US2287988A - Fusible strut for automatic sprinklers - Google Patents

Description

June 30, 1942. w. B. GRIIFFITH 2,287,983

FUSIBLE STRUT FOR AUTOMATIC SPRINKLERS Filed July 26, 1940 Patented June 30, 1942 FUSIBLE STRUT FOR. AUTOMATIC SPRINKLEB S William 13.. Grifiith, Audubon' N. J. Application July-26, 1940, Serial No. 347.657

5 Claims. (01.1 169-j-38) This invention relates to improvements in fusible struts used in connection with sprinklers for sprinkler systems for fire protection.

The object of my invention is to construct a strut comprising two members mounted in axial alignment for giving them rigidity against lateral strains and also for permitting free axial movement. I

A further object is to provide a strut comprisin telescoping members, and a fusible element for holding said members in extended relation, and arrange said element for separating the exposed adjacent surfaces of said members sufiiciently to prevent them from permanently uniting due to corrosion.

A further object is to provide a washer formed of fusible material; said washer having a thick central portion and a relatively-thin peripheral portion, arranged so that said thick portion will withstand the compression strains applied to said members, and to provide the members with recesses which are occupied by said thickportion of the washer.

A further object is to construct said members with walls defining said recesses and arrange the walls for compressing the thick central portion of the washer toward the axis of the strut members and thereby reducing the tendency of the material to extrude from between said members when they are held under compression.

These together with variousother-novel features of construction and arrangement of the parts, which will be more fully hereinafter described and claimed, constitute my invention.

Referring to the accompanying drawing:

Fig. 1 is a vertical sectional view of an automatic sprinkler embodying my novel strut.

Fig. 2 is a central longitudinal section of a strut detached, showing a modification of my invention.

In the drawing in which like reference characters refer to like parts, 5 represents a sprinkler of the type disclosed in Letters Patent No. 2,165,477, issued to me July 11, 1939.

The sprinkler 5 comprises a body 6 having a screw thread 1 for connecting the sprinkler with a distributing pipe of a sprinkler system, not shown in the drawing. The body 6 has an outlet passage which is closed by valve 10. A frame l2 upon the body carries an adjustable abutment l3. Separable struts l5 and I6 normally hold the valve l closed. The strut l consists of a split ring mounted on the valve In. The strut I6 is in the form of a lever having abearing head I1 pivotally mounted upon the adjacent ends of 55 33 extends into and fills said recess 30.

the split ring l5 and engaged-by the screw [3 whichtends to swing the opposite end of the strut into engagement with the side face of the ring for holding the valve closed. In the. event of a fire-the strut l6 will swing through the ring l5 and said struts will fall from the frame l2 and allow the valve- [0 to open in the usual manner.

The novel strut lficomprisestwo members [8 and I9 telescopicallymounted; The member 18 is in the form of a cylinder, or rod; having'an axial bore 20, open-at the end oppositeto the bearing head IL The open end of the bore is surrounded by an annular flange 2|.

The member I!) of the strut l6 comprises a shaft 23 having a sliding fit in said bore 20. A flange 24 is formed upon the outer end of-the shaft 23 and isadapted to abut against the flange 2| whenthe-shaft is moved into said 'bore. The member [9': is provided upon its extreme. outer portion with a conical lug, or head25, adapted for engagementwith the lateral face of the ring strut l5. Said member [9 has the shaft portion 23 formed-of sufficient length to provide a rigid bearing between the members [8 and IQ for holding them in alignment when subjected to a lateral thrust, as when forced into engagement with the sideface of thering l 5 by the action of the abutmentscrewfl3. This construction also provides for the free axial movement of said members [8 and 19.

A disk or washer 26, formed of soft solder, or other fusible material, is interposed between the annular 'abutting'fiange surfaces of the members l8 and l9. Said washer 26 is adapted for holding the members l3 and IS in extended relation for locking engagement with the ring I5. When the washer 26 is fused, in the event of fire, the members l8 and I9 will telescope sufficiently to allow the strut Hi to swing through the ring 15. The washer 26 has an axial aperture through which the shaft l9 extends, and the outer diameter of the washer corresponds to the diameter of the flanges 2| and 24.

Figs. 1 and 2 illustrate forms of my invention constructed forfurther reducing the tendency of the fusible material of the washer to extrude from between the members of the strut.

The strut member [8, shown in Fig. 2, is provided with an axial recess or counterbore 30, which is defined by a conical wall 3|.

F g. 2 shows a fusible washer 32 hav ng an axial protuberance 33 which gives thecentral portion of the washer a relatively thicker body than the periphery of the washer. Said protuberance The thicker body portion 33 of the washer is confined within said recess 30 by the Walls 3| which are inclined in a direction for compressing the body portion of the washer toward the axis of the strut. By this construction the thick axial portion of the washer presents a greater resistance to a force tending to move the flanges 35 and 36 into abutting engagement and reduces the tendency of the material of the exposed annular portion of the washer from extruding between the spaced flanges 35 and 36.

The resistance of the washer 32 against compression is further increased by providing the flanged head 38 of the member I9 with a recess 40, which is similar in construction to the recess 30 formed in the member 18. The washer 32 is also provided with a second protuberance 4| adapted to enter and fill the recess 48.

Fig. 1 shows a construction of the members 18 and [9 in which the axial recesses 44 and 45 are formed by cylindrical walls 46 and annular bottom Walls 41, forming a series of recesses of different depths arranged in step formation and adapted for confining the fusible material, of whichthe washer 26 is formed, from extruding from the members of the strut. The Washer 23 is provided with enlarged axial portions 5! and 52, adapted to occupy the recesses 44 and 45 and take the compression to which the strut members are subjected.

The operation of the device is as follows: The members l8 and 19 of my novel strut are held in extended position for locking engagement with the ring strut l5, by the fusible washer, which has a thickness in excess of the distance the members l8 and I9 must be contracted to pass through the ring [5. When the material forming the washer is fused it flows from the members l8 and I9 and allows the shaft 23 to be moved into the bore of the member l8, so that the strut l6 will swing through the ring and release the valve l0.

The failure of struts to operate due to corrosion, is eliminated by the washer forming a'seal for excluding the atmosphere from the sliding surfaces of the shaft l9 and the bore of the cylinder l8. The periphery of the Washer has sulficient thickness to prevent corrosion between the exposed metal surfaces of the adjacent flanges of the members 18 and I9.

The washers 26 and 32 shown in Figs. 1 and 2, are provided with relatively thicker axial portions adapted for reducing the compression upon the peripheral portions of the washers, so that the soft material of which the washers are formed will not extrude from the strut members at the ordinary temperature. By this construction the washers may be formed of material which will fuse at a low temperature, thus making the strut very sensitive in operation.

I claim:

1. An automatic sprinkler having separable struts, one of said struts comprising telescoping members, annular abutting surfaces upon said members adapted to engage when said members are in contracted relation, a washer formed of fusible material positioned between said surfaces for holding said members in extended relation, said washer having a central portion which is relatively thicker than its peripheral portion, and one of said members having an axial recess formed therein adapted to be occupied by said thicker portion of the washer.

2. A fusible strut comprising a rod having an axial bore, a shaft slidably mounted in said bore, enlarged flanges upon said rod and said shaft adapted to abut when the shaft is moved into said bore, a washer formed of fusible material positioned between said flanges; one of said flanges having axial counterbores extending to different depths therein and arranged in step formation, and an axial protuberance upon said washer adapted to occupy said bores.

3. A fusible strut comprising a rod having an axial bore, a shaft slidably mounted in said bore, an enlarged head upon the outer end of said shaft, a washer formed of fusible material, said washer having a peripheral portion located between the head and the end of the rod, said Washer having an axial portion which is relatively thicker than its peripheral portion, and said rod having an axial counterbore adapted to be occupied by said thicker portion of the washer.

4. A fusible strut comprising arod having an axial bore, a shaft slidably mounted in said bore, an enlarged head upon the outer end of said shaft, a washer formed of fusible material, said washer having a peripheral portion located between the head and the end of the rod, said washer having an axial portion which is relatively thicker than its peripheral portion, and

" said head having a recess surrounding said shaft and adapted to be occupied by said thicker portion of the washer.

5. A fusible strut comprising a rod having an axial bore, a shaft slidably mounted in said bore, an enlarged head upon the outer end of said shaft, a washer formed of fusible material, said washer having a peripheral portion positioned between said head and the end of the'rod, protuberances positioned axially upon opposite faces of the washer, and said rod and said head having axial recesses formed therein adapted to be occupied by said protuberances.

WILLIAM B. GRIFFITH.

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