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Publication numberUS3733017 A
Publication typeGrant
Publication dateMay 15, 1973
Filing dateMar 22, 1971
Priority dateMar 22, 1971
Also published asCA967530A1
Publication numberUS 3733017 A, US 3733017A, US-A-3733017, US3733017 A, US3733017A
InventorsPletz M
Original AssigneeK2 Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Adjustable pack frame
US 3733017 A
A pack frame for hikes which is light and flexes with movement of the wearer's body. The majority of the carried weight is supported by the hips and the pack is adjustably suspended within the frame such that it may be placed in the most comfortable position relative to the frame. Shoulder straps are provided to keep the pack from pivoting about the weight supporting belt but carry very little strain themselves. The shoulder straps themselves are adjustable as to length and pivotable about the anchor points thus making the pack extremely versatile and comfortable for wearers of varying stature.
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Description  (OCR text may contain errors)

United States Patent 1191 Pletz [451 May 15,1973

I54] ADJUS TABLE PACK FRAME [75] Inventor: Murray J. Pletz, Bellevue, Wash.

'[73] Assignee: K2 Corporation, Vashon, Wash.

[22] Filed: v Mar. 22, 1971 [2]] Appl. No.: 126,408

FOREIGN PATENTS OR APPLICATIONS 813,280 2/1937 France ..224/8 R Primary Examiner-Gerald M. Forlenza Assistant Examiner-lerold M. Forsberg Attorney-John O. Graylarid, Delbert J. Barnard, James R. Uhlir and Robert B. Hughes 57 ABSTRACT A pack frame for hikes which is light and flexes with movement of the wearers body. The majority of the carried weight is supported by the hips and the pack is adjustably suspended within the frame such that it may be placed in the most comfortable position relative to the frame. Shoulder straps are provided to keep the pack from pivoting about the weight supporting belt but carry very little strain themselves. The shoulder straps themselves are adjustable as to length and pivotable about the anchor points thus making the pack extremely versatile and comfortable for wearers of varying stature.



SHEET 3 BF 3 FIG 6 INVENTOR MURRAY J. PLETZ BY ATTORNEYS ADJUSTABLE PACK FRAME BACKGROUND OF THE INVENTION The present invention relates to apparatus for transporting loads on a mans back. Specifically the present invention relates to an improved pack frame which effects optimum distribution of a load to the human body, utilizing a simplified versatile structure.

It is commonly understood that a load is most easily endured by the human body ifit is positioned above the shoulders and close in to the neck. Placement of the load in this manner directs the weight through the shoulders and torso to the hips enabling the strongest body muscles to bear the major bulk of the burden. Prior art pack frames seeking to effect the foregoing load placement have employed complicated frame structures and elaborate shoulder harnesses.

Accordingly it is an object of the present invention to construct a pack frame of simple and economical structure and assembly capable of optimumly distributing the weight of the load to the hip portion of the body without the necessity of passing through the upper torso. To accomplish this objective the present invention employes a generally L-shaped frame having shoulder straps for retaining the load close to the body of the wearer. A waist belt is coupled to the frame near the foot of the frame to secure the lower end of the pack frame to the body and to absorb a major portion of the load.

It is another object of the present invention to construct a pack frame which can be readily altered in size to accommodate different types of loads and for use in different environments.

It is also an object to construct a pack frame so that it may be completely disassembled and repaired or modified. This object is accomplished by constructing the pack frame from interlocking parts held in place by the tension forces developed in the shoulder straps and other straps holding comfort pads against the back of the bearer.

Accordingly another object of the invention is to design a pack frame having a flexible frame structure capable of absorbing shock when dropped to the ground or the like when fully loaded.

Yet another object of the present invention is to provide a pack frame which is adjustable thus making it possible to shift the weight carrying portions with relationship to the rest of the frame enabling placement of the weight at different portions on the body or on different portions within the frame for persons having different statures.

As will hereinafter be more specifically described this combination of features results in a pack frame which is extremely versatile and adjustable in that it will fit a variety of human shapes as well as allow an infinite amount of variation as to the placement of the load within the frame itself.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a pictorial representation of the pack frame including the pack itself located upon the inventive frame structure.

FIG. 2 is an exploded view of the frame structure showing the various parts in greater detail.

FIG. 3 is an enlarged portion of the connection between the shoulder straps and the frame structure.

FIG. 4 is a pictorial representation of the means by which the pack sack is suspended from the frame.

FIG. 5 is a sectional view looking downwardly on the frame more particularly illustrating the means for holding the frame side rails in position.

FIG. 6 is an enlarged portion showing one of the side pockets having a double zipper combination hereinafter described.

DETAILED DESCRIPTION OF THE DRAWINGS The pack frame is preferably fabricated from aluminum bar stock and has a pair of side bars 21-21 connected at the top by an inverted U-shaped top bar 22 and at the bottom by a rearwardly arched shelf bar 23. At its end the top bar 22 is formed with necked portions 22a to fit into the upper ends of the side bars and is retained by pins 24 passing through mating holes in the side bars and necks 22a. Detachable keeper rings 25 pass through terminal holes in the pins 24. The shelf bar 23 can be made integral with the side bars as illustrated or can be a separate member which is necked to interfit with the lower ends of the side bars in the same manner as the connection of the top bar 22.

The pack frame is further cross-braced by stationary cross-bars 26-27 and an adjustable cross-bar 28 located on upper straight sections 21a of the side bars which extend about half of the length of the side bars. At the lower ends of these straight sections the side bars 21 bend forwardly at the approximate location of the cross-bar 26 providing a rearwardly sloped center section 2111 and then bend forwardly at the approximate location of the cross-bar 27 providing a bottom section 21c which forms an obtuse angle with the center section 21b which is slightly greater than the obtuse, angle at the juncture of the upper and intermediate sections 21a-21b. A pair of two adjustable socket blocks 29 and two pairs of stationary socket blocks 30 are sleeved on the side bars 21, the blocks 30 being'staked at 31 to hold them in position. Each of the blocks 30 has a vertical through bore 30a for receiving the side bars and a horizontal cross-bore 30b extending from its inner side face to the vertical bore to serve as a retaining socket for a respective end of one of the cross-bars 26-27. Similarly, the adjustable blocks 29 have a vertical through-bore 29a and a horizontal socket bore 29b for holding the ends of the cross-bar 28. In addition, the block 29 has a second horizontal bore 290 which is threaded to receive a set screw 32 for engaging the respective side bar 21. In this manner the blocks 29 with the cross-bar 28 are locked relative to the pack frame in selected vertical position.

It will be noted that the three intermediate cross-bars of the frame are arched rearwardly in progressively greater amounts starting with the adjustable bar 28 and continuing downwardly with the stationary bars 26 and 27 so as to allow for lateral curvature of the packers back. The end portions of the cross-bars are straight to fit into the sockets of the blocks 29-30, and are held in sockets by the top and bottom bars 22-23 and by a pair of back pad assemblies 33-34 to be later described.

In the production of the pack frame components the four sockets blocks 30 are sleeved onto the length of tubular bar stock for forming the side bars 21 and shelf bar 23, and are staked into proper position before the bends in the side bar are formed. The adjustable blocks 29 are then sleeved into the straight portions 21a and the side bars are sprung apart sufficiently to insert the ends of the cross-bars 26-27 into the sockets 30b and the cross-bar 28 into the sockets 29b. Following this the top bar 22 is fitted by its necked ends 220, the upper ends of the side bars 21 and the locking pins 24 and keepers are applied.

Attention is now directed to a pair of shoulderstrap assemblies 40 each of which comprise an intermediate shoulder pad 41 and front and back strap extensions 42-43 from the pad which include respective buckles 42a-43a for adjusting their effective length. The lower strap components of the strap units 42-43 have respective terminal grommets 44-45 which are sleeved on opposite end portions of a respective pin 46 passing laterally through the lower end portion of the corresponding side bar 21 and having a detachable keeper ring 47. At its upper end each shoulder pad has a tab extension 48 with a grommet 50 cooperating with a grommet 51 provided at the top of the upper strap component of the front strap assembly 43. The two sets of these grommets 50-51 are sleeved on a pair of pins 52 depending from the adjustable cross-bar 28 in respective positions equally spaced from the side bars 21. Two or more sets of vertical holes 53 for the pins 52 are provided in the cross-bar 28 so that the lateral spacing of the shoulder pads 41 can be adjusted. The pins 52 are held at the top by keeper rings 54 and are free to swivel in the holes 53 so that the shoulder pads are free to turn at the top relative to the pack frame to adjust to the hikers shoulder contour.

It is of importance to note that the pins 52 (see FIG. 3) are purposely long enough to give play between the grommets 50-51 and the underside of the adjustable cross-bar 28, and that the grommets 50 are underneath the grommets 51. This arrangement causes the front and back strap units 42-43, when properly adjusted as to effective length, to be equally tensioned by the weight of the pack bearing down on the shoulder strap assemblies at the location of the lower pins 46 and prevents vertical load from being transmitted from the cross-bar 28 to the shoulder pads 41. To elaborate, again referring to FIG. 3 when the front strap units 42 are tensioned respective to pack load bearing down on the lower grommets 44 through the pins 46, the upper grommets 50 tend to walk slightly down the pins 52. As they do so, the grommets 50 engage the underside of the grommets 51 and cause them to move in concert and equally tension the rear strap units 43. The pins 52 are long enough so that when the strap units 42-42 are properly adjusted by use of the buckles 42a-43a, the grommets 51 remain spaced below the adjustable cross-bar 28. As a result, normally none of the weight of the pack is carried from the cross-bar 28 downwardly against the rear end of the shoulder pad 41. Instead, the vertical load on the tab extension 48 of the shoulder pad is obtained from tension on the rear strap unit 43. In that respect it isjust as if the tab 48 were integral withthe upper component of the strap assembly 43. The described arrangement has the added advantage that the shoulder pads 41 are free to turn relative to the pack frame as before mentioned.

The principal functions of the pins 52 in addition to permitting the aforesaid turning of the shoulder pads, is to hold the upper portion of the pack frame in against the back of the hiker and to prevent the pack frame from shifting laterally or twisting relative to the hiker.

The vertical adjustability of the blocks 29 which hold the cross-bar 28 is advantageous in obtaining maximum comfort and fit for the particular hiker using the pack. Ideally, the lower pins 46 should be located at the smallest part of the waist and the adjustable cross-bar 28 should be at the shoulder level. This can be readily accomplished by freeing the upper pins 52 from the cross-bar 28 but leaving them in the grommets 50-51, adjusting the effective lengths of the shoulder straps by use of the buckles 42a43a until the pack frame is at the proper level, raising or lowering the bar 28 until it is at the level of the upper portion of the pins 52, and then inserting the pins through the proper set of the holes 53 determined by the neck size of the hiker and applying the keepers 54.

The back pad units 33-34 (See FIG. 5) each comprise an elongated pad 60 extending the width of the pack frame and strap extensions 61-62 with a buckle 63 for tensioning the pad. These straps pass around the side bars 21 and are cinched at the back of the frame. The pad units are vertically adjustable relative to the pack frame to fit the hikers comfort, and normally are positioned approximately in the positions illustrated in the drawings. The pad components 60 may comprise fabric envelopes filled with plastic foam or other suitable padding material, but it is intended that the word pad shall also include open-mesh, elastic and other suitable relatively thin unfilled materials which will readily contour to the hikers back.

it is preferred that the pack be equipped with a waistband assembly which will transfer much of the load of the pack to the hikers hips. This unit may be connected to the pack frame by grommets 71 which are also sleeved into the outer ends of the pins 46 which hold the lower ends of the shoulder strap assemblies 40. These grommets 71 are located in strap extensions 73 of a back pad 72. The material of these extensions continued from the ends of the back pad 72 to form extension loops 74 which retain buckles 75 for receiving rear belt extensions 76 of a pair of hip pads 77 which have front belt extensions 78. One of the latter is connected to a suitable belt buckle 79. In effect, the back pad 72, extension loops 74, buckles 75, rear belt extensions 76, hip pads 77, and front belt extensions 78 comprise a continuous waistband having adjustable hip pad locations and arranged to be cinched at the front. When properly adjusted this waistband carrier a major part of the weight of the pack by the extensions 73 which connect to the lower end portion of the pack frame by the pins 46 and grommets 71. The rest of the weight is carried by the shoulder strap assemblies 40 by downward pull exerted by the pack on the front and back shoulder strap units 42-43 via the pins 46 and grommets 44-45.

As another part of the present invention an adjustable U-shaped supporting bar 80 is provided which is mounted on the side bars 21 by a pair of slide blocks 29' which are of the same construction as the adjustable socket blocks 29, except that they are also formed with a horizontal pin opening 81 which crosses the socket bore 29b for receiving a locking pin 82 having a keeper 83. The blocks 29' are turned a relative to the blocks 29 so as to face the socket bores 29b toward the rear for receiving the ends of the bar 80. These ends are laterally bored to mate with the holes 81 and receive the locking pins 82.

The pack sack 80 (See FIG. 4) for use with the described packboard is provided at the top with a sleeve 91 open at its end to the back of the pack sack and extending from these open ends along the lateral sides of the pack sack and along the front side thereof. The width of the sleeve 91 is sufficient to permit the U- shaped bar 80 to be threaded therethrough when it is detached from the pack frame and then the bar 80 and pack sack as a unit are secured to the pack frame by inserting the ends of the bar into the sockets 29b of the slide blocks 29' and inserting the locking pins 82 and related keepers 83.

Near its lower rear corners (See FIG. 1) the pack sack 90 is provided with a pair of straps 92 having buckles 93. These straps are arranged to be passed and secured around the side rails 21 to hold the lower part of the pack sack against the pack frame and are slidable along the side rails to conform with vertical adjustment of the blocks 29' to achieve the desired height of the pack sack relative to the pack frame to suit the hiker.

Reference again being had to FIG. 4, the upper wall 94 of the pack sack 90 is recessed and surrounded on three sides by the sleeve 91 and at the back by the flap 95 which is an upward continuation of the back wall 96 of the pack sack. This flap is made wider than the back wall 96 and substantially longer than the front-to-back width of the upper wall 94 so that a jacket or other objects can be conveniently stored in the tray created by the upper wall 94 as the tray bottom and the sleeve 91 and lower back portion of the flap 95 as the four side walls of the tray. The flap 95 is provided with tie strings 97 at its front corners which can be secured to anchor loops 98 provided on the sides of the pack sack after the flap has been pulled over the top of the tray to protect the stored object from the weather and hold it in storage position. The rear corners of the flap are preferably sewn to the back edges of the pack sack as at 99 below the mouths of the sleeve 91 so that the pull lines of the tie strings 97 will be such as to keep the longitudinal side edge portions of the flap over the lateral sides of the tray.

The rest of the compartition of the pack sack can be selected to fit particular needs. Commonly, there will be two major pockets open to the front of the pack sack and several side pockets, all with zipper closures. The lower end of the pack sack is spaced above the lower shelf bar 23 providing storage space which is commonly used for a sleeping bag.

It is to be noted that for convenience of the user the pockets may well have double acting zippers such that they may easily be opened from either end, in the middle or anywhere in between without disturbing the contents. This convenience is available by providing a zipper for the entire opening having a chain of teeth extend along each edge and a pair of oppositely facing sliders mounted thereon such that when the sliders are adjacent each other the opening is closed. Referring to FIG. 4 it can be seen that the two sliders 100 completely close the chains of teeth 102 thus closing one of 6 the main pockets. FIG. 6 illustrates the application of the opposed sliders 104 to a side pocket 106. It is to be noted that the pocket further includes a flap 108 to make the compartment weather tight.

The embodiments of the invention in which a particular product or privilege is claimed are defined as follows:

1. A flexible pack frame for hikers, comprising;

a pair of relatively rigid side members,

a transverse bottom member inter-connecting the side members,

a transverse top member connecting the side membars,

at least one transverse intermediate member, adjustable along the side members, and capable of being locked at an infinite number of positions along the side members,

an adjustable belt attached adjacent the bottom portion of the side members and adapted to encircle and be tightened about the waist portion of the wearer and bear the weight of the pack,

a pair of non-weight bearing shoulder straps having a first end attached to the belt and having a second end attached to the bottom portion of the adjustable transverse member said straps adapted to pass over the shoulders of the wearer and prevent movement of the pack outwardly from the wearers body, the connection between'the second end and the transverse member permitting the distance be tween the straps to vary and permitting relatively free pivotal movement of said straps,

said shoulder straps including pads to cushion the wearers shoulders and means whereby the length of the straps may be adjusted fitting the pack to the individual while keeping the pads centered upon the shoulder.

2. A frame as in claim 1 and further including a shelf extending rearwardly from the top portion adapted to have a pack suspended therefrom thereby placing the effective weight moment high on the frame and thus high upon the wearer.

3. A frame as in claim 2 wherein the shelf is adjustable along the length ofthe side members thus enabling the placement of the weight at a position of greatest comfort for the wearer.

4. A pack frame as in claim 2 and further including a pack bag suspended from the shelf and having a covered storage area above the shelf.

5. A pack frame as in claim 2 and further including a pack bag suspended from the shelf and having pockets closed by a pair of opposed zippers allowing access to the pack from any portion of the opening without disturbing the rest of the contents or exposing them to the elements.


paten N 3 ,733 ,017 Dated May 15 1973 MURRAY J. PLETZ I ventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column *4 line +5 change "carrier" to --w carries Column line 22 cahce l "non-weight bearing" Column 6 line 25 after "straps" insert being Column 6 line 36 change to Column 6 after insert the following:

such arrangement and .adjustabili'ty of said V belt and said shoulder straps permitting selectively variable distribution of the weight of the pack betwee n the hips and-shoulders of the wearer as desire d.

' Signed-and sealed this 27th day of November 1973.

(SEAL) Attest: V

EijWARD p mamm I o, Arresting Officer i V Acting Commissioner of Patents

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Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3889859 *Jun 14, 1973Jun 17, 1975Samsonite CorpPack frame and sack therefor
US3938718 *Apr 11, 1974Feb 17, 1976The Coleman Company, Inc.Backpack frame and assembly
US3968910 *Jul 11, 1974Jul 13, 1976Gerber Products CompanyShoulder pack child carrier
US4013201 *Jan 26, 1976Mar 22, 1977Glenn James PotterFatigue reducing backpack harness
US4087031 *Oct 6, 1975May 2, 1978Fenner Peter MBackpacking frame
US4214685 *Jul 27, 1977Jul 29, 1980K-2 CorporationBackpack load carrying system for hikers
US4303186 *Aug 11, 1980Dec 1, 1981Ollinger Iv Charles GTriaxially pivotable backpack carrier
US4489866 *Nov 16, 1983Dec 25, 1984Diamond Brand Canvas Products Co., Inc.For hikers
US5004134 *Feb 6, 1990Apr 2, 1991Barry Thomas PBackpack system for beach related activities
US5265780 *Jun 5, 1992Nov 30, 1993Matthews Timothy ICombined backpack frame and climbing stand
US5320262 *Nov 3, 1992Jun 14, 1994Mountain Equipment, Inc.Internal frame pack and support device therefor
US5465887 *Aug 26, 1993Nov 14, 1995Hudson; KeithArchery bow backpack carrier
US5547246 *May 30, 1995Aug 20, 1996Lambert; MichaelCombined canoe carrier and chair
US5564612 *Jan 27, 1995Oct 15, 1996Bianchi InternationalModular backpack
US6015076 *Jun 20, 1997Jan 18, 2000Pennington; DarylBridging hipbelt for a backpack
US6095599 *Jun 14, 1996Aug 1, 2000Lambert; MichaelCombined canoe carrier and chair
US6161739 *Jul 15, 1999Dec 19, 2000Bentzen; MichaelVersatile backpack
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US6651853Apr 16, 2001Nov 25, 2003Richard HigginsBackpack frame, suspension, seat and cot
US7988024 *Feb 12, 2003Aug 2, 2011Beachpacker, LlcBeach equipment carrying apparatus
US8381876 *Aug 1, 2008Feb 26, 2013Rick R. DardenTree climbing tree stand
DE3104855A1 *Feb 7, 1981Jun 16, 1982Jeva Laedervarer ApsRucksack or pack frame
U.S. Classification224/634, 224/635, 224/636, 224/235
International ClassificationA45F3/08, A45F3/04
Cooperative ClassificationA45F3/08
European ClassificationA45F3/08
Legal Events
May 23, 1983AS06Security interest
Owner name: FIRST BANK (N.A.)
Effective date: 19830301
Owner name: JANSPORT CORP.
May 23, 1983ASAssignment
Owner name: FIRST BANK (N.A.)
Effective date: 19830301
May 24, 1982AS06Security interest
Owner name: DOWNERS, INC.
Effective date: 19820421
May 24, 1982ASAssignment
Effective date: 19820421
Apr 30, 1982AS02Assignment of assignor's interest
Effective date: 19820422
Apr 30, 1982ASAssignment
Effective date: 19820422