GB2247508A - Converting rotary motion into reciprocating motion and vice versa - Google Patents

Abstract

A device for converting rotary motion into reciprocating motion comprises a Gearbox G pivotably mounted on the axis of Driveshaft D5, suitably upheld by Bearing-means D4 above a Bedplate B, and having two external sprocket driving means G13a and b rotating in opposite directions alternately engaging with a rack C in the form of a roller chain mounted for reciprocating motion upon said Bedplate. Means are provided to pivot the gearbox when the rack reaches the end of its travel thus producing continuous reciprocating motion of the rack. Latching means La, Lb prevent the gearbox from pivoting prior to reaching the end of a stroke, and cam surfaces C7 unlock the gearbox at the end of each stroke and allow it to pivot. The above device may be modified and used to convert reciprocating motion of the rack into a continuous rotary output. In this case the two sprocket wheels are in continuous mesh with the rack and are mounted on their respective shafts through oppositely acting one-way clutches. The device may be used in association with piston-cylinder pumps. <IMAGE>

Description

AN IMPROVED RECIPROCATING MOTION This invention relates to an improved reciprocating motion offering the means of converting the torque of a revolving shaft into:a) a reciprocated motion imparted to a 'crosshead' through any required length of stroke delivered at a constant power / velocity ratio with either an albut immediate change of direction or a delayed return-stroke as required.

b) as in (a) differing however in that the two individual strokes of a reciprocated cycle can vary in their respective power/velocity ratios.

c) where a 'crosshead' as in (a) can, by hydraulic means, operate the 'crosshead' of a secondary unit at a distance from the priming unit which, in turn, acting upon a modification of the aforesaid priming-unit (as in "a") can power a driven shaft through an arc of 340 degrees with the aforesaid constant power/velocity input while a flywheel attached to said driven-shaft completes the cycle through the remaining 20 degrees of arc by its momentum.

d) where the modified version of that defined in t?c?? can be powered by water from a constant head; by steam or compressed air at a maintained pressure by the additional employment of suitable valve-gear motivated by the reciprocating 'crosshead', or again, e) where a modified version of that defined by "c" is operated by two 'crossheads' whereto simultaneous but opposite reciprocation can be applied to a driven part by either manual means or by foot-pedals.

By these seven Embodiments of this Invention and that of the auxiliary equipment pertaining thereto in the fields of Hydraulic and Pneumatic Engineering as detailed in this Specification and Drawings it will be seen that present twofold employment of a crank as a driving or driven medium can be replaced with advantage even though limited to 18 reciprocations per minute.

The original object of this invention was to improve upon the performance of crank-operated piston-pumps when driven by such slowly revolving power-units as undershot water-wheels running at 8 rpm powered by the kinetic energy of streams with velocities as low as 5 kms (3 m) per hour, but as foreseen by the New Zealand Provisional Specification No.219620, (March 13th, 1987), Paye 2, penultimate paragraph, 4th line up; further developments have widened its application.

By such means manw farmers, orchardists and horticulturalists could supplement their existing water supply from an energy source, earlier deemed insignificant, at an economic cost. Such appliances would not require the attention of skilled technicians for either their installation or later servicing being capable of being given attention by any "handyman" as the principles by which they function are clearly visible and selfexplanatory, their design having been simplified with that end in view.

The Embodiments (a), (b) and (c) should not be taken to limit the further employment of this invention to the original purpose for which it was designed, neither that of its counterpart (d).

In the wider field of General Engineering its application could b often employed to advantage.

Further, the term 'crosshead' should be understood to detail that part of the appliance, or of an auxiliary appliance, being reciprocated either directly or by an intermediary linkage. The employment of a connecting-sleeve linking the drive-pins of the twin-opposed pumping-unit to that of the powering means is employed to facilitate the removal of the pumps when servicing of t gland-sealv is necessary.

Of late-years the reciprocated piston-pump has mistakenly fallen out of favour having been replaced by either the centrifugal or screw (augur) type appliances. Admittedly such units possess certain real advantages both to the stockists and apparently to their purchasers. They take up far less roor in the showroo wit their compact design, and when supplied coupled directly to an I.C. engine or to an electric motor have an immediate "eye apl" to the prospective customer.

When the enquirer is then advised that the Efficiency Ratio of these rotary units is in the neighbourhood of 70, while that of the piston-pump is only granted an academic E.R. of 50 , the sale is only too frequently made.

This rating published in innumerable books and papers pertaining to Hydraulics lacks the necessary and informative rider "when actuated by a crank" ... it would be even lower if a cam were employed, lower still if an eccentric.

In direct opposition to that finding it will be found that whe such pumps are provided with a "direct in line" drive Efficiencies within the 90 range can be reached ... no matter how slowly the pump might be operated. This is evidenced by the braking systems almost universally employed in modern transport whether hydraulically or vacuum applied.It will also be found that the piston pump is supreme in the pressurisation of gases as no rotary pump can do more than propel the same at a low velocity; neither can they hold back a head of liquid when in a state of rest while a piston-pump can hold back any pressures and too give any lift: the rotary calls for a definite number of revolutions per minute; the rotary cannot stall its driving means while the piston-pump, if strongly enough built, can even at the slowest of speeds: this is the ultimate head to which, not the pump, but the diving means, can attain.

This 50% ratIng however does give a very good indication of the degree of frictional losses in the employment of a crankoperated piston-pump. The theoretical efficiency of a crank driven appliance must necessarily be in the neighbourhood of 66 if all frictional losses could be excluded.

In one revolution of the crank-shaft the crank-pin travels a peripheral distance of Pi times the diameter of the same yet only imparts to the piston two diametric length strokes. In consequence slightly more than one-third of the available torque per revolution of the driveshaft is lost as far as productive work is concerned.

Since the theoretical efficiency of a crank is a fraction under 648 (not 66% as formerly given) we find, by deducting the 50% given by that academic rating that no less than an approximate 14% is lost through friction in one way or another. The greater part of this is due to the prevalent practice of employing metal to metal bearings to support the crank-shaft, the two bearings of the connecting-rod, for the 'crosshead' and also its sliderails. To this must be included the piston within the cylinder bore. To these factors must also be added, only too often overlooked, that gland-packing can exert too great a pressure upon the piston-rod: the means proposed by this Specification will reduce such losses considerably.

Further frictional losses, due principally to design found within the puml itself; the valves, valve-ports and passage-ways can be too r:-:'trictive; the valves are too often at right angles to the bore while ideally they should be in line with the same, while frequently the delivery line is of too small a diameter.

This is a common fault due to two mistaken ideas. The first is to save money which, in time, it does not; the second is the common belief that a larger diameter pipe than the outlet of the pump would increase the back-pressure upon the exhaust valve o the pump making it more difficult to lift. This is not so as the back pressure upon the valve is due to the area of the same and the height of final discharge. The volume of water upheld is of no consequence.

A larger diameter delivery-line reduces the initial velocity of the discharged water from the pump and in turn the water rises within the delivery at a lower velocity with attendant lower frictional losses.

Of all frictional losses detailed above the largest single factor is shared between the conventional 'crosshead' and its corrective slide-rails. This could readily be reduced by the employment of a longer connecting-rod whereby the recurring angles of pressure upon the slides could be proportionally lowered. This however would call for a longer bedplate for the unit adding not only to the weight but also to the cost.

Since the Object of this invention was to deliver a constant power at a constant velocity throughout a stroke of any desired length for the primary purpose of pumping water all the peculiar factors relative to the design of normal piston-pumps have been studied with an eye to improving upon their performance. In consequence d pump, akin to an hydraulic-ram, possessing minimal friction-factors will be presented in this Specification together with Drawings pertaining to the same.

It is frankly admitted that while a crank can operate at any desired number of r.p.m's (with the attendant losses of effort previously enumerated) the means of reciprocation herein disclosed is limited to 18 - 20 per minute. However, when the driving-means exceeds this speed it can be geared down with a resultant increase of delivered power.

Another object of the invention is to offer a trouble free appliance of simple contructio and assembly whereby the handyman would be able to service the same owing to its simplicity of design ensuring thereby it could be offered at an attractive price both to the home and overseas markets.

Modern technology now provides Aluminium alloys and bright steel extrusions in a variety of cross-sections all accurate to two places of decimals in mm's. The use of such materials ensures a great reduction in the need of machining as such tolerances are quite acceptable without further attention. Likewise available are P.V.C. sheet and tubing, now readily weldable an capable of being machined to fine limitsnand tooçflat plate in a variety of thicknesses ideal for the barrels, gland and valve boxes of the pump assemblies.Roller-chain and a wide variety of rollerchain sprocket blanks, dog-clutcEles and ratchet-wheels together with Linear Bearings (having a steel track to extremely fine limits of finish) are now stocked by almost every Transmis-ion Equipment dealer while the necessary "U" seals can be obtained in all size from Hydraulic Engineer suppliers.

A great aid in the assembly of various parts are the propriety metal and plastic adhesives which, because of the "slip" they provide before drying-off, give time for an accurate lining-up to be made. If the part to be positioned may need a more secure fastening it may be pre-drilled then adhered into position after which that part to which it is to be secured may also be drilled and a permanent holding by suitable means effected ... a great deal of time may be saved by such means.

Specific Embodiments of the new invention will now be described by way of examples of its reciprocal employments with reference to the accompanying drawings which due to the apparent complexity of the mechanism to be described the descriptive text that follows will treat the complete unit as eighteen (18) separate self-contained units giving to each assembly a coded prefix letter together with its appropriate number, each number in sequence, for ease of discernment. A separate Copy will be enclosed to be attached to the Drawings for the aid of the Examiner.

The Code letters being: B Bedplate or chassis D Driveshaft - in one Embodiment this is an input shaft; in the case of Drawing 12, a driven shaft.

G Power Transfer - GEARBOX C 'Crosshead', or rack L Loch.ing means 1 & 2W Counter-balance-weights S Spindles P ............... Pump Assembly (conventional valves not shown) G Glands for same H Hydraulic or Pneumatic Engine R R.;ms Pt Piston PG Pump-Gla-nC' PF Pump Flange Pm Pump Barrel DS L)L ive Sleeve TF Terminal Flange V Valves As to the Drawings; the scales vary from one-third, one-half and full size; this should not be taken to limit the size of the Appliance but to present each assembly as large as possible on the permitted size of sheet.

Other objects and advantages of the present invention will become apparent from the following detailed description and visually clarified by the 13 accompanying Sheets which form part of this Specification. Each sheet will be dealt with in sequence.

Sheet 1 (Page 12-15 inclusive) (Scale one-third) Figure 1 is a perspective view of the preferred Embodiment with particular reference to the Bedplate Assembly.

Sheet 2 (Page 16-19 inclusive) (full size) Figure 2 is a partially sectionalised view of main driveshaft bearing assembly with pivotable end flange.

Sheet 3 (Page 20-22 inclusive) Figure 4; a schematic presentation of the internal sprocket-chain drive and balance-weight within the Gearbox.

Figure 5; a schematic presentation of the front face of Gearbox, exterior sprocket drive wheels, Locking Means and Counter-balance-weight.

Sheet 4 (Page 23-28 inclusive) Detail of internal gears and axles, spindles and rollers and internal balance weight.

Sheet 5 (Page 29-35 inclusive) Detailing 'Crosshead'.

Sheet 6 (Page 36-40 inclusive) Means of inclining Gearbox through any desired length of stroke.

Sheet 7 (Page 41-43 inclusive) Ditto for shorter length strokes.

Sheet 8 (Page 44-46 inclusive) Means of Locking Gearbox throughout length of stroke.

Sheet 9 (Page 47-48 inclusive) Figure 2; means of obtaining a stroke at one power/velocity with a return at a differing Power/Velocity Ratio.

Sheet 10 (Page 49-5?. inclusive) Detailing Pump-'crosshead , mounting of same and cover unit.

Sheet 11 (Page 53-57 inclusive) Detail of pump-glands and alignment of cylinders; detailing Glands & Valve assernb y.

Sheet 12 (Page 58-61 inclusive) Side elevation of Hydraulic/Pneumatic Engine detail closed-circuit drive.

Sheet 13 (Page 62-3 inclusive) Detail of water discharge from Hydraulic Engine.

DESCRIPTION OF THE INVENTION SHEET 1 A suitably upheld bearing means D4 supports a Gearbox G which is pivotable upon the axis of its driveshaft D5 which by an internal arrangement of sprockets and roller chain revolves two external Drive-sprockets at a lower level in opposite directions. These same Drive-sprockets G13a and b are alternatively brought into meshing contact with a roller chain, acting as a rack secured to a 'Crosshead' C running horizontally and parallel to table outer face of the said Gearbox. The 'Crosshead' is positioned beneath the two Drive-sprockets sufficiently low enough that when the Gearbox is in a state of balanced equilibrium both the aforesaid Drive-sprockets are just clear of engaging with the rollers of the rack.

The repetitive engagements of the two Driving-sprockets is effected tfit inclination of the Gearbox hy the Counterbalance-weight 1W which is moved from one side to the other of its guide-rail on top of the Gearbox by the reciprocated motion being imparted to the 'Crosshead' to which it is linked by the methods shown. During its traverse from right to left the right-hand Locking Means (La) is maintaining the right-hand Driving-sprocket in the drive position. As the rolling weight approaches the end of its traverse a cam C7 (the counterpart of C7a) upon the right-hand end of the 'Crosshead' is approaching the roller on the lower bell-cranked arm of the Locking Means (not visible, as hidden by same).The two are so synchronised that the cam, lifting th lower arm of the Locking Means unlocks the right-hand side of the Gearbox which is promptly tilted to the left by the Counter-balance-weight which is now on that side of the Gearbox and is immediately locked in that position by the left-hand Locking-arm whereupon the return of the 'Crosshead' is effected as now the left-hand Driving-sprocket has taken over.

As best shown on Sheet 7 Figure 1, a power-take-off Pin 1W-4 is shown protruding outwardly from the column rising from the Crosshead' and controlling the motivation of the Counterbalance-weight while the counterpart of the cam which has acted upon the right hand Locking Arm can be seen at the extreme left end of the 'Crosshead' in the form of an inclined plane. This same principle but by differing means is shown on Sheet 6.

Reference Sheet 1; no pumps are shown on this Sheet but the two mounting brackets, one at each end of the foremost Bedplate member, are. These if so required can be supplemented Ly a third, not shown, in the centre.

Neither are shown two vertical pillars behind the Gearbox upon which inward extensions of the two Locking Spindles come to rest at the extremes of the "rocking" action of the Power-transfer Gearbox. Each pillar is capped with a rubber cushion which not only minimises noise but more importantly prevents undue pressure upon the rollers of the chain-rack thus preventing frictional losses. These are indicated on Sheet 9 by broken line means.

In the above Description minimal part numbers have been given other than those that relate to the Bedplate B, the Driveshaft D5 and the Bearing Assembly D4. All component parts will be detailed in this Specification and thus identified upon the Drawings.

Sheet 1 THE BEDPLATE (one-third scale) As shown this is substantially rectangular in Plan and is a simple and inexpensive assembly requiring no other machining than the drilling of clearance holes for either pop-rivets or other acceptable means of securing the Bearing Assembly (detailed on Sheet 2): the pump-mounting brackets as mentioned above and the positioning of the linear-bearings for the 'crosshead'. The front and the two sides, B1, Bla and Bib respectively, are of Zed-section extrusion, the lower and outer flange of which can be used in securing the same on a permanent site the flange being drilled as necessary.

A decking B3, of a gauge capable of carrying the estimated loading, is adhered to the front and sides by metallic adhesive reinforced by additional means as may be deemed necessary, on the left of the longitudinal centre-line, of a sufficient width to give adequate supportive means to the linear-bearings which support and form part of the 'Crosshead Assembly' being thus secured after the Gearbox is mounted and too for Locking Arm Brackets.

The siting of the Bearing-support D4 and its distancing from the positioning of the 'Crosshead' upon the decking already dealt with is determined by the width of the Gearbox together with that of the Bearing Means D4 and also the fixation of the exterior Drive-sprockets upon the two side elevations. Drawings No 9 & 12 both show this necessary common factor applied in differing circumstances.

Sheet 2 details the construction and purpose of the DRIVE INPUT SHAFT D5 and its relationship with the pivotal means of supporting the Gearbox on the axis of the said shaft by a partially sectionalised side view of the Bearing Housing D4 (Figure 2) and an end elevation of the same by Figure 3, both full scale, while by Figure 2a the detailing of the journalising of Driveshaft D5 is depicted, the power input being taken on the right-hand side of the same.

The body of the upheld Bearing-means D4 is ideally formed fro a black iron water or steam socket of the appropriate diameter (preferably black for ease of later welding) which, while not shown on the Drawing, is threaded throughout its entire length.

Use is made of a portion of this threading as shown on Figure 2 and too of an already threaded blanker D6.

This latter is machined to conform to the drawing becoming the race-carrying flange D6 and the race D6a is pressed into position upon the centre-line of the same. The opposing end of the body D4 is machined to uphold a substantial ball or roller race-bearing D6b into the bore thus being in axial alignment with bearing D6a.

As best shown by Figure 3 a flange with an outer flat face, namely D7, has, on the reverse, as seen on Figure 2, an inwardly protruding ring to accommodate the pressed in bearing D6c..The centre of this said flange D7 is bored to give the barest of clearances to the terminising journal of the shaft D5 (Figure 2a above). Likewise the circumference of the said flange is machined to the barest of clearance to the machined bore of the bearing support D4 into which D6b will be pressed later while the outer surface of the aforesaid ring is machined for insertion into Bearing D6b.

The Flange D7 is also drilled and tapped as shown by D7a, b and c all on a common pitch-circle and equidistant one from the other. Into these tapped bores, studs, as shown by Figure D12, are screwed, by which, the Power-transfer Gearbox will be attached to the pivotable flange.

A plan of the Bearing-Bedplate D8 is shown (half-size) on Sheet 9, Figure 4, while the two support cradles, welded as seen to the Bedplate, are both identical one of which is best shown on Sheet 2, Figure 3. The Bedplate after being marked out and drilled is first used as a template to mark out its bolting and securing position on the two opposing right-angled longitudinal members B4 and 4a sown on Sheet 1. It is therefore positioned there at the mid-centre of the two horizontal flanges and at right angles to the parallel front member B1. Prior to the Bedplate being welded to the Body of D4 the means of lubricating the internal bearings calls for the attachment of the necessary means of both filling and draining the same D9 and 9a. D9, the filler, also determines the level of oil in the sump, and no greater depth of oil than one-third the radius of the said body is required.

The Body of the Bearing Housing D4 is now welded to the two support cradles rising from the Bedplate. The heating of the same during this process expands the tubular Housing and simplifies the pressing home of the large bearing D6b.

D6b should be a sealed unit and grease-lubricated for life and both seals are retained. In consequence no oil can get pass the sealing means while none can pass through the press-fit between the bearing and the Bearing-housing D4.

The bearing D6c is now pressed into the Flange D7, as shown in Figure 2, to carry the left-hand narrower extension of the Driveshaft D5 (Figure 2a) while bearing D6a is pressed into the opposing threaded flange D6.

The Driveshaft D5 (Figure 2a, Sheet 2) is machined to ensure a tight press-fit in the right hand bearing D6a but with only a moderate pressure fit into the opposing bearing D6c. Before it is fitted, however, two holes need to be drilled into the shaft, as shown, to take two pressed-in wire uprights to the extremities of which are attached felt swabs D11 and 11a which, with each revolution of the driveshaft, will be immersed in the oil within the sump and when each reaches the top vertical stance the oil will run down on to the shaft in close proximity to the bearings D6a and c lubricating the same.

The threaded end flange D6 allows not only an adjustment to the pressure on bearing D6c to be controlled to a free running stance but also ensures that no undue pressure is exerted on the same as it is apparent that the lower bearing means is not backed by flange D7.

It should be noted that bearings D6a and b are shielded only on the outwardly facing sides by oil-retaining means but are open to lubrication on their inner faces. The said Bearing Means is mounted between two longitudinal angular sections B4 and B4a as shown on Sheet 1.

SHEET 3 As best shown on half-scale Sheet 3, Figure 4 the Power Transmission Gearbox is presented schematically showing the internal arrangement of roller-chain linked sprocket-wheels Gl2a, b, c and d, being driven by the upper central G12 mounted upon the Driveshaft D5 while the back-plate of the Gearbox is attached to the pivotable flange D7, as shown on Sheet 2, Figure 3, by studs D7a, b and c. The sprocket G12 drives the three sprockets G12a, c and d in the same rotationary direction as itself since all are inside the loop of chain whereas sprocket 12b, driven outside the loop, is revolved in the opposite direction.The driven sprockets G12b and d are securely attached to their respective Driveshafts which extend outwardly of the forward face of the Gearbox C11a being upheld by frictionreducing bearings pressed into the rear and frontal walls of the same, supporting thereby, the external Drive-sprockets Gl3a and b, as shown by Figure 5.

The easy running of this means of drive is further enhanced by the roller-chain being given an extra link in length than theoretically called for.

Since the Gearbox is pivotable it is possible by tilting it first in one direction and then in the other to employ the contrary rotations of the two Drive-sprockets Gl3a and b to impart a reciprocated motion to a suitably supported 'crosshead' C1 provided an efficient rack is employed. Roller chain, secured at its extremities, and engaging with sprockets has proved a more flexible means of drive than the conventional gear and machined rack which, by their very nature were too selective, apart from the expense factor.

A rack employing roller-chain and upheld and positioned by linear-bearings is albut frictionless and is employed in all the Embodiments of this invention.

As shown on both Figures 4 and 5 the linear bearings C2 and C3 are positioned with their centres directly beneath the perpendicular of the two Driving-sprockets, G13a and b being secured, along the line of drive, to the platform B3 as best seen on Drawing 1 being the foremost decking member of the Bedplate. The 'crosshead', with its roller-chain rack (to be described later) is elevated in height above the Bedplate so that when the Gearbox is in a state of balance there is a minimal clearance between the tip of the teeth of the Sprocketdrivers G13a and b and the top of the rollers of the rack-chain.

This clearance and the effect of tilting the Gearbox so that a driving-sprocket might engage with the rack is shown on Figure 4. G12b is seen with two perpendicular lines linked by one at right angles to both and using the centre of the driven-shaft an arc is struck with its axis on the pivotal Driveshaft D5.. It will be seen that one pitch-length is lost at the commencement of each stroke. It follows then that the distance between the centres of the two Drivers Gl3a and b, on Figure 5, must be in multiples of linkage-pitch. It must also be borne in mind that one revolution of each driver cannot impart a drive equal in length to the circumference of its pitch-circle.However the employment of 18 toothed Drivers can impart a consistent power velocity drive through 340 degrees while the change over of the driving-means is effected during the remaining 20 degrees of arc... the loss of the drive of one tooth.

Sheet 4 (full size) As shown by Figure 7 the two walls of the Gearbox are ideally of sufficient thickness to equate the width of the bearings employed. If however the resultant weight should be deemed excessive then lighter gauge walls may be used to which reinforcement discs may be adhered to the side-plates to increase the width; the said discs being concentric with the required bearing-bores of the two lower drivesafts G12b and d.

Figures 6,7,8, and 9 show details of the internal gears employed together with the necessary shafts, bearings and necessary bushings while Figures 11 and 12 show both by Plan and Elevation details of an internal Balancing-weight G14. Also shown are one of the two identical Locking Spindles LSa and b (Figure 8) and too the means whereby the roller as in Figure 10 is retained upon the right hand protuberance of the Spindle by means of a washer and retaining screw. The roller is either of nylon or again can be of case-hardened steel providing a high state of polish both on its external surface and within its bore can be obtained; they must run freely upon the spindles.Not shown is a further Spindle, indicated on Sheet 3, Figure 4 and nominated as Gl2c which has no forward protuberance beyond its collar nor, rearwardly, beyond the common length of thread, all three spindles have threaded terminations as too the respective bores on rear-plate of Gearbox.

This latter upholds the lower central jockey-sprocket; Lsa supports jockey-sprocket G12a as shown on Figure 8 while Lsb supports the interior balance-weight G14.

As will be seen from Figure 6 sprocket-blanks which are readily available having protruding lugs within the annulus originally to engage with a splined shaft. These can be pressed onto a shouldered bush and be secured thereto by filling the resultant gaps with weld; electric welding means should be employed as the excessive heat of gas could well reduce the temper of the steelblank and that of the hardened teeth leading to excessive wear.

In this Embodiment the main imput driver G12, the two lower intermediate drivers C12b and d and too the exterior drivers Gl3a and b all conform to this manner of construction whilst all are mounted to their respective shafts by a plurality of grubscrews, the shafts being pipped (indented) at the point of contact. Such means ensure no slip can possibly occur and prevents any possibility of the shafts being scoured in consequence.

As shown on Figure 7 the mounting bush acts as a distance piece between the two opposing bearings making contact only with the inner ring of the ball, or roller, race. Once again it is pointed out that while the bearings are sealed externally they are open internally to ensure constant lubrication is provided by the oil carried and dispensed by the oil-carrying chain.

Shown by Figure 8a adjoining Figure 8 are the spacer-bushes required on the two Spindles Lsa and b while Gl2c (the central and lower spindle) has an internal bore equal in diameter to that of the Spindle while externally a bare fraction over that of the outside diameter of the inner race-ring. Their widths vary inwardly from the two opposing inner walls of the Gearbox with the intent that the teeth of the sprocket are upheld central to the two aforesaid opposing inner walls. In consequence the Spindles act not only as supportive means to the two jockey sprockets but supply ancillary means to support the two opposing walls of the Gearbox in parallel alignment: the forward extensions thereon acting as Latching-means.

To facilitate the assembly and later possible dismantling of the Gearbox it is advisable to so journalise the two driveshafts supporting the internal drivers G12b and d (as shown on Sheet 3, Figure 5) that a tight press-fitting is needed to insert them into their respective bearings fitted to the back-plate of the Gearbox Glib while a lighter pressure is required to insert them in and through the opposing bearing on the front-plate Glla beyond which it can be further reduced in diameter for the necessary remaining length. As best shown on Sheet 9 two differing lengths of exterior Driveshafts are shown on Figure 1 while on Figure 2 the difference is further exaggerated.

To assemble the Gearbox the aforesaid shafts G13a and b are pressed as above stated into their respective bearings in the back-plate Gllb. The pivotable flange D7 of the Bearing-support D4, as shown on Sheet 2, Figure 2, is smeared with metallic adhesive; the back-plate of the Gearbox is rendered up to the three projecting studs upon the same and secured thereto by nuts (the said rear-plate of the Gearbox having a clearing bore through which the Driveshaft D5 can enter into the box stopping just short of the inside of the front wall of the box).The interior Drive-sprocket G12 conforms to a similar mounting-bush as shown by Figure 7 which however is narrower in width since it must run freely without contact with either of the two interior side walls of the Gearbox, it is secured to the pipped shaft by a plurality of grub screws whilst it was only possible in a sectionalised drawing to show one.

The two lower internal driving means G12b and d are slid upon their respective shafts and secured thereto. The front-plate Glla can now be rendered up to the said shafts and gently tapped to effect a partial entry upon the same. By the judicious use of a clamp the two sides can be brought together while the insertion of the two spindles LSa and b, together with the bushmounted jockey sprockets, with their threaded ends can effectively bring the two sides of the box together with the further employment of Spindle G12c.

Spindle LSb is now unthreaded and reinserted together with the interior balance-weight G14 which in view of the fact that its final inclination may be such that the single securing means might be out of reach may call for at least a further two such threaded bores each fitted with a grub screw and not the one only shown on Figure 11, Sheet 4.

The overall length of the two lower driveshafts projecting from the Gearbox is determined by the positioning of the Crosshead to be later described.

The drive-chain is now fitted around the sprockets as shown by Figure 4, Sheet 3 ensuring that an extra link is allowed over that which is apparently necessary; it has been found that by this means frictional losses are reduced to a minimum.

If the frontal platform of the Bedplate is removed it will be possible to pivot the Gearbox not only to seal the same by means of adhesive backed aluminium strip, the said adhesive being impervious to mineral oils, but also to cover the strip with the prepared bottom and side plates which are secured as aforesaid by a plurality of screws.

The Gearbox car now be balanced by means of the internal balance weight. It should be borne in mind that while the Gearbox itself has been brought to a state of balance the protruding drive-axles and their attendant exterior driving sprockets may not be identical in weight wherefore rebalancing by external means must be employed. In which case a supplementary balance weight may be adhered or otherwise attached to the respective ide-wal to obt in an accurate state of balance.

As best shown on Sheet 9 two differing lengths of exterior Driveshaft are shown on Figure 1 while on Figure 2 the difference is further exaggerated.

All that is needed to finish the Gearbox is the fitting of the oil-filler cum drainer G15. This, ideally is a 10mum (3/8") brass flanged elbow screwed into a brass lock-nut sweated to a pre-drilled cover-plate on the selected side; the aforesaid sealing strip being pierced. A suitable sealing washer should be used between the flange and the nut. Only a low level of oil is required, sufficient to cover the chain running just above the bottom of the Gearbox. Running continuously through the oil sufficient quantities are carried by the said chain to the gears reaching the axles and the interior unsealed side of the bearings.

The running rail and the roller running on the top of the Gearbox, whilst necessary to control the alternate inclinations of the same and although connected thereto, are not considered to be a part of the Gearbox.

SHEET 5. 'The Crosshead Cl' or 'Rack'.

(Refer Sheets 1 & 3; Figs. 5,6 & 7) The three Figures 13a,b and c, presented on this Sheet set out the basic design of the 'Crosshead' which, while it may not always retain the angular cross-section shown will still retain the same basic principles of operation.

The 'crosshead' is the means whereby, a) the torque of a driven shaft is converted into a reciprocated linear means of power.

b) its control of the dual means employed to provide the motion by the locking-in and the unlocking of the rotary driving means at the commencement and termination of each imparted linear motion ensuring thereby a positive drive at a constant power/velocity ratio, and too the control of the length of imparted stroke.

c) as seen on Sheet 9 where the power/velocity ratio can differ, te one from the other, through the two mutivations contained in one reciprocated stroke, when delaying means may be introduced to prevent immediate locking while buffering means could be employed to arrest any momentum and overcoming the inertia supply an initial return movement prior to its re-engagement of drive.

d) The term 'Crosshead' need not necessarily be limited to one that is supported by the same Bedplate as that which upholds the pivotal Gear-box G as shown by Figure 1; it can form part of any separated appliance needing reciprocation e.g. a rail controlled movable table running parallel to the outward face of the Gearbox. In such a case the only direct connections with the Gearbox would be the alternate engagement of the Drive-sprockets with the table-supported-rack, the Cams adjacent thereto and the means, to be detailed later, whereby the Gearbox is inclined in the opposite direction for the reversal of the preceding imparted motion, which inclination may be delayed by supportive means not shown being attached thereon as in C above.

Whilst the mechanical means, subsequently described, are simple mechanisms to maintain, in either of its two forms, it might well be necessary, in certain cases, to employ hydraulic rams beneath the Gearbox to incline the Gearbox in both directions.

However such means are only recommended in the case where any failure of the system is immediately recognised and where service is readily available. In normal cases when used by a farmer or an agriculturalist or orchardist the mechanical means presented herein are considered advisable as any failure is not only readily discerned but is simply rectified by the replacement of a worn part.

It will be noticed that the 'Crosshead' carries a Central Cam and a Cam, facing inwards, at the termination of the two ends of the same. The Central Cam is operative only when the inputdrive is of a clockwise rotation, as seen from the 'Crosshead'; those at the extremities of the same call for an anti-clockwise rotation of the Driveshaft.

The 'Crosshead' is not rigidly attached to the Bedplate B.

It is upheld off the same by two Linear Bearings as shown on Sheet 3, Figure 5 as C2 and C3 so positioned that the Linear Centres of each are directly under the running-centres of the two Drive-sprockets when each are in the inclined position as indicated on Sheet 3, Figure 4. The overall elevation of the 'Crosshead' racks C5 and C6 above the Bedplate is primarily determined by the radius of the Pitch-circle of the Driving sprockets G13a and b, the gauge of the metal used for the 'Crosshead-bed' the overall height of the Linear Bearings and half the height of the roller chain-rack employed.

The overall length of the 'Crosshead' is naturally determined by the required length of stroke. This is best converted into the number of links needed for that length of motivation to which must also be added another four links for anchoring means plus one further link for the change over; this number must be doubled however since that is the movement in only one direction. The anchoring of the chain-racks is best achieved by vertical and horizontal sheer-pins. At the outer extremities of each chain vertical pins are employed penetrating first a coverplate through the chain-link and into the thickness of the 'Crosshead' itself. The Cams C7 and 7a are likewise secured in a similar manner and again by the means of countersunk screws through the aforesaid cover-plate of the cam and into the threaded bores in the bottom of the 'Crosshead'.

The central Cam C4 is ideally secured to the bottom of the 'Crosshead' by countersunk headed screws while the two chains, one each side of the same are anchored by common shearpins which pass through the chain links, after the removal of the original rivets, and through the cam as best seen in Figure 13.

Figure 13c shows in frontal elevation and partial side elevation of but one of the many variations of 'Crosshead' that can be employed.

The employment of twin chains C5 and 6 is strongly advocated as shorter lengths are easier to replace than a single long chain.

Sprocket-wheel teeth are pointed and hence far more selective than cut gears which will not readily engage with a machined rack. However these pointed Sprocket teeth protrude through the normal depth of chain failing in consequence to fully engage with the rollers of the chain and tending to ride upon the upper surface of the floor of the 'Crosshead'. This can be overcome by one of two ways; a) by milling a groove central to the centre-line of each of the two chain-racks to the required depth and slightly wider in width than the thickness of the sprocket or b) by the adhering of metal strips of appropriate gauge to the surface of the 'crosshead' under each of the two sides of the chain separated by a width sufficient to clear the teeth of the driving sprockets.

It is imperative that the 'Crosshead' is mounted and maintained parallel to the face of the Gearbox and the employment of metallic adhesive simplifies the attainment of this requirement.

The rail of the linear bearing is first adhered to the bottom of the 'Crosshead' using either one of the two edges as an accurate guide to its alignment. When the bond is effected the two Bearings are run on to the rail and their respective seating areas smeared with a coating of metallic adhesive. The 'Crosshead', with the two mounted bearings is now positioned upon the baseplate beneath the two external Sprocket-drivers positioning the bearings directly beneath their axles and with the slip provided by the adhesive, prior to its setting off, by tilting the gear-box first one Driving-Sprocket is engaged with its chain and then the other. Since some slight movement may have occurred this can be repeated until a satisfactory alignment has been established. This should and can be accomplished prior to the adhesive effecting a bond.However if the first attempt is unsuccessful a slight tap will part the bond and after the surfaces have been scraped clean the process can be repeated. The bond is allowed to set whereupon the baseplate ca; be removed from the Bedplate and permanent securing mean employed after having drilled through the same using as a guide the bores provided by the manufacturers of the bearings. This would entail running off the 'crosshead' from the Linear-bearings and replacing the same after securing the bearings and securing the running-rail to the 'crosshead' by permanent means.

As to the supportive means offered the 'Crosshead' by the use of Linear Bearings it is considered essential that the bodies of the same be positioned, as earlier advised, directly under the driving-sprockets the action of which is two-fold. While imparting a horizontal motivation to the 'Crosshead' there is the question of downward thrust to be considered and this is best countered by the constant resistance of the Bearings. In consequence the rail under the 'Crosshead' has its flanges pointing downwardly. This has the advantage that no dust can settle upon the rails. Since there are a variety of Linear Bearings now available each presents by their design, a differing approach to the adequate means of providing lubrication to the rail.In many cases the grease nipple provided will be inaccessible wherefore they would need to be removed and replaced with a suitably formed length of pipe to which the said nipple can be threaded forward of the 'crosshead' in a suitable position for servicing.

The lubrication and protection of the 'Crosshead' against dust and other contamination by air-borne means is not shown upon the Drawings. This can be effected by the following means. Sheet 5, 13c together with other portrayals, show the angular section of the 'Crosshead'. As seen on Sheet 9, Figures 1 and 2 both, showing the same in cross-section, also include a rear walling on the inward side of the 'Crosshead'. Already the 'Crosshead' is blanked at both ends by the two opposing Cams C7 and 7a and by this means an oil-bath can be formed. To protect the lubricant a removable cover-plate is fixed to the 'Crosshead'carrying-platform by suitable means.The said cover-plate is provided with slots whereby the two arcs of the Drivingsprockets can obtain access to their respective racks while other similar slots are also provided through which the lower and opposing lower arms of the two Locking Arms La and Lb, as best shown on Sheet 3, Figure 5, can rise and fall when operated by the Cams upon the 'Crosshead', while to cover the two Driving-means a light cover-unit attached to the 'Crosshead' cover-unit by releasable means rising to above the level of said Driving-means at their highest point of lift and by flanged means covering the same and enclosing the said two wheels by said flanges in close proximity to the forward face of the Gearbox.

SHEET 6 Counter-balance-weSqht Assembly 2 fM2W In common with 'Crosshead C1' the 'Crosshead' employed in this Embodiment is angular in cross-section and use is made of the same not only to actuate the two types of Counter-balanceweights employed as mechanical means of tilting the Gearbox at the end of each stroke but also to mount a convenient powertake-off drive-pin: both call for such a cross-section.

It was earlier stated that any desired length of stroke could be met by this reciprocated system and this is achieved by the following means, namely, that a drive can be sustained as long as one Driving-means is held, and locked in mesh wit its particular rack upon the 'Crosshead'. It follows therefore that the Counter-balance-weight must first give the Gearbox the tendency to drop and engage the other Driver to its particular rack prior to the end of the preceding stroke and hold the Counter-balance-weight in its position until the preceding stroke is terminated. Ideally this should take only a fraction of the 'Crosshead's' motion prior to and just after the middle of the length of imparted stroke.

Counter-balance-weight 2W is used for this purpose only when the length of required stroke exceeds the width of the Gearbox, or the overall length of the 'Crosshead' is too long to be supported by a Bedplate common to itself and the Gearbox. In such a case it is apparent that the Power-take-off Pin 2W-4 must necessarily be maintained on the original plane by means beyond the aforesaid Bedplate.

With reference to Sheet 6, this assembly, consisting of an upper and lower arm pivoted upon the axis of the Driveshaft D5 is sow by Figure 1, a side elevation, and by Figure 2, a frontal presentation of the same.

By the following means only a fraction of the imparted stroke is required to move the Counter-balance-weight from one side of the Gearbox to the other and this is achieved in a relatively short distance of 'Crosshead' traverse just before, during and after the mid-stroke position of each consecutive stroke.

As can be seen when comparing Figures 1 and 2 the upper portion of the offset lever nW-3a encloses the Counter-balance-weight 2W1 on both sides having a spanning upper section that connects the two parallel sides of the said lever-arm, the span being of sufficient width for the frontal portion to just clear the front face of the Gearbox G, while rearwardly clearing the back of the running-rail 2W8, the said running-rail being secured at the top of the Gearb.

The two opposing sides of this enclosing means are slotted for the running movement of the axle of the Balance-weight 2W6 as it is moved from the central stance shown to either the left or right terminating, as shown by Figure 2, in a position near an end of the aforesaid Guide Rail. The Balance-weight is controlled by the Spindle 2W-6 the diameter of which matches that of the bore of rolling Weight 2W-1 while the slots have a running clearance for the same; rearwardly this Spindle has a flange while forwardly a washer, overlapping the slot, is secured by a split-pin.

The upper and the lower sections of this offset lever are axially spaced apart by a flanged bush 2W-2 the upper portion being attached thereto by a weld while the lower portion 2W-3b is attached by a plurality of dome-headed screws to afford a simple method of dismantling if required. The pivot 2W-1 upon which the two levers are upheld is secured to the Gearbox on its outer face by both a dowel, which enters a prepared bore axially in line with the Driveshaft D5 re-inforced by a flange adhered to the same outer face by metallic adhesive. The lower arm falls in close proximity to the inner side of the upright wall of the 'Crosshead' CI while at a point near its two extremities (refer Figure 2.) the distance between the front of the lever and the centre of the 'Crosshead's' upright wall is spanned by two mini-bearings 2W-9a and b supported on flanged running spigots 2W-lOa and b.As will be seen later the top of the 'Crosshead's' upright wall will serve as a running rail with the exception of a cut-away portion shown by Figure 2.

With further reference to Figure 2;- as shown, the lower portion of the lever 3b is shaped as a splayed fork with a determined length and width of aperture between the prongs - a clearing width to allow slight freedom at the top and sides to an activating roller 2W-5. Both the extremities of the prongs are profiled with one intent whereby the roller 2W-5, shown at the top of the bifurcation of the prongs will, when moved horizontally in either direction, commence to lift and support the lower lever whereby one of the two lower rollers, defined earlier as 2W-9a or b, as shown on Figure 1, has its lower edge raised to the height of the upright wall of the 'Crosshead Cl'.

Since 2W-S, as will be explained in due course is an integral part of the 'Crosshead Cl', it consequently swings the lower portion of the lever in its direction of traverse moving the Counter-Balance-Weight 2W-1 towards the opposite side of the Gearbox. In lifting one side or the other and continuing upon its stroke the roller 2W-S is withdrawn from the lower lever leaving the aperture between the prongs with one or other of the two lower rollers upheld by the wall of the 'Crosshead'. On the return stroke the said roller 2W-S enters the profiled wider aperture now facing it and moves the Weight to the opposite side of the Gearbox. It must be remembered that during these transitions which only commence just before and terminate just after the mid-stroke position the Gearbox is still locked in its stance.

As best seen, by reference to Figure 4, the roller 2W-5 is maintained ln its elevated position upon Drive-pin 2W4 above the flange of the 'Crosshead' by being upheld by a rising column 2Wll further supported by the coverplate, 2W12, covering the aperture in the forward flanged wall of the 'Crosshead', within which aperture the swinging-over of the lower arm 2W-3b referred to above takes place as the said aperture passes in transit.

(The said Cover-plate is secured to the 'Crosshead C1' by a plurality of releasable securing-means through bores 2W-13 shown on Figure 3). The rising column 2W-il carries in axial alignment with the roller 2W-5 the Power-take-off Drivepin 2W-4 with its backing-flange adhered to riser 2W-11 which continues inwardly, after having served as a dowel, to support the minibearing 2W-5.

SHEET7~ ~ Counter-Balance-WQititMlW l As best shown by Figure 1 a standard rising vertically from the centre of a 'Crosshead C1' is employed to control and coordinate the motivation of this type of Counter-balance-weight when the length of the required stroke falls within the overall width of the Gearbox.

The standard is of a composite construction ideally formed of bar metal of the same gauge as that of the upturned 'Crosshead' Flange; it rise to a height somewhat more than that of the centre of the approved hollow weight lW-8 above the the level of the upper surface of the 'Crosshead' when the said Weight is immediately over the pivotable centre of the Gearbox, to which, as before stated, a suitable addition must be allowed to ensure adequate strength is provided for the securing of the outwardly projecting Spindle 1W-6 secured to the same, as shown by Figure 2, by a threaded end and locknut entering into a threaded bore upon the standard 1W-S shown on Figure 1. The standard is formed of three sections of bar metal 1W-1,2 and 3, the central standard lWl stands upright upon the top of the 'Crosshead Flange' at the centre of the same, a backing bar 2 stands upon the upper face of the 'Crosshead', inwardly of the flange, while 3 rises outwardly of 1. All three are bonded one to the other by metallic adhesive in a vertical stance while other additional securing means, as show, can be employed if required. Prior to these being attached to the 'Crosshead' all three are bored not only to carry the Spindle 6, as shown by Figure 2 but also te Power-take-off Pin IW-4, which if not central to the height of the 'Crosshead Flange' should be as near to it as possible .....the Law of Moments should be borne in mind.Not shown is the backing securing means identical to that employed to secure the upper Spindle 1W-6 which will ensure a secure fastening providing in both cases a simple detachment.

Both the bores for the Driving Means 1W-4 and the Spindle IW-6 are threaded. Both the Spindle 6 and the Driving Pin IW-4 are threaded to a sufficient length capable of extending beyond the different thicknesses of metal into which they are respectively screwed (3 in one case and 2 in the other) plus sufficient to take a washer and a lock-nut.

As best seen in Figure 2;- the Spindle 6 has an overall length that spans the gap between the outside of the standard to the furthest side of the Gearbox while the drum 7c need be no more, in overall length, than the width of the hollow Counter-balanceweight 8. The Spindle 6 is journalled inwardly from the opposite end to that which is threaded a distance equalling the width of the Counter-balance-weight and one bearing 1W-7a sealed externally only, is pressed on using only moderate pressure against the step formed by the journalling: the encasing tubular outer drum is now pressed on to the aforesaid bearing "a" after bearing "b" has been entered into its farther end, again sealed externally ,....however only after a reasonable quantity of lubricant suitable for the said bearings has been injected into the enclosing tube.

As best seen in Figure 3 the Counter-balance-weight is a heavy hollow roller having a central groove in its perimeter whereby it is constrained to maintain its stance upon the top of the Gearbox by the humped-back running-rail lW-9 secured to the top of the same by either metallic adhesive or counter-sunk screws ensuring that the heads of the same are beneath the surface of the rail.

The internal diameter of the Counter-balance-weight must be slightly in excess of the outside diameter of the Roller 7c plus twice the distance of the rise, or fall, of the Gearbox at the extremity of the traverse of the Counter-balance-weight occasioned by its imparted movement as it must be borne in mind that the Driving Means operating upon the rack must rise to disengage and fall to re-engage.

SHEET NO 8 Locking Arms La and Lb The Locking Arms are of composite construction and are a matching pair, the one shown being for the right hand side of the Gearbox. The main part of the body La-1 is of box-steel tube and as shown in Figure 2 has both the front and rear portion cut away at the bottom that a lighter gauge of boxsectioned tube may be supported therein sharing as a common fulcrum the spindle La-li together with the inside of the gusset-plate La-6. This lighter gauge section La-7 protrudes forwardly with the top and bottom of the square section cut away so that a ball-bearing La-12 may be pivoted on Spindle La-13.

This roller La-12 is to make contact with the Cam, or Cams, upon the 'Crosshead C1'.

The gusset-plate is secured to the side of the main part of the body La-l by set-screw La-8 and is slotted for the purpose of adjustment to the lower arm La-7 and shares the common pivotal means La-il. It is also adhered to the bottom arm La-7 by metallic adhesive and further strengthened by a further setscrew La-9. The upward extension of the Locking Means La-2 is of square section aluminium of a gauge that fits snugly into the main body La-l. At its upper extremity and facing forwardly in the same direction as the lower arm La-7 is fastened the restraining catch La-3, secured by set-screws La-4a and b. The apex is drilled inwardly on both locking-arms and a bent stout steel wire angled-hook, La-5, turned away from the catch La-3 is secured in place by metallic adhesive.

Figures 3,4 and 5 show details of the supporting brackets La-lO employed for the pivoting means of the two Locking Arms upon their fulcrum Spindles La-ll. The two opposing brackets are mounted upon the decking above the Bedplate whereby the roller La-12 upon their bottom arms is fractionally above the level of the top of the 'Crosshead' and in line with the centre-line of the same whereby contact can be made by each with the Central Cam C4 and their respective end Cams 7 and 7a.

Connecting the two upper extremities of the Locking Arms by means of the angled-hooks the extending spring restraining-means La-14 is employed whereby the two Locking Arms are prevented from over-balancing backwards if the appliance is run at too high a speed.

The albut immediate locking of the Gearbox by either of the two Locking Arms is positive and occasioned by the out of balance stance both tending to fall forward and engage; in fact when disengaged the upper part of the restraining catch is resting against the Latching Spindle adjacent to the same as can be seen in Figure 1 and subsequent Drawings. In consequence when the opposite side to one is released due to the pressure exerted by the Counter-balance-weight the appropriate Spindle moves through its short downward arc, the Locking Arm, now the restraint is removed, engages with the Spindle and an immediate locking contact is made; this is aided by the nylon or hardened steel roller rotating upon the Spindle. Since the contact is tangential to the roller the hold is certain.However the tangent in contact with the roller is minimal and is quickly lost in the chamfered curve of latching means on La-3. In consequence only a minute upward and backward movement of the Locking Arm destroys the restraining secant; in consequence the release is as rapid as the locking. If the appliance is running at only eight revolutions per minute the release of one side and the locking of the other takes place in under half a second.

Not shown hitherto is the provision of two rubber-capped columns rising from the deck of the Bedplate behind the Gearbox immediately beneath the rear extremities of the Latching Spindles LSa and b as shown on Sheet 4, Figure 8, being indicated on Sheet 9, Figure 1 by broken line means, serving a dual purpose (a) to prevent the two Driving Sprockets tending to bite too deeply into mesh with the rollers of the rack upon the 'Crosshead' and (b) to deaden the noise that would otherwise result.

SHEET 9 Fiure 1 Figure 1 shows an End Elevation of the Gearbox mounted on the Bearing Means D4 as shown on Sheet 2 employing 'Crossheads' Cl1 2 or 3; the Locking Arms and Counter-balance-weight being omitted that a clear illustration might be given to Figure 2 which shows a cross-section of the 'Crosshead C3' it being a composite construction employing both angle and Zed-section extrusion bonded one to the other giving a two tiered rackingmeans wherefor the two Driving-means differ in diameter. By such means the two imparted strokes of each reciprocated cycle can differ as to their respective power/velocity ratios as required; both tiers can be walled around and given cover units as variants of the oil-bath previously advocated.Such an Embodiment would meet the need of operating "laying-up" or "cutting-tables" requiring however an unpowered run beyond the length of powered motivation to come to a braked stop calling, in consequence, for "holding-means" (hydraulic) to prevent the full pivotation of. the Gearbox until the table commences the return due to recoil of the braking-means since during the "unpowered run" the momentum of the table, with its loading, is arrested and a return commenced by pneumatic/hydraulic buffering-means the return initially commenced due to the expansion of the compressed air after the table has come to rest.

If the two Driving-means are fitted with either ratchet or dogclutched hubs and either is brought into contact with its racking-means before the table has come to rest they would free wheel or over-run until the return speed of the table and that of the wheel's periphery coincide. It will be seen that such buffering-means will be required at both ends of the table, ideally adjustable as the length of the over-run can vary with each particular length of work performed and too the resultant momentums occasioned by the same.

Figure 3 (half-scale Plan) shows the Bed-plate of the pivotal Bearing Means D4; Figure 3a is an end elevation of same showing corner-shimmering-pads.

Figure 4 shows by Plan and Elevation an alternate Power-output drive-pin for attachment to the underside of the lower of the two 'Crossheads' as shown on Figure 2.

SHEET 1Q To take full advantage of the long strokes made available by this reciprocated motion whether for pumping water or to impart hydraulic means of power twin single action pumps are advocated as the cost of conventional single or double-action pumps would be excessive. A further advantage is that the servicing or renewal of worn parts would be less time consuming.

The great advantage of narrow bore, long stroke pump is that the back pressure is directly related not only to the head delivered but also to the area of the piston. The volume pumped however is the area of the piston multiplied by the length of stroke.

It can be seen therefore that the volume ejected by a large diameter piston through a relatively short stroke can be equated by a longer stroke imparted by a smaller diameter piston, which, due to the proportionally reduced back pressure can be pumped to a greater height.

Following the example of hydraulic engineering practice a pump employing a piston of a ram-like nature is employed. By its use no contact of the piston with the cylinder walls is called for thus reducing frictional losses. The said cylinder can be of any material capable of withstanding the necessary internal pressure while the piston needs to be of a rust-proof material and capable of being finished to fine limits. Modern technology has developed plastic tubing, with a polished bore, capable of withstanding seventeen atmospheres of pressure while aluminium rod or tubing is now available in various diameters accurate to between one or two places of decimals in millimetres, both meeting the necessary qualifications.The piston common to both opposed cylinders, if hollow, needs to be capped while whether solid or hollow both ends require to be given a gentle but pronounced chamfer whereby the seals of the glands will not be damaged when the cylinders are being slid over the piston-ends during assembly.

Figures 1 and 2 detail the forming of a saddle la to uphold by bored means the Piston 1 secured thereto by Drive-pin 8. Two further vertical bores ib and c are the means whereby the saddle is secured to the top-plate 2a of a Linear -bearing 2 (as shown by Figure 3), being a cross-section on the line a - b as shown on Figure 4, by suitable means. This same Figure 3 shows the rail of the Bearing mounted upon a Composite Base 3 at the centre of its length which should be no shorter than three times the length of the imparted stroke required, plus that of the Linear-bearing.As shown by Figures 3 and 4 the basic longitudinal support is of box section steel to which side wings 3a and 3b are affixed by pop-riveting, or other satisfactory means - the same supporting a length of channel extrusion for the support and alignment of the two opposed pump-barrels; said channel reduced in height on one side for the length of the 'crosshead' separating pump gland-boxes whereby clearance is given for the drive-pin 8 extending transversely from the aforesaid saddle. The above preferred embodimental means can be modified to meet the loadings required.

The centre of the length of the base defines that of the linearbearing at the mid-stroke position of both pistons. Accordingly the length of the rail of the Linear-bearing must be equal to that of the required stroke plus a fraction over the overall length of the bearing. The two ends of the rail are blanked thus forming an oil bath of the upturned rail for lubrication means. In securing the rail it is imperative that its Centre line conforms with that of the base which, later, will be mounted, parallel in both the horizontal and vertical planes, with the 'Crosshead' of the Reciprocating Unit being supported by the Brackets shown on Sheet 1. In mounting the same the heights of the two Driving Pins (that of the Driving Means and that of the pump's 'crosshead') must conform whereby the two may be linked by a common sleeve.

Beyond the two terminations of the 'Crosshead' rail the length of channel 4 of a suitable gauge of web and side height is secured to the common base both in common centre alignment with the rail of the aforesaid bearing whereby the piston Pt-l may at all times, throughout its length of stroke, be parallel to not only the side walls of the channel, but also to the inside of the channel 4 web. As shown by Figure 3 the length of channel will support the pump barrels by means of a plurality of flanges 5 along their length.

The separation of the two opposing Gland-flanges 5 and 6 is shown on Figure 4 and both serve to uphold and secure a coverunit 9 to protect the lubrication means from dust and other contaminating substances.

As best seen by the end elevation of the same upon Figure 3 this is supplemented by a moveable lower screen 9a supported and reciprocated by a collar welded to the same upon the Drivepin 8.

On Figure 4 the fixed cover-screen is indicated by broken lines...it will be seen to be secured to the inward-facing frontal flanges of the Pump glands 5 and 6 by threaded means 7.

SHEET 11 (continuation of Sheet 10) PUMPS AND GLANDS As previously advocated the employment of modern plastic materials are ideal for the formation of the Gland and Pumpbarrels of the proposed twin single-action Pumps. A variety of plastic extrusions and gauges of sheet-plate together with piping capable of withstanding pressures of 18 kilograms per square centimetre are now available. Light but strong, capable of fine machining to acceptable limits they are readily weldable without excessive heat. Further, both their internal and external surfaces are glass smooth whereby not only are internal frictional losses reduced to a minimum but face to face sealing can be accomplished with but a smear of rubber adhesive, the joint being readily broken when necessary, and readily cleaned for reassembly.

Figure 5 is a frontal elevation of one of the two opposed frontal Gland-flanges, being identical in external measurements to that shown upon Sheet 10 in Figure 3. As shown on Figure 5, the four corner bores should be taken to be either 5, or 6a, b, c and d.

The Gland Unit as shown on Figure 6 consists of three such Flanges Gl, 2 and 3 all bored as advised above. From left to right the first, third and fourth (the Pump-Gland-flange PG5) are all centrally bored to a slide-fit for the piston Pt 1. The second however is bored centrally to a wider diameter than that of the piston whereby, throughout its width, whereby a chamber is formed around the piston.

This flange GF2 upholds the reservoir G2a which screws into a threaded vertical bore G2b which continues with a narrower diameter to the central horizontal bore, a sealing washer being employed. The screwed in reservoir has through its collared threaded bush a similar bore to that given to the flange.

Flange G1 is recessed inwardly and Flange G3 on both sides for U seals; opposing seals having contact with Flange 2 and the inward seal of Flange G3 with pump-gland terminal flange PG5.

As best shown by Figure 7 the pump barrels PB 1 and 2 are both welded to their respective Pump-Gland master-flanges PG5 and 6 together with a backing supportive pressed-on bushing PBla and b which circumvallation ensures an expanded circle of plastic weld above that offered by the pump-barrel. The said bushing while welded to the pump-barrel around its rearward vertical edge can be further reinforced by pre-drilling the same around its perimeter and pipping the pump-barrel through the same whereby molten plastic may have ingress through the bores and into the perimeter of the said pump-barrels enshrouded by the bushings.

The outer termination of the said barrels as shown by Figure 7 are capped by terminal Flanges TF bored for the securing thereto of valve-assemblies or other necessary connective means as shown by Figure 8.

At intervals between Gland-flanges PG 5 and 6 and their opposing Terminal Flanges additional Flanges may be secured to the pumpbarrel to contain the thrust imparted by the piston; these additional flanges are identical in external measurements to the Terminal Flanges having a central bore equating to that of the outside diameter of the pump-barrel to which they are welded with a stance conforming to the channel supportive means whereby the pump-assembly is a slide-fit upon the piston and between the side-walls of the channel, the frontal Gland-flanges butting against the rail of the Crosshead defining its full entry.The said Gland and Terminal Flanges are secured to the side walls of the channel by threaded means, likewise, the intermediate flanges can be welded to the pump-barrels and secured to the side-walls of the channel if the internal pressures within the barrels call for additional support, or as shown by Figure 7 where PFBa and b denote a minimum of two additional flanges and PF5c pressure blocks secured to the channel walls by releasable means.

Figure 8 shows a frontal elevation of a terminal flange, either TF 5 or 6 showing threaded bores whereby attachments may be secured there either by set-screws or studs and nuts.

The dismantling of either pump for attention to the seals, or to replace the piston or the Linear-bearing is a simple matter providing the pump assemblies are withdrawn by sliding along the base of the supportive channel.

The object of the reservoir G2a is to contain a liquid the weight of which will supplement the prevailing atmospheric pressure ensuring thereby that air cannot find ingress into the cylinder as during the intake stroke the Gland-seals of both G1 and G2, under only atmospheric pressure, are virtually inoperative. If then the chamber formed by Gland flange 2 is charged with a fluid with a viscosity greater than that of air this leakage is prevented with minimal pressure upon the piston.

By comparison the normal stuffing-box type of piston-rod seal could exert an unwarranted pressure upon the same.

Oils such as castor, glycerine or olive, none of which are dangerous to human or animal health could be employed but to avoid the possible need to replenish the supply water from the delivery line of the pump could be delivered to the aforesaid chamber by a capillary tube, whereby the pressures both within the pump and within the gland-box would equate at pressures above that of the atmosphere.

As advocated on Page 6 wherever possible inlet and outlet ports together with the necessary valves should be in line with the pump-barrel and although this is not always possible where bends must be employed the Valve-assembly Va as shown by Figure 9 on Sheet 11 is advocated. Two bends are cut along their centrelines as shown by the sectionalised drawing and two opposing halves are welded along the seams, the common flange faced up and drilled for means of attaching the same to the Terminalflange of the pump-barrel TF as in Figure 8. The two opposed mouths are fitted with bushed-flanges the said bushings internally threaded, the flanges being welded to the open mouths.The two valves are identical one to the other and are threaded into the said flange-bushes being sealed thereto by proven sealant means; the upper valve V1 being threaded home by means of the transverse valve-stop while the lower valve V2 employs a transverse groove across the outer face of the housing wherefore the sectionalised groove is not hatched on the drawing.

SHEET 12 AN HYDRAULIC ENGINE This employment of the invention is but one of the several means whereby a given reciprocated motion can be converted into a rotating powered-drive thereby offering a higher efficiency ratio than that imparted by a crank.

The medium employed to reciprocate a necessary 'Crosshead' or in certain cases two separate 'crossheads', one each side of the Gearbox, are of little consequence whether it be by Hydraulic, Pneumatic (steam or compressed air) with appropriate valve gear, by hand-lever or foot-pedal. Whilst each may call for varying means of control or application none would alter the basic principles of the invention.

As best shown by Figure 1 the Engine utilises a Gearbox G and 'Crosshead' C as formerly disclosed. In this embodiment the Gearbox is given a fixed upright stance wherefore the Counterbalance weight, Locking Arms and Spindles are not employed; likewise the 'Crosshead' is given no central or terminal Cams.

No internal balance-weight is required. The bases of the two shaft-bearing means Gllc and Glld are both bored through providing securing means to the Bedplate B.

The Gearbox will, when assembled, be upheld by the angular Backing-plate Gllc, by the three-fold means as previously employed, refer Sheet 2, Figure 3, Bores (for studs D7a, b and c) each concentric around the axial bore) the backplate of the Gearbox Gllb being bored and threaded, with a minimum of three bores upon a common pitch circle evenly spaced around the necessary bore for the dual Driveshaft-bearing D5b. The Gearbox support-plate Glic is likewise bored on the centre-line of the said axial bore to a common diameter giving a press-in fit to the Bearing(s) D5b, and too, the concentric clearing bores whereby set-screws may secure the Gearbox to same.The distance between the centre of this bore and the base of the angular Backing-plate can vary the criterion being that when mounted upon the Bedplate the two Driving-sprockets Gl3c and d are both in mesh with their respective roller-chain racks upon the 'Crosshead' C.

The Driven Shaft D5a is journalised to a press-fit to the Bearing D5b while internally the hub of the master-driver G12 is bored to a slide-fit upon the shaft and secured thereto by convenient means. The shaft is likewise journalised to give a slide-fit to the Flywheel D6 and a seating prepared for keying the same and again for the bearing upheld by bearing-column Glld, said bearing D5c.

The Gearbox is secured to the Bedplate by releasable means on the centre-line of the same parallel to the line of the 'Crosshead', which as in the prior Embodiments is mounted upon Linear-bearings.

The two sprocket-drivers Gl3c and d are secured to hubs fitted either wit ratchet means or dog-clutches which drive in opposite directions from each other whereby when the 'Crosshead' is motivated one Driver is in a state of drive while the other free-wheels. It will be seen then that if the 'Crosshead' is moved through its full length of stroke due to the internal gearing within the Gearbox the driven shaft D5a is compelled to rotate receiving a further impetus to revolve in the same direction as the 'Crosshead' returns to its original position.

If the 'Crosshead', for any reason, ceases its reciprocations the flywheel upon the shaft will continue to revolve until its momentum, or that of a driven appliance, is exhausted without in any way affecting the stationary 'Crosshead'.

The 'Crosshead' C is powered by two opposed Hydraulic Rams as detailed on Sheets 10 and 11 (defined as R4 on Sheet 12) showing an end elevation of one terminal flange while the truncated rising pipe R1-4 (refer Figure 2), as indicated by the opposed arrows above, serves as both an inlet and a discharging means.

Figure 2 is a schematic portrayal of the means of powering the Hydraulic Engine by ram-pistoned cylinders similar to the Rams operating the 'Crosshead' of the same, the pumps being powered by suitable means, a water-wheel for instance, the pressurised fluid employed being fed by two separate closed-circuit means.

As shown Pump 1 powers Ram 4 while Pump 2 powers Ram 3. As the latter is being charged Pump 1 is withdrawing the charge from Ram 4, since the Rams are subordinate to their respective Pumps.

It will be noted that the term similar" and not identical was employed above. They must necessarily be identical in their volumetric capacities but can be given differing diameters as to their rams and length of operational strokes. In consequence a type of gearing can be incorporated in the drive.

SHEET 13 It will be noted that no valves are employed in the closed circuit system shown on Sheet 12. However in certain cases it may be desirable not only to operate an Hydraulic Engine at a distance from the Prime-Unit but to also deliver water, at a low head, to a site adjacent to the same, which need could be met by the following means.

Figure 1 shows a schematic Plan of this embodiment of the Invention where cylinders 1 and 2 share a common piston Ptl operating pumps powered by a Prime-Unit according to the foregoing pages of this Specification differing only in the fact that the said cylinders l and 2 are fitted with inlet valves lV1 and 2 and intake piping (not shown) to the water supply, the said cylinders being operated via wrist or drive-pin WP1.

Cylinders 3 and 4 operate their common Piston PT-2 and by wrist pin WP-2 reciprocate the 'Crosshead' of the Hydraulic Engine (refer Sheet 12) the said cylinders being equipped with the necessary inlet valves, A3 and A4 respectively and exhaust valves B3 and B4, which reference numbers not only denote the valves proper but also their replaceable valve seatings.

As shown the two sets of cylinders are connected by the pipelines la and 2a both being given a rise and fall in their length at the apex of which air-bleed-valves are incorporated in the lines (AB) as it is essential to free the system of the oxygen absorbed by water running when exposed to the atmosphere and which, under pressure, can separate out and lower the efficiency of the system.

Figure 2 shows the necessary valve arrangements. It will be noted that Valve A has a greater diameter than the lower Valve B (the same applying to the valves in Cylinder 4 hence their references A3, B3 and A4, B4) wherefore whenever cylinders 3 or 4 are under compression no fluid or trapped air can lower the partial vacuum responsible for the charging of cylinders 1 or 2 by atmospheric pressure.

Figure 2 also shows a partial section of the cylinder-barrel CB further revealed by Figure 3 being a cross-section on the line a-b on Cylinder 3C, Figure 2 showing it enclosed in a length of extruded box-section which houses the terminal flanges TF and the Glands, which although not shown, follow the design as those depicted on Sheets 10 and 11.

The cycle of operation is as follows;- As the Piston Ptl is operated within the two clyinders 1 and 2 by the reciprocation of the 'Crosshead' of the Prime-Unit at a constant velocity and pressure each are charged in turn by atmospheric pressure whilst the contents are, on the return stroke, alternatively forced into cylinders 3 or 4 thus operating Piston Pt2.

The charging of either of the two cylinders 3 or 4 also ensures the closure of the larger diameter Valve A and the opening of the corresponding exhaust Valve B. The enforced closure of Valve A ensures no water, or air if present, can return to either Cylinder 1 or 2 which are contemporaneously being charged by atmospheric pressure. The enforced reciprocating movement imparted to the Piston Pt2 operates the Hydraulic Engine the Wrist-pin of the Piston being linked to that of the 'Crosshead' of the same. The two cylinders 3 and 4 share a common discharge.

It can now be seen that a new and improved reciprocating motion has been provided and that the objects, earlier enumerated, have been accomplished. Although five preferred embodiments have been illustrated and described in considerable detail the present invention is not to be considered limited to the precise constructions shown or to the purposes of employment depicted.

It is intended to cover all adaptations, modifications and uses of the invention which come within the scope of the appended Claims.

Claims (21)

1. A device for converting continuous rotary motion into reciprocating motion comprising: (a) a bedplate upon which a gearbox is pivotally mounted, said gearbox being provided with an input shaft, the gearbox being pivoted about the axis of said input shaft, said gearbox also having two output shafts whose axis are parallel to that of said input shaft, the output shafts rotating in opposite directions when the input shaft is rotated in one direction, the output shafts having sprockets mounted on and rotating with them;; (b) a linear rack mounted on said bedplate for reciprocating motion in a direction perpendicular to the axis of the output shafts, the sprockets on said output shafts being capable of meshing with the rack, the racking means being formed of roller-chain the arrangement being such that when the gear box is pivoted in one direction one of the said sprockets meshes with the rack and when the gearbox is pivoted in the other direction the other sprocket meshes with the rack so that when the input shaft is rotated in one direction the rack is moved in one direction by one sprocket, the gearbox pivoting to disengage one sprocket from the rack and engage the other when the rack reaches the end of its travel thus driving the rack in the opposite direction, means being provided to pivot the gearbox when the rack reaches the end of its travel thus producing continuous reciprocating motion of the rack as long as the input shaft is rotated.

2. A device for converting reciprocating motion into continuous rotary motion comprising: (a) a bed plate on which a rack is mounted for reciprocating motion, the rack being formed of roller chain; (b) a gearbox mounted on said bed plate, the gearbox having two input shafts and one output shaft, the axis of said shafts being perpendicular to said rack, the input shafts having sprockets in continuous mesh with the rack, the gearbox being arranged so that each input shaft rotates the output shaft only when driven in one direction, the driving directions of the two input shafts being opposite one to the other, the input shafts free-wheeling when driven in a direction opposite to their driving direction, the direction of rotation of the output shaft being the same when each input shaft is rotated in its driving direction; the arrangement being such that when the rack is moved in one direction one input shaft rotates in its driving direction to rotate the output shaft in a predetermined direction and when the rack is moved in the opposite direction the other input shaft is rotated in its driving direction thereby rotating the output shaft in the same predetermined direction.

3. A device according to Claim 1 or Claim 2 wherein the gearbox includes internal sprockets to which the two input/output shafts which drive, or are driven by, the reciprocating rack and the input/output shaft is driven in, or driven by, continuous rotary motion are attached, all three sprockets being connected by a loop of roller chain, one of the internal sprockets mounted respectively on the two parallel internal shafts (each mounting externally of the Gearbox the Driving or Driven Sprockets alternatively engaged with the rack) being outside of the said interior loop of drive-chain wherefore the said two shafts are rotated in opposite directions one to the other, the gearbox also including idler sprockets to guide the chain around and past the sprockets attached to the input/output shafts;;the arrangement being such that when the rack is moved in one direction one input shaft is rotated in its driving direction rotating the output shaft in a predetermined direction while when the rack is moved in the opposite direction the other input shaft is rotated in its driving direction while the momentum of the driven part maintains the drive during the brief interval of time taken to effect the transfer of directional drive.

9. A device according to Claim 1 where the gearbox is pivoted either by mechanical or hydraulic means directly or indirectly controlled by the reciprocating rack whereby any desired length of reciprocated stroke can be met.

5. A device according to Claims 1 or 2 where the rack has a wrist-pin secured thereto the said pin protruding parallel to the twin output/input shafts of the gearbox providing power-input means in the case of Claim 2 and power-output means in that of Claim 1.

6. A device according to Claim 1, Claim 3 when dependant on Claim 1 or Claim 4 wherein the gearbox possesses two sets of latching-means that are engaged by corresponding locking-means when the gearbox is pivoted into engagement with the rack, the locking-means preventing the gearbox from pivoting prior to the termination of a stroke.

7. A device according to Claim 6 wherein the gearbox is unlocked at the end of each stroke by cam surfaces upon the rack that disengage the respective locking-means from the latching-means thus allowing the gearbox to pivot.

8. A device according to Claims 1 or 2 where the rack is walled around to form a common oil-bath for the rack having covers thereon to protect said lubricant from dust and airborne fibres.

9. A device according to any one of Claims 1-8 where the said cover means comprise a fixed cover-plate supported off the bed-plate by bracketed means said cover-plate having slotted means whereby the twin driving-wheels external to the gearbox may have access to their respective racks while further slotted means permit the entry of the aforesaid locking arms to contact the release cams.

10. A device according to Claims 8 and 9 where protective means are given the two exterior sprockets of the gearbox by a cover-plate pivotable upon the axis of the input/output shaft, the top and two side walls having light-weight Zed-section flanged surrounds maintained in close approximation to forward face of gearbox while the bottom of said cover-plate has a forward facing flange maintained in close approximation to the cover-plate of the racking-means.

11. A device as claimed in Claims 1 or 2 where the respective gearboxes are fitted with means for both lubrication and drainage.

12. A device according to Claims 1 or 2 where the input output shaft-bearings have means of lubrication replenishment.

13. A device according to any one of Claims 1-12 applying thereto where the rack operates an hydraulic ram-type pressurising unit by sleeve-connecting means said racking-means having central-drive-pin projecting perpendicular to forward face of same.

14. A device according to Claim 13 where the hydraulic pressurising unit comprises twin opposed cylinders maintained in common alignment one to the other within a length of channel, or similar supportive means such as extrusion by means of a plurality of identical flanges centrally bored to outside diameter of said cylinders being slip-fitted within said channel being secured to channel walls by releasable means; said flanges being welded to said cylinders including terminal flanges at both ends of same all bored upon a common-pitch-circle for the securing thereto of gland-units inwardly of said cylinders and valve boxes or suitable connecting means in lieu of same being attached to the outer ends by releasable means, said opposed cylinders separated for the reciprocation of a saddle centrally and longitudinally bored to maintain a piston, common to both cylinders, in alignment with same, said piston only minimally smaller in diameter than bores of aforesaid cylinders, said saddle fitted with protruding drive-pin perpendicular to same and inward-facing aforesaid supportive channel, inward facing channel wall lowered for required length of stroke whereby drive-pin of said piston may be connected by drive-sleeve to drive pin of reciprocated or reciprocating rack as detailed in Claims 1 and 2.

15. A device as claimed and detailed in Claim 14 where the gland-units are formed of three flanges identical in plan to the cylinder-supporting flanges as in Claim 14 but of thicker gauge; both the outer and inner flanges are centrally bored to a slip-fit to the piston while in addition the first is machined on the inner side to accommodate a U-seal whilst the third, or inner, flange is machined for U-seals on both sides; the central flange is bored to a larger diameter than that of the piston whereby a chamber is formed around the piston, care being given to leave a sealing edge for the inward facing seal of the third flange; said central flange has a vertical rising bore enlarged and threaded adjacent to the top of same for the attachment thereto of a fluid reservoir or a connection to the delivery line whereby the chamber around the piston, due to the wider bore, may be pressurised with fluid thus preventing the entry of air into the cylinders; order of sealing being Seal 1, (outer seal) sealing against piston and forward side of central flange; forward seal of third and inner flange sealing against inner side of second or central flange; inner side of third flange sealing against forward face of forward cylinder terminal flange and piston, the arrangement being such that the device as claimed in Claim 1 can operate pumping means as claimed in Claim 14 and by closed circuit means power a twin cylindered Hydraulic Engine as claimed in Claim 2 by repetitively powering one cylinder of the engine while withdrawing the late pressurised charge from the other whereby the torque of one driving shaft can be used to power another at a distance without the employment of mechanical linkage.

16. A device as claimed in Claim 2 where the powering means can be either delivered by hydraulic or pneumatic means delivered at a maintained pressure and volume the same controlled by valve-gear operated by the movements of the reciprocated rack.

17. A device as claimed in Claim 2 where the output shaft is powered by manual reciprocation of the rack.

18. A device as claimed in Claim 2 where the two drive shafts protruding from the frontal face of the gearbox are extended rearwardly of the same and driving means secured thereon said driving means acting upon secondary racking means mounted on the bedplate for reciprocating motion the two racks set in opposition one to the other wherefore when one is fully extended in one direction the other is fully extended in the opposite direction, where each of the racking means are operated by foot-pedals, each pedal having a foot-retaining strap, the said device having an extended bed-plate whereon suitable seating can be offered the operator(s).

19. A device for converting rotary motion to reciprocating motion substantially as herein described with reference to the accompanying drawings.

20. A device for converting reciprocating motion to rotary motion substantially as herein described with reference to the accompanying drawings.

21. A device, a modification of that claimed in Claim 15, where the closed circuit means as claimed therein are replaced by fresh charges of liquid propellant (water) by means of the compressor cylinders being fitted with non return inlet valves, the contents of the same being expelled during each pressurised stroke and the contents being forced in turn into the cylinders of the driven appliance thus operating the same by alternative driving strokes of determined length: the said cylinders, each being fitted with dual valves upon a common stem whereby the entry of the fluid opens the inlet valve and closes the opposing outlet valve: at the conclusion of the said stroke the opposing piston exerts pressure on the late powered piston and the resultant pressure closes the return to the inlet valves of its opposite number, opening in consequence, the oulet valve whereby the contents of the said cylinder are discharged. The disparity of valve areas upon the common stem ensure the alternate closures and openings of the two valves whereby water having transmitted power through a determined distance can be discharged as convenient.