CA1227144A - Braking force feedback for caliper type brakes - Google Patents

Abstract

BRAKING FORCE FEEDBACK DEVICE FOR CALIPER TYPE BRAKES

Abstract of the Disclosure A caliper disc braking force feedback device is disclosed which utilizes a unique pivotal mounting for the disc brake in combination with a force sensing unit which creates a hydraulic pressure signal in proportion to the braking force. The hydraulic pressure signal is applied to a conventional brake cylinder which, in turn, is operatively connected to the control handle for applying the brake. This, in combination with a unique proportional mounting for a control valve, re-sults in improved operator feedback resulting from pro-portional control in the operating lever and a "solid bottom" feel when the brake fully stops the device.

Description

1227~44 --1-- .....

BR~KIldC~ FORCE FEEDFsACK DEVICE FOR CALIPER TAIPEI BRAKES

Background of the Invention Disc caliper brakes are known in the art and have been used for such applications as braking propeller shafts, and drill strings on well servicing and drilling equipment. The applications, particularly in well servicing and drilling equipment, have not been completely successful due to the nature ox caliper disc brakes.
A caliper disc brake is applied by squeezing a brake pad to a disc which is rotating with the shaft or equipment, the rotation of which is desired to be con trolled or stopped. The method of application is to-tally independent of how the machine or shaft responds to the brake application. Therefore, the operator has no "feel" of how the brakes are performing. In other words, application of the caliper disc brake does not result in any perceptual feedback to the operator and thus the operator is unaware of the degree of braking taking place. This is particularly complicated when the brake malfunctions, hangs up due to friction, dirt or the like, or the surface of the brake becomes a-footed by water, oil, or other surface contaminants.
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Object of the Invention The present invention provides the operator ox, for example, a work over or drilling unit, an actual - "feel" of the performance of the caliper disc brake.
An object of the present invention therefore is to provide a braking force feedback signal which is recog-sizable by the operator and which is directly proper-tonal to the actual braking force that is occurring.
- An object of the present invention is to mount the lX27~44 I

1 caliper disc brake so that a portion of the reactive force created by the brake action is transmitted to a --pressure sensing means, and the pressure sensing means -in turn imparts a reactive force to the operating lever for the actuation of the disc brake, which the operator ---may sense or feel. -- A further object of the invention is to provide a ---safe, simple and economic means of accomplishing open-atop feedback which is essentially failsafe in --- 10 operation.
These and other objects are obtained in a braking -force feedback system for caliper disc brakes -- comprising a means for applying a braking force, a --control means for controlling the applied braking force operatively coupled to the means for applying a braking -force, the control means being operable in response to -a manual movement, a sensing means for sensing at least ---a portion of the braking force, and feedback means no- -sponsive to the sensing means for creating a proper- :
- 20 tonal force to resist the manual movement whereby an --I
operator can sense the amount of braking force. :-- luff Description of the Drawings FIG. 1 is an isometric overall assembly view of a --braking force feedback system according to the present --invention. --FIG. 2 is a partial cross section in elevation ox the force sensing cylinder of the preferred embodiment - of the present invention. -FIG. 3 is an elevation view of an operating lever and lever force cylinder utilized in the present - invention.
FIG. 4 is a partial cutaway plan view of FIG. 3.
FIG. 5 is a side elevation view of the mounting or ,, . . .

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1 the brake operating valve according to the present invention.
FIG. 6 is a front elevation of the brake operating valve according to the present invention.
Description of the Preferred embodiment The following described embodiment is offered by way of further describing the invention in terms ox a presently preferred embodiment.
Referring to FIG. 1, a braking force feedback soys-them according to the present invention is shown in a schematic isometric assembly view. A conventional eel-wiper type disc brake, designated by reference numeral 1, is shown engaging a brake disc 2 which may be also-elated with any rotating member whose rotation is desired to be controlled or stopped. In particular, such rotating member may be, typically, a drill string or similar rotating shaft wherein the degree ox braking force developed is of concern to the operation of the equipment.
The caliper mechanism 3 comprises an opposed pin lever mechanism which accomplishes equal and opposite force application on the brake pads 4 in response to wedging action produced by an operating wedge 5. The operating wedge 5 is introduced to the caliper mocha-noisome 3 by means of a pneumatic piston/spring brake act tutor 6 through the piston rod 7 driven by the Noah-matte actuator. For purposes of the preferred embodiment, the pneumatic piston/spring brake actuator - 30 may be similar to the Commutate spring brake actuator manufactured by Aero-Quip Corporation ox Jackson, : Michigan USA. The Commutate actuator provides two-part braking the first, a service brake which is applied on positive application of pneumatic pressure, and a sea-AYE --I
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pond emergency brake which is spring applied on loss of system pressure, as later described. The wedging act lion transmitted through the caliper mechanism creates a clamping force on the brake pads 4 which, in turn, clamp in equal and opposite manner against brake disc

2, thereby producing the desired braking action.
The caliper 1 is shown mounted to a pivoting base 10. Pivoting base 10, in turn, is mounted by means of pivoting shaft 11 to a fixed base 12. It may be appreciated by one skilled in the art that, assuming counterclockwise rotation of the brake disc, braking force created by the clamping of the brake pads 4 will result in a braking force directed vertically downward as shown in FIG. 1. The resulting reaction force on Thea brake pad would, of course, be vertically upward and resist the counterclockwise rotation of the brake disc and hence, through its connection to a rotary member, the force would resist rotation of that member.
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The vertically upward braking force on the brake --pods would tend to rotate the caliper 1 in a clockwise --direction about pivot shaft 11. In the preferred embodiment, a force cylinder 15 is provided to resist Jo the clockwise rotation of the caliper as transmitted -through pivoting base 10. It may be appreciated by one squealed in the art that the force applied to the force --cylinder 15 is therefore directly proportional to the -braking force generated by the brake pads, and is index pendant of any forces required to operate the caliper brake.
Thea construction of the force cylinder 15 is best seen in FIG. 2. The force cylinder, in general, is a large diameter, short stroke hydraulic piston which -converts the mechanical force into a hydraulic pressure ---sufficient to resist the force. In FIG. 2, the `
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pivoting base 10 is shown connected to an annular pus ton 20 by means of stud bolts 21. The annular piston 20 bears upon disc plunger 22 which, in turn, bears and distributes the force load on diaphragm 23.
A hydraulic chamber 25 is formed between the die-from 23 and a shallow cup shaped cylinder base 26.
The piston 20 is axially guided and retained by a z-cross section retainer ring 27. The retainer ring 27 also clamps the diaphragm 23 to the cylinder base.
- 10 A convenient number of multiple clamping bolts 29 are provided about the periphery of the cylinder base to clamp the retainer ring 27 and diaphragm 23 to the cylinder base. Clamping bolt 29, shown in phantom, clamps the diaphragm 23 between the retainer ring 27 and the cylinder base. A convenient number of multiple mounting bolts 30 and nuts 31 are provided about the periphery of the force cylinder to mount it to the - fixed base.
It should be understood that the force proportion-at to the braking force, which is applied to the pivoting base and thereby to the force cylinder, is converted into hydraulic pressure sufficient to resist - the force in hydraulic chamber 25. The hydraulic champ - bier is filled with hydraulic fluid which is transmitted through a hydraulic line 35, which is connected to the f once cylinder 15 by a convenient connection (not shown) which communicates with the hydraulic chamber.
In the preferred embodiment, the pneumatic piston actuator 6 forces the wedge 5 to activate the caliper mechanism 3 when air is supplied through operating air - line 40. Operating air is received from a convenient - air supply source, such as an air reservoir 41.
- In the preferred embodiment, air from air riser-- void 41 is supplied to the pneumatic piston actuator 6 .. ..

:1227144 -I
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1 through a series of operating valves and air supply ---lines. The service brake receives air from reservoir --41 through line 44 to brake operating valve 45, and -I
when the brake operating valve 45 is opened, air is --supplied through line 40 to the pneumatic actuator 6. -The brake operating valve 45 is preferably an on/off -venting valve, for direct operation by means ox a lever -actuator 46, such as provided in the preferred --embodiment. --The valve actuating lever 46 is shown rotating a- --bout a pivot 47. The lever 46 is applied by means of -brake cable 50 in a conventional manner. It should be understood that air from air reservoir 41 is be sup- ---- plied to activate the pneumatic piston actuator through --air supply line 44, brake operating valve 45, and open- -cling air line 40. Air will be supplied when the valve -actuating lever 46 is depressed against valve plunger :
48. It should also be understood, at this point, that ---- valve actuating lever 46 is actuated by brake cable 50. --In addition to the service brake, a spring opera- -ted pneumatic released emergency brake is incorporated I-in the pneumatic piston/spring actuator 6. To accom- ---polish release of the emergency brake system, air from reservoir 41 is supplied to a palm operated normally on delivery vented valve 43 through line 42. Air supplied ---through palm valve 43 is applied through line 51 to a normally closed delivery vented pilot operated valve 53. The air supplied through line 51 serves as the pilot signal to maintain valve 53 in an open position, -I
- 30 whereby air from reservoir 41 is supplied through line --52 to the spring brake retractor. Emergency release -=
- and activation of the spring brake may be accomplished - by depressing palm valve 43 which vents the air pros-sure supplied to pilot valve 53, thereby closing valve --...

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AYE - -53 and allowing it to vent the spring brake retractor through line 52, thereby allowing the spring brake to I---be applied. :
It should also be understood that Should the soys- --them lose all pressure, the spring brake would also be --automatically applied as a safety device.
Another feature of the system resides in the --I
mounting of the brake operating valve 45, the valve actuating lever 46, and the brake cable 50. FIG. 5 -shows a side elevation of the mounting for the brake --operating valve. Bracket 60 is secured to the piston ---rod 7 by means of a slide collar and double nut en- -:-rangement as shown. Any convenient attachment however --I
- would be adequate as long as the bracket 60 is secured ---so as to move with the wedge 5. -Referring to FIG. 6, valve actuating lever 46 is --shown mounted to the bracket 60 by means of a pivot 47 -in such a manner as to allow depression of valve plunge -or 48 by the valve actuating lever 46. Cable 50 is ---mounted by its outer sheath to a bracket on caliper --frame 3. The purpose of this mounting system is that when the brake lever 55 is applied to a position and ---held there, the push-pull cable 50 pulls on the lever --46. This results in the depression of valve plunger 48 -Iand the brake operating valve 45 is opened allowing air --flow to the actuator 6. This increases pressure in the -actuator service chamber which results in the downward deployment of the piston rod 7 r the wedge 5, and break- -et 60. Since the cable is mounted to the caliper frame, the downward movement of the wedge 5 and the --valve 45 releases the force of lever 46 on the valve. -This action then tends to close the valve 45, and tray-of of wedge 5 stops and is maintained in this position. ---- In this situation, the valve 45 is held in its neutral -1227~44 1 position.
If the brake handle 55 is further depressed, a --further increment of application is achieved. If the -brake handle 55 is released, the lever 46 releases the --I
- 5 plunger of valve 45 and the air in the actuator 6 servo --ice chamber is again in proportion to the amount of --release. -Another important feature of the system is its a-ability to achieve a "solid bottom" feel on handle 55. :--This is achieved by the geometry of the load sensing --feedback system. Under normal braking conditions with --I
the disc rotating, the friction vector between the pads `
- -and the disc is essentially vertical as shown in FIG. --I
1. This creates a moment about pivoting shaft 11. The --moment is counteracted by the force applied by the `
- sensing cell or force cylinder 15. The piston area ray two between the brake cylinder 65 and the force Cal-inter 15 is such that the operator can overcome the maximum moment the system can apply. When the disc no- --station stops however, it should be appreciated that the friction vector loses its vertical direction and as- --sums a direction at approximately right angles to Yen- -tidal to resist the moment now applied by the force -:::::
cylinder 15 about pivoting shaft 11. Since the moment --arm between the vertical friction force and the Herr zontal friction force about the pivoting shaft 11 is --`
different, a different feel in the handle 55 results ---when disc rotation stops. In the preferred embodiment, --the moment arm for the horizontal friction force is substantially larger (approximately four times), there -fore stopped disc rotation will result in a substantial solid bottom feel exhibited in the handle 55.
- The combination of the braking force feedback de- :-. . .
vice and position responsive operation of brake opera-:- , I I
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1 tying valve 45 results in an operator controlled feed- -back system never before possible with caliper type ---disc brakes. -Referring now to FIGS. 3 and 4, a brake handle 55 is shown mounted on a bell crank 56 for rotation -therewith about an axis perpendicular to the longitude- ----net axis of the handle. The bell crank 56 is pivotal -mounted on a mounting plate 57 which is in turn mounted --to the brake handle case 58. There are two projecting levers in addition to the brake handle 55 forming bell -crank Thea first, a brake actuating lever 59, and ---the second, a reaction lever 60. Brake actuating lever 59 retracts brake cable 50 through adjustable rod 61. -In the preferred embodiment, the brake cable is a conventional sliding armored cable, sometimes referred ---to as a choke cable, and operates in a conventional manner in that when cable rod 61 is displaced towards ---the right, as shown in FIG. 3, the flexible center cay -bye will transmit the movement to valve actuation lever `
46, shown in FIG. 1. This motion displaces the valve --actuation lever 46 and thereby the valve plunger 48 to operate the brake operating valve. It may thus be seen that pushing brake handle 55 down results in applique-lion of the disc brake.
The outside cable of the brake cable 50 is attach- --Ed to a mounting bracket 62 in a conventional manner -:
for such cables. The second lever on the bell crank is --reaction lever 60, which is connected to an adjustable --reaction rod 63. The reaction rod in turn displaces a -small bore hydraulic piston which reacts to the hydra-fig pressure and hydraulic fluid flow produced in the --force cylinder 15 in response to the braking reaction:-:
force. `-For purposes of the preferred embodiment, it has ~Zz7~D~4 ---1 o-- - -1 been found extremely convenient to utilize a convent tonal automotive or truck type master cylinder for this purpose. Therefore, shown mounted on mounting plate 57 is a typical heavy duty brake master cylinder 65. The use of a conventional brake master cylinder has been found convenient because of its reservoir cay paucity and suitable construction, although its prince-pal function is reversed in the present application, as will now be explained.
In a normal master cylinder function, displacement of the adjustable reaction rod 63 to the left would no-suit in hydraulic pressure and fluid flow exiting ho-draulic line connection 66. This hydraulic fluid would activate the brakes of a vehicle to cause the Ye-hide to stop. In the present application, however, the function is reversed in that hydraulic fluid is pressurized in the force cylinder 15 and allowed to flow through hydraulic line 35 into the hydraulic line connection 66 which, in turn, forces the small diameter piston to be displaced to the right. Adjustable react lion rod 63 is also thereby displaced to the right.
The movement of the reaction rod transmitted through bell crank 56, results in an upward movement of the brake handle 55.
In summary, as the operator depresses the brake handle 55, the control valve 48 will supply air to the pneumatic piston actuator 6 and the brake will be applied. In response to the application of the brake, a resulting force will be applied in proportion to the amount of braking reaction force applied to force Cal-inter 15. Force cylinder 15, in turn, will produce ho-draulic fluid pressure and flow which will be applied to the brake master cylinder 65. Movement of the small bore piston in the brake master cylinder results in a ~;~2~44 ::

., . _ _ . .
1 force resisting the downward movement of the brake ken- --die in proportion to the amount of braking. A Unsolid ---bottom feel is achieved when the rotation is stopped -completely.
The proportional resistance or feedback produced --by this system assists the operator in determining pro- --wisely the amount of braking force occurring and, in ......
fact, the amount of braking is proportional to the ---force applied to the handle. The amount of reaction, and therefore the amount of braking for a given force ---in the brake handle, may be controlled by relocation ox the pivot shaft 11 relative to the effective lever arm --between the brake pad and the pivot point, and the peeve ox point and the point of application ox the force on the force cylinder. In addition, it may also be en footed by choice of appropriate relative cylinder sizes -between the force cylinder and the brake master Solon- --don and/or, alternatively, the length of the reaction -lever 60 relative to the length of the brake handle 55.
waving described my invention in terms of a pro- ---furred embodiment, numerous modifications or substitu-lions of equipment may be made by one skilled in the --art. Therefore, I do not wish to be limited in the scope of my invention except as claimed.
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Claims (23)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY OR
PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A braking force feedback system comprising:
a means for applying a braking force;
a control means for controlling the applied braking force, operatively coupled to said means for applying a braking force;
said control means being operable in response to a manual movement;
a sensing means for sensing at least a portion of said braking force; and feedback means responsive to said sensing means for creating a proportional force to resist said manual movement whereby an operator can sense the amount of braking force.

2. A braking force feedback system according to claim 1 wherein said means for applying a braking force further comprises a disc brake.

3. A braking force feedback system according to claim 2 wherein said control means comprises, in part, a control valve for pressure fluid.

4. A braking force feedback system according to claim 3 wherein said control means further comprises a pressure fluid force producing device which applies said disc brake.

5. A braking force feedback system according to claim 4 wherein said pressure fluid is air.

6. A braking force feedback system according to claim 4 wherein said control means further comprises a lever means operatively coupled to said control means for actuation of said control means.

7. A braking force feedback system according to claim 6 wherein said lever means is cable operated.

8. A braking force feedback system according to claim 1 wherein said sensing means comprises, in part, a pivotal mounting means for said means for applying a braking force.

9. A braking force feedback system according to claim 8 wherein said pivotal mounting means comprises a mechanical advantage lever mounting means for producing a resultant force proportional to said braking force.

10. A braking force feedback system according to claim 9 wherein said lever mounting means produces a resultant force of a magnitude proportional to the braking force applied to a rotating disc and a higher resistive force on a stalled disc.

11. A braking force feedback system according to claim 8 wherein said sensing means further comprises a resultant force sensing means.

12. A braking force feedback system according to claim 11 wherein said resultant force sensing means comprises a hydraulic piston means.

13. A braking force feedback system according to claim 12 wherein said hydraulic piston means supplies hydraulic pressure fluid to a means for resisting said manual movement,

14. A braking force feedback system according to claim 12 wherein said means for resisting said manual movement comprises an automotive type hydraulic cylin-der with its output connected to said hydraulic piston means.

15. A braking force feedback system according to claim 14 wherein the mechanical input of said hydraulic cylinder is operatively connected to said control means to proportionally resist said manual movement.

16. A braking force feedback system according to claim 15 wherein said means for applying manual movement is a hand lever.

17. A braking force feedback system according to claim 16 wherein said hand lever operates a bell crank to which both of said means for controlling the applied braking force and said feedback means are operatively connected.

18. A braking force feedback system according to claim 1 wherein said control means further comprises a control valve for fluid pressure to be applied to said means for applying a braking force mounted for movement with said means for applying a braking force so that movement applying a braking force proportionally closes said control valve and movement reducing a braking force proportionally opens said control valve.

19. A braking force feedback system according to claim 18 wherein said control valve is mounted for movement with the operator for a caliper type disc brake.

20. A braking force feedback system according to claim 19 wherein said control valve is further operated by a sheathed cable controlled lever means, and said cable sheath is affixed to a non-moving support.

21. A braking force feedback system comprising:
a pivotally mounted pressure fluid operated cali-per disc brake which allows pivotal movement of said caliper brake in proportional response to the braking force applied;
a pressure fluid supply to said disc brake;
a mechanically operated control valve for interrupting said pressure fluid supply operable in re-sponse to a manual movement of a control lever;
a hydraulic pressure signal device for resisting said pivotal movement and producing a hydraulicc pres-sure in proportion to said braking force;
a hydraulic piston device for providing a force and movement proportional to said hydraulic pressure;
said hydraulic piston device producing a force proportional to said braking force which resists said manual movement of said control lever through me-chanical linkage.

22. A braking force feedback system according to claim 21 wherein said pressure fluid is air.

23. A braking force feedback system according to claim 21 wherein said hydraulic piston device further comprises an automotive type hydraulic master cylinder.