US3474392A - Terminal-block assemblies and mounting rails therefor - Google Patents

Description

, Oct. 21, @969 A. NORDEN TERMINAL-BLOCK ASSEMBLIES AND MOUNTING RAILS THEREFOR Filed Sept. 5, 19s? United States Patent US. Cl. 339-119 13 Claims ABSTRACT OF THE DISCLOSURE An assembly of terminal blocks on a mounting rail has a number of related features:

(1) The mounting rail has two or more side-by-side angularly related mounting sections extending along the rail adapting the assemblyof terminal blocks to be temporarily or finally secured in any one of two or more attitudes, especially useful in limited-access installations;

(2) Laterally elongated screw slots allow the rail to be held loosely and shifted from one mounting section to another;

(3) A laterally accessible extension of a terminal-block gripping part of the mounting rail provides gripreleasing leverage; and

(4) The angularly related mounting sections contribute resiliency for releasing the grip.

The present invention relates to electrical terminalblock assemblies and to mounting rails for terminal blocks in such assemblies. The present invention in some respects represents improvements to like apparatus disclosed and claimed in my Patents Nos. 3,253,251, issued May 24, 1966, and No. 3,259,876, issued July 5, 1966.

An object of the present invention resides in providing improvements in terminal-block assemblies for improving the accessibility of the wire-receiving portions of the terminal blocks. In achieving this aspect of the invention, the novel terminal block assembly utilizes a mounting rail that may be mounted in various attitudes so as to hold the terminal blocks in one position during wiring, for easy viewing of the wire-receiving portions of the terminal blocks, and to hold the blocks in another installed position thereafter.

A further object of the invention resides in providing improvements in terminal-block assemblies of the type in which the rail interlocks with the terminal blocks, for facilitating removal of the blocks. In achieving this aspect of the invention, the rail is formed as a resilient channel whose walls have parts that interlock with complemental parts of the terminal blocks, especially for gripping retention, the side walls having a tool-engageable formation or a lateral projection or both, operable to flex the channel and release one or more terminal blocks.

The preferred embodiment of both the foregoing aspects of the invention and the modifications which are shown in the accompanying drawings and which are described in detail below utilize a terminal-block supporting rail in the form of a channel having side wall formed to interlock with and retain the terminal blocks. The side walls have lateral projections that are spaced upward from the bottom of the channel and form a support for the terminal blocks. The lateral projections extend outward to positions clear of the terminal blocks, so as to be accessible for application of pressure to flex the channel and thereby release the terminal blocks. In particular, where the channel bottom is divided into multiple angularly related longitudinal sections and one longitudinal section is fixed to a supporting surface, an adjoining angled section of the channel bottom and the wall of the channel remote from the fixed section combine in flexing when the lateral projection is pressed for releasing the terminal blocks. The spacing of the lateral projections upward from the channel bottom provides clearance from a large flat mounting surface to afford the requisite space for downward block-releasing deflection of the lateral projections. The individual mounting sections of the channel are fiat in the embodiments shown in the drawings, but various other formations at the bottom of the rail can be substituted to achieve the angularly related mounting attitudes.

The mounting of the rail on one of its angularly related mounting sections improves visibility of the wire-receiving end portions at one end of each terminal block mounted in a row on the rail. When the wires are to be inserted, the channel is mounted firm enough for the wiring operation with the ends of the terminal blocks tipped up for improved visibility. After wiring, the tilted terminal blocks can be shifted to their permanent installed condition by shifting the rail to another mounting section.

The shift of the terminal blocks with wires inserted is not restrained by the wires. This is because the wires extend generally parallel to each other toward and transverse to an effective axis about which the whole assembly rocks. The mounting rail inherently shifts laterally and rocks about that axis. As a result, the wires connected to the terminal-blocks are free to shift laterally, they are not required to shift longitudinally, and consequently the wires do not interfere with the change in the attitude of the terminal-block assembly as it is shifted from one mounting section of the channel bottom to another.

The channel constructed to achieve the foregoing results helps in realizing yet another advantage. The mounting rail develops great strength in the sense of a beam supported at its ends. The terminal-block assembly including such a rail can be secured to two spaced-part supports and yet the assembly has its own strength and stiffness to a remarkable extent, without relying on structural support along the length of the terminal-block mounting rail. This beam stiffness of the rail is realized despite the resilience of the channel walls needed for gripping the terminal blocks and for spreading the walls to release that grip.

The nature of the invention and the foregoing and other features and advantages will be better appreciated from the following detailed description of the presently preferred embodiment and modifications shown in the accompanying drawings which form a part of the disclosure of the invention. In the drawings:

FIGURE 1 is a plan view of a novel terminal-block assembly embodying features of the invention, mounted in a tilted attitude, some of the terminal blocks being shown in phantom and parts of the assembly being broken away to indicate considerably greater length;

FIGURE 2 is an end view of the terminal-block assembly in the attitude shown in FIG. 1, but drawn to larger scale;

FIGURE 2A is a modified detail of FIG. 2;

FIGURE 3 is an end view of the terminal-block assembly of FIGS. 1 and 2 drawn to the scale of FIG. 2, but secured upright to its support, portions being shown in dotted lines to illustrate the block-releasing shape of the rail;

FIGURE 4 is an end view of the assembly of FIG. 1 drawn to smaller scale, and shown in a common installation to illustrate certain advantages;

FIGURE 5 is a diagrammatic view of the apparatus lit FIG. 4, showing the terminal-block assembly in phantom and in solid lines to illustrate its relative positions when tilted and when upright relative to its support, and the relative positions of the connected wiring;

FIGURE 6 is an end view of a modified mounting rail for the assembly of FIGS. 1-5 drawn to the scale of FIGS. 2 and 3, showing a part of the rail in dotted lines to illustrate another form of terminal-block releasing rail responsive to stress applied by a tool that is shown in phantom; and

FIGURE 7 is a transverse cross-section of another modified form of mounting rail for the terminal-block assembly of FIGS. 15.

The form of terminal blocks shown in the drawings is shown in my Patents Nos. 3,253,251 and 3,259,876, to which reference may be had for further details. A terminal block suitable for present purposes shown in FIGS. 1, 2 and 4 includes a block of insulation containing at least one connecting conductor 12 and two screw-clamps 14 at the ends, respectively, of each conductor 12. Each screw clamp comprises a clamp 14b of a metal strip bent into the shape of a rectangular frame with overlapping ends at the top through which a screw 14a extends. Screw 14a bears against the top of conductor 12 and, when tightened, draws clamp 14b toward the bottom of conductor 12 to grip an inserted wire W between the bottom wall of clamp 14 and the lower face of conductor 12.

Shown in FIG. 1 are two terminal blocks, each including block 10 and two conductors 12, on a mounting rail 16 of a resilient metal such as extruded alloy aluminum. The mounting rail includes a channel portion having opposed side walls 18a and 18b and a bottom wall divided into two essentially fiat mounting sections 20a and 20b that meet in an obtuse angle of about 165 in an example. Either one of the mounting sections can be selected to be secured by screws 24 to a mounting surface S that is commonly a panel of sheet-metal although it could just as well be two spaced-apart coplanar mounting areas such that the rail 16 forms a bridging structural member supporting the row of terminal blocks. In such an application the considerable beam strength of the rail is an advantage, in that no support for the rail is needed additional to the supporting areas at screws 24 near the ends of the rail.

The side walls 18a and 18b have in-turned edges 26 that interlock with terminal-block retaining formations 28 integral with blocks 10. Legs 30 of blocks 10 rest on lateral projections 32 spaced away from the bottom of the channel and extending outward from side walls 18a and 18b of the channel. There are notches 34 formed in the in-turned edges 26 of the mounting rail, to receive webs 36 at the bottom of block 10, for locating each block 10 on rail 16.

The retaining formations 28 of the terminal block have cam surfaces 28a that engage edges 26 of the rail when a block is being forcefully applied to the rail. The formations 28 are squeezed toward each other (block 10 here being of yieldable molded insulation such as nylon), and the sidewalls 18a and 18b of the channel spread apart resiliently when a terminal block is driven onto a rail to assume the mounted condition shown.

In FIG. 2, mounting section 20b is shown fixed against mounting surface S. In this condition of the rail, the lefthand ends of the terminal blocks slope so as to afford a good view of the wire-receiving portions of the terminal blocks (when seen from above, looking along the arrow in FIG. 2) to recognize whether the clamps 14 are open or not, and to let the user see where a wire is to be inserted. This is of importance in a common form of apparatus in which terminal-block assemblies are used. FIG. 4 is a horizontal cross-section of such apparatus, including a sheet-metal housing having side and front wall portions A and B and a hinged door C. Support S in FIG. 4 typically is a sheet-metal panel of a preassembled circuit unit that includes preassembled wires W; and FIG. 4 shows wires W extending along the corner A-B to the teminal blocks. During assembly of wires W to the terminal blocks, the tilt of the end surfaces of blocks 10 allows a sufficient view of the wire-receiving formations for the installer to see where the wires are to go.

Screws 24 hold the terminal-block assembly securely in place so that each screw clamp 14 can be tightened as needed.

Rails 16 includes a series of screw-receiving openings 36 at spaced-apart points along its length. In this way any suitable length of rail may be cut from a very long extrusion and yet there will be suitable openings 36 available at the ends of the cut length of rail. Openings 36 are provided in each of the mounting sections 20a and 20b, although a single elongated screw opening or slot 36' (FIG. 2A) could be substituted for the two openings shown. ,Screws 24 can be removed after the wiring W is secured (or screws 24 may merely be loosened if slots are used) and the whole assembly can be shifted from the tilted attitude (dotted lines in FIG. 5) to the installed position of FIG. 5 (shown in solid lines) to be held in that position by tightening screws 24. During this shift, the rail moves laterally and it rocks, and the whole assembly swings about axis X toward which wires W extend. As a result of this configuration, wires W do not shift lengthwise. Consequently these wires do not impede the shift of the terminal-block assembly from one position to another in FIG. 5.

Occasion, it may become necessary to remove a terminal block 10. This may be achieved readily by pressing down on one lateral projection 32 (see the arrow, FIG. 5) which extends from the side wall 18b remote from the mounting section 20a in use. Projection 32 extends laterally to a position clear of block 10 so as to provide access for applying pressure. The side wall 18b and the section 20b of the channel bottom combine in yielding to this pressure, to allow spreading of the formations 26 that retain the blocks 10 in place, thus releasing a block 10 from the grip of the rail. The increased leverage gained by utilization of the interposed yieldable portion 20b of the channel botom adds to the effective length of the lateral projection 32 in enforcing the necessary spread of edges 26 without resort to excessive pressure on projection 32. Were section 20b in use for mounting the assembly, then pressure on the other lateral projection 32 would act in like manner to effect release of a terminal block 10.

FIG. 6 shows a modified form of mounting rail 16 having tool-receiving formations 32a, in particular having grooves extending all along rail 16 for receiving a screwdriver. Rail 16' is otherwise the same as rail 16. This modification is of advantage in cases where the metal of the rail is hard to flex by means of simple pressure as in FIG. 3. In FIG. 6, the screwdriver or other tool T is inserted and forcibly tilted outward to deflect the side-wall 18b.

FIG. 7 shows still a further modified form of mounting rail 16" that may be substituted in the assembly of FIGS. 1-5. In FIG. 7 the bottom wall of the channel is divided into three flat sections, including a central section 20a for securing the terminal-block assembly to its support in its upright attitude; and two sloping mounting sections 20b and 20c each with an obtuse angle to section 20a (e.g., make it possible to mount the assembly upright or tilted to either side.

Variations of the foregoing and further modifications will occur to those skilled in the art, and therefore the invention should be broadly construed in accordance with its full spirit and scope.

What is claimed is:

1. A mounting rail for terminal blocks and the like, including a resilient channel portion having confronting side walls upstanding from a bottom wall, said side walls having retaining formations effective when in their normal relationship for interlocking with complemental retaining portions of terminal blocks when mounted thereon, characterized in that at least one of said side walls has a terminal-block releasing formation extending laterally outward relative to said resilient channel portion, providing leverage for deflecting said one wall out of said normal relationship to the other of said walls and into a terminal-block releasing relationship thereto.

2. A mounting rail for terminal blocks in accordance with claim 1 wherein said retaining formations are directed inward relative to said channel portion for gripping engagement with complemental portions of terminal blocks, whereby downward pressure on said laterally outward projecting formation tends to drive one of said retaining formations away from the other for releasing said gripping engagement.

3. A mounting rail for terminal blocks in accordance with claim 1, wherein said bottom wall is divided into at least two longitudinally extending mounting sections meeting at an obtuse angle, whereby when one of said mounting sections remote from said one wall is. secured to a mounting surface, said one wall and one of said mounting sections adjoining said wall act together in providing yielding response to terminal-block releasing pressure applied to said lateral projection.

4. An elongated rail for mounting modular terminal blocks having wire-receiving terminals, said rail having means for retaining terminal blocks when disposed thereon and having multiple mounting formations extending in side-by-side relation along the bottom thereof adapting the rail to securement to a supporting surface selectively in plural positions at different angles about an axis parallel to the rail for improved access to wire-receiving terminals of the terminal blocks.

5. An elongated terminal-block mounting rail in accordance with claim 4, formed as a channel having a bottom wall and opposed side walls, said mounting formations being incorporated into the bottom of the channel and said terminal block retaining means being disposed on the side walls of the channel.

6. An elongated mounting rail in accordance with claim 4, including plural screw-receiving slots distributed along the rail and each of said slots extending transversely of said rail so that the rail can be shifted from one of said angularly related positions to another while being held captive under the heads of loosened screws in certain of said slots, and the rail can then be secured to a supporting surface in any selected one of said positions by tightening the screws.

7. An elongated mounting rail in accordane with claim 4, wherein said mounting formations are fiat longitudinally extending sections including screw-receiving slots extending across multiple adjoining mounting sections, whereby one mounting section may be substituted for another by lateral shifting of the channel while the channel is held captive to a support by screws extending through the slots and with clearance under the heads of the screws.

8. A terminal block assembly comprising an elongated mounting rail and a row of modular terminal blocks thereon, said terminal blocks comprising wire-receiving portions of limited accessibility in some installations, and said mounting rail having multiple angularly related longitudinally extending mounting sections adapted to be selectively secured to a supporting surface, whereby the terminal blocks may be held in place by securing one said mounting section to a supporting surface and thereupon said terminal blocks may be wired with said wirereceiving portions in a relatively accessible attitude and then said assembly may be shifted and another of said mounting sections may be secured to the supporting surface for disposing the terminal-block assembly in a different, installed attitude.

9. A terminal block assembly in accordance with claim 8, further characterized in that said rail is in the form of a channel having side walls and a bottom wall, said side Walls being formed to interlock with complemental portions of the terminal blocks and said bottom wall being divided into said longitudinally extending mounting sections.

10. A terminal-block assembly in accordance with claim 8, wherein said rail is in the form of a channel having side walls formed to interlock with complemental portions of the terminal blocks, further including a lateral projection at least along one of said side walls extending to an accessible position clear of said terminal blocks, whereby pressure may be applied to said lateral projection to flex the channel and thereby release the interlock of the mounting rail with the terminal blocks.

11. A terminal block assembly in accordance with claim 9, further including a lateral projection extending along at least one of said side walls in supporting relation to said terminal blocks and projecting to a position clear of the terminal blocks for application of terminal-block releasing pressure thereto, said lateral projection being spaced from the supporting surface to accommodate deflection of the lateral projection toward the surface on which the channel is supported.

12. A terminal-block assembly comprising an elongated mounting rail and a row of modular terminal blocks thereon, said rail having a resilient channel including opposed side walls formed to interlock with complemental portions of the terminal blocks for holding the terminal blocks on the mounting rail, said channel having a lateral projection extending to an accessible position relatively unobstructed by said terminal blocks and being operable for shifting at least part of one of said side walls relative to a companion part of the other of said side walls to release at least one of said terminal blocks.

13. A terminal-block assembly in accordance with claim 12, wherein said side walls grip a part of each of said terminal blocks, and wherein said lateral projection extends from one of said side walls, whereby said terminal blocks are releasable by pressure against said lateral projection for spreading said side walls.

References Cited UNITED STATES PATENTS 2,903,661 9/1959 Gofistein 248207 X 3,001,748 9/1961 Austin 248-204 X 3,259,876 7/1966 Norden 339198 RICHARD E. MOORE, Primary Examiner US. Cl. X.R. 339-198

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