US2210591A - Baling press - Google Patents

Description

A118. 1940- e. w. LANGFORD n AL 2,210,591

BALING PRESS Filed lay 5, 1937 2 Sheets-Sheet 1 FIG.2.

llll IIHH HIIIIIH IIHUHH HHHHI HHH INVENTORS GEORGE W.LANGFORD BY ALFORD c. BARROWS W Away/J15 ATTORNEYS g- 1940. G. w. LANGFORD El AL 2 0, 1

BALING PRESS Filed May 5, 1937 2 Sheets-Sheet 2 FIG.3.

NORMALLY CLOSED LIMIT SWITCH Patented Aug. 6, 1940 STATES Tsar BALING PRESS Application May 5,1937, Serial No. 140,933

4 Claims.

Figure 3 is a diagram of the electric circuitsj Figure, 4 is an elevation of the brake for looking the mechanism from operation;

Figure 5 is a diagram showing the characteristic curves of the special motor as compared with a standard motor.

Baling presses are used for various purposes, among which are the compacting of loose material, such for instance as paper scraps, paper cartons, etc., into a dense mass; also, the compacting of cotton and other fibrous material. In the performance of this work, the initial movement of the platen or compression plunger meets with very little resistance, but the load progressively builds up until for the final compression an exceedingly high pressure is required. Furthermore, to secure the greatest efficiency, the speed of operation should be progressively decreased. This is for the reason that a very large portion of the lead is due to the compression of air trapped in the interstices and which must be permitted to escape prior to the final compression. It is also desirable to perform the total operation in as short a time as possible, consistent with the expenditure of a reasonable amount of power. In view of these conditionsan ideal operation would be one in which the platen or compression plunger is initially moved at a relatively high velocity with a relatively small expenditure of energy and is progressively deceler ated with increased power in accordance with increase in load. Various constructions have been devised to more or less approximate such operation, but such constructions involve complication in the mechanism. Also, it has been considered necessary to employ an irreversible mechanism, such as a worm gearing, for moving the platen so that the load will be held when the power is released. This involves high frictional losses and proportionally increases the power required for the operation of the machine.

With our invention we have accomplished thev desired result by an exceedingly simple construction and'one in which the frictional losses are reduced to the minimum. Essentially, this improved construction comprises an electric motor having an exceedingly large range of variation in speed and power with the characteristic of very low torque and low consumption of energy at high speed, and progressively decreasing speed and increasing torque in proportion to increase in load. While it is true that most electric motors have this characteristic, to some extent, for the purpose of our invention it is necessary to have a large range, as for example a variation in speed from 1800 R. P. M. to under 400 R. P. M.; a variation in torque from zero at high speed to 100 foot pounds at zero speed; and a variation in current consumption at 220 volts of from 6 amperes to amperes. Another feature of our improvement is that we have dispensed with an irreversible transmission intermediate the motor and platen actuating means, and also avoid the use of a variable speed transmission or other complication. In place of these, we employ a simple step-down gearing which operates with very low frictional losses. A third feature of our improvement is the automatic arresting of movement at some predetermined load by automatically ole-energizing the motor. feature is the holding of the mechanism from reverse movement by the automatic and instantaneous locking of the same whenever the electric motor is ole-energized.

As our improvements are applicable to various types of baling presses we deemed it unnecessary to illustrate the construction further than the movable platen and the mechanism for actuating the same. i

As shown in Figures 1 and 2, A is the movable platen which is drawn upward in the compression chamber (not shown), by means of chains B passing over sprocket Wheels 0 upon aligned driven shafts D and D. These shafts are actuated from the motor E through the medium of a step-down reversible driving train including reduction gears inclosed within a housing F for operating a pinion G which is in mesh with a large gear 1-]: upon a shaft I. On this shaft are pinions J and J which respectively intermesh with gear wheels K and K upon the shafts D and D. The shaft E of the motor E extends outward from the end opposite the transmission F into operative relation with an automatic brake L which as hereinafter described will lock said shaft from movement whenever the motor is deenergized. 3

Still another The motor E has the characteristics above referred to and its controlling circuits are illustrated in the diagram, Figure 3, as follows:

The motor is preferably of the multi-phase type and as shown is a three-phase motor. I, 2 and 3 are the leads extending to a reversing switch M. This switch is manually controlled by pushbutton switches 4, 5 and 6, and is automatically controlled by limit switches I and 8 and an overload switch 9. The push-button switch 5 is nor mally opened and when closed starts the compression. from the lead 2 extending to the normally closed switch 6 and then to the switch 5. Beyond the switch 5 is a conductor II which extends to a relay l2 for closing the contacts I3, l4 and 15 of the reversing switch M for driving the motor in a forward direction. From the relay l2 a conductor 16 extends to the limit switch I and thence through a conductor l8 to the lead 3 which completes the circuit. The push-button switch 4 is also normally opened and when closed returns the movable platen to its initial position. Its circuit includes the conductor l and normally closed switch 6. A conductor l9 leading to a relay 2!! for operating the movable contacts 2|, 22 and 23 of the reversing switch M to operate the motor in the reverse direction. From the relay 20 a conductor 24 extends to the limit switch 8 and thence through the conductor I 8 to the lead 3. The push-button switch 6 is in multiple series with the push-button switches 4 and and includes the circuits previously described in connection therewith. When the relay I2 is operated to close the contacts l3, l4 and i5 the leads l, 2 and 3 will be connected respectively thereto through conductors 25, 26 and. 21, and through conductors 28, 29 and 30 with the motor E. The conductor 29 includes the coil 3| of the over-load switch 9. When the relay 20 is operated the closing of the contact 2! will connect the lead I with the conductor 30, through the medium of a conductor 32. The contact 722 will connect the lead 2 with a conductor 29 through the medium of a conductor 33 and the contact 23 will connect the lead 3 to the'conductor 23 through the medium of a conductor 34. Thus, it will be understood that the press may be started in operation by the push-button switch 5 and that the motor will continue to rotate in a forward direction until its circuit is broken, either through the operation of the limit switch I or the over-load switch 9. On the other hand, operation may be manually arrested at any time by the push-button switch 6, and after the completion of the operation the platen can be returned by the operation of the switch 4 which drives the motor in reverse direction until it is automatically de-energized through the operation of the limit switch 8.

As above stated, it is essential to lock the mechanism whenever the motor is de-energized so as to avoid the reverse driving of the same by the expansive force of the compressed material. For this purpose we employ a brake L which engages a brake drum L mounted directly upon the motor shaft extension E of the motor E. This brake must be instantaneously released whenever the motor is energized to drive the same either in a forward or reverse direction, and also it must be instantaneously applied when the motor is de-energized. This as shown, we have accomplished by a solenoid L which as shown in the diagram, Figure 3, is included in shunt with the conductors 28 and 30 of the motor. This Its circuit includes a conductor l0 coil is, therefore energized whenever the motor circuit is closed and is de-energized upon the opening of such circuit. As specifically illustrated, the brake has a pair of brake shoes L and L which are connected to each other through toggle levers L and L, the former having an extension arm L which is connected with a movable core L of the solenoid. The core L is normally withdrawn by the operation of a spring L which moves the shoes toward each other and into frictional engagement wtih the drum L. When, however, the coil L is energized which occurs simultaneously with the closing of the motor circuit the core L will be drawn downward against the tension of the spring L and the shoes L and L will be separated to release the drum L. A spring L forms a resilient element between the toggle lever L and the shoe L and a nut L serves to adjust the tension of said spring.

From the description above, the operation of our improved press wil be understood, and we have found that by eliminating the irreversible transmission intermediate the motor and the platen operating means we can cut down the power of the motor substantially 50%. This does not involve any lessening of the maximum compression pressure, or increase in time required for the complete operation. On the contrary, our improved construction is more expeditious in its operation for the speed is determined solely by the load. As a specific case, the total reduction gearing between the motor and the sprocket shafts D may be a ratio of 225 to 1 and because of this great reduction a comparatively small powered motor will furnish the maximum pressure required. Nevertheless, the high speed of operation when relieved of load or under slight load will cause a fairly rapid movement of the platen and this is retarded only to the extent that is necessary to permit the escape of entrapped air and to furnish the necessary pressure at each point in the operation. If desired, the press may be controlled from a more or less remote point or, if desired, from a plurality of different points by an extension of the control circuits to such points. Thus, as indicated in Figure 3, N indicates a single point of control and the dotted lines 0 and P represent two different points of control which may be alternatively used.

A motor having the characteristics above described and which we designate baler motor, may be designed in various ways, but the following shows one specific design in comparison with a five horsepower squirrel cage type of induction motor.

Thus it will be noted that while the frame and mechanical parts of the two motors are substantially the same, there is a radical difference between the two in electrical organization. Figure 5 shows in full lines the characteristic torque and ampere curves of the special baler motor, and in broken lines similar curves of a standard motor, and it will be noted that whereas the standard motor attains its maximum torque at 88% of synchronous speed, the baler motor increases in torque with decrease speed from 100% to zero. This is advantageous not only on account of the increase in torque for final compression of the bale, but also because the decrease in speed gives time for the escape of entrapped air which constitutes a large part of the load.

What we claim as our invention is:

1. In a baling press, the combination with a compressor platen and mechanism for moving the same, of an alternating current electric motor characterized by a decrease in speed and increase in torque in proportion to load operable through a relatively wide range of variation of the order of from 100% to less than 25% in speed With continuous torque increase, and a relatively low friction high constant ratio step-down transmission between said motor and mechanism.

2, In a baling press, the combination with a compressor platen and mechanism for moving the same, of an alternating current electric motor characterized by a decrease in speed and increase in torque in proportion to load operable through a relatively wide range of variation of the order of from 100% to less than 25% in speed with continuous torque increase, a reversible non-locking relatively low friction high constant ratio step-down transmission between said motor and mechanism, and means for locking said motor from reverse movement.

3. In a baling press, the combination with a compressor platen and mechanism for moving the same, of an alternating current electric motor characterized by a decrease in speed and increase in torque and current consumption in proportion to load operable through a relatively wide range of variation of the order of from 100% to less than 25% in speed with continuous torque increase, a relatively high constant ratio reversible non-locking step-down transmission between said motor and mechanism, an automatic cut-out for the motor circuit operated by a predetermined maximum current volume therein, a brake for automatically locking said motor and holding the load, and electromagnetic means for releasing said brake in a circuit controlled by said cut-out, whereby the opening of the motor circuit and de-energizing of the motor will instantaneously apply said brake.

4. In a baling press, the combination with a compressor platen and mechanism for moving the same, of a high constant ratio step-down transmission for operating said mechanism, and an alternating current electric motor characterized by a decrease in speed and increase in torque in proportion to load operable through a relatively wide range of variation of the order of from 100% to less than 25% in speed with continuous increase in torque, said motor being adapted to operate at maximum speed minimum torque and minimum current consumption during the initial movement of said platen and being responsive to increase in load due in part to entrapped air to decrease the speed so as to give time for the escape of said entrapped air with a continuous increase in torque throughout the entire movement of the platen. I

GEORGE W. LANGFORD. ALFORD C. BARROWS.

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