CA1253815A - Self adjusting parking brake - Google Patents
Self adjusting parking brakeInfo
- Publication number
- CA1253815A CA1253815A CA000484540A CA484540A CA1253815A CA 1253815 A CA1253815 A CA 1253815A CA 000484540 A CA000484540 A CA 000484540A CA 484540 A CA484540 A CA 484540A CA 1253815 A CA1253815 A CA 1253815A
- Authority
- CA
- Canada
- Prior art keywords
- adjusting
- adjusting nut
- strut assembly
- brake
- thrust screw
- 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
- 230000007246 mechanism Effects 0.000 claims abstract description 25
- 230000002093 peripheral effect Effects 0.000 claims abstract description 11
- 230000003213 activating effect Effects 0.000 claims abstract description 6
- 238000013519 translation Methods 0.000 claims abstract description 6
- 230000000694 effects Effects 0.000 claims abstract description 4
- 230000004044 response Effects 0.000 claims abstract description 3
- 230000004323 axial length Effects 0.000 claims description 4
- 230000000717 retained effect Effects 0.000 claims description 3
- 238000004891 communication Methods 0.000 claims description 2
- 230000006854 communication Effects 0.000 claims description 2
- 230000009471 action Effects 0.000 description 5
- 230000004913 activation Effects 0.000 description 5
- 238000001994 activation Methods 0.000 description 5
- 230000000712 assembly Effects 0.000 description 5
- 238000000429 assembly Methods 0.000 description 5
- 238000013461 design Methods 0.000 description 2
- 239000000428 dust Substances 0.000 description 2
- 238000004137 mechanical activation Methods 0.000 description 2
- 230000008859 change Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 229940000425 combination drug Drugs 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 230000013011 mating Effects 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000014616 translation Effects 0.000 description 1
Landscapes
- Braking Arrangements (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
An automatically adjusting automobile parking brake actuating mechanism has a thrust screw attached to a fric-tion pad and axially translated in response to normal brake activating movement of the friction pad. An adjusting nut having an axial threaded bore threadingly receives the thrust screw and includes coaxial ratchet teeth and a peri-pheral groove externally circumscribing the adjusting nut.
An adjuster pawl having a pivot, an adjusting leg communica-ting with the ratchet teeth and a camming leg communicating with the peripheral groove effects pivotal movement of the adjuster pawl, thereby causing rotation of the ratchet teeth and the adjusting nut relative to the thrust screw. An axial force is applied upon the adjusting nut to effect axial translation of the adjusting nut and the thrust screw to urge the friction pad into a brake applying mode.
An automatically adjusting automobile parking brake actuating mechanism has a thrust screw attached to a fric-tion pad and axially translated in response to normal brake activating movement of the friction pad. An adjusting nut having an axial threaded bore threadingly receives the thrust screw and includes coaxial ratchet teeth and a peri-pheral groove externally circumscribing the adjusting nut.
An adjuster pawl having a pivot, an adjusting leg communica-ting with the ratchet teeth and a camming leg communicating with the peripheral groove effects pivotal movement of the adjuster pawl, thereby causing rotation of the ratchet teeth and the adjusting nut relative to the thrust screw. An axial force is applied upon the adjusting nut to effect axial translation of the adjusting nut and the thrust screw to urge the friction pad into a brake applying mode.
Description
B,~
The presen-t invention relates to an improved mechani-cal parking brake actuating assembly, having an integral self-adjusting feature, particularly suitable for use on rear axle disc brake assemblies.
The parking brake actuating assembly~ as taugh-t herein, is a "bolt-on" type assembly intended for external mounting to a disc brake caliper. Use of a "bolt-on"
type assembly eliminates the necessity of having ront and rear axle disc brake assemblies oE different design lQ since the parking brake mechanism is not an integral part of the disc brake assembly.
The present invention provides an automatic brake adjus-ting apparatus comprising, an adjusting strut assembly including adjusting nut means having a threaded bore therein and thrust screw means threadingly received within -the threaded bore, the adjusting nut means having a circumscrib-iny ratchet wheel and a peripheral groove axially separated one from the other, means for attaching the adjusting strut assembly to frif-tion pad means of a brake assembly, whereby the adjusting strut assembly is caused to move in concert with the friction pad means, and pawl means including a firs-t arm communica-tion with -the ratchet wheel and a second arm communicating with the per:Lpheral yroove, the pawl means havLng a pLvot hetween the arms, whereby upon a predeterm:Lned relatlve movernerlt between -the plvot and-the adjust:Lny nut means the fLrst pawl arm i5 caused to ro-tate abou-t the pivot suEficiently -to rotate the ratchet wheel and -the adjus-ting nut means relative to the thrust screw means, thereby changing the axial length of the adjusting strut assembly.
A "bolt-on" self adjusting parking brake assembly according to a preferred embodiment of the inven-tion com-prises an adjustable thrust screw and adjusting nut combina-tion mechanically activated by a toggle pin for parking brake application~ The adjusting nut is ac-ted upon by a ratchet-pawl arrangement each time the thrust screw and adjusting nu-t is activated. Activa-tion of the thrus-t screw ana adjustiny nut combination occurs whenever the parking brake is mechanically activated or whenever the hydraulic brake is activated. Thus adjus-trnent of the parking brake ~ ~ t'~
mechanism, Eor friction pad wear, is maintained reyardless of the frequency of parking brake use.
Figure 1 is an outboard elevati.onal view of a disc brake assembly suitable for use with ~he present mechanical parking brakeO
Figure 2 is a side eleva-tion of the floating caliper disc brake assembly as shown in Figure 1 illustra-ting a "bolt-on" mechanical parking brake assembly as taught herein.
Figure 3 is an inboard elevational view of the disc brake assembly shown in Figures 1 and 2.
Figure 4 is a sectional view taken along line 4 - 4 in Fiyure 3 showing the operating elements of the mechani.cal parking brake ac-tuating assembly.
Figure 5 is a sectional view taken along line 5 - 5 in Figure 4 showing the adjusting pawl mechanism in i-ts idle position~
Figure 6 is a sec-tional view taken along line 6 - 6 in E'igure 5.
Figure 7 is a sec-tional view, similar -to Figure 5 showing the adjustirlg pawl mechanlsm in i.t~ appl:i.ed .state.
E'i.gure 8 J.s an exploded pictorla:L of the "bo:l.t-on"
rl:L~ pa~k~irly br~ s~ b~.y.
F:l.gure na :ls, a subas3embly pictorlal of the adjusting r?aWL mechanism.
The embodimen-t of the present invention which is described herein is preferrably employed in conjunction with a disc brake assembly of a Eloating caliper design such as that shown in United States Paten-t No. 4,391,355. As shown in Figures 1 -through 4 such a brake system generally comprises a C-shaped floating caliper 10 having an inboard leg 2]. and outboard leg 22~ which have affixed thereto brake pad assemblies 16 and 18, respectively. Within inboard leg 21 is cylinder bore 12 having its longi-tudinal axis generally perpendicular to the axis of rotation of disc 20 and having brake act:Lvating p.iston 14 slidably disposed therein. In response to hydraulic activation of the brake, pis-ton 14 ~; exerts a Eorce against inboard brake pad assembly 16 urging the pad into contact wi-th disc 20. In reaction to the force exerted by pad 16 ayalnst rotor 20, caliper 10 translates upon pin 11 such that outboard caliper leg 22 uryes brake pad assembly 18 into contact wi-th the outboard face of rotor 20. As the activating hydraulic pressure increases within bore 12 the clamping force exerted by caliper 10 upon brake pad assemblies 16 and 1~ increases, -thus resulting in increasing braking torques.
With reference to Figures 2,l4 and 8, parkiny brake actuator and adjuster mechanism 24 is mounted to caliper 10 by suitable fastening means such as bolts 23 shown in Figure
The presen-t invention relates to an improved mechani-cal parking brake actuating assembly, having an integral self-adjusting feature, particularly suitable for use on rear axle disc brake assemblies.
The parking brake actuating assembly~ as taugh-t herein, is a "bolt-on" type assembly intended for external mounting to a disc brake caliper. Use of a "bolt-on"
type assembly eliminates the necessity of having ront and rear axle disc brake assemblies oE different design lQ since the parking brake mechanism is not an integral part of the disc brake assembly.
The present invention provides an automatic brake adjus-ting apparatus comprising, an adjusting strut assembly including adjusting nut means having a threaded bore therein and thrust screw means threadingly received within -the threaded bore, the adjusting nut means having a circumscrib-iny ratchet wheel and a peripheral groove axially separated one from the other, means for attaching the adjusting strut assembly to frif-tion pad means of a brake assembly, whereby the adjusting strut assembly is caused to move in concert with the friction pad means, and pawl means including a firs-t arm communica-tion with -the ratchet wheel and a second arm communicating with the per:Lpheral yroove, the pawl means havLng a pLvot hetween the arms, whereby upon a predeterm:Lned relatlve movernerlt between -the plvot and-the adjust:Lny nut means the fLrst pawl arm i5 caused to ro-tate abou-t the pivot suEficiently -to rotate the ratchet wheel and -the adjus-ting nut means relative to the thrust screw means, thereby changing the axial length of the adjusting strut assembly.
A "bolt-on" self adjusting parking brake assembly according to a preferred embodiment of the inven-tion com-prises an adjustable thrust screw and adjusting nut combina-tion mechanically activated by a toggle pin for parking brake application~ The adjusting nut is ac-ted upon by a ratchet-pawl arrangement each time the thrust screw and adjusting nu-t is activated. Activa-tion of the thrus-t screw ana adjustiny nut combination occurs whenever the parking brake is mechanically activated or whenever the hydraulic brake is activated. Thus adjus-trnent of the parking brake ~ ~ t'~
mechanism, Eor friction pad wear, is maintained reyardless of the frequency of parking brake use.
Figure 1 is an outboard elevati.onal view of a disc brake assembly suitable for use with ~he present mechanical parking brakeO
Figure 2 is a side eleva-tion of the floating caliper disc brake assembly as shown in Figure 1 illustra-ting a "bolt-on" mechanical parking brake assembly as taught herein.
Figure 3 is an inboard elevational view of the disc brake assembly shown in Figures 1 and 2.
Figure 4 is a sectional view taken along line 4 - 4 in Fiyure 3 showing the operating elements of the mechani.cal parking brake ac-tuating assembly.
Figure 5 is a sectional view taken along line 5 - 5 in Figure 4 showing the adjusting pawl mechanism in i-ts idle position~
Figure 6 is a sec-tional view taken along line 6 - 6 in E'igure 5.
Figure 7 is a sec-tional view, similar -to Figure 5 showing the adjustirlg pawl mechanlsm in i.t~ appl:i.ed .state.
E'i.gure 8 J.s an exploded pictorla:L of the "bo:l.t-on"
rl:L~ pa~k~irly br~ s~ b~.y.
F:l.gure na :ls, a subas3embly pictorlal of the adjusting r?aWL mechanism.
The embodimen-t of the present invention which is described herein is preferrably employed in conjunction with a disc brake assembly of a Eloating caliper design such as that shown in United States Paten-t No. 4,391,355. As shown in Figures 1 -through 4 such a brake system generally comprises a C-shaped floating caliper 10 having an inboard leg 2]. and outboard leg 22~ which have affixed thereto brake pad assemblies 16 and 18, respectively. Within inboard leg 21 is cylinder bore 12 having its longi-tudinal axis generally perpendicular to the axis of rotation of disc 20 and having brake act:Lvating p.iston 14 slidably disposed therein. In response to hydraulic activation of the brake, pis-ton 14 ~; exerts a Eorce against inboard brake pad assembly 16 urging the pad into contact wi-th disc 20. In reaction to the force exerted by pad 16 ayalnst rotor 20, caliper 10 translates upon pin 11 such that outboard caliper leg 22 uryes brake pad assembly 18 into contact wi-th the outboard face of rotor 20. As the activating hydraulic pressure increases within bore 12 the clamping force exerted by caliper 10 upon brake pad assemblies 16 and 1~ increases, -thus resulting in increasing braking torques.
With reference to Figures 2,l4 and 8, parkiny brake actuator and adjuster mechanism 24 is mounted to caliper 10 by suitable fastening means such as bolts 23 shown in Figure
2. Housing 32 includes intersecting bores 34 and 36. The longitudinal axis of bore 34 is perpendicular to the plane of rotation of disc 20 and is configured to include a first diameter 29 extending from the inboard end of housing 32 and terminating at shoulder 33; a second diameter 31 extends from shoulder 33 to outboard shoulder 35. Extending from shoulder 35 and terminating at the outboard surface of housing 32 is conically shaped bore 25.
Positioned at the ou-tboard end of bore 31 and extend-ing through conical bore 25 i5 toygle pi.n 52 having its head 54 sea-ted upon shoulder 35. Externally attached to toggle pin 52 is mechanical activating lever 26.
ActivatincJ lever 26 compr:lses side arms 27a and 27b ~pacecl part by web 30. 'rhe s:l.de arm~ lnclude kangs 2~a and 28h whlch are rece:Lved ln locator holes 13a and 13b re~pect:Lvely on houslng 32. Web 30 i3 provided with opening 38 receiving therethrouyh the protruding toggle pin 52.
Toggle pin 52 and activating lever 26 are fastened together by bellville washer 43 received in groove 55 on pin 52 and coil spring 15 ex-tending between eye 57 in pin 52 and no-tch 41 on lever 26. Dust boot 90 is provided to prevent entry of dir-t into bore 25. By action of washer 43 and spring 15, tangs 28a and 28b are retained within locating holes 13a and 13b, and toggle pin head 54 is urged into sea-ting employ~
ment with shoulder 35.
, ,,j; ~
,v, ~ ~ r~ , r ~
Ex-tending through housing bore 34 and in-to mating engagement wi-th bore 31 is adjusting nut 42 having a coaxial threaded bore 44 internally therein~ Adjusting nut 42 com-municates with toggle pin 52 by projection 4g on nu-t 42 ex-tending into abutting engagement with recess 56 wi-thin toggle pin head 54~
Adjusting screw 58 threadingly engayes threaded bore 44 in adjusting nut 42 and includes -flared head 60 which is attachingly received within cage 62 attached to inboard brake pad assembly 16. Dust boot 92 is provided to prevent entry of dirt and contamination from entering bore ~9 in housing 32.
Having described the parking brake activation elements the automatic adjusting elemen-ts will now be described.
Positioned wi-thin intersecting bore 36 in abutting engagemen-t with shoulder 37 is the adjusting mechanism foundation plate 76. Plate 76 is provided with pivot post 73. Post 78 may be provided by upsetting plate metal, as shown, to form the post, by insertion of a roll pin or any other known technique. ~djustment pawl 66 is assembled on plate 76, as shown in E'igure 8a, such that pivot post 78 :I.s received in pivot hole 74 with doy leg 71 of pawl 66 extend~
lny throuyh ape:ratllre 84 of plate 66 thereby placing adjust-~5 :I.rlg lcy 70 and track:Lny axm 68 on opposite sicles oE plate66 and yenera:Ll.y parallel thereto. Spring 88 is a-ttached to and ex-tends between tang 86 on plate 76 and tang 72 on pawl 66 thereby biasing adjus-tment leg 70 in -the counter clockwise direction. Plate 76 is axially retained in posi-tion by snap ring 80 and restrained from rotation by anti~ro-tation -tany 75. When positioned within bore 36 plate 76 forrns an opening bounded hy side 82 of plate 76 and the wall of bore 36 throuyh which ratche-t -teeth 47 protrude and en-gage leg 70 of pawl 66; tracking arm 68, in turn, slidingly engages trucking groove 48 on ad~usting nut 42 as shown in Figures 4, 5, and 7.
OPERATION
My inven-tion as disclosed herein has two opera-tional functions. First, and foremost, the mechanism operates as a mechanical parking brake actuator. Secondly, -the mechanism functions as a self-adjus-ting mechanism preventing loss of effectiveness of the parking brake through wear of the friction pads 16 and 17. The self-adjusting mechanism uniquely has two modes of operation; first and most importantly the self-adjusting mechanism operates to adjust for brake pad wear through normal hydraulic braking activation; secondly, the adjusting mechanism operates upon mechanical activation of the parking brake.
Mechanical actuation of the parking brake is initiated by the vehicle operator applying a tensioning force to cable 98 by means of a parking brake mechanical actuating mechanism (not shown). A tensioning force in cable 98 causes actuator lever 26 to pivot about bores 13a and 13b by the receipt of tangs 28 therein. As lever 26 pivots it in turn causes a like pivoting of toggle pin 52 as shown in Figure 7. The pivo-ting action of toggle pin 52 causes axial transla-tion of adjuster nut 42 hav:LncJ adjustex scrcw 58 threadlngly engaged therein, applying a brake actuatLny Eorce upon Lrlhoard brake pad a3sembly 16. Out-board brake pad assembly 18 ls caused to fr:Lctionally en~
gaye d:Lsc 20 through the reactive force imparted to caliper 10. Upon release of the parking brake mechanism (not shown) by the vehicle opercltor, ac-tivating lever 26 and -toggle pin 52 return to their normal idle position (as shown in Figure 4~ by action of return spring 15. Adjusting nut 42 in combination with screw 58 return to their idl~ position by action of spring 88.
During normal hydraulic activation of the disc brake, movement of the inboard brake pad assembly 16 causes a similar axial movement oE the adjusting nu-t 42 and adjusting screw 58 assembly through the engagement and entrapmen-t of screw head 60 within the bracket 62 affixed to -the backing plate of inboard brake pad assembly 16. Any axial movemen-t , -~ of adjus-ting nut 42 toward the disc 20 whether by ac-tuation /J~, ., ,.
81.
~ 6 --of the hydraulic brake or by the mechanical parkiny brake will set in motion the self adjusting mechanism and for a given axial displacement of adjusting nut 42, representing an amount of brake pad wear requiring adjustment, the adjust-ing pawl 66 affects rotation of adjusting nut 42 therebyadvancing adjusting screw 58 a proportional amount as explained below.
Referring primarily to Fi~ures 5, 6, and 7 it is seen that as the adjusting nut 42 is caused to translate toward the disc 20 leg 68 of adjuster pawl 66 tracking within groove 48 of adjuster nut 42 effects pivotal movement of pawl 66 about pivot 78. Compare Figure 5 showing the mechanism in i-ts non-applied state and Figure 7 showing the mechanism in the brake applied s-tate. It should be appreciat-ed that since Figure 7 depicts mechanical activation of the mechanism, toggle pin 52 is shown in its tilted position;
when adjusting nut 42 translates because of hydraulic brake acti~a-tion toggle pin 52 remains in its idle position as shown in Figure 5.
If -the s-tate of the bralce pad assemblies 16 and 18 are such that a wear adjustment of the mechanical brake mechanism is desired, as maniEested in a predeterm:Lned amount oE ad-Juster screw tran~lat.iorl, pawl ratchet lecJ 70 i3 caused to advarlce upon ~juster .screw ratchet wheel 47 engaglny the next avaLlable tooth as seen again by com-paxlny E'igures 5 and 7.
Upon release of the brake applying mechanism (either the parking brake or hydraulic brake~ the energy stored in spring 88, during brake application, acts to res-tore not only pawl 66 to its original position thereby rotating adjuster nut 42 causing a proportional advance of adjuster screw 58 bu-t through action of pawl leg 68 upon adjuster screw groove 48 the adjuster screw 42 is caused to return to its idle position as shown in Figure 2 and 5.
While the above description constitu-tes the pre-ferred embodiment of the invention, it will be appreciated -th~t -the invention is susceptible to modifica-tion, -- varia-tion and change withou-t departing from the scope or fair meaning of -the accompanying claims.
Positioned at the ou-tboard end of bore 31 and extend-ing through conical bore 25 i5 toygle pi.n 52 having its head 54 sea-ted upon shoulder 35. Externally attached to toggle pin 52 is mechanical activating lever 26.
ActivatincJ lever 26 compr:lses side arms 27a and 27b ~pacecl part by web 30. 'rhe s:l.de arm~ lnclude kangs 2~a and 28h whlch are rece:Lved ln locator holes 13a and 13b re~pect:Lvely on houslng 32. Web 30 i3 provided with opening 38 receiving therethrouyh the protruding toggle pin 52.
Toggle pin 52 and activating lever 26 are fastened together by bellville washer 43 received in groove 55 on pin 52 and coil spring 15 ex-tending between eye 57 in pin 52 and no-tch 41 on lever 26. Dust boot 90 is provided to prevent entry of dir-t into bore 25. By action of washer 43 and spring 15, tangs 28a and 28b are retained within locating holes 13a and 13b, and toggle pin head 54 is urged into sea-ting employ~
ment with shoulder 35.
, ,,j; ~
,v, ~ ~ r~ , r ~
Ex-tending through housing bore 34 and in-to mating engagement wi-th bore 31 is adjusting nut 42 having a coaxial threaded bore 44 internally therein~ Adjusting nut 42 com-municates with toggle pin 52 by projection 4g on nu-t 42 ex-tending into abutting engagement with recess 56 wi-thin toggle pin head 54~
Adjusting screw 58 threadingly engayes threaded bore 44 in adjusting nut 42 and includes -flared head 60 which is attachingly received within cage 62 attached to inboard brake pad assembly 16. Dust boot 92 is provided to prevent entry of dirt and contamination from entering bore ~9 in housing 32.
Having described the parking brake activation elements the automatic adjusting elemen-ts will now be described.
Positioned wi-thin intersecting bore 36 in abutting engagemen-t with shoulder 37 is the adjusting mechanism foundation plate 76. Plate 76 is provided with pivot post 73. Post 78 may be provided by upsetting plate metal, as shown, to form the post, by insertion of a roll pin or any other known technique. ~djustment pawl 66 is assembled on plate 76, as shown in E'igure 8a, such that pivot post 78 :I.s received in pivot hole 74 with doy leg 71 of pawl 66 extend~
lny throuyh ape:ratllre 84 of plate 66 thereby placing adjust-~5 :I.rlg lcy 70 and track:Lny axm 68 on opposite sicles oE plate66 and yenera:Ll.y parallel thereto. Spring 88 is a-ttached to and ex-tends between tang 86 on plate 76 and tang 72 on pawl 66 thereby biasing adjus-tment leg 70 in -the counter clockwise direction. Plate 76 is axially retained in posi-tion by snap ring 80 and restrained from rotation by anti~ro-tation -tany 75. When positioned within bore 36 plate 76 forrns an opening bounded hy side 82 of plate 76 and the wall of bore 36 throuyh which ratche-t -teeth 47 protrude and en-gage leg 70 of pawl 66; tracking arm 68, in turn, slidingly engages trucking groove 48 on ad~usting nut 42 as shown in Figures 4, 5, and 7.
OPERATION
My inven-tion as disclosed herein has two opera-tional functions. First, and foremost, the mechanism operates as a mechanical parking brake actuator. Secondly, -the mechanism functions as a self-adjus-ting mechanism preventing loss of effectiveness of the parking brake through wear of the friction pads 16 and 17. The self-adjusting mechanism uniquely has two modes of operation; first and most importantly the self-adjusting mechanism operates to adjust for brake pad wear through normal hydraulic braking activation; secondly, the adjusting mechanism operates upon mechanical activation of the parking brake.
Mechanical actuation of the parking brake is initiated by the vehicle operator applying a tensioning force to cable 98 by means of a parking brake mechanical actuating mechanism (not shown). A tensioning force in cable 98 causes actuator lever 26 to pivot about bores 13a and 13b by the receipt of tangs 28 therein. As lever 26 pivots it in turn causes a like pivoting of toggle pin 52 as shown in Figure 7. The pivo-ting action of toggle pin 52 causes axial transla-tion of adjuster nut 42 hav:LncJ adjustex scrcw 58 threadlngly engaged therein, applying a brake actuatLny Eorce upon Lrlhoard brake pad a3sembly 16. Out-board brake pad assembly 18 ls caused to fr:Lctionally en~
gaye d:Lsc 20 through the reactive force imparted to caliper 10. Upon release of the parking brake mechanism (not shown) by the vehicle opercltor, ac-tivating lever 26 and -toggle pin 52 return to their normal idle position (as shown in Figure 4~ by action of return spring 15. Adjusting nut 42 in combination with screw 58 return to their idl~ position by action of spring 88.
During normal hydraulic activation of the disc brake, movement of the inboard brake pad assembly 16 causes a similar axial movement oE the adjusting nu-t 42 and adjusting screw 58 assembly through the engagement and entrapmen-t of screw head 60 within the bracket 62 affixed to -the backing plate of inboard brake pad assembly 16. Any axial movemen-t , -~ of adjus-ting nut 42 toward the disc 20 whether by ac-tuation /J~, ., ,.
81.
~ 6 --of the hydraulic brake or by the mechanical parkiny brake will set in motion the self adjusting mechanism and for a given axial displacement of adjusting nut 42, representing an amount of brake pad wear requiring adjustment, the adjust-ing pawl 66 affects rotation of adjusting nut 42 therebyadvancing adjusting screw 58 a proportional amount as explained below.
Referring primarily to Fi~ures 5, 6, and 7 it is seen that as the adjusting nut 42 is caused to translate toward the disc 20 leg 68 of adjuster pawl 66 tracking within groove 48 of adjuster nut 42 effects pivotal movement of pawl 66 about pivot 78. Compare Figure 5 showing the mechanism in i-ts non-applied state and Figure 7 showing the mechanism in the brake applied s-tate. It should be appreciat-ed that since Figure 7 depicts mechanical activation of the mechanism, toggle pin 52 is shown in its tilted position;
when adjusting nut 42 translates because of hydraulic brake acti~a-tion toggle pin 52 remains in its idle position as shown in Figure 5.
If -the s-tate of the bralce pad assemblies 16 and 18 are such that a wear adjustment of the mechanical brake mechanism is desired, as maniEested in a predeterm:Lned amount oE ad-Juster screw tran~lat.iorl, pawl ratchet lecJ 70 i3 caused to advarlce upon ~juster .screw ratchet wheel 47 engaglny the next avaLlable tooth as seen again by com-paxlny E'igures 5 and 7.
Upon release of the brake applying mechanism (either the parking brake or hydraulic brake~ the energy stored in spring 88, during brake application, acts to res-tore not only pawl 66 to its original position thereby rotating adjuster nut 42 causing a proportional advance of adjuster screw 58 bu-t through action of pawl leg 68 upon adjuster screw groove 48 the adjuster screw 42 is caused to return to its idle position as shown in Figure 2 and 5.
While the above description constitu-tes the pre-ferred embodiment of the invention, it will be appreciated -th~t -the invention is susceptible to modifica-tion, -- varia-tion and change withou-t departing from the scope or fair meaning of -the accompanying claims.
Claims (6)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An automatically adjusting parking brake actuating mechanism for use with an automotive brake assembly com-prising:
thrust screw means attached to friction pad means whereby said thrust screw axially translates in response to normal brake activating movement of said friction pad means;
adjusting nut means having an axial threaded bore threadingly receiving therein said thrust screw, said adjust-ing nut means including coaxial ratchet teeth and a peri-pheral groove externally circumscribing said adjusting nut means;
adjuster pawl means having a pivot, relative to said adjusting nut means, and including an adjusting leg communicating with said ratchet teeth and a camming leg communicating with said peripheral groove whereby axial translation of said adjusting nut means effects pivotal movement of said adjuster pawl means, thereby causing rotation of said ratchet teeth and said adjusting nut means relative to said thrust screw means; and means for applying an axial force upon said adjust-ing nut means thereby effecting axial translation of said adjusting nut means in combination with said thrust screw means to urge said friction pad means into a brake applying mode.
thrust screw means attached to friction pad means whereby said thrust screw axially translates in response to normal brake activating movement of said friction pad means;
adjusting nut means having an axial threaded bore threadingly receiving therein said thrust screw, said adjust-ing nut means including coaxial ratchet teeth and a peri-pheral groove externally circumscribing said adjusting nut means;
adjuster pawl means having a pivot, relative to said adjusting nut means, and including an adjusting leg communicating with said ratchet teeth and a camming leg communicating with said peripheral groove whereby axial translation of said adjusting nut means effects pivotal movement of said adjuster pawl means, thereby causing rotation of said ratchet teeth and said adjusting nut means relative to said thrust screw means; and means for applying an axial force upon said adjust-ing nut means thereby effecting axial translation of said adjusting nut means in combination with said thrust screw means to urge said friction pad means into a brake applying mode.
2. The mechanical parking brake actuating mechanism as claimed in Claim 1 wherein said means for applying an axial force upon said adjusting nut means comprises toggle pin means communicating with said adjusting nut means, whereby pivotal movement of said toggle pin means applies said axial force upon said adjusting nut means.
3. In combination with an automotive hydraulically-activated disc brake, an automatically adjusting parking brake mechanism comprising:
a housing juxtaposed to said disc brake assembly, said housing having an elongate bore extending through said housing;
a parking brake adjusting strut assembly including an elongate adjusting nut having a threaded bore therein and a thrust screw threadingly received within said threaded bore, said adjusting nut having a circumscribing ratchet wheel and peripheral groove axially separated one from the other, said strut assembly slidingly retained within said housing bore, whereby said thrust screw extends from a first open end of said housing bore;
means for attaching said thrust screw to one friction pad assembly of said disc brake, whereby said ad-justing strut assembly is caused to -translate within said elongate bore and in concert with said friction pad assembly;
pawl means movingly affixed to said housing, said pawl means including an adjusting leg communicating with said ratchet wheel and a camming leg communicating with said peripheral groove circumscribing said adjusting nut, whereby translation of said adjuster strut assembly through a predetermined distance causes said pawl means adjusting leg to rotate said ratchet wheel, thereby advancing said adjuster screw outwardly from said adjusting nut -threaded bore thereby increasing the axial length of the adjusting strut assembly; and means for applying an axial force upon said adjust-ing strut assembly, thereby activating said disc brake.
a housing juxtaposed to said disc brake assembly, said housing having an elongate bore extending through said housing;
a parking brake adjusting strut assembly including an elongate adjusting nut having a threaded bore therein and a thrust screw threadingly received within said threaded bore, said adjusting nut having a circumscribing ratchet wheel and peripheral groove axially separated one from the other, said strut assembly slidingly retained within said housing bore, whereby said thrust screw extends from a first open end of said housing bore;
means for attaching said thrust screw to one friction pad assembly of said disc brake, whereby said ad-justing strut assembly is caused to -translate within said elongate bore and in concert with said friction pad assembly;
pawl means movingly affixed to said housing, said pawl means including an adjusting leg communicating with said ratchet wheel and a camming leg communicating with said peripheral groove circumscribing said adjusting nut, whereby translation of said adjuster strut assembly through a predetermined distance causes said pawl means adjusting leg to rotate said ratchet wheel, thereby advancing said adjuster screw outwardly from said adjusting nut -threaded bore thereby increasing the axial length of the adjusting strut assembly; and means for applying an axial force upon said adjust-ing strut assembly, thereby activating said disc brake.
4. The automatically adjusting parking brake mechanism as claimed in Claim 3 wherein said means for applying an axial force upon said adjusting strut assembly comprises toggle pin means in communication with said adjusting strut assembly, whereby pivotal movement of said toggle pin means applies said axial force upon said adjusting strut assembly.
5. Automatic brake adjusting apparatus comprising:
an adjusting strut assembly including adjusting nut means having a threaded bore therein and thrust screw means threadingly received within said threaded bore, said adjusting nut means having a circumscribing ratchet wheel and a peripheral groove axially separated one from the other;
means for attaching said adjusting strut assembly to friction pad means of a brake assembly whereby said adjusting strut assembly is caused to move in concert with said friction pad means;
pawl means including a first arm communicating with said ratchet wheel, a second arm communicating with said peripheral groove and having a pivot therebetween whereby upon a predetermined axial translation of said adjusting strut assembly said adjusting strut assembly causes rotational movement of said pawl arms about said pivot sufficient to rotate said ratchet wheel and said adjusting nut means relative to said thrust screw means, thereby changing the axial length of said adjusting strut assembly.
an adjusting strut assembly including adjusting nut means having a threaded bore therein and thrust screw means threadingly received within said threaded bore, said adjusting nut means having a circumscribing ratchet wheel and a peripheral groove axially separated one from the other;
means for attaching said adjusting strut assembly to friction pad means of a brake assembly whereby said adjusting strut assembly is caused to move in concert with said friction pad means;
pawl means including a first arm communicating with said ratchet wheel, a second arm communicating with said peripheral groove and having a pivot therebetween whereby upon a predetermined axial translation of said adjusting strut assembly said adjusting strut assembly causes rotational movement of said pawl arms about said pivot sufficient to rotate said ratchet wheel and said adjusting nut means relative to said thrust screw means, thereby changing the axial length of said adjusting strut assembly.
6. Automatic brake adjusting apparatus comprising:
an adjusting strut assembly including adjusting nut means having a threaded bore therein and thrust screw means threadingly received within said threaded bore, said adjusting nut means having a circumscribing ratchet wheel and a peripheral groove axially separated one from the other;
means for attaching said adjusting strut assembly to friction pad means of a brake assembly, whereby said adjusting strut assembly is caused to move in concert with said friction pad means;
pawl means including a first arm communicating with said ratchet wheel, a second arm communicating with said peripheral groove and having a pivot therebetween whereby upon a predetermined relative movement between said pivot and said adjusting nut means said first pawl arm is caused to rotate about said pivot sufficiently to rotate said ratchet wheel and said adjusting nut means relative to said thrust screw means, thereby changing the axial length of said adjusting strut assembly.
an adjusting strut assembly including adjusting nut means having a threaded bore therein and thrust screw means threadingly received within said threaded bore, said adjusting nut means having a circumscribing ratchet wheel and a peripheral groove axially separated one from the other;
means for attaching said adjusting strut assembly to friction pad means of a brake assembly, whereby said adjusting strut assembly is caused to move in concert with said friction pad means;
pawl means including a first arm communicating with said ratchet wheel, a second arm communicating with said peripheral groove and having a pivot therebetween whereby upon a predetermined relative movement between said pivot and said adjusting nut means said first pawl arm is caused to rotate about said pivot sufficiently to rotate said ratchet wheel and said adjusting nut means relative to said thrust screw means, thereby changing the axial length of said adjusting strut assembly.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000484540A CA1253815A (en) | 1985-06-19 | 1985-06-19 | Self adjusting parking brake |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000484540A CA1253815A (en) | 1985-06-19 | 1985-06-19 | Self adjusting parking brake |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1253815A true CA1253815A (en) | 1989-05-09 |
Family
ID=4130764
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000484540A Expired CA1253815A (en) | 1985-06-19 | 1985-06-19 | Self adjusting parking brake |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1253815A (en) |
-
1985
- 1985-06-19 CA CA000484540A patent/CA1253815A/en not_active Expired
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US6293370B1 (en) | Vehicle brake having electric motor control of brake running clearance | |
| KR100287488B1 (en) | Brake lever of vehicle drum brake | |
| US8011482B2 (en) | Electric actuator unit for a vehicle brake assembly | |
| US5823636A (en) | Vehicle braking system | |
| US5070968A (en) | Leading/trailing drum brake having servo parking brake | |
| US5322145A (en) | Drum brake operating mechanism | |
| EP0260934B1 (en) | Disc brakes | |
| CA2131163A1 (en) | Trailer brake system with release apparatus | |
| US6715588B2 (en) | Spot type disc brake with parking brake function | |
| US5000298A (en) | Brake beam | |
| EP0789156B1 (en) | Brake condition monitoring means | |
| US4540066A (en) | Self-adjusting parking brake | |
| US5062506A (en) | Rotary drum brake assembly bracket | |
| CA1253815A (en) | Self adjusting parking brake | |
| US4553643A (en) | Disc brake for trucks | |
| GB2155126A (en) | Disc brake adjustors | |
| EP0125487B1 (en) | Slack adjuster for a disc brake | |
| US5520068A (en) | Brake arrangement and compensating roller | |
| GB2177171A (en) | Automatic adjusting; disc brakes; parking brake | |
| US20090071768A1 (en) | Mechanical Disc Braking Assembly | |
| US5480010A (en) | Drum brake adjuster | |
| CA1144489A (en) | Drum brake adjuster | |
| US6206148B1 (en) | Drum brake with duo-actuation | |
| EP0116501B1 (en) | Brake adjusting screw and clip assembly | |
| EP0237158A1 (en) | Improvements in self-energising disc brakes |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |