US2754631A - Knife grinder - Google Patents

Description

July 7, 1956 B. B. STOCKARD, JR

KNIFE GRINDER Filed May 4, 1954 Wavy INVENTOR.

United States Patent KNIFE GRINDER Ben B. Stockard, Jr., Greensboro, N. C., assignor to Newman Machine Company, Inc., Greensboro, N. C., a corporation of North Carolina Application May 4, 1954, Serial No. 427,552

3 Claims. (Cl. 51-92) The present invention relates to a knife grinder and more particularly to a machine for grinding cutterheads which have a plurality of cutting knives projecting from a holder.

It is conventional in the knife grinding art to have a reciprocating work table slide over a bed in which either accurately machined V-ways or dovetailed ways are provided to guide the moving elements. By employing V- ways between the bearing surfaces of the sliding members it is usually necessary that some means be provided to prevent table from tilting or skewing upon knife engagement with the grinding wheel. tailed bearing surfaces or guide members on the bed ways tilt is usually eliminated. However, in each case heavy castings are usually used for the table to provide a stable work rest thus requiring large bearing contact surface areas between the bed and the sliding table that must be accurately machined. Furthermore, due to the large bearing areas the force necessary to slide the table relative to the bed is considerable and usually the use of a mechanism to improve the mechanical advantage therebetween is required, such as, a crank lever with pinion and rack or a gear train system or other conventional devices to traverse the table over the bed will prevent the operator from exercising complete control over the depth of cut, the spark out period and also subjects the knife to considerably more metal removal than is required.

Therefore it is an object of the present invention to provide a knife grinder with a reciprocable table which will slide over a table supporting rail with a minimum bearing surface contact.

Another object of the present invention is to provide a cutterhead knife sharpener in which a work supporting table will overhang a rail member and higher pairing means is provided between the table and rail so that a minimum bearing surface contact results as the table is reciprocated.

Still another object of the present invention is to provide a cutterhead knife conditioner in which a work table engages a supporting rail with higher pairing means so that the length of the reciprocating stroke of the table will be equal to the linear reciprocation of the actuating force acting on the table.

A further object of the present invention is to provide a knife grinder which may be manually reciprocated linearly so that the operator may control the depth of cut and the final spark out or finish cut on the knife.

Another object of the present invention is to provide a knife grinder which has a minimum of machined surfaces by using rollers to contact plane bearing surfaces.

Additional objects of the present invention are to provide a knife sharpener which may be operated with .a minimum of frictional bearing surface contact, one that is simple to operate and economical to manufacture.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following "ice 2 detailed description when considered in conjunction with the accompanying drawings wherein:

Fig. l is an isometric View illustrating a knife grinder embodying the present invention;

Fig 2 is a slightly enlarged partial isometric View of the rail and the table supported bearing roller elements associated therewith;

Fig. 3 is an enlarged partial section view of the overhanging work table supported on the rail member by the higher pairing means; and

Fig. 4 is an enlarged bottom plan view of a section of the table indicating the roller suspension and a bearing surface wiping means.

Referring more particularly to the drawings wherein there is illustrated in Fig. l, a base plate 10 to which the bottom end of a column 11 is retained in a vertical position to support a saddle 12 securely clamped by suitable fastening means 13 to the top end of the column. A grinding attachment 14 is securely supported on the saddle 12 about the motor drive 15, and the motor drive has a shaft 16 that extends horizontally to form an arbor With the use of dovefor receiving the grinding wheel flanges 17, only one being shown, a cup-shaped grinding wheel 18 on the arbor between the flanges 17, and a lock nut 19.

Intermediate the height of the vertical column 11 is a yoke 20 that encircles the column 11 and extends laterally therefrom. The yoke 20 may be releasably clamped in the desired vertical position by the clamping bolts 21. Rotary movement of the yoke 20 is prevented by the elongated square key and rack 22 fastened to one side of the column 11. Extending to each side of the column 11 on the yoke 20 is a pair of horizontal parallel openings 23 and 24 for frictionally retaining a pair of bracket supporting arms 25 and 26 respectively therein. A rail supporting bracket 27 extending transversely across the arms 25 and 26 is held on one end of each arm.

In the illustrated embodiment as shown in Fig. 3, one side of the bracket 27 is provided with sleeves 28 for receiving therein one end of the arms 25 and 26 to which the sleeves are clamped by fastening means 29. It is to be understood however, that individual sleeve flanges or brackets on each arm may be used instead of a transverse bracket. The other side of the bracket 27 has a vertical rail supporting surface 30 in which a plurality of spaced holes 31 are provided. An elongated table supporting rail 32 having ground bearing surfaces 33 and 34 vertically spaced from each other and on opposite sides of the rail, and a horizontal bearing surface 35 on the top of the rail 32 is secured to the bracket surface 30 by suitable fastening means which will engage with the holes 31. The rail bearing surfaces 33, 34 and 35 may be either narrow ground or machined bands extending the length of the rail or the entire surface of each side of the rail may be ground or machined depending upon the contact to be made by the higher pairing means to be employed in cooperation with the surfaces and to be described hereinafter. End stops 35 and 36 which may be made adjustable according to the length of the table stroke will engage with suitable projections 37 and 38, respectively, on the work supporting table 39 to limit the throw of the table during table reciprocation.

For the purpose of this specification the terminology higher pairing shall mean that contact between links will be either of line or point contact as distinguished from lowering pairing which exists when contact be tween elements is plane surface contact.

In Figs. 1 and 3 there is shown an overhanging suspended work supporting table 39 that has a horizontal plane work surface 40 on which a clamping bracket 41 may be secured by fastening means 42 which extends into the table 39. The bracket 41 may be positioned on the work supporting table 39 so that a cutterhead 43 may be positioned adjacent the grinding wheel 18. A downwardly, angularly disposed, depending member 44 extends from the bottom of the table 39 to a position adjacent the bearing surface 34 on the rail 32. The table 39 is suspended from the rail 32 by higher pairing means mounted on the table 39 at suitable positions.

In the illustrated embodiment pairs of freely rotatable rollers 45, 46 and the single roller 47 are mounted on shafts '48, 49, and 56 respectively which shafts are retained in and project from the table 39 and depending member 44. Rollers 45 are mounted to roll on the 'hori zontally spaced vertical rail bearing surface 33. Rollers 46 are mounted to rotate about the horizontally spaced shafts 49 which are retained in a position intermediate the table width and each roller 46 will roll on the top horizontal rail bearing surface 35 to support the vertical load on the table 39. Roller 47 is supported for free rotation about the horizontally spaced vertical shaft '50 at the end of the depending member 44 and the roller 47 will roll on the 'bottom vertical rail bearing surface 34. Rollers 45 and 47 acting on the rail bearing surfaces 33 and 34, respectively, will resist the turning couple moment that acts on the overhanging table 39.

It is Within the contemplation of this invention that the rotatable roller elements may be replaced by other elements to produce higher pairing whether with straight line or point contact, for example, disk wheels, roller bearings, or rotatable ball members may be used. In addition it is within the scope of this invention that the rail 32 may be disposed at other angles than that illustrated and the table 39 may be supported by higher pairing means as required by the disposition of the table.

Reciprocation of the table 39 may be effected manually by :linear reciprocation of the handle 51 attached to the table 39 at an appropriate position within convenient reach of the operator.

A conventional horizontal traversing mechanism 52 is keyed to the bracket 27 to position the work table 39 in the desired horizontal position relative to the grinding wheel 18. The vertical adjusting mechanism 53 is provided with a worm and worm gear (not shown) which worm gear will engage with the vertical key and rack 22 to locate the table 39 in the desired vertical position relative to the grinding Wheel 18.

In order to remove grit or other deleterious matter that may adhere to the bearing surfaces 33, 34 and 35 there may be provided adjacent each of the rollers and contiguous with the fiat bearing surfaces 33, 34 and 35, 'suitable wiping pads 54 that are supported from the table 39 to wipe the critical surfaces. The pads 54 may be felt or other conventional wiping material suitable for removing foreign matter that may cling to the flat surfaces on the rail 32. Additional wiping pads may be supported from the table in direct contact with the rollers 45, 46 and-47.

In operation, the cutterhead 43 normally having a plurality 'of "knives mounted thereon is clamped on the bracket 4-1 with one knife 55 exposed at the desired angle to the grinding wheel 18. By adjusting the horizontal traversing mechanism 52 and the vertical traversing mechanism '53 the exposed knife is oriented to the initial cutting position. They by linearly reciprocating the handle 51 the table will be reciprocated with a linear stroke of the same length as the length of the linear stroke applied to the handle. It will be readily apparent that a minimum of effort is required to shift the table in either direction. Thus when the handle 51 is manually reciprocated'the operator may effectively control the depth of each cutting increment as well as the spark out period.

Although the invention has been described with specific reference to a particular embodiment thereof, it is to be understood that it is not to be so limited, since changes in the parts, such as mechanical equivalents, and in their relative arrangement can be made therein which are Within the full intended scope of this invention as defined by the appended claims.

I claim:

1. A cutterhead grinder comprising a base, a vertical column mounted in said base, a saddle mounted on the column, a grinding attachment having a grinding Wheel and means to drive said grinding wheel supported on the saddle, a yoke encircling said column intermediate the base and the saddle, said yoke having a pair of transverse horizontal openings therein extending on each side of the column, means for releasably locking the yoke in a selected position, a rail supporting bracket having a pair of extending arms in said yoke openings, a rail member mounted to the bracket, said rail having a plurality of exposed bearing surfaces, two of said bearing surfaces being vertically disposed, and spaced apart on opposite sides of the rail and a top horizontal bearing surface, means for moving the bracket and rail horizontally, means for moving the. supporting bracket and rail vertically, a Work supporting table having a plurality of rollers mounted for free rotation on the table, each of the rollers engaging with one of the bearing surfaces on the rail to suspend the working table in a horizontal position, means adjacent the rollers to wipe the bearing surfaces and the rollers, said table being in juxtaposition with said grinding wheel, stops on said rail to limit the length of table stroke, and a manuallyoperable handle fixed to the table whereby the length of reciprocating stroke of the table will be equal to the linear reciprocating stroke of the handle.

2. A cutterhead grinder comprising a base, a vertical column mounted in said base, a saddle mounted on the column, a grinding attachment having a grinding wheel and means to drive said grinding wheel supported on the saddle, a yoke encircling said column intermediate the base and the saddle, said yoke having a pair of transverse horizontal openings therein extending on each side of the column, 'means for releasably locking the yoke in a selected position, a rail supporting bracket having a pair of extending arms in said yoke openings, a rail member mounted to the bracket, said rail having a plurality of exposed bearing surfaces, two of said bearing surfaces being vertically disposed, and spaced apart on opposite sides of the rail and a top horizontal bearing surface, meansforimoving the bracket and rail horizontally, means for moving the supporting bracket and rail vertically, a work supporting table having a plurality of rollers mounted for free rotation on the table, each of the rollers engaging with one of the bearing surfaces on the rail to suspend the working table in a horizontal position, said table being in juxtaposition with said grinding wheel, and a manually operable handle fixed to the table whereby the length :of reciprocating stroke of the table will b equal to the linear reciprocating stroke of the handle.

3. cutterhead grinder comprising a base, a vertical column mounted in said base, a saddle mounted on the column, a grinder attachment having a grinding wheel an'd'm'eans to drive said grinding wheel supported on the saddle, a yoke encircling said column intermediate the base and the saddle, said yoke having a pair of openings therein extending on each side of the column, means for releasably locking the yoke in a selected position, a rail supporting bracket having a pair of extending arms in said yoke openings, a rail member mounted on the bracket, :sai'd rail having a plurality of plane bearing surfaces, two of 'said surfaces being on opposite sides of the rail to resist a turning couple moment, and a third surface being on-the edge of the rail to support a vertical load thereon, means for moving said bracket and rail horizontally, means for moving said bracket and rail vertically, a work supporting table overhanging said rail, higher pairing means interposed between said rail and table, limit stops selectively spaced on the rail to limit table stroke, said table being in juxtaposition with said grinding wheel, and a manually operable .handle fixed fQth'e table whereby the length of the reciprocating stroke of the table will be equal to the linear reciprocating 671,256 stroke of the handle. 680,345 932,791 References Cited in the file of this patent 1,043,948 5 1,863,036 UNITED STATES PATENTS 2,489,453

184,933 Vogeley Nov. 28, 1876 248,744 Holmes Oct. 25, 1881 439,154 Holz Oct. 28, 1890 965,080

6 Whitney Apr. 2, 1901 Morrison Aug. 13, 1901 Le Blond Aug. 31, 1909 Mandley Nov. 12, 1912 Wicke June 14, 1932 Fouquet Nov. 29, 1949 FOREIGN PATENTS France Feb. 8, 1950

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