US2054521A

US2054521A - Multiple spindle turret lathe

Info

Publication number: US2054521A
Application number: US23807A
Authority: US
Inventors: Poppensieker Fritz
Original assignee: Individual
Current assignee: Individual
Priority date: 1935-02-13
Filing date: 1935-05-28
Publication date: 1936-09-15
Anticipated expiration: 1953-09-15

Description

Sept. 15, 1936.

F. POPPENSIEKER MULTIPLE SPINDLE TURRET LATHE Filed May 28, 1935 4 Sheets-Sheet 1 In venor:

FRITZ POPPENSIEKEK a; will hi1 (7th rap p 15, 1936. F. POPPENSIEKER 2,054,521

MULTIPLE SPINDLE TURRET LATHE Filed May 28, 1935 4 Sheets-Sheet 2 FRITZ POPPENSIEKER Sept. 15, 1936. F. POPPENSIEKER MULTIPLE SPINDLE TURRET LATHE Filed May 28, 1935 4 Sheets-Sheet 5 rm; POPPENS/EKER Sept. 15, 1936. F. POPPENSIEKER MULTIPLE S PINDLE TURRET LATHE Filed May 28, 1935 4 Sheets-Sheet 4 v Mare/1Z0!" FRITZ PDPPENS/EKER A fifllme U l W H8 Patented Sept. 15, 1936 MULTIPLE SPINDLE TURRET LATHE Fritz Poppensleker, Cologne, Germany Application May 28, 1935, Serial No. 23,807 In Germany February 13, 1935 Claim.

This invention relates to automatic or turret lathes, more particularly to so-called multispindle turret lathes for bar stock having a plurality of spindles.

It is an object of my invention to provide an improved design of such lathes so that the recharging of the guiding device for the bar stock may be effected while the lathe is still running.

Another object is to provide for signals to be automatically given to indicate when certain manipulations in the re-charging of the lathes should be performed.

Still another object is the provision of means whereby at least part of such manipulations are superseded by automatic movements produced by the machine itself and taking place at predetermined stages.

Still further objects will become apparent in the course of the following description.

The introduction of bar material in automatic turret lathes always causes a certain loss of time which, depending on the length of the blanks and on the time required for the actual machining, may amount to a considerable proportion.

In connection with turret lathes having a single spindle it has been proposed to provide apparatus for feeding the bar material into the chuck either automatically or semi-automatically. The type of arrangement used in connection with such single spindle machines cannot, however, be used with multiple spindle turret lathes because the bar guides of multiple spindle lathes must participate in the indexing motion of the spindle drum. Consequently, it has so far been necessary to arrest multiple spindle turret lathes entirely before inserting fresh bars in the bar guides.

The moment when to stop the machine has so far been difficult to ascertain because it must first be ascertained whether all four feeding sleeves have become empty.

According to my present invention the loss of time or idle period involved in introducing fresh bar material in the spindles of multiple spindle turret lathes is reduced by the provision that the bar guides can be stopped while the spindle drums still contain portions of bar material sufficient to keep the lathe running for a. certain further period. During this additional period of running, which is determined by the distance between the disconnectible bar guides and the feeding sleeves of the individual spindles, the bar guides can be re-charged, i. e. fresh bar material can be inserted. In this way the loss of time which is usually connected with this task and which is responsible for the greater part of the total loss of time can now be utilized by keeping the lathe running.

The connectible and disconnectible arrangement of bar guides provided in accordance with my present invention further enables me to effect automatically certain further operations and steps required in the re-charging of a multiple spindle lathe. This has so far been impossible because of the reasons mentioned above. For instance, the disconnection of the bar guides may be effected automatically. The machine can be stopped automatically during the insertion of a bar in the feeding sleeve. The machine can be re-started, and stopped again after the work allotted to one indexing step has been finished. Thus the time of charging becomes substantially independent of the attention and the skill of the attendant and is controlled by the lathe itself. Even if only part of these operations is controlled automatically by the machine itself the advantage remains that the attendant need not leave his position beside the spindle drum and can devote his full. attention to the spindle heads and to the working of the tools. Consequently, he can safely prevent the loose remnants of the bars, which can no longer be gripped by the feeding sleeves, from being hurled about. Otherwise these remnants could easily damage the elaborate and expensive tools.

In order to indicate the instant at which the clutch should be thrown out I may provide for a signal, optical or acoustic, to be given as soon as the longest bar has left the bar guide. The production of the signal may be controlled by the bar itself and may be effected by mechanical, electrical or optical means.

Furthermore, in order to indicate immediately and distinctly the moment at which the longest bar is used up, I may provide for a second signal to be given which is dependent on the first signal, the lag of time being adjustable. This adjustment is effected in accordance with the length of bar required for one job, i. e. depending on the number of jobs or complete revolutions of the drum as compared with the length of the bar lying within the feeding sleeve. Furthermore, the lathe can be stopped simultaneously by the same apparatus in order to prevent any damage by the above mentioned loose bar remnants. This stopping also means a further saving of driving power in case the operator should not pay attention or should not be present.

The loss of time may be further reduced by an arrangement according to which the bars are advanced into the working position by moving ii is rigidly secured to the other end of this bar.

the feeding tube backward and forward by hand in order to slide it over the bar. whereupon the bar is pulled forward. This also prevents the introducing of the bars in Jerks or even knocks and the damage to roller bearings which are otherwise unavoidable.

Even the feeding of the bars through the spindle drum into the working position may be produced automatically if desired. Finally, the repeated staRifi'gs of the machine and the intervening arrestings may be effected automatically until all the bars one after the other have arrived in the working position.

Thus briefly, the reduction of the loss of time may be obtained by the following provisions:-

(1) The bar material is inserted in bar guides which are not indexing during the time the bar portions in the feeding sleeves are being worked (2) The moment when only bar remnants are contained in the open chucks is indicated by a signal or by the machine being arrested.

(3) Damage to tools due to loose bar remnants is prevented.

(4) The machine is arrested automatically each time when the tools and the stop for the material do not prevent the election of the last remnants or end pieces of the bars.

(5) The feeding of the fresh bars into the feeding tube is brought about from a position from which the operator can supervise the working position, thus dispensing with any walking to and fro with attendant loss of time.

In the drawings one way of carrying out my invention is illustrated. i

Fig. 1 is a complete elevation of a multiple spindle turret lathe.

Fig. 2 is a cross section along line A-A in Fig. 1, as seen from the right.

Fig. 3 is a different modification of the right hand end of the machine shown in Fig. 1.

Fig. 4 shows the spindle head with chuck and feeding sleeve.

Fig. 5 and Fig. 6 are an end view, and a longi-' tudinal section along BB, respectively of a clutch arranged between the bar guides and the spindle drum, in an engaged position.

Fig. 7 is an end view of the same parts when disengaged. I

Fig. 8 is a detail of the clutch.

Fig; 9 and Fig. 10 are a longitudinal section and a side view of the signalling device.

Figs. 11 to 15 show details of the signalling device.

Fig. 16 shows the end portion of the machine provided with an automatic mechanism for controlling the feeding of the bars.

Fig. 17 shows an accessory to the controlling mechanism on a larger scale.

-The bed i (Fig. 1) carries the headstock 2 with the indexing spindle drum 3. Within the latter the rotating spindles 4 for the material are situated. To the left of the machine the bar guiding device 5 is arranged, which rests on the support 6 and on the left hand end of the lathe. This device 5 mainly consists of the discs 1 and 9, which are rigidly connected with each other by the bars 9. The guide tubes 19 for the bar material ii are rigidly secured in apertures provided in the discs 1 and 3. The .bar guiding arrangement 3 can be disengaged from and re-arranged with the spindle drum 3 while the latter is working. A bar I2 is arranged on and connected with the spindle drum 3, and the engaging disc l3 Thedisc 13 (Fig. 6) is provided with holes 14 into which engaging pins I6 slidably mounted in disc 3 may penetrate.

The engagement and disengagement of the clutch is eifected in the following manner: A control disc i9 is rotated by means of a hand wheel l9 provided with an internal gear, and by means of pinions l1 and 19. This disc I9 is provided with inclined slots 20 (Fig. 8), and the screw bolts 2| (Fig. 6) of the engaging pins (5 engaged in these slots move the pins on rotating the hand wheel l6, whereby the bar guiding device I (Fig. 1) is engaged with or disengaged from the spindle drum 3. In the engaged position (Figs. 5 and 6) the apertures 22 in the control disc l9 register with the guide tubes l9. The' According to a, further development of my invention a signalling device 23, comprising for instance a source of green light 24, is operated, and the bar guiding device is disconnected from the spindle drum, as soon as the longest bar has cleared the bar guiding device. This result may be achieved by means of the following mechanism: A projecting stop 25 is rigidly secured to the engaging disc l3 indexing together with the spindle drum 3 (Figs. 2, .5, and 6). After each complete revolution of the spindle drum in the direction of the arrow a limited rotary movement is imparted to a ring 23 by means of a bellcrank lever 26 (Fig. 2) and a connecting rod 21.

Furthermore, a limited rotary movement in the opposite direction is imparted to a ring 31 by the bar II by means of a bellcrank lever 29 and a connecting rod 39. The latter action takes place after each indexing movement of the spindle drum '3 so long as the ends of the bars II are still in touch with the bellcrank lever 29, i. e. so long as they have not cleared the bar guiding device I. The ring 29 (Fig. 11) is turned to the right against the pressure of a spring 32, causing a pawl 33 to proceed by one tooth. On release by means of the projecting stop 25 (Fig. 2), spring 32 (Fig. 11) turns the ring 29 back into the starting position, whereby the ratchet wheel 34 is turned to the left. The ring 3i (Fig. 2) is turned to the left against the pressure of a spring 39 (Fig. 12) whereby a pawl 36 is caused to proceed by one tooth. When the indexing bar ll releases the bellcrank lever 29 (Fig. 2) the spring 35 (Fig. 12) turns the ring 3| back into the starting position, whereby the ratchet wheel 31 is turned to the right. The starting position of the ring 29 is defined by a stop 39 (Fig. 11), and

The portion 49 of the signals by means of a further device 46 described below. The ratchet wheel 31 is turned to the right against friction by each indexing step so long as any bars II are left in the bar guiding device 5, and it also turns the bevel gear wheel 42 by means of bevel gear wheel 4|. So long as the cam disc 44 connected with the bevel gear wheel 42 is prevented from turning to the right by the projection 41 (Fig. 13) of the cam disc 45 to which it is adJustably connected, and by the projection or lug 48 on the lever 49, the ratchet wheel 34 is turned to the left against friction. This ratchet wheel 34 (Figs. 11 and 9) which is turned to the left by each complete revolution of the spindle drum, turns the bevel gear wheel 42 by means of the bevel gear wheel 49. The bevel gear wheel 4| is prevented from rotating by a frictional disc 50 urged by a spring. This means that the bevel gear wheel 42 revolves as a planetary gear which also rotates to the left the cam discs 44 and45.

The bellcrank levers 26 and 29 co-operate in the following manner: On each complete revolution of the spindle drum the bellcrank lever 26 (Fig. 2) causes the ratchet wheel 34 (Figs. 11 and 9) to proceed by one tooth. The

cam discs

44 and 45 are slightly turned thereby, but they are turned back by one tooth at the next indexing step by means of the bellcrank lever 29 (Fig. 2) and the ratchet wheel 31 (Figs. 12 and 9). So long as one bar still remains in the bar guiding device 5 the

cam discs

44 and 45 will, consequently, move merely slightly forward and backward. Any further rotation by the plurality of bars is prevented by the projection 48 of the lever 49 (Fig. 13) as has been explained above. When the last bar I I (Fig. 2) has cleared the bar guiding device, the bellcrank lever 29 is no longer actuated by the indexing steps, and the ratchet wheel 34 (Figs. 11 and 9) proceeds to the left by one tooth on each complete revolution of the spindle drum. As soon as the cam disc 45 (Fig. 13) has slightly turned to the left the bevel face of the projection 41 turns the bellcrank lever 5| to the left about the bolt 52 against the pressure of the spring 55. The projection 53 of the lever 49 is thereby released. A spring 54 turns the lever 49 downwardly about the pivot I6. The lever 49 is provided with a stud 56 (Figs. 13 and 15) making electrical contact between the two

contact elements

51 and 58. The green lamp 24 (Fig. 1) is thereby switched on, indicating that the operator may now disconnect the bar guiding device 5 from the spindle drum 3, and that fresh bars may be inserted in the bar guides while the lathe continues to operate. On further rotation of the cam discs 44 and 45 (Fig. 13) the projection 59 of the cam disc 44 strikes, after a certain period, the crank lever 60 (Fig. 14), which, engaging the fixed stud 52 by a slot 15, moves somewhat to the right, whereupon its nose slips off the fixed stop 6|. A spring 62 draws the lever 60 downward. The lever 60 is also provided with a stud 63 (Fig. 14 and Fig. 15) which makes contact between the two

contact pieces

64 and 65. The red lamp 66 (Fig. 1) is thereby switched on, indicating that the bars II are used up except for a residual portion 61 (Fig. 4) remaining in the chuck 68, and that the lathe can be stopped in order to feed the fresh bar material forward into the chucks.

The time lag between the switching on of the red and the green lamp is adjusted by turning the

cam discs

44 and 45 relatively to each other, and locking them in adjusted position. This is done by releasing a nut 69, adjusting a zero disc 16 (Figs. 1 and 10) with respect to a graduated disc H and tightening the nut 69 again. The zero disc 10 is connected to the cam disc 44, and the graduated disc II is connected to the cam disc 45. The adjustment of these two discs 10 and II depends on the length of material required for one blank or piece of work, or on the requisite number of indexing steps of the spindle drum with reference to the constant length of the bar material between the bar guiding device and the chucks. The graduation on disc 1| is in terms of the length of material required for one piece of work. This is in accordance with the fact that the bars are fed forward by each complete revolution of the drum by the length required for one piece of work, which is in a definite relation to the constant length of the end portion, as mentioned above.

After feeding the bars into the chucks as explained the operator turns the zero disc 10 (Figs. 9'and 10) by its knob until a zero mark on the graduated disc ll coincides with a zero mark 12 on the fixed casing 13, whereby the green and the red lamps are switched off simultaneously. Should the attendant forget to switch ofi the lamps, the return into the zero position is effected automatically, as the bellcrank lever 29 (Fig. 2) is moved'by the bars II in a similar way as described above in connection with the signalling device 23. After the return into the starting position the lamps are switched off in the following manner: As explained above, the cam discs 44 and 45 (Figs. 13 and 9) are secured to each other as well as to the zero disc Ill and the graduated disc ll (Fig. 9). On turning the graduated disc II to the right, the cam discs 44 and 45 (Fig. 13) are also turned to the right, whereby the projection 41 of the cam disc 45 bears against the nose 48 of the lever 49, lifting this lever as well as the stud 56 from the two contact pieces 51 and 58 (Figs. 15 and 13). The lever 49 comes to rest against the pivot 52. The green lamp is thus switched off. The lever 49 is arrested in this starting position bya bellcrank l-ever 5|, one arm of which is forced beneath a projection 53 of the lever 49 by means of a spring 55. Simultaneously a small pin 14 (Fig. 13) laterally projecting from lever 49 lifts the lever 60 (Fig. 14), thus also lifting the stud 63 (Figs. 14 and 15) of the lever 60 from the two

contact elements

64 and 65. The red lamp is thereby switched off. The lever 60 is arrested in this starting position by its nose abutting against the fixed stop 6|, whereby the lever 60 is forced to the left by spring 62, sliding on the fixed pivot 52.

Instead of the planetary gear as described I may employ any other mechanism counting the revolutions of the drum and, after a predetermined number of revolutions operating a signal or an actuating device. In any'case it is essential that feelers are employed against which the bars move during the indexing, as the occurrence of grooves or marks at the points of contact of the bars and the feeler are thereby prevented. It is furthermore essential that a mechanism is employed to which positive as well as negative impulses are imparted, so that the impulses occurring during a complete revolution of the spindle drum cancel out or compensate each other so long as any bar material remains within the reach of the feelers. With this provision a single feeler getting into touch with the bars ll enables me to ascertain mechanically the moment at which the longest bar II has just cleared the controlled space.

In case the cam shaft of the whole mechanism is desired to be stopped not by hand but automatically as soon as the red lamp is switched on, I may resort to the following arrangement: A magnet 11 (Fig. 1) is inserted in the circuit of the red lamp and, when excited, actuates the bellcrank lever I8. A bar 19 is thereby forced to the left against the pressure of a spring and in turn forces the crank lever 88 into the path of the cam 8| secured to the cam shaft 82. As soon as the cam 8| turns the crank lever 88 the bar 19 is also turned. This bar 19 also carries a second lever 83 which participates in the revolution, thus disengaging a clutch 84 and arresting the cam shaft 82. The lever 83 turns in two bearings on the spot, the bar 19 sliding through it. Instead of the lever 83 another lever 85 (Fig. 3) could be used to actuate for instance a press-button switch so as to disconnect the main driving motor 81 (Fig. 1) or to throw out a frictional clutch in the main transmission train. As the arresting is effected automatically by the cam shaft 82 it takes place (provided that the cam 8| is arranged properly) at the exact moment when the tools and the stop for the material (not shown) have been withdrawn, as their movements are also controlled by the cam shaft 82.

After this the first bar II may be moved forward into the chuck 88 (Fig. 4), thereby ejecting the residual bar portion 81, which drops freely. The advance of the bar material is effected in the following manner: As described above, the attendant has placed the bars I I in the bar guiding device 5 after the green lamp had been switched on. 'He now connects the bar guiding device 5 with the spindle drum3 by turning the hand wheel I6 (Fig. 1). Simultaneously therewith the controlling disc I 9 (Fig. 6) uncovers or releases the guide tubes I8. In order to feed forward the first bar the cam roller 94 (Fig. 1) is first withdrawn and the bar is then drawn as far as the feeding sleeve 9| (Fig. 4) by means of the handle 88 (Figs. 1 and 2), the rod 89 and the engaging arm 98. The bar 92 (Fig. 1) serves as a guide. The weight 93 subsequently returns this traction device into its starting position. By actuating the hand lever 95 the feeding sleeve 9| (Fig. 4) is now slipped over the bar II, whereupon the latter is moved through the open chuck 88 into the working position by means of the hand lever mentioned. The attendant now allows the machine to run until it is arrested, by the cam 8| (Fig. 1), as described above, at the next indexing step. The next fresh bar is now moved forward, and so on. After all the bars have been moved forward the attendant has to bring the cam roller 94 back into the path of the cam. After that the signalling device 23 must be restored to its original position, whereby the lamps are switched off and the magnet I1 is caused to release the bellcrank lever I8. The crank lever 88 due to the action of the spring, is thereby withdrawn from the'path of the cam 8|. The cam shaft 82 is re-engaged, or the main driving motor 'I8 is restarted, and the machine now works regularly again.

According to the above described embodiment of my present invention the sequence of steps in the operation of the machine, intended to reduce the loss of time, is as follows: I

When the green lamp 24 is switched on au tomatically the hand wheel I8 is turned so as to disconnect the bar guiding device I from the spindle drum 8. While the lathe continues running fresh bars II of the stock are placed in the bar guiding device 5. Somewhat later the red light is switched on automatically, indicating that the end portions of the bars in the lathe have been used up. Either the attendant stops the machine by hand, or it is automatically arrested, as described, by the cam shaft 82 being disengaged or the main driving train being interrupted. If the machine is stopped by hand, the cam shaft 82 must be turned in the well known manner by means of a hand wheel (not shown) until the tools and the stop for the material are withdrawn. After this the cam roller 94 is withdrawn, and the bars are moved into the working position one after the other by means of the handle 88 and the hand lever 95. The signalling device 23 is set to zero. In the case of an au tomatical arrest of the lathe the lever 88 is simultaneously moved out of the path oi. the cam as described. After this the cam roller 94 is returned into the path of the cam, and the machine is started by hand.

If the bar guiding device 5 (Fig. 1) is to be disconnected not by hand, but automatically, the following device (Fig. 7) is provided. As described above, a green lamp (Fig. 1) is switched on as soon as the longest bar II has cleared the bar guiding device 5. The circuit employed for this purpose also excites a magnet 98 (Fig. 7). whereby two

levers

91 and 98 connected with each other and having a common pivot 89 are turned against the action of springs I88 and MI so that a lug I82 on the lever 91 engages in a recess or notch provided in the hand wheel I6. The hand wheel is locked thereby, and at the next indexing step the bar guiding device (Fig. 1) is disconnected from the spindle drum 3.

Before feeding the bars II forward into the spindle drum 3 the bar guiding device and the spindle drum 3 have to be re-coupled, this being effected by hand as described. As the circuit exciting the magnet 98 (Fig. '7) rema'ns closed there is, however, another facility wante to withdraw the lug I82 on the lever 91 from the hand wheel I6. This is accomplished by means of the hand lever I83, which is turned to the right against the pressure of a spring I84. A lug I85 of the hand lever I83 is thereby caused to slip off the lug I86 of the lever 98, whereupon the spring I88 turns the lever 91 as far as the stop I81 so as to withdraw the lug I82 from the hand wheel I8. Later on, when the magnet 98 is no longer excited, the spring I8| pulls the lever 98 downward, and owing to the pressure of the spring I84 the lugs I85 and I88 are again superimposed. The position of the levers will then be the same as shown, but the whole system will be slightly turned to the right owing to the withdrawal of the lug I82.

After the green light 24 (Fig. 1) has been switched on the bar guiding device 5 (Figs. 1 and 16) is arrested automatically as described. Fresh bars II are now inserted in the bar guides by hand, and a feeding dog I88 (for feeding the bar automatically later on) is temporarily turned aside against the action of 'a spring when inserting the lowest bar. Thereupon the bar guiding device and the spindle drum are coupled as described by turning the handle I8. As soon as the end portion of the bars remaining in the spindle drum are used up, the red light 58 (Fig. 1) is switched on as described and the magnet I89 (Fig. 17) is excited, causingthe interconnected levers H8 and III to be turned about their comon pivot I I2. The shaft I I3 is forced to the left gainst the pressure of a spring and the crank ver H4 is forced into the path of the cam H8 arranged on the cam shaft 82. As soon as the cam I I5 moves the crank lever H4, the shaft H3 is turned against the action of a spring. This shaft I I3 carries another lever I I6, which is also turned and actuates the electrical switch H1 so as to arrest the main driving motor 81. The lever H6 turns in two hearings on the spot, the shaft I I3 being moved through it. As the arrest as described is effected automatically by the cam shaft 82, it takes place (provided that the cam H6 is arranged properly) in the exact moment when the tools and the material stop (notshown) have been withdrawn, as their movements are all controlled by the cam shaft 82.

The electrical switch H1 not only switches off the main driving motor 81 but it also switches on simultaneously the auxiliary motor H8 (Fig. 16) which turns the cam drum H8 reciprocating a slide I20. In Fig. 16the starting or resting position of the feeding mechanism proper is shown. On rotating the cam drum H8 the slide I20 first moves slightly to the left. Thereby the thin connecting rod I2I is also moved to the left, and through the-interaction of a segmentary gear lever I22 a bevel pinion I23 and a shaft I24 are turned against the action of a torsional spring. The bevel gear wheel I23 forms a bearing for the shaft I24 which is axially displaceable and participates in the revolution of the bevel gear by means of a tongue and groove connection. An abutment or stop arm I25 and an arresting arm I26 are rigidly secured to the shaft I24. The abutment arm I25 (Fig. 5) is rocked from the position shown in full lines into the position shown in chain-dotted lines in front of the bar which is to be advanced. As soon as this position is assumed the arresting lever I26 (Fig. 16) slides from the end face of the stop I21, whereupon the shaft I24, together with the arm I26, is slightly moved to the left. The arm I26 comes to rest against the side face of the stop I21, thus holding the abutment arm I25 in the chain-dotted position (Fig. 5). On further rotation of the cam drum H8 the slide I20 moves to the right. This slide I20 is connected by a pawl I28 to the slide I28, which, is loosely arranged on a bar I32 and actuates the feeding slide I3I and its feeding dog I08 mentioned above by means of a thin connecting rod. In this travelling to the right the bar II is fed forward by the feeding dog I06. Simultaneously therewith the bar I32, which has a shoulder I33 bearing against the slide I29, follows said movement of the slide I28 to the right by means of a retracting spring I34 urging said shoulder I33 against the slide I28. As soon as the right hand end of the bar II encounters the abutment arm I25, the bar II moves the arm I25 and the shaft I24, which are connected together, somewhat to the right against the action of a pressure spring. This slight movement of the shaft I24 to the right causes the arresting arm I26 secured to the shaft I24 to slide from the side face of the stop I21. Thereupon the shaft I24 is rotated by the action of the torsional spring previously put under tension and the arm I26 is urged by said torsional spring against a saw toothing at the end of the bar I32, whereby further motion of said bar I 32 to the right is arrested, so that the slide I28 moves freely on the bar I32. At the same time the abutment arm I25 is rocked into the position shown in full lines in Fig. 5, so that it comes out by means of a stop I38 adiustably secured to the bar I32. As soon as the advancing pawl I28 pivoted on the slide I28 strikes against the sloping face of the stop I38, the slide I28 is disengaged from the slide I20. The distance between the pawl I28 and the stop I38 corresponds to the desired advance of the bars I I counted from the point of contact with the abutment arm I26. After having been disengaged the slide I20 travels further to the right and then back to the left, according to the shape of the cam drum H8. Thereafter the slide I20 strikes against a proiection I31 of the slide I28, leading the latter back into the starting position as shown. During this movement the arresting arm I28 slides over the sloping faces of the saw toothing I36. As soon as this starting position is attained, i. e. after one revolution of the cam drum, a cam I38 actuates an electrical switch I38 disconnecting the auxiliary motor H8 and simultaneously switching on the main driving motor 81 (Fig. 17). The lathe now runs for one period of work (between two indexing movements) Thereafter the main driving motor 81 is switched off again, the auxiliary motor H8 is switched on, and this cycle is repeated a number of times corresponding to the number of spindles.

After the last bar II has been introduced it is necessary that the lathe, when being restarted, resumes its regular running without interruptions. This is attained by the following arrangement: On the shaft I40 carrying the cam drum H8, a control disc I is loosely mounted, and the train of gear wheels I42 causes this control disc I to complete one revolution while the cam drum H8 completes as many revolutions as there are spindles. During the last partial revolution of the control disc HI, 1. e. during the last revolution of the cam drum H8, a cam I43 (Fig. 16) actuates an electrical switch I44. The magnet I46 (Fig. 17) is excited thereby for a short period and pulls downward, against the action of a spring, the right hand end of a lever I46 which is pivotaliy mounted on the end of a lever III. By this movement the left hand end of the lever I46 unlocks the two levers H0 and III, whereupon the bar H3 and the crank lever H4 are moved to the right by spring action. The crank lever H4 is thereby withdrawn from the path of the cam H6. This means that after the electrical switch I38 (Fig. 16) has been actuated for the last time the lathe resumes its regular operation as the cam H5 does no longer strike the crank lever H4. Subsequently, when the magnet I08 is no longer excited, i. e. when the signalling device 23 (Fig. 1) has been returned automatically into its starting position and the red light is switched off, the lever H0 (Fig. 17) is turned by spring action in counter-clockwise direction until its lug I41 bears against the lever II I. The lever I46 then again locks the two levers I I0 and III.

With this semi-automatic arrangement the attendant has merely to introduce the fresh bar device and to throw in again the clutch between the bar guiding device and the spindle druni.

I claim:

1. A multi-spindle turret lathe for bar material comprising a spindle drum, a bar guiding device arranged to participate in the regular indexing motions of said spindle drum, and a clutch inserted between said drum and said bar guiding device so as to allow the latter to be arrested and recharged during the operation oi! the lathe. 2. A multi-spindle turret lathe for bar material comprising a spindle drum, a bar guiding device arranged to participate in the regular indexing motions of said spindle drum, a clutch inserted between said drum and said bar guiding device so as to allow the latter to be arrested and recharged during the operation of the lathe, a controlling mechanism arranged to be actuated by the longest bar contained in said spindles when leaving the barguiding device, and a signailing device operativelyconnected with said controlling device so as to indicate the moment when said bar guiding device should be arrested.

3. A multi-spindle turret lathe for bar material comprising a spindle drum, a bar guiding device arranged'to participate in the regular indexing motions of said spindle drum, a clutch inserted between said drum and said bar guiding device so as to allow the latter to be arrested and recharged during the operation of the lathe, a controlling mechanism arranged to be actuated by the longest bar contained in said spindles when leaving the bar guiding device, and a transmitting device arranged to throw out said clutch automatically on receiving an impulse from said controlling device.

4. A multi-spindle turret lathe for bar material comprising a spindle drum, a bar guiding device arranged to participate in the regular indexing motions of said spindle drum, a clutch inserted between said drum and said bar guiding device so as to allow the latter to be arrested and recharged during the operation of the lathe, a controlling mechanism arranged to be actuated by the longest bar contained in said spindles when leaving the bar guiding device, a transmitting device arranged to throw out said clutch automatically on receiving an impulse from said controlling device, and a signalling device operatively connected with said controlling device so as to indicate the accomplished arrest of said bar guiding device.

5. A multi-spindle turret lathe for bar material comprising a spindle drum, a bar guiding device arranged to participate in the regular indexing motions of said spindle drum, a clutch inserted between said drum and said bar guiding device so as to allow the latter to be arrested and recharged during the operation of the lathe, a controlling mechanism arranged to be actuated by the longest bar contained in said spindles when leaving the bar guiding device, a signalling device operatively connected with said controlling device so as to indicate the moment when said bar guiding device should be arrested, a delayed action mechanism arranged to be released by the impulse due to said controlling device and torelease a second impulse after a predetermined number of further indexing steps of said spindle drum, said mechanismbeing adjustable in terms of such indexing steps, and a second signalling device operatively connected with said delayed action mechanism so as to indicate when the lath should be arrested and recharged.

6. A multi-spindle turret lathe for bar material comprising a spindle drum, a bar guiding device arranged to participate in the regular indexing motions of said spindle drum, a clutch inserted between. said drum and said bar guiding device so as to allow the latter. to be arrested and recharged during the operation 01' the lathe, a controlling mechanism arranged to be actuated by the longest bar contained'in said spindles when leaving the bar guiding device, a signalling device operatively connected with said controlling device so as'to indicate the moment when said bar guiding device should be arrested, a delayed action mechanism arranged to be released by the impulse due to said controlling device and to release a second impulse after a predetermined number of further indexing steps of said spindle drum, said delayed action mechanism being ad- Justable in terms of such indexing steps, and a switch operatively connected with said delayed action mechanism and arranged to arrest the lathe on receiving such second impulse.

7. A multi-spindle turret lathe for bar material comprising a spindle drum, a bar guiding device arranged to participate in the regular indexing motions of said spindle drum, a clutch inserted between said drum and said bar guiding device so as to allow the latter to be arrested and recharged during the operation of the lathe, and

a controlling mechanism producing a controlling impulse, said controlling mechanism receiving an auxiliary impulse in one sense by each revolution of said spindle drum and further auxiliary impulses in an opposite sense by the indexing motions of such bar material as is still partly positioned in said bar guiding device, the controlling impulse being released only after an auxiliary impulse in the first sense has not been cancelled out by at least one auxilary impulse in the opposite sense during one revolution of said spindle drum.

8. A multi-spindle turret lathe forbar material comprising a spindle drum, a bar guiding device arranged to participate in the regular indexing motions of said spindle drum, a clutch inserted between said drmn and said bar guiding device so as to allow the latter, when empty, to be arrested and recharged during the operation of the lathe, a controlling mechanism arranged to receive an auxiliary impulse in one sense by each revolution of said spindle drum, and a i'eeler in the path of the indexing motion of such bar material as is said feeler being arranged to impart auxiliary impulses to said controlling mechanism each time the ieeler is struck by a bar, while a controlling impulse is released by said controlling mechanism only after an auxiliary impulse due to said spindle drum has not been cancelled out by at least one auxiliary impulse due to said feeler during one revolution oi said spindle drum.

9. A multi-spindle turret lathe for bar material comprising a spindle drum, a bar guiding device arranged to participate in the regular indexing motions of said spindle drum, a clutch inserted between said drum and said bar guiding device so as to allow the latter to be arrested and recharged during the operation oi. the lathe, a controlling mechanism arranged to be actuated by the longest bar contained in said spindles when leaving the bar guiding device, a signalling device operatively connected with said controlling device so as to indicate the moment when said bar guiding device should be arrested, a delayed action mechanism arranged to be released by the impulse due to said controlling device and to release a still partly positioned in said bar guiding device,

second impulse after a predetermined number of further indexing steps of said spindle drum, said delayed action mechanism being adjustable in terms or such indexing steps, a main switch operatively connected with said delayed action mechanism and arranged to arrest the lathe on receiving such second impulse, and an auxiliary cam drum arranged and designed to control automatically the steps involved in advancing the individual bars into said spindles in the course oi recharging the lathe, said auxiliary cam drum being switched in automatically as soon as the main switch arrests the lathe.

10. A multi-spindle turret lathe for bar material comprising a spindle drum, a bar guiding device arranged to participate in the regular indexing motions of said spindle drum, a clutch inserted between said drum and said bar guiding device so as to allow the latter to be arrested and recharged during the operation of the lathe, a controlling mechanism arranged to be actuated by the longest bar contained in said spindles when leaving the bar guiding device, a signalling device operatively connected with said controlling device so as to indicate the moment when said bar guiding device should be arrested, a delayed action mechanism arranged to be released by the impulse due to said controlling device and to release a second impulse after a predetermined number of further indexing steps of said spindle drum, said delayed action mechanism being adjustable in terms oi such indexing steps, a main switch operatively connected with said delayed action mechanism and arranged to arrest the lathe on receiving such second impulse, an auxiliary cam drum arranged and designed to control automatically the steps involved in advancing the individual bars into said spindles in the course of recharging the lathe, said auxiliary cam drum being switched in automatically as'soon as the main switch arrests the lathe, and a counting device counting the revolutions of said auxiliary cam drum and arresting the latter and switching in the main drive of the lathe as soon as the auxiliary cam drum has performed a number of revolutions corresponding to that of the spindles.

FRITZ POPPENSIEKER.