US2311368A

US2311368A - Means for transforming rotary to reciprocatory motion as applied to cutting machines

Info

Publication number: US2311368A
Application number: US384768A
Authority: US
Inventors: Cito Camillo
Original assignee: Individual
Current assignee: Individual
Priority date: 1940-04-04
Filing date: 1941-03-22
Publication date: 1943-02-16
Anticipated expiration: 1960-02-16

Description

Feb. 16, 1943.

.c.c|1'o 2,311,368 MEANS FOR TRANSFORMING A ROTARY TO A RECIPROCATORY MOTION AS APPLIED TO CUTTING MACHINES Filed March 22, 18:41 2 Sheets-Sheet 1 MEANS FOR TRANSFORMING A ROTARY TO A RECIPROCATORY Feb. 16,- 1943. c ClTO 1,368

MOTION AS APPLIED TO CUTTING MACHINES Filed March 22, 1941 2 Sheets-Sheet 2 W 56 155 I 54 6 I l 5O 46 55 5 24 28 20 F; 48- 2-7 CamL ZZo CdZo I71 1 672 for:

' the tool holder.

for acheiving them will now be claimed.

lines a shearing tion.

Patented Feb. 16, 1943 UN [TED "STATES PATENT OFFICE MEANS FOR TRANSFORMING 'ROTAR'Y TO RECIPR OCATORY MOTION AS APPLIED T CUTTIN G MACHINES 1 CamilloCito, Ucclc-Brussels, Belgium; vestedin the Alien Property Oustodian v App1ioati0n'March 22, 1941, Serial No. 384,768 I In Belgium April 4, 1940 I Claims. (01. 164-47) Mechanisms of this'kind are known in which a:'.

roller is carried by the piece to be moved and receives the push of the disc which is excentrically mounted relatively to its axis of rotation or is provided with a cam at its periphery.

In the known mechanisms the shaft of the 'roll 1 er, the dimensions of which are relatively small,

' has to sustain the-impact due to the engagement of the disc with the roller'which results in relatively rapid damage of this shaft.

The primary object oi the present invention isto provide a mechanism which does not present this disadvantage.

According to the inventi0n,'said rolling member is freely mounted between the periphery of the disc and a guide concentric to the latter, in

the median part of which the tool holder toibe moved with an alternating movement penetrates, said roHing member pushing back' said holder when it is carried round between said holder and the disc, and means being provided for restoring the rolling member to normal position aftereach actuation of the tool holder.

According to an advantageous embodiment, the speed of rotation of the disc is sufi'icient to impart to the rolling member a speed such that after having pushed back thetool'holder, it may roll back into a position wherein it may again'be forced away by thedisc between the latterand In this case, the speed of rotation constitutes the means for restoring the rolling member to its working position every time after it has pushed back the reciprocatory tool holder.

Other objects of the'invention and'mechanisms The drawings accompanying the present spedescribed and cification show schematically and by way ofjexample only, shears according to the invention comprising the aforesaid mechanism for transforming a continuous movement of rotation'into an alternating movement-of translation.

Figure 1 shows by means of some schematic machine according to the invention, the upper part of I Figure 2 shows in perspective, in vertical secthe 'shearingmachines shownin Figure 1.

Figure 3 is a perspective-view, with breaking away of some parts, of'thelower-part-ofthe shearing'machine sho'wn-inFigure 1.

Figure 4 is a'view onan enlargedscale and partly in section of a portion of Figure 1.

In these various figures,- the same references apply to identical elements. Y The shr ars'shown in Figure l,-comprise-adisc 2 keyed on an horizontal shaft"?! Which rotates in the direction ofthe arrow? X at great speed,

for example at approximately WOO-revolutions per minute. A roller {is-freely mounted between the periphery of this'disc and aguide 5 concentrical to the latter. -This guide Bis constituted by two flanges '6 and I (Figures 2)-which aresecured to the disc 2 by securing means diagrammatically shown at 8.

v Between the flanges-6 and'lpenetrates an arm 9 pivoting at lfl andsurmounting a rod I'I car'rying the tool, this rod being permanently urgedby a spring I2 (Figure IltoocCUPy a position in which the pivoting'arm 9 is in the path 'of' the roller d-zwhen the latter is carried around between the disc 2 and the concentric guide 5.

When during this displacementof" the roller 4, the latter comes incontact with the pivoting-arm 9, if the angle that the latter-makes with thedisc is sufiiciently small, it pushes back thisarm against the spring l2. This angle-depen'dson the between the bodies in concoefiicient of' friction tact.

For machined pieces in steel, thean'gle adopted is, for example, 6 if the disc'Z has a diameter of millimeters and the roller 4 adiameter of 12 millimeters.

fAssoonas the roller 4 is beyond the position overlying the rod 1 I, the latter goes up under the action of spring l2. If-the rod H holds-acutter '31, during its lowering-it shears a piece to be sheared such as a wire"l4-disposed under this cutter.

necessary, to render possible a new shearing; that said rollingmember be broughtbackintoa posie tion in which it is ready to work, such as th'e position in which it is shown.

Thetwo flanges 6- and l secured to the disc 2 have inwardly 'facingiedges i5. The peripheral part of i the disc possesses moreover two grooves symmetrically situated relatively to the median plane of the disc. One of these grooves is shown In order that each shearing operation may be;

controlled at will, there is provided a device for stopping the roller 4 on the path followed by the latter, in advance of the plates where the pivotthe end of the wire-i4 comes in contact with a rod 40 (Figures 1 and 3) guided in bearings 4|.

This rod carries a catch 42 adjustable thereon.

A spring 43 is interposed between said catch and an armbf a crank lever 44 connected to a rod 45 which at its other end is connected to the ing arm 9 is situated on said path, this stopping device being so mounted that it may liberate the roller 4 at the desired moment.

The stop-ping device shown is situated at the level of the axis of rotation .of..thedisc2.t It is constituted by a rotatable star l8 onebr'anch l9v of which is maintained across the path of the rolling member when a movable stop 29 is in a position which prevents the star'fromrotating.

The various branches of the latter are angularly spaced one from the other by an angle such that when the star rotates for permitting the roller 4 to pass, another branch immediately comes across the path of the roller in order to stop the latter after the disc has forced it to make a revolution.

The movable stop 29 isiconstituted by one of the arms of a crank lever 21-, a second; arm 22of which is so disposed that when the pivoting movement which causes the liberation of the star is continued, this second arm obliges said star to rotate after its liberation, by a face 23 on the arm 22 striking against the rear face 24 of one of the branches of the star. I In the position that it then occupies the arm 22 stops theimovement of rotation of the star that it has produced, its face serving as abutment against the front face 25 of the following branch. i

The secondarm 22 of the cranklever 2| ;is at such an angle to the first arm that when the crank lever 2| is broughtback to its initial position, it does not leave the star branchwhose front face 23 is in abutment with it, until the first arm 20 isagain in a position in, which it prevents rotation of the star.

In order to prevent a movement oi rotation of gthe star 18 in the direction oppositeto that which releases the roller 4, this star is secured to a:

ratchet wheel 21 which cooperates with a pawl 28 permanently maintained engaged by a spring 29. The movable stop 28 is permanently urged towards the position for which it stops the star [8 under the action of a spring 39 acting on an arm 31 of a lever 32 fixed on the pivot 33 of the crank lever 2 l a In order to prevent a too violent shock of the roller 4 on the branch of the star l8 which retains this roller when it is brought back into the position shown, there is provided a device for braking this roller constituted by an arm 34 oscillating around a pivot 35. This arm is permanently urged under the action of its weight to occupy a position in the path of the roller. It is however maintained somewhat spaced from the rotatable disc 2 by an abutment 36. The position occupied by the arm 34 has moreover the effect of preventing the roller 4 from rebounding from the branch l9 of the star to the position itoccupied' on leaving the pivoting arm 9.

c The shears shown in Figure 1 are constructed in such a manner that they automatically shear the wire I 4 as soon as the latter haspassed over the desired length beyond the tool or cutter 3'l 75 lever 32. I

The lever 44 and consequently the rod 40 are permanently urged by a spring 46 towards a position for which the movable stop 20 stops the star 18 in'the position for which it retains the roller 4. The spring 43 possesses a stiffness such that rollers 41 (Figure 1).

It is however to be noted that when disc 2 rotates at great speed, the shearing is practically instantaneous from the moment the movable stop 28 liberates the star 18. r

In order that the portion to-be sheared from the wire [4 shall come in contact with the extremity of the rod 49, even when the wire is of small diameter, the guide 39 possesses a bottom 48 (Figures 1, 3 and 4). But at the moment when the shearing isefiected, the sheared portion must be instantaneously evacuated in order to immediately permit the introduction of another wire length into the guide39. For this reason the ment by the displacement of the .pivoting arm 9 which is displaced at the same time as the rod ll holding the tool 31. The mechanical connection provided between the bottom 48 and the pivoting arm 9 comprises, for example, a rod 49 (Figures 1, 2 and 4) connected, on the one hand,

to a projection 50 of the arm 9 and, on the other hand, to one arm 5| of a crank lever 52 keyed on a shaft 53. on the latter, are keyed two bars 54 (Figure 4) and 55 (Figure 3) on which the bottom 48 is secured. 7

As may be easily seen on Figures 1 and 4, the lowering of arm 9 at the moment of the shearing of the wire I4 causes the displacement of the rod 49 in the direction of the arrow Y andQconsequently, the pivoting of the crank lever 52 and of the shaft 53 inthe direction of the arrow Z. This pivotal movement removes the bottom 48 away from the guide 39 and, consequently, causes the fall of the wire portions just sheared.

In order to prevent the bottom 48 from returning too rapidly against the guide 39 under the action of the sudden raising of the pivoting arm 9 caused by the spring I2, the rod 49 is not rigidly connected to the arm 5! of the crank lever 52. The rod 49 freely slides in an aperture provided in a sleeve 56 which pivots at the extremity of the arm 5|. A nut 51. of adjustable position on the rod 49 abuts against the exterior face of this moved in the reverse direction, it freely slides in the sleeve 55 without causingjthebottom 48 to approach the guide 39.

This approach is effected by a'mechanism put under tension during the shearing and acting more slowly on the bottom than the rod carrying the tool 39 would have done it when rising under the action of spring I2. This mechanism is constituted by a dash-pot comprising a cylinder 58 (Figures 1 and 4) in which is mounted a piston 59, the rod of which is connected to the crank lever 52 (Figure 4.)

When the crank lever 52 pivots in the direction of the arrow Z, a spring BI is compressed the elongation of which causes the closingof the bottom 48. The elongation speed of this spring is adjusted by the position of a screw 62 whose point engages an orifice 63 through which the air contained in the cylinder 58 behind the piston 59 escapes during the closing of the bottom.

It is evident that the invention is not exclusively limited to the embodiment shown.

What I claim is:

1. Guillotine shears, comprising a rotating disc, a guide concentric to said rotating disc, a rolling member freely mounted between the periphery of the disc and the guide, a tool holder penetrating into said guide sufficiently close to the periphery of the disc to be reciprocated by the rolling member when the latter is carried round by the disc, and means for permanently urging said tool holder towards said disc, the speed of rotation of the disc being sulficient to impart to the rolling member a speed such that after having actuated said tool holder,

it returns to a position to repeat the actuation.

2. Guillotine shears, comprising a rotating disc, flanges secured to the latter at its periphery and having edges directed one towards the other, a rolling member freely mounted between the periphery of the disc and said edges, a tool holder penetrating between said edges sufficiently close to the periphery of the disc to be reciprocated by the rolling member when the latter is carried round by the disc between the same and said holder, means for permanently urging said tool holder towards said disc, and means for returning the rolling member to normal position after it has actuated said tool holder.

3. Guillotine shears, comprising a rotating disc with a horizontal axis of rotation, flanges secured to said disc at its periphery and having edges directed one towards the other, said disc having grooves parallel to its median plane and between the periphery of the disc and the flanges, a roller freely mounted between the periphery of the disc and said edges with its axis of rotation parallel to the axis of rotation of the disc said roller having peripheral flanges engaged in said grooves, a tool holder penetrating between said edges sufficiently close to the periphery of the disc to be reciprocated by the roller when the latter is carried round by the disc between the same and said holder, means for permanently urging said holder towards said disc, and means for restoring the rolling member to normal position after it has actuated said tool holder.

4. Guillotine shears, comprising a rotating disc, a guide concentric to said rotating disc, a rolling member freely mounted between the periphery of the disc and the guide, a tool holder penetrating into said guide sufficieintly close to the periphery of the disc to be reciprocated by therolling member when the latter is carried round by for-permanently urging said holdertowardssaid disc, means for restoring'the rolling member to normal position after it has actuated said-tool holder, a rotating star with several branches movable into the path of the rolling member when the star rotates said branches being spaced by an angle such that when the star rotates to release the rolling member another branch immediately comes into the path of the rolling member to stop the latter after it has completed a revolution, and a movable stop for stopping said periphery of the disc to be reciprocatedby' the the disc between the same and said holder, means rolling member when the latter is carried round by the disc between the same and said holder, means for permanently urging said holder towards said disc, means for restoring the rolling member to normal position after it has actuated said holder, a rotating star with several branches movable into the pathof the rolling member when the star rotates said branches being spaced by an angle such that when the star rotates to release the rolling member another branch immediately comes into the path of the rolling member to stop the latter after it has completed a revolution, a movable stop for stopping said star with one of its branches in the path of-the rolling member, and a crank lever having one arm serving as abutment for one of the branches of the star and a second arm operative to further rotate the star upon continued rotation of the crank lever after said release and then to stop the rotation of the star by engaging the front face of the following branch.

6. Guillotine shears, comprising a rotating disc, a guide concentric to said rotating disc, a rolling member freely mounted between the periphery of the disc and the guide, a tool holder penetrating into said guide sufficiently close to the periphery of the disc to be reciprocated by the rolling member when the latter is carried round by the disc between said disc and said holder, means for permanently urging said holder towards said disc, means for restoring the rolling member to normal position after it has actuated said holder, a rotating star with several branches movable into the path of the rolling member when the star rotates and spaced by an angle such that when the star rotates to release the rolling member, another branch immediately comes into the path of the rolling member. to stop the latter after it has completed a revolution, a movable stop for stopping said star with one of its branches in the path of the rolling member, and a crank lever having one arm serving as abut ment for one of the branches of the star and a second arm operative to further rotate the star upon continued rotation of the crank lever after said release and then to stop the rotation of the star by engaging the front face of the following branch, the second arm of this crank lever being at such an angle to the first one that when the crank lever returns to initial position, it remains engaged with the frontface of one branch of the star until the first arm of the same crank lever returns to a position wherein it prevents rotation of the star.

7. Guillotine shears, comprising a rotatingdisc, 'aguide concentric to said rotatingdisc, a'rolling of the disc and the guide, a tool holder'penetrating into said guide sufiiciently close to the periphery of the disc to be reciprocated by the rolling member when the latter is carried round by the disc between said disc and said holder, means for permanently-urging said holder toand a pawl cooperating with said ratchet wheel in order to prevent back turning of the star.

8. Guillotine shears, comprising a rotating disc, a guide concentric to said rotating disc, a rolling member freely mounted between the periphery ,of the disc and the guide, a tool holder penetrating into said guide suihciently close to the periphery of the disc to be reciprocated by the rolling member when the latter is carried around by the disc between said disc and said holder, means for permanently urging said holder towards said disc, means for restoring the rolling member to its norma1 position after it has actuated said holder, a rotating star with several branches movable into the path of the rolling member when the star rotates and spaced by an angle such that when the star rotates to release the rolling member another branch immediately comes into the path of the rolling member to stop the latter after it has completed a revolution, a movable stop for stopping said star with one of its branches in the path of the rolling member, and means for permanently urging said movable stop towards star arresting position.

9. Guillotine shears, comprising a rotating disc, a guide concentric to said rotating disc, a rolling member freely mounted between the periphery of the disc and the guide, a tool holder penetrating into said guide sufficiently close to the periphery of the disc to be reciprocated by the rolling member when the latter is carried .round by the disc between said disc and said holder, means for permanently urging said holder towards said disc, means for restoring the rolling member to normal position after it has actuated said holder, means for arresting the rolling member in its path in advance of the place of encounter with said tool holder, said means being adapted to release the rolling member, and means for braking the rolling member in advance of the arresting means.

10. Guillotine shears, comprising a rotating disc, a guide concentric to said rotating disc, a rolling member freely mounted between th periphery of the disc and the guide, a tool holder penetrating into said guide sufiiciently close to the periphery of the disc to be reciprocated by the rolling member when the latter is carried round by the disc between said disc and said holder, means for permanently urging said holder towards said disc, means for restoring the rolling member to normal position after it has actuated said holder, means for arresting the rolling member in its path in advance of the place of encounter with said tool holder, said means being adapted to release the rolling member, an

I -member freelymounted betweenthe periphery I oscillating arm disposed on the path of the rolling member in advance of the arresting means,

means for permanently urging said oscillating arm towards said path, and means for maintaining said oscillating arm at a short distance from the rotating disc.

11. Guillotine shears, comprising a rotating disc, a guide concentric to said disc, a rolling member freely mounted between the periphery of the disc and the guide, a tool holder penetrating into said guide sufiiciently close to the periphery of the disc to be reciprocated by the rolling member when the latter is carried round 7 by the disc between said'disc and said tool holder,

means for permanently urging said tool holder towards said disc, means for restoring the rolling member to normal position after it has actuated said tool holder, means for arresting the rolling member in its path in advance of the place of encounter with the tool holder said means being adapted to release the rolling member, a stop arranged to be pushed back by the object to be sheared when the latter extends beyond the tool for the desired length, and means for releasing the rolling member between said stop and said arresting means, said release means being actuated by said stop.

12. Guillotine shears, comprising a rotating disc, a guide concentric to said disc, a rolling member freely mounted between the periphery of the disc and the guide, a tool holder penetrating into said guide sufficiently close to the periphery of the disc to be reciprocated by the rolling member when the latter is carried round by the disc between said disc and said tool holder, means for permanently urging said tool holder towards said disc, means for restoring the rolling member to normal position after it has actuated said tool holder, means for arresting the rolling member in'its path, in advance of the place of encounter with the tool holder, said arresting means being adapted to release the rolling member, a stop arranged to be pushed back by the object to be sheared when the latter extends beyond the tool for the desired length, and a mechanical connection between said stop and said arresting means such that when said stop is pushed back by the object to be sheared it produces the release of the rolling member.

13. Guillotine shears, comprising a rotating disc, a guide concentric to said disc, a rolling member freely mounted between the periphery of the disc and the guide, a tool holder penetrating into said guide sufiiciently close to the periphery of the disc to be reciprocated by the rolling member when the latter is carried round by the disc between said disc and said tool holder, means for permanently urging said tool holder towards said disc, means for restoring the rolling member to normal position after it has actuated said tool holder, means for arresting the rolling member in its path in advance of the place of encounter with the tool holder, said means being adapted to release the rolling member, a stop arranged to be pushed back by the object to be sheared when the latter extends beyond the tool for the desired length, means between said stop and said stopping device such that when said stop is pushed back by the object to be sheared it produces release of the rolling member, and a device for adjusting the instant of release of the rolling member in relation to the position of the stop, interposed between the latter and the means for arresting the rolling member.

14.:Guillotin'e shears; comprisingv a rotating disc, a guide concentricto said discya'rollin-g member freely mounted between the periphery of said tool holder, means for arresting the rolling member inrits path in advance of the place of encounter with the tool holder, said means being adapted to release the rollingmember, a rod arranged to be pushed back by the object to be sheared when the latter extends beyond the tool for a desired length, a catch of adjustable position on said rod, and a mechanical connection between said catch and said arresting means such that when said catch is pushed back with said red by the object to be sheared it produces release of the rolling member.

15. Guillotine shears, comprising a rotating disc, a guide concentric to said disc, a rolling member freely mounted between the periphery of the disc and the guide, a tool holder penetrating into said guide sufiiciently close to the periphery of the disc to be reciprocated by the rolling member when the latter is carried round by the disc between said disc and said tool holder, means for permanently urging said tool holder towards said disc, means for restoring the rolling member to normal position after it has actuated said tool holder, means for arresting the rolling member in its path in advance of the place of encounter with the tool holder, said means being adapted to release the rolling member, a stop arranged to be pushed back by the object to be sheared when the latter extends beyond the tool for the desired length, means between said stop and said arresting means such that when said stop is pushed back by the object to be sheared it produces release of the rolling member, and means for permanently urging said stop towards a position in which it leaves said arresting means in arresting position.

16. Guillotine shears, comprising a rotating disc, a guide concentric to said disc, a rolling member freely mounted between the periphery of the disc and the guide, a tool holder penetrating into said guide suinciently close to the periphery of the disc to be reciprocated by the rolling member when the latter is carried round by the disc between said disc and said tool holder, means for permanently urging said tool holder towards said disc, means for restoring the rolling member to normal position after it has actuated said tool holder, means for arresting the rolling member in its path in advance of the place of encounter with the tool holder said means being adapted to release the rolling member, a stop arranged to be pushed back by the object to be sheared when the latter extends beyond the tool for the desired length, means between said stop and said arresting means such that when said stop is pushed back by the object to be sheared it produces release of the rolling member, a guide for the piece to be sheared beyond the tool, a removable bottom for said guide, and means for removing said bottom after a shearing operation said means being controlled by said operation.

17. Guillotine shears, comprising a rotating disc, a guide concentric tosaid disc, a rolling member freely mounted between the periphery of the disc andtheguide, a tool holder penetrating into said guide sufiiciently close to. the periphery of the disc to be reciprocated by the rolling member when the latter is carried round by the disc between said disc andsaid tool holder, means for permanently urging said tool holder towards said disc, means for restorin the rolling member to normal position after it has actuated said tool holder, means for arresting the rolling member in its path inadvance of the place of encounter with the tool holder said means being adaptedto release the rolling member, a stop arranged to be pushed back by the object to be sheared when the latter extends beyond the tool for the desired length, means between said stop and said arresting means such'that when said stop is pushed back by: the object to be sheared it produces release of the rolling member, alguide :for the piece, to be sheared beyond thev tool, a removable bottom for said guide, and a mechanical connection between said bottom and said tool holder whereby the bottom is removed during the shearing operation.

18. Guillotine shears, comprising a rotating disc, a guide concentric to said disc, a rolling member freely mounted between the periphery of the disc and the guide, a tool holder penetrating into said guide sufficiently close to the periphery of the disc to be reciprocated by the rolling member when the latter is carried round by the disc between said disc and said tool holder, means for permanently urging said tool holder towards said disc, means for restoring the rolling member to normal position after it has actuated said tool holder, means for arresting the rolling member in its path in advance of the place of encounter with the tool holder, said means being adapted to release the rolling member, a stop arranged to be pushed back by the object to be sheared when the latter extends beyond the tool for the desired length, means between said stop and said arresting means such that when said stop is pushed back by the object to be sheared it produces release of the rolling member, a guide for the object to be sheared beyond the tool, a removable bottom for said guide, a mechanical connection between said tool holder and said bottom for positively opening said bottom during the shearing operation, means enabling said mechanical connection to efiect its return stroke during the return stroke of the tool holder without closing the bottom, and a mechanism put under tension during the shearing operation for closing the bottom more slowly than said mechanical connection.

19. Guillotine shears, comprising a rotating disc, a guide concentric to said disc, a rolling member freely mounted between the periphery of the disc and the guide, a tool holder penetrating into said guide sufficiently close to the periphery of the disc to be reciprocated by the rolling member when the latter is carried round by the disc between said disc and said tool holder, means for permanently urging said tool holder towards said disc, means for restoring the rolling member to normal position after it has actuated said tool holder, means for arresting the rolling member in its path in advance of the place of encounter with the tool holder, said means being adapted to release the rolling member, a stop arranged to be pushed back by the object to be sheared when the latter extends beyond the tool for the desired length, means between said stop and said arresting means such that when said stop is pushed back by the object to be sheared it produces release of the rolling member, a guide for the object for said guide, a mechanical connection between said t'o'ol'holder and said bottom for positively opening said bottom during the shearing operation, means enabling said mechanical connection to effect its return stroke during the return stroke of the tool holder without closing the bottom, a dash-pot, an air escape vent and with a spring put undertension during the shearing for closing the bottom more slowly than said mechanical connection, and means for adjusting said vent during the closing of the bottom.

20. Guillotine shears, comprising a rotating disc, a' guide concentric to said disc, a rolling member freely mounted between the periphery of the disc and the guide, a tool holder penetrating into said guide suificiently close to the periphery of the disc to be reciprocated by the rolling member when the latter is carried round by the to be sheared beyond the tool,- a removable bottom disc between said disc and said tool holder, means for permanently urging'said tool holder towards said disc, means for restoring the rolling member 1 to normal position after it has actuated said tool holder, means for arresting the rolling member in its path in advance of the place of encounter with the tool holder, said means being adapted to release the rolling member, a continuous feeding device for material to be sheared, a stop arranged to be pushed back by said material when the latter extends beyond the tool for a desired length, rolling member release means located between said step and said arresting means said release means being operated by said stop, and a spring between said stop and said last mentioned means sufilciently stiiT not to be compressed by a force equal to the passive resistance of the members put in motion for causing release of the rolling member.

CAMILLO CITO.