Patent Application
20130247299
This disclosure relates to resilient side rails for medical tables.
Tables and beds for supporting patients during medical procedures (e.g., operating room tables) can include various accessories that are used to aid medical staff member during a medical procedure. The tables and beds can include side rails that are configured to temporarily receive one or more accessories.
In an aspect, a side rail for a medical table includes an elongated body having a height and a width that are configured to be received by a medical accessory. The elongated body is formed of a material having a modulus of elasticity that is about 50 gigapascals to about 150 gigapascals and a yield strength that is about 40×107 pascals to about 120×107 pascals.
In another aspect, a medical table system includes a table that is configured to support a patient during a medical procedure and that defines a patient support surface.
The medical table system further includes a side rail disposed along an outer surface of the table. The side rail includes an elongated body having a height and a width that are configured to be received by a medical accessory. The elongated body is formed of a material having a modulus of elasticity that is about 50 gigapascals to about 150 gigapascals and a yield strength that is about 40×107 pascals to about 120×107 pascals.
In a further aspect, a side rail for a medical table includes an elongated body having a height and a width that are configured to be received by a medical accessory. The side rail is configured so that when the side rail is supported along a first, wide side by two support members that are about 300 mm apart and a 500 newton force is applied midway between the support members to a second, opposite side of the side rail, a maximum deflection of the side rail is less than about 5 mm, and when the force is released, the side rail rebounds and substantially no permanent deformation of the side rail occurs.
In an additional aspect, a medical table system includes a table that is configured to support a patient during a medical procedure and that defines a patient support surface. The medical table system further includes a side rail disposed along an outer surface of the table. The side rail includes an elongated body having a height and a width that are configured to be received by a medical accessory. The side rail is secured to the table using a force absorbing member that is configured to permit the side rail to deflect towards the table when energy of about 5 Joules to about 100 Joules is applied to the side rail and to absorb some of the energy applied to the side rail as the side rail deflects towards the table.
Embodiments can include one or more of the following features.
In some embodiments, the height is about 25 mm to about 30 mm (e.g., about 28.6 mm) and the width is about 8 mm to about 10 mm (e.g., about 9.5 mm).
In certain embodiments, the material has a modulus of elasticity that is about 50 gigapascals to about 80 gigapascals and a yield strength that is about 40×107 pascals to about 60×107 pascals.
In some embodiments, the material is 7075-T6 Aluminum.
In certain embodiments, the material has a modulus of elasticity that is about 100 gigapascals to about 130 gigapascals and a yield strength that is about 100×107 pascals to about 120×107 pascals.
In some embodiments, the material is Ti5 Titanium.
In certain embodiments, the side rail further includes a metal plating that substantially covers the elongated body.
In some embodiments, the metal plating includes a nickel based material.
In certain embodiments, the metal plating is an electroless nickel plating that is about 0.025 mm thick.
In some embodiments, when the side rail is supported along a first, wide side by two support members that are about 300 mm apart and a 500 newton force is applied midway between the support members to a second, opposite side of the side rail, a maximum deflection of in the side rail is less than about 5 mm, and when the force is released, the side rail rebounds and substantially no permanent deformation of the side rail occurs.
In certain embodiments, the medical table is an operating room table.
In some embodiments, the maximum deflection is less than about 3.0 mm.
In certain embodiments, the force absorbing member provides a resisting force having a spring force constant that is about 50 N/mm to about 200 N/mm.
In some embodiments, the force absorbing member is a spring.
In certain embodiments, the spring is washer spring.
In some embodiments, the spring force constant of the spring is about 50 N/mm to about 200 N/mm.
In certain embodiments, the energy is about 50 Joules to about 100 Joules.
In some embodiments, the energy is the result of an impact with another object.
Embodiments can include one or more of the following advantages.
The medical table side rails described herein can withstand greater impact forces than certain conventional operating room table side rails without substantially permanently deforming. Such improved impact performance can be achieved by forming the side rails of one or more materials that are flexible (e.g., have a low modulus of elasticity) yet also resistant to permanent deformation (e.g., have a high yield strength).
The medical table side rails described herein can also be lighter than certain conventional operating room table side rails that are approximately the same size. The lower weight side rails can reduce the overall weight of the table making it easier for medical staff members to move the table. This can be particularly beneficial for modular table systems that include removable patent support surface segments.
The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other aspects, features, and advantages will be apparent from the description and drawings, and from the claims.
Medical tables (e.g., operating tables) can include side rails that serve as mounting points for accessories (e.g., surgical accessories). The side rails described herein are made of materials that permit them to withstand impacts (e.g., as a result of the operating tables colliding with other objects) without permanently deforming as a result of the impact.
Referring to
Each support surface segment 104 includes a side rail 106 secured (e.g., fastened) to a side region of the support surface segment 104 to provide a mounting location for accessories, such as a surgical accessory. While
The side rails 106 are fastened to the support surface segment 104 using spacers (e.g., standoffs) such that the side rails 106 are spaced from the support surface segment 104. The spacing from the support surface segment 104 is generally large enough to provide mounting clearance for the accessories to be mounted along the side rail 106. For example, the spacers (e.g., standoffs) can provide a spacing that is about 0.375 inch to about 1 inch from the support surface segments 104.
As shown in
The side rail 106 includes three mounting holes 112. The mounting holes 112 are sized and configured to structurally secure the side rail 106 to one of the support surface segments 104, for example, using fasteners that pass through standoffs and into threaded holes in the support surface segments 104. The mounting holes 112 include recesses (e.g., countersunk recesses) 114 that are sized and configured to receive a portion (e.g., a fastener head) of the fasteners used to secure the side rail 106 to the support surface segment 104. The countersunk recess 114 is typically sized to receive the head of a fastener so that the head lies generally flush with an outer surface 116 of the side rail 106 so that the head of the fastener does not extend beyond the outer surface 116. For example, the mounting holes 112 and the countersunk recesses 114 can be sized and configured to receive and accommodate a flat head cap screw, such as an M10 flat head cap screw.
The mounting holes 112 are spaced apart along the side rail 106 by an inner spacing distance 118. The inner spacing distance is typically small enough to provide adequate structural support limiting the amount that the side rail 106 can flex or deflect during typical use, such as when forces are applied when the accessory 109 is attached to the side rail 106 and supported during use. However, the inner spacing distance 118 is typically large enough so that the side rail 106 is able to flex as a result of impact forces, for example, if an object bumps into the side rail 106 on the operating table 100. Therefore, the desired inner spacing distance 118 can be influenced by the size and shape (e.g., the height and width) of the side rail 106 and the materials from which portions of the side rail 106 (e.g., the elongated body and the plating of the elongated member 110 of the side rail 106) are made. Additionally, the inner spacing distance 118 between the mounting holes 112 can also be determined by regulatory agency specifications or by the manufacturer of the operating table on which the side rail 106 is used. The inner spacing distance 118 is typically about 300 mm or less (e.g., about 50 mm to about 300 mm, about 100 mm to about 250 mm, about 130 mm to about 190 mm).
The mounting holes 112 that are arranged closest to the ends of the side rail 106 are typically spaced apart from the ends of the side rail 106 by an outer spacing distance 120. Like the inner spacing distance 118, the outer spacing distance 120 is typically small enough to provide structural stability for an accessory 109 secured near the end of the side rail 106 during use. However, the outer spacing distance 120 is typically large enough to permit the end of the side rail to flex, for example, when inadvertently bumped into by another piece of equipment. The outer spacing distance 120 is typically about 150 mm or less (e.g., about 35 mm to about 150 mm, about 55 mm to about 90 mm).
The side rail 106 can include accessory retention devices (e.g., an accessory lock) to help prevent accessories from sliding off of the side rail 106, for example, as a result of the table 100 moving. For example, as shown in
As noted above, the elongated member 110 of the side rail 106 is typically formed of an elongated resilient body that is plated with a different (e.g., harder) material than the material of the elongated body. The elongated member 110 provides suitable structural strength to support the various accessories 109 that are secured to the side rail 106 during use, but is also generally able to withstand an impact force (e.g., as a result of an inadvertent collision with another object) without permanently deforming. To withstand impact forces, the material of the elongated body is generally resilient and flexible so that the side rail 106 can deflect under higher, impact loads, for example, side loads applied to the side rail 106. As a result of its flexibility and resilience, the side rail 106 is anticipated to be damaged (e.g., permanently deformed) less frequently, thus reducing required maintenance of the side rails 106 and the table 100 as a whole. For example, side rails made of materials having a modulus of elasticity, which is a measure of a material's stiffness, that is about 50 gigapascals (“GPa”) to about 150 GPa have been shown to provide suitable flexibility in order to permit the side rail to deflect under most expected impact forces.
In combination with the flexibility of the side rail 106 as a result of the lower modulus of elasticity, the material is also selected to have the ability to flex without permanently deforming. Therefore, the material has a high yield strength, which is a measure of the material's ability to resist plastic (e.g., permanent) deformation under stress. For example, side rails made of materials having a yield strength that is about 40×107 pascals (“Pa”) to about 120×107 Pa have been shown to have suitable resistance to permanent deformation.
Materials that possess this combination of a relatively low modulus of elasticity permitting deflection under an applied force and a high yield strength limiting permanent deformation when deflected have been shown to exhibit superior impact performance over side rails made of certain conventional materials, such as stainless steels. Examples of materials that possess combinations of modulus of elasticity and yield strength within the above-referenced ranges include certain aluminums, such as aircraft aluminum (Al 7075-T6) and certain titaniums, such as Ti5 Titanium.
As discussed above, the elongated body of the elongated member 110 of the side rails 106 is typically plated with another harder material. The plated material can provide protection from and resistance to wear and corrosion of the underlying, inner material which can help increase durability of the side rail 106. For applying a suitably plated material to the elongated body that provides adequate wear and corrosion protection, the plated material is typically applied according to one or more regulatory standards, such as ASME plating standards. The elongated body is typically nickel plated. For example, the elongated body can be plated with a 0.025 mm thick electroless nickel medium phosphour plated material.
Deflection Testing
The tested side rail 106 was deflection tested according to EN ISO 19054:2006. Summaries of the test procedures and the corresponding results for each of the deflection tests are provided below in Table 1. Instruments that were used during testing are described below in Table 2.
After completing all the tests, the test side rail 106 was visually examined to verify that it was substantially free of permanent deformation. The test side rail 106 was also checked for flatness on the granite inspection table and showed no sign of deformation.
Impact Testing
The test side rail was also impact tested, according to determine and compare the degree to which the test side rail, which was made of nickel plated 7075-T6 aluminum, and another test rail, which was made of conventional 304 stainless steel but had the same dimensions as the test side rail 106, deform relative to one another when struck with substantially equivalent loads. A summary of the test procedure for the impact test of the test side rail are provided below in Table 3.
Table 4 provides descriptions of respective test samples that were used during impact testing.
After completing each impact for both test side rail samples, the test side rails were examined for permanent deformation. The observed test results of the impact testing are provided below in Table 5. Note that the deformation data results provided in Table 5 were recorded as a change in geometry from one impact to the next impact and not the total observed impact.
When subjected to equivalent impact forces, Sample 2, the stainless steel rail, was shown to deform an average deformation distance per impact that was over twice as much as the deformation of Sample 1, the nickel plated 7075-T6 aluminum rail. This impact testing demonstrated that a side rail made of nickel plated 7075-T6 aluminum can absorb impact forces without permanently deforming better than certain conventional stainless steel side rails.
While the side rails have been described as being fastened in a substantially rigid manner to the standoffs and, therefore, also to the table, other configurations are possible. For example, as shown in
In some embodiments, the spring force constant of each absorbing member 126 is about 50 N/mm to about 200 N/mm. In certain implementations, the side rail 106 equipped with the force absorbing members 126 can withstand energy of about 5 Joules to about 100 Joules (e.g., resulting from an impact force) without experiencing permanent deformation. In some embodiments, the side rail 106 can withstand energy of about 50 Joules to about 100 Joules without experiencing permanent deformation. As an example, the side rail 106 could withstand the impact of a 2 kg mass weight dropped from a height of 1 meter (accelerating at 1 g) without experiencing permanent deformation.
While multiple force absorbing members 126 have been described as being positioned along the side rail, in some embodiments, only one force absorbing member is used. The sole force absorbing member in such embodiments can be positioned on the center standoff.
While the side rail has been described as having a member that defines a generally rectangular cross-sectional shape, other configurations are possible. For example, in some embodiments, the side rail has a cross-sectional shape that is shaped as other polygons (e.g., trapezoids, triangles, pentagons, hexagons, or other polygons), curved shapes (e.g., circles, ellipses, oblong shapes), or other shapes, such as a C-channel, an I-beam, or non-uniform shapes having other curved and/or flat surfaces.
While the side rail has been described as having three mounting holes, the side rail can have more or fewer mounting holes. For example, in some embodiments, the side rail has more than three (e.g., four, five, six, seven, eight, or more) mounting holes. In other embodiments, the side rail has fewer (e.g., two or one) mounting holes.
While the side rail has been described as being attached to the table using fasteners arranged through mounting holes, other attachment devices or techniques can be used. For example, in some embodiments, the side rail is attached to the table using clips, snapping mechanisms, adhesives, welding, or other attachment devices or techniques.
While the side rail has been described as having an accessory lock at one end that can prevent accessories from inadvertently sliding off the side rail, other configurations are possible. For example, in some embodiments, the side rail includes an accessory lock at both ends. In some embodiments, the side rail does not include an accessory lock.
While the table has been described as including three patient support surface segments, other configurations are possible. For example, the table can include fewer (e.g., one or two) patient support segments or more (e.g., four, five, six, seven, or more) patient support surface segments to support the patient in a variety of operating room configurations.
A number of embodiments have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. Accordingly, other embodiments are within the scope of the following claims.
