MXPA99008788A - Hydraulic brake controller - Google Patents

Abstract

The invention includes a brake system for a hydraulic ram (3) or another cylinder, that can be employed as an emergency brake for a lifting elevator. When actuated, the brake arms (27) contact the ram circumferentially to slow and stop the falling ram. The brake arms are preferably lined with an able material that frictionally engauges the ram to stop the downward motion of the ram. The brake system may be actuated by the loss of hydraulic pressure, by an electronic signal from a hydraulic pressure detector, by down overspeed sensor (40) or by an uncontrolled down motion detector. According to another aspect of the present invention, a controller, which is preferably a programmed control system, compares the actual motion of the elevator as sensed by a detector to a desired motion. Under certain conditions, if the actual motion differs from the desired motion, the controller actuates the brake.

Description

HYDRAULIC BRAKE CONTROLLER FIELD OF THE INVENTION The present invention relates generally to safety brakes which stop the movement of a hydraulic jack, a plunger or a ram without permanently damaging or destroying it, and with a controller for such a safety brake.

BACKGROUND OF THE INVENTION There are many brake systems developed to stop hydraulic ram lifters during emergency situations. All the prior art patents found are directed towards metal rings that during a failure of hydraulic pressure will fall down and wedge between a fixed housing and the ram of an elevator. The friction generated by the downward movement of the ram in contact with the metal ring or the brake shoe causes the metal ring or the tapered brake shoe to be pushed downwards, so that the ram is wedged in by braking it. Empirical evidence indicates that the force required to stop an elevator using such a brake exceeds the elastic limit of the material used to build commercial battering rams. As a result, the ram can be deformed into an hourglass shape at the point where the brake holds the ram. Since this type of damage to the ram can not be repaired, the ram and in some cases its associated components must be replaced in order to restore the elevator to its working condition. Substituting the ram is time consuming and expensive. Because the elevator brakes described in the prior art patents have a relatively large number of moving parts, they are relatively complex. Additionally, the devices of the prior art are relatively large and bulky. When designing a braking system, size is an important consideration because there is often limited space within which to place a braking device. Therefore, in order to facilitate the installation of new brake systems within hydraulic elevators, it is desirable that they have a low profile. A specific example of a prior art design having the drawbacks mentioned above is Beath et al., Patent Number 4,449,615, which discloses a nail device driven by a lever mounted on the floor. Many components in this design complicate it in comparison with the present invention. Beath uses a metallic ring design. During certain conditions, such as a hydraulic pressure failure, the metal rings will fall down and wedge between a fixed housing and the ram of an elevator. The friction generated by the downward movement of the ram in contact with the metal rings causes the metal rings to be driven downwards. As this occurs, the metal rings are wedged against the ram. The contact between the metal rings and the ram generates a frictional force which decreases the ram and finally becomes large enough to stop the downward movement of the ram. The force required to stop an elevator using a brake described in Beath exceeds the elastic limit of the material used in commercial rams. As mentioned before, this causes the ram to deform into an hourglass shape at the point where the metal rings hold the ram. Regarding the importance of braking systems having a relatively low profile, the abovementioned patent does not show precisely the relationship of the system with the upper part of the cylinder and the lower part of the elevator. However, it seems too high to fit into most existing elevator systems. Based on the problems discussed above and exemplified by patent number 4,449,615, a new elevator brake is needed that can safely stop a fully loaded elevator without permanently damaging the ram. A control system is also needed for such a new elevator brake.

BRIEF DESCRIPTION OF THE INVENTION The general objective of the present invention is to provide a mechanism for braking an elevator which safely holds a fully loaded elevator without permanently damaging any part of the elevator. Another object of the present invention is to provide an elevator suppressor that allows the elevator to be usable in a short period of time, with few readjustments and necessary repairs. Optimally, the readjustment and repair procedure can be relatively simple and inexpensive. Another object of the present invention is to provide a suppressor that is placed within a small vertical space so that it can be adjusted within the normal design parameters for hydraulic rammers and that can also be upgraded in existing hydraulic ram elevators. Another additional objective of the present invention is to provide a system that can be easily installed and that requires little downtime in which the elevator does not work. A further objective of the present invention is to provide a braking system that is inexpensive to manufacture. A further object of the invention is to provide a controller and a control algorithm for a suppressor or brake of the kind described herein.

A presently preferred embodiment of the invention provides a hydraulic brake system for braking and stopping a ram, jack or other cylindrical object. The preferred embodiment uses two lever-operated brake arms. These brake arms are aligned with a material that is softer than the material from which the ram or similar device is constructed. For example, the coating material may have a lower Brinell hardness number and / or a lower yield strength than the ram. The coating material is machined within the brake arms to a diameter slightly smaller than the diameter of the ram. When actuated, the brake arms and their respective cladding material contact the ram circumferentially, elastically pressing the ram and thereby generate a frictional force as the ram is elastically deformed. Due to the forces generated from the friction and the elastic tightening of the ram, its speed decreases and finally stops in its downward movement. Because most, if not all, deformations of the ram are elastic, the ram is not deformed substantially during this process. Because the present invention uses a material that is softer than the ram to apply a braking force, it is a clear improvement over the prior art. Preferably, this relatively soft material is copper and the ram is made of steel. The present invention is also relatively simple and has a low profile. This facilitates installation in current elevator designs. Preferably, the brake system also has reinforcing members, pivot bolts and a base plate. The pivot bolts connect the brake arms to the reinforcing members. Additionally, the brake arms are also mounted to the base plate. The brake arms can be mechanically driven by hydraulic pressure losses, an electronic signal from a hydraulic pressure detector, a downward overspeed detector or an uncontrolled down motion detector. In preferred embodiments, the force applied by the braking action is transferred from the brake arms through the base plate and its associated support structures. This structure can absorb the energy without damage or deformation and without any modification. By monitoring the pressure and overspeed, you can limit the fall of the elevator at speeds with a maximum of less than twice the normal downward speed, so that the kinetic energy produced is limited, by not allowing the elevator to fall freely. According to another aspect of the present invention, there is provided a system for non-destructively capturing a hydraulic piston in elevators, and such system includes a single controller for controlling its operation. Additionally, this system includes a detection system and an actuator. The detection system continuously detects the speed of the elevator and the direction of movement of the elevator. After detecting these parameters, the detection system generates an electrical signal corresponding to the detected speed and direction and sends the signal to the controller. The controller may be a CPU which may be programmed to compare the detected speed and direction of movement with a limited speed limit and direction of movement. If the detected speed exceeds the entered speed limit and the elevator moves in a downward direction, the controller generates a signal which is sent to the actuator. Upon receipt of the signal, the actuator causes the brake arms to suppress the movement of the ram. Other features of the present invention are described below, and others will undoubtedly occur to those familiar with the art upon reading and understanding the following detailed description, together with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is an elevation view showing the brake and control components, according to a preferred embodiment of the invention.

Figure 2 is a front elevation view of the preferred embodiment shown in Figure 1. Figure 3 is a sectional view showing the frictional contact and the position of the package according to the preferred embodiment shown in Figure 1. Figure 4 is a plan view of the preferred embodiment shown in Figure 1, when viewed along the line 4-4. Figure 5 is a sectional view of the brake and control components, according to another preferred embodiment of this invention. Figure 6 is a schematic view of a control system according to a preferred embodiment of this invention. Figure 7 is an isometric view of a control system according to another preferred embodiment of this invention. Figures 8-8E are collectively a flow chart illustrating the operation of the controller of Figure 7 according to a preferred embodiment of this invention. Figure 9 is a schematic view of the control system shown in Figure 7. Figure 10 is an isometric view of a control system according to another preferred embodiment of this invention.

DETAILED DESCRIPTION OF THE PREFERRED MODALITIES The drawings show a safety brake system according to the present invention, generally indicated with the reference number 1. Although the brake system 1 is applicable to many hydraulic ram or piston devices, it is described here in its preferred use in a lift by hydraulic ram. The references to "up", "down", "vertical", "horizontal", etc., should be understood to refer generally to the relative positions of the components of the illustrated device, which can otherwise be oriented or placed in different directions. Furthermore, although the term "hydraulic" is used, this invention can also be used with any device with a similar configuration, that is, a main cylinder surrounding a second cylinder. References to "hydraulic" should be understood to refer generally to any pressure ram device that includes, but is not limited to, hydraulic and pneumatic ram devices. In Figure 1, a reciprocating piston or ram 3 with a brake system 1 installed on the existing main cylinder 5 is shown. The spacer ring 7 rests on the upper end of the main cylinder 5 and is removably attached to the upper end of the main cylinder 5 by any of numerous known fastening means. In a preferred embodiment, the known fastening means comprises a plurality of openings 11 fixed to the outer surface of the main cylinder 5 near its upper end. Each opening 11 comprises a pair of flanges 13 fixed by welding or other means similar to the main cylinder 5 and spaced a short distance apart. Additionally, the openings 11 include a plurality of flanges 17 fixed to the exterior of the spacer ring 7. Both the flanges 17 and the flanges 13 have bolt holes. By aligning the bolt holes and connecting them with the opening bolt 20, the spacer ring 7 is made to coincide with the main cylinder 5, as best seen in Figure 4. Although in Figure 4 three openings 11 and their flanges are shown 13, 17 associated, it will be appreciated that a braking system of this invention may have any number of these openings 11. In an alternative embodiment, the openings 11 may comprise only a single flange. The advantage of using openings 11 is that any of the openings 11 can act as a pivot to rotate the braking system 11 away from the main cylinder 5 to allow access for service when the opening bolts 20 are removed from the other openings. For example, as shown in Figure 3 and as discussed below in greater detail, the main cylinder 5 may have a package 16 installed to prevent oil leakage. It is not uncommon for this pack 16 to be periodically replaced. By removing all the opening bolts 20 except 1, the spacer ring 7 and the brake system 1 can be pivoted about the installed opening bolt 20 to access the package 16 for repair or replacement. Additionally, the removal of all the opening bolts 20 will allow the total removal of the brake system 1 for greater work. If all the bolts 20 are removed, the device can be easily rotated to access the package 16 without the need to disconnect the electrical wiring or the hydraulic connections. The openings 11 also facilitate an adequate alignment of the brake system and the main cylinder 5 when they are matched. Given the generally small distance from the bottom of the standard hydraulic lifter to the top of the existing piston cylinder structure, a low profile device is desirable. The present device in its ready position is at a height of 10 and 13 cm (4-5 inches). This is accomplished by maintaining a fulcrum angle, the angle between the brake arms 27 and the base plate 21, at 15 degrees, as shown in the drawings, and as best seen in Figure 2. Due to that this system is of a low profile construction, it is easily mounted on all the existing elevator cylinders. The package 16 shown in Figure 3 varies from one elevator to another depending on the manufacturer. The length of the separator ring 7 depends on the type of packaging 16 used. In general, the gasket 16 is located in the cylinder part in the upper part of the cylinder 5, the gasket 16 is the seal which retains the oil pressure between the main cylinder 5 and the ram 3. Oil is used in such a way that a relatively smooth ram 3 slides relatively freely in and out of the main cylinder 5. Generally, there is some derivation of oil through this seal. When this derivative oil is excessive, the packing is usually changed as described above. The base plate 21 is fixed to the upper surface of the spacer ring 7. The reinforcing members 25 are fixed to the base plate 21. In the preferred embodiment, the brake arms 27 are hingedly fixed to the reinforcing members 25 by pivot bolts 29 which allow the brake arms 27 to rotate in and out of contact with the ram 3, as best shown in FIGS. Figures 1 and 2. Although the presently preferred embodiment uses two brake arms 27, a multiplicity of brake arms can be used. Each of the brake arms may take the form of a segment and may form a section of the ring around the ram 3. These sections may be of equal size, or they may be different, if desired. Sections sized differently may be advantageous in certain situations, including the time when the configuration of the workspace makes installation or maintenance easier for a certain portion of the brake system 1 that is more articulated. In its ready or standby position, the brake arms 27 are raised 15 degrees from the horizontal, which alla water displacing space 3, as best shown in Figure 2. The brake arms 27 they conform to have semicircular cutouts, as best seen in Figure 4, of a slightly larger diameter than the ram 3, and have a friction material 31 mounted within the cutouts. This frictional material can be a cumulative material or a non-cumulative material. A cumulative friction material is a material which causes friction by adding the friction material to the moving surface with which it contacts. This may involve actual transfer of material or "accretion" of the accumulative friction material on the moving surface. More specifically, the term "cumulative" can refer to the transfer of a softer material to a harder material. Therefore, in this invention, when the friction material 31 contacts the heavier material of the ram 3, 31 which is preferably made of steel, part of the frictional material 31 can be transferred to the ram 3. In addition, the frictional material 31 used in this invention preferably has an elastic limit and a Brinell hardness number which is less than that of the ram 3. By having a lower yield strength and a lower Brinell hardness number, the frictional material 31 acts as a sacrificial layer and yields before that the ram 3. This avoids the destructive damage of the ram 3. As discussed in more detail in the following, when the brake arms 27 are actuated, the frictional material 31 is circumferentially coupled to the ram 3. When the frictional material 31 does contact with the ram 3, a frictional force develops and the ram 3 is elastically pressed. The forces generated by the friction between these components and the elastic deformation of the ram 3 suppress the movement of the ram 3. Since the Brinell hardness number and the elastic limit of the ram 3 are greater than that of the frictional material 31, the contact between these components will not cause substantial permanent deformation of the ram 3. More specifically, the frictional material 31 will yield or scrape before the ram 3. Therefore, any scraping or non-elastic deformation occurring on the frictional material 31 and most of it in case not all the deformation of the ram 3 will be elastic. Consequently, the ram 3 does not deform substantially when the brake arms 27 are activated to suppress their movement. The precise reason why the ram 3 stops most probably can be attributed to one of two forces or the combination of these forces, the elastic compression force and the frictional force. As the ram deforms elastically due to elastic tightening, it changes its cross-sectional area. Since tension is inversely related to the area, as the area decreases during elastic deformation, tension increases. This increase in tension is significant and can be large enough, based on the size of the lifter, by itself without the frictional force stopping the movement of the ram. Stopping the movement of the elevator when tightening it elastically is important because it minimizes the effect that contaminants have on a stopping force. Pollutants such as hydraulic oil or the like may be interposed between the frictional material and the ram 3. If this occurs, the contact between the frictional material 31 and the ram 3 decreases and the frictional force also decreases. Potentially, the contaminants can reduce the frictional force to a point where it is not large enough to stop the movement of the ram 3. The elastic tightening force is not significantly affected by the presence of contaminants and therefore, by stopping the ram. with an elastic tightening force it has an advantage over the frictional force. In a preferred embodiment, the frictional material 31 is copper, but other materials can be used. Copper is preferred because, of the tested materials, they have the greatest tendency to adhere to the ram 3 and therefore maximize the amount of friction between the ram 3 and the brake lining 31. By maximizing the friction between these components, the highest braking force is generated with the least amount of damage / deformation to the ram 3 and braking system 1. In addition, its elastic limit and Brinell hardness number are sufficiently low compared to that of steel, so that the copper will experience non-elastic deformation or scraping before the ram. In addition, the Brinell hardness number and the elastic deformation of the copper are sufficiently high so that they can provide adequate braking force without failure and without permanently deforming the ram. If these properties are too low, then the frictional material will not be able to provide the necessary braking force. Copper has sufficient resistance to fatigue so that it will not fail after a few cycles. The inner diameter of the cycle formed by the frictional material 31 is slightly smaller than the outer diameter of the ram 3. This provides an appropriate coupling with the ram 3 to cause the elevator to stop. In an alternative embodiment of the brake arm, illustrated in FIG. 5, projections or cutting teeth 66 can be fixed to the friction material mounting surface 28 of the brake arms 27 instead of or in addition to the frictional material 31. In this embodiment, the braking is carried out by the teeth that impinge on the ram 3. Unlike the hourglass damage caused by the prior art, the type of damage caused in this mode can be repaired by filling and filing. the stretch marks. Other systems for articulably fixing the brake arms 27 to the reinforcing members 25 are possible. In an alternative mode of articulation, joint bolts can be used. In the articulated bolt mode, not shown, the rear side of the brake arms 27 opposite the semicircular cutouts are oriented against the reinforcing members 25 instead of being placed therebetween as in the preferred embodiment. The brake arms 27 are spaced apart from the reinforcing members 25 a sufficient distance so that the brake arms 27 rotate upwards 15 degrees with respect to the horizontal. A plurality of articulation bolts pass through the holes in the reinforcing member 25 within the trailing edge of the brake arms 27 and are threadably attached thereto. The bending of the hinge pins allows the pivotal movement of the brake arms 27. In another alternative embodiment of articulation that is also not shown, a slidable joint may be used. In this alternative embodiment, the side of the brake arms 27 opposite the closest side of the ram 3, again, is oriented against the reinforcing members 25 instead of being placed between them. The reinforcing members 25 may have a concave channel to partially receive the trailing edge of the brake arms 27 and the trailing edges of the brake arms 27 are rounded to place the concave surface of the reinforcing members 25. During the pivotal movement of the brake arms 27, the rounded rear edges and the brake arms 27 slide within the concave surface of the reinforcing member 25. Figure 3 shows the brake system 1 in its actuated position. The friction material 31 is in circumferential contact with the ram 3. A horizontal downward movement of the brake arms 27 is prevented by contact with the base plate 21. The separating ring 7 transfers kinetic energy from the brake arms 27 and the base plate 21 onto the main cylinder 5 or any associated support structure which may exist. The openings 11 and the structural strength of the spacer ring 7 prevent the brake system 1 from slipping and ensure an approximately equal transfer of downwardly directed force to the existing main cylinder 5 or to any associated cylinder support structure. The kinetic energies can be limited by limiting the permitted downward speed before the brake system 1 is actuated, thereby avoiding damage to the brake system 1, ram 3 or main cylinder 5. The hydraulic actuation of the brake arms 27 is carried out by the hydraulic drive assembly 38. The hydraulic drive assembly 38 includes a feedback control cylinder 43 and a drive rod 35. The upper part of the actuating rod 35 has a rectangular metal disk or wafer 37 which is received inside gaps or grooves formed in the brake arms 27. As best shown in Figure 1, the feedback control cylinder 43 is fixed between the upper hydraulic cylinder clamp arm 46 and the lower hydraulic cylinder clamp arm 48 of the hydraulic cylinder clamp 55. The clamp arms 46, 48 are fixed to the hydraulic cylinder clamp 55, which is fixed to the spacer ring 7. The feedback cylinder 43 has a hole for receiving the lower end of the drive rod 35, a plunger 47 fixed to the lower end of the drive rod 35 and a helical compression spring 45, as best shown in Figure 1. The helical compression ring 45 engages on and around the lower end of the drive rod 35, and is compressed between the inner surface of the upper part of the feedback cylinder 43 and the other end of the coupling piston 47. Pressurized fluid such as hydraulic oil is transmitted from the main cylinder 5 through the hose 49 to the feedback cylinder 43. The helical compression return spring 45 drives the plunger 47, and to the drive rod 35 fixed thereto, downwards. Under normal conditions, the pressurized fluid in the feedback cylinder 43 overcomes the energy of the compressed spring of the return spring 45 and urges the plunger 47 upwards, which in turn drives up the control rod 35, which then urges the brake arms 27 to a ready or standby position. The loss of hydraulic pressure in the main cylinder 5 is communicated to the feedback cylinder 43 through the hose 49 (Figures 1 and 2). If this happens, the return spring 45 overcomes the reduced pressure of the feedback cylinder 43 by driving the plunger 47 and the drive rod 35 attached downward and thereby pulling the brake arms 27 into contact with the ram 3. , as shown in Figure 3. The friction resulting from contact of the frictional material 31 with the ram 3 drives the brake arms 27 further down in contact with the ram 3, until the brake arms 27 and rest on the horizontal base plate 21. As this occurs, the friction material 31 of the brake arms 27 is frictionally coupled to the ram 3 and elastically compresses the ram 3 with sufficient force to stop the downward movement of the ram 3. Almost most of the deformation of the ram 3 it is elastic, and preferably all of it is elastic, although a slight amount of plastic deformation may occur.

Therefore, the frictional force and elastic compression of the ram 3 retain the movement of the ram 3. As shown in Fig. 1, the electronic actuation of the brake arms 27 can be carried out by a drive assembly 40 The electrode is rigidly fixed to the separating ring 7 by a control clamp 57, an upper solenoid clamp arm 61 and a lower solenoid clamp arm 63. The electronic drive assembly 40 comprises an electronic trigger rod 59 and a helical compression support spring 51 positioned on and around the electronic drive rod 59. The upper end of the support spring 51 engages the lower surface of the hydraulic control assembly 38, and the lower end of the support ring 51 engages the upper surface of the solenoid bracket 61. In this preferred embodiment, the electronic trigger rod 59 is fixed at its upper end and, generally, to the hydraulic drive assembly 38. As best seen in Fig. 1, the hydraulic activation assembly 38 is mounted on the clamp 55 which may be a slidable clamp. The clamp 55, for example, can be fixed to the control clamp 57, so that it can be slid or moved either in an upward or downward direction. The solenoid helical compression support ring 51 is selected to support the weight of the brake arms 27 and the hydraulic drive assembly 38. The tubular solenoid 65 is mounted on the control assembly 40 which is fixed between the upper and lower solenoid clamp arms 61 and 66. The lower end of the electronic actuator rod 59 partially penetrates the tubular solenoid 65 as best shown in FIGS. 3 and 5. The upper end of the electronic actuator rod 59 is coupled to the underside of the cylinder clamp arm 48. lower hydraulic An electronic signal from a descending overspeed detector 302, an uncontrolled downward motion detector 301, shown schematically in Figure 6, causes an electric current in the solenoid 65. This current generates a magnetic field of sufficient force to drive the rod 59 of electronic drive and downwardly within the tubular solenoid 65, whereby it pulls the entire hydraulic drive assembly 38 downwardly. Since the assembly 38 is attached to the brake arms 27, they are actuated when the assembly 38 moves in the downward direction. In an alternative mode, not shown, the assembly 40 of electric drive is the same as described above, except that the hydraulic drive assembly 38 is not used. Instead, the electronic drive rod 59 engages directly with the brake arms 27. In this embodiment, an electronic signal from a hydraulic pressure detector can also be used to drive the electronic drive assembly 40, in addition to a downward overspeed or uncontrolled downward movement detector. A schematic view of a control system 98 using the electronic drive assembly 40 is shown in Figure 6. This system includes either or both of the overspeed detector 302 and / or an uncontrolled downward motion detector 301, a controller 303 , the electronic drive assembly 40, the hydraulic drive assembly 38 and a brake system 1. A variety of known downstream overspeed detectors or uncontrolled downward motion detectors are available for use for this invention. For example, these devices may include those described in Coy, patent number 4,638,888, which describes an electronic system for detecting hydraulic pressure in a ram ram cylinder., and Ericson, patent number 5,052,523 and Sobat, patent number 3,942,607, which describe mechanical means for detecting the downward velocity of an elevator. The specifications of these patents are incorporated herein by reference in their entirety. The details of the other components have been described in the above. In this system, the detector 302 and / or the sensor 301 determine whether any of its respective conditions are present. If any of the conditions is present, this information is input to the controller 303. The controller 303 generates a signal in response to these conditions to activate the solenoid 65 of the electronic drive assembly 40. In response, the solenoid 65 communicates with the hydraulic drive assembly 38, and the hydraulic drive assembly 38 operates the brake system 1 to stop the ram 5 and the elevator 120. The details of these operations are described above. Despite the availability of known control systems, a further aspect of the present invention is to provide an improved control system 98. Such a control system 98 is described with reference to Figures 7 and 8-8E and includes a detection system 100, a controller 102 and an operation mechanism 104. The detection system 100 includes a pair of pulleys 106, 108, an electric generator 110 and a wire rope 112 attached to an elevator 120 by conventional means, such as sleeves 114 cable, springs 116 and fasteners 118. Figure 7 an isometric view of a preferred embodiment of this control system 98. Although this figure does not show all the components of the brake system 1, the ram 3 and the main cylinder 5 described above, it will be appreciated that they can be used with this control system 98. For example, the main cylinder 5 and the feedback cylinder 43 are shown in Figure 7. However, the orientation of these components to each other is different in Figure 7 only for illustrative purposes and can be configured as shown in the figures 1 to 5. Further, it will be understood that although the ram 3 and lifter 120 are not mechanically connected in Figure 7, these components are mechanically connected in a conventional manner so that the movement of the ram 3 causes movement of the lifter 120. Again, the mechanical connection between these components is not illustrated in Figure 7, so that other aspects of the control system 98 can be explained more clearly. As shown in Figure 7, the wire rope 112 is attached to the top and bottom of an elevator 120 and runs on the pulleys 106, 108. In this embodiment, the upper pulley is a free pulley 106 and the lower pulley it is a free pulley 108. In operation as the elevator 120 moves up and down, the cable 112 moves with the elevator 120 and causes the pulleys 106, 108 to rotate. As the driving pulley 108 rotates, it interacts with the electric generator 110, which preferably is an encoder or similar device for converting the rotation of the driving pulley 108 to electrical pulses and an electrical signal corresponding to the rotation speed of the pulley 108 driven. Because the movement of the elevator 120 controls the speed of rotation of the driving pulley 108, the signal generated by the encoder 110 s indicative of the speed of the elevator. The number of pulses varies with the rotation speed of the driving pulley 108. If the encoder has two phases, then one phase is used to indicate the speed of the elevator and the other is used to indicate the direction of movement of the elevator. Specifically, the second phase generates a signal that varies with the direction of rotation of the driving pulley 108 and therefore, with the direction of movement of the elevator 120. The encoder 110 or similar device is preferably wired to the controller 102 shown in the figure 7. The controller 102 preferably has a central processing unit (CPU) that functions as described in the following to activate the brake system 1 if the speed of the elevator 120 exceeds a predetermined speed limit. In general terms, the controller 102 is programmed to control the actual movement of the elevator with the desired movement. If certain conditions are present, for example that the elevator speed exceeds an entered speed limit or the displacement in a direction other than the direction of travel considered, the controller 102 activates the operation mechanism 104 to operate the brakes. The CPU has two independent drive circuits to ensure that, if one fails, there is a fail-safe circuit. In addition, the controller 102 may be driven by a battery 130 or a source 132 of external electrical power. Preferably, the controller 102 has a switch 134 that can be operated to adjust a speed limit for the elevator. The switch 134 may be any of numerous conventional electrical switches, such as a DIP switch. An actuator 122 is included within the operating mechanism 104. In the preferred embodiment illustrated in FIG. 7, the actuator is a pair of solenoids operated by three-way valves. Two valves are used for redundancy purposes, however, a valve can be used. The valves are connected in series by conduits 121 or similar connection devices between the main cylinder 5 and the feedback cylinder 43. Each of the valves has three holes. A first orifice 124 connects the valves to the main cylinder 5, a second 126 to the feedback cylinder 43 and the third 128 to a buffer area, such as a tank (not shown). Since the valves are solenoid operated valves, they can be positioned to connect any two of these holes together in response to an electrical signal. In a first position, the third hole 128 is closed in each of the valves and hydraulic fluid is sent from the main cylinder 5 to the feedback cylinder 43. As discussed in the foregoing, when pressurized fluid is sent to the feedback cylinder 43, the brake system 1 is in its raised position and the ram 3 is free to move in and out of the main cylinder 5. The controller 102 generates a signal in response to the detected emergency condition, and this signal is sent to the valves. The valves are then repositioned to allow fluid flow from the second orifice 126 to the third orifice 128. In this position, the fluid can not flow from the main cylinder 5 to the feedback cylinder. Therefore, in this position, the feedback cylinder 43 is vented and not pressurized. This causes the brake arms 27 to act as described above in detail. If any valve is repositioned in response to the signal generated by the controller 102, the feedback cylinder 43 will be ventilated and activated to the brake system 1. Consequently, the use of two valves provides a safety feature that protects against valve failure. Figure 10 illustrates another preferred embodiment of the control system 98. This embodiment shown in Figure 10 is similar to that described with reference to Figure 7, except that operation mechanism 104 differs. Specifically, in this embodiment, the operation mechanism is a multiple, as opposed to the valves and the feedback cylinder described above. Within the manifold there may be a valve or orifice connecting the main cylinder 5 with a hydraulic pressure source for the hydraulic actuator assembly 38. The position of this valve or orifice can be relocated by the controller 102 to stop the flow from the main cylinder 5 to the hydraulic pressure source, and then another valve or orifice can be placed to vent the source of pressure. As the pressure source decreases, the pressure in the hydraulic feedback assembly 38 decreases and the brake is activated as described above. In Figure 9 a schematic diagram of a preferred embodiment of this control system 98 is illustrated. As shown in this figure, the controller 102 receives inputs including the actual speed 306 and the actual elevator travel direction 304, and a desired speed 305 and a desired elevator travel direction 309. Additionally, the controller 102 receives inputs from the elevator coil 307 and the lower coil 308 of the elevator. As is well known in the art, these coils are respectively energized to move the elevator in an upward or downward direction. By comparing the desired inputs 305, 309, and the status of the coils 307, 308 to the current inputs 306, 304 the controller 102 determines whether an emergency condition is present. The specific details of the operation of the controller 102 are provided below. If such a condition is present, the controller 102 activates the operation mechanism 104. The operation mechanism 104 drives the hydraulic drive assembly 38, which operates the brake system 1, as described above. Additionally, the controller 102 may receive either or both auditory and / or visual alarms 310.

As shown in Figures 8-8E, the CPU of this invention can be programmed to control the brake system if one of several conditions occurs. For example, the braking device can be activated without the elevator speed in the downward direction exceeding a certain predetermined limit.

As mentioned before, the CPU is contained within the controller 102 and has several outputs. For example, you can illuminate lights and alarm sounds that are indicative of an alarm condition or a maintenance condition. Alarm conditions may include moving the elevator at an excessive speed or in the wrong direction. As is typical of computer programs, the program begins by initializing itself (step 140).

While the CPU performs the initialization program, it can illuminate a display indicating that it is executing this portion of the program (step 142). During the initialization process, the CPU can determine if a "warning condition" exists (stage 144). Warning conditions may include a blown or "blown" fuse, low level battery or loss and / or the number of instances in which the brakes have been operated, a brake cycle, exceeding a predetermined cycle limit. Brake. Because after a certain number of cycles, the frictional material may have been eroded, a limit is set for the number of cycles that the brake can last before the frictional material is verified and / or replaced. If any of these warning conditions are present, the CPU can activate an audible alarm or activate a brake (step 145). If a warning condition is not found, the CPU can calculate the maximum speed for the elevator (step 148) and display indications that the systems are functioning (step 150). These indications can be lights, impressions or other similar indication. This speed can be calculated by receiving inputs from an elevator with a device such as a DIP switch, indicated with the reference number 134 in Figure 7, or a similar device. The controller 102 may also receive inputs from a test device (not shown) commonly known as a service tool, which may be used to test the operation of the CPU. Such a device includes a numeric keypad and an LCD screen and can be operated remotely by connecting the tool to the controller with a serial cable. The service tool is used to input signals to the CPU and verify its response to the signals to ensure that it functions properly. After calculating the maximum speed for the elevator, the program receives inputs (step 152) from the coils (not shown) that control the movement of the elevator. Typically, an elevator has an upper coil and a lower coil that are electronically energized to respectively move the elevator in either an upward or a downward direction. After receiving these inputs, the CPU selects one of the subroutines corresponding to the state of the coils, either a lower coil subroutine if the lower coils are energized (step 154), an upper coil subroutine (step 156) if energize the upper coils, or a static service mode subroutine (step 158) if none of the coils is energized. In the lower coil subroutine (step 154), the input is received from the coder 110 (step 160). The CPU then analyzes whether the speed signal received from the encoder is indicative of a speed approximately equal to zero. If the speed is approximately equal to zero, this indicates a problem with the system and the brake is activated (step 164, 166). For example, the 110 encoding may have failed. This condition is indicative of a problem because the lower coil has been energized, and when the lower coil is energized the elevator must be moving relatively fast. Consequently, if the indicated speed is approximately zero, then there is a problem and the brake must be activated. If the speed is not approximately equal to zero, the CPU determines if there is an address error, a battery fault or a fault in the encoder (step 163). If such a fault exists, the brake is activated (step 165). If no fault is found, the CPU checks the speed and direction of the elevator indicated by the encoder (step 167). After making these checks, the CPU evaluates whether the elevator 120 is moving in the downward direction as it should do since the lower coils are energized. If the encoder 110 indicates that the elevator is traveling in the upward direction (167a), this indicates a problem and the CPU generates an address alarm signal and activates an audible alarm (step 168). Additionally, the program executes the subroutine 210 of the system state. If the elevator 120 is not moving in the upward direction, the CPU then compares the indicated speed with the speed limit (step 170). If the speed limit is exceeded, the CPU generates a signal to operate the brake (step 172). In comparison, if the speed is less than or equal to the speed limit, the CPU then determines whether the speed of the elevator 120 is in the service area when evaluating whether the elevator speed is relatively low (step 174). Since typically an elevator does not travel at a relatively low speed, a relatively low speed is indicative that the elevator requires service or is in a maintenance condition. If the speed is in the service area, the CPU determines if the coils are energized or if the elevator is still in service mode (step 152). Conversely, if the elevator speed is not in the service area, the speed and direction are again checked (step 167), and the steps described above are performed repetitively. If the CPU determines that the coils are energized, it will execute the upper coil subroutine, as shown in Figures 8B, 8D and 8E (step 156). Similar to the lower coil subroutine (step 154), the upper coil subroutine (step 156) inputs the elevator speed indicated by the coder (step 176) and determines if the indicated speed is approximately equal to zero (step 178). Similar to the previous description with reference to the lower coil, if the indicated speed is approximately equal to zero, this indicates a problem because the upper coil is energized and the elevator must be moving. Therefore, if the indicated speed is approximately equal to zero, an encoder failure can be indicated and an audible alarm is sounded (step 180). After sounding the alarm, the CPU executes step 152 to determine the state of the coils. If the speed is not approximately equal to zero, the CPU checks the operation of the encoder (step 182). If a fault is detected in the encoder, the CPU sounds an alarm (step 184) and re-executes step 152 to determine the state of the coils. After it is determined that the encoder 110 operates properly, the CPU checks the direction of travel and the speed of the elevator 120 as indicated by the encoder (step 186) and determines whether the direction of travel that is entered is in the direction of above (stage 188). If the elevator 120 is not moving in the upward direction, the CPU sends a wrong address alarm (step 190) and compares the elevator speed 120 (step 192) with the service speed. If the elevator speed exceeds the service speed, the CPU activates the brake system (step 194). However, if the elevator is moving in an upward direction or service speed has not been exceeded, the program executes the system state subroutine (step 210) as described below. When none of the coils has been energized, this indicates that the elevator 120 must be static and that the static service mode subroutine is executed (step 158). In this subroutine (step 158) the CPU verifies (step 198) the speed and direction of travel. Specifically, the direction of movement in the upward direction is determined (step 202), the speed is evaluated to determine if it is approximately equal to zero (step 200) and it is evaluated whether the speed of the elevator 120 exceeds a service speed limit ( stage 204). If the elevator is moving upwards, the CPU checks the status of the coils again (step 152). If the elevator is not moving up, the CPU determines if the speed is approximately equal to zero (step 202). If it is not approximately equal to zero, the elevator speed is compared with the service speed (step 204). If the indicated speed is greater than the service speed, the brake is activated (step 206). Conversely, if the speed is approximately zero or is less than the service speed, the system state subroutine is executed (step 210). The system state subroutine (step 210) is executed if it is discussed earlier if: (1) an address error is indicated; (2) the elevator 120 moves upward at a speed that is not approximately equal to zero with the upper coil energized; or (3) the elevator moves up when the upper coil is energized and is moving at a speed lower than the service speed. In this subroutine (step 210) the CPU determines if any of the parameters has changed (step 212). If the state of the system has changed, check the system parameters again (step 213), before determining if the set point in terms of speed has changed (step 214). If the set speed point has changed, a new maximum speed limit is calculated (step 215). After determining that the set speed point has not changed or after calculating a new speed limit, the CPU is then evaluated if any of the warning flags are present (step 216). Warning flags may include a lost or "blown" fuse, low-level battery or loss of the number of braking cycles that exceed a predetermined limit, as discussed above, and / or one or both drivers for the controller do not work properly. If no warning flags are detected, the CPU transmits diagnostic information to a typical screen format for evaluation (step 218). If the warning flags are present, the CPU processes and displays these warnings in a conventional manner, for example by lights or printed information (step 217) and displays diagnostic information (step 218). After displaying diagnostic information (step 218), the state of the coils is reevaluated (step 152). A system of this type can be updated for existing elevators, which makes it desirable not only to establish an emergency brake but also to monitor less dangerous and equally important conditions. For example, a common modern technique of scanning the exact positions of floor levels can be incorporated. The update of "level off" of information to the elevator controller warns the entry and exit of passengers from danger, or inhibits the operation of the doors in any way. In addition, on speed conditions in the downward direction which can not be caused by a fault, but due to an overload, an output signal aimed at braking the elevator is detected and implemented. National, state and local codes provide regulations for periodic testing of safety devices, so it is desirable to re-test whether you damaged either the ram or the brake. Prototype tests to date have shown a deformation of less than 0.508 μm (20 thousandths of an inch) of the copper at the open edges of the copper rod, where the brakes make contact centrally when they close, and without deformations in the others parts. Preferred embodiments described herein are illustrative only and, although the examples provided include many specificities, they are considered as illustrative of only one possible embodiment of the invention. Undoubtedly, other modalities and modifications will occur to those familiar with the technique. Therefore, the examples that are provided only should be construed as illustrations of some preferred embodiments of the invention, and the full scope of the invention should be determined by the appended claims and their legal equivalents.

Claims (24)

REVIVITIONS

1. A safety brake system for a hydraulic lift that has an elevator car attached to a ram to move the car in response to the selective application of hydraulic fluid to an associated cylinder and a brake to couple the ram and prevent movement of the car. of elevator, the safety brake system comprises: a brake that has pivotally mounted a pair of brake arms, each has a friction material mounted thereon, the brake arms and the friction material are shaped to couple circumferentially with the outside surface of the ram; a brake operating mechanism connected to the brake arms for rotating the brake arms between a ready position, without coupling to the ram, and a driven position, in engagement with the ram; a source of an electrical signal representing an operating condition of a hydraulic lift car connected to the ram; and a brake controller connected between the signal source and the brake operating mechanism so that, when the brake is installed on a hydraulic lift system, one of the operating mechanism and the brake controller responds to a normal hydraulic pressure in a cylinder associated with the ram to keep the brake in the ready position, and responding to a loss of normal hydraulic pressure to move the brake to the actuated position, the brake controller responds to the electrical signal to move the brake to the driven position when the electrical signal represents a predetermined operating condition of the elevator car.

2. The safety brake system according to claim 1, wherein the brake operating mechanism includes a hydraulically actuated assembly connected with the brake arms and adapted to be in fluid communication with the cylinder so that the assembly of The hydraulic actuator responds to the normal hydraulic pressure in the cylinder to keep the brake in the ready position, and responds to a loss of normal hydraulic pressure to move the brake to an actuated position.

3. The safety brake system according to claim 2, wherein the controller includes an electrical drive assembly connected to the hydraulic drive assembly, whereby the electrical drive assembly responds to an electrical signal to drive the hydraulic drive to move the brake to the driven position when the electrical signal represents the predetermined operating condition of the lift car.

4. The safety brake system according to claim 3, wherein the brake operating mechanism includes an actuator adapted to be in fluid communication with the cylinder and which is in fluid communication with the hydraulic actuator assembly, the controller of Brake is connected to the actuator to control the actuator and prevent fluid flow to the hydraulic actuator assembly whereby the brake is moved to the actuated position when the electrical signal represents the predetermined operating condition of the elevator car.

5. The safety brake system according to claim 1, wherein the brake controller includes an electrical drive assembly connected to the brake arms by the brake operating mechanism and responding to a pressure signal representing pressure of fluid in the cylinder so the electrical drive assembly responds to the pressure signal representing a normal hydraulic pressure in the cylinder to keep the brake in a ready position and responding to a pressure signal representing a loss of the normal hydraulic pressure to move the brake to the driven position.

6. The safety brake system according to claim 1, wherein the brake controller includes an electric drive assembly connected to the brake arms by the brake operating mechanism and a sensor connected to the electric drive assembly to generate the electrical signal.

7. The safety brake system according to claim 6, wherein the sensor is an uncontrolled down motion detector.

8. The safety brake system according to claim 6, wherein the sensor is a real steering sensor and the electrical drive assembly compares the electrical signal with a signal representing a desired direction of travel of the lift car.

9. The safety brake system according to claim 6, wherein the sensor is a downward overspeed detector.

10. The safety brake system according to claim 6, wherein the sensor is a real speed sensor and the electrical drive assembly compares the electrical signal with a signal representing a desired speed of the elevator car.

11. A safety brake system for a hydraulic lift that has an elevator car attached to a ram to move the car in response to the selective application of hydraulic fluid to an associated cylinder and a brake to couple the ram and prevent movement of the car. of elevator, the safety brake system comprises: a brake having a pivotally mounted pair of brake arms, each having a friction material mounted thereon, the friction material having a Brinell hardness number less than the number Brinell hardness of the material forming an outer surface of a hydraulic lift ram of a hydraulic lift system, the brake arms and the friction material are shaped to be circumferentially coupled to the outer surface of the ram; a brake operating mechanism connected to the brake arms for pivoting the brake arms between a ready position, without coupling to the ram, and a driven position, in engagement with the ram; a source of an electrical signal representing an operating condition of a hydraulic lift car connected to the ram; and a brake controller connected between the signal source and the brake operating mechanism so that, when the brake is installed on a hydraulic elevator system, one of the brake operating mechanism and the brake controller responds to a normal hydraulic pressure in a cylinder associated with the ram to keep the brake in the ready position, and responding to a loss of normal hydraulic pressure to move the brake to the actuated position, the brake controller responds to the electrical signal to move the brake to the actuated position when the electrical signal represents a predetermined operating condition of the elevator car.

12. The safety brake system according to claim 11, wherein the friction material is copper.

13. The safety brake system for upgrading an existing hydraulic lift that has an elevator car attached to a ram to move the car in response to the selective application of hydraulic fluid to an associated cylinder, the safety brake system comprises: a ring separator adapted to be mounted on an upper end of a hydraulic lifting cylinder; a brake having a pair of brake arms mounted pivotally on the spacer ring, each brake arm having a friction material mounted thereon, the brake arms and the friction material are shaped to be circumferentially coupled to the outer surface of the brake arm. ram; a brake operating mechanism connected to the brake arms to move the brake arms between a ready position, without coupling with the ram, and a driven position, in engagement with the ram; a sensor for generating an electrical signal representing an operating condition of a hydraulic lift car connected to the ram; and a brake controller connected between the signal source and the brake operation mechanism so thatWhen the brake safety system is installed on the hydraulic lift system, either the brake operation mechanism or the brake controller responds to a normal hydraulic pressure in a cylinder to keep the brake in its ready position and that responds to a loss of normal hydraulic pressure to move the brake to the actuated position, the brake controller responds to the electrical signal to move the brake to the actuated position when the electric signal represents a predetermined operating condition of the elevator car.

14. The brake safety brake system according to claim 13, wherein the brake operating mechanism and the brake controller are mounted on the separator ring.

15. The brake safety brake system according to claim 13, wherein the brake operating mechanism includes a hydraulically actuated assembly connected to the brake arms and adapted to be in fluid communication with the cylinder, so that the hydraulic drive assembly responds to a normal hydraulic pressure in the cylinder to keep the brake in the ready position and responds to a loss of normal hydraulic pressure to move the brake to the actuated position, and in which the brake controller it includes an electrical drive assembly connected to the hydraulic drive assembly whereby the electrical drive assembly responds to an electrical signal to drive the hydraulic drive assembly to move the brake to the actuated position when the electrical signal represents an operating condition default of the elevator car.

16. The safety brake system according to claim 13, wherein the brake controller includes an electrical drive assembly connected to the brake arms by the brake operating mechanism and which responds to a pressure signal representing pressure Fluid in the cylinder, so the electric drive assembly responds to the pressure signal representing normal hydraulic pressure in the cylinder to keep the brake in the ready position and responds to the pressure signal representing pressure loss Normal hydraulic to move the brake to the driven position.

17. The safety brake system according to claim 13, wherein the brake operating mechanism includes an actuator adapted to be in fluid communication with the cylinder and which is in fluid communication with the hydraulic actuator assembly, the controller of The brake is connected to an actuator to control the actuator and prevent fluid from flowing to the hydraulic actuator assembly whereby the brake is moved to the actuated position when the electrical signal represents a predetermined operating condition of the elevator car.

18. The brake safety brake system, according to claim 17, wherein the actuator includes a pair of solenoid-operated three-way valves connected in series, each of the valves is individually actuated by the brake controller for prevent fluid from flowing to the hydraulic drive assembly.

19. The brake safety brake system, according to claim 17, wherein the actuator includes a manifold that is actuated by the brake controller.

20. The brake safety brake system, according to claim 17, wherein the sensor is a speed sensor for generating an electrical signal representing a real speed of the elevator car.

21. The brake safety brake system according to claim 13, wherein the brake controller includes a CPU programmed to perform an initialization program to determine if the electrical signal represents a warning condition, the UPC responds to the electrical signal representing a warning condition for performing at least one of the movements of the brake to the actuated position and generating an alarm signal.

22. The brake safety brake system, according to claim 13, wherein the brake controller includes a UPC programmed to select and perform a higher coil subroutine when the electrical signal represents an upwardly moving direction for the car. of elevator, a downstream coil subroutine when the electrical signal represents a downward direction of travel for the lift car, and a service subroutine when the electrical signal does not represent any direction of travel for the lift car, the UPC verifies for at least one condition of operation of the elevator car for a problem during each of the subroutines and performs at least one of the movements of the brake to the actuated position and the generation of an alarm signal when a problem is detected.

23. The brake safety brake system, according to claim 22, wherein the UPC performs a service mode subroutine when a predetermined problem is detected and generates a signal representing diagnostic information for display.

24. The brake safety brake system, according to claim 22, wherein the UPC performs a system state subroutine when a predetermined problem is detected, and generates a signal representing diagnostic information for display. RESTJMTW? B T.A INVTÍWGTÓTJ The invention relates to a brake system for a hydraulic ram (3) or another cylinder, which can be used as an emergency brake for an uplift. When actuated, the brake arms (27) contact the ram circumferentially so as to brake and stop the ram that falls. The brake arms are preferably aligned with and made of a material that frictionally engages the ram to stop downward movement of the ram. The brake system can be operated by the loss of hydraulic pressure, by an electronic signal from a hydraulic pressure sensor, by a downward overspeed sensor (40) or by an uncontrolled down motion detector. According to another aspect of the present invention, a controller, which is preferably a programmed control system, compares the actual movement of the elevator detected by the detector with a desired movement. Under certain conditions, if the actual movement differs from the desired movement, the controller operates the brake.