DE2200294A1 - Tapping machine - Google Patents

Description

qu Munich-Pullach, January 3, 1972

AERPAT AG, Alpenstrasse 14, CH 6301 Zug , Ichweiz

Tapping machine

The invention relates to a machine zui .; Drilling screw threads in workpieces, and more particularly, the invention relates to a tapping machine and one used therein Taps.

Two types of taps are commonly used, namely the tap and the tap. Taps Both types are in the form of a component provided with a screw thread on the outside, which in a suitable size hole is inserted in a workpiece while the workpiece and the tap are relative to one another to be turned around. In the case of the tap drill, the screw thread on the surface thereof is ordinary interrupted by two or more longitudinal grooves which form cutting edges, while in the case of thread rolling drills the screw thread is continuous and is formed on a portion of the shaft which has a lobed Has cross section, usually three or four such tabs are provided. A tap drill forms a complementary screw thread in the workpiece

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by making a part of the workpiece for forming a groove or grooves are cut out and a thread rolling drill forms a complementary screw thread through the material of the workpiece is displaced. The use of cutting drills is consequently accompanied by the generation of chips which the thread cutting process and the operation of thread cutting machines, in which thread cutters are used, can have an unfavorable effect. The thread rolling drills, on the other hand have the advantage that they produce little or no chips.

A form of cutting drill that is commonly used, particularly in continuous threading machines, is known as an "overflow drill" or "curved shank tap" and is in the form of a rod-like shape Part which has a thread cutting section in the area of one end and the remaining part of which forms a shaft, which is bent by a radius which is larger than the diameter of the shaft and which is bent by an angle of approximately Is bent 30 to 180 ° and usually 90 °. The outside diameter of the shank is smaller than the minimum inner diameter of the screw thread, which the tap cuts so that the shank can pass freely through a hole made through the cutting portion of the tap has been threaded.

Overflow drills are used in thread cutting machines where they are loosely mounted while they are related to the The blank in which a thread is to be cut can be turned. The tapping section of the tap first enters the blank and runs through it, forms a thread and is held by the narrow shaft of the

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Tap followed. The arrangement is such that the tap is held stationary while the blanks are pushed onto the tap and rotated and themselves move along the tap and fall off the shank at the end remote from the tapping section. The assembly of the taps is such that the curved shank is used as a lever to prevent the tap from rotating to withstand when this in frictional Comes into engagement with the rotating workpiece. The arrangement allows the blanks to be more or less continuous Sequence applied to the tapping end of the tap and after tapping from the other End of the tap can be removed. A comparatively high output of threaded blanks is thereby possible.

Despite the well-known use of thread cutting drills with a curved shank, it was not known before the present invention, a thread rolling drill with a curved Shank to use. Consequently, when using thread tapping drills, it was always necessary to use the tap withdraw from a workpiece in the direction opposite to that in which it enters the workpiece was advanced to form a thread.

According to one proposal of the invention, a thread rolling drill is used provided the one gauge rolling part suitable for forming a screw thread in a workpiece and a curved shaft with an outside diameter smaller than the minimum diameter of the thread formed by the threaded part.

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The tapping portion of the tapping drill can be of any conventional shape, but under certain circumstances it becomes Preferred type that has an even number of lobes.

The shaft can be bent in an arc of a circle, which ' has a diameter which is at least as large as the diameter of the shaft. The angle at which the stem is bent off the axis of the Gev / indebohrteiles can be in the range of about 20 ° to 180 °. The shaft can be turned off at one or more points. The smallest bend radius the or each of the bends must depend on the size and shape of the workpieces that must run along the tap and can be multiple be larger than the diameter of the shaft.

According to a further proposal of the invention Wr a thread cutting machine d created, which has a workpiece-holding device, which is alternatively operable to close and thereby to hold a workpiece and to open and thereby release the workpiece and which has a tapping attachment, whereby the The workpiece holding device and the tapping device are continuously rotatable relative to one another about an axis and can be reciprocated relative to one another along this axis in order to move the tapping device in the direction of the holding device and to drill a thread in a workpiece held by the holding device and to remove the tapping device from the Holding device move away to thereby remove the workpiece provided with the thread ver from the holding device, and with feed devices for maintaining a continuous supply of workpieces to the workpiece holding device voijfeiner from the tapping device distant side

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te her, the tapping device with respect to the holding device can be moved back and forth in a timed relationship with the opening and closing of the workpiece holding device is.

The tap forming the thread can be a tapping drill with a bent shank of the type defined above.

The feed devices can have means which form an elongated passage which is suitable for carrying workpieces and which is arranged such that the workpieces through the passage under the action of gravity to the holding device be brought down. The means defining the passage can consist of a tube. The pipe can have a shape have that there is a substantially horizontal section which opens in the region of the holding device and shows a vertical section arranged to form a kind of pressure column on workpieces.

In the following, the invention is explained in more detail with the aid of some embodiments illustrated by way of example in the drawings explained. It shows:

Figure 1 is a side view of the thread rolling drill after .der present invention;

FIG. 2 shows a section along the line II-II from FIG. 1;

FIG. 3 shows a schematic interior view of an automatic thread drilling machine according to the present invention;

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FIG. 4 is a plan view of part of that illustrated in FIG Machine;

FIG. 5 is a somewhat schematic, partially sectioned view of part of that illustrated in FIG Machine illustrating the arrangement of parts of the machine in an operating stage;

Figures 6, 7 and 8 are views similar to Figure 5, illustrating the positions of the parts of the machine in successive stages of operation;

Figure 9 is an end view taken along line IX-IX of Figures 5 and 7

Figure 10 is a sketchy view of one in the machine

control device used according to Figures 3 to 9.

The thread rolling drill 10 illustrated in FIGS. 1 and 2 is designed in the form of an elongated part which is produced from hardened tool steel. A portion 12 of the part in the region of one end is suitable for forming a screw thread in a corresponding workpiece and is hereinafter referred to as the tapping portion. The remaining part of the structure between the tapping section and the other end forms an elongated shaft 14.

The shaft 14 has a circular cross-section and a substantially constant diameter over its entire length and is angled or angled by an angle of 90 ° around a radius of approx. 5 cm on a stele 16

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gen, which in its length at a distance from the tapping section which is approximately equal to the length of the tapping section.

The tapping portion 12 is in the usual manner as four-lobed roller drill formed. That is, its cross-sectional shape is essentially that of a rectangle whose sides are slightly rounded inwards towards the corners, so that the corners are almost completely rounded, wherein each corner area forms a tab 18. A screw thread 20 replaces itself completely around the outer circumference and over the length of the tapping section.

The outside diameter of the shank 14 of the tap is smaller than the maximum root diameter d of the screw thread on the tapping portion 12.

The thread rolling drill 10 according to the present invention can be modified in that the tapping section is formed with three or five lobes instead of four lobes by shaping the cross-section into a substantially triangular or pentagonal shape two lobes formed, the basic cross-sectional shape being essentially elliptical.

A high-speed automatic tapping machine, which may have either a tap according to the present invention or a conventional overflow tap with a bent shank, is described below with reference to FIGS.

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The machine is built on a frame 30 and consists of a rotatable chuck 32, blank feeders 34 for Infeed of workpieces (hereinafter also referred to as "blanks" referred to) on one side of the chuck 32 and a thread rolling drill 10 with a bent shank, which is connected to the lower With reference to Figures 1 and 2 described drill is identical, this tap in the direction of the axis of rotation of the feed on the one remote from the feeder Side of the chuck is arranged to be reciprocable in the longitudinal direction. In the embodiment described is the axis of rotation of the chuck is horizontal, but it is obvious that this axis can be perpendicular or oblique.

As can be seen from FIGS. 5 and 9, the chuck 32 is of the usual construction and has three jaws 3b which are arranged in a circular housing 38 which is rotatably mounted in bearings in the machine frame and also an actuating sleeve 40 for opening and closing the cheeks. The chuck is open-ended so that successive blanks 54a, 54b, 54c, 54d (see FIGS. 5 to 8) can enter from the feed device 34 at one end and leave the chuck at the other end facing the tap. The chuck is driven to rotate at variable speeds of up to approximately 5,000 revolutions / min.

The jaws 36 are designed to be resilient in the direction of the open position and their gripping surfaces show useful profiles in order to match the outer profile of the blanks to be provided with the thread. The radially outer surfaces of the jaws are beveled to interact with the actuating sleeve 40, which rotates with the jaws and the longitudinal

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the axis of rotation of the chuck is movable. In the view of the drawings, a movement of the actuating sleeve follows on the right the jaws, around a blank arranged between the jaws and a movement to the left likewise in the view of the drawings allows the jaws to be opened under the action of the spring.

The chuck 32 is assigned a stop 42 which can be moved into and out of a working position in which it prevents one fed into the feed by the feeder The blank leaves the chuck immediately. The AnscMqg 42 is in Forir. formed of a blade or slide, which is mounted on a stop shaft 44, which is through an angle is pivotable by 90 ° and is designed such that it closes the jaws of the chuck at the end of the chuck that closer to the tap. A pivoting movement of the stop shaft moves the stop in a direction perpendicular to the Axis of rotation of the chuck lying direction in and out of the working position, in which the stop extends over part of the circular Opening formed in the chuck when the jaws are in the open position.

The feed devices 34 for the blanks consist of a feed pipe 45 which is at an angle of 90 ° around a radius is bent, which is very large in comparison with the inner diameter of the pipe. The tube 45 is arranged such that it has a vertical leg 46 and a horizontal leg 48 and is held by clips 50. The horizontal leg 48 of the feed tube extends The jaws of the chuck are free through the actuating sleeve 40 until almost in contact with the jaws, while the vertical upright leg 46 extends upward for a distance,

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which is sufficient to achieve an appropriate pressure height above the To create feed and leads to a feed hopper 52. The feed funnel 52 is of the usual construction Vibrating bowl which can hold a supply of tubular blanks and which holds the blanks in the vertical Introduces legs of the feed tube 45 aligned. The hole diameter of the feed tube 45 is of such a size that the blanks in a single row and in the same orientation be held with aligned holes.

The blanks 54, which are illustrated in particular as a sequence of blanks 5 ^ b, 54c and 5 * + d in Figures 5 to 8, are only conveyed from the feed hopper to the feed under the action of gravity. It is obvious that devices may be provided to support the passage of the blanks through the horizontal leg, the may be formed by mechanical devices or a stream or blower of gas. However, it turned out that it is possible to use only gravity for this purpose, provided that it is sufficient Pressure head of blanks in the pipe is maintained. The height of the perpendicular leg 46 and the The feed speed or amount through the feed hopper are set accordingly.

If the axis of rotation of the chuck is inclined between the horizontal and the vertical, the lower leg of the feed pipe is inclined accordingly instead of the horizontal arrangement described. In the case of a vertical or very steeply inclined axis of rotation of the chuck, the feed pipe can consist of a straight pipe, which is directly from the Feed hopper leads to the feed along the axis of rotation of the feed.

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Since the friction between the blanks and the inner wall of the feed tube can be an important factor, the tube is made of a material which has a comparatively low coefficient of friction with respect to the blanks. In the described embodiment of the invention, the tube ki> Conveniently, made of nylon, which due to its transparency, visually inspect the progress of the chain of blanks permit ^, but other metals or Plastikmaterialfen also with satisfactory results usable.

In accordance with a well known practice of using overflow taps in thread cutting machines, the tap 10 is held by the drill holder 56 and is held in precise position in the holder by a number of blanks. Thus, before the machine is operated, a number of the blanks are pushed into the part of the shank in the tap holder. This condition is usually achieved by leaving the blanks in place on the tap after a previous manufacturing process has been completed.

The thread tap holder 56 holds the tap 10 with its tap portion 12 facing the chuck 32 and aligned with the axis of rotation of the chuck. The drill holder is mounted on a slide 58 , which is parallel to the axis of rotation of the chuck reciprocable on a slide 60 which is formed on the machine frame so that the tap can be advanced in the direction of the chuck to pass through the To enable the tapping section of the tap through a blank held in the jaws of the chuck and together with a

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Winding blank can be withdrawn from the chuck.

The frame accommodates (not shown) an electric motor, wherein the chuck 32, the carriage 58, the Backenbetätigungsh ^r Ilse 40 and drives the stop 42nd

The chuck is driven to the engine via an expedient Gear (not shown) connected. The drive from the motor is also via a coupling (not shown) and a transmission which includes a carriage cam 62, a stop shaft cam 64, and an actuator sleeve cam 66 (all schematically indicated in Figures 3 and 4) connected, which control the movements of the carriage, the stop and the bridge actuation sleeve in such a way as to achieve a create coordinated movement between these parts. By means of the clutch it is possible to have the coordinated movement of the slide, the actuating sleeve and the stop regardless of the chuck, which rotates continuously as long as the motor is running, stopping or restarting.

The movement of the carriage, the stop and the actuating sleeve are coordinated so that the following sequence of Steps can take place during the tapping of the successive blanks, with four stages of the process in Figures 5 to 8 are illustrated.

At the beginning of the work sequence (in the view according to FIG. 5) the chuck 32 rotates, the actuating sleeve 40 is after withdrawn to the left so that the jaws 36 are open, the stop 42 is in the working position and partially covers the outlet opening of the chuck and the carriage 58 is

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withdrawn to the right so that the tap 10 of the Lining is removed. The feed tube 45 is of course more tubular to a convenient height with a column Blanks filled and because of the pressure head formed by the column, the leading blank 54a of the column was made pushed out the feed tube into position between the open jaws of the chuck. The stop prevents the front lying blank is pushed directly through the chuck. This state is illustrated in FIG.

The actuating sleeve 40 now begins to move to the right, to close the jaws and at the same time the slide 58 begins moving to the left to the tap 10 to advance in the direction of the blank 54a held in the chuck. When the jaws are closed over the blank at the front in order to hold it in place, the stop shaft is rotated 90 ° and thereby pulls the stop into it Non-work situation back. This stage is illustrated in FIG.

The leftward movement of the carriage pushes the tap into the bore of the leading tubular Blank 54a, which is held in the chuck and rotates with this, so that the tap is threaded in the Bore of the blank forms. The tap advances its feed until the total length of its tapping section has passed through the blank so that a now threaded blank 54a with a free space around the shank of the tap is rotated. After the tapping portion of the tap over the leading blank 54a has run out, he is at the ready with the next

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The following blank 5Ab has come along and has it along the feed pipe pushed to the left against the pressure of the pressure column of blanks in the pipe and thus creates a gap between the now threaded leading blank 54a and the next following blank 54b. This condition is illustrated in FIG.

The actuator sleeve is then withdrawn to open the jaws of the chuck and around the threaded blank To release 54a, which stops rotating and the carriage begins to move to the left and carry the tap with the threaded blank 54a on its shank with it. Because of the pressure column of blanks in the tube, the column of blanks follows the moving tap, but the threaded tap holds Section of the tap the distance between the threaded blank 54a and the next following blank 54b. Once the threaded blank 54a is moved past the stop, the stop shaft is through 90 rotated back and brings the stop in its working position so that it between the threaded blank 54a and the advancing next following blank 54b comes to rest. While the sled his to the right Continuing movement that has been followed by the column of blanks, the next following blank 54b enters the chuck and finally comes into engagement with the stop which prevents further forward movement of the column of blanks. The carriage continues to move to the right until the tap sweetly engages the next following blank 54b comes. This state is illustrated in FIG.

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Now the machine begins the next work cycle, whereby moves the actuator sleeve to the right, closes the jaws around the following blank 54b in the chuck, and the carriage begins to move towards the feed. As soon as the jaws of the chuck have gripped the next following blank 54b, the stop shaft rotates around the stop in its Non-working position to move. The tap is advanced into and through the bore of the next following blank 54b, drills a thread and the blank 54b gets onto the shank of the tap and pushes the originally leading one Blank 54a in front of you. During each subsequent blank, i.e. blanks 54c, 54d, onto the shank of the tap get, they displace one of the previously threaded blank, which then in, any expedient manner can be caught.

If it is now desired to temporarily interrupt the tapping process, this can be done by only the The clutch is disengaged, thereby stopping the carriage from reciprocating while the chuck continues can turn. It will be apparent, however, that if the chuck is stopped while the tap is in engagement with the rotating workpiece, the tap would be broken off. This difficulty is avoided by Control means are provided for controlling the clutch in such a way as to ensure that the Sled only stops when it is at or within a specified distance from the limits of its reciprocating motion is located so that the tapping portion of the tap has either completely traversed the workpiece or from the last threaded workpiece from the chuck is completely withdrawn and not yet engaged

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with the next workpiece in which a joint is formed is to be reached.

The control device of this embodiment is illustrated schematically in FIG. 10 and has a pneumatic lifting device 70 which can be actuated to disengage the clutch (reference number 72) through which the drive is transmitted to the slide. The lifting device 70 is actuated by compressed air which is passed at constant pressure from a source 7h through a supply line 76 which is equipped with two normally closed valves 78,80.

A trigger 82 is arranged on the rotatable camshaft which carries the slide cam 62 and is designed in such a way that that it opens the valve 78 momentarily each time the camshaft rotates at a time when the slide is from the lining is removed. The valve 80 is actuated by depressing a push button under the control of the operator Machine open.

To stop the reciprocation of the carriage, the operator of the machine opens the valve 80 by depressing the push button for a time sufficient that the trigger 82 reaches a position in which it opens the valve 78th

As soon as the valves 78 and 80 are both open, air flows to the lifting device 70, actuating it to disengage the clutch, whereby the transmission is interrupted and the carriage stops in a position away from the chuck in which the taps are not in Engagement with a blank .

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It will be apparent that the opening of the valve 80 by the machine operator will not be effective to prevent the To stop movement of the carriage until the carriage is in an appropriate position, since only then the Trigger is in position to open valve 78.

The tapping machine of the described embodiment shows a surprising advantage in that an unusual high output of threaded blanks can be achieved, as can be seen from the following details of a actual manufacturing process can be seen.

The machine was used to cut 1/4 "thread into tubular blanks of killed steel over a length of 9/32" drill. The thread rolling drill 10 was one with 14 turns appropriate thread formed over its tapping portion and formed each blank with six turns one Thread turn. Though the common tapping speed for 1/4 "British Standard threads by roll drilling in killed steel, expressed in revolutions / min, approximately is between 400 and 600, the machine was continuously at a drilling speed of 1,700 revolutions / min. operated. An output of 3,600 threaded blanks per hour was achieved and the threads in the with Threaded blanks were of good quality.

In a modified form of the tapping machine described above the stop 42 can be dispensed with, the tap 10 being used to prevent that Blanks pass directly through the open chuck from the feeders when the tap is withdrawn. To enable the tap 10 to perform this function

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When the carriage 58 is satisfied, the reciprocating slide 58 is arranged such that when the slide is fully retracted instead of being a considerable distance from the chuck, the tip of the tap is merely is currently free of the feed, so that a blank can enter the feed from the tube Λ 5, but the feed without the presence of the tap cannot go through. The chuck can then be closed over the blank to be threaded and the instant begins The slide moves in the direction of the chuck, the tap begins to penetrate the blank and dig a hole to drill the blank. It is evident that this modified form is an economical saving of Parts in the construction of the machine made possible and also by the fact that the distance that the carriage takes during its Back and forth movement has been shortened, the duty cycle time can also be shortened.

All of the technical details mentioned in the description and recognizable in the drawings are important for the invention .

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Claims (1)

PATENT CLAIMS J tapping machine for making threaded Workpieces with high output, characterized in that they are in combination with the following Components comprising: workpiece holding devices (32) which are operable to alternatively close and thereby include To hold workpiece (54) and to open, thereby releasing the workpiece (54) and a tapping device (10), wherein the thread holding device (32) and the tapping device (10) continuously rotatable relative to one another about an axis and relative to one another along this axis and are movable back to the Ge \ .indebohreinrichtung (10) in the direction of the holding device (32) for drilling a garment to drill in a workpiece (? 4) held by the holding device (32) and to remove the tapping device (10) from the Retraction device (32) with retraction and supply devices (48, 52) to maintain a continuous supply from workpieces (54) to the workpiece holding device (32) from a side thereof that of the tapping device (10) is removed, the tapping device (10) in timed relationship with the opening and Closing the workpiece holding device (32) can be reciprocated. ■ 2. Tapping machine according to claim 1, characterized in that that the feed means (48, 52) define an elongated passage, the continuous supply of workpieces (54) to be threaded. 209831/0654 3. Tapping machine according to claim 2, characterized in that the feed devices (48, 52) have a tubular part (48) which is designed such that it guides workpieces (54) to the holding devices (32). 4. Tapping machine according to one of the preceding claims, characterized in that the feed device (48) such is designed to maintain a column of pressure on threaded workpieces (54) and that the workpieces (54) are conveyed down to the workpiece holding devices (32) under the action of gravity. 5. Tapping machine according to one of the preceding claims, characterized in that the tapping device (10) a tap (10) with an angled shank, which is arranged so that threaded components longitudinally of the drill (10) and thus leave the machine. 6. Tapping machine according to one of the preceding claims, characterized in that the thread drilling device (10) is a thread rolling drill with an angled shank. 7. Tapping machine according to claim 6, characterized in that the thread rolling drill has a tapping section (42) has a four-lobed cross-section (18). 8. Tapping device with a tapping section, by means of a thread of which can be rolled in a workpiece and with a shank, characterized in that the shank (14) has a diameter smaller than the minimum diameter of the thread passed through the tapping portion is formed and that the shaft (14) is bent at (16). 209831 / 065i 9. Tapping device according to claim 8, characterized in that that the threaded boring section (12) has a lobed cross section. 10. Tapping device according to claim 9, characterized in that that the threaded boring section (12) has an even number of lobes (18). 209831/0654 Blank page