Abstract:
A mechanical timer to control multiple steps of a process comprising a first cam having a shaft, and a second cam having a shaft, wherein the shaft on the first cam extends into the shaft of the second cam. The rotational relationship between the first and second cams determines the length of time for at least one process step. First and second user adjustable elements are attached to the first and second cams. These user adjustable elements do not require any disassembly of the mechanical timer by the user or require any tools. A plurality of switches engage the cams to control various process steps.

Description:
FIELD OF INVENTION 
     This invention relates generally to mechanical timers, and in particular to mechanical timers used to control various water softening cycles such as backwash, brine draw, brine fill and rinse. 
     BACKGROUND OF INVENTION 
     Water softening systems of the ion exchange type often include a tank having a bed of ion exchange resin, such as a polystyrene resin. The resin material is usually non-soluble and effectively acts as a permanent anion to which exchangeable cations, such as sodium ions (Na + ) can attach. During the softening process, the hardness-causing ions in the water, such as calcium (Ca ++ ) and magnesium (Mg ++ ) ions are exchanged with the “soft” sodium ions of the resin bed, thus producing softened water. This exchange occurs because the calcium and magnesium ions have a stronger affinity toward the resin bed than do the sodium ions. After prolonged contact of the resin bed with hard water, however, the ion exchange capacity of the resin bed diminishes, and regeneration of the resin bed must be performed. 
     Regeneration of the resin bed is normally performed in distinct steps during what is called the regeneration cycle. First, the bed is cleansed during a backwash cycle, where the normal water flow across the resin bed is reversed to expand the resin bed and remove any deposits that may be trapped in the resin bed. Second, a brine solution (i.e., an aqueous solution of sodium chloride or the like) from a separate brine tank is introduced to the resin bed. When the brine contacts the resin bed, the aforementioned ion exchange process is reversed, i.e., the “hard” ions in the resin bed are replaced with “soft” ions from the brine solution. Thereafter, a rinse cycle is normally provided to wash the brine from the resin bed. Lastly, the brine tank is refilled to form brine for the next regeneration cycle. 
     It is known to utilize mechanical timers to control the various regeneration cycles. Additionally, due to the particular demands placed upon the water softening system, it is often desirable for a user to vary the length of time for each individual regeneration cycle to adjust for various tank sizes and volumes of resin To accomplish this, mechanical regeneration timers may use movable fingers to time the individual regeneration cycles, such as the timer disclosed in U.S. Pat. No. 5,590,687. However, such timers often require disassembly or use of tools by the user to adjust the individual cycle times. This usually entails the removal or loosening of covers, screws, or other fasteners to access and/or move the regeneration cycle time adjustments. Disassembly of this nature is normally awkward and time consuming for users of water softening systems. Thus, there is a need for a mechanical timer to control water softener cycle times that allows users to easily and efficiently adjust the individual cycle times without any disassembly of the timer mechanism or use of tools. 
     These and other needs will become apparent upon a further reading of the following detailed description taken in conjunction with the drawings. 
     SUMMARY OF THE INVENTION 
     In one form of the invention, the aforementioned needs are fulfilled by a mechanical timer to control multiple steps of a process comprising a first cam having a shaft, and a second cam having a shaft, wherein the shaft on the first cam extends into the shaft of the second cam. The rotational relationship between the first and second cams determines the length of time for at least one process step. First and second user adjustable elements are attached to the first and second cams. These user adjustable elements do not require any disassembly of the mechanical timer by the user or require any tools. A plurality of switches engage the cams to control various process steps. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a mechanical timer assembly for regeneration of a water softening unit; 
     FIG. 2 is an exploded view of a regeneration timer assembly; 
     FIG. 3 is a perspective view of a brine cam; 
     FIG. 4 is a bottom view of FIG. 3; 
     FIG. 5 is a front view of FIG. 3; 
     FIG. 6 is a top view of FIG. 3; 
     FIG. 7 is a perspective view of a backwash cam; 
     FIG. 8 is a bottom view of FIG. 7; 
     FIG. 9 is a front view of FIG. 7; 
     FIG. 10 is a top view of FIG. 7; 
     FIG. 11 is a perspective view of a base cam; 
     FIG. 12 is a bottom view of FIG. 11; 
     FIG. 13 is a front view of FIG. 11; 
     FIG. 14 is a top view of FIG. 11; 
     FIG. 15 is a perspective view of a gear; 
     FIG. 16 is a perspective view of an adjustment dial; 
     FIG. 17 is a perspective view of a pointer; 
     FIG. 18 is a perspective view of an assembled regeneration timer; 
     FIG. 18 b  is another perspective view of an assembled regeneration timer; 
     FIG. 19 is an exploded view of a mechanical timer assembly for regeneration of a water softening unit; 
     FIG. 20 is a rear perspective view of the mechanical timer of FIG. 19 in an assembled state; 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     While the present invention is capable of embodiment in various forms, there is shown in the drawings and will be hereinafter described a presently preferred embodiment with the understanding that the present disclosure is to be considered as an exemplification of the invention, and is not intended to limit the invention to the specific embodiment illustrated in the drawings and described herein. 
     For purposes of illustration, and not limitation, a mechanical control mechanism for valve control, designated generally as reference numeral  100  in FIG. 1, includes a day timer  102 , a twenty-four hour timer  104 , and a regeneration cycle control timer  106 . The day timer  102  and twenty-four hour timer  104  are of known construction and do not separately form part of the present invention. As such, the day timer  102  and twenty-four hour timer  104  are not discussed in detail herein. Suffice it to say, the day timer  102 , twenty-four hour timer  104 , and regeneration control timer  106  all work in conjunction to time the regeneration of a water softening system. 
     As shown in FIG. 2, the regeneration cycle control timer  106  comprises a pointer  108 , a dial  110 , a gear  112 , a base cam  114 , a backwash cam  116  and a brine cam  118 . The brine cam  118  as shown in FIGS. 2 through 6 comprises an annular disc  120  having a top surface  120 A, bottom surface  120 B (See FIG.  4 ), and an upper cam flange consisting of three segments  122 A,  122 B and  122 C, conforming to the outer periphery of the disc  120 . Preferably, segment  122 A is wedge shaped to provide added strength. As discussed more fully herein, the upper flange segments  122 A,  122 B and  122 C, when used in conjunction with the other cams, as described herein, create windows therebetween through which a cam follower as shown in FIG. 20 may enter. A lower cam flange  128  conforming to the outer periphery of disc  120  is located on the bottom surface  120 B. Cam follower  232  as shown in FIG. 20 may ride on the surface of flange  128 . The brine cam  118  also includes a shaft  130  attached to the center of the annular disc  120 , and extending away from disc  120 . The shaft  130  includes a bore  132  and a notch  134 . 
     Similar to the brine cam  118 , the backwash cam  116  as shown in FIGS.  2  and  7 - 10  includes an annular disc  136  having a top surface  136 A, bottom surface  138 B (See FIG. 8) and a cam flange consisting of three segments  138 A,  138 B and  138 C conforming to the outer periphery of the disc  136 . As can be appreciated from the drawings, disc  136  is a smaller diameter than disc  120 , so as to enable the backwash cam to sit within the brine cam  119  when the regeneration timer  106  is fully assembled. Segment  138 A is preferably wedge shaped to provide added strength. The flange segments  138 A,  138 B and  138 C create windows therebetween through which a cam follower  230  as shown in FIG. 20 may enter. Wedge shaped cutout  144  provides for free movement of the wedge shaped cam segment  122 C of brine cam  118  within the wedge shaped cutout when the regeneration timer assembly is assembled as shown in FIGS. 18 and 20. The backwash cam  116  also includes a shaft  146  attached to the center of the annular disc  136 , and extending away from disc  136 . The shaft  146  includes a bore  148 , a top surface  149  and a notch  150 . It should be appreciated that the diameter of the bore  148  on the backwash cam  116  is approximately the diameter of the shaft  130  of the brine cam  118 , thereby allowing the shaft  130  to telescope into the bore  148  for rotational movement therein. 
     The base cam  114  as shown in FIGS. 2, and  11 - 14 , includes an annular disc  156  having a top surface  156 A, bottom surface  156 B (See FIG.  12 ), and cam flange segment  158  conforming to the outer periphery of the disc  156 . As can be appreciated from the drawings, disc  156  is of a larger diameter than discs  136  and  132 , thereby allowing the brine cam  118  and backwash cam  116  to be enveloped by flange  158  when in an assembled position as shown in FIG.  18 . The flange  158  has a window  160  through which a cam follower  230  may enter as shown in FIG.  20 . The base cam  114  also includes a shaft  164  attached to the center of the annular disc  156 , and extending away from the flange  158 . The shaft  164  includes a top surface  165 , bore  166  and a notch  168 , the notch having a ledge  169 . As can be appreciated by viewing the drawings, the diameter of the bore  166  is approximately the diameter of the shaft  146  of the backwash cam  116 , thereby allowing the shaft  146  to telescope into the bore  166  for rotational movement therein. It should be appreciated at this point that although three cams are depicted herein, more or less cams can be used to practice the invention herein, depending on the particular application desired. 
     The gear  112 , as shown in FIGS. 2 and 15, includes an annular disc  174  having a top surface  174 A. The outer periphery of the disc  174  contains a plurality of gear teeth  176  and an arcuate notch  177 . The gear  112  also includes a shaft  178  attached to the disc  174 . The shaft  178  has a bore  180 , which includes a key  182 . The key  182  extends from a top surface  184  of the shaft  178  and partially into the bore  180 , and terminates in a ledge (not shown). Extending radially outwardly from shaft  178  is a pointer  188 , which is attached to the gear  112 . The pointer  188  includes a tooth  189  for selectively engaging notches  191 A on dial  110  (FIG.  12 ). 
     The diameter of bore  180  is approximately the diameter of shaft  164 , thereby allowing shaft  164  to be telescoped into bore  180  until ledge  169  meets the ledge of key  182 , at which time the top surface  184  of shaft  178  is flush with the top surface  165  of shaft  164 , and the gear  112  and the base cam  114  are axially spaced apart. 
     The dial  110  as shown in FIGS. 2 and 16 is annular in shape and has indicia  190  and  191  on an upper surface  110 A thereof. In a preferred embodiment, the indicia  190  represents a salt setting in pounds, and indicia  191  represents a backwash setting in minutes. The dial  110  also includes notches  190 A corresponding to indicia  190  and notches  191 A corresponding to indicia  191 . An aperture  192 , located generally in the center of dial  110 , includes a key  194 . The key  194  is engageable with the notch  150  of backwash cam  116  to provide conjoint rotation between the dial  110  and the backwash cam  116 . 
     The pointer  108  as shown in FIGS. 2 and 17 can take any convenient shape, such as the depicted teardrop shape, and comprises a first aperture  196 , which includes a key  197 . The pointer  108  also includes a second aperture  198  which may be used to view the indicia  190  on the dial  110  therethrough, and a tooth  199  for selectively engaging notches  190 A. As those skilled in the art will appreciate, although a tooth and notch arrangement is depicted herein for selective engagement, any other structure capable of selective engagement may be utilized, such as a spring loaded ball and socket configuration. Preferably, the pointer  108  is used to indicate the current salt dosage. The key  197  is engageable with the notch  134  of brine cam  118  to provide conjoint rotation between the pointer  108  and the brine cam  118 . 
     To assemble the regeneration timer as shown in FIG. 18, the shaft  130  of brine cam  118  is first inserted into the bore  148  of backwash cam  116 . Next, shaft  146  of backwash cam  116  is inserted into the bore  166  of base cam  114 . At this point, the backwash cam is sandwiched in between brine cam and base cam as shown in FIG. 18, and the various cam flanges on the brine, backwash and base cam cooperate to form adjustable windows  160 - 163 . 
     Next, the shaft  164  of base cam  114  is inserted into the bore  180  of gear  112 , making sure to align the key  182  with the notch  168 . At this point, the shaft  146  of the backwash cam  116  is protruding from the bore  166  of the base cam  114  so as to expose notch  150 , and the shaft  130  of brine cam  118  is protruding from the bore  148  of backwash cam  116  so as to expose notch  134 . 
     The shaft  146  is then inserted into the aperture  192  of the dial  110 , making sure to align notch  150  and key  149 . It should be noted that although a key structure is depicted for joining certain elements for conjoint rotation, it should be understood that any joining mechanism such as splines, pins or adhesives may be used. 
     Lastly, the shaft  130  is inserted into the aperture  196  of the pointer  108 , making sure to align notch  134  and key  197 . Preferably a fastener, such as a screw  200  shown in FIG. 19, is inserted into bore  132  to hold the regeneration timer assembly together. 
     It should now be appreciated that when the pointer  108 , dial  110 , gear  112 , base cam  114 , backwash cam  116 , and brine cam  118  are assembled as described above, apertures  196 ,  192  and  180  and bores  166 ,  148 , and  132  are axially aligned. It should further be appreciated that base cam  114 , backwash cam  116  and brine cam  118  are independently rotatable with respect to each other when in an assembled position. 
     Preferably, the regeneration timer assembly is assembled within a timer plate  201  as shown in FIG.  1 . In such a configuration, the pointer  108 , dial  110  and gear  112  are located on the top surface  201 A of timer plate  201 , and the base cam  114 , backwash cam  116  and brine cam  118  are located on the bottom surface  201 B of timer plate  201 , as shown in FIG.  20 . In such a configuration, shafts  130 ,  146 , and  164  pass through an aperture  202  in timer plate  201  as seen in FIG.  19 . 
     Also located on or adjacent the top surface  201 A of timer plate  201  is the day timer  102 , twenty-four hour timer  104 , gear cluster  204  and regeneration actuator arm  206 . Drive motor  208  on bottom surface  201 B of timer plate  201  drives gear cluster  204  via drive motor gear  209  (See FIG.  1 ). The gear cluster  204  in turn provides rotational movement to the day timer  102 , twenty-four hour timer  104  and regeneration timer  106 . Preferably, the drive motor is a 24 volt 60 hertz motor that is driven at 1/30 rotations per minute. 
     Gear  210  has gear teeth  210 A and an axle  212  that is placed within slot  214 , as best seen in FIG.  19 . The end of axle  212  protrudes from the bottom surface  201 B of timer plate  201  and contains an annular recess  215 . Spring  216  is anchored on one end to aperture  218  (FIG. 20) and engages on its other end the annular recess  215  to bias the axle  212  against one side of the slot  214 . Spring  216  is preferably of a sufficient tension to bias the axle  212  against one side of the slot  214  during normal operation, yet allow the axle  212  to temporarily slide within the slot  214 , under conditions as will be described below. As depicted in FIG. 1, gear  210  is driven by the drive motor gear  209 , and engages the gear teeth  176  on gear  112  to rotate the regeneration timer  106 , such as in a clockwise direction when viewed from the top surface  201 A of timer plate  201 . 
     Also included on the back side  201 B of timer plate  201  are cam switches  220  and  222  as shown in FIGS.  19  and  20 . Preferably, cam switches  220  and  222  are micro-switches that include cam followers  230  and  232  respectively. In a preferred embodiment, cam switch  220  controls the timing of all regeneration cycles and cam switch  222  provides an indication of timer  106 &#39;s home position, causing the device driven by this timer to return to home in the event of a malfunction in positioning. However, it should be understood that the function and/or the position of the cams and cam switches may be varied if desired. 
     Operation of the present invention as described above allows a user of a water softening system to adjust easily and efficiently various parameters of a regeneration cycle. In accordance with the invention as set forth herein, a user may vary the parameters for the brine draw, brine fill and backwash regeneration cycles by adjusting the user-accessible settings on the regeneration timer assembly  106  without any disassembly of the mechanical timer assembly or any use of tools. In particular, the user may rotate the pointer  108  with respect to the dial  110  to set a desired salt dosage as indicated by indicia  190 . When this is done, the shaft  130 , brine cam  118 , and cam segments  122 A,  122 B, and  122 C rotate conjointly therewith because of the shaft  130  being attached to pointer  108  via notch  134  and key  197 . 
     The length of the brine draw cycle is determined by the window  161  formed between cam segment  122 C on brine cam  118  and cam segment  138 A on backwash cam  116 . This window increases in size as pointer  108  is adjusted toward higher salt dosages on indicia  190 . At the same time the brine fill time is determined by the window  163  formed between cam segment  122 A on brine cam  118  and cam segment  138 C on backwash cam  116 . This window likewise increases in size as pointer  108  is adjusted toward higher salt dosages. These windows are closed completely when the salt dosage is set to zero. In a preferred embodiment however, a pointer stop  236  is included on dial  110  to prevent a zero salt dosage. A zero salt dosage is undesirable because without a brine solution passing over the resin bed, no regeneration will occur. In a preferred embodiment, the salt settings are in pounds and in five (5) pound intervals from zero (0) to (30) pounds. 
     The backwash time is set in a similar fashion by moving dial  110  with respect to gear  112 . As the dial  110  is moved, shaft  146  to which the dial is connected rotates conjointly therewith, thus rotating backwash cam  116  and segment  138 A. The pointer  188  on gear  112  indicates the current backwash time by pointing to indicia  191 . As shaft  146  is rotated, cam segment  138 A is rotated within flange  158  to adjust the size of window  160  formed between cam segment  138 A and flange  158 . When the backwash time is set to zero, the window is totally closed and when the backwash time is set to full, the window is at its maximum size. In a preferred embodiment, however, a pointer stop  238  as best seen in FIG. 16 is provided on the outer periphery of the dial  110  to prevent the pointer  188  from reaching a zero backwash setting. A zero backwash setting is undesirable because without a backwash cycle, residue may remain on the resin bed, thus preventing effective regeneration. In a preferred embodiment, the backwash settings are in five minute intervals from zero (0) to fifteen (15) minutes. As those skilled in the art will appreciate, the cam structure described herein may take a variety of forms that allow for a window between two points on a cam to be adjusted by a user, including stacked (as opposed to nested)cam structures having discs of equal size with arcuate wedges attached on a surface thereof to adjust window sizes on other cams. 
     After the user has chosen the desired regeneration cycle parameters on the regeneration timer  106  and chosen the desired day(s) and time of regeneration by adjusting the day timer  102  and the twenty-four hour timer  104 , the user may leave the timer mechanism unattended. While unattended, the timer motor  208  will turn at a pre-determined rate (preferably 1/30 rotations per minute) to drive the gear cluster  204  and, in turn, the day and twenty-four hour timers,  102  and  104 . When regeneration is not occurring, the regeneration timer  106  remains in an idle position, where gear  112  is not engaged with gear  210 . This occurs when arcuate notch  177  on gear  112  is in between the respective axes of the gear  112  and the gear  210 . 
     When the user-selected day and time for regeneration occurs, the day timer  102  will actuate the regeneration actuator arm  206  in a direction toward the regeneration timer  106 . Alternatively, the actuator arm may be manually actuated by the user for instant regeneration, thereby bypassing the day and twenty-four hour timers  102  and  104 . 
     The actuator arm  206 , upon actuation, comes into contact with the pointer  188 , thereby urging gear  112  in a clockwise direction. As the gear  112  is rotated in a clockwise direction, gear teeth  176  come into contact with gear teeth  210 A on gear  210 . To allow for proper meshing of gear teeth  176  and  210 A, drive gear  210 , slides within the slot  214  in a direction away from the regeneration timer  106 . Once proper meshing of the gears  176  and  210 A is achieved, spring  216  retracts the gear  210  to its original position. 
     With the gear  112  engaged with gear  210 , the timing motor  208  drives the gear  210  in a counter-clockwise direction, and hence the regeneration timer  106  in a clockwise direction. As one skilled in the art will appreciate, the entire regeneration timer  106  turns as one unit due to the interlocking nature of the pointer  108 , dial  110 , gear  112 , base cam  114 , backwash cam  116  and brine cam  118 . Thus, as gear  112  is turned, base cam  114  rotates conjointly therewith due to notch  168  and key  182 . The tooth  189 , which is integral with gear  112 , causes dial  110  to rotate conjointly with the gear  112  due to the tooth  189  being selectively engaged with notches  191 A. Consequently, the dial  110  causes backwash cam  116  to rotate conjointly therewith due to notch  150  and key  194 . Lastly, dial  110  causes pointer  108  to rotate conjointly therewith due to tooth  199  selectively engaging notches  190 A. Consequently, brine cam  118  rotates conjointly with pointer  108  due to notch  134  and key  197 . 
     Immediately after gears  112  and  210  mesh and the entire regeneration timer mechanism  106  begins rotating as one unit, the cam follower  230  of switch  220  falls into window  160  as best seen in FIG.  20 . This triggers a motor (not shown), or other actuator device, to open a valve (not shown) which begins the backwash process. As is known in the art, all regeneration cycles are controlled in a similar fashion. The backwash cycle continues until the cam follower  230  is lifted out of the window  160  by reaching the end of window  160  due to the continued rotation of the regeneration timer  106 . As stated above, the size of the window  160  is dictated by easily-accessible user settings. 
     As the regeneration timer  106  continues in a clockwise direction, cam follower  230  of switch  220  falls into the window  161 . This causes the brine draw cycle to begin. The brine draw cycle continues until cam follower  230  is lifted out of window  161  by reaching the end of window  161  due to the continued rotation of the regeneration timer  106 . Again, as stated above, the size of the window  161  is dictated by easily-accessible user settings. 
     After the brine draw cycle, the cam follower  230  of switch  220  falls into window  162 , which causes the rinse cycle to begin. The rinse cycle continues until the rotational movement of the regeneration timer  106  causes the cam follower  230  to reach the end of window  162  and lift out of window  162 . Unlike windows  160  and  161 , window  162  in a preferred embodiment cannot be varied in size by user settings. However, it should be appreciated that the size of window  162  could also be varied with similar structures used to vary windows  160  and  161 . 
     Lastly, after the rinse cycle, cam follower  230  of switch  220  falls into window  163  to start the brine fill cycle, which refills the brine tank. The brine fill cycle continues until the rotational movement of the regeneration causes the cam follower  230  to reach the end of window  163  and lift out of window  163 . It should be appreciated that brine draw window  161  and brine fill window  163  are both adjusted by a single movement of brine cam  118 . Thus, when a user changes salt dosage by moving pointer  108 , the appropriate adjustments to brine draw and brine fill times occur automatically. It should also be appreciated that an adjustable window system as described herein could be used to provide an independent, user-settable, window for the brine fill cycle. 
     After the brine fill cycle is complete, the regeneration timer  106  continues to rotate until arcuate notch  177  encounters gear  210 , thus disengaging the regeneration timer  106  gear  112  from gear  210 . 
     Cam follower  232  of switch  222  is designed to be engaged by cam flange  128  of brine cam  118 , as best seen in FIG. 20, to provide a homing feature. Follower  232  climbs onto flange  128  as the regeneration timer  106  nears the end of its cycle. At this point the device driven by this timer (i.e., a valve actuating motor) should have reached its home, or service, position due to the actions of switch  220  and follower  230  as described above. However, if, for any reason, the device has not reached its home position when follower  232  climbs flange  128 , switch  222  will operate to drive the device to its home position, thereby resynchronizing the mechanism. 
     The foregoing description of a preferred embodiment of the invention has been presented for purposes of illustration and description, and is not intended to be exhaustive or to limit the invention to the precise form disclosed. The description was selected to best explain the principles of the invention and their practical application to enable others skilled in the art to best utilize the invention in various embodiments and various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention not be limited by the specification, but be defined by the claims set forth below.