US3788251A

US3788251A - Multistage device for the control of the air supply for pneumatic aligning members

Info

Publication number: US3788251A
Application number: US00309964A
Authority: US
Inventors: G Haak
Original assignee: Union Special GmbH
Current assignee: Union Special GmbH
Priority date: 1971-12-04
Filing date: 1972-11-28
Publication date: 1974-01-29
Anticipated expiration: 1991-01-29
Also published as: GB1418883A; IT972387B; FR2164266A5

Abstract

This disclosure relates to a multistage control arrangement for the control of the air supply for a pneumatic aligning member for the alignment of the threads or chains of threads relative to a cutter of a sewing machine, which in the first flow controlling position blocks the air supply in the case of a stopped sewing machine, in the second flow controlling position releases the air supply approximately simultaneously with the starting of the sewing machine, and in the third flow controlling position again blocking the air supply generally at the time when the normal operating speed of the sewing machine is reached.

Description

United States Patent Haak Jan. v29, 1974 [54] MULTISTAGE DEVICE FOR THE 3,347,194 10/1967 Hale et a1 112/219 B CONTROL OF THE AIR SUPPLY O 3,407,762 10/1968 Winer 112/219 B 3,443,540 5/1969 l-lannemann et al...; 112/252 PNEUMATIC ALIGNING MEMBERS 3,541,982 11/1970 Marforio 112/219 B [75] Inventor: Giinter Haak, Stuttgart, Germany 3,667,410 6/1972 Bianchi 112/219 B X [73} Assignee: g i Maschi'enfabrik Primary ExaminerWerner l-l. Schroeder tuttgart ermany Attorney, Agent, or FirmCharles E. Brown et a1. [22] Filed: Nov. 28, 1972 [21] Appl. No.: 309,964 7 ABSTRACT ThlS disclosure relates to a multistage control arrangement for the control of the air supply for a pneumatic 1 1 Foreign Appllcatlon n y Data aligning member for the alignment of the threads or Dec. 4, 1971 Germany G 71 45 738.0 chains of threads relative to a cutter of a sewing machine, which in the first flow controlling position [52] U.S. Cl 112/252, 251/321, 251/324 blocks the air supply in the case of a stopped sewing [51] Int. Cl...; I 05b 6 5 [02 machine, in the second flow controlling position re- [5 8] Field of Search ..1 12/219 R, 219 A, 219 B, leases the air supply approximately simultaneously ll2/252.DIG. 1.DIG.3;251/321,324 with the starting of the sewing machine, and inthe third flow controlling position again blocking the air [56] References Cited supply generally at the time when the normal operat- UNITED STATES PATENTS ing speed of the sewing machine is reached. 3,298,341 1/1967 Bonis 112/219 B 12 Claims, 10 Drawing Figures L l I J F 4] PATENTH] JAN 2 91974 SHEU 2 OF 2 MULTISTAGE DEVICE FOR THE CONTROL OF THE AIR SUPPLY FOR PNEUMATIC ALIGNING MEMBERS This invention relates to a multistage control arrangement for the control of the air supply for a pneumatic aligning member for the alignment of the threads or chains of threads relative to a cutter ofa sewing machine, which in the first flow controlling position blocks the air supply in the case of a stopped sewing machine and in the second flow controlling position releases the air supply approximately simultaneously with the starting of the sewing machine.

BACKGROUND OF THE INVENTION It has been known in the construction and use of a sewing machine to align the threads or chains of threads formed thereby by means of air in relation to a thread cutting device. Various arrangements have been provided in which either a stream of compressed air is directed onto the threads or chains of thread leaving the place for formation of a stitch in order to align them relative to a cutter and in order to move them between the blades, as is disclosed, for example, in U. S. Pat. No. 3,541,984 to Daniel, or the threads or chains of thread are sucked by means of suction into the cutting arrangement as is disclosed, for example, in U. S. Pat. No. 3,143,987 to Daniel. In view of the fact that the consumption of air is relatively high in both of the above-discussed cases, arrangements have been made to bring about a temporary cutting off of the air when it is not needed.

One advantageous arrangement devised for the control of the air supply to the pneumatic aligning members includes a valve disposed in the conventional tension rod system between the usual control pedal and the coupling lever of the drive of the sewing machine. This valve blocks the air supply while the sewing machine is stopped and releases the air supply as soon as the sewing machine is put in motion. But even in the case of the prior control arrangement for the air supply, the consumption of air is still relatively high and the operation of the cutter is still relatively expensive irrespective of whether a vacuum or compressed air must be produced. This is particularly noticeable whenever the standstill time of the sewing machine relative to the sewing time is relatively short.

SUMMARY OF THE INVENTION This invention is based on the objective of improving the prior multistage arrangement for the control of the air supply to the pneumatic thread aligning members in order to further reduce air consumption. This objective is achieved by providing a third switching position for the valve to block the air supply approximately when the operating speed of the sewing machine is reached.

By providing a third switching position of the valve in the case of such a multistage arrangement for the control of the air supply, the air supply is released only at the start of sewing and at the end of the sewing process. Thus, the required air supply is reduced to a minimum. Nevertheless, a perfect functioning of the cutting arrangement is guaranteed, since under normal conditions the sewing material will have passed the cutting arrangement prior to the sewing machine reaching its operating speed and the threads or chains of thread are already cut. If the material is removed from the place for formation of the stitch, the sewing machine as a rule is stopped, and under these conditions too it will be sufficient if the air supply is switched on only during the time the control pedal is actuated for control of the sewing machine drive.

An advantageous characteristic of the control arrangement is that the closing force required to place the air supply control in the first flow controlling position is smaller than, and that the second flow controlling position of the valve requires a force which is greater than, the force which is to be overcome initially for engagement of the drive of the sewing machine, whereby the control arrangement for the valve may be disposed in a conventional manner in the tension rod system between the sewing machine pedal and motor. In a preferred embodiment of the invention a single valve with three flow controlling positions is disposed in the tension rod mechanism.

In another embodiment of the invention, two control valves arranged in series, each with two flow controlling positions, are disposed in the tension rod mechanism, a first of the valves being closed in the sewing machine starting position and is under the influence of a closing force which is smaller than the force required for engagement of the sewing machine drive, while the second of the valves is held in an opened position by a force that is larger than the force that is required to initially overcome for the purpose of engaging the sewing machine drive.

Another possible embodiment of the invention utilizes, in series with control valve having two controlling positions and closed in the starting position, a second valve having two flow controlling positions, the second valve being disposed in the tension rod mechanism below the control pedal. Moreover, it is also possible to dispose a control valve with a rotary valve element in the swiveling axis of the control pedal. Withthe above and other objects in view that will hereinafter appear, the nature of the invention will be more clearly under stood by reference to the following detailed description, the appended claims and the several views illustrated in the accompanying drawings:

IN THE DRAWINGS FIG. 1 is an elevational view of a sewing machine set up on a table;

FIGS. 2a, 2b and 2c are enlarged schematic sectional views of a control valve in various switching positions.

FIG. 3 is a fragmentary elevational view showing a modified form of control valve arrangement.

FIGS. 4 and 5 are enlarged schematic sectional views taken through the control valves of FIG. 3.

FIG. 6 is a fragmentary elevational view similar to FIG. 4 and shows still another control valve arrangement. I

FIG. 7 is an enlarged sectional schematic view of still another control valve.

FIG. 8 is a fragmentary elevational view of yet another control valve arrangement.

Referring now to the drawings, it will be seen that a conventional sewing machine 1 is mounted in the traditional manner on a table 2, which, below the top thereof, carries the usual driving motor 3 for the sewing machine 1. The driving motor 3 is connected with a control pedal 5 by way of a control rod system 4. The sewing machine 1 has a thread cutting device of a conventional type and, therefore, not shown in detail, in which the chain of threads formed by the sewing machine is aligned by means of an air pipe relative to the blades of the thread cutting device. As shown in FIG. 1, this air comes from a supply source through a conduit 6, which is connected with the thread aligning members via a conduit 7. Air flow between the

conduits

6 and 7 is through a control valve 8. Details of the control valve 8 are best shown in FIGS. 2a, 2b and 2c.

The control valve 8 has an inlet 9 and an outlet 11 which are coupled to the

conduits

6 and 7, respectively. The valve 8 is in the form of a cylinder and has a valve member 10 therein with two blocking elements l2, 13. The body of the valve 8 is connected to one part of a rod 4a and the valve member 10 is connected to another part of a like or same rod, the rod 4a being a part of the control rod system 4. Between the

blocking elements

12, 13 there is a passage 14. The valve 8 also includes two

concentric springs

15, 16 which are operable to urge the valve member 10 towards a normal first position when the sewing machine 1 is inoperative. The valve member 10 is forced by the

springs

15, 16 towards the position shown in FIG. 2a with the spring 15 holding the valve member 10 in the illustrated position. Spring 15 is weaker than the force counteracting the engagement of the sewing machine drive by pressing down on pedal 5. Spring 16 is stronger than the force which is to be overcome initially to put the sewing machine 1 into operation.

In the starting position corresponding to FIGS. 2a flow between

conduits

6 and 7 is blocked by valve 8. This corresponds to the starting position of control pedal with sewing machine 1 being at standstill. When pedal 5 is depressed, the valve member 10, counter to the force of spring 15, is drawn into the position according to FIG. 217 before operation of the sewing machine starts. The valve member is held in this position by the added resistance of spring 16 during the further depression of pedal 5. Therefore, the sewing machine 1 starts running and the flow passage through the valve 8 is open. Only through a further depression of pedal 5 overcoming the greater resistance developed by the springs and 16 will valve member 10 travel to the position of FIG. 20. Now the upper part 12 of the valve member blocks flow through the valve 8. Accordingly, during the normal operation of the sewing machine I, when the operating speed of the sewing machine is reached, the passage between

conduits

6, 7 is blocked by the valve 8.

When the pedal 5 is swung back towards its normal position, the control of the air supply is accomplished in the reverse manner. Whenever pedal 5 approximately reaches the position in which the drive of the sewing machine is switched off, the valve member 10 stands in the position according to FIG. 2b. The passage between the

conduits

6, 7 is opened again and alignment of the chain of threads, relative to the cutter, takes place during the deceleration of the sewing machine 1. The seamstress holds the pedal 5 in this position until the machine has decelerated and the chain of threads is cut, whereupon she takes the pressure off altogether. As a result of the complete release of pedal 5, the valve member returns to the position according to FIG. 2a and the passage between the

conduits

6, 7 is again blocked.

Referring now to FIG. 3 is particular, it will be seen that there is illustrated a modified form of control valve arrangement incorporated in the control rod system 4. Instead of providing a single three position valve, such Referring now to FIG. 4, it will be seen that the valve I 20 includes a housing 22 with an inlet 23 and an outlet 24. The housing is provided at the upper end thereof with a rod portion 25 which forms part of the control rod system 4 and has mounted therein for reciprocatory movement a valve element 26. The valve element 26, which has a rod portion 27 forming part of the control rod system 4 connected thereto, is urged towards an uppermost position by a light spring 28.

The spring 28 normally holds the valve element 26 in a position blocking flow between the inlet 23 and the outlet 24. However, when the pedal 5 is actuated to start the sewing machine 1, the pressure of the spring 28 will be overcome before the sewing machine 1 is actuated with the result that the valve element 26 will move from its flow blocking position to a position seated on the valve body 22 below the line of communication between the inlet 23 and outlet 24.

Referring now to FIG. 5, it will be seen that there are illustrated the details of the valve 21. The valve 21 includes a valve body 30 which is provided with an inlet 31 and an outlet 32. The valve body 30 has connected to the upper end thereof a rod portion 33 which forms a part of the control rod system 4.

Disposed within the upper part of the valve body 30 and normally permitting freedom of communication between the inlet 31 and the outlet 32 is a valve element 34. The valve element 34 is held in this uppermost position by means of a relatively heavy spring 35.

The valve element 34 has connected thereto the upper end of the rod portion 25 or a similar rod portion. When the control pedal 5 is initially depressed to start the sewing machine I, while the spring 28 may be overcome, the spring 35 permits the transfer of the necessary actuating force through the valve 21 to the control for the drive motor 3. However, when the control pedal 5 is further moved, the spring 35 will be compressed and the valve element 34 will move to a position blocking the passage between the inlet 31 and the outlet 32.

It is to be noted that the conduit 6 is connected to the valve 20 while the conduit 7 is connected to the outlet of the valve 21. The outlet of the valve 20 is coupled to the inlet of the valve 21 by means of a conduit 36.

It is to be understood that the operation of the control for air flow passing between the

conduits

6 and 7 will be the same as that described with respect to the embodiment of FIG. 1 except that instead of a single valve being utilized, the two

valves

20, 21 coupled in series are utilized.

Referring to FIG. 6, it will be seen that there is illustrated a slightly different series valve arrangement. A valve, generally identified by the numeral 36 and corresponding to the valve 21 is mounted beneath the control pedal 5 and is suitably coupled thereto. The valve 36, as is best illustrated in FIG. 7, includes a valve body 37 having an inlet 38 and an outlet 40. Mounted within the body 37 for limited movement is a valve element 41 which has connected thereto a rod element 42 which may or may not form part of the control rod system 4. It is to be noted that the initial position of the valve element 41 is well above the inlet 38 and outlet so that flow through the valve 36 normally occurs. Disposed within the valve body 37 and normally spaced below the valve element 41 is a relatively heavy spring 43 which corresponds to the spring 35. When the control pedal 5 is initially moved to initiate the operation of the sewing machine, the valve element 41 will move downwardly and come into engagement with the spring 43. It will not, however, block the flow between the inlet 38 and the outlet 40 at this time. However, further normal movement of the control pedal 5 will overcome the resistance of the spring 43 so that the valve element 41 will then move down to the position blocking the flow between the inlet 38 and the outlet 40. Thus, the valve 36 will function in the same manner as that described above with respect to the valve 21.

Referring once again to FIG. 6, it will be seen that the conduit 6 is connected to the valve 20 at the inlet thereof, and that a conduit 44 extends between the outlet of the valve 20 and the inlet of the valve 36. Further, the conduit 7 is connected to the outlet of the valve 36 so that the

valves

20 and 36 are serially coupled.

Reference is now made to the embodiment of the invention shown in FIG. 8, and it is to be understood that the control pedal 5 is pivotally mounted in any conventional manner. For illustration purposes, the control pedal 5 has been illustrated as being mounted on a rock shaft 45. An extension of the rock shaft 45 is coupled to a rotary valve, generally identified by the numeral 46. The rotary valve 46 is of a conventional type, and accordingly, the internal details thereof are not specifically illustrated. It is to be understood that the internal configuration of the valve 46 is such that in the at rest position of the control pedal 5, the valve is open to flow therethrough. Further, when the pedal 5 is depressed to initiate the operation of the sewing machine, the valve 46 will still be open for flow therethrough. At this time, suitable spring means having a force corresponding to the

springs

16, 35 and 43, will resist further rotation of the valve element of the valve 46. When the control pedal 5 is further depressed, the valve element of the control valve 46 will rotate to a position blocking flow therethrough.

It is to be also noted that in the embodiment of FIG. 8 the control valve 20 is mounted in the control rod system 4. Further, the conduit 6 is connected to the inlet of the valve 20 and a conduit 47 extends from the outlet of the valve 20 to an inlet of the valve 46. The outlet of the valve 46 has connected thereto the conduit 7. It thus will be readily apparent that the

valves

20 and 46 are series coupled and that the sequence of actuation thereof is the same as that described with respect to the

valves

20 and 21 in FIG. 3.

At this time it is further pointed out that the control valve 36 may be of the three position type and used independently of a further valve, such as the valve 20. The initial position of valve 36 would be closed, the second position would be open, and the third position would be closed.

Although only a preferred embodiment of the invention has been specifically illustrated and described herein, it is to be understood that minor variations may be made in the air control system for the thread aligning device without departing from the spirit and scope of the invention, as defined in the appended claims.

I claim:

1. A multistage control arrangement for the control of the air supply to a pneumatic aligning member for the alignment of threads or chain of threads produced by a sewing machine relative to a thread cutter of a sewing machine, said control arrangement having a first controlling position for blocking the air supply while the sewing machine is at standstill and a second flow controlling position for releasing the air supply generally at the time of starting of the sewing machine; the improvement residing in a third flow controlling position for blocking the air supply generally at the time when the normal operating speed of the sewing machine is achieved.

2. A control arrangement according to claim 1, wherein the control arrangement is particularly constructed for operative association with an actuator of a drive for an associated sewing machine requiring a predetermined actuating force, the control valve arrangement in the first flow controlling position thereof having a closing force exerted thereon which is smaller than the predetermined actuating force and in the second flow controlling position thereof having a force exerted thereon which is larger than the predetermined actuating force.

3. A control arrangement according to claim 2 wherein said control arrangement is in the form of a single valve with three flow controlling positions, and said valve has means thereon for incorporating the same as part of an actuator for the drive of an associated sewing machine.

4. A control arrangement according to claim 2 wherein there are two control valves, each with two flow controlling positions and coupled in series, the first of said control valves being closed in the starting position and being under the influence of a closing force that is smaller than the force required for engagement of the drive, and the second control valve being initially held in an opened position by a force that is larger than the force to be overcome initially for engagement of the drive.

5. A control arrangement according to claim 4 wherein said second valve is particularly adapted to be disposed below the control pedal associated therewith.

6. A control arrangement according to claim 4 wherein said second control valve is a rotary valve particularly adapted to be mounted on a pivot axis of a pivotally mounted control pedal for actuation thereby.

7. A control arrangement according to claim 1 wherein said control arrangement is in the form of a single valve with three flow controlling positions, and said valve has means thereon for incorporating the same as part of an actuator for the drive of an associated sewing machine.

8. A control arrangement according to claim 1 wherein there are two control valves, each with two flow controlling positions and coupled in series, the first of said control valves being closed in the starting position and being under the influence of a closing force that is smaller than the force required for engagement of the drive, and the second control valve being initially held in an opened position by a force that is larger than the force to be overcome initially for engagement of the drive.

9. A control arrangement according to claim 8 wherein said second valve is particularly adapted to be disposed below the control pedal associated therewith.

10. A control arrangement according to claim 8 wherein said second control valve is a rotary valve particularly adapted to be mounted on a pivot axis of a pivotally mounted control pedal for actuation thereby.

11. A control arrangement according to claim 1 wherein said control arrangement includes a rotary valve particularly adapted to be mounted on a pivot axis of a pivotally mounted control pedal for actuation thereby.

12. A multistage control arrangement for the control of the air supply to a pneumatic aligning member for the alignment of threads or chain of threads produced by a sewing machine relative to a thread cutter of a sewing machine, said control arrangement having a first controlling position for blocking the air supply while the sewing machine is at standstill and a second flow controlling position for releasing the air supply larger than the predetermined actuating force.

Claims

12. A multistage control arrangement for the control of the air supply to a pneumatic aligning member for the alignment of threads or chain of threads produced by a sewing machine relative to a thread cutter of a sewing machine, said control arrangement having a first controlling position for blocking the air supply while the sewing machine is at standstill and a second flow controlling position for releasing the air supply generally at the time of starting of the sewing machine; the improvement residing in a third flow controlling position for blocking the air supply, said control arrangement being particularly constructed for operative association with an actuator of a drive for an associated sewing machine requiring a predetermined actuating force, the control valve arrangement in the first flow controlling position thereof having a closing force exerted thereon which is smaller than the predetermined actuating force and in the second flow controlling position thereof having a force exerted thereon which is larger than the predetermined actuating force.