US1719366A - Feed mechanism for traversing work sheets - Google Patents

Description

July 2, 1929.

H. A. GRIFFITHS ET AL FEED MECHANISM FOR TRAVERSING WORK SHEETS Filed June 50 1925 4 Sheets-Sheet 1 J y 9- H. A. GRIFFITHS ET AL FEED MECHANISM FOR TRAVERSING WORK SHEETS 4 Sheets-Sheet 2 74.41. iv? H.

Filed June 30, 1,925

J y 1929- H. A. GRIFFITHS ET AL 1.719.366

FEED MECHANISM FOR TRAVERSING WORK SHEETS Filed June 30, 1925 -4 Sheet-Sneet 3 July 2, 1929. H. A. GRIFFITHS ET AL FEED MECHANISM FDR TRAVERSING WORK SHEETS Filed June 30, 1925 4 Sheets-Sheet 4 Patented July 2, 1929.

.UNITED STATES nane PATENT orrrcn,

HARRY ALBERT GRIFFITHS, OF BIRMINGHAM, AND RICHARD HANSON GRIFFITHS, OF SUTTON COLDFIELD, ENGLAND.

1mm) mnennnismronrnavnnsme WORK application filed. June 30, 1925, Serial No. 40,644, and in Great Britain August 14, 19%.

This invention relates to cutting, drawing and; like presses for operating on metal or other sheets or strips, and has for its object to provide improved means for automatically traversing the sheet or strip in a step by step manner across the tools.

.The invention comprises the combination with a slide provided with means for carry iug the sheet or strip, and a guide on which the slide can travel, of a single reeiprocatory member, and a ratchet and pawl or like device acting in such a manner that step by stepmovementscan be imparted from the reciprocatory member to the slide in either direction, the said member being reciprocated from any convenient part of the press, such as the crank shaft, and means for offecting reversal. of motion of the slide by disconnecting the reciprocatory member from its driving member for one half revolution of the crank shaft at each end of the traverse of the slide.

In the four accompanying sheets of enplanatory drawings Figure 1 is a side elevation of a machine constructed in accordance with this invention for cutting out circular or polygonal blanks Figure 4 is an end elevation of the sheet carrier and some of the associated-mechanism shown in Figure 2. a

Figure 5 is an end elevation of the clutch controlling and pawl reciprocating mechanism shown in Figure 2,and Figure 6 is an end ele ation of the pawl oscillating and slide controlling mechanism shown in Figure 2. t

Figure 7 is a side elevation of the driving mechanism for the sheet feeding mechanisn'i. Figure 8 is a frontelevation of the cam and associated lever mechanism shown in Figure 7, Figure 9 is a plan of the clutch shown in Figure 8, and Figure 10 is an end elevation showing the clutch lever and part of the clutch.

In machines for cutting out circular or polygonal blanks from a metal sheet a, the latter is usually traversed step by step past described.

the punch b and. die so that a blank is cut out in eachreciprocation of thepunch. After the completion of one. rowyof punchings, the sheet is moved forward and the next row is cut out during the reverse movement of the sheet, the reversal being repeated at the end of each row, In the application of the invention as shown to machines of this kind, the sheet a is secured atone edge to a holder (Z carried on a slide (2 which is movable on a guide f, the latter being secured to another slide g which movable along a guide it in a direction at right angles to the slide 6. In the arrangement illustrated the sheet .is attached to the holder. by the provision of holes near one edge oftthe sheet which can be engaged with pegs d on the holder.

For imparting the required step by step movement to the slide 1 on the guideh for traversing the sheet across the tools, a bar 2' is secured alongside theslide g and this bar is notched at intervals along its upper edge, the pitch of the notches corresponding to one. half. the pitch of the blanks to be cut from the sheet. (See Figures 2 and 4.) On {the trame of the machlne at a position along side the guide it s mounted a shaft is to which are imparted both reciprocatory and oscillal tory motions. The shaft is carried by bcarin 's as Z, m and on it is secured .ircfcrabl in an adjustable manner) a cam like pawl a which can engage any one of the notches j in the bar-"i. The step by step movement of the slidefl {on the guide lain eitherdircction is effected by the shaft K: through the pawl a. In each cycle the pawl isfirst engaged with the notched bar byan oscillatory movcn'ient of the shaft, and afterwards by a linear motion of the shaft, the pawl acting through the medium of the notched bar, moves the slide (and sheet) from one position to the next. y

Reciprocation of the shaft Z: is eii'ected as follows: A collar 0.011 one end. of the shaft is connected by a link 7) to a lever g on a. shaft r which is oscillated a lover a, link i; and bell crank lever a which is actuated by a cam o (see Figures 7 and 8), the said cam being driven by chains to, a from the crank shaft g of the press. At the completion ofeach row of stampings the action of the above mechanism istemporarily arrested as hereinafter Oscillation Or the share a is Baas a 01- lowsfOn the Shaft 3 is arranged a came 2 I CI rod 6, bell crank lever 7, rod 8 (Figure 7 and thence to a bell crank lever 9 (Figures 2 and 6), link 10 and lever 11 which is mounted on the shaft is between a pair of cheeks on the hearing m, the saidlever 11 being featherkeyed or otherwise suitably connected to the shaft. The action of the above mechanism is to rock the shaft 70 in the direction for disengaging the cam like pawl 71. from the notchedbar Re-engagement of the pawl with the bar is effected by a spring 12 acting onthe lever 11 (see Figure 6).

It will be apparent that the relationship between the actions of the pawl oscillating and reciprocating mechanisms which is suitabl'e' for one direction of motion of the sheet, is unsuitable for the reverse motion of the sheet. Consequently it is necessary to allow the reciprocating mechanism to miss a stroke prior to each reversal of movement of the sheet. This is effected in the following manner. The shaft 13, Which is intermediate to the crank shaft 3/ and the shaft 14 carrying the cam '0, is fitted with a clutch (Figures and The driving element 15 of the clutch which is driven by the chain :20, has provided in one of its faces a pair of pegs 16 adapted to engage a pair of holes in the driven element 17 of the clutch which actuates the chain a. The said element 17 is slidable against a spring 18 by a pivoted fork '19 for withdrawing the part 17 away from the pegs 16. On the fork 19 is mounted an 7 oscillatory stop 20 which normally is out of action. When moved into action it is enaged by a projection 21 on the part 15 and due to the interactionof suitably inclined faces on the parts 20 and 21, the fork 19 is moved in the direction for disconnecting the clutch members. Very shortly afterwards another projection 22 on the part 15 engages the stop 20 and rotates it back into the unobstructive position. As soon as a relative motion equal to one half of a revolution has occurred between the parts 15 and 17, the fork is returned under the action of the spring 18, causing the pegs 16 on 17 to reengage the holes in 15. By thus temporarlly arresting the part 17 which drives the cam Q), the reciprocating and oscillating mechanisms acting on the shaft is are brought into the correct relationship for moving the sheet in the reverse direction.

Rotation of the stop 20 from the unobstructive to the obstructive position is effected by a lever '23 (Figures '7 and 9), rod 24, bell crank lever 25, rod 26 and lever 27, the latter being pivoted (Figures 2 and 5) on a bracket 28 at one. end of the guideh. The lever 27 is provided with a double inclined abutment '29 which co-operates with alike tappet on a bar 30 attached to a rod 31, and the latter has' mounted on it a pair of collars 32 which can be engaged by one side or the other of a striking piece on the slide g. Then the slide approaches one end of its travel the part 33 strikes the adjacent collar 32, and through the rod 31 moves the part 30 past the part 29 on the lever 27 thereby rocking the lever 27 and causing the stop 20 to be rocked through the mechanism above described. The said mechanism and the lever 27 are returned almost immediately afterwards by the action 'of the projection 22 on the stop 20 in readiness for the next operation when the slide 9 approaches the end of its neXt travel.

It has already been mentioned that the pitch of the notches j in the bar 21 is equal to one half the pitch of the stampings. This notch pitch is the one employed for most purposes in which the stampings in one row are staggered in relation to those in the next row. During the movement of the sheet in one direction the pawl engages with alternate notches in succession. During the opposite movement the pawl engages with the intermediate notches. To allow of the reciprocating and oscillating motions of the pawl t0 bebrought into the correct relationship the bar 2' is formed at each end with a broad notch equal in length to the distance between two of the ordinary notches. The pawl slides along its notch without moving the bar I for one half the travel of the pawl, and consequently one half a full motion of the work is lost. This serves to bring the work sheet into proper relation with the tools at the beginning of each reverse motion. As above stated, the mechanism which actuates the bar Z? is disconnected from the crank shaft for a period equal to one stroke of the press.

For controlling the advance of the sheet towards the tools at the end of each motion along the guide h, the guide f has mounted alongside ita rocking bar 34: on which at equal distances apart are secured alternate abutments The slide 0 which carries the sheet a and is movable on the inclined guide 7, is provided with a stop 36 adapted to engage each of the abutments in turn. The disposition of the abutments is such that when the bar is in one position the slide is held by the engagement of the stop with one of the abutments. By rocking the bar about its axis, that abutment is moved away from the stop and the next abutment is brought into the active position. The slide is thereupon released and is moved by gravity or otherwise until it is again arrested. The mechanism employed for automatically rocking the bar is as follows: On the bar is secured a small double armed lever 38 provided with a pair of pegs 39, 40 which are placed in the manner shown in Figure 2. Parallel with the guide it is arranged on the frame of the machine a shaft 41 carrying a pair of levers 12, 13 of unequal lengths, one of which crank leve and link 51 to a lever 52 which is actuated by cam 53 on the shaft 1 When the peg 39 is over the lever a rocking movement of the shaft ell by the cam 53 rocks the bar 3st for the purpose already described. When the peg 40 is over the lever 4.3, a rocking movementot the shai't 41 imparts an opposite movement to the bar 34L. Alternate movements of the bar 34 allows the sheet holder (Z to be moved in a step by step manner towards the tools at the completion of each cross-wise motion of the sheet a.

Feed mechanism as above described is simpler than those ordinarily employed. The one reciprocating element serves to eli'ect the required traversing ot the sheet in both directions. .A single pawl operates in conjunction with the said element in both directions 01' motion of the sheet, and at the end of each motion the relationship between the movements of the said element and the punch is corrected by mo1'nentary disconnection of the mechanism from which the reciprocatory element receives its motion.

It will be apparent that the invention can be carried out in a variety of ways without departing from its essential features, and we desire it to be understood that the invention is not limited to any particular mechanical details as these may be varied to suit dii'lerent conditions or requirements.

Having thus described our invention what we claim as new and desire to secure ,by Let ters Patent is 1. In feed mechanism for traversing a work sheet step by step across the tool of a press, a slide provided with work carrying means, a guide for the slide, a single reciprocatory member, drive means for the reciprocating member, means for lmparting step by step movements from the reciprocatory member to the slide in either direction, the reciprocating movement oi? said member being synchronized with the tool, and means for effecting reversal of motion of the slide by disconnecting the reciprocatory member from the drive means for a period equal to one stroke oi. the press tool.

2. A feed mechanism, as claimed. in claim 1, characterized in that the means for effecting step by step movement of the slide is constituted in part by a notchedbar carried by the slide, said reciprocatory member being mounted for rotary movement, and a pawl mounted on said reciprocatory member and adapted to engage said bar.

3. A feed mechanism, as claimed in claim 1, characterized in that the means for e'tlecting reversal of motion of the slide is constituted in part by a clutch, means controlled in part by the slide and in part by one element of the clutch, whereby the latter is disengaged for one-half a revolution at each end of the motion of the slide.

4. A feed mechanism, as claimed in claim 1, characterized in that the means for effecting reversal of motion of the slide, is constituted in part by means controlled in part by the slide and in part by one element oi. the clutch, whereby the clutch is disengaged tor one-halt a revolution at each end of the motion of the slide, the last mentioned means including a lever acting 011 one part of the clutch, a movable stop on the lever, means actuated by the slide for moving the step into operative position, and means on the other part for acting on the stop whereby in the first place the clutch is put out of action and immediately thereafter the stop is returned to its inactive position.

5. In a feed mechanism as claimed in claim 1, the provision of a driving mechanism for the reciprocating member, said driving; mechanism including a two part clutch and means controlled in part by the slide and in part by one part of the clutch whereby the clutch is disengaged for one-halt revolution at each end of the motion oi: the slide, the last mentioned means including a lever acting on one part of the clutch, a movable stop on the lover, a lever arranged adjacent the slide, a double inclined abutment, a tappet having a like abutment, said stop being connected with the last mentioned lever and said tappet being actuated by the slide.

In testimony whereof we have signed our names to this specification.

HARRY ALBERT lltlhl l llilfi.

RICHARD HANSON GRlFFlTHS.

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