US1432626A - Thread-milling machine - Google Patents

Description

C. H. SCHURR AND E. J. LEES.

THREAD MILLING MACHINE.

APPLICATION FILED IAN. I2, 191s.

Patented Oct. 11.79 1922.

4 SHEETS-SHEET I.

I III Ilia! N IIII EM!" IIIIIIII.. @G l C. H. SCHURR AND E` l. LEES.

THREAD MILLING MACHINE. APPLICATION FILED IAII.I2, 191s.

1942962@ Pammed @on E7, R922@ 4 SHEETS-SHEET 2.

I "Ifa I f `IIIx III I IIIII IIIIIIIII IIIIIIIIII by Mal' mijl.

In.. Il lll C. H. SCHUHE AND E. l. LEES.

THREAD MILLING MCHHL.

APPUCMION HLED1AN,12,1918.

L, atented Oct. L?, 1922i,

SHEES-SHEET 3.

C. H. SCHUHE AND E. 1. LEES.

THREAD MILLING MACHINE.

APPLICATION FILED IAN. I2. ISIS. 194393 @$36. Fatemi-ed Oct. I?. 1922.

'Patented @et i7, 1922..

narran eras hddttt PATENT @FFEQO CHARLES H.y SCHURR AND ERNEST J'. LEES, 0F CLEVELAND, OHIO, ASSIGNQBS T0- THE LEES-BRADNER C0., OF CLEVELAND, QHIO.

. waan-MILLING atacante.

rll`hread-Milling Machines, of which the following 4is a specification, the principle of the invention being herein explained and -the best mode in which we have contemplated applying that principle, so as to distin ish it from other inventions.

ur invention pertains to improvements in a thread milling machine and more particularl. to changes in the relatlve arrangement, shape and function of certain parts .which either mechanically. coact with the lead screw or have. some other practical indirect association therewith.

The improvements declared by this application are four in number, first, an arrangement which places the lead `screw directly underneath longitudinal ways upon the bed of the machine so that such screw is sheltered and protected from above particularly against the deposit of grit and other sediment, the collection of which is attendant upon the working operation of the machine; second, the provision of an independent longer and more durable thrust bearing for the lead screw which is located between the two -end bearings ordinarily till now relied upon; third, an arrangement whereby a saddle which carries the-swivel head and is automatically moved by the lead screw is caused to have telescopic connection with the tail stock so that the relative longitudinal movement of the two is considerably increased; fourth, the provision of duplex means for controlling.the operative connection of the lead screw and saddle, especially in the provision of means for absolutely locking the two together in addition to the frictional hold upon which reliancev has heretofore been placed.

With the foregoing and other objects in view the invention consists of the novel construction, combination and arrangement of parts as hereinafter more specifically described and illustrated in' the accompanying drawings, wherein is shown an embodiment of the invention, but it is to be understood that changes, variations and modifications can be resorted to which come vwithin the scope of the claims hereunto appended.

Adverting to the drawings:

Figure I--is a front elevation of a thread millin machine embodying -our invention with t e tail stock in a certain position.-

Fi ure II is a corresponding view showing t e tail stock moved to a position somewhat nearer therhead stock to exemplify its telescopic association with the saddle.

Figure-Hl is a partial plan view of that portion of the machine which includes the telescopic arrangement of the saddle and tail stock illustrated-in Figure H.

vFigure IV is a vertical cross-section of the machine showing the position of the lead screw directly underneath the ways formed upon the longitudinal front.

Figure V is a right end view showing parts of the tail stock in section whereby the telescopic connection is otherwise revealed.

Figure VI is an enlarged vertical crosssection on line VI-VI of Figure I showing certain operative parts in end elevation with thev swivel head removed.

'Figure VH is a vertical longitudinal section on line VI-VII of Figure VI.

Figure VIH is an oblique-section on line VIII-V IH of Figure Vl.

rIhe machine is supported upon a suitable bed 1 provided above with a sli-deway 2 along the longitudinal front of the bed. An interjacent area of the slideway -is formed as an upwardly projecting guideway 3. rlhe purpose of .both ways will hereinafter appear. One end of the bed supports the head stock 4 on which atrain of gearing designated entirely by the numeral 5 communicates power to a lead screw 6 which extends the entire length of the machine and is supported at opposite ends thereof in suitable bearings 7 and 8. Inasmuch as the manner of making the head stock so as to effect the harmonious I against poa-` disposition thereupon of chips, grit and sediment which would be likely eventually to in-Y jure the threads thereon. This feature while simple is a useful practical advantagev and The end thrust required to be reckoned within the lead screw bearings has frequently occasioned trouble, partly because of its occasional severity and partly because at the location of the bearing which I have designated by the numeral. 7 insufficient space was afforded for the accommodation of an end thrust. bearing large enough and strong enoughto meet the needs. Vitli this in'mind we havethought to provide auxiliaryend thrust bearing surfaces between the bearings 7 and 8 which are sufficiently removed in a direction toward the tail stock. The construction. comprises a pair of spaced collars 9 which are pinned to the shaft 6 on opposite sides of the additional end thrust bearing 10. Brass washers 11 also appear interposed between the faced ends of the bearing and the collars.

Movable upon the guideway 3 is a saddle 12 adapted to support the swivel cutter 4head inl conformit with the idea which constitutes the third feature of our invention.

That end of the saddle 12 which is furthest from the head stock 4 is beveled off at 13. A tail stock 14 is movable upon the slideway 2 and owing to itsbeing hollowed at 15 is enabled to straddle the smaller end 13 of thev saddle or to have what is in the nature of a telescopic .fit therewith. The advantage of such van arrangement is that the tail stock may be mcved considerably nearer the head stock 'Witheet interference with the saddle. of the tail stock are indicated in Figures I and II respectively andthe manner in which the tail stock is intersectedfby the reduced extremity of the saddle will be further evidenced upon inspection of Figures III and V. The movement of the tail stock may be accomplished in the ordinary way by turning a hand wheel 16 which in turn rotates a pinion 17 in engagement with a rack 18' which is carried along the front of the machine.

In machines of this character it is desired frequently to reverse the cutter head independentlyof the :automaticV drive or longitudinal traverse movement thereof by mea-ns of the lead screw. To this end it has beenv common in the art to loosen certain parts so as to enable idle movement ofthe supporting saddle irrespective of any movement on the part of the lead screw. Till now, so far as our knowledge extends, this was accomplished by the loosening of a frictional hold which obtained during the automatic working traverse as between the lead screw and a coacting internally threaded The two nearl v extreme ositions sleeve carried by the saddle. We'have discovered that such frictional hold was necessarily coarse and insufliciently reliable where absolute precision was desirable or necessaryk and'laccordingly have provided an additional 'firmer connection between the lead screw valso .the frictional. engagement 'is suilicient because the cuttingengagement is less severe when the frictional engagement is to be relied upon. Suppose a piece to have been cut. taken out and found not `'small' enough, necessitating that it be placed back on the machine 'for recutting. No identification marks being on the shaft the relation of the threads to the position of the cutter is'not correctly ascertainable. The precise position. of the cutter is not known. In such a case the positive or lock connection is re leased and the nut rotated'so as to move the cutter lengthwise ofthe bed and then after it is properly located the frictional hold will answer satisfactorily because the subsequent finishing cut is comparatively fine. Rotatably mounted in a hanger depending from the saddle 12 is an internally threaded sleeve 19 adapted to cooperate with thelead screw 6. This sleevefis anged at one end at 20 and such flange carries'on one side a beveled gear 21 and on theother side an auxiliary sleeve 22 the fixed relation being effected by means of pins 23. The auxiliary sleeve 22 is provided with circumferential notches 24 seen in Figures VI and VIII, the purpose of which will hereinafter becomey apparent. In screw threaded connection with a boss 25, formed on the under side of the hanger, is an adjustable nut having the outer end of its stem provided with a handle 26, the inner endl of which is adapted to engagea clamping shoe 27 disposed in a suitable slot 28 and movable into and out of an annulan 115 groove 29 fashioned in the sleeve 19. By'. this arrangement the clamping shoe 27 may be caused frictionallyto engage the sleeve to prevent its rotation and therefore to cause its axial movement whenever the lead screw 120 y6 turns. l A thumb screw 30 passes through a projection 31 on the hanger in such a manner that the inner extremity 32 of the screw may be entered into any one of the circumferential notches 24 and thereby the addi- 125 fore a bevel pinion 35 which is carried'on 130 the opposite end of the shaft in mesh with the beveled gear 21. This is the usual contrivance by means of which, after the sleeve 19 is loosened. it may be rotated about the screw so as to accomplish the return of the saddle in a direction toward the tail stock.

The arrangement according to which the lead screw is disposed directly underneath the guideway 3 cf the saddle 12 eases and perfects the action which determines the lead because the thrust therealong is more nearly parallel owing to the fact that the lead screw is in the same vertical plane as the center line of the saddle. In this Way accessibility, durability and accuracy are had. Less friction is encountered where the guideway and slideway are brought close together particularly when superposed as We have disclosed than if they were separated so that one` was along the front of the machine and the other along the back thereof.

lVe claim:

l. A thread milling machine comprising a bed formed with Ways, Work and tool holders thereon, a saddle supporting one of said holders and movable upon said Ways. driving means, a lead screw operatively connecting said driving means Wit-h said saddle, friction means for controlling said connection and distinct means adapted to lock said connection.

2. A thread milling machine comprising a bed formed with Ways, Work and tool holders thereon, a saddle supporting said too] holder and movable upon said Ways, an internally threaded sleeve mounted in said saddle, driving means, a lead screw cooperating with said sleeve and operatively connected with said driving means to effect the automatictraverse of said saddle, amd a locking device including parts carried by said saddle and sleeve respectively to secure the same together.

3. A thread milling machine comprising a bed formed with Ways, Work and tool holders thereon7 a saddle supporting said tool holder and movable upon said Ways, an internally threaded sleeve rotatably mounted in said saddle and fashioned With circularly arranged notches, driving means, a lead screw cooperating With said sleeve and operatively connected with said drivin means to effect the automatic traverse of sai saddle, means for frictionally binding said sleeve and saddle together, and means carried by said saddle and adapted to project into one of said notches whereby absolutely to lock said sleeve and saddle together.

Signed by us, this 28th day of December,

CHARLES H. SCHURR. ERNEST J. LEES'.

Images