US2981273A - Electro-hydraulic control device - Google Patents

Description

April 25, 1961 B. CALLENDER r-:rAL 2,981,273

ELECTRO-HYDRAULIC CONTROL DEVICE 3 Sheets-Sheet 1 Filed June 24, 1958 lll JMA @y MJ @im PI 25, 1961 B. L. CALLENDER x-:rAL 2,981,273

ELECTRO-HYDRAULIC CONTROL DEVICE Filed June 24, 1958 3 SlleebS-Sheet 5 April 25, 1961 B. .Y CALLENDER ETAL 2,981,273

ELECTRO-HYDRAULIC CONTROL DEVICE 5 Sheets-Sheet 2 Filed June 24, 1958 m 70eme? G. )570 United States This invention relates ,to an electro-hydraulic control device which incorporates the well known hydraulic jet pipe.

In the United States patent to `Holzbock 2,814,183, there is disclosed an electro-hydraulic relay having a hydraulic4 jet pipe adapted for movement which results in creation of a pressure differential upon a piston to cause movement of the piston and controlled device connected thereto. Movement of the jet pipe is caused by an electromagnetic means responsive to an electric signal which is initiated whenl regulation of the controlled device is required.

p The present invention in general, is similar in structure and operating principle to the device of the above identified patent, however, it incorporates certain new and novel features providing a control device which represents atent an improvement over like devices of the prior art. More particularly, the present invention teaches the use of a iiexible jet pipe, of differing forms, each of which are adapted to provide more uniform and precise performance under a wide range of operating conditions. In addition, the present invention is characterized by further details of structure which contribute to an improved control device, such as the complete enclosure of all components making up the control device, and the use of means to dampen oil movement caused by vibrations and other disturbing inuences, to prevent erratic motion of certain movable parts of the control device.

The main object of this invention is to provide an improved electro-hydraulic control device having a hydraulic jet pipe.

A more specific object of this invention is to provide an electro-hydraulic control device having a jet pipe which assures more uniform and precise performance under a wide range of operating conditions.

Another specific object is to provide an electrohydraulic control device wherein all the components are completely enclosed.

Still another object of the invention is to provide an electro-hydraulic control device having means to dampen oil movement to thus prevent erratic motion of certain movable parts of the control device.

These and further objects and features of the invention will become more apparent from the following description and accompanying drawings wherein:

Fig. 1 is a section view of a control device embodying the principles of the invention;

Fig. 2 is a view partly broken away and as seen from line 2 2 in Fig. l;

Fig. 3 is a partial section view of a control device similar to that shown in Fig. l, but wherein a different type of jet pipe arrangement is used;

Fig. 4 is an enlarged section view of a portion of the jet pipe used in the Fig. 3 control device;

Fig. 5 is a side view of a modified type of jet pipe arrangement for use in the device of Fig. l;

Fig. 6 is a front view of the same;

Fig. 7 is a side view of another modied type of jet pipe arrangement for use in the device of' Fig. 1; and Fig. 8 is a front view of the same.

Referring now to the drawings, the numeral 10 identi- 2,98L273 Patented Apr. 25, 1961 fies a control device embodying the principles of the invention, which includes a housing section 12, and an upper housing section 14, said housing sections being arranged for intertting in liquid 4tight manner. A gasket 16 is positioned between the lower and upper sections 12 and 14 respectively. A Semicircular pan or bulkhead 18 is secured to the lower housing section 12, and is arranged to support a liquid pump 20 positioned within the upper housing section 14, and an electric motor 22 positioned in the lower housing section 12 and arranged to operate the pump Ztl.` A pump intake pipe 24 extends from the pump 20, and has an open end located within the lower housing section 12. Also secured to the pan 18, is a terminal block 26 which serves as a junction block between the power and signalv lines coming into the control device and the respective elements with which they are electrically associated, 4and will more clearly appear hereinafter.

An opening 28, formed in the bottom of the lower..

housing section 12, is covered in liquid tight manner by a plate or ange 30. Supported upon the plate 30, is a cylinder 32, the upper end of which is enclosed by a cover plate 34, which is of elongated form and which overhangs the cylinder in disproportionate amounts as shown. .'Slidably arranged within the cylinder 32, is a double acting piston 36, which is aiiixed to a piston rod 38 extending upwardly through the cover plate 34, and downwardly through the ilange 30. A pair of bushings, or end caps 40, each containing a springless oil seal 42, are positioned to provide smooth, liquid-sealed movement of the piston rod 38 during ytravel thereof. Aliixed to the top surface ofthe upper bushing 40, is a sleeve 43, whichis in spaced relation to the piston rod 38, and which serves as a stop for a stroke limiting nut 45 threadably secured to the upper extremity of the piston rod 38. It will be seen that axial adjustment of the nut 45 may be used to limit downward movement of the pistod rod.

A distributor means, in the form of closely spaced receiver ports, or orilices 44 and 46, is formed in the cover plate 34, each orifice having a tapered and outwardly sloping passageway 48 and 50 respectively. Passageway 48 leads to and opens into the cyinder 32 in the region above the piston 36, while passageway 50 leadsto and opens into one end of a passageway 52 formed in the wall of cylinder 32, the other end of the passageway 52 being connected via an opening 54, with the region below the piston 36.

Secured to the top of cover plate 34, at one end thereof and extending upwardly therefrom, is a rectangular pillar or block 56 which has an L-shaped bracket 58 mounted upon its upper end. Aiixed to the underside of the bracket 58 are a pair of horizontally arranged metal tapes, or straps 60, which project beyond the upturned portion of the bracket, while a vertically arranged metal tape or strap 62 is affixed to the front or outer surface of the bracket, and projects downwardly between the straps 60. The other end of straps 60 and 62 are secured to a carrier means, or member 63 formed of a metal strip having a horizontally disposed arm 64 and a vertically disposed arm 66, said arms being arranged substantially at a right angle. As best seen in Fig. 1, the straps 60 and 62 are secured to the carrier member in the region of intersection of arms -64 and 66, to port, often referred to as a exure pivot.

Aliixed to the lower end of the arm, 66, is a nozzle, or jet piece 68 having a tapered, or conical passageway '70 terminating in an orifice 72, which is positioned a short distance above the distributor orices 44 and 46. Pivotal movement of the carrier member 63, will cause the jet piece oriiice 72 to move in a plane coincident with the plane of distributor orifices 44 and 46. A exible hose 74, preferably made of a plastic material such as `neohousing formed of a lower.

provide a pivotal sup-A prene, Ahas one end connected to the discharge side of the pump 20, and the other end connected to the nozzle piece 68, said hose being aixed at one point to the block 56 Iby a clamp, or bracket 76. In such manner, liquid, such as oil, is delivered under pressure from the pump 20 to the nozzle 68.

Secured to the top of the cover plate 34, at the end opposite that which supports the block 56, is an angle iron bracket, or support 78, having an electromotive means 80 arranged at lthe upper end. The electromotive means 80 includes a U-shaped housing 82 aixed to the bracket 78, a cylindrical permanent magnet 84 supported bythe housing 82, a pole piece 86 having a circular hole 88, and a moving coil assembly 90, which is secured to the end of arm 64. The coil assembly 90 includes a spool-like member 92, and a coil 94 carried by the member 92 in the region of an air gap defined by a portion of the periphery of the magnet 84 and the circular hole 88 of the pole piece 86. An adjusting screw 96, anchored upon the pole piece 86 may be used to regulate the maximum upward movement of the coil assembly 90. A pair of terminal posts 98 are provided for connecting the ends of fthe coil 94 with the appropriate terminals of the terminal block 26. Parts 82 and 86 are made of iron or steel; coil 94 is made of copper wire; and part 92 is made of a non-magnetic material. It will be seen that pivotal movement of the carrier member 63 about the exure pivot bears a delinite relation to the accompanying substantially axial movement of the coil assembly 90.

A helical sprin-g 100 is arranged to extend between the carrier 63 and the housing 82, one end of the spring being connected to a bracket 102 which is secured to the carrier arm 466, the other end of the spring being connected -to an adjusting screw 104 which is movable axially in a bracket assembly 106 ailixed to the housing 82, as best seen in Fig. 2. By regulation of the axial position of the adjusting screw 104, the tension of the spring 100 may be varied. l

A helical spring 108 is arran-ged to extend between the piston rod 38 and Ithe carrier arm 64, one end of the spring 108 being connected to the end of the rod 38, the other end of the spring being connected to a headed pin 110 which is supported for swivel movement in an expansion ring, or clip 112 having opposed ears (not shown) which are normally in engagement with the sides of a longitudinal slot 114 formed in the carrier arm 64. By squeezing the ring 112 lto move the ears closer together, the ring will be freely slidable in the slot 114, whereby thesetting of the spring 108 may be regulated to adjust piston stroke; when the desired adjustment is attained, release of squeezing pressure will permit the ears of the ring to tightly engage the sides of the slot 114, so lthat the adjusted setting is maintained.

VA rod 116 extends upwardly from a flange 118 forming part of the pump 20, and projects through the upper housing section 14. Fastening means, such as nut 119, may be used to threadably engage the rod 116, and to hold the housing sections 12 and 14 clamped tightly together. Removably affixed to the rod 116, and at a distance above the pump 20, is a circular plate 120, the peripheral edge of which is spaced a short distance from the adjacent inner surface of the upper housing section 14. The plate 120 serves as a dampening means to abate movement of the oil carried, or maintained, in the control device. A liquid supply plug 122 is arranged in the top surface of the upper housing section 14, while a liquid level sight gauge 124 is arranged in the side thereof.

The operation of the control device is Well known and similar to the principle of operation of the device of Patent 2,814,183. Assume that the piston rod 38 is connected to a valve (not shown) which is in a pipe, or line, wherein pressure is to be maintained at a given, or normal, value. Under normal pressure conditions in the line, the jet pipe orifice 72 will be equally spaced between distributor oriices 44 and 46, so that yjet Aoilpressure on '(5 jectives of the invention.-

each side of the piston 36 will be equal. An electrical signal generator associated with the pipe, will provide a given electrical current when the line pressure is normal, and an error signal when a change of pressure from the normal occurs. In the latter case, the electromotive means will be activated resulting in proportional movement of the jet pipe carrier 63 so that the jet pipe orifice 72 will be shifted, causing oil pressure upon the distributor orices 44 and 46 to be unequal. As a result, a pressure differential will be imposed upon the piston 36 and movement of the piston and the rod 38 will occur, which will provide the correction required in the valve attached to the piston rod 38. Such movement of the piston rod 38 will change the tension of spring 108, and as a result of the lforces acting upon the carrier 63 will be equalized, and the jet pipe orifice 72 will be restored to neutral position. Upon arrival of the jet pipe orifice to its neutral position, piston movement Will cease due to equalization of forces acting upon the piston.

It will be appreciated that the use of a flexible jet pipe in the control device of the invention reduces extraneous torque conditions being imposed upon the jet pipe carrier, such as are caused by friction forces and which are often associated with non-llexible jet pipes of the prior art.

The modified embodiment of the invention illustrated in Fig. 3, diiers mostly in the structure and arrangement of the jet pipe. In the description of the modified embodiment, all parts of which are substantially similar in form and function to those described above, will be identiiied by the same number.

An L-shaped bracket is affixed to the upper end of the pillar 56, which bracket secures the end of each of the straps 60 and 62 to form a llexure pivot for the carrier member 63. A hose coupling piece 132 is secured to the bracket 130, and is adapted to threadably receive a pipe fitting 134, to which one end of a pressure fluid supply tubing 136 is connected. The other end of the supply tubing 136, which may be made of metal, is connected to the liquid outlet of a pump '138, the latter being arranged for operation by a motor (not shown) A corrugated jet pipe 140, preferably made of a copper alloy, is secured at the upper end to the coupling piece 132, extends downwardly through a hole 142 formed in the bracket 130, and is affixed at the lower end to a nozzle, or jet piece 144. The corrugations of the jet pipe 140, may be either spiral, i.e., continuous, or individual, i.e., non-continuous. The nozzle piece 144 is slidably arranged in a bushing 146 affixed to the lower end of the carrier arm 66, and has a tapered, or conical, passageway 148 terminating in an oriiice 150. The latter is arranged in spaced relation to the distributor orices l44, and 46, whereby pressure iluid will be conveyed to the sides of the piston 36 in proportion to the response demands imposed upon the control device, as has been explained in connection with the 'first described embodiment.

A modified arrangement for attaching the end of the spring 108 to the carrier arm 64, comprises an upper plate 150 slidably arranged against the top surface of arm 64, a lower plate 152 slidably arranged against the bottom surface of arm 64, a pair of screws 154 which pass through the upper and lower plates 150 and 152, respectively, and extend through the carrier arm slot 114 and through spring type fastening means 156 forming part of the plate 152. The headed pin 110, to which the-spring 108 is aliixed is carried by the upper plate 152, said pin 110 extending through the arm slot 114. By moving the plate 150and 152 longitudinally in the slot 114, and tightening the screws 154 the setting of the spring 108 may be easily adjusted and securely maintained.

It will be seen that the modified form of the invention provides a new and novel means for lachieving the ob- More particularly, vthe corrugated jet pipe arrangement allows a certain degree of longitudinal movement of the jet pipe due to changes in operating temperature or other causes, without imposing extraneous torque conditions upon the carrier 63.

The modified form of jet pipe arrangement shown in Figs. 5 and 6, comprises a metallic pipe 16h, which is formed with two loops or circular bends 162, 164, arranged on eachside of the carrier member arm 55, and with the axis of the loops coinciding with the center of action of the flexure pivot. It will be noted that the loops are arranged in opposite directions, i.e., loop 162 being clockwise, and loop 164 being counter-clockwise, (as seen in Fig. 5). The pipe 160 is secured in a supporting means 165.

The modified form of iet pipe arrangement shown in Figs. 7 and 8, comprises a metallic pipe 168 secured in supporting means 156, a metallic pipe 17) which is formed with one portion in axial alignment with pipe 168, and another portion at a right angle thereto for attachment to the carrier arm 66. A flexible tube or conduit 172, preferably made of a plastic material, is arranged between pipes 158 and 170, in liquid tight manner, whereby a pressure fiuid circuit is provided. A plurality of washers 174 are arranged upon the flexible tube 172, to provide reinforcement against radial expansion. It will be noted that the axis of pipe 16S and the horizontal axis of pipe 17d, coincide with the center 0f action of the flexure pivot.

Vfhile the description has specified the use of an electromotive means for causing pivotal movement of the jet pipe carrier 63 in response to a signal initiated by some exterior condition to be controll^d, other types of carrier movers may be employed with equal effect, such as mechanical means, pneumatic means, or hydraulic means.

The fact that the control device is completely enclosed, allows full liquid submersion of the electrically operated elements and connections, thus making the control device safe for use in explosive atmospheres.

The foregoing description has been given in detail without thought of limitation since the inventive principles involved are capable of assuming other forms without departing from the spirit of the invention or the scope of the following claims.

What is claimed is:

1. A control device having elements including a cylinder and a piston slidably mounted in the cylinder, a jet pipe having a discharge orifice and movable in a predefined path, conduit means for delivering Huid under pressure to said jet pipe for discharge through said orifice, distributor means provided with a pair of receiver ports in the path of movement of said jet pipe orifice, one of said ports being connected via passageway means to one end of said cylinder the other of said ports being con` nected via passageway means to the other end of said cylinder, electromotive means to cause movement of said jet pipe in response to an electrical signal transmitted from outside the control device, resilient means to urge said jet pipe orifice to neutral position between the receiver ports when the forces on the piston are balanced, a housing for enclosing said elements, and a baffle plate arranged in the housing to dampen movement of liquid contained within the housing, said jet pipe being flexible and being formed of a corrugated metal tube. m2. A control device having elements including a cylinder and a piston slidably mounted in the cylinder, a jet pipe having a discharge orifice and movable in a predefined path, conduit means for delivering fluid under pressure to said jet pipe for discharge through said orflce, distributor means provided with a pair of receiver ports in the path of movement of said jet pipe orifice, one or" said ports being connected via passageway means to one end of said cylinder the other of said ports being connected via passage means to the other end of said cylin-v der, electromotive means to cause movement of said jet pipe in response to an electrical signal transmitted from outside the control device, resilient means to urge said jet pipe orifice to neutral position between the receiver ports when the forces on the piston are balanced, a housing for enclosing said elements, and a baffle plate arranged in the housing to dampen movement of liquid contained within the housing, said jet pipe including a pair of loops which are spaced to provide clearance for an arm of the carrier means, said loops being formed with a common axis which coincides with the axis of the pivot about which the carrier means moves.

3. A control device having elements including a cylinder and a piston slidably mounted in the cylinder, a jet pipe having a discharge orifice and movable in a predefined path, conduit means for delivering fluid under pressure to said jet pipe for discharge through said orifice, distributor means provided with a pair of receiver ports in the path of movement of said jet pipe orifice, one of said ports being connected via passageway means to one end of said cylinder the other of said ports being connected via passageway means to the other end of said cylinder, electromotive means to cause movement of said jet pipe in response to an electrical signal transmitted from outside the control device, resilient means to urge said jet pipe orifice to neutral position between the receiver ports when the forces on the piston are balanced, a housing for enclosing said elements, and a baffle plate arranged in the housing to dampen movement of liquid contained within the housing, said jet pipe including a portion which is formed of a flexible material, said portion having reinforcing means about the exterior surface to prevent radial expansion.

4. A control device including a cylinder, a piston slidably mounted in the cylinder, a piston rod attached to the piston and projecting from each end of the cylinder, an t.-shaped carrier member supported by a fiexure pivot whereby one arm of the member is disposed substantially horizontal and the other arm extends downwardly therefrom, a corrugated jet pipe having a nozzle piece at one end which is supported for sliding movement upon the downwardly extending arm, the other end of the jet pipe being afixed to a fixed means, said nozzle piece being formed with an orifice movable in a predened path, a distributor means provided with a pair of receiver ports disposed in the path of movement of said orifice, one of said ports being connected via a passageway means to one end of said cylinder, the other of said ports being connected via passageway means to the other end of said cylinder, an electromotive means to cause pivotal movement of said carrier member about the flexure pivot, said electromotive means including an electrical coil supported at the end of the horizontally disposed arm and a permanent magnet supported in fixed position within and at fixed distance from the coil, a first spring arranged in tension to urge the downwardly extending arm toward the electromotive means, a second spring arranged in tension between the upper end of the piston rod and the horizontally disposed arm, and a housing enclosing all the above defined elements, said housing being arranged to allow projection therefrom of one end of said piston rod.

5. In a control device according to claim 4, wherein the second spring may be tensionally adjustable.

References Cited in the file of this patent UNITED STATES PATENTS

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