AU610955B2

AU610955B2 - Clamping device for clamping a vertical anode bar against a horizontal busbar of an electrolysis plant for producing aluminium

Info

Publication number: AU610955B2
Application number: AU26921/88A
Authority: AU
Inventors: Willem Christiaan Hammink
Original assignee: NKM NL KRAANBOUW
Current assignee: Bv Nederlandse Kraanbouw N K M Mij
Priority date: 1987-12-15
Filing date: 1988-12-15
Publication date: 1991-05-30
Anticipated expiration: 2008-12-15
Also published as: NL8703034A; CA1335980C; AU2692188A

Description

F j uw- N l -i irc S F Ref: 81517 FORM COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952 COMPLETE SPECIFICATION 6109

(ORIGINAL)

FOR OFFICE USE: Class Int Class o o' Complete Specifi dged: :epted: Published: Priority: Related Art: Name and Address of Applicant: B.V. Nederlandse Kraanbouw Maatschappij N K M 2003 RM Haarlem THE NETHERLANDS S Address for Service: Spruson Ferguson, Patent Attorneys Level 33 St Martins Tower, 31 Market Street Sydney, New South Wales, 2000, Australia Complete Specification for the invention entitled: Clamping Device for Clamping a Vertical Anode Bar Against a Horizontal Busbar of an Electrolysis Plant for Producing Aluminium The following statement is a full description best method of performing it known to me/us of this invention, including the 5845/3 &OC)42(Es OUR KRL: t~61bi &F CODE: 58920 1 /ile' 5845/2 Mi- q

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1 r Abstract cc C. I I 0 Cc C t C C CC C o c a0 0 0 00 00 0 0 00 00 0 0 00 00 T 0 Ct 0 0 0000 1 o C 0 01 00 C 0 A clamping device for clamping a vertical anode bar against a horizontal busbar of an electrolysis plant for producing aluminium comprises two levers 6) mounted pivotably with respect to each other, two projecting studs for supporting the levers on hooks (3) attached to the busbar and means for pivoting the levers 6) with respect to each other. In order to avoid the drawback of the clamping device being composed of many components and to provide the clamping device with a considerably simplified construction the levers constructed as castings, are provided with rotation surfaces 10 (11, 12) of cylindrical-segment shape which act on one another and which made the pivoting possible without a separate, material pivot shaft. One of the castings is provided with projections (25) which, in the operational state, act on an internal surface of cylindrical-segment shape, of the other casting with a round 15 surface (26).

NO 34853 short title:Clamping device for clamping a vertical anode bar against a horizontal busbar of an electrolysis plant for producing aluminium.

The invention relates to a clamping device for clamping a vertical anode bar against a horizontal busbar of an electrolysis plant for producing aluminium, comprising two levers mounted pivotably with respect to each other, two projecting studs for supporting the levers on hooks attached to the busbar, and means for pivoting the levers with respect to each other.

Such a clamping device is known from the US Patent Specification 3,627,670.

In the electrolytic production of aluminium, anodes attached 15 to the bottom end of anode bars are placed in the electrolytic o 00oo cells in a manner such that the distance between the underside of 00 1 Sa, the anodes and the bottom of the cells is maintained between fairly 0°00 narrow limits. The anode bars are clamped against a horizontal bar, 00 *0 the so-called busbar, by clamping devices. The busbar, the anode bars and the anodes form, together with the said clamping devices, o0 a the anode system which is moved downwards during operation in order 0 o0 not to allow the distance between the bottom of the anodes and the 0 o 0 base of the cell, which is reduced by anode wear, to become too o 2 large. When a busbar has reached the bottom end of its travel, it 0 25 has to be raised and the anode bars then have to be given a 0 0 different position on the busbar.

o 0 The clamped joint between the anode bars and the busbar has 0 0 0i 0 to be readily detachable. In fact, the clamping system with which S0° the anode bars are clamped to the busbar has two functions: to bring about a rigid mechanical joint and to maintain an electrical contact such that the voltage drop across the clamped joint is a minimum at the usual high current levels of 10,000 ampere or over.

A clamping pressure of 12,000 15,000 daN is necessary.

The known clamping device described above satisfies the requirements. The clamping pressure can be adequately controlled.

The operation of the clamping device is easy to automate.

In the known device, the said studs are formed by the e'nds of '12a section of shaft which extends through the clamping device. In order to pivot the levers with respect to each other, a threaded spindle is present whose head is fixed in the bush of a spanner on a drive mechanism. Said drive mechanism comprises a double clamp which is pressed into the closed position by a helical spring and which can grip securely the stud ends of the sh-aft.

A drawback of the known device is that it is composed of many components and forms a relatively expensive, complicated construction.

The object of the invention is to eliminate said drawback and to provide a clamping device described in the introduction with a considerably o simplified construction which nevertheless has the same efficient action as the known device.

0 00 There is disclosed herein clamping device adapted to clamp a vertical 0000 °0 o anode bar against a horizontal busbar, comprising: 0"0 first and second castings (levers) mounted casting pivotably with oo o respect to each other; 00 two studs projecting from the first casting beyond the sides of the anode bar, said studs being adapted to support the castings on hooks attached to the busbar; and o2D means for pivoting the levers with respect to each other; 0 0 00. the two castings being provided with rotational surfaces of cylindrical-segment shape which act on one another and which make pivoting CO' possible without a separate, material pivot shaft.

The clamping device known from the US Patent Specification 3,627,670 has a threaded spindle having two screw threads of opposite pitch and a nut o0 screwed onto each of said screw threads for pivoting the levers.

A preferred embodiment according to the invention is also appreciably simpler in this respect than the known clamping device. Proceeding from the fact that a threaded spindle is known for a clamping device, said preferred embodiment according to the invention is characterized in that the threaded spindle has a screw thread in only one direction and one single nut is screwed onto the threaded spindle.

The threaded spindle of the preferred embodiment acts on a concavely round cup of one of the levers with a convexly round end and extends through a cutout of the other lever.

In order to fix the nut easily, the preferred embodiment has a bush J'.d Whlch extends through the cutout and which is detachably clamped on the S_ oulders 3 3 of the said cutout by a screw having a collar.

The invention will now be explained in more detail by reference to the figures in which an exemplary embodiment is shown.

Figure 1 .ihows a perspective view of the clamping device in which a small proportion is imagined to be broken away, Figure 2 shows a perspective view of the components of the clamping device in the dismantled state.

Figure 3 shows a view and a partial section of the clamping device.

Figure 4 shows a perspective rear view of one of the levers of the device.

The clamping device shown clamps a vertical anode bar 1 with a controlled high pressure against a horizontal busbar 2. Attached 0 ooo 0 o to said busbar are two hooks 3 at some mutual distance from each 00oo 15 other by means of screws 4. The clamping device rests on said 0 00 scoo hooks.

0 5 0 0 00 The clamping device comprises two levers 5 and 6 in the form o of castings.

00 0 0o Lever 5 has two studs 7 which engage in said hooks 3 and a lug 8 with a cutout 9 at the end.

o0 G Lever 6 has a projecting part 10 with an external surface 11 00 0 a 0 of cylindrical--segment shape which, as Figure 3 show,., acts, in the 0 D00o oo installed state of the clamping device, on an internal surface 12, of cylindrical-segment shape, of the lever 5. The diameter of the 0 r 0 0 25 external surface 11 of the part 10 of cylindrical-segment shape 000(100 o o and the diameter of the internal surfa-e 12 of cylindrical-segment 01 shape are equal to each other so that the levers 5 and 6 are able 00 0 to rotate with respect to each other along said surfaces 11 and 12 o0o0oo o 0 with the imaginary centre line of the cylindrical surfaces 11 and 12 as axis of rotation.

A threaded spindle 13 has a convexly shaped pivot surface 14 at one end and a screw head 15 at the other end. In the assembled state of the clamping device, the threaded spindle 13 extends through the cutout 9 in the lug 8 of the lever 5. The convex surface 14 of the threaded spindle 13 acts on the concavely round internal surface of a replaceable platelet 16 which is mounted on the bottom of the cutout 17 at the free end of the lever 6.

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4 44 88 4 o 44 uo ~c 44 C Screwed onto the screw thread of the th:ceaded spindle 13 is a nut 18 which is fixed because a projecting bush 19 provided with a threaded hole extends through the cutout 9 at the end of the lug 8 and a collar 20 is clamped on the shoulders 22 of the cutout 9 by a screw 21 screwed into the hole of the bush 19 (Figure The bush 19 also prevents the nut 18 turning at the same time when the threaded spindle 13 is operated.

It will be clear that, by rotating the threaded spindle 13 in one direction or the other with a spanner acting on the screw head 15, the levers 5 and 6 are rotated in one direction or the other with respect to each other with the surfaces 11 and 12 of cyliindrical-segment shape as surfaces of rotation and therefore the centre line of the surfaces as imaginary axis of rotation. The clamping surfaces 23 and 24 respectively of the levers 5 and 6 are 15 able to act with a very high, but controlled pressure on the anode bar 1 and to clamp it onto the busbar 2.

A comparison of the Figures 1 and 2 makes it clear that the clamping device is composed of a small number of components which can be easily inserted in each other. In the assembled state, the part 10 of cylindrical-segment shape of the lever 6 is held in position by two projections 25 (Figure 4) which are provided with a surface 26, of cylindrical-segment shape, which acts on the internal surface 27, of cylindrical-segment shape, of part In order to dismantle the device according to Figure 3, the 25 screw 21 is unscrewed and the threaded spindle 13 is rotated outwards via the cutout 9, the nut 18 being taken out at the same time. The levers 5 and 6 can now be pivoted so far apart that the projections 25 emerge from the region of part 10. Near the cupshaped c\,tout, the lever 6 is provided with two projections 28 which able to prevent or impede the clamping device falling apart in the expanded state. By tipping the threaded spindle 13 through 90" it is possible to dismantle the spindle (and conversely, to assemble the spindle) with respect to the casting 6.

Various modifications and variants are possible within the scope of the invention. Essential to the inventive idva is that the rotary movement of the levers 5 and 6 with respect to each other ^KS^ becomes possible solely by shaping the lever castings without a separate, material pivot shaft being present. The supporting elements, constructed as studs 7, of the clamping device are completely separated from the imaginary axis of rotation of the levers. The threaded spindle 13 has only one screw thread and there is only one nut 18.

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Claims

1. Clamping device adapted to clamp a vertical anode bar against a horizontal busbar, comprising: first and second castings (levers) mounted casting pivotably with respect to each other; 'two studs projecting from the first casting beyond the sides of the anode bar, said studs being adapted to support the castings on hooks attached to the busbar; and means for pivoting the levcrs with respect to each other; the two castings being provided with rotational surfaces of o cylindrical-segment shape which act on one another and which make pivoting oo o possible without a separate, material pivot shaft. o o

2. Clamping device according to claim 1, wherein the second casting Soo is provided with projections, said projections being adapted to act on an o c internal surface of a cylindrical-segment shape provided in the first casting.

3. Clamping device according to claim 1 or 2, wherein the means for pivoting the levers with respect to each other comprises: a threaded spindle, said threaded spindle having a screw thread in ooooo only one direction; and 0 0 o0oo a nut adapted to be screwed onto the threaded spindle. 00 0

4. Clamping device according to claim 3, wherein the threaded ga 0"o spindle is provided with a substantially convex shaped end, said convex 0 0 shaped end being adapted to act on a substantially concave round cup provided in the first or second casting; 0- o said spindle being adapted to extend through a cutout provided in the casting alternate to the casting with which the cup is provided.

Clamping device according to claim 4, wherein the nut is provided with a bush which extends through the cutout and which is adapted to be detachably clamped on the shoulders of the cutout by a screw having a collar.

6. Clamping device substantially as hereinbefore described with reference to the accompanying drawings. DATED this FIRST day of MARCH 1991 B.V. Nederlandse Kraanbouw Maatschappij NKM Patent Attorneys for the Applicant SPRUSON FERGUSON i