Tooth for bucket of construction machine

Abstract

To provide a tooth for a bucket of a construction machine capable of reducing impact force bounced back from sediment upon excavation of the ground with the bucket, and suppressing wear of an excavation claw to allow extension of a replacement interval.SOLUTION: A cavity 26 formed in a base end of an excavation claw 20 is externally fitted on an adapter 19 welded on a tip edge 8a of the bucket 8. A lock pin 21 is arranged between an adapter side engaging surface 22a formed on the adapter 19 and a claw side engaging surface 27a formed on the excavation claw 20 to prevent the excavation claw 20 from dropping out from the adapter 19 and to allow position displacement in a longitudinal direction of the excavation claw 20. The excavation claw 20 is energized to a tip side through arrangement of an arc-like plate spring 33 in a plan view between a pressure application surface 31a formed in the cavity 26 of the excavation claw 20 and a pressure receiving surface 25a formed on a tip of the adapter 19.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a tooth for a bucket of a construction machine. [Background technology]

[0002] Conventionally, buckets of construction machines that excavate soil and sand on the ground are equipped with various teeth to suppress wear on the bucket body. These teeth consist of a number of adapters that are provided on the leading edge of the bucket body and protrude toward the leading end, and excavation tines that are detachably attached to these adapters and come into contact with the ground during excavation work. Since the excavation tines gradually wear out during excavation work, it becomes necessary to replace the excavation tines periodically, but this replacement work is a time-consuming and troublesome task for the worker.

[0003] For example, Patent Document 1 discloses a wear assembly in which an adapter is welded to the lip of a bucket of an earthwork machine and a wear member is detachably attached to the adapter via a lock. By integrating the lock with the wear member, the wear member can be easily replaced without the need for a hammer or the like. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-190271 A Summary of the Invention [Problem to be solved by the invention]

[0005] By the way, when a test was carried out simulating the behavior of the teeth digging the ground, it was found that even with the same digging behavior, when the soil grain size is large as shown in FIG. 10(b), the wear of the excavation claw progresses more quickly than when the soil grain size is small as shown in FIG. 10(a). Considering this mechanism, it is considered that the larger the soil grain size, the greater the impact force that bounces off the soil when the excavation claw excavates the ground, which promotes the wear rate of the excavation claw. Therefore, reducing this impact force leads to suppression of wear of the excavation claw, and ultimately to extension of the replacement interval of the excavation claw, thereby reducing the labor of the operator, but this was not possible with the technology of Patent Document 1.

[0006] The present invention has been made to solve such problems, and its object is to provide teeth for a bucket of a construction machine that can reduce the impact force that rebounds from soil and sand when the bucket is used to dig into the ground, thereby suppressing wear on the digging claws and extending the replacement interval. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, the tooth for a bucket of a construction machine of the present invention comprises a plurality of adapters provided on the leading edge of a bucket and shaped to protrude toward the leading end, and an excavation claw having a cavity formed on the base end side that opens toward the adapter and is removably attached by externally fitting the cavity onto the adapter, characterized in that the tooth for a bucket of a construction machine is provided with a connecting portion that prevents the excavation claw from falling off the adapter and allows the excavation claw to be displaced toward the leading end and the base end, respectively, and an elastic member that is interposed between the adapter and the excavation claw and elastically biases the excavation claw toward the leading end. Effect of the Invention

[0008] The bucket teeth of the construction machine of the present invention can reduce the impact force rebounding from soil and sand when the bucket is digging the ground, thereby suppressing wear on the digging claws and extending the replacement interval. [Brief description of the drawings]

[0009] [Figure 1] 1 is a side view showing a hydraulic excavator to which a bucket tooth according to an embodiment of the present invention is applied. [Diagram 2] FIG. [Diagram 3] FIG. 2 is an exploded perspective view showing a coupling relationship between an adapter and an excavation claw in the first embodiment. [Figure 4] 11 is a side cross-sectional view showing a process of connecting the excavating claw to the adapter by a lock pin. FIG. [Diagram 5] FIG. 11 is a side cross-sectional view showing the state in which the connection of the excavation claws has been completed. [Figure 6] 6 is a cross-sectional view taken along line IV-IV in FIG. 5, showing a state in which the connection of the excavation claws has been completed. [Figure 7] 7 is a cross-sectional view corresponding to FIG. 6, showing a state in which a leaf spring is disposed in a cavity of the excavation claw. [Figure 8] 6 is a cross-sectional view corresponding to FIG. 5, illustrating a state in which the leaf spring is bent by an impact force caused by excavation of the ground. [Figure 9] FIG. 7 is a cross-sectional view corresponding to FIG. 6, showing a state in which the leaf spring is bent by an impact force. [Figure 10] FIG. 1 is a schematic diagram showing a conventional technique when the grain size of the soil to be excavated is small (a), a conventional technique when the grain size of the soil to be excavated is large (b), and an embodiment when the grain size of the soil to be excavated is large (c). [Figure 11] 13 is a graph comparing the reaction forces in the cases (a), (b), and (c) over time. [Figure 12] FIG. 11 is an exploded perspective view showing a coupling relationship between an adapter and an excavation claw in a second embodiment. [Figure 13] 13 is a side cross-sectional view showing a state in which the connection of the excavation claw to the adapter is completed by the lock pin. FIG. [Figure 14] 14 is a cross-sectional view taken along line XIV-XIV in FIG. 13, showing a state in which the joining of the excavation claws has been completed. [Figure 15] 14 is a cross-sectional view corresponding to FIG. 13, showing a state in which the leaf spring is bent by an impact force caused by excavation of the ground. [Figure 16]FIG. 15 is a cross-sectional view corresponding to FIG. 14, showing a state in which the leaf spring is bent by an impact force. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] [First embodiment] Hereinafter, a first embodiment in which the present invention is embodied in a tooth for a bucket of a hydraulic excavator will be described. Fig. 1 is a side view showing a hydraulic excavator to which the bucket tooth of this embodiment is applied, and first, a schematic configuration of the hydraulic excavator will be described based on the same drawing. Note that in the following description, forward / backward, left / right, and up / down directions are expressed from the perspective of an operator riding on the hydraulic excavator.

[0011] A lower traveling structure 2 of the hydraulic excavator 1 is equipped with crawlers 3, and the crawlers 3 are driven by a hydraulic traveling motor (not shown) to travel the hydraulic excavator 1. An upper rotating structure 4 is provided on the lower traveling structure 2, and the upper rotating structure 4 is driven to rotate by a hydraulic rotating motor (not shown). A multi-jointed work front 5 is provided in front of the upper rotating structure 4, and the work front 5 is composed of a boom 6, an arm 7, and a bucket 8. The angle of the boom 6 is changed by a boom cylinder 14, the angle of the arm 7 is changed by an arm cylinder 15, and the angle of the bucket 8 is changed by a bucket cylinder 16.

[0012] An operator's cab 10 in which an operator sits is provided at the front on a frame 9 of the upper rotating body 4, and a fuel tank 11, a machine room 12, a counterweight 13, etc. are provided behind the operator's cab 10 on the frame 9. Although not shown, a hydraulic pump driven by an engine is mounted in the machine room 12, and the hydraulic pump is connected to the above-mentioned traveling and swinging hydraulic motors and each of the cylinders 14 to 16 of the front work unit 5 via hydraulic piping, and operates each hydraulic actuator in response to the operation of the operator.

[0013] Fig. 2 is a perspective view showing a single bucket 8. Since the posture of the bucket 8 changes in various ways depending on the operating state of the front work unit 5, the configuration of the bucket 8 will be described assuming that the bucket 8 is in a posture in which the tips of the teeth 18 shown in Fig. 2 are directed rearward. 2, the leading edge 8a of the bucket 8 faces rearward, and the leading edge 8a is provided with a plurality of teeth 18 arranged side by side in the left-right direction. Each tooth 18 consists of a plurality of adapters 19 provided on the leading edge 8a of the bucket 8, and an excavation claw 20 detachably attached to each adapter 19 via a lock pin 21 (corresponding to the connecting portion of the present invention).

[0014] FIG. 3 is an exploded perspective view showing the connection between the adapter 19 and the excavation claw 20. Although a specific tooth 18 is shown in this figure, the other teeth 18 have the same structure. The base end of adapter 19 is welded to the leading edge 8a of bucket 8, and the leading end of adapter 19 protrudes rearward. On the right side of the base end of adapter 19, an engagement groove 22 having a square cross section is provided extending in the vertical direction, and the flat surface inside engagement groove 22 facing the front side (corresponding to the base end side of the present invention) is an adapter side engagement surface 22a (corresponding to the connecting portion of the present invention).

[0015] The portion of the adapter 19 in front of the engagement groove 22 is formed by upper and lower stabilizing surfaces 23a, 23b and both left and right side surfaces 24a, 24b, and the left and right side surfaces 24a, 24b are planar and parallel to each other. The upper stabilizing surface 23a is generally planar and faces upward, and the lower stabilizing surface 23b is generally planar and faces downward, and they gradually approach each other toward the rear and are connected via the pressure receiving portion 25. As a result, the portion of the adapter 19 in front of the engagement groove 22 is generally triangular and symmetrical about the axis L in the side view shown by the arrow A in FIG. 3, and generally square and symmetrical about the axis L in the plan view shown by the arrow B in FIG. The pressure receiving portion 25 is rectangular and protrudes toward the rear, and a pressure receiving surface 25a is formed at the tip of the pressure receiving portion 25, which is planar and faces backward.

[0016] The excavation claw 20 is disposed at the rear of the adapter 19, and has a shape in which its tip protrudes rearward. A cavity 26 that opens toward the adapter 19 is formed at the base end of the excavation claw 20, and the excavation claw 20 is attached in a position in which the cavity 26 is fitted onto the adapter 19, as will be described in detail later. An engagement groove 27 having a rectangular cross section is provided on the right side of the base end of the excavation claw 20, extending in the vertical direction, and a pair of upper and lower flat surfaces facing the rear side (corresponding to the tip side of the present invention) in the engagement groove 27 are claw-side engagement surfaces 27a (corresponding to the connecting portion of the present invention). In a plan view, the claw-side engagement surfaces 27a face each other at a predetermined interval in front of the adapter-side engagement surface 22a, and a lock pin 21 is disposed between the respective engagement surfaces 22a, 27a.

[0017] Figure 4 is a side cross-sectional view showing the process of connecting the excavation claw 20 to the adapter 19 using the lock pin 21, Figure 5 is a side cross-sectional view showing the state after the connection of the excavation claw 20 has been completed, and Figure 6 is a cross-sectional view taken along line IV-IV in Figure 5 showing the state after the connection of the excavation claw 20 has been completed. As shown in Figs. 3 and 4, the lock pin 21 is generally rod-shaped extending in the vertical direction, and is formed by joining the rear outer member 21a and the front inner member 21b via the rubber 21c, and a pair of upper and lower step portions 21ba are formed on the front surface of the inner member 21b. When the lock pin 21 receives a compressive force in the front-rear direction, it can be compressed and deformed while bending the internal rubber 21c. As shown in Figs. 5 and 6, such a lock pin 21 is inserted between the claw side engagement surface 27a and the adapter side engagement surface 22a, and the outer member 21a abuts against the adapter side engagement surface 22a, and the upper and lower parts of the inner member 21b abut against the claw side engagement surface 27a of the excavation claw 20. In addition, the upper and lower step portions 21ba of the inner member 21b are engaged with the claw side engagement surface 27a, respectively, thereby preventing the lock pin 21 from coming off in the vertical direction. Such a lock pin 21 prevents the digging claw 20 from falling off the adapter 19, and also provides play equivalent to the gap S as shown in FIG. 5, allowing the position of the digging claw 20 to be displaced rearward.

[0018] On the other hand, as shown in Figures 3, 5, and 6, the cavity 26 of the excavation claw 20 is formed by upper and lower stabilizing surfaces 29a, 29b and both left and right side surfaces 30a, 30b, and both left and right side surfaces 30a, 30b are parallel to each other in planar shape. The upper stabilizing surface 29a is substantially planar facing downward, and the lower stabilizing surface 29b is substantially planar facing upward, and gradually approaches toward the rear and is connected via the spring accommodating chamber 31. As a result, the excavation claw 20 is substantially triangular in shape with vertical symmetry about the axis L in a side view, and substantially rectangular in shape with horizontal symmetry about the axis L in a plan view. When the excavation claw 20 is attached to the adapter 19, the left and right side surfaces 30a, 30b in the cavity 26 face the left and right side surfaces 24a, 24b of the adapter 19 with a small gap therebetween. In addition, the upper and lower stabilizing surfaces 29a, 29b of the excavation claws 20 face the upper and lower stabilizing surfaces 23a, 23b of the adapter 19, and as will be described in detail later, are adapted to separate and abut in accordance with the positional displacement of the excavation claws 20 in the forward / backward direction.

[0019] The spring accommodating chamber 31 is rectangular and extends to the left and right beyond the left and right side surfaces of the cavity 26, and has a pressure surface 31a facing forward. When the excavation claw 20 is attached to the adapter 19, the pressure-receiving portion 25 of the adapter 19 is disposed in the spring accommodating chamber 31 of the excavation claw 20, and the pressure-receiving surface 25a and the pressure surface 31a face each other with a predetermined gap therebetween.

[0020] A leaf spring 33 (corresponding to the elastic member of the present invention) is disposed between the pressure receiving surface 25a and the pressure applying surface 31a in the spring accommodating chamber 31. The leaf spring 33 is made of an elastic metal plate and has a rectangular plate shape extending left and right, and is curved in a plan view so as to be concave toward the pressure applying surface 31a, in other words, the tip side of the excavation claw 20, and convex toward the base end side of the excavation claw 20, in other words, the pressure applying surface 31a. The center portion 33b of the leaf spring 33 elastically abuts against the pressure receiving surface 25a, and the left and right end portions 33a of the leaf spring 33 elastically abut against the pressure applying surface 31a, respectively, thereby biasing the adapter 19 and the excavation claw 20 in the direction away from each other. As a result, the biasing force of the leaf spring 33 acts to displace the excavation claw 20 rearward. As shown in Figures 5 and 6, the positional displacement of the excavation claw 20 is regulated by the adapter 19 via the lock pin 21, so that the excavation claw 20 is maintained in the rearmost position, in other words, the most protruding position, and the stabilization surfaces 29a, 29b on the excavation claw 20 side and the stabilization surfaces 23a, 23b on the adapter 19 side are spaced apart from each other.

[0021] The leaf spring 33 is made of a material that is less hard than the excavation claw 20, in other words, a material that is more easily worn than the excavation claw 20. The vertical width of the leaf spring 33 is set to be approximately 1 mm smaller than the vertical width inside the spring accommodating chamber 31. However, this is not limited to this, and the material of the excavation claw 20 and the vertical widths of the leaf spring 33 and the spring accommodating chamber 31 can be changed as desired.

[0022] In the tooth 18 configured as above, the replacement work of the worn digging claw 20 is carried out in the following procedure. 7 is a cross-sectional view corresponding to FIG. 6, showing the state in which the leaf spring 33 is disposed in the cavity 26 of the excavation claw 20. First, a new leaf spring 33 is disposed in the spring accommodating chamber 31 of a new excavation claw 20. As shown by the dashed line in FIG. 7, the leaf spring 33 in a plan view has a gentle arc shape even when no load is applied, and the leaf spring 33 is compressed and deformed from the left and right directions and then disposed in the spring accommodating chamber 31 through the cavity 26. When the compression force is released, both left and right end portions 33a of the leaf spring 33 abut against the pressure surface 31a, and two points on the front surface of the leaf spring 33 slightly closer to the center than the left and right end portions 33a abut against the left and right corner portions 31b of the spring accommodating chamber 31, respectively. If the angle between two straight lines connecting the center of the arc of the leaf spring 33 and both ends of the leaf spring 33 when no load is applied is defined as α, then the angle α will decrease to angle β after the leaf spring 33 is disposed in the spring accommodating chamber 31. With the above, the installation work of the leaf spring 33 to the excavation claw 20 is completed.

[0023] 5 is struck from above with a hammer, the internal rubber 21c and the leaf spring 33 in the spring accommodating chamber 31 are deflected, and the lower step 21ba of the lock pin 21 climbs over the lower claw-side engagement surface 27a, causing the lock pin 21 to fall out downward. Since the lock pin 21 is no longer preventing the digging claw 20 from falling out, the worn digging claw 20 and the internal leaf spring 33 can be removed from the adapter 19.

[0024] Then, the new excavation claw 20 with the leaf spring 33 attached is attached to the adapter 19, the lower part of the lock pin 21 is inserted between the claw side engagement surface 27a and the adapter side engagement surface 22a, and the lock pin 21 is then hammered in from above. As shown by the arrows in Fig. 4, the rubber 21c in the lock pin 21 and the leaf spring 33 are deflected, while the lower step 21ba of the lock pin 21 climbs over the upper claw side engagement surface 27a, and as shown in Fig. 5, the lock pin 21 is sandwiched between the engagement surfaces 22a, 27a to prevent the excavation claw 20 from falling off. This completes the replacement work for the excavation claw 20.

[0025] Next, the action of the bucket tooth 18 of this embodiment will be described. FIG. 8 is a cross-sectional view corresponding to FIG. 5, showing a state in which the leaf spring 33 is bent due to an impact force accompanying excavation of the ground, and FIG. 9 is a cross-sectional view corresponding to FIG. 6, showing a state in which the leaf spring 33 is bent due to the impact force.

[0026] During excavation, the bucket 8 collides with the ground and receives a reaction force F, which is input to the excavation claw 20 as an impact force bouncing back from the soil. Receiving the component of the impact force in the front-rear direction, the excavation claw 20 starts to move forward from the state shown in Figs. 6 and 7, and the leaf spring 33 starts to bend accordingly. More specifically, the leaf spring 33 is compressed in the front-rear direction and expands in the left-right direction while both left and right ends 33a are in sliding contact with the pressure surfaces 31a of the spring accommodating chamber 31. Therefore, the impact force at this time is transmitted to the adapter 19 side while bending the leaf spring 33. The expansion of the leaf spring 33 is permitted by the spring accommodating chamber 31 which is expanded left and right.

[0027] As the excavation claw 20 is displaced forward, the stabilizing surfaces 29a, 29b on the excavation claw 20 side and the stabilizing surfaces 23a, 23b on the adapter 19 side gradually approach each other and come into contact with each other at some point as shown in Figs. 8 and 9. The subsequent impact force is directly transmitted from the excavation claw 20 to the adapter 19 side via the stabilizing surfaces 29a, 29b, 23a, 23b, without passing through the leaf spring 33. When the bucket 8 finishes digging into the ground and the reaction force F disappears, the impact force input to the excavation claw 20 also disappears, and the excavation claw 20 is displaced backward by the elasticity of the leaf spring 33, returning to the state shown in Figs. 5 and 6. Every time the bucket 8 excavates the ground, the excavation claw 20 is displaced forward and backward through the above process, and the leaf spring 33 is deflected accordingly to transmit the impact force to the adapter 19 side.

[0028] Such an impact force input to the excavation claw 20 is proportional to the magnitude of the reaction force F received by the bucket 8 when it collides with the ground, and is inversely proportional to the duration from when the reaction force F is input to when it is finished. Fig. 10 is a schematic diagram showing (a) a conventional technique when the soil grain size to be excavated is small, (b) a conventional technique when the soil grain size is large, and (c) an embodiment when the soil grain size is large, and Fig. 11 is a graph comparing the reaction force F over time for (a), (b), and (c).

[0029] As shown in Fig. 11, in the conventional technology such as Patent Document 1, when the particle size of the soil to be excavated is small (a), the duration is short but the reaction force F is small, so the impact force rebounding from the soil is small, but when the particle size of the soil is large (b), the reaction force F becomes large, so the impact force rebounding from the soil becomes large. In contrast, according to the present embodiment (c), the duration from the input of the impact force to the end of the input is extended due to the bending of the leaf spring 33, so that the impact force rebounding from the soil can be reduced even if the reaction force F is large. As a result, wear of the excavation claw 20 can be suppressed and the replacement interval can be extended, thereby reducing the effort of the operator to replace the excavation claw 20.

[0030] Meanwhile, as described above, the leaf spring 33 slides both left and right ends 33a against the pressure surface 31a of the spring accommodating chamber 31 each time it is deflected by impact force. Since the leaf spring 33 is made of a material with a lower hardness than the excavation claw 20, wear on the leaf spring 33 side is promoted due to the sliding contact between them, and wear on the excavation claw 20 side, specifically, wear on the pressure surface 31a of the spring accommodating chamber 31 is suppressed. If either of the members 33, 20 is worn, the expected function of the leaf spring 33 is impaired, and it becomes necessary to replace the worn members 33, 20. However, since the leaf spring 33 is inexpensive compared to the excavation claw 20, the cost for restoring the function and therefore the running cost of the tooth 18 can be reduced.

[0031] [Second embodiment] Next, a second embodiment in which the present invention is embodied in another tooth for a bucket of the hydraulic excavator 1 will be described. The main difference from the first embodiment is the leaf spring 45 that biases the excavation claw 20 and the configuration around it, and for example, the engagement relationship between the adapter side and claw side engagement surfaces 22a, 27a and the lock pin 21 is the same as in the first embodiment. Therefore, the common components are given the same part numbers and redundant explanations are omitted, and the differences are described with emphasis. FIG. 12 is an exploded perspective view showing the connection relationship between the adapter 19 and the excavation claw 20 of this embodiment.

[0032] The portion of the adapter 19 in front of the engagement groove 22 is formed by upper and lower stabilizing surfaces 23a, 23b and both left and right side surfaces 41a, 41b, and the pressure-receiving portion 25 at the tip is omitted to form a planar tip surface 42. The upper and lower stabilizing surfaces 23a, 23b have the same shape as those in the first embodiment, but the left and right side surfaces 41a, 41b differ from the first embodiment in that they are planar and gradually approach each other toward the rear, and are hereinafter referred to as tapered surfaces 41a, 41b.

[0033] The cavity 26 of the excavation claw 20 is formed by the upper and lower stabilizing surfaces 29a, 29b and the left and right side surfaces 43a, 43b, and the spring accommodating chamber 31 at the tip is omitted to form a planar tip surface 44. The upper and lower stabilizing surfaces 29a, 29b have the same shape as those in the first embodiment, but the left and right side surfaces 43a, 43b are different from those in the first embodiment in that they are planar and gradually approach each other toward the rear, and are hereinafter referred to as tapered surfaces 43a, 43b. As a result, the tapered surfaces 41a, 41b on the adapter 19 side and the tapered surfaces 43a, 43b on the excavation claw 20 side face each other and are arranged symmetrically on both sides of the axis L.

[0034] Figure 13 is a side cross-sectional view showing the state in which the excavation claw 20 has been completely connected to the adapter 19 by the lock pin 21, and Figure 14 is a cross-sectional view taken along line XIV-XIV in Figure 13 showing the state in which the connection of the excavation claw 20 has been completed. Leaf springs 45 (corresponding to the elastic members of the present invention) are interposed between the left and right tapered surfaces 41a, 41b of the adapter 19 and the left and right tapered surfaces 43a, 43b of the excavation claw 20. In detail, a storage groove 46 extending in the front-rear direction is recessed in each of the left and right tapered surfaces 41a, 41b of the adapter 19. As shown in Fig. 14, a bottom surface 46a of the storage groove 46 forms an angle γ with respect to the axis L, and the left and right tapered surfaces 43a, 43b of the excavation claw 20 form a larger angle δ with respect to the axis L.

[0035] A leaf spring 45 is disposed in each of these storage grooves 46. Each leaf spring 45 is made of a material that is lower in hardness than the digging claws 20 and the adapter 19, in other words, a material that is more easily worn than the digging claws 20 and the adapter 19.

[0036] Each leaf spring 45 is made of an elastic metal plate and has a rectangular plate shape extending forward and backward, and also has a curved arc shape in a plan view that is concave toward the storage groove 46 and convex toward the tapered surfaces 43a, 43b of the excavation claw 20. A rear end 45a (corresponding to one end of the present invention) of each leaf spring 45 protrudes rearward from the storage groove 46, is folded back into a U-shape, and is press-fitted into a press-fit groove 47 formed in the tip surface 42 of the adapter 19.

[0037] As a result, each leaf spring 45 is held in the storage groove 46 with its rear end 45a fixed to the adapter 19, and its front end 45b (corresponding to the other end of the present invention) elastically abuts against the bottom surface 46a of the storage groove 46, while its front-rear central portion 45c elastically abuts against the tapered surfaces 43a, 43b of the excavation claw 20. The biasing force of the leaf spring 45 is converted into a force that displaces the excavation claw 20 rearward due to the inclination of the tapered surfaces 43a, 43b of the excavation claw 20, and this positional displacement is regulated by the adapter 19 via the lock pin 21, so that the excavation claw 20 is maintained in the rearmost position, in other words, in the most protruding position.

[0038] Next, the action of the bucket tooth 18 of this embodiment will be described. FIG. 15 is a cross-sectional view corresponding to FIG. 13, showing a state in which the leaf spring 45 is bent due to an impact force accompanying the excavation of the ground, and FIG. 16 is a cross-sectional view corresponding to FIG. 14, showing a state in which the leaf spring 45 is bent due to the impact force.

[0039] When an impact force caused by digging the ground is input to the digging claw 20, the digging claw 20 starts to displace forward from the state shown in Figures 13 and 14, and the leaf spring 45 starts to bend into the storage groove 46 due to the tapered surfaces 43a, 43b of the digging claw 20. At this time, the leaf spring 45 is compressed in the left-right direction while the center portion 45c is in sliding contact with the tapered surfaces 43a, 43b, and as a result of this left-right compression, the front end portion 45b is in sliding contact with the bottom surface 46a of the storage groove 46. As a result, the impact force is transmitted to the adapter 19 side while bending the leaf springs 45.

[0040] As the excavation claw 20 is displaced forward, the stabilizing surfaces 29a, 29b on the excavation claw 20 side and the stabilizing surfaces 23a, 23b on the adapter 19 side gradually approach each other and come into contact with each other at some point as shown in Figs. 15 and 16. The subsequent impact force is directly transmitted from the excavation claw 20 to the adapter 19 side via the stabilizing surfaces 29a, 29b, 23a, 23b without passing through the leaf spring 45. When the impact force on the excavation claw 20 disappears due to the end of excavation, the excavation claw 20 is displaced backward via the tapered surfaces 43a, 43b due to the elasticity of the leaf spring 45, and returns to the state shown in Figs. 13 and 14. Every time the bucket 8 excavates the ground, the excavation claw 20 is displaced forward and backward through the above process, and the leaf spring 45 is deflected accordingly to transmit the impact force to the adapter 19 side.

[0041] As a result, as in the first embodiment, the duration from input of the impact force to its end is lengthened by the elastic deformation of each leaf spring 45, thereby reducing the impact force rebounding from the soil and sand. This makes it possible to suppress wear on the excavation claws and extend the replacement interval, thereby reducing the labor required by the worker to replace the excavation claws.

[0042] Particularly in this embodiment, the tapered surfaces 43a, 43b on the excavation claw 20 side are set at a larger angle δ (>γ) with respect to the angle γ of the bottom surface 46a of the storage groove 46 based on the axis L. As the position of the excavation claw 20 moves forward, frictional resistance is generated at the contact points between the leaf springs 45 and the tapered surfaces 43a, 43b, but since this frictional resistance is increased compared to when the angle δ<γ, the impact force can be further reduced.

[0043] Meanwhile, as described above, each time each leaf spring 45 is deflected by receiving an impact force, the central portion 45c slides against the tapered surfaces 43a, 43b of the digging claws 20, and the front end portion 45b slides against the bottom surface 46a of the storage groove 46 of the adapter 19. Since each leaf spring 45 is made of a material that is lower in hardness than the digging claws 20 and the adapter 19, wear on the digging claws 20 and the adapter 19 can be suppressed, and the running costs of the teeth 18 can be reduced, although this will not be described again.

[0044] Although the description of the embodiment is finished above, the aspects of the present invention are not limited to this embodiment. For example, in the above embodiment, the tooth 18 for the bucket of the hydraulic excavator 1 is embodied, but the present invention is not limited to this as long as it is a construction machine that performs excavation work using a bucket equipped with teeth, and may be applied to, for example, a wheel loader, a crane, a dump truck, etc. In addition, in the above embodiment, leaf springs 33, 45 are provided as elastic members, but this is not limited to this, and the shape, type, etc. can be changed arbitrarily as long as it has the function of elastically biasing the digging claw 20.

[0045] In the above embodiment, the connecting portion is constituted by the adapter side engagement surface 22a, the claw side engagement surface 27a, and the lock pin 21, but the present invention is not limited to this. For example, a through hole penetrating in the up-down or left-right direction may be formed in the adapter 19, and a long hole extending in the front-rear direction may be formed on both the top and bottom side surfaces or both the left and right side surfaces of the excavation claw 20 fitted onto the adapter 19, and the lock pin may be press-fitted into the through hole of the adapter 19 via the long hole. Even in this case, the lock pin can prevent the excavation claw 20 from falling off the adapter 19, and the positional displacement of the excavation claw 20 in the front-rear direction within the range of the long hole can be permitted, so that the same function as the connecting portion of the above embodiment can be obtained. [Explanation of symbols]

[0046] 1. Hydraulic excavator (construction machinery) 8. Bucket 8a Tip edge 18 Tooth 19 Adapters 20 Digging Claw 21 Lock pin (connection part) 22a Adapter side engagement surface (connection portion) 25a Pressure surface 26 Cavity 27a Claw side engagement surface (connection part) 31a Pressure surface 33,45 Leaf spring (elastic member) 33a Both ends 33b,45c central part 41a, 41b, 43a, 43b Tapered surfaces 45a Rear end (one end) 45b Front end (other end) 46 Storage Groove 46a Bottom

Claims

1. A plurality of adapters provided on a leading edge of the bucket and protruding toward the leading edge; a digging claw having a cavity formed at a base end thereof, the cavity being open toward the adapter, the digging claw being detachably attached by fitting the cavity onto the adapter; A tooth for a bucket of a construction machine comprising: a connecting portion that prevents the excavation claw from falling off the adapter and allows the excavation claw to be displaced toward the tip end and the base end; an elastic member interposed between the adapter and the excavation claw and elastically biasing the excavation claw toward the tip side; A tooth for a bucket of a construction machine, comprising:

2. The elastic member is a leaf spring that is disposed within the cavity, has a curved plate shape that is concave on the tip side of the digging claw and convex on the base end side of the digging claw, and has both ends abutted against pressure surfaces formed within the cavity and a center abutted against a pressure-receiving surface formed on the adapter, urging the digging claw toward the tip side.

2. The tooth for a bucket of a construction machine according to claim 1.

3. A pair of tapered surfaces are formed on both sides of the adapter, the tapered surfaces gradually approaching each other toward the tip side, and a storage groove is recessed into each of the tapered surfaces, A pair of tapered surfaces are formed on both sides of the cavity of the excavation claw, the tapered surfaces gradually approaching each other toward the tip side, and the tapered surfaces face the tapered surfaces of the adapter, The elastic members are arranged in the storage grooves, and are plate-shaped curved so as to be concave toward the storage groove side of the adapter and convex toward the tapered surface side of the cavity. One end of each of the elastic members is fixed to the adapter, and the other end of each of the elastic members is in contact with the bottom surface of the storage groove. The center of each of the elastic members is in contact with the tapered surface of the excavation claw, and the elastic members are leaf springs that urge the excavation claw toward the tip side.

2. The tooth for a bucket of a construction machine according to claim 1.

4. The leaf spring is made of a material having a lower hardness than the digging claw.

3. The tooth for a bucket of a construction machine according to claim 2.

5. The leaf spring is made of a material having a lower hardness than the digging claw and the adapter.

4. The tooth for a bucket of a construction machine according to claim 3.

6. The connecting portion comprises an adapter-side engagement surface formed at the base end of the adapter and facing the base end side, a claw-side engagement surface formed at the base end of the excavation claw and facing each other at a predetermined interval on the base end side of the adapter-side engagement surface, and a lock pin disposed with play between the adapter-side engagement surface and the claw-side engagement surface.

2. The tooth for a bucket of a construction machine according to claim 1, further comprising:

Images