US3918607A

US3918607A - Chemical dispensing system

Info

Publication number: US3918607A
Application number: US444826A
Authority: US
Inventors: John J Rowlette
Original assignee: Individual
Current assignee: Individual
Priority date: 1974-02-22
Filing date: 1974-02-22
Publication date: 1975-11-11
Anticipated expiration: 1992-11-11

Abstract

Vertical stacks of tablets are stored in a cartridge that removably fits into a swimming pool dispenser housing. A battery is disposed in the cartridge, a motor for driving a tablet dispensing foot is disposed in the housing, and an electrical connection between the battery and the motor is established when the cartridge is inserted in the housing. The electrical connection is formed by coaxial conductors around which the foot rotates to engage the bottom tablet of each stack in turn, sliding it out from the rest of the stack and allowing it to drop from the dispenser into the pool. The electrical connection from the battery to the motor and the engagement of the foot are automatically severed and established without component damage when the cartridge is removed and inserted, respectively. A universal bracket permits the housing to be mounted on the pool edge whether it is a horizontal surface, or a bull nose coping tile, while maintaining the housing vertical so the force of gravity can be most effectively used to deliver the tablets to the water surface.

Description

United States Patent [191 Rowlette [451 Nov. 11, 1975 CHEMICAL DISPENSING SYSTEM John J. Rowlette, Arcadia, Calif.

[73] Assignee: Duane D. Erway, Rochester, NY.

a part interest [22] Filed: Feb. 22, 1974 [21] Appl. N0.: 444,826

[75] Inventor:

Primary E.\'aminerStanley 1-1. Tollberg Attorney; Agent, or FirmChristie, Parker & Hale [57] ABSTRACT Vertical stacks of tablets are stored in a cartridge that removably fits into a swimming pool dispenser housing. A battery is disposed in the cartridge, a motor for driving a tablet dispensing foot is disposed in the housing, and an electrical connection between the battery and the motor is established when the cartridge is inserted in the housing. The electrical connection is formed by coaxial conductors around which the foot rotates to engage the bottom tablet of each stack in turn, sliding it out from the rest of the stack and allowing it to drop from the dispenser into the pool. The electrical connection from the battery to the motor and the engagement of the foot are automatically severed and established without component damage when the cartridge is removed and inserted, respectively. A universal bracket permits the housing to be mounted on the pool edge whether it is a horizontal surface, or a bull nose coping tile, while maintaining the housing vertical so the force of gravity can be most effectively used to deliver the tablets to the water surface.

30 Claims, 9 Drawing Figures US. Patent Nov. 11, 1975 Sheet 1 of3 3,918,607

U.S. Patent Nov. 11, 1975 Sheet 2 013 U.S. Patent Nov. 11 1975 Sheet 3 013 3,918,607

. a $15 a CHEMICAL DISPENSING SYSTEM 7 I BACKGROUND or THE INVENTION" This invention relates to a chemical dispensing system and, more particularly,- tosuch asystem that is well suited to dispense a water evaporation retardant in tablet form at relatively constant intervals over a long time period upon the water surface of swimming pools, ponds, reservoirs or other bodies of water.

My US. Pat. No. 3,531,239, which issued Sept. 29,

. 1970, discloses a water evaporation retardant that can be applied to a watersurface in tablet form, as well as other solid forms. A large percentage of heat loss from the water in a swimming'pool is caused by evaporation. Therefore, the use of a water evaporation retardant can greatly decrease the cost of heating the pool and even increase the water temperature in the absence of heating It has been found that the evaoporation retardant SUMMARY OF THE INVENTION According. to the invention, a chemical dispensing system has a cartridge for storing tablets of a chemical, particularly a water evaoporation retardant, in parallel passages and a dispenser housing into which the cartridge removably fits. The housing contains a tablet dispensing assembly that engages the cartridge and an electrical clock motor that drives the dispensing assembly to sequentially deliver tablets from the cartridge to the water at relatively constant intervals over a long period of time, I

A feature of the invention is the provision of a battery in the cartridge, and an electrical connection from the battery to the motor to provide power thereto. When a cartridge is removed from and inserted into the dispenser housing, the electrical connection is severed and established, respectively, without damaging any of the components ofthe system. Preferably, the electrical connection comprises coaxial conductors aligned with acentral axis along which the battery and motor lie.

Another feature of the invention is the storage of the tablets in parallel vertical stacks arrangedin a circle about-thecentral axis of the system inside a cartridge that removably fits into the dispenser housing from Responsive to the motor, the tablet at the. bottom of each stack is freed in sequence to fall through the passageway to the exit. I I a I Another feature of the invention is the provision of a tablet dispensing foot that rides along the stacks of tablets at the level of the bottom tablet in each.stack.. The stacks are held up by tablet retaining protrusions, such that the bottom tablet in each stack lies completely below the main body of the cartridge, and the second tablet from the bottom in each stack lies partially in its tablet storage passage. Preferably, the foot partially overlies one of the protrusions, and is connected by a slim post, which extends between the protrusions, to a driving shaft; the driving shaft'fits around the coaxial conductors, and is coupled by a great train to the motor. The post is vertically movable and is urged by a spring in an upward direction toward the cartridge. As a result, the foot is temporarily depressed below the level of the bottom tablet in the stacks when the cartridge is oriented so the protrusions lie above the foot during cartridge insertion. The foot is attached to the slim post by a hinge that permits the foot to rotate and slide out between the protrusions as the cartrdige is removed, should the foot have traveled to a position under a stack.

Another feature of the invention is a universal bracke't assembly that permits the dispenser housing to be mounted in a vertical position at the edge of a swimming pool whether it be a horizontal surface or a bull nose coping tile. A lower angular member is fixedly attached to the edge of the pool. The dispenser housing is pivotably attached to an upper annular member. The

upper member is adjustably attached to i the lower member such that the dispenser housing pivots to a vertical position in abutment with the vertical side of the lower angular member.

In the preferred embodiment, the cartridge has a cylindrical body portion aligned with the central axis of the system when in position in the housing. The body portion has a plurality of parallel passages arranged in a circle about the central axis, in which the stacks of tablets are stored, and a center passage on the central axis in which the battery is located. At the bottom of the cartridge, an inner ring and an outer ring define an annular channel in which the tablet dispensing foot moves under the tablet storage passages at the level of the bottom tablet in each stack. The tablet retaining protrusions are formed at intervals along the rings aligned with the stacks of tablets.

BRIEF DESCRIPTION OF THE DRAWINGS The features of a specific embodiment of the best mode contemplated of carrying out the invention are illustrated in the drawings, in which:

FIG. 1 is a side sectional view of a swimming pool chemical dispensing system incorporating the principles of the'invention;

FIG. 2 is a sectional view of the swimming pool chemical dispensing system taken along line 22 in FIG. 1;

FIG. 3 is a sectional view of the system taken along line 33 in FIG. 1;

FIG. 4 is a side sectional view of the center post assembly of the system;

FIG. 5 is a side, partially sectional view of the tablet dispensing assembly of the system;

FIG. 5A is a front view of part of the dispensing assembly taken along line 5A-5A in FIG. 5;

FIG. 5B is a side view of part of the dispensing assembly when the dispensing foot is rotated out of operating position;

FIG. 6 is an exploded side elevation view of the mounting bracket for the swimming pool chemical dispensing system; and

FIG. 7 is a top plan view of the mounting bracket of FIG; 6.

DETAILED DESCRIPTION OF THE SPECIFIC EMBODIMENT In FIG. 1 there is shown a swimming pool chemical dispensing system comprising a permanent dispenser housing 10, an expendable chemical storage cartridge 11 that removably fits into housing 10, and a permanent lid 12. As disclosed in more detail below in connection with FIGS. 6 and 7, the system is supported above the water surface of the swimming pool with approximate alignment of its vertical axis 13.

A cylindrical body 14 of cartridge 11 has a center passage aligned with axis 13 and a plurality, e.g., eight, of passages 16 arranged in a circle around passage 15. Passage 15 and passages 16 are parallel to each other and vertical. A swimming pool chemical in the form of tablets is stored in passages 16 in stacks 20. It is convenient to mold body 14 from styrofoam. If the body 14 is fabricated by molding, it is advantageous for good mold release to form passages 16 with a draft; but it is also desirable to maintain a relatively close fit between the tablets and passages 16 to prevent lateral movement of the tablets during storage and transportation. To satisfy both these considerations, as illustrated in FIG. 1, the diameter of passages 16 tapers down from top to bottom, and three or more ribs 17 are formed along the length of passage 16. Ribs 17 also taper down from the top of passages 16, where their protrusion into passage 16 is large, to the bottom thereof, where their protrusion is small, so that the effective diameter of passages 16 is the same throughout their length. In other words, ribs 17 equalize the effective diameters of passages 16. The provision of ribs 17 does not hinder the release of body 14 from its mold in the course of fabrication. The system is specifically designed to dispense an evaporation retardant such as that disclosed in my U.S. Pat. No. 3,531,239, which issued September 29, 1970. A conventional dry cell flashlight battery 21, e.g., a D cell, lies in the bottom portion of passage 15 with a positive terminal 22 facing downward. A contact 23, which is made of an electrically conductive spring metal, such as brass, extends from a negative terminal 24 of battery 21 to the bottom of cartridge 11 in the vicinity of positive terminal 22. An inner tablet dispensing ring 25 and an outer tablet dispensing ring 26 are cemented to the bottom of body 14. Rings 25 and 26 form between them an annular channel 30, slightly wider than the tablets, in which a rotating tablet dispensing foot 68 rides (FIG. 2). Inner ring 25 has an outward tablet retaining protrusion 27 at the bottom edge of channel 30 directly under each of passages 16. Outer ring 26 has an inward tablet retaining protrusion 28 at the bottom edge of channel 30 directly under each of passages 16. Each of protrusions 27 present a smooth upper surface over which dispensing foot 68 traverses. The bottom tablet in each of stacks rests on the corresponding

protrusions

27 and 28. Thus, between stacks 20 the tablets are free to fall out of channel 30, but directly under stacks 20 the tablets are held up by

protrusions

27 and 28. A nipple 34 (FIG. 2) is formed at the leading edge to the movement of dispensing foot 68 on the top surface of each of protrusions 28 to prevent inadvertant reverse movement of the bottom tablet of each of stacks 20, i.e., movement in the direction opposite to movement of dispensing foot 68. As illustrated in FIG. 1, the thickness of rings and 26 is selected so the bottom tablet in each of stacks 20 lies completely below body 14 within channel 30, and about one-half of the second tablet from the bottom in each of the stacks 20 lies below body 14 in channel 30, the other half lying above channel 30 in the corresponding passage 16. In other words,

protrusions

27 and 28 are spaced from the end of body 14 a distance greater than one tablet thickness and less than two tablet thicknesses. The outer periphery of ring 26 has a plurality, e.g., four, of keyways 35. As illustrated in FIG. 1, the tablets of stacks 20 have a close fit in passages 16, so the tablets remain axially aligned with pas.- sages 16 as they move. Likewise,

protrusions

27 and 28 hold the bottom tablet of stacks 20 so they are aligned with passages 16.

A truncated hollow conical body 36 of dispenser housing 10 has a plurality, e.g., eight, of strengthening

ribs

37 and 38. A pair of vertical spaced protrusions 33 are formed outside body 36 for purposes of mounting. Orienting side surfaces 32 on protrusions 33 are paral? lel to axis 13. Underneath ribs 37 are a plurality, e.g., four, of protrusions 18 (FIG. 2). A spacer ring 39 has a plurality, e.g., four, of indexing protrusions 40, and a plurality, e.g., four, of recesses 19 (FIG. 2) for clasping protrusions 18. Ring 39 is secured to the bottom of ribs 37 by cement. When cartridge 11 fits in the hollowed cavity of body 36, as shown in FIG. 1, protrusions 40 engage keyways 35 to fix the angular position of cartridge 11 about axis 13. The bottom of ring 39 has a plurality, e.g., four, of mounting columns 41 connected by a thin annular support web 42. FIG. 2 illustrates the proper relative position of columns 41 and recesses 19 about axis 13. In FIG. 1, columns 41 are shown in alignment with recesses 19 to permit both to be represented in a single section view. A truncated conical tablet deflecting shield 43 has a plurality, e.g., four, of mounting extensions 44 (FIG. 3). Fasteners 45 attach mounting extensions 44 to mounting columns 41, thereby securing shield 43 to spacer ring 39. In the annular region under channel 30 of cartridge 11, shield 43 presents a downwardly and outwardly sloping deflecting surface. An electric clock motor is secured by a convertti'onal fastener not shown to a mounting plate 51, which is attached to the bottom of shield 43 by fasteners 52. Clock motor 50 has an output, i.e., hour, shaft 53, that extends upwardly through an opening in plate 51. A spur gear 54 is mounted at the end of shaft 53 above plate 51. Shaft 53 rotates one revolution in twelve hours. A center post assembly 55, which is described in more detail below in connection with FIG. 4, extends along axis 13 from plate 51 to battery 21. The bottom of post assembly 55 fits in a bore 56 of plate 51, where it is secured by cement. Post assembly 55 serves two functions. The first function is to transmit electrical power from battery 21 to plate 51, where insulated conductors 57a and 57b, which extend through a passage 58 from bore 56 to the periphery of plate 51, transmit the electrical power to clock motor 50. The second function is to support a rotating tablet dispensing assembly 59, which is described in detail below in connection with FIG. 5. Assembly 59 has a bore 60 aligned with axis 13. Post assembly 55 fits loosely enough in bore 60 so assembly 59 is free to rotate around post 55 but not so loose as to introduce appreciable wobble. Around the bottom of assembly 59 is formed a spur gear 61 having teeth that mesh with the teeth of spur gear 54. By way of example, the gear ratio could be 1:1. Thus, each time that shaft 53 makes one complete revolution, assembly 59 also makes one revolution.

As described in more detail below in connection with FIG. 5, assembly 59 carries tablet dispensing foot 68. As assembly 59 rotates. foot 68 traverses channel 30 and pushes the bottom tablet in each of stacks 20 in turn along channel 30 until such tablet is clear of the corresponding

protrusions

27 and 28, where it is free to fall. While the bottom tablet in one of stacks 20 is being pushed along channel 30, the second tablet from the bottom is held in place by the walls of the corresponding passage 16. After the bottom tablet is clear of

protrusions

27 and 28 and is thereby dispensed, the second tablet from the bottom slides down against protrusions 27 sand 28 to replace It. In this manner, the tablets stored in cartridge 11 are sequentially dispensed one by one as assembly 59 rotates and foot 68 traverses a given path. which is circular. The dispensed tablets fall by vir tue of gravity until they hit shield 43 and are deflected outwardly to avoid clock motor 50.

On the bottom of body 36 are mounted an inner funncl 69 and an outer funnel 70. Funnel 70 is secured to the bottom of body 36 by fasteners 71, and funnel 69 is clamped between funnel 70 and the bottom of body 36. Funnel 69 has a hole 72 drilled along an axis parallel to and spaced from axis 13, and funnel 70 has a hole 73 drilled along an axis coinciding with axis 13.

Holes

72 and 73, which serve as the exit from the dispensing system. are large enough to permit the tablets to pass without difficulty. After the dispensed tablets are deflected outwardly by shield 43, they fall freely through the annular region around clock motor 50 until they are deflected by the inwardly and downwardly sloping surface of funnel 69. At the bottom of funnel 69, the tablets fall through hole 72, fall through hole 73, and drop into the water below dispenser housing 10.

Holes

72 and 73 are intentionally misaligned to minimize the upward flow of water vapor into the interior of body 36. A plurality of small holes 74 are drilled through funnel 70 to permit trapped water vapor to escane from the region between

funnels

69 and 70. If too much water vapor enters the interior of body 36 despite these measures. so the tablets become moist enough to impair their dispensability. more elaborate measures can be taken. For example. silica gel could be placed in the free space of passage lying above battery 24; or a combination of chemicals that give off ammonia when exposed to water vapor could be placed inside body 36 below cartridge 11, so the lighter ammonia occupies the interior of body 36 where it is effectively trapped and thus prevents the upward movement of the water vapor through

holes

72 and 73.

Reference is made to FIG. 4 for a detailed description of post assembly 55. The bottom ofa hollow electrically conductive tube 80 fits in bore 56, where it is secured to plate 5| by cement. By way of example, tube 80 could be rendered electrically conductive by nickelplating its outer surface. or it could be made from a conductive material and optionally nickel-plated to reduce corrosion. A spring retaining ring 8] is secured inside tube 80 by cement. An electrically insulative disc 82 is attached to an electrically conductive disc 83 by cement. By way of example, disc 83 could be pure nickel. An insulated. flexible electrical conductor 84 extends through the Interior of tube 80. At one end, conductor 84 is electrically connected to the side oldlsc 83 facing disc 82. At the other end, conductor 84 is electrically connected to conductor 57a. The outer surface of tube 80 is electrically connected to conductor 57b. A compression. spring 85 extends between retaining ring 81 and disc 82. Battery 21, positive terminal 22. and contact 23 of cartridge 11 are shown in their positions relative to post assembly 55, as cartridge II is about to be placed in dispenser housing 10. As cartridge 11, which is not shown in FIG. 4, moves downwardly, terminal 22 contacts disc 83 and contact 23 engages the outside surface oftube 80. As depicted by the arrows. battery 21 moves downward, disc 83 moves downward, and contact 23 moves outward until cartridge ll bottoms against ring 39 (FIG. 1). At such time. discs 82 and 83 are spaced from the end of tube 80, thereby providng leeway for variations in the position of battery 21. The force of spring 85 insures that good electrical contact is maintained from positive terminal 22 through disc 83 and conductor 84 to conductor 57a. By virtue of its flexibility. the excess length of conductor 84 coils within tube 80. The outward deformation of contact 23 which is caused by its engagement with the outer surface of tube 80, insures that good electrical contact is maintained from negative terminal 24 through tube 80 to conductor 57b. To improve the corrosion resistance of the electrical connection, the end ofcontact 23 engaging the outer surface of tube 80 could be plated with nickel.

Reference is made to FIGS. 3, 5, 5A, and 5B for a detailed description of tablet dispensing assembly 59. Bore 60 is formed in a central shaft portion 86. At the upper end of shaft portion 86, a crank portion 87 extends radially outward. A post 88 fits slidably in a bore 89 at the end of crank portion 87. The diameter of post 88 is smaller than the space between

protrusions

27 and 28. A button 90 is formed on the lower end of post 88 as a stop to prevent it from sliding upwardly out of bore 89. A leaf spring 91, which is secured to crank portion 87 by a rivet 92, engages a slot in button 90 and urges post 88 in an upward direction. Also. rotation of post 88 is prevented by this engagement. Tablet dispensing foot 68 is attached to the upper end of post 88 by a hinge 93 (FIG. 5A). Foot 68 is free to rotate about hinge 93 in a clockwise direction. from its position as viewed in FIG. 5. A lower surface 94 of foot 68 is shaped to limit the extent of rotation of foot 68. In FIG. 5 foot 68 is represented at the counterclockwise limit of its rotational path. In FIG. 58, foot 68 is represented at the clockwise limit of its rotational path. Thus. surface 94 and the adjacent surface of post 88 function as a cam and a cam follower to limitthe rotation of foot 68. The center of gravity of foot 68 lies to the left of hinge 9 3, as view in FIG. 5, so gravity urges foot 68 in a counterclockwise direction to the position depicted in FIG. 5.

If dispenser assembly 59 happens to be oriented so foot 68 lies between adjacent stacks 20 when cartridge 11 is inserted into dispenser housing 10, foot 68 immediately moves up into channel 30 at the level of the bottom tablets. as shown in FIG. I. In this position, button 90 abuts the bottom of crank portion 87 and the top of foot 68 lies below the second tablet from the bottom of the stack. However, if dispenser assembly 59 happens to be oriented so foot 68 lies under one of stacks 20 when cartridge 11 is inserted into dispenser housing 10,

protrusions

27 and 28 prevent foot 68 from moving upward to the level of the bottom tablets. In such cases, cartridge ll depresses foot 68 downwardly to push post 88 in opposition to the force of spring 91, where is remains until assembly 59 rotates sufficiently for foot 68 to be clear of

protrusions

27 and 28; then the force of spring 91 urges post 88 upwardly until button 90 abuts 7 the bottom of crank portion 87 and foot 68 assumes a position at the level of-the bottom tablets.

if dispenser assembly 59 happens to be oriented so foot 68 lies between adjacent stacks 20 when cartridge 11 is removed from dispenser housing 10, foot 68 is disengaged from channel 30 without touching cartridge 11. However, if dispenser assembly 59 happens to be oriented so foot 68 liesunder one of stacks 20 when cartridge 11 is removed, foot 68 contacts protrusion 27 as cartridge 11 is removed. Since foot 68 is free to rotate in a clockwise direction, it slips out of the space between

protrusions

27 and 28 and is thereby disengaged from channel 30 without being damaged.

Since the force of gravity is used to deliver the tablets from cartridge 11 to the water, it is important that dispenser housing be oriented so..axis 13 is approximately vertical. A universal bracket assembly illustrated in F168. 6 and 7 permits dispenser housing 10 to be mounted vertically at pool edges whether the mounting surface is flat or is any of the variety of bull nose copings with different shapes. A lower angular member 100 is secured by cement and by two fasteners 101 to a flexible strip 102, which is, in turn, secured by cement to the edge of the swimming pool represented at 103. Fasteners 101 each have a head recessed in strip 102 and are fixed against rotation. For example. member 100 can be made of stainless steel, and a cloth re-inforced neoprene rubber strip could be used for member 102 to provide the desired flex without stretching so much that bracket 100 would tip forward under the weight of dispenser housing 10. A portion 100a abuts the upright side of the pool and a portion 10% lies above the coping. An upper angular member 104 has a portion 104 a that abuts portion 100b, and is fastened to it by two finger nuts 105, which screw onto fasteners 10]. Member 104 also has a portion 104b from which vertical hinge mounting plate portions [040 extend. Portion 104a has slots 106 that permit the position of member 104 to be adjusted toward or away from the pool edge relative to .nember 100. Hinge mounting plate portions 1040 are spaced apart just enough to fit between hinge mounting protrusions 33 of body 36. Plate portions 104a and protrusions 33 are joined by fasteners 107, which serve as hinge points, allowing dispenser housing 10 to rotate. Thus dispenser housing 10 rotates in a clockwise direction, as viewed in FIG. 6. until protrusions 33 abut portion 100a. Member 104 is adjusted relative to member 100 until orient ing side surfaces 32 are flush with portion 1000. When this adjustment is made. axis 13 ofdispenser housing 10 is vertical, assuming that portion 100a of member 100 is exactly vertical. if this is not the case, then member 104 is adjusted accordingly relative to member 100, so dispenser housing 10 is vertically oriented. Dispenser housing 10 is free to rotate in either direction. as viewed in H0. 6, in order to accomplish this adjustment.

The described swimming pool chemical dispensing system is designed to accommodate expendable tablet storage cartridges, i.e., cartridge 11. Thus, for example, one cartridge could carry a one month supply of tablets and a battery having sufficient electrical energy storage capacity to energize the dispenser actuating motor, i.e., clock motor 50, for a comparable period of time. Each month, the lid is taken off; the used cartridge is removed upwardly from the dispenser housing, thrown away, and replaced from above with a new cartridge;

and the lid is put back on. As the new cartridge is placed in the dispenser housing, the electrical connection between the battery in the cartridge and the motor in the dispenser housing is automatically established in the manner described above in connection with FIG. 4.

' tom tablet of each stack in the new cartridge, i.e., positioned inchannel 30, in the manner described above in connection with FIG. 5. Thereafter, the motor drives the actuating mechanism in response to the energy from the battery so the tablets are dispensed sequentiallyone at a time over the period of a month. When the cartridge is removed at the end of the month, the electrical connection from the battery to the motor is automatically interrupted and the tablet actuating mechanism is disengaged from the cartridge without damage to the components of dispenser housing 10.

The described embodiment of the invention is only considered to be preferred and illustrative of the inventive concept; the scope of the invention is not to be restricted to such embodiment. Various and numerous other arrangements may be devised by one skilled in the art without departing from the spirit and scope of this invention. For example, it may be desirable to automatically disconnect clock 50 during certain times. it has been found that during periods of time in which the pool is not being used, such as at night, less frequent applications of water retardant are required to maintain an effective retarding layer on the water surface. Therefore, it would usually be desirable to disconnect clock 50 at night. This could be done by means of a photocell actuated electrical circuit that switches off clock 50 when the sun goes down, and switches on clock 50 when the sun comes up. Alternatively, this could be done by a gear train between assembly 59 and shaft 53 which disengages during part of each day, e.g.. every other complete revolution of shaft 53. Furthermore, the stacks of tablets in the cartridge could be arranged differently, e.g., in rows, in which case the given path that the tablet dispensing foot traverses would not be circular. While mounting the battery in the cartridge is most convenient for the user, it would also be possible to design the dispenser with the battery in the dispenser, rather than in the cartridge. Further, the tablets could take many sizes and shapes, including what are sometimes regarded as briquettes or pellets, or in general solid compact units.

What is claimed is: l. A swimming pool chemical dispensing system comprising:

a cartridge for storing tablets of a swimming pool chemical; a dispenser housing into which the cartridge removably fits; means for attaching the housing to the edge of a swimming pool; a battery having a positive terminal and a negative terminal disposed in the cartridge;

means disposed in the housing including an electrical clock motor for dispensing tablets stored in the cartridge into the swimming pool responsive to the power source; and means operable when the cartridge is positioned in the housing for transmitting power from the source to the dispensing means to dispense tablets stored in the cartridge, the power transmitting means comprising an electrically conductive spring contact extending from one terminal of the battery penser'housing, the tube extending from the cartridge to the clock motor' such that the spring contact engages the tube in deformation, an electrical conductor extending through the'tube from v the cartridge to the clock motor, an electrically conductivedisc contact at the end of the tube adjacent to the cartridge positioned to engage the other terminal of thebattery, spring means urging the disc contact into engagement with the other contact of the battery, and means for connecting the conductor and the tube to the clock motor. 2. The system of claim 1, in which the cartridge has a'plurality of parallel vertical passages above the tube in which the tablets are stored in stacks, the passages being arranged in a circle having a center aligned with the tube; v

the clock motor has an output shaft below the cartridge in spaced parallel relationship to the tube; and

the tablet dispensing means comprises a driving shaft with a bore that fits around the tube so the driving shaft is rotatable thereabout, means for coupling the driving shaft to the output shaft of the clock motor, a crank extending from the driving shaft outwardly to end at the circle of passages, and a tablet dispensing foot mounted at the end of the crank below the cartridge to rotate along the circle of passages responsive to the clock motor, the foot removing the tablet at the bottom of each stack in turn as the foot rotates along the circle of passages.

3. A swimming pool chemical dispensing system comprising:

a cartridge having a body portion through which a plurality of parallel vertical passages are formed, the passages having bottom ends arrangedto lie along a given path, the cartridge including integral tablet retaining means in alignment with the bottom end of each passage for holding upthe corresponding stack such that the bottom tablet inthe corresponding stack lies completely below the body portion outside the passage, and the second tablet from the bottom in the corresponding stack lies at least partially within the passage;

a stack of swimming pool chemical tablets stored in each passage, each tablet being free tomove downward to replace the tablet below when such tablet moves downward;

a dispenser housing'into which the cartridge removably fits from above;

tablet dispensing member within the dispenser housing, the member being normally disposed at the level of the bottom tablet in the stacks when the cartridge is positioned in the dispenser housing, being downwardly depressible to a point under the bottom tablet in the stacks when the member lies under one of the stacks during insertion of the cartridge into the housing, and being returnable to the level of the bottom tablet in the stacks aftermovement of the member out from under said one stack;

and means within the dispenser housing for repeatedly moving the dispensing member along the given path to slide the bottom tablet of each stack in succession out of such stack for dispensing in a swimming pool.

v 10 4. The system of claim 3, in which the tablet retaining means for each passage comprises a first protrusion and a second protrusion extending toward each other in a direction transverse to the given path, the protrusions being spaced downwardly from the body portion of the cartridge a distance greater than the thickness of one tablet and less than the thickness of two tablets, and the foot moving means includes a post extending upwardly between the protrusions and means for attaching the foot to the top of the post.

a 5. The system of claim 4, in which the foot extends transverse to the given path over one of the protrusions and the attaching means is a hinge connection between the foot and the post adapted to permit the foot to slide between the protrusions when the cartridge is removed, the hinge connection being offset from the center of gravity of the foot so gravity tends to return the foot to a transverse position over one of the protrusions.

6. The system of claim 5, in which the moving means additionally comprises a post support member below the cartridge having a bore in which the post slidably fits and spring means for urging the post in an upward direction.

7. The system of claim 6, in which the lower end of the post has a button that prevents the post from sliding through the bore.

8. The system of claim 7, in which the passages of the cartridge are arranged in a circle around a central axis, the post support member rotates about the central axis, and the given path is circular.

9. The system of claim 8, in which the cartridge has a bottom portion comprising an inner ring disposed inside the circle of passages, the outer perimeter of the inner ring defining one wall of an annular channel in which the foot rides, and an outer ring disposed outside the circle of passages, the inner perimeter of the outer ring defining the other wall of the annular channel.

10. The system of claim 9, in which the protrusions are formed on the outer and inner rings, respectively.

11. A cartridge for a swimming pool chemical dispensing system having a dispenser housing with a cavity into which the cartridge removably fits and a dispensing assembly with a foot that moves through the cavity in a given path, the cartridge comprising:

a body portion through which a plurality of parallel vertical passages are formed, the passages having bottom ends arranged to lie along the given path;

a stack of swimming pool chemical tablets stored in each passage, each tablet being free to move downward to replace the tablet below when such tablet moves downward, the tablets having a sufficiently close fit in their respective passages to axially align the tablets with their respective passages during movement; 7 bottom portion in which a channel is formed, the channel being slightly wider than the tablets and extending between the bottom ends of the passages along the given path so the foot of the dispensing assembly can ride in the channels; and tablet retaining means in alignment with the bottom end of each passage for holding up the corresponding stack such that the bottom tablet in the stack lies completely below the body portion outside the passage and the second tablet from the bottom in the stack lies at least partially within the passage,

the bottom tablet in the stacks being free to drop away from the cartridge when pushed between suc- 1 1 cessive retaining means by the foot of the dispensing assembly.

12. The cartridge of claim 11, in which the tablet retaining means holds up the bottom tablet in each stack in axial alignment with the corresponding passage.

13. The cartridge of claim 12, in which the passages through the body are arranged so their bottom ends lie in a circle.

14. The cartridge of claim 11, in which the bottom portion comprises an inner ring disposed inside the circle of passages, the outer perimeter of the inner ring defining one wall of the channel, and an outer ring disposed outside the circle of passages, the inner perimeter of the outer ring defining the other wall of the channel.

15. The cartridge of claim 14, in which the tablet retaining means each comprise an inward protrusion from the outer ring and an outward protrusion from the inner ring, the inner and outer protrusions being spaced from the body portions a distance greater than the thickness of one tablet and less than the thickness of two tablets.

16. The cartridge of claim 15, in which the leading edge of one of the protrusions of each tablet retaining means has a tablet retaining nipple extending upwardly toward the body portion, and the other protrusion of each tablet retaining means presents a smooth upper surface for movement of the dispensing foot thereacross.

17. The cartridge of claim 16, in which the body portion has a vertical central passage lying inside the circle of passages, and a battery for energizing the dispensing assembly disposed in the central passage.

18. A swimming pool water retardant dispensing system comprising:

a cartridge for storing tablets of the water retardant,

the cartridge having a plurality of passages disposed in parallel relationship about a central axis;

a stack of water retardant tablets disposed in each passage of the cartridge;

a dispenser housing into which the cartridge removably fits from above such that the central axis of the cartridge is vertically oriented, the housing having a vertical opening between the bottom of the cartridge and an exit designed to lie above the water surface of the swimming pool;

a motor disposed in the vertical opening of the dispenser housing underneath the cartridge in alignment with its central axis to define with the housing an annular passageway between the cartridge and the exit; and

means responsive to the motor for sequentially freeing the tablet at the bottom of each stack to fall through the passageway to the exit.

19. The system of claim 18, in which the motor has a generally cylindrical shape with a periphery that extends away from the central axis of the cartridge at least as far as the passages in the cartridge and the housing has a downwardly and outwardly slanted shield lying in the vertical passageway between the cartridge and motor so as to deflect tablets falling from the cartridge outwardly from the motor.

20. The system of claim 18, in which the dispenser housing has an inner funnel shaped bottom portion with a first opening larger that the tablets near its apex and an outer funnel shaped bottom portion with a second opening larger that the tablets near its apex, the

12 first and second openings of the funnels defining the exit.

21. The system of claim 20, in which the openings of the bottom portions have axes that are laterally offset relative to each other.

22. The system of claim 21, in which the axis of the second opening is aligned with the central axis of the cartridge and the axis of the first opening is laterally offset from the central axis of the cartridge.

23. The system of claim 22, in which a plurality of small holes for water vapor escape are formed in the outer bottom portion.

24. A swimming pool chemical dispensing system comprising:

a dispensing unit having a central axis along which tablets of a swimming pool chemical are adpated to fall to an exit point lying above the water surface of the swimming pool;

a bracket having a stopping surface and being adapted to be attached to the edge of the swimming pool;

means for pivotally mounting the dispenser unit to the bracket so that the dispensing unit is free to rotate until it abuts the stopping surface, the stopping surface being oriented so the central axis of the dis-. pensing unit is vertical when the dispensing unit abuts the stopping surface; and

means for securing the dispensing unit against rotation.

25. The system of claim 24, in which the bracket comprises a flexible strip fixed to the edge of the swimming pool, a lower angular member having a first vertical portion abutting the edge of the pool and a second horizontal portion abutting and fixed to the flexible strip, an upper angular member having a first horizontal portion abutting the second portion of the lower member and a second vertical portion extending upwardly from the first portion, and means for adjustably attaching the first portion of the upper member to the second portion of the lower member such that the second portion of the upper member can be extended toward and retracted from the pool edge; the dispenser unit has adjacent to the bracket a guiding surface parallel to the central axis; and the mounting means connects the dispenser unit to the second portion of the upper member so the dispenser unit is free to rotate until its guiding surface abuts the first portion of the bottom member.

26. A water evaporation retardant dispensing system comprising:

a cartridge having a body portion through which a plurality of parallel vertical passages are formed;

a stack of disc-shaped water evaporation retardant tablets stored in each passage, each tablet being free to move downward to replace the tablet below when such tablet moves downward;

a dispenser housing into which the cartridge removably fits;

means for attaching the housing to the edge of a swimming pool;

a motor in the housing having an output shaft that rotates at a slow relatively constant speed without interruption over predetermined periods of time; and

a tablet dispensing mechanism in the housing, the tablet dispensing mechanism sequentially removing tablets from the bottom of each stack in turn and dispensing such tablets into the pool responsive to the motor at a rate proportional to the speed of rotation of the output shaft.

27. A swimming pool chemical dispensing system comprising:

a cartridge having a body portion through which a plurality of parallel vertical passages are formed, the passages having bottom ends arranged to lie along a given path;

. a stack of swimming pool chemical tablets stored in each passage, each tablet being free to move downward to replace the tablet below when such tablet moves downward;

tablet retaining means in alignment with the bottom end of each passage for holding up the corresponding stack such that the bottom tablet in the corresponding stack lies completely below the body portion outside the passage, and the second tablet from the bottom in the corresponding stack lies at least partially within the passage;

a dispenser housing into which the cartridge removably fits from above;

a tablet dispensing foot within the dispenser housing, the foot being disposed at the level of the bottom tablet in the stacks when the cartridge is positioned in the dispenser housing;

means within the dispenser housing for repeatedly moving the dispensing foot along the given path to slide the bottom tablet of each stack in succession 14 out of such stack for dispensing in a swimming pool; and

means for disengaging the tablet dispensing foot from the tablet retaining means when the foot lies under one of the stacks during removal of the cartridge from the housing.

28. The system of claim 27, in which the tablet retaining means for each passage comprises a first protrusion and a second protrusion extending toward each other in a direction-transverse to the given path, the protrusions being spaced downwardly from the body portion of the cartridge a distance greater than the thickness of one tablet and less than the thickness of two tablets, the foot moving means includes a post extending upwardly between the protrusions, the foot extends transverse to the given path over one of the protrusions, and the foot disengaging means comprises a hinge connection between the foot and the post adaptedto pivot so the foot slides between the protrusions when the cartridge is removed.

29. The system of claim 27, in which the tablet dispensing foot is downwardly depressible when the foot lies under one of the stacks during insertion of the cartridge into the housing.

30. The system of claim 3, in which the tablet dispensing member'is spring loaded to return the member to the level of the bottom tablet after movement of the member out from under said one stack.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent NO. 5 7 Dated November 11, 1975 Inventor(s) John J. Rowlette Page 1 of 3 It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Columns 5 through 8 as shown on the attached pages should be included, but will apply to the grant only.

Signed and Scaled this tenth Day of February 1976 [SEAL] Arrest:

RUTH C. MASON C. MARSHALL DANN Allesting Ojficer Commissioner of Patents and Trademarks As described in more detail below in connection with HO. 5. assembly 59 carries tablet dispensing foot 68. As assembly 59 rotates. foot 68 traverses channel 30 and pushes the bottom tablet in each of stacks in turn along channel until such tablet is clear of the corresponding

protrusions

27 and 28. where it is free to fall. While the bottom tablet in one ofstacks 20 is being pushed along channel 30. the second tablet from the bottom is held in place by the walls of the correspond ing passage 16. After the bottom tablet is clear of

protrusions

27 and 28 and is thereby dispensed. the second tablet from the bottom slides down against protrusions 27 aand 28 to replace it. In this manner. the tablets stored in cartridge 11 are sequentially dispensed one by one as assembly 59 rotates and foot 68 traverses a given path, which is circular. The dispensed tablets fall by virtue of gravity until they hit shield 43 and are deflected outwardly to avoid clock motor 50.

On the bottom of body 36 are mounted an inner funnel 69 and an outer funnel 70. Funnel 70 is secured to the bottom of body 36 by fasteners 71, and funnel 69 is clamped between funnel 70 and the bottom of body 36. Funnel 69 has a hole 72 drilled along an axis parallel to and spaced from axis 13. and funnel 70 has a hole 73 drilled along an axis coinciding with axis 13.

Holes

72 and 73, which serve as the exit from the dispensing system, are large enough to permit the tablets to pass without difficulty. After the dispensed tablets are deflected outwardly by shield 43. they fall freely through the annular region around clock motor until they are deflected by the inwardly and downwardly sloping surface offunncl 69. At the bottom of funnel 69, the tablets fall through hole 72, fall through hole 73, and drop into the water below dispenser housing 10.

Holes

72 and 73 are intentionally misaligned to minimize the upward flow ofwater vapor into the interior of body 36. A plurality of small holes 74 are drilled through funnel to permit trapped water vapor to escape from the region between

funnels

69 and 70. lf too much water vapor enters the interior of body 36 despite these measures. so the tablets become moist enough to impair their dispensabihty. more elaborate measures can be taken. For example. silica gel could be placed in the free space of passage 15 lying above battery 24; or a combination of chemicals that give off ammonia when exposed to water vapor could be placed inside body 36 below cartridge 11. so the lighter ammonia occupies the interior of body 36 where it is effectively trapped and thus prevents the upward movement of the water vapor through

holes

72 and 73.

Reference is made to FIG. 4 for a detailed description of post assembly 55. The bottom of a hollow elec trically conductive tube fits in bore 56, where it is secured to plate 51 by cement. By way ofexample, tube 80 could be rendered electrically conductive by nickelplating its outer surface. or it could be made from a conductive material and optionally nickel-plated to reduce corrosion. A spring retaining ring 81 is secured inside tube 80 by cement. .-\n electrically insulativc disc 32 is attached to an electrically conductive disc 83 by cement. By way of example. disc 83 could be pure nickel. An insulat'cd flexible electrical conductor 84 extends through the interior of tube 80. At one end. conductor 84 is electrically connected to the side ofdisc 83 facing disc 32. At the other end. conductor 84 is electrically connected to conductor 57a The outer surface of tube 80 is electrically connected to conductor 57b. A compression spring 85 extends between retaining ring 8i and disc 82. Buttery 21. positive terminal 22. and contact 23 of cartridge II are shown in their positions relative to post assembly 55, as cartridge H is about to be placed in dispenser housing l0. As cartridge 11. which is not shown in H6. 4, moves downardly. terminal 22 contacts disc 83 and contact 23 engages the outside surface of tube 80. As depicted by the arrows. battery 21 moves downward. disc 83 mo es downward, and contact 23 moves outward until cartridgc 11 bottoms against ring 39 (H6. 1). At such time. discs 82 and 83 are spaced from the end of tube 80, thereby providng leeway for variations in the position of battery 21. The force of spring 85 insures that good electrical contact is maintained from positive terminal 22 through disc 83 and conductor 84 to conductor 57a. By virtue of its flexibility. the excess length of conductor 84 coils within tube 80. The outward deformation of contact 23 which is caused by its engagement with the outer surface of tube 80, insures that good electrical contact is maintained from negative terminal 24 through tube 80 to conductor 571:. To improve the corrosion resistance of the electrical connection. the end of contact 23 engaging the outer surface of tube 80 could be plated with nickel.

Reference is made to FIGS. 3, 5, 5A. and 5B for a detailed description of tablet dispensing assembly 59. Bore 60 is formed in a central shaft portion 86. A. the upper end of shaft portion 86, a crank portion 87 extends radially outward. A post 88 fits slidably in a bore 89 at the end of crank portion 87. The diameter of post 88 is smaller than the space between

protrusions

27 and 28. A button 90 is formed on the lower end of post 88 as a stop to prevent it from sliding upwardly out of bore 89. A leaf spring 91. which is secured to cran portion 87 by a rivet 92, engages a slot in button 90 and urges post 88 in an upward direction. Also. rotation of post 88 is prevented by this engagement. Tablet dispensing foot 68 is attached to the upper end of post 88 by a hinge 93 (FIG. 5A). Foot 68 is free to rotate about hinge 93 in a clockwise direction. from its position as viewed in PK]. 5. A lower surface 94 of foot 68 is shaped to limit the extent of rotation of foot 68. In HO. 5 foot 68 is represented at the counterclockwise limit ofits rotational path. ln FlG. 58, foot 68 is represented at the clockwise limit of its rotational path. Thus. surface 94 and the adjacent surface of post 88 function as a cam and a cam follower to limit the rotation of foot 68. The center of gravity of foot 68 lies to the left of hinge 93. as view in H0. 5, so gravity urges foot 68 in a counterclockwise direction to the position depicted in FIG. 5.

If dispenser assembly 59 happens to be oriented so foot 63 lies between adjacent stacks 20 when cartridge 11 is inserted into dispenser housing 10. foot 68 immediately moves up into channel 30 at the level ofthe bottom tablets. as shown in FIG. 1. ln this position. button 90 abuts the bottom ofcrank portion 87 and the t p of foot 63 lies below the second tablet from the bottom of the stack. However. if dispenser assembly 59 happens to be oriented so foot 68 lies'under one of stacks 20 when cartridge 11 is inserted into dispenser housing 10.

protrusions

27 and 28 prevent foot 68 from moving upward to thclevel of the bottom tablets. in such cases, cartridge 11 depresses foot 63 downwardly to push post 88 in opposition to the force of spring 91, where is remains until assembly 59 rotates sufficiently for foot 68 to be clear of

protrusions

27 and 28; then the force of spring 91 urges post 88 upwardly until button 90 abuts Page of 5 the bottom of crank portion 87 and foot 68 assumes a position at the level of the bottom tablets.

If dispenser assembly 59 happens to be oriented so foot 68 lies between adjacent stacks when cartridge 11 is removed from dispenser housing 10, foot 8 is disengaged from channel without touching cartridge 11. However, if dispenser assembly 5) happens to be oriented foot 68 lies under one of stacks 20 when cartridge 11 is removed, foot 68 contacts protrusion 27 as cartridge 11 is removed. Since foot 68 is free to rotate in a clockwise direction, it slips out of the space between

protrusions

27 and 23 and is thereby disengaged from channel 30 without being damaged.

Since the force ofgravity is used to deliver the tablets from cartridge ll to the water, it is important that dispenser housing 10 be oriented so axis l3 is approximately vertical. A universal bracket assembly illustrated in FIGS. 6 and 7 permits dispenser housing 10 to be mounted vertically at pool edges whether the mounting surface is flat or is any of the variety of bull nose copings with different shapes. A lower angular member is secured by cement and by two fasteners 101 to a flexible strip 102, which is, in turn, secured by cement to the edge of the swimming pool represented at 103. Fasteners 101 each have a head recessed in strip 102 and are fixed against rotation. For example, member 100 can be made of stainless steel, and a cloth re-inforced neoprene rubber strip could be used for member 102 to provide the desired flex without stretching so much that bracket 100 would tip forward under the weight of dispenser housing 10. A portion 100a abuts the upright side of the pool and a portion 10Gb lies above the coping. An upper angular member 204 has a portion 104 a t .11. abuts portion 190b, and is fastened to it by. two finger nuts 105, which screw onto fasteners 101. Member 104 also has a portion l04b from which vertical hinge mounting plate portions 104a extend. Portion 104a has slots 106 that permit the posi tion of member 104 to be adjusted toward or away from the pool edge relative to member 100. Hinge mounting plate portions 104: are spaced apart just enough to fit between hinge mounting protrusions 33 of body 36. Plate portions He and protrusions 33 are joined by fasteners 107, which serve as hinge points, allowing dispenser housing 10 to rotate. Thus dispenser housing 10 rotates in a clockwise direction, as viewed in FIG. 6, until protrusions 33 abut portion 100a. Member 104 is adjusted relative to member 100 until orienting side surfaces 32 are flush with portion 100a. When this adjustment is made, axis .13 ofdispenser housing 10 is vertical, assuming that portion a of member 100 is exactly vertical. If this is not the case, then member 104 is adjusted accordingly relative to member 100, so dispenser housing l!) is vertically oriented. Dispenser housing 10 is free to rotate in either direction, as viewed in H6. 6, in order to accomplish this adjustment.

The described swimming pool chemical dispensing system is designed to accommodate expendable tablet storage cartridges, i.e., cartridge 11. Thus, for example, one cartridge could carry a one monthv supply of tablets and a battery having sufficient electrical energy storage capacity to energize the dispenser actuating motor, i.e., clock motor 50, for a comparable period of time. Each month, the litl is taken oft; the used cartridge is removed upwardly from the dispenser housing, thrown away, and replaced from above with a new cartridge; and the lid is put back on. As the new cartridge is placed in the dispenser housing, the electrical connection between the battery in the cartridge and the motor in the dispenser housing is automatically established in the manner described above in connection with FIG. 4. Similarly, the tablet dispensing mechanism, i.e., foot 68, is automatically positioned at the level of the bottom tablet of each stack in the new cartridge, i.e., positioncd in channel 30, in the manner described above in connection with H6. 5. Thereafter, the motor drives the actuating mechanism in response to the energy from the battery so the tablets are dispensed sequentially one at a time over the period of a month. When the cartridge is removed at the end of the month, the electrical connection from the battery to the motor is automatically interrupted and the tablet actuating mechanism is disengaged from the cartridge without damage to the components of dispenser housing 10.

The described embodiment of the invention is only considered to be preferred and illustrative of the inventive concept; the scope of the invention is not to be restricted to such embodiment. Various and numerous other arrangements may be devised by one skilled in the art without departing from the spirit and scope of this invention. For example, it may be desirable to automatically disconnect clock 50 during certain times. it has been found that during periods of time in which the pool is not being used, such as at night, less frequent applications of water retardant are required to maintain an effective retarding layer on the water surface. Therefore, it would usually be desirable to disconnect clock 50 at night. This could be done by means of a photocell actuated electrical circuit that switches off clock 50 when the sun goes down, and switches on clock 50 when the sun comes up. Alternatively, this could be done by a gear train between assembly 59 and shaft 53 which disengages during part of each day. e.g.. every other complete revolution of shaft 53. Furthermore, the stacks of tablets in the cartridge could be arranged differently, e.g., in rows, in which case the given path that the tablet dispensing foot traverses would not be circular. While mounting the battery in the cartridge is most convenient for the user, it would also be possible to design the dispenser with the battery in the dis penser, rather than in the cartridge. Further, the tablets could take many sizes and shapes, including what are sometimes regarded as briquettes or peilets, or in general solid compact units.

What is claimed is:

l. A swimming pool chemical dispensing system comprising:

a cartridge for storing tablets of a swimming pool chemical; a dispenser housing into which the cartridge removably fits; means for attaching the housing to the edge of a swimming pool;

a battery having a positive terminal and a negative terminal disposed in the cartridge;

means disposed in the housing including an electrical clock motor for dispensing tablets stored in the cartridge into the swimming pool responsive to the power source; and

means operable when the cartridge is positioned in the housing for transmitting power from the source to the dispensing means to dispense tablets stored in the cartridge, the power transmitting means comprising an electrically conductive spring contact extending from one terminal of the battery

Claims

1. A swimming pool chemical dispensing system comprising: a cartridge for storing tablets of a swimming pool chemical; a dispenser housing into which the cartridge removably fits; means for attaching the housing to the edge of a swimming pool; a battery having a positive terminal and a negative terminal disposed in the cartridge; means disposed in the housing including an electrical clock motor for dispensing tablets stored in the cartridge into the swimming pool responsive to the power source; and means operable when the cartridge is positioned in the housing for transmitting power from the source to the dispensing means to dispense tablets stored in the cartridge, the power transmitting means comprising an electrically conductive spring contact extending from one terminal of the battery to a point at the periphery of the cartridge, an electrically conductive hollow tube mounted in the dispenser housing, the tube extending from the cartridge to the clock motor such that the spring contact engages the tube in deformation, an electrical conductor extending through the tube from the cartridge to the clock motor, an electrically conductive disc contact at the end of the tube adjacent to the cartridge positioned to engage the other terminal of the battery, spring means urging the disc contact into engagement with the other contact of the battery, and means for connecting the conductor and the tube to the clock motor.

2. The system of claim 1, in which the cartridge has a plurality of parallel vertical passages above the tube in which the tablets are stored in stacks, the passages being arranged in a circle having a center aligned with the tube; the clock motor has an output shaft below the cartridge in spaced parallel relationship to the tube; and the tablet dispensing means comprises a driving shaft with a bore that fits around the tube so the driving shaft is rotatable thereabout, means for coupling the driving shaft to the output shaft of the clock motor, a crank extending from the driving shaft outwardly to end at the circle of passages, and a tablet dispensing foot mounted at the end of the crank below the cartridge to rotate along the circle of passages responsive to the clock motor, the foot removing the tablet at the bottom of each stack in turn as the foot rotates along the circle of passages.

3. A swimming pool chemical dispensing system comprising: a cartridge having a body portion through which a plurality of parallel vertical passages are formed, the passages having bottom ends arranged to lie along a given path, the cartridge including integral tablet retaining means in alignment with the bottom end of each passage for holding up the corresponding stack such that the bottom tablet in the corresponding stack lies completely below the body portion outside the passage, and the second tablet from the bottom in the corresponding stack lies at least partially within the passage; a stack of swimming pool chemical tablets stored in each passage, each tablet being free to move downward to replace the tablet below when such tablet moves downward; a dispenser housing into which the cartridge removably fits from above; a tablet dispensing member within the dispenser housing, the member being normally disposed at the level of the bottom tablet in the stacks when the cartridge is positioned in the dispenser housing, being downwardly depressible to a point under the bottom tablet in the stacks when the member lies under one of the stacks during insertion of the cartridge into the housing, and being returnable to the level of the bottom tablet in the stacks after movement of the member out from under said one stack; and means within the dispenser housing for repeatedly moving the dispensing member along the given path to slide the bottom tablet of each stack in succession out of such stack for dispensing in a swimming pool.

4. The system of claim 3, in which the tablet retaining means for each passage comprises a first protrusion and a second protrusion extending toward each other in a direction transverse to the given path, the protrusions being spaced downwardly from the body portion of the cartridge a distance greater than the thickness of one tablet and less than the thickness of two tablets, and the foot moving means includes a post extending upwardly between the protrusions and means for attaching the foot to the top of the post.

5. The system of claim 4, in which the foot extends transverse to the given path over one of the protrusions and the attaching means is a hinge connection between the foot and the post adapted to permit the foot to slide between the protrusions when the cartridge is removed, the hinge connection being offset from the center of gravity of the foot so gravity tends to return the foot to a transverse position over one of the protrusions.

11. A cartridge for a swimming pool chemical dispensing system having a dispenser housing with a cavity into which the cartridge removably fits and a dispensing assembly with a foot that moves through the cavity in a given path, the cartridge comprising: a body portion through which a plurality of parallel vertical passages are formed, the passages having bottom ends arranged to lie along the given path; a stack of swimming pool chemical tablets stored in each passage, each tablet being free to move downward to replace the tablet below when such tablet moves downward, the tablets having a sufficiently close fit in their respective passages to axially align the tablets with their respective passages during movement; a bottom portion in which a channel is formed, the channel being slightly wider than the tablets and extending between the bottom ends of the passages along the given path so the foot of the dispensing assembly can ride in the channels; and tablet retaining means in alignment with the bottom end of each passage for holding up the cOrresponding stack such that the bottom tablet in the stack lies completely below the body portion outside the passage and the second tablet from the bottom in the stack lies at least partially within the passage, the bottom tablet in the stacks being free to drop away from the cartridge when pushed between successive retaining means by the foot of the dispensing assembly.

18. A swimming pool water retardant dispensing system comprising: a cartridge for storing tablets of the water retardant, the cartridge having a plurality of passages disposed in parallel relationship about a central axis; a stack of water retardant tablets disposed in each passage of the cartridge; a dispenser housing into which the cartridge removably fits from above such that the central axis of the cartridge is vertically oriented, the housing having a vertical opening between the bottom of the cartridge and an exit designed to lie above the water surface of the swimming pool; a motor disposed in the vertical opening of the dispenser housing underneath the cartridge in alignment with its central axis to define with the housing an annular passageway between the cartridge and the exit; and means responsive to the motor for sequentially freeing the tablet at the bottom of each stack to fall through the passageway to the exit.

20. The system of claim 18, in which the dispenser housing has an inner funnel shaped bottom portion with a first opening larger that the tablets near its apex and an outer funnel shaped bottom portion with a second opening larger that the tablets near its apex, the first and second openings of the funnels defining the exit.

24. A swimming pool chemical dispensing system comprising: a dispensing unit having a central axis along which tablets of a swimming pool chemical are adpated to fall to an exit point lying above the water surface of the swimming pool; a bracket having a stopping surface and being adapted to be attached to the edge of the swimming pool; means for pivotally mounting the dispenser unit to the bracket so that the dispensing unit is free to rotate until it abuts the stopping surface, the stopping surface being oriented so the central axis of the dispensing unit is vertical when the dispensing unit abuts the stopping surface; and means for securing the dispensing unit against rotation.

26. A water evaporation retardant dispensing system comprising: a cartridge having a body portion through which a plurality of parallel vertical passages are formed; a stack of disc-shaped water evaporation retardant tablets stored in each passage, each tablet being free to move downward to replace the tablet below when such tablet moves downward; a dispenser housing into which the cartridge removably fits; means for attaching the housing to the edge of a swimming pool; a motor in the housing having an output shaft that rotates at a slow relatively constant speed without interruption over predetermined periods of time; and a tablet dispensing mechanism in the housing, the tablet dispensing mechanism sequentially removing tablets from the bottom of each stack in turn and dispensing such tablets into the pool responsive to the motor at a rate proportional to the speed of rotation of the output shaft.

27. A swimming pool chemical dispensing system comprising: a cartridge having a body portion through which a plurality of parallel vertical passages are formed, the passages having bottom ends arranged to lie along a given path; a stack of swimming pool chemical tablets stored in each passage, each tablet being free to move downward to replace the tablet below when such tablet moves downward; tablet retaining means in alignment with the bottom end of each passage for holding up the corresponding stack such that the bottom tablet in the corresponding stack lies completely below the body portion outside the passage, and the second tablet from the bottom in the corresponding stack lies at least partially within the passage; a dispenser housing into which the cartridge removably fits from above; a tablet dispensing foot within the dispenser housing, the foot being disposed at the level of the bottom tablet in the stacks when the cartridge is positioned in the dispenser housing; means within the dispenser housing for repeatedly moving the dispensing foot along the given path to slide the bottom tablet of each stack in succession out of such stack for dispensing in a swimming pool; and means for disengaging the tablet dispensing foot from the tablet retaining means when the foot lies under one of the stacks during removal of the cartridge from the housing.

28. The system of claim 27, in which the tablet retaining means for each passage comprises a first protrusion and a second protrusion extending toward each other in a direction transverse to the given path, the protrusions being spaced downwardly from the body portion of the cartridge a distance greater than the thickness of one tablet and less than the thickness of two tablets, the foot moving means includes a post extending upwardly between the protrusions, the foot extends transverse to the given path over one of the protrusions, and the foot disengaging means comprises a hinge connection between the foot and the post adapted to pivot so the foot slides between the protrusions when the cartridge is removed.

30. The system of claim 3, in which the tablet dispensing member is spring loaded to return the member to the level of the bottom tablet after movement of the member out from under said one stack.