AU2008228616B2

AU2008228616B2 - Housing with a switch shaft that can be disconnected

Info

Publication number: AU2008228616B2
Application number: AU2008228616A
Authority: AU
Inventors: Elena Kondrus
Original assignee: R Stahl Schaltgeraete GmbH
Current assignee: R Stahl Schaltgeraete GmbH
Priority date: 2007-03-22
Filing date: 2008-02-05
Publication date: 2011-09-15
Anticipated expiration: 2028-02-05
Also published as: DE102007013689B3; AU2008228616A1; WO2008113429A1; EP2135267A1; EP2135267B1

Abstract

The invention relates to a housing of the explosion-proof enclosure type, which is provided with an actuating shaft that is rotatably mounted to form an explosion-proof gap in the wall of the housing. A two-part coupling is provided as a coupling for an electromechanical element in the housing, one part being provided on the actuating shaft and the other part on the electromechanical component.

Description

1 HOUSING WITH A SWITCH SHAFT THAT CAN BE DISCONNECTED Technical Field The present invention relates to housings for electrical equipment. More 5 particularly, the present invention relates to an explosion-proof housing. Background of the InVertion In a number of flameproof housing, switches that are arranged within the housing must be externally actuated. The housings are made with a type of flameproof protection such that the switch shaft must be supported in the housing with a flameproof 1o joint. During the assembly of such housing, significant manufacturing problems arise if the switch is to be mounted in the body of the housing and it is required that the switch shaft extend through the cover. Object of the Invention 1s It is the object of the present invention to substantially overcome or at least ameliorate one or more of the problems of the prior art. Summary of the Invention According to one aspect of the present invention, there is provided an explosion proof housing for electrical equipment, the housing comprising: 20 a body; a cover that is attached to the body and that defines a flameproof interior together with the body; an electromechanical device that is arranged in the interior and actuated by a drive shaft; 25 a bore; an actuating shaft that extends through the bore, that forms a flameproof joint together with the bore and that can be axially displaced in the bore, and wherein the actuating shaft is provided with an actuating handle, and wherein the actuating shaft is positively secured against an axial movement in the axial direction when the actuating 30 handle is in the switch on-position; and a positive coupling that features two coupling halves, wherein one coupling half is connected to the drive shaft without rotational play and the other coupling half is connected to the actuating shaft without rotational play, and wherein said coupling can be 2 coupled or decoupled by moving the actuating and drive shafts in the longitudinal direction of the actuating and drive shafts. Preferably, the coupling is realized in such a way that coupling halves can only be coupled to one another in a single position relative to a full revolution. 5 Preferably, one coupling half features a groove and the other coupling half features a rib that is realized complementarily to the groove. Preferably, the groove is arranged asymmetrically relative to the axis of the shaft. Preferably, means are provided for maintaining the engagement between the coupling halves. 10 Preferably, the means comprises a spring. Preferably, the spring is a compression spring. Preferably, the actuating shaft is guided in the bore in an axially displaceable fashion. Preferably, the bore is arranged in the cover. 1s Preferably, the bore extends through a bushing that is interested into the housing. Preferably, a partially cylindrical collar is provided on the outer side of the housing adjacent to the bore and cooperates with a corresponding recess in the actuating handle in order to limit the rotational movement. Preferably, the collar features an appendage that points in the circumferential 20 direction and is designed for cooperating with a recess on the actuating handle in order to prevent the actuating shaft from being pulled out when the actuating handle is located in one of the end positions. Brief Description of the Drawings The following description of the figures elucidates aspects for understanding the 25 invention. A person skilled in the art can in the usual way deduce other details froin the drawings that are not described and that supplement the description of the figures in this respect. It should be clear that numerous modifications are possible. The figures described below are not necessarily drawn to scale, wherein certain regions may be enlarged in order to elucidate details. Furthermore, the figures are 30 strikingly simplified and do not contain every detail that may be present, if applicable, in the practical embodiment. An embodiment of the present invention is illustrated in the figures. Figure 1 shows, in a perspective view, a housing with a type of flameproof protection; 3 Figure 2 shows, in an exploded perspective view, the drive mechanism for a packet cam switch arranged in the housing; Figure 3 shows, in an enlarged perspective view, the collar tha surrounds the actuating shaft; and. 5 Figure 4 shows a bottom view of the actuating knob. Detailed Description Figure 1 shows, in a perspective view, a housing 1 that is realized with a type of flameproof protection. The housing 1 is composed of a body 2 and a cover 3, which is screwed to the body 2 with the aid of several screws 4. o0 The housing I serves for accommodating electronic and electromechanical components in its interior in accordance with a type of flameproof protection, for example, a packet cam switch 5, which is indicated by broken lines and features a switch shaft 6. The switch shaft 6, illustrated discontinuously, is externally actuated by means of a rotary knob 7, which is coupled to the switch shaft 6 without rotational play. The 1s manner in which the rotary knob 7 is coupled to the switch shaft 6 is illustrated in the exploded perspective view according to Figure 2. The main components that mechanically connect the rotary knob 7 to the packet cam switch 5 include a positive coupling 8, an actuating shaft 9, a bushing 11 that is interested into the cover 3 and a collar arrangement 12 situated on the outer side of the 20 cover 3. The bushing 1 is provided with threads (not shown) on its end that faces the cover 3, and is screwed into corresponding threads in the interior of the cover 3, and is sealed with an adhesive. The screw connection between the bushing I and the cover 3 is thereby made flameproof. 25 The inner end of the housing 1I is provided with a hexagonal attachment 13 in order to screw the bushing 1 1 into the cover 3. A cylindrical bore 14 that extends through the bushing 1 1 has an inside diameter that corresponds to the outside diameter of the continuously cylindrical actuating shaft 9 of constant diameter. The bore 14 forms a flameproof joint together with the cylindrical so actuating shaft 9. On its end that faces the actuating knob 7, the actuating shaft 9 transitions into a drive square 16 that contains a coaxial threaded blind hole17 in its center. The actuating shaft 9 contains a circumferential annular groove 18 for retaining ring 19 at a distance 3a from the drive square 16, the dimensions of which infthe diagonal direction are smaller than the outside diameter of the actuating shaft 9. The remote end of the actuating shaft 9 relative to the drive square 16 is connected with rotational play to a coupling half 21 that forms part of the coupling 8. 5 The coupling half 21 consists of an essentially cylindrical structure with an outside diameter that is larger than the outside diameter of the actuating shaft 9. A grove 22 of rectangular cross section transversely 4 extends through the coupling half 21. The groove 22 is positioned asymmetrically relative to the longitudinal axis of the cylindrical actuating shaft 9. Since the coupling half 21 has a larger outside diameter than the actuating shaft 9, an annular shoulder surface 23 is formed that acts as an abutment for a helical compression spring 24. The clear width of the helical compression spring 24 is slightly larger than the outside diameter of the actuating shaft 9. On the other end, the helical compression spring 24 is supported on the inwardly directed end of the bushing 11 at the hexagonal attachment 13. The coupling 8 also comprises a second coupling half 25 that is connected to the switch shaft 6 without rotational play. The coupling half 25 carries a rib 26 that protrudes in the axial direction and is realized complementarily to the groove 22 or slot 22. This rib 26 also has a slight radial offset relative to the longitudinal axis of the switch shaft 6. Thus, the two coupling halves 21 and 25 can only be engaged with one another in a single rotational position. Figure 3 shows a detail of the collar arrangement 12 situated on the outer side of the cover. This collar arrangement comprises a flange plate 28 with two lateral bores 29, through which mounting screws extend in order to fix the collar 12 on the outer side of the cover 3. A partially cylindrical collar 31 that concentrically surrounds a continuous bore 32 over an azimuth angle of approximately 1800 rises from the flange plate 28. The bore 32 is aligned with the through-bore 14 in the bushing 11. On one end, the collar 31 forms a lug 33 that points in the circumferential direction and defines a recess 34 between itself and the flange plate 28. The recess 34 is open in the circumferential direction. According to Figure 4, the underside of the toggle knob 7 is provided with a pocket shaped cavity 35 or milled recess, the clear width of which is greater than the outside diameter of the collar 31. The toggle knob 7 contains a continuous square opening 36 that is adapted to the drive square 16 in an extension of the cavity 35. An appendage 37, the axial dimension or height of which corresponds to the height of the recess 34 of the collar 31, laterally projects into the cavity 35. The arrangement functions as described below: The packet cam switch 5 is provided with the coupling half 25 on its switch shaft 6. For this purpose, the cylindrical part of this coupling half may contain a corresponding blind bore, by means of which the coupling half is arranged on the switch shaft 6. Another option consists of already realizing the corresponding end of the switch shaft 6 in the form of a coupling half 25 with a rib 26. During assembly, the packet cam switch 5 is placed into the body 2 of the housing I together with all other electronic and electromechanical components. 267744gcrmanapplication.doc 5 The cover 3 is fitted with the actuating shaft 9 before the cover 3 is installed on the body 2. For this purpose, the helical compression spring 24 is pushed onto the actuating shaft 9 from the end with the drive square 16. Subsequently, the actuating shaft 9 provided with the helical compression spring 24 is inserted into the bore 14 of the bushing I1 from the inner side of the as yet uninstalled cover 3. The insertion is continued against the effect of the helical compression spring 24 in order to insert the retaining ring 19 into the annular groove 18. The collar arrangement 12 is then screwed onto the outer side of the cover with the aid of screws (not shown). The collar 31 of the collar arrangement 12 now semi-circularly surrounds the section of the actuating shaft 9 that protrudes over the outer side of the cover 3 and is prestressed in the direction of the housing, i.e., toward the right relative to Figure 2, by the helical compression spring 24. Subsequently, the actuating knob 7 is attached to the drive square 16 in the corresponding rotational position and secured on the drive square 16 with the aid of a through screw 38 that is screwed into the threaded bore 17. After the cover 3 is fitted in this way, it is positioned on the body 2 and secured with the aid of the screws 4. By turning the actuating knob 7 accordingly, the coupling half 21 is correspondingly moved into a position in which the rib 26 can penetrate the slot 22. The two coupling halves 21 and 25 are thereby engaged with one another. The two coupling halves 21 and 25 are pushed together by means of a compression spring 24 that constantly prestresses the actuating shaft 9 in the direction of the coupling half 25. The description clearly indicates that the axial stroke of the actuating shaft 9 must be slightly larger than the depth of penetration of the rib 26 into the slot 22 such that the cover 3 can still be screwed to the body 2 if the arrangement is not perfectly aligned. After assembly, the desired coupling between the actuating knob 7 and the packet cam switch 6 is produced by turning the actuating knob 7 in the direction illustrated in Figure 1. It is assumed that the position of the actuating knob shown in Figure 1, in which the wings provided on the actuating knob 7 are positioned vertically, corresponds to the off position. In this position of the actuating knob 7, the actuating knob 7 can theoretically be pulled out by a certain distance together with the actuating shaft 9 such that in this case the two coupling halves 21 and 25 would be decoupled from one another. In order to move the packet cam switch 6 to the on position, the actuating knob 7 must be turned in the clockwise direction, for example, by an eighth of a turn. Due to this rotation, the appendage 37 is moved into the region of the recess 34 underneath the projection 32. This prevents the coupling 8 from being decoupled by pulling on the actuating knob 7 in the on position of the packet cam switch 5. A rotation of the knob 7 in the opposite direction can also be prevented, for example, due to the shape of the collar 31. 267744germanapplication.doc 6 If it is suspected that, due to its geometry, the collar 31 could block the rotation of the knob 7 needed to realize the coupling, it is sufficient to realize the axial stroke of the actuating shaft 9 so that it is large enough that the actuating knob 7 with its appendage 37 can be pulled out beyond the collar 31 in the axial direction. A housing with a type of flameproof protection is provided with an actuating shaft that is rotatably supported in the wall of the housing such that a flameproof joint is formed. A two-part coupling is provided in order to realize the coupling with an electromechanical element in the housing, wherein one part of said coupling is provided on the actuating shaft and the other part is provided on the electromechanical component. 267744gemianapplication.doc

Claims

1. An explosion-proof housing for electrical equipment, the housing comprising: 5 a body; a cover that is attached to the body and that defines a flameproof interior together with the body; an electromechanical device that is arranged in the interior and actuated by a drive shaft; .10 a bore; an actuating shaft that extends through the bore, that forms a flameproof joint together with the bore and that can be axially displaced in the bore, and wherein the actuating shaft is provided with an actuating handle, and wherein the actuating shaft is positively secured against an axial movement in the axial direction when the actuating 15 handle is in the switch on-position; and a positive coupling that features two coupling halves, wherein one coupling half is connected to the drive shaft without rotational play and the other coupling half is connected to the actuating shaft without rotational play, and wherein said coupling can be coupled or decoupled by moving the actuating and drive shafts in the longitudinal 20 direction of the actuating and drive shafts.

2. The housing according to Claim 1, wherein the coupling is realized in such a way that coupling halves can only be coupled to one another in a single position relative to a full revolution. 25

3. The housing according to Claim 1, wherein one coupling half features a groove and the other coupling half features a rib that is realized complementarily to the groove. 30

4. The housing according to Claim 3, wherein the groove is arranged esymmetrically relative to the axis of the shaft.

5. The housing according to Claim 1, wherein means are provided for maintaining the engagement between the coupling halves. 35 8

6. The housing according to Claim 5, wherein the means comprises a spring.

7. The housing according to Claim 6, wherein the spring is a compression 5 spring.

8. The housing according to Claim 1, wherein the actuating shaft is guided in the bore in an axially displaceable fashion. 10

9. The housing according to Claim 1, wherein the bore is arranged in the cover.

10. The housing according to Claim 1, wherein the bore extends through a . bushing that is interested into the housing. * 15

11. The housing according to Claim 1, wherein a partially cylindrical collar is provided on the outer side of the housing adjacent to the bore and cooperates with a corresponding recess in the actuating handle in order to limit the rotational movement. 20

12. The housing according to Claim 11, wherein the collar features an appendage that points in the circumferential direction and is designed for cooperating with a recess on the actuating handle in order to prevent the actuating shaft from being pulled out when the actuating handle is located in one of the end positions. 25

13. A housing substantially as hereinbefore described with reference to the accompanying drawings. Dated 18 August, 2011 R. Stahl Schaltgerate GmbH 30 Patent Attorneys for the Applicant/Nominated Person SRUSON & FERGUSON