US1517541A - Pressure-control device for switches - Google Patents

Description

J. H. DENNEDY PRESSURE CONTROL DEVICE FOR SWITCHES Filed June 29;

nQento'l James H vewnady PATENT OFFICE.

JAMES H. DENNEDY, 0F DETROIT, MICHIGAN rnnss'nnn-oonrnon DEVICE r012. swrrcnm.

Application filled June 29, 1922. Serial No. 571,680.

To all whom itmay concern:

Be it known that 1,. JAMES H. DENNEDY, a citizen ofthe United States, residing at Detroit, county of lVayne; State of Michigan, have invented a certain new and useful Improvement in Pressure-Control Devices for Switches, and declare the following to be a full, clear, and exact description of the same, such as will enable others skilled in the art to which it pertains to make and use the same, reference being bad to the accompanying drawings, which form a part of this specification. p

This invention relates to pressure controlled switches for refrigerating systems or other apparatus carrying a, fluid under a var riable'pressure, and the object of the invention is to provide a switch mechanismand apparatus for operating the switch controlled by the pressure of fluid as for instance the fluid in the low pressure side of the circulating system for an artificial refrigerating apparatus. The particular features of the invention are involved in the structure and relationship 'of parts of the control mechanism subject to influence of variation of pressure and in the combination therewith of an electric switch for making and breaking the circuit of an electric motor operatingthe apparatus. These objects and the. several novel features of the invention are hereinafter more fully described and claimed, and the preferred form of construction of a device embodyingm invention is shown in the'accompanying' rawings in which I Fig. 1 is a vertical longitudinal section of my improved switch and control apparatus showing the switch open.

Fi 2 is a similar'view showing the switch closed. I

Fig. 3 is a plan view of the switch mechanism.

In the usual artificial refrigerating system, a compressor is utilized in conjuction with a circulating system having a high and low pressure side and an electric motor for operating the compressor. This structureembodies the combination with a switch device for making and breaking the circuit of a motor of apparatus sub'ect to influence of variation in pressure of t e low pressure side of the circulating system and while the refrigerating system in its entirety has not here been shown the operation-of the device will be readily understood by those familiar with the art. The low pressure line of the circulating system is indicated at 1 and a branch 2 leads from this line to the casing 3 of the control device. Within this case is a deeply corrugated cylindrical bellows member iknown to the trade asa sylphon, the lower end of which is sealed to a plate 5 and the upper. end of which is sealed to a plate 6 that is securely fastened between the cap member 7 and the flange 8 of the easing 3. This provides a chamber 9 between the bellows member and wall of the member 3 sealed to atmosphere into which the line 2 opens It is to be observed that I have shown the line 2 as being the low pressure side of the circulating system of artificial refrigerating apparatus whereby the chamber 9 is subject to variation in pressure, but it is to be understood that any approved means may be employed to vary the pressure in the chamber 2 by a temperature change as for instance the Well known method of supplying a volatile fluid in the chamber vaporizin under certain high temperature and condensing under low temperature or the usual sensitive bulb may be employed connected to the apparatus in the same manner as here'shown with the line 2. The plate 5 at the lower end of the bellows member is secured and sealed to the central shaft 10 which extends upward through a threaded plug 11 in the\upper end of the cap member. This member 11 is provided with a central square or hexagonal aperture 12 and. the

shaft is threads to receive a nut 13 flanged at the lower end as shown and having a square or hexagonal body that may enter the aperture 12 of the plug 11.- The threads -on the outside of-the plug 11 and the threads on the inside of the nut 13 have the same pitch and number of threads per inch. The plug 11 is preferably provided with a series of apertures 14 for insertion of. a pin to be utilized in turning the nut or plug, and the plug 11 and nut 13 providefor an adjustment without altering .the relative positions of plug 11 and the nut 13 as is hereinafter stated. Within the bellows member and about the shaft 10 is a coiled. compression spring 15 seating against the plate 5 at the bottom and in, the plu '11 at the top and tend to force the mem er 5 downward expanding the bellows member. The switch is so constructed that this'movement downward by the spring forces the shaft 10 downward due to ltS' attachment to the bellows member and opens the switch and on the contra pressure developing in the pipe line 1 and dliamber 9 forcesthe plate upward against the tension of the spring compressing the bellows raising the shaft 10 which closes the switch.

The character of the electric switch structure is not material to this invention as various structures can be utilized that will make or break the circuit by movement of the shaft 10. The preferred type of switch here shown comprises a base 16 of insulating material that is carried on the cap member 7 by means of studs 17 of which there are several. On this base is mounted a frame consisting of the side plates 18 and 19 as will beunderstood from Fig. 3. A shaft 20 extends through the two side frames at one end and on the outer side of each frame is pivotally mounted a lever 21 formed at the rear end with outturned flanges 22 and 23 in'V form and also with terminal out turned flanges 24 and .25. The end 26 of each lever 21 is adapted for engagement with the respective contact member 27 or 28 as the case may be; there being two levers 21 and a contact member 27 and 28 for the res ective levers. The circuit 90, 91' of the e ectric motor is connected with these contacts 27 and 28 and when the end 26 of the levers 21 is passed between the blades of the members 27 and 28 the circuit is completed. The levers 21 are operatedby the U member 29 pivotally mounted on a shaft 30 extending through the two frame members 18 and 19 and the ends 31 of this member 29 lie between the flanges 22, 23 etc,

of the pin 32 extends between the adjacent ends of these two parts of the levers 34 as will be understood from Fig. 3. Near the pivot point of the lever 34 is a shaft- 36 extending between the two parts of the lever 34 and pivotally mounted on this shaft and extending downwardly therefrom is a link 37 which is pivotally connected at 38 with a link 39 which in turn is pivoted at 40 to a link 41 pivotally sup orted on the shaft 30. There are prefera 1y two links 39 and supported therebetween is a shaft 42 on which is pivotall mounted the threaded stub shaft 43. T e upper end of the shaft 10 of the -control device, as will be understood from Fig. 1, has a threaded portion 44 and a right and left handv threaded nut 45 is provided into which this end 44 of the shaft 10 and the threaded end of the shaft 43 extend thus connecting the links 39 with the shaft 10.

The two part lever 34 above mentioned has an arcuate slot 45 near the end to which the pin 32 is pivoted and through this slot extends the shaft 30 and which limits the movement of the composite lever 34 on its pivot. 1th the parts in the position shown in Fig. 2, pressure in the line 1 has raised the plate 5 and shaft 10 closing the switch and completing the circuit. This movement of the parts is from the position shown in Fig. 1 to that shown in Fig. 2. It will be seen on examining Fig. 1, that on upward movement ofthe shaft 10 due to its connection by means of the stub shaft 43 with the links 39 and the links 37, the lever 34 would be gradually moved upward about its pivot. This movementraises the pivot point'33 of the pin 32 upward compressing the spring 35 and as this ivot point passes the center line between t e aperture in the yoke member 29 and shaft 30 thereof, the spring will act to depress the end of the yoke 29 raising the opposite end 31. Due to the flanges 24 and 22 the end 31 of the member 29 by engaging first against the flange 24 begins to turn the lever 21 and then engages the flange 22 comparatively close to the pivot point of the lever 21 which causes a quick movement of the end 26 in engaging the corn tact 27. This action of the ends 31 of the yoke in relation to the levers 21 is the same either in the upward or the downward movement. The upward movement is caused by of the nut 13 is below t e web of the plug 11. This flange limits the upward movement of the shaft 10 and plate 5 so that excess pressure in the line 1 cannot be transferred to the switch machanism and by adjustment of the plug 11 and nut 13 required latitude of movement of the switch is .provided and the mechanism safeguarded from pressure The plug 11 is made adjustable to vary the tension of the spring 15. Also the bellows member is prevented from too great elongation or compression as the plate 5 limits the expanding movement of the bellows member and the nut 13 of the compression movement. I have here shown and described a particular switch structure. As heretofore stated it is to be understood that various switch structures may be utilized with this control device and it is also to be understood that the switch structure may be arranged to break the circuit on an increase of pressure and to close the circuit on a decrease of pressure in the chamber 9 which is exactly the reverse of the operation of the switch here shown and described.

With a device of this character, control of the operation of the artificial refrigerating apparatus or other devices is secured by astructure that is simple and efficient in character and when used with artificial'refrigerating apparatus, temperature may be controlled by variation in ressure of the low pressure line or expansion side of the system rather than by use of a thermostat as has ordinarily been the practice. By setting this mechanism to close the switch upon certain increase of pressure in the low pressure line the pressure of the low pressure line is maintained between certain limits which determines the cooling effect. Furthermore, by use of the specific switch mechanism as herein described, a slight movement of the shaft 10 may cause the maximum movement of the switch arm 21. This occurs by reason of the peculiarleverage utilized and in the particular relationship of the actuator member 31 and the lever 21 causing a quick make or break of the contact. However, my pressure actuated device may be used with various types of apparatus in which it is necessary or useful to make or break a circuit upon decrease or increase in pressure of a fluid subject to variation in pressure.

-Having thus fully described my invention, what I claim 1s 1. In pressure actuated mechanism for con- 'trol of electric switches, the combination with. an electric switch having a member movable to make or break a circuit through-the switch, of a pressure controlled mechanism for moving the member comprising a casing, a bellows like member therein expansible or contractible longitudinally and providing a chamber on the exterior thereof sealed to atmosphere and open to influence of fluid having a variable ressure, a rod secured to an end of the bellows member, a cap for the casing supporting the switch, said cap having an opening therethrough whereby the interior of the bellows member is open to atmosphere, the rod extending through the said aperture to ya movable part of the switch and being threaded, a nut on the rod adjacent the said aperture adjustable longitudinally of the rod and limiting the extent of compression movement'of the bellows member whereby the switch mechanism is rotected from excess pressure, and a coi ed spring within the bellows member tending to expand the same on certain reduction of pressure in the chamber.

2. In pressure actuated mechanism, the combination with a device movable under control of said mechanism, of a casing comprising a body portion and a cover, a cylindrical corrugated bellows within the casing having one end in sealed attachment to the cover, a plate closing the other end of the corrugated bellows member, a rod attached to said latter closing member and extending outwardly through an aperture in said cover, said aperture communication to the inner part of said corrugated member, an adjustable member fitted in the aperture in said cover, a compression spring between said adjustable member and said plate, said adjustable member having an aperture therein through which said rod extends, a second adjustable member carried by the rod and arranged to abut the inner side of the adjustable member carried by the cover, said plate being normally held against the base of said casing by said spring, and means for applying fluid pressure between said corrugated bellows member and the reciprocation of said rod between the before mentioned stops.

3. In pressure actuated mechanism for control of electric switches, the combination with a switch having a member movable to make or break a circuit'through the switch, of a casing, a bellows like member therein having one end secured to the cusing, the opposite end being closed and provi ing a chamber between the member and easing sealed to atmosphere, a cap for the casing having an aperture roviding atmospheric communication to the inner part of said bellows like member, an apertured plug therein in threaded relation with the 'cap, a coiled compression spring extending between the plug and closed end of the bellows, a rod secured to the closed end of the bellows member and extending through the aperture of the threaded plug, said plug providing a means for adjusting the tension of the spring, a member on the shaft adjustable longitudinally thereof and limiting the extent of movement of the rod on compression of the bellows member whereby the switch mechanism is relieved from excess pressure, said rod being attached to the movable switch member.

4. In mechanism for controlling an electric circuit in combination with a switch having a member movable to make or break the circuit, of ap aratus for causing movement of the mem comprising a rod connected with the movable member, a bellows like member expansible or'contractible by variation in ressure, said rod being connected with t c said member, a casin enclosing the bellows member and providing providing atmospheric said plate for causing a. chamber between the member and the Wall of the casing, a cap member -for the casing through which the shaft extends, a plug threaded therein having a many sided central aperture, a nut threaded on the rod, the plug and nut having the same pitch and number of threads per inch, the nut having a many sided portion extending into the aperture of the plug whereby turning of 10 the plug turns the nut to like'extent, said nut having a flange normally spaced from the plug pei'n'iitting limited movementof the rod by contraction of the bellows member, and a spring extending between the plug and base of the bellows member adjustable in tension by the turning of the plug.

In testimony whereof, I sign this specificat-ion.

JAMES H. DENNEDY.

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