US2797274A - Tubular switch - Google Patents

Description

June 25, 1957 I E. M. GREER v TUBULAR SWITCH I Filed Dec. 22, 1953 I *9 a iff a INVENTOR.

ATTORNEYS United States Patent i TUBULAR SWITCH Edward M. Greer, Great Neck, N. Y., assignor to Greer Hydraulics, Inc., a corporation of New York Application December 22, 1953, Serial No. 399,695

1 Claim. (Cl. zoo-61.52

This invention relates to the art of switches, more particularly of the type which operates automatically when at a predetermined position.

It is among the objects of the invention to provide a switch that will automatically and dependably be actuated only when in a predetermined position, that is neat, compact, sturdy, light in weight, easy to mount and may readily be fabricated at low cost from relatively inexpensive materials, which is substantially unafiected by moisture, dust or dirt, which is devoid of delicate springs, levers or fragile contacts and has but few moving parts which are not likely to become deranged, which is not likely to operate prematurely, and which may operate under extreme temperature conditions without affecting its efli-ciency and is not likely to be injured by vibration, shock or impact.

According to the invention, these objects are accomplished by the arrangement and combination of elements hereinafter described and particularly recited in the claims.

In the accompanying drawings in which is shown one or more of various possible embodiments of the several features of the invention,

Fig. l is a diagrammatic view illustrating one application of the switch,

Fig. 2 is a view similar to Fig. 1 of the switch in position for actuation,

Fig. 3 is a bottom plan view of the switch,

Fig. 4 is a longitudinal sectional view taken along line 44 of Fig. 3,

Fig. 5 is a transverse sectional view taken along line 5-5 of Fig. 4.

Referring now to the drawings, the switch 8 desirably comprises a substantially L-shaped tubular member of conducting material such as brass preferably cylindrical in cross section having an elongated leg 10 and a relatively short leg 11 which is desirably closed by a plug 12. The leg 11 extends laterally outward from leg 10 preferably at an angle of slightly greater than 90 degrees, in the illustrative embodiment, such angle being in the order of 93 degrees as at 13.

The free end 14 of the elongated leg 10 is desirably cut away as at 15 and a substantially rectangular metal housing 16 is affixed to said cut away portion as by welding as at 17. Positioned in said housing 16 is a contact member 17 which may be a flexible leaf of suitable conductive metal, preferably substantially U-shaped as shown. To mount the contact member 17, as is clearly shown in Fig. 4, the inner end wall 18 of the housing desirably has an opening 19 in which is positioned the stem of an insulating washer 21. A screw 22 extends through said washer, through an insulating plate 23 positioned on the inner surface of end wall 1 8 and through the cross piece 24 of contact member 17, a nut 25 affixed to the protruding end of the screw securely clamping the contact member 17 and the insulating plate 23 against end wall 18.

The open mouth of the housing 16 is desirably closed by a substantially rectangular plate 26 of insulating maice terial, one end of which rests on the leg 27 of the contact member 17 and the other end of which rests on a ledge 28 of metal mounted on the end wall 29 of the housing, said leg and said ledge extending toward each other parallel to the elongated leg 10. The plate 26 is securely retained in position by means of screws 30 which extend through aligned openings in the plate 26 and the ledge 28 and leg 27 respectively, the screw 30 extending through leg 27 desirably having a nut 32 on its free end.

The leg 34 of the contact member 17 is desirably of greater length than the leg 27 and is inclined downwardly from its cross piece 24 as shown in Fig. 4. When the leg 34 and the wall of the tubular switch 8 are electrically connected, a circuit will be completed inthe manner to be described. To connect the leg 34 and the wall of the tubular switch 8, circuit closing means are provided which move along the length of said tubular switch.

In the illustrative embodiment, the circuit closing means is a metal ball and although but a single ball could serve to close the circuit, two balls 31a and 31b are preferred and are normally positioned in longitudinal alignment in the shorter leg 11 when the leg 10 of the tubular switch 8 is in inclined position as shown in Fig. 1.

Although the switch just described may be used for many purposes, in order that its function may be clearly understood, one application thereof will now be described, it being understood that such application is merely for the purposes of illustration.

In the illustrative application shown in Figs. 1 and 2 the switch is used to control the pouring cycle from a vat 33 of liquid. As shown, the vat 33 has a pouring spout 34' at its upper edge for example and is pivotally mounted on supporting arms 35. The vat which normally is in horizontal position, is connected through a suitable linkage 36 to an actuating means, illustratively a conventional hydraulic jack 37 supplied with fluid through inlet port 38 by means of a pressure line 39 connected through a normally open solenoid operated valve 40 and a manually operated valve 41 to a suitable source of liquid under pressure.

The switch 8 is desirably positioned on the side wall 42 of the vat in such manner that when the vat has been tilted to the position desired for pouring, the elongated leg 10 of the switch 8 will be in substantially vertical position as shown in Fig. 2. The screw 30 extending through ledge28 hence electrically connected to the wall of the tubular switch 8, is desirably connected by lead 43 to one side of a source of electric power. The other screw 31 connected to contact member 17 is connected by lead 44 to one of the terminals 45 of the solenoid operated valve 41 and the other terminal 46 of said valve 41 is connected by lead 47 to the other side of the source of power.

When the vat is in the normal horizontal position, shown in Fig. 1, and the balls 31a and 31b are resting in the short leg 11 of the tubular switch 8, there will be anopen circuit from the power supply to the solenoid operated valve 40 and the latter will remain open.

In the operation of the unit, when it is desired to tilt the vat 33 for pouring, the valve 41 controlling the flow of fluid into line 39 is opened. As a result, fluid will flow through the normally open solenoid operated valve 40 into the hydraulic jack 37 to move the piston (not shown) therein to the right, thereby tilting the vat. When the vat has tilted so that the elongated leg 10 of the switch has been moved to substantially vertical position, the ball 31a being closer to the junction between legs 10 and 11, Will first fall down the elongated leg 10 and wedge between leg 34 of contact member 17 and the adjacent surface of leg 10. Consequently, the contact screws 30 will be electrically connected to complete a circuit from the power source to the solenoid operated valve 40 to close the latter, thereby stopping further flow of fluid under pressure to the hydraulic jack 37 so that the vat will remain in the desired position 'to'p'ourits contents into reservoir R.

Immediately after ball 31a drops down leg 10, -the second ball 31b willroll along leg and then 'also'drop down leg 10, striking against theball 31a further'to'wedge the latter into position between the resilient leg 34 of contact member 17 and the surface'of leg 'ltlto'provide a dependable'electrical contact.

With the switch above described, there 'is-"assurance that a circuit will be closed only when the elongated leg 10'is slightly inclined 'from the vertical sufliciently'so'that the balls in the shorter leg 11 may roll down and fall into the leg 10. As the switch contains-no springs, levers or fragile contacts, it-is not likely to-become-outof order even under extreme conditions of vibration, impactor shock and will dependably complete a desired circuit when at-a predetermined'position.

As many changes could be made in'the above construction, and many apparently widely different-embodiments of this invention could be made without departing from the scope of the claims, it is intended-that'all matter contained in the aboveidescription or shown in thea'ccompanying drawings shallbeinterpreted as illustrative :and-

not in a limiting sense. 1

Having thus .described my invention, what I claimas new and desire to secure by Letters Patent of the United States-is:

said electrically conductive portion being aligned with said housing, a substantially U-shaped contact member positioned in said housing, means atfixing the cross piece of saidcontact member to one of the end walls of the housing, said contact member and said afiixing means being insulated from .said end wall, one leg of said U-shaped member defining, a contact spaced from the electrically conductive portion of said elongated leg, an insulating plate aflixed to the other leg of said U-shaped contact member to close the mouth of said housing, and circuit closing meansinsaid tubular member adapted to move from said short'leg toward the free end of the elongatedleg'to engage both said contact and'said electrically conductive portion to complete a circuit therebetween.

References Cited in I the vfile ,of this patent UNITED STATES PATENTS 1,611,219 ,Minninger Dec. 21, 1926 1219742 Adams 'July 2, 1929 1,761,681 Reis et al. June 3, 1930 1,837,533 Colvin Dec. 22, 1931 2,253,957 Kammerdiner Aug. 26, 1941

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