US1849160A - Adjustable tap - Google Patents

Description

March 15, 1932. E. A. WALKER ifi w llfifi ADJUSTABLE 'TAP Filed July 27, 1929' 30 bars.

Patented Mar. 15,1932

- (UNITE u jsrArss* WORCESTER, MASSACHUSETTS ADJUSTABLE 'i'lip Application filed July 27,

This invention relates to taps particularly designed for cutting screw threads in holes of relatively large diameter, the threads being commonly of relatively fine pitch.

* It is the general object of my invention to provide a tap for such purposes in which the cutting teeth are formed on separate'cutter bars, and in which provision is made for accurate radial adjustment of said bars to compensate for wear or regrinding of the teeth.

A further object of the invention is to provide improved means for holding the cutter bars firmly seated in the supporting member or head. v

My invention further relates to arrangements and combinations of parts which will be hereinafter described and more particularly pointed out in the appended claims;

A preferred form ofthe invention is shown in the drawingsin which: V

Fig. 1 is a side elevation of my improved tap i Fig. 2 is an end view thereof, partly broken away;

Fig. 3 is a side elevation of one of the cutter bars; and

Fig. 4 is a partial end elevation, showing the manner of radially adjusting the Referring to the drawings, my improved tap comprises a supporting member 10 adapted tobe mounted upon a driving shaft or spindle in any convenient or desired manner.

The member 10 is provided with a series of V brace and closely engage the sides of the member 10. The projections 16 thus serve to effectively prevent axial or endwise movement of the cutter bars 14. I v V Cylindrical projections or bosses 18-project from the side faces of the member 10 and cutter ts); sei'mim. 381327.

'provideshoulder's 19 on which thejproieetions '16 abut and are supported,it being noted that the projections extend rearwardly, or in a direction away'from the teeth.

Segmental recesses 20' are formed in one? face of each bar 14 andprovide shoulders 22 '(Figs..2'and'3) adapted to be engaged by the enlarged heads 24 of binding screws 26, which a-re'threadedintothe member 10. The outer face of each'bar 14 is provided wit-hteeth'T by which the desired thread ma be cut.

nmvn'sr A. WALKER, or WORCESTER, MASSACHUSETTS, {ASSIGNORTOJOHN BIA'IH, or v Whehthe bars 14 are inserted in the slots 12 and theshoulders 22 thereof are engaged V by the heads 24 of the'bi-nding screws 26, the

"projectionslti will be firmly seated. on the shoulders19and'at'the' same time the bars 14 will be held from :aXial movement by the projections16.'

When the teeth onthe bars 14 become worn or arereground, the tap may be restored to i sizeby inserting shims '30'under each' of the ten-thousalndthsofgan inch under size,- the I Eta-p can be restored to full or standard size by inserting shims of three thousandths thick -method of adjusting thecutter bars is found so I ness under each of the projections 16. This to:be' more accurate andr liable than the adzjustingwdievices heretofore used, suchfas ad-. 2 t

-je'cti'on's 16]:1180 very eifectively'preserve the justing screws or slidable wedges. The 'pro-' ='aXial alignment of the cutter bars during 7 adjustment thereof.

i ':one or more shims 30' may be inserted under each I projection 16 before the tap is --initia11y ground to size,in'whichcase the tap may be adjusted to cut undersize byremoving shims 30 of the desired thickness. It is not necessary to remove the bars 14 from the member 10 to insert or remove the shims 30,

-but merely looseningthe screws 26 is suffi- V cient.

"'HaVingfthuS described-myinventionrand Fthe advantages'thereof, I @do' not wish toibe :limited'tothe. details herein disclosed, otherwise than as set forth in the claims, but what toothed edge and closely abutting the sides of said supporting member and thereby pre venting relative axial movement between said bar and said member, and means to hold said bars seated in said slots.

2. An adjustable tap comprising a supporting member having a plurality of axially extended slots spaced about its periphery, and a toothed cutter bar for each slot, each bar having an offset projection at each end thereof extending in a direction opposed. to the toothed edge and closely abutting the sides of said supporting member and thereby preventing relative axial movement between said bar and said member.

- 3. An adjustable tap comprising a supporting member having a plurality of axially extended slots spaced about its periphery, and a toothed cutter bar for each slot, each bar having an oflset projection at each end thereof extending in a direction opposed to the toothed edge and closely abutting the sides of said supporting member and thereby preventing relative axial movement between .said bar and said member, said member being provided with shoulders underlying vand supporting said offset projections.

4. An adjustable tap as set forth in Claim 1, in which each of the cutter bars has shoulders on one side thereof and in which said holding means comprises screws threaded in said supporting member and each provided with an enlarged head engaging one of said shoulders.

5. An adjustable tap comprising, a supporting member having an axially extending slot in its periphery, a cutter bar for said slot, said bar having teeth projecting radially outwardly and also having an offset projection at each end thereof extending radially inward and closely abutting the sides of said supporting member thereby to prevent relative axial movement between said bar and said member and means insertable between one of said projections and said member for adjusting the relative radial position of said bar in its slot.

6. An adjustable tap comprising a supporting member having an axially extending slot in its periphery, a cutter bar for said slot, said bar having teeth projecting radibetween one of said projections and said member for adjusting the relative radial position of said bar in its slot, said member being provided with a shoulder overlying and supporting said projections.

In testimony whereof I have hereunto affixed my signature.

ERNEST A. WALKER.

ally outwardly and also having an ofl'set pro- I jection at each end thereof extending radially inward and closely abutting the sides of said supporting member thereby to pre vent relative axial movement between said bar and said member, and means insertable

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