US3134939A - Jam clearing device - Google Patents

Description

May 26, 1964 T. B. EDDY 3,134,939

JAM CLEARING DEVICE Filed Nov. 20, 1959 5 Sheets-Sheet 2 JNVENToR. THEODOIQE B. EDDY A TTOPNE Y May 26, 1964 T. B. EDDY 3,134,939

JAM CLEARING DEVICE Filed Nov. 2o, 1959 3 Sheets-Sheet 3 `l=i=1.50&. 7

Ms Ms CS C5 JNVENToR. THEODORE B. EDDY BY #www AT TON E Y United States Patent O 3,134,939 IAM CLEARING BEVICE Theodore B. Eddy, Brookfield, Conn., assigner to Heli- Coil Corporatien, Danbury, Conn., a corporation of Delaware iiled Nov. 20, 1959, Ser. No. 854,330 6 Claims. (Cl. S18-475) The invention relates to a jam clearing device. In certain conventional machines, workpieces are picked up by a movable element from a stock to be conveyed to a place where the pieces are to be'worked. It is frequently essential that the workpieces are aligned in a predetermined position when they arrive at the place of working or at a point from where they are further conveyed by means other than the mentioned element. In order to ensure proper positioning, means are conventionally provided which traverse the path of the element for the purpose of properly aligning a piece on the element if it is not in proper position from the start. However in such cases it happens that owing to a non-properly located piece a jamming occurs whereby the movements of both the element and the directing means are stopped. There are also other types of machines susceptible of jamming in a similar manner.

It is an object of the present invention to provide means whereby, at least in many events, such a jam can be automatically cleared.

The invention further aims to provide means whereby the operation of the jam clearing device is repeated if the jam is not cleared on a iirst operation of the device.

The invention also aims to provide a signal, be it acoustic or visual, when the jam clearing device operates, so that if, upon repeated operation of the device, the jam is not cleared automatically, the jam can be manually cleared by an operator.

Still another object of the invention is the provision of a jam clearing device, applicable to a movable workpiece pick up element and a workpiece aligning member traversing the path of the mentioned element, whereby the directions of movement of the element and the member are slightly reversed when a jam occurs whereafter normal operation is resumed.

One type of a machine with a movable element and workpiece aligning means of the kind to which the present invention is applicable is disclosed in U.S. Patent 2,889,960 to Brancato et al. of .Tune 9, 1959. For this reason the present invention will be further described as applied to such a machine. However, it is to be understood that thereby no limitation of the invention is intended which will be applicable to certain other conventional machines with the same or similar effect.

Further objects and details of the invention will be apparent from the description given hereinafter and the accompanying drawing illustrating an embodiment thereof by way of example.

In the drawing:

FIG. 1 is a longitudinal cross-section of an embodiment of the invention applied to a hopper feeding mechanism for cylindrical wire coils.

FIGS. 2 and 3 are front view and side elevation, re- 'Y spectively of the end of a coil pick up arm and an aligning blade of the mechanism of FIG. l;

FIG. 4 is a longitudinal cross-section of a part of the device according to the invention and shown in FIG. l,

ice

` FIG. 7 shows the same circuit during operation of the jam clearing device.

Referring now to the drawing FIG. l, in a machine frame 1i), a first shaft 1I is journaled at 12 and 13, and carries at its free end a hub 14 with a plurality of radial pick-up arms 15 which upon rotation of the shaft, can pick up on their tangentially bent ends 16 from a lower hopper (not shown) tubular articles as shown in FIGS. 2 and 3 in the form of cylindrical wire coils. Another shaft 17 is also journaled in the frame 10 at 18 and 19 and carries a iiipper blade 20 with an approximately oval hole 21 ending in a slot Z2. The hole and slot register with the plane of the rotation of the arms 15. The shafts are connected for common rotation by a gear 23 on shaft 11 and a pinion toothing 24 on shaft 17 so that the latter rotatesfaster than shaft 11. The ratio of 'transmission and setting of the blade 20 on shaft 17 is such that upon rotation in the direction of the arrows a and b in FIG. 2 the blade will pass each pick-up arm end 16 with a peripheral speed higher than that of the arm ends. If during such movement a wire coil is properly located it will freely pass through the oval hole of the blade. If however a coil is improperly seated on an arm end and can not be aligned by the passing blade it will be stripped from the arm end the same as a second coil which may cling to a properly positioned one.

Now it may happen, that a coil is so positioned on an arm end that upon the engagement by the blade a jam occurs which causes a stoppage of the operation of the machine. In order to clear such jam, means are provided to reverse slightly the rotation of the pick-up arm assembly for a small fraction of a turn and a commensurate reverse rotation of the flipper blade when a jam occurs, thereby usually allowing a jamming coil to fall clear. For this purpose a special pulley 25 is connected with a pulley 26 on shaft I7 by means of a V-belt 27. Of course other forms of driving and driven wheels, such as a meshing pinion and gear may be used instead of the pulleys. However the pulley and belt connection is preferred on account of its slightly yielding property when sudden shocks occur. Pulley 25 has coaxially therewith an outer tubular extension 2S and a shorter inner tubular extension 29 so that between both extensions an annular space 30 is formed which is wider at 31 between the ends of the extensions than close to -the bottom of that space near the pulley. Substantially throughout the length of the inner extension the latter is provided with an interior screw thread 32, whereas the bore 33 of the V-grooved portion 34 is cylindrical and of a diameter at least as large as the major diameter of the thread 32. An adapter,

in general denoted by 3S comprises a disc 36 from which a shaft extends. This shaft has a rst cylindrical portion 37 litting the bore 33, a second exteriorly screw threaded portion 38 engaging the thread 32 and a third cylindrical portion 39 of a smaller diameter. A disc shaped body 40 is secured to the shaft portion 39 by means of a set screw 41 and is located interior of and slightly spaced from the outer tubular extension 28 of the pulley 25. A coil spring 42 is located in the space 30, 31 and secured with its one i end in a bore 43 of disc 46 whereas its other end is held to the bottom of space 36 between the extensions 28 and 29 by means of a pin 44 radially penetrating these extensions.

In the member 40 a dowel 46 and a lug or nose 47 of the tubular extension 29, both projecting parallel to the axis of the part 35 may be provided. They serve as an outer positive, non-wedging, stop for the jam-sensing pulley 25 when it is in the extreme jamming position. The aforementioned disc shaft portion 36 of the adapter 35 and the adjacent shaft portion 37 are provided with an axial bore 48, to receive therein the free end of the rotor or armaa ture shaft 49 of an electric motor 50 which may be secured to the frame at 57. In order firmly to connect the shaft 49 to the adapter 35, as clearly shown in FIGS. 4 and 5, the disc portion has a radial tapped hole 52 for the application of a set screw 53. Of course any other suitable and conventional rigid connection between the motor and shaft 35 may be substituted for that shown if so desired. In the illustrated embodiment, the disc portion 36 may be provided similarly to the disc member 40, with a dowel` 54 and the pulley 25 may have a projection or lug 55 as an abutment for the dowel for the purpose of setting a tension preload of the spring 42 if so desired. Dowel 54 and lug 55 also constitute a lost motion connection between the motor and the pulley 25 whereby the latter will be positively taken along when the motor reverses its direction of rotation.

In the electrical circuit of FIG. 6 of the machine to whichvthe jam clearing device is applied, thereare shown the outlets denoted CS of a current source with a double pole switch MS from which one wire 6i) leads directly to one terminal of the motor 50. In the wire 61 leading to the other terminal of the motor a switch with a contact arm 62 is inserted which is part of a time delay relay unit TDR. As such units are on the open market in various designs and operative in various ways, the illustration in FIGS. 6 and 7 is to be understood merely as an example to render the principle intelligible, and all parts are shown in a schematical rather than in a structural manner. Thus the arm 62 is provided with a tension spring 63 against the restraint of which the relay coil 65 when energized pulls the arm 62 in the switch closing position as in FIG. 6. Further connected to arm 62 is the piston of a dash pot 66 whereby the closing of the switch will be delayed a predetermined length of time, e.g. two seconds from the instant an energization of the coil 65 has started. The coil 65 of the time delay relay is connected with its one end to the Wire 60 by means of a branch lead 67. The other end of the coil 65 is connected to a fixed contact point 68 of a limit switch LS. The illustration of the limit switch which is also on the market in various designs, and its parts is to be understood in a similar manner to that stated hereinbefore with respect to the time delay relay. The limit switch further comprises a movable contact arm 69 connected by a branch lead 70 to the wire 61. A compression spring 71 urges the arm in the contacting position in FIG. 6. On the side opposite the spring 71 the arm 69 is connected with a rod-like member 72 provided at its end with a roller 73 which can bear against the rim 74 of the tubular extension 28 of the pulley 25 as more clearly visible in FIG. l. Hence, if in FIG. 1 the tubular extension is shifted to the left hand side as it will be explained hereinafter, the arm 69 in FIG. 6 will be pushed out of contact with the point 68 against the restraint of the spring 71. Should it be desired to provide a signal, be it acoustical or visual, as a Warning when a jam occurs, another contact point 75 may be provided against which the arm 69 can be shifted when it is disconnected from point 68. Point 75 is connected through a wire 76 over a signaling device S to the wire 60.

The device operatesl in the following manner: First of all the direction of the thread 32 should be the same as that of the motor rotation if the motor is directly coupled to the adapter shaft 35, and it is advisable to adjust the spring 42 with some preliminary tension. The parts are assembled as shown in FIG. l, that means, the motor shaft 49 is inserted in the bore 33 of the adapter and the connection between these two parts is secured for common in FIG. 6. This switch is open as there is no current liowing through the coil 65 as long as the main switch is open, and spring 63 of the time delay relay holds the contact arm 62 off the fixed contact 62'. When the main switch is now thrown in, current will oW through wires 60 and 67, through the coil 65, the contact 68, 69, and back to the current source through leads 70 and 61. The energization of the coil 65 will attract contact arm 62 to engage the contact 62 with a short delay, say two seconds, caused by the dash pot 66. Thereby the motor and hence the entire mechanism will be started, pulley 25 driving the shaft 17 by means of the belt 27 and Vpulley 26, and shaft 17 will in turn driveshaft 11 via pinion 24 and gear 23. The spring 42 will transmit the torsion between'the motorshaft and pulley 25 and the latter will take its normal operative position on the screw thread 32 of the adapter 35. Simultaneously, the lug 55 and dowel 54 will have separated, i. e. left their relative positions shown in FIG. 5. This relative position of the parts remains as long as the total mechanism operates normally i.e. under normal load. If, however a jam between a pick-up arm 15 and the ipper blade 20 occurs, e.g. owing to a coil 100 jamming between the two movable parts, a stoppage will occur which the motor tends to overcome. the resistance of the driven parts increases with the result that a relative rotation of the motor to the pulley 25 will take place which owing to the screw thread 32 will cause an axial shift of the pulley towards the left hand side if it is assumed that, looking from that side the motor rotates in an anticlockwise direction. This relative rotation will further tensionthe spring 42 which thus takes up the increased resistance. Simultaneously the axial shift of pulley 25 owing to the engagement of the roller 73 with the rim 74 will open the limit switch LS against the restraint of its spring 71, so that the coil 65 of the time delay relay will be deenergized and the switch 62, 62 will be opened due to the tension of the spring 63. Consequently the motor 50 will be stopped. This is the position of the switches shown in FIG. 7. It will be noticed that the stopping of the armature of the motor will be softened due to the presnce and tensioning of the pulley spring 42. The de-energization of the motor 56 renders it possible for the spring 42 to relax and thereby to reverse the motor armature which had lirst come to a stand still. When then the dowel 54 engages the abutment 55, the motor armature owing to Yits inertia will take kalong the pulley 25 and hence also shafts 17 and 11 and the members connected there with which will also be turned somewhat in the reversed direction. Thereby the blade 20 and the engaged arm 15 will be separated and a jamming coil 100 may be enabled to drop off. As owing to the relaxing of spring 42 pulley 25 will have returnedV in the meantime to its original axial position, `limit switch LS will now be closed again and will re-energize the coil 65 of the time-delay relay so as to close the switch 62, 62 with, however, a delay caused by the dash pot 66. This time interval until the motorris re-energized and starts to rotate again in the normal direction renders it possible in most instances for the jamming coil 100 to fall off so that the jam is cleared and that the whole mechanism can operate normally again. Should, however, the jam not be cleared, stopping of the motor, reversal of the driven parts and restarting of the motor will be automatically repeated until an operator removes the jam by hand. In order to call the operator when his activity becomes necessary the above-mentioned acoustical or visual signal sender S may be provided which as it will be clear from FIGS. 6 and 7 `will be excited each time and as long as the limit switch is opened since in that event current will flow from the one terminal of the current source Y through leads 61 and 70, switch arm 69, contact 75, the

signal transmitter S and back to the current source through leads 76 and 60.

AAlthough I have described only one embodiment of my invention it will be apparent to those skilled in the art Inv consequence.

that many alterations and modifications can be madeof the illustrated structure without departing from the spirit and essence of my invention which for this reason shall not be limited but by the scope of the appended claims.

I claim:

1. In a jam clearing device for a mechanism including an electric motor adapted to be energized for rotation 1n a normal direction, a torque control device includinga spring tensioned increasingly as the torque through said device increases, said device being instrumental to deenergize said motor when the torque reaches a predetermined maximum, and driven parts susceptible of being jammeda shaft adapted to be rigidly connected to the rotor of said motor, a member connected to said driven parts and to said shaft through said torque control device, a lost motion connection between said shaft and said member and being operative to reverse said driven parts whenthe rotation of said shaft is reversed by said spring relaxing upon deenergization of said motor, and a time delay arrangement adapted to cause reenergization of said motor a predetermined length of time after the motor has started to reverse the direction of rotation.

2. In a jam clearing device for a mechanism including an electric motor adapted to be energized for rotation in a normal direction, a torque control device including a spring tensioned increasingly as the torque through said device increases, said device being instrumental to deenergize said motor when the torque reaches a predetermined maximum and driven parts susceptible of being jammed, a shaft adapted to be rigidly connected to the rotor of said motor, a member connected to said parts and to said shaft through said torque control device, a lost motion connection between said shaft and said member and being operative to reverse said driven parts when the rotation of said shaft is reversed by said spring relaxing upon deenergization of said motor, a time delay relay including a iirst switch in an energizing circuit for said motor in series therewith and open when said motor is not energized, electric means in a circuit parallel to the motor energizing circuit for closing said switch, means for delaying the closing of said switch upon energization of said electric means, a second switch being a normally closed limit switch in series connection with said electric means, and other means responsive to a. movement of a part of said torque control device due to an excessive torque thereby to open said limit switch.

3. In a jam clearing device for a mechanism including an electric motor and driven parts susceptible of being jammed, a shaft adapted to be rigidly connected to the rotor of said motor, a torque transmitting spring, a member connected to said parts and to said shaft through said torque transmitting spring so as to be driven by said shaft when the latter is rotated by said motor in a predetermined normal direction, a lost motion connection between said shaft and said member and being inoperative when said motor rotates in the normal direction and operative when the rotation of said shaft is reversed due to a relaxing of said spring, an element movable in response to a change of the tension of the torque transmitting spring, a time delay relay including a first switch in an energizing circuit for said motor in series therewith and open when said motor is not energized, electric means in a circuit parallel to the motor energizing circuit forY closing said switch, means for delaying the closing of said switch, a second switch being a normally closed limit switch in series connection with said electric means, and other means responsive to a movement of said element due to an excessive torque thereby to open said limit switch, whereby upon the occurrence of an excessive torque said motor will be de-energized and reversed due to the relaxing of said torque transmitting spring, and by its inertia will take said member along through said lost motion connection until said inertia has been spent, whereupon due to a reversal of the movement of said element said limit switch will be closed again so as to energize said electric means and to cause thereby a delayed closing of said first switch and reenergization of said motor.

4. In a torque control device, the combination of a driving shaft adapted to be connected with one of its ends to a prime mover having a predetermined normal direction of rotation, said shaft having an externally screw threaded portion, a rotatable driven member having an interiorly screw threaded portion in engagement with the threaded portion of said shaft, said screw threads turning in the direction of the normal rotation of said shaft, a torsion spring encompassing said threaded portions and being endwise connected to said shaft and to said member, one of said portions, by its axial movement due to a change of the spring tension, being adapted to cause a deenergization of said prime mover upon the occurrence of an excessive torque transmitted by said spring, and a lost motion connection between said shaft and said driven member and being inoperative when said shaft rotates in the normal direction and operative when said shaft rotates in the opposite direction.

5. In a torque control device, the combination of a driving shaft adapted to be connected to a prime mover having a predetermined normal direction of rotation, said shaft including a first disc-like portion at its connected end, a cylindrical portion, an exteriorly screw threaded portion with the thread turning in the normal direction of rotation of said shaft, and a second disc-like portion at the opposite end; a pulley axially and peripherally movable on said cylindrical shaft portion, said pulley including a longer outer and a shorter inner tubular lateral extension with a free space therebetween, said inner tubular extension being interiorly screw threaded and in engagement with said thread of said shaft; a torsion spring within said space and being endwise connected to said second disc and said tubular extensions, abutments between said second disc and said inner tubular extension, projections on both said pulley and said first disc, respectively, on the sides facing each other so that the one projection can sideways bear against the other projection upon a turning of said shaft in the opposite direction but will be disengaged from said other projection when said shaft rotates in the normal direction.

6. In a torque control device, the combination of a driving shaft adapted to be connected to a prime mover of a predetermined normal direction of rotation, a driven member, a torsion spring connected between said shaft and said driven member, an element movable in response to a change of the tension of the torsion spring and adapted to cause a deenergization of said prime mover upon the occurrence of an excessive torque transmitted by said spring, said shaft including a disc rigidly connected thereto, said driven member being wheel-like shaped and facing said disc, projections on both said member and said disc, respectively, on the sides facing each other so that the one projection can sideways bear against the other projection upon a turning of said shaft in said opposite direction but will be disengaged from said other projection when said shaft rotates in the normal direction whereby said projections establish a lost motion connection between said shaft and said driven member and being inoperative when said shaft rotates in the normal direction, and operative when said shaft rotates in the opposite direction.

References Cited in the file of this patent Melmer Jan. 24, 1939

Claims (1)

1. 3. IN A JAM CLEARING DEVICE FOR A MECHANISM INCLUDING AN ELECTRIC MOTOR AND DRIVEN PARTS SUSCEPTIBLE OF BEING JAMMED, A SHAFT ADAPTED TO BE RIGIDLY CONNECTED TO THE ROTOR OF SAID MOTOR, A TORQUE TRANSMITTING SPRING, A MEMBER CONNECTED TO SAID PARTS AND TO SAID SHAFT THROUGH SAID TORQUE TRANSMITTING SPRING SO AS TO BE DRIVEN BY SAID SHAFT WHEN THE LATTER IS ROTATED BY SAID MOTOR IN A PREDETERMINED NORMAL DIRECTION, A LOST MOTION CONNECTION BETWEEN SAID SHAFT AND SAID MEMBER AND BEING INOPERATIVE WHEN SAID MOTOR ROTATES IN THE NORMAL DIRECTION AND OPERATIVE WHEN THE ROTATION OF SAID SHAFT IS REVERSED DUE TO A RELAXING OF SAID SPRING, AN ELEMENT MOVABLE IN RESPONSE TO A CHANGE OF THE TENSION OF THE TORQUE TRANSMITTING SPRING, A TIME DELAY RELAY INCLUDING A FIRST SWITCH IN AN ENERGIZING CIRCUIT FOR SAID MOTOR IN SERIES THEREWITH AND OPEN WHEN SAID MOTOR IS NOT ENERGIZED, ELECTRIC MEANS IN A CIRCUIT

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