US1646038A - Strain relief for the terminal connections of electrical devices - Google Patents

Description

' 9 7 1927' w. w. MILLER 646 038 I smmz RELIEF F'OR'THE TERMINAL commcnous OF ELECTRICAL mmcss Filed June 29, 1922 IN VEN TOR.

ATTORNEY Patented Oct. 18, 1927.

UNITED STATES.

A NT OFFICE:

WILLIAM W. MILLER, OF NEW YORK, N. Y., ASSIGNOR TO THE CUTLER-.I-IAMMER 00.; OF MILWAUKEE, WISCONSIN, ACORPQRATION OF WISGONSIN.

. STRAIN. RELIEF FOR THE TERMINAL CONNECTIONS or ELECTRICAL DEVICES.

Application med June 29, 1922. Serial No. 571,651.

" for equalization ofthe strains on the terminal connections and which insures against short circuiting thereof.

Various other objects and advantages of p the invention will hereinafter appear.

The accompanying drawing illustrates an embodiment of the invention which will now be described, it being understood that the embodiment illustrated is susceptible of modification without departing from the scope of the appended claims.

In the drawing Figure 1 is a longitudinal sectional view 5 of a heater unit having-strain relieving means embodying the invention associated therewith.

Fig. 2 is a sectional view on line 2-2 of Fig. 1; and

Fig. 3 is an end view of the unit shown in Fig. 1.

The of the immersion type and comprises a U- shaped heater element 1 said element including an insulated resistance wire enclosed within a tubular casing 2 and provided with terminal devices 3 and 4. Casing 2 fits within openings in a plug member 5, the same being held within said openings by soldered joints 6. Plug member 5 is provided with a threaded portion 7 on the exterior thereof to be screwed into a threaded opening in a receptacle-or other device and the same fits within a cover member 9 secured thereto by screws 10. Cover 9 is provided with an insulating lining 11 and. the end wall thereof is perforated to receive a shouldered insulating bushing 12. Bushing 12 is held within cover member 9 by a cap 13 riveted to the end wall of said member and said bushing projects inwardly beyond the end wall of lining 11. r

The strain relieving means nal wires of the aforedescribed heater unit includes annular insulating washers 14 and heater unit shown in the drawing is.

for the termi- 15 I preferably ofiresilient materialqthe former beingadapted to abutthe end face of bushing 12 andthe latter being arranged 7 between the former and terminal devices 3 and 4. The opening in washer 14 is of sufficientdiameter to accommodate .terminal wires-16 and for a purpose hereinafter set forth, said wash'er projects outwardly beyond bushing 12 while the opening in washer 15 is of larger diameterthanithe opening in washer 14.

In connecting the heater unit to the terminal wires 16, cover 9 is detached from plug member 5 and the same together -with' washer 14 is "slipped over said wires. The ends of the terminal wires are then passed through the opening in'washer 15 and after looping the same'around the outer edge of said washer and returning the same through said opening connection is made with terminal devices 3 and 4. The loops in the terminal wires are then arranged on opposite sides of the washer 15 and said washer is adjusted so that upon replacement of cover 9 washer 14 will abut the end of bushing 12, to maintain a slight amount of slack in that portionof the terminal wires leading to terminal devices 3 and 4. A r 7 From the foregoing it is apparent that outward strain on the terminal wires 16 clamps the looped portions between washers l4 and 15 and prevents slippage of said portions around washer 15. Further it should be noted that washer 15 is adapted to yield under strains imposed thereon by the looped portionsof terminals 16 and upon inequality in the strains on the terminal wires the same is adapted to be distorted to equalize such strains. It is apparent that the aforedescribed strain relieving means is not limited to electrical devices of the character described and if desired the same can be employed in connection with electrical devices having three or more terminals.

What I claim as new and desire to secure by Letters Patent is:

1. The combination with an electrical device including a base having. spaced terminal devices thereon, a cover for said terminal devices, terminal wires passing through an opening in said cover and connected to said terminal devices and strain relieving means within saidcover including a plurality of washers through which said wires'extend I one of said washers having said terminal wires looped around the same and another of said washers being interposed between 'the looped portions of said wires and said cover.

2. The Combination with an electrical de vice including a base having spaced terminal 7 thereon and being adapted to yield under such strains.

3. The combination with an electrical device including a base having spaced. terminals thereon, a cover fixed to said base and enclosing said terminal devices, terminal wires connected to said devices and passing through an opening in'said cover, an insulating bushing within the opening in said cover and-strain relieving means for said terminal wires including a plurality of perforated washers through which said wires extend one of said washers having said termi nal Wires looped around the same at substantially diametrically opposed points and the other of said washers beingarranged between the looped portions of said terminal said wires extend, said wires being looped around one of saidmembers to provide a clamping action against the other of said members'in'the event ofa pull. on either or both ofsaid wires.

' 5. 'A strain relieffor conductor terminals comprising a base having spaced terminal devices thereon, terminal wires connected to said devices, a cover having an Opening thereinfor receiving said terminal wires, a pair of insulating members su ported by said wires, means on said cover or limiting the outward movement of one of said members, said wires being passed through and looped around the other of said members to provide a clamping action between said members upon an outward pull on said w res. V a

In witness whereof, I have hereunto subscribed my name.

WILLIAM MILLER.

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