Cam-operated latch assembly
10544609 ยท 2020-01-28
Assignee
Inventors
Cpc classification
Y10T292/1077
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
Y10T292/1056
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
Y10T292/108
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
International classification
E05B47/00
FIXED CONSTRUCTIONS
Abstract
A latch assembly is disclosed that has a latch, a locking lever having locked and unlocked positions, and a detent lever having engaged and disengaged positions. The locking lever is configured to secure the latch in the closed position when the locking lever is in the locked position and the detent lever is configured to provide a detent function when the detent lever is in the engaged position. In certain aspects, the latch assembly includes a single motor and cam assembly having three configurations, wherein the locking lever and detent lever are respectively in the unlocked and disengaged positions while in the first configuration, in the unlocked and engaged positions while in the second configuration, and in the locked and engaged positions while in the third configuration.
Claims
1. A latch assembly comprising: a latch having a closed position and an open position; a locking lever having a locked position and an unlocked position, the locking lever configured to secure the latch in the closed position when the locking lever is in the locked position; a detent lever having an engaged position and a disengaged position, the detent lever configured to allow the latch to move between the closed and open positions when the detent lever is in the engaged position; a first cam rotatable about an axis and comprising a first portion that engages against the locking lever to move the locking lever to the unlocked position, and a second portion that is configured to allow the locking lever to move between the locked and unlocked positions; and a second cam rotatable about the axis with the first cam, the second cam comprising a first portion that engages against the detent lever to move the detent lever to the disengaged position, and a second portion configured to allow the detent lever to move between the engaged and disengaged positions.
2. The latch assembly of claim 1, wherein the first portion of the second cam remains aligned with the first portion of the first cam during rotation of the first and second cam.
3. The latch assembly of claim 1, wherein the locking lever is configured to allow the latch to move from the open position to the closed position when the locking lever is in the locked position.
4. The latch assembly of claim 1, wherein the locking lever is configured to allow the latch to freely move between the closed and open positions when the locking lever is in the unlocked position.
5. The latch assembly of claim 1, wherein the detent lever is configured to allow the latch to freely move between the closed and open positions when the detent lever is in the disengaged position.
6. The latch assembly of claim 1, wherein the locking lever and the detent lever are configured to move independently.
7. The latch assembly of claim 6, further comprising an actuator assembly configured to selectably configure the latch assembly to one of three configurations, wherein: the locking lever is in the unlocked position and the detent lever is in the disengaged position in a first configuration; the locking lever is in the unlocked position and the detent lever is allowed to move between the engaged and disengaged positions in a second configuration; and the locking lever is allowed to move between the locked and unlocked positions and the detent lever is allowed to move between the engaged and disengaged positions in a third configuration.
8. The latch assembly of claim 1, further comprising: a locking spring configured to urge the locking lever toward the locked position; and a detent spring configured to urge the detent lever toward the engaged position.
9. The latch assembly of claim 1, further comprising a latch spring configured to urge the latch toward the open position.
10. A method of operating a latch assembly, comprising: rotating a first cam and a second cam about a single axis until a first portion of the first cam engages against a locking lever to move the locking lever to an unlocked position, and a first portion of the second cam engages against a detent lever to move the detent lever to a disengaged position, wherein the first portion of the second cam is rotatably aligned with the first portion of the first cam; and rotating the first cam and the second cam about the single axis until a second portion of the first cam permits the locking lever to move between the unlocked position and a locked position, and a second portion of the second cam permits the detent lever to move between the disengaged position and an engaged position; wherein the locking lever is configured to secure a latch in a closed position when the locking lever is in the locked position, and the detent lever is configured to allow the latch to move between the closed position and an open position when the detent lever is in the engaged position.
11. The method of claim 10, further comprising, permitting the latch to move from the open position to the closed position when the locking lever is in the locked position.
12. The method of claim 10, further comprising, permitting the latch to move between the closed and open positions when the locking lever is in the unlocked position.
13. The method of claim 10, further comprising, permitting the latch to move between the closed and open positions when the detent lever is in the disengaged position.
14. The method of claim 10, further comprising, urging the locking lever toward the locked position using a locking spring.
15. The method of claim 10, further comprising, urging the detent lever toward the engaged position using a detent spring.
16. A latch assembly comprising: a housing; a latch coupled to the housing, the latch comprising a first position and a second position; a locking lever coupled to the housing, the locking lever comprising a locked position and an unlocked position, the locking lever configured to secure the latch in the first position when the locking lever is in the locked position; a detent lever coupled to the housing, the detent lever comprising an engaged position and a disengaged position, the detent lever configured to allow the latch to move between the first and second positions when the detent lever is in the engaged position; a cam assembly comprising a first cam and a second cam rotatably aligned about a single axis, the cam assembly rotatable to a first position, a second position, and a third position, the cam assembly configured to: contact the locking lever with a first cam to move the locking lever to the unlocked position and contact the detent lever with a second cam to move the detent lever to the disengaged position when the cam assembly is in the first position; contact the locking lever to move the locking lever to the unlocked position and allow the detent lever to move between the engaged and disengaged positions when the cam assembly is in the second position; and allow the locking lever to move between the locked and unlocked positions and allow the detent lever to move between the engaged and disengaged positions when the cam assembly is in the third position; and a single motor coupled between the housing and the cam assembly, the motor configured to selectably move the cam assembly to one of the group of the first position, the second position, and the third position.
17. The latch assembly of claim 16, wherein a latch spring is coupled to the latch, the latch spring configured to urge the latch toward the second position.
18. The latch assembly of claim 16, wherein a locking spring is coupled to the locking lever, the locking spring configured to urge the locking lever toward the locked position.
19. The latch assembly of claim 16, wherein a detent spring is coupled to the detent lever, the detent spring configured to urge the detent lever toward the engaged position.
20. The latch assembly of claim 1, wherein the first cam and the second cam are longitudinally aligned along the axis.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The accompanying drawings, which are included to provide further understanding and are incorporated in and constitute a part of this specification, illustrate disclosed embodiments and together with the description serve to explain the principles of the disclosed embodiments. In the drawings:
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DETAILED DESCRIPTION
(14) The following description discloses embodiments of a latch that provides a locking feature that secures a moving element, such as a drawer, in a first position or allows the drawer to move to a second position. The latch also includes the ability to provide a detent function that either holds the drawer in the first position or allows the drawer to move freely between the first and second positions. In certain embodiments, the actuation of both the locking feature and the detent feature are accomplished by a single actuator assembly, such as a motor turning a cam assembly.
(15) While this disclosure explains certain features and aspects of the latch in terms of an ADM used in a hospital environment, it will be apparent to those of skill in the art that embodiments of the disclosed latch may be used in other environments and for other purposes. The detailed description set forth below is intended as a description of various configurations of the subject technology and is not intended to represent the only configurations in which the subject technology may be practiced. The appended drawings are incorporated herein and constitute a part of the detailed description. The detailed description includes specific details for the purpose of providing a thorough understanding of the subject technology. However, it will be apparent to those skilled in the art that the subject technology may be practiced without these specific details. In some instances, well-known structures and components are shown in block diagram form in order to avoid obscuring the concepts of the subject technology. Like components are labeled with identical element numbers for ease of understanding.
(16) As used within this disclosure, the term latch is defined as a component or assembly either coupled to one of a relatively stationary element or a moving element and configured to engage a corresponding feature of the other of the moving element or the stationary element. When the latch is moved to a first position, the latch secures the feature such that the moving element is restrained from movement relative to the stationary element. A latch may have a second position that allows the feature to engage the latch as the moving element moves with respect to the stationary element. The motion of the latch between the first and second positions may be linear or rotational.
(17) As used within this disclosure, the terms lock and locked are defined as remaining in a single secured position under the application of forces that are less than the amount of force or torque that will cause damage or breakage of any element associated with the locking function. A device may be considered to be locked while a moving element is not in the secured position, for example when a drawer is still open, if the device is configured to capture and retain the moving element when it first moves to the secured position, for example when the drawer is fully closed.
(18) As used within this disclosure, the term detent is defined as a resistance to moving a moving element away from a particular position until at least a certain amount of force or torque is applied to the moving element, whereupon the moving element is permitted to move away from that particular position. The certain amount of force is less than the amount of force or torque that will cause damage or breakage to any element associated with the detent function. The certain amount of force is greater than an amount of force that may be generated by activities not intended to move the moving element, for example bumping a chassis of an ADM in which the moving element is mounted.
(19) As used within this disclosure, the term spring is defined as an elastic element that applies a force in proportion to the deformation of the element. Non-limiting examples include coils of metal wire, plastic cantilevers, and compressible blocks of material.
(20) As used within this disclosure, the term motor is defined as a device that causes motion in response to the provision of electrical energy. Non-limiting examples of motors include a linear solenoid and a rotational drive that may include one or more of conductive coils and permanent magnets. A motor may also include active or passive elements that control or modulate the provided electrical energy, for example switches, filters, and processors.
(21) As used within this disclosure, the term freely move is defined as moving without resistance, beyond friction between elements that are moving with respect to each other, within a defined range of motion.
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(23) The latch assembly 10 also includes a locking lever 40 and a detent lever 30 that engage various features of the latch 16. Functions of the locking lever 40 are described in greater detail with respect to
(24) This embodiment of the latch assembly 10 includes a latch spring 68 configured to urge the latch 16 towards the second position, a detent spring 64 configured to urge the detent lever 30 toward the engaged position, and a locking spring 66 configured to urge the locking lever 40 toward the locked position.
(25) The latch assembly 10 also includes an actuator assembly 60 configured to selectably configure the latch assembly 10 to one of three configurations. In the first configuration, the locking lever 40 is in the unlocked position and the detent lever 30 is in the disengaged position. In the second configuration, the locking lever 40 is in the unlocked position and the detent lever 30 is allowed to move between the engaged and disengaged positions. In the third configuration, the locking lever 40 is allowed to move between the locked and unlocked positions and the detent lever 30 is allowed to move between the engaged and disengaged positions. The latch assembly 10 is shown in the third configuration in
(26) The actuator assembly 60 includes a motor 62, a gear train 64, and a cam assembly 50. The cam assembly 50 is described in greater detail with respect to
(27) In this embodiment, the latch assembly 10 also includes a switch 62 that is configured to detect whether the latch 16 is in the first position. In this example, an arm 62A rides against a surface of cam 20 which is configured such that the switch 62 is closed when the latch 16 is rotated into the first position and open when the latch 16 is not in the first position.
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(46) In the unlocked/latched/closed configuration of
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(51) The disclosed examples of a single-actuator latch assembly provide a robust mechanism that provides both a locking capability and a latching capability at a reduced cost with increased reliability. When selectively moved to one of the three disclosed configurations, the latch assembly can (1) lock a moving element in a closed position and, if the moving element is open, capture the moving element when it returns to the closed position, (2) unlock the moving element and allow it to be opened and closed while providing a detent feature, or (3) unlock the moving element and allow it to freely move between and open and closed position. The use of a single actuator to selectively move the latch assembly to one of the three disclosed configurations improves the reliability of the latch assembly by eliminating points of failure, such as a second actuator, and reduces the cost of the complete system by eliminating the need for a lock assembly and a separate detent assembly but also the wiring and mechanical elements associated with the second assembly.
(52) While the disclosed embodiments of the latch are shown with the latch assembly mounted on the stationary element and engage an engagement feature on a moving element, other embodiments of the latch include mounting of the latch assembly on the moving element and provision of the engagement feature on the stationary element. In addition, elements that are shown as single assemblies, for example the cam assembly 50 and the second cam 20 of latch 16, may be provided as separate elements in certain embodiments. Additional elements, for example a spring configured to push the drawer 90 outward when the latch 16 is released, may be provided in certain embodiments.
(53) The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but is to be accorded the full scope consistent with the language claims.
(54) Reference to an element in the singular is not intended to mean one and only one unless specifically so stated, but rather one or more. Use of the articles a and an is to be interpreted as equivalent to the phrase at least one. Unless specifically stated otherwise, the term some refers to one or more.
(55) Pronouns in the masculine (e.g., his) include the feminine and neuter gender (e.g., her and its) and vice versa. All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed under the provisions of 35 U.S.C. 112, sixth paragraph, unless the element is expressly recited using the phrase means for or, in the case of a method claim, the element is recited using the phrase operation for.
(56) Although embodiments of the present disclosure have been described and illustrated in detail, it is to be clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, the scope of the present invention being limited only by the terms of the appended claims.