US2821386A - Operating mechanism for folding blade - Google Patents

Description

Jali. 28, 1958 2,821,386

J. R. PETRE OPERATING MECHANISM FOR FOLDING BLADE Filed De. s. 1954 )Nvt/vrom fof/1v R, Per/fc' @rra/wwwa r United States Patent O OPERATING MECHANISM FOR FOLDING BLADE John R. Petre', Cincinnati, Ohio, assignor to The American Laundry Machinery Company, Cincinnati, Ohio, a corporation of Ohio Application December 3, 1954, Serial No. 472,843

2 Claims. (Cl. 270--80) The invention relates to folding mechanisms for the folding of at work articles moving in succession on conveyor means. Since one commercially important exemplication of this type of flatwork articles consists of laundered flatwork pieces, the invention will be described in this connection.

In laundry folding machines, in one of the most conventional methods, a preselected zone of the article is inserted into the bite of a pair of folding rolls, usually by an elongated blade or equivalent means. Folding blades have been mounted in various ways, probably the most familiar being the pivoted type wherein the blade is hinged for arcuate movement, being actuated by a lever under the impulse of power means. The required power impulse is imparted in various ways, for instance by a solenoid, servomotor, or rotating cam, the last-named means having the advantage of being positive, and eicacious.

In use a cam is adapted to be operatively connected, by means of a clutch or otherwise, to a rotating driver, the cam being periodically energized, for example, by a onerevolution clutch mechanism, or a fractional movement clutch mechanism.

Heretofore, when a folding blade was actuated by a rotating cam, it was conventional practice to hold the idle blade and operating lever (these two being often integrally united) by means of a tension spring with the operating cam in contact with the cam follower part of the lever or actuatable portion of the folding blade means. It will be obvious that when the cam is operatively rotated, it must exert sufficient force to overcome inertia and spring bias, and enough additional force to give the lever and blade enough acceleration to execute the folding operation at the precise moment when the preselected part of the article comes to registry with the folding rolls. In certain types of atwork folders, such as the so-called small piece folders, the articles are travelling at relatively high speed, and the folding blade must necessarily come to folding position at high speed. The required high acceleration rate of the blade necessitates a high cam force, to which must be added suicient impetus to overcome the opposed pull of the spring. High accelerations produce forces and stresses within moving members due to inertia, and in many arrangements of this conventional system the retractor spring adds to these stresses, which in lsome instances have caused deformation of the moving members. In such prior art system the one-revolution cam was often quite steep on its rising face to insure the required fast speed of the blade in the forward movement of the working stroke, which created substantial stress, and required a relatively high torque.

An object of the present invention is to overcome the difficulties hereinabove mentioned by an arrangement wherein the blade and lever are spring biased towards folding position, not away from such position as previously, and wherein the cam now acts as a controller or restrainer to normally hold the folding blade retracted against the Patented Jan. 28, 1958 ICC bias of the spring. Other objects and advantages will be apparent as the description proceeds.

In my novel and improved system, the cam has what migh be called a negative contour in the zone which has contact with the blade-operating lever part during forward or folding movement of the bladet This portion of the cam track drops away from the follower during this forward increment of the blade movement, and actually the spring bias is so applied during this increment that the follower tends to assist in the rotation of the cam. Thus the cam during such forward increment exerts no driving force against the blade lever and requires no driving torque.

The return of the blade to idle position can be much more leisurely than its advance to working position, so that the arcuate extent of this return portion of the cam rotation (conventionally in the neighborhood of 270 degrees) may comprise a gradual, uniform rise, to retract the blade and re-tension the spring with a corresponding lower acceleration and lower stress.

My present system, therefore, provides a free-acting blade operator capable of producing a blade movement having any desired speed without undue stress. In this system, if the cam drop is cut back or reversely shaped quite sharply in its rst portion, the follower will barely contact the cam in their complementary movement so that in this case the equation Force=(Mass) (Acceleration) is substantially met. Thus, with the potential energy of the spring force F already stored up, the releasing action of the cam permits this force to be immediately effective on the mass comprising the blade and its operating parts so as to produce the acceleration. In contradistinction, in the prior art system wherein the blade was held in retracted position by spring bias, the force F required to produce actuation of the blade had to meet the equation F (Mass) X Acceleration) -l- (Force of overcoming spring bias).

Proceeding now to the drawings:

Fig. 1 shows schematically the folding end of a small piece folder assembly, arranged in accordance with my invention.

Figs. 2 and 3 are fragmentary vertical sectional views showing, respectively, the blade and operating mechanism in retracted and folding positions.

Fig. 4 shows, diagrammatically, a modied form of the invention.

For a detailed description of the general type of small piece folder here shown, the reader is referred to U. S. Letters Patent No. 2,579,746, granted December 25, 1951, to Clifton S. Malott, lr. Referring to Figs. l and 2, an article to be folded, such as a towel or the like, is conveyed to the right on top of plate 10, being advanced by frictional contact with the lower ight of the endless conveyor 11. As more fully described in the aforesaid Patent No. 2,579,746, lateral portions of the article overhang the lateral edges of plate 1 and are turned up and under, sequentially, by the guide plates 12 and 13 -as the article advances. In the operation of my invention it is immaterial whether the article is thus longitudinally folded, although it is frequently so folded, since the present novel apparatus is shown and will be described in connection with the execution of a transverse fold. The leading edge of the article crosses the gap G shown between guide plate 13 and plate 14 and begins to travel downwardly on plate 14.

In its course of travel the article has passed an initiating switch, trigger, or other means for instituting operation of a measuring timer, with the result that the folding blade 15 is operated when the proper transverse zone of the article .registers with gap G. The structurefor producing this operation will now be described.

When the timer calls for operation of blade 15, a solenoid 16 is momentarily energized which initiates operation of a one-revolution clutch mechanism 17, the 'latterhaving a constantly rotating drive member rotatedy by a chain from the drive system of the machine. A'sprocket on clutch 17 drives a cam shaft 18 by means of a chain 19 and sprocket 20. The shaft 18 has a cam 21 secured thereto. The cam is rotated counterclockwise from the position of Fig. 2 to that of Fig. 3.

The blade 15 is attachedl on the end of a swingable arm 22 which is pivoted at an intermediate point'23, the other end of the arm 22 being attached to a tension spring 24 which is fixed at 25 on the frame. From the structure so far shown, it is obvious that the blade is spring biased to folding position, but it is normally restrained by the linkage now to be described.

A pivoted rocker arm 26 has a follower roller 27 in contact with cam 21. Theend of the rocker arm is connected to the blade arm 22 by a link 28, the said link being pivoted at both ends respectively to the rocker arm and the blade arm. Consequently, as cam 21 rotates counterclockwise, roller 27 ridesdown the rapid drop 21a'ofthe cam permitting link 28 to move to the right, as shown in Fig. 3 ,l under the bias of spring 24. This drop, from the crest to the trough of the'cam track, can take place over any angular extent desired, althoughin the present instance it is about 90 from the starting pointlofFig. 2 to the finish as shown in Fig., 3. This short arcuate portion of cam rotation is actually desirable inrestraining the operation just the amount required for swift, but not violent action. Were the situationreversed, and were the prior art structure being used, a rise-from trough to crest over an arc of 90 would require an inordinate torque and would be inclined to set up quite undesired stresses in moving the blade with the same speed.

In this particular embodiment it was desired'to have the folding blade move back quickly out of the way of the article, and consequently the cam-rise 2lb was shaped to give a fast but uniforminitial retraction followed by a slow completion of the remaining retraction. The transversely folded article, emergingfrom rolls '30' andv 31 is carried along curved plate 32S in-anysuitable way, being eventually delivered 4to a stacker 33.

The form of the cam, as well as the blade mounting, spring connection, etc., can'he-varied in accordance with the particular folding apparatus yaslongjas't'hesignificant feature is retained, namelythespringbiasing the'blade to wardsoperating position, `with cammed return of the blade to idle position. One somewhat modified arrangementis indicated in the device shown at Fig. 4 in'which the carn35 operates directlyfagainstlthe end of a bell crank lever'3'6- which-carries the blade 37. The spring 38, ofcourse, biases the blade towards folding position. Herealso, with" the cam 3S rotating clockwise, the drop alongthe cam track Yporti'on'35a is quite'sudden, tol permit exceptionally rapid' blade operation, after whichl thercamV riseY 35'b is somewhat more gradual. The'cornbination of lthespring, bladegassembly, and cam' could advantageously be so arranged-that the'forces are utilized most beneficially.' For instance, as suggested? in Fig'. 4,-the'pointsof spring'attachL ment 39 and 40=and thepivot point' 411 for the'blade crank arm lie practically in a straight line when the blade is arriving at folding position, so that movement of pivot point 40 past this straight line begins to be restrained by the spring thereby reducing the inertia force required to stop and reverse the blade motion, and consequently reducing the torque applied to the cam in withdrawing the blade. One of 'the advantages-.of my invention resides in this, that the cam contour. can be utilized. to control acceleration and deceleration While the spring provides a stored impetus, always applicable when needed.

From the above description, it will be apparent that the essentialsA of the inventionreside in amovable folding member, a spring biasing the member towards operating position, and a cam operatively effective on the member to restrain it in opposition to the spring bias, the cam being adapted to be rotated to permit the spring bias to take effect. Wheneveracam follower is mentioned herein or in the appended claims, it ywill beunderstood that any part of the folding blade assembly which is in contact with the cam track may serveas a cam follower, and itwill be further understood,that.thefolding blade assembly includes not only the blade itself, but any mounting means, rocker arms, linkages, orother mechanical devices suitable. topermit or facilitate movement of the folding blade, it being of course feasible to substitute a sliding, reciprocatory blade instead ofthe pivoted, arcuate swinging blade herein shown and described.

What I claim is:

1. In a folding device wherein an article. is moved-along a path towards afoldi'ng zone, means forfolding said article comprisingaframe, a folding arm, means-onv said frame providingY a pivot vp oint for said arm, a swingable end'of saidarm having-a foldingblade thereon, a tension spring having one endattachedto said frameand the other end to said'armandso disposed that, whenotherwiseunrestrained, the two ends ofsaidspringand the pivot point o'f said arm assume a co-linear position on a center line, said arm being swingable away from saidY center line, against spring bias, either forwardly towards said folding zone or rearwardly away fromsaid folding zone, and a cam having a track-portionabuttable againstsaid arm and effective thereon to normally maintain said arm and blade over center away from said -folding zone, said track havingV a cam-drop portion permittingsaid arm and blade toreturn over center towards an operating position in said folding zone.

2. A folding device of thecharacter described in claim 1 wherein said cam .track has a cam-rise portion following said cam-drop portion, ysaid cam-drop portion being relatively precipitate to permit rapid arm Aswing-to folding position, and the cam-rise portion being more gradual, to cause positive but .more restrained arm movement away from folding position.

References Cited in the le of this patent UNITED STATES' PATENTS 1,465,440 Houston Aug. 21, 1923 1,961,633 Ehlig June 5, 1934 2,335,970 Schmidt Dec. 7, 1943 2,355,105 Preston Aug; 8, 1944

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