GB2092046A - Multi-spindle lathe drive - Google Patents

Abstract

A multi spindle lathe including a number of workspindles 5 carried by an indexable spindle Drum 4 housed in a Drum Headstock 1 has a Quill Housing 2 longitudinally spaced from the Drum Headstock 1 carrying End working Quills 6. These are operated directly by Levers in contact with cams 7 carried by camshafts 17. Drive to the workspindles 5 is arranged from a free running idler gear 13 mounted on a stationary sleeve lying within a bore of the Quill Housing 2, this bore being in alignment with one of the workspindles when the indexing Drum 4 is locked in a working position. The free running idler gear 13 driven by a train of gears 15 itself drives a gear 12 central with respect to the pitch circle of the Quills 6 and the workspindles 5. The gear 12 has an extended shaft 9 carrying a central gear 10 which in turn drives the gears 11 mounted on the workspindles 5. A worm 26 drives a camshaft 28 for tool slides and clutches 34 are used for drive coupling and braking. <IMAGE>

Description

SPECIFICATION A multi spindle lathe The Multi Spindle Lathe, the subject of this application consists basically of a Spindle Drum Headstock 1, (see Fig. 1), an end working Quill Housing 2 both assemblies 1 8 2 being mounted on a Base 3, together with Stock Tubes 40 for carrying Bar material.

The Drum Headstock is bored to receive a Spindle Drum 4 having a number of jour nalled Work Spindles 5, equally spaced around a Pitch Circle whose radius lies within the outside diameter of the Drum, the Drum being mounted horizontally. The Quill Housing 2 spatially opposed longitudinally from the Spindle Drum Headstock 01carries a number of Tool carrying Quills 6, equal in number to the number of Workspindles 5, each Quill 6 being arranged in horizontal alignment with a workspindle such that when the workspindles 5 are rotated, cams 7 giving reciprocal movement to the Tool Quills towards the Work Spindles 5, cause such Tools as Drills, Turning Tools, carried by the Quills 6 to have a cutting action on Bar or other material clamped within the Workspindles 5.

The circular Drum 4 is provided with mechanism for indexing & locating, so that each Workspindle 5, is presented in turn to each of the Tool Quills 6, for the appropriate cutting action to take place in sequence. The drive to the workspindles 5 is arranged from a shaft 9, central in relation to the Spindle Pitch Circle, carrying a Gear 10 which meshes with & drives gears 11 fitted in alignment on each of the workspindles 5, in turn the centre shaft 9 is driven by a gear 12 mounted at the opposite end of the shaft 9 positioned within the Quill Housing 2, this latter gear 12 being driven by a gear 1 3, mounted on a stationery sleeve surrounding one of the Tool Quills 6.

This (Fig. 4) method of mounting S accomodating the stationery sleeve gear 13 is novel, and results in the practical possibility of a machine having vertical camshafts together with Quill Operating mechanisms, simple and accessible lengthwise Quill adjustments, as described later without the necessity of incorporating a very long & unstable centre driving shaft together with a separate housing for accomodating the associated driving gears as would be required in the event that the stationery sleeve gear 13 was not applied.The stationery sleeve gear 13 makes it possible with this construction, to provide a short central drive shaft 9 for driving the Workspindles 5 so that 2 vertical camshafts 17 one on each side of the Quill Housing 2 (see Fig. 2) and associated levers as shewn at 18 can be actuated by cams 16, and the lengthwise adjusting units 20 are all readily accessible to an operator. The long central shaft and associated gear housing required were the stationery sleeve gear 13 not available would render the construction as described impossible.The stationery sleeve gear 13 is driven by a train of gears 15 positioned in the Quill Housing 2 substantially below the Quill Sleeve gear 13, the the gear train comprising at least two accessable change gears so that the speed of Lhs workspindles 5 can be changed to suit the cutting characteristics of the different materials s different diameters of worksubjects.The end Working Quills 6 are operated towards the Workspindles 5 by cams 16 (Fig. 2) the cams being carried by vertical detachable camshafts 17 at right angles to the longitudinal centre line of Quills 6, which latter are operated by levers 1 8 having rollers in contact with the cam surfaces at one end, the the levers being pivotted between the rollers at 19 s & n endwise adjusting unit 20 at the opposite end, the adjustment unit being swivellably connected to the Quills 6 by pins 21.

The endwise adjusting units 20 are bolted to a surface of the levers 18 such that they can be positioned at various lengthwise distances from the lever pivots so providing a limited amount of variable stroke. The cams are arranged to give positive end working pressure in a direction towards the workspindles 5 for feeding drills and other end working tools into the the work material, while the return motion is by spring pressure but with the safeguard that a secondary projection 22 on each lever substantially opposite to the roller carrying portion of the lever 18 provides a positive return to each lever and consequently to each quill 6. The two vertical camshafts 17 as described are connected together in timed relationship by gears 23 meshing together preferably positioned under the Quill Housing 2.One of the vertical camshafts is driven by a "master" worm elm wheel 24 keyed to the camshaft 1 7. The master worm 24 is connected in 1:1 relation by longitudinal shaft 25 8 appropriate gears to a secondary worm 26 driving a worm wheel 27 of like ratio to the first worm ti wheel 24. This worm wheel 27 and detachable camshaft 28 carrying on its Right hand side a series of Disc cams 8 levers (not shown) having limited stroke adjustment similar to levers 18 already described.These levers together with appropriate linking mechanisms operate cross slides suitably arranged relative to the worlcspindles 5 and used for mounting form tools, knurls, necking and other tools and in one particular station for Cutting Off Tool for severing finished workpieces from bar material carried in the workspindles. Cam shaft 28 also carries a Geneva Roll 29 intermittently engaging slots in a Geneva Disc integral with which is a gear for indexing the Spindle Drum 4 from one station to another.This camshaft 28 carries a cam drum 30 a operates, Spindle Drum locking s unlocking, mechanism for collet opening s closing, Bar feeding mechanism and where required other auxiliary mechanisms. The Drum Housing 1, the Quill Housing 2 8 the mechanisms as described are all mounted on a Base 3 which accomodates a large quantity of cutting fluid (coolant) Coolant Pump, filters, baffles, Lubricating tank 8 Pump, a swarf (cuttings) conveyor and carries the Electric Motor for driving the complete machine. Drive to the "master" worm 24 is derived from a gear 33 which is not changeable s which is positioned in the workspindle drive train 15.

This gear 33 maintains a constant relationship with the spindle drive gears such that the endwise tool advance remains constant per revolution even if the spindle speed is changed. The change gear train driving the worm 24 provides means of changing the tool advance per revolution of the workspindle and in consequence the cycle time. With the mechanisms as described 180 approximately of camshaft rotation is used for cutting operations 8 approximately 1 80' in fast motions for auxiliary motions eg Tool return stroke, Drum indexing, Bar feed etc. These auxiliary motions motions are carried out at the maximum speed possible in order to keep the total cycle time as short as possible.The drive to the "master" worm s wheel 24 for these fast operations is derived from a constant speed shaft (not shewn) which is at the appropriate speed from the driving motor. A shaft in the Quill Housing 2 carries three friction clutches 34, one is driven from the non changeable gear in the workspindle gear train, the workspindle drive change gears being subsequent to the non changeable gear, the second clutch is driven from the constant speed shaft already mentioned and drives the "master" worm 24 at a constant fast motion speed during 1 80' of camshaft rotation. The first clutch drives through a train gear to the clutch, Et controls the tool advance per revolution s hence the cycle time.The third clutch acts as brake & is applied at the end of the fast motion cycle 1 80', to absorb the kinetic energy generated by the high speed. Each of these clutches is engaged s disengaged at the period during the machine cycle by trip dogs carried on one of the camshafts 17 or 28. A freewheel may be provided to carry the drive over a possible "dead" period between cutting cycle and fast motion. The complete cycle---cutting auxiliary motions may be run at the fast auxiliary motion rate where very short simple workpieces are being produce. In this condition the fast auxiliary clutch only is constantly engaged, the other 2 clutches being left disengaged.The complete cycle is thus run through 360" of camshaft rotation and where a small capacity automatic lathe to which this descriptive matter is particularly applicable e.g. a 1 4m/m capacity machine, this 360 may be run in a cycle time of 0,8 seconds, or even slightly faster, 0,4 seconds for cutting operations 8 0,4 seconds for the auxiliary motions. Under these conditions there is no wear on any of the clutches.

Where there are insufficient spindle revolutions in 0,4 seconds and for example 0,5 seconds would provide sufficient cutting revolutions there would be very high wear on all the clutches because of the high frequency of changing from cutting cycle to fast motions s back continually. Here it is preferable to provide a changeable gear in the fast motion train of gears giving 0,5 seconds in cutting cycle s 0,5 seconds for auxiliary motions.

Electro magnetic clutches may be applied instead of the nechanical friction clutches but here again the foregoing conditions apply.

In order to make it possible to achieve an auxiliary motion time of 0,4 seconds or even slightly less it is essential that all separate motions are overlapped, i,e. more than one motion takes place simultaneously. For example Fast Tool Return is overlapped with retraction of the Bar feed finger ready to feed the next length of Bar; collet opening is also carried out during Fast Tool Return; collet opening is also carried out during Fast Tool Return; the spindle drum is unlocked ready for indexing; during indexing new bar is fed forwards to a stop dog for producing the next workpiece s the gripping collet is closed.

After this indexing motion is completed 8 the spindle drum is locked, fast motion ends 8 tool cutting cycle commences. Only by overlapping various motions as described can such a fast idle time of 0,4 seconds be achieved.

Rotating Attachments are required in place of the normally non-rotating Quills 6 for such operations as high speed drilling (contra rotation relative to the workspindle direction of rotation), Thread cutting by means of Self Opening Dieheads, Synchronous Pick up Attachment, Tapping Attachment etc. These attachments in the present proposal are driven by a cluster gear 35 carried by centre shaft 9 s positioned on the rear of the Quill Housing 2. The attachments are constructed as one piece units so that they can be mounted in any particular station or changed from one station to another after removal of the non rotating Quill, the units themselves not needing any dismantling. This change over of Rotating Attachments can be carried out extremely quickly whenever changing tool set up for a new workpiece, the gears for driving the Rotary Attachments meshing with the cluster gear 35. The Unit for tapping requires a change of speed, the tap spindle underrunning the work spindle for tapping a RIGHT HAND thread s over-running the workspindle for a withdrawal of the tap. This Attachment is driven from a Gearbox 36 situated on the top of Housing 2 8 this gearbox has a layshaft with differing gears which drive, in turn, the Tapping Spindle at the under 8 overrunning speeds through a train of gears fitted to the rear face of the Quill Housing 2 but positioned outside of the gears for driving the other attachments. The layshaft is driven at one speed only by the normal Rotary Attachment gears.Operations such as cross drilling of workpieces or milling of flats on workpieces, before cutting off, from the cross slides of the machine require that the workspindle 5 in a particular station is stopped.

For this purpose each workspindle is provided with a clutch 37 8 brake 38 which may be operated by a stationery cam on the outside of the spinle drum 4 during indexing or by trips on the camshaft 28. The cross slide, such as 29, on which the cross drilling is to be mounted is designed so tha its motion is parallel to a line joining the workspindle centre s the centre of the Spindle Drum 4.

Additional cams carried by or driven from camshaft 28 may be arranged to operate a Pick Up Arm or Disc for transferring cut off workpieces into alignment with a saw carried by an Attachment fitted to a facing on the fromt of the Drum Housing 1 for slotting screws or flat milling on workpieces. Alternatively a CROSS Drilling Attachment may be applied in the place of the Sawing Attachment. Still further a Bent tap type Tapping Attachment may be applied in place of the other Attachments.

The machine as described is capable of producing simple workpieces in 0,8 seconds i.e. 75 pieces per minute, alternatively at 2 pieces per cycle 150 pieces per minute. Under these conditions 8 even where longer cycles are involved a full load of bar material may be used in approximately 10 minutes.

Because of this condition it is desirable, if high efficiency is to be obtained, that an Automatic Bar Replacement Magazine should be applied to the machine. Such a mechanism necessitates "opening" type stock tubes in place of the simple tubes illustrated at 40.

These "opening" type tubes are necessarily much heavier than the simple tubes, it is therefore arranged that the worm wheel 27 8 worm 26 usd to drive the camshaft 28 should be of extra heavy construction as also the Geneva Roll 29 Geneva Disc 8 integral gear so that they are well capable of transmitting the high torque required for rapid indexing.

The automatic lathe as described will have such a high rate of production that almost all users will need to change the tooling from production of one workpiece to another type relatively frequently. In order to facilitate this the following features amongst others have been incorporated in the construction:: All cams 7 are interchabgeable on any camshaft 17 or 28, detachable camshafts additional to those in use on the machine are supplied so that they may be fitted with spare cams ready for the next set up, latches hold the Bar Feed Tubes s Collet tubes in situ so that they can be readily removed and replaced, spare feed tubes are supplied so that they can be fitted with appropriate feed fingers ready for the next change over, struts are fitted adjacent the camshafts to hold the operating levers against spring pressure so that the camshafts can readily be removed 8 replaced.All quill Levers 8 Cross Slide levers can be operated manually during set up for trial purposes, adjustment endwise for final position of Quill tools to control finished sizes of workpieces is by simple Adjusting Box, similar facilitates are provided for cross slide tools, All tools will be of the pre-set type facilities being provided on the machine for this purpose.

One piece completely assembled Rotary Attachments make change over quick 8 easy as does also the permanent positioning of the driving cluster gears for the Attachment drives.

Figure 3 shows how a camshaft 41 and cams 42 together with Quills 43 and Operating Levers 44 can be arranged in the construction of a 5 Spindle Automatic Lathe in place of the vertical camshafts 17 as shewn in Fig. 2. This is a simpler s cheaper design than shewn in Figs. 1 s 2 for End working Quill operation but is limited to a 5 spindle for geometric 8 available space considerations.

Claims (1)

1. A multi spindle lathe consisting of a Workspindle Drum Headstock "1" accomodating a circular Indexable Drum "4" containing a number of journalled workspindles "5,' equally space around a pitch circle within the diameter of the Drum "4," this drum containing a gear mounted at the geometric centre of the workspindle pitch diameter driving gears "11" on each of the workspindles "5", a central shaft "9" carrying the geometrically mounted gear 10 being extended lengthwise into a Quill Housing "2" spaced longitudi nally from the Workspindle Headstock 1, the Quill Housing "2" accomodating a number of circular shaft type Tool carrying reciprocating Quills equal in number to the number of workspindles "5" such that tools mounted in the Quills "6" which latter are in alignment with the workspindles are capable of operating sequentially on work material carried by the workspindles "5" when these are rotating, the drive being characterised in that an extension of the central shaft "9," carrying the gear "1 0" which drives the workspindles through gears "11," is fitted with a gear "12" situated within the Quill Housing "2" and is in turn driven by a free running idler gear "1 3" the latter being mounted on a stationery sleeve "45" (Fig. 4) clamped within a bore in the Quill Housing "2," this bore being in alignment with one of the workspindles "5" when the spindle Drum "4" is in it's locked position.

2. A workspindle drive as claimed in Claim 1 characterised in that a train of gears "15" (Fig. 1) drives the free running gear 1 3, the train of gears comprising at least two gears which are changeable in order to change the speed of the central shaft "9" and in consequence the speed of the workspindles "5".

3. A workspindle drive as claimed in Claim 1 characterised in that the stationery sleeve "45" (Fig. 4) carrying the free running idler gear "13" accomodates a reciprocating tool carrying Quill "6" (Fig. 1) in alignment with a workspindle "5,' when the Spindle Drum "4" is in it's locked position.

4. A workspindle drive as claimed in Claim 1 characterised in that the central shaft "9" (Fig.1) is extended through the Quill Housing "2"''2'' 8 that this extension mounts a keyed cluster gear "35" adjacent the rear facing of the Quill Housing "2", the cluster gear "35" being arranged to drive gears mounted on the spindles of Rotary type Attachments such as High Speed Drilling, Screwing, Synchronous Pick up, these attachments being accomodated in the bores normally carrying non rotating type Quills 6, after these Quills have been removed.

5. A workspindle drive as claimed in Claim 1 characterised in that the freely mounted idler gear "1 3" mounted on an End Working Quill "6" lies within the Quill Housing "2" so that the outward facing of the Quill Housing is free s unencumbered making it possible to arrange the operation of the End Working Quills "6," Adjusting Links "20", Levers "1 8", Cams ' "7" 8 detachable cam- shafts "1 7" in a completely open s accesable manner so that these mechanisms can most conveniently be adjusted or changed by an adaptor, also after the removal of the detachable camshaft "1 7" the Levers "18" can be swivelled downwardly such that the Quills "6" can readily be removed 8 replaced by Rotary Attachments when these are required.

7. A multi spindle Lathe incorporating the free running idler gear "1 3" mounted on an End Working Quill "6" substantially as described and as illustrated in Figs. 1, 2, 3 & 4.