US2970407A - Drill point grinding machine - Google Patents

Description

Feb. 7, 1961 J. H. PASELL DRILL POINT GRINDING MACHINE Filed Feb. 10, 1959 FIG- 2 2 Sheets-Sheet 1 im' fw,

INVENT R JOSEPH H PASELI- BY www /nLcMMV lATTORNEYS y Feb. 7, 1961 J, H, PASELL 2,970,407

DRILL POINT GRINDING MACHINE BY mf ATTORN EYS Umm States! P C Norman Industries, line., Springfield, Mass.,-acorpora tion of Massachusetts Filed Feb. 1o, 19s9, ser. Np. 792,363 *s Claims. orsi-iss) -This invention relates to lg'rindiiu'gmachine particularly, to machines for Igrinding "the point ends of twist drills.

In grinding machines of the type "referred tofitis faconventional practice to providea drill holderada'pted present the point ends of drills to a radialfsu'rfalce'of `a grinding wheel for v'grinding ai'i'd sharpening vends. During the grinding ope tion, 'the may maintain a xed position loft el drillpointor 1 move the drill s o that the positionof its point is "adj a predetermined manner vvrel'a'ti'\ 'fe "to the radial surf of the grinding wheel. 'In either event wear on he Esurface of the 'grinding wheel occ i ticular annular area rand after `th d-rills have been ground, it is necessaryftod 'surface of the wheel in order that the po ceeding drills vmay be accurately n d.

It is the general object of the present 'vide a drill point grinding machire Vdft eabbv m type wherein provision is made for oscillating'th g wheel in a radial planeduring grinding operai' so that wear is distributed over 'thefradialsurf e"o'f tli'e grinding wheel with the result that 'lessfre'uentdissing y-of the wheel isrequired.

The drawings showa preferred embodiment@ the'invention and such embodiment will be described, Alit will be understood that varioscli'angesm'ay he fromfthe construction disclosed, and that imthejdr nds olf fsuc# `Vand description are not to be construed 'as'deiinin or limiting the s cope of the inventiomthecla'irirs f gr a part of this specification being "relied upon `forth'a't purpose.

chine taken along the :line A3,-"3 ii'rF-ig. '2,

Fig. 4 is an enlarged fragrieta'r'yse'c'tiorial viw tv'k'h along the line {tf-4 in Fig. 3.

Referring particularly to Figs. lgad3 of the drawings, it willbe observed ythatthe `grinding machine shownihereiny includes la grinding wheel V1 0 of vco rivention al construc tion and whichhas a radial'griiiding surface o l'face 12.

There is also included in the grinding machine "5a drill coiivleftional type. A general -A:description of `the*"said holder is therefore adequate `for fa hfull iiiidrsfandingof the invention.

Tli efar'effour principalcorripqnentsof holder j114; *iraniel 'a "cylindril v'slide 16 `whichE-constitutes the maiden-forbid 2,979,407 Patented Feb. 7, 19,61

main 'supporting member o-f the holder, a swivel head I18 carried by a projecting. end portion of the slide 16, 'a

swivel member 20 which is supported by the swivel head l1 8 and which may be swiveled or oscillate'd about Vthe 5 axis thereof, and a drill supporting lmember 22 mounted on 'the swivel member 20 for movement therewith and "adaptedto hold a drill with its point end in engagement with the radial surface 12 of the grinding whe'el 10 and with its axis inclined upwardly and rearwardly toward said surface. Y v

A block 24 'supported in a ii'xed position lbelow vthe grinding wheel 1t) is provided with a suitable bore 2S 4for receivingand supporting a rearportion of 'the Vcylindrical normal to the plane of the radial surface '12 of the *grinding wheel. A handwlieel 26 .is associated with suitable lbinder means for'securing the slide 24 in an adjusted position in the bore 25 whereby to establish a desired horizontalpositionofthe drill and drill holder vcomponents ca'rriedlby saidslide relative tothe radial surface '126i the wheel '10. T he swivel 'head 18 is supported'on the projecting end portion of :the slide 16 below and frwardly of the grinding wheel l@ with its axis inclined'rearw'ardly from the vertical toward the radial surface 120i `saidwheel a's best illustrated in Fig. 3.` The swivelineinjber20 'maybe secured in an adjusted position lalorig'tlie axis of the swivel headlS by means ofa suitable sleeve 2'] and the drill supporting member 22 is adaptedjfor 'movement relative to the swivel member Ztl toward -and away from the radial"surface i2 of :the Wheel il). The member '22'may bejsecured in an adjusted position relative to said swivel member 20 bym'eans 'of a binder screw "28. `Means Vfor supporting drills in lposition jfor grinding "on the member 22 comprise a VLShaped forward support ymember '3d provided with astop orrest 32 for engaging 'thelips at the point ends of the drills, a V-shaped rear support rnemberd, and a springioperated plunger 36`fo`r urging the drills forwardly into engagement with the-stop or 'rest 32. I During the grindingl and Asharpening operationen the pointend of a drill, the' machine operator holds the drill in position in'the supports Sil and 34 and 'manually oscilllates the swivel member 20 whereby to oscillate thefdrill Ysupporting member 22 and the drill so that the point end thereof is vmoved back and forth approximately along a horizontal radius of the grinding wheel lit. After one vlip of the drill point end has been ground to the desired `rconfiguration, ythe drill is reversed for grinding of the 4'other lip ina similar'manner. Obviously, as a result of such grinding operation, wear occurs on the radial surface 12 of the grinding wheel 10 throughout. a particular fann'ular area, the location and width of which Lareais determined by the aforesaid 'generally radial' travel ofthe ldrill point across said surface. In order that such wear rnay not result in inaccuratelyv ground drill points, it is necessary to dress the'radial surface of the grinding wheel 10 at rather frequent intervals. The description which follows is'directed to theniainportion of the grinding "machine shown in the drawings and, more` particularly, to the y'means provided therein for supporting and driving the grinding wliecl "16. As will be seen, the said means, 4` in v"fulfillmentfof/the aforementioned general "object tif the invention, vpryidesf'fo-r yoscilla-tion of the grinding wheel 1'0'1'11 a radial plane ,during grinding operations 65 thereonand'as aresult'wear is ldistributedover the radial "grinding-surface of the wheel and less frequent 4dressing of `the`surfaceis required.

ys'f'bestillustrated in Figs. 2 and 3 o-f'thedrawingafa 70 main'frarn'eiand housing member of the'grindingmachir'ie li cated generally by the reference numeral 3S cornprises erilatlb"ase vplate iil :and a'poitin d2 'which "exteiids slide '16 zwith the slid'eaxi's extendinghorizontally arid *aard-tor vertically upwardly from the base plate 40. The base plate 4t) may be secured to a fion-r or othersupporting surface by means of suitable bolts 44, 44 and the said plate has two parallel forwardly and rearwardly extending s lots. 46, 46 formed therein. The purpose of Ythe slots 46, 46 will be set forth hereinafter.

The upwardly extending portion 42 of the main frame is shown as being generally U-shaped when viewed from above, but the detailed configuration of said frame portion is subject to wide variation within the scope of the invention. ln the form shown, the frame portion 42 serves as a first part of the grinding machine housing. More specifically, the said frame portion constitutes the front and side walls of a lower part of the machine houslng. i

VA flat horizontally disposed plate 48 located at the upper end of the frame portion 42 constitutes a third portion of the main machine frame and housing member 38. As best illustrated in Fig. 2, a U-shaped slot 50 extends forwardly and rearwardly in a central portion of the plate 48. As shown the plate 48 is formed integrally with the frame portion 42 and said portion 42 is formed inte-f grally with the base plate 48 as in a cast construction. Obviously, the main frame and housing member 38 may be formed alternatively of several welded or bolted together parts.

The drill holder 14 is supported in operative position by the main frame and housing member 38 of the grinding machine. As shown, a fiat horizontally disposed plate 52 provided with a U-shaped slot 54 is secured to the upper surface of the plate 48 of the main frame 38 by means of suitable bolts 56, 56. The slot 54 extends forwardly and rearwardly in a central portion of the plate, 52 and aligns vertically with the slot S8 in the plate 48 when said two plates are secured together. A trough 58 for collecting coolant from the grinding wheel is welded or otherwise secured to the forward end portion of the plate 52 and the block 24 which supports the cylindrical slide 16 of the drill holder 14 is disposed within the trough 58 at a rear portion thereof. The block 24 is rigidly secured to said trough as by suitable welding and additional support for said trough and block is provided by suitable bolts 68, 68 (one shown). The bolts 60, 60 extend through the main frame plate 48 and the base of the trough 58 and are threadedly entered in the base portion of the block 24.

In accordance with the invention, a vertically elongated secondary frame member indicated generaly at 62 is supported between upper and lower end portions 64 and 66 thereof by the main frame 38 for oscillation in a vertical plane. As shown, the secondary frame member 62 extends vertically through the slots 50 and 54 in the plates 48 and 52 and is journaled approximately at its center on a stud 68 which projects horizontally from a block 70. The stud 68 is shown as being formed integrally with the block 70 and said block is in turn formed integrally with the main frame 38 at an upper portion of said frame. The secondary frame member 62 is secured against axial movement along the stud 68 by a cap 72 and a bolt 74 which extends through said cap and into a suitably threaded opening in the projecting end surface of said stud.

In further accord with the present invention, the grinding wheel 10 is supported at the upper portion 64 of the secondary frame member 62 for rotation about a horizontal axis with its radial surface 12 lying in a plane parallel to the plane of oscillation of said frame member. As shown, the grinding wheel 10 is fixedly secured to a front end portionof a spindle 76 supported in a bearing housing 78 with its axis normal to the plane of oscillation of the frame member 62. .The bearing housing 78 encloses suitable ball bearing units (not shown) within which the spindle 76 is rotatably supported.

The housing 78 is fixedly secured within a suitable bore 80 which is formed in the upper portion 64 ofthe frame member 62 and which extends through a forwardly projecting bos's'SZ formed at said upper portion of the frame member. A forwardly facing cup-shaped cover 84 for the grinding wheel 10 is secured to the front end portion of the boss 82 and secured in turn to said cover at its open end is a guard 86. As best illustrated in Fig. 1, the guard 86 is suitably formed to permit the necessary movement of a drill and the drill supporting member 22 of the drill holder 14 relative to the radial surface of the grinding wheel 10. A conventional wheel dressing device 88 fxedly secured to the guard S6 forms no part of the present invention and is therefore not described in detail.

From the foregoing it will be apparent that the secondary frame member 62 can be oscillated in a vertical plane about the stud 68 to oscillate the grinding wheel 10 in a radial plane as desired to distribute wear thereover. The wheel cover 84, the guard 86, and the dresser 88 all supported by the boss 82 will, of course, be oscillated with the said frame member and grinding Wheel.

In order to prevent dust from the grinding wheel and other foreign matter from passing rearwardly in the machine to the area around the frame member 62 where other machine components yet to be described are located, the grinding machine is provided with additional housing means comprising a second or upper housing part indicated generally at 90. The housing part 90 cooperates with the aforesaid main frame 38 or first housing part of the machine and a rear housing cover plate 92 to enclose the area surrounding the frame member 62 and said other machine components and prevent dust and the like from entering said area.

A first section 94 of the second housing part 90 which may be formed of sheet metal or the like is shaped along its lower edges to overlap the plate S2 and to join tightly with the upper side edge portions of the upright portion 42 of the main frame 38. Suitable bolts 96, 96 (Fig. 2) secure the said housing section to the plate 52. A forwardly projecting portion of the housing section 94 encloses the boss 82 on the frame member 62, the grinding wheel 10, and a rear portion of the grinding wheel cover 84. A front cover plate 98 secured to the front end of said projecting portion of the housing section 94 is provided with a circular side opening 100 (Fig. l) and the front portion of the wheel cover 84, the grinding wheel guard 86, and the wheel dresser 88 are located approximately inl said side opening. The said opening 100 is slightly larger in diameter than the grinding wheel cover 84 and guard 86 to allow for oscillation of said guard with the grinding wheel 10.

A liange 102 extending around the first section 94 of the housing part 90 at a rear edge portion thereof is provided with a plurality of small threaded receptacles 104, 104. The rear housing cover plate 92 is secured in position (Fig. 3) by a plurality of screws 106, 106, some of which are entered in the threaded receptacles 104, 104 and others of which are entered in suitably threaded openings 105, 105 formed in the rear surfaces of the main frame or first housing part 38.

A second section of the upper housing part 90 comprises a vertical bulkhead 108 which is disposed within the first housing section 94 adjacent the side opening 100 and which separates the space Within the forwardly projecting portion of said housing section from the remaining space therewithin. The boss 82 on the frame member 62 and the spindle therewithin projects forwardly or outwardly through ka circular opening 110 (Fig. 2) in the bulkhead 108 which opening is of suficient diameter to allow for oscillation of said boss and spindle therewithin. On the front or outer side of the bulkhead 108 there is secured by means of suitable bolts 112, 112, a mounting plate 114 for a flexible bellows like dust cap 116. The dust cap 116 has its rear or inner edge portion tightly secured to the mounting plate 114 andextends forwardly therefrom about the boss 82.

t its front or outer edge :portion the dust cap V116 is tightly' secured to the boss 82 by `meaiis of a riiigy 118 and 'thus serves cooperativelyrwiththe bulkhead 108 to prevent grinding dust and other foreign matter within the forwardly projecting, portion of the housing section 94 from entering the area around the frame member 4zurearwardly of the bulkhead 108.

The necessary power for driving the grinding wheel and for oscillating the frame member 62 is provided by an electric motor 12() mounted on the lower portion 66y of said frame member. As shown, the motor 120 is secured to the frame member 62 by means of suitable bolts 122, 1-22 yand projects forwardly from the lower portion 66 of said member. The output shaft of the motor 121) extends horizontally and rearwardly through a suitable aperture 124 in said lower portion of the framemember. Said output shaft is connected in driving rela'- tion with the grinding wheel spindle 76 by rst power transmitting means and second power transmitting means, also supplied with power by said electric motor, drives a means for oscillating the secondary frame member 62.

As shown, rst and second pulleys 126 and 128 areV ixedly mounted on a rear end portion of the grinding wheel spindle 76. A third pulley 130 xedly mounted on the output shaft of the motor 120 is connected with the rst pulley 126 by a belt 132 which is preferably of the V-type. A second belt 134 also preferably of the V-type connects the second pulley 128 with a fourth pulley 136. The fourth pulley 136 drives the aforesaid means for imparting oscillatory motion to the secondary frame member 62, which meansiwill now be described. A

The fourth pulley 136 is xedly mounted on the hori'- zontally extending -input shaft of aV speed reducer 138.

The speed reducer v138 is secured by suitable bolts 140 to a bracket 142 which is in turn ysecured lto the lower portion 66 of the frame member 62 by means of bolts 144, 144. The -output shaft of the speed reducer 138 extends horizontally in alignment with-the input shaft thereof and has xedly mounted thereon a cam means. Said cam means may take the form of an eccentric, a disc type cam or other similar devices. As shown, said means comprises a disc type cam 146 which is rotated by the speed reducer in Contact with a cam engaging member secured against horizontal movement, said cam engaging member being shown as comprising a roller 148 mounted on the previously mentioned b-lock 70.

From the foregoing it will be seen that with a suitable contour provided on the cam 146 (Fig. 4), rotation of said cam 146 in engagement with the roller 148 will impart oscillatory movement to the secondary frame member 62 whereby to oscillate the grinding wheel 10 in the desired manner and distribute wear on the radial surface thereof. While the travel of the grinding wheel is subject to wide variation within the scope of the invention, it is presently contemplated that the cam will be shaped to provide for oscillation of the grinding wheel through a distance of approximately one-eighth of an inch. Similarly, provision is made for a frequency of oscillation of the grinding wheel substantially less than the speed of rotation of the wheel, but a wide range of frequencies of oscillation may be provided for within the scope of the invention.

There is also included in the grinding machine means for supplying a` coolant to the grinding wheel during grinding operations, but said means is incidental only to the present invention and therefore requires only a general description. A storage and settling tank 150 forming a part of the coolant system in the machine is mounted on wheels 152, 152. Said wheels are located in the aforementioned slots 46, 46 in the base plate 40 of the main frame and convenient removal of the tank from the mach-ine is thereby provided for. supply hose 154 connected with a pump 156 extends A coolant i oscillating means.

upwardly and then forwardly in the grinding machine 'to -valve 15S disposed infront of the housing cover plate 98. From the valve 158 coolant is supplied through auconduit 160 to a suitable nozzle (not shown) which directs arstream of the coolant toward the grinding surface of the wheel 10. Return of the coolant to the storage tank 150 is providedfor by a drain conduit for pipe 162 which is connected to a lower portion of the coolant collecting trough 58.

vFrom the foregoing it will be apparent that a drill point grinding machine particularly adapted to promote uniform wear on the radial grinding surface of its grinding wheel has been provided. While the principal advantage of the machine has been set forth above and need not be repeated here, some less apparent advantages of the machine shouldbe mentioned. As a result of mounting the drive motor for the grindlng'wheel Aand the oscillating means on the oscillating frame member; littleor no difficulty is encountered in effecting a driving relation between said motor and the grinding wheel and rfhat is, the difficulty of maintaining' ay desired tension of the drive belts which is encountered in lan arrangement where the drive motor is xedly mounted independently of the oscillating frame lmember is avoided. A lsimilar advantage. obtains with respect` to the driving connection between the motor and the means for oscillating the secondary frame member. In addition, the drive motor may serve as a means for bal'- ancing the weight of the grinding wheel and its associated parts'about the axis of osciliation of the secondary frame member. This will permitV theA oscillatory movement of therframe' member to be more accurately controlled' and will serveto reduce or eliminate vibrations which might cause inaccuracies; in the finished drillV points.

The invention claimed is:

l. In` ardrill grinding" machine of the type which in cludes a drillholder adapted to present the point ends of twist drills or the like to the radial surface of a grindmg wheel for grinding of the same, the combination comprisingv a main frame, a vertically elongated secondary frame member supported between its upper and lower endportions by the main frame for oscillation in a vertical plane, agrinding wheel having a radial grind# ingfsurface supported at the upper en`d portion of said secondary frame member for rotation about a horizontal axis normal to the plane of oscillation of said secondary frame member, an electric motor mounted on the lower end portion of said secondary frame member, first power transmitting means connecting the output shaft of said electric motor in driving relation with said grinding wheel, and means for oscillating said secondary frame member in said vertical plane whereby to oscillate said grinding wheel radially during grinding operations and distribute wear on the radial grinding surface thereof, said last mentioned means comprising cam means supportedv by said secondary frame member for rotation about a horizontal axis and operatively associated with a cam engaging member supported and secured against horizontal movement by said main frame and also comprising second power transmitting means driven by said electric motor and speed reducing means on said secondary frame member operated by said power transmitting means and rotatably driving said cam means.

2. In a drill grinding machine of the type which includes a drill holder adapted to present the point ends of twist drills or the like to the radialsurface of a grinding wheel for grinding of the same, the combination comprising a main frame, a horizontally projecting stud supported at an upper portion of the main frame, a vertically elongated secondary frame member journaled between its upper and lower end portions on said stud for yoscillation in a vertical plane, a grinding wheel spindle rotatably supported at the upper end portion of said secondary frame member with its axis extending horizontally and normal to the plane of oscillation of said frame member, a grinding wheel having'a radial grinding surface iixedly mounted on a front end portion ofrsaid spindle, first and second pulleys lixedly mounted on a rear end portion of said spindle, an electric motor iixedly mounted on the lower end portion of said secondary frame member with its output shaft extending horizontally, a third pulley xedly mounted on the output shaft of said motor, iirst belt means connecting said third pulley in driving relationship with said first pulley, a speed reducer xedly mounted at the lower portion of said secondary frame member with its input and output shafts extending horizontally, a fourth pulley fixedly mounted on the input shaft of said speed reducer, second belt means connecting said second pulley in driving relationship with said fourth pulley, a cam engaging member supported and secured against horizontal movement by. said main frame adjacent the output shaft of said speed reducer7 and a cam means iixedly mounted on the output shaft of said speed reducer and adapted to contact said cam engaging means during rotation whereby to impart oscillatory motion to said secondary frame member, the aforesaid grinding wheel thus being oscillated radially during grinding operations to distribute wear over the radial grinding surface thereof.

3. In a drill grinding machine of the type which includes a drill holder adapted to present the point ends of twist drills or the like to the radial surface of a grinding wheel for grinding of the same, the combination comprising a main frame and housing member, additional means cooperating with said main frame and housing member to form a machine housing which has a side opening in its upper end portion but which is otherwise closed, a vertical bulkhead having an opening therethrough disposed in an upper portion of the machine housing adjacent said side opening, a horizontally projecting stud supported within the machine housing by an upper portion of said main frame and housing member,'a vertically elongated secondary frame member in the housing iournaled between its upper and lower end portions on said stud for oscillation in a vertical plane, 40

a horizontal grinding wheel spindle rotatably supported at the upper end portion of said secondary frame member with a front end portion thereof projecting outwardly through the opening in said bulkhead, a grinding wheel having a radial grinding surface tixedly mounted on'said projecting front end portion of said spindle and located approximately in said housing opening so that its vvsaid radial face is accessible from outside the housing, a ilexible dustcap having inner and outer ends connected lre1- 'spectively to'said vertical bulkhead and said grinding lwheel spindle between said bulkhead and grinding wheel, the `portion of said spindle which extends from the bulkhead to the outer end of said dust cap being surrounded by said cap and said bulkhead and dust `cap serving cooperatively to prevent the entry of grinding dust to the interior of the machine housing inwardly of the bulkhead', irst and second pulleys fixedly mounted within themachine housing on a rear end portion of said spindle, an electric motor iixedly mounted in the housing on the lower end portion of said secondary frame member with its output shaft extending horizontally, a third pulley xedly mounted in the housing on the output shaft of sad motor, rst belt means connecting said third pulley in driving relationship with said rst pulley, a speed reducer fixedly mounted in the machine housing at the lower portion of said secondary frame member with its input and output shafts extending horizontally, a fourth pulley fixedly mounted on the input shaft of said speed reducer, second belt means connecting said second pulley in driving relationship with said fourth pulley, a cam engaging member within the machine housing supported and secured against horizontal movement by said main frame and housing member adjacent the output shaft of said speed reducer, and a cam means ixedly mounted on the output shaft of said speed reducer and adapted to contact said cam engaging means during rotation whereby to impart oscillatory motion to said secondary frame member, the aforesaid grinding wheel thus being oscillated radially during grinding operations to distribute Wear over the radial grinding surface thereof.

References Cited in the tile of this patent UNITED STATES PATENTS 966,732 Brinkmann Aug. 9, 1910 2,382,256 Radu Aug. 14, 1945 2,471,443 Munro May 31, 1949 2,544,604 Mader Mar. 6, 1951

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