US3657966A

US3657966A - Multi-position vacuum motor

Info

Publication number: US3657966A
Application number: US42195A
Authority: US
Inventors: Lawrence Frank Campbell
Original assignee: Scovill Inc
Current assignee: ROSTRA ENGINEERED COMPONENTS Inc A CORP OF CT; Scovill Inc
Priority date: 1970-06-01
Filing date: 1970-06-01
Publication date: 1972-04-25
Anticipated expiration: 1989-04-25

Abstract

A multi-position vacuum motor has extending from its diaphragm an actuating element of selected length which holds open a check valve to vent the chamber and permits the diaphragm to move from the extreme position to intermediate position in a dependable way irrespective of the amount of time a remote vent valve is held open.

Description

United States Patent Campbell [4 1 Apr. 25, 1972 [54] MULTI-POSITION VACUUM MOTOR [56] References Cited [72] inventor: Lawrence Frank Campbell, Springfield, UNITED STATES PATENTS Ohio 2,782,025 2/1957 [73] Assignee: Scovill Manufacturing Company, Water- 2,990 349 7 19 1 bury, Conn. 3,072,108 1/ 1963 [22] Filed: June 1,1970 3,334,545 8/1967 3,381,582 5/1968 1 PP 42,195 3,405,607 10/1968 Application Data Primary ExaminerPaul E. Maslousky [63] Continuation-impart of Ser. No. 784,761, Dec. 18, Attorney-Daliett l-loopes 1968, abandoned.

[57] ABSTRACT [52] U.S.Cl ..91/357,91/395,92/99,

92/110 A multl-posltlon vacuum motor has extending from its 51 Int. Cl ..Fl5b 9/02,F16j3/00 diaphragm actuating element Salem! length which 53 FieldofSeareh ..91/394, 395,396, 409, 357-, holdsopenacheck valveto vemthe chamberand Permitslhe diaphragm to move from the extreme position to intermediate position in a dependable way irrespective of the amount of time a remote vent valve is held open.

11 Claims, 9 Drawing Figures PATENTEDAPR 25 I972 3. 657, 966

SHEET 1 BF 2 Fig.2 Fig.3

1 INVENTOR. Lawrence F; Campbell ATTORNEY.

PATENTEBAPR 25 I972 SHEET 2 BF 2 lllll I'NVENTOR Lawrence F. Campbell ATTORNEY L my BY W MUUIT-POSITION VACUUM MOTOR carburetor intake. and operate the automobiledefroster and.

heating systemsastdesired. Among'the prior art showings are U.S. Pat. Nos. 3,125,001, 3,072,108, and3,380,349.

Attemptsof the priorart have been found lacking in that movement-from the extreme position to the intermediate position has *not been a controlled reliable movement. Venting of the motor has been doneby a remote valve on the dashboard and such ventinghas been in no way concerned with the amount of venting actually necessary to get-the motor back exactly to the intermediate position. Since the degree of vacuum inthe motor will vary, the amount of venting necessary will also vary. Hence, in prior devices there has been some undertravel or overshooting of the diaphragm short of or past the intermediate position. It is, of course, important that the motor move to the intermediate position with sureness and certainty. lf,.for instance, the venting from the extreme position is notsufficient, theoperatorwill think he has changed the climate control when actually he has not.

Under the present invention, the structure of the vacuum motor includes precise reliable internal control of the venting as the diaphragm is moved from extreme to intermediate position.

Other objects of the invention will be apparent from an examination of the following specification including the drawings wherein non-limiting examples are disclosed:

FIG. I" is a somewhatschematic view of a vacuum motor embodyingthe invention and a control system therefor, all for actuating. the heater control of an automobile vehicle. InFIG. 1', the motor andthe control valve are shown in cross section;

FIG. Zisasectional view taken on the line 2--2 of FIG. 1;

FIG. 3 is a sectional view taken on the line 3-3 of FIG. 1;

FIG. 4 is an elevational view partly; in section, slightly reduced, of avmotor embodying the invention shown in intermediate position;

FIG; 5" is an elevational view partly in section, slightly reduced, offa motor embodying the invention in extreme actuating position;

FIG. .6 is a sectional view taken on the line 66 of FIG. 5;

FIG. 7. is-a-sectional. view comparable to FIG. 6 with a different form of actuating element;

FIG. 8.:is a sectional view of a modified form of motor embodying the invention showingthe motor between extreme and intermediate positions; and

FIG. 9 isa sectional view as FIG. 8- but showing the modified formin intermediate position.

Referring more specifically to FIG. I, a motor embodying the'invention is generally designated 10. It is connected by appropriate tubingtoa rotary valve 12' which in turn isconnected to a vacuum source V.

Themotor comprises a housing 14 defined by side walls 16 and a connected end wall 18. The ward the housing has a partial. rear wall 20toprovide stop means for the motor. A movable element. comprising a. roll-type diaphragm 22 is sealingly connected to the side wall 16by a flexible web 24 in a conventionalmanner. Spring 26 biases the diaphragm 22 away from the end wall 18 tothe position shown in FIG. 1. The spring is held inposition by an inclined annular shoulder 28inthe endwall l8.

Centrally disposedin the end wall isan opening 30 to which is connecteda vacuum. source port 32. In the opening 30 is disposed a rubber check valve 34 which is biased closed but which opens upon application of a vacuum to port 32. Preferably, the check valve 34 is of the type known in the trade as duck-bill valve element which is commercially available from Vernay Laboratories, Yellow Springs, Ohio, and which comprises an integrally molded element of rubber or the like having resilient lips 34a and anannular holding flange 34b which engages about the opening30. A more elaborate form of a duck-bill valve is shown in US. Pat. No. 3,159,176.

A second vacuum source port 36 is disposed in the side wall l6 at a distance spaced from the end. wall 18. The port comprises the tube section which covers the port opening in the side wall.

Mounted centrally of the diaphragm 22 is the actuating element or stud 38. In the embodiment shown, the stud is in the fonn of a headed element which extends through the actuating arm 40 of the, motor, is secured in acentral opening in the diaphragm, and extends toward the duck-bill valve 34 and is aligned therewith. The stud 38 is shown in tubular form and has adjacent the diaphragm a radial opening 42.

In operation, as shown in FIGS. 1, 4 and 5, the diaphragm of the embodiment shown may be made to assume any one of three positions. In FIG. 1, the diaphragm is shown in its rightward position where vacuum is not connected to either of the

ports

32 or 36. In FIG. 4, vacuum is applied to port 36 only, the roll-type diaphragm moving leftward against the force of spring 26 to a position where it substantially occludes the port opening. This limits the travel of the diaphragm because if the diaphragm moves farther leftward port 36 is completely blocked. There may be small oscillation of the diaphragm as the vacuum alternately causes the diaphragm to move leftward until the port 36 opening is completely closed and then causes the rightward receding of the diaphragm a small distance to allow communication with the vacuum source.

In the FIG. 5 showing, vacuum has been applied to the port 32 causing the diaphragm to move to its leftward extreme. This is made possible by. the passage throughthe duck-bill valve 32 of the vacuum to move the diaphragm leftward, the stud 38 penetrating through the lips 34a of the valve in a union or copulation .as shown. At .this point, it does not matter whether vacuum is or isnot applied to port 36since that port is blocked by the roll-type diaphragm.

It should be noted that the stud 38 may take the form of a solid element 38 as shown in section in FIG. 7. Such an element which may be square or round in cross section will hold the lips 34a open to permit communication as long as the diaphragm is in the extreme leftward position shown.

From the position shown in FIG. 5, the diaphragm may be made to reassume the position in FIG. -4 by simply venting the line 32. This immediately causes the rightward movement of the diaphragm and stud 38 as atmospheric pressure enters the diaphragm chamber. With the stud 38 withdrawn from the lips 34a, (FIG. 4)lips 34a close and vacuum is restored within the diaphragm chamber as port 36 becomes unblocked by the roll-type diaphragm. Because the venting of the diaphragm chamber is controlled so that venting is cut off when the stud withdraws from the lips 34a, there is no overshooting by the diaphragm of the position shown in FIG. 4. This is a desirable characteristic and distinguishes from the motors of the prior art.

It is important in the embodiment of FIGS. 1, 4 and 5 that the length of the stud element 38 be such that in the rightward movement of the diaphragm the stud will have just withdrawn from the lips 34a permitting them to close as the port 36 opening becomes exposed permitting restoration of vacuum in the diaphragm chamber.

Valve means by which vacuum is applied to the

ports

32 and 36 to effect the desired control of the motor of the invention may be contrived by one skilled in the art. The example shown is in the form of a rotary valve 12. The housing 50 of the valve encloses a rotatable core 52 and appropriately mounts in its side wallthe vacuum source conduit 54, a conduit 56 communicating with the port 36, and a conduit 58 communicating with port 32. The core 52 is formed with a short circumferential channel 60 enclosed at either side (FIG. 2), and a circumferential channel 62 open at one side to permit venting.

In the valve position shown, the vacuum conduit 54 is blocked off by channel 60 and the

conduits

56 and 58 are vented. As the core 52 is rotated clockwise from the position shown, as by a suitable push button mechanism well known in the art, the next position will have the vacuum conduit 54 communicating through channel 60 with conduit 56 and port 36. The conduit 58 connecting port 32 will still be vented to the atmosphere through channel 62. This will cause the diaphragm to assume the position shown in FIG. 4 since the duck-bill valve 34 seals off the diaphragm chamber.

As the core 52 is rotated further, the vacuum conduit 54 is communicated to both

conduits

56 and 58 by channel 60. Hence, vacuum is applied to both

ports

36 and 32 causing the opening of valve 34 driving the diaphragm to the position in FIG. 5.

If the core 52 is next rotated counterclockwise a step, vacuum through conduit 54 then communicates only through conduit 56 to port 36, conduit 58 being vented. This causes the diaphragm to immediately and directly reassume the position shown in FIG. 4 since conduit 58 is vented through channel 62 until the stud 38 withdraws from the valve 34 permitting the lips 34a to close and vacuum is restored through port 36. Because of this operation which characterizes the invention, there is no sloppy undertravel or overshooting as the diaphragm returns from the extreme position in FIG. 5 to the intermediate position of FIG. 4. Such undertravel or overshooting had characterized prior devices in which the venting of the port 32 was accomplished by a remote venting valve.

Turning the core back to the position of FIG. 1 will cause venting of the

ports

32 and 36 so that the diaphragm will assume the position of FIG. 1.

MODIFICATION An improved motor embodying the invention is shown in FIGS. 8 and 9. In these figures, the primed form of the reference numerals used in FIGS. 1-7 are used to designate corresponding parts in the modified structure. While the form of the invention described above represents a marked improvement over prior devices, the FIGS. 8 and 9 embodiment provides even more reliable operation and is particularly useful where the environment is marked by severe temperature changes which might cause stretching or shrinking of the rubber diaphragm.

The operation of the FIGS. 8 and 9 embodiment is basically similar to that of the above-described structure, however, small differences in structure provide greater reliability. First, the actuating element or stud 38' has its attached end 80 slideably fitting into a recess 82 in the diaphragm mounting boss or stem 84. The recess 82 is longer than the enlarged end 80 of the stud so as to provide a lost-motion relation between the stud and the stem. A restriction 86 is formed in the diaphragm end of the recess to provide a stop for the lost-motion travel just as the end of the recess provides a stop in the other direction.

As a result of the structure described, the distance from the diaphragm 22' to the distal end of the stud is shorter as the diaphragm moves toward the end wall 18' than when it moves away. This is because the frictional engagement of the stud or probe with the valve 34' will cause the stud to move through its lost motion with respect to the stem 84. This means that as the diaphragm retreats from the extreme position to the intermediate position (as shown in FIG. 8), the added length of the probe will cause the diaphragm to move past the intermediate position toward the partial end wall 20' (to the position shown in phantom in FIG. 9) until the probe is completely out of the valve 34' to permit it to close. The port 36' will then be either partially or completely uncovered and will cause the diaphragm to reverse its travel and move leftward toward the wall 18, the probe telescoping through its lost motion, until the diaphragm reaches its true intermediate position as is shown in FIG. 9. At this true intermediate position, the edge of the diaphragm bears the relation to the port 36 as was described in connection with FIG. 1. This relationship holds with the structure of the FIG. 8,9 modifications irrespective of the amount of diaphragm stretching that has taken place, because in its last portion of movement the diaphragm is drawn back in a leftward direction to the true intermediate position by the vacuum of the port 36. By contrast, in the FIG. 4 version, as the diaphragm moves rightward from extreme to final intermediate position, the diaphragm will stop when the probe withdraws from the duck-bill 34 at which time the diaphragm, if it is elongated or stretched, for instance, could extend leftwardly well past the port 36 and completely seal it so that the subsequent venting of port 36 would not vent the chamber and the diaphragm would not immediately revert to the FIG. 1 or relaxed position.

In connection with the FIG. 8, 9 modification, it is important that the flow area through port 36' be smaller than the flow area through the valve 34' in order to make certain that the rate of air withdrawn from the diaphragm chamber through port 36' will be less than the rate of air entering through valve 34'. This assures that the diaphragm will go beyond the intermediate position to the point at which the probe completely withdraws from the valve and permits it to close, enabling the vacuum drawn through port 36' to draw the diaphragm to a stable intermediate position. If the opposite were true, or if the flows were equal during the overtravel, the diaphragm would come to rest or oscillate in a position at which air would simply flow through the chamber with both the valve 34 and the port 36 open.

The FIG. 8 and FIG. 9 versions incorporate the additional feature which is the stabilizing lip in the end wall 20'. This lip 90 steadies the boss 84 to avoid cocking of the diaphragm which might otherwise cause the probe 38 to approach valve 34 ofi' center so as to damage it. The actuating arm 40' is connected to the boss 84 in a connection which allows for some play as shown. The end of arm 40 is apertured and receives a neck adjacent the headed end 84a of the boss.

It should be clear that other variations of the structure are possible, though the preferred embodiments are shown.

The scope of the invention may be defined by the following claim language.

Iclaim:

l. A diaphragm-type vacuum motor having a housing, an end wall and a side wall in the housing, an end wall vacuum port in the housing, an outwardly directed duck-bill valve closing the port, a diaphragm in the housing, spring means urging the diaphragm away from the end wall, a stud carried by the diaphragm adapted to extend into and hold open the duck-bill as the port is vented until the diaphragm retreats from proximate the end wall to a locus intermediate the ends of its travel, and means adapted to selectively connect the port to a vacuum source or to atmosphere.

2. A diaphragm-type vacuum motor as described in claim 1 wherein a side wall vacuum port is provided to hold the diaphragm in an intermediate position at which the diaphragm partly covers the side wall port and the stud does not open the duck-bill valve.

3. A diaphragm-type vacuum motor as described in claim 2 wherein the intermediate position is closer to the end wall than the locus and the stud has a lost-motion mounting on the diaphragm.

4. A multiple-position vacuum motor comprising a. a housing having an end wall and a continuous side wall;

b. a port in the end wall and a port in the side wall at a point spaced from the end wall, the end wall port having a check valve oriented normally to pass flow of gas only from the interior of the housing out the end wall part but not the other way;

0. a movable element cooperating with the housing to form a chamber and adapted to assume at least two positions,

the first adjacent the end wall at which position the movable element covers the port in the side wall, and the second adjacent the side wall port at which the side wall port is at least partly uncovered;

d. means on the movable element for holding the check valve open while the movable element moves from the first position to the second position, said means not hold ing the check valve open when the movable member reaches the second position;

e. spring means for urging the movable element away from the end wall; and

f. means to connect the port selectively to a vacuum source or the atmosphere.

5. A multiple-position vacuum motor as described in claim 4 wherein the check valve is a rubber duck-bill valve and the means on the movable element is an elongated element supported on the movable element.

6. A multi-positon vacuum motor as described in claim 5 wherein the elongated element on the movable element is a stud which passes into and holds open the duck-bill valve.

7. A multi-position vacuum motor as described in claim 6 wherein the stud is mounted on the movable element with a lost-motion connection so that the side wall port is assuredly uncovered as the movable element moves past the second position before the duck-bill is allowed to close and then the vacuum may be applied through the port in the side wall so that the movable element is moved back to the second position.

8. A multi-position vacuum motor as described in claim 4 wherein the opening in the port in the side wall is of lesser area than the opening in the duck-bill so that when open it will not pass the amount of flow that the duck-bill will when it is held open by the stud.

9. A motor as described in claim 4 wherein the stud is tubular and open at its distal end and has an opening in its side in the motor and proximate the movable element.

10. A motor as described in claim 4 wherein the movable element is a roll-type diaphragm.

11. A motor as described in claim 4 wherein the means to connect is a rotary valve.

Claims

1. A diaphragm-type vacuum motor having a housing, an end wall and A side wall in the housing, an end wall vacuum port in the housing, an outwardly directed duck-bill valve closing the port, a diaphragm in the housing, spring means urging the diaphragm away from the end wall, a stud carried by the diaphragm adapted to extend into and hold open the duck-bill as the port is vented until the diaphragm retreats from proximate the end wall to a locus intermediate the ends of its travel, and means adapted to selectively connect the port to a vacuum source or to atmosphere.

4. A multiple-position vacuum motor comprising a. a housing having an end wall and a continuous side wall; b. a port in the end wall and a port in the side wall at a point spaced from the end wall, the end wall port having a check valve oriented normally to pass flow of gas only from the interior of the housing out the end wall part but not the other way; c. a movable element cooperating with the housing to form a chamber and adapted to assume at least two positions, the first adjacent the end wall at which position the movable element covers the port in the side wall, and the second adjacent the side wall port at which the side wall port is at least partly uncovered; d. means on the movable element for holding the check valve open while the movable element moves from the first position to the second position, said means not holding the check valve open when the movable member reaches the second position; e. spring means for urging the movable element away from the end wall; and f. means to connect the port selectively to a vacuum source or the atmosphere.