US2769281A - Grinder - Google Patents

Description

Nov. 6, 1956 c. B. JONES 2,769,281

' GRINDER Filed Oct. 11', 1954 v 3 Sheets-Sheet l INVENTOR. CEC/L 5. JONES A TTOR/VE K C. B. JONES Nov. 6, 1956 GRINDEiR 3 Sheets-Sheet 2 Filed Oct. 11, 1954 INVENTOR. v car/4 a. JO/{ES ATTORNE).

Nov. 6, 1956 c. B. JONES 2,769,281

GRINDER Filed on. 11, 1954 s SheetsESheet s IN VEN TOR. 656/4 5. JO/VES 5 Gav 01 United States Patent GRINDER Cecil B. Jones, Pasadena, Calif.

Application October 11, 1954, Serial No. 461,487

2 Claims. (Cl. 5191) This invention relates to grinders, and has for an object the provision of an all-in-one sharpener adaptable for sharpening pinking shears as well as conventional straightedge cutlery such as common scissors and knives.

A related object is to provide guide means for holding the cutlery at the correct bevel angle relative to the grinding means, and also to prevent too great a bite from being taken by the grinding means.

This invention is carried out in connection with a conventional grinder provided with a base having bearings in which a power driven shaft is journaled. Grinding means such as a Carborundum grinding wheel are turned by this shaft.

A feature of the invention resides'in a track and carriage means for guiding pinking shears past the surface of the grinding means so as to be ground to a correct bevel. This track and carriage means comprises a track which is mounted to the base of the grinder so that its bevel angle to the grinding wheel as well as its spacing therefrom can be adjusted. The carriage is slidably mounted on the track, and has clamping means for holding the pinking shears.

A related feature resides in mounting means for holding the carriage to the track whereby the carriage can be made to yaw as it is moved along the track to vary the angle between the longitudinal axis of the scissor blade and the grinding surface.

An optional feature resides in a forked guide adjustable radially with respect to the grinding wheel for protecting the scissor edge against too deep a bite by the grinding wheel.

The above and other features of this invention will be fully understood from the following detailed description and the accompanying drawings, of which:

Fig. 1 is a perspective view of a grinder according to this invention, particularly illustrating the technique of sharpening a pair of pinking shears;

Fig. 2 is a perspective view of the grinder of Fig. ,1 from a different angle, and with the pinking shears removed;

Fig. 3 is a perspective view of an attachment to the grinding machine of Fig. 1 for grinding straight scissors;

Fig. 4 is a side view of Fig. 2 particularly illustrating the details of the track and carriage; and

Fig. 5 is a fragmentary top view of the carriage of Fig. 2.

Referring to Fig. 1, there is shown an all-in-one sharpener or grinder 10 having a base 11 with a pair of bearing mounts 12, 13 in which a power driven shaft 14 is journaled. This power driven shaft 14 mounts a Carborundurn grinding wheel 15 between the bearing mounts.

Another grinding surface 16 is provided at, an end of the shaft projecting outside the bearing mounts. It may conveniently comprise a central core17 of alternating hard fiber and soft rubber discs which can be compressed so as to expand the soft discs against a sleeve 13 of emery paper or the like.

Between the bearing mounts there is a drive pulley 19 which is connected by a belt 20 to the drive shaft 21 of a motor 22. This motor may be of any desired type such as a gasoline or electric motor.

Guiding means 23 for assisting the operator in sharpening a pair of pinking shears are shown in Figs. 1, 2, and

2 4. With particular reference to Figs.'2 and 4,- it will be seen that a track 24 comprises a flat plate having a pair of curved concentric edges 25, 26 which extend generally transverse'to the grinding wheel 15. It will be appreciated that other than circular-arc edges may be provided for the track depending on the nature of the shears to be sharpened. The track has a support 27 which is attached to a link 28 by means of a pivot 29. 'This link 28 is pivoted to the base 11 of the grinder by pivot 30. It will be seen that this link 28 is rotatable relative to the base and wheel 15, and moves the track 24 toward and away from the grinding wheel 15.

In order to provide means for holding the track in place at a given position, another link 31 is provided which has a longitudinal slot 32 therein. A stud 33 passes through this slot 32 and has a wing nut 33a which can be tightened against the link 31 to hold it in place. The other end of the link 31 is pivotally mounted to link 28 at a position intermediate of pivots 29 and 30 by means of bolt 34 and wing nut 35.

Support 27 is attached to the link 28 by its pivots so that the bevel angle of track 24 can be adjusted relative to the grinding wheel. To hold this adjustment once it is made, a bolt 36 is run through links 28, and a wing nut 37 can be tightened onto its threaded and so as to clamp the links 28 firmly against the support 27. This linkage provides mounting means by which the track 24 can be held at any bevel angle with respect to the grinding Wheel 15, as well as moved toward and away from that wheel.

A carriage 38 is provided for holding a pair of pinking shears 39. This carriage is provided with a shelf 40 at the edge nearest the grinding wheel 15 which leaves a shoulder 41 on top of the carriage. A stud 42 is driven into the shelf 40 for correctly positioning the pinking shears.

A clamp 43 is fixed to the carriage and overhangs the shoulder. It comprises a plate 44 with a depending lip 45. A stud 46 passes through a hole in the plate, and is threaded into the carriage with a spring 4611 between the plate and carriage. When a thumb screw 46b is tightened, the plate is moved down to clamp against a shear blade.

Two studs 47, 48 are threaded into the bottom of the carriage, and each has a plate 49, 50 which extends transversely from the stud. These studs and plates comprise arms which form a channels into which the track 24 will fit so that the carriage can be moved along the track.

It will be observed that these depending studs or arms 47, 48 are spaced from each other by a width greater than the width of the track 24 so that the carriage 38 can bev made to yaw somewhat. This yawing motion is a sidewise rotation of the carriage in the plane of the track. The orientation of this plane is, of course, determined by the adjustment of the track support 27.

A grinding wheel coverSl shields the rear of the grinding wheel 15, and a cover 52 is provided for the drive pulley 19 near the operator. 1

A forked guard 53 is mounted to base 11 by means of a screw 5311. This screw holds the forked guard loosely so that the guard can be made to rock at this point. The forked guard comprises a bent body of metal with tines 56, 57 projecting from the end thereof which is adjacent to the grinding wheel 15'. These tines are spaced from each other so as to stand one on each side of the grinding wheel. A stud 54 passes through the lower end of the forked guard, and ahand screw 55 is threaded onto the I end of the stud. A spring 53 surrounds the stud and bears against the base 11 and the lower end of the forked guard. The hand screw holds the forked guard against spring 58. Tightening hand screw 55 rocks the forked guard and moves the tines radially outward relative to thegrinding wheel. Loosening the hand screw moves the tines ra- 3, dially inward. It will be observed that the hand screw acts as a positive stop against forcing the tines themselves radially inward without loosening said hand screw. The mounting of the forked guard is flexible in that the guard can be adjusted to move the tines without changing the shape of the guard.

In Fig. 3 there is shown a scissor guide 59 which is use ful in sharpening straight scissors. This scissor guide has a post 60 with a hexagonal cross-section which can fit into a hole 61 in the machine base adjacent the grinding Wheel 15. A tightening screw 62 is threaded through the side of the base so as to intersect the hole 61 and hold the post 60 at some adjusted position therein. The scissor guide comprises a bent plate 63 with an attachment flange 64 through which a stud 65 passes from the post 60. A bifurcated flange 67 on plate 63 has two tines 68, 69 which are spaced from each other so as to accommodate the grinding wheel 15 between them. A wing nut 66 is provided for tightening the post and the attachment flange together so that the angle of the tines can be adjusted relative to the grinding wheel. I

The operation of this sharpener to sharpen a pair of pinking shears will now be described. The pinking shears are opened and the serrated edge 70 of one blade is pointed toward the grinding wheel 15. The back of the blade rests against the shoulder 41 and the stud 42. Thus the longitudinal axis of the blade is generally transverse to the grinding wheel. Then the clamp 43 is tightened down so that the overhanging plate firmly holds the blade of the shears.

It will be appreciated that the carriage can be moved along the track so as to move the blade across the grinding surface of Wheel 15, and grind a surface similar in contour to that of the track, although of a different radius. Varying the contour of the track'edges 25, 26 will accordingly vary the contour of the scissor adge as ground. Since most pinking shears have a curved edge, the track itself Will be curved as shown in the drawings.

To sharpen the shears, the guiding means 23 isset at the proper distance from the grinding wheel, by moving link 28 as appropriate, and tightening wing nut 33a. Then the proper bevel is selected by tilting the track on pivot 29 and tightening wing nut 37. This tiltable track enables pinking shears with a wide range of cutting edge angles, such as 75or greater to be ground. The power is turned on to rotate the shaft, and the carriage is moved along the track so that the shear edge is ground by the grinding wheel.

As an aid in preventing the grinding wheel from taking too great a bite in the shear edge, the forked guard is adjusted by turning the hand screw 55 to move the tines 56, 57 to a radial position defining the deepest cut which can be taken by the wheel. When the deepest cut is taken, the shear edge strikes the tines and not the grinding wheel.

Many of the newer types or" pinking shears have a curve near the end which is sharper than the general curve of the blade. The extra spacing between the studs 47, 48 is provided to allow for this sharper curve. As the pinking shears are ground Where the shear edge curve is similar to that of the track, the studs are maintained straight across from each other, so as to be aligned with the radius of the curved track edges 25, 26. When the sharper-curved end is reached, the carriage can be made to yaw, so that the bevel of the shear remains the same, due to the track adjustment, but the carriage and shears are rotated in that plane. In this manner, the entire shear edge is ground at the correct bevel, and over the major portion of the length, at the curve defined by the track. A certain element of skill is called for at the tip but damage due to mistakes is largely eliminated by the forked guard 53. Thus, free-hand work, which is still guided and steadied, can be accomplished with this guiding means.

The use of the straight scissor guide 59 shown in Fig.

3 will now be described. The guiding means 23 are dropped to bench level by loosening wing nut 33a, and are thus out of the way. The post is inserted into hole 61, and screw 62 is tightened down. Then the wing nut 66 is loosened and the bifurcated flange 67 adjusted at the desired bevel angle relative to the guiding wheel for grinding the scissor edge. The forked guard 53 is adjusted to protect the scissors against an excessive bite by the grinding wheel. The scissors are now simply moved across the grinding wheel in contact therewith with the tines, and the desired surface will be ground. The tines of the forked guard act as guides to keep the edge straight, and the bevel is maintained by the angular adjustment of the bifurcated flange.

For knife sharpening purposes the grinding surface 16 will be found useful. According to common practice the knife is simply rested flat on the wheel and moved back and forth across the grinding surface while the shaft rotates so as to grind the desired sharp edge.

This grinder provides, in a single unit, means for sharpening most of the common types of cutlery including pinking shears. Straight edges are simply and accurately ground with the proper bevel by use of the scissor guide and the forked guard. Flat surfaces such as knives are expeditiously sharpened by use of the elongated cylindrical grinding surface 16.

In addition curved surfaces may be ground by use of the carriage and track, and means are provided for varying the position of the blade as necessary for sharpening curves of varying radius.

The forked guard permits guided freehand grinding substantially with a diminished risk of accidentally removing excess metal from the scissors.

This invention is not to be limited by the embodiments shown in the drawings and described in the description, but only in accordance with the scope of the appended claims.

I claim:

1. In a grinder having a rotary grinding wheel journaled in a stationary base, means for grinding pinking shears across the surface of said grinding wheel comprising a track with a pair of curved concentric edges, a link pivotally mounted to the base, and the track being pivotally mounted to the link, whereby the tracks bevel angle and distance from the grinding wheel can be independently adjusted, a carriage mounted on said track, arms on said carriage for engaging with the curved concentric edges of the track, said arms being spaced by a distance greater than the spacing of the curved edges from each other, whereby the carriage can be made both to slide along the track and to yaw on said track, means for holding a blade to be sharpened to the carriage, whereby a blade held to the carriage is moved across the grinding wheel at a bevel and distance relative thereto which is determined by the setting of the track and by movement of the carriage along the track, and in which a forked guard is provided comprising a body and two spaced tines projecting from said body, said body being flexibly mounted to the base, and the tines straddling the grinding References Cited in the file of this patent UNITED STATES PATENTS Libbey Dec. 24, 1872 Schwantes et a1. Dec. 22, 1908 Kelley Sept. 3, 1929

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