Apparatuses according to the invention known in the art as log milling machines are employed for milling joint trenches which are aligned essentially at right angles to the longitudinal axis of a log, said trenches being required chiefly for making timber blocking joints used in log buildings. Conventional types of log milling machines typically include two milling units arranged to move orthogonally with respect to each other. One of the milling units generally is adapted to move in the hori- zontal direction, while the other moves in the vertical direction. Each milling unit generally has two cutter heads adapted to mill the joint trenches simultaneously on two opposite sides of the log being processed. In conventional milling machines, the knife settings of the cutter heads are made by means of spacer blocks, which requires complete dismantling and reassembly of the cutter heads. Hence, the cutter head setting time becomes quite long. During the milling of the log, it is moved step by step. After the trench milling is completed, the machine operator has to move under manual control the log first to the cutting unit and then to the drilling unit.

The movements of the cutter heads occur in a reciprocat- ing manner. This is time-consuming and makes the opera- tion of the milling unit difficult to automate.

It is an object of the present invention to provide an entirely novel type of trench milling machine capable of overcoming the drawbacks of prior-art methods.

The invention is characterized by what is stated in the appende claims.

The apparatus according to the present invention offers a number of significant benefits. For instance, the trenches required in planed logs of log building timber- work and the trimming of the log to a desired length are completed during a single work cycle of the apparatus.

Hence, the processing time per log is shortened in a significant manner. Also the amount of manual work phases has been shortened essentially. A maximally effective function of the apparatus is achieved by adapting a plurality of milling units to a single sliding carriage frame arranged to be movable and rotatable on a rotary frame. Extremely short setting times for different trench widths are attained by providing the milling units with a trench width setting facility. Occupational safety is improved by adapting the milling units to operate pro- tected in the interior of the sliding carriage frame.

In the following, the invention will be examined with reference to the attached drawings in which Figures 1-5 show schematic views of an apparatus according to the invention as seen from the wood object infeed end carrying out the different work phases; Figures 6-10 show schematic top views of the apparatus according to the invention carrying out the different work phases; and Figure 11 shows the sliding carriage frame of an apparatus according to the invention.

The apparatus according to the invention for milling at least one joint trench aligned essentially perpendicular to the longitudinal direction of an elongated wood object 1, particularly for milling on a log the trenches of a timber blocking joint required in the timberwork of a log

building, comprises a framework 2 and at least one milling unit 5,6,7,8 having its cutter head unit arranged to move in an essentially orthogonal direction with regard to the longitudinal direction of the wood object 1 being processed. To the framework 2 is adapted a rotary frame 3, which is designed to operate in a rotata- ble manner in a plane essentially orthogonal to the lon- gitudinal axis of the wood object 1, said rotary frame 3 having thereto adapted in a movable manner a sliding carriage frame 4 with at least one milling unit 5,6,7, 8 connected to said sliding carriage frame. In the em- bodiment shown in the diagrams, the rotary frame 3 is arranged to rotate about a horizontal axis, said hori- zontal axis advantageously being aligned parallel to the longitudinal axis or, alternatively, the tangent of the object 1 being processed. The rotary frame 3 is made into an open cage-like frame, whereby the wood object 1 can be passed via the opening remaining in the interior of the open cage structure of the rotary frame.

To the rotary frame 3 is adapted a support such as a circular turntable on which the load-bearing members 16 of the rotary frame are arranged to run. The load-bearing members 16 can be for instance rollers of which one, for instance, is designed to run on the interior surface of the turntable, while the at least two other rollers are adapted to run on the exterior surface of the turntable.

In this manner, the rotary frame 3 can be rotated sup- ported by the roller members 16. The means for rotating the rotary frame may be any of those conventionally used for the control of a rotary motion, such as different bearing constructions or, e. g., gear ring-gear wheel com- binations. The rotation of the rotary frame is accom- plished by rotating at least one of said roller members or equivalent elements. Alternatively, the rotary frame can be rotated with the help of, e. g., a cylinder-piston assembly combined with said roller elements.

The sliding carriage frame 4 is arranged to be slidably movable on the rotary frame 3 supported, e. g., on guides 15. Thus, the sliding carriage frame 4 can be moved in a reciprocating manner with the help of an actuator mechanism 13,14 along the rotary frame 3. The sliding carriage frame 4 is advantageously formed by two sub- frames with an opening remaining between the subframes.

Said subframes of the sliding carriage frame are spaced apart from each other so as to accommodate thereinbetween the wood object 1 being processed. The sliding carriage frame 4 is provided with milling units 5,6,7,8 ar- ranged to operate from opposite sides of the wood object 1 being processed. In the exemplifying embodiment illus- trated in the drawings, the milling units are shown mounted on the subframes. The sliding carriage frame is further equipped with drive means 9,10 for the milling units 5,6,7,8. The drive means 9,10 may comprise, e. g., a drive motor 10 and power transmission means 9 advantageously such as belts, for instance. The milling depth can be adjusted by moving the subframes, advanta- geously in the vertical direction closer to or away from each other. Furthermore, the sliding carriage frame 4 is advantageously provided with at least one cutting assembly 11,12 for trimming the length of the wood object being processed. Advantageously, the cutting assembly is a circular saw 11,12. Preferably, the number of the circular saws 11,12 is two, placed in the longi- tudinal direction of the wood object being processed to the opposite sides of the milling units 5,6. The circular saws are driven by a drive means, which advanta- geously is the drive means powering the milling units.

The milling units 5,6,7,8 are arranged so that always at least two milling units operate in parallel in the moving direction of the sliding carriage frame 4. As will be later described in detail, this arrangement permits a plurality of trenches to be milled on the wood object 1

being processed during a single movement in each direc- tion. The milling units are preferably placed symmetri- cally to each other.

The milling units 5,6,7,8 are equipped with an adjust- ment mechanism for setting the milling width. Each milling unit 5,6,7,8 has at least two cutter heads 18, 19 adapted to be axially movable on the milling unit shaft 21 so as to cooperate at least partially interleaved with each other. For the purpose of milling width setting, the cutter heads are connected to control links 22,23 actuated by an setting device such as an adjustment screw 24, for instance. The rotation of the adjustment screw moves the nut members to which the control links are attached. Thus, the position of the cutter heads in the milling unit can be varied, whereby also the milling width is changed. In the embodiment shown in Fig. 11, each milling unit comprises three cutter heads 18,19,20, of which the centermost cutter head 20 is a fixed head and the positions of two other cutter heads 18,19 on both sides thereof are settable on the shaft 21 by means of the adjustment mechanism. Addi- tionally, the adjustment mechanism can be complemented with the control of the log cutting saw assembly 11,12.

Thus, it is possible to keep, e. g., the distance of the log cutting point constant from the distal edge of the trench milled to the log irrespective of setting changes in the trench cutting width. In the embodiment of Fig. 11, the support arms of the cutting saw assembly are pivotally connected to the bushing of the movable cutter heads, whereby the adjustment of the cutter heads by means of the control links forces the support arms of the cutting saw assembly to move in a synchronized manner along with the movement of the cutter heads.

The actuator mechanism 13,14 of the sliding carriage frame comprises a cylinder-piston assembly 13,14. The

cylinder-piston assembly is adapted to be rotating along with the rotary frame, advantageously aligned in parallel with the travel direction of the sliding carriage frame.

The piston rod 14 is connected to the sliding carriage frame. The cylinder-piston assembly is driven by a pressurized medium, whereby the piston rod 14 is extended and the sliding carriage frame is moved from the work phase of Fig. 1 to the work phase of Fig. 2. Therefrom, the sliding carriage frame is cyclically moved up to the work phase of Fig. 5. Obviously, any conventional means can be used for actuating the movement of the sliding carriage frame.

The function of the apparatus according to the invention is as follows: In Figs. 1 and 6 is illustrated the initial position in which a cross section of the wood object 1 being pro- cessed is shown. In the diagram, the sliding carriage frame 4 is in its leftmost limit position. The wood object 1 is resting on a platform not shown in the simplified diagram.

In Fig. 7 is illustrated the next work phase in which the sliding carriage frame 4 has been moved to the right from the position of Fig. 1. In this step, the end of the object 1 being processed is cut by the cutting assembly 11,12 of the apparatus, advantageously comprising a circular saw.

In Fig. 8 is shown the work phase following the log cut- ting, whereby the first milling units 5,6 mounted on the sliding carriage frame 4 are used to mill a trench on the top and bottom surfaces of the object 1 being processed.

In Figs. 2 and 9 is shown the next phase, whereby the sliding carriage frame 4 has been moved into a second

position where the object 1 being processed is located between the first milling units 5,6 and the second milling units 7,8 with regard to the moving direction of the sliding carriage frame.

In Fig. 3 is illustrated the rotation step of the rotary frame 3. Herein, the rotary frame is rotated, most ap- propriately about 90°, supported on the roller members 16 mounted on the framework 2. Thereby, also the sliding carriage frame 4, which is adapted to move on guide rails mounted on the rotary frame, is rotated. Thus, the end of the sliding carriage frame 4 located to the right in Fig. 2 is here rotated into the upright position shown in Fig. 4. The milling units have now assumed new positions close to the side surfaces of the object being processed.

The rotary frame 3 rotates approximately about the longi- tudinal axis or, alternatively, the tangent of the wood object 1 being processed. The second milling units 7,8 are located below the object 1 being processed and the first milling units 5,6 are located above the object 1 being processed. Subsequently, the sliding carriage frame 4 is moved to the work phase shown in Fig. 5, whereby the second milling units can mill trenches to the side surfaces of the object being processed.

Next, the object 1 being processed is transferred forward for a desired length and the corresponding trenches are milled to the object in a reverse order.

Finally, the object is trimmed to desired length by the cutting assembly. The above-described sequence can be used, e. g., for milling on a planed log the trenches (that is, the timber blocking joint trenches and corner joint trenches.) required in the blocking joints of a log building.

Furthermore, the apparatus can be complemented with a separate drilling unit (not shown in the diagrams) which suited, along with the milling operation, for drilling the holes possibly required in the object being pro- cessed. Such holes are, e. g., the dowel holes of log buildings.

Moreover, the entire apparatus is advantageously made rotatable about its vertical axis. In the diagrams, the framework 2 is illustrated to be rotatable about a support bearing means 25. The span of framework rotation angle can be 45°, for instance. The rotation of the framework can be arranged to be actuated manually or by means of a rotating actuator such as a cylinder-piston assembly. While the object being processed is kept sta- tionary, the rotation facility of the framework permits milling of trenches different from those particularly aligned at right angles to the longitudinal direction of the wood object. Thus, it becomes possible to mill various joint trenches such as those required in the bay windows of log buildings or the corners of buildings having a hexagonal layout, for instance.

To those versed in the art it is obvious that the inven- tion is not limited by the exemplifying embodiments de- scribed above, but rather, can be varied within the scope and spirit of the appended claims. For instance, the sliding carriage frame may be equipped with a greater number of milling units.