US1976125A - Grinding machine - Google Patents

Description

Oct. 9, 1934. s HAAS 1,976,125

GRINDING MACHINE Filed May 12, 1952 3 Sheets-Sheet l F. s. HAAS GRINDING MACHINE Filed May 12, 1952 3 Sheets-Sheet 2 Oct. 9, 1934. F. s. HAAS 1,976,125

GRINDING MACHINE Filed May 12, 1932 3 Sheets-Sheet 5 Patented Oct. 9, 1934 UNITED STATES PATENT OFFICE Application May 12, 1932, SerialNo. 610,838

9 Claims.

This invention relates to improvements in machine tools and especially to improvements in grinding machines.

In the operation of grinding machines, particularly center type grinders, the grinding wheel is fed toward the center of the work at predetermined increments to bring the work to the desired size. In the grinding of work pieces of a length greater than the width of the grinding Wheel either the work or the grinding wheel is axially traversed relative to the other to reduce the work throughout its entire length. Upon reduction of the work to the desired size it is necessary to retractthe grinding wheel a given amount to permit the withdrawal of the work from the machine. This retraction of the grinding wheel must be sufficient not only to clear the work within the machine, but also to clear the stock on the work about to be introduced in the machine. In the past, accidents have occurred due to the operator not retracting the grinding wheel a suficient amount to clear the extra stock on the work that is to be removed by grinding.

It is therefore one of the principal objects of the present invention to provide automatic means which insures the necessary retraction of the grinding wheel to clear successive unground or rough work pieces.

Another object of the invention is the provision of improved semi-automatic feeding mechanism for actuating the grinding wheel and its support relative to the bed.

A further object of the invention is the provision of improved hydraulic mechanism supplementing the normal automatic feed mechanism for actuating the grinding wheel and its support relative to the bed of the grinder together with improved means for controlling the hydraulic feed mechanism.

Other objects and advantages of the present invention should be readily apparent by reference to the following specification considered in conjunction with the accompanying drawings,

forming a part thereof, and it is to be understood the machine shown in Figure 1 as seen particularly from line 2-2 thereon.

Figure 3 is an enlarged elevational view of the cross 'feed operating mechanism.

Figure 4 is a fragmentary sectional view on line 4-4 of Figure 3.

Figure 5 is a sectional view taken on line 5-5 of Figure 4.

Figure 6 is an enlarged sectional detail view of the valve returning mechanisms as seen from line 6-6 on Figure 4.

Figure '7 is a diagrammatic view illustrating the hydraulic circuits involved in this invention.

Throughout the several views of the drawings similar reference characters have been employed to denote the same or similar parts.

While the invention is illustrated in the drawings and will be'described in connection with a center type grinder, it is to be understood that it has equal application to any machine tool requiring a relative separation between the tool thereof and the work being operated upon. Accordingly, the machine comprises a bed 10 having formed on the upper end thereof guideways 11 for supporting during its movement relative to the bed a work supporting table 12. The table 12 has mounted thereon the usual head stock 13 and tail stock 14 supporting between appropriate centers a work piece which is to be operated upon by the grinding wheel 15. Any suitable or desirable means may be employed for translating the table relative to the bed which means are adapted to be reversed at each end of the reciprocal stroke thereof. For effecting the reverse of the table, the usual reverse lever 16 is employed, being pivoted at 17 intermediate its ends to the forward face of the bed, as shown in Figure 1. The table 12 has adjustably secured to its face reversing dogs 18 and 19 adapted to respectively engage with the upper end of the lever 16 for eflecting its reverse oscillation.

The grinding wheel 15 is secured to one end of the spindle 20 journaled in suitable bearings 21 mounted in a slide or carriage 22. The carriage 22 is received in guideways 23 formed in the upper surface of a bed extension 24 which projects from the rear surfaces of the bed 10. Depending interiorly of the bed extension 24, from the carriage 22, is an arm or lug 25 in which is pirmed or otherwise secured a nut 26 in threaded engagement with a cross feed or adjusting screw 27. As shown in Figure 2, the nut 26 has formed integral therewith or secured thereto a sleeve 28 forming a guard for the threaded portion of the screw 27 to prevent dirt, grit or the like from settling on said threads.

The screw 27 projects through the bed to the forward face thereof where it is provided with a splined portion 29 received in a similarly splined or keywayed bearing sleeve 30 of a gear 31. The gear 31 meshes with a pinion 32 integral with a stud 33 journaled in a hub 34 of a ratchet gear or wheel 35. The hub 34 is keyed to the stud 33 whereby the wheel 35 and stud 33 turn as a unit and the said hub 34 is journaled on anti-friction bearings 36 supported by a cover plate 37. The plate 37 is secured in any desirable manner to the forward open end of a casing or housing 38 secured to the forward face of the bed and which housing encloses the gear 31 and pinion 32. The ratchet wheel 35 has rotatably mounted thereon, as by a pin 39, spur gear 40 meshing with internal gear teeth 41 cut on the inside periphery of the ratchet wheel 35. The gear 40 meshes at a point diametrically opposite the point of mesh with the gear 41 with a spur pinion 42 integral with a micrometer or hand wheel 43 loosely journaled on a reduced portion of the stud 33. Lock nuts 44 on the end of the stud 33 secure the parts to one another. The micrometer or hand wheel 43 has mounted in it a spring pressed plunger 45 including the knob or handle 46 and a pin 47 adapted to enter any one of a plurality of perforations or sockets 48 formed in the ratchet wheel 35 slightly inside the ratchet teeth 49 formed around the periphery thereof.

With the spring pressed plunger 45 interengaged with one of the perforations or sockets 48 the micrometer or hand wheel 43 and ratchet wheel 35 are rotated as a unit for rotating the pinion 32 and the gear 31 which rotates the screw 27 at a rate determined by the ratio between the pinion 32 and gear 31, which is comparatively high. In order, however, to actuate the grinding wheel at a very slow feed, for example a fractional thousandth part of an inch, the knob 46 is drawn outwardly to withdraw the plunger 47 from the socket 48 whereupon it is actuated a distance between one or more of the sockets 48, which rotates the pinion 42 and planetary gear 40 for thereby rotating the ratchet wheel 35 at a very slow rate of speed. From the foregoing it will be noted that the grinding wheel and its carriage may be actuated at a comparatively slow or a fast rate of speed through the wheel 43.

In order to feed the grinding wheel toward the work, as for example at each end of the travel of the carriage 12, the ratchet wheel 35 has engaged therewith a pawl 50 pivotally mounted at 51 on the end of a rod 52, see Figure 1. A spring 53 has one end secured to the pawl 50 and the other end to the rod 52 for at all times tending to pull the pawl 50 toward the ratchet teeth 49. The rod 52 has secured to its other end a piston 54 contained within a cylinder 55 shown in elevation in Figure 1 and diagrammatically in Figure 7. The cylinder 55 has extending from its opposite ends conduits or pipes 56 and 5'7 respectively terminating in a valve sleeve 58 carried by a bracket 59 secured in any desirable manner to the forward face of the bed 10. Enclosed within the sleeve 58 is a. spool type valve 60 abutting o' its lower end with one end'of a spring 61 which is in turn butted against a closure plug or cap 62 for normally holding the valve 60 in the elevated position as shown in Figure 7. The valve 60 has extending from it a stem 63 bearing at its upper end an anti-friction roller 64 adapted to engage cam faces 65 and 66 formed on the lower end of the reversing lever 16.

Terminating at the valve sleeve 58 is one end of conduits or pipes 67, 68 and 69 of which conduit 68 is the pressure line while conduits 67 and 69 are branch exhaust or return lines. The branch conduit 68 terminates in a conduit or pipe 70 into which the pump 71 discharges an hydraulic medium such as oil which was drawn through suction pipe 72 from a. tank or "mp 73.

It is to be understood that the piston 54 moves to the right for causing the pawl 50 to rotate the ratchet wheel 35 in a counterclockwise direction, as seen in the drawings, for feeding the grinding wheel toward the work. It is also to be understood that the pawl 50 must be retracted after each feeding stroke preparatory to the next infeed of the wheel. In order to feed the wheel toward the work at each reversal of the table 12, the reversing lever 16 is provided with the cam faces 65 and 66 which are so disposed to the valve stem 63 that upon oscillation of the lever in either direction one or the other of the cam faces will engage with the roller 64 to depress the valve 60 for momentarily reversing the flow of fluid through the conduits 56 and 57 for ultimately changing the direction of reciprocation of the piston 54. In order to prevent excessive pressure in the system as when the piston 54 is at one end of its stroke or when the ratchet wheel 35 is held against rotative movement as when the work is tothe final size, the branch pressure conduit 68 has connected therewith a relief valve 74 which discharges through a pipe 75 to the tank or sump.

In order to reverse the direction of actuatio of the ratchet wheel, as through the handle 46, the pawl 50 must be; free of the ratchet teeth. 11! For this purpose the' cylinder '55 has projecting from its end, through which the piston rod 52 passes, a pin or bar 110 having its outer end 111 tapered or cam shaped to ride on the adjacent face of the pawl 50 and thereby hold the pawl out of contact with the ratchet teeth. It is to be understood that the piston 54, rod 52 and pawl 50 are always retracted to the same point so that when in the retracted position the bar 110 engages the pawl as above described.

The grinding wheel and its carriage are adapted to be actuated at a rapid rate during a portion of the stroke as when retracting the grinding wheel at the conclusion of the grinding operation and when advancing the said wheel from a point remote from the work to a point adjacent the same. For this reason, the screw 27 has secured to it intermediate its ends a piston 76 that is enclosed in a cylinder 77 closed at opposite ends as by means of cylinder heads 78 and 79. The head 79 is secured to an extending sleeve-like portion 80 formed integral with the housing 38 and projecting interiorly of the bed 10. The cylinder heads 78 and 79 each carry suitable packing to prevent the escape of hydraulic pressure from the cylinder 77 around the screw 27 where it through them. The heads 78 and 79 are further respectively formed with ports 81 and 82 respectively in communication with pipes or conduits 83 and 84, which in turn terminate adjacent the valve casing 85, see Figures 4 and 5. Y

The casing 85 encloses a rotary plug type valve 86 which is adapted to be oscillated for alternately connecting the conduits as and 84 with the pressure line 70 and exhaust line 87 into which the branch exhaust lines 67 and 69 empty. The rotary plug valve 86 has its opposite sides cut away to form ports or passages 88 and 89 shown in Figure 5 and with'which passages the conduits 88 and 84 are alternately connected. The pressure conduit 70 terminates, as shown in Figure 4, in the valve casing in alignment with a longitudinal port 90 formed therein, which in turn connects with a transverse port 91 formed in the casing 85 which empties into the passage 88. The discharge conduit 87 terminates in the casing 85 at a. point in substantial alignment with the axial center of the plug valve 86 where the said'valve is provided with an opening 92 which terminates in a radial port 93 emptying into the passage 89.

From the foregoing it will be seen that with the plug 86 in the position shown in Figure 7,

the hydraulic medium in conduit 70 is connected by means or" apassageway 88 with the conduit 83 for actuating the piston 76 to the left discharging the medium ahead of it through the conduit 84, passage 89 and return conduit 87. This will actuate the grinding wheel carriage 22 and grinding wheel 15 to the left as seen in Figure 2 or toward the axial center of the work.

In order to rotate or oscillate the valve 86, it is provided on its forward end with a reduced stud portion 94 which projects through and beyond the cover 37 of the housing 38. Secured to the stud 94 exteriorly of the cover 37 is alatch lever 95 having the shape substantially illustrated in Figure 3. The lever 95 is provided with a finger piece 96 and a latch or stop portion 97 at one end and a stop portion 98 on its side opposite to the latch 97. The valve plug 86 is provided near the stud 94 with a groove 99 in which is positioned the hook end 160 of a spring 101. The hook end 100 of the spring encircling a pin 102 carried by the plug 86, while the other end 193 of the spring 101 is similarly hooked about a pin 19% projecting from the housing 38. The spring 191, as seen in Figures Band 6, oscillates the valve plug 86 in a clockwise direction and maintains the latch lever 95 in contact with a stop pin 105 projecting from the forward face of the cover plate 37. With the latch lever 95 in the position shown the plug valve 86 is positioned, as shown in Figure 7, for connecting the hydraulic medium with the right hand end of the cylinder 77 and actuating the grinding wheel to the left or toward the work. This causes, as was above described, the grinding wheel to be fed toward the work a distance determined by the head 79'whereupon the pick feed of the grinding wheel is thrown in for feeding the grinding wheel toward the work in small increments as is the usual practice at each end of the reciprocatory stroke of the work table as above described. This feed continues until a pin 106 projecting from the rear of the ratchet 85 engages. with the stop portion 98 of the latch lever 95. At this time the work should be to the desired exact size so that successive work pieces are reduced correspondingly. In the event, however, due to wear of the grinding wheel, the work is slightly oversize, the spring pressed'plunger .5 is withdrawn from one of the sockets 48 and advanced in the desired direction for retracting the pin 106 from the stop. This retraction of the ratchet wheel 35 does not in any wise affect the position of the grinding wheel, so that as soon as the plunger has been moved a sufiicient distance one or more of the sockets 48, it is re- This movement of the handle 46 is continued through substantially a complete revolution of the ratchet wheel or until the pin 106 engages with the latch lever 95 on its under surface for actuating it in a counter-clockwise direction, as seen in Figure 3. This movement of the latchlever 95 raises it from the stop pin 105 causing the ratchet pin 106 to ride along the under surface of the said latch lever into en-- gagement with the latch 97. When the pin 106 engages the latch 9'7 the lever is in the position indicated in dotted lines in Figure 3, thereby connecting the hydraulic medium in the line 70 with the conduit or pipe 84 for actuating the piston 76 to the right and retracting the grinding wheel from the work. As was noted above, this actuation of the latch lever 95 takes place only after a susbtantially complete revolution of the ratchet wheel in a grinding wheel retracting direction thereby insuring suificient clearance between the work center and wheel for the next rough or unfinished work piece.

After the said unfinished work piece is mounted between the head and tail stocks the handle 46 is again grasped for actuating the ratchet wheel in a direction to feed the grinding wheel toward the work. As soon as this wheel is rotated in a feeding direction the pin 106 carried thereby leaves the latch 97 of the latch lever 95 so that its spring 101 may immediately rotate the valve plug 86 to connect the hydraulic pressure with the conduit or line 88 for again feeding the grinding wheel at a rapid rate toward the work. This rapid feeding of the work takes place during the first movement of the ratchet wheel 35 in a feeding direction so that the clearance between the Work is immediately taken up, leaving practically only the necessary slow feeding movement of the grinding wheel as represented by the stock on the work to be removed.

What is claimed is: c

1. In a grinding machine of the class describedthe combination of a bed, a work supporting table mounted on the bed; a grinding wheel support mounted on the bed for movement relative thereto toward and from the work supporting table, an adjusting screw having'an ation by the spring means except when actuated to operate the screw a irection to move the carriage toward the work supporting table.

2. In a grinding machine of the class described the combination of a bed, awork supporting table mounted on the bed, a grinding wheel support mounted on the bed for movement relative thereto toward and from the work supporting table, an adjusting screw having an operative threaded connection with the carriage, a hand wheel for rotating the screw, a piston secured to the screw for effecting axial movement thereof and thereby adjusting the carriage, a valve for connecting an hydraulic medium with opposite sides of the piston, spring means for actuating the valve in one direction,

and mechanical means carried by the hand wheel for holding the valve against actuation by the spring means except when actuated to operate the screw in a direction to move the carriage toward the work supporting table, said means comprising a pin carried by the hand wheel adapted to shift the valve against the spring means when the hand wheel is actuated in a direction to move the carriage away from the work supporting table.

3. In a grinding machine of the class described the combination of a bed, a grinding wheel carriage mounted thereon for movement relative thereto, a bracket mounted on the forward face of the bed, feed means supported by the bracket and including a, hand wheel, a transmission train actuated by the hand wheel, an adjusting screw having one end slidably connected with the transmission train and the other end in threaded engagement with the carriage, a cylinder car ried by the bracket, a piston within the cylinder secured to the screw, a valve carried by the bracket for connecting an hydraulic medium with opposite sides of the piston, and co-operating means carried by the valve and hand wheel for controlling and effecting the operation of the valve in accordance with the operation of the hand wheel.

4. In a grinding machine of the class described the combination of a bed, a grinding wheel carriage mounted thereon for movement relative thereto, a bracket mounted on the forward face of the bed, feed means supported by the bracket and including a hand wheel, a transmission train actuated by the hand wheel, an adjusting screw having one end slidably connected with the transmission train and the other end in threaded engagement with the carriage, a cylinder carried by the bracket, a piston within the cylinder secured to the screw, a valve car-- ried by the bracket for connecting an hydraulic medium with opposite sides of the piston, a latch lever on said valve, an abutment carried by the hand wheel for engaging said latch lever when operated in one direction for limiting the rotative movement of the screw and engaging said latch lever when rotated in the other direction for actuating said valve.

5. In a grinding machine of the class described the combination of a bed, a grinding wheel carriage mounted thereon for movement relative thereto, a bracket mounted on the forward face of the bed, feed means supported by the bracket and including a hand wheel, a transmission train actuated by the hand wheel, an adjusting screw having one end slidably supported by the transmission train and the other end in threaded engagement with the carriage, a cylinder carried by the bracket, a piston within the cylinder secured to the screw, a valve carried by the bracket for connecting an hydraulic medium with opposite sides of the piston, a latch lever on said valve, an abutment carried by the hand wheel for engaging said latch lever when operated in one direction for limiting the rotative movement of the screw and engaging said latch lever when rotated in the other direction for actuating said valve, and yielding means for actuating said valve in the other direction.

6. In a cross feed mechanism for grinding machines or the like the combination with a bed, and a grinding wheel supported thereby, of across feed screw having a threaded operative connection with the grinding wheel, a piston on the screw intermediate its'ends, a cylinder enclosing the piston, an hydraulic source of pressure, an oscillatable valve adapted to be alternatelyreversely oscillated for alternately connecting the pressure to opposite ends of the piston, means actuable through a given range for effecting the alternate oscillation of the valve at one end of its range of movement, and yielding means associated with the valve and co-operating with the last named means to insure the operation of the valve.

7. In a cross feed mechanism for grinding machines and the like the combination with a bed, and a grinding wheel supported thereby for movement relative thereto, of a cross feed screw adapted to be rotated and axially shifted for actuating the grinding wheel at slow and fast speeds relative to the bed, means operatively connected to the screw and actuable through a given range for imparting a given movement to the grinding wheel, a piston connected with the screw for effecting its axial movement, an hydraulic pressure source for actuating said piston, a valve for alternately connecting the pressure with opposite sides of the piston, a valve actuator associated with the valve, and means carried by the screw rotating means operable at one end of its range of movement for engagement with the valve actuator to operate same and engageable with the valve actuator when at the other end of its range for limiting the rotative movement to be imparted to the screw.

8. In a cross feed mechanism for grinding machines and the like the combination with a bed, and-a grinding wheel supported thereby for Y movement relative thereto, of a cross feed screw adapted tobe rotated and axially shifted for actuating the grinding wheel at slow and fast speeds relative to the bed, means operatively connected to the screw and actuable through a given range for imparting a given 'movement to the grinding wheel, a piston connected with the screw for effecting its axial movement, an hydraulic pressure source for actuating said piston, a valve for alternately connecting the pres sure with opposite sides of the piston, a valve actuator associated with the valve, means carried by the screw rotating means operable at one end of its range of movement for engagement with the valve actuator to operate same and engageable with the valve actuator when at the other end of its range for limiting the rotative movement to be imparted to the screw, and yielding means for operating the valve in its other direction.

9. In a cross feed mechanism for grinding machines and the like the combination with a bed, and a grinding wheel supported thereby for movement relative thereto, of a cross feed screw adapted to be rotated and axially shifted for actuating the grinding wheel at slow and fast speeds relative to the bed, means operatively connected to the screw and actuable through a given range for imparting a given movement to the grinding wheel, a piston connected with the with the valve actuator when at the other end of its range for limiting the rotative movement to be imparted to the screw, yielding means for operating the valve in its other direction, and means associated with the valve actuator where-' by the valve may be manually adjusted.

FREDERICK S. HAAS.

Images