US 2636955 A
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April 28, 1953 s. A. GEORGE ELECTRICAL SWITCH BOX 2 SHEETS-SHEET 1 Filed Feb. 14, 1951 ATTOR NEYS' STEPHEN AJGEORGE Fl l 5'1 Apnl 28, 1953 s. A. GEORGE 2,636,955
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Patented Apr. 28, 1953 UNITED STATES PATENT OFFICE ELECTRICAL SWITCH BOX Stephen A. George, Johnstown, Pa., assignor to Stephen A. George Company, Johnstown, Pa... a corporation of Pennsylvania Application February 14, 1951, Serial No. 210,961
3 Claims. 1 This invention relates to electrical switch boxes, and moreparticularly toelectric switch boxes of the-type having contacts on thecoveroi,v shock. tothe-person who is removing'and re placing a fuse in the device.
It is a further object of the invention to provide a switch box, the mating contacts of which make a sure-and positive connection.
It is'a further. object of this. invention to provide a'switchbox, the cover whichserves also as the'movable arm of the switch.
It is'a further object of this invention to provide a. switch boxhaving a. hinged cover, the box and the cover cooperating to completelyenclose the parts of the switch and protect it from These and otherobjectscf the invention will beapparcnttothose skilled in the art from a perusal of theiollowing detailed description taken in conjunction with the accompanying drawings wherein:
Figure 1 is a front elevational view oi. a-
presently preferred embodiment of the invention showing the box closed;
on the line 22 of Figure 1 showing the arrangement of parts in theinterior of the device when the cover is closed;
Figure 3; isa, front elevational view of the box with the cover open and revealing the components in the box and on thecover;
Figure 4; is a sectional view of the sametaken approximately on the line. 4.-4 of Figure, 3;
Figure 5 is a viewsimilar to Figure 4 and illus- 45 Figure 2 is a sectionalview taken substantially tratlng an alternate form of spring mounted contact finger;
Figure 6 is a view similar to Figure 2 and fur'- ther illustrating-the alternate form of spring mounted contact finger; and
Figure 7 is an exploded view of the spring mounted contact finger shown in Figures 5 and 6.
Referring now in detail to the drawings, it will be seen that throughout Figures 1 through 6 there is shown a box designated generally by the numeral if), having a rear wall ll, sides I2, a top wall. l3 and a bottom wall l4.
Thewall i I of the box is secured to a mounting plate l5; and the wall l3 of the box is provided with a. perforation and inset grommet bushing I6 through which is trained an electric wire 22.
An insulating block I I is secured to the wall ILinterna-lly'of the box adjacent the upper end l3, through suitable fastening means IS. A sta tionary contact plate is mounted on the in- The sulating block I! by'fastening means 2|. aforementioned wire 22, of the circuit to be interrupted, is, as previously stated, trained through the grommet l6 and at one end is securely connected to the stationary contact plate 20, as shown.
An insulating block is secured to the wall I I of the box adjacent the bottom wall i4 thereof by fastening means 25. Secured to the surface of the insulating block 25 by means of a bracket 33 is one end of a coil spring 28. Spring 28 at its freeend is provided with a contact 30. The
other wire 32 of the circuit to be interrupted hasan end portion thereof trained through an insulating grommet bushing 31 mounted on one side wall I! of the box, and the wire is secured electrically to the mounting bracket 33 holding the spring 28 to the insulating block 25.
For the box I 0 there is provided a cover designated generally by the reference numeral 40. Cover is hingedlyconnected with the wall I4 of box Hi, as indicated generally at 4|. Cover 49 includes'a base member 42, an end member 43 and side membersor flanges 44. The end member-43 is cut away as at to accommodate the grommet bushing [B when the box is inthe fully closed position of Figures 1, 2 and 6.
It will be noted that the side members 44 and end member 43 of cover 40 extend around the sides 12 and end wall l3 of box l0 when the cover is in'closed position. Thus, by this construction In this way, arcs which might occur within the box when the contacts are 46. Secured to the insulating block- 46 at the end thereof near the hinge M is a stationary contact member 50 equipped with a fuse clamp 53. Also secured to the insulating block 46 is a connecting plate 64 to which is rigidly secured a second fuse clamp 69. The fuse clamps 53 and 59 support a conventional removable fuse link 10 as shown.
A salient feature of this invention is the provision of a contact finger carried by the cover 40 for coaction with the contact plate 29 mounted. asbefore described, in the box 50.
-In the form of the invention shown in Figures 1 to 4 inclusive, the mentioned contact finger comprises a single flexible strip 62 which at one end is positively secured to the aforementioned connecting plate'fi i. To the free end of the strip 62 is secured a contact knob 6! of conductive material, such as copper. The knob 6! is shaped to provide a substantially spherical contact surarcing resulting from such engagement and dis-- engagement of knob Bi and plate 29 is reduced to a minimum.
As is believed to be apparent, the flexible strip 62 of contact finger B flexes about its mounted end 63, and to restrain the outward movement of the contact finger without interfering with the desired flexing of the strip 6'2, there is provided a limiting bolt 66 that extends through an opening provided therefor in the strip 62, and is anchored at one end to the insulating block As an alternate to the contact finger fill just described in detail, there may be employed, with even more desirable results, a contact finger of the type detailed in Figure 7, and the application of which is shown in Figures and 6. As shown in Figure 7, this alternate form of contact finger, designated generally by the reference numeral H, comprises a resilient strip 12 and a plurality of relatively thin strips 13, of conductive material providing a laminated strip corresponding substantially to the strip 62 of the aforementioned contact finger cc. Strips 12 and 13 aresecured in superimposed facial contact through the medium of bolts 74 and 15. The strips 12 and 13 are suitably apertured to accommodate the bolts 14,-!5 with bolt 14 additionally functioning to anchor the laminated strips to the connecting plate 64, and the bolt (5 additionally functioning to secure, in the assembly, the contactknob Another salient feature of the contactfinger H is the contact knob 16. This knob i6 is fabricated from carbon and is suitably formed, as is fastening means 41, is a large insulating block- 4 shown, for threaded reception of the bolt I5. The knob 76, also like to the knob Bl, provides a substantially spherical or working contact surface for sliding movement relative to the stationary contact plate 21] incidental to the movement of the knob 16 into and out of electrical contact with the stationary contact plate 20.
It has been found in actual practice that by forming the contact finger H of laminated strips of conductive material, a more desirable tension for the finger is obtained and also better current contact between the finger and the sta tionary contact plate 20 results. Also, by having the knob 76 fabricated from carbon, arcing incident to the engaging and disengaging of knob '16 and plate 28 is wholly eliminated.
In actual use, the switch box will normally be mounted on a wall or other upright surface with the hinge 4! at the lower end of the box as shown in the drawings. It is desirable to mount'the-box it at such a height that it may be reaohed,-and yet be high enough so that it will not be accidentally encountered by a person in the vicinity." It will be further noted that when so mounted the cover 40 swings downwardly to open position.
It will be apparent that when the cover 4D is in the closed position shown in Figures .2 and 6, the spring contact finger (60- or II as the case may be), is in electrical engagement with the stationary contact plate 20, and contact plate 5!] is in electrical engagement with spring biased contact at. To open the box all that is necessary is for the operator, grasping the handle 61, :toexert a pull on the handle whereby the cover 40' is released to swing to open position; As the cover swings to such open position the contact knob (to or H as the case may be), with a slide ing action over the surface of the contact plate 20, moves out of engagement with the latter for interrupting the circuit. With the cover in the open position, access is then readily had to the fuse link H3 for removing or replacing the same as necessary or desired, without the slightest;
danger of electrical shock.
In connection with the foregoing it will be noted that the end of the cover ti! containing the case may be) has made contact with, or broken i Accordingly, any arcing attendant upon operation of the contact with, the contact plate 2%.
switch is eifectively contained" within the box and thereby the operator is completely shielded" from the arcing. In this connection, however, it
may be further noted that by providing the contact finger (81} or H as-the case may be) with al contact knob having a spherical surface in sliding contact with the plate 22!, the possibility of such arcing is reduced to a minimum, and when the contact knob of the finger is fabricated from carbon, as in the case of knob 86, the possibility of such arcing is wholly eliminated.
From the foregoing then it will be seen that an electrical switch box embodying thefeatures of this invention possesses to a material degree salutary high characteristics of safety, ease of operation, and economy of manufacturev andmaintenance.
ofcourse, be understood that such has been done for purposes of illustration and not by way of limitation, and, therefore, only such limitations are to be imposed thereon as may reasonably come within the scope of the appended claims, as for example, it will also be readily appreciated that a resilient contact corresponding to either contact ea or contact H may be substituted for the contact in which event the two contacts carried by the cover ii would then be equipped with a knob having a peripheral surface for sliding movement over the surfaces of the cooperating contacts mounted in the switch box incidental to the movement of the contacts into and out of circuit closing position.
What I claim is:
1. A switch mechanism of the kind described comprising a box, a cover hinged on the box, spaced contacts within the box adjacent the upper and lower ends of the latter, and complemental contacts on the cover of which on consists of a spring arm with a terminal spherical contact foot, the box-carried contact complemental to the last said cover-carried contact being in the form of a plate so that when the cover is opened, the foot both rolls and slides on the plate and leaves the latter at a point remote from that at which it rests when the cover is closed.
2. A switch mechanism of the kind described comprising a box, a cover hinged on the box, spaced contacts within the box adjacent the upper and lower ends of the latter, and complemental contacts on the cover of which one consists of a spring arm with a terminal spherical contact foot, the box-carried contact complemental to the last said cover-carried contact being in the form of a plate so that when the cover is opened, the foot both rolls slides on the plate and leaves the latter at a point remote from that at which it rests when the cover is closed, and an electrical fuse providing electrical continuity between the cover-carried contacts.
3. A switch mechanism of the hind described comprising a box, a cover hinged on the hon, spaced contacts within the box adjacent the upper and lower ends of the and complcmental contacts on the cover of one consists of a spring arm with a terminal spherical contact foot, the boincarried contact complemen tal to the last said cover-carried contact being in the form of a plate so that when the cover is opened, the foot bath rolls and slides on the plate and leaves the later at a point remote from that at which it rests when the cover closed. and the other cover-carried and box-carried contacts consisting of a plate on the one and a spring biased contact on the other provided with a terminal bearing disc bearing on said plate when the cover is closed.
SEPHEN A. GEORGE.
References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 914,677 Scott Mar. 9, 1909 1,896,560 Russel Feb. 7, 1933 2,128,648 Johansson Aug. 30, 1938 2,268,923 Johansson Jan. 6, 1942