US3893263A

US3893263A - Tapering tool

Info

Publication number: US3893263A
Application number: US504342A
Authority: US
Inventors: Robert M Jackman; William N Mcdonald
Original assignee: AO Smith Inland Inc
Current assignee: AO Smith Inland Inc
Priority date: 1974-09-09
Filing date: 1974-09-09
Publication date: 1975-07-08
Anticipated expiration: 1992-07-08
Also published as: CA1031965A

Abstract

A tapering tool for tapering the end of a pipe or tube made of fiber reinforced plastic pipe to provide a feathered edge on the pipe. The tool has a slide pivoted to the housing of the tool at one end and which supports a grinding drum that can be slid longitudinally of the slide or tilted angularly by adjusting the arcuate movement of the slide to locate the drum in different positions for tapering the pipe end. The slide at the outer end has a pawl reciprocated by a motor in synchronism with rotation of the mandrel by the motor upon which the pipe to be tapered is disposed. The pawl in turn rotates a ratchet and thereby a cam which reciprocates a connecting rod secured to the slide. Each time the mandrel makes a complete rotation the pawl strokes the ratchet connected to the cam, and the cam is moved one increment to tilt the slide carrying the grinding drum toward the pipe to be tapered. The cam travels 180* and then the direction of tilt reverses. The cam can be actuated manually to initially start the tilt of the slide and return the slide to start position. An adjustment is provided at the outer end of the slide and tool housing to change the arcuate movement of the slide carrying the drum and the consequent angle of taper of the feathered edge formed on the pipe. A rod is threaded through the support for the grinding drum to effect longitudinal adjustment of the support for the drum within the slide to locate the drum in different positions depending on the diameter of the tube to be tapered and the thickness desired in the feathered edge. A second motor rotates the grinding drum.

Description

United States Patent [1 1 Jackman et al.

[ TAPERING TOOL [75] Inventors: Robert M. Jackman; William N.

McDonald, both of Little Rock, Ark.

[73] Assignee: A. O. Smith-Inland, Inc.,

Milwaukee, Wis.

[22] Filed: Sept. 9, 1974 [21] Appl. No.: 504,342

[52] U.S. Cl. 51/105 R; 51/237 R [5 l] Int. Cl B24b 9/00; B24b 41/10 [58] Field of Search 51/72 R, 103 C, I05 R,

51/237 R, 241 S, 241 B, 50 R [56] References Cited UNITED STATES PATENTS 2,455,762 l2/l948 Hall 5l/24l B 2,587,398 2/1952 Smith 5l/24l S 3,088,249 5/1963 Pope et al, 5l/l05 R 3,187,738 6/[965 Christopher l25/l3 R 150L872 3/1970 Mighton 5l/24l B Primary Examiner0thell M, Simpson Attorney, Agent, or Firm-Andrus, Sceales, Starke & Sawall [57] ABSTRACT A tapering tool for tapering the end of a pipe or tube made of fiber reinforced plastic pipe to provide a [451 Jul 8,1975

feathered edge on the pipe. The tool has a slide pivoted to the housing of the tool at one end and which supports a grinding drum that can be slid longitudi nally of the slide or tilted angularly by adjusting the arcuate movement of the slide to locate the drum in different positions for tapering the pipe end. The slide at the outer end has a pawl reciprocated by a motor in synchronism with rotation of the mandrel by the motor upon which the pipe to be tapered is disposed. The pawl in turn rotates a ratchet and thereby a cam which reciprocates a connecting rod secured to the slide. Each time the mandrel makes a complete rotation the pawl strokes the ratchet connected to the cam, and the cam is moved one increment to tilt the slide carrying the grinding drum toward the pipe to be tapered. The cam travels 180 and then the direction of tilt reverses. The cam can be actuated manually to initially start the tilt of the slide and return the slide to start position. An adjustment is provided at the outer end of the slide and tool housing to change the arcuate movement of the slide carrying the drum and the consequent angle of taper of the feathered edge formed on the pipe. A rod is threaded through the support for the grinding drum to effect longitudinal adjustment of the support for the drum within the slide to locate the drum in different positions depending on the diameter of the tube to be tapered and the thickness desired in the feathered edge. A second motor rotates the grinding drum.

9 Claims, 8 Drawing Figures PMENTEUJUL I 8 ms SHEET an iii!!! PATENTED JUL 1915 SHEET 25B kwnziu @Io 20 E t PATENTEUJUL' 81915 SHEET SHEET PATENTE'DJUL 8 I975 1 TAPERING TOOL BACKGROUND OF THE INVENTION At least one end of a hollow tubular workpiece or pipe made of fiber reinforced plastic must be tapered to a feathered edge to match the bell taper of the end of the pipe within which it is received to complete the joint between the two pipes. Previously the tools employed have been flat grinding discs or grinding drums without an automatic advance and withdrawal system. In the past systems the workpiece was manually turned and fed by the operator to the grinding apparatus. This resulted in uneven surfaces to be glued together and consequent weak joints. The tapering tool of the invention is semi-automatic to accomplish the tapering operation in that it is self-feeding by tilting the tapering mechanism into the pipe end and can be automatically removed therefrom or it can be manually actuated to initiate the tilting movement and to return the tapering mechanism to start position. This feeding mechanism is linked to the pipe rotating mechanism so that rotation of the pipe to be tapered is synchronized with the automatic movement of the mechanism against the end of the pipe to be tapered. The automatic features of the tool of the invention eliminate the problems developed by the tools previously used.

SUMMARY OF THE INVENTION In general the tapering or grinding tool of the invention has an elongated housing from the center of which extends a mandrel having circular plates of a size to receive a pipe to be tapered and is adapted to engage the inside of the pipe and securely hold the same when the mandrel is rotated. Means are provided to increase the holding effect of the mandrel plates.

Inside one end of the housing there is located a slide or carriage which is pivoted to the upper and lower members of the housing at the inner end but is free at the outer end so that the slide can be tilted or rotated away from the housing in an arcuate path.

The slide carries internally a support for a gear motor on one side of the housing and for a grinding drum on the opposite side of the housing. A shaft inside the drum is coupled to the drive shaft of the motor so that the motor when actuated rotates the drum. The support for the drum is movable longitudinally within the slide to move the drum for tapering pipes of varying diameter and to regulate the thickness of the feather edge. The longitudinal movement is accomplished by a rod threaded to the support and extending therethrough which is actuated by a hand wheel at the outer end of the slide.

In addition angular movement of the slide to move the drum toward the pipe to be tapered is synchronized with the rotation of the mandrel. A cam on the hollow tube of the mandrel is rotated with the mandrel and reciprocates a connecting rod which is secured to a plate or arm connected by bolts extending in oblong apertures in a side plate of the housing. The outer end of the reciprocated plate carries a pawl which engages a ratchet located at the outer end of the slide. Each time the pawl strokes, the ratchet advances one click or increment. A cam which is connected to the ratchet then rotates and tilts the slide toward the pipe to be tapered through a connecting rod which is secured to the outer end of the slide. The grinding drum is thus advanced in increments toward and against the pipe until the cam travels when the direction of tilt of the slide reverses. The ratchet can also be operated manually to initiate the start of the tilt of the slide and to return the slide to start position.

The arcuate path of the slide carrying the drum can be changed to control the angle of the taper of the pipe end by an adjusting knob which upon rotation changes the movement of the connecting rod driven by the cam.

The drum is partially enclosed in a dust cover to which a vacuum is applied to remove the material ground from the end of the pipe.

DESCRIPTION OF THE DRAWINGS FIG. I is a top plan view of the tool of the invention with parts in section and illustrating the starting position of the slide and drum carried by the slide;

FIG. 2 is a side elevational view of the tool taken on line 2-2 of FIG. 1',

FIG. 3 is a view similar to FIG. 2 but of the opposite side of the tool;

FIG. 4 is a sectional view of the tool with parts in elevation;

FIG. 5 is an end view of the tool at the pawl and ratchet end taken on line 5-5 of FIG. 2;

FIG. 6 is a detail schematic view particularly illustrating the slide and the pawl and ratchet arrangement;

FIG. 7 is a perspective view of the slide with parts in section; and

FIG. 8 is a view of the pipe after tapering with parts broken away and sectioned to illustrate the taper.

DETAILED DESCRIPTION OF THE INVENTION Referring to the drawings, the tapering tool of the invention has an elongated housing defined by upper plate member 1 and lower plate member 2. One side of the housing is closed by the side plate 3 and a second side plate 4 which has an oval-shaped opening 5 therein. The upper and lower plates are bolted to

side plates

3 and 4. The side of the housing

opposite plates

3 and 4 is generally open. At one end inside the housing is located the outlet box 6 which is connected to a source of power, not shown, for operation of the several motors employed in the tool. The upper plate I and lower plate 2 are bolted to outlet box 6 to hold it inside the housing, and the box also gives support to the plates as shown in FIG. 3.

At the center of the housing is a mandrel 7 upon which is located the pipe 8 which is to be tapered by the tool.

The mandrel consists of the elongated hollow mandrel tube 9 which extends outwardly from one side of the tool housing and is supported within the housing by the block 10 disposed between

side plates

3 and 4. Block 10 is bolted to the upper plate I and lower plate 2 of the housing.

The outer end of hollow mandrel tube 9 is closed by the end member 11 and sleeve 12 which are welded together and fit over the outboard end of mandrel tube 9.

A shaft 13 extends through the center of mandrel tube 9 and the outer end of the shaft has threads l4 which are threaded into end member 11. A stop disc 15 is welded inside the outer end of mandrel tube 9 a short distance from the end and the shaft 13 extends freely through disc 15. A stop ring 16 is welded to shaft 13 outboard of stop disc 15 and as shaft 13 is rotated the stop ring 16 limits the movement of shaft 13 between end member 11 and stop disc 15.

The inner end of shaft 13 projects through the cap 17 outwardly of the tool housing, and a hand wheel 18 is secured to the end of shaft 13 so that shaft 13 may be manually rotated. A lock nut 19 is located on the end of mandrel tube 9 and tangs on the lock washer 20 as sembled on mandrel tube 9 are bent into notches in nut 19 to lock it after shaft 13 is in place and clearance adjusted.

The sleeve bearing 21 extends around mandrel tube 9 inside of block 10 and is flanged at both ends to engage the ends of block 10 to hold the sleeve in place. The mandrel tube 9 rotates in the sleeve bearing 2].

The tubes 22 located outwardly of block 10 and outside the hollow sleeve 23 are short straight tubes. Tubes 22 are welded to the spaced circular plates 24 and a ring 22a is also located between plates 24 and welded thereto outside of tubes 22.

Spacer tubes

25 and 25a are located around mandrel tube 9 longitudinally outwardly of sleeve 23.

In the illustration of the mandrel 7 in the drawing, there is shown a pair of

circular mandrel plates

26 and 27 disposed at the outer end of mandrel tube 9 and a second pair of

mandrel plates

28 and 29 located adjacent the inner end of mandrel tube 9. Both pair of mandrel plates are interchangeable and encircle the mandrel tube 9 and are of a diameter to receive a tubular workpiece to be tapered such as the fiber glass reinforced plastic pipe 8 shown in FIG. 1 of the drawings.

The

mandrel plates

26 and 27 are disposed between the outer end of the spacer tube 25 and the ring 30 which is welded to sleeve 12. A gusset 31 which com prises a reinforcing web and a plate abutting the side of mandrel plate 27 is welded to spacer tube 25 and

plates

26 and 27 are thereby confined between ring 30, forming part of the cap at the end of the mandrel tube 9, gusset 31 and spacer tube 25.

Plates

26 and 27 are separated by the spring belting 32 which rests in a groove 33 provided by tapering the plates at their outer facing ends. The belting 32 normally tends to spread the slates apart against the opposition of the spring assem- Jly 34 disposed in an opening 35 in

plates

26 and 27.

The mandrel 7 is reinforced centrally by a pair of gusiet plates 36 and 360, the plate 36 being welded to ipacer tube 25 and the plate 360 to spacer tube 250.

The

mandrel plates

28 and 29 at the inner end of ipacer tube 250 encircle mandrel tube 9 between the nner end of spacer tube 250 and the outer end of ilV 23 and the outermost plate 24 which abuts manlrel plate 29.

The gusset 37 consisting of a reinforcing web and a :ircular plate is welded to spacer tube 250 and abuts he mandrel plate 28. As in the case of the other pair )f mandrel plates previously described, the plates are nwardly tapered to provide a groove 38. The spring ielting 39 is lodged in the groove and normally tends o spread the

mandrel plates

28 and 29 apart against he opposition of the spring assembly 40 disposed in 10th of

plates

28 and 29.

After the pipe 8 to be tapered is assembled on the

nandrel plates

26 and 27, and 28 and 29, the hand vheel 18 is rotated to move the cap provided by end nember ll, sleeve 12 and ring 30 inwardly against ilate 26 because wheel 18 turns shaft 13 which is hreaded into end member 11. This compresses the nandrel plates and thereby expands the spring belting 32 and 39 outwardly to grip the inner surface of pipe 8 and anchor it on the mandrel 7 for rotation. Unscrewing ofthe shaft 13 releases the mandrel so that the pipe 8 can be withdrawn after tapering. The inward assembly movement of pipe 8 on the mandrel plates is re stricted by the stop bar assembly 41 to prevent sliding of the pipe too far inwardly for accomplishing the tapering operation. Stop bar assembly 41 is bolted to upper plate 1 by bolts 42 extending through elongated slots 43 thereby permitting adjustment of the bar assembly 41 to different positions. When the mandrel 7 has been tightened to hold pipe 8, the stop bar assembly 41 is loosened and withdrawn to prevent interference when pipe 8 is rotated.

The mandrel tube 9 is rotated clockwise by a sprocket and chain drive which also can rotate the grinding tool around the pipe if the pipe is of a length which is difficult to rotate and in such case the pipe is held stationary. The sprocket and chain drive Consists of a gear motor 44, part of which is located within the tapering tool housing and bolted to plate 3 of the housing. The shaft 45 of motor 44 extends through side plate 3 and is secured to chain sprocket 46 to rotate the sprocket. An idler sprocket 47 is secured to an idler bracket 48 which has an elongated aperture 49 for securing idler sprocket 47 to side plate 3 by a screw 50 which can be loosened to move bracket 48 and thereby tighten endless chain 51 which extends around chain sprocket 46 and on the inside of idler sprocket 47.

A generally large diameter sprocket 52 is welded to the mandrel tube 9 and the chain 51 extends around sprocket 52 so that rotation of the sprocket 46 by motor 44 effects rotation of sprocket 52 and mandrel tube 9. The sprocket 52 also rotates in frictional engagement with the plate or collar 53 freely assembled on tube 9. The

mandrel plates

26 and 27 and 28 and 29 as well as

spacer tubes

25 and 25a and gussets 3], 36, 36a and 37 are slip fitted over the mandrel tube 9. Thus when shaft 13 is rotated to tighten the cap formed by end member 11, sleeve 12 and plate 30 against the outer mandrel plate 26, this compresses the entire assembly together and against plate 53 to increase the frictional engagement of plate 53 with sprocket 46 and inner plate 24. This effects rotation of the mandrel plates and the spacer tubes and gussets by mandrel tube 9.

A chain guard, not shown, is ordinarily provided around the sprockets and chain 51 to protect the operator of the tool against injury.

The grinding unit is located on the opposite side of mandrel 7 from gear motor 44. The grinding unit consists of the grinding motor 54 which is secured to the coupling housing 55 by cap screws 56 extending through end plate 57 on the inner end of the motor and a flange 58 on the outer end of the coupling housing 55.

The inner end of the coupling housing 55 has a flange 59 which is bolted to the plate 60 on block 61. The opposite end of block 61 has a flange 62 spaced from plate 60, and both plate 60 and flange 62 project up wardly and downwardly from the body of block 61 so that recesses 63 are provided centrally between plate 60 and flange 62 in both the bottom and top of block 61.

The bearing housing 64 is secured within block 61 and projects therefrom through the oval opening 5 in side plate 4. Inside of bearing housing 64 is a shaft 65 which is joined to the motor shaft 66 by the coupling 67 and driven by shaft 66. Shaft rotates in the bearings 68 inside of housing 64 and extends forwardly inside of the grinding drum 69. Drum 69 on the inner end engages an abutment 70 on shaft 65 and is held on the end ofthe shaft 65 by nut 71 which is threaded onto the outer protruding end of shaft 65. The drum is partially enclosed within a dust shield 72 shown in dotted lines in FIG. 1 and has a wheel guard, which is not shown, and is connected to a source of vacuum, also not shown. The drum is of carbide grit or is diamond coated, and is rotated counterclockwise as the workpiece 8 is rotated clockwise.

The block 61 is encompassed within a slide or carriage 73 which comprises the upper plate 74 lodged within the upper recess 63 of block 61 and the lower plate 75 which is received within the lower recess 63 of block 61. The inner ends of

plates

74 and 75 are secured to the block 76 and block 76 is pivoted by pin 77 to top plate 1 and bottom plate 2 of the housing to thereby pivot slide 73 thereto.

The outer ends of

plates

74 and 75 are secured to the block 78 which is free to move a predetermined distance when the slide 73 is rotated. Longitudinal adjustment of the slide 73 to move drum 69 and grind pipes 8 of different diameters is accomplished by the threaded rod or screw 79 which is threaded through the lower part of the flange 62 of block 61 and is rotated at its inner end within a projecting member 80 secured to block 76 and at its outer end in the lower portion of the block 78. The rotation of rod 79 is accomplished by the size adjusting crank 81 secured to the outer end of rod 79. Because of the threaded engagement of the rod 79 with block 61, rotation of rod 79 effects longitudinal movement of the block 61 and consequently the drum 69 is moved toward or away from mandrel 7 depending on the size of the pipe 8 which is to be tapered and to obtain the predetermined thickness desired of the feathered edge on pipe 8.

Numbers located on the top plate 1 of the housing, as may be observed in FIG. 1, give an indication of the location of the block 61 and drum 69 by indicating the diameter of the pipe 8 which is to be tapered.

Once the drum 69 has been located in the proper longitudinal position, the size adjusting crank 81 is locked into position by the spring held pin 82 on bracket 83 secured to the carriage of the tool being lodged in a detent in the collar 84 of the crank 81.

In order to accomplish the tilting or rotation of slide 73 to different angular positions to engage pipe 8, cam 85 is welded to the mandrel tube 9 of the mandrel 7 and cam 85 is rotated by mandrel tube 9 of mandrel 7 to reciprocate the connecting rod 86. Rod 86 is connected to the sliding plate or arm 87 by pin 88 and plate 87 has a large oval opening 89 in line with the oval opening 5 in side plate 4 to permit passage therethrough of the bearing housing 64 and drive shaft 65 of the drum 69 driven from motor shaft 66. The plate 87 is anchored to the side plate 4 by four shoulder screws 90 extending through oblong holes in plate 4 and is free to slide under the screw heads. The plate 87 is thus reciprocated by the connecting rod 86 and the cam 85.

The outer end of sliding plate 87 carries a pawl 91 which is pivoted to a bracket 92 secured to the plate 87 and pressed by spring 94 into engagement with the teeth of the ratchet 93 to effect rotation of the ratchet. A spring 94a as illustrated diagrammatically in FIG. 6 has a tang disposed to snap it into engagement with the ratchet 93 as pawl 91 reverses for the next stroke to prevent backlash of ratchet 93.

The sliding movement of plate 87 effected by connecting rod 86 and cam 85 upon rotation of the man drel tube 9 of mandrel 7 moves pawl 91 in a reciprocating motion to advance pawl 91 one stroke per revolution of mandrel tube 9 to thus rotate the ratchet 93. The ratchet 93 is confined within the bracket 95 and cap 96 which are bolted together. The bracket 95 is bolted to the side plate 4 of the housing. The shaft 97 extends through the eccentric cam 98 which is keyed to ratchet 93 at one end of shaft 97 and the shaft 97 in turn is keyed to the cam 98. Cam 98 is located inside the connecting rod 99 and the grinding feed knob 100 is pinned to the other end of shaft 97. Each time the pawl 91 makes one stroke, ratchet 93 rotates to ad vance cam 98 one stroke. and because cam 98 is con-- nected to one end of connecting rod 99, the connecting rod 99 is then reciprocated. The other end of the connecting rod 99 extends within the clevis 101 and is secured thereto by the dowel pin 102. The clevis 101 is disposed within the block 78 which is bolted, as previously described, to

plates

74 and 75 of slide 73. An outer plate 103 and inner plate 104 are bolted to block 78 to contain clevis 101. The clevis 10] is moved by connecting rod 99 and this moves block 78 and tilts the entire slide 73, carrying drum 69 with it.

The clevis 101 is secured to the threaded bolt 105 by the pin 106 and bolt 105 extends therefrom through the threaded nut 107 and outwardly thereof through block 78. The knurled knob 108 extends around nut 107 and is secured to nut 107 by set screw 109. The lock nut 110 is threaded onto the outboard end of threaded bolt 105 and against knurled nut 108.

When lock nut 110 is loosened turning of the knurled knob 108 can be accomplished, and this results in adjustment of the throw of connecting rod 99 and the degree of the arcuate travel of the slide 73 when it pivots drum 69 to grind the taper on pipe 8. When the knurled knob 108 is adjusted to the desired taper angle the lock nut 110 is tightened to prevent movement of bolt 105. Knob 108 when turned clockwise decreases the angle of taper on pipe 8 and when turned counterclockwise the angle of taper is increased. A change in the taper angle setting will change the angle of the feathered edge of pipe 8. This may require further adjustment by turning the crank 81 clockwise to move drum 69 longitudinally of the tool housing to decrease the thickness of the feathered edge on pipe 8.

For each revolution of the mandrel tube 9, the ratchet 93 moves one-twenty fourth of a revolution to reciprocate connecting rod 99. This continues until the cam 98 travels l80 and then the direction of tilt reverses. Each click of ratchet 93 then moves the grinding drum 69 for away from pipe 8 which removes the load from drum 69 and the grinding motor 54, and the latter returns to no-load speed.

Because the cam 98 is operable for 360", that is 180 to advance the grinding drum and 180 to retract the drum 69 from the workpiece 8, it takes about 12 minutes to automatically return the drum to start position. Therefore the feed knob 100 may be employed to manually rotate the cam 98 after the tapering operation to in less time return the cam 98 and ratchet 93 to the start position, as illustrated in FIG. 1, and to enable immediate actuation of the connecting rod 99 to tilt the slide 73 when the next tapering operation is commenced. Manual rotation of feed knob 100 rotates shaft 97 and cam 98 and effects the return of cam 98 and ratchet 93 to the start position. If the cam 98 were not manually rotated to start position. pipe 8 would have to be rotated twelve times to return the cam 98, ratchet 93, slide 73 and the grinding drum 69 to the start position.

Another feature of the invention is that it is possible to rotate the entire tapering tool should that be desirable rather than rotate the pipe 8 so that the grinding drum 69 is rotated around the pipe 8 as the drum itself rotates.

Also, the tool may have pipes or bars secured to the lower plate of the housing so that it may be secured to a table or like support when in service.

In the operation of the machine the size adjusting crank 81 is rotated to move the grinding drum 69 connected to block 61 by means of the threaded rod 79 to the proper position for the approximate feathered edge thickness. The arrow on slide 73 is matched with the desired number on the top plate 1, as illustrated in FIG. 1, to obtain the correct dimension.

The grinder feed knob 100 is then turned to the start position as illustrated in FIG. 1. The mandrel 7 having the

plates

26 and 27 and 28 and 29 of the size to receive and hold the pipe 8 is then assembled on the tool. Pipe 8 is next slid onto the mandrel 7 until it engages the stop bar 41 and then is pulled back about onequarter of an inch to provide a relief for slight movement of the pipe upon thereafter expanding of the

mandrel plates

26 and 27 and

plates

28 and 29. The hand wheel 18 is rotated to rotate shaft 13 to compress the mandrel plates and expand the belting 32 and 39 into holding engagement with the inside of pipe 8 and place the assembly into frictional engagement with collar 53.

A source of vacuum, not shown, is connected to the dust shield 72 so that dust can be removed from the area of the grinding drum 69 to prevent loading of dust onto the tool during the grinding operation which might cause binding of moving parts and excessive wear. Next the grinding motor 54 is started to bring it up to speed and the motor will at that time be free of pipe 8, as illustrated in the start position of the slide 73 in FIG. 1.

The gear driving motor 44 is then started and, to save time, the grinding drum 69 is tilted toward pipe 8 by turning the grinder feed knob 100 one increment at a time until drum 69 engages pipe 8 and begins to lightly grind pipe 8. Then the knob 100 is released and the au tomatic operation of the tool takes over.

The grinding operation is accomplished automatically by rotation of the mandrel 7 by motor 44 and reciprocation of pawl 91 in engagement with ratchet 93 which actuates the eccentric cam 98 and connecting rod 99 secured to the slide 73 to advance the grinding drum 69 as it is rotated by the grinding motor 54 to complete the taper of the end of pipe. On start of the grinding operation the initial lift of cam 98 is substan tial, allowing the grinding drum 69 to take bigger bites of the pipe 8 where the amount of material being re moved per revolution of the pipe 8 and drum 69 is less because of the shorter contact area with the pipe surface. As the cam approaches its maximum lift, the movement becomes incrementally smaller until at the last increment the drum 69 barely advances, giving the drum an opportunity to make a light finishing cut for good surface uniformity. Also, as the final cut is approached, the maximum surface of the pipe 8 is in contact with the drum 69 and the shallow bites obtained are desirable to prevent bogging down. After cam 98 has rotated 180 it goes over top center and advance of the drum 69 is discontinued. Drum 69 is then withdrawn very slowly thereby preventing undesirable burrowing and grooves. When the drum 69 is free of the pipe 8, the grinder feed knob 100 is manually rotated to turn the knob 100 to the start position and the slide 73 will then be in the position as illustrated in FIG. 1. The motors are then stopped and the pipe 8 is removed from the mandrel 7 and the feathered edge thickness and the taper angle are checked with a micrometer or otherwise.

If it is necessary to adjust the taper angle. the lock nut 110 is loosened to release the knurled knob 108 which can then be rotated in either direction to move the threaded bolt inwardly or outwardly and thus change the throw of the connecting rod 99 actuated by eccentric cam 98 and the angle of tilt of the slide 73. When the desired angle is obtained lock nut 110 is tightened to hold knurled knob 108 in the determined position. The knob 108 is turned clockwise to decrease the angle of tilt and counterclockwise to increase the angle. For example, one revolution of knob 108 will change the angle by twelve minutes or 0.003 inches per inch.

A change in the taper angle setting will also change the angle of the feathered edge of pipe 8. The thickness of the feathered edge can be changed by rotation of the size adjusting crank 81 to adjust the drum 69 longitudinally of the tool housing. If crank 81 is rotated clockwise, the thickness of the feathered edge of pipe 8 is decreased, and when crank 81 is rotated counterclockwise, the thickness of the feathered edge is increased. For example, one revolution of the crank 81 will change the thickness of the feathered edge of pipe 8 by 0.050 inches.

Another feature of the invention is that the parts of the mandrel 7 are interchangeable in order to taper pipe of different lengths. The two mandrel assemblies consisting of28, 29, 38, 39 and 40 are identical to

mandrel assemblies

26, 27, 32, 33, 34 and 35. Also the two spacers consisting of

tubes

25 and 25a,

gusset plates

36 and

36a gussets

31 and 37 are identical. Each pair of gussets and a spacer tube are welded together to form integral pieces and are slip fitted on mandrel tube 9 along with the circular mandrel plates so that they can be removed and reassembled in other manners in order to hold a pipe shorter than the pipe 8 shown in FIG. 1. Thus, for example, referring to FIG. 4, only the

gusset plates

31 and 36 joined by spacer 25 would be located between the pair of

mandrel plates

26 and 27 and the other pair of

plates

28 and 29. The

gusset plates

36a and 37 joined by spacer 25a would then be assembled on the outer end of the mandrel tube 9 outboard of the

mandrel plates

26 and 27. A much shorter workpiece 8 could then be held on the mandrel 7 for tapering the end.

Various operations of the tool may be used to obtain the correct taper of a pipe end and to check the taper and thickness of the pipe end.

By providing a tapering tool which is operated semi automatically, time is saved by manually tilting the slide carrying the grinding drum into initial position and back to start while utilizing the automatic features of the machine to insure the obtaining of the desired angle of taper and thickness in the feathered edge formed on the end of the pipe to which the tool is applied.

Various modes of carrying out the invention are contemplated as being within the scope of the following claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention.

We claim:

1. A machine for tapering a feathered edge on the end of a hollow tubular workpiece which comprises, an elongated housing having upper and lower members and at least one side member which are secured together to form the housing, a mandrel secured to the housing generally centrally thereof and extending therefrom to receive the workpiece to be tapered, a slide member having upper and lower members secured to fixed support members at the inner and outer ends and confining an intermediate support member free to be moved longitudinally of the slide, said slide member being located to one side of the mandrel within the housing and pivoted at the inner end to said housing with the outer end of the slide member being free to be moved outwardly of the housing in an arcuate path, a rotatable grinding drum supported in the intermediate support member and extending outwardly of the slide and housing through an elongated opening from the same side of the housing as the mandrel and disposed to be placed in engagement with the end of the workpiece to be tapered, means connected to the intermediate support to move the latter longitudinally within the slide together with the drum carried thereon to locate the drum relative to workpieces of varying diameter and for obtaining the predetermined thickness in the feathered edge to be formed on the workpiece, an eccentric cam connected to the outer support of the slide and disposed to be driven in incremental movements to tilt the slide and the grinding drum into engagement with the end of the workpiece to be tapered and to remove the same therefrom, and driving means assembled with the housing to actuate relative rotation of the grinding drum and workpiece and to drive the eccentric cam in synchronism therewith to taper a feathered edge on an end of the workpiece to predetermined dimensions.

2. The machine of claim 1, and means connected to said eccentric cam to drive the same automatically and to manually rotate the cam to initially place the grinding drum in contact with the workpiece and to tilt the slide member carrying the drum back to a start position once the taper of the end of the workpiece is completed to reduce the time required to tilt the workpiece to start position by incremental movement by the automatic actuation of the cam.

3. The machine of claim 2, wherein the mandrel receiving the workpiece to be tapered comprises a hollow rotatable mandrel tube on which is assembled reinforcing spacers and gusset plates and circular plates with resilient material disposed between the circular plates, a shaft extending through the mandrel tube and connected to an operating means at the inner end and having threads at the outer end threaded into a cap member overlying the outboard end of the mandrel tube so that when the shaft is rotated by the mandrel tube the cap is moved inwardly to compress the spacers, gusset plates and mandrel plates and expand the resilient material into holding engagement with the assembled workpiece, a collar assembled on the mandrel tube adjacent the inner end of the latter, a sprocket secured to the mandrel tube inside the collar and disposed in frictional driving engagement with said collar, said collar in turn being disposed to frictionally rotate the mandrel plates, spacers and gussets after compression thereof by said cap, the driving means including a motor secured to said housing, a sprocket connected to the motor and rotated thereby, and a chain connecting the respective sprockets to effect rotation of the mandrel tube and thereby rotation of the workpiece.

4. The machine of claim 3, wherein a cam is secured to the mandrel tube adjacent the inner end of the tube, said cam being rotated simultaneously when the mandrel tube of the mandrel is rotated, a connecting rod reciprocated by said cam as the latter rotates, an arm connected at one end to the connecting rod and secured to a side plate of the housing in a manner permitting reciprocating movement relative to said side plate, a pawl connected to the outer end of said arm, a ratchet engaged by the pawl to effect incremental rotation of the ratchet, an eccentric cam secured to the ratchet and driven intermittently by the ratchet upon reciprocation of said arm, a connecting rod connected to the slide and reciprocated by the last named cam, and a single rotation of the mandrel tube effecting said one increment of movement of the cam rotated by the pawl and ratchet to tilt the slide in successive one increments of movement and thereby move the grinding drum in incremental movements in an arcuate path toward or away from the workpiece.

5. The machine of claim 4, and the connecting rod reciprocated by said eccentric cam being secured to the outer support member of the slide, means to adjust the throw of the connecting rod, said means comprising a threaded member secured at one end to said last named connecting rod and extending through a threaded nut and a wall of said support member at the other end, a knurled nut overlying the threaded nut and secured thereto and adapted upon rotation to rotate said nut and move the threaded member inwardly or outwardly of the support member to set the throw of the connecting rod, and a lock nut rotatable into engagement with the knurled nut to lock the latter into fixed position when the throw of the connecting rod has been established.

6. The machine of claim 2, in which the driving means includes a grinding motor secured to the intermediate support member in the slide, a drive shaft extending from the motor within the intermediate support member, a driven shaft connected to the grinding drum, a coupling member joining the two shafts to rotate the drum from the grinding motor, and a dust shield assembled partially around the grinding drum to collect and effect drawing off of dust and ground particles when a vacuum is applied thereto.

7. The machine of claim 2, in which the means connected to the intermediate support is a rod threaded through the intermediate support and lodged at the inner end in the inner support member and at the outer end extending through the outer support member and outwardly therefrom, a size adjusting crank secured to the outer end of the threaded rod and having a collar with a plurality of detents circumferentially spaced thereabout, and a bracket fixed to the housing and having a spring held member therein adapted to engage a detent in said collar and hold the threaded rod against rotation when the intermediate block is located in the desired position within said slide.

8. The machine of claim 2, and a bar secured to the upper member of the housing and extending toward the workpiece, and means on the housing to adjust the bar to different positions to locate the workpiece at different longitudinal positions on the workpiece a rod extending through the mandrel tube and threaded at the outer end, a cap at the outer end of the mandrel tube into which the rod is threaded, and a hand wheel secured to the inner end of the rod to rotate the rod and pull the cap inwardly of the mandrel tube to compress the mandrel plates 9. In a machine having a housing supporting a mandrel to receive and rotate a tubular workpiece for ta pering the end thereof to a feathered edge by a grinding drum, a carriage pivoted at one end inside the housing and free at the outer end to be tilted in an arcuate path toward said workpiece, a ratchet and eccentric cam connected to the outer end of the carriage. a pawl con nected to said housing in engagement with said ratchet and adapted to be reciprocated when the workpiece is rotated to rotate the ratchet and cam and thereby tilt the carriage toward the workpiece, a motor secured to the carriage and connected to the grinding drum to rotate the latter, a manually operated member secured to a shaft disposed in driving engagement with said cam to thereby manually actuate the cam and effect initial tilt of the carriage and to move the carriage back to start position when the grinding operation is completed, and means in the carriage to move the grinding drum longitudinally therein and therefore toward or away from the workpiece to taper workpieces of different diameter and govern the thickness of the taper.

Claims

8. The machine of claim 2, and a bar secured to the upper member of the housing and extending toward the workpiece, and means on the housing to adjust the bar to different positions to locate the workpiece at different longitudinal positions on the workpiece, a rod extending through the mandrel tube and threaded at the outer end, a cap at the outer end of the mandrel tube into which the rod is threaded, and a hand wheel secured to the inner end of the rod to rotate the rod and pull the cap inwardly of the mandrel tube to compress the mandrel plates.

9. In a machine having a housing supporting a mandrel to receive and rotate a tubular workpiece for tapering the end thereof to a feathered edge by a grinding drum, a carriage pivoted at one end inside the housing and free at the outer end to be tilted in an arcuate path toward said workpiece, a ratchet and eccentric cam connected to the outer end of the carriage, a pawl connected to said housing in engagement with said ratchet and adapted to be reciprocated when the workpiece is rotated to rotate the ratchet and cam and thereby tilt the carriage toward the workpiece, a motor secured to the carriage and connected to the grinding drum to rotate the latter, a manually operated member secured to a shaft disposed in driving engagement with said cam to thereby manually actuate the cam and effect initial tilt of the carriage and to move the carriage back to start position when the grinding operation is completed, and means in the carriage to move the grinding drum longitudinally therein and therefore toward or away from the workpiece to taper workpieces of different diameter and govern the thickness of the taper.