AU644433B2 - A rotary actuator - Google Patents

Description

S4443 COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952 Form COMPLETE SPECIFICATION

(ORIGINAL)

FOR OFFICE USE Short Title: Int Cl: Application Number: Lodged: Complete Specification-Lodged: Accepted: Lapsed: Published: Priority: Related Art: TO BE COMPLETED BY PPLICANT Name of Applicant: KABUSHIKI KAISHA ISEKIKAIHATSU KOKI Address of Applicant: 31-6, 4-chome, Yoyogi Shibuya-ku, Tokyo, Japan Actual Inventor: TOSHIO AKESAKA and TAKASHI OGAWARA Address for Service: GRIFFITH HACK CO 71 YORK STREET SYDNEY NSW 2000 Complete Specification for the invention entitled: A RJTARY ACTUATOR The following statement is a full description of this invention, including the best method of performing it known to me/us:- GH&CO REF: 21034-C DJH/KLS 5235A/KLS/24.04.91 2 The present invention is a divisional application of AU 54849/90 which relates to a processing apparatus for performing operations which include cleaning, grinding, cutting or the like to an inner cylindrical surface of piping such as, for example, underground water pipe, gas pipe or wire pipe. Other applications of the processing apparatus include performing work to an inner surface of a tunnel, an inner cylindrical surface of steel pipe or a cylindrical face formed in a steel ingot or the like.

Specifically, the present invention relates to a driving apparatus which may be used in the cutting-controlling mechanism of the processing apparatus disclosed in AU 54849/90.

Concrete, steel and earthen pipes having various diameters are laid underground for use as water, gas pipe or wire pipes. Steel pipe piles and steel pipe-sheet piles, for example, are used in civil engineering works.

Periodically, it is necessary to carry out maintenance, repairs or improvements to the abovementioned various pipes. Various pipe interior working machines are available for performing the required operations to the inner surfaces of the pipes.

An example of work which may be carried out within a sewage pipe, for example, includes removing roots of trees which have penetrated into the sewage pipe through a joint in the pipeline. Other work which may be necessary includes removing earth, sand or rust attached to the inner wall of the pipeline. An example, of work which may be carried out to a steel pipe includes cutting work on those occasions where sections of the pipe are to be removed.

Recently, a method for repairing a portion of pipe, such as a sewerage pipe which is corroded or partially damaged, has been developgd.

In this method grooves are formed in the axial direction at both sides of the portion to be repaired and a plastic lining is inserted in the pipeline to effect S repair.

1034-C/1 5.01.93 -3- It is common that machines available to perform the work as mentioned above are known as so-called single capacity machines in which the respective functions are fixed, and the tools including wire brush, milling cutter or end mrill are moved in the radial direction of the pipeline by an oil pressure cylinder and the like to perform the work. Furthermore, it is common that the said machines are constituted so as to rotate in the circumferential direction by regarding an axial center of the working machine as a center.

For example, in the case where grooves are processed in the inner wall of a pipe by a milling tool when partially repairing a pipeline, it is necessary that the milling tool is moved in the radial direction in accordance with the inside diameter of pipe and the depth of groove to be processed. However, it is difficult to stop an oil pressure cylinder drive rod in the middle of a stroke to thereby accurately control the supply of oil to the oil pressure cylinder. Consequently, it is difficult to control the depth of the processed groove accurately thereby causing uncertainty during the execution of the work.

It has, therefore, been desirable to develop an apparatus for performing work to an interior surface of a S 25 pipe line which has several functions and can accurately control the movement of a tool to satisfactorily perform the required work to the interior surface.

An aim of AU 54849/90 is to provide a processing apparatus with which plural works can be performed to an inner cylindrical surface of a workpiece.

Accordingly, AU 54849/90 discloses a processing apparatus having a first axis and comprising; a working head having a working member for performing work to a work piece with an inner cylindrical surface; a driving mechanism for rotating the working head; and a controlling mechanism connected to the driving mechanism controlling the rotation of the working head; 34-C/1 5.01.93 4 wherein the working member is shifted from an initial position remote from the inner cylindrical surface to a working position in contact with the inner cylindrical surface by the working head when the work is to be performed and is circumferentially moved around the inner cylindrical surface by the rotation of the working head when performing the work to the work piece.

The aim of the present invention is to provide a rotary actuator which in a preferred embodiment can be used in the controlling mechanism for the above mentioned processing apparatus.

In a first aspect of the present invention there is provided a rotary actuator comprising: a casing defining a cylinder having a first axis; a piston dividing the cylinder into first and second chambers and being arranged to be rectilinearly moved within the cylinder; a driving shaft having a male first threaded portion engaging with a female second threaded portion on a first surface of the piston; and So a guiding means which can be secured to the casing and which has a first guiding portion engaging with a second guiding portion on a second surface of the piston; wherein the guiding means can be rotated to cause the piston to be rotated through the engagement of the first and second guiding portions and to travel along the driving shaft through the engagement of the first and the V second threaded portions, the rotation of the guiding means further causing the driving shaft to be rotated when the travel of the piston along the dr. ing shaft is halted through contact with a stop portion, and wherein the piston is prevented from rotating by the guiding means when the guiding means is secured to the casing and the engagement of the first and second threaded portions cause the driving shaft to be rotated when the piston is driven in the cylinder by fluid supplied under pressure to the first or the second chamber.

pfigure 4; Figure 6 is a sectional view of a rotary actuator embodied by the present invention; and Figure 7 is an end view of the embodiment of figure 6.

Detailed Description of the Preferred Embodiment In figure i, and inside processing apparatus is shown as an apparatus for cutting a groove in a fixed position of the inside of pipeline 60 made of concrete.

Bracket 11 on truck 10, is provided with a plurality of outriggers 80. Each outrigger 80 comprises an oil pressure cylinder. Preferably, three outriggers 80 are arranged 120 degrees apart on the outer circumference of the bracket 11. Outriggers 80 are operated by simultaneously supplying oil under pressure to each one to secure the apparatus centrally in pipeline Truck 10 may be drawn through pipeline 60 by cables or 70b. However, truck 10 may be self-pr'opelled by providing an apparatus with wheels connected to a drive motor.

An embodiment of the processing apparatus will now be described with reference to figures 2 to Driving mechanism 30, comprises: a case body 31 inserted within bracket 11 of truck 10 and a motor 32 for a driving source. The motor may be an oil pressure motor or an induction motor, for example, and is secured at the rear end of case body 31. The driving mechanism further comprises shaft 33, which is rotatably installed in case body 31 and is driven by motor 32. The shaft 33 has an axis which is coaxial with an axial center of the apparatus. Driving mechanism 30 further has a differential gear mechanism 34 disposed within an expanding diameter portign 31a formed towards the rear end of case body 31.

Shaft 33, and an output axle 32a of motor 32 are connected through sleeve coupling 35. A gear portion 33a is formed on the rear end of shaft 33. Gear portion 33a

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h P 34-C/ 15.01.0.

IPF~-~ Cg C~I IL_ l 6 is a solar gear comprising part of differential gear mechanism 34. Working head 20 is arranged at the opposite end of shaft 33.

Differential gear mechanism 34 comprises two planet gear mechanisms. The first planet gear mechanism comprises: an inner teeth gear 34a which is secured in the expanding diameter portion 31a; a first planet gear 34b which engages with solar gear 33a and also inner teeth gear 34a; and an outside sleeve 34c which connects with an axle 34c' on which first planet gear 34b is rotatably mounted. The second planet gear mechanism comprises: an inner teeth gear 34d, which is disposed rotatably within expanding diameter portion 31a; a second planet gear 34e which engages both inner teeth gear 34d and solar gear 33a; and an inside sleeve 34f which connects with axle 34f' on which second planet gear 34e is rotatably mounted. Inner teeth gears 34a and 34d are of the same module and have the same number of teeth.

Planet gears 34b and 34e also have the same module and also have the same number of teeth. Additionally, a gear engages inner teeth gear 34d anc6 is attached to driving axle 44 of the driving means of cutting controlling mechanism Outside sleeve 34c has an axis which is coaxial with the axis of shaft 33 and is rotatably supported in case body 31 through bearing 36. Inside sleeve 34f is arranged between outside sleeve 34c and shaft 33, and is rotatably supported by bearing 37 which is installed on shaft 33. Outside sleeve 34c is, therefore, held within case body 31 through bearing 36, inside sleeve 34f is held within outside sleeve 34c through bearing 37, and shaft 33 is inse-ted within inside sleeve 34f. Sleeves 34c, 34f and shaft 33 are arranged so as to be able to rotate independently of each other.

Working head 20 comprises a case 21 and gear mechanism 22 which is installed within case 21. Case 21 houses a circular cam 21b and is constituted by a head AqALIA1 cover 21a. Circular cam 21b is firmly mounted on outside 4-C/1 5.01.93

I--

7 sleeve 34c of the first planet gear mechanism. Arm 27 is mounted on inside sleeve 34f and extends past circular cam 21b to the inside of head cover 21a which is connected with the second planet gear mechanism through a link mechanism comprising arm 27 and a link plate 28.

Bearing portion 21a' is formed in a fixed position in head cover 21a and supports axle 24 to whic. working member 20a is mounted.

Circular cam 21b has an axis 21b' which is not coaxial with the axis of shaft 33 and is rotated around the axis of shaft 33 by the rotation of outside sleeve 34c.

Gear mechanism 22, comprises: a gear 23 installed firmly on the front end of shaft 33, gear 25 which is installed firmly on axle 24 and middle gear 26 which engages gears 23 and 25. When shaft 33 is driven, axle 24 is rotated by gear mechanism 22 resulting in the rotation of working member Middle gear 26 is rotatably mounted to axle 26a.

Arm 27 is also rotatably mounted to axle 26a and is firmly mounted to the front end of inside sleeve 34f of the second planet gear mechanism. Link plate 28 is further rotatably mounted to axle 26a and is also rotatably mounted on the bearing portion 21a'. The movement of arm 27 is limited by stopper 29 which is firmly mounted on circular cam 21b.

Cutting controlling mechanism 40 is fixed to a base 31b which is arranged on the rear end of case body 31.

It is possible to control the rotation of driving axis 44 by using, for example, an oil pressure motor, an induction motor or the like in combination with speed control means.

The present invention provides a rotary actuator which may be used as the driving means in cutting controlling mechanism 40. A preferred embodiment of the present invention will now be described with reference to figures 6 and 7.

Casing 41 of the rotary actuator encloses piston 42 which moves linearly in forward and backward directions )iO34-C/15.01.93 Lu_ -L

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8 and can rotate about an axis defined by the linear movement, a moveable member 43 which may rotate and move piston 42, a driving axle 44 rotatable by piston 42, a bearing member 46 rotatably supporting driving axle 44, and a regulating member 47 inserted in moveable member 43 which regulates the stroke limit of piston 42.

Ports 41a and 41b supply or exhaust oil under pressure to or from casing 41. Slit 41c is formed in the rear end of casing 41 and contracting members 41d and 41e are arranged on both sides of slit 41c. Moveable member 43 is held within casing 41 by constricting slit 41c by means of bolt 41f which is inserted through contacting member 41e and screwed into contracting member 41d. That is, the width of slit 41c is reduced when bolt 41f is tightened thereby fixing moveable member 43 in casing 41.

Accordingly, moveable member 43 may be released by loosening bolt 41f.

Piston 42 is formed in a cup-shape having a flange 42a. A spline 42b is formed on the outer circumference of piston 42 and a screw portion 42c having a fixed pitch is formed on the inner circumference.

A hole 43a in the center of moveable member 43 is provided for inserting regulating member 47 and a spline 43b is formed on the front end of moveable member 43 for engagement with spline 42b formed on piston 42.

Chamfered portion 43c having a nut-shape is formed on the outer circumference of the rear end of moveable member 43 and a screw portion 43d is formed on the inner circumference of chamfered portion 43c.

Gear 45 engaging inner teeth gear 34d is attached to the front end 44a of driving axle 44 which has projection 44b having a flange shape. Projection 44b formed in a fixed position around driving axle 44.

Movement of driving axle 44 is restricted by bearing member 46 and a cap 41e that is attached to the front end of casing 41. Driving axle 44 rotates in the axial direction and has a screw portion 44c which is engagable A) with screw portion 42c.

21034-C/15.01.93 1 9 A screw portion 47a for engagement with screw portion 43d is formed in the rear end of regulating member 47. Chamfered portion 47b is forrr,.d at the rear end of screw portion 47a. A lock nut 47c is screwed on screw portion 47a for locking regulating member 47 in position within moveable member 43.

Moveable member 43 may be rotated and moved after loosening bolt 41f, and rotating chamfered portion 43c with the aid of a spanner. The rotational movement is transmitted to piston 42 through splines 42b and 43b and subsequently piston 42 may be moved in forward or reverse directions. The movement of the piston in the forward direction is limited by bearing member 46 and in the reverse direction by moveable member 43. The rotation of piston 42 by moveable member 43 is transmitted to driving axle 44 through screw portions 42c and 44c when the piston contacts bearing member 46 or an end face of moveable member 43. Therefore, it is possible driving axle 44 may rotate through a desired angle by rotating moveable member 43. That is, it is possible to set the desired rotational movement of driving axle 44 by fixing moveable member 43 within casing 41 at a desired position. As a consequence of the rotational movement of driving axle 44, gear 45 which is attached to driving axle 44 rotates and inner teeth gear 34d is rotated.

Therefore, gear 45 may be rotated freely in keeping with the rotational movement of the moveable member 43.

SAn initial position of working member 20a may be achieved with respect to the inner wall of pipe line through the rotation of moveable member 43.

The supply of oil pressure to port 41b, when moveable member 43 is fixed within casing 41 by constricting contracting members 41d and 41e, results in piston 42 moving in the--forward direction (to the right of the drawing) in accordance with restriction supplied by splines 42b and 43b. The linear movement of piston 42 5.01.93 ;~3~IYIll~--~1 9a is converted into rotational movement of driving axle 44 by screw portions 42c and 44c. The rotational movement of driving axis 44 is regulated by the stroke of piston 73 56l.93 10 42 and is facilitated by screw; portions 42c and 44c while the stroke of piston 42 is regulated by regulating member 47 which is inserted in moveable member 43.

When piston 42 reaches bearing member 46 oil under pressure is supplied to port 41a and piston 42 moves in the reverse direction. As moveable member 43 is fixed in casing 41, piston 42 moves linearly in accordance with the restriction of splines 43b and 42b and driving axle 44 is rotated in the opposite direction.

Regulating member 47 may be rotated and moved by loosening lock nut 47c and by engaging a spanner with chamfered portion 47b. Hence, regulating member 47 may be moved in the axial direction by rotating screw portion 47a with respect to 43d and the stroke of piston 42 can be regulated by adjusting the length of regulating member 47 projecting from moveable member 43. When the stroke of piston 42 is regulated as mentioned above limited rotation of gear 45 is established, consequently causing limited movement in the radial direction of working member The operation of working head 20, driving mechanism and cutting controlling mechanism 40 of the processing apparatus will now be described.

Before the apparatus is inserted in the pipeline a working member 20a which is suitable for the work required is mounted on working head 20. The initial position of working member 20a is then established with regard to the inner wall of pipeline This iz achieved by rotating moveable member 43 in cutting controlling mechanism 40, when motor 32 is stopped, resulting in rotational movement of inner teeth gear 34d and the second planet gear mechanism.

Arm 27 rotates in the direction of arrow B (Fig 4) by means of the rotational movement of the secoiLid planet gear mechanism. An intersecting angle between arm 27 and link plate 28 changes as a result of the rotating movement of the arm 27 and head cover 21a is moved in the direction of arrow B regarding the centre 21b' of -11circular cam 21b as a center when arm 27 engages with stopper 29 on circular cam 21b. The end result is working member 20a moving in the radial direction of pipeline 60. The initial position of working member is established so that the distance between the outer circumference of the working member 20a and the inner wall of the pipeline 60 is fixed.

The required cutting depth of working member 20a is set with regard to the initial position of working member 20a by setting the stroke of piston 42 in cutting controlling mechanism 40. Therefore, moveable member 43 is fixed in casing 41 and regulating merr2 47 is rotated and positioned to regulate the strcke of piston 42.

Hence, it is possible to process a groove having a fixed depth in pipeline 60 by setting the stroke of piston 42.

After the initial position and the cutting depth of working member 20 are established, the working apparatus is inserted in pipeline 60 and is positioned by wires and 70b. Operating the outriggers 80 caujes the axial cen-er of the working apparatus to coincide with the axial center of pipeline 60 and fixes the working apparatus in pipeline Next, motor 32 is operazed and the driving force of motor 32 is transmitted in accordance with the schematic diagram as shown in figure 3. Motor 32 thereby rotates solar gear 33a and wor,ing member 20a. The first and second planet gear mechanisms are rotated at the same velocity and circular cam 21b, which is part of the first planet gear mechanism, and arm 27, which is part of the second planet gear mechanism, are also rotated, at the same velocity about shaft 33. The working member rotates in a state in which the distance from the inner surface of pipeline 60 is maintained.

When oil under pressure is supplied to ports 41a or 41b piston 42 moves in the forward or backward directions. Gear 45 rotates in association with the movement of piston 42 and subsequently, inner teeth gear iA, 34d is rotated. The rotation of inner teeth gear 34d 5.01.93 12 provides a relative rotational velocity difference between the first planet gear mechanism and the second planet gear mechanism, resulting in a change in the intersecting angle between arm 27 and link plate 28, and a change in the position of working member 20a in relation to the inner wall of pipeline 60. The distance between working member 20a and shaft 33 varies as working member 20a is shifted to a working position with the movement of head cover 21a.

Figure 5 illustrates the operation of working head when a relative rotational velocity difference has been established between the first and second planet gear mechanisms. In figure 5, a solid line indicates a time instant in which the initial position of working member 20a has been established and piston 42 is in a particular position. A chain line indicates a time instant in which the working member 20a has moved into the working position following movement of piston 42.

Following the fixed cutting movement as described above on the inner wall of pipeline 60 by vorking member supply of oil under pressure to the cutting controlling mechanism is intercepted. Gear 45 is locked by driving axis 44 and inner teeth gear 34d is thereby also prevented from rotating. Consequently, the first planet gear mechanism and the second planet gear mechanism rotate at the same velocity and a groove is processed as the working member is moved circumferentially around the inner wall of pipeline 60 by working head After working member 20a makes one revolution around the inner wall of pipeline 60 and the groove is processed, oil pressure is supplied to the other of ports 41b or 41a while solar gear 33a is rotating or stopped.

Piston 42 moves the oppoqte direction within casing 41.

In keeping with this movement, gear 45 rotates in an opposite direction resulting in the reverse rotation of inner teeth gear 34d. The rotation of the inner teeth gear 34d is transmitted to the head cover 21a causing 13 working member 20a to be shunted to the initial position.

Subsequently, outriggers 80 are shunted, the working apparatus is released from its position within pipeline Thereafter, it is possible that further work in pipeline 60 can be performed by pulling the working apparatus to a new fixed working position by means of the wires 70a and 70b and repeating the same operation as above.

While a processing apparatus has been described using a milling cutter as working member 20a, alternative forms of working members may be used to achieve different functions. For example a rolling cutter to cut a groove in the pipeline, a cutting tool to remove a tree root which has penetrated the pipeline or a wire brush or grinder to clean the inside of the pipeline may be used.

The working member 20a is rotated by transmitting the driving force of the motor 32 to the axis 24 through the shaft 33 and the gear mechanism 22. However, rotation of the working member may be provided by a dedicated motor connected to axle 24.

The processing apparatus is not limited to performing work on pipes but can be applied to other cylindrical inner surfaces which require work such as grinding, cleaning or cutting to be carried out. Items to which such work may be applicable include, for example oil pressure cylinders, air cylinders and engine blocks.

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Claims (10)

1. A rotary actuator comprising: a casing defining a cylinder having a first axis; a piston dividing the cylinder into first and second chambers and being arranged to be rectilinearly moved within the cylinder; a driving shaft having a male first threaded portion engaging with a female second threaded portion on a first surface of the piston; and a guiding means which can be secured to the casing and which has a first guiding portion engaging with a second guiding portion on a second surface of the piston; wherein the guiding means can be rotated to cause the piston to be rotated through the engagement of the first and second guiding portions and to travel along the driving shaft through the engagement of the first and the second threaded portions, the rotation of the guiding means further causing the driving shaft to be rotated when the travel of the piston along the driving shaft is halted through contact with a stop portion, and wherein the piston is prevented from rotating by the guiding means when the guiding means is secured to the casing and the engagement of the first and second threaded portions cause the driving shaft to be rotated when the piston is driven in the cylihder by fluid supplied under pressure to the first or the second chamber.

2. A rotary actuator according to claim 1 wherein the first and second guiding portions are splines.

3. A rotary actuator according to claim 1 or 2 wherein the the stop portion is a bearing means which rotatably supports the driving shaft.

4. A rotary actuator according to claim 1 or 2 wherein the stop portion is an end face of the guiding means. 15 A rotary actuator according to any one of claims 1 to 4 wherein the guiding means can be secured to the casing by a securing means.

6. A rotary actuator according to claim 5, wherein the securing means comprises a first and a second clamping portion located on an exterior portion of the casing and which are separated by a slit in the casing, and wherein the guiding means is secured to the casing by clamping the first and the second clamping portions together so as to constrict the slit.

7. A rotary actuator according to any one of the preceding claims wherein the rotary actuator further comprises a limit member for limiting movement of the piston between a first and a second end of the cylinder, and wherein the limit member is arranged so as to be able to adjust a stroke length of the piston.

8. A rotary actuator according to claim 7 wherein the limit member is arranged in a passageway in the guiding means and is moveable with respect to the guiding means so that a portion of the limit member may be caused to extend from the passageway to decrease the stroke length of the piston, and wherein the stroke length may be adjusted by varying the distance the portion of the limit member extends from the passageway.

9. A rotary actuator according to claim 8, wherein the passageway is a through passageway which has a longitudinal axis which is coaxial with the first axis of the cylinder and the limit member has a male third threaded portion engaged with a female fourth threaded portion on an inner surface of the passageway, and wherein the portion of the limit member may be caused to extend from the passageway by rotating the limit member with respect to the guiding means. 16 A rotary actuator according to any one of the preceding claims wherein the piston is cup-shaped.

11. A rotary actuator substantially as herein described with reference to figures 6 and 7 of the accompanying drawings. DATED this 30th day of September 1993 KABUSHIKI KAISHA ISEKIKAIHATSU KOKI By their Patent Attorneys GRIFFITH HACK CO

21034-C/05.10.93