Stacker Mechanism

The present invention relates to a stacker mechanism, especially though not limitatively, used in combination with sewing machines for removing a work piece or the like element from the work area.

The operation of a stacker mechanism in general requires that the wiper mechanism employed therewith is first moved from a non-contacting position relative the work piece to a contacting position. Once the fabric has been engaged, it is then necessary to impart to the wiper mechanism a motion enabling removal of the work piece from the work area. Finally, it is necessry to return the wiper mechanism to its initial position where it is ready to be utilized on the following work piece.

In known arrangements of this type, such has been used in connection with industrial sewing machines or the like, the fabric work pieces are fed through the sewing machine and are then engaged by a stacker mechanism at the rearward side of the machine. On heretofore known stacker devices there is provided at the free end of the pivot arm, a pneumatic cylinder means which is operable to vertically move the wiper mechanism into and out of engagement with the fabric work piece. The horizontal reciprocal or turning movement required for removing the fabric work piece from the work area is imparted to the wiper mechanism by a second pneumatic cylinder means. The end result being that the wiper mechanism is moved in a rectangular motion. However, these stackers are of expensive construction and have heretofore required a relatively complicated control device enabling sequential operation of the series of pneumatic cylinder means in order to obtain the necessary movement required to be imparted to the wiper mechanism.

In view of the foregoing, and in accordance with the present invention, there is provided a stacker mechanism which imparts to the wiper mechanism thereof a rectangular motion while at the same time utilizing a single drive mechanism and a simple control system for removing the work pieces from the work area of the machine. The present invention includes a frame, an arm, and a support member having first and second pivotal connections. The first pivotal connection rotatably secures the support member to the frame and allows the arm to be vertically rotated with respect to the frame. The second pivotal connection rotatably secures one end of the arm to the support and allows movement of the arm in a horizontal direction. A horizontal motion retarding assembly which includes a pair of friction discs, a resilient compression means, and a laterally adjustable nut, is operatively associated with the arm at the second pivotal connection. The friction discs are disposed in facial abutment with the top and bottom sides of the arm and the resilient compression means is situated between the nut and the friction disc. The motion retarding assembly applies to the second pivotal connection a higher coefficient of friction than is inherent with the first pivotal connection. This higher coefficient of friction provides a restraining force to the horizontal turning movement of the arm. A driver is employed for forcibly moving the arm about the pivotal connections. The driver is pivotally connected to the frame at a point, relative the machine, which is above and in front of the drivers pivotal connection with the arm. The difference between the coefficient of friction applied to the second pivotal connection and the coefficient of friction inherent with the first pivotal connection results in a rectangular motion being imparted to the wiper mechanism upon cyclic movement of the arm by the force driver means. With an embodiment of this sort there is provided a stacker apparatus which uses a single drive for imparting to the wiper mechanism the necessary motion and does not require the complexity of the control system for sequentially operating a series of pneumatic cylinders.

There is further provided by the present invention, a rotatable work support which is immediately rearward the work support for the machine. The top surface of the rotatable work support is in parallel alignment with the work support of the machine and is adapted to be rotatably moved between a first position, where it is in position to support the work piece carried by the wiper mechanism and a second position, out of the path of movement of the wiper mechanism. Once the support has been removed from beneath the work piece, the latter is free to fall onto a table which is in general vertical alignment with the first position of the rotatable work support whereby the work pieces are stacked in a position removed from a working area of the machine.

In view of the above, it is an important object of the present invention to provide an improved stacker mechanism for removing flexible sheet like workpieces from the work area.

Another object of this invention is the provision of a stacker mechanism of the general type referred to which is of simple construction and does not require a complexity of control systems for operating same.

Other objects, features and advantages of the present invention will become apparent upon reading the following specification when taken in conjunction with the accompanying drawings.

FIG. 1 is an elevation view of a stacker mechanism constructed in accordance with the principles of the invention, the illustrated position of same corresponding to the operative position of the device;

FIG. 2 is a top plan view of FIG. 1;

FIG. 3 is an enlarged fragmentary elevational view of one end of the stacker mechanism shown in FIG. 1;

FIG. 4 is a sectional view taken along line 4--4 of FIG. 3.

Referring now in more detail to the drawings, in which like reference numerals indicate like parts throughout the several views, and for the purpose of illustration, but without limitation, the invention will be described herein as being secured to a work support means 1 which serves to support fabric work pieces or the like which are being worked on by a sewing machine 2. However, it should be appreciated that the present invention is equally applicable to other types of machines and should not be limited to use with sewing machines. A rotatable support means 3, having a top surface means 3' which is in general parallel alignment with the top surface means of the work support means 1 is situated so that it may intermittently support the fabric work pieces 5 when the stacker mechanism is swung to its second position as shown in phantom lines in FIG. 2. The rotatable support means 3 is pivoted about an articulate connection means 7. A drive means 6 is suitably connected to the articulate connection means 7 for rotating the support means 3 from the position shown in FIG. 2 to a position where the top surface means 3' is no longer in position to support the work piece 5. Located below and in vertical alignment with the rotatable support means 3 is a table means 4 which is the final receiving point for the sewn workpieces once they are released from the stacker mechanism as will be hereinafter discussed.

As may be best seen in FIGS. 3 and 4, secured to the work support means 1 by any suitable means, is a frame means 8. The frame means 8 has secured rewardly thereof a first pivotal connection means 42. The first pivotal connection means 42 is comprised of a support means 13 which journals a horizontal pin means 11 which is secured by any suitable means, such as 12, within bore means 9 located in the rearwardly extending portion means 40 of frame means 8. The first pivotal connection means 42 allows rotational movement of the support means 13 about the longitudinal axis of the pin means 11. The degree of rotation of the support means 13 in a counterclockwise direction, as viewed in FIG. 3, is limited by an adjustable limit means 20 for reasons discussed hereinafter.

Upwardly extending from the support means 13 is a second pivotal connection means 44 which is comprised of a vertical stud means 14 and the first end means 15 of a pivotal arm means 16 which journals the stud means 14. Operably associated with the first end means 15 of the arm means 16 is a horizontal motion retarding assembly means. The horizontal motion retarding assembly includes, a pair of friction disc means 17, a resilient compression means 18, and a nut means 19. The friction disc means 17 are mounted about the stud means 14 and are in facial abutment with the first end means 15 of arm means 16 which is disposed therebetween. The nut means 19 is laterally adjustable along the free end 46 of stud means 14. Disposed between the nut means 19 and the friction disc means 17 is the resilient compression means 18 which, as shown in the preferred embodiment, is in the form of a series of Bellevidier washer means. The resilient compression means 18 is arranged to press against the friction disc washer means 17 whereby creating a higher coefficient of friction at the second pivotal connection means 44 relative the first pivotal connection means 42.

The stacker mechanism of the present mechanism is further provided with an actuation means or a force drive means 22 which may be in the form of a pneumatic cylinder means. The force drive means 22 is fixedly secured as at 21 to the frame means 8 by any suitable method, the one shown in the preferred embodiment being a ball and socket joint means. As shown in FIGS. 1 and 2 the other end 23 of the forcible drive means 22 is connected to the pivotal arm means 16 in a similar manner. It should be pointed out, that the force drive means pivotal connection 21 is connected to the frame 8 at a point which, relative the machine means 2, is above and in front of the pivotal connection 23 on the force drive means 22.

A conventional wiper mechanism means 28 is rotatably secured at the second end means 48 of the pivotal arm means 16 by pin means 27. Extending parallel to the arm means 16 is a link means 25 which is pivotally connected to the support means 11 as at 24 and is pivotally connected to the wiper mechanism means as is generally shown at 29. The distance between the pivotal connections 24 and 29 is equal to the distance between the stud means 14 and the pivotal connection 27 whereby forming a parallel bar linkage means. This parallel linkage means arrangement allows movement of the wiper mechanism means 28 in a parallel path whereby no disorientation of the work piece as it leaves the work area occurs.

As may be best seen in FIG. 1, a control means 31 is located on the undersurface of the work support means 1 and is connected to a source of fluid under pressure (not illustrated). Conduit means 32 lead from the control means 1 and are connected to the first and second means 50 and 52 of the force drive means 22. A further conduit means 33 connects the control means 31 with the drive means 6 for supplying the necessary force for pivotally moving the rotatable support means 3 about the articulate connection 7. The operation of the control box means 31 is controlled by a photosensor means which includes a light source means 34 and a cooperative photo cell means 35 both of which are in close proximity of the working area of the machine for sensing the presence, or lack thereof, of a material work piece 5.

Upon exposure to a light beam from the light source means 34, which happens when the work piece has been passed through the work area of the machine, the photo cell means 35 is rendered effective to produce a signal which is transmitted to the control means 31. The signal to the control means 31 serves to deliver fluid under pressure to the first end means 50 of the force drive means 22. It should be appreciated that the position of the stacker mechanism during sewing is shown in phantom lines in FIG. 1 and solid lines in FIG. 2. The deliverance of fluid under pressure to the first end means 50 of the force drive means 22 enables activation of the latter whereby forcibly moving the arm means 16 in a downward pivotal motion about the first pivotal connection means 42. Keeping in mind that there is resistance to horizontal turning movement of the arm means 16 supplied by the horizontal motion retarding assembly it is apparent that initial movement of the arm means 16 is constrained to move in a vertical plane since the coefficient of friction at the first pivotal connection means 42 is less than the coefficient of friction at the second pivotal connection means 44. The downward pivotal motion of the arm means 16 toward the work surface continues until such time as the wiper mechanism means 28 has made contact with the work piece means 5 and the work support means as shown in solid lines in FIG. 1. The work support means 3 prevents further downward pivotal motion of the arm means 16. Once the arm means 16 has been arrested from further vertical movement, the continual actuation of the force drive means 22 delivers to the arm means 16 a force having a horizontal component which is greater in magnitude than the resistance to turning movement force placed upon the arm means 16 by the motion retarding assembly means whereby rotation of the arm means 16, about the second pivotal connection means 42, in a horizontal plane occurs. The horizontal movement of the arm means 16 and the wiper mechanism means 28 carried thereby removes the work piece 5 from the working area and moves the work piece and the arm means into the phantom line position shown in FIG. 2. It should be appreciated that the work piece shown in phantom lines in FIG. 2 is now supported by the rotatable support means 3.

With reference to the rotatable support means 3, it should be noted that the control means 31 is adjusted so as to maintain the rotatable support means 3 in the position shown in FIG. 2 for a predetermined length of time after receiving the initial signal from the photo sensor means 35. Upon expiration of this predetermined extent of time, the control means supplies fluid under pressure, or as may be equally applicable, an electrical signal, to the drive means 6 which in turn forcibly rotates the table means 3 about its articulate connection means 7. The engagement between the wiper mechanism means 28 and the work piece means 5 prevents the latter from being carried along with the rotatable support means during movement of same. Once the rotatable support means 3 and more particularly the top surface means 3' has been removed from supporting the work piece means 5 the latter is free to fall onto the table means 4 where it is stacked in an area removed from the work area. Once the fabric work piece has been stacked on the table means 4, the control means 31 simultaneously returns the rotatable support means 3 and the pivotal arm means 16 to their initial positions. That is, the fluid under pressure is removed from the first end means 50 of the actuator 22 and transferred to the second end means 52 thereof whereby forcibly retracting the actuator to its initial position. Upon retraction of the force drive means 22 the pivotal arm means is again initially swung in a vertical direction away from the work support 1 about the first pivotal connection 42 due to the higher coefficient of friction inherent at the second pivotal connection 44 relative the coefficient of friction at the first pivotal connection 42. The vertical rotation of the arm means continues until such time as the limit means 20 arrests the pivotal motion of the support member 20 and the arm means 16 carried thereby in the counterclockwise direction as viewed in FIG. 3. The continued retracting force delivered to the pivotal arm means by the force drive means 22 can no longer exert a vertical force on the arm means in view of the limitations imposed thereon by the limit means 20. Therefore, the horizontal force component of the retracting force overcomes the magnitude of resistance to turning movement of the arm exerted on the second pivotal connection by the horizontal motion retarding assembly means whereby turning the pivotal arm means in a horizontal plane and returning same to its initial position as shown in phantom lines in FIG. 1.

By comparing the preferred embodiment shown in the present invention with that which is shown in the prior art, it is evident that there has been shown a simplified form of a stacker wherein utilizing a single force drive means 22 rather than a plurality thereof such has been shown in the prior art while at the same time imparting to the wiper mechanism the required motions for removing a fabric work piece or the like from the working area of a machine. Along with that, it should be appreciated that a simple control mechanism is provided whereby enabling actuation of a single force drive member and wherein mechanical workings have been utilized to impart a rectangular motion to the wiper mechanism rather than having to operate a complex control mechanism for sequentially actuating a series of pneumatic drives. In view of the above, it is felt that there is provided a stacker mechanism which removes from the work area of the machine a work piece and deposits the same in an area removed therefrom whereby quick access may be made thereto in a safe and efficient manner.

Thus it is apparent that there has been provided, in accordance with the invention, a stacker mechanism that fully satisfies the objects, aims, and advantages set forth above. While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications, and variations as fall within the spirit and broad scope of the appended claims.