USRE3147E - Improvement in machine foe ghindino and polishing saws - Google Patents

Description

@uitrit tstrs getraut @frn JOHN LIPPINCOTT, THOMAS BAKEWELL, BENJAMIN P. BAKEWELL, AND BENJAMIN BAKE- WELL, JR., OF PITTSBURG, PENNSYLVANIA, ASSIGNEES OF WILLIAM J. LIPPINCOTT.

IMPROVEMENT IN MACHINE FOR GBINDING AND POLISHING SAWS.

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T0 ALL WHOM IT MAY COGERN:

Be it known that WILLIKAM J. LIPPrNco'rT, assigner to JouN LIPPInco'rT, Tuoms BAKEWELL, BENJAMIN P- BjAKuwELL, and BENJAMIN BAKEWELL, Jr., partners, under the iii-m of Lrrpmcor'rw BAKEWELL, of thecity of Pittsburg, in the county of'Allegheny, and State of Pennsylvania, has invented-a new and useful Improvement in Machines for Grinding and Polishing Saws, which is also applicable to grinding and polishing sheets or plates of steel or other metals and we, the said assignees, do hereby declare the following to be a full, clear, and exact description th'ercof, reference being had to the annexed drawing, lforming part ofthis specification, in which- Figure 1 is a side elevation of his machine, viewed from the right-hand side.

Figure 2 is n. side elevation, viewed from the left-hand side.

Figure 3 is a longitudinal vertical section of his machine through the centre thereof.

Figure 4 is a transverse vertical section of his machine through z z, g. 1.

Previous to the introdrction of the inventionhereinafter described, the ordinary mode of grinding vand polishing long saws was to press them by hand on the periphery of`a grindstone, vwhich revolved rapidly by machinery, the saw being moved along over the stone by the workman asvthe grinding'progressed, the degree of pressure of the saw on thestone being regulatedv bythe-operator bearing-fdow-n with more or less'of the weight of his body upon the saw.

Thismode of operation was liable to many serious objections. The grindstones not being of uniform hardness throughout, tended naturally to wear away more rapidly at the soft places than elsewhere, and, as the saw was laid upon the stone, and pressed down upon it, the stone very soon acquired an hneven surface, the hard places projecting beyond its surface, where the stone was more abra'ded.

As soon as this inequalityincreased so as to impair the accurate rotundity of the stone to any considerable degree, it became necessary to chip off the hard projections, and dress down the stone to a true circle, which caused a great waste of the stone, and considerable expense and loss of time. i

Another mode of grinding saws was. to place them on a horizontal table or bed, to which the saw was secured by pins or clamps, the bed and saw traversing back and forth under the grindstone, which revolved on its axis above it.

This ,mode had also serious objections, the chief of which were the impossibility of moving the saw sideways under'the stone, according .as the back or edge needed most grinding, and the trouble of securing the sawplatc to the bed, and removing it'when it is required to be turned, the risingof the 'saw from the hed or table during the process of grinding, caused' by itselongation from the heat created by the friction ofthe stone, and its being coniincd by clamps at the ends, and the uneven surface produced by the sand washed from the stone getting between the bed-plate and the saw. It -was almost impossible, in practice, to -keep the bcd or table so accurately horizontal and perfectly level -as that the distance between thepgrinding-surface of the stone and the hearing-point of the table (which was constantly changing) should be so entirely uniform that there should be no perceptible variation in the" thickness of a long saw-plate.

By both of these methods it was, and still is, very diiicult to make the saws of uniform thickness throughout their entire length, whereas uniformity of gauge is a very important desideratum; and, as cast-steel sawplates are almost invariably thickwer at one end than at the other, before being manufactured into saws, it is a matter of great nicety not only to remove the scale vand polish the metal, but also to grind it down to a. uni

form gauge By the machine hereinafter described, all these diicultics are effectually overcome,'pa.nd not only is the work of grinding and polishing saws performed much more expeditiously than by the old process, and a great saving in the grindstones effected, and uniformity of gauge secured, but also the gauge is regulated to any required thickness of plate, and the saw so ground as to reduce its thickness at the back more than at the teeth, so as to give it clearance, and prevent friction ir. thc'use of' the saw.

These importantresults are accomplished chiefly by using a restor vhearing-roller or support, preferably of comparatively smallldiameter, so as to give a small bearing-surface, said roller or support having its axis in the same vertical plane as that of the grindstone, whereby is secured a. bearing-surface which, if thc roller be accurately cylindrical, is unvarying in its distance from and parallelism with or inclination tothe surface of the grindstone, and which, as it constantly revolves,.is kept free from the accumulation oi' sand by the water always used in the operation of grinding. Y

To enable others skilled! in the art to construct and use this improved machine, we will proceed to describe its construction and operation.

In the drawinga is the rectangular frame or bed of the machine, from the opposite sides of which rise two strong sta'nd` ards, b b', each of which has a vertical slit, c, extending from the to'p downwards a suicient distance so as to raise and lower the pillar-hlocks d d', o1' boites which carry the ljournals e e' ofthe shaftf, to which the grindstone g is secured. o

The journal-boxes d rl are made with a deep groove on each side, to receive the face of the standards b b', on each side of the slit c, so that one journalboxd, may slide up and down in the slit ot' each standard b, as

between ways.

The grindstone-shaft f is' placed horizontally aci-oss the machine, between the journal-boxes d d', in which it revolves, andthe grindstone is attached to the shattfmidway between the standards b b, at about the centre of the machine. l'

The grindstono is circular, with a plane face orperiphery parallel to the axis of the shaftf. The journalboxes carrying the vgrindstone are each attached to and supported by an upright iron rod, h, placed in the centre of the slit c,4 in which slides t-he journal-box, to which rod it is attached at its upper end by a pin, z'.

The lower partof eachl rod h has` a screw c ut in it, which takes 'into a female screw inthe. centre of a large cog-wheel, It, one such cog-wheel k being connected with each rod, h, and theccntral part of the cog-wheels It k', resting upon their respective standards ILL', as seen ings. 2 and 4, sustain'the weight of the grindstone` The cog-wheels project each through a narrow opening made for that purpose, near the base of its standard.

' The'two cogfwheels .7c 7c are on the same horizontal plane, and between them, connecting them together, so as to cause them to rotate in the samedirection, isa pinion, l. The cog-wheels k c' being of the same diameter, and the pitch of the 'screws on the rods h h being equal, the turning of the cog-wheels c t by the pinion l causes the rods huhto rise o'r descend equally, thus' raising or lowering the journal-blocks d d uniformly, and preserving the exact horizontal position of the grindstone-shaft, which is elevated or depressed by turning the pinion Z. i A I v The revolution of the pinion l, in either direction, is e'ected'bythe bevel-wheels m m', one attached to the shaft of lthe pinion l, 'and the other to a horizontal shaft, "it, whichv terminates at the rear end of the machine, in a crank, p. i I

Immediately under the axis of the grindstone, andparallel with the shaft j', is a horizontal cylindrical roller or support, q, which extends across the machine, its :journals resting onblocks r r', projecting from the inside :of the standards b b', (sce iig. 4.) v p This roller has n o other motion than that on its axis, caused by the passage of the saw over` it, and serves as a rest or support for the saw-plate, sustaining the pressure of the grindstone upon the saw, the degree of which is regulated by the depression of the journal-boxes d d', in the 'manner described, V

At a suitable distance in front and rear of the rest or roller, q, are placed a pair of horizontal friction feedrollers, s .s s' s', the pressure of which vis regulated by the set-screws t t so as to'suit different thicknesses of steel plate. 4

The upper surface of the lower fecduoll of each set is in the same horizontal plane as the upper surface of the rest-rollcr or support q, under the grindstone, so as to keepthc saw perfectly straight.

The lower roll of cach pair-vof friction-rolls has a cog-wheel, u u', attached to its axis, and these are connected together by a train of pinions, v u, and cog-wheel '10,50 as to cause them' to revolve in the same direction and with the same speed, a regular motion being communicated to them by the crank x.

The twofriction-rollcrs s s, in each set, are geared Vtogether by pinions a'.

The operation of this machine is asl'ollows: l

, The grindstone is adjusted to the proper height, so that its periphery, as it revolves over thc'rest-roller g, `will Vtouch and grind the saw-piatte, (marked y in thedrawing, l which adjustment is effected by turning the crank p, so as toraisevor lower the storie. The grindstonc is caused to revolve by power applied to the pulley m, on the v shaft f. The feed-rollers s s s s are set in motion by the crank :u and train of gea.ringvheels,A and revolve in such a direction as to causo the saw to pass forward, while the grindstone revolves in contact with it in the opposite direction. I I p As the centre ol motion of the grindstone is fixed, its shaft, f, being held in the position in which it was ,set by the rodsh h', the grindstone will wear uniformly at all points, which would not be the case if it rested on the saw with its bearings loosel, so that itfcould risc and fall. l

As the stone gradually wearsaway, the bearings of thcjournals ofthe shaft fare lowered, by turning the rods L h', by means of the crank p.'

If it is desired to grind down the back of the saw-plate thinner than the teeth, it may be done by giving the rest or support q a slight inclination. Il' prcfcrredthc support q, instead of turning freely in its bearings,

' may be attached to the cogfwheel w, forming one of the train of wheels connected with the feed-roller`s .s es s',

in whichcuse it will revolve with them, and should then be oi the same diameter.

The position of the rest or support g, under the grindstone g, and with its axis in the same vertical plane al the axis of the grindstone-shaft f, in connection with the mode of hanging the stone and elevating and depressing it, enables us to make an aperture or passage of any required depth, to which any metallic plate passed between the stone and the rest is made to conform, the stone reducing-it to the gauge vthus establlshed.

This apparatus may be used for grinding and polishing not only long saws, but other sheets or plates of steel, or other metal which requires to be dressed and polished.

Having thus described this improved machine for grinding and polishing saws, what we claim as new, and

as the invention of WILLIAI J. LIPPINcor'r, and desire to secure by Letters Patent, is I A machine for grinding and polishing long,r saws, consisting of a grindstone, supported on adjustable bearings, so as to bo raised or lowered at pleasure, in the manner described, and having a cylindrical support for the saw-plate to rest upon as itis being ground, the axis of which is in the same vertical -plane as that of the grindstone, and with ono or more pairs of feed-rollers, having pressure-screws, or their equivalent, so as to hold and guide the saw in its passage under the stone, such feed-rollers being geared so as to have a positive and continuous motion on their axes in suchdrection as to feed the saw-plate forward either with or against the motion of tho revolving grindstone, substantially in the manner and for the purposes herenbefore setforth.

In testimony whereof, we have hereunto set our hands.

JOHN LIPPINCOTT. THOS. BAKEWELL.

BENJ. P. BAKEWELL.A B. BAKEWELL, Jn.

Witnesses:

B. B. Klan, WiL-N. Hovlrsxua.v G. H. CnaIsrY.

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