A reversible, percussive, ram-boring machine

Abstract

A superior ram-boring machine “mole”, employing compressed air to drive a reciprocating piston onto either forward or rearward anvils thereby imparting momentum. Wherein a control valve received into the rear of the piston interacts with ports therein determining its stroke characteristics. The end receiving impacts, and hence the direction of action are determined by accurately positioning the control valve forwardly or rearwards. Incorporating a robust, air-on, fail-safe “Rapid Reverse” mechanism, actuated by a small rotation of the air hose. Whereby guide means and an indexing collar incorporating or comprising encompassing spring or elastic means having inter-engaging features deforms by flexing and or compression to disengage and is biased to re-engage with corresponding features to position and lock the control valve into forward and reverse settings; thereby assisting easy switching, location and retention of operating positions. The invention also provides improvements in durability, product life, ease of operation and servicing.

1 . A reversible, percussive, ram-boring machine having a cylindrical body, with a reciprocating striker piston therein, powered by compressed air and oscillating pressure differentials to impart momentum onto either a forward or rearward internal anvil; the striker piston stroke being longitudinally displaceable from forward to rearward operating positions by displacement of the relative longitudinal position of a stroke controlling valve means, having a sleeve which engages variably within the length of a bore within the rear of the striker piston, wherein the longitudinal operating position of the controlling valve means is capable of being locked and unlocked by rotation of the air supply hose, with the locking means deforming or creating an elastically stressed state therein to allow the longitudinal operating position of the control valve means to be locked and unlocked by rotation of the air supply hose. 
   
   
       2 . A reversible, percussive, ram-boring machine according to  claim 1  wherein the locking means remains in a stable non use position while the normal operation of the mole occurs and by the deforming or creating of an elastically stressed state moves to an unstable position for the short period the transition occurs to a locked or unlocked position by rotation of the air supply hose. 
   
   
       3 . A reversible, percussive, ram-boring machine according to  claim 1  wherein the locking means is an external means which deforms or creates an elastically stressed state and moves to an unstable position for the short period the transition occurs to a locked or unlocked position by rotation of the air supply hose wherein in use the rotary motion is transmissible until the desired index point(s) are reached and engaged, whereupon the interacting members locate then seat into mating features and the elastically deformed or stressed external means returns to its natural state. 
   
   
       4 . A reversible, percussive, ram-boring machine, having a cylindrical body, with a reciprocating striker piston therein, powered by the complex through-flow of compressed air and the oscillating pressure differentials created around it to impart momentum thereto, which in turn transmits momentum onto either a forward or rearward internal anvil; the live striker piston stroke being longitudinally displaceable from forward to rearward operating positions by displacement of the relative longitudinal position of a stroke controlling valve means, this being a sleeve which engages variably within the length of a bore within the rear of the striker piston, having manipulation means connected thereto and supported by an air supply tube, the same having longitudinal and rotary motion defining guide means, and a air-supply hose attached thereto; wherein the longitudinal operating position of the control valve element is capable of being locked and unlocked longitudinally and circumferentially by manual rotation of the air supply hose, with that rotary motion being transmissible through joining means to the supply tube to drive its features against rotary indexing location spring and locking means to deform and or create an elastically stressed state therein, until the desired index point(s) are reached and engaged, whereupon the interacting members locate then seat into their mating features and the elastically deformed spring means returns to its natural state. 
   
   
       5 . A rain-boring machine according to  claim 4  wherein, the rotary indexing location spring and locking means are provided by a “C” shaped member means resembling a circlip, split ring or collar; having one or more features protruding from its inner profile which engage circumferentially in a bite-like manner to seat into corresponding rotary indexing and locking features on the outer surface of the air supply tube. 
   
   
       6 . A ram-boring machine according to  claim 4  wherein the rotary indexing location spring and locking means are comprised of an annular structure having on its inner profile a captured protruding feature, such as a pin, cam or cylindrical roller bearing or ball bearing that is urged inwards by resilient spring means to engage circumferentially to seat into corresponding rotary indexing and locking features on the outer surface of the air supply tube 
   
   
       7 . A ram-boring machine according to  claim 4  wherein, the longitudinal locking means is provided or assisted by one or more lugs, or followers on the supply tube running within a motion defining arrangement of one or more longitudinal slots and one or more annular grooves in combination, which permits rotation of the supply tube at points longitudinally corresponding with the longitudinal forward and reverse settings, co-operatingly arranged to lock and provide support means against longitudinal loading and shocks. 
   
   
       8 . A ram-boring machine according to  claim 4  wherein, the longitudinal locking means is provided or assisted by an arrangement of guide means, and longitudinal stops acting on the supply tube and one or more annular features which permit rotation of the supply tube at points longitudinally corresponding with the longitudinal forward and reverse settings, co-operatingly arranged to lock and provide support means against longitudinal loading and shocks. 
   
   
       9 . A ram-boring machine according to  claim 4  wherein, when the compressed air supply is sufficiently reduced or switched off, the control valve is longitudinally biased towards its forward operating position, and when the mechanism is unlocked in this state the control valve is urged to traverse to its forward operating position by helical spring or compression means. 
   
   
       10 . A ram-boring machine according to  claim 4  wherein the control valve is longitudinally biased towards its rearward operating position by air pressure means, and when the mechanism is unlocked in this state the control valve is urged to traverse longitudinally rearwards to its reverse operating position thereby. 
   
   
       11 . A ram-boring machine according to  claim 10  wherein the longitudinal force exerted by forward biasing helical or other spring means is exceeded and overcome by such air pressure means, and permits the control valve to traverse rearwards during which the helical spring means acts to provide resistance and therefore damps the motion. 
   
   
       12 . A ram-boring machine according to  claim 4  wherein ingress of potentially damaging soil, sludge, particulates and the like is prevented or reduced during switching of the direction of action of the machine by the through-flow and output therefrom of compressed air. 
   
   
       13 . A ram-boring machine according to  claim 4  wherein the control valve is connected to the air supply tube by a flexible and rotatable ball joint, thereby providing fault and shear loading tolerance, self-centering, optimal path finding and elastic damping means, having therein an internal bore to permit the flow of a compressed air supply there through. 
   
   
       14 . A ram-boring machine according to  claim 4  wherein inter-engaging threads are provided whereby the component cylinders and shafts are screwed together, the same threaded joints having one or more slots or other means in one of their mating threads, thereby permitting insertion therein of malleable, compressible and moderately resilient and elastic insert means during assembly of the joint, thereby providing vibration resistance and tolerance, damping and factional, locking or interference means in cooperation with the mating screw-threaded joints, having been deformed permanently and elastically during the screwing together of the mating parts being joined and fixed thereby, by threads cutting mating threads into the inserts and also compressing them elastically, producing an elastically sprung interference fit between the threads and the deformed inserts, to provide a high frictional co-efficient of a magnitude capable of locking the mating components sufficiently against the vibrations inherent in the ram-boring action of the machine, whilst permitting their intentional disassembly without excessive difficulty. 
   
   
       15 . A method of operating a reversible pneumatic underground percussive ram-boring machine of the type having a reciprocating striker piston within a cylindrical body wherein the striker piston imparts momentum, which determines and drives the direction of action of the machine at the end of its stroke to either the front or the rear internal anvil; and the striker piston stroke is controlled by the longitudinal position of a valve element within the device, wherein the longitudinal position of the valve element is locked and unlocked axially and circumferentially by manual rotation of features on the air supply tube against rotary indexing location and spring means to create an elastically stressed state therein until the desired index points are reached and engaged and whereupon the interacting members seat into mating features and the elastically stressed spring means returns to its natural and relatively unstressed state. 
   
   
       16 . A method according to  claim 15  wherein in operation in forward mode the direction of action of a machine is provided having a piston stroke capable of being switched into reverse mode by rotation of the supply hose through a predetermined arc to unlock the control valve thereby making it free to traverse in the axial plane, whereupon the valve element is capable of being biased by air pressure to traverse axially rearwards into its reverse operating position, thereafter the valve element can be locked in position by further manual turning of the air supply hose and thereby to align and re-seat inter-engaging indexing features of the air supply tube and corresponding rotary indexing location and spring means and providing an air-on reverse mechanism enabling switching from forward to reverse with a live piston stroke. 
   
   
       17 . A method according to  claim 15  wherein from a static state with no active compressed air supply or alternatively with reduced air pressure or reduced air flow the machine can be switched from reverse back into forward mode by manual rotation of the supply hose through a predetermined arc to unlock the control valve thereby making it free to traverse in the axial plane, whereupon the valve element is capable of being biased by helical spring means acting longitudinally to traverse axially forwards into its forward operating position and thereafter the valve element can be locked in position by further manual turning of the air supply hose so as to re-seat inter-engaging indexing features of the air supply tube and corresponding rotary indexing location and spring means. 
   
   
       18 . A method according to  claim 15  wherein the inter-engaging indexing features of the air supply tube comprise rotary indexing location and spring means in the form of an approximately circular flexing spring means, or an encapsulated spring means within an outer housing means or collar capable of providing a gripping or bite like clamping action onto the air supply tube and having smoothly inter-engaging features with mating profiles on their interacting surfaces, such features corresponding with the rotary timing of axial locking means so that manually applied rotary forces are sufficient to disengage the rotary indexing location and spring means and again create an elastically stressed state therein, until the desired index points are reached and whereupon the interacting members seat within mating features and the elastically stressed spring means returns again to its natural and relatively unstressed state locking the mechanism into its alternate operating position. 
   
   
       19 . A method according to  claim 15  wherein the reverse mechanism includes providing an elongated control valve member, which facilitates and controls the flow in the incoming compressed air and having one end with means for connecting to a pneumatic hose for supplying compressed air and manipulating said valve member; a surrounding striker piston and cylindrical outer body and having at the front end a first connector for connection to a percussion impact head and at the other end the aforesaid connection means for connection to a compressed air supply wherein the assembly provides flow paths to facilitate the flow of compressed air therethrough so that the aforesaid connecting air supply tube having at least part of an inter-engaging means for guiding and restricting the movement of said control valve within supporting and guide means to two longitudinally spaced locations with an optional longitudinal compression means or helical spring means to bias the control valve towards a forward position of maximum extension within the body of the mole and an inter-engagement of the rotary indexing location and spring means with the air supply tube; whereby manual turning of the air supply hose through a predetermined arc thereby unlocks the control valve in the axial plane to facilitate longitudinal movement to permit shifting of the stroke of the striker piston therewith to thereby provide means for reversing the direction of the machine's ram-boring action. 
   
   
       20 . A method according to  claim 15  wherein from operation in forward direction, the reverse mechanism is capable of being actuated by manually turning the air supply hose and the flow of compressed air through the machine acts to create a pressure differential which in turn is utilised to drive the control valve's traverse longitudinally rearwards to its rearward setting, corresponding to the reverse mode of operation and this biasing action of the compressed air acting on the control valve is capable of being used to drive the control valve rearwards longitudinally and may be damped by the helical spring or longitudinally acting spring means as it traverses wherein the longitudinal position of the valve member is shifted to provide for reversing the direction of the ram-boring action of the machine therein having a live piston stroke which shifts therewith and without interruption of the compressed air supply therethrough. 
   
   
       21 . A method according to  claim 15  wherein the rotary indexing location and spring means can take the form of a “C” shaped circlip-like indexing, clamping and locking spring means resembling a circlip or collar; having one or more hump-like features protruding inwards from its inner profile and this engages with corresponding mating rotary indexing and locking grooves, recesses flats or similar features along the outer diameter of the air supply tube which runs through the centre along and around the axis of the machine, inside the rear housing assembly and anvil bore. 
   
   
       22 . A method according to  claim 15  the rotary indexing location and spring means is comprised of an annular structure having on its inner profile a captured protruding feature, such as a pin, cam or cylindrical roller bearing or ball bearing that is urged inwards by resilient spring means and this protrusion engages with and seats into corresponding rotary indexing and locking grooves, recesses flats or similar features along the outer circumference of the air supply tube, which runs through the centre along and around the axis of the machine inside the rear housing assembly and anvil bore. 
   
   
       23 . A method according to  claim 15  wherein the hump-like resilient protrusion is located on the outer diameter of the air supply tube which runs through the centre and along the axis of the machine inside the rear housing assembly and anvil bore to engage locking grooves or recesses within the inner diameter of a circumferential element. 
   
   
       24 . A method according to  claim 21 , the rotary indexing and locking grooves or other features correspond with the desired longitudinal and rotary traverses of one or more guide means and wherein the same are comprised of one or more lugs, or followers, which run within one or more motion defining contoured slots or an arrangement of stops or alternate combinations of the features and functionalities thereof, correspondingly and cooperating between the air supply tube and the rear housing assembly and anvil bore. 
   
   
       25 . A method according to  claim 15  wherein the mole is positively locked into its operating positions by the locating and clamping action of the circumferential rotary indexing location and spring means which, or parts of which, are elastically deformed when the air supply tube is rotated against the resilient protrusions thereon or alternatively indentations therein and this deforms within its elastic range to permit the rotation until engaging with the next corresponding features or groove(s) and at this point, the stored kinetic energy in the flexing or compressing action of the circumferential spring or other elastic means acts to drive its hump-like protrusion(s) to seat into the corresponding mating groove(s) or other arrangement of equivalent features. 
   
   
       26 . A method according to  claim 15  wherein the circumferential rotary indexing location and spring means or other deformable elastic means is conveniently located at the rear of the machine within the conical rear housing for easy and quick replacement, either during routine maintenance or to effect emergency repair in the field requiring only removal of the rear conical housing to permit access in order to permit removal and replacement of the same without requiring the reverse mechanism as a whole to be removed from the assembled machine nor for the same to be stripped down, thereby replacement of the circumferential rotary indexing location and spring means can be achieved in a labour saving manner. 
   
   
       27 . A ram-boring machine having a cylindrical body, with a reciprocating striker piston therein, powered by compressed air and oscillating pressure differentials to impart momentum onto either a forward or rearward internal anvil; the striker piston stroke being longitudinally displaceable from forward to rearward operating positions by displacement of the relative longitudinal position of a stroke controlling valve means, and having a sleeve which engages variably within the length of a bore within the rear of the striker piston, wherein the control valve is connected to the air supply tube by a flexible and rotatable ball joint, thereby providing fault and shear loading tolerance, self-centering, optimal path finding and elastic damping means, having therein an internal bore to permit the flow of a compressed air supply therethrough. 
   
   
       28 . A method of assembly of a ram-boring machine wherein inter-engaging threads are provided whereby the component cylinders and shafts are screwed together, the same threaded joints having one or more slots or other means in one of their mating threads, thereby permitting insertion therein of malleable, compressible and moderately resilient and elastic insert means during assembly of the joint, thereby providing vibration resistance and tolerance, damping and frictional, locking or interference means in cooperation with the mating screw-threaded joints, having been deformed permanently and elastically during the screwing together of the mating parts being joined and fixed thereby, by threads cutting mating threads into the inserts and also compressing them elastically, producing an elastically sprung interference fit between the threads and the deformed inserts, to provide a high frictional co-efficient of a magnitude capable of locking the mating components sufficiently against the vibrations inherent in the ram-boring action of the machine, whilst permitting their intentional disassembly without excessive difficulty. 
   
   
       29 . (canceled)