U.S. patent number 3,725,972 [Application Number 05/178,111] was granted by the patent office on 1973-04-10 for fire link and method of actuating same.
Invention is credited to Francis J. McCabe.
United States Patent |
3,725,972 |
McCabe |
April 10, 1973 |
FIRE LINK AND METHOD OF ACTUATING SAME
Abstract
A releasable link is provided to open under predetermined
conditions; said link having the capacity to be reset under
predetermined temperature conditions. The link includes a
bimetallic element for effecting opening and closing. The link may
also include heating means for actuating the bimetallic element,
and secondary circuit control means for actuating signals or
controlling current to the heating means.
Inventors: |
McCabe; Francis J. (Erwinna,
PA) |
Family
ID: |
22651246 |
Appl.
No.: |
05/178,111 |
Filed: |
September 7, 1971 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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103467 |
Jan 4, 1971 |
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133196 |
Apr 12, 1971 |
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Current U.S.
Class: |
16/48.5; 49/2;
160/1 |
Current CPC
Class: |
F24F
11/00 (20130101); H01H 37/52 (20130101); F16G
15/12 (20130101); F16G 15/04 (20130101); G08B
17/06 (20130101); F24F 11/33 (20180101); F24F
2110/10 (20180101); F24F 11/30 (20180101); Y10T
16/22 (20150115) |
Current International
Class: |
F24F
11/00 (20060101); G08B 17/06 (20060101); F16G
15/04 (20060101); F16G 15/00 (20060101); H01H
37/00 (20060101); H01H 37/52 (20060101); F16G
15/12 (20060101); E05f 015/20 () |
Field of
Search: |
;160/1,2,6,8,5 ;16/48.5
;49/1,2 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Griffin; Donald A.
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of my prior copending
applications, now abandoned, for a LINK, Ser. No. 103,467, filed
Jan. 4, 1971, and a FIRELINK AND METHOD OF ACTUATING SAME, Ser. No.
133,196, filed Apr. 12, 1971, and discloses and claims, in part,
the subject matter disclosed and claimed in those applications.
Claims
I claim:
1. A releasable link having only two elements comprising: a first
element; and a separate heat activated bimetallic second element
not fixedly connected to, but directly engaged with said first
element and coacting therewith to allow said elements to separate
in response to temperature change without changing the state of
either element.
2. The invention of claim 1 wherein a remotely controlled heating
means is connected to said bimetallic element for actuating said
bimetallic element.
3. The invention of claim 2 wherein said heating means comprises an
electric heating element engaging said bimetallic element.
4. The invention of claim 1 wherein a pin is attached to said
bimetallic element and passes through said first element.
5. The invention of claim 4 wherein said bimetallic element is
fixedly connected to a base at one end and said pin is connected to
the free end thereof.
6. The invention of claim 4 wherein said second element includes a
means embracing said first element to confine it.
7. The invention of claim 1 wherein said second element is provided
with means to provide an air passage to the bimetal.
8. The invention of claim 1 wherein said electrical means are
connected to said bimetallic element for heating said element.
9. The invention of claim 8 wherein said electrical means comprises
electrical leads directly connected to said bimetallic element.
10. The invention of claim 8 wherein said electrical means comprise
heating means and a pair of electrical contacts attached to said
link, one of said contacts being connected to said bimetallic
element, whereby as said bimetallic element moves in response to
heat, said contact moves with it.
11. The invention of claim 1 wherein electrical means are provided
attached to said link to signal the release of said elements.
12. The invention of claim 11 wherein said electrical means
comprises a pair of electrical contacts.
13. The invention of claim 12 wherein one of said contacts is
connected to and moves with said bimetallic element.
14. In a method of actuating a fire link to release the link
elements from their engaged condition, the improvement comprising:
electrically heating said link to control the engagement of said
link elements without changing the state of the link.
15. In the method of claim 14 applied to a link having a bimetallic
element to control the engagement of said link elements, the
improvement comprising: remotely supplying electrical current
directly to said bimetallic element to heat said element to control
said engagement.
16. The invention of claim 15, wherein said current is continuously
supplied to said bimetallic element to retain said link elements in
their engaged condition.
17. In the method of claim 15 automatically controlling the current
supplied in response to the position of the bimetallic element.
18. In the method of claim 14 automatically electrically signalling
the release of said elements.
Description
BACKGROUND OF THE INVENTION
This invention related to links for use in automatically actuated
equipment forming a part of a fire-fighting system, and more
particularly, to a fire link for use with devices such as fire
dampers in air ducts.
In the prior art, such links were generally made of two pieces of
metal fused together with solder; the solder being the means for
releasing the link when the ambient temperature rose above a
certain level; for example, 160.degree. F. Such links are shown in
use with fire dampers in my prior U.S. Pat. Nos. 3,273,632 and
3,401,734. It will be observed in these patents that the melting or
change of state of the solder permits the link to be opened by the
fire damper to close off the air duct.
It is also known to provide a means for melting the solder by
remote control.
In practice it is difficult to make these links accurately, since
it is particularly difficult to control the amount of solder and
the solder distribution on the links. Further, as a practical
matter the links are not resettable.
It is desirable to provide a link which is capable of being
manufactured so that it opens or releases at a predetermined
temperature. It is further desirable to have such a link which can
be reset and which can be remotely operated.
SUMMARY OF THE INVENTION
My invention provides a mechanically operable resettable link
capable of highly accurate predetermined control as to opening and
closing; which does not undergo a change of state in order to
function. The link also provides a means whereby remote control can
be used to actuate the link. The link comprises two parts
interconnected by a pin. When the pin is withdrawn, the parts can
be separated. A means is provided for withdrawing the pin; said
means being a bimetallic element upon which the pin is mounted.
Further means are provided in alternate embodiments of the
invention for heating the bimetallic element by remote means and
for automatically signalling and controlling the heat to the
element.
Accordingly, it is an object of my invention to provide a new and
novel fire link which can be simply and accurately
manufactured.
Another object of my invention is to provide such a link which does
not undergo a change of state and which can be reset.
A further object is to provide such a link which can be remotely
controlled.
A further object is to provide a link with means to control
secondary circuitry for signalling or controlling the action of the
link.
These and other objects of my invention will become apparent from
the following description with reference to the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a fire link in accordance with one
embodiment of the present invention;
FIG. 2 is a top view of the link shown in FIG. 1;
FIG. 3 is a view taken as indicated by the lines and arrows e--3 in
FIG. 2;
FIG. 4 is a view of another embodiment of my invention, similar to
FIG. 3; and
FIG. 5 is a view of another embodiment of my invention, similar to
FIG. 3 with the parts reoriented.
The figures include positive and negative signs to indicate
electrical potential.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Although specific forms of the invention have been selected for
illustration in the drawings, and the following description is
drawn in specific terms for the purpose of describing these forms
of the invention, this description is not intended to limit the
scope of the invention which is defined in the appended claims.
In FIG. 1 a link is shown in accordance with one embodiment of the
present invention wherein a remote control device is utilized with
the link to accuate the link and open it. This remote control
device comprises an electrically operated heating element. To
understand the nature of this heating element and its function with
the basic link construction in accordance with the preferred
embodiment of the present invention, I will first describe the link
and its function without the use of this electrical heating
element.
The basic link comprises two elements which are pin connected
together. The first link element 10 is a substantially flat,
rectangular metal strip having joined thereto in any suitable
manner a number of other metal strips and including at one end a
hole 12 providing a ready means for attachment to a wire or chain
in a fire damper or the like.
The second link element 14 is also a substantially rectangular flat
metal strip with a hole 16 at one end also providing a means for
ready attachment to a wire or chain in a fire damper or the like.
The elements are normally held together by pin 18 which passes
through a clearance hole 20 in element 10 and a clearance hole 22
in element 14.
A flange 24 is provided on the element 10. The flange is made of a
flat strip of metal which has been bent intermediate the ends
thereof so that when one portion is held flat against the underside
of element 10 and is welded thereto, the remainder extends
outwardly away from and then parallel to the element 10. Thus,
there is formed an envelope or enclosure confining the element 14;
both while the pin 18 is in the position shown in FIG. 3, and while
it is being withdrawn.
The pin 18 passes through the clearance hole 26 in element 24. The
pin is connected by means of a swaged rivet 28 to a bimetallic
element 30. The bimetallic element is made of two flat strips of
dissimilar metals adhered together in any well known manner.
Bimetallic elements are commonly used in thermostats and the like.
The strips of metal forming the bimetallic element 30 are attached
at one end to the element 10 as by means of the rivets 32. The
bimetallic element is similar in form to the element 24 so that it
extends outwardly from the point of engagement at 32 to a point
clearing the element 24, at which point it extends parallel to the
element 10.
What has been described thus far is the basic link in accordance
with this invention, although it will be apparent from this
disclosure that changes could be made within the principle of the
invention. In operation the bimetallic element is arranged so that
in normal ambient temperatures it is in the position shown in FIG.
3 with respect to the element 10 and the element 14. In this
position the link is connected or closed, and if the ends of the
members 10 and 14 were connected to a wire or a chain in a fire
damper the forces on the link would be in the direction of the
arrows shown in FIG. 3. The link would be in position to retain the
blades of the fire damper in an open condition so that air could
flow through the damper.
In the event of a fire, the hot air would rise and rush through air
ducts and through the damper and when this hot air came in contact
with the bimetallic element 30 the differences in the coefficients
of expansion of the metals in the bimetallic element would cause
its free end 34 to move away from the free end 36 of the element
10. As it did so, it would withdraw the pin 18 from the hole 20 and
hole 22 and as the pin was completely withdrawn from the hole 22
the elements 10 and 14 would separate from one another under the
action of the forces from, say, the weight of the damper
blades.
Note that the action of the link is purely mechanical and it does
not undergo any change of state. Therefore, in the event that the
link is not damaged in whatever fire caused the temperature to
rise, the link can be reset at normal temperatures. The bimetallic
element returns to the position shown in FIG. 3 at normal
temperatures.
The large oval hole 38 in the element 10 provides a means for
allowing the heated air to flow through and come into contact with
bimetallic element 30, thereby increasing the efficiency of the
device.
In an alternate embodiment of this invention, a means is provided
for remotely controlling the action of the bimetallic element. This
means comprises an electrical heating element which, in its
preferred embodiment, comprises nichrome wire 40, which is adhered
by any suitable means, such as adhesive to the inner surface of the
bimetallic element 30. The positive and negative electrical leads
indicated on the drawings provide a means to establish current flow
through the nichrome wire from any suitable controlled electrical
source (not shown) to heat the wire and the bimetallic element.
Thus, it is possible to energize the nichrome wire and provide heat
to the link to open it in the manner previously described and allow
the fire damper, or whatever device was being controlled by the
link, to become operative. It will be understood that various
changes in the details, materials, and arrangements of parts which
have been herein described and illustrated in order to explain the
nature of this invention, may be made by those skilled in the art
within the principle and scope of the invention as expressed in the
claims. For example, a portion of the bimetallic element itself can
be the heating means.
In the embodiment shown in FIG. 4, the electrical leads are
directly connected to the bimetallic element 130. Since the element
will carry current, it is insulated at its point of connection to
element 110 as well as at the pin 118. This electrical insulation
is provided by washers 150, 151, 152 and 153, and by bushings 154
and 155. In this manner, the bimetallic element 130 can be heated
directly from a remote source to open the link.
Alternatively, in either of the electrically operated embodiments,
the metals in the bimetallic element can be reversed so that it
must be constantly heated in order to remain closed. If the circuit
is opened and the electrical power cut off, then the link would
open automatically.
Mechanical details can also be changed within the scope of this
invention, such as by providing a hook 112 at the end of the
element 110 in lieu of the hole 12 FIG. 1 and/or a double ended
hook 116 in lieu of the element 14, FIG. 1.
In FIG. 5 a further embodiment of my invention is shown in an open
condition, that is, wherein the bimetallic element has withdrawn
the pin from the envelope created by the flange 24 and the main
body 210 of one element of the link thereby allowing the other
element of the link to be separated by the opposed forces (shown by
arrows in FIG. 3). This embodiment is provided with means for
controlling a secondary circuit for purposes of signaling in the
event that the link is opened or for purposes of controlling the
amount of heat supplied to the bimetallic element in order to
prevent it from overheating and being destroyed. This secondary
circuit control means comprises two substantially flat narrow gage
flexible metallic elements which are normally bent so that they are
in contact when the device is in the closed position with the pin
218 fully inserted through the holes in the hole member 210. The
elements 280 and 282 each have a small metallic button 284,286
respectively riveted to the adjacent free ends thereof. The other
ends are retained as follows. The end of the element 280 is held in
electrical contact with the electrical take off lug 288 which is
insulated from the main body 210 by the insulator pad 290. On the
other side of the element 280 there is a further insulator pad 291
which insulates these elements from the bimetallic element 230. An
electrical lug 292 is in electrical contact with the bimetallic
element 230 and an insulator pad 293 separates this lug from a
metallic retainer pad 294. All of these pads and parts are held
together by a plurality of rivets, such as the rivet 295, which
pass through clearance holes in the electrical elements and are
rolled over to retain the elements in a firm fixed position. The
pin 218 is electrically insulated by a washer 219 from element 282
which is in electrical contact with the bimetallic element 230. A
further insulator washer 221 is provided between the retainer
washer 223 and the rolled head of the pin 218 so that these parts
are likewise held in a firm fixed position and are electrically
insulated as shown.
When the bimetallic element is heated and is moving from a fully
closed position to the position shown in FIG. 5, the buttons 284,
286 will remain in contact for a predetermined distance. In the
event that it is desired to signal the opening of the link, the
elements 280, 232 can be bent before hand to an extent necessary
such that when the pin moves to the position shown in FIG. 5 the
buttons will separate as shown and break a circuit. A circuit, such
as a low voltage secondary signal circuit can easily be provided
from the lugs 288, 292 and secondary instrumentation or signal
controls can be actuated by merely braking this circuit. These are
not shown in further detail, since such circuits are well
known.
Alternatively, if it is desired to heat the bimetallic element 230
through circuitry connected to these lugs, the separation of the
buttons at a predetermined point will prevent overheating by
breaking the circuit. However, the link will be maintained in the
opened position as long as the circuit remains closed and as the
bimetallic element 230 cools the buttons 284, 286 will come
together and close the circuit again thereby reheating the
link.
It will further be understood that the "Abstract of the Disclosure"
set forth above is intended to provide a non-legal technical
statement of the contents of the disclosure in compliance with the
Rules of Practice of the U.S. Patent Office, and is not intended to
limit the scope of the invention described and claimed herein.
* * * * *