US1880377A - Valve grinding means - Google Patents

Description

Oct. 4, .1932. R 1,880,377

VALVE GRINDING MEANS Filed March 14. 1930 INVENTOR Her/02a Qz/er.

ATTORNEWS.

2o c On account ofa known tendency of grind- Patented Oct. 4, 1932 UNITED STATES ,iATENt OFFICE HAROLD I. DYER, or nnrnorr, MICHIGAN, Assrenon ro wILooX-nrcrr CORPORATION, A CORPORATION o1 mrcHIeAn VALVE GRINDING S Application filed March 14, 1930. serial No. 435,892.?

' and the like, it will be herein described with particular reference to valve grinding; and as applied to a grinding operation in which a valve head, of a usual mushroom type is centrally engaged by a fixed element while the valve is rotated by means of a chuck,"

the valve stem being supported, near said head by a so-called steady rest. The principles of the invention are, however, believed to render the same applicable also to certain centreless? grinding operations in which steady rests are used and to the grinding of various objects in which importance attaches to accuracy of fitand to an avoidance of scoring opposite a steady rest.

ing operations, of the character referred to, to produce scoring efiects in the region of contact of steady rests withvalve stems, it has been customary to defer the so-called finish-grinding of stems until after "the grinding of valve heads,rthe stems being then brought to final size. But this sequence of-steps, wherein the steady rest has engaged a comparatively imperfectsurface during the grinding of the head, has necessitated a rather wide tolerance of imperfection the grinding of the heads. It is a primary object of the present invention to efiect such a simplification and improvement in valve grinding means and methods as shall obviate the mentioned scoring and thereby render it practicable both to fin'ishgrind the stems in advance of the grinding of the headsand to substantially diminish the tolerance of error in the final grinding of either the peripheral portions or the seat portions of heads.

Apreferred expedient by which the foregoing results are obtainable is surprisingly simple, consisting essentially in the interposition of renewed portionsof a suitable sheet material, such as paper of appropriate quality, between the steady rest and the valve stem. The scoring effects to be obviated have been found to result mainly from fr a gments of steel, plating metal and/or abrasivemae terial which become lodged upon the steady rest,- -the hardness of thelatter being such as to support them as if for acutting efiect; and the solution of the mentioned problem has been found to lie'in the interposition and repeated renewal of .a suitable sheet material,.su c h as paper which is sufficiently hard firmly to support the vnv aem' and is nevertheless practically anti-frictional. It

should not adhere to the stem but should so yiel dably support any small particles that may become interposed beneath the stem as to obviate scoring thereof.

" To bring out the essential principles relied on, one of inany simple means that may be employed for bringing fresh surfaces of paper, or alike low-friction web into a position between a steady restand a valve stem is herewith illustrated; but the essentially d agrammatic character of this illustration,

and needle relative importance of the new.

method, as compared with any specific means for itsexecution, are especially emphasized;-

and other objects .of the present invention may be best appreciated from the following description of an illustrative embodiment thereof, Itaken in connection with the appended claims and the accompanying drawmg. i in Fig; lie, for the most part, an elevational view, a valve stem being shown as sectioned in a plane such'asthat suggested by line 1-1 of Fig; 2.

Fig. 2 is a plan view, taken substantially as suggested by the arrow 2 of 1'. 3 In Fig; '2, a valve V comprisinga head H and astem S is shown as disposed between a hired bearing element 13, centrally engagingthe head H,and a rotated chuck 0, 3 grindor G being forwardly movable during its rotation relatively to said head, and a steady rest or a pair of steady rests R, R being disposed beneath the stem S in proximity to the head H. a 7

Although the opposite inclination and also any sharp corners or like parts of the ter minal surfaces of the steady rest elements R, B may be favorable to the removable retention of a sheet of paper P thereby during rotation of the stem S, any suitable means may be employed to contribute to the supply, support, tensioning and/or convenient removal of the paper P. This is shown as a continuous strip terminating in a roll 1?; and this may be supported in any convenient way,as from the steady rest element R. For the purpose last referred to, bracket elements 10, 10 are shown as provided with inwardly bent ends 11, 11 suitably spaced for engagement of the rest R,,one of a pair of bolts 12, 12 being shown as provided with a wing nut 13; and a bracket element or ele ments 10, 10 may support not only a pivot or bearing element 14 for the roll P, through or into which a core or plugs 15, 15' may extend in a known manner (the pivot element 14 being shown as retained by a removable cotter 16) but also with any suitable means for advancing or controllingthe tension of the paper strip P. For the vpurpose last referred to, upwardly extending arms 17, 17 of the brackets 10, 10 may, for example, be provided with longitudinal slots 18, adapted to receive a transverse pressure-applying or strip-advancing element 19, if desired. The element 19 may have the form of a roller provided (preferably near the ends thereof, as at 20,20) with slight projections adapted to engage the paper or other strip material, and also with means, such as a crank 21, for rotating said roller.

It should not be overlooked that advantageous eflects may be obtained without the momentary retention of the paper, as the lat'- ter is depressed by the valve stem; but the described means are favorable to an avoidance of litter by the use of a continuous strip of the friction-obviating material; and, if'

desired, an end of the mentioned strip ma be'returned over or beneath the roll 19, or its i equivalent, in such manner as to providea loose protective loop over the stem S in the region of the rest or rests R, R. The handle 21 of the: roller 19 should be understood as merely suggestive of any desired mechanical means for advancing the paperP, in case this material is provided in strip form; but

ing of the stem being obviated;and the in-, vention' should not be understood to preclude either the finish-grinding of stems in an operation continuous with the rough grinding thereof or the adaptation of the mentioned web to an appreciable polishing effect.

The flexible sheet or strip of paper or other web employed should be neither so spongy as to defeat the function of the steady rest nor so hard as to exclude and elevate any particles received by said paper. Metallic foils or special fabrics are not known to possess any advantages commensurate with their higher cost; and it is suggested that in case a fine wire meshis to be employed, it be first subjected to a heavy flattening pressure. No oleaginous, resinous or mineral additions to the cellulosic ingredients of a suitable paper are necessary; but the resiliency thereof may, if desired, be such as to separate an upper lap 23 from a lower lap 24:, in case a loop is to be maintained in the paper strip without the use of special guides therefor. Such a loop should permit the free introduction and removal of valve stems; and, in order to gain a protective function from the upper lap and toobviate any dropping of particles therefrom onto unused portions of the strip, the direction of advance of said strip may be that indicated by the arrow 24:. Itwill be'understood, however, that the de-' tails referred to, as also the configuration of any non-rotary supporting means, such as a steady rest or rests, arerelatively unimportant and subject to wide variation.

Although the foregoing description has included details of but one embodiment of the present invention, it will be obvious not only that features thereof might be independently employed but also that various modifications, additional to any suggested herein, might easily be devised by skilled workers, if informed of the foregoing,all without dey parture from the scope of the present inven-l tion, as the latter is indicated in the following claims: 7 V

1. A valve grinding mechanism comprising means for supporting a valve in position for grinding, a pair of'brackets secured to said means, a shaft secured to said bracketsfor rotatably'supporting a continuous strip of low-friction web material and means including a roll, having a plurality of engaging elements for moving said strip between the supporting means and the stem of the valve.

2. A valve grinding mechanism comprising means for supporting a valve in positionfor grinding, a pair of brackets secured to the.

means, a shaft mounted on the brackets for rotatably supporting a continuous strip of paper material and means having a plurality of projections engaging said strip material, for moving said strip material between the supporting means and the stem of the valve. 7 HAROLD I; DYER.

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