US3914951A

US3914951A - Defrost timer for indicating refrigerator warranty

Info

Publication number: US3914951A
Application number: US497337A
Authority: US
Inventors: John H Heidorn
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1974-08-14
Filing date: 1974-08-14
Publication date: 1975-10-28
Anticipated expiration: 1992-10-28

Abstract

An automatic defrost timer including a spiral cam coacting with switch contacts is provided with a pawl means for engagement with a ratchet wheel mechanism having an eccentric cam and ratchet wheel advance cam follower imparting rotation to an indicating wheel visual indication means in the form of coded segments thereon, wherein each segment is associated with a certain predetermined warranty time interval indicating the elapsed time during which a refrigerator has been in service. The rotating indicator wheel, when viewed through a window in the timer switch housing, has, for example, a first colored segment indicating the refrigerator is operating during a first period of its warranty, a second colored segment indicating that a second period of the warranty is in effect while a third colored segment is designed to be permanently visible when the total warranty period has expired.

Description

United States Patent 11 1 1111 3,914,951

Heidorn 1 Oct. 28, 1975 DEFROST TIMER FOR INDICATING Primary ExaminerWi1liam F. ODea REFRIGERATOR WARRANTY Assistant Examiner-Peter D. Ferguson [75] Inventor: John H. Heidom, Dayton Ohio Attorney, Agent, or F zrm-Edward P. Barthel 73] Assignee: General Motors Corporation,

Detroit, Mich. [57] ABSTRACT Filed! g- 1974 An automatic defrost timer including a spiral cam 00- [211 App. No; 497 337 acting with switch contacts is provided with a pawl means for engagement with a ratchet wheel mechanism having an eccentric cam and ratchet wheel ad- 1 vance cam follower imparting rotation to an indicating 200/38 B wheel visual indication means in the form of coded III. GL2 segments the eqn wherein each segment is associated 1 Fleld of Search 58/ 147, 145 with a certain predetermined warranty time interval 231, 200/33 373 indicating the elapsed time during which a refrigerator has been in service. The rotating indicator wheel, References Clted when viewed through a window in the timer switch UNITED STATES PATENTS housing, has, for example, a first colored segment indi- 2,595,967 5 1952 MCCIOy 62/234 x catmg the refrigerator is Operating during a first 2,690,526 9/1954 Morrison 62/115 x iod of its Warranty 8 Second Colored Segment indicat- 2,803,30O 8/1957 Warkentien 58/147 X ing that a second period of the warranty is in effect 2,975,612 3/1961 Everard 62/155 while a third colored segment is designed to be perma- 3,071,208 1/1963 Rasch et a1. 58/145 R nenfly visible when the total warranty period has expired.

4 Claims, 7 Drawing Figures w ZE 39 I p I0 1 in:

Til 1 f 1 a I I at- DEFROST TIMER FOR INDICATING REFRIGERATOR WARRANTY I This invention relates to an improved timer device for use in a refrigeration system and is directed to a refrigerator automatic defrost timer incorporating visual means on an indicator wheel for displaying the elapsed time of the warranty period for the refrigerator.

In the appliance industry there has long been a need for a small, tamper proof and inexpensive timer to be incorporated with each appliance, such as a refrigera tor, to indicate accurately the actual elapsed time the appliance has been in operation. The present invention is directed to a warranty elapsed time device which may be incorporated with a standard refrigerator defrost timer of the type disclosed, for example, in the US. Pat. No. 2,975,612 issued Mar. 21, 1961 to J. J. Everard.

It is therefore an object of this invention to provide visual means incorporated with a known timing device for use in a refrigeration system for notifying the owner or serviceman of the approximate length of the time the appliance has been in operation so that it may be readily determined whether the applicable warranty provisions are in effect.

It is yet another object of the invention to provide an improved cam driven automatic defrost timer of known construction for use with a refrigerator incorporating a spring pawl and ratchet mechanism including a pair of independently rotatable primary and secondary ratchet wheels, having identically pitched counting teeth, mounted for rotation on a common spindle together with intermediate eccentric cam operating a cam follower keeper and ratchet advance such that upon the timer electrical contact blade spiral cam making one complete revolution every selected number of hours of a defrosting cycle the primary and secondary ratchet wheels will be intermittently advanced by a contact blade pawl and the cam follower advance respectively, to rotate an indicator wheel having a plurality of color segments thereon successively visible through the cover of the timer housing such that each color segment indicates a different stage of the warranty period of the refrigerating appliance.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown.

In the drawings:

FIG. 1 is a view of the defrost timer with the cover removed and with the parts in their normal position;

FIG. 2 is a vertical sectional view of the defrost timer taken substantially on the line 2-2 of FIG. 1, partly in section;

FIG. 3 is a horizontal sectional view taken substantially along the line 33 of FIG. 1, partly in section;

FIG. 4 is an exploded view of the cam follower and primary ratchet wheel cam;

FIG. 5 is a perspective view of the ratchet spring;

FIG. 6 is a perspective view of the contact arm ratchet actuator;

FIG. 7 illustrates schematically one control system of the invention.

Referring to the drawings in detail, the improved control means of this invention is generally indicated by the reference numeral 10 and comprises a housing means 11 having a chamber 12 therein having a base ing the chamber 12. The cam 20 in the disclosed embodiment is an eight-hour cam which turns off the refrigerator compressor and blower, and at the same time energizes the defrost heater once every eight hours. It will be understood, however, that the cam could be a twelve-hour, twenty-four hour or any other specified time cycle desired without departing from the scope of the invention.

Three contact arms are provided and indicated by the

reference numerals

31, 32 and 33, and are respectively, the defrost or heater arm 31, a common or power supplying central arm 32 and a compressor arm 33. A line terminaLis provided at 34 for supplying power to the power supply arm 32 via the timer motor as seen in the schematic of FIG. 7. The contacts of the arms are arranged in a single pole-double throw arrangement wherein the common 32 and defrost 31 contacts are normally open, and close upon initiation of a defrost cycle. The arms are supported in the terminal box 35 of the casing to provide four substantially parallel

male terminal members

31, 32, 33' and 34 for connection to a suitable terminal block (not shown) in the machine compartment of a refrigerator.

The three contact means or contact carrying blades or

arms

31, 32 and 33 are biased toward the right as viewed in FIG. 1. As explained in the above-mentioned US. Pat. No. 2,975,612 to Everard, the heater arm 31 may be most heavily biased and it is to be noted that the heater arm 31 is spaced, by means of an insulating spacer 36, from the compressor arm 33 and that shoulders are provided on the insulating spacer 36 so that the biased heater arm 31 transmits its motion to the compressor arm 33 and thus biases the arm 33 to the right when in the position shown in FIG. 1. The compressor arm 33 is inherently biased toward the left with reference to the heater arm 31, whereas the heater arm is more heavily biased to the right than the compresssor arm 33 so that the upper end of the arm 33 rides on the spiral cam 20 when itis pressed to the left by the cam as viewed in FIG. 1. The heater arm 31 will be forced to the left and will be out of contact with the power supplying common central arm 32. On the other hand, as soon as the compressor arm 33 drops-off the trailing edge of the cam at notch 41, the arms assume the position in which the compressor arm 33 is moved out of contact with the power supplying arm 32 and in which the heater arm 31 is in electrical contact with the power supplying common arm 32.

It is to be noted that the cam 20 is provided with the abrupt notch 41 such that as the compressor arm 33 drops off the cam the heater or defrost contact arm 31 is now in contact with the power supplying common arm 32 and consequently, as seen in FIG. 7, the defrost heater 37 is put into operation since its defrost limiter thermostat 38 is closed. The thermostat 38 remains closed and the heater 37 imparts the air in the refrigerator in the usual way and causes rapid defrosting. The above description is of the known defrost timer of the type disclosed in the mentioned. Everard patent, and the following description is of applicants warranty indicating mechanism which is uniquely incorporated with the known defrost timer. g

The cover plate 23, supported on peripheral shoulder 39, preferably provides an upper bearing recess 40 on its undersurface for receiving the end of pinion gear 42 bottom or base wall 13 of the housing. A lower primary ratchet wheel 54, having counting teeth 55, equal in number to the upper wheel teeth 48, is carried by and revolves independently on the lower end of the fixed spindle 52 in axial spaced relation with upper wheel 46.

Cam means in the form of an upwardly extending eccentric hub cam 62 fixed, as by being integrally molded. on the inner or upper surface of lower wheel 54 which serves as a spacer between the wheels. In the intermediate space between the wheels applicant provides cam follower means 63 which, as best seen in FIG. 4, includes an elongated rounded-end aperture 64 adapted to slide rotatably about the cam 62 causing eccentric movement of the cam follower.

As seen in FIGS. 1 and 4 the cam follower 63 journal arm 64 having integrally formed at its outer end a drive pin journal bearing 66 which is provided with an elongated axial slit 68 to receive a rolled drive pin of spring means to be described. On the opposite end of the cam follower 63 there is provided an integrally molded ratched wheel advance bar 69 which extends axially parallel with the axis of the drive pin journal bearing and has a suitable cross section contoured to engage successive teeth of the secondary ratchet wheel 46 to effect counterclockwise tooth-by-tooth rotation thereon in a manner to be explained. It will be noted that while the counting

teeth

48 and 55 on both the upper and lower ratchet wheels are shown equal in number and identically pitched for the desired time in the disclosed form, other arrangements wherein wheels have unequal teeth are within the scope of the invention.

Referring now to FIG. 5, there is shown cam follower spring biasing means in the form of a generally angleshaped ratchet spring 70 having one leg forked or bifurcated to provide

spring fingers

71 and 72. The ratchet spring 70 is connected to the cam follower journal 66 by having the end of its other leg 74 rolled into a pin 73 telescoped into the journal bore 67 with leaf spring leg 74 received in journal slit 68. The leaf spring leg 74 is integral with an anchor plate 76 of generally rectangular shape which is retained in the housing integral block 78 by insertion in one portion of an L-slot 79 in block 78 with the fixed end of the normally extending

spring fingers

71 and 72 received in the L-slot tangent to housing boss member 77. Angularly deformed obtuse ends or spring tabs 82 and 84, at the free ends of the

fingers

71 and 72 respectively, are each disposed at a suitable angle such that the obtuse spring ends engage

teeth

48 and 55 of their associated

ratchet wheels

46 and 54. The purpose of the

spring fingers

71 and 72 is to engage the teeth of

ratchet wheels

46 and 54 respectively, to prevent reverse rotationthereof. Thus, the bifurcated

spring fingers

71 and 72 serve as a pair of check springs having identical

obtuse ends

82 and 83 spaced so that they will always engage

corresponding ratchet teeth

48 and 55 to prevent clockwise rotation of the ratchet wheels as viewed in FIG. 1.

In operation the primary or lower ratchet wheel is adapted to be rotated counterclockwise, as viewed in FIG. 1, by means of its ratchet teeth 55 being engaged by cooperating pawl 88. The pawl 88 is lanced from one side edge of resilient cantilever arm 90 integral with the compressor switch blade 33, forming a T- shaped member with blade 33, so as to extend transversely between the spiral cam 20 and the

ratchet wheels

46 and 54. The pawl 88 is bent downwardly out of the plane of the arm 90 toward the blade 33 forming an acute angle with arm 90. The resilient lever arm 90 is tangent to and contacted by the spiral surface 91 of the cam 20 whereby the spring action of arm 90 of T- shaped blade 33 causes the pawl 88 to be biased into a tooth notch of the primary ratchet wheel whereby the pawl 88 is adapted to advance the primary ratchet wheel 54 counterclockwise in a tooth-by-tooth manner each time the cam 20 rotates a full 360.

In the disclosed embodiment the pawl 88 is adapted to advance the primary ratchet wheel 54 counterclockwise through a 10 tooth segment each time the cam 20 completes one 360 revolution during an eight hour period or a total of 30 per day. Thus, each time the cam 20 completes a 360 rotation and causes the contact end of the compressor blade 33 to fall off the spiral cam notch 41 the arm 90 moves to the right, as viewed in FIG. 1, momentarily causing pawl 88 to be disengaged with one of the teeth 55 and engage the next succeeding tooth. After the defrost period is completed the defrost limiter thermostat 38 opens to again energize the timer motor 14 to drive spiral cam 20 through another cycle. The rotation of the spiral cam 20 causes the compressor blade 33 and its reciprocating cantilever arm 90 to move to the left a sufficient distance to allow the advance of the primary ratchet wheel 54 through an arcuate distance equal to the length of one ratchet tooth. It will be noted that the pressure exerted by spiral cam surface 91 on actuating 'arm 90 insures its pawl 88 is biased into contact with the primary ratchet wheel 54. During the next succeeding eight hour defrost cycle the spring leg obtuse end 83 acts as a stop to prevent reverse of clockwise rotation of the primary ratchet wheel 54, while. the compressor switch blade 33 rides upon the clockwise rotating spiral cam surface 91 moving pawl 88 and arm 90 toward the left to advance the primary wheel one tooth per cycle.

The pinion gear 42 of the secondary ratchet wheel 46 meshes with the teeth of an indicator wheel, generally indicated at 94, rotatably mounted on the underside of cover 23 by means of its hub 96 joumalled in cover aperture 97 and retained by ring 98 in a tamper proof manner such as by heat riveting. The upper surface of the indicator wheel is divided into three pie-shaped or radial segments 101, 102 and 103 of differing arcuate extent with each of the segments having distinguishing marking which in the preferred form is provided by a color code with different colors representing a predetermined time interval during the Warranty period of the appliance.

As seen in FIG. 1 of the disclosed form the indicator is partially visible through a window segment 106 in cover 23, shown in phantom in FlG. 1, during the first year the' appliance is in operation, indicating that the first stage or periodof the warranty is in, effect. In the formshown the blue segment covers a radial segment of about one-sixth or 60 of the wheel 94. The intermediate segment 102 is shown colored green and portions thereof will be visible through window 106 during the second, third, fourth and fifth years the appliance is oplower 64 into resilient engagement with the teeth 48 of the secondary wheel the previously mentioned flexed leaf spring 74 acts via its rolled pin 72 in journal 66 to allow pawl 88 to advance the primary ratchet wheel 54 and rotate its associated eccentric cam 62 while the secondary ratchet wheel is held fixed. The elongated aperture 64 of the cam follower provides freedom of radial movement with sufficient clearance to enable the follower bar 69 to be spring biased while the cam 64 operates in aperture 69 to achieve a fast counterclockwise return of the bar 69 to engage the next tooth. When the tooth-by-tooth advancement of the primary wheel by the pawl 88 reaches 36, or one complete revo lution, the eccentric cam 62 causes cam follower 64 and its actuator bar 69 to rotate or pivot in a clockwise direction a predetermined distance to ride-over and past its engaged tooth a sufficient distance to engage the next succeeding tooth and thereby advance the secondary ratchet wheel 46 in a counterclockwise direction one tooth for every 360 revolution of the primary wheel 54. As the primary wheel 54 rotates once every twelve days the secondary wheel 46 makes about 30.4 rotations per year or advances 31 teeth every 372 days (31 X 12 372). As each tooth of the wheels intercepts an angle of about it will be seen that the secondary wheel moves through an arcuate distance of about 310 or about 86% of a complete 36 tooth rotation.

In the preferred embodiment the drive pinion gear 42 has ten teeth while the indicator wheel 94 has its teeth 112 cut at a pitch of 50 teeth per 360of revolution providing a 5:1 gear ratio. Thus, the indicator wheel 94 revolves through an angle of about 72per complete revolution of the secondary ratchet wheel resulting in an arcuate movement of about 62of the indicator wheel per year (86% of 72= 62). As the indicator wheel blue segment 101 intercepts an arc of 62, only the blue segment will be visible through the viewing window during the first year of operation of the appliance. It will be noteclin FIG. 1 that the window 106 preferably intercepts an arcuate opening or segment of about l0in the cover. During the next warranty period, which in the form shown is four years in length, the indicator wheel will move through an angle of about 248. As the green segment covers an arc of 248, only the green color will be visible through the viewing window 106 during the second throughthe fifth year of operation of the appliance. i V v After the completion of five years of service the pinion gear will advanc the indicator wheel 94 into the final 50segment of its movement until only the red portion 103 of its surface will be visible. At this point the indicator wheel teeth 112 are interrupted at 114 to prevent further rotation of the indicator wheel so that the red color of segment 103 will be permanently visible through the window 106 to show that the appliance is now out of warranty.

The partial schematic wiring diagram of FIG. 7 also includes four

female receptacles

121, 122, 123 and 124 located on a plug in the machinery compartment of the refrigerator for receiving the four male 31, 32, 33 and 34 respectively. The FIG. 7 schematic also includes a cold control 126, a starting relay 128 and a motorcompressor unit 130.

While the embodiment of the present invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted.

I claim:

1. A refrigerator defrost timer switch for indicating and recording the elapsed time during which a refrigerator has been in operation comprising. a housing enclosing a plurality of switch contact means, switch cam means rotatably mounted in said housing, timer motive means for driving said switch cam means, said switch cam means coacting with said switch contact means for causing electrical contact between the contact means to initiate a defrost cycle of the refrigerator, a plurality of ratchet wheels coaxially mounted in said housing for independent rotation on a common axis, pawl means operated by said switch cam means for engagement with the primary one of said plurality of ratchet wheels whereby partial rotation is imparted thereto in a toothby-tooth manner upon each defrost cycle of said switch cam means, driving means interconnecting said plurality of ratchet wheels whereby a final secondary ratchet wheel is advanced one tooth segment upon a predetermined rotation of said primary ratchet wheel, gear means on said secondary ratchet wheel meshing with an indicator gear wheel revolvably supported on said housing, said indicator wheel having a plurality of arcuate segments positioned on one surface thereof, said indicator wheel being rotated by said gear means through a succession of said arcuate segments upon the completion of a predetermined number of defrost cycles of said defrost timer, each of said arcuate segments having a coded marking thereon associated with different elapsed time intervals of the refrigerator warranty, window means on said housing for viewing the sequential advancement of said segments to provide a visual indication of the elapsed time of the refrigerator warranty, and means for stopping the rotation of said indicator wheel upon the final coded segment being rotated into view through said window means indicating and recording the expiration of the refrigerator warranty periods.

2. A refrigerator defrost timer switch for indicating and recording the elapsed time during which a refrigerator has been in operation comprising, a housing enclosing a plurality of switch contact means, spiral cam means rotatably mounted in said housing, timer motive means for driving said spiral cam means, said spiral cam means coacting with said switch contact means for causing sequential electrical contact between the contact means to initiate a defrost cycle of the refrigerator, dual primary and secondary ratchet wheels coaxially mounted in said housing for independent rotation on a common axis, pawl means operated by said spiral cam means for engagement with said primary ratchet wheel whereby partial rotation is imparted thereto in a tooth-by-tooth manner upon each defrost cycle of said spiral cam means, an eccentric cam on said primary ratchet wheel and a cam followerv intermediate said ratchet wheels mounted on said eccentric cam drivingly interconnecting said ratchet wheels whereby the secondary ratchet wheel is advanced one tooth segment upon a predetermined rotation of said primary ratchet wheel, gear means on said secondary ratchet wheel meshing with an indicator gear wheel revolvably supported on said housing, said indicator wheel having a plurality of arcuate segments positioned on one surface thereof, said indicator wheel being rotated by said gear means through a succession of said arcuate segments upon the completion of a predetermined number of defrost cycles of said defrost timer, each of said arcuate segments having a coded marking thereon associated with different time intervals of the refrigerator warranty, window means on said housing for viewing the sequential advancement of said segments to provide a visual indication of the elapsed time of the refrigeration warranty, and means for stopping the rotation of said indicator wheel upon the final coded segment being rotated into view through said window means indicating and recording the expiration of the refrigerator warranty periods.

3. In a refrigerator defrost control system including a compressor element, a defrosting heater, a cold control thermostat, and a timer operated electrical switch means for providing a defrost cycle, said switch means including a housing enclosing a switch cam driven by said timer, said switch including a first contact blade operatively connected to said compressor element, a second contact blade operatively connected to said heater, a third contact blade operatively connected to a power supply means and biased toward contact with said first contact means, said switch cam coacting with the contact means for causing contact between said third contact means and said second contact means; the improvement comprising primary and secondary ratchet wheels having identically pitched teeth mounted for independent rotation on a common spindle extending vertically from the base wall of said housing, an actuating arm on said first contact blade, said actuating arm having a pawl thereon disposed in peripheral engagement with said primary ratchet wheel teeth to advance said primary wheel in a counterclockwise direction one tooth upon each complete rotation of said switch cam, said primary wheel having a hub cam fixed on its inner surface eccentric from the common axis of rotation of said ratchet wheels, a cam follower intermediate said lower and upper wheels mounted in contact with said hub cam, an operating bar positioned on said cam follower for engagement with the teeth of said secondary wheel, said cam follower bar being operable by said eccentric hub cam such that upon each complete rotation of said primary ratchet wheel said secondary ratchet wheel is advanced in a counterclockwise direction one tooth by said operating bar, a leaf spring mounted in said housing biasing said cam follower bar into engagement with the teeth of said secondary ratchet wheel, spring finger means on said housing preventing counterclockwise rotation of said primary and secondary ratchet wheels, a pinion gear fixed concentrically on the outer surface of said secondary ratchet wheel meshing with peripheral teeth of an indicator gear wheel, said indicator wheel revolvfrigerator has elapsed.

ably supported on said housing for rotation in a clock wise direction, said indicator wheel having a first radial color segment visible through window means in said housing indicating the appliance is operating during the first period of its warranty, a second radial color segment being rotated into view by said pinion gear indicating that a second period of warranty is in effect, and a third radial color segment on said indicator wheel being rotated into view after a final rotational advance of said indicator wheel operative to be permanently visible indicating that the total warranty time period has expired.

- 4. In a refrigerator defrost control system including a compressor element, a defrosting heater, a cold control thermostat, and a timer operated electrical switch for providing a defrost cycle, said switch including a housing having one open side closed by a cover member for enclosing a spiral cam driven by said timer, said switch housing including a first blade contact operatively connected to said compressor element, a second blade contact operatively connected to said heater, a third blade contact operatively connected to a power supply means and biased toward contact with said first blade contact, said spiral cam coacting with said blade contacts for causing contact between said third blade contact and said second blade contact; the improvement comprisinsg lower and upper ratchet wheels having identically pitched teeth, said ratchet wheels mounted for independent rotation on a common spindle extending vertically from the base wall of said housing, an actuating arm extending from said first blade contact, said actuating arm having a pawl thereon disposed in peripheral engagement with said lower ratchet wheel teeth to move said lower wheel in a counter clockwise direction one tooth by means of said first blade contact dropping off a notch of said spiral earn upon each 360rotation thereof, said lower wheel ha'v ing a hub cam fixed on its inner surface eccentric from the common spindle axis of rotation of said ratchet wheels, a cam follower intermediate said lower and upper wheels having an elongated aperture mounted in contact with said hub cam, an operating bar positioned on said cam follower for engagement with the teeth of said upper wheel, spring means connected to said ca'm follower radially biasing said bar into peripheral engagement with the teeth of said upper ratchet wheel, said bar being operable by said eccentric cam such that upon each complete rotation of said primary ratchet wheel said secondary ratchet wheel is advanced in a counterclockwise direction one tooth by said operating bar, a pinion gear fixed concentrically on the outer surface of said secondary ratchet wheel meshing with peripheral teeth of an indicator wheel, said indicator wheel rotatably mounted on the underside of said cover for clockwise movement by said pinion gear, a window in said cover for viewing a portion of said indicator wheel upper surface, said indicator wheel having a plurality of pie-shaped color segments thereon, said first radial color segment being partially visible through said window indicating the appliance is operating within the first time period of its warranty, said indicator wheel having a second radial color segment being rotated into view through said window by said pinion gear after a predetermined further rotational movement of said ratchet wheels indicating that a second period warranty time is in effect, and said indicator wheel having a third radial color segmentbeing rotated into view through said window by said pinion gear after a final rotational movement of said indicator wheel so as to be permanently visible through, said window providing visual indication that the total warranty time period of said re-

Claims

1. A refrigerator defrost timer switch for indicating And recording the elapsed time during which a refrigerator has been in operation comprising, a housing enclosing a plurality of switch contact means, switch cam means rotatably mounted in said housing, timer motive means for driving said switch cam means, said switch cam means coacting with said switch contact means for causing electrical contact between the contact means to initiate a defrost cycle of the refrigerator, a plurality of ratchet wheels coaxially mounted in said housing for independent rotation on a common axis, pawl means operated by said switch cam means for engagement with the primary one of said plurality of ratchet wheels whereby partial rotation is imparted thereto in a toothby-tooth manner upon each defrost cycle of said switch cam means, driving means interconnecting said plurality of ratchet wheels whereby a final secondary ratchet wheel is advanced one tooth segment upon a predetermined rotation of said primary ratchet wheel, gear means on said secondary ratchet wheel meshing with an indicator gear wheel revolvably supported on said housing, said indicator wheel having a plurality of arcuate segments positioned on one surface thereof, said indicator wheel being rotated by said gear means through a succession of said arcuate segments upon the completion of a predetermined number of defrost cycles of said defrost timer, each of said arcuate segments having a coded marking thereon associated with different elapsed time intervals of the refrigerator warranty, window means on said housing for viewing the sequential advancement of said segments to provide a visual indication of the elapsed time of the refrigerator warranty, and means for stopping the rotation of said indicator wheel upon the final coded segment being rotated into view through said window means indicating and recording the expiration of the refrigerator warranty periods.

2. A refrigerator defrost timer switch for indicating and recording the elapsed time during which a refrigerator has been in operation comprising, a housing enclosing a plurality of switch contact means, spiral cam means rotatably mounted in said housing, timer motive means for driving said spiral cam means, said spiral cam means coacting with said switch contact means for causing sequential electrical contact between the contact means to initiate a defrost cycle of the refrigerator, dual primary and secondary ratchet wheels coaxially mounted in said housing for independent rotation on a common axis, pawl means operated by said spiral cam means for engagement with said primary ratchet wheel whereby partial rotation is imparted thereto in a tooth-by-tooth manner upon each defrost cycle of said spiral cam means, an eccentric cam on said primary ratchet wheel and a cam follower intermediate said ratchet wheels mounted on said eccentric cam drivingly interconnecting said ratchet wheels whereby the secondary ratchet wheel is advanced one tooth segment upon a predetermined rotation of said primary ratchet wheel, gear means on said secondary ratchet wheel meshing with an indicator gear wheel revolvably supported on said housing, said indicator wheel having a plurality of arcuate segments positioned on one surface thereof, said indicator wheel being rotated by said gear means through a succession of said arcuate segments upon the completion of a predetermined number of defrost cycles of said defrost timer, each of said arcuate segments having a coded marking thereon associated with different time intervals of the refrigerator warranty, window means on said housing for viewing the sequential advancement of said segments to provide a visual indication of the elapsed time of the refrigeration warranty, and means for stopping the rotation of said indicator wheel upon the final coded segment being rotated into view through said window means indicating and recording the expiration of the refrigerator warranty periods.

3. In a refrigerator defrost control system including a compressor element, a defrosting heater, a cold control thermostat, and a timer operated electrical switch means for providing a defrost cycle, said switch means including a housing enclosing a switch cam driven by said timer, said switch including a first contact blade operatively connected to said compressor element, a second contact blade operatively connected to said heater, a third contact blade operatively connected to a power supply means and biased toward contact with said first contact means, said switch cam coacting with the contact means for causing contact between said third contact means and said second contact means; the improvement comprising primary and secondary ratchet wheels having identically pitched teeth mounted for independent rotation on a common spindle extending vertically from the base wall of said housing, an actuating arm on said first contact blade, said actuating arm having a pawl thereon disposed in peripheral engagement with said primary ratchet wheel teeth to advance said primary wheel in a counterclockwise direction one tooth upon each complete rotation of said switch cam, said primary wheel having a hub cam fixed on its inner surface eccentric from the common axis of rotation of said ratchet wheels, a cam follower intermediate said lower and upper wheels mounted in contact with said hub cam, an operating bar positioned on said cam follower for engagement with the teeth of said secondary wheel, said cam follower bar being operable by said eccentric hub cam such that upon each complete rotation of said primary ratchet wheel said secondary ratchet wheel is advanced in a counterclockwise direction one tooth by said operating bar, a leaf spring mounted in said housing biasing said cam follower bar into engagement with the teeth of said secondary ratchet wheel, spring finger means on said housing preventing counterclockwise rotation of said primary and secondary ratchet wheels, a pinion gear fixed concentrically on the outer surface of said secondary ratchet wheel meshing with peripheral teeth of an indicator gear wheel, said indicator wheel revolvably supported on said housing for rotation in a clockwise direction, said indicator wheel having a first radial color segment visible through window means in said housing indicating the appliance is operating during the first period of its warranty, a second radial color segment being rotated into view by said pinion gear indicating that a second period of warranty is in effect, and a third radial color segment on said indicator wheel being rotated into view after a final rotational advance of said indicator wheel operative to be permanently visible indicating that the total warranty time period has expired.

4. In a refrigerator defrost control system including a compressor element, a defrosting heater, a cold control thermostat, and a timer operated electrical switch for providing a defrost cycle, said switch including a housing having one open side closed by a cover member for enclosing a spiral cam driven by said timer, said switch housing including a first blade contact operatively connected to said compressor element, a second blade contact operatively connected to said heater, a third blade contact operatively connected to a power supply means and biased toward contact with said first blade contact, said spiral cam coacting with said blade contacts for causing contact between said third blade contact and said second blade contact; the improvement comprisinsg lower and upper ratchet wheels having identically pitched teeth, said ratchet wheels mounted for independent rotation on a common spindle extending vertically from the base wall of said housing, an actuating arm extending from said first blade contact, said actuating arm having a pawl thereon disposed in peripheral engagement with said lower ratchet wheel teeth to move said lower wheel in a counterclockwise direction one tooth by means of said first blade contact dropping off a notch of said spiral cam upon each 360*rotation thereof, said lower wheel having a hub cam fixed on its inner surface eccentriC from the common spindle axis of rotation of said ratchet wheels, a cam follower intermediate said lower and upper wheels having an elongated aperture mounted in contact with said hub cam, an operating bar positioned on said cam follower for engagement with the teeth of said upper wheel, spring means connected to said cam follower radially biasing said bar into peripheral engagement with the teeth of said upper ratchet wheel, said bar being operable by said eccentric cam such that upon each complete rotation of said primary ratchet wheel said secondary ratchet wheel is advanced in a counterclockwise direction one tooth by said operating bar, a pinion gear fixed concentrically on the outer surface of said secondary ratchet wheel meshing with peripheral teeth of an indicator wheel, said indicator wheel rotatably mounted on the underside of said cover for clockwise movement by said pinion gear, a window in said cover for viewing a portion of said indicator wheel upper surface, said indicator wheel having a plurality of pie-shaped color segments thereon, said first radial color segment being partially visible through said window indicating the appliance is operating within the first time period of its warranty, said indicator wheel having a second radial color segment being rotated into view through said window by said pinion gear after a predetermined further rotational movement of said ratchet wheels indicating that a second period warranty time is in effect, and said indicator wheel having a third radial color segment being rotated into view through said window by said pinion gear after a final rotational movement of said indicator wheel so as to be permanently visible through said window providing visual indication that the total warranty time period of said refrigerator has elapsed.