US2940720A - Time delay device - Google Patents

Description

June 14, 21960 R. G. BlRR 2,940,720

TIME DELAY DEVICE Original Filed Nov. 2'1. 195:

I09. I07 I08 "UINVENTOR.

TIME DELAY DEVICE Rudolph G. Birr, Lombard, iih, assignor, by mesne assignments, to Steiner American Corporation, Salt Lake City, Utah, a corporation of Nevada Original application Nov. 27, 1953, Ser. No. 394,528,

now Patent No. 2,899,251, dated Aug. 11, 1959. Divided and this application May 2, 1955, Ser. No. 505,353

'6 Claims. (Cl. 248-609) The present application is a division of my co-pending application, Serial No. 394,528, filed November 27, 1953, now Patent No. 2,899,251, issued August 11, 1959, and the invention herein disclosed and claimed relates to improvements in time delay devices of the vacuum cup type.

Time delay devices of the vacuum cup type have heretofore been used in a variety of installations where a time delay is desired between two successive operations in mechanisms. For example, time delay devices of the vacuum cup type have heretofore been employed in towel dispensing cabinets for introducing a delay period between the termination of a dispensing operation and the next succeeding one, one of the purposes being to prevent the waste of toweling that would otherwise occur if the user could withdraw one length of toweling after another from the dispenser without a delay between successive withdrawals. The prior time delay devices of this type have included a pair of engageable vacuum cups and an adjustable air valve for metering air into the area between the compressed cups for determining the length of time that the cups remain compressed together and, thus, for determining the time delay between successive operations. The air valves in these prior vacuum cup time delay devices have ordinarily included a screw type valve stem that has cooperated with an air port or orifice to determine the rate at which air is introduced or permitted to flow into the compressed vacuum cups, thereby controlling the time interval or the time required to cause the two vacuum cups to separate and thereupon permit or cause the next operation to take place. If the valve stem in these prior devices is screwed down into the air port or orifice with any force, however, the cooperating orifice, as well as the valve stem, is often sufiiciently damaged and distorted to render the timing mechanism useless. Furthermore, shocks and vibrations to which these prior timing devices have often been subjected, have caused the valve stems to change their positions and thereby inadvertently alter the time delay period desired between successive operations.

One of the objects of the present invention is to provide an improved time delay device of the vacuum cup type which avoids the above-mentioned disadvantages of the prior devices. Another object of the invention is to provide an improved time delay device of the vacuum cup type including a valve mechanism that may be adjusted to vary the timing interval by controlling the movement of a valve stem in such a manner that it cannot jam or distort the cooperating orifice of the air vent with which it cooperates.

These and other objects and advantages of the present invention will best be understood from the following description of a preferred embodiment thereof taken with the single view in the accompanying drawing, said view being an enlarged section taken substantially along the longitudinal axis or center line of a time delay device constructed in accordance with the present invention.

In the drawing, the present time delay device is shown Patented June 14, 1960 ice to be mounted on an upright wall 51 that may be any suitable wall or frame of the apparatus with which the device is to be employed. For example, in the abovementioned Patent No. 2,899,251, of which the present application is a division, a time delay device identical to the present one is shown to be mounted upon an upright inner wall of a towel dispensing cabinet. Secured to the wall 51 in any suitable fashion, such as by screws not shown, there is a channel-shaped member 87 having vertically spaced apart upper and lower arms 107 and 96 that are joined at their inner ends by a vertical web having an embossment 88 formed thereon with a vertically extending slot 89 provided in the embossment. This slot, as will be explained more fully hereinafter, serves as a vertical guide for a bracket 102 which carries a valve needle 100 of the time delay device.

A compressible vacuum cup 90, of rubber or the like, having a centrally located small air vent 91 therein is demountably secured on the shoulders formed on the lower end of a stud 92, the upper end 93 of the stud being encompassed by a coil spring 94 with an intermediate threaded portion 95 of the stud extending through an opening in the lower arm 96 of the channel-shaped member 87. A nut 97, preferably of the self-locking type, engages the threaded portion 95 of the stud and secures the stud and its detachable vacuum cup in place on the lower arm 96 of the channel-shaped member, as illustrated in the drawing. A central air passage 93 extends through the entire length of the stud 92, the lower portion of the passage being of reduced diameter to provide a valve seat for an air vent or orifice 99 provided at the lowermost end of the passage 98 and in direct alignment with the air vent 91 of the vacuum cup 90.

A needle valve having a tapered lower end 101 is s'lidably carried in the central opening 98 of the stud so that it can be moved longitudinally toward and away from the air vent or orifice 99 and thus vary the rate at which air may pass therethrough and into the cavity of the vacuum cup 90. v

In one embodiment of the present device used by applicant in the towel dispensing cabinet shown and claimed in the aforesaid Patent No. 2,899,251, the following dimensions have been found to be quite satisfactory in controlling the passage of air through the air vent 91 in the cup 90. In that embodiment the central opening 98 is one-sixteenth of an inch in diameter, the air vent or orifice 99 is .035 inch in diameter, the needle valve 100 at itsupper end is .040 inch in diameter, the bottom of the tapered end 101 of the needle valve is .034 inch in diameter and is tapered upwardly and outwardly therefrom at one-fourth of an inch per foot. With this arrangement, the needle valve 100 when moved vertically approximately one-sixteenth of an inch from a shut-off position, will provide an annular opening of approxb mately .0005 inch between the needle valve 100 and the wall of the orifice 99. It will be apparent to those skilled in the art that these dimensions may be varied to control the amount of air that will pass through the orifice 99 and into the cavity of the vacuum cup 90, but the desired adjustment can be satisfactorily made with the dimensions given above.

In assembling the time delay device, which is designated generally by the numeral 86 in the drawing, the needle valve 100 is preferably first placed into the cen tral opening 98 of the stud 92 with the lower tapered end 101 of the needle seated in the orifice 99 so as to completely close the samef A needle guide bracket 102 is then secured to the upper end of the needle 100 with the bottom-of the bracket inengagement with the upper end of the stud 9'2 and with the right hand end 103 of the bracket 102 extending into and residing in the guide slot 89. The opposite or outer end of the needle guide bracket 102, it will be observed, is folded back on itself. to adjustably clamp the needle 100 therebetween and it is arranged so that a screw 104 may be inserted into the folded over portion and threaded into a tapped hole in the main part of the bracket 102. so as to tightly lock the bracket 102 and the needle valve 100 together and in their adjusted relationship. The coil spring 94, surrounding the upper end of the stud 93, of course, will be in a compressed condition during this assembly and will be hearing at its upper end on the bracket 102 when the bracket 102 is fastened to the upper end of the needle 100.

The upper end of the needle valve 100 projects above the needle guide bracket 102 and extends freely into an opening provided in the lower end of a time adjusting scr'ew105. The .screw 105 is threaded along substantially its entire length and may be provided at its upper end with a knurled knob or thumb nut portion 106. As seen in the drawings, the upper arm 107 of the channel member 87 is provided with a guide hole 108 which is of snfiicient diameter to clear the threads of the adjusting screw 105, and the arm is provided with an adjacent narrow elongated slot 109 for receiving the free ends of a U-shaped adjusting screw tension spring 110, only one leg of the U-shaped spring being seen in the drawing inasmuch as the other leg has been cut away in the view. Each of the free ends of the U-shaped spring are turned upwardly through the slot 109 and then outwardly to provide projections 111 which bear against the upper surface of the arm 107 at the opposite ends of the slot 109 for securing the spring in the slot 109 and for holding the two long legs of the spring 110 in engagement with the lower surface of the upper arm 107. In this position the inside surfaces of the two legs of the U-shaped spring straddle the screw 105 and are in clamping engagement with the threads thereof on opposite sides of the screw. In order to mount the U-shaped tension spring 110 in the slot 109 in the manner described, the projections 111 thereon are pinched or flexed toward each other and theninserted upwardly through the slot 109. The projections 111 or free ends of the spring are then released so that the projections spring apart and overlie the upper surface of the arm 107 at the opposite ends of the slot 109, thereby to hold the U-shaped tension spring 110 in the position illustrated. Thereafter, the adjusting screw 105 may be inserted into the guide hole 108 until the lower threads of the screw encounter the opposite inner sides of the U-shaped tension spring 110 which act as cooperating threads with the threads on the adjusting screw 105 so that the screw may be turned down until its lower end arrives in contact with the upper surface of the bracket 102, as shown in the drawing.

Beneath the vacuum cup 90 there is a second or lower vacuum cup 85' mounted upon the upper end of an upstanding and vertically movable stud 82 which may be suitably attached to the apparatus that is to be controlled by the present time delay device. For example, as shown in the aforementioned Patent No. 2,899,251, the stud 82 may be mechanically attached to a stop mechanism for preventing the withdrawal of toweling from a towel dispensing cabinet. In. such an installation the stop mechanism may be inactive, thereby permitting the withdrawal of toweling, when the stud 82 is in the lowered position shown in the present drawing, in which position the lower vacuum cup 85 is separated from the upper vacuum cup 90. On the other hand, when the stud 82 is raised to bring the lower vacuum cup 85 into pressed contact with the upper vacuum cup 90, the stop mechanism may be in an activated condition so as to prevent the withdrawal of toweling. When the lower stud 82 is raised to bring the lower vacuum cup 85 into pressed contact with the downwardly facing cavity end of the upper cup 90, the two vacuum cups will adhere to each other, thereby retaining the lower stud 82 in its raised position until the time delay device times outthat is, until sufiicient air is permitted to be metered into the cavity of the two engaged vacuum cups through the orifice 91 of the cup 90 to permit the two cups to separate. In the installation just referred to, the separation of the two cups will permit the lower stud 82 to drop to the position thereof shown in the drawing, thereby deactivating the stop mechanism in the towel dispensing cabinet so as to permit the withdrawal of further toweling therefrom. It will, of course, be appreciated by those skilled in the art that, while the present time delay apparatus may be used to advantage in such devices as towel dispensing mechanisms and cabinets, as just explained, the time delay device may also be utilized to advantage in other installations.

One important feature of the adjusting screw 105 and the U-shaped tension spring 110 is that the adjusting screw 105 cannot be used to force or jam the needle 100 downwardly into the orifice 99. This advantage arises due to the fact that the U-shaped tension spring 110 acts as a clutch and will slip over or skip from thread to thread on the adjusting screw 105 if the latter screw is further turned downwardly after the needle guide bracket 102 has engaged its stop position in contact with the upper end of the stud 92. Thus, the guide bracket 102 itself acts as a stop and the U-shaped tension spring 110 acts as a slip clutch to provide double protection preventing the needle 100 from being forcefully driven into the orifice 99. The clamping or gripping action of the spring 110 on the screw 105 also tends to prevent inadvertent turning of the screw by vibrations and the like to which the device may be subjected. When the-adjusting screw 105 is manually turned to withdraw or raise the needle 100 from its closed or shut-ofi position, the U-shaped spring 110 cooperates with the threads of the screw in a normal threading manner and the coil spring 94 expands to slide the needle 100 and its guide bracket 102 asa unitary body upwardly. During this normal raising adjustment of the needle 100 and its bracket 102, andduring the corresponding but reverse normal lowering adjustment, the end 103 of the needle valve guide bracket 102 slides vertically in the guide slot 89 and cooperates therewith to prevent the needle valve 100 from turning in either direction during rotation of the adjusting screw 105.

From the foregoing description of the present time delay device 'it will readily be understood that when the vacuum cups and 90 have been compressed together, the releasing time required to separate them will be determined by the rate at which air is permitted to pass through the orifice 99 and the-vent 91 into the cavities of the vacuum cups. Thus, the releasing time may be accurately adjusted by turning the screw 105 to govern the position of the tapered end 101 of the needle in the orifice 99. Although the screw bears freely upon the upper side of the guide bracket 102 and is independent of the needle or valve stem 100, turning of the screw is effective to adjust the needle axially in either direction inasmuch as the compression spring 94 constantly bears upon the lower side of the guide bracket and constantly urgesthe bracket and the needle toward open position and the bracket into contact with the lower end ofthe screw 105.

Whileone preferred embodiment of the present time delay device has been shown in the accompanying drawing and has been described above, it will be understood by those skilled in the art that various modifications may be made therein which fall within the spirit and scope of the appended claims.

What is claimed is:

l. Mechanism for selectively controlling the timing interval of a time delay device of the vacuum cup type, comprising: means providing a valve body having an air passage therethrough, a valve seat in said air passage through which air may be introduced to the vacuum cup of the time delay device to annul the vacuum thereunder, a valve stem in said air passage having one of its ends extending exteriorly of said valve body and its other end adapted to cooperate with said valve seat, an adjusting screw for selectively moving said valve stem axially in said air passage between an open position and a closed position with respect to said valve seat to vary the rate at which air will pass through said air passage and thereby vary said time interval, and a stop bracket adjustably secured upon said exteriorly extending end of said valve stem and arranged to engage the exterior of said valve body when said valve stem is in said closed position, to prevent jamming of said valve stem into said valve seat beyond said closed position.

2. Mechanism for selectively controlling the timing interval of a time delay device of the vacuum cup type, comprising: means providing a valve body having an air passage therethrough, a valve seat in said air passage through which air may be introduced to the vacuum cup of the time delay device to annul the vacuum thereunder, a valve stem in said air passage having one of its ends extending exteriorly of said valve body and its other end adapted to cooperate with said valve seat, a stop bracket adjustably secured upon said exteriorly extending end of said valve stem and arranged to engage the exterior of said valve body when said valve stem is in its closed position to prevent jamming of said valve stem into said valve seat beyond said closed position, spring means urging said valve stem toward an open position with respect to said valve seat, and an adjustable screw independent of said valve stem and bearing freely upon said bracket for selectively moving said valve stem axially in said air passage between said open and closed positions to vary the rate at which air will pass through said air passage and thereby vary said time interval.

3. Mechanism for selectively controlling the timing interval of a time delay device of the vacuum cup type, comprising: means providing a valve body having an air passage therethrough, a valve seat in said air passage through which air may be introduced to the vacuum cup of the time delay device to annul the vacuum thereunder, a valve stem in said air passage having one of its ends extending exteriorly of said valve body and its other end adapted to cooperate with said valve seat, a stop bracket adjustably secured upon said exteriorly extending end of said valve stem and arranged to engage the exterior of said valve body when said valve stem is in its closed position to prevent jamming of said valve stem into said valve seat beyond said closed position, spring means bearing upon one side of said bracket and urging said valve 8 stem toward an open position with respect to said valve seat, and an adjustable screw independent of said valve stem and bearing on the other side of said bracket for selectively moving said valve stem axially in said air passage between said open and closed positions to vary the rate at which air will pass through said air passage and thereby vary said time interval.

4. Mechanism for selectively controlling the timing interval of a time delay device of the vacuum cup type, comprising: means providing a valve body having an air passage therethrough, a valve seat in said air passage through which air may be introduced to the vacuum cup of the time delay device to annul the vacuum thereunder, a valve stem in said air passage having one of its ends extending exteriorly of said valve body and its other end adapted to cooperate with said valve seat, a stop bracket adjustably secured upon said exteriorly extending end of said valve stem and arranged to engage the exterior of said valve body when said valve stem is in its closed position to prevent jamming of said valve stem into said valve seat beyond said closed position, spring means urging said valve stem toward an open position with respect to said valve seat, an adjustable screw independent of said valve stem and bearing freely upon said bracket for selectively moving said valve stem axially in said air passage between said open and closed positions to vary the rate at which air will pass through said air passage and thereby vary said time interval, and guide means for guiding said bracket to prevent rotation of said bracket and said valve stem during rotation of said screw.

5. The combination set forth in claim 4, wherein said guide means comprises a laterally projecting member on said bracket and a stationary plate having a longitudinally extending slot therein slidably receiving said projecting member.

6. The combination set forth in claim 4, wherein said adjusting screw cooperates with a slip clutch to avoid jamming of said valve stem into said valve seat by continued rotation of said screw after said valve stem has been moved to full closed position with respect to said valve seat.

References Cited in the file of this patent UNITED STATES PATENTS 2,135,767 Price et a1. Nov. 8, 1938 2,149,848 Lampel Mar. 7, 1939 2,298,882 Grunwald Oct. 13, 1942 2,464,782 Birr Mar. 22, 1949 2,516,825 Hejduk et a1 July 25, 1959

Images