CN219639333U - Three-stage damping structure of cogeneration unit - Google Patents

Abstract

The utility model discloses a three-stage damping structure of a cogeneration unit, which comprises a mounting plate fixedly connected to the bottom of the cogeneration unit. According to the utility model, through the first damping buffer component, the pneumatic damping buffer component, the inner pipe, the outer pipe and the second damping buffer component, the three-level damping unloading force is conveniently carried out on the combined heat and power generation unit when the hard vibration force is large, the downward transmission of the hard vibration impact force is relieved, the hard vibration impact noise generated with the ground is reduced, and the arrangement of the telescopic dustproof rubber sleeves is combined, so that each group of dustproof integrated dismounting type three-level damping structure bodies forming three-level damping are integrated inside and are dustproof and protected, the pollution of external impurities and greasy dirt to each damping part is prevented, the protection effect and the long-term use stability are improved, the integration is high, the rotary knob type quick-fixing bolt is matched for convenient installation and fixation, the convenient dismounting is convenient, and the dismounting and replacement efficiency of the dustproof integrated dismounting type three-level damping structure bodies during damage is improved.

Description

Three-stage damping structure of cogeneration unit

Technical Field

The utility model relates to the technical field of cogeneration units, in particular to a three-stage damping structure of a cogeneration unit.

Background

Cogeneration, also known as cogeneration, is a production mode of simultaneously generating electric power and useful heat by using a heat engine or a power station, wherein the power station not only generates electric energy, but also supplies heat to users by using steam generated by a turbine generator, and is called a cogeneration unit; in the existing cogeneration unit, when an engine runs at high speed and drives a generator to work through a coupler, high-frequency hard vibration is generated, and hard vibration impact noise with the ground is generated through a base, so that a damping structure is needed to damp and unload force;

publication number CN211343860U discloses a three-stage damping structure of a cogeneration unit, which comprises a cogeneration unit base, an engine, a generator, a public base, a first-stage damper, a closed sound-proof housing, a second-stage damper, a VE-type damper, and a third-stage damper; the engine and the generator are fixed on a public base, and a primary shock absorber is arranged between the lower part of the public base and the upper part of the cogeneration unit base; the closed sound-proof housing is arranged on the cogeneration unit base, and a secondary shock absorber is arranged between the four corners of the bottom of the closed sound-proof housing and the four corners of the upper surface of the cogeneration unit base; the middle upper parts of the four outer side surfaces of the closed sound-proof housing are provided with VE-type shock absorbers; three-stage shock absorbers are uniformly distributed at four corners below the base of the cogeneration unit. Through setting up tertiary shock-absorbing structure, it is more reasonable in structural aspect, simple to operate is swift, and the shock attenuation falls the noise effect well, and elasticity shock-absorbing system distributes evenly, has realized shock attenuation, has inhaled the effect of making an uproar, falls better.

The above-mentioned patent realizes the tertiary shock attenuation to cogeneration unit through cooperation such as one-level bumper shock absorber, second grade bumper shock absorber and tertiary bumper shock absorber, but it still has some not enough:

1. the structure of the shock absorber is directly arranged outside in a leaking way, and under long-term use, shock absorber parts are easily polluted by impurity greasy dirt and the like, so that long-term safe use is influenced, and the protection effect is not ideal; 2. in addition, each grading damper forming three-level damping is arranged at different positions, the integration of parts forming three-level damping in each group is not ideal, the installation positions are more, the operation is complicated, the disassembly and the assembly are inconvenient, and the disassembly and the replacement efficiency are poor when damaged; in combination with the above phenomena, we propose a three-stage damping structure of a cogeneration unit for solving the above problems.

Disclosure of Invention

The utility model aims to provide a three-stage damping structure of a cogeneration unit, which aims to solve the problems in the background art.

In order to achieve the above purpose, the present utility model provides the following technical solutions: the three-level damping structure of the cogeneration unit comprises a mounting plate fixedly connected to the bottom of the cogeneration unit, wherein a bottom plate is arranged below the mounting plate, and four dustproof integrated dismounting three-level damping structure bodies are arranged between the top of the bottom plate and the bottom of the mounting plate;

the utility model provides a dustproof integrative reassembling type tertiary shock-absorbing structure body is including installing the annular slab at the bottom plate top, and annular slab internal fixation cover is equipped with the outer tube that the bottom is the plugging structure, and the bottom plate activity cutting ferrule is on four outer tubes, the intraductal slip cap is equipped with the inner tube that the top is the plugging structure, and the top of inner tube is equipped with the fixed plate of installing plate bottom, fixedly connected with flexible dustproof gum cover between the bottom of fixed plate and the top of corresponding annular slab, the bottom fixedly connected with of fixed plate is located the first damping buffer subassembly that corresponds flexible dustproof gum cover, and first damping buffer subassembly is used for carrying out preliminary damping buffering shock attenuation when the cogeneration unit shakes and unloads the power, and the bottom fixedly connected with pneumatic damping buffer subassembly of first damping buffer subassembly is used for carrying out secondary damping buffering shock attenuation when the hard impact force is great, and pneumatic damping buffer subassembly is installed in the inner tube that corresponds, the intraductal internal fixation cover is equipped with second damping buffer subassembly, and the bottom of second damping buffer subassembly and the bottom inner wall fixedly connected with of the outer tube that corresponds.

Preferably, the first damping buffer component comprises two guide posts and two elastic damping rubber sleeves which are fixedly connected to the bottoms of the corresponding fixing plates, the elastic damping rubber sleeves are movably sleeved on the corresponding guide posts, the bottoms of the two elastic damping rubber sleeves positioned at the bottoms of the same fixing plate are fixedly adhered with the same connecting plate, the connecting plate is slidably sleeved on the corresponding two guide posts, and the connecting plate and the elastic damping rubber sleeves are both positioned in the corresponding telescopic dustproof rubber sleeves; the guide post, the elastic damping gum cover and the connecting plate that set up cooperate, when the cogeneration unit vibrations drive mounting panel hard shake downwards, the mounting panel drives the guide post through corresponding fixed plate and moves downwards to the extrusion of elastic damping gum cover, utilize the elastic damping gum cover to realize preliminary damping and unload the power, reduce the hard shake impact force of downward transmission.

Preferably, the pneumatic damping buffer component comprises two guide pipes fixedly connected to the bottoms of the corresponding connecting plates, the guide pipes are sleeved on the corresponding guide posts in a sliding manner, the bottom ends of the two guide pipes positioned on the same connecting plate extend into the inner pipe and are fixedly connected with the same piston, the piston is sleeved in the corresponding inner pipe in a sealing manner, and the inner pipe is sleeved on the corresponding two guide pipes in a sliding manner; the guide tube and the piston are matched, when the elastic damping rubber sleeve is extruded to drive the corresponding connecting plate to move downwards, the connecting plate drives the piston to move downwards through the corresponding guide tube, the piston compresses gas inside the inner tube, and when the hard vibration force is large, the compressed gas is utilized to realize secondary damping to relieve the hard vibration force.

Preferably, the second damping buffer component comprises a plugging plate fixedly installed in the corresponding inner pipe, the plugging plate is positioned below the corresponding piston and matched with the piston, and two spring damping dampers are fixedly connected between the bottom of the plugging plate and the bottom end inner wall of the corresponding outer pipe; the sealing plate and the spring damping damper are matched, the hard vibration force is large, when the piston compresses the gas in the corresponding inner pipe downwards, the piston drives the corresponding sealing plate to move downwards through compressed gas, the sealing plate compresses the corresponding spring damping damper, and the spring damping damper is utilized to realize three-time damping when the hard vibration force is large, so that the hard vibration force is relieved.

Preferably, the top of the bottom plate is rectangular, four positioning slots are formed in the top of the bottom plate, and the positioning slots are movably sleeved on the corresponding outer tubes.

Preferably, four clamping grooves are formed in the bottom of the mounting plate in a rectangular shape, clamping blocks are fixedly connected to the top of the fixing plate, and the clamping blocks are movably clamped in the corresponding clamping grooves.

Preferably, eight thread grooves are formed in one side, close to the mounting plate, of the bottom plate, knob type quick-fixing bolts are sleeved in the thread grooves in a threaded mode, and the annular plate and the fixing plate are respectively sleeved on the two corresponding knob type quick-fixing bolts in a threaded mode.

Compared with the prior art, the utility model has the beneficial effects that:

1. according to the three-level damping structure of the cogeneration unit, the first damping buffer component, the air pressure damping buffer component, the inner pipe, the outer pipe and the second damping buffer component are matched, so that when the cogeneration unit vibrates to drive the mounting plate to hard shake downwards, three-level damping buffer can be sequentially realized on the hard shake force from top to bottom, the effect of three-level damping and unloading force is realized, the downward-transmitted hard shake impact force is relieved, and the hard shake impact noise generated with the ground is reduced;

2. this tertiary shock-absorbing structure of cogeneration unit, flexible dustproof gum cover in the tertiary shock-absorbing structure body self outside of dustproof integrative reassembling type, realize forming the damping shock-absorbing part an organic whole of the tertiary shock-absorbing structure body of tertiary shock-absorbing of each group and integrate inside and prevent to prevent that external impurity and greasy dirt from fouling each damping part, improve protection effect and long-term stability in use, and the inheritance of the tertiary shock-absorbing structure body of the dustproof integrative reassembling type of each group is high, need not to separately install tertiary shock attenuation step by step, thereby reduce mounted position, the mode of convenient installation and fixation of the quick bolt of the knob formula of re-coordination utilization, the convenience is changed the dismouting of the tertiary shock-absorbing structure body of dustproof integrative reassembling type when damaging fast.

According to the utility model, through the first damping buffer component, the pneumatic damping buffer component, the inner pipe, the outer pipe and the second damping buffer component, the three-level damping unloading force is conveniently carried out on the combined heat and power generation unit when the hard vibration force is large, the downward transmission of the hard vibration impact force is relieved, the hard vibration impact noise generated with the ground is reduced, and the arrangement of the telescopic dustproof rubber sleeves is combined, so that each group of dustproof integrated dismounting type three-level damping structure bodies forming three-level damping are integrated inside and are dustproof and protected, the pollution of external impurities and greasy dirt to each damping part is prevented, the protection effect and the long-term use stability are improved, the integration is high, the rotary knob type quick-fixing bolt is matched for convenient installation and fixation, the convenient dismounting is convenient, and the dismounting and replacement efficiency of the dustproof integrated dismounting type three-level damping structure bodies during damage is improved.

Drawings

FIG. 1 is a schematic overall perspective view of the present utility model;

FIG. 2 is a schematic diagram of a front view structure of the present utility model;

fig. 3 is an enlarged schematic view of the structure of fig. 2, partially cut-away, according to the present utility model.

In the figure: 100. a mounting plate; 101. a cogeneration unit; 200. a bottom plate; 201. positioning the slot; 1. an outer tube; 2. an annular plate; 3. a fixing plate; 4. an inner tube; 5. a telescopic dustproof rubber sleeve; 6. a plugging plate; 7. a spring shock absorber; 8. a piston; 9. a guide tube; 10. a guide post; 11. a connecting plate; 12. an elastic damping rubber sleeve; 13. knob type quick fixing bolt; 14. and (5) clamping blocks.

Detailed Description

The following description of the embodiments of the present utility model will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present utility model, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

As shown in fig. 1 to 3, the three-stage damping structure of a cogeneration unit provided in this embodiment includes a mounting plate 100 fixedly connected to the bottom of the cogeneration unit 101, a bottom plate 200 is disposed below the mounting plate 100, and four dust-proof integrated detachable three-stage damping structure bodies are mounted between the top of the bottom plate 200 and the bottom of the mounting plate 100;

the dustproof integrated dismounting type three-stage shock-absorbing structure body comprises an annular plate 2 arranged at the top of a bottom plate 200, an outer tube 1 with the bottom of the annular plate 2 being of a plugging structure is fixedly sleeved on the inner wall of the right side of the outer tube 1, a fixing plate 3 arranged at the bottom of a mounting plate 100 is movably sleeved on the four outer tubes 1, four positioning slots 201 are formed in the top of the bottom plate 200 in a rectangular mode, the positioning slots 201 are movably sleeved on the corresponding outer tube 1, the effect of conveniently clamping and positioning the outer tube 1 is achieved, an inner tube 4 with the top of the plugging structure is fixedly sleeved on the inner tube 1, a limit groove is formed in the right side of the inner tube 4, a limit block which is in sliding connection with the corresponding limit groove is fixedly connected on the right side inner wall of the outer tube 1, the limit groove is used for limiting and preventing the inner tube 4 from falling off is arranged above the inner tube 4, a clamping plate 3 is arranged at the bottom of the mounting plate 100, four clamping grooves are formed in the bottom of the mounting plate 100, clamping blocks 14 are fixedly connected at the top of the fixing plate 3, the clamping blocks 14 are movably clamped in the corresponding clamping grooves, the effect of conveniently clamping and positioning the fixing plate 3 is achieved, a dustproof rubber sleeve 5 is fixedly connected between the bottom of the fixing plate 3 and the top of the corresponding annular plate 2, a screw bolt 3 is fixedly connected with the bottom plate 200 and the corresponding screw hole 13, the screw hole is fixedly connected with the screw hole 13 is formed in the screw hole 13, and the screw hole 13 is fixedly connected with the screw hole 13, and the screw hole 13 is formed in the screw hole 3 is correspondingly in the screw hole type bolt 3, and the screw hole type quick bolt is fixedly corresponds to the screw hole type bolt 3 and the screw hole type bolt 3;

the bottom of the fixed plate 3 is fixedly connected with a first damping buffer component positioned in the corresponding telescopic dustproof rubber sleeve 5, and the first damping buffer component is used for performing primary damping buffer damping force unloading when the cogeneration unit 101 vibrates; the first damping buffer component comprises two guide posts 10 and two elastic damping rubber sleeves 12 which are fixedly connected to the bottoms of the corresponding fixed plates 3, the elastic damping rubber sleeves 12 are movably sleeved on the corresponding guide posts 10, the bottoms of the two elastic damping rubber sleeves 12 which are positioned at the bottoms of the same fixed plates 3 are fixedly adhered with the same connecting plate 11, the connecting plate 11 is slidably sleeved on the corresponding two guide posts 10, two guide holes which are respectively in sliding contact with the outer sides of the corresponding guide posts 10 are formed in the bottoms of the connecting plate 11, the connecting plate 11 is slidably sleeved on the corresponding two guide posts 10 through the two guide holes, the effect of vertically sliding and guiding the guide posts 10 is achieved, and the connecting plate 11 and the elastic damping rubber sleeves 12 are positioned in the corresponding telescopic dustproof rubber sleeves 5; the guide post 10, the elastic damping rubber sleeve 12 and the connecting plate 11 are matched, when the cogeneration unit 101 vibrates to drive the mounting plate 100 to shake downwards and hard, the mounting plate 100 drives the guide post 10 to move downwards through the corresponding fixing plate 3 and extrudes the elastic damping rubber sleeve 12, and the elastic damping rubber sleeve 12 is used for realizing preliminary damping force unloading to reduce the downward-transmitted hard shake impact force;

the bottom of the connecting plate 11 is fixedly connected with an air pressure damping buffer assembly, the air pressure damping buffer assembly is used for carrying out secondary damping buffer unloading when the rigid impact shock force is large, and the air pressure damping buffer assembly is sealed and sleeved in the corresponding inner tube 4; the pneumatic damping buffer assembly comprises two guide pipes 9 fixedly connected to the bottoms of corresponding connecting plates 11, the guide pipes 9 are slidably sleeved on corresponding guide posts 10, the bottom ends of the two guide pipes 9 positioned on the same connecting plate 11 extend into the inner pipe 4 and are fixedly connected with the same piston 8, the piston 8 is sleeved in the corresponding inner pipe 4, the piston 8 can slide in the vertical direction on the inner side wall of the inner pipe 4 when receiving force in the vertical direction, the inner pipe 4 is slidably sleeved on the corresponding two guide pipes 9, two vertical guide holes which are respectively in sliding contact with the outer sides of the corresponding guide pipes 9 are formed in the inner wall of the top end of the inner pipe 4, and the inner pipe 4 is slidably sleeved on the two guide pipes 9 through the two vertical guide holes so as to achieve the effect of vertically slidably guiding the guide pipes 9; the guide pipe 9 is matched with the piston 8, when the elastic damping rubber sleeve 12 is extruded to drive the corresponding connecting plate 11 to move downwards, the connecting plate 11 drives the piston 8 to move downwards through the corresponding guide pipe 9, the piston 8 compresses the gas in the inner pipe 4, and when the hard vibration force is large, the compressed gas is utilized to realize secondary damping to release the hard vibration force;

the inner tube 4 is fixedly sleeved with a second damping buffer assembly, the bottom of the second damping buffer assembly is fixedly connected with the inner wall of the bottom of the corresponding outer tube 1, and the second damping buffer assembly is used for performing three damping buffer force unloading when the rigid impact shock force is large; the second damping buffer component comprises a blocking plate 6 fixedly installed in the corresponding inner pipe 4, the blocking plate 6 is located below the corresponding piston 8 and is matched with the piston 8, the bottom of the inner side of the inner pipe 4 is fixedly blocked by the blocking plate 6, so that a sealing space is formed between the top of the blocking plate 6 and the bottom of the piston 8, gas in the sealing space is high-pressure gas, and two spring damping dampers 7 are fixedly connected between the bottom of the blocking plate 6 and the inner wall of the bottom end of the corresponding outer pipe 1; the arranged plugging plates 6 are matched with the spring damping dampers 7, when the hard vibration force is large, and when the piston 8 compresses the gas in the corresponding inner pipe 4 downwards, the piston 8 drives the corresponding plugging plates 6 to move downwards through the compressed gas, the plugging plates 6 compress the corresponding spring damping dampers 7, and the spring damping dampers 7 are utilized to realize three damping to relieve the hard vibration force when the hard vibration force is large; the telescopic dustproof rubber sleeve 5 is used for shielding dust outside and preventing dust impurities from entering between the structures inside the telescopic dustproof rubber sleeve.

The application method of the embodiment is as follows: when the cogeneration unit 101 vibrates to drive the mounting plate 100 to conduct downward hard vibration, the mounting plate 100 drives the guide post 10 to move downwards through the corresponding fixing plate 3 and extrudes the elastic damping rubber sleeve 12 and the telescopic dustproof rubber sleeve 5 to enable the elastic damping rubber sleeve 12 and the telescopic dustproof rubber sleeve 5 to be compressed, the elastic damping rubber sleeve 12 is utilized to achieve primary damping unloading force, the corresponding connecting plate 11 is driven to move downwards when the elastic damping rubber sleeve 12 is extruded, the connecting plate 11 drives the piston 8 to move downwards through the corresponding guide pipe 9, the piston 8 compresses high-pressure gas in the inner pipe 4, the compressed gas also extrudes the corresponding plugging plate 6 downwards, under the extrusion force, the plugging plate 6 moves downwards and compresses the corresponding spring damping damper 7, three-level damping unloading force of the cogeneration unit 101 is achieved under the cooperation that the elastic damping rubber sleeve 12, the gas and the spring damping damper 7 are sequentially compressed, and the hard vibration impact force is relieved, and the hard vibration impact noise generated with the ground is reduced;

in addition, the mode that each damping part set up in the flexible dustproof gum cover 5 that corresponds can prevent that outside impurity and greasy dirt from fouling to each damping part, improve the protection effect, thereby improve long-term stability in use, and each group forms the mode that the dustproof integrative reassembling type tertiary shock-absorbing structure body of tertiary shock attenuation all integrates and sets up in the flexible dustproof gum cover 5 that corresponds, the part integration nature of the dustproof integrative reassembling type tertiary shock-absorbing structure body of each group formation is high, and the cooperation carries out the mode of thread tightening through knob formula fast-fixing bolt 13, after follow-up simple reverse rotation knob formula fast-fixing bolt 13 is released fixedly, when upwards move mounting panel 100 makes its and four fixture blocks 14 separation, conveniently take off the three shock-absorbing structure body of dustproof integrative reassembling type that one damaged in four, utilize the mode of integration, the mounted position is few, convenient dismouting, the dismouting to the dismouting efficiency of the dismouting to the dustproof integrative tertiary shock-absorbing structure body of three-absorbing structure body of the time of improvement damage.

Finally, it should be noted that: the foregoing description is only a preferred embodiment of the present utility model, and the present utility model is not limited thereto, but it is to be understood that modifications and equivalents of some of the technical features described in the foregoing embodiments may be made by those skilled in the art, although the present utility model has been described in detail with reference to the foregoing embodiments. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present utility model should be included in the protection scope of the present utility model.

Claims (7)

1. The utility model provides a tertiary shock-absorbing structure of cogeneration unit, includes mounting panel (100) of fixed connection in cogeneration unit (101) bottom, its characterized in that: a bottom plate (200) is arranged below the mounting plate (100), and four dustproof integrated detachable three-level damping structure bodies are arranged between the top of the bottom plate (200) and the bottom of the mounting plate (100);

the utility model provides a dustproof integrative dismouting formula tertiary shock-absorbing structure body is including installing annular slab (2) at bottom plate (200) top, annular slab (2) internal fixation cover is equipped with outer tube (1) that the bottom is the shutoff structure, bottom plate (200) activity cutting ferrule is on four outer tubes (1), the slip cover is equipped with inner tube (4) that the top is the shutoff structure in outer tube (1), the top of inner tube (4) is equipped with fixed plate (3) of installing in mounting panel (100) bottom, fixedly connected with flexible dustproof gum cover (5) between the bottom of fixed plate (3) and the top of annular slab (2) that corresponds, the bottom fixedly connected with of fixed plate (3) is located the first damping buffer subassembly of flexible dustproof gum cover (5) that corresponds, the bottom fixedly connected with pneumatic damping buffer subassembly of first damping buffer subassembly, pneumatic damping buffer subassembly seal cartridge is in inner tube (4) that correspond, inner tube (4) internal fixation cover is equipped with second damping buffer subassembly, the bottom of second damping buffer subassembly and the bottom inner wall fixed connection of outer tube (1) that corresponds.

2. The three-stage damping structure of a cogeneration unit according to claim 1, wherein: the first damping buffer component comprises two guide posts (10) and two elastic damping rubber sleeves (12) which are fixedly connected to the bottoms of corresponding fixing plates (3), the elastic damping rubber sleeves (12) are movably sleeved on the corresponding guide posts (10), the bottoms of the two elastic damping rubber sleeves (12) which are positioned at the bottoms of the same fixing plates (3) are fixedly bonded with the same connecting plate (11), the connecting plate (11) is slidably sleeved on the corresponding two guide posts (10), and the connecting plate (11) and the elastic damping rubber sleeves (12) are both positioned in the corresponding telescopic dustproof rubber sleeves (5).

3. The three-stage damping structure of a cogeneration unit according to claim 2, wherein: the pneumatic damping buffer assembly comprises two guide pipes (9) fixedly connected to the bottoms of corresponding connecting plates (11), the guide pipes (9) are slidably sleeved on corresponding guide posts (10), the bottoms of the two guide pipes (9) located on the same connecting plate (11) are all extended into the inner pipe (4) and fixedly connected with the same piston (8), the piston (8) is sealed and sleeved in the corresponding inner pipe (4), and the inner pipe (4) is slidably sleeved on the corresponding two guide pipes (9).

4. A three-stage damping structure for a cogeneration unit according to claim 3, wherein: the second damping buffer component comprises a plugging plate (6) fixedly installed in the corresponding inner pipe (4), the plugging plate (6) is located below the corresponding piston (8) and matched with the piston (8), and two spring damping dampers (7) are fixedly connected between the bottom of the plugging plate (6) and the inner wall of the bottom end of the corresponding outer pipe (1).

5. The three-stage damping structure of a cogeneration unit according to claim 1, wherein: four positioning slots (201) are formed in the top of the bottom plate (200) in a rectangular shape, and the positioning slots (201) are movably sleeved on the corresponding outer tube (1).

6. The three-stage damping structure of a cogeneration unit according to claim 1, wherein: four clamping grooves are formed in the bottom of the mounting plate (100) in a rectangular shape, clamping blocks (14) are fixedly connected to the top of the fixing plate (3), and the clamping blocks (14) are movably clamped in the corresponding clamping grooves.

7. The three-stage damping structure of a cogeneration unit according to claim 1, wherein: eight thread grooves are formed in one side, close to the mounting plate (100), of the bottom plate (200), knob type quick-fixing bolts (13) are sleeved in the thread grooves in a threaded mode, and the annular plate (2) and the fixing plate (3) are sleeved on the two corresponding knob type quick-fixing bolts (13) in a threaded mode.