Chain Thread Severer With Light Source And Photocell Having Relative Reciprocal Movement

Abstract

A device for cutting chain thread, such as results from a prior sewing operation, which interconnects the trailing and leading edges of handkerchiefs or the like. The cutting mechanism initially moves in the feed direction with the handkerchiefs, which movement effectively both enlarges the opening between adjacent handkerchiefs and pulls the chain thread taut and then subsequently moves in a counterfeed direction across the opening, during which time it effectively severs the taut chain thread.

Description

The present invention relates generally to sewing thread cutting devices, and more particularly to an improved chain thread severing device.

In mass production sewing operations, such as for example the hemming of handkerchiefs or like cloth blanks, the blanks are fed through the sewing station resulting not only in the deposit of the thread in the cloth but also in continuations of this thread extending in an interconnecting relation between adjacent blanks. Economic mass production does not permit terminating the sewing operation of the sewing machines to eliminate this so-called chain thread, and thus it must subsequently be severed preparatory to further processing of the individual handkerchiefs. In some instances, in fact, the chain thread is required not only to be severed but, for appearance's sake, it must be trimmed close to the handkerchief edges. There is thus a need for effectively achieving chain thread severing and trimming. While there are numerous thread cutters available, there is none which operates in such a controlled manner as to enable thread trimming close to the product edges and, thus, such trimming is usually done manually.

Broadly, it is an object of the present invention to provide an improved chain thread severing device overcoming the foregoing and other shortcomings of the prior art. Specifically, it is an object to provide a chain thread severing device, in the operation of which, the chain thread is so conditioned that severing is achieved at one or more precise locations. The severing device is accordingly also readily usable for trimming.

A device for severing sewing thread demonstrating objects and advantages of the present invention includes a cutting mechanism arranged for reciprocating movement parallel to the feed direction of movement of the interconnected handkerchiefs or the like. Thus, initially the cutting mechanism moves with the handkerchiefs to a starting position for a subsequent cutting stroke, while the same movement of the handkerchiefs is effective in pulling the chain thread taut between the handkerchiefs. The taut thread, which by virtue of its taut condition is in a predictable location and of a predictable length, is then severed or trimmed, as desired, as the cutting mechanism moves in a counterfeed direction through its cutting stroke.

The above brief description, as well as further objects, features and advantages of the present invention, will be more fully appreciated by reference to the following detailed description of a presently preferred, but nonetheless illustrative embodiment in accordance with the present invention, when taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a perspective view of a chain thread severing device according to the present invention;

FIGS. 2a--2e are plan views illustrating a typical cycle of operation of the device. Specifically, FIGS. 2a--2c illustrate the movement of the trailing and leading edges of chain thread connected cloth blanks through feed movement preparatory to the severing of the chain thread, and FIGS. 2d and 2e illustrate movement of the severing device per se in a counterfeed direction during which cutting or severing of the chain thread is achieved.

Reference is now made to the drawings wherein there is shown a thread severing device, generally designated 10, demonstrating objects and advantages of the present invention. The device 10 is specifically useful in severing sewing or so-called chain thread 12 which results from typical sewing operations employed to finish cloth blanks 14, which may be handkerchiefs, scarves or other like items. Specifically, at a sewing station (not illustrated) the sewing thread may be deposited along the edges of the blanks 14 to produce hems 16 and thus finished edges on opposite sides of the blanks 14. Consistent with economic mass production, the sewing operation is not terminated as each successive blank 14 is carried in a feed direction 18 past the sewing needles, but rather said sewing operation continues and thereby produces chain thread lengths 12 which interconnect the trailing edge 20 with the leading edge 22 of adjacent blanks 14. It is the essential function of the device 10 to cause severing or cutting of this chain thread 12.

Device 10 includes a conveyor 24, preferably in the form of an endless belt 26 appropriately entrained about supporting rollers 28 located at its opposite ends. As clearly illustrated in FIG. 1, the upper run of the belt 26 is effective in carrying a succession of interconnected blanks 14 in the previously noted feed direction 18, which direction it will be understood carries the blanks 14 towards two identically constructed cutting mechanisms 30 and 32. For brevity's sake, only the construction and operation of cutting mechanism 32 will be described.

Cutting mechanism 32 is mounted for reciprocating movement in the feed direction 18 and also in the opposite counterfeed direction 36, by virtue of including a bracket 38 appropriately mounted for sliding movement on guide rods 40 and 42 oriented parallel to the longitudinal dimension of the conveyor 24. A crank mechanism 44 is connected to the bracket 38, in the manner clearly illustrated in FIG. 1, so as to impart reciprocating movement 34 to the cutting mechanism 32.

Bracket 38 terminates in an L-shaped arrangement of arms 46 and 48, the latter arm 48 extending in a clearance position over the marginal edges of the blanks 14. Specifically, arm 48 includes a vertically oriented cutting implement or cutter 50 which is located directly above the path of movement of the chain thread 12. That is, cutter 50 has a cutting edge oriented transversely of the location occupied by the chain thread 12 as each successive length thereof is carried by the conveyor 24 past the cutting station defined by each of the cutting mechanisms 30, 32. Each cutter 50 is preferably actuated through a vertical cutting stroke by a pressure air cylinder 52, the return stroke of the cutter being achieved through the urgency of a return spring (not shown) upon the venting of the pressure air to atmosphere.

Mounted at the extreme free end of the arm 48 is a photocell control circuit 54 including a downwardly directed light source 56 and a cooperating photocell 58. Operating in a manner which is well understood, whenever the light beam 60 is permitted to impinge upon the photocell 58, this results in the closing of the circuit 54 with the further result that the cutter 50 is actuated by the cylinder 52 through a downward cutting stroke against a cutting plate 62 which extends horizontally from the base of the arm 46 in a protective position over the marginal edges of the upper run of the conveyor belt 26. Naturally, any interposed chain thread 12 which is contacted by the cutter 50 as it comes down against the cutting plate 62 is effectively cut or severed.

From the foregoing, it should be readily appreciated that successful and proper functioning of the cutting mechanism 32 (and thus also of cutting mechanism 30) requires control over the intervals of time when there is light beam impingement upon the photocell 58. Stated another way, it is desirable for proper functioning that the photocell 58 be covered, in this instance by the blanks 14 during the interval of operation when it is desired not to operate the cutter 50, and that photocell 58 be uncovered during the other interval of operation when it is desired to have a cutting stroke of the cutter 50. The manner in which this is achieved is illustrated in FIGS. 2a--2e which illustrate progressive positions of movement of the cloth blanks 14 with respect to the photocell 58 embodied in the free end of the cutting plate 62.

FIG. 2a illustrates the assumed starting position of the cycle of operation of the cutting mechanism 32. In this starting position, chain thread 12 adjacent the photocell 58 is severed and the cutter 50 and light beam 60 will be understood to have been cranked to their rearward positions, as illustrated, in which light beam 60 is behind the photocell 58.

From the starting position depicted in FIG. 2a, simultaneous operation of the conveyor 24 and of the crank mechanism 44 results in movement of both the blank 14 and of the light beam 60 in the feed direction 18, the latter moving toward its forward crank position. This intermediate position is depicted in FIG. 2b wherein it will be noted that movement of the light beam along the path which crosses over the photocell 58 nevertheless does not operate the photocell circuit 54 because at the time of passage of the light beam over the photocell 58 the blank 14 is in a covering position over the photocell 58.

Ultimately, the cutter 50 and the light beam 60 are urged to their forward crank positions as depicted in FIG. 2c. In this position, the light beam 60 is now in front of the photocell 58. Moreover, feed movement 18 of the conveyor 24 is conducted to an extent which carries the trailing edge 20 of a blank 14 beyond the photocell 58 and is terminated just prior to the leading edge 22 of the next succeeding blank 14 reaching the photocell 58. Thus, the photocell 58 is within an opening created between the blank trailing and leading edges 20 and 22, respectively. It should further be noted that in the creation of the opening 64 that the chain thread 12 connecting the edges is placed in an advantageous taut condition. This taut condition, in turn, is effective in providing as wide an opening 64 as is possible to provide between the blanks 14 and also in aligning the chain thread 12 beneath the transversely oriented cutting edge of the cutter 50.

Chain thread 12 between the successive blanks 14 is now in an advantageous position for severing or cutting. This cutting, moreover, automatically occurs upon the cranking of the cutting mechanism 32 in a counterfeed direction 36 while operation of the conveyor 24 is temporarily halted, all as is clearly illustrated in FIGS. 2d and 2e. Specifically, during counterfeed movement 36 of the cutting mechanism 32, light beam 60 is moved across the uncovered photocell 58 and results, in the manner already noted, in a cutting stroke of the cutter 50. This cutting stroke occurs swiftly and at a time when the cutter 50 is over the chain thread 12. As illustrated in FIG. 2e, ultimately the cutter 50 and light beam 60 are cranked to a rearward position in which the light beam 60 is moved beyond the photocell 58 which permits return spring lifting of the cutter 50. It should be recognized that the FIG. 2e positions of the cutter 50 and light beam 60, as well as the condition of the disconnected successive pair of blanks 14 are similar to that depicted in FIG. 2a, which was the assumed starting condition of the cutting operation of the cutting mechanism 32.

From the foregoing description it should be readily appreciated that each of the cutting mechanisms 30 and 32 effectively sever chain thread 12 interconnecting successive blanks 14 while the chain thread 12 is in an advantageous taut condition and, further, while a maximum opening 64 exists between the blank trailing and leading edges 20 and 22, respectively. As a consequence, it is possible, if it is desired to do so, to not only sever the chain thread 12 but also to achieve a trimming function. That is, if the circumstances warrant it, the chain thread 12 can be cut at two locations rather than in the single medial location as illustrated herein. These two locations, moreover, can be respectively adjacent the edges 20 and 22 so that in the process of severing the chain thread 12 there are no length portions thereof which require trimming from the blanks 14.

A latitude of modification, change and substitution is intended in the foregoing disclosure and in some instances some features of the invention will be employed without a corresponding use of other features.

Claims

What I claim is:

1. A device for severing thread interconnecting cloth blanks comprising a conveyor operatively arranged to transport plural cloth blanks in a prescribed feed direction, at least two adjacent ones of said cloth blanks having a connecting thread joining the respective trailing and leading edges thereof, a thread severing mechanism including a reciprocating cutting implement and control means for said mechanism operatively effective to simultaneously actuate both said conveyor and said thread severing mechanism through said feed direction to provide an opening between said respective trailing and leading cloth blank edges of an optimum extent and subsequently to actuate said thread severing mechanism in a reverse direction through said counterfeed direction across said opening to thereby cause the severing of said connecting thread by said cutting implement thereof.

2. A thread severing device as defined in claim 1 wherein said thread severing mechanism includes a photocell circuit operatively effective to selectively cause a cutting stroke of said cutting implement.

3. A thread severing device as defined in claim 2 including a crank mechanism operatively connected to actuate said thread severing mechanism in said feed direction and subsequently in a reverse counterfeed direction during which said photocell circuit is operatively effective to sense the presence of said opening between said blanks beneath said cutting implement.

4. A thread severing device as defined in claim 3 wherein said photocell circuit includes a light source carried by said thread severing mechanism and a light-actuated switch located along the path traversed by said thread severing mechanism during said counterfeed movement thereof.