CA2384008A1 - A self adjusting dual caster support system - Google Patents
A self adjusting dual caster support system Download PDFInfo
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- CA2384008A1 CA2384008A1 CA 2384008 CA2384008A CA2384008A1 CA 2384008 A1 CA2384008 A1 CA 2384008A1 CA 2384008 CA2384008 CA 2384008 CA 2384008 A CA2384008 A CA 2384008A CA 2384008 A1 CA2384008 A1 CA 2384008A1
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- support
- turntable
- caster
- dual
- rollers
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- 230000009977 dual effect Effects 0.000 title claims abstract description 84
- 230000007246 mechanism Effects 0.000 abstract description 6
- 230000000694 effects Effects 0.000 abstract description 4
- 238000000034 method Methods 0.000 description 9
- 239000005022 packaging material Substances 0.000 description 6
- 235000004443 Ricinus communis Nutrition 0.000 description 5
- 229910000831 Steel Inorganic materials 0.000 description 5
- 239000010959 steel Substances 0.000 description 5
- 230000000712 assembly Effects 0.000 description 4
- 238000000429 assembly Methods 0.000 description 4
- 239000000725 suspension Substances 0.000 description 4
- 229910000746 Structural steel Inorganic materials 0.000 description 3
- 238000012856 packing Methods 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000012423 maintenance Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000004806 packaging method and process Methods 0.000 description 2
- 240000000528 Ricinus communis Species 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 230000036541 health Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000002028 premature Effects 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
- 238000011105 stabilization Methods 0.000 description 1
- 238000004078 waterproofing Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65B—MACHINES, APPARATUS OR DEVICES FOR, OR METHODS OF, PACKAGING ARTICLES OR MATERIALS; UNPACKING
- B65B11/00—Wrapping, e.g. partially or wholly enclosing, articles or quantities of material, in strips, sheets or blanks, of flexible material
- B65B11/04—Wrapping, e.g. partially or wholly enclosing, articles or quantities of material, in strips, sheets or blanks, of flexible material the articles being rotated
- B65B11/045—Wrapping, e.g. partially or wholly enclosing, articles or quantities of material, in strips, sheets or blanks, of flexible material the articles being rotated by rotating platforms supporting the articles
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Purses, Travelling Bags, Baskets, Or Suitcases (AREA)
Abstract
A stretch wrapping machine having a base assembly comprising a turntable. The turntable is supported by a plurality of dual caster supports. A dual caster support comprises two rollers and is pivotally mounted to the base assembly of the stretch wrapping machine. The dual caster support counteracts common effects encountered with conventional caster supports, causing short live time and high wearing of the support and bearing mechanism. The dual caster support also provides a stretch wrapping machine operating at low noise levels.
Description
Description of the invention Stretchwrapping Machine with self adjusting Dual caster support Field of the Invention [0001] The instant invention relates to an apparatus for stretch wrapping a load with packaging material, and, more particularly, to an apparatus comprising a turntable for providing relative rotation of the load.
Background of the Invention [0002] Various packaging techniques have been used to build a load of unit products and subsequently wrap them for transportation, storage, containment and stabilization, protection and waterproofing. One system uses stretch wrapping machines to stretch, dispense and wrap stretch packaging material around a load. Stretch wrapping can be performed as an automated or semi-automated packaging technique that dispenses and wraps packaging material in a stretch condition around a load on a pallet to cover and contain the load. When stretch wrapping loads with a sheet of stretch wrap packaging material, relative rotation is provided between a film web dispenser and a load. This is generally accomplished by one of two methods. Either the dispenser is rotated around a stationary load, or the load is rotated on a turntable next to a stationary dispenser.
[0003[ Conventional stretch wrapping machines comprising a turntable are well known in the art, as for example illustrated in U.S. Pat. No. 4,248,031 to Del Pozo, Jr., issued February 3, 1981, in U.S. Pat. No. 4,607,476 to Fulton, Jr., issued August 26, 1986, in U.S. Pat. No. 4,807,427 to Casteel et al., issued February 28, 1989, in U.S.
Pat. No.
5,546,730 to Newell et al., issued August 20, 1996, and in U.S. Pat. No.
5,562,258 to Jones, Sr., et al., issued October 15, 1996. Although the basic principles of stretch wrapping machines are well described in the prior art, particular aspects of such devices are subject to constant improvements.
[0004] Besides the aspect of functionality and practicability of stretch wrapping machines, there exists a need for a proper maintenance of such devices, which is desirable for obvious reasons, including the aspects of cost reduction in operating the stretch wrapping machine, as well as an increased lifespan of the stretch wrapping machine. One of the critical components in this regard is the above-mentioned turntable.
The traditional support for the turntable utilizes either ring bearings or caster assemblies, which often suffer under unequally distributed stress forces from the turntable. This in turn affects the longevity and effectiveness of the supporting devices.
[0005] The traditional caster supports for turntables usually also operate at certain elevated noise levels. When the stretch Wapping machine is run on a factory floor together with other noise producing devices, the threshold of 90 dB for permissible noise exposure for a worker during an eight hour work day, as administered by the United States Occupational Safety & Health Administration (OSHA) in standard 1910.95, is likely to become a serious problem.
[0006] It would be advantageous to provide a support and bearing mechanism for a turntable for stretch wrapping machines, which is robust, and inexpensive and undemanding in manufacture and maintenance. It would be of further advantage to provide a support and bearing mechanism for a turntable for stretch wrapping machines, which operates at reduced noise levels.
Object of the Invention [0007] In an attempt to overcome the limitations of the prior art it is an object of the instant invention to provide a support and bearing mechanism for turntables of stretch wrapping machines, which counteracts common effects encountered with conventional caster supports causing short live times and high wearing of the support and bearing mechanism.
[0008] It is further an object of the instant invention to provide a stretch wrapping machine operating at low noise levels.
Summary of the Invention [0009] In accordance with an aspect of the instant invention, there is provided a stretch wrapping machine having a base assembly, the base assembly having a turntable and a plurality of dual caster supports, each dual caster support comprising a support member supporting two rollers in spaced apart relation for load bearing, the rollers and support member mounted for motion of the roller approximately normal to a plane of said turntable, said rollers for rollingly engaging said turntable, wherein the motion of the rollers is such that one roller moves down while the other moves up.
Preferably, the dual caster support is pivotally mounted between the two rollers.
[0010] In accordance with an aspect of the instant invention, there is further provided a stretch wrapping machine wherein the dual caster support is movably mounted in a vertical direction, the vertical direction being substantially normal to the plane of the turntable.
Brief Description of the Drawings [0011] Exemplary embodiments of the instant invention will be described in conjunction with the following drawings, in which similar reference numbers designate similar items:
[0012] Figure la presents a side view of a dual caster support for a low profile stretch wrapper mounted to a base structure according to a first embodiment of the instant invention;
[0013] Figure 1b presents a top view of a dual caster support for a low profile stretch wrapper mounted to a base structure according to a first embodiment of the instant invention;
[0014] Figure lc presents a side view of a dual caster support for a high profile stretch wrapper mounted to a base structure according to a second embodiment of the instant invention;
[0015] Figure 2a presents a top view of an arrangement of three dual caster supports for a high profile stretch wrapper, for supporting a turntable;
[0016] Figure 2b presents a top view of an arrangement of six dual caster supports for a low profile stretch wrapper, for supporting a turntable;
[0017] Figure 2c presents a side view of a two arbitrary dual caster supports supporting a turntable;
[0018] Figure 3 presents a side view dual caster support according to a second embodiment of the instant invention;
[0019] Figure 4 presents a side view dual caster support according to a third embodiment of the instant invention;
[0020] Figure 5 presents a side view dual caster support according to a fourth embodiment of the instant invention;
[0021 ] Figure 6 presents a side view dual caster support according to a fifth embodiment of the instant invention;
[0022] Figure 7 presents a side view dual caster support according to a sixth embodiment of the instant invention;
[0023) Figure 8 presents a side view dual caster support according to a seventh embodiment of the instant invention;
[0024] Figure 9 presents a side view dual caster support according to an eighth embodiment of the instant invention;
[0025] Figure 10 presents a side view dual caster support according to a ninth embodiment of the instant invention; and [0026) Figure I 1 presents a top view of a dual caster arrangement according to a tenth embodiment of the instant invention.
Detailed Description of the Invention [0027] The instant invention will now be described with reference to a semi-automatic stretch wrapping machine, which comprises a turntable, providing relative rotation of a load to be packed with respect to a packaging material dispenser. In the following, this particular stretch wrapping machine is referred to as a "stretch wrapper". Of course, the instant invention is not limited to semi-automatic stretch wrapping machines, but is equally applicable to automatic stretch wrapping machines, manual stretch wrapping machines, or any kind of packing machines, which utilize a turntable to provide relative rotation between the load and the packaging material dispenser.
[0028] A stretch wrapper for wrapping a load commonly comprises the following elements: l) a base assembly including a turntable, ii) a tower assembly, and iii) a carriage assembly. The carriage assembly includes the packing material holder and the packing material dispenser. The carriage assembly is movably mounted to the tower assembly, as to allow for a free vertical movement of the carriage assembly.
Thus, the carriage assembly goes up and down the tower assembly, as to wrap the load from its bottom to its top, or vice versa from its top to its bottom.
[0029] The main function of the tower assembly is to support the carriage assembly, as described above. Optionally, the tower assembly comprises a control panel, or any other device necessary to operate the stretch wrapper. Depending on the design of the stretch wrapper, there exist different possibilities how the tower assembly is supported. In one possibility, the tower assembly is fixed or welded to the base assembly.
Alternatively, the tower assembly is bolted to the base assembly.
[0030] There exist at least two different types of base assemblies. One type of base assembly relates to a low profile model of a stretch wrapper. In the low profile model, the base assembly exhibits a substantially low raising level compared to standing ground.
The base assembly of the low profile model usually comprises a steel plate, which is reinforced with structurally steel, and certain other components, which are placed on, or welded to the steel plate. In the high profile model, the base assembly exhibits a substantially high raising level compared to standing ground. The base assembly of the high profile model usually comprises a frame fabricated from structural steel.
The steel plate and the structural steel frame form a base structure of the base assembly. In both cases, the base assembly further comprises a turntable, and a fixture for supporting the turntable, the fixture mounted to the base structure.
[0031] Two different methods are commonly employed to provide support for the turntable, namely a ring bearing support, and a mufti-point caster support.
The ring bearing support comprises a ring bearing, the bottom part of the ring bearing being fixed to the base structure. The turntable is placed on top of the ring bearing, and is bolted to the ring bearing. The mufti-point caster support comprises a plurality of casters. The casters are mounted to the base structure in a way that when the turntable is placed onto the casters, the casters are approximately evenly distributed over the area of the turntable.
_ ._ .__ . ...__ .._~ .__.. __._..~_.y.,..-,.~,.""",......,.,..-......."~~_~
..._. _. .
The casters are mounted to the base structure by means of caster bases. The caster bases in turn are removably mounted to the base assembly, or fixed to the base assembly. Of the two methods described above, the ring bearing support, which is the method of choice when a large contact area between base structure and turntable is sought after, is considerably more expensive than the multi-point caster support.
[0032] The fact that steel plates and structural steel frames, i.e. the base structures of base assemblies, hardly ever provide an ideal plane surface causes several problems associated with the turntable support methods described above. For the ring bearing support, a lack of flatness results in unequally distributed stress forces, which lead to undesirable ring bearing stress, and reduce effectiveness of the stretch wrapper, and longevity of the turntable support. For the mufti point caster support method, a lack of flatness causes a situation, in which not all casters are simultaneously in constant contact with the turntable. Since in this case not all casters are supporting the turntable, as it was intended to be, some of the casters out of the plurality of casters carry a greater weight, and are therefore exposed to overloading. The consequences of overloading include caster deformation, caster cracks, and premature caster wear, among others. This in turn afflicts the casters longevity anywhere from short to long term. In addition, when a caster that has lost contact with the turntable regains contact with the turntable, the process of reengagement is generally accompanied by an impact and a certain amount of stress exhibited on the caster. The impact on reengagement usually has similar effects on the caster as those described for the case of overloading.
[0033] Referring now to Figure 1 a, a side view down the latitudinal direction of a dual caster support 1 for use with a low profile stretch wrapper is shown, according to a first preferred embodiment of the instant invention. A plurality of dual caster supports is used for supporting a disc-shaped turntable (not shown). The dual caster support 1 comprises a caster base 11, and two cylindrical rollers 12a, 12b. The caster base 11 has the form of an elongated parallelepiped, having at least two longitudinal sidewalk, possibly two latitudinal sidewalk, and optionally a bottom section. The caster base 11 serves as a support member supporting the two rollers 12a, 12b. The rollers 12a, 12b are mounted in close vicinity to the two latitudinal sides, the axis of rotation of each roller being substantially orthogonal to the direction of longitudinal extension of the caster base 11.
Furthermore, the direction of longitudinal extension of the caster base 11 is substantially orthogonal to the radius of the turntable. The diameter of the roller exceeds the height of the sidewalls of the caster base 11, so that rollers 12a, 12b, which are rollably mounted between the longitudinal sidewalk of the caster base 11, are able to rollably engage the turntable. The dual caster support 1 is mountably supported in a point, which essentially lies in the middle between the two latitudinal sidewalls, and in the middle between the two longitudinal sidewalls. Furthermore, the dual caster support 1 is pivotally mounted, the axis of pivotal motion being substantially orthogonal to the direction of longitudinal extension of the caster base. This allows the caster base 11 to swing up and down. Thus, when one roller 12a is in the up-position, the other roller 12b is in the down-position, and vice versa.. The dual caster support 1 is therefore vertically self adjusting when supporting the turntable. Due to the pivot mechanism, the dual caster support 1 is substantially in constant contact with a surface of the turntable.
[0034] The caster base 11 is supported by a suspension system, the suspension system being for mounting the dual caster support 1 to a base structure 2. The suspension system is made from at least one round spring disc 3. The at least one round spring disc 3 is placed between the caster base 11 and the base structure 2, and is secured into place by vertical shafts 4 fixed onto the base structure. Optionally, a plurality of round spring discs 3 is used in engaging the caster base 11 and the base structure 2, the plurality of round spring discs 3 supporting the dual caster support 1 in a plurality of points.
Alternatively, other spring assemblies, like for example leaf springs or other type of compound springs, or any other suitable suspension systems are used instead of the at least one round spring disc. The use of the spring discs favorably adds another degree of freedom in self adjusting motion to the dual caster 1. Besides the pivotal motion described above, the dual caster is also free to move up and down in a vertical direction, the vertical direction being substantially normal to a plane of the turntable. This motion greatly facilitates the self adjustment of the dual caster support 1 as to maintain essentially constant contact between the rollers 12a, 12b of the dual caster support 1, and the turntable.
[0035] Referring now to Figure 1 b, a top view down the latitudinal direction of a dual caster support 1 for use with a low profile stretch wrapper is shown, according to a first preferred embodiment of the instant invention. The two rollers 12a, 12 are mounted to the caster base 11 in vicinity to its two latitudinal sides.
[0036] Referring now to Figure 1 c, a side view down the latitudinal direction of a dual caster support 100 for use with a high profile stretch wrapper is shown, according to a second preferred embodiment of the instant invention. When the dual caster support 100 is used with the high profile stretch wrapper, a substantially greater clearance between the caster base 111 and the base structure 120 is obtained, compared to the use with a low profile stretch wrapper. This allows for the use of rollers 112a, 112b having a substantially large diameter and greater capacity. The caster support 100 is mounted to a vertical square tube 141 through a horizontal shaft 140, allowing for a pivotal motion of the dual caster support. T'he vertical square tube 141 is mounted to the base structure 120.. Alternatively, another system instead of a horizontal shaft is chosen, in order to obtain a pivot effect of the dual caster support 100. In Figure 2a, a top view of the base assembly of a high profile stretch wrapper is shown, wherein three dual caster supports 100 are mounted to the base structure 120. No vertical motion of the dual caster support is necessary in high profile models since the three dual caster supports 100 define the plane of the turntable (not shown j, therefore being always in contact with it.
[0037] In a low profile stretch wrapper, the clearance between the turntable and the base structure is reduced. Therefore, rollers with smaller diameter and reduced capacity are required. In this case, it is advantageous to use six dual casters supports to support the turntable. In Figure 2b, it is illustrated how four of the dual caster supports 1 are approximate equally distributed towards the edge of the turntable on a circumference of a circle, having the same midpoint as the turntable 6, but a somewhat smaller radius, whereas two dual caster supports 1 are located towards the inner region of the turntable on a -circumference of a circle, having the same midpoint as the turntable 6, but a substantially smaller radius.
[0038] Given that the turntable 6 is not plane, under low loads only three of the six dual casters supports are likely to be in contact with the turntable. As the amount of load on those three theoretical contact support points increases, the dual caster supports will vertically move and lower themselves, until the other three dual caster supports gain contact with the turntable. Under heavy loads, all dual caster supports are likely to be in contact with, and support the turntable.
[0039] In Figure 2c a side view is shown of how two arbitrary dual caster supports Sa, Sb support a turntable 6. The dual caster supports Sa, Sb are pivotally mounted, pivoting in a direction 7. In the case that there are a total of six dual caster supports present, an additional degree of freedom is necessary to ensure that each roller of each of the dual caster supports is essentially in constant contact with the turntable.
Optionally, a spring systems allows the dual caster supports Sa, 5b not only to perform pivotal motion, but also motion along a vertical direction 8.
[0040) The instant invention is beneficial to stretch wrappers comprising a turntable, and caster support thereof, since under heavy load conditions, all dual casters supports are likely to be in permanent contact with, and support the turntable. The loss and regain of contact between a castor and a heavily loaded turntable is virtually eliminated. For lighter loads, occasional loss of contact is damped due to pivoting motion of the dual caster support. The loss of contact under lighter loads is however benign to castor's longevity.
The overloading problem is greatly reduced due to the fact that all castors are supporting the turntable when under heavy loads. Furthermore, the stretch wrappers operating a turntable supported by dual caster support usually operate at low noise levels, and are thus beneficial in providing a healthy working environment. The dual caster support described in the instant invention produces less noise than the traditional caster support, since each dual caste support is essentially constantly engaged with the turntable. Thus, high background noise levels , which occur when a caster regains contact with the turntable, are substantially eliminated.
[0041 ] Referring now to Figure 3, a third preferred embodiment of the instant invention is shown. A dual caster support comprises a support member 10 and two rollers 12a, 12b, mounted to the support member. The dual caster support further comprises a mounting member 13 for mounting the support member to the base assembly. The mounting member 13 is pivotally mounted to the support member, so that the roller 12a movers up, when the roller 12b moves down.
[0042) Referring now to Figure 4, a fourth preferred embodiment of the instant invention is shown. A dual caster support comprises a support member 10 and two rollers 12a, 12b, mounted to the support member. The dual caster support further comprises a mounting member 14, for mounting the support member to the base assembly. The mounting member 14 comprises a spring allowing for vertical movement of the support member 10.
The mounting member 14 is pivotally mounted to the support member, so that the roller 12a movers up, when the roller 12b moves down.
[0043] Referring now to Figure S, a fifth preferred embodiment of the instant invention is shown. A dual caster support comprises a support member 10 and two rollers 12a, 12b, mounted to the support member. The dual caster support further comprises a mounting member 13 for mounting the support member to the base assembly. Each roller 12a, 12b is mounted to the support member 10 by a spring mounting member 15a, 15b, allowing for individual vertical movement of each of the rollers 12a, 12b.
[0044] Referring now to Figure 6, a sixth preferred embodiment of the instant invention is shown. A dual caster support comprises a support member 10 and two rollers 12a, 12b, mounted to the support member. The dual caster support further comprises a mounting member 14, for mounting the support member to the base assembly. The mounting member 14 comprises a spring allowing for vertical movement of the support member 10.
Each roller 12a, 12b is mounted to the support member 10 by a spring mounting member 15a, 15b, allowing for individual vertical movement of each of the rollers 12a, 12b.
[0045] Referring now to Figure 7, a seventh preferred embodiment of the instant invention is shown. A dual caster support comprises a support member 10 and two rollers 12a, 12b, mounted to the support member. The dual caster support further comprises a mounting member 13 for mounting the support member to the base assembly. The mounting member 13 is pivotally mounted to the support member, so that the roller 12a movers up, when the roller 12b moves down. Each roller 12a, 12b is mounted to the support member 10 by a spring mounting member 15a, 15b, allowing for individual vertical movement of each of the rollers 12a, 12b.
[0046] Referring now to Figure 8, a eighth preferred embodiment of the instant invention is shown. A dual caster support comprises a support member 10 and two rollers 12a, 12b, mounted to the support member. The dual caster support further comprises a mounting member 14, for mounting the support member to the base assembly. The mounting member 14 comprises a spring al lowing for vertical movement of the support member 10.
The mounting member 14 is pivotally mounted to the support member, so that the roller 12a movers up, when the roller 12b moves down. Each roller 12a, 12b is mounted to the support member 10 by a spring mounting member 15a, 15b, allowing for individual vertical movement of each of the rollers 12a, 12b.
[0047] Referring now to Figure 9, an ninth preferred embodiment of the instant invention is shown. A dual caster support comprises a support member 10 and two rollers 12a, 12b.
The caster support 10 further comprises a tube member 17, the tube member 17 mounted to the support member 10, a direction of longitudinal extension of the tube member 17 being substantially parallel to a direction of longitudinal extension of the support member. The rollers 12a, 12b are mounted to the tube member 17 by means of mounting pistons 16a, 16b. The tube member 17 and the mounting pistons 16a, 16b form a system of communicating vessels, and are filled with a hydraulic liquid. Thus, when the roller 16a moves up, a hydraulic pressure is exerted on roller 16b, causing roller 16b to move down.
[0048] The principle described in the context of Figure 9 is not restricted to two rollers, but equally applies to a plurality of rollers and a plurality of mounting pistons. 'thus, referring to Figure 10, in a tenth preferred embodiment of the instant invention, a castor support comprises a tube member 17, three rollers 12a, 12b, 12c and three mounting pistons 16a, 16b, 16c.
[0049] An eleventh preferred embodiment of the instant invention is shown in Figure 11.
Three dual caster supports 22a, 22b, 22c support a turntable 6. Each of the dual caster supports 22a, 22a, 22b, 22e comprises two rollers 221x, 222a, 221b, 222b, and 221c, 222c, respectively. Here, the axis of rotation of the two rollers 221a and 222a coincide with a radius of the turntable 6. The same holds for the two rollers 221b, 222b and 221c, 222c. Alternatively, more than three dual castor supports provide support for a turntable 6, each of the dual caster supports comprising at least two rollers, the axes of each pair of rollers coinciding with a radius of the turntable.
[0050] Although the instant invention has been described with respect to specific embodiments thereof, various changes and modifications are easily carried out by those skilled in the art without departing from the scope of the invention.
Therefore, it is intended that the instant invention encompass such changes and modifications as fall within the scope of the appended claims.
Background of the Invention [0002] Various packaging techniques have been used to build a load of unit products and subsequently wrap them for transportation, storage, containment and stabilization, protection and waterproofing. One system uses stretch wrapping machines to stretch, dispense and wrap stretch packaging material around a load. Stretch wrapping can be performed as an automated or semi-automated packaging technique that dispenses and wraps packaging material in a stretch condition around a load on a pallet to cover and contain the load. When stretch wrapping loads with a sheet of stretch wrap packaging material, relative rotation is provided between a film web dispenser and a load. This is generally accomplished by one of two methods. Either the dispenser is rotated around a stationary load, or the load is rotated on a turntable next to a stationary dispenser.
[0003[ Conventional stretch wrapping machines comprising a turntable are well known in the art, as for example illustrated in U.S. Pat. No. 4,248,031 to Del Pozo, Jr., issued February 3, 1981, in U.S. Pat. No. 4,607,476 to Fulton, Jr., issued August 26, 1986, in U.S. Pat. No. 4,807,427 to Casteel et al., issued February 28, 1989, in U.S.
Pat. No.
5,546,730 to Newell et al., issued August 20, 1996, and in U.S. Pat. No.
5,562,258 to Jones, Sr., et al., issued October 15, 1996. Although the basic principles of stretch wrapping machines are well described in the prior art, particular aspects of such devices are subject to constant improvements.
[0004] Besides the aspect of functionality and practicability of stretch wrapping machines, there exists a need for a proper maintenance of such devices, which is desirable for obvious reasons, including the aspects of cost reduction in operating the stretch wrapping machine, as well as an increased lifespan of the stretch wrapping machine. One of the critical components in this regard is the above-mentioned turntable.
The traditional support for the turntable utilizes either ring bearings or caster assemblies, which often suffer under unequally distributed stress forces from the turntable. This in turn affects the longevity and effectiveness of the supporting devices.
[0005] The traditional caster supports for turntables usually also operate at certain elevated noise levels. When the stretch Wapping machine is run on a factory floor together with other noise producing devices, the threshold of 90 dB for permissible noise exposure for a worker during an eight hour work day, as administered by the United States Occupational Safety & Health Administration (OSHA) in standard 1910.95, is likely to become a serious problem.
[0006] It would be advantageous to provide a support and bearing mechanism for a turntable for stretch wrapping machines, which is robust, and inexpensive and undemanding in manufacture and maintenance. It would be of further advantage to provide a support and bearing mechanism for a turntable for stretch wrapping machines, which operates at reduced noise levels.
Object of the Invention [0007] In an attempt to overcome the limitations of the prior art it is an object of the instant invention to provide a support and bearing mechanism for turntables of stretch wrapping machines, which counteracts common effects encountered with conventional caster supports causing short live times and high wearing of the support and bearing mechanism.
[0008] It is further an object of the instant invention to provide a stretch wrapping machine operating at low noise levels.
Summary of the Invention [0009] In accordance with an aspect of the instant invention, there is provided a stretch wrapping machine having a base assembly, the base assembly having a turntable and a plurality of dual caster supports, each dual caster support comprising a support member supporting two rollers in spaced apart relation for load bearing, the rollers and support member mounted for motion of the roller approximately normal to a plane of said turntable, said rollers for rollingly engaging said turntable, wherein the motion of the rollers is such that one roller moves down while the other moves up.
Preferably, the dual caster support is pivotally mounted between the two rollers.
[0010] In accordance with an aspect of the instant invention, there is further provided a stretch wrapping machine wherein the dual caster support is movably mounted in a vertical direction, the vertical direction being substantially normal to the plane of the turntable.
Brief Description of the Drawings [0011] Exemplary embodiments of the instant invention will be described in conjunction with the following drawings, in which similar reference numbers designate similar items:
[0012] Figure la presents a side view of a dual caster support for a low profile stretch wrapper mounted to a base structure according to a first embodiment of the instant invention;
[0013] Figure 1b presents a top view of a dual caster support for a low profile stretch wrapper mounted to a base structure according to a first embodiment of the instant invention;
[0014] Figure lc presents a side view of a dual caster support for a high profile stretch wrapper mounted to a base structure according to a second embodiment of the instant invention;
[0015] Figure 2a presents a top view of an arrangement of three dual caster supports for a high profile stretch wrapper, for supporting a turntable;
[0016] Figure 2b presents a top view of an arrangement of six dual caster supports for a low profile stretch wrapper, for supporting a turntable;
[0017] Figure 2c presents a side view of a two arbitrary dual caster supports supporting a turntable;
[0018] Figure 3 presents a side view dual caster support according to a second embodiment of the instant invention;
[0019] Figure 4 presents a side view dual caster support according to a third embodiment of the instant invention;
[0020] Figure 5 presents a side view dual caster support according to a fourth embodiment of the instant invention;
[0021 ] Figure 6 presents a side view dual caster support according to a fifth embodiment of the instant invention;
[0022] Figure 7 presents a side view dual caster support according to a sixth embodiment of the instant invention;
[0023) Figure 8 presents a side view dual caster support according to a seventh embodiment of the instant invention;
[0024] Figure 9 presents a side view dual caster support according to an eighth embodiment of the instant invention;
[0025] Figure 10 presents a side view dual caster support according to a ninth embodiment of the instant invention; and [0026) Figure I 1 presents a top view of a dual caster arrangement according to a tenth embodiment of the instant invention.
Detailed Description of the Invention [0027] The instant invention will now be described with reference to a semi-automatic stretch wrapping machine, which comprises a turntable, providing relative rotation of a load to be packed with respect to a packaging material dispenser. In the following, this particular stretch wrapping machine is referred to as a "stretch wrapper". Of course, the instant invention is not limited to semi-automatic stretch wrapping machines, but is equally applicable to automatic stretch wrapping machines, manual stretch wrapping machines, or any kind of packing machines, which utilize a turntable to provide relative rotation between the load and the packaging material dispenser.
[0028] A stretch wrapper for wrapping a load commonly comprises the following elements: l) a base assembly including a turntable, ii) a tower assembly, and iii) a carriage assembly. The carriage assembly includes the packing material holder and the packing material dispenser. The carriage assembly is movably mounted to the tower assembly, as to allow for a free vertical movement of the carriage assembly.
Thus, the carriage assembly goes up and down the tower assembly, as to wrap the load from its bottom to its top, or vice versa from its top to its bottom.
[0029] The main function of the tower assembly is to support the carriage assembly, as described above. Optionally, the tower assembly comprises a control panel, or any other device necessary to operate the stretch wrapper. Depending on the design of the stretch wrapper, there exist different possibilities how the tower assembly is supported. In one possibility, the tower assembly is fixed or welded to the base assembly.
Alternatively, the tower assembly is bolted to the base assembly.
[0030] There exist at least two different types of base assemblies. One type of base assembly relates to a low profile model of a stretch wrapper. In the low profile model, the base assembly exhibits a substantially low raising level compared to standing ground.
The base assembly of the low profile model usually comprises a steel plate, which is reinforced with structurally steel, and certain other components, which are placed on, or welded to the steel plate. In the high profile model, the base assembly exhibits a substantially high raising level compared to standing ground. The base assembly of the high profile model usually comprises a frame fabricated from structural steel.
The steel plate and the structural steel frame form a base structure of the base assembly. In both cases, the base assembly further comprises a turntable, and a fixture for supporting the turntable, the fixture mounted to the base structure.
[0031] Two different methods are commonly employed to provide support for the turntable, namely a ring bearing support, and a mufti-point caster support.
The ring bearing support comprises a ring bearing, the bottom part of the ring bearing being fixed to the base structure. The turntable is placed on top of the ring bearing, and is bolted to the ring bearing. The mufti-point caster support comprises a plurality of casters. The casters are mounted to the base structure in a way that when the turntable is placed onto the casters, the casters are approximately evenly distributed over the area of the turntable.
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The casters are mounted to the base structure by means of caster bases. The caster bases in turn are removably mounted to the base assembly, or fixed to the base assembly. Of the two methods described above, the ring bearing support, which is the method of choice when a large contact area between base structure and turntable is sought after, is considerably more expensive than the multi-point caster support.
[0032] The fact that steel plates and structural steel frames, i.e. the base structures of base assemblies, hardly ever provide an ideal plane surface causes several problems associated with the turntable support methods described above. For the ring bearing support, a lack of flatness results in unequally distributed stress forces, which lead to undesirable ring bearing stress, and reduce effectiveness of the stretch wrapper, and longevity of the turntable support. For the mufti point caster support method, a lack of flatness causes a situation, in which not all casters are simultaneously in constant contact with the turntable. Since in this case not all casters are supporting the turntable, as it was intended to be, some of the casters out of the plurality of casters carry a greater weight, and are therefore exposed to overloading. The consequences of overloading include caster deformation, caster cracks, and premature caster wear, among others. This in turn afflicts the casters longevity anywhere from short to long term. In addition, when a caster that has lost contact with the turntable regains contact with the turntable, the process of reengagement is generally accompanied by an impact and a certain amount of stress exhibited on the caster. The impact on reengagement usually has similar effects on the caster as those described for the case of overloading.
[0033] Referring now to Figure 1 a, a side view down the latitudinal direction of a dual caster support 1 for use with a low profile stretch wrapper is shown, according to a first preferred embodiment of the instant invention. A plurality of dual caster supports is used for supporting a disc-shaped turntable (not shown). The dual caster support 1 comprises a caster base 11, and two cylindrical rollers 12a, 12b. The caster base 11 has the form of an elongated parallelepiped, having at least two longitudinal sidewalk, possibly two latitudinal sidewalk, and optionally a bottom section. The caster base 11 serves as a support member supporting the two rollers 12a, 12b. The rollers 12a, 12b are mounted in close vicinity to the two latitudinal sides, the axis of rotation of each roller being substantially orthogonal to the direction of longitudinal extension of the caster base 11.
Furthermore, the direction of longitudinal extension of the caster base 11 is substantially orthogonal to the radius of the turntable. The diameter of the roller exceeds the height of the sidewalls of the caster base 11, so that rollers 12a, 12b, which are rollably mounted between the longitudinal sidewalk of the caster base 11, are able to rollably engage the turntable. The dual caster support 1 is mountably supported in a point, which essentially lies in the middle between the two latitudinal sidewalls, and in the middle between the two longitudinal sidewalls. Furthermore, the dual caster support 1 is pivotally mounted, the axis of pivotal motion being substantially orthogonal to the direction of longitudinal extension of the caster base. This allows the caster base 11 to swing up and down. Thus, when one roller 12a is in the up-position, the other roller 12b is in the down-position, and vice versa.. The dual caster support 1 is therefore vertically self adjusting when supporting the turntable. Due to the pivot mechanism, the dual caster support 1 is substantially in constant contact with a surface of the turntable.
[0034] The caster base 11 is supported by a suspension system, the suspension system being for mounting the dual caster support 1 to a base structure 2. The suspension system is made from at least one round spring disc 3. The at least one round spring disc 3 is placed between the caster base 11 and the base structure 2, and is secured into place by vertical shafts 4 fixed onto the base structure. Optionally, a plurality of round spring discs 3 is used in engaging the caster base 11 and the base structure 2, the plurality of round spring discs 3 supporting the dual caster support 1 in a plurality of points.
Alternatively, other spring assemblies, like for example leaf springs or other type of compound springs, or any other suitable suspension systems are used instead of the at least one round spring disc. The use of the spring discs favorably adds another degree of freedom in self adjusting motion to the dual caster 1. Besides the pivotal motion described above, the dual caster is also free to move up and down in a vertical direction, the vertical direction being substantially normal to a plane of the turntable. This motion greatly facilitates the self adjustment of the dual caster support 1 as to maintain essentially constant contact between the rollers 12a, 12b of the dual caster support 1, and the turntable.
[0035] Referring now to Figure 1 b, a top view down the latitudinal direction of a dual caster support 1 for use with a low profile stretch wrapper is shown, according to a first preferred embodiment of the instant invention. The two rollers 12a, 12 are mounted to the caster base 11 in vicinity to its two latitudinal sides.
[0036] Referring now to Figure 1 c, a side view down the latitudinal direction of a dual caster support 100 for use with a high profile stretch wrapper is shown, according to a second preferred embodiment of the instant invention. When the dual caster support 100 is used with the high profile stretch wrapper, a substantially greater clearance between the caster base 111 and the base structure 120 is obtained, compared to the use with a low profile stretch wrapper. This allows for the use of rollers 112a, 112b having a substantially large diameter and greater capacity. The caster support 100 is mounted to a vertical square tube 141 through a horizontal shaft 140, allowing for a pivotal motion of the dual caster support. T'he vertical square tube 141 is mounted to the base structure 120.. Alternatively, another system instead of a horizontal shaft is chosen, in order to obtain a pivot effect of the dual caster support 100. In Figure 2a, a top view of the base assembly of a high profile stretch wrapper is shown, wherein three dual caster supports 100 are mounted to the base structure 120. No vertical motion of the dual caster support is necessary in high profile models since the three dual caster supports 100 define the plane of the turntable (not shown j, therefore being always in contact with it.
[0037] In a low profile stretch wrapper, the clearance between the turntable and the base structure is reduced. Therefore, rollers with smaller diameter and reduced capacity are required. In this case, it is advantageous to use six dual casters supports to support the turntable. In Figure 2b, it is illustrated how four of the dual caster supports 1 are approximate equally distributed towards the edge of the turntable on a circumference of a circle, having the same midpoint as the turntable 6, but a somewhat smaller radius, whereas two dual caster supports 1 are located towards the inner region of the turntable on a -circumference of a circle, having the same midpoint as the turntable 6, but a substantially smaller radius.
[0038] Given that the turntable 6 is not plane, under low loads only three of the six dual casters supports are likely to be in contact with the turntable. As the amount of load on those three theoretical contact support points increases, the dual caster supports will vertically move and lower themselves, until the other three dual caster supports gain contact with the turntable. Under heavy loads, all dual caster supports are likely to be in contact with, and support the turntable.
[0039] In Figure 2c a side view is shown of how two arbitrary dual caster supports Sa, Sb support a turntable 6. The dual caster supports Sa, Sb are pivotally mounted, pivoting in a direction 7. In the case that there are a total of six dual caster supports present, an additional degree of freedom is necessary to ensure that each roller of each of the dual caster supports is essentially in constant contact with the turntable.
Optionally, a spring systems allows the dual caster supports Sa, 5b not only to perform pivotal motion, but also motion along a vertical direction 8.
[0040) The instant invention is beneficial to stretch wrappers comprising a turntable, and caster support thereof, since under heavy load conditions, all dual casters supports are likely to be in permanent contact with, and support the turntable. The loss and regain of contact between a castor and a heavily loaded turntable is virtually eliminated. For lighter loads, occasional loss of contact is damped due to pivoting motion of the dual caster support. The loss of contact under lighter loads is however benign to castor's longevity.
The overloading problem is greatly reduced due to the fact that all castors are supporting the turntable when under heavy loads. Furthermore, the stretch wrappers operating a turntable supported by dual caster support usually operate at low noise levels, and are thus beneficial in providing a healthy working environment. The dual caster support described in the instant invention produces less noise than the traditional caster support, since each dual caste support is essentially constantly engaged with the turntable. Thus, high background noise levels , which occur when a caster regains contact with the turntable, are substantially eliminated.
[0041 ] Referring now to Figure 3, a third preferred embodiment of the instant invention is shown. A dual caster support comprises a support member 10 and two rollers 12a, 12b, mounted to the support member. The dual caster support further comprises a mounting member 13 for mounting the support member to the base assembly. The mounting member 13 is pivotally mounted to the support member, so that the roller 12a movers up, when the roller 12b moves down.
[0042) Referring now to Figure 4, a fourth preferred embodiment of the instant invention is shown. A dual caster support comprises a support member 10 and two rollers 12a, 12b, mounted to the support member. The dual caster support further comprises a mounting member 14, for mounting the support member to the base assembly. The mounting member 14 comprises a spring allowing for vertical movement of the support member 10.
The mounting member 14 is pivotally mounted to the support member, so that the roller 12a movers up, when the roller 12b moves down.
[0043] Referring now to Figure S, a fifth preferred embodiment of the instant invention is shown. A dual caster support comprises a support member 10 and two rollers 12a, 12b, mounted to the support member. The dual caster support further comprises a mounting member 13 for mounting the support member to the base assembly. Each roller 12a, 12b is mounted to the support member 10 by a spring mounting member 15a, 15b, allowing for individual vertical movement of each of the rollers 12a, 12b.
[0044] Referring now to Figure 6, a sixth preferred embodiment of the instant invention is shown. A dual caster support comprises a support member 10 and two rollers 12a, 12b, mounted to the support member. The dual caster support further comprises a mounting member 14, for mounting the support member to the base assembly. The mounting member 14 comprises a spring allowing for vertical movement of the support member 10.
Each roller 12a, 12b is mounted to the support member 10 by a spring mounting member 15a, 15b, allowing for individual vertical movement of each of the rollers 12a, 12b.
[0045] Referring now to Figure 7, a seventh preferred embodiment of the instant invention is shown. A dual caster support comprises a support member 10 and two rollers 12a, 12b, mounted to the support member. The dual caster support further comprises a mounting member 13 for mounting the support member to the base assembly. The mounting member 13 is pivotally mounted to the support member, so that the roller 12a movers up, when the roller 12b moves down. Each roller 12a, 12b is mounted to the support member 10 by a spring mounting member 15a, 15b, allowing for individual vertical movement of each of the rollers 12a, 12b.
[0046] Referring now to Figure 8, a eighth preferred embodiment of the instant invention is shown. A dual caster support comprises a support member 10 and two rollers 12a, 12b, mounted to the support member. The dual caster support further comprises a mounting member 14, for mounting the support member to the base assembly. The mounting member 14 comprises a spring al lowing for vertical movement of the support member 10.
The mounting member 14 is pivotally mounted to the support member, so that the roller 12a movers up, when the roller 12b moves down. Each roller 12a, 12b is mounted to the support member 10 by a spring mounting member 15a, 15b, allowing for individual vertical movement of each of the rollers 12a, 12b.
[0047] Referring now to Figure 9, an ninth preferred embodiment of the instant invention is shown. A dual caster support comprises a support member 10 and two rollers 12a, 12b.
The caster support 10 further comprises a tube member 17, the tube member 17 mounted to the support member 10, a direction of longitudinal extension of the tube member 17 being substantially parallel to a direction of longitudinal extension of the support member. The rollers 12a, 12b are mounted to the tube member 17 by means of mounting pistons 16a, 16b. The tube member 17 and the mounting pistons 16a, 16b form a system of communicating vessels, and are filled with a hydraulic liquid. Thus, when the roller 16a moves up, a hydraulic pressure is exerted on roller 16b, causing roller 16b to move down.
[0048] The principle described in the context of Figure 9 is not restricted to two rollers, but equally applies to a plurality of rollers and a plurality of mounting pistons. 'thus, referring to Figure 10, in a tenth preferred embodiment of the instant invention, a castor support comprises a tube member 17, three rollers 12a, 12b, 12c and three mounting pistons 16a, 16b, 16c.
[0049] An eleventh preferred embodiment of the instant invention is shown in Figure 11.
Three dual caster supports 22a, 22b, 22c support a turntable 6. Each of the dual caster supports 22a, 22a, 22b, 22e comprises two rollers 221x, 222a, 221b, 222b, and 221c, 222c, respectively. Here, the axis of rotation of the two rollers 221a and 222a coincide with a radius of the turntable 6. The same holds for the two rollers 221b, 222b and 221c, 222c. Alternatively, more than three dual castor supports provide support for a turntable 6, each of the dual caster supports comprising at least two rollers, the axes of each pair of rollers coinciding with a radius of the turntable.
[0050] Although the instant invention has been described with respect to specific embodiments thereof, various changes and modifications are easily carried out by those skilled in the art without departing from the scope of the invention.
Therefore, it is intended that the instant invention encompass such changes and modifications as fall within the scope of the appended claims.
Claims (3)
1. A stretch wrapping machine having a base assembly, the base assembly having a turntable and a plurality of dual caster supports, each dual caster support comprising:
a support member supporting two rollers in spaced apart relation for load bearing, the rollers and support member mounted for motion of the roller approximately normal to a plane of said turntable, said rollers for rollingly engaging said turntable;
wherein the motion of the rollers is such that one roller moves down while the other moves up.
a support member supporting two rollers in spaced apart relation for load bearing, the rollers and support member mounted for motion of the roller approximately normal to a plane of said turntable, said rollers for rollingly engaging said turntable;
wherein the motion of the rollers is such that one roller moves down while the other moves up.
2. A stretch wrapping machine according to claim 1, wherein the dual caster support is pivotally mounted to the base assembly, the a mounting point for pivotally mounting being located between the two rollers.
3. A stretch wrapping machine according to claim 1, wherein the dual caster support is movably mounted in a vertical direction, the vertical direction being substantially normal to the plane of the turntable.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2384008 CA2384008A1 (en) | 2002-05-14 | 2002-05-14 | A self adjusting dual caster support system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2384008 CA2384008A1 (en) | 2002-05-14 | 2002-05-14 | A self adjusting dual caster support system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2384008A1 true CA2384008A1 (en) | 2003-11-14 |
Family
ID=29425910
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2384008 Abandoned CA2384008A1 (en) | 2002-05-14 | 2002-05-14 | A self adjusting dual caster support system |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2384008A1 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2009021146A1 (en) * | 2007-08-08 | 2009-02-12 | Samsonite Corporation | Brake system for luggage case |
| US8474224B2 (en) * | 2006-11-30 | 2013-07-02 | Robopac S.P.A. | Turntable apparatus for wrapping machine |
| CN104249853A (en) * | 2014-09-11 | 2014-12-31 | 德清中盈文具用品有限公司 | Automatic cloth applicator for covering foam blocks |
-
2002
- 2002-05-14 CA CA 2384008 patent/CA2384008A1/en not_active Abandoned
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8474224B2 (en) * | 2006-11-30 | 2013-07-02 | Robopac S.P.A. | Turntable apparatus for wrapping machine |
| WO2009021146A1 (en) * | 2007-08-08 | 2009-02-12 | Samsonite Corporation | Brake system for luggage case |
| CN104249853A (en) * | 2014-09-11 | 2014-12-31 | 德清中盈文具用品有限公司 | Automatic cloth applicator for covering foam blocks |
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