The present invention relates to post or pile drivers ("post drivers") The present invention recognises the prospect of conferring a measure of safety to the operator of a post driver by denying the operator the opportunity to have a free hand when die post dπvei is being operated to allow the free fall of the monkey or hammer ("monkey")

In particular although not solely the present invention relates to any of the types of post driver typified by those of our company such as exemplified in New Zealand patent numbers 532190/532239/533562, 538154 and 553592/560375, Patent applications 565198, 565236, 566515, 566677, 568942, 569029 and New Zealand registered design numbers 403615, 408782, 408783 or in our KINGHITTER™ range of postdπvers (see www fairbrotheπnd com)

Such post drivers, whether with a telescopic mast arrangement or not, usually have some measure of mechanical advantage between a hydraulic ram and the monkey such that small upwaid movements under hydraulic power of the ram system lifts the monkey furdier than does the ram system extend In some embodiments, where there is the telescopic advantage, this is exemplified In many of our postdπver ranges there is a whole variety of different hydraulically driven functionalities So much so that a bank of hydraulic valves is generally installed to be operated as and when required by the operator These additional functionalities can be to arrange tilt, arrange lean, arrange swing, etc In Australia safety requirements are designed to require a cage so that the operator is denied the opportunity to be caught between any monkey and the post or between any post cap carried by the monkey and the monkey during the driving stroke

We believe appropriate positioning of controls for the hydraulic system and a requirement that both hands be on a control during a power stroke significandy enhances the safety requirements and provides compliance that should satisfy even the stringent Australian safety requirements (whether with or without the cage)

It is therefore an object of the present invention to provide a postdπver winch has a safety enhancement in that it denies the operator to the opportunity to allow free fall to impact without both hands being employed elsewhere It is a further or alternative object of die present invention to provide control systems, techniques, uses, methods and apparatus which will at least provide for two handed operated control of a post driver during a driving stroke yet preferably does not require two handed operation for all odier functionalities whether lifting, slowly lowering or other

These objects preferably aie achieved for a hydraulic system of a post driver Such system can be to allow an exhaust from a ram system or not In other forms of hydraulic system a rotary drive can be used In still others, othei than a hydraulic system can be involved (eg, pneumatics, solenoids, etc)

In a first aspect die invention is a post or pile driving apparatus (hereafter "post driving apparatus") which is controllable by controls of a plural control input control system which, for a driving drop, requires two hands thereby ensuring an operator's hand can not be between

(i) the post or a post cap of the post driver, and

(ii) the monkey of the post driver during the drive drop of the monkey to drive the post direcdy or via the post cap.

In another aspect die invention consists in post or pile driving apparatus (hereafter "post driving apparatus") which is controllable by a two handed control system thereby ensuring an operator's hand can not be between (i) die post or a post cap of the post driver, and (ii) the monkey of the post driver during the drop of the monkey to drive die post direcdy or via the post cap.

Preferably die arrangement involves hydraulic controls Such controls can be button or lever operated (preferably lever)

A most preferred embodiment is one where it is not possible to drop die monkey at driving speed to a post (or the post cap on the post) widiout each of the operator's hands being on one of the two controls A low speed drop of die monkey preferably is possible using only one hand of the operator. This low speed drop is to allow alignment of the monkey with the post and/or the alignment of die post to the post cap and/or monkey.

In anodier aspect die invention consists in post driving apparatus of a kind dependent on a hydraulic ram to raise the monkey (preferably dirough a mechanical advantage) for an ensuring drop; wherein diere is a provision to dump hydraulic fluid from the ram into the hydraulic circuit to allow the drop of the monkey, and wherein interactive valvmg or some equivalent arrangement requires both hands of the operator to be employed on valve and/or other actuator(s) to allow die driving drop.

Preferably two valves separately require separate hand actuation to allow a sufficient exhaust via an exhaust padiway to achieve a driving speed. Preferably the functionality of interactive valves or like functionalities is such as to allow, with one hand, a low speed lowering of the monkey

Preferably such low speed lowering is allowed by a reduced exhaust flow of die hydraulic fluid from die hydraulic ram In yet a further aspect the present invention consists in a post driving apparatus having a hydraulic system to raise the monkey (whether with or without telescopic extension of the mast or part thereof), wherein two controls, one for each hand of an operator, must be actuated to allow a faster exhaust of hydraulic fluid which allows die monkey drop than is the case where one only of die controls actuated by a single hand of die operator.

In yet a further aspect the invention consists in postdriving apparatus substantially ab herein descπbed with or without reference to any one of die accompanying drawings

In yet a further aspect die present invention consists in the safety functionality defined previously

In still a further aspect the present invention consists in a method of protecting an operator's hands when operator a postdriver, said method comprising the steps of ensuring both hands of die operator are needed on controls to allow die drop of the monkey at any dangerous speed The word "actuated" preferably means bodi initiation and maintenance of actuation during the drop suffϊciendy long to avoid any risk of a had being available to die danger zone

As used herein the term "and/or" means "and" or "or", or both

As used herein the term "(s)" following a noun includes, as might be appropriate, the singular or plural foims of diat noun In diis specification where reference has been made to patent specifications, other external documents, or other sources of information, diis is generally for die purpose of providing a context for discussing the features of the invention. Unless specifically stated otherwise, reference to such external documents is not to be construed as an admission that such documents, or such sources of information, in any jurisdiction, are prior art, or form part of the common general knowledge in the art.

The term "comprising" as used in this specification means "consisting at least in part of When interpieting each statement in dus specification that includes the term "compusing", features othei than that or those prefaced by the term may also be present. Related terms such as "comprise" and "comprises" are to be interpreted in the same manner A preferred form of the present invention will now be described widi reference to die accompany drawings in which

Figure 1 is a view of a post driver of our KINGHITTER™ range showing a vehicle mounted postdriver with a single acting ram for raising the monkey operable by hydraulic valve bank control, and Figure 2 shows an integrated block to provide hydraulic control for the raising/ s lowdrop/ driving drop requirements of the present invention

Figure 3 shows a circuit flow diagram for an embodiment such as shown in Figure 2, and Figures 4A to 4F show in a number of orientations and a number of different view forms (some complete some partial) a preferred arrangement of the interlock valve such as might be used in the circuit flow of Figure 3 and as a slight variation to that shown to the right of Figure 2, Figure 4A showing die arrangement in die same orientation as in Figure 2.

In a preferred form of die present invention a vehicle mounted post driver, typified by any suitable post driver on a tractor with a hydraulic circuit to link to the post driver, is adapted to require a bank of control levers of which preferably two are operable in a couple of modes:

Mode 1 -where no valve of a hydraulic system is actuated, ie, no movement of the monkey.

Mode 2 - where at least one valve is actuated to cause raising of the monkey. Mode 3 - where at least one valve is actuated to allow a slow lowering of the monkey

Mode 4 - where two valves are actuated to allow an increased exhaust flow (whether through one or two controlled valves) to allow a fast drop of the monkey. Many different ways can achieve this outcome whether reliant solely upon hydraulics or other modes of action. Preferably a same lever is required for each of modes 2, 3 and 4 but die or another lever is also required for mode 4

Various hydraulic gallery type systems with valving biases for valves, etc, can be used to ensure a first lever or button can assume the role for one hand and another lever or button can assume the role for another hand of an operator

Such controls would preferably be in a zone (such as shown generally by the arrow 5) Shown in Figure 1 is a post 4 adjacent a vehicle earned postdπving apparatus having a mast 1 up which the monkey 2 can be lifted by cable under the action of a single acting hydraulic ram 6. The monkey as shown in Figure 1 is resting on a post cap 3 on top of the post 4.

A person skilled in the art will appreciate how mode 3 for slowing lowering the monkey 2 to the condition as shown in Figure 1 may lequire die second hand to be free. However, once the alignment has been assured, the ram can be actuated (eg, by one hand or two hands — depends on the hydraulic circuitry) to lift die monkey 2 to the driving drop height.

Thereafter the monkey 2 can be allowed to drop back to the condition as shown in Figure 1 but only when two of the levers of the bank of levers 5 is being held by separate hands of the operator away from the danger zone The danger zone is diat zone between the monkey 2 and the cap 3, or if the cap 3 is carried by a flexible linkage from the monkey 2, between the cap 3 and the post 4 In use however preferably die cap is fitted on the post in advance of die drop

Shown in Figure 2 is an alternative to a two block bank of hydraulic controls. Shown in Figure 2 as 7 is a block having banks of hydraulic control ports Al /Bl to serve any of die hydraulic functions of positioning rams, etc of bases etc of the Fairbrother range of post drivers Examples are to be seen on our web pages mentioned earlier.

Figure 2 shows a tank 8 of or to a port relief cartridge block with a pilot port 9 linked by the bypass hose 10 to a B port 11 of the block 7. An interlock lever (broken lines) operates via poit 12 while a lever (monkey or hammer lever e.g. able to be pulled/pushed) (broken lines) operates via port 13

Shown in Figure 2 as 14 is the Pl , P2 high pressure inlets from a power source (e g the tractor), as 15 an exhaust oil oudet to the power source and an oudet 16 to die monkey lift cylinder

The internal valving of the block 7 controllable by the levers via ports 12 and 13 have die following preferred functionality and with a piloted relief flow (shutde controlled) of about 120LPM.

The pilot port which releases the hammer is connected to tank through two separate pathways' o B port of hammer spool is connected via 10 to tank in neutral o B port of interlock spool is connected to tank in neutral

Operating die hammer section on its own results in following: o Pull lever — hammer lifts as normal o Push lever - hammer lowers at controlled speed, set by flow control orifice in the internalised interlock valve assembly (eg Vz" diameter ports with a 3/8" valve body)

Operating the interlock section on its own produces no result. The oil pushed towaids the pilot port, will flow back to tank through die B port of the hammer section

Operating the two levers together puts pilot pressure into the interlock valve, and pilots the integral relief open. The exhaust oil from the cylinder goes direcdy out of the tank port, combining with the pump flow dirough the monoblock valve. If either lever is released, die pilot pressure from the relief is dropped, and the relief closes to maintain its relief setting. When lowering, the pump piessure is dead-headed into the pilot port of the interlock valve This causes the relief valve to blow momentarily in each drop of the hammer.

Figure 4A to 4F show the manner in which the interlock valve can be formed. Figure 3 shows a preferred circuit diagram of an arrangement typified by apparatus of Figures 2 and 4A to 4F. Shown to the left is the arrangement without a relief valve. Shown to the left of the break (die break to show a region of variability to deal with other hydraulic functions) is the parallel circuit with a single check valve on the inlet port

Shown to the right is the link to the tank and cylinder and with die pilot link shown as a broken line.

In this specification where reference has been made to patent specifications, other external documents, or other sources of information, this is generally for the purpose of providing a context for discussing the features of the invention Unless specifically stated otherwise, reference to such external documents is not to be construed as an admission that such documents, or such sources of information, in any jurisdiction, are pπor art, or form part of die common general knowledge in the art.