US2257253A - Screw threading machine - Google Patents

Description

Sept. 30,1941. w. WIIEMHONERV AL 2,257,253

SCREW THREADING MACHINE Filed June 20, 1958 2 Sheets-Sheet l WWW mvmaq Allomey Patented Sept. 30, 1941 SCREW THREADING MAC 1 Wilhelm Wemhiiner and Werner Piage, Berlin, Gey

Application June 20, 1938, Serial No. 214,733 In Germany June 19, 193? (Granted under the provisions of sec. 14;, act of March 2, 1927; as: o. s. 5)

12 Claims.

Our invention relates to improvements in screw threading machines, and more particularly in machines of the type comprising a pair of externally screw threaded rolie'r dies placed one be side the other and adapted to be.rotated in the same direction for rolling a screw thread into a blank placed between the same. One of the ob- Jects of the improvements is to provide a machine of this type, in which means are provided.

in addition to the said roller dies. for holding the blank being rolled in position. With this object in view our invention consists in provid ing a support between the said roller diesspaced from the plane passing through the axes of said roller dies so far that. the blank is held in position with its axis in or near the said plane. In the preferred construction the said support is located so that the axis of the blank is located slightly below the said plane. We have found that this construction is preferable because thereby it is impossible that the blank being rolled be ejected from between the roller dies by the circumferential forces transmitted thereto by the roller dies.

Our invention also relates to the manner of mounting the roller dies on the frame supporting the same. For insuring exact rolling, the said roller dies must be exactly adjusted in their positions in order that the screw threads of both dies produce exactly corresponding screw threads on the blank'and further the roller dies must be mounted so that they are adapted to be moved under pressure towards each other.

In view of these requirements another object of the improvements is to construct the roller dies and bearings so that they permit such displacements, and with'this object in view another feature of our invention consists in having one of the bearings of the roller dies fixed in position on the frame of the machine while the blank is being rolled, while the other roller die is mounted, together with the shaft carrying the same and the driving gearing, so as to be movable on the said frame in a direction transversely of the axis of the roller dies by hydraulic pressure.

To' permit axial displacement of the roller dies the bearing of one of the said dies is mounted on the frame of the machine so as to be adjustable longitudinally of the axis of the die.

Another object of the improvements is to mount the bearings of the roller dies so that they may be exactly adjusted with their axes parallel to or angularly of each other, and with this obone of the said bearings in the manner of a turn table on a vertical pivot bolt the axis of which passes between the said roller dies.

To permit the said movements of the roller dies, the driven shafts carrying the same are connected with driving shafts disposed perpendicularly to the said driven shafts and parallel to each other, and the said driving shafts are made in telescoping sections permitting the same to be extended or reduced in length, according to the position of the driven shaft and its roller die, and in addition the driving shaft connected with the roller die mounted on the said turn table is constructed for being yieldable transversely of its axis, in accordance with the position of the shaft driven thereby.

By connecting parallel driven shafts with parallel driving shafts the gears connecting the driving and driven shafts are displaced with relation to each other longitudinally of the driving and driven shafts instead of being located one beside the other, so that there is suflicient room to provide strong gearings such as are necessary for transmitting the power from the driving to the driven shafts.

Another object of the improvements is to provide a machine in which excessive axial strains on the driving mechanism of the roller dies are prevented, and with this object in view our invention consists in mounting the said roller dies in their bearings so as to be yieldable in axial direction, the said roller dies-being preferably acted upon by springs.

Other objects of the improvements will appear from the following description.

For the purpose of explaining the invention an example embodying the same I has been shown in the accompanying drawings'in which the same reference characters have been used in all the viewsto indicate corresponding parts. In said drawings:

Fig. 1 is an elevation showing the top part of the machine, 7

Fig. 2 is a plan view of Fig. 1 partly in section,

Fig. 3 is a side elevation of the machine,

Fig. 4 is a sectional elevation taken on the line H of Fig. 2, and

Fig. 5 is an elevation showing a modification of the blank supporting device, the blank being shown in section.

In the example shown in the figures the machine comprises a frame I on which the operaject in view our invention consists in mounting tive parts are mounted. The said operative parts comprise a pair of roller dies 2 and I 10- .to the frame. ed so as to beextensible in accordance with the cated one beside 'the other and formed about their circumferences with similar screw threads, shafts 4 and 5 to which the said rollerdies are secured, shafts 8 and l perpendicular to. the shafts 4 and 5 and connected therewith respectively by worm gearings 8, 9 and II, a pair of gear wheels, l2, [3 connecting the shafts 5 and I, a belt gearing I4; and a motor such as an electromotor. l5 ,for driving the mechanism.

- The said electromotor is mounted on'a bracket l8 secured to the frame Land the gear wheels 3 41 operating an electrical contact 48. included in an electrical circuit controlling the supply of oil,

as will be described hereafter. In lieu of the said cylinder 46 and piston" a contact may be provided in connection with the pressure gauge 45.

The-housing 26- of the shaft 5 is mounted on a plate 55 made, integral with uprights 56 to P which the housing 26 is secured by means of- I2 and I3 are enclosed-within a casing I'I- fixed The shafts 5 and l are constructadjustment of the bearings of the shafts 4 and 5 to be described hereafter. As shown the said shafts 5 and I consist of telescoping-sections connected with each other by keys. Further, the shaft 1 is'capable to yield in transverse dimotion, and for this purpose it includes two universal Joints I8 and I9, 2 showing a Hardy joint. Finally the shaft l-comprises a coupling consisting of a pair of flanges connected by screws 21 passed through circumferential slots made in one of the said flanges.

The shafts 4 and 5 are mounted in substantially cylindrical housings 25 and 26 by means of anti-friction bearings 23 and 21, and the gears 9 and II are mounted on the shafts 4 and 5 so as to permit axial displacement of the'shafts. The zonstruction will be described with reference -to the shaft 4, and it will be understood that-the screws 51, the said screws being passed through slots made in the uprights and permitting ad justment of the housing 26 in the direction of the axis of the shaft 5. The plate 55 is mounted on the'frame I so that it may be turned about a vertical pivot bolt 58 fixed to the frame. For

setting the bed plate in position screws 59 are providedwhich are passed through lugs 68 risin from the frame I, and which engage the plate 55 at points located at opposite sides of the pivot bolt 58. After thussetting the plate 55 it is fixed in position by means of screws 54.

It appears therefore that the housing capable of movements in two directions, first of 1 a movement longitudinal of the. axis of the shaft 5 and second of rotary movement about the pivot mounting of the shaft 5 and the gear II is similar in construction. As shown,.the gear 9- is supported on step bearings 28 and- 29 and it is acted -upon by a, coiled spring 3|! supported on a disk bolt 58. The said axial adjustment permits the rolle'rs 2 and 3 to be adjusted relatively to each other so that the screw-threads formed thereon engage correspondingportions of the surface of the blank on which the screw threads are to be produced by rolling, and the rotary movement of the plate 55 permits the rollers to be placed either with their axes exactly parallel for producing screw threads on cylindrical blanks, or

with their axes at difierent angles for producing 3| fixed to the rear end of the shaft 4. The step bearing 28 is supported on the race rings of. the

anti-friction bearing 23, and the step bearing 29 is normally supported on a shoulder 22 formed within the housing 25. Thespring 30 permits the shaft 4 to yield in axial direction in case ofexcessive axial strain being exerted by the roller die 2. The gear 9 is connected to the shaft 4 by means of a key 32 permitting axial movement of the shaft relatively to the gear.

The housing 25 is secured to or made integral I with a slide 35 which is guided on the frame I transversely of the axis of the shaft 4 by means of guide ways 36, and it is adapted to be shifted in transverse direction for exerting rolling pressure on theblank by means of a pair of hydraulic cylinders 31 fixed to an upright 38 rising from the frame I and containing pistons 39 and piston rods 48 acting on an upright 4| rising from the slide 35. The said cylinders have a supply of oil under pressure, and they are adapted to be retracted, when the supply of oil is interrupted, by means of a spring 42 bearing on the upright 38 and acting on the head 44 of'a screw bolt 34 passed through a hole made in the upright 38 and fixed to a'block 33 made integralwith the slide 35. The head 44 may be provided with a suitable arm projecting towards the upright 38 and adapted for engaging the same as the slide 35 advances, for limiting the movement of the said slide.

.011 under pressure is supplied to the cylinders 31 through pipes 43 by controlling devices which 1 will be described hereafter. For ascertaining the pressure within the cylinders 31a pressure gauge 45 is provided, and for automatically interrupting the supply of oil to the cylinders an electrical control device may be provided which comprises a cylinder 46 containing a spring pressed pistonscrew threads on conical blanks.

The diiierent adjustments of the shafts 4 and 5 require the adjustability of the shafts 5 and I referred to above, and -it-will be understood that the movement of the housing 25 and the shaft] requires onlyv longitudinal adjustment of the-- shaft 6, While the two different adjustments of the housing 26 and the shaft 5 require in addition lateral displacement of the outer end of the shaft I, for which purpose the said universal joints l8 and are provided.

Below the roller dies 2 and 3 a supporting member St is provided which is located with its top face so far belowthe plane passing through the axes of the said roller dies that the blank being rolled, is locatedwith its axis below the plane. Thus in rolling the dies engage the blank somewhat above the horizontal plane passing through the axis ,of the blank, and thereby the r blank cannot be ejected from between the dies by the circumferential forces acting thereon. Preferably the said support is rockingly mounted on a bracket 52 secured to the frame I so that it follows the transverse movement of the right hand roller die 2 as rollingof thescrew threads,

thereof, the said arm being adapted to be passed into'the bore ofthe tubular blank for supporting the same.

In l we have shown a devicefor measuring the depth of the screw threads being rolled.

The said measuring device comprises a measuring instrument 15 having a dial and a hand and mounted at a suitable part of the machine, and a transmission gearing connected with the roller dies. As shown the said gearing consists of arms 16 and 11 rotatably mounted on disks i8 and I9 fixed coaxially to the ends of the roller'dies, a link 80 connecting the said arms at their bottom ends, a link 8| connecting the arm 11 with a relatively fixed part 82 of the plate 55, an arm $3 jointed to the arm "il, a link 86 connecting the arm 83 with the arm 16', a spring 85 intermediate the said arms 83 and i6 and preventing lost motion'in the joints of the arms 83 and it, and a rod 86 connecting the arm 83 with the mechanism of the measuring instrument 35. at the top. end of the arm 83 an insulated contact Bl is provided which cooperates with a contact screw 88 carried by the arm ll, the insulated contact 3? being connected by a lead as with the electromagnet it.

When the roller die 2 is advanced by the slide 35 towards the roller die 3 for rolling the threads on the blank the arm l? is held in position by the link 8|, while the arm it is turned with its top end to the left, and this movement is transmitted through the link as and the rod 85 to the measuring instrument 75 which therefore indicates the advance of the rolling operation. When the insulated contact 81 makes contact with the screw 88 the electric circuit of the electromagnet I is closed through the lead 89 and through the body of the machine, so that the supply of oil to the cylinders 37 is interrupted. By means oi' the contact screw 88 the apparatus maybe set in accordance with the inner diameter of the screw threads to be rolled on the blank.

The operation of the machine is as follows:

The blank to be threaded is placed between the roller dies Z and 3, and the said roller dies are advanced towards each other so as to loosely engage the said blank. The housing 26 is adJusted on the bed plate 55 by loosening the screws 51, shifting the housing on the bed plate axially of the roller dies and again fixing the same in position by means of the screws 51. Exact adjustment of the screw threads relatively to each other is obtained by disconnecting the disks 20 of the shaft 1 and turning the same relatively to each other, the said rotary movement being 7 transmitted through the shaft to the roller die 3. The angular position of the roller dies is adjusted by loosening-the screws 54 and turning the bed plate 55 about its pivot bolt 58, the bed plate being finally fixed in position by means of the screws 54.

After the operative parts of the machine have thus been-adjusted oil under pressure is admitted to the cylinders 31 by opening the valve controlled by the lever 00, the pressure of'the oil within the cylinders I} being gradually increased. Simultaneously the electromotor I5 is switched in for imparting rotary movement to the roller dies 2 and I. As the roller die 2 is advanced towards the die 3 the hand of the messuring instrument l5 advances, thus showing the advanceof the rolling operation. .Finally the insulated contact 81 engages the screw contact ll. thus energizing the electromagnet Ill and interrupting the transverse movement of the roller die'2. v

The supply of pressure to the cylinders I! is controlled by means of a valve chest 85 having a supply of oil under pressure through a pipe 6 6' and connected with the aforesaid oil supply pipes 43 to the cylinders 31. Within the valve chest a valve is located which is operated by means of a hand lever 68 and a rod 89; Further, the said valve may be closed independently of the rod 69 by means of an electromagnet 10 acting on a lever ii, the said electromagnet being energized through leads 12 including the aforesaid contact 88.

We cl:

1. In a screw threading machine, comprising a pair of roller dies placed one beside the other in position for receiving a blank between the same, shafts on which said roller dies are mounted, common driving means for said shafts, and driving connections between said driving means and each of said shafts, the improvement herein described which consists in a separable coupling arranged in the connection between the driving means and one of said shafts, said coupling when disengaged permitting the rotation in circumferential adjustment stone of the said roller dies relatively to the other.

2. In a screw threading machine, comprising a frame, a pair of roller dies mounted on said frame one beside the other in position for receiving a blank between the same, and bearings for said roller dies mounted on said frame, the bearings of one of said dies being movable transversely of the axes of said roller dies, the improvement herein described which consists in hydraulic means for automatically moving the bearings of one of said dies towardthe axial line of the companion die as the thread-cutting progresses, and for holding the die under pressure to the work throughout the thread-cutting operation, and means for controlling the hydraulic pressure acting on said bearing.

3. In a screw threading machine, comprising a frame, a pair of roller dies placed one beside the other and adapted to receive a blank between the same, bearings for said roller dies, means for forcing the bearings of the dies severally towards each other, and driving means for said shafts, the improvement herein described which consists in a table mounted on said frame and supporting the bearings of one of said dies, said table having pivotal movement about an axis perpendicular to the common axial plane of the said dies and passing between the said roller dies, whereby the position of the table and of the bearings borne thereby may be adjusted, and means for securing said table in adjusted position on said frame.

4. In a screw-threading machine comprising a pair of roller dies placed one beside the other and adapted to have a blank placed between them. means for rotating said roller dies, and means for forcing said roller dies toward each other for exerting rolling pressure on said blank, the improvement herein described which consists in indicating means connected with said roller dies and adapted to indicate the distance between the axes thereof, the said indicating means being in the form of links arranged substantially in the form of a parallelogram, two

opposing links being rotatably mounted on the axis of said roller dies, an arm pivotally mounted on one of said links mounted on said roller 4 hydraulic means for forcing said roller diestowards each other for exerting rolling pressure on said blank, a valve controlling the supplyoi pressure fluid to said hydraulic means, and electrical means controlled by said roller dies adapted to close said valve when theroller dies have been advanced towards each other to a predetermined distance. I i

6. In a screw-threading machine that includes a pair of roller dies formed with external screw threads and adapted to receive between them a blank to be threaded, and means for rotating the dies, the improvement herein described that consists in means for holding one of the rotating dies to engagement upon an introduced blank yieldingly and under thread cutting pressure, and means efiective on the relief of such pressure for retracting said die. I

7. In a screw-threading machine that includes a pair of roller dies formed with external screw threads, arranged in parallelism, and adapted to receive between them a blank to bethreaded, means for rotating the dies, and means for advanoing one of the dies toward the other as operjation progresses, the improvement that cohsists in a support adapted to hold a blank to position to be operated upon by said dies, the support being movable in a directiontransverse to the axes of the roller dies.-v

8. In a screw-threading machine that includes tal base-plate, a slide mounted upon said baseherein described which consists of two home by the bearings severally of the two a pair of roller dies formed with external screw threads, arranged in parallelism, and adapted to receive between them a blank to be threaded, means for rotating the dies, and means for advancingone of thedies toward the other as operation progresses, the improvement that consists in a support adapted to hold a blank to-position to be operated on by-said dies, the support being pivotally mounted on an axis parallel to the axes of the roller dies. v

19, Ina screw-threading machine that includes a ipair of roller dies formed with external screw threads, arranged in parallelism, and adapted to' thereby, and means for advancing the said slid plate, a housing borne by the slide, a threaded die rotatably mounted on a horizontal axis in the housing, a plate borne by said base-plate and rotatable upon a vertical axis, a housing mounted upon said rotatable plate and a threaded die rotatably mounted on a horizontal axis in the ofsaid rotatableplate, the. housing mounted upon said rotatable plate being adjustable in the direction of the axial extent of the die borne and holding the die borne thereby yielly under pressure .to engagement with ablattroduced between the said die and its compare ion die. v

11. In a screw-threading machine pair of roller dies mounte in t V at means for causing the dies togethe with their several ,bearings to advance one relatively to the other under pressure upon a blankintroduced between them, as, in the course oi operation they sink a thread in the blank, the improvement inclu 1'. a dies and radially extending from the bearings with reference to the axes of die rotation, link con nection between the two arms, whereby relative movement of the bearings oi the two dies efiects variation in the angular positions of the a relatively one to the other, and a measuring de vice responsive to variation in such angular positions of the two said arms.

12. In a screw-threading machine comprising a pairof roller dies placed one beside the other and adapted to receive a blank between the same, bearings for said roller dies, and driving means for said roller dies, and means for forcing said roller dies towards each other, the improvement herein described which consists in a pair of housings one for each die within which the dies are severally mounted for movement both rotatively and longitudinally in axial direction, and the driving means including a gear borne by the die and supported on va-step bearing within the.

housing and restrained thereby from movement in the direction of the-axis of the die, the die and the gear being relatively movable in-the di-

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