Patent Publication Number: US-7585105-B2

Title: Scraper assembly

Description:
BACKGROUND OF THE INVENTION 
     The technology of the present invention generally relates to scraper assemblies and methods for assembling scraper assemblies. Particularly, the present technology relates to scraper assemblies used in commercial blending and/or cooking systems and methods for assembling such scraper assemblies. 
     Commercial blending and/or cooking systems are known in the food preparation industry and other industries. For example, U.S. Pat. No. 4,733,607 (the “&#39;607 patent”), which issued to Star et al. on Mar. 29, 1988, and is entitled Food Processing Machine, describes “[a] mixer for food products and the like in commercial quantities [that] comprises a horizontally elongated body with a trough bottom in which rotates one or more horizontal drive shafts carrying an agitator in the form of a helical ribbon or worm of a radius matching that of the trough bottom. The ribbon supports a number of scraper units on it, each scraper unit including a scraper body having a broad face facing toward the trough bottom, the broad face terminating in two opposed relatively sharp edges. The scraper bodies are mounted for rocking movement so that the leading edge will be forced into scraping engagement with the trough bottom and will remain in engagement with the trough bottom even though the trough is wavy or uneven. Either of the edges of the scraper body can be the leading edge, depending on the direction of rotation of the agitator drive shaft.” (&#39;607 patent at Abstract.) 
     In another example, U.S. Pat. No. 5,228,775 (the “&#39;775 patent”), which issued to Horn et al. on Jul. 20, 1995, and is entitled Reversing Blender Agitators, describes “[i]mproved methods of operating batch or continuous blenders having tub and two agitators extending parallel to each other, each agitator having horizontal shaft and agitator ribbon wound helically around the shaft.” (&#39;775 patent at Abstract (references to Figures omitted).) The &#39;775 patent further states, “The agitators are rotated in opposite directions to fold the product into the center of the tub for mixing, with both agitators moving the product in the same direction lengthwise in the tub. The agitators&#39; rotation direction is periodically reversed, with the time of reversed operation in each cycle being less than the time of forward operation, so that the product as a whole progressively moves toward discharge end of the blender as the product is being mixed. When needed, scrapers are attached to the agitator ribbons to scrape the wall of the tub upon rotation of the agitators in either direction.” (&#39;775 patent at Abstract (references to Figures omitted).) 
     Although scraper assemblies that are currently available provide a certain degree of effectiveness, they have shortcomings. For example, currently available scraper assemblies allow for potential contamination and/or reduced productivity. Particularly, currently available scraper assemblies have spaces where food can get stuck, and may not be readily removed without deconstructing the scraper assembly. This can result in the contamination of new food items with remnants of previously processed food items and/or reduced productivity due to an increased need for system maintenance, such as removal and cleaning of scraper assemblies, which oftentimes requires special tools, such as a torque wrench. 
     Further, some scraper assembly designs have many discrete parts that can come loose and eventually become mixed in with food items. This creates the potential for downstream contamination in systems that feed into larger repositories as well as the potential to damage equipment used in commercial blending and/or cooking systems. 
     Finally, scraper assembly designs known in the art do not sufficiently maintain contact between scraper heads and the inner surface of tubs, which results in uneven scraping and increased sticking of substances, such as food items, to the inner surface of tubs. 
     Thus, there is a need for an improved scraper assembly for use in commercial blending and/or cooking systems. Particularly, for a scraper assembly that reduces the risk of contamination, scrapes tubs more evenly and allows for easier removal and/or replacement of scraper assembly components. 
     BRIEF SUMMARY OF THE INVENTION 
     Certain embodiments of the present invention provide a scraper assembly for use in a blending system and a method for assembling a scraper assembly. For example, in one embodiment, a scraper assembly for use in a blending system comprises: a substantially rigid member; a pin with a first end and a second end, wherein a tab protrudes from a side of the first end and the second end is attached to the substantially rigid member; a scraper head having at least one scraping surface, wherein the scraper head has a hole therethrough that is large enough to receive the pin, wherein the scraper head has a first channel that runs the depth of the scraper head and is large enough to receive the tab, and wherein the scraper head has a second channel that does not run the depth of the scraper head and is large enough to receive the tab; and a coil spring, wherein the coil spring is disposed around the pin and is held captive between the substantially rigid member and the scraper head. 
     As another example, one embodiment of a blending system comprises: a tub having an inner surface; an agitator having a shaft and a ribbon wound helically around the shaft, wherein the agitator is disposed within the tub such that the agitator can be rotated about the shaft without contacting the inner surface of the tub; and a scraper assembly comprising: a substantially rigid member, wherein the substantially rigid member is attached to the ribbon; a pin with a first end and a second end, wherein a tab protrudes from a side of the first end and the second end is attached to the substantially rigid member; a scraper head having at least one scraping surface, wherein the scraping surface contacts the inner surface of the tub, wherein the scraper head has a hole therethrough that is large enough to receive the pin, wherein the scraper head has a first channel that runs the depth of the scraper head and is large enough to receive the tab, and wherein the scraper head has a second channel that does not run the depth of the scraper head and is large enough to receive the tab; and a coil spring, wherein the coil spring is disposed around the pin and is held captive between the substantially rigid member and the scraper head. 
     As another example, one embodiment of a method for assembling a scraper assembly comprises: providing a substantially rigid member with a pin attached thereto, wherein the pin has a tab protruding from a side of the end of the pin that is not attached to the substantially rigid member; providing a coil spring; winding the coil spring onto the pin by winding the coil spring around the tab until the coil spring is held captive between the substantially rigid member and the tab; providing a scraper head having at least one scraping surface, wherein the scraper head has a hole therethrough that is large enough to receive the pin, wherein the scraper head has a first channel that runs the depth of the scraper head and is large enough to receive the tab, and wherein the scraper head has a second channel that does not run the depth of the scraper head and is large enough to receive the tab; aligning the scraper head with the pin such that the tab is aligned with the first channel; sliding the scraper head onto the pin, thereby compressing the coil spring, until the tab passes through the scraper head; aligning the scraper head with the pin such that the tab is aligned with the second channel; and releasing the scraper head, thereby allowing the coil spring to decompress. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of one embodiment of an agitator and scraper assemblies. 
         FIG. 2  is a side view of one embodiment of an agitator and scraper assemblies. 
         FIG. 3  is an end view of one embodiment of an agitator and scraper assemblies. 
         FIG. 4  is a perspective view of one embodiment of a scraper assembly. 
         FIG. 5  is a side view of one embodiment of a scraper assembly. 
         FIG. 6  is a bottom view of one embodiment of a scraper assembly. 
         FIG. 7  is an exploded view of one embodiment of a scraper assembly. 
         FIG. 8  is a perspective view of one embodiment of a scraper head. 
         FIG. 9  is a bottom view of one embodiment of a scraper head. 
         FIG. 10  is a top view of one embodiment of a scraper head. 
         FIG. 11  is a perspective view of one embodiment of agitators and scraper assemblies disposed within a tub. 
         FIG. 12  is a top view of one embodiment of agitators and scraper assemblies disposed within a tub. 
     
    
    
     The foregoing summary, as well as the following detailed description of embodiments of the present invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, certain embodiments are shown in the drawings. It should be understood, however, that the present invention is not limited to the arrangements and instrumentality shown in the attached drawings. 
     DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS 
       FIGS. 1-3  illustrate embodiments of an agitator  6  and scraper assemblies  8  used in accordance with the present technology.  FIG. 1  is a perspective view of one embodiment of an agitator  6  and scraper assemblies  8 ;  FIG. 2  is a side view of one embodiment of an agitator  6  and scraper assemblies  8 ; and  FIG. 3  is an end view of one embodiment of an agitator  6  and scraper assemblies  8 . 
     In the embodiments shown in  FIGS. 1-3 , the agitator  6  includes a cylindrical shaft  10 , spokes  12  and a ribbon  14 . The shaft  10 , spokes  12  and ribbon  14  are preferably made of steel, but can also be made of other materials with steel-like characteristics. The ribbon  14  is wound helically around the shaft  10  and attached thereto by the spokes  12 . The spokes  12  are attached to the shaft  10  and are also connected to the ribbon  14 . The shaft  10 , spokes  12  and ribbon  14  are preferably attached by welding. 
     In the embodiments shown in  FIGS. 1-3 , an agitator  6  can be used in connection with a tub, a vat or other container to blend substances. From this point on, any reference herein to a tub is also a reference to a vat or other container. Specifically, the agitator  6  can be rotated about the shaft  10  in order to rotate the spokes  12  and ribbon  14 , thereby blending substances in a tub (not shown). For example, in one embodiment, a tub is a food receptacle and the substances to be blended are food items. Substances that are blended in a tub can stick to the inner surface of the tub, that is, the surface of the tub that contacts the substances that are being blended. Also, such sticking can be enhanced by the heating or cooling of the inner surface of the tub. Thus, it is desirable to scrape the inner surface of a tub during blending in order to remove substances that stick to the inner surface of the tub. 
     Examples of systems in which agitators can be used with tubs to blend substances include systems such as those described in U.S. Pat. No. 4,733,607, which issued to Star et al. on Mar. 29, 1988 and is entitled Food Processing Machine, and U.S. Pat. No. 5,228,775, which issued to Horn et al. on Jul. 20, 1995 and is entitled Reversing Blender Agitators. 
     In the embodiments shown in  FIGS. 1-3 , the scraper assemblies  8  are attached to the agitator  6 . Specifically, the scraper assemblies  8  are attached to the ribbon  14  by a substantially rigid member  16 . The substantially rigid member  16  is preferably welded to the ribbon  14  of the agitator  6 . The substantially rigid member  16  is preferably attached to the ribbon  14  such that the substantially rigid member  16  is substantially parallel to the shaft  10  of the agitator  6 . Further, each scraper assembly  8 , as shown, includes a scraper head  18 . The scraper head  18  is preferably configured to contact the inner surface of a tub (not shown). In various embodiments, a substantially rigid member that extends from a ribbon of an agitator, which agitator includes a shaft and a ribbon, is not substantially parallel to the shaft of the agitator. In such embodiments, the remaining components of the scraper assembly are configured such that the scraper head contacts the inner surface of a tub. 
     In the embodiment shown in  FIG. 2 , the scraper heads  18  are spaced such that, together, they span a distance x. In a preferred embodiment, the distance x is equal to the distance covered by the ribbon  14 . In a preferred embodiment, the distance x is also equal to the length of a tub (not shown). The spacing of the scraper heads  18 , as shown in  FIG. 2 , allows the entire distance x to be scraped once for every full rotation of the agitator  6  in either direction a or direction b. When the agitator  6  is rotated in direction a or direction b, the scraper heads  18  can rock somewhat, which can allow the scraper heads  18  to maintain contact with the inner surface of a tub (not shown). 
     The embodiment shown in  FIG. 2 , has five scraper assemblies  8 . In a preferred embodiment using five scraper assemblies, each scraper head  18  is about eight inches long and about two inches wide. In various embodiments, any number of scraper assemblies may be employed to cover a given distance. That is, the shorter the scraper heads, the more scraper assemblies that will be required to cover the same distance. Likewise, the longer the scraper heads, the fewer scraper assemblies that will be required to cover the same distance. Scraper heads need not be eight inches long and two inches wide and scraper heads need not be proportioned such that the length is four times the width. That is, scraper heads can come in any length and width that is sufficient for a given application. For example, it may be desirable to vary scraper head length and/or width based on what substances are being blended and/or the size of a tub. In various embodiments, scraper heads of different sizes can be used for a given application. 
     In the embodiment shown in  FIG. 3 , the scraper heads  18  protrude beyond the ribbon  14 . It is preferred that the scraper heads  18 , and not the ribbon  14 , contact the inner surface of a tub (not shown). The clearance between the ribbon  14  and a tub (not shown) can vary due to imperfections in the inner surface of a tub. Likewise, the distance the scraper head  18  protrudes beyond the ribbon  14  can vary with the actual clearance between the ribbon  14  and a tub (not shown). For example, in one embodiment, the scraper head  18  protrudes about 3/16 of an inch beyond the ribbon  14  and, thus, there is about 3/16 of an inch of clearance between the ribbon  14  and the tub (not shown). In such an example, the clearance between the ribbon  14  and the tub (not shown) can vary, thereby becoming greater and/or less than 3/16 of an inch, due to imperfections in the inner surface of the tub. In such an example, when the clearance between the ribbon  14  and the tub (not shown) becomes greater than 3/16 of an inch, the scraper head  18  can deflect in a direction x, thereby decompressing a spring  20 , in order to maintain contact with the tub (not shown). In such an example, when the clearance between the ribbon  14  and the tub (not shown) becomes less than 3/16 of an inch, the scraper head  18  can deflect in a direction y, thereby compressing a spring  20 , in order to maintain contact with the tub (not shown). In various embodiments, the clearance between a ribbon  14  and a tub can be greater or less than 3/16 of an inch. 
       FIGS. 4-6  illustrate embodiments of scraper assemblies used in accordance with the present technology.  FIG. 4  is a perspective view of a scraper assembly;  FIG. 5  is a side view of a scraper assembly; and  FIG. 6  is a bottom view of a scraper assembly. In the embodiments shown in  FIGS. 4-6 , a scraper assembly  8  includes a substantially rigid member  16 , a scraper head  18 , a coil spring  20 , a pin  22  and a keeper  24 . The substantially rigid member  16  is attached to the pin  22 . The substantially rigid member  16  is preferably welded to the pin  22 . The substantially rigid member  16  is preferably attached to the pin  22  such that the pin  22  is substantially perpendicular to the substantially rigid member  16 . The keeper  24  is attached to the pin  22 . The keeper  24  is preferably welded to the pin  22 . The keeper  24  is preferably attached to the pin  22  such that the keeper  24  is substantially parallel to the substantially rigid member  16  (shown in  FIG. 4 ) and both ends of the keeper  24  protrude beyond the outer wall of the pin  22  (shown in  FIG. 6 ). 
     In the embodiment shown in  FIG. 5 , the coil spring  20  is held captive between the scraper head  18  and the substantially rigid member  16 . In this embodiment, the coil spring  20  is not fully decompressed (not in its fully relaxed state). That is, the coil spring  20  would decompress further (to its relaxed state) if the coil spring  20  were not held captive between the scraper head  18  and the substantially rigid member  16 . Thus, the coil spring  20  is exerting a force on the scraper head  18 . Further, in the embodiment shown in  FIG. 5 , the coil spring  20  is not fully compressed. That is, if a force is exerted on the scraper head  18  in direction y, the scraper head  18  will deflect in direction y, thereby further compressing the coil spring  20 . Thus, when a scraper head  18  contacts the inner surface of a tub (not shown), and the scraper head  18  deflects, the scraper head  18  exerts a force on the inner surface of the tub (not shown). 
     In various embodiments, the amount of force that a scraper head  18  exerts on the inner surface of a tub (not shown) can be changed by using a spring with a different spring constant. The deflection also allows the scraper head  18  to maintain contact with the inner surface of a tub (not shown) despite imperfections in the inner surface of the tub (not shown). 
       FIG. 7  is an exploded view of one embodiment of a scraper assembly  8  used in accordance with the present technology. As shown in  FIG. 7 , the scraper assembly  8  includes a substantially rigid member  16 , a pin  22 , a keeper  24 , a coil spring  20  and a scraper head  18 . 
     In the embodiment shown in  FIG. 7 , the substantially rigid member  16  has a hole  26  therethrough. The hole  26  is configured to receive the pin  22 . The hole  26  is preferably circular to receive a cylindrical pin  22 . In various embodiments, the hole can be any shape and the pin can be any corresponding shape. In other embodiments, a substantially rigid member can have a space therein, such as a slot, groove, or other indentation, to receive a pin that does not pass completely through the substantially rigid member. In another example, the substantially rigid member can be solid and the pin can be welded to the surface of the substantially rigid member. 
     In the embodiment shown in  FIG. 7 , the pin  22  is a cylinder with a first end  27  and a second end  28  with a channel  30  therethrough. The first end  27  of the pin  22  is inserted into the hole  26  and attached to the substantially rigid member  16 . The pin  22  is preferably welded to the substantially rigid member  16 . The pin  22  is preferably attached to the substantially rigid member  16  such that the pin  22  is substantially perpendicular to the substantially rigid member  16 . 
     In the embodiment shown in  FIG. 7 , the keeper  24  is a member that fits inside the channel  30 . The keeper  24  preferably fits inside the channel  30  such that the top  32  of the keeper  24  and the top  34  of the pin  22  create a flat surface. The keeper  24  preferably fits inside the channel  30  such that the ends of the keeper  24  protrude beyond the sides of the pin  22 , thereby forming tabs at one end of the pin. The keeper  24  can be attached to the pin  22 . The keeper  24  is preferably attached to the pin  22  by welding. 
     In various embodiments, a pin and keeper can be a unitary member. In such embodiments, the unitary member is a pin with at least one tab protruding from a side of one end of the pin. In various embodiments, the unitary member can be configured such that any number of tabs protrude from a side of one end of the pin. 
     In various embodiments, a substantially rigid member, a pin and a keeper can be a unitary member. In such embodiments, the unitary member is a bar (round or flat) with a pin protruding substantially perpendicular to the length of the bar, and the pin has at least one tab protruding from a side of the end of the pin that is furthest from the bar. In various embodiments, the unitary member can be configured such that any number of tabs protrude from a side of the end of the pin that is furthest from the bar. 
     In various embodiments, a ribbon of an agitator, a substantially rigid member, a pin and a keeper can be a unitary member. In such embodiments, the unitary member is a helically wound ribbon with a bar (round or flat) extending therefrom that has a pin protruding substantially perpendicular to the length of the bar, and the pin has at least one tab protruding from a side of the end of the pin that is furthest from the bar. In various embodiments, the unitary member can be configured such that any number of tabs protrude from a side of the end of the pin that is furthest from the bar. 
     In the embodiment shown in  FIG. 7 , the coil spring  20  can be wound onto the pin  22  by twisting the coil spring  20  around the protruding ends of the keeper  24 , akin to twisting a key onto a key chain. Once the coil spring  20  is wound onto the pin  22 , the coil spring  20  is held captive between the substantially rigid member  16  and the protruding ends of the keeper  24 . The coil spring  20  is preferably made of steel, but can also be made of other materials with steel-like characteristics. In other embodiments, the coil spring  20  can be slid onto the pin  22  prior to attaching the pin  22  to the substantially rigid member  16 . In such an embodiment, once the pin  22  is attached to the substantially rigid member  16 , the coil spring  20  is held captive between the substantially rigid member  16  and the protruding ends of the keeper  24 . 
     In the embodiment shown in  FIG. 7 , the scraper head  18  preferably has two scraping edges  36  that run the length of the scraper head  18 . The scraper head  18  can be configured such that the scraping edges  36  provide scraping in two directions. In various embodiments, the scraper head  18  can have a single scraping edge. In such embodiments, the scraper head  18  can be configured such that the scraping edge provides scraping in one direction. 
     In the embodiment shown in  FIG. 7 , the scraper head  18  has a hole  38  therethrough. The hole  38  is large enough to receive the pin  22 , but not large enough to receive the coil spring  20 . On two sides of the hole  38  (180 degrees apart—around the circumference of the hole  38 ), there are channels  40  that run the depth of the scraper head  18 . On another two sides of the hole  38  (180 degrees apart—around the circumference of the hole  38 ), there are channels  42  that do not run the depth of the scraper head  18 . As shown in  FIG. 7 , the channels  40  that run the depth of the scraper head  18  are 90 degrees apart (around the circumference of the hole  38 ) from the channels  42  that do not run the depth of the scraper head  18 . In various embodiments, channels that run the depth of a scraper head with a hole therethrough need not be 90 degrees apart (around the circumference of the hole therethrough) from channels that do not run the depth of a scraper head. In such embodiments, other degrees of separation are sufficient to allow the scraper head to be attached to the rest of the scraper assembly. 
     In various embodiments, the scraper head can be modified to accommodate any number of tabs protruding from the pin, that is, a corresponding channel that runs the depth of the scraper head and a corresponding channel that does not run the depth of the scraper head can be included in the hole therethrough for each tab. 
     In the embodiment shown in  FIG. 7 , the scraper head  18  is attached to the rest of the scraper assembly by aligning the channels  40  that run the depth of the scraper head  18  with the protruding ends of the keeper  24 . The scraper head  18  is then slid toward the substantially rigid member  16 , thereby compressing the coil spring  20 , until the protruding ends of the keeper  24  pass all the way through the scraper head  18 . The scraper head  18  is then turned 90 degrees such that the channels  42  that do not run the depth of the scraper head  18  are aligned with the protruding ends of the keeper  24 . The scraper head  18  is then allowed to slide away from the substantially rigid member  16 , thereby allowing the coil spring  20  to decompress, until the protruding ends of the keeper  24  contact the end of the channels  42  that do not run the depth of the scraper head  18 . 
     In the embodiment shown in  FIG. 7 , the scraper head  18  is removed from the rest of the scraper assembly by sliding the scraper head  18  toward the substantially rigid member  16 , thereby compressing the coil spring  20 , until the protruding ends of the keeper  24  pass all the way through the scraper head  18 . The scraper head  18  is then turned 90 degrees such that the channels  40  that run the depth of the scraper head  18  are aligned with the protruding ends of the keeper  24 . The scraper head  18  is then allowed to slide away from the substantially rigid member, thereby allowing the coil spring  20  to decompress, until the protruding ends of the keeper  24  are removed from the scraper head  18 . 
     In the embodiment shown in  FIG. 7 , once the scraper head  18  is removed, the coil spring  20  can be removed by winding the coil spring  20  off the pin  22  by twisting the coil spring  20  around the protruding ends of the keeper  24 , akin to twisting a key off of a key chain. 
     In the embodiment shown in  FIG. 7 , once the coil spring  20  and the scraper head  18  are removed from the rest of the scraper assembly, the rest of the scraper assembly can be cleaned and/or a new coil spring and/or scraper head can be attached to the rest of the scraper assembly. 
       FIGS. 8-10  illustrate embodiments of a scraper head  18  used in accordance with the present technology.  FIG. 8  is a perspective view of one embodiment of a scraper head  18 ;  FIG. 9  is a bottom view of one embodiment of a scraper head  18 ; and  FIG. 10  is a top view of one embodiment of a scraper head  18 .  FIGS. 8-10  show aspects of a scraper head  18  that are discussed with regard to  FIG. 7 . For example, the channels  40  that run the depth of the hole  38  are shown in both  FIG. 9  (bottom view) and  FIG. 10  (top view), however, the channels  42  that do not run the depth of the hole  38  are shown in  FIG. 9  (bottom view), but not  FIG. 10  (top view). 
     In the embodiments shown in  FIGS. 8-10 , the scraper head  18  is preferably made of nylon. In various embodiments, scraper heads can be made of other materials, including but not limited to, other types of plastics. One such example is Peek, a commercially available brand of plastic that is manufactured by Victrex plc, a company with manufacturing plants and research facilities in the UK and sales and distributions centers worldwide. Peek, for example, can be used in scraper heads that are utilized in high temperature environments. Scraper heads can also be made of metals, such as steel or other materials with steel-like characteristics, and then coated with plastic, for example. 
       FIG. 11  is a perspective view of one embodiment of agitators  6  and scraper assemblies  8  disposed within a tub  60 .  FIG. 12  is a top view of one embodiment of agitators  6  and scraper assemblies  8  disposed within a tub  60 . In  FIGS. 11 and 12 , two agitators  6  are disposed next to each other within a tub  60 . In other embodiments, any number of agitators can be used depending upon the size of the tub. In the embodiments shown in  FIGS. 11 and 12 , the inner surface of the tub  60  conforms at least in part to the general cylindrical shape of the agitators  6 . This embodiment can be used with the preferred embodiment described above in connection with  FIGS. 2 and 3 . 
     While the above discussion describes the invention with reference to embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.