JPH0292601A - Pallet production unit - Google Patents

Abstract

PURPOSE: To improve a productivity of a wooden pallet by nailing a plate material to a beam material from above and below by a nailing machine while fittings installing the plate material and the beam material are passed through a nailing part, then moving the fittings to a removing part, and removing a completed pallet from the fittings. CONSTITUTION: After plate materials 52, 102 and a beam material 68 are manually installed at fittings 24, the fittings 24 are moved to a nailing part having upper and lower nailing machines 130, 132 of a pair opposed to one another, the machines 130, 132 are substantially simultaneously operated to nail the upper and lower materials 52, 102 to the material 68 while passing the nailing part. And, each time specific plate material is passed through the machines 130, 132, all the plate materials are simultaneously nailed to the material 68, and sequentially nailed to the material 68. The fittings 24 are mounted to be continuously moved to the removing part through the nailed part from the installing part, and a completed pallet is removed from the removing part, and the fittings 24 are again returned to the installing part, again installed at next plate materials 52, 102 to the material 68, and the work is sequentially repeated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Prior Art and Problems] Pallets, especially wooden pallets, are used in large numbers for shipping, storing, handling, etc. many types of products. During such operations, pallets are often damaged and generally have a short lifespan, requiring a significant continuous supply of replacement pallets.

Manufacture of such pallets was initially done entirely by hand, often using jigs or the like to position the pallet parts in a predetermined relationship and joining them together by nailing or other methods.

On the other hand, mass production systems for continuously and automatically producing pallets have been provided, but at great expense.

Thus, although the demand for pallets does not decrease, mass production to satisfy this demand requires enormous equipment costs and labor.

[Means to solve the problem]

The present invention provides an apparatus that can manufacture wooden pallets on a relatively high production basis without requiring the large-scale machinery and associated enormous costs conventionally required for mass production of pallets.

The present invention thus provides a manufacturing apparatus that can be constructed at a fraction of the cost of fully automated systems such as those described above, that can be operated with minimal effort, and that can continuously produce substantial quantities of pallets.

As described below, the pallet manufacturing apparatus of the present invention is equipped with a fixture, and a plate material (sla
t) manually loading the stringer;
The fixture then moves to a nailing section with upper and lower nailers in pairs facing each other, where the nailers operate almost simultaneously to shingle the upper and lower planks, respectively, while passing through the nailing section. Drive nails into the top and bottom surfaces of the The number of pairs of nailers is equal to the number of girders on the pallet, and the fixture is provided with as many actuating means as there are planks on the pallet;
When a board passes and the actuating means actuates the switch, the switch activates the nail gun to simultaneously nail that board into all girders each time a particular board passes the nail gun;
In this way, the planks are successively nailed to the girders.

The fixings are mounted so that they move continuously from the loading section through the nailing section to the removal section, where the completed pallet is removed, the fixings are returned to the mounting section, and then the next step is carried out. Boards and girders are mounted and the work is repeated one after another.

As a result, according to the invention, pallets can be manufactured with minimal effort and relatively low cost, while still achieving high production volumes.

〔Example〕

Next, details of the present invention will be explained with reference to drawings showing embodiments.As shown in FIG.
0) has three main parts: a pallet member mounting part, a nailing part, and a completed pallet removal part from the right side of the figure.

Although the main parts are not shown, the vertical members (14) and (16) and the horizontal member (18) are interconnected by suitable horizontal members.
, (20) and (22) are supported by the main frame (12).

In the mounting section, a fixture (24) (FIGS. 4-8) is placed in an initial position to receive and support the pallet member. The fixture (24) has rectangular tubular sight rails (26) and (2B) extending in the longitudinal direction, and a pair of lateral members (30) and (32) arranged at a predetermined interval.

The second sight rails (34) and (36)
) and (32) (pol) (38) and washer (4)
0). Thus Pol l-(3B
) the second sight rails (34) and (36) can be moved inwardly or outwardly within the fixture (24) and moved to a preselected position by tightening the bolts (38) again. can be fixed to.

Furthermore, square tubular additional structural members (42) and (44) are attached to the horizontal members (30) and (32) in the same way as the second sight rails (34) and (36), and are adjustable with bolts (38) and washers ( 40), the tightening is fixed. Components (4
2) and (44) are the channel member (46) and the angle member (4).
8), for example, the upward side indicated by reference numeral (50) forms a first positioning tool set for supporting and positioning the lower plate material (52) of the pallet. The groove member (46) and the angle member (48) are fixed to each component member (42), (44) by a pole (54) and a nut. The shaft portion of the pole l-(54) is each member (42).

(44), the channel member (46) and the angle member (48) can be moved along the respective component members (42) and (44) by loosening the bolts and nuts. , and can be retightened in the desired position.

Additional angle members (,56), (5B) having upwardly facing sides (60), (62) respectively connect component (42).
) and (44) and an additional component parallel to this (64)
installed on. The upward sides (60) and (62), together with the upward sides (65) of the members on both sides extending in the longitudinal direction, form the longitudinally extending beams (65) as shown in FIG.
68) to form a second set of locators for receiving and supporting.

As shown in Figure 9, the second sight rail (36) and (34
) is attached to a guide (70), a rond (72) is slidably supported on the guide (70), a horizontal rod (74) is attached to the end of the rond (72), and a horizontal rod (74) is attached to the end of the rond (72). Each end of the adjustment member (74) has a longitudinal slot (78).
6) is fixed by welding or the like.

(Although only the second sight rail (36) is shown in Figure 9, (34) has the same structure as (36).) Although only one side is shown in the figure, the adjustment member (76) The shaft of the bolt (80) is supported in the vertically long slot (78),
The shaft portion of the lower angle member (80) passes through a mounting boss (82) fixed to the lower side of the lower angle member (84) by welding or the like. The connecting piece (86) is the lower angle member (84)
is connected to the upper angle member (88). The vertical sides of each angle member (84), (8B) are maintained at appropriate intervals to form a horizontal slot (90).

Although only one slot is shown in the figure, the shaft of a bolt (92) is received in the slot (90), and this shaft also passes through the angle member (94). Angle member (94
) is provided with a notch (96) on the upper side (98), and a substantially rectangular boss (1 (15)) is provided on the back side of the bolt (
92) and the through parts of nuts, washers, etc.
This boss (1 (15)) is slidably supported by the thrower (90). Therefore, this angle member (94)
is movable in the longitudinal direction of the fixture, and has a notch (9
6) A third set of positioning tools for the end of the upper plate of the pallet (1 (12)) can be formed between them. The vertical slots (78) allow vertical adjustment of the third set of positioning tools. It is possible to adapt this locator set to pallet top boards of different thicknesses and girders of different heights.

With the slidable rond (72), the third positioning tool set is first moved outwardly to facilitate the mounting of the pallet bottom plate (52) and sparring (68) as shown in FIG. After mounting, the third positioning tool set is moved inward, and the upper plate material (1 (12)) can be mounted as shown in FIG.

As shown in FIGS. 2 and 3, the main frame (12) is provided with a plurality of brackets (104), and a substantially horizontal plate portion (106) of the main frame (12) is provided with mutually parallel support rails extending in the longitudinal direction. (108) and (108) are attached. The rail (108) slidably supports a receiver (110) fixed to the lower surface of the fixture (24).
can be moved along this rail from the mounting part (on the right side of the figure) to the removal part (on the left side of the figure) shown in FIG.

As shown in Fig. 1, a chain drive device (112) is installed to move the chain between chain wheels (116), (11B), and (120), and the chain is driven by a motor (124) through a gear (122). It is driven and its end (114) is secured to a fixture (24) as shown in FIG. The fixture (24) is therefore moved along the support rail (108) via the chino drive (112) by the motor (124).

Furthermore, as shown in Fig. 1, when the fixture (24) moves from the mounting section to the nailing section, the device
A retaining clamp (126) with a piston and cylinder (128) may be provided in slidable contact with (12).

In the nailing section, a set of upper and lower nailers (130)
, (132) are arranged so that the upper and lower ends of the pallet can be nailed to the intermediate girders almost simultaneously.

Nailers (130) and (132) can be commercially available and do not themselves constitute the invention, but as shown in FIG.
34), and female threaded portions (136) are provided at both ends of the horizontal rod (134).
36) is a vertical screw shaft (1) pivotally supported by the vertical member (16).
38), and the lower end of the screw shaft (13 threads) has a chain wheel (1
40) are provided, and left and right chain wheels (140), (14
A chino (142) is installed between 0). A handle (144) is attached to the left screw shaft (13B), and by rotating the handle (144), the screw shafts (138) on both sides rotate synchronously, and the lower nail gun (132) is rotated. This is so that it can be raised and lowered synchronously.

The upper nailer i (130) is mounted on the horizontal rod (146), and screw shafts (148) are loosely fitted into the holes at both ends, and there is no screw connection between them, but there is a female screw member. (150) is prevented from rotating and is screwed into the screw shaft (14B), on which each end of the horizontal rod (146) rests. A chain wheel (152) is provided at the upper end of each screw shaft (148), and a chain wheel (154) is installed between the left and right chain wheels (152), (152), and as shown in FIG. A handle (156) is provided at the upper end of the screw shaft (14B), and by rotating this handle (156), the female screw members (150) on both sides move up and down synchronously, and the upper nail gun (130) is moved up and down. Move it up and down.

Further, a bracket (158) is fixed to the horizontal rod (146), and a wheel (160) is attached to this. The wheels (160) engage with the upper plate (1 (12)) while the plate of the pallet is moving through the nailing section, and the wheels (160) engage the upper plate (1 (12)) to move the nailer correctly.
(12) Serves as a position above. Thus, the nail gun is first positioned at approximately the correct height relative to the height of the pallet being moved, and when there is a variation from this height, this wheel (
160) is corrected by securing it to the upper plate material (1 (12). This is because the end of the horizontal rod (146) is attached to the screw shaft (
Since it is loosely fitted into the female thread member (150)
This is because it can rise regardless of the change in thickness of the pallet member.

Further, as shown in FIG. 2, upper and lower detection switches (162) and (164) are attached to the nailing section to detect the presence or absence of upper and lower plates at predetermined positions during pallet movement. If the board is not in position to be nailed into the girder, switches (162) and (164) will not activate the nailer circuitry as described below.

Referring to FIGS. 2, 3, 10 and 11, a longitudinally extending upwardly facing plate (166) is mounted on the sight rail (28) of the fixture; A plurality of relatively narrow strip plates (16B) and a slightly wide but thin strip plate (170) are sequentially attached to the outer surface of the plate with bolts (172), etc., thereby forming a T-slot (174). The head of the bolt (176) is supported on this, and the bolt (176) extends through the boss (178), and a nut (180) is screwed onto the outer end of the bolt (176). . The boss (17B) has a right cylindrical portion (182), and the small diameter portion is supported by the narrow portion of the T thrower (174). Therefore, the bosses (178) are arranged along the sight rails (28) and are actually arranged in correspondence with the positions of the upper and lower plates of the pallet fed by the fixtures (24).

The main frame (12) has upper and lower approach switches (184),
(186) is attached. This switch is of a normal type, and when the actuating boss (17B) passes, it goes through an appropriate control circuit and starts each nailing machine at the moment the upper and lower plates move under or above the nailing machine, respectively. Operate. This control circuit is of conventional type and does not itself constitute an invention. However, even if the proximity switch sends a signal to the control circuit, the detection switch (162) or (1
64) does not detect that the board is in the correct position, the circuit does not work for that board and the nail gun does not operate.

Following nailing of the pallet members, the fixture carrying the completed pallet is moved to the removal station shown on the left side of FIG. As shown in Figure 3, there is a cylinder and a piston (19
A removal tool (188) that moves vertically by the removal tool (18B) and moves inwardly under the control of a horizontally operating piston and cylinder (194) that is mounted inwardly on the removal tool (18B) and moves inwardly to remove the finished pallet. Pick-up arms (192) are arranged to engage the front and rear upper plates. (Figure 1).

A cam operating piece (196) is also fixed downwardly to the removal tool (188) as shown in FIGS. 1 and 3.

The outer surface (198) of the lower end of the cam actuating piece (196) is inclined upwardly, so that when the removal tool (188) is lowered to the removal position, the upper angle member (8B) The third positioning tool set that engages with the pallet top plate (1 (12)) and supports the pallet top plate (1 (12)) is moved outward and removed from the pallet.
The picking arm (188) moves inward as the lifting arm (188) rises.
92) picks up the pallet.

When the fixture (24) is thus moved to the removal section, the removal tool (18B) is lowered and the cam actuating piece (196) moves the third set of locating tools outwardly, causing the pick-up arm (1
92) inward to engage the lower surface of the pallet top plate. Therefore, when the removal tool is raised, the completed pallet is removed from the fixtures, so the fixtures are returned to the mounting section, the other lower plates and girders are mounted again, and the third positioning tool set is manually installed. After moving inward, the upper plate material is supported.

As shown in Fig. 1, limit switches (2 (15)) and (2 (12)) are arranged at both ends of the main frame (12) to stop the movement of the fixture along the support rail (108). The switch (2 (
12) also serves to operate the motor (124) to return the fixture to the mounting section after a suitable time for removal of the completed pallet.

With the above structure, when the fixing device (24) is placed in the mounting section, the lower plate material (52) of the pallet is placed on the fixing device (24) using the first positioning device set formed by the upward side (50). ), and then the girder (68) is mounted on the upward side (
60), (62) and (64). Finally, the third set of positioners formed by the notch (96) is the seventh
The top plate of the pallet (
1 (12) is mounted on the fixture (24). All of these are done manually. Next, by starting the motor (124) via an appropriate control circuit, the chain drive device (112)
The fixture (24) is moved along the support rail (108) to the nailing section where the upper and lower nailers (130),
(132) simultaneously nails the upper and lower surfaces of all the girders on the top and bottom of the pallet each time each plate passes through the nail gun. The operation of the nail gun is controlled by the operation boss (17
8) is performed by passing through the approach switches (184) and (186), but as mentioned above, the detection switch (
When step 162) or (164) does not detect that the plate of the pallet is at the nailing position, the plate is not nailed.

The motor (124) drives the fixture (24) continuously without interruption on the support rail (108) until it reaches the end limit switch (2 (12)) and stops, where the removal fixture The lowering of the remover moves the third set of locators outward, and then the pick-up arms move inward to engage the top plate of the completed pallet.The remover then moves up. to remove the pallet from the fixture.The fixture returns to the loading section, the unloader lowers again, the pick arm moves outward to release the pallet onto the platform in the unloader, and then the unloader returns to its original position. and waits until the next pallet is delivered by the fixture.

When the fixture brings the next pallet from the mounting section through the nailing section to the removal section, the fixture transports the previous completed pallet placed on the table in the removal section from the removal section to the rails (not shown) or other pallets. onto a conveyor, where the finished pallets are collected for shipment.

Furthermore, the control circuit can be set to automatically perform the above cycle when the fixture is returned from the removal station, after stopping for a sufficient time to reload the loading station with material. The device can also be set up by the operator to operate on a cycle-by-cycle basis, ensuring that the fixture is properly loaded with material. It is also possible to extend the upward side (50) of the first positioning tool set upwards by an appropriate height to support the upper plate (1 (12)), so that it can also be used as the third positioning tool set. It is.

As is clear from the above description, the present invention provides an apparatus that can mass-produce pallets without requiring expensive equipment or much labor.

The configurations of the devices described in Section H are examples of the present invention, and the present invention is not limited to the detailed configurations of these devices, and changes can be made within the scope of the invention.

[Brief explanation of drawings]

The drawings show an embodiment of the device of the present invention, FIG. 1 is a front view, the following is an enlarged view, FIG. 2 is a sectional view taken along the line 2-2 in FIG. 1, and FIG. 4 is a partially cutaway plan view of the fixing device, FIG. 5 is a plan view of the fixing device showing the state in which the pallet bottom plate is mounted on the pallet bottom plate, and FIG. 6 is a partially cutaway plan view of the fixture. FIG. 7 is a plan view of the fixture showing the state in which girder materials are mounted on the positioning device; FIG.
The figure is a plan view of the fixing device showing the state in which the plate material is mounted on the pallet.
FIG. 9 is an exploded perspective view of the positioning device for pallet upper plate materials;
Figure 1O is a view taken along the line 10-10 in Figure 11.
FIG. 1 is a partially cutaway side view of the main frame and fixture showing the relative positions of the actuation boss and the approach switch. (10)...Pallet manufacturing equipment, (12)...Main frame, (24)...Fixing tool, (52)...Pallet lower plate material, (68)...Pallet girder material, (1 (
12)...Pallet top plate material, (108)...Support rail, (112)...Chain drive device, (12)...
4)...motor, (126)...holding clamp, (130), (132)...nail gun,
(162), (164)...detection switch, (
178)...Operating boss, (184), (186)
...Proximity switch, (188) ...Removal tool, (1
92)...Lifting arm, (196)...Cam operating piece, (2(15)), (2(12)...Limit switch.

Claims (15)

[Claims] (1) A pallet manufacturing device having longitudinally extending girders and upper and lower plates respectively attached to the upper and lower surfaces of the girder, which are arranged at a main frame and at the upper end of the main frame. a mounting portion of the main frame, a nailing portion provided below the mounting portion of the main frame, a removal portion provided below the nailing portion of the main frame; a fixture movable to the removal section; a means for stopping the fixture on the mounting section; and a means for stopping the fixture on the mounting section; The melted wood is placed in a position approximately similar to that of the completed pallet by extending the plate material transversely to the direction of movement of the fixture along the main frame and extending the girder material approximately parallel to the direction of movement. means for supporting the fixing tool from the mounting section through the nailing section to the removing section; Accordingly, the pallet manufacturing apparatus is equipped with a plurality of nailing machines for sequentially nailing each of the upper and lower planks to the girders. (2) The fixture is provided with a set of first, second, and third positioning tools that respectively support the lower plate material, the girder material, and the upper plate material, and the position of each positioning tool is determined by other positioning tools. Claims further comprising means for adjusting relative to the fixtures and means for moving said third set of locating fixtures outwardly to facilitate mounting of said bottom plate and spar to the fixture. The pallet manufacturing device according to item (1). (3) The pallet manufacturing apparatus according to claim 2, further comprising means combined with the removal section to move the third positioning tool set outwardly by a cam action. (4) The nailing machine is composed of a plurality of sets of nailing machines arranged in upper and lower pairs to face each other, and when the above-mentioned fixing tool passes through the nailing part when combined with the above-mentioned upper nailing machine, The pallet manufacturing method according to claim 1, further comprising means for engaging the upper plate material supported by the fixture and adjusting the vertical position of the upper nailer in accordance with the height of the upper plate material. Device. (5) The means combined with the upper nail gun comprises a plurality of wheels connected to the nail gun so as to move up and down together with the nail gun and to engage with the upper surface of the upper plate material. The pallet manufacturing device according to claim (4). (6) Further, a number of actuating bosses provided on the fixing device corresponding to the number of upper and lower plate members supported and supported by the fixing device, and a number of actuating bosses provided on the main frame along the path of the actuating boss, and the fixing device Claim (1) The nail gun is provided with upper and lower approach switches activated by the actuation boss when moving along the main frame, and a control means for actuating the nail gun in response to the approach switch actuated by the actuation boss. Pallet manufacturing equipment described in . (7) Furthermore, the fixing device is placed above and below the nailing section, and when the above-mentioned fixing device moves to the nailing section, it outputs the presence or absence of a board, and correspondingly stops the operation of the nailing machine when there is no board. The pallet manufacturing apparatus according to claim 6, further comprising a detection switch configured to do so. (8) Claim further comprising: a removal tool provided in the removal section so as to be movable up and down, and a picking arm provided on the removal tool so as to be movable in the horizontal direction, and capable of engaging and disengaging from the completed pallet at the removal section. The pallet manufacturing device described in 1). (9) Furthermore, a restraining clamp is attached to the main frame, and the operating surface of the clamp is slidably engaged with the upper surface of the upper plate supported by the fixture when the fixture moves to the nailing part. The pallet manufacturing apparatus according to claim (1). (10) The pallet manufacturing apparatus according to claim (1), further comprising means for adjusting the movement of the nail gun in the vertical direction. (11) The number of nailers is the same as the number of girders supported by the fixture, and the spacing is the same as the spacing between the girders.
The pallet manufacturing device described in 1). (12) A plurality of wooden girders spaced apart laterally and extending in the longitudinal direction; A pallet manufacturing device comprising plate materials and a plurality of nails that interconnect the girder materials and the plate materials, the apparatus comprising: a main frame; a mounting section disposed at the upper end of the main frame; and the mounting section. a nailing part disposed below the nailing part; a removal part disposed below the nailing part; a fixture movable along the main frame from the mounting part to the nailing part; and a means for mounting the upper and lower plates and the girder on the fixing device between them, the fixing device receiving and supporting the ends of the lower plate and fixing them at predetermined intervals. a first positioning tool set for arranging the equipment in a direction transverse to the direction in which it travels; and a second positioning tool set for receiving and supporting the girders and stacking them on the lower plate material at a predetermined interval at approximately right angles. set, a third positioning tool set for supporting the ends of the upper board material and overlapping the lower board material and the girder material at predetermined intervals at approximately right angles to the girder material; means for mutually adjusting; and said first
and means for moving the third set of positioning tools outwardly to facilitate mounting on the second set of positioning tools; means for continuously moving in one direction from the frame section through the nailing section to the removal section; a plurality of nailing machines provided in the nailing section and facing each other vertically; means for adjusting the movement of the upper nailer; coupled to the upper nailer so as to move up and down with the nailer, and engaging the upper surface of the upper plate to place the upper nailer in a predetermined relationship with the upper surface of the upper plate; a plurality of wheels positioned at;
A pallet manufacturing apparatus comprising control means for operating the nailing machine when the fixture passes through the nailing section. (13) The control means includes an actuation boss disposed longitudinally on the fixture, and a proximity switch disposed on the main frame along the path of the actuation boss when the fixture moves along the main frame. The pallet manufacturing apparatus according to claim 12, comprising: a pallet manufacturing apparatus according to claim 12; (14) Furthermore, it is attached to the above-mentioned removal part so as to be movable up and down,
13. The pallet manufacturing apparatus according to claim 12, further comprising a removing tool having a pick-up arm that moves horizontally to engage and disengage the completed pallet. (15) Vertically long wooden girders placed at intervals in the horizontal direction, upper and lower horizontally long planks arranged at intervals in the longitudinal direction and overlapped on the upper and lower surfaces of the girders, and the girders and a main frame; a first positioning tool set for supporting the lower planks and arranging them at a predetermined distance from each other; a second positioning tool set for supporting the ends of the upper plate material and stacking it on the lower plate material at a predetermined interval from each other at a right angle to the lower plate material; a third positioning tool set for stacking the girder material and the lower plate material at right angles to each other at a predetermined interval; a means for mutually adjusting the positions of the positioning tools; means for moving the third positioning tool set outward to facilitate mounting on the positioning tool set; upper and lower nails provided in the middle of the main frame and facing each other; a nailing section having the same number of pairs of nailers as the girders and at the same intervals as the spacing when the girders are mounted on the second positioning tool set; the upper nailer being integrated; means for vertically adjusting; means for integrally vertically adjusting the lower nailer; provided in the main frame in the longitudinal direction, the fixture being movable in the longitudinal direction between the nailers facing upwardly and downwardly; a rail that is supported on the main frame and extends to the top and bottom of the nailing part and has an interval corresponding to the width of the fixing device; a chain drive device for moving the fixing device from the upper mounting section to the lower removal section of the nailer; provided on the main frame, and engaged with the upper surface of the upper plate material in the operating position when the fixing device moves to the nailer; a clamp up and down mechanism for lowering the restraining clamp to the operating position and raising it from the operating position; a clamp vertical mechanism coupled to the upper nailer and moving up and down together with the upper nailer; a plurality of wheels that engage with the upper surface to position the upper nailer in a predetermined relationship with the upper surface of the upper plate; a number corresponding to the number of upper and lower plates supported by the fixture; an actuation boss disposed longitudinally on the fixture; and an actuation boss disposed on the main frame along the passage of the actuation boss so that the fixture is actuated by the actuation boss when the fixture moves along the rail. an upper and lower approach switch; a control means for activating the nail gun in response to actuation of the approach switch by the activation boss; and a control means disposed over the nailer when the fixture is moved into the nailer. A board material detection switch facing upward and downward, which detects the presence or absence of board material and prevents the nailer from operating when no board material is present; A removal tool provided below the nailing part so as to be movable up and down; and the removal tool. a pick-up arm provided on the removal tool and capable of moving in the longitudinal direction to engage and disengage the completed pallet; provided on the removal tool and moving up and down together, and engaging with the third set of positioning tools to move it outward; cam means capable of moving;
and a pallet manufacturing apparatus comprising limit switches configured to stop the movement of the fixture along the rail at upper and lower positions of the nailing part.