US2882916A

US2882916A - Force balance controller

Info

Publication number: US2882916A
Application number: US599809A
Authority: US
Inventors: Jr Robert E Ochs
Original assignee: Honeywell Inc
Current assignee: Honeywell Inc
Priority date: 1956-07-24
Filing date: 1956-07-24
Publication date: 1959-04-21
Anticipated expiration: 1976-04-21

Description

r1 |s" INVENTOR.

ROBERT E. OCHS JR April 21, 1959 R. E. OCHS, JR

FORCE BALANCE CONTROLLER Filed July 24, 1956 United States Patent FORCE BALANCE CONTROLLER Robert E. Ochs, Jr., Oreland, Pa., assignor to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn., a corporation of Delaware Application July 24, 1956, Serial No. 599,809

8 Claims. (Cl. 137-82) The general object of the present invention is to provide a flexible pivot on which a beam may be tilted in response to forces tending to raise one or the other of the beams ends while the remaining beam end is moved downward.

A more specific object of the present invention is to provide the aforementioned flexible pivot with a novel span adjusting means.

A still more specific object of the invention is to provide a span adjusting means that will apply regulatable amounts of tensile force to a flexible pivot to enable the gradient of the pivot to be changed.

In the desirable form of the invention illustrated by way of example, a first beam end is subjected to an uprising force by an input diaphragm, an opposite end of the beam is subjected to an uprising force by a bellows and a flapper and a flapper nozzle cooperate to automatically regulate the pressure applied to the last mentioned end of the beam. In the desirable construction shown, the central portion of the beam is rigidly connected to a thin flexible metallic strip which in normal operation may well be approximately perpendicular to the central portion of the beam.

The lower end of said strip is anchored to a stationary support. The beam is supported by the aforementioned thin flexible vertical strip which normally tends to maintain said beam in a substantially horizontal position, and by each end of the beam normally tending to tilt the beam in a direction opposite to the tilting direction impressed on the other end of the beam.

A better understanding of the present invention may be had from the following detailed description when read in connection with the accompanying drawing, in which:

Fig. 1 of the drawing shows one type of a force balanced beam structure in which my novel span adjusting leaf spring apparatus may be employed; and

Fig. 2 shows a view taken along line 22 of Fig. 1.

Fig. 1 of the drawing includes a beam 1 shown in an approximately horizontal position, and supported by a thin, normally vertical, metallic strip 2. The beam 1 is shown rigidly connected to a central portion of the strip 2. The lower end portion 3 of the strip 2 is anchored to the wall formed in a vertical slotted channel 4. The upper end of the vertical strip member 2 is connected to a coil spring 5' which has its upper end connected to a threaded screw element 6. The latter 2 extends through and is threadedly supported in a vertical internal screw threaded stationary supporting element 7. Rotation of the screw 6 in one direction will cause it to be moved upward and rotation of 6 in the opposite direction will cause it to be moved in a downward direction.

This upward or downward movement will cause the lower grooved out flange portions 8, 9 which are integral with the lower end of the screw 6 to also be rotated in the same manner. If this rotation is causing the screw shaft 6 to move in an upward direction the lower flange portion 9 will then apply a force in an upward direction to the lower portion of the bearing member 11. This upward force will be transmitted through the lower bearing member 11 to the lower surface of the grooved out keyed plate 12. This action Will cause the

cylindrical keys

13 and 14 to drive the plate 12 in an upward direction in the

slots

15 and 16 of the stationary member 7. As this latter action occurs it will cause the wire connections 17 and 18, which are fixedly attached to the underside of the plate 12, to apply a force in an upward direction at the connection 19 to the upper end of the spring 5.

When the screw 6 is rotated in a direction to make its lower portion 8 move in a downward direction it can readily be seen that the bearing member 21 and the key plate 12 will likewise be moved in a downward direction to lessen the tensile force on 17, 18, and spring 5.

It should be noted that since the plate 12 is prevented from turning by the

keys

13 and 14 riding in the

slots

15, 16, the aforementioned increase or decrease in tensile force is applied to the end of the spring 5 in a non-rotatable vertical direction. It can also readily be seen from Fig. 3 of the drawing that the aforementioned lower flanged portion 9 is a ring-shaped plate which is welded at its inner diametral surface to the lower end of the screw 6 after it has been positioned as shown against its associated bearing member 11.

In Fig. l, the end 22 of the beam 1 is shown connected by a depending bar 23 to the central portion of an input diaphragm 24. The latter forms a flexible upper wall of a diaphragm chamber 25. This chamber 25 is connected to a fluid 26 that is representative of the magnitude of a variable control pressure. The opposite end 27 of the beam 1 is connected to the movable upper end of a bellows element 28. As shown, the lower end 29 of the element 28 is stationary and closed except for a bottom wall port 31. The latter is connected by a conduit 32 to a vertical, upwardly extending tubular element 33. The tubular element 33 has an upper outlet port 34 normally discharging a variable jet of air under pressure against the underside of an approximately hori zontal flapper element 35. The latter has one end connected to and extending horizontally away from the adjacent end of the beam 1. The member 33 has a restricted lower end portion 36 receiving air 37 under pressure from an air supply conduit 38. Also connected to this tubular element 33 is a transmitting conduit 39. This conduit is used to transmit to a remotely located receiving instrument, e. g., a pressure indicating or controlling apparatus, any changes in pressure that take place in this chamber due to the displacement of the flapper 35.

In the normal operation of the apparatus shown in the drawing, an increase in the input pressure 26 transmitted to the diaphragm chamber causes the beam 1 to tilt in the direction to raise the left end 22 of the beam 1 while lowering the opposite beam end 27. The variable pressure transmitted to or away from the bellows 28 through the opening 31 in the normally stationary bottom wall 29 of the element 28 by the conduit 32, increases or diminishes as the flapper 35 is moved toward and away from the nozzle 34.

In the contemplated normal operation of the apparatus illustrated, an increase or decrease in the pressure acting on the underside of the diaphragm 24 results in an up or down movement of the beam end 22. As the diaphragm 24 moves the beam end 22 up or down, the beam end 27 tends to compress the bellows 28, or permits the latter to expand, with the result that the flapper 35 tends to move respectively toward or away from the nozzle 34. When the flapper 35 moves downward toward the nozzle 34, the pressure in the tubular element 33 increases as does the pressure in the bellows 28. The pressure increase in the bellows 28 tends to raise the beam end 27 and to lower the beam end 22 and thereby decrease the pressure impressed on the flapper member 35 by the element 33. In practice the increase in pressure then acting upward on the diaphragm 24, is neutralized in part by the increase in the pressure in the nozzle element 33.

In general, any increase in the input pressure impressed on the diaphragm 24 causes the beam end 22 to move and increase the pressure in nozzle element 34. In this way the input pressure 26 causes the flapper valve and bellows to transmit to the beam 1 a feedback force that acts to return the beam to a balanced position. The spring gradient of the strip 2 plus the aforementioned balancing force thus acts to balance out the input force impressed on the beam 1 by the magnitude of the control pressure 26. When the coil spring 5 is adjusted in an upward direction by rotating 6 in support 7 the coil spring 5 will be caused to carry a larger tensile load and the gradient of leaf spring 2 will be increased. When such an upward adjustment of spring 5 takes place it can thus be seen that a larger input pressure 26 acting on the diaphragm 24 and member 23 will be required to deflect the beam to the same extent as before; thus, the span is increased through the use of the tensile force applied to the upper end of a variable gradient strip 2. Likewise, when the tensile force on the coil spring 5 is reduced by rotating the screw element in a downward direction it will be readily apparent from the aforementioned remarks that the gradient of the strip 2 will be reduced and the beam will thus require a much smaller pressure 26 to deflect it to the same extent as before. One of the significant benefits derived from the span adjusting technique disclosed in this application is that such an adjustment may be accomplished without incurring any undesirable change in the zero position o the instrument.

A change in the tensile force thus causes a change in the moment required to cause a predetermined angular deflection of the beam. In other words, the change in the tensile force and the resultant gradient change thus causes a change in the deflection of the leaf spring 2.

As will be apparent, however, the apparatus shown is characterized by its inherent simplicity and effectiveness. While each end of the beam 1 must move both horizontally and vertically, the required movements may be so small as to be practically insignificant in magnitude.

The present invention provides a novel span adjusting means that alters the tensile force and the gradient of a strip member that pivotally supports a beam. Furthermore, the adjustment of the span adjusting means enables the operator to increase or decrease the magnitude of the feedback force that must be overcome by an input force applied to the beam in order that a predeterminedtilt of the beam may be effected by such an input force.

What is claimed is:

1. A beam pivoted to oscillate about an intermediate portion of the beam length, said beam being comprised of a pivot of a leaf spring configuration with an end fixedly attached to a first stationary member and its opposite end fixedly connected by means of a resilient member to a second stationary member, means engaging a portion of said beam at one side of the said intermediate beam portion, means engaging a second beam portion at the opposite side of said intermediate beam portion, said beam portions being transverse to the beam length and each connected to a separate flexible chamber and each having an inlet for the inflow of fluid into its associated chamber, a flapper element connected to and extend ing away from the second beam portion, and means for passing pressure fluid into one end of a conduit adjacent said flapper element and for passing pressure fluid out of said conduit into engagement with said flapper element and into said chamber that is adjacent said second beam end.

2. A beam as specified in claim 1 and including a mechanically adjusted means for varying the tensile force that said resilient means can apply to said opposite end portion of said leaf spring.

3. A beam as specified in claim 2 wherein said mechanical adjusted means is comprised of a threaded connection between said second stationary member and said resilient means.

4. A beam pivoted to oscillate about a deflectable leaf spring positioned intermediate the beam ends, means acting on one end of said beam in a direction tending to tilt the beam in a direction transverse to the length of the beam, means acting on the second end of said beam in a direction tending to tilt said beam in a direction approximately parallel to the first mentioned direction, a flapper element connected to and extending away from the second end of said beam and in the general direction of the beam length, a stationary means for discharging a fluid jet against one side of said flapper element, means for varying the distance between said stationary means and the adjacent side of said beam including said means acting on one end of said beam and means for varying the pressure impressed on said beam including said second means acting on the second end of the beam.

5. A beam pivoted to oscillate about a portion of said beam intermediate the ends of said beam, said bean being comprised of a pivot of a leaf spring configuration with one end fixedly attached to a stationary member, an intermediate portion attached to said beam and a remaining end mounted by means of an adjustable spring tensioning means to a stationary member, means acting on one end portion of said beam tending to tilt said end portion in one direction and means acting on the opposite end portion of said beam tending to tilt the latter in a direction opposite to: the first mentioned direction, a flapper extending away from an adjacent end of said beam, a conduit transverse to said flapper and having an outlet end adjacent and transverse to the end of the flapper, and means for continuously passing fluid into said conduit and thence out of the outlet end of the conduit and into engagement with said flapper.

6. A substantially horizontal beam, a flexible vertical element extending through and being attached to a central portion of said beam, a stationary member in which the lower end of said element is fixedly attached, an adjustable resilient means connected to the upper portion of said flexible element and being operably connected to apply a tensile force to said element and control elements supported by elements suspended on each of the end portions of said beam and subjecting said beam ends to vertical forces adapted to longitudinally tilt said beam about said flexible element.

7. A means for adjusting the span of a force balance apparatus comprising, an elongated leaf spring, a beam pivoted in a see-saw fashion on a central portion of said leaf spring pivot, said pivot having one of its elongated ends fixedly connected to a stationary member and its opposite end adjustably mounted in a tensile force generating means and a mechanically actuated means operably connected to said force generating means for causing said generating means to change the magnitude of the tensile force that it is applying to the said end of said leaf spring.

8. A span adjusting apparatus for use in a force balance system comprising, a cantilever leaf spring fixedly attached at its lower end to a stationary member and protruding upwardly from said member, a horizontally positioned beam pivoted to a portion of said leaf spring, a fluid pressure flapper-nozzle apparatus positioned relative to said beam to be adjusted thereby, a first pressure responsive means connected to said beam and to the nozzle of said flapper-nozzle apparatus to apply a force to said beam in accordance with the back pressure of said nozzle, a force producing means connected to said beam to provide an input force thereto for altering the amount of fluid bled from said flapper-nozzle apparatus, said force producing means comprising a pressure responsive diaphragm means coupled to said beam and an adjustable resilient means connected at its lower end to the upper end of said leaf spring for altering the amount of tensile force that is applied to the leaf spring.

No references cited.