US 3552115 A
Description (OCR text may contain errors)
Jan. 5, 1971 LQSERT I 3,552,115
INTERVAL TIMER FOR PROVIDING A FIXED AND LOCKED TIMED CYCLE Filed May 2, 1969 2 Sheets-Sheet I 3e ,54 INVENTOR.
Ger-hard K Lose/'1;
1971 G. K. LOSERT INTERVAL TIMER FOR PROVIDING A FIXED AND LOCKED TIMED CYCLE Filed May 2, 1969 2 Sheeis-Sheet 2 l N V E N TOR. Gerhard ML ass/t ttorwey.
United States Patent 0 3,552,115 INTERVAL TIMER FOR PROVIDING A FIXED AND LOCKED TIMED CYCLE Gerhard K. Losert, Louisville, Ky., assignor to General Electric Company, a corporation of New York Filed May 2, 1969, Ser. No. 821,220 Int. Cl. G04f 1/00 US. Cl. 5822.9 6 Claims ABSTRACT OF THE DISCLOSURE An interval timer for providing a fixed, timed cycle which, when set, cannot be changed in function or timing includes a segmental gear manually rotated in one direction by a setting shaft from an unset position to a set position. The segmental gear has a toothed segment and a mutilated segment equal in angular extent to the angular extent of the manual rotation from the unset to the set position. First and second pinions are provided and continuously mesh with an idler gear. The second pinion is continuously rotated by a driving motor through a suitable gear train, thereby continuously driving the idler gear and the first pinion. Both pinions are freely rotatable in the mutilated segment of the segmental gear when it is in its unset position. Manual rotation of the segmental gear away from its unset position toward its set position moves the toothed segment into alignment with the second pinion. The second pinion is mounted on a spring biased lever for pivotal movement toward and away from the toothed segment, thus permitting the toothed segment to ratchet past the second pinion during manual rotation of the segmental gear from the unset to the set position. Upon reaching the set position, the toothed segment moves into mesh with the first pinion, which is maintained in mesh therewith, thereby inhibiting further manual rotation of the segmental gear in either direction. The segmental gear thereafter is driven in the same one direction toward its unset position, first by both pinions and finally by only the first pinion.
BACKGROUND OF THE INVENTION This invention relates generally to interval timers, and more particularly to an interval timer having a fixed, locked time cycle.
Interval timers for controlling the functions of electrical apparatus, such as the oven of a domestic range, are well known. In one common form of range timer, the desired oven ON time and timed interval of opera tion are manually selected with the oven being turned ON at the time selectedand thereafter turned OFF upon expiration of the selected time interval. In other conventional range timers, both the desired timed interval and the desired termination time are simultaneously selected, the timer then initiating the ON function the desired timed interval in advance of the OFF time. In both conventional forms of range timers, the preselected timed interval can be changed or terminated during the course of the timed interval, i.e., the timed interval can be increased or decreased, as desired, or the automatic timing operation terminated, all by manual operation of the timer mechanism.
There are applications for interval timers, such as the timing of an automatic oven cleaning function in a domestic range, where it is desired that a predetermined ice fixed time interval be provided, and further that the timed interval, once initiated, proceed to its end without change in the interval or premature termination thereof.
In such automatic oven cleaning operations the internal temperature of the oven is raised to a very high level. Such ovens are insulated so that the outside temperature remains relatively cool even during the longest de signed cleaning cycle. The cleaning cycles normally also include a cool down period, at the end of the heat cleaning period, when the heating unit is deenergized for allowing the oven temperature to cool. If the cycle were interrupted before the end of this cool down period and reset to initiate another period of heat cleaning, the outside temperature of the oven might rise to an unacceptable level.
SUMMARY OF THE INVENTION It is accordingly an object of this invention to provide an improved interval timer.
It is another object of the present invention to provide an improved interval timer having a fixed and locked time cycle.
The invention, in accordance with one aspect thereof, provides interval timing apparatus having a fixed, locked time cycle. The interval timing apparatus includes 21 segmental gear having toothed and mutilated segments with means for manually rotating the segmental gear in one direction from an unset to a set position. A first pinion is rotatably mounted in fixed relationship with the segmental gear and is freely rotatable in the mutilated segment of the segmental gear. A second pinion is provided with means for rotatably mounting the second pinion for pivotal movement toward and away from the segmental gear. The second pinion is freely rotatable in the mutilated segment when the segmental gear is at its unset position and is urged towards mesh with the toothed segment when the segmental gear is rotated in the one direction away from its unset position. Drive means are provided for continuously rotating the first pinion. The mounting means for the second pinion is arranged to provide ratcheting of the toothed segment past the second pinion during manual rotation of the segmental gear in the one direction from its unset to its set position. The toothed segment moves into mesh with the first pinion at the set position of the segmental gear, thereby inhibiting further manual rotation of the segmental gear in either direction; the first pinion thereafter driving the segmental gear in the one direction from its set towards its unset position.
The above-mentioned and other features and objects of this invention and the manner of attaining them will become more apparent and the invention itself will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein:
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view of an interval timer apparatus incorporating the invention;
FIG. 2 is a fragmentary exploded view of a portion of the interval timer of FIG. 1;
FIG. 3 is a schematic view of the segmental gear and pinions of the interval timer of FIG. 1; and
FIG. 4 is a partial plan view of the face of the interval timer taken generally along the line 4-4 of FIG. 1.
3 DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the figures of the drawings, there is shown an interval timer apparatus generally indicated at 10. The timer apparatus includes a frame 12 having front and back plate elements 14, 16 maintained in spaced, assembled relation by a plurality of posts, one of which is shown at 18. A segmental gear 20 is provided secured to setting shaft 22 which extends between the front and back plate elements 14, 16 and is journaled therein. Setting shaft 22 has a portion 24 extending upwardly from front plate element 14, and setting knob 26 is secured thereto. An indicating pointer 28 is secured to the setting shaft extension 24, as shown.
Segmental gear 20 has a toothed segment 30 having leading and trailing edges 32 and 34, which define a mutilated segment 36 therebetween. As will hereinafter be described in more detail, segmental gear 20 is manually rotated by setting shaft 22 in the direction shown by the arrow 38 from an unset position to a set position, as shown in FIG. 4, the angular extent of this manual rotation being equal to the angular extent of the mutilated segment 36 of the segmental gear 20.
An idler gear 40 is provided mounted on setting shaft 22 and freely rotatable with respect thereto, idler gear 40 being a full gear and having the same number of teeth of the same pitch and pitch diameter as segmental gear 20 would have if it were a full gear, i.e., without the teeth removed therefrom to form the mutilated segment 36.
A first pinion assembly 42 is provided comprising identical pinions 44, 46 secured to shaft 48 and rotatable therewith. Shaft 48 extends between front and back plates 14, 16 and has its opposite ends respectively journaled therein. A second pinion assembly 50 is provided comprising identical pinions 52, 54 and a driving gear 56, all secured to shaft 58 and rotatable therewith. Shaft 58 extends between front and back plates 14, 16 and has its upper end 60 journaled in front plate element 14. Both pinion 44 of pinion assembly 42 and pinion 52 of pinion assembly 50 are at all times in mesh with idler gear 40. For ease of manufacture each of the pinion assemblies 42 and 50 is made as a unitary element. For instance the pinions 44 and 46 and the shaft 48 are formed from a single piece of material. Obviously, each of the pinion assemblies could be formed as individual elements securely joined so as to rotate together in proper alignment.
The lower end 62 of shaft 58 of pinion assembly 50 is journaled in end 64 of pivoted lever member 66 which has its other end 68 pivotally connected to back plate element 16 by pivot pin 70. An aperture 72 is provided in back plate element 16 with the outer edge 64 of pivoted lever member 66 which journals the lower end 62 of pinion shaft 58 being recessed therein, as best seen in FIG. 2. A hairpin spring 74 is provided having one end 76 engaging abutment 78 on back plate element 16, its central portion 80 surrounding pivot pin 70, and its other end 82 engaging abutment 84 on lever member 66. It will thus be seen that lever member 66 provides for pivotal movement of pinion 54 inwardly and outwardly with respect to segmental gear 20, such movement being accommodated by a somewhat loose journaling of the upper end 60 of pinion shaft 58 in the front plate element 14, and it will further be seen that the spring 74 normally biases pinion 54 radially inwardly toward segmental gear 20.
Pinion assembly 50 is continuously rotated by a conventional synchronous clock motor 86 which drives gear 56 through a conventional speed-reducing gear train 88.
It will be seen that the axes of segmental gear 20 (and thus of setting shaft 22 and idler gear 40), pinion assemblies 42 and 50, and the pivotal axis of lever member 66 are in spaced parallel relationship. Further, as seen in FIG. 3 and as will be hereinafter explained, the angle a defined by the pivotal axis of the lever member 66, the axis of pinion assembly 50, and the axis of segmental gear 20 is preferably greater than 90, the angle a be- 4 ing 110 in a specific embodiment. Also the angle a is disposed or positioned to encompass the leading edge 32 of the segmental gear when that gear is in its unset POSI- tion.
A cam 90 is attached to segmental gear 20 and is rotatable therewith. A pivoted cam follower lever 92 is provided having its outer end 94 cooperatively engaging the surface of cam 90 and being pivotally connected, intermediate its ends, to the back plate element 16, as at 96. The other end 98 of lever member 92 extends downwardly through another aperture 100 in back plate element 16 and actuates a suitable electric switch assembly 102 mounted on the bottom surface of back plate element 16. The switch assembly may take any one of a number of well-known forms, and thus it will not be further described here.
In a sequence timer apparatus intended for controlling an oven cleaning function, cam 90 actuates lever member 92 to actuate switch assembly 102 thereby to initiate the timed oven cleaning cycle when the setting shaft 22,
.24 and segmental gear 20 are manually rotated in direction 38 to the set position, cam 90 subsequently actuating lever member 92 to actuate switch 102 thereby to terminate the oven cleaning function when the segmental gear 20 has been further rotated in the direction 38 around to the unset position. Thus, in the illustrated embodiment, cam 90 is provided with a dwell portion 104 and a rise portion 106 proportional and arranged to provide the desired preset fixed timed interval. More specifically, for the sake of simplicity, cam 90 includes a single level rise portion 106 which would correspond to the period of time the oven door is latched closed. Very often the portion 106 could have various levels to control the switch assembly to cause the oven door latch to be closed; then the oven heating unit energized; then, after a period of cleaning the heating unit to be deenergized; and finally after a cooling period, the latch to be opened.
Pinions 46 and 54 of pinion assemblies 42 and 50 are both freely rotatable in the mutilated segment 36 of segmental gear 20 when segmental gear 20 and setting shaft 22, 24 are in the unset position. It will be seen that in this position, pinion assembly 50 is driven by motor 86 through gear train 88 and gear 56, pinion 54 thus driving idler gear 40 in the direction 38 which, in turn, continuously rotates pinion assembly 42. It will thus be seen that both pinion assemblies 42 and 50 together with the idler gear 40 are continuously driven by motor 86.
It will be seen that pinions 46 and 54 of pinion assemblies 42 and 50- are respectively located adjacent the trailing and leading edges 34 and 32 of toothed segment 30 of segmental gear 20 when the segmental gear 20 is in its unset position (FIG. 3). Thus, initial manual rotation of setting shaft 22, 24 and segmental gear 20 in the direction 38 away from the unset position toward the set position will move the teeth of toothed segment 30 of segmental gear 20 adjacent leading edge 32 into alignment with pinion 54 of pinion assembly 50. However, the provision of the clutch assembly comprising pivoted lever member 66 and spring 74 permits the teeth of toothed segment 30 to ratchet past pinion 54 as the manual rotation of segmental gear 20 continues in direction 38 toward the set position. Thus, motor 86 continues to drive pinion assemblies 50 and 42 and idler gear 40 despite the setting movement in the direction 38 of segmental gear 20, pinion 46 of pinion assembly 42 continuing to rotate freely in the mutilated segment 36 of segmented gear 20.
Initially, that is when pinion 46 is adjacent trailing edge 34 of gear 20, pinion 46 inhibits manual rotation of gear 20 in the other direction, that is in the direction of arrow 39. A manual force tending to rotate gear 20 in the other direction quickly brings the trailing edge 34 into contact with pinion 46. Since motor 86 is continuously driving pinion 46 such as to rotate gear 20 in the direction of arrow 38, pinion 46 strongly inhibits movement of gear 20 in the other direction.
After gear 20 has been rotated somewhat in the direction of arrow 38, but short of its set position, the pinion 46 will be spaced from both the leading and trailing edges and cannot inhibit manual rotation. However, in this intermediate position pinion 54 will inhibit manual rotaton. in the direction of arrow 39. In this position, the toothed segment 30 is in alignment with the pinion 54. A manual force tending to cause gear 20 to rotate in the direction of arrow 39 will cause the pinion 54 to firmly mesh with toothed segment 30. Since motor 86 is continuously driving pinion 54 such as to rotate gear 20 in the direction of arrow 38, pinion 54 will strongly inhibit rotation of gear 20 in the direction of arrow 39.
The capability of ratcheting toothed segment 30 past pinion 54 in one direction but not the other results from the mounting lever 66. The angle a defined by the pivoted axis 70 of lever 66, the axis of pinion 54 and the axis of segmental gear 20 is proportioned to be greater than 90, being about 110 in the exemplification. Also it is disposed to encompass the leading edge 32 of gear 20, when gear 20 is in its unset position. Thus a manual force tending to rotate gear 20 in the direction of arrow 38 will cause lever 66 to pivot about its axis 70 against spring 74. This will move pinion 54 away from gear 20 and allow toothed segment 30 to ratchet by the pinion. On the other hand, a manual force tending to rotate gear 20 in the direction of arrow 39 will cause toothed segment 30 and pinion 54 to firmly mesh so that pinion 54 strongly inhibits any such rotation in the direction of arrow 39.
When the segmental gear 20 has been manually rotated to its set position, the teeth of toothed segment 30 of segmental gear 20 adjacent the leading edge 32 move into mesh with pinion 46. When the first tooth at leading edge 32 moves into mesh with pinion 46, further manual rotation of segmental gear 20 is immediately inhibited by reason of the fact that pinion assembly 42 is mounted in fixed relationship with respect to segmental gear 20, it thus being impossible for pinion 46 to be moved out of meshing engagement with toothed segment 30 of segmental gear 20. As soon as the teeth of toothed segment 30 adjacent leading edge 32 have moved into mesh with pinion 46, segmental gear 20 is thereafter driven in direction 38 towards its unset position by motor 86, driving gear 56 on pinion assembly 50. It will be observed at this point that both pinions 54 and 46 are in mesh with toothed segment 30 of segmental gear 20, and thus are both driving segmental gear 20 in direction 38 by reason of the interconnection of pinions 54 and 44 by idler gear 40.
It will now be observed that when the timer has been set, i.e., is in its timing cycle, the predetermined, fixed time interval cannot be manually changed or terminated by reason of the fact that pinion 46 is in mesh with the toothed segment 30 of segmental gear 20, thus holding it in position against manual rotation, further rotation of segmental gear 20 in direction 38 being possible only by driving the same by pinions 46- and 54 which are driven by the motor 86.
Pinions 46 and 54, driven by the motor 86, now continue to drive segmental gear 20 in direction 38 toward its unset position. It will now be observed that at a rotational position of segmental gear 20 short of its OFF position by the angular extent of mutilated segment 36, pinion 54 will move off of the trailing edge 34 of toothed segment 30 so as again to freely rotate in mutilated segment 36, however pinion 46 remains in mesh with toothed segment 30 and is driven from pinion assembly 50 by idler gear 40, pinion 46 thus continuing to drive segmental gear 20 in direction 38 to its OFF position at which point pinion 46 moves off of trailing edge 34 of toothed segment 30 to again freely rotate in mutilated segment 36, thus terminating rotation of segmental gear 20 and the timing interval.
It will be readily seen that timing cam 20 may be provided with any desired configuration and sequence of rise and dwell portions so as to provide any desired sequence of functions; however, it will be understood that once the timed cycle has been initiated, these functions will automatically proceed without interruption or change until the end of the timed cycle.
It will now be seen that the invention provides an interval timer having a predetermined, fixed cycle which, once the cycle has been initiated, cannot be changed or terminated until the entire cycle has been completed.
While, in accordance with the patent statues, I have described what, at present, is considered to be the preferred embodiment of my invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention, and it is therefore aimed in the appended claims to cover all equivalent variations as fall within the true spirit and scope of the invention.
What I claim as new and desire to secure by Letters Patent of the United States is:
1. Interval timing apparatus for providing a fixed, locked time cycle comprising: a segmental gear having toothed and mutilated segments; means for manually rotating said segmental gear in one direction from an unset to a set position; a first pinion rotatably mounted in fixed spaced relationship with said segmental gear, said first pinion being freely rotatable in said mutilated segment; a second pinion; means for rotatably mounting said second pinion for pivotal movement toward and away from said segmental gear normally urging said second pinion toward said segmental gear; said second pinion being freely rotatable in said mutilated segment when said segmental gear is in its unset position and being urged toward mesh with said toothed segment when said segmental gear is rotated in said one direction away from its unset position; drive means for continuously rotating said first pinion; said mounting means for said second pinion being arranged to pemit ratcheting of a toothed segment of said second pinion during manual rotation of said segmental gear in said one direction from its unset to its set position, said toothed segment moving into mesh with said first pinion at the set position of said segmental gear thereby inhibiting further manual rotation of said segmental gear in either direction, said first pinion thereafter driving said segmental gear in said one direction from its set toward its unset position; switch means, and means for actuating said switch means responsive to predetermined rotational positions of said segmental gear.
2. The apparatus of claim 1 including drive means continuously rotating said second pinion with said first pinion; manual rotation of said sgmental gear in said one direction from its unset towards its set position bringing said toothed segment in alignment with said second pinion; said second pinion thereafter inhibiting manual rotation of said segmental gear in a direction opposite to said one direction.
3. The apparatus of claim 1 wherein said actuating means includes a cam mounted for rotational movement with said segmental gear, and a cooperating cam follower connected to said switch.
4. The apparatus of claim 1 wherein said toothed segment of said segmental gear has leading and trailing edges respectively defining said mutilated segment therebetween, both of said pinions being freely rotatable in register with said mutilated segment in the unset position of said segmental gear with said first pinion adjacent said leading edge; manual rotation of said segmental gear in said one direction away from its unset position toward its set position moving the teeth of said toothed segment adjacent said leading edge into mesh with said second pinion, continued manual rotation in said one direction toward said set position causing ratcheting of the teeth of said toothed segment past said second pinion; and manual rotation of said segmental gear in said one direction from its unset position moving said teeth adjacent said leading edge into mesh with said first pinion, thereby providing the set position for said segmental gear.
5. The apparatus of claim 4 wherein said first pinion is adjacent said trailing edge of said segmental gear when said segmental gear is in its unset position; manual force on said segmental gear tending to rotate said segmental gear from its unset position in a direction opposite said one direction bringing said trailing edge of said segmental gear into mesh with said first pinion to thereby restrain said segmental gear from such movement opposite said one direction.
6. The apparatus of claim 4 wherein said segmental gear is rotatable about a first axis; a lever member is pivoted about a second axis spaced from and parallel to said first axis; spring means resiliently urges said lever member toward said segmental gear; said second pinion being rotatably mounted on said lever member about an axis spaced from and parallel to said first and second axes; said first, second and third axes defining an angle greater than 90 positioned to encompass said leading edge of said segmental gear when said segmental gear is in its unset position.
References Cited RICHARD B. WILKINSON, Primary Examiner L. R. FRANKLIN, Assistant Examiner US. Cl. X.R. 5839.5