CN113217359B

CN113217359B - One-way diaphragm pump

Info

Publication number: CN113217359B
Application number: CN202110679503.6A
Authority: CN
Inventors: 熊颖申; 雷立强; 凌辉
Original assignee: Shenzhen Cnht Ltd
Current assignee: Shenzhen Cnht Ltd
Priority date: 2021-06-18
Filing date: 2021-06-18
Publication date: 2022-11-22
Anticipated expiration: 2041-06-18
Also published as: CN113217359A

Abstract

The invention discloses a one-way diaphragm pump, which comprises a motor and a pump body, wherein the motor is connected to the lower end of the pump body; the diaphragm is arranged above the base through a diaphragm support and is in transmission connection with an output shaft of the motor through an intermediate transmission mechanism; the water inlet valve plate and the water discharge valve plate are respectively arranged at the water inlet hole and the water discharge hole of the end cover, the motor rotates to drive the diaphragm to relax, and the water inlet valve plate and the water discharge valve plate are opened and closed, so that liquid is sucked from the water inlet hole and discharged from the water discharge hole; the middle transmission mechanism is provided with an assembly hole matched with the diaphragm, the lower end of the diaphragm penetrates through the assembly hole, and the middle part of the diaphragm is detachably connected with the assembly hole; the upper end of the diaphragm is connected above the base through a diaphragm bracket. The invention reduces the difficulty of disassembling and assembling the diaphragm pump and prolongs the service life of the whole diaphragm pump.

Description

One-way diaphragm pump

Technical Field

The invention relates to the technical field of water pumps, in particular to a one-way diaphragm pump.

Background

The diaphragm pump is widely applied, is common in household appliances, such as coffee machines, water dispensers, water purifiers, mops and the like, and tends to replace electromagnetic water pumps due to excellent performance. However, the existing diaphragm pump has poor forward leakage-proof capability, and when the forward leakage-proof requirement is high in some applications, the diaphragm pump needs to be matched with a one-way valve for use so as to meet the requirement of forward leakage-proof. The patent with publication number CN208564922U discloses a miniature diaphragm water pump, the action of a one-way valve is moved to the interior of the water pump, so that the structure of the water pump is properly increased, the space occupied by two components of the water pump and the one-way valve is greatly reduced, and the cost is also reduced.

However, the above patents still have disadvantages: the diaphragm and the valve plate of the diaphragm pump are both made of rubber, and theoretically, the service life of the rubber can be very long, and the service life times can reach 800-2000 ten thousand. However, in the actual use process, the diaphragm pump usually needs to be in a high-speed running state, and the service life of the diaphragm and the valve plate can be influenced by idling or half-empty installation. The life of the membrane itself is also shortened if the fluid contains a large amount of solid particles.

In the actual maintenance process, although the diaphragm and the valve plate of the diaphragm pump are obviously damaged, the whole diaphragm pump is still maintained by replacing the diaphragm pump, and obviously, the method wastes resources and cannot make the best use of the resources. The main reasons for replacing the whole diaphragm pump are: 1. the miniature diaphragm pump is small in size, the length of a diaphragm pump in a household appliance is 6-12cm, the size of each internal part is smaller, the difficulty in manually disassembling the pump body of the diaphragm pump is high, and the difficulty in assembling is high. 2. The diaphragm and the valve plate are installed at the core position of the pump body, the diaphragm and the valve plate can be replaced only after the whole pump body is completely disassembled, parts participating in the disassembling process are multiple, and even if a special tool is arranged, the parts are difficult to disassemble and assemble smoothly. Especially, the dislocation of internal parts is easily caused in the process of covering the end cover and screwing the bolt, and the installation can not be ensured to be in place. Therefore, the diaphragm pump is difficult to disassemble and assemble, the installation operation requirement is very fine, the problem of weak water pumping capacity caused by the condition that the assembly is not in place is solved, and the diaphragm and the valve plate are difficult to replace. Therefore, the actual maintenance mode is to replace the whole diaphragm pump, even the whole electric appliance, so as to reduce the labor cost of maintenance, but also cause resource waste.

Disclosure of Invention

The defects in the prior art are overcome, so that the difficulty in disassembling and assembling the diaphragm pump is reduced, and the service life of the whole diaphragm pump is prolonged. The invention provides a one-way diaphragm pump which comprises a motor and a pump body, wherein the motor is connected to the lower end of the pump body, and the pump body comprises a base, an intermediate transmission mechanism, a diaphragm, a water inlet valve plate, a water discharge valve plate and an end cover;

the diaphragm is arranged above the base through a diaphragm support and is in transmission connection with an output shaft of the motor through an intermediate transmission mechanism; the water inlet valve plate and the water discharge valve plate are respectively arranged at the water inlet hole and the water discharge hole of the end cover, the diaphragm is driven to relax by the rotation of the motor, the water inlet valve plate and the water discharge valve plate are opened and closed, and then liquid is sucked from the water inlet hole and discharged from the water discharge hole;

the middle transmission mechanism is provided with an assembly hole matched with the diaphragm, the lower end of the diaphragm penetrates through the assembly hole, and the middle part of the diaphragm is detachably connected with the assembly hole; the upper end of the diaphragm is connected above the base through a diaphragm bracket;

the end cover is provided with a detachable water inlet nozzle and a detachable water discharge nozzle; the water inlet hole is formed in the water inlet nozzle, and the water inlet valve piece is connected to the lower end of the water inlet nozzle and attached to the water inlet hole and used for preventing liquid from being discharged; the drain hole is arranged on the drain nozzle, and the drain valve piece is connected to the lower end of the drain nozzle and attached to the drain hole and used for preventing liquid from being sucked; the water inlet nozzle and the water discharging nozzle are respectively connected to the mounting groove in the upper end of the end cover, the diaphragm support is tightly pressed through the water inlet nozzle and the water discharging nozzle, and a sealed overflowing inner cavity is formed among the water inlet valve plate, the diaphragm and the water discharging valve plate.

The invention has the beneficial effects that:

the diaphragm, the valve block of intaking and the drain valve piece of intaking, arbitrary one of these three appears damaging, and the pumping pressure all can drop or the leak protection effect weakens, in case this kind of problem appears, only need dismantle intake nozzle and drainage nozzle limit can change diaphragm, water intaking valve piece and drain valve piece, has avoided dismantling whole pump body, has reduced the maintenance step of changing diaphragm, intaking valve block and drain valve piece and bringing to greatly reduced the maintenance degree of difficulty, be favorable to prolonging the life of whole diaphragm pump.

Preferably, the diaphragm support is provided with an opening for the diaphragm to pass through, the upper end of the diaphragm is provided with a gasket extending towards the horizontal direction, and the gasket is pressed on the diaphragm support through the water inlet nozzle and the water discharge nozzle.

Preferably, a valve plate support used for supporting the drain valve plate is arranged on the gasket, part of the valve plate support located right below the drain valve plate can be detached, and the rest of the valve plate support is fixedly connected between the end cover and the membrane support. After the drainage nozzle is disassembled, the drainage valve plate and the detachable part of the valve plate bracket can be sequentially disassembled, so that the drainage valve plate can be quickly replaced. The water inlet nozzle is continuously detached, so that the gasket of the whole diaphragm loses positive pressure, and the diaphragm can be taken out for replacement. The water inlet nozzle after being disassembled can replace the water inlet valve sheet independently, so that the replacement of the membrane, the water inlet valve sheet and the drain valve sheet is very convenient.

Preferably, the lower surface of the drainage valve plate is provided with a first groove, the upper surface of the drainage valve plate is provided with a first bulge, the detachable part of the valve plate support is provided with a second bulge opposite to the first groove, the drainage nozzle is provided with a second groove corresponding to the first bulge, the second bulge is tightly propped in the first groove and the first bulge is tightly propped in the second groove, and the drainage valve plate is further clamped between the drainage nozzle and the detachable part of the valve plate. The upper surface and the lower surface of the drain valve plate are both limited, and the whole drain valve is firmly fixed and is not easy to loosen after being installed.

Preferably, the drain hole is provided with an elastic plug therein for preventing liquid from flowing into the drain hole from the outside. The water inlet valve plate and the water discharge valve plate are used as a first pass of conventional unidirectional flow, and the elastic plug is used as a second pass of unidirectional flow, so that the forward leakage-proof capability is improved.

Preferably, the lower surface of the water inlet nozzle is provided with a vertical mounting hole, the upper surface of the water inlet valve plate is provided with a fixing shaft matched with the mounting hole, and the fixing shaft is inserted into the mounting hole so that the water inlet valve plate is connected to the lower end of the water inlet nozzle.

Preferably, the outer surface of the fixed shaft is provided with a plurality of positioning rings, and all the positioning rings are distributed at equal intervals along the axial direction of the fixed shaft; and annular positioning grooves which correspond to all the positioning rings one to one are arranged in the mounting holes. A plurality of holding rings and a plurality of cyclic annular constant head tank one-to-one for the fixed of valve block of intaking is very firm, and only after the fixed axle totally inserted mounting hole, all holding rings just can block into in all cyclic annular constant head tanks, have played the effect of installation location simultaneously.

Preferably, the vertical lateral wall of intake nozzle and the vertical lateral wall of water drainage nozzle all are equipped with vertical spacing, every the lateral wall of mounting groove all is equipped with and corresponds the spout of spacing adaptation.

Preferably, a baffle plate for clamping the water inlet nozzle and the water discharge nozzle is arranged on the end cover, and the baffle plate is fixed with the end cover through screws. The spacing strip of inlet tap is vertical along the spout in one of them mounting groove and inserts, and the spacing strip of drain tap is vertical along the spout in the other mounting groove, then covers the baffle, screws up the screw, and inlet tap and drain tap installation are accomplished. Otherwise, the screw is disassembled, the water inlet nozzle and the water discharging nozzle are taken out from the corresponding mounting grooves, and the disassembling and assembling process is convenient and quick.

Preferably, the end cover, the fixed valve plate support and the membrane support are sequentially fixed on the base through bolts. The water inlet valve plate is connected with the water inlet nozzle to form one part set, the drainage valve plate is connected with the drainage nozzle to form another part set, and the diaphragm, the water inlet valve plate and the drainage valve plate can be replaced by disassembling the two part sets. The end cover, the fixed valve plate support and the membrane support are not directly associated with the membrane, the water inlet valve plate and the drain valve plate, and the splitting process of the membrane, the water inlet valve plate and the drain valve plate is not involved, so that the end cover, the fixed valve plate support and the membrane are fixed on the base for a long time, a part which is not easy to damage is formed, and the process of dismounting and mounting is avoided.

Drawings

In order to more clearly illustrate the detailed description of the invention or the technical solutions in the prior art, the drawings that are needed in the detailed description of the invention or the prior art will be briefly described below. Throughout the drawings, like elements or portions are generally identified by like reference numerals. In the drawings, elements or portions are not necessarily drawn to scale.

FIG. 1 is a schematic structural diagram of the present embodiment;

FIG. 2 is a top view of FIG. 1;

FIG. 3 is an enlarged view of FIG. 1 at A;

FIG. 4 is an enlarged view at B of FIG. 1;

fig. 5 is an exploded view of fig. 1.

In the attached drawing, a motor 1, a pump body 2, a base 3, an intermediate transmission mechanism 4, a diaphragm 5, a water inlet valve sheet 6, a water outlet valve sheet 7, an end cover 8, a diaphragm support 9, an assembly hole 10, a water inlet nozzle 11, a water outlet nozzle 12, an installation groove 13, a limiting strip 14, a baffle plate 15, a bolt 16, an elastic plug 17, an opening 18, a gasket 19, a valve sheet support 20, a first groove 21, a second groove 22, a first bulge 23, a second bulge 24, an installation hole 25, a fixed shaft 26, a positioning ring 27, an annular positioning groove 28, a screw 29 and a sliding groove 30.

Detailed Description

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and therefore are only examples, and the protection scope of the present invention is not limited thereby.

It is to be noted that, unless otherwise specified, technical or scientific terms used herein shall have the ordinary meaning as understood by those skilled in the art to which the invention pertains.

As shown in fig. 1, the embodiment provides a one-way diaphragm pump, which includes a motor 1 and a pump body 2, where the motor 1 is connected to the lower end of the pump body 2, and the pump body 2 includes a base 3, an intermediate transmission mechanism 4, a diaphragm 5, a water inlet valve 6, a water outlet valve 7, and an end cover 8. The diaphragm 5 is arranged above the base 3 through a diaphragm bracket 9, and the diaphragm 5 is in transmission connection with an output shaft of the motor 1 through an intermediate transmission mechanism 4; the water inlet valve plate 6 and the water discharge valve plate 7 are respectively arranged at a water inlet and a water discharge hole of the end cover 8, the diaphragm 5 is driven to relax by the rotation of the motor 1, the water inlet valve plate 6 and the water discharge valve plate 7 are opened and closed, and then liquid is sucked from the water inlet and discharged from the water discharge hole; middle drive mechanism 4 is equipped with the pilot hole 10 with diaphragm 5 adaptation, the lower extreme of diaphragm 5 pass pilot hole 10 and the middle part of diaphragm 5 with pilot hole 10 but split joint. The upper end of the diaphragm 5 is connected above the base 3 through a diaphragm bracket 9. In order to replace the diaphragm 5, the water inlet valve 6 and the water outlet valve 7 conveniently, reduce the maintenance difficulty and prolong the service life of the whole diaphragm pump, the structure of the pump body 2 is improved as follows:

as shown in fig. 2 to 5, the end cover 8 is provided with a detachable water inlet nozzle 11 and a detachable water outlet nozzle 12, that is, the water inlet nozzle 11 and the water outlet nozzle 12 are not integrated with the end cover 8, and the water inlet nozzle 11 and the water outlet nozzle 12 are connected with the end cover 8 in the following manner: the water inlet nozzle 11 and the water discharging nozzle 12 are connected to the mounting grooves 13 in the upper end of the end cover 8 respectively, the mounting grooves 13 are two, and the two mounting grooves 13 correspond to the water inlet nozzle 11 and the water discharging nozzle 12 one to one respectively. Further, the vertical lateral wall of intake nozzle 11 and the vertical lateral wall of water discharging nozzle 12 all are equipped with vertical spacing 14, every the lateral wall of mounting groove 13 all is equipped with and corresponds the spout of spacing 14 adaptations. The upper surface of the end cover 8 is provided with a baffle plate 15 used for clamping the water inlet nozzle 11 and the water discharge nozzle 12, and the baffle plate 15 is fixed with the end cover 8 through a screw 29. The stopper 14 of the inlet nozzle 11 is vertically inserted along the slide groove in one of the mounting grooves 13, and the stopper 14 of the discharge nozzle 12 is vertically inserted along the slide groove in the other mounting groove 13, and then the baffle 15 is covered, the screw 29 is tightened, and the inlet nozzle 11 and the discharge nozzle 12 are completely installed. On the contrary, the screw 29 is disassembled, the water inlet nozzle 11 and the water discharging nozzle 12 are taken out from the corresponding mounting groove 13, and the dismounting process is convenient and quick.

In this embodiment, the water inlet is arranged on the water inlet nozzle 11, and the water inlet valve plate 6 is connected to the lower end of the water inlet nozzle 11 and attached to the water inlet to prevent liquid from being discharged; the drain hole is arranged on the drain nozzle 12, and the drain valve plate 7 is connected to the lower end of the drain nozzle 12 and attached to the drain hole to prevent liquid from being sucked. The membrane support 9 is pressed tightly through the water inlet nozzle 11 and the water discharge nozzle 12, and a sealed overflowing inner cavity is formed among the water inlet valve 6, the membrane 5 and the water discharge valve 7. The motor 1 drives the middle transmission mechanism 4 to enable the diaphragm 5 to relax, specifically, the diaphragm 5 expands to generate suction force, liquid is sucked from the water inlet hole, the water inlet valve plate 6 is pushed open in the process, and the liquid enters the overflowing inner cavity. The diaphragm 5 is compressed, the dynamic liquid is squeezed into the drain hole from the overflowing inner cavity, the drain valve plate 7 in the middle is pushed open, and the water inlet valve plate 6 is closed. The drain hole is provided with an elastic plug 17 for preventing liquid from flowing into the drain hole from the outside. In the whole water pumping process, the water inlet valve sheet 6 and the water outlet valve sheet 7 are used as a first pass of conventional unidirectional flow, and the elastic plug 17 is used as a second pass of unidirectional flow, so that the forward leakage-proof capability is improved.

As shown in fig. 1 and 5, the specific fixing modes of the diaphragm 5, the water inlet valve 6 and the water outlet valve 7 are as follows: the diaphragm support 9 is provided with an opening 18 for the diaphragm 5 to pass through, the upper end of the diaphragm 5 is provided with a gasket 19 extending towards the horizontal direction, and the gasket 19 is pressed on the diaphragm support 9 through the water inlet nozzle 11 and the water discharge nozzle 12. The gasket 19 is provided with a valve plate support 20 for supporting the drain valve plate 7, a part of the valve plate support 20 positioned under the drain valve plate 7 can be detached, and the rest of the valve plate support 20 is fixedly connected between the end cover 8 and the membrane support 9. After the drain nozzle 12 is disassembled, the drain valve plate 7 and the detachable part of the valve plate bracket 20 can be sequentially disassembled, so that the drain valve plate 7 can be rapidly replaced. The water inlet nozzle 11 is continuously detached, so that the gasket 19 of the whole diaphragm 5 loses positive pressure, and the diaphragm 5 can be taken out for replacement. The water inlet nozzle 11 after being disassembled can replace the water inlet valve sheet 6 independently, so that the membrane 5, the water inlet valve sheet 6 and the drain valve sheet 7 can be replaced very conveniently. Further, the lower surface of drain valve plate 7 is provided with a first groove 21, the upper surface of drain valve plate 7 is provided with a first protrusion 23, detachable part of valve plate support 20 is provided with a second protrusion 24 opposite to first groove 21, drain nozzle 12 is provided with a second groove 22 corresponding to first protrusion 23, and the second protrusion 24 is tightly pressed in first groove 21 and first protrusion 23 is tightly pressed in second groove 22, so that drain valve plate 7 is tightly pressed between drain nozzle 12 and detachable part of valve plate. The upper surface and the lower surface of the drain valve plate 7 are both limited, and the whole drain valve is firmly fixed and is not easy to loosen after the drain valve is installed. Still further, the lower surface of the water inlet nozzle 11 is provided with a vertical mounting hole 25, the upper surface of the water inlet valve plate 6 is provided with a fixing shaft 26 matched with the mounting hole 25, and the fixing shaft 26 is inserted into the mounting hole 25, so that the water inlet valve plate 6 is connected to the lower end of the water inlet nozzle 11. A plurality of positioning rings 27 are arranged on the outer surface of the fixed shaft 26, and all the positioning rings 27 are distributed at equal intervals along the axial direction of the fixed shaft 26; the mounting hole 25 is provided with annular positioning grooves 28 corresponding to all the positioning rings 27 one by one. The positioning rings 27 correspond to the annular positioning grooves 28 one by one, so that the water inlet valve plate 6 is fixed very stably, and only after the fixing shaft 26 is inserted into the mounting hole 25 completely, all the positioning rings 27 can be clamped into all the annular positioning grooves 28, and the mounting and positioning effects are achieved.

In order to reduce unnecessary parts in the assembling and disassembling process, in the embodiment, the end cover 8, the fixed valve sheet bracket 20 and the diaphragm bracket 9 are sequentially fixed on the base 3 through the bolts 16. The water inlet valve plate 6 is connected with the water inlet nozzle 11 to form one part set, the drain valve plate 7 is connected with the drain nozzle 12 to form another part set, and the diaphragm 5, the water inlet valve plate 6 and the drain valve plate 7 can be replaced by disassembling the two part sets. The end cover 8, the fixed valve plate support 20 and the membrane support 9 are not directly related to the membrane 5, the water inlet valve plate 6 and the water outlet valve plate 7, and the disassembling process of the membrane 5, the water inlet valve plate 6 and the water outlet valve plate 7 is not involved, so that the end cover 8, the fixed valve plate support 20 and the membrane 5 are fixed on the base 3 for a long time, a part which is not easy to damage is formed, and the process of disassembling and assembling is avoided. Any one of the diaphragm 5, the water inlet valve sheet 6 and the water discharge valve sheet 7 is damaged, the pump pressure can be reduced or the leakage-proof effect is weakened, once the problem occurs, the diaphragm 5, the water inlet valve sheet 6 and the water discharge valve sheet 7 can be replaced only by detaching the water inlet nozzle 11 and the water discharge nozzle 12, the whole pump body 2 is prevented from being detached, maintenance steps caused by replacing the diaphragm 5, the water inlet valve sheet 6 and the water discharge valve sheet 7 are reduced, the maintenance difficulty is greatly reduced, and the service life of the whole diaphragm pump is prolonged.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present invention, and they should be construed as being included in the following claims and description.

Claims

1. A one-way diaphragm pump comprises a motor and a pump body, wherein the motor is connected to the lower end of the pump body, and the pump body comprises a base, an intermediate transmission mechanism, a diaphragm, a water inlet valve plate, a water discharge valve plate and an end cover;

the method is characterized in that: the middle transmission mechanism is provided with an assembly hole matched with the diaphragm, the lower end of the diaphragm penetrates through the assembly hole, and the middle part of the diaphragm is detachably connected with the assembly hole; the upper end of the diaphragm is connected above the base through a diaphragm bracket;

the diaphragm support is provided with an opening for the diaphragm to pass through, the upper end of the diaphragm is provided with a gasket extending in the horizontal direction, and the gasket is tightly pressed on the diaphragm support through a water inlet nozzle and a water discharge nozzle; a valve plate bracket used for propping against the drainage valve plate is arranged on the gasket, part of the valve plate bracket positioned right below the drainage valve plate can be detached, and the rest of the valve plate bracket is fixedly connected between the end cover and the membrane bracket; the lower surface of the drainage valve plate is provided with a first groove, the upper surface of the drainage valve plate is provided with a first bulge, the detachable part of the valve plate support is provided with a second bulge opposite to the first groove, the drainage nozzle is provided with a second groove corresponding to the first bulge, the drainage nozzle is tightly propped in the first groove through the second bulge and the second groove through the first bulge, and then the drainage valve plate is tightly clamped between the drainage nozzle and the detachable part of the valve plate;

the end cover is provided with a detachable water inlet nozzle and a detachable water discharge nozzle; the water inlet hole is formed in the water inlet nozzle, and the water inlet valve piece is connected to the lower end of the water inlet nozzle and attached to the water inlet hole and used for preventing liquid from being discharged; the drain hole is arranged on the drain nozzle, and the drain valve sheet is connected to the lower end of the drain nozzle and attached to the drain hole and used for preventing liquid from being sucked; the water inlet nozzle and the water discharging nozzle are respectively connected to the mounting groove in the upper end of the end cover, the diaphragm support is tightly pressed through the water inlet nozzle and the water discharging nozzle, and a sealed overflowing inner cavity is formed among the water inlet valve plate, the diaphragm and the water discharging valve plate.

2. A one-way diaphragm pump according to claim 1, wherein: the drain hole is internally provided with an elastic plug for preventing liquid from flowing into the drain hole from the outside.

3. A one-way diaphragm pump according to claim 1, wherein: the lower surface of the water inlet nozzle is provided with a vertical mounting hole, the upper surface of the water inlet valve plate is provided with a fixing shaft matched with the mounting hole, and the fixing shaft is inserted into the mounting hole so that the water inlet valve plate is connected to the lower end of the water inlet nozzle.

4. A one-way diaphragm pump according to claim 3, wherein: a plurality of positioning rings are arranged on the outer surface of the fixed shaft, and all the positioning rings are distributed at equal intervals along the axial direction of the fixed shaft; and annular positioning grooves which correspond to all the positioning rings one to one are arranged in the mounting holes.

5. A one-way diaphragm pump according to claim 1, wherein: the vertical lateral wall of intake nozzle and the vertical lateral wall of water drainage nozzle all are equipped with vertical spacing, every the lateral wall of mounting groove all is equipped with and corresponds the spout of spacing adaptation.

6. A one way diaphragm pump according to claim 5, wherein: the water inlet device is characterized in that a baffle used for clamping the water inlet nozzle and the water discharge nozzle is arranged on the end cover, and the baffle is fixed with the end cover through screws.

7. A one-way diaphragm pump according to claim 6, wherein: the end cover, the fixed valve plate support and the diaphragm support are sequentially fixed on the base through bolts.