US2192308A - Grinding wheel dresser - Google Patents

Description

March 5, 1940. F. GREINER ET AL GRINDING WHEEL DRESSER Filed Jan. 8, 1937 4 Sheets-Sheet 1 INVENTOR H oahN 2 2% M Mnm A AMM/ mcR.

March 5, 1940. F. GFi'ElNER ET AL 2,192,308

GRINDING WHEEL DRESSER Filed Jan. 8, 1951 4 Sheets-Sheet 2 INVENTOR Z4 FRANK RE/NEE Co/wenn L077 March 5, 1940. F. GREINER ET AL 2,192,308 GRINDING WHEEL DRESSER INVENTOR Fen/m GEE/IVER Comena L. Orr

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March 5, 1940; F. GREINER ET AL 3 GRINDING WHEEL DRESSER Filed Jan. 8, 1937 4 Sheets-Sheet 4 INVENTOR FRANK GEEINEB Comenn L.Orr

Rm. PM E Pmc I Patented Mar. 5, 1940 UNIT D STATES PATENT OFFICE amass ammo wnanr. mmssnn Frank Greiner, neuron, mm, and Conrad 1.

Ott and Ralph E. Price, Waynesboro, Pa, as-

signors to Landis'rool Company, Pm, a' corporation of Pennsylvania Waynesboro,

Our invention relates to truing devices tor grinding machines, and it is anobiect of same to provide means for truing the grinding wheel and compensating for wear thereon after a work piece has been removed from the machine.

A further object is to provide means operable upon removal of the work from the machine for initiating operation of the truing and compensating mechanisms.

7 A further object is to provide means whereby said truing operation is performed only after a predetermined number of pieces have been removed from the machine.

A further object is to provide means for eiiecting a taster traverse between the truing tool and the wheel in one direction and the 'slow traverse in the other direction.

Other objects will become apparent as the I description proceeds.

Figure 1 is a partial front elevation of a machine in which .our invention is incorporated.

Figure 2 is an end elevation of the mechanism electrical layout.

Figure 7 is a front sectional elevation of the rootstock operating lever. Figure 7A is a plan view showingthe rootstock partly in section and the lever for actuating same. Figure 8 is a front elevation partly broken away to show the ratchet and switch operating mechgnivsms for initiating operation the dressing e co.

In the drawings numeral ll indicatesthe bed of a grinding machine; il, a grinding wheel support slidably mounted thereon; and I2, a grind- I ing wheel rotatably mountedin said support. A work carriage III has been mounted thereon, a headstock Ill, and arootstock I02, a work piece ",in this case a camshaft is mounted between said headstock and said iootstock in the usual 7 manner.

In Figure 1 is a feeding movement 0! the grinding wheel comprising a hand wheel ll mounted on a hand wheel shalt i4, said hand wheel shaft having a bevel gear-l meshingwith another bevel gear I! on a vertical shalt ll. Said vertical shaft is connected to a feed screw It thru. gearing not shown. Said hand wheeland associated parts may be rotated intermittently by means of a ratchet/wheel i8 vactuated by apawl l9. Said along the lines section on the line H 0! ll igshowna mechanism for eflecting pawl is mounted intermediate the ends of an elongated piston 20. The ends otsaid piston are slidably supported in two cylinders 2| and 22. The means for directing fluid der pressure to the cylinders will be described later.

Figure 1 also shows mounted on a wheel tender 23, a mechanism for dressing e grinding wheel. As shown in Figures 2-5, inclusive, this mechanism consists of a base 24 attached to a portion of the wheel lender. Said base has a dovetail guide formed therein to receive the slide portion of a carriage 25; At the end of said base is attached a cylinder 26, havingisuitable fluid connections 21 and". A piston 29 in said cylinder is connected to carriage 25 thru piston rod to.

The means. for feeding diamond 2| comprises a holder 32 slidably mounted in a cylinder 13 which is integral with carriage 25. One end of said holder is bored out to receive a threaded bushing 34. A screw 35 is inserted in said bore in threaded engagement with said bushing. A screw adjusting mechanism is attached to said carriage and consists of a plate 88 in which are formed cylinders I! and it for receiving a piston 29 and cylinders and 4| for receiving piston 42. Said cylinders are arranged in parallel re-.

recessed where the end of screw 35 emerges and a ratchet wheel 44 keyed to the unthreaded portion 01! screw 35 is inserted therein. Said ratchet wheel may be actuated by pistons, 30 and 42 thru pawls 45 and 46, respectivelymounted in slots 4'! and 48 in said pistons and urged into engagement with said ratchet by springs 48 and 50. A hand wheel 5| keyed to the screw shaft provides means m1 manually actuating the screw 35. The amount of feed at each strokeoi the various feed pistons may be adjusted by means of stop screws 85, 86 and 81. A

A limit switch 52 mounted on-iender l2 isdepressed at the end 01' a dressing stroke in one direction by a cam 53. Said cam is attached to an arm 54 which is in turn-secured to plate 36.

The mechanism for initiating operation of the dressing mechanism consists of a footstock lever 60, Figure '7, and a normally closed switch 62, the function of which is to deenergize a solenoid 64 when said lever is moved to withdraw the rootstock center from a work piece. When said lever is shifted it may be latched in the new position by means of a key llll,which engages a slot III in a disk 2. Said disk is mounted on a stud H3 about which lever is also mounted. Key H0 is formed on the end of a lever H4 contact, with disk H2. A pin H1 is slidably in-.

serted in the handle H8 01 lever til. One end lation in said plate. Said screw 25 has an unthreaded portion extending thru plate and.

switch operating mechanism is attached to ratchet I20 and consists of a disk 61 having mounted on its periphery a series of removable spaced studs 61'. A segmental cam'65 is loosely mounted on stud I 2|. Said cam carries a pawl I23 pivotally mounted thereon and urged into contact with the teeth of ratchet I20 by a spring I23. Another spring I24, one end of which is attached to said cam and the other end to panel I22, serves to reset the cam and pawl after each impulse. A stationary pin I30 limits the reset movement of cam 65. A spring I25 attached to said panel engages said ratchet wheel and acts as a detent to prevent backward movement of said ratchet. Solenoid 64 is attached to said segmental cam by a link I26 pivotally attached thereto by a stud I2I. An extension I28 of said link is shaped to conform to the periphery of ratchet wheel I20 and is moved into contact therewith as cam 65 is rotated by solenoid 64.

Said extension actsto lock said ratchet at this point and prevents an overrun thereof.

An operating arm I32 on switch 66 carries a roller I3I normally in engagement with the. pe-' riphery of disk 61 or studs 61'. When said roller is in contact with the periphery of said disk a circuit is closed thru said switch to energize solenoid 68. When said roller engages one of the studs 61, the circuit thru switch 66 is held open. A smaller roller not shown is mounted on the same stud as roller I3I in position to be engaged by cam 65 on its working stroke to lift said roller I3I out of contact with said disk or said studs and open the circuit thru switch 66.

Operation v When the operator pulls footstock lever 60 to release a work piece 6|, a latch holds it in release position. A button :62 on said lever engages switch 63 and opens the circuit to deenergize to open the circuit which it controls so that foot stock lever may be released and switch 63 closed without again energizing solenoid 64. Fluid under pressure for operating the dressing mechanism and thewheel feed mechanism may be supplied by any suitable means thru line 69 to valve I0. Said valve may be actuated in one direction by solenoid 68 and in the other direction by a spring 'II. When solenoid 68 is energized as above described valve I0 is shifted to direct fluid under pressure from line 69 thru line I2 from which said fluid is distributed to cylinder 2| to efle t a f d g m vem nt of the wheel equal to and thus energizes solenoid to the amount to be removed therefrom in dressing plus the amount of wear on the wheel. Said fluid passes on to cylinders 31 and 40 where pawl 46 effects a feeding movement of the diamond somewhat less in magnitude than theabove mentioned wheel feed movement. Said fluid in cylinder 40 effects a resetting movement of piston 42 and pawl 46. From line I2 fluid. pressure 6 passes thru lineI4, throttle valve I4 and check valve I5 to the head end of piston 29. The flow of fluid thru said check valve is unrestricted so that piston 29 traverses the diamond 3| across H the surface of the grinding wheel at a comparatively high speed. Said high speed may be varied by an adjustable throttle valve I4 in line I4.

During'this traversing movement the cam 63 opens contacts tacts II.

Solenoid 64 is energized when the circuit is I6 and closes a circuit across conclosed thru 'I'I and'thepawl I23 is actuated to rotate disk 61 a predetermined amount. A portion of cam" 65 engages the roller o'fswitch '66 and opens the circuit at this point to deenergize solenoid 68 and relay 18. Deenergizing relay I3 permits" the circuit to the footstock'switch to be closed. Deenergizing solenoid 68 permits shifting of valve II to reverse position whereupon pawl 46 actuated by piston 42 gives the diamond an additional feeding movement while pawl 45 is reset.

Pawl I9 for actuating the wheel feed'is also reset at this time. An unrestricted supply of fluid under pressure is' directed'thru line I3 and 21 to the rodend of piston 29 to traverse the equal to or less than the speed on the first stroke. On .the return stroke of the dressenswitch 52 returns to normal position. The circuit to solenoid 64 is deenergized and the pawl returned to normal position.

Releasing the footstock lever closes switch 63 give; the disk 61 another incremental movement.

Extreme accuracy in size may be maintained by compensating for diamond wear as slight' variation in work size occurs. Assuming that the dressing tool is n'ot'subject' to'wear, the feeding of the wheel to compensate for the reduction in diameter thereof by wear and dressingshould effective tomaintairr a given size of work indeflnitely. I However, because the dressing tool 'is' subject to wear, the flnished size of the work may vary in direct relation to the wear on said tool. Applicant's method of compensating for this wear consists in setting the dressing tool so that thegrinding wheel grinds to the oversize limit when the wheelbase reaches its forward limit of movement. -As the dressing tool wears away the work size will approach the undersize limit. The dressing operationis initiated upon removal of the work from the machine. There-- fore, by gauging the work before removing same from the machine, the operator may determine whether the diamond should be reset andhow much. In-this way, any inaccuracy in work size due to diamond wear may be corrected before the wheel is dressed for another grinding operation.

We claim:

1. In a device of the kind described a'work support, a footstockmounted thereon, a spindle in said footstock, means for operating said spindle, a wheel support, a grinding wheel rotatably mounted thereon, a wheel dressing tool and means responsive to. operation of said spindle operating means for initiating a dressing operation on said wheel.

2. In a device of the kind described, a wheel support having a grinding wheel rotatably mounted thereon, a dressing tool, mechanisms for effecting relative feeding and traversing movements between saiddressing tool and said grinding wheel, means for feeding said wheel thru a distance equal to the amount to be removed by dressing plus the wear on the wheel,

means for feeding said dressing tool thru a part.

of said distance before the traverse movement begins and thru the remainder of said distance before the return stroke of said traverse movement.

3. In a device of the kind described, a wheel support, a grinding wheel mounted thereon, a dressing tool therefor, fluid operated means for effecting a relative traversing movement between said wheel and said dressing tool, a solenoid operated valve for controlling said reciprocating mechanism, a normally closed circuit for energizing said so1enoid,'a second solenoid adapted when energized to open said normally closed circuit, a normally closed circuit .for said second solenoid, a second circuit for said second solenoid, and means responsive to said traversing movement for opening said first circuit and closing said second circuit.

4. In a grinding machine, a work support, a

' spindle mounted therein for rotatably supporting a work piece, a wheel support having a grinding wheel rotatably mounted thereon, means for effecting afeeding movement of said wheel sup-.

port, a dressing tool movable with said wheel support, means for feeding said dressing tool toward said wheel and means for effecting a joint operation of said spindle with said wheel feeding means and said wheel dressing means.

5. A grinding machine having a work carriage and a wheel support, means for rotatably supporting a work piece on said carriage including a footstock, means whereby said footstock may be operated to load and unload work pieces, a wheel dressing device and means actuated upon operation of said footstock for effecting operation of said dressing device.

6. In a device of the kind described, a wheel support having a grinding wheel rotatably mounted thereon, a dressing tool, mechanisms for effecting relative feeding and traversing movements between said dressing tool and said grinding wheel, means for feeding said wheel thru a distance equal to the amount to be removed in said footstock, means for operating said spindle, a wheel support, a grinding wheel rotatably mounted thereon, a wheel dressing tool, means for effecting a traversing movement'of said tool including a reversing mechanism, means for shifting said reversing mechanism, a switch for actuating said shifting means, a ratchet mechanism for operating said switch and means responsive to operation of said spindle operating means for actuating said ratchet mechanism.

8. A device of the kind described comprising a dressing tool, fluid pressure means for effecting a traversing movement of said tool, a valve for reversing said traversing movement, means for shifting said valve, a switch for actuating said shifting means, a ratchet mechanism for operating said switch including a pawl and ratchet and means for actuating same, said actuating means including means for limiting the movement of said ratchet.

9. In a device of the kind described, a work support, a footstock mounted thereon, a spindle in said footstock, means for operating said spindle, a wheel support, a grinding wheel rotatably mounted thereon, a wheel dressing tool, means for effecting a traversing movement of said tool including a reversing mechanism, means for shifting said reversing mechanism, a switch for actuating said shifting means, a ratchet mechanism for operating said switch, means responsive to operation of.said spindle operating means for actuating said ratchet mechanism and means for determining the frequency of operation of said dressing tool.

10. A device of the kind described comprising a dressing tool, fluid pressure means for effecting a traversing movement of said tool, a valve for reversing said traversing movement, means for shifting said valve, a switch for actuating said shifting means, a ratchet mechanism for operating said switch including a pawl and ratchet, means for actuating same, said actuating means including means for limiting the movement of said ratchet and means movable with said ratchet for determining the frequency of operation of said dressing tool.

11. In a machine of the kind described, ,a wheel support having a grinding wheel rotatably mounted thereon, a wheel dressing tool, means for providing a relative reciprocating movement between said dressing tool and said wheel including a motor, means for causing said motor to effect said movement in one direction at a given speed, including athrottle valve set for a comparatively high speed, a reversing mechanism for reversing said -movement, and speed control means operable upon initiation of movement in the opposite direction for changing said speed including a second throttle valve set for a comparatively slow speed, and means for bypassing said second valve during movement of said carriage in one direction.

12. A grinding machine having a grinding wheel, a dressing tool therefor, means for effecting a relative traversing movement between said wheel and said dressing tool, a reversing mechanism for' determining the direction of said traversing movement, means including an electromagnet and means for energizing same for actuating said reversing mechanism to cause said movement in one direction, means responsive to said traverse movement for de-energizing said

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