US3008747A

US3008747A - Vacuum-type material handling system

Info

Publication number: US3008747A
Application number: US31594A
Authority: US
Inventors: George F Lytle
Original assignee: Whiting Corp
Current assignee: Whiting Corp
Priority date: 1960-05-25
Filing date: 1960-05-25
Publication date: 1961-11-14
Anticipated expiration: 1978-11-14

Description

G. F. LYTLE VACUUM-TYPE MATERIAL HANDLING SYSTEM Nov. 14, 1961 2 Sheets-Sheet 2 Filed May 25, 1960 a y 15 albfl l United States Patent 3,008,747 VACUUM-TYPE MATERIAL HANDLING SYSTEM George F. Lytle, Olympia Fields, Ill., assignor to Whiting Corporation, a corporation of Illinois Filed May 25, 1960, Ser. No. 31,594 8 Claims. (Cl. 294-64) The present invention relates to an improved vacuumaction material handling system of the type adapted for handling non-porous material of either flat or irregular shapes, such as plates, tubing, etc.

I Material handling systems of this type generally include one or more vacuum or lifting cups, pads, or grippers for contact with the material to be handled. Such :cups are normally connected to the suction port of a vacuum pump, there being valve means for connecting ,the vacuum cups to atmosphere or to the exhaust of the pump, thereby releasing the material being handled. In-

asmuch as any shut-down of the pump, such as would l be caused'by a power failure to an electric motor driving .the pump, would result in a loss of the lifting vacuum developed at the vacuum cups, material handling systems of this type normally include, as a safety feature, an auxiliary vacuum source and means operable automatically upon the occurrence of such a power failure to connect the vacuum cups to the auxiliary vacuum source.

It is highly desirable that the switch-over of the vacuum cups from the vacuum side of the pump to the auxiliary vacuum source be accomplished in a manner such that there will be little or no drop in the lifting vacuum at the lifting cups.

It is therefore the general object of the invention to provide a new and improved vacuum-type material handling system of the character described wherein the vacuum line to the vacuum cups is automatically switched instantaneously, upon failure of the pump, from the vacuum port of the pump to an auxiliary vacuum source without any appreciable drop in the vacuum pressure at the vacuum cups.

A more specific object of the invention is to provide a new and improved vacuum-type material handling sys- .tem of the character described wherein an electrically controlled valve is provided for positively and instantaneously switching the vacuum line to the vacuum cups' from communication with the vacuum port of the pump to communication with a reserve vacuum or safety tank upon a shut-down of the pump, as would occur in the 7 event of a power failure to an electric motor driving the pump.

Certain other objects of the invention will, in part, be

L obvious and will, in part, appear hereinafter.

For a more complete understanding of the nature and scope of the invention reference may now be had to the accompanying drawings wherein:

FIG. 1 is a perspective view, from the top and front,

10f the material gripping portion of a vacuum-type material handling unit embodying the invention;

FIG. 2 is a diagrammatic view of the vacuum system of the material handling unit illustrating the operating condition of the system wherein a seal has been established between the lifting cups and an object to be isolated from the vacuum pump and placed in communication with the reserve vacuum tank; and

70 FIG. 5 is a diagrammatic view of the electrical control circuit for the system.

3,008,747 Patented Nov. 14, 1961 "ice In the embodiment of the invention illustrated in FIG. 1, the vacuum-type material handling unit includes a plurality of lifting devices such as vacuum or suction cups 10 supported from the underside of a beam 11 which beam is in turn supported in a suitable manner from the hook 12 of an overhead hoist or crane 13. The vacuum cups 10 are illustrated as being in sealed lifting engagement with a plate 14 which could be a sheet of steel, for example. Although the vacuum cups 10 illustrated in the drawings comprise no part of the invention and thus are not shown and described in detail, it is noted that they are of the general type which includes a sealing ring formed of soft rubber and having a feathered contact edge whereby the article to be lifted is engaged with a quick seal.

The illustrated vacuum system includes, as best shown in FIGS. 2, 3 and 4, a vacuum pump 15 having a suction or vacuum port 16 and an exhaust port 17, which pump is adapted to be driven by a conventional electric rotary motion motor 18, (FIG. 5), and a reserve vacuum or safety tank 19 providing an auxiliary vacuum source. Other suitable power means may, of course, be provided for driving the pump 15. A three-way valve 21, which is controlled by a solenoid 22, has one port 23 connected to the vacuum port 16 of the pump 15 by a line 24, a second port 25 connected to the reserve vacuum tank 19 by a line 26 and a third port 27 connected to one end of the main vacuum or suction line 28. The opposite end of the main vacuum line,28 is connected to one port 29 of a four-way valve 30 which is controlled by a solenoid 31. A second port 32 of the valve 30 is connected to a line 33 which leads to the vacuum cup 10 with a third port 34 being connected to the exhaust port 17 of the pump 15 by a line 35 and a fourth port 36 being connected to atmosphere through a line 37 which includes a muffler 38. The line or hose 33 leading to the vacuum cup 10 includes a filter 39, a vacuum gauge 40, and a pressure switch 41 which serves to actuate a signal light 42 only when the vacuum cup 10 is sealed in lifting engagement with an object to be lifted, as illustrated by the condition of the system in FIG. 2. A reserve vacuum line 43 is connected between the safety or reserve vacuum tank 19 and the line 33 leading to the vacuum cup device 10. The reserve vacuum line 43, which is provided with a vacuum gauge 44-,

includes a check valve 45 which is arranged to allow the passage of air from the tank 19 to the line 33 only.

The electrical control circuit for the illustrated embodiment of the vacuum-type material handling system is shown in FIG. 5. The electric motor 18 is connected to power lines and 51 of a 220 volt A.C. source 49, for example, by a pair of

conductors

52 and 53 through terminals A and B of a terminal box 54. A normally open start button 55 is series connected in the conductor 52 and a normally closed stop button 56 is series connected in the conductor 53 for controlling the operation of the pump motor 18. A pair of

conductors

57 and 58 are connected, respectively, between the conductor 52 and terminal G and between the conductor 53 and terminal H, with the conductor 57 including a fuse 59.. The

conductors

57 and 58 are connected to the

conductors

52 and 53 between the motor 18 and the start and

stop buttons

55 and 56 whereby they are continuously energized during operation of the motor 18. The terminals G and H of the terminal box 54 may therefore be described as power terminals.

One terminal of the solenoid 22 of the three-way valve 21 is connected to the power terminal G by

conductors

60 and 61 and the other terminal of the solenoid '22 is connected to the power terminal H by a conductor 62 whereby the solenoid 22 is continuously energized during operation of the motor 18. One terminal of the solenoid 31 of the four-way valve 30 is connected to the power vided therebetween.

terminal G by

conductors

63 and 61. The other termi nal of the solenoid 31, however, is connected to the power terminal H through a conductor 64, terminals F, a conductor '65, a normally open switch 66, and a conductor 67. It is thus evident that the solenoid 31 of the four-way valve 3t] is energized only when the motor 13 is running and the switch 66 is closed manually.

One terminal of the signal light 42 is connected to the r power terminal H by a conductor 68. The other terminal of the signal light 42 is connected to the power terminal G through a conductor 69, terminals E, a conductor '70, the pressure switch 41, and a conductor 71. The pressure switch 41 is adapted to close only when a predetermined amount of vacuum has been induced in the line 33 which leads to the vacuum cup 11}, which amount of vacuum is sufficient to permit lifting or handling of the object against which the vacuum cup is sealed. This vacuum condition exists immediately upon the establishment of the seal between the vacuum cup 10 and the object to be handled. Therefore, the signal light 42 will be energized or lit only when the motor 18 is operating and a sufficient vacuum is present in the line 33 which leads to the vacuum cup 10, as illustrated in FIG. 2.

The operation of the vacuum-type material handling system disclosed herein will now be described, The

pump motor 18 is first energized by pressing the start button 55 As previously described herein, power will then be directed to the power terminals G and H of the terminal box 54 with the solenoid 22 of the three way valve 21 being energized and the solenoid 3d of the fourway valve '30 being de-energized. The structure of the valve 21 is such that when .the solenoid 22 is energized, an internal passage 75 is provided between the

ports

23 and 27 whereby to connect the vacuum port 16 of the pump with the main vacuum line 28. The structure of the valve 30 is such that when the solenoid 31 is deenergized, an internal passage 76 is provided between the ports 29 and 32 and a passage 77 is provided between the ports 34 and 36. The vacuum cup 10 is therefore connected directly to the vacuum port 16 of the pump 15 by the line 33, the passage 76 in the valve 30, the main vacuum line 28, the passage 75 in the valve 21 and the line 24 with the exhaust port 17 of the pump 15 being connected to atmosphere by the line 35, the passage 77 in the valve 30, and the line 37. Thus, as soon as the pump -motor 18 has been actuated, a suction or vacuum is provided at the lifting cup 10. The lifting cup '10 may then be brought into contact with the surface of the object to be lifted whereupon a seal is immediately pro- As soon as the seal is established and the vacuum in the line 33 is sufficient to actuate the signal light 42 as previously described herein, the check valve 45 in the reserve vacuum line 43 will open automatically whereby communication is established between the vacuum port 16 of the pump 15 and the reserve vacuum tank I19 (via the line 24, the passage 75 in the valve 21, the line 28, the passage 76 in the valve 30, the

check valve 45, and the line 43) to create the desired degree of vacuum in the tank 19. This operating condition of the system is illustrated in FIG. 2 of the drawings. The valve 45 opens automatically only when there is a sutficient difference in pressure on opposite sides thereof to overcome the light spring tension that normally holds the check valve 45 closed. When the maximum vacuum has been achieved in both the tank 19 and the connecting line 33, the pressure on opposite sides of the valve 45 will be equalized and the valve 45 will close to retain the maximum vacuum in the tank 19.

When it is desired to release the object supported from the lifting cup 10, the push button switch 66 is manually closed whereupon the solenoid 3 1 of the four-way valve 30 is energized, as previously described herein. When the solenoid 31 is energized, the

passages

76 and 77 are closed on and a passage 78 is provided between the "ports 29 and 36 of the valve 30 and passage 79 is provided between the poits 34 and 32 of the valve 30. In this condition of the system, as is illustrated in FIG. 3 of the drawings, the vacuum port 16 of the pump 15 is connected to atmosphere (via the line 24-, the passage in the valve 21, the line 28,-the passage 78 in the valve 30, and the line 37) and the exhaust port 17 of the pump 15 is connected to the lifting cup 10' (via the line 35, the passage 79 in the valve 30, and the line 33) whereby the full exhaust displacement of the pump 15 is positively applied to the area of the lifting cup 10 to effectively and positively separate the cup 10 from the material being handled. In this condition of the system, the check valve 45 is closed whereby to preserve the desired degree of reserve vacuum in the tank '19.

In the event of a power failure during a lifting operation, as illustrated by the normal operating condition of the system in FIG. 2, there will be no power to the pump motor18 or to the power terminals G and H. Simultaneously with the cut-off of power to the terminals G and H, the solenoid 22 of the three-way valve 21 will be deener'gized. When the solenoid 22 is de-energized, the passage 75 between the

ports

23 and 27 of the valve '21 is instantaneously closed off and a passage 80 (FIG. 4) is simultaneously provided between the

ports

25 and 27 of the valve 21. Provision is thus made for positively and instantaneously disconnecting the vacuum cup 10 from the vacuum port 16 of the pump 15 and simultaneously connecting the vacuum cup 10 to the reserve vacuum tank 19 through the line 33, the passage 76 in the valve 30, the line 28, the passage 80 in the valve 21, and the line 26. This positive action of the valve 21 is so instantaneous that there is no appreciable decrease in the vacuum at the vacuum cup 10 during the switch over from the pump 15 to the safety tank 19 thus eliminating any possibility of the object supported from the vacuum cup 10 being released upon the oocurrence of a power failure. This condition of the system is illustrated in FIG. '4. The vacuum in the reserve vacuum tank 19 is sufiicient to maintain the necessary lifting vacuum at the vacuum cup 10 for a long enough period either to permit the supported object to be lowered to a supporting surface by means of the overhead hoist 13 or to permit an auxiliary power supply to be connected to the pump motor 18.

In installation wherein non-electrical driving means are provided for the pump 15, suitable auxiliary electrical power means may be provided for the various valve solenaids and signal lamps.

It will be understood that certain changes may be made in the construction or arrangement of the vacuum-type material handling system disclosed herein without departing from the spirit and scope of the invention as defined in the appended claims.

I claim:

1. In a vacuum-type material handling system having a vacuum pump including a vacuum port and an exhaust port, a main vacuum line and an exhaust line associated with the pump, a vacuum cup in communication with the main vacuum line with the vacuum serving-to hold the material to the cup upon the cup engaging the surface of the material, and a reserve vacuum tank, the improvement which comprises, a solenoid actuated three-way valve connected between the vacuum port of said pump and said reserve vacuum tank, which valve selectively serves to positively connect said main vacuum line to the vacuum port of said pump when said solenoid is energized and the pump is operating and to positively connect said main vacuum line to said reserve vacuum tank when said solenoid is de-energized and the pump is not operating, a reserve vacuum line connected between said reserve vacuum tank and said main vacuum line, and a check 1 valve in said reserve vacuum line operable to permit'a vacuum to be induced in said tank by said pump when said main vacuum line is connected to the vacuum port of said pump.

1 2. In a vacuum-type material handling system having a vacuum pump including a vacuum port and an exhaust port, a main vacuum line and an exhaust line associated with the pump, a vacuum cup in communication with the main vacuum line with the vacuum serving to hold the material to the cup upon the cup engaging the surface of the material, and a reserve vacuum tank, the improvement which comprises, a solenoid controlled three-way valve connected between the vacuum port of said pump and said reserve vacuum tank, circuit means energizing said solenoid during operation of said pump, said valve serving to connect said main vacuum line to the vacuum port of said pump when said solenoid is energized and serving to instantaneously break said connection and connect'said main vacuum line to said reserve vacuum tank when said solenoid is de-energized, a reserve vacuum line connected between said reserve vacuum tank. and said main vacuum line, and a check valve in said reserve vacuum line.

3. In a vacuum-type material handling system having a vacuum pump including a vacuum port and an exhaust port, means for driving said pump, a main vacuum line and an exhaust line associated respectively with the vacuum and exhaust ports of the pump, a vacuum cup in communication with the end of the main vacuum line with the vacuum serving to hold the material to the cup upon the cup engaging the surface of the material, and a reserve vacuum tank, the improvement which comprises, a pair of conductors connected to a source of electrical power, which conductors are adapted to be energized only during operation of the pump driving means, a reserve vacuum line connecting said tank to said main vacuum line, a solenoid controlled three-way valve for selectively connecting said main vacuum line to the vacuum port of said pump and to said reserve vacuum tank, said three-way valve being operable to connect said main vacuum line to the vacuum port of said pump when the solenoid thereof is energized and being operable to connect said main vacuum line to said tank when the solenoid thereof is de-energized, circuit means connecting the solenoid of said three-way valve to said pair of conductors whereby said solenoid is continuously energized during the operation of said pump driving means to connect said main vacuum line to the vacuum port of the pump and whereby said solenoid is de-energized upon a shut-down of said pump driving means to instantaneously and positively disconnect said main vacuum line from said pump and connect said main vacuum line to said reserve vacuum tank, and a check valve in said reserve vacuum line adapted to permit a vacuum to be induced in said reserve vacuum tank by said pump when said main vacuum line is connected to the vacuum port of said pump and a lifting degree of vacuum has been achieved in said main vacuum line.

4. In a vacuum-type material handling system having a vacuum pump including a vacuum port and an exhaust port, a main vacuum line and an exhaust line associated with the pump, a vacuum cup in communication with the end of the main vacuum line with the vacuum serving to hold the material to the cup upon the cup engaging the surface of the material, and a reserve vacuum tank, the improvement which comprises a three-way valve connected between the vacuum port of said pump and said reserve vacuum tank for selectively and positively connecting said main vacuum line to the vacuum port of said pump and to said reserve vacuum tank, a four-way valve connected between said main vacuum line and said exhaust line for selectively reversing the association thereof to said pump, a reserve vacuum line connected between said reserve vacuum tank and said main vacuum line, and a check valve in said reserve vacuum line.

5. In a vacuum-type material handling system having a vacuum pump including a vacuum port and an exhaust port, means for driving the pump, a main vacuum line and an exhaust line associated with the pump,

6 a vacuum lifting cup in communication with the end of the main vacuum line with the vacuum serving to hold the material to the cup upon the cup engaging the surface of the material, and a reserve vacuum tank, the improvement which comprises, a three- Way valve connected between the vacuum port of said pump and said reserve vacuum tank, which valve during operation of the pump normally establishes communication between the vacuum port of the pump and said main vacuum line, means automatically operable upon a shutdown of the pump driving means to actuate said three way valve whereby to disconnect said main vacuum line from said pump and simultaneously connect it to said reserve vacuum tank, a four-Way valve connected between said main vacuum line and said exhaust line for selectively reversing the association thereof to said pump, a reserve vacuum line connected between said reserve vacuum tank and said main vacuum line, and a check valve in said reserve vacuum line adapted to permit a vacuum to be induced in said reserve vacuum tank by said pump when said main vacuum line is connected to the vacuum port of said pump and a lifting degree of vacuum has been achieved therein. l

6. In a vacuum-type material handling system having a vacuum pump including a vacuum port and an exhaust port, a main vacuum line and an exhaust line associated with the pump, a vacuum cup in communication with the end of the main vacuum line with the vacuum serving to hold the materialto the cup upon the cup engaging the surface of the material, and a reserve vacuum tank, the improvement which comprises, a solenoid controlled three-way valve connected between the vacuum port of said pump and said reserve vacuum tank for selectively and positively connecting said main vacuum line to the vacuum port of said pump and to said reserve vacuum tank, a four-way valve connected between said main vacuum line and said exhaust line normally establishing communication between said main vacuum line and the vacuum port of the pump and between said exhaust line and the exhaust port of the pump, said valve being controlled by a normally de-energized solenoid, which solenoid when energized is effective to actuate said valve whereby to reverse the association of said main vacuum and exhaust lines to said pump, circuit means for energizing the solenoid of said four-way valve, a reserve vacuum line connected between said reserve vacuum tank and said main vacuum line, and a check valve in said reserve vacuum line.

7. In a vacuum-type material handling system having a vacuum pump including a vacuum port and an exhaust port, a main vacuum line and an exhaust line associated with the pump, a vacuum cup in communication with the end of the main vacuum line with the vacuum serving to hold the material to the cup upon the cup engaging the surface of the material, and a reserve vacuum tank, the improvement which comprises, a solenoid controlled three-way valve connected between the vacuum port of said pump and said reserve vacuum tank, circuit means energizing said solenoid during operation of said pump, said valve serving to connect said main vacuum line to the vacuum port of said pump when said solenoid is energized and serving to instantaneously break said connection and connect said main vacuum line to said reserve vacuum tank when said solenoid is de-energized, a solenoid controlled four-way valve connected between said main vacuum line and said exhaust line for selectively reversing the association thereof to said pump, a reserve vacuum line connected between said reserve vacuum tank and said main vacuum line, and a check valve in said reserve vacuum line.

8. In a vacuum-type material handling system having a vacuum pump including a vacuum port and an exhaust port, an electric motor connected to drive the pump, first circuit means for connecting the motor to a source of electrical power, a main vacuum line and an exhaust the vacuum serving to hold the material to the cup upon the cup engaging the surface of the material, the im- Qprovement which comprises, a pair of conductors connected tosaid first circuit means, which conductors are energized only during operation of said motor, a solenoid controlled four-way valve adapted when the solenoid thereof is energized to reverse the association of the main vacuum line and the exhaust line relative to the pump, second circuit means including a normally open switch connecting the solenoid of said four-way valve to said vpair o'f conductors whereby said solenoid is energized only when said switch is closed during operation of said motor, a reserve vacuum tank, a reserve vacuum line connecting said tank to said main vacuum line, a solenoid controlled three-way valve for selectively connecting said main vacuum line to the vacuum port of said pump and to said reserve vacuum tank, said three-way valve being operable to connect said main vacuum line to the vacuum port of said pump when the solenoid thereof is energized and being operable to connect said main vacuum line to said tank when the solenoid thereof is 'de-energized, third circuit means connecting the solenoid of said three-way valve to said pair of conductors whereby said solenoid is continuously energized during operation of said motor to connect said main vacuum line to the vacuum port of the pump and whereby said solenoid is tie-energized upon a power failure to said motor to instantaneously disconnect said main vacuum line from said pump and connect said main vacuum line to said reserve vacuum tank, and a check valve in said reserve vacuum line adapted to permit a vacuum to be induced in said reserve tank by said pump when said main vacuum line is connected to the vacuum port of said pump and a lifting degree of vacuum has been achieved therein.

References Cited in the file 'of this patent UNITED STATES PATENTS nal-