EP0071298B1

EP0071298B1 - Sharpening unit principally for foodstuff slicing machines

Info

Publication number: EP0071298B1
Application number: EP82200915A
Authority: EP
Inventors: I.R. R.T. Escher
Original assignee: Maatschappij Van Berkels Patent BV
Current assignee: Maatschappij Van Berkels Patent BV
Priority date: 1981-07-31
Filing date: 1982-07-19
Publication date: 1986-01-22
Also published as: IT8123321A0; EP0071298A1; DE3268661D1; IT1137776B

Description

The present invention relates to' a sharpening unit which can be applied principally to slicing machines operating with a rotating circular cutter-knife and used for slicing foodstuff products.
Various kinds of said slicing machines are known: those driven manually or electrically, those with vertical or inclined cutter-knife and, in the versions used in the trade they are always provided with a sharpening unit for sharpening the cutter-knife blade if this is not sharp enough to slice the foodstuff product. Said sharpening unit is incorporated in the slicing machine or separated from it; in this latter case, however, it is separated in such a way as to be able to be connected to one of the component parts of the slicing machine.
GB-A-525 920 and GB-A-532 298 disclose a slicing machine with incorporated sharpening unit comprising a pivot fixed to the slicing machine, on which pivot there is articulated a support structure for two wheels rotatably carried thereby. The unit also comprises a lever element adapted to actuate the unit according to a preestablished sequence to cause the wheels to come to bear against the blade of the circular cutting-knife. The support structure for the wheels is closed on its upper side by a blade-protection cover. One of the wheels, for sharpening, is used to remove material from the worn blade, while the other, flash-cleaning wheel is used to remove the flash formed on the blade by the former grinding or sharpening wheel. The wheels are commonly arranged at opposite sides of the rotary cutting-knife. The flash-cleaning wheel may be replaced by a wheel made of hardened material.
These incorporated types of sharpening units have the drawback that it is difficult to reach the corners and the small space between the component parts for cleaning the sharpening unit, and so its cleanliness and appearance are thus neglected. The wheels, furthermore, become impregnated with fatty substances or other foodstuff residues, which require to be removed for reasons of hygiene and to restore efficiency to the wheels themselves. For this reason said wheels have periodically to be dismantled from the support structure and immersed in a special solvent liquid.
Dismantling the said wheels is, however, a troublesome operation calling for special tools; in some cases the units themselves have to be dismantled from the slicing machine and immersed wholesale in the solvent liquid for their grinding and flash-cleaning wheels to be cleaned.
Furthermore, the incorporated types of sharpening units have to be lifted, rotated through an angle ranging from 45° to 180°, depending on the model, and, finally, have to be pressed downwards before they can be brought into operating position.
These operations are troublesome for the user of the slicing machine above all because they are complex operations.
It is also to be added that GB-A-525 920 discloses a safety means which prevents actuation of the motor operating the rotary cutter blade when a cover part for the blade is removed. These means comprise a microswitch operated by a train of balls arranged within a guide. The balls are compressed in the guide to close the microswitch for operating the motor when the cover parts are in the covering position, while when one of said cover parts is removed the balls are uncompressed in the guide and the microswitch opens the motor actuating circuit.
US-A-2 030 197 discloses a slicing machine having a sharpening unit comprising a sharpening wheel and a burnishing wheel each rotatably arranged on a respective pivotable arm. The wheels are moved into operative and inoperative position by a knob which is either pushed or pulled to operate the respective wheel arm. The wheels and the arms are arranged within a casing which can be opened by removal of a frontal guard plate which also covers most of the slicing cutter blade. Removal of the frontal guard plate allows cleaning of the sharpening and burnishing wheels without particular difficulty.
The conventional sharpening units of separate type differ from those of the incorporated type in that the support structure, and thus all that is connected to it (grinding and flash-removal wheels, lever element, etc.), has to be mounted on the slicing machine proximally to the cutter-knife blade before sharpening can be commenced, and has to be removed from the slicing machine when sharpening is concluded. This often means removing a number of component parts of said machine for the mounting to be possible which is troublesome for the user of the slicing machine above all because it is a complex operation. This mounting furthermore requires the shifting of the faceplate and other parts of the slicing machine which normally protect the cutter-blade from accidental contacts caused by the operator. This is very dangerous, and in certain countries with severe safety regulations it is prohibited to market such machines featuring such type of sharpening unit.
The object of the present invention is to obviate the said problems caused by the existing sharpening units, by providing a sharpening unit particularly for foodstuff slicing machines which is easy to operate and to clean and which is capable of satisfying severe safety regulations.
This object is attained by a sharpening unit for slicing machines according to claim 1.
For a clearer understanding of the characteristics and advantages of the present invention, there is given below a description of one exemplifying and not limiting embodiment thereof, illustrated in the attached drawings in which:

FIGURE 1 is a perspective view of a sharpening unit according to the invention applied to a slicing machine operating with a rotating circular cutter-knife,
FIGURE 2 is a section of the sharpening unit of FIGURE 1 along the line II-II of FIGURE 3,
FIGURE 3 is a partially sectional view of the sharpening unit of FIGURE 1 in the direction of the arrow F of FIGURE 4,
FIGURE 4 is a sectional view of the sharpening unit of FIGURE 1 along the line IV-IV of FIGURE 3,
FIGURE 5 is a sectional view of the sharpening unit of FIGURE 1 along the line V-V of FIGURE 3.

In FIGURE 1 there is indicated by 10 a sharpening unit according to the invention mounted on a slicing machine 11 fitted with a rotating circular cutter-knife 12.
The unit 10 comprises a boxlike shield 13 rotatably and removably mounted to a fixed structure 14 of the slicing machine 11 in a position such as to overhang the cutter-knife 12 and to allow the blade 15 of the cutter-knife 12 to move within it.
The boxlike shield 13 has within and solid with it a bushing 16 which fits over a small vertical column 17 mounted rotatably on the fixed structure 14. The mounting of this column is effected by engaging a cylindrical lower end portion 32 of the column 17 with a corresponding seating 33 of the fixed structure 14 (FIGURE 3). The bushing 16 is adapted to be rotationally fixed to the column 17 by a dowel 26 which crosses the bushing 16 transversally and fits into a longitudinal groove 27 of the column 17 which runs to the upper end of said column 17 (FIGURE 2). The bushing 16 can in this way slide longitudinally on the column 17 to the point of coming off it, but cannot rotate with respect to it.
Inside the boxlike shield 13 there is removably mounted a block 18 which supports a first sharpening tool in form of a grinding wheel 19 in a freely rotatable manner. Two vertical pegs 20 and 21 solid with the wall 30 of the head of the boxlike shield 13 are provided for the mounting of the block 18. These pegs insert themselves respectively into a corresponding through-hole 22 and a corresponding dead hole 23, both formed in the block 18. The free end of the peg 20 projects from the lower side of the block 18 when this has been mounted (FIGURE 4) and carries a groove on its circumference to receive the claws of a small spring 24 secured to the block 18 at 25 and adapted to retain the block 18 against the boxlike shield 13 (FIGURE 2). The grinding wheel 19 is proximal to the blade 15 and is adapted to sharpen it.
Within the boxlike shield 13 there is also mounted in a removable manner a second, flash-removing tool in form of a small circular plate 28 made of hardened steel, disposed proximally to the blade 15 from the side opposed to the grinding wheel 19 and downstream of it (FIGURE 4). The small plate 28 has a central hole to allow it to be placed over a T-pin 29 solid with a lateral wall 31 of the boxlike shield 13 and then restrained, with a downward movement, between the head of the pin 29 and the wall 31 (FIGURE 5).
Finally, inside the boxlike shield 13 there is provided a projection 34 of a lateral wall 35 of the boxlike shield. To this projection is screwed a pin 36, transversal to the blade 15, which pin slides in a corresponding through-seating 37 of a small block 38 against a spring 39 wound about the pin 36. At one of its ends, the spring 39 is fixed in the seating 37, while the other end is fixed to the projection 34. In the block 38 there is also formed a seating 48 for a vertical pin 40 locked to the fixed structure 14. This is clearly shown in FIGURE 5.
For reasons to be explained hereinafter, the small column 17 has within it a longitudinal cavity 41 which houses in slideable manner a small rod 42, which extends to the interior of the fixed structure 14through a guide hole 47 in the seating 33. The small rod 42 is thrust downwards, when the bushing is fitted over the small column 17, by a longitudinal pin 43 screwed into the bushing 16. The pin 43 presses on the upper end of the small rod 42 which with its lower end flexes downwards a small elastic lamina 44 restrained to a microswitch 46 fitted inside the fixed structure 14. The small lamina 44, in turn, in its flexing movement, presses a pushbutton 45 of the microswitch 46. This is clearly shown in FIGURE 3. The pin 43, the small rod 42, the lamina 44, the pushbutton 45 and the microswitch define pilot means for stopping the actuation of the cutter-knife 12.
The microswitch 46 forms part of an electrical safety circuit on the slicing machine: when the pushbutton 45 is depressed, the supply circuit of the drive group for the cutter-knife 12 is energized, and the said cutter-knife can be set in operation through a central switch controlled by the operator. When the pushbutton 45 is released, the supply circuit is deenergized and the drive group cannot in any way be started up.
For the sake of simplicity, the safety circuit, the supply circuit, the drive unit and the central switch, which can be variously embodied by any person skilled in the art, are not illustrated.
To mount the boxltke shield 13 on the fixed structure 14 it is sufficient to slip the bushing 16 onto the small column 17, sliding the dowel 26 in the grooving 27, and to fit the block 38 onto the pin 40. When mounted in this way, the boxlike shield 13 can oscillate around the seating 33 against the spring 39.
To sharpen the blade 15, the operator has to actuate the cutter-knife 12 and then bring pressure to bear in the direction of the arrow A (shown in FIGURES 1 and 5); in this way the grinding wheel 19 touches the blade 15 and can perform its known abrasive action on the blade.
When sharpening is complete, to remove the flash that has formed from the blade 15, the operator has then to release the boxlike shield 13, which returns to the rest position of FIGURE 4, through the action of the spring 39; the operator has then again to bring pressure to bear on the boxlike shield 13 in the direction opposed to the aforesaid direction and that is to say in the direction of the arrow B (shown by a dashed and dotted line in FIGURE 1, and also shown in Figure 5). This causes the small plate 28 to touch the blade 15 and remove the flash in known manner. Once flash-removal has been completed, when the boxlike shield 13 is again released, it returns, once more by effect of the action of the spring 39, to the rest position of FIGURE 4, and the cutter-knife is ready to be used for slicing.
The sharpening unit 10 described above offers various advantages.
Firstly it can be actuated by two very simple press-operations by the operator, as seen heretofore.
Secondly, it is easy to remove to allow cleaning operations, it being necessary only to raise the boxlike shield 13. Its parts have the same ready ease of dismantling: to free the block 18 from the boxlike shield 13 it in fact suffices to free the pin 20 from the grip of the spring 24. In this way, by means of operations which are all rapid, the grinding wheel 19 carried by the block 18 can be cleaned or substituted. Similarly, to clean or substitute the small plate 28, it is only necessary to raise it and remove it from the pin 29.
Finally, the said sharpening unit 10 satisfies the severest safety regulations. For, when it is mounted on the machine it covers the portion of the blade 15 comprised between the blade-cover, not shown in the FIGURE, and the faceplate 49, thus preventing the blade 15 from being touched accidentally. When the boxlike shield 13 is removed, the small rod 42 is freed by the pressure exerted by the pin 43 and, as a consequence, the small lamina 44 rises and releases the pushbutton 45, and, as described previously, prevents the cutter-knife 12 from being actuated.
Clearly, the present exemplifying embodiment does not place restrictions on possible variants and/or additions that fall within the scope of the claims.
In particular, the shape of the boxlike shield 13 and its type of mounting on the slicing machine 11 can be of numberless kinds as dictated by the imagination of the person skilled in the art. The same applies in respect of the other parts of the sharpening unit 10.

Claims

1. A sharpening unit (10) for slicing machines (11) which operate with a rotating circular cutter-knife (12), said unit (10) comprising an element (13) for shielding and protecting the blade (15) of said cutter-knife (12), the element (13) being rotatably and removably mounted to a fixed structure (14) of said slicing machine (11) adjacent said blade (15), within the said shielding and protective element (13) there being removably fitted thereto means (19, 20) for sharpening said blade, said means consisting of a first, sharpening tool (19) and a second flash-removing tool (28) disposed on opposed sides with respect to said blade (15) and adjacent thereto, the said shielding and protective element (13) being rotatable against the bias of elastic means (39) between a position in which said first, sharpening tool (19) is in contact with said blade (15) and a position in which said second, flash-removing tool (28) is in contact with said blade (15) and being adapted, at the time of its removal from the slicing machine (11), to cooperate with pilot means (44-46) for stopping the actuation of the cutter-knife (12).

2. A sharpening unit (10) according to claim 1, characterized by the fact that said first tool consists of a circular grinding wheel (19) pivoted to said shielding and protective element (13).

3. A sharpening unit (10) according to claim 1, characterized by the fact that said second tool consists of a small plate (28) made of hardened material which has a central hole for fitting it in restrained manner on a T-pin (29) solid with said shielding and protective element (13).

4. A sharpening unit (10) according to claim 1, characterized by the fact that said shielding and protective element (13) features a pin (43) adapted to actuate, by means of a rod (42) sliding in a guide (47) of said fixed structure (14), a switch-member (44, 45, 46) so as to pilot it to energize the electrical supply circuit of a drive unit for said cutter-knife (12) when said shielding and protective element (13) is mounted on said slicing machine (11), and to de-energize said supply when said shielding and protective element (13) is removed from said slicing machine (11).