Patent Application
20100123393
The technical field of this disclosure is high intensity discharge (HID) lamps, particularly, an HID lamp with a canted arc tube.
In the majority of HID lamps, the arc tube is arranged in the outer envelope aligned with the lamp axis. The outer envelope has a bulbous portion surrounding the arc tube, and an elongate neck portion extending from the bulbous portion. The arc tube is normally supported in the lamp envelope by a support frame fixed to rigid current-supply conductors extending from the lamp stem through the neck portion of the outer envelope.
The burning orientation of the arc tube in HID lamps affects the efficiency of the lamps. It has been found that a vertical burning position of the arc tube is most efficient, followed by a horizontal burning position. However, in certain lamp applications, it is not practicable to orient the outer bulb in a horizontal or vertical position. For example, in portable light towers for illuminating sports playing fields, the design and position of the reflector for illuminating the playing field limits the orientation of the outer bulb to a base-up orientation with the bulb axis between the vertical and horizontal. Thus, such luminaires would support the arc tube at an angle which is less efficient than the preferred vertical or horizontal burning positions. As a result, prior art lamps having an arc tube aligned with the lamp axis do not provide optimum light distribution or efficiency when operated in such luminaires.
One solution has been to provide a lamp in which the arc tube is supported in the outer envelope at a predetermined angle with respect to the lamp axis. For sports lighting applications, the arc tube is canted such that it would be in a horizontal burning position when secured in a luminaire. However, in lamps having an arc tube canted more than only a few degrees from the lamp axis, the configuration of the frame for supporting the arc tube has prevented the insertion of the frame and arc tube through the elongate neck portion of the standard bulged-tube (BT) outer envelope.
The present generation of HID lamps with canted arc tubes requires complex configurations and/or assembly methods. One approach has been to sever the elongate neck portion from the outer envelope, insert the arc tube assembly into the outer envelope, and reattach the elongate neck portion to the outer envelope. This adds steps to and increases the complexity of the assembly process. Another approach has been to provide rotary joints in an articulated frame holding the arc tube, so that the arc tube assembly is in a generally linear configuration when inserted through the elongate neck portion into the outer envelope. Once in the outer envelope, the articulated portions of the frame are rotated at the rotary joints to achieve the canted arc tube, and locking the rotary joints are locked in place. Unfortunately, the rotary joints present a number of problems. The rotary joints increase the resistance of the frame, reducing lamp efficiency. A shunt strap may be required in parallel with the rotary joint to assure sufficient current carrying capacity. Installation of the rotary joints and shunt straps in the frame increases the number of fabrication steps, increasing costs. Rotary joints can also increase the rejection rate for defective lamps, since the rotary joint may not lock properly. The rotary joints also increase the number of parts that must be stocked and handled.
It would be desirable to have an HID lamp with a canted arc tube that would overcome the above disadvantages.
One aspect of the present invention provides a high intensity discharge (HID) lamp including an outer envelope having a neck portion and a lamp axis; a frame having a first frame section, a second frame section, a third frame section, the first frame section being pivotably connected to the second frame section in a first connection, and the second frame section being pivotably connected to the third frame section in a second connection; and an arc tube having an arc tube axis, the arc tube being attached to the second frame section. At least one of the first connection and the second connection is a deformable connector paired with a rotary joint; and the arc tube axis forms a predetermined angle with the lamp axis when the frame is in a final configuration in the outer envelope.
Another aspect of the present invention provides a high intensity discharge (HID) lamp including an outer envelope having a neck portion and a lamp axis; a frame having a first frame section, a second frame section, a third frame section, a first pair of rotary joints pivotably connecting the first frame section and the second frame section, a second pair of rotary joints pivotably connecting the second frame section and the third frame section; and an arc tube having an arc tube axis, the arc tube being attached to the frame between the first pair of rotary joints and the second pair of rotary joints. The first pair of rotary joints and the second pair of rotary joints are selected from the group consisting of one piece rotary joints, pinned rotary joints, and tabbed rotary joints; and the arc tube axis forms a predetermined angle with the lamp axis when the frame is in a final configuration in the outer envelope.
Another aspect of the present invention provides a high intensity discharge lamp including an outer envelope having a neck portion and a lamp axis; a fixed frame having a first bend and a second bend opposite the first bend; and an arc tube having an arc tube axis, the arc tube being attached to the fixed frame between the first bend and the second bend. The fixed frame is so dimensioned as to be insertable through the neck portion; and the arc tube axis forms a predetermined angle with the lamp axis when the fixed frame is in a final configuration in the outer envelope.
The foregoing and other features and advantages of the invention will become further apparent from the following detailed description of the presently preferred embodiments, read in conjunction with the accompanying drawings. The detailed description and drawings are merely illustrative of the invention, rather than limiting the scope of the invention being defined by the appended claims and equivalents thereof.
Referring to
The frame 9 has three frame sections 9a-9c which are pivotable with respect to each other and connected with rotary joints. The rotary joints are lockable to maintain the predetermined angle between the arc tube 4 and the lamp axis 32 once the frame 9 is installed in the outer envelope 1 in the final configuration. The rotary joints are also electrically conductive. The first frame section 9a includes the current-supply conductors 13, 14. The second frame section 9b includes one rigid conductor 15b which extends along one side of the arc tube 4, an upper short conductor 16b, and a lower short conductor 16a. Each of the short conductors 16a, 16b are adjacent one of the pinch seals 5 of the arc tube 4 and are secured thereon by metallic bands 17. A quartz glass tube 18 encloses the rigid conductor 15b and electrically insulates the rigid conductor 15b from the opposing upper short conductor 16b. The first frame section 9a is pivotably connected to the second frame section 9b with the connection of the current-supply conductor 13 to the rigid conductor 15b through rotary joint 20 and the connection of the current-supply conductor 14 to the lower short conductor 16a through rotary joint 21. The third frame section 9c is a single generally U-shaped rigid wire including legs 15c, 16c connected with crossbar 36. The third frame section 9c is pivotably connected to the second frame section 9b through the pair of rotary joints 22, 23 with the connection of the leg 15c to the rigid conductor 15b through the rotary joint 22 and the connection of the leg 16c to the upper short conductor 16b through the rotary joint 23. In one embodiment, a shunt strap can be connected in parallel with one or more of the rotary joints as desired to assure current carrying capacity.
Resilient bars maintain the position of the frame 9 in the outer envelope 1. Lower resilient bars 38, 40 connected to the respective current-supply conductors 13, 14 of the first frame section 9a contact the inside surface of the neck portion 34 of the outer envelope 1. Upper resilient bars 42, 44 connected to the respective legs 15c, 16c of the third frame section 9c contact the inside surface of protruding domed portion 1c of the outer envelope 1.
The electrical connection to the arc tube 4 is provided through the frame 9 and the rotary joints. The path from the lamp cap 2 to the discharge electrode 6b includes the current-supply conductor 14 and metallic strap 8b connected to the discharge electrode 6b. The starting electrode 6c is connected to the current-supply conductor 14 through a resistor and bimetal switch (not shown). The path from the lamp cap 2 to the discharge electrode 6a includes the current-supply conductor 13, rotary joint 20, rigid conductor 15b, and metallic strap 8a connected to the discharge electrode 6a. In one embodiment, an electrical shunt (not shown) can be connected across the rotary joint 20 between the current-supply conductor 13 and the rigid conductor 15b to ensure current flow to the discharge electrode 6a.
During manufacture, the three frame sections 9a-9c of the frame 9 are aligned so that the frame 9 can pass through the neck portion 34 of the outer envelope 1. The rotary joints 20-23 allow a larger angle between frame sections than the angle in the final configuration. When the upper resilient bars 42, 44 have been placed in the domed portion 1c of the outer envelope 1, the three frame sections 9a-9c can be rotated relative to each other until the rotary joints 20-23 lock, fixing the predetermined angle between the arc tube 4 and the lamp axis 32.
During manufacture of the HID lamp, the arc tube assembly is placed through the neck portion of the outer envelope with the rotary joint 50 in the unlocked configuration of
During manufacture of the HID lamp, the arc tube assembly is placed through the neck portion of the outer envelope with the rotary joint 70 in the unlocked configuration and rotated into the locked configuration of
Those skilled in the art will appreciate that the first disk 72 and the second disk 82 can form additional locking holes as desired for a particular application. The additional locking holes can be located across the connection hole 74 from the first locking hole 78 and the second locking hole 88. The first connector/frame 96 is bent to form a tip which passes through the additional locking holes when the additional locking holes are aligned, further locking the rotary joint 70 in the permanently locked configuration in addition to the locking provided by the tip 94, the second locking hole 88, and the first locking hole 78.
During manufacture of the HID lamp, the arc tube assembly is placed through the neck portion of the outer envelope with the rotary joint 100 in the unlocked configuration of
Those skilled in the art will appreciate that the rotary joints described above in
Referring to
During manufacture, the three frame sections 9a-9c of the frame 9 are aligned so that the frame 9 can pass through the neck portion 34 of the outer envelope 1. The rotary joints 21, 23 and the deformable connectors 130, 132 allow a larger angle between frame sections than the angle in the final configuration. When the upper resilient bars 42, 44 have been placed in the domed portion 1c of the outer envelope 1, the three frame sections 9a-9c can be rotated relative to each other to lock the rotary joints 21, 23 and bend the deformable connectors 130, 132, fixing the predetermined angle between the arc tube 4 and the lamp axis 32.
The arc tube assembly 170 includes a fixed frame 172 and an arc tube 190. The fixed frame 172 has a first frame section 174, a second frame section 176, and a third frame section 178, with a first bend 180 between the first frame section 174 and the second frame section 176, and a second bend 182 between the second frame section 176 and the third frame section 178. The arc tube 190 is attached to the fixed frame 172 between the first bend 180 and the second bend 182. The first bend 180 is opposite the second bend 182, i.e., the first bend 180 and the second bend 182 open in opposite directions. In this embodiment, the first bend 180 and the second bend 182 are the clearance points which contact the inside of the neck portion of the outer envelope when the arc tube assembly 170 is inserted through the neck portion. Clearance points as defined herein are the points of the arc tube assembly which contact the inside of the neck portion of the outer envelope when the arc tube assembly is inserted through the neck portion. The arc tube assembly 170 is narrow at the clearance points so that the arc tube assembly 170 has room to rotate through the neck portion. The arc tube 190 has an arc tube axis 192, which forms a predetermined angle θ to the lamp axis 194 when the fixed frame 172 is in a final configuration in the outer envelope. In one example, the predetermined angle is about 30 degrees.
Referring to
Referring to
Those skilled in the art will appreciate that the dimensions of the arc tube assembly can be selected to suit a particular application, so that the arc tube assembly is insertable through the neck portion of the outer envelope. The narrower the clearance point in contact with the inside of the neck portion when the arc tube assembly is being rotated through the neck portion, the more acute the bend can be. Similarly, the narrower the portion of the fixed frame and/or arc tube in contact with the neck entrance or neck exit when the arc tube assembly is being rotated through the neck portion, the more acute the bend can be. In one embodiment, the bend is offset from the arc tube axis, so that the arc tube pinch seal is the clearance point. In another embodiment, the first frame section and/or third frame section include curves and/or steps to allow more room between the frame section and the neck entrance or neck exit when the arc tube assembly is being rotated through the neck portion.
The HID lamp 230 includes an outer envelope 240 and an arc tube assembly 250 located within the outer envelope 240. The outer envelope 240 having a lamp axis 290 includes a globe portion 242, a neck portion 244, and a domed portion 246. A lamp cap 248 provides the electrical connection to the HID lamp 230. The arc tube assembly 250 includes a fixed frame 252, and an arc tube 270 having an arc tube axis 292. The fixed frame 252 has a first frame section 254, a second frame section 256, and a third frame section 258, with a first bend 260 between the first frame section 254 and the second frame section 256, and a second bend 262 between the second frame section 256 and the third frame section 258. In this example, the second frame section 256 is enclosed in an insulating tube. The first frame section 254 includes a number of steps to allow the rigid arc tube assembly 250 to pass through the neck portion 244 and achieve the desired angle with the lamp axis 290. Those skilled in the art will appreciate that the first frame section 254 and/or the third frame section 258 can include steps and/or curves to increase the maneuverability of the fixed frame 252 through the neck portion 244, as long as the angle between the arc tube axis 292 and the lamp axis 290 is the desired predetermined angle. In one embodiment, the predetermined angle between the arc tube axis 292 and the lamp axis 290 in the final configuration of the HID lamp 230 is about 30 degrees. A leaf spring 272 fixed to or pivotably attached about the third frame section 258 maintains the position of the arc tube assembly 250 in the domed portion 246. Leaf springs 274 attached to the first frame section 254 maintain the position of the arc tube assembly 250 in the neck portion 244.
In this embodiment, one or both of the first bend 260 and the second bend 262 are the clearance points during installation of the arc tube assembly 250 in the outer envelope 240. The second frame section 256 is longer than the arc tube 270, so the first bend 260 and the second bend 262 extend beyond the arc tube 270. The widths of the first bend 260 and the second bend 262 are selected so the fixed frame 252 is insertable through the neck portion 244. Those skilled in the art will appreciate that the one or both of the first bend 260 and the second bend 262 can be rigid to maintain a constant angle when inserted through the neck portion 244, i.e., the angle of the bend remains constant and does not increase or decrease. In another embodiment, one or both of the first bend 260 and the second bend 262 can be resilient, so that the angle of the bend changes slightly, such as increasing or decreasing, when passing through the neck portion 244 and returns to the original bend angle once inside the outer envelope 240.
The HID lamp 330 includes an outer envelope 340 and an arc tube assembly 350 located within the outer envelope 340. The outer envelope 340 includes a globe portion 342, a neck portion 344, and a domed portion 346. The arc tube assembly 350 includes a fixed frame 352 and an arc tube 370. The fixed frame 352 has a first frame section 354, a second frame section 356, and a third frame section 358, with a first bend 360 between the first frame section 354 and the second frame section 356, and a second bend 362 between the second frame section 356 and the third frame section 358. In one embodiment, the predetermined angle between the arc tube axis 392 and the lamp axis 390 in the final configuration of the HID lamp 330 is about 30 degrees. In this example, the second frame section 356 is enclosed in an insulating tube and is at a desired angle to the arc tube axis 392. Angling the second frame section 356 off the arc tube axis 392 can be used to reduce shadowing of the arc tube 370 by the second frame section 356.
A leaf spring 372 attached to the third frame section 358 is receivable in and maintains the position of the arc tube assembly 350 in the domed portion 346. The leaf spring 372 is pivotably attached about the end portion 359 of the third frame section 358 so that the leaf spring 372 can follow the contour of the interior of the outer envelope 340 as the leaf spring 372 enters the globe portion 342 from the neck portion 344 of the outer envelope 340 when the arc tube assembly 350 is being inserted into the outer envelope 340. U-shaped springs 374 attached to the first frame section 354 of the fixed frame 352 maintain the position of the arc tube assembly 350 in the neck portion 344. The U-shaped springs 374 can be aligned to spring against the neck portion 344. The arc tube 370 includes a first pinch seal 382 near the first bend 360 and a second pinch seal 386 near the second bend 362. The arc tube 370 is attached to the fixed frame 352 with metallic bands 380, 384.
In this embodiment, the bends 360, 362 are located off the arc lamp axis 392, so one or both of the pinch seals 382, 386 at the ends of the arc tube 370 are the clearance points during installation of the arc tube assembly 350 in the outer envelope 340. The bends 360, 362 are nearer the lamp axis 390 than their respective pinch seals 382, 386. The widths of the pinch seals 382, 386 determine the dimensions of the fixed frame 352 that can be inserted through the neck portion 344.
Those skilled in the art will appreciate that the arc tube assembly can optionally be flexible and/or include flexible portions as desired for a particular purpose. In one example, one or more of the bends in the fixed frame can be resilient so the angle of the bend opens while the bend is the clearance point passing through the neck portion of the outer envelope. In another example, the one or more of the frame sections can be resilient so arc tube assembly becomes flatter, i.e., more linear, as the frame section passes through the neck portion of the outer envelope. Lubricants and/or coatings can also be applied to the outer envelope and/or the arc tube assembly so that the arc tube assembly slides more easily through the neck portion. In one example, the interior of the outer envelope can be coated with AP-5 glass coating.
While the embodiments of the invention disclosed herein are presently considered to be preferred, various changes and modifications can be made without departing from the scope of the invention. The scope of the invention is indicated in the appended claims, and all changes that come within the meaning and range of equivalents are intended to be embraced therein.
