US2881569A - Grinding machine - Google Patents

Description

April 14, 1959l ".1. J. sTRNAD ET AL 2,881,569

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fmw u g" JNVENTRS i JAMES smv/m i Qj HARRY B. l/A/vKAa/rEN nited States Patent 2,881,569 GRINDING MACHNE James I. Strnad, Shaker Heights, and Harry B. Van Auken, Brooklyn Heights, Ohio, assignors to Lempco Products, Inc., Bedford, Ohio, a corporation of h10 Application October 24, 1955, Serial No. 542,333

s claims. (ci. 51s6) This invention relates to a grinding machine and, particularly, to a grinding machine of the kind in which a subassembly comprising the grinding wheel, the means for mounting it, and the motor by which it is driven is caused to reciprocate immediately above the work.

A commercially successful grinding machine of that type is illustrated in the prior application of James J. Strnad, led July 12, 1951 under Serial No. 236,323, now vPatent No. 2,738,625, dated March 20, 1956. `In grinding machines of the kind therein shown, the work is mounted on a moveable work table supported on trunnions, being brought into and out of contact with the grinding wheel by moving the entire work table up or down by means of a second electric motor mounted on the frame of the machine. The grinding wheel assembly, work motor included, is reciprocated by the second motor. This arrangement permits of the use of a relatively simple grinding wheel assembly but makes for a machine which, although admittedly uncommonly versatile, tends to be somewhat expensive when considered from the standpoint of small machine shops, neighborhood garages, and automobile service stations doing surface grinding.

The present invention dispenses with the complexities introduced by the moveable work table, substituting for it fixed work-mounting rails carriedby the supporting structure on which rails'the work'is located by means4 of jack screws or otherwise," as'may be'preferred. To

provide needed relative movement in a vertical direction between the grinding wheel and the work, manually operable adjusting means are provided in proximity to the grinding wheel assembly. Together with the adjusting means, the grinding wheel assembly is incorporated in a reciprocable carriage on which the motor for reciprocating the carriage is itself mounted. On the carriage are provided means for carrying much of the weight of the grindingwheel assembly, such means being so arranged as to make it at least as easy to move the grinding wheel assembly upward in opposition to the force of gravity as downward. A variety of novel features of lesser importance also* are provided.

Thus the objects of the invention may be said to be, in the main, to simplify construction, reduce cost, and introduce features adding new convenience in and to grinding'rnachines of the overhead type.

Other objects, advantages and characteristics of the invention will be apparent from the description which follows and from the accompanying drawings, in which:

Figure 1 is a' front elevation of the grinding machine of the present invention;

Figure 2 is a corresponding end elevation seen as if from line 2-2 of Figure 1;

Figure 3 is a top plan of the carriage seen as if from line 3--3 of Figure 2 showing the superstructure by which the work motor is mounted in the carriage, the scale being approximately twice that of Figures 1 and 2;

Figure 4 is a section with parts in elevation on line 2,881,569 Patented Apr. 14, 1959 ICC 4f4 of Figure 3, the scale being approximately three line Figure 7;

Figures 9 and 10 are fragmentary sections on lines 9--9 and 10-10 of Figure 3; and

Figure 11 is a detail showing the ball-and-socket joint used at the lower ends of the pressure cylinders.

The grinding machine as a whole, seen in Figure 1, includes a base 1, such base constituting the primary supporting structure for the machine. It consists, among other things, of a plurality of spaced uprights 2 and a plurality of spaced uprights 3. The former are on the front side of the machine, seen in Figure 1. The latter (one of which is seen in Figure 2) are on the back side. Mounted on uprights 2 is a horizontal channel 4 having outward-1y directed iianges 4a and 4b; similarly lmounted on uprights 3 is a horizontal channel 5 having "outwardly directed flanges 5a and 5b. Welded to flanges 4a and 5a, respectively, are a narrow track or runner 6 and awide track or runner 7. Fastened to the latter by bolts 9 is a rack 8, such rack being shown in detail in Figures 9 and l0. Rack 8 meshes with a rotatable pinion 10 driven as hereinafter explained from an overlying carriage that is adapted to move longitudinally of the machine as a Whole.

Carriage 11, which spans the space between the two runners, is formed with a square, rather shallow base 12 of generally box-like construction (Figure 3). Mounted onfbase 12 is a superstructure carrying the traversing motor for the carriage, the work motor, vthe grinding wheel, and a number of other parts which will be described below. This superstructure, bestseen in Figure 1 6, consists for the most part of a secondary supporting ylow, hollow 22a being indicated in dotted lines.

-gular buttresses 14 (Figures 3 and 6).

structure 13 formed integrally with base 12 at the front of the carriage; i.e., the left-hand side of the carriage as seen in Figure 6. Secondary supporting structure 13 includes and is `flanked by two integrally formed trian- Separately mounted on base 12 and thus forming another part of the superstructure is a tertiary 'supporting structure 15,

likewise best seen in Figure 6, which incorporates and is `flanked by a pair of closely spaced triangular 4buttresses l 16 (Figure 3).

Forming part of tertiary supporting structure 15 is a ring-shaped supporting piece 17 for traversing motor 18. The latter has at its lower end an extension 18a containing a series ofv reduction gears vll `and-at its upper end a y wheel 19. An attached gear #tbox 20 contains additional gearing and thel shaft 20a for mounting and driving pinion 10 (Figure 10).

Work motor 21, omitted from Figure 6 in the interestsv of clarity, is seen to best advantage in Figure 4. It is largely conventional except that shaft 22 thereof is hol- 'At its lower end shaft 22 is provided `with an externally threaded extension 22b that serves as the spindle of the grinding wheel. Work motor 21 is supported from a supporting l vring 23. To supporting ring 23 are welded two vertically 4extending angle pieces 24 (Figure 5).

3 ondary' supporting struct-urel 13. Slide ends 26 are tapered as shown in Figure and are adapted to move up and down in ways of corresponding shape that are formed in adjoining portions 28.

Extendingthrough work motor 21 from one end thereof to the other are threaded tie rods 30, best seen in Fig-urey 4. To the lower ends of tie rods 30 is fastened a two-piece splash shield 31 of telescopic construction that is similar to the splash shield shown and described in the above-mentioned prior application. Like the latter, it includes a iexible skirt 31a. Carriage base 12 is formed with an opening 32rwhich in the embodiment of the invention shown in the `drawings is large enough to accommodate splash shield 31: see Figure 5. Opening 32 has at one point an extension 32a of a size and shape such as to permit it to accommodate junction box 33 on work motor 21 (Figure 2 and 3). A conventional grinding wheel 34, best seen in Figure 4, is supported from an annular mounting piece 35 that is held in place on shaft extension 22b by means of a nut-like annulus 36. v

In addition to serving as the nut holding mounting piece 35 in position, annulus 36 carries a depending deector 37. The latter causes a spreading and constant spraying onto the interior surfaces of grinding wheel 34 of a liquid coolant that is admitted through hollow 22a in motor shaft 22. Annulus 36 is threaded onto an externally threaded portion 38 at the lower end of shaft extension 22b. It is evident that, if desired, extension 22b may take the form of a separate element attached in suitable fashion to shaft 22. It is for these reasons and in this sense that shaft extension 22b can be regarded as. the spindle from which the grinding wheel is supported.

At the top 'of shaft 22 is a fixed fitting 39 of more or less conventional construction the lower end of which projects into the hollow 22a. in the shaft. At its upper end, fitting 39 is coupled to a liexible hose 40 for supplying coolant (Figures l and 2). lThe telescopic connection between fitting 39 and shaft 22 is such that the latter may rotate freely about the fixed lower end of fitting 39 without permitting coolant to escape. Coolant is fed into hose 40 by' means of a coolant pump 41 located as shown in Figure 2. It is driven by a pump motor 42 carried by anP annular supporting piece 43. On its intake side, :pump 41r communicates with a coolant reservoir 44 disposed between uprights 2 and 3 in primary supporting structure 1. A-drain plug 45 (Figure 2) 'is provided near the low end of reservoir 44 to permit spent coolant to be removed.

In passing, it should be noted that the electrical controls for traversing motor 18, work motor 21 and pump motor 42, -all of which are connected to the upright conduit box 46 shown in Figure 2, are located on a control panel 47 on the front face of carriage 11. Forming part of thefvariou's controls on control panel 47 are a plurality of Ypush buttons 48 and an actuating lever 49, the latter being provided for easy control of work motor 21. Control .panel 47 and conduit box 46 are interconnected through `conduit 50 (Figures 2 and 3).

As has already been brought out, work motor 21 and grindingwheel 34 are supported on -a vertically moveable slide in secondary `supporting structure 13. Slide ends 26,l which are machined to close tolerances, may conven'iently be welded to the plate 51, shown in vertical cross 'section 'in Figure 4 and in horizontal cross lsection in Figure 5. Welded to plate 51 on the front face thereof is a'paer 152,' likewise-seen in section in Figures 4 and 5. A nut 53 formed as "shown in Figure 5 is attached to plate 51 by -rheans of bolts54: these bolts, the ends of which areth'readed in'to the body 'of nut 53, pass through openings in spacer 52. Nut 53 is internally tapped t'o accommodate a screw shaft 55 that extends vertically within secondary supporting structure 13: see Figure 4.

By rotating screw shaft 55, the sub-assembly comprised of nut 53, spacer 52, plate 51 and slide ends 26 may be caused to move up or down to any one of a wide variety of different positions and, having arrived there, to remain in the selected position after rotation of screw shaft 55 ceases. Work motor 21 moves with the slide, causing grinding wheel 34 to move down or up toward or from the work (not shown). The latter is held in place on rails located in the space between channels 4 and 5. The means by which screw shaft is rotated to bring about movement of the sub-assembly will next be described.

Screw shaft 55, at its lower end, has an accurately machined portion 56 of reduced diameter. A ball bearing assembly 57 toward the top of reduced portion 56 and a tapered roller bearing assembly 58 toward the bottom of reduced portion 56 locate the lower end of screw shaft 55 in place, such bearing assemblies being mounted as shown in Figure 4 in secondary supporting structure 13. A cap-like closure 59 directly below the lower end of screw shaft 55 seals olf bearing assembly 58.

Mounted on reduced portion 56 of screw shaft 55 is a bevel gear 60 which meshes with a bevel gear 61 on a horizontally extending shaft 62 supported as shown within a tubular mounting piece 63. The latter is held in place by bolts (not shown) on a forwardly projecting portion 64 forming part of secondary supporting structure 13. At the outer end of shaft 62 is a hand wheel 65 provided with a snap-in disk 66. The latter acts as a closure for a chamber 65a in hand wheel 65y in which is located the retaining nut 62a disposed at the outer end of shaft 62.

The upper end of screw shaft 55 is formed as shown in Figure 4 with a stepped portion 67. A roller bearingv assembly 68 mounted in secondary supporting structure 13 locates stepped portion 67 in position. Above bearing assembly 68 is a frusto-conical indexing element 69: the latter may be selectively positioned zeroed re1- by moving work motor 21 and grinding wheel 34 towardy or from the work, the magnitude of the vertical movement of the grinding wheel can be read off on scale 70,`

which preferably is graduated in divisions of 000 of an inch each.

The means so far` described for supporting the grinding wheel assembly are located along the front edge of base 12 of carriage 11: see Figure 6. The weight of the work motor, the means for mounting the grinding wheel, and the grinding wheel itself, taken with supporting ring 23 and the lesser elements which connect ring 23 to the slide, is such as to develop a turning moment of considerable magnitude. In theory, at least, it is capable of affecting the alignment of the parts and the accuracy of the machine as a whole. In order to overcome the effect of this turning moment, it is desirable (although not always necessary) to incorporate in carriage 11 auxiliaiy means for supporting the grinding wheel assembly.

To this end, a cross bar 72 is attached to the grinding wheel assembly at or below the level of coupling 39. By means of two internally threaded sleeves 73 (Figure l), cross bar 72 is coupled to tie rods 30 where the latter project through the end bell at the upper end of work motor 21. Sleeves 73 are threaded directly onto the threaded ends of tie rods 30. Bolts 74 passing through openings in cross bar 72 are threaded into, the sleeves. A nut 75 (Figure 4) prevents fitting 39 from moving relatively to cross bar 72. Thus cross bar 72 and fitting 39 lare rigidly connected to work motor A21 and move with it as the grinding wheel assembly is l moved up or down by rotation of hand wheel 65.

As appears from Figures l and 2, cross 'bar 72 is piston rods 77 projecting vwout of the upper ends of two pressure cylinders 78. In the interestsofease ofalignment, the latter are constructed as shown in `Figure 1l ink such manner that their lower ends seat. on carriage base 12 on shallow seats of the ball-andfsocket type. To operate the pistons, a suitable pressure uid, which may be compressed air at -a gage pressure of about 50 pounds, is'supplied through a line 79 (Figure 2) incorporating'an air pressure regulator 80 and a pressure relief valve 81. Line 79, which is connected to the cylinders below the pistons in the cylinders,yis connected at its remote end to a source of compressed air. Thus the pressure fluid, operating against the lower faces of the pistons, is enabled to exert a force tending to move the pistons, piston rods,- cross' bar and grinding wheel assembly to an elevated position in relation to carriage base 12. l l

In this manner, the entire grinding* wheel assembly s resiliently-supported from carriage base 12. Such support is supplied in two opposed zones, although there is no reason why a jsingle cylinder located diametrically opposite screw shaft 55 or several such cylinders in several widely spacedzones may notbe used if desired. In addition to carrying theweight of the grinding wheel assembly including work motor 21, mounting means 35 and grinding wheel 34, this arrangement eliminates back lash in screw shaft 55 and those parts that are coupled to screw shaft 55. This it does by urging nut 53 upward against the lower faces of the cooperating threads on screw shaft 55. It also makes it easier to move the grinding wheel assembly upward against the force of gravity than downward with its assistance.

Referring now to Figures 1 and 2, it will be noted that on the front side of carriage base 12, two trolley housings 85 form part of carriage 11. These trolley housings are similar to each other but of opposite hand. On the back side of carriage 11, two trolley housings 86 likewise form part of carriage base 12. Like trolley housings 85, trolley housings 86 are similar but of opposite hand. For reasons which will presently appear, trolley housings 86 are formed differently from trolley housings 85. Unlike trolley housings 85, which lack them, trolley housings 86 are provided with laterally operating roller bearing assemblies 87 and 88: see Figures 3 and 9.

Roller bearing assemblies 87 and 88 Hank rack 8 in the manner shown in Figure 9, being held in juxtaposition to rack 8 by supporting screws 89 and 90. The latter project upwardly into interiorly threaded openings 91 and 92 in the overlying portions 93 formed integrally with trolley housings 86. In all other respects, trolley housings 86 are substantially similar to trolley housings 85, being provided with similar trolleys, wheels, pintles and positioning screws. It is by means of roller bearing assemblies 87 and 88 in trolley housings 86 that carriage base 12 and therefore carriage 11 as an entirety is prevented from weaving as it travels back and forth along the runway formed by runners 6 and 7.

For convenience, the trolleys, wheels, pintles and positioning screws forming part of the trolley housings 85 and 86 will be described as they appear in Figure 7. This figure illustrates the arrangement of parts characterizing the trolley incorporated in the trolley housing 85 appearing at the left in Figure 3. As there shown, trolley 95 supports two like wheels 96 and 97 which turn on pintles 98 and 99, respectively. A positioning screw 100 operating on trolley 95 serves to hold trolley 95 in proper position in trolley housing 85. It also allows carriage base 12 and therefore carriage 11 to be tilted up or down, as desired, as is sometimes necessary to proper functioning of grinding wheel 34. A lock nut 101 keeps positioning screw 100 in the desired position of adjustment.

Extending from trolley 95 in trolley housing 85 at the left in Figure 3 to the similar trolley 95 in trolley housing 85 at the 'right invFigure 3 is tie rail 102. This tie rail appears inl elevation in Figure 7 and in section in Figure 8. `It serves to connect the two trolleys to each other, thus insuring their cooperation with each other and with the underlying runner. Tie rail 102 is attached to the two trolleys by means of bolts 103, the general arrangement being as indicated in dotted lines in Figure 3. In order to keep runner 6 free of debris, wiper assemblies 104 are fastenedvto the ends of the trolleys by screws v105: see Figure 7.

On the opposite side of carriage base 12, a similar tie rail 106 held in place by bolts 107 connects the trolleys in trolley housings 86, the same appearingin cross section in Figure l0.

Thus carriage 11, including the superstructure that forms part of it, is enabled to move back and forth over runners 6 and 7. Such movement is imposed on it by traversing motor 18, which operates on pinion 10 through shaft 20a (Figure 10). Pinion 10, acting upon rack 8 on runner 7, forces carriage 11 in that direction which corresponds to the direction of rotationy ofvtraversing motor 12. At any given time, this direction is determined by the position of a reversing switch (not shown) actuated by lever 110: see Figure 6. At the ends of the path of travel of carriage 11, depending on the direction of movement of carriage 11, lever 110 comes into contact with the trip assembly 111 or with the trip assembly 112, .both of which appear in Figure l. Trip assemblies 111 and 112 are adjustably positioned on runner 6, thus allowing for changes in path of travel of carriage 11. y t

A grinding machine of the kind described is, of course, susceptible of modifications by persons skilled in the art of designing grinding machines. For example, other means than the fluid cylinders shown and described may be used for supporting the grinding wheel assembly, which may itself be mounted on the superstructure in some manner other than that illustrated. The carriage may take some dilerent form, being differently organized at least insofar as concerns the trolley housings, trolleys and tracks on which it moves. Other means than those shown may be employed for moving the grinding wheel assembly toward and from the work. The latter need not be positioned on rails incorporated in the bed of the machine in the manner described but may be held in place in any desired way, as by clamps. Numerous other modifications are likely to suggest themselves to those skilled in the art.

When constructed in the manner described, grinding machines of the type to which the invention relates do have the important advantage that it is a simple matter for the operator to load and set up the work in the machine. They have the advantage of having a large capacity, being capable of taking manifolds, engine heads and even complete engine blocks. Leveling of the work after setting it up on jack screws or the like may be done easily in known ways. The work is fully visible, being face-up to the operator at all times. Usually there will be no need to check accuracy or to remove the work for close inspection of the finish, assuming of course that the work and the grinding wheel assembly have been properly located relative to each other.

A machine of the kind described, by providing a continuous ow of coolant through the spindle and grinding wleiel, permits the work to be ground while absolutely co With such a grinding machine so constructed, the operator has ready control over all phases of the grinding operation. All controls are located within easy reach of the operator, being for the most part on the same side of the machine as the operator himself. In this category are the power switch, coolant switch, wheel control, and the adjustable stops determining the length of travel of the carriage. Fine degrees of adjustment are possible. In simple machines, a constant speed travers-y the vlength of the ing motor is likely to be provided, but a variable speed motor can be provided instead if preferred; if so, the operator will be in a position tovary the traversing speed as well. Etfortless feed of the grinding wheel, up or down, is accomplished without lost motion in the mechanism. The operator does not have to watch the machine once it has been readied for operation; accordingly there is little or no reason for operator fatigue.

Notwithstanding its exibility, the machine is easily assembled and disassembled. It requires no undue amount of space in the shop. It can be made available to the purchaser at a cost materially less than the cost ofmore elaborate grinding machines of kinds known to the prior art. By virtue of favorable economic factors and other considerations, small shops, garages and service stations can compete effectively with larger shops inthe production of the high nish demanded by modern vhigh compression engines.

In the appended claims are summarized the principal features of patentable novelty residing in the invention.

What is claimed is:

1. In a grinding machine, a supporting structure; horizontally extending tracks on the supporting structure; a horizontally reciprocable carriage adapted to move along the tracks including a carriage base spanning the space between the tracks; superstructure extending upward from the carriage base; and, moveably supported on the superstructure, a work motor carrying a grinding wheel, the weight of the motor and grinding wheel being carried by pressure cylinders mounted in ball-and-socket seats in the carriage base.

2. A grinding machine according to claim 1 in which the pressure cylinders exert a lifting eiect at each of a plurality of widely spaced zones.

3. A grinding machine according to Aclaim 2 in which the spaced zones at which the lifting ei'r'ect is exerted are on diametrically opposed sides of the axis of rotation of the work motor.

4. A grinding machine according to claim 3 in which the pressure cylinders comprise two stationary cylinders each of which incorporates a moveable piston carried -by a piston rod.

' 5. A grinding machine according to claim 4 in which the two piston rods are coupled together by means of across bar that is 'rigidly attached to the housing of the work motor.

References Cited in the tile of this patent UNITED STATES PATENTS 946,635 Franke Jan. 18, 1910 1,233,120 Patch July 10, -1917 1,698,970 Shai Jan. 15, 1929 1,706,402 Hawn Mar. 26, 1929 1,827,688 Ley Oct. 13, 1931 1,854,493 Stable Apr. 19, 1932 2,023,347 Van Valkenburg Dec. 3, 1935 2,075,369 Stetler Mar. 30, 1937 2,128,023 Specht et al Aug. 23, 1938 2,197,729 Miller Apr. v16, 1940 2,418,738 Talboys Apr. 8, 1947 FGREIGN PATENTS 435,400 France Feb. 28, 1912

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