US1536208A

US1536208A - Expansible boring tool

Info

Publication number: US1536208A
Application number: US2450A
Authority: US
Inventors: Gosper Amos
Original assignee: Individual
Current assignee: Individual
Priority date: 1925-01-14
Filing date: 1925-01-14
Publication date: 1925-05-05
Anticipated expiration: 1942-05-05
Also published as: FR597704A; GB244333A; DE460098C

Description

May 5, 1925e A. GOSPER EXFANSIBLE BORING TOOL Spe# Filed Jan. 14, 1925 ,..//fatented May 5, i925,

UNITED staresu PAT'ET OFFICE.

ASSIGNOR TO GEORGE HUGH FOSTER, SOUTH WALES, AUSTRALA.

EXPANSIBLE Application filed January To all 'whom it may concern:

Be it known that L AMos GrosPER, a subject ot' the King of Great Britain, residing at Camperdown, near Sydney, in the State of New South Wales, Commonwealth of Australia, have invented new and useful Improvements in Expansible Boring Tools (for which ll have filed application 1n Australia, Dec. 11, 1923), of which thel followin is a specification.

his invention-relates 'to an improved expansible boring tool for forming undercut holes in timber and other material, and it has been devised having for its principal object the provision of a boring tool that will accurately and expeditiously bore holes of uniform width for portion of their length but enlarged at their inner ends, while ,simultaneously with thaformation ofthe said enlarged portions counter-sinks are formed at the entrance ends of the holes. Holes so formed are used in the jointing o adjacent members in woodwork bythe use of trenails which are adapted to be expanded at their, end portions, and for various other purposes in joinery.

The invention provides an im roved expansible boring tool which is self-contained and furnished with means for stabilizing its operative integers, and means for synchronously returning the cutter and its control member to initial position immediately upon completion of boring.

Reference being had to the accompanying drawings Figure 1 is a perspective view of the improved expansible .boring tool.

Figure 2 is a vertical sectional view of the boring tool, showing the arrangement of its integers prior to boring.

Figure 3 is a vertical sect-ion showing the arrangement of the tool integers when that portion of the hole of'uniform width is being bored.

Figure 4 is a vertical section illustrating the integers of the tool when the lower eX- panded end of the hole isbeing bored and the entrance end of the hole is being countersunk. ,i

The improved expansible boring tool comprises a cylindrical casing 2 tted with a screw-cap 3, and having an upper ball bearing 4 and a lower ballV bearing 5 for a spindle 6 which latter is a slidable fit in a 0F MARRICKVILLE, NEAR SYDNEY, NEW

BORING TBL.

1e, man. aerial no. 2,4m.

7 at its upper end to facilitate the attachl ment of tthe boring tool to a drilling machine or the like, whereby the spindle 6 can be rotated at high speed.

Formed in the lower end of said spindle 6 is a slotway 8, wherein is accommodated a control tongue.9, that is pivoted at its lower end upon a short pin 10 in said slotway. This control ton e has a straight edge ortion 11, which oes not project eX- terior y of the spindle 6 and it is constructed having an upper end ortion 12 that inclines outwardly from said straight edge portion.

A tool-holder 13 is formed on, or may be afhxed to, the lowerl end of the pivoted control ton ue 9, and fitted in said toolholder is a oring tool or cutter 14 havin its op osite edges concaved and. thickene at its ower en A bevelled cutting member 15 is formed on the. lower end of the said tool holder 13, and it serves to countersink the upper end of the hole being bored by the tool.

Fitted around the spindle 6, beneath the upper ball-bearing 4 is a thrust collar 16 having fibre seating washers 17. A coiled spring 18 encircles the spindle 6 and the upper end of the control tongue 9, and it is seated against the lower ball-bearing 5 and the washers 17 on the thrust collar 16.

In use, the tang 7 is first connected to a drilling machine or the like, and the spindle 6 is rotated at comparatively highs eed and moved downwardly through the

bearings

4 and 5 in the casing 2 against the tension of the coiled spring 18. The boring tool or cutter 14 is thus brought against the work-piece and it bores a hole of predetermined depth and having uniform width, until such time as the outwardly projecting and inclined portion 12 of the pivoted control tongue 9 is forced inwardly into the slotway 8 by contact with the lower ball bearing 5-see Figure 4. As the upper end of the control tongue 9 is moved inwardly `into said s lotway 8, the tool holder 13 is moved slightly outwardly and the boring tool or cutter 14 is inclined to the axis ot the spindle 6 to progressively form a hole portion of increasing width at the lower end of 'the hole portion which is ofI uniform allwidth. Simultaneously with the outward' atI the lower end of the tool holder v13 bears.

against the work-piece and counter-sinks the. ent-rance end of the hole having its' major portion of uniform width.

The tension exerted upon the coiled spring 18 encircling the'spindle 6 during the feeding movement of said spindle ensures the synchronous return of the cutter 14 andthe pivoted control tongue 9 to initial position immediately following the boring of a hole of the character described.

The lower end of the cylindrical casing is, or mav be, provided having spikes 19 to grip t e work-piece,,and said easing may also be formed having milled portions 20 to enable a tight rip to be maintained upon the tool during oring operations.

It will be readily understood by artisans that dii'erent cutters 14 can be interchangeably fitted in the tool-holder 13 and that required adjustments can be made in the integers of the improved expansible boring tool whereby holes of different length and having varying degrees of undercut at their lower ends can be rapidly formed.

What I do claim is 1. An expansible boring tool comprising, a casing, an upper and a lower ball-bearing in said casing, a spindle longitudinally movable in said ball-bearings, a slotway formedin said spindle, a tongue pivoted at its lower end in said slotway, an outwardly `said tongue heilig adapted to contact with the lower ball-bearing when a hole of uniform width of required depth has been bored`and thus cle-align said cutting tool to undercut the hole and complete the boring operation. i

2. An expansible boring tool according to claim 1, wherein the tool-holder is Constructed having a bevelled cutting member to form counter-sinks at. the entrance ends of the holes being bored simultaneously with the undercutting of said holes at the inner ends.

In testimony whereof I affix my signature in'presence of two witnesses.

AMOS GOSPER. Witnesses:

M. STARFIELD,

W. J. CREAGH.