Machine elements in the form of profiles telescopically movable relative to each other
This invention relates to a machine element in the form of preferably rectangular profiles telescopically movable relative to each other.
Within a plurality of technical fields there is a need of a machine element which can be extended or shortened, if desired, i.e. be adjusted to an intended length, whereby it is required at the same time that the machine element should have at least one continuous even edge independently of the adjusted length of the element.
The need can e.g. be such a longitudinally adjustable machine element to be used as a rule, measuring tool, water- level, control board (i.e. tool for levelling gravel and concrete surfaces), vibrating screed (e.g. for concrete levelling), building element such as beam, shoring, tele¬ scopic pole, table leg, rail etc.
So far known longitudinally adjustable tools or machine elements in the form of profiles telescopically movable rela- tive to each other are all beset with the drawback that the transition between the profiles is not continuous, indepen¬ dently whether the element is placed on its edge or not, but shows a discontinuity in the form of a step usually corre¬ sponding to the material thickness of the profiles. By the present invention being given the characteristic features indicated in the claims it is possible to provide a machine element, e.g. a rule or control board or some other type of element mentioned above having a measuring and a levelling edge, respectively, which is continuously even but is lacking the steps occurring at previous, elements, which steps must be compensated in some way or other when using the element.
The invention will be described in greater detail with reference to the drawing, in which Fig. 1 is a perspective of the machine element according to the invention, Fig. 2 shows a section of an element in a somewhat changed embodi¬ ment, Fig. 3 shows another embodiment of the element of the invention and Fig. 4 shows an end of the element shown in Fig. 3 as seen laterally.
As is apparent from Fig. 1 the device of the invention consists of a first outer profile 1 , which supports tele¬ scopically movably a second interior profile 2. As appears from Fig. 1. as well as Fig. 2 the outer profile has rectangu- lar form and has a quite open side. The free edges of the outer profile forming the open side are each made as a cutting edge 3, the tip of which lies in the plane of the profile side. The other interior profile 2 has a closed, substantially rectangular form and fits displaceably in the first profile. The profile 2 has a side 4 which covers the open side of the outer profile 1. The side is in turn limited by two edges 5 similar to cutting edges. As the side 4 has a width greater than that of the interior profile 2 and corresponding to the width of the open side of the outer profile 1 the edges 5 of the side 4 will with their tips, be on a level with the outer opposite lateral plane of the profile.
As is clearly evident from Figs. 1 and 2 a distinct edge or a corner of the machine element according to the invention is accomplished which edge forms a continuous straight line independently of the reciprocally displaced position of the profiles 1 and 2 and independently of whether the element is more or less inclined to the support. The edges 3 and 5 formed in the first profile 1 and the other profile 2 are preferably achieved in that the profiles 1 and 2 have e.g. portions 6 and 7, respectively, inwardly inclined 45 . To control and retain the interior profile 2 in the outer profile 1 the inclined portions 6 thereof preferably terminate in a hook-shaped portion 8, which co-operates with a groove formed by a hook- shaped portion 9 in the interior profile 2. It is apparent from Fig. 1 that the hook-shaped portion. 9 is formed by wall portions parallel to the wider sides and the corresponding hook-shaped portion 8 of the outer profile 1 is parallel to the wider sides thereof. A screw whose head is running in a groove 10 made in the interior profile 2 extends through a hole* in the outer profile 1. A wing nut 11 is threaded onto the screw, the profiles 1 and 2 being locked relative to each other when the nut is tightened on the screw. It appears from Fig. 2, as distinguished from what is shown in
Fig. 1 , that the hook-shaped portions 8 and 9 are inclined relative to the wider sides of the profiles. At the same time the screw, here designated 12, is provided with a head which has suitably a square cross sectional form and has an oblique surface turned from the side 4, as is apparent from Fig. 2, co-operating with a corresponding oblique side of the groove 10 in the interior profile 2. Through the square form of the screw head this is non-rotatably guided in the groove 10 and when the wing nut 11 is tightened the screw head will be drawn inwardly and press the interior profile 2 upwards (see Fig. 2), i.e. inwards in the first profile 1. In this way the co-operating oblique surfaces 8' and 9' of the hook-shaped portions 8 and 9, respectively, will simul¬ taneously tend to move the sides of the outer profile 1 towards each other, and the outer profile can be said to "be clamped" against the edge 4 of the interior profile.
In Figs. 3 and 4 there is shown another embodiment of the invention. In this case the first outer profile, here designated 13, has two opposite open sides defined by in- clined portions 7, which form with the wide sides of the profile 1 the aforesaid cutting edges 3. Two other interior profiles 14 run in the outer profile 13, which are rigidly connected at one end with one another by means of a yoke 15. When the interior profiles 14 are quite pushed into the outer profile 13 this yoke 15 will form a closing end portion of the outer profile. The two interior profiles 14 show in prin¬ ciple similar guiding hook-shaped portions 9 which as previously described, co-operate with hook-shaped portions 8 in the outer profile 13. Locking of the two interior profiles 14 in the outer profile 13 in a desired position is carried out by means of a screw with head and a wing nut, e.g. in a previously described way. In Fig. 3 an embodiment is shown in which the screw is arranged within the double web 18 of the outer profile straight between the two interior profiles 14 and supports an expansion means 16. When tightening the wing nut 11 the expansion means will act against the "bottom sides" of the interior profiles 14 via openings in the web of the first profile 13 and fix these in the outer profile 13.
17 designates a scale of lengths arranged at the respective profile, by means of which it is possible to read directly the current length of the element.
It is to be understood that the very fixing of the second or interior profile 2 and 14, respectively, longi¬ tudinally, in the first or outer profile 1 and 13, respec¬ tively, can be made in a plurality of various manners and this is no part of the very invention. Many different solutions suitable for the purpose appear for one skilled in. the art. Within the scope of the -invention the guiding of the second profile in the first profile can of course also be accomplished in many ways. Only some suitable and practical embodiments have been described here.