US2536741A

US2536741A - Defrosting timer

Info

Publication number: US2536741A
Application number: US121619A
Authority: US
Inventors: Richard A Haigh
Original assignee: Automatic Controls Corp
Current assignee: Automatic Controls Corp
Priority date: 1949-10-15
Filing date: 1949-10-15
Publication date: 1951-01-02
Anticipated expiration: 1968-01-02

Description

Jan. 2, 1951 HAIGH 2,536,741

DEFROSTING TIMER Filed Oct. 15, 1949 A TTWRNEYS Patented Jan. 2, 1951 UNITED-- PATENT OFF ICE.

DEFROSTING' TIMERv Richard-A. Haigh; Brighton, Mich., assignor to- Automatic; Controls Gorporation, Ann Arbor, Michv, .a' corp oration-of Michigan Application ct'ober15, 1949; SerialNo. 121,619

I Claims; 1

This invention relates to improvements in defrosting timers; thatis to say clock controlled mitting the adjustmentof the twenty-four hour wheel of the unit to the time of day when the unit is installed independently of the angular position of the clOckshaft;

Still another objectis the provision of means accessible from the exterior of" the: unit casing for varying the length of the period duringwhich defrosting takes place.

Other objects and features of novelty will appear'asI proceed with the description of that embodiment of the invention-which, for the pur poses of the present application, I have illustrated in the accompanying drawing; in which Fig. 1 is a plan view of the unit looking toward the cover of inverted cup shape, it being understood that the face of the cover stands ina: vertical plane when the unit is attached to awall receptacle.

Fig. 2 is a plan view partially insectiorlalong theline 2--2'of Fig.3;

Fig; 3 is a View of the unit'partiallydn eleva tion and partially in section along. theli'ne33 of Fig. 1. v Fig. 4. is a large scale fragmental' viewwith the cover removed and illustrating" the Geneva. motion driving means from. the clock shaft to the twenty-four hour: wheel; a

Fig. 5 is: a, similar view. with the partsv in. the open switch or defrosting position.

Fig. 6 is a. detail view illustrating thezmeans for disconnecting the Geneva motion. drive-when the twenty-four. hour wheel: is being: advanced.- manually in the operation of. setting" the unit in:

accordance with: the. time of day.

Fig- 7 is a detail sectional view' taken sub stantially on the line 1-1 of Fig- 2;.

Fig. 8 is a large scale detail sectional view of the twenty-four hour wheelv and; associated parts.

Fig. 9 is an inverted plan view'of the rotating handle-pointed corresponding to thehour hand of a twenty-four hour clock,.and;

Fig. 10 is an: inverted plan view of the: arm. whichv moves with the pointed and; adjustable relatively thereto for. varying the defrosting period.

The defrostingsunit-of the present; invention; comprises a flatbase i5. upon: which theworking;

parts of the. unit. are mounted and a cover; lzfi.

shaped like an: inverted. cup and secured. to. the:

base by means of a plurality of screws i! which extend through openings in the base and are threaded into holes l8- formed in bosses project ing inwardly from the cover walls. The two casing parts arepreferabiy constructed of molded plastic.

A pair of metal prongs l9 extend through the base IS-near the perimeter thereof, being preferably fixed in the base during the molding opera-'- tion. These prongs have lateral oiiset portions which engage a small ledge 2| on the base. From the upper ends-of the oiTset portions fingers 22-" project inwardly and are electrically connected tothe-ends of the coil 23 of asynchronous motor. The coil is wound upon a laminated core 2d which is securedto the base [5 by bolts or screws, thus holding the coil 23-firmly'in place.

One of the cover bosses is provided with a pair of slots 25: which. snugly receive the offsets 23' of the prongs when the cover is mounted in place. These. slots-may be tapered with the point of? the: taper uppermost so that the offsets are readily received within the slots when the cover islputinplace; Because of this construction the prongs have a. firm bearing notonly in the base is but: alsoin the cover portion of the casing at av point. spaced. from the first named bearing. Hence the-mechanical connection of the. prongstothe casing isv especially strong and rigid, which is an. important. consideration. since. the. prongs, in addition tomaking the necessary electrical connection of the unit with: thehouse wires, serve as: the support: for the. unit. When the unit is. in. use. the prongs extend into a. wall socket. or. receptacle, bringing the base l5 into a vertical plane against, the receptacle or wall.

The. internal construction. of the unit comprises bracket. means for supporting the various working parts. As'illustrated herein thisbracket means, which is omitted from Figs. 4 and 5 for. the: sake of clearness, includes an inverted sheet metal U- member 2'1. with an. extension 23. to which. is: attached av socket 2-3, that projects through a slot. 38 in the cover Hi. and is intended toreceive the'plug: on; the electric conductor for the refrigeraton. Bracket member 2'1 supports the upper'bearingsl. for theshaft 32. of the clock 33. Bracket; member 27 also has a pair of arms. and 35: which support a strip. of insulating material 36 upon. which are carried. the switch anditsaact'uating lever presently to be described.

Thev bracket memberv 2?; has attached thereto a: second: upwardly extending inverted U member 31: of: sheet metal, the function of which is I to support the-upper bearing 38 for the twentyfour hour wheel 39. This wheel has a downwardly projecting shaft ii which is journaled in the bracket member 21.

Wheel 39 is driven from shaft 32 by a Geneva motion drive of novel form. Wheel 38: is provided with twenty-four peripheral notches 4|, providing twenty-four teeth 42. Surrounding shaft 32 there is a spiral spring 43 of several convolutions which normally grips the shaft closely. At its upper end it has a tangentially projecting part 44 and a downwardly extending,

offset arm 45 which is adapted to extend into the notches 4| of the wheel. Shaft 32 makes one revolution per hour in the counterclockwise direction as viewed in Figs. 4, and 6, and once for each revolution the offset arm 45 enters one of the notches 4| and advances wheel 39 onetwenty-fourth of a revolution clockwise. 46 is a spring detent adapted to engage a notch of the wheel, this detent yielding as the offset arm 45 turns wheel 39, traveling over a tooth 42 and snapping into the next notch 4| of the wheel. Detent 46 therefore holds the wheel against accidental movement and insures its advancement the proper distance as the offset arm 45 of the spring leaves the recess with which it has been in engagement.

The shaft for wheel 39 has a large diameter portion 40 above the Wheel in which there is a diametrical slot 41 for a purpose which will presently appear. Surrounding this shaft 40' there is a sleeve 48 which extends down into a cavity 49 in the wheel. Sleeve 48 has a right angle extension 50 also disposed in cavity 49. At the outer end of this extension there is a downwardly extending pin 5| which projects through a slot 52 in the wheel. A second pin 53 integral with wheel 39 projects downwardly therefrom, these two pins 5| and 53 being disposed at approximately the same radial distance from the axis of the wheel. Sleeve 48 has a pair of oppositely disposed slots 54 extending downwardly from its upper edge. The turning of sleeve 48 through a small angle from the position of Fig. 4 to that of Fig. 5 spaces the pins 5| and 53 further apart. Pin 5| is yieldably held in one or the other of its two operative positions by a small hump 55 at the mid-point of the slot, there being sufficient play in the mounting of the sleeve to permit the pin to ride over this hump when the extension 50 is swung from one position to the other.

Referring now to the switch construction illustrated herein, the insulation strip 38 is formed of stiff material so as to afford a rigid mounting for the switch parts. It supports two

electric terminals

51 and 58 having electrical connections 59 and 60. Terminal 52 is permanently connected with a metallic angle post 6| which has a slot therethrough to receive the long arm of a bell crank lever 62 and form a pivot therefor. When the switch is closed this arm occupies the position illustrated in Fig. 4, in which the extremity of the short arm of the lever bears against the strip 36. A fiat spring metal link 63 has a slot part way of its length which straddles post 6| and the short arm of lever 62. The end of link 63 beyond the slot bears against an indentation in the short arm of the lever. At its opposite end this link carries a contact button 64 and one extremity of a bowed spring 65, the other extremity of which rests in a notch 56 in the post 6 Spring 65 therefore functions to maintain the pivotal connection between conductor 63 and lever 62 by pushing the right hand end of the conductor toward the right as viewed in Figs. 4 and 5, and acts as an electrical conductor between button 64 and post 6|.

As the pin 5| in turning step by step clockwise strikes the long arm of lever 62 and wipes against it the lever is shifted from its Fig. 4 position to that of Fig. 5, which pulls downward flat link 63 below the notch 66. This snaps the link 63 over dead center and causes the contact button 64 to snap down against a stop 61 carried by insulation strip 36, thereby opening the circuit. Before pin 5| passes beyond the end of lever 62, pin 53 comes into contact with the lever and holds it up. When the pins are spaced as in Fig. 5 the period of their contact with the lever is of course longer than when the pins are close together as in Fig. 4. When pin 53 moves out of contact with lever 62 the spring by pulling upon the short arm of the lever swings the latter to the Fig. 4 position, causing the link 63 to shift over to a position above the notch 66 which snaps the contact 64 upwardly into engagement with the terminal 58, again closing the switch.

While I have described more or less in detail a particular type of switch that is suitable for the purposes of the invention, it will be understood that any other switch capable of being actuated by a lever similar to lever 62 may be employed.

When the casing parts l5 and I6 are assembled the shaft 40 and sleeve 48 project through a hole 69 in the casing cover I6. An adjusting arm 70 shown inverted in Fig. 10 is then slipped over the sleeve 48. It is provided with two splines H which enter the slots 54 in the sleeve, thereby locking these two members together against relative rotation. At the outer extremity of arm Ill there is a pin 12 which projects upwardly. When the adjusting arm 10 is in place a handle-pointer 13 is slipped down over the upper extremity of shaft 40', arcuate shaped walls 14 on the handle receiving the shaft and a transverse rib 15 entering the slot 41 at the end of the shaft, thereby locking the pointer to the shaft.

. At its rear end the pointer 13 has an arcuate cutout l6 which receives the pin 12 on the arm 10. At the ends of this cutout the handle-pointer bears indicia indicating the adjustment for the period of defrosting. In this case the indicia are the numbers 3 and 4 indicating defrosting periods 'of three and four hours respectively. In the nor- .mal operation of the device the handle-pointer l3 and the arm 10 move together step by step. On the face of the cover there are printed numbers indicating the time of day in one hour steps both a. m. and p. m.

When one of these units is to be installed the operator turns the handle-pointer l3 clockwise to the time indicated on the face of the cover which is nearest to the then time of day. If at the time this is done the offset arm 45 of spring 43 happens to be out of contact with the wheel 39, as for example in Fig. 5, the rotation of the handle merely causes the spring detent 45 to click from one notch to the next as the wheel is turned. If on the other hand the arm 45 of the spring happens to be in engagement with the wheel, as in Fig. 4, it tends to oppose rotation of the wheel. A slight additional pressure on the wheel by the operator however then unwinds spring 43 slightly, thereby loosening the grip of the spring upon shaft 32 as indicated in Fig. 6 of the drawing. After the grip is thus loosened the spring is read.- ily turned bodily on the shaft 32 without placing any undue strain on the shaft or the clock mech anism connected thereto. It will be observed therefore that when the clock shaft is the driving member the spring tends to wind itself tightly upon the shaft, whereas when the wheel 39 is the driving member, as in setting the handlepointer to the time of day, the spring unwinds and loosens its grip upon the shaft.

Respecting the electric circuits it will" be ob vious that current enters the unit through:v one of the prongs 1-9- and, flows to one of the-connections in the socket 29, asby the: conductor 80, thence through therefrigerator cord to the refri'gerator motor, backto'the other-'connecti'on in socket 2 9, through a conductor 81 to switchcon motion 59, through the switch to connection 60 and thence by a conductor 82 to the other prong IS. The coil 23 of the clock takes its current directly from the prongs l9, as previously described.

The operation of the device it is believed will be clear from the foregoing description of its construction. The

pins

51 and 53 are so disposed with respect to the handle-pointer 13 that during the early morning hours following midnight the switch will be opened for three or four hours, as may be desired, to accomplish the defrosting operation, thereby freeing the refrigerator coils of frost and ice insulation once every twenty-four hours and enabling the refrigerator to operate at maximum efficiency.

It will be apparent that the unit is compact and sturdy, economical to manufacture and assemble, simple to install and not likely to get out of order. The provisions for adjusting it to the time of day and for varying the length of the defrosting period are particularly noteworthy and important.

Having thus described my invention, I claim:

1. In an electrical timing unit, a clock having an hour shaft rotating in a given direction, a second shaft parallel to said clock shaft, a wheel on said second shaft having peripheral notches therein, yieldable means carried by said clock shaft and projecting laterally therefrom for meshing engagement with said notches one at a time and adapted to impart intermittent rotation to said wheel in the reverse direction, a switch, means for actuating said switch comprising a projection turning with said wheel, and means for manually turning said wheel in said reverse direction, said yieldable means being adapted to yield and permit said manual turning in said reverse direction, whereby the angular position of said wheel relative to that of said clock shaft may be manually selected.

2. In an electrical timing unit, a clock having an hour shaft rotating in a given direction, a second shaft parallel to said clock shaft, a wheel on said second shaft having peripheral notches therein, means carried by said clock shaft projecting laterally therefrom for intermittent meshing engagement with said notches one at a time and adapted to impart positive step by step rotation to said wheel in the reverse direction, and means for manually turning said wheel in said reverse direction, said first named means being adapted to yield for permitting rotation of said wheel in said reverse directon, whereby the angular position of said wheel relative to that of said clock shaft may be manually selected.

3. In an electrical timing unit, a clock having a rotating hour shaft, a second shaft parallel to said clock shaft, a wheel on said second shaft having peripheral notches therein, a coil spring surrounding and gripping said clock shaft, one end of said coil spring having an offset arm adapted to enter said notches one after another for imparting intermittent motion to said wheel, a switch adapted to be actuated by said wheel as it moves through a predetermined arc, and manual means for turning said wheel in a direction for causing a notch to bear against said offset arm, unwind said spring, thereby loosening its grip upon said shaft and turning the spring bodily, onisaid shaft, whereby the. angular position of the wheel may be changed while that of the clock shaft remains unaffected.

4. In an" electric timing unit; a clock having an hour. shaft rotatable in" given directiorn a;

secondlshaf-t parallel to saidclock shaft, a: wheel on said second shaft having peripheral notches therein, a coil spring surroundin said clock shaft, one end of said coil spring having an onset arm adapted to enter said notches one after another for imparting intermittent motion to said wheel, the rotation of said clock shaft acting when said arm is in engagement with a notch in said wheel to wind the spring tightly on said shaft for imparting a positive rotational movement to said wheel in a direction reverse to that of said clock shaft, a switch adapted to be actuated by said wheel as it moves through a predetermined arc in said reverse direction, and manual means for turning said wheel in said reverse direction, thereby causing a notch of the wheel to bear against said offset arm, unwind said spring, thereby loosening its grip upon said shaft and turning the spring bodily on said shaft, whereby the angular position of the wheel may be changed while that of the clock shaft remains unaffected.

5. In an electric timing unit, a rotatable wheel, means for imparting intermittent rotation to said wheel, an electric switch, a movable element for actuating said switch, said element being biased toward switch closing position a pair of pins movable with said wheel adapted to engage and shift said movable element once during each revolution of the wheel to open said switch and maintain it open through a given angle of rotation of the wheel, and manual means for moving one of said pins in an arcuate path through a small angle to adjust the spacing of the pins and thereby vary the length of time during which said movable element is maintained in switch opening position.

6. An electric timing unit as defined in claim 5 comprising a sleeve surrounding said second shaft and rotatable thereon through a limited arc, said movable pin being carried by said sleeve, and an arm mounted on said sleeve manually adjustable through said limited arc.

7. In an electric timing unit, a casing, a clock having a rotating hour shaft, a second shaft parallel to said clock shaft projecting through said casing, a wheel keyed to said second shaft within the casing, Geneva motion means for imparting intermittent rotation to said wheel from said clock shaft, an electric switch, a movable element for actuating said switch, a sleeve surrounding said second shaft, a pin carried by said wheel and a pin carried by said sleeve at the same radial distance from said second shaft, said pins being adapted jointly to engage and operate said movable element once during each revolution of the wheel, a handle outside the casing keyed to said shaft, an arm outside the casing keyed to said sleeve and arranged for adjustment through a limited are relative to said handle, and means on the handle holding said arm in adjusted position, whereby the pin on said sleeve may be adjusted relative to the pin on said wheel for regulating the length of time of actuation of said movable element and the consequent actuation of said switch.

RICHARD A. HAIGH.

(References on following page) REFERENCES CITED Number Name Date Johnson Dec. 24, 1935 Number 8 Name Date Sprenger et a1 Apr. 27, 1937 Minneci Oct. 1, 1940 Knight Jan. 28, 1941 Jones May 4, 1943 4 Straitz June 18, 1946 Avery June 28, 1949