US2726562A - Stretching machines - Google Patents

Description

Dec. 13, 1955 HAASE 2,726,562

STRETCHING MACHINES Filed Aug. 13, 1951 5 Sheets-Sheet 3 INVENTOR fliiz lime,

ATT( )RNEY Dec. 13, 1955 F. HAASE 2,726,562

\ STRETCHING MACHINES Filed Aug. 15, 1951 5 Sheets-Sheet 4 ATTORNEY Dec. 13, 1955 F. HAASE 2,726,562

STRETCHING MACHINES Fil 15, 1951 5 Sheets-Sheet 5 INVENTOR. FRITZ HAASE BY W, ania/7, MW

ATTOZ/VEKS:

STRETCHING MACHINES Fritz Haase, Goppingen (Wurttemberg), Germany, assignor, by mesne assignments, to Tube Reducing Corporation, Wallington, N. J., a corporation of Delaware Application August 13, 1951, Serial No. 241,635

9 Claims. (Cl. 8019) This invention relates to a stretching machine for reducing the wall thickness of metal.

The invention further relates to a stretching machine for producing wedge-shaped strips or bands or other articles of like nature.

The invention further relates to a stretching machine in which a stretching tool cooperates with a counter-tool to reduce the thickness of metal fed into a gap therebetween, in combination with means for varying the gap; a machine having a stretching tool and counter-tool in combination with means for feeding metal thereto whose feeding rates are adjusted to the variations of the gap and/or the then existing reduction rates of the metal.

The invention further relates to a machine in which a roll segment rotatably mounted on a reciprocating slide cooperates with a counter-tool to reduce the thickness of metal fed into a gap therebetween, in combination with means for varying the gap; specific means for enlarging the gap during the return stroke of the roll segment; specific means for varying the gap after each full stroke of the roll segment or after a series of strokes, the gap being varied in equal or unequal amounts; a machine in which the roll segment cooperates with a counter-tool in combination with means for feeding metal thereto whose feeding rates are adjusted to the variations of the gap, and/or means for varying the gap.

The invention further relates to a stretching machine for reducing the wall thickness of articles of rectangular cross section in which sections of the article are increment by increment advanced on a plane, which forms an angle with the stretching plane, and subsequently spread out .by a reciprocating tool whereby the wall thickness of the article is reduced.

One of the main features of the invention resides in the provision of a roll segment rotatably mounted on and supported on its entire length against a slide which can be reciprocated by any suitable means, and a countertool provided with the feeding and stretching plane. The roll segment when reciprocated by the slide is unrolling on the counter-tool thereby reducing the wall thickness of the section of the article advanced on the counter-tool.

Prior to the present invention, a reciprocating prismatic tool guided in a press frame has been used, but this has the disadvantage of heavy friction strain exerted by and on the tool. Since in the stretching method very high reduction rates-in excess of 80 per centare normally used, the friction strain on and by merely sliding tools is particularly high and when dealing with the stretching of. steel, requires the use of phosphate coating to prevent direct contact between the tool and the metallic surface of the article to be stretched.

When using rolls as stretching tools there is the drawback that they are subjected to heavy strains of flexure, particularly in dealing with the production of bands of great width. As the stretching machine according to the invention is chiefly used for the production of wedge- .shaped strips, crowned rolls as they are used in conven nited States Patent 9 2,726,562 Patented Dec. 13, 1955 great differences in the reduction rates, the strains of fiexure vary within great limits.

When using a roll segment mounted on and supported on its entire length against a reciprocating slide, on the one hand the heavy strains of friction of the merely sliding prismatical tool are avoided, and on the other hand the roll segment can be supported against the slide, and the slide against the rigidly built press frame so that practically no flexure of the roll segment takes place even if strips of large width are worked. 7

As during the return stroke of the roll segment an additional if small reduction would take place resulting in strains of fiexure manifesting themselves in the section of articie between the roll segment and the feeding apparatus, a further feature of the invention resides in the provision of devices adapted to enlarge the gap between the roll segment and the counter-tool during the return stroke of the roll segment so that the latter unrolls without pressure on the section of the article reduced in the foregoing forward stroke.

As for the production of wedge-shaped strips the gap between the roll segment and counter-tool has to be enlarged or diminished after each full stroke of the roll segment, a further feature of the invention consists in the provision of devices adapted to enlarge or to diminish the gap between the roll segment and the counter-tool after each full stroke or a series of full strokes. Such devices are advantageously combined with those provided for the enlarging of the gap during the return stroke of the roll segment. I

Wedge-shaped strips or sheets cannot be produced in endless lengths like conventional strips and sheets of uniform wall thickness. Tapered strips or sheets as used in aircraft industry must have not only the desired taper but also the exact lengths. This requires a careful planning of the stretching operation. The only practical way to produce any exact taper and length of a tapered strip or sheet is to keep the lengths of stretched sections invariable. This may be illustrated by the following example:

A wedge-shaped strip is to be produced out of a band having a wall thickness of 5 mms. Such tapered strip shall have a length of 5 meters and is to be 1 mm. thick at the one end, 5 mms. thick at the other end. The stretched section shall have a length of 10 mms. 500 revolutions ofthe crank will then be necessary to produce the tapered strip of 5 meters length. Beginning with highest reduction rates the band is to be advanced by 2 mms. After the first stretching operation the gap is enlarged by 4 -DOS mm.

As is to be easily understood, when keeping the feeding rates invariable, already the length of the second stretched section would turn smaller by about .08 mm. and the following sections would turn smaller and smaller, the last section having a wall thickness of and a length of 2 mms.

The thus produced wedge-shaped strip or sheet would have neither the required taper nor the required length. In order to obtain tapered strips and sheets having not only the desired taper but also the exact length, according to the invention, devices are provided by means of which the feeding rates are automatically adjusted to the then existing reduction rates; for instance when dealing with the production of strips of increasing wall thickness such devices are to gradually enlarge the feeding rates so that the length of the stretched sections remain equal mms. =5 mms.

through the whole length of the wedge-shaped article.

Other objects and features of our invention will become apparent from a reading of the following specification in the light of the accompanying drawings, in which Fig. 1 is a front elevation of the apparatus seen from the side where the article to be stretched is introduced;

Figure 2 is a sectional view in line AA of Fig. 1;

Figure 3 is a front elevation of the stretching machine seen from the side where the finished article leaves the machine, the right half of the figure showing a sectional view in line BB of Fig. 4;

Figure 4 is a side elevation of the machine seen from the side where the gap regulating devices are arranged;

Figure 5 is a sectional view in line CC of Fig. 3;

Figure 6 shows details of the devices for lifting the upper feeding roll;

Figure 7 is a sectional view in line DD of Fig. 4;

Figure 8 is a sectional view in line EE of Fig. 7;

Figure 9 is a sectional view in line FF of Fig. 7;

Figure 10 is a sectional view in line GG of Fig. 1;

Figure 11 is a sectional view in line HH of Fig. 1;

Fig. 12 shows a schematic assembly of the devices for automatically varying the feed rates;

Fig. 13 demonstrates the various timing and relationship of the cams in operation.

Mounted in the press frame 1 the intermediate shaft 2 drives a crank shaft 5 by means of pairs of toothed wheels 3, 4 and 3', 4'. The fork-shaped connecting rods 6 and 6 are linked to the toggle-levers 8, 8a and 8', 8a by means of the journals 7, 7'. The toggle-lever arms 8 and 8' are supported against the press frame by means of the journals 9 and 9'. The toggle-lever arms 8a and 8a are connected with the slide 12 by means of the journal 10 which slide is reciprocated by the crank drive through the intermediary of the toggle-levers 8, 8a and and 8', 8a. The slide 12 and the journal 10 are suspended on the press frame by lateral guiding plates 11 and 11' (Fig. 3). The roll segment 14 is linked (Fig. 3) to the journal 10 by means of the lateral guide plates 13, 13'. As is to be seen from Fig. 5 the guide plates 13, 13' are geared with the racks 15, 15 which, at their ends, are held in adjustable proper positions by screws and springs. This device is necessary to hold the roll segment 14 in its proper working position.

The counter-tool 16 rests on the spindles 17, 17 which can be lifted and lowered by rotating the respective cylinder nuts 18, 18' and is provided with a feeding plane which forms an angle with the stretching plane. This angle which may be varied within broad limits has a twofold purpose. plane as the stretching plane, it would not be possible to advance the work piece. The second point is that the deformation of the work piece is considerably facilitated due to the fact that by arranging the feeding surface at an angle to the stretching surface the greater part of the increment to be stretched lies beyond the plane formed by the surface of the finished work piece, the result of which is that stretching consists mainly in pushing such greater part of the increment in the direction in which the stretching takes place and that such component of deformation as tends to press the increment on the countertool is very small compared with other metal forming processes. p

In order to lower the counter-tool during the return stroke and to lift it again after the return stroke is finished as well as to vary the gap between the roll segment and the counter-tool after each full stroke, the following devices are used.

To the toothed wheel 4 (Fig. 4) a grooved cam 19 is secured in which the roll 20 mounted to the end of the bell-crank 21 is guided. This bell-crank is rotatably mounted on a journal in the press frame and with its shorter arm linked to the head piece 22. Rotatably mounted in the head piece (Fig. 7) is the regulating spindle 23 which is screwed in the hollow rack 24. This With a feeding plane lying in the same connected with the lever 22c. strokeof the head piece 22 the free wheel clutches 22d rack is held in engagement with the toothed wheel 25 mounted on the shaft 26 by means of the supporting pulley 24a and the guiding disks 25a and 25b.

On shaft 26 are mounted the worms 27, 27' which are in engagement with the worm wheels 28, 28' secured to the cylinder nuts 18, 18'.

By means of the above described devices the countertool is lifted or lowered only temporarily within a part of the full stroke but there is no change of the gap between the roll segment and the counter-tool between one full stroke and the next full stroke. When dealing with the production of wedge-shaped articles which requires increasing or diminishing the gap after each full stroke the following additional devices may be combined with the above described ones, such devices being shown in an enlarged scale in Figs. 7 to 9.

Rotatably mounted in the head piece 22 is a worm 22a which is in engagement with a worm wheel secured to the upper end of the regulating spindle 23. An extension of the worm 22a carries the fixed box 22b on which the lever 22c is rotatably mounted. In order to couple the lever 22c with the worm 22a, freewheel clutches 22d and 22d are provided the motions of rotation of which free wheel clutches being opposite to each other. The inner races 22c, 22c of the free wheel clutches are rigidly mounted on box 22b whilst the outer races 22], 22 are provided with a fine gearing 22g. A clamping piece 22h correspondingly geared and slidably mounted on the lever 22c can be clamped to one or both free-wheel clutches by means of the screw 22i whereby the outer race of the respective free-wheel clutch is coupled with the lever 220. The joint piece 22l is rotatably mounted on a box 22k adapted to be slid within a slot of lever 22c. The screw 22m serves to fix the box 22k simultaneously in the slot of the lever 22c and that of the curved piece 22n mounted on the press frame.

The above described device operates as follows:

When the toothed wheel 4 turns in clockwise direction the vertical arm of the lever 21 is moved to the left thereby pushing down the head piece 22, spindle 23, and rack 24. The thus caused rotation of the toothed wheel 25 is transmitted to the shaft 26 and the worms 27, 27 which cause the worm wheels 28, 28' and the cylinder nuts 18, 18 to rotate. Shape and arrangement of the cam 19 on the toothed wheel and motion of rotation of the worms and worm wheels are chosen so that in the beginning of the return stroke of the roll segment the counter-tool is lowered by a small amount and towards the end of the return stroke is lifted either into its previous position or into any new position corresponding to the desired change of the gap. To the latter purpose the above described additional gap regulating devices have to be set to work.

When dealing with the production of articles which as a whole are to be reduced uniformly in wall thickness, or in certain sections of them, the lever 220 is put into its zero position, as shown in Fig. 4 by dotted lines, or the coupling of the free wheel clutches 22d and 22d with the lever 220 should be loosened. No rotation is then imparted to the regulating spindle 23. In the beginning of the return stroke the counter-tool is lowered by a small amount, and, toward the end of the return stroke, is lifted to its previous position. When, however, the lever 22c is turnedvfrom its zero position in anticlockwise direction and fixed in the slot of the lever 22c and that of the curved piece 22!: in any position between the zero position and the position shown in Fig. 4, any downward movement of the head piece results in a rotation of the worm 22a, and as the worm 22a is in engagement with the worm wheel secured to the upper end of the regulating spindle 23, a rotation is imparted to the latter which causes the rack 24 to be lifted or lowered depending on which of the two free wheel clutches 22d and 22d As during the return and 22a" respectively prevent the regulating spindle 23 from being rotated in the reverse direction, the increase or decrease of the gap is preserved for the following forward stroke of the roll segment 14. I

On the crankshaft is mounted the cam 31 (Fig. 1 and Fig. which, through the roll' 31a, controls the joint head 31d mounted by means of the joint piece 31b on the bearing 310 of the press frame 1. To the joint head 31d is secured the push rod 31e which, guided in an eye of the press frame, is linked to the free-wheel clutch 32 by means of the part 31]. The pressure spring 31g being effective between joint head 31d and press frame 1 pushes the roll 31a against the cam 31 as far as it is permitted by the cam 47 yet to be described. Cam 31 is shaped so that the push rod 312 is pushed forward while the roll segment is in its posterior dead point position thereby imparting a motion of rotation to shaft 34 by the intermediary of free-wheel clutch 32 and the clawcoupling 33 which shaft is in engagement with the shaft 34 by the intermediary of the pair of gears 35, 35'. The shafts 34, 34' are connected with the feeding rolls 37, 37 by the jointed couplings 36, 36'. The roll pressure necessary for feeding is effected by the bolts screwed in the bearings 38, 39, and pressure springs 42 being effective between the bearings 38', 39 and the nuts 41 (Fig. 6). In order to introduce the article to be stretched between the feeding rolls, levers 43 are provided which impart a motion of rotation to eccentrics 44 thereby lifting the feeding roll 37 by the intermediary of the cross-rail 45 and the bolts 40.

The gradual changes of the feeding rates are controlled by cam 46 secured to shaft 5 (Fig. 1 and Fig. 11) and cam 47. The cam 46 is in constant contact with the roll 46a arranged in the adjusting head 46b (Fig. 11)

which on its part is pivotally mounted on the bearing 460 of the press frame. Horizontally arranged in the adjusting head 46b is the spindle 46d by means of which the slide 462 can be moved to the left. or to the right. Pivoted in the slide 46a is the one end of the push rod 46 Whilst the other end thereof is rotatably mounted on the lever-like extension 46g of the outer race of the free wheel clutch 46h. By means of the draw spring. 46i the roll 46122 is pressed on the cam 46. The cam 47 is secured to the inner race of the free wheel clutch 46h which race is pivoted on the press frame. The push rod 48 guided in an eye of the press frame 1 is controlled by the roll 48a.

The above described devices operate as follows:

The feeding is actuated in the posterior dead point position of the roll segment by .thecam 31 by the intermediary of the push rod 312, the free-wheel 32 and the claw coupling 33. i

As described above, the roll 31:: is pushed toward the cam 31 by the pressure spring 31g but only as far as it is permitted by the cam 47 which defines the distance between the cam 31 and the roll 31a by the intermediary of the roll 48a mounted on one end of the push rod 48; the other end of the push rod is linked to the outer race of the free wheel clutch 32. The greater the distance between the cam 31 and the roll 31a, the smaller is the angle of rotation imparted by the cam 31 to the outer race of the free wheel clutch 32 by the intermediary of roll 31a, push rod 31a and part 31]. When the cam 47 is rotated, the distance between the roll 31a and the cam 31 will be increased or decreased resulting in a decrease or increase of the angle of rotation of the free wheel clutch 32, which angle of rotation defines the feeding rate.

The intermittent rotation of the cam 47 is effected by the cam 46 which imparts an impulse of rotation to the lever-like extension 46g of the outer race of the free wheel clutch 46h by the intermediary of the roll 46a, adjusting head 46b, and push rod 46 By each impulse of rotation imparted to the lever-like extension 46g of the free wheel clutch 46h, a predetermined angle of rotation will be imparted to the cam 47.

' This angle can be adjusted by means of the slide 460 arranged in the adjusting head 46b, which slide can be shifted from the position shown in Fig. 12 toward the axis of rotation of the adjusting head 46b. In the position of the slide 46c shown in Fig. 12, the maximum of rotation is imparted to the extension 46g race of the free wheel clutch 46h.

' In the diagram of the crank cycle (Fig. 13) a-b denotes the forward stroke and b-a the return stroke of the crank, and c-d the portion of its return stroke during which cam 46 actuates the extension 46g of the outer race of the free wheel clutch 46h. But, of course, the action of cam 46 could occur in any other portion of the crank cycle except the portion during which cam 31 is actuating the feed roll means, andwhich can take place near the dead position of the cycle as, for instance, either toward the end of the return stroke as denoted by e-f or at the beginning of the forward stroke.

The hand wheels 30a, 30a, the worms 29, 29' (Figs. 2 and 3') serve a twofold purpose. On the one hand they are to protect the spindles 17, 17' against rotation when the cylinder nuts are rotated for changing the gap, and on the other hand to accurately regulate the gap in its entire width.

The intermediate shaft 2 that drives the crankshaft 5 is coupled to a motor or other source of power. In Figure 2, the material worked on by the roll segment 14 and counter-tool 16 is shown being fed by the feeding rolls 37 and 37 I claim:

1. A stretching machine having in combination a reciprocating stretching tool member and a counter-tool member mounted'in gap relation thereto, a crank shaft operatively connected to said stretching tool member, a rotat able element mounted on said crank shaft having a camtrack thereon, a bell-crank having a roll member at one end thereof guided in said cam-track and a head piece member linked to its other end and reciprocated thereby, a regulating spindle mounted in said head piece, said mounting causing said regulating spindle to reciprocate with said head piece and including means providing for regulating movement with respect to said head piece, means actuated by said reciprocating movement for creating said regulating movement, a rack member actuated bysaid spindle, and means actuated by movement of the rack member to move the counter-tool member toward and away from the stretching tool member.

' 2. 'A stretching machine having the structure set forth in claim 1 in which the means actuated by the rack member includes a shaft,- worm gear means mounted on the shaft, spindle means supporting the counter-tool member, and cylinder nuts rotatable by the worm gear means and in engagement with the spindle means to raise or lower the same.

3. A stretching machine having a frame, a crankshaft mounted for rotation on said frame, a stretching toolmember reciprocated by the rotation of said crankshaft, a counter-tool member mounted in gap relation to said stretching tool-member, means for feeding metal to be reduced in thickness between said members, means for actuating the feed means in accordance with the reciprocation of the stretching member, said latter means including a cam on the crankshaft, a joint head mounted in proximity to said cam, a roller carried by said joint head, a push rod carried by said joint head, a free wheel clutch linked to the push rod, a claw-coupling wheel coupling the free wheel; and means for gradually changing the rate of feed including an element rotatable with the crankshaft, an adjusting head mounted in proximity to said element, a roller on said adjusting head, a slide movable on said adjusting head, a push rod pivoted to one end of the slide, means rotatably mounted on the other end of the push rod comprising a lever-like exten-' of the outer sion of an outer'race of another free wheel clutch,- a cam secured to the inner ring of the last named free wheel clutch, a roll rotatably mounted in contact with the cam, and a push rod connecting the roll and the first named free wheel clutch.

4. A stretching machine having a frame, a crankshaft mounted for rotation on said frame, a stretching toolmember reciprocated by the rotation of said crankshaft, a counter-tool member mounted in gap relation to said stretching tool-member, roll means for feeding metal between said members, means for actuating the roll means in accordance with the rotation of the crankshaft, said latter means including a cam on the crankshaft, a joint head mounted in proximity to said cam, a roller carried by the joint head, a push rod carried by the joint head, a free wheel clutch, means linking the free wheel clutch to the push rod, a claw coupling engageable with the free wheel clutch, shaft means connected to the claw coupling, and means connecting the last named shaft means with the roll means.

5. The stretching machine set forth in claim 4 having in combination with the feed roll means; means for introducing between the feed roll means the material to be fed to the stretching tool including lever means, eccentric means rotatable by said lever means, means movable by the eccentric means to lift the feed roll means; and means for providing feed roll pressure necessary for feeding.

6. A stretching machine having a stretching tool member and a counter-tool member mounted in gap relation thereto, a crankshaft operatively connected to said stretching tool member, feed roll means for feeding metal to be stretched by said members, means comprising a cam rotatable with the crankshaft, means responsive to the motion of the cam member for actuating the feed roll means, additional means actuated by the crankshaft for gradually changing the rate of feed, and other means actuated by the crankshaft controlling the motion of the counter-tool member toward and away from the stretching tool member.

7. A stretching machine for reducing the wall thick ness of articles of rectangular cross section comprising a frame, a slide member arranged adjacent to and supported against said frame, a journal arranged adjacent to and supported against said slide, a roll segment connected with said journal by lateral guide plates and supported on its entire length against said journal, a crankshaft operatively connected with said slide member, a counter-tool having a feeding surface forming an angle with the stretching surface, said counter-tool being mounted in gap relation to said roll segment, feed roll means for feeding metal to be stretchedbetween said roll segment and counter-tool, acam rotatable with the crankshaft, means responsive to the motion of the cam for actuating the feed roll means, additional means actuated by the crankshaft for changing the rate of feed, and

other means actuated by the crankshaft controlling the motion of the counter-tool toward and away from the roll segment.

8. A stretching machine for reducing the wall thickness of articles of rectangular cross section comprising a frame, a slide member suspended on and supported against saidframe, a journal suspended on said frame and'supported against said slide member, a roll segment suspended by means of lateral guide plates on and supported on its entire length against said journal, a crankshaft operatively connected with said slide, a counter-tool having a feeding. and a stretching surface the plane of the feeding surface forming an angle with the stretching surface, said counter-tool being mounted in gap relation with said roll segment; feed roll means for feeding metal to be stretched between said roll segment and counter-tool, a cam rotatable with the crankshaft, means responsive to the motion of the cam for actuating the feed roll means, additional means actuated by the crankshaft for changing the rate'of feed, and other means actuated by the crankshaft controlling the motion of the counter-tool toward and away from the roll segment.

9. A stretching machine having in combination a stretching tool member having a forward stroke and a return stroke, and a counter-tool member mounted in gap relation thereto; means for actuating said first tool member, means for changing the gap in varying amounts including a rotatable element having a cam-track thereon, means for rotating said rotatable element, a bellcrank having a roll member at one end thereof guided in said cam-track and a head piece member linked to its other end and reciprocated thereby, a regulating spindle, means mounting said regulating spindle in said head piece for reciprocating movement in unison therewith and for rotatable movement with respect thereto, means actuated by said regulating spindle to move one of said tool members to change the gap between the stretching tool member and the counter-tool member, worm gear means operatively engaged to said regulating spindle to rotate the same, means operated by the rotation of said spindle to vary the extent of movement of said onemember, a'reg'ulating lever, and means coupling the regulating lever with the worm gear means for regulating the extent of movement of said one member.

References Cited in the file of this patent UNITED STATES PATENTS 748,870 Jones Jan. 5, 1904 1,725,594 Montgomery Aug. 20, 1929 1,890,803 Coe Dec. 13, 1932 2,153,839 Liebergeld Apr. 11, 1939 2,218,460 Singer Oct. 15, 1940 FOREIGN PATENTS 720,076 Germany Apr. 23, 1942

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