US1500122A

US1500122A - Grinding machine

Info

Publication number: US1500122A
Application number: US138913A
Authority: US
Inventors: Alfred B Fowler
Original assignee: United Shoe Machinery Corp
Current assignee: United Shoe Machinery Corp
Priority date: 1916-12-26
Filing date: 1916-12-26
Publication date: 1924-07-08
Anticipated expiration: 1941-07-08

Description

July 8, 1924. 1,500,122

2A. B. FOWLER GRINDING mourns Filed Dec. 26 1916 6 Sheets-Shut 1 July 8, 1924. 1,500,122

A. B. FOWLER GRINDING MACHINE Filed Dec. 26. 1916 6 Sheets-She'd, 2

I 204 14a 60 I76 I42 F 1g. 2. 1a

July 8 1924.

1,500,122 A. B. FOWLER GRINDING MACHINE Filed Dec. 26 1916 6 Sheets-Sheet 3 A. B. FOWLER GRINDING MACHINE Filed Dec. 26 1916 6 Sheets-Sheet A P. PPS-b 6 w om, a .x/ 4

July 8, 1924.

1,500,122 A. s. FOWLER GRINDING MACHINE Filed Dec. 25. 1916 6 Shuts-Sheet 5 July 8, 1924. 1,500,122

A. B. FOWLER omunmu gmuma F1106 Dec. 25, 1916 a sna s-s eet a 40 64 a? 6 as M ii 100 10 Fig. 8.

Patented July 8, 1924.

UNITED STATES PATENT OFFICE.

ALFRED 1B. FOWLER, OF BEVERLY, MASSACHUSETTS, ASSIGNOR, BY MESNE ASSIGN- MENTS, TO UNITED SHOE MACHINERY CORPORATION, OF PATERSON, NEW JERSEY,

A CORPORATION OF NEW JERSEY.

GRINDING MACHINE.

Application filed. December 26, 1916. Serial No. 138,913.

To all whom it may concern:

Be it known that I, ALFRED B. FOWLER, a citizen of the United States, residin at Beverly, in the county of Essex and tate of Massachusetts, have invented certain Improvements in Grinding Machines, of which the following description, in connection with the accompanying drawings, is a specification, like reference characters on the drawings indicating like parts in the several figures.

This invention relates chin's and particularly to an automatic machine adapted for grinding curved knives having curved edges.

Curved blade or molded blade knives of the type illustrated in the patent to Noble No. 543.349 are commonly ground to have a curved edge of predetermined shape by being moved in a curved path relatively to the grinding Wheel. These knives are usually ground by hand and the skill of the Workman is depended upon to secure the desired curvature of the cutting edge as Well as the bevel thereof. Inasmuch as a plurality of such knives are commonly mounted in a single rotating cutter head. it is important that they shall be ground in such a fashion as to be of exactly the same Wright or length and that their cutting edges shall have the same curvature. Hand grinding has necessarily been slow and inaccurate, especially when a curved surface is operated on.

It is well understood that if a curved surface be cut by a plane surface at a fixed angle, the resulting curved line of intersection will have a fixed shape which may be calculated with certainty. It is accordingly proposed to grind a curved blade of the type specified in a plane surface cutting through the knife at such an angle as to give the desired edge bevel. If the cross-sectional contour of the blade has been properly designed. this manner of grinding Will give exactly the desired shape of the cutting edge.

hen a plurality of similar blades are similarly ground as described, uniformity in theedge bevel and in the shape of the cutting edge is secured.

The general object of this invention is to devise a grinding machine wherein blades of to glinding mathe type specified may be ground to give exactly the desired bevel and shape of edge. In its preferred form, the invention comprises a machine arranged to automatically grind at the same time a plurality of similar blades so that they will be exactly alike. The advantage of such a construction is exemplified by the common practice of mounting a plurality of similar blades in a common cutter head and by the necessity of having these blades uniformly ground in order to have them act uniformly on the Work.

One of the features of the invention relates to improved mechanism for setting or gaging the position of one or more blades in the machine so that they may be ground properly and, if more than one is being ground, equally. In another aspect, this invention comprises a novel machine for grinding the edges of a plurality of similarly curved or molded blade knives which are to be mounted in a common cutter head as previously described so as to secure uniformity in the bevel and shape of their cutting edges. and with the blades for a single cutter heath uniformity of length. This machine is characterized by means for positioning the curved blade or blades of a series of similar blades in uniform and determinate relation to the grinding plane of a grinding element and means for relatively traversing the blade and said grinding element at a uniform and predetermined angle calculated to cause said grinding element to cut through the knife blades at a uniform angle giving a desired and uniform edge bevel and cutting edge. lVhcn as is commonly the case, the blades are provided with grooves in their side edges with which positioning and holding tongues on the cutter head co-operate, similarly tongued blade clamping means may be, and as shown herein are utilized to position and hold the blades for grinding so that the blades when ground may be positioned in their cutter head with their cutting edges in proper and uniform rclation to the Work.

Another feature of the invention consists in an improved grinding machine arranged to operate automatically when set in motion to the end that the blades and grinding member may be given any desired number of relative traversing move ments. Associated with this feature is a novel arrangement for advancing the blades toward the grinding member as they are ground away, said means being dependent upon the relative traversing movements of the two with the ultimate result that the amount to be ground away is predetermined.

Still another feature of the invention lies in the novel arrangement of parts whereby the grinding member is oscillated along its axis of rotation during the grinding operation so that it will be worn away evenly.

A preferred form of the apparatus embodying my invention is described in the following specification and shown in the accompanying drawings in which,

Fig. 1 is an end elevation of the grind ing machine;

Fig. 2 is a front elevation;

Fig. 3 is a skeleton diagram showing the operating mechanism for effecting movement of the blade holding carriage an mechanism by which the grinder is oscillated along its axis of rotation;

Fig. 4 is a skeleton view showing the parts employed for controlling the operation of the grinding machine and determining the number of traversing movements of the blade holding carriage;

Fig. 5 is a detailed view of part of the apparatus shown in Fig. 4;

Fig. 6 is a detailed perspective, with parts broken away, showing the mechanism for advancing the blades toward the grinding member;

Fig. 7 is a detailed perspective of the knife gaging device together with the lock ing means therefor; and

Fig. Sis a vertical transverse section on the line 88 in Fig. 2.

Adjustably mounted upon the upper end of a supporting column 10 is atable 12 which is retained upon said column by means of bolts 14 passing through elongated slots 16. A bolt 18 screw-threaded in the table 12 rests upon an abutment 20 on the column and provides means for accurate vertical adjustment. of the table. Slidably mounted on this table and connected thereto by the dove-tailed connection 22 is a work carriage 24 upon which is mounted the blade holding means which will be later more fully described. A gage 26 (Fig. 2) is slidably mounted in a boss 28 upon the carriage 24 to assist in the adjustment of the table 12 relative to the grinding wheel. This gage is provided with a pin entering an open ended slot in the boss 28 and is normally held in inoperative position by a spring pulling the pin into the slot. "When ready to use the gage, the operator will pull the pin out of the slot and, giving the gage a partial turn, rest the pin on the top of the boss 28. The gage surface will then be brought against the grinding wheel by adjustment of the table thus enabiing adjustment to compensate for wear of the grinding wheel and to determine the bevel of the blades as will be later described.

A housing 30, bolted to the upper end of the supporting column, serves to support various operating parts and has journaled in its upper portion a shaft 32 upon which is mounted the grinding wheel 34. This grinding wheel is here shown as the well known disc type having a cylindrical grinding face. For the protection of the operator, the greater part of the wheel is covered by a hood 36 supported upon the housing 30. A driving pulley 38 is loosely mounted upon the shaft and provides means for connecting the machine to any suitable source of power. This pulley is rigidly connected to the inner part 40 of a friction clutch 41, which has an outer member 42 which is slidably connected to the shaft by a pin and groove connection (Fig. 8) so that it is 1'0- tatable therewith but movable lengthwise of the shaft. The two parts of the clutch are normally held in engagement by a spring 44 compressed between a collar 46 on the part 42 and a bracket 48 mounted upon the housing 30.

Slidably connected with the shaft 82 is a worm 50 which is held against lengthwise movement by engagement with the sides of an opening in the housing 30 but is rotated by the shaft by a. pin and groove connec tion (Fig. 8). This worm meshes with a gear 52 loosely mounted upon a horizontal shaft 54 journaled in said housing at approximately right angles to the shaft 32. A clutch 50 provides means for connecting the gear 52 to this shaft and may be of any convenient type but is preferably of the type frequently referred to as the Horton clutch. In this clutch rollers are provided between the driving and the driven members which are normally spring-pressed into position to connect said members for simultaneous rotation. They can, however, be rendered ineffective by engaging a projection 58 (Fig. 4) upon an external part of said clutch to hold the same stationary. Mounted upon the shaft 54 is a worm 60 engaging a gear 62 upon a vertical shaft 64 journaled in the housing 30.

The carriage 24 is provided with a rack 66 which is maintained in parallel relation to a fixed rack 68 upon the housing 30 and interposed between these racks is a pinion 70. This pinion is loosely pivoted on the end of an arm 7 2 which is oscillatable with a changing radius about a center determined. by a pivot post 71 jonrnaled in the housing. This arm 72 is actuated by a link connection 7a with a crank 78 upon the lower end of the vertical shaft 64. The arm 72 is slid-ably connected with the post Tet by means of a box 77 mounted upon the upper end of said post.

By means of the parts above described. the rotating movement of the power shaft 32 is transformed to a reciyn'ocating movement which is multiplied by the action of the pinion 70 between the

racks

66 and 68. This transforming means is also employed for oscillating the shaft along its longitudinal axis in order to oscillate the grinding member so as to cause the same to wear away evenly. For this purpose the ratchet 80 is loosely pivoted upon the upper side of the box 77 and is connected by a link with a lever 81 which is pivoted by a bolt 86 upon the bracket 18. The belt 86 is adjustable in a slot (not shown) in the bracket -18 in order to determine the length of the reciprocations of the shaft 32. The upper end of this lever is connected by means of a yoke 88 and sleeve 90 to the shaft 32 for oscillating the same. A springprcssed pawl 92 upon the. box 76 is oscillated by the movements of the arm 72 while a spring-pressed holding pawl 91 also engages the ratchet to prevent backward rotation thereof.

The action of the

clutches

41 and 56 is controlled by

rotatable cams

100 and 102 which are lined to a shaft 104 journaled in the housing 30. Iuterposed between the cam 100 and the clutch as is a bell crank lever 106 one end of which enters a depression in the cam surface when the same is in releasing position. as shown in Fig. 4. and allows its other end to engage the projection 58 on the clutch 56 thereby to disengage the gear 52 and the shaft 54-. Similarly the bell crank lever 108 is interposed between the can] 102 and the clutch -11 and has a forked end engaging the collar 46 on the clutch part 42. The other end of this lever engages a. projection on the cam surface when. the same is in its relea ing position. as shown in Fig. 1. thereby to move the clutch member 42 against the tension of the spring 14 out of engagement with the clutch part 40 which is secured to the driving pulley. This lever 1118 is pivoted on a. bracket formed on the housing flll and is provided with an operating handle 110 by means of which the driving pulley and the power shaft may be disengaged at the will of the operator regardless of the position of the cam 102.

Surrounding the shaft 10% is a spring 112. one end of which is fixed to the casing. This spring tends to rotate the shaft in a. clockwise dir ction when viewed from the front end as shown in Fig. --l'. The shaft 101 is held against rotation by a ratchet 114 mounted on the shaft. in connection with a spring-pressed holding pawl 116 mounted upon the casing. Associated with the ratchet 11st is a pawl 118 mounted upon an 104 in a counterclockwise direction against the tension of the spring 112 so as to bring the

cams

100 and 102 to the releasing position. shown in Fig. 1-. Vhen this position has been reached. the driving pulley will be disengaged from the power shaft and the operating connection between said shaft and the means for reciprocating the carriage 21 will be broken.

From the preceding discussion. it will be seen that. if the

pawls

116 and 118 are released at the beginning of the operation of the machine, to allow the; shaft 1.04 to rotate in a clockwise direction for a predetermined di tance. then the parts of clutches -11 and 56 will be thrown into engagement and a fixed number of traversing movements of the carriage 21 will rotate the shaft 101 far enough in a counter-clockwise direction to return the cams thereon to their releasing position. The position to which the cams and hence the shaft may be rotated by the spring 112, when the ratchet 114 is released, is detern'iined by the engagement of a projection .26 (Figs. 4 and 5) upon the cam 100 with an arm 128 loosely pivoted upon the shaft 104. The outer end of this arm 128 may be held in a predetermined angular position by securing the same by means of a nut 1230 to a slotted arcuate member 132 attached to the casing 30 (Fig.

1). A pointer 134 upon this arm may be provided for association with indications upon the member 132 which indications may conveniently represent the number of traversing movements of the carriage 24.

lyfovably mounted upon the carriage 24 is a. work plate or blade holder which is providcd with circular ribs engaging corre sponding curved ways or grooves 142 in the carriage. The curvature of these grooves is preferably concentric with .the curvature of the blade mounted in the holder in order that the curved blades may be moved around their own center of curvature when they are advanced toward the grinding wheel. The blade holder 140 is provided with a longitudinal groove 14-3 in which the

clamping devices

144 and 146 are mounted. Of these. the end clamps or blocks 144 are screw threaded to a rod 148 movable with the carriage and adapted to be operated by means of a hand wheel 150. The rod 148 is provided with right and left hand threads so that rotation of the same in one direction will bring the end clamps 144 together. Each of these clamping devices is provided with an overhanging lip, tongue shaped and adapted to engage a groove formed in the side of the blade to be ground, the members 146 each having a T-shaped head (see Fig. 2) providing tongues shaped to enter the grooves formed in the side edges of the blades and acting as spacers.

The blade holder 140 may be advanced toward the grinding wheel by a. screw 152 journaled in an ear on the carriage 24 and threaded in a nut 154 which is pivoted within an opening in the side of the clamp carrying plate or blade holder. Surrounding this screw is a spring 156 tending to turn the same in a direction to move the blade holder away from the grinding member. On one end of the screw 152 is a ratchet 158 held in one direction by a holding pawl 160 mounted in any convenient manner upon the carriage 24. Another spring-pressed pawl 162 is pivoted on one arm of a bell crank lever 164 which in turn is pivoted on the end of the screw-threaded rod 152 and spring-pressed in a clockwise direction. as viewed in Fig. 6, by a spring 166 against a stop 167. An ad justable stop 168 upon the table 12 is adapted to engage the lower arm of the bell crank lever 164 at the end of each reciprocation of the carriage thereby to cause movement of the ratchet 158 one step forward against the tension of the spring 156. A lever 170 pivoted on the carriage 24 is arranged with one end in operative relation to the

pawls

160 and 162. At the other end is a finger piece 172 and when this is depressed against the tension of the spring 174 the

pawls

160 and 162 will be released and the spring 156 will rotate the screw-threaded rod 152 so as to move the blade holder 140 away from the grinding wheel. A projection 176 upon one end of the rod 152 is adapted to engage a stop (Fig. 2) to limit the rotation of the rod 152 under the action of the spring 156 and define a starting point for the feeding movement of the blade holder.

In order to assist in setting the blades in the desired position in the blade holder. an arm 180 is pivoted to the carriage 24 and is provided at its upper end with a, bar 182 eonstituting an adjustable abutment adapted to engage the blunt or unsharpened end of each of the blades and move them to similar positions in the blade holder. The axle or rock rod 184 of the arm 180 is extended at one end and provided with a toe 186 adapted to engage and depress the finger piece 172 of the lever 170 when the bar 182 is brought into engagement with the ends of the blades.

A spring 188 surrounding the end of the axle 184 tends to turn the same so as to remove the bar 182 from engagement with the blades. Because of the pivotal mounting of the arm 180, the bar 182 will be movable to a plurality of positions parallel to the direction of reciprocation of the carriage 24. Further means is also provided for assisting in gaging the desired position of the blades in the blade holder and to this end a bracket 190 mounted upon the table 12 is grooved at its upper end for the reception of a sliding carrier 192 within which is adjustably mounted a finger or gage member 193 whose forward end is provided with an overhanging lip 194 adapted to enga e the bevel edge of one of the blades. In ad ition, a fiat resilient member 198 is mounted upon the gage 193 and arranged to engage the sharp edge of the adjacent blades and hold them against the bar 182. A rotatable cam 200 engaging projections upon the carrier 192 and mounted upon a rod 202 journaled in the bracket 190 is adapted to move the gage member toward and away from the blades so as to bring the same into and out of operative relation therewith. A knurled head 204: on the end of the rod 202 serves for rotating the same. Surrounding the rod 202 is a spring 206 tending to turn the rod and the cam 200 in a direction to urge the gage member to inoperative position. An adjusting screw 208 in the carrier 192 serves as a device for adjustably determining the operative position of the gage member 193 when it is moved forward against the tension of the spring 206. A forked piece 210 on the end of the rod 202 is adapted to receive. when in one position, a spring-pressed vertical bar 212 which is slidably mounted in the casing 30. Loosely pivoted within the casing 30 is a bell crank lever 21 1 one of whose arms is forked to engage a projection from the bar 212 in order to withdraw the same from engagement with the forked piece 210. The other arm of this lever is ofi'set so that it will be engaged by a starting lever 216 when the same is depressed against the tension of the spring 218 and will thereby withdraw the bar 212 from engagement with the forked piece 210 to allow the spring 206 to more the gage carrier 192 to inoperative position. The starting lever 216 is also provided with a cam 220 which is in operative relation (see Fig. 4) with the

pawls

116 and 118.

hen it is de ired to set the machine in operation. one or more blades will be inserted in the blade holder 140 and loosely engaged by the

clamps

144 and 146. It is assumed that the table 12 has already been adjusted according to the indication of the gage 26 to compensate for the wear of the grinding wheel and. at the same time, to determine the bevel at which the knives will be ground by placing the center of curvature of the groove 142 in the desired relation to the center of the grinding wheel. The gage member 194 may then be moved to its forward and operative position by-rolation of the cam 200 against the tension of the spring 206 until it is locked in this position by the vertical rod 212. The bar 182 will then be swung so as to bring the blunt ends of the various blades in alignment and at the same time to bring their sharp ends against the lip 194 and the resilient member 198. The blades may then be clamped. This movement of the arm 180 and its finger 186 will automatically depress the lever 1T0 thereby to release the pawls from the ratchet 158 and allow the spring 156 to rotate the screw-threaded rod 152 to a position determined by the projection 176. This action will move the blade holder 140 away from the grinding wheel. Supposing that the arm 128 (Fig. 4) has been s'et in the desired position thereby to determine the number of traversing movements of the carriage, the starting lever 216 may be depressed to unlock the gage member and at the same time to release the

pawls

116 and 118 from the ratchet 114. This will allow the spring 112 to rotate the

cams

100 and 102 until. they are stopped by the engagement of the projection 126 with the rod 128. This rotation will at the same time, by the action of bell crank levers 106 and 108, bring the

clutches

41 and 56 into engaging position thereby to connect the driving pulley 38 with the power shaft 32 and the power shaft with the traversing mechanism. The carriage 24 will then be reciprocated for the predetermined number of times as automatically determined by the action of the parts shown in Fig. 4 and the blade holder will at the same time be moved along the path determined by the grooves 142 to move forward the blades step by step as they are ground away. This determination of the number of traversing movements will obviously determine how much the blades will be ground At the same time, the grinding wheel will be reciprocated along its axis of rotation and the whole width of its grinding surface used.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. In a machine of the type described, a blade holder. a gage for determining the position of the blade in the holder, means for setting the machine in operation, and means responsive to the operation of the first mentioned means for causing the withdrawal of said gage to inoperative position.

2. In a machine of the type described, means for holding a plurality of blades in parallel positions, means for determining the position of one of said blades, and movable means adapted to be brou ht into operative relation with all of said blades for setting the remaining blades in accordance with the position of the first mentioned blade.

3. In a machine of the type described, a blade holder, a movable gage member for determining the position of the blade in said holder, means for moving said gage to operative position, and resilient means urging said gage to inoperative position.

4. In a machine of the type described, a blade holder, a movable gage member for determining the position of a blade in the holder, means for adjustably determining the operative position of said gage member, and resilient means for urging said gage member to inoperative position.

5. In a machine of the type described, a blade holder, a movable gage member for determining the position of a blade in the holder, resilient means for moving said gage member into inoperative position, locking means for retaining said moving means in one position, and means responsive to an operative condition of said machine for releasing said locking means.

6. In a machine of the type described. a blade holder, a movable gage member for determining the position of a blade in the holder, means for moving said gage memher into and out of operative position, resilient means urging the latter means to move the gage member out of operative position, means for locking said moving means in one position, a starting lever for said machine, means for operatively connecting said lever with said locking means so that when the machine is started the moving means will be released to allow the resilient means to move the gage member out of operative position.

7. In a machine of the type described, a blade holder arranged to hold a plurality of similar blades in parallel relation, a movable gage member adapted to be brought into operative relation with the cut-ting edge of one of said blades, and resilient means movable with said gage member and adapted to be associated with the cutting edges of the remaining blades to assist in clamping said blades in similar relation.

8. In a machine of the type described, a blade holder arranged to hold a plurality of similar blades in parallel relation, gaging means for definitely determining the position of the cutting edge of one of said blades, an adjustable abutment adapted to be brought into engagement with the blunt ends of said blades, and resilient means associated with said gaging means urging the remaining blades against said abutment.

0. In a machine of the type described, a blade holder arranged to hold a plurality of similar blades in parallel relation, movable means, one associated with one end of the blades and the other associated. with the other end of the blades to assist in setting the same in proper relation in the blade holding means, one of said means being adapted to assume a definite position.

10. In a machine of the type described, a grinding wheel, a movable carriage adapted. to be reciprocated with respect to said grinding wheel, blade holding means on said carriage adapted to clamp a plurality of blades in parallel relation, a movable gage adapted to assume a definite position andbe associated with one end of each of said blades to assist in setting the same in proper relation in the blade holding means. and means movable to a plurality of positions parallel to the direction of movement of said carriage and adapted to be brought into operative relation with the other ends of said blades to move the same against said gage member.

11. In a machine of the type described, a driven shaft, a grinding member mounted thereon, a blade-carrying carriage adapted to be reciprocated with relation to said grinding member, means including an oscillating arm for transforming the rotating movement of said shaft. into a reciprocating movement of said carriage, andmeans actuated by said oscillating arm for reciprocating said shaft along its longitudinal axis.

1:2. In a machine of. the type described, a rotatable grinding member, a blade carrying member, means comprising an oscillating arm for reciprocating the blade carrying member past the grinding member, a ratchet intermittently actuated by said oscillating arm, and connections from said ratchet to said grinding member for reciprocating said grinding member along its axis of rotation.

13. In a machine of the type described, a power shaft, a grinding member mounted thereon. a blade carrying carriage adapted to be reciprocated with relation to said grinding member, means for transforming the rotating movement of said shaft into a reciprocating movement of said carriage, and means actuated by said transforming means for oscillating said shaft along its longitudinal -axis.

14. In a machine of the type described, a power shaft, a grinding wheel mounted thereon, a blade carrying carriage adapted to be reciprocated with relation to said grinding member, means including a part mounted on said shaft for transforming the rotating movement of the shaft into the reciprocating movement of the carriage, means for imparting a rotating movement to said shaft from an external source of power including a clutch member mounted on said shaft, and means responsive to the reciprocations of said carriage for moving said shaft along its longitudinal axis without affecting the operation of the part mounted on the shaft.

15. In a machine of the type described, a grinding wheel and a blade holder mounted for relative traversing movement, and means responsive after a predetermined number of traversing movements for controlling the operation of the grinding member.

16. In a machine of the type described, a grinding Wheel and a blade holder mounted for relative traversing movement, means for eifecting said relative traversing movement, means responsive after a predetermined number of traversing movements for controlling the traversing operation, and. mechanism for varying said predetermined number of movements.

17. In a machine of the type described, a grinding wheel and a blade holding carriage adapted to be reciprocated relatively to one another, means including a clutch controlling the connection between a source of power and an operating part of the machine, and means including a pawl and ratchet adaptedsto be operated successively bv the reciprocating part for controlling said clutch after a plurality of reciproca tion.

18. In a machine of the type described, a grinding member and a blade holding carriage adapted to be reciprocated' relatively to one another, a clutch interposed between the source of power and an operating part ofsaid machine, a cam arranged in one position to operate said clutch to break the connection between the source of power and saidoperating part, means adapted when released to turn said cam by a predetermined amount relatively to said releasing position, and means responsive to the number of reciprocations for returning said cam to its releasing position.

19. In a machine ofthe type described, a grinding member and a blade holding member mounted. for relative traversing movement, rotatable means controlling said traversing movement, means for propelling the rotatable means in one direction, an adjustable stop associated with the rotatable means to limit its movement in this direction, means for adjustably fixing the position of said stop, and means responsive to the traversing movement of one of said members for moving said rotatable means away from said stop.

20. In a machine of the type described, a grinding member and a blade holding member adapted to be moved for relative trav' crsing movement, a clutch interposed between an external source of power and an operating part of said machine, rotatable means controlling said clutch, a stop associated With said rotatable means to limit its movement in one direction, and means responsive to the number of traversing movements for moving said rotatable means to its clutch releasing position.

21. In a machine of the type described. a rotatable grinding member and a blade holding member mounted for relative traversing movement, a power shaft for rotating said grinding member, a clutch for connecting a source of power to said power shaft, rotatable means arranged in one position to bring said clutch to releasing position, means including a starting lever for causing the rotation of said clutch controlling means away from releasing position, and means responsive to the number of traversing movements of one of said members for returning said clutch controlling means to releasing position.

22. In a machine of the type described, a rotatable grinding member and a blade holding member mounted or relative traversing movement, a power shaft for rotating said grinding member, mechanism for effecting the relative traversing movement, means including a clutch for connecting said power shaft to said traversing mechanism, rotatable means arranged in one position to bring said clutch to releasing position, means including a starting lever tor causing the rotation of said clutch controlling means away from releasing position, and means responsive to the number of traversing movements of one of said members "for returning said clutch controlling means to releasing position.

23. In a machine of the type described, a rotatable grinding member and a blade holding carriage mounted for relative traversing movement, a power shaft for rotating said grinding member, a clutch for connecting a source of: power to said power shaft, means, including a clutch, for connecting the power shaft to the carriage to reciprocate the latter. rotatable means arranged in one position to bring said clutches to releasing position, means including a starting lever for causing the rotation of said clutch controlling means away from the releasing position. and means responsive to the number of reciprocations of said carriage for returning said clutch controlling means to releasing position.

24. In a machine for grinding the edges of curved blades, a rotatable grinding memher and a blade supporting member mounted for relative traversing movement, and a blade holding means mounted upon said supporting member for movement on said supporting member in a circular path whose .enter of curvature substantially coincides with the center of curvature of said blades to feed th blades edgewise in an are.

25. In a machine of the type described, a grinding member, a carriage adapted to be reciprocated relatively to said grinding member, blade holding means mounted upon said carriage for movement in a curved path transversely to the direction of reciprocation of said carriage, and means responsive to the reciprocation of said carriage for controlling the movement of said blade holding means relatively to the carriage.

26. In a machine of the type described, a rotatable grinding wheel, a carriage mounted for traversing movement relatively to the grinding wheel, blade holding means mounted upon said carriage for movement in a direction to move the blade toward and away from the grinding wheel, means inclu ding a spring for moving said blade holding means to a predetermined position relatively to said carriage, and means responsive to the traversing movements of said carriage for moving said blade holding means against the tension of said spring to cause the blade to approach the grinding wheel.

2-7. In a machine of the type described, a grinding member, a carriage mounted for traversing movement relatively to the grind ing member, blade holding means movably mounted on said carriage to move the blade toward and away from the grinding member, means including a pawl and ratchet device for causing such relative movement, resilient means urging said blade holding means away from said grinding member, and means for releasing said pawl and ratchet to allow the operation of said resilient means.

28. In a machine of the type described, a rotatable grinding wheel, a carriage mounted for traversing movement relatively to the grinding wheel, blade holding means mounted upon said carriage for movement in a direction to move the blade toward and away from the grinding member, means including a spring for moving said blade holding means to a predetern'iined position relatively to said carriage, means for moving said blade holding means against the tension of said spring to cause the blade to approach the grinding wheel, normally inoperative means for rendering the latter means effective, a setting device adapted to be moved to bring the blade to the desired position before clamping the same in the blade holding means, and means responsive to the movement of said setting device to (narrative position adapted to actuate said normally inoperative means to cause the spring to become effective to move the blade holding means to its predetermined position.

29. In a machine of the type described, a rotatable grinding member, a carriage. mounted for traversing movement relatively to said grinding member. blade holding means mounted upon said carriage for movement to bring the blades toward or away from the grinding member, resilient means for urging said blade holding member in one direction, a pawl and ratchet device adapted to move said member in the opposite direction against the action of the resilient means,

'a blade setting device and connections between the latter and said pawl and ratchet device by movement of the blade setting device to operative position to allow the resilient means to become eifective.

30. In a machine of the type described, a support, a grinding member and a blade holding member mounted thereon, means for adjusting one of said members toward and away from the other to compensate for wear in the grinding member and to determine the bevel at which the blades Will be ground and a gage member associated with one of said members to aid in the relative adjustment thereof.

312 In a machine of the type described, a grinding element, means for simultaneously holding a plurality of similarly curved blade knives in uniform positions relatively to the acting portion of the grinding element, means for relatively traversing the blade holding means and the grinding element to grind the edges of the curved blades in a plane cutting through all the curved blades at a uniform angle, and means. actuated by the traversing movement for feeding the blades towards the grinding element in a path to maintain. the angle constant.

32. In a machine ofthe type described, a grinding element, means for simultaneously holding a plurality of similarly curved blade knives in uniform positions relatively to the acting portion of the grinding elc ment, means for relatively traversing the blade holding means and the grinding ele ment to grind the edges of the curved blades in a plane cutting through all the curved blades at a uniform angle, and means for feeding the blade holding means in a curve concentric With the center of curvature of the blades to maintain a uniform bevel while grinding.

33. In a machine for uniformly grinding the edges of a plurality of similar trans-- verselv curved blade knives to secure uniform edge bevels and cutting edges and uniform lengths, a grinding member, means for positioning the blades in uniform determinate relation to the acting portion of the grinding member, means for relatively traversing the blades and grinding member to grind the curved blades in a plane cutting all the blades at a uniform fixed angle, and means controlled by the traversing movement for uniformly limiting the depth of said cut.

34. A machine for grinding curved trimming blades having, in combination, a grind ing wheel, a blade holder, means for causing relative feeding movement of the holder and Wheel toward each other in a curve corresponding to the curvature of the blade, and means to cause relative movement of the Wheel and holder in another direction to grind the entire edge of the blade.

35. A machine for grinding curved trimming blades having, in combination, a grinding wheel, a work carriage movable across the acting portion of the grinding Wheel, a blade holder mounted on said. carriage, and means for feeding said holder in a curved path on the carriage.

S6. A, machine for grinding curved trimming blades having, in combination, a grinding wheel and a work carriage one of which is movable relatively to the other, a blade holder mounted in said carriage. and means for automatically feeding said holder in a curved path corresponding to the curve of a blade mounted in said holder.

37.111 a machine of the character described, a grinding Wheel, a carriage mounted to move past the Wheel, said carriage having curved ways, a Work carrier mounted in said Ways, and means for antomaticallv feeding the work carrier in the directioii controlled by said ways.

38. In a machine of the character described, a grinding Wheel, a carriage mounted to move past thewheel, said carriage having curved ways, a carrier having work clamps and mounted in said Ways, and means for automatically feeding the carrier in the direction controlled by said Ways.

39. In a machine of the character described, a grinding Wheel, a carriage mounted to move past the Wheel, said carriage having curved Ways, a carrier mounted in said Ways, said carrier having clamping devices to hold a plurality of blades in edgewise alinement, and means for automatically feeding the Work carrier in the direction controlled by said Ways.

40. In a machine of the character de scribed, a grinding Wheel, a carriage mounted to move past the Wheel, said carriage having curved Ways, a plate mounted in said ways, a spacer carried by said plate, blocks slidably mounted on opposite sides of said spacer, said spacer and blocks having tongues for engaging oppositeedges of blades to be ground, and means for actuating the blocks toward the spacer to clamp a plurality of blades.

41. In a machine of the character described, a grinding Wheel, a carriage mounted to move past the Wheel, said carriage having curved Ways, a plate mounted in said ways. a spacer carried by said plate, blocks slidably mounted on opposite sides of said spacer, said spacer and blocks having tongues for engaging opposite edges of blades to be ground, and means for actuating the blocks toward the spacer to clamp a plurality of blades, means being provided Bil for automatically feeding the clamp carrying plate in a direction toward the grinding wheel.

42. In a machine of the character described, a grinding wheel, a carriage having Work clamps mounted to slide past the wheel, a rock rod mounted on the carriage, and an arm projecting from said rod to adjust the position of the work in said clamps.

43. In a machine of the character described, a grinding wheel, a carriage mounted to slide past the wheel, said carriage having a pair of clamps for holding a plurality of blades in edgewise alinement, and a rock rod mounted in the carriage and having means for engaging the rear edges of the blades to adjust them in the clamps.

44. In a machine of the character described, a grinding wheel, a carriage mounted to slide past the wheel, said carriage having a pair of clamps for holding a plurality of blades in edgewise alinement, a rock rod mounted in the carriage and having means for engaging the rear edges of the blades to adjust them in the clamps, and a movable finger to engage the front edge of one of the blades to limit the forward position of adjustment thereof.

In a machine of the character described, a grinding wheel, a carriage mounted to move past the wheel, said carriage having curved ways, a work carrier mounted in said ways, and means for automatically feeding the work carrier in the direction controlled by said ways, said feeding means comprising a threaded member carried by the work carrier, a screw engaging said threaded member, and means for actuating the screw when the carriage is shifted.

46. In a machine of the character described, a grinding wheel, a plate mounted to slide past the wheel and having its ends provided with curved ways, a clamp carry- 1ng plate mounted in said ways and having a threaded member, a screw carried by the slide plate and engaging the threaded member, and means for imparting intermittent rotations to the screw to feed the clamp carrying plate toward the grinding wheel.

4 In a machine of the character described, a grinding wheel, a plate mounted to slide past the wheel and having its ends provided with curved ways, a clamp carrying plate mounted in said ways and having a threaded member, a screw carried by the slide plate and engaging the threaded mem ber, a ratchet carried by the screw, a lever having a pawl engaging the ratchet, and an abutment in the path of movement of said lever to efl ect a slight rotation of the screw to feed the clamp carrying plate each time the lever contacts with said abutment.

48. In a machine of the character described, a grinding wheel, a carriage having work clamps mounted to slide past the Wheel, and means for automatically feeding the work clamps transversely of the carriage toward the wheel as the carriage reciprocates.

In testimony whereof I have signed my name to this specification.

ALFRED B. FOWLER.

Certificate of Correction.

It is hereby certified that in Letters Patent No. 1,500,122, granted July 8, 1924, upon the application of Alfred B. Fowler, of Beverly, Massachusetts, for an improvement in Grinding Machines, an error appears in the printed specification requiring correction as follows: Page 6, line 51, claim 13, for the Word oscillating read reciprocating; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 28th day of October, A. D. 1924.

[SEAL] KARL FENNING,

Acting Omnmssioner of Patents.