DE2535583A1 - PROCEDURE FOR SHARPENING CIRCULAR SAWS AND SAEGEN SHARPENING MACHINE FOR CARRYING OUT THE PROCEDURE - Google Patents

Description

7950 Biberach / Riss
Wilhelmstrasse 20/22

Process for sharpening circular saws and saw sharpening machine for carrying out the process.

The invention relates to a method for sharpening circular saws whose teeth are thicker than their saw blade, the rotatably mounted in its center and clamped in each case in an area near the foot of a tooth before a grinding wheel is moved along this tooth. The invention also relates to a saw sharpening machine for performing such a procedure.

Circular saws whose teeth are thicker than the saw blade can be produced in a known manner by melting one hard metal on rough pre-machined teeth, by upsetting such teeth and in particular by having such teeth with Tungsten carbide plates are fitted. In general it is required to have teeth on her chest, on her back and to grind on their flanks to get sharp teeth of the desired shape, with teeth of different shapes, for example pre- and post-cutting teeth, alternate with each other

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can. Sharpening in connection with the invention is both the initial grinding to produce the desired To understand tooth shape as the re-sharpening of teeth that have become blunt during operation.

For the performance of a circular saw as well as for the accuracy and surface quality of the cuts it produces In addition to the correct design of the teeth, it is important that all teeth with the same function use the same circular path during operation describe what is commonly referred to as a flight circle. For example, all pre-cutting teeth should have the same flight circle form and all Nachschnexdezähne a different one but for all Nachschnextezähne

form the same flight circle. Compliance with the specified flight circles is up to a certain extent with every circular saw impaired by axial runout and runout errors. Runout errors can be used in the manufacture of circular saws without any particular difficulties within the range for the respective purpose Keep the specified tolerance range. On the other hand, facing errors in the saw blade are difficult to eliminate; this is especially true for circular saws fitted with hard metal, and in particular those intended for cutting metal; With such circular saws, the blade thickness in relation to the saw diameter is considerably greater than with circular saws for wood and similar materials, and as the sheet thickness increases, it becomes increasingly difficult to eliminate runout errors time consuming.

The invention is based on the object of producing circular saws, in particular circular saws equipped with hard metal for processing metals, so perfect that the given flight circles of all teeth without special Workload can be complied with with sufficient accuracy.

So far, the method described at the beginning has been carried out in such a way that the saw blade is radially in the area

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has clamped within the tooth to be sharpened between a stationary abutment and a clamping jaw and the plane of the abutment is used as a reference plane for setting the grinding wheel, especially when grinding the tooth flanks Has. The teeth sharpened in this way sit exactly symmetrically on the area of the saw blade that bears them; everyone However, the axial runout of the saw blade naturally has the consequence that all teeth affected by it by the amount of the horizontal runout deviate from the specified flight circle. This also applies if the saw blade is clamped in this way when its teeth are sharpened becomes that his plan runout is no longer recognizable during the clamping.

In contrast, the stated object is achieved according to the invention in the method described at the outset in that when clamped, the axial position of the clamped area, which is given with a relaxed saw blade and is afflicted with an axial runout Maintain as precisely as possible with respect to the center of the saw blade and the movement of the grinding wheel without regard is carried out on the axial runout according to the axial position of the center. Reference plane for setting the grinding wheel is therefore no longer the level of one according to the invention Abutment on which an area of the saw blade located near the tooth base rests, but the plane of the center of the saw blade .

This has the effect, which at first appears to be undesirable, that the finish-ground teeth are in the axial runout afflicted areas of the saw blade are arranged asymmetrically with respect to these areas. It is essential, however, that all teeth sharpened according to the method according to the invention in relation to the central plane laid by the center of the saw blade are arranged symmetrically. This central plane is the only decisive factor in operation, as the saw blade in every sawing machine is stretched exclusively in its center. Although at

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a circular saw sharpened according to the method according to the invention, the axial runout errors in the saw blade remain unchanged remain, all teeth describe exact flight circles. As a result, such a circular saw creates a kerf, whose Width corresponds to the tooth width, so it is not undesirably large; as a result, that is also required by the circular saw Drive power and the volume cut on the workpiece not greater than necessary; furthermore, the circular saw does not the tendency to run and it creates smooth cut surfaces.

To carry out the method according to the invention are suitable known saw sharpening machines with a mandrel on which the center of the saw blade can be attached, one next to the saw blade in the vicinity of the tooth root circle arranged abutment and one opposite the abutment on the other side of the saw blade movably arranged clamping jaw for pressing the saw blade against the abutment. According to the invention is such Saw sharpening machine further developed in that the mandrel is a component is an axially immovable mounting for the saw blade and the abutment is at least approximately normal to the plane of the Saw blade adjustable and by means of a locking device working in time with the saw sharpening machine in one of the Axial runout of the saw blade corresponding position can be determined.

In one embodiment of the saw sharpening machine according to the invention the abutment is biased by a spring towards the saw blade. The feather is preferably so weak that it is just able to overcome frictional forces that result in an adjustment of the locking device when the locking device is released Oppose the abutment against the face of the saw blade.

It is advantageous to compensate for the force of the spring compensating for the abutment in that the clamping jaw is biased towards the saw blade by an equally strong spring counteracting the spring of the abutment. This succeeds it, the saw blade cross-cut in the stuck area

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to leave completely unchanged, provided that the inevitable frictional forces involved in movement of the Oppose the abutment on the one hand and the clamp jaw on the other hand, their amount are equal.

In another embodiment of the saw sharpening machine according to the invention a motor is provided for adjusting the abutment, which is controlled by a position of the saw blade in the area of the To be sharpened tooth measuring and with the position of the abutment comparing control device is controlled.

The last-described embodiment can thereby be developed further be that of the control device another motor for adjusting a jaw carrier carrying the jaw is controlled.

The invention is explained in more detail below with reference to schematic drawings of exemplary embodiments. It shows:

1 shows an only partially drawn axial section through a shaft bearing of a sawing machine with a circular saw sharpened according to the method according to the invention;

2 shows an axial section, which is also only partially drawn by a saw sharpening machine according to the invention a circular saw;

FIG. 3 shows a partial section corresponding to FIG. 2 through a another embodiment of a saw sharpening machine according to the invention; and

FIG. 4 shows a cross section along the line IV-IV in FIG.

In Figure 1, a bearing housing 11 is shown with two ball bearings 12 of a sawing machine, in which a drive shaft is axially immovable. The drive shaft 13 has a collar 14 with a centering shoulder 15 and one with the

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Collar screwed clamping disc 16 on. Between the federal government 14 and the clamping disk 16 is centered on the centering shoulder 15, the center 17 of a saw blade 18 of a circular saw clamped. The circular saw has teeth 19 equipped with hard metal plates.

The saw blade 18 is completely flat only in the area of its center 17, but further outside it deviates from the plane of its center 17 in the axial direction; it has an axial runout P of varying sizes along the circumference of the saw blade, so that the The saw blade makes a slightly tumbling motion during operation. Despite the axial runout P, the teeth 19 are symmetrical to the center plane Z of the center 17 is arranged so that the axial run-out is not noticeable when sawing; the teeth 19 create a Cutting kerf S, the width of which corresponds to the face width. This compensation of the axial runout P results from the fact that the teeth be sharpened on a saw sharpening machine according to Fig. 2 to 4.

In FIG. 2, the saw blade 18 is cut in an axial plane in which it is free from axial runout, that is to say completely flat. The saw sharpening machine shown in Figure 2 has a housing 21 with bearings 22 in which a mandrel 23 is axially immovable. The mandrel 23 has a collar 24 with a centering shoulder 25 and a clamping disk screwed to the collar 24. Between the collar 24 and the clamping disk 26, _r is centered on the centering shoulder 25, and the center 17 of the saw blade 18 is clamped. The clamping of the circular saw on the saw sharpening machine corresponds exactly to the clamping during operation on the sawing machine. It is particularly important that the center 17 of the saw blade 18 is also precisely defined in the axial direction on the saw sharpening machine.

On the housing 21 of the saw sharpening machine, a grinding wheel 28 is in the usual and therefore not shown manner Sharpening the teeth 19 guided up and down movable. The grinding wheel 28 is adjustable in such a way that it successively breasts,

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Can grind back and flanks of the teeth 19 and if necessary the teeth can also beveled, as indicated in FIG Incisors is common. For the compensation of plan impact errors P it is important that the management of the Grinding wheel 28 or a ram on which it is mounted on the machine frame 21 on the one hand and through the axially fixed mounting of the mandrel 23, on the other hand, a fixed axial assignment of the grinding surface of the grinding wheel and the center plane Z. of the saw blade 18 especially when grinding the flanks 29 of the teeth 19 is given.

For the compensation of the axial runout P it is also important that the areas of the saw blade 18 affected by the planar runout the saw sharpening machine cannot be bent flat, i.e. not forced are to assume a position in which these areas are arranged symmetrically to the center plane Z of the center 17, because the bending stresses introduced into the saw blade 18 lead to the saw blade returning to its original axial runout accepts as soon as it is released.

If the saw blade 18 is to be kept free from bending forces when the teeth 19 are sharpened, it is necessary to to clamp the saw blade in each case in the area radially inside the tooth 19 which is to be ground, so that it cannot evade the forces exerted on the tooth by the grinding wheel 28.

An embodiment of a clamping device that this apparently satisfies contradicting requirements, is shown in Fig.2. The clamping device includes a protruding from the housing 21 Arm 41 with a slot 42 through which the saw blade 18 protrudes. The arm 41 has a parallel to the axis of rotation of the mandrel 23 Guide 43, which is interrupted by the slot 42. In one part of the guide 43 on the left in FIG. 2 there is an abutment support 44 slidably guided. The abutment carrier 44 i

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a threaded bore 45 parallel to the guide 43 and thus also to the axis of rotation of the mandrel, into which a threaded bolt 46 is screwed is. The threaded bolt 46 carries an abutment 47 which rests on the saw blade 18. Between the abutment 47 and the housing 21 a spring 48 is clamped, the force of which is just enough, to overcome the friction of the abutment carrier 44 in the guide 43 and thus the abutment 47 in Figure 2 to the right to follow up when the saw blade 18 has an axial runout to the right. The abutment carrier 44 can be fixed with a locking device 49 in the guide 43. The locking device 49 is a hydraulic or in the example shown pneumatic piston-cylinder unit; but it could also, for example be designed as a mechanical or electromagnetic locking device. It is only essential that the locking device 49 is able to tighten the abutment carrier 44 and thus also the abutment 47 so strongly that the abutment when sharpening each tooth 19, the saw blade 18 in one Holds position that it would assume in the area of the tooth in question unaffected by external forces.

Opposite the abutment 47 is in the right part of FIG Guide 43 a jaw carrier 54 out. The clamping jaw carrier 54 has a cylinder bore 55 parallel to the guide 43 in which a piston 56 is guided. The piston 56 carries a jaw 57, the task of which is between itself and the abutment 47 to clamp the saw blade 18 whenever a tooth has been brought into a position by turning the saw blade 18 is in which the grinding wheel 28 is to machine the tooth. the Clamping jaw 57 is constantly under the slight bias of a spring 58, which the spring 48 via the abutment 47 on the Saw blade 18 compensates for the pressure exerted and thus ensures that the saw blade 18 in the area of the abutment 47 and the clamping jaw 57 always assumes the same position that it would assume without the abutment and the clamping jaw.

The jaw support 57 is normally by means of a screw 59 clamped in guide 43; however, he is after loosening

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this screw can be adjusted along the guide 43 if necessary is to adapt the jaw 57 to a thicker or thinner saw blade 18. A corresponding adjustment of the abutment 47 is possible in that the threaded bolt 46 is screwed more or less far into the threaded bore 45.

The saw sharpening machine shown in Figure 2 works as follows :

When the grinding wheel 28 has performed a grinding stroke on a tooth, for example in accordance with FIG , which can be designed in the usual way, rotated further by one or more tooth pitches, so that a new tooth 19 comes into the working area of the grinding wheel 28. During the advance, the locking device 49 is released and the cylinder bore 55 is depressurized, so that the abutment 47 and clamping jaw 57 lightly rest against the saw blade 18 only under the slight pressure of the springs 48 and 58 and follow this in the axial direction when the saw blade is in the area of the Tooth 19 now coming into the working position has an axial runout P. Now the locking device 49 is put under pressure _and thereby the abutment carrier 44 with the abutment 47 is fixed in its position. The cylinder bore 55 is then put under pressure and the saw blade 18 is firmly clamped between the abutment 47 and the clamping jaw 57. The grinding wheel now guides 28 a working stroke and then a return stroke, whereupon the working cycle described is repeated with a further tooth 19.

The saw sharpening machine shown in Fig. 3 and 4 differs differs from that shown in FIG. 2 in that the position of the abutment 47 and the clamping jaw 57 are controlled by a control device is adapted to the axial run-out of the saw blade 18 without the saw blade being subjected to forces that affect its axial run-out could falsify. According to Figure 3, the abutment support 44 is in the same way as in the embodiment of Figure 2 along the

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Guide 43 adjustable and can be clamped in the guide with a locking device 49. For a rough adjustment of the abutment 47 with respect to the abutment carrier 44, as in FIG. 2, a threaded bore 45 can be provided in the abutment carrier 44 be, into which a threaded bolt 46 can be screwed to a greater or lesser extent.

In the foot of the abutment support 44 is a threaded spindle according to Figure 3 61 screwed in, which extends parallel to the guide 43 and by a stepping motor 62 via a reduction gear 63 is drivable. The stepping motor 62 is controlled by a control device, the essential components of which are two differential sensors 64 and 65 and an actuator amplifier 66 are. The differential sensors 64 and 65 can be of any known type Be of construction; they can work electroinductively or pneumatically, for example. Your job is to give a signal when the saw blade 17 in the area that they scan without contact, namely in the area immediately radially inside the tooth 19 to be sharpened, has an axial runout.

In a corresponding manner to the abutment carrier 44, the clamping jaw carrier 54 can also be adjusted by means of a threaded spindle 71 which extends parallel to the guide 43 and can be driven by a stepping motor 72 via a reduction gear 73 is. The stepper motor 72 is also controlled by the differential sensors 64 and 65 controlled by the actuator amplifier 66. In addition, the jaw carrier 54 is also hydraulic or pneumatic cylinder designed as in Figure 2; the clamping jaw thus also receives its in the embodiment according to FIGS. 3 and 4 Clamping force from a hydraulic or pneumatic piston 56. To fix the clamping jaw carrier 54, according to FIGS. 3 and 4 a locking device 79 may be provided which, as shown, as a pneumatic or hydraulic piston-cylinder unit or can for example be designed as an electromagnetic device.

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In the case of the saw sharpening machine shown in FIGS the threaded spindles 61 and 71 are each rotated after sharpening a tooth 19 so that the abutment 47 and the Clamping jaw 57 are moved far enough away from the saw blade 18 that they do not touch this even if it is in the area of the the next tooth to be sharpened shows a strong axial runout. This next tooth is made in the usual way by turning the Saw blade 18 brought into its working position and then the abutment 47 and the clamping jaw 57 by turning the threaded spindles 61 and 71 so far moved towards the saw blade 18 that they just touch this, without its position between the Differential sensors 64 and 65. After this adjustment, the abutment carrier 44 and the jaw carrier 54 with the associated locking device 49 or 79 clamped in the guide 43. A clamping force is then applied to the clamping jaw 57 applied, which not necessarily, as shown in Figure 2, a needs to be hydraulic or pneumatic force, but could also be an electromagnetic force, for example. Essential is that the abutment 47 is not adjusted under the action of the clamping force and consequently the saw blade 18 in the area of the tooth to be sharpened 19 maintains its axial runout. Now the tooth is ground again in such a way that it has a face run-out is free, regardless of the axial runout of the area of the saw blade 18 that supports it.

If the clamping jaw 57 is designed so that, if the pneumatic, hydraulic or electromagnetic, for example, is omitted Clamping force is adjustable with almost no resistance in relation to the clamping jaw carrier 54, then the clamping jaw carrier 54 as well as in Figure 2 with a given thickness of the saw blade 18 be clamped in a certain position in the guide 43? the threaded spindle 71, the stepping motor 72 and the reduction gear 73 can then be omitted. But in practice there is a certain one Resistance of the jaw 57 to any movement with respect to the jaw support 54 is inevitable, it becomes at high Requirements for the freedom from chipping of the sharpened teeth 19

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preferred, the abutment carrier 54 together with the abutment 57 with each advance movement of the saw blade 18 from the saw blade away, so that its plan view for the differential sensor 64 and 65 can be seen in full size and leads to a corresponding adjustment of the abutment 47.

Expectations:

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Claims (6)

DR. ING. F. WUESTHOFF S NCUKrU) O ⁽ ° ^{80) ββ 2} ° " DH. ING. D. BEHRENS ^τ ™ - "°" ⁽ ° ^{80) ββ 2} ° " TKLKX 5 24 070 I) IPl .. ING. R. GOETZ TKLKGItAMMK I PATENTANWÄLTE protectpatent mOnchkm 1A / G-46 057 Claims Μ ·) Method for sharpening circular saws whose teeth are thicker than their saw blade, which is rotatably mounted in its center and is clamped in an area near the root of a tooth before a grinding wheel moves along this tooth is, characterized in that when clamping the given when the saw blade (18) is relaxed, with an axial runout (P) afflicted with maintaining the axial position of the clamped area in relation to the center (17) of the saw blade and the movement of the grinding wheel (28) is carried out regardless of the axial run-out according to the axial position of the center will. 2. Saw sharpening machine to carry out the method according to Claim 1, with a mandrel on which the center of the saw blade can be stacked, one next to the saw blade in the vicinity of the tooth root circle arranged abutment and one opposite the abutment movably arranged on the other side of the saw blade Clamping jaw for pressing the saw blade against the abutment, characterized in that the mandrel (23) Part of an axially non-displaceable bearing for the saw blade (18), and the abutment (47) at least approximately Can be adjusted normal to the plane of the saw blade and by means of a locking device that works in time with the saw sharpening machine (49) can be determined in a position corresponding to the axial runout (P) of the saw blade. 609886/0242 / ² 46 057 - r- 3. saw sharpening machine according to claim 2, characterized in that the abutment (47) by a spring (48) is biased towards the saw blade (18). 4. saw sharpening machine according to claim 3, characterized in that the clamping jaw (57) of one of the spring (48) of the abutment (47) counteracting, equally strong spring (58) towards the saw blade (18) is biased. 5. saw sharpening machine according to claim 2, characterized in that a for adjusting the abutment (47) Motor (62) is provided which controls the position of the saw blade (18) in the area of the tooth (19) to be sharpened and comparing it with the position of the abutment (47) (64-66) is controlled. 6. A saw sharpening machine according to claim 5, characterized in that another of the control device (64-66) Motor (72) for adjusting a jaw (57) carrying jaw carrier (54) is controlled. 609886/0242 Blank page