JPS60112401A - Stretcher for band sawing machine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a tensioning device for a bandsaw machine used for cutting wood such as lumber and wood I.

(B) Prior Art Conventionally, as a band saw machine, an endless band saw is installed between a plurality of steel wheels, and the steel wheel is rotated and the rotation is transmitted to the steel band by frictional force to drive the steel band. It is known that this was done. Such a band saw machine is provided with a tensioning device for keeping the tension force of the band saw constant and preventing the occurrence of sawing and bending.

Conventionally used tension devices include the first
A lever as shown in the figure is generally used. That is, a lever b is integrally and rotatably fixed to the center of the support shaft a, and a weight C is suspended from a force point A provided at the tip of the lever b. In addition, a knife f is provided at the inverted V-shaped receiving portion a' provided below both ends of the support shaft a, and protrudes perpendicularly from the support member e fixed to the support column d in the direction 1-.
It is supported by engaging the L-shaped part. On the other hand, a V-shaped receiving portion a'' is provided above the support shaft a, and a protruding rod g is provided with its lower end engaged with the receiving portion a''. Further, the lower end of the bearing j of the steel wheel i on the driven side on which the band saw is stretched, the two ends of the lot g being supported by the north end of the support d so as to be freely movable in the radial direction. is brought into contact with the contact point C at contact position C. Further, one end of the bearing part j is rotatably supported at one end of the support d about the rotation center 0', and a steel wheel i is rotatably supported by the bearing part i about the axis. It is supported by The support column d is movable up and down, and is used to position and support the steel wheel i through a bearing j at a position where the band saw is to be stretched.

If it is like this, the force W of the weight C applied to the force point A
becomes the standard biasing force, and the contact position O between the receiving part a' and the knife f is used as a fulcrum, and the above-mentioned receiving part a''' and the upward rod g
The force is amplified by the distance ratio AO10B and is transmitted to the corresponding contact position B by a force that is amplified by the distance ratio AO10B. Part j is biased, and the biasing force applied by lever II, whose force point is C1 and the fulcrum is Oo, and the point of action is D, is further amplified by 0'C10''D, and the steel wheel i is moved in the radial direction around the axis. It is possible to apply a force in the direction of increasing the distance between the side axles, and to apply a constant tension force to the gauge saw.At this time, the reaction force against the bias force and the reference force applied by the weight C can be In Fig. 2, WO is a constant mainly determined by the weight of the steel wheel i and the lever b.Then, the distance #AO between the force point A and the fulcrum 0, and the fulcrum O and the point of action. Since the ratio of the distance between #8 and the distance #OB is basically H-foot, and the ratio between the distances 0°C and O'D is also constant, the tension force should always be constant.However, In reality, such a device has the disadvantage that the tension changes as described below, and as a result, bending, cracking, and breakage of the band saw are likely to occur.

The inventor of the present invention investigated the cause of the change in the A force and found that it is due to the following causes. That is, as shown in FIGS. 3 (1) to (4) and FIG. is actually formed in a rounded shape rather than a pointed shape so that it can handle heavy loads. Therefore, the distance between the side axles is due to the rotation of the lever b when first positioning the lever b, the sliding of the band saw due to the thermal expansion of the band saw while the band saw is driving, the pressing force of the object to be cut, etc. As a result of the rotation of the lever b due to the change of As the distance changes, the distance ra between the point of effort A and the fulcrum 0, and the ratio AO10B between Ao and the distance OB between the fulcrum O and the point of action 8 change.Furthermore, the point of effort, the fulcrum, and the point of action are not aligned in a straight line. This also has an effect, and therefore the biasing force changes.

In Fig. 4, T indicates the tension force of the band saw, X indicates the position (height) of the tip of the cutter, and the numbers ■, 2.3.4
3 shows actual measurement examples of the position of the tip of lever b and the tension force in FIGS. 3(1), (2), (3) and (4), respectively.

(c) Purpose Based on the above-mentioned research results, the present invention provides a band saw by always keeping constant the ratio of the distance between the force point and the fulcrum and the distance between the fulcrum and the point of action and by arranging these three points on a straight line. To provide a tensioning device for a bandsaw machine which can always keep the tension applied to a constant constant and eliminate inconveniences such as bending, cracks and breakage of the band saw.

(D) Structure In order to achieve the above object, the present invention provides that the proximal end of the lever is supported rotatably around the axis of a support shaft, and
A rotating lever having a point of force at its tip, and a rotating lever provided so as to be able to rotate integrally with the rotating lever, the axis of which is offset by a certain distance with respect to the axis of the supporting shaft. and an eccentric cam in which the force point, the fulcrum, and the point of action are arranged in a straight line, and the reaction force generated by biasing the specific chain wheel in the radial direction is applied to the axis of the eccentric cam. The specific side wheel is applied to the outer periphery of the eccentric cam along the line of action passing through the center, and a certain reference force is applied to the force point of the rotating cam, using the lever. It is characterized in that the biasing force against the band saw is balanced with the tension force of the band saw.

(e) Examples Embodiments of the present invention will be described below with reference to the drawings.

Embodiment 1 (FIGS. 5 and 6) Bearings 2 each having an alignment function are provided on two struts l corresponding to the struts d in the conventional example, and these bearings 2
A support @3 is provided with each end rotatably supported. A rotary lever 4 is disposed in the center of the support shaft 3, with the base end 4a fixed thereto, so as to be rotatable together with the support shaft 3 about the axis 01 of the support shaft 3. ing. Furthermore, a weight 5 with a predetermined heavy edge is suspended from a force point A provided at the tip end 4b of the rotary lever 4.

10,000, the axis 0 of the support shaft 3 is located near both ends of the support shaft 3.
1, and deviate the axis o2 by a certain distance from A, 0.
Disk-shaped eccentric cams 6 are provided for arranging the cams 1 and 02 in a straight line. A ring-shaped lower end 7a of a protrusion rod 7 disposed substantially perpendicularly above the axis 02 is rotatably fitted onto the outer periphery of the eccentric cam 6 via a hair ring 8. Furthermore, the upper end of this projecting rod 7 is brought into contact with a bearing part of a chain wheel (not shown) on which a band saw is stretched. The upper end of the support column 1 is supported at a position where a chain wheel is stretched, as in the conventional example, and also serves as a support for the lever II.

With such a device, the rotation/pulling 4, the support shaft 3 and the eccentric cam 6 rotate together, and the axis O1 of the support shaft 3
However, since the axis o2 of the eccentric cam 6 is deviated by a certain distance and A, 01.02 is on a straight line, the force (reference biasing force) of the weight 5 applied to the force point A is applied with the axis 01 as the fulcrum. The force is amplified and transmitted to the axis o2 by the distance ratio AOI10102, and the axis 02 becomes the point of action, and the transmitted force causes the eccentric cam 6 to press the uplift rod 7 in the direction of pushing -1-. In response to this pressing force, the rod 7 on the line of action of the force urges the chain wheel in the direction of increasing the distance between the steel wheels, which is further amplified by a lever II (not shown) and is applied to the band saw. Apply a predetermined tension. In this state, the reaction force applied to the outer periphery of the eccentric cam 6 along the axis 02 of the eccentric cam 6 and the reference urging force applied to the force point by the weight 5 are balanced.

At this time, even if the rotating lever 4 rotates due to various causes, the position of the axis 01 remains constant, the distance between the axis O1 and 02 is also constant, and A, 01.02 is straight 11! ]2, the distance ratio AOI 10102 does not change. Therefore, the biasing force on the chain wheel is always constant, so the above? ? i: A constant tension can be applied to the saw at all times.

In this way, according to this embodiment, it is possible to always apply a constant tension force to the band saw, thereby eliminating the inconveniences that occur in the conventional saw, such as bending and cracking or breaking of the band steel due to changes in tension force. can do.

Embodiment 2 (FIGS. 7 and 8) Each end of a support shaft 12 is rotatably supported by one end of two support columns 11 with an alignment function, and each end of the support shaft 12 is rotatably supported. A base end 13a of a rotating arm 13 is integrally fixed to the end so as to be rotatable, and a weight 14i is suspended from the tip 13b of the rotating arm 13. On the other hand, an eccentric cam 15 is provided at the center of the support shaft 12.
The axial center 02' is offset by a certain distance from the axial center 01' of the support shaft 12, and the eccentric cams 13b, 01', and 02' are arranged and fixed in a straight line, and the eccentric cam 15 is fixed.
On the outer circumference, ¥l? A steel wheel 17 on which fjN16 is stretched is rotatably fitted via a hair ring 18.

If this is the case, the tip 1 of the rotating arm 13
3b becomes the force point A, the axial center O1° of the support shaft 12 becomes the fulcrum, and the axial center 02' of the eccentric cam 15 becomes the point of action, and as in the first embodiment, a constant tension force is always applied to the band saw 16. I can do it. Furthermore, according to this embodiment, since the projecting rod is not required, the number of parts can be reduced and the structure can be simplified.

Embodiment 3 Each end of a support shaft 22 is provided with an alignment function and rotatably supported at the upper ends of two pillars 21, and the base end of a rotating arm 23 is integrated with one end of the support shaft 22. A weight 24 is suspended from a force point A at the tip of the rotating arm 23. On the other hand, an eccentric cam 25 is provided at the center of the support shaft 22.
The axis 01'' is offset by a certain distance from the axis 02°'' of the support shaft 22, and A, O1'', and 02'' are arranged and fixed in a straight line, and the eccentric cam 25
A steel wheel 27 on which a band saw 26 is stretched is mounted on the outer circumference of the bearing 2
8 and is rotatably fitted. Note that the support shaft 2
2 uses a material that can withstand twisting for 1 minute.

In this case, the tip of the rotating arm 23 has a force point A, the axis 01'' of the support shaft 22 becomes the fulcrum, and the axis 02'' of the eccentric cam 25 acts as the point of action. As in Examples 1 and 2, a constant tension force can always be applied to the band saw 26. Furthermore, according to this embodiment, as in the above-mentioned embodiment 2, no projecting rod is required, so that the number of parts can be reduced and the structure can be simplified. In addition, according to this embodiment, the pivot arm 23
is fixed to only one end of the support shaft 22, so the structure is simpler than that of the second embodiment.

Note that the present invention is of course not limited to the above-mentioned embodiments, and the rotary lever is not limited to being rotatable integrally with the support shaft, and the eccentric cam may also be rotatable integrally with the support shaft. It is not limited to what is provided. In other words, the force point of the spindle rotates/flips around the axis of the spindle, and the axis of the eccentric cam is kept at a certain distance from the axis of the spindle, and the force point, fulcrum, and point of action are aligned in a straight line. It suffices as long as it rotates as one unit while being in the same position.

Furthermore, the rotating mechanism is not limited to that shown in the first and second embodiments.

Moreover, what provides the reference biasing force to be applied to the force point of the rotary lever is not limited to a weight, and may be, for example, fluid pressure.

Further, in a tensioning device provided with a protruding barb rod, the protruding barb rod is not limited to that shown in the first embodiment, and for example, as shown in FIG. The flat lower end surface 7a' of the protruding rod 7 is brought into contact with the uppermost end of the protruding rod 7, and the protruding rod 7 is supported by a support member 9 so as to be slidable downward. Good too. Furthermore, as shown in FIG.
It is also possible to fit the eccentric cam 6 into the lower end of the eccentric cam 6, and make the extreme end of the eccentric cam 6 come into contact with the flat top wall surface 7b of the recess. If so, the structure would be simpler and easier to implement than the one shown in Example 1.

In addition, various modifications can be made without departing from the spirit of the present invention.

(f) Effects As explained above, the present invention has the following advantages: By keeping the distance between the force point and the fulcrum and the distance between the fulcrum and the point of action always constant and keeping the point of force, the fulcrum, and the point of action always in a straight line, It is possible to provide a tensioning device for a bandsaw machine by always keeping the tension applied to the band saw constant and eliminating inconveniences such as sawn surfaces and cracks and breaks in the band steel.

[Brief explanation of drawings]

1 to 4 show conventional examples, and FIG. 1 is a schematic explanatory diagram;
Fig. 2 is an explanatory diagram of the action, Fig. 3 is an explanatory diagram showing changes in the positional relationship between the fulcrum and the point of application, and Fig. 4 is a graph showing the correlation between the position of the rotary lever and the tension force applied to the band saw. . Fifth
FIG. 6 shows an embodiment of the present invention, FIG. 5 is a schematic perspective view, and FIG. 6 is an enlarged view showing the main part. 7 and 8 show other embodiments of the present invention, with FIG. 7 being a schematic front view and FIG. 8 being a side view of the same. 9 and 1O show still other embodiments of the present invention, FIG. 9 is a schematic front view, and FIG.
Figure 0 is the same side view. 11 and 12 are enlarged views of main parts corresponding to FIG. 6 showing still another embodiment of the present invention. 3.12.22...Spindle 4.13.23...Rotating lever 5.14.24/φ skewer weight 5 6.15.25...Eccentric cam 7.7', 7'' umbrella・9 saw”-Rod 16.26・9 band saw 17.27・Steel car agent Patent attorney Hiroshi Akazawa 6

Claims (5)

[Claims] (1) A band saw machine is equipped with an endless band saw stretched between a plurality of steel wheels, and a specific steel wheel that can be freely movable in the radial direction is biased by a lever in a direction that increases the distance between the side axles. A device configured to apply tension to the lever, the lever being rotatably supported around the axis of a support shaft whose base end serves as a fulcrum, and having a point of force at its tip. Shihachi
and an eccentric cam which is provided so as to be able to rotate integrally with this rotation and whose shaft center serving as a point of action is offset by a certain distance with respect to the shaft center of the support shaft. The force point, the fulcrum, and the point of action are arranged in a straight line, and the reaction force generated by biasing the specific steel wheel in the radial direction is applied along the line of action passing through the axis of the eccentric cam. A constant reference biasing force is applied to the outer circumference of the eccentric cam at the same time as the force point of the rotating lever, and the biasing force against the specific steel wheel generated using the lever and the tension force of the band saw are A tensioning device for a bandsaw machine, characterized in that the tensioning device is balanced. (2) A projecting rod is attached to the eccentric cam so as to be rotatable with respect to the eccentric cam, and the saw axle is biased 4=j in the direction of increasing the distance between the side axles via the projecting rod. A tensioning device 9 for a bandsaw machine according to claim 1, characterized in that: (3) A specific steel axle is rotatably attached to the outer periphery of the eccentric cam, and the steel axle is biased in the direction of increasing the distance between the side axles. A tensioning device for a bandsaw machine according to item 1. (4) The steel strip according to claim 1, 2, or 3, characterized in that gravity acting on a weight acts as a reference biasing force on the force point of the rotary lever. Board tension device. (5) A force generated by a constant fluid pressure or other suitable means is applied to the force point of the rotary lever as a reference biasing force. A tensioning device for a bandsaw machine according to item 3.