Method and apparatus for filling electrical energy storage devices

A multi-station machine for filling storage batteries has an unloading station, a loading station and a filling station. At the unloading station, a filled battery case is removed from a pivotally mounted cradle assembly including an acid container. At the loading station, adjacent the unloading station, the battery case is loaded in the cradle assembly in a vertical orientation and then tilted to and latched in an angular orientation. At the filling station, the battery case and acid container are further tilted to a horizontal orientation, the container is filled with acid and then returned to the tilted and latched orientation. When all of the cradle assemblies are filled with battery cases and acid container are filled with acid, the cradle assemblies, are spun at a speed sufficient to rotate the assemblies to a more tilted orientation to cause centrifugally induced flow of the acid into the battery case while simultaneously unlatching the cradle assemblies. The machine speed is slowed and the cradle assemblies return to the vertical orientation for unloading.

TECHNICAL FIELD
 This invention relates to electrical energy storage devices such as lead
 acid batteries and more particularly to a method and apparatus for filling
 such devices.
 BACKGROUND OF THE INVENTION
 Lead-acid batteries have a casing with a plurality of internal, paste
 filled, grid plates and separators that are submerged in acid. The grid
 plates and separators are tightly compacted elements. During the
 manufacture of the batteries it is necessary to fill the case with the
 acid after the grid plates are installed. It is imperative to completely
 fill the case and also to fully saturate the separators. This can be a
 time consuming operation which increases the cost of production as the
 fill time increases, particularly when the separators are made with
 absorbent glass mat material.
 Many methods have been considered or undertaken in an effort to reduce the
 fill time. It has been proposed to roll the battery case to lie on one
 side and then partially submerge the case in an acid bath. This method
 results in an unknown quantity of acid fill and is too time consuming.
 Another method that has been considered also lays the battery case on the
 side and attaches a manifold to ports on the "top" so that acid can be
 metered into the case through the manifold. This method is also very time
 consuming and total saturation of the separators is virtually impossible.
 Yet another method that has been considered includes applying a vacuum to
 the case to evacuate the air and introduce acid into the interior of the
 case. This method results in dry spot in the separators and acid damage to
 the vacuum equipment. Still another method used a pulse vacuum to evacuate
 the air while acid is introduced through the bottom of the case. The case
 could not be reliably sealed following the fill operation. A further
 method included pouring acid directly into the top of the battery case.
 This method results in trapped air, which creates dry spots in the
 separators, insufficient acid fill and excessive fill time.
 SUMMARY OF THE INVENTION
 It is an object of the present invention to provide an improved method and
 apparatus for filling electrical energy storage devices.
 In one aspect of the present invention, a method of centrifugal filling
 batteries is employed. In another aspect of the present invention, a
 battery is loaded into a filling machine in a vertical attitude beneath an
 acid container. In yet another aspect of the present invention, the
 battery case and acid container are pivoted to and latched in an angular
 orientation.
 In still another aspect of the present invention, the battery case and acid
 container are rotated to a speed sufficient to cause further pivoting of
 the assembly to open a flow path for the acid to fill the battery case. In
 yet still another aspect of the present invention, a centrifugally
 responsive latch mechanism released the assembly to return to the vertical
 positioning when the rotation is discontinued after the battery case is
 filled. In a further aspect of the present invention, an unloading
 station, a loading station and a filling station are provided in
 sequential order on a multi-station machine. In yet a further aspect of
 the invention, the battery case and acid container assembly is tilted to
 the horizontal position in the filling station.

DESCRIPTION OF AN EXEMPLARY EMBODIMENT
 Referring to the drawings wherein like characters represent the same or
 corresponding parts throughout the several views there is seen in FIGS. 1
 and 2, a battery filling machine 10 including a work table 12 in the form
 of a plate or disc in which is formed a plurality of stations 14. In the
 embodiment shown, eighteen stations are illustrated which permits twenty
 degrees of spacing between the stations. The work table 12 is drivingly
 connected with a shaft of spindle or shaft 16 through a hub 18. The hub 18
 is mounted for rotary and vertical support on a stanchion 20 by a tapered
 roller bearing 22.
 The spindle 16 is drivingly connected with a conventional electric motor 24
 through a conventional gear box 26. Conventional motor controls, not
 shown, control the speed of the motor between zero and approximately three
 hundred (300) rpm. The speed of the motor is dependent on the radius at
 which the stations are formed. The stanchion is mounted on three
 equiangularly spaced legs 28. The legs 28 are secured to a base plate 30
 that has a plurality of leveling feet 32.
 Each station 14 has two trunnion support openings 34 in which a cradle
 assembly 46 is positioned as shown at station 14A in FIG. 1. A trunnion 38
 is secured in each opening 34 when the assembly 46 is loaded on the work
 table 12. As shown in FIG. 12, the trunnions 38 are secured to the work
 table 12 by threaded fasteners 40. Each trunnion 38 has an opening 42 in
 which a shaft 44 is rotatably mounted. The shaft 44 is a component of the
 cradle assembly 46 in which an acid container 64 and gasket 36 are
 secured. One of the trunnions 38A has a latch assembly 48 secured thereto,
 as seen in FIGS. 1, 2, 3, 4 and 6. The latch assembly 48 includes a
 bracket 50 and a latch lever 52 pivotally mounted on the bracket 48 with a
 pin 54.
 As previewed in the preceding paragraph, when a general reference is made
 to a plurality of like components, the general numerical designation, such
 as station 14, will be used. When a specific reference is made to one of
 the plurality of components, an alpha-numeric designation, such as station
 14A, will be used.
 The cradle assembly 46 has a pair of spaced side walls 56 to which the
 shafts 44 are secured. And upper plate 58 and a lower plate 60 are secured
 to the side walls 56. A spring biased plate 62 is urged against the acid
 container 64 by springs 66 compressed between the upper late 58 and a
 bracket secured to the plate 62. The springs 66 urge the cam plate 62
 against the acid container 64. A battery case 68 is secured to the acid
 container 64 with the gasket 36 squeezed therebetween by the spring
 pressure created between the plate 62 and the lower plate 60. A pair of
 lifting rods 70 are provided to compress the springs 66 and lift the acid
 container 64 and gasket 36 when loading and unloading of the battery case
 68 to or from the cradle assembly 46 is undertaken.
 Each shaft 44A has a lever 72 and cam wheel 74 attached thereto by
 fasteners 76. A roller 78 is rotatably mounted on the lever 72 through a
 bracket 80. Pivoting of the lever 72 will cause the cradle assembly 46 to
 rotate relative to the work table 12 while the trunnions 38 and the
 bracket 50 of the latch assembly 48 are fixed relative to the work table
 12. The can wheel 74 has a notch portion 82 that is engaged by an end 84
 of the latch lever 52 when the cradle assembly 46 has been rotated through
 a predetermined angle, as shown in FIG. 13. With the exemplary embodiment,
 an angle of eighty-five degrees has been found sufficient for the purposes
 of the present invention. Those skilled in the art will recognize that the
 center of gravity of the latch lever 52 is vertical of and radially inward
 of the pivot pin 54. Thus, in the stationary position shown in FIG. 13,
 the latch lever 52 is urged to rotate clockwise about the pin 54 to
 enforce engagement with the notch 82. However, when the work table 12 is
 rotating, centrifugal force will urge the latch lever 52 to rotate
 counter-clockwise about the pin 54 to release engagement from the notch
 82.
 The work table 12 is rotated by the motor 24 to position the station 14B at
 an unload station, the station 14C at a loading station and the station
 14D at a filling station.
 In the loading station, shown in FIG. 6, the power cylinder 86 raises the
 lifting rods 70 which raises the acid container 64 and the gasket 36
 allowing an unfilled battery case 68 to be inserted beneath the acid
 container 64. The power cylinder 86 then releases the lifting rods 70
 causing the battery case 68 to be secured in the cradle assembly 46. The
 power cylinder 86 is secured on a beam 88 which extends from a support 90
 secured to the base 30. The beam 88 also has a power cylinder 92 pivotally
 mounted thereon through a bracket 94. A rod portion 96 of the cylinder 92
 is pivotally connected with a lever 98 which is pivotally mounted on the
 base 30. After an empty battery case 68 is inserted and secured in the
 cradle at the loading station, the power cylinder 92 is actuated such that
 the lever 98 will contact the roller 78 thereby causing the lever 72 to
 rotate the cradle assembly 46 to the tilted position shown in FIG. 13 with
 the acid container radially inward of the battery case. The work table 12
 is indexed to position the tilted cradle assembly to the filling station.
 The apparatus used in the unloading station, to position the batteries, is
 substantially the same as the apparatus used in the loading station except
 that the unloading station does not need a tilting apparatus. In the
 unloading station, a power cylinder 86 raises the lifting rods 70 which
 raises the acid container 64 and the gasket 36 thereby releasing the
 clamping pressure from the battery case 68. The battery case 68 is then
 ejected from the cradle assembly 46. The power cylinder 86 then lowers the
 lifting rods 70 thereby lowering the acid container 64 to a rest position.
 The work table 12 is then indexed to position the emptied station 14 to
 the loading station.
 The filling station, shown in FIG. 7, has a stanchion 100 on which a power
 cylinder 102 and a lever 104 are mounted. The power cylinder 102 is
 mounted on a bracket 106 and has a rod 108 aligned to contact one arm 110
 of the lever 104. The lever 104 has another arm 112, substantially
 perpendicular to the arm 110, that is pivotally mounted on the stanchion
 100. A roller 114 is rotatably mounted on the arm 112. When the power
 cylinder 102 is actuated, the arm 104 is pivoted such that the roller 114
 will contact the cradle assembly 46. Through this action the cradle
 assembly 46 and the battery case 68 are rotated in the trunnions 38 to the
 horizontal position shown. When this attitude is achieved, a power
 cylinder 116 will lower a filling assembly 118 into position to fill the
 acid container 64 with acid.
 The filling assembly 118 has a bracket 119 which is slidably mounted on
 rods 122 for vertical movement under the influence of the power cylinder
 116. A valve assembly 124 is secured to the bracket 119 through leveling
 compensators 126. The valve assembly 124 has inlet tube connection 128
 that are connected by tubing, not shown, to an acid supply, not shown. The
 valve assembly 124 has outlet tubes 130 which are aligned with and
 inserted into fill passages 132 formed in the acid container 64. The fill
 passages 132 are in fluid communication with respective holding chambers
 134. A vent tube 136 is also provided at the valve assembly 124 which tube
 136 is inserted into a vent passage 138 formed in the container 64. The
 vent passage 138 communicates with each of the chambers 134 to permit air
 to escape therefrom when the acid is flowing into the chambers 134. The
 valve assembly 124 cam is a conventional two position valve which is
 opened to permit flow and closed to stop flow.
 Each chamber 134 has a top baffle 140, a bottom baffle 142 and an outlet
 passage 144 beneath the baffle 142. The outlet passages 144 communicate
 with respective battery fill openings 146. When the acid container is
 being filled, the left end 148 thereof is the upper surface and the
 chambers 134 are filled to a level substantially equal to the position of
 the lip 150 of the outlet passage 144. After the container 64 is filled,
 the cradle assembly is returned to the tilted position by deactuating the
 power cylinder 102 to pivot the lever 104 thereby lowering the roller 114.
 The work table 12 can then be indexed to perform respective unloading,
 loading and filling operations as required.
 When all of the openings 14 are occupied by empty battery cases 68 and
 their respective acid containers 64 are filled, the motor 24 is rotated at
 approximately 300 rpm. This will induce the acid to flow from the acid
 container to the battery case under the influence of centrifugal force. As
 the acid flows into the battery case, the battery case will increase in
 mass to cause all of the cradle assemblies 46 to pivot from the tilted
 position of cradle assembly 46A, shown in FIG. 2, toward a more horizontal
 position. The latch lever 52 is an inverted "L" shape. This places more
 mass above the pin 54 than below the pin 54. Due to the centrifugal forces
 on the latch lever 52, it is pivoted counter-clockwise about the pin 54 as
 viewed in FIG. 13 to release from the notch portion 82.
 As the rotational speed of the work table 12 increases, the acid in the
 chambers 134 will be forced by centrifugal action to flow over the baffle
 142 into the outlet passage 144 and therefore into the fill opening 146
 thereby filling the battery cells, not shown, with acid. The rotating of
 the plate continues for a predetermined time permitting all of the battery
 cells to be filled.
 The motor 24 is then slowed to a stop with one of the openings 14 being
 positioned in the unloading station. When the work table 12 is
 decelerating, the latch lever 52 remains pivoted due to the centrifugal
 forces. However, the assembly 36 will return to the horizontal position
 shown at 36A shown in FIGS. 1 and 2 because the battery case is now
 heavier and requires more rotary speed to remain tilted past the
 eighty-five degree angle at which the latch lever 52 is effective in the
 notch 82. When the motor stops or shortly before stopping, the latch lever
 52 will return to the position shown in FIG. 3. However, the cam wheel 74
 will have been returned to the position shown in FIG. 3 before the latch
 lever 52 is returned.
 The process cycle can begin again. That is a filled battery is unloaded at
 the unloading station, the work table 12 is indexed, a second filled
 battery is removed at the unloading station while a first empty battery
 case 68 is loaded simultaneously at the loading station, the work table 12
 is indexed, a third filled battery is removed at the unloading station, a
 second empty battery case 68 is loaded simultaneously at the loading
 station, and the acid container of the first empty acid container 64 is
 simultaneously filled with acid at the filling station. The indexing,
 unloading, loading of empty battery cases and filling of the acid
 container continues until all of the openings contain an empty battery
 case and a filled acid container. The spinning step is then performed and
 the cycle is repeated. As pointed out above, the latch lever 52 is
 automatically released from the notch 82 during the spinning step thereby
 eliminating a man or machine to perform the function when the unloading
 step is performed.