US2945332A - Knife sharpener for cutting machine - Google Patents

Description

July 19, 1960 J. 1B. GuRY, JR 2,945,332 KNIFE SHARPENER FOR- CUTTING MACHINE Filed Sept. 17. 1958' r; I FIG. 3

' INVENTOR.

JOHN B. GURY, JR. FIG. 2 BY ATTORNEYS KNIFE SHARPENER FOR CUTTING MACHINE John B. Gury, Jr., 1229 Arch Terrace,

Richmond Heights 17, Mo.

Filed Sept. 17, 1958, Ser. No. 761,626

6Claims. ((151-246) The present invention relates generally to machines for cutting multiple layers of cloth, and more particularly to improvements in knife sharpeners for cloth cutters of reciprocating knife type.

The invention has to do with cloth cutters and knife sharpeners of the kind illustrated and described in applicants Patent No. 2,737,763 of March 13, :1956, and provides certain improvements in the sharpening device disclosed in that patent. Such sharpeners employ a pair of abrasive belts having their active flights extending in crossed relationship so as to produce the desired bevel and edge on the opposite side portions of the blade.

It is an important object of this invention to provide means in the knife sharpening assembly which causes adjacent inner edges of the belts to apply the more effective grinding action to the knife, and therefore afford an accurate true knife edge having the optimum keenness. An important object is achieved by the provision of means for twisting the crossed belts in a manner so that the closest edges of the belts are urged against opposite sides of the knife with a pressuregreater than the other edges of the belts for best grinding action.

Other advantages are realized by the preceding structural arrangement in that it closely approaches the optimum condition wherein the belts are directly opposite each other, but cannot be attained because the belts actually cross each other.

Another important objective is realized in that 'the idler nited States Patent pulleys of the knife sharpening assembly are provided with means that engage a vertical element disposed between such pulleys so as to cant the pulleys in the same direction from the'vertical in order to apply effective pressurebetween the knife and particular edges of the belts, whereby to provide the advantageous function which was discussed previously.

Still another important object is achieved by making the flanges of the idler pulleys of a specific dimensional relationship and by arranging the pulleys so that the flanges engage a vertical element disposed therebetween, whereby to provide the twisting elfect of the belts previously discussed.

The foregoing and numerous other objects and advantages of the invention will more clearly appear from the following detailed description of a preferred embodiment, particularly when considered in connection with the accompanying drawing, in which:

Fig. l is a side view of a cutting machine equipped with a sharpening device in accordance with this invention;

Fig. 2 is an enlargedtop elevational view, partly in cross section, of the knife sharpening mechanism as. seen along line 22 of Fig. 1;

Fig. 3 is an end view of the knife and knife sharpening assembly as seen from line 3-3 of Fig. 2, and

Fig. 4 is a diagrammatic view of the knife and abrasive belts.

Referring now by characters of reference to the drawings, and first to Fig. 1, the cutting machine to which this invention applies may be of any suitable type having a base 10 supporting a standard or pedestal 11in which a knife 12 is mounted to reciprocate vertically. A motor 13 is operatively connected toknife 12 by a mechanism such as that illustrated and described in applicants Patent No. 2,737,763 issued March 13, 1956. This connecting mechanism is enclosed within housing 15.

A handle 16 is usually attached to the standard 11 whereby the machine may be manipulated during the cutting operation.

' According to this invention, a frame and housing 17 is secured to housing 15 and hence connected to the motor 13. A grinder carriage 20 depends from and is supported by mechanism withinhousing 17. The grinder carriage 20 is mounted and guided in its up and down movements in any suitable or desired manner, for example as disclosed in applicants Patent No. 2,737,763 issued March 13, 1956. 1

For example, a pair of screws 21 are driven in opposite directions by a drive connection disclosed in the above mentioned patent, and serve to move the grinder carriage 20 up and down along the knife 12. A driving Wheel 22 which may be provided with a tire 23 of rubber or the like to provide a frictional driving surface operatively innerconnects with the motor 13, and operatively innerconnects with the screws 21 to rotate and hence reciprocate said carriage 20, all in a manner disclosed in the above mentioned prior patent. Again, this mechanism is not shown in any detail since it is not directly involved in this invention.

Extending downwardly from the carrier 20 is a sleeve 24. Mounted to rotate on sleeve 24 is a drive pulley 25.

'Journalled within sleeve 24 is a vertical spindle 26 having secured to the lower end thereof a drive pulley 27 similar to pulley 25. The particular mounting of drive pulleys 25 and 27 and their operatively connection with screws 21 is as disclosed in the aforesaid Patent No. 2,737,763. It is seen that the drive pulleys 25 and 27 are located one immediately above the other and mounted for rotation on a common vertical axis. These drive pulleys 25 and 27 are driven in opposite directions of rotation. Because the carriage 20 is supported on the screws 21, it will move up and down with those screws.

Referring now to Fig. 2, fixed on carriage portion 30 depending from carriage '20 in front of drive pulleys 25 and 27 is a leaf spring 31. This spring 31 is mounted on a level with the drive pulley 25 and extends outwardly therefrom as is shown in Figs. 1 and 2. Mounted on the leaf spring 31 is a bearing bracket 32 having a shaft portion 33 bent into C-form as shown in Fig. 2 and slipped over the leaf spring 31. The bracket 32 is thus movable along the leaf spring 31. A coil spring 34 is connected to a pin 35 on the leaf spring 31 and to the tab 36 formed on the shank portion 33. The coil spring 34 therefore tends to urge the bearing bracket 32 outwardly away from the drive pulley 25. The bracket is provided with a forked end, as is shown in Figs. 2 and 3, and is equipped with bearings 37 in which an idler pulley 49 is journalled. The leaf spring 31 and bracket 32 constitute a resilient arm. An abrasive belt 41 is arranged to run on the pair of pulleys 25 and 40.

A similar structure provides for a similar sharpening belt '46 to run on the drive pulley 27. For example, a leaf spring 42 is fixed to the opposite side of carriage portion 30. A bearing bracket 43, similar in'all respects to the bearing bracket 32, is similarly mounted on the leaf spring '42 with a coil spring 44- urging it outwardly from the drive pulley 27. The leaf spring 42 and bracket 43 constitutes a resilient arm. The bracket 43 carries an idler pulley 45, and sharpening belt 46 rides on the two pulleys 27 and 45.

As may be seen from Figs. 2 and 3, these belts 41 s3 and 46 are so located as to pass one on each side of the knife blade 12. The belts are urged with pressure against the blade while the coil springs 34 and 44 provide tension in the belts. As the :entire sharpening, apparatus is carried by the carriage20, it moves up and .down along the blade in response to the movement of'the screws 21. The knife sharpening apparatus is provided with means for twisting the belts 41 and 46 so that the adjacent inner edges 47 bear against the'knife edgewith a greater. pres.- sure, as indicatedby force vectorsin Fig. 4, than the outer edges 48. This action enables the more effective grinding by belts 41 and 46 tooccur in immediately adjacent zones, and closely aproximates the optimum action whereby the belts would :be locateddirectly opposite each other. This grinding action provides an accurate keen edge on the blade 12 without any burrs.

To accomplish this result, the upper flange 50 of idler pulley 40 is of greater diameter than the lower flange 51, as is best shown in Fig. 3. Similarly, the lower flange 52 of idler, pulley 45 is of greater diameter than the upper flange 53. The flanges 50-53, and hence idler pulleys 40 and 45, ride on the knife guide'll, and because of their particular structural relationship, the idler pulleys 40 and 4-5 are tilted from the vertical in the same direction, whereby to twist the abrasive belts 41 and 46. Because the belts 41 and 46 are flexible the entire width of the belts is urged against the'knife edge. However, because of the twisting action alforded by the canted relationship of idler pulleys 40 and 45, a greater pressure is exerted by the inner edges 47 of the belts against the knife edge than the pressure exerted by the outer edges 48, as previously discussed.

A pressure foot 54 is mounted on the lower end of a shank 55 vertically slidable within housing 17 and along the carriage 20 and carriage portion 30. As well understood in the art, .the pressure foot 54 is adjustable to different elevations suited to dilferent layers of material to be cut.

Although the invention has been described by making detailed reference to a single preferred embodiment, such detail is to be understood in an instructive, rather than in any restrictive sense, many variants being possible within the scope of the claims hereunto appended.

I claim as my invention:

l. A knife sharpening-mechanismfor cutting machines having a knife guided for reciprocal movement, a grinder carriage movable up and down along said knife, a pair of driving pulleys mounted on said carriage for rotation on a common vertical axis, the driving pulleys being located one immediately above the other, a spring arm supported on said carriage opposite each said driving pulley to' extend outwardly therefrom, an idler pulley mountedon each spring arm, a sharpening belt on each pair of said driving and idler pulleys, said belts having adjacent inner edges and opposite outer edges, said idler pulleys being disposed on opposite sides of the knife and being disposed one above the other, said spring arms being set to bias said belts for pressure against the knife, each said idler pulley having opposed annular flanges, the top idler pulley having its upper flange and vertical means between said idler pulleys engaging said flanges so as to tilt said idler pulleys from the vertical so that adjacent inner edges of said belts are urged against said knife with a pressure greater than the outeredges of said belts.

2. A knife sharpening mechanism for cutting machines having a knife guided for reciprocal movement, a grinder carriage movable up and down along said knife, a pair of driving pulleys mounted on said carriage forrotation on a common vertical axis, an idler pulley supported on said carriage opposite each, of said driving pulleys, a sharpening belt on each pair of said driving and idler pulleys, said belts have adjacent inner edges and opposite outer edges, said idler pulleys being disposed on opposite sides of the knife, and means slidably engaging said idler pulleys to tilt said idler pulleys from the vertical in same direction sothat the adjacent inner edges'of said belts areu'rgeaagainst saidknifewith a pressure greater than the outer edges of the said belts.

3. A knife sharpening mechanism for cutting machines having a knife ,guided for-reciprocal movement, a grinder carriage movable up and down along said knife, a pair of driving pulleys mountedionirsaid carriage for rotation on a common vertical axis, an idler pulley supported on said carriage opposite of each said driving pulleys, a sharpening belt on each pair of said driving and idler pulleys, said 'beltsihaving'adjacentinneriedges and opposite outer edges,

saidliidleripulleysIbeing disposed on opposite sides of the knife, each of said idler pulleys having opposed annular flanges, one flange of each idler pulley being of greater diameter than .the otl'lerfflange, and :means engaging said flanges of each idler pulley so as to tilt said pulleys from the vertical so that adjacent inner edges of said belts are urged against said knife with the pressure greater'than the outer edgesof said belts.

4. The combination and arrangement of elements as recited above in claim 3, but further characterized in that the said means engaging the idler pulley flanges includes a vertical element disposed between said idler pulleys.

. 5. A knife sharpening mechanism for cutting machine having a knife guided for reciprocal movement, a grinder carriage movable'up and down along said knife, a pair of driving pulleys mounted on said carriage for rotation on a common vertical axis, an arm supported on said carriage opposite each said driving pulley to extend outwardly therefrom, anidler pulley-mounted on each arm, a sharpenin'g belt on each-pair of said driving and idler pulleys, said idler pulleys being disposed on opposite sides of the knife, saidarms'beingset to bias said belts for pressure "against the -'knife,the belts including adjacent inner edges and outer. opposite edges, a vertical element disposed between said idler pulleys, and means on each idler pulley engaging the vertical element to tilt the idler pulleys from the vertical.

6. A knife sharpening mechanism for cutting machine having aJknife'gu'ided for reciprocal movement, a grinder carriagemovable up'and down along said knife, a pair of driving pulleys mounted on said carriage forrotation on a common vertical'axis, and arms supported on said car.- riageoppositeeach'said driving pulley to extend outwardly therefrom, an idler pulley mountedon each arm, a sharpening belt on each pair of said driving and idler pulleys, said idler pulleys being disposed on opposite sides of the *knife, said arms being set to bias said belts for pressure against the knife, the'belts including adjacent inner edges "and outer oppositeedges, a vertical element disposed between said idler pulleys, each said idler pulley being provided with opposed annular flanges, one flange of each idler pulley beingof greater diameter than the other flange, the flanges'of said idler'pulleys engaging the vertical element to tilt the idlerpulleys from the vertical.

References Cited' in'the file of this patent UNITED STATES PATENTS 650,004 Brinkman May 22, 1900 2,737,763 I Mar. 13, 1956

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