US1981445A - Cutter salvage machine - Google Patents

Description

Nov. 20, 1934. F. J. AKER 1,981,445

I I CUTTER SALVAGE MACHINE Filed Jan. 18, 1932 3 Sheets-Sheet l INVENTOR F. 7. A/fE/F ATTORNEYS Nov. 20, 1934. F. J. AKER v CUTTER SALVAGE MACHINE Filed Jan. 18, 1932 5 Sheets-Sheet 2 INVENTOR E1 A/(EF ATTORNEY 5 Nov. 20, 1934. F. J. AKER CUTTER SALVAGE MACHINE 5 Sheets-Sheei 5 Filed Jan. 18, 1932 ATTORNEYb variety of grinding operations.

Patented Nov. 20, 1934 PATENT OFFICE CUTTER SALVAGE MACHINE.

Floyd J. Aker, Newark, N. J assignor to Eastern Cutter. Salvage Corporation, a corporation of New Jersey Application January 18, 1932. Serial Nb. 587,224

3 Claims.

This invention relates to a machine for grinding cutting tools such as end mills, side mills, angle cutters, counter bores and the like and relates more particularly to a machine for practicing a method of grinding and equalizing the space between the teeth of cutters as set forth in my copending application Serial No. 587,223 filed January 18, 1932 for Method of grinding cutters.

The operation of salvaging a cutter involves not only the removal of material to shape new teeth but in shaping the teeth so that the grinding operation serves to equalize or accurately space the teeth and furthermore the grinding must be accomplished at relatively high speed and at low cost.

Machines have heretofore been used to salvage cutters and such machines were constructed along the lines of machines employed for a Such machines as commonly constructed could be used to regrind a cutter but inasmuch as these machines were made to meet the requirements of other grinding operations they did not have an arrangement of cooperating elements capable of meeting the demands encountered when an efiicient salvaging operation was required.

If a salvaging operation is to'be profitable it must be accomplished in such manner that the cost thereof does not too closely approach the selling price of a new tool. 7

Cutting tools being made of high speed steel are extremely hard and are ordinarily diflicult to grind and when ground on the usual or-standard type of grinders the operation is unsatisfactory for the following reasons:

First, the machines are so constructed that relatively light cuts are taken usually of a maximum depth of .002 to .003 of an inch since the construction of the machine is such that the movement of the work moved for a grinding operation, is positive and not under the control of the operator. By reason of, this construction a heavy cut is prohibitive in'that it would result in over-heating of the tool causing it to lose its temper or in scorching the surface.

Second, the position of the operator with relation to the work is such that he has no opportunity of observing the degree of out being taken and must depend upon the machine.

Third, it has been found that when grinding cutters to obtain the best result it is essential that the operator practice the grinding operation in such manner that he is able not only to observe the cut being taken but is. able to feelor sense the degree of out which is not possible with machines as heretofore employed.

Fourth, although it is well recognized that it is common practice to provide slip clutches for various mechanisms it is importantthat the driven, grinding wheel slips when too heavy a cut is taken and that the operator be able, when too heavy a-cut' is taken, to easily and quickly adjust the relation of the wheel and cutter which was not possible with machines as heretofore constructed. V

An object of, the present invention is therefore; to provide a, grinding machine which, when in the hands of anoperatorwill have the necessary flexibility to permit him, without the exercise of any unusual skill, to practice a, method; of eco-. nomically and expeditiously grinding cutters.

,Another object of the invention is to provide a cutter grinding machine-in which the powerful grinding force of a rotating abrasive elementmay be employed in much the same manner as a hand carving tool except that in the present case theoperator need only control the work being performed.

Another object. of the invention is to provide an eflicientgrinding' device wherein speed and accuracy are attainable in the absence of skilled labor or costly and complicated mechanisms.

Other objects and advantages of the invention will bev readily'understood by reference to the accompanying drawings. in which Fig. 1 is a front elevational view of a machine embodying the present invention showing a cutter supporting mechanism in vertical cross section;

Fig. 2 is. a side elevational view of the machine shown in Fig. 1;

Fig. 3 is a horizontal sectional view on lines III-III in Fig; 1;

Fig. 4 is a view of the cutter and its support taken on linesIV-IV in Fig; 2;

Fig. 5 is a fragmentary view showing a portion of .a worn cutter with a grinding wheel for making the initial slots;

Fig.6 is a view similar to Fig. 5 but showing a grinding wheel. for performing the roughing cut on the teeth; 1

Fig. '7 is another fragmentary viewsimilar to Fig. 6 but showing a wheel for finishing the teeth. 7

A machine constructed in accordance with the present invention may comprise a supporting frame 10 having a suitable foot piece 11 and an upper bearing bracket 12. The frame 10 is provided with a; carrier 13 including a threaded taken cal slot 15 in the frame 10.

"be slidable directly on the arbor.

extension 14 extending through a suitable verti- A vertical screw 16 extends through the threaded portion of extension 14 and the lower end of the screw is provided with a bearing pin 17 rotatable in a boss 18, the upper end of the screw extends through with a slidable carriage 25 movable on guides 26, 26 andis provided with a nut 2'7 on an extension 28. A screw 29 passes through the nut and one end of the screw is journaled at 31 in the carriage 13. The opposite end of the screw is rotatable in'a bear ing 32 and is provided with a hand crank '33.

A manipulation of the crank 33 serves to move the carriage 25 forward and backward in relation to the frame 10. Thecarriage 25 is pro vided with a U-shaped support member 34 having a bolt 35 extending through its base pertion 36. Thehead of the bolt is disposed in a slot 37 in the carriage 25' so that'the member '34- may be moved relative to the carriage and held in position by tightening the bolt 35. The

upper'or exposed end of the bolt 35 is provided with anut 38. Thus whenthe nut38 is "loosened the'supp0'rt member may be adjusted and when 41 having split bearings 42 and 43 respectively to receive a rod orarbor 44. The bearings 42 and 43 are adjustable by means ofsuitable screws 45 so that the arbor may readily be slid into position and clamped. This arbor serves asa guide to direct a cutter or other workpart to be ground through a rectilinear path. "If desirable a cutter or work partto be ground may be mounted directlyon the arbor andthe arbor may be adjusted in'the' bearings 42mm 43 and the bearings clamped sufficiently to hold the arbor but permit it to be slid forward and backward to carry the work'part or the cutter may It is preferableyhowever, to mount a work part as for example a cutter 46 on a sleeve 47 as shown in the drawings. x I

As shown more clearly in. Fig. '4 the sleeve, 47 may beoff'sufiicient length to accommodate cutters of various lengths and spacer members 47 may be employed to clamp the cutter between a shoulder48" and a nut 50'which threadedly H engages one end of the sleeve. 1

A guide piece'or finger 51 isprovide'd'toengage atooth of the cutter to hold it against rotation during a' grinding operation and as will be noted from'the drawings-the position of the I grinding wheel with respect to the axis of roin a slot 53. in the arm 52. When the bolt is loosened the finger may be moved in a straight line within the limits of the slot and may also be moved through an arcuate path about the bolt which serves as a pivot.

The arm 52' is secured to the base 36 of the support 34 by a tap bolt'54' which may be manipulated to permit an adjustment of the arm and the finger 51' mounted thereon. By reason of the adjustability of the finger and its support, the finger maybe set to angles of the teeth of cutters of various types.

When the finger 51' is adjusted the cutter may be moved back and forth by means of a hand piece The cutter is allowed sufficient movement along the arbor to permit it to clear a grinding wheel 52 and the finger 55 at which time the operator rotates the cutter to bring another tooth in position to be ground and an causes excessive strain which ordinarily results in mis-alignment of the shaft 49 or rapid wear resulting in chattering.

m the construction shown this disadvantage is overcome by providing a tapered bearing 53 (see "Fig. 3) and a hardened center bearing 54 for the shaft 49 which latter bearing is engaged by a' hardened center point 55 disposed in an adjustable support56. The support 56 is provided with a split collar 57 clamped to: a support rod 57' secured to the bracket 12. The shaft 49 is provided with a pulley 58 driven by a belt 59 from anys'uitable source of power (not shown). By reason of the construction including the tapered bearing 53 and center bearing 54 rotatable about the center 55 it is possible to run the grinding wheel to take heavy cuts without the rapid wear which would otherwise occur. The tapered bearing 53 which is a bushing is provided with a'take up nut 61 so that the bushing may be adjusted to maintain its running fit when worn. A pair of lock nuts 62 on threaded portion 63 of the shaft 49 serve to secure the shaft to the bushing 53 for rotation therewith.

The present machine is useful for the convenient grinding of cutters by following any chosen method but is especially advantageous when practicing the method set forth in the above mentioned copending application. When practicing this method a cutter having any number of teeth may be mounted on'the arbor 44. The

teeth of cutter to be reformed may have been worn down as shown at 60 in Fig. 5 leaving slots or notches 61'. The sides 62' or faces of the worn-teeth are taken as the starting surface for the space equalizing process during grinding.

I The first grinding operation is preferably performed with a gashing or narrow saucer wheel 63 which is used to form slots 64 to a depth selected for the equalizing operation. The finger 51" is set to engage a tooth which is spaced from the tooth being ground by a plurality of teeth. On a ten tooth cutter it has been found desirable to set the finger three spaces or teeth from the face inoperative relation to the grinding wheel. The finger is then adjusted to engage a tooth and the hand wheel 24 and hand crank 33 are manipulated to bring the tooth to be ground-in such relation to the grinding wheel that a relatively heavy out will be taken when the cutter is moved along the arbor. 1

The grinding wheel rotates in the direction of the arrow X or in a counter-clockwise direction. The wheel is coarse grained and of a diameter of about eight inches and about one quarter of an inch wide. It will be noted that the grinding wheel 52 is positioned off center with respect to the axis of rotation of the cutter so that when the wheel engages the cutter for a grinding operation it serves to hold the tooth in firm engagement with the finger.

The pulley 58 on the shaft 49 is preferably 2% inches in diameter and the belt 59 is of leather and is preferably 2 inches wide. The shaft is rotated at a speed of about 1750 to 2300 R. P. M. By reason of the relation of the pulley and belt friction ratio the operator is prevented from taking too deep a out since if the cut is too heavy the belt will slip.

Having set the cutter for a selected cut it is drawn toward the operator who is positioned in front of the machine and as indicated in Fig. 2 has a line of sight along the tooth being ground. As he pulls the cutter toward him he is able to observe the grinding operation and at the same time feel the character of the cut.

When the face of the initial tooth has been ground he moves the cutter to a rear position so that the teeth clear the wheel and finger and rotates the cutter in the direction of the arrow Y or toward the finger and engages the next tooth with the finger so that the cutter is in position to have another tooth face ground adjacent to the first ground tooth. This operation is repeated until a ground tooth reaches the finger. When this occurs the operator, by reason of the present construction, may start to cut and will be able to feel and observe that the cut is too deep since the cut on the tooth which would engage the wheel will be twice as heavy as the previous cut. The operator then moves the cutter by manipulating hand crank 33 to change the space relation between the finger and the wheel bringing them closer together considering the distance as measured around the pitch circumferential line of the teeth. This adjustment is so made that the next tooth is given a very slight cut and by reason of the novel arrangement of the operating elements of the machine the operator is easily and quickly able to make the proper adjustment. The slight cut is then taken from all the teeth except the teeth which have been given the heavy out since the faces of these teeth will have in effect retreated and will pass free of the grinding wheel.

When the grinding wheel no longer cuts material from the teeth the wheel and finger are again adjusted so that another slight cut is taken.

This operation is repeated until the faces of the initially cut teeth begin to approach the grinding element. The operator at all times has the teeth under observation and as the wheel and finger begin to reach an adjustment which will bring them a distance apart which is nearing a space equal to a given number of equal parts of the pitch circumference of the cutter, the operator by exercising reasonable care can find this distance which becomes accurate as the initially ground teeth begin to have material removed by the grinding wheel.

During the main grinding operation the space between the grinding wheel and the initially ground teeth is plainly visible to the operator and serves to indicate the approach of the necessary determined spacing between the grinding wheel a distance equal to one or more equal parts of" the circumference depending upon how many teeth happen to be in the cutter subjected to the grinding operation and according to the number of teeth the wheel is spaced from the finger.

When the faces 62 have been equalized the gashing wheel 63' may be operated to cut the. slots 64 to the proper depth or the slots may be out to the proper depth during the equalizing operation.

A roughing wheel 65 as shown in Fig. 6 is then used to rough out the teethtaking off a portion, leaving teeth 66 to be finished.

A finishing wheel 67 as shown in Fig. '7 is then used. This wheel has a curved surface and finishes teeth as indicated at 68.

It will be evident that since the first operation equalizes the spaces the roughing and finishing operations may be performed with very little attention on the part of the operator. The result- I ant teeth will be of equal width as well as accurately spaced since the operation of equalizing the teeth merely shifts the position of the teeth about the axis of the cutter. The actual positions of the teeth change, but their spacing and Width are held uniform.

It may happen that a cutter may be received on which one or more teeth are out of spaced relation to an excessive degree and in practice therefor it may be desirable to first check for such abnormal variations. When the cutter is mounted on the arbor and the finger engages a tooth the grinding wheel may be moved so that it is in close relation to the face of a tooth. By reason of the present arrangement of parts in the machine the operator is able to quickly and conveniently observe the degree of space between the wheel and the surface to be ground.

With the wheel in close proximity to the surface of one tooth the operator proceeds to bring the teeth progressively to position adjacent to the wheel. As each tooth is positioned a variation in the space between wheel and tooth face will be apparent since as above set forth the operator is so positioned as to have a line of sight along the teeth and he may make an adjustment bringing the wheel and faces in such relation as to take off the high spots or to trim the faces of the teeth as a preliminary step in practicing the present method. The variations in the teeth may be very small and the trimming operation may not be necessary. It will be evident, however, that ordinarily with the usual method of grinding, slight inaccuracies would be built up whereas with the present method they are corrected.

Although the above description includes the use of the gashing wheel to perform the equalizing operation it is evident that the roughing wheel or the finishing wheel may be used for this purpose. In practice, however, it has been found preferable to equalize the spacing of the teeth when cutting the slots or gashing.

With the above description in mind the importance of the present invention will be evident and it will be appreciated that by reason of the present arrangement of the parts, their adjustability and the ease with which they may be controlled it is possible for an unskilled operator to produce a precision product at relatively high speed.

The present mechanism makes it possible for an operator to perform grinding operations on extremely hard material such as high speed steel with substantially the same ease and accuracy as would attend the cutting of soft or annealed metal.

Although a preferred embodiment of the invention is shown and described herein, it is to be when said cutter is movedby means of said hand arbor, a holder for supporting said arbor be-' neath said wheel, means for slidably mounting a cutter on said arbor, a hand piece for moving said cutter on the arbor, means for adjusting said arbor to position said cutter for a tooth grinding operation when said cutter is moved, by means of said hand piece and means mounted on said holder for engaging a tooth of said wheel during a grinding operation.-

3. A machine for grinding the faces of cutter teeth comprising a rotatablegrinding wheel, an arbor, a holder for supporting said arbor beneath said wheel, means for slidably mounting a cutter on said arbor, a hand piece for moving said cutter on the arbor, means'for adjusting said arbor to position said cutter for a tooth grinding operation when said cutter is moved by means of said hand piece and means mounted on said holder for engaging a tooth of said wheel during a grinding operation and means for adjusting said holder relative to said wheel. I

FLOYDJ. AKER.

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