WO1982003667A1

WO1982003667A1 - Disc brake

Info

Publication number: WO1982003667A1
Application number: PCT/SE1982/000090
Authority: WO
Inventors: Components Ab Itera
Original assignee: Olsson Jan Gustaf; Samuelsson Lars Erik; Samuelsson Karl Erik; Ekblad Gunnar; Javer Ingvar
Priority date: 1981-04-10
Filing date: 1982-03-26
Publication date: 1982-10-28
Also published as: JPS58500620A; IT8283356A0; ES511251A0; EP0076290A1; ES8305475A1

Abstract

A brake of disc brake type with at least one brake block, which is non-rotatably supported and can be pressed against a rotating brake disc. In this connection a brake disc is a denomination comprising any rotating element with a substantially axially directed friction surface, against which a brake block is actuating. The brake surface can also exhibit a conical shape. It is an object of the invention to provide a safe braking means of simple construction preferably with a servo effect and fit for universal use at the same time as it is well suited for application in connection with bicycles and similar vehicles. According to the invention the brake block (5) is supported by a support (6) extending along the friction surface of the brake disc (2), said support being supported in a bearing (8), which for one thing is movable away from and towards the friction surface of the brake disc and for another thing is displaceable relative to the support along said friction surface against bias of a yielding force, the bearing being adapted to the effect that said movement in direction towards the friction surface of the brake disc is obtained by force, when the brake block with the support belonging to the same is displaced along the friction surface against bias of said yielding force, which tends to return the support with its brake block to its starting position.

Description

Disc Brake

The present invention relates to a disc brake of the kind exhibiting at least one not'rotatably supported brake block, which can be pressed against a ro¬ tating brake disc. It is possible to imagine a great number of applications of the invention to operations involving th braking of a rotating element. In such connection a rotatin element can suitably exhibit a friction surface rotating wi said element and preferably facing in^" an essentially axial direction, upon which surface at least one brake block is actuating. Two such braking surfaces can suitably be formed by the lateral sides of a brake disc facing away from each other. The invention is in the first place intended to be applied to vehicles, although it is not limited thereto. Especially great advantages can be realized by means of the invention in connection with two-wheeled vehicles, such as motor cycles and bicycles.

It is a principal object of the invention to provide a brake of the kind mentioned above, that is of simp le construction and consequently with a low manufacturing cost, easy to mount, reliable in operation and in spite of its simple design exhibits an efficient braking action pre¬ ferably with servo effect without any risk of getting locked

Said object is obtained by means of a brake designed according to the invention, which is substantially characterized by the brake block being supported by a suppor ing element extending along the friction surface of the brak disc, said supporting element being mounted in a bearing mea which for one thing permits a movement away from and towards the friction surface of the brake disc and for another thing permits its displacement relative to said supporting element along said friction surface against the bias of a yielding force, the bearing means being adapted to the effect that said movement in direction towards the friction surface of the brake disc being obtained by force, when the brake block with its supporting element is displaced along the fric¬ tion surface against bias of said yielding force, which tends to bring back the supporting element with its brake block to its starting position. The invention will be described in the follo ing, reference ^'being made to the accompanying drawings, in which

Fig. 1 is a perspective view of a brake made according to a first example of embodiment of the invention, said brake being mounted on the front fork portion of a bi¬ cycle, the wheel of said cycle for clarity's sake not being shown, and only one leg of the front fork appearing in the illustration.

Fig. 2 is a partly sectional top view of the same brake in its resting position.

Fig. 3 is a top view corresponding to the on in Fig. 2 and showing the brake in its activated position.

Fig. 4 is a partly sectional perspective vie of a disc brake according to an example of embodiment of a further, developed version of the same.

Fig. 5 is a central sectional view taken in the direction of the arrows II-III in Fig. 4 illustrating the brake in its resting position.

Fig. 6 is a sectional view of the brake corre sponding to the version shown in Fig. 5 and showing the same in .braking position.

Fig. 7 is a sectional view taken along the line IV-V in Fig. 4 showing the brake in resting position.

Fig. 8 is a sectional view of the brake corre sponding to the version shown in Fig. 7 and showing the same in braking position, and

Fig. 9 is a sectional perspective view of a disc brake made according to an additional example of embodi ment of the invention and corresponding to the view shown in Fig. 4.

OMPI IPO As regards the Figs. 1-3 a brake disc 2 is mounted on the shaft 1 of the front wheel, not shown, of a bicycle, in such a manner, that it rotates together with said shaft 1. The shaft 1 and the brake disc 2 are held in place at the lower end of the leg of the front fork 4 by means of a nut lock 3. The bicycle suitably also exhibits a second front fork leg located on the opposite side of the front wheel of the bicycle, but as the invention does not directly involve this fork leg, it is not shown in the draw- ings. It is of course possible to apply the invention to such pedal operated bicycles, light weight or heavy weight motorcycles as exhibit only one front fork leg, i.e. where the wheel exhibits a single bearing suspension. Two brake blocks 5 arranged each one on its side of the brake disc 2 near to the periphery of the same are supported by each other facing sides of two long brake block supports 6, which are designed in the form of long bars, which, when the brake blocks bear against the brake disc, form double- armed levers with a pivoting point somewhere within the range of the brake blocks 5. The direction of rotation of the brake disc and the bicycle wheel is indicated with an arrow 7 in each one of the drawings. The front arms of the brake .block supports are indicated with 6a, and their rear arms are in¬ dicated with 6b. The front arms 6a penetrate into a hood- shaped bearing element 8, which suitably exhibits upper and lower guide surfaces 8a, which are vertically interspaced in such a manner that they form a free passage for the arms 6a penetrating into the bearing element 8, but at the same time keep them upwards guided in such a way that the brake block supports do not need any special suspension outside the bear¬ ing element 8; The brake block supports are made in the form of flat plate-shaped elements extending substantially parallel to the brake disc. The front end of the brake block supports is designed with a thick portion 6c, which can either comp- rise a separate roller body or be an integrated part of t e brake block supports. These thick portions 6c rest each one against its guiding and sliding surface 9 of the bearing element 8. The sliding surfaces 9 occupy an oblique posi¬ tion relative^' to the bearing surfaces of the brake disc at a suitable angle -*- , so that in the direction of rota- tion, i.e. in the direction of the arrow 7, said sliding surfaces 9 converge towards the friction surfaces of the brake disc. A return spring 10 of pressure type is inserted between a front stop surface 8b and each one of the brake block supports. In the rear direction the sliding surfaces blend into stop formations 11 shaped in the bearing element 8 and preventing the .brake block supports to be dislocated out of the bearing element 8. The hood formed by the bearing element 8 is suitably closed in its upper portion and open at its bottom portion in order to permit particles of dirt to fall down out of the same, so that they do not accumulate in its hollow space 12. The bearing element 8 is supported by an arm 13 extending between said bearing element and the front fork leg 4 of the bicycle, said arm 13 at its front end as well as at its rear end exhibiting an adjustable bearing 14 and 15 respectively, each of which can suitably exhibit friction surfaces, which can be tightened against each other. Thus, a setting of the angular position of the arm relative to the front fork leg as well as relative to the bearing element 8 is permitted. In this manner the po- sition of the bearing element 8 and consequently also the positio of the brake blocks 5 relative to the^' brake disc can be adjusted in an efficient manner. After tightening the terminal bearings 14, 15 the position of the bearing element 8 is thus fixed relative to the brake disc and the front fork leg 4. An operating wire 16 suitably extends to the cycle grip of the cycle handle bar (not shown in the drawings) but can of course also be imagined to extend unto the pedal system of the bicycle in order to be actuated from there. The end of the wire 16 is by means of a stop and fixing means 17 connected with the rear arm 6b of the brake block support illustrated to the left in Figs. 2 and 3. A casing 18 encloses the operating wire and is by means of an adjustable actuating portion 19 connected with the rear arm 6b of the brake block support, which in the Figs. 2 and 3 is shown to. the right. A return spring 20 of press- ure type is inserted between the respective arms 6b of the two brake block supports and constantly tends to move the arms 6b in direction away from each other and, thus, also to move the brake blocks 5 out of engagement with the brake disc. When a braking operation is taking place, the operating wire 16 is pulled in the direction of the arrow 21 relative to the casing 18. The two arms 6b are then pressed against each other in the direction of the arrows 22 in Fig. 3 against bias of the return spring 20, while the arms 6 pivot at their thick end portions 6c. This pivoting movement continues until the brake blocks 5 reach contact with the rotating brake disc 2. On account of the friction forces arising between the brake disc and the brake blocks 5 the brake blocks and consequently also the brake block supports 6 are carried along in the rotating movement of the brake disc against bias of the pressure springs 10, while the thick end portions 6c slide in forwards direction along their respective sliding paths 9. Thus, on account of the wedge angle <= * between the sliding paths 9 and the brake disc .the front ends of the brake block supports are by force caused to approach .the friction surfaces of the brake disc. An augmentation of the braking force, i.e. a so called servo effect, is thereby obtained, as long as the operating^" w^"ire^~ 16 is maintained in its stretched activating position. When the wire 16 is slackened, the return spring 20 brings the arms 6b to move in direction away from each other, whereby the contact of the brake blocks 5 against the brake disc ceases, which in its turn by action of the return springs 10 brings about an immediate return of the brake block supports to their starting and resting position shown in Fig. 2. Thus, there does not exist any risk of the brake blocks being locked in their activated position, i.e. in a position, in which they are kept pressed against the brake disc in the direct¬ ion of the arrows 22 in Fig. 3.

In the embodiment described above the wire 16 with its connecting portions as well as the bearing ele¬ ment 8 bridge the periphery of the brake disc, while the other portions of the brake extend inside of the periphery of the brake disc. An embodiment can of course also be ima¬ gined, in which the brake system is halved, i.e. it lacks one brake block and the corresponding brake block support. In this case also the brake^' disc of course exhibits only one friction surface.

The thick end portions can also be designed in the form of loose pins, which in connection with their mounting can be introduced into the bearing element 8 throug holes taken out on the top side of the same for engagement with the end portions of the brake block supports, when they have been inserted into the bearing element 8 against bias of the pressure springs 10. By means of this arrangement a very simple mounting operation is obtained.

Although the transmission of the force of application of the brake has been shown to take place by means of a wire, also another type of power transmission can be imagined, such as by way of example a hydraulic or pneumatic transmission. This is especially convenient in connection with heavy vehicles.

The bearing element can of course also be mounted in the reverse order, i.e. the brake block supports can extend from the same in the direction of rotation of the brake disc. Instead of the illustrated horizontal mounting a vertical mounting or any other mounting in any suitable direction can be imagined. The brake blocks can also be straight instead of exhibiting the illustrated bent shape.

A downwards open be11-shaped brake yoke, which in the Figs. 4-8 of the drawings is indicated with 101, in its each other opposing wall portions at the bottom exhibits a slit 102, the width of which somewhat exceeds the thick¬ ness of the brake disc 103, which is illustrated with con¬ tinuous lines in Figs. 5-8 but only hinted with dashed and dotted lines in Fig. 4. The brake yoke 101 thus straddles the brake disc and hangs downwards over its periphery on both of its sides. On one side the brake yoke exhibits a projection 104, which. is provided with fastening holes 105 designed to be penetrated by bolts for the fastening of the brake yoke by way of example to the frame of the vehicle, on which the brake shall be used, or in the wheel under¬ carriage or similar, which supports the brake disc 103. When the brake disc is resiliently suspended relative to the other parts of the vehicle, the brake yoke must follow along in the movement of the same. The brake yoke' 101 must therefore be fastened to the part of the vehicle, which is carried along with the brake disc in these movements. The brake yoke illustrated in the drawings exhibits the shape of a polygon, but within the scope of the invention it can exhibit any exterior shape. The brake yoke having the form of a casing exhibits an upper endwall portion 101a, a por¬ tion 101b connected thereto and of the shape of a frustrum of a cone and a bottom portion 101c with substantially ver¬ tical walls, which in its turn connects to said portion 101 The cavity in the upper portion 101b can suitably be of cir cular shape or in downwards direction blend into an oval cavity, which extends in the plane of the brake disc 103. Two brake blocks located each one on its side of the brake disc are indicated with 106, each one on its side facing the brake disc supporting a brake lining 107. The brake blocks 106 exhibit a curved outer surface, which along a vertical line bears against the inside of the lower portion of the brake yoke. In the embodiment illustrated in the drawings the outside of the brake blocks exhibits a curvature of a smaller radius than the one of the inner wall lOld of the brake yoke. Outside of the periphery of the brake disc the brake blocks exhibit vertically projecting necks 108, which via pivoting links 109 are connected with a central draw • bar 110. The pivoting links 109 are pivotably connected with the draw bar by means of a pivot pin 111 and with the brake blocks by means of a pivot pin 112. Outside of the periphery of the brake disc there is likewise inserted a pressure spring 113 between the two brake blocks, which pressure spring tends to keep the brake blocks pressed against the inside of the brake yoke thereby keeping them free from contact with the brake disc. Pressure springs 114 are moreover inserted between the inside of the wall of the brake yoke and the necks of the brake blocks; which pressure springs actuate against each other and against each other opposing sides of the necks, so that they tend to keep the brake blocks in a central and neutral position as counted along the plane of the brake disc. Because of the fact that the inside lOld of the brake yoke is of curve shape the brake blocks are permitted to perform an oscillat ing movement along the plane of the brake disc, while as a consequence of their sliding movement against the inside of the brake yoke they are pressed against the brake disc in their extreme oscillating positions against bias of the pressure springs 114 and the pressure spring 113. An operat ing wire 115 is connected with the draw bar 110 and is in its bottom end portion suitably provided with a ferrule, which can be adjusted by means of a screw and which engages the draw bar 110, so that the length of the wire can be ad¬ justed. The wire casing 116 is -further held by means of a screw fitting 117 at a spherical bearing 118, which rests in a spherically shaped cavity 119 in the end wall 101a of the brake yoke. A pressure spring 120 rests with one end against the end wall of the brake yoke and with its other end against the brake blocks. The pressure spring 120 thus tends to move the brake blocks in downwards direction. When there is no pull in the wire 115 the pressure spring 120 keeps the brake blocks in their low position, which is best evident from Fig. 5. As the brake yoke widens in downwards^'

OMPI direction, the brake blocks with their brake lining are free from contact with the brake disc 103. In Fig. 5 it is also shown how the pressure spring 113 keeps the brake blocks in bearing contact against the inner wall of the brake yoke and consequently pressed in direction away from the brake disc 103. The two pressure springs 114, which actuate against each other, also keep the brake blocks in a central and neutral position as counted along the plane of the brake disc, as is best evident from Fig-. 7, in which figure the pressure springs 114 are not shown for simplici¬ ty's sake. In connection with a pull in the wire 115 the brake blocks are brought in upwards direction against bias of the pressure spring 120. By the conical guiding surfaces formed by the outer sides of the brake blocks and the in- side of the brake yoke the brake blocks are then brought into bearing contact against the brake disc 103 against bias of the pressure spring 113, as is shown in Fig. 6. When the brake blocks reach contact with the brake disc, they are carried along against the brake disc in the direct ion of rotation of the latter one as a consequence of the friction force, said direction of rotation being indicated with the arrow 121 in Figs. 7 and 8. The brake blocks are thereby also brought to slide against the inside of the yok in the direction of rotation of the brake disc, and because of the movement of the brake disc they will get still tight pressed against the same. In this manner a servo effect is produced. This sideways displaced oscillating position of the brake blocks is evident from Fig. 8. The brake blocks may possibly be arranged in such a manner that in connec- tion with a pull in the wire 115 they will get a somewhat tilting movement relative to the inner wall of the yoke. This might contribute to the brake blocks immediately re¬ leasing their engagement with the brake disc, as soon as the pulling force in the wire 115 ceases, and by such an arrange ent any possible tendencies of locking should be entirely eliminated. When the pull in the wire 115 ceases, the press- ure springs 113, 114 and 120 thus bring the brake blocks again to occupy their neutral position, which is shown in Figs. 5 and 7, i.e. their position, in which they are free from contact with the brake disc. In the embodiment illustrated in Fig. 9 the brake yoke comprises a web portion 230 for the mounting on the vehicle of the yoke, which in its entirety is indicated with 234, in the same manner as has been described in con¬ nection with the Figs. 4-8. In Fig. 9 the brake disc hinted with dashed and dotted lines is also indicated with 203.

The bottom projection 232 and the web portion 230 are pro¬ vided with a slit 235 in their low portion, as was also the case in the preceding example, the width of said slit ex¬ ceeding the thickness of the brake disc, which it straddles In this embodiment the brake blocks 236 can only move in th radial direction of the brake disc, and they can therefore not perform any oscillating movement. The brake blocks with^' their brake linings 237 extend through a cavity 246, which is radial relative to the brake disc and located in the bottom projection 232, and emerge out thereof with necks 238, which in their upper portion extend through a cavity in the top projection, said necks by means of a pivot pin 239 being fastened to an operating arm 240, which in its turn is pivoted on the upper projection by means of a pivot pin 241 and thus forms a single arm lever, to one end of which a pulling wire for example can be attached in the fas ening opening indicated with 242. The cavity 246, through which the brake blocks extend,, exhibits a substantially .rec tangular cross-section substantially corresponding to the rectangular cross-section of the brake blocks. The cavity

246 widens in a wedge-like form in downwards direction, and the brake blocks 236 exhibit the corresponding wedge shape. The brake blocks exhibit above the projection 232 a shoulde 243 in the transition section to their shank 238. A spring 244 rests with one end against the shoulders 243 of the brake blocks and with its other end against the underside o

OMPI the upper projection 231. The pressure spring 244 thus tends to move the brake blocks in downwards direction into the position, in which they are not in contact with the brake disc. This embodiment is simplified relative to. the embodiment described above, as in this latter case one does not obtain any servo effect of the brake. In order to facilitate among other things the machining of the cavity 246 the brake yoke 230-232 is made in two preferably sym¬ metric halves, the division plane of which is indicated with 245. In order to protect the brake yoke and its parts against humidity and dirt from above it can suitably be covered by a protective cover. In the embodiment shown in Figs. 4-8 such a protective cover is indicated with 222. The cover 222 protects the ball suspension 218 against dirt which secures the movement of said suspension during the oscillation of the brake blocks 236 along the plane of the brake disc.

In both of the embodiments the mounting of the brake blocks and the parts belonging to them can take place in a simple manner by inserting them in ready mounted condition into the brake yoke from the open side of the same.

The disc brakes described above can as a matter of course be used for the braking of any rotating element. Thus, the invention is not limited to vehicles but can be used in connection also with other rotating machine elements, the movement of which can be braked by means^' of a disc brake. It is not either necessary that the brake force is transmitted in a mechanical way, as is the case with the examples described, but the braking force can by way of example also be hydraulically or pneumatically trans¬ mitted. Although the drawings show that the brake blocks are vertically suspended, the yoke can of course be imagined to be mounted in other positions. Although the denomination "brake disc" has been used in the description of the invention and in the following claims, it should be understood that this ex¬ pression is intended to comprise each embodiment, where one brings a brake block to actuate against a rotating friction surface, which is substantially radially turned. 5 Thus, it is ηot either necessary that this surface shall be completely axially directed, but also a certain conical shape of the friction surface might be imagined without therefore departing from the fundamental idea of the in¬ vention. Also in other respects the invention can be varied m within the scope of the follwing claims without therefore departing from this fundamental idea. Thus, also for exampl wedge-shaped sliding surfaces corresponding to the sliding surfaces 9 can be arranged in opposite direction, i.e. con¬ verge towards the rotating brake surface as counted in the

3-5 rear direction, so that a servo effect also will be obtaine in the reverse direction of rotation.

OMPI

Claims

C l a i m s

1. Disc brake with at least one brake block

(5; 107; -237), which is non-rotatably supported and can be pressed against a rotating brake disc (2; 103; 203), c h a r a c t e r i z e d b y the brake block (5; 107; 237) being supported by a support (6; 106; 236) extending along the friction surface of the brake disc (2; 103; 203), which support is supported in a bearing (8; 101; 231) for one thing in a movable manner away from and towards the friction surface of the brake disc, and for another thing in a displaceable manner relative to the support along said friction surface against bias of a yielding force, the bear ing being adjusted to the effect that said movement in dire tion towards the friction surface of the brake disc is ob¬ tained by force, when the brake block with the support be- longing to the same is displaced along the friction surface against bias of said yielding force, which tends to return the support with its brake block to its starting position.

2. ^" Disc brake according to claim 1, c h a r a c t e r i z e d b y the bearing (8; 101; 231) exhibiting a guiding means (9; lOld; 246) cooperating with the brake blo support (6; 106; 236) with a path of movement converging to wards the rotating brake surface as counted in the directio of rotation of the same.

3. Disc brake according to claim 1 or 2, c h a r a c t e r i z e d b - the brake block support (6;

106; 236) being designed as a lever extending along the brak surface with an arm (6b; 108; 238) extending outside of the brake block as counted along the friction surface of the brake, power means (16, 18; 115, 116; 240) being coupled to said arm (6b; 108; 238) in order to bring the brake block (5; 107; 237) into bearing contact against the rotating brake surface.

OMPI

4. Disc,brake according to claim 3, c h a r a c t e r i z e d b y said brake block supports (6; 106; 236) with the brake blocks (5; 107; 237) belonging thereto ex¬ hibiting a pairwise arrangement, i.e. one on each one of each other opposing sides of the brake disc (2; 103; 203), the power means (16, 18; 115, 116; 240) for the bearing con tact of the brake blocks actuating between the respective right in front of each other positioned lever arms (6b; 108; 238) , whereby the bearing contact takes place by means of a clamping movement of the arms in direction towards each other.

5. Disc brake according to anyone of the preced ing claims, c h a r a c t e r i z e d b y the bearing (8; 101; 231) enclosing a pressure spring (10; 120; 244), which is actuating upon the brake block supports (6; 106; 236) an provides said yielding force, the bearing being supported i one of the structural elements (4) of the vehicle and the brake blocks being supported by said bearing.

6. Disc brake according to anyone of the claims 1-5, c h a r a c t e r i z e d b y the power means actuat ing between the lever arms (6b; 108; 238), which form the brake block supports (6; 106; 236), comprising a pulling wire (16; 115) with its casing (18; 116), a return spring

(20; 113) of pressure type being inserted between the two brake block supports, and the fastening means of the wire as well as a portion of the bearing (8; 101; 231) bridging the brake disc (2; 103; 203) outside of its periphery.

7. Disc brake according to anyone of the preced ing claims, c h a r a c t e r i z e d b y the bearing com rising a bell-shaped housing (101) , which is open towards the centre of the brake disc and straddling the same, in the interior of which housing the brake block supports (106) with their brake blocks in oscillating arrangement are dis- placeably mounted in the depth direction of the housing, i. the radial direction of the brake disc (103) , as well as in the transversal direction of the housing, i.e. in or contra

OMPI to the direction of rotation of the brake disc, the guid¬ ing surfaces (lOld) cooperating with the brake block sup¬ ports converging towards the friction surface as counted in the depth direction of the housing as'well as in the direction of rotation of the brake disc.

8. Disc brake according to claim 7, c h a r a t e r i z e d b y the arms (108) of the brake block supp (106) extending outside of the periphery of the brake disc (103) being in between them connected by means of a toggle 0 joint link (109) , to the knee (111) of which a wire-like operating pulling means (115, 116) is coupled.

9. Disc brake according to claim 3, c h a r a t e r i z e d b the brake block support (6) being desi as a double-armed lever extending along the periphery of t ^ brake surface, the second arm (6a) being supported by said bearing against a sliding surface (9) converging towards the braking surface as counted in the direction of rotatio of said braking surface, the bearing (8) and the brake bloc support exhibiting in between them cooperating stops (6c, 1 in order to limit the return movement of the brake block support, i.e. its movement against the opposite direction to the direction of rotation of the brake disc.

10. Disc brake according to claim 9, c h a r a c t e r i z e d b y the brake block supports (6) projecting free from contact with the bearing (8) each one on its side of the brake disc (2) , the brake block supports being suppo ed by the bearing in a non-pivotable mounting as counted al the plane of the ^"brake disc, and the bearing, which by way example is supported by the wheel supporting fork (4) of a bicycle or similar, being supported in a non-pivotable moun ing and/or adjustable mounting relative to said fork as cou ed along said plane.