US 4,731,889 AGranted

Safety latch for a tilting bed

AssigneeKabushiki Kaisha Toshiba

InventorNaobumi Ishikawa

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Abstract

This invention provides a highly reliable safety device having a high fail-safe feature, which comprises a sector gear rotatably supported on a support base, a bed section supported on the sector gear and tiltable to a predetermined diagnostic angle anywhere from a horizontal position to a standing position of a patient, an off-normal rotation control means such as a limit switch to detect that the rotation of the sector gear relative to the support base exceeds the range of a limit rotation angle and to control its rotation, a hook member provided in a side surface position of the sector gear corresponding to the limit rotation angle beyond the off-normal rotation angle, a hook holding mechanism journaled in a side surface position of said support base which faces the sector gear, and adapted to engage with the hook member to restrict and prevent any further rotation of the sector gear, and whereby the bed section is positively restricted against any further tilting beyond its limit rotation angle, immediately informing an operator of an off-normal state of the safety device, preventing a possible accident on the bed section and the patient.

Claims7

Dependent claims

A tilting bed, comprising:

a. a support base having a mounting surface portion;
b. a sector gear rotatably supported on said support base and having a side surface facing said mounting surface portion of said support base;
c. a bed section supported on said sector gear and selectively tiltable to a desired diagnostic position by rotation of said sector gear to a desired rotation angle relative to said supoprt base, said desired rotation angle being within a preselected normal rotation angle range;
d. drive means for rotating said sector gear;
e. off-normal rotation control means for stopping operation of said drive means when said sector gear is rotated to a preselected off-normal angle, said off-normal rotation angle being beyond said normal rotation angle range by a preselected first marginal angle;
and
f. safety stop means for holding said sector gear when said sector gear is rotated to a preselected limit angle, said limit angle being beyond said normal rotation angle range by a preselected second marginal angle greater than said first marginal angle, said safety stop means including:
a hook member mounted on said side surface of said sector gear and having a hook portion, and
hook holding means for engaging said hook member and holding said sector gear when said sector gear is rotated beyond said normal rotation angle range to said limit angle, said hook holding means including a pair of engaging hooks mounted on said mounting surface portion of said support base in a spaced-apart relation and rotatable only inwardly toward each other, whereby, when said sector gear is rotated beyond said normal rotation angle range and said off-normal rotation angle to said limit angle, said hook member pushes aside one of said engaging hooks to cause said one of said engaging hooks to be inwardly rotated toward the other of said engaging hooks, and then said hook member is positioned and held between said engaging hooks.

6 more elements

A tilting bed, comprising:

a. a support base having a mounting surface portion;
b. a sector gear rotatably supported on said support base and having a side surface facing said mounting surface portion of said support base;
c. a bed section supported on said sector gear and selectively tiltable to a desired diagnostic position by rotation of said sector gear to a desired rotation angle relative to said support base, said desired rotation angle being within a preselected normal rotation angle range;
d. drive means for rotating said sector gear;
e. off-normal rotation control means for stopping operation of said drive means when said sector gear is rotated to a preselected off-normal rotation angle, said off-normal rotation angle being beyond said normal rotation angle range by a preselected first marginal angle;
and
f. safety stop means for holding said sector gear when said sector gear is rotated to a preselected limit angle, said limit angle being beyond said normal rotation angle range by a preselected second marginal angle greater than said first marginal angle, said safety stop means including:
a hook member mounted on said side surface of said sector gear, and
hook holding means for engaging said hook member and holding said sector gear when said sector gear is rotated beyond said normal rotation angle range to said limit angle, said hook holding means including a pair of engaging hooks pivotally mounted on said mounting surface portion of said support base in a spaced-apart relation and a stopper fixed to said mounting surface portion of said support base between said engaging hooks, each of said engaging hooks being rotatable only in one direction, whereby, when said sector gear rotates beyond said normal rotation angle range and said off-normal angle to said limit angle, said hook member pushes aside one of said engaging hooks to cause said one of said engaging hooks to be rotated in said one direction, and then said hook member is positioned and held between said one engaging hook and said stopper.

6 more elements

Dependencies are inferred from the claim text.