CA3032700C - Lock and screen door - Google Patents

Abstract

A lock, comprising: a cam (21, 22), capable of rotating between at least a first position and a second position and having engaging portion for an engaging member to be locked; a locking part, capable of locking the cam (21, 22) so as to make the cam (21, 22) unable to rotate; and a trigger part. When the cam (21, 22) rotates to the second position, the trigger part is triggered, so that the locking part is operated to lock; when the cam (21, 22) rotates to a position other than the second position, the trigger part will no longer be triggered, so that the locking part is operated to unlock. When the cam (21, 22) is in the first position, the member to be locked can disengage from the engaging portion and can engage with the engaging portion; when the member to be locked engages with the engaging portion and the cam (21, 22) rotates to the second position, the member to be locked cannot disengage from the engaging portion. Further disclosed is a screen door comprising the lock.

Description

CA Phase of PCT/CN2017/112029 Our Ref.: 37761-18 Appl. No. 3,032,700 (2043-160645CA) SPECIFICATION
TITLE
LOCK AND SCREEN DOOR
CROSS-REFERENCE TO RELATED APPLICATION
The present application is based upon and claims the benefit of a priority of Chinese Patent Application No. 201611208952.8, filed on December 23, 2016, with the tile of "LOCK
AND SCREEN DOOR".
TECHNICAL FIELD
The present disclosure relates to a lock and a screen door using the same.
BACKGROUND
The screen door in the existing subway platform usually uses an electromagnetic lock that locks and unlocks the door by inserting and drawing out a lock pin. Although such electromagnetic lock can hold the screen door in a closed position when needed, it still has the following disadvantages:
a. The electromagnetic lock in prior art is complicated in structure and usually has a symmetrical structure, which causes high difficulty in processing, assembly, and construction of the lock, as well as high difficulty in replacement and repair;
b. The electromagnetic lock in prior art has low working accuracy, which is prone to mishandling; and, c. The electromagnetic lock in prior art may generate during the operation more metal debris that is difficult to remove and easily leads to failure of the electromagnetic lock.
SUMMARY
Based on the foregoing deficiencies in prior art, the present disclosure intends to provide a lock which is capable of relieving at least one of the afore-mentioned technical problems and a screen door using the same.
In order to achieve this object, the present disclosure may use the technical solutions described below.
The present disclosure provides a lock comprising: a cam capable of rotating at least between a first position and a second position, and having an engaging portion for engaging with a member to be locked; a locking assembly capable of locking the cam so as to make the =

CA Phase of PCT/CN2017/112029 Our Ref.: 37761-18 (2043-160645CA) cam unable to rotate; and a trigger assembly which is triggered so that the locking assembly locks the cam when the cam rotates to the second position, and which is no longer triggered so that the locking assembly unlocks the cam when the cam rotates to a position other than the second position, wherein, when the cam is in the first position, the member is able to disengage from the engaging portion and is able to engage with the engaging portion, and when the member engages with the engaging portion and the cam rotates to the second position, the member is unable to disengage from the engaging portion.
Preferably, the engaging portion comprises a cutout provided in a periphery of the cam, and a recessed portion recessed toward a radial inner side of the cam relative to the cutout and toward an upstream side of a rotation direction of the cam from the first position toward the second position.
Preferably, the trigger assembly comprises a mechanical switch which is pressed by a triggering portion formed at an outer periphery of the cam to trigger the trigger assembly when the cam rotates to the second position.
More preferably, the mechanical switch is an inching switch.
More preferably, the triggering portion includes a small diameter portion, a large diameter portion, and a connecting portion connecting the small diameter portion and the large diameter portion, the maximum distance from an outer circumferential surface of the small diameter portion to a rotation center of the cam is smaller than the minimum distance from the outer circumferential surface of the mechanical switch to the rotation center of the cam, and the maximum distance from an outer circumferential surface of the large diameter portion to the rotation center of the cam is greater than the minimum distance from the outer circumferential surface of the mechanical switch to the rotation center of the cam.
Preferably, the locking assembly includes an armature and an electromagnetic coil, the armature is capable of advancing and retreating by an effect of the electromagnetic coil, the electromagnetic coil is powered off when the trigger assembly is triggered, and is powered on when the trigger assembly is no longer triggered and when the lock is to be unlocked, when the electromagnetic coil is powered off, the armature falls down to lock the cam, and when the electromagnetic coil is powered on, the armature is lifted up to unlock the cam.
More preferably, the cam further comprises a first step portion formed by forming a periphery of the cam into a stepped structure, when the electromagnetic coil is powered off, the armature falls down to abut against the first step portion, thereby locking the cam.
More preferably, the first step portion includes a first face which is parallel to a central axis of the armature when the cam is in the second position, and a second face perpendicular to the first face and parallel to an end face of the armature, when the electromagnetic coil is

2 CA Phase of PCT/CN2017/112029 Our Ref.: 37761-18 (2043-160645CA) powered off, the armature falls down to a position where the armature abutting against the first face and the second face.
More preferably, the cam further comprises a second step portion formed by forming the periphery of the cam into a stepped structure, the second step portion being formed at an upstream side of the first step portion in a rotation , direction of the cam from the second position toward the first position, the second step portion abuts against the armature when the cam rotates to the first step position.
Preferably, the cam includes a first cam and a second cam, and the trigger assembly includes a first trigger assembly configured for the first cam and a second trigger assembly configured for the second cam.
More preferably, the first cam and the second cam are configured to be symmetrical with respect to an central axis of the armature, when the electromagnetic coil is powered off, the armature falls down into a space defined by the first face and the second face of the first cam and the first face and the second face of the second cam, so as to simultaneously lock the first cam and the second cam.
Further provided in the present disclosure is a screen door comprising the lock according to any one of the afore-described technical solutions and a door body capable of sliding between an open position and a closed position, the member being secured to the door body, wherein when the door body is in the open position, the cam is in the first position; when the door body is in the closed position, the cam is in the second position; during the sliding of the door body from the open position toward the closed position, the member engages with the engaging portion of the cam, and then the member makes the cam to rotate from the first position to the a second position, and during the sliding of the door body from the closed position toward the open position, the locking assembly unlocks the cam, and then the member makes the cam to rotate from the second position to the first position to disengage from the cam.
Instead of the lock pin, the lock of the present disclosure comprises the cam, the trigger assembly, and the locking assembly, thereby simplifying the structure and lowering the possibility of failure and mishandling.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 a is a perspective schematic diagram of a lock according to an embodiment of the present disclosure; Fig. lb is a planar schematic diagram of the lock shown in Fig. la; Fig. lc is a further planar schematic diagram of the lock shown in Fig. la.
Fig. 2 is an amplified schematic diagram of a left cam of the lock shown in Fig. lb.

3 CA Phase of PCT/CN2017/112029 Our Ref.: 37761-18 (2043-160645CA) Fig. 3a and Fig. 3b are schematic illustrating diagrams of operation states of the lock shown in Fig. la, with partial structure of the lock omitted.
DETAILED DESCRIPTION
Embodiments of the present disclosure will be described below with reference to the drawings. "L" in the drawings indicates the longitudinal direction of a door body; "H"
indicates the height direction of the door body. In addition, the following description of the present disclosure will be made by taking the lock of the present disclosure used in a dimidiate door as an example.
In the present disclosure, "open position" and "closed position" of a pair of door bodies of the dimidiate door respectively refer to a position where the pair of door bodies has the maximum distance therebetween and a position where the pair of door bodies abuts against each other. When the pair of door bodies slides between the "open position"
and the "closed position", it means that the pair of door bodies is in an "intermediate position".
In the present disclosure, "locked position" and "unlocked position" of the cam respectively refer to the position of the cam when the entire lock locks the door (i.e., the lock is in a locked state) and the position of the cam when the entire lock unlocks the door bodies (i.e., the lock is in an unlocked state).
In the present disclosure, with regard to the left cam, "clockwise direction"
refers to the direction in which the left cam as shown in Figs. lb, lc, 3a, and 3b rotates from the locked position toward the unlocked position; "counterclockwise direction" is a direction opposite to "clockwise direction".
In the present disclosure, unless otherwise specified, "left", "right", "upper" and "lower"
indicating orientations respectively refer to the left side, the right side, the upper side, and the lower side as shown in Figs. lb, lc, 3a and 3b.
(Structure of the lock) As shown in Figs. la to lc, the lock according to an embodiment of the present disclosure comprises a lock bracket 1, a left cam 21 and a right cam 22, a trigger assembly (a left inching switch (micro switch) 31 and a right inching switch 32), a locking assembly (an armature 41 and an electromagnetic coil 42), a manual unlocking lever 5, and a spacing buffer 6. In the present embodiment, the lock bracket 1 is used to support other components of the lock and may be fixed to a door frame by, for example, a threaded connection. In the dimidiate door, the door frame is used to mount and house a pair of door bodies (not shown) of the dimidiate door freely slidable between the open position and the closed position. It should be noted that the present disclosure does not limit the shape and material of the lock bracket 1, the manner of

4 CA Phase of PCT/CN2017/112029 Our Ref.: 37761-13 (2043-160645CA) fixing the lock bracket 1 to the door frame, etc.
In the present embodiment, the left cam 21 and the right cam 22 are rotatably provided on the lock bracket 1 by means of bolts. gaskets are provided between heads of the bolts and the left and right cams 21, 22. It should be noted that the bolt herein is exemplary, and the present .. disclosure does not limit the manner in which the left cam 21 and the right cam 22 are provided on the lock bracket 1. The left cam 21 and the right cam 22 are located at a central position of the entire dimidiate door in the longitudinal direction L and are disposed at an upper position of the pair of door bodies of the dimidiate door in the height direction H.
The left cam 21 and the right cam 22 are symmetrical with respect to the center line of the dimidiate door in the longitudinal direction L, and are spaced apart from each other in the longitudinal direction L. The left cam 21 is used for engaging with and disengaging from a left door hook 71 fixed to a left door body of the pair of door bodies of the dimidiate door. The right cam 22 is used for engaging with and disengaging from a right door hook 72 fixed to a right door body of the pair of door bodies of the dimidiate door. When engaged with the .. corresponding door hook, the left cam 21 and the right cam 22 are rotatable as the pair of door bodies slides between the open position and the closed position. The left cam 21 and the right cam 22 rotate in opposite directions as they respectively rotate as the left and the right door bodies slide. The left door hook 71 and the right door hook 72 have the same structure and have an L shape as shown in Fig. la, with a long arm fixed to the door body and a short arm engaging with the cam. As an example, a hole is formed in an end portion of the long arm, into which a bolt is inserted to form the short arm. It should be noted that the present disclosure does not limit the door hook as explained above. The door hook may adopt any suitable shape, structure, etc.
The left cam 21 and the right cam 22 have a substantially circular basic shape. The left cam 21 and the right cam 22 further have a structure for cooperation with the trigger assembly, the locking assembly, and the door hook.
As shown in Fig. 2, the left cam 21 is provided with an engaging portion 211 for engaging with the left door hook 71. The engaging portion 211 includes a cutout provided in a periphery of the left cam 21 and a recessed portion communicating with the cutout, the recessed portion being recessed from the cutout toward a radially inner side of the left cam 21 and recessed toward an upstream side in a counterclockwise direction.
When the left cam 21 is in the unlocked position (a first position, see Fig.
3b), the cutout of the engaging portion 211 faces the left door hook 71 and is aligned to the left door hook 71 in the height direction H. When the left door body slides from the open position toward the closed position to move the left door hook 71 to a predetermined intermediate position, the left

5 = CA 03032700 2019-02-01 CA Phase of PCT/CN2017/112029 Our Ref.: 37761-18 (2043-160645CA) door hook 71 enters the cutout of the engaging portion 211. As the left door body slides further, the left door hook 71 abuts against the left cam 21 to push the left cam 21 to rotate in counterclockwise direction. Subsequently, the left door hook 71 enters the recessed portion of the engaging portion 211, so that the left cam 21 is in the locked position (a second position, see Figure 3a). In contrast, when the left door body slides from the closed position toward the open position, the left door hook 71 drives the left cam 21 to rotate in clockwise direction, and is disengaged from the engaging portion 211 when the left cam 21 rotates to a prescribed position.
In order to enable the left door hook 71 to easily pass through the cutout, the width of the cutout in the height direction H is greater than the width of the short arm of the left door hook 71 in the height direction H. Moreover, in order to reliably hold the left door hook 71 in the recessed portion of the engagement portion 211, the depth D of the recessed portion with respect to the side face of the cutout on the downstream side in the clockwise direction is greater than the radius of the short arm of the left door hook 71. Preferably, the side face of the cutout on the downstream side in the clockwise direction is a flat surface which is parallel to the plane in which the motion path of the left door hook 71 is located when the left cam 21 is in the unlocked position, and comes into contact with the left door hook 71 early during the left door hook 71 entering into the engagement portion 211, so as to guide the motion of the left door hook 71. In addition, the size of the engaging portion 211 should not be too large:
otherwise the overall rigidity of the left cam 21 may be affected. However, it should be noted that the present disclosure does not limit the shape of the engaging portion 211 as long as the above function can be performed by the engagement between the engagement portion 211 and the left door hook 71. The manner in which the cam and the door hook are engaged is not limited.
In addition, as shown in Fig. 2, the left cam 21 is further provided with a first step portion 212 which is formed by forming a periphery of the left cam 21 into a stepped structure. When the left cam 21 rotates to the locked position as shown in Fig. 3a, the first face 2121 of the first step portion 212 is parallel to the central axis of the armature 41 of the locking assembly; the second face 2122 of the first step portion 212 is perpendicular to the first face 2121 and is parallel to the lower end surface of the armature 41. Similarly, the right cam 22 has a first step portion 222. A distance in the longitudinal direction L between the first face 2121 of the first step portion 212 of the left cam 21 and the first face 2221 of the first step portion 222 of the right cam 22 is substantially equal to the width of the armature 41 in the longitudinal direction L. A distance between the right end portion of the second face 2122 of the step portion 212 and the left end portion of the second face 2222 of the first step portion 222 in the longitudinal

6 CA Phase of PCT/CN2017/112029 Our Ref.: 37761-13 (2043-160645CA) direction L is smaller than the width of the armature 41 in the longitudinal direction L. As shown in Fig. 3a, when the lock needs to be locked, the armature 41 of the locking assembly descends and abuts tightly against the first and second faces of the first step portion 212 and the first step portion 222, thereby locking the cams so that the cams cannot rotate, and functioning to hold the pair of door bodies in the closed position, i.e., locking the door bodies in the closed position.
It should be noted that the present disclosure does not limit the shape of the first step portions 212, 222 as long as the first step portions cooperate with the armature 41 to lock the cams so that the cams cannot rotate.
Further, as shown in Fig. 2, the left cam 21 is further provided with a triggering portion 213. The triggering portion 213 includes a small diameter portion 2131, a large diameter portion 2132, and a smooth inclined surface 2133 that connects the small diameter portion 2131 with the large diameter portion 2132. The maximum distance from the outer circumferential surface of the small diameter portion 2131 to the rotation center of the left cam 21 is smaller than the minimum distance from the outer circumferential surface of the 1eft inching switch 31 to the rotation center of the left cam 21. That is to say, during the rotation of the cam, the small diameter portion 2131 will be in contact with and apply a force to the left inching switch 31, but will not cause the movable contact of the left inching switch 31 to connect with the fixed contact, and the left inching switch 31 remains disconnected. The maximum distance from the outer circumferential surface of the large diameter portion 2132 to the rotation center of the left cam 21 is greater than the minimum distance from the outer circumferential surface of the left inching switch 31 to the rotation center of the left cam 21. In other words, when the left inching switch 31 and the large diameter portion 2132 face each other in the radial direction of the left cam 21, the large diameter portion 2132 applies a force to the left inching switch 31 so that the movable contact is connected with the fixed contact of the left inching switch 31, thereby the left inching switch 31 turning into a turn-on state. In order not to hinder the rotation of the cam, the inclined surface 2133 is preferably inclined at an angle of less than 45 degrees with respect to the direction in which a tangent at the joint of the inclined surface 2133 and the small diameter portion 2131 extends. On the other hand, considering the size of the cam and shortening the time of turning on the left inching switch, the angle formed by the inclined surface 2133 with respect to the direction in which the tangent at the joint of the inclined surface 2133 and the small diameter portion 2131 extends should not be too small.
In the present embodiment, when the left cam 21 rotates to the locked position as the left door body slides, the large diameter portion 2132 comes into contact with the left inching

7 CA Phase of PCT/CN2017/112029 Our Ref.: 37761-18 (2043-160645CA) switch 31 to turn on the left inching switch 31; when the left cam 21 leaves the locked position as the left door body slides, the large diameter portion 2132 rotates away from the left inching switch 31, and the left inching switch 31 switches from the turn-on state to a turn-off state.
The left cam 21 further includes a second step portion 214 which is also formed by forming a periphery of the left cam 21 into a stepped structure. The second step portion 214 is formed on the upstream side in the clockwise direction of the first step portion 212. Similarly, the right cam 22 has a second step portion 224. When the left cam 21 is in the unlocked position, a portion of the armature 41 in a lifted state is located between the second step portion 214 of the left cam 21 and the second step portion 224 of the right cam 22, and a portion of the second step portion 214 of the left cam 21 and a portion of the second step portion 224 of the right cam 22 abut against the armature 41 to prevent the left cam 21 and the right cam 22 from continuing to rotate.
The left cam 21 further comprises a stopper portion 215. The stopper portion 215 is formed on the upstream side in the clockwise direction of the triggering portion 213. Similar to the triggering portion 213, the stopper portion 215 has a small diameter portion 2151, a large diameter portion 2152, and an inclined surface 2153 that connects the small diameter portion 2151 and the large diameter portion 2152. The distances from the outer circumferential surface of the small diameter portion 2151 and the large diameter portion 2152 to the rotation center of the left cam 21 are respectively set similarly to the small diameter portion 2131 and the large diameter portion 2132. Further, the angle formed by the inclined surface 2153 with respect to the direction in which a tangent at the joint of the inclined surface 2153 and the small diameter portion 2151 extends is greater than 45 degrees. When the left cam 21 is in the unlocked position, the inclined surface 2153 abuts against the left inching switch 31, thereby preventing the left cam 21 from continuing to rotate in the clockwise direction.
Further, although not shown, the left cam 21 further includes an urging member which applies a force to the left cam 21 to rotate the left cam 21 in the clockwise direction. The urging member is, for example, a spring provided on a rotating shaft of the left cam 21. By the cooperation of the urging member, the second step portion 214, the stopper portion 215, and the armature 41, the left cam is positioned at the unlocked position shown in Fig. 3b, and stops rotating.
The right cam 22 has a structure that is symmetrical with respect to the center line of the armature 41 in the longitudinal direction L. Therefore, the structure of the right cam 22 is not described in the foregoing.
In the present embodiment, the trigger assembly includes the left inching switch 31 and the right inching switch 32, the left inching switch 31 corresponding to the left cam 21, and the

8 CA Phase of PCT/CN2017/112029 Our Ref.: 37761-13 (2043-160645CA) right inching switch 32 corresponding to the right cam 22. As shown in Fig. lb and Fig. lc, the movable contact of the left inching switch 31 is located at the upper left of the left cam 21, and the movable contact of the right inching switch 32 is located at the upper right of the right cam 22. Thus, when the pair of door bodies slides from the open position to the closed position, the triggering portions of the left cam 21 and the right cam 22 respectively press the movable contacts of the left inching switch 31 and the right inching switch 32 to trigger the two inching switches, thereby controlling the locking assembly to lock the left cam 21 and the right cam 22.
It should be noted that the afore-described inching switch is merely a preferred embodiment. The trigger assembly is not limited to the inching switch as long as it is able to detect that the cam rotates to the locked position and enable the locking assembly to lock. For example, the trigger assembly can use a different mechanical switch, and can also be a light-emitting portion and a light-receiving portion. When the cam is in the locked position, the cam blocks the light emitted from the light-emitting portion. When the cam is in a position other than the locked position, the cam does not block the light emitted by the light-emitting portion. Therefore, whether or not the cam is in the locked position can be determined based on whether or not the light receiving portion can receive the light emitted from the light emitting portion.
In the present embodiment, the locking assembly includes the armature 41 and the electromagnetic coil 42. The armature 41 has an elongated rod-like structure.
One end portion of the armature 41 (the upper end portion in Figs. lb and 1c) projects into the electromagnetic coil 42, so that the armature 41 can advance and retreat under the electromagnetic effect of the electromagnetic coil 42 and the gravity of the armature 42 itself. The other end portion of the armature 41 (the lower end portion in Figs. lb and 1c) is configured to be extendable into a space between the left cam 21 and the right cam 22.
When the electromagnetic coil 42 is powered on, the armature 41 is lifted up to the height shown in Fig. 3b. When the electromagnetic coil 42 is powered off, the armature 41 falls down.
A control device not shown is used for controlling to power on and power off the electromagnetic coil 42. The control device is connected to the trigger assembly. When the trigger assembly detects that the cam is in the locked position (i.e., when the inching switches 31, 32 are in the turn-on state), the control device is informed to power off the electromagnetic coil 42. When the trigger assembly detects that the cam is in a position other than the locked position (i.e., when the inching switches 31, 32 are in the turn-off state), the trigger assembly is informed to power on the electromagnetic coil 42. Further, insofar as the control device receives an instruction to unlock the lock from outside, even if the trigger assembly detects that the cam is in the locked position, the electromagnetic coil 42 would be powered on.

9 = CA 03032700 2019-02-01 CA Phase of PCT/CN2017/112029 Our Ref.: 37761-18 (2043-160645CA) Thus, when the left cam 21 and the right cam 22 rotate to the locked position, the electromagnetic coil 42 is powered off, and the armature 41 falls down under its own gravity into a space defined by the first step portions of the left cam 21 and the right cam 22, thereby simultaneously locking the left cam 21 and the right cam 22. When the lock is to be unlocked, the electromagnetic coil 42 is powered on so that the armature 41 is lifted up by the electromagnetic effect of the electromagnetic coil 42. Thus, the other end portion of the armature 41 leaves the space defined by the first step portions to realize the unlock of the lock.
Subsequently, the armature 41 abuts against the second step portions of the left cam 21 and the right cam 22 to stop the left cam 21 and the right cam 22.
It should be noted that the locking assembly of the present disclosure is not limited to the armature and the electromagnetic coil; any locking structure known in this art can be used, as long as it functions to lock the cam when the cam rotates to the locked position and unlock the cam when desired. For example, a locking assembly can be provided for each of the left cam and the right cam. In addition, holes can be provided in the left cam and the right cam respectively, and the locking assembly comprises a locking lever and an actuating mechanism.
Thus, when the cam rotates to the locked position, the actuating mechanism drives the locking lever to be inserted into the hole in the cam to lock the cam; when the lock is to be unlocked.
the actuating mechanism draws the locking lever from the hole to unlock the lock.
In the present embodiment, the manual unlocking lever 5 is rotatably provided to the lock bracket 1. In the case where the pair of door bodies of the dimidiate door (screen door) is in the closed position, the manual unlocking lever 5 can be manually operated to rotate to a predetermined position as needed, so that the armature 41 of the locking assembly and the step portions of the left cam 21 and the right cam 22 are disengaged to manually unlock the left cam 21 and the right cam 22 and open the pair of door bodies of the dimidiate door.
In the present embodiment, a spacing buffer 6 is fixed to the lock bracket 1 and is located between the left cam 21 and the right cam 22. The spacing buffer 6 includes integrated spacing buffer structures corresponding to the left door body and the right door body, respectively, so as to buffer and restrict the left door body and the right door body when the left door body and the right door body slide to the closed position. In the present embodiment, the spacing buffer 6 acts on the tip end portion of the door hooks (the left door hook 71 and the right door hook 72) attached to the left and right door bodies in the longitudinal direction L to achieve the above effects. A cushion made of an elastic material such as rubber is provided at a portion where the spacing buffer 6 contacts with the door hook.
The foregoing describes the detailed structure of the lock. The operation state and the operation process of the lock will be described with reference to the detailed structure of the = CA 03032700 2019-02-01 CA Phase of PCT/CN2017/112029 Our Ref.: 37761-18 (2043-160645CA) lock.
(Operation State and Operation Process of the Lock) As shown in Fig. 3a, the lock is in a locked state where the lock holds the pair of door bodies of the dimidiate door in the closed position. In the locked state, the engaging portions of the left cam 21 and the right cam 22 are respectively engaged with the door hooks fixed to the left door and the right door, and the other end portion of the armature 41 of the locking assembly is extended between the left cam 21 and the right cam 22 and abuts against the first step portions of the left cam 21 and the right cam 22. At the same time, the triggering portions of the left cam 21 and the right cam 22 press the left inching switch 31 and the right inning switch 32, respectively, thereby keeping the electromagnetic coil 42 in a power-off state. Thus, the left cam 21 and the right cam 22 cannot rotate due to the locking of the locking assembly, thereby reliably positioning the left and right door bodies in the closed position.
As shown in Fig. 3b, the lock is in an unlocked state. In the unlocked state, the engaging portions of the left cam 21 and the right cam 22 are respectively disengaged from the door hooks fixed to the left and right door bodies, and are stopped in a position substantially aligned to the door hooks in the height direction H. The triggering portions of the left cam 21 and the.
right cam 22 leave the left inching switch 31 and the right inching switch 32.
The left inching switch 31 and the right inching switch 32 face the small diameter portions of the stopper portions of the left cam 21 and the right cam 22, and are in the turn-off state, whereby the control device powers on the electromagnetic coil 42 to lift up the armature 41 so that the other end portion of the armature 14 leaves the space between the first step portions of the left cam 21 and the right cam 22 and is brought in abutment with the second step portions of the left cam 21 and right cam 22.
When the lock switches from the locked state shown in Fig. 3a to the unlocked state shown in Fig. 3b, that is, when the pair of door bodies of the dimidiate door slides from the closed position toward the open position, first, an instruction to unlock the lock is transmitted to the control device. The control device powers on the electromagnetic coil 42 to lift up the armature 41, thereby unlocking the left cam 21 and the right cam 22. Subsequently, the control device controls the pair of door bodies to slide from the closed position toward the open position. The pair of door bodies drives the left cam 21 and the right cam 22 to start rotating by way of the door hooks. First, the large diameter portions of the triggering portions of the left cam 21 and the right cam 22 leave the left inching switch 31 and the right inching switch 32, thereby the left inching switch 31 and the right inching switch 32 are switched from the turn-on state to the turn-off state. Subsequently, the door hooks of the pair of door bodies leave the left cam 21 and the right cam 22. The second step portions of the left cam 21 and the right cam 22 are brought CA Phase of PCT/CN2017/112029 Our Ref.: 37761-18 App!. No. 3,032,700 (2043-160645CA) in abutment with the lifted armature 41. The left cam 21 and the right cam 22 stop rotating.
When the lock switches from the unlocked state shown in Fig. 3b to the locked state shown in Fig. 3a, that is, when the pair of door bodies of the dimidiate door slides from the open position toward the closed position, first, the control device controls the pair of door bodies toward slide toward the closed position. Subsequently, when the pair of door bodies slides to a predetermined position close to the closed position, the door hooks fixed to the pair of door bodies are engaged with the engaging portions of the left cam 21 and the right cam 22, and drive the left cam 21 and the right cam 22 to start rotating. First, the second step portions of the left cam 21 and the right cam 22 leave the armature 41. During the rotation of the left cam 21 and the right cam 22, the armature 41 is in sliding contact with outer circumferential surfaces of the left cam 21 and the right cam 22 which are located between the first step portions and the second step portions. When the left cam 21 and the right cam 22 rotate to the positions where the large diameter portions of the triggering portions trigger the left inching switch 31 and the right inching switch 32, respectively, the left inching switch 31 and the right inching switch 32 are switched from the turn-off state to the turn-on state, with a signal being transmitted to the control device to power off the electromagnetic coil 42 so that the armature 41 falls down under the its own gravity into the space between first step portion of the left cam 21 and the first step portion of the right cam 22 to lock the left cam 21 and the right cam 22.
The present disclosure further provides a screen door comprising a lock having the afore-described structure and operation process. The screen door is, for example, a subway screen door. The lock is mounted on the door frame of the screen door and is used to hold a pair of door bodies of the screen door in the closed position.
By the above technical solution, the present disclosure provides a lock which is relatively simple in structure and is less likely to malfunction or cause mishandling, and a screen door .. using the same.
In addition, it should be noted that the lock according to the present disclosure can be used not only for a screen door but also for other doors having sliding door bodies. Moreover, although in the above embodiment it describes the application of the lock of the present disclosure to a dimidiate door, the present disclosure is not limited thereto.
The present disclosure can also be applied to a single door, where there is only the need of one of the left and right side structures which are linear symmetrical with respect to the center in the longitudinal direction L of the lock described in the above embodiment.
The protection scope of the present disclosure is not limited to the detailed examples of the afore-described embodiments.

Claims (12)

1. A lock, comprising:
a cam capable of rotating at least between a first position and a second position, and having an engaging portion for engaging with a member to be locked, a trigger portion, and a first step portion that is different from the trigger portion;
a locking assembly for locking the cam to make the cam unable to rotate; and a trigger assembly which is in communication with the trigger portion to actuate the locking assembly at the first step portion for locking the cam when the cam is in the second position, and to actuate the locking assembly for unlocking the cam allowing the cam to be in a position other than the second position, wherein, when the member engages with the engaging portion and the cam is in the second position and is locked by the locking assembly, the member is unable to disengage from the engaging portion.

2. The lock according to claim 1, wherein the engaging portion comprises a cutout provided in a periphery of the cam, and a recessed portion recessed toward a radial inner side of the cam relative to the cutout and toward an upstream side of a rotation direction of the cam from the first position toward the second position.

3. The lock according to claim 1 or 2, wherein the trigger assembly comprises a mechanical switch, and the trigger portion is formed at an outer periphery of the cam to actuate the mechanical switch of the trigger assembly when the cam rotates to the second position.

4. The lock according to claim 3, wherein the mechanical switch is an inching switch.

5. The lock according to claim 3 or 4, wherein the triggering portion includes a small diameter portion, a large diameter portion, and a connecting portion connecting the small diameter portion and the large diameter portion, a maximum distance from an outer circumferential surface of the small diameter portion to a rotation center of the cam is smaller than a minimum distance from the outer circumferential surface of the mechanical switch to the rotation center of the cam, and a maximum distance from an outer circumferential surface of the large diameter portion to the rotation center of the cam is greater than the minimum distance from the outer circumferential surface of the mechanical switch to the rotation center of the cam.

6. The lock according to any one of claims 1 to 5, wherein the locking assembly comprises an armature and an electromagnetic coil that actuates to advance or retreat the armature by an effect of the electromagnetic coil, wherein the electromagnetic coil is powered off to actuates the armature to lock the cam when the trigger assembly is triggered, and is powered on to actuates the armature to unlock the cam when the trigger assembly is no longer triggered or when the lock is to be unlocked.

7. The lock according to claim 6, wherein the first step portion is formed by forming a periphery of the cam into a stepped structure, when the cam is in the second position, the electromagnetic coil is powered off to advance the armature to abut against the first step portion, thereby locking the cam.

8. The lock according to claim 7, wherein the first step portion includes a first face which is parallel to a central axis of the armature when the cam is in the second position, and a second face perpendicular to the first face and parallel to an end face of the armature, when the cam is in the second position, the electromagnetic coil is powered off to advance the armature to abut against the first face and the second face.

9. The lock according to claim 7 or 8, wherein the cam further comprises a second step portion formed by forming the periphery of the cam into a stepped structure, the second step portion being formed at an upstream side of the first step portion in a rotation direction of the cam from the second position toward the first position, the second step portion abuts against the armature when the cam is in the first position.

10. The lock according to any one of claims 1 to 9, wherein the cam includes a first cam and a second cam, and the trigger assembly includes a first trigger assembly configured for the first cam and a second trigger assembly configured for the second cam.

11. The lock according to claim 10 depending on claim 8, wherein the first cam and the second cam are configured to be symmetrical with respect to a central axis of the armature, when the electromagnetic coil is powered off, the armature falls down into a space defined by the first face and the second face of the first cam and the first face and the second face of the second cam, so as to simultaneously lock the first cam and the second cam.

12. A screen door, comprising the lock according to any one of claims 1 to 11 and a door body capable of sliding between an open position and a closed position, the member being secured to the door body, wherein when the door body is in the open position, the cam is in the first position;
when the door body is in the closed position, the cam is in the second position;
during the sliding of the door body from the open position toward the closed position, the member engages with the engaging portion of the cam, and then the member makes the cam to rotate from the first position to the second position, and during the sliding of the door body from the closed position toward the open position, the locking assembly unlocks the cam, and then the member makes the cam to rotate from the second position to the first position to disengage from the cam.