WO2008096689A1

WO2008096689A1 - Edged tool sharpening device

Info

Publication number: WO2008096689A1
Application number: PCT/JP2008/051709
Authority: WO
Inventors: Takayoshi Takagi
Original assignee: Yoshida Metal Industry Co., Ltd.
Priority date: 2007-02-09
Filing date: 2008-01-29
Publication date: 2008-08-14
Also published as: TW200911456A; JP2008194765A

Abstract

An edged tool sharpening device includes a driving pulley (38) and a driven pulley (40) the distance between which is variable, a motor for rotating the driving pulley (38), an endless abrasive belt (46) passed around the driving and driven pulleys (38, 40) and having an abrasive surface, a guide member (50) arranged near that portion of the abrasive belt (46) which extends between the driving and driven pulleys (38, 40), the guide member determining the angle of inclination of an edged tool (48) with respect to the direction of travel of the abrasive belt (46), and an elastic member (52) urging the driving and driven pulleys (38, 40) in a direction away from each other. The elastic member (52) allows the abrasive belt (46) to warp when the edge of the edged tool (48) is pressed against the abrasive belt (46).

Description

DESCRIPTION

EDGED TOOL SHARPENING DEVICE

Technical Field

The present invention relates to a device for sharpening edged tools.

Background Art Sharpening devices for sharpening the edges of edged tools such as knives are used in the process of manufacture of edged tools, that is, in the edging step, as well as at homes.

A motor-driven edged tool sharpening device disclosed in Unexamined Japanese Utility Model

Publication No. S49-115795, for example, includes a pair of rotatably supported belt pulleys. An endless sandpaper belt with an abrasive surface, namely, an endless abrasive belt, is passed around the pulleys, and one of the pulleys is urged by a spring in a direction away from the other. A tool post and a tool presser for pressing an edged tool against the abrasive belt are arranged above the abrasive belt.

In a motor-driven edged tool sharpening device disclosed in Unexamined Japanese Utility Model

Publication No. S48-55492, a roller disposed in contact with the inner surface of an abrasive belt is urged by a spring, and pulleys and the abrasive belt are surrounded by a cover. Insertion slits with predetermined angles are formed in the top panel of the cover. In these edged tool sharpening devices, the abrasive belt passed round the pulleys is kept taut by the spring, and the angle of inclination of an edged tool with respect to the direction of travel of the abrasive belt is determined by the tool post or the insertion slit. Also, in the sharpening devices disclosed in the above two publications, not only the abrasive belt is pulled taut so as not to slacken but a paper belt guide or the like is positioned close to the inside of the abrasive belt to prevent the abrasive belt from warping.

When using such edged tool sharpening devices, an operator is required to press the edge of an edged tool with a constant force against the abrasive belt all the time while the blade is moved along its length, in order to sharpen the entire edge uniformly from the tip to the heel. Thus, especially in the case where the edge of an edged tool is inclined from the tip to the heel with respect to the longitudinal direction of the blade, the entire edge cannot be uniformly sharpened unless the operator is skilled in handling the sharpening device.

Disclosure of the Invention

It is an object of the present invention to provide an edged tool sharpening device which is simple in construction and yet enables even an inexperienced person to uniformly sharpen the entire edge of an edged tool with ease.

To achieve the object, the present invention provides an edged tool sharpening device comprising: a driving pulley; a driven pulley located away from the driving pulley with a variable distance; a motor for rotating the driving pulley; an endless abrasive belt passed around the driving and driven pulleys and having an abrasive surface; a guide member arranged near a portion of the abrasive belt extending between the driving and driven pulleys, the guide member determining an angle of inclination of an edged tool with respect to a direction of travel of the abrasive belt; and an elastic member urging the driving and driven pulleys in a direction away from each other; The elastic member allows the abrasive belt to warp when an edge of the edged tool is pressed against the abrasive belt.

In the edged tool sharpening device of the present invention, when the edge of the edged tool is pressed against the abrasive belt, the elastic member allows the abrasive belt to warp. Since the abrasive belt warps, the contact pressure between the edge of the edged tool and the abrasive belt is kept constant even if the position of the edge relative to the abrasive belt against which the edge is pressed is displaced to some extent in the traveling direction of the abrasive belt. Namely, the edge of the edged tool is pressed with a constant force against the abrasive belt while the edged tool is moved along its blade length. Consequently, even a user inexperienced at handling the edged tool sharpening device can uniformly sharpen the entire edge with ease.

Also, since the abrasive belt is allowed to warp, a situation where a large force suddenly acts upon the edge of the edged tool from the abrasive belt does not occur even in the case where the edge has a small curvature, thus ensuring safety of the user of the edged tool sharpening device.

Preferably, the abrasive belt is made of leather. With the preferred edged tool sharpening device using the abrasive belt of leather, finish sharpening of the edge can be easily carried out.

Brief Description of the Drawings

The present invention will become more fully understood from the detailed description given hereinafter and the accompanying drawings which are given by way of illustration only, and thus, are not limitative of the present invention, and wherein:

FIG. 1 is a perspective view of an edged tool sharpening device according to one embodiment of the present invention;

FIG. 2 is an exploded perspective view of the edged tool sharpening device shown in FIG. 1;

FIG. 3 is a sectional view of the edged tool sharpening device of FIG. 1;

FIG. 4 is a schematic diagram illustrating the manner of how the edged tool sharpening device of FIG. 1 is used;

FIG. 5 is a partially sectional view illustrating a state wherein the tip part of an edged tool is being sharpened with the edged tool sharpening device of FIG. 1 ; and

FIG. 6 is a partially sectional view illustrating a state wherein the heel part of the edged tool is being sharpened with the edged tool sharpening device of FIG. 1 .

Best Mode of Carrying out: the Invention

FIGS. 1 and 2 illustrate an edged tool sharpening device according to one embodiment of the present invention.

The edged tool sharpening device has a housing 10, and an electric motor 12 is attached to a rear surface of the housing 10. A gear box 14 is fixed to an upper surface of the housing 10 in the vicinity of the electric motor 12 and has a shaft cover 16 protruding integrally from an upper portion thereof. An output shaft 18 is arranged inside the shaft cover 16, and the torque of the electric motor 12 is transmitted to the output shaft 18 through gears (not shown) in the gear box 14.

Also, a guide rail 20 is arranged on the upper surface of the housing 10 and laid in a back-forth direction of the housing 10. The guide rail 20 extends parallel with the output shaft 18 from the front surface of the housing 10 to the vicinity of the bottom of the gear box 14.

A belt unit 22 is removably placed on the housing 10. The belt unit 22 is positioned with respect to the housing 10 by the guide rail 20 and is fixed to the housing 10 by a screw 24. The screw 24 is passed through a through hole in a fixing lug 26 of the belt unit 22 and screwed into a tapped hole 28 cut in the upper surface of the housing 10.

As shown in FIG. 3, the belt unit 22 has a driving pulley case 30 and a driven pulley case 32, which are coupled together by a connecting rod 34 with a space therebetween .

A guide groove 36 for engagement with the guide rail 20 is formed in the bottom of the driving pulley case 30 and extends in a direction perpendicular to the connecting rod 34. Accordingly, while the belt unit 22 is fixed on the housing 10, the connecting rod 34 extends in a width direction of the housing 10, so that the driving and driven pulley cases 30 and 32 are positioned side by side in the width direction of the housing 10.

The driving and driven pulley cases 30 and 32 have driving and driven pulleys 38 and 40, respectively, rotatably arranged therein and having respective rotary shafts 42 and 44 extending in a horizontal direction perpendicular to the connecting rod 34. The rotary shaft 42 of the driving pulley 38 can be coupled with the output shaft 18, and thus, the driving pulley 38 can be rotated by the electric motor 12.

An endless belt made of, for example, leather, that is, an abrasive belt 46, is passed around the driving and driven pulleys 38 and 40 and has an outer surface so treated as to serve as an abrasive surface suited for sharpening the edge of an edged tool. As the driving pulley 38 is rotated, the abrasive belt 46 travels along an endless track, and the driven pulley 40 is also rotated by the traveling abrasive belt 46.

The abrasive belt 46 has two horizontal sections extending in a horizontal direction parallel with the axis of the connecting rod 34, and two semicircular sections extending along the respective outer peripheral surfaces of the driving and driven pulleys 38 and 40. The upper horizontal section of the abrasive belt 46 travels in a horizontal direction between the driven pulley 40 and the driving pulley 38. Also, a major part of the upper horizontal section of the abrasive belt 46 is exposed, and the edge of an edged tool 48 such as a knife is pressed against the outer surface of the exposed region of the abrasive belt 46.

The width of the abrasive belt 46 is smaller than that of the driving and driven pulleys 38 and 40 and is also smaller than the blade lengths of ordinary knives.

The edged tool sharpening device further includes a guide member 50. The guide member 50 functions as a means for determining an angle of inclination of the edged tool 48 being sharpened with respect to the upper horizontal section of the abrasive belt 46, in order that the sharpened edge of the edged tool 48 may have a constant angle. The guide member 50 is formed integrally with the driven pulley case 32 and has guide surfaces 50a against which a flank of the edged tool 48 is pressed. The guide surfaces 50a are located on both sides of the upper horizontal section of the abrasive belt 46 and inclined at a predetermined angle with respect to the upper horizontal section. Also, the edged tool sharpening device has a means for imparting a suitable tension to the upper horizontal section of the abrasive belt 46.

Specifically, one end portion of the connecting rod 34 is securely fixed in the driving pulley case 30 while the other end portion of same is merely inserted through an insertion hole 51 formed through the driven pulley case 32. Thus, the driven pulley case 32 is slidable in the axial direction of the connecting rod 34.

A compression coil spring 52 as an elastic member is disposed around the connecting rod 34 and abutted, at opposite ends, against the driving and driven pulley cases 30 and 32, respectively. The compression coil spring 52 urges the driven pulley case 32 in a direction away from the driving pulley case 30, and because of the urging force of the compression coil spring 52, a suitable tension is imparted to the horizontal sections of the abrasive belt 46.

The following describes the manner of how the aforementioned edged tool sharpening device is used. First, the electric motor 12 is powered to rotate the driving pulley 38, whereupon the abrasive belt 46 revolves and its upper horizontal section travels in a horizontal direction. Subsequently, as shown in FIG. 3, the edged tool 48 is put on the abrasive belt 46 from above the edged tool sharpening device and is pressed against the upper horizontal section of the belt 46 with the edged tool 48 brought into contact with the guide surfaces 50a of the guide member 50. Then, with the edge of the edged tool 48 kept pressed against the abrasive belt 46, the edged tool 48 is moved back and forth in the longitudinal direction thereof, as shown in FIG. 4, to sharpen one flank of the edged tool along its entire length.

After one flank of the edged tool 48 is sharpened, the edged tool 48 is turned upside down and the other flank of the tool 48 is sharpened in like manner. As a result, both flanks of the edged tool 48 are sharpened along their entire length.

With the edged tool sharpening device described above, when the edge of the edged tool 48 is pressed against the abrasive belt 46, the compression coil spring 52 serving as an elastic member allows the abrasive belt 46 to warp. Since the abrasive belt 46 warps, the contact pressure between the edge of the edged tool 48 and the abrasive belt 46 is kept constant even if the position of the edge relative to the belt 46 against which the edge is pressed is displaced to some extent in the traveling direction of the abrasive belt 46.

More specifically, where the edged tool 48 has an arcuate or curved edge extending from the tip to the heel, as the edged tool 48 is moved back and forth for sharpening in the longitudinal direction thereof, the position of the edge relative to the abrasive belt 46 against which the edge is pressed varies depending on what part of the edged tool 48 along its length is being sharpened, as shown in FIGS. 5 and 6. Even if the position of the edge relative to the abrasive belt 46 changes in this manner, the contact pressure between the edge and the belt 46 is kept constant because the abrasive belt 46 warps due to its own flexibility and the elasticity of the compression coil spring 52.

Namely, the edge of the edged tool is pressed with a constant force against the abrasive belt 46 all the while the edged tool is moved along the blade length. Consequently, even a user inexperienced at handling the edged tool sharpening device can uniformly sharpen the entire length of the edge with ease.

Also, since the abrasive belt 46 is allowed to warp, a situation where a large force suddenly acts upon the edge of the edged tool from the belt 46 does not occur even in the case where the edge has a small curvature, thus ensuring safety of the user of the edged tool sharpening device.

The present invention is not limited to the foregoing embodiment alone and may be modified in various ways. For example, the belt unit 22 may be immovably fixed on the housing 10. By detachably coupling the driving pulley 38 with the electric motor 12 ^'as in the edged tool sharpening device of the embodiment, however, it is possible to replace the driving pulley 38, the driven pulley 40 and the abrasive belt 46 collectively as one unit. Namely, the belt unit 22 can be replaced in its entirety with another. This facilitates the use of multiple abrasive belts 46 having abrasive surfaces with different roughnesses to sharpen edged tools.

In the edged tool sharpening device of the above embodiment, the abrasive belt 46 is made of leather, but the material of the abrasive belt 46 is not limited to leather. Where the abrasive belt 46 made of leather is used, however, finish sharpening of the edge can be easily carried out.

Claims

1. An edged tool sharpening device comprising: a driving pulley; a driven pulley located apart from the driving pulley with a variable distance; a motor for rotating the driving pulley; an endless abrasive belt passed around the driving and driven pulleys and having an abrasive surface; a guide member arranged near a portion of the abrasive belt extending between the driving and driven pulleys, the guide member determining an angle of inclination of an edged tool with respect to a direction of travel of the abrasive belt; and an elastic member urging the driving and driven pulleys in a direction away from each other, the elastic member allowing the abrasive belt to warp upon pressing an edge of the edged tool against the abrasive belt.

2. The edged tool sharpening device according to claim 1, wherein the abrasive belt is made of leather.