GB1604616A

GB1604616A - Remote control mechanisms

Info

Publication number: GB1604616A
Application number: GB24878/77A
Authority: GB
Original assignee: Teleflex Morse Ltd
Current assignee: Teleflex Morse Ltd
Priority date: 1977-06-14
Filing date: 1977-06-14
Publication date: 1981-12-09
Also published as: DE7817226U1; SE434891B; IT1109594B; FR2394849B1; DE2825178C2; FR2394849A1; SE7806235L; DE2825178A1; IT7868376A0

Description

(54) REMOTE CONTROL MECHANISMS (71) We, TELEFLEX MORSE LIMITED, a British company, of Christopher Martin Road, Basildon, Essex, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to remote control mechanisms and more particularly to control boxes therefor.

According to the invention there is provided a control box comprising a control member, an axially movable rod, link means pivotally connected to said rod and to said control member operatively to connect said rod with said control member, and a compression spring means mounted about said rod and between a pair of spring abutment members of which a first one will move with said rod as said rod moves axially in one direction in response to an operating movement of said control member from a predetermined position and of which the second one is retained at that time from movement with said rod so that said spring means is compressed between said abutment members and acts through said first abutment member to exert a return bias upon said rod and hence said control member, said second abutment member moving with said rod as said rod moves axially in the opposite direction from said predetermined position in response to another operating movement of said control member and said first abutment member being restrained at that time from movement with said rod so that said spring means is compressed between said abut ment members and acts through said second abutment member to exert a return bias upon said rod and hence said control member.

The invention also includes a remote control mechanism comprising a control box as aforesaid, an element which is spring biased to a predetermined position, and a push-pull cable means operably connected at one end to said axially movable rod and operably connected at the opposite end to the element such as to transfer operative motion of the former to the latter, said predetermined position of said control member corresponding to said predetermined position of the element and said compression spring means acting to bias said control member to its said predetermined position supplementing the spring loading biasing the element to its said predetermined position so that the total spring loading acting to bias the element will be shared between that latter spring bias and the spring bias applied by said compression spring means to said control member.

Preferably, the control member comprises an operator lever mounted to pivot in opposite senses about a single axis so that pivotal motion of the lever in one sense moves said rod axially in said one direction and pivotal motion of the lever in the opposite sense moves said rod axially in said opposite direction.

Flexible remote push-pull cable systems are prevalent to transmission losses in terms of movement and load such that if the remote load being controlled is locked, backlash due to manufacturing clearances will give lost motion at the operator lever. In a vibratory environment, such as can be excited by diesel engines, such lost motion can cause the operator lever to rattle.

If the cable system is used to control a spring centered spool valve, then load at the spool valve is magnified along the cable path due to frictional losses between the cable core and its guide conduit so that the effort required to be exerted at the operator lever is greater than the load at the valve end of the system.

If the spring centering load was placed entirely at the operator end, then the centering effort would be diminished along the cable path and become less at the hydraulic valve.

The backlash, previously at the operator, would now be noticeable at the valve.

To overcome these problems, we propose in one preferred embodiment of the invention to share . . . desirably substantially equally the spring centering load on the spool valve between the operator end and the valve end of the system. This has the effect of reducing the overall lever effort required to accurately centre the hydraulic valve and, at the same time, masks the backlash in the system so that it cannot be detected by the user.

When the "spring shared" system is applied to a proprietory hydraulic spool valve, such valve would need to incorporate a softer spring than is conventional.

Systems are known incorporating a motion reducing lever at the hydraulic valve so that cable travel is three or four times as long as the valve stroke, and, in this case, backlash in the cable is an insignificant proportion of the total stroke. Use, though, of such a longer stroke cable system results in bulky components producing attendant accommodation difficulties.

This "size" problem is not obtained with our spring centering load sharing solution which also has the advantage that connection of the control cable at the hydraulic valve end is more compact, easier to seal and more able to resist abuse than in the motion reducing system.

The remote control mechanism of the embodiment of the invention at present preferred is designed to enable a hydraulic valve, positioned in a location remote from the cab of a vehide and incorporated in a hydraulic circuit serving to operate, hydraulically, means associated with the vehicle or an implement carried or towed by the vehicle, to be operated mechanically through push-pull cable means by an operator in the driver's cab of the vehicle.

Thereby, the hydraulic circuit is spaced remote from the driver's cab, and the advantages attendant upon the use of cable control systems are obtained, that is to say the simplicity of such systems, their lightness, and the ease by which they can be sealed around to screen off the transmission of noise.

As will appear, the push-pull control cable means may comprise a pair of push-pull cables, one being directly coupled to a control box located in the driver's cab, and the other being directly connected to the hydraulic valve.

There is provided a quickly detachable coupling for operatively connecting and disconnecting the two cables relative to each other. Such a coupling may be conveniently mounted on a structure defining a wall of the driver's cab. The advantage of the "split" push-pull cable construction applies particularly to the instance where the hydraulic circuit operates an implement since the use of different implements with the same vehicle can be accomplished without the need to disturb the push-pull control cable mechanism as located within the driver's cab. Rather, the connection and disconnection of the input and output cables takes place outside the cab with the half of the quickly detachable coupling associated with the "changed" output cable being fitted to and disassembled from th input coupling half which can be "permanently" secured to the driver's cab.

It is to be noted that when the input and output cables are disconnected from one another, the centering spring acting on the spool valve will return that valve to neutral and the associated cable core to a position to suit, and the centering spring acting on the operator lever will likewise return that lever to neutral and its associated cable core to a corresponding neutral position, with the result that the cores of the input and output cables are matched for proper connection by the detachable coupling. It is particularly a feature of that coupling that it will connect the two cables together without disturbing the matched positions of the respective cable cores so that when so coupled, the operator lever will be in neutral when the spool valve is in neutral.

The quickly detachable coupling is optional, and the control cable could be continuous from the control box to the control hydraulic valve, rather than being of "broken" construction. Also, the quickly detachable coupling could be incorporated in a cable system not embodying the concept of the spring centering loading being shared between the valve and the operator ends of the system.

The hydraulic circuit, operated mechanically by the remote control mechanism, could be for controlling movement of hydraulic rams on public works or farm machinery, such as tractors, to operate conventional implements some examples of which are trenching, excavating, ditching and hedgecutter attachments, all of which are operated by a power arm mounted on the tractor and which can also be used, for example, to pull trailers and serve as a loader.

Further features and advantages of the invention will appear from the following description of two preferred embodiments thereof, which are given by way of example, when read in conjunction with the accompanying drawings, in which: Figure 1 is a pictorial side elevation of a remote control mechanism when incorporating a quickly detachable coupling; Figure 2 is a sectioned side elevation of a control box of the same remote control mechanism; Figure 3 is a sectioned side elevation showing the connection of an output control cable of the same remote control mechanism to a hydraulic valve; Figure 4 is a fragmentary end elevation taken in the direction of arrow A of Figure 3; Figure 5 is a sectioned side elevation through the quickly detachable coupling shown in Figure 1; Figure 6 is a sketch showing, in end elevation, the means locating the two halves of the same quickly detachable coupling relative to one another; Figure 7 is a sectioned side elevation through an alternative and preferred quickly detachable coupling for use in the remote control mechanism of Figure 1; and Figure 8 is an end elevation sketch corresponding to Figure 6 but of the coupling depicted in Figure 7.

Referring first to Figure 1, a remote control mechanism, generally indicated by the reference numeral 1, includes a control box 2 positioned in the driver's cab 3. Input and output pushpull control cables 4 and 5 respectively have their adjacent ends connected by a quickly detachable coupling 6 and their respective distant ends connected to the control box 2 and a hydraulic valve 7.

The control box 2, shown best in Figure 2, has an operator lever 81 spring centred by a compression spring 95 to a median or neutral position, to which it is returned from either direction of travel, so as to correspond to the neutral position of the hydraulic valve.

The operator lever 81 is fast with a block 82 which is mounted for pivotal movement in either sense within a housing 83 formed by a pair of housing halves secured together.

To that end, the block 82 is fast with a horizontal pivot pin 84 journalled for rotation in those housing halves. The block 82 is slotted at 85, and a short link 86 has one end mounted by a horizontal pivot pin 87 with that slot and its other end mounted by a horizontal pivot pin 88 within the slotted end 89 of an operating rod 90 which is mounted for vertical movement within the housing halves. Shifting of the operator lever 81 to the left as viewed in Figure 2 will transmit via the link 86 an upward force to the rod 90 thereby to translate the rod upwardly. Conversely, shifting of the operator lever 81 to the right will transmit via the link 86 a downward force to the rod 90 to translate the rod downwardly.

The operating rod 90 has its lower end connected to the translatable core 19 of the input control cable 4 whose casing 20 is fixed against movement . . . both by means to be described, so that pivotal motion of the operator lever 81 will translate the cable core in one direction or the other and so actuate the hydraulic valve 7.

The operating rod 90 is mounted for sliding vertical movement in the housing halves within a pair of upper and lower abutment members 91 and 92 respectively which are themselves seated in the housing halves. Circlips 93 and 94 are carried by the rod 90 to abut, in the central position of the operator lever 81, the top and bottom respectively of the upper and lower abutment members 91 and 92. Mounted about the rod 90 is the aforementioned compression spring ... referenced 95 . . . whose ends seat against the abutment members 91 and 92.

By the arrangement described, upward and downward travel of the operating rod 90 effects compression of the spring 95 so that pivotal movement in either sense from Neutral under manual control of the operator lever 81 takes place against a spring bias. Thereby, when the manual load on the lever 81 is released, the lever will be returned by the spring 95 to its central, or neutral, position.

More precisely, when the operating rod 90 moves downwardly, the upper circlip 93 urges the upper abutment member 91 downwardly thereby to compress the spring 95 against the lower abutment member 92 which, itself, is seated in the housing so as to be prevented from downward movement. Similarly, upward travel of the operating rod 90 causes the lower circlip 94 to urge the lower abutment member 92 upwardly, with the result that the spring 95 is compressed against the upper abutment member 91 which is restrained by its seating in the housing halves from upward movement.

Means are provided for limiting the degree of travel of the operating rod 90 and hence the operator lever 81. The means comprise a pair of lugs 96 on the lower abutment member 92 which slide in vertical slots 97 in the housing, and a pair of lugs 98 (displaced through 90" relative to the lugs 96) on the upper abutment member 91 which slide in vertical slots 99 in the housing. Thus, the degree of travel available to the operating rod is govemed by the lengths of the slots 97 and 99, and by varying the length of one set of slots relative to the other the lever 81 can be arranged to pivot further in one sense from neutral than the other and hence actuate the hydraulic valve further in one direction which may be desirable in certain applications.

The cable casing 20 is affixed as by swaging to a hollow hub 100 which is mounted in the halves of the housing 83 as by cotter bolts 101 which makes for positive securement. The cable core 19 is affixed as by swaging to a rod 102 whose upper end terminates in an enlarged head 103. The head 103 fits within a threaded hole 104 in the lower end of the operating rod 90. A bush 105 is slidably mounted on the rod 102 to screw into the hole 104 and so trap the head 103 therein. The bush 105 has a polygonal end 106 so that purchase thereon can be obtained with a spanner. With this construction, the cable core 19 can be readily connected (and disconnected from the operating rod 90 by pivoting the operator lever 81 to urge the rod 90 so that its lower end projects outwardly from the housing 83 at which time the rod head 103 can be inserted into the hole 104, the bush 105 threaded by hand into the same hole and then turned home by a spanner.

The control box 80 provides for demounting from the vehicle cab by carrying a blade spring 107 having a central dimple 108 and having its ends mounted in recesses 109 in an angled wall of the housing 83. A stud plate 110 is secured to the cab and is fashioned to be received in recesses 111 in the same housing wall and receive at its central aperture 112 the spring dimple 108. The arrangement is such that the control box can be slid downwardly upon the stud plate 110, and the blade spring 107 will bear against the plate to prevent rattling. As will be appreciated, the construction described provides for mounting the control box 80 to an angled wall of the cab. Mounting of the control box to a vertical cab wall 13 is also provided for by the opposite vertical face 113 of the housing 83 having similar recesses 109 and 111.

The housing 83 is sealed at its top end by a flexible rubber boot 114 which snaps over the upper end walls of the housing halves and also seals against the operator lever 81.

The connection of the output control cable 5 to the hydraulic valve 7 is shown best in Figures 3 and 4. A core 26 of the cable 5 has affixed to it, as by swaging, a post 27 which is connected by a cross-pin 28 to a shoulder bolt 29 screwed into a spool valve stem 30 of the hydraulic valve 7. A casing 31 of the cable 5 has a tube 32 made fast upon it, as by swaging, the tube being clamped within a tubular housing 33 secured as by screws 34 to a valve body 35 of the hydraulic valve 7. The housing 33 has relatively small and large diameter sections 36 and 37 respectively. The tube 32 is secured within the small diameter section 36 which also receives the core 26 and the post 27, with the shoulder bolt 29 extending into the large diameter section 37 from which wingpieces 38 extend, through which the screws 34 pass into the valve body 35.

Within the larger housing section 37 is arranged a helical compression spring 39 which is trapped between, and thus urges apart, a pair of cup washers 40 and 41, the former thus being biased against the valve body 35 and the end face 42 of the valve stem 30, and the latter being biased against an internal shoulder 43 of the housing 33 and a shoulder 44 of the bolt 29. Thereby, a seal is provided both against entry of extraneous matter between the linearly movable valve stem 30 and the valve body 35 and also into the small housing section 36 and thence between the core 26 and its casing 31.

The tube 32 is clamped within the smaller diameter section 36 of the tubular housing 33 by that section being of split construction at one end to provide a pair of lugs 45 which are urged together by a pinch bolt 46. When the pinch bolt is loosened sufficiently, the tube 32 can be slid within the housing section 36. When assembling the remote control mechanism, the tube 32 is left free to slide until the cable core 26 settles itself in its position corresponding to the neutral position of the hydraulic valve under the bias of the usual centering spring S which acts on the valve stem 30, and the tube is then clamped within the housing section 36 by tightening the pinch bolt 46.

The quickly detachable coupling 6 which connects together the adjacent ends of the control cables 4 and 5 is best shown in Figures 5 and 6. The coupling comprises a pair of coupling halves 47 and 48, the former being fixed to the vehicle cab, and the latter being detachably coupled to the fixed coupling half.

The coupling halves 47 and 48 include respective body members 50 and 51 which are cut back respectively below and above a horizontal plane passing through the longitudinal axis of the coupling so that they 'interlock' with one another as shown in Figure 1.

The body member 50 is bolted at suitable locations, one such bolted location being shown at 52, to the wall 49 of the vehicle cab. The body members 50 and 51 have similar stems 53 and 54 respectively. The stem 54 is affixed, as by swaging, to the output casing 31, and the stem 53 is likewise affixed to the input cable casing 20. A rod 55 is slidably mounted in a bore 56 within the stem 54 and is affixed, as by swaging, to the output cable core 26.

Similarly, a rod 57 is slidably mounted in a bore 58 within the stem 53 and is affixed, as by swaging, to the input cable core 19.

Seals 59 and 60 are housed in the respective stems 53 and 54 to make sealing contact with the respective sliding rods 57 and 55.

The rods 55 and 57 are fashioned similarly to their respective body members 51 and 50 so as to 'interlock' with one another. A peg 61 depends from the rod 57 and engages in a vertical aperture 62 in the rod 55, thereby to operably secure the input and output cable cores together. The rods 55 and 57 are held aligned relative to each other about their mutual longitudinal axis by each carrying a radial peg 55a or 57a engaging an axial groove 55b or 57b, respectively, formed in the respective body member 51, 50. Similarly a pair of locating pins 63 depend from the protruding section of the fixed body member 50 on either side of the peg 61, and the locating pins are received in locating apertures 63a in the protruding section of the detachable body member 51; thereby, the input and output cable casings are secured together. The arrangement is such that the detachable coupling half 48 may be detached from the fixed coupling half 47 by being moved downwardly so as to free the rod 55 and the body member 51 from the peg 61 and the locating pins 63, respectively.

To prevent such detatchment until required, a latch bolt 64 is provided which is axially slidably mounted in the body member 51 and biased towards the body member 50 by a spring 65. The latch bolt 64 has a pull ring 66 at one end and an integral latch member 67 at the other which enters a bore 68 in the body member 50 thereby to latch the detachable coupling half 48 to the fixed coupling half 47. The latch member 67 has a ramp surface 69, and a complementary surface 70 is provided on a stop member 71 mounted in the bore 68, by which to facilitate entry of the latch member into the bore.

To detach the detachable coupling half 48, the latch bolt 64 is withdrawn to free the latch member 67 from the bore 68, at which time the detachable body member 51 can be slid downwardly off the locating pins 63, this movement also serving to slide the rod 55 off the peg 61. Thus, the core and the casing of the output cable are simultaneously disconnected from the core and the casing, respectively, of the input cable.

The alternative quickly detachable coupling 6A shown in Figures 7 and 8 is similar to that just described and only those constructional features of note which are different therefrom will be discussed. The like parts in the two constructions are denoted by like reference numerals.

In the preferred couplings 6A, the longitudinal axes of the rods 55 and 57 are misaligned. Instead of those rods beieng engaged to each other by a cooperating peg and aperture, each has an annular groove 55A, 57A defining an annular head 55B, 57B respectively at the end of the respective rod 55, 57. The head 55B engages in the groove 57A and behind the head 57B, and the head 57B engages in the groove 55A and behind the head 55B. Thereby, the input and output cores are operably secured together, as before.

Another difference is that the body member 50 has but one locating pin 63 depending therefrom and fitting in a locating aperture 63a in the body member 51. The other locating pin 63 is carried by and upstanding from the body member 51 and is received in a second locating aperture 63a which is provided in the body member 50. The arrangement serves the same function as that previously described. A further difference is that the input output cable casings 31 are secured in barrel conduits 31a which are screwed into the respective body stems rather than being directly affixed thereto as before by swaging. The assembly and disassembly of the detachable coupling half 48 from the fixed coupling half 47 is carried out in the same manner as before.

When using the detachable coupling 6 or 6A, the centering spring acting on the valve stem 30 of the hydraulic valve 7 ensures that the core of the output cable is returned to the neutral position, and remains there, in the safe position until the "broken" control cable is reconnected to the control box 2 via the input cable. The control box with its centering spring 95 ensures that when the two halves of the detachable coupling are brought together for reconnection, the input core connected to the control box is also in the neutral position to match the output core connected to the hydraulic valve 7. As will be realized, each of the detachable couplings 6 and 6A when being connected to interconnect the input and output cables does so without disturbing the positions to which the input and output cores have been biased by their respective springs, and so ensures that the two cables are connected to one another with the operator lever in the correct operating position relative to that of the spool valve of the hydraulic valve.

The control box 2 can, of course, be used with either of the quickly detachable couplings 6 and 6A. Alternatively, the control box 2 can be used with an "unbroken" control cable, and is constructed so as to be demountable from the vehicle cab so as to be useable on different vehicles.

The described remote control mechanism provides for direct connection of the control cable to the hydraulic valve which is compact, comparatively easy to seal and able to resist abuse, and the control box is of relatively compact construction and has the further advantageous feature that it takes up backlash.

Attention is drawn to our copending patent application No. 36241/77 (Serial No.

1,604,617) and No. 8101520 (Serial No.

1,604,618) which disclose and claim a control box constructed similarly to that herein described and illustrated.

WHAT WE CLAIM IS: 1. A control box comprising a control member, an axially movable rod, link means pivotally connected to said rod and to said control member operatively to connect said rod with said control member, and a compression spring means mounted about said rod and between a pair of spring abutment members of which a first one will move with said rod as said rod moves axially in one direction in response to an operating movement of said control member from a predetermined position and of which the second one is restrained at that time from movement with said rod so that said spring means is compressed between said abutment members and acts through said first abutment member to exert a return bias upon said rod and hence said control member, said second abutment member moving with said rod as said rod moves axially in the opposite direction from said predetermined position in response to another operating movement of said control member and said first abutment member being restrained at that time from movement with said rod so that said spring means is compressed between said abutment members and acts through said second abutment member to exert a return bias upon said rod and hence said control member.

2. A control box as claimed in claim 1, wherein said control member comprises a lever mounted to pivot about a single axis, said firstmentioned operating movement of said control member being a pivotal movement of said lever in one sense about said single axis, and said second-mentioned operating movement of said

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. bore 68, by which to facilitate entry of the latch member into the bore. To detach the detachable coupling half 48, the latch bolt 64 is withdrawn to free the latch member 67 from the bore 68, at which time the detachable body member 51 can be slid downwardly off the locating pins 63, this movement also serving to slide the rod 55 off the peg 61. Thus, the core and the casing of the output cable are simultaneously disconnected from the core and the casing, respectively, of the input cable. The alternative quickly detachable coupling 6A shown in Figures 7 and 8 is similar to that just described and only those constructional features of note which are different therefrom will be discussed. The like parts in the two constructions are denoted by like reference numerals. In the preferred couplings 6A, the longitudinal axes of the rods 55 and 57 are misaligned. Instead of those rods beieng engaged to each other by a cooperating peg and aperture, each has an annular groove 55A, 57A defining an annular head 55B, 57B respectively at the end of the respective rod 55, 57. The head 55B engages in the groove 57A and behind the head 57B, and the head 57B engages in the groove 55A and behind the head 55B. Thereby, the input and output cores are operably secured together, as before. Another difference is that the body member 50 has but one locating pin 63 depending therefrom and fitting in a locating aperture 63a in the body member 51. The other locating pin 63 is carried by and upstanding from the body member 51 and is received in a second locating aperture 63a which is provided in the body member 50. The arrangement serves the same function as that previously described. A further difference is that the input output cable casings 31 are secured in barrel conduits 31a which are screwed into the respective body stems rather than being directly affixed thereto as before by swaging. The assembly and disassembly of the detachable coupling half 48 from the fixed coupling half 47 is carried out in the same manner as before. When using the detachable coupling 6 or 6A, the centering spring acting on the valve stem 30 of the hydraulic valve 7 ensures that the core of the output cable is returned to the neutral position, and remains there, in the safe position until the "broken" control cable is reconnected to the control box 2 via the input cable. The control box with its centering spring 95 ensures that when the two halves of the detachable coupling are brought together for reconnection, the input core connected to the control box is also in the neutral position to match the output core connected to the hydraulic valve 7. As will be realized, each of the detachable couplings 6 and 6A when being connected to interconnect the input and output cables does so without disturbing the positions to which the input and output cores have been biased by their respective springs, and so ensures that the two cables are connected to one another with the operator lever in the correct operating position relative to that of the spool valve of the hydraulic valve. The control box 2 can, of course, be used with either of the quickly detachable couplings 6 and 6A. Alternatively, the control box 2 can be used with an "unbroken" control cable, and is constructed so as to be demountable from the vehicle cab so as to be useable on different vehicles. The described remote control mechanism provides for direct connection of the control cable to the hydraulic valve which is compact, comparatively easy to seal and able to resist abuse, and the control box is of relatively compact construction and has the further advantageous feature that it takes up backlash. Attention is drawn to our copending patent application No. 36241/77 (Serial No. 1,604,617) and No. 8101520 (Serial No.

control member being a pivotal movement of said lever in the opposite sense about said single axis.

3. A control box as claimed in claim 2, including a housing providing seatings for said spring abutment members, a first urging means carried by said axially movable rod to urge, upon axial movement of said rod in said one direction, said first abutment member to move away from its seat and with said rod to compress said spring means against said second abutment member which seats, at that time, in said housing thereby to be restrained against axial movement in said one direction with said rod, and a second urging means carried by said axially movable rod to urge, upon axial movement of said rod in said opposite direction, said second abutment member to move away from its seat and with said rod to compress said spring means against said first abutment member which seats, at that time, in said housing thereby to be restrained against axial movement in said opposite direction with said rod.

4. A control box as claimed in claim 3, wherein said lever is pivotally mounted by a pivot pin to said housing.

5. A control box as claimed in daim 3 or claim 4, wherein each of said urging means comprises a circlip.

6. A control box as claimed in any of claims 3 to 5, including means for limiting the degree of axial travel available to said axially movable rod.

7. A control box as claimed in claim 6, wherein said limiting means are associated with said housing and said axially movable rod.

8. A control box as claimed in any of daims 3 to 7, including mounting means by which to be detachably mounted in position.

9. A control box as claimed in claim 8, wherein said mounting means comprises a stud plate slidably received in said housing and prevented from rattling therein by a blade spring.

10. A control box as claimed in any of the preceding daims, wherein said axially movable rod is slidably mounted in said spring abutment members.

11. A remote control mechanism comprising a control box as claimed in any of the preceding claims, an element which is spring biased to a predetermined position, and a push-pull cable means operably connected at one end to said axially movable rod and operably connected at the opposite end to the element such as to transfer operative motion of the former to the latter, said predetermined position of said control member corresponding to said predetermined position of the element and said compression spring means biasing said control member to its said predetermined position supplementing the spring loading biasing the element to its said predetermined position so that the total spring loading acting to bias the element will be shared between that latter spring bias and the spring bias applied by said spring means to said control member.

12. A remote control mechanism as claimed in claim 10, including a housing means which is fixed to a body with respect to which said element is movable, tube means within which the casing of said cable means at said opposite end thereof is secured against movement, means for clamping said tube means in different longitudinal positions within said housing means, and means for connecting the core of said cable means at said opposite end thereof within said housing means to the element.

13. A remote control mechanism as claimed in claim 12, wherein said core connecting means comprise a post to which the core is secured and a headed screwthreaded member to which the post is attached, and including a pair of sealing members within said housing means and urged apart by a spring so that one seats against a shoulder of said housing means and the head of said screw threaded member and the other seats against the body and the element.

14. A remote control mechanism as claimed in any of claims 11 to 13, wherein said pushpull cable means comprise input and output push-pull cables having the distant end of the input cable operably connected to said control member and the distant end of the output cable operably connected to the element, and wherein said mechanism further comprises a releasable coupling connectable operably to interconnect the proximal ends of said input and output cables without disturbing the matched positions assumed by the respective cores thereof under the influence of the respective spring bias applied to the control member and the element.

15. A remote control mechanism as claimed in claim 14, wherein said releasable coupling comprises a pair of coupling halves a first one of which has means by which to be fixed in position, said first coupling half having a body member affixed to the cable casing of said input cable at the proximal end thereof, said first coupling half also having a longitudinally sliding member within its said body member and affixed to the core of said input cable at 5aid proximal end thereof, a second of said coupling halves having a body member affixed to the cable casing of said output cable at the proximal end thereof, said second coupling half also having a longitudinally sliding member within its said body member and affixed to the cable core of said output cable at said proximal end thereof, means for detachably interconnecting said body member of said second coupling half to said body member of said first coupling half by which to interconnect in predetermined relative positions said cable casings of said input and output cables, and means for detachably interconnecting said longitudinal sliding members of said first and second coupling halves by which operably to interconnect in predetermined relative positions said cable cores of said input and output cables.

16. A remote control mechanism as claimed in claim 15, wherein said means for detachably interconnecting said body members and said means for detachably interconnecting said longitudinal sliding members permit said body members and said longitudinal sliding members to be simultaneously interconnected and disconnected by which the casing and the core of the output cable are simultaneously interconnected and disconnected to and from the casing and the core of the input cable.

17. A remote control mechanism as claimed in claim 16, wherein said means for detachably interconnecting said body members and said means for detachably interconnecting said longitudinal sliding members are such that those members are simultaneously disconnected by a radial movement relative to the longitudinal axis of the coupled coupling halves of said second coupling half with respect to said first coupling half in one direction, said members being simultaneously interconnected by a similar radial movement but in the opposite direction.

18. A remote control mechanism as claimed in claim 17, including a latch means for detachably interconnecting said body members of said first and second coupling halves to prevent said disconnection of said body members and said longitudinal sliding members whilst said latch means is operative to interconnect said body members.

19. A remote control mechanism'as claimed in claim 18, wherein said latch means comprises a latch member carried by one said body member and movable into and from engagement with a cooperating means for the other said body member.

20. A remote control mechanism as claimed in claim 19, wherein said latch member is axially slidably mounted in said one body member, and said cooperating means comprises a receiving means in said other body member adapted to receive therein said axially slidable latch member.

21. A remote control mechanism as claimed in claim 20, including spring means biasing said latch member axially towards said receiving means.

22. A remote control mechanism as claimed in any of claims 19 to 21, wherein said latch member is carried by the body member of said second coupling half, and said cooperating means is of said first coupling half.

23. A remote control mechanism as claimed in any of claims 17 to 22 wherein said means for detachably interconnecting said body members comprise cooperating peg and aperture means associated with said body members, said peg and aperture means being engaged with and disengaged from one another upon said radial movement of said second coupling half relative to said first coupling half in said opposite direction and said one direction respectively.

24. A remote control mechanism as claimed in any of claims 17 to 23, wherein said means for detachably interconnecting said longitudinal sliding members comprise cooperating peg and aperture means associated with said longitudinal sliding members, said peg and aperture means being engaged with and disengaged from one another upon said radial movement of said second coupling half relative to said first coupling half in said opposite direction and said one direction respectively.

25. A remote control mechanism as claimed in any of claims 17 to 23, wherein the longitudinal axes of said longitudinal sliding members are misaligned relative to one another, and wherein said means for detachably interconnecting said longitudinal sliding members comprise, for each said longitudinal sliding member, an annular groove therein defining a head at one end of the respective sliding member, the adjacent ends of said longitudinal sliding members being arranged to overlap one another so that the head of one such member engages in the groove of the other member and the head of said other member engages in the groove of said one member.

26. A remote control mechanism as claimed in claim 24, including means for aligning said longitudinal sliding members relative to one another so that said cooperating peg and aperture means associated therewith are mutually aligned for engagement with one another.

27. A remote control mechanism as claimed in claim 26, wherein said aligning means comprise, for each longitudinal sliding member, radial pin means and axial groove means associated with the respective longitudinal sliding member and body member and engaged with one another.

28. A remote control mechanism as claimed in any of claims 11 to 27, wherein said element is a spring centered spool valve of a hydraulically operated mechanism, said control member is positioned for operation by a driver in the cab of a vehicle, and said cable means spaces said spool valve remote from said cab.

29. Either of the remote control mechanisms as claimed in claim 11 and substantially as herein described with reference to the accompanying drawings.

30. A control box as claimed in claim 1 and substantially as herein described with reference to Figure 2 of the accompanying drawings.