US3002323A

US3002323A - Surface grinder

Info

Publication number: US3002323A
Application number: US500365A
Authority: US
Inventors: Parks M Adams
Original assignee: Individual
Current assignee: Individual
Priority date: 1955-04-11
Filing date: 1955-04-11
Publication date: 1961-10-03
Anticipated expiration: 1978-10-03

Description

Oct. 3, 1961 P. M. ADAMS 3,002,323

SURFACE GRINDER Filed April ll, 1955 3 Sheets-Sheet 1 PARKS M. ADAMS INVENTOR.

ATTORNEY N In FIGS

TTTTTT EY P. M. ADAMS SURFACE GRINDER Oct. 3, 1961 5 Sheets-Sheet 3 Filed April 1l, 1955 PARKS MADAMS INVENTOR. BY C]d Www ATTORNEY 3,002,323 SURFACE GRINDER Parks M. Adams, 1211 Stevenson Lane, Towson, Md. Filed Apr. 11, 1955, Ser. No. 500,365 6 Claims. (Cl. 'S1- 102) The present invention relates to grinders and more particularly to that type known `as surface grinders. This type of grinder is especially adapted to the type of operation used to provide a dat surface at the mating surfaces of cylinder blocks and heads, but may also be used for other types of work where a smooth and flat ground surtace is required.

Although there are many types of surface grinders already existing, noue has yet been provided which will satisfactorily grind such items as cylinder blocks and heads, but which is relatively simple in construction and capable of producing a high quality of groundsurface. Because the mating surfaces of a cylinder block and its head must be substantially at, in order to provide a satisfactory seal with the thin head gasket, it is often necessary, when reconditioning an automotive engine, to regrind the cylinder head and the block. Because the character of the ground surface depends largely upon the speed of the grinding wheel, the vrate at which the work is fed to the wheel, and the amount of material removed in each pass of the work across the Wheel, it has previously been difficult to obtain a satisfactory surface without the use of an elaborate grinding process.

It is the object of this invention, therefore, to provide a simple, economical and practical grinding machine which will produce ya true and flat surface without the use of elaborate grinding techniques. n

It is another object of this invention to provide a grinding apparatus which will permit the use of a high speed grinding wheel.

In the drawing:

FIGURE l is -a plan view of the machine contemplated by this invention.

FIGURE 2 is a side elevation view ofthe machine.

States Pate t FIGURE 3 is an enlarged fragmentary sectional view taken along line 3--3 of FIGURE 1.

FIGURE 4 is an enlarged sectional view taken alon line 4-4 of FIGURE l.

FIGURE 5 is a fragmentary detail view of the grinding wheel bearing and its adjustment.

FIGURE 6 is a sectional view taken along line 6 6 Yof FIGURE 2 and showing the concave curvature of the work table of the machine.

The grinding machine, as shown in FIGURES l and 2, is composed of a base l which is mounted upon suitable legs or supports 2. A pair of work; supporting

plates

3 and 4 are carried on the base 1 to form a work table. The adjacent edges Z5 and 26 of the

plates

3 and 4 respectively, are cut diagonally and spaced apart to form a diagonal slot extending -across the grinding table as shown in FIGURE l. The outer edges of vZ7 and 28 of the plates are arranged higher than the diagonal inner edges so that the plates slope inwardly toward the opening, the amount of the slope being generally less than .002 inch per foot. The slope of the plates has been exaggerated in the drawing for illustrative purposes.

A pair of

side rails

5 and 6 extend one along each side of the

support plates

3 and 4 and an adjustable guide 7 is carried by side rail 6 to provide a guide for the work during the grinding operation. Guide '7 is carried by a group of members 8, 9, 10 and l1 which pass through suitable apertures in side rail 6 and are secured in position by set screws 12, soi that the guide may be adjusted laterally and secured in position as desired.

Positioned diagonally across the work table in the slot between

plates

3 and 4 is a suitable grinding wheel 13 of comparatively small diameter which is adjustable vertically relative to the upper surface of

plates

3 and 4. The grinding wheel is mounted on a shaft 14 which is supported in

bearings

15 and 16 at each Side of the Work table.` The bearings are mounted in

adjustable bearing blocks

17 and 18 respectively, which are in turn suitably supported for vertical. adjustment in

frames

19 and 20. Adjustment is eiected, as best shown in FIGURE 5, by means of a hand Wheel 21 which is fixed to the lower end of the shaft 22. The shaft threadedly engages the lower portion of frame 19 and the upper end of the shaft engages the lower portion of the bearing block 17' so that rotation of the shaft by means of hand wheel 21 is effective to move the bearing block vertically within the frame 19. Shaft 2.2 also carries a sprocket wheel 23. A similar arrangement is provided at the other side of the Work table to provide for adjustment at the other end of the grinding wheel shaft :14. A chain 24 extends between and engages the sprocket wheels so that both ends of shaft 14 may be simultaneously adjusted by rotation of hand wheel 2l. n

The grinder may be powered in any suitable manner, the arrangement depicted in the drawings consisting of a motor 29 which is set at lan angle to the table and supported so that its drive shaft 30 is parallel to the shaft 14 whi-ch carries the grinding wheel 13. V-pulleys 31 and 32 are mounted on

shafts

14 and 30 respectively, and carry a V-belt 33. Idler 34 is provided to take up the slack in belt 33, which is made long enough to allow vertical adjustment of the grindingwheel 13.

Since the best ground surface is provided by a high speed grinding wheel, and the maximum permissable feed and depth of cut is limited by the heat generated by the cutting action of lthe grinding wheel, it is generally not possible to complete the grinding operation in one pass across the grinding Wheel. Thus, previous attempts at a simplified form of grinding mechanism which utilize the wood planer principle of setting the two halves of the work table on different levels on opposite sides of the grinding wheel have not been successful since such an arrangement does not allow the work to be returned across the grinding wheel after the initial pass. That is, if more than one pass is needed to grind ofr the desired amount of material, it is necessary to remove the work from the table after the initial pass and reposition it for each subsequent pass across the grinding wheel. If both halves of the Work table in such a machine are set at the same level to allow the work to pass in both directions, satisfactory results still cannot be obtained because there is no support for the ground portion of the work once it has passed across the grinding Wheel. Obviously, when using suc-h a machine, since the center of gravity of an object being ground generally lies at or near the mid-point thereof, relatively greaterv grinding pressure will be exerted by the weight of the object when the center of gravity is directly over the grinding Wheel thanwhen the ends of the object are passing over the wheel, causing more material to be removed from the center of the'work than from the ends, and producing a concave surface.

To eliminate this difculty, the machine herein proposed has its

Work supporting plates

3 and 4 arranged as hereinbefore described so as to slope inwardly toward the grinding wheel at an inclination of .002. per foot or less, slopes within this range having been found by experimentation to give the desired result. As may be seen in FIGURE 3, as the work 35 passes across the grinding wheel, it is supported at its extreme ends on the upper Vsurfaces of the inclined suporting plates 3.and 4, so that as the center of gravity of the work approaches the grinding wheel, the position of the points of support with relation to the wheel changes to support the worl; at the proper height above the wheel to allow substantially the same amount of material to be removed from the center of the work as from the ends. The amount of slope necessary to provide a uniform grinding pressure across the entire surface being vground will vary with the length, thickness and type of material of the object being ground, vand can be determined experimentally. Experience -with machines constructed in accordance with this invention jhas shown that Acylinder heads, blocks `and similar items Vcan be ground lby theuse of this method to have a fiat surface well within the tolerance necessary for providing a goodv seal when yassembled with a conventional cylinder `head gasket.

When reconditioning used cylinder heads an dblocks, it is sometimes desired to grind the surface in such a ymanner as to remove more from one side than the other in order to make the surface true. This is easily accomplished in the herein contemplated machine by use of the arrangement depicted in .FIGURE 6. Work supporting plates 3` and 4 are formed so that their upper surfaces are concave as shown, the amount of curvature being exaggerated in the drawings for clarity in illustration. By adjustment of guide 7, the lateral position of the work may be selected so `that the work is suported on the plates 3 fand `4 with one side of the work higher than the other by any desired amount within the limits of the .concavity of the plates. Thus, the surface of the Work may be corrected for any lateral deviation in tnleness simultaneously with the normal grinding operation.

The above arrangement is also effective when the object being ground is heavier atone side than at the other, as is the case with cylinder heads in which the cylinders are disposed along one side of the head. When such objects are ground, a relatively greater grinding pressure will be exerted at the heavier side as the work passes over `the grinding wheel, causing more material to be removed from that side than from the other. This condition may be compensated for by selecting the proper lateral position for the work as above described.

Although in the drawings the grinding wheel is depicted as being arranged at an angle with the direction of motion of the work across the wheel, it is to be understood that the wheel may be arranged so as to be perpendicular to the line of motion, the angular arrangement being selected to give the most satisfactory character to the ground surface.

A machine constructed and operated in accordance with the principles herein set out will grind a true and at surface within very close to-lerances, and will permit the most advantageous combination of grinding wheel speed, work feed and depth of cut by allowing the work to be passed back and forth across the grinding wheel` the required number of times to remove the necessary amount of material, thereby overcoming the limitation inherent in planer type machines having work suporting tables set at different levels and which, therefore, yare limited to a single pass during the grinding operation.

While but ,one embodiment of the present invention has `been shown and described, it is to be understood that relongated opening formed therethrough, the upper surface of said table being formed in two halves each extending outwardly from said opening and sloping upwardly therefrom, each said half of said upper surface being concavely curved in a direction normal to the slope of said upper surface, a cylindrical grinding element mounted within said opening and vertically adjustable with respect to said upper surface of said table, and means for 'rotating said grinding element.

2. A machine comprising, means forming an elongated table having a transverse slot formed therein,

the upper surface of said table being divided into two portions by said slot, each said portion being sloped from said slot upward to the outer end of said portion, each said portion being concavely curved in a direction normal to the slope of said surface, cylindrical grinding means mounted within said slot ,and vertically adjustable with respect to said upper surface, and means for rotating said grinding means.

3. A grinding machine comprising, an elongated table forming an upper surface having an elongated opening extending therethrough, said upper surface being formed in two portions extending outwardly and upwardly from each side of said opening, the imaginary intersection of said two portions of said upper surface being generally transverse tothe longitudinal axis of said table, each said portion of said supper surface being concavely curved about an axis parallel -to the slope of said surface, a high speed cylindrical grinding element of relatively small diameter mounted within said opening between said two portions of said table and having its axis extending transverse to the longitudinal axis of said table and lying in a plane below said imaginary intersection, and power means connecting with said grinding element and operative to ,effect rotation thereof.

4. A grinding machine comprising, an elongated table having an upper surface and a narrow opening extending therethrough, the upper surface of said table being formed in two portions extending outwardly from opposite sides of said opening and sloping upwardly therefrom at an inclination off not `more 'than .002 of an inch per foot,

'eachsaid surface being concavely and similarly formed about an axis parallel to the direction of said inclination, a cylindrical grinding element of relatively small diameter mounted within said opening and having a supporting shaft extending entirely through the cylindrical axis of said grinding element, a bearing at each end of said opening to receive said shaft, vertically ixed guideways extending downwardly from the table for slidably receiving the bearing, means for simultaneously elfecting vertical adjustment of both bearings relative to said table, and Vmeans connecting with said shaft for rotating said grinding element.

5.r In a grinding machine, the combination of an elongated table having a continuous upper surface and a narrow opening extending transversely therethrough, the upper surface of said table being formed concavely about an axis parallel the longitudinal axis of said table, a cylindrical grinding element rotatably carried within said opening, and work guide meansextending substantially parallel to said longitudinal axis and laterally adjustable with respect thereto.

6. In a grinding machine, the combination of an elongated table having an upper surface and a narrow opening extending transversely therethrough, the upper surface of said table being formed in two portions extending upwardly and outwardly from opposite sides of said opening yat an inclination of not more than .002 inch per foot, said two portions of the upper surface of said table being concavely curved normal to the direction of said inclination, and a cylindrical grinding element rotatably carried within said opening.

References Cited in the Ele of this patent UNITED STATES PATENTS 857,757 Reid June 25, 1907 1,197,435; Bogue Sept. 5, 1916 1,961,487 Hamann June 5, 1934 2,598,020 Rutherford May 2.7, 1952 FOREIGN PATENTS 13,227 Great Britain July 23, 1900 12,712 Great Britain 1909