Latch assembly

• US 20020167178A1
• Filed: 04/24/2002
• Published: 11/14/2002
• Est. Priority Date: 04/28/2001
• Status: Active Grant

• Current Assignee: Meritor Technology, Inc. (Cummins Incorporated)
• Original Assignee: Meritor Light Vehicle Systems UK Limited (Cummins Incorporated)
• Inventors: Coleman, Peter, Spurr, Nigel Victor, Ketelsen, Morten
• Granted Patent: US 6,773,042 B2
• Time in Patent Office: Days
• US Class Current: 292/201
• CPC Class Codes: E05B 77/02 for accident situations
• CPC Class Codes: E05B 81/14 operating on bolt detents, e.g. for unlatching the bolt
• CPC Class Codes: Y10S 292/23 Vehicle door latches
• CPC Class Codes: Y10S 292/62 Lost motion connections
• CPC Class Codes: Y10S 292/65 Emergency or safety
• CPC Class Codes: Y10T 292/1047 Closure
• CPC Class Codes: Y10T 292/1079 Gear
• CPC Class Codes: Y10T 292/1082 Motor

Abstract

A latch assembly (10, 110, 210, 310) for releasably securing a door in a closed position, the assembly comprising an actuator (15, 115, 215, 315) with an actuator output, the actuator having a first relatively fast acting low force output mode and a second relatively slow acting high force output mode, the actuator output being interconnected with a latch bolt (46, 146, 246, 346) of the assembly such that the latch bolt may be relatively rapidly released by the actuator operating in its first output mode when the load required to unlatch the latch bolt is relatively low, but relatively slowly unlatched by the second output mode when the load required to unlatch the latch bolt is relatively high.

Claims

1. A latch assembly for releasably securing a door in a closed position, the assembly comprising an actuator with an actuator output, the actuator having a first relatively fast acting low force output mode and a second relatively slow acting high force output mode, the actuator output being interconnected with a latch bolt of the assembly such that the latch bolt may be relatively rapidly released by the actuator operating in its first output mode when the load required to unlatch the latch bolt is relatively low, but relatively slowly unlatched by the second output mode when the load required to unlatch the latch bolt is relatively high.

2. A latch assembly according to claim 1 wherein a mechanical linkage interconnects the actuator output and the latch bolt.

3. A latch assembly according to claim 1 wherein the first and second output modes are provided in sequence.

4. A latch assembly according to claim 3 wherein the modes are provided in a predetermined sequence.

5. A latch assembly according to claim 1 wherein the actuator comprises a cam connected to a drive means.

6. A latch assembly according to claim 2 wherein the actuator comprises a resilient member.

7. A latch assembly according to claim 6 wherein the resilient member has sufficient resilience to transmit the low force through the linkage but insufficient resilience to transmit the high force.

8. A latch assembly according to claim 7 wherein a stop is provided such that once the resilience of the resilient member has been overcome, the resilient member is bypassed.

9. A latch assembly according to claim 5 wherein the first output mode is achieved by a relatively fast acting profile portion of the cam.

10. A latch assembly according to claim 5 wherein the second output mode is achieved by a relatively slow acting profile portion of the cam.

11. A latch assembly according to claim 3 wherein the cam is a linear cam.

12. A latch assembly according to claim 3 wherein the cam is a rotary cam.

13. A latch assembly according to claim 1 wherein the actuator self-regulates the relationship between its output force and output speed.

14. A latch assembly according to claim 13 wherein the resilient member effects self-regulation.

15. A latch assembly according to claim 13 wherein the actuator converts to a rotary actuator input to a substantially linear actuator output.

16. A latch assembly according to claim 15 wherein self-regulation is achieved by adjusting the effective lever length between the actuator input and the actuator output.

17. A latch assembly according to claim 15 wherein the adjustment is achieved by a pin and slot arrangement.

18. A latch assembly according to claim 15 wherein adjustment is achieved by a pivoted link arrangement.

19. A latch assembly according to claim 17 wherein the resilient member biases the actuator output towards its greatest lever length.