US2072814A - Grinding machinery - Google Patents

Description

March v2, 1937. l 'F S HAAS 2,072,814

GRINDING MACHINERY Filed Jan. 5, 1934 4 sheets-sheet 1 life@ 7 March 2, 1937.

S. HAAS GRINDING MACHINERY Filed Jan. s, 1954v 4 SheetslSheet 2 n? V y March 2, 1937. F. s. HMS 2,072,814

GRINDING MACHINERY Filed Jan. 5, 1934 4 Sheets-Sheet 3 March 2, 1937. F. s. HAAs 2,072,814

GRINDING MACHINERY File/d Jan. 3, 1934 4 Sheets-Sheel'I 4V Patented Mar. 2, 1937 UNITED STATES A2,072,814 GRINDING MACHINERY Frederick S. Haas, Cincinnati, Ohio, assignor to Cincinnati Grinders Incorporated, Cincinnati, Ohio, a corporation of Ohio Application January 3, 1934, Serial No. '105,106

6 Claims.

Another object of the invention is the pro-v 10 vision of means for supporting the rocker shoes which, due to its construction, reduces the manufacturing costs thereof to an absolute minimum.

A further object of the invention is the simple construction of the bearing members and the co- 15 operating housing, whereby an eiiicient andsturdy product results without excessive production costs and by the use of ordinaryprocessing tools.

Another object of the invention is the pro- 20 vision of improved means for mounting the said bearings so that slight eccentricities are readily compensated for and avoidance of any binding is obtained.

A further object of the invention is the pro- 25 vision of improved means for supplying lubricant to the bearings prior to the rotation of the spindle relative thereto.-

It is also an object of the present invention to automatically effect the rotation of the spindle 30 after the bearings have been properly lubricated and not before.

Other objects and advantages of the present invention should be readily apparent by reference to the following specification, considered in con- 35 junction with the accompanying drawings froming a part thereof and it is to be understood that any modifications may be made in the exact structural details there shown and described, within the scope of the appended claims, With- 40 out departing from or exceeding the spirit of the invention.v

In the drawings: Figure 1 is a front elevation of a grinding machine embodying the improvements of this invention.

Figure 2 is a view, partly in section and partly in elevation,'as seen substantially from line 2-2 on Figure 1.

Figure 3 is a sectional view taken substantially on line 3--3 of Figure 2.

Figure 4 is a sectional view, similar to Figure 3, taken in a plane slightly ahead of the plane of Figure 3 and as seen, for example, on line 4-3 on 55 Figure 2.

Figure 5 is a transverse sectional view taken on line 5-5 on Figure 3.

Figure 6 is a sectional view taken substantially on line 6-6 of Figure 4.

Figure 7 is a sectional view taken on line 1-1 of Figure 3.

Figure 8 is a fragmentary developed view of one of the supporting surfaces as seen on line 8-8 on Figure 5.

Figure 9 is a perspective View f one of the individual bearing shoes.

Figure 10 is a diagram of the electrical circuit involved in the invention.

Figure 11 is a sectional view taken on line I I-I I of Figure 1. l

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

As was noted above, this invention pertains primarily to improved means for supporting, lubricating and rotating spindles of machine tools, such as lathes, grinders and the like. For purposes of illustration, the invention has been shown in the drawings in connection with a grinding machine but it is to be understood that the invention is not limited to that type of machine.

The grinding machine illustrated in the drawings comprises a bed I5, on the upper surface of which is formed ways I6 for guiding a Work supporting table I1 during its movements relative thereto. The table I1 supports atopposite ends a headstock I 8 and tailstock I9 from which respectively project centers 20 and 2l for supporting a work piece 22. Any suitable means may be employed for effecting the reciprocation of the lever 24. The lever 24 operates power reversing mechanism as is usual practice land is under the control of dogs 25 and 26 carried by the table I1.

Projecting rearwardly from the bed I5 is a supplemental bed 21 having formed on the upper surface thereof guide ways 28 for guiding a tool carriage 29 during its movements toward and from the work 22. movements ofthe carriage 29 it carries interiorly thereof a nut 30 in threaded engagement with an adjusting screw 3|. The said screw 3| is table I1, such as the hand wheel 23 and reversing4 In order to effect the said suitably journaled in a. bracket 32 secured to the tion, the bracket encloses suitable actuating mechanism for shaft 34 and adjusting screw 3|, as is well known, which is under the control of handle 36 and ratchet wheel 31.

'I'he tool carriage 29 is provided at opposite ends thereof with supporting bearing portions 38 and 39, one of which, bearing portion 39 for example, is shown in plan in Figure 8. Since the said bearing portions 38 and 39 are identical in construction it is deemed sufcient for illustrative purposes and an understanding of the invention if but one of them be illustrated vand described. The bearing portion 39 has formed thereon a pair of pads 40 and 4| which are each provided with a at or plane surface. The carriage 29 at the ends of the bearing portion 39 is provided with plane surfaces 42 and 43, which as shown in Figure 5, are disposed at an angle to the horizontal. During the machining or processing of the said carriage the surfaces 42 and 431 are planed 0r milled in the usual manner, and during said planing or milling it is only necessary to employ a small face mill or planing tool to face oif the lugs 40 and 4|. From this it will be seen that the bearing supports may be machined with a minimum of expense instead of, as was past practice, resetting the carriage after the faces 42 and 43 were planed in order to bore the carriage and t therein the bearings utilized in the past.

After the bearing pads 40 and 4| have been milled or otherwise suitably faced, small holes or pockets 44 are drilled therein in which are set pins 45. The pins 45 enter a co-operating socket 46 formed in bearing shoes 41 and 48. 'I'he shoes 41 and 48 are similar in all respects and are particularly illustrated in Figure 9 and will be described in detail later.

Mounted on the carriage 29 is a cap 49 having formed therein bearing portions 50 and 5| which are opposite to the carriage bearing portions 38 and 39. Each of the bearing portions 38 and 39 is provided with a plurality of radial bores 52, 53 and 54 into each of which is threaded a screw 55. The inner end of said screws is provided with a at or plane surface 56 which functions as do the pads 40 and 4| for positioning the upper bearing shoes 51, 58 and 59. The bearing shoes 51, 58 and 59, similar to the shoes 41 and 48, are each provided with a socket 46 receiving the tit or pin 60 projecting from each of the screws 55 which prevents the shoes from shifting out of place. -The screws are individually adjustable to determine and effect the proper amount of pressure of their shoes, and after being adjusted are locked in position by suitable clamp or pinch bolts 6|.

Each of the shoes is identical in construction, and as shown in Figure 9, has an arcuate bearing surface 62 which lies adjacent the spindle. As seen in Figure 3, the shoes are of a length substantially equal to the bearing portions 38 :and 39 of the carriage and bearing portions 59 and 5| of the cap. The back4 of the shoes is arcuately shaped as at 63, which arc is substantially concentric with the bearing face 62. At the same time the said back of the shoes is curved lengthwise as illustrated at 64, wherefore the said shoes will contact with the at surface of the beds 40 and 4| or the fiat face of the screws 52 in such a manner as to rock in both directions. It will further be noted that the sockets 46 therein are offset with respect to the longitudinal axis of the shoes, being closer to the trailing edge 65 than the leading edge 66. The purpose for this construcg5 tion will be described in detail later.

Disposed substantiallly centrally of the carriage bearing portions 38 and 39 and cap bearing portions 50 and 5| is aspindle 61 which has journal portions 68 and 69 thereon which are encircled by the said carriage and cap bearing portions and the bearing shoes associated therewith. 'Ihe spindle 61 extends beyond the carriage and cap bearing portions 38 and 5|) and is formed into a tapered nose 10 4to which is secured a grinding wheel flange 1|. The said flange 1| has secured thereto, as by a ring 12, a grinding wheel 13'. Likewise the spindle 61 projects beyond the carriage and cap bearing portions 39 and 5| where it is formed into a tapered nose 14 receiving a pulley or sheave 15. 'I'he sheave 15 is shown in the drawings as of the multiple groove type for the multiple V belts 16. 'I'he said belts 16 are in turn trained about a sheave or pulley 11 secured to a motor shaft 18 of the main drive motor 19.

As will be seen in Figure, the bearing shoes are substantially equally radially spaced about the spindle with two bearing shoes 41 and 48 carried by the carriage and below the parting between the carriage and cap and with three bearing shoes 51, 58 and 59 associated with the cap and above the said parting. 'I'hese shoes are in effect enclosed within chambers formed by the bearing portions 38 and 50 respectively associated with the carriage and cap and by the bearing portions 39 and 5| also respectively associated with the carriage and cap. The chamber 88 formed by the former bearing portions is closed at opposite ends by chamber end plates 8| and 82, while the chamber 83 formed by the latter faces with a plane surface which engages similarl surfaces formed at each end of the lubricant .chambers 80 and 83. Passing through the chamber 80 and through the end plates 8| and 82 thereof are bolts 86 which have a head on one end for engagement with one plate and a nut 81 on the other. Between the nuts 81 and the adjacent plate, and encircling the bolts 86, are springs 88 which yieldably hold the plates to their 'co-operating surfaces on the carriage and cap bearing portions. 'I'he plates 84 and 85 are similarly held against the en d surfaces of carriage and cap bearing portions 39 and 5| by bolts 89 which carry springs 98, similar to the springs 88.

From the foregoing it will be noted that the journal portions 68 and 69 of the spindle 61 are disposed in lubricant chambers through which the lubricant may ow. Due to the smallness of the orifice formed between the chamber end` plates and the spindle journals a certain amount of pressure is necessary to force the lubricant therethrough. At the same time a semi-floating bearing has been provided, since the said chamber end plates are merely yieldably heldin position so that they may shift with the spindle in the event the bearing shoes are positioned slighthousing 9|, in the interior of 'which is formed a lubricant well 92. The lubricant is received and stored in the reservoir chamber 93 formed in the carriage 29 by a transversely extending base or wall 94. The reservoir has formed through the side Wall thereof a port 95 with which is connected one end of a pipe or conduit 98. 'I'he pipe or conduit 96 terminates at the intake of a pump 91 that is fastened to the side wall of the carriage 29 and the said pump has associated therewith a pulley or sheave 98 about which is trained a belt or the like 99. The belt 99 is in turn trained about a pulley |00 formed integral with or secured to the pulley 15 of the spindle 61.

From the other side of the pump 91 is the dis-y charge pipe or conduit |0| which terminates at the intake of a lubricant purifier |02. The other discharge side of the purifier |02 is connected by a pipe or conduit |03 with a supply port'l04 formed in the top cover plate |05 of the carriage cap 49. From the foregoing it will be noted that the tool carriage 29 is self-contained as far as the lubricating system therefor is concerned. The spindle pulley 15, pump 98, purier |02 and the conduits are all suitably enclosed by a guard |06 secured to the side of the carriage 29 and bed extension 21.

Within the lubricant well 92 is a bucket |01 shown in Figures 3 and 6 as formed of a wire mesh through which the lubricant ows into the well proper. This wire mesh bucket |01 is utilized for breaking up any minute air bubbles that may be in the lubricant so that the lubricant actually delivered to the bearings is substantially homogeneous. At one end of the Well 92 the cap 49 is provided with a series of connecting ports |08, |09 and ||0, and at thevother end with a series of connecting ports |08', |09', and |0, the former series terminating in the lubricant chamber 80, While the latter terminates in the lubricant chamber 83. Due to the height of these parts or the entrance thereto above the said chambers a pressure or head is developed on the lubricant which is sufficient to force the lubricant through the orices formed between the chamber end plates and the spindle itself. From this it follows that there will be a continuous ow of lubricant from the well 92 through the series of ports and lubricant chambers from which the lubricant is discharged into the reservoir 93. It should be noted, however, that the ow of lubricant as effected by the pump 98 through the port |04 into the well 92 is materially greater than the outward flow thereof through the series of ports and chambers so that the said Well is at all times lled during the operation of the machine.

In order to apprise the operator of the machine of the lubricant in the lubricant chambers they are each provided with a sight gauge. One of these sight gauges is shown in Figure 11 and comprises a bore |31 communicating at its inner end with the lubricant chamber 80. The outer end of this bore is closed by a glass window |38 held in place by a frame |39 and a gasket |40 between the glass window |38 and carriage wall.`

The maximum level of the lubricant in the well 92 is determined by the stand pipes I I which, as seen in Figure 6, rise to a height above the wire mesh bucket |01. The stand pipes discharge into ports H2, which in turn empty into a discharge pipe |3 which terminates near the bottom of the lubricant reservoir 93. In practice, the pipe ||3 terminates very closely to the base 94 of the well 93 whereby a drop or fall of the lubricant is prohibited and the agitation of the lubricant held to a minimum for holding to a minimum any air bubbles or the like in the lubricant.

The operation of rocking shoe bearings is well understood but it is believed that a short description of this operation would not be amiss at this time. Accordingly, and referring to Figure 5 wherein the spindle is rotating in a counterclockwise direction and assuming that the space between the lead-in edge of the bearing shoe and spindle is provided with operating fluid or lubricant, the operation is as follows:

When the spindle begins to rotate, the lubricating medium is drawn into the lead-in, or is already present at the lead-in, to the bearing by reason of the adhesiveness of the oil to the shaft or spindle. The surface layer of molecules of the oil adjacent thereto is drawn in between the surfaces of the shaft or spindle and bearing shoes. Since the oil or lubricating medium has inter-molecular friction, or what is commonly called viscosity, other molecules of oil are drawn into the bearing space. This causes the spindle journals to lift away from the bearing, and in so doing provides more room for lubricant to enter. After the lubricating medium has entered between the surfaces, the surface layer of molecules adjacent to the spindle is moving with the spindle, while the surface layer adjacent to the bearing is stationary with it. It is obvious, therefore, that all the lubricating medium between these surface layers is in a continual state of slip or what is known as shear. When the surfaces are relatively close to each other the shear forces in the oil are very great and since the stress in a liquid must be the same in all directions a pressure is built up normal to surfaces.

The hydro-dynamic theory is that fluid films show that in order to support a load the pressure change in the volume must be gradual. The theory also proves thatto obtain a gradual change the volume must be wedge shaped with its thickness diminishing in the direction of motion. Equilibrium is reached when the integration of all the pressure elements in the volume is equal to the external load on the spindle. This condition of equilibrium will obtain as long as a copius supply of the lubricating medium is present at the lead-in edge of the shoe. This theory also shows that for optimum conditions the center of pressure occurs nearer to the trailing edge than to the leading edge of the bearing shoe. Therefore, in this invention theI rocking shoes are shown with the supporting edge nearer to the trailing edge.

In the past in order to obtain this condition the rocking shoes were formed with a central rib having an arcuate contact surface which makes it relatively difficult and quite expensive to manufacture or produce. Alternately, the said shoes were formed of irregular shape, that is, with the outer surface of the shoe eccentric to the inner or bearing surface thereof. This type of construction again rendered the shoe difcult to manufacture and required relatively expensive processing operations. By the present construction the inner and outer surfaces of the shoes are substantially concentric with only a slight crown on the said outer surface from end to end. The shoes, however, may be made up in the form of a cylinder and the cylinder then crowned, whereupon the cylinder is divided into segments to provide the individual shoes. From this it will be seen that the construction of the present invention obtains the same beneficial results as the prior constructions but at a cost considerably circuit and stop the said motor a stopping switch under the former manufacturing costs.

Since the lubricant is supplied to the bearing chambers and 83 by gravity the well 92 and the said chambers will be drained if the machine is shut down for any appreciable period of time, such as during the noon hour or over night. It has been found that the greatest damage occurs to the spindle journals and supporting bearings during the interval between the starting of the rotation of the spindle and the supplying of lubricant thereto. In order t-o overcome this difficulty there is incorporated `in the present invention means for supplying a suitable quantity of lubricant to the bearings prior to the starting thereof.

This mechanism comprises a container H4 disposed within the wire mesh bucket |01. The container I |4 has an open top H5 which is: below the upper level of the stand pipes I and will, therefore, receive lubricant by overowing from ythe well 92 as the level thereof rises to and above the said open top H5. The container ||4 is mounted for oscillation in order to dump the lubricant therefrom and for this reason has one end formed with a pocket H6 which is journaled on the nose I I1 of a screw I I8 let through the left hand side wall of the cap 49. The other end of the container ||4 is secured to a shaft H9 journaled in the right hand wall of the cap 49. The shaft H9 extends through and beyond this wall to receive a handle |20 whereby the said shaft and container may be oscillated through for dumping the container. The container is of such cubical content as to contain sufficient lubricant to fill the chambers 80 and 83 and thereby supply a suiicient amount of lubricant to the bearings to last the interval between the starting of rotation of the spindle and the supply of lubricant thereto by the pump 98.

As will be evident, after the lubricant has drained from the system during a shut-down, the chambers, supply ports and sight gauge bore will fill with air which will interfere with the oper-v ation of the bearing shoes if not disposed of. This air will be forced ahead of the lubricant into the sight gauge bore and will naturally collect at the top thereof. In order to dispose of this air the cap 49 is provided with a substantially vertically extending port |4| which empties into a connecting port |42 and said connecting port in turn empties into vertical port |43. The port |43 has its upper end substantially at the top of the lubricant in the well and the air will therefore be dissipated above the lubricant.

In order to insure the dumping of the lubricant from the reservoir container H4 prior to the rotation of the spindle, the spindle motor 19 is rotated or its rotation initiated by the handle |20. The mechanism for accomplishing this comprises a cam or projection |2| integral with or secured to the shaft H9 which operates on one end |22 of a lever |23. The lever |23 is pivoted intermediate its ends at |24 in a chamber |25 formed in the cap 49. The other end |26 of the lever |23 lies adjacent the push button |21 of a starting switch 28. The switch 28 is of the manual type for closing the circuit to effect the operation of the motor switch |29 which includes the magnetic locking switch plate |3I, all as is usual practice. The motor starting magnetic switch |29 and the manual starting switch |28 are connected with the initial power source wires |32 and |33, while the magnetic starting switch is connected by wires |34 and |35 with the motorr'li. In order to break the |36 is also provided.

From the foregoing it will now be evident that the operator with the lever |20 rst discharges the oil or lubricant in the reservoir container I4 to the bearings and then initiates the rotation of the spindle motor for initiating operationof the lubricant circulating pump. From this it is also clear that the spindle bearings are adequately lubricated prior to the rotation of the spindle.

What is claimed is:

1. In a spindle supporting mechanism thel combination of a housing, a spindle associated with the housing and having journal portions thereon, bearing portions formed in the housing to receive the spindle journals, segmental bearing shoes between the housing bearing portions and spindle journals, said shoes having an arcuate bearing portion and'v an arcuate back, plane surfaced pads associated with the housing for contact with the arcuate back of the shoes and having line contact with said shoes whereby they may rock, a cap on the housing and having bearing portions formed therein complementary to the housing bearing portions, screws carried by the cap and projecting into thebearing portions thereof and having a plane inner surface, and segmental shoes each having an arcuate back between the screws and spindle journals and which arcuate backs contact the plane face of the screws whereby said shoes may rock on the plane surface of the screws.

2. In a spindle supporting mechanism the combination of a housing, a spindle associated with the housing and having journal portions thereon, bearing portions formed in the housing to receive the spindle journals, segmental bearing shoes between the housing bearing portions and spindle journals, said shoes having an arcuate bearing portion and an arcuate back, plane surfaced pads associated with the housing for contact with the arcuate back of the shoes and having line contact with said shoes whereby they may rock, a cap on the housing and having bearing portions formed therein complementary to the housing ybearing portions, screws carried by the cap and projecting into the bearing portions thereof and having a plane inner surface, segmental shoes each having an arcuate back bes' tween the screws and spindle journals and which @arcuate backs contact the plane face of the screws whereby said shoes may rock on the plane surface of the screws, and means for holding the shoes against radial displacement with respect to the spindle journals.

3. In a spindle supporting mechanism the combination of a housing and closing cap, a spindle extending through the housing and cap and having formed thereon journal portions, the housing and cap having bearing portions encircling the spindle journals, segmental bearing shoes circumferentially spaced around the spindle journals and disposed between the said spindle journals and housing and cap, plane surfaced supporting members associated with the housing and cap bearing portions on which the arcuate bearing shoes rest and have line contact therewith for rocking purposes relative thereto, plates at each end of the housing and cap bearing portions for forming a chamber within said tion whereby they may shift with the spindle due to the rocking of the shoes.

4. A bearing structureA for a precision grinding machine spindle including a base unit having spaced arcuate bearing receiving recesses formed therein, each of said recesses being provided with inwardly projecting lugs, centering studs carried by said lugs, individual arcuately shaped cap members overlying the respective bearing recesses, a plurality of adjustable abutment screws carried by the cap member, each of said screws having an inwardly extending centering stud, a grinding spindle projecting axially through said bearing recesses and a plurality of segmental bearings disposed in each of said recesses in circumscribing relation to the contained portion of the spindle, each of said segmental bearings having an arcuate inner face shaped to substantially the contour of the periphery of the shaft and having an outer face arcuately curved to fit within the bearing recess, said outer face being provided with a socket for reception of a lug or ad- -justing screw stud and being longitudinally crowned, whereby the studs interengage with the sockets for retaining the bearing members in position for limited oscillation on ther curved outer faces.

5. A bearing structure for a precision grinding machine spindle including a base unit having spaced arcuate bearing receiving recesses formed therein, each of said recesses being provided with inwardly projecting lugs, centering studs carried by said lugs, individual arcuately shaped cap members overlying the respective bearing recesses, a plurality of adjustable abutment screws carried by the cap member, each of said screws having an inwardly extending centering stud, a grinding spindle projectingaxially through said bearing recesses, a plurality of segmental bearings disposed in each of said recesses in circumscribing relation to the contained portion of the spindle, each of said segmental bearings having an arcuate inner face shaped t substantially the contour of the periphery of the shaft and having an outer face arcuately curved to it Within the bearing recess, said outer face being provided with a socket for reception of a lug or adjusting screw stud and being longitudinally crowned, whereby the studs interengage with the sockets for retaining the bearing members in position for limited oscillation on their curved outer faces, said lugs on the base unit definitely determining the position of the segmental bearings carried thereby, and means for securing the adjustable screws in variable relation to the cap whereby the cap segmental bearings are variably urged into positioning engagement with the spindle.

6. A bearing structure for a precision grinding machine spindle including a base unit having spaced arcuate bearing receiving recesses formed therein, each of said recesses being provided with inwardly projecting lugs, centering studs carried by said lugs, individual arcuately shaped cap members overlying the respective bearing recesses, a plurality of adjustable abutment screws carried by the cap member, each of said screws having an inwardly extending centering stud, a grinding spindle projecting axially through said bearing recesses, a plurality of segmental bearings disposed in each of said recesses in circumscribing relation to the contained portion of the spindle. each of said segmental bearings having an arcuate inner face shaped to substantially thev contour of the periphery of the shaft and having an outer face arcuately curved to fit within the bearing recess, said outer face being provided with a socket for reception of a lug or adjusting screw stud and being longitudinally crowned, whereby the studs interengage with the sockets for retaining the bearing members in position for limited oscillation on their curved outer faces, washer-like plates mounted on the spindle at opposite sides of the bearing areas and overlying the faces of the unit and cap at the bearings, and means for yieldingly urging these plates, one toward another into intertting engagement with respective faces of said parts, whereby said plates are free to float with the shaft and form an oil seal against escape of lubricant axially of the bearings.

FREDERICK S. HAAS.

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