Machine element or mechanism – Control lever and linkage systems – Hand operated
Reexamination Certificate
2000-07-26
2002-02-12
Bucci, David A. (Department: 3682)
Machine element or mechanism
Control lever and linkage systems
Hand operated
Reexamination Certificate
active
06345549
ABSTRACT:
This application is the national phase under 35 U.S.C. §371 of PCT International Application No. PCT/AU98/00784 which has an International filing date of Sep. 21, 1998, which designated the United States of America.
FIELD OF THE INVENTION
This invention relates to an actuator enabling adjustment of a flexible line, cable, rope or the like.
SUMMARY OF THE INVENTION
The device of the invention is suitable for generating tension in a flexible line, such as a cable, rope or the like. However, it also is suitable for generating a pulling force, such as to adjust the position of a member, with the force being transmitted by such flexible line. In one embodiment, the actuator of the invention comprises a component of an adjustable headrest for a seat, such as a vehicle seat. In part, the actuator is described herein with reference to that application. However, it is to be understood that the actuator of the invention is well suited for use in a wide variety of other applications.
The present invention provides an actuator for enabling adjustment of a flexible line, wherein the actuator includes a screw threaded spindle and a co-operatively engaging threaded adjustment member which comprises a nut in having an internal screw thread by which it is in screw threaded engagement with an external screw thread of the spindle, and wherein the adjustment member is rotatable relative to the spindle so as to cause axial movement of the spindle. At one end of the spindle there is mounted thereon a turning block or pulley which is rotatable on an axis which extends transversely with respect to the axis of the spindle whereby a flexible line such as a cable, rope or the like can be retained in relation to the spindle by being passed around the turning block or pulley.
In one arrangement, the actuator includes a body or housing in which the spindle and the adjustment member are provided. The spindle may be extendable from the housing and, in that case, the turning block or roller may be located exteriorly of the body or housing during at least part of a range of axial movement for the spindle. However, it is preferred that the spindle is not extendable from the housing and that, throughout the range of axial movement for the spindle, the turning block or pulley also is within the body or housing.
The housing is preferably adapted to restrain the spindle against rotation as it is moved axially with rotation of the adjustment member. For this purpose the housing may define a groove or guideway which extends parallel to the axis of the spindle, with a portion of the spindle locating in the groove or guide way. Alternatively, the spindle may define a groove or guideway which extends parallel to the spindle axis, with a projecting portion of the housing being received therein.
The adjustment member is a nut in that it has an internal thread by which it is in threaded engagement with an external thread of the spindle. The nut most preferably is such that, with its rotation, the nut is able to move along that axis as the spindle moves axially relative to the nut. Thus, the nut most preferably is externally threaded and is in threaded engagement with an internal thread defined by the housing, with the external thread of the nut being of opposite hand to its internal thread. In that arrangement, rotation of the nut and, hence, axial movement of the spindle, can be achieved manually or by a motorised drive.
In a mechanical arrangement, there may be a knob or handle journalled on or in the housing, with the knob engaged with the nut whereby the nut is rotatable with the knob. The engagement may be such that the nut is axially adjustable relative to the knob as it rotates with the knob. In one arrangement the engagement is by respective splines extending parallel to the axis of the spindle such that manual rotation of the knob causes rotation of the nut while enabling axial movement of the nut relative to the knob. With an arrangement having a motorised drive, there may be for example a similar splined engagement between the nut and a rotatable output member of a drive motor.
In an embodiment of the actuator of the invention which is suitable for use with or in an adjustable headrest for a vehicle seat (herein referred to as “the headrest embodiment”), the actuator is of elongate form in the direction of the spindle axis. The actuator is adapted at a first end to receive a flexible line by which the headrest is adjustable, while manual or powered drive is able to be provided at its second end to operate the actuator. For ease of further description, the first and second ends are referred to as the cable end and the drive end, respectively, while the corresponding ends of the housing, the spindle and the adjustment member are similarly distinguished.
In the headrest embodiment, the housing overall has a hollow cylindrical form which is open at its drive end, but preferably is partially closed at its cable end. Over a portion of its internal surface nearer to the drive end, the cable defines an internal screw thread. The nut is of cylindrical form and over a portion of its length extending from its cable end, the nut defines an internal screw thread. Over a part of its length from the drive end, the nut defines an external screw thread by which it is engaged with the internal thread of the housing, while the external thread is of opposite hand to the internal thread of the nut. Also the nut is recessed axially inwardly from its drive end to define internal, axially extending splines by which drive is able to be supplied to the nut to cause its rotation relative to the housing.
The spindle of the headrest embodiment, from its drive end, has a main part in the form of an externally screw-threaded shank. The shank is received axially inwardly from the cable end of the nut by screw threaded engagement between the internal thread of the nut and the external thread of the spindle. At its cable end, the spindle is of bifurcated form to provide a pair of tabs which extend longitudinally from the shank part and which define a gap therebetween. The tabs are symmetrically disposed on opposite sides of the axis of the spindle shank, with the tabs parallel and facing each other. The spindle has a pulley which is mounted between the tabs, and which is rotatable on a pin extending through aligned holes in the tabs. The pulley has a diameter which exceeds the lateral dimensions of the spindle, while the pin is perpendicular to and intersects the spindle axis, such that a respective segment of the pulley is exposed each side of the spindle as viewed along the pin axis.
In the headrest embodiment, rotation of the nut in the housing enables the nut to advance or retract axially in housing between limits set by their respective threads in engagement. As the internal thread by which the nut is engaged with the spindle is of opposite hand to the external thread by which the nut is engaged with the thread of the housing, the spindle is able to advance from or retract into the nut as the nut respectively advances or retracts in the housing. Thus, the spindle is able to move axially with respect to the housing by a distance which is the sum of the distances through which the nut moves relative to the housing and the spindle moves relative to the nut.
With movement of the spindle between fully retracted and fully advanced positions, the pulley transverses a longitudinal portion of the housing in which the housing is unthreaded. However, in that portion, there is means for restraining the spindle against rotation relative to the housing as the spindle moves axially. This restraint is provided by the segment of the pulley exposed at each side of the spindle being located in a respective longitudinal groove or slot defined in or through the housing. Also, while the housing preferably is partly closed at the cable end, there is a continuation of each of these grooves or slots such that a flexible cable is able to be inserted through the cable end of the housing, along one groove or slot, and pass around the pulley and then back along the ot
Birch & Stewart Kolasch & Birch, LLP
Bucci David A.
Henderson's Industries Pty, Ltd.
Johnson Vicky A.
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