A TOOL AND ARRANGEMENT FOR THE TREATMENT OF A CUTTING EDGE

TECHNICAL FIELD

The invention concerns a device arranged for the treatment of a cutting edge. The invention also concerns a tool, which is mountable and combined in the device and which is operative for the treatment of a cutting edge, such as a knife-edge, by means of grinding, dressing, or pohshing.

BACKGROUND AND PRIOR ART

Devices and tools of this type are previously known, comprising tools, which are located opposite each other in pairs and which are mounted and mutually movable in reciprocating directions of motion, wherein the tools comprise a plurality of segments, which are arranged at spaces and have a respective contact surface, which segments are arranged to alternately engage the segments of the opposite tool, so that, between the contact surfaces of the opposed segments, there is formed a V-shaped notch of variable depth adapted for the insertion of a cutting edge to be treated, in addition to which at least one of the tools features segments having an active, grinding or dressing or polishing contact surface.

In the treatment of a knife, the knife-blade is inserted down into the V-shaped notch so that the cutting edge of the knife is pressed against the contact surfaces of the tools, whereupon the knife is brought to and fro, primarily in the longitudinal direction of the knife-blade but alternatively in an oscillating motion containing both horizontal and vertical direction components, the knife-edge being ground, dressed, or polished by wear against the active contact surfaces of the tools.

The tools are mounted in a respective holder, and are resiliency biased toward each other. Under load from the knife-blade inserted between the tools, the tools are pressed apart against the action of the biasing springs. Therefore, the depth of the V-shaped notch varies in relation to the load of the knife-blade on the tools.

In known tools, the segments are integrated to a uniform block. This block may be manufactured from a ceramic material, which itself is efficient for the grinding, dressing, or poUshing of the knife-edge. The block may alternatively be

manufactured from metal or plastic having a surface layer applied to the active contact surfaces of the segments, such as grains of diamond or another mineral having a removing or polishing effect on the knife-edge.

Characteristic of devices of this type is that the result in the treatment of the knife- edge is partly depending on how the knife-blade is oriented between the tools. More precisely, for a satisfactory result, it is necessary that the knife-blade is horizontally oriented between the tools in the treatment of the straight part of the knife-edge. This is explained by the fact that the tools are integrally formed blocks, the mutual position of which is determined by the lowest point of the knife-blade, and therefore only the outermost segment of the respective block acts against the knife-edge if the knife-blade is angled during the treatment. This condition may in the long run also cause an uneven wear-out of the tools which, if applicable, therefore do not achieve the maximum service life.

THE INVENTION IN BRIEF The invention aims at obviating the above mentioned disadvantage and providing a device and a tool, which is less dependent on the knife-blade being brought in a horizontal path in the treatment of the cutting edge.

Another object is to provide a device and a tool, which protects the sensitive knife- edge against deformation caused by an exaggerated load upon depression of the knife-blade against the tools during the treatment of the cutting edge.

A further object is to provide a device and a tool, which in a simple way is readjustable for the treatment of knives having different angle of the knife-edge.

The first mentioned object is met in a device of the kind mentioned by way of introduction, wherein the segments of an individual tool are individually and independently of the other segments of the same tool movably mounted in a holder arranged for the purpose, as well as biased in relation to the holder in the direction of an opposite tool.

An advantage of said solution is that the active contact surfaces of all segments are brought into abutting contact with the cutting edge of the knife-blade, also if the knife-blade is angled and moved in a non-horizontal or arched path between the tools.

In this connection, it should be clarified that the tools may be arranged for the treatment of one-sided ground and sharpened knives. In such an embodiment, one of the tools is operative for the treatment of the cutting edge while the other tool only serves as anvil. In that connection, the abutting tool usually features a vertical support surface, perpendicular to the base or bottom of the device, while the active tool typically features an oblique, straight, or arched contact surface toward the one-sided shaped cutting edge. Said V-shaped notch comprises in this particular embodiment a vertical leg and an angled leg. In the other embodiments, the V- shaped notch comprises two angled legs, and usually with a bisector extending perpendicular to the base of the device.

In order to prevent the cutting edge from contacting the bottom of the V-shaped notch, it is an advantage if the tools are assigned an inner and an outer end stop, which determine the possible movement length of the tools, the same being determined in such a way that the tools in their outer end positions form a gap- shaped opening in the bottom of the V-shaped notch.

Even if the knife-blade is pressed by such a force that the tools are pressed out to their outer end stops, the cutting edge will accordingly not meet any obstacle that could damage it. It will be appreciated that the air gap which is formed between the tools in their outer end positions should not exceed the thickness of the knife-blade, and it may in most applications amount to the order of 1-2 mm.

In one embodiment, at least one of the tools is adjustably arranged in the device, and more precisely readjustable from a first position, wherein the tools located opposite each other form an intermediate first angle, to a second position, wherein the tools form an intermediate second angle different from the first angle.

Preferably, the tools are adjustably arranged in pairs and continuously variably or in fixed steps readjustable for changing the intermediate angle. It is in that connection preferred that the tools are readjustable for the setting of an

intermediate angle at least within the interval of 30-40, and most preferred that the intermediate angle can be varied within the interval of 15-60°.

The angular setting function may advantageously be formed so that the tools are positively adjustable so that the bisector of the intermediate angle in all angular setting positions extends perpendicular to the base of the device. This may, for example, be achieved by the tools being mutually turnably coupled by a swivel joint located to the bisector, as well as movable in relation to a ramp, wherein, by relative rotation or displacement between ramp and holder, the holders are brought to turn in said swivel joint. The segments forming the individual tool and supporting the active contact surfaces of the tool have suitably the shape of a flat plate having four side edges, wherein an angled, straight, or arched contact surface forms a corner connecting two adjacent side edges.

In the individual tool according to the invention, the segments are individually fitted in a holder arranged for the purpose, and in fitted position individually movable between a projected and a retracted position in the holder, as well as, in relation to the holder, biased in the direction of the projecting position.

The segments may be made as ceramic bodies, which, due to the intrinsic properties of the ceramic material, are effective for the treatment of the cutting edge in the form of grinding, polishing, or dressing/ steeling. The segments may alternatively be made as bodies of plastic or metal, which, in the contact surface, are coated with diamond or another removing material.

In a production-wise particularly meritorious embodiment, the segment features a separately manufactured metal profile, which is fitted on the contact surface and coated with diamond or another removing material for the treatment of the cutting edge.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is explained in more detail below, reference being made to

embodiment examples schematically represented in the drawings. In the drawings Fig. 1 shows a broken away portion of a device for the treatment of a cutting edge shown from a side,

Fig. 2 shows a corresponding side view of the device in Fig. 1 shown in an alternative operation position;

Fig. 3 shows the device in Figs. 1 and 2 in a view from above, Fig. 4a shows a tool included in the device in a first angular setting position, Fig. 4b shows the tool in Fig. 4a in a second angular setting position, and Fig. 5 shows a metal profile mountable in the tool.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT EXAMPLES Figs. 1 and 2 shows in partially broken- away side views a station 1 comprising tools 2 and 3 in a device for the treatment of a cutting edge, such as a knife-edge 4. For the purpose, the tools 2 and 3 support contact surfaces 5 and 6 (see Fig. 2) against which the knife-edge is pressed by a downwardly directed force F and is moved to and fro, in a motion essentially perpendicular to the plane of the drawing. The contact surfaces 5 and 6 are formed on a side edge of the respective segment included in the tool, and, during the wear of the knife-edge against the contact surfaces, effective to provide a machining of and improvement in the knife-edge. A device for the treatment of a knife-edge may contain a plurality of corresponding stations having tools the contact surfaces of which are arranged for different types of treatments, such as grinding, polishing, or dressing/steeling of the knife-edge.

The tools 2 and 3 are fitted in a respective holder 7 and 8 to be mutually movable in opposite directions of motion. A boss 9 or 10 in the back side of the tool is for the purpose movably mounted in the holder in question, springs 11 and 12 acting between holders and tools for the bias of the tools toward each other and from the respective holder.

The tools are controlled in their movements, on one hand by the fact that the lower edges of the tools are running in grooves 13 formed in the base 14 of the device, and on the other hand by the fact that the upper edges of the tools are running in grooves 15 formed on the inside of a lid or cover 16. The cover 16 typically extends down to the base 14 on both sides of the device, but features an opening 17 for the insertion of the knife-blade.

The length of the movements of the tools 2 and 3 in reciprocating directions is limited by an inner end stop 18 and an outer end stop 19. The inner end stop 18 is placed to guarantee that a V-shaped notch 20 initially is provided between the tools to allow insertion of the knife-blade when the tools are situated in their most brought- together position, as is shown in Fig. 1. The outer end stop 1 is placed to guarantee a narrow air gap 21 between the tools when these are situated in their most separated position, as is shown in Fig. 2. The width of the air gap may amount to from approx. 0,5 mm to approx. 2 mm, and should not allow that the knife-edge reaches up to the base 14 of the device in the most separated position of the tools.

With reference to Fig. 3, it should be explained that each one of the tools consists of a number of, and more precisely at least two or more, separate segments 2', 2", etc. and 3', 3", etc., respectively, which are individually movably mounted in the appurtenant holder 7 and 8. Consequently, each one of the segments features a boss individually mounted in the holder, and each segment is assigned a separate spring, which biases the individual segment individually in the direction from the holder, i.e., toward the opposite tool in the fitted position of the tools. A guiding groove 13 is formed in the base 14 of the device for the lower edge of each one of the segments. Correspondingly, separate guiding grooves for the upper edge of each one of the segments are arranged on the inside of the cover of the device. Each one of the segments is consequently also assigned separate inner and outer end stops 18 and 19 arranged in the respective guiding groove 13.

The guiding grooves 13 and 14 are separated by partition walls, which allow the segments of one tool to move in a space formed between adjacent segments of the opposite tool. The segments 2', 3', etc. may be compared to four-sided plates from which a corner has been cut off so that a fifth side edge is formed to constitute the contact surface 5 or 6 that machines the knife-edge. Even if the embodiment examples without exception show straight contact surfaces, it will be appreciated that the contact surfaces just as well alternatively may be concavely or convexly arched for the treatment of knife-edges having the corresponding shape. In all cases, the contact surfaces are oriented so that, between opposite contact surfaces, an intermediate angle a is formed, which determines the angle of the treated knife- edge.

In Figs. 4a and 4b, a device is shown in which the tools 2 and 3 with appurtenant segments 2', 3', etc. are movably mounted and readjustable for the alteration of the intermediate angle a of the active contact surfaces. More precisely, an angular setting function is shown wherein the tools are positively adjustable so that the bisector B of the intermediate angle extends perpendicular to the base of the device in all angular setting positions. The tools 2 and 3 with appurtenant holders 7 and 8, respectively, may for the purpose be carried by each a respective separate part 22 and 23 of the base of the device, in addition to which the parts 22 and 23 of the base are mutually turnably coupled by a joint 24 located to the bisector B. The base parts 22 and 23 rest on a plate 25, which is movably arranged in relation to the base parts 22 and 23. Upon displacement of the plate 25 in relation to the base parts and the tools, in the direction of the arrow according to Fig. 4b, the base parts 22 and 23 are lifted by a respective ramp 26 and 27 under mutual rotation of the base parts in said joint 24.

Instead of the linearly displaceably arranged plate 25 described above, the same may be arranged rotatable and be provided with a rising/ falling cam curve in its upper side for lifting of the base parts and setting of the intermediate angle of the tools by rotating the plate. A rotation-controlled setting function may alternatively be realised in the form of two rotatably arranged plates 25 having cam curves formed in the upper sides of the plates , the two plates being in engagement with each other by external teeth for simultaneous and similar rotation on the respective shafts thereof.

In all cases, the angular setting may be arranged to be effected in fixed steps or continuously variably, wherein, at least in the latter case, the setting function may comprise a locking, which fixes the tools in the set position.

By dimensioning on one hand the assigned angle of the contact surfaces in the segments and on the other hand the assigned area of the angle of rotation of the tools in the joint 24, the intermediate angle a between tools/contact surfaces may be varied within an angle interval, which may amount to the order of 15-60°, or if required even more.

An advantage achieved by the invention is a simplified production of tools and segments. This advantage is possibly the greatest what concerns tools consisting of ceramic material, because pressing and sintering of flat segments is a considerably less complicated process than, e.g., the production of an integrally formed and segmented block. By the fact that the tool according to the invention consists of individually movably mounted and biased segments, the need of finishing and complex mould manufacturing largely disappears, and therefore, production of tools of metal or plastic is also considerably simplified compared with production of continuous blocks.

This simplification what concerns the production of the tool is brought a step further forward by the embodiment in which the active contact surface of the tool is separately manufactured and mountable onto the segment. An embodiment of a separate and replaceable contact surface is shown in Fig. 5 in the form of a rail 28, which comprises folded-over edges 29, 30, which are insertable in grooves of the corresponding shape, recessed in opposite side surfaces of a segment 2'. The rail 28 may be made of metal and arranged to be fixed on the segment by, e.g., clamping, shrinkage, or agglutination. The rail 28 is typically coated with diamond or another material-removing or in another way machining material for the treatment of a knife-edge.

Because the invention has been described with reference to embodiment examples schematically shown in the drawings, it will be appreciated that the detailed embodiment may be varied within the scope of the solution, such as this appears from the attached claims.