Retention Assembly For Lift Assembly Of Patient Support Apparatus
A patient support apparatus comprises a base and a support frame. The patient support apparatus also comprises a lift assembly that operates to lift and lower the support frame relative to the base. The lift assembly comprises lift members that extend and collapse to lift and lower the support frame. A timing link is pivotally connected to one of the lift members and pivotally connected to the base. Guides operate to guide movement of the lift members during operation. Retention assemblies are arranged between pivoting components of the lift assembly.
1 . A patient support apparatus comprising:
a base;
a support frame supported by the base;
a patient support deck disposed on the support frame and defining a patient support surface;
a lift assembly operatively arranged between the base and the support frame and configured to effect movement of the support frame relative to the base, the lift assembly including:
a first link and a second link each defining a respective link aperture;
a retention assembly disposed in each of the link apertures to pivotably couple the first link to the second link, the retention assembly comprising:
a pin extending along a pivot axis to a pin end and disposed in each of the link apertures and defining a cross bore;
a retention cap defining a cap aperture extending therethrough, wherein the retention cap is disposed on the pin with the cap aperture aligned with the cross bore; and
a cross-pin disposed in the cross bore and protruding from the cap aperture configured to retain the retention cap to the pin and limit axial movement of the first and second links.
2 . The patient support apparatus of claim 1 , wherein the cross bore is arranged perpendicular to the pivot axis and wherein the pin end is received in the retention cap.
3 . The patient support apparatus of claim 2 , wherein the pin comprises a pin flange opposite the pin end, and wherein the first link and the second link are arranged along the pin between the pin flange and the pin end.
4 . The patient support apparatus of claim 3 , wherein the link aperture in the first link defines a first aperture diameter and the pin flange defines a pin flange diameter, and wherein the pin flange diameter is greater than the first aperture diameter.
5 . The patient support apparatus of claim 1 , wherein the retention cap comprises a retention body extending between a retention end and a retention flange having a diameter larger than the retention end, wherein the retention flange defines a flange face arranged to at least partially limit movement of the second link toward the retention end.
6 . The patient support apparatus of claim 5 , wherein the retention assembly further comprises a washer interposed in contact between the retention flange and an engagement surface defined on the second link adjacent to the link aperture.
7 . The patient support apparatus of claim 5 , wherein the retention cap includes a pair of resilient tangs radially spaced from each other about an axis to define a pair of gap reliefs, wherein the pair of resilient tangs are biased towards each other and in abutment with the pin.
8 . The patient support apparatus of claim 7 , wherein the cap aperture extends through each of the pair of resilient tangs to define two cap openings radially indexed about the pivot axis between the pair of gap reliefs.
9 . The patient support apparatus of claim 7 , wherein each of the pair of resilient tangs comprises a thrust face partially defining the flange face of the retention flange, wherein the thrust face is oriented away from the retention end.
10 . The patient support apparatus of claim 5 , wherein an axis of the cap aperture is spaced from the flange face at a distance at least 1.5× greater than a diameter of the cross-pin.
11 . The patient support apparatus of claim 5 , wherein a diameter of the pin is as least 1.25× greater than a diameter of the cross-pin.
12 . The patient support apparatus of claim 1 , wherein the lift assembly further comprises a bearing element disposed in the link aperture of the second link.
13 . The patient support apparatus of claim 12 , wherein the bearing element is further defined as a plain bearing comprising a bearing flange, and wherein the bearing flange is arranged between the first link and the second link.
14 . The patient support apparatus of claim 13 , wherein the link aperture in the second link defines a second aperture diameter and the bearing flange defines a bearing flange diameter, and wherein the bearing flange diameter is greater than the second aperture diameter.
15 . The patient support apparatus of claim 1 , wherein the cross-pin is further defined as a rivet.
16 . A method of assembling a patient support apparatus including a base and a lift assembly having a first link and a second link each defining a link aperture and supported by the base, the lift assembly further including a retention assembly including a pin defining a cross bore, a retention cap defining a cap aperture, and a rivet, the method comprising:
inserting the pin into the link aperture of the first link and the second link;
arranging the retention cap on an end of the pin;
aligning the cap aperture with the cross bore;
inserting the rivet through the cap aperture and the cross bore in an initial configuration; and
deforming the rivet from the initial configuration to a secured configuration.
17 . The method of claim 16 , wherein the pin extends along a pin axis from a pin flange to a pin end, and wherein the cross bore is arranged proximate to the pin end.
18 . The method of claim 16 , wherein the retention assembly further includes a bearing element having a bearing flange, and further comprising a step of inserting the bearing element in the link aperture of the second link with the bearing flange arranged between the first link and the second link.
19 . The method of claim 16 , wherein the retention cap includes a pair of resilient tangs radially spaced from each other about an axis and biased toward each other into abutment with the pin to at least partially resist relative movement between the retention cap and the pin.
20 . A retention assembly for a pivoting connection of a lift assembly for a patient support apparatus, the retention assembly comprising:
a pin extending along a pivot axis from a pin flange to a pin end and defining a cross bore proximate to the pin end;
a retention cap comprising a retention body extending between a retention flange and a retention end with a cap aperture defined in the retention body, wherein the retention cap is disposed on the pin end with the cap aperture aligned with the cross bore; and
a cross-pin disposed in the cross bore and protruding from the cap aperture configured to retain the retention cap to the pin and limit axial movement of the pivoting connection.
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