GB1600926A

GB1600926A - Tube severing apparatus and a method of severing tubing

Info

Publication number: GB1600926A
Application number: GB1797978A
Authority: GB
Original assignee: BERTOLETTE MACHINES Inc
Current assignee: BERTOLETTE MACHINES Inc
Priority date: 1978-05-05
Filing date: 1978-05-05
Publication date: 1981-10-21

Description

(54) TUBE SEVERING APPARATUS AND A METHOD OF SEVERING TUBING (71) We, BERTOLETTE MACHINES, INC., a corporation of the State of Connecticut, United States of America, Post Office Box 507, 65 New Litchfield Street, Torrington, Connecticut 06790, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statements: This invention relates to tube severing apparatus and to a method of severing elongated tubing as well as to lengths of tubing severed thereby.

Tube severing apparatus employing a plurality of small rotary cutters have been extensively and quite successfully used in the past. An accurate, scrapless cut tends to be achieved and with proper cutter selection and control, ID reduction and internal burring may be reduced. There are, however, many applications where little or no ID reduction or burring is permissible. ID reductions in the order of several thousandths are usually encountered and even a few thousandths may be objectionable in certain applications.

An object of the present invention is to provide tube severing apparatus and a method of severing tubing wherein little or no ID reduction or burring is encountered.

According to the present invention there is provided tube severing apparatus comprising neans capable of axially advancing elongated tubing in a forward direction to present at a cutting station a leading end portion to be separated from the remainder of the tubing, intermittently operable clamping means adapted to engage the tubing rearwardly of the leading end portion to secure the tubing during cutting, a rotary cutting head at said cutting station having an aperture to receive the leading end portion, said head having at least one rotary cutter adjacent the aperture movable generally inwards and outwards in a direction transverse to the tubing and the aperture to engage and cut into the tubing and to withdraw from engagement therewith, means capable of rotating the cutting head and of moving the or each cutter inwards to perform a cutting operation, said last-mentioned means further enabling movement of the or each cutter outwards to permit advancement of the tubing between successive cutting operations, adjustable means capable of limiting inward movement of the or each cutter in accordance with tubing width and wall thickness to provide a generally uniform peripheral cut of controlled depth, and intermittently operable means capable of applying a generally transverse force to the leading end portion of the tubing to break off the leading end portion from the remainder of the tubing after a cutting operation has been performed.

Further according to the present invention there is provided a method of severing elongated tubing comprising the steps of: a) axially advancing tubing in a forward direction to present a leading end portion, to be separated from the remainder of the tubing, at a cutting station where the leading end portion is received in an aperture of a rotary cutting head having at least one rotary cutter; b) clamping the tubing rearwardly of the leading end portion; c) rotating said cutting head and moving the at least one rotary cutter inwards in a direction transversely of the tubing and the aperture to engage and cut into the tubing; d) limiting the depth of cut in accordance with tubing width and wall thickness to provide a generally uniform peripheral cut of controlled depth; e) applying a generally transverse force to the leading end portion to break off the leading end portion of the tubing; f) moving the at least one rotary cutter outwards in a direction transversely of the tubing and the aperture and thereby withdrawing the at least one cutter from engagement with the tubing before or after the step of applying said generally transverse force, and g) further axially advancing the remainder of the tubing in a forward direction to present a leading end portion of said remainder at the cutting station for successive cutting and break-off operations.

Still further according to the present invention there is provided a length of tubing in which at least one end has been severed according to a method as described in the immediately preceding paragraph.

By the present invention, a "cut and break" technique is employed wherein a partial cut is provided of precisely controlled depth in accordance with tube width and wall thickness.

Moreover, the cut should be of a high degree of uniformity and a subsequent break-off operation may result in ID reductions in the order of one or two thousandths or even in the complete elimination of ID reduction. The break-off operation is effected by a generally transverse force and yet there may be no collapse or flattening of the severed tubing end surface on an opposite side to that to which the force is applied by the break-off means, and in fact a uniform sharp generally axially facing edge may be provided throughout the tube circumference. Further, the sharp edge may reside at or radially outwardly of the tube ID and a curved surface may occur extending therefrom to the tube ID. In some applications this curved surface is highly desirable to facilitate the subsequent insertion of other tubing or cylindrical members into the open severed end of the tubing.

Preferably, the means capable of rotating the cutting head and moving the at least one cutter inwards and outwards comprises a mechanical driving mechanism which is capable of rotating the cutting head and a powered rod and cylinder cooperable with the mechanical driving mechanism to move the or each cutter inwards and outwards. The mechanical driving mechanism may comprise co-axial first and second pulleys adapted to rotate said head and move the or each cutter, and respective motion transmitting means connecting the second pulley with the or each cutter, said second pulley being angularly displaceable about its axis relative to said first pulley to actuate the respective motion transmitting means to move the respective cutter inwards or outwards upon actuation of said powered rod and cylinder. The tube severing apparatus conveniently has a driving mechanism further comprising a drive pulley connectable to a power source and first and second belts drivable thereby and respectively adapted to drive the first and second pulleys, the second belt extending around a spring-biased take-up pulley, and wherein displacement of the rod of the powered rod and cylinder is adapted to displace the belt, the take-up pulley being moved upon displacement of the belt, whereby the second pulley is angularly displaced with respect to the first pulley to move the or each cutter. Conveniently, the displacement of the rod is adapted to pivot a lever carrying a roller which engages the second belt whereby such pivotal movement effects displacement of the roller to displace the belt.

An embodiment of tube severing apparatus in accordance with the present invention will now be described by way of example only, with reference to the accompanying schematic drawings, in which: Figure 1 is a top view of the tube severing apparatus including a first form of break-off assembly; Figure 2 is a side view of the tube severing apparatus shown in Figure 1; Figure 3 is an exploded perspective view of a cutting head assembly of the tube severing apparatus; Figure 4 is a fragmentary sectional view taken generally along the line 4-4 in Figure 1; Figure 5 is a view showing a mechanical driving mechanism capable of rotating the cutting head assembly and adjustable limiting means for controlling the depth of cut effected by the cutting head assembly; Figure 6 is a top view of an alternative form of break-off assembly; Figure 7 is a longitudinal sectional view of an end of a tube portion severed by conventional prior art tube severing apparatus in a "through cut" operation, and Figure 8 is a longitudinal sectional view of an end of a tube portion which has been partially severed and broken off in accordance with the present invention.

Referring particularly to Figures 1 and 2, it will be observed that a Cutting Station A is provided in tube severing apparatus indicated generally at 10. The tube severing apparatus 10 has its principal operating elements mounted atop a table-like horizontally extending and generally rectangular frame member 12, drive means for the operating apparatus elements being conveniently disposed therebeneath.

An intermittently operable power feed means for the apparatus is indicated generally at 14 and serves to axially advance an elongated section of tubing such as 16 in a forward direction from left to right in Figures 1 and 2. The section of tubing at 16 is so advanced by the feed means as to successively present trailing end portions of leading end tube sections to the Cutting Station A. At the Cutting Station A, a cutting head assembly indicated generally at 18 operates to partially sever the leading end tube sections in succession as they are first advanced by the feed means and thereafter securely held by intermittently operable clamping means in the form of a fixed clamp assembly indicated generally at 20. The partially severed leading end sections are thereafter successively acted upon by a break-off assembly indicated generally at 22 and which applies a sharp generally radially directed force to effect a clean break at a partial cut 24.

The feed means 14 may vary widely within the scope of the invention, but as illustrated, a fluid operable cylinder 26 is preferably provided and is secured at a rear end position by means of a suitable bracket 28 mounted on the frame member 12. The bracket 28 also secures rear end portions of two identical longitudinally extending and laterally spaced guide rods 30. The bracket 28 may be fixed to the frame member 12 as by appropriate screws or bolts 32, and is provided with an integral upright support for the elongated tube 16. That is, an integral upstanding portion of the bracket may include an upwardly open V-shaped groove as at 33 for slidably supporting the section of tubing 16.

The fluid operable cylinder 26 preferably takes the form of a pneumatic cylinder and has a conventional rod 34 projecting therefrom and longitudinally toward the Cutting Station A. The rod 34 reciprocates in the usual manner and at its forward end portion is fixedly connected to a slide 36 mounted on the guide rods 30. The slide 36 is movable between the fixed clamp assembly 20 and a rear stop 38 also mounted on the guide rods 30. The rear stop 38 is secured to the guide rods 30 by means of suitable binder screws 40, and is adjustable therealong as may be required for the desired stroke of the rod 34. Thus, it will be apparent that the feed stroke and the length of tubing advanced during each stroke may be readily adjusted and controlled by conventional means such as limit switches and solenoid operated valves associated with the pneumatic cylinder 26.

A second means of support for the section of tubing is preferably provided at the stop 38 and may comprise an integral upstanding central portion having a V-groove 42 as illustrated.

The slide 36 forms a part of a feed clamp assembly operable in timed relationship with the pneumatic cylinder 26 to grip and release the tube 16 whereby successively to advance the same from left to right. As best illustrated in Figure 4, the slide 36 carries two upright members 44 which are spaced apart laterally and which support a fluid operable cylinder 46 thereabove. The fluid operable cylinder 46 is preferably of the pneumatic type and of a configuration commonly known as a "pancake cylinder". The pneumatic cylinder 46 operates to urge an upper clamping block 48 downwardly into engagement with the tubing 16 disposed between the said block and a fixed lower clamping block 50. Thus, the tube is securely clamped and held when the cylinder 46 is actuated and, on release of downward pressure by the cylinder 46 on the block 48, relative sliding movement between the tube and the clamping blocks is accommodated.

Small bosses or sleeves 52 on and about the guide rod 30 are formed integrally with or fixed to the slide 36 and project longitudinally therefrom. Four such bosses or sleeves are provided acting as two front and two rear stops. That is, the two forwardly facing bosses are engageable with the fixed clamp assembly 20 and the rearwardly facing bosses are engageable with the rear stop 38.

The fixed clamp assembly 20 comprises a bracket 54 which may be mounted on the frame member 12 as by means of appropriate screws or bolts 56 and which receives and supports forward end portions of the guide rods 30. The clamping assembly includes vertically stacked upper and lower clamping blocks and a pancake pneumatic cylinder 58. The clamping blocks, not shown, may be identical with the blocks 48,50 in Figure 4 and may be held in position by upstanding members 60 spaced laterally and supporting the cylinder 58.

As will be apparent conventional means may be employed for operating the cylinder 58 in timed relationship with the cylinder 26 and the feed clamp assembly. That is, the clamp assembly 20 is operative to secure the tube for a cutting operation when a forward stroke of the cylinder rod 34 has been completed positioning the tube for a partial severing operation by the cutting head assembly 18. During feed strokes, the pancake cylinder 58 is operated to release the tubing 16 for forward sliding movement through its associated clamping blocks.

The cutting head assembly 18 is best illustrated in Figures 1, 2 and 3 and comprises a rotary cutting head 62, first and second support members 64,66 mounted on the frame member 12, and first and second drive pulleys 68 and 70 of a mechanical driving mechanism. The cutting head 62 is centrally apertured as are all of the members 62, 64, 66, 68 and 70, best illustrated in Figure 3. Thus, a leading tube section may be introduced to the central apertures of the cutting head and the associated members from left to right in Figures 1 and 2 and a partial cut effected at a trailing end portion of such section by cutters mounted on the head.

In accordance with the invention, at least one small rotary cutter is provided on the cutting head 62 and, in the preferred form best illustrated in Figure 3, three such cutters are provided at 72, 74 and 76. The small rotary cutters 72, 74 and 76 are adapted to be moved generally radially inwardly and outwardly respectively to engage and partially sever a tube and to retract therefrom. One or more of the cutters may have a flat peripheral surface and serve merely as a roller or rotary back up member and it will apparent that various combinations of back-up rollers and cutters may be provided. Thus, one rotary cutter may be provided with two back-up rollers, two cutters with a single back-up roller and so on. As shown, each of the small rotary elements 72, 74 and 76 may be regarded as a cutting element.

Still referring to Figure 3, it will be observed that the cutters 72, 74 and 76 are restrained for linear movement along radial lines and are mounted respectively on slides 78, 80 and 82.

The slides 78, 80 and 82 are equally spaced circumaxially of the cutting head and each slide has a corresponding guideway; one being shown for the slide at 86. Gibs 88 secure the slides in their guideways in a conventional manner.

The cutting head 62 is driven by the first pulley 68 which is preferably of the cog type and which is positively secured to the head and mounted on a sleeve 90. The second pulley 70, also preferably of the cog type, is coaxial with the pulley 68 but is independently mounted for rotation with and relative to the pulley 68. The pulley 70 serves as an element in an actuating means for the slides 78, 80, 82 and the cutters 72, 74 and 76.

Actuation of the rotary cutters and their slides for inward and outward movement is achieved by effecting angular displacement of the pulley 70 relative to the pulley 68 while the said pulleys are rotating in the same direction and at the same speed, clockwise rotation being indicated in Figure 3 by the arrows 92, 94. Each of the three cutter slides is connected to a discrete motion transmitting means but for clarity of illustration a single motion transmitting means has been shown and will be described. The motion transmitting means shown drives the slide 82 and the cutter 76 and it will be understood that identical motion transmitting means are or may be employed for the slides 78, 80 and the cutters 72 and 74.

Internal gear teeth are provided in the pulley 70 and while it will be apparent that a complete 360C internal gear could be employed, it is preferred that three segments are provided at 96, 98 and 100. The segments respectively drive small planet gears of respective motion transmitting means, one shown at 102, for partial rotation of the latter on occurrence of an angular displacement of the pulley 70 relative to the pulley 68.

The motion transmitting means has a shaft 104 which carries a small eccentric pin 106 at a free end portion thereof. Axial opening 108 in the sleeve 90 receives the shaft 104 and restrains the shaft and its gear for partial rotation about its own axis. At a free end portion, the shaft 104 also projects through an opening 110 in the head 62 and the eccentric pin 106 thereon is pivotally received in a small opening 112 in a free and swingable link 114. The link 114 serves to convert arcuate movement of the pin 106 to linear radial movement as required for actuation of the slide 82. While it will be apparent that the link 114 might be connected directly to a pin on the slide 82, it is preferred that an intermediate adjustment member be included in the form of a small plug 116 which carries an integral cylindrical enlargement 118 at a rear end and which has a socket head opening 120 at an opposite or front end. An eccentric pin 122 on the cylindrical enlargement 118 enters and is free to rotate in a small opening 124 in the link 114, the said opening being disposed at an end of the link opposite the opening 112. The plug 116 is received in a suitable cylindrical through opening 126 in the slide 82 with its socket head 120 exposed for manual adjustment. A split rear or outer end portion of the slide indicated at 128 has an associated binder screw 130 for clamping and releasing the plug 116 in the opening 126.

It will be apparent from the foregoing that the plug 116 provides an important function in precise adjustment of the radial position of the slide 82 in a set-up operation. With the binder screw 130 slightly retracted, the plug 116 may be partially rotated by means of a suitable socket head tool inserted in the opening 120 whereby to establish a desired reference position for the slide 82 relative to a tube section to be cut. Slight arcuate movement of the pin 122 will displace the link 114 at the opening 124 within the guideway 86 to effect the desired linear adjustment of the slide 82 along its radial line of movement. A very precise adjustment is attainable as required for close depth control and circumferential uniformity of the partial cut operation of the tube severing apparatus.

As will be apparent, each of the slides 78, 80, 82 and their respective cutters or rollers are precisely adjusted to desired reference positions by means of plug 116 and identical plugs in the remaining slides. Precise set-up having been achieved, a high degree of accuracy and repeatability results in the partial cutting operation, the motion transmitting means for the slides and cutters being positive and mechanical in nature with no slippage or other unintended or accidental displacement of elements occurring.

Figure 5 shows the mechanical driving mechanism and best illustrates the manner in which the first and second pulleys 68 and 70 are driven as well as the means for achieving the necessary running angular displacement of the pulley 70 relative to the pulley 68. Pulley 70 is illustrated in Figure 5 and it will be understood that the pulley 68 is disposed directly therebehind in coaxial relationship and driven by a cog belt from common drive pulley 132.

The right hand and upwardly moving pass of the cog belt driving the pulley 68 is shown at 134. A left hand and downwardly moving pass of the cog belt lies directly behind a similar belt pass 136 which drives the pulley 70. A right hand and upwardly moving pass of the cog belt driving the pulley 70 is illustrated 138 and has an associated idler pulley 140 which is adapted for spring biased radial movement. That is, the pulley 140 is movable generally radially with respect to its axis through an arcuate path indicated by arrow 142. An arm 144 supports the pulley 140 for free rotation and a second idler pulley 146 is freely rotatable about a point 148, which point also forms a pivot axis for the arm 144. The arm 144 has an associated arm 150 fixed relative to the arm 144 and swingable therewith about the axis 148 in directions indicated by arrow 152. At an outer and free end portion 154 of the arm 150, a tension spring 156 is adapted to urge the arm in a clockwise direction thereby urging the idler pulley 140 in a clockwise direction, or generally toward the left in Figure 5. The right hand cog belt pass 138 for the pulley 70 extends upwardly from drive pulley 132 and has sufficient slack so as to be disposed partially about the pulley 140, and partially about the pulley 146 and then upwardly to the pulley 70.

The left hand or downward pass 136 of the cog belt driving the pulley 70 has an associated roller or pulley 158 disposed externally in engagement therewith and mounted for rotation at a free end portion of one arm 160 of a lever in the form of a generally L-shaped member having a second arm 162. The arm 160 is disposed generally vertically and the arm 162 generally horizontally with the L-shaped member pivotally mounted about an axis 164.

Arcuate movement of the L-shaped member as indicated by the arrow 166 may be effected by a powered rod and cylinder such as a fluid operable cylinder, for example pneumatic cylinder 168 having a rod or plunger 170 engageable with a free end portion of arm 162.

On operation of cylinder 168 urging its rod or plunger 170 upwardly in Figure 5, it will be apparent that the roller 158 will be swung in a clockwise direction urging the left hand or downward belt pass 136 rightwardly or inwardly as indicated by broken line 171. When such action occurs with the pulleys 68 and 70 being rotated simultaneously and at the same speed by the common drive pulley 132, the pulley 70 is angularly displaced (advanced) with respect to the pulley 68. The idler pulley 140 is swung in a generally counterclockwise direction against the urging of spring 156 and, on release of pressure by the roller 158, the belt passes 136, 138 return to the full line positions shown for continued rotation of the pulley 70 in unison with and at the same speed as the pulley 68. Further, it will be apparent that the temporary angular displacement or advance of the pulley 70 relative to the pulley 68 will result in a partial rotation of planet gear 102, Figure 3, and its counterparts and the cutters 72, 74, 76 will be urged inwardly in a partial tube cutting operation. Still further, it will be apparent that the extent of movement of the roller 158 will determine the precise amount or degree of inward movement of the cutters and their slides. The cog belts provide a positive drive and the extent of movement of the roller 158 can be closely controlled whereby to accurately control cutter movement and to determine precisely the depth and uniformity of the partial cut.

An adjustable means for limiting precisely the movement of the roller 158 and for thus precisely limiting depth of the partial cut is further provided. Said means may vary in form but preferably comprises a limit switch 172 which has its plunger 174 disposed in the path of movement of the arm 162 and which is adjustably mounted. The limit switch is adapted to control the operation of the cylinder 168 and such connection is illustrated by broken line 174. The manner in which the limit switch controls the operation of the cylinder 168 may be conventional and may include the provision of a solenoid operated valve controlled by the switch and operating the said cylinder.

The manner in which the adjustable mounting for the limit switch is provided may also vary but preferably includes an elongated lead screw 178 threadably entered in a suitable opening 180 in the frame member 12 and supporting the limit switch 172 at a lower end portion. A manually operable adjustment wheel or knob 182 at an upper end portion of the lead screw 178 is exposed atop the frame member 12, Figures 1 and 2, so as to be readily manipulated by a machine operator during set up. A cut and try method may be employed in adjusting the knob 182 for the desired depth of cut in the tube sections.

Reverting now to Figures 1 and 2, it will be observed that the break off means 22 is illustrated in the form of a powered piston and cylinder including a fluid operable cylinder 184 mounted on the frame member 12 by means of a bracket 186 and having its axis disposed generally radially with respect to the tubing 16. A cylinder piston 188 is arranged to engage a leading end section of the tubing 16 and to exert a sharp generally radially directed force in a break off operation. A quill 190 takes the form of a cylindrical member having an axial opening axially aligned with and adapted to slidably receive but securely hold the tubing. The quill 190 is supported on the frame member 12 by means of a bracket 192.

As will be apparent, the quill 190 securely holds a leading end position of a section of tubing having its trailing end portion positioned at the Cutting Station A. A preceding partial cut 24 is disposed forwardly of the quill 190 and preferably in closely spaced relationship therewith. Thus, the preceding leading end tube section extends forwardly from the quill and is engaged by the plunger 88 and cleanly broken off. Such action may occur simultaneously with a partial cutting operation on the next succeeding tube section at the Station A. It should also be noted that the cutting head assembly may be reversely oriented; that is, the assembly may be rotated through 1800, the quill eliminated and the break off means operated on a leading end section immediately following a partial cut at its trailing end portion. In such event, the cutters may be maintained in engagement with the tube during break off for clamping action or, alternatively, clamping means may be provided within the cutting head and operated automatically to secure the tube during break off.

In Figure 6 an alternative break-off assembly is illustrated. It should be understood that an associated tube severing apparatus may be provided which is identical in all respects with the apparatus illustrated in Figures 1-5 except that it includes the alternative break-off assembly. A quill 190a may be of appropriate length for the support of leading end tube sections somewhat longer than those accommodated in the machine of Figures 1-5. A support means is provided for the forwardly projecting leading end section of tubing 16a to be broken off at a partial cut 24a. The partial cut 24a is disposed forwardly of and in closely spaced relationship with the quill 190a. The support means takes the form of a cylinder 194 having an axial opening for receiving the tube as it is advanced by the feed means 14 after a partial cutting operation. The axial opening is of such dimension as to slidably receive and yet securely hold the tubing. At a rear end portion the cylinder 194 is supported for swinging movement generally about the partial cut 24a. That is, hinge members 196, 198 respectively secured to the quill and the cylinder are pivotally connected at 200 to provide for arcuate movement of the cylinder generally as indicated by arrow 202.

A fluid operable cylinder 184a, preferably in the form of a pneumatic cylinder, has a piston 188a pivotally connected to a small bracket 204 at 206. The bracket 204 is fixedly mounted on the cylinder 194 so that forward movement of the plunger 188a will operate to swing the cylindrical member 194 in a counter-clockwise direction as shown and, conversely, rearward or retractile movement of the plunger will return the cylinder in clockwise movement to the position shown, said position being in axial alignment with the quill 198 and the tubing 16a. The cylinder 184a is pivotally mounted as by means of a small bracket 208 at its rear end portion on a fixed bracket 210.

When the cylinder 194 has been pivoted by the cylinder 184a in a break-off operation and has been thereafter returned to a position of axial alignment, a further advance of the tubing 16a will obviously serve to eject the separated leading end tube section from the right hand end of the cylinder.

The significance of the "cut and break" technique of the present invention as compared with conventional "through cutting" is best appreciated with reference to Figures 7 and 8.

In Figure 7 an end section of tubing 16b is illustrated in a somewhat schematic manner and it will be observed that a substantial ID reduction has occurred in a conventional "through cut" operation. The dimension X represents ID reduction and it will be observed further that a relatively sharp inwardly directed annular edge 212 results from the "through

Conventional through-cut "Cut and break technique" Tube Diameter OD - 3/8" Same Material - Soft Copper Same Wall Thickness - .030 thousandths Same ID Reduction - .006 to .008 thousandths .001 thousandths In other tests with the improved tube cutting machine of the present invention, ID reductions as high as .015 (fifteen thousandths) have been reduced to the level of .001 or .002 (one or two thousandths) and even eliminated in the sense that they are so insignificant as to be beyond conventional gauging techniques.

The depth of the partial cut prior to break-off is dependent upon wall thickness, diameter of the tubing, type of material, etc. For best results, it is believed that the partial cut should be of a depth approximately 2/3 wall thickness or until a discernible ring or ridge appears in the tube ID opposite cutter engagement.

WHAT WE CLAIM IS: 1. Tube severing apparatus comprising means capable of axially advancing elongated tubing in a forward direction to present at a cutting station a leading end portion to be separated from the remainder of the tubing, intermittently operable clamping means adapted to engage the tubing rearwardly of the leading end portion to secure the tubing during cutting, a rotary cutting head at said cutting station having an aperture to receive the leading end portion, said head having at least one rotary cutter adjacent the aperture movable generally inwards and outwards in a direction transverse to the tubing and the aperture to engage and cut into the tubing and to withdraw from engagement therewith, means capable of rotating the cutting head and of moving the or each cutter inwards to perform a cutting operation, said last-mentioned means further enabling movement of the or each cutter outwards to permit advancement of the tubing between successive cutting operations, adjustable means capable of limiting inward movement of the or each cutter in accordance with tubing width and wall thickness to provide a generally uniform peripheral cut of controlled depth, and intermittently operable means capable of applying a generally transverse force to the leading end portion of the tubing to break off the leading end portion from the remainder of the tubing after a cutting operation has been performed.

2. Apparatus as set forth in claim 1 wherein a quill is provided between the cutting head and the break-off means, the quill being capable of slidably receiving and holding tubing advanced forwardly through the cutting station and being positioned relative to the break-off means to be capable of supporting the tubing rearwardly of a cut previously made by the at least one cutter before the break-off means is actuated to break off the leading end portion of the tubing forwardly of the quill.

3. Apparatus as set forth in claim 2 wherein a supporting sleeve is spaced forwardly of and axially aligned with the quill, the sleeve being capable of slidably receiving the cut leading end portion and pivotable generally about its rearward end, the break-off means being co-operable with the sleeve to effect a pivoting movement of the sleeve out of its axially aligned position to break off the leading end portion.

4. Apparatus as set forth in any one of the preceding claims wherein the break-off means comprises a powered piston and cylinder and the axis of the cylinder is adapted to lie generally transversely of the tubing.

5. Apparatus as set forth in claim 4 when dependent from claim 3 wherein the piston is pivotally connected to the supporting sleeve, so that the sleeve is re-aligned with the quill by the piston moving in the cylinder for a successive break-off operation.

6. Apparatus as set forth in claim 4 or claim 5 wherein the piston is movable in opposed directions generally parallel to the cylinder axis to break off the leading end portion of tubing and to return to a position for a subsequent successive break-off operation.

7. Apparatus as set forth in any one of the preceding claims wherein the means capable of rotating the cutting head and moving the at least one cutter inwards and outwards comprises a mechanical driving mechanism which is capable of rotating the cutting head and a powered rod and cylinder co-operable with the mechanical driving mechanism to move the or each cutter inwards and outwards.

8. Apparatus as set forth in claim 7 wherein the adjustable limiting means comprises a limit switch which is adjustable to control the extension of the rod relative to its cylinder to limit said inward movement of the or each cutter.

9. Apparatus as set forth in claim 8 wherein the limit switch is mounted on a lead screw which upon rotation is axially advanceable towards the rod to preset the depth of cut into

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. Conventional through-cut "Cut and break technique" Tube Diameter OD - 3/8" Same Material - Soft Copper Same Wall Thickness - .030 thousandths Same ID Reduction - .006 to .008 thousandths .001 thousandths In other tests with the improved tube cutting machine of the present invention, ID reductions as high as .015 (fifteen thousandths) have been reduced to the level of .001 or .002 (one or two thousandths) and even eliminated in the sense that they are so insignificant as to be beyond conventional gauging techniques. The depth of the partial cut prior to break-off is dependent upon wall thickness, diameter of the tubing, type of material, etc. For best results, it is believed that the partial cut should be of a depth approximately 2/3 wall thickness or until a discernible ring or ridge appears in the tube ID opposite cutter engagement. WHAT WE CLAIM IS:

1. Tube severing apparatus comprising means capable of axially advancing elongated tubing in a forward direction to present at a cutting station a leading end portion to be separated from the remainder of the tubing, intermittently operable clamping means adapted to engage the tubing rearwardly of the leading end portion to secure the tubing during cutting, a rotary cutting head at said cutting station having an aperture to receive the leading end portion, said head having at least one rotary cutter adjacent the aperture movable generally inwards and outwards in a direction transverse to the tubing and the aperture to engage and cut into the tubing and to withdraw from engagement therewith, means capable of rotating the cutting head and of moving the or each cutter inwards to perform a cutting operation, said last-mentioned means further enabling movement of the or each cutter outwards to permit advancement of the tubing between successive cutting operations, adjustable means capable of limiting inward movement of the or each cutter in accordance with tubing width and wall thickness to provide a generally uniform peripheral cut of controlled depth, and intermittently operable means capable of applying a generally transverse force to the leading end portion of the tubing to break off the leading end portion from the remainder of the tubing after a cutting operation has been performed.

the tubing by the or each cutter.

10. Apparatus as set forth in any one of claims 7 to 9 wherein the mechanical driving mechanism comprises co-axial first and second pulleys adapted to rotate said head and move the or each cutter, and respective motion transmitting means connecting the second pulley with the or each cutter, said second pulley being angularly displaceable about its axis relative to said first pulley to actuate the respective motion transmitting means to move the respective cutter inwards or outwards upon actuation of said powered rod and cylinder.

11. Apparatus as set forth in claim 10 wherein the second pulley is provided with an internal gear surface, and the respective motion transmitting means has a planet gear engageable with said gear surface and a shaft capable of transmitting movement to the respective cutter, the planet gear being rotatable relative to the second pulley in response to said angular displacement of the second pulley relative to the first pulley.

12. Apparatus as set forth in claim 11 wherein the shaft has an eccentric pin and the respective cutter includes a slide capable of moving generally transversely of the aperture, and a link is connected between the pin and slide to convert arcuate movement of the pin caused by rotation of the shaft about its axis to linear movement of the slide.

13. Apparatus as set forth in claim 12 wherein an adjustment member is received in the slide and has an eccentric pin connected to the link, said member being angularly adjustable in the slide to pre-adjust the transverse position of the slide.

14. Apparatus as set forth in any one of claims 10 to 13 wherein the mechanical driving mechanism comprises a drive pulley connectable to a power source and first and second belts drivable thereby and respectively adapted to drive the first and second pulleys, the second belt extending around a spring-biased take-up pulley, and wherein displacement of the rod of the powered rod and cylinder is adapted to displace the belt, the take-up pulley being moved upon displacement of the belt, whereby the second pulley is angularly displaced with respect to the first pulley to move the or each cutter.

15. Apparatus as set forth in claim 14 wherein displacement of the rod is adapted to pivot a lever carrying a roller which engages the second belt whereby such pivotal movement effects displacement of the roller to displace the belt.

16. Apparatus as set forth in any one of the preceding claims wherein three peripherally spaced rotary cutters are provided on the cutting head.

17. Tube severing apparatus substantially as herein described with reference to the accompanying drawings.

18. Apparatus as set forth in claim 1 and including intermittently operable break-off means substantially as herein described with reference to Figures 1 and 2 of the accompanying drawings.

19. Apparatus as set forth in claim 1 and including intermittently operable break-off means substantially as herein described with reference to Figure 6 of the accompanying drawings.

20. A method of severing elongated tubing comprising the steps of: a) axially advancing tubing in a forward direction to present a leading end portion, to be separated from the remainder of the tubing, at a cutting station where the leading end portion is received in an aperture of a rotary cutting head having at least one rotary cutter; b) clamping the tubing rearwardly of the leading end portion; c)rotating said cutting head and moving the at least one rotary cutter inwards in a direction transversely of the tubing and the aperture to engage and cut into the tubing; d) limiting the depth of cut in accordance with tubing width and wall thickness to provide a generally uniform peripheral cut of controlled depth; e) applying a generally transverse force to the leading end portion to break off the leading end portion of the tubing; f) moving the at least one rotary cutter outwards in a direction transversely of the tubing and the aperture and thereby withdrawing the at least one cutter from engagement with the tubing before or after the step of applying said generally transverse force, and g) further axially advancing the remainder of the tubing in a forward direction to present a leading end portion of said remainder at the cutting station for successive cutting and break-off operations.

21. A method as set forth in claim 20 including axially advancing the leading end portion of the tubing in the forward direction after a peripheral cut of controlled depth has been made and after the at least one rotary cutter has been withdrawn from engagement with the tubing, and supporting the tubing at a position rearwardly of the cut but forwardly of the cutting head before the step of applying the transverse force to break off the leading end portion of the tubing.

22. A method as set forth in claim 21 wherein substantially simultaneously as a leading end portion of the tubing is being broken off another peripheral cut of controlled depth is being made by the at least one rotary cutter at a location along the tubing spaced rearwardly from the first-mentioned cut.

23. A method as set forth in claim 21 or claim 22 wherein the leading end portion of the tubing is supported forwardly of the first-mentioned cut while it is broken off from the remainder of the tubing.

24. A method of severing elongated tubing as set forth in any one of claims 20 to 23 and substantially as herein described with reference to the accompanying drawings.

25. A length of tubing in which at least one end has been severed by the method according to any one of claims 20 to 24.