DEVICE FOR LOCKING A MEMBER DISPLACEABLE ALONG A BAR
The present invention relates to a device for use in a stapler for locking a member displaceable along a bar in an optional displacement position, said member carrying a catch for the object to be stapled, and said device having a locking means formed with a through hole through which the bar extends and which is designed such that the locking means is nonrotatably connected to the bar but is tiltable therealong between a free position wherein the locking means is freely displaceable along the bar, and a pinch position wherein the locking means is pinched to the bar.
Locking in an optional position of e.g. a catch disposed on an electric stapler and displaceable along an operating bar is achieved by means of locking mecha¬ nisms of different kinds. Some of these locking mecha¬ nisms are not continuously adjustable, i.e. the catch can be locked to the bar only in certain predetermined positions. Because the catch, serves int. al. as a stop for the object to be stapled, only certain stapling depths, i.e. distances from the edge of said object to the staple that is to be stapled into the object, are obtainable with a locking mechanism which is not continuously adjustable. In most electric staplers, the catch operating bar is disposed along one of the longitudinal sides of the stapler. The prior art locking mechanisms are of such construction that they must be operated from the side, implying that one must have free access to this longitudinal side for operating the locking mechanism to release the catch, and for displacing the catch along the operating bar to the desired position and for subsequently operating the locking
mechanism such that the catch is again locked to the bar.
However, in such applications where more than one staple is needed in the object to be stapled, it may be desirable, for higher efficiency of operation, that all the staples should be driven into the object at the same time. This is achieved the most simply by arranging a plurality of staplers side by side in a long row, which however makes it difficult to gain access to the longitudinal side of each stapler when the position of the catch has to be altered.
The object of the present invention, therefore, is to provide a simple and cheap device for locking a catch disposed on an electric stapler and displaceable along a bar, in an optional position of displacement on the bar. The locking device makes it possible both to release, displace and lock the catch by operating the catch from in front, and to lock the catch to the bar in any desired position of displacement along the bar.
This object is achieved by means of a locking device of the above-mentioned type which, according to the invention, is characterised in that the locking means is disposed in a slot in the displaceable member, two opposed wall surfaces of the slot forming on the one hand a carrier means adapted to carry along the locking means when the displaceable member is displaced along the bar and, on the other hand, an engagement means adapted to engage the locking means in order to tilt the latter between its free position and its pinch position when the bar and hence the locking means are turned, the locking means in its pinch position locking the displaceable member to the bar in cooperation with the carrier means. In a preferred embodiment, a torsion spring is arranged to turn the bar and hence the locking means, such that the latter is tilted to its pinch position
by the engagement means.
The locking means is preferably a washer. Preferably, the central axis of the through hole in the washer forms an angle H with the plane of the washer, $ ≠ 90°.
The opposed wall surfaces are preferably plane surfaces forming an angle α with the axis of the bar, α ≠ 90°.
Conveniently, α and β are of the same size, pre- ferably 95°-100°.
The invention will be described in more detail below, reference being had to the accompanying drawings. Fig. 1 is a side view of a locking device according to the present invention, used in an electric stapler, a member displaceable along a bar being shown in a position where it is freely displaceable along the bar.
Fig. 2 is a part sectional view of the device according to Fig. 1.
Fig. 3 shows the device of Fig. 1 in a position where the displaceable member is locked to the bar. Fig. 4 is a part sectional view of the device shown in Fig. 3.
The displaceable member shown in Fig. 1 is a runner 1 having a body with an upper part 2a and a lower part 2b. Both the upper and the lower body part are of substantially rectangular shape, the upper part 2a having a horizontal through hole 3 through which extends a hexagonal bar 4.
The upper part 2a also has a through slot 5 extending straight through the hole 3, such that its two upwardly extending opposed wall surfaces 5a, 5b which are flat surfaces, form an angle α with the central axis of the hole 3 and hence with the axis 4 of the bar. The angle a ^ 90° preferably lies in the range 95°-100° and is 97° in the embodiment shown.
Fig. 2 shows a washer 6 with a hexagonal through
hole 7, the central axis of which forms an angle β with the plane of the washer. The angle β ≠ 90° preferably lies in the range 95°-100° and is 97° in the embodiment shown. As is seen from Fig. 1, the washer is disposed in the slot 5 around the bar 4 and, in the position shown in Fig. 1, is urged to bear against one of the wall surfaces of the slot 5 by a cup spring 8. When the runner 1 is displaced on the bar 4, the washer 6 will thus be carried along by the wall surface 5a and the wall surface 5b via the cup spring 8.
It is also seen from Fig. 1 that the runner 1, at its upper end, has a groove 9 in which a slide bar 10 for guiding the runner 1 engages. In this Figure, it is also shown that the slot 5 widens in the direction towards the groove 9, a catch (not shown) being pivotally connected to the runner by means of a pin (not shown) extending through the widened portion of the slot 5. This catch serves on the one hand as a stop for the object to be stapled, i.e. the stapling depth is changed by displacement of the runner 1 and hence of the catch along the bar 4, and on the other hand as a releasing device for the stapling stroke of the electric stapler. Furthermore, the bar 4 is placed along one of the longitudinal sides of the electric stapler, its front end being provided with an operating knob 11 nonratably connected to the bar, and its tapering rear end being provided with a torsion spring 12 adapted to turn the bar 4 and hence the washer 6 towards the position shown in Fig. 3.
A compression spring 13 is also disposed around the bar 4 between the torsion spring 12 and the runner 1 and is adapted to displace the runner 1 and hence the catch towards the operating wheel 11, when the runner 1 is not locked to the bar.
The function of the locking device will now be
described in more detail. When the bar 4 is turned by means of the operating knob 11, the washer 6 is turned together with the bar because the bar 4 and the hole 7 of the washer 6 have the same cross-section which, as mentioned above, is hexagonal in this embodiment, and are of about the same dimensions. The washer is, in other words, nonrotatably connected to the bar 4.
As the central axis of the hole 7 of the washer 6 does not form a right angle with the plane of the washer, the angle γ between the plane of the washer and the axis of the bar will change upon turning of the washer. In the turning position where the angle γ is of the same size as the angle α between the wall surfaces 5a, 5b of the slot and the axis of the bar 4, the plane of the washer 6 will be parallel to the wall surfaces of the slot 5, and in this position (see Fig. 1) the washer 6 is urged to bear against the wall surface 5a by the cup spring 8. Because, in this position, there is a certain play between the hole 7 of the washer 6 and the bar 4, the washer and hence the runner 1 are now freely displaceable along the bar 4, and said position is therefore in the following called the free position of the washer. If the bar 4 and hence the washer 6 are then turned in either direction, the wall surface 5a will, due to its engagement with the washer 6, cause the washer to tilt about an axis perpendicular to the bar until the washer 6 takes the position shown in Fig. 3. At this point, the bar has been turned through about 90°.
As is evident from Fig. 4, the washer 6 is in this position pinched to the bar 4, and said position is therefore in the following called the pinch position of the washer. When the washer 6 is in its pinch position it locks, due to its engagement with the wall surfaces 5a, 5b, the runner 1 and hence the catch to the bar
(see Fig. 3) .
Because the torsion spring 12, as was pointed out above, in this embodiment is arranged to turn the bar 4 and hence the washer 6 towards the position shown in Fig. 3, i.e. the pinch position of the washer, the bar 4 will be urged, as soon as it is not subjected to any external influence, into such a position that the washer and hence the runner are locked to the bar. For example, if it is desired to reduce the stapling depth of the stapler, the object to be stapled is first inserted into the stapler to the desired depth of stapling and then the bar 4 is turned by the operating knob 11 until the washer 6 is in its free position. Then the runner 1, now released, is pushed forward against the said object by the compression spring 13 until the catch connected to the runner goes against the edge of the object. When the operating knob 11 of the bar 4 is then released, the torsion spring 12 will turn the bar and hence the washer until the washer is in its pinch position, and the runner 1 and hence the catch are again locked to the bar. The catch can then trigger the stapling stroke of the electric stapler. If, instead, it is desired to increase the stapling depth, the object to be stapled is first inserted into the stapler until it bears against the catch and then the bar 4 is turned by the operating knob 11 until the washer is in its free position. The runner 1, now released, and thus the catch are then pushed back along the bar 4 by means of said object until the desired stapling depth is achieved. When the operating knob 11 of the bar 4 is then released, the bar and hence the washer are turned by the torsion spring 12 until the washer 6 is in its pinch position, and the runner 1 and hence the catch are again locked to the bar. The catch can then trigger the stapling stroke of
It will be appreciated that the invention is not limited to the embodiment described above and illustrated in the drawings, but can be modified in different ways within the scope of the appended claims,