USRE17477E - Grinding machine - Google Patents

Description

J. N. HEALD ET AL GRINDING MACHINE 2 Sheets-Sheet 1 Original Filed duly 14. 1922 I Nov. 5, 1929.

J. N. HEALD ET AL GRINDING mourns Nov. 5, 1929.

Original Filed July 14. 1922 2 sinus-Sheet 2 *9 4, the latter being driven at high. speed by" Reissued Nov. 5, 1929 UNITED STATES PATENT OFFICE JAMES H. OF WORCESTER, AND ALBERT TURNER, OF SHREWSBUBY, MASSA- CHUSETTS, ASSIGNORS TO THE HEALD MACHINE COMPANY, OF WORCESTER, MAS- SACHUSETTS, .A CORPORATION OF MASSACHUSETTS GRINDING Original no: 1,583,351, dated May 4, 1926, Serial No. 574,940, filed July 14, 1922.

' filed February 7, 1927. Serial No. 166,576.

The present invention relates to grinding machines. The invention resides in the novel combination and arrangement of parts hereinafter fully described, of especial utility in the constructionand operation of a grinding machine adapted to operate on cylindrical or similar surfaces, but equally applicable, in certain features, to a' grinding machine adapted to operate on internal or concave surfa s, or on plane surfaces.

In t e accompanying drawings,

Fig. '1 is a view inside elevation of such a grinding machine, according to the present invention.

Fig. 2 is an end view of said machine.

Fig. 3 is a top plan view.

Fig. i is an enlarged detail sectional view of the headstock of the machine.

Fig. 5 is a schematic view, partly in section, of certain fluid pressure devlces used for reciprocating the work.

Fig. 6 is a detail view of the oscillating valve member. a a

Fig. 7 is a detail view of the valve cap or closure. y Fig. 8 is a transverse sectional view of the fluid pressure control and reversing mech anism. I

Like reference characters referto like parts in the diiferent figures. v The improvements forming the sub ect matter of the present invention are here shown in connection with a plain grinding machine of the usual construction, embodying a suitable frame or base 1 which carries the usual wheel slide 9,; the latter being trans- I versely movable in ways 3, 3, provided by the machine frame. The slide 2 has journalled therein the spindle of a grindlng wheel -any suitable means, such as a belt 5 yvhich connects pulley 7;. The .on a shaftS,

. countershafting, likewise not shown in any event, the arrangement is such that the machine is self-contained as regards the drive of the grinding wheel 4, and the pull on the MACHINE Application for reissue wheel spindle by the driving devices is there fore downward, thus supplementing the weight of the wheel slide 2 in the mainte-. nance for the latter of a firm seat on the frame or base of the machine. The usual adjustment of the wheel slide 2 in the ways 3, 3 for the purpose of positioning the wheel. for different sizes of work is accomplished by a hand wheel 9 on the front of the machine, the'latter operating through a screw or other means, not shown, to obtain the crossfeed of the wheel 4. The wheel driving belt '5 1s caused to accommodate itself to the various positionsof the grinding wheel by a spring pressed tightener pulley 10, which is end, the machine frame provides longitudinal Ways 11, 11 for a sliding table 12, the movement of which, according to the present invention, is obtained by a fluid pressure controlling and reversing mechanism, of the type, for instance, disclosed in the co ing application of Drake and Hubbell, erial No. 528,118, filed January 9, 1922. As shown in Fig. 5, and as disclosed in detail in the aforesaid copending application, the table end- 12 is suitably connected, as. by a vvrod 13, to a doubleacting piston 14, contained in a fluid pressure cylinder 15.- The piston 14 is actuated by the admission of fluid under pressure to one end or the other of the cylinder 15, the fluid pressure being forced by a pump 16into a supply pipe 17 which delivers to a forming no part of the present invention, is described and claimed in said copending ap- -va1ve device 18, the construction ofwliich,

plication. The valve device 18 comprises a rotatable reversing valve member 57 (see Figs...61'and 8) keyed to a shaft 58, a stationary member 59 having ports 60 and 61 and a valve cap 62 (seeFig. 7 having ports ,63 i and 64. Port 60 is'in communication with.

return pipe 65 whereas port- 61 is in communication with supply pipe 17. Port 63 is in communication with pipe 19 and port 64 with pipe 20. The relation of members 59, 57 and 62 is clearly shown in the sectionalview Fig. 8, and if we assfime that valve' member 57 of Fig.6is projected without axial displacement onto stationary member 59 of Fig. 5, then the controlling devices for the table 12 are in the neutral, position. Valve member 57 has three passes 66, 67 and 68.

Pass 66 is always in communication with port 61 and so receives, at all times, the fluid entering at port 61. In the above described neutral position, pass66 is also in communication with both ports 63 and 64 and at the same time passes 67 and 68 communicate with port 60 and also with ports 63 and 64. In this neutral position, then,

the fluid will be shunted frLm pipe 17 through pass 66 to ports 63 and 64 through passes 67 and 68 to port 60, thence back by' return pipe 65. At the same time, both pipes. 19 and 20 are connected throu h ports 63 and 64 to the freely moving flui so that the fluid in cylinder 15 will not be constrained and the table 12 may therefore be moved by hand.

A lever 21 is also keyed to shaft 58, the upper end of this lever being fitted with a knob or handle, or the like. Assuming now that the lever 21 is moved to the position shown in Fig. 1, the valve member 57 will be I rotated in a clockwise direction, thus breaking the connection between pass 67 ar port 63 and also breaking the connection between pass 66 and port 64. It will be obvious then that the only outlet from port 61 for the fluid will be by way of pass 66 to port 63 and pipe 19, which will cause the piston 14 in c" linder 15 to move to the right carrying t e rod 13 and table 12. This will force fluid at theright of piston 14 out of cylinder 15 through pipe 20 entering port 64 where it is constrained to pass through pass 68 to port and so back by way of return pipe65. It will be obvious, without further description, that movement of handle 21 to the left and consequent rotation of valve member 57 dogsengage the in a counterclockwise direction, causes fluid to enter cylinder 15 by way of pipe 20 and leave cylinder 15 by way of pipe 19, because of the symmetrical arrangement of members 57, 59 and 62.

As described, the reversing valve device 18 is operable, as shown in Figs. 1 and 8 herein, by the direction control lever 21, the

"latter having a disengageable pin 69,.Znormally located in a slot of 'a rocking mem-' ber 22 whose upper 'end projects intoflthe path'of a pair of adjustable dogs 23 and 24 carried by the ta le12. These .stops or ember 22 alternately, whereby to reverse the direction of travel of the table 12 at each engagement; their longitudinal adjustment determines the throw, or

dogs:-.. Member 22 is pivoted on shaft 71 and also has connected to it a plunger 72 forced downward by a spring 73. The end of plunger 72-is V shaped and operates in connection with a stationary cam member 74, whereby to snap member 22 quickly to the right or left after it crosses the central or vertical position.

Mounted on the reciprocating table 12 are the usual worksupporting devices, here shown as a head stock 25 and a tail stock 26, the same providing suitable centers 27, 27 for the support between them ofthe work. The head stock 25 and the tail stock 26 are both directly supported for longitudinal adjustment in suitable ways 28,- provided by a member 29,

the latter adapted to swivel bodily-on the table 12 in order to vary the angularity of the axis of the work, ,in the presentation of same to the grinding wheel 4.

For procuring rotation of the work on the axis provided by the centers 27 27 the head stock 25 supports and carries an adjustable speed electric motor 30, the shaft 31 of which, as shown in Fig. 4, has a worm gear connection 32 with a countershaft 33, the latter being suitably journalled in the head stock and adapted to impart rotation by the worm gearing 34 to a driving plate 35, coaxial with the centers 27, 27 and engageable with the.

ly, the starting button 37 is'engaged, thus causing the motor 30 to impart'rotation to the work at a speed which is determined by the positionof the control lever 40 of a speed adj usting device 41 in the circuit of motor 30. In

this position of lever 36, a valve 42 inthe fluid pressure supply pipe 17 leading to valve 18 is held open by alink connection 43 with said lever36. Also, by means of 'a link connection 44, a valve 45 in water pipe 46 is moved into open position, as shown in Fig. 2, thus insuring a supply of water for,the grinding operation. When the lever 36 is thrown inwardly to engage the button 38 for topping the motor 30, the valves 42 and 45 ar losed by their respective links 43 ajnd'4 4; this shuts ofi the pressure fluid, thus stopping the movement of table 12, and at the same time prevents wastage of water afterthe discontinuance of grinding.

For the dressing and truing of the wheel 4;, by means, mond 47 on the tail-stock 26, the above described control mechanism affords special advantages; by holding the lever 36' in an intermediate position, so as not to engage the running and thus the work, during the pediate position of the lever 36 is accompanied by a partial opening of both the valves 42.

. and 45, through their respective link connections 43 and 44; this insures a supply of water for the wheel during the dressing operaof the table 12to carry the dresser 47 back and forth in contact with the periphery of the wheel. It is to be noted that this last-named result is obtained, through the medium of valve 42, without in any way disturbing the predetermined setting of speed control valve 48, associated with the reversing valve device ,18 and manually adjustable, (by its attached handle, Fig. 8), as described in the aforesaid copending application of Drake and Hubbell, to controlthe speed at which the table 12 is moved back and forth during any given grinding operation. As a result of this, after the wheel has been dressed, the grinding operation can be resumed at the same speed previously determined upon, since the full completed movement of lever 36 into contact with starting button 37 causes valve 42 to move to its wide-open position.

In the use of the machine for grinding by straight inward cuts, involving no reciprocation of the Work in contact'with the wheel, it

is necessary only to shut off the valve 48 completely, thus discontinuing the fluid pressure supply. Thereupon, the movement of lever 36 to starting position insures the desired supply of water for the grinding. operation and also insures the desired rotation of the work,in the absence, however, of 'any table travel whatsoever.

As shown most clearly in Fig. 5, .the'inVention affords an automatic meansgfor insuring a lowered speed of travel for the table, just prior to reversal thereof; the lowering of the speed taking place at that moment when the plunger 72 reaches the apex of the stationary cam member 7 4, at which instant the rocking member 22 is about to spring to lts extreme position'to definitely make the pressure fluid active on the other side of the piston to reverse the direction of travel of the table. In this manner the detrimental shocks incidental to reversal at high speeds are avoided. For this purpose is provided a' lever 49, pivoted at 50 to the fixed framework, and carrying on its free end, adjacent to the rocking member 22, a roller 51. {Said roller 51 for instance, of a suitable, diastarting button 37, the motor 30 is kept from,

riods when the Wheel is being dressed, is not sub ect to rotation. However, this interme- .of its stroke.

tion, and also, a throttled-down reciprocation stroke by said ta le.

lies in the path of inclined cam surfaces 52 and 53 formed, respectively, on the table dogs 23 and 24. Thesurfaces 52 and 53 are so disposed, with relation to the dogging surfaces proper, as to make contact with the roller 51, during the reciprocations of table 12, just prior to the engagement of member 22 by one or the other of saiddogging surfaces. In this way, just before each reversal of the table, the free end of lever 49 is depressed; in consequence of which, by means of link 54, a valve 55 in fluid pressure supply pipe 17 is partially closed. This throttles the fluid pressure supply, and thus decreases the speed of travel of the table, as the latter approaches each end This automatic speed reduction insures a smooth reversal of the table, with a uniform amount of over-run at each end of the stroke, since the speed imparted just before reversal is invariably a lowered. speed of travel, regardless of the s This is especially. valuable in the grinding of long work of relatively small diameter,'where a high table speed is required for efiicient operation and where the problem of smooth reversal is a difficult one. Furthermore, this slowing up of the table travel is most desirablewhcnever is to be encountered at the end ofthe surface being ground, since it prevents the withdrawal of the work in the absence of a complete revolution in contact with the wheel at the a shoulder point of reversal and thus insures the production of a true diameter at that point.

As shown-in Fig. 1, the machine provides,

in addition to the motor starting button 37 (normally operated by the lever'36) a start ing button 56, which is so connected in the motor circuit with the speed adjustment device 41 as to produce, when held depressed,

a very slow rotation ofthe motor 30. This allows the driving plate 35 to be brought to any desired position, for facilitating the disposal in the machine, or the removal therefrom, of work that is, for various reasons, difficult to handle.

ton 56 pressed in, for testing purposes, or to determme whether or not 1t 1s runnlng true,

or whether it has been sprung in the grind-.-

means operable by fluid-pressure for reciprocating said table, an electric motor carried by said table for rotating the work, and a In addition, the work may be made to rotate slowly by holding this but- 'said table, anelectric motor carried by said starting and stopping lever for said motor, adapted to control, simultaneously, the fluid pressure supply. a

3. In a grinding machine, the combination with a table for supporting the work, of means operable by fluid pressure for reciprocating said table, an electric motor carried by said table for rotating the work, and a levermovable into opposite positions for respectively starting and stopping said motor and opening and closing the fluid pressure supply, said lever, in an intermediate position, adapted to throttle said supply without starting said motor.

5. In a grinding machine, the combination with a table for supporting the work, of means operable by fluid pressure for reciproeating said table, an electric motor carried by said table for rotating the work, a grinding wheel, means for supplying water to said wheel, and a lever movable into opposite positions' for respectively starting and stopping said motor and opening and closing the fluid pressure supply and the supply of water to said wheel, said lever, in an intermediate position, adapted to throttle said fluid pressure supply and furnish water to said wheel without starting said motor.

6. In a grindin machine, means operable by fluid pressure or reciprocating the work, a control device adjustable to vary the speed of said reciprocation, an electric motor, re:

- ciprocating with the work, for imparting rotation thereto, and a starting and stopping lever for said mot-or adapted, in an inter- .mediate position, to throttle the speed ofreciprocation of the work, independently of the setting of said control device, and without starting said motor. I

7. In a grinding machine, a table adapted to be 'reciprocated by flpid under pressure, a reversing valve for the pressure fluid, connections, including dogs on said table for actuating said reversing valve,-*throttling valve means separate from said reversing valve, and means on said table adj acent said dogs to actuate said throttling valve means, said .last two means being adapted to check the flow of fluid just prior to the actuation of said reversing valve by saidflogs, whereby a high speed table may be reversed with a small but definitely fixed overrun, said table resuming speed immediately after reversal,

8. In a grinding machine, a table reciprocab'le by fluid under pressure, a reversing valve for the pressure fluid, dogs on said table for operating said reversing valve, thereby to procure the reversals of said table, a second valve independent of said reversing valve for the control of said pressure fluid,

and means on said table adjacent said dogs.

for actuating said second valve to reduce the flow of pressure fluid slightly in advance of .each actuation of said reversing valve by said dogs, thereby to lower the speed of said table at a moment prior to each reversal of its travel. a

9. In a grinding machine, a table re- 1 sure fluid, and-,meansoperated by'said table for actuating said second valve to reduce'the flow of pressure fluid slightly in advance of each actuation of said reversing valve by said dogs, thereby to lower the speed of said table at a moment prior to each reversal of its travel.

10. In a grinding machine, a reciprocable table, fluid pressure means employing a substantially non-compressible fluid for operating said table, a reversing valve for said fluid, means for operatin said reversing valve to procure reversals 0 said table, and means to decelerat-e the table to given low speedatthe moment that the reversing valve first produces an efl'ect on the fluid under pressure in the act of reversing the motion of the table, said decelerating means acting through control of the'fluidunder pressure and having an unvarying' effect on the table to enable the length of the table stroke to be maintained at an adjusted length despite variations in speed of the table travel between the limits of the stroke.

stantially non-compressible fluid for operating said table, a table reversing member, table dogs adapted for coaction with said reversirig member for reversing the direction 0 travel of said table, a reversing valve actuated by said reversing member, and means automatically acting on the fluid under pressure and effective at that moment when the reversing valve first starts to exert its efl'ect upon'the fluid to bring the flow of fluid operating the table to a definitelow volume.

12. In a grinding machine, a reciprocable table, fluid pressure means employing a substantially nonscompressible fluid for operating said table, means for reversing the direction ofgtra'vel of said table, and means'op erating ohithe flow'of fluid under pressure priorlto the reversalthereohfor causing itto operate the tixblethiough agiven range of speed in its negative acceleration 'prior to the reversal thereof, thus to maintain a predetermined length of the stroke of said table notwithstanding variations in table inertia due to changes in table speed.

JAMES N. HEALD. ALBERT TURNER.

Images