System for locking a linear device for rapidly adjusting and immobilizing a movable part relative to a fixed part

• US 4,782,715 A
• Filed: 10/13/1987
• Issued: 11/08/1988
• Est. Priority Date: 10/13/1986
• Status: Expired due to Fees

• Current Assignee: Rockwell Automation, Inc.
• Original Assignee: Rockwell-Cim
• Inventors: Chevance, Claude
• Primary Examiner(s): STAAB, LAWRENCE J
• Application Number:
  US07/107,696
• Time in Patent Office: 392 Days
• Field of Search: 74/89.15, 74/411.5, 74/424.8 R, 74/586, 188/67, 188/196 D, 188/202, 297/348, 297/355, 297/361
• US Class Current: 74/89.39
• CPC Class Codes: B60N 2/1615 Parallelogram-like structure
• CPC Class Codes: B60N 2/164 Linear actuator, e.g. screw mechanism
• CPC Class Codes: B60N 2/233 by linear screw mechanisms
• CPC Class Codes: B60N 2/929 linear
• CPC Class Codes: F16H 25/2025 with means to disengage the nut or screw from their counterpart; Means for connecting screw and nut for stopping reciprocating movement F16H25/2015 takes precedence
• CPC Class Codes: F16H 25/2454 Brakes; Rotational locks
• CPC Class Codes: Y10T 74/18704 Means to selectively lock or retard screw or nut
• CPC Class Codes: Y10T 74/19637 with brake means for gearing

Abstract

The adjusting device (7) comprises a screw (8) and a nut (12) engaged in a housing (16). The latter and the screw cooperate with a fixed part and a movable part. The locking system comprises a locking cylinder (23) provided with inner screw threads (24-26) conjugate with outer screw threads (22) of the nut (12), and in these two series of screw threads complementary axial splines are provided so that the locking cylinder (23) locks the nut (12) against rotation when their screw threads and respective splines are in engagement with each other. The locking cylinder (23) may be controlled by a cable (29). Application in the locking in particular of adjusting devices for table guides of woodworking machines and seat structures of vehicles.

Claims

1. A locking system in combination with a linear device for rapidly adjusting and immobilizing a movable part relative to a fixed part, said linear device comprising a housing, at least a pair of elements consisting of a screw and a nut which are screw threadedly interengaged and carried by the housing for cooperation with the fixed and movable parts, the helix angles of the screw threads of the screw and nut being sufficiently large to ensure that the efficiency of the conversion of translation of one of said pair of elements into rotation of the other of said pair of elements is slightly positive, said system being adapted to be capable of locking a rotary element of said pair of elements after adjustment of the position of the movable part of said parts, said system comprising an abutment in the housing, a locking cylinder portion axially movably mounted in the housing and provided with inner screw threads conjugate with outer screw threads on the nut, and complementary splines which are provided in said conjugate screw threads and are parallel to the screw, an elastically yieldable element for biasing the locking cylinder portion against said abutment in the housing and into a position in which the splines of the locking cylinder portion are engaged with the splines of the nut and lock the nut against rotation, said adjusting device being then at rest, a screw thread formed in the housing and similar to the screw threads of the outer nut, so that the nut is capable of rotating in said screw thread formed in the housing and travelling axially through the housing and in the screw threads of the spline of locking cylinder portion when the locking cylinder portion is not engaged with the spline of nut, and manual control means associated with the locking cylinder portion for axially displacing the locking cylinder portion disengaging the locking cylinder portion from the splines of the nut and thereby unlocking the nut as concerns rotation and permitting the nut to rotate in the screw thread of the housing.

2. A device according to claim 1, wherein the housing has walls defining a compartment and the locking cylinder portion is disposed in the compartment, the walls of the compartment axially guiding the locking cylinder portion, the manual control means comprising a cable having an end integral with the locking cylinder portion and extending in a direction parallel to the screw, and said elastically yieldable element being a coil spring coaxial with the cable and bearing against an end of the compartment of the housing for exerting on the locking cylinder portion a thrust which maintains the splines of the locking cylinder portion in engagement with the splines of the outer screw threads of the nut so long as a sufficient pull in a direction opposed to said thrust is not exerted on the cable.

3. A device according to claim 2, wherein the screw thread of the housing is interrupted in an angular sector equal to an angular sector occupied by the locking cylinder portion so that the screw threads of the locking cylinder portion are capable of being placed in phase with the screw thread of the housing when the locking cylinder portion is in a nut-unlocking position thereof which nut may then rotate freely in a cavity defined by the housing and the locking cylinder portion.