Conveyor apparatus, especially for printed products

An article conveyor apparatus is disclosed wherein the gripper clamps possess a movable clamping tongue and a fixed clamping tongue which forms part of a housing. The movable clamping tongue is formed of one-piece with a spiral spring. The latter is wound about a hollow shaft rotatably mounted in the housing. The hollow shaft is rigidly connected for rotation with an arm or lever carrying at its end a roller. A part of the hollow shaft is constructed as a blocking wheel of a blocking mechanism. This blocking wheel is provided with a gap into which engages, in the latching position, the one end of a blocking pawl pivotably mounted in the housing. Upon travel of the roller upon a bracket or cam or the like the hollow shaft is rotated in a predetermined direction, whereby the movable clamping tongue is moved towards the other clamping tongue. If both clamping tongues are brought together then during further rotation of the hollow shaft the spiral spring is tensioned. The tensioned spiral spring exerts a closing force upon the movable clamping tongue. Retrorotation of the hollow shaft is prevented by the blocking pawl which has latched into the gap. To open the gripper clamp the blocking pawl of the blocking arrangement is released by depressing upon a part protruding past the housing. The now relaxed spiral spring rotates the hollow shaft in another predetermined direction, so that the movable clamping tongue is raised from the stationary clamping tongue. The spiral spring therefore serves both as a closing spring and also as an opening spring for the clamping tongues and also as a holder spring for the blocking mechanism.

BACKGROUND OF THE INVENTION 
The present invention relates to a new and improved construction of a 
conveyor apparatus, especially for printed products. 
Generally speaking, the article conveying apparatus of the present 
development is of the type comprising gripper clamps anchored in spaced 
relationship from one another at a revolving traction or tension element. 
The one movable clamp portion is brought into a closed position by means 
of an actuation element which coacts with a stationary control device and 
it is retained in such closed position by a releasable locking device. 
With such type prior art conveyor apparatus the movable clamp portion is 
attached to a guide bolt which is displaceably guided in its axial 
direction within the gripper housing against the action of a compression 
or pressure spring. Significant in this regard is German Patent 
Publication No. 2,519,561 and U.S. Pat. No. 3,955,667. In the closed 
position the guide bolt, and thus, the movable clamp portion is locked by 
means of a releasable clamp lock which bears against the guide bolt and 
arrests the same. The closed position of the movable clamp or clamping 
portion is not exactly defined and depends upon the thickness of the 
seized product. To render possible a faultless grasping of products of any 
random thickness, both of the clamp portions must possess an appropriately 
long length. This results in the lever arm of the closing force acting 
upon the guide bolt becoming correspondingly longer. This leads, in turn, 
to the fact that the guide bolt can cant, something which impairs both the 
proper closing operation and also an immediate opening of the gripper. A 
faultless clamping of the seized products and a faultless opening at the 
desired site therefore is not ensured for with such construction. 
Additionally, the closed position which is governed by the thickness of 
the seized product does not satisfactorily take into account the 
requirement that thicker products, because of their usually greater 
weight, must be retained with a larger clamping force than thin products. 
SUMMARY OF THE INVENTION 
Therefore with the foregoing in mind it is a primary object of the present 
invention to overcome the aforementioned drawbacks and limitations of the 
prior art constructions. 
Another and more specific object of the present invention aims at providing 
a new and improved construction of an article conveyor apparatus of the 
previously mentioned type which allows for a faultless seizing and 
retention of articles, such as typically for instance by way of example 
and not limitation printed products, of different thickness and equally 
enables an instantaneous release of such seized articles. 
Yet a further significant object of the present invention aims at providing 
a new and improved construction of an article conveyor apparatus which is 
relatively simple in construction and design, economical to manufacture, 
extremely reliable in operation, not readily subject to breakdown or 
malfunction, and requires a minimum of maintenance and servicing. 
Now in order to implement these and still further objects of the invention, 
which will become more readily apparent as the description proceeds, the 
conveyor apparatus of the present development is manifested by the 
features that the locking device is constructed as a latching device 
having a defined latching position. The actuation element is operatively 
coupled with the latchable element of the latching device and such 
actuation element is connected with the aforementioned movable clamp or 
clamping portion by means of a spring element which is tensioned when the 
gripper clamp is closed. 
The spring element which is arranged between the actuation element causing 
closing of the gripper clamp and the movable clamp portion is tensioned 
during the course of the closing operation and exerts upon such clamp 
portion a closing force. Additionally, this tensioned spring element 
ensures for a locking of the latching device. The spring element therefore 
serves both as a closing spring for the gripper clamp and also as a holder 
spring for the latching device. Moreover, the spring element also assumes 
the function of an opening spring. If, namely, the latching device is 
released, then the movable clamp portion is raised from the other 
stationary or fixed clamp portion by the action of the relaxing spring 
element, so that there is possible an immediate release of the seized 
article or the like. Since the latching position is exactly defined, the 
spring element is more intensely tensioned in the presence of thick 
articles than in the case of thin articles, leading to a desired greater 
clamping force when handling thick articles.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Describing now the drawings, in FIG. 1 there is illustrated part of the 
conveyor device 1 at the transfer or take-over section for the articles 
being handled, here assumed to be printed products 2. These printed 
products 2 lie in outwardly open, radial compartments 4 of an only 
partially illustrated but known revolving cell wheel 3. The construction 
and mode of operation of such cell wheel, as stated, is known and has been 
described in detail for instance in German Pat. No. 2,447,336 and the 
corresponding U.S. Pat. No. 3,951,399 and German Pat. No. 2,604,104 and 
the corresponding U.S. Pat. No. 4,058,202, to which reference may be 
readily had and the disclosure of which is incorporated herein by 
reference. The printed products 2 bear by means of their fold 2a at the 
base or floor of the compartments 4. The conveyor device 1 will be seen to 
contain grippers or gripper clamps 5 for seizing and transporting the 
printed products 2. These grippers 5 each contain a movable gripper clamp 
tongue 6 and a counter-gripper clamp tongue 7 coacting with the movable 
clamp or clamping tongue 6. The construction of such grippers or gripper 
clamps 5 will be described in greater detail in conjunction with FIGS. 2 
to 6. These gripper clamps 5 are attached in spaced relationship from one 
another at a suitable revolving traction or tension element 8 which, for 
instance, can be constructed as a ball-and-socket joint-link chain, such 
as has been described in British Pat. No. 1,549,383 and the corresponding 
German Patent Publication No. 2,629,528 as well as the copending United 
States application Ser. No. 867,027, filed Jan. 5, 1978, now U.S. Pat. No. 
4,294,345, granted Oct. 13, 1981, to which reference may be likewise 
readily had and the disclosure of which is equally incorporated herein by 
reference. This traction element 8 travels in a closed guide channel 9, as 
best seen by referring to FIG. 3, which is provided at its underside with 
a longitudinal or lengthwise extending slot 9a. As particularly well seen 
by referring to FIG. 1, this traction element 8 is trained about a 
deflection wheel 10 or the like which rotates in the direction of the 
arrow A, i.e. in the transport direction. In order to close the gripper 
clamps 5 there is provided a stationary bracket or cam arrangement 11 or 
equivalent structure. 
Based upon the illustration of FIGS. 2 to 6 there will now be explained in 
detail the construction of the gripper clamps 5 and their attachment at 
the traction element 8. 
As best seen by referring to FIG. 3, there are secured at the traction 
element 8 at a relatively uniform spacing from one another arms or arm 
members 12 which extend towards the side, the gripper clamps or grippers 5 
being seated upon such arm members. These arm members 12 engage into an 
opening provided in a gripper housing 13. By means of a securing pin 14 
which pierces the related arm 12, and which securing pin 14 is 
accommodated in a throughpass opening 15 in the gripper housing 13, the 
grippers or gripper clamps 5 are retained at the related arm or arm member 
12, as best seen by referring to FIG. 5. As particularly well recognised 
by inspecting FIGS. 2 and 5, the stationary or fixed clamp tongue 7 is 
constructed to constitute part of the housing 13. At its ends both of the 
clamp tongues 6 and 7 are provided with a rubber bellows 16 or the like, 
which, on the one hand, protects the seized printed product 2 or other 
engaged article against damage and, on the other hand, increases the 
static friction between the clamping tongues 6, 7 and the printed product 
2. 
The movable clamping tongue 6 consists of a spring steel and is formed of 
one-piece with a spiral spring 17 merging at its rear end. This spiral 
spring 17 is wound about a hollow shaft 18 which is rotatably mounted in 
the housing 13. This hollow shaft 18 possesses a square or four-cornered 
portion 18a (FIG. 5) over which there is guided the spiral spring 17. In 
this way there is obtained a good connection between the shaft 18 and the 
spiral spring 17. The hollow shaft 18 which extends through the housing 13 
is secured at one end by means of a securing ring 19 or equivalent 
structure and is rigidly connected at its other opposite end with a lever 
20, as best seen by referring to FIG. 4. This lever or lever member 20 
carries at its free end a roll or roller 21, as particularly evident by 
inspecting FIG. 2. 
Seated upon the hollow shaft 18 is a blocking wheel 22 of a pawl blocking 
arrangement, as shown in FIGS. 4 and 5. In the exemplary embodiment under 
discussion this blocking wheel 22 is constructed as part of the hollow 
shaft 18. As best seen by referring to FIG. 5, this blocking wheel 22 is 
provided with a gap 23 into which engages, in the latching position, the 
front end 24a of a blocking pawl 24. The other end 24b of the blocking 
pawl 24 protrudes past the housing 13. The blocking pawl 24 is rotatably 
seated upon an axle or shaft 25 which piercingly extends through the 
housing 13 and is retained therein. The one end 25a of the axle or shaft 
25 is offset for this purpose and carries at the outer side of the housing 
13 a securing ring 26 or the like, as shown particularly well in FIG. 4. 
Upon this axle or shaft 25 there is arranged a leg spring 27, whose one 
leg 27a engages at the blocking pawl 24 and whose other end or leg 27b is 
supported at the housing 13. By means of this leg spring 27 the blocking 
pawl 24 is pressed at its end 24a against the blocking wheel 22 and into 
the gap 23. As an equivalent structure to the gap 23 it is possible to 
provide at the blocking wheel 22 also a tooth at which engages the end 24a 
of the blocking pawl 24 in the latching position. 
As will be seen by inspecting FIG. 4 and, in particular, FIG. 6, there is 
wound about the square portion or section 18a of the hollow shaft 18 a 
further spiral spring 28 which is connected at one end with the shaft 18 
and at the other end 28a braces against the shaft or axle 25. This spiral 
spring 28 serves the purpose of retaining in an open condition the gripper 
clamps 5 during their movement from the delivery region to the transfer or 
take-over region. However, under circumstances it would be possible to 
dispense with the use of this spring 28. 
At the delivery or outfeed region there is arranged an opening device for 
opening the gripper clamps 5. This opening device, as best seen by 
referring to FIG. 2, contains a control roller or roll 29 which can be 
raised and lowered in the direction of the double-headed arrow C, by means 
of a suitable actuation or displacement device, here shown as a 
pressurised cylinder unit 30. The control roller or roll 29 serves to rock 
the blocking pawl 24 in the direction of the arrow D, in order to thereby 
release the pawl blocking arrangement. 
The mode of operation of the described conveyor device 1 will now be 
considered and is as follows: 
As will be evident by inspecting FIG. 1, the gripper clamps 5 arrive in an 
opened condition at the transfer region. As already explained, there can 
be provided for the purpose of retaining open the clamp tongues or jaws 
6,7 the spring 28. Yet it is also possible, as explained, to dispense with 
the use of this spring 28 and instead to provide a bracket or cam 
arrangement directly in front of the transfer region, which causes by 
means of the roller 21 travelling thereon a rocking or pivoting of the 
movable clamping tongue or jaw 6 into its open position. Between both of 
the clamping tongues 6 and 7 there now arrives the printed product 2 which 
is to be seized. With the illustrated exemplary embodiment the printed 
products 2 are engaged at the region of their open side 2b (the so-called 
cut side or flower). During the course of the further movement in the 
direction of the arrow A the roller 21 travels on to the bracket or cam 
11. The latter then causes, by means of the action of the lever 21, 
rotation of the hollow shaft 18 in the direction of the arrow B shown in 
FIGS. 2, 5 and 6. Consequently, the movable clamping tongue 6 is moved 
towards the stationary clamping tongue 7, and the printed product 2 is 
fixedly retained between both of the clamping tongues 6 and 7. As soon as 
the clamping tongues 6 and 7, while pressing together the seized printed 
product 2, are brought together and a further pivoting of the movable 
clamping tongue 6 is no longer possible, then during the further rotation 
of the hollow shaft 18 the spiral spring 17 and also the spiral spring 28 
are tensioned. This tensioning of the springs 17 and 28 or equivalent 
structure is terminated at that point in time when the end 24a of the 
blocking pawl 24 engages into the gap 23 of the blocking wheel 22. Due to 
the latching of the blocking pawl 24 into the gap 23 there is prevented 
any rotation back of the hollow shaft 18 by the action of the biased or 
tensioned springs 17 and 28. The spiral spring 17 now exerts a clamping 
force corresponding to its tension or bias upon the clamping tongue or jaw 
6. Additionally, the spiral spring 17 serves as a holder or retention 
spring for the blocking mechanism 22, 23, 24 which is located in its 
latched position. Since the latching position is exactly defined by the 
position of the gap 23 and always remains the same, there is achieved the 
beneficial result that the tensioning of the spiral spring 17 with closed 
gripper clamp 5 and thus also the closing force exerted thereby at the 
clamping tongue 6 is greater when handling thick products than in the case 
of thin products. The thick products 2 which, as a general rule, are also 
heavier are therefore retained with a greater clamping force than the thin 
products. In this way it is possible to always faultlessly retain the 
printed products 2 independent of their thickness during their further 
transport. 
Based upon the showing of FIG. 2 there now will be explained the outfeed or 
delivery of the printed products 2. 
The control roller or roll 29 located in its lower position and shown in 
full lines presses upon the end 24b of the blocking pawl 24 which 
protrudes past the housing 13 and therefore causes a rocking or pivoting 
of the blocking pawl 24 in the direction of the arrow D. During this 
pivotal movement the leg spring 27 is tensioned. Due to this rocking of 
the blocking pawl 27 the blocking mechanism is unlocked, i.e. the end 24a 
of the blocking pawl 24 is raised out of the gap 23. The now relaxing 
spiral spring 17 causes rotation of the hollow shaft 18 together with the 
lever 20 and the roller 21 in the direction of the arrow E (FIGS. 2 and 
5). Consequently, there is simultaneously moved into the open position 
illustrated in FIG. 2 the movable clamping tongue or jaw 6 out of its 
closed position, so that the seized printed product 2 is immediately 
released. Depending upon the magnitude of the tensioning or biasing of the 
spiral spring 17 the movable clamping tongue 6 is lifted way from the 
stationary clamping tongue 7 through a relatively large angle. Since, as 
already previously explained, this spring 17 is tensioned more intensely 
when handling thick products 2 than during the processing of thin 
products, the clamping tongue 6 therefore will lift-off of the clamping 
tongue 7 by a greater amount when processing thick products than thin 
products. Thus, there is realised a faultless opening operation for every 
product thickness. 
Although the spiral spring 17, as already mentioned, exerts a threefold 
function, namely functions as a closing and opening spring for the 
clamping tongue or jaw 6 and as a holder or retention spring for the pawl 
blocking arrangement 22, 23, 24, the printed products are faultlessly 
retained and immediately released, and specifically, independent of their 
thickness. 
By means of the opening device 29, 30 it is possible to open each of the 
gripper clamps 5 or only individual ones of such gripper clamps. As long 
as the control roller 29 is located in the lower end or terminal position, 
as previously described, there is then accomplished an opening of the 
gripper clamps 5. If, however, the control roller 29 is raised into the 
upper position shown in phantom or broken lines in FIG. 2, then the 
control roller 29 does not have any effect upon the blocking pawl 24. 
Consequently, there is not accomplished any opening of the gripper clamps 
5. 
It should be understood that there can be employed instead of the spiral 
spring 17 also a different constructed spring element which connects the 
lever 20 with the clamping tongue 6. 
There has been disclosed as an example of a releasable latching device 
having a defined latching position a pawl blocking arrangement or device 
which can, however, have any other suitable construction from that herein 
disclosed and illustrated. Additionally, there also can be used a 
releasable latching device having another suitable construction. 
While there are shown and described present preferred embodiments of the 
invention, it is to be distinctly understood that the invention is not 
limited thereto, but may be otherwise variously embodied and practiced 
within the scope of the following claims. Accordingly,