CN114198063B

CN114198063B - Fracturing device suitable for coal bed gas exploitation

Info

Publication number: CN114198063B
Application number: CN202111537743.9A
Authority: CN
Inventors: 于天援; 杜志刚; 李爱霞; 何宏俊; 胡金建; 孙涛
Original assignee: Dezhou Horizon Petroleum Technology Co ltd
Current assignee: Dezhou Horizon Petroleum Technology Co ltd
Priority date: 2021-12-15
Filing date: 2021-12-15
Publication date: 2022-11-15
Anticipated expiration: 2041-12-15
Also published as: CN114198063A

Abstract

The invention provides a fracturing device suitable for coal bed gas exploitation, and relates to the technical field of coal bed gas exploitation tools. The invention comprises a fixed sleeve with a liquid discharge hole, a sliding sleeve with a liquid passing hole and a control mechanism for controlling the communication between the liquid discharge hole and the liquid passing hole, wherein the sliding sleeve is sleeved in the fixed sleeve in a sliding manner, and the liquid discharge hole and the liquid passing hole are provided with sealing plugs. The invention has simple structure and reasonable design, and solves the technical problems that cement outside the fracturing device can influence the opening and closing of the fracturing device after well cementation and is difficult to open in the prior art; and in the later fracturing process, the repeated opening and closing of the fracturing device are ensured.

Description

Fracturing device suitable for coal bed gas exploitation

Technical Field

The invention relates to the technical field of coal bed gas exploitation tools, in particular to a fracturing device suitable for coal bed gas exploitation.

Background

The coal bed gas is a gas resource associated with coal and symbiotic with the coal, refers to hydrocarbon gas stored in a coal bed, takes methane as a main component, and belongs to unconventional natural gas. The coal bed gas mainly adsorbs the surfaces of coal matrix particles, partially dissociates in coal pores or dissolves in coal bed water, is an associated mineral resource of coal, and is a clean and high-quality energy and chemical raw material which is grown internationally in recent years. The mining mode of the coal bed gas comprises surface drilling mining and underground gas drainage, and the former is a common coal bed gas mining mode.

When the coal bed gas is exploited by drilling on the ground, the coal bed gas is difficult to develop due to extremely low porosity and permeability of coal rocks, and the high-efficiency development of the coal bed gas can be realized only by hydraulic fracturing modification, so that the fracturing technology is an important yield increasing technology for improving the yield of the coal bed gas well. However, the existing fracturing device cannot be used for external coal bed gas well cementation, and after well cementation, cement on the outer side of the fracturing device can affect the opening and closing of the fracturing device, so that the fracturing device has a construction risk which is difficult to open. In view of this, after intensive research, the inventors propose a fracturing device suitable for coal bed gas exploitation.

Disclosure of Invention

The invention aims to provide a fracturing device suitable for coal bed gas exploitation, which can realize the first cementing construction outside the fracturing device and avoid the phenomenon that cement blocks a liquid discharge hole; and in the later fracturing process, the repeated opening and closing of the fracturing device are ensured.

The embodiment of the invention is realized by the following steps:

the embodiment provides a fracturing device suitable for coal bed gas exploitation, and it is including the fixed sleeve that has the outage, the slip sleeve that has the liquid passing hole and be used for controlling above-mentioned outage and the control mechanism that the liquid passing hole is linked together, and above-mentioned slip sleeve slip cap is located in above-mentioned fixed sleeve, and above-mentioned outage and above-mentioned liquid passing hole are equipped with the shutoff and block up.

In some embodiments of the present invention, the inner side wall of the fixed sleeve is provided with a guide groove, and the outer side wall of the sliding sleeve is provided with a guide block matched with the guide groove.

In some embodiments of the present invention, the guide groove has a spiral shape; when the guide block is positioned at one end of the guide groove, the liquid discharge hole is communicated with the liquid passing hole; when the guide block is positioned at the other end of the guide groove, the liquid discharge hole and the liquid passing hole are closed.

In some embodiments of the present invention, a limiting ring is further included between the sliding sleeve and the fixing sleeve.

In some embodiments of the present invention, the control mechanism includes a core shaft, a locking assembly abutting against the sliding sleeve, and a limiting assembly for controlling the locking assembly to open and close, the locking assembly includes an elastic member and a locking block, and the locking block is connected to the core shaft through the elastic member; the limiting component is sleeved on the mandrel.

In some embodiments of the present invention, an annular groove is formed on an inner side wall of the sliding sleeve, and the locking block abuts against the annular groove.

In some embodiments of the present invention, the limiting assembly includes a limiting spring, a limiting sleeve and a limiting joint connected to the core shaft, the limiting spring and the limiting sleeve are both sleeved on the core shaft, and the limiting sleeve and the limiting joint are respectively disposed at two ends of the limiting spring.

In some embodiments of the present invention, an installation groove is formed along a length direction of the mandrel, the elastic member and the locking block are both installed in the installation groove, and an installation cavity is formed between the limiting sleeve and the installation groove.

In some embodiments of the invention, the number of the limiting components is two, and the two limiting components are respectively symmetrically disposed on two sides of the locking block.

In some embodiments of the invention, the elastic member comprises a leaf spring.

Compared with the prior art, the embodiment of the invention at least has the following advantages or beneficial effects:

the embodiment of the application provides a fracturing device suitable for coal bed gas exploitation, its including have the fixed sleeve of outage, have the sliding sleeve of liquid hole and be used for controlling the outage and cross the control mechanism that the liquid hole is linked together, in the fixed sleeve was located to the sliding sleeve slip cap, the outage was equipped with on the liquid hole with crossing and seals up the jam.

When the fracturing device is used practically, a production sleeve is put into a stratum with a plurality of layers of coal seams, the production sleeve is put to a designed position, cementing and well cementation are carried out, when fracturing construction is needed according to the position of the coal seam, a matched control mechanism is put into the stratum, the control mechanism moves to a sliding sleeve and then throws balls to the control mechanism to suppress pressure, the pressure pushes a limiting sleeve to be separated towards two sides through a pressure transmission channel to pressurize, a locking block is clamped in an annular clamping groove in the sliding sleeve after expanding, the control mechanism is lifted by pressurizing, the sliding sleeve moves upwards, and a liquid passing hole of the sliding sleeve is aligned with a liquid discharging hole of a fixing sleeve. The blocking plug in the liquid passing hole and the liquid discharging hole is broken under pressure, the liquid passing hole is communicated with the liquid discharging hole, the pressure of a well head is relieved, the limiting sleeve is reset under the action of a limiting spring, the locking block retracts into the mounting groove, and the control mechanism is taken out; then carry out the fracturing operation through crossing liquid hole and outage, when needing to close, go into control mechanism again and reach fixed sleeve's upper end, throw the ball pressurization to control mechanism again, pressure promotes spacing sleeve through passing pressure passageway pressurization and parts to both sides for the locking piece card after expanding is in the ring groove of sliding sleeve in, pushes down control mechanism, and sliding sleeve is down, makes sliding sleeve cross the liquid hole and stagger with fixed sleeve's flowing back hole, and the pressure release passageway is closed. The control mechanism is repeatedly lifted and lowered in this way, and the fracturing device is opened and closed for multiple times.

Drawings

To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are required to be used in the embodiments will be briefly described below, and it should be understood that the following drawings only illustrate some embodiments of the present invention, and therefore should not be considered as limiting the scope. For a person skilled in the art, it is possible to derive other relevant figures from these figures without inventive effort.

FIG. 1 is a schematic cross-sectional view of the assembled fracturing apparatus of the present invention;

FIG. 2 is a schematic sectional view of the assembled fixed sleeve and sliding sleeve of the embodiment of the present invention;

FIG. 3 is a schematic cross-sectional view of an assembled control mechanism in an embodiment of the present invention;

fig. 4 is a schematic structural diagram of the latch block after being ejected according to the embodiment of the present invention.

Icon: 100. fixing the sleeve; 101. a drain hole; 110. a sliding sleeve; 111. a liquid passing hole; 112. an annular neck; 120. blocking; 130. a guide block; 140. a seal ring; 141. a limiting ring; 151. a mandrel; 152. an elastic member; 153. a locking block; 154. a limiting spring; 155. a limiting sleeve; 156. a limiting joint; 157. and (7) installing a groove.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be obtained by a person skilled in the art without inventive step based on the embodiments of the present invention, are within the scope of protection of the present invention.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

In the description of the embodiments of the present invention, it should be noted that, if the terms "upper", "lower", "inner", "outer", etc. are used for indicating the orientations or positional relationships based on the orientations or positional relationships shown in the drawings or the orientations or positional relationships which are usually arranged when the products of the present invention are used, the terms are only used for convenience of describing the present invention and simplifying the description, but do not indicate or imply that the devices or elements which are indicated must have specific orientations, be constructed in specific orientations, and operate, and therefore, the present invention should not be construed as being limited.

In the description of the embodiments of the present invention, it should be further noted that unless otherwise explicitly stated or limited, the terms "disposed," "mounted," "connected," and "connected" should be interpreted broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

Example 1

Referring to fig. 1 to 4, the present embodiment provides a fracturing device suitable for coal bed methane mining, which includes a fixed sleeve 100 having a drainage hole 101, a sliding sleeve 110 having a liquid passing hole 111, and a control mechanism for controlling the communication between the drainage hole 101 and the liquid passing hole 111, wherein the sliding sleeve 110 is slidably sleeved in the fixed sleeve 100, and a sealing plug 120 is disposed on the drainage hole 101 and the liquid passing hole 111.

In this embodiment, the upper part and the lower part of the fixing sleeve 100 are both provided with connecting threads, which are mainly used for connecting with a construction casing in a pipeline; the inside cover of fixed sleeve 100 is equipped with sliding sleeve 110, is provided with 3 outage 101 along the circumference of fixed sleeve 100, is provided with 3 liquid holes 111 in the circumference of sliding sleeve 110 likewise, and outage 101 and liquid holes 111 are respectively one-to-one, all are fixed with shutoff stopper 120 through the locking spring in outage 101 and liquid holes 111 simultaneously, and its purpose is when preventing the well cementation, and the cement blocks up outage 101, and then influences the switch of fracturing unit. The upper end and the lower end of the inner side wall of the sliding sleeve 110 are both provided with an annular clamping groove 112; the ring-shaped slot 112 is abutted against a control mechanism, and the control mechanism can adjust the position relationship between the sliding sleeve 110 and the fixed sleeve 100, so as to control the liquid discharge hole 101 and the liquid through hole 111 to be communicated or staggered (i.e. closed).

A guide groove is formed on the inner side wall of the fixed sleeve 100, and a guide block 130 is formed on the outer side wall of the sliding sleeve 110; the guide block 130 can slide along the path of the guide groove; this ensures that the sliding sleeve 110 slides more smoothly within the fixed sleeve 100; meanwhile, in order to reduce the noise generated when the sliding sleeve and the fixed sleeve slide with each other, four sets of sealing rings 140 are arranged between the sliding sleeve 110 and the fixed sleeve 100; wherein, the two groups of sealing rings 140 are V-shaped sealing rings 140 which are respectively arranged at the upper and lower sides of the liquid discharge hole 101 of the fixed sleeve 100; the other two sets of seal rings 140 are O-ring seals 140, and are disposed at the upper and lower ends of the sliding sleeve 110, respectively. In addition, in order to ensure that the drain hole 101 of the fixed sleeve 100 is opened or closed only under the action of the control mechanism, a limiting ring 141 is provided on the sliding sleeve 110, and the limiting ring 141 is located between the sliding sleeve 110 and the fixed sleeve 100. When the drain hole 101 is in a closed state, the stopper ring 141 is locked in an annular groove at a lower portion of the fixed sleeve 100, and position fixation between the sliding sleeve 110 and the fixed sleeve 100 is achieved. Only when the drain hole 101 needs to be opened, the locking block 153 of the control mechanism expands and locks and is pulled upwards to a certain tonnage in the sliding sleeve 110, and the limiting ring 141 is pulled out of the annular groove at the lower end in the fixed sleeve 100 and ascends to the annular groove at the upper end. When the liquid passing hole 111 of the sliding sleeve 110 is communicated with the liquid discharge hole 101 of the fixed sleeve 100, the sliding sleeve 110 and the fixed sleeve 100 cannot move freely in the axial direction due to friction of the limiting ring 141, so that the position of the sliding sleeve 110 in the fixed sleeve 100 is fixed. The limiting ring 141 can be a snap spring and a limiting block made of elastic material, such as an elastic rubber ring)

The control mechanism is sleeved in the sliding sleeve 110 and comprises a mandrel 151, a locking assembly and a limiting assembly, the locking assembly comprises an elastic piece 152 and a locking block 153, and the locking block 153 is connected with the mandrel 151 through the elastic piece 152; the locking block 153 is opened under the elastic force of the elastic member 152 and is abutted to the annular clamping groove 112 of the sliding sleeve 110, so that people can conveniently adjust the position relation between the sliding sleeve 110 and the fixed sleeve 100 through the clamping fit of the locking block 153 and the annular clamping groove 112, and further control the liquid discharge hole 101 to be communicated with or staggered (namely closed) with the liquid passing hole 111. The limiting component is sleeved on the mandrel 151 and is mainly used for controlling the locking component to be opened and closed, namely controlling whether the locking block 153 is popped up or not. A pressure transmission channel is arranged in the mandrel 151, a ball seat is arranged in the bottom end of the mandrel 151, and the mandrel 151 and the ball seat are fixed together through a shearing pin. Petals are milled at one end, far away from the mandrel 151, of the ball seat, so that overflowing is facilitated. An installation groove 157 is formed in the middle of the mandrel 151 along the length direction of the mandrel 151, one end of the elastic member 152 is arranged in the installation groove 157, the other end piece of the elastic member 152 is connected with the locking block 153, the elastic member 152 and the locking block 153 are both limited in the installation groove 157 of the mandrel 151 by the limiting assembly, and at the moment, the elastic member 152 is in a compression state. The elastic member 152 may be a flat spring, which is the simplest spring having a spring characteristic by using deformation of an elastic metal sheet. The elastic metal sheet has a rectangular shape, a trapezoidal shape and a triangular shape, and can also be a straight sheet or a bent sheet. The device is generally used in places with smaller load and deformation and low rigidity requirements, such as sensitive elements, elastic supports or positioning devices in instruments, meters and automation mechanisms.

In some other embodiments, the elastic member 152 may also be made of rubber, which is a high-elasticity polymer material with reversible deformation, and is elastic at room temperature, and can generate large deformation under the action of small external force, and can recover to the original shape after the external force is removed.

The two sets of limiting components are symmetrically arranged on the upper side and the lower side of the locking block 153 respectively. Two sets of spacing subassemblies all include spacing spring 154, spacing sleeve 155 and spacing joint 156, spacing joint 156 and dabber 151 threaded connection, spacing spring 154 and spacing sleeve 155 all overlap locate on dabber 151, spacing sleeve 155 and spacing joint 156 locate the both ends of spacing spring 154 respectively, form the installation cavity between spacing sleeve 155 and the mounting groove 157, elastic component 152 and locking piece 153 are all hidden in the installation cavity, make whole control mechanism can freely overlap and establish inside sliding sleeve 110. After the limiting spring 154 is pushed and compressed by hydraulic pressure, the locking block 153 is ejected out of the mounting groove 157 under the elastic force of the elastic member 152, and abuts against the sliding sleeve 110, so that the locking block is connected with the sliding sleeve 110 by being clamped into the annular clamping groove 112. Wherein, the limit joint 156 connected with the top of the mandrel 151 is provided with taper threads for connecting with an oil pipe; wherein a stopper joint 156 connected to the end of the mandrel 151 is provided with an overflowing hole.

When the device is used, the specific steps are as follows:

1. before the device is put into the well, the well is required to be fully communicated, scraped and washed;

2. the device and the casing are put into a well together, after the fracturing device is put into the well, the casing is internally circulated, acid soluble cement slurry is added to the outside of the fixed sleeve 100, and annular well cementation operation of the casing, the device and the shaft is carried out.

3. After the well cementation construction is finished, feeding a rubber plug for replacing slurry, wherein the rubber plug reaches a short section of a lower collision pressing seat through a fracturing tool to be collided and pressed;

4. a matched control mechanism is put into the coiled tubing;

5. and filling clear water into the pipe, pumping a blocking ball into the wellhead, and pressurizing the wellhead by 70MPa after the pressure is raised to perform the tightness test and the functional test of the tool on the pipe string. After the test is passed, the limit joint 156 connected to the tail of the mandrel 151 is removed, and the blocking ball is taken out;

6. lowering the control mechanism below the fixed sleeve 100 again, and performing positive circulation well flushing until the inlet and outlet liquid properties are consistent;

7. lifting and lowering the coiled tubing twice, and recording the lifting tension and the lowering tension;

8. and throwing the blocking ball into the pipe, and pumping the blocking ball to fall into place.

9. Opening operation: the pressure is positively pressed to 7.0MPa, the coiled tubing is slowly lifted up under the state of keeping the pressure to observe the tension change at any time, and when the tension continuously rises and displays, the liquid discharge hole 101 and the liquid passing hole 111 can be judged to be communicated and are completely opened;

10. closing operation: and (3) positively pressurizing to 7.0MPa, slowly lifting the coiled tubing under the state of keeping the pressure to observe the tension change at any time, and judging that the control mechanism is clamped with the annular clamping groove 112 of the sliding sleeve 110 when the tension continuously rises and is displayed. Slowly lowering the pipe column to apply a pushing force of 10-30KN, and judging that the liquid discharge hole 101 and the liquid through hole 111 are staggered and are completely closed when the tension of the equipment is continuously reduced and displayed;

11. the pressure in the pipe is relieved to zero, and when the tension of the up-down moving coiled tubing is not changed, the control mechanism and the annular clamping groove 112 of the sliding sleeve 110 are unlocked.

12. The control mechanism is lifted to a safe depth within the wellbore (straight section) or out of the wellhead.

Example 2

The present embodiment proposes, based on the technical solution of embodiment 1: the guide groove is spiral; when the guide block 130 is positioned at one end of the guide groove, the liquid discharge hole 101 is communicated with the liquid passing hole 111; when the guide block 130 is located at the other end of the guide groove, the liquid discharge hole 101 and the liquid passing hole 111 are closed.

In this embodiment, the guiding slot is spiral, and at the initial position, the guiding block 130 is located at one end of the guiding slot, and at this time, the liquid discharging hole 101 is not communicated with the liquid passing hole 111, and is in a closed state; when the guide block 130 moves to the other end of the guide groove, the liquid discharge hole 101 is communicated with the liquid passing hole 111 and is in an open state; when the sliding sleeve 110 slides in the fixed sleeve 100 through the guide groove, the mutual communication and mutual closing free switching between the liquid discharge hole 101 and the liquid passing hole 111 can be conveniently and quickly realized.

In summary, the embodiment of the present invention provides a fracturing device suitable for coal bed gas exploitation, which includes a fixed sleeve 100 having a liquid drainage hole 101, a sliding sleeve 110 having a liquid passing hole 111, and a control mechanism for controlling the liquid drainage hole 101 to communicate with the liquid passing hole 111, wherein the sliding sleeve 110 is slidably sleeved in the fixed sleeve 100, and the liquid drainage hole 101 and the liquid passing hole 111 are provided with plugs 120.

In exploitation, fracturing refers to a method of forming a fracture in an oil and gas layer by using the action of water power in the process of oil or gas production, and is also called as hydraulic fracturing. Fracturing is the process of artificially cracking stratum, improving the flowing environment of oil or gas underground, increasing the yield of oil or gas, and playing an important role in improving the flowing condition of oil well bottom, slowing down the intervals and improving the oil layer using condition.

In actual use, in a stratum with a plurality of layers of coal seams, a production casing is put in, after the production casing is put at a designed position, cementing and well cementation are carried out, when fracturing construction is needed according to the position of the coal seam, a matched control mechanism is put in, after the control mechanism moves to the sliding sleeve 110, the control mechanism is thrown and pressed, pressure is applied through a pressure transmission channel to push the limiting sleeve 155 to separate towards two sides, the locking block 153 is clamped in the annular clamping groove 112 in the sliding sleeve 110 after expanding, the control mechanism is lifted by applying pressure, the sliding sleeve 110 moves upwards, and the liquid passing hole 111 of the sliding sleeve 110 is aligned with the liquid discharge hole 101 of the fixed sleeve 100. The liquid passing hole 111 and the sealing plug 120 in the liquid discharge hole 101 are broken under pressure, the liquid passing hole 111 is communicated with the liquid discharge hole 101, the wellhead is decompressed, the limiting sleeve 155 is reset under the action of the limiting spring 154, the locking block 153 retracts into the mounting groove 157, and the control mechanism is taken out; then carry out the fracturing operation through crossing liquid hole 111 and outage 101, when needing to close, go into control mechanism again and reach the upper end of fixed sleeve 100, add the ball pressurization to control mechanism again, pressure pushes away spacing sleeve 155 through the pressurization of biography pressure passageway and parts to both sides for block 153 rises back card in the ring groove 112 in sliding sleeve 110, pushes down control mechanism, sliding sleeve 110 descends, makes the liquid hole 111 of crossing of sliding sleeve 110 and the outage 101 of fixed sleeve 100 stagger mutually, and the pressure release passageway is closed. The control mechanism is repeatedly lifted and lowered in this way, and multiple opening and closing of the fracturing device are realized.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention. Various modifications and alterations to this invention will become apparent to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The utility model provides a fracturing device suitable for coal bed gas exploitation which characterized in that: the sliding sleeve is sleeved in the fixed sleeve in a sliding mode, the liquid drainage hole and the liquid drainage hole are provided with plugs, the control mechanism comprises a core shaft, a locking assembly and a limiting assembly, the locking assembly abuts against the sliding sleeve, the limiting assembly is used for controlling the locking assembly to be opened and closed, the locking assembly comprises an elastic piece and a locking block, and the locking block is connected with the core shaft through the elastic piece; the limiting assembly is sleeved on the mandrel, an annular clamping groove is formed in the inner side wall of the sliding sleeve, and the locking block is abutted to the annular clamping groove.

2. The fracturing device suitable for coal bed gas exploitation of claim 1, wherein: the inner side wall of the fixed sleeve is provided with a guide groove, and the outer side wall of the sliding sleeve is provided with a guide block matched with the guide groove.

3. A fracturing device suitable for coal bed methane exploitation according to claim 2, wherein: the guide groove is spiral; when the guide block is positioned at one end of the guide groove, the liquid discharge hole is communicated with the liquid passing hole; and when the guide block is positioned at the other end of the guide groove, the liquid discharge hole and the liquid passing hole are closed.

4. The fracturing device suitable for coal bed gas exploitation of claim 1, wherein: the sliding sleeve is arranged on the fixed sleeve, and the limiting ring is arranged between the sliding sleeve and the fixed sleeve.

5. The fracturing device suitable for coal bed gas exploitation of claim 1, wherein: the limiting assembly comprises a limiting spring, a limiting sleeve and a limiting joint connected with the core shaft, the limiting spring and the limiting sleeve are all sleeved on the core shaft, and the limiting sleeve and the limiting joint are respectively arranged at two ends of the limiting spring.

6. A fracturing device suitable for coal bed gas exploitation according to claim 5, wherein: the edge the dabber length direction has seted up the mounting groove, the elastic component with the locking piece all install in the mounting groove, spacing sleeve with form the installation cavity between the mounting groove.

7. A fracturing device suitable for coal bed gas exploitation according to claim 6, wherein: the limiting assemblies are two groups, and the two groups of limiting parts are symmetrically arranged on two sides of the locking block respectively.

8. The fracturing device suitable for coal bed gas exploitation of claim 1, wherein: the elastic member includes a leaf spring.