US3784187A

US3784187A - Folding apparatus

Info

Publication number: US3784187A
Application number: US00102341A
Authority: US
Inventors: S Takayanagi; T Nimoda
Original assignee: Mitsubishi Heavy Industries Ltd
Current assignee: Mitsubishi Heavy Industries Ltd
Priority date: 1970-01-14
Filing date: 1970-12-29
Publication date: 1974-01-08
Anticipated expiration: 1991-01-08
Also published as: JPS5019971B1; GB1299332A

Abstract

A web transferring, cutting and folding apparatus shiftable between two modes of operation for producing from a continuous web, either two streams of eight page sections or one stream of 16 page sections. In the first mode, two triangular formers double and redouble the web about its longitudinal axis. Then it is cut into single width, double length and finally single width, single length eight page sections which are alternately forwarded to separate streams. In the second mode, one triangular former doubles the web about its longitudinal axis. Then it is cut into double length, double width sections which are next folded into single length double width sections transversally and forwarded in one stream to a right angle folding unit which folds these sections about the longitudinal axis into single length, single width 16 page sections. In shifting between the two modes, most of the apparatus is relatively rotated 90* to alternatively utilize or by pass the one of the two triangular formers.

Description

nite ttesl te Takayanagi et al.

r451 Jan.a,1974

[ 4] FOLDING APPARATUS Mitsubishi Jukogyo Kabushiki Kaisha, Tokyo, Japan [22] Filed: Dec. 29, 1970 [21] Appl. No.: 102,341

[73] Assignee:

Foreign Application Priority Data FOREIGN PATENTS OR APPLICATIONS 1,204,689 11/1965 Germany 270/63 Primary Examiner-Robert W. Michell Assistant Examiner-L. R. Oremland Att0rney-Cushman, Darby & Cushman [5 7] ABSTRACT A web transferring, cutting and folding apparatus shiftable between two modes of operation for producing from a continuous web, either two streams of eight page sections or one stream of 16 page sections. In the first mode, two triangular formers double and redouble the web about its longitudinal axis. Then it is cut into single width, double length and finally single width, single length eight page sections which are alternately forwarded to separate streams. In the second mode, one triangular former doubles the web about its longitudinal axis. Then it is cut into double length, double width sections which are next folded into sin gle length double width sections transversally and forwarded in one stream to a right angle folding unit which folds these sections about the longitudinal axis into single length, single width 16 page sections/1n shifting between the two modes, most of the apparatus is relatively rotated 90 to alternatively utilize or by pass the one of the two triangular formers.

2 Claims, 4 Drawing Figures Pmmew 8:914 3.784.187

SHEE! 2 (l? 2 INVENTORS ATTORNEYS FOLDING APPARATUS FIELD or THE INVENTION This invention relates to a folding apparatus for folding the web which is continuously printed as by a rotary press and discharged out to be folded, and more specifically to improvements of folding apparatus. which make it possible to obtain 8- and l6-page sections on a single folder unit.

BACKGROUND OF THE INVENTION With an ordinary folding apparatus of this type it is necessary to use a low speed for conveying the sections, or a low machine speed, if the sections are to be finished. within the allowance for folding accuracy ($1.0 1.5 mm) as required by the subsequent bookbinding process.

The sections which are carried by conveying means through triangular formers, serrated cutters and folding cylinders, undergo complicate changes in the posture and direction as a brake is applied thereon by the tips of choppers which move the sections up and down thereby folding themat right angles in the course of conveyance, and also because the sections are caused to hit stoppers provided at the end of the right angle folding apparatus for the purpose of stoppng the sections to be subjected to right angle folding. As a result,

the right-angled folding lines are randomly changed with individual sections and the right angle folding accuracy is unfavorably affected, Therefore, if the folding accuracy on an existing apparatus is to be maintained within the specified limits, then the speed at which the machine runs must be kept low, thus posing a produc-. tivity problem. It is also noted that, while a common practice in the art has been to fold printed paper first into two or 4 pages by a traingular former, and then into two or 8 pages by a parallel folder, and finally into two or 16 pages by a right-angled to folder, a recent tendency is a steady increase in demand for multi-color S-page sections due to growing popularity of multicolor high grade printing by rotary presses. However, no practical folder has been introduced yet that meets the latter requirementand a makeshift practice being resorted to is to divide the l6-page sections obtained in the conventional way into two 8-page sections by hand. This is a disadvantage because it needs much manual labor and consumes much of the valuable time for the publications, particularly weekly magazines, which must go off the press as promptly as possible for distribution in time.

This invention resides in a folding apparatus comprising a first triangular former, a second triangular former provided downstream of the first triangular former and alongside the path of the web, in the direction to cross the first triangular former, a folding cylinder disposed at right angles to the path of the web downstream of the second triangular former and which has serration receivers, needles, and folding blades operation for obtaining 8-page sections, a first serrated cutter having serrations which is located parallelly alog one side of the folding cylinder, a second serrated cutter having needles and serrations in vertically spaced relationship and which is located parallelly along the other side of the folding cylinder, a gripping cylinder having needles and grippers for obtaining 8-page sections, two sets each of section conveyors engaged with the second serrated cutter and the gripping cylinder, and a housing which supports the folding cylinder, first and second serrated cutters, gripping cylinder and two conveyors and which is. installed turnably at certain angles with respect to the path of the web. The object of the invention is to provide a folding apparatus of an extremely simplified construction which is free from the disadvantages of the conventional arrangements, in which two tiangular formers and two serrated cutters are provided and the housing that supports the serrated cutters, folding cylinders, gripping cylinder, etc. can be turned as a whole at certain angles. 8

According to the present invention, as above stated, the first triangular former and the second triangular former crossing the same are arranged along the path of the web that comes out as from a rotary press, the

, second serrated cutter is located on the other side of the folding cylinder, the housing is made turnable at certain angles with respect to the path of the web, and the folding blades of the folding cylinder andthe grippers of the gripping cylinder are designed so that their operations can be stopped as desired. This folderconstruction enables the web to be folded into 8 pages as it simply passes along the first and second triangular formers. The folded paper is then led by way of the first serrated cutter and the folding cylinder simultaneously on two, lines, i.e., one line consisting of the second serrated cutter and the associated conveyor, and the other line consisting of the gripping cylinder and the associated conveyor, to be delivered out as 8-page sections.

Thus it is not necessary, as on a conventional apparatus, to convey prefolded sections accurately and orderly to a preset point of the right-angled folder installed on the path of conveyance of the sections. This means that the speed at which the sections are conveyed, or the machine speed, need not be low. The web is folded exactly by the tension of the running paper itself as it passesalong the first and second triangular formers. Moreover, because the advancing direction of .the web is changed by turning the folding apparatus itself at a certain angle from the given position, the turn bar or the like which is customarily used to alter the path of the webcan be dispensed with and hence any staining of the printed surface or meandering of the web across its width is avoided. Thus, in conformity with the present invention, S-page sections can be obtained accurately at a high speed. The simultaneous delivery of the sections in two lines, furthermore, helps the apparatus attain a high efficiency.

Since the second serrated cutter is supported by an eccentric bearing in such a manner that it can be moved into and out of contact with the folding cylinder, the folding apparatus according to this invention can produce l6-page sections just as by ordinary folders. For that purpose the apparatus as a whole is turned to a position at a right angle to the path of the web, and the second serrated cutter is disengaged from the folding cylinder so that the transfer of sections to the cutter is discontinued while, at the same time, the web is passed along the first triangular former. With such an extremely simple operation, l6-page sections can be formed on a single unit of folding apparatus. Thus, the present invention has great practical advantages in that it permits folding of paper into sections as desired with a limited initial investment and a minimum of labor.

FIG. 1 is a diagrammatic view explanatory of an embodiment of this invention;

FIGS. 2 and 3 are perspective views illustrating the relative positions of first and second triangular formers and folding arrangement in operation, FIG. 2 showing the folding arrangement located normal to the direction in which web is fed to produce the same sections as by a conventional arrangement, and

FIG. 3 showing the same folding arrangement of FIG. 2 turned at an angle of 90 from the position of FIG. 2; and

FIG. 4 is a schematic view explanatory of the operating principles of the embodiment.

The present invention will be better understood from the following detailed description taken in conjunction with the accompanying drawings showing an embodiment thereof. In FIG. 1, a first triangular former 1 is shown located at the leading end of web in the same way as in a conventional folding apparatus. The web runs, by its own tension, along the triangular former l and the front end portion is continuously folded into two. A second triangular former 2, generally of the same construction as the first triangular former l, is located therebelow in such a position as to cross the first triangular former l substantially at right angles thereto. In the manner to be described later, the web folded by the first triangular former 1 is again folded into two as it passes along the second triangular former 2. The web thus reduced to about a quarter of the original width is fed downward. Groups of nip rollers 3, 3 are arranged, respectively, below the firs and second triangular formers 1, 2. They pull the web downstream of the triangular formers 1, 2 so as to give tension to the web and also set the folds of the web already folded by the triangular formers.

Numeral 4 denotes a serrated cutter of a known design equipped with serrations 11 on the circumference and which constitutes a first serrated cutter. Numeral 5 designates a folding cylinder which, like an ordinary folding cylinder, carries on the circumference first and second serration receivers 6, 9, needles 7 and folding blades 8, in such a manner that needles 7 and folding blades 8 can be urged out or into the cylinder body by suitable cam means.

A serrated cutter 10 to constitute a second serrated cutter is provided with serrations 11 and needles 7' which can be urged out or into the cylinder body by suitable cam means. This secon serrated cutter is attached to the housing 21 engageably with the folding cylinder 5 in the manner to be described later. As spindle 12 for the second serrated cutter 10 is borne by an eccentric bearing 13, so that the second serrated cutter 10 can be moved inot or out of contact with the folding cylinder 5 by the combined action of a pressure-fluid cylinde 14 and a connecting rod 15 interposed between the eccentric bearing 13 and the housing.

A gripping cylinder 16 has on the circumference grippers 17 of the known type as well as needles 7" similar to the needles 7, 7' which are provided, respectively, on the circumferences of the folding cylinder 5 and the second serrated cutter 10 in such a manner as to come out or into the respective cylinder bodies. Two pairs of conveyors I8, 19 are extended to regions above the second serrated cutter 10 and the gripping cylinder 16, respectively. Each pair holds and carries the 8-page sections formed by the preceding cylinders toward sub.- sequent stations. A right-angle folding unit 20 of a known design is disposed on the path of the conveyor 19. A pivotal shaft 22 is provided for the housing 21 of 4 the folding apparatus that supports the components above described. Shown at 23 is a bearing and at 24 is a toothed wheel formed on the underside of the housing 21. The toothed wheel 24 is in mesh with a toothed wheel 26 adapted to be driven by a motor 25 installed on the floor. Instead of these toothed wheels 24, 26, a power transmission mechanism of chain-sprocket type may be employed. Rollers 27 secured to the underside of the housing 21 bear the total weight of the folding apparatus and also serve to guide the turning of the apparatus in the way to be described later. Although in this embodiment the second serrated cutter 10 is brought into and out of engagement with the folding cyliner 5 by means of the pressure-fluid cylinder 14 which causes rotation of the eccentric bearing, the cylinder 14 may be replaced by a gear driving mechanism having gear in mesh with a gear in place of the eccentric bearing (13).

MODE FOR PRODUCING TWO STREAMS OF EIGHT PAGE SECTIONS The operation of the embodiment constructed in the manner so far described will now be explained with reference to FIGS. 3 and 4. i

Web end that comes out of a rotary press (not shown) is, in the first place, folded into two by the first triangular former 1 and is guided by hand to the second triangular former 2 thereby to be again folded into two, and then is led to the nip between the first serrated cutter 4 and the folding cylinder 5. Once the web end has been threaded in this way into the nip between the first serrated cutter 4 and the folding cylinder 5, the web automatically passes along the first and second triangular formers 1, 2 and through the nip between the first serrated cutter 4 and the folding cylinder 5'where it is cut off through the co-operation of serration 11 on serrated cutter 4 and serration receiver 6 on folding cylinder 5, and at the same time, the cut leading edge is caught by the needles 7 on the folding cylinder 5. Thus, web is fed along the surface of the folding cylinder 5 and as the folding cylinder 5 totates, the cutting operation and feeding of the web are continuously repeated. Therefore, serrations l1, and serration receivers 6 and needles 7 are so arranged on the serration cutter 4 and on the folding cylinder 5v that they meet cooperatively.

When the middle line of the cut web, carried by the needles 7 with the folding cylinder 5, having 8-pages and being two-times longer than the finally expected products, comes to the nip between folding cylinder and 2nd serrated cutter, it is cut off into two sections through the co-operation of the serration 11 on the second serrated cutter l0 and the serration receiver 9. In this case, also, the leading edge of the trailing section is caught by the needles 7, on the second serrated cutter 10. The serrations 11, and needles 7', and serration receivers 9 are soarranged on the 2nd serration cutter 10 and the folding cylinder 5 that the meet cooperatively. The preceding section is yet carried by the needles 7 on folding cylinder 5 and when its leading edges comes to the nip between the folding cylinder 5 and the gripping cylinder 16, the needles 7 are urged into the folding cylinder 5 by the same means and at the same time the needles 7" are urged out of the gripping cylinder 16 and catch the the sections. Thus, the preceding sections, having 8 -pages and desired size, are delivered via gripping cylinder 16 and conveyor 19.

On the other hand, the trailing sections are having 8- pages and desired size, are delivered via the second serration cutter l and the conveyor 18.

The positions of the needles 7' and serrations 11 on the second serrated cutter l0 and the matching positions of the serrations receivers 9 on the folding cylinder that correspond to the serrations 1 l, and also the operative relations between the needles 7' and serrations 1 1' are prearranged by adjusting the relative positions of the folding cylinder 5, gripping cylinder 16 and second serrated cutter 10, controlling the operation timing and the actuation of cams not shown in order housing 21 of the embodiment above described is capable. of being'turned at'an angle of 90 with respect to that the slitted paper caught by the needles 7 of the tracted by suitable cam means (not shown).

MODE FOR PRODUCING ONE STREAM OF 16 PAGE SECTIONS As already stated, the second serrated cutter of the embodiment is built engageably with the folding cylinder 5, and the folding apparatus as a unit can be turned at an angle of 90 from a given position because the housing2l is turnable itself. This construction not merely permits production of 8-page sections in two lines but, in addition, renders it possible to obtain 16- page sections where necessary in the same fashion as on a conventional equipment. The operation for the latter case will be briefly explained hereunder in conjunction with FIGS. 2 and 4. First, the housing 2l'is turned 90 about the pivotal shaft 22 in the direction indicated by an arrow A in FIG. 2, to a position normal to the direction wherein the web is being introduced. At the same time, the second serrated cutter 10 is disengaged from the folding cylinder 5 to the position indicated by an alternate long and two short dashes line in FIG. 4. Following this, the web is led from the first triangular former 1 directly into the nip between the folding cylinder 5 and the first serrated cutter 4, by-

passing the second triangular former 2, and the web is thereby allowed to be automatically fed from the rotary press. It is then possible to obtain-l-page sections in much the same way as with a conventional equipment. In this case, of course, the folding blades 8 on the folding cylinder 5 are caused to function, while the needles 7" on the gripping cylinder 16 are kept inoperative that is, when the middle line of the cut web, carried by the needles 7 with the folding cylinder 5, having 4-page and two-times longerand wider than finally expected products, comes to the nip between folding cylinder 5 and gripping cylinder 16, the folding blade 8 urges out of the cylinder surface and through the co-operation of this folding blade 8 and gripper 17, the cut web is gripped by the gripper 17, being folded into half and carried via gripping cylinder 16 and conveyor 19 to the right-angle folder 20, where the section is subjected to right-angle fold, thus being produced l6-page section. The right-angle folding unit 20 may be shifted for use according to the necessity. As explained in connection with this embodiment, the folding apparatus of this invention makes it possible to obtain 8 -page sections simultaneously in two rows on a single machine and also obtain, if necessary, l6-page sections as on ordinary apparatus, thus attaining high productivity and economy of labor with low initial investment to excellent practical advantage. It is to be added that, although the the path of the web, the housing 21 is not always required to be turnable at the angle of Thus the rnachine disclosed herein has two modes of operation: one is explained in the specification with reference to FIG. 2 and the other is explained with reference to FIG. 3. The machine itself is best understood from FIG. 1. Some of the elements of the machine, such as the folding cylinder and the rightangle folding units are individually per se conventional. Their structure and usual operation are well known to those skilled in the art. Accordingly, the explaination of this specification identifies these elements (b) explains how they are organized in combination and (c) concentrates on what differs from that which are skilled in the art would normally expect. r

In the first mode of operation, explained with respect to Fig. 3 the incoming web is manufactured into twice as many eight page sections of the same page size as the 16 page sections produced when operating in thesec- 0nd mode explained with respect to FIG. 2.

In brief, when operating in the FIG. 3 mode: the former 1 doubles the web over about its longitudinal axis and the former 2 doubles the resulting webs about its longitudinal axis to produce a continuous web for thicknesses thick (i.e., of 8 pages, it being usual in this industry to count the two sides of each thickness as individual pages). In this mode, the folding cylinder 5 does not fold anything, because its folding arms 8 are kept inoperative. Instead, the first serrated cutter 4 cuts the twice longitudinally folded web transversally into segments whichare each twiceas long as the intended eight page sections. Then the second serrated cutter it) cuts each of these segments transversally into two eight page sections. Every other one of these eight page sections is carried away by the conveyor 19. and alternate ones are carried-away by the conveyor 18. The right angle folding units 20 are not operated in this mode either.

When operating the machine in the FIG. 2. mode, the whole of the apparatus (but for the two formers l and 2 and the nip rolls 3) is rotated 90 about the axis 22. This causes'the former 2 to be bypassed. Accordingly, the former 1 doubles the web over about its longitudinal axis to produce a continuous web two thicknesses thich (i.e., of 4 pages). The second serrated cutter 10 is retracted at 14, 15 to a position of inoperativeness. The first serrated cutter, as before, cuts the once longitudinally folded web transversally into segments which are each twice as loud and twice as wide as intended 16 page sections. In this mode, the folding cylinder 5 does fold: the arms 8 conventionally fold each segment transversally into an eight page semi-finished product as long as, but twice as wide as the intended product. Since the element 10 is sidelined, all the semi-finished product is carried to the conveyor 19. In this mode the conventional right angle folding unit 20 does operate: it folds each segment longitudinally into a 16 page section.

What is claimed is:

1. Apparatus for selectively manufacturing either two streams of eight page sections in a first mode of operation or one stream of vl6 page sections in a second mode of operation, from a continuous web of paper,

- said apparatus comprising:

means for forwarding the web along a path;

a first triangular former positioned to interceptthe web and double the web about the longituidnal axis thereof;

a second triangular former positioned downstream of the first triangular former and oriented at a substantial angular disparity with respect thereto to intercept the once doubled web, only when said apparatus is operating in the first mode thereof, for redoubling the once doubled web about the longitudinal axis thereof;

a rotating transfer roll contiguous with said path,

downstream of said second triangular former, means on the rotating transfer roll for temporarily grasping the web, regardless of whether the web has been doubled once or twice, and for carrying what has been grasped, on the periphery thereof, throughout somewhat short of a complete revolution of the rotating transfer roll;

first serration means intermittently cooperable with the rotating transfer roll shortly downstream of where the web is grasped thereon by said grasping means, for transversally servicing the web, regardless of whether the web has been doubled once or twice, into segments each twice as long as the page sections to be produced;

second serration means, intermittently cooperable wtih the rotating transfer roll angularly downstream of where the web is served with the first serration means, for tranversally severing each of said segments into two eight page sections only when said apparatus is operating in the first mode thereof;

a rotating gripper cylinder contiguous with said path angularly downstream of where the second serration means severs each of the segments into two eight page sections when the apparatus is operating in the first mode thereof;

a first conveyor disposed to receive angularly trailing ones of said eight page sections from said second serration means; means on said second serration means for removing said angularly trailing ones of said eight page sections from saie rotating transfer roll and for depositing the sections so removed with the first conveyor to provide one of said two streams of eight page sections;

a second conveyor disposed to receive angularly leading ones of said eight page sections from said gripper cylinder; means on said rotation gripper cylinder for removing said angularly leading ones of said eight page sections from said rotating transfer roll and for depositing the sections so removed with the second conveyor to provide the other of said two streams of eight page sections;

means for withdrawing the second serration means from cooperation with the rotating transfer cylinder, so that when the apparatus is operating in the second mode thereof the once doubled web remains severed into segments each twice as long and twice as wide as the 16 page sections to be produced while being carried by the rotating transfer roll and the first conveyor is thus isolated from the rotating transfer roll and receives no sections;

transverse folding blade means on the rotating transfer roll, structured, positioned and operable only when the apparatus is operating in the second mode thereof to double-over each segment transversally while each segment is being carried by the rotating transfer roll to provide segments each as wide but still twice as long as the 16 page sections to be produced;

and right angle folding unit means associated with the second conveyor for doubling over each segment longitudinally to provide said 16 page segments from the last-mentioned segments transfered to the second conveyor from the rotating transfer roll by the rotating gripping cylinder;

and means for angularly shifting the orientation of the once doubled web with respect to the periphery of the transfer cylinder about the longitudinal axis of the web to accomodate said path to whether the second triangular former is to be used (in the first mode) or bypassed (in the second mode);

said rotating transfer roll, said first serration means, said second serration means, said rotating gripper cylinder, said first conveyor and said second conveyor all being mounted on said shifting means, whereby, but for extension and withdrawal of the second serration means and rendering said transverse folding blade means operative and inoperative, switching said apparatus from operating in said first mode to operating in said second mode, and vice versa is substantially accomplished by shifting said shifting means through the amount of said angular disparity.

2. The apparatus of claim 3 wherein said angular dis-

Claims

1. Apparatus for selectively manufacturing either two streams of eight page sections in a first mode of operation or one stream of 16 page sections in a second mode of operation, from a continuous web of paper, said apparatus comprising: means for forwarding the web along a path; a first triangular former positioned to intercept the web and double the web about the longituidnal axis thereof; a second triangular former positioned downstream of the first triangular former and oriented at a substantial angular disparity with respect thereto to intercept the once doubled web, only when said apparatus is operating in the first mode thereof, for redoubling the once doubled web about the longitudinal axis thereof; a rotating transfer roll contiguous with said path, downstream of said second triangular former, means on the rotating transfer roll for temporarily grasping the web, regardless of whether the web has been doubled once or twice, and for carrying what has been grasped, on the periphery thereof, throughout somewhat short of a complete revolution of the rotating transfer roll; first serration means intermittently cooperable with the rotating transfer roll shortly downstream of where the web is grasped thereon by said grasping means, for transversally servicing the web, regardless of whether the web has been doubled once or twice, into segments each twice as long as the page sections to be produced; second serration means, interMittently cooperable wtih the rotating transfer roll angularly downstream of where the web is served with the first serration means, for tranversally severing each of said segments into two eight page sections only when said apparatus is operating in the first mode thereof; a rotating gripper cylinder contiguous with said path angularly downstream of where the second serration means severs each of the segments into two eight page sections when the apparatus is operating in the first mode thereof; a first conveyor disposed to receive angularly trailing ones of said eight page sections from said second serration means; means on said second serration means for removing said angularly trailing ones of said eight page sections from saie rotating transfer roll and for depositing the sections so removed with the first conveyor to provide one of said two streams of eight page sections; a second conveyor disposed to receive angularly leading ones of said eight page sections from said gripper cylinder; means on said rotation gripper cylinder for removing said angularly leading ones of said eight page sections from said rotating transfer roll and for depositing the sections so removed with the second conveyor to provide the other of said two streams of eight page sections; means for withdrawing the second serration means from cooperation with the rotating transfer cylinder, so that when the apparatus is operating in the second mode thereof the once doubled web remains severed into segments each twice as long and twice as wide as the 16 page sections to be produced while being carried by the rotating transfer roll and the first conveyor is thus isolated from the rotating transfer roll and receives no sections; transverse folding blade means on the rotating transfer roll, structured, positioned and operable only when the apparatus is operating in the second mode thereof to double-over each segment transversally while each segment is being carried by the rotating transfer roll to provide segments each as wide but still twice as long as the 16 page sections to be produced; and right angle folding unit means associated with the second conveyor for doubling over each segment longitudinally to provide said 16 page segments from the last-mentioned segments transfered to the second conveyor from the rotating transfer roll by the rotating gripping cylinder; and means for angularly shifting the orientation of the once doubled web with respect to the periphery of the transfer cylinder about the longitudinal axis of the web to accomodate said path to whether the second triangular former is to be used (in the first mode) or bypassed (in the second mode); said rotating transfer roll, said first serration means, said second serration means, said rotating gripper cylinder, said first conveyor and said second conveyor all being mounted on said shifting means, whereby, but for extension and withdrawal of the second serration means and rendering said transverse folding blade means operative and inoperative, switching said apparatus from operating in said first mode to operating in said second mode, and vice versa is substantially accomplished by shifting said shifting means through the amount of said angular disparity.

2. The apparatus of claim 3 wherein said angular disparity is 90* and the shifting means is constituted by a mobile housing shiftable through 900*.