CA2015613C - Apparatus for remote adjustment of the stop mechanism for controlling contraction of a hydraulic cylinder - Google Patents

Abstract

A mechanism is disclosed utilizing flexible sheath and a cable is used in remote adjustment of the depth of penetration of the ground by earth working tools such as sweeps of a cultivator. The cable control is used to adjust the distance a piston rod of a power cylinder has to travel before the flow of hydraulic fluid is blocked by a control valve actuated by engagement of an abutment member and a stop plate.

Description

~3 The present invention relates to apparatus for remote adjustment of a control valve for controlling extension or contraction of a piston rod of a power cylinder by alternatively allowing or blocking the flow of hydraulic fluid through said power cylinder. Devices of this type are used in different fields of technology and in particular in farming implements for controlling the length of stroke of a hydraulic or pneumatic cylinder. In most practical applications, the device serves the purpose of controlling the depth of soil penetration by an earth working tool of a farming implement such as the sweep of a cultivator.
Controlling devices of this type are shown in numerous patents. For instance, U.S. Patent 3,972,265 issued August 3, 1976 to Magnuson describes a stroke control mechanism for a hydraulic actuator. It has a piston and cylinder device including a blocking valve which selectively blocks fluid flow from one side of the actuator. The blocking valve is usually a poppet valve. It is actuated by a plate which is mounted to the piston rod of the hydraulic cylinder. As the contraction of the hydraulic cylinder reaches a predetermined position, the plate abuts against a valve rod and closes the blocking valve. The closing results in an interruption of the flow of fluid through the hydraulic cylinder. A similar device is shown in U.S. Patent 3,667,374 issued June 6, 1972 to Patrick, U.S. Patent 2,606,414 issued August 12, 1952 to Dyrr and U.S. Patent 2,606,532 issued August 12, 1952 to Ziskal.
If it is desired to adjust the length at which the path of travel of the piston rod of the hydraulic cylinder is to be terminated, the place at which the tab or plate is mounted to the piston rod is modified. This procedure is cumbersome if the device is used in a heavy farming implement such as a cultivator. The cultivators usually have a master/slave hydraulic system. The location of the master cylinder is usually close to the centre of a relatively complex framework. It is not conveniently accessible. The operator has to climb over the frame and back several times in order ~,~, to adjust the device and to check it. A farming machinery, depth control system, using a selectively adjustable length of chain to trigger the mechanism is shown in the above Ziskal patent 2,606,532.
In U.S. Patent 2,606,414 to Dyrr the control of depth of penetration the ground by a farming implement is effected by connecting a poppet valve associated with a hydraulic cylinder to a chain. The length of the chain is selectively adjustable from the seat of the operator of a tractor. This device has many disadvantages. It is relatively complex. The use of a chain and cable which is slack at certain points of operation may cause misalignment and a subsequent malfunction. The arrangement described also lacks in accuracy of an adjustment.
It is an object of the present invention to improve the art of earth working farming implements and in particular of the control of the hydraulic cylinder used for the purpose described.
Another object of the invention is to facilitate the adjustment of the depth from a convenient location and virtually without having to resort to a trial and error method.
In general terms, the present invention provides apparatus for remote adjustment of the actuation of a control valve for controlling extension or contraction of a piston rod of a power cylinder by alternatively allowing or blocking the flow of hydraulic fluid through said power cylinder, said control valve including a valve housing and a valve member in said housing, the valve member being displaceable from an open position, in which the valve allows the flow through said power cylinder, to a closed position, in which the valve blocks the flow through said power cylinder, said valve member being connected to transmission means for transmitting the movement of the piston rod to the valve member to selectively bring the latter into a closed or open state, said transmission means including a stop tab member and an abutment member, said stop tab member and said 2~ 13 _ abutment member being secured one to said housing and the other to the piston rod such that, on operation of the cylinder, said stop tab member and said abutment member move towards or away from each other along a path which includes a contact point at which the two members abut against each other and move in common to displace said valve member, one of said members including an adjustably displaceable component for adjusting the position of the respective member to thus adjust the length of said path. According to the invention, the adjustably displaceable component includes a first stem slidably received in a first guide, a first end of said first stem extending from one end of said first guide, the guide being fixedly secured to on one of said members, a second end of said first stem being fixedly secured to one end of a flexible cable slidably disposed in an elongated flexible sheath, said flexible sheath having a first end fixedly secured to said first guide, and a second end fixedly secured to a second stem slidable in a second guide which is fixedly secured to a remote support, said second stem being secured to an indicator to allow movement of said indicator along a predetermined indicator locus. The apparatus further comprises lock means for fixedly but releasably securing said second stem relative to said remote support. Thus, the length of displacement of the free end of the first stem is proportional to the length of displacement of the indicator to enable selective adjustment of the length of said path.
The mechanism of flexible sheath combined with a control cable is well known in many fields of technology. Reference may be had, for instance, to arrangements described in U.S.
Patent 1,752,817 issued April 1, 1930 to Spohr, or U.S.
Patent 4,611,502 issued September 16, 1986 to Gregory, U.S.
Patent 4,646,206 issued February 24, 1987 to Bower et al.
The invention will now be described by way of preferred embodiments with reference to the accompanying diagrammatic, simplified, not-to-scale drawings.
FIGURES 1 - 3 show a diagrammatic representation of basic operation of a hydraulic cylinder used in a farming 201~613 _ - 5 -implement with many parts of an associated hydraulic circuit omitted for clarity.
FIGURES 4 and 5 an exemplary representation of two extremes of an adjustment of the device of Figs. 1 - 3.
FIGURES 6 and 7 show diagrammatic perspective views of one embodiment of the present invention in two different positions of adjustment.
FIGURES 8, and 9 are partial top plan views showing elements of the invention used in calibrating a depth adjustment device of a cultivator.
FIGURE 10 (on the sheet of FIGURE 4) is a simplified diagrammatic perspective view of the control of a hydraulic cylinder showing a further feature of the present invention.
FIGURES 11 and 12 present diagrammatic perspective views of two extreme positions of another embodiment of the present invention.
Turning firstly to the arrangement shown in Figures 1 -5, reference numeral 20 shows a housing of a poppet valve member 21. The housing 20 has an inlet/outlet port 22. The port 22 is connected to a first branch C of a hydraulic circuit serving the system shown.
As is well known, the hydraulic system further includes a second branch D, a manual valve y and a fluid supply branch S. The hydraulic circuit itself in well known. It does not have to be shown in greater detail. It will suffice to say that the supply S serves to maintain the system under pressure. The valve V is used in directing the pressurized fluid to one of the two branches C, D, while relieving the other branch D, C. It allow the flow of pressurized fluid through the system in one direction or another to extend or contract the cylinder 23. There are additional known elements of the hydraulic circuit, for instance a return line to a sump.
In the embodiment shown, the housing 20 is integral with a hydraulic cylinder 23. A piston 24 associated with a piston rod 25 is slidable in the cylinder 23 subdividing the cylinder 23 into an upper or first chamber 23a adjacent to _ - 6 the housing 20 and a lower or second chamber 23b. The cylinder 23 is provided with the usual pair of upper mounting brackets 26. A similar pair of mounting brackets 27 is provided at the free end of the piston rod 25. The piston rod 25 carries a stop tab 28. The securement position of stop tab 28 is selectively adjustable along the length of the piston rod 25. The tab 28 faces the lower end of a lifting rod 29. The lifting rod 29, which is an exemplary embodiment of what is generally referred to as "abutment member," is slidable relative to the power cylinder 23 in suitable guide means which is not shown in the drawings for the sake of simplicity.
The arrangement described presents prior art of which many embodiments exist. Reference may be had, for instance, to the Magnuson or Patrick patent.
The axes of the mounting brackets 26 and 27 are designated with reference letters A and B. The particular predetermined distance between the two points A, B determines the spacing of the earth working tools such as cultivator sweeps above the ground in case of transportation (the maximum extension of Figure 1) or the depth of penetration of the ground by the earth working tools at an adjusted minimum extension shown in Figure 3, 4 and 5. The rising of the implement can be achieved either by extension of the piston rod 25 as in the embodiment shown, or by its contraction.
Similarly, the ratio at which the earth working tools (not shown) are lowered or raised is optional. In the present invention, a ratio of 1:2 is preferred (1" of displacement of the piston rod changes the depth by 2").
In Figure 1, oil enters, via branch C, the valve port 22 of the control valve. The valve member or poppet 21 is in open position allowing unrestricted oil flow into the first chamber 23a of the cylinder 23. The fluid forces the piston 24 and rod 25 down. Oil is exiting the lower or second chamber 23b via a port 30 and into the branch D and to an oil sump (not shown). The distance between axes A and B shown in Fig. 1 is at its maximum. The cultivator to which the device is attached is at a fully raised state.
In Figure 2, the oil flow is reversed by manipulating the valve V (not shown in Fig.2). Here the hydraulic fluid enters the second chamber 23b causing the movement of piston 24 upwards. Oil is now exiting the cylinder from the valve port 22 into the branch C (only shown in Fig. 1) and thence to the not shown sump. This operation gradually decreases the distance between points A and B. The distance between the tab 28 and the bottom of the lifting rod 29 is also decreasing. In reference to an associated cultivator, the cultivator frame is being lowered.
In Figure 3, the tab 28 had already made contact at a contact point with the lower end of the lifting rod 29 which then travelled in unison with the tab 28 and has made contact with the lower end of the stem of the valve member or poppet 21. The poppet 21 has thus been raised to block the flow of fluid from the valve port 22, thus blocking the flow of oil through the power cylinder 23. The distance between axes A
and B is now locked at a predetermined setting The distance between points A and B of Fig.3, can be adjusted by adjusting the position of the depth stop tab 28 on the piston rod 25. For example, Figure 4 shows the depth stop tab 28 positioned low on the rod 25 thus blocking the constriction of the cylinder at a set minimum, e.g. 21", resulting in a maximum depth of penetration of the soil.
Figure 5 shows the depth stop tab 28 positioned high on the rod 25 to block the contraction of the cylinder at a greater spacing between A and B. This corresponds to a smaller depth of penetration of the soil. The distance between points A and B is now about 29 inches.
The adjustment of the position of the stop tab 28 along the piston rod 25 is cumbersome and in a location which is difficult to adjust. As a consequence, it takes a long time before the desired depth of the cultivator sweeps or the like is reached. The accuracy of the depth is important for proper operation in modern farming. The convenience of adjustment is important not only for the sake of ease of 2~613 _ - 8 operation but also as a safety feature.
Description will now be made of how the present invention allows the adjustment of the length of the stroke between the extended and contracted position from a remote point and by very simple and thus reliable means. To this end, the invention utilizes a flexible sheath/cable mechanism. The sheath/cable in itself is, of course, known and is not claimed in itself. Since many parts of the transmission of the movement of the piston rod to the valve member are the same as in the known device described, identical reference numerals have been used throughout the drawings to designate the corresponding parts.
Reference may now be had to the representations of Figures 6, 7 and 11. They show a modification of an existing power cylinder. The modified cylinder is that shown previously in Figs. 1 - 5. For the sake of clarity and easy comparison, the same reference numerals have been used for the usual parts such as the hydraulic cylinder 23, the housing 20, axes A, B etc.
The lifting rod 29 is provided with two mounting brackets. A first mounting bracket 31 is fixedly secured, for instance by welding, to the rod 29 near the upper end thereof. The second or lower mounting bracket 32 is likewise fixedly secured, for instance by welding, to the rod 29 at a lower end thereof. The mounting brackets 31 and 32 move in unison with the rod 29 in a vertical direction.
The mounting brackets 31 and 32 hold a tube 33. As best shown in Figure 10, the hold of the tube 33 is resilient. One end (the lower end) of the tube 33 passes through an elongated slot 34 in the lower mounting bracket 32 and is resiliently secured to the upper bracket 31 by way of an end sleeve 35 which is generally integral with the tube 33 but allows lateral displacement of the lower end of the tube 33.
Such displacement is indicated in Figure 10. The sleeve 35 forms a part of a known securement mechanism of a flexible cable disposed in a sheath 36 the arrangement of which will be described later in detail. The cable is not visible in the g drawings. It is secured, at its end near the cylinder casing 23, to a first stem 38 which is slidably received in and protrudes from the lower end of the tube 33. The tube 33 is also referred to as a "first guide" and the stem 38 as a "first stem". The first or lower end portion of the stem 38 is provided forms an abutment member 39. The abutment member 39 faces the top surface of the stop tab 28. The second end of the first stem 38 is not visible. The end 36a (Figs.6 and 7) of the sheath 36 near the power cylinder 23 is also referred to as ~the first end." The opposite end is designated with reference number 36b. The second end of the cable tnot shown) sliding within the sheath 36 is secured to a second stem 40 slidable within a second guide or tube 41 which, in turn, is fixedly secured in a remote support 42.
The remote support 42 includes an upright column 43 firmly secured to a transverse frame member 44 of a cultivator at a position remote from the cylinder 23. Hence the term "remote support".
The second stem 40 can assume, relative to the tube 41, an extended position shown in Figure 6 and a contracted position shown in Figure 7. The free end of the second stem 40 is fixed to a slide 45 which is integral with an invert L-shaped indicator 47. The top, horizontal portion of the indicator 47 forms a rectangular pointer tab 47a. It moves on a straight indicator path or locus along a planar top surface 48 as the slide 45 moves along the slot 46. A lock provided with a threaded knob 49 which is threaded on a bolt passing through the slide 45. It prevents the sliding of the slide 45 along a slot 46 when the handle 49 is in a downward position (Figure 6) and is loose on horizontal position of handle 49.
The planar top surface 48 of the remote support is provided with adjustable linear calibration scale. In the embodiment shown, the scale is a magnetic strip displaying the scale and explanatory remarks. The arrangement of the preferred embodiment of the magnetic strip is apparent from Figures 8 and 9 which correspond to the positions of the slide 45 as shown in Figures 7 and 6, respectively. The magnetic strip or tab 50 has a scale 4 inches long. The indicator has the width of 1/2 inch which, in the embodiment shown, corresponds to the travel the rod 29 has to make from a contact point at which the tab 28 first contacts the abutment member 39, to a full displacement of the poppet 21 within the inner chamber of the housing 20 to a closed position similar to that of Fig. 3. The purpose of this particular thickness will be apparent upon review of the description of the operation of the device which will follow shortly.
In operation, the lock handle 49 is loosened and brought to the extreme left of Figure 10 or Figure 9. This results in a maximum contraction of the first stem 38 so that the abutment member 39 is at its uppermost position. The farming implement, for instance, a cultivator (not shown) is then manually lowered by operating the valve V included in the line system feeding ports 22 and 30. The lowering of the frame of the implement is conducted until such time as the earth working tools, for instance cultivator sweeps, barely rest on the ground. At such point, the piston rod 25 partly projects from the cylinder 23, for example the distance shown in Figure 7. At this point, the slide 47 is moved to the right to assume the position indicated in Figure 7.
This movement results in that the abutment member 39 abuts against the stop tab 28 but does not otherwise influence the instant position of the tube 33 or any other members associated with the mechanism transmission device, inclusive of the lifting rod 29 which is still spaced from the stem of the valve member 21, as shown in Figure 1 or in Figure 2. The space between the uppermost end of the rod 29 and the downwardly facing end of the stem of the poppet 21 plus the distance of poppet 21 to be travelled from the position of Figure 1 or 2 to the position of Figure 3 equals 1/2" which is the width of the tab 47a.
Let it be assumed that the adjustment of Fig. 8 has been locked. The valve V (Fig. 1) may be manipulated to flow the oil from port 22 into the cylinder 23 and out of the cylinder 23 through port 30 into branch D. This results in raising the implement, for instance for transportation or at the turns.
If the flow is now reversed, the oil flows from D into port 30 and from port 22 into C, lowering the frame of an implement. Eventually the tab 28 contacts the lower end of the rod 29 and the two then move another 1/2 inch over the clearance described, until the valve member 21 shuts off the flow of oil through cylinder 23. The earth working tools are thus one inch below the surface. The one inch distance is caused by linkage (not shown) used in the exemplary embodiment of the farming tool. The linkage transmits one inch of the displacement between the cylinder 23 and its cylinder rod 23 to two inches of a drop (or lift) at the frame, in the ratio described.
Accordingly, the set up of Fig. 8 is that of one inch depth of the penetration of the ground because that is the distance the hydraulic cylinder will contract beyond the original calibrating position, when the piston rod 21 and with it the stop tab 28 are lifted.
If it is desired to calibrate a depth different from that shown in Figure 9, for instance to three inches, the indicator is displaced to a position of Figure 10. Here the depth side of the indicator is aligned with number 3. The overall displacement from the position of Figure 9 to Figure 10 is one inch. As already mentioned, this is due to the fact that the linkage of the cultivator with which this exemplary embodiment is used is such that it converts the linear displacement at the calibrating device to twice the length set. In other words, the travel of the piston rod 25 into or out of the cylinder 23 over a given length results in twice the length of actual displacement of the frame of the cultivator up or down.
In summary the operation of the device is generally as shown in Figures 1, 2 and 3 but the effective length of the diagrammatic representation of the rod 29 can be selectively adjusted from a conveniently located position. At the same time, the exactness of the adjustment is also secured.

i~0~$61:~

Turning briefly to the embodiment of Figure 11, it can be seen that the tube 33 is normally held at parallel with the lifting rod 29 but, in case of an unexpected obstacle or the like being encountered, the stop tab 28 has sufficient resiliency to become deflected and to cause the sliding of the abutment member 39 off sideways as is shown in Figure 11.
If for some reason the poppet valve fails to stop the cylinder from contracting, the plate 28 is made flexible enough to yield and thus become inclined to one side, allowing the abutment member 39 to slide over taking with it the free end of the tube 33 to assume the position indicated in Figure 11, at which the tension of the spring 51 has been overcome.
Other embodiments differing from that described above may exist without departing from the scope of the present invention. One such arrangement is shown in Figs. 11 and 12.
As in the first embodiment described, the corresponding members of the modified arrangement of Figures 11 and 12 utilizes the same reference numbers.
It should be firstly mentioned, that the modification is only at the first guide 33, while the arrangement of the remote support is identical to Figs. 6 and 7.
In Figs. 11 and 12, the stop tab 28 is fixedly secured to the free end of the first stem 38. The tube 33 is fixedly secured to a rod 52 which is fixedly secured with respect to, and moves in common with, the piston rod 25. Accordingly, the manipulation of the calibrating end of the mechanism as shown in Figures 9 and 10 results in displacement of the tab 28 in the desired direction rather than in the movement of the free end of the first stem 38 towards or away from the tab 28.
The remaining operation, for instance the sideways displacement of the first stem 38 in case of emergency (Figure 10) is enabled by the relative arrangement of a slot 34 in tab 28 and another slot 34a in a guide 53 which is fixedly secured to the rod 52. The spring 51, of course, normally holds the tube 33 parallel with the rod 52 as shown in both Figures 11 and 12.

20~561;~

It will thus be appreciated that the present invention provides an extremely simple, yet accurate device for adjustment of the depth of operation of cultivators or other earth working farming implements.
As already mentioned, there are many variants which can be made within the frame work of the present invention. The second embodiment described is but one of such variants.
Accordingly, we wish to protect by letters patent which may issue on the present application all such embodiments as properly fall within the scope of our contribution to the art.

Claims (9)

1. Apparatus for remote adjustment of the operation of a control valve for controlling extension or contraction of a piston rod of a power cylinder by alternatively allowing or blocking the flow of hydraulic fluid through said power cylinder, said control valve including a valve housing and a valve member in said housing, the valve member being displaceable from an open position, in which the valve allows the flow through said power cylinder, to a closed position, in which the valve blocks the flow through said power cylinder, said valve member being connected to transmission means for transmitting the movement of the piston rod to the valve member to selectively bring the latter into a closed or open state, said transmission means including a stop tab member and an abutment member, said stop tab member and said abutment member being secured one to said housing and the other to the piston rod such that, on operation of the cylinder, said stop tab member and said abutment member move towards or away from each other along a path which includes a contact point at which the two members abut against each other and move in common to displace said valve member, one of said members including an adjustably displaceable component for adjusting the position of the respective member to thus adjust the length of said path, characterized in that said adjustably displaceable component includes a first stem slidably received in a first guide, a first end of said first stem extending from one end of said first guide, the guide being fixedly secured to on one of said members, a second end of said first stem being fixedly secured to one end of a flexible cable slidably disposed in an elongated flexible sheath, said flexible sheath having a first end fixedly secured to said first guide, and a second end fixedly secured to a second stem slidable in a second guide which is fixedly secured to a remote support, said second stem being secured to an indicator to allow movement of said indicator along a predetermined indicator locus;

the apparatus further comprising lock means for fixedly but releasably securing said second stem relative to said remote support;

whereby the length of displacement of the free end of the first stem is proportional to the length of displacement of the indicator to enable selective adjustment of the length of said path.

2. Apparatus of claim 1, wherein the first guide is fixedly secured relative to said abutment member.

3. Apparatus of claim 1, wherein the first guide is fixedly secured relative to said stop tab.

4. Apparatus of claim 1, wherein the indicator is pointer tab fixedly secured to a slide slidable in said remote support along a linear calibrated scale parallel with the axis of said second stem, whereby the length of linear displacement of the slide is equal to the length of displacement of the first end of said first stem.

5. Apparatus of claim 4, wherein the pointer tab has a thickness equal to the distance between said contact point and a point at which the valve member assumes an opposite terminal position.

6. Apparatus of claim 4 or 5, wherein said scale is provided on an elongate magnetic tab and wherein the remote support includes a planar ferromagnetic surface portion whose width generally corresponds to that of the magnetic tab and whose length is in excess of that of the magnetic tab, whereby the magnetic tab can be selectively displaced on calibration of the device.

7. Apparatus of claim 1 wherein the first guide is secured to a lifting rod for controlling a poppet valve of a master cylinder of a master/slave hydraulic cylinder system for controlling the depth of earth penetration by a an earth working farming implement, and the stop tab is fixedly secured to the piston rod of said master cylinder.

8. Apparatus of claim 3, wherein the abutment member is a lifting rod for controlling a poppet valve of a master cylinder of a master/slave hydraulic cylinder system for controlling the depth of earth penetration by a an earth working farming implement, and the stop tab is fixedly secured to the piston rod of said master cylinder.

9. Apparatus of claim 5 or claim 6, wherein the first guide includes resilient mounting means for securement of the first guide to the respective member such as to allow resilient lateral displacement of the first end of the first stem, the stop tab member being to yield, when subjected to an excessive pressure on accidental excessive contraction of the cylinder, from a position in which the tab is at right angles to the first guide to an oblique position wherein the tab causes said lateral displacement of the first end of the associated first stem.