US3789632A

US3789632A - Automatic thickness regulator for skin-shaving machines

Info

Publication number: US3789632A
Application number: US00292095A
Authority: US
Inventors: S Repetto
Original assignee: Luigi Rizzi and Co SpA
Current assignee: Luigi Rizzi and Co SpA
Priority date: 1971-12-15
Filing date: 1972-09-25
Publication date: 1974-02-05
Anticipated expiration: 1991-02-05
Also published as: JPS4867404A; FR2165377A5; GB1355469A; CS161810B2; DE2246733A1; IT943995B; ES406392A1

Abstract

In a skin shaving machine, a mechanism is provided for automatically regulating the thickness of the skin being processed. A shaped surface of a governing piston, shaped so as to present zones of different surface area cooperates with a feeler. The surface area variation of the core keeps into account the thickness trend of the several portions of a skin, viz. head, neck, trunk, hindquarters. By the mechanism so provided a perfectly even thickness of the shaved skin is automatically obtained without requiring the intervention of an operator, the latter being enabled to attend to other machine operations.

Description

[ 1 Feb.5,i974

United States Patent [1 1 Repetto 69/42 10/1969 Great FOREIGN PATENTS OR APPLICATIONS 1,167,223 10/1969 Great Britain....... 7 1,168,733

AUTOMATIC THICKNESS REGULATOR FOR SKIN-SHAVING MACHINES [75] Inventor: Silvio Repetto, Modena, Italy [73] Assignee: S.p.A. Luigi Rizzi & C.

M d 0 cm Primary Examiner-Alfred R. Guest Italy Attorney, Agent, or FirmChar1es E. Brown et a1.

[22] Filed: Sept. 25, 1972 [211 Appl. No.: 292,095

[ ABSTRACT In a skin shaving machine, a mechanism is provided for automatically regulating the thickness of the skin Foreign Application Priority Data Dec. 15, 1971 being processed. A shaped surface of a governing piston, shaped so as to present zones of different surface area cooperates with a feeler. The surface area varia- 69/42 tion of the core keeps into account the thickness trend Cl4b 17/00 d 69/10 42 of the several portions of a Skln, V1Z. hea neck, trunk, hmdquarters. By the mechanism so provided a perfectly even thickness of the shaved skin is automatically obtained without requiring the intervention of an operator, the latter being enabled to attend to other machine operations.

S mmm T mm N m WMMCS mns wmw mm m nrT m mm& H NW N I l U rm k UI F H N/M wwww 10 Claims, 3 Drawing Figures 3,041,865 7/1962 Gianoglio..................... 3,083,559 4/1963 Eberhardt....... 3,276,230

AUTOMATIC THICKNESS REGULATOR FOR SKIN-SHAVING MACHINES This invention relates to an automatic thickness regulator for skin-shaving machines.

It is known that skin-shaving machines generally comprise two rollers, between which the skins to be shaved are caused to pass. A first roller, hereinafter called pressure roller is usually made of smooth steel and is rotated at a low speed, whereas the second roller, which will be called shaving drum hereinafter, carries on its peripheral surface two sets of blades which are arranged along right and left-handed spirals which converge towards the midpoint of the drum, the latter being rotated at a high speed.

The presence ofsuch helical blades causes the skin, as it to be passed between the roller and the drum, is stretched parallely to the axes of the roller and the drum until being reduced to thinner thickness which is as even as practicible. The portion in excess of the distance between the generating lines of the roller and the drum is removed by the blades of the shaving drum.

Should any skin be of constant width and appearance its entire length throughout, upon completion of the shaving stage and after the subsequent resilient restoration of the skin to a greater thickness, a skin of positively constant thickness could be obtained, that which would be an ideal condition in order to satisfy the customers requirements. In the actual practice, however, it occurs that a skin, while having both a width and aspect which are virtually uniform throughout the entire trunk portion of the animal, exhibits considerable variations in correspondence with the neck and head areas on the one hand, and of the hindquarter region on the other hand.

More particularly, it occurs that in the neck and head region the skin has features which are sharply different (a reduced elasticity) with respect to the trunk area and that, in correspondence with the head, also the width is considerably reduced. These facts involve, on the one hand, a lesser return of the skin (in those regions) to a greater thickness upon shaving, and, on the other hand, since the stretching force imparted by the blades to the areas of reduced width is obviously lesser, the result is a less pronounced thickness reduction prior to shaving and thus a greater amount of shaven out material. The consequence is, in the areas indicated above, a final thickness of the skin undesirably reduced as compared with that of the trunk region.

The same drawback, or nearly so, is experienced in correspondence with the hindquarter region, where the width difference with respect to the trunk are mainly responsible for causing the undesirable reduction of the final. thickness The shaving problem for the neck and head regions has been solved by a number of manufacturers by means of a device which, as controlled by an operator, gradually increases the nip between the roller and the drum during progress of the shaving operation in those areas (usually the last to be engaged by such an operation), so as to allow for both the different elasticity and the different width (more or less gradually decreasing) of the skin.

The shaving problem of the hindquarter region, conversely, is still unsolved, since the provision of a duplicate similar device as controlled by an operator would render the manipulation by the operator exceedingly clumsy, the consequence being a possibility of errors and omissions.

An object of the present invention is thus to provide a device which is capable of automatically varying the nip between the roller and the drum during shaving of the hindquarter regions of a skin and of automatically restoring the nip to the normal magnitude again as the shaving of the trunk area is being started.

In view of this object, the device according to the invention has now been devised, which is characterized in that it comprises a slidable piston which is responsive to the closing of the machine for starting the shaving of a skin so as to be gradually shifted from a first position where a feeler engages the initial area of a shaped region, to a second position where the feeler engages the final portion of said shaped surface, the feeler being operatively connected either to the roller or the drum so as to cause them gradually to approach as a result of the shift of the feelers engagement from the initial portion to the final portion of the shaped surface of said core.

It is apparent that by so doing the leading end of the skin, which is the one having the lesser width, finds the roller and the drum at such a nip as to allow for the stretching force imparted to the skin and then, as the skin width is gradually increasing, the nip is decreased automatically until reaching a minimum magnitude which, obviously, will be caused to coincide with the one which is desired for shaving the trunk area. The result is thus a skin which has been perfectly shaved to the desired thickness also in the hindquarter area, this being obtained without any intervention of an operator.

The features of the present invention will become more clearly apparent upon a scrutiny of the ensuing detailed description of a preferred embodiment thereof as shown in the accompanying drawings, wherein:

FIG. 1 shows a skin shaving machine incorporating a thickness regulator according to this invention.

FIG. 2 is a plan view showing a so-called calfs halfskin."

FIG. 3 is a longitudinal cross-section view showing the way in which the thickness of the half skin of FIG. 2 is varied when passing through a shaving machine.

The machine shown in FIG. 1 comprises, in the first place, a smooth pressure roller 1 and a shaving drum 2 equipped with a number of shaving blades 3, the latter being arranged along two sets of right and left helixes which converge in the mid region of the drum.

The pressure roller 1 is supported for rotation by a supporting member 4 journalled at 5 to the fixed frame (not shown) of the machine. The control of the shifts of the supporting member 4 is entrusted to a connecting rod 6 which is 'eccentrically mounted on a shaft 7. To the shaft is'also keyed a pinion 8 which is in mesh with a rack portion of a piston 9 sliding within a cylinder 10. The end spaces of the cylinder 10 can be alternatingly connected to a duct 11 for feeding oil under pressure, or, as an alternative, to a dump pipe consistently with the angular position of the movable core of a valve 12, the latter being controlled by an operator through a control 13.

The pressure roller 1 is maintained in engagement with a motor-driven roller 14, the latter being supported by a lever 15, pivoted at 16. A spring 17 has the task of ensuring that the engagement between the two rollers 1 and 14 be maintained.

The shaving drum 2, which is rotated at a high speed by a prime mover unit not shown in the drawing, is supported for rotation, in turn, by a supprting member 18, which is fulcrumed at 19 and rests against the jutting stem 20 of a piston 21 of a hydraulic jack 22. The position of the piston 21 is controlled at every instant of time by a valve 23, whose task is to govern the connection of a duct 24 for oil under pressure, and of a discharge duct 25, with two ducts, 26 and 27, which are connected to the upper chamber and the lower chamber, respectively, of the hydraulic jack 22.

The valve 23, more particularly, comprises a valve body 28, which can be axially shifted but cannot be rotated, and in whose interior there is arranged a slidable spool 29, the latter having a stem 30 and two

pistons

31 and 32, a spring 33 biassing the assembly. From the body valve 28, projects a stem 34, coaxially with which there is mounted, so as to be allowed to be rotated only with respect to the valve body 28, an externally screwthreaded sleeve 35 having affixed to its end a handwheel 36. The sleeve 35 engages a nut 37 which is connected with a fixex supporting member 38 so as to be rotated only about its own axis. A manipulation lever 39 is mounted on the nut 37.

The end ofthe stem 30 which projects outwards from the valve body 28 engages one end of an axially slidable feeler 40, whose opposite end is kept engaged by a spring 41 against the frustoconical surface of a slidable piston 42, the latter having the bottom surface with an area greater than that of the top surface. The piston 42 is housed in a cylinder 43 (integral with the supporting member 18), whose bottom chamber is connected to the uppermost chamber of the cylinder 10 by means of a duct 44, and the top chamber being connected to the feeding duct 11 by means of a duct 45 having therein an adjustable throttling valve 46.

in operation, when it is desired to introduce the skin, for example the half skin 47 of FIG. 2 between the roller 1 and the drum 2 to start a shaving stage, the control 13 is manipulated at the outset so as to bring the movable spool of the valve 12 to the position which connects the bottom chamber of the cylinder 10 with the feeding duct 11 and the top compartment of the cylinder 10 with the outlet. As a result, the piston 9 is raised, so as to cause, by means of the pinion 8, a rotation of the shaft 7: the latter causes, through the connecting rod 6, the rotation in the clockwise direction of the supporting member 4, to shift the pressure roller 1 away of the shaving drum 2. Thus the open machine position is reached.

The connection brought about by the valve 12 between the top chamber of the cylinder 10 and the outlet involves, at the same time, the connection of the bottom chamber of the cylinder 43 to the outlet, so that the piston 42, as urged by the pressure in the top chamber of the cylinder 43, is shifted downwards to the position defined by its abutment against a set screw 48. Consequently, by overcoming the bias of the spring 41, the feeler is shifted towards the right (as viewed in FIG. 1) and this causes a like shift of the spool 29 in the interior of the valve body 28 (whose position is set by the handwheel 36). Then the piston 32 opens the communication between the feeding duct 24 and the duct 26, so that the piston 21 is urged to fall and the result is the anticlockwise rotation of the supporting member 18 of the shaving drum 2. Such an anticlockwise rotation obviously involves a return downwards the left of the fixed body which contains the feeler 40 and thus also of the feeler itself, so that also the slidable body 29 is again shifted towards the left until cutting with the piston 32 the previously established communication between the

ducts

24 and 26. An equilibrium condition is thus obtained, to which there corresponds a farther position of the shaving drum 2 relative to the pressure roller 1. Consequently, once a skin has been introduced between the roller 1 and the drum 2 (starting from the hindquarter region 49) and once the valve 12 has been brought back to the position of FIG. 1, to which correspond the return of the piston 9 and the roller 1 to the closed machine" position of FIG. 1, the skin is engaged between a roller and a drum which are set at a distance which is greater than that which would have otherwise been determined with the handwheel 36, and, exactly, at such a distance as to allow for the thicker thickness of the skin in the hindquarter region (FIG. 3) which is determined by the reduced stretching force imparted by the blades 3 to that skin area. The value of the thickness incease is adjustable with the screw 48.

The restoration of the valve 12 to the conditions of FIG. 1, however, has involved a renewed connection of the duct 44 with the feeding duct 11. The result is that, due to the different areas of the two end surfaces of the piston 42, the latter is slowly shifted upwards at a speed which is governed by the setting of the throttle valve 46. The shaped surface of the piston 42 then causes a gradual left shift of the feeler 40, so that the shaving drum 2 gradually approaches to the pressure roller 1 up to a minimum distance which is defined by the initial setting made by the handwheel 36 and which corresponds to the thickness that is desired for the trunk region 50 of the half skin 47. Obviously, the gradual movement of the shaving drum towards the pressure roller can have a basic regulation through the determination of an appropriate shape of the piston 42 and a further adjustment of the valve 46, whereas the magnitude of the initial gap can be adjusted by the screw 48, the whole in such a way as to adapt the gap differentials between the roller and the drum to the trend of skin thickness in the hindquarter area, the final object being to obtain, on completion of the shaving stage, an extremely satisfactory thickness evenness between the hindquarter and the trunk region of the skin.

The regulation of the thickness in the trunk region 51 and the head area 52 is carried out, conversely, in a conventional way by means of the lever 39, whose rotations cause the axial shift of the sleeve 35 and the valve body 28, the result being a gradual movement of the shaving drum 2 farther and farther away of the pressure roller.

What I claim is:

1. In a skin shaving machine of the type including cooperating first and second rollers between which a skin is fed to effect shaving thereof, said rollers including a shaving roller and a pressure roller, means mounting said first roller between an open position for the reception of a skin between said rollers and a closed position wherein said rollers are operative to shave a skin, first control means for selectively positioning said first roller in one of said closed and open positions, means mounting said second roller for movement toward and away from said first roller, second control means for effecting movement and positioning of said second roller; an automatic thickness regulating device operatively connected to said second control means for actuating said second control means for effecting the gradual movement of said second roller towards said first roller during an initial portion of a skin shaving operation, said automatic thickness regulating device including a movable control member coupled to said first control means for movement in response to actuation of said first control means to move said first roller to said closed position.

2. A regulating device according to claim 1 wherein said control member has a shaped surface, and means coupling said control member to said second control means includes a feeler riding on said shaped surface.

3. A regulating device according to claim 2 wherein said second control means includes a control valve, and said feeler is coupled to said control valve for positioning the same.

4. A regulating device according to claim 3 wherein said second control means includes a piston for positioning said second roller, and said control valve is coupled to said piston for controlling the flow of fluid thereto.

5. A regulating device according to claim 2, characterized in that said shaped surface is in the shape of a cone.

6. An adjusting device according to claim 2, characterized in that said control member and said feeler are housed in bodies which are mounted on a supporting member for the shaving roller, said second control means includes a double faced piston for positioning said shaving roller and a control valve for controlling the flow of a control fluid to said piston faces, and said feeler is in engagement with said control valve for adjusting the pressure acting on the two faces of said pis ton.

7. A regulating device according to claim 1 wherein said control member is a double acting piston, and said first control means includes valve means for selecting varying fluid pressures acting on said piston.

8. A regulating device according to claim 1, characterized in that said control member is a piston with end surfaces having different areas and is slidably housed in a hollow body which is partitioned into two chambers by said control member, the chamber confined by the end surface of said control member having the lesser surface area being constantly connected with a source of pressurized fluid, the chamber confined by the portion of said control member having the greater surface area being alternately connected to a discharge and to a source of pressurized fluid by said first control means as a function of the open machine condition and the closed machine condition, respectively, of said first roller.

9. An adjusting device according to claim 8, characterized in that there is a duct which connects said chamber confined by the end surface of said control member having the lesser surface area with the relative source of pressurized fluid, and an adjustable throttling valve is incorporated in said duct for controlling the rate of movement of said control member.

10. An adjusting device according to claim 8, characterized in that there is an adjustable stop for defining a first position of the movable control member.

Claims

6. An adjusting device according to claim 2, characterized in that said control member and said feeler are housed in bodies which are mounted on a supporting member for the shaving roller, said second control means includes a double faced piston for positioning said shaving roller and a control valve for controlling the flow of a control fluid to said piston faces, and said feeler is in engagement with said control valve for adjusting the pressure acting on the two faces of said piston.