WO2019099832A1 - Detection article - Google Patents

Abstract

A detection article is disclosed for detecting smoke, ionized gas, or other materials wherein upper and lower housings of the article are releasably attached by at least one boss pair and at least one snap pair to reduce incidences of access to electronic components inside the two housings to reduce misuse or abuse of the article.

Description

DETECTION ARTICLE

CLAIM OF PRIORITY

[0001] This application claims priority from U.S. Provisional Patent

Application Serial Number 62/587,726 bearing Attorney Docket Number 12017027 and filed on November 17, 2017, which is incorporated by reference.

FIELD OF THE INVENTION

[0002] This invention concerns detection articles such as smoke detectors having tamper-resistant features.

BACKGROUND OF THE INVENTION

[0003] Occupied buildings have benefitted from the use of smoke and heat detectors to alert humans to possible unsafe heat or smoke conditions. These appliances can be electrically powered via electrical communication to the electrical circuitry of the building or electrically powered via dry cell batteries. Mounted in strategic locations to either walls, ceilings, or both, early warning from these detectors can save human life and minimize property damage.

[0004] Economical production of any useful article should be a goal to bring the value of the article to the marketplace at minimum production cost without a sacrifice of performance of the article or quality of the production of that article.

SUMMARY OF THE INVENTION

[0005] What the art needs is a reassessment of a detection article from the perspective of reducing production costs without any significant diminution in performance of the detection article or the quality of the production of the detection article. [0006] The present invention accomplishes that goal by reconfiguring the locations of functional components of the detection article in a manner which provides functionality to reduce incidence of attempts to open the detection article by unqualified personnel.

[0007] One aspect of the invention is a detection article comprising (a) an upper housing; (b) a lower housing; and (c) an electronics board positioned between the upper housing and the lower housing, wherein the upper housing has at least one component of a snap pair and at least one component of a boss pair and wherein the lower housing has at least one mating component of the snap pair and at least one mating component of the boss pair.

[0008] The number of multiple boss pairs and snap pairs can be the same or different. Desirably, at least two boss pairs and at least two snap pairs, with a preference for at least three or even four boss pairs and at least three or even four snap pairs can be used.

[0009] Further aspects of the invention are identified below with reference to the Drawing.

BRIEF DESCRIPTION OF THE DRAWING

[00010] FIG. 1 is an exploded line drawing of the detection article from a perspective which permits viewing of the outer surface of the upper housing and the inner surface of the lower housing.

[00011] FIG. 2 is an exploded line drawing of the detection article from a perspective which permits viewing of the outer surface of the lower housing and the inner surface of the upper housing.

[00012] FIG. 3 is a cross-sectional view of a boss pair.

[00013] FIG. 4 is a cross-sectional view of a snap pair.

EMBODIMENTS OF THE INVENTION

[00014] Detection Article [00015] Referring to FIG. 1 and FIG. 2, the detection article 10 is made of three essential parts: the upper housing 100, the lower housing 200, and the electronics circuit board 300 configured to be positioned between the housings 100 and 200 when finally assembled for operation.

[00016] The upper housing 100 has an inside surface 102, an outside surface 104, and an edge surface 106. The edge surface 106 can have a curvature (generally 108) which can be ornamentally attractive of the detection article 10 which is an appliance removably mounted to a wall or a ceiling of an occupied building.

[00017] The lower housing 200 has an inside surface 202, an outside surface 204, and an edge surface 206. The edge surface 206 can have a curvature (generally 208) which also can be ornamentally attractive of the detection article 10 for the same reason as the curvature 108 of the upper housing 100.

[00018] Both of the housings 100 and 200 are conventionally circular in shape (and annular in three dimensional form when considering edge surfaces 106 and 206), although the shape is not a limitation for use of the invention. Besides a circular geometry, the detection article could be elliptical, triangular, rectangular (including square), trapezoidal, or any other X and Y geometry suitable for construction of a safety appliance for an occupied building with sufficient thickness Z to accommodate the board 300.

[00019] The electronics circuit board 300 also has an upper surface 302, a lower surface 304, and an edge surface 306. Upon accommodation and configuration of the board 300 within housings 100 and 200, the upper surface 302 is in proximity to the inside surface 102 of upper housing. Moreover, the lower surface 304 of board 300 is in removable mounting configuration to the inside surface 202 of lower housing 200. Mounting (not shown) can occur by at least one screw into a receptacle, pressure fit connections of aligned projecting and receiving elements, and other means suitable for ease of assembly and removal by those expert persons having access to the interior space of the detection article 10 where the board 300 resides.

[00020] The board 300 is the location for the electronic components 310 required to be in air communication with the outside of the detection article 10. At least two types of components 310 are conventionally used. A speaker 312 is removably mounted (optionally in the same manner as used for the board 300 itself) to the board 300 and in air communication with the outside of the detection article 10 so that an audible alert designed for use by the speaker can be heard by occupants of the building without the audible alert being muffled or otherwise reduced in volume. Also, a detector 314 of smoke, ionized gas, or other indicator of danger (only seen in FIG. 1) is removably mounted

(optionally in the same manner as used for the board 300 itself) to the board 300 and in air communication with the outside of the detection article 10 so that the indicator of danger can be detected in air flow from beyond the detection article 10 by electronics in the detection article 10 for electrical and electronic communication to electronic circuitry 316 (details not shown) assembled on the board 300 on either upper surface 302, lower surface 304, or both (as shown in FIGS. 1 and 2).

[00021] To assist in the placement of the electronic components 310 in the upper housing 100, for the speaker 312, there is a speaker alignment port 112 on the inside surface 102 of upper housing 100. Also for the detector 314, there is a detector alignment port 114 on the inside surface 102 of upper housing 100.

[00022] These sensitive, complex, and expensive electronic components 310 (i.e., at least speaker 312 and air flow detector 314) mounted on the upper surface 302 of the board 300 and electronic circuitry 316 optionally mounted on the upper surface 302 of the board 300 need to be protected from amateur efforts to open the detection article 10 to examine, adjust, replace, or otherwise interfere with the operation of the detection article 10. Incidences of non- operational detection articles can occur because of unauthorized handling of the components 310 and the circuitry 316.

[00023] To reduce the number of such amateur and potentially dangerous incidences, the lower housing 200 on its inside surface 202 can have projections in the form of an inaccessibility wall 212, a reinforcement wall 214, and at least one ribbing 216 used to assist the removable mounted board 300 from lower housing 200, all configured to add strength to the detection article 10 and reduce opportunities for an unauthorized person to gain access to the any circuitry 316 mounted on the lower surface 304 of electronics board 300.

[00024] The inaccessibility wall 212 extends from the inside surface 202 of the lower housing 200 toward the lower surface 304 of the electronics board 300, such that when the board 300 is assembled onto the inside surface 202, the circuitry 316 is blocked from view and blocked from physical access by an unauthorized person. The speaker 312 and the detector 314 rising from the upper surface 302 of the board reside between the housings 100 and 200 and is also blocked from view and physical access because of residence on the upper surface 302 of board 300.

[00025] Lower housing 200 can also benefit from a reinforcement wall 214 which not only can provide reinforcement of the support of the board 300 to removable mounting to the lower housing but also provide additional reinforcement of the connections between the lower housing 200 and the upper housing 100 when fully and finally assembled.

[00026] Lower housing 200 between its inside surface 202 and its outside surface 204 has an aperture 220 to access one or more batteries 320 (four shown in FIG. 1 and FIG. 2) contained on the lower surface 304 of the electronics board 300. The aperture optionally may be covered by a door (not shown). The combination of the inaccessibility wall 212 and the aperture 220 permit the user of the detection article 10 to change the battery(ies) 320 without permitting the user to gain access to the electronic components 310 or the other electronic circuitry 316 on the board 300. [00027] After the board 300 is removably mounted on the inside surface 202 of the lower housing 200, the upper housing 100 and the lower housing 200 are configured to be removably attached to complete assembly of the detection article 10. The means of removable attachment contribute to minimizing protecting the detection article 10 from amateur or unauthorized access to the board 300 and especially the components 310 on upper surface 302 and circuitry 316 on upper surface 302 or lower surface 304 or both.

[00028] There are two means of removable attachment: mating boss pairs and mating snap pairs.

[00029] The upper housing 100 has at least one component 130 of a boss pair projecting from the inside surface 102 which is configured to mate with a mating component 230 of the boss pair of the same number on the inside surface 202 of the lower housing 200. As seen in FIG. 1 and FIG. 2, each projecting boss 130 resides on the inside surface 102 of the upper housing 100, while each receiving boss 230 resides on the inside surface 202 of the lower housing 200.

[00030] The number of projecting bosses 230 and receiving bosses 130 desirably can be two with a preference for three or four pairs of bosses 130, 230 for security from access to inside the upper and lower housings 100, 200 other than through the aperture 220 for access to the batteries 320. FIGS. 1 and 2 depict four boss pairs, although only three projecting bosses 130 can be seen in FIG 1 because of the angle of the perspective view.

[00031] Alternatively, the configuration of one or more boss pairs could be reversed such that at least one projecting boss 130 could reside on the inside surface 202 of lower housing 200 and its receiving boss 230 pair could reside on the inside surface 102 of upper housing 100.

[00032] As seen in FIG. 3, showing the alternative configuration identified immediately above, each mating projecting boss 130 and receiving boss 230 are configured to have concentric diameters of sufficient in size for the pair of bosses to mate. Preferably, a projecting boss 130 slides into a receiving boss 230, shown in cross-section, to provide a mating of the bosses 130 and 230 as a pressure fit.

[00033] The use of two more boss pairs releasably engaged by pressure fitted provides security against unauthorized access to the electronics board.

For additional security, at least one boss optionally can be drilled to permit a screw or other mechanical connect project from either boss to its mating boss.

If it is desired to have screw connection from the outside of the housings, it is preferred for that mechanical connection to be accessible from outside surface 204 of lower housing 200 via recesses 232 (three seen in FIG. 2) than from outside surface 104 of upper housing 100 for cosmetic or ornamental reasons.

[00034] The upper housing 100 has at least one component 140 of a snap pair from the inside surface 102 which is configured to mate with a mating component 240 of the snap pair of the same number on the inside surface 202 of the lower housing 200. As seen in FIG. 1 and FIG. 2, each projecting snap 140 resides on the inside surface 102 of the upper housing 100, while each receiving snap 240 resides on the inside surface 202 of the lower housing 200.

[00035] The number of projecting snaps 140 and receiving snaps 240 desirably can be two with a preference for three or four pairs of bosses 140, 240 for security from access to inside the upper and lower housings 100, 200 other than through the aperture 220 for access to the batteries 320.

[00036] Alternatively, the configuration of one or more snap pairs could be reversed such that at least one projecting snap 140 could reside on the inside surface 202 of lower housing 200 and its receiving snap 240 of the pair could reside on the inside surface 102 of upper housing 100.

[00037] As seen in FIG. 4, the snap projection on projecting snap 140 is typically in the shape of a wedge 142 of increasing width from the terminus which resolves to a flat shoulder 144 about 4 mm from the terminus. The receiving snap 240 is typically an entry surface 242 for the wedge 142 of the projecting snap 140 to slide under pressure against the entry surface 242 until the flat shoulder 144, farther from the terminus than the wedge 142, slides past the end of the entry surface 242 for shoulder 144 to contact shoulder surface 244 on the receiving snap 240. The sliding involves deflection of the projecting snap 140 at the wedge 142 until the entry surface 242 is passed, whereupon the projection snap 140 at wedge 142“snaps” back into normal position and shoulders 144 and 244 contact one another without continued deflection of the projecting snap 140 at wedge 142. Disconnection requires a reversal of this process, with the initial energy needed to disconnect shoulder 144 from shoulder 244 much greater than the initial energy to slide and snap. This differential is another deterrent to the unauthorized user to gain access between upper housing 100 and lower housing 200. Moreover, disconnection requires deflection of all wedge projections from surfaces at the same time, requiring the use of both hands of the authorized person or use of a special tool.

[00038] Significant to this invention is the array of bosses 130 and 230 and snaps 140 and 240 as removable means for securing upper and lower housings 100 and 200 together after assembly and during use. The projecting bosses 130 and the projecting snaps 140 are shown in FIG. 1 and FIG. 2 to be on the upper housing 100. But the projecting bosses 130 and the projecting snaps 140 could reside on opposite housings 100 and 200, respectively. An amateur possessing the detection article 10 would need to overcome the fact that the removably attached housings 100 and 200 need to have action on two types of attachment of the housings 100 and 200 to detach those housings from each other. This complexity might deter the amateur from attempting to gain access to the electronic components 310 and circuitry 316. Moreover, by providing access to the battery(ies) 320 via aperture 220 in lower housing 200, there is no need for the amateur to gain access to inside either housing 100 or 200 to perform the routine maintenance of changing batteries.

[00039] Thwarting an amateur from gaining access to components 310 and circuitry 316 is a feature of this invention which has safety considerations. Appliances such as detection article 10 involve qualification under

governmental regulations or industrial standards with structures which not only function properly but also are designed to minimize misuse or abuse of the appliance. For example, listing of an electrical appliance by Underwriters’ Laboratories (ul.com) is a prerequisite to introducing that appliance to the market. The projections of bosses 130 and the projections of snaps 140 from upper housing 100 provide additional features to help the appliance listing process required for successful commerce and also help to reduce the incidence of misuse or abuse of the detection article 10 when in use in occupied buildings. Alternatively, the projections of bosses 130 from the lower housing 200 and the projections of snaps 140 from opposing housings 200 and 100, respectively, further add to the complexity of disassembly by an unauthorized person seeking to gain access to the electronics board 300.

[00040] The separation of the boss pairs 130 and 230 and the snap pairs 140 and 240 from each can be symmetrical or asymmetrical within the inside surface 102 near the edge surface 106 of the upper housing 100 and within the inside surface 202 near the edge surface 206 of the lower housing 200.

Desirably, both types of connection pairs are symmetrically aligned with reference to edge surfaces 106 and 206, although it can be preferable to have one of the two types of connection pairs, bosses or snaps, to be asymmetrical to guide assembly more efficiently to achieve proper orientation of the two housings 100 and 200 for assembly of the detection article 10.

[00041] As seen in FIGS. 1 and 2, there are four boss pairs and four snap pairs each 90 degrees apart from each other, respectively.

[00042] Another feature of the detection article 10 is the location of airflow louvers 150 (also called baffles) in the edge surface 106 of upper housing 100. Flow of air through the upper housing can move past electronic components 310, especially detector 314. The angle of the louvers 150 can be configured to direct air reaching a curved surface into a laminar flow past detector 314. If the detector 14 detects smoke, ionized gas, or other fluid for which it was designed, the circuitry 316 causes the speaker 312 to annunciate an alert. As is also conventional, low battery warnings can emit a“chirp” to remind occupants to change the batteries when remaining potential energy is low.

[00043] Many other conventional features of a detection article 10 are contemplated for optional use in the detection article 10, including without limitation battery indicators, alarm reset buttons, activation lights, and the like.

[00044] Moreover, ornamental appearances for the detection article 10 as an appliance in an occupied building can be included, such as the radiating dimples 160 generally seen on the outer surface 104 of upper housing 100.

[00045] Materials for the Housings

[00046] Polyvinyl Halides

[00047] Any polyvinyl halide is a candidate for use as the polymer for housings 100 and 200 in this invention, because of their inherent flame retardant properties arising from the presence of halide moieties which naturally retard onset and continuity of combustion in the presence of oxygen. Polyvinyl chloride polymers are presently preferred.

[00048] Polyvinyl chloride polymers are widely available throughout the world. Polyvinyl chloride resin (PVC), as referred to herein, includes polyvinyl chloride homopolymers, vinyl chloride copolymers, graft copolymers, and vinyl chloride polymers polymerized in the presence of any other polymer such as a heat distortion temperature enhancing polymer, impact toughener, barrier polymer, chain transfer agent, stabilizer, plasticizer or flow modifier.

[00049] For example a combination of modifications may be made with the PVC polymer by overpolymerizing a low viscosity, high glass transition temperature (Tg) enhancing agent such as SAN resin, or an imidized

polymethacrylate in the presence of a chain transfer agent.

[00050] In another alternative, vinyl chloride may be polymerized in the presence of said Tg enhancing agent, the agent having been formed prior to or during the vinyl chloride polymerization. However, only those resins possessing the specified average particle size and degree of friability exhibit the advantages applicable to the practice of the present invention. [00051] In the practice of the invention, there may be used polyvinyl chloride homopolymers or copolymers of polyvinyl chloride comprising one or more comonomers copolymerizable therewith. Suitable comonomers for vinyl chloride include acrylic and methacrylic acids; esters of acrylic and methacrylic acid, wherein the ester portion has from 1 to 12 carbon atoms, for example methyl, ethyl, butyl and ethylhexyl acrylates and the like; methyl, ethyl and butyl methacrylates and the like; hydroxyalkyl esters of acrylic and methacrylic acid, for example hydroxymethyl acrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate and the like; glycidyl esters of acrylic and methacrylic acid, for example glycidyl acrylate, glycidyl methacrylate and the like; alpha, beta unsaturated dicarboxylic acids and their anhydrides, for example maleic acid, fumaric acid, itaconic acid and acid anhydrides of these, and the like;

acrylamide and methacrylamide; acrylonitrile and methacrylonitrile;

maleimides, for example, N-cyclohexyl maleimide; olefin, for example ethylene, propylene, isobutylene, hexene, and the like; vinylidene chloride, for example, vinylidene chloride; vinyl ester, for example vinyl acetate; vinyl ether, for example methyl vinyl ether, allyl glycidyl ether, n-butyl vinyl ether and the like; crosslinking monomers, for example diallyl phthalate, ethylene glycol dimethacrylate, methylene bis-acrylamide, tracrylyl triazine, divinyl ether, allyl silanes and the like; and including mixtures of any of the above comonomers.

[00052] The present invention can also use chlorinated polyvinyl chloride (CPVC), wherein PVC containing approximately 57% chlorine is further reacted with chlorine radicals produced from chlorine gas dispersed in water and irradiated to generate chlorine radicals dissolved in water to produce CPVC, a polymer with a higher glass transition temperature (Tg) and heat distortion temperature. Commercial CPVC typically contains by weight from about 58% to about 70% and preferably from about 63% to about 68% chlorine. CPVC copolymers can be obtained by chlorinating such PVC copolymers using conventional methods such as that described in U.S. Pat. No. 2,996,489, which is incorporated herein by reference. Commercial sources of CPVC include Lubrizol Corporation.

[00053] The preferred composition is a polyvinyl chloride homopolymer.

[00054] Commercially available sources of polyvinyl chloride polymers include OxyVinyls LP of Dallas, TX and Shintech USA of Freeport, TX.

[00055] Compounds of Polyvinyl Halides

[00056] Thermoplastic resin compounds typically contain a variety of additives selected according to the performance requirements of the article produced therefrom well within the understanding of one having ordinary skill in the art without the necessity of undue experimentation.

[00057] But it is significant for this disclosure that the PVC mixture not contain any additives which could appreciably decrease the performance properties of the PVC for housings 100 and 200.

[00058] Of all possible thermoplastic compounds, polyvinyl chloride polymer homopolymers whose inherent viscosity ranges from 0.4 to 1.3, preferably 0.5 to 0.8 are presently preferred for use in making mixtures of this invention.

[00059] PVC compounds are commercially available under the Geon™ brand from PolyOne Corporation.

[00060] Optional Additives

[00061] The PVC compounds can include conventional plastics additives in an amount that is sufficient to obtain a desired processing or performance property for the compound. The amount should not be wasteful of the additive nor detrimental to the processing or performance of the compound. Those skilled in the art of thermoplastics compounding, without undue

experimentation but with reference to such treatises as Plastics Additives Database (2004) from Plastics Design Library (elsevier.com), can select from many different types of additives for inclusion into the compounds of the present invention. [00062] Non-limiting examples of optional additives include adhesion promoters; biocides (antibacterials, fungicides, and mildewcides), anti-fogging agents; anti-static agents; bonding, blowing and foaming agents; dispersants; fillers and extenders; fire and flame retardants and smoke suppresants; impact modifiers; initiators; lubricants; micas; pigments, colorants and dyes;

plasticizers; processing aids; release agents; silanes, titanates and zirconates; slip and anti-blocking agents; stabilizers; stearates; ultraviolet light absorbers; viscosity regulators; waxes; and combinations of them.

[00063] Processing

[00064] The preparation of compounds of the present invention is uncomplicated. The compound of the present can be made in batch or continuous operations.

[00065] Mixing in a continuous process typically occurs in an extruder that is elevated to a temperature that is sufficient to melt the polymer matrix with addition either at the head of the extruder or downstream in the extruder of the solid ingredient additives. Extruder speeds can range from about 50 to about 500 revolutions per minute (rpm), and preferably from about 100 to about 300 rpm. Typically, the output from the extruder is pelletized for later extrusion or molding into polymeric articles.

[00066] Mixing in a batch process typically occurs in a Banbury mixer that is also elevated to a temperature that is sufficient to melt the polymer matrix to permit addition of the solid ingredient additives. The mixing speeds range from 60 to 1000 rpm and temperature of mixing can be ambient. Also, the output from the mixer is chopped into smaller sizes for later extrusion or molding into polymeric articles, such as housings 100 and 200.

[00067] Subsequent molding techniques are well known to those skilled in the art of thermoplastics polymer engineering. Without undue

experimentation but with such references as "Handbook of Molded Part Shrinkage and Warpage"; "Specialized Molding Techniques"; and "Handbook of Mold, Tool and Die Repair Welding", all published by Plastics Design Library (elsevier.com), one can make articles of any conceivable molded shape and appearance using compounds to form housings 100 and 200 within the scope of the present invention.

[00068] Electronic Components, Circuitry, and Circuit Board

[00069] The electronic board 10 and its various parts 312, 314, 316, and 320 are commercially available from a variety of sources worldwide, because of the essential ubiquity of detection articles in occupied buildings as a matter of fire code regulations. These components are protected by the configurations of housings 100 and 200 as disclosed in this document, whereby a person must disconnect the two housings by two different means.

USEFULNESS OF THE INVENTION

[00070] As stated above, both governmental regulations and industry standards (often for insurance reasons) call for the use of danger detection articles in occupied buildings. The housings 100 and 200 combine to reduce the possibility of misuse or abuse of this important electrical appliance.

[00071] The invention is not limited to the claimed embodiments. The claims follow.

Claims

What is claimed is:

1. A detection article, comprising:

(a) an upper housing;

(b) a lower housing; and

(c) an electronics board positioned between the upper housing and the lower housing,

wherein the upper housing has at least one component of a snap pair and at least one component of a boss pair and

wherein the lower housing has at least one mating component of the snap pair and at least one mating component of the boss pair.

2. The article of Claim 1,

wherein each snap pair comprises one projecting snap and one receiving snap,

wherein each boss pair comprises one projecting boss and one receiving boss, and

wherein the upper housing and the lower housing are releasably attached by a boss pair and a snap pair.

3. The article of Claim 2, wherein the upper housing has an inside surface and at least one projecting boss residing in the inside surface and wherein the upper housing has at least one projecting snap residing on the inside surface.

4. The article of Claim 2, wherein the lower housing has an inside surface and at least one projecting boss residing in the inside surface and wherein the lower housing has at least one projecting snap residing on the inside surface.

5. The article of Claim 2, wherein the upper housing has an inside surface and at least one projecting boss residing in the upper housing inside surface and wherein the lower housing has an inside surface and has at least one projecting snap residing on the lower housing inside surface.

6. The article of any one of Claims 3-5,

wherein boss pairs and snap pairs are multiple and the same in number.

7. The article of any one of Claims 3-5,

wherein boss pairs and snap pairs are multiple and different in number.

8. The article of any one of Claims 1-7, wherein there are two snap pairs.

9. The article of any one of Claims 1-7, wherein there are three snap pairs.

10. The article of any one of Claims 1-7, wherein there are four snap pairs.

11. The article of any one of Claims 1-7, wherein there are two boss pairs.

12. The article of any one of Claims 1-7, wherein there are three boss pairs.

13. The article of any one of Claims 1-7, wherein there are four boss pairs.

14. The article of any one of Claims 1-13, wherein the electronics board is releasably mounted to the lower housing and wherein the electronics board has an upper surface upon which electronic components are mounted.

15. The article of Claim 14, wherein the upper housing has an edge surface with air flow louvers and wherein the electronic components are a speaker and a detector of air flow through the louvers.

16. The article of Claim 14, wherein electronics board has a lower surface having removable batteries in communication with an aperture on the lower housing.

17. The article of Claim 16, wherein the lower housing has an inaccessibility wall to reduce access to the electronics board from the aperture.

18. The article of Claim 15 wherein electronics board has a lower surface having removable batteries in communication with an aperture on the lower housing, wherein the lower housing has an inaccessibility wall to reduce access to the electronics board from the aperture, and wherein the combination of the inaccessibility wall and the lower surface of the electronics board reduce access to the speaker and the detector of air flow.