US3128839A - Control devices for hydraulically ac - Google Patents

Description

April 14. 1964 A. J. BUTTERWORTH 3,128,839

CONTROL DEVICES FOR HYDRAULICALLY ACTUATED JACKING OR PARKING MECHANISM 5 Sheets-Sheet 1 Filed March 23, 1959 deems/11.0 JAM/5s Barman Mm AT-ry.

April 14, 1964 A. J. BUTTERWORTH 3,128,839

CONTROL DEVICES FOR HYDRAULICALLY ACTUATED JACKING OR PARKING MECHANISM 5 Sheets-Sheet 2 Filed March 23, 1959 AkCH/BA L o c/A/V/[S Burrzwmem ATT).

April 14, 1964 A. J. BUTTERWORTH 3,128,839

CONTROL DEVICES FOR HYDRAULICALLY ACTUATED JACKING 0R PARKING MECHANISM 5 Sheets-Sheet 5 F/Go.

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Aprll 14, 1964 A. J. BUTTERWORTH 3,128,839

CONTROL DEVICES FOR HYDRAULICALLY ACTUATED JACKING OR PARKING MECHANISM Filed March 25, 1959 5 Sheets-Sheet 4 ARM/5AM JAM; flu/ m/mem Aprll 14. 1964 A. J. BUTTERWORTH 3,128,839

CONTROL DEVICES FOR HYDRAULICALLY ACTUATED JACKING 0R PARKING MECHANISM Filed March 25, 1959 5 Sheets-Sheet 5 5 4909/5410 JA/Vf! urrmmem United States Patent 3,128,839 CGNTROL DEVICES FOR HYDRAULICALLY AC- TUATED EACKHNG R PARKING MECHANISM Archibald James Butter-worth, 7 Grove Gardens, Frirnley, near Aldershot, England Filed Mar. 23, 1959, Ser. No. 801,254 Claims priority, application Great Britain Mar. 24, 1958 3 (Ilaims. (Cl. 1801) This invention relates to a control device for hydraulically actuated jacking or parking mechanism, hereinafter referred to collectively as jacking mechanism which is carried by a vehicle and of the kind in which a hydraulic ram on each side of the vehicle may be brought into circuit by a valve mechanism with a pump driven from the vehicle engine so that ground engaging elements of the jacking mechanism may be lowered into contact with the ground thereby lifting the road wheels and particularly to such a device in which each said element comprises a roller which may be brought both into engagement with the ground and to engagement with the wheel of the vehicle so as to be rotated thereby when the vehicle wheel has been lifted and thus move the vehicle sideways. With such an arrangement it is important that the rams shall not be energised to lower the ground engaging rollers unless the vehicle is stationary or only moving at a slow speed and that the valve should be automatically returned to a position where the ram is cut olf from communication with the pump when the engine stops, rendering it impossible for the jack to be lowered when the vehicle is travelling at speed and also preventing the vehicle from being unintentionally driven away with the mechanism in its lowered position.

According to this invention a control device for hydraulically actuated jacking mechanism of the kind referred to for a vehicle is characterised in that dentent means are associated with a manually operated valve mechanism for holding the valve mechanism in a position where each ram is cut off from the pump and which detent means are arranged to be released only when a control for the speed of the vehicle is in such a position that the vehicle is stationary or only travelling at low speed and in that means are provided for automatically returning the valve mechanism to a position where the ram is cut off from communication with the pump when the engine stops.

The control for the vehicle speed may comprise a control lever or selector for a change speed gear box, and which is arranged to release the detent when the change speed gear has been adjusted to a first gear position or neutral position or reverse position.

The detent means may comprise an electromagnetic device in circuit with a source of supply and switch mechanism actuated by the vehicle speed control device.

Means dependent on the pressure in the rams may be arranged to maintain said valve mechanism in the position to which it has been brought by manual control where the ram is in communication with said pump.

The aforesaid means for automatically returning the valve mechanism to a position where each ram is cut off from communication with the pump may comprise a spring associated with a moving part of the valve mechanism and which is loaded when the mechanism is moved "ice by hand to bring the ram into communication with the pump.

The manually operated valve mechanism may comprise a rectilinearly movable slide valve which at one limit of its movement cuts off the ram from communication with the pump and places it in communication with an exhaust or with a fluid reservoir and short circuits the pump, for example, through said fluid reservoir, and in the other limit of its movement places the outlet of the pump in communication with the hydraulic ram.

The slide valve may comprise a plunger located in a cylinder having four axially spaced ports, one leading to the exhaust or reservoir and referred to as an exhaust port, another leading to the pump and referred to as a pump port and a third port between these leading to the rams referred to as the ram port and a fourth port leading to the reservoir by a filter which plunger has a first circumferential channel formed in it of such a length that at one limit it overlaps the ram port and exhaust port and at the other limit overlaps the ram port and pump port and which plunger has a second circumferential channel formed in it of such a length that at one limit it overlaps the ram port and the fourth port and at the other limit the cylindrical portion separating these two circumferential channels cuts off the ram port from the fourth port and which plunger is provided with a depression or circumferential groove engageable by said detent when the plunger is in the first of the above positions. If the exhausting oil from the rams was carried out by leading it through the same passage as the short-circuited oil from the pump there would be the danger of inadvertent operation of the mechanism due, for example, to pressure rise caused by a blocked filter. An object of separating them as set out above is to avoid this danger.

That part of the plunger and that part of the cylinder which are disposed on the side of the ram port nearer the exhaust port are smaller in diameter than the other part of the plunger and cylinder and wherein the plunger is movable against the action of a spring in a direction to cut off communication of the ram with the exhaust to a position in which the ram is brought into communication with the pump thus when the plunger is brought to this position by hand the differential pressure on the two parts .of the plunger on opposite sides of the circumferential however, the engine stops the differential pressure ceases to exist owing to leakage and the spring will bring the plunger back to a position in which the ram is brought into communication with the exhaust and it is automatically retained in this position by the detent mechanism which comes into operation as soon as the change speed mechanism is removed from first or reverse positions. The parking device will then be Withdrawn to its inoperative position by the action of its retraction springs.

A hydraulically actuated jacking mechanism for a vehicle having a control device as set out above and having a ground engaging roller on each side of the vehicle which may be brought into engagement with the ground and is then driven by a road wheel characterised in each ground engaging roller is mounted to rotate about a fore and aft horizontal axis and is driven through gearing from a driving roller which is so mounted on a part of the jacking -mechanism as to be brought into engagement with a side of a road wheel rim.

In such an arrangement the driving wheel and gearing are mounted on an arm pivotally attached to a part of the vehicle so as to swing about a fore and aft axis and each said ram has a part thereof pivoted to a part of the vehicle so as to swing about a fore and aft aXis spaced inwardly from the first said axis and another part of which ram is pivotally attached to said arm or a part secured thereto.

The aforesaid gearing may be bevel gearing.

In one construction according to the invention one of said bevelled gears and said driving roller are fixed to a tubular element which encircles a journal constituting a part of said arm and the other bevel gear and ground engaging roller are mounted on a spindle fixed at right angles to said arm.

The aforesaid arm may be pivotally mounted on a spring anchorage for one of the vehicle wheels and the first said part of the ram may be mounted on a wheel axle casing.

The aforesaid ground engaging rollers may be duplicated on each arm and the duplicated rollers may be fixed to a spindle rotatable in a bearing fixed to said arm and one of said rollers or the spindle has fixed to it a gear wheel which meshes with a gear wheel mounted on said arm and driven by said driving roller.

The duplicated ground engaging rollers are preferably axially spaced apart on said spindle on either side of a bearing fixed to said arm and the part of the arm between the rollers comprises a journal portion encircled by a tubular element to which is fixed a bevel wheel which meshes with another bevel wheel fixed to one of the rollers and which tubular element also has fixed to it said driving wheels.

The following is a more detailed description of one embodiment of the invention reference being made to the accompanying drawings in which:

FIGURE 1 is a longitudinal section through the valve control mechanism and detent mechanism, the associated parts being shown in elevation,

FIGURE 2 is a diagrammatic perspective view of the control mechanism of FIGURE 1 applied to hydraulic rams arranged to lower rollers into engagement with the ground and with the road wheels of a vehicle,

FIGURE 3 is a similar view to FIGURE 1 showing the movable valve member at the opposite limits of its travel,

FIGURE 4 is a side elevation partly in section of one form of roller engaging mechanism the movement of which can be controlled by the valve mechanism of the present invention,

FIGURE 5 is a section on the line 5-5 of FIGURE 7,

FIGURE 6 is a similar view to FIGURE 5 of an alternative arrangement,

FIGURE 7 is a section on the line 7-7 of FIGURE 4 and FIGURE 8 is a similar view to FIGURE 5 of an alternative arrangement.

In the arrangement shown in FIGURE 1, the valve mechanism comprises a cylinder 10 having four ports 11, 12, 13 and 14 formed therein which are axially spaced along the cylinder. The port 11 is provided with a coupling 9 for connecting it to a T-piece 8 which communicates with a reservoir 7 for fluid and with the inlet 6 of a pump 5. The port 12 is provided with a coupling 4 for connecting it to the hydraulic ram mechanism 60 associated with the combined vehicle jacking and sideways traversing mechanism shown in FIGURE 2. The port 13 is provided with a coupling 3 for connecting it with the outlet 2 of the pump 5. The port 14 is provided with a coupling 1 for connecting it to one side of a filter 61, the other side of which communicates with the aforesaid reservoir 7. The part of the bore 15 on that side of the port 12 nearer the port 11 is of smaller diameter than the part of the bore 16 on the other side of the port 12. Located within the bore is a plunger formed with two circumferential channels 17 and 18 leaving the plunger with three cylindrical portions 19, 29 and 21. The diameter of the portion 19 is such as to be a sliding fit in the part 15 of the bore and is thus smaller than the diameter of the other portions 20 and 21. The axial lengths of the circumferential channels 17 and 18 are such that at one limit of movement of the plunger (as shown in FIGURE 3) the ram port 12 is placed into communica tion with the exhaust port 11 and the pump port 13 is placed in communication with the port 14 leading to the filter and oil reservoir. The inlet 6 of the pump is in permanent communication with the reservoir 7 so that in this position of the valve the pump is short circuiting through the oil reservoir and filter. When the plunger is brought to the other limit of its movement as shown in FIGURE 1 the ram port 12 is cut off from communication with the exhaust port 11 and brought into communication with the pump port 13 while the port 14 is cut off from communication with the outlet 2 of the pump. Under these conditions the ram is energised and lowers the jack mechanism 60 against the action of a spring usually provided between the jack plunger and the end of the jack cylinder in the case of a single-acting hydraulic jack. The plunger is retained in the first position described above and shown in FIGURE 3 by an electromagnetically operated detent device comprising a pin 22 which is engageable with a circumferential groove 23 in the part 21 of the plunger. The pin is mounted on the armature 24 of a solenoid which is reciprocable in a coil 25 within the casing 62 which coil is arranged in circuit with a source of supply and a switch 55 and which switch can only be closed by bringing the change speed gear lever 56 or selector of a change speed gear box 57 of the vehicle either into low gear position or reverse gear position. This switch may be of a known type such as is used, for example, to operate a reversing lamp. Under these conditions the armature 24 is drawn into the coil 25 against the action of the spring 26. When so withdrawn the valve may be moved manually by means of a rod 27 which may protrude through the fire panel of the vehicle and may be fitted with a manipulating knob. The rod is connected to an extension 29 of the valve by a coupling 28. The extension 29 projects out through a cover plate 30 at the end of the aforesaid cylinder 10. A spring 31 is disposed between the cover plate and a flange 32 on the plunger. When the plunger is moved to the position shown in FIGURE 1 against the action of the spring 31 into a position in which the ram port 12 is brought into communication with the pump port 13, the differential pressure on the annular faces of the parts 19 and 20 of the plunger will retain it in the last mentioned position against the action of the spring 31 and it will remain in this position until pushed back by the driveror until the engine stops and the pump is no longer driven when it will return to the position shown in FIG- URE 3 of the drawing under the action of the spring when the projection 22 will again snap back into the groove 23. Leaking of oil along the plunger into the ends of the cylinder is prevented by two sealing rings 33, 34. It will be noted that when the plunger is at that limit of its movement which causes the ram to be actuated as shown in FIGURE 1 and a higher pressure zone exists between ports 12 and 13, i.e. in the annular space 17, such pressure cannot reach these sealing rings because such fluid as leaks past the labyrinth grooves at parts 19 and 20 of the plunger, is discharged into ports 11 and 14 which are open to atmospheric pressure. This arrangement prevents the creation of inward radial pressure against the plunger due to plastic deformation of the toroidal oil seals, under pressure, 34 and 33 with consequent friction resistance to manual or spring movement of the plunger.

The difference between the larger and smaller diam eter portions 15 and 16 of the cylinder and plunger 19 and 20 are so selected in relation to the rating of the spring 31 that when differential pressure is set up it is a little less than twice the pressure exerted by the spring so that when pushing the rod 27 in the direction to bring the parts to the position shown in FIGURE 3 there is about the same resistance to movement as when moving it in the opposite direction.

As indicated earlier in the specification the invention is particularly applicable to an arrangement in which a hydraulic ram is arranged to raise and lower a roller into engagement with the ground, which roller is driven by a track which is brought into engagement with the side or" the wheel or the wheel rim. Various forms of such an arrangement are shown in United States patent applications Serial Nos. 578,351 (now Patent No. 2,964,- 118), 667,117 (since abandoned) and 716,945 (now Patent No. 3,057,424). One form of such an arrangement is shown in FIGURES 4 to 6 Where the plunger 35 of the hydraulic ram is pivotally connected at 36 to a mounting 37 for the roller 38. The mounting is provided with a journal portion 39, the upper end of which has rotatably secured thereto an extension 40 which is pivoted at 41 to a fixed part 42 of the vehicle chassis. The journal portion is encircled by a tubular element 43 to the lower end of which is fixed a bevel pinion 44 which engages a bevel wheel 45 constituting a part of the roller frame 46. The upper end of the tubular element 43 has secured thereto a friction wheel 47 which is arranged to be brought into engagement with the wheel rim 48. The cylinder part 49 of the ram is pivotally attached at 50 to a fixed part of the chassis frame.

The arrangement shown in FIGURES 7 and 8 is similar to that described above with the exception that two ground engaging rollers 51, 52 are provided, fixed to a spindle 53 mounted in a bearing 54 in the part 37 which is pivotally connected to the ram. The roller 51 is provided with the bevel wheel 45 which is engaged by the bevel pinion 44. The journal portion 39 and the extension 40 are separately formed, the splined end of the former engaging a splined socket 63 in the latter.

I claim:

1. A control device for a parking mechanism of a motor-driven vehicle comprising a hydraulic jack having a cylinder and a piston reciprocable therein, a groundengaging roller mounted on said piston, a hydraulic pump driven by the vehicle engine for actuating said jack, a valve casing having port means disposed at spaced intervals therealong, a valve member movable within said valve casing including controlling portions thereon, resiliently yielding means disposed between said valve member and said valve casing to urge said valve member into a normally inoperative position, reservoir means for holding a hydraulic fluid, means connecting said reservoir means to said pump and said port means, means connecting said pump to said port means, means connecting said port means to said jack, said controlling portions when said valve member is in said inoperative po sition connecting said pump and reservoir means together through said port means and connecting means, manual control means operatively connected to said valve member adapted to move said valve member into and operative position against the action of said resiliently yielding means so that said controlling portions connect said pump means to said jack through said port means and connecting means to extend said piston and cause said ground-engaging roller to engage the ground to lift a part of said vehicle therefrom, one of said controlling portions when in said operative position being acted on by the pressure of the hydraulic fluid to maintain said valve member in said operative position against the action of said resiliently yielding means independently of said manual control means and in the absence of the pressure of the hydraulic fluid the action of the resiliently yielding means moves the valve member into said inoperative position, locking means for holding said valve member in the inoperative position, power means for releasing said locking means, a change-speed gear box through which the vehicle is driven and having a first gear and a reverse gear, a gear-selecting mechanism mounted in the gear box for selecting the gear to be used therein, and a control device for the power means actuated by the gear-selecting mechanism when it is moved to a position in which the first gear or reverse gear is engaged and which causes the power means to release the locking means.

2. A control device according to claim 1 wherein said locking means comprises a spring-biased detent, an electromagnetic mechanism having a coil operatively connected to said detent, said coil being in circuit with a source of electric supply constituting said power means and with a switch constituting said control device actuated by the selecting mechanism so as to release the detent when the gear-selecting mechanism is brought to a position for engaging first gear or reverse gear.

3. A control device for a parking mechanism of a motor-driven vehicle comprising a hydraulic jack having a cylinder and a piston reciprocable therein, a ground-engaging roller mounted on said piston, a hydraulic pump driven by the vehicle engine for actuating said jack, a valve casing having port means disposed at spaced intervals therealong, a valve member movable Within said valve easing including controlling portions thereon, resiliently yielding means disposed between said valvemember and said valve casing to urge said valve member into a normally inoperative position, reservoir means for holding a hydraulic fluid, means connecting said reservoir means to said pump and said port means, means connecting said pump to said port means, means connecting said port means to said jack, said control-ling portions when said valve member is in said inoperative position connecting said pump and reservoir means together through said port means and connecting means, manual control means operatively connected to said valve member adapted to move said valve member into an operative position against the action of said resiliently yielding means so that said con trolling portions connect said pump means to said jack through said port means and connecting means to extend said piston and cause said ground-engaging roller to engage the ground to lift a part of said vehicle therefrom, one of said controlling portions when in said operative position being acted on by' the pressure of the hydraulic fluid to maintain said valve member in said operative position against the action of said resiliently yielding means independently of said manual control means and in the absence of the pressure of the hydraulic fluid the action of the resiliently yielding means moves the valve member into said inoperative position, the said manually-controlled valve member comprising a plunger and said valve casing comprising a cylinder having four axially spaced ports one leading to exhaust, a second leading to the pressure side of the pump, a third disposed between the first and second of said ports leading to the hydraulic jack and a fourth leading to said reservoir means, said plunger having a first portion of reduced diameter of such length so that at one limit of its movement it overlaps the third port and the first port and at the other limit overlaps the third port and the second port, said plunger having a second portion of reduced diameter and of such length that rat a first limit of movement of the plunger it overlaps the second port and the fourth port, a cylindrical portion on said plunger separating the two reduced portions to cut oh the second port from the fourth port at the other limit of movement of said plunger, part of the plunger and part of the cylinder disposed on one side of the third port nearer the first por-t being smaller in diameter than said cylindrical portion but greater in diameter than said reduced portions, said first reduced portion connecting said cylindrical portion and said part of the plunger in spaced axial relation, and said plunger being movable against the action of said yielding means in a direction to cut off communication of the jack with the first port to a position in which the jack is brought into communication with the second port so that the differential pressure on the confronting faces of said axially spaced parts of the plunger maintains the plunger in the latter position. 5

References Cited in the file of this patent UNITED STATES PATENTS Williams et a1. Dec. 8, 1925 Williams Nov. 30, 1926 10 (US. corresponding Patent 2,964,118, Dec. 13, 1960)

Claims (1)

1. A CONTROL DEVICE FOR A PARKING MECHANISM OF A MOTOR-DRIVEN VEHICLE COMPRISING A HYDRAULIC JACK HAVING A CYLINDER AND A PISTON RECIPROCABLE THEREIN, A GROUNDENGAGING ROLLER MOUNTED ON SAID PISTON, A HYDRAULIC PUMP DRIVEN BY THE VEHICLE ENGINE FOR ACTUATING SAID JACK, A VALVE CASING HAVING PORT MEANS DISPOSED AT SPACED INTERVALS THEREALONG, A VALVE MEMBER MOVABLE WITHIN SAID VALVE CASING INCLUDING CONTROLLING PORTIONS THEREON, RESILIENTLY YIELDING MEANS DISPOSED BETWEEN SAID VALVE MEMBER AND SAID VALVE CASING TO URGE SAID VALVE MEMBER INTO A NORMALLY INOPERATIVE POSITION, RESERVOIR MEANS FOR HOLDING A HYDRAULIC FLUID, MEANS CONNECTING SAID RESERVOIR MEANS TO SAID PUMP AND SAID PORT MEANS, MEANS CONNECTING SAID PUMP TO SAID PORT MEANS, MEANS CONNECTING SAID PORT MEANS TO SAID JACK, SAID CONTROLLING PORTIONS WHEN SAID VALVE MEMBER IS IN SAID INOPERATIVE POSITION CONNECTING SAID PUMP AND RESERVOIR MEANS TOGETHER THROUGH SAID PORT MEANS AND CONNECTING MEANS, MANUAL CONTROL MEANS OPERATIVELY CONNECTED TO SAID VALVE MEMBER ADAPTED TO MOVE SAID VALVE MEMBER INTO AND OPERATIVE POSITION AGAINST THE ACTION OF SAID RESILIENTLY YIELDING MEANS SO THAT SAID CONTROLLING PORTIONS CONNECT SAID PUMP MEANS TO SAID JACK THROUGH SAID PORT MEANS AND CONNECTING MEANS TO EXTEND SAID PISTON AND CAUSE SAID GROUND-ENGAGING ROLLER TO ENGAGE THE GROUND TO LIFT A PART OF SAID VEHICLE THEREFROM, ONE OF SAID CONTROLLING PORTIONS WHEN IN SAID OPERATIVE POSITION BEING ACTED ON BY THE PRESSURE OF THE HYDRAULIC FLUID TO MAINTAIN SAID VALVE MEMBER IN SAID OPERATIVE POSITION AGAINST THE ACTION OF SAID RESILIENTLY YIELDING MEANS INDEPENDENTLY OF SAID MANUAL CONTROL MEANS AND IN THE ABSENCE OF THE PRESSURE OF THE HYDRAULIC FLUID THE ACTION OF THE RESILIENTLY YIELDING MEANS MOVES THE VALVE MEMBER INTO SAID INOPERATIVE POSITION, LOCKING MEANS FOR HOLDING SAID VALVE MEMBER IN THE INOPERATIVE POSITION, POWER MEANS FOR RELEASING SAID LOCKING MEANS, A CHANGE-SPEED GEAR BOX THROUGH WHICH THE VEHICLE IS DRIVEN AND HAVING A FIRST GEAR AND A REVERSE GEAR, A GEAR-SELECTING MECHANISM MOUNTED IN THE GEAR BOX FOR SELECTING THE GEAR TO BE USED THEREIN, AND A CONTROL DEVICE FOR THE POWER MEANS ACTUATED BY THE GEAR-SELECTING MECHANISM WHEN IT IS MOVED TO A POSITION IN WHICH THE FIRST GEAR OR REVERSE GEAR IS ENGAGED AND WHICH CAUSES THE POWER MEANS TO RELEASE THE LOCKING MEANS.

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