US2833347A - Timing mechanism - Google Patents

Description

y 6, 1958 P. v. TERRY TIMING MECHANISM Filed Dec. 26. 1953 lnvenror: Paul V. Terry His AHorney United States Patent TIMING MECHANISM Paul V. Terry, Eliot, Maine, assignor to General Electric Company, a corporation of New York Application December 26, 1956, Serial No. 630,630

6 Claims. (Cl. 161-1) This invention relates generally to timing mechanisms and more particularly to a novel form of escapement mechanism which provides a rugged, simple, low-cost timing mechanism utilizing a minimum number of moving parts.

In general, mechanical timing mechanisms heretofore available have utilized rather complex mechanisms which ordinarily include delicate escapement mechanisms, resulting in a device that must be handled with care in order to avoid damage thereto. Such mechanisms may have a high degree of precision and provide for extremely accurate timing where required, but for those applications wherein precision timing is not required and a rugged, low-cost timing mechanism is desired, the aforesaid delicate mechanical timers are not suitable even though in some instances low-cost timers could be manufactured at the sacrifice of precision.

The present invention has for its primary object the provision of a timing mechanism which overcomes the disadvantages of conventional mechanical timing mechanismsby replacing the delicate mechanical escapement mechanisms with a fluid-type escapement that is not only uncomplicated in design but is also rugged and easily and inexpensively manufactured.

In one aspect, the invention comprises a flexible closed container which confines a flowable material and is arranged to have a substantially uniform cross-sectional area throughout its length. A roller or other similar bearing member may be arranged to press against the flexible container and reduce its cross-sectional area in a portion thereof. By making the container and the bearing member relatively movable and deriving relative motion from an energy-storing member such as a spring or the like, the stored energy may 'be released at a controlled rate determined by the flow of the material within the container through the portion of reduced crossseetional area. The design is such that timing action may be easily and conveniently regulated.

The invention, together with its objects and advantages, will be more readily understood upon reference to the following description when taken in conjunction with the drawing annexed hereto, in which:

Figure 1 is an exploded view of a timer constructed in accordance with the invention; and

Figure 2 is a plan view of the fluid escapement mechanism utilized in the mechanism of Figure 1.

Referring now to the drawings, it is seen that the timing mechanism includes a shaft 3 which may be suitably journalled between a pair of support plates 4, 5, one end of the shaft extending through plate 4 and having afiixed thereon a timing dial 6 and a setting knob 7. Plates 4, 5 may have suitable apertures in the corners thereof in which may be mounted suitable posts for securing the plates together in spaced relationship. Dial 6 may be provided with a suitable scale 8 which cooperates with a fixed reference member 9 mounted on plate 4 to indicate the setting of the timer.

In the illustrated embodiment of the timing mecha- Patented May 6, 1958 ice nism, it has been shown in combination with an electrical switch comprising the contact carrying switch blades 11, 12 mounted on plate 5 which cooperate with a cam 13 secured to shaft 3 to obtain timed switching as required.

The timing mechanism includes a conventional spirally formed clock-type spring 14 in which energy may be stored for timing purposes, one end of the spring being aflixed to a pin 15 secured in plate 4 with the other end of the spring attached to an arcuate. leaf spring 16.

The leaf spring 16 couples the spring to the novel fluid escapement mechanism which comprises a closed container in the form of a flexible tube 17 within which is confined a suitable flowable material. The material within the tube may be selected from a variety of liquid or semi-liquid materials, one of which may be silicone putty which has been found to work very Well. Various oils and greases may be used and in fact, it has been found that water may be used with some success, but no matter what is selected, it is important to use one whose viscosity does not change significantly with changes in temperature.

The flexible tube has a substantially uniform crosssectional area throughout its length and is wrapped around a drum 18 which is secured to shaft 3 with the ends of the tube being brought through a slot 19 provided in the peripheral surface of the drum. Th leaf spring 16 is arranged within the drum 18 and presses against the ends of the tube 17 to not only hold the tube in place on the drum, but to seal the ends as desired.

From the above, it is apparent that the timing mechanism may be set by moving the knob 7 in the direction of the arrow shown on dial 6 which has the effect of winding up the spring 14 to store energy therein, the drum 18 rotating as the spring is wound up. When the knob 7 is released, the spring will unwind and rotate the drum 18 in the opposite direction. To regulate the release of energy'from spring 14 in a timed manner, a.

bearing member in the form of a roller 21 suitably journalled on a shaft 22 is arranged to press against tube 17, in such a way that a portion of the tube has its crossectional area reduced. So long as the roller 21 is hearing against the tube 17, it is apparent that the rate at which the spring 14 unwinds will be determined by the flow of the material within the tube through the section of reduced cross-sectional area.

In order to have the roller 21 pressing against tube 17, the roller shaft 22 is mounted on an arm 23 which in turn has one end pivotally mounted at 24 on plate 5.

The other end of arm 23 has one end of a biasing spring 25 connected thereto with the other end of the biasing spring connected to plate 5. This end of the arm is pro-vided with a flange 26 to which the spring 25 is connected and in which is mounted an adjusting screw 27 which cooperates with a stop 28 formed in the plate 5.

With the above arrangement of parts in mind, it is seen that the spring 25 at all times urges the rolller 21 against the tube 17 with the screw 27 and associated stop 28 providing an adjustable arrangement for limiting the degree to which the roller 21 bears against the flexible tube 17.

In operation of the aforesaid timing mechanism, the setting knob 7 is turned rather rapidly so that the drum 18 and its associated flexible tube 17 is rotated at a speed which is greater than would be allowed by the flow of material within the tube through the section of reduced cross-sectional area. In this manner the roller 21 is forced outward with suflicient force to overcome the biasing action of spring 25, thereby permitting the arm 23 to pivot outwardly away from the drum to allow the flexible tube to pass freely by the roller for convenience of setting.

Once the timer has been set, which could be anywhere along the scale 8, the knob 7 is released and the spring 14' will begin. unwinding but the roller 21 willnow functionv to control the speed of rotation of. drum 18 and thus control the angular velocity of shaft 3 which in turn.

will control the angular velocity of the cam 13 asrequired.

The timing actionmay be regulated during manufacture by utilizing materials of different viscositics within the tube 17 or it may be regulated by selecting springs of varying torques for the spring member 14 forming a part of the timer. The timer may also be regulated during manufacture or in, subsequent use by merely adjusting the screw 27 to alter the bearing effect of roller 21.

All. of the parts, which. make up the timer may be easily and inexpensively manufactured and a wide latitude is permitted in the selection of materials for regulating timing action. Moreover, a minimum number of moving parts is utilized in the design, and adjustment during use is easily accomplished with no more than a screw driver for regulating the position of screw 27. The mechanism is also quite rugged and may be used for many applications without requiring any particular care in the handling thereof.

Therefore, while a particular embodiment of the subject, invention has been shown and described herein, it is in the nature of description rather than limitation, and' it will occur to those skilled in the'art that various changes, modifications, and combinations may be made within the province of the appended claims, and without departing either in spirit or scope from this invention in its, broader aspects.

What I claimas new and desire to secure by Letters Patent of the United States is:

1. In a timing. mechanism, in combination: means for storing energy, a flexible closed container having a flowa'ble material therein, said container having a uniform cross-sectional area throughout its length, means bearing against said container to reduce said cross-sectional area ina portion of said container, and means coupled to said energy storing means for moving said container and said bearing means relative to each other to release said stored energy at a controlled rate, said flowa'ble material flowing through said portion of reduced cross-sectional area to control the relative velocity of said container and said bearing means.

2. In a timing mechanism, in combination: spring means for storing energy, a flexible closed tube having a flowable material therein, said tube having a uniform cross-sectional area throughout its length, roller means bearing against said tube to reduce said cross-sectional area in a portion of said tube and means coupling said tube to said spring means for. moving said tube relative to said roller means to release the energy stored in said spring at a controlled rate, said flowable material flowing through said portion of reduced cross-sectional area to control the velocity of said tube relative to said roller means.

3. In a timing mechanism, in combination: spring means for storing energy, a rotatably mounted drum, a flexible closed tube wrapped around said drum, said tube containing a fiowable material and having a uniform cross-sectional area throughout its length, a roller bearing against. said tube to reduce said cross-sectional. area in a portion of said tube, and means connecting saiddrum to said spring means whereby said drum rotates upon release of the energy stored in said spring, said. tube moving relative to said roller upon rotation of said drum, said flowable material flowing through said portion of reduced cross-sectional area to control the speed of rotation of said drum to thereby regulate the rate at which energy stored in said spring is released.

4. The combination defined by claim 3 wherein said roller is held against said tube by means of a biasing.

spring coupled thereto.

5. The combination defined by claim. 4 wherein said roller is rotatably mounted on a pivotally mounted arm, with said biasing spring connected to said arm, said arm having adjustable stop means for controlling the degree to which said roller bears against said tube.

6. The combination defined by claim 5 wherein! said energy storing spring is spirally arranged within said.

drum and has one end connected thereto with its other end connectedvto a fixed support, said drum is mounted on a shaft and. a setting knob and a dial are mounted on said shaft.

References Cited in theme of this patent UNITED STATES PATENTS 2,158,624 Gregory May 16, 1939 2,276,494 Kellogg Mar. 17, 1942 2,460,116 Bazley Ian. 25, 1949 2,466,327 Rieber Apr. 5, 1949 2,755,349 Silvers July 17, I956

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