US2706918A

US2706918A - Multiple bit attachment for drilling tool

Info

Publication number: US2706918A
Application number: US345635A
Authority: US
Inventors: Leland F Blatt
Original assignee: Individual
Current assignee: Individual
Priority date: 1953-03-30
Filing date: 1953-03-30
Publication date: 1955-04-26
Anticipated expiration: 1972-04-26

Description

April 26, 1955 L. F. BLATT MULTIPLE BIT ATTACHMENT FOR DRILLING Toor.

Filed March 30, 1955 2 Sheets-Sheet l INVENTOR. LELN D F. BLATT JATTORNEY .April 26, 1955 l.. F. BLATT MULTIPLE BIT ATTAcmmENT FOR DRILLING Toor.

Filed March 5o, 195s 2 Sheets-Sheet 2 FIGA.

FIG. 3.

FIG.7.

INVENTOR.

LELAND F.BLATT mmf- United States Patent MULTIPLE BIT ATTACI-MENT FOR DRILLING TO L Leland F. Blatt, Detroit, Mich.

Application March 30, 1953, Serial No. 345,635

6 Claims. (Cl. 77-55) This invention relates to multiple bit drilling devices and particularly multiple bit attachments for drilling tools. Said invention may be considered an improvement on the adjustable drill guide and pilot disclosed by my Patent 2,461,716 of February l5, 1949.

An object of the invention is to establish a dr1ve connection from a stem to a plurality of bits, to dispose such connection within a housing journaling the stem and bits, and to guide such housing in travel to and from the work, the guide means having a portion for seating on the work, and said housing constraining the stern and bits to slide in unison.

Another object is to employ gears to establish the described drive connection.

Another object is to adjustably regulate the sliding advance of said stem and bits relative to said guide means, thus suiting the attachment to different thicknesses of work.

Another object is to employ a slide guide for said housing equipped with an extension Slidable in a support adapted for rigid attachment to a non-rotating portion of a drilling tool, said support carrying an element engageable with the slide guide to limit advance of the stem and bits, and such element being adjustable to regulate such advance.

Another object is to equip said slide guide with a dowel for reception in an opening of the work, and to thus predeterminedly locate the bits with relation to such opening.

Another object is to provide a spring effective to retract the driving stem and bits to an initial drilling position with relation to said slide guide.

These and varous other objects are attained by the construction hereinafter described and illustrated in the accompanying drawings, wherein:

Fig. 1 is a side elevational view of my improved attachment.

Fig. 2 is an axial sectlonal view of the same as applied to a drilling tool, omitting the cover of the slideguide.

Fig. 3 is a cross sectional view taken on the line 3 3 of Fig. 2 and particularly showing a provision for clamping my attachment to a drilling tool.

Fig. 4 is a front end view of the slide-guide.

Fig. 5 is a perspective view of a key used to interlock certain parts of the attachment.

Fig. 6 is a cross sectional view of the slide-guide and of a gear housing within such guide, taken on the line 6 6 of Fig. 2.

Fig. 7 is a cross section on line 7 7 of Fig. 2 showing how the bits are guided at the front end of the slide-guide.

Fig. 8 is a perspective View of the gear housing.

In these views, the reference character 1 designates the frame of a drilling tool, 2 a shaft journaled in said frame and usually driven by an electric motor (not shown), and 3 a chuck carried by the shaft 2 and gripping a bit in ordinary use of said drilling tool. My attachment comprises a stem 4 for insertion in said chuck, and a guide support including a split collar 5 adapted to be clamped on the frame 1 by a screw 6, an arm 7 integrally projecting from said collar alongside the chuck, a head 8 on the front end of the arm projecting across the front end of the chuck, and an elongated tubular member 9 rigidly forwardly projecting from the head 8 and coaxial with the stem 4. The head 8 has an opening 10 accommodating the stem and affording it clearance. Slidably fitted in the member 9 is a tubular extension 11 from 2,706,918 Patented Apr. 26, 1955 ICC the rear end of a slide guide 12, said memberand extension jointly housing a coiled spring 13 tending to retract the

drilling tool

1, 2, 3 and the

support

5, 7, 8 9 to a desired initial drilling postion. A key 14 set into an elongated recess exteriorly formed in the member 9 has an inturned forward end 14a projecting into a slot 15 longitudinally extending in the extension 11, such key thus restraining the slide guide 12 from rotation and serving also to limit forward actuation of the slide guide by the spring 13.

Slidable forward and back in the guide 12 is a rectangular housing comprising front and

rear parts

16 and 17 rigidly interconnected by screws 18. Stub shafts 19 carrying pinions 20 are journaled in said housing in parallelism with and at opposite sides of the stem 4, and are meshed with and driven by a pinion 21 fixed on said stem. Screwed into the two stub shafts are a pair of forwardly projecting bits 22 having a sliding tit in a workengaging projection 23 formed on the front end of the guide. The length of such bits is such that their cutting ends are in close proximity to the work-engaging face of the projection 23, when the

housing

16, 17 is fully retracted, as in Fig. 2. In event the work 23a is to be drilled at opposite sides of an opening therein, the projection 23 may be equipped centrally thereof with a dowel pin 24 to be slip-fitted in such opening. Between the front end of the stem 4 and a screw 25 inserted in the housing member 16, there is interposed a ball 26 minimizing friction as a forward thrust is transmitted from the stem to the housing. Between screws 27 inserted in the housing member 17 and the two stub shafts there are inserted balls 28 minimizing friction as thrust is transmitted to said shafts from the housing. The slide guide preferably has a removable cover plate 29, said guide having one of its faces grooved to accommodate such plate and opposite edges of the groove being undercut to retain the plate in place. A screw 30 normally holds the plate in its closure position by securing a lug 31 on the plate to the front end of the guide.

A nut 32 is threaded on the member 9 for a forward and back adjustment regulating the spaced relation of such nut to the guide 12 and a locknut 33 is adapted to secure such nut in any desired adjustment. Thus when said guide is seated against a piece of work, the nut 32 limits advance of the stem 4 and of the bits moving in unison with such stern, so that the cutting stroke will not materially exceed the thickness of the work. This will safeguard the bits from damage through encountering any member disposed rearwardly of the work, and in some instances will avoid a mutilation of such a member. It will be noted that the projection 23 is cut away at opposite sides thereof as indicated at 34, a short distance rearward of the work-engaging face of said projection. The openings 34 partially expose the bits 22 and allow a discharge of chips. Afording the bits a slip t in the forward end portion of the guide 12 and in the projection 23, avoids undue lateral flexure of the bits and consequent breakage or deformation of drilled holes.

While the attachment illustrated is equipped with two bits, it is evident that a greater number of bits could be employed and driven by the described mechanism.

What I claim is:

1.. A multiple bit attachment for a drilling tool compr1s1ng a rotatable and reciprocable driving stern and a plurality of bits parallel to such stem, a drive connection to the bits from the stem, a housing for said connection reclprocable in unison with the stern, a guide having a front and a rear end and formed between such ends with a chamber proportioned to receive the housing and afford its reciprocation, the housing having a sliding t within such chamber and said bits being reciprocable in unison with the housing to effect their cutting stroke, and means on the front end of the guide for seating the guide on a workpiece, said stem projecting from the rear end of the guide to receive a drive.

2, In a multiple bit attachment for a drilling tool as set forth in claim l, a dowel pin forwardly projecting from said guide and having a predetermined lateral spacing from the bits for entering a workpiece.

3. In a multiple bit attachment for a drilling tool as set forth in claim 1, a ball at the axis of the stem transmitting forward thrust to the housing, and a ball at the axis of each driven gear transmitting forward thrust from the housing to such gear.

4. In a multiple bit attachment for a drilling tool, the combination with a drilling tool including a driven shaft, a nonrotative portion and a chuck on said shaft, of an attachment comprising a driving stem gripped by said chuck, a plurality of bits parallel to the stem, a drive connection to the bits from the stem, a housing for said connection reciprocable by such connection in unison with the stem, a guide formed with a chamber proportioned to receive the housing and afford its reciprocation, the housing having a sliding fit within such chamber, said guide having a front and a rear end, and said bits being reciprocable in unison with the housing to eiect their cutting stroke, a tubular extension from the rear end of said guide, a support for said attachment having a rear portion fixed on said nonrotative portion of the tool and having a tubular front portion in which said tubular extension is reciprocable, a spring reacting between the support and said extension to urge the guide forwardly, a stop element carried by said support and adjustable to and from the guide and engageable by the guide to selectively limit the effective stroke of the bits, and a connection between said extension and support restraining the guide from rotation relative to the support.

5. A multiple bit attachment for a drilling tool comprising a rotatable and reciprocable driving stem for engaging the chuck of such tool, a plurality of bits parallel to said stem, a drive connection to the bits from the stern, a housing for such connection reciprocable in unison with the stem, a guide formed with a chamber proportioned to receive the housing and afford its reciprocation, the housing having a sliding fit within such chamber, said guide having a front and a rear end and said bits being reciprocable in unison with the housing to etfect their cutting stroke, a tubular extension from the rear end of the guide substantially coaxial with said stem, a support attachable to a nonrotating portion of the drilling tool, such support having a tubular front portion in telescoping engagement with said tubular extension, means restraining said extension from rotation relative to said tubular front portion, a spring coiled about said stern and compressed between said support and guide to urge the guide forwardly, and means on the front end of the guide for seating on a workpiece.

6. .A multiple bit attachment for a drilling tool as set forth in claim 5, the last-mentioned means being a projection from the forward end of the guide and having guiding engagement with the several bits.

References Cited in the file of this patent UNITED STATES PATENTS 1,884,752 Krueger Oct. 25, 1902 2,302,853 Gordon Nov. 24, 1942 2,401,490 Little June 4, 1946 2,461,716 Blatt Feb. 15, 1949