US3691908A

US3691908A - Combined hydraulic and mechanical detent disengaging means

Info

Publication number: US3691908A
Authority: US
Inventors: Larry G Hackmann; James L Schmitt
Original assignee: Caterpillar Tractor Co
Current assignee: Caterpillar Inc
Priority date: 1971-06-14
Filing date: 1971-06-14
Publication date: 1972-09-19
Anticipated expiration: 1989-09-19

Abstract

Hydraulic kick-out circuitry and mechanism for automatically releasing work implement control valves from detented positions to neutral positions when the work implement actuating hydraulic cylinders controlled by the valves reach the ends of their strokes. The arrangement is such that in a multiple control valve system the valves are released in a sequential order with a low kick-out force which can be overriden by the operator when necessary.

Description

United States Patent Hackmann et a1.

1541 COMBINED HYDRAULIC AND MECHANICAL DETENT- DISENGAGING MEANS Inventors: Larry -G. Hackmann; James L.

Schmitt, both of Washington, Ill.

Assignee: Caterpillar Tractor Co., Peoria, 111.

Filed: June 14, 1971 Appl. No.: 152,713

US. Cl. ..91/4l2, 91/414, l37/624.27 Int. Cl. ..Fl5b 11/16, Fl5b 13/01 Field of Search ..9l/412, 414; l37/624.27

[56] References Cited UNITED STATES PATENTS 1,968,422 7/1934 Proctor et a1 ..9l/4l4 X nsr 3,691,908

1 5 Sept. 19, 1972 2,184,793 12/1939 Clench ..9l/414 X 2,844,942 7/1958 Reynolds ..9l/4l2 X 2,918,902 12/1959 Robinson et al. ..91/41 2 X 4 Primary Examiner-Edgar W. Geoghegan Attorney-Charles M. Fryer et a1.

57] ABSTRACT Hydraulic kick-out circuitry and mechanism for automaticallyv releasing workimplement control valves from detented positions to neutral positions when the work implement actuating hydraulic cylinders controlled by the valves reach the ends of their strokes.

The arrangement is such that in a multiple control valve system the valves are released in a sequential order with a low kick-out force which can be overriden by the operator when necessary.

9 Claims, 3 Drawing Figures PATENTEDSEP 19 I972 sum 2 or 3 INVENTORS LARRY G. HACKMANN JAMES L SCHMITT PATENTED SEP 19 1972' SHEU 3 OF 3 INVENTORS LARRY G. HACKMANN JAMES L. SCHMITT .7 i l ATTORNEYS BACKGROUND OF THE INVENTION In various earth-movin g special application machines and the like equipped with hydraulically actuated work implements it is desirable that the production cost be kept at an absolute minimum in order that such machines may be made economically available to small or individual consumers. In order to facilitate convenient control of the functions of the various work implements, lever operated control valves are generally associated with the hydraulic actuating cylinders thereof to control the flow of pressurized hydraulic fluid thereto in accordance with lever manipulation by the operator. Each valve is typically of the multiple position spool variety wherein the spool is translatable by lever action between raise, neutral, and lower positions, and oftentimes a float position.

The spools are generally detented in at least the raise position in order that the operator does not have to hold the levers in position until such time as the associated actuating cylinders complete their raise strokes. However, for purposes of operational efficiency it is desirable that the spools be automatically released to their neutral positions when the raise strokes are completed without necessitating lever manipulation by the operator.

Heretofore, automatic hydraulic kick-out circuitry and mechanism for this purpose have been relatively complicated and costly to manufacture, thereby seriously detracting from the desired overall minimum production cost of the machine.

SUMMARY OF THE INVENTION The general object of the present invention is to provide a relatively simple and low cost kick-out system for automatically disengaging a detented spool of a hydraulic control valve and returning same to a neutral position responsive to the completion of a predetermined stroke of a work implement hydraulic actuating cylinder controlled by the valve.

As an advantageous feature of the system, when same is employed in a multiple control valve arrangement, actuated valves are released to neutral positions in a sequential order with a low kick-out force which can be overridden by the operator when desired.

In the accomplishment of the foregoing and other objects and advantages, detent disengaging means in accordance with the present invention generally include in combination with a source of pressurized fluid and multiple control valve means coupling the source to work implement actuating hydraulic cylinders, pressure sensitive kick-out mechanism and circuitry coupled to the source to actuate a hydraulic kick-out cylinder when system pressure exceeds a predetermined value corresponding to that at the ends of the strokes of the implement actuating cylinders, and means coupled to the kick-out cylinder for releasing spools of the control valve means from a detented position to a neutral position in a sequential order with a low kick-out force responsive to actuation of the kickout cylinder.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic hydraulic circuit diagram of a detent disengaging system in accordance with the present invention.

FIG. 2 is a front elevational view of mechanical components of the system. I

FIG. 3 is a side elevational view of the mechanical components.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION Referring now to FIG. 1 in detail, there is shown a source of pressurized hydraulic fluid such as a pump 1 1 communicated with a reservoir 12. The pump delivers fluid to a line 13 and a line 14 which in turn communicates with a group of implement

control valves

16, 17 and 18 connected together in a series relationship.

A return line 19 from the valves is communicably connected to a filter assembly 21, which is communicably connected to the reservoir by means of a line 22. The filter assembly is of conventional design and includes a filter element 23 and bypass valve 24.

A relief valve 26 is coupled between supply line 13 and return line 19 to protect the valves and associated hydraulic components subsequently described from over pressures.

The

valves

16, 17 and 18 are respectively coupled in controlling relation to work implement actuating

hydraulic cylinders

27, 28 and 29. The

valves

16, 17 and 18 are of the multiple position spool actuated type, and consequently respectively include

spools

31, 32 and 33 which are selectively translatable between a plurality of flow control positions.

More particularly, in the illustrated case valves 16 and 17 have raise (R), neutral (H), lower (L), and float (F) spool positions, while valve 18 has raise (R), neutral (H) and lower (L) spool positions. In the neutral positions of the valves, the supply line 14 is communicated with return line 19 and communication to the opposite ends of the implement actuating

cylinders

27, 28 and 29 is blocked. I I

When the spool of a valve is shifted to its raise position, flow is established from supply line l4 to the left end of the corresponding actuating cylinder (as viewed in FIG. 1) and flow is established from the right end of the cylinder to return line 19, thereby causing the piston rod of the cylinder to undergo a raise or retraction stroke.

Conversely, in the lower position of each valve, flow is established from supply line 14 to the right end of the corresponding cylinder while flow is established from the left end of the cylinder to return line 19, thereby causing the piston rod of the cylinder to undergo a lower or extension stroke. In the float position of valve 16 or 17, flow is established between the supply and return lines 14 and 19 and between both ends of the corresponding cylinders and the return line.

Translation of the

spools

31, 32 and 33 of

valves

16, 17 and 18 between the various positions thereof is facilitated by means of

levers

34, 36 and 37 mechanically coupled thereto. In addition the spools are detented in their raise positions and

spools

31 and 32 are also detented in their float positions, as schematically depicted by notches 38. Such detenting of the valve positions is accomplished in a conventional manner as by means of spring-loaded ball and groove combinations (not shown). Thus, by manipulating the levers, the valve spools are shifted from position toposition,

- and are resiliently releasably retained in the raise and float positions by means of the detents.

'Release of: the valve spoolsfrom the detented float positions is accomplishable manually by exertion of sufficient force on-the levers to override the detents. Release of the spools from their detented raise positions may be similarly manually effected. However, in the interest of operational efficiency it is desirable that the spools be automatically released from their detented raise position to neutral position when the associated implement actuating cylinders complete their raise or retraction strokes. V g Toth e foregoing end, the present invention provides a relatively simple, low cost detent disengaging kickout system which is now described in detail. The kickout circuitry employed to release the control valve spools from their raise detent positions comprises a relief valve 39 connected to pump 11 by means of a-line 41 and connected to return line 22 by means of a line 42. Line 42 contains a pair of spaced-

apart orifices

43 and 44, and a hydraulic kick-out cylinder 46 is coupled to a point of the line intermediate the orifices. The piston rod 47 of the kick-out cylinder is resiliently loaded to a normal retracted position by means of a spring 48, and is extended from normal position in response to the delivery of pressurized fluid thereto.

Orifice 43 restricts the flow of fluid, to cylinder 46 such that the extension movement of the rod at kickout is not violent. Such orifice also serves to drop the pressure under dynamic conditions such that in the event of failure of vale 39, high pressure fluid does not reach the pilot lines and flow is restricted with a line failure in the pilot system beyond the orifice.

Orifice 44 restricts the flow of fluid back to the main system, and also serves to permit fluid to flow from cylinder 46 back to return line 22 after valve 39 shuts off. The combination of orifice 43 upstream of cylinder 46 and orifice 44 downstream therefrom cause pressure fluid to flow to the cylinder at a rate governed by the sizes of the orifices. The combination generates a pressure to activate the kick-out cylinder when the pressure setting of relief valve 39 is reached. Such valve is set to operate at a pressure level somewhat below the pressure level of the system relief valve 26. For example, if the system relief valve is set at 2,000 psi, relief valve 39 is set at a value of approximately 1,750 psi.

The trip pressure level of relief valve 39 is reached when all energized ones of the

implement actuating cylinders

27, 28 and 29 reach the ends of their raise strokes, the system pressure building .up at this time. In other words, the trip pressure level of valve 39 is set to substantially correspond to the actuating cylinder pressure existing at the end of their raise strokes, at which time the kick-out cylinder is responsively actuated.

It is to be noted, however, that since

valves

16, 17 and 18 are connected in series, if more than one actuating cylinder is being retracted, then both, or all three cylinders must reach the ends of their strokes before pressure is built up sufficiently in line 41 to open valve 39 and actuate the kick-out cylinder.

In order to release the

controlvalves

16, 17 and 18 from their detented raise positions responsive to actuation of kick-out cylinder 46, the rod 47 of thelatter is coupled to the

valve spools

31,32 and 33 in the manner illustrated in FIGS. 2 and 3. More particularly, the con"- trol valves are mounted within a housing 49 with the upper ends of the

spools

31, 32 and 33 projecting iupwardly.

The

levers

34,36 and 37 are pivotal about a transverse shaft 51 mounted by means of blocks 35and 40 within the housing in overlying relation to the control valves. The levers include operating shafts 52, 53, and 54 projecting upwardly through slots in the top wall of the housing from bell cranks 56, 57 and 8- pivotal about shaft 51 and having crank arms'59, 61 and 62

overlying spools

31, 32 and 33. Crank

arms

59,61 and 62 are connected to'the spools 31, 32 and 33 by means of depending

links

63, 64 and 66 pivotally connected at one end to intermediate points of the crank arms and at the other end to the projecting ends of the spools. Thus,

and 62 so as to be engageable'therewith when the bail is upwardly pivoted.

The arm 67 is secured to one side 69 of the bail at'a position displaced from its pivot point about shaft 51, whereby extension of rod 47 of the kick-out cylinder effects the above-noted upward pivotal 'movement of the bail into engagement with the crank arms'59, 61 and 62. Thus, when the kick-out cylinder 46 is actuated in the manner previously described due to the system pressure existing when all energized ones of the

actuating cylinders

27, 28 and 29 have completed a raise stroke, the bail engages the crank arms associated with those valves having their spools in the detented raise position to thereby pivot the arms upwardly and translate the spools to their neutral positions.

It is important to note that the bail 68 is arranged to contact the projecting tips of the crank arms ,in sequence. More particularly, as best shown in FIG. 2, the web 72 of the bail is provided with blocks 73 and 74 of varied thickness positioned to engage the crank

arms

61 and 62 of the operating levers 36 and 37 coupled to the spools of control valves 17 and 18. All levers and control valves are depicted in FIG. 2 as being in their detented raise positions at which time the thickest block 74 contacts crank arm 62, the block 73 is spaced 46, when extending, works against only one detent at a actuating cylinder at or very near to the setting of the main relief valve 26.

It will be appreciated that when the control valves have been released to their neutral positions, fluid flow is directly from the supply line to the return line such that the system pressure drops and valve 39 is returned to its closed position. Spring 48then returns rod 47 of kick-out cylinder 46 to its normal retracted position preparatory to initiation of a subsequent kick-out cycle of operation.

Although the invention has been hereinbefore describedand illustrated in the accompanying drawings with respect to a single preferred embodiment, it will be appreciated that numerous modifications and changes may be made therein without departing from the true spirit and scope of the invention, and thus it is not intended to limit the invention except by the terms of the appended claims.

What is claimed is:

1. In a hydraulic circuit including a source of pressurized hydraulic fluid, a plurality of work implement actuating hydraulic cylinders, and a plurality of implement control valves serially connected between said source and a return line and correspondingly coupled in controlling relation to said cylinders, each of said valves having a spool selectively translatable between a plurality of flow control positions including an implement actuation position and a neutral position, said spool in said implement actuation position communicating opposite ends of the corresponding one of said cylinders to said source and said return line to effect a stroke of said cylinder, said spool in said neutral position communicating said source with said return line and blocking communication to the opposite ends of the corresponding one of said cylinders, said valves including means detenting said spools in said implement actuation positions thereof, an improved detent disengaging system comprising pressure sensitive valve means coupled between said source and a second return line communicated with said first return line, said pressure sensitive valve means being arranged to communicate said source with said second return line in response to a predetermined pressure substantially corresponding to that existing when said cylinders have completed an implement actuation stroke, a hydraulic kick-out cylinder communicably connected to said second return line for actuation responsive to the establishment of communication between said source and said second return line by said pressure sensitive valve means, and mechanical linkage means coupling said kick-out cylinder to said spools of said control valves for translating same from said implement actuation positions to said neutral positions thereof responsive to actuation of said kick-out cylinder.

2. The combination of claim 1, further defined by said second return line containing a pair of spacedapart orifices, said kick-out cylinder being communicably connected to said second return line at a point intermediate said orifices.

3. The combination of claim 1, further defined by %iv% 2l?8u fi82llal{%fli'fi fiafiit figvili lfi operating lever and crank arm projecting therefrom, a plurality of links correspondingly coupling said arms of said cranks to said spools for translating said spools between said positions thereof responsive to pivotal movement of said cranks, said cranks having implement actuation and neutral pivotal positions corresponding to said implement actuation and neutral positions of said spools, and a bail pivotally mounted on said shaft and engageable with said crank arms upon pivotal movement of the bail to pivot said cranks from said implement actuation to said neutral positions thereof, said piston rod of said kick-out cylinder coupled to said bail to efiect said pivotal movement thereof responsive to actuation of said kick-out cylinder.

4. The combination of claim 3, further defined by said second return line containing a pair of spacedapart orifices, said kick-out cylinder being communicably connected to said second return line at a point intermediate said orifices.

5. The combination of claim 3, further defined by said bail having staggered contact points for engaging said crank arms in sequence.

6. The combination of claim 5, further defined by said pressure sensitive valve means comprising a relief valve, and said second return line containing a pair of spaced-apart orifices, said kick-out cylinder being communicably connected to said second return line at a point intermediate said orifices.

7. The combination of claim 5, further defined by said bail having a plurality of blocks of varied thickness defining said staggered contact points.

8. The combination of claim 3, further defined by said bail having opposite sides pivotal about said shaft and an interconnecting web, an arm pivotally connected to said piston rod of said kick-out cylinder and rigidly secured to one side of said bail at a point displaced from the pivot axis thereof about said shaft, and a plurality of blocks of varied thickness carried by said web for engaging said crank arms in sequence upon said pivotal movement of said bail.

9. The combination of claim 8, further defined by said pressure sensitive valve means comprising a relief valve, and said second return line containing a pair of spaced-apart orifices, said kick-out cylinder being communicably connected to said second return line at a point intermediate said orifices.

Claims

2. The combination of claim 1, further defined by said second return line containing a pair of spaced-apart orifices, said kick-out cylinder being communicably connected to said second return line at a point intermediate said orifices.

3. The combination of claim 1, further defined by said linkage means comprising a plurality of bell cranks pivotal about a fixed shaft, each bell crank having an operating lever and crank arm projecting therefrom, a plurality of links correspondingly coupling said arms of said cranks to said spools for translating said spools between said positions thereof responsive to pivotal movement of said cranks, said cranks having implement actuation and neutral pivotal positions corresponding to said implement actuation and neutral positions of said spools, and a bail pivotally mounted on said shaft and engageable with said crank arms upon pivotal movement of the bail to pivot said cranks from said implement actuation to said neutral positions thereof, said piston rod of said kick-out cylinder coupled to said bail to effect said pivotal movement thereof responsive to actuation of said kick-out cylinder.

4. The combination of claim 3, further defined by said second return line containing a pair of spaced-apart orifices, said kick-out cylinder being communicably connected to said second return line at a point intermediate said orifices.