US3703147A - Locking mechanism for vertically adjustable drawing boards - Google Patents
Locking mechanism for vertically adjustable drawing boards Download PDFInfo
- Publication number
- US3703147A US3703147A US137793A US3703147DA US3703147A US 3703147 A US3703147 A US 3703147A US 137793 A US137793 A US 137793A US 3703147D A US3703147D A US 3703147DA US 3703147 A US3703147 A US 3703147A
- Authority
- US
- United States
- Prior art keywords
- levers
- link
- lever
- locking mechanism
- guide member
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
-
- A—HUMAN NECESSITIES
- A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
- A47B—TABLES; DESKS; OFFICE FURNITURE; CABINETS; DRAWERS; GENERAL DETAILS OF FURNITURE
- A47B27/00—Drawing desks or tables; Carriers for drawing-boards
- A47B27/18—Locking means, e.g. for locking inclination of board
Definitions
- a parallel motion guiding mechanism supporting a drawing board and including two opposite levers is provided with a link between the levers pivotally connected with one of the levers and connected with the other lever for rotational movement and displacement longitudinally of the link.
- a locking mechanism is provided to optionally lock the link to said other lever in order to prevent a change of the mutual spacing of the levers and thereby to prevent movement of the parallel motion guiding mechanism.
- the main object of the present invention is to remove this drawback.
- Drawing tables of the type described now commonly used are generally provided with a counterbalancing mechanism.
- a counterbalancing mechanism is adapted to retain the drawing board in the vertically adjusted position which necessitates a very accurately calculated construction in view of the fact that the inclination of the drawing board effects the position of the center of gravity and, thus, also the turning moment which is to be counteracted by the counterbalancing mechanism.
- the invention facilitates retaining the drawing board vertically in a completely stable position by using a locking mechanism which is easily available and conveniently operable. This is achieved by the fact that the locking mechanism prevents the levers of the parallel motion guiding means from changing their mutual spacing. Such a change of the mutual spacing is connected with every change of the position of the drawing board vertically.
- the invention provides a locking mechanism for vertically adjustable drawing boards supported by a parallel motion guiding means, characterized in that two opposite levers of said means are provided each with a guide member for a pivoted link which is longitudinally displaceable in relation to at least one of said guide members said one guide member being formed as or provided with means for optionally preventing displacement of said link.
- the locking mechanism When the locking mechanism is engaged the link is prevented from displacement in relation to the guide member which means that there is no possibility of moving the levers of the parallel motion guiding means.
- the locking mechanism is disengaged such levers are free to move and the drawing board may be raised or lowered in the conventional manner.
- FIG. 1 is an elevational side view of a drawing table having a parallel motion guiding means for the drawing board and provided with a locking mechanism according to the invention
- FIG. 2 is an elevational side view of the drawing table according to FIG. 1 showing the drawing board in a horizontal position;
- FIG. 3 is a diagrammatical side view of a drawing table including another embodiment of the parallel motion guiding means and the locking mechanism provided therein the drawing board being shown in a position corresponding to that shown in FIG. 2;
- FIG. 4 is a diagrammatical side view in accordance with FIG. 3 of the arrangement shown therein but with the drawing board in a raised horizontal position;
- FIG. 5 is a sectional view of a simple embodiment of the locking mechanism according to the invention.
- FIG. 1 there is shown a drawing board 1 which is connected with a plate bracket 2.
- Bracket 2 is provided with bearings for two levers 3 and 4 pivotally connected therewith and allows for adjustment of the drawing board to different inclined positions by means forming no part of the present invention.
- Lever 3 is angled and is pivoted at the lower end thereof to a pedestal 5 to which is pivoted also a third lever 6 for swinging movement vertically.
- lever 3 is pivotally connected a triangular plate 9 at one corner thereof the plate having bearings for the pivoted connection of levers 4 and 6 at the other comers thereof.
- Drawing board 1 is supported at bracket 2 by levers 3 and 4 forming together with plate 9 and lever 6 a parallel motion guiding means, known per se, and may be adjusted vertically without changing the inclination of the drawing board.
- a link 8 In a bearing 7 provided for the connection of lever 4 to plate bracket 2 there is pivoted to said lever a link 8 at one end thereof. Furthermore, link 8 is guided by a guide member 10 provided on lever 3 said link being rotatably and displaceably guided on lever 3 by said guide member.
- Guide member 10 is formed as a locking member allowing link 8 to be rotated and displaced in relation to lever 3 when the locking guide member is disengaged.
- link 8 is con structed as a double link comprising two link members 11 and 12 disposed one at each side of lever 3.
- Link members 11 and 12 are each provided with longitudinally extending slots 13. Transversely through these slots and an opening formed by lever 3 extends abolt having a flat head 14, a portion 15 of square or rectangular cross-sectional form, and a threaded end portion 16, a nut 17 being screwed onto said latter portion.
- the nut is provided with an operating stick 18 by which the nut may be tightened against link member 11 which is thereby applied against lever 3, bolt 15 being forced in the opposite direction to be applied with head 14 thereof against link member 12 which is thereby applied against lever 3. Due to this engagement link members l1 and 12 are frictionally locked to lever 3 and are prevented to move in relation to said lever.
- the frictional force is provided directly between lever 3 and link members 11 and 12 and also between link member 11 and nut 17 and between link 12 and head 14 of the bolt which is non-rotatably mounted in lever 3.
- the pitch of the threaded end portion 16 may be great which means that the rotation of nut 17 for engagement and disengagement, respectively, may be relatively small.
- the change of the angular position of operating stick l8 and thus the change of the position of the outer end thereof will be correspondingly small which is advantageous considering the operation of the locking means.
- FIGS. 3 and 4 there is shown diagrammatically an embodiment wherein link 8 is pivoted to lever 3 and is rotatably and displaceably connected with lever 4 by means of guide member allowing the link to be locked to lever 4.
- the drawing board In FIG. 3 the drawing board is shown in a lower position, guide member 10 being received by the outer end of the slot provided in link 8. In the position according to FIG. 4 the drawing board is elevated to an upper position link 8 being displaced in relation to guide member 10 which is received by the inner end of the slot.
- the slot formed in the link must not necessarily be a straight slot.
- the link 6 projects from lever 4. This will be obviated by giving the link and the slot therein an arcuate form.
- the link may be formed in other ways than that described above.
- it is possible to form the link for instance as a bar which is displaceable in a bore extending diametrically through a rotatable pin.
- the locking mechanism may comprise for instance a stop screw screwed into a threaded bore extending at a right angle to the bore receiving said bar.
- an abutment such as the end wall of the slot or an abutment lug provided on the link may engage guide member 10 and thus limit the downward movement of the parallel motion guiding means.
- the linkcomprises a bar displaceable through a rotatable pin such abutment lug may be replaced by a nut screwed on the bar.
- a locking mechanism for vertically adjustable drawing boards comprising a parallel motion guiding means including two opposite levers, means mounting said levers for vertical swinging movement, means mounting said drawing board on said parallel motion guiding means, a guide member on each of said levers, a pivoted link connected to one of said levers by the associated guide member for rotational movement in relation to the lever and connected to the other one of said levers by the associated guide member for rotatiqnal movement and dis lacement longitudinally of said link in relation to the ever, and manually operable means for optionally preventing displacement of said link in relation to said other lever.
Abstract
A parallel motion guiding mechanism supporting a drawing board and including two opposite levers is provided with a link between the levers pivotally connected with one of the levers and connected with the other lever for rotational movement and displacement longitudinally of the link. A locking mechanism is provided to optionally lock the link to said other lever in order to prevent a change of the mutual spacing of the levers and thereby to prevent movement of the parallel motion guiding mechanism.
Description
United States Patent Selander [54] LOCKING MECHANISM FOR VERTICALLY ADJUSTABLE DRAWING BOARDS.
[72] Inventor: Bror Olle Herbert Selander, Malmo,
Sweden [73] Assignee: AB Spacio System, Malmo, Sweden [22] Filed: April 27, 1971 [21] Appl. No.: 137,793
[30] Foreign Application Priority Data April 27, 1970 Sweden ..5829/70 52 U.S.Cl ..10s/14s,108/10 [51] Int. Cl. ..A47d 9/00 [58] FieldofSearch ..10s/1o,14s;24s/421 [56] References Cited UNITED STATES PATENTS May..... .........108/10X [451 Nov. 21, 1972 3,089,275 5/1963 Alabor 108/145 X FOREIGN PATENTS OR APPLICATIONS 193,365 12/1964 Sweden ..l08/l0 Primary Examiner-James C. Mitchell AttorneyJones and Lockwood ABSTRACT A parallel motion guiding mechanism supporting a drawing board and including two opposite levers is provided with a link between the levers pivotally connected with one of the levers and connected with the other lever for rotational movement and displacement longitudinally of the link. A locking mechanism is provided to optionally lock the link to said other lever in order to prevent a change of the mutual spacing of the levers and thereby to prevent movement of the parallel motion guiding mechanism.
3 Claims, 5 Drawing Figures LOCKING MECHANISM FOR VERTICALLY ADJUSTABLE DRAWING BOARDS Drawing tables having vertically adjustable drawing boards, in which the supporting means for the drawing A board comprises a parallel motion guiding means, are subject to the drawback that they lack an effective and easily operable locking mechanism for retaining the drawing board in the desired vertical position.
The main object of the present invention is to remove this drawback.
Drawing tables of the type described now commonly used are generally provided with a counterbalancing mechanism. Such a mechanism is adapted to retain the drawing board in the vertically adjusted position which necessitates a very accurately calculated construction in view of the fact that the inclination of the drawing board effects the position of the center of gravity and, thus, also the turning moment which is to be counteracted by the counterbalancing mechanism.
When certain works are performed it is desirable or even necessary that the surface of the drawing board is kept horizontal. Then, it is often necessary that the draftsman when working on the remote parts of the board rests against the board more or less heavily. In such a case the counterbalancing mechanism per se cannot prevent the drawing board from changing its position vertically. This may be obviated to a certain extent for instance by increasing the friction of the joints of the parallel motion guiding means. However, inherently connected with this measure is a substantial reduction or a complete loss of one of the advantages provided by the parallel motion guiding means, i.e., the easy and convenient adjustment of the drawing board vertically. I
Attempts have also been made to lock one of the levers of the parallel motion guiding means to the frame supporting such means. These arrangements have turned out to be cumbersome to operate and, furthermore, difficult to fabricate due to the great forces necessary to keep the guiding means in a stationary position.
While maintaining all the advantages of the parallel motion guiding means the invention facilitates retaining the drawing board vertically in a completely stable position by using a locking mechanism which is easily available and conveniently operable. This is achieved by the fact that the locking mechanism prevents the levers of the parallel motion guiding means from changing their mutual spacing. Such a change of the mutual spacing is connected with every change of the position of the drawing board vertically.
Accordingly the invention provides a locking mechanism for vertically adjustable drawing boards supported by a parallel motion guiding means, characterized in that two opposite levers of said means are provided each with a guide member for a pivoted link which is longitudinally displaceable in relation to at least one of said guide members said one guide member being formed as or provided with means for optionally preventing displacement of said link. When the locking mechanism is engaged the link is prevented from displacement in relation to the guide member which means that there is no possibility of moving the levers of the parallel motion guiding means. However, when the locking mechanism is disengaged such levers are free to move and the drawing board may be raised or lowered in the conventional manner.
The invention now will be described in greater detail with reference to the accompanying drawing in which FIG. 1 is an elevational side view of a drawing table having a parallel motion guiding means for the drawing board and provided with a locking mechanism according to the invention;
FIG. 2 is an elevational side view of the drawing table according to FIG. 1 showing the drawing board in a horizontal position;
FIG. 3 is a diagrammatical side view of a drawing table including another embodiment of the parallel motion guiding means and the locking mechanism provided therein the drawing board being shown in a position corresponding to that shown in FIG. 2;
FIG. 4 is a diagrammatical side view in accordance with FIG. 3 of the arrangement shown therein but with the drawing board in a raised horizontal position; and
FIG. 5 is a sectional view of a simple embodiment of the locking mechanism according to the invention.
In FIG. 1 there is shown a drawing board 1 which is connected with a plate bracket 2. Bracket 2 is provided with bearings for two levers 3 and 4 pivotally connected therewith and allows for adjustment of the drawing board to different inclined positions by means forming no part of the present invention. Lever 3 is angled and is pivoted at the lower end thereof to a pedestal 5 to which is pivoted also a third lever 6 for swinging movement vertically. With lever 3 is pivotally connected a triangular plate 9 at one corner thereof the plate having bearings for the pivoted connection of levers 4 and 6 at the other comers thereof. Drawing board 1 is supported at bracket 2 by levers 3 and 4 forming together with plate 9 and lever 6 a parallel motion guiding means, known per se, and may be adjusted vertically without changing the inclination of the drawing board.
In a bearing 7 provided for the connection of lever 4 to plate bracket 2 there is pivoted to said lever a link 8 at one end thereof. Furthermore, link 8 is guided by a guide member 10 provided on lever 3 said link being rotatably and displaceably guided on lever 3 by said guide member.
In the embodiment disclosed in FIG. 5 the frictional force is provided directly between lever 3 and link members 11 and 12 and also between link member 11 and nut 17 and between link 12 and head 14 of the bolt which is non-rotatably mounted in lever 3. Thus, there are four friction surfaces, which is advantageous, since the locking means is then able to maintain the parallel motion guiding means in a stationary position even if nut 17 is not heavily tightened. The pitch of the threaded end portion 16 may be great which means that the rotation of nut 17 for engagement and disengagement, respectively, may be relatively small. The change of the angular position of operating stick l8 and thus the change of the position of the outer end thereof will be correspondingly small which is advantageous considering the operation of the locking means.
It is not necessary to provide the locking mechanism on the angled lever 3 as shown in FIGS. 1 and 2. In FIGS. 3 and 4 there is shown diagrammatically an embodiment wherein link 8 is pivoted to lever 3 and is rotatably and displaceably connected with lever 4 by means of guide member allowing the link to be locked to lever 4. In FIG. 3 the drawing board is shown in a lower position, guide member 10 being received by the outer end of the slot provided in link 8. In the position according to FIG. 4 the drawing board is elevated to an upper position link 8 being displaced in relation to guide member 10 which is received by the inner end of the slot.
The slot formed in the link must not necessarily be a straight slot. In the arrangement according to FIGS. 3 and 4 the link 6 projects from lever 4. This will be obviated by giving the link and the slot therein an arcuate form.
The link may be formed in other ways than that described above. Thus, it is possible to form the link for instance as a bar which is displaceable in a bore extending diametrically through a rotatable pin. In that case the locking mechanism may comprise for instance a stop screw screwed into a threaded bore extending at a right angle to the bore receiving said bar.
It is possible to modify the invention in other respects over those mentioned above. For instance, if it is sufficient that the drawing board is to be locked in a lower position only, then an abutment such as the end wall of the slot or an abutment lug provided on the link may engage guide member 10 and thus limit the downward movement of the parallel motion guiding means. Particularly if the linkcomprises a bar displaceable through a rotatable pin such abutment lug may be replaced by a nut screwed on the bar. In that case there is provided for an adjustment of the lower position of the drawing board which may be utilized tocompensate for a non-accuracy, if any, in the manufacture and to lower the production cost by allowing a wider tolerance zone. 7
What I claim is:
l. A locking mechanism for vertically adjustable drawing boards, comprising a parallel motion guiding means including two opposite levers, means mounting said levers for vertical swinging movement, means mounting said drawing board on said parallel motion guiding means, a guide member on each of said levers, a pivoted link connected to one of said levers by the associated guide member for rotational movement in relation to the lever and connected to the other one of said levers by the associated guide member for rotatiqnal movement and dis lacement longitudinally of said link in relation to the ever, and manually operable means for optionally preventing displacement of said link in relation to said other lever.
2. A locking mechanism as claimed in claim 1 v
Claims (3)
1. A locking mechanism for vertically adjustable drawing boards, comprising a parallel motion guiding means including two opposite levers, means mounting said levers for vertical swinging movement, means mounting said drawing board on said parallel motion guiding means, a guide member on each of said levers, a pivoted link connected to one of said levers by the associated guide member for rotational movement in relation to the lever and connected to the other one of said levers by the associated guide member for rotational movement and displacement longitudinally of said link in relation to the lever, and manually operable means for optionally preventing displacement of said link in relation to said other lever.
1. A locking mechanism for vertically adjustable drawing boards, comprising a parallel motion guiding means including two opposite levers, means mounting said levers for vertical swinging movement, means mounting said drawing board on said parallel motion guiding means, a guide member on each of said levers, a pivoted link connected to one of said levers by the associated guide member for rotational movement in relation to the lever and connected to the other one of said levers by the associated guide member for rotational movement and displacement longitudinally of said link in relation to the lever, and manually operable means for optionally preventing displacement of said link in relation to said other lever.
2. A locking mechanism as claimed in claim 1 wherein one of the guide members for the link is provided at the end of one of said levers the other one being provided between the ends of the other lever.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE5829/70A SE342772B (en) | 1970-04-27 | 1970-04-27 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US3703147A true US3703147A (en) | 1972-11-21 |
Family
ID=20267325
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US137793A Expired - Lifetime US3703147A (en) | 1970-04-27 | 1971-04-27 | Locking mechanism for vertically adjustable drawing boards |
Country Status (9)
| Country | Link |
|---|---|
| US (1) | US3703147A (en) |
| JP (1) | JPS5520685B1 (en) |
| CA (1) | CA942821A (en) |
| CH (1) | CH522380A (en) |
| DE (1) | DE2120652A1 (en) |
| FR (1) | FR2090781A5 (en) |
| GB (1) | GB1352352A (en) |
| SE (1) | SE342772B (en) |
| ZA (1) | ZA712716B (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4383486A (en) * | 1980-07-28 | 1983-05-17 | Rol-Fol Table, Inc. | Desk for handicapped persons |
| US5522323A (en) * | 1993-08-24 | 1996-06-04 | Richard; Paul E. | Ergonimic computer workstation and method of using |
| US5704299A (en) * | 1996-04-05 | 1998-01-06 | Haworth, Inc. | Keyboard support |
| US5823120A (en) * | 1990-11-13 | 1998-10-20 | Jeltec Ergonomiteknik Ab | Vertically adjustable desktop, preferably a school desk |
| US6691626B2 (en) * | 2002-02-19 | 2004-02-17 | Steve Warner | Adjustable table |
| US20170081798A1 (en) * | 2015-01-23 | 2017-03-23 | Koninklijke Philips N.V. | Garment steamer with inclinable ironing board |
| US9743760B1 (en) * | 2016-02-22 | 2017-08-29 | Teknion Limited | Furniture piece with adjustable worksurface |
| US10932561B2 (en) * | 2019-08-02 | 2021-03-02 | Zhuhai Runxingtai Electrical Co., Ltd. | Stepless adjustable telescopic device and method using the same |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6276265U (en) * | 1985-10-31 | 1987-05-15 |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3079726A (en) * | 1961-02-17 | 1963-03-05 | Mayline Co | Lock mechanism for drafting table |
| US3089275A (en) * | 1960-06-08 | 1963-05-14 | Alabor Paul | Drawing stands or the like |
-
1970
- 1970-04-27 SE SE5829/70A patent/SE342772B/xx unknown
-
1971
- 1971-04-26 CA CA111,366A patent/CA942821A/en not_active Expired
- 1971-04-27 FR FR7114953A patent/FR2090781A5/fr not_active Expired
- 1971-04-27 DE DE19712120652 patent/DE2120652A1/en active Pending
- 1971-04-27 GB GB1160471*[A patent/GB1352352A/en not_active Expired
- 1971-04-27 ZA ZA712716A patent/ZA712716B/en unknown
- 1971-04-27 US US137793A patent/US3703147A/en not_active Expired - Lifetime
- 1971-04-27 JP JP2787471A patent/JPS5520685B1/ja active Pending
- 1971-04-27 CH CH614571A patent/CH522380A/en not_active IP Right Cessation
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3089275A (en) * | 1960-06-08 | 1963-05-14 | Alabor Paul | Drawing stands or the like |
| US3079726A (en) * | 1961-02-17 | 1963-03-05 | Mayline Co | Lock mechanism for drafting table |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4383486A (en) * | 1980-07-28 | 1983-05-17 | Rol-Fol Table, Inc. | Desk for handicapped persons |
| US5823120A (en) * | 1990-11-13 | 1998-10-20 | Jeltec Ergonomiteknik Ab | Vertically adjustable desktop, preferably a school desk |
| US5522323A (en) * | 1993-08-24 | 1996-06-04 | Richard; Paul E. | Ergonimic computer workstation and method of using |
| US5704299A (en) * | 1996-04-05 | 1998-01-06 | Haworth, Inc. | Keyboard support |
| US6691626B2 (en) * | 2002-02-19 | 2004-02-17 | Steve Warner | Adjustable table |
| US20170081798A1 (en) * | 2015-01-23 | 2017-03-23 | Koninklijke Philips N.V. | Garment steamer with inclinable ironing board |
| US9816224B2 (en) * | 2015-01-23 | 2017-11-14 | Koninklijke Philips N.V. | Garment steamer with inclinable ironing board |
| US9743760B1 (en) * | 2016-02-22 | 2017-08-29 | Teknion Limited | Furniture piece with adjustable worksurface |
| US10932561B2 (en) * | 2019-08-02 | 2021-03-02 | Zhuhai Runxingtai Electrical Co., Ltd. | Stepless adjustable telescopic device and method using the same |
Also Published As
| Publication number | Publication date |
|---|---|
| ZA712716B (en) | 1972-01-26 |
| CH522380A (en) | 1972-06-30 |
| JPS5520685B1 (en) | 1980-06-04 |
| SE342772B (en) | 1972-02-21 |
| GB1352352A (en) | 1974-05-08 |
| CA942821A (en) | 1974-02-26 |
| FR2090781A5 (en) | 1972-01-14 |
| DE2120652A1 (en) | 1971-11-11 |
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