CA2026331A1 - Self-adjusting slide assembly for weight on gear switch - Google Patents
Self-adjusting slide assembly for weight on gear switchInfo
- Publication number
- CA2026331A1 CA2026331A1 CA002026331A CA2026331A CA2026331A1 CA 2026331 A1 CA2026331 A1 CA 2026331A1 CA 002026331 A CA002026331 A CA 002026331A CA 2026331 A CA2026331 A CA 2026331A CA 2026331 A1 CA2026331 A1 CA 2026331A1
- Authority
- CA
- Canada
- Prior art keywords
- cross tube
- gear
- mounting bracket
- slide assembly
- switch
- 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.)
- Abandoned
Links
- 230000003534 oscillatory effect Effects 0.000 claims abstract 7
- 125000006850 spacer group Chemical group 0.000 description 8
- 239000002184 metal Substances 0.000 description 5
- 239000004809 Teflon Substances 0.000 description 3
- 229920006362 Teflon® Polymers 0.000 description 3
- 229910000831 Steel Inorganic materials 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64C—AEROPLANES; HELICOPTERS
- B64C25/00—Alighting gear
- B64C25/32—Alighting gear characterised by elements which contact the ground or similar surface
- B64C25/52—Skis or runners
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64C—AEROPLANES; HELICOPTERS
- B64C25/00—Alighting gear
- B64C25/32—Alighting gear characterised by elements which contact the ground or similar surface
- B64C2025/325—Alighting gear characterised by elements which contact the ground or similar surface specially adapted for helicopters
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Aviation & Aerospace Engineering (AREA)
- Body Structure For Vehicles (AREA)
- Railway Tracks (AREA)
Abstract
SELF-ADJUSTING SLIDE ASSEMBLY
FOR WEIGHT ON GEAR SWITCH
ABSTRACT OF THE DISCLOSURE
A self-adjusting slide assembly is provided for mounting a weight on gear switch to an aircraft. The slide assembly is particularly adapted for mounting on a skid equipped helicopter for responding to vertical oscillatory deflection of a cross tube of the skid landing gear. A mounting bracket is attached to the underside of the helicopter for supporing a back plate and a pair of clamp plates. A C-shaped slide member has a flange mounted between the back plate and clamp plates so as to slide vertically. Take-off and landing stresses cause the cross tube to exhibit vertical oscillatory deflection between an upper arm and a lower arm of the slide member. A microswitch mounted on the lower arm is actuated when the cross tube contacts a bottom bumper on the lower arm while the helicopter is fully on skid gear. Any deviation of the cross tube beyond its normal limits of deflection causes the upper and lower arms of the slide member to move with respect to the mounting bracket to establish new limits for cross tube oscillatory deflection. Thus, the microswitch maintains approximately the same relative position with respect to the mean position of the cross tube oscillatory deflection regardless of any permanent deformation of the cross tube resulting from harder than normal landings.
FOR WEIGHT ON GEAR SWITCH
ABSTRACT OF THE DISCLOSURE
A self-adjusting slide assembly is provided for mounting a weight on gear switch to an aircraft. The slide assembly is particularly adapted for mounting on a skid equipped helicopter for responding to vertical oscillatory deflection of a cross tube of the skid landing gear. A mounting bracket is attached to the underside of the helicopter for supporing a back plate and a pair of clamp plates. A C-shaped slide member has a flange mounted between the back plate and clamp plates so as to slide vertically. Take-off and landing stresses cause the cross tube to exhibit vertical oscillatory deflection between an upper arm and a lower arm of the slide member. A microswitch mounted on the lower arm is actuated when the cross tube contacts a bottom bumper on the lower arm while the helicopter is fully on skid gear. Any deviation of the cross tube beyond its normal limits of deflection causes the upper and lower arms of the slide member to move with respect to the mounting bracket to establish new limits for cross tube oscillatory deflection. Thus, the microswitch maintains approximately the same relative position with respect to the mean position of the cross tube oscillatory deflection regardless of any permanent deformation of the cross tube resulting from harder than normal landings.
Description
--~ 2 ~2~
SELP-ADJUSTING SLIDE ASSEMBLY
FOR WEIGHT ON GEAR SWITCH
TECHNICAL FIELD
Thls lnventlon relates to alrcraft welght on gear swltches and, in partlcular, to ~ self-ad~ustlng sllde assembly for mountlng an alrcraft welght on gear swltch.
" ~'~';,' ~ .;
SELP-ADJUSTING SLIDE ASSEMBLY
FOR WEIGHT ON GEAR SWITCH
TECHNICAL FIELD
Thls lnventlon relates to alrcraft welght on gear swltches and, in partlcular, to ~ self-ad~ustlng sllde assembly for mountlng an alrcraft welght on gear swltch.
" ~'~';,' ~ .;
- 2~2~33~ ~
, BACXGROUND OF l~IE INVENTION
Sophlstlcated alrcraft generally lnclude a welght on gear swltch for actlvatlng and deactlvatlng varlous alrcraft systems and fllght controls dependlng upon whether the alrcraft ls airborne or fully supported by the landlng gear on the ground. In some alrcraft, such as hellcopters, the welght on gear swltch also provldes an indlcatlon to the pllot that the alrcraft ls elther alrborne or on the ground.
Aircraft welght on gear swltches, or squat switches, are typlcally actuated by a maln landlng gear strut when compressed to support the welght of the alrcraft. On hellcopters wlth skid landlng gear systems, paddles or slmllar devlces have been used to actually contact the ground surface upon landlng of the hellcopter. However, swltches deslgned to contact the ground are generally unrellable because of collectlon of dlrt and debris or damage from skld movement and ob~ects on the ground. In addltlon, ground contact swltches can glve erroneous lndlcatlons when the hellcopter ls landlng on uneven terraln.
Other types of hellcopter welght on gear swltches have been based on collectlve stlck posltlon or englne torque. However, these types of swltches generally can be overridden by the pllot so that they can lndlcate the alrcraft ls ~lrborne when it ls actually on the ground.
Another type of welght on gear swltch for skld gear helicopters ls mounted so as to detect deflectlon of a cross tube of the skld landlng gear. Thls placement of the welght on gear swltch overcomes many of the dlsadvantages of the ground contact or collective stlck ~' posltlon swltches. However, swltches mounted to lndlcate deflectlon of the skid gear cross tube requlre perlodlc ad~ustment as a result of repeated cross tube ... ...... .
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deflection from normal landlngs and permanent deformation from harder than normal landlngs. Wlthout such periodlc ad~ustment, welght on gear swltches can glve erroneous lndlcatlons that can affect fllght safety.
Therefore, there ls a need for a mountlng assembly for a hellcopter welght on gear swltch that is self-ad~ust1ng both for normal landlng deflection of the skld gear cross tube and for permanent deformation of the cross tube resultlng from hard landlngs.
:
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1~ . . . ` . :
$33~
SUMMARY OF THE INVENTION
The present lnventlon ls a self-ad~ustlng sllde assembly for an alrcraft welght on gear swltch. A
preferred embodlment of the sllde assembly ls partlcularly ~dapted for mounting a welght on gear swltch to detect the osclllatory deflectlon of a skld landlng gear cross tube on a hellcopter.
A mountlng bracket of the self-ad~ustlng sllde assembly ls mounted to the underslde of the hellcopter fuselage ln close proxlmity to the center of a cross tube of the skld landlng gear. A back plate extends vertlcally downward from the mountlng bracket. A palr of vertlcal clamp plates are attached to the back plate by fastenlng means so as to form a vertlcal channel lS between the clamp plates and a vertlcal groove between each of the clamp plates and the back plate. A sllde member has a T-shaped flange along one edge thereof for slldably mountlng ln the channel and grooves formed by the back plate and the clamp plates. The fastenlng means may be tlghtened or loosened to ad~ust the force necessary to move the sllde member vertlcally ln the channel ~nd grooves.
The sllde member has a generally C-shaped conflguratlon wlth upper and lower arms. The sllde member ls mounted so that the arms extend above and below the cross tube of the hellcopter skld landlng gear. Durlng take-off and landlng, the cross tube of the landlng gear deflects a known dlstance ln the vertlcal dlrectlon. Deflectlon of the cross tube causes lt to contact a top bumper on the upper arm when the hellcopter ls alrborne and to contact a bottom bumper on the lower arm when the weight of the hellcopter ls on the landlng gear. A mlcroswltch ls mounted on the iower arm sc as to extend vertlcally ~ust above the bottom '~'""" ' ~' '' ' ;2~3r bumper. When the hellcopter lands, the mlcroswltch ls actlvated by the cross tube as lt deflects agalnst the bottom bumper. The bottom bumper protects the mlcroswltch from damage by llmitlng the extent of s contact between the cross tube and the mlcroswltch. The top and bottom bumpers of the sllde member are spaced apart to accommodate the normal vertlcal osclllatory deflectlon of the cross tube about a mean positlon durlng take-off and landlng.
Although the mlcroswltch ls mounted on the slide member to detect the normal range of cross tube deflection, repeated landlngs or harder than normal landlngs can cause the cross tube to be temporarlly or permanently deflected from lts orlglnal mean posltlon ;~
lS wlth respect to the hellcopter. However, the sllde -~
assembly of the present lnventlon automatlcally ad~usts the posltlon of the mlcroswltch durlng each take-off and ;
landlng cycle of the hellcopter to correspond to any change ln the mean posltlon of the cross tube. For example, lf the cross tube ls permanently deflected downward durlng a hard landlng, the cross tube contacts the bottom bumper and moves the entlre sllde member downward relatlve to the bracket attached to the -~
fuselage of the hellcopter. Tnus, the mlcroswltch on the lower arm ls moved downward an amount correspondln~
to the permanent deflectlon of the cross tube so that the normal downward deflectlon of the cross tube upon landlng contlnues to actuate the mlcroswltch.
6 2~633~
BRIEF DESCRIPTION OF THE DRAWINGS
For a more complete understandlng of the present lnventlon and for further advantages thereof, reference ls made to the followlng Descrlption of the Preferred s Embodlment taken in con~unctlon wlth the accompanylng Drawlngs, ln whlch:
FIGURE 1 lllustrates the lnstallatlon of the present inventlon on a hellcopter havlng a skld landlng gear system; and FIGURE 2 ls a perspectlve vlew of the self-ad~ustlng sllde assembly of the present lnventlon.
''; ~
7 ~2~3~L
`
DESCRIPTION OF T}IE PREFERRED EMBODIMEN~
FIGURE 1 shows a self-ad~ustlng sllde assembly 10 of the present lnventlon mounted on the underslde of the fuselage of a hellcopter 11. Hellcopter 11 ls equlpped wlth a skld landlng gear assembly 12 lncludlng ~ cross tube 14 attached to hellcopter 11 by mountlng polnts 13.
Sllde assembly 10 ls mounted ln close proxlmlty to the center of the cross tube 14 between mountlng polnts 13 so that vertlcal osclllatory deflectlon of cross tube 14 about a mean posltlon actuates a weight on gear swltch to lndlcate whether hellcopter 11 ls alrborne or on the ground. Assembly 10 should preferzbly be mounted on rear cross tube 14, as excesslve aft cycllc can transfer vlrtually the entlre welght of the hellcopter from front cross tube 14 to rear cross tube 14 when the hellcopter -ls on the ground. A welght on gear swltch mounted to -~
front cross tube 14 ln thls sltuatlon would falsely -~-~
lndlcate that the hellcopter was alrborne. Thls phenomenon, however, ls not normally exhlblted wlth rear cross tube 14 when full forward cycllc is applled, thus maklng the rear cross tube 14 the preferred posltlon for attachment at assembly 10. Whlle two swltches can be used, one on the front and one on the rear cross tube, preferably only one at the rear cross tube ls used.
FIGURE 2 ls a perspectlve vlew of sllde assembly 1 removed from hellcopter 11. Sllde assembly 10 lncludes a mountlng bracket 16 for mountlng sllde assembly lO to the underside of hellcopter 11. A back plate 18 extends vertlcally downward from mountlng bracket 16. Back plate 18 may comprlse an extenslon of mountlng bracket 16 and/or a separate spacer plate 19 attached to mountlng bracket 16. A palr of vertlcal clamp plates 20 --are attached to back plate 18 by a plurallty of fastenlng means 22, such as nuts, bolts, and washers.
8 ~ 3 ~ ~
Clamp plates 20 may be laminated or lnclude multlple plates such as an lnner wear plate 20a and an outer support plate 20b. Clamp plates 20 are attached to back plate 18 so as to provlde a vertlcal channel 21 between clamp plates 20 and a vertlcal groove 23 between each clamp plate 20 and spacer plate 19.
In the preferred embodlment, mountlng bracket 16 and back plate 18 are constructed of metal spacer plate 19 and lnner wear plate 20a ls preferably constructed from a self-lubricatlng plastlc such as Teflon or ~el-F.
Outer wear plate 20b ls preferably constructed of metal.
The use of self-lubrlcatlng plastlcs ~s useful for ease of malntenance. It ls posslble to use metal ln place of plastlc, however, use of metal would requlre malntenance, lubrlcatlon and preferably a cover to prevent contamlnatlon of the surfaces.
A generally C-shaped sllde member 24 has a T-shaped flange 25 along lts vertlcal edge. T-shaped flange 25 ls adapted to be engaged between clamp plates 20 and spacer plate 19 so that sllde member 24 extends through vertlcal channel 21 and flange 25 slides ln grooves 23 between clamp plates 20 and spacer plate 19. Clamp plate 20a and spacer plate 19 should be made of Teflon or a simllar self-lubrlcatlng plastlc materlal havlng a coefflclent of frlctlon that facllltates slldlng movement of sllde member 24 ln grooves 23 between clamp plates 20 and spacer plate 19. ~n order to prevent corroslon, flange 25 should preferably be made of stalnless steel. Other sultable materlals would lnclude <30 Teflon coated or plastlc coated metal parts.
Sllde member 24 has a lower arm 26 that lncludes a swltch mount 27 and a slot 28 for conflnlng a bottom bumper 29. Sllde member 24 also has an upper arm 30 wlth a top bwmper 32. Top bumper 32 may comprlse, for 2 ~ 3 ~ `
~. ~
example, a section of shrlnk tublng formed about upper arm 30.
Sllde member 24 ls mounted so that upper ~rm 30 extends above cross tube 14 and lower arm 26 extends S below cross tube 14. Arms 26 and 30 are deslgned to extend past the landlng edge of cross tube 14 so as to prevent decoupllng from assembly 10 upon deflectlon of the cross tube durlng a run on landlng. A horlzontal sxtenslon of about 1/2 inch beyond the leading edge of the cross tube, which is slzed to incur a vertlcal deflectlon of about 0.5 lnches when welght of the hellcopter ls added to the landlng gear, has been found -~
to be sufflclent for thls purpose ln the current embodlment of assembly 10. The degree of extension of arms 26 and 30 can be of any length sufflclent to prevent decoupllng of the assembly when the cross tube deflects. Preferably, the assembly 10 ls mounted such that back plate 18 ls on the rear slde of the cross tube.
Durlng take-off and landlng, cross tube 14 normally deflects from a lower positlon agalnst bottom bumper 29 when the welght of hellcopter 11 ls fully on skld gear 12, to an upper posltlon agalnst top bumper 32 when hellcopter 11 ls alrborne. A mlcroswltch 34 mounted on swltch mount 27 extends vertlcally sllghtly above bottom bumper 29 so that cross tube 14 actuates mlcroswltch 34 when hellcopter 11 ls fully on skld gear 12 and cross tube 14 ls ln contact wlth bottom bumper 29. Bottom bumper 29 protects mlcroswltch 14 from any hard contact wlth cross tube 14. As wlll be appreclated, the bumpers are spaced to accommodate the normal deflectlon of the cross tube. The swltch mechanlsm should have a sufflclent length of travel for actlvatlon to prevent false slgnals from vlbratlons. Also preferable, the p~. ,..... .. ... : - ........................... - . ~ : , .
,~. ~ : , ' , !.
2 ~ 3 ~ ---~ 10 swltch is spaced apart from the cross tube when there ls no welght on the gear. It has been found that a cross tube, sized to deflect about 0.5 lnches ln the vertlcal dlrectlon when the welght of the hellcopter ls added to the landlng gear, can be usefully employed ln the present lnventlon. A swltch havlng a travel of about 0.125 lnches or more has been found useful ln the present lnvention.
After repeated landlngs or harder than normal landlngs, the mean posltlon of the osclllatory deflectlon of cross tube 14 may become temporarlly or permanently dlsplaced from lts origlnal posltlon wlth respect to mountlng bracket 16. In prlor art welght on gear swltches, excessive deflectlon of cross tube 14 could cause erroneous fllght lndlcatlons affectlng fllght safety unless the posltlon of the welght on gear swltch was manually ad~usted.
Durlng normal take-offs and landings, cross tube 14 exhlbits osclllatory deflectlon between top bumper 32 and bottom bumper 29, and actuates mlcroswltch 34 when ln contact wlth bottom bumper 29. Because sllde member 24 ls slldably mounted between spacer plate 19 and clamp plates 20, any deflectlon of cross tube 14 beyond lts normally establlshed llmlts causes sllde member 24 to sllde so that top bumper 32 and bottom bumper 29 define new llmlts for osclllatory deflectlon of cross tube 14.
For example, lf a harder than normal landlng causes cross tube 14 to deflect, temporarlly or permanently, further from the fuselage of hellcopter 11, cross tube 14 contacts bottom bumper 29 and forces sllde member 24 to sllde downward to the llmlt of the downward deflectlon of cross tube 14. Because microswltch 34 ls -mounted on lower arm 26, lts posltion ls moved downward a dlstance correspondlng to the downward deflectlon of ;: :: ,: . . .
,~ ,~....
",, ' ~ 11 20~6~3~r cross tube 14 agalnst bottom bumper 29. Llkewlse, any upward deflection of cross tube 14 beyond lts normally establlshed llmlt causes cross tube 14 to contact top bumper 32 and move sllde member 24 upward. Thus, mlcroswltch 34 always malntalns approxlmately the same relatlve posltlon with respect to the mean posltlon of the osclllatory deflectlon of cross tube 14 regardless of any permanent deformatlon of cross tube 14. -The pressure between plates 20a and 19 and flange 25 ls regulated by the torque applled to bolts 22. In order to properly compensate for osclllatory deflection of cross tube 14, thls pressure should be such that approxlmately 35 pounds of force ls requlred to move sllde member 24 vertlcally up or down through vertlcal channel 21. Greater or lesser torque can be applled to the bolts to ad~ust the force requlred to move the slide member. The force selected before movement of the sllde member ls allowed can vary and be ad~usted dependlng upon the degree of sensltlvlty deslred, the slze of the hellcopter and the deflectlon characterlstlcs of the cross tube.
Although the present lnventlon has been descrlbed wlth respect to a speclflc embodlment partlcularly adapted for skld gear hellcopters, varlous changes and modlflcatlons may be suggested to one skllled ln the art to adapt the present lnventlon to other landlng gear systems, for example, and lt ls lntended that the present lnventlon encompass such changes and modlflcatlons as fall wlthln the scope of the appended clalms.
,,~',` `~` ' . ' ` `: ' . ' h ~
, BACXGROUND OF l~IE INVENTION
Sophlstlcated alrcraft generally lnclude a welght on gear swltch for actlvatlng and deactlvatlng varlous alrcraft systems and fllght controls dependlng upon whether the alrcraft ls airborne or fully supported by the landlng gear on the ground. In some alrcraft, such as hellcopters, the welght on gear swltch also provldes an indlcatlon to the pllot that the alrcraft ls elther alrborne or on the ground.
Aircraft welght on gear swltches, or squat switches, are typlcally actuated by a maln landlng gear strut when compressed to support the welght of the alrcraft. On hellcopters wlth skid landlng gear systems, paddles or slmllar devlces have been used to actually contact the ground surface upon landlng of the hellcopter. However, swltches deslgned to contact the ground are generally unrellable because of collectlon of dlrt and debris or damage from skld movement and ob~ects on the ground. In addltlon, ground contact swltches can glve erroneous lndlcatlons when the hellcopter ls landlng on uneven terraln.
Other types of hellcopter welght on gear swltches have been based on collectlve stlck posltlon or englne torque. However, these types of swltches generally can be overridden by the pllot so that they can lndlcate the alrcraft ls ~lrborne when it ls actually on the ground.
Another type of welght on gear swltch for skld gear helicopters ls mounted so as to detect deflectlon of a cross tube of the skld landlng gear. Thls placement of the welght on gear swltch overcomes many of the dlsadvantages of the ground contact or collective stlck ~' posltlon swltches. However, swltches mounted to lndlcate deflectlon of the skid gear cross tube requlre perlodlc ad~ustment as a result of repeated cross tube ... ...... .
'~
', ,`~
.''i''"',~' .. .' ~,. ',' '` . : ' '` `
~: :
`~
~ 3 ~ 6 3 ~i~
deflection from normal landlngs and permanent deformation from harder than normal landlngs. Wlthout such periodlc ad~ustment, welght on gear swltches can glve erroneous lndlcatlons that can affect fllght safety.
Therefore, there ls a need for a mountlng assembly for a hellcopter welght on gear swltch that is self-ad~ust1ng both for normal landlng deflection of the skld gear cross tube and for permanent deformation of the cross tube resultlng from hard landlngs.
:
`' ;" ~
1~ . . . ` . :
$33~
SUMMARY OF THE INVENTION
The present lnventlon ls a self-ad~ustlng sllde assembly for an alrcraft welght on gear swltch. A
preferred embodlment of the sllde assembly ls partlcularly ~dapted for mounting a welght on gear swltch to detect the osclllatory deflectlon of a skld landlng gear cross tube on a hellcopter.
A mountlng bracket of the self-ad~ustlng sllde assembly ls mounted to the underslde of the hellcopter fuselage ln close proxlmity to the center of a cross tube of the skld landlng gear. A back plate extends vertlcally downward from the mountlng bracket. A palr of vertlcal clamp plates are attached to the back plate by fastenlng means so as to form a vertlcal channel lS between the clamp plates and a vertlcal groove between each of the clamp plates and the back plate. A sllde member has a T-shaped flange along one edge thereof for slldably mountlng ln the channel and grooves formed by the back plate and the clamp plates. The fastenlng means may be tlghtened or loosened to ad~ust the force necessary to move the sllde member vertlcally ln the channel ~nd grooves.
The sllde member has a generally C-shaped conflguratlon wlth upper and lower arms. The sllde member ls mounted so that the arms extend above and below the cross tube of the hellcopter skld landlng gear. Durlng take-off and landlng, the cross tube of the landlng gear deflects a known dlstance ln the vertlcal dlrectlon. Deflectlon of the cross tube causes lt to contact a top bumper on the upper arm when the hellcopter ls alrborne and to contact a bottom bumper on the lower arm when the weight of the hellcopter ls on the landlng gear. A mlcroswltch ls mounted on the iower arm sc as to extend vertlcally ~ust above the bottom '~'""" ' ~' '' ' ;2~3r bumper. When the hellcopter lands, the mlcroswltch ls actlvated by the cross tube as lt deflects agalnst the bottom bumper. The bottom bumper protects the mlcroswltch from damage by llmitlng the extent of s contact between the cross tube and the mlcroswltch. The top and bottom bumpers of the sllde member are spaced apart to accommodate the normal vertlcal osclllatory deflectlon of the cross tube about a mean positlon durlng take-off and landlng.
Although the mlcroswltch ls mounted on the slide member to detect the normal range of cross tube deflection, repeated landlngs or harder than normal landlngs can cause the cross tube to be temporarlly or permanently deflected from lts orlglnal mean posltlon ;~
lS wlth respect to the hellcopter. However, the sllde -~
assembly of the present lnventlon automatlcally ad~usts the posltlon of the mlcroswltch durlng each take-off and ;
landlng cycle of the hellcopter to correspond to any change ln the mean posltlon of the cross tube. For example, lf the cross tube ls permanently deflected downward durlng a hard landlng, the cross tube contacts the bottom bumper and moves the entlre sllde member downward relatlve to the bracket attached to the -~
fuselage of the hellcopter. Tnus, the mlcroswltch on the lower arm ls moved downward an amount correspondln~
to the permanent deflectlon of the cross tube so that the normal downward deflectlon of the cross tube upon landlng contlnues to actuate the mlcroswltch.
6 2~633~
BRIEF DESCRIPTION OF THE DRAWINGS
For a more complete understandlng of the present lnventlon and for further advantages thereof, reference ls made to the followlng Descrlption of the Preferred s Embodlment taken in con~unctlon wlth the accompanylng Drawlngs, ln whlch:
FIGURE 1 lllustrates the lnstallatlon of the present inventlon on a hellcopter havlng a skld landlng gear system; and FIGURE 2 ls a perspectlve vlew of the self-ad~ustlng sllde assembly of the present lnventlon.
''; ~
7 ~2~3~L
`
DESCRIPTION OF T}IE PREFERRED EMBODIMEN~
FIGURE 1 shows a self-ad~ustlng sllde assembly 10 of the present lnventlon mounted on the underslde of the fuselage of a hellcopter 11. Hellcopter 11 ls equlpped wlth a skld landlng gear assembly 12 lncludlng ~ cross tube 14 attached to hellcopter 11 by mountlng polnts 13.
Sllde assembly 10 ls mounted ln close proxlmlty to the center of the cross tube 14 between mountlng polnts 13 so that vertlcal osclllatory deflectlon of cross tube 14 about a mean posltlon actuates a weight on gear swltch to lndlcate whether hellcopter 11 ls alrborne or on the ground. Assembly 10 should preferzbly be mounted on rear cross tube 14, as excesslve aft cycllc can transfer vlrtually the entlre welght of the hellcopter from front cross tube 14 to rear cross tube 14 when the hellcopter -ls on the ground. A welght on gear swltch mounted to -~
front cross tube 14 ln thls sltuatlon would falsely -~-~
lndlcate that the hellcopter was alrborne. Thls phenomenon, however, ls not normally exhlblted wlth rear cross tube 14 when full forward cycllc is applled, thus maklng the rear cross tube 14 the preferred posltlon for attachment at assembly 10. Whlle two swltches can be used, one on the front and one on the rear cross tube, preferably only one at the rear cross tube ls used.
FIGURE 2 ls a perspectlve vlew of sllde assembly 1 removed from hellcopter 11. Sllde assembly 10 lncludes a mountlng bracket 16 for mountlng sllde assembly lO to the underside of hellcopter 11. A back plate 18 extends vertlcally downward from mountlng bracket 16. Back plate 18 may comprlse an extenslon of mountlng bracket 16 and/or a separate spacer plate 19 attached to mountlng bracket 16. A palr of vertlcal clamp plates 20 --are attached to back plate 18 by a plurallty of fastenlng means 22, such as nuts, bolts, and washers.
8 ~ 3 ~ ~
Clamp plates 20 may be laminated or lnclude multlple plates such as an lnner wear plate 20a and an outer support plate 20b. Clamp plates 20 are attached to back plate 18 so as to provlde a vertlcal channel 21 between clamp plates 20 and a vertlcal groove 23 between each clamp plate 20 and spacer plate 19.
In the preferred embodlment, mountlng bracket 16 and back plate 18 are constructed of metal spacer plate 19 and lnner wear plate 20a ls preferably constructed from a self-lubricatlng plastlc such as Teflon or ~el-F.
Outer wear plate 20b ls preferably constructed of metal.
The use of self-lubrlcatlng plastlcs ~s useful for ease of malntenance. It ls posslble to use metal ln place of plastlc, however, use of metal would requlre malntenance, lubrlcatlon and preferably a cover to prevent contamlnatlon of the surfaces.
A generally C-shaped sllde member 24 has a T-shaped flange 25 along lts vertlcal edge. T-shaped flange 25 ls adapted to be engaged between clamp plates 20 and spacer plate 19 so that sllde member 24 extends through vertlcal channel 21 and flange 25 slides ln grooves 23 between clamp plates 20 and spacer plate 19. Clamp plate 20a and spacer plate 19 should be made of Teflon or a simllar self-lubrlcatlng plastlc materlal havlng a coefflclent of frlctlon that facllltates slldlng movement of sllde member 24 ln grooves 23 between clamp plates 20 and spacer plate 19. ~n order to prevent corroslon, flange 25 should preferably be made of stalnless steel. Other sultable materlals would lnclude <30 Teflon coated or plastlc coated metal parts.
Sllde member 24 has a lower arm 26 that lncludes a swltch mount 27 and a slot 28 for conflnlng a bottom bumper 29. Sllde member 24 also has an upper arm 30 wlth a top bwmper 32. Top bumper 32 may comprlse, for 2 ~ 3 ~ `
~. ~
example, a section of shrlnk tublng formed about upper arm 30.
Sllde member 24 ls mounted so that upper ~rm 30 extends above cross tube 14 and lower arm 26 extends S below cross tube 14. Arms 26 and 30 are deslgned to extend past the landlng edge of cross tube 14 so as to prevent decoupllng from assembly 10 upon deflectlon of the cross tube durlng a run on landlng. A horlzontal sxtenslon of about 1/2 inch beyond the leading edge of the cross tube, which is slzed to incur a vertlcal deflectlon of about 0.5 lnches when welght of the hellcopter ls added to the landlng gear, has been found -~
to be sufflclent for thls purpose ln the current embodlment of assembly 10. The degree of extension of arms 26 and 30 can be of any length sufflclent to prevent decoupllng of the assembly when the cross tube deflects. Preferably, the assembly 10 ls mounted such that back plate 18 ls on the rear slde of the cross tube.
Durlng take-off and landlng, cross tube 14 normally deflects from a lower positlon agalnst bottom bumper 29 when the welght of hellcopter 11 ls fully on skld gear 12, to an upper posltlon agalnst top bumper 32 when hellcopter 11 ls alrborne. A mlcroswltch 34 mounted on swltch mount 27 extends vertlcally sllghtly above bottom bumper 29 so that cross tube 14 actuates mlcroswltch 34 when hellcopter 11 ls fully on skld gear 12 and cross tube 14 ls ln contact wlth bottom bumper 29. Bottom bumper 29 protects mlcroswltch 14 from any hard contact wlth cross tube 14. As wlll be appreclated, the bumpers are spaced to accommodate the normal deflectlon of the cross tube. The swltch mechanlsm should have a sufflclent length of travel for actlvatlon to prevent false slgnals from vlbratlons. Also preferable, the p~. ,..... .. ... : - ........................... - . ~ : , .
,~. ~ : , ' , !.
2 ~ 3 ~ ---~ 10 swltch is spaced apart from the cross tube when there ls no welght on the gear. It has been found that a cross tube, sized to deflect about 0.5 lnches ln the vertlcal dlrectlon when the welght of the hellcopter ls added to the landlng gear, can be usefully employed ln the present lnventlon. A swltch havlng a travel of about 0.125 lnches or more has been found useful ln the present lnvention.
After repeated landlngs or harder than normal landlngs, the mean posltlon of the osclllatory deflectlon of cross tube 14 may become temporarlly or permanently dlsplaced from lts origlnal posltlon wlth respect to mountlng bracket 16. In prlor art welght on gear swltches, excessive deflectlon of cross tube 14 could cause erroneous fllght lndlcatlons affectlng fllght safety unless the posltlon of the welght on gear swltch was manually ad~usted.
Durlng normal take-offs and landings, cross tube 14 exhlbits osclllatory deflectlon between top bumper 32 and bottom bumper 29, and actuates mlcroswltch 34 when ln contact wlth bottom bumper 29. Because sllde member 24 ls slldably mounted between spacer plate 19 and clamp plates 20, any deflectlon of cross tube 14 beyond lts normally establlshed llmlts causes sllde member 24 to sllde so that top bumper 32 and bottom bumper 29 define new llmlts for osclllatory deflectlon of cross tube 14.
For example, lf a harder than normal landlng causes cross tube 14 to deflect, temporarlly or permanently, further from the fuselage of hellcopter 11, cross tube 14 contacts bottom bumper 29 and forces sllde member 24 to sllde downward to the llmlt of the downward deflectlon of cross tube 14. Because microswltch 34 ls -mounted on lower arm 26, lts posltion ls moved downward a dlstance correspondlng to the downward deflectlon of ;: :: ,: . . .
,~ ,~....
",, ' ~ 11 20~6~3~r cross tube 14 agalnst bottom bumper 29. Llkewlse, any upward deflection of cross tube 14 beyond lts normally establlshed llmlt causes cross tube 14 to contact top bumper 32 and move sllde member 24 upward. Thus, mlcroswltch 34 always malntalns approxlmately the same relatlve posltlon with respect to the mean posltlon of the osclllatory deflectlon of cross tube 14 regardless of any permanent deformatlon of cross tube 14. -The pressure between plates 20a and 19 and flange 25 ls regulated by the torque applled to bolts 22. In order to properly compensate for osclllatory deflection of cross tube 14, thls pressure should be such that approxlmately 35 pounds of force ls requlred to move sllde member 24 vertlcally up or down through vertlcal channel 21. Greater or lesser torque can be applled to the bolts to ad~ust the force requlred to move the slide member. The force selected before movement of the sllde member ls allowed can vary and be ad~usted dependlng upon the degree of sensltlvlty deslred, the slze of the hellcopter and the deflectlon characterlstlcs of the cross tube.
Although the present lnventlon has been descrlbed wlth respect to a speclflc embodlment partlcularly adapted for skld gear hellcopters, varlous changes and modlflcatlons may be suggested to one skllled ln the art to adapt the present lnventlon to other landlng gear systems, for example, and lt ls lntended that the present lnventlon encompass such changes and modlflcatlons as fall wlthln the scope of the appended clalms.
,,~',` `~` ' . ' ` `: ' . ' h ~
Claims (10)
1. A slide assembly for mounting a switch to a support, comprising:
a mounting bracket rigidly attached to the support;
a means attached to the switch for slidably connecting the switch to said mounting bracket;
said slidable means responsive to movement of a member oscillating about a mean position, wherein said slidable means maintains the switch at a substantially constant distance from said mean position of said oscillating member as said mean position varies with respect to the support.
a mounting bracket rigidly attached to the support;
a means attached to the switch for slidably connecting the switch to said mounting bracket;
said slidable means responsive to movement of a member oscillating about a mean position, wherein said slidable means maintains the switch at a substantially constant distance from said mean position of said oscillating member as said mean position varies with respect to the support.
2. The slide assembly of Claim 1, wherein said support comprises an aircraft and said oscillating member is connected to a landing gear system of the aircraft.
3. A slide assembly for mounting an aircraft weight on gear switch, comprising:
a mounting bracket rigidly attached to the aircraft;
a means attached to the weight on gear switch for slidably mounting the switch on said mounting bracket;
and said slidable means responsive to oscillatory movement of the aircraft landing gear about a mean position so as to maintain the switch at a substantially constant distance from said mean position.
a mounting bracket rigidly attached to the aircraft;
a means attached to the weight on gear switch for slidably mounting the switch on said mounting bracket;
and said slidable means responsive to oscillatory movement of the aircraft landing gear about a mean position so as to maintain the switch at a substantially constant distance from said mean position.
4. The slide assembly of Claim 3, wherein said slidable means comprises a C-shaped slide member having an upper arm and a lower arm, said upper and lower arms extending, respectively, above and below a component of the aircraft landing gear.
5. The slide assembly of Claim 4, wherein said mounting bracket comprises:
a back plate:
a clamp plate fastened to said back plate to form a channel; and said C-shaped slide member mounted in said channel for slidable movement with respect to said mounting bracket.
a back plate:
a clamp plate fastened to said back plate to form a channel; and said C-shaped slide member mounted in said channel for slidable movement with respect to said mounting bracket.
6. In a helicopter having a weight on gear switch actuated by oscillatory deflection of a landing skid cross tube about a mean position, a slide assembly comprising:
a mounting bracket rigidly attached to the helicopter;
a C-shaped slide member slidably mounted on said mounting bracket;
an upper arm of said slide member extending above the cross tube; and a lower arm of said slide member extending below the cross tube and having the weight on gear switch mounted thereon at a predetermined distance from the mean position of the cross tube.
a mounting bracket rigidly attached to the helicopter;
a C-shaped slide member slidably mounted on said mounting bracket;
an upper arm of said slide member extending above the cross tube; and a lower arm of said slide member extending below the cross tube and having the weight on gear switch mounted thereon at a predetermined distance from the mean position of the cross tube.
7. The slide assembly of Claim 6, wherein said mounting bracket comprises:
a back plate; and a clamp plate fastened to said back plate so as to form a channel for mounting said slide member.
a back plate; and a clamp plate fastened to said back plate so as to form a channel for mounting said slide member.
8. The slide assembly of Claim 7, wherein said C-shaped slide member includes a T-shaped flange along a vertical edge thereof for slidably mounting said slide member in said channel.
9. The slide assembly of Claim 8, wherein said upper and lower arms define approximate upper and lower limits, respectively, of the cross tube oscillatory deflection.
10. The slide assembly of Claim 9, wherein deflection of the cross tube beyond said limits causes said slide member to slide with respect to said mounting bracket so that the weight on gear switch maintains a substantially constant distance from the mean position of the cross tube.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US07/424,291 US5045649A (en) | 1989-10-03 | 1989-10-03 | Self-adjusting slide assembly for weight on gear switch |
| US424,291 | 1989-10-03 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2026331A1 true CA2026331A1 (en) | 1991-04-04 |
Family
ID=23682130
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002026331A Abandoned CA2026331A1 (en) | 1989-10-03 | 1990-09-27 | Self-adjusting slide assembly for weight on gear switch |
Country Status (3)
| Country | Link |
|---|---|
| CA (1) | CA2026331A1 (en) |
| ES (1) | ES2026022A6 (en) |
| IL (1) | IL95878A0 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2033059A2 (en) * | 2006-06-02 | 2009-03-11 | Sikorsky Aircraft Corporation | Surface contact override landing scheme for a fbw rotary-wing aircraft |
-
1990
- 1990-09-27 CA CA002026331A patent/CA2026331A1/en not_active Abandoned
- 1990-10-02 IL IL95878A patent/IL95878A0/en unknown
- 1990-10-03 ES ES9002509A patent/ES2026022A6/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2033059A2 (en) * | 2006-06-02 | 2009-03-11 | Sikorsky Aircraft Corporation | Surface contact override landing scheme for a fbw rotary-wing aircraft |
| EP2033059A4 (en) * | 2006-06-02 | 2013-04-24 | Sikorsky Aircraft Corp | Surface contact override landing scheme for a fbw rotary-wing aircraft |
Also Published As
| Publication number | Publication date |
|---|---|
| ES2026022A6 (en) | 1992-04-01 |
| IL95878A0 (en) | 1991-07-18 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Discontinued |