JP5145608B2 - Latch device - Google Patents

Description

  The present invention relates to a latch device, and particularly to a latch device suitable for detachably supporting a seat with respect to a vehicle body.

  An example of this type of latch device is described in Patent Document 1. In this latch device, a latch and a locking plate are rotatably provided on a base plate having a notch groove. The latch has a portion that moves forward and backward with respect to the notch groove of the base plate by rotating. The locking plate is engaged with and separated from the latch by rotating. The locking plate has a function of restricting rotation of the latch in the opening direction in which the latch retracts when the latch rotates in the meshing direction and engages at a predetermined meshing position where the latch advances into the notch groove. Have.

  A return spring is interposed between the latch and the locking plate. The return spring biases the locking plate in a direction in which the locking plate is always close to the latch, and biases the latch to retreat and rotate when the locking plate is separated from the latch that has advanced into the notch groove. It is a tension spring.

  Further, the latch device includes a cam lever. The cam lever is always urged in the direction close to the latch by the spring force of the cam lever spring interposed between the cam lever and the base plate.

  The latch device configured as described above is provided, for example, in the backrest portion of the seat, and when the backrest portion is moved close to the striker provided in the vehicle body, the striker enters the notch groove of the base plate. As a result, the latch rotates in the meshing direction against the spring force of the return spring and the spring force of the cam lever spring, and the latch advances into the notch groove. When the latch advances into the notch groove and reaches a predetermined engagement position, the locking plate is engaged with the latch by the return spring, and the rotation of the latch in the opening direction is restricted. As a result, the deviation of the striker with respect to the notch groove is restricted, and the backrest portion of the seat can be fixed to the vehicle body.

  Furthermore, after the latch rotates to the meshing position, the latch is further rotated in the meshing direction via the cam lever by the spring force of the cam lever spring, so that the striker is held between the latch and the base plate. It becomes. For this reason, even when vibration is applied to the vehicle, there is no possibility that the striker and the latch device will rattle.

  On the other hand, when the locking plate is rotated away from the latch from the above state, the engagement with the latch is released and the cam lever is separated from the latch by engaging with the locking plate, and the spring force of the return spring is released. As a result of the rotation of the latch in the opening direction, the engagement with the striker is released. Thereby, the striker can be deviated from the notch groove of the base plate, and the seat back portion can be stored in a folded state with respect to the seat seat portion.

JP-T-2006-516502

  By the way, in the latch device described above, when the latch rotates as the striker enters, the extension amount of the return spring gradually increases in accordance with the rotation amount. In other words, as the rotation of the latch in the meshing direction proceeds, the rotational drag force against the rotation in the meshing direction acting from the return spring increases. For this reason, the engagement load when the locking plate is engaged with the latch, that is, the operating force when fixing the seat back portion to the vehicle body must be increased, and it is not necessarily preferable when considering usability. Absent. In particular, in a latch device equipped with a cam lever, the spring force of the cam lever spring needs to be large enough to move the meshed latch to the restrained state, so a cam lever spring with a larger spring force is applied. The above-mentioned problem becomes more prominent.

  In view of the above circumstances, an object of the present invention is to provide a latch device capable of improving the operability by reducing the meshing load when the latch and the locking plate are shifted to the meshing state.

  In order to achieve the above object, the latch device according to the present invention rotates the latch in the meshing direction against the spring force of the return spring from the open position to the predetermined meshing position by the striker entering the meshing groove of the latch. In the latch device that regulates the rotation of the latch in the opening direction by engaging the locking plate with the rotated latch, and holds the striker and the latch in a meshed state, the return spring is latched via one end. Torsion coil springs that act against the latch against rotation in the meshing direction by pressing the peripheral surface of the latch, and after the striker enters the peripheral surface of the latch, the latch rotates in the meshing direction. Thus, a spring control cam surface for reducing the rotational drag force caused by the return spring is formed before reaching the meshing position.

  Further, the present invention is the above-described latch device, wherein the cam lever is moved from the peripheral surface of the latch before the amount of rotation of the latch exceeds a preset angle after the latch rotates in the meshing direction when the striker enters. It separates, and when it becomes more than the said setting angle, the surrounding surface of a latch is pressed, It is characterized by the above-mentioned.

  According to the present invention, in the above-described latch device, the return spring is pressed into the latch by pressing the peripheral surface of the latch through the locking plate after the striker enters the latch and before reaching the meshing position. On the other hand, a rotational drag against the rotation in the meshing direction is applied to the spring control cam surface. A centripetal cam portion that applies a pressing force of the latch by one end portion toward the rotation center of the latch, and the latch is a torsion coil spring that is separate from the return spring, at least from the meshing position A restraint return spring is provided for applying a rotational drag force against the restraint during the transition to the restraint state.

  According to the present invention, in the above-described latch device, the return spring is pressed into the latch by pressing the peripheral surface of the latch through the locking plate after the striker enters the latch and before reaching the meshing position. On the other hand, a rotational drag against the rotation in the meshing direction is applied to the spring control cam surface. A centripetal cam portion that causes the pressing force of the latch by one end portion to act toward the rotation center of the latch, and further, the cam lever moves in the restraint releasing direction from the latch in the restrained state, and the locking plate When the engagement state of the locking plate is released, the locking plate interlocks with the disengagement movement, contacts the latch and rotates it in the release direction. Characterized by comprising fruitless lever.

  According to the present invention, a torsion coil spring is applied as a return spring, and the rotational drag force from the torsion coil spring is reduced midway by the action of a spring control cam surface formed on the peripheral surface of the latch. For this reason, the rotational drag from the return spring is reduced regardless of the amount of rotation of the latch in the meshing direction, and the meshing load when the locking plate is engaged with the latch is reduced to improve the operability. Is possible.

1A and 1B show a latch device according to a first embodiment of the present invention. FIG. 1A is a diagram showing a state in which the latch is disposed at an open position, and FIG. The figure which shows the state which rotated, (c) is a figure which shows the state by which the latch was arrange | positioned in a meshing position, (d) is a figure which shows a restraint state. FIG. 2 is a perspective view of the latch device shown in FIG. FIG. 3 is a perspective view of the latch device shown in FIG. 1 viewed from another angle. FIG. 4 is an exploded perspective view of the latch device shown in FIG. FIG. 5 is a diagram showing a latch applied to the latch device shown in FIG. FIG. 6 is a side view conceptually showing a vehicle seat to which the latch device shown in FIG. 1 is applied. FIG. 7 is a graph showing the relationship between the amount of rotation of the latch and the rotational resistance against the rotation in the meshing direction in the latch device shown in FIG. FIG. 8 is a graph showing the relationship between the release operation amount when releasing the meshing state of the latch and the striker in the latch device shown in FIG. 1 and the rotational resistance against rotation in the direction of releasing the meshing. FIG. 9 is a diagram sequentially illustrating the operation of the latch device according to the second embodiment of the present invention. FIG. 10 is a diagram showing a latch applied to the latch device shown in FIG. FIG. 11 is a diagram sequentially illustrating the operation of the latch device according to the third embodiment of the present invention. FIG. 12 is a diagram showing a latch applied to the latch device shown in FIG.

  Exemplary embodiments of a latch device according to the present invention will be explained below in detail with reference to the accompanying drawings.

(Embodiment 1)
1 to 5 show a latch device according to Embodiment 1 of the present invention. As shown in FIG. 6, the latch device exemplified here applies to a vehicle seat S in which a backrest portion SS is rotatably supported at a rear end edge portion of a seating portion SZ, and is provided in a vehicle main body B. The backrest SS is detachably fixed to the vehicle body B by engaging with the striker ST. The backrest SS includes a base plate 10 and a cover plate 20.

  Each of the base plate 10 and the cover plate 20 is a metal plate-like member, and is provided on the cover plate 20 with two shaft members 30 and 40 interposed therebetween as shown in FIGS. By engaging the engagement connecting pieces 22 with the base plate 10, they are connected to each other while facing each other.

  The base plate 10 and the cover plate 20 are formed with entrance grooves 11 and 21 at portions facing each other. The extension directions of the entrance grooves 11 and 21 are the center lines and the above-described portions are respectively provided on one side and the other side. The shaft members 30, 40 are disposed. The entrance grooves 11 and 21 are notches formed from the outer peripheral edges of the base plate 10 and the cover plate 20 to the central portions thereof, and have a width that allows the striker ST of the vehicle body B to enter.

  The shaft members 30 and 40 each have a cylindrical shape, and the base plate 10 is in a state in which the respective center holes 30a and 40a are aligned with the insertion holes 12, 13, 23, and 24 formed in the base plate 10 and the cover plate 20, respectively. Between the base plate 10 and the cover plate 20, and the parallel bolt insertion holes BH are formed. Although not clearly shown in the drawing, these bolt insertion holes BH are for inserting mounting bolts when the latch device is fixed to the backrest portion SS of the vehicle seat S. That is, when the latch device is attached to the backrest SS, the base plate 10 and the cover plate 20 are firmly fastened together by the mounting bolts fastened to the backrest SS. Therefore, between the two shaft members 30 and 40 and the base plate 10 and the cover plate 20, the shaft members 30 and 40 are merely engaged with the recesses formed around the insertion holes 12, 13, 23 and 24. It is in a state, and no measures are taken to fix both, such as welding and adhesion.

  In this latch device, the latch 31 is supported by one shaft member (hereinafter referred to as “latch shaft member 30”) provided in the vicinity of the back end of the entry grooves 11 and 21 in the base plate 10 and the cover plate 20. In the base plate 10 and the cover plate 20, a locking plate 41 and an open lever are connected to the other shaft member (hereinafter referred to as a “locking shaft member 40”) that is provided at a position further deeper than the back end portions of the entrance grooves 11 and 21. 42 and a return spring 43 are supported.

  The latch 31 is a plate-like member having a meshing groove 31 a that opens on the outer peripheral surface, and can rotate around the axis of the latch shaft member 30 in a manner that the meshing groove 31 a intersects the entry grooves 11 and 21. It is. When the latch 31 is rotated counterclockwise in FIG. 1 (hereinafter referred to as “opening direction”), the opening of the engagement groove 31a is formed in the base plate 10 and the cover plate 20 as shown in FIG. The hook portion 31b positioned on the right side of the engagement groove 31a is in contact with the first stopper piece 14 provided on the base plate 10 and matches the opening of the formed entrance grooves 11 and 21, thereby rotating in the opening direction. (Hereinafter, the position of the latch 31 shown in FIG. 1A is referred to as “open position”). Further, in this open position, the striker contact portion 31c of the latch 31 facing the hook portion 31b across the meshing groove 31a is inclined so as to gradually approach the opening of the entrance grooves 11 and 21 toward the tip. Placed in a state. When the latch 31 is rotated clockwise (hereinafter referred to as “meshing direction”) from the state shown in FIG. 1A, as shown in FIG. As shown in FIG. 1 (c), the hook portion 31b crosses the entrance grooves 11 and 21 so that the openings of the entrance grooves 11 and 21 are closed. (Hereinafter, the position of the latch 31 shown in FIG. 1C is referred to as “meshing position”).

  The locking plate 41 is a lever-like member that extends from the locking shaft member 40 along the entrance grooves 11 and 21 toward the opening end portion thereof, and has a distal end portion that is close to and separated from the outer peripheral surface of the latch 31. It is possible to rotate around the axis of the member 40. An engaging claw portion 41 a is provided at the distal end portion of the locking plate 41, while a restriction projection 41 b is provided at the proximal end portion of the locking plate 41. The engaging claw portion 41 a is a portion that is bent from the distal end portion of the locking plate 41 toward the direction approaching the outer peripheral surface of the latch 31. The restricting projection 41b is a portion extending radially outward from the outer peripheral surface of the base end portion of the locking plate 41, and is in contact with the second stopper piece 15 provided on the base plate 10 so that the locking plate 41 is opposite to the locking plate 41 in FIG. It regulates clockwise rotation. 1A, when the latch 31 is in the open position, the locking projection 41b abuts against the second stopper piece 15 to restrict the counterclockwise rotation. It is held in a state of being separated from the outer peripheral surface. When the latch 31 rotates in the meshing direction from this state, the striker contact portion 31c of the latch 31 contacts the engagement claw portion 41a of the locking plate 41, as shown in FIG. Will be rotated around. Further, when the latch 31 rotates in the meshing direction from this state to the meshing position, as shown in FIG. 1C, when the locking plate 41 is rotated counterclockwise, the engagement claw portion 41a is latched. It is possible to restrict the rotation of the latch 31 in the opening direction by engaging with the striker contact portion 31c of 31. Even when the engaging claw portion 41 a is engaged with the striker contact portion 31 c of the latch 31, the latch 31 can be rotated in the meshing direction.

  As shown in FIGS. 1 and 3, the open lever 42 is a lever member that extends from the locking shaft member 40 to the opening end side along the entrance grooves 11 and 21 like the locking plate 41. It is arranged between the locking plate 41 and the cover plate 20 in such a manner that it can rotate around the 40 axis. The open lever 42 is formed with an engagement notch 42a at the outer periphery of the locking shaft member 40. By engaging the engagement protrusion 41c of the locking plate 41 with the engagement notch 42a, locking is achieved. It is possible to rotate around the axis of the locking shaft member 40 together with the plate 41. As shown in FIGS. 2 and 3, a link member L is supported at the tip of the open lever 42. The link member L is linked to an operation lever (not shown) for operating the latch device.

  1 to 4, the return spring 43 is a torsion coil spring in which a coiled winding portion is inserted into the locking shaft member 40, and one end portion 43a extending radially outward is an open lever. The other end 43 b that protrudes beyond 42 and presses the outer peripheral surface of the latch 31 and extends radially outwardly is engaged with the open lever 42.

  Further, in this latch device, an engagement elastic member 32 and a restraint return spring 33 are supported on the latch shaft member 30. As shown in FIGS. 3 and 4, the engagement elastic member 32 is disposed between the latch 31 and the cover plate 20 in the latch shaft member 30, and has an engagement contact portion 32a on the outer peripheral portion thereof. doing. The engagement contact portion 32 a of the engagement elastic member 32 protrudes in the axial direction of the latch shaft member 30 toward the latch 31, and can contact the contact surface portion 31 d provided on the outer peripheral surface of the latch 31. Is possible. More specifically, as shown in FIGS. 1A to 1D, the latch 31 is engaged until the latch 31 rotates from the open position in the meshing direction and immediately before the meshing position. The engagement contact portion 32a of the elastic member 32 and the contact surface portion 31d of the latch 31 are separated from each other. After the latch 31 further rotates in the meshing direction from this state to the meshing position, the contact surface portion 31d of the latch 31 contacts the engagement contact portion 32a of the engagement elastic member 32, and the engagement elastic member 32 rotates together with the latch 31 in the meshing direction. The engagement elastic member 32 is formed of a material having a high elasticity such as rubber.

  As shown in FIGS. 1 to 4, the restraining return spring 33 is a torsion coil spring in which a coiled winding portion is inserted into the latch shaft member 30, and one end portion 33 a extending radially outward is engaged. The other end 33 b is engaged with the combined elastic member 32, and extends between the latch shaft member 30 and the engagement connecting piece 22 of the cover plate 20. As shown in FIGS. 1A and 1B, the restraining return spring 33 is formed before the engagement contact portion 32 a of the engagement elastic member 32 contacts the contact surface portion 31 d of the latch 31. In the state, the engagement contact portion 32 a contacts the engagement connection piece 22, thereby preventing the engagement elastic member 32 from rotating counterclockwise around the axis of the latch shaft member 30. Thereby, the restraint return spring 33 is in a no-load state regardless of the rotation position of the latch 31 when the engagement contact portion 32a of the engagement elastic member 32 is in a state before contacting the contact surface portion 31d of the latch 31. It becomes. On the other hand, when the latch 31 rotates in the meshing direction in a state where the engagement contact portion 32a of the engagement elastic member 32 is in contact with the contact surface portion 31d of the latch 31, FIG. 1 (d), the engagement elastic member 32 rotates clockwise around the axis of the latch shaft member 30 with the other end 33b of the restraining return spring 33 in contact with the engagement connecting piece 22. Rotate. Accordingly, the restraining return spring 33 acts to apply a rotational drag force against the engagement elastic member 32 when the engagement elastic member 32 rotates clockwise in FIG.

  Furthermore, as shown in FIGS. 1 to 4, the latch device includes a cam lever shaft 50 between the base plate 10 and the cover plate 20, and a spring control cam surface 31 e formed on the outer peripheral surface of the latch 31. It is.

  The cam lever shaft 50 is parallel to the latch shaft member 30 and the locking shaft member 40 at a position on the left side of the entry grooves 11 and 21 and the opening end side of the entry grooves 11 and 21 in FIG. The base plate 10 and the cover plate 20 are fixed. A cam lever 51 and a cam lever spring 52 are supported on the cam lever shaft 50.

  The cam lever 51 extends from the cam lever shaft 50 along the entrance grooves 11 and 21 toward the back end thereof, and is configured to be rotatable around the axis of the cam lever shaft 50 between the base plate 10 and the locking plate 41. It is arranged between them. The cam lever 51 is provided with an engaging protrusion 51a and a spring engaging piece 51b. The engagement protrusion 51 a and the spring engagement piece 51 b are provided so as to protrude from the surface of the cam lever 51 facing the cover plate 20 toward the cover plate 20. The engaging protrusion 51 a is a columnar portion formed at a protruding height smaller than the thickness of the locking plate 41. The engaging protrusion 51a is disposed on the edge of the cam lever 51 on the side separated from the entry grooves 11 and 21, and the cam lever 51 rotates in the clockwise direction in FIG. It is possible to press against the locking plate 41 so as to rotate counterclockwise. Here, as shown in FIG. 1, in a state where the engaging protrusion 51 a is in contact with the locking plate 41, the cam lever 51 is located on the side closer to the entry grooves 11 and 21 beyond the engaging claw portion 41 a of the locking plate 41. It does not protrude. The spring engagement piece 51b is a flat plate-like portion having a projecting height larger than that of the engagement protrusion 51a, and is disposed on the edge of the cam lever 51 on the side away from the entry grooves 11 and 21.

  The cam lever 51 is provided with a restraining cam surface 51 c at the tip edge located on the back side of the base plate 10. As shown in FIG. 1, the restraining cam surface 51 c has an arc shape that gradually increases as the distance from the axis of the cam lever shaft 50 goes counterclockwise. A portion of the restricting cam surface 51c adjacent to the entry grooves 11 and 21 is located at the striker contact portion 31c in the latch 31 when the cam lever 51 rotates clockwise in FIG. The size is such that it can enter the meshing groove 31a without abutting on the tip. On the other hand, the portion of the restraining cam surface 51c separated from the entry grooves 11, 21 can sequentially press the striker contact portion 31c of the latch 31 disposed at the meshing position to rotate the latch 31 in the meshing direction. Dimensions are formed.

  Further, the cam lever 51 moves from the position where the latch 31 is released when the engaging protrusion 51a is brought into contact with the locking plate 41 in a state where the restricting protrusion 41b of the locking plate 41 is in contact with the second stopper piece 15 of the base plate 10. While maintaining the state separated from the striker contact portion 31c of the latch 31 until the amount of rotation in the meshing direction exceeds a preset set angle, when the rotation of the latch 31 in the meshing direction reaches the set angle The abutting portion 31c of the latch 31 is pressed against the striker 31c, and rotates counterclockwise in FIG.

  1 to 4, the cam lever spring 52 is a torsion coil spring in which a coiled winding portion is inserted into the cam lever shaft 50, and one end portion 52 a extending radially outward is formed on the cam lever 51. 1 is engaged with the spring engaging piece 51b, and the other end 52b is engaged with the spring engaging part 25 provided on the cover plate 20, and the cam lever 51 is always pressed clockwise in FIG. doing.

  The spring control cam surface 31e is formed in a region where one end 43a of the return spring 43 abuts on the outer peripheral surface of the latch 31, and as shown in FIG. 5, the latch urging cam portion 31e1 and the centripetal cam portion 31e2. The latch biasing cam portion 31e1 is a portion that acts to rotate the latch 31 in the opening direction when pressed by one end 43a of the return spring 43. In the first embodiment, the latch 31 rotates in the meshing direction from the open position shown in FIG. 1A and reaches one end of the return spring 43 until reaching the state shown in FIG. It is formed in a region where 43a abuts. As shown in FIG. 5, the centripetal cam portion 31 e 2 has an arc shape centered on the axis of the latch shaft member 30, and the pressing force by one end 43 a of the return spring 43 is applied to the shaft of the latch shaft member 30. 1 is a portion that acts toward the heart, and the latch 31 further rotates in the meshing direction from the state shown in FIG. 1B, and after the meshing position shown in FIG. 1C, the restraint shown in FIG. It is formed in a region where one end 43a of the return spring 43 abuts until the state is reached.

  In the latch device configured as described above, as shown by a two-dot chain line in FIG. 6, the backrest portion SS of the vehicle seat S is rotated forward and overlapped with the seating portion SZ. 1 is not engaged with the striker ST, the cam lever 51 is rotated clockwise by the spring force of the cam lever spring 52, and the engagement protrusion 51a is in contact with the locking plate 41 as shown in FIG. is there. The locking plate 41 pressed by the cam lever 51 is rotated most counterclockwise in FIG. 1 together with the open lever 42 urged by the return spring 43 with the restricting projection 41b coming into contact with the second stopper piece 15 of the base plate 10. Retained. The latch 31 arranged in the open position is held in the open position with the hook portion 31b abutting against the first stopper piece 14 of the base plate 10, and the opening of the engagement groove 31a is formed in the entrance groove 11 formed in the base plate 10 and the cover plate 20. , 21 in accordance with the opening.

  In this state, one end 43a of the return spring 43 comes into contact with the latch urging cam portion 31e1 at a spring control cam surface 31e formed on the outer peripheral surface of the latch 31. Further, in the state shown in FIG. 1A, the striker contact portion 31 c of the latch 31 is in a state of being separated from both the locking plate 41 and the cam lever 51. Further, the restraining return spring 33 is not in a state of applying a spring force to the latch 31 because the engagement contact portion 32 a of the engagement elastic member 32 is separated from the contact surface portion 31 d of the latch 31. Accordingly, the latch 31 is maintained in a state in which the hook portion 31 b is pressed against the first stopper piece 14 only by the spring force from the one end portion 43 a of the return spring 43.

  As shown by the arrow in FIG. 6 from the above state, when the backrest portion SS is raised and moved close to the vehicle main body B, the striker ST gradually enters the entrance grooves 11 and 21 of the base plate 10 and the cover plate 20. Will do. When the striker ST enters the entry grooves 11 and 21, the striker ST contacts the striker contact portion 31 c of the latch 31, so that the latch 31 resists the spring force of the return spring 43 and the shaft of the latch shaft member 30. It rotates in the meshing direction around the heart. When the entry of the striker ST proceeds and the state shown in FIG. 1B is reached, the tip of the striker contact portion 31c comes into contact with the engagement claw portion 41a of the locking plate 41, and thereafter the engagement claw of the locking plate 41 The latch 31 rotates in the meshing direction against the spring force of the return spring 43 and the spring force of the cam lever spring 52 acting via the portion 41a. However, after the striker contact portion 31c of the latch 31 contacts the locking plate 41, one end portion 43a of the return spring 43 reaches the centripetal cam portion 31e2 of the spring control cam surface 31e. The force that presses the latch 31 in the opening direction through the one end 43a of the first member 43a does not act.

  When the latch 31 rotates just before the engagement position, the engagement contact portion 32a of the engagement elastic member 32 contacts the contact surface portion 31d of the latch 31, and thereafter the engagement elastic member 32 rotates in the engagement direction together with the latch 31. Therefore, the restraint return spring 33 engaged between the engagement elastic member 32 and the engagement connecting piece 22 of the cover plate 20 provides a rotational drag force against the rotation of the latch 31 in the meshing direction. Will act. When the contact surface portion 31d of the latch 31 contacts the engagement contact portion 32a of the engagement elastic member 32, the impact is buffered by the engagement elastic member 32, and abnormal noise is generated. There is no risk of damage to both sides.

  The approach of the striker ST further progresses, and the rotation of the latch 31 in the meshing direction proceeds against the spring force of the return spring 43, the spring force of the cam lever spring 52, and the spring force of the restraining return spring 33, and FIG. ), The opening of the entrance grooves 11 and 21 is closed by the hook portion 31b of the latch 31, and the locking plate 41 is rotated counterclockwise by the spring force of the return spring 43. 41a enters the engagement groove 31a of the latch 31 and engages with the striker contact portion 31c. In this state, the hook 31b of the latch 31 prevents the striker ST from moving in the direction deviating from the entry grooves 11, 21, and the engagement claw 41a engages to release the latch 31 in the opening direction. The rotation is restricted, and the backrest portion SS of the vehicle seat S is maintained in a state of rising from the rear end edge portion of the seating portion SZ.

  When the latch 31 is disposed at the meshing position, the cam lever 51 rotates clockwise in FIG. 1 against the spring force of the restraining return spring 33 by the spring force of the cam lever spring 52, and the restraining cam surface 51c is latched 31. By making sliding contact with the hook portion 31b, the latch 31 is shifted to a restrained state as shown in FIG. 1D, and the state is maintained. In the restrained state, the striker ST is sandwiched between the hook portion 31b of the latch 31 and the inner wall surface located on the back side of the entry grooves 11 and 21 in the base plate 10, and vibration is applied. There is no fear of causing problems such as abnormal noise.

  On the other hand, when the open lever 42 is rotated clockwise in FIG. 1 by operating an operation lever (not shown) in the restraint state shown in FIG. 1 (d), the locking plate 41 is rotated clockwise in conjunction with it. The cam lever 51 rotates counterclockwise in FIG. 1 when the locking plate 41 comes into contact with the engaging projection 51a immediately after that, and both the engaging claw portion 41a of the locking plate 41 and the cam lever 51 come into striker contact. It will deviate from the movement area of the part 31c. As a result, the latch 31 rotates in the opening direction by the spring force of the restraining return spring 33, and then rotates in the same direction by the spring force of the return spring 43 and the spring force of the cam lever spring 52. Return to the open position shown in a). As a result, the striker ST can be deviated from the entry grooves 11 and 21, and the backrest portion SS can be again overlapped with the seating portion SZ as indicated by a two-dot chain line in FIG. .

  FIG. 7 is a graph showing the relationship between the amount of rotation of the latch 31 and the rotational resistance against rotation in the meshing direction in the latch device described above. As shown in the figure, according to the latch device, a torsion coil spring is applied as the return spring 43, and the return spring is operated by the spring control cam surface 31e until the latch 31 is engaged from the open position. The rotational drag that resists the rotation in the meshing direction due to the pressing force from one end 43a of 43 is made substantially zero in the middle. For this reason, the engagement when the locking plate 41 is engaged with the latch 31 without causing a situation in which the rotational drag from the one end 43a of the return spring 43 increases according to the amount of rotation of the latch 31 in the engagement direction. It becomes possible to reduce the load and improve the operability. The retracted position described in FIG. 7 is a position where the latch 31 is in an intermediate state between FIG. 1C and FIG. 1D, and the cam lever spring 52 holds the latch 31 in FIG. This position is no longer acting in the counterclockwise direction.

  In addition, at the initial stage when the striker ST enters the entry grooves 11 and 21, the locking plate 41 and the cam lever 51 are separated from the striker contact portion 31 c of the latch 31. The rotation resistance is only due to the spring force of the return spring 43. As a result, the approach load of the striker ST with respect to the entry grooves 11 and 21 becomes extremely small, and the operability can be further improved.

  Furthermore, in the latch device of the first embodiment described above, the restraint return spring 33 is applied to the latch 31 only before the engagement position until the restraint state is reached, and the rotation starts from the open position in the engagement direction. Even in this case, the rotational drag due to the spring force of the restraining return spring 33 does not act on the latch 31 until just before the meshing position. In addition, the spring force of the restraining return spring 33 is sufficient to rotate the latch 31 in the opening direction from the restraining state so that the meshing position is slightly passed. As a result, the cam lever spring 52 for shifting the latch 31 from the meshing position to the restrained state via the cam lever 51 may have a slightly larger spring force than the restraining return spring 33, and the restraining return spring 33 as described above. As the spring force can be reduced, it is possible to apply a spring having a small spring force, and the meshing load from the open position of the latch 31 to the retracted position can be greatly reduced.

  Further, according to the above-described latch device, the restraint return spring 33 is made to act on the latch 31 only from the time immediately before the meshing position to the restraint state. Therefore, as shown in FIG. Accordingly, the release operation load of the latch device, that is, the operation load when the open lever 42 is rotated clockwise in FIG. 1 can be reduced, which is extremely advantageous in terms of release operability.

(Embodiment 2)
9 and 10 show a latch device according to the second embodiment of the present invention. As in the first embodiment, the latch device exemplified here applies to the vehicle seat S shown in FIG. 6, and engages the striker ST provided in the vehicle main body B so that the backrest SS is attached to the vehicle main body B. The first embodiment is different from the first embodiment in that the configuration of the spring control cam surface provided on the latch is different from that of the first embodiment, and there is no configuration corresponding to the engaging member and the restraining return spring. 1 and different. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed descriptions thereof are omitted.

  As shown in FIGS. 9 and 10, in the latch device of the second embodiment, the spring control cam surface 131e formed on the outer peripheral surface of the latch 131 has a latch urging cam portion 131e1 and a centripetal cam portion 131e2. ing. The latch urging cam portion 131e1 is a portion that acts to rotate the latch 131 in the opening direction when pressed by one end portion 43a of the return spring 43 provided on the locking shaft member 40. In the second embodiment, the latch 131 rotates in the meshing direction from the open position shown in FIG. 9A and reaches one end of the return spring 43 until reaching the restrained state shown in FIG. 9D. It is formed in a region where the portion 43a abuts. The centripetal cam portion 131 e 2 has an arc shape centered on the axis of the latch shaft member 30, and is a portion that applies the pressing force by one end 43 a of the return spring 43 toward the axis of the latch shaft member 30. 9b, that is, only a very short section is formed in a substantially intermediate portion between the open position shown in FIG. 9 (a) and the meshing position shown in FIG. 9 (c). It is.

  As described above, the latch device of the second embodiment is not provided with a configuration corresponding to the engagement elastic member 32 and the restraining return spring 33 of the first embodiment. Other configurations are the same as those in the first embodiment.

  In the latch device configured as described above, when the latch 131 is not engaged with the striker ST, the cam lever 51 is rotated clockwise by the spring force of the cam lever spring 52 as shown in FIG. The protrusion 51 a is in contact with the locking plate 41. The locking plate 41 pressed by the cam lever 51 is in a state in which the restricting projection 41b contacts the second stopper piece 15 of the base plate 10 and rotates most counterclockwise in FIG. 9 together with the open lever 42 biased by the return spring 43. Retained. The latch 131 disposed in the open position is held in the open position with the hook portion 131b abutting against the first stopper piece 14 of the base plate 10, and the opening of the engagement groove 131a is formed in the entrance groove 11 formed in the base plate 10 and the cover plate 20. , 21 in accordance with the opening.

  In this state, one end 43a of the return spring 43 comes into contact with the latch urging cam portion 131e1 at a spring control cam surface 131e formed on the outer peripheral surface of the latch 131. In the state shown in FIG. 9A, the striker contact portion 131 c of the latch 131 is in a state of being separated from both the locking plate 41 and the cam lever 51. Accordingly, the latch 131 is maintained in a state in which the hook portion 131 b is pressed against the first stopper piece 14 only by the spring force of the return spring 43.

  When the striker ST gradually enters the entry grooves 11 and 21 of the base plate 10 and the cover plate 20 from the above-described state, the striker ST comes into contact with the striker contact portion 131c of the latch 131, so that the spring force of the return spring 43 is increased. Accordingly, the latch 131 rotates about the axis of the latch shaft member 30 in the meshing direction. When the entry of the striker ST proceeds and the state shown in FIG. 9B is reached, the tip of the striker contact portion 131c comes into contact with the engagement claw portion 41a of the locking plate 41, and thereafter the engagement claw of the locking plate 41 The latch 131 rotates in the meshing direction against the spring force of the return spring 43 and the spring force of the cam lever spring 52 acting via the portion 41a. However, when the striker contact portion 131c of the latch 131 contacts the locking plate 41, one end portion 43a of the return spring 43 contacts the centripetal cam portion 131e2 of the spring control cam surface 131e. The force that presses the latch 131 in the opening direction through one end 43a of the 43 does not act.

  When the striker ST further advances and the latch 131 rotates in the meshing direction against the spring force of the return spring 43 and the cam lever spring 52, the meshing position shown in FIG. The openings of the entrance grooves 11 and 21 are closed by the hook portion 131 b of the latch 131, the locking plate 41 is rotated counterclockwise by the spring force of the return spring 43, and the engagement claw portion 41 a is engaged with the engagement groove 131 a of the latch 131. And enters the striker contact portion 131c. In this state, the hook 131b of the latch 131 prevents the striker ST from moving in a direction deviating from the entry grooves 11 and 21, and the engagement claw 41a engages to release the latch 131 in the opening direction. The rotation is restricted, and the striker ST and the latch 131 are maintained in a meshed state.

  Here, in the meshing position shown in FIG. 9C, the rotational drag applied to the latch 131 from the engaging claw portion 41a of the locking plate 41 becomes zero as described above. However, during the above-described operation, the portion where one end 43a of the return spring 43 abuts is latched from the centripetal cam portion 131e2 on the spring control cam surface 131e after passing through the state shown in FIG. After the transition to the urging cam portion 131e1, until one of the end portions 43a of the return spring 43 reaches the restrained state shown in FIG. It will abut. Therefore, from the state immediately before reaching the meshing position, the rotational resistance acts on the latch 131 only by the pressing force applied from one end 43a of the return spring 43.

  As a result, as shown in FIG. 9 (e), the locking plate 41 is rotated clockwise in FIG. 9 by operating the open lever 42 from the restrained state, and further, as shown in FIG. 9 (f). When the cam lever 51 is rotated counterclockwise in FIG. 9 via the mating protrusion 51a, the latch 131 causes the one end portion 43a of the return spring 43 to abut the latch biasing cam portion 131e1 on the spring control cam surface 131e. Rotate in the opening direction, and finally return to the opening position shown in FIG.

  According to the above latch device, a torsion coil spring is applied as the return spring 43, and one end portion 43a of the return spring 43 is operated by the action of the spring control cam surface 131e until the latch 131 is engaged from the open position. The rotational drag that resists the rotation in the meshing direction due to the pressing force from the shaft is made substantially zero in the middle. For this reason, there is no situation in which the rotational drag from one end 43a of the return spring 43 increases in accordance with the amount of rotation of the latch 131 in the meshing direction. It becomes possible to reduce the load and improve the operability.

  In addition, when the striker ST enters the entrance grooves 11 and 21, the locking plate 41 and the cam lever 51 are configured to be separated from the striker contact portion 131 c of the latch 131, and thus act on the latch 131. The rotation resistance is only due to the spring force of the return spring 43. As a result, the approach load of the striker ST with respect to the entrance grooves 11 and 21 becomes extremely low, and the operability can be further improved.

  Furthermore, in the latch device according to the second embodiment described above, the return spring 43 is again applied to the latch 131 from just before the meshing position to the restraint state, so that the restraint state is maintained as it is from the open position. It is possible to set the spring force of the return spring 43 in a restrained state to be smaller than in the case where it is acted on until. As a result, the cam lever spring 52 for shifting the latch 31 from the meshing position to the restrained state via the cam lever 51 may have a slightly larger spring force than the restraining return spring 33, and the restraining return spring 33 as described above. As the spring force can be reduced, it is possible to apply a spring having a small spring force, and the meshing load from the open position of the latch 31 to the retracted position can be greatly reduced.

  In the second embodiment, since the functions corresponding to the engagement elastic member 32 and the restraining return spring 33 shown in the first embodiment are not provided, the number of parts can be reduced.

(Embodiment 3)
11 and 12 show a latch device according to Embodiment 3 of the present invention. As in the first embodiment, the latch device exemplified here applies to the vehicle seat S shown in FIG. 6, and engages the striker ST provided in the vehicle main body B so that the backrest SS is attached to the vehicle main body B. This is for detachably fixing, and differs from the first embodiment in that there is no configuration corresponding to the engaging member and the restraining return spring. It differs from Embodiment 1 by the point provided with. In the third embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed descriptions thereof are omitted.

  As shown in FIG. 11, in the latch device of the third embodiment, the rocking shaft member 40 is provided with an idle lever 60. The idling lever 60 is a flat plate member that extends from the axial center of the locking shaft member 40 in a manner that intersects with the extension line of the entrance grooves 11 and 21, and includes a pressing protrusion 61 at the extending end. . The pressing protrusion 61 is a columnar member protruding from the extending end of the idle swing lever 60, and contacts the spring control cam surface 31 e of the latch 31 when the idle lever 60 rotates clockwise in FIG. 11. Can be rotated in the opening direction. While the idle swing lever 60 and the open lever 42 are in contact with each other, a minimum included angle is set, and the idle lever 60 and the open lever 42 can relatively rotate in a direction in which the included angle is expanded.

  The lever spring 70 is a torsion coil spring in which a coiled winding portion is inserted into the latch shaft member 30, and one end portion 70 a extending radially outward is engaged with the pressing protrusion 61 of the idle swing lever 60, and The other end portion 70b extending in the radially outward direction is engaged with a spring engaging portion 41d provided on the restricting projection 41b of the open lever 42, so that the idle swing lever 60 and the open lever 42 have a minimum included angle. Both are energized.

  As described above, the latch device of the third embodiment is not provided with a configuration corresponding to the engagement elastic member 32 and the restraining return spring 33 of the first embodiment. Other configurations are the same as those in the first embodiment.

  In the latch device configured as described above, when the latch 31 is not engaged with the striker ST, the cam lever 51 rotates clockwise by the spring force of the cam lever spring 52 as shown in FIG. The protrusion 51 a is in contact with the locking plate 41. The locking plate 41 pressed by the cam lever 51 abuts against the second stopper piece 15 of the base plate 10 via the lever spring 70 and rotates most counterclockwise in FIG. 11 together with the open lever 42 biased by the return spring 43. Kept in a state. The latch 31 arranged in the open position is held in the open position with the hook portion 31b abutting against the first stopper piece 14 of the base plate 10, and the opening of the engagement groove 31a is formed in the entrance groove 11 formed in the base plate 10 and the cover plate 20. , 21 in accordance with the opening.

  In this state, one end 43a of the return spring 43 comes into contact with the latch urging cam portion 31e1 at a spring control cam surface 31e formed on the outer peripheral surface of the latch 31. Further, in the state shown in FIG. 11H, the striker contact portion 31 c of the latch 31 is in a state of being separated from both the locking plate 41 and the cam lever 51. Therefore, the latch 31 is maintained in a state in which the hook portion 31 b is pressed against the first stopper piece 14 only by the spring force of the return spring 43.

  When the striker ST gradually enters the entry grooves 11 and 21 of the base plate 10 and the cover plate 20 from the above-described state, the striker ST comes into contact with the striker contact portion 31 c of the latch 31, thereby increasing the spring force of the return spring 43. Accordingly, the latch 31 rotates in the meshing direction around the axis of the latch shaft member 30. When the entry of the striker ST proceeds and the state shown in FIG. 11G is reached, the tip of the striker contact portion 31c comes into contact with the engagement claw portion 41a of the locking plate 41, and thereafter the engagement claw of the locking plate 41 The latch 31 rotates in the meshing direction against the spring force of the return spring 43 and the spring force of the cam lever spring 52 acting via the portion 41a. However, when the striker contact portion 31c of the latch 31 contacts the locking plate 41, one end portion 43a of the return spring 43 contacts the centripetal cam portion 31e2 of the spring control cam surface 31e. The force which presses the latch 31 in the opening direction via one end 43a of 43 does not act.

  When the striker ST further advances and the rotation of the latch 31 proceeds in the meshing direction against the spring force of the return spring 43 and the cam lever spring 52 and the meshing position shown in FIG. 31, the opening of the entrance grooves 11, 21 is closed, and the locking plate 41 is rotated counterclockwise by the spring force of the return spring 43 so that the engaging claw portion 41a is engaged with the engagement groove 31a of the latch 31. It enters and engages with the striker contact part 31c. In this state, the hook 31b of the latch 31 prevents the striker ST from moving in the direction deviating from the entry grooves 11, 21, and the engagement claw 41a engages to release the latch 31 in the opening direction. The rotation is restricted, and the striker ST and the latch 31 are maintained in a meshed state.

  Here, at the meshing position shown in FIG. 11 (f), as described above, the rotational drag applied to the latch 31 from the engaging claw portion 41a of the locking plate 41 becomes zero. On the other hand, the rotational drag force when rotating in the meshing direction does not act at all until the restraint state shown in FIG.

  On the other hand, when the open lever 42 is rotated clockwise in FIG. 11 by operating an operation lever (not shown) in the restraint state shown in FIG. 11A, the idle swing lever 60 is moved in FIG. 11 by the spring force of the lever spring 70. , The pressing protrusion 61 of the idle swing lever 60 comes into contact with the spring control cam surface 31e of the latch 31, as shown in FIG.

  Thereafter, as shown in FIG. 11 (c), the locking plate 41 abuts on the engaging protrusion 51a of the cam lever 51, whereby the cam lever 51 rotates counterclockwise in FIG. 11, and shown in FIG. 11 (d). Thus, when the striker contact portion 31c of the latch 31 deviates from the restraining cam surface 51c of the cam lever 51, the latch 31 rotates in the opening direction by the spring force of the lever spring 70 as shown in FIG. Therefore, it returns to the open position shown in FIG.

  According to the latch device, a torsion coil spring is applied as the return spring 43, and one end portion 43a of the return spring 43 is applied by the action of the spring control cam surface 31e until the latch 31 is engaged from the open position. The rotational drag that resists the rotation in the meshing direction due to the pressing force from the shaft is made substantially zero in the middle. For this reason, the engagement when the locking plate 41 is engaged with the latch 31 without causing a situation in which the rotational drag from the one end 43a of the return spring 43 increases according to the amount of rotation of the latch 31 in the engagement direction. It becomes possible to reduce the load and improve the operability.

  In addition, at the initial stage when the striker ST enters the entry grooves 11 and 21, the locking plate 41 and the cam lever 51 are separated from the striker contact portion 31 c of the latch 31. The rotation resistance is only due to the spring force of the return spring 43. As a result, the approach load of the striker ST with respect to the entrance grooves 11 and 21 becomes extremely low, and the operability can be further improved.

  Further, in the above-described latch device of the third embodiment, no rotational drag acts on the latch 31 in the meshing direction immediately before the meshing position until the restraint state is reached. As a result, the cam lever spring 52 for shifting the latch 31 from the meshing position to the restrained state via the cam lever 51 may have a slightly larger spring force than the restraining return spring 33, and the restraining return spring 33 as described above. As the spring force can be reduced, it is possible to apply a spring having a small spring force, and the meshing load from the open position of the latch 31 to the retracted position can be greatly reduced.

31 Latch 31a Engagement groove 31e Spring control cam surface 31e1 Latch urging cam portion 31e2 Centric cam portion 41 Locking plate 43 Return spring 43a, 43b End portion 131 Latch 131a Engagement groove 131e Spring control cam surface 131e1 Latch urging cam portion 131e2 direction Heart cam part ST striker

Claims (4)

When the striker enters the engagement groove of the latch, the latch is rotated in the engagement direction against the spring force of the return spring from the open position, and the latch is released by engaging the locking plate with the latch rotated to the predetermined engagement position. In a latch device that restricts rotation in the direction and holds the striker and the latch in an engaged state,
The return spring is a torsion coil spring that acts on the latch against the rotation in the meshing direction by pressing the peripheral surface of the latch through one end,
On the peripheral surface of the latch, a spring control cam surface that reduces a rotational drag force by a return spring after the striker enters and before the latch rotates in the meshing direction and reaches the meshing position is formed ,
Furthermore, after the latch is rotated to the meshing position, a cam lever is provided that further rotates the latch in the meshing direction by the spring force of the cam lever spring to shift the striker to a restrained state. A latch device, wherein a cam lever presses a peripheral surface of a latch by a spring force of a spring, and a rotational drag force against rotation in a meshing direction is applied to the latch.   When the cam lever is separated from the peripheral surface of the latch and exceeds the set angle before the rotation amount of the latch exceeds a preset set angle after the latch rotates in the meshing direction due to the entry of the striker The latch device according to claim 1, wherein a peripheral surface of the latch is pressed.   The return spring presses the peripheral surface of the latch through the locking plate after the striker enters the latch and reaches the meshing position, thereby providing rotational resistance against rotation in the meshing direction against the latch. Is to act,
  The spring control cam surface acts so that the pressing force of the latch by one end of the return spring is directed toward the center of rotation of the latch after the rotational drag to the latch by the locking plate is applied and until it becomes a restrained state. Having a centripetal cam section,
  The latch is provided with a torsion coil spring that is separate from the return spring, and is provided with a constrained return spring that acts against a rotational drag force that is resisted at least during the transition from the meshing position to the constrained state. The latch device according to claim 1.   The return spring presses the peripheral surface of the latch through the locking plate after the striker enters the latch and reaches the meshing position, thereby providing rotational resistance against rotation in the meshing direction against the latch. Is to act,
  The spring control cam surface acts so that the pressing force of the latch by one end of the return spring is directed toward the center of rotation of the latch after the rotational drag to the latch by the locking plate is applied and until it becomes a restrained state. Having a centripetal cam section,
  Further, when the cam lever moves in the restraint release direction from the latch in the restrained state and the engagement state with the locking plate is released, the cam lever is brought into contact with the latch in conjunction with the engagement release movement of the locking plate. The latch device according to claim 1, further comprising an idle lever that rotates the lever in an opening direction.

Images