CA1099366A - Roof alarm - Google Patents
Roof alarmInfo
- Publication number
- CA1099366A CA1099366A CA304,300A CA304300A CA1099366A CA 1099366 A CA1099366 A CA 1099366A CA 304300 A CA304300 A CA 304300A CA 1099366 A CA1099366 A CA 1099366A
- Authority
- CA
- Canada
- Prior art keywords
- switch
- roof
- alarm
- hanging member
- condition
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
- E04B7/00—Roofs; Roof construction with regard to insulation
- E04B7/02—Roofs; Roof construction with regard to insulation with plane sloping surfaces, e.g. saddle roofs
-
- G—PHYSICS
- G08—SIGNALLING
- G08B—SIGNALLING SYSTEMS, e.g. PERSONAL CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- G08B21/00—Alarms responsive to a single specified undesired or abnormal condition and not otherwise provided for
- G08B21/18—Status alarms
- G08B21/182—Level alarms, e.g. alarms responsive to variables exceeding a threshold
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H35/00—Switches operated by change of a physical condition
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Architecture (AREA)
- Electromagnetism (AREA)
- Civil Engineering (AREA)
- Structural Engineering (AREA)
- Business, Economics & Management (AREA)
- Emergency Management (AREA)
- General Physics & Mathematics (AREA)
- Buildings Adapted To Withstand Abnormal External Influences (AREA)
- Emergency Alarm Devices (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
An alarm system for detecting downward bending of a roof under a snow load. A hanging member is pivotally connected to a rafter and is adjustable in length so that its bottom can be located a preset distance above a mat-type pressure switch supported on the joists. When the roof deflects sufficiently, the bottom of the hanging member presses the mat switch and changes the switch condition, triggering an alarm.
An alarm system for detecting downward bending of a roof under a snow load. A hanging member is pivotally connected to a rafter and is adjustable in length so that its bottom can be located a preset distance above a mat-type pressure switch supported on the joists. When the roof deflects sufficiently, the bottom of the hanging member presses the mat switch and changes the switch condition, triggering an alarm.
Description
~9366 This invention relates to an alarm system for detecting the downward bending of a portion of a roof under a load, particularly a snow load, and for gener-ating an alarm signal when the roof portion has bent downwardly a predetermined amount, and to an alarm device adapted to be used in such a system.
A cottage intended for inhabitation only durinc~ the summer months is commonly of less sturdy construction than a residential home intended for continuous inhabitation. An owner of such a cottage is usually concerned with the build up of snow on the cottage roof during the winter months when the cottage is uninhabitated and is commonly required to travel from time to time to the cottage to clear away the snow from the cottage roof before the roof collapses under the weight of the snow. However, some of the trips to the cottage may be unnecessary as there may be insuf-ficient snow on the roof to cause it to collapse and, furthermore, there is no assurance that the trips to the cottage, even if made at frequent intervals, will ta~e place before the roof has collapsed under the weight o~ the snow.
~ t is therefore an object of the present invention to provide an alarm system, and an alarm device adapted to be used in such a system, for detecting the downward bending of a cottage roof under a load, particularly a snow load, and for generating an alarm signal when the roof has bent downwardly a predetermined amount, the alarm signal indicating that the roof is heing severely stressed and may collapse 3~
I, .
unless corrective actlon is taken.
In its broadest aspect the invention provides an alarm device adapted to be used in an alarm sys~em Eor detecting the downward bendiny of a portion of a roof under a load, comprising:
a) a rigid hanging member having an upper and a lower end portion, the upper end portion adapted to be pivotally connected to the roo~ portion, and b) switch means having first and second switch portions, said second switch portion being an activating portion so that when said second switch portion presses against said firs-t switch portion the condition of said switch will change, c) one of said switch portions being mounted at the bottom of said lower end portion and the other of said switch portions being adapted to be disposed a predetermined distance below said one switch portion, so that, upon the roof portion bending downwardly the predetermined distance, the one switch portion may press against the other switch portion to change the condition o~ said switch means, so that the alarm system may indicate an alarm condition.
Further objects and advantages of the present invention will become apparent from the following descrip~
tion of a preferred embodiment, considered together with the accompanying drawings in which:
Fig. 1 is an e~ploded perspective view of an alarm device constructed according to a preferred ernbodi-ment of the invention pivotally connected to a section ~ 3 --of a rafter of a portion of a cottage roof;
Fig. 2 is a front view of the alarm device of Fig. 1 pivotally connected to an unloaded rafter of a portion of a cottage roof;
Fig. 3 is a front view of -the alarm device of Fig. 1 pivotally connected to a rafter oE a portion of a cottage roof loaded under a snow load;
Fig. 4 is a block diagram showing connection o~ the switch of the alarm device of Fig. 1 to a siren;
Fig. 5 is a block diagram showing connection of the switch of the alarm device of Fig. 1 to an auto-matic telephone dialer; and Fig. 6 is a perspective view of a modified hanging member of an an alarm device of the invention.
Reference is first made to Fig. 1 and 2, which show an alarm device 10 constructed according to a preferred embodiment of the invention. The alarm device 10 has a rigid hanging member 12 and a pressure-activated switch 14 located on a support 16.
The hanging member 12 is a telescopic rod having an upper tube 18 and a lower tube 20. The upper tube 18 has a horizontal hole 22 extending through i~s upper end, so that a pivot pin 24, such as a nail, can be inserted through the hole 22 to pivotally connect the tube 18 to a rafter 26 of a roo~ 28.
The lower tube 20 telescopically receives the upper tube 18, the two being fixed together by a screw 30. At its bottom the lower tube 20 carries a horizontal plate 32. The plate 32 can be fixed to the lower tube 20 by any conventional means, for e~ample by screw 34.
-- 4 ~
.
3~
The total length of the telescopic rod is adjusted so that the bottom of plate 32 hangs at a predetermined distance dl above the pressure switch 14 when the roof is unloaded.
The tubes 18, 20 and the plate 32 are fabricated from a rigid material, preferably a thermo-set plastic or fibreglass. Metal is preferably not used since metal may attract condensatlon which could short out the switch 14 (unless a waterproof switch is used), and since the condensation could freeze which may tend to cause false alarms. Wood is preferably not used since it tends to warp and twist. The plate member 32 may be conveniently moulded as a single unit with the lower tube 20 if desired.
The pressure-activated switch 14 is a conven-tional switch mat similar to those commonly used in super-markets and the like to open a door when a person steps on the mat. The support 16 for the switch 14 rests on the ceiling joists 34 and is normally sufficiently large so that it extends across adjacent joists. The switch 14 has output leads 38 and 40 so that it may be connected to an alarm system (nc* shown). Normally the switch 14 is open and closes when pressed.
The rafter 26 of the roof 28 is commonly wood and can bend considerably under the weight of a snow load before breaking. The exact arnount that the rafter can bend before breaking depends on the particular wood and the manner in which the roof 28 is constructed. However, as an example, a 2" x 6,i wooden beam, about ten feet 0 in length, can commonly deflect at least four inches 3~
before breaking.
Reference is next made to Fig. 3. When the roof 28, and conse~uently the rafter 26 as well, is in an unloaded state, the bottom of the plate 32 is disposed a distance dl above the switch 14 on the ceiling joist 34. As the roof 26 is loaded under a snow load 27, the rafter 24 bends lnwardly and downwardly assuming a gènerally concave shape as shown in Fig. 3. ~he ma~imum amount that the rafter 24 can bend inwardly and down-wardly before breaking is indicated by distance d2. Asthe raf-ter 24 bends through the distance d2, the rod 12 moves a distance d3 downwardly closer to the joist 34, d3 being an amount less than d2, and a distance d4 horizontally inwardly toward the centre of the building.
It will be seen that the predetermined distance dl which the bottom of plate 32 must be disposed above the switch 14 must be less than distance d3. To allow an adequate safety margin, and to allbw time to remove snow after the alarm has sounded, but at the same time to reduce the frequency of false alarms, distance dl will typically be between 1/4 and 1/2 of distance d3.
In order to take advantage of the maximum deflection of the rafter 26, the pivot pin 24 of the hanging member 12 is preferably located slightly upwardly of the mid-portlon of the rafter. If the rafter is divided into four quarters, indicated at 27a, 27b, 27c and 27d, then the pivot pin 24 is preferably located in the third quarter 27c, where the rafter movement vertically is likely to be the greatest. In addition, because of the horizontal movement of the hanging member , 12 as the rafter bends, the pressure switch 14 and the support 16 are lengthened in the direction of distance d4, to ensure that a portion of the pressure switch will always be beneath the plate 32.
The output leads 36, 38 of the switch 14 are connected to conventional means for generating an alarm.
For example they may be connected to an alarm detector 40 (Fig. 5) which when it detects an alarm (i.e. when switch 14 closes) enables a power supply 42. The power supply 4~ produces a signal which operates a siren 44 whose sound can be heard by a watchman supervising the cottages in ques-tion. If no watchman is available, then as shown in Fig. 5, the alarm detector 40 may constitute one input to a conventional automatic telephone dialer 46 which is programmed to dial a predetermined number, for e~ample the home telephone of the cottage owner, and to continue dialing until an answer is received over telephone line 48. Many such dialers have two inputs, one for a fire alarm and one for a burglar alarm (and they produce two different messages depending on which report is actuated). Since in winter months a fire is unlikely, the fire alarm input of the dialer can be connected to the roof alarm detector 40.
It will be realized that different forms of hanging member 12 may be used, so long as they are rigid and stable in form. In addition, instead of a simple nail 24, a plate having a pivot pin projecting therefrom may be nailed to the rafter and the upper tube 18 can be held thereon by a cotter pin inserted through a ho]e in the pivot pin. This ensures that the hanging mernber 12 will pivot freely at all times and eliminates the likelihood that the nail 24 may be driven into the rafter so tightly as to restrict pivotal movement of the hanging member 12.
The telescopic form of the hanging member is greatly preferred, since this faciliates positioning of the hanging member in the centre of the rafter and simplifies adjustment to ensure the desired distance dl bet.ween the plate 32 and switch 14. However, if desired, a non~telescopic member can be used and can be cut to length during installation. This is likely to lead to inaccuracy in setting the distance dl however and is not preferred. However, upper and lower members 18', 20' can be of rectangular cross-section if desired, as shown in Fig. 6, and may be clamped together at the desired total length by any conventional clamp, such as the screw-type clamp ring 50 which is commonly used for hoses and small ducts.
The switch 14 need not be a pressure switch of the kind described; any simp]e pressure operated switch may be used. For example a microswitch can be mounted on the support 16 and operated by contact with the plate 32 (or it can instead be mounted on the plate 32~. However, a mat-type switch extending over a substantial area is preferred in case the plate 32 tilts as it descends and in case the rafter 26 deflects irregularly as it descends. Alternatively the bottom of the plate 32 and the top of support 16 be surfaced with .
a conductive material so that when the two touch, a circult to the alarm detector 40 is completed. However, ~Q~.3~i5 since exposed conductive surfaces may oxidize and not make a reliable connection when they touch, again a sealed mat-type switch is preferred. In addition, installation of the device is simplified if there is no wiring connected to the hanging member 12.
If desired, a time delay may be included in the alarm detector 40 so that the switch 14 must remain closed for at least 30 seconds, for example, before an alarm is generated. The time delay may be provided by a timer diagrammatically indicated at 52, Figs. 4 and 5, and which produces an output signal only after it has received a continuous input for at least 30 seconds. This will help to reduce false alarms due for example to high gusting winds.
g _
A cottage intended for inhabitation only durinc~ the summer months is commonly of less sturdy construction than a residential home intended for continuous inhabitation. An owner of such a cottage is usually concerned with the build up of snow on the cottage roof during the winter months when the cottage is uninhabitated and is commonly required to travel from time to time to the cottage to clear away the snow from the cottage roof before the roof collapses under the weight of the snow. However, some of the trips to the cottage may be unnecessary as there may be insuf-ficient snow on the roof to cause it to collapse and, furthermore, there is no assurance that the trips to the cottage, even if made at frequent intervals, will ta~e place before the roof has collapsed under the weight o~ the snow.
~ t is therefore an object of the present invention to provide an alarm system, and an alarm device adapted to be used in such a system, for detecting the downward bending of a cottage roof under a load, particularly a snow load, and for generating an alarm signal when the roof has bent downwardly a predetermined amount, the alarm signal indicating that the roof is heing severely stressed and may collapse 3~
I, .
unless corrective actlon is taken.
In its broadest aspect the invention provides an alarm device adapted to be used in an alarm sys~em Eor detecting the downward bendiny of a portion of a roof under a load, comprising:
a) a rigid hanging member having an upper and a lower end portion, the upper end portion adapted to be pivotally connected to the roo~ portion, and b) switch means having first and second switch portions, said second switch portion being an activating portion so that when said second switch portion presses against said firs-t switch portion the condition of said switch will change, c) one of said switch portions being mounted at the bottom of said lower end portion and the other of said switch portions being adapted to be disposed a predetermined distance below said one switch portion, so that, upon the roof portion bending downwardly the predetermined distance, the one switch portion may press against the other switch portion to change the condition o~ said switch means, so that the alarm system may indicate an alarm condition.
Further objects and advantages of the present invention will become apparent from the following descrip~
tion of a preferred embodiment, considered together with the accompanying drawings in which:
Fig. 1 is an e~ploded perspective view of an alarm device constructed according to a preferred ernbodi-ment of the invention pivotally connected to a section ~ 3 --of a rafter of a portion of a cottage roof;
Fig. 2 is a front view of the alarm device of Fig. 1 pivotally connected to an unloaded rafter of a portion of a cottage roof;
Fig. 3 is a front view of -the alarm device of Fig. 1 pivotally connected to a rafter oE a portion of a cottage roof loaded under a snow load;
Fig. 4 is a block diagram showing connection o~ the switch of the alarm device of Fig. 1 to a siren;
Fig. 5 is a block diagram showing connection of the switch of the alarm device of Fig. 1 to an auto-matic telephone dialer; and Fig. 6 is a perspective view of a modified hanging member of an an alarm device of the invention.
Reference is first made to Fig. 1 and 2, which show an alarm device 10 constructed according to a preferred embodiment of the invention. The alarm device 10 has a rigid hanging member 12 and a pressure-activated switch 14 located on a support 16.
The hanging member 12 is a telescopic rod having an upper tube 18 and a lower tube 20. The upper tube 18 has a horizontal hole 22 extending through i~s upper end, so that a pivot pin 24, such as a nail, can be inserted through the hole 22 to pivotally connect the tube 18 to a rafter 26 of a roo~ 28.
The lower tube 20 telescopically receives the upper tube 18, the two being fixed together by a screw 30. At its bottom the lower tube 20 carries a horizontal plate 32. The plate 32 can be fixed to the lower tube 20 by any conventional means, for e~ample by screw 34.
-- 4 ~
.
3~
The total length of the telescopic rod is adjusted so that the bottom of plate 32 hangs at a predetermined distance dl above the pressure switch 14 when the roof is unloaded.
The tubes 18, 20 and the plate 32 are fabricated from a rigid material, preferably a thermo-set plastic or fibreglass. Metal is preferably not used since metal may attract condensatlon which could short out the switch 14 (unless a waterproof switch is used), and since the condensation could freeze which may tend to cause false alarms. Wood is preferably not used since it tends to warp and twist. The plate member 32 may be conveniently moulded as a single unit with the lower tube 20 if desired.
The pressure-activated switch 14 is a conven-tional switch mat similar to those commonly used in super-markets and the like to open a door when a person steps on the mat. The support 16 for the switch 14 rests on the ceiling joists 34 and is normally sufficiently large so that it extends across adjacent joists. The switch 14 has output leads 38 and 40 so that it may be connected to an alarm system (nc* shown). Normally the switch 14 is open and closes when pressed.
The rafter 26 of the roof 28 is commonly wood and can bend considerably under the weight of a snow load before breaking. The exact arnount that the rafter can bend before breaking depends on the particular wood and the manner in which the roof 28 is constructed. However, as an example, a 2" x 6,i wooden beam, about ten feet 0 in length, can commonly deflect at least four inches 3~
before breaking.
Reference is next made to Fig. 3. When the roof 28, and conse~uently the rafter 26 as well, is in an unloaded state, the bottom of the plate 32 is disposed a distance dl above the switch 14 on the ceiling joist 34. As the roof 26 is loaded under a snow load 27, the rafter 24 bends lnwardly and downwardly assuming a gènerally concave shape as shown in Fig. 3. ~he ma~imum amount that the rafter 24 can bend inwardly and down-wardly before breaking is indicated by distance d2. Asthe raf-ter 24 bends through the distance d2, the rod 12 moves a distance d3 downwardly closer to the joist 34, d3 being an amount less than d2, and a distance d4 horizontally inwardly toward the centre of the building.
It will be seen that the predetermined distance dl which the bottom of plate 32 must be disposed above the switch 14 must be less than distance d3. To allow an adequate safety margin, and to allbw time to remove snow after the alarm has sounded, but at the same time to reduce the frequency of false alarms, distance dl will typically be between 1/4 and 1/2 of distance d3.
In order to take advantage of the maximum deflection of the rafter 26, the pivot pin 24 of the hanging member 12 is preferably located slightly upwardly of the mid-portlon of the rafter. If the rafter is divided into four quarters, indicated at 27a, 27b, 27c and 27d, then the pivot pin 24 is preferably located in the third quarter 27c, where the rafter movement vertically is likely to be the greatest. In addition, because of the horizontal movement of the hanging member , 12 as the rafter bends, the pressure switch 14 and the support 16 are lengthened in the direction of distance d4, to ensure that a portion of the pressure switch will always be beneath the plate 32.
The output leads 36, 38 of the switch 14 are connected to conventional means for generating an alarm.
For example they may be connected to an alarm detector 40 (Fig. 5) which when it detects an alarm (i.e. when switch 14 closes) enables a power supply 42. The power supply 4~ produces a signal which operates a siren 44 whose sound can be heard by a watchman supervising the cottages in ques-tion. If no watchman is available, then as shown in Fig. 5, the alarm detector 40 may constitute one input to a conventional automatic telephone dialer 46 which is programmed to dial a predetermined number, for e~ample the home telephone of the cottage owner, and to continue dialing until an answer is received over telephone line 48. Many such dialers have two inputs, one for a fire alarm and one for a burglar alarm (and they produce two different messages depending on which report is actuated). Since in winter months a fire is unlikely, the fire alarm input of the dialer can be connected to the roof alarm detector 40.
It will be realized that different forms of hanging member 12 may be used, so long as they are rigid and stable in form. In addition, instead of a simple nail 24, a plate having a pivot pin projecting therefrom may be nailed to the rafter and the upper tube 18 can be held thereon by a cotter pin inserted through a ho]e in the pivot pin. This ensures that the hanging mernber 12 will pivot freely at all times and eliminates the likelihood that the nail 24 may be driven into the rafter so tightly as to restrict pivotal movement of the hanging member 12.
The telescopic form of the hanging member is greatly preferred, since this faciliates positioning of the hanging member in the centre of the rafter and simplifies adjustment to ensure the desired distance dl bet.ween the plate 32 and switch 14. However, if desired, a non~telescopic member can be used and can be cut to length during installation. This is likely to lead to inaccuracy in setting the distance dl however and is not preferred. However, upper and lower members 18', 20' can be of rectangular cross-section if desired, as shown in Fig. 6, and may be clamped together at the desired total length by any conventional clamp, such as the screw-type clamp ring 50 which is commonly used for hoses and small ducts.
The switch 14 need not be a pressure switch of the kind described; any simp]e pressure operated switch may be used. For example a microswitch can be mounted on the support 16 and operated by contact with the plate 32 (or it can instead be mounted on the plate 32~. However, a mat-type switch extending over a substantial area is preferred in case the plate 32 tilts as it descends and in case the rafter 26 deflects irregularly as it descends. Alternatively the bottom of the plate 32 and the top of support 16 be surfaced with .
a conductive material so that when the two touch, a circult to the alarm detector 40 is completed. However, ~Q~.3~i5 since exposed conductive surfaces may oxidize and not make a reliable connection when they touch, again a sealed mat-type switch is preferred. In addition, installation of the device is simplified if there is no wiring connected to the hanging member 12.
If desired, a time delay may be included in the alarm detector 40 so that the switch 14 must remain closed for at least 30 seconds, for example, before an alarm is generated. The time delay may be provided by a timer diagrammatically indicated at 52, Figs. 4 and 5, and which produces an output signal only after it has received a continuous input for at least 30 seconds. This will help to reduce false alarms due for example to high gusting winds.
g _
Claims (12)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An alarm device adapted to be used in an alarm system for detecting the downward bending of a portion of a roof under a load, comprising:
a) a rigid hanging member having an upper and a lower end portion, the upper end portion adapted to be pivotally connected to the roof portion; and b) switch means having first and second switch portions, said second switch portion being an activating portion so that when said second switch portion presses against said first switch portion the condition of said switch will change, c) one of said switch portions being mounted at the bottom of said lower end portion and the other of said switch portions being adapted to be disposed a predetermined distance below said one switch portion, so that, upon the roof portion bending downwardly the predetermined distance, the one switch portion may press against the other switch portion to change the condition of said switch means, so that the alarm system may indicate an alarm condition.
a) a rigid hanging member having an upper and a lower end portion, the upper end portion adapted to be pivotally connected to the roof portion; and b) switch means having first and second switch portions, said second switch portion being an activating portion so that when said second switch portion presses against said first switch portion the condition of said switch will change, c) one of said switch portions being mounted at the bottom of said lower end portion and the other of said switch portions being adapted to be disposed a predetermined distance below said one switch portion, so that, upon the roof portion bending downwardly the predetermined distance, the one switch portion may press against the other switch portion to change the condition of said switch means, so that the alarm system may indicate an alarm condition.
2. The alarm device as defined in claim 1 wherein said upper end portion of said lower end portion are separate members, said hanging member including means for securing said upper and lower end portions together in a plurality of positions so that the length of said hanging member can be adjusted.
3. The alarm device as defined in claim 2 wherein said one switch portion is said second switch portion and comprises a horizontal plate member adapted to be connected to the bottom of said lower end portion of the hanging member.
4. The alarm device as claimed in claim 3 wherein said other switch portion is a sealed pressure-operated switch having a switch operating surface of substantial area so that pressing of said plate member anywhere on said surface will change the condition of said switch means.
5. The alarm device as defined in claim 2, 3 or 4 wherein said first and second end portions are tele-scopically interfitted and are formed of a non-metallic substantially warp-free material.
6. An alarm system for detecting the downward bending of a portion of a cottage roof under a load, comprising:
a) a rigid hanging member having an upper and a lower end portion, the upper end portion being pivotally connected to the roof portion, b) switch means having first and second switch portions, said second switch portion being an activating portion so that when said second switch portion presses against said first switch portion the condition of said switch will change, c) one of said switch portions being mounted at the bottom of said lower end portion and the other of said switch portions being supported on a joist a predetermined distance below said one switch portion, so that, upon the roof portion bending downwardly a predetermined distance, the one switch portion presses against the other switch portion to change the condition of said switch means so that the alarm system may indicate an alarm condition.
a) a rigid hanging member having an upper and a lower end portion, the upper end portion being pivotally connected to the roof portion, b) switch means having first and second switch portions, said second switch portion being an activating portion so that when said second switch portion presses against said first switch portion the condition of said switch will change, c) one of said switch portions being mounted at the bottom of said lower end portion and the other of said switch portions being supported on a joist a predetermined distance below said one switch portion, so that, upon the roof portion bending downwardly a predetermined distance, the one switch portion presses against the other switch portion to change the condition of said switch means so that the alarm system may indicate an alarm condition.
7. The alarm system as defined in claim 6 wherein said upper end portion and said lower end portion are separate members, said hanging member including means for securing said upper and lower end portions together in a plurality of positions so that the length of said hanging member can be adjusted.
8. The alarm system as defined in claim 7 wherein said one switch portion is said second switch portion and comprises a horizontal plate member connected to the bottom of said lower end portion of the hanging member.
9. The alarm system as claimed in claim 8 wherein said other switch portion is a sealed pressure-operated switch having a switch operating surface of substantial area so that pressing of said plate member anywhere on said surface will change the condition of said switch means.
10. The alarm system as defined in claim 7, 8 or 9 wherein said first and second end portions are tele-scopically interfitted and are formed of a non-metallic substantially warp-free material.
11. The alarm device as defined in claim 7, 8 or 9 wherein said first and second end portions are tele-scopically interfitted and are formed of a non-metallic substantially warp-free material, and including auto-matic telephone dialer means connected to said switch means and responsive to said change in condition of said switch means for transmitting a telephone alarm.
12. The alarm system as claimed in claim 7, 8 or 9 wherein said roof portion is a rafter of said roof, said rafter extending from a side of said roof to an apex, said hanging member being pivoted to said rafter at a portion between one-half and three-quarters of the way along said rafter from said side to said apex.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA304,300A CA1099366A (en) | 1978-05-29 | 1978-05-29 | Roof alarm |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA304,300A CA1099366A (en) | 1978-05-29 | 1978-05-29 | Roof alarm |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1099366A true CA1099366A (en) | 1981-04-14 |
Family
ID=4111571
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA304,300A Expired CA1099366A (en) | 1978-05-29 | 1978-05-29 | Roof alarm |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1099366A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL1030866C2 (en) * | 2006-01-06 | 2007-07-09 | Hermanus Johannes Visser | Monitoring method of load on roof of building involves using sensor to detect phenomenon related to load exerted on roof and emitting warning signal from sensor when detected phenomenon is different from predetermined phenomenon values |
| US7646309B2 (en) | 2006-01-06 | 2010-01-12 | Hermanus Johannes Visser | Method and device for monitoring roof loads |
| CN108518006A (en) * | 2018-04-12 | 2018-09-11 | 佛山科学技术学院 | A kind of heat-insulating top of cement building |
| CN108955497A (en) * | 2018-08-06 | 2018-12-07 | 中国冶集团有限公司 | It is a kind of to pass through mouthful check device and method for jack truss in space tube truss |
-
1978
- 1978-05-29 CA CA304,300A patent/CA1099366A/en not_active Expired
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL1030866C2 (en) * | 2006-01-06 | 2007-07-09 | Hermanus Johannes Visser | Monitoring method of load on roof of building involves using sensor to detect phenomenon related to load exerted on roof and emitting warning signal from sensor when detected phenomenon is different from predetermined phenomenon values |
| US7646309B2 (en) | 2006-01-06 | 2010-01-12 | Hermanus Johannes Visser | Method and device for monitoring roof loads |
| CN108518006A (en) * | 2018-04-12 | 2018-09-11 | 佛山科学技术学院 | A kind of heat-insulating top of cement building |
| CN108955497A (en) * | 2018-08-06 | 2018-12-07 | 中国冶集团有限公司 | It is a kind of to pass through mouthful check device and method for jack truss in space tube truss |
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