U.S. patent number 3,900,795 [Application Number 05/388,520] was granted by the patent office on 1975-08-19 for installation and test tool for ionization smoke detector.
This patent grant is currently assigned to Honeywell Inc.. Invention is credited to Larry D. Larsen, Richard C. Mott, Joseph C. Pekarek, Lee Schuck.
United States Patent |
3,900,795 |
Larsen , et al. |
August 19, 1975 |
Installation and test tool for ionization smoke detector
Abstract
In the present invention a ceiling mounted smoke detector
assembly has a permanently mounted ceiling fixture portion and a
detachably mounted smoke detector head adapted for mounting to the
fixture portion. To provide for ease of installation, removal,
and/or testing of the smoke detector head or of testing the entire
assembly there is an installation and testing tool which
mechanically and electrically interlocks with the smoke detector
head.
Inventors: |
Larsen; Larry D. (Palatine,
IL), Schuck; Lee (Buffalo Grove, IL), Pekarek; Joseph
C. (Mt. Prospect, IL), Mott; Richard C. (Harwood
Heights, IL) |
Assignee: |
Honeywell Inc. (Minneapolis,
MN)
|
Family
ID: |
23534441 |
Appl.
No.: |
05/388,520 |
Filed: |
August 15, 1973 |
Current U.S.
Class: |
324/537; 340/629;
340/628 |
Current CPC
Class: |
G08B
29/145 (20130101); G08B 17/113 (20130101) |
Current International
Class: |
G08B
17/10 (20060101); G08B 17/113 (20060101); G01n
023/12 (); B25b 027/00 () |
Field of
Search: |
;81/3R ;324/158R
;340/237 ;250/388 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Smith; Alfred E.
Assistant Examiner: Hille; Rolf
Attorney, Agent or Firm: Dahle; Omund R.
Claims
The embodiments of the invention in which an exclusive property or
right is claimed are defined as follows:
1. In a smoke detector system an installing and testing tool
mechanically and electrically cooperating and interlocking with a
smoke detector device, the system comprising in combination:
a smoke detector device having a permanently mounted overhead
fixture portion with a plurality of electrical contacts which are
adapted to be wired to a central station, and said device having a
detachably mounted smoked sensor portion adapted for mounting to
said fixture portion, said smoke sensor portion including a
plurality of electrical contacts positioned to match with the
contacts of the fixture portion,
said smoke sensor portion having a pair of tabs with electrical
test terminals thereon, said tabs being adapted to engage and be
grasped by an installing and testing tool;
an installing and testing tool for said smoke sensor portion, said
tool having tab engaging and grasping means, said last named means
including test probe finger means positioned to make contact with
said electrical test terminals on said tabs when said tabs are
engaged and grasped by said tool, and
said tool having extended handle means which is rotationally
operative to cause said tab engaging and grasping means to grasp
and release said tabs.
2. The invention according to claim 1 and further comprising:
said tool including an electrical source for energizing said smoke
sensor portion by way of said electrical test terminals, said tool
and smoke sensor portion providing an independently operative and
portable smoke sensor.
3. The invention according to claim 1 and further comprising:
said tool having meter means and circuit means connecting said
meter means to said test probe finger means.
4. The invention of claim 1 wherein said smoke sensor tabs are a
portion of a printed circuit board on which board the electronic
circuit of the smoke sensor.
5. The invention of claim 1 wherein said tool tab engaging and
grasping means further includes a pair of L-shaped extended fingers
adapted to reach behind said smoke sensor tabs.
6. The invention according to claim 1 wherein the smoke detector
device further comprises insert-and-rotate-to-lock bayonet type
fastening means on said two device portions for mounting and
securing said smoke sensor portion to said fixture portion, said
fastening means having no spring loading during insertion to
present no resistance to insertion; and wherein at least a portion
of the electrical contacts of said smoke detector device are
resilient and provide a spring loading on one device portion
relative to the other upon rotation-to-lock said smoke sensor
portion to said fixture portion.
7. An installing and testing tool for use with a detachably mounted
smoke detector device, the tool comprising in combination:
base member means including thereon a plurality of extended smoke
detector device engaging fingers and test probe finger means
cooperating with said extended engaging fingers, the engaging
fingers and the test probe finger means being adjustable one
relative to the other and adapted for engaging and interlocking
with tabs of a smoke detector device; and,
handle means rotatably mounted to said base member means, and cam
means connected to said handle means and positioned together with
said base member means and rotatable by said handle means to cause
said test probe finger means and said smoke detector engaging
fingers to move one relative to the other when said handle means is
being rotated with respect to said base member means.
8. The invention of claim 7 wherein said test probe finger means
provide electrical contact from test points on the tabs of a smoke
detector device through a multiconductor cable to a test set.
9. The invention of claim 7 and further comprising:
battery powered Test set means including multiconductor cable means
eletrically connected to said test probe finger means so that
operational tests can be made on a smoke detector device.
10. A method of installing and testing smoke detector heads into
ceiling fixtures using an installation and testing tool comprising
the steps of:
inserting smoke detector tab grasping means of an installation and
testing tool into a smoke detector head and rotating said tool in a
first direction until the tab grasping means contact the smoke
detector tabs;
rotating further in the first direction the handle of the tool with
respect to the smoke detector head to lock together the tool and
smoke detector head;
inserting the tool mounted smoke detector head into ceiling
fixture;
rotating the tool and smoke detector head in the first direction to
lock the smoke detector head into the ceiling fixture;
rotating still further in the first direction the handle of the
tool with respect to the now installed smoke detector head to
unlock the tool from the smoke detector head;
rotating tool in the opposite direction until the tab grasping
means are clear of the smoke detector tabs and withdrawing the tool
from the installed smoke detector head.
11. In a smoke detector system an installing and testing tool
mechanically and electrically cooperating and interlocking with a
smoke detector device having a permanently mounted overhead fixture
portion with a plurality of electrical contacts which are adapted
to be wired to a central station, and said device having a
detachably mounted smoke sensor portion adapted for mounting to
said fixture portion, said smoke sensor portion including a
plurality of electrical contacts positioned to match with the
contacts of the fixture portion, said smoke sensor portion having a
pair of tabs with electrical test terminals thereon, said tabs
being adapted to engage and be grasped by an installing and testing
tool;
the installing and testing tool comprising:
an installing and testing tool for said smoke sensor portion, said
tool having tab engaging and grasping means, said last named means
including test probe finger means positioned to make contact with
said electrical test terminals on said tabs when said tabs are
engaged and grasped by said tool, and
said tool having extended handle means which is rotationally
operative to cause said tab engaging and grasping means to grasp
and release said tabs.
12. The method of claim 10 and comprising the additional step
of:
testing said smoke detector head while said tool and smoke detector
head are locked together.
Description
BACKGROUND AND SUMMARY OF THE INVENTION
The mounting of smoke detectors at the ceiling level of an area
being protected is a normal placement. In a large building or
building complex the number of detectors used is large and may run
into the hundreds of units. In the past many of these detectors
have not been easily installed, removed, replaced, adjusted and/or
tested by a person standing on the floor below the detector. It has
generally been necessary to bring in a ladder, or the like, to
reach each detector since they are normally out of reach. In
addition, in many buildings the use of suspended ceilings is in
vogue wherein loose lay-in ceiling panels are suspended on a metal
grid frame. These panels are usually 2 .times. 4 feet in size and
relatively light in weight. To these lay-in panels the smoke
detectors are mounted.
In the smoke detectors known to applicants up to the present time,
there have been two piece units having a permanently mounted
ceiling fixture portion and a detachably mounted smoke detector
together with an installation tool, however, the assembly requires
an upward insertion force for the smoke detector portion to latch
with the ceiling fixture portion. The loose ceiling panels of the
suspended ceilings do not resist upward pressure so that ceiling
fixture and ceiling panel have a tendency to move upward with the
smoke detector as an insertion attempt is made and such an
arrangement is not entirely satisfactory. In the present invention
the smoke detector head and ceiling fixture portion are so designed
that no vertical insertion force is required to engage and lock the
smoke detector head in place and therefore the smoke detector may
easily be installed or removed from the ceiling fixture and/or
tested with the installation and testing tool by one standing on
the floor below the assembly. The installation and testing tool
mechanically and electrically connects to the smoke detector head
for installing and removing smoke detectors from the ceiling
fixtures and also provides electrical connection between the
detector test points and a test set.
To accomplish this the tool is connected to the smoke detector head
by inserting the L-shaped probes into the circular slot of the
smoke detector head and rotating the tool until the probes contact
the printed circuit test point tabs. Additional shaft or handle
rotation of the tool with respect to the head causes a cam to raise
and lock the tool onto the test point tabs. In the locked position
the tool and smoke detector head become, in effect, a single unit.
In the locked position the installation tool may be left hanging on
the smoke detector assembly. Also, in the locked position the
detector head may be removed from the ceiling fixture by turning
the tool handle counterclockwise, and may be inserted into the
ceiling fixture by rotating the tool handle clockwise. The tool is
unlocked from the head by pulling downward slightly on the handle
of the tool and rotating it clockwise whereupon the locking
mechanism snaps back to the original open or unlocked position. The
tool is then rotated counterclockwise to disengage the probes from
the circular slot of the detector head and the tool is then
withdrawn. The printed circuit test point tabs have thereon a
number of smoke detector test terminals which mate with spring
contacts on the test tool thereby providing electrical connection
from a number of points of the smoke detector head circuit to the
test set.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded view in perspective of the smoke detector
mounting and testing tool, the smoke detector head, and the
permanently mounted ceiling fixture portion;
FIG. 2 is a perspective view of the installation and testing tool
in a first position wherein it is ready to engage a smoke detector
head;
FIG. 3 is a perspective view of the installation and testing tool
in a locked position wherein the tool is locked onto the smoke
detector head;
FIG. 4 is a somewhat simplified view of the reverse side of the
smoke detector head;
FIG. 5 is a partial cross-sectional view of a portion of FIG.
4.
FIG. 6 is a detailed view of an electrical contact and locking
component of the fixture portion; and,
FIG. 7 is a schematic drawing of a smoke detector and the Test
Set.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to FIG. 1 there is disclosed an exploded perspective
view of a smoke detector installation and testing tool 10 and a
smoke detector assembly 11 comprising a detachable smoke detector
head 12 and a ceiling fixture portion 13 to be permanently mounted
and wired. The three components 10, 12 and 13 which cooperate
together are shown in axial alignment but separated for ease of
explanation.
The ceiling fixture 13 of the assembly 11 is intended to be
permanently mounted to the ceiling by mounting holes 14 and wired
to a central panel, not shown. Large numbers of smoke detector
assemblies 11 may be connected to the central panel. The fixture 13
includes a plurality of fixed electrical contacts 15 affixed
thereon of which only two have been shown in detail. In one
specific embodiment of the invention there are six such contacts,
several of which are slightly modified as in FIG. 6 to include at
one end thereof a laterally offset bayonet type latching tab 16. An
arcuate bar 17 of the fixture 13 is a positioning guide for the
sensor head 12 and the keyways 20 and 21 of the arcuate bar 17
cause the detector head 12 to be received in the proper
orientation.
The smoke detector head 12 is generally disc shaped or saucer
shaped and on the exposed surface has a raised slotted pillbox
portion 22 enclosing the smoke sensing chamber. An annular or
circular slot 23 in the face of the detector head is adapted to
receive and guide probes of the tool 10. Extending into the space
of the slot are opposite end tabs 24 and 25 of the printed circuit
board, these tabs 24 and 25 being known as the printed circuit test
point tabs. Each tab has a plurality of test points shown as pads
26, 27, 28, 30, 31 and 32. These test point tabs 24 and 25 act as
handles to be grasped by the installation and testing tool 10.
The reverse side of the detector head 12 is shown in FIG. 4. The
circular area 33 fits within and mates with the circular bar 17 of
fixture 13 and the keys 34 and 35 cooperate with keyways 20 and 21
respectively to properly orient the detector head 12 when it is
desired to engage and lock the head in place. Bayonet type latching
slots 36, 37 and 38 in the head 12 each have a widened slot portion
40 allowing the laterally offset latching tabs 16 to pass through.
The sensing head is then rotated clockwise to lock it in place on
the latching tabs 16. FIG. 4 also discloses a plurality of
resilient cammed contacts 41 which mate with the fixed contacts 15
of the fixture 13. An edge view of these resilient cammed contacts
41 is shown in FIG. 5 and it can be seen that the contact 41
extends through a rectangular opening in the circular area 33 in
such a way that the leading edge or end 42 of the resilient contact
surface is substantially lower than the opposite end 43. At the
position of insertion of detector head 12 into fixture 13 the fixed
contacts 15 align with the lower edge 42 of the contacts 41
respectively. No insertion pressure is required for this insertion
as the resilient contacts are not loaded in this insertion
position. As the detector head 12 is rotated to lock it in place,
the resilient contacts 41 are wiped by contacts 15 from edge 42 to
edge 43 and progressively pick up more loading in the process. When
the detector head is fully locked in place the resilient contacts
41 may be depressed by the loading as shown in phantom by FIG.
5.
The installation and testing tool 10 as shown in FIGS. 1, 2 and 3
comprises a shaft or handle 50 which may be of any convenient
length for an operator to reach the ceiling of the area with the
tool. The upper end of the shaft is non-rigidly affixed by a spline
type coupling to a transversely mounted arm 51 which has at the
edges thereof a pair of ramp like cam surfaces 52 and 53. The cam
carrying arm 51 rotates together with the shaft 50.
A second section of tool 10 is a rigid latching bracket 55 or base
member means which is rotatably mounted on shaft 50. Bracket 55
includes a pair of vertically positioned L-shaped smoke detector
head engaging fingers 56 and 57 which extend sufficiently to reach
into the circular slot 23 and mechanically engage behind printed
circuit tabs 24 and 25. A spring 60 urges shaft 50 upwardly with
respect to bracket 55 so that pin 61 abuts surface 62 of bracket
55. Bracket 55 also has a locking notch 63 into which pin 61 drops
in the locked position as shown in FIG. 3.
A third section of tool 10 is a spring-loaded test probe assembly
65 comprising a generally planar base section 66 having mounted
thereon pin housings 67 and 68 containing spring loaded test probes
or pins 70-75. The assembly 65 also includes locking fingers 76 and
77 which prevent printed circuit tabs 24 and 25 from slipping out
of position when the tool is in the locked position as shown in
FIG. 3. Spring members 80 and 81 tend to keep assembly 65
downwardly towards the unlocked or open position as shown in FIGS.
1 and 2.
In addition to the mechanical arrangement of the installation and
testing tool which has been described, not shown in FIGS. 1-6 are a
multiconductor cable which extends from a test set to a connector
which mounts in connector socket 82 of bracket 55. Also not shown
are the wires or cable from individual test pins 70-75 to the
connector. FIGS. 2 and 3 have been simplified to the extent of not
showing the connector socket 82.
FIG. 7 is a schematic representation of the electrical circuit of
the smoke detector, the interconnecting cable and the test set. The
details of the smoke detector circuit are described in detail in
the copending application of Larsen and Kobek Serial No. 376,011,
entitled "Smoke Detector Circuit," filed July 2, 1973, and assigned
to the same assignee, now U.S. Pat. No. 3,812,362. Reference may be
had to that case for a detailed description. Suffice it to say that
the smoke detector is an ionization type smoke detector which
provides two outputs, one being an analogue voltage output at point
31 which voltage deviates from a clean air voltage as a function of
the smoke density being sensed. The other output is a switched
output at point 27 which indicates by switching that a
predetermined smoke level has been exceeded. This switching is done
by a comparator switching circuit. The smoke detector is to be used
in a system not here shown. The test terminals 26, 27, 28, 30, 31,
32 are the printed circuit board test points of the same number
shown in FIG. 1.
FIG. 7 shows schematically the test probe pins 70-75 of tool 10 and
a flexible multiconductor cable 83 which interconnects the test
probe pins to the test set 84. Conductors 70', 71', 72', 73', 74'
and 75' of the test set correspond to test probe pins 70-75,
respectively. The test set includes a first two level rotary wafer
switch S2 which has a first rotary contact 85 which selectively
contacts fixed contacts a, b, c, d and e, of which the last e is
not used, and which has a second rotary contact 86, ganged to the
first contact 85, which likewise contacts fixed contacts a', b',
c', d', and e' of which only the last e' is used. The conductors
71', 72', 74' and 75' are directly connected to fixed contacts a,
b, c, and d respectively. The conductor 70' is directly connected
to fixed contact e'.
The test set includes a second two level rotary wafer switch S2
which has a first rotary contact 90 which selectively contacts
fixed contacts f, g, h and i, and which has a second rotary contact
91, ganged to contact 90, which likewise contacts fixed contacts
f', g', h' and i'. Fixed contacts f', g' and i are directly
connected to ground conductor 73'. Contact i is connected by a
resistor 92 to the conductor 71', the conductor 71' also being
connected by an alarm lamp 93 to the rotary contact 86. The rotary
contacts 90 and 91 of switch 52 connect to the terminals of a meter
94. Associated with switch 52 are a pair of transistors 95 and 96
connected in an emitter follower configuration. The base of
transistor 95 is directly connected to conductor 72' and the
emitter is connected by a load resistor 97 to conductor 73' and by
resistors 98 and 99 to fixed contacts g and h. The base of
transistor 96 is connected to conductor 74' and the emitter is
connected to contacts f and h' and by a load resistor 100 to
conductor 73'.
The system wiring to the smoke detector provides a B.sup.+ voltage
to conductor 70' and ground potential on conductor 73' of the test
set thus powering the test set when the smoke detector head is
installed, the system power is on and the test tool 10 is locked
onto the installed head. If the system power is off, the power to
run the test set is supplied by internal batteries 101 connected
across terminals 70' and 73'. An on-off switch S4 and a diode is
also in this internal battery circuit. A normally open "Test"
switch S1 is connected from conductor 70' to conductor 75'. A
normally open "Reset" switch S3 is connected from conductor 70' to
conductor 72'.
The test set 84 includes a comparator section 110 which is
energized from the B.sup.+ line 70' and which has a signal input
conductor 111 connected to rotary contact 85 of switch S6.
Conductor 111 connects to one output terminal 112 of a resistive
bridge circuit which bridge is energized from line 70'. The bridge
comprises resistors 113, 114, 115, 116 and 117. The bridge also has
output terminals 120 and 121 which provide fixed bias voltages, the
voltage at terminal 112 being controlled by the voltage picked up
on rotary contact 85 except in position e.
The comparator section 110 also includes two IC amplifiers 122 and
123 which may be type 741's. Bridge output terminals 120 and 121
are connected to the negative (inverting) input of amplifier 122
and the positive (non inverting) input of amplifier 132,
respectively. Bridge output terminal 112 is connected to the
positive input of amplifier 122 and to the negative input of
amplifier 123. The output terminals of amplifiers 122 and 123 are
connected to the contact electrodes of transistors 124 and 125,
respectively, and turn on the transistor when the amplifier output
is positive, the transistors 124 and 125 having indicator lamp L1
and L2 in their collector load circuit.
OPERATION
The legend of FIG. 7 indicates how a number of checks and
measurements can be made with the test set 84 on the smoke detector
head 12 whether or not it is installed in the ceiling fixture 13.
Let it first be assumed that the tool 10 and the smoke detector
head 12 are locked together and that it is desired to test the
detector head prior to installation in a ceiling fixture. The test
battery 101 provides the necessary power for the detector head and
the test set. Considering first the switch S2 and the indicating
meter 84 which are used in test of the detector head. During this
test the switch S6 should be in the e position which, as indicated
in the legend is the detector test position. By rotating the switch
S2 through the positions f, g, h and i the voltages which may be
read on the meter 94 in order are the analogue voltage at terminal
31, the set point voltage at terminal 28, the voltage and
differential between the set point and the analogue voltage, and
the voltage at the detector output terminal 27. The same test can
be made on the smoke detector head when it is installed in the
ceiling fixture 13 and operating from system power.
The test set 84 is also designed to test the field wiring
interconnecting ceiling fixture 13 and a cental station. The
selector switch S6 and a comparator circuit 110 with indicating
lamps L1 and L2 is used for this test. As pointed out by the
legend, the positioning of switch arm 85 at positions a, b, c or d
provides test of the alarm wiring, set point wiring, the analogue
wiring, and the test wiring. A high positive voltage on input lead
111 causes lamp L1 to glow while a lower ground potential on the
input lead causes the lamp L2 to glow. If an erroneous voltage is
discovered during this test the switch S5 can be actuated to
determine whether the voltage being sensed is AC or DC.
During the test of the smoke detectors and particularly in switch
position S2i, a smoke condition can be simulated by the switch S1
which causes the switch in the smoke detector to turn on and short
to ground the terminal 27. The reset switch S3 can be then
depressed when it is desired to reestablish the initial standby
condition of the smoke detector. A voltage on meter 94 will
indicate the switching and the reset.
* * * * *