GB2200860A - Bar stock feed device - Google Patents

Abstract

The device comprises a tubular holder 1 externally threaded 3 to receive an adjustable end cap 7 and lock nut 10 and having a fixed attachment 2 at the other end. Various gripping means, e.g. a confronting Spring loaded Frusto-Conical Element 14 with slots, are interchangably accommodated within the tubular holder 1. Alternative gripping elements are sleeves with resilient parts formed by longitudinal or helical slots, or frusto-conical elements with balls for gripping. Sleeve bores or ball arrays are provided for non-circular, e.g. rectangular or hexagonal, cross-section bar stock. <IMAGE>

Description

(54) IMPROVEMENTS RELATING TO FEED FINGERS (71) I, Peter Leslie Windley, a British Subject trading as P & C Machine Tool Services, of Quinton, Birmingham, England do hereby declare the invention for which I pray that a patent may be granted to me, and the method by which it is to be performed to be particularly described in and by the following statement: This invention relates to improved feed devices of the kind commonly used for advancing bar stock in multi-spindle or single spindle automatic lathes or like machines.

Conventional feed devices are made from a steel tube, have a plurality of parallel slots extending along the tube from one end.

The diameter is reduced at that end by closing the slots. Whilst reduced in diameter the tube is heat treated to maintain the reduced diameter. In operation the material is fed through the open large diameter end and forced into the closed diameter end, this provides a friction grip to feed the material by means of a recipricating motion through a collet to an end stop to provide a predetermined portion of material on which work is done. A function of the device is to ensure the portion of material on which work is done is within the length tolerance. In certain circumstances the surface of the material must be free of scores or marks. Master Feed devices of similar construction have separate segmented metal grippers.

An alternative commonly used feed device comprises a tubular body#, a plurality of radially spaced slots in the body, spring means located in the said slots and fixed at one end. The middle portion of the spring means is bowed radially inwardly of the body for engagement with material, adjustment- of spring means by varying the bowing on to the material.

In operation the traditional feed devices have various disadvantages as follows: The grip cannot be adjusted to account for wear or various weights and section of material, only one size and section of material can be used, the feed device is restricted to one machine, too much tension will result in the surface of the material being scratched with straight scores, or spiral scores if high rotational speeds-are involved, too little tension will allow slip and result in a short work portion, this caused wastage of material and affects the life of the speed device. Too much tension will also make the engagement of relatively small section material difficult and in some cases impossible without additional heat treatment to relax the tension. At maximum machine capacity the feeder is weakest and has difficulty holding feedout length, and requires frequent replacement.

The disadvantages of other devices are as follow: When relatively small section material is used the distance between the tubular body and the material surface is increased, the rotational forces acting on spring means will flex or rock the spring means to cause straight or sprial marks on the material surface. The width of spring means will determine the total surface area available for gripping the material.

The present invention relates to improved feed devices which avoids or substantially reduces the disad-vantages of prior art feed devices.

Firstly a holder suitable to accept feed devices will be described followed by a description of each feed device in a configuaration assisting the conventional method of feeding.

The invention accordingly provides a holder suitable for accepting the feed devices as follows: A cylindrical body, having a parallel bore extending from one end and closed at the other end, a reduces diameter extends outwards from the closed end, and a thread is formed on its outside diameter, a bore passes through the closed end and extended portion, an external thread on the opposite end, a plurality of radially drilled holes in the larger diameter. A larger diameter cylinder has an internal bore extending from one end closed at the other, a tapered bore os small diameter through the closed end an internal thread corresponding to that on the cylindrical body, a ring with the outside diameter the same as that of the cylinder and an internal thread corresponding to that on the cylindrical body.

The invention accordingly provides a feed device to fit into the above described holding device and suitable for use in feeding metal or composite elongated material to automatic lathes or like machines, which comprises a cylindrical insert having an external conical taper on one end, a reduced diameter at the opposite end, a profiled bore and a tapered counter bore at the external conical taper end, a plurality of radially spaced longitudinal slots divide the insert into segments. A cylindrical cup having a parallel bore extending from one end to leave a thickness of material at the other end, a reduced bore through this thickness forms an internal lip.A cylindrical taper seat having a conical taper bore, corresponding with that on the cylindrical insert at one end and a reduced external diameter at the other end, a parallel bore extending from the reduced external diameter end and at this same end a tapered counter bore, and a plurality of radially drilled holes. A light spring means located in the cylindrical cup and around the reduced portion of the cylindrical insert, a strong spring means located around and extending from the reduced external diameter on the cylindrical taper seat.

The invention accordingly provides an alternative feed device to fit into the above described holding device and suitable for use in feeding metal or copoisite elongate material to automatic lathes or like machines which comprises a cylindrical insert having an external conical taper, a bore and a tapered counter bore at the conical taper end. A plurality of radially spaced holes in the external conical taper extending through to the bore, each hole containing a ball, roller or like means.

The invention accordingly provides an alternative feed device to fit into the above described holding device and suitable for use in feeding metal or composite elongate material in automatic lathes or like machine which comprises a cylindrical insert having a reduced external middle diameter with small lands at each end, a profiled bore with a tapered counter bore at each end. A plurality of radially spaced slots divide the cylindrical insert into segments. A cylindrical compressive means is contained within the reduced external middle diameter.

The invention accordingly provides an alternative feed device to fit into the above described holding de vice and suitable for use in feeding metal or composite elongated material to automatic lathes or like machines which comprises a tubular insert having a reduced -diameter extending from one end, a bore through this reduced diameter and a tapered counter bore in the outside face of this end. A plurality of radially spaced longitudinal slots parallel or spiral in large diameter portion. Spring members between the slots are deflected radially inwardly to grip the material when positioned in the tubular member.

Embodiments of the Feed Device according to the present invention are now described with reference to the accompanying drawings in which: Fig. 1 is a section along the longitudinal axis according to the first and second embodiment.

Fig. 2 is a section along the longitudinal axis according-to the first and third embodiment.

Fig. 3 is a section along the longitudinal axis according to the third embodiment.

Figs. 4, 5 & 6 are cross sections of the second embodiment showing the types of bore profiles for various bar stock sections.

Fig. 7 is a cross section of the third embodiment showing the arrangement of the straight spring members deflected inwards.

Fig. 8 is an end view of the third embodiment showing the spiral spring members deflected inward to grip hexagon material across the corners.

Fig. 9 & 10 show in diagramatic form respectively two positions in the normal cycle of operation of a typical lathe incorporating the device on to modified standard feed tube and feed finger.

Fig. 11 shows the method of releasing the- taper lock when reverse' movement of the material is necessary.

Fig. 12 is a cross section along the longitudinal axis according to the 1st and 4th embodiment.

Figs. 13, 14, 15, 16 and 17 are cross sections of the 4th embodiment showing the bore profiles and method of gripping various material sections.

Fig. 18 is a section along the longitudinal axis according to the 1st and 5th embodiment.

Figs 19, 20, 21, and 22 are cross sections of the 5th embodiment showing the bore profile and method of gripping various material sections.

Referring to Fig. 1 The holder comprises, the Adapter (1) having an external thread (2) for attachment to the machine feed tube (not shown), an external thread (3), a large bore (4), to accept the feed devices and a small bore (5) through which the material freely passes, radially spaced holes (6) are positioned to provide access for lock release tool (not shown), a Screw Cap (7) with an internal thread (8) to correspond to thread (3), a bore (9) through the end and tapered to provide a lead in for material, a lock ring (10), with an internal thread (21) to correspond with (3) and (8) and which locks theassembly together.

A Spring Cup (12) contains the pad spring (13) and forms a stop at (16) against which the taper seat (15) rests. The Taper Seat (15) has radial holes (18) and by internal rotation the taper seat (15) within the adaptor (1) the holes can be aligned providing access for lock release lever (not shown). An Overfeed spring (16) is located around Taper Seat (15) and when compressed by the Screw Cap (7) forces the Taper Seat (15) against the stop (16) and the Spring Cup (12) against the internal face (18) of adaptor (1). A Pad Spring (13) is contained within the Spring Cup (12). The Taper Pads (14) are located in the Taper Seat (15) and lightly held on the Taper (17) by Pad Spring (13). Spring Cup (12) and Taper Seat (15) are free to rotate within the bore of Adaptor (1).

Figs. 4, 5 & show various types of bore profile (2) to both avoid marking the surface of different sections of material, the contact points (1) can be faced with hard metal, composite or synthetic material to increase life or performance. the gap (5) shows the Taper Pads (6) in the open position gripping the material (4). The closed position is shown in Fig. 1.

Referring to figs. 2 & 3 the Spring Gripper: (1) is an alternative feed device which can be contained in the same holder Fig.1 and using the same Spring (16). The Spring Members (2) are deformed inwards to form a bore (3) slightly smaller than the material (not shown) the material is forced through the bore (3) and the material is gripped by Spring Members (2). The Bore (4) is slightly larger than material diameter and centrally supports the material to prevent excess angular deflection. The Spiral Spring Members Fig.2 (5) will grip the diameter material more efficiently because of the wrap around form, there are no longitudinal edges and in effect, present a cylindrical but flexible gripping bore to the surface of the material. Referring to Fig.8 the cicular profile (3) of Spring Members (2) show the wrap around grip.

Hexagon material is also shown being gripped by the bore on its corners (5) the flats (6) passing through the bore (3) completely free from scoring. Square and other regular section material (not shown) can also be accommodated in a similar manner.

Fig. 7 shows the method of gripping the hexagon material (4-) on the flats (5) using longitudinal Spring Members (2) thus preventing damage to the corners (6). The griping surface of the Spring Member (2) Fig. 7 and Fig. 8 can be faced with hard metal, composite or synthetic material to increase the life of performace. Relatively small diameter material can be accommodated by using small grippers held in reducing sets (not shown).

Referring to Fig.12 the cylindrical insert (31) and balls (32) is an alternative device which can be contained within the same holder Fig.1 using the same spring clip (12) Pad Spring (13)Taper Seal (15) and Necked Spring (16). The ball (32) is contained within the radially spaced holes (37) and has means to prevent balls (32) from falling into bore (33) or out of taper (38) but allow the ball (32) to freely rotate within the hole (37).

Figs. 13, 14, 15, 16, and 17 show different configurations of balls (32) and profiles (3) to allow balls (32) to grip varying sections of material (4).

Referring to Fig. 18 the cylindrical insert (41) and spring means (42) is an alternative device which can be contained within the same holder -Fig.1 using the same overhead spring (16).

Figs. 19, 20, 21, 22 show different types of Bore Profile (3) to grip the various sections of material (3).

Reference is now made to the cycle operation illustrated in Figs.

9 and 10. The material (7) is fed into the feed device until it comes into contact with lead-in (8) in the position this Pad Spring (18) is forcing the Taper Pads (1) into the Taper (2) of the Taper Seat (15) but unable to overcome the stronger overfeed#spring (17). Further movement of the material (7) forces the Taper (2) of Pad (1) out of the Taper (2) on Taper Seat (15) to compress Pad Spring (18), the slots (19) Fig.1 will open and allow the material to pass into Bore (6). The material is fed through with very slight frictional resistance to a position (50). At this point and in this condition a feed stroke takes place towards the machine stop (51).

Immediately this movement takes place, the friction of the pads (1) assisted by pressure of Pad Spring (18) pushes the Taper (2) of Pad (1) into the Taper (2) of Taper Seat (15). The wedge effect formed by the contact between Taper (2) and material (7) locks Pad (1) on the material (7). The force required to feed the material (7) is not sufficient to overcome the overfeed spring (17), therefore the material is immediately fed out until the end of the material (7) comes into contact with the machine stop (51). To ensure that the end of the material (7) does not bounce back from the machine stop (51), due to its inertia, a further small movement of the feed device is made. The Pads and Taper Seat cannot move further forward due to the locking effect of the Taper (2).

Referring to Fig.10 further movement of the device takes place and the force on the Taper (2) is increased to force the Taper Seat (15) away from the contact point (16) and Cup (12) against the overfeed Spring (17) and holding the end of material (7) firmly against the Machieb Stop (51). The Machine carries out operation on the material feed out, this portion is then parted off and the feed device returns to carry out another feed stroke and the cycle is continually repeated.

It is necessary at times to be able to feed the material in the opposite direction and a facility for achieving this is described as follows: Referring to Fig.ll this operation is carried out with the feed device in the position illustrated in Fig.9, by rotating the Pads (1) and Taper Seat (15) within the Adaptor (19), the holes (20 & 21) are aligned, a suitable took (52) is placed through the holes to engage the rear edge of the Taper Pads (1), using the Tool (52) as a lever pressure is applied to release the contact between Taper (2) of Pad (1) and Taper (2) of Taper Seat (15) against light pressure of Pad Spring (18) and bore (6) is opened to allow the material (7) to be pushed through the Pad (1) in reverse direction.

Referring to Fig.18 the insert (41) and Spring Means (42) is contained within the holder Fig.1. Before material is engaged the force exerted by the Spring Means (42) closes the segments Fig.18 (2) reducing the bore (46) smaller than the material. Engagement of material into bore (46) forces the segments outward against the pressure of the Spring Means (42) and gripping the material within the bore sufficient to move material in the required direction during the feed stroke. The gripping force is overcome when the holder is returned to rest position ready for another feed stroke.

Referring to ig.12 reference is now made to the basic cycle of operation illustrated in Figs. 9 and 10. Replacing the engagement of material into Pad (1) with the engagement into Insert (31) the material is entered into the Insert Bore (33) of Insert (31) until it makes contact with the balls (32) at point (36) until the material is located within them with virtually no friction. At this point and in this condition a feed stroke takes place. Immediately this movement takes place the friction of the balls (32) assisted by the Pad Spring (18) pushes the Balls (32) into the Taper (17). The wedge effect formed by the contact between the Taper (17) and the balls (32) at point (36) locks the Ball (32) on to the material. The cycle of operation continues as described in Figs 9 & 10.

The above described devices can be used in the conventional feed finger position or otherwise used when contained within a suitable holder.

I CLAIM FOR MY INVENTION 1 A feed device suitable for use in feeding metal bar or like elongate article to an automatic machine tool which comprises a holder suitable for containing gripping devices for use in feeding elongate material to an automatic lathe or like machine which comprises.

a tubular housing to be mounted on the feed element of the machine and providing an internal cylindrical surface ith a fixed attachment at one end, an adjustable attachment the opposite end and means to lock the said adjustable attachment with said tubular housing.

2 A feed gripper suitable to be contained In Fig.1 and for use in feeding elongate material to an automatic lathe or like machine, which comprises a segmented sleeve having a parallel bore capable of opening and closing and of receiving said elongate material within the bore with minimum friction and capable when closed of gripping said elongate material, having an external conical form, an outer tubular member having an internal conical form corresponding to that of the segmented sleeve and into which the said segmented sleeve is received, the resulting interaction of which limits the movement of the segmented sleeve in one direction and frees movement of the segmented sleeve in the other direction.

3 A feed gripper suitable to be contained in Fig. 1 and for use in feeding elongate material to an automatic lathe or like machine, which comprises a tubular member, the middle portion having a plurality of radially spaced slots parallel with its central axis, the so formed adjacent members being deflected radially inwardly to grip the elongate material.

4 A feed device suitable to be contained in Fig.1 and for use in feeding elongate material to an automatic lathe or like machine which comprises a tubular member, the middle portion having a plurality of radially spaced longitudinal spiral slots the so formed adjacent members being deflected radially inwardly to grip the elongate material.

5 A feed gripper suitable to be contained in Fig.1 and for use in feeding elongate material to an automatic lathe or like machine which comprises a tubular member having a plurality of radially spaced drilled holes containing balls or like means free to rotate or move within the holes, having a bore formed by the inner surface of the balls or like means capable of receiving the said elongate material. An outer tubular member having an internal conical form. The resultant interaction between the outer tubular member, the balls or like means and the material limits the movement of the balls or like means in one direction and frees the movement in the said direction.

6 A feed gripper suitable to be contained in Fig.1 and for use in feeding elongate material to an automatic lathe or like machine which comprises a segmented tubular member, a spring means around the outer longitudinal surface of the segmented tubular member which deflects the segments inwardly to grip the elongate material when placed within the bore.

7 A holder according to Claim 1 having an external adjusting screw and lock ring, herein described and as shown in Fig.1.

8 & A holder according to Claim 1 having a thread to facilitate conventional attachment to a feed tube.

9 A feed device according to Claim 2 having a spring means to apply pressure to segmented sleeve.

10 A feed device according to Claim 2 having a spring means to apply pressure to assembly.

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

Claims (16)

**WARNING** start of CLMS field may overlap end of DESC **. The above described devices can be used in the conventional feed finger position or otherwise used when contained within a suitable holder. I CLAIM FOR MY INVENTION

1 A feed device suitable for use in feeding metal bar or like elongate article to an automatic machine tool which comprises a holder suitable for containing gripping devices for use in feeding elongate material to an automatic lathe or like machine which comprises.

a tubular housing to be mounted on the feed element of the machine and providing an internal cylindrical surface ith a fixed attachment at one end, an adjustable attachment the opposite end and means to lock the said adjustable attachment with said tubular housing.

2 A feed gripper suitable to be contained In Fig.1 and for use in feeding elongate material to an automatic lathe or like machine, which comprises a segmented sleeve having a parallel bore capable of opening and closing and of receiving said elongate material within the bore with minimum friction and capable when closed of gripping said elongate material, having an external conical form, an outer tubular member having an internal conical form corresponding to that of the segmented sleeve and into which the said segmented sleeve is received, the resulting interaction of which limits the movement of the segmented sleeve in one direction and frees movement of the segmented sleeve in the other direction.

3 A feed gripper suitable to be contained in Fig. 1 and for use in feeding elongate material to an automatic lathe or like machine, which comprises a tubular member, the middle portion having a plurality of radially spaced slots parallel with its central axis, the so formed adjacent members being deflected radially inwardly to grip the elongate material.

4 A feed device suitable to be contained in Fig.1 and for use in feeding elongate material to an automatic lathe or like machine which comprises a tubular member, the middle portion having a plurality of radially spaced longitudinal spiral slots the so formed adjacent members being deflected radially inwardly to grip the elongate material.

5 A feed gripper suitable to be contained in Fig.1 and for use in feeding elongate material to an automatic lathe or like machine which comprises a tubular member having a plurality of radially spaced drilled holes containing balls or like means free to rotate or move within the holes, having a bore formed by the inner surface of the balls or like means capable of receiving the said elongate material. An outer tubular member having an internal conical form. The resultant interaction between the outer tubular member, the balls or like means and the material limits the movement of the balls or like means in one direction and frees the movement in the said direction.

6 A feed gripper suitable to be contained in Fig.1 and for use in feeding elongate material to an automatic lathe or like machine which comprises a segmented tubular member, a spring means around the outer longitudinal surface of the segmented tubular member which deflects the segments inwardly to grip the elongate material when placed within the bore.

7 A holder according to Claim 1 having an external adjusting screw and lock ring, herein described and as shown in Fig.1.

8 & A holder according to Claim 1 having a thread to facilitate conventional attachment to a feed tube.

9 A feed device according to Claim 2 having a spring means to apply pressure to segmented sleeve.

10 A feed device according to Claim 2 having a spring means to apply pressure to assembly.

11 A feed device according to Claim 2 having radial holes

providing a means for the lock release function.

12 A feed device according to Claim 2 having a bore Fig.s 3 & 4 slightly larger than material diameter to form a support bush.

13 A feed device according to Claim 3 having a bore in the reduced diameter -portion slightly larger than the material diameter to form a support bush.

14 A feed device accordig the Claims 2 & 3, having means to facilitate the use of smaller size inserts herein described.

15 A feed device according to Claim 4, having radial holes containing balls or rollers to provide the gripping action.

16 A feed device substantially as herein described with reference to the accompanying drawing.