MXPA06009989A - Mixing drum - Google Patents

Abstract

A rotary concrete mixing drum (16) includes an interior surface (74) at least partially provided by a polymer (90) impregnated with a slip agent.

Description

DRUM FOR MIXING The present application claims priority under the ü.S.C. 35 §119 (e) of the Provisional Patent Application Ü.S. co-pending Series no. 60 / 550,190 filed March 4, 2004 for Illiam D. Tippins, Anthony J. Khouri and William Rodgers, and entitled DRUM FOR MIXING, which is incorporated herein in its entirety for reference.

BACKGROUND The front discharge of the drums for concrete mixing, in general, extends over a vehicle cab and unloads concrete to the front of the vehicle. Because these drums must extend above and above the booth, the front discharge drums are extremely long, usually requiring extra sections that must be secured together, this extra length subjects the drum parts to greater fatigue and creates additional seams where The concrete can be collected as a result, cleaning the front discharge drum is even more annoying and needs time compared to cleaning the interior of the rear discharge drums.In addition to accumulating inside the concrete mixer drum, the concrete It also frequently accumulates on the outside of the drum.The accumulation of concrete on the outside of the drum also increases the time and cost of cleaning the drum.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a side elevation view of a concrete mixer vehicle having a mixer drum according to an exemplary embodiment. Figure 2 is a sectional view of the drum of Figure 1. Figure 3 is a fragmentary, enlarged sectional view of a part of the drum of Figure 1. Figure 4 is a fragmentary, enlarged sectional view of a barrel of the drum of Figure 1. Figure 5 is a side elevation view of an alternative embodiment of the concrete mixing vehicle of Figure 1 with another embodiment of the mixing drum. Figure 6 is a perspective view of the mixing drum of Figure 5. Figure 7 is a sectional view of the drum of Figure 5 taken along line 7-7. Figure 8 is a sectional, partial view of the drum of Figure 5.

DESCRIPTION Figure 1 is a side elevational view of a concrete mixer truck 10 which generally includes chassis 12, booth 14, drum 16, drum mixer and drum drive 17, and delivery system 18. Chassis 12 generally supports and energizes the remaining components of the truck 10 and generally includes the frame 20, the power source 22, the drive train 24 and the wheels 26. The frame 20 provides the mixer truck 10 with the structural support and rigidity necessary to transport large loads of concrete. The power source 22 is coupled to the frame 20 and generally comprises a rotating mechanical power source that is derived from a stored energy source. Examples include, but are not limited to, a gas-fired internal combustion engine, a diesel engine, turbines, fuel cell-driven engines, electric motor or any other type of motor capable of providing mechanical power.

For the purposes of this description, the term "coupled" means the union of two members directly or indirectly to one another. This connection may be fixed or mobile in nature. These connections can be achieved with the two members or the two members and any additional intermediate member formed integrally as a unitary individual body with each other or with the two members or the two members and any additional intermediate members joined together. These unions can be permanent in nature or alternatively can be removed or separated.

The drive train 24 engages between the power source 22 and the wheels 26 and transfers energy (or movement) from the power source 22 to the wheels 26 to drive the truck 10 in a forward or backward direction. The drive train 24 includes a transmission 25 and a reduction unit at the end of the wheel 27. The transmission and the reduction unit at the end of the wheel 27 use a series or set of gears to adjust the transmitted torque by the power source 22 to the wheels 26. An example of a reduction unit at the end of the wheel is described in Patent Application U.S. Copendiente Series No. 09/635, 579, filed August 9, 2000, by Brian K. Anderson entitled "NON-CONTACT SPRING GUIDE," the entire description is incorporated herein by reference.

The cab 14 is coupled to the chassis 12 and includes a closed area from which a truck operator 10 operates and controls at least some of the functions of the truck 10.

The control unit or control train 18 is operatively coupled to the energy source 22 and the mixing drum 16 and uses the energy or movement of the energy source 22 to provide a rotating force or torsion to the mixing drum 16. According to an alternative mode, the drive train can be energized by another source different from the power source 22 that is provided in the truck 10.

The mixing drum 16 contains concrete or other material mixed by the truck 10. The mixing drum 16 includes a barrel 30, projections 32 (shown in Figure 2), drive ring 34, roller ring 36 and a removable cover assembly (not shown). The barrel 20 is an elongated vessel having an opening 38 in a first axial end portion 40 and driving ring 34 coupled to an opposite axial end portion 42. The barrel includes a main part in the form of but or drop 44 and a nozzle part in the form of a conical frusto funnel 46.

The main part 44 provides the majority of the internal volume of the barrel 30 and in general has a convex outer surface 48. The nozzle part 46 generally has a linear surface of decreasing section 50. The surfaces 48 and 50 are fused together to a part intermediate concave 54. As shown in Figure 1, the nozzle part 46 extends from the main part 44 above and above the car 14 generally ends in an opening 38. The opening 38 communicates with the interior of the drum 16, the which have an interior surface fully provided by an interior surface 58 of the barrel 30 and an exterior surface of projections 32 (shown in Figures 2 and 3). As will be described in more detail below, the inner surface 56 of the drum 16, and more particularly, the inner surface 58 of the barrel 30 and the outer surface 60 of the projections 32 are configured to inhibit the adhesion of concrete and other aggregates to these surfaces. . The upper outer 48 and 50 of the barrel 30 are also configured to provide a smooth surface that inhibits the collection of the concrete and other aggregates.

The projection 32 (shown in Figure 2) spirals into the interior of the barrel 30 and protrudes from the interior surface 58 of the barrel 30. The projections 32 (also known as fins, propellers, veins, screws or formations) are specifically configured to move the concrete and aggregates within the barrel 30 to the opening 38 when the drum 16 rotates in the first direction. In contrast, the projections 32 are configured to move the concrete and aggregate toward the terminal portion 42 to mix the concrete when the drum 16 rotates in a second opposite direction.

The drag ring 34 (also known as gear wheel, spider, daisy, etc.) is located on the terminal part 42 of the barrel 30 and is configured to operate coupled to the drum 16 to drive the drum 17. The roller ring 36, a circular annular member that fits around the outside of the barrel 30 of the drum 16 at a location, generally, between the terminals 40 and 42. The roller ring 36 is configured to serve as a surface on which the rollers 64 engage the frame 20 runs as drum 16 rotates. Examples of potential constructions for trailing ring 34 and roller ring 36 are found in co-pending International Patent Application Series No. PCT / US03 / 25656 entitled Mixing Drums and filed on August 15, 2003 by Anthony Khouri, William Rogers and Peter Saad, the full description of this patent is incorporated herein by reference.

The handle of the drum 17 (also known as the control unit) is operatively coupled to the energy source 22 and the mixing drum 16. The drum control 17 transmits energy or movement from the energy source 22 to provide a rotary force or motor torque to the rotary drum 16. An example of a drum control mode 17 is described in US Pat. 5,820,258 entitled Cement Mixer Drum Support, filed on October 13, 1998, is incorporated in its entirety for reference.

The delivery system 18 generally comprises one or more structures positioned adjacent the terminal portion 40 of the drum 16, which is configured to receive the concrete and aggregates through the opening 38 and deliver the concrete or aggregate to the designated location. . Delivery system 18 includes discharge tube 66 and slide 68. Discharge tube 66 channels the concrete in slide 68, which guides the flow of concrete or other aggregate into a channel to the desired location.

Figures 2 to 4 show the barrel 30 and the projections 32 in greater detail. Figure 2 is a sectional view of the drum 16. Figure 3 is a fragmentary, elongated sectional view of the drum 30 and the projections 32.

Figure 4 is a fragmentary, elongated sectional view of the drum of Figure 3 taken along line 4-4. In the particular example shown in Figures 2 to 4, the drum 16 is formed substantially from two main layers 74, 76 of material extending transverse to an axial center point of the drum 16 and extending particularly from the terminals 40 to 42. Layers 74 and 76, in general, serve to provide the main structure of the drum 16. Although not shown, additional non-structural layers or additional coatings may be added. For example, relatively thin paint, decals, coatings or other nonstructural layers can be applied to the exterior of the layer 76. For the purposes of this description, the use of the term "exterior" with reference to barrel 30 or drum 16, in general it refers to the exterior of the layer 76 despite the potential presence of additional non-structural layers on top of the layer 76, such as decals, paint, coatings or other nonstructural layers. Because the layers 74 and 76 extend transverse to an axial midpoint of the drum 16 and extend from the terminal portion 40 to the end portion 42, the drum 16 has improved its structural strength along the axial length between the main part 44 and nozzle part 46. Furthermore, because the layers 74 and 76 extend continuously and integrally as unitary bodies from the terminal part 40 to the terminal part 42, the drum 16 lacks seams or joints where, on the other hand way, the sections would be secured or held together. As a result, drum 16 lacks interior corners where concrete or aggregate can be collected, making cleaning easier. At the same time, the exterior of the drum 16 also lacks discontinuous surfaces, protruding flanges (other than roller rings 36) or other abrupt surface contours where concrete and aggregate can be collected, further simplifying the cleaning of the drum 16 Layer 74, in general, comprises a polymer impregnated or cast with a slip agent. For the purposes of this description, the term "slip agent" refers to any substance, solid or liquid, that when mixed with a polymer reduces the coefficient of friction of the polymer along the surface and compared to the same polymer without the substance. In a particular embodiment, the slip agent has a surface energy less than the surface tension of a low-slump concrete of Portland Cement. In another embodiment, the slip agent has a surface energy of less than about 20 dynes per centimeter. In one embodiment, the slip agent is configured not to migrate considerably within the polymer. As a result, the slip agent does not migrate to a boundary between layers 76 and 76, which present lamination. In one embodiment, the slip agent is a polydecene. In another embodiment, the slip agent is a poly-alpha olefin. In another embodiment, the slip agent is a polytetrafluoroethylene. In another embodiment, other slip agents may be employed.

In one embodiment, the polymer in which the slip agent was impregnated includes polyurethane. According to the example mode, the slip agent impregnated in the polyurethane is polytetrafluoroethylene. The polytetrafluoroethylene comprises a powder. Because polytetrafouroethylene is a solid, it is firmly held in place by the polyurethane matrix. The polytetrafluoroethylene is at least 2% by weight of the impregnated polyurethane. In particular, it has been found that impregnation of the polyurethane with at least 2% by weight of the polytetrafluoroethylene reduces the adhesion of the concrete and other material added to the inner surfaces 56 of the drum 16. In the exemplary embodiment, polytetrafluoroethylene has a percentage of weight of less than 5% of the impregnated polyurethane. As a result, the impregnated polytetrafluoroethylene does not impact or significantly weaken the polyurethane. In particular embodiments where the physical strength of the impregnated polymer is not required, the polytetrafluoroethylene may have a higher percentage by weight of the impregnated polyurethane.

According to an exemplary embodiment, the polytetrafluoroethylene comprises a Teflon powder sold under the trademark Zonyl MP'1600 by Dupont. Zonyl MP-1600N is a fluoroadditive in the powder form, which can be used at temperatures from 190 to 250 ° C. Zonyl MP-1600N is inert to almost all industrial chemicals and solvents. It is a good electrical insulator, does not absorb water and is highly weather resistant. "Zonyl MP-1600 has a peak melt temperature of approximately 325 ° C (ASTMD 4894), has a particle size distribution (volume basis) average of 12 micrometers (measured by Microtack Laser), and has a specific surface area of 812M2 / G (tested by means of nitrogen absorption) (complies with ASTMD D5675, Type I, Grade 3, Class A). In other embodiments, other polytetrafluoroethylenes with other particle sizes or in other forms may be employed.

According to one embodiment, the polytetrafluoroethylene powder is dispersed in a polyol using high mixing by cutting with a Cowles propeller. In one embodiment, the polytetrafluoroethylene powder is mixed with the polyol before being added to a prepolymer and a plasticizer, Benzoflex. This process results in the polytetrafluoroethylene powder being distributed or finely incorporated through the polymer matrix (polyurethane). Because the polytetrafluoroethylene powder is mixed with the polyol before adding it to the prepolymer or Benzoflex, the mixture has a low surface tension, which reduces the amount of air on the surface of the polytetrafluoroethylene powder and reduces the air bubbles formed by air coalescence during the reaction of the polyol / prepolymer. By reducing the number of air bubbles in the impregnated polymer, the strength of the impregnated polymer (impregnated polyurethane) is increased.

According to another embodiment, the slip agent comprises a poly-alpha-olefin sold under the trademark SYNTON oil by Crompton Corporation. SYNTON oil is a polydecene. In particular, SYNTON oil is SYNTON PAO 100.

SYNTON PAO 100 has a kinematic viscosity at 100 ° C of 100, a specific gravity (20/20 ° C) of 0.847, a flash point, degrees Celsius, ASTMD-92 DE 301, a flame point in degrees Celsius, ADTMD-92 D of 327 and a poor point, degrees Celsius , ASTMD-97 of -24.

In embodiments in which the polyalphaolefin fluid is impregnated in the polyurethane and has a weight percentage of between 2 and 5 percent, the coefficient of friction of inner surfaces 56 is reduced by about 55%. Due to its highly branched structure, the migration of the polyalphaolefin fluid within the polyurethane matrix is relatively slow. As a result, the fluid does not migrate to the layer 76. In a particular embodiment, the polyalphaolefin fluid has a weight percentage of at least 1% of the impregnated polymer (polyurethane). As a result, the adhesion of the concrete to the surface 56 is light. In another embodiment, the polyalphaolefin fluid has a weight percentage of at least 2% of the impregnated polymer, resulting in the impregnated polymer having imperceptible adhesion of the concrete to the surface 56. In one embodiment, the polyalphaolefin fluid has a percentage by weight no greater than 5% of the impregnated polymer. As a result, the physical properties of the polyurethane are not affected. In particular applications, the polyalpha olefin fluid -i has a higher percentage by weight of the impregnated polymer wherein the physical properties of the required polymer are not stringent. The polyalphaolefin fluid significantly reduces the coefficient of friction of the polyurethane at levels at which it does not significantly degrade the physical strength or structural qualities of the polyurethane. In addition, the polyalphaolefin fluid does not transport air during its impregnation or addition to the polymer. The following table indicates the physical qualities of the impregnated polyurethane (provided by ERA polymers) when impregnated with 1%, 2% and 5% by weight of polytetrafluoroethylene powder (Zonyl MP ~ 1600n) and the impregnated polyurethane when impregnated with a polyalphaolefin fluid ( SYNTON oil PAO 100) at levels of 1%, 2% and% by weight.

Above all, because the layer 74 is formed of an I polymer impregnated with a slip agent, the layer 14 that forms the inner surfaces 56 of the drum 16 has a lower coefficient of friction and adheres less to the concrete or other aggregate when mixed. inside the drum 16. During the mixing of the concrete and aggregate, the surfaces 56 are normally scoured, forming small grooves and cracks, in which the concrete forms a mechanical bolt and hardens. However, due to its low coefficient of friction, surface 56 prevents the collection of concrete or other aggregate within these cracks. Moreover, because the slip agent is impregnated or at least partially distributed through the polymer to form the layer 74, the layer 74 is durable enough not to wear out in an excessive proportion compared to a layer consisting only of one slip agent such as polytetrafluoroethylene. In addition, the structural strength of other physical qualities of the polymer is preserved and used in particular embodiments. Although particular examples have been provided describing the use of polytetrafluoroethylene or a polyalphaolefin fluid impregnated with a polymer such as polyurethane, other polymers and other slip agents may alternatively be used in various relative concentrations depending on the physical qualities required of the impregnated polymer. Although layer 74 is described as a polymer impregnated with a slip agent to reduce the coefficient of friction and adhesion of the resulting material, layer 74 can alternatively be formed by a slip agent, such as a polytetrafluoroethylene, impregnated with a strength or durability agent. , characterized in that the strength or durability agent is a substance in which, upon addition to the slip agent, the strength or durability of the slip agent increases.

In the particular embodiment shown, the layer 74 extends along the interior surface 58 or barrel 30 as well as on the exterior surfaces 60 of the projections 32. As shown in Figure 3, in a particular embodiment, the layer 74 forms all of the thickness of the projection 32 in a radial middle portion of the projection 32. As shown in Figure 2, the layer 74, which provides the inner surface 56 of the drum 16, is provided by means of two sections elongated, half-arched or helical 80, 82. Each section 80, 82 provides an inner surface 58 of the barrel 30 and provides a projection 32. The sections 80 and 82 are spirally wound or screwed together with their edges extending adjacent or very next to each other.

After the sections 80 and 82 are positioned adjacent to each other, each of the sections 80 and 82 extend considerably from the terminal portion 40 to the terminal portion 42, the layer 76 is formed in an integrated, continuous manner from the terminal 40 to terminal part 42 on sections 80 and 82 and transverse to the seams between sections 80 and 82. In a particular embodiment, layer 76 is formed of glass fiber windings, which are coated with resin and wrapped or windings on and around layer 74 and sections 80 and 82. In one embodiment, the resin is Hetron 942, available from Ashland Chemical, in Dublin, Ohio, and the fibers are glass fibers, preferably 2400 Tex E glass ( approximately 206 yards per pound). The angles at which the fibers are wound around the layer 74 on a major axis (where the barrel 30 has a larger diameter) is about 10.5 degrees relative to the central axis of the barrel 30. During the winding process, the fiber spirals that cover the resin are wrapped, in general, from one terminal part of the drum to the other. The ribbon of the spirals is wrapped around the drum so there is approximately 50% overlap between each step of the ribbon. The wrapping of the fibers or spirals from the terminal part to the terminal part provides the drum 16 with the structural support to resist various forces in various directions. More detailed information on sections 80, 82, projections 32 and 1 layer fiberglass coils 76 are provided in copending International Patent Application Series No. PCT / US03 / 25656 entitled Mixing Drum, which is hereby incorporated in its entirety for reference and reference. International Patent Application Copendent Series No. PCT / AU03 / 00664 filed on May 31, 2003 by Anthony Khouri entitled "Drum" Concrete Mixer Mounted on a Vehicle and Manufacturing Methods thereof, characterized in that the International Patent Application Series No. PCT / AU03 / 00664 is incorporated in its entirety for reference .. Layer 74 of the present application is similar to the inner polymer layer forming the inner surface of the drum and protrusions described in copending International Patent Application Series No. PCT / US03 / 25656 and the copending International Patent Application Series No. PCT / AU03 / 00664 except that the layer 74 is impregnated with a slip agent.

Figure 4 is a fragmentary, highly elongated sectional view of the layers 74 and 76 along the barrel 30.

Figure 4 shows a process for finishing exterior surfaces 48 and 50 of barrel 30 for outer surface of drum 16 to be smoother, facilitating the improved application of paint, labels, decals or other aesthetic layers on layer 76 and further facilitating the Improved cleaning of the exterior of the drum 16 by reducing the adhesion on the outside of the drum 16. As shown in Figure 4, the layer 74 includes the impregnated polymer layer 90 comprising a polymer impregnated with a slip agent (as described above). ) and a layer 92 of glass reinforced plastic, which is bonded to layer 90 during the molding of sections 80 and 82. As described in co-pending International Patent Application PCT / AU03 / 00664, layer 92 is Place along the inside of the molds. After that, the liquid polymer (in this case, the impregnated liquid polymer) is injected into the molds where the polymer impregnated with the slip agents are attached to the layer 92 and then removed from the molds and mounted to a guide or accessory.

As shown in Figure 4, the layer 76 includes a sub-layer 94 comprising the resin-coated glass fiber spirals, which are wrapped around the layer 74 as described in the co-pending International Patent Application PCT / AU03 / 000664 . However, the outermost surface of the layer 94, in general, has a path that makes it extremely difficult to apply paint, coating or aesthetic decals. As shown in Figure 4, the layer 76 is further terminated by applying a sacrificial cap 96 on the layer 94, polishing an outer surface 98 in preliminary form for a smooth finish and then applying an upper layer 100 on the surface 98 to provide the final outer surface 102 of the layer 76, which is smooth and more susceptible to painting, placing stickers on it or coating it by means of additional non-structural layers.

In a particular embodiment, sacrificial layer 96 contains pieces of glass fiber, including glass fiber filaments with a length of about 2 inches. During its application, the pieces of fiberglass form air gaps. The polishing of the layer 96 cuts the air voids to expose a plurality of depressions, small holes or pores 104 along the preliminary surface 98. The upper layer 100 extends over and through the pores 104 to form smooth bridges over the pores 104. The material chosen for the top layer 100 has sufficient rigidity to not weaken in the pores 104 but alternately bridges through the pores. In a particular embodiment, the upper layer 100 contains pieces of fiberglass. Layer 100, in general, has a thickness much less than the thickness of sacrificial layer 96. In a modality wherein layers 96 and 100 each contain pieces of fiberglass, layer 96 has a thickness of up to 0.25 inches. while the upper layer 100 has a maximum thickness of 0.05 inches. The resulting finished surface 102 omits pores or small holes where otherwise concrete is received, which would hinder the cleaning of the outer drum 16. Moreover, the layer 100 further prevents the concrete from depositing in the small holes where it would extend. and would potentially break the surface of the drum 16. In the particular embodiment shown, sacrificial layer 96 is sanded using an abrasive having at least grain size 16. In one embodiment, the sacrificial layer is polished using a sanding belt. of grain size 16.

Above all, the mixer drum 16 is lighter in weight for the volume or aggregate it can load, compared to conventional front discharge steel drums. In addition, because the nozzle part 46 is formed integrally with the main part 44, the drum 16 has a barrel 30 having a continuous and smooth inner surface 58 as well as a relatively smooth and continuous outer surface 54, changing between the main part 44 and the nozzle part 46. As a result, both the inner and outer surfaces of the barrel 30 of the drum 16 lacks joints, corners or other discontinuous surfaces (excluding the drag ring 36 and the projection 32) where the concrete or aggregate can be collected and make cleaning difficult. The ease of cleaning of the drum 16 is furthermore achieved by the use of a polymer impregnated with a slip agent to provide the inner surface 56 of the drum 16. Both the inner surface 58 of the barrel 30, as well as the outer surface 60 of the projections 32 are, at least, partially formed by the impregnated polymer to reduce the coefficient of friction and reduce the adhesion of the concrete. At the same time, the impregnated polymer retains considerably the same physical qualities compared to the non-impregnated polymer.

The exterior surfaces 48, 50 and 54 are also resistant to concrete adhesion and are sufficiently smooth to improve the aesthetic appearance and to facilitate the application of additional aesthetic layers such as paint, coatings or decals. In particular, the sacrificial layer 96 fills and bridges through the longest depressions or valleys along the outside of the layer 94 (provided by means of glass fiber windings wetted with resin). The preliminary exterior surface 98 of sacrificial layer 96 is subsequently sanded for a smoother finish. In a particular embodiment in which the sacrificial layer 96 has pieces of fiberglass, it results in small holes or pores 104 along the preliminary exterior surface 98. The upper layer 100 fills and bridges over those small holes or pores to produce a finished surface 102.

In alternative embodiments, the layer 76 can be terminated with other techniques and / or materials. For example, sacrificial layer 96 can be provided by means of a material that does not result in small holes or pores being polished. In that alternative embodiment, the upper layer 100 can be omitted. In yet another embodiment, the sacrificial layer 96 can be omitted where the exterior of the layer 94 is polished (ie, sanded) and where the upper layer 100 is applied directly to the layer 94. In that application. The layer 94 should preferably have a thickness or strength sufficient to meet the strength requirements of the drum 16 after the portions of the layers 94 are sacrificed.

The drum 16 is shown including a combination of several features in which the performance of the drum 16 is improved synergistically. In other modalities or applications, these characteristics can be used independent of each other or in different combinations. For example, although the layer 74 formed of the polymer impregnated with the slip agent (or alternatively the slip agent impregnated with the strength / durability agent) is shown to be an integral part of both the inner surface 58 of the barrel 30 and the outer surface 60 of the projection 32, in other embodiments, the layer 74 can alternatively form only the inner surface 58 of the barrel 30. In yet another embodiment, the layer 74 can only form the outer surface 60 of the projections 32. Although the layer 74 is shown forming an integral part of the projection 32 with the barrel 30, the projection 43 alternately contains a separately formed structure, which is secured or joined to the barrel 30. In that alternative application, the inner surface 58 of the barrel 30 and the outer surface 60 of the projection 32 may include, one or both, the impregnated polymer.

Although the layer 74 shown is shown being used in a front discharge concrete mixer drum 16, the layer 74 with the polymer impregnated with a slip agent can alternatively be used in a rear discharge drum 116 as shown in Figure 5. -8 and described in the co-pending International Patent Application Series NO. PCT / US03 / 25656. Although the layer 74 is shown being used in a concrete mixer drum (with front discharge or back discharge) formed of at least two helical half-arc sections, which form the interior of the drum, the impregnated polymer can be used alternatively and a drum in which the inner surface 56 of the drum is molded simultaneously. For example, in the mixer drum described in the co-pending International Application Series No. PCT / AU00 / 01226 filed on October 9, 2000 by Anthony Khouri and William Rodgers and titled VEHICLE WITH PLASTIC DRUM MOUNTED TO MIX CONCRETE AND METHOD TO MANUFACTURE IT, which it is incorporated in its entirety for reference, characterized in that the polymer described to provide the inner surface of the drum (unimpregnated polyurethane) can be replaced with a polymer impregnated with a slip agent such as an impregnated polyurethane.

Although the layer 74 formed by the polymer impregnated with a slip agent is described using it in conjunction with an outer layer to the layer 74, which is formed of glass fiber, the layer 74 can alternatively be used in conjunction with an outer layer a the layer 74 formed of one or more different materials. For example, layer 74 may alternatively be used with an additional outer layer to layer 74 formed of a metal. Instead of being molded, the polymer impregnated with the slip agent can alternatively be coated on the layer 76. In one embodiment, the layer 74 can be coated on a layer 76 formed of one or more non-metallic materials such as glass fiber. In another embodiment, the layer 74 can be coated on the layer 76 formed of a metal such as steel.

Although the layer 74 is shown to extend continuously from the terminal portion 40 to the terminal portion 42, the layer 74 may be alternately molded into sections, which does not extend from the terminal portion 40 to the terminal portion 42 or may be coated or applied. otherwise the layer 76, which by itself does not extend continuously from the terminal part 40 to the terminal part 42. For example, the layer 76 may alternatively be formed of annular sections (but for the terminal part 42 which shall be closed) formed of a non-metallic material such as fiberglass or a metallic material such as steel, which are joined or secured together. In this application, the layer 74 can be coated on the annular sections, by means of dew, either after assembling the sections together or before assembling the sections together or they can be secured to the sections after the sections are Ensure each other or before the sections secure each other. In one embodiment, the layer 74 can be formed as a section and can be secured to the layer 76, which is in sections to overlap or bridge through the seams between the sections of the layer 76 along the inside of the drum to improve the resistance. As mentioned above, in these applications where the structural requirements of the layer 74 are less stringent, as when the layer 74 is coated or sprayed on an existing drum, the amount or percentage of the slip agent impregnated in the polymer can be increased.

Although the projection 32 is shown with the shape and configuration shown in Figures 2 and 3, the projection 32 may have other alternative configurations and may be formed by other techniques. For example, the projection 32 can be configured and formed alternately as shown in U.S. Patent Application. copending Series No. 10 / 049,605, which is hereby incorporated in its entirety for reference. In yet another embodiment, the projection 32 can be formed with other materials and other processes.

Although the finishing process is described with respect to Figure 4 is shown in conjunction with the exterior finish of barrel 30 of drum 16, this finishing process can also be used in other drums having an exterior surface (before applying paint , stickers and the like) that is provided with fiberglass or other materials that result in a relatively rough textured surface. For example, the finishing process can also be used to terminate the outer surface of the drum formed in accordance with U.S. Patent Application. copending Series No. 10 / 049,605, which is hereby incorporated in its entirety for reference. Although the entire outer surface of the barrel 30 of the drum 16 is described as being completed according to the process described with respect to Figure 4, this finishing process can alternatively also be formed along selected areas only from the surface of the barrel. .

Figures 5-8 show a concrete mixer truck 110 having a front discharge drum 116 having an inner layer of the drum 134, which includes an impregnated slip agent such as a polydecene or a polyalphaolefin fluid or a polytetrafluoroethylene. The concrete mixer truck 110 includes a chassis 112, a car zone 114, a drum mixer 116, and a drive train of the mixer drum 118. The chassis 112 includes a frame 120, a power source 122, a drive train 124, and wheels 126. The frame 120 provides the mixer truck 110 with a structural support and the rigidity necessary to carry heavy loads of concrete. The power source 122 is coupled to the frame 120 and generally consists of a source of rotational mechanical energy, which is derived from a stored energy source. Examples include, but are not limited to, a gas-fired internal combustion engine, a diesel engine, turbines, fuel cell-driven engines, electric motor or any other type of motor capable of providing mechanical power.

The drive train 124 engages between the power source 122 and the wheels 126 and transfers energy (or movement) from the power source 122 to the wheels 126 to drive the truck 110 in a forward and backward direction. The drive train 124 includes a transmission 125 and a reduction unit at the end of the wheel 127. Both the transmission 125 and the reduction unit at the end of the wheel 127 use a series of gear sets to adjust the transmitted torsion. by the power source 122 to the wheels 126. An example of a reduction unit at the end of the wheel is described in the US Patent Application. Copendent Series No. 09 / 635,579, filed August 9, 2000, by Brian K. Anderson entitled "NON-CONTACT SPRING GUIDE", which is incorporated herein by reference in its entirety.

The cockpit area 114 engages the chassis 112 and includes a closed area from which the truck operator 110 handles and controls at least some of the various functions of the truck 110.

The control unit or control train 118 is operatively coupled to the power source 112 and the mixing drum 116 and uses the energy or movement of the power source 122 to provide a rotational force or torsion to the mixing drum 116. According to an alternative mode, the drive train may have another source of energy different from the power source 112 that is provided in the truck 110.

Referring now to Figure 7, the mixing drum 116 includes a barrel 133, projections 132, ramps 140, a removable cover assembly 137 or 300, a driving ring 139, and a roller ring 135. The barrel 133, in general , is a pear shaped drop container having an opening 128 at one end (the smallest end) and a drag ring 139 (described below) coupled to the other longer end 130 or to the barrel 133. The barrel 133 it includes an inner layer of the drum 134 and an outer layer of the outer drum 136. The inner layer of the inner drum 134 is made of two spiral shaped sections 141 and 143 which are "screwed" or coupled together. Each of sections 141 and 143 is a substantially planar board that spirals about an axis that becomes the central axis 131 of barrel 133 when sections 141 and 143 are fully assembled. Each of the sections 141 and 143 has a width W which extends substantially parallel to the axis 131 of the barrel 133 (or which extends, generally, along the central axis) and a length that substantially circumscribes or circulates the axis 131 According to an example embodiment, the width of each section varies along the section length, for example, from between about 6 inches and 36 inches. Each of the sections 141 and 143 have a first edge 147 extending along the section and a second edge 149 extending the length of the section. Each of the sections 141 and 143 is coiled about the axis 131 of the barrel 133 so that there is a gap between the first edge 147 of the section and the second edge 149 of the same section. This gap provides the space that will fill the other section when it is attached or screwed to the first section. Accordingly, when the sections 141 and 143 are assembled together to form the inner layer of the drum 134, the edge 147 of the section 141 will join the edge 149 of the section 143 and the edge 149 of the section 141 will join the edge 147 of section 143. A seam 158 is formed where the edges of sections 141 and 143 join together.

Once the two sections of the inner layer of the drum 34 have been assembled, the outer layer of the drum 136 is formed as a continuous layer around the outermost surface of the innermost drum layer. Accordingly, the outer layer of the drum 134 extends continuously from one end portion of the barrel to the other and encompasses the seams between the sections 141 and 143. The outermost drum layer 136 is a structural layer made of a reinforced composite material. fiber applied by means of windings of resin-coated fibers around the outermost surface of the innermost drum layer 134. According to a modality, the resin is Hetron 942, available from Ashland Chemical, in Dublin, Ohio, and the fibers are glass fibers, preferably 2400 Tex E Glas (approximately 206 yards / pound). According to one embodiment, the angle at which the fibers are wound around the drum on the main shaft (the place where the barrel 133 has the largest diameter) is approximately 10.5 degrees relative to the axis 131 of the barrel 133. During the winding process, the resin coated fibers are wrapped, in general, from one terminal part of the drum to the other. According to one embodiment, the fibers are provided in a ribbon or bundle that is approximately 25 millimeters wide and include 64 filaments. The fiber batten is wrapped around the drum if it overlaps approximately 50% between each step of the batten. The fiber wrap from the terminal to the terminal part helps to provide the drum 116 with the structural support to withstand the various forces that are applied to the drum 116 in a variety of different directions.

According to an example embodiment, the projections 132 and the ramps 140 are integrally formed in a single unitary body with the sections 141 and 143. Each of the sections 141 and 143, and the corresponding projections and ramps, are formed through a polyurethane injection molding process impregnated with a slip agent, and the outer layer of the drum 136 is made using resin-coated glass fiber fibers. According to other alternative embodiments, the inner layer of the drum and / or the outer layer of the drum can be made from one or more varieties of different materials, including but not limited to, polymers, elastomers, rubbers, ceramics, metals, composites, etc. . According to other alternative embodiments, other processes or components can be used to build the drum. For example, according to several alternative embodiments, the inner layer of the drum can be formed as a single unitary body, or of any number of separate parts, components, or sections. According to other alternative embodiments, the inner layer of the drum, or any of the sections forming part of the inner layer of the drum, can be manufactured using other methods or techniques.

Referring still to Figure 7, the projections 132a and 132b engage the sections 141 and 143, respectively, and extend internally toward the central axis 131 of the barrel 133 and along the length of the respective section. Accordingly, two substantially identical protrusions 132a and 132b are coupled to the inner layer of the drum 134 and spirally about the inner surface of the inner layer of the drum 134 in the form of a half-arc spiral. In one embodiment, the protrusion 132a and 132b extends from an axial end of the barrel 133 through an axial midpoint of the barrel 133. The protrusions 132a and 132b are spaced in circumference about the axis 131 by approximately 180 degrees. Because the projections 132a and 132b are substantially identical, subsequent references to the projections will only be made as "projection 132" when any projection (or both) 132a and 132b are mentioned.

A projection and one or more ramps are coupled to each section of the inner layer of the drum 134. Because the projection and ramp (s) that are attached to each section include substantially identical features and elements, where appropriate, the description will be described. Outgoing and ramps that are attached to a section, it is understood that the projection and ramps of the other section are considerably identical. Figure 4 shows in more detail the projection 132 and ramps 140a and 140b, which are coupled to section 141.

The projection 132 (i.e., fin, propeller, vane, screw, formation, etc.) includes a base part 142, an intermediate part 144, and a terminal part 146. The base part 142 extends inwardly from the section 141 towards the drum axis 116 and serves as a transition area between section 141 and intermediate part 144 of projection 132. The transition area is beneficial as it has to reduce fatigue concentrations in the base part 142 that may result from the application of force to the projections 132 by the concrete. The reduction of fatigue concentrations tends to reduce the probability that the projection 132 fails due to fatigue. To provide the transition area, the base part 142 has a rounded or tapered section on each side of the boss 132 to provide a gradual transition from the section 141 to the intermediate part 144. To minimize any unwanted concrete buildup, the curve it is preferably greater than 10 millimeters. According to an example embodiment, the curve is approximately 50 millimeters. According to another embodiment, the curve begins on each side of the projection 132 close to the section 141 approximately three inches from the center line of the projection 132 and ends approximately five inches above the height H of the projection 132, proximal to the intermediate zone 144 of the projection 132. Because the drum 116 rotates, the orientation of any particular section of the projection 132 changes constantly. Accordingly, to simplify the description of the projection 132, the term "height", when used in reference to the projection 132, will refer to the distance of the projection 132 extending internally towards the central axis of the drum 116, measured from the center of the base part near the section 141 to the tip of the terminal part 146. It will be noted, however, that the height of the projection 132 changes along the length of the projection 132. Consequently, the places where the curve or decreasing section begins and / or ends, the distance over which the curve or decreasing section extends, may vary depending on the height and / or location of any particular part of the projection. According to several alternative modalities, the curve of the base zone may be constant or may vary. According to other alternative embodiments, the transition between the section and the intermediate part of the projection may be beveled or may take the form of some other gradual transition. Moreover, the places where the transition or decreasing section can begin or end can vary depending on the material used, the thickness of the inner wall of the drum, the height of the projection, the load that will be placed on the ledge, the location of a particular part of the projection inside the drum, and a variety of other factors.

According to any example embodiment, the characteristics of the decreasing section must allow the projection to flex at least partially under the loads applied by the concrete. However, if the decreasing section allows the projection to flex too much, the projection can be fatigued very fast. On the other hand, if the decreasing section does not allow the projection to flex sufficiently, the strength of the concrete in the projection may leverage into the inner layer of the drum 134 and potentially tear the inner layer of the drum out of the outer layer of the drum.

The intermediate part 144 of the projection 132 extends between the base portion 142 and the end portion 146. According to one embodiment, the intermediate portion 144 has a thickness of approximately six millimeters and is designed to flex when the force of the insert is applied. concrete.

The terminal part 146 of the projection 132 extends from the intermediate part 144 to the drum axis 116 and includes a support member 148 and spacers 150. The thickness of the end portion 146 is, in general, greater than the thickness of 1. intermediate part 144. Depending on where a particular section of the end portion is provided along the length of the projection 132, the added thickness of the end portion 146 may be centered over the intermediate portion 144 to compensate sideways or towards the other. In some areas along the length of the projection 132, the terminal part 146 is provided only on one side of the intermediate part 144 (i.e., the side closest to the opening 128 or the side closest to the terminal part). 130). In that configuration, the terminal portion 146 acts as a flange or flange that extends over one side of the intermediate portion 144 and serves to improve the ability of the projection 132 to move or mix the concrete that is in contact with the side or part. intermediate 144, on which the terminal part 146 extends. Due to the increase in the thickness of part 1 terminate 146, relative to the intermediate part 144, the terminal part 146 includes a transition zone 145 which provides a gradual transition of 1 part intermediate 144 to the terminal part 146. According to an example embodiment, the transition zone is rounded. According to alternative modalities, the transition zone can be beveled or of decreasing section. To minimize any wear or build-up that may occur as a result of the passage of the concrete on the terminal portion 146, the projection 132 terminates at a rounded edge 152.

According to several alternative modalities, each of the base, intermediate and terminal regions may have different sizes, shapes, thicknesses, lengths, etc., depending on the particular situation or circumstances in which the drum is used.

Figure 8 shows the support member 148 in greater detail. As shown in Figure 8, the support member or torsion bar 148 is an elongated circular bar or beam that is nested within the terminal portion 146 of the boss 132 to provide structural support to the boss 132. The torsion bar 148 it has a shape corresponding to the expiratory shape of the projection 132 and extends along the length of the projection 132. The terminals of the bar 148 have flared fibers which are nested in the inner layer of the drum 134. The bar twist 148 serves to considerably restrict the ability of the terminal portion 146 of the boss 132 to flex when a load is applied to the boss 132 by the concrete, and thus prevent the boss 132 from bending or bending over the concrete. Although it is rigid enough to support the projection 132, the torsion bar 148 is preferably flexible by twisting. The torsional flexibility of the torsion bar 148 allows it to withstand the torsional loads that result from some deflection of the terminal part 146 of the projection 132. According to an exemplary embodiment, the support member 148 is of a composite material that is made primarily of carbon or graphite fibers and a urethane-based resin. According to one example embodiment, the ratio of the carbon fibers to the urethane-based resin is 11 pounds of carbon fiber per 9 pounds of urethane-based resin. An example of the urethane-based resin is Erapol EXP 02-320, available from Era Polymers Pty Ltd in Australia. According to alternative embodiments, the support member can be made of any combination of materials that allow the support member to provide the desired structural support and at the same time allow the torsion bar to withstand the torsional loads applied thereto. . For example, the torsion bar can be made from one or more fiberglass fibers and esters based resins. According to other alternative embodiments, the size and shape of the support member may vary depending on the particular circumstances in which the support member is used.

According to an example embodiment, the support member 148 is made through a pultrusion or stretch extrusion process. The pultrusion process includes the steps of collecting a bundle of fibers, passing the fibers through a resin bath, and then pulling the resin-coated fibers through a tube. The support member 148 is then wrapped around a mandrel in an appropriate manner and allowed to set to give the support member 148 the desired shape. The fibers pull through the tube by means of a winch cable which is passed through the tube and coupled to the fibers. To facilitate the coupling of the cable to the fibers, the fibers are bent and the cable is joined to the loop created by the bent fibers. The lathe pulls the cable back through the tube, which, in turn, pulls the fibers through the tube. According to one example embodiment, the urethane-based resin through which the fibers are passed before entering the tube is injected into the tube at various points along the length of the tube when the fibers are pulled. through the tube. According to alternative embodiments, the support member can be made from one or more of a variety of different processes.

According to an example embodiment, the projection 132 and the ramps 140 are integrally formed with each of the sections 141 and 142 as a single unitary body and are made along with the sections 141 and 142. As shown in FIG. described above, each of sections 141 and 143, and corresponding projection 132 and ramps 140, are preferably made through an injection molding process during which an elastomer is injected between molds. To nest the support member 148 within the terminal portion 146 of the projection 132, the support member 148 is placed in a mold that defines the shape of the projection 32 before injecting the elastomer. In order to keep the support member 148 in the proper place within the mold during the injection process, the spacers, which are shown as helical springs 150, wrap around the circumference of the support member 148 and spaced intermittently along the length of the support member 148. the length of the support member 148. Each spring 150 is retained around the circumference of the support member 148 by connecting one end portion of the spring 150 to the other. When the support member 148 and the springs 150 are placed in a mold prior to the injection process, the springs 150 are in contact with an internal surface of the mold 154 and therefore retain the support member 148 in the proper place within the mold. mold.

When the elastomer is injected into the molds, the elastomer flows through the spring 150 and surrounds (ie, incorporates, encapsulates, etc.) each of its coils. As a result, there is a continuous flow of the elastomer through the spring 150, such that if the elastomer does not securely join the coils of the spring 150, the areas along the projection 132 where the springs 150 are placed are not significantly more weaker than the areas along the projection 132 when there are no spring spacers 150. According to various alternative embodiments, other materials and structures can be used as spacers. For example, the spacer can be made from one or more varieties of materials including polymers, elastomers, metals, ceramics, wood, etc. The spacer can also have a variety of different shapes and configurations, including but not limited to, circular, rectangular, triangular, or any other shape. Moreover, the spacer may not substantially wrap the support member, but may include one or more members that are provided intermittently around the periphery of the support member. According to other alternative embodiments, the spacer may be a flat disc or a cylinder having an outer diameter that is in contact with the internal surface of the mold and an opening through which the support member passes. The flat disc or cylinder may also include a plurality of openings extending therethrough to allow a continuous flow of the injected elastomer through at least some areas of the disc.

Although the present invention has been described with reference to exemplary embodiments, workers skilled in the art will recognize that changes can be made in form and detail without departing from the spirit and scope of the invention. For example, although different example embodiments have been described including one or more features providing one or more benefits, it is contemplated that the described features may be exchanged with each other or alternatively combined with each other in the described example embodiments or in other alternative embodiments. Because the technology of the present invention is relatively complex, not all changes in technology are predictable. The present invention is described with reference to the exemplary embodiments and the provisions of the following claims are intentionally stated as broad as possible. For example, unless otherwise specified, the claims cite a particular individual element, it also encompasses a plurality of those particular elements.

Claims (58)

1. A rotating concrete mixing drum is described, which consists of: an interior surface at least partially provided by a polymer impregnated with a slip agent.

2. The drum of claim 1, characterized in that the polymer includes polyurethane.

3. The drum of claim 1, characterized in that the sliding agent has a surface energy lower than the surface tension of a low-slump concrete of Portland Cement.

4. The drum of claim 1, characterized in that the sliding agent has a surface energy of less than 20 dynes per centimeter.

5. The drum of claim 1, characterized in that the sliding agent is a polydecene.

6. The drum of claim 1, characterized in that the sliding agent is a polyalpha olefin fluid.

7. The drum of claim 1, characterized in that the sliding agent is a polytetrafluoroethylene.

8. The drum of claim 1, characterized in that the polymeric material is a polyurethane, wherein the slip agent is a polytetrafluoroethylene and wherein at least 2% the weight of the impregnated polymer is polytetrafluoroethylene.

9. The drum of claim 8, characterized in that no more than 5% by weight of the polymer impregnated along the surface is polytetrafluorooethylene.

10. The drum of claim 1, characterized in that the polytetrafluoroethylene is about 2% by weight of the polymer impregnated along the surface.

11. The drum of claim 1, characterized in that the polymer is polyurethane, and wherein the slip agent is a polyalphadefine.

12. The drum of claim 11, characterized in that no more than 5% by weight of the impregnated polymer is polyalphaolefin.

13. The drum of claim 12, characterized in that at least 2% by weight of the impregnated polymer is polyalphaolefin.

14. The drum of claim 11, characterized in that at least 2% by weight of the impregnated polymer is the polyalphaolefin.

15. The drum of claim 11, characterized in that the polyalphaolefin contains about 3% by weight of the impregnated polymer along the surface.

16. The drum of claim 1, characterized in that the sliding agent is configured not to migrate considerably within the polymer.

17. The drum of claim 1 includes: an inner layer containing the impregnated polymer along the inner surface; and an outer layer that provides an outer surface of the drum.

18. The drum of claim 17, characterized in that the outer layer is not metallic

19. The drum of claim 18, characterized in that the outer layer consists of fiberglass.

20. The drum of claim 19, characterized in that the outer layer includes: fiberglass windings near the inner layer; a first layer of pieces of fiberglass on the windings, the first layer has a polished surface with pores; and a second layer of pieces of fiberglass on the first layer and through the pores.

21. The drum of claim 20, characterized in that the first layer has a first thickness and wherein the second layer has a smaller thickness.

22. The drum of claim 20, characterized in that the second layer has a thickness of about 0.25 inches and wherein the second layer has a thickness of about 0.05 inches.

23. The drum of claim 20, characterized in that the second layer has a thickness of about 0.1 inches.

24. The drum of claim 20, characterized in that the polished surface is smooth because it is polished with a grain size 16 abrasive.

25. The drum of claim 1, characterized in that the outer layer includes: fiberglass windings near the inner layers; a sacrificial layer on the windings, characterized in that the sacrificial layer has a surface with pores; and an upper layer on the sscrificial layer and through the pores.

26. The drum of claim 17, characterized in that the outer layer is metallic.

27. The drum of claim 1, characterized in that the impregnated polymer has a tensile strength of at least 15 MPa.

28. The drum of claim 1, characterized in that the impregnated polymer has a 300% modulus of at least 12 MPa.

29. The drum of claim 1, characterized in that the impregnated polymer has a tear resistance of at least 68 N / m.

30. The drum of claim 1 includes inwardly extending projections, configured to move the material when the drum is rotated, characterized in that the projections partially provide the inner surface of the drum.

31. The drum of claim 30, characterized in that the projections have an outer surface that includes the impregnated polymer.

32. The drum of claim 31, "characterized in that at least a portion of one of the projections has a thickness formed entirely of the impregnated polymer.

33. A fin for use in a concrete mixer drum, the fin in: an outer surface at least partially provided by a polymer impregnated with a slip agent.

34. A barrel drum for a concrete mixing drum, the barrel consists of: An interior surface at least partially provided by a polymer impregnated with a slip agent.

35. A method to form a concrete mixing drum, the method consists of: Impregnate a polymer with a sliding agent; and Form an interior surface of a concrete mixing drum with the impregnated polymer.

36. The method of claim 35 includes molding the impregnated polymer.

37. The method of claim 35 includes spraying the impregnated polymer.

38. The method of claim 35, characterized in that the slip agent includes polytetrafluoroethylene.

39. The method of claim 37, characterized in that the impregnation includes mixing the polytetrafluoroethylene powder with polyol.

40. The method of claim 39, characterized in that mixing consists of high mixing by cutting.

41. The method of claim 40 wherein mixing is performed using a Cowles propeller mixer.

42. The method of claim 35 includes: molding the impregnated polymer in a first section; forming the inside of the drum with the section; and apply fiberglass to the outside of the first section.

43. The method of claim 42 includes: molding the impregnated polymer in a second section; coupling the second section to the first section to form the interior of the drum; and apply fiberglass windings to the outside of the second section.

44. The method of claim 43 wherein the first section and the second section are helical and wherein the coupling includes screwing the first section and the second section together.

45. The method of claim 43 includes: applying a sacrificial layer of glass FIBA on the windings; polishing the sacrificial layer to form a polished outer surface having pores; and apply a top layer of fiberglass on the polished outer surface.

46. A method for the exterior finishing of a concrete mixer drum having a preliminary exterior surface, the method consists of: applying a sacrificial layer of fiberglass on the preliminary exterior surface; polishing the sacrificial layer to form a polished surface having pores; and apply a top coat on the polished surface, over the pores.

47. The method of claim 46 wherein the sacrificial layer is polished using an abrasive having at least grain size 16.

48. The method of claim 46 wherein the top layer is of pieces of fiberglass.

49. The method of claim 48 wherein the top layer has a thickness of less than 0.50 inches.

50. A concrete mixer truck consisting of: a chassis; a cabin supported by the chassis; a drum supported by the chassis and extending over the cabin, the drum has the first section extending in a half-arc spiral along an axial center line of the drum; and • a second section extending in a half-arc spiral along the axial center line of the drum, characterized in that the first section and the second section extend adjacent to each other.

51. A concrete mixer truck that consists of: a barrel that have an internal surface and an external surface; and at least one spiral projection extending along the internal surface, characterized in that the inner surface is provided by means of a polymer and wherein the outer surface has a convex part and a concave part.

52. The drum of claim 51, characterized in that the concave part is located along the axial central section of the drum.

53. The drum of claim 51, characterized in that the convex part and the concave part are formed integrally as a single unitary body.

54. The drum of claim 53 characterized in that the convex part and the concave part are formed of fiberglass windings.

55. The drum of claim 51, characterized in that the internal surface is at least partially provided by means of a first half-arc section.

56. The drum of claim 51 characterized in that the projections are formed integrally as a single unitary body with the inner surface of the barrel.

57. The drum of claim 55 characterized in that the inner surface is provided by means of a second half-arched section screwed near the first section, wherein the first section and the second section have a concave surface in the outer middle part.

58. A rotating concrete mixing drum, consisting of an interior surface partially provided by means of a material including a slip agent or strength-durability agent impregnated within another slip agent or agent for strength / durability.