The present disclosure is generally directed to composite elevator belts for use in lifting and lowering an elevator car. More particularly, the present disclosure is directed to composite elevator belts having a load carrier including one or more core layers, one or more load carrying strands embedded in the core layer, a plurality of teeth associated with the core layer, and one or more jackets at least partially covering the load carrier. The present disclosure is also directed to methods and apparatuses for making composite elevator belts.
Elevators for vertically transporting people and goods are an integral part of modern residential and commercial buildings. A typical elevator system includes one or more elevator cars raised and lowered by a hoist system. The hoist system typically includes both driven and idler sheave assemblies over which one or more tension members attached to the elevator car are driven. The elevator car is raised or lowered due to traction between the tension members and drive sheaves. A variety of tension member types, including wire rope, V-belts, flat belts, and chains, may be used, with the sheave assemblies having corresponding running surfaces to transmit tractive force between the tension members and the sheave assemblies.
A limiting factor in the design of current elevator systems is the minimum bend radius of the tension members. If a tension member is flexed beyond its minimum bend radius, the compressive forces within the tension member may exceed the breaking strength of the tension member material. Continuous operation of the tension members below their minimum bend radii can cause fatigue at an increased and unpredictable rate and, under extreme circumstances, may result in elastic deformation and failure. Thus, minimum size of the sheaves useable in an elevator system is governed by the minimum bend radius of the tension members. For several reasons, sheaves having a smaller diameter allow for more economical elevator system designs. First, the overall component cost of an elevator system can be significantly reduced by using smaller diameter sheaves and sheave assemblies. Second, smaller diameter sheaves reduce the motor torque necessary to drive the elevator system, thereby permitting use of smaller drive motors and allowing for smaller hoistway dimensions. Additionally, decreasing the bend radius of the tension members generally permits easier installation and decreases the spool size of the tension members.
Accordingly, minimizing the bend radius of elevator tension members, and conversely increasing tension member flexibility, is desirable. Among current tension member designs, composite belts having fiber or wire strands encased in a resin or polymer generally offer the greatest flexibility. An example of a known tension member is described in U.S. Pat. No. 9,126,805 to Pelto-Huikko et al., which is directed to an elevator rope including fiber reinforcements in a polymer matrix material. A coating material surrounds the polymer matrix material to increase friction and improve wear resistance of the tension member.
When a tension member is engaged with a sheave, the tension member is subjected to compression along an outer area in contact with the sheave and tension along an outer area away from the sheave. Frictional tractive force between the tension member and the pulley can impart additional compression to the outer surface of the tension member where the tension member is bent around the sheave. Many materials used to manufacture elevator tension members are significantly stronger in tension than compression. For example, carbon fiber, which is used in many composite belt designs such as in Pelto-Huikko et al., is typically only 20-70% as strong in compression as it is in tension. Therefore, tension members are typically more likely to fail as a result of internal compression experienced during the engagement with the sheave. Accordingly, the minimum bend radii of existing tension members is governed by internal compression loads due to bending.
Current tension members of polymer-encased fiber construction are typically produced using pultrusion processes. One such process is described in U.S. Pat. No. 3,960,629 to Goldworthy, which teaches a pultrusion method utilizing a thermosetting resin applied to conductive strands and cured via electrical induction. U.S. Pat. No. 8,343,410 to Herbeck et al. teaches a similar induction-based curing process for pultruded composite fiber articles. However, current pultrusion methods often have limited production speeds, and many current processes are suitable only for production of flat profiles. Moreover, many current pultrusion processes require the use of resin additives to prevent sticking of the resin to the various machine components used in the pultrusion process. Dilution of the resin with such additives compromises the mechanical properties of the cured thermoset, resulting in decreased breaking strength of the produced articles.
In view of the foregoing, there exists a need for composite elevator belts which reduce or neutralize compression loads such that the bending radius of the tension member is reduced while maintaining a high breaking strength. Additionally, there exists a need for methods and apparatuses for forming such composite elevator belts.
Embodiments of the present disclosure are directed to a pultrusion method for making a composite elevator belt, including pulling at least one load carrier strand coated with a core layer into a pultrusion die including a plurality of molding teeth and intervening spaces between the molding teeth having a profile shaped to form a desired profile of belt teeth on the core layer. The method further includes filling the intervening spaces between the molding teeth of the rotating die with resin, depositing the resin on the core layer, forming a plurality of the belt teeth on the core layer using the rotating die, pulling the core layer with formed belt teeth into a jacket extruder, and forming a jacket layer on the core layer with the formed belt teeth to complete the composite elevator belt.
In some embodiments, the method further includes, prior to pulling the core layer into the pultrusion die, pulling the at least one load carrier strand into a core impregnator and forming the core layer around the at least one load carrier strand.
In some embodiments, the method further includes heating the at least one load carrier strand in the core layer to cure the resin deposited onto the core layer by the rotating die.
In some embodiments, the method further includes supplying a coolant to a cooling chamber in the rotating die to regulate the temperature of the plurality of molding teeth as the rotating die rotates.
In some embodiments, the method further includes supplying a cleaning agent to the plurality of molding teeth as the rotating die rotates.
In some embodiments, the method further includes supplying an agent to the plurality of molding teeth as the rotating die rotates to prevent resin from sticking to the molding teeth as the resin is deposited onto the core layer.
In some embodiments, the resin is deposited on the core layer under pressure to remove bubbles from the core layer.
In some embodiments, the jacket layer is formed parallel to the core layer.
In some embodiments, the plurality of belt teeth is formed to extend transversely across a top surface of the core layer, the plurality of belt teeth including a root portion associated with the core layer and a tip portion. At least the tip portion is associated with a bottom surface of the jacket layer.
In some embodiments, the method further includes forming a second plurality of belt teeth on a second side of the core layer using a second rotating die opposing the first rotating die.
Further embodiments of the present disclosure are directed to a pultrusion die for forming a composite elevator belt. The pultrusion die includes a housing and a first rotating die enclosed in the housing and including a plurality of molding teeth and a plurality of intervening spaces between the molding teeth. The intervening spaces have a profile shaped to form a desired profile of a plurality of belt teeth on a core layer in the composite elevator belt. The pultrusion die further includes a first resin chamber enclosed in the housing and an injection opening in the housing to supply resin under pressure to the first resin chamber. The intervening spaces between adjacent molding teeth are in fluid communication with the first resin chamber to deposit the resin onto the core layer of the composite elevator belt to form the plurality of belt teeth using the first rotating die.
In some embodiments, the die further includes a central heating element associated with the housing and configured to cure the resin deposited on the core layer.
In some embodiments, the central heating element includes one or more inductive coils configure to heat an electrically conductive material in the composite elevator belt.
In some embodiments, the die further includes a cooling chamber in the housing and a coolant opening in the housing to supply coolant to the cooling chamber to cool the molding teeth of the rotating die.
In some embodiments, the die further includes a cleaning opening in the housing configured to provide a cleaning agent to the molding teeth of the rotating die.
In some embodiments, the die further includes a repellant opening in the housing configured to provide an agent to the molding teeth of the rotating die to prevent deposited resin from sticking to the molding teeth.
In some embodiments, the die further includes an entry heating element configured to heat the core layer entering the housing.
In some embodiments, the die further includes an exit heating element configured to heat the core layer and the plurality of belt teeth formed on the core layer.
In some embodiments, the die further includes a second rotating die enclosed in the housing opposing the first rotating die, the second rotating die including a second plurality of molding teeth and a second plurality intervening spaces between the second plurality of molding teeth. The second plurality of intervening spaces have a profile shaped to form a desired profile of a second plurality of belt teeth on a second side of the core layer in the composite elevator belt. The die further includes a second resin chamber enclosed in the housing and a second injection opening in the housing to supply resin under pressure to the second resin chamber. The second plurality of intervening spaces between adjacent teeth of the second plurality of molding teeth are in fluid communication with the second resin chamber to deposit the resin onto the second side of the core layer of the composite elevator belt to form the second plurality of belt teeth using the second rotating die.
In some embodiments, the first rotating die and the second rotating die are configured to rotate at different speeds.
Further embodiments of the present disclosure will now be described in the following numbered clauses:
Clause 1. A pultrusion method for making a composite elevator belt, comprising: pulling at least one load carrier strand coated with a core layer into a pultrusion die comprising a plurality of molding teeth and intervening spaces between the molding teeth having a profile shaped to form a desired profile of belt teeth on the core layer; filling the intervening spaces between the molding teeth of the rotating die with resin; depositing the resin on the core layer; forming a plurality of the belt teeth on the core layer using the rotating die; and pulling the core layer with formed belt teeth into a jacket extruder; forming a jacket layer on the core layer with the formed belt teeth to complete the composite elevator belt.
Clause 2. The pultrusion method of clause 1, further comprising: prior to pulling the core layer into the pultrusion die, pulling the at least one load carrier strand into a core impregnator; and forming the core layer around the at least one load carrier strand.
Clause 3. The pultrusion method of clause 1 or 2, further comprising heating the at least one load carrier strand in the core layer to cure the resin deposited onto the core layer by the rotating die.
Clause 4. The pultrusion method of any of clauses 1 to 3, further comprising supplying a coolant to a cooling chamber in the rotating die to regulate the temperature of the plurality of molding teeth as the rotating die rotates.
Clause 5. The pultrusion method of any of clauses 1 to 4, further comprising supplying a cleaning agent to the plurality of molding teeth as the rotating die rotates.
Clause 6. The pultrusion method of any of clauses 1 to 5, further comprising supplying an agent to the plurality of molding teeth as the rotating die rotates to prevent resin from sticking to the molding teeth as the resin is deposited onto the core layer.
Clause 7. The pultrusion method of any of clauses 1 to 6, wherein the resin is deposited on the core layer under pressure to remove bubbles from the core layer.
Clause 8. The pultrusion method of any of clauses 1 to 7, wherein the jacket layer is formed parallel to the core layer.
Clause 9. The pultrusion method of any of clauses 1 to 8, wherein the plurality of belt teeth is formed to extend transversely across a top surface of the core layer, the plurality of belt teeth comprising a root portion associated with the core layer and a tip portion; and wherein at least the tip portion is associated with a bottom surface of the jacket layer.
Clause 10. The pultrusion method of any of clauses 1 to 9, further comprising forming a second plurality of belt teeth on a second side of the core layer using a second rotating die opposing the first rotating die.
Clause 11. A pultrusion die for forming a composite elevator belt, comprising:
a housing; a first rotating die enclosed in the housing and comprising a plurality of molding teeth and a plurality of intervening spaces between the molding teeth, the intervening spaces having a profile shaped to form a desired profile of a plurality of belt teeth on a core layer in the composite elevator belt; a first resin chamber enclosed in the housing; and an injection opening in the housing to supply resin under pressure to the first resin chamber; wherein the intervening spaces between adjacent molding teeth are in fluid communication with the first resin chamber to deposit the resin onto the core layer of the composite elevator belt to form the plurality of belt teeth using the first rotating die.
Clause 12. The die of clause 11, further comprising a central heating element associated with the housing and configured to cure the resin deposited on the core layer.
Clause 13. The die of clause 11 or 12, wherein the central heating element comprises one or more inductive coils configure to heat an electrically conductive material in the composite elevator belt.
Clause 14. The die of any of clauses 11 to 13, further comprising: a cooling chamber in the housing; and a coolant opening in the housing to supply coolant to the cooling chamber to cool the molding teeth of the rotating die.
Clause 15. The die of any of clauses 11 to 14, further comprising a cleaning opening in the housing configured to provide a cleaning agent to the molding teeth of the rotating die.
Clause 16. The die of any of clauses 11 to 15, further comprising a repellant opening in the housing configured to provide an agent to the molding teeth of the rotating die to prevent deposited resin from sticking to the molding teeth.
Clause 17. The die of any of clauses 11 to 16, further comprising an entry heating element configured to heat the core layer entering the housing.
Clause 18. The die of any of clauses 11 to 17, further comprising an exit heating element configured to heat the core layer and the plurality of belt teeth formed on the core layer.
Clause 19. The die of any of clauses 11 to 18, further comprising: a second rotating die enclosed in the housing opposing the first rotating die, the second rotating die comprising a second plurality of molding teeth and a second plurality intervening spaces between the second plurality of molding teeth, the second plurality of intervening spaces having a profile shaped to form a desired profile of a second plurality of belt teeth on a second side of the core layer in the composite elevator belt; a second resin chamber enclosed in the housing; and a second injection opening in the housing to supply resin under pressure to the second resin chamber; wherein the second plurality of intervening spaces between adjacent teeth of the second plurality of molding teeth are in fluid communication with the second resin chamber to deposit the resin onto the second side of the core layer of the composite elevator belt to form the second plurality of belt teeth using the second rotating die.
Clause 20. The die of any of clauses 11 to 19, wherein the first rotating die and the second rotating die are configured to rotate at different speeds.
These and other features and characteristics of composite elevator belts, as well as the methods of operation and functions of the related elements of an elevator system, will become more apparent upon consideration of the following description and the appended claims with reference to the accompanying drawings, all of which form a part of this specification, wherein like reference numerals designate corresponding parts in the various figures. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only and are not intended as a definition of the limits of the disclosure. As used in the specification and claims, the singular forms of “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise.
For purposes of the description hereinafter, the terms “upper”, “lower”, “right”, “left”, “vertical”, “horizontal”, “top”, “bottom”, “lateral”, “longitudinal”, and derivatives thereof, shall relate to the disclosed apparatus as it is oriented in the figures. However, it is to be understood that the apparatus of the present disclosure may assume alternative variations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific systems and processes illustrated in the attached drawings and described in the following specification are simply exemplary examples of the apparatus disclosed herein. Hence, specific dimensions and other physical characteristics related to the examples disclosed herein are not to be considered as limiting.
As used herein, the terms “sheave” and “pulley” are used interchangeably to describe a wheel for tractive connection to a tension member of any type. It is to be understood that a “pulley” is encompassed by the recitation of a “sheave”, and vice versa, unless explicitly stated to the contrary.
As used herein, the term “supplementary”, when used to refer to a pair of angles, means a pair of angles whose sum is 180°. As used herein, the term “complementary”, when used to refer to a pair of angles, means a pair of angles whose sum is 90°.
As used herein, the term “substantially parallel to” means within plus or minus 5° of parallel unless explicitly indicated to the contrary. As used herein, the term “substantially perpendicular to” means within plus or minus 5° of perpendicular unless specifically indicated to the contrary.
As used herein, the terms “transverse”, “transverse to”, and “transversely to” a given direction mean not parallel to that given direction. Thus, the terms “transverse”, “transverse to”, and “transversely to” a given direction encompass directions perpendicular to, substantially perpendicular to, and otherwise not parallel to the given direction.
As used herein, the term “associated with”, when used in reference to multiple features or structures, means that the multiple features or structures are in contact with, touching, directly connected to, indirectly connected to, adhered to, or integrally formed with one another.
Referring to the drawings in which like reference numerals refer to like parts throughout the several views thereof, the present disclosure is generally directed to a composite elevator belt for use in an elevator system to raise and lower an elevator car. It is to be understood, however, that the composite belt described herein may be used in many different applications in which tension members are utilized in traction with sheaves. The present disclosure is also directed to an elevator system utilizing the composite elevator belt. Further, the present disclosure is directed to methods and apparatuses for making the composite elevator belt.
A first jacket layer 50 is provided and extends parallel to the core layer 20 in the longitudinal direction L. The first jacket layer 50 is spaced apart from the core layer 20 by the first plurality of teeth 30 and is associated with the tip portions 33 of each of the first plurality of teeth 30. Between each adjacent pair of the first plurality of teeth 30, a transverse groove is defined by the top surface 21 of the core layer 20, a bottom surface 52 of the first jacket layer 50, and the flanks 31 of the adjacent teeth 30. Similarly, a second jacket layer 60 is provided and extends parallel to the core layer 20 in the longitudinal direction L. The second jacket layer 60 is spaced apart from the core layer 20 by the second plurality of teeth 40 and is associated with the tip portions 43 of each of the second plurality of teeth 40. Between each adjacent pair of the second plurality of teeth 40, a transverse groove is defined by the bottom surface 22 of the core layer 20, a top surface 61 of the second jacket layer 60, and the flanks 41 of the adjacent teeth 40. These transverse grooves are void of core layer 20 and jacket layer 50, 60 material. A top surface 51 of the first jacket layer 50 and a bottom surface 62 of the second jacket layer 60 define contact surfaces of the composite elevator belt 100 and are configured for tractive, frictional engagement with a running surface of a sheave 200, as shown in
With continued reference to
Each of the first plurality of teeth 30 are spaced apart from adjacent teeth 30 by a pitch P1. Likewise, each of the second plurality of teeth 40 are spaced apart from adjacent teeth 40 by a pitch P2. The pitch P1 of the first plurality of teeth 30 may be the same or different than the pitch P2 of the second plurality of teeth 40, and the pitches P1, P2 may vary along the length of the composite elevator belt 100. Similarly, a height H1 of the first plurality of teeth may be the same or different than a height H2 of the second plurality of teeth 40.
Each of the teeth 30, 40 may have a generally polygonal profile, such as a trapezoidal profile, when viewed in a cross section perpendicular to the longitudinal direction L, such that the root portions 32, 42 are wider than the tip portions 33, 43, or vice versa. As shown in the embodiment of
Referring back to
In some embodiments, the profiles and arrangement of the first and second pluralities of teeth 30, 40 may be different at certain sections of the composite elevator belt 100 to account for differing load conditions experienced along the length of the composite elevator belt 100. As will be explained in greater detail below, the profile and arrangement of the teeth 30, 40 affects the compressive and tensile loads experienced by the core layer 20 and the strands 10 of the composite elevator belt 100. It may therefore be advantageous to shape and space the teeth 30, 40 in anticipation of the compressive and tensile loads expected in specific sections of the composite elevator belt 100. For example, some sections of the composite elevator belt 100 may only engage the sheave 200 during a small fraction of the total load cycles of composite elevator belt 100. These sections of the composite elevator belt 100 therefore experience less flexing cycles from sheave engagement than other sections of the composite elevator belt 100 which engage the sheave 200 during a larger fraction of the total load cycles. Accordingly, different tooth profiles and spacing may be utilized to optimize the life of the composite elevator belt 100 and to equalize wear and fatigue across various sections of the composite elevator belt 100 based on the differing load conditions experienced by the various sections of the composite elevator belt 100.
In still other embodiments, the profile and/or arrangement of the first plurality of teeth 30 may be different than the profile and/or arrangement of the second plurality of teeth 40 along the entire length of the composite elevator belt 100 or at certain sections of the composite elevator belt 100 to account for different loading conditions on opposite surfaces of the composite elevator belt 100. For example, at certain sections of the composite elevator belt 100, the first jacket layer 50 may engage the sheave 200 but the second jacket layer 60 may not. In these sections of the composite elevator belt 100, the first plurality of teeth 30 associated with the first jacket layer 50 may have a profile and/or arrangement advantageous for compressive loading due to sheave engagement, while the second plurality of teeth 40 associated with the second jacket layer 60 may have a different profile and/or arrangement advantageous for tensile loading. Conversely, at other sections of the composite elevator belt 100, the second jacket layer 60 may engage another sheave 200 but the first jacket layer 50 may not. In these sections of the composite elevator belt 100, the second plurality of teeth 40 associated with the second jacket layer 60 may have a profile and/or arrangement advantageous for compressive loading due to sheave engagement, while the first plurality of teeth 30 associated with the first jacket layer 50 may have a different profile and/or arrangement advantageous for tensile loading.
Still other embodiments of composite elevator belts 100 according to the present disclosure will be described later with reference to
Moreover, deformation of the composite elevator belt 100 around the sheave 200 causes each of the second plurality of teeth 40 to exert a normal force FN against the core layer 20. As explained above with reference to
The foregoing descriptions of
As shown in
Referring now to
Having described the structure and function of the composite elevator belt 100, one skilled in the art will appreciate that a variety of materials may lend themselves to use for the various components thereof. Examples of suitable materials will be generally described below and are further discussed in U.S. patent application Ser. No. 13/092,391, published as U.S. Patent Application Publication No. 2011/0259677, the entirety of which is incorporated by reference herein. Materials may be selected for their advantageous mechanical properties as well as for their compatibility with manufacturing methods suitable for making the composite elevator belt 100. Examples of such manufacturing methods will be subsequently be described with reference to
The at least one fiber or strand 10 may be made from a variety of natural and synthetic materials which are flexible yet exhibit a high breaking strength. Suitable materials for the at least one fiber or strand 10 thus include glass fiber, aramid fiber, carbon fiber, nylon fiber, metallic cable, and/or combinations thereof. As will be described below, some methods of manufacturing the composite elevator belt 100 utilize inductive heating of the strands 10. In such embodiments, it is advantageous that the material of the fiber or strand 10 is electrically conductive. In some embodiments, each of the strands 10 may be continuous along the longitudinal direction L over the entire length of the composite elevator belt 100. In other embodiments, the strands 10 may be interrupted along the longitudinal direction L, and may or may not overlap one another. In still other embodiments, the strands 10 may be entangled or stranded with one another along the length of the composite elevator belt 100. In some embodiments, the strands 10 may be arranged in multiple layers in a direction perpendicular to the longitudinal direction L.
The core layer 20 may be made of a polymer matrix material, such as a curable resin, suitable for deposition on the strands 10 and flexible when cured. The material of the core layer 20 may be selected based on its curing properties such as the curing rate and the responsiveness of the curing rate to heat. As such, the speed of the curing process of the core layer 20 and the overall production rate of the composite elevator belt 100 may be increased by various heating devices as will be described below. Some methods of manufacturing the composite elevator belt 100 utilize inductive heating of the core layer 20. In such embodiments, it is advantageous that the material of the core layer 20 is inherently electrically conductive or is mixed with an electrically conductive additive.
The first and second jacket layers 50, 60 may be made of a polymer material selected for flexibility and to promote friction with the sheave 200. Additionally, the material of the first and second jacket layers 50, 60 may be selected for wear resistance of the first and second jacket layers 50, 60 and/or to prevent galling and other damage to the sheave 200. Suitable materials for the first and second jacket layers 50, 60 thus include curable resins such as urethanes, in particular thermoplastic polyurethane (TPU). The material of the first and second jacket layers 50, 60 may be softer than the material of the core layer 20 by, for example, a factor of ten.
The first and second pluralities of teeth 30, 40 may be made of a polymer material having sufficient stiffness and rigidity to deform the core layer 20 as described above with reference to
Embodiments of the composite elevator belt 100 described herein are particularly suited for manufacturing via a pultrusion process.
The roving spool rack 2100 includes one or more spools 2110 on which the strands 10 are wound. Each strand 10 of the composite elevator belt 100 may be associated with one of the spools 2110. The one or more spools 2110 may be free-spinning such that a tension force applied to free ends of the strands 10 causes the strands 10 to be unwound from the one or more spools 2110. In some embodiments, the one or more spools 2110 may be motorized to assist in the unwinding of the strands 10.
The core impregnator 2200 is configured to pre-form the core layer 20 onto the strands 10. The core impregnator 2200 includes an injector 2210 configured to supply the material that will form the core layer 20 to a bath chamber 2220 in a liquid phase. The bath chamber 2220 has openings at both ends along the pulling direction DP to allow the strands 10 to be pulled through the bath chamber 2200, coating the strands 10 in the core layer 20 material.
The pultrusion die 2300 is configured to finalize the encasing of the strands 10 with the core layer 20 and to apply the first and second pluralities of teeth 30, 40 to the core layer 20. The pultrusion die 2300 includes a housing 2310 enclosing one or more rotating dies 2320, 2321 (see
Referring now to
The rotating dies 2320, 2321 of the pultrusion die 2300 may have hollow cross centers which serve as cooling chambers 2323. Fluid coolant may be circulated through the cooling chambers 2323 via coolant openings 2324 in the housing 2310 to regulate the temperature of the rotating dies 2320, 2321. Additionally, the housing 2310 may include one or more cleaning openings 2370 for providing cleaning agents to the rotating dies 2320, 2321. Moreover, the housing 2310 may include repellant openings 2380 for providing lubricants and other agents to prevent sticking and accumulation of the material in the resin chambers 2330, 2331 on the rotating dies 2320, 2321. The pultrusion die 2300 and the associated production process allows for be better control of belt quality via observation of the molding teeth 2322 of the rotating dies 2320, 2321 as the molding teeth 2322 apply resin to and disengage from the core layer 20. If it is observed that resin begins sticking to the molding teeth 2322, the rotational speed of the rotating dies 2320, 2321 and the tractor 2500 may be adjusted; agents may be supplied to the molding teeth 2322 via the cleaning opening 2370 and/or repellant openings 2380; and/or the temperature of the rotating dies 2320, 2321, core layer 20, or resin chambers 2330, 2331 may be adjusted to improve the production quality.
In some embodiments, the central heating element 2340 may include one or more induction coils 2341 configured to generate eddy currents in the strands 10, which may be electrically conductive, according to well-known principles of induction heating. Heating of the strands 10 causes the partially-formed composite elevator belt 100 to be heated from the inside out, thereby reducing the occurrence of air bubbles as the core layer 20 and/or the teeth 30, 40 cure. As noted above, in some embodiments, the core layer 20 material and/or teeth 30, 40 material may include conductive additives also capable of being heated by the induction coils 2341. Other embodiments of the central heating element 2340 may utilize heating devices other than induction coils. Similarly, the entry heating element 2350 and/or exit heating element 2360 may include induction coils or other heating devices.
The central heating element 2340, entry heating element 2350, exit heating element 2360, and cooling chambers 2323 are configured to work in conjunction to finely control the temperature of the partially-formed composite elevator belt 100 throughout the formation of the core layer 20 and the teeth 30, 40. As such, the pultrusion die 2300 permits a wider variety of materials to be used in production of the composite elevator belt 100 than is possible utilizing conventional pultrusion processes. In some embodiments, the core layer 20 and the teeth 30, 40 may be formed of fast curing materials, allowing the overall production speed of the composite elevator belt 100 to be increased relative to conventional pultrusion processes.
Referring back to
The tractor 2500 applies a pulling force to pull the composite elevator belt 100 through the preceding components of the manufacturing apparatus 2000. The pulling force of the tractor 2500 is imparted to the composite elevator belt 100 by one or more driven rollers 2510 configured to frictionally engage the finished composite elevator belt 100 exiting the jacket extruder 2400. The driven rollers 2510 may be rotated by a motor to govern the speed of the manufacturing process.
The spooler 2600 is configured to wind the finished composite elevator belt 100 into a spool for packaging. The spooler includes a driven axle 2610 configured to wind the composite elevator belt 100 into a spool at the same rate at which the tractor 2500 pulls the composite elevator belt 100.
Having described the individual components of the manufacturing apparatus 2000, further reference is now made to
At step 3200, the strands 10 are pulled by the tractor 2500 into the bath chamber 2220 of the core impregnator 2200, where the strands 10 are coated with the material forming the core layer 20. More particularly, the bath chamber 2220 is supplied with liquid phase core layer 20 material via the injector 2210. The material in the bath chamber 2200 may or may not be pressurized. As the strands 10 pass through the material in the bath chamber 2200, some or all of the material adheres to the strands 10 to at least partially form the core layer 20 of the composite elevator belt 100.
At step 3300, the partially-formed composite elevator belt 100 is pulled by the tractor 2500 into the pultrusion die 2300. The incoming strands 10 are heated by the entry heating element 2350 to a predetermined temperature for optimally controlling the cure of the materials used for the core layer 20 and the first and second pluralities of teeth 30, 40. In the housing 2310, the rotating rotating dies 2320, 2321 apply pressure to the core layer 20 material applied in the core impregnator 2200 to finalize the profile of the core layer 20. In addition, the pressure applied to rotating dies 2320, 2321 forces bubbles and any other discontinuities and imperfections out of the core layer 20. Concurrently with forming the core layer 20, the rotating dies 2320, 2321 draw material from the resin chambers 2330, 2331 and apply it to the core layer 20 to form the first and second pluralities of teeth 30, 40 integrally with the core layer 20. The rotational speed of the rotating dies 2320, 2321 may be calibrated to define the spacing at which the first and second pluralities of teeth 30, 40 are deposited on the core layer 20. Specifically, increasing the rotational speed of the rotating dies 2320, 2321 decreases the spacing between the teeth 30, 40, and decreasing the rotational speed of the rotating dies 2320, 2321 increases the spacing between the teeth 30, 40.
In some embodiments, the rotational speed of the rotating dies 2320, 2321 may be adjusted during production of the composite elevator belt 100 to change the tooth spacing at different sections of the composite elevator belt 100. In some embodiments, the rotating dies 2320, 2321 may be rotated at different speeds relative to one another such the first plurality of teeth 30 have different spacing than the second plurality of teeth 40. In some embodiments, he rotating dies 2320, 2321 may be synchronized to define an offset of the teeth 30, 40 on both sides of the load carrier. In one embodiment, the rotational speed of the rotating dies 2320, 2321 is synchronized with the linear speed of the core layer 20 being pulled through the pultrusion die 2300. That is, the linear speed of the core layer 20 may be equal to circumferential speed at which each of the molding teeth 2322 rotate, such that with each 360° rotation of the rotating dies 2320, 2321, a length of the core layer 20 equal to the circumference of the rotating dies 2320, 2321 passes through the pultrusion die 2300. The rotating dies 2320, 2321 may be motorized to assist the tractor 2500 and to enhance the quality of the outer load carrier shape.
The central heating element 2340 and the cooling chambers 2323 regulate the temperature of the strands 10, the core layer 20, and the material forming the teeth 30, 40 to optimally control curing of the core layer 20 and the teeth 30, 40. As some of the molding teeth 2322 of the rotating dies 2320, 2321 are applying the teeth 30, 40 to the core layer 20, others of the molding teeth 2322 are treated with agents from the cleaning openings 2370 and the repellant openings 2380 before being reintroduced to the resin chambers 2330, 2331. The outgoing partially-formed composite elevator belt 100 is heated by the exit heating element 2360 to a predetermined temperature for optimally controlling the cure of the materials used for the core layer 20 and the first and second pluralities of teeth 30, 40. At this stage, the core layer 20 and/or the teeth 30, 40 may or may not be fully cured.
At step 3400, the partially-formed composite elevator belt 100 is pulled by the tractor 2500 into the jacket extruder 2400. The first jacket layer 50 and second jacket layer 60 are applied to the tip portions 33, 43 of the first and second pluralities of teeth 30, 40. The at least one extruder head 2410 of the jacket extruder 2400 may be calibrated such that the material of the first and second jacket layers 50, 60 is deposited onto the teeth 30, 40 in liquid phase, with or without filling the transverse grooves between the flanks 31, 41 of adjacent teeth 30, 40. The first and second jacket layers 50, 60 are then cured so as to be integral with the teeth 30, 40. Additionally, the core layer 20 and the teeth 30, 40, if not fully cured already, finish their respective curing processes.
At step 3500, the finished composite elevator belt 100 is wound onto the spooler 2600 via the driven axle 2610. The driven axle 2610 may be calibrated to wind the composite elevator belt 100 onto the spooler 2600 at the same rate at which the composite elevator belt 100 is pulled by the tractor 2500 in order to prevent the occurrence of slack in the composite elevator belt 100. The composite elevator belt 100 is wound onto the spooler 2600 until the desired length of the composite elevator belt 100 has been attained. At that point, the spool of the composite elevator belt 100 may be removed from the spooler 2600. As may be appreciated by those skilled in the art, the composite elevator belt 100 may be produced to a theoretically infinite length limited only by the supply of the raw materials for the strands 10, core layer 20, teeth 30, 40, and jacket layers 50, 60.
Steps 3100-3500 may be performed concurrently with one another as the composite elevator belt 100 is continuously drawn through the manufacturing apparatus 2000. That is, as the first and second jacket layers 50, 60 are applied to a first portion of the partially-formed composite elevator belt 100 by the jacket extruder 2400, the teeth 30, 40 are applied to a second portion of the partially-formed composite elevator belt 100 by the pultrusion die 2300, and the core layer 20 is applied to a third portion of the partially-formed composite elevator belt 100 by the core impregnator 2200. It should be understood that the first, second, and third portions of the partially-formed composite elevator belt 100 referred to above are not discrete, but rather are continuously changing as the partially-formed composite elevator belt 100 is drawn through the manufacturing apparatus 2000.
In other embodiments of the method for making the composite elevator belt 100, one or more of steps 3100-3500 may be performed as discrete operations rather than as a continuous process. For example, steps 3100-3300 may be performed to unwind the strands 10 from the roving spool rack 2100, apply the core layer 20 material to the strands, finalize profile of the core layer 20 and form the teeth 30, 40 on the core layer 20. The load carrier may then be wound onto a temporary storage spool, and steps 3400-3500 may be performed separately. It is to be understood that this embodiment is merely exemplary, and those skilled in the art will appreciate that any individual step or combination of steps 3100-3500 may be performed as a discrete process distinct from the remaining steps 3100-3500.
The manufacturing apparatus 2000 described with reference to
Referring now to
The embodiment of
The embodiment shown in
It is to be further understood that the embodiments of the composite elevator belt 100 shown in
The embodiments of the composite elevator belt 100 shown in
While several examples of a composite elevator belt for an elevator system, as well as methods and apparatuses for making the same, are shown in the accompanying figures and described in detail hereinabove, other examples will be apparent to, and readily made by, those skilled in the art without departing from the scope and spirit of the present disclosure. For example, it is to be understood that aspects of the various embodiments described hereinabove may be combined with aspects of other embodiments while still falling within the scope of the present disclosure. Accordingly, the foregoing description is intended to be illustrative rather than restrictive. The assembly of the present disclosure described hereinabove is defined by the appended claims, and all changes to the disclosed assembly that fall within the meaning and range of equivalency of the claims are to be embraced within their scope.