AU600682B2 - Improved clamp - Google Patents

Description

COMtMONWLEALTH OF AU.ST PILIA Form Regulation 13 2) W r PATENTS ACT, 1952 COMPLETE SPECIFICATION

(ORIGINAL)

FOR OFFICE USE 06 8 2 Short Title: Int. Cl: Application Nuber: Lodged: Complete Specificati Ct 4- 13iL C on-Lodged; Accepted; Lapsed: Published: Priority: 0 0 000 0 000 oa ±-'LB.j Related Art: TO BE COMPLETED BY APPLICANT Name of Applicant: BERNARD CARL PASFIELD Address of Applicant: 12 Crown Street, Toukley N.S.W. 2263 1 a t1 r a Actual Inventor: Address for Service: Bernard Carl Pasfield ARTHUR S. CAVF CO., Patent and Trade Mark Attorneys, 1 Alfred Street, Sydney, New South Wales, Australia, 2000.

Complete Specification for the invention entitled: "IMPROVED CLAMP" The follo!ing statement is a full description of this invention, including the best method of performing it known to me:- -1- ASC-49 4100T/AT 3/% IMPROVED CLAMP The present invention relates to an improved clamp adapted for use in conjunction with a supporting base for holding articles of a variety of sizes.

In particular, the invention relates to a clamp mounted on a trestle, the configuration of the trestle enabling the clamp to hold articles in cantilevered fashion and providing restraint against overturning which can be caused by either the self weight of the clamped article or by the performance of an operation, such as cutting, on the article.

A number of trestles for use in supporting and/or holding objects when they are to be cut are known in the building industry and in the domestic sphere. Among these is the basic trestle which is comprised of frame supporting legs fixed at either end of a support beam on which the material to be supported is laid. This trestle must normally be used in conjunction with at least one other trestle so the material to be cut can bridge the two trestles. These basic trestles do not have the facility for clamping the materials to be worked on. Their principal role is to provide simple support for articles.

Generally, there is no facility for clamping The articles to be worked upon, and the worker must manually nold the 0 aL G I articles while the particular operation (such as cutting, 00 routing, planing or drilling) is being carried out.

This creates dangers to the operator when power tools are used as the holding hand is often placed near to the moving part of the equipment to achieve optimum support for the -2- L I~ article being worked on. If the article is not held by hand, when the tool is applied to the work, the material can tilt or move away from the operator. Some measures have been taken to ameliorate these problems by placing nails in the support beam to restrain the material, however, this has proved to be a tedious practice and can be a nuisance when a great variety of materials of different shapes and sizes are to be worked on on the trestle.

An improvement was made to the basic trestle by incorporating in a supporting platform a manual means to divide the platform into two halves. With the platform in two halves, a recess is created into which the material to be worked on can be placed. The material can then be clamped by closing the two halves of the platform against the material thereby securing it for cutting.

Despite this improvement this trestle has shortcomings.

Firstly, it is intended for use with articles with relatively small cross sectional dimensions.

o0 It is not suitable for use when the article to be held 2Q forms a long cantilever as the trestle is likely to overturn at least in the direction of the cantilevered portion of the article. These trestles are also generally used in conjunction with another trestle, with the article to be worked on spanning there between and being simply supported by both trestles.

When a piece of timber which spans between two simple supports is cut in a position between the supports, the cut portion tends to rotate downward thereby gripping the saw blade. This is undesirable both from safety and operational 3 points of view. Also, the resultant quality of the ends of the I cut timber can be reduced by causing a ripped finish.

j The present invention seeks to overcome these and other related problems by providing an improved clamp for mounting on prblm prvdn mpoeo a fixed or free standing support which can securely hold an article which can be cantilevered to a considerable distance from the clamp without compromise to overall stability. The improved clamp is intended for use on its own and eliminates u3 the need for additional support for the article being clamped.

Thus the present invention eliminates the need for co-operating trestles. It has the facility for rigidly clamping an article and can be adjusted according to the size of the article or articles to be held.

In its broadest form the present invention comprises: a clamp adapted for mounting a fixed or free standing support means, said clamp comprising: a base means for supporting an article to be held in the o00 0 0 A Sclamp; an adjustable member mounted on at least one guide post; 0000 wherein, when an article is to be clamped the said 00 00 S article is placed on the said base means; the said adjustable member being brought into engagement with said article, thereby clamping the article between the f adjustable member and the said base means, wherein the support means comprises a stand having three spaced apart legs forming a substantially tripod configuration, two of said legs being disposed in a direction forward of said clamp, the third of said legs being disposed in a direction rearward df the said SO_ AJG 4 u 1clamp, the disposition of the legs enabling the holding of an elongate article extending forward of said clamp between the said two legs beyond the area of the legs while providing resistance against overturning in the forward/rearward direction.

a base means for supporting an article to be held in the clamp; an adjustable member mounted on at least one guide post; wherein, when an article is to be clamped the said article is placed on the said base means; o the said adjustable member being brought into engagement Vwith said article, thereby clamping the article between the adjustable member and the said base means, wherein the support means comprises a stand having three spaced apart legs forming a substantially tripod configuration, two of said legs being disposed in a direction forward of said clamp, the third of said legs being disposed in a direction rearward of the said clamp, the disposition of the legs enabling the holding of an elongate article extending forward of said clamp beyond the area of the legs while providing resistance against overturning in any directionprovide resistance against overturning in any direction.

Preferably the clamp comprises a base member and a beam member which is mounted on two spaced apart vertical guide posts which are mounted on the base member and whose vertical position is adjustable along the length of the said vertical posts according to the size of the article to be clamped.

The base means is adapted to receive a great variety of 88k/AJG 5 A major advantage of the present invention is that cutting timber with a chain saw for instance is made far easier. This is due to a number of factors. Firstly, long lengths of timber can be supported by clamping on a single trestle support.

Continual feeding of the article is no longer necessary; that is, the saw can be brought to the article rather than the article being fed towards the saw.

The presently known devices do not provide for clamping of a large variety of articles from the small to the large, nor do they offer stability when articles are cantilevered.

The invention will now be described in detail according to non limiting embodiments with reference to the accompanying illustrations wherein: Fig. 1 shows an isometric view of the adjustable clamp mounted on a trestle according to one embodiment of the present invention; Fig. 2 shows a side view of the clamp in Fig. 1 with an article mounted therein; Fig. 3 shows the clamp in its folded configuration; a Fig. 4 shows an exploded view of the clamp for mounting on a trestle according to an alternative embodiment; and

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Fig. 5 shows an end view of the bar assembly with the handle mechanism affixed thereto.

Fig. 1 shows the adjustable clamp 1 mounted on a trestle from a rear view. In the preferred embodiment, the clamp 1 is mounted atop of a supporting stand 3 which is in the nature of a trestle. The trestle enables the clamp to be particularly useful for supporting elongated articles such as lengths of timber or pipe such that they are cantilevered from the clamp.

This necessitates the reliably stable supporting stand 3. The clamp essentially comprises a base means 2 for supporting articles and a moveable beam 19 mounted on preferably two guide posts. The fact that the clamped articles are cantilevered, as distinct from being simply supported, creates an overturning tendancy in the support means or trestle both under the weight of the article held (which moment is magnified by the length of the moment arm) and also as a reaction to an operator exacerbating the overturning moment by creating loads when working on the particular article being held.

The supporting stand 3 preferably has three legs 4, 5 and 6 positioned so as to counter the lateral and longitudinal overturning tendancy which can be created by elongated clamped articles.

Two of the legs 4 and 5 are positioned so their feet bear on the ground at a distance well forward of the clamp so that the overturning pivot point is located well forward of the clamp imparting stability to the trestle when an elongated article is held. This is so even when the article being held by the clamp extends outside the area defined by the positions of the feet.

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Legs 4 and 5 can be adapted in a manner (not shown) to telescopically extend or retract depending upon the anticipated overturning moment to be resisted which is created by the particular article being clamped.

The legs 4 and 5 can also be adapted such that they swing laterally relative to the longitudinal axis of the article to 7 be held. This can be done by means of pivot hinges 7 and 8 as shown in Fig. i. This facility for lateral variation in leg positions helps resist lateral overturning which could be created by, for instance, sideways cutting of an article being supported by the trestle.

A leg 6 is located rearward of the clamp and acts as a stabilising strut. Although not shown, this leg can also be adjusted telescopically to vary the height of the clamp. Also the leg can be hinged so it can be moved in a variety of positions in the longitudinal or lateral directions.

Ideally, the feet of the three legs 4, 5 and 6 when in the most suitable configuration define an area forming an isoceles triangle.

It is envisaged that the trestle support pedestal could alternatively be formed by a continuous base bearing on the ground surface defining the sides of and enclosing an area forming either a circle, square, triangle, rectangle or other suitable shape, depending upon the stability needed for a particular use.

The clamping apparatus as shown in Fig. 1 is preferably comprised of at least two spaced apart saddle members 9 and which are attached to each other b: bars 11, 12, 37 and The saddle member 9 is attached to the supporting stand 3 by means of struts 13 and 14 which are fixedly attached to legs 4 and 5 respectively at one end of the struts and to spaced apart hinge pins 7 and 8 at the other end of the struts. The hinge pins 7 and 8 are pivotally mounted to span between the saddles 9 and 10. Each end of the hinge pins are supported by penetration into holes prepared in the saddle members.

Each saddle member is profiled in such a way that many of the standard size cross section cuts of timber can fit into the accommodating recesses 16 located therewithin. Circular articles can also be held in the recess 16 along with articles chosen from a variety of cross-sectional shapes.

Saddle member 9 merely acts as a bearing to simply support the article being worked on. It is not necessary that clamping of the article takes place on saddle 9, however, if extra clamping is required a clamping mechanism could also be adapted to saddle 9.

Fixedly attached to the extremities of saddle 10 are vertical posts 17 and 18 which are adapted to support a vertically adjustable beam 19.

Beam 19 is comprised of a first member 20 fitted with guiding lugs 21 and 22. This member 20 attaches to a second member 23 by means of a through bolt 24. The members 20 and 23 are also attached by means of ancillary fixing bolts When members 20 and 23 are coupled together a recess 26 is formed by virtue of fabricated kinks 27 and 28.

The recess 26 which can be seen in Fig. 1 is adapted to receive vertical posts 17 and 18.

When the beam 19 is mounted on these vertical posts it's position can be adjusted according to the size of the article to be held.

When an adjustment is required to the size of opening 29 height adjustment locking buttons 30 and 31 are first unscrewed.

Next, the levers 32 and 33 are simultaneously rotated to 9 release arms 39 which e ,e notches 3 and 40 preformed by serrations in the vertical members 17 and 18.

In use, before the article to be held is loaded onto the trestle, the bridging beam 19 is adjusted to approximate the size of the said article.

Height adjustment locking buttons 30 and 31 are tightened and the levers 32 and 33 engage the notches 34.

The article can then be loaded onto the saddles 9 and then pushed through the opening 29.

With the article in position the beam 19 can then be released thereby falling down onto the article and thereby creating a tight clamping.

In an alternative embodiment (not shown) the clamping beam and posts are located centrally on the base means. The clamp 1 disposed in this position on the trestle allows effective two way cantilever clamping ot a member to be held.

In another embodiment the levers 32 and 33 can be activated simultaneously by using one hand activating a clamp operationally interconnected with levers 32 and 33 located substantially centrally between the guide posts.

Beam 19 can be adapted with a bolt passing through the beam to act as a fine tightener to ameliorate any deleterious effects created by any play between the beam 19 and the article being held.

Fig. 2 shows the clamp according to one embodiment holding a length of timber 35 cantilevered to a considerable distance from the clamping end.

The tendancy of the timber in this instance is to rotate 10

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downwards and thereby overturn the trestle.

The centre of gravity of the trestle with the timber beam clamped thereon is located rearward of feet 36 and 38 of the legs 4 and 5 thus imparting stability to the apparatus by creating a restoring moment to counteract the overturning moment created by the timber article.

In an alternative embodiment, the legs 4 and 5 can be made telescopically adjustable to locate the feet which are the pivot point of overturning in a position whereby the restoring moment created by virtue of their position can always exceed the overturning moment for the particular article to be held.

In another embodiment, the legs 4 and 5 can be moved laterally to counteract lateral overturning tendencies when performing work on the clamped article.

Fig. 3 shows the clamp folded with legs 4 and 5 rotated together and leg 6 rotated between the said legs.

Although, not shown, in one embodiment the legs 4 and can be folded further either telescopically or pivotally.

Fig. 4 shows an alternative embodiment of the clamp of the present invention wherein the mechanism of operation of the bar arrangement has been changed.

The remainder of the clamp and the stand is essentially the same as depicted in the embodiment of Fig. i.

Fig. 4 depicts an exploded detailed view of one end of the bar arrangement according to the alternative embodiment.

This arrangement comprises a first bar 40 which is adapted for attachment to an opposing second bar 41 by screws or bolts 42. First bar 40 has a block 43 attached to each end. Block 11

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43 is adapted with a passage 44 to receive plunging rod which is attached to locking pawl 46. Locking pawl 46 when actuated slides between guide blocks 47 and 48.

When bar 40 and 41 are coupled together the rod 49 which is connected to locking pawl 46 protrudes through the elongated slot 50. The handle mechanism 51 is shown in abutment with guide post 52 for clarity, however, when the bar asr.embly is assembled, the handle mechanism is disposed outside bar 41.

When the bar mechanism is in the locked position the tapered end 53 of the locking pawl 46 engages one tooth on the teeth array 54 on the guide post 52. The end 53 of pawl 46 is urged into the bottomlands of the selected tooth by means of actuating spring 55 which is concentrically disposed along plunging rod When the position of the bridging bar arrangement is to be changed, the bar 56 is gripped with the palm of the hand allowing the fingers to grip bar 57. When bar 57 is squeezed its attachment to telescopic sleeve 58 causes the sleeve to slide upwards on member 59. Connected to the sleeve 58 is a shaft 60 having a tapered end 61. When sleeve 58 rides on member 59 a caming action created between the tapered end 61 and the rod 49 causes the locking pawl 46 to move away from the teeth 54 in the direction of arrow 62 causing spring 55 to be compressed. This enables the bar assembly to be moved to any position along the guide post 52. When grip bar 57 is released, the restoring force in the spring 55 forces the locking pawl into an aligned tooth selected from the teeth array.

12 The same action occurs at the opposite end of the bar mechanism enabling locking of the bar so each end is in alignment.

SIn the preferred embodiment the member 59 has a return portion 63 which passes through holes 64 and 65. Fig. 5 shows an end view of the bar mechanism connected with the handle mechanism 51 attached.

When the clamp is to be loaded with an article bar 57 is squeezed to cause release of the locking pawl 46 from the teeth array 54. The handle 56 is pulled upwards until holes 66 and 67 are in alignment. When this occurs plunger 68 is pressed into holes 66 and 67. The plunger is frictionally held in the said holes by the weight of the beam mechanism.

When an article is inserted, the article pushes up the 13 beam mechanism releasing plunger 68 under the action of spring 69. The beam then gravitates under its own weight onto the article thereby clamping the article as the locking pawl 46 engages a tooth in the array 54.

It will be recognised by persons skilled in the art that numerous variations and modifications may be made to the invention as described above such as, but not limited to, making the device from different materials, varying the stand configuration, increasing the number of clamps on the platform, increasing the distance between and height of the guide posts to accommodate larger articles, without departing from the overall spirit and scope of the invention.

13 1. I NaMMUNUMM

Claims (13)

1. A clamp adapted for mounting a fixed or free standing support means, said clamp comprising: a base means for supporting an article to be held in the clamp; an adjustable member mounted on at least one guide post; wherein, when an article is to be clamped the said article is placed on the said base means; the said adjustable member being brought into engagement with said article, thereby clamping the article between the adjustable member and the said base means, wherein the support means comprises a stand having three spaced apart legs forming a substantially tripod configuration, two of said legs being disposed in a direction forward of said clamp, the third of said legs being disposed in a direction rearward of the said clamp, the disposition of the legs enabling the holding of an elongate article extending forward of said clamp between the said two legs beyond the area of the legs while providing resistance against overturning in the forward/rearward direction.

2. A clamp according to claim i, characterised in that the guide post or posts are connected to the base member.

3. A clamp according to claim i, characterised in that the .1 adjusted member is a resilient beam which is moveably attached at or near one of its ends to the said guide post or posts.

4. A clamp according to claim 3, wherein the said beam is connected to and spans between two spaced apart guide posts.

A clamp according to claim 4, wherein the said guide ;,0288k/AJG 14 /4 -2- I 1IIi, l l i i posts are adapted with means for enabling the location of the said beam in selected positions along the length of the guide posts.

6. A clamp according to claim 5, wherein the said location means comprises a sawtooth array on the outside edge of the guide posts.

7. A clamp according to claim 6, wherein the said beam has a locking means at either end which engages the said sawtooth array on each post, with the assistance of biasing means.

8. A clamp according to claim 7, wherein the said locking means comprises a tapered pawl, also having a stem protruding from a surface of the pawl.

9. A clamp according to claim 8, wherein the. said arm is adapted with a gripping handle having a slideable grab bar attached thereto, said grab bar having a cam surface connected oo oo thereto which engages said stem on said locking pawl enabling retraction of said locking pawl when said grab bar is pulled I thereby enabling said arm to be moved along said guide posts.

A clamp according to claim 9, wherein the said guide posts are each adapted with holes which align with a hole or holes in the beam to enable the insertion in said hcles of a tripping mechanism attached to said beam and comprised of a spring loaded rod adapted for manually pushing into said holes, said rod being held within said holes under the weight of said beam.

11. A clamp according to any one of claims 1 to 10, wherein the disposition of the legs enables the holding of an elongated article whose body extends beyond the area defined by the legs. .wO1 k/AJG -15 \idpili 1 *I At'

12. A clamp according to claim 11, wherein the said legs are hingedly and telescopically adjustable.

13. A clamp as hereinbefore described with reference to the accompanying drawings. DATED this 21st day of February, 1990. BERNARD CARL PASFIELD By His Patent Attorneys ARTHUR S. CAVE CO. 0288k/AJG 16 C) I~ 0 .3