Method and apparatus for reducing force transmitted from a base structure to a supported structure

A method and apparatus are disclosed for reducing transmission of force from a base structure to a supported structure. The method includes mounting a plurality of dampers between the base structure and the supported structure. Each damper includes a single damping element having at least two contact arms affixed to either the base structure or the supported structure. Damping of forces is achieved by each damper in multiple orthogonal directions. The base structure is mounted to a transportation vehicle. The supported structure includes equipment mounted on a floating platform.

BACKGROUND OF THE INVENTION

Certain embodiments of the present invention relate to reducing forces transmitted from one structure to another. More particularly, certain embodiments of the present invention relate to reducing forces transmitted to a diagnostic medical system during shipment.

Diagnostic medical systems, such as a diagnostic X-ray system having a large C-arm, are complex, large, heavy, and expensive systems that need to be protected from damage due to shock and vibration during shipment. Units are typically shipped all around the world in vehicles experiencing various road conditions.

Various packaging systems and methods have been used in shipping medical systems. For example, one method includes mounting the medical system directly onto a wooden base with the chassis of the system elevated and supported on wooden strips. Another method includes sandwiching expanded polyurethane (EP) foam between two layers of plywood and mounting the system on the top layer. The two methods typically do not provide the required isolation from shock and vibration. Other methods include using a high-density polyethylene (HDPE) pallet with the system mounted on the pallet. The tooling cost and per unit production cost of the HDPE pallet often prove to be prohibitive, however.

Some methods include using relatively sophisticated isolators incorporated into relatively sophisticated configurations. For example, a method described in U.S. Pat. No. 5,808,866 to Porter describes having isolators mounted between a case and a card cage within the case. U.S. Pat. No. 5,149,066 Snaith, et al. describes an isolator having a plurality of arched elements arranged circumferentially about an axis between two structures. U.S. Pat. No. 4,269,400 to Jensen describes an isolator having a plurality of concentrically-arranged, nested, bell-shaped components stacked in parallel about a common axis. U.S. Pat. No. 4,783,038 to Gilbert, et al. describes an isolator with flexural support element pairs being located and offset in planes at acute angles from the horizontal defined by a base means.

The methods and systems described above tend to be complex, expensive, and/or inadequate for reducing shock and vibration. For example, the isolators described above have multiple damping elements arranged in complex configurations.

A need exists for a simple damper with a single damping element capable of providing resistance to shock and vibration forces in multiple orthogonal spatial directions. A need also exists for a relatively simple packaging system that uses a plurality of the simple dampers in a simple configuration.

SUMMARY OF INVENTION

An embodiment of the present invention provides for a packaging system for reducing transmission of force from a base platform to a floating platform by employing a plurality of dampers mounted between the base platform and the floating platform. The dampers each comprise a single damping element having at least two contact arms affixed to either the base platform or the floating platform. A plurality of side panels attach to the base platform to enclose equipment that is mounted to the floating platform.

Apparatus is provided for reducing transmission of force from a base structure to a supported structure. The apparatus comprises a single damping element having at least two contact arms affixed to either the base structure or the supported structure. An affixing base plate is mounted between the damping element and the base structure and an affixing offset plate is mounted between the damping element and the supported structure. The single damping element provides resistance to force in multiple orthogonal spatial directions.

A method is also provided for reducing transmission of force from a base structure to a supported structure. The method includes mounting a plurality of dampers between the base structure and the supported structure. The dampers each include a single damping element having at least two contact arms affixed to either the base structure or the supported structure. The base structure is mounted to a transportation vehicle. The supported structure includes a diagnostic medical system mounted on a floating platform.

Certain embodiments of the present invention afford an approach to providing resistance to shock and vibration forces in multiple orthogonal spatial directions using simple dampers each having a single damping element. Certain embodiments also provide for a relatively simple packaging system that uses a plurality of the simple dampers in a simple configuration.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1is an isometric drawing of a damper having a single damping element in accordance with an embodiment of the present invention.

FIG. 2is a top perspective view of a double-X damping element in accordance with an embodiment of the present invention.

FIG. 3illustrates the method of mounting a diagnostic medical system on a floating platform by employing a plurality of the dampers ofFIG. 1in accordance with an embodiment of the present invention.

FIGS. 4a,4b, and4cillustrate several views of a simple configuration of a plurality of the dampers ofFIG. 1arranged between a base platform and a floating platform in accordance with an embodiment of the present invention.

FIG. 5illustrates a packaging system employing a plurality of the dampers ofFIG. 1in accordance with an embodiment of the present invention.

The foregoing summary, as well as the following detailed description of certain embodiments of the present invention, will be better understood when read in conjunction with the appended drawings. It should be understood, however, that the present invention is not limited to the arrangements and instrumentality shown in the attached drawings.

DETAILED DESCRIPTION

FIG. 1is an isometric view of a damper10showing certain elements of the damper10in accordance with one embodiment of the present invention. The damper10comprises a base plate30, an offset plate20, and a single damping element40. The single damping element40is a single molded piece of rubber having four contact arms50,60,70,80forming a three-dimensional X shape in one embodiment of the present invention.

The two lower contact arms70and80connect to the base plate30and the two upper contact arms50and60connect to the offset plate20. The base plate30and the offset plate20are made of steel in one embodiment of the present invention. A chemical bonding process may be used to bond the contact arms50–80of the rubber damping element40to the steel base plate30and steel offset plate20.

The base plate30and the offset plate20each have a through-hole90and100, respectively. The through-holes90and100may be used to bolt the damper10between a base platform and a floating platform of a packaging system. When mounted between two platforms, the damper10reduces transmission of shock and vibration forces in all three orthogonal spatial directions x, y, and z as shown inFIG. 1.

The rubber contact arms50–80of the damping element40allow the transmission of force to be reduced from the base plate30to the offset plate20by flexing when force is applied to the base plate from an external source. The X-shape and the rubber material of the damping element40provide flexure between the base plate30and offset plate20in all three spatial directions x, y, and z. The density and thickness of the rubber material of the damping element40determine the amount of flexure (resistance to force) provided by a single damper10.

Some typical specifications that are met by the X-damper design are shown in Table 1. The packaging system is designed such that the permissible shock values are limited within that shown in Table 1. Shock values that exceed the specifications are damped by the packaging system. The specifications in Table 1 are representative of the shock forces permissible, as per the GMTC (Global Mechanical Technology Center) standards, by the equipment within the packaging system when on a truck making a 2000 km trip.

More specifically, the dimensions of one embodiment of the X-shaped damper10are set based on shipping a medical diagnostic X-ray system with a large C-arm and meeting the specifications of Table 1. The height of the damper along the z direction, including the base plate30and offset plate20, is 100 millimeters, the length along the x direction is 110 millimeters, and the width along the y direction is 70 millimeters. The thickness of the steel base plate30and offset plate20are each 10 millimeters. The rubber material of the single damper is as follows: Specification of the rubber:

Material: Natural Rubber (No synthetic Variables, Re- Cyclable)Service Temp:70° C.Hardness:80 Shore ASpecific Gravity:0.83Tensile Strength:22 MP
Other materials may be used for the damping element40to achieve various levels of flexure and, therefore, damping for various combinations of density and thickness of the other materials. Materials and dimensions of the damping element may be customized for different equipment having various weights and centers of gravity.

The fact that the damping element40is a single molded piece having a relatively simple shape makes it easy to manufacture and keeps molding and per unit costs down. Of course, other shapes may be configured for the single damping element. For example,FIG. 2shows a top view of a double-X configuration, having one X crossing orthogonally through another X, manufactured as a single piece. As a result, four contact arms51,52,61, and62extend from above the center intersection55of the double-X and four contact arms (not shown) extend from below the center intersection55of the double-X. The double-X configuration may potentially allow more similar damping to be provided along the x and y directions.

FIG. 3illustrates the method of mounting a diagnostic medical system on a floating platform by employing a plurality of the dampers ofFIG. 1in accordance with an embodiment of the present invention. A diagnostic medical system140is mounted on top of a floating platform110. A plurality of X-shaped dampers130–133are shown being mounted between the floating platform110and the base platform120. The dampers are typically bolted to the floating platform and base platform. Various attachment methods may be used to secure the system140to the floating platform110, such as employing brackets and mounting screws, depending on the configuration of the system140.

FIGS. 4a,4b, and4cshow various views of a typical damper configuration between a base platform120and a floating platform110. In this example, eight dampers130–137are configured in a rectangular, symmetrical pattern. The base plates of the dampers are bolted to the base platform and the offset plates of the dampers are bolted to the floating platform. Any forces that are experienced by the base platform are damped by the dampers and, therefore, the floating platform experiences less force than that experienced by the base platform. As a result, equipment that is mounted to the floating platform is protected from the full force applied to the base platform.

FIG. 5is a three-dimensional view of a packaging system200, illustrating how a diagnostic medical system140may be packaged using the damper concept. The medical system140is mounted to the floating platform110. The dampers (134–137are shown in this view) are mounted between the floating platform110and the base platform120. Side panels150are mounted around the base platform120to enclose the medical system140on the floating platform110. When the medical system140is shipped, the base platform120may be mounted to the floor of a shipping vehicle such as a truck. In one embodiment of the present invention, the specifications of Table 1 are met. When the base platform120experiences the g-forces expected on a 2000 Km road trip, the diagnostic medical X-ray system140with its large C-arm141may not experience shock values that exceed the specification of Table 1.

As a comparison to other methods of damping, a 70 km road test was performed for three designs. The first design uses the expanded polyurethane (EP) foam, the second design uses a HDPE pallet, and the third design uses the X-shaped dampers. During the 70 km road test, the number of force events over 1.5 g experienced by the diagnostic medical system were measured. The EP foam design experienced 16 events, the HDPE design experienced 7 events, and the X-shaped damper design experienced zero events clearly illustrating the superior damping performance of the X-shaped damper design.

As an alternative, other configurations of dampers may be used depending on the weight and center of gravity of the equipment to be shipped. For example, a circular configuration of dampers may provide better overall damping for equipment where the weight is distributed mostly along the outer perimeter of the equipment. As a further alternative, dampers of differing designs may be employed in a single shipping configuration. For example, in the rectangular configuration ofFIG. 4a, dampers130,131,134, and135may be X-shaped, and dampers132,133,136, and137may be double-X shaped. As a result, the damping of forces experienced by the front half of the packaging system (corresponding to dampers132,133,136, and137) may be more uniform in the x and y-directions. The damping of forces experienced by the back half of the packaging system (corresponding to dampers130,131,134, and135) may be greater in the x-direction and less in the y-direction. Such a configuration may be desirable for certain types of equipment to be shipped.

In summary, the advantages and features include, among others, providing a simple damper with a single damping element capable of providing resistance to forces in multiple orthogonal spatial directions and a relatively simple packaging system that uses a plurality of the simple dampers in a simple, low cost configuration.