US2945656A - Constant support hangers - Google Patents

Description

y 1960 P. c. SHERBURNE 2,945,656

CONSTANT SUPPORT HANGERS Filed June 12, 1957 5 Sheets-Sheet 1 IN VEN TOR.

PHILIP 0. SHERBURNE I ATTORNE July 19, 1960 Filed June 12, 1957 P. c. SHERBURNE CONSTANT SUPPORT HANGERS 5 Sheets-Sheet 2 I l PHILIP c.

INVENTOR.

SHERBURNE y 1960 P. c. SHERBURNE 2,945,656

CONSTANT SUPPORT HANGERS Filed June 12, 1957 5 Sheets-Sheet 3 INVENTOR.

PHILIP G. SHERBURNE July 19, 1960 P. c. SHERBURNE 2,945,656

CONSTANT SUPPORT HANGERS Filed June 12, 195'! 5 Sheets-Sheet 4 I ll 50 k 7 5a 56 H 7 6O 9/ H i g 4 I I H 70 \86 '76 a? FIG. 5

INVENTOR.

I PHILIP O. SHERBURNE July 19, 1960 P. c. SHERBURNE CONSTANT SUPPORT HANGERS Fi led June 12, 1957 5 Sheets-Sheet 5 INVENTOR.

PHILIP c. SHERBURNE flaw/6% ATTORN Y n d States CONSTANT SUPPORT HANGERS Philip C. Sherburne, Rumford, R.I., assignor to Grinnell Corporation, Providence, R.I., a corporation of Delaware Filed June 12, 1957, Ser. No. 665,329

Claims. (11. 248-58) fluid, such changes in condition of the fluid actuating a mechanism for changing the length of the hanger to compensate for the changes in force. Another object is to provide such a constant support hanger in which the body of fluid supports at least a part of the load.

Another object is to provide a hanger of the abovementioned type in whichchanges in force appliedby the load cause relative movement between a supported member supporting the load and an anchor member, in which such relative movement causes the actuation of mechanism for changing the length of the hange'r to compensate for the changes in force and in which such relative movement is provided by a body of fluid which is located in a chamber having a wall which is movable with the supported member and with respect to an opposite wall of the chamber in response to such changes in force.

Another object is to provide a constant support hanger utilizing a motor for changing the length of the hanger to maintain constant support and having an improved switching mechanism which responds to slight apparent changes in load caused by movements of the load to operate the motor and change the length of the hanger to compensate for the movements. Another object is to provide such a constant support hanger utilizing such a motor and having aswitching mechanism operatedby fluid pressure derived from a fluid cell arranged so that the load produces a pressure in the fluid therein.

Another object is to provide constant support hanger utilizing a motor to change the length of the hanger to maintain constant support and having a fluid pressure operated switching mechanism for controlling the operation of the motor in reponse to movements of the load being supported. n a

Another object is to provide a constant support hanger utilizing a rnotor to change the length of the hanger to maintain constant support and having a fluid pressure operated switchingmechanismfor controlling the operation of the motor, said mechanism including a fluid-filled cell which supports at least part of the load and in which the fluid pressure varies with apparent' changes in -load caused by load movement, and said mechanism also including a switch responsive to such pressure variations.

Another object is to provide such a motor operated constant support hanger havingsa fluid pressure operated switching mechanism for controlling the operation of the motor, such mechanism including a hydraulic load cell V in which the pressure varies with apparent changes in load caused by load movement, said mechanism also including a switch responsive to such pressure variations, and said mechanism further including means -for adjusting the switch to respond to such variation between different pressures.

Other objects will appear hereinafter. The'accompanying. drawings show and the following specification describes preferred embodiments of the present invention. They are merely illustrative of the invention which is not intended to be limited thereto.

In the accompanying drawings:'

Figure 1 is a front elevation view of an embodiment of the present invention showing the device supporting a suspended load;

Figure 2 is a side elevation view of the arrangement shown in Fig. 1;

Ffigure 3 is a top view of the arrangement shown in Figure 4 is a view taken on line 44 of Fig. 1;

Figure 5 is a view taken on line 55 of Fig. 4; and

Figure 6 is an enlarged diagrammatic View of a switching arrangement in accordance with the invention.

Referring now to Figs. '1 to 5 of the drawings, the load to be supported is designated by the numeral 10 and is shown as a section (see Fig. 2) of a horizontally extending pipe. For example, this section might be in the main steam line of an electric power generating station carrying steam from the boiler to the turbine. Such a pipe section'is typical of loads which require support and at the same time must be free to move vertically within a limited range. Thus, vertically extending portions (not shown) of the pipe 10 or of other pipes connected to this section 10 would cause it to move vertically when the lengths of such vertical portions change with changes in temperature.

The loads with which thisinvention is primarily concerned are those like the piping referred to which are connected to fixed structure at one or more points remote the hanger by the weight of the'load because the con-- nections to fixed structure at the points remote from the hanger take over the support of some of the weight.

Similarly if the movement of the point of hanger attachment is vertically downward the force exerted on the hanger will actually exceed the weight of the load.

In otherwords typical loads for hangers of the present invention exert varying downward forces on the hangers even through the weights of the loads remain the same, and the change in force is in accordance with the vertical movement of the load from that position where the force just equals the load. For example if the load moves vertically upward from the location where the force 'on the hanger just equals the load weight the force on the hanger decreases progressively, and conversely if the load moves downward from such location the force increases electric motor 12 is mounted on a frame base 14 which is located above the pipesection 10 to be supported and which is itself secured to building frame members 15 by conventional nut and bolt assemblies 16. The shaft 17 of the motor 12 is disposed with its longitudinal axis sub-' sta'ntially horizontal and is provided with a worm gear 13' Patented July 19, teen which meshes with a worm wheel 20. This worm wheel is disposed with its axis substantially vertical and has a central threaded opening 22 (see 'Fig. The worm wheel is mounted on an annular thrust bearing 24 located around an opening 26 in the frame base 14 and is supported by a hub 28 welded on this base. A long threaded shaft 30 extends through the hub opening 26 and is threaded through the opening 22 in the worm wheel 20. The upper end of this shaft is provided witha stop member 32 to prevent the shaft from being threaded completely through the opening 22, and the lower end of this shaft is provided with a' horizontally disposed plate 34. This plate 34 forms the upper member of a hydraulic load cell which has a corresponding lower member in the form of a similar plate 36 to which there is secured the upper end of a central depending rod 38. The load is suitably connected to the lower end of this rod 38. Between the upper and lower members 34 and 36 of the hydraulic loadcell are located three additional plates 42, 44 and 46. Bolts 48 which have heads 49 engaging the upper plate.34, pass slidably down through the plates 42 and 44 and are threaded into the plate 46. Similiarly bolts 50 which have heads 51 engaging the lower plate 36 pass slidably up through the plates 44 and 46 and are threaded into the plate 42. The plate 42 is provided on its lower face 43 with a central recess 52 having a bottom 54, an annular shoulder 56 and sidewalls 58. The shoulder is provided with an annular gasket 60, and a flexible metal diaphragm 62 which extends across the recess and has its periphery resting on the gasket. The diaphragm, gasket, shoulder and the bottom of the recess thus define a sealed chamber 63. located on the side of the diaphragm 62 opposite this chamber is an annular ring 64 disposed so as to be opposite the inner edge of theshoulder 56. This annular ring is held in place by apiston 66 which has its upper end 67 of reduced diameter to receive this ring. The surface of this upper end. of the pistonrests against the lower face of the diaphragm 62 as does the corresponding upper surface of the ring 64. The piston 66 is slidably located in a central opening 68 in themember 44 and its lower end 69 extends .below the lower side of this member 44 and engages the upper side of the member 46 when its upper end 67 iszin engagement with the diaphragm 62. The member 44 is secured to member 42 by bolts 70 and has an upstanding annular lip 71 which accommodates the ring 64 and is received into the recess 52. The chamber 63 is filled with a fluid 72, for example, oil.

The general arrangement above described constitutes a hydraulic load cell in which the pressure of the fluid 72 changes with changes in the force exerted downwardly by the load on the rod 38, such pressure changes being the result of slight flexing of the diaphragm 62 by the changes in force. In eflect the change in force causes a slight movement of plate 42 with respect to the piston 66 which causes the slight flexing of the diaphragm 62. Oil 72 is also located in a passage 74 leading from the chamber to an opening 75 in the side of the member 42.

A switching mechanism designated generally at 76 is actuated by changes in the pressure of the oil 72. This mechanism includes a frame plate 78 mounted on the member 42, for example by screws 80, and on this plate are mounted two switches 82 and 84 having plunger ele ments 86 and 88, respectively, extending therefrom. A Bourdon type tube 89 is connected to the opening 75 at the end of the passage 74, and curves around so that its moving end 90 engages the plungers 86 and 88. This moving end 90 responds to changes in the oil pressure to actuate the switches 86 and 88. If the pipe section 10 is rising, for example because of a change in the temperature of the piping which changes the length of risers connected to the section 10, thereby tending to elevate this section, such upward movement of the section 10 relieves some of the downward force exerted on the rod 38 and hence on oil 72 throughplate 36, bolts 50 and plate 42. As a result the oil pressure decreases, and the end of the Bourdon tube moves to the left (as seen in Fig. 5), allowing the spring loaded plungers 86 and 88 to also move,

to the left. One of these switches 82 is arranged so that after a predetermined amount of such plunger movement switch 82 is closed and a circuit is completed which turns on the motor and causes it to rotate in a direction to lift the threaded shaft or screw 30; This upward lifting of the screw 30 exerts an upward force on the piston 66 through plate 34, bolts 48'andplate 46 and increases the oil, pressure so that the movable end of the Bourdon tube moves back to the right. Motor operation continues until the oil pressure increases enough to move the end of the Bourdon tube to the right a predetermined distance which again openstheswitch 82. This stops the operation of the motor which stops lifting the screw 30. The load has moved up to a new position and the hanger has operated to restore the lifting force which existed prior to movement of the load and as measured by the pressure of the oil 72. If'the load continues to rise above this new position the above operation-is repeated.

If. the piping system cools down and the pipe section 10 moves downwardly, this has the effect of increasing the oil pressure in the load cell which moves the end of the Bourdon tube to the right as seen in Fig. 5. After a predetermined movement of this end of the Bourbon tube the switch 84 is closed which completes a circuit to operate the electric motor 12 in a direction moving the screw 30 down. Such movement of the screw relieves the pressure in the cell and the end of the Bourdon tube moves back to the left until the switch 84 is again opened when the force on the fluid existing prior to the downward movement of the load has been restored, thereby stopping the operation of themotor.

Thus it will be seen that the device is arranged to respond to pressure fluctuations caused by pipe movements and to maintain substantially constant supporting elfort on the pipe regardless of its vertical position. More particularly the motor operates intermittently as the load moves. When upward movement of the load decreases the oil pressure to a predetermined lower limit motor operation commences and the support for the load is lifted until the oil pressure has increased to a first predetermined intermediate limit whereupon loadlifting motor operation terminates, and when downward movement of the load increases the oil pressure to a predetermined upper limit opposite motor operation commences and the support for the load is lowered until the oil pressure has decreased to a second predeterminedintermediatelimit whereupon load-lowering motor operation terminates.

The maximum variation in supporting effort with such an arrangement is the dilference between the actual weight of the load and the lifting force exerted by the hanger which differs the most from this load. Such lifting force which dilfers the most would be the lifting force at either the upper or lower predetermined oil pressure limit. I

The speed at which the motor 12 moves the screw 30 must exceed the speed at which the pipe moves vertically so that the pressure changes produced by such pipe movement may be nullified as soon as they have reached proportions which can reasonably be detected.

As shown. in Figs. 5 and 6 the movable end 90 of the Bourdon tube is'biasecl to the left by an adjustable spring 91. By increasing or decreasing the tension on this spring the pressure which is-required to move the end of the Bourdon tube far enough tooperate the switches 82 and 84 can be varied. The result is that the load which the hanger will support is also varied. A pointer 92 is provided on the end 90 of the Bourdon tube and in conjunction with a scale 94 serves as an indication of the load forwhich the hanger is set.

Figure 6 is a somewhat diagrammatic enlarged view of the switching mechanism shown in Fig. 5 and illustrates one switching mechanism arrangement which pro- 96 carries a connection 97 which extends through and is movable along a longitudinal slot 103 in the cylinder 98. This connection is for one end of a tension spring 104 the other end of which is connected to the end 105 of a lever 106 pivoted at .107 on a bracket .108. The lever 106, spring 104 and bracket 108 are so arranged that as this piston 96 moves to the left in its cylinder 98 the movement of the spring connection 97 across the line A snaps the lever 106 over against an adjustable stop 1'10, and thereafter movement of the piston 96 back to the'right until the point 97 again crosses the line B causes the'lever to fly back against the adjustable stop 112. The lever 106 will always be hearing against one-or the other of these two stops 110m 112, and when it is bearing against either one of them the spring must move across the line .A or B before the lever will move over to bear against the other.

Consider now the operation of this switch 82. Assume that the load begins to move upwardly, reducing the pressure of the oil 72 in the load cell. This in turn reduces the pressure in the Bourdon tube and the end 89 .of this tube moves to the left. During the initial part of this movement the spring 104 is holding'the lever 106 against the stop.112 (see Fig. 6). After the spring connection 97 has moved from position C to position D as a result of the spring 100 causing the plunger '86 to follow the retreating end of the Bourdon tube, the

lever 106 snaps over against the stop 110. This stop 1'10 and the lever .106 constitute a switch. The electrical leads 1.14 and 12161510!!! the stop and lever, respectively, lead to a source of electricity and to the motor 12. Thus after the end 90 of the Bourdon tube has moved through a distance equal to that between the positions Cand D the motor is turned on to lift the screw 30 upwards and increase the pressure of the oil 72. Such a pressure increase causes the end 90 of the Bourdon tube to move toward the right; but it is not until the connection 97 moves back to the right beyond position E that the lever will be returnedby the spring 104 to the stop 112. When it so returns the switch 106- 110 is opened and the motor ceases to lift the rod 30.

The switch 84 is; substantially identical to the switch 82 but is arranged to close the switch 118-120 only after the end of the Bourdon tube has moved to the right through the distance F--G after the switch 106-- III!) has opened. When the switch 84 is closed it closes a circuit to the mot-or which operates the motor to move the threaded rod 30 downwardly. The motor is not shut off until the Bourdon tube moves back to the left far enough for connection 125 to reach position H.

The stops 110, 112, 120 and 122 are made adjustable so that the distances through which the end of the Bourdon tube must move before the snap action switches are thrown can be varied. The plungers 86 and 88 are made adjustable in pistons 96 and 124 so that the delay between the opening of switch 82 (which drives the motor one way) and the closing of switch 84 (which drives the motor the other way) can be varied. This delay must not be too small or a change of oil pressuredue to operation of the motor in one direction might cause the motor to be turned on to move the load in the opposite direction. For example, it will be seen that when the end 90 of the Bourdon tube moves far enough to the right to open the switch 82 a further that the additional distance through which the end 90' need move to the right after the opening of switch 82 before the closing of switch 84 could be much smaller than F--G, for example I-G. In other Words the supported. Vertical movement of screw 30 changes the eflEective length of the hanger between the anchor member14 and the load 10 so that screw 30 and nut 20 comprise means for so changing the length of the hanger, and the motor 12 comprises means for actuating the means for changing the hanger length. Member ,42 forms a wall of the hydraulic fluid chamber containing the body of fluid 72 and is connected to and movable with supported-member 36. Piston 66 and plate 46 on the otherhand, are movable with the vertically movable screw 30 and consequently are rigidly supported by the anchor plate 14 when the screw 30 is deactuated and hence stationary. The upper part-of piston 66 forms a wall of the hydraulic fluid chamber with respect to whichmember 42 is movable in response to changes in 'force applied by the load. The hydraulic cell as arranged in the drawings comprises hydraulic fluid means for controlling the operation of the motor in response to changes in force applied to supported member 36 by changes. in vertical location of the load, and switch 76 comprisesa fluid operated switch which controls the operation of the motor and which in turn is actuated by changes in the condition of fluid 72 in response to changes in force applied by the'load. The fluid cell permits slight relative movement of the supported member with respect to the anchor member, which movement is eifective tochange the pressure on the fluid and actuate the fluid-operated switch. a

-I claim:

' 1. A constant support hanger comprising a supported hanger between the load and said anchor means, meansfor actuating said length adjusting means, a body of hydraulic fluid to which at least a portion of said force is adapted to be applied, means responsive to changes in said force applied to said supported member by said load for changing theforce applied to said body of hydraulic fluid, said body of hydraulic fluid being responsive to said changes in force exerted thereon to actuate said means for actuating said length adjusting means, to thereby automatically adjust the eifective length ofsaid hanger between the load and anchor means and to compensate for said changes in force applied by said ioadl 2. A hanger according to claim 1, wherein said means I for actuating said length adjusting means comprises a motor and said body of hydraulic fluid includes a hydraulic fluid pressure operated switch for controlling the operation 0t said motor, the pressure of said hydraulic fluid being varied automatically in response to said changes in force and said switch being operated in response to said pressure variations.

- 3. A hanger according to claim 2 wherein said hydraulic fluid pressure operated switch comprises a Bourdon tube.

4. A constant support hanger according to claim 1, wherein said body of hydraulic fluid is located in a chamher having a wall which isconnected to and movable with said supported member in response to said changes in force, and another opposite wall with respect to which said first mentioned wall is movable in response to said changes in force, whereby said changes in force are applied to said hydraulic fluid to change the pressure there--,

7 of, said means for actuating said length adjusting means being responsive to said changes in pressure to actuate said length adjustingm'eans to'automatically adjust'thei which is connected to and movable with said supported member in response to said changesin forceand another opposite wall which is rigidly supported by said anchor means at least when said length adjusting means is deactivated, whereby said changes in force applied to the supported member and henceto said hydrauliefiuid' by said load change the pressure of said hydraulicfluid in said chamber, said means for actuating said length adjusting means being responsive to said changes in pressure to actuate said length adjusting means to automatically adjust the length of the hanger. to compensate for said changes in force.

6. A constant support hanger comprising a supporting member to which a force is adapted to be applied by a load, anchor'means for-supporting said supporting member, means for adjusting the effective length of said hanger between the load and said anchor means, means for actuating said length adjusting means, a first body of liquid contained in a first expansible chamber, means connecting said load supporting member to said first chamber for transmitting the force of said load to said first chamber to change the volume thereof, a second smaller body of liquid. communicating with said first body and contained in a second expansible chamber, whereby changes in the volume of said first chamber produce changes in volume of said second chamber, means responsive to changes in the volume of said second chamber to actuate said means for actuating said length adjusting means, thereby automatically adjusting the eflective length of said hanger between the load and anchor means and compensating for said changes in force applied by said load.

7. A constant support hanger comprising a supporting member to which a force is adapted to be applied in one direction by a load, an anchor member for supporting said supporting member, means for adjusting the effective length of said hanger between the load and said anchor member, means for actuating said length. adjusting means, a fluid pressure chamber having one movable wall which is connected to said supporting member and movable therewith in response to changes in force applied to the supporting member by the load and which has an area over which fluid pressure in said chamber is effective to resist said movement, said fluid pressure chamber having a second movable wall which is movable With respect to one of said members and which has a smaller area over which fluid pressure in said chamber is effective to move said second movable wall with respect to said one member, means responsive to movement' of 'said second movable wall with respect to said one member in response to changes in said fluid pressure caused by changes in said force for actuating 831411168115 for actuating said length adjusting means, whereby-the eifectivelengthof thehanger between the-load and said anchor means is automatically adjustedto compensate- 'for said changes in force applied by said load.

8. A constant support hanger comprising a supporting member to which a force is adapted to be applied in one direction-by a load, an anchor member for supporting said supporting member, means for adjusting the eifect-ive length of said hanger between the loadand said anchor member, means for'actuating saidlength adjusting means,

afirst fluid: pressure chamber having one wall which'is' connected to said supporting member and movable in said' direction in response to changes in the force applied to the supporting member by the load and having a second opposite wall with respect to which said first mentioned wall and said supported member are movable in response to said changes in force, a second fluid pressure chamber in communication with said first chamber and having a' wall which is movable in a predetermined direction, a

body of fluid contained in said chambers and maintained under pressure when said force is applied to the supporting member by the load, said first chamber movable Wall having an area over which said fluid pressure is efiective to resist movement of said first chamber movable wall in said first mentioned direction, said second chamber movable wall having an area over which said fluid pressure is efiective to move said second chamber movable wall in said second mentioned direction and which is smaller than the area of said first chamber movablewall,

means responsive to movement of said second chamber movable wall in response to changes in pressure in said fluid caused by changes in said force for actuating said means for actuating said length adjusting means, whereby the effective length of the hanger between the load and said anchor means is automatically adjusted to compensate for said changes in force applied by said load.

9. A hanger according to claim 7 including means for exerting force on said second wall which opposes said movement of said second movable wall' with respect to said one member, and means for adjusting the magnitude of the force exertedby said force exerting means, Whereby the means responsive to said second wall movement may be caused to actuate said length adjusting actuating means at different fluid pressure in said chamber.

10. A hanger according to claim 9 wherein said force exerting means is a spring, and said force magnitude adjusting-means is a member adapted to change deflection of the spring.

References Cited in the file of this patent UNITED STATES PATENTS

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