Food slicer

Abstract: A food slicer comprises: an end detecting means (20) for detecting end portions of a food H fed by a feeding means (10); a retaining member (67) arranged movable with the food H in a feeding direction of the feeding means (10) and retractable at substantially a right angle to the feeding direction for penetrate into and departing from the food H; and a controlling means responsive to a detection signal of the end detecting means (20) for causing the retaining member (67) to penetrate into and hold the other end of the food H, and travel with the food H until the other end of the food H comes close to a rotary knife (31).

Description: BACKGROUND OF THE INVENTION The present invention relates to a food slicer for slicing lumps of food, such as ham, sausage, or cheese. Among such food slicers is a ham slicer which generally comprises a feeding means including pair of belt conveyors arranged opposite to each other for holding and feeding downwardly a loaf of ham therebetween, and a cutting means for cutting with a rotary knife the loaf of ham fed from the feeding means into slices from its leading end. Also, a conventional ham slicer of another type is available having a gripper for holding and feeding the trailing end of a loaf of ham in a given direction. In action, the gripper has to repeat a gripping action to hold a succeeding loaf of ham during an interval between cutting of the current ham and cutting of the succeeding ham. This interval between the cutting actions interrupts a continuous procedure and will thus decrease the efficiency of production. On the other hand, the ham slicer with the belt conveyor type feeding means allows loafs of ham to be sliced continuously. As the belt conveyor feeding type ham slicer is higher in the efficiency of production, it is more widely be used. However, the ham slicer with the belt conveyor type feeding means has a disadvantage. The loaf of ham is stably held between the two belt conveyors when its main central portion which is substantially uniform in the diameter remains lengthy. The holding of the loaf of ham will be unstable as the length of the central portion of the ham is decreased during the cutting. Accordingly, as a trailing portion of the ham which diameter is smaller than that of the central portion comes close to the cutting means, the holding strength of the two belt conveyers is lessened. This may result in tilting of the ham due to e.g. a load from the rotary knife of the cutting means. If the ham is tilted, it is cut diagonally to yield defective slices out from the central portion, where normal slices are commonly produced, as well as non-standard slices from both, leading and trailing, end portion of the ham. The productivity of ham slices will thus be declined. It is an object of the present invention, in view of the above predicament, to provide a food slicer having a feeding means of the belt conveyor type and adapted for holding a lump of food securely even when the food is shortened in cutting so as to avoid production of non-standard slices caused by tilting of the food and to increase the productivity of food slices. DE-U-82 29 720 discloses a food slicer having a feeding means including a belt conveyor for holding and feeding a lump of food and a cutting means for cutting the food into slices from one end. Claw devices suspended above the conveyor for motion parallel to the conveyor. The claw device grips the block of food and feeds the food on the conveyor by means of an intermittent feed device so as to prevent wear of the cutting device. The invention provides a food slicer including a feeding means for continuous feeding and comprising a pair of belt conveyors positioned opposite each other for holding there between a lump of food and feeding the lump of food in a feeding direction, and cutting means for cutting the food fed by the feeding means into slices from a first end in a succession, and characterised by, an end detecting means for detecting end portions of the food fed by the feeding means; a retaining member arranged moveable with the food in a feeding direction of the feeding means and retractable at substantially a right angle to the feeding direction for penetrating into and departing from the food; and a controlling means responsive to a detection signal of the end detecting means for causing the retaining member to penetrate into and hold a second end of the food, distal from said first end, and travel with the food until the second end of the food comes close to the cutting means. The food slicer of the present invention allows the lump of food to be held and conveyed between the two belt conveyors of the feeding means to the cutting means and cut from its one end into slices in succession. Upon the one end of the food conveyed by the feeding means being detected by the end detecting means, the retaining member moves forward and penetrates into the other end of the food in response to the detection signal of the detecting means. The retaining member then holds and travels together with the food until the other end of the food arrives at the cutting means. Accordingly, when the lump of food becomes shorter as being sliced by the cutting means, it will be held in stability. The invention will now be described in more detail and by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a schematic view of a ham slicer showing one embodiment of the present invention; Figure 2 is an explanatory view of drive mechanisms for a feeding means and a cutting means; Fig. 3 is a side view showing a holding mechanism; Fig. 4 is a cross sectional view taken along the line A-A of Fig. 3; Fig. 5 is a cross sectional view taken along the line B-B of Fig. 3; Fig. 6 is a front view of a holding base; Fig. 7 is a cross sectional view taken along the line C-C of Fig. 6; Fig. 8 is a schematic plan view showing an end detecting means; Fig. 9 is a schematic diagram of a controlling means; and Figs. 10 to 13 are explanatory view showing steps of action of the ham slicer. DETAILED DESCRIPTION OF THE INVENTION One embodiment of the present invention will be described referring to the accompanying drawings. The embodiment of the present invention is illustrated in the form of a ham slicer which is one mode of a food slicer. As shown in Fig. 1, the food slicer 1 comprises a feeding means 10 for conveying a loaf of ham H supplied as a lump of food, an end detecting means 20 for detecting both end portions of the ham H, a cutting means 30 for cutting the ham H fed by the feeding means 10 into slices in a succession, a belt conveyor 40 for receiving and conveying slices of ham dropped from the cutting means 30 to the outside of the ham slicer 1, and a holding mechanism 50 for holding the ham H loaded by the feeding means with a retaining member (described later). The feeding means 10 includes a pair of belt conveyor 11 and 12 disposed vertically opposite to each other to hold the ham H from both sides. Referring to Fig. 2, the belt conveyors 11 and 12 are driven by two drive shafts 13 and 14 respectively which are linked to each other by a pair of toothed wheels 15 for rotation at a constant speed in opposite directions to each other. The drive shaft 14 is coupled at the other end to a servo motor 16 for driving the belt conveyors 11 and 12 to feed the ham H in a downward direction. Also, a guide member 17 is disposed beneath the two belt conveyors 11 and 12. The guide member 17 has a thick disk shape having an opening 18 provided in the center thereof through which the ham H is passed and a downward groove provided in a top side thereof for clearing the retaining member (described later), as shown in Fig. 10. In addition, an automatic loader is provided above the feeding means for loading loafs of ham H one by one into the feeding means 10, as is not illustrated. The end detecting means 20 comprises a light emitter 21 and a light receiver 22 made of optical sensors. As apparent from Figs. 1, 8, and 10, the light emitter 21 and the light receiver 22 are arranged at a horizontal level which is slightly above the top end of the belt conveyor 11 and substantially perpendicular to the holding surface of the belt conveyor 11. As a leading portion of the ham H which is smaller in the diameter than its central portion passes across the level, a beam of light emitted from the light emitter 21 which is generally interrupted by the central portion of the ham H and not received by the light receiver 22 runs to the light receiver 12 thus detecting the presence of the leading portion of the ham H. The cutting means 30 includes a rotary knife 31 mounted adjacent to and beneath the feeding means 10. As shown in Fig. 2, the rotary knife 31 is driven by a drive shaft 32 which is linked by a pulley and belt mechanism 33 to a servo motor 34. The drive shaft 32 has a notched disk 35 mounted to the lower end thereof for allowing an optical sensor 36 to count rotations of the drive shaft 32 (thus, the rotary knife 31). The belt conveyor 40 is driven for rotating movement by a servo motor 41. The holding mechanism 50 will now be explained referring to Figs. 3 to 7. The holding mechanism 50 includes a rail plate 51, a slide base 52, and a hold base 53. The rail plate 51 is vertically mounted by a spacer 54 to a platform 2 of the ham slicer 1 and has its two sides shaped of a rail form of which cross section is triangular. Four rollers 55, two on each side, are mounted on the back of the slide base 52. With their rollers 55 having a V-shaped circumferentially extending recess in a periphery thereof running directly on both sides of the rail plate 51, the vertical movement of the slice base 52 is maintained supported by the rail plate 51. A timing belt 59 is mounted between a timing pulley 57 joined to the output shaft of a servo motor 56 and a timing pulley 58 mounted rotatably to an upper region of the back of the rail plate 51. A connecting strip 60 is mounted at one end to the back of the slide base 52. The other end of the connecting strip 60 is mounted to the timing belt 59 as extends rearwardly of the rail plate 51 through a vertically extending slot 61 provided in the rail plate 51. This allows the slice base 52 to be moved vertically by the rotating action of the servo motor 56 as being guided with the rail plate 51. The output shaft of the servo motor 56 has a notched disk 62 mounted on rear end thereof for allowing an optical sensor 63 disposed opposite to the disk 62 to define the upper and lower limits of the vertical movement of the slice base 52. The holding base 53 comprises a rear plate 53a and two side plates 53b forming substantially a C shape in cross section. The rear plate 53a is mounted to the front end of a connecting plate 64 extending forward from the front side of the slide base 52. As shown in Figs.1 and 10, the two side plates 53b of the holding base 53 are arranged to extend forward into between the holding surfaces of the two belt conveyors 11 and 12 so that they can support the side of the ham H fed between the two belt conveyors 11 and 12. A swing arm 65 is pivotably mounted on the side plates 53b for forward and backward swing movements. The retaining member 67 having four forwardly bent claws 66 of a hook shape is mounted to the lowermost end of the swing arm 65. Also, an air cylinder 68 is mounted on the rear plate 53a of the holding base 53 and connected to an air compressor (not shown). The air cylinder 68 is provided with a cylinder rod 68a which is pivotably linked at the lower end with one end of a connecting rod 69. The other end of the connecting rod 69 is pivotably linked to the swing arm 65. Accordingly, as the cylinder 68 actuates, the swing arm 65 is swung thus to horizontally move the claws 66 of the retaining member 67 in forward and backward directions, as shown in Fig. 7. Fig. 9 shows the controlling means 80 installed in the ham slicer 1. The controlling means 11 is electrically connected to the optical sensors 20, 36, and 63, the servo motors 16, 34, 41, and 56, and the air cylinder 68. The controlling means 80 may be a microcomputer having an input/output interface, a CPU, and memories (not shown) and accompanied with drivers (not shown) for the servo motors and a setting device (not shown) for controlling the thickness of a slice of the ham H. The action of the ham slicer 1 will be explained. As the ham slicer 1 has been activated, the two belt conveyors 11 and 12 of the feeding means 10 and the rotary knife 31 of the cutting means 30 are driven for running at constant speeds. The loaf of ham H loaded from the automatic loader to the feeding means 10 is transferred downwardly between the two belt conveyors 11 and 12 to the cutting means 30. The ham H upon reaching the cutting means 30 is cut from its leading end by the rotary knife 31 into slices of a predetermined thickness which are then dropped and conveyed on the belt conveyor 40 to the outside. At the starting of the action, the slide base 52 and the holding base 53 remain at their standby position or the upper limit of the vertical movement determined by the optical sensor 63, as shown in Fig. 10. In the standby state, the air cylinder 68 is kept retracting and the retaining member 67 stays backward allowing its claws 66 to be away from the ham H. When the trailing portion of the ham H fed by the feeding means 10 comes to the end detecting means (optical sensor) 20 which in turn generates and transmits a detection signal to the controlling means 80, the controlling means 80 calculates a period of time to a moment when the trailing portion of the ham H reaches the level of the claws 66 with reference to the feeding speed of the feeding means 10. Upon the period of time having elapsed, the air cylinder 68 is actuated to move the retaining member 67 forward so that the claws 66 of the retaining member 67 penetrate into the ham H as shown in Fig. 11. Simultaneously, the controlling means 80 lowers the slide base 52 at a speed equal to the feeding speed of the feeding means 10 for feeding the ham H, allowing the retaining member 67 to move downward with the ham H. Fig. 12 shows the slide base 52 having been lowered and arrived at the lower limit of its vertical movement with the retaining member 67 holding the ham H as its state being detected by the optical sensor 63. At the time, the controlling means 80 causes the air cylinder 68 to retract with the retaining member 67 moved backward. This allows the claws 66 to depart from the ham H and the downward movement of the slide base 52 to be ceased. The trailing portion of the ham H into which the claws 66 have penetrated involves production of non-standard slices, and when it being pressed downward by a succeeding loaf of ham H, sliced by the rotary knife 31 and dropped. Fig. 13 shows that the trailing portion of the ham H has been sliced off and the leading end of the succeeding ham H arrives at the cutting position of the rotary knife 31. The slide base 52 after stopping its downward movement starts its upward movement with the retaining member 67 kept backward and stays at its standby state, shown in Fig. 10, upon reaching the upper limit. According to the embodiment of the present invention, the retaining member 67 causes its claws 66 to penetrate into and hold the trailing portion of the ham H, and move together with the ham H until the trailing portion of the ham H arrives at the cutting position of the rotary knife 31. Hence, when the central portion of the ham H becomes short during the cutting action, it is prevented from being tilted by an external force from e.g. the rotary knife 31 and cut into defective slices. As the result, the productivity of ham slices will be increased. It would be understood that the ham slicer of the prescribed embodiment is illustrative and the present invention is applicable to any other types of a food slicer than the ham slicer. Also, the present invention is not limited to the downward feeding action of the feeding means in the embodiment but may be applicable to a food slicer in which a lump of food is fed diagonally or horizontally by its feeding means. Although the retaining member in the embodiment is driven by a power device for movement with a lump of food, it may follow a lump of food as is driven by a force of the food derived from the feeding means. The retaining member in the embodiment is not limited to single one but a pair of the retaining members may be used as arranged on both sides of a lump of food fed by the feeding means. As the food is held from both sides with the two retaining members, it will be more stably maintained. Although the retaining member departs from the food as is moved backward, it may be arranged to retract together with the food and then, be separated from the same by an appropriate means.

Claims: A food slicer (1) including a feeding means (10) for continuous feeding and comprising a pair of belt conveyors (11, 12) positioned opposite each other for holding there between a lump of food (H) and feeding the lump of food in a feeding direction, and cutting means for cutting the food fed by the feeding means into slices from a first end in a succession, and characterised by, an end detecting means (20) for detecting end portions of the food fed by the feeding means (10); a retaining member (67) arranged moveable with the food in a feeding direction of the feeding means (10) and retractable at substantially a right angle to the feeding direction for penetrating into and departing from the food (H); and a controlling means (80) responsive to a detection signal of the end detecting means (20) for causing the retaining member (67) to penetrate into and hold a second end of the food, distal from said first end, and travel with the food until the second end of the food comes close to the cutting means.

Inventors: TERAI MASAO, TERAI, MASAO
Applicants: RYOWA & CO LTD, RYOWA CO., LTD.
Application year: 1996
Main classification: B26D7
IPC codes: B26D7, A22C17, B26D3