US2288254A

US2288254A - Spindle driving mechanism fob screw

Info

Publication number: US2288254A
Authority: US
Publication date: 1942-06-30
Anticipated expiration: 1959-06-30

Description

June 30, 1942. C. A. RICH VEIAL 2,288,254

SPINDLE DRIVING MECHANISM FOR SCREW AND SIMILAR MACHINES Filed Feb. 26, 1940 2 Sheets-Sheet 1 il kn-' .7 o 52- 92 i ms 9a O a a l Inv'entons June 30, 1942. c. A. RICH ET'A'L 2,288,254

SPINDLE DRIVING MECHANISM FOR SCREW AND SIMILAR MACHINES Filed Feb. 26, 1940 2 Sheets-Sheet 2 Patented June 30, 1942 AND SIMILARMA Charles A. Rich and William E. Twamley, Providence, R. 1., assignors to Brown and Sharpe Manufacturing Company, a corporation of Rhode Island Application February 2 6, 1940, Serial No. 320,752 12 Claims. (01. 74- 325) 1 The present invention relates to improvements in automatic screw and similar machines, and more particularly'to an improved driving mechanism for the work spindle.

The mechanism for driving the work spindle in machines of this general type conventionally comprises two driven elements, usually sprocket wheels or pulleys loose on the rotatable work spindle, and clutching means interposed between the driven elementsshiftable to cause the spindle to be driven alternatively by one or the other of them. These elements are continuously driven the spindle clutch for imparting the desired rateand direction of drive to the work spindle for the performance of successive operations of different character on the same piece. It will be understood that adjustments relating to the rate. and direction of .drive of the driven elements are made preferably in setting up the machine for i I the particular job, and not while the machine is in actual operation because of the relatively heavy weight and speed of operation of the driving connections.

In driving mechanisms of this type previously developed, thenumber of adjustments available both in the basic operating speed and in the ratio of operating speeds of the two driven elements in setting up the machine for operation upon widely divergent types of work, has been seriously clutch, and thereby to provide a machine which is well adapted for universal use in metal cutting.

limited by the complexity of mechanism and by the relatively great number of replacement parts required for effecting these changes; In the interest of avoiding such complication, it has been the usual practice to provide separate machines metals for which speed changes within a relatively fast range of speeds are required, andfor operating on steel and similar slow cutting metals in which speed changes within a much slower range of speeds are required.

It is a principal object of the present invention to provide a variable speed spindle drive adapted for use in machines of this general type, which is simplified and improved both in construction and mode of operation, and is readily adaptable for driving the work spindle over an extremely wide range of operating speeds, and in accordance with a considerably greater number of speed It is a further object of the present invention to provide in a variable speed spindle drive of this general description, a simple and readily accessible device for reversing the' direction of drive of one of the driven elements'on the work spindle with relation to the other, and in accordance with any desired ratio of rotating speeds of said driven elements as may be desired in accordance with the requirements of the work and the set-up of the operating tools in the machine.

More specifically, it is an object of the invention to provide a novel construction and arrangement of the mechanism for driving the two driven elements with their associated clutching means on the rotary work spindle, in which a maximum number of changes may be made in the driving rate of both driven elements, in the ratio of the driving rate of one driven element with relation to the other, and in the'relative direction of rotation of the two driven elements through the interchangeable location of exchangeable spur. gears in two pairs on appropriate driving centers for effecting all of the above noted adjustments.

With these and other objects in view, the several features of the invention consist the devices, combinations, and arrangement of parts hereinafter described and claimed, which together with the advantages to be obtained thereby will be readily understood from the following description taken in connection with the accompanying drawings, in which Fig. 1 is a view in front elevation of a portion of an automatic screw machine with a portion of thecasing broken away to illustrate particularly the spindle driving mechanism, only so much of the machine having been disclosed as is believed necessary to illustrate, the

, connection of the present invention therewith;

- for working on brass and similar 'free cutting ratios as determined by the position of the spindle 55 Fig. 2 is an enlargedidetail sectional view taken on the line 2--2 of Fig. 1, illustrating particularly the spindle driving mechanism located in the base of the machine; Fig. 3 is a plan View of the spindle driving mechanism shown in Fig. 2, but

with the reversible driving connections between the two spindle driving sprockets shown in a developed position for clarity of illustration; and

Fig. 4 is a detail sectional view on the line 44 one another.

dle clutch which may be of ordinary description ,keyed on the spindle, and arranged to be shifted axially into clutching engagement alternatively with either sprocket. It will be und'erstood that abelt and pulley drive may be substituted for the illustrated sprocket chaink and sprocket wheeldrive if so desired, the term wheel" as hereinafter employed in the claims being intended to cover the use of either a sprocketwheel or pulley The driven sprocket wheels are continuously driven by means of sprocket chains which pass around driving sprocket wheels forming part of the spindle driving mechanism located in the machine base. In accordance with the usual practice, applicants provide a large and a small driving sprocket wheel providing an initial ratio of fast and slow rotating speeds for the driven sprockets.

-driving mechanism has the advantage that a maximum number of changes may beeffected in the basic driving speeds of both driving sprockets,

I and also in the driving speed ratio between the driving sprockets by merely shifting the relative positions of the four gears comprising the two pairs. Furthermore, a single set of replacement gears may be employed to effect desired changes both in the basic driving speed of the large sprocket and the small sprocket driven there-- from, and also in the driving speed ratio between the two sprockets. In this manner, a very large number of speed changes are possible with a relatively small number of replacement gears. This may be illustrated as follows: with each machine it is proposed to provide twelve change gears, which gears in combination will render 132 available ,speeds. With this combination of gears, in other words, there will be available 120 .low speeds in combination with twelve high speeds.-

Another feature of the invention consists in a "simplified and improved arrangement of the spindle driving mechanism including the large and small driving sprocket wheels, their supportingshafts, and the change speed driving mechanisms which is simple and compact in construction, and is also readily accessible by the operator for the replacement of change gears of either pair. In accordance with this feature of the in vention, the two driving-sprockets are mounted on supporting shafts in axial alignment with Driving connections to the large sprocket. supporting shaft include a short power shaft and a-pair of change gears mounted in meshing relation respectively on the power shaft and large sprocket supporting shaft, these parts being located entirely at one side of the large struction and arrangement of the driving mechanismdn which the ratio change driving connections to the small driving sprocket supporting shaft pass through the axis of the large driving sprocket; there is the further advantage that the centers on which both pairs of change gears are mounted may be located relatively close together, so that relatively small gears may be em ployed, and a compact construction of the whole mechanism is achieved.

In accordance with another feature of the invention, applicants providea novel and eflicient mechanism particularly adapted for use in a spindle driving mechanism of this description for reversing the direction of drive of one of the driven sprockets on the work spindle. In the illustrated construction, a pair of ratio change gears are arranged to be mounted respectively on the small sprocket supporting shaft and on either of two lay shafts which are located equal distances from the axis of rotation of the small sprocket, and are continuously driven in opposite directions from the large sprocket supporting shaft. In the preferred form of the invention sprocket supporting shafts so that their centers form an isosceles triangle; .the drive from .the

- large sprocket supporting shaft being taken through a'gear on said shaft, a gear out of align- I ment therewith on one of the lay shafts, and a third gear on the other of said lay shafts of sufficient width for meshing engagement with both of said gears.

Referring more specifically to the drawings, Fig. 1' discloses .an automatic screw machine which may be of ordinary construction com'prising with a casing ID, a rotary'hollow' work spindle l2 having loosely mountedthereon two driven sprocket wheels l4 and I6 and a, clutch element l6 keyed to the shaft and arranged-to be shifted alternatively into clutching engagement with one or the other of said driven sprockets l4 and I6 In accordance with the usual practice in these machines, the position of the clutch I8 is automatically controlled from a cam shaft 20 and shift cam 22 by means of a cam actuated clutch shift lever 24 mounted on a stationary pivot 26 and having connection at its upper end with a clutch shifting collar 28-on the clutch member I6. Also shown in Fig. 1 is a tool carrying turret head 3|! and cross slide ways 32 of ordinary description. a

sprocket, and driving connections from one to the other of the sprocket supporting shafts located entirely at the other side of the large sprocket, and including a second pair of ratio change gears mounted respectively on a lay shaft driven from the large sprocket shaft and on the small sprocket supporting shaft. With this con- The machine drive is taken from an electric motor 34, to a driving countershaft 36, and thence by means of a sprocket 38 on the armature shaft of the motor, a sprocket chain 46, and a sprocket 42 on the countershaft 36. As shown in Figs. 1 and 3 of the drawings, the cam shaft 20 is driven from the countershaft 36 through driving connections which include a gear on the shaft 36, and a gear 'l6,.meshing therewith carried on a shaft 48. The shaft 20 is directly driven from the shaft .48 by means of a belt passing over a pulley 6| on the shaft 46 and a pulley 53 on the shaft 2|).

Applicants improved variable speed mechanism for driving the work spindle comprises a large driving sprocket wheel 52 connected by means of a sprocket chain 54 with the driven sprocket wheel I, and a small driving sprocket wheel 66 connected by means of a sprocket chain 66 with the driven sprocket wheel l6.

sprocket wheels

52 and 66 are rigidly mounted on supporting shafts and 62 respectively, as best The driving

ing shafts

88 and 62 are in axial alignment, be-

1185 64 in a bracket 66. The supporting shaft 68 is further supported at its outer'end in a ball bearing 68 formed in a wall 18 of the machine casing. The supporting shaft 62 is similarly supported at its outer end in a ball bearing I2 carried in a wall 14 of the machine casing. The

. large driving sprocket 62 and its supporting shaft ing shaft 62 are driven from the large sprocket supporting shaft 68 through driving connections which include two lay shafts 88 and 98 which are arranged in parallel relation to the aligned supporting shafts 68, 62, and with their centers equal distances from the shaft 68 in the form of an isosceles triangle. As will be further evident from shown in Fig. 3 of the drawings. These supporting supported at their adjacent ends in ball beara an inspection of Figs. 2 and 3, the power shaft I6 is also in alignment with the lay shaft 88, so

that the distance between centers of the power shaft 76 and large driving sprocket supporting shaft 68 is the same as that between the lay shafts 88, 98, and small driving sprocket supporting shaft 62. The lay shafts 88, 98 are continuously driven in opposite directions from the large sprocket supporting shaft 68 through gear connections comprising a driving gear 92 secured adjacent the right hand end of the shaft 88, a

gear 94 on lay shaft 98 arranged out of. alignmentwith gear-'92, and a gear 96 on the lay shaft 88 which is of the same diameter as gear 94, but is of sufiicient width for meshing engagement with both the driving gear 92 and gear 94. The small driving sprocket 56 and its supporting shaft 62 are arrangecr'to be driven alterna; tively in one or the other direction through the connections above described, by means of a pair of change gears 98 and I88, one of these gears,- as that indicated at 98, being mounted on a shaft 62, and the other of said gears, as that indicated at I88, being supported on either of the lay shafts -88 or 98, depending upon the direction of drive which is desired for the slow speed driven sprockwork in diameter is to be turned down and threaded to provide a screw thread having diameter and 10 'turns to the inch. In this instance a ratio of three to one is employed. The spindle speeds for the tumingand the subsequent threading operations are listed as follows:

For brass4150 R. P. M. and 1390 R. P. M.

For steel-870 R. P. M. and 290 R. P. M.

In Example 2, it is assumed that the work also in diameter is to be turned down and threaded-to provide a screw thread with 16 turns to the inch. In this example, a ratio of spindle speeds of five to one is employed; The actual spindle speeds for the turning andsubsequent threading operations are given as follows:-

For brass-4150 R. M. and 840 R. P. M. For 'steel--870 R. P. M. and R. P. M.

In Example 3, it is assumed that a worm thread is being out in diameter, and with twelve turns to-the inch. In this example where a fine finish is required, a ratio of ten to one is employed, the actual speeds for the. successive turning and threading operations being .listed as follows:

For brass-4150 R; P. M. and 415 R. P. M. For steel-1640 R. P. M. and 164 R. P. M.

.- ployed, it would be necessary to reverse the work direction to cause the die to back ofi the threaded portion of the work, such reversal being effected by the location of theselected spur gear I88 on the lay shaft 98.- r

It will be understood that the invention is not limited to the specific embodiment shown, and that various deviations may be made therefrom without departing from the spirit and scope of the appended claims. Q

-What is claimed is: I 1. For use in automatic screw and similar machines, the combination witha work spindle, a pair of driven elements loose on saidspindle, and means for clutching said driven elements alternatively to drive-the spindle, mechanism for continuously driving said drive'n elements including a driving element having connection with o'nedriven element, a se'conddriving ele-" ment having connection with the other driven ing-a pair of exchangeable spur gears for driving both of said driving elements from the prime mover at adjustable speeds, driving connections including a second pair of exchangeable spur gears locatable for'driving one of said driving elements at adjustable speeds in alternate directions with relation to the other driving element, and supporting centers for each pair of spur gears including alternatively available reverse driving centers for said second pair of spur gears. 5

2. For use in automatic screw and similar machines, the combination .with a work spindle, a pair of driven elements loose on said spindle, and means for clutching said drivenelements alternatively to drive the. spindle, mechanismfor continuously driving said driven elements including a driving element having connection with one driven element, a second driving element.

having connection with, the other driven element, a prime mover, gear connections including a pair of interchangeable spur gears for driving both of said driving elements from the prime mover' at adjustable speeds, driving connections including a second pair of spurgears locatable for driving one of said driving elements at adjustable speeds and in alternate directions with relation to the other of said driving elements, and sup-' porting centers for each pair of spur gears including alternatively available reverse driving element, a prime mover, gear connections includcenters for said second pair of spur gears, the supporting centers for each pair of spur gears including said reverse driving centers being arranged equal distances apart whereby all of said spur, gears are freely interchangeable to effect all of said speed and directional adjustments.

, 3. For use in automatic screw'and similar ma- .chines, the combination with a work spindle, a,

pair of driven'wheels loose on said spindle, and means for clutching said wheels alternatively to drive the spindle, driving means for said wheels ing shaft having connection with one of said driven wheels, a:smalldriving wheei and a supporting shaft in axial alignment with said large having connection with one of said driven wheels, iii

a second driving wheel and a supporting shaft having connection with the other of said driven wheels, means for driving said'first driving wheel and shaft including a pair of interchangeable spur gears, a pair of lay shafts arranged parallel to said second driving wheel supporting shaft and equi-distant-therefrom, means connecting 581d lay including a large driving wheel and a supportshafts to be driven by the first driving wheel supporting shaft in opposite directions, and a pair of exchangeable spur gears arranged on said second wheel supporting shaft and on either of said layshafts'in meshing relation for driving said 1 second driving wheel alternatively in opposite didriving wheel'and its shaft and having connection with-the other of said driven wheels, means fordriving said'large driving wheel and shaft, a lay shaft arranged parallel to said supporting shafts, gears connecting the lay shaft tobe tively to drive the spindle, driving means for said wheels including a large driving wheel and a supporting shaft having connection with one of said driven wheels, a small driving wheel and a supporting shaft in axial alignment with said large driving wheel and shaft and having connection withthe other of said driven wheels,

means for drivingsaid large driving wheel and. shaft including a power shaft, and interchangeable spur gears on said power shaft and on said large driving wheel supporting shaft in meshing relation, a lay shaft arranged parallel to said means for clutching said wheels alternatively to rections with relation to said first driving wheel.

'7. For use in automatic screw and similar machines, the combination with a work spindle, a pair of driven wheels loose on said spindle, and

drive the spindle, and driving means for said wheels including a driving wheel and supporting shaft having connection with one of said driven wheels, a second driving wheel and supporting shaft in axial alignment with said first driving wheel and shaft and having connection with the other of said driven wheels, means for.

driving said first driving wheel and shaft, a pair of lay shafts arranged parallel to said supporting hafts and equidistant therefrom, gears conchines, the combination with a work spindle, a

pair of driven wheels loose on said spindle, and means for clutching said driven wheels alternatively to drive the spindle, driving means for said wheels including a large driving wheel and a supporting shaft having connection with one of said driven wheels, a small driving wheel and a supporting shaft in axial alignment with said large driving wheel and shaft and having connection with the other of said driven wheels, means for driving said large driving wheel and shaft including a power shaft, and interchangeable spur gears on said powershaft and large driving wheel supporting shaft in meshing relation, a lay shaft arranged parallel to said supporting shafts, gears connecting the lay shaft to be driven by the large wheel supporting shaft,

and exchangeable spur gears arranged on the.

lay shaft and on the small wheel supporting shaft in meshing. relation, said power shaft and lay shaft being located equal distances from the axes of said supportingshafts to permit the interchanging of said pairs of spur gears.

6. In automatic "screw and similar machines,

the combination with a work spindle, a pair of driven wheels'loose on said spindle, and means for clutching said wheels alternatively to drive the spindle, and driving means for said wheels including a driving wheel and a supporting shaft necting the lay shafts to be driven in opposite directions from the first wheel supporting shaft, and exchangeable spur gears arranged on the second wheel supporting shaft and on either of said lay shafts in meshing relation to drive the small wheel shaft alternatively in opposite directions with respect to the first driving wheel and its shaft.

8. For use in, automatic screwmachine, the combination with a work spindle, a pair of driven wheels loose on said spindle, and means for clutching said driven wheels alternatively to drive the spindle, and driving means for said' wheels including a driving wheel and supporting shaft having connection with one of' said driven wheels, a second driving wheel and supporting shaft in axial alignment with said first driving w eel and shaft and having connection with the other of said driven wheels, a pair of lay shafts and a power shaft arranged parallel to said supporting shafts and equi-distant therefrom, gears connecting the lay, shafts to be driven in opposite directions from the first wheel supporting shaft, exchangeable spur gears arranged on the power shaft and on the first wheel' supporting shaft in meshing relation, and exchangeable spur gears similarly arranged on the second wheel supporting shaft and on either of said lay shafts in drive the spindle, and driving-means for said wheelsincluding a large driving wheel and a supporting shaft having connection with one of said driven wheels, a small driving wheel and a supporting shaft having connection with the otherof said driven wheels, means for driving said large wheel and 'shaftincludinga pairgoffinterchange-- able spur gears, a pair of lay shaftsarranged parallel to said small driving wheel supporting 2,288,254 shaft and equi-distant therefrom, gears connecting said lay shafts to be driven by the large driving wheel supporting shaft in opposite directions, and a pair of exchangeable spur gears arranged on said small wheel supporting shaft and on either of said lay shafts in meshing relationfor driving the small driving wheel alternatively spur gears. on the power shaft and on the large wheel supporting shaft in meshing relation, a pair of-lay shafts parallel to the upporting shafts eq'ui-distant therefrom and from each other, and

with one of saidlay shaftslin axial alignment with said power shaft whereby all of said spur gears are freely interchangeable, means for drivin opposite directionswith relation to said large driving wheel. p

10. For use in automatic screw and similar machines, the combination with a work spindle,

- a pair of driven wheels loose on saidspindle, and

shafts, gears connecting said lay shafts to be driven by the large wheel supporting shaft and in opposite directions, and exchangeable spur, gears arranged on the small wheel supporting shaft and on either of said lay shafts in meshing relation for driving the small driving wheel tionto the large driving wheel.

11. For use in automatic screw and similar machines, the combination with a work spindle,

alternatively in opposite directions with relaa pair of driven wheels loose on said spindle, and

means for clutching said wheels alternatively to drive the spindle, and driving means for said wheels including a large driving wheel and a supporting shaft having connection with one of said driven wheels, a sm'alldriving wheel and a supporting shaft in axial alignment with said large driving wheel and shaft and having connection with the other of said driven wheels,

means for-driving said large driving wheel andshaft including a power shaft, and exchangeable ing the lay shafts in opposite directions from the large wheel supporting shaft including a gear-on the large wheel supporting shaft, 9. gear on one of the lay shafts out of alignment therewith-,

and a gear on the other of said lay shafts meshing with both of said gears, and exchangeable spur gears arranged on the small wheel supporting shaft and on either of said lay shafts for driving the small driving wheel alternatively inopposite directions with relation to the large driving wheel. I

12. For use in automatic screw and similar machines, thecombination with a work spindle,

a pair of driven wheels loose onsaid spindle, and means for clutching said driven wheels alternatively to drive the spindle, driving means for said driven wheels including a'driving wheel-and a supporting shaft havingconnection with one of said driven wheels, a second driving wheel and a supporting shaft in axial alignment with said first-mentioned driving wheel and its shaft and having connection with the other of said driven wheels, a prime mover, gear connections including a pair of exchangeable spur gears and-driving centers for the same for driving said first-mentioned supporting shaft and wheel, and driving connection for driving the last-mentioned supporting shaft and wheel from the first-mentioned supporting shaft and wheel including a second pair bf spur gears locatable for driving said second shaft from ,the. first shaft at adjustable speeds and in alternate directions with relation to said first-mentioned supporting shaft and wheel, and alternatively available reverse .driving centers for-said second pair of spur gears.

CHARLES A. RICH. WILLIAM E. TWAMLEY.