EP0640738A1 - Door operating mechanism - Google Patents

Abstract

A door operating mechanism, preferably a door operating mechanism for cabinets, comprising a vertical pivot shaft (2) equipped with eccentric pins (5) at opposite ends thereof to cooperate with keeper members (3) characterized by, that the vertical pivot shaft (2) is fixed by clamps (4) secured to the door at certain distances from the bottom and the top of the cabinet doors thereby permitting the elastic force occuring in the vertical pivot shaft (2) to be employed to close the door tightly against the sealing gasket on the cabinet.

Description

• The present invention relates to improvements in door operating mechanisms, and especially door operating mechanisms for cabinets, comprising a vertical elastic pivot shaft equipped with eccentric pins at opposite ends thereof to cooperate with keeper members. A number of clamps which are secured to the door at a certain distance from the top and the bottom accomodate the vertical shaft. The fixing of the shaft by means of a number of clamps provides the vertical shaft with an elastic effect thereby ensuring optimal tightening of the door.
BACKGROUND OF THE INVENTION
• Today it is known to use door operating mechanisms, especially for double hinged doors for refrigerator cars, where the operating mechanism comprises one vertical shaft with pins cooperating with keeper members at the top and at the bottom. The handle is horizontally secured to one door.
• In principle said door operating mechanism comprises two eccentric pins which cooperate with keeper members at the top and at the bottom. Said door operating mechanism is manufactured from up to approximately 30 individual components.
• See for exampel according to US Patent no. 1 925 234, US Patent no. 1 952 112, US Patent no. 1 956 679, and US Patent no. 2 297 007.
• None of the above mentioned door operating mechanisms are actuated by the elastic force occuring in the vertical shaft when secured to a number of clamps on the door.
OBJECT OF THE INVENTION
• It is an object of the present invention to provide a door operating mechanism which secures optimal tightening of cabinet doors, e.g. doors for laboratory cabinets, experimental animal cabinets, refrigerator cars, refrigerators, deep freezers, containers, industrial washing machines, and industrial automatic dishwashers.
• Another object of the present invention is to provide a door operating mechanism consisting of as few individual parts as possible, and thereby reducing manufacturing costs for materials, moulding tools, mounting, etc. to a minimum.
• A further object of the present invention is to provide a door operating mechanism which can be easily cleaned by comprising only simple components in a limited number.
DESCRIPTION OF THE INVENTION
• The objects of the invention are achieved by providing a door operating mechanism, and preferably a door operating mechanism comprising a vertical elastic pivot shaft equipped with two eccentric pins, as follows:
• A door operating mechanism, preferably a door operating mechanism for cabinets, comprising a vertical pivot shaft (2) equipped with eccentric pins (5) at opposite ends thereof to cooperate with keeper members (3) characterized by, that the vertical pivot shaft (2) is fixed by one or more clamps (4) secured to the door at certain distances from the bottom and the top of the cabinet doors thereby permitting the elastic force occuring in the vertical pivot shaft (2) to be employed to close the door tightly against the sealing gasket on the cabinet.
• A door operating mechanism as above characterized by, that the door operating mechanism includes the following individual components: a vertical elastic pivot shaft including handle and eccentric pins (1); keeper members (3) at the top and at the bottom; as well as a number of clamps (4) secured to the cabinet door for fixing of the vertical shaft (2).
• A door operating mechanism as above characterized by, that the shaft (2) is fixed by one or more clamps (4).
• A door operating mechanism as above characterized by, that the keeper members (3) are designed to operate two vertical shafts (2) equipped with eccentric pins (5) simultaneously, and that the keeper member is symmetrical, and that the same keeper member is applied at both the bottom and the top of the cabinet.
• A door operating mechanism as above characterized by, that the keeper member (3) is designed to operate as a fender protecting the cabinet and the handle during for example transportation.
• Application of a door operating mechanism as above for cabinet doors for e.g. laboratory cabinets, experimental animal cabinets, refrigerator cars, containers, refrigerators, deep freezers, industrial washing machines, and industrial automatic dishwashers.
• The invention has been developed with the main object of ensuring optimal tightening of the cabinet doors. This has been achieved by using the elastic effect occuring in the vertical shaft (2) when fixed in a number of clamps on the cabinet door.
• The present invention is especially suitable for a ventilated cabinet with highly efficient filters mounted on the air in- and outlet. As such cabinets especially are used to house experimental animals in connection with various research projects, it is of the utmost importance that the cabinet doors are tight in closed position. This prevents non-filtered air from entering through leaks e.g. where the doors meet the cabinet. The consequence of non-filtered air entering the cabinet may result in unreliable, non-reproducible, and incomparable test results.
• Furthermore the personnel by the invention is protected from possible allergens from the air in the cabinet.
• The vertical shaft of the presently known door operating mechanisms is fixed only at the top and at the bottom of the cabinet. The natural consequence being that the door only closes tightly in those points and a slightly concave bending of the door arises which permits an undesirable flow of air to enter into the cabinet.
• By fixing the shaft by a number of clamps mounted at a certain distance from the top and the bottom, the bending of the door against the sealing gasket on the cabinet frame is reduced to a minimum. Furthermore, this ensures that the pivot shaft of the door operating mechanism produces a uniform and constant pressure in closed position, thus obtaining optimal tightness between the edges of the door frame and the sealing gasket.
• A constant and equally distributed force from the pressure of the sealing gasket is applied to the door frame (the working force to be applied to the sealing gasket in question according to the manufacturer). The equally distributed force occuring from the sealing gasket and one single force at each end of half the horizontal sealing force from the profile at the top and at the bottom, act on the vertical closing profile of the door frame.
• Furthermore, a number of individual opposite forces corresponding to the number of clamps act on the closing profile.
• The pivot shaft of the door operating mechanism exerts a pressure on the door frame through a number of clamps, with an opposite force corresponding to the pressure of the sealing gasket. This force occurs when the keeper members at each end make the pivot shaft bend at the clamps.
• To fix the dimensions of the pivot shaft of the door operating mechanism and the keeper member, the number and the position of the clamps are calculated so that the bending of the closing profile of the door is reduced to a minimum.
• When these factors are known, the necessary bending of the pivot shaft is calculated to obtain the optimal pressure against the sealing gasket in closed position.
• The keeper members are so designed that said bending is maintained when the door is closed resulting in a constant elastic force being exerted on the door by the pivot shaft.
• An example of such calculation using two clamps is as follows.
Definitions:

P1

: Equally distributed force from the sealing gasket

P2

: Single force from the horizontal profile at each end of the door

P3

: The total necessary closing pressure

E

: The modulus of elasticity of the profile/pivotshaft

I

: The moment of inertia of the profile/pivot shaft

l

: The distance between the symmetrically fixed clamps

c

: The distance from the end of the profile to the clamp

L

: l + 2 * c

ume

: Bending at the middle from the single force

uee

: Bending at the ends from the single force

umj

: Bending at the middle from the equally distributed force

uej

: Bending at the ends from the equally distributed

umin

: Minimum total bending of the the vertical profile

uaf

: Bending of cabinet profile

uind

: Bending of pivot shaft




$$\text{x :=}\frac{\text{<figure-callout id="2" label="L" filenames="imgf0001.png" state="{{state}}">L</figure-callout>}}{\text{2}}\text{□}$$


• The distance c is optimized for minimum bending, "uaf" indicates a possible bending of the cabinet profile. $$\text{umin := ume + umj - (uee + uej) - uaf □}$$

  
• When c is known, the necessary bending of the pivot shaft is calculated.

  
• In one form of embodiment of the invention the pivot shaft is constituted of for example a crankshaft. Preferably the pivot shaft forms part of a body (1) defined by two bars of which one is the vertical elastic pivot shaft (2) and the other is a handle (7). These bars are preferably fully welded to the top and bottom end surfaces (6). Eccentric pins are preferably welded to the opposite sides of said end surfaces, for engagement with keeper members (3) secured to the top and bottom of the cabinet. The body follows the full heigth of the cabinet.
• In another form of embodiment of the invention the keeper member is symmetrical thereby permitting the same keeper member to be used at both the top and the bottom of the cabinet. This is preferable when using double hinged doors.
• Furthermore, the keeper member is provided with a fender effect protecting the handles from bumps, etc. for example during transportation.
• Said fender effect is provided by making the keeper member sufficiently large to constitute the outermost point of the cabinet at both the top and the bottom.
• Consequently, a complete door operating mechanism comprising as few components as possible, thereby reducing the manufacturing costs for materials, moulding tools, etc. to a minimum, has been achieved.
• Furthermore, said door operating mechanism is very simple to handle in that the handle (7) is provided by a vertical bar which follows the height of the cabinet.
• Grasp the handle with one hand, then turn it approximately 80 degrees and pull it outwardly.
• Furthermore, this simple construction makes the door operating mechanism easy to clean in that all dirt traps are eliminated.
• For further illustration of the invention reference is made to the enclosed figure and with reference to the numbers appearing in the description above and the appended claims these corresponds to the numbers appearing on the figure enclosed herewith, and mean:
• 1 Vertical elastic pivot shaft including handle and eccentric pins
• 2 Vertical elastic pivot shaft
• 3 Keeper member
• 4 Clamps
• 5 Eccentric pins
• 6 End surfaces
• 7 Handle

Claims (6)

1. A door operating mechanism, preferably a door operating mechanism for cabinets, comprising a vertical pivot shaft (2) equipped with eccentric pins (5) at opposite ends thereof to cooperate with keeper members (3) characterized by, that the vertical pivot shaft (2) is fixed by clamps (4) secured to the door at certain distances from the bottom and the top of the cabinet doors thereby permitting the elastic force occuring in the vertical pivot shaft (2) to be employed to close the door tightly against the sealing gasket on the cabinet.
2. A door operating mechanism as in claim 1 characterized by, that the door operating mechanism includes the following individual components: a vertical elastic pivot shaft including handle and eccentric pins (1); keeper members (3) at top and bottom; as well as a number of clamps (4) secured to the cabinet door for fixing of the vertical shaft (2).
3. A door operating mechanism as in claim 1 characterized by, that the shaft (2) is fixed by one or more clamps (4).
4. A door operating mechanism as in claim 1 characterized by, that the keeper members (3) are designed to operate two vertical shafts (2) equipped with eccentric pins (5) simultaneously, and that the keeper member is symmetrical, and that the same keeper member is applied in both the bottom and the top of the cabinet.
5. A door operating mechanism as in claim 1 characterized by, that the keeper member (3) is designed to operate as a fender protecting the cabinet and the handle during for example transportation.
6. Application of a door operating mechanism as in claim 1 for cabinet doors for e.g. laboratory cabinets, experimental animal cabinets, refrigerator cars, containers, refrigerators, deep freezers, industrial washing machines and industrial automatic dishwashers.

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