US3575561A - Defrost control system device with improved lever operating means - Google Patents

Defrost control system device with improved lever operating means Download PDF

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Publication number
US3575561A
US3575561A US779129A US3575561DA US3575561A US 3575561 A US3575561 A US 3575561A US 779129 A US779129 A US 779129A US 3575561D A US3575561D A US 3575561DA US 3575561 A US3575561 A US 3575561A
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United States
Prior art keywords
lever
levers
cam means
set forth
cam
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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US779129A
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English (en)
Inventor
Robert L Wooding
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Robertshaw Controls Co
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Robertshaw Controls Co
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Publication date
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H3/00—Mechanisms for operating contacts
    • H01H3/004—Mechanisms for operating contacts for operating contacts periodically
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T74/00—Machine element or mechanism
    • Y10T74/11—Tripping mechanism
    • Y10T74/114—Retarded
    • Y10T74/116—Clock train

Definitions

  • the cam means maintains the one lever in one position thereof until the defrost cycle is to be initiated whereby the one lever moves to another position thereof and remains in that position until the cam means causes the other lever means to engage against the one lever and move the same back to its one operating position, the cam means thereafter causing the other lever to move out of engagement with the one lever while maintaining the one lever in its one position thereof.
  • one embodiment of this invention provides a control device having a pair of movable levers controlled by a timer operated cam means wherein one of the levers is operatively associated with the electrical switch means of the control device.
  • a tension spring means is respectively interconnected to the two levers to tend to maintain the same in operativeengagement with the cam means, the cam means being disposed between the levers and being so constructed and arranged that the same maintains the one lever in one operating position thereof for a predetermined period of time and, thereafter, causes the one lever to move to another operating position thereof for another predetermined period of time after the lapse of which the cam means causes the other lever to engage against the first lever and move the first lever back to its first operating position. Subsequently, the cam means moves the other lever away from the first lever while maintaining the first lever in its one operating position until it is time to again initiate a defrost cycle wherein the cam means again causes movement of the first lever to its other operating position.
  • Another object of this invention is to provide an improved control device having one or more of the novel features set forth above or hereinafter shown or described.
  • FIG. I is a perspective view of the improved control device of this invention.
  • FIG. 2 is an enlarged cross-sectional view taken on line 22 of FIG. 1
  • FIG. 3 is a cross-sectional view taken on line 3-3 of FIG. 2 and illustrates the control device in one of its operating positions.
  • FIG. 4 is a view similar to FIG. 3 and illustrates the control device in another operating position thereof.
  • FIG. 5 is a view similar to FIG. 3 and illustrates the control device being moved back to the operating position of FIG. 3.
  • FIG. 6 is a side view of part of the electrical switch means of the control device of FIG. 1.
  • FIG. 7 is a perspective view of one of the operating levers of the control device of FIG. 1.
  • FIG. 8 illustrates schematically one control system of this invention.
  • the improved control device of this invention is generally indicated by the reference numeral 10 and comprises a housing means 11 having a chamber 12 therein receiving and supporting a conventional timer motor means 13 therein, the timer motor 13 having an output shaft 14 carrying a pinion gear 15 disposed in meshing relation with a larger gear 16 interconnected by suitable friction clutch means to a shaft means 17 rotatably mounted to the housing means 11 by having its opposed ends respectively received in opening means 18 and 19 of a removable end wall means 20 of the housing means 11 and a support means 21 that is secured in spaced relation to the end wall means 20.
  • the friction clutch means (not shown) that interconnects the gear 16 to the shaft 17 is so constructed and arranged that movement of the pinion gear 15 by the timer motor 13 causes simultaneous movement of the shaft means 17 through the gear 16 and friction clutch means so that there is no slippage between the gear means 16 and the shaft means 17 except when the shaft means 17 is turned manually to position the shaft means 17 in a new rotational position relative to the gear 16 as will be apparent hereinafter whereby such manual setting of the shaft 17 relative to the gear 16 will not adversely affect the timer motor 13.
  • a cam means 22 is secured to the shaft means 17 to rotate in unison with the shaft means 17, the cam means 22 comprising a first cam member 23 having a drop off 24, FIG. 3, in its outer peripheral cam surface 25 and a second cam member 26 having two drop off points 27 and 28 in its outer peripheral cam surface 29. While the cam members 23 and 26 are illustrated and hereinafter described as being fixed to the shaft 17 in the relationship illustrated in FIG. 3, it is to be understood that the cam means 23 and 26 can be made adjustable on the shaft means 17 so that an operator or the like can adjust the relative positions of the cam means 23 and 26 to a desired timing sequence condition as will be apparent hereinafter.
  • the frame or support member 21 carries a pair of outwardly directed pairs or posts 30 and 31 at the opposed ends 32 and 33 thereof that secure the support member 21 in spaced relation to the end wall means 20, the post means 30 and 31 respectively having annular recesses 34 and 35 therein to respectively pivotally mount a pair of levers 36 and 37 in the housing means 11.
  • the lever 36 has a U-shaped yoke 38 surrounding the post 30 and being received in the recess 34 thereof, the lever 36 being provided with a cam follower portion or tongue 39 adapted to operatively engage and follow the cam contour surface 25 of the cam member 23.
  • the lever 37 has a U-shaped yoke portion 40 surrounding the post 31 and being received in the annular groove 35 thereof, the lever 37 having a cam follower or tongue portion 41 adapted to operatively engage and follow the cam contour or surface 29 of the cam 26.
  • a tension spring 42 has its opposed ends 43 and 44 respectively interconnected to the levers 36 and 37 to continuously tend to pull the levers 36 and 37 toward each other so that the cam follower portions 39 and 41 thereof are respectively drawn toward their respective earns 23 and 26 for a purpose hereinafter described.
  • the arrangement of the spring '42 relative to the levers 36 and 37 as well as relative to the posts 30 and 31 causes the spring 42 to hold the levers 36 and 37 against the posts 30 and 31 so that the levers 36 and 37 will respectively pivot about the posts 30 and 31 as will be apparent hereinafter.
  • the lever 36 has an outwardly directed arcuate tongue 45 adapted to engage against an upwardly directed fiat tang 46 formed on the lever 37 when the cam means 22 is disposed in the position illustrated in FIG. 5 for a purpose hereinafter described.
  • An electrical switch means 47 is carried by the housing means 11 and comprises a pair of spaced stationary electrical contacts 48 and 49 respectively carried by terminals 50 and 51 which are supported by an end wall 20A of the housing 11 and project outwardly therefrom as illustrated in FIG. 1 to be interconnected to suitable lead means.
  • Another terminal 52 is also carried by the housing means 11 to project out of the end wall 20A as illustrated in FIG. 1, the terminal 52 as illustrated in FIG. 2 and 6 additionally carrying a flexible conductive switch blade 53 having one end 54 secured to the terminal 52 and an opposed free end 55 carrying contact means 56 on the opposed sides 57 and 58 thereof.
  • the lever 37 has a retainer 59 secured thereto by having a rectangular portion 60 thereof passed through a like opening 61 in the lever 37 and being suitably staked thereto, the retainer 59 having a pair of spaced abutments 62 and 63 projecting rearwardly therefrom with the abutments 62 and 63 respectively having facing surfaces 64 and 65 that are convex in cross-sectional configuration and defining a spacing 66 therebetween.
  • the retainer is formed of suitable electrically insulating material, such as plastic or the like molded or otherwise formed in the configuration illustrated in the drawings.
  • the switch 47, timer motor 13 and housing means 11 can be assembled together as one subassembly and the levers 36 and 37, shaft 17, cam mearis 22, gear 16 and spring 42 can be assembled together with the end wall 20 and frame member 21 to form another subassembly that can be inserted as a unit into the chamber 12 of the housing means 11 in such a manner that the gear 16 will mesh with the gear and the retainer 59 will receive the switch blade 53 in the spacing 66 between the abutments 62 and 63 thereof, the end wall being subsequently secured in place to the housing means 11 by suitable fastening means to complete the control device 10.
  • control device 10 of this invention can be utilized to control any desired system
  • one system of this invention is generally indicated by the reference numeral 67 in FIG. 8 wherein a power source lead L, is interconnected by a lead 68 to the terminal 52.
  • the other power source lead L is interconnected by a lead 69 to one side 70 of a refrigerator compressor means 71 while the other side 72 thereof is interconnected by a lead 73 to the terminal 51 that carries the contact 49 of the electrical switch 47.
  • the lead 69 is also interconnected by a lead 74 to one side 75 of an electrical heater means 76 that can be utilized for defrosting the evaporator (not shown) of the refrigerator system 67 when the heater means 76 is energized, the other side 77 of the heater means 76 being interconnected by a lead 78 to the terminal 50 of the control device 10 that carries the contact 48 of the electrical switch means 47.
  • control device 10 of this invention as utilized in control system 67 of FIG. 8 will now be described.
  • the timer motor 13 of the control device 10 interconnected to the power source leads L, and L, by leads 79 and 80 as illustrated in FIG. 1, the timer motor 13 will be continuously running to rotate the shaft 17 and, thus, the cam means 22 in a counterclockwise direction as illustrated by the arrows in FIGS. 3-5 whereby in the typical system 67 of this invention, the gear ratio 15,16 can be so constructed and arranged that the shaft 17 and, thus, the cam means 22 will make one complete revolution every 6 hours so that a defrosting cycle will occur once in every 6 hour period.
  • the other lever 36 is still spaced from the lever 37 because the cam follower 39 of the lever 36 is riding on the high part of the cam surface 25 of the cam 23 though closely adjacent the drop off point 24 thereof.
  • the defrost cycle continues for a predetermined period of time as illustrated in FIG. 4 until the cam means 22 further rotates in a counterclockwise direction so that the cam follower 39 of the lever 36 falls off the drop off point 24 of the cam member 23 in the manner illustrated in FIG. 5 whereby the stored energy in the tension spring 42 pulls the lever 36 toward the lever 37 and the tongue 45 of the lever 36 engages the tang 46 of the lever 37 as illustrated in FIG. 5.
  • the force of the spring 42 is such that when the tongue 45 of the lever 36 engages the tang 46 of the lever 37, the spring 42 causes the lever 36 to pivot the lever 36 in a counterclockwise direction about the pivot post 31 to move the switch blade 53 to the right and cause the contact means 56 to break electrical contact with the fixed contact 48 and be placed back into electrical contact with the fixed contact 49 as illustrated in FIG. 5 whereby the operation of the defrost cycle is terminated and the compressor 71 is again energized to perform its normal function for another cycle of rotation of the cam means 22.
  • the drop off points 27 and 24 of the cam means 26 and 23 can be so arranged relative to each other that the length of the defrost cycle can be any desired period, such as 14 minutes during any 6 hour period of operation of the control device Accordingly, it can be seen that when it is desired to first install the control device 10 of this invention in the control system 67 of FIG.
  • the shaft means 17 of the control device 10 can be initially turned to a position wherein the cam follower 39 of the lever 37 has just fallen off the drop off point 24 of the cam 23 to permit the contact 56 to be engaged against the contact 49 so that the first defrost cycle caused by the control device 10 in the system 67 will occur toward the end of one complete revolution of the shaft 17 and will occur thereafter toward the end of each succeeding complete revolution of the shaft 17 by the timer motor 13.
  • the friction clutch means interconnecting the gear 16 to the shaft 17 permits such initial lmanual adjusting of the shaft 17 relative to the timer motor 13 without adversely affecting the motor 13 during such manual setting of the shaft 17.
  • this invention provides not only an improved defrost control system, but also this invention provides an improved control device for such a system or the like.
  • a defrost control system having a timer operated electrical switch means for providing a defrost cycle of said system, the improvement comprising cam means driven by said timer, a pair of movable levers, one of said levers being operatively interconnected with said switch means for controlling the same in relation to the position of said one lever, and means operatively interconnected to said levers tending to maintain said levers in engagement with said cam means, said cam means being so constructed and arranged that said cam means by its engagement with said one lever being adapted to maintain said one lever in one position thereof for a first predetermined period of time and then cause movement of said one lever to another position thereof for a second predetermined period of time for said switch means to provide said defrost cycle, said cam means thereafter being adapted tocause movement of the other of said levers into engagement with said one lever to move said one lever back to said one position thereof after the lapse of said second predetermined period of time by its engagement with said other lever.
  • levers are pivotally mounted at diametrically opposed ends thereof.
  • said switch means comprises a switch blade, said one lever having a pair of spaced abutments receiving said switch blade therebetween to interconnect said switch blade to said one lever.
  • a control device comprising a housing means, an electrical switch means carried by said housing means, a pair of movable levers carried by said housing means, one of said levers being operatively interconnected with said switch means for controlling the same in relation to the position of said one lever relative to said housing means, movable cam means carried by said housing means, and means carried by said housing means and being operatively interconnected with said levers for tending to maintain said levers in engagement with said cam means during movement of said cam means, said cam means being so constructed and arranged that said cam means be its engagement with said one lever being adapted to maintain said one lever in one position thereof during a first segment of movement of said cam means in one direction thereof and to then cause movement of said one lever to another position thereof during a second segment of movement of said cam means in said one direction, said cam means thereafter being adapted to cause movement of the other of said levers into engagement with said one lever to move said one lever back to said one position thereof during a third segment of movement of said cam means in said one direction thereof by its engagement with said other lever.
  • a control device as set forth in claim 11 wherein said means for tending to maintain said levers in operative engagement with said cam means comprises a single tension spring.
  • said switch means comprises a switch blade, said one lever having a pair of spaced abutments receiving said switch blade therebetween to interconnect said switch blade to said one lever.

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  • Defrosting Systems (AREA)
  • Thermally Actuated Switches (AREA)
US779129A 1968-11-26 1968-11-26 Defrost control system device with improved lever operating means Expired - Lifetime US3575561A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US77912968A 1968-11-26 1968-11-26

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US3575561A true US3575561A (en) 1971-04-20

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US779129A Expired - Lifetime US3575561A (en) 1968-11-26 1968-11-26 Defrost control system device with improved lever operating means

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US (1) US3575561A (enExample)
JP (1) JPS4923928B1 (enExample)
DE (1) DE1959133A1 (enExample)
FR (1) FR2024275A1 (enExample)
GB (1) GB1290348A (enExample)
SE (1) SE355240B (enExample)

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1951028A (en) * 1931-11-24 1934-03-13 Lux Clock Mfg Company Electric range time switch
US2060991A (en) * 1933-05-12 1936-11-17 Sangamo Electric Co Astronomic dial for time switches
US2430286A (en) * 1946-02-16 1947-11-04 Dean F Flegel Automatic electric time switch
US2788850A (en) * 1952-08-19 1957-04-16 Ad Schulthess & Co A G Control for automatic washing machines
US2922900A (en) * 1954-03-01 1960-01-26 Cincinnati Time Recorder Co Program timer
US2949017A (en) * 1957-06-07 1960-08-16 Tyler Refrigeration Corp Time temperature defrost control
US3033950A (en) * 1959-04-17 1962-05-08 Reliance Time Controls Inc Electrical timer switch control
US3304001A (en) * 1965-07-21 1967-02-14 Robertshaw Controls Co Timer adjusted temperature controlling means for ovens and the like
US3399541A (en) * 1966-04-25 1968-09-03 Robert H. Thorner Defroster control

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1951028A (en) * 1931-11-24 1934-03-13 Lux Clock Mfg Company Electric range time switch
US2060991A (en) * 1933-05-12 1936-11-17 Sangamo Electric Co Astronomic dial for time switches
US2430286A (en) * 1946-02-16 1947-11-04 Dean F Flegel Automatic electric time switch
US2788850A (en) * 1952-08-19 1957-04-16 Ad Schulthess & Co A G Control for automatic washing machines
US2922900A (en) * 1954-03-01 1960-01-26 Cincinnati Time Recorder Co Program timer
US2949017A (en) * 1957-06-07 1960-08-16 Tyler Refrigeration Corp Time temperature defrost control
US3033950A (en) * 1959-04-17 1962-05-08 Reliance Time Controls Inc Electrical timer switch control
US3304001A (en) * 1965-07-21 1967-02-14 Robertshaw Controls Co Timer adjusted temperature controlling means for ovens and the like
US3399541A (en) * 1966-04-25 1968-09-03 Robert H. Thorner Defroster control

Also Published As

Publication number Publication date
DE1959133A1 (de) 1970-07-30
GB1290348A (enExample) 1972-09-27
FR2024275A1 (enExample) 1970-08-28
JPS4923928B1 (enExample) 1974-06-19
SE355240B (enExample) 1973-04-09

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