Lock mechanism

Abstract

To provide a lock mechanism used for a drain plug device and having a simpler structure.SOLUTION: The lock mechanism 57 has a turning part 53 turning around a turning shaft R1 by reciprocation of the operated part 7, and a transmission end part 54a provided at an end of the transmission part 54 and regulated to reciprocate in a linear direction, and the turning part 53 has a projection part 53b capable of reciprocating along an arc-shaped path. When the discharge port is in the open state, the projection portion 53b is disposed at the top dead point position or a position in the vicinity of the top dead point position, which is a position where the center of the projection portion R1 overlaps with an imaginary surface 54a including the rotation shaft V1 and parallel to the reciprocating direction of the transmission terminal portion center, so that even if a force in the backward direction is applied to the plug lid when the discharge port is in the open state, the rotation of the rotation portion 53 is restricted, and the transmission portion 54 can be locked in a state of being moved forward.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a locking mechanism for keeping a drain outlet of a tank body in an open state. [Background technology]

[0002] BACKGROUND ART Conventionally, drain plug devices are known for switching between open and closed states of a drain outlet formed in a tank body (for example, a bathtub or a washbasin).

[0003] A drain plug device includes a plug cover that is provided on a drain outlet, a support shaft that supports the plug cover and is capable of reciprocating (moving up and down), a reciprocating operated part (such as an operation button), and a reciprocating transmission part (such as a wire) that transmits the driving force generated by operating the operated part from the operated part to the plug cover. In such a drain plug device, operation of the operated part causes the transmission part to move back and forth, and as a result, the support shaft and plug cover move up and down, switching the open / closed state of the drain outlet.

[0004] It is also conceivable to provide a locking mechanism for maintaining the drain outlet in an open position in correspondence with the drain plug device (see, for example, Patent Document 1). By locking the transmission part in a forward-moving position using the locking mechanism, it becomes possible to maintain the drain outlet in an open position even if a force in the backward-moving direction is applied to the plug cover when the drain outlet is open, such as by stepping on the plug cover or placing a heavy object on the plug cover. An example of a locking mechanism is a thrust lock mechanism. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2023-65733 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the above-described thrust lock mechanism has a relatively complicated structure, and therefore, from the standpoints of productivity and cost, a lock mechanism with a simpler structure is sometimes desired.

[0007] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a locking mechanism with a simpler structure. [Means for solving the problem]

[0008] The following describes each of the means suitable for achieving the above object, with specific effects of the corresponding means added as necessary.

[0009] Means 1. A drain plug device having a plug lid for opening and closing the drain outlet of a tank body, an operated part that can move back and forth, and a transmission part that can move back and forth in accordance with the reciprocating movement of the operated part and transmits the driving force caused by the movement of the operated part to the plug lid side, and the forward movement of the operated part causes the transmission part to move forward, thereby moving the plug lid forward and opening the drain outlet, while the return movement of the operated part causes the transmission part to move backward, thereby moving the plug lid backward and closing the drain outlet, A locking mechanism for maintaining the drain outlet in an open state by locking the transmission part in a forward movement state, a rotating part that rotates about a predetermined rotation axis as the operated part moves back and forth; a transmission end portion provided at an end of the transmission portion and restricted to reciprocating in a linear direction; the rotating portion has a protrusion that can reciprocate along an arc-shaped path centered on the rotation axis when the rotating portion rotates, The transmission end portion has a protrusion contact surface that is pressed against the protrusion portion when the protrusion portion moves forward along an arc-shaped path to switch the drain outlet from a closed state to an open state, and is configured to allow sliding movement of the protrusion portion along a direction perpendicular to the reciprocating movement direction of the transmission end portion, When the drain outlet is in an open state and a force in the backward direction is applied to the plug cover, the force in the backward direction is applied to the transmission end portion, When the drain outlet is in the open state, the protrusion is positioned at or near the top dead center position, where its center overlaps with an imaginary plane that includes the pivot axis and is parallel to the direction of reciprocating movement of the transmission end part, so that even if a force in the reciprocating direction is applied to the plug cover when the drain outlet is in the open state, the locking mechanism is configured to restrict the rotation of the pivot part and lock the transmission part in a forward moving position.

[0010] According to the above-mentioned means 1, by positioning the protrusion provided on the rotating part at or near the top dead center position, when the drain outlet is in the open state, a force in the backward direction is applied to the plug cover, and even if a force in the backward direction is applied to the transmission end part, the transmission part can be locked in the forward moving position. Therefore, the structure of the locking mechanism can be simplified, which is advantageous in terms of productivity and cost. Furthermore, the locking mechanism can prevent the user from switching between the open and closed states unintentionally, thereby improving usability for the user.

[0011] As a more specific method for locking the transmission section, for example, each of the methods 2 to 4 described below can be adopted.

[0012] Means 2. The locking mechanism described in Means 1 is characterized in that when the drain outlet is in the open state, the protrusion is positioned just before the top dead center position and in the vicinity of the top dead center position, and by utilizing the frictional force generated by contact between the protrusion and the protrusion contact surface in a direction that restricts the sliding movement of the protrusion, even if a force in the backward direction is applied to the plug cover when the drain outlet is in the open state, the rotation of the rotating part is restricted and the transmission part can be locked in a forward moving position.

[0013] According to the above-mentioned means 2, the forward movement amount of the protrusion (the rotation amount of the rotation part) when locking the transmission part can be made relatively small, thereby improving operability.

[0014] Means 3. A locking mechanism as described in Means 1, characterized in that when the drain outlet is in the open state, the protrusion is positioned at the top dead center position, thereby restricting the rotation of the rotating part and locking the transmission part in a forward moving state even if a force in the backward moving direction is applied to the plug cover when the drain outlet is in the open state.

[0015] According to the above-mentioned means 3, when the drain outlet is in the open state, the protrusion is positioned at the top dead center position, so the rotating part does not rotate even if a force in the backward direction is applied to the transmission end part. This makes it possible to more reliably maintain the transmission part in the locked state, and ultimately to more reliably maintain the drain outlet in the open state.

[0016] Means 4. The rotating portion is configured such that further rotation is restricted when the protrusion moves forward to a position beyond the top dead center position, The locking mechanism described in means 1 is characterized in that when the drain outlet is in the open state, the protrusion is positioned at a position beyond the top dead center position, so that even if a force in the backward direction is applied to the plug cover when the drain outlet is in the open state, the rotation of the rotating part is restricted and the transmission part can be locked in a forward moving position.

[0017] According to the above-mentioned means 4, the rotating part is configured so that further rotation is restricted when the protrusion moves forward to a position beyond the top dead center position. Furthermore, when the drain outlet is in the open state, the protrusion is positioned at a position beyond the top dead center position, so the rotating part will not rotate even if a force in the backward direction is applied to the transmission end part. This makes it possible to more reliably maintain the transmission part in the locked state, and ultimately to more reliably maintain the drain outlet in the open state.

[0018] Furthermore, according to the above-mentioned means 4, even if there is a slight difference in the position of the protrusion when the drain outlet is in the open state (for example, even if the protrusion is positioned slightly forward from the target position in the design), the transmission part can be locked more reliably, thereby further improving the operational stability of the device.

[0019] Means 5. A locking mechanism as described in Means 1, characterized in that it is provided with a spring portion that assists in locking the transmission portion by applying a force to the rotating portion in a direction that inhibits the return movement of the protrusion portion when the drain outlet is in an open state.

[0020] According to the above-mentioned means 5, by using the spring portion, the transmission portion can be more reliably maintained in the locked state, and consequently the drain outlet can be more reliably maintained in the open state.

[0021] Means 6. The transmission end portion has a return-motion protrusion contact surface that is pressed against the protrusion when the protrusion returns along a circular arc path to switch the drain outlet from an open state to a closed state; The locking mechanism described in means 5 is characterized in that it has a force reversal mechanism that can reverse the direction of the force applied from the spring part to the rotating part during the return movement of the protrusion part.

[0022] According to the above-mentioned means 6, the force reversal mechanism reverses the direction of the force applied from the spring to the rotating part during the return movement of the protrusion, from a force that would hinder the return movement of the protrusion or transmission end part to a force that promotes the return movement of the protrusion or transmission end part. Therefore, when operating the operated part to switch the open / closed state of the drain outlet, the force applied from the spring part can be used as an assist force to help with the switch. This further improves the operability of switching the open / closed state of the drain outlet.

[0023] Means 7. The force reversal mechanism is a first end portion rotatably supported about a first end rotation axis parallel to the rotation axis; the other end portion is attached to the rotating part or an intermediate rotating part that is rotatable about an axis parallel to the rotating shaft and that is configured so that the driving force due to the rotation of the intermediate rotating part is transmitted to the rotating part, and the other end portion is attached to the intermediate rotating part in a state that the other end portion is rotatable about an axis parallel to the rotating shaft; The other end portion moves along an arcuate path when the rotating portion or the intervening rotating portion to which the other end portion is attached rotates, and the spring portion is disposed in a compressed state between the one end portion and the other end portion, The locking mechanism described in means 6 is characterized in that, during the return movement of the protrusion, the other end side rotation axis crosses a second imaginary plane that includes the one end side rotation axis and the rotation center of the rotation part or the intervening rotation part to which the other end side portion is attached, thereby reversing the direction of the force applied from the spring part to the rotation part.

[0024] According to the above-mentioned means 7, the applied force reversal mechanism can be realized with a relatively simple configuration, which can more reliably prevent the structure from becoming complicated and suppress an increase in costs.

[0025] Furthermore, since the spring portion is provided in a compressed state, the device can be made smaller than when the spring portion is provided in a natural length state or an extended state.

[0026] Means 8. The locking mechanism described in Means 1, wherein the drain plug device has a shock absorber means that can absorb the load applied to the transmission part by compressively deforming when a force in the reciprocating direction is applied to the plug cover when the drain outlet is in the open state.

[0027] According to the above-mentioned means 8, even if a relatively large force is applied to the plug cap in the backward direction, the shock absorber means can more reliably prevent deformation or damage to the transmission part, protrusions, etc. Therefore, the operational stability and life of the device can be improved.

[0028] The technical features relating to the above-mentioned means may be combined as appropriate. For example, one of the technical features relating to the above-mentioned means 2 to 4 may be combined with at least one of the technical features relating to the above-mentioned means 5 to 8. [Brief explanation of the drawings]

[0029] [Figure 1] 1 is a partially cutaway perspective view showing the general configuration of the bathroom unit, drain plug device, etc. when the drain outlet is in a closed state. FIG. [Figure 2] FIG. 2 is a cross-sectional schematic view of the drain outlet device. [Figure 3] FIG. 10 is a schematic perspective view of the operating device when the drain outlet is in a closed state. [Figure 4] FIG. 10 is a schematic side view of the operating device when the drain outlet is in a closed state. [Figure 5] 1 is a partially cutaway perspective view showing the general configuration of a bathroom unit, a drain plug device, and the like when the drain outlet is in an open state. FIG. [Figure 6] FIG. 10 is a schematic perspective view of the operating device when the drain outlet is in an open state. [Figure 7] FIG. 10 is a schematic side view of the operating device when the drain outlet is in an open state. [Figure 8] FIG. 2 is a schematic perspective view showing a cover and other components that constitute a part of the operating device. [Figure 9] FIG. 10 is a schematic perspective view of an operating device in another embodiment, configured so that a protrusion is positioned at a position beyond the top dead center position when the drain outlet is in an open state. [Figure 10] FIG. 10 is a schematic side view of an operating device in another embodiment, configured so that a protrusion is positioned beyond the top dead center position when the drain outlet is in an open state. [Figure 11] FIG. 10 is a schematic side view of an operating device in another embodiment, configured so that a protrusion is positioned in a position near and in front of the top dead center position when the drain outlet is in an open state. DETAILED DESCRIPTION OF THE INVENTION

[0030] One embodiment will be described below with reference to the drawings. Fig. 1 shows the schematic configuration of a bathroom unit 100 that constitutes a bathroom, a bathtub 110 as a "tub body" disposed within the bathroom unit 100 (i.e., the bathroom), and a drain plug device 1 provided for the bathtub 110. The bathtub 110 has a bottom wall 111 (see Fig. 2) that constitutes the bottom surface and a side wall 112 that stands on the outer periphery of the bottom wall 111, with a drain port 113 (see Fig. 2) penetrating the bottom wall 111. The side wall 112 of the bathtub 110 that faces the washing area 101 of the bathroom is covered with a plate-shaped apron 120, and a mounting hole 121 (see Fig. 4) is penetrating the apron 120.

[0031] The drain plug device 1 includes an operating device 2 and a drain outlet device 9. First, the general configuration of the drain outlet device 9 will be described, and then the operating device 2 will be described.

[0032] The drain outlet device 9 is provided corresponding to the drain outlet 113, and includes a drain outlet member 91, an attachment member 92, a support shaft mechanism 93, and a plug lid 94, as shown in FIG.

[0033] The drain outlet member 91 is formed in a cylindrical shape and has protrusions and notches on its inner periphery that are used to attach the attachment member 92. The drain outlet member 91 is inserted into the drain outlet 113 so that its central axis approximately coincides with the central axis of the drain outlet 113. More specifically, the drain outlet member 91 is inserted into the drain outlet 113 by threading a pipe (not shown) into a male thread formed on its outer periphery, and by sandwiching the bottom wall portion 111 between a flange formed on its upper end and the pipe. In this embodiment, an annular seal member 95 made of an elastically deformable material (e.g., rubber, resin, etc.) is disposed between the flange and the bottom wall portion 111, and the seal member 95 ensures watertightness between the drain outlet member 91 and the bottom wall portion 111.

[0034] The attachment member 92 is for holding the support shaft mechanism 93 inside the drain outlet member 91, i.e., in the drainage flow path. The attachment member 92 includes an outer cylindrical portion 92a and an inner cylindrical portion 92b formed concentrically, and an arm portion 92c connecting these. The attachment member 92 holds the support shaft mechanism 93 on the inner periphery of the inner cylindrical portion 92b, while the outer cylindrical portion 92a is attached to the drain outlet member 91 using the protrusions and notches, thereby holding the support shaft mechanism 93 inside (inside) the drain outlet member 91.

[0035] The support shaft mechanism 93 is a mechanism for moving the plug lid 94 up and down. The support shaft mechanism 93 includes a cylindrical case 93a that is held by the inner cylindrical portion 92b so that it cannot move up and down, a support shaft 93b that is arranged inside the cylindrical case 93a and can move up and down, and a return spring 93c that is arranged between the cylindrical case 93a and the support shaft 93b and applies a force to the support shaft 93b in a downward direction as it moves back (downward). The force applied by the return spring 93c to the support shaft 93b can be transmitted to a transmission end portion 54a, also described below, via an inner wire 54b, etc., which will be described below.

[0036] The support shaft 93b has a plug lid 94 attached to its upper end, and can be pushed up by an inner wire 54b that moves forward (moves from the operating device 2 side to the drain outlet device 9 side). An absorber spring 93d is provided inside the support shaft 93b as a "shock absorber means." When the drain outlet 113 is in the open state, if a large force is applied to the plug lid 94 in the backward (downward) direction by, for example, stepping on the plug lid 94, the absorber spring 93d is compressed and deformed, thereby absorbing the load applied to the transmission unit 54 (particularly the inner wire 54b) and the attachment member 92, which will be described later. When the drain outlet 113 is in the open state and a force is applied to the plug lid 94 in the backward (downward) direction, the force is applied to the transmission end unit 54a, which will be described later, via the inner wire 54b.

[0037] The plug lid 94 is a lid that opens and closes the drain outlet 113 by reciprocating (up and down) together with the support shaft 93b. The plug lid 94 comprises a disk-shaped plug lid main body 94a made of resin or the like, and a packing part 94b that is formed into an annular shape from an elastically deformable material (e.g., rubber, resin, etc.) and attached to the plug lid main body 94a. As the plug lid 94 reciprocates (up and down), the entire outer periphery of the packing part 94b comes into contact with or separates from the drain outlet member 91, thereby switching the open / closed state of the drain outlet 113.

[0038] Next, we will explain the operating device 2. The operating device 2 is used to open and close the drain outlet 113 by remotely operating the plug lid 94. As shown in Figures 3 and 4, the operating device 2 includes a case member 4, a transmitter 5, a biasing force imparting part 6, and an operated part 7.

[0039] The case member 4 is a portion that holds the biasing force imparting portion 6, the operated portion 7, etc., and also functions as a portion for attaching the operating device 2 to the apron 120. The case member 4 includes a flange member 41 and a box member .

[0040] The flange member 41 is inserted into the mounting hole 121 and has an overall rectangular cylindrical shape. The flange member 41 includes a cylindrical main body 41a that extends substantially horizontally, and a flange 41b that protrudes outward from one end of the main body 41a (the end on the washing area 101 side).

[0041] Furthermore, one end opening of the flange member 41 (main body 41a) is an opening 41c that opens to the washing area 101 side. In this embodiment, the opening 41c has a vertically long rectangular shape (i.e., the vertical length is greater than the horizontal length) when viewed from the front (when viewed from the washing area 101 side). The opening 41c may be a horizontally long rectangular shape, or may have a shape other than a rectangle (for example, a circular shape or a trapezoidal shape).

[0042] The flange member 41 also has an end face 41d located on the washing area 101 side. The end face 41d corresponds to the end face of the case member 4. The end face 41d is a portion extending from one end of the inner circumferential surface of the flange member 41 to the outer circumferential edge of the flange portion 41b, and in this embodiment, it protrudes slightly from the surface of the apron 120. Note that the end face 41d may be configured not to protrude from the surface of the apron 120 (for example, to be substantially flush with the surface of the apron 120) by, for example, arranging the end face 41d in a recess provided in the apron 120. In this case, it is possible to improve the appearance, safety, and ease of use.

[0043] Additionally, flange member 41 has a columnar shaft (not shown) extending horizontally at a position corresponding to the upper side of opening 41c. This shaft is used to rotatably attach operated part 7 to case member 4, and constitutes the rotation center of operated part 7.

[0044] The box member 42 has a rectangular cylindrical shape that is slightly larger than the main body 41a and has a closed end (other end) located on the opposite side from the flange member 41 (opposite side from the washing area 101). In this embodiment, the flange member 41 (main body 41a) is inserted into the box member 42 through the mounting hole 121, and the apron 120 is sandwiched between the flange 41b and one end face of the box member 42, and the flange member 41 and the box member 42 are fixed with screws, whereby the case member 4 is attached to the apron 120.

[0045] An elastically deformable annular seal member 8 is provided between one end face of the box member 42 and the apron 120. The seal member 8 prevents water leakage from between the apron 120 and the case member 4.

[0046] Furthermore, a housing mounting portion 42a is provided on the side surface of the box member 42. The housing mounting portion 42a forms a housing space for the biasing force imparting portion 6 and a rotating portion 53 (described later) of the transmission body 5, and is for mounting one end of a tube member 54f (described later). The housing mounting portion 42a is generally formed of a rectangular protrusion that protrudes laterally, and the internal space defined by the protrusion forms a space for housing the biasing force imparting portion 6, the rotating portion 53, and the like. Furthermore, a part of the protrusion forms a tube mounting portion 42b for holding one end of the tube member 54f.

[0047] In addition, a communication hole (not shown) that connects the internal space of the box member 42 with the internal space of the housing mounting portion 42a is provided at a predetermined position on the side surface of the box member 42. An intervening rotation portion 52, which will be described later, is inserted into the communication hole.

[0048] A cover 43 is provided to cover the side opening of the housing mounting portion 42a (see FIG. 8; FIG. 3 and other figures show a state in which the cover 43 is removed). The cover 43 is attached to the housing mounting portion 42a by, for example, screwing. The cover 43 holds the biasing force imparting portion 6, one end of a tube member 54f (described later), the transmission end portion 54a, and the like, so that they do not fall off.

[0049] Furthermore, a guide portion (not shown) having two parallel surfaces facing each other with a transmission end portion 54a (described later) therebetween is provided on the surface of the cover 43 facing the inside of the housing mounting portion 42a. The guide portion (particularly the two parallel surfaces) restricts the transmission end portion 54a to move back and forth in a linear direction.

[0050] The transmission body 5 transmits the driving force generated by the rotation of the operated part 7 to the stopper lid 94. The transmission body 5 includes an interposed rotation part 52, a rotation part 53, and a transmission part .

[0051] The interposed rotation part 52 rotates the rotation part 53 when the operated part 7 is pressed and rotated. The interposed rotation part 52 is inserted into the communication hole of the box member 42 in a state where it can rotate relatively to the box member 42, and is supported by the box member 42 and the cover 43. More specifically, one end of the interposed rotation part 52 in the rotation axis direction is supported by the cover 43, and an intermediate part in the rotation axis direction is supported by the box member 42. An annular seal member (not shown) is disposed between the outer periphery of the part of the interposed rotation part 52 that is disposed in the communication hole and the box member 42 (particularly the part that forms the communication hole), and this seal member prevents water from entering the housing mounting part 42a from inside the case member 4.

[0052] Furthermore, two arms (not shown) are provided at a portion of intervening rotation part 52 that is arranged inside case member 4 (i.e., the space in which operated part 7 is accommodated). These arms extend toward opening 41c and, for example, form an eight-shape in which the distance between them gradually increases as they move away from the rotation center of intervening rotation part 52. The operated part 7 (particularly the turning locking part described below) is arranged between these arms, so that as the operated part 7 rotates, a force is applied from the operated part 7 to the arms, causing intervening rotation part 52 to rotate.

[0053] Furthermore, the portion of the intervening rotation part 52 that is arranged within the accommodating mounting part 42a is provided with a mounting recess 52a that opens to the outer periphery and an upstream gear part 52b that is provided on the opposite side of the mounting recess 52a across the rotation center of the intervening rotation part 52.

[0054] The mounting recess 52 a is a recess in which the other end portion of the force reversing mechanism 61 (described later) is disposed, and is used to connect the force reversing mechanism 61 and the interposed rotation part 52 .

[0055] The upstream gear portion 52 b is meshed with a downstream gear portion of the rotating portion 53 , which will be described later, and transmits the driving force generated by the rotation of the intermediate rotating portion 52 to the rotating portion 53 .

[0056] The rotating part 53 is disposed between the intervening rotating part 52 and the transmission part 54, and is attached to the side part of the box member 42 in a state where it can rotate about a predetermined rotation axis R1. The rotating part 53 has a shape in which a downstream gear part (not shown) and a disk part 53a are coaxially arranged along the direction of the rotation axis R1.

[0057] As described above, the downstream gear portion is meshed with the upstream gear portion 52b, and rotates by receiving a rotational force transmitted from the intervening rotation portion 52. The rotation radius of the upstream gear portion 52b (i.e., the distance from the rotation center of the intervening rotation portion 52 to the outer periphery of the upstream gear portion 52b) is larger than the rotation radius of the downstream gear portion (i.e., the distance from the rotation axis R1, which is the rotation center of the rotating portion 53, to the outer periphery of the downstream gear portion). This makes it possible to increase the rotation angle of the rotating portion 53 larger than the rotation angles of the operated portion 7 and the intervening rotation portion 52.

[0058] The disk portion 53a is disk-shaped and has a larger diameter than the downstream gear portion, and is provided with a cylindrical protrusion 53b on the outer periphery of the end face opposite the downstream gear portion. The protrusion 53b is connected to the transmission portion 54, and is capable of reciprocating along an arc-shaped path centered on the rotation axis R1 when the rotating portion 53 rotates.

[0059] More specifically, the protrusion 53b is capable of reciprocating movement across an orthogonal imaginary plane Vx that includes the rotation axis R1 and is perpendicular to the direction of reciprocating movement of the transmission end portion 54a. Note that the direction of the thick arrow in Fig. 4 is the forward movement direction of the protrusion 53b, and the direction of the dotted arrow is the return movement direction of the protrusion 53b.

[0060] When the drain outlet 113 is in the open state, the protrusion 53b is arranged to be positioned at the top dead center position, where its center (central axis) overlaps with a first imaginary plane V1 that includes the rotation axis R1 and is parallel to the reciprocating direction of the transmission end portion 54a (described later) (see FIG. 7). In other words, when the drain outlet 113 is in the open state, the protrusion 53b is arranged to be positioned at the furthest forward movement position along the reciprocating direction of the transmission end portion 54a. When the protrusion 53b reaches the top dead center position, the rotating portion 53 is restricted from further forward movement by contacting a restricting means (not shown) or the like.

[0061] On the other hand, when the drain outlet 113 is in a closed state, the protrusion 53b is positioned at a position before the bottom dead center position, which is a position 180° offset from the top dead center position around the rotation axis R1 (see Figure 3, etc.).

[0062] The transmission part 54 is for transmitting the driving force generated by the rotation of the rotation part 53 to the plug lid 94 side, and includes a transmission end part 54a and an inner wire 54b.

[0063] The transmission end portion 54a is provided at the end of the transmission portion 54 on the operating device 2 side, and as described above, is restricted to reciprocating movement in a linear direction by the guide portion of the cover 43. Furthermore, the rotation of the transmission end portion 54a is restricted by the cover 43 and the box member 42. Note that the transmission end portion 54a may be restricted to reciprocating movement in a linear direction by a component other than the cover 43.

[0064] Furthermore, a connecting hole 54c through which the protrusion 53b is inserted is formed in the transmission end portion 54a. A protrusion contact surface 54d and a return-action protrusion contact surface 54e are provided at the portion of the transmission end portion 54a where the connecting hole 54c is formed, facing each other along the reciprocating direction of the transmission end portion 54a. The protrusion contact surface 54d and the return-action protrusion contact surface 54e are parallel planes that are perpendicular to the moving direction of the transmission end portion 54a. The protrusion 53b is sandwiched between the protrusion contact surface 54d and the return-action protrusion contact surface 54e, thereby connecting the protrusion 53b and the transmission end portion 54a.

[0065] In addition, when the protrusion 53b moves along the arc-shaped path, the protrusion 53b moves in a direction perpendicular to the reciprocating direction of the transmission end portion 54a. The connecting hole 54c is relatively wide so as not to hinder the movement of the protrusion 53b in this perpendicular direction. As a result, the protrusion contact surface 54d is pressed by the protrusion 53b when the protrusion 53b moves forward along the arc-shaped path to switch the drain outlet 113 from the closed state to the open state, and is configured to allow the protrusion 53b to slide in a direction perpendicular to the reciprocating direction of the transmission end portion 54a. Furthermore, the return-motion protrusion contact surface 54e is pressed by the protrusion 53b when the protrusion 53b moves backward along the arc-shaped path to switch the drain outlet 113 from the open state to the closed state, and is configured to allow the protrusion 53b to slide in a direction perpendicular to the reciprocating direction of the transmission end portion 54a.

[0066] The distance between the two surfaces 54d and 54e along the direction of movement of the transmission end portion 54a is set to be approximately the same as the outer diameter of the protrusion 53b (for example, 1.0 to 1.1 times the outer diameter of the protrusion 53b), so that when the protrusion 53b moves, the driving force caused by the movement is immediately applied to the transmission end portion 54a.

[0067] The inner wire 54b is configured, for example, of a core coil or stranded wire made of a metal wire, and its end is connected to the transmission end portion 54a. The inner wire 54b is inserted through the inner periphery of a long, cylindrical tube member 54f, and moves back and forth within the tube member 54f as the operated portion 7 rotates.

[0068] One end of the tube member 54f is provided with a flange-shaped flared portion, and this flared portion is disposed in the tube mounting portion 42b and sandwiched between the box member 42 and the cover 43, thereby mounting one end of the tube member 54f to the housing mounting portion 42a. Meanwhile, the other end of the tube member 54f is disposed on the drain outlet device 9 side and mounted to the cylindrical case 93a (see FIG. 2). As a result, the inner wire 54b is guided from the operating device 2 side to the drain outlet device 9 side by the tube member 54f.

[0069] The biasing force applying portion 6 is disposed within the housing mounting portion 42a, and applies a biasing force to the rotating portion 53 via the interposed rotating portion 52. The biasing force applying portion 6 includes an applied force reversing mechanism 61 that is rod-shaped overall, and a spring portion 62 (see FIG. 4, etc.; not shown in FIG. 3, etc.) that is formed by spirally winding a predetermined metal wire.

[0070] The force reversal mechanism 61 includes a cylindrical cylinder 61a having one closed end and a rod-shaped portion 61b inserted into the cylinder 61a. One end of the force reversal mechanism 61, i.e., one end of the cylinder 61a, is pivotally supported by the case member 4 (box member 42) around a one-end rotation axis L1 parallel to the rotation axis R1 (for convenience, a protrusion provided on the one end of the cylinder 61a and constituting the rotation center of the one end is omitted in FIG. 4 and other drawings). The other end of the force reversal mechanism 61, i.e., the other end of the rod-shaped portion 61b protruding from the other end opening of the cylinder 61a, is disposed in the mounting recess 52a, and is pivotally supported by the interposed rotation member 52 around a one-end rotation axis L2 parallel to the rotation axis R1. The other end portion of the force reversal mechanism 61 (the other end portion of the rod-shaped portion 61b) is configured to move along an arc-shaped path centered on the rotation center of the interposed rotation portion 52 when the interposed rotation portion 52 rotates.

[0071] The spring portion 62 is disposed in a compressed state between one end portion (the portion that abuts the bottom of the cylinder portion 61a) and the other end portion (the other end portion of the rod-shaped portion 61b) of the force-applying reversing mechanism 61. The spring portion 62 and the force-applying reversing mechanism 61 are provided in a position where they do not pass through the rotation center of the intervening rotation portion 52 when the intervening rotation portion 52 rotates. This makes it possible to support one end portion of the intervening rotation portion 52 in the rotation axis direction by the cover 43, as described above.

[0072] Furthermore, when the drain outlet 113 is in an open state, i.e., when the operated part 7 is protruding from the opening 41c of the case member 4 (see Figure 7, etc.), a force is applied from the spring part 62 to the rotating part 53 in a direction that inhibits the return movement of the protrusion part 53b (movement in the direction indicated by the dotted arrow in Figure 7).

[0073] On the other hand, during the return movement of the protrusion 53b due to the rotation of the operated part 7, the other end side rotation axis L2 crosses a second imaginary plane V2 including the one end side rotation axis L1 and the rotation center of the intervening rotation part 52, thereby reversing the direction of the force applied from the spring part 62 to the rotation part 53, and the spring part 62 applies a force to the rotation part 53 in a direction that promotes the return movement of the protrusion 53b.

[0074] Furthermore, when drain outlet 113 is in a closed state, that is, when operated portion 7 is not protruding from opening 41c of case member 4 (see FIG. 4, etc.), spring portion 62 applies a force to rotating portion 53 in a direction that inhibits forward movement of protrusion 53b (movement in the direction indicated by the thick arrow in FIG. 4). Therefore, spring portion 62 can more reliably maintain drain outlet 113 in an open state and a closed state.

[0075] On the other hand, during the forward movement of the protrusion 53b due to the rotation of the operated part 7, the other-end rotation axis L2 crosses the second imaginary plane V2, thereby reversing the direction of the force applied from the spring part 62 to the rotating part 53, and the spring part 62 applies a force to the rotating part 53 in a direction that promotes the forward movement of the protrusion 53b. Therefore, the applied force reversal mechanism 61 can reverse the direction of the force applied from the spring part 62 to the rotating part 53 during the reciprocating movement of the protrusion 53b due to the rotation of the operated part 7.

[0076] Therefore, in this embodiment, when the drain outlet 113 is in the open state, a protruding / moving portion 71a (described later) of the operated portion 7 is pressed and moved, and when the other-end side rotation axis L2 crosses the second imaginary plane V2, a force is applied from the spring portion 62 to the rotating portion 53 in a direction that presses and moves the protruding / moving portion 71a. On the other hand, when the drain outlet 113 is in the closed state, a retracting / moving portion 71b (described later) of the operated portion 7 is pressed and moved, and when the other-end side rotation axis L2 crosses the second imaginary plane V2, a force is applied from the spring portion 62 to the rotating portion 53 in a direction that presses and moves the retracting / moving portion 71b. In other words, when switching the open / closed state of the drain outlet 113, if the operated portion 7 is moved to a certain extent, a force is applied from the spring portion 62 to the rotating portion 53 in a direction that assists in switching the open / closed state.

[0077] The operated part 7 is a part that is operated by the user when opening or closing the drain outlet 113. The operated part 7 is attached to the shaft part of the flange member 41 and is rotatable around the shaft part. Therefore, the operated part 7 in this embodiment moves back and forth by rotating. The operated part 7 includes a pressed part 71 and a swivel plate part 72 (see Figure 6, etc.).

[0078] The pressed portion 71 is plate-shaped and has a rectangular shape corresponding to the opening 41c. The pressed portion 71 has a protruding / moving portion 71a and a retracting / moving portion 71b that are positioned on either side of the rotation center of the pressed portion 71. The protruding / moving portion 71a is located below the rotation center of the operated portion 7 when viewed from the front (when viewed from the washing area 101 side), and protrudes from the opening 41c as the operated portion 7 rotates. The protruding / moving portion 71a protrudes from the opening 41c when the drain outlet 113 is in the open state, and is pressed when switching the drain outlet 113 from the open state to the closed state.

[0079] On the other hand, the retracting movement portion 71b is a portion that is located above the rotation center of the operated portion 7 when viewed from the front, and is a portion that retracts into the case member 4 as the operated portion 7 rotates. The retracting movement portion 71b is pressed when switching the drain outlet 113 from a closed state to an open state. Therefore, by pressing the protruding movement portion 71a or the retracting movement portion 71b, the operated portion 7 is rotated, and the open / closed state of the drain outlet 113 can be switched.

[0080] The swivel plate portion 72 is a plate-shaped portion that protrudes from the rear surface side of the pressed portion 71 toward the inside of the case member 4, and is provided with a cylindrical swivel locking portion (not shown) at its tip portion (the end portion on the intervening rotating portion 52 side). The swivel locking portion is disposed between the two arm portions. As a result, when the swivel plate portion 72 rotates in response to an operation on the operated portion 7, the intervening rotating portion 52 and the rotating portion 53 rotate, and ultimately the transmission portion 54 moves back and forth.

[0081] In the drain plug device 1 described above, when the drain outlet 113 is in the closed state, the surfaces of the protruding and moving portion 71a and the retracting and moving portion 71b of the operated portion 7 are substantially flush with the end face 41d (see FIG. 3). Note that the term "substantially flush" does not mean strictly flush, but also includes cases where there are slight irregularities, gaps, or steps (for example, 5 mm or less, more preferably 3 mm or less) between the surface of the protruding and moving portion 71a, etc., and the end face 41d. In this state, when the drain outlet 113 is switched to the open state, the retracting and moving portion 71b is pressed to rotate the operated portion 7 to one side (moving forward), which causes the intervening rotating portion 52 to rotate to one side, and ultimately causes the rotating portion 53 to rotate to one side (moving forward). Then, protrusion 53b moves forward along the arc-shaped path, and protrusion 53b presses protrusion contact surface 54d, thereby moving transmission part 54 forward. As a result, support shaft 93b and plug lid 94 move forward (upward), and drain outlet 113 is set to the open state.

[0082] Furthermore, when the drain outlet 113 is in the open state, the protrusion 53b is positioned at the top dead center position. As a result, when the drain outlet 113 is in the open state, for example, if a force in the backward (downward) direction is applied to the plug lid 94 due to the weight of the plug lid 94 or the biasing force from the return spring 93c, and even if a force in the backward direction is applied to the transmission end portion 54a, the rotation of the rotating portion 53 is restricted, and the transmission portion 54 is locked in the forward movement state. Then, by locking the transmission portion 54 in the forward movement state, the plug lid 94 is maintained in the forward movement (upward movement) state, i.e., the open state of the drain outlet 113. Therefore, in this embodiment, the transmission end portion 54a, the rotating portion 53, etc. form a locking mechanism 57 (see FIGS. 4 and 6) that locks the transmission portion 54 in the forward movement state.

[0083] Furthermore, when the drain outlet 113 is in the open state, the spring portion 62 applies a force to the rotating portion 53 in a direction that inhibits the return movement of the protrusion 53b. In other words, the spring portion 62 assists in locking the transmission portion 54. Therefore, in this embodiment, the biasing force applying portion 6 also constitutes a part of the locking mechanism 57.

[0084] When drain outlet 113 is in the open state, if a relatively large force in the backward (downward) direction is applied to plug 94, for example, by stepping on plug 94 or placing a heavy object on it, absorber spring 93d will be compressed and deformed, and a relatively large force in the backward direction will be applied to transmission end portion 54a. However, even when such a force in the backward direction is applied to transmission end portion 54a, transmission portion 54 will be maintained in the forward moving state by lock mechanism 57, and thus drain outlet 113 will also be maintained in the open state.

[0085] Furthermore, when the drain outlet 113 is in the open state, the operated part 7 is in a state in which the protruding and moving part 71a protrudes from the end surface 41d and the retracting and moving part 71b is retracted into the case member 4 (see FIGS. 5, 6, etc.). In this state, when the drain outlet 113 is switched to the closed state, the protruding and moving part 71a is pressed to rotate the operated part 7 to the other side (returning), which causes the intervening rotating part 52 to rotate to the other side. Then, the rotating part 53 rotates to the other side, and the protruding part 53b returns along the arc-shaped path, which causes the transmitting part 54 to return. More specifically, when the rotating part 53 rotates, the lock of the transmission part 54 is released, and the transmission part 54 returns due to the operating force applied to the operated part 7 (the force applied from the protrusion part 53b to the protrusion contact surface 54e during the return movement), the weight of the plug lid 94, and the biasing force applied by the return spring 93c. Then, when the plug lid 94 returns (moves downward) in accordance with the return movement of the transmission part 54, the drain outlet 113 is closed.

[0086] When the drain outlet 113 is in the open state and the surfaces of the protruding and retracting portions 71a and 71b are substantially flush with the end face 41d, the opening 41c is closed by the operated portion 7, and there is almost no gap (for example, a gap of 1 mm or less) between the case member 4 and the operated portion 7 (pressed portion 71). From the perspective of improving appearance, the smaller the gap, the better. Therefore, it is more preferable to set the size of the gap to 0.5 mm or less, and even more preferable to set the size of the gap to 0.3 mm or less. It is most preferable to configure the case member 4 and the operated portion 7 so that there is no gap between them.

[0087] As described above, according to this embodiment, by positioning the protrusion 53b at the top dead center position, when the drain outlet 113 is in the open state, a force in the backward direction is applied to the plug lid 94, and even if a force in the backward direction is applied to the transmission end portion 54a, the transmission unit 54 can be locked in the forward movement state. In particular, in this embodiment, because the protrusion 53b is positioned at the top dead center position, the rotating unit 53 does not rotate even if a force in the backward direction is applied to the transmission end portion 54a, and the transmission unit 54 can be more reliably maintained in the locked state. Therefore, the structure of the locking mechanism 57 can be simplified, which is advantageous in terms of productivity and cost. Furthermore, the locking mechanism 57 can prevent the user from unintentionally switching between the open and closed states, thereby improving usability for the user.

[0088] Furthermore, by using the spring portion 62, the transmission portion 54 can be more reliably maintained in the locked state, and consequently the drain outlet 113 can be more reliably maintained in the open state.

[0089] In addition, by the force reversal mechanism 61, the direction of the force applied from the spring portion 62 to the rotating portion 53 while the protrusion 53b is returning is reversed from a force that would hinder the return movement of the protrusion 53b and the transmission end portion 54a to a force that promotes the return movement of the protrusion 53b and the transmission end portion 54a. Therefore, when the operated portion 7 is operated to switch the open / closed state of the drain outlet 113, the force applied from the spring portion 62 can be used as an assist force to help with the switch. This further improves the operability of switching the open / closed state of the drain outlet 113.

[0090] Furthermore, according to this embodiment, the force reversing mechanism 61 can be realized with a relatively simple configuration, which can more reliably prevent the structure from becoming complicated and suppress increases in costs.

[0091] Furthermore, because the spring portion 62 is provided in a compressed state, the drain plug device 1 can be made smaller than when the spring portion is provided in a natural length state or an extended state.

[0092] Additionally, even if a relatively large force is applied in the backward (downward) direction to the plug lid 94, the absorber spring 93d can more reliably prevent deformation or damage to the transmission part 54, the protrusion 53b, etc. Therefore, the operational stability and lifespan of the drain plug device 1 can be improved.

[0093] The present invention is not limited to the above-described embodiment, and may be implemented as follows: Of course, other applications and modifications not exemplified below are also possible.

[0094] (a) In the above embodiment, the protrusion 53b is positioned at the top dead center position, so that even if a force in the backward (downward) direction is applied to the plug cover 94 when the drain outlet 113 is in the open state, the rotation of the rotating part 53 is restricted and the transmission part 54 can be locked in the forward moving position.

[0095] In response to this, the rotating part 53 can be configured so that when the protrusion 53b moves forward to a position beyond the top dead center position, further rotation is restricted by coming into contact with a regulating means not shown, and when the drain outlet 113 is in the open state, as shown in Figures 9 and 10, the protrusion 53b is positioned at a position beyond the top dead center position, so that even if a force in the backward (downward) direction is applied to the plug cover 94 when the drain outlet 113 is in the open state, the rotation of the rotating part 53 is restricted and the transmission part 54 can be locked in the forward moving position.

[0096] In this configuration, as in the above embodiment, the transmission part 54 can be more reliably maintained in the locked state, and consequently the drain outlet 113 can be more reliably maintained in the open state.

[0097] Furthermore, even if there is a slight difference in the position of protrusion 53b when drain outlet 113 is in the open state (for example, even if protrusion 53b is positioned slightly forward from the intended design position), transmission unit 54 can be locked more reliably. Therefore, the operational stability of drain plug device 1 can be further improved.

[0098] (b) As shown in Figure 11, when the drain outlet 113 is in the open state, the protrusion 53b is positioned near and in front of the top dead center position, and the frictional force generated by the contact between the protrusion 53b and the protrusion contact surface 54d in a direction that restricts the sliding movement of the protrusion 53b is utilized to restrict the rotation of the rotating part 53, so that the transmission part 54 can be locked in a forward moving state even when a force in the backward moving direction is applied to the plug cover 94 when the drain outlet 113 is in the open state.

[0099] In this configuration, the amount of forward movement of the protrusion 53b (the amount of rotation of the rotation part 53) when locking the transmission part 54 can be made relatively small, thereby improving operability.

[0100] The frictional force in the direction restricting the sliding movement of protrusion 53b can be adjusted by adjusting factors such as the material, shape, and surface roughness of protrusion 53b and protrusion contact surface 54d, the contact area between protrusion 53b and protrusion contact surface 54d, and the position (angle) of protrusion 53b when drain outlet 113 is in the open state. For example, the position (angle) of protrusion 53b when drain outlet 113 is in the open state is preferably set so that the center of protrusion 53b is positioned at a position offset by 10° or less (more preferably 5° or less) from the top dead center position around rotation axis R1.

[0101] (c) In the above embodiment, the protruding / moving portion 71a is located below the rotation center of the operated portion 7, and the retracting / moving portion 71b is located above the rotation center, but the positional relationship between the protruding / moving portion 71a and the retracting / moving portion 71b may be reversed. Furthermore, the direction in which the rotation center of the operated portion 7 extends does not necessarily have to be horizontal as in the above embodiment, and may be vertical or diagonally horizontal.

[0102] (d) In the above embodiment, the operated part 7 is configured so that its entirety fits within the case member 4 when the drain outlet 113 is in the closed state, and so that a portion of it protrudes outside the case member 4 when the drain outlet 113 is in the open state; however, the state of the operated part 7 when the drain outlet 113 is in the open state or the closed state may be changed as appropriate. Therefore, for example, the operated part 7 may be configured so that its entirety fits within the case member 4 whether the drain outlet 113 is in the open state or the closed state. Furthermore, the operated part 7 may be configured so that a portion of it protrudes outside the case member 4 whether the drain outlet 113 is in the open state or the closed state.

[0103] (e) In the above embodiment, the operated unit 7 is configured to reciprocate by rotating, but it may also reciprocate by moving along a linear path. Therefore, for example, an operation button or an operation knob that can reciprocate along a linear path may be used as the operated unit. When such an operation button or operation knob is used, for example, a rack that reciprocates in accordance with the movement of the operation button or operation knob may be engaged with the downstream gear of the rotating unit 53, so that the rotating unit 53 rotates in accordance with the reciprocating movement of the operation button or operation knob.

[0104] Furthermore, in the above embodiment, the case member 4, the operated portion 7, etc. are attached to the apron 120, but they may be attached to a location other than the apron 120 (for example, the bathtub, etc.).

[0105] (f) In the above embodiment, the other end portion of the force reversing mechanism 61 is attached rotatably to the intervening rotation unit 52. However, in cases where the intervening rotation unit 52 is not provided, the other end portion of the force reversing mechanism 61 may be attached rotatably to the rotation unit 53 about a other end rotation axis parallel to the rotation axis R1. The other end rotation axis may cross a second imaginary plane including the one end rotation axis L1 and the rotation center (rotation axis R1) of the rotation unit 53 during the return movement of the protrusion 53b, thereby reversing the direction of the force applied from the spring unit 62 to the rotation unit 53. In cases where the intervening rotation unit 52 is not provided, the driving force generated by the movement of the operated unit 7 may be transmitted to the rotation unit 53 directly or via a component other than the intervening rotation unit 52.

[0106] (g) In the above embodiment, the operated part 7 rotates (moves back and forth) when operated by the user, but the operated part may also be one that moves back and forth when subjected to force from a driving source such as a motor.

[0107] (h) In the above embodiment, a bathtub 110 is used as an example of a tank body, but the tank body to which the technical concept of the present invention can be applied is not limited to a bathtub. Therefore, for example, the technical concept of the present invention may be applied to a tank body such as a washbowl or a kitchen sink. [Explanation of symbols]

[0108] 1...drain plug device, 7...operated part, 52...intervening rotating part, 53...rotating part, 53b...projection part, 54...transmission part, 54a...transmission end part, 54d...projection contact surface, 54e...projection contact surface during return movement, 57...locking mechanism, 61...applied force reversal mechanism, 62...spring part, 93d...absorber spring (shock absorber means), 94...plug cover, 110...bathtub (tank body), 113...drain outlet, L1...one end side rotating shaft, L2...other end side rotating shaft, R1...rotating shaft (of rotating part), V1...imaginary plane, V2...second imaginary plane.

Claims

1. The drain plug device has a plug lid for opening and closing the drain outlet of a tank body, an operated part that can move back and forth, and a transmission part that can move back and forth in accordance with the reciprocating movement of the operated part and transmits the driving force caused by the movement of the operated part to the plug lid side, and is used in a drain plug device that can move back and forth with the operated part moving back and forth, causing the transmission part to move back and forth to move the plug lid to open the drain outlet, while causing the operated part to move back and forth to move the transmission part to close the drain outlet, A locking mechanism for maintaining the drain outlet in an open state by locking the transmission part in a forward movement state, a rotating part that rotates about a predetermined rotation axis as the operated part moves back and forth; a transmission end portion provided at an end of the transmission portion and restricted to reciprocating in a linear direction; the rotating portion has a protrusion that can reciprocate along an arc-shaped path centered on the rotation axis when the rotating portion rotates, The transmission end portion has a protrusion contact surface that is pressed against the protrusion portion when the protrusion portion moves forward along an arc-shaped path to switch the drain outlet from a closed state to an open state, and is configured to allow sliding movement of the protrusion portion along a direction perpendicular to the reciprocating movement direction of the transmission end portion, When the drain outlet is in an open state and a force in the backward direction is applied to the plug cover, the force in the backward direction is applied to the transmission end portion, When the drain outlet is in the open state, the protrusion is positioned at or near the top dead center position, where its center overlaps with an imaginary plane that includes the pivot axis and is parallel to the direction of reciprocating movement of the transmission end part, so that even if a force in the reciprocating direction is applied to the plug cover when the drain outlet is in the open state, the locking mechanism is configured to restrict the rotation of the pivot part and lock the transmission part in a forward moving position.

2. The locking mechanism described in claim 1 is characterized in that when the drain outlet is in an open state, the protrusion is positioned just before the top dead center position and in the vicinity of the top dead center position, and by utilizing the frictional force generated by contact between the protrusion and the protrusion contact surface in a direction that restricts the sliding movement of the protrusion, even if a force in the return direction is applied to the plug cover when the drain outlet is in an open state, the rotation of the rotating part is restricted and the transmission part can be locked in a forward moving position.

3. The locking mechanism described in claim 1, characterized in that when the drain outlet is in the open state, the protrusion is positioned at the top dead center position, so that even if a force in the backward direction is applied to the plug cover when the drain outlet is in the open state, the rotation of the rotating part is restricted and the transmission part can be locked in a forward moving state.

4. the rotating portion is configured such that further rotation is restricted when the protrusion moves forward to a position beyond the top dead center position, The locking mechanism described in claim 1, characterized in that when the drain outlet is in the open state, the protrusion is positioned at a position beyond the top dead center position, so that even if a force in the backward direction is applied to the plug cover when the drain outlet is in the open state, the rotation of the rotating part is restricted and the transmission part can be locked in a forward moving state.

5. The locking mechanism described in claim 1, characterized in that it is provided with a spring portion that assists in locking the transmission portion by applying a force to the rotating portion in a direction that inhibits the return movement of the protrusion portion when the drain outlet is in an open state.

6. the transmission end portion has a return-motion protrusion contact surface that is pressed against the protrusion when the protrusion moves back along a circular arc path to switch the drain outlet from an open state to a closed state; 6. The locking mechanism according to claim 5, further comprising a force reversal mechanism that can reverse the direction of the force applied from the spring portion to the rotating portion during the return movement of the protrusion portion.

7. The force reversal mechanism includes: a first end portion rotatably supported about a first end rotation axis parallel to the rotation axis; the other end portion is attached to the rotating part or an intermediate rotating part that is rotatable about an axis parallel to the rotating shaft and that is configured so that the driving force due to the rotation of the intermediate rotating part is transmitted to the rotating part, and the other end portion is attached to the intermediate rotating part in a state that the other end portion is rotatable about an axis parallel to the rotating shaft; The other end portion moves along an arcuate path when the rotating portion or the intervening rotating portion to which the other end portion is attached rotates, and the spring portion is disposed in a compressed state between the one end portion and the other end portion, 7. The locking mechanism according to claim 6, wherein the other-end side rotation shaft crosses a second imaginary plane that includes the one-end side rotation shaft and a rotation center of the rotation part or the intervening rotation part to which the other-end side portion is attached during the returning movement of the protrusion, thereby reversing the direction of the force applied from the spring part to the rotation part.

8. The locking mechanism described in claim 1, characterized in that the drain plug device has a shock absorber means that can absorb the load applied to the transmission part by compressively deforming when a force in the reciprocating direction is applied to the plug cover when the drain outlet is in an open state.

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