Abstract:
A caliper disk brake, particularly for commercial vehicles, comprising a carrier, a caliper, at least one brake pad, and an indicating device capable of indicating wear of said brake pad. Said indicating device comprises a screw drive converting a linear movement of said pad with respect to said carrier into a rotational move-ment. Moreover, the invention may include a wear indicating device of such a disk brake.

Description:
FIELD OF THE INVENTION 
     The invention relates to a caliper disk brake, particularly for commercial vehicles, comprising a caliper, a carrier, at least one brake pad and an indicating device capable of indicating wear of said brake pad. 
     BACKGROUND 
     Disk brakes as mentioned above are known. The known brakes include electronic indicating devices to indicate the wear of the brake pad. In other disk brakes, the pad wear is measured using a tape measure or a ruler. Such a measurement is not sufficiently precise. What is also known is to measure the pad wear via a pin extending more or less from the caliper or the carrier of the brake, depending on the wear of the brake pad. Like the electronic indicating devices, these known solutions are laborious and complicated. Moreover, said pin can get jammed due to dirt making the measurement incorrect. 
     One embodiment of the present invention is directed to a caliper disk brake as mentioned above which is simpler, particularly with view to the indicating device, while providing a correct and precise wear indication. 
     According to one embodiment of the invention, the indicating device comprises a screw drive converting a linear movement of said pad with respect to said carrier into a rotational movement. 
     Advantageously, such a converting gear is a very simple part and easy to manufacture. The angle of the rotational movement gives sufficient information about the wear of the pad because said wear corresponds to a respective linear movement of (a back plate of) the pad with respect to the carrier. This is particularly true for the part of the linear movement resulting from wear compensation performed by a respective adjusting device integrated into the brake. 
     In one embodiment, said screw drive comprises a screw and a nut, said nut cooperating with said screw to rotate if linearly moved relative to said screw. 
     Said nut can be provided in various forms, particularly in the form of a sleeve. 
     According to one embodiment of the invention, the screw is held non-rotatable. Thereby, it is guaranteed that any rotation of the nut merely results from a linear movement of the pad and thereby of the screw relative to the carrier. 
     To enhance accuracy of the wear indication, to the invention may include a spring urging said nut to move away from said screw in response to wear of said brake pad. In other words, said spring is used to reliably hold said nut axially so that all the movement of the screw results from respective movement of the pad. 
     Said indicating device, in one embodiment, comprises a display means. 
     Said display means can be provided in various forms. In one embodiment, said display means comprises at least a first field related to a still tolerable wear and a second field related to a no more tolerable wear. With this embodiment of the invention, a user can take from the indicating device whether or not the wear of the pad is still tolerable or whether the pad must be replaced because the wear is no longer tolerable, based on which one of the first and second fields is displayed. 
     According to a further embodiment of the invention, what is provided is a protecting means protecting said display means from the environment, particularly from dirt, stones and the like. 
     Said protecting means may, in one embodiment, comprise a window through which a wear indicating information can be seen. Such a wear indicating information can, for example, be said first or said second field. If the first field can be seen through the window, a user knows that the pad is still ok. If, however, the second field can be seen through the window, the user knows that the pad is to be replaced. Instead of a window, what can be provided is a marker, said marker marking either the first or the second field, depending on the wear of the pad. 
     To simplify the overall construction, said protection means is, in one embodiment, held non-rotatable. 
     In addition to the above disk brake, the invention may also provide a wear indicating device for such a disk brake. 
     SUMMARY OF THE DISCLOSURE 
     In one implementation, the present disclosure is directed to a caliper disk brake. The caliper includes a carrier, a caliper, a least one brake pad, and an indicating device capable of indicating a wear of said brake pad, wherein said indicating device comprises a screw drive converting a linear movement of said at least one brake pad with respect to said carrier into a rotational movement. 
     In another implementation, the present disclosure is directed to a wear indicating device for use in a caliber disk brake including a carrier, a caliber, and at least one brake pad, the indicating device including a screw drive for converting a linear movement of the at least one brake pad with respect to the carrier into a rotational movement; and display means associated with said screw drive for displaying the extent of wear of said at least one brake pad. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For the purpose of illustrating the invention, the drawings show aspects of one or more embodiments of the invention. However, it should be understood that the present invention is not limited to the precise arrangements and instrumentalities shown in the drawings, wherein: 
         FIG. 1  is a schematic partly cutaway top view of a brake disk according to one embodiment of the invention; 
         FIG. 2  is a schematic partly cutaway side view of the brake of  FIG. 1 ; and 
         FIG. 3  is a three exploded assembly drawings of an indicating device of the brake of  FIGS. 1 and 2 . 
     
    
    
     DETAILED DESCRIPTION 
     The disk brake shown in the accompanied drawings comprises a carrier  10  and a caliper  12 . Caliper  12  is held slidably with respect to carrier  10  by sleeves  14 ,  16 , which are fixed to carrier  10  by bolts  18 ,  20  and on which caliper  12  can slide. 
     Said brake furthermore includes brake pads  22 ,  24  which are urged against a brake disk (not shown) when the brake is activated. 
     Corresponding to the wear of brake pads  22 ,  24 , caliper  12  is shifted relative to carrier  10  to the right-hand side in  FIG. 2  or upwards in  FIG. 1 , respectively. To this end, what is provided in the brake shown in the drawings is an automatic adjustment device which is perfectly known in the art and, therefore, not further explained. 
     To indicate the (total) wear of brake pads  22  and  24 , what is provided is a wear indicating device  26 , detailedly shown in  FIG. 3 . Said wear indicating device comprises a cap  28 , a sleeve  30 , a spring  32 , and a screw  34 . Screw  34  comprises a thread  36  and sleeve  30  comprises protrusions on its inner wall, one of these protrusions being numbered  38  in the enclosed drawings. Protrusions  38  cooperate with thread  36  so that screw  34  and sleeve  30  combine to a screw drive, with sleeve  30  being the nut. 
     Although not shown in the drawings, when mounted, screw  34  is provided with a rubber ring held in groove  40 . Said rubber ring serves for fixing screw  34  rotationally to bolt  20 , when said rubber ring in groove  40  is inserted into the hexagon socket of bolt  20 . 
     While screw  34  is held rotationally fixed, sleeve  30  can rotate about its longitudinal axis. To this end, cap  28  is provided with a dome-shaped support  42  and sleeve  30  comprises a mating recess  44 . 
     In the direction of the longitudinal axes of screw  34  and sleeve  30 , screw  34  is coupled to bolt  20  and thereby to carrier  10 , whereas sleeve  30  is coupled to caliper  12  to be reliably held axially so that it follows the axial movement of caliper  12  and is set into rotational movement due to the screw drive function. 
     By the way, spring  32  is not shown in  FIG. 1 , but in  FIGS. 2 and 3 . 
     Sleeve  30  comprises an alignment rib  46  to reliably cooperate with screw  34 . 
     Sleeve  30  comprises a display means in form of 3 fields  48 ,  50 ,  52 , which are colored. In the enclosed example, field  48  is green, field  50  is yellow, and field  52  is red. 
     Cap  28  may be transparent and held rotationally fixed by protrusion  54 . It is particularly meant for protecting sleeve  30  and screw  34  from dirt. 
     Cap  28  may further comprise a marker  56 . 
     If completely assembled and mounted to the disk brake, wear indicating device  26  is in such a status that marker  56  is positioned above green field  48  in case that pads  22 ,  24  are new and not yet worn. 
     If the brake is used, pads  22 ,  24  are worn, resulting in that caliper  12  is shifted in  FIG. 1  upwardly and in  FIG. 2  to the right-hand side with respect to carrier  10 . Since screw  34  is coupled to carrier  10 , whereas sleeve  30  is coupled to caliper  12 , said shifting of caliper  12  with respect to carrier  10  results in a respective rotational movement of sleeve  30 , so that yellow field  50  and red field  52  step by step approach marker  56 . Marker  56  above yellow field  50  means a warning to a user that pads  22 ,  24  are soon to be replaced. If marker  56  is above red field  52 , the user is informed that the wear of pads  22 ,  24  is no longer tolerable and they must be replaced. 
     In the above described embodiment, screw  34 , sleeve  30 , and cap  28  are made of plastic materials, with cap  28  being transparent. According to an alternative embodiment, however, cap  28  can be made of metal material with a window instead of marker  56  with fields  48 ,  50 ,  52  being visible through said window, dependent on the rotational position of sleeve  30 . Said window need not be a simple opening, but may be provided with a (plastic) window pane, considering the protecting function of cap  28 . Other designs for cap  28  are also encompassed by the present invention. 
     The features disclosed in the above specification, claims and the drawings may be essential also in various combinations for the implementation of the invention in its varied embodiment forms. 
     Exemplary embodiments have been disclosed above and illustrated in the accompanying drawings. It will be understood by those skilled in the art that various changes, omissions and additions may be made to that which is specifically disclosed herein without departing from the spirit and scope of the present invention.