Support arm and method with variable counterbalance
A support arm includes an arm having a proximal arm pivot joint that provides a range of elevational rotation of the arm. The arm further includes a distal component mount. The support arm further includes a biasing device adapted to provide an increasing force with increasing displacement. A flexible element is coupled between the biasing device and the arm with a linkage therebetween. At least a portion of the flexible element forms a segment between the arm and the linkage. The segment is at an angle relative to the arm, and the angle varies during rotation of the arm. An arm end location of the segment is fixed in relation to the arm during rotation of the arm. A linkage end location of the segment changes in relation to the pivot joint during rotation of the arm.
This application relates to devices and methods for moveably supporting equipment. Specifically, but not by way of limitation, this application relates to devices and methods for supporting display screens such as flat panel display screens for use with personal computers.
BACKGROUNDIn many fields, it is useful to support equipment in such a way to make the position of the equipment adjustable. In particular, flat panel display screens (e.g., LCD screens, plasma screens and the like) are gaining popularity with consumers. It is desirable for users of flat panel display screens to position their screens, in orientations that are ergonomically correct, for instance at eye level.
Although examples of the present invention can be used with several different adjustment joints, an elevation joint is used as an example. An elevation adjustment is useful to provide flexibility for users of different heights. One common elevation adjustment includes an arm configuration with a joint between two arm portions. A user can move a distal arm portion along an arc by rotating the distal arm in relation to a base arm portion about an elevation joint.
It is inconvenient for the user if the equipment, such as the flat panel display, does not stay in the intended position. Unwanted motion can be caused by the elevation joint being too loose, with the equipment moving under its own weight. Additionally, sometimes the mechanism of the arm overcompensates or undercompensates for the weight of the display screen and/or the arm, and the arm undesirably moves out of the desired position on its own. Unwanted motion can also be caused by inadvertent bumping of the arm or supported equipment. Further, if the elevation joint moves an excessive amount, the supported equipment, such as the flat panel display, may become damaged by hitting a surface such as a desktop.
What is needed is a support arm that provides adjustability and retains the display screen in a desired orientation.
BRIEF DESCRIPTION OF THE DRAWINGS
In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and in which is shown, by way of illustration, specific embodiments in which the invention may be practiced. In the drawings, like numerals describe substantially similar components throughout the several views. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments may be utilized and structural, logical changes, etc. may be made without departing from the scope of the present invention.
As shown in
In another option, the housing 202 rides on casters 212 sized and shaped to facilitate movement of the chassis 200. The casters 212 permit movement of the display screen 102 into a variety of locations and the support arm 100 facilitates stable positioning of the display screen 102 into a variety of orientations for ease of viewing during use.
A biasing device 306, in one example, is coupled to the member 302B. The biasing device 306 provides a restoring force that increases with increased displacement of the device 306 (e.g., compression and/or extension). The biasing device 306 includes, but is not limited to, compression springs, tension springs, elastomeric materials and the like. The biasing device 306 is constructed with a material, such as steel, an elastomer and the like, that provides restoring force to retain the support arm 100 in a desired orientation. Optionally, the biasing device 306 includes springs and/or elastomeric material in combinations (e.g., in series, parallel, tension and compression springs together, and the like). As shown in
A flexible element 314, such as a filament, cable, belt and the like, extends between the members 302A, B. In one example, the flexible element 314 is coupled to the member 302B distal to the proximal mount 304. In another example, the flexible element 314 is coupled to the member 302A proximate to the distal component mount 106. As shown in
As shown in
As shown in
The arm end location 318 and the placement of the second pulley 316 along the member 302B are chosen so the angle Φ changes in a predetermined manner. The angle Φ changes in the predetermined manner to ensure the biasing device 306 provides a restoring force and corresponding moment that closely counterbalances the moment of the arm 100 and/or the display screen 102 (
In another option, the segment 315 of the flexible element 314 is coupled to the member 302A with a stop 320 sized and shaped to engage with the member 302A and substantially prevent movement of the segment 315 at the arm end location 318. In one example, the flexible element 314 is threaded through the member 302A with the stop 320 coupled to the element 314. The stop 320 has a larger profile than the element 314 and engages with the member 302A to couple the flexible element 314 to the member 302A. Optionally, the stop 320 includes, but is not limited to, a piece of plastic, metal and the like formed around the flexible element 314. In another option, the stop 320 includes a swaged portion of the flexible element 314 that presents a larger profile than the flexible element 314. In another example, the stop 320 is positionable along the member 302A while the support arm 100 is not being rotated. The stop 320 is positioned, for instance, within detents, grooves, spaced sockets and the like to selectively position an end of the segment 315 at varying arm end locations 318. The position of the arm end location 318 relative to the second pulley 316 correspondingly changes the length of the segment 315. Additionally, the position of the arm end location 318 relative to the second pulley determines how the angle Φ changes in the predetermined manner to alter the restoring force of the support arm 100 during rotation. Movement of the arm end location 318 toward the proximal mount 304 correspondingly increases the angle Φ throughout the travel of the support arm 100. As a result, the component of the restoring force of the biasing device 306 used to counterbalance the moment of the support arm 100 and/or the display screen 102 increases, as described below. Additionally, movement of the arm end location 318 toward the distal mount 106 increases the moment created by the restoring force because the moment arm 322 is correspondingly increased (also described below). Optionally, the arm end location 318 is chosen to optimize the component of the restoring force and the moment arm 322 that provide the moment to counterbalance the moment of the support arm 100 and/or the display screen 102.
The arm end location 318, where the flexible element 314 couples with the member 302A, is chosen to optimize the moment arm 1 m and the angle Φ and thereby provide a Msp that closely counterbalances the MW throughout rotation of the support arm 100. The angle Φ determines the component of the Fcable used in providing the Mps as shown in
In one example, a first arm end location 318 is chosen so Msp counterbalances the support arm 100 and a display screen 102 (
In operation, the support arm 100 is rotated around the proximal mount 304. The member 302A rotates around the pivot joint 307 and the member 302B similarly rotates with member 302A around an offset joint 309. Rotation of the support arm 100 from the position shown in
In another example, movement of the support arm 100 from a position, such as the position shown in
Optionally, the arm end location 318 of the segment 315 is changed to vary the moment arm 322 applied with the restoring force of the biasing device 306 to create the counterbalancing moment. Movement of the arm end location 318 also changes the angle Φ and thereby changes the component of the restoring force used in the counterbalancing moment. The arm end location 318, in one option, is chosen to optimize the moment arm 322 for the counterbalancing moment and also to optimize the component of the restoring force used to generate the moment.
Another example of the support arm 800 is shown in
As shown in
As described with the support arm 100, a biasing device 830, in one example, is coupled to the member 826B of the support arm 800. The biasing device 830 provides a restoring force that increases with increased displacement of the device 830 (e.g., compression and/or extension). The biasing device 830 includes, but is not limited to, compression springs, tension springs, elastomeric materials and the like. Optionally, the biasing device 830 includes springs and/or elastomeric material in combinations (e.g., in series, parallel, tension and compression springs together, and the like). As shown in
In another example, a second end 836 of the biasing device 830 is moveably coupled to a first pulley 838 to permit translational movement of at least the second end 836, as described below. Optionally, the first pulley 838 forms a linkage that supports a flexible element, described below. In another option, the first pulley 838 is positioned within the biasing device 830 (e.g., within the coils of a spring). The first pulley 838 is coupled with the basing device 830 by a bearing 840 extending between the pulley 838 and the second end 836 of the biasing device 830. A guide 842, in yet another option, extends from the second member 826B (e.g., the bracket 834) along the biasing device 830. In one example, the guide 842 is disposed within at least one of the bearing 840 and the biasing device 830. The guide 842 thereby substantially prevents lateral movement of the biasing device 830 during displacement of the device 830. The guide 842 is slidably coupled with the biasing device 830 and/or the bearing 840 and permits longitudinal displacement (e.g., contraction and extension) of the biasing device 830, as described below.
A flexible element 844, such as a filament, cable, belt and the like, extends between the members 826A, B. The flexible element 844 is constructed with, but not limited to, metal (e.g., steel), polymers, rope and the like. In one example, the flexible element 844 is coupled to the member 826B distal to the proximal mount 828. The flexible element 844 is coupled to the bracket 834, in another example. The flexible element 844 is coupled with, but not limited to, a fastener such as a lug 846, weld, pin and the like. In another example, the flexible element 844 is coupled to the member 826A proximate to the distal component mount 806.
As shown in
As described with somewhat similar components in the support arm 100, the flexible element 844 is coupled along the members 826A, B so the restoring force applied by the biasing device 830 to the support arm 800 increases as the moment of the support arm 800 increases, for instance while the support arm 100 is in a substantially horizontal intermediate position as shown in
As shown in
The arm end location 852 and the placement of the second pulley 848 along the member 826B are chosen so the angle Φ changes in a predetermined manner. The angle Φ changes in the predetermined manner to ensure the biasing device 830 provides a restoring force component and corresponding moment that closely counterbalances the moment of the arm 800 and/or the display screen 102 (
In another option, the segment 856 of the flexible element 844 is coupled to the member 826A with a stop 858 sized and shaped to engage with the member 826A and substantially prevent movement of the segment 856 at the arm end location 852. As described above for the stop 320, optionally, the stop 858 includes, but is not limited to, a piece of plastic, metal and the like formed around the flexible element 844. In another option, the stop 858 includes a swaged portion of the flexible element 844 that presents a larger profile than the flexible element 844. In one example, the flexible element 844 is threaded through a keeper 860 with the stop 858 coupled to the element 314. The keeper 860, in another example, is moveable along the member 826A, for instance along a rail 862. In still another example, the rail 862 includes a bolt, pin and the like sized and shaped to move along the member 826A and thereby move the arm end location 852 (e.g., the keeper 860).
The position of the arm end location 852 relative to the second pulley 848 correspondingly changes the length of the segment 856. Additionally, the position of the arm end location 852 relative to the second pulley 848 determines how the angle Φ changes in the predetermined manner to alter the restoring force of the support arm 800 during rotation. Movement of the arm end location 852 toward the proximal mount 828 correspondingly increases the angle Φ throughout the travel of the support arm 800. As a result, the component of the restoring force of the biasing device 830 used to counterbalance the moment of the support arm 800 and/or the display screen 102 increases. Additionally, movement of the arm end location 852 toward the distal mount 806 increases the moment created by the restoring force because the moment arm 864 is correspondingly increased. Optionally, the arm end location 852 is chosen to optimize the component of the restoring force and the moment arm 864 that provide the moment to counterbalance the moment of the support arm 800 and/or the display screen 102.
At 1204, a linkage is moveably coupled along the flexible element between first member 302A and the biasing device 306. At least a portion of the flexible element 314 forms a segment 315 between the first member 302A and the linkage and the segment 315 is at an angle relative to the first member 302A (e.g., angle Φ). The angle varies during rotation of the first member 302A. An arm end location 318 is fixed in relation to the first member 302A during rotation and a linkage end location 319 of the segment 315 changes in relation to the pivot joint 307 during rotation. In one example, the linkage includes at least one pulley 316 moveably coupled along the flexible element 314. The at least one pulley 316 is coupled to the second member 302B, in another example. In yet another example, the linkage includes cams, levers and the like adapted to assist in positioning the support arm 100 in a desired orientation.
Optionally, the support arm 100 includes an additional pulley 312 coupled between the biasing device 306 and the flexible element 314. The additional pulley 312 is moveably coupled to the flexible element 314 so the pulley 312 is in rolling communication with the flexible element 314.
CONCLUSIONUsing embodiments described above, a number of advantages are realized. One advantage includes a support arm that provides a moment that closely counterbalances the moment of the support arm and/or a display screen throughout the range of motion of the support arm. Because the support arm closely counterbalances the moment of the arm and/or the display screen, the arm remains in a desired orientation anywhere along the range of motion of the arm. Additionally, because the angle Φ decreases at a higher rate after at least passing the point of maximum moment of the support arm and/or the display screen (e.g., 0 degrees) the support arm attenuates the increased restoring force of the biasing device and closely matches the decreased moment of the support arm and display screen. Moreover, because the biasing device and the linkage (e.g., the flexible element) extend along the support arm members the support arm provides a narrow profile that takes up less space while retaining the support arm and/or the display screen in a desired orientation.
Although selected advantages are detailed above, the list is not intended to be exhaustive. Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that any arrangement which is calculated to achieve the same purpose may be substituted for the specific embodiment shown. This application is intended to cover any adaptations or variations of the present invention. It is to be understood that the above description is intended to be illustrative, and not restrictive. Combinations of the above embodiments, and other embodiments will be apparent to those of skill in the art upon reviewing the above description. The scope of the invention includes any other applications in which the above structures and fabrication methods are used.
Claims
1. A support arm, comprising:
- an arm having a proximal arm pivot joint to provide a range of elevational rotation of the arm, and a distal component mount;
- a biasing device sized and shaped to provide an increasing force with increasing displacement;
- a flexible element coupled between the biasing device and the arm with a linkage between the arm and the biasing device wherein at least a portion of the flexible element forms a segment between the arm and the linkage and the segment is at an angle relative to the arm, wherein the angle varies during rotation of the arm; and
- wherein an arm end location of the segment is fixed in relation to the arm during rotation of the arm, and a linkage end location of the segment change in relation to the pivot joint during rotation of the arm.
2. The support arm of claim 1, wherein the linkage includes at least one pulley.
3. The support arm of claim 1, wherein the arm includes a four bar linkage.
4. The support arm of claim 3, wherein the four bar linkage includes a second arm sized and shaped to correspondingly rotate with the arm, and another portion of the flexible element is coupled to the second arm.
5. The support arm of claim 1, wherein the flexible element includes a metal cable.
6. The support arm of claim 1, wherein the biasing device includes a tension spring.
7. The support arm of claim 1, wherein the biasing device includes a compression spring.
8. The support arm of claim 1, wherein the angle of the segment changes during rotation of the arm and the angle of the segment adjusts a moment applied to the arm by the biasing device throughout the range of elevational rotation of the arm.
9. The support arm of claim 1, wherein the biasing device is progressively displaced throughout the range of motion of the arm, and the angle of the segment changes at a higher rate at least when the arm rotates below horizontal to adjust a moment applied to the arm by the progressively displaced biasing device.
10. The support arm of claim 1, further comprising an additional pulley coupled with the biasing device to double displacement of the flexible element in relation to displacement of the biasing device.
11. A support arm, comprising:
- a four bar parallelogram linkage arm having a proximal arm pivot end to provide a range of elevational rotation of the arm, and a distal component mount;
- a spring coupled to an upper member of the four bar linkage parallelogram;
- a flexible element coupled between a bottom member of the four bar parallelogram linkage arm and the spring with a pulley between the bottom member and the spring wherein at least a portion of the flexible element forms a segment between the bottom member and the pulley, and the segment is at an angle relative to the bottom member, wherein the angle varies during rotation of the arm; and
- wherein an arm end of the segment is fixed in relation to the bottom member during rotation of the arm, and a tangent location of a pulley end of the segment changes in relation to the pivot end of the arm during rotation of the arm.
12. The support arm of claim 11, wherein the flexible element includes a metal cable.
13. The support arm of claim 11, wherein the arm end of the segment can be adjusted within a range of locations along the bottom member to a plurality of locations, wherein a selected location in the range remains fixed in relation to the bottom member during rotation of the arm.
14. The support arm of claim 11, wherein the angle varies during rotation of the arm between around 90 and −90 degrees.
15. The support arm of claim 11, further including an additional pulley coupled to the spring to double flexible element displacement in relation to spring displacement.
16. The support arm of claim 11, wherein the spring includes a compression spring.
17. The support arm of claim 11, wherein the spring is progressively displaced throughout the range of motion of the arm, and the angle of the segment changes at a higher rate at least when the arm rotates below horizontal to adjust a moment applied to the arm by the progressively displaced spring.
18. A system, comprising:
- a wheeled chassis;
- a support arm coupled to the wheeled chassis, the support arm including: an arm having a proximal arm pivot joint to provide a range of elevational rotation of the arm, and a distal component mount; a spring; a flexible element coupled between the arm and the spring with at least one pulley between the arm and the spring wherein at least a portion of the flexible element forms a segment between the arm and the at least one pulley, and the segment is at an angle relative to the arm, wherein the angle varies during rotation of the arm; wherein an arm end of the segment is fixed in relation to the arm during rotation of the arm, and a tangent location of a pulley end of the segment changes in relation to the pivot end of the arm during rotation of the arm;
- a display screen coupled to the distal component mount; and
- a processor unit in communication with the display screen.
19. The system of claim 18, wherein the arm includes a four bar linkage arm.
20. The system of claim 18, wherein the spring includes a compression spring.
21. The system of claim 18, further comprising an additional pulley coupled to the spring, and the additional pulley and the at least one pulley are adapted to double cable displacement in relation to spring displacement.
22. The system of claim 18, wherein the display screen includes a flat panel computer monitor.
23. The system of claim 18, wherein the processor unit is located adjacent to the wheeled chassis.
24. A method for making a support arm comprising:
- coupling a flexible element between a biasing device and a first member, and the first member includes a pivot joint, and the biasing device provides an increasing force with increasing displacement; and
- moveably coupling a linkage along the flexible element, and the linkage is between the first member and the biasing device, and at least a portion of the flexible element forms a segment between the first member and the linkage and the segment is at an angle relative to the first member, wherein the angle varies during rotation of the first member, and an arm end location of the segment is fixed in relation to the first member during rotation, and a linkage end location of the segment changes in relation to the pivot joint during rotation.
25. The method of claim 24, wherein moveably coupling the linkage along the flexible element includes moveably coupling at least one pulley along the flexible element.
26. The method of claim 25, further comprising coupling the at least one pulley to a second member, wherein the second member is adapted to correspondingly move with the first member.
27. The method of claim 25, further comprising coupling an additional pulley between the biasing device and the flexible element, and the additional pulley is moveably coupled to the flexible element.
28. The method of claim 24, further comprising coupling another portion of the flexible element to a second member, wherein the second member is adapted to correspondingly move with the first member.
29. The method of claim 24, further comprising coupling a portion of the biasing device to a second member, wherein the second member is adapted to correspondingly move with the first member.
Type: Application
Filed: Jun 29, 2005
Publication Date: Jan 4, 2007
Inventors: Saeb Asamarai (Columbia Heights, MN), Khalid Alzebdeh (Apple Valley, MN), Robert Fluhrer (Prior Lake, MN)
Application Number: 11/170,778
International Classification: A47F 5/00 (20060101);