US2879644A

US2879644A - Apparatus for moving and positioning a movable means

Info

Publication number: US2879644A
Application number: US557975A
Authority: US
Inventors: Joseph H Caslow; Donald J Detrich
Original assignee: American Brake Shoe Co
Current assignee: American Brake Shoe Co
Priority date: 1956-01-09
Filing date: 1956-01-09
Publication date: 1959-03-31
Anticipated expiration: 1976-03-31

Description

March 31', 1959 c s ow r 2,879,644

APPARATUS FOR MOVING AND POSITIONING A MOVABLE MEANS Filed Jan. 9, 1956 4 SheetsSheet 1 Fig.

INVENTORS. JOSEPH H. CASLOW BY DONALD J. DETR/CH AGENT Mrch 31, 1959 J. H. CASLOW ETAL APPARATUS FOR MOVING AND POSITIONING A MOVABLE MEANS Filed Jan. 9, 1956 4 Sheets-Sheet 2 INVENTORS. JOSEPH H. CASLOW B DONALD J. DE TRICH AGENT March 31, 1959 J. H. cAsLow ETAL 4 APPARATUS F OR MOVING AND POSITIONING A MOVABLE MEANS Filed Jan. 9, 1956 4 Sheets-Sheet 3 INVENTORS. JOSEPH H. CASLOW DONALD J. DETRICH GEN T March 31, 1959 J. H. CASLQW EIAL APPARATUS FOR MOVING AND POSITIONING A MOVABLE MEANS Filed Jan. 9, 1956 4 Sheets-Sheet 4 INVENTORS. JOSEPH H. CASLOW B DONALD J. DETR/CH AGENT United States atent APPARATUS FOR MOVING AND POSITIONING A MOVABLE MEANS Joseph H. Caslow and Donald J. Detrich, Columbus, Ohio, assignors, by mesne assignments, to American Brake Shoe Company, New York, N. Y., a corporation of Delaware Application January 9, 1956, Serial No. 557,975

2 Claims. (Cl. 60-54.5)

This invention relates to hydraulic apparatus for initiating and then continuing the movement of an element to a desired position and in which the direction of motion of the element may be caused to occur either in one or reverse directions.

An object of this invention is to provide improved apparatus for initiating and continuing the movement of a means to be moved by first applying a high hydraulic pressure against the means to initiate its movement and thereafter reducing the pressure to continue the movement of the movable means.

In carrying out the foregoing object, it is another object of the invention to provide an improved apparatus including a movable means and a chamber adapted to contain liquid the pressure of which acts upon said movable means to move it, and to provide means preferably, but not necessarily, in the form of a pair of pistons, one of small diameter and the other of larger diameter, and the smaller of which may be moved by a small force to increase the pressure of said liquid materially thereby to initiate movement of the movable means and the larger of which may then be moved to act on said liquid to cause continuing movement of said movable means.

Another object of the invention is to provide improved apparatus of the type set forth in the foregoing objects in which the means for creating the pressure referred to is operated by solenoid means.

Another object of the invention is to provide improved hydraulic apparatus for moving a member to different positions in which movement of the member to different positions is accompanied by the displacement of liquid and the position or positions to which said member is moved is determined by measuring and limiting the quantity of liquid which can be displaced.

Another object of the invention is to provide improved hydraulic apparatus for moving a member to different positions in which movement of the member to different positions is accompanied by the displacement of liquid which must flow through a restrictor means thereby to limit the speed of movement of the movable member.

Another object of the invention is to provide improved hydraulic apparatus for moving a member to different positions in which movement of the member to different positions is accompanied by the displacement of liquid which flows to an accumulator and a restrictor means in parallel thereby to control the movement of the movable member.

Still another object of the invention is to provide improved apparatus of the type set forth in the foregoing objects which is electrically operated, as, for example, through push button switches.

Further objects'and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred form of embodiment of the invention is clearly shown.

2,879,644 Patented Mar. 31, 1959 In the accompanying drawings:

Fig. l is a diagrammatic showing of the improved hydraulic apparatus employed for the purpose of moving and positioning the spool or core of a four-way hydraulic valve which valve, in turn, controls the operation of a reciprocatory hydraulic motor, the view showing the parts of the hydraulic apparatus in the positions which they occupy when the spool or core of the four-way valve is in its central or neutral position and the electrical system shown in Fig. 4 is de-energized;

Fig. 2 is a view of the hydraulic apparatus seen in Fig. l, but showing the parts of the apparatus in the positions which they occupy when the core or spool of the four-way valve is shifted to the right-hand position;

Fig. 3 is a view of the hydraulic apparatus seen in Fig. 1, but showing the parts of the apparatus in the positions which they occupy immediately after the core or spool of the four-way valve has been returned from the right-hand position to its central or neutral position, and

Fig. 4 is a diagrammatic showing of the electrical circuit and mechanism of the apparatus.

Figs. 1 through 3 of the drawings show the improved hydraulic apparatus of this invention applied to a fourway hydraulic valve 10 which is shown, for the purpose of illustration only, as controlling the operation of a high pressure reversible hydraulic motor 11 of the piston and cylinder type.

Valve 10 includes a body, casing or housing made up of a main portion 12 and a pair of

end caps

13 and 14. The main body portion 12 includes a bore 15 within which there is a valve core or spool 16 provided with a central land 17 and lands 18 at its opposite ends. The body 12 is provided with the usual annular channels, grooves or

recesses

19, 20, 21, 22 and 23 which surround the central bore 15 and these grooves may be interconnected through the bore 15 in various combinations by shifting the core or spool 16 axially to different positions in the bore.

As shown in the drawings, the central annular groove 19 in body portion 12 constitutes the high pressure or inlet port of the valve and it receives hydraulic fluid from any suitable source, such for example, as a pump, not shown. The

annular grooves

20 and 21 which flank the central groove 19 are connected, respectively, through suitable conduits to opposite ends of the cylinder of motor 11 and the

end grooves

22 and 23 are connected with the exhaust or tank port 24 in the valve body 12.

When the valve core or spool 16 is in its central or neutral position, as shown in Fig. 1 of the drawings, all of the annular grooves 19 through 23 are isolated from each other and the motor 11 is blocked or locked against movement. When the valve core or spool 16 is shifted to the right, as shown in Fig. ,2, the central groove 19 is connected through the bore 15 with the groove 20 to supply hydraulic fluid under pressure to the left-hand end of the cylinder of motor 11 to cause the piston and ram of said motor to be extended. Hydraulic fluid may be discharged from the right-hand end of the cylinder of motor 11 by flowing through groove 21, bore 15 and groove 23 to exhaust. When the core or spool 16 is moved to its left-hand position, not shown, hydraulic fluid under pressure is supplied to the right-hand end of the cylinder of motor 11 by flowing from the groove 19 through bore 15 to groove 21 and fluid flowing from the left-hand end of motor 11 passes from groove 20 to groove 22 and to exhaust.

The apparatus herein described and claimed may be employed for initiating and continuing the movement of substantially any member or thing to be moved and it is shown and described herein inconnection with a hydrauice lie valve because such s valve presents an excellent mechanism with which. to illustrate the invention.

It is well known in the hydraulic art that the cores or spools of hydraulic valves employed to control hydraulic fluid under high pressures often stick or freeze in the valve body and that. very great forces may be required to initiate their movement. It is also well known that once the movement of the core or spool is initiated that the force required to continue its movement is considerably lessened. By this invention, there is provided improved apparatus which will first apply a very high hydraulic pressure to the core or spool of the valve to initiate its movement and which will thence reduce the hydraulic pressure to continue the movement of the core or spool, and. by this invention there is also provided an apparatus which may be operated by electromagnetic solenoids without the danger' of burn outs thereof caused by the failure of the-valve core or spool to move.

Turning attention again to the valve 10, this valve, as previously pointed out, includes two

end caps

13 and 14 secured to opposite ends of the body portion 12 and these end caps cooperate in providing chambers or

compartments

25 and 26, one at each end of the core or spool 16. These chambers or

compartments

25 and 26 are each adapted to contain liquid to which one of the piston means 27 formed by one of the end lands 1? of core or spool 16 is exposed.

The valve 18 is of a self-centering type, that is, its core or spool 16 is caused to move to its central or neutral position, as shown in Fig. 1, whenever it is not being held in either its left or right-hand position. The centering mechanism for the core or spool 16 includes a washer 28 in each of the

chambers

25 and 26 which is carried loosely on a stub extension of the valve core 16. A spring 29 in each

chamber

25 and 26 urges the washer 28 therein against a shoulder provided by the end of the body portion 12, and when both washers 28 are held against such shoulders the core or spool 16 is, of course, held resiliently in its central or neutral position.

As shown in the drawings, chamber 26 is connected through conduits or

passages

30 and 31 to the interior of a pressure generator 32 which includes a housing or casing 33 having a stepped diameter chamber, compartment or cylinder 34 which receives a piston assembly 35 that reciprocates in its large diameter portion.

Piston assembly 35 is comprised of a large diameter piston 36 having a central. bore through. which a small diameter piston 37 extends. The small diameter piston 37 is formed as a reduced diameter extension of an armature 38 of an electro-magnetic solenoid 39 (see Fig. 4) and it is carried for reciprocatory movement in an end cap 40 on the housing 33. The length of piston 37 is greater than the thickness of piston 36 whereby when the armature 38 is first moved to the left the small piston 37 will slide through the large piston 36 and displace a small quantity of liquid under high pressure from the chamber or cylinder 34 into the conduit 31 before a shoulder 41 on the armature 38 engages the large piston 36 and causes it to move inwardly in the chamber or cylinder 34 to displace liquid therefrom at a lower pressure. The piston assembly 35 is urged to the position shown in Fig. 1 of the drawings by a spring 42 which engages a snap ring on the innermost end of the small diameter piston 37.

The chamber or compartment25 in valve cap 13 is connected through conduits or.

passages

43 and 44 to a pressure generator 45.v which is; identical. in. construction. to the pressure generator. 32 and which, therefore, will not be described further.

The conduits or

passages

30 and 43 leading from the

liquid chambers

25 and 26 to the

pressure generators

32 and 45 are also connected to a spool type valve'46 which includes a body, casing or housing 47 having a bore 48 4 which receives a core or spool '49 provided with spaced lands 5t), 51 and 52. The body 47 of valve 46 provides six annular channels or

grooves

53, 54, 55, 56, 57 and 58 which surround the bore 48 and certain of which may be interconnected through the bore when the core or spool 49 is shifted axially to different positions therein.

The conduits or

passages

30 and 43 are connected, respectively, to the

grooves

55 and 56.

Grooves

54 and 57 are connected, respectively, to measuring devices 59 and 6b which function in the nature of hydraulic accumu lators, and the

grooves

53 and 58 are connected, respectively, through

conduits

61 and 62 which include

variable orifices

63 and 64 with a liquid reservoir or tank 65. The conduits or

passages

61 and 62 are also connected to receive liquid from the reservoir or tank 65 through conduits or passages 66 including two

check valves

67 and 68 which function to admit liquid freely from the tank 65 to the hydraulic system, and for preventing the flow of liquid to the tank except through one of the

orifices

63 or 64.

The

liquid measuring devices

59 and 69 are identical in construction and each of them includes a body casing or housing 69 which provides a chamber 70 in the form of a stepped cylinder which receives a piston 71 which is urged to exhaust liquid from the chamber 70 by a spring 72. The maximum quantity of liquid which can be forced into the chamber 70 of each measuring

device

59 and 60 is determined by the location of the shoulder 73 which limits movement of the piston 71. In the embodiment of the invention shown, this maximum quantity of liquid is exactly equal to one-half of the maximum volumetric capacity of either of the

chambers

25 or 26.

The valve 46 is also of a self-centering type, that is, its core or spool 49 is resiliently urged to its center or neutral position by a pair of springs 74 which surround

extensions

75 and 76 of the core or spool 49 which extend through end caps 77 on the valve body 47 and are connected, respectively, to the

armatures

78 and 79 of electric motors which are shown here as including electromagnetic solenoids 80 and 81 (see Fig. 4).

Axial movement of the core or spool 49 of valve 47 may be limited by a pair of stops 82 which are resiliently urged into the bore 48 by compression springs 83 and which may be withdrawn therefrom by the armatures 84 of electromagnetic solenoids 85 (see Fig. 4).

An electric circuit for operating the hydraulic mechanism above described is shown diagrammatically in Fig. 4 of the drawings and it is such that the hydraulic apparatus can be operated from a remote position by means of three push button switches which are labeled R for right, C for center, and L for left to indicate the position to which the spool or core 16 of valve 10 will be moved when each switch is operated. The electric circuit shown in Fig. 4 will best be understood by describing its operation.

When the electric circuit is de-energized, the spool or core 16 of valve 10 will be in its central or neutral position and, when it is desired to cause the spool or core 16 to be moved from this position to its right-hand position, switch R is closed thereby connecting current supply line 86 with a line 87 connected with line 88 to one side of the coil 89 of a solenoid operated relay type contactor 90. The other side of coil 89 is connected to the other current supply line 91 through

lines

92 and 93. Immediately upon the closing of switch R, the contactor apparatus will be operated. Contactor apparatus 90 includes five

switches

94, 95, 96, 97 and 98 and, upon the energizing of its coil 89, it first opens switch 95 and closes switch 98 following which it closes switches 94, 96 and Y97. When switch 98 is closed, it completes a circuit to solenoid coil 89 of valve 46 through

lines

91, 93, coil 81, line 99, switch 98,

lines

100, 87 and switch R to line 86 thereby shifting the valve core or spool 49 of valve 46 to, the right and against one of the stop pins 82.

It may be mentioned here that the switch 98 is closed before the

switches

94, 96 and 97 in order that the core 49 of valve 46 will be positioned as described above before the coil 39' of pressure producer 45 is energized. When switch 97 closes, it completesa holding circuit for coil 89 which includes

lines

86, 119, switch 125, line 126, switch 108 of contactor 103, line 120, switch 97, line 88, coil 89,

lines

92, 93 and 91. When switch 94 closes, it completes a circuit to energize the coil 39' which includes

lines

91, 93, 92, coil 39, line 101, switch 94,

lines

100, 87 and switch R to line 86. When coil 39' is energized, the pressure producer 45 is operated to cause the core 16 of valve to be shifted to its right-hand position.

When it is desired to cause the spool or core 16 of valve 10 to be moved from its right-hand to its left-hand position, push button switch L is operated to complete a circuit to coil 102 of a solenoid operated relay contactor 103 which is identical to the contactor apparatus 90. This circuit includes

lines

86, 104, switch L,

lines

105, 106, coil 102, line 107 and line 91. Immediately upon the closing of switch L, the coil 102 of contactor apparatus 103 is energized to first open switch 108 and close switch 109 to energize coil 80 of valve 46 and then to close

switches

110, 111, and 112. The closing of switch 111 completes a holding circuit for the coil 102 of contactor apparatus 103 including

lines

86, 113, switch 95, line 114, through switch 127, line 128, switch 111,

lines

115, 105, 106, coil 102, line 107 and line 91.

When switch 108 opens, the contactor apparatus 90 is de-energized closing switch 95.

When the coil 102 of contactor 103 is energized, the switch 109 is the first to be closed to energize coil 80 of the valve 46 to cause its core or spool 49 to be moved to the left against the left-hand stop 82 and, after this action occurs, switches 112, 111, and 110 are closed. Upon the closing of switch 112, a circuit for coil 39 of the pressure generator 32 is completed. This last-named circuit includes lines 91, 116, coil 39, line 117, switch 112,

lines

118, 105, 115, switch 111, line 128, switch 127, line 114, switch 95, and line 113 to line 86.

When switch 111 of contactor 103 closes, it completes a holding circuit for coil 102 which includes

lines

86, 113, switch 95 of contactor 90, line 114, switch 127, line 128, switch 111,

lines

115, 105, 106, coil 102 and line 107 to line 91.

When it is desired to cause the core or spool 16 of valve 10 to be moved from its left-hand to its center or neutral position, switch C is closed. The first movement of switch C opens

switches

125 and 127 insuring the deenergization of

coils

89 and 102 before the switch 129 closes. The closing of switch 129 first energizes coils 85 of valve 46, and coil 89 of contactor 90 and then contactor 90 first energizes coil 81 of valve 46 and then coil 39' of the pressure generator 45. The circuit for energizing coils 85 may be traced as follows:

lines

86, 104, 124, switch 129, line 121, coils 85, line 122,

lines

93 and 91. The circuit for energizing relay coil 89 of contactor 90 comprises

lines

86, 104, 124, switch 129, line 123, switch 110,

lines

87, 88, coil 89,

lines

92, 93 and 91.

Switch 129 is held closed manually until the spool or core 16 of valve 10 is moved to its center or neutral position. When switch C is released, switch 129 is opened to de-encrgize the system and then switches 125 and 127 are closed to condition the circuit for the reestablishment of the holding circuit of either

contactor coil

89 or 102 depending upon which of the switches R or L is next to be operated.

From the foregoing description of the electric circuit, it will be seen that, when any of the switches R, C or L is operated, the spool or core 16 of valve 10 will respond regardless of the position which it occupied prior to the closing of said switch R, C or L.

In the operation of the hydraulic system, when the spool or core 16 of valve 10 is in its center or neutral position, the other operating elements of the system are in the positions shown in Fig. 1. In this position of the elements, the spool or core 49 of valve 46 is also in its center or neutral position and the

chambers

25 and 26 as well as the

pressure generators

32 and 45 and the measuring

devices

59 and 60 are connected to tank 65.

When it is desired to shift the core or spool 16 of valve 10 to the right, push button switch R is closed to energize the circuits above described which cause the coil 81 to be energized to move or shift the core 49 of valve 46 to the right and against the right-hand stop 82 (see Fig. 2). Upon shifting to this right-hand position, the center land 51 of core 49 blocks the channel 56 whereby all fluid later displaced from the pressure generator 45 must pass into the chamber 25.

When the core 49 is positioned against the right-hand stop 82, the conduit or passage 30, the pressure generator 32 and the measuring device 59 remain connected with tank 65 through conduit or passage 61 and the variable orifice 63 to permit liquid to be displaced from cham ber 26.

Because of the time delay action of contactor 90, coil 39' of pressure generator 45 is not energized until core 49 of valve 46 is shifted to the right-hand position above described in'which it blocks channel 56. Upon the energization of coil 39, the armature 38' for pressure generator 45 is moved to the right to force the small diameter piston 37 into the cylinder 34, thereby creating exceedingly high hydraulic pressure in the cylinder 34', the conduit or pasasge 43 and the chamber 25. Since the piston means 27 at the left-hand end of core 16 is exposed to this pressure, the core 16 will be forced, even though it may be stuck or frozen in the body 12, to move to the right. After this right-hand movement of the core 16 is initiated by the movement of the small piston 37', the shoulder 41 on armature 38 will engage the large diameter piston 36 to cause it to continue the displacement of liquid from the pressure generator 45 into the chamber 25 thereby continuing the movement of the core 16 until its right-hand end abuts a stop in the chamber 26. It will be seen that once movement of the core 16 has been initiated that the force necessary to continue its movement is reduced and that therefore the hydraulic pressure in chamber 25 and cylinder 34' will be reduced to such a degree that the solenoid 38', 39" acting through the combined pistons 36' and 37' can continue to move to displace an increased volume of liquid thereby insuring that the armature 38' will move to its limit and prevent damage by burning out of the coil 39'.

It is an inherent characteristic of solenoids that their armatures operate with a very quick or snap action and in this device the rate of movement of the armatures 38, 38' and core 16 can be adjustably controlled by the measuring

devices

59 and 60 and the adjustable or

variable orifices

63 and 64. For example, when the core 16 is being moved to the right as just explained, liquid must be displaced from the chamber 26 and this liquid may be caused to flow partly into the measuring device 59 and partly through the orifice 63 to tank 65 while the core 16 is moving, and after the core reaches its limit of movement, liquid which has been forced into the measuring device will be bled to tank through orifice 63. It will, therefore, be seen that each of the measuring devices has a dash-pot and shock absorber function and that the rate or speed of travel of the core 16 and

armatures

38, 38'. may be controlled or predetermined by adjusting the

variable orifices

63 and 64. The conduit or passage 66 and

check valves

67 and 68 are provided to permit the system to receive liquid from tank 65 whereby the system will remain filled with liquid at all times.

It will be apparent that when the core 16 of valve 10 is to be moved to its left-hand position, that upon the closing of switch L core49 of valve 46 will be moved to its left-hand position against the left stop 82 and that pressure generator 32 will then be operated, all in a manner similar to that described above when the core 16 is moved to the right, to cause movement of the core 16 to its left-hand position.

When the core 16 of-valve is to be moved to its center or neutral position, for example from its righthand position, switch C is closed to energize coils 85 thereby withdrawing stops 82 from the bore 48 of valve 46 to permit the core 49 to move further to the left as shown in Fig. 3 of the drawings. In this position of core 49, its land 52 blocks channel 58 and causes liquid displaced from the chamber 25 to flow into the measuring device 60 and since the volumetric capacity of this device 60 is exactly one-half the maximum volumetric capacity of chamber 25 the spool can move only to its center position when the pressure generator 32 is operated by energization of its coil 39. Obviously, when core 16 is to be moved from its left-hand position to its center position, the core 49 will be moved to its maximum right-hand position and measuring device 59 will function to limit the quantity of liquid which can be displaced from the chamber 26.

After core 16 moves to its center position, the manually operated switch C is released to tie-energize the electric circuit and springs 74 will center the core 49 in bore 48 of valve 46 restoring the parts to the position shown in Fig. 1 of the drawings.

It will be seen that the valve 46 will be subjected to high hydraulic pressures only when the small diameter pistons 37 and 37' are operated to initiate movement of the core 16 and that otherwise the maximum hydraulic pressure on the valve 46 will be determined by the relatively light springs 29. For this reason, the core 49 will not tend to stick or freeze in the bore 48.

It will be obvious to those with knowledge of the art that the foregoing description and the drawings teach the construction and operation of apparatus in which a vmember, such for example as the core or spool 16 of valve 10, may be moved to threc'difierent positions. it will also be obvious that the apparatus may be modified expediently by the omission of elements and their functions to provide an apparatus wherein the member may be moved in reverse directions between two positions. Such modification could include the omission of the selfcentering features of

valves

10 and 46, the push button C and its functions as well as the coils 85.

While the form of embodiment of the present invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

We claim:

1. Hydraulic apparatus for initiating and continuing the movement of a member to difierent predetermined positions including a member to be moved, a pair of piston means, means forming a chamber for each of said piston means adapted to contain a liquid exposed to said piston means, means for acting on the liquid in one of said chambers for first applying a high hydraulic pressure to said piston means for initiating movement of said member and then applying a lower hydraulic pressure to said piston means to continue the movement of said member, movement of said member causing the other of said piston means to displace liquid from the other of said chambers, and means for predetermining the quantity of liquid which can be displaced from said other chamber thereby determining the positon to which said member shall be moved.

2. Hydraulic apparatus for initiating and continuing the movement of a member alternately in opposite directions and to different predetermined positions in each direction including a member to be moved, a pair of piston means for moving said member as aforesaid, means forming a chamber for each of said piston means adapted to contain a liquid exposed to said piston means, means for acting on said liquid in each of said chambers for first applying a high hydraulic pressure to said piston means for initiating movement of said member and then applying a lower hydraulic pressure to said piston means to continue the movement of said member, movement of said member causing the other of said piston means to displace liquid from the other of said chambers, and means for predetermining the quantity of liquid which can be displaced from each of said chambers thereby determining the position to which said member shall be moved.

References Cited in the tile of this patent UNITED STATES PATENTS 799,064 Kowsky Sept. 12, 1905 1,673,528 Pigeolet June 12, 1928 1,737,649 Edsall Dec. 3, 1929 1,980,617 Engel Nov. 13, 1934 2,161,279 Bowen June 6, 1939 2,361,326 Silver Oct. 24, 1944 2,437,115 Muller et al Mar. 2, 1948 2,501,661 Christensen Mar. 28, 1950 2,526,646 Ericson Oct. 24, 1950 2,613,703 Calvert Oct. 14, 1952