US2125686A

US2125686A - Rolling mill

Info

Publication number: US2125686A
Application number: US150817A
Authority: US
Inventors: Norton Albert
Original assignee: Tube Products Ltd
Current assignee: Tube Products Ltd
Priority date: 1936-07-04
Filing date: 1937-06-28
Publication date: 1938-08-02
Anticipated expiration: 1955-08-02
Also published as: GB476755A; FR823676A

Description

Aug, 2, 193.8. A'. NORTON y 2,125,585

l ROLLING MILL Filed June 28, 1937 9 sheets-sheet 1 l ug., 2, 1938. A. NORTON l ROLLING MILL Filed June 28, 1937 9 Sheets-Sheet 2 v Aug; z, 1938. y A NORTON 2,125,686

ROLLING MILL Filed June 28,' 1937 9 Sheets-Sheet 3 Aug. 2, 1938.. A. NRTON 2,125,686

ROLLING MILL Filed Jun 28, 195'? 9 sheets-sheet 4 A, NORTON ROLLING MILL Au@ 2, 193@l Filed June 28, -195'7 9 Sheets-Sheet 5 NORTON ROLLING MILL Filed June 2B, 193'? 9 Sheets-Sheet 6 Aug. z, 193s..

A. NORTON RoLLNG MILL Filed Junge 28, 193'? 9 Sheets-Sheet 7 A. NORTON ROLLING MILL Aug.. 2, 1938.

Filed June 28, 1957 9 Sheets-Sheet 8 A.NORTON ROLLING MILL Aug. 2, 1938.,

9 shets-sheet 9 Filed June 28,` 1937 @Hmmm fir-u Patented Aug. 2, 1938 UNITED STATES lROLLING :MILL

Albert Norton, Birmingham, England, assigner to Tube Products Limited, Oldbury, Birmingham,

England rApplication June 28, 1937, Seri-al No. 150,817 In Great Britain July 4, 1936 l2 Claims.

This invention has for its object to provide an improved machine for effecting reducing operations on metal tubes or rods.

The invention comprises the combination of 5 die rollers forming the pass through which the work piece is to travel, driven supporting rollers which also serve to rotate the die rollers, and means for effecting reciprocatory movements of f the die rollers relatively to the work piece and Vsupporting rollers..

In particular the invention comprises the combination of' die rollers, a reciprocatory carriage on which the die rollers are mounted, driven supporting rollers formed around their -peripheries with alternately arranged working surfaces and ats or the like, andmeans acting on the carriage for imparting rearward movements to the die rollers when they coincide with` the iiats or the like on the supporting rollers, the movements of the die rollers and' carriage in the Iorward direction being effected, when the machine is in operation, by the action ofthe working surfaces of the supporting rollers on the die rollers.

which each is formed with a peripheral groove, the width of -which progressively varies from a narrow part corresponding approximately with the diameter to be produced on the work piece to a relatively wide part corresponding approximately with the 'original diameter of the work piece.

' Also the inventioncomprises a pair of die rollers as above described each of which is pivotally connected at a convenient radial position to one end of a link, and the other end ci each of the two linksl being pivotaliy attached to a spring loaded member, the purpose of the linkage and spring being to maintain the dle rollers in proper co-relationship.

, In the accompanying sheets ofexplanatory drawings- Figures l, 2 and 3 arediagrams illustrating in diiIerent positions tube reducing rollers operat-A ing in accordance -with the invention.

and plan ci a tube-reducing machine embody-l ing my invention. v

Figure 6 is a sectional side elevation and Figure 'I a sectional front elevation of the die rollers, the supporting rollers, and their immediately associated parts, Figure 7 being taken on the line,A.A Figure 4.

' Figure 8 is a sectional end elevation ofthe tube feeding mechanism, this vview being taken Further the invention comprises die rollers of Figures 4 and 5 are respectively side elevationv on the line C.C Figure 9. Figure 9 is a cross section on the line BB Figure 8.

Figure 10 is a part sectional side elevation of a portion of the mechanism situated between the tube reducing rollers and the feeding mecha- 5 nism.

All the views shown in Figures 6 to 10 are Yshown to a larger scale than Figures 4 and 5.

Referring to Figures l to 3 I have there illustrated diagrammatically the supporting and die 10 rollers used'in a machine embodying my invention, for reducing the diameter and thickness of a cold steel or other metal tube. The pass for the tube is formed by a pair of die rollers a. Each'die roller is formed with a circumferential groove. Preferably this groove is made oi vary'- ing width, so that it progressively increases in width from a narrow part which is approximately the same diameter as that to be produced on vthe tube, to a relatively wide part which is of approximately the same diameter as the o'riginal tube. This variation 'oi width is clearly shown in Figure 7. The inactive portion of each die roller which Joins the adjacent ends of the wide and narrow parts of the said groove is formed by a at orrecessed part b. Thetwo die rollers are mounted on a carriage (not shown in Figures 1 to 3) which can reciprocate in the direction ci the axis of the tube. The details of the carriage and the means for holding the two die rollers in the proper working relationship `will be described later.

The die rollers are arranged between a pair of supporting rollers c. These are of lconsiderably larger diameter than the die rollers and are geared together. Also the supporting rollers are driven from any convenient source of motion. On looking at Figures l to 3 (also Figures 6 and 7) it will be seen that the peripheral portion of each roller c which bears on the adjacent die rollera is formed by an alternating succession Y oi parts d, e. Each part d forms a portion of the cylindrical surface oi the roller, and is herein termed the working surface. Each part e, which is made of Aany convenient length and is usually rather greater than the part d, is iiat, or recessed. The die rollers a are free to rotate about their axes on their carriage and are driven by the working surfaces d of the supporting rollers c.

The tube g to be reduced in diameter and wall thickness is supported internally byva mandrel h, this being secured to one end of a rod whichextends backwards through the tube and is attached at its rear end` to the frame of the machine.'

Starting with Figure 1, the die rollers a are shown in the position which they occupy at the beginning of each of the successive reducing actions on the tube, and the forward end of the tube is shown in the reduced condition to which it has been brought by previous actions of the said die rollers. 'I'he initial condition of the tube is shown at the right hand side of the vertical centre line of Figure l, and the finished condition at the left hand side. In the relative positions of the supporting rollers c and the die rollers a shown in Figure 1, a. working surface d on each supporting roller has just entered into engagement with the outer periphery of the adjacent die roller, and the beginning of the working surface of each die roller rests upon the outer original surface of the tube. Due to the rotation of the supporting rollers and the frictional engagement of the parts d of the supporting rollers with the peripheries of the die rollers the latter are not only rotated but are also caused to move laterallyto the left relatively to the stationary tube g, this lateral movement of the die rollers being also transmitted by the die rollers to the carriage on which they are mounted. During this movement the die rollers are, in addition, pressed towards -each other and are caused to exert a squeezing action on the tube for effecting the required reduction of diameter and thickness. The relative positions occupied by the supporting and die rollers at about one half of the length of the travel of the die rollers are shown in Figure 2. This action continues until the parts d of the supporting rollers pass out of contact with the die rollers. 'I'his condition is shown in Figure 3 which shows the relative positions of the supporting and die rollers at the end of the travel oi the die rollers. Immediately afterwards the pressure exerted by the supporting rollers on the die rollers is released, due to the fact that the flats e come adjacent to the die rollers, and consequently the carriage on which the die rollers are mounted is free to be returned quickly to the initial position shown in Figure l, under the action of a spring or weight or other convenient means, the initial position being determined by any conveniently arranged stops. During this movement the die rollers move apart by rolling up the tapered part of the tube. On returning to the initial position shown in Figure 1, the die rollers engage a new part of the tube and immediately thereafter the next parts d of the supporting rollers engage the die rollers and the above described sequence of actions is then repeated. At each action the die rollers engage a small portion of the tube of original diameter, as shown in Figure 1, and reduce it as shown in Figures 2 and 3, and during each return movement of the die rollers a small forward feeding movement is given to the tube so that the die rollers can engage a new part. Preferably a rotational movement ils also given to the tube for the purpose of prev ting formation of, ripples or other arities on the outer surface of the tube. The operation above described is continued until the whole of the tube has been treated.

In the example shown in Figures 1-3, the die rollers rotate through an angle of about 120, the amount of rotation during each lateral movement being dependent on the length of each working part d of the supporting rollers. But the amount of angular movement given to the die rollers may be varied by appropriate alteration of the length of the vparts d.' When it is required to impart a larger angular movement to the die rollers than is shown in Figures 1-3, the length of the parts d on the supporting rollers is correspondingly increased.

By treating tubes in the manner above described I am able to effect large reductions of diameter and thickness in a very rapid and economical manner.

I will now describe a. complete machine embodying my invention. Referring first to Figures 4 and 5 I mount upon a base i a pair of housings k provided with bearings l for the upper and lower supporting rollers c. Between these rollers are arranged the die rollers a which are carried upon a reciprocatory carriage m. The supporting rollers c are interconnected by gear wheels n and one of them is connected to a gear wheel o which is driven by a gear wheel p from any convenient source of motion. At one side of the housings Ic is arranged a horizontal framework q on which is mounted mechanism for imparting longitudinal feeding and rotational movements to the tube. Also there is arranged at the other side of the housings k a mechanism for supporting and rotating the forward end of the tube. It will be convenient to describe separately each of the main functional parts of the machine which are shown assembled in Figures 4 and 5, and this will be done with reference to the drawings shown in Figures 6 to l0.

Referring to Figures 6 and 7, the carriage m on which are mounted the die rollers a is carried on horizontal guide rods r and is freely slidable thereon. The carriage is moved towards the right of Figure 6 by means of a pair of strong springs s. These springs are anchored at their forward ends to the carriage and at their rear ends to the frame q above mentioned. In Figure 6 the carriage is shown for. convenience in its forward position wherein the springs s are extended. As soon as the die rollers a are released by the supporting rollers c the springs s retract the carriage and the die rollers to the position relatively to the rollers c shown in Figure 1. It will be understood that the die rollers a are free to slide 'relatively to each other in the vertical direction on the carriage m, the movement of the die rollers towards each other being effected by the supporting rollers c in the manner above described, and the movement of the die rollers away from each other being effected by their rolling up the tapered part of the tube under the action of the springs s when released by tbe supporting rollers.

To keep the die rollers a. in proper angular relationship with each other I secure to one end of each die roller a radial arm t and to the outer end of each arm I pivotally connect one end of a link u. The other ends of the links u are pivoted to the opposite ends of a cross bar v which at its centre is connected to a spring w anchored to the frame of the machine. During the forward travel of the carriage this spring w is extended and during the return of the carriage the spring w by its action on the rollers a through the parts t, u., v, ensures that the rollers a shall commence each successive squeezing and reducing action in the proper angular relationship shown in Figure 1.

The intermittent feeding forward of the tube is effected by the mechanism shown in detail in Figures 8, 9 and 10. Referring to these figures, and particularly to Figures 8 and 9, there is mounted upon the frame q above-mentioned a carriage 2 which is supported on the frame q by rollers 3 which latter can roll along the upper horizontal side of the frame. On this carriage is` ward end of the screw is supportedby the right mounted a rotatable hollowmember 4 through which can pass the mandrel rod 5 and at the front end of which is mounted a chuck for gripping the rear end of the tubel g. This chuck comprises a split conical gripping piece 6 which can be caused to grip the tube g by the action of an annular wedge 1. This latter is moved into the operative position by an internal bush 8 which is acted on by bell crank levers 9 the latter being movable by i a. sliding sleeve- I which isvactuated by a hand lever II. The hollow body 4 is rotatably supported on the carriage 2 by bearings I2 and it is rotated by 'means of agear wheel I3 secured to the rear end of the said hollow body 4. The gear wheel I3 engages with another gear wheel I4 (Figures 5, 8 and 9) which wheel is in feather-key connection with a longitudinal shaft I for imparting intermittent rotational movements to the tube. Intermittent longitudinal movements are given to thecarriage 2 by a screw I6.

The mandrel rod 5 must be free to rotate with the tube. although it receives no longitudinal movement during the normal working of the machine. To satisfy this-condition the rear end of the rod 5 is anchored to a carriage I 1 supported by rollers I8 on a track 60 at the rear of the frame q.

'Ihe connection between the rod 5 and the cartrack 60. For this purpose a vertical plunger 55` slidably supported in a fixed bracket 56 is adapted at its lower end to pass through an aperture in a cross member 51 of the carriage I1 and enteran aperture in the lower part ofthe bracket 56. A pinion 58 engaging teeth formedin one side of the plunger 55 is adapted to be actuated by a hand wheel 59 to move the plunger into and out of its locking position. o enable the mandrel to be inserted within a n w tube length the carriage I1V is released from the track 65 by appropriate movement of the hand wheel 59 and then moved backwards along the track. After the tube and mandrel have been brought together the carriage is returned to its forward position for the purpose of bringing the forward end of the tube between the die rollers, and is then locked by the plunger 55.

The rotational movement of the shaft l5'and screw I6 is effected by the mechanism shown in Figures 4, 5, `8 and 10. On the driving shaft :I: which carries the pinion p above mentioned there is secured a bevel pinion 6I 'gearing with another bevel pinion 26. 'I'his latter is secured to a short shaft 2l carried by bearings 22, and on one end of this shaft 2l is secured a disc 23 vfrom one side of which extends a roller 24.

The 'roller 24 is adapted to engage` each in succession of a number of radial slot 25 in the disc 26, secured to a shaft 21 arr n ged` in line with one end of the s aft I5 The two shafts 21 and I5 can be couple ogether by a clutch 28 which can be operated by a lever*29. By means of this mechanism the continuous vrotation of the shaft 2| is converted into ,intermit-l canbe adjusted or released by a screwed stem hand bearing 22 shown in Figure 10. To hold the shaft I5 stationaryduring the intervals between the intermittent rotary movements the disc 23 is providedon one side with a disc-like boss 30jiwhich can engage concave recesses formed in the periphery of the disc 26 between the radial notches 25. During the engagement of the roller 24 with a radial groove in the disc 26 the required rotation of the latter is permitted by a'concave recess 3l formed in an appropriate part of the periphery of the boss 30. ATo enable the carriage 2 to return quickly to its rear position the nut 32 which connects the carriage to the screw IiiV is made in two parts which can be separated by a hand lever 33 acting, through a link 34 and lever 35, on any convenient cam mechanism, such as, a rotary disc 64 connected to the lever 35 and having cam slots engaging pins 65 on the parts of the nut 32. f

To support the relativelyslender forward end of the tube I providel the support shown at the left hand side of Figures 4, 5 and 6, and to avoid the imposition of undesirable torsion on the supported, part of the tube the said support is made to rotate at the same rate as the tube.Y Referring to Figure 6 it will be seen that the support comprises` a plurality of friction pieces 36 which bear'upon the exterior of the tube rand form the pas's through which the tube can slide. These friction pieces are carried in a rotatable ring 31 which is supported in a fixed housing 38. The pieces 36 are heldin frictional engagement with the tube by an annular and rotatable wedge piece 39 which is held in its operative y position by a leverv40 which is loaded by a spring p The pressure of the spring on the-lever 49 42 carrying the spring and engaged byan internally -screw threaded hand wheel 43. The intermittent rotation of the ring 31 Vis obtained from the shaft 21 above described. As will be seen in Figures 4 and 10, one end of this shaft has secured to it a bevel pinion 44 engaging another bevel pinion 45 on a shaft 46 and this vlatter transmits its motion through other bevel pinions 41, 49 to a shaft 49 o n which is secured a wheel 50 gearing with a wheel 5I (Figure 5). The wheel 5I is secured to a sprocket wheel 52 whicl'by means of a chain 53 is connected to a sprocket wheel 54 secured to the ring l31 thus imparting a rotational motion to the supporting pieces 36 at the same rate as the rotational motion imparted to the tube.

The support above described also serves an additional purpose. When vthe tube.v undergoing treatment approaches the end of the reducing operation, and can no longer be fed forward by y the mechanism shown in Figure 9, the machine is stopped and the tube is detached from the gripping pieces 6 of the chuck. Another tube to be reduced is then placed on the rod 5 and secured by the said pieces 6, the forward end of this tube being arranged to bear against the short rearl end of `the'tube still in the machine.

The latter tube is fed forward intermittently by-` the pressure of the second, but seeing that it is no longer connected to the chuck gripping pieces 6, it has to be rotated by some other means, and \this function is` performed by the mechanism above described and shown in Figure 6.

The invention is not limited to the example above described as subordinate mechanical details may be varied. Thus instead o f intermittently releasing the die'rollers by arranging flats on the supporting rollers I may provide means acting on the supporting rollers for intermittently releasing their pressure on the die rollers.

Further instead of effecting the return of the die roller carriage by means of a spring as above described it may be returned by a weight, or

b y any convenient lever, cam or other mechanism suitably co-ordinated with the supporting rollers, butin all cases the die rollers are reciprocated relatively to the work piece and the supporting rollers, and their rotational -movements are derived from the supporting rollers. Moreover, the required co-ordination of the die rollers can be effected by lnterengaging gear wheels mounted on the ends of these rollers, though the spring and linkage mechanism above described is preferred on account of its simplicity and convenience.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:-

l. A machine for effecting reducing operations on tubes or rods, comprising the combination of die rollers forming the pass through which the work piece is to travel, driven supporting rollers which also serve to rotate the die rollers and to move them along the work piece, and means for returning the die rollers to their initial positions independently of the 'driven supporting rollers when the latter assume'predetermined positions.

2. A machine for effecting reducing operations on tubes or rods, comprising the combination of die rollers forming the pass through which the work piece is to travel, a reciprocatory carriage on which the die rollers are mounted, driven supporting rollers formed around their peripheries with alternately arranged working surfaces and inactive surfaces` and means acting on the carriage for imparting rearward movements to the die rollers when they coincide with the inactive surfaces on the supporting rollers, the movements of the die rollers and carriage in the forward direction being effected, when thev machine is in operation, by the action of the working surfaces of the supporting rollers on the die rollers.

3. A machine for effecting reducing operations on tubes or rods, comprising the combination of a pair of die rollers forming the pass through which the work piece is to travel, a reciprocatory carriage on which the die rollers are mountedso as to be freely movable towards and away from each other, a pair of driven supporting rollers acting on opposite sides respectively of the die rollers and each formed around its periphery with alternately arranged working surfaces and inactive surfaces, -gearing interconnecting the supporting rollers, means for effecting relative co-ordination of the die rollers, and means acting on the carriage for imparting rearward movements to the die rollers when they coincide with the inactive surfaces on the supporting rollers, the movements of the die rollers and carriage in the forward direction being effected, when the machine is in operation. by .the action of the working surfaces of the supporting rollers on the die rollers.

4. A machine for effecting reducing operations on tubes' or rods, comprising the combination of die rollers each formed with a peripheral groove which varies in width progressively from a narrow part corresponding approximately with the diameter to be produced on the work piece to a relatively wide part corresponding approximately with the original diameter of the work piece, the die rollers being arranged so that their peripheral grooves co-operate to form the pass through which the work piece is to travel, driven supporting rollers which also serve to rotate the die rollers, and means for effecting reciprocatory movements of the die rollers relatively to the work piece and supporting rollers.

5. A machine for effecting reducing operations on tubes or rods, comprising the combination of die rollers each formed with a peripheral groove which varies in width progressively from a narrow part corresponding approximately with the diameter to be produced on the work piece to a relatively wide part corresponding approximately with the original diameter of the work piece, the die rollers being arranged so that their peripheral grooves co-operate to form the pass through which the work piece is to travel, a reciprocatory carriage on which the die rollers are mounted, driven supporting rollers formed around their peripheries with alternately arranged working surfaces and inactive surfaces, and means acting on the carriage for imparting rearward movements to the die rollers when they coincide with the -inactive surfaces on the supporting rollers, the movements of the die rollers and carriage in the forward direction being effected, when the machinev is in operation, by the action of the working surfaces of the supporting rollers on the die rollers.

6. A machine for effecting reducing operations on tubes or rods, comprising the combination of a pair of die rollers each formed with a peripheral groove which varies in width progressively from a narrow part corresponding approximately with the diameter to be produced on the work piece to a relatively widepart corresponding approximately with the original diameter of the work piece, the die rollers being arranged so that their peripheral grooves co-operate to form the pass through which the work piece is to travel, a reciprocatory carriage on which the die rollers are mounted so as to be freely movable towards and away from each other, a pair of driven supporting rollers acting on opposite sides respectively of the die rollers and'each formed around its periphery with alternately arranged working surfaces and inactive surfaces, gearing interconnecting the supporting rollers, means for effecting relative co-ordination of the die rollers, and means acting on the carriage for imparting rearward movements to the die rollers when they coincide with the inactive surfaces on the supporting rollers, the movements of the die rollers and carriage in the forward direction being effected, when the machine is in operation; by the action of the working surfaces oi' the supporting rollers on the die rollers.

'7. A machine for effecting reducing oprations on tubes or rods, comprising the combination of a pair of die rollers each formed with a peripheral groove which varies in width progressively from a narrow part corresponding with the diameter to be produced on the work piece to a relatively wide part corresponding approximately with the original diameter of the work piece, the die rollers being arranged so that their peripheral grooves co-operate to form the pass through which the work piece is to travel, a pair of driven supporting rollers which also serve to rotate the die rollers, v means for effecting reciprocatory movements of the die rollers relatively to the work piece and supporting rollers, a pair of links pivotally connected at their corresponding endsrespectively to the die rollers, these ends being spaced from the axes of the die rollers, and a spring loaded'member pivotally attached to the other end of each link and adapted to cooperate with the links to maintain the die rollers in proper co-relationship.

8. A machine for effecting reducing operations on tubes or rods, comprising the combination of a pair of die rollers each formed 'with a peripheral groove which varies in width progressively from a narrow part corresponding approximately with the diameter to be produced on the Work piece to a relatively wide part corresponding approximately with the original diameter of the work piece, the die rollers being arranged so that their peripheral grooves co-operate to form the pass through which the work piece is to travel, a reciprocatory carriage on which the die rollers are mounted, a pair of links pivotally connected at their corresponding ends respectively to the die rollers, these ends being spaced from the axes of the die rollers, a spring loaded member pivotally attached to the other end of each link and adapted to co-operate with the links to maintain the die rollers in proper co-relationship, a pair of driven supporting rollers formed around their peripheries with alternately arranged working surfaces and inactive surfaces, and means acting on the carriage for imparting rearward movements to the die rollers when they coincide with the inactive surfaces on the supporting rollers, the movements of the die rollers and carriage in the forward direction being effected, when the machine is in operation, against the action of the said spring loaded member by the action of the working surfaces of the supporting rollers on the die rollers.

9. A machine for effecting reducing operations on tubes or rods, comprising the combination of a pair of die rollers each formed with a peripheral groove which varies in width progressively from a narrow part corresponding approximately with the diameter to be produced on the work piece to a relatively widepart corresponding approximately with the original diameter ofthe work piece, the d ie rollers being arranged so that their peripheral grooves co-operate to form the pass through which the. work piece is to travel, a reciprocatory spring loaded carriage on which the die rollers are mounted so as to be freely movable towards and away from each other, a pair of links pivotally connected at their corresponding ends respectively to the die rollers, these ends being spaced from the axes of the die rollers, a

spring loaded member plvotally attached to the other end of each link and adapted to co-operate with the links to maintain the die rollers in proper co-relationship, a pair of driven supporting rollers acting on opposite sides respectively of the die rollers and each formed around its periphery with alternately arranged working surfaces and inactive surfaces, gearing interconnecting the supporting rollers, the movements of the die rollers and carriage in the forward direction being eifected, when the machine is in operation, against the action of the spring loadings by the action of the working surfaces of the supporting rollers on the die rollers, and the rearward movements oi the carriage being effected by the spring loadings.

10. A machine for effecting reducing operations on tubes or rods, comprising the combination of die rollers forming the pass through which the work piece is to travel, a reciprocatory carriage on which the die rollers are mounted, driven supporting rollers formed around their peripheries with alternately arranged working surfaces and inactive surfaces, means acting on the carriage for imparting rearward movements to the die rollers when they coincide with the inactive surfaces on the supporting rollers, the movements of the die rollers and carriage in the forward direction being effected, when the machine is in operation, by the action of the working surfaces of the supporting rollers on the die rollers, a

carriage for the work piece, means for imparting intermittent longitudinal feeding movements to the work piece carriage. a chuck on the work piece carriage for gripping the work piece, and means for imparting rotational movements to the chuck simultaneously with the feeding movements of the Work piece carriage.

11. A machine as claimed in claim 10 and comprising a mandrel-supporting rod, a carriage to which the rear end of the said rod is rotatably connected, and locking means for detachably securing the latter carriage against endwise movement.

12. A machine as claimed i-n claim 10 and comprising a rotational support for the forward end of the work piece, and means for imparting rotational movements to the said support concurrently with therotational movements imparted to the chuck on the work piece carriage.

ALBERT NORTON.