Patent Application
20090039224
The present invention relates to equipment for use in mounting, supporting and displaying electronic devices. More particularly, the present invention is particularly adapted for use in adjustable extension arm apparatuses coupled to electronic devices such as flat panel displays, CRTs, keyboards, test equipment, laptop computers, tablet computers and other user devices.
It is often desirable to position user devices or equipment such as video displays, keyboards, mouse-type devices, etc. about a workspace or other location to give maximum comfort and ease of use to the user. For instance, such equipment can be placed on desks, tabletops, or upon other equipment such as personal computers or workstations.
One drawback to these configurations is the reduction in available workspace taken up by the equipment. Another drawback is the inability to place the equipment in a desired location. A further drawback is the potential for eye strain, neck strain and/or a cumulative trauma disorder such as carpel tunnel syndrome from poor placement of devices such as monitors and keyboards.
Different solutions have been provided in order to overcome these obstacles. For example, in one solution, a monitor stand or printer stand elevates the apparatus over other equipment on a desk. While this may free up workspace, it often places the equipment in an undesirable location or a fixed position. Another solution employs a mechanical extension arm to support the monitor. Extension arms free up workspace and allow users to place the equipment where it is wanted. One such extension arm is shown and described in U.S. Pat. No. 6,478,274, entitled “Arm Apparatus for Mounting Electronic Devices,” which is fully incorporated by reference herein. Another type of extension arm is shown and described in U.S. Pat. No. 6,409,134, entitled “Arm Apparatus for Mounting Electronic Devices with Cable Management System,” which is fully incorporated by reference herein. Other extension arms are shown and described in U.S. Pat. No. 7,100,880, entitled “Arm Apparatus for Mounting Electronic Devices with Cable Management System,” which is fully incorporated by reference herein.
a) illustrates a known extension arm 10 that can be connected at one end to a mounting assembly (not shown) and attached to a tilting device 12 at the other end for supporting a monitor 14 or other electronic user device. The mounting assembly may be of any desired configuration, and may be affixed to a piece of furniture such as a desk, a wall such as a slat wall, a section of an office cubicle, etc. A cable 16 is connected to the electronic device 14 at one end and has a plug or other connector 18 at the other end for connection to a power supply, networking hub or another electronic device such as a personal computer. While the electronic user device 14 is described below as a monitor such as a flat panel or other video display, the invention is not limited to use with such devices, and may be used with a wide variety of electrical and mechanical equipment, including non-powered equipment.
The extension arm 10 may be a conventional extension arm or any other suitable mounting device. Preferably, the extension arm 10 is one of the types fully described in above-referenced U.S. Pat. Nos. 6,409,134 and 6,478,274. As shown in
The first endcap 20 includes a housing attached to one end of the arm 22 by, for example, pins. A shaft 28 or other connection device is adapted for connection to the mounting assembly. The shaft 28 may be integrally molded with an endwall of the housing of the first endcap 20, and may be fabricated as a single part such as of aluminum. Alternatively, the shaft 28 may be securely attached to the housing of the first endcap 20.
The arm 22 is formed of an upper housing 22a and a lower housing 22b. The upper housing 22a and the lower housing 22b define a chamber therebetween containing, for example, a gas spring (not shown). The gas spring is adjustably mounted at one end within the first endcap 20 and at the other end to, for example, a ball stud mounted within the upper housing 22a. The cable 16 may be secured within the arm 22 as shown and described in U.S. Pat. No. 6,409,134. Alternatively, the arm 22 may include one or more external cable ties in order to secure the cable 16 of the electronic device 14 supported by the extension arm 10.
The second endcap 24 has a housing attached to the second end of the arm 22 by, for example, pins. A shaft (not shown) may extend out of the top of the housing of the second endcap 24 and connect to the forearm extension 26. The forearm extension 26 includes a body 30 having an interior channel, as well as a first end 32 and a second end 34. The forearm extension 26 may be rotatable about an axis of the first end 32.
The upper housing 22a, the lower housing 22b, the first endcap 20 and the second endcap 24 are configured so as to form an adjustable parallelogram. When configured, the housing of the first endcap 20 and the housing of the second endcap 24 point in opposite directions. The shape of the parallelogram is retained by the gas spring within the chamber of the arm 22. Generally, the gas spring is sized so as to have a fixed length until an upward or downward force is exerted at the second endcap 24 that exceeds the gas spring's designed resistance. Thus, the gas spring retains the parallelogram shape when the only force exerted at the second endcap 24 is the weight of the electronic device 14. However, the gas spring permits the parallelogram shape to be adjusted when a user pushes the electronic device 14, which is preferably coupled to the forearm extension 26 by means of the tilting device 12, up or down. The tilting device 12 can be directly connected to the endcap 24 or to the second end 34 of the forearm extension 26, and may be rotatable thereabout. The tilting device 12 may comprise known components, such as those shown and described in U.S. Pat. No. 6,505,988, the entire disclosure of which is hereby incorporated by reference herein.
The aforementioned extension arms are particularly beneficial when positioning and/or adjusting user equipment in a work environment. The user is able to quickly and efficiently position a video display terminal or other equipment while he or she is situated at a desk or lab table, for example. Notwithstanding the benefits of such extension arm devices, it is desirable to reduce manufacturing complexity, enhance durability and reduce the cost of manufacture. For instance, the endcaps of the extension arm may be placed under heavy loads and stresses. The materials used and the methods of fabricating the endcaps and associated components should be tailored to meet such needs to provide a quality product that can be easily made at reasonable cost. The present invention addresses these and other needs, as explained in detail herein.
In accordance with one embodiment of the present invention, a method of fabricating an adjustable extension arm assembly comprises forming a hollow tube structure having a first end, a second end, and at least one generally annular recess disposed about an exterior surface between the first and second ends of the tube structure. A mold is coupled to the hollow tube structure. A first endcap body is cast to form a unitary structure with the tube structure by applying liquid material to the mold so that the first endcap body mechanically bonds to the at least one generally annular recess about the exterior surface of the tube structure, And an adjustable extension arm member is fixed to the tube structure.
In one alternative, forming the hollow tube structure includes forming an exposed groove about the exterior surface of the tube structure and apart from the at least one generally annular recess. This may further comprise placing a thrust washer about a first portion of the tube structure and securing a snap ring to the exposed groove. In this case, the method may further comprise, prior to affixing the adjustable extension arm member to the tube structure, fitting a bushing into a bore of the adjustable extension arm member. Here, the bore of the adjustable extension arm member desirably includes a shoulder disposed along the interior surface of the bore remote from first and seconds ends thereof. Thus, fitting the bushing into the bore includes inserting the bushing into the bore until the bushing abuts the shoulder in this case.
In another alternative, the tube structure includes a bird mouth opening at the first end of the first endcap body. The first endcap body is cast to include an arcuate bridge member disposed over and conforming in shape to the generally arcuate bird mouth opening of the tube structure.
In accordance with another embodiment of the present invention, an extension arm assembly comprises a unitary endcap assembly and a forearm extension. The unitary endcap assembly includes a wrought tube structure having a first end, a second end, and at least one generally annular recess disposed about an exterior surface between the first and second ends of the tube structure. The tube structure includes a generally arcuate bird mouth opening at the first end thereof. The unitary endcap assembly also includes a cast first endcap body having a pair of sidewalls connected at one end by an arcuate bridge member and connected at another end by a second bridge member. The first endcap body has an opening at the first end and including at least one generally annular protrusion about an interior surface of the first end. The at least one generally annular protrusion is mechanically bonded to the at least one generally annular recess of the tube structure and the arcuate bridge member conforming in shape to the generally arcuate bird mouth opening of the tube structure. The forearm extension has a first end and a second end opposite the first end. The first end includes a bore therethrough. The forearm extension is affixed at the bore to the second end of tube structure opposite the first endcap body.
In one alternative, the forearm extension includes a shoulder disposed along the interior surface of the bore, with the shoulder being remote from either end of the bore. Here, the extension arm assembly further comprises a bushing disposed in the bore along a first side of the shoulder and between the interior surface of the bore and the exterior surface of the tube structure. Here, the extension arm assembly may further comprise a washer disposed about the tube structure and between the first end of the endcap body and the first end of the forearm extension. In another example, the extension arm assembly further comprises a thrust washer disposed about the tube structure adjacent a second side of the shoulder. In this case, a thrust load applied to the extension arm assembly is directly applied to the tube structure and is not directly applied to the bushing.
In another alternative, the extension arm assembly preferably further comprises first and second channel members as well as a second endcap assembly. The first channel member has a first end, a second end opposite the first end, and a pair of sidewalls extending from the first end to the second end. The second channel member has a first end, a second end opposite the first end, and a pair of sidewalls extending from the first end to the second end. The second endcap assembly has first and second ends, with the first end being adjustably coupled to the second ends of the first and second channel members. The first ends of the first and second channel members are adjustably coupled to the pair of sidewalls of the first endcap body. The generally arcuate bird mouth opening of the tube structure and the arcuate bridge member of the first endcap body provide clearance for the first ends of the first and second channel members to extend fully between a first position and a second position through a maximum range of at least about 90°. In a preferred example, the maximum range is between about 110° to 130°, although ranges greater than 130° or between 90° and 110° are also possible.
In accordance with yet another embodiment of the present invention, a method of fabricating an endcap device for use in an adjustable extension arm is provided. The method comprises forming a shaft member by machining a metal rod. The shaft member has a first end and a second end opposite the first end. The first end includes a connection region with a recessed area therealong, and the recessed area having a generally annular configuration. The method also comprises coupling a mold to the first end of the shaft member including the connection region. The method further comprises casting an endcap body using the mold to form a unitary structure with the shaft member by applying liquid metal to the mold. The endcap body is cast to include a first end, a second end opposite the first end, a pair of sidewalls disposed between the first and second ends and an opening therebetween along one side of the endcap body. The first end includes a receptacle therein. The receptacle includes an inner section, an outer section and a middle section therebetween. And the middle section has a generally annular protrusion mechanically bonded to the recessed area of the shaft member connection region.
In one alternative, the shaft member includes a generally cylindrical shaft extending from the first end of the endcap body, the shaft having an area moment of inertia of at least 0.09 in4. In another alternative, the shaft member is formed of wrought steel and the shaft has a stiffness of at least 1.45×106 lb-in2. In a further alternative, the generally annular configuration of the connection region recessed area includes radiused edges set at an angle of at least 15° with respect to one another.
In accordance with a another preferred embodiment of the present invention, an endcap assembly comprises a case endcap body and a shaft member. The cast endcap body has a first end, a second end opposite the first end, pair of sidewalls disposed between the first and second ends and an opening therebetween along one side of the endcap body. The first end includes a receptacle therein. The receptacle includes an inner section, an outer section and a middle section therebetween, with the middle section having a generally annular protrusion therealong. The shaft member has a connection region at a first end thereof mechanically bonded to the inner, middle and outer sections of the receptacle to form a unitary structure therewith. The connection region includes a generally annular recessed member coupled to the generally annular protrusion of the receptacle. The shaft member also includes a generally cylindrical shaft at a second end thereof remote from the first end of the endcap body. And the shaft has an area moment of inertia of at least 0.09 in4.
In one example, the shaft member is formed of wrought steel and the shaft has a stiffness of at least 1.45×106 lb-in2. In another example, the generally annular protrusion of the receptacle includes radiused edges that connect to the inner and outer sections. In this case, the radiused edges are set at an angle of at least 20° with respect to one another.
In accordance with yet another preferred embodiment of the present invention, an integral one-piece endcap for use with an extension arm assembly is provided. The endcap comprises an endcap body and a shaft member. The endcap body has a first end, a second end opposite the first end, a pair of sidewalls disposed between the first and second ends and an opening therebetween along one side of the endcap body. The shaft member has a first shaft section formed as an integral one-piece member with the first end of the endcap body and a second shaft section remote from the first end of the endcap body. The first shaft section includes a first set of cruciform members and the second shaft section including a second set of cruciform members. All corners and edges of the first and second sets of cruciform members are fully radiused to reduce stress concentrations therealong.
In one alternative, the first set of cruciform members has a longer length than the second set of cruciform members.
In accordance with a further embodiment of the present invention, an endcap for use with an extension arm assembly is provided. In this embodiment, the endcap comprises an endcap body having a first end, a second end opposite the first end, a pair of sidewalls disposed between the first and second ends and an opening therebetween along one side of the endcap body. The endcap also comprises shaft means fixedly secured with the first end of the endcap body.
The aspects, features and advantages of the present invention will be appreciated when considered with reference to the following description of preferred embodiments and accompanying figures. In describing the preferred embodiments of the invention illustrated in the figures, specific terminology will be used for the sake of clarity. However, the invention is not intended to be limited to the specific terms so selected, and it is to be understood that each term selected includes all technical equivalents that operate in a similar manner to accomplish a similar purpose. The drawings are not to scale. Any dimensions in the drawings, which are in inches, are merely exemplary.
As discussed above, the endcaps of an extension arm may be placed under heavy loads and stresses, especially when the extension arm is supporting a heavy user device, such as a large screen display. In this type of situation, the shaft of the endcap may bear the bulk of the load. In fact, it has been discovered that the shaft can be a critical failure point in the system. Thus, it is very important to ensure that the shaft can support expected loads.
In the past, endcap shafts have included configurations such as that shown U.S. Patent Publication No. 2006/0006297, entitled “Arm Apparatus with Reinforcement,” which illustrates the use of a cruciform-shaped endcap shaft. The 2006/0006297 patent publication, which is commonly assigned to the assignee of the present invention, is expressly incorporated by reference herein. FIGS. 11A, 11C, 11D and 11F of the 2006/0006297 patent publication illustrate an endcap having a cruciform-shaped shaft 154 having an “X” or cross-shaped cross section. See, for example,
Another known endcap shaft configuration is shown in
In the endcap 40 of
A critical point of failure of the extension arm is the junction between the upper shaft section 44 and the main body 41. Extending the length of the upper cruciform members 48 helps to reduce failure at this point. The inventor of the instant application has discovered several highly beneficial ways of improving endcap shaft design to increase the overall strength and stability of the endcap.
As seen in the perspective view of
Returning to
It is also desirable to increase the width of the cruciform members 110 and 112. For instance, while the width of the upper cruciform member 48 of
One result of these changes is to increase the area moment of inertia of the cruciform configuration. The moment of inertia is a property of a beam or other component that defines how well the material in the component resists stress. Beams tend to bend and resist stress about planes as defined by neutral axes. The axes go through the geometric center of symmetrical beams. Placing material as far as possible from the neutral axes produces a high moment of inertia and makes the beam stiff and strong. The moment of inertia is a square function of the distance from a neutral axis. Thus, doubling the distance from the neutral axis increases the moment of inertia by a factor of four. This permits a significant increase in beam strength and stiffness with small changes to the size of the beam.
Typically, the moment of inertia is calculated about two perpendicular neutral axes. For instance,
The example of
Of course, it should be understood that the dimensions in these and other examples throughout the specification are exemplary of the invention and variations in system specifications or manufacturing requirements may change particular dimensions. Thus, while an example may be given wherein the shaft is 1 inch in diameter, the cruciform arms are 0.3 inches in thickness, and radii of about 0.08 inches are used (or no radii at all), such parameters can be scaled up or down in size accordingly. For instance, if the shaft is reduced to 0.5 inches, the cruciform arms would desirably be reduced to 0.150 inches in thickness, and the radii would desirably be on the order of 0.04 inches or between about 0.25 and 0.75 inches (or no radii at all). Thus, in this instance, there would be a 1:1 scaling (either upward or downward) of the various component dimensions.
Of course, some minor variations in the relative scaling of different components may be expected; this is particularly true when material durability is taken into account. Thus in the 0.5 inch shaft diameter example, steel or an even more durable material may be required. This, in turn, may affect the requirements for moment of inertia. Therefore, it may be that the cruciform arms are chosen to have a thickness from a range of 0.15 to 0.25 or greater, and the radii may be chosen to be on the order of 0.04 to 0.07 or greater. Alternatively, more durable materials may relax the moment of inertia requirement, and thus the cruciform arm thickness may be chosen from the range of 0.085 to 0.15 or less and the radii may be chosen to be on the order of 0.02 to 0.04 or less (or no radii at all).
It is also preferable to increase the thickness of portions of the upper shaft section 106, for example top region 114 (see
Overall, the shaft 104 has an increased moment of inertia for the cruciform sections, as well as increased tensile and shear areas. And the radiused corners reduce water adhesion during the molding process. These critical features result in a substantially improved shaft configuration. This is particularly beneficial when the shaft 104 is integrally molded as a one-piece unit with the main body 102 of the endcap 100.
The shaft 104 may also include a receptacle 116 and a pair of recesses 118 along a bottom region 120 thereof. The receptacle 116 and the pair of recesses 118 may be utilized as part of an anti-loosening mechanism at the connection between the shaft 104 and a mounting assembly or other device (not shown), such as is described more fully in U.S. Patent Publication No. 2006/0266903, entitled “Tapered Mini Arm Having an Anti-Loosening Mechanism,” which is assigned to the assignee of the present invention and is hereby incorporated by reference herein.
In another preferred embodiment of the present invention, the shaft and the main body of the endcap are formed of different materials while both are cast as a single component.
The shaft 204 includes an upper section 206 and a lower section 208. Unlike the cruciform shaft 104 described above, neither section 206 nor section 208 has a cruciform configuration. While sections 206 and 208 may be of different diameters, both are preferably substantially cylindrical. The shaft 204, as with the shaft 104, may include a receptacle 210 and a pair of recesses 212 along a bottom region 120 thereof. The receptacle 210 and the pair of recesses 212 may be utilized as part of an anti-loosening mechanism at the connection between the shaft 204 and a mounting assembly or other device (not shown).
As can be seen in
As discussed above, the shaft 204 is preferably steel, such as wrought steel. The mechanical properties of wrought steel are more desirable for use as the shaft 204 than the mechanical properties of aluminum. Wrought steel will also consistently produce a stronger, stiffer part with a greater safety factor than the same part made with aluminum. The wrought steel is preferably machined to the desired shape before being coupled to the mold for casting of the endcap main body 202.
The configuration of the present embodiment provides a greatly increased moment of inertia over the length of the shaft as compared to shaft 42 of
The endcaps 100 and 200 are preferred embodiments of endcaps that are particularly beneficial when used to couple one end of an extension arm to a mounting assembly, which in turn secures the extension arm to a desk, wall, ceiling or other location. Referring back to
The process of fabricating the assembly 300 will now be described. The forearm extension 302 is illustrated in
Next, the pivot tube 306 is secured to the forearm extension 302. As shown in
The endcap 304 is shown in
While the aforementioned assembly process has been used successfully, it has certain disadvantages that make it undesirable in some situations. For instance, thrust loads go through the friction interference fit between the bushing and the tube casting. As noted above, it is disadvantageous to have the thrust load applied to the bushing 308. Also, the assembly process, including curing, takes a long time and delays fabrication of the finished product. The gluing operation cure time does not allow for one-piece manufacturing flow. Rather, manufacturing of the components must be done in batches.
Furthermore, epoxy and other glues are high-tack, very messy substances that must be kept off of all surfaces except for those specified. In addition, the assembly operation requires a gluing process that has clean part surfaces, greased part surfaces, and glued surfaced. These different types of prepared surfaces must be isolated from each other to prevent the product from being unusable and ruined. Glue technology requires strict process controls to assure strong, safe joints. There is no non-destructive post-assembly test to verify joint integrity. If the gluing is performed improperly, it may not be apparent post-assembly. Thus, a poorly glued part may be used in a final product, leaving the potential for failure of the product. This is a very undesirable situation.
Thus, applicant has developed a new endcap and forearm assembly 400 suitable for cable management, but which is assembled without the time consuming and difficult gluing process.
A preferred process of fabricating the assembly 400 will now be described. The forearm extension 402 is illustrated in
Prior to connection with the forearm assembly 402, the endcap body 404 and the tube 406 are fabricated.
The endcap body 404 desirably also includes one or more generally annular protrusions 432 about the first end which are formed when molten aluminum or other metal is cast around the tube 406. The tube 406 desirably comprises steel, such as wrought steel; however other metals or different materials meeting specified manufacturing requirements may also be used. The endcap body 404 is desirably formed by casting molten aluminum in a mold with the prefabricated tube 406. The molten aluminum flows through the mold and mechanically bonds to generally annular recesses 433, resulting in the protrusions 432 about the first end of the endcap 404. As shown in
Casting the endcap body 404 to the tube 406 avoids the use of (epoxy) glue. The tube 406 can be quickly and easily fabricated. Defects in the casting process are readily detectable, thereby avoiding hidden flaws that may occur with the gluing process. Also, should a defect exist, the endcap body 404 may be melted down and the material re-used, as opposed to the gluing process, thereby minimizing wasted material.
Once the assembly of the tube and endcap is complete, the washer 410 may be inserted around the tube 406 as shown in
While the instant example of assembly 400 includes components not required in the assembly 300, such as the thrust washer 414 and the snap ring 416, there are numerous advantages that make the assembly 400 highly beneficial. Because loads are applied to the tube 406 directly rather than through friction fitting of the bushing 408, slippage cannot occur between the bushing and the bore 422 of the forearm extension 402. Also, the casting and other assembly processes here entirely avoid the need for gluing. This saves a substantial amount of time, allowing each assembly 400 to be fabricated at one time, without the need to manufacture particular components in batches. As there is no glue used in the fabrication process, all of the problems associated with gluing are also avoided.
Once the assembly 400 has been fabricated, it can be connected to other components of an extension arm system.
As shown in
The maximum up and down angles are preferably on the order of at least about 45°. This provides an overall range of motion of approximately 90°. The exact range of motion may be slightly less or may be greater. For instance, in certain examples the maximum up or down angle may be more than 45°, such as 55° to 65°, and the maximum overall range is between about 110° to 130°. Such wide ranges are extremely advantageous, as they permits the user to position his or her display or other user device in the most ergonomic positions as desired.
The extension arm 450 includes an upper arm 452 and a lower arm 454. The specific configuration of the extension arm 450, including upper and lower arms 452 and 454, is not critical to the invention of the instant application. Numerous extension arm types may be used. By way of example only, any of the extension arms disclosed in U.S. Patent Publication Nos. 2006/0006297 or 2006/0266903, which are referenced above, may be employed. Regardless of the specific extension arm used, the bridge section 430 provides adequate clearance for the extension arm.
Thus, it can be seen that the assembly 400 can be easily and quickly fabricated, and that it permits full maneuverability when coupled to an extension arm.
Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. For instance, dimensions for various features of a given component may be scaled up or down, as may be required for manufacturing or for aesthetic purposes. All features for a component may be scaled equally or, as indicated above, certain parts may be of slightly different scale than others. By way of example, a shaft may be scaled down or up in size, such as by approximately 50%, while the cruciform arms and/or radii on the shaft may be scaled down or up in size by between 4°-60%.
Features of each embodiment of the instant invention may be freely used in any of the other embodiments herein. By way of example only, an extension arm may include a pair of endcaps, and each endcap may include the radiused cruciform configuration, the wrought steel cylindrical configuration, or one of each type. And the radiused cruciform and/or the wrought steel cylindrical configurations may be used with the cast tube coupled to a forearm extension. Furthermore, certain claims appended below may include steps of fabricating components. Unless otherwise expressly noted, the steps need not be performed in a given order.
