Linear actuator

• US 5,727,847 A
• Filed: 02/28/1997
• Issued: 03/17/1998
• Est. Priority Date: 03/01/1996
• Status: Expired due to Fees

• Current Assignee: Maple Automotive Innovations Incorporated
• Original Assignee: Maple Automotive Innovations Incorporated
• Inventors: Martone, Michael A., Secord, Tyrone R.
• Primary Examiner(s): Cuomo, Peter M.
• Assistant Examiner(s): Allred, David E.
• Application Number:
  US08/807,711
• Time in Patent Office: 382 Days
• Field of Search: 297/375, 297/362.12, 297/361.1, 297/378.11, 248/424
• US Class Current: 297/375
• CPC Class Codes: B60N 2/23 by linear actuators, e.g. linear screw mechanisms

Abstract

A linear actuator is used in an adjustable seat back recliner mechanism to provide infinitely adjustable operation. The actuator rod is maintained in its locked position by the contact of a lower friction surface of the rod with a friction surface on a lower clamp member. Upper clamp members are further seated against an upper surface of the actuator rod. When a sudden force is applied such as in a vehicle collision, an inertial locking element is swung upwardly into contact with the actuator rod to positively lock the actuator rod to the body of the actuator preventing any relative movement.

Claims

1. A linear actuator for use in a position adjusting mechanism for adjusting the position of a movable element relative to a stationary member, comprising:

a longitudinally extending actuator rod having an upper planar surface and a lower planar friction surface connected with opposed sides;

an elongate lower clamp member having an upper planar friction surface for locking engagement with said lower planar friction surface of said actuator rod, and a central aperture for receiving a lock release shaft;

a first pair of generally triangular shaped and parallel spaced lock plates located adjacent to one side of said actuator rod and a second pair of generally triangular shaped and parallel spaced lock plates located adjacent the other side of said actuator rod, said pairs of lock plates being pivotally connected to said lower clamp member at opposed ends of said lower clamp member and extending upwardly and inwardly to overlap each other at a midpoint of said lower clamp member;

pivotal mounting means being received in an upper aperture of each of said lock plates for mounting said actuator rod to said stationary member;

a pair of upper clamp members, each pivotally connected to one of said lock plates and presenting a planar surface in contact with said upper surface of said actuator rod;

biasing means for biasing said upper clamp members in contact with said upper planar surface of said actuating rod, said biasing means creating a locking engagement between said lower planar friction surface of said rod and said upper planar friction surface of said lower clamp member;

said lock release shaft extending through said central aperture of said lower clamp member and at least one cam member being mounted to said lock release shaft, said at least one cam member upon rotation of said lock release shaft actuating said lock plates upwardly and outwardly to release said actuating rod for movement relative to said clamp members and permitting position adjustment of said movable element through said position adjusting mechanism; and

an inertial locking element freely suspended from said lock release shaft and within an arcuate relief channel located centrally within said lower clamp, said inertial locking element including opposing upper corners and, upon the occurrence of a sudden impact force, said locking element rotating about said shaft such that a selected one of said upper corners engages said lower planar friction surface of said actuator rod to reinforce the engagement between said clamp member and said actuator rod and to prevent any relative movement therebetween.

2. The linear actuator according to claim 1, said at least one cam member further comprising a front lift plate and a rear lift plate arranged on opposite sides of said lower clamp member and keyed to said lock release shaft, each of said lift plates further including an upper cam surface which contacts a lower edge of said lock plates as said lock release shaft is rotated for moving said lock plates upward.

3. The linear actuator according to claim 2 wherein said lift plates each include a guide pin projecting through a guide slot in one of a front and rear retention plate.

4. The linear actuator according to claim 3 wherein said mounting fastener and said lock release shaft pass through said front and rear retention plates and said mounting fastener and lock release shaft are axially retained against said front and rear retention plates.

5. The linear actuator according to claim 4, said first pair of triangular shaped plates further comprising a front left lock plate and a front right lock plate and said second pair of triangular shaped plates including a rear left lock plate and a rear right lock plate.

6. The linear actuator according to claim 5 further including a left lift pin extending between said front left lock plate and said rear left lock plate, and a right lift pin extending between said front right lock plate and said rear right lock plate, said lift pins acting against said lower planar friction surface of said actuator rod as said lock release shaft is rotated and said upper cam surfaces of said front and rear lift plates contacting the lower edges of said lock plates to positively lift said actuator rod free from said lower clamp member to permit position adjustment of said movable element.

7. The linear actuator according to claim 2, said biasing means further comprising a spring connected between said pairs of lock plates to bias said pair of upper clamp members in contact with said upper planar surface of said actuating rod.

8. The actuator according to claim 6 wherein said upper planar surface of said lower clamp member and said lower planar friction surface of said actuator rod have inter-locking serrations.

11. The linear actuator according to claim 1, said pivotal mounting means further comprising an main rivet portion pivotally secured through said upper apertures of said lock plates, said upper apertures each being substantially elongated and diagonal in shape and arranged in substantially overlapping fashion.

12. The linear actuator according to claim 11, said biasing means further comprising a coil spring mounted to said lock release shaft and including an extending end in abutting engagement with a tab portion extending from said lower clamp member.

13. The linear actuator according to claim 12, further comprising a first vertically actuable lift member positioned forwardly of said pairs of lock plates and a second vertically actuable lift member positioned rearwardly of said pairs of lock plates, said forward and rearward lift members each further including apertures at upper ends thereof through which is received opposite ends of said main rivet portion, said lift members each further including a slotted portion through which is engaged a keyed portion of said extending lock release shaft, said slotted portions each further including a main vertical portion and a downwardly angled portion which is bounded in part by an angled shoulder.

14. The linear actuator according to claim 13, further comprising a forward rotating cam member and a rearward rotating cam member which are arranged on opposing sides of said lower clamp member, said rotating cam members each further including a keyed aperture portion to which is secured said keyed portion of said extending lock release shaft, said rotating cam members each including a projecting pin portion which is received within said slotted portion of said associated lift member.

15. The linear actuator according to claim 14, further comprising a left lift pin extending between said front left lock plate and said rear left lock plate and a right lift pin extending between said front right lock plate and said rear right lock plate, said left and right lift pins being arranged in a planar and spaced apart distance and being pivotally and upwardly movably secured to said associated lock plates so as to pass underneath said lower planar friction surface of said actuator rod.

16. The linear actuator according to claim 15, further comprising a disk member and a rotating washer portion which are arranged in opposing fashion to a rear face of said rear lift member, a cylindrical rearward tip of said keyed extending portion of said lock release shaft passing through an aperture in said washer and being mounted to said disk member, a lock release handle being mounted to an opposing end of said lock release shaft and being rotated so that said forward and rearward cam members and their associated pins travel along said slotted portions in said forward and rearward lift members, coacting against said angled shoulder portions of said lift members and causing said lift members to actuate upwardly, in turn upwardly and outwardly pivoting said lock plates and causing said left and right lift pins to actuate upwardly and to unseat said lower planar friction surface from said upper planar friction surface of said lower clamp member.

9. A linear actuator for use in a position adjusting mechanism for adjusting the position of a movable element relative to a stationary member, comprising:

said movable member including a longitudinally extending actuator rod having a horizontal extending planar friction surface;

a stationary clamp member having a horizontal extending friction surface normally engaging the horizontal extending planar surface of said actuator rod to maintain said actuator rod stationary with respect to said clamp member;

means for moving the horizontally extending planar friction surface of said actuator rod vertically away from the horizontally extending planar surface of said clamp member to permit longitudinal adjustment of said actuator rod relative to said clamp member; and

an inertial locking element rotationally mounted relative to one of said actuator rod and clamping member so that when a sudden inertial force is applied to said actuator, said inertial locking element will be rotated to lock against the other of said actuator rod and clamping member to positively prevent any relative movement between said actuator rod and said clamping member.

10. The actuator according to claim 9 wherein said linear actuator has a body portion having an aperture for receiving a mounting fastener for mounting said actuator to said stationary member;

a lock release shaft extending through a central aperture in said stationary clamping member and a cam connected with said lock release shaft for moving said actuator rod vertically away from said clamping member when said lock release shaft is rotated to permit longitudinal adjustment of said actuator rod relative to said clamp member, and

said inertial locking element being rotatably mounted on said lock release shaft so that when a sudden inertial force is applied to said actuator, said inertial locking element will be rotated to lock against said actuator rod to positively prevent any relative movement between said actuator rod and said clamping member.

17. A linear actuator for use in a position adjusting mechanism for adjusting the position of a seat back relative to a seat bottom, said linear actuator comprising:

a longitudinally extending actuator rod having a substantially U-shape in cross section with a front side, a rear side and an interconnecting base exhibiting a lower planar friction surface;

an elongate lower clamp member having an upper planar friction surface for locking engagement with said lower planar friction surface of said actuator rod, said lower clamping member having a central aperture for receiving a lock release shaft;

a first pair of generally triangular shaped and parallel spaced lock plates located adjacent to one side of said actuator rod and a second pair of generally triangular shaped and parallel spaced lock plates located adjacent the other side of said actuator rod, said pairs of lock plates being pivotally connected to said lower clamp member at opposed ends of said lower clamp member and extending upwardly and inwardly to overlap each other at a midpoint of said lower clamp member, said pairs of lock plates further being pivotally connected to a main rivet through upper apertures formed in overlapping portions of said lock plates;

a left lift pin extending underneath said lower planar friction surface of said actuator rod at a first location and pivotally and upwardly movably mounted a front left lock plate and a rear left lock plate, a right lift pin extending underneath said lower planar friction surface at a second spaced apart location and pivotally and upwardly movably mounted to a front right lock plate and a rear right lock plate;

a forward rotating cam member and a rearward rotating cam member mounted to said lock release shaft underneath said pairs of lock plates and on opposing sides of said lower clamp member;

a first vertically actuable lift member secured to said lock release shaft forwardly of said forward rotating cam member and a second vertically actuable lift member secured to said lock release shaft rearwardly of said rearward rotating cam member, said forward and rearward lift members further including interior slotted portions defined in part by an engaging shoulder portion and through which is received a pin projecting from said associated cam member, said forward and rearward lift members each further including an upper apertured portion through which is received opposing ends of said main rivet; and

a left upper clamp member pivotally secured between said front left lock plate and said rear left lock plate and a right upper clamp member pivotally secured between said front right lock plate and said rear right lock plate, said left and right upper clamp members seating within said U-shaped channel of said actuator rod in a locking position;

wherein, upon rotation of a lock release handle secured to an opposing end of said lock release shaft, said pin members extending from said cam members rotate within the interior slotted portions of their associated lift members, further rotation of said lock release shaft causing said pin members to coact against said engaging shoulder portions, in turn causing said lift members to upwardly actuate, in turn causing said pairs of lock plates to upwardly and outwardly pivot about their connection with said main rivet and said left and right lift pins to elevate upwardly and to unseat said lower planar friction surface of said actuator rod from said upper planar friction surface of said lower clamp member to permit linear adjustment of said actuator rod relative to said seat bottom.