AU593301B2 - An improved non rotary air driven sheep-shearing machine - Google Patents

Description

I This docurneot ~Ontadna b Mdo U"K 3.t~t49, Wd it, 00N ,11AUSTAI PATENTS ACT 19525 jFrm1 *E SPECIFICATION (ORIG INAL) PATE NT OFFICE PATENT OFF1 FOR OFFICE USE 1,kult..hlnui' 4 ou Short Title: Int. CI:- A 49 a 7/9 Z e Application Number: -l ~sZ96) Lodged: 7tomplete Specification-Lodged; Accepted: PACtrty; Lapsed, Published: 7- w.- Related Art: Nbrow of Applicant: A~orass of Applicant: Actual Inventor Address for Service: Complete Specification TO BE COMPLETED BY APPLICANT ROBERT ARTHUR ROSE 20 STANHOPE ROAD, KALJAMUNDA 6076 ROBERT ARTHUR ROSE AS ABOVE forth. invention entitled- AN IMPROVED NON' ROTJARY A:IR DR!VEN 111' j -SHEEP-SHEARING MAC81INE The following statemer,'t Is a full description of this Invention, including the best method of performing It. known to me- *Note The description Is tq be typed In double sl*cIng, pica type face, In an aresj noat exceedintg 250 mm In dsp4h and 160 mm In w tovigh White paper o good quality and it Is to be lnsewed IMpI is fri 1459978-L Printed by C. J.T"O*r ,Commonwealth Government Printer, CanberrA i -2- CONVENTIONAL SHEARING MACHINES Shearing Machines in common use are driven either individually by overhead motors or collectively by a horizontal overhead shaft which, in turn, is driven by an electric motor or an internal combustion enoine. An articulated rod-in-tube driving shaft connects the overhead drive with the handpiece which contains the shearing head.

An overhead friction-wheel clutch operated by a suspending cord engages and disengages the driving shaft from the power source to start and stop the operation of the handpiece.

The handpiece contains a crank-wheel with a crank-pin which engages with the rear end of a pivoted "driving fork", so named because its front end forks horizontally to provide twin sockets for two load-equalising yokes. Each yoke is also forked and has a projecting conical pin under its outer arm which engages with a socket in an outer tooth of the shearing cutter.

As the driving fork is pivoted by the crank-pin the a shearing cutter moves to and fro across a shearing comb which is fitted to the front of the h %ndpiece.

A lateral pressure called "Cutting tension" is applied to the driving fork to hold the cutter in sliding contact with the comb. This tension is applied lby a hand-adjusted nut which screws onto a hollow guide post 23 prcjecting upwards and backwards from the front end of the handpiece. The guide post contains a guide sleeve which is forced inwards by the nut against the outer end of a tension Sin. The inner end of the pin is seated in a socket which co eg is placed close to and forward of the pivt-point of the driving fork.

0 soc Tension is applied to the cutter in the required .d odegree by screwing the hand-nut inwards.

Many attemps have been made to improve the shearinag handpiece by directly attaching motors of various types to S35 handpeces in order to eliminate the cumbersome and restrictive driving-shaft, but such attemps have not gained wide acceptance because of the added weight or bulk for the operator to manipulate.

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-3- Apart from the inconvenience of the driving-shaft, however, rotary motion occurring within a handpiece has disadvantages in itself. The twisting force has to be restrained by tight gripping of the handpiece, and if the handpiece is dropped or laid on the floor whilst the motor is running, it will roll out of control on the floor, sometimes breaking off a tooth from the comb. Unneeded extra tension is required to overcome counter-thrusts caused by rotary motion within a handpiece, ti.reby increasing the working load and the tendency towards rverheading the cutter and the comb.

The inventor had decided that an improved shearing handpiece should desirable include the following features:the motor should be non-rotary and air driven; the motor housing should be either directly attachable to, or else made in one piece with, the handpiece; the width of the motor should be less than the 0 width of the average fist gripping the handpiece; .20 the lower extremity of the motor must not be below the shearing comb; the control mechanism must be directly attached to the machine; the weight of the machine (motor plus handpiece) must not exceed the weight of handpieces in common use.

FEATURES OF THE INVENTION With the object of achieving at least some of these *t features in a shearing handpiece, there is provided a pneumatic operated shearing handpiece having a drive arm supported in a housing for pivotal movement about a pivot r t l axis intermediate the length thereof, said drive arm being t adapted to support a cutter element at one end to oscillate about said pivot axis, a cylinder mounted in the housing with the axis thereof extending transverse to the direction of length of the drive arm, a double ended piston within the cylinder mounted to reciprocate therein between respective closed ends of the cylinder, said piston having a recess in AL Disk 0063/1.41 I J-^ -4the periphery thereof with the other end of the drive arm extending through the cylinder and seated in said recess whereby the drive arm affects said oscillation of the cutter element in response to the reciprocating of the piston, respective drive chambers being formed between the closed ends of the cylinder and the respective ends of the piston, and valve means to control selective supply of compressed air to an exhaust from said chambers to effect said reciprocation of the piston, said valve means comprising a pair of mirror image valve chambers arranged co-axial to a common actuating rod extending into each valve chamber and axially slidably supported in a wall sealably separating said valve chambers, each valve char"ber being (associated with a respective one of the drive chambers, saic actuator rod having mounted thereon in each valve chamber two valve elements in a fixed axial spacing each adapted to independently selectively sealably close respective ends of an air transfer chamber in continuous communication with a *respective drive chamber of the cylinder adjacent the closed 20 end thereof, a compressed air supply port and an air exhaust port in each valve chamber arranged so the air exhaust port is isolated from the transfer chamber and the air supply q port is in communication with the transfer chamber when the actuation rod is in one axial position relative to the wall and vice versa in an opposite position of the actuator rod, and so the arrangement in the respective valve chambers is the reverse for each axial position of the actuator rod, and an actuator piston fixedly mounted on the actuator rod in each valve chamber and sealably slidable therein, the respective valve chambers on one side of the actuator piston S. communicating with the air supply port and on the other side S with a vent passage, the vent passage being selectively communicated with atmosphere and the drive chamber associated with that valve chamber at the respective ends of the movement of the piston in the cylinder.

Dsk 0063/1.41 4f 1 3 The weight of the handpiece with the cylinder and piston made of aluminium, and a handpiece housing generally made of steel is within the expected limits.

A complete handpiece housing and motor made of a modern plastic such as polycarbonate by an injection-moulding is also possible.

When the motor is activated the drive pistons and the valve means interact pneumatically to reciprocate each other and thereby to pivot and reciprocats the drive arm, the rear end of which engages with the drive piston and the front end with the shearing cutter. The front end of the drive arm and the load equalising yokes fitted to it are similar to those in conventional handpieces.

Separate interchangeable drive arms are made to fit and operate with wide or narrow cutters and combs of standard types. In operation the drive arm and the shearing cutter are made to reciprocate in the same parallel plane with the driving piston and the valve means.

A control lever is attached to the front end of the 20 motor housing and operates in conjunction with an air-supply valve.

Lubrication of the machne is provided by an airline lubricator which is placed overhead on the air supply pipe and from this a flexible air hose of any required length leads downward to a connection placed on the rear end of the motor.

A detailed description of the shearing handpiece follows, with reference to the enclosed drawings.

Figure 1 is a plan view, reduced from actual size, which shows the shape of the handpiece and the positioning i of its working parts viewed from above; Figure 2 is a side view on the same scale as Figure 1, showing a cross-section of the handpiece and a view of the motor with the right-hand side-plate removed. Section AA shows the front of the motor with the handpiece cut off, exposing the driving passage, the driving shoe and also showing the control lever in position; Disk 0063/1.41 0 0e 7'< a a- Figure 3 shows an enlarged horizontal cross-section of the working parts of the motor and the rear end of the driving fork and also shows the air escape passages.

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Figure 4 is a cross-sectional view of the valve parts.

Figure 5 is an enlarged plan view of the motor revealing the air-connection, the air-supply valve, the control lever and the air pressure passages.

Figure 6 shows the right-hand side-plate with its airpassage cavities in concealed outline, and a cross sectional view Figure 7 shows the separated parts of the cutter-tensioning device.

Identical pairs of parts are given the same number, followed by the letters L or R, where necessary, to indicate left or right hand location when viewed towards the front, or forward, end of the machine which is the shearing head.

The terms "inward" or "outward" mean towards or away from the longitudinal centreline of the machine respectively and "above" or "below" apply as the machine rests on a horizontal surface.

The handpiece body has an internal bore which may be round or rectangular in cross-section.

The driving fork has a pivot socket placed about midway in its underside.

The pivot socket engages with a pivot post which is screwed into the underside of the handpiece body from outside, and projects into the bore.

The rear end of the driving fork is shaped to pivot within 1, 7 a "driving shoe" which is retained on the driving fork by a pin (6P).

The end of the fork, with the shoe, fits into a rectangular "driving slot" (19) which extends through the central diameter of the driving piston The driving slot has close side-clearance with the shoe and sufficient end clearance above and below to provide for vertical selfadjustment of the driving fork to adapt to combs and cutters of varying degree of wear as well as to provide air passage through the piston. The driving shoe is positioned centrally within the driving piston to minimise piston side-thrust.

Each end of the driving piston is reduced in diameter to a boss which has an outer flange An elastic U Cup O, seal (20) is placed on each boss and retained there by 2 the flange.

An inset elastic O-ring buffer (22) protrudes from a centrally-placed socket in each end of the driving piston.

These buffers provide cushioning and rebound in the stopping and restarting respectively of the piston at the end of one stroke and the beginning of the return stroke.

The front end of the driving fork is shown in figures 1 and 2.

The load-equalising yokes pivot in the bearing sockets and engage with the shearing cutter The comb is attached to the comb-plate (11) by the screws (12).

The tension pin (77) seats in the socket (76).

f 8 THE OPERATING VALVE SYSTEM The iiitegrated assembly of moving valve and valve-operating parts called the "valve movement", and the fixed parts, the valve-seat bodies (33) are shown in twice the actual size in figure 4. The left-hand parts and the central bearing sleeve are shown as they would be positioned within the motor housing. The right-hand parts are shown separated.

The valve movement consists of a pair of air escape valves each with a valve seal (42) retained on its valve stem (43) by the flange (42F) and with an end flange (44); a pair of air inlet valves (39) each of which is incorpo- 9 rated with a valve-operating piston (35) which has a U Cup seal (37) retained on the piston boss (36) by the washer a central bearing sleeve a mounting shaft (47), an elastic spring washer (49) and a securing pin (51).

Referring now to figures 3 and 5, after the valve and valve f operating parts are installed in their housing chambers in order of fit, the bearing sleeve in the bearing passage the valve operating pistons in the inner chambers (15C), the fixed valve-seat bodies in the outer chambers and the mounting shaft with the spring washer against the head (48) inserted through them all, they are clamped together and secured by the pin (51) which is retained in place by the end flange on the left hand air escape valve.

The end flange on the opposing air escape valve limits the outward expansion of the elastic spring washer.

The elastic valve seals are necessary because two valves -9are closed simultaneously with each reversal of the valve movement.

When installed the valve assembly forms three opposing pairs of chambers. The air Pece lalre 1 chambers (34) and the air inlet valve chambers (34B) are open to each other when their adjacent air inlet valves are open. The innermost pair of chambers (52) are called the "trip" chambers because each one, by being briefly pressurised at a determined time by the driving piston (18) from the adjacent driving chamber will de-activate its adjacent valve-operating piston which has been holding the closed valves against their seats and thereby release or "trip" the valve movement and allow it to reverse the attitudes of all the valves.

This action is brought about at the required time by Sconnecting each trip chamber to the driving cylinder by a "trip" passage which will be passed over by the adjacent driving piston seal and thereby be exposed to the pressure within the driving chamber, at a point which will leave t"I time for the driving piston to complete its stroke just "2"O as the driving chamber is becoming depressurised by way of the thus-opened adjacent air escape valve.

The valve system and the driving chambers are enclosed at each end by the side-plates (58) and their gaskets (58G) which are clamped in place by the bolts (61B) inserted within the bolt holes Before describing the operation of the motor in more detail it is convenient to describe the air passages, the control mechanism and the cutting tension device.

THE AIR PASSAGES AND THE CONTROL MECHANISM A longitudinal passage is made through the motor housing from the rear to the front and towards the left hand side (figure The rear end of the passage is enlarged in j diameter in two steps to provide two chambers. The larger and outer chamber is threaded to receive a connection (28) for a flexible air tube. The inner chamber (23) is the air-supply valve chamber. The air-supply valve (24) is inserted from the rear and its elastic valve seal (27) seats on the valve chamber step. A valve return-spring (25) is housed within the air-line connection (28) and bears against the valve head. The valve stem is housed 4 9 within the narrow section of passage and its end protrudes beyond the front of the motor housing where it is reduced 4# in diameter and rounded at the end. A control lever (29) (figure 2 section AA) is hinged to the front of the motor .n housing and has a section of inclined "ramp" (30) which bears against the end of the valve stem as the lever is depressed and so forces the valve stem backwards to open the valve and admit air pressure to start the motor.

The lever is extended horizontally over the handpiece in the form of a broad plate, which is shaped as a comfortable rest for the heel of the hand. The lever has a shallow recess (298) as an end stop in its inclined ramp into which the end of the valve-stem fits when the valve is £fuly open, thereby holding the valve in the open position and relieving the hand, until it is closed by manual upward pressure. A short grub-screw is inserted into the reas of the handpiece under the plate and to the right of the S-11 tension air passage. Screwing this scew outwards will provide an earlier end-stop, thereby preventing the end of the valve stem from reaching the recess and allowing the air-escape valve to re-close automatically when the lever is released. This adjustment should be useful for operations of short duration such as crutching or trimming.

Two transverse air galleries extend through the motor housing from side to side, these are the air pressure gallery (31) shown in figure 5 and the air escape gallery (32) shown in figures 1, 2 and 3.

i p S The air pressure gallery is placed immediately above the valve system and intersects the air supply valve chamber (23).

as The rectangular air inlet passages (54) lead downwards to the air inlet valve chambers (34B) as shown in figures t 1 and 3.

The passage (72) connects with the air passage (73) which, in turn, connects with the cuttlng tension pressure chamber which will be described later.

Referring now to figure 3, when each air i~ilet valve (39) opens, its valve chamber (34B) connects with the air-ee mk chamber Between each air escape valve chamber (34) and its adjacent driving chamber (17) is a "two ws'* air route which allows air to pass to and fr between the two chambers. This route is via a 4~ 1 (56) through the wall of each valve set 11 meets with a redess (57) in the motor h~ in turn, 'FS c y y Q~f A/ S- 12 is Opposite a cavity (59) in each side-plate The forward end of each cavity (59) faces into the adjacent driving chamber (17).

When each air-escape valve (41) opens, the air escape route is via the outer recess in each valve seat body (33) which faces into a second side-plate cavity This cavity extends downward and forward to face into the air escape gallery (32) which is alo a passage for a clamping bolt,.

The decompressing air leaves the air escape gallery by 1 0 way of two or three centrally-placed ports passing through the space surrounding the driving piston between its end seals, and through the driving slot above and below the driving shoe and thereon through the handpiece, over the cutter and comb to atmosphere, cooling and lubricating all moving parts as it passes them.

THE CUTTING TENSQTON DEVIrC 0 4 The cutting tension devace which applies pressure to the driving fork and thereby tensions the shearing cutter (9) is shown in figure 2. A cylindrical housing socket (78) 6 V' incorporated with the front of the handpiece 1z inwardly .the handpiec ia inwardly threaded to engage with an outwardly threaded tension housing The tension housing contains a tension piston with a guide-post (68) which fit and operate within a pressure chamber and a piston guide (69) rspectively. The tension piston is fitted with a U Cup s6al (66) which retained in position on the piston by the ilange The piston guide-post is hollow and contains a tension pin socket (75) which is inserted into -t i -13 its upper end. The outer end of the piston guide-post is reduced in diameter to a short spigot on which is mounted a weak cutter-holding spring which serves only to hold the driving yokes in engagement with the shearing cutter when the machine is not operating.

The pressure chamber (64) is pressurised by way of the air passage (72) figure 5, leading from the ai: pressure gallery (31) to connect with passage Passage (73) extends forward within the top of the handpiece body and into the tension housing socket where it meets a short Svertical passage (74) which emerges at the top of the housing socket. An angular passage (71) within the tension S housing leads from the pressure chamber and emerges from the step in the housing at a point which is opposite the vertical passage (74) when the tension housing is screwed firmly in position in the housing socket. An 0 ring seal (79) retained in a recess (79B) prevents air leakage at the junction of passages (71) and (74).

Figure 7 shows the tensioning device with the parts separated. Starting the machine immediately pressurises the o;amber (64) and causes the tension piston (65) to apply the required degree of tension to the shearing cutter by way of the tension pin the driving fork and the load-equalizing yokes When the machine is not operating the driving fork may be lifted manually against the light pressure of the cutter-holding spring (70) to remove and replace shearing cutters and combs.

i i THE MACHINE IN OPERATION 14 9: 9r 9 4:L 9 t f' Os.R pic In figure 3 the driving piston has completed its stroke to the left, exposing trip passage (53,R) and thereby equalising the pressure within trip chamber (53,R) with the pressures within the adjacent driving chamber (17), the air a scape -Lu echamber (34) and the air inlet valve chamber (34B). The pressures within the corresponding left hand chambers were also equal but low, having access to the air escape passages by way of the then open air oscape IYalve and the left-hand trip passage. The valve movement was then in the tripping situation wherein it had been moved to the right by the pressures behind the left-hand air inlet valve (39) and the right-hand air escape valve (41) as shown in figure 3. As all the valve attitudes have been reversed, pressure is now escaping from the four right-hand chambers via air escape valve whilst the left-hand driving, air escape and air inlet valve chambers are becr-Eing pressurised via air inlet valve (39,L) and the driving piston is about to be driven to the right.

The sealed area enclosed by the seal of a valve-operating piston is sufficiently greater than the combined sealed areas enclosed by an air inlet valve and an air escape valve seal to provide an adequate "holding" pressure to keep the closed valves airtight until they are re-opened.

The valve movement as shown in figure 3 will therefore remain in that position until the driving piston has moved to the right ad uncovered trip passage thereby pressurising t~ip chamber and deactivating valve-operating piston ,35,L) which will trip the valve w«* movement and allow it to be moved to the left.

Starting the motor therefore immediately applies cutting tension to the shearing cutter and simultaneously pressurises whichever driving chamber is adjacent to an open air inlet valve, thereby causing the driving piston to move and to interact with the valve movement to continue moving each other to and fro in alternate sequence within the motor housing and thereby to move the shearing cutter to and fro across the shearing comb.

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Claims (2)

1. A pneumatic operated shearing handpiece having a drive arm supported in a housing for pivotal movement about a pivot axis intermediate the length thereof, said drive arm being adapted to support a cutter element at one end to oscillate about said pivot axis, a cylinder mounted in the housing with the axis thereof extending transverse to the direction of length of the drive arm, a double ended piston within the cylinder mounted to reciprocate therein between respective closed ends of the cylinder, said piston having a recess in the periphery thereof with the other end of the drive arm extending through the cylinder and seated in said recess whereby the drive arm affects said oscillation of the cutter element in response to the reciprocating of the Vt pistgn, respective drive chambers being formed between the closed ends of the cylinder and the respective ends of the piston, and valve means to control selective supply of b* compressed air to an exhaust from said chambers to effect a t said reciprocation of the piston, said valve means comprising a pair of mirror image valve chambers arranged "co-axial to a common actuating rod extending into each valve chamber and axially slidably supported 'in a wall sealably separating said valve chambers, each valve chamber being associated with a respective one of the drive chambers, said actuator rod having mounted thereon in each valve chamber II two valve elements in a fixed axial spacing each adapted to Sindependently selectively sealably close respective ends of cr", ian air transfer chamber in continuous communication with a ,«respective drive chamber of the cylinder adjacent the closed end thereof, a compressed air supply port and an air exhaust port in each valve chamber arranged so the air exhaust port is isolated from the transfer chamber and the air supply port is in communication with the transfer chamber when the actuation rod is in one axial position relative to the wall and vice versa in an opposite position of the actuator rod, and so the arrangement in the respective valve chambers is i E4^ t Disk 0063/1.41 imass-l m i r -i~4 -17- the reverse for each axial position of the actuator rod, and an actuator piston fixedly mounted on the actuator rod in each valve chamber and sealably slidable therein, the respective valve chambers on one side of the actuator piston communicating with the air supply port and on the other side with a vent passage, the vent passage being selectively communicated with atmosphere and the drive chamber associated with that valve chamber at the respective ends of the movement of the piston in the cylinder.

2. A pneumatic shearing handpiece substantially as hereinbefore described with reference to the accompanying drawings. DATED this 16th day of November, 1989. .4 4 *e 9 S4 9* ROBERT ARTHUR ROSE 41 4* WATERMARK PATENT ATTORNEYS SUITE 18, 159 ADELAIDE TERRACE, EAST PERTH, W.A. 6004. r rces;t r r t h CZefTt G bisk 0063/1.41 1 1.,