US2222580A - Grinding machine - Google Patents

Description

1940- J. v. BERGFELDT GRINDING MACHINE Filed July 27, 1958 4 Sheet s-Sheet 1 JUL/Us Vfizzearapr Nov. 19, 1940.

J. v. BERGFELDT 2,222,580

GRINDING MACHINE Filed July 27, 1938 4 Sheets-Sheet 4 Patented Nov. 19, 1940 UNITED. STATES PATENT OFFICE GRINDING MACHINE Julius V. Bergfeldt, New Britain, Conn.

Application July 27, 1938, Serial No. 221,499

4 Claims. (Cl. 51134) The present inventionrelates to .grinding niachines and more particularly to a grinder having a plurality of work holding chucks rotatably carried past one or more grinding wheels.

The object of the present invention is an improved machine of the above-indicated type wherein there is provided a rotating work table having a plurality of work holding chucks thereon and one or more grinding wheels located above the work table and adapted to surface grind the work carried in the chucks.

A still further object is a grinding machine having improved means for maintaining the grinding surfaces of the wheels sized and dressed without interruption in the operation of the machine.

A still further object is-a machine having improved means for feeding the grinding wheels toward the work and including means for controlling such feed in timed relationship to the rotation of the feed table.

A still further object is a machine wherein the speed of the grinding wheels may be varied and including improved variable driving means.

Other objects will be in part obvious and in part pointed out more in detail hereinafter.

The invention accordingly consists in the features of construction, combination of elements, and arrangement of parts which will .be exemplifled in the construction hereafter set forth and the scope of the application of which will be indicated in the appended claims.

In the accompanying drawings:

Figure 1 is a front view of a machine embodying the invention herein;

Fig. 2 is a plan view of Fig. 1;

Fig. 3 is a detail view of the manual and automatic means for feeding the grinding wheel shafts;

Fig. 4 is a sectional view on the line 4--4 of Fig. 3;

Fig. 5 is a view partially in section of the variable driving means;

Fig. 6 is a sectional view of the variable drive pulley assembly;

Fig. '7 is a fragmentary sectional view of a grinding wheel shaft and the feeding spindle therefor; and

Fig. 8 is a detail view of the variable drive supporting bracket.

Referring to the drawings, the machine includes a cylindrical supporting base III in which there is centrally located a shaft l2 on which is mounted a rotatable work holding table M, the diameter of which is somewhat less than the di ameter of the supporting base It. Intermediate of the periphery I! of the work supporting table I4 and the periphery ll of the base In, the base is provided with a horizontally arranged outer top plate l6 and an inner top plate l8; the inner top plate being spaced below the outer plate l6 by a vertically arranged shoulder 20. The work holding table I4 is adapted to be rotated about the shaft I! by any suitable variable drive mechanism which may be located in the base 10, which drive mechanism has been omitted for purpose of simplicity. V

The work table carries a plurality of work holding chucks 22 which have been shown more or less diagrammatically and are provided with suitable jaws adapted to be closed for a portion of rotation of the table and opened during the remainder of the rotation to allow the work pieces to be readily removed therefrom and new work pieces placed therein. The jaws of each chuck are automatically opened and closed by a plunger 24 provided on its outer end with a roller or follower 26 which is spring pressed into engagement with the vertical surface of the shoulder 20 during the angle of rotation in which the jaws are open and adapted to receive the work holding pieces. The follower is adapted to ride over a cam 28 arranged on the shoulder 20 for urging the plunger inwardly to close the jaws during the angle of rotation in which the work pieces must be securely held.

Th work pieces are thus rotated beneath s'uitable grinding wheels 30 which are vertically carried on a support 32 which extends upwardly from the top plate It and carries a substantially triangular shaped housing 34, which housing overhangs the inner top plate l8 of the base It) and the work holding chucks of the rotatable table i l, with the apex of the housing being closest to the center shaft I2, as viewed in Fig. 2. The sides 36 and 38 of the housing are arranged at right angles to one another, and each side makes an angle of with a diameter extending through the center of the shaft l2 and the apex of the housing.

The housing provides a duplex support for the grinding wheels 30 and their associated driving mechanism, and inasmuch as the construction of each is identical, only one will be described, with like numbers applied to the other. As best seen from Figs. 4 and 5, there is mounted on each side wall 36, by suitable bolts 40, a vertically arranged base plate 42. The upper portion of the base plate 42 has secured thereon an upper spindle housing 44 and shaft housing 46. The

lower portion of the base plate 42 has bolted thereon suitable ways 48 in which there are slidably mounted a lower spindle housing 50 and shaft housing 62. The uI-per and lower shaft housings 46 and 52 are provided with aligned bores for receiving a grinding wheel shaft which is provided on its lower end with a grinding wheel supporting plate 56 on which the grinding wheel 30 may be secured in any suitable way.

The portion of the shaft 54 which is positioned in the lower shaft housing 52 isprovided with upper and lower threaded portions 58 (the upper end being shown in Fig. 7) the threaded portions being adapted to receive a securing nut 60 adapted to position therebetween suitable upper and lower ball bearing races 62 and a spacing sleeve 64. Positioned between the nut 60 and the top plate of the housing 52 there may be provided any suitable spacer 66 to cause simultaneous vertical movement of the housing 52 and the shaft 54 for raising and lowering the drive shaft and grinding wheel, as hereinafter explained.

The drive shaft 54 extends above the housing 52 and into a sleeve 68 rotatably mounted in the upper shaft housing 46; the shaft being suitably keyed in the sleeve to permit vertical movement relative thereto. The upper end of the sleeve 68 extends above the housing 46 and has secured thereon a drive pulley 10 having atop and bottom groove therein. The pulley 10 connects through suitable driving belts I2 and I4 to a pair of pulleys "Sand 18 arranged on the upper end of an intermediate driving member the lower end thereof carrying a pair of pulleys 82 and 84, which in turn connect through suitable belts 86 and 88 to a pulley mounted for rotation on a shaft 92 of a drive motor 94.

As may best be seen in Fig. 2, the motor 94 is mounted on a wall 06 extending at right angles to the wall 36 of the housing 34, and the intermediate driving member 80 is adjustably mounted on a bracket 98, which bracket is secured to a wall I00 positioned within the housing 34. The intermediate driving member 80 may be adjusted to vary the speed of the grinding wheel 30, and to accomplish this the member 80 comprises a center shaft I02 rotatably supported in a bracket I04, which bracket is provided with a shoe I06 mounted for slidable movement in the ways I08 of the supporting bracket 98. The ways I08 are arranged at an angle of 15 to the horizontal, whereupon movement of the bracket I04 will move the shaft I02 transversely of the wall I00. In order to transmit the angular movement of the member I02, the various driving pulleys and driving belts heretofore mentioned are provided with cooperating grooves and drive surfaces, all of which taper at an angle of 15 to the horizontal.

The upper and lower sets of pulleys on the shaft I02 each comprises independent cooperating members adapted to be moved toward and away from one another and are so arranged that upon transverse movement of the shaft I02 the upper and lower pulleys will open out or close in in opposed relationship to one another (see Fig. 6). To accomplish this, the upper member IIO of the pulley 16 is spaced from the upper member I I2 of the pulley I8 by a sleeve I I4; the pulley members I I0 and I I2 being mounted on a reduced portion II6 of the shaft I02, with the pulley member II2 abutting against the upwardly facing shoulder I I8 intermediate of the enlarged and reduced portions of the shaft I02. The lower member I20 of the pulley I6 is mounted on the outer surface of the sleeve 4 and connects through suitable bolts I22 which extend through the member II2 to the lower member I24 of the pulley I8; the member I24 being mounted on the outer surface of a sleeve I26 which is rotatably mounted in the bracket I04 and in which the shaft I02 may be moved vertically.

The lower set of pulleys 82 and 34 are similarly constructed and corresponding parts have been correspondingly numbered, with the suffix a" added thereto. With this arrangement, the pulley members I24 and I24a are spaced apart at a fixed distance by the sleeve I26 and the interposed ball bearing races I28, and upon adjustment of the bracket I04 the members I24 and I240, will be moved transversely and simultaneously raised or lowered, depending upon the direction of movement of the bracket. Thus if the bracket I04 is moved to the left, as viewed in Fig. 6, the members I24 and I24a will be raised and will simultaneously cause the members I20 and I20a, which are connected thereto, to be raised. As the tapered surfaces of these members ride over the tapered surfaces of the connecting belts, the shaft I02 will be drawn downwardly, thus causing the members of the upper set of pulleys I6 and 18 to close in and the members of the lower sets of pulleys to open out, thus changing the position of the belts on the driving surfaces and varying the speed from the motor 54 to the pulley I0.

The bracket I04 may be adjusted to adjust the variable stepless pulleys by a suitable threaded stem I30 which extends into a threaded opening therein and projects outwardly therefrom and through a sleeve I32 in the rear wall I34 of the housing 34; the stem being prevented from longitudinal movement in the'sleeve by a suitable collar I36 and the manually operable handle I38. Thus it will be seen that the speed variation of the grinding wheel has an infinite range which not only permits the variation of the speed of any one grinding wheel, but allows the use of various sizes of grinding wheels on the same drive shaft.

There is also provided means for lowering and raising the grinding wheel towards and from the work holding pieces, and to accomplish this there is mounted in the upper spindle housing 44 the reduced upper end of a spindle I40 (see Fig. '7) which extends through a suitable bore I42 and is secured in place by a nut I44 and held against rotation by a key I46. The spindle extends down and through an aligned bore in the lower spindle housing 50, which housing has rotatably mounted therein a sleeve I48 correspondingly threaded to and adapted to be rotated on the spindle I40.

The lower end of the sleeve I48 terminates in a bevel gear I50 which cooperates with a bevel gear I52 secured on the inner end of a control shaft I54 (see 'Fig. 4), which shaft extends through and out of the shaft housing 52 and has secured on its outer end a suitable manually operable control wheel I56. Upon rotation of the wheel I56, the shaft I54 will rotate gear I52 to cause rotation of the bevel gear I50 and the sleeve I48, whereupon the sleeve I48 will move vertically on the spindle I40 to move the shaft housing 52 and grinding wheel shaft 54 up or down, depending upon the rotation of the control wheel, and thus adjust the grinding wheel relative to the work pieces.

As it is desirable to automatically lower the grinding wheel 30 towards the work pieces, there is positioned intermediate of the shaft housing 52 7 and the manual control wheel I56 a ratchet wheel I58 which is secured in any suitable way to a sleeve I60 splined onto the shaft I54 for simultaneous rotation therewith. The wheel I58 is en- .closed in a housing I62 having mounted therein a ratchet dog I64 which is normally spring pressed into engagement with the ratchet wheel I58 and may be cammed out of engagement therewith by a manually operable lever I66 when it is desired to manually operate the shaft I54 and raise or lower the housing.

The housing I62 is mounted for rotation about the shaft I54 and sleeve I60 and is provided with a rearwardly extending link I68 which connects to the depending lever I10 of a solenoid I12. The weight of the solenoid and the connecting linkage I68 and I10 is such as to normally rotate the housing I62 in a clockwise direction, as viewed in Fig. 3, to position the ratchet dog I64 under one of the teeth of the ratchet wheel I58. The

housing I62 is also provided with a laterally ex-- movement of the housing I 62 and thus vary the number of teeth over which the ratchet dog I64 rides and control the amount of feed of the grinding wheel.

The solenoid I12 is normally de-energized (see Fig. 3) and becomes energized upon the closing of a suitable switch mounted on the outer plate I6 of the base I0 (see Fig. 2) which switch I86 is periodically actuated by a cam member I90 carried on a supporting plate I92 secured to the rotatable work holding table I4. Upon closure of the switch I88, the solenoid I12 will become energized (through suitable connections not shown) to rotate the housing I62 in a counterclockwise direction, whereupon the dog I 64 will rotate the ratchet wheel I58 to rotate shaft I54 and lower the grinding wheel 30 a predetermined amount, depending upon the setting of stops I18 and I80. Upon the automatic opening of switch I88, the solenoid will become de-energized, and the weight of the associated linkage as heretofore described will rotate the housing clockwise to position the dog I64 for the next lowering operation.

Another improvement in the presentgrinding machine is the provision of means for sizing and dressing the grinding wheels 30 at predetermined times during the revolution of the table I4. In the embodiment illustrated, the wheels are adapted to be sized and dressed once during each revolution, and to accomplish this there is provided a pair of spaced apart diamonds I64 and I96 vertically arranged on the supporting plate I92. As

beneath the roughing wheel and will engage same intermediate of the center and the outer periphery'thereoi', and thus in sizing and dressing of the wheel it will do so without hollowing out or giving the wheel a concave surface. 5 The diamond I96'is so spaced from the diamond I84 that it will pass inwardly of the roughing wheel. However, upon further rotation of the table, the diamond I96 will engage the finishing wheel intermediate of the center and the inside periphery thereof; whereas the diamond I94 will clear the finishing wheel. It will be noted that the supporting plate I92 is positioned just ahead of the first open chuck into which anew piece of work has been placed. Upon rotation of the table, the cam I90 will cause the grinding wheel to be lowered immediately after the last piece of work has been ground by the wheel and immediately before the sizing and dressing diamond I84 contacts the wheel. Thus when the wheel engages the next piece of work, it will be properly sized and dressed to rough grind the work a predetermined amount. Upon further rotation, the cam I90 will engage the second switch I88 to lower the finish grinding wheel into position to be operated upon by the finishing diamond I96.

It is apparent that if the type of work is such that more than one sizing and dressing of the wheels is required, a plurality of supporting plates and diamonds could be positioned around the periphery of the rotating table I4. As it is sometimes desirable to arrange the lower surface of the grinding wheels oil? the horizontal, the base plate 42 (see Fig. 5) is provided with an adjustment stud I08, which stud may be screwed in against the wall surface 36 to tilt the supporting plate 42. Inasmuch as the amount of tilt in grinding work is only a matter of thousandths, the required amount may be accomplished without disturbing the securing hold of 40 the bolts 40.

From the foregoing, the operation of the machine appears abvious; it being apparent that once, the machine is placed in operation and properly adjusted for the particular type of 45 work to be ground the entire operation there after will be automatic.

As many changes could be made in the above construction and many apparently widely difierent embodiments of this invention could be made 'without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. 55

It is also to be understood that the language used in the following claims is intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention which, as a matter of 60 language, might be said to fall therebetween.

I claim as my invention:

1. In a machine of the character described, a rotatable work holding table, a pair of grinding wheels supported above said table, each of said 65 grinding wheels having a fiat radial grinding surface facing the work holding table, a pair of sizing and dressing means carried by said table,

rotatable work holding table, a pair of grinding wheels supported above said table, each of said grinding wheels having a flat radial grinding surface facing the work holding table, one of said grinding wheels being at a greater radius from the center than the other, a pair of sizing and dressing means carried by said table, one of said sizing and dressing means being at a greater radius from the center than the other and adapted to size and dress the radial surface of the grinding wheel at the greater distance from the center and clear the wheel at lesser distance, said other sizing and dressing means being adapted to size and dress the radial surface of the other grinding wheel and clear the wheel at greater distance.

3. In a machine of the character described, a rotatable work holding table, a grinding wheel positioned above said table, ratchet means for feeding said grinding wheel towards said table, a solenoid adapted to actuate said ratchet means. and a switch adapted upon being closed to energize said solenoid, and means carried by said table for periodically closing said switch.

4. In a machine of the character described, a rotatable work holding table, a plurality of work holding chucks carried by said table, sizing and dressing means carried by said table intermediate ot a pair of said work holding chucks, a grinding wheel supported above said table, means for feeding said grinding wheel toward said table, and means carried by said table intermediate 0! a work holding chuck and said sizing and dressing means for actuating said grinding wheel feeding means, whereby said wheel will be sized and dressed intermediate or the passage 01 two of said work holding chucks.

JULIUS V. BERGFELDT.

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