A peeling machine having series of insert rollers held down into notches between larger-diameter power rollers by holddowns. The holddowns include pins made of a bearing material received directly in bores in the ends of the insert rollers without conventional bearing sleeves. The heads of the pins may be coned to provide thrust bearings against concave interior ends of the bores.

BACKGROUND

The invention relates to peeling apparatus and, more particularly, to roller-type shrimp-peeling machinery.

Originally introduced because of the high labor costs of peeling small shrimp by hand, shrimp-peeling machines are now widely used in the shrimp-processing industry. Roller-type peeling machines, in particular, dominate the bulk shrimp-peeling industry. U.S. Pat. Nos. 2,778,055, Jan. 22, 1957, and 2,537,355, Jan. 9, 1951, both to Fernand S., James M., and Emile M. Lapeyre, describe the basic structure and principles of operation of roller-type shrimp peelers.

In the upper peeling sections of conventional roller-type peelers, a series of small diameter stainless steel insert rollers rest between and on a rubber-coated upper power roller and an adjacent rubber-coated lower power roller vertically and horizontally offset from the upper roller. The insert rollers are rotated by contact with the rubber-coated rollers. Peeling nips are formed between the insert rollers and the lower rollers. The rollers rotate continuously in one direction and then the other to grab and release shrimp urged down the lengths of the rollers by a stream of water and gravity. The insert rollers are held down in the notches between the larger-diameter upper and lower power rollers by holddowns. As shown inFIG. 9, conventional holddowns154include a narrow strap156that fits through the narrow space between the lower and upper rollers and that has a hooked portion158at one end encircling and retaining a cylindrical stainless steel pin160. Springs attached between the peeler frame below and holes162in the straps bias the holddowns into contact against the rubber-coated rollers. The insert rollers164are made of stainless steel and have axial bores166formed in each end. The bores are lined with a bronze bearing sleeve168. The holddown pins are received in the bores. The insert rollers rotate on the pins with the bronze bearing sleeves providing a low-friction bearing surface to the stainless steel pins.

When a conventional insert roller is new, as inFIG. 10A, the holddown pin160rests on the bearing sleeve168in the bottom of the bore of the insert roller164. The contact area between the pin and the sleeve is relatively broad. (In both figures, the diameter of the pin is exaggeratedly small relative to the diameter of the bore for better viewing.) As the bronze bearing sleeve wears, however, as shown inFIG. 10B, the contact area decreases to close to an axial line of contact171along the bottom of the bore166. Furthermore, because the bottom of the bronze bearing has largely worn away, the stainless steel pin160bears directly on the stainless steel bore wall172of the insert roller164. This stainless-on-stainless contact increases friction and can cause galling.

The depth of the bore166in the insert164is greater than the distance of the blunt ends174of the pin from the side175of the hooked portion158of the holddown, as shown inFIG. 9. This makes it possible for the insert rollers164to contact the sides175of the stainless steel hook portion158of the holddowns154. The rotation of the insert on the hooked portion produces an annoying squeaking sound, as well as an increase in friction.

Thus, there is a need for a less noisy peeler with longer lasting insert rollers and holddown pins.

SUMMARY

This need and others are provided by an insert-roller system embodying features of the invention. One version of such a system for a roller-type peeler comprises a holddown and an insert roller. The holddown includes a holder at one end of a shank. A pin is retained in the holder. The insert roller is made of a wear-resistant material, such as stainless steel. A bore at one end of the insert roller is bounded by a bore wall. The holddown pin is received in the bore. The pin is made of a different material from the insert roller and serves as a bearing surface against the bore wall as the insert roller rotates on the pin.

Another version of an insert-roller system for a roller-type peeler comprises a holddown and an insert roller. The holddown includes a holder at one end of a shank. A pin having a coned head at one end is retained in the holder. An axial bore at one end of the insert roller has a concave blind end bearing against the coned head of the pin, which serves as a thrust bearing to prevent contact between the insert roller and the holder.

According to another aspect of the invention, a peeler comprises a plurality of reciprocating upper rollers spaced apart laterally across the width of the peeler. An array of lower rollers underlies the array of upper rollers along a portion of the length of the peeler at positions below and laterally offset from the upper rollers. Series of insert rollers are made of a wear-resistant material. Each series of insert rollers extends along the length of the peeler and rests simultaneously on one of the upper rollers and one of the adjacent lower rollers. Each of the insert rollers has opposite ends with an axial bore in each end. Holddowns each have a holder retaining a pin at an upper end. A shank portion extends downward from the holder through a gap between one of the upper rollers and an adjacent one of the lower rollers. The shank is biased downward. The pins are made of a material different from the wear-resistant material of the insert rollers. The pins are received in the axial bores of the insert rollers, which rotate on the pins.

DETAILED DESCRIPTION

An exemplary version of a peeling apparatus embodying features of the invention is shown inFIGS. 1 and 2. The peeling apparatus20, which is typically used to peel shrimp, includes a frame22consisting of front and rear legs23,24forming a framework with various cross-bracing and support members. A bed26supports peeling rollers that slope downward from a first product-entrance end27to a second product-exit end28. (To simplify the drawing, a finger frame, typically used to urge shrimp into peeling positions, is not shown.) The rollers shown inFIG. 1include two kinds of powered rollers: upper channel-forming rollers30and lower power rollers32. In an upper peeling portion of the peeling apparatus, a plurality of side-by-side peeling channels are formed by a lower power roller32flanked by two upper channel-forming rollers30. All three rollers forming each upper channel are powered directly by the peeling apparatus's drive system. Each of these rollers is made of a tube, typically steel, coated with a coating such as a rubber-like material to form an outer peeling surface. The coating could be a polyurethane, as well as other synthetic or natural materials, to provide the peeling effectiveness or durability required by the application. The coating could be left off and the uncoated tube constructed entirely of stainless steel, for instance, with or without a knurled, sandblasted, or otherwise textured surface. The upper peeling channels are further formed by narrow-diameter insert rollers38held down into the notches between the power rollers. The insert rollers rotate by contact with the power rollers, which are driven alternately clockwise and counterclockwise by the drive system. The insert rollers are typically made of stainless steel with or without surface texturing. The insert rollers are encircled at various positions along the channel by holddowns40. The holddowns, which are attached to the frame22, are tensioned by springs41, for example, to pull the insert rollers38down into the notches to form peeling nips43with the lower rollers. Rods45are each threaded at a bottom end with a wing nut49compressing the spring41surrounding the rod against the frame22. Hooks51at the end of the rod hook into holes in the holddowns40. The spring pressure is adjusted with the wing nut49.

A lower peeling portion of the peeling apparatus is formed by the lower power rollers32supported on lower idle rollers42. Unlike the power rollers32and the channel-forming rollers30, the lower idle rollers42are passive and rotate only by frictional contact with the power rollers. Like the power rollers, the lower idle rollers are tubes preferably coated with a rubber-like material. The channel-forming power rollers30and the insert rollers38do not extend down into this lower peeling portion of the apparatus. The peeling nip formed in the lower peeling section produces a peeling action different from that in the upper peeling section. Subjecting product to be peeled, such as shrimp, to both kinds of peeling action produces a more effectively peeled product.

Both the upper channel-forming rollers30and the lower power rollers32are powered at the upper end of the peeling apparatus. A drive system comprising, for example, a rack gear44linked to a crank and a pitman arm driven by a motor (not shown) is used to reciprocate the rack gear. A drive member46, including a toothed gear wheel47connected at a first end of each of the powered roller assemblies, meshes with the rack gear. As the rack gear reciprocates, the powered roller assemblies rotate clockwise and counterclockwise in synchrony with the rack. Idler wheels48, in rolling contact with the upper surface of the rack, retain it in position. A cover plate50at the first upper end of the powered roller assemblies may be used to separate the drive system from the peeling channels. Openings52formed in the plate admit the drive member portion of the powered roller assemblies into an engagement position with the drive system of the peeling apparatus.

An interior holddown54used between consecutive insert rollers is shown inFIGS. 3 and 4. The holddown54is shown as a narrow strap having a shank56and a hook-like holder58at the top end of the shank. The strap is made of a durable, wear-resistant material, such as stainless steel. A pin60is retained in the holder58by a press fit, for example. The pin is knurled62for better retention in the holder. The pin60in the interior holddown54extends outward in opposite directions from the holder and terminates in coned heads64at each end. A hole66in the bottom end of the strap engages the hooks51on the threaded rod45, as shown inFIG. 2. The pin is made of a bearing material different from the strap material. Bronze is one example of the bearing material for the pin.

FIG. 5shows an outer holddown68that engages the outer ends of the first and last insert rollers in an insert-roller series. The outer holddowns have a lower shank70that differs in shape from the shank of the interior holddowns54. The difference is for conforming to the structure of the peeler at the upper and lower ends of the upper peeling channels and to direct the line of force biasing the holddown into the end of the insert roller with an axial, as well as a radial, component. The outer holddowns68have a holder72for a one-sided pin74terminating in a single coned head76. The pin74is made of a bearing material, such as bronze, and the holder and shank are made of a harder, wear-resistant material, such as stainless steel.

As shown inFIG. 6, each insert-roller section78is made up of a series of insert rollers38that rotate on the pins of holddowns—outer holddown68at the two ends of the series of inserts and interior holddowns54between consecutive insert rollers.

As shown inFIG. 7, the opposite coned heads64of an interior holddown54bear against concave blind ends80of axial bores82in the ends of each insert roller38. The blind ends80are, for example, complementary conical end walls of bore walls84bounding and defining the bores82. The distance86from the holder58to the tip end of the pin's coned head64is preferably greater than the length88of the axial bore82in the insert roller38so that the end face90of the insert roller doesn't bear against the holder58. Thus, the conical head64of the pin64serves as a thrust bearing against the insert roller38. As an alternative, ball bearings89pressed or otherwise deposited in the bores82between the interior end walls80and the ends of the pins60, which can be flat as inFIG. 9, rather than coned, can serve as thrust bearings between the insert rollers38and the holddowns54to reduce noise.

As shown inFIGS. 8A and 8B, the insert roller38does not require a bearing sleeve168as in the prior art insert164ofFIGS. 10A and 10B. For this reason, the bore82in the improved insert roller38can be small in diameter, which allows for a greater bore wall thickness92resistant to flaring. When the holddown pin60is new, it is cylindrical, as inFIG. 8A. As the pin60′ wears, as shown inFIG. 8B, its softer material conforms to the shape of the bore and provides a large bearing contact area94with the bore walls84. And only the holddown is replaced instead removing and reinstalling bearing sleeves in the insert rollers. (In both figures, the diameter of the pin is exaggeratedly small relative to the diameter of the bore for better viewing.)