US1508965A - Grinding machine - Google Patents

Description

Sept. 16, 1924.

-A. M. DRAKE GRINDING MACHINE Filed Dec. 21, 1922 the usual head, in which is journalled' a ro-- Patented Sept. 16, 1924.,

1? TATE ALDEN M. DRAKE, OF WORCESTER, MASSACH USETTS, ASSIGNOR TO THE HEALD' MACHINE COMPANY, OF WORCESTER, .MA SSACHUSETTS, A CORPORATION -OF MASSACHUSETTS.

GRINDING MACHINE.

"Application filed. December 21, 1922. Serial No.608,182.

To all whom it may concern:

Be it known that I, ALDEN M. DRAKE,

a citizen of the United States, residing at Worcester, in the county of Worcester and Commonwealth of Massachusetts, have invented a new and useful Improvement in a Grinding -Machine, of which the following, together with the accompanying drawings, is a specification.

The present invention relates to grinding machines. The invention contemplatesan improved belt drive between an overhead line shaft and the grinding wheel spindle, so arranged as to insure adequate belt wrap on said spindle, and the maintenance of proper tension in the several belts,lin all positions of operation of said wheel. The

above and other advantageous features of my invention .will hereinafter more fully appear, reference being had to the accompanying drawings, in which-.

Fig. 1 is a view in rear elevation, showing a grinding machine embodying my invention.

Fig.2 is an end view, partially in section, of the machine shown in Fig. 1.

Like reference characters refer to like parts in the different figures.

For purposes of illustration, the invention is shown herewith as applied to an in ternal grinder, the base 1 of which carries tatable work spindle 2. The spindle 2 serves for the support and rotation of the work and is adapted to be driven at a moderate speed by means of a pulley 3, on in any other suitable manner.- Thebase 1 is provided with longitudinal ways 4, a, for slid'ably supporting a table 5 which carries a rotating grinding wheel 6. Longitudinal movement of the table on the base causes the wheel 6 to traverse the rotating work, thus procuring in a manner well known in the art, a uniform grinding action over the entire interior surface of therecess or hole'in the work.

The grinding wheel 6 is hereshown as mounted on the end of a spindle 7, which moves with the table 5 and is provided with a pulley 8, whereby the spindle 7 may be driven at high speed by means of a belt 9. The belt 9 connects the pulley 8 to a pulley 10 on a countershaft 11, upon which is mounted a second pulley 12 carrying a belt 18 passing upwardly to the usual elongated 'drum, not shown, on an overhead line shaft.

In the particular machine heroin illustrated, provision is made for a cross feed of the grinding wheel 6 in a direction transverse to the,line of movement of the table 5, and to this end the wheel spindle 7,

together with its driving devices adjacent thereto, is supported u on a cross slide 14,

.the latter being mo-va le transversely on suitable ways 15 provided on the table 5, as by means of hand-wheel 14'.

To the cross slide 14 is adjustably secured a bracket member 16, having an upwardly 'extending portion 17 overhan ing the base 1 and table The counters raft 11, carrying the pulleys 10 and 12 is journalled in an arm 18, which is pivotally mounted on the portion 17 of the bracket 16 w means of a pin 19. The arm 18 is provided with a lug 20 having openings 21 for receiving a chain 22. The chain 22 is retained in one of the openings 21 by means of a set screw23, the end of which is ada ted to engage one of the links of the c ain 22. The chain 22 passes downwardly from the lug 2O overa pulley 2/1 carried by the bracket 16, and its end is attached to a spring 25. The other end of the spring 25 is connected to the cross slide 14 by means of a pin 26, so that thespring 25 tends-to exert a downward pull on the arm 18'carrying the countershaft 11.,

The belt 9 in engagedby an idle or tight-. ener pulley 27, carried at the end of an arm 28, the latter being pivotally mounted on a pin 29 which is carried by the-bracket 16. As shown in Fig. 2, the pivot pin 29 is surrounded by a coil spring 30, one end of which is secured to the bracket 16 by a stud 31, and the other end of which is seated in one of the several 'holes 28 provided in the arm 28 and tends to turn it in a clock Wise direction about its pivotpin 29, so that the pulley 27 is adapted at all times to take up any looseness in the belt 9, and also to insure the adequate wrap of said belt around the wheel spindle pulley 8.

From a consideration of the foregoing, it is apparent that by my invention I have provided an improved arrangement whereby both of the belts which transmit power from the line shaft to the wheel spindle 7are at all times maintainedat the proper tension, the one independently of the other. The belt 13 is always held taut by the action of the spring 25 which tends to pull the arm 18 downward. At the same time, the pulley 27 eliminates any slack in the belt 9 by the action of the spring 30 tending to throw the arm 28 in a clockwise direction. The belts 9 and 18 willalso always be held at the proper tension irrespective of the shifting of the cross slide 14, as the grinding wheel 6 is fed transversely with respect to thework. It therefore follows that a grinding maching embodying my invention will always operate in a uniform manner, owing to they fact thatthe speed of the tool spindle 7 remains constant and is not subject to fluctuations, due to changes in the belt tension as the cross slide 14 is shifted during the operation of the machine.

exerted by the springs and 30, rcspecr,

The exact amount of tension of the belts 9 and '13 may be closely regulated by the means provided for adjusting the forces tively. The effective length of the chain 22 is determined by the particular link which is engaged by the pin 21, so that the pressure exerted by the spring25 on themay be adjusted by causing the end of the spring 30 to engage in different holes 28 provided on the arm 28. By the adjustments above described, a proper balance can be obtained between the forces exerted on the countershaft 11 and the idler pulley 27 which will be maintained throughout the operation of the machine, as previously set forth. The bracket 16 can be moved bodily on the cross slide 14 by reason of its connection thereto by a foot 82 received in a slot 33, whereby the belting can be adjusted when set-ting up the machine, in 'ad vance of ,the more delicate adjustments of the spring-s25 and 30.

I claim,

In a grinding machine, a base, a table longitudinally movable thereon, a grinding wheel spindle carried by said table and adjustable crosswise thereof, and means for driving said spindle from an overhead line shaft, said driving means comprising a belt driven counter-shaft which is belted itself to said spindle, incombination with a spring drawing downwardly on said countershaft,

and abelt tightener acting on said spindle belt, the latter providing a wrap around the spindle pulley in all positions of cross wise adjustment of said spindle.

Dated this 15th day of December; 1922.

ALDEN M. DRAKE.

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