US3824903A

US3824903A - Vacuum control drive

Info

Publication number: US3824903A
Application number: US00308462A
Authority: US
Inventors: J Hahn
Original assignee: Behr GmbH and Co KG
Current assignee: Mahle Behr GmbH and Co KG
Priority date: 1971-11-26
Filing date: 1972-11-21
Publication date: 1974-07-23
Anticipated expiration: 1991-07-23
Also published as: GB1364158A; IT971209B; FR2160964A1; FR2160964B1; DE2158786A1

Abstract

A two-stage vacuum control drive is disclosed in which a vacuum control drive, consisting of a roll membrane movably mounted to counteract the action of a spring under the influence of a vacuum, is mounted displaceably in the housing of a second similar vacuum control drive. The two drives are controlled independently and have a cumulative effect on the total travel of the device.

Description

United States Patentv [191 Hahn 1 July 23, 1974 VACUUM CONTROL DRIVE 3,090,359 5/1963 Hoppenstand 92/64 x Inventor: Johann Hahn, Stuttgart Germany 3,683,753 8/1972 Johnson M 92/48 [73] Assignee: Suddeutsche Kuhlerfabrik Julius Fr.

Behr, Stuttgart, Germany Primary Examiner-Edgar W. Geoghegan Assistant ExaminerAbraham Hershkovitz [22] Flled: 1972 Attorney, Agent, or Firm-Browdy & Neimark [21] Appl. No.: 308,462

[30] Foreign Application Priority Data 57 TR T Nov. 26, 1971 Germany 2158786 A two-stage vacuum control drive is disclosed in Cl r which a vacuum control drive, consisting of a roll 9 membrane movably mounted to counteract the action [51] Int. Cl. FOlb 19/00 of a spring under the influence of a vacuum, is [58] Fle d of Sea ch 92/ mounted displaceably in the housing of a second simi- 167 lar vacuum control drive. The two drives are controlled independently and have a cumulative effect on [56] References Cited the total travel of the device.

UNITED STATES PATENTS 3,081,134 3/1963 14 Claims, 2 Drawing Figures Masser 91/167 X PATENTEDJULZMQN 3,824,903

SHEU 2 [IF 2 l VACUUM CONTROL DRIVE FIELD OF THE INVENTION The invention concerns a vacuum control drive, especially for automatic ormanual remote control in motor vehicles, as for example automatic control of heater circuits, with vacuum control units in which a spring-loaded roll membrane or the like is displaceable under the influence of a vacuum in a housing.

BACKGROUND OF THE INVENTION Vacuum control drives, in which a roll membrane is movably mounted to counteract the action of a spring under the influence of a vacuum in the usually bipartite sometimes cylindrical housing, are known.

The corresponding control elements are therefore movable, especially displaceable, within a certain range, which corresponds roughly to the travel of the roll membrane.

It is also known to connect two or more vacuum sources to the control, or, in order to increase'the effective travel to use two essentially identical vacuum control drives of the above-described type and to 'lin them by a suitable coupling.

The expenditure of labor required to make and assemble these'prior art double control drives is very great, however.

Hence, the object of the invention is to make a twostage vacuum control drive that is simple to make and assemble and in particular requires only a small amount of space. 7

SUMMARY OF THE INVENTION This goal is achieved according to the invention primarily by the fact that in a vacuum control drive of the type described above, a first vacuum control drive in a housing is mounted displaceably in the housing of a second vacuum control drive.

Thus, it is advantageously brought about that the two vacuum control drives are each operated and controlled independently of each other from a connected vacuum source, and the resultant travel is the total effect of the two active vacuums.

It is especially advantageous if a retaining section is mounted displaceably in an intermediate section, said retaining section beingconnected .to an upper part of the housing holding one edge of the roll membrane, while a lower part of the housing holding a second roll membrane is connected to the intermediate section. This arrangement allows an advantageous telescopelike displaceability of one vacuum control drive stage relative to the other.

According to a first sample embodiment of the invention, a connecting stub is provided in the housing of the retaining section for connection of the vacuum to the upper control drive and a longitudinal slot is provided in the intermediate section as a passageway and guide for the connecting stub.

The longitudinal slot thus serves advantageously simultaneously as an upper stop and as a guide for the upper control drive in the housing of the lower vacuum drive.

Advantageously, fastening means are provided in the lower part of the housing to connect the control drive with other structural elements.

The lower part of the housing of the lower vacuum control drive has a preferably central connecting stub for the vacuum connection and a torus as a support for a membrane counter spring.

According to a further feature of the invention, it is especially advantageous if the lower part of the housing and floor section of the retaining section each have a circular stop as a stroke limiting device for the roll sleeves, which interact with the preferably vulcanized stop plates mounted in the upper parts of the roll sleeves.

An embodiment that is structurally especially advantageous is obtained if the retaining section and lower housing section each have a bead that fits into the upper part of the housing and/or the intermediate sec tion and ensures a tight seal by means of elastic clamping elements. The tight seal may further be ensured by rolling, caulking or spraying.

According toa second sample embodiment of the invention, the lower part of thehousing has two vacuum connection openings, one of which is connected to the upper control drive by a flexible connection.

It is especially advantageous if a rubber or plastic tube is used as the connection, said tube being connected to a preferably'centrally located opening in the stop plate of the lower roll membrane and simultaneously to the floor of the retaining section.

As stops, it is advantageous to use circular disks in a groove in the floor of the retaining section and in a flange on the lower part of the housing.

According to an improvement of the invention, the spring tension of the spring in the lower stage is set different from the spring tension of the spring in the upper stage. It is especially advantageous if the tension of the lower spring is greater than the tension of the upper spring in the compressed state.

In a second improvement it is especially advantageous if the fastening means is mounted laterally on the housing.

BRIEF DESCRIPTION OF THE DRAWINGS Further advantages and features of the invention will be described in the reference to the drawing, which shows two sample embodiments in schematic form:

FIG. 1: A side elevation partly in section showing a first sample embodiment with a side connection for the upper control drive, and

FIG. 2: A side elevation partly in section showing a second sample embodiment of the invention with essentially parallel connecting stubs for the vacuum connections of both control drives.

DESCRIPTION OF PREFERRED EMBODIMENTS FIG. 1 shows a first sample embodiment of the invention with the left half in cross section and the right half in outside view and turned through approximately The two-stage vacuum control drive according to the invention consists of a retaining section 1 with an upper part 2, an intermediate section 3 and a lower housing section 4. Retaining section 1 and upper housing section 2 in the floor 20 of retaining section 1 form the housing for the first stage I of the vacuum control drive. An intermediate section 3 with lower housing section 4, on the other hand, together with the floor 20 of re taining section 1, form the housing for the second, lower stage II of the two-stage vacuum control drive according to the invention. The upper first stage I has a connecting stub 5, mounted somewhat radially and laterally in the lower part-of retaining section 1. lnterme- 3 diate section 3 has a slot 14 in which the connecting stub is displaceable in a concentric manner. Slot 14 serves to guide connecting stub 5, while the upper end of slot 14 serves as a stop for retaining-section 1 in cooperation with connecting stub 5.

Between a circular flange of the retaining section 1 and a circular housing 26 of the upper housing section 2, the edge of an upper roll membrane is clamped with interposition of an upper sealing ring 8. Elastic fastening clamps l2 serve to ensure a tight seal. The tight seal may further be ensured by rolling, caulking or spraying. This roll membrane is pressed upward against an upper spring 17 that rests on floor of retaining section 1 against a circular stop 19, as shown in the drawing. The upper seal consists of an upper end plate 24, connected in suitable fashion to a control element 28. The floor 20 of retaining section 1 has a circular bearing surface that serves as the stop for the movement of the upper roll membrane 15 and/or the upper end plate 24.

In the lower housing section 4 a connectingstub 6 is provided for the vacuum to the lower vacuum control drive stage II. In addition, fastening means 7' and 7" can be formed on it.

The intermediate section 3 is again clamped in an annular flange on the lower housing section 4 with a circular housing 27, with interposition of a lower sealing ring 9. Elastic fastening clamps 12 serve for a tight connectiomThe tight seal may further be ensured by rolling, caulking or spraying. Further, a stop-ring-plate 13 is provided between the annular flange 11 and the circular housing 27. A lower roll membrane 16 is pressed upward on the one hand by spring 18 which bears against a lower circular stop 21 on the lower housing section 4 (in the drawing), and is clamped with its edge between the annular flange l1 and the circular housing. In the upper part of the roll membrane 16 a lower end plate 25 is provided, preferably vulcanized. This end plate interacts with a circular lower bearing 23 in the lower housing section 4.

A two-stage vacuum control drive according to the invention and in'the sample embodiment in FIG. 1

works as follows:

The vacuum connections 5 and 6 are connected in the appropriate corresponding vacuum sources. If for example the upper stage I is evacuated first, roll membrane 15 is pulled downwards against the action of a spring 17. The travel is determined only by the distance between the edge of the upper circular stop 22 and the upper housing section 2. In a control drive that was constructed, this travel was 26 mm.

Regardless of the vacuum in stage I, a vacuum can be created in the lower stage II via the connecting stub 6. Then the lower roll membrane 16 is displaced downward against the action of spring 18. In this movement, the lower roll membrane 16 carries down along with it the floor of retaining section I, linked and/or vulcanized together with the lower end plate 25. The result is a telescopic displacement of retaining section 1 inside intermediate section 3. The connecting stub 5 for the vacuum connection to upper stage I participates in the movement. The travel is limited on the one hand by the distance of the floor 20 from the upper surface of the lower circular bearing 23, as shown schematically in the drawing. On the other side of the upward travel is limited by the upper edge of slot 14. It is immaterial for the manner of action of the control drive whether first the upper stage I and then the lower stage II are controlled by the vacuum or vice versa. In fact, the possibility exists to evacuate both stages simultaneously.

Thus, when a vacuum is applied to connection 5 in the sample embodiment according to FIG. 1, mem- If a vacuum is applied to both connection 5 and connection 6, membrane 15 is displaced in upper stage I because of the vacuum applied to connection 5 and remains in the same position with respect to housing sections 1 and 2, even when the vacuum applied to connection 6 displaces housing 1, 2 with 20 downward as a unit.

It'is especially advantageous if the spring tension or spring l8 if the lower stage ismade greater than the spring tension of spring 17 of the upper stage I in the compressed state. In the constructed sample described above the travel of the lower stage was 14 mm, so that the total travel was approximately 40 mm.

Each stage is sealed off by the clamped and/or vulcanized roll membranes 15 and 16. It is possible to use identical roll membranes in both stages, but with different amounts of travel. 7

Retaining section 1 with upper housing section 2, as mentioned above, is connected to lower roll membrane 16 via floor 20. With a total travel of approximately 40 mm the constructed example only has an overall height of 75 mm.

FIG. 2 shows a modified sample embodiment in which the vacuum connection for the upper stage I is no longer located laterally but in the floor of the control drive. I I

The construction of the control drive according to the sample embodiment in FIG. 2 essentially corresponds to the construction according to the sample embodiment in FIG. 1. A retaining section 31 is provided with an annular flange 40 and tightly sealed to the upper housing section 32 with interposition of an upper sealing ring 38. A roll membrane 45 is' tightly clamped between the annular flange 40 and a circular housing 58 on the upper housing section 32. Th roll membrane 45 is pressed upward by a spring 47, which bears on an upper annular notch 49 in bottom 50 of retaining section 31 (in the drawing). It has an upper connecting plate 54. The travel is mainly limited by a circular upper bearing 52 in the floor 50 of holder 31. Annular flange 40 and upper circular housing 58 may be provided with notches 42 for fastening clamps (not shown), similar to the elastic fastening clamps 12 in FIG. 1, said notches being arranged at intervals around the edge. The connection between the lower annular flange 41 of a floor 34 and a lower circular housing 59 of an intermediate section 33 is achieved in similar fashion. Intermediate section 33 is closed off by a lower tion of a lower sealing ring 39 and a strike-ring-plate 43. This lower roll membrane 46 is pressed upward by a lower spring 48 that bears on a circular lower bearing 53 (in the drawing). In the upper area of the lower roll membrane 46 a lower end plate 55 is provided, preferably vulcanized. The lower end plate 55 has a connecting opening 60 (preferably central) for the vacuum. An elastic connection 56 made of rubber or plastic is connected to this connection 60, the other end of said elastic connection being connected to connecting stub 35 for stage I.

A lower torus 51 serves as a bearing for the lower end plate 55 of the lowerroll membrane 46. The upper bearing is an end plate 44 connected to retaining sec tion 31. This upper end plate 44 interacts with the lower end circular bearing plate 53.

The floor 50 of retaining section 31 is firmly connected to the lower roll membrane 46 and/or the lower end plate 55 by a connecting piece 56.

Fastening means not shown in detail may be inserted, screwed or fastened in another suitable fashion to connectors 37.

The manner of operation of the sample embodiment according to FIG. 2'essentially corresponds completely to the manner of operation of the sample embodiment according to FIG. 1. The sole difference is that the placement of the connection for the vacuum to the upper stage I is shifted from the outer wall to the total housing, so that no external movable connections are required.

The invention is not limited to the sample embodiment shown and described. It includes as well all modifications by experts in the field and partial as well as subcominations.

1. In a vacuum control drive including a housing,'a spring-loaded roll membrane displaceably mounted in said housing for displacement under the action of a vacuum and a connection means for connecting the drive to a source of vacuum, the improvement wherein:

the drive comprises two stages, the

prising a first housing,

a first spring-loaded roll membrane displaceably mounted in said first housing for displacement under the action of a vacuum, and

a first connection means for connecting said first stage to a source of vacuum,

said first'housing comprising a retaining section and an upper housing section connected thereto, said first roll membrane being connected to said first housing between said retaining section and said upper housing section; and

the second stage comprising a second housing,

a second spring-loaded roll membrane displaceably mounted in said second housing for displacement under the action of a vacuum, and

a second connection means for connecting said second stage to a source of vacuum,

said second housing comprising an intermediate section and a lower housing section connected thereto, said second roll membrane being connected to said second housing between said intermediate section and said lower housing section;

first stage comwherein said retaining section is displaceably mounted in said intermediate section such that said first housing and said first roll membrane of said first stage are displaceably mounted with said second housing for displacement in conjunction with the displacement of the second roll membrane.

2. Control drive according to claim 1, wherein said first connecting means comprises a connecting stub connected to said retaining section and said intermediate section includes a lengthwise slot acting as a passageway and guide for said connecting stub.

3. Control drive according to claim 1, further including fastening means in said lower housing section.

4. Control drive according to claim 1 wherein said retaining section and said lower housing section each have a flange that is overlapped respectively by said upper housing section and said intermediate section and further wherein said first and second stages each further include an elastic clamping means for ensuring a tight seal at said overlapped flanges.

5. Control drive according to claim 4 wherein the tight seals are further ensured by rolling, caulking, or spraying.

6. Control drive according to claim 1, further including laterally affixed fastening means on the housing.

7. A control drive in accordance with claim 1 wherein said second spring-loaded roll membrane comprises a second roll membrane and a second counter spring, wherein said lower housing section includes a torus as a supporting bearing for said second counter spring, and wherein said second connecting means comprises a central connecting stub connected to said lower housing section.

8. A control drive in accordance with claim 1 wherein said first spring loaded roll membrane further includes a first end plate connected to the portion of said first roll membrane opposite that portion thereof connected to said first housing, wherein said second spring loaded roll membrane further includes a second end plate connected to the portion of said second roll membrane opposite that portion thereof connected to said second housing, wherein said retaining section includes a first circular bearing menus for limiting the travel of said first end plate, and wherein said lower housing section includes a second circular bearing means for limiting the travel of said second end plate.

9. A control drive in accordance with claim 8 wherein said first and second end plates are vulcanized.

10. A control drive in accordance with claim 1 wherein said first and second connection means respectively comprise first and second connecting stubs, both connected to said lower housing section, said first connection means further including an elastic connection between said retaining section and said first connecting stub.

11. Control drive according to claim 10, wherein circular bearing plate means for stopping the travel of said second roll membrane are mounted in a groove within the bottom of said retaining section and on a flange on the lower housing section.

12. A control drive in accordance with claim 10 wherein said second spring-loaded roll membrane further includes a second end plate connected to the portion of said second roll membrane opposite that portion 8 spring and wherein said two counter springs are set differently.

14. Control drive according to claim 13, wherein the spring tension of the counter spring in said second stage is set greater than the spring tension of the counter spring in said first stage in the compressed state.

Claims

1. In a vacuum control drive including a housing, a springloaded roll membrane displaceably mounted in said housing for displacement under the action of a vacuum and a connection means for connecting the drive to a source of vacuum, the improvement wherein: the drive comprisEs two stages, the first stage comprising a first housing, a first spring-loaded roll membrane displaceably mounted in said first housing for displacement under the action of a vacuum, and a first connection means for connecting said first stage to a source of vacuum, said first housing comprising a retaining section and an upper housing section connected thereto, said first roll membrane being connected to said first housing between said retaining section and said upper housing section; and the second stage comprising a second housing, a second spring-loaded roll membrane displaceably mounted in said second housing for displacement under the action of a vacuum, and a second connection means for connecting said second stage to a source of vacuum, said second housing comprising an intermediate section and a lower housing section connected thereto, said second roll membrane being connected to said second housing between said intermediate section and said lower housing section; wherein said retaining section is displaceably mounted in said intermediate section such that said first housing and said first roll membrane of said first stage are displaceably mounted with said second housing for displacement in conjunction with the displacement of the second roll membrane.

8. A control drive in accordance with claim 1 wherein said first spring loaded roll membrane further includes a first end plate connected to the portion of said first roll membrane opposite that portion thereof connected to said first housing, wherein said second spring loaded roll membrane further includes a second end plate connected to the portion of said second roll membrane opposite that portion thereof connected to said second housing, wherein said retaining section includes a first circular bearing menns for limiting the travel of said first end plate, and wherein said lower housing section includes a second circular bearing means for limiting the travel of said second end plate.

12. A control drive in accordance with claim 10 wherein said second spring-loaded roll membrane further includes a second end plate connected to the portion of said second roll membrane opposite that portion thereof connected to said second housing, said second end plate having a hole therein and wherein said elastic connection comprises a rubber or plastic tube, said tube passing through and connecting with said hole in said second end plate.

13. A control device in accordance with claim 10 wherein said first and second spring-loaded roll membranes each comprise a roll membrane and a counter-spring and wherein said two counter springs are set differently.