US3694967A

US3694967A - Double insulated drill bit sharpener

Info

Publication number: US3694967A
Application number: US76693A
Authority: US
Inventors: Henry J Stielper
Original assignee: Black and Decker Manufacturing Co
Current assignee: Black and Decker Corp
Priority date: 1970-09-30
Filing date: 1970-09-30
Publication date: 1972-10-03
Anticipated expiration: 1989-10-03
Also published as: FR2107327A5

Abstract

A double insulated drill bit sharpener including an electric motor supported within a casing and including an output rotary shaft. A sharpening head is fixed to the casing and includes a sharpening wheel fixed to a rotatable spindle coupled to the motor driven shaft.

Description

Oct. 3, 1972 United States Patent Stielper "RRRTRRRR .5 N444044HU 33373311 HHHHHHHJ 35 55 In m m wk cm u "83 1 m m mfim "m m d e 0 t LE-l O n i h UMME f RM HSP MGW B 1 7 wwwwwxw 999999999 HHHHHHHHH 2398882 9 35070590 09259538 3J9fi 3040 484 2577492 4 2 2222223 n. u mm T m I m H m L .U r. m M D 0 D mm 7 m k 0 w A CT 9 J h 0 u n m a n L 6 S n um mum N H .I 7 E m L r e W" w W N A m i d w OH m s "m P DS I A F A l 1 1 1 M 2 3 2 I. 5 l U U U n d E u m .m a m ..m d m .m lo r S m Y m. "h e p rm a n G m .u m y b m H mm mm d Tm m m y .m mi mu .m E M h U D m rd 1 mm m m d 6 8 UQWWH QhmR 51 1 mJ i 1R m9B U5 mu 54 n B 2 4% R/ no 1 F 1 MR0 W mm m m M m mm m mhl m m U 1 d 5 M U Mr. H UN 5 55 electric motor supported within a casing and including [56] References Cited an output rotary shaft. A sharpening head is fixed to UNITED STATES PATENTS the casing and includes a sharpening wheel fixed to a n w d r. f u m .w 0 F m m e m m m m M mm c m w c d 0 n l D.

RR 55 44 33 NH f n mm &m n MD '8 5S 99 NH 006 Willi PATENTEDunr 3 m2 SHEET 1 [IF 2 INVENTOR.

PATENTEDB SHEET 2 OF 2 FIG. 5

INVENTOR- R/ E D- L F TM Q Y\ R N m DOUBLE INSULATED DRILL BIT SI-IARPENER SUMMARY OF THE INVENTION The present invention is directed to an electric powered, drill bit sharpener which includes a casing having an electric motor disposed therein. A sharpening head including a rotatable wheel is supported upon the casing. The wheel is driven by the motor through a unique coupling which accommodates small tolerances and misalignment between parts. Also, the coupling and casing are constructed to double insulate the unit for operator safety.

Main objects of the present invention are to provide an electric powered, drill bit sharpener which is double insulated and which utilizes a unique coupling between a sharpening wheel spindle and a driving motor output shaft, which coupling electrically insulates the former from the latter and, in addition, accommodates small tolerances and misalignment therebetween.

Further important objects of the present invention are to provide a novel drill sharpener of the above character which is compact, light weight, safe and efficient.

Additional important objects are to provide a drill sharpener of the above character which is relatively inexpensive to manufacture, rugged in construction, and reliable in use.

Other objects and advantages of this invention will become more apparent from a consideration of the detailed description to follow taken in conjunction with the drawings annexed hereto.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view illustrating a drill sharpener embodying the present invention;

FIG. 2 is a sectional view of the structure of FIG. 1 taken along the line 2-2 thereof;

FIG. 3 is a top plan view of the structure of FIGS. 1 and 2 to a larger scale;

FIG. 4 is an exploded perspective view of the lower portion of the sharpener casing construction;

FIG. 5 is a sectional view of the structure of FIG. 3 taken along the line 5-5 thereof;

FIG. 6 is a perspective view of the coupling utilized in the present invention.

BROAD STATEMENT OF THE INVENTION Broadly described, the present invention relates to a drill sharpener including a casing, an electric motor supported within said casing and having an output rotary shaft, a sharpener head fixed to said casing, said head having a spindle rotatably supported thereon, an abrasive sharpening wheel fixed to said spindle, a torque transmitting coupling having at least one end thereof formed of hollow, cup-shaped configuration loosely and non-rotatably receiving one end of said spindle, said coupling having its other end threaded into said shaft, whereby to electrically insulate said shaft from said spindle and accommodate small tolerance variations and misalignment therebetween.

In still another aspect, the present invention relates to a drill bit sharpener comprising a motor housing having an electric motor therein, an electrically insulating casing including first and second telescoped members enclosing said motor housing, a baffle fixed within one of said casing members and supporting said motor, said baffle being constructed of electrically. insulating material and cooperating with said one casing member, whereby to retain electric conductor means in place within said one casing member, a sharpener head including a body fixed to said casing and having a spindle rotatably supported thereon, an abrasive wheel fixed to said spindle, said motor having a rotatable output shaft, and insulating means coupling said motor shaft to said spindle.

In yet another aspect, the present invention relates to a drill sharpener comprising an electrically insulating casing, an electric motor supported within said casing and having an output shaft, a sharpener head fixedly supported upon said casing, an abrasive wheel encased within and rotatably supported upon said head and coupled to said shaft, said abrasive wheel having a conical end face defining a sharpening surface, said head having means thereon to guide and support selected sized drill bits with their cutting lips in stationary sharpening engagement with said sharpening surface.

In still another aspect, the present invention relates to a drill sharpener comprising an electric motor enclosed in a housing, said motor having transmission means within said housing and an output shaft accessible from outside said housing, an electrically insulating casing substantially completely enclosing and trapping said housing therein, a sharpener head fixedly supported upon said casing, an abrasive wheel rotatably supported within and upon said head and having a conical end face defining a sharpening surface, and rotatable about an axis substantially aligned with the axis of said output shaft, means coupling said output shaft and abrasive wheel for conjoint rotation, said head including means locating drill bits with their cutting lips in stationary sharpening engagement with said sharpening surface, electric switch means for said motor, said switch means being disposed within said casing and including an electrically insulating operator accessible from outside said casing.

DETAILED DESCRIPTION Referring now more specifically to the drawings, a drill sharpener embodying the present invention is illustrated generally at 11 in FIG. 1 and is seen to include a motor housing 13 enclosing an electric motor 14. The motor housing 13 is disposed within a pair of telescoped insulating

members

15, 16 which together form an insulating casing for the motor housing 13. The motor housing 13 is seated within an insulating baffle 17 fixed to the casing member 16 by screws 18, and has an end bell 26 which bottoms against ribs 19 formed on the casing member 16. The casing member 15 is secured to the casing member 16 by long screws 21 and has bosses 23 which bear axially against the upper end of the motor housing 13. Heads 25 of motor housing screws are received in openings 27 in bosses 23 for location and stability of the parts. In addition, a resilient member 28 between the bottom of casing 16 and the end bell 26 to hold the upper part of the motor housing 13 against the bosses 23.

The motor 14 includes a rotatable armature 29 which drives an output shaft 31 through a transmission located within a gear case 33. Electric power for the motor 14 is supplied from a source through a line cord 35 which extends into the casing member 16 and is supported by a strain relief 34. The line cord 35 includes a pair of

conductors

36, 38 which are connected to a slider switch 37 and the motor 14. Another conductor 32 connects the slider switch 37 to the motor 14. Another slider 39, constructed of an electrically insulating material, is interconnected with the slider 37 and has a finger portion 40 disposed exteriorly of the casing member 16 for operator control of the motor 14.

Casing member 15 does not enclose any live electric parts and may be made from relatively inexpensive electrically insulating material such as for example, Acrylonitrile-Butadiene-Styrene (ABS). CYCOLAC manufactured by Marbon Chemical, Division of Borg- Warner Corp., is a suitable material. The casing member 16 and the baffle 17 enclose live electric parts and for double insulation purposes, are formed from an electrically insulating, self-extinguishing, relatively high temperature resistant material such as, for example, a phenylene oxide. NORYU, manufactured by General Electric Co., is one example. Thus, the

conductors

32, 36 are disposed in a way defined by a dependent skirt 46 and a plurality of lugs 50 along one side of the baffle 17, and a plurality of upstanding lugs 48 on the casing member 16, (see FIG. 4). The conductor 38 is disposed in a way defined by a dependent skirt 44 and a lug 52 along the other side of the baffle 17, and an upstanding lug 54 on the casing 16. This construction insures that the

conductors

32, 36, 38 cannot reach any of several air inlet slots 56 in the casing member 16 should these conductors break anywhere along their length. The spaced arrangement of the

lugs

48, 50 and the relatively small lugs 52, 54 allows adequate cooling air to flow around

skirts

46, 44 and circulate into motor housing 13.

A drill bit sharpener head 42 includes a cast metal body 41 removably secured to the insulating casing member 15 by screws 43. A spindle 45 is rotatably supported within the body 41 by bushing 47 and has an abrasive grinding wheel 49 secured thereto by a nut 51. The body 41 has a plurality of generally parallel openings 53 of different sizes formed therethrough which align with a conical sharpening surface 55 of the wheel 45. in use, a drill bit to be sharpened is inserted through a suitably sized opening 53 and pressed against the surface 55 of rotating wheel 45.

The drill bits are angularly located for proper sharpening in the openings 53 by means of a plate 57 which has apertures generally aligned with openings 53 and shaped to engage at least one of the flutes in the drill bits. This plate 57 may be angularly adjustable about the spindle 45 by means of an eccentric knob 59 rotatably supported upon the body 41. However, this construction forms no part of the invention and is not described further here. For a detailed explanation thereof, reference may be made, however, to the copending application of S. G. Enders, Ser. No. 17,109, filed March 6, I970, and owned by the assignee of the present application.

According to an important feature of this invention the motor driven shaft 31 is interconnected with the spindle 45 by a novel coupling 61 which serves to electrically insulate the latter from the former and compensates for small tolerance variations and misalignment thercbctwecn. This coupling 61 is constructed from a relatively strong, rigid non-conductive material. Glass reinforced ZYTEL", manufactured by E. l. Dupont de Nemours and Co., Inc., is satisfactory. This coupling 61 includes a first, generally cylindrical portion 63 threaded into shaft 31, and a second cup shaped portion 65 fitted over nut 51. The internal configuration of cup-shaped portion 65 is generally complimentary to but slightly larger than nut 51. Thus, rotation is transmitted from shaft 31 to nut 51 and spindle 45 through the coupling 61. By means of the slightly larger size of the portion 65 relative to the nut 51, small tolerance variations between and misalignment of the shaft 31 and spindle 45 is accommodated. However, the lower end of the spindle 45 is hollow and fits over a cylindrical projection 66 formed integral with he coupling 61 to help align the spindle 45 and the shaft 31.

Further, the non-conductive nature of the coupling 61 electrically insulates the spindle 45 from shaft 31. This together with the non-conductive nature of the

casing members

15, 16, baffle 17, and slider 39 renders the entire sharpener l 1 double insulated and safe to the operator even if the functional insulation in the motor 14 and housing 13 breaks down.

By the foregoing, there has been disclosed a novel double insulated drill bit sharpener and coupling calculated to fulfill the inventive objects set forth, and while a preferred form of the invention has been illustrated and described in detail, various additions, substitutions, modifications and omissions may be made thereto without departing from the spirit of the invention.

lclaim:

l. A drill sharpener including a casing, an electric motor supported within said casing and having an output rotary shaft, a sharpener head fixed to said casing, said head having a spindle rotatably supported thereon, an abrasive sharpening wheel fixed to said spindle, a torque transmitting coupling having one end thereof formed of hollow, cup-shaped configuration and loosely and non-rotatably receiving one end of said spindle, said coupling having its other end threaded into said shaft, whereby to electrically insulate said shaft from said spindle and accommodate small tolerance variations and misalignment therebetween.

2. A drill bit sharpener comprising a motor housing having an electric motor therein, an electrically insulating casing including first and second telescoped members enclosing said motor housing, a baffle fixed within one of said casing members and supporting said motor, said baffle being constructed of electrically insulating material and cooperating with said one casing member whereby to retain electric conductor means in place within said one casing member, a sharpener head including a body fixed to said casing and having a spindle rotatably supported thereon, an abrasive wheel fixed to said spindle, said motor having a rotatable output shaft, and insulating means coupling said motor shaft to said spindle.

3. A drill sharpener comprising an electrically insulating casing, an electric motor supported within said casing and having an output shaft, a sharpener head fixedly supported upon said casing, an abrasive wheel encased within and rotatably supported upon said head and coupled to said shaft, said abrasive wheel having a conical end face defining a sharpening surface, said head having means thereon to guide and support selected sized drill bits with their cutting lips in stationary sharpening engagement with said sharpening surface.

4. A drill bit sharpener ad defined in claim 3 which includes means electrically insulating said motor from said sharpening head.

5. A drill sharpener as defined in claim 4 wherein said insulating means includes an insulating coupling interconnecting said shaft and a spindle to which said abrasive wheel is fixed.

6. A drill sharpener as defined in claim 3 wherein said casing includes a pair of telescopic members axially trapping said motor therebetween.

7. A drill sharpener as defined in claim 6 which includes a baffle fixed to one of said members and laterally supporting said motor.

8. A drill sharpener as defined in claim 3, wherein said casing includes separable, electrically insulating members enclosing said motor, a line cord extending from said casing for connecting said motor to an electric source, electrical switch means on said casing, electrical conductors within said casing and connecting said motor, said switch, and said line cord, said casing members defining a wireway confining said conductors.

9. A drill sharpener comprising an electric motor enclosed in a housing, said motor having transmission means within said housing and an output shaft accessible from outside said housing, an electrically insulating casing substantially completely enclosing and trapping said housing therein, a sharpener head fixedly supported upon said casing, an abrasive wheel rotatably supported within and upon said head and having a conical end face defining a sharpening rotatable about an axis substantially aligned with the axis of said output shaft, means coupling said output shaft and said abrasive wheel for conjoint rotation, said head including means locating drill bits with their cutting lips in stationary sharpening engagement with said sharpening surface, electric switch means for said motor, said switch means being disposed within said casing and including an electrically insulating operator accessible from outside said casing.

10. A drill sharpener as defined in claim 1 wherein said coupling has a cylindrical projection in said cupshaped end adapted to fit into said one end of said spindle, whereby to help align said spindle and said shaft.

Claims

1. A drill sharpener including a casing, an electric motor supported within said casing and having an output rotary shaft, a sharpener head fixed to said casing, said head having a spindle rotatably supported thereon, an abrasive sharpening wheel fixed to said spindle, a torque transmitting coupling having one end thereof formed of hollow, cup-shaped configuration and loosely and non-rotatably receiving one end of said spindle, said coupling having its other end threaded into said shaft, whereby to electrically insulate said shaft from said spindle and accommodate small tolerance variations and misalignment therebetween.

10. A drill sharpener as defined in claim 1 wherein said coupling has a cylindrical projection in said cup-shaped end adapted to fit into said one end of said spindle, whereby to help align said spindle and said shaft.