US2326697A - Feeding mechanism - Google Patents

Description

.1. STUART, 2D 2,326,697

FEEDING MECHANISM Filed Aug. 20, 1941 5 Sheets-Sheet l Aug. 10, 1943.

J. STUART, 2D

FEEDING MECHANI SM Filed Aug.

L ll

Ulu a 5 Sheets-Sheet 2 www Aug. 10, 1943. 1 STUARTy 2D 2,326,697

FEEDING MECHANISM Filed Aug. 20, 1941 5 Sheets-Sheetl I3 A 'im Il 3543 @MMA 3 gmk@ APatented Aug. 10, 1943 FEEDING MEHANISM Joseph Stuart, II, Wilmington, Del.. asslgnor to Hercules Powder Company, Wilmington, Del., a corporation of Delaware vApplication August 20, 1941, Serial No. 407,563

Claims.

This invention relates to an improved feeding mechanism and is directed especially to a feeding mechanism adapted for feeding a plurality of relatively thin flexible strips of smokeless powder through a machine, such as a punch press or the like, having relatively movable members employing cooperating die members for perform-4 ing cutting or punching operations on the strips. More particularly, the invention relates to a feeding mechanism for pulling a strip comprising a plurality of relatively thin flexible plastic sheets past a blanking and cutting die intermittently so as to present successive portions of predetermined length of the material to the dies.

The feeding mechanism of this invention is especially adapted for moving sheeted smokeless powder past a punching and cutting die in a manner that allows the production of increments suitable for use in various mortars for military use, such as, for example the 60 millimeter, and the 81 mm. types A and B. y

It is well known to feed strip materials to punching and cutting dies by passing the strip between sets of rollers, which rollers bear upon the strip material and force it forward either continuously or intermittently. However, this type feeding device has many disadvantages when it is employed with thin flexible material because there is a tendency to buckle or slip during the various operations. Further, if the rollers are sumciently tight to obtain positive feeding, the material is deformed, and in the case of strip Amaterial comprised of a plurality of relatively thin plastic sheets, there is a tendency to cause the sheetsto adhere to one another. In the case of smokeless powder there is the additional probability of fires or explosions when using the conventional feeding means.

In accordance with the present invention, the above disadvantages are overcome by a novel feeding mechanism which includes a reciprocating hook-like member which may be reciprocated in a line parallel to the movement of the strip material. The reciprocating hook-like portion engages the strip material after the first hole has been punched in the material. Upon engaging the strip material, the hook then reciprocates to move the strip-like material past the cutters,

and during this reciprocating period, pulls the strip material a predetermined distancek along its path of travel. The hook then releases the material and reciprocates in a reverse direction to again engage the strip. Thus, the invention consists of a reciprocating hook which moves in opposition to the line of travel of the material being worked upon, engages the material and moves in the same direction as the material and thereby brings the said material into proper regand moves out of alignment with the dies while they are moving towards engagement. The feeding mechanism reciprocates to each end of its travel at such a rate and under proper timing conditions to present to the dies the proper increment of the strip of material used.

Having now described in general the operation of the machine of this invention, there follows a more detailed description of the apparatus with reference to the attached drawings in which:

Fig. 1 is a side elevation View of a punching and cutting press having the die members thereof separated, and the feeding mechanism at the extremity of its motion opposite to the motion of the strip being acted upon;

Fig. 2 is a side elevation view similar to Fig. 1 partially in cross section showing the die members engaged, and the feeding mechanism at the extremity of its travel when it moves in the direction of travel of the strip material being acted upon;

Fig. 3 is a plan View taken along line 3-3 of Fig. 1; Fig. 4 is a plan view taken along line 4-4 of Fig. l; Fig. 5 is an end view of Fig. l; Fig. 6 is a view taken on line 6-6 of Fig. 1; Fig. 7 is a view taken on line l-l of Fig. l; Fig. 8 is a View taken on line 8-8 of Fig. l; and Fig. 9 is a perspective view of the strip material as it is positioned in the mechanism of Fig. 2.

The following description is of the detailed construction and operation of the feeding mechanism of this invention when it is attached to a punching and cutting press adapted for the production of increment units of smokeless powder comprising a plurality of sheets of powder sewed together by a silk thread along one side thereof and having a hole or holes therein. This will be understood to be a preferred embodiment and should not be construed as limiting the invention, since many changes and modifications may be made therein without distinguishing from the spirit and scope of the invention.

A feeding mechanism of the present invention is attached to a. punching and cutting press conpowder. As illustrated these recesses extend only part way into the supporting block but they may n extend all the way through block I2 and plate II to communicate with some sort of receptacle placed below the machine to receive the vpieces of powder cut by the machine. Fitted in support I2 around the top of recess I4 is a die I6. Above die I6 is a plate I8 having an aperture I3 coinciding with and slightly larger than the die aperture. The plate I8 and die I6 are spaced apart by spacers 26 (Fig. 8) so that the strip material may pass between them and plate I8 is -held in place by bolts 2l. Recess I5 has at one edge a die adapted to cooperate with a cutting edge. The other side of recess I5 is formed by a block 26 particularly adapted to guide the feeding means hereinafter described,

and to serve as a stop for the strip of material. Block 26 is attached to support I 2 by means of bolts 2`I. At one end of support I2 is a feed table or guide 28 for the strip material. which may or may not be attached Ato bed plate I'I or support block I2. u

The upper section or press of the machine is positioned above the .base and is adapted to be intermittently raised and lowered by means not shown to cut and punch the strip material and to simultaneously operate the feeding device. It

comprises a base member 3l to which is attached a, plate 32 by means of bolts 33. On the front end of plate 32 is mounted a punch 34 which is adjustably held in place by means of a set screw 35 and adaptedto cooperate with die member I 6. Also mounted on plate 32 is a cutter 38 adapted to cooperate with die 25 to sever the strip material. At the rear of plate 32 is mounted an arm 39 by means of bolts 40. Rigidly attached to arm 39 is another arm 4I which is perpendicular to arm 39 and extends in the direction of the lower half of the machine. The lower end of arm 4I is tapered off and is provided with a cam surface 42. While a single punch and a single cutter are illustrated, a plurality of such members in any arrangement is contemplated.

The feeding device proper comprises primarily a hook arm and a link 46. Hook arm 45 is adapted to reciprocate by sliding in block 26. For the purpose of keeping it positioned and lubricated members 4'I and 48 are provided on block 26. At the forward end hook arm 45 is tapered to a point so that it will ride up over the forward edge of the strip material and up to the angular edge of plate I8. It will be seen that on its rearward travel the projection 49 will engage and move the strip of material. 'I'he other end of hook arm 4-5 is pivoted to movable link 46 which in turn is pivoted by astationary pvot 50 on pivot block 5I which is rigidly mounted on bed plate II. Secured in the middle of link 46 is a pin 54 on which is a cam. roller 55 (Fig. 5) which rolls on cam surface 42 ofvarm 4I and is constantly urged against said surface by means of a spring 56, one end of which is attached to the end of pin 54 and the other end of which is attached to block I2 by means of an eye bolt 5l. Thus, it will be seen that as the upper member 3I descends roller 55 will ride up cam surface 42 and cause hook arm 45 to iin move carrying withk it the strip of material it has hooked. When the upper member 3i ascends again spring i6 will cause the hook to return and engage a new segment of material Fig. 9 illustrates the type of'material the machine is particularly designed for; a plurality of leaves comprise powder strip 60, which are held together by a thread 6I and the strip is punched or perforated by holes 62. Other perforations and cutting or splitting of the powder lies within the scope of the invention and may be performed by suitable means not illustrated.

The operation consists of feeding the powder strip 66 intermittently to punch 34 and cutter 38 in order to produce an increment or unit of powder which contains a perforation and is ready for use as part of the powder charge of a mortar.

The strip 66 is first fed manually under punch 34 at which time the punch is lowered and a perforation formed, then raised, and the strip moved forwardly by manual means until it' .is positioned so that punch 34 may again perforate the strip in the proper location. Upon raising the die again, spring 56 urges hook arm 45 in a direction opposite to the travel of the powder and the hook arm moves continuously in this direction until it reaches the limit of travel allowable by cam surface 42 which is reached when the press is in the uppermost position. The hook member at this time is in the position shown in Fig. 1, having ridden up over the end of the powder strip lIii! and fallen into a perforation 62 made by punch 34. The press now starts downwardly, and the downward motion causes cam surface 42 and cam wheel 55 to urge` the hook arm 45 in the normal direction of travel of the powder strip Bil, and at the same time to draw the powder strip 60 in its normal direction of travel until it is stopped-by block 26 at which time the cutter and punch are beginning to contact the strip, and these members continue down through the stripeifecting a perforation and cutting an increment from strip 66. When the punching and cutting operation is complete, such as is shown in Fig. 2,"the press begins to rise and the hook arm 45 starts in a direction opposite to the normal travel of thev strip of powder material and again rides up over the end of said strip and falls into the perforation, whereby the process is repeated. This operation allows the strip to be drawn over the dies and gives a smooth efficient feeding action. The pulling of the strip over the dies does not place the strip under pressure and thereby preventsany tendency for the sheets of powder to adhere together or ignite. Any adherence of the sheets is highly undesirable because it affects the ballistics thereof and causes rejection of the powder.

The feeding mechanism in accordance with this invention is positive in action and moves the powder strips through punching and cutting operations in a positive manner which is, however, sufiiciently gentle to prevent excessive stresses being placed upon the powder. There is no buckling possible by the method and there is minimum friction developed in the feeding mech anism. Both of these advantages are very desirable and are actual improvements over the prior art.

Alternatively the portion of block I2 lying between recesses I4 and I5 could be substantially eliminated so that the hook arm 45 extended under punch 34 and engaged the powder strip at that point. Y

As illustrated the device is adapted to operate termined lengths of said strip to said punching 1 on a single strip but a "gang press to handle a multiplicityY of strips and perform a multiplicity of operations is contemplated.

It will be understood that the details and examples hereinbefore set forth are illustrative only and that the invention as broadly described and claimed is in no way limited thereby.

What I claim and desire to protect by Letters Patent is:

1. A feeding mechanism comprising a reciprocating hook-like member 4adapted to impart a step by step movement to a strip of a plurality of layers of smokeless powder by intermittently engaging and releasing said strip by means of perforations in said strip.

2. 'Ihe combination of cooperating members relatively reciprocal toward and away from one another with a feeding mechanism comprising a reciprocating hook-like member adapted tc impart a step by step movement to a strip of a plurality of layers of smokeless powder by intermittently engaging and releasing said strip by means of perforations in said strip.

3. In a machine for the production of increments of perforated smokeless powder, the combination of cooperating punching means and cooperating cutting means with a feeding mechanism comprising a reciprocating hook-like member adapted to impart a step by step movement to a strip of said powder by intermittently engaging and releasing said strip.

4. In a machine for the production of increments of perforated smokeless powder, the combination of cooperating punching means and cooperating cutting means with a feeding mechanism comprising a reciprocating hook-like member adapted to impart a step by step movement to a strip of said powder and presenting predeand cutting means, said hook member being reciprocated by a cam device t operated synchronously with both of said cooperating means, whereby the said hook member is moved in a direction opposite to the direction of travel of said strip when the said cooperating means are in the process of separating and whereby said hooklike member is moved in the direction of travel of the strip when the said cooperating means are moving towards one another to effect engagement, said hook being adapted to ride up over the edge of said strip and catch in a perforation in said strip.

5. In a machine for the production of increments of perforated smokeless powder', the combination of cooperating means for simultaneously cutting and punching, with a feeding mechanism comprising a reciprocating hook-like member adapted to impart a step by step movement to a strip of said powder and presenting predetermined lengths of said strip to said punching and cutting means, said hook member being reciprocated by a cam device operated synchronously with both of said cooperating means, whereby the said hook member is moved in a direction opposite to the direction of travel of the said strip when the said cooperating means are in the'process of

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