US3790921A

US3790921A - Electric connecting device for an encased refrigerating machine

Info

Publication number: US3790921A
Application number: US00198205A
Authority: US
Inventors: E Nielsen; H Pedersen
Original assignee: Danfoss AS
Current assignee: Danfoss AS
Priority date: 1970-11-10
Filing date: 1971-11-12
Publication date: 1974-02-05
Anticipated expiration: 1991-02-05
Also published as: AU3545071A; DE2055184C2; CA933270A; BR7107494D0; DE2055184A1; IT940049B; ES396819A1; FR2113704A5

Abstract

The invention relates to an electrical housing assembly for a refrigeration machine which attaches to the casing wall of the refrigeration machine. The housing assembly encloses a plug element which is mounted on insulated guide pins which extend through the casing wall. The housing assembly comprises a plastic box which surrounds the plug element and a U-shaped spring for attaching the cover to the casing wall. Attaching means for the spring include guide track elements having hooking edges which facilitate the easy snapping of the spring into and out of its attached position.

Description

United States Patent [191 Nielsen et al.

[ Feb. 5, 1974 1 ELECTRIC CONNECTING DEVICE FOR AN ENCASED REFRIGERATING MACHINE [75] Inventors: Erik Nielsen; Hans Christian Pedersen, both of Nordborg, Denmark [73] Assignee: Danioss A/S, Nordborg, Denmark [22] Filed: Nov. 12, 1971 [21] Appl. No.: 198,205

[30] Foreign Application Priority Data Nov. 10, 1970 Germany P 20 55 184.2

[52] US. Cl. 339/75 R, 339/125 R, 174/67 [51] Int. Cl H011 13/54 [58] Field of Search 174/48, 67; 339/36, 75, 82, 339/125, 126, 128

[56] References Cited UNITED STATES PATENTS 2,869,098 l/l959 Sauer 339/128 X 3,239,794 3/1966 Roelsgaard et al. 339/126 RS X 3,49l,327 l/l970 Tait et al. 339/75 P X Primary Examiner-Richard E. Moore Attorney, Agent, or Firm-Wayne B. Easton ABSTRACT The invention relates to an electrical housing assembly for a refrigeration machine which attaches to the casing wall of the refrigeration machine. The housing assembly encloses a plug element which is mounted on insulated guide pins which extend through the casing wall. The housing assembly comprises a plastic box which surrounds the plug element and a U-shaped spring for attaching the cover to the casing wall. Attaching means for the spring include guide trackelements having hooking edges which facilitate the easy snapping of the spring into and out of its attached position.

2 Claims, 4 Drawing Figures 1 ELECTRIC CONNECTING DEVICE FOR AN ENCASED REFRIGERATING MACHINE The invention relates to an electric connecting device for an encased refrigerating machine, which device comprises a plug element carrying a terminal and mounted on guide pins which extend through and are insulated against the casing wall, a holder secured to the casing, and a cap which covers the plug element and is detachably applied to the holder by means of a fixing element. 1

It is known practice to fit various functional compo nents to the plug element, e.g., the starting relay for the motor of the refrigerating machine and an excess temperature protective cut-out. The cap prevents contact with the electrical components. It is secured to a complementary holder by means of at least one screw. The holder consists of a shaped sheet-metal part securely welded to the casing. The screw has been considered to be necessary so that the cap does not become detached as a result of the continuous vibration of the casing. The fitting and removal of the cap however causes difficulties particularly when, as is the usual practice, the casing has already been fitted in a cold cabinet and is not therefore fully accessible. The screw has to be introduced into the associated tapped part and can easily get lost. If it is located at a point difficult of access, the large number of turns of the screw-driver necessary for tightening and loosening the screw, as well as the need for fully tightening it cause considerable trouble.

The object of the invention is to provide an electric connecting device of the initially stated kind which can be attached and released considerably more easily but nevertheless ensures that the cap fits securely on the casing.

According to the invention, this object is achieved by the fixing element being constituted by a substantially U-shaped spring which straddles the cap, engages behind stop faces on the holder by means of outwardly bent hooks at its free ends, and has a central web which resiliently urges the cap against an abutment surface on the casing, by the side walls of the cap incorporating a guide track for the limbs of the spring, said track being provided with a bridge element, and by the limbs of the spring each incorporating an outwardly directed projection which is at some distance from the hook and which is located between the bridge element and the holder in the locked position.

To secure the cap all that is required is to press the spring towards the casing. As this is done, the spring guided in the guide track automatically snaps into the holder since the projection on each of the limbs of the spring is pressed inwards by the spring element so that the hook at each of the free ends is not engaged until the projection is released from the bridge element and the hooks latch behind the stop faces. I

To effect release it suffices to press the limbs of the spring inward to a slight extent until the projections are located within the space covered by the inside crosssection of the bridge element. At this moment, the spring tension in the central web ensures that the limbs are pulled a little distance away from the casing. The

books are thus removed from the latching position, and

the cap can be withdrawn.

For the purpose of fitting and releasing the fixing spring, it is only necessary for the space disposed radially outwards of the cap to .be accessible, since whenthe spring is being fitted it only needs to be pushed towards-the casing, and it is not even necessary to use a tool for this. Also, the release of the spring can be achieved by for example pushing the flat tip of a screwdriver between the bridge element and a limb of the spring and then turning the screw-driver slightly about its longitudinal axis. The limb of the spring can of course also be engaged at some other point and pressed inwards.

Particular advantage accrues if each projection is at a distance from the hook that is greater than the width of the bridge element. Thus, when the hook reaches the bridge element the projection can have already moved out of the bridge element again. The result of this is that the hook moves outwards, and the curved spring is prevented from falling out of the cap. The fixing element cannot therefore get lost.

It is also advantageous if the limbs of the spring each embody an angled portion, between the projection and the central web, that bears against the side wall of the cap. As long as the projection is still located beneath the bridge element when the spring is being pushed on, these angled portions ensure that each hook is not only pressed inwards but is even turned inwardly and can therefore be guided into the latching position in an unrestricted manner. In the latched position, each angled portion forms a solid backing element which increases the expanding force for effecting latching, since the spring arm between the hook and the backing element is shorter than the limb of the spring as a whole.

In a preferred embodiment, the inner wall of the bridge element extends obliquely inwards towards the open side of the cap. In this way, a gradual increase in friction is achieved so that the greatest force can be applied only just before the latching position is reached.

Also, the guide track may extend obliquely outwards in the direction of the openside between the base of the cap and the bridge element. This again leads to a gradual increase in friction. When the spring is fitted for the first time, the books can easily pass over this inclined face. Finally, when the spring is released, the angled portions of its limbs are guided inwards along these inclined faces into the position in which the spring is relieved of tension, so that the movement of the spring away from the casing is aided.

In particular, the spring is made of steel strip. Steel strip can be readily bent into the required shape, and.

the required resilience can be readily obtained by a suitable choice of cross-section of strip.

The invention will not be described in more detail by reference to an embodiment illustrated in the drawing, in which:

FIG. lshows the connecting device of the invention in the assembled condition,

FIG. 2 is a cross-section through the connecting device at the level at which the fixing spring is positioned, the spring being seen in its outer position,

FIG. 3 is a simplifed illustration corresponding to FIG. 2, but with the spring aboutto move into the latching position, and

FIG. 4 provides a similar illustration to that of FIG. 3, but with the spring located in the latching position.

through in such manner that they are insulated therefrom. Mounted on the guide pins is a plug element 5 which is illustrated in broken lines in FIG. 2; the plug element, apart from embodying terminals for connecting the external supply lead, may alsoincorporate a starting relay and an excess temperature protective cutout. Also secured to the casing is a holder 6 which comprises stop faces 8 provided on each of two bent-up tabs 7. A terminal 9 for the earth wire is also provided on the holder.

The plug element 5 is covered by a cap 10 which is urged by means of a U-shaped spring 11 of strip material towards a bearing face secured to or constituted by the cap. The spring is held in a guide track 12 which is straddled by a bridge element 13.

The spring 11 consists of a central web 14 which has a median bearing face which slopes upwards towards the corners 15. Each limb 16 of the spring incorporates an angled portion 17 whereby it bears against the cap 10, a projection 18 and, at its free end, a hook 19. The inner surface of the bridge element 13 is inwardly inclined towards the open end of the cap 10, and outside the bridge element the surface of the cap is outwardly inclined in a portion 21 towards the open side of the cap. The distance between each projection 18 and each hook 19 is greater than the width of the bridge element.

If it is assumed that the spring 11 occupies the initial position shown in FIG. 2, then if pressure is applied to the central web 14, the angled portions 17 move downwards over the inclined faces 21 on the cap, and the projections 18 over the inclined faces 20 of the bridge 13. As this happens, the lower portion of each limb 16 together with each hook 19 is swung inwards (see FIG. 3). Each hook 19 moves downwards in an unrestricted manner into the gaps between the cap 10 and the tabs 7. As soon as the projections 18 pass clear of the bridge element 13, the lower portion of each limb 16 springs outwards, the hooks 19 engaging behind the stop faces 8 of the holder 6. The cap 10 is then pressed firmly against the abutment surface 12 by the spring force of the central web 14. This method of attachment is completely vibration-proof.

In order to release the spring, the lower portion of each limb 16 is pressed inwards. This can be done by engaging a tool between the bridge element 13 and the tabs 7. It is however considerably more effective to introduce a screw-driver into the gap between the bridge element and the wall of the cap and parallel with this wall and to press the lower portion of the limb 16 inwards by rotating the screw-driver about its longitudinal axis. When the projection 18 disengages from the lower edge of the bridge element 13, the entire spring is automatically pushed away from the casing. This happens as a result of the effect of the spring force of the central web 14 on the one hand and of the effect of the inclined surfaces 21 along which the angled portions 17 slide in the upward direction, on the other. Consequently, the spring moves into the position shown in FIG. 3, and the cap can be easily removed. It

is not possible for the spring to get lost since when the projections 18 move up out of the bridge element 13, the books 19 remain hanging from the lower edge of the bridge element.

We claim:

1. An electrical housing assembly for a refrigerating machine which is attachable to the casing wall of the refrigerating machine comprising, a plug element attached to said wall, insulatingmeans between said wall and said plug, a cover surrounding said plug, retainer members extending from said casing on opposite sides of said cover, channel shaped guide members extending from said casing on opposite sides of said cover, said guide members extending outwardly a greater distance than said retainer members, said retainer members and said guide members having hooking edges, a U-sh'aped spring straddling said cover, said spring having leg elements with hooks at their extremities and projections spaced from said hooks, said hooks and said projections being engageable with said hooking edges.

2. An electrical housing assembly according to claim 2 wherein said spring has a central transversely extending section, each of said spring legs having a V-formed section between said central section and said projection thereof.

Claims

1. An electrical housing assembly for a refrigerating machine which is attachable to the casing wall of the refrigerating machine comprising, a plug element attached to said wall, insulating means between said wall and said plug, a cover surrounding said plug, retainer members extending from said casing on opposite sides of said cover, channel shaped guide members extending from said casing on opposite sides of said cover, said guide members extending outwardly a greater distance than said retainer members, said retainer members and said guide members having hooking edges, a U-shaped spring straddling said cover, said spring having leg elements with hooks at their extremities and projections spaced from said hooks, said hooks and said projections Being engageable with said hooking edges.