the reciprocating carriage adapted .to move 'the slide block in opposite directions so as to lower the slide block and the reciprocating carriage toward the end vof the working stroke and to lift them toward the end of the idle stroke.

6. The method of producing a solid metal article having longitudinally a generally tapering cross section which comprises advancing the metal article beyond the edge of a supporting surface, moving a reducing and drawing means into engagement with Ithe metal article along a path oblique to the supporting surface and parallel .to an elongating surface in a direction away from .the unworked portion of 1t'he metal article, and increasing the clearance between the elongating surface and the reducing and drawing means by regular steps as the metal strip is advanced beyond the edge of :the supporting surface.

FRITZ SINGER.

ALFRED LIEBERGELD.

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