Electromechanical Compression Latch

• US 20110227351A1
• Filed: 03/16/2011
• Published: 09/22/2011
• Est. Priority Date: 03/16/2010
• Status: Active Grant

• Current Assignee: Southco Incorporated (South Chester Tube Company)
• Original Assignee: Southco Incorporated (South Chester Tube Company)
• Inventors: Grosdemouge, Thibaut Bernard Paul
• Granted Patent: US 8,672,368 B2
• Time in Patent Office: Days
• US Class Current: 292/201
• CPC Class Codes: E05B 81/14 operating on bolt detents, e.g. for unlatching the bolt
• CPC Class Codes: E05B 81/20 for assisting final closing or for initiating opening
• CPC Class Codes: E05B 85/02 Lock casings
• CPC Class Codes: Y10T 292/1047 Closure
• CPC Class Codes: Y10T 292/1075 Operating means
• CPC Class Codes: Y10T 292/1082 Motor
• CPC Class Codes: Y10T 292/308 Swinging catch

Abstract

The present invention is directed to improvements in latch design. The illustrated embodiment of the present invention is a rotary pawl latch with the capability to provide a compressive force between the first member and the second member. The illustrated embodiment of the present invention is of an electromechanical type. The control circuit of the latch detects when a striker attached to one member, for example a door, has moved the pawl to a first latched position. A motor is then activated that drives the pawl to a second latched position to provide compression between the first member and a second member, for example a door frame.

Claims

1. A latch (200) adapted for securing a closure member (300) in a predetermined position, the closure member being provided with a striker (308), the latch comprising:

a latch housing (202);

a pawl (204);

a trigger or catch (206); and

an electrically operated actuator assembly (208) capable of selectively moving said trigger (206) out of engagement with said pawl (204) and rotating said pawl from a first latched position to a second latched position to move the striker (308) inward relative to said housing (202).

2. The latch according to claim 1, wherein the latch (200) is adapted for attachment to a second member such that the latch can be engaged by the striker (308) for securing the closure member (300) in the predetermined position relative to the second member.

3. The latch according to claim 1, wherein said housing (202) has an opening that allows at least a portion of the striker (308) to enter said housing (202) for engagement by said pawl (204).

4. The latch according to claim 3, wherein the latch further comprises a support plate (215) fixedly positioned within said housing (202), said opening is in the form of a slot (212) that passes through a first portion (211) of said housing (202), said slot (212) forms an open, approximately U-shaped cut-out in said housing (202) as viewed in profile, said slot (212) allows an unobstructed path for the striker (308) to engage said pawl (204) when said pawl is in an open configuration relative to said support plate (215), and said slot (212) is sized such that said housing (202) will not interfere with movement of the striker (308) relative to said housing (202) as said pawl (204) is moved from an open configuration to a closed configuration relative to said support plate (215) by contact with the striker (308) and as said pawl (204) is rotated from said first latched position to said second latched position relative to said housing (202) by said electrically operated actuator assembly (208).

5. The latch according to claim 1, wherein said electrically operated actuator assembly (208) comprises:

a cam gear (218) including a gear wheel (222), a first cam (203), and a second cam (205), said cam gear (218) being rotationally supported in said housing (202) for rotation about an axis of rotation, said first cam (203) having a cam lobe (207) located at a distance from said axis of rotation of said cam gear (218), said first cam (203) acting to drive said pawl (204) from said first latched position to said second latched position when said cam gear (218) is rotated in a first direction, said second cam (205) being in the form of a raised, arc-shaped, and elongated rib eccentrically positioned relative to said axis of rotation of said cam gear (218), said second cam (205) acting to disengage said trigger from said pawl when said cam gear is rotated in a second direction;

a circuit board (230);

a latch control circuit (235);

a motor (210) selectively powering rotation of said cam gear; and

at least two sensors (332, 326), including a first sensor (332) and a second sensor (326), mounted on said circuit board (230);

wherein said pawl (204) is provided with a pawl slot (258) to capture and hold the striker (308) when said pawl (204) is in either one of a first latched position and a second latched position, wherein with the latch (200) initially in an unlatched configuration, as the closure member (300) is closed, the striker (308) will be positioned and captured in said pawl slot (258) with said pawl (204) being moved to said first latched position,

wherein said first sensor (332) detects when said pawl (204) reaches said first latched position, whereupon said first sensor (332) generates a signal to said latch control circuit (235) that causes electrical current to be supplied to said motor (210) to thereby cause rotation of said cam gear (218) to move said pawl (204) to said second latched position.

6. The latch according to claim 5, further comprising:

a one-way trigger actuating lever (286) that moves said trigger (206) when rotated in a first direction, but that does not engage said trigger (206) when rotated in a second direction.

7. The latch according to claim 5, wherein said second sensor (326) is used to detect the position of said cam gear (218), wherein said second sensor (326) at least detects when said cam gear (218) is in its starting position, and wherein said second sensor (326) then generates a signal to said latch control circuit (235) when said cam gear (218) is in its starting position to thereby allow said latch control circuit (235) to detect that said cam gear (218) is in its starting position.

8. The latch according to claim 7, further comprising:

a one-way trigger actuating lever (286) that moves said trigger (206) when rotated in a first direction, but that does not engage said trigger (206) when rotated in a second direction.

9. The latch according to claim 7, further comprising a third sensor (316) provided on said circuit board (230), wherein said third sensor (316) is used to detect when said pawl (204) reaches said second latched position, whereupon said third sensor (316) generates a signal to said latch control circuit (235) to thereby allow said latch control circuit (235) to detect when said pawl (204) is in said second latched position.

10. The latch according to claim 9, further comprising:

a one-way trigger actuating lever (286) that moves said trigger (206) when rotated in a first direction, but that does not engage said trigger (206) when rotated in a second direction.

11. The latch according to claim 9, further comprising:

a striker detector (318) pivotally supported within said latch housing (202), said striker detector (318) being provided with a striker detector spring (244) that biases said striker detector (318) into occupying a first position coincident with a position occupied by the striker (308) when the striker (308) is captured by said pawl (204) and said pawl (204) is in said second latched position, wherein when the striker (308) is captured by said pawl (204) and said pawl (204) is in said second latched position, said striker detector (318) is pushed to a second position by the striker (308).

12. The latch according to claim 11, further comprising:

a fourth sensor (320) is provided on said circuit board (230), said fourth sensor (320) at least detecting when said striker detector (318) is in its second position, said fourth sensor (320) generating a signal to said latch control circuit (235) when said striker detector (318) is in its second position to thereby allow said latch control circuit (235) to detect that the striker (308) is properly secured when said pawl (204) is in said second latched position.

13. The latch according to claim 12, further comprising:

a one-way trigger actuating lever (286) that moves said trigger (206) when rotated in a first direction, but that does not engage said trigger (206) when rotated in a second direction.

14. The latch according to claim 5, further comprising:

a striker detector (318) pivotally supported within said latch housing (202), said striker detector (318) being provided with a striker detector spring (244) that biases said striker detector (318) into occupying a first position coincident with a position occupied by the striker (308) when the striker (308) is captured by said pawl (204) and said pawl (204) is in said second latched position, wherein when the striker (308) is captured by said pawl (204) and said pawl (204) is in said second latched position, said striker detector (318) is pushed to a second position by the striker (308).

15. The latch according to claim 14, further comprising:

a one-way trigger actuating lever (286) that moves said trigger (206) when rotated in a first direction, but that does not engage said trigger (206) when rotated in a second direction.

16. The latch according to claim 1, further comprising:

a striker detector (318) pivotally supported within said latch housing (202), said striker detector (318) being provided with a striker detector spring (244) that biases said striker detector (318) into occupying a first position coincident with a position occupied by the striker (308) when the striker (308) is captured by said pawl (204) and said pawl (204) is in said second latched position, wherein when the striker (308) is captured by said pawl (204) and said pawl (204) is in said second latched position, said striker detector (318) is pushed to a second position by the striker (308).

17. The latch according to claim 16, further comprising:

a one-way trigger actuating lever (286) that moves said trigger (206) when rotated in a first direction, but that does not engage said trigger (206) when rotated in a second direction.

18. The latch according to claim 5, wherein said motor (210) has an output shaft (220) and wherein said electrically operated actuator assembly (208) further comprises:

a worm gear (214) attached to said output shaft (220) of said motor (210) such that said worm gear (214) rotates with said shaft (220) as a unit; and

a combination gear (216) that drives said cam gear (218), said output shaft (220) rotating in response to said motor being energized by supplying a current having a polarity to said motor, wherein reversing the polarity of the current supplied to said motor (210) causes a direction of rotation of said output shaft (220) to be reversed, and wherein rotation of said worm gear (214) causes rotation of said combination gear (216).

19. The latch according to claim 18, further comprising:

a one-way trigger actuating lever (286) that moves said trigger (206) when rotated in a first direction, but that does not engage said trigger (206) when rotated in a second direction.

20. The latch according to claim 7, wherein after said pawl (204) is rotated to its second latched position, when the second sensor (326) detects that said can gear is back in its starting position then current supply to said motor (210) is turned off.

21. The latch according to claim 20, wherein when normal closing of the panel (300) is blocked, after a predetermined time without a signal from said second sensor (326) said latch control circuit (235) reverses the polarity of the current to said motor (210) to disengage said trigger (206) from said pawl (204) to allow the striker (308) to be released and to return the latch (200) to said unlatched configuration.

22. The latch according to claim 12, wherein after said pawl (204) is rotated to its second latched position, when the second sensor (326) detects that said can gear is back in its starting position then current supply to said motor (210) is turned off.

23. The latch according to claim 22, wherein when the striker (308) is properly secured with said pawl (204) being in said second latched position and said cam gear (218) being in its starting position, activation of the latch (200) by a user results in said latch control circuit (235) operating to rotate said cam gear (218) from its starting position of in a direction opposite a direction of rotation of said cam gear (218) when said pawl (204) is being moved from said first latched position to said second latched position, to disengage said trigger (206) from said pawl (204) to allow the striker (308) to be released.

24. The latch according to claim 23, wherein when the second sensor (326) senses that said cam gear (218) has returned to its starting position, said second sensor (326) signals said latch control circuit (235) to cease energizing said motor (210).

25. The latch according to claim 12, wherein when said pawl (204) is moved to said second latched position as detected by said third sensor (316), while the striker detector (318) does not indicate that the striker (308) is captured by said pawl (204), said latch control circuit (235) reverses the current to said motor (210), as compared to the current supplied to said motor when said pawl (204) is being moved from said first latched position to said second latched position, to disengage said trigger (206) from said pawl (204) and return the latch (200) to said unlatched configuration.

26. The latch according to claim 24, wherein when said pawl (204) is moved to said second latched position as detected by said third sensor (316), while the striker detector (318) does not indicate that the striker (308) is captured by said pawl (204), said latch control circuit (235) reverses the current to said motor (210), as compared to the current supplied to said motor when said pawl (204) is being moved from said first latched position to said second latched position, to disengage said trigger (206) from said pawl (204) and return the latch (200) to said unlatched configuration.

27. A method of operating a latch (200) adapted for securing a closure member (300) in a predetermined position, the closure member being provided with a striker (308), wherein the latch comprises:

a latch housing (202);

a pawl (204);

a trigger or catch (206); and

an electrically operated actuator assembly (208) capable of selectively moving said trigger (206) out of engagement with said pawl (204) and rotating said pawl from a first latched position to a second latched position to move the striker (308) inward relative to said housing (202),

wherein said electrically operated actuator assembly (208) comprises;

a cam gear (218) including a gear wheel (222), a first cam (203), and a second cam (205), said cam gear (218) being rotationally supported in said housing (202) for rotation about an axis of rotation, said first cam (203) having a cam lobe (207) located at a distance from said axis of rotation of said cam gear (218), said first cam (203) acting to drive said pawl (204) from said first latched position to said second latched position when said cam gear (218) is rotated in a first direction, said second cam (205) being in the form of a raised, arc-shaped, and elongated rib eccentrically positioned relative to said axis of rotation of said cam gear (218), said second cam (205) acting to disengage said trigger from said pawl when said cam gear is rotated in a second direction;

a circuit board (230);

a latch control circuit (235);

a motor (210) selectively powering rotation of said cam gear; and

at least two sensors (332, 326), including a first sensor (332) and a second sensor (326), mounted on said circuit board (230);

wherein said pawl (204) is provided with a pawl slot (258) to capture and hold the striker (308) when said pawl (204) is in either one of a first latched position and a second latched position, wherein with the latch (200) initially in an unlatched configuration, as the closure member (300) is closed, the striker (308) will be positioned and captured in said pawl slot (258) with said pawl (204) being moved to said first latched position,

wherein said second sensor (326) at least detects when said cam gear (218) is in its starting position, and wherein said second sensor (326) then generates a signal to said latch control circuit (235) when said cam gear (218) is in its starting position;

the method comprising the steps of;

detecting when said pawl (204) reaches said first latched position using said first sensor (332), whereupon said first sensor (332) generates a signal to said latch control circuit (235);

supplying current with a first polarity to said motor (210) to cause rotation of said cam gear (218) in a first direction to move said pawl (204) to said second latched position; and

ceasing the supply of current to said motor (210) when said second sensor (326) detects that said cam gear (218) is in its starting position.

28. The method according to claim 27, further comprising the step of reversing the polarity of the current from the first polarity to a second polarity to reverse the direction of rotation of the cam gear (218) after a predetermined period of time has passed without detecting that the cam gear (218) has reached its starting position.

29. The method according to claim 27, further comprising the steps of:

detecting that a user has acted to activate the latch (200); and

supplying current with a second polarity opposite the first polarity to a second polarity to rotate the cam gear (218) in a second direction opposite said first direction to thereby release the striker (308); and

ceasing the supply of current to said motor (210) when said second sensor (326) detects that said cam gear (218) is in its starting position.

30. The method according to claim 27, wherein the latch further comprises:

a third sensor (316) provided on said circuit board (230), wherein said third sensor (316) is used to detect when said pawl (204) reaches said second latched position, whereupon said third sensor (316) generates a signal to said latch control circuit (235) to thereby allow said latch control circuit (235) to detect when said pawl (204) is in said second latched position;

a striker detector (318) pivotally supported within said latch housing (202), said striker detector (318) being provided with a striker detector spring (244) that biases said striker detector (318) into occupying a first position coincident with a position occupied by the striker (308) when the striker (308) is captured by said pawl (204) and said pawl (204) is in said second latched position, wherein when the striker (308) is captured by said pawl (204) and said pawl (204) is in said second latched position, said striker detector (318) is pushed to a second position by the striker (308); and

a fourth sensor (320) is provided on said circuit board (230), said fourth sensor (320) at least detecting when said striker detector (318) is in its second position, said fourth sensor (320) generating a signal to said latch control circuit (235) when said striker detector (318) is in its second position to thereby allow said latch control circuit (235) to detect that the striker (308) is properly secured when said pawl (204) is in said second latched position;

the method further comprising the steps of;

detecting whether or not said pawl (204) has reached said second latched position using said third sensor (316);

detecting whether or not the striker (308) is properly secured using said fourth sensor (320); and

supplying current with a second polarity opposite the first polarity to a second polarity to rotate the cam gear (218) in a second direction opposite said first direction to thereby return the latch (200) to the unlatched configuration if it is detected that said pawl (204) has reached said second latched position and that the striker (308) is not properly secured.