A vibration-reducing jackhammer with a handle having two degrees of freedom

Abstract

The invention discloses a handle vibration-reducing jackhammer with two degrees of freedom, comprising a first vibration-reducing mechanism and a second vibration-reducing mechanism. The first vibration-reducing mechanism and the second vibration-reducing mechanism respectively comprise a shell, in which an X-structure arm is installed, and the X-structure arm comprises two L-shaped long rods, two first connecting rods, two cross-hinged second connecting rods, two cross-hinged third connecting rods, and a fourth connecting rod. One end of the two L-shaped long rods is connected to a first connecting seat or a second connecting seat after being hinged, and a first connecting rod is hinged on each of the two L-shaped long rods, the other end of the first connecting rod is hinged to one end of two cross-hinged second connecting rods, the other end of the two cross-hinged second connecting rods is hinged to one end of two cross-hinged third connecting rods, and the other end of the two cross-arranged third connecting rods is hinged to a fourth connecting rod respectively; the other ends of the two fourth connecting rods are hinged; in two different vibration-reducing mechanisms, the two L-shaped long rods located on the same side are connected through a handle.

Description

Technical Field

[0001] The invention belongs to the field of jackhammers, and in particular relates to a jackhammer with a two-degree-of-freedom handle and vibration reduction. Background Art

[0002] Currently, construction workers operating heavy jackhammers or road breakers are subject to excessive vibration in their hands and arms when using them, which eventually leads to severe vibration-related syndrome. The most harmful vibrations are in the frequency range between 4Hz and 50Hz. Traditional springs or dampers cannot solve this vibration problem because workers need to press down to hold the machine tightly to obtain high demolition efficiency, and the compression of traditional springs or materials leads to a sharp increase in stiffness, which seriously reduces the vibration isolation performance. Therefore, products with different active vibration control have appeared on the market, but the manufacturing and maintenance costs are extremely high, and the actual reduction in vibration levels is still quite limited. Summary of the invention

[0003] In view of the shortcomings of the prior art, an object of the present invention is to provide a handle-vibration-reducing jackhammer with two degrees of freedom, which fully utilizes nonlinear characteristics to achieve better passive vibration control performance.

[0004] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0005] In a first aspect, an embodiment of the present invention provides a handle-vibration-damping jackhammer with two degrees of freedom, comprising a first vibration-damping mechanism and a second vibration-damping mechanism symmetrically arranged relative to the axis of the jackhammer; the first vibration-damping mechanism and the second vibration-damping mechanism have the same structure, each comprising a shell, in which an X-structure arm is installed, the X-structure arm comprising two L-shaped long rods, two first connecting rods, two cross-hinged second connecting rods, two cross-hinged third connecting rods, and a fourth connecting rod; one end of the two L-shaped long rods is connected to the first connecting seat or the second connecting seat after being hinged, and a first connecting rod is hinged on each of the two L-shaped long rods, the two first connecting rods are located on different sides of the two L-shaped long rods, the other end of the first connecting rod is hinged to one end of the two cross-hinged second connecting rods, the other end of the two cross-hinged second connecting rods is hinged to one end of the two cross-hinged third connecting rods, and the other end of the two cross-arranged third connecting rods is hinged to a fourth connecting rod respectively; the other ends of the two fourth connecting rods are hinged; in two different vibration-damping mechanisms, the two L-shaped long rods located on the same side are connected by a handle.

[0006] As a further technical solution, it also includes a top mounting seat installed on the top of the jackhammer upper cover, and a first bottom mounting seat and a second bottom mounting seat fixed on the jackhammer lower cover; the top mounting seat and the first bottom mounting seat are connected via a first connecting seat, and the top mounting seat and the second bottom mounting seat are connected via a second connecting seat; a first vibration reduction mechanism is installed on the first connecting seat and the first bottom mounting seat, and a second vibration reduction mechanism is installed on the second connecting seat and the second bottom mounting seat.

[0007] As a further technical solution, the first vibration reduction mechanism and the second vibration reduction mechanism each include an inner cover, and the inner cover is fixed on the first connecting seat and the first bottom mounting seat, or on the second connecting seat and the second bottom mounting seat.

[0008] As a further technical solution, it also includes a support rod mounting seat, which is installed on the first connecting seat or the second connecting seat and is connected to the hinge points of the two L-shaped long rods.

[0009] As a further technical solution, it also includes a bushing, which is installed on the first connecting seat or the second connecting seat and is connected to the hinged ends of the two fourth connecting rods.

[0010] As a further technical solution, a connecting rod guide rail is also included, which can limit the lateral movement of the X-structure arm in the vertical plane direction, and the hinge points of the two cross-hinged second connecting rods are connected to the connecting rod guide rail.

[0011] As a further technical solution, a vertically adjustable stiffness system is also included.

[0012] As a further technical solution, the adjustable stiffness system includes a vertically arranged bolt, which passes through the support rod mounting seat and is connected to the top of the connecting rod guide rail, and a nut is threaded on the bolt. A lower stopper is installed on the connecting rod guide rail, and the lower stopper is connected to the nut via two springs arranged in parallel.

[0013] As a further technical solution, the hinge points of the second link and the third link are connected via a horizontally arranged first spring; the hinge points of the third link and the fourth link are connected via a horizontally arranged second spring; and the hinge points of the fourth link and the fifth link are connected via a horizontally arranged third spring.

[0014] As a further technical solution, the hinge points of the two L-shaped long rods and the hinge points of the second connecting rod and the third connecting rod are connected via an inclined fourth spring.

[0015] The beneficial effects of the above embodiments of the present invention are as follows:

[0016] The X-shaped first vibration reduction mechanism and the second vibration reduction mechanism proposed by the present invention are well combined with the jackhammer, achieving good vibration isolation performance while having a compact structure. The parameters of the X-shaped first vibration reduction mechanism and the second vibration reduction mechanism are flexibly adjustable, and the disassembly and assembly are very convenient. While obtaining a high-efficiency vibration isolation effect, the structural stability is also guaranteed, which can fully meet the complex and high-intensity work of the jackhammer. Due to the high static and low dynamic stiffness characteristics of the X-shaped first vibration reduction mechanism and the second vibration reduction mechanism, when the handle is pressed down, the load-bearing capacity increases rapidly and quickly reaches the working quasi-zero stiffness area. The added vertical adjustable stiffness system can compensate for the stiffness of the system in the negative stiffness area, and can also meet the needs of different operators, while expanding the quasi-zero stiffness area.

[0017] The present invention successfully solves the vibration isolation problem when operating various construction tools in the construction field. Compared with the jackhammers with active and passive vibration reduction functions currently on the market, the jackhammers equipped with the X-shaped first and second vibration reduction mechanism handles can greatly improve the vibration reduction performance, but the cost is still low and can be widely introduced to the market. More importantly, combined with the structural design experience of this study, the X-shaped first and second vibration reduction mechanisms can be applied to different handheld vibration tools and machines in the future. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0019] Figure 1 It is a structural schematic diagram of the existing jackhammer body of the present invention;

[0020] Figure 2 , Figure 3 It is a schematic diagram of the top, bottom and middle parts of the existing jackhammer body after the mounting base is connected;

[0021] Figure 4 Schematic diagram of the structure after the inner cover of the X-structure arm is installed;

[0022] Figure 5 It is a structural diagram of the X-structure arm;

[0023] Figure 6 It is a schematic diagram of the structure in which the X-structure arm is installed on the inner cover;

[0024] Figure 7 , Figure 8 Schematic diagram of the structure of the vertical adjustable system installed on the inner cover;

[0025] Figure 9 (a) and Figure 9 (b) are schematic diagrams of the overall structure of the present invention;

[0026] Fig.10A schematic diagram of the overall structure of the present invention when not mounted on a jackhammer body;

[0027] Figure 11(a) and Figure 11(b) are X-structure arm models at the initial position;

[0028] Fig.12 Schematic diagram of the relationship between the vertical static force F and the displacement y of the X-structure arm handle;

[0029] Fig.13 Schematic diagram of the relationship between the vertical static force F and displacement y of the X-structure arm handle with different rod lengths L4;

[0030] Fig.14 Schematic diagram of the relationship between the vertical static force F and displacement y of the X-structure arm handle with different rod lengths L3;

[0031] Fig.15 Schematic diagram of pressure measurement under the handle;

[0032] Fig.16 Schematic diagram of the Δy displacement measurement in the vertical direction of the handle;

[0033] Fig.17 It is a schematic diagram of the relationship between the tangential force F, the vertical component force F0 and the vertical displacement of the handle of the X-structure arm with 4 horizontal K1=31.8N / mm springs;

[0034] Fig.18 It is a schematic diagram of the relationship between the force F and the displacement Δy of the handle;

[0035] Fig. 19(a) and Fig. 19(b) are schematic diagrams of the first and second measurements of the experimental simulation force F and displacement Δy (a) of the X-structure arm handle with 8 horizontal K1 = 31.8 N / mm springs and diagonal K2 = 0.23 N / mm springs, respectively;

[0036] Fig. 20 It is a schematic diagram of the maximum load-bearing capacity position of the X-structure arm;

[0037] In the figure: 1 jackhammer body, 2 top mounting seat, 3 connecting seat, 4 bottom mounting seat; 5 inner cover, 6X structural arm; 6-1 L-shaped long rod, 6-2 first connecting rod, 6-3 second connecting rod, 6-4 third connecting rod, 6-5 fourth connecting rod;

[0038] 7 support rod mounting seat, 8 bushing, 9 connecting rod guide rail, 10 bolt, 11 nut, 12 lower stopper, 13 middle connecting nut, 14 spring; 15 handle, 16 outer cover, 17 first spring, 18 second spring, 19 third spring, 20 fourth spring. DETAILED DESCRIPTION

[0039] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0040] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless otherwise explicitly stated in the present invention, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "include" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof;

[0041] In a typical embodiment of the present invention, Figure 1-Figure 1 1, it comprises a top mounting seat mounted on the top of the upper cover of the jackhammer, and a first bottom mounting seat and a second bottom mounting seat fixed on the lower cover of the jackhammer; the top mounting seat is connected to the first bottom mounting seat through a first connecting seat, and the top mounting seat is connected to the second bottom mounting seat through a second connecting seat; a first vibration reduction mechanism is mounted on the first connecting seat and the first bottom mounting seat, and a second vibration reduction mechanism is mounted on the second connecting seat and the second bottom mounting seat; the first vibration reduction mechanism and the second vibration reduction mechanism are symmetrically arranged relative to the axis of the jackhammer; the first vibration reduction mechanism and the second vibration reduction mechanism have the same structure, each comprising a shell, an X-structure arm is mounted in the shell, and the X-structure arm comprises two L-shaped long rods , two first connecting rods, two cross-hinged second connecting rods, two cross-hinged third connecting rods, and a fourth connecting rod; one end of the two L-shaped long rods is hinged and connected to the first connecting seat or the second connecting seat, and a first connecting rod is hinged on each of the two L-shaped long rods, the two first connecting rods are located on different sides of the two L-shaped long rods, the other end of the first connecting rod is hinged to one end of the two cross-hinged second connecting rods, the other end of the two cross-hinged second connecting rods is hinged to one end of the two cross-hinged third connecting rods, and the other end of the two cross-arranged third connecting rods is hinged to a fourth connecting rod respectively; the other ends of the two fourth connecting rods are hinged; in two different vibration damping mechanisms, the two L-shaped long rods located on the same side are connected by a handle.

[0042] Furthermore, the first vibration damping mechanism and the second vibration damping mechanism each include an inner cover and an outer cover, wherein the inner cover is fixed on the first connecting seat and the first bottom mounting seat, or on the second connecting seat and the second bottom mounting seat, and the outer cover cooperates with the inner cover to enclose the first vibration damping mechanism or the second vibration damping mechanism in the cover body.

[0043] Furthermore, it also includes a support rod mounting seat, which is installed on the first connecting seat or the second connecting seat and is connected to the hinge points of the two L-shaped long rods.

[0044] Furthermore, it also includes a bushing, which is installed on the first connecting seat or the second connecting seat and is connected to the hinged ends of the two fourth connecting rods.

[0045] Furthermore, it also includes a connecting rod guide rail 9, which can limit the lateral movement of the X-structure arm in the vertical plane direction, and the hinge points of the two cross-hinged second connecting rods are connected to the connecting rod guide rail.

[0046] Further, such as Figure 6 , Figure 7 As shown, it also includes a vertically adjustable stiffness system, which includes a vertically arranged bolt 10, which passes through the support rod mounting seat 7 and is connected to the top of the connecting rod guide rail 9, and a nut 11 is threaded on the bolt, and a lower stopper 12 is installed on the connecting rod guide rail, and the lower stopper 12 is connected to the nut through two springs 14 arranged in parallel.

[0047] Further, such as Figure 8 As shown, the hinge points of the second connecting rod and the third connecting rod are connected via a horizontally arranged first spring 17; the hinge points of the third connecting rod and the fourth connecting rod are connected via a horizontally arranged second spring 18; the hinge points of the fourth connecting rod and the fifth connecting rod are connected via a horizontally arranged third spring 19; the hinge points of the two L-shaped long rods and the hinge points of the second connecting rod and the third connecting rod are connected via an obliquely arranged fourth spring 20; in this embodiment, the first, second and third springs have the same function, which is to increase the restoring force of the structure, but with only these horizontal springs, the structure will have a negative stiffness problem, so adding a diagonal spring, i.e. the fourth spring 20 mentioned above, can effectively remove the negative stiffness and increase the effective quasi-zero stiffness working range through reasonable parameter setting, and can also further increase the restoring force.

[0048] 1. The overall installation process and each component of the above device are described below:

[0049] 1. New top, bottom and middle connection installation seat

[0050] like Figure 1 As shown, the original handle of the jackhammer is removed, and the structure of the jackhammer body 1 after the removal is as follows Figure 1 As shown, a top mounting base 2 is then installed on the top cover of the jackhammer body 1, with 4 M6 bolts for fixing the handle; the length of the new M6 bolts is 10mm longer than the old M6 screws;

[0051] In order to stabilize the X-structure arm, two bottom mounting bases 4 are designed and fixed on both sides of the lower part of the jackhammer body 1 for mounting and fixing the X-structure and the cover. Figure 2 , Figure 3As shown, no new holes need to be made. The two bottom mounts 4 are connected with 4 new M8 bolts which are 10mm longer than the old screws.

[0052] like Figure 2 , Figure 3 As shown, two connecting mounts 3 are used to connect the top mount 2 and the two bottom mounts 4; more importantly, the two connecting mounts 3 will be used to assemble the new cover and the X-structure arm; two M6X16 bolts are used to bolt the connecting mount 3 to the upper part of the top mount 2. Two M6X12 bolts are used to bolt the bottom mount 4 to the connecting mount 3.

[0053] 2X structural arm inner cover

[0054] like Figure 4 As shown, after assembling the upper mount, connecting the mount and the bottom mount, the inner cover 5 of the X-structure arm is bolted to the bottom, and the mount is connected with 6 M6X12 Hexagon Countersunk head bolts. The inner cover 5 can protect the X-structure arm from external brackets and stones. In addition, the inner cover 5 and the outer cover can cover the X-structure arm and have a guiding role.

[0055] 3X vibration reduction structural arm

[0056] The X-structure arm 6 consists of 10 rods. Figure 5 As shown. The two L-shaped long rods 6-1 at the top are lever-type handle connecting rods, which connect the two handles with the handles on the other side through the connecting rods, and are also connected to the downward connecting X-shaped vibration reduction mechanism with two vertical rods. In order to reduce friction and clearance, pressure ball bearings are applied between each rod at the joint. In order to couple and extend the length of the spring, four spring coupling plates are introduced in the second and third layers; specifically, they include two L-shaped long rods 6-1, two first connecting rods 6-2, two cross-hinged second connecting rods 6-3, two cross-hinged third connecting rods 6-4, and a fourth connecting rod 6-5; one end of the two L-shaped long rods 6-1 is hinged, and a first connecting rod 6-2 is hinged on each of the two L-shaped long rods 6-1, the other end of the first connecting rod 6-2 is hinged to one end of two cross-hinged second connecting rods 6-3, the other end of the two cross-hinged second connecting rods 6-3 is hinged to one end of two cross-hinged third connecting rods 6-4, and the other end of the two cross-arranged third connecting rods 6-4 is hinged to a fourth connecting rod 6-5 respectively; the other ends of the two fourth connecting rods 6-5 are hinged and connected to the bushing 8 below, and the bushing 8 is fixed on the above-mentioned connecting mounting seat.

[0057] Furthermore, the above-mentioned cross-hinging means: cross-arranged and hinged together.

[0058] Assembly of 4X vibration-damping structural arms

[0059] like Figure 6 As shown, two new parts are designed, namely the support rod mount 7 and the 9mm bushing 8, which are used to assemble the X-structure arm into the connecting mount and the bottom mount; as an isolation from the pressure ball bearing, the M8 spring washer and the M8 nut can be tightened to reduce the gap between the X-structure arm and the bracket.

[0060] The lower joint of the X-structure arm is assembled on the bottom mounting seat by M8X50 hexagon socket countersunk bolts; Figure 6 The 9mm bushing shown is designed to maintain the same vertical plane as the top joint of the X-structure arm. With the pressure ball bearing located between the washer and the X-structure arm, the M8X50 hexagon socket countersunk head bolt and spring washer can tighten the X-structure arm to the bottom mount.

[0061] 5-link guide

[0062] In order to keep the X-structure arm moving in the vertical direction, a Figure 7 The connecting rod guide rail shown in the figure can also limit the lateral movement of the X-structure arm in the vertical plane direction. The connecting rod guide rail 9 is fixed to the above-mentioned connecting mounting seat by two medium-sized connecting bolts. A connecting rod guide rail groove is also provided on the connecting rod guide rail 9, and the lower stopper 12 below is installed in the groove.

[0063] 6 Assembly of the upper handle

[0064] The two upper handles 15 are respectively connected to the L-shaped long rod 6-1 of the X-structure arm through four M5X12 hexagonal countersunk bolts.

[0065] 7Vertical adjustable stiffness system

[0066] In order to improve the system stiffness when the X-structure arm reaches the negative stiffness zone, an adjustable stiffness system is designed, such as Figure 7 , Figure 8 As shown; when the handle is pressed down, the middle connecting nut 13 (the nut corresponds to the nut at the intersection of the two cross-set second connecting rods 6-3) will contact and plug with the lower stopper 12 at the set position, and the vertical adjustable stiffness system will work to increase the vertical stiffness. The contact position should be adjusted according to the specific actual measured stiffness curve to remove the negative stiffness; the M5X60 hexagonal countersunk bolt 10 can adjust the height of the upper connecting nut 11 of the spring 14, thereby changing the initial vertical force.

[0067] 8. Assembly of X-structure arm outer cover

[0068] The outer cover 16 is assembled on the inner cover with 6 M4X16 hexagon countersunk bolts.

[0069] 2. Below is the static analysis of XSAVA in Admas;

[0070] As shown in FIG11(a), the new X-structure arm proposed in this embodiment consists of a 2.5-layer X-structure and two long handles. The two long handles connect the jackhammer to the rotary joint. At the bottom layer of the new X-structure arm, two L1 rods connect the jackhammer to the rotary joint. At the top layer of the X-structure arm, two L3 rods connect the handle to the rotary joint. As shown in FIG11(b), in the X-structure arm and jackhammer system, there are two horizontal springs with K1 stiffness and two ramp springs with K2 stiffness.

[0071] Fig.12 The relationship between the static force F and displacement of the X-structure arm handle in the vertical direction is shown when L1 = 50mm, L2 = 80mm, L3 = 70mm, L4 = 60mm, Lh = 100mm, K1 = 100N / mm, K2 = 0N / mm and α = 45°. In the early stage of the curve, the slope (dF / dy) is very high, which means that its static stiffness is very high. When the handle is pushed down to about 78mm, the slope (dF / dy) drops rapidly to below 1. When the handle is pushed down into zone B, the slope (dF / dy) is close to zero, which means that it enters the quzai-zero stiffness zone. As mentioned earlier, the resonant frequency of the X-shaped structure is mainly affected by linear factors, so The X-structure arm of the jackhammer can maintain perfect vibration isolation performance in the B area.

[0072] For a constant mass vibration system, it cannot work in the negative stiffness region. However, when the jackhammer is working, the force pushing down the handle is variable, and it can still work in the negative stiffness region.

[0073] The influence of rod length L4 is analyzed as follows:

[0074] Fig.13 It shows the effect of rod length L4 on the overall static force when L1 = 50mm, L2 = 80mm, L3 = 70mm, Lh = 100mm, K1 = 100N / mm, K2 = 0N / mm and α = 45°. In the early stage of pushing down, the slope of the curve (static stiffness dF / dy) is lagging. As the rod length L4 increases, the initial θ1 will decrease and the high static force F will increase at zero stiffness. Therefore, the rod length L4 should be increased to obtain a greater load capacity.

[0075] Effect of rod length L3

[0076] Fig.14The effect of the rod length L3 on the static force is shown when L1 = 50mm, L2 = 80mm, L4 = 60mm, Lh = 100mm, K1 = 100N / mm, K2 = 0N / mm and α = 45°. As the rod length L3 increases, the initial θ1 will decrease and the handle force capacity will decrease. Therefore, in order to improve the handle force capacity, the rod length L3 should be appropriately reduced.

[0077] Summary of static analysis:

[0078] When the X-structure arm only connects the horizontal springs of the second and third layers, the quasi-zero stiffness zone is small and limited. Therefore, applying an adjustable vertical stiffness system can help adjust the pressure for different operators.

[0079] 3. Manufacturing and Assembly

[0080] To assemble the new X-structure arm, disassemble the original handle with the cable. The new upper mount will replace it with the same bolts. Then assemble all the parts of the X-structure arm and the cover in the previous assembly order, and the spring will be assembled at the end. After adjusting the vertical adjustable stiffness system, the outer cover will be closed.

[0081] 1. Static stiffness measurement

[0082] Table 1. Parameter definitions

[0083]

[0084]

[0085] 2. Measurement processing

[0086] The measured values ​​of the downward force F and displacement Δy are as follows Fig.15 , Fig.16 As shown, with the help of two medium-sized support rods moving up and down, the rope lifting the weight can be perpendicular to the handle. Therefore, the tangential force F can be obtained by measuring the weight of the weight. Then, the vertical force F0 can be obtained from F*cosθ. The corresponding vertical displacement of the top handle is obtained by measuring the drop height of the handle;

[0087] 3. Experimental static stiffness analysis

[0088] Table 2. Measured data of F and Δy and corresponding F0 with 4 levels of K1 = 31.8 N / mm spring

[0089]

[0090] Fig.17The force and displacement of an X-structure arm with 4 horizontal springs in the tangential and vertical directions are shown. The initial vertical downforce is about 57N because of the initial force and preload of the horizontal springs. When the handle moves down to the zero stiffness position 95mm, it reaches the maximum force capacity of about 180N. When the handle is operated near this point, the vibration isolation performance is better.

[0091] In order to obtain greater downforce capacity and a longer quasi-zero stiffness area, a static analysis simulation was performed in Adams, such as Fig.18 As shown in Figure 23, the three-layer X-structure arm in the Adams model has horizontal springs and diagonal springs. In order to obtain greater downforce capacity and a longer quasi-zero stiffness area, a static analysis simulation was performed in Adams.

[0092] According to the simulation results of Figure 19(a) and Figure 19(b), the system connects 8 horizontal k1=31.8N / mm springs and 4 diagonal K2=0.23N / mm springs between layers 1, 2, and 3 on both sides of the X-structure arm to obtain appropriate downforce capacity and a longer quasi-zero stiffness area.

[0093] Fig. 20 The experimental and simulation results of the tangential force F and displacement Δy in the vertical direction of the handle of the X-structure arm with 8 horizontal springs and 4 diagonal springs are shown. The initial force and the maximum force increase to 80N and 288N respectively. When the two handles are pushed down to about 95mm as shown in the figure, it reaches the maximum force point. After that, the thrust begins to decrease. The quasi-zero stiffness area is from 70mm to 120mm. The X-structure arm will have extremely strong vibration isolation performance when working under quasi-zero stiffness.

[0094] Table 3. Measured data of F and Δy for 8 horizontal springs with K1=31.8N / mm and 4 diagonal springs with K2=0.23N / mm;

[0095]

[0096]

[0097] In this embodiment, the X-shaped anti-vibration structure is a good combination of nonlinear control theory and feasible structural design. The X-shaped anti-vibration structure is well combined with the jackhammer to achieve good vibration isolation performance while being compact. The parameters of the X-shaped anti-vibration structure are flexibly adjustable, and it is very convenient to disassemble and assemble. While achieving efficient vibration isolation effects, the structural stability is also guaranteed, which can fully meet the complex and high-intensity work of the jackhammer. Due to the high static and low dynamic stiffness characteristics of the X-shaped anti-vibration structure, when the handle is pressed down, the load-bearing capacity increases rapidly and quickly reaches the quasi-zero stiffness area of ​​the work. The added vertical adjustable stiffness system can compensate for the stiffness of the system in the negative stiffness area, and can also meet the needs of different operators while expanding the quasi-zero stiffness area.

[0098] This innovative technology successfully solves the vibration isolation problem when operating various construction tools in the construction field. Compared with the jackhammers with active and passive vibration reduction functions currently on the market, the jackhammer equipped with an X-shaped anti-vibration handle can greatly improve the vibration reduction performance, but the cost is still low and can be widely introduced to the market. More importantly, combined with the structural design experience of this study, the X-shaped anti-vibration structure can be applied to different handheld vibration tools and machines in the future.

[0099] Finally, it should be noted that relational terms such as first and second are merely used to distinguish one entity or operation from another entity or operation, but do not necessarily require or imply any actual relationship or order between these entities or operations.

[0100] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A vibration-reducing jackhammer with a handle having two degrees of freedom, characterized in that: The invention comprises a first vibration reduction mechanism and a second vibration reduction mechanism, a support rod mounting seat, a connecting rod guide rail, and an adjustable stiffness system, which are symmetrically arranged relative to the axis of the jackhammer; the first vibration reduction mechanism and the second vibration reduction mechanism have the same structure, and each comprises a shell, in which an X-structure arm is installed, and the X-structure arm comprises two L-shaped long rods, two first connecting rods, two cross-hinged second connecting rods, two cross-hinged third connecting rods, and a fourth connecting rod; one end of the two L-shaped long rods is connected to the first connecting seat or the second connecting seat after being hinged, and a first connecting rod is hinged on each of the two L-shaped long rods, and the two first connecting rods are located on different sides of the two L-shaped long rods, the other end of the first connecting rod is hinged to one end of the two cross-hinged second connecting rods, the other end of the two cross-hinged second connecting rods is hinged to one end of the two cross-hinged third connecting rods, and the other end of the two cross-articulated third connecting rods is hinged to a fourth connecting rod respectively; the other ends of the two fourth connecting rods are hinged; in two different vibration reduction mechanisms, the two L-shaped long rods located on the same side are connected by a handle; The support rod mounting seat is mounted on the first connecting seat or the second connecting seat and is connected to the hinge points of the two L-shaped long rods; The connecting rod guide rail limits the lateral movement of the X-structure arm in the vertical plane direction, and the hinge points of the two cross-hinged second connecting rods are connected to the connecting rod guide rail; The adjustable stiffness system includes a vertically arranged bolt, which passes through a support rod mounting seat and is connected to the top of a connecting rod guide rail, and a nut is threadedly connected to the bolt. A lower stopper is installed on the connecting rod guide rail, and the lower stopper is connected to the nut via two springs arranged in parallel.

2. A vibration-damping jackhammer with a handle having two degrees of freedom as claimed in claim 1, characterized in that: Also included is a top mounting seat mounted on the top of the upper cover of the jackhammer, and a first bottom mounting seat and a second bottom mounting seat fixed to the lower cover of the jackhammer; The top mounting seat is connected to the first bottom mounting seat through a first connecting seat, and the top mounting seat is fixedly connected to the second bottom mounting seat through a second connecting seat; a first vibration reduction mechanism is installed on the first connecting seat and the first bottom mounting seat, and a second vibration reduction mechanism is installed on the second connecting seat and the second bottom mounting seat.

3. A vibration-damping jackhammer with a handle having two degrees of freedom as claimed in claim 2, characterized in that: The shell comprises an inner cover and an outer cover, wherein the inner cover is fixed on the first connecting seat and the first bottom mounting seat, or on the second connecting seat and the second bottom mounting seat, and the outer cover is connected to the inner cover.

4. A jackhammer with a handle having two degrees of freedom as claimed in claim 2, characterized in that: It also includes a bushing, which is installed on the first connecting seat or the second connecting seat and is connected to the hinged ends of the two fourth connecting rods.

5. A jackhammer with a handle having two degrees of freedom as claimed in claim 1, characterized in that: The adjustable stiffness system is a vertically adjustable stiffness system.

6. A jackhammer with a handle having two degrees of freedom as claimed in claim 1, characterized in that: The hinge points of the first link and the second link are connected via a horizontally arranged first spring; the hinge points of the second link and the third link are connected via a horizontally arranged second spring; and the hinge points of the third link and the fourth link are connected via a horizontally arranged third spring.

7. A jackhammer with a handle having two degrees of freedom as claimed in claim 1, characterized in that: The hinge points of the two L-shaped long rods are connected to the hinge points of the first connecting rod and the second connecting rod through an inclined fourth spring.

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