Vertical motion pendant arm

Embodiments of the invention provide a vertical motion pendant arm for supporting an enclosure at a desired height. The vertical motion pendant arm can include an enclosure mounting assembly, a support mounting assembly, and one or more connectors. The vertical motion pendant arm can also include a drawbridge mechanism having a rotatable worm, a rotatable gear that engages the rotatable worm, one or more drawbridge arms coupled to the rotatable gear, and one or more gas springs coupled to the drawbridge arms and the connectors. The gas springs can provide a counterforce to the enclosure.

BACKGROUND

Pendant arms are used in the electronics industry for mounting and/or positioning of electrical enclosures that include, for example, operator interface controls. Pendant arms can move vertically and/or horizontally and can be mounted to walls, ceilings, machines, etc. The repositioning of conventional pendant arms can be accomplished in a variety of different ways, such as with threaded bolts and sliding members, mechanical springs and custom frictional disks, or multiple pivoting bars and counterweight assemblies.

SUMMARY

Some embodiments of the invention provide a vertical motion pendant arm for supporting an enclosure at a desired height. The vertical motion pendant arm can include an enclosure mounting assembly, a support mounting assembly, and one or more connectors that couple the enclosure mounting assembly to the support mounting assembly. The vertical motion pendant arm can also include a drawbridge mechanism having a rotatable worm, a rotatable gear that engages the rotatable worm, one or more drawbridge arms coupled to the rotatable gear, and one or more gas springs coupled to the drawbridge arms and the connectors. The gas springs can provide a counterforce to the enclosure.

DETAILED DESCRIPTION

FIG. 1illustrates a vertical motion pendant arm10according to one embodiment of the invention. The pendant arm10can include a support mounting assembly12, an enclosure mounting assembly14, a top connector16, a bottom connector18, and side panels20. The top connector16, the bottom connector18, and the side panels20can form a connection channel between the support mounting assembly12and the enclosure mounting assembly14.

In some embodiments, the pendant arm10can be used for mounting and adjusting the position of enclosures including small operator interface controls and/or instruments, such as human-machine interfaces (HMIs). The enclosure mounting assembly14can include an enclosure base22that can be coupled to an HMI. The support mounting assembly12can include a support base24that can be coupled to a support structure such as a machine, a wall, or a vertical pole. In some embodiments, the enclosure base22and/or the support base24can include additional attachments such as side-mount, top-mount, or pole-mount adaptors (not shown) to permit different coupling arrangements to the HMI and/or support structure. The support mounting assembly12and the enclosure mounting assembly14can each include a top cover26,28, a bottom cover30,32, and a side cover34,36, respectively. The top connector16, the bottom connector18, and the side panels20can be coupled to the support mounting assembly12and the enclosure mounting assembly14(e.g., at the side covers34,36) via fasteners38and can be rotatable about the fasteners38to allow vertical adjustment of the pendant arm10. In some embodiments, all components of the pendant arm10can be constructed of steel, such as a mild steel or type304stainless steel. In addition, the pendant arm10can maintain NEMA type 4, type 4X, and type 12 ratings, as well as IEC (International Electrotechnical Commission) IP66 enclosure ratings. The pendant arm10can withstand high-pressure washdowns and the side panels20can be removable for access to clean the interior of the connection channel.

As shown inFIG. 2, the pendant arm10can include a drawbridge mechanism40and one or more gas springs42to support the weight of an HMI coupled to the pendant arm10and stabilize the pendant arm10at different positions. The drawbridge mechanism40can be positioned within or adjacent to the support mounting assembly12and can be coupled to one end of the gas springs42. Another end of the gas springs42can be coupled to the top connector16via an attachment interface44. The gas springs42can be coupled to the attachment interface44via pins46and can be rotatable about the pins46.

FIGS. 3 and 4illustrate the drawbridge mechanism40according to one embodiment of the invention. The drawbridge mechanism40can include a vertical shaft48, a worm50, a gear52, drawbridge arms54, a bottom housing56, side housings58, and a top housing60. The bottom housing56, the side housings58, and the top housing60can be coupled together with fasteners62, as shown inFIGS. 3 and 4. The vertical shaft48can extend through the bottom housing56, the worm50, and the top housing60and can be secured on top by a nut64and a washer66. The worm50can surround the shaft48so that rotation of the shaft48causes rotation of the worm50. In some embodiments, the drawbridge mechanism40can be coupled to the support mounting assembly12via mounting fasteners68through a bottom portion of the side housings58, as shown inFIG. 2.

Spring mounts70can be coupled to or integral with the ends of each drawbridge arm54, as shown inFIGS. 3 and 4. The spring mounts70can permit attachment of one of the gas springs42to each drawbridge arm28, as shown inFIGS. 1 and 2, and can serve as pivot points for the gas springs42. When the pendant arm10is vertically adjusted, the gas springs42can provide a sufficient counterforce to support the weight of the load (e.g., the HMI coupled to the pendant arm10) and keep the pendant arm10at a desired height. For example, if a user raises or lowers the HMI to a specific height, the pendant arm10can keep the HMI at that desired height without the use of a locking device.

The shaft48can include an adjustment interface72to allow a user to rotate the worm50. The worm50can include teeth that engage teeth on the gear52. As a result, when the worm50is rotated, the gear52can also rotate. As shown inFIG. 4, the drawbridge arms54can be inserted through holes74of the side housings58and can include keyholes76to engage extensions78of the gear52. Accordingly, when the gear52is rotated, the drawbridge arms54can also rotate. The drawbridge arms54can be rotated to adjust the height of the pivot point of the gas springs42, which can change the counterforce capable of being provided by the gas springs42. More specifically, by adjusting the pivot point, the leverage that the gas springs42can have on a load can be adjusted. For example, as shown inFIG. 5, the drawbridge arms54can be at a maximum “up” position, which can be used for lighter loads.FIG. 6shows the drawbridge arms54at a maximum “down” position, which can be used for heavier loads.

As shown inFIGS. 3,4, and7, the adjustment interface72can be accessed from outside of the pendant arm10so that the user does not have to disassemble any components of the pendant arm10to adjust the drawbridge arms54. For example, the adjustment interface72can be rotated using a common tool, such as a socket wrench. The adjustable drawbridge arms54and the easily accessible adjustment interface72can allow the pendant arm10to have different load capabilities that are field-adjustable. In one embodiment, the pendant arm10can have a connection channel length of about 26 inches, can support loads between about 45 pounds and about 125 pounds, and can be vertically adjusted up to about 13 inches. In another embodiment, the pendant arm10can have a connection channel length of about 36 inches, can support loads between about 25 pounds and about 75 pounds, and can be vertically adjusted up to about 20 inches.

As shown inFIGS. 8-9, the pendant arm10can also include a tension adjustment device80. The tension adjustment device80can be located at the enclosure mounting assembly14. The bottom connector18can include an additional flap82on one side with a guide hole84. The flap82can be positioned between a series of plates86. The plates86can be coupled to the enclosure mounting assembly14via nuts88secured to protrusions90(a shown inFIG. 9) of the enclosure mounting assembly14. An adjustment knob92(as shown inFIGS. 7-9) can be positioned through the plates86and the guide hole84and tightened against a bracket94(as shown inFIG. 9). By tightening the adjustment knob92, the plates86can be forced toward each other against either side of the flap82.

The tension adjustment device80can be adjusted to provide a desired resistance to movement of the bottom connector18, as well as the entire pendant arm10. In one example, when the pendant arm10is adjusted to a specific height, the gas springs42can have a tendency to creep up or down. The tightened plates86against the flap82can provide enough tension to resist the forces of the gas springs42and keep the pendant arm10at the desired height. The tension adjustment device80can be kept tighter when the pendant arm is positioned in areas where more resistance is needed, such as rooms where vibrations occur. Unlike conventional lock-and-release devices, the tension adjustment device80does not need to be loosened to reposition the pendant arm10. In addition, the tension adjustment device80can provide a set range of motion for the pendant arm10by preventing the bottom connector18from moving when the adjustment knob92reaches either end of the guide hole84.

As shown inFIG. 10, the enclosure base22and the support base24can both be hollow and can have conduit attachments96and98, respectively. As also shown inFIG. 10, a flexible electrical conduit100can be routed through the support base24, the conduit attachment98, the conduit attachment96, and the enclosure base22in order to provide a continuous conduit pathway for cables or wires to the HMI with a single entry (e.g., at the support base24) and a single exit (e.g., at the enclosure base22). This continuous pathway can be Underwriters Laboratories® (UL)-rated from the single entry to the single exit. In one embodiment, the electrical conduit can be about 1.3 inches in diameter. In addition, in some embodiments, the pendant arm10can include support structures97and99for the conduit attachments96and98, as shown inFIGS. 2,5,6, and10.

The support mounting assembly12can rotate about the support base24via a rotation mechanism102(as shown inFIGS. 1,2,5-7, and10) through the bottom cover30to provide lateral adjustment of the pendant arm10. In addition, as shown inFIG. 11(andFIGS. 1,2,6-7, and10), the enclosure mounting assembly14can rotate about the enclosure base22via a rotation mechanism104through the bottom cover32to provide rotational adjustment of the HMI. Both bottom covers30,32can include holes106, for example, at 30-degree increments around the rotation mechanism. A peg108can be positioned in one of the holes106to engage a stop110when the rotation mechanism102,104is rotated, preventing a full 360-degree rotation of the rotation mechanism102,104(e.g., to prevent twisting of cables within the conduit100). Accordingly, in some embodiments, both the rotation mechanisms102,104can be rotated up to about 330 degrees. Additional screws112can be positioned in any of the holes106to set a desired range of rotation for the rotation mechanism102,104. Unlike conventional pendant arms, the screws112can be repositioned at any time to re-adjust rotation ranges without requiring disassembly of the pendant arm10. The support base24and the enclosure base22can be coupled to the rotation mechanisms102,104via fasteners114, as shown inFIG. 7.

FIGS. 12 and 13illustrate the pendant arm10according to another embodiment of the invention. As shown inFIG. 12, the attachment interface44can include a hose guide116to support the conduit (not shown). In addition, the drawbridge mechanism40ofFIGS. 12 and 13can include an integrated housing118and the worm50can be positioned in front of the gear52.FIG. 12also illustrates an HMI120coupled to the enclosure base22.