Abstract:
The invention relates to a liquid controlled disk braking device having a brake disk, brake caliper, and a caliper carrier. The brake disk is postionable on the roller of a main hoist and forms a brake pair together with the brake calipers. A combination of service and emergency calipers, each caliper being responsive to fluid pressure, is used to effect operational and stationary braking. Service calipers are used to apply operational braking forces against the brake disk when the disk is rotating, applying braking forces when subjected to fluid pressure. Emergency calipers are used to apply braking forces when the brake disk is stationary or when liquid pressure to the caliper has been removed or lost.

Description:
FIELD OF INVENTION 
     The present invention relates to an improved configuration for liquid controlled disk braking devices and is applicable to winch brakes of petrol drills, well rigs and shaft hoists, and to brake and speed controls for hoists. 
     BACKGROUND OF THE INVENTION 
     Mechanical band brakes have traditionally been used in the prior art for various applications including winch braking devices of petrol drills, well rigs, and shaft hoists. However, due to inherent design characteristics, such devices are frequently unable to provide adequate braking torque and have been plagued with problems of unreliability, unstable braking effects, heat emissions, and difficulty in operation, adjustment, and maintenance. Such limitations tend to detrimentally affect equipment life, efficiency and required operational time. 
     The object of the present invention is to provide a liquid controlled disk brake having the advantages of increased braking torque, braking stability, sensitivity and precision in control, quick operation, easy installation and maintenance. Also desired is a design in which automatic apparatus control may be more easily incorporated into the overall system by allowing braking to be effected by either introducing or removing fluid pressure to particular components of the apparatus. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention, a liquid controlled disk braking device comprises a brake disk, brake calipers and a caliper carrier. The brake disk is fixed to the roller of a main hoist, which forms a brake pair together with the brake calipers. The caliper carrier is arranged on a winch base to position each of the brake calipers with respect to the brake disk. The brake calipers include both operational or service calipers and emergency calipers, which vary in relative number according to the braking needs of the particular machine or application. 
     The service calipers are used to provide braking force when the brake disk is rotating. Each service caliper includes two brake blocks positioned on either side of the brake disk with sufficient clearance to permit the disk to rotate. An oil cylinder connected to both brake blocks forces the blocks against the disk when the cylinder is pressurized and restores clearance when pressure is removed. 
     The emergency calipers are used to provide braking force when the disk is parked or in an otherwise stationary position. Like the service calipers, each emergency caliper includes two brake blocks positioned on either side oft he brake disk and connected to an oil cylinder. However, unlike the service calipers, each emergency caliper&#39;s oil cylinder is configured to force the blocks against the disk when the cylinder is non-pressurized and restores clearance only when pressure is restored to the cylinder, thereby providing additional safety braking in the event of a loss of oil pressure to the system. 
     Features of the current invention include the ability to easily vary the amount of available total braking force by merely adapting the total number of braking clamps according to the particular needs of an application. Also included is an ability to provide additional braking force in the event of lost pressure to the braking system. 
     While the preferred embodiment oft his invention utilizes oil as the pressurizing fluid for the cylinder of each operational and emergency caliper, it will be appreciated that the invention contemplates other pressurizing fluids as well. The invention also contemplates other number combinations of operational and emergency calipers according the need of each particular application. 
     Thus, the invention does not reside in any one of the features of the liquid controlled disk braking device which is disclosed above and in the Description of the Preferred Embodiments and claimed below. Rather, this invention is distinguished from the prior art by its particular combination of features of the liquid controlled disk braking device disclosed. Important features of this invention have been disclosed in the Detailed Description of the Preferred Embodiments of this invention which are shown and described below to illustrate the best mode contemplated to date of carrying out the invention. 
     Those skilled in the art will realize that this invention is capable of embodiments which are different from those shown, and the details of the structure of the braking device can be changed in various manners without departing from the scope of this invention. Accordingly, the drawings and description are to be regarded as illustrative in nature and are not to restrict the scope of this invention. Thus, the claims are to be regarded as including such equivalent liquid controlled braking devices as do not depart from the spirit and scope of this invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of the present invention and the main roller. 
     FIG. 2 is a perspective view showing the service caliper, emergency caliper, brake disk and caliper carrier that are the subject of the invention. 
     FIG. 3 is a front sectional view of the service caliper. 
     FIG. 4 is a side view of the service caliper depicted in FIG.  3 . 
     FIG. 5 is a front sectional view of the emergency caliper. 
     FIG. 6 is a side view of the emergency caliper depicted in FIG.  5 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIGS. 1-6 generally illustrate that the liquid controlled disk braking device mainly comprises a brake disk  1 , brake calipers  30  and caliper carrier  4 . FIGS. 1 and 2 illustrate the substantially circular brake disk  1  fixed tightly to a main winch roller  31  which is combined with the brake calipers  30  as a brake pair  32 . The caliper carrier  4  is arranged on a winch base. The brake calipers  30  are each connected to the caliper carrier  4 . The brake calipers  30  include a service caliper  2  and an emergency caliper  3 . 
     Referring now to FIGS. 3 and 4, the service caliper  3  includes brake blocks  5  positioned proximate to the two major surfaces of the brake disk  1  which is not shown in FIGS. 3 and 4. The brake blocks  5  are each fixed to caliper body  6  at one end of a lever  7 . A supporting rod  8  is fixed tightly to caliper carrier  4 . The two ends of supporting rod  8  cooperate smoothly with a lever notch  33  in a radial direction through shaft pin  9 . The levers  7  rotate on shaft pins  9 . The other ends of the two levers  7  are connected separately to a piston rod  10  through shaft pin  12   a  and to oil cylinder  14  through shaft pin  12   b . An oil cylinder cap  13  is fixed to the oil cylinder  14 . The piston rod  10  cooperates smoothly with the oil cylinder  14 . Two tension springs  15  are placed parallel on the two ends of the two shaft pins  12   a  and  12   b . One end of each tension spring  15  is joined up with spring screw  11   a  of shaft pin  12   a  connected to the piston rod  10 . The other end of each tension spring  15  is connected with spring screw  11   b  of shaft pin  12   b  connected to the oil cylinder  14 . 
     In operation, the piston rod  10  moves relative to the oil cylinder  14  to cause the brake blocks  5  to apply braking forces against the brake disk  1  under the force of the levers  7 . Before the addition of pressurized oil to the oil cylinder  14 , the service caliper  2  is relaxed. At this time, the brake blocks  5  are held away from the major surfaces of the brake disk  1  by tension spring  15  so that there is clearance between the blocks  5  and disk  1 . Pressurized oil is then filled into the cavity of the oil cylinder  14  of the service caliper  2  via an oil inlet. A piston within the oil cylinder  14  pushes the piston rod  10  out from the oil cylinder  14  so that the piston rod  10  and cylinder  14  move relative to each other, pushing the levers  7  outward on both ends. This relative movement of the levers  7  works against the tension forces of the tension springs  15  so that the brake blocks  5  move inward and in opposite directions to clamp the brake disk  1  and to carry out operational braking. When the brake blocks  5  are forced against the brake disk  1  due to the added oil pressure, a positive pressure force is produced between the brake blocks  5  and disk  1 , such positive pressure being in proportion to the oil pressure in the oil cylinder  14 . The higher the oil pressure, the greater the braking torque. When the oil pressure is unloaded, the brake blocks  5  are separated from the brake disk  1  under the tension force of the tension springs  15  and the piston returns to its original relaxed position under the spiral spring force. 
     Now referring to FIGS. 5 and 6, the emergency caliper  3 , like the service caliper  2 , includes brake blocks  5  that are positioned proximate to the sides of the outside edges of the brake disk  1 , the brake blocks  5  being fixed to the caliper body  6  and connected to one end of the lever  7 . Supporting rod  8  is fixed to the caliper carrier  4 . The two ends of the supporting rod  8  cooperate smoothly with the lever notch  33  in a radial direction through shaft pin  9 . The lever  7  rotates on the shaft pin  9 . The other ends of the two levers  7  are connected with piston rod  16  through shaft pin  17   a  and with top rod  24  through shaft pin  17   b  separately. The piston rod  16  is connected to a piston rod step  34  which is in turn connected to one end of disk spring group  19 . The other end of the disk spring group  19  is connected with the bottom  35  of oil cylinder  20 . An oil cylinder cap  18  is fixed to oil cylinder  20 . The piston rod  16  cooperates smoothly with the oil cylinder  20 . The step  36  of top rod  24  is inserted into the step  37  of adjustable nut  22  and fixed with spacer  23  on the bottom of the adjustable screw  38  tightly through the bolt. Blocking nut  21  and adjustable nut  22  are fixed through threaded connection to the outside edge  39  of oil cylinder  20 . The adjustable nut  22  permits adjustment of the axis clearance between the top rod  24  and the oil cylinder  20 , thereby permitting adjustment of the brake clearance of the emergency caliper. A blocking nut  21  then locks the adjustable nut  22  in position. 
     Unlike the service caliper  2 , which is an oil feeding brake for operational braking, the emergency caliper  3  is an oil return brake. As with the service caliper  2 , the piston rod  16  of the emergency caliper  3  moves relative to the oil cylinder  20  to cause the brake blocks  5  to apply braking forces against the brake disk  1  under the force of the levers  7 . Before the addition of pressurized oil to the oil cylinder  20 , the emergency caliper  3  is also relaxed. However, unlike the service caliper  2 , the relaxed emergency caliper  3  pushes the brake blocks  5  against the brake disk  1  so that there is no clearance between the blocks  5  and disk  1 . 
     In operation, pressurized oil is filled into the cavity of the oil cylinder  20  of the service caliper  3  via an oil inlet. The piston rod  16  moves with respect to the oil cylinder  20 , using the piston rod step  34  to press against the tension forces of the disk spring  19  so that the levers  7  on both ends are pulled and the brake blocks  5  are pulled away from the brake disk  1 , allowing the brake disk  1  to rotate freely. Brake clearance can be adjusted through the adjustable nut  22  to compensate the brake&#39;s wearing capacity. When the oil pressure is removed from the oil cylinder  20 , the restoring tension force of the disk spring  19  pushes the brake blocks  5  through the levers  7  to clamp the brake disk  1 , restoring the emergency caliper  3  to its relaxed state. Thus, unlike the service caliper  2 , the emergency caliper  3  uses the force of the disk spring  19  to carry out its braking action. 
     The fact that the emergency caliper  3  provides braking action only in the absence of oil pressure and that this operational state is opposite to the operational state of the service caliper  2  makes the emergency caliper  3  appropriately used for emergency and parking braking. The contrary operating states of the operational and emergency calipers  2  and  3  also permits for the construction of a compound braking system using an interactive dual braking structure. The actual relative number of service or emergency calipers used is determined by the specific braking needs of a particular application. 
     The combined levers  7  have a “cross-type” structure. The two ends of the supporting rod  8  are put into the notch in the middle of the lever  7  so that the rod  8  can move flexibly and be easily installed or dismantled. Such a configuration allows the apparatus to incorporate fewer components and less structural material without unduly sacrificing overall strength. The configuration also helps to protect contacting surfaces of the supporting rod  8 , lever  7  and the shaft pin  9  and to reduce corrosion. It has a clean appearance and is relatively simple to use. 
     The invention is also inherently well-suited for meeting the needs of normal operational braking and emergency braking. The design has great capacity of braking torque and stable braking effect with low braking inertia due to the inclusion of multiple braking calipers. Further, the design permits braking effort to be easily adjusted with easy operation and maintenance.