US3890547A

US3890547A - Speed control device

Info

Publication number: US3890547A
Application number: US239927A
Authority: US
Inventors: Norman Keck
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-03-31
Filing date: 1972-03-31
Publication date: 1975-06-17
Anticipated expiration: 1992-06-17

Abstract

In a machine where a flexible material is passed consecutively through two sections of a machine, a device for controlling the speed at which the material is passed through one of such sections to correspond with the speed at which the material is passed through the other of these sections, including a series of mercury switches mounted on a structure which is tilted in response to the position of a loop of material between the sections, the tilting movement serving to actuate the switches to affect a network associated with a motor to cause the motor to increase or decrease the speed of the material through the one section of the machine as is called for by the extent of the tilting movement.

Description

United States Patent Keck 1 1 June 17, 1975 1 SPEED CONTROL DEVICE 3,672,600 6/1972 Carlson 318/6 [76] Inventor: jNcplli'gtiafilKggliggO7 Fourth Ave., Primary Emmner B Dobeck Attorney, Agent, or FirmCar1 C. Batz [22] Filed: Mar. 31, 1972 Appl. No.: 239,927

[57] ABSTRACT In a machine where a flexible material is passed consecutively through two sections of a machine, a device for controlling the speed at which the material is passed through one of such sections to correspond with the speed at which the material is passed through the other of these sections, including a series of mercury switches mounted on a structure which is tilted in response to the position of a loop of material between the sections, the tilting movement serving to actuate the switches to affect a network associated with a motor to cause the motor to increase or decrease the speed of the material through the one section of the machine as is called for by the extent of the tilting movement.

4 Claims, 7 Drawing Figures PATENTEUJUH 17 ms SHEET FIG.2

PATENTEDJIJN 1 1 ms 547 mm {a 46 V 48 ill r== V FIGA 1 SPEED CONTROL DEVICE This application relates to a device for regulating the speed of material being passed through one section of a machine in accordance with the speed of this material in another section of the machine and more particu larly to such a device which is sensitive to the depth of the loop formed by the material as it passes from section to section.

BACKGROUND There are many situations in industry where a flexible sheet material such as paper, cloth or the like are passed through different sections of machinery and where the speed at which such material is passed through one of such sections may vary from the speed at which it is passed through another section. It would be highly desirable in such situations to regulate the speed at which the material is passed through the other section to correspond with the speed at which it is passed through the one section so that the material does not either pile up or come into undue tension between the sections.

In speaking of a machine" I include the separate mechanisms through which the material is passed continuously, however separated those mechanisms may be.

I am aware of attempts which have been made in the past to solve this problem of variable speed by the provision of devices having levers which contact the loops of material between sections using rheostats arranged to be operated by the levers thus to cause the speed of a driving motor to be increased so as to take up the additional slack when the speed of the material in a previous section is increased. However, an objection to such arrangement is that the friction involved in operating the rheostat is too great to be operated by anything which is only in lightly touching contact with the mov ing loop of material between the sections. Another objection is that the mechanisms needed for the actuation of such rheostats become mechanically complex and cumbersome, requiring special constructions and the use of non-standard electrical units.

It is therefore an object of this invention to provide a device for coordinating the speed of a material through a section of a machine with the speed at which the material is being passed through another section of the machine and to accomplish this in an effective way using standard parts and without the use of complicated or complex mechanisms. A further object is to provide such a device which will sense the depression of the material between sections with a light touch and which at the same time will positively operate to change the speed ofa driving motor for one section so as to coordinate it with the speed of the material being passed through the other section. Still another object is to provide such a device which can be easily adjusted for operation within the ranges of control which are desired and which will automatically bring the speeds of the two sections into equalization. Other objects and advantages of the invention will be apparent as this specification proceeds.

SUMMARY OF THE INVENTION In the device of my invention I provide a tiltable structure on which is mounted a switch, or preferably a series of switches, which may be of the mercury contact type, the switches being mounted with an angu- Iar orientation such that upon tilting of the structure to l one of the switches is actuated and upon tilting ofthe structure to a greater degree another of the switches is actuated, all without changing the position of the mercury tube of the switch with respect to the structure on which it is mounted. A further explanation of this feature will be given in the detailed description of my de- VlC}.

DETAILED DESCRIPTION Certain embodiments of my invention are illustrated in the accompanying drawings in which:

FIG. 1 is a schematic illustration of one type of machine where coordinating of speeds is needed and showing my improved device in a side elevational view;

FIG. 2 is a top view of the improved device illustrated in FIG. 1;

FIG. 3 is a detail view of one side of the disc showing the switches mounted thereon;

FIG. 4 is a detail view of the other side of the disc showing resistors mounted thereon;

FIG. 5 is a circuit diagram showing the electrical units connected to form a network which can be connected in the shunt circuit of an electric motor;

FIG. 6 is a top view of a modified form of the inven' tion; and

FIG. 7 is a side elevational view of the modifications shown in FIG. 6.

As illustrated in FIGS. 1-5 there is shown a section 1 ofa machine whichincludes rolls l0 and 11 between which a flexible sheet I2 is passed in the direction of arrows 13. After passing from section I the flexible material falls downwardly to form a loop 14, the other side of which passes upwardly and into section 2 of the machine. A motor M drives roll 15 to pass the material onwardly in section 2.

The device for coordinating the speeds of the material in the different sections includes the base 16 on .which are mounted

bearings

17 and 18 which contain the shaft 20. Secured to shaft 20 is a member 21 which includes one or more finger pieces 21a extending transversely of the shaft. This member is arranged to contact the lowermost points of the loop so that when moved up and down through contact with the lower part of the loop member 21 it serves to turn the shaft 20 clockwise (as seen in FIG. 1) when the loop is deepened, and to turn the shaft counter-clockwise as the bottom of the loop raises.

To counter-balance the weight of the member 21 and to press this member into very light contact with the bottom of the loop I provide the counter-balancing arm 22 which is secured to shaft 20 and extends transversely from shaft 20 in a direction opposite to that of member 21. A weight 23 is mounted on arm 22 and is adjustable along the length of the arm as may be necessary to give a slight upward pressure by the member 21 against the bottom of the loop.

The disc 30 is secured to an end of shaft 20 by means of the collar 30a and bolts 30b. This disc may be circular or of other configuration and serves as a convenient place on which to secure the mercury switches on the tiltable structure. The disc contains apertures 30c through which wires may be passed from one side of the disc to the other, and tapped holes in which screws 300' may be passed to mount the switches on the disc. In FIG. 3 the switches are shown schematically and are designated 31, 32, 33 and 34. These switches are shown merely as straight tubes in FIG. 3, but they may be any standard switch which is designed to make or break contact upon being tilted to a certain angle and respectively to make or break contact when tilted back beyond this angle, and they make take various exterior forms and specific internal constructions. Suitably, they may be of the type 1-12, K-lS, T-l 2 or L-30 marketed by the Powerex Switch Company of Watertown, Massachusetts.

The switches 31-34 may be mounted at any convenient location on disc 30, and it is the angle at which the switch is disposed which is of significance in the operation of the device; that is, the angle which the axis of the switch makes with the horizontal. As shown, the switch 31 is mounted using a band 31a which is secured by a screw 30d. Since only a single screw is used the screw may be loosened to permit the switch to be turned about the screw pivot to the desired angular position and then tightened to hold it in this position. The

other switches

32, 33 and 34 may be mounted in a similar fashion.

Some types of mercury switches are designed to make contact when the glass tip is lowermost, and some are designed to make contact when their base part is lowermost. Either type can be used in the present invention. The connection from each of the switches may be by wires passed through the perforations 30c nearest the switch. The important thing is that the switch make its contacts with a minimum of resistance when tilted and when its axis makes a certain predetermined angle with the horizontal, and that it just as easily breaks its contacts when tilted back beyond this angle.

On the inner side of the disc 30 (FIG. 4) two

resistor strips

35 and 36 are mounted each with connections at their ends and a variable connection at an intermediate point making, in effect, four resistors designated respectively 37, 38, 39 and 40. The variable center connection 4] permits increase of the resistor 37 and decrease of the resistor 38, and vice versa', and the variable center connection 42 permits increase of the resistor 40 and decrease in the resistor 39, and vice versa. The

terminals

43 and 44 of the network of switches and resistors are connected by a cable, as more clearly shown in FIGS. 2 and 4, which is loosely led to a median position on shaft 20 where the cable is coiled about the shaft, with the connecting

wires

45 and 46 being led to

terminals

47 and 48. By coiling the cable about the shaft l eliminate bending of the wires at any certain point through the turning of the shaft.

The electrical connections are illustrated more particularly in FIG. which shows a setup in which my switch and resistor network is adapted for connection in, for example, a shunt field circuit of a motor. This motor may be the direct current motor M of FIG. 1 which is arranged to drive the material in the second section of the machine.

The resistors 37-40 may be thought of as being connected in the network circuit with the switches 31-34 connected in shunt fashion across the respective resistors so that when the contacts of any switch are made this serves to short out the resistor across which it is connected, and when the contact of any switch is open, the respective resistor is effective in the circuit.

When the switches and resistors have been mounted on disc 30 and connections made as indicated in FIG. 5, it is necessary to set the switches 31-34 in the desired angular positions. If the sensing member 21 is movable through a range of, for example, 45 and is therefore capable of tilting the disc 30 through 45 the switch 31 may be positioned so that it will make contact when the disc and the switch are tilted through the angle which in FIG. 3 is designated A (for example, 5). Switch 32 may be positioned so that it will make contact when tilted through the angle B (for example, 20); switch 33 to make contact when tilted through 35; and switch 34 positioned to make contact when tilted through 45. Angles A, B, C and D are the angles through which the tiltable structure and the switches must respectively be moved to be brought to the position where changes between the make and break positions take place.

OPERATION We may assume that our control network of switches and resistors is connected at

points

49 and 50 in the shunt circuit of the motor M and that the switches have their contacts in the made or closed condition, and that the sensing member 22 of the tiltable structure is in its upper position with no pressure from the sheet material being passed through the machine.

When the machine is put in operation, the material is passed through

sections

1 and 2 and forms the loop 14 between the sections. At this point the operator may adjust the rheostat 52 to drive the material through section 2 of the machine at the average or approximate speed of its passage through section 1.

When for some reason the speed of the material through section 1 is increased, the loop 14 comes to bear down at its bottom point on the sensing member 21 and to press this member downwardly producing tilting of the tiltable structure of which it is a part, thus causing disc 30 and the switches thereon to move angularly about shaft 20; and after 5 has been passed the switch 31 changes its contacts to open position. Up to this point none of the resistors 37-40 were active in the network circuit because of having been shorted out by the switches 31-34 which had their contacts in closed position, but now with switch 31 in open position the short about resistor 37 is eliminated and this resistor is brought into effectiveness in the shunt circuit of motor M which serves to increase the speed of the motor driving the material through section 2 of the machine. If this effect is not sufficient to equalize the speeds of the material passing through the two sections, and the bottom of the loop presses the sensing member down further, tilting the disc and switch 32 through an angle of 20, this causes switch 32 to change to open position thus removing the short about resistor 38 to bring resistor 38 effectively into the shunt circuit as well as resistor 37. This serves to further increase the speed of the motor. The same action takes place, if needed, with respect to switch 33 and resistor 39, and with respect to switch 34 and resistor 40. Assuming that the range of the control has been properly seclected, there will be a point at which the increase of speed of the material in the second section will be sufficient to equalize the speeds in the two sections. As previously stated, this range may be selected through operation of the rheostat 52 and the rheostat 53 may be utilized to regulate the sensitiveness of the automatic control.

Should the speed of the material through section 1 decrease, the reverse action will take place. The sensing member 21 will then raise to the critical angle for again closing the switch which was last to be opened causing a resistor to be cut out thus slowing the motor M to some extent. When the tilting action goes further to cause the closing of the next switch in line a further slowing of the motor takes place. Thus the increases and decreases in the speed of material through section 1 of the machine are made to produce corresponding increases and decreases in the speed at which the material is passed through section 2 of the machine.

In the embodiment illustrated the material is passed through section 1 on the left to section 2 on the right, but the same result may be accomplished if the material were being passed from right to left in which case the feeding of the material through the section 2 would be adjusted in accordance with the passage of the material through section 1.

As above explained, the connection of my switch and resistor network is connected in the shunt circuit of a DC. motor and the effect of cutting out a resistor serves to slow the motor and to cut it back in serves to speed the motor. If this network were connected in the main motor circuit instead of the shunt circuit, the opposite would be true and adjustment for operation affecting the main circuit of the motor could be made merely by bringing each of the registors 37-40 through 180.

Another feature of the invention is that the

connectors

41 and 42 may be placed in the center of the resistance strips 35 and 36 which would have the effect of making each resistor 37-40 of the same value, tending to make each increment of speed change about the same. Or, on the other hand, the connector 41 for example could be moved to the left as shown in FIG. 5 to decrease the value of resistor 37 and increase the value of resistor 38, which would have the effect of decreasing the effect of the first increment of change while increasing the effect of the second increment. The same may be said of the connector 42 with respect to the third and fourth increments of speed change.

Further, it should be understood that while as indicated in FIG. 5 switches 31-34 are set to change contact when their axis is tilted respectively through angles A, B, C, and D with the horizontal, and it is explained that these angles may be respectively 5, 35 and 40, these angles may be selected as desired to bring on an increment of speed adjustment in response to a slight movement of the tiltable structure or in response to a greater movement of the tiltable structure. Also it is shown in FIG. 5 that the switches are located in regular sequence and angularly spaced about the axis of disc 30, but the switches may be in any sequence at at any convenient radial or angular distance about shaft 20. Further, the connections between the switches and the resistors may be interchanged if desired; that is, switch 31 may be connected across resistor 39 and switch 32 across 37, for example. A change of this kind could be made in adjusting the amount of change in speed which is effected at each increment of change.

It is usually desirable to attempt the control so that there is a balance of speeds in the two sections of the machine at about the center of the angular range of movement of the tiltable structure. To accomplish this the

resistors

37 and 40 as shown in FIG. 5 may be of larger value than

resistors

38 and 39, and this is one of the preferred settings of the device. This setting serves to send the control positively toward the center of the range with the smaller increments of change at the switches which are operable at the intermediate angles of the range.

Although as described four switches 31-34 and four resistors 37-40 are employed, there may be any number of such switches and resistors from one to four or five or more. The substantial advantage of the invention is obtained by using two or more of such switches and resistors, which may be referred to as a series of switches or a series of resistors.

Although in the embodiment just described resistors 37 to 40 are employed, these resistors could be re placed by inductances and the network, including the inductances, utilized in the circuit of an alternating current motor; or, the resistors could be replaced with both inductance and resistance. In this description and appended claims we use the term impedance to cover either inductance or resistance or both.

Another embodiment of my invention is illustrated in FIGS. 6 and 7 where a flexible sheet material 60 is passed between rolls 6] and 62 of section la of a machine and then through

rolls

63 and 64 of section 20 of the machine. In this case, it is desired not only to run the material through section 2a at speeds corresponding with the speed at which it is passed through section 1a, but to maintain the material between the sections in tension.

As the material passes from section In to section 20 it will sag at least to some extent, depending on the tension. In this case my device may include a roll 65 secured to shaft 20a which has ends extending within slots 66 in the frame guide 67. Secured on one end of shaft 20a is the disc 30a which is identical to or similar to disc 30 of the previously described embodiment, with switches mounted on one side and resistors on the other. The ends of shaft 200 are arranged to move up and down within slots 66 of the frame and the roll 65 rests on the sheet material 60 as it passes from section 10 to section 20.

Referring more particularly to FIG. 7, there is provided a spring arrangement restraining the roll 65 against rotation due to frictional engagement with the moving sheet material. This arrangement has a flexible cord 69 which at its upper end is secured to pulley 68 which in turn is secured to shaft 20a and at its lower end is connected with the upper end of spring 70. The lower end of spring 70 is connected with the bracket 71 secured to the same base as frame members 67.

The switches and resistors on disc 30a may be connected as described in connection with the previously described embodiment to a motor which drives rolls 63-64.

The frictional contact between roll 65 and the moving sheet material 60 will tilt the roller 65 and disc 300 until spring 70 exerts the force in holding the tiltable structure which is equal to the force exerted due to frictional engament between the sheet material and the roll tending to tilt this structure.

As the speed of the material passing through section la increases, this lowers the tension in the material between the sections and permits greater sag with lowering of the tiltable structure, the ends of the shaft moving downward in slot 66. This reduces the force exerted by spring 70 and allows the disc to tilt to a greater angle which, as previously explained, results in speeding up the motor, driving rolls 63-64 to equalize the speed of the sections, and increase the tension, causing roll 65 to raise. Thus a balance is brought into effect which tends to bring the sag and the tension of the material moving between the sections to a desired value.

It may be observed that the sagging contour of the moving material in the embodiment of FIGS. 6 and 7 forms what may be called a loop as was described in the prior embodiment, and the vertical position of the bottom portion of the loop of material as shown in FIG. 7 governs the operation of the tiltable structure as does the vertical position of the bottom portion of the loop shown in FIG. 1.

While this invention has been described and exemplifled in terms of certain preferred embodiments, those skilled in the art will appreciate that the invention make take other embodiments and that variations and modifications may be made without departing from the spirit and scope of the invention.

What is claimed is:

1. In a machine wherein a flexible material is passed at varying speeds through one section of the machine and also through another section of the machine with said material sagging between said sections to form a loop, said machine having a device coordinating the speed of said material in each of said sections, the improvement in said device comprising a titltable structure, a switch on said tiltable structure, said switch being of the type which shifts between making contacts and breaking contacts when its axis is tilted to a predetermined angle with the horizontal, said switch being adjustably mounted on said structure to permit adjustment by tilting said switch with respect to said tiltable structure, means sensitive to the extent said material sags between said sections for tilting said structure, and means sensitive to a shift of said switch upon the tilting of said switch to bring its axis to said predetermined angle for changing the speed of said material through one of said sections to bring the speed of said material in said sections more nearly into equilibrium, said ma chine including a plurality of said switches mounted on said tiltable structure each separately tiltable with respect to said structure, each of said switches being separately adjustable to permit tilting of the switch with respect to said structure, said sensitive means being effective to tilt said structure to a predetermined angle to operate one of said switches when said material sags to one extent and to tilt said structure to operate another of said switches when said material sags to a greater extent, and means sensitive to the operation of said other switch for changing by a second increment the speed at which said material passes through said one section to thereby bring the speed of said material in said sections still more nearly into equilibrium.

2. A machine as set forth in claim I wherein each of said switches is a mercury switch, the machine including a band about each of said switches having an opening therein, and including a screw extending through each of said openings and into said structure, each of said screws being seperately turnable one way to loosen one of said switches for tilting the switch about the axis of the screw and the other way to again tighten the switch to said structure.

3. In a machine wherein a flexible material is passed at varying speeds through one section of the machine and also through another section of the machine with said material sagging between said sections to form a loop, said machine having a device coordinating the speed of said material in each of said sections, the improvement in said device comprising a tiltable structure, a switch on said tiltable structure, said switch being of the type which shifts between making contacts and breaking contacts when its axis is tilted to a predetermined angle with the horizontal, said switch being adjustably mounted on said structure to permit adjustment by tilting said switch with respect to said tiltable structure, means sensitive to the extent said material sags between said sections for tilting said structure, said means including a roller member which rests on the top surface of said material and in frictional engagement with said material, said titltable structure being mounted on said roller for rotation therewith.

4. A machine as set forth in claim 3 including a guide structure for holding said tiltable structure against movement longitudinally of said material, but permitting said tiltable structure to move vertically.

Claims

1. In a machine wherein a flexible material is passed at varying speeds through one section of the machine and also through another section of the machine with said material sagging between said sections to form a loop, said machine having a device coordinating the speed of said material in each of said sections, the improvement in said device comprising a titltable structure, a switch on said tiltable structure, said switch being of the type which shifts between making contacts and breaking contacts when its axis is tilted to a predetermined angle with the horizontal, said switch being adjustably mounted on said structure to permit adjustment by tilting said switch with respect to said tiltable structure, means sensitive to the extent said material sags between said sections for tilting said structure, and means sensitive to a shift of said switch upon the tilting of said switch to bring its axis to said predetermined angle for changing the speed of said material through one of said sections to bring the speed of said material in said sections more nearly into equilibrium, said mAchine including a plurality of said switches mounted on said tiltable structure each separately tiltable with respect to said structure, each of said switches being separately adjustable to permit tilting of the switch with respect to said structure, said sensitive means being effective to tilt said structure to a predetermined angle to operate one of said switches when said material sags to one extent and to tilt said structure to operate another of said switches when said material sags to a greater extent, and means sensitive to the operation of said other switch for changing by a second increment the speed at which said material passes through said one section to thereby bring the speed of said material in said sections still more nearly into equilibrium.

2. A machine as set forth in claim 1 wherein each of said switches is a mercury switch, the machine including a band about each of said switches having an opening therein, and including a screw extending through each of said openings and into said structure, each of said screws being seperately turnable one way to loosen one of said switches for tilting the switch about the axis of the screw and the other way to again tighten the switch to said structure.